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Koenig JL, Pappas L, Yeap BY, Clark JW, Allen JN, Wo JY, Ryan DP, Blaszkowsky LS, Giantonio B, Weekes C, Klempner S, Roberts HJ, Drapek LC, Ly L, Meurer J, Corcoran R, Mehta A, Ting D, Hong TS, Parikh AR. Association between Liver Metastases and Treatment Response in Patients with Metastatic, Microsatellite Stable Colorectal Cancer Treated with Radiation Therapy and Dual Immune Checkpoint Blockade. Int J Radiat Oncol Biol Phys 2023; 117:e308-e309. [PMID: 37785117 DOI: 10.1016/j.ijrobp.2023.06.2333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
PURPOSE/OBJECTIVE(S) Most patients with metastatic colorectal cancer (CRC) have microsatellite stable (MSS) disease with a limited response to immune checkpoint inhibitors (ICIs). In our phase 2 trial (NCT03104439), 27 patients with metastatic MSS CRC received ipilimumab, nivolumab, and RT (24 Gy/3 fractions) on C2D1 with a disease control rate (DCR) of 37% (10/27) and overall response rate (ORR) of 15% (4/27). Our follow up phase 2 study with ipilimumab, nivolumab, and RT moved to C1D1 (NCT04361162) showed a DCR of 33% (10/30) and an ORR of 13% (4/30). Clinical and preclinical data suggest liver metastases are less responsive to systemic ICIs and complementary liver-directed RT can potentially overcome this effect. To address this, we investigated the association between liver metastases and response rates among patients treated with and without liver-directed RT in a pooled analysis of our phase 2 studies of nivolumab and ipilimumab with RT. MATERIALS/METHODS In this pooled secondary analysis of two open-label, single-arm, phase 2 studies, eligible patients had metastatic MSS CRC, ECOG PS 0-1, and progressed on at least one line of chemotherapy. Treatment consisted of ipilimumab 1 mg/kg q6weeks for 4 cycles, nivolumab 240 mg q2weeks on a 6-week cycle, and RT (24 Gy/3 fractions) on C1D1 or C2D1 to one site. Responses were defined outside of the RT field by RECIST 1.1 with centrally reviewed imaging q3months. ORR/DCR and PFS/OS were compared between patients with and without liver metastases with the Fisher's exact and log-rank tests, respectively. P-values are two-sided. RESULTS We treated 57 patients (median age 57 years [range, 26-85], 61% male, 88% white, 65% with liver metastases) from 07/2017 to 05/2022. Patients received a median of 3 (range, 1-10) prior lines of systemic therapy. The combined ORR was 14% (8/57; 95% CI, 6-26%) and DCR was 35% (20/57; 95% CI, 23-49%). The ORR was 30% (6/20; 95% CI, 12-54%) in patients without liver metastases and 5% (2/37; 95% CI, 1-18%) in patients with liver metastases (p = 0.017). The DCR was 55% (11/20; 95% CI, 32-77%) in patients without liver metastases and 24% (9/37; 94% CI, 12-41%) in patients with liver metastases (p = 0.040). 76% (28/37) of patients with liver metastases received liver-directed RT including 2/2 (100%) patients with a PR. The ORR was 0% in patients with liver metastases without liver-directed RT. The median PFS was 1.8 months (95% CI, 1.2-2.4 months) and OS was 9.8 months (95% CI, 6.8-12.8). OS was longer in patients without liver metastases (median 13.6 v 6.8 months, p = 0.010) and in patients treated with liver-directed RT among those with liver metastases (median 7.5 months v 4.5 months, p = 0.025). CONCLUSION Among patients with metastatic MSS CRC treated with ICIs and RT in two phase 2 studies, ORR, DCR, and OS are significantly higher in patients without liver metastases. Liver-directed RT may improve ICI efficacy and OS in patients with liver metastases. Further analysis of PFS and prospective study of ICIs with comprehensive liver-directed RT are warranted.
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Affiliation(s)
- J L Koenig
- Harvard Radiation Oncology Program, Boston, MA
| | - L Pappas
- Department of Medicine, Division of Hematology & Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - B Y Yeap
- Department of Medicine, Division of Hematology & Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA; Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA
| | - J W Clark
- Department of Medicine, Division of Hematology & Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - J N Allen
- Department of Medicine, Division of Hematology & Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - J Y Wo
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - D P Ryan
- Department of Medicine, Division of Hematology & Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - L S Blaszkowsky
- Department of Medicine, Division of Hematology & Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - B Giantonio
- Department of Medicine, Division of Hematology & Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - C Weekes
- Department of Medicine, Division of Hematology & Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - S Klempner
- Department of Medicine, Division of Hematology & Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - H J Roberts
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - L C Drapek
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - L Ly
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA
| | - J Meurer
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA
| | - R Corcoran
- Department of Medicine, Division of Hematology & Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - A Mehta
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA; The Broad Institute, Cambridge, MA
| | - D Ting
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA
| | - T S Hong
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - A R Parikh
- Department of Medicine, Division of Hematology & Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA
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Dunn FS, Kenchington CG, Parry LA, Clark JW, Kendall RS, Wilby PR. A crown-group cnidarian from the Ediacaran of Charnwood Forest, UK. Nat Ecol Evol 2022; 6:1095-1104. [PMID: 35879540 PMCID: PMC9349040 DOI: 10.1038/s41559-022-01807-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 05/23/2022] [Indexed: 11/17/2022]
Abstract
Cnidarians are a disparate and ancient phylum, encompassing corals and jellyfish, and occupy both the pelagic and benthic realms. They have a rich fossil record from the Phanerozoic eon lending insight into the early history of the group but, although cnidarians diverged from other animals in the Precambrian period, their record from the Ediacaran period (635–542 million years ago) is controversial. Here, we describe a new fossil cnidarian—Auroralumina attenboroughii gen. et sp. nov.—from the Ediacaran of Charnwood Forest (557–562 million years ago) that shows two bifurcating polyps enclosed in a rigid, polyhedral, organic skeleton with evidence of simple, densely packed tentacles. Auroralumina displays a suite of characters allying it to early medusozoans but shows others more typical of Anthozoa. Phylogenetic analyses recover Auroralumina as a stem-group medusozoan and, therefore, the oldest crown-group cnidarian. Auroralumina demonstrates both the establishment of the crown group of an animal phylum and the fixation of its body plan tens of millions of years before the Cambrian diversification of animal life. A new fossil cnidarian, Auroralumina attenboroughi, from the Ediacaran of Charnwood Forest, UK, described as showing mosaic anthozoan and medusozoan characters, is the oldest yet-known crown-group cnidarian.
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Affiliation(s)
- F S Dunn
- Oxford University Museum of Natural History, University of Oxford, Oxford, UK.
| | - C G Kenchington
- Department of Earth Sciences, University of Cambridge, Cambridge, UK
| | - L A Parry
- Department of Earth Sciences, University of Oxford, Oxford, UK
| | - J W Clark
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - R S Kendall
- British Geological Survey, Cardiff University, Cardiff, UK
| | - P R Wilby
- British Geological Survey, Nicker Hill, Keyworth, Nottingham, UK.,Department of Geology, University of Leicester, Leicester, UK
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Khushalani N, Gerber D, Clark JW, Messersmith W, Heinrichs T, Zion N, Berlin J. QIM22-197: Protected Time and Provision of Resources at National Comprehensive Cancer Network (NCCN) Member Institutions (MIs). J Natl Compr Canc Netw 2022. [DOI: 10.6004/jnccn.2021.7226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
| | - David Gerber
- 2 UT Southwestern Simmons Comprehensive Cancer Center, Dallas, TX
| | - Jeffery W. Clark
- 3 Dana-Farber/Brigham and Women’s Cancer Center, Massachusetts General Hospital Cancer Center, Boston, MA
| | | | | | - Nicole Zion
- 5 National Comprehensive Cancer Network, Plymouth Meeting, PA
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Shaw AT, Riely GJ, Bang YJ, Kim DW, Camidge DR, Solomon BJ, Varella-Garcia M, Iafrate AJ, Shapiro GI, Usari T, Wang SC, Wilner KD, Clark JW, Ou SHI. Crizotinib in ROS1-rearranged advanced non-small-cell lung cancer (NSCLC): updated results, including overall survival, from PROFILE 1001. Ann Oncol 2019; 30:1121-1126. [PMID: 30980071 PMCID: PMC6637370 DOI: 10.1093/annonc/mdz131] [Citation(s) in RCA: 310] [Impact Index Per Article: 62.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND In the ongoing phase I PROFILE 1001 study, crizotinib showed antitumor activity in patients with ROS1-rearranged advanced non-small-cell lung cancer (NSCLC). Here, we present updated antitumor activity, overall survival (OS) and safety data (additional 46.2 months follow-up) for patients with ROS1-rearranged advanced NSCLC from PROFILE 1001. PATIENTS AND METHODS ROS1 status was determined by FISH or reverse transcriptase-polymerase chain reaction. All patients received crizotinib at a starting dose of 250 mg twice daily. RESULTS Fifty-three patients received crizotinib, with a median duration of treatment of 22.4 months. At data cut-off, treatment was ongoing in 12 patients (23%). The objective response rate (ORR) was 72% [95% confidence interval (CI), 58% to 83%], including six confirmed complete responses and 32 confirmed partial responses; 10 patients had stable disease. Responses were durable (median duration of response 24.7 months; 95% CI, 15.2-45.3). ORRs were consistent across different patient subgroups. Median progression-free survival was 19.3 months (95% CI, 15.2-39.1). A total of 26 deaths (49%) occurred (median follow-up period of 62.6 months), and of the remaining 27 patients (51%), 14 (26%) were in follow-up at data cut-off. Median OS was 51.4 months (95% CI, 29.3 to not reached) and survival probabilities at 12, 24, 36, and 48 months were 79%, 67%, 53%, and 51%, respectively. No correlation was observed between OS and specific ROS1 fusion partner. Treatment-related adverse events (TRAEs) were mainly grade 1 or 2, per CTCAE v3.0. There were no grade ≥4 TRAEs and no TRAEs associated with permanent discontinuation. No new safety signals were reported with long-term crizotinib treatment. CONCLUSIONS These findings serve as a new benchmark for OS in ROS1-rearranged advanced NSCLC, and continue to show the clinically meaningful benefit and safety of crizotinib in this molecular subgroup. TRIAL REGISTRATION NUMBER ClinicalTrials.gov identifier NCT00585195.
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Affiliation(s)
- A T Shaw
- Department of Medicine, Massachusetts General Hospital Cancer Center, Boston.
| | - G J Riely
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, USA
| | - Y-J Bang
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, South Korea
| | - D-W Kim
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, South Korea
| | - D R Camidge
- Division of Medical Oncology, University of Colorado Cancer Center, Aurora, USA
| | - B J Solomon
- Department of Medical Oncology, Peter MacCallum Cancer Centre, Melbourne, Australia
| | - M Varella-Garcia
- Division of Medical Oncology, University of Colorado Cancer Center, Aurora, USA
| | - A J Iafrate
- Department of Medicine, Massachusetts General Hospital Cancer Center, Boston
| | - G I Shapiro
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, USA
| | - T Usari
- Pfizer Oncology, Milan, Italy
| | | | | | - J W Clark
- Department of Medicine, Massachusetts General Hospital Cancer Center, Boston
| | - S-H I Ou
- Chao Family Comprehensive Cancer Center, University of California, Irvine, USA
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Stewart EM, Mellor A, Jenkins MM, Clark JW, Norton PJ, Baucom DH, Drummond SP. 0420 WHO ARE THE PARTNERS? A SLEEP PROFILE OF PARTNERS OF INDIVIDUALS SEEKING TREATMENT FOR INSOMNIA. Sleep 2017. [DOI: 10.1093/sleepj/zsx050.419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Affiliation(s)
- J W Clark
- Clinical Research Branch, National Cancer Institute, Frederick, Md
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Ou SHI, Jänne PA, Bartlett CH, Tang Y, Kim DW, Otterson GA, Crinò L, Selaru P, Cohen DP, Clark JW, Riely GJ. Clinical benefit of continuing ALK inhibition with crizotinib beyond initial disease progression in patients with advanced ALK-positive NSCLC. Ann Oncol 2015; 25:415-22. [PMID: 24478318 DOI: 10.1093/annonc/mdt572] [Citation(s) in RCA: 178] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Crizotinib is approved to treat advanced ALK-positive non-small-cell lung cancer (NSCLC), but most patients ultimately develop progressive disease (PD). We investigated whether continuing ALK inhibition with crizotinib beyond PD (CBPD) is clinically beneficial and attempted to identify clinicopathologic characteristics associated with patients who experience clinical benefit. PATIENTS AND METHODS Patients with advanced ALK-positive NSCLC enrolled in two ongoing multicenter, single-arm trials who developed RECIST-defined PD were allowed to continue crizotinib if they were deriving ongoing clinical benefit. In the present retrospective analysis, continuation of CBPD was defined as >3 weeks of crizotinib treatment after PD documentation. Patients who had PD as best response to initial crizotinib treatment were excluded. Baseline and post-progression characteristics, sites of PD, and overall survival (OS) were compared in patients who continued CBPD versus those who did not. The impact of continuing CBPD on OS after adjusting for potential confounding factors was assessed. RESULTS Among 194 crizotinib-treated patients with RECIST-defined PD, 120 (62%) continued CBPD. A significantly higher proportion of patients who continued CBPD than patients who did not had an ECOG performance status (PS) of 0/1 at PD (96% versus 82%; P=0.02). CBPD patients had significantly longer OS from the time of PD [median 16.4 versus 3.9 months; hazards ratio (HR) 0.27, 95% confidence interval (CI): 0.17-0.42; P<0.0001] and from the time of initial crizotinib treatment (median 29.6 versus 10.8 months; HR 0.30, 95% CI: 0.19-0.46; P<0.0001). The multiple-covariate Cox regression analysis revealed that CBPD remained significantly associated with improved OS after adjusting for relevant factors. CONCLUSIONS Patients who continued CBPD were more likely to have good ECOG PS (0/1) at the time of PD. Continuing ALK inhibition with crizotinib after PD may provide survival benefit to patients with advanced ALK-positive NSCLC.
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Affiliation(s)
- S-H I Ou
- Chao Family Comprehensive Cancer Center, University of California at Irvine, Irvine
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Blaszkowsky LS, Ryan DP, Szymonifka J, Borger DR, Zhu AX, Clark JW, Kwak EL, Mamon HJ, Allen JN, Vasudev E, Shellito PC, Cusack JC, Berger DL, Hong TS. Phase I/II study of neoadjuvant bevacizumab, erlotinib and 5-fluorouracil with concurrent external beam radiation therapy in locally advanced rectal cancer. Ann Oncol 2014; 25:121-6. [PMID: 24356623 DOI: 10.1093/annonc/mdt516] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND To determine the maximal tolerated dose of erlotinib when added to 5-fluorouracil (5-FU) chemoradiation and bevacizumab and safety and efficacy of this combination in patients with locally advanced rectal cancer. PATIENTS AND METHODS Patients with Magnetic resonance imaging (MRI) or ultrasound defined T3 or T4 adenocarcinoma of the rectum and without evidence of metastatic disease were enrolled. Patients received infusional 5-FU 225 mg/M2/day continuously, along with bevacizumab 5 mg/kg days 14, 1, 15 and 29. Standard radiotherapy was administered to 50.4 Gy in 28 fractions. Erlotinib started at a dose of 50 mg orally daily and advanced by 50 mg increments in the subsequent cohort. Open total mesorectal excision was carried out 6-9 weeks following the completion of chemoradiation. RESULTS Thirty-two patients received one of three dose levels of erlotinib. Erlotinib dose level of 100 mg was determined to be the maximally tolerated dose. Thirty-one patients underwent resection of the primary tumor, one refused resection. Twenty-seven patients completed study therapy, all of whom underwent resection. At least one grade 3-4 toxicity occurred in 46.9% of patients. Grade 3-4 diarrhea occurred in 18.8%. The pathologic complete response (pCR) for all patients completing study therapy was 33%. With a median follow-up of 2.9 years, there are no documented local recurrences. Disease-free survival at 3 years is 75.5% (confidence interval: 55.1-87.6%). CONCLUSIONS Erlotinib added to infusional 5-FU, bevacizumab and radiation in patients with locally advanced rectal cancer is relatively well tolerated and associated with an encouraging pCR.
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Hezel AF, Noel MS, Allen JN, Abrams TA, Yurgelun M, Faris JE, Goyal L, Clark JW, Blaszkowsky LS, Murphy JE, Zheng H, Khorana AA, Connolly GC, Hyrien O, Baran A, Herr M, Ng K, Sheehan S, Harris DJ, Regan E, Borger DR, Iafrate AJ, Fuchs C, Ryan DP, Zhu AX. Phase II study of gemcitabine, oxaliplatin in combination with panitumumab in KRAS wild-type unresectable or metastatic biliary tract and gallbladder cancer. Br J Cancer 2014; 111:430-6. [PMID: 24960403 PMCID: PMC4119993 DOI: 10.1038/bjc.2014.343] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 04/30/2014] [Accepted: 05/12/2014] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Current data suggest that platinum-based combination therapy is the standard first-line treatment for biliary tract cancer. EGFR inhibition has proven beneficial across a number of gastrointestinal malignancies; and has shown specific advantages among KRAS wild-type genetic subtypes of colon cancer. We report the combination of panitumumab with gemcitabine (GEM) and oxaliplatin (OX) as first-line therapy for KRAS wild-type biliary tract cancer. METHODS Patients with histologically confirmed, previously untreated, unresectable or metastatic KRAS wild-type biliary tract or gallbladder adenocarcinoma with ECOG performance status 0-2 were treated with panitumumab 6 mg kg(-1), GEM 1000 mg m(-2) (10 mg m(-2) min(-1)) and OX 85 mg m(-2) on days 1 and 15 of each 28-day cycle. The primary objective was to determine the objective response rate by RECIST criteria v.1.1. Secondary objectives were to evaluate toxicity, progression-free survival (PFS), and overall survival. RESULTS Thirty-one patients received at least one cycle of treatment across three institutions, 28 had measurable disease. Response rate was 45% and disease control rate was 90%. Median PFS was 10.6 months (95% CI 5-24 months) and median overall survival 20.3 months (95% CI 9-25 months). The most common grade 3/4 adverse events were anaemia 26%, leukopenia 23%, fatigue 23%, neuropathy 16% and rash 10%. CONCLUSIONS The combination of gemcitabine, oxaliplatin and panitumumab in KRAS wild type metastatic biliary tract cancer showed encouraging efficacy, additional efforts of genetic stratification and targeted therapy is warranted in biliary tract cancer.
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Affiliation(s)
- A F Hezel
- Division of Hematology/Oncology, James P. Wilmot Cancer Center, University of Rochester, Rochester, NY, USA
| | - M S Noel
- Division of Hematology/Oncology, James P. Wilmot Cancer Center, University of Rochester, Rochester, NY, USA
| | - J N Allen
- Division of Hematology/Oncology, Massachusetts General Hospital, Boston, MA, USA
| | - T A Abrams
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - M Yurgelun
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - J E Faris
- Division of Hematology/Oncology, Massachusetts General Hospital, Boston, MA, USA
| | - L Goyal
- Division of Hematology/Oncology, Massachusetts General Hospital, Boston, MA, USA
| | - J W Clark
- Division of Hematology/Oncology, Massachusetts General Hospital, Boston, MA, USA
| | - L S Blaszkowsky
- Division of Hematology/Oncology, Massachusetts General Hospital, Boston, MA, USA
| | - J E Murphy
- Division of Hematology/Oncology, Massachusetts General Hospital, Boston, MA, USA
| | - H Zheng
- Biostatistics Center, Massachusetts General Hospital, Boston, MA, USA
| | - A A Khorana
- Taussig Cancer Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - G C Connolly
- Division of Hematology/Oncology, James P. Wilmot Cancer Center, University of Rochester, Rochester, NY, USA
| | - O Hyrien
- Department of Biostatistics and Computational Biology, University of Rochester Medical Center, Rochester, NY, USA
| | - A Baran
- Department of Biostatistics and Computational Biology, University of Rochester Medical Center, Rochester, NY, USA
| | - M Herr
- Department of Public Health Sciences, University of Rochester Medical Center, Rochester, NY, USA
| | - K Ng
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - S Sheehan
- Division of Hematology/Oncology, Massachusetts General Hospital, Boston, MA, USA
| | - D J Harris
- Division of Hematology/Oncology, Massachusetts General Hospital, Boston, MA, USA
| | - E Regan
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - D R Borger
- Department of Pathology, Massachusetts General Hospital, Boston, MA, USA
| | - A J Iafrate
- Department of Pathology, Massachusetts General Hospital, Boston, MA, USA
| | - C Fuchs
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - D P Ryan
- Division of Hematology/Oncology, Massachusetts General Hospital, Boston, MA, USA
| | - A X Zhu
- Division of Hematology/Oncology, Massachusetts General Hospital, Boston, MA, USA
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Shashkin AA, Dolgopolov VT, Clark JW, Shaginyan VR, Zverev MV, Khodel VA. Merging of Landau levels in a strongly interacting two-dimensional electron system in silicon. Phys Rev Lett 2014; 112:186402. [PMID: 24856708 DOI: 10.1103/physrevlett.112.186402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Indexed: 06/03/2023]
Abstract
We show that the merging of the spin- and valley-split Landau levels at the chemical potential is an intrinsic property of a strongly interacting two-dimensional electron system in silicon. Evidence for the level merging is given by available experimental data.
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Affiliation(s)
- A A Shashkin
- Institute of Solid State Physics, Chernogolovka, Moscow District 142432, Russia
| | - V T Dolgopolov
- Institute of Solid State Physics, Chernogolovka, Moscow District 142432, Russia and Moscow Institute of Physics and Technology, Dolgoprudny, Moscow District 141700, Russia
| | - J W Clark
- McDonnell Center for the Space Sciences & Department of Physics, Washington University, Saint Louis, Missouri 63130, USA
| | - V R Shaginyan
- Petersburg Nuclear Physics Institute, NRC Kurchatov Institute, Gatchina 188300, Russia and Clark Atlanta University, Atlanta, Georgia 30314, USA
| | - M V Zverev
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow District 141700, Russia and NRC Kurchatov Institute, Moscow 123182, Russia
| | - V A Khodel
- NRC Kurchatov Institute, Moscow 123182, Russia
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Clark JW, Kioko E, Odemba N, Ngere F, Kamanza J, Oyugi E, Kerich G, Kimbita E, Bast JD. First report of the visceral leishmaniasis vector Phlebotomus martini (Diptera: Psychodidae) in Tanzania. J Med Entomol 2013; 50:212-216. [PMID: 23427673 DOI: 10.1603/me12147] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Phlebotomus martini is a known vector of visceral leishmaniasis caused by Leishmania donovani in sub-Saharan Africa. The disease is known to be endemic in areas of north and south Sudan, Kenya, Ethiopia, Uganda, and Somalia but has not been reported from Tanzania. In this report we present the first documented collection of P. martini and P. vansomerenae in Tanzania. Sand flies were collected using standard dry-ice baited CDC light traps (John W. Hock Company, Gainesville, FL) from five sampling sites in the Arusha and Kilimanjaro regions from 14 to 20 July 2010. Phlebotomus martini was collected from all sites and represented 6.6% of the total identified sand flies. Phlebotomus martini ranged from 4.5 to 9.4% of the total identified catch from the four sites in the Kilimanjaro region and 17.9% of the total identified catch at the one collection site in the Arusha region. In addition, one male specimen of the sibling species, Phlebotomus vansomerenae, was found at Chemka Springs in the Kilimanjaro region. These data indicate the presence of an established population(s) of P. martini in northern Tanzania that could support L. donovani transmission in an area with no prior case history of visceral leishmaniasis.
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Affiliation(s)
- J W Clark
- Material has been reviewed by the Walter Reed Army Institute of Research. The opinions or assertions contained herein are the private views of the author, and are not to be construed as official, or as US Army Medical Research Unit-Kenya/Kenya Medical Research Institute, Department of Entomology and Vector Biology, PO Box 54, Kisumu, Kenya.
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Shaginyan VR, Amusia MY, Clark JW, Msezane AZ, Popov KG, Zverev MV, Khodel VA. Comment on "Zeeman-driven Lifshitz transition: a model for the experimentally observed Fermi-surface reconstruction in YbRh2Si2". Phys Rev Lett 2011; 107:279701-279702. [PMID: 22243331 DOI: 10.1103/physrevlett.107.279701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Indexed: 05/31/2023]
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Abstract
A thorough understanding of ventricular interaction and the effects of septal function on right and left ventricular performance in the human heart requires measurement of interventricular pressure gradients using high fidelity pressure transducers. The advent of newer echocardiographic techniques provides an opportunity to combine high resolution images with bi-ventricular catheterization data in the cardiac catheterization laboratory, and obtain the detailed hemodynamic and echocardiographic information necessary to more fully understand the clinical manifestations of normal and abnormal septal and free wall mechanical function. We have anticipated these developments and modified the description of heart mechanics in our integrated multi-scale model of the human cardio-respiratory system (H-CRS) to closely analyze how the mechanical properties of the inter-ventricular septum affect the work, energy utilization, and oxygen consumption of the atria, ventricles, septum, and each ventricular free wall. Combined with the H-CRS model, these modifications allow one to observe how tissue properties of the septum affect the entire heart and circulation. For example, the normal septum transfers energy from the left to the right ventricle, and assists the pre-load of both, acting as a third pump. Diseases that increase septal elastance cause abnormalities resembling left ventricular diastolic dysfunction (LVDD), including a decrease in cardiac output and an increase in pulmonary pressures despite a normal left ventricular ejection fraction. Similar applications of the H-CRS model to other regional disorders such as hypertrophic obstructive cardiomyopathy and myocardial infarction might likewise allow one to study their clinical implications in greater detail.
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Affiliation(s)
- C Luo
- Department of Electrical and Computer Engineering, Rice University, 6100 Main St, Houston, TX 77005-1892, USA.
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14
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Enzinger PC, Ryan DP, Clark JW, Muzikansky A, Earle CC, Kulke MH, Meyerhardt JA, Blaszkowsky LS, Zhu AX, Fidias P, Vincitore MM, Mayer RJ, Fuchs CS. Weekly docetaxel, cisplatin, and irinotecan (TPC): results of a multicenter phase II trial in patients with metastatic esophagogastric cancer. Ann Oncol 2009; 20:475-80. [PMID: 19139178 DOI: 10.1093/annonc/mdn658] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Recent studies have examined the addition of docetaxel to fluorouracil and cisplatin in advanced esophagogastric cancer. PATIENTS AND METHODS We carried out a phase I dose-escalation study of weekly docetaxel, cisplatin, and irinotecan (TPC), given on days 1 and 8 every 3 weeks, in patients with chemonaive solid tumors. Subsequently, we completed a multiinstitutional phase II study of TPC in patients with previously untreated, metastatic esophagogastric cancer. RESULTS Thirty-nine patients were enrolled in the phase I trial; a weekly schedule of TPC was well tolerated. On that basis, docetaxel 30 mg/m(2), cisplatin 25 mg/m(2), and irinotecan 65 mg/m(2) were selected for the phase II trial, where in the first 18 patients irinotecan 65 mg/m(2) caused too much diarrhea and was reduced to 50 mg/m(2). Among 56 eligible patients with previously untreated, metastatic esophagogastric cancer enrolled in the phase II trial, three complete and 27 partial responses were observed (overall response rate=54%), and 15 patients (30%) had stable disease. Median progression-free survival was 7.1 months, and median survival was 11.9 months. At the final irinotecan dose of 50 mg/m(2), grade 3 or higher toxicity included diarrhea (26%), neutropenia (21%), nausea (18%), fatigue (16%), anorexia (13%), and thrombosis/embolism (13%). CONCLUSIONS Weekly TPC is an active and well-tolerated regimen for patients with esophagogastric cancer.
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Affiliation(s)
- P C Enzinger
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
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15
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Chang G, Pan T, Chang T, Clark JW, Mawlawi O. SU-GG-I-136: Improving SNR by Using Super-Resolution (SR) Incorporated Image Reconstruction in PET Imaging. Med Phys 2008. [DOI: 10.1118/1.2961534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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16
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Solís MA, de Llano M, Clark JW, Baker GA. Improved quantum hard-sphere ground-state equations of state. Phys Rev E Stat Nonlin Soft Matter Phys 2007; 76:031125. [PMID: 17930217 DOI: 10.1103/physreve.76.031125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Indexed: 05/25/2023]
Abstract
The London ground-state energy formula as a function of number density for a system of identical boson hard spheres, corrected for the reduced mass of a pair of particles in a "sphere-of-influence" picture, and generalized to fermion hard-sphere systems with two and four intrinsic degrees of freedom, has a double-pole at the ultimate regular (or periodic, e.g., face-centered-cubic) close-packing density usually associated with a crystalline branch. Improved fluid branches are constructed based upon exact, field-theoretic perturbation-theory low-density expansions for many-boson and many-fermion systems, extrapolated to intermediate densities via Padé and other approximants, but whose ultimate density is irregular or random closest close-packing as suggested in studies of a classical system of hard spheres. Results show substantially improved agreement with the best available Green-function Monte Carlo and diffusion Monte Carlo simulations for bosons, as well as with ladder, variational Fermi hypernetted chain, and so-called L -expansion data for two-component fermions.
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Affiliation(s)
- M A Solís
- Department of Physics, Washington University, St. Louis, Missouri 63130, USA
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17
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Khodel VA, Clark JW, Li H, Zverev MV. Merging of single-particle levels and non-Fermi-liquid behavior of finite Fermi systems. Phys Rev Lett 2007; 98:216404. [PMID: 17677793 DOI: 10.1103/physrevlett.98.216404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Indexed: 05/16/2023]
Abstract
We examine the problem of finite Fermi systems having a degenerate single-particle spectrum and show that the Landau approach, applied to such a system, admits the possibility of merging single-particle levels. It is demonstrated that the opportunity for this behavior is widespread in quantum many-body systems. The salient feature of the phenomenon is the occurrence of nonintegral quasiparticle occupation numbers, leading to a radical alteration of the standard quasiparticle picture. Implications of this alteration are considered for nuclear, atomic, and solid-state systems.
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Affiliation(s)
- V A Khodel
- Russian Research Centre Kurchatov Institute, Moscow, 123182, Russia
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18
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Luo C, Ware DL, Zwischenberger JB, Clark JW. Using a Human Cardiopulmonary Model to Study and Predict Normal and Diseased Ventricular Mechanics, Septal Interaction, and Atrio-Ventricular Blood Flow Patterns. ACTA ACUST UNITED AC 2007; 7:17-31. [PMID: 17334942 DOI: 10.1007/s10558-007-9025-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We upgraded our human cardiopulmonary (CP) model with additional data that enables it to more accurately simulate normal physiology. We then tested its ability to explain human disease by changing two parameter values that decrease ventricular compliance, and found that it could predict many of the hemodynamic, gas exchange, and autonomic abnormalities found in patients with left ventricular diastolic dysfunction (LVDD). The newly incorporated information includes high-fidelity pressure tracings simultaneously recorded from the RV and LV of a normal human in a cardiac catheterization laboratory, Doppler echocardiographic inlet flow velocity patterns, measures of right and left ventricular impedance, and atrial volumes. The revised cardiovascular section details the hemodynamics of a normal subject to the extent that it can now explain the effects of septal compliance on ventricular interaction, the differences in left and right ventricular pressure development, and venous blood gas mixing in the right atrium. The model can isolate the highly interrelated features of normal and abnormal physiology, and simultaneously demonstrate their interaction in a manner that would be very difficult or impossible using an intact organism. It may therefore help physicians and scientists understand, diagnose, and improve their treatment of complicated cardiovascular and pulmonary diseases. It could also simulate the hemodynamic and respiratory effects of ventricular and pulmonary assist devices, and thus help with their development.
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Affiliation(s)
- C Luo
- Department of Electrical and Computer Engineering, Rice University, 6100 Main St., Houston, TX 77005-1892, USA
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Strumberg D, Awada A, Hirte H, Clark JW, Seeber S, Piccart P, Hofstra E, Voliotis D, Christensen O, Brueckner A, Schwartz B. Pooled safety analysis of BAY 43-9006 (sorafenib) monotherapy in patients with advanced solid tumours: Is rash associated with treatment outcome? Eur J Cancer 2006; 42:548-56. [PMID: 16426838 DOI: 10.1016/j.ejca.2005.11.014] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2005] [Revised: 11/08/2005] [Accepted: 11/11/2005] [Indexed: 10/25/2022]
Abstract
In this analysis of the safety and efficacy of BAY 43-9006 (sorafenib) -- a novel, oral multi-kinase inhibitor with effects on tumour and its vasculature -- pooled data were obtained from four phase I dose-escalation trials. Time to progression (TTP) was compared in patients with/without grade 2 skin toxicity/diarrhoea. Grade 3 hand-foot skin reactions (HFS; 8%) and diarrhoea (6%) were common. At the recommended 400mg bid dose for phase II/III trials (RDP), 15% of patients experienced grade 2/3 HFS, and 24% experienced grade 2/3 diarrhoea. Sorafenib induced stable disease for 6 months in 12% of patients (6% stabilized for 1 year). Patients receiving sorafenib doses at or close to the RDP, who experienced skin toxicity/diarrhoea, had a significantly increased TTP compared with patients without such toxicity (P < 0.05). Sorafenib was well tolerated at the RDP, and induced sustained disease stabilization, particularly in patients with skin toxicity/diarrhoea.
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Affiliation(s)
- D Strumberg
- Department of Internal Medicine and Medical Oncology, West German Cancer Center, University Medical School of Essen, Essen, Germany.
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Luo C, Clark JW, Heming TA, Bidani A. A macrophage cell model for pH and volume regulation. J Theor Biol 2006; 238:449-63. [PMID: 16043192 DOI: 10.1016/j.jtbi.2005.06.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2004] [Revised: 05/25/2005] [Accepted: 06/03/2005] [Indexed: 11/16/2022]
Abstract
A whole-cell model of a macrophage (mphi) is developed to simulate pH and volume regulation during a NH4Cl prepulse challenge. The cell is assumed spherical, with a plasma membrane that separates the cytosolic and extracellular bathing media. The membrane contains background currents for Na+, K+ and Cl-, a Na(+)-K+ pump, a V-type H(+)-extruder (V-ATPase), and a leak pathway for NH4+. Cell volume is controlled by instantaneous osmotic balance between cytosolic and extracellular osmolytes. Simulations reveal that the mphi model can mimic alterations in measured pH(i) and cell volume (Vol(i)) data during and after delivery of an ammonia prepulse, which induces an acid load within the cell. Our analysis indicates that there are substantial problems in quantifying transporter-mediated H+ efflux solely from experimental observations of pH(i) recovery, as is commonly done in practice. Problems stemming from the separation of effects arise, since there is residual NH4+ dissociation to H+ inside the mphi during pH(i) recovery, as well as, proton extrusion via the V-ATPase. The core assumption of conventional measurement techniques used to estimate the H+ extrusion current (I(H)) is that the recovery phase is solely dependent on transporter-mediated H+ extrusion. However, our model predictions suggest that there are major problems in using this approach, due to the complex interactions between I(H), NH3/NH4+ buffering and NH3/NH4+ efflux during the active acid extrusion phase. That is, the conventional buffer capacity-based I(H) estimation must also take into account the perturbation that a prepulse challenge brings to the cytoplasmic acid buffer itself. The importance of this whole-cell model of mphipH(i) and volume regulation lies in its potential for extension to the characterization of several other types of non-excitable cells, such as the microglia (brain macrophage) and the T-lymphocyte.
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Affiliation(s)
- C Luo
- Department of Electrical Engineering, Rice University, Houston, TX 77005, USA
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21
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Penson RT, Seiden MV, Matulonis UA, Appleman LJ, Fuller AF, Goodman A, Campos SM, Clark JW, Roche M, Eder JP. A phase I clinical trial of continual alternating etoposide and topotecan in refractory solid tumours. Br J Cancer 2005; 93:54-9. [PMID: 15986034 PMCID: PMC2361482 DOI: 10.1038/sj.bjc.6602671] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The goal of this phase I study was to develop a novel schedule using oral etoposide and infusional topotecan as a continually alternating schedule with potentially optimal reciprocal induction of the nontarget topoisomerase. The initial etoposide dose was 15 mg m(-2) b.i.d. days (D)1-5 weeks 1,3,5,7,9 and 11, escalated 5 mg per dose per dose level (DL). Topotecan in weeks 2,4,6,8,10 and 12 was administered by 96 h infusion at an initial dose of 0.2 mg m(-2) day(-1) with a dose escalation of 0.1, then at 0.05 mg m(-2) day(-1). Eligibility criteria required no organ dysfunction. Two dose reductions or delays were allowed. A total of 36 patients with a median age of 57 (22-78) years, received a median 8 (2-19) weeks of chemotherapy. At DL 6, dose-limiting toxicities consisted of grade 3 nausea, vomiting and intolerable fatigue. Three patients developed a line-related thrombosis or infection and one subsequently developed AML. There was no febrile neutropenia. There were six radiologically confirmed responses (18%) and 56% of patients demonstrated a response or stable disease, typically with only modest toxicity. Oral etoposide 35 mg m(-2) b.i.d. D1-5 and 1.8 mg m(-2) 96 h (total dose) infusional topotecan D8-11 can be administered on an alternating continual weekly schedule for at least 12 weeks, with promising clinical activity.
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Affiliation(s)
- R T Penson
- Division of Hematology and Oncology, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.
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22
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Hamilton AL, Eder JP, Pavlick AC, Clark JW, Liebes L, Garcia-Carbonero R, Chachoua A, Ryan DP, Soma V, Farrell K, Kinchla N, Boyden J, Yee H, Zeleniuch-Jacquotte A, Wright J, Elliott P, Adams J, Muggia FM. Proteasome Inhibition With Bortezomib (PS-341): A Phase I Study With Pharmacodynamic End Points Using a Day 1 and Day 4 Schedule in a 14-Day Cycle. J Clin Oncol 2005; 23:6107-16. [PMID: 16135477 DOI: 10.1200/jco.2005.01.136] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PurposeWe performed a phase I study of a day (D) 1 and D4 bortezomib administration once every 2 weeks to determine the recommended phase II dose and toxicity profile, and the extent of 20S proteasome inhibition obtained.Patients and MethodsPatients with solid tumors or lymphomas were treated with bortezomib at 0.25 to 1.9 mg/m2on D1 and D4, every 2 weeks. 20S proteasome levels in blood were assayed at baseline and at 1, 4, and 24 hours postdose in cycle 1.ResultsOn this D1 and D4 every 2 weeks' schedule, dose-limiting toxicity (DLT) was evident at the 1.75 and 1.9 mg/m2dose levels, most commonly in patients receiving individual total doses ≥ 3.0 mg. The main DLT was peripheral neuropathy evident at the higher doses and in patients previously exposed to neurotoxic agents. Other DLTs included diarrhea and fatigue; grade 3 thrombocytopenia was also noted. Reversible inhibition of 20S proteasome activity was dose dependent and best fit a total dose (mg) per fraction rather than mg/m2; 70% of baseline activity was inhibited by a dose of 3.0 to 3.5 mg given on D1 and on D4 every other week. Antitumor effects short of confirmed partial responses were observed in patients with melanoma, non–small-cell lung cancer, and renal cell carcinoma.ConclusionBortezomib (PS-341) is a novel antineoplastic agent that is well tolerated at doses not exceeding 3.0 mg (equivalent to 1.75 mg/m2), repeated on D1 and D4 every other week. This dose correlates with 70% inhibition of 20S proteasome activity. DLTs include neuropathy, fatigue, and diarrhea.
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Affiliation(s)
- A L Hamilton
- New York University School of Medicine, New York, NY, USA
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Khodel VA, Clark JW, Takano M, Zverev MV. Phase transitions in nucleonic matter and neutron-star cooling. Phys Rev Lett 2004; 93:151101. [PMID: 15524862 DOI: 10.1103/physrevlett.93.151101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2004] [Indexed: 05/24/2023]
Abstract
A new scenario for neutron-star cooling is suggested by the correspondence between pion condensation, induced by critical spin-isospin fluctuations, and the metal-insulator phase transition in a 2D electron gas. Above the threshold density for pion condensation, the neutron single-particle spectrum acquires an insulating gap that quenches neutron contributions to neutrino production. In the liquid phase just below the transition, the fluctuations play dual roles by (i) creating a multisheeted neutron Fermi surface that extends to low momenta and activates the normally forbidden direct Urca cooling mechanism, and (ii) amplifying the nodeless P-wave neutron superfluid gap while suppressing S-wave pairing. Lighter stars without a pion-condensed core undergo slow cooling, whereas enhanced cooling occurs in heavier stars via direct Urca emission from a thin shell of the interior.
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Affiliation(s)
- V A Khodel
- Russian Research Centre Kurchatov Institute, Moscow 123182, Russia
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24
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Dellen BK, Clark JW, Wessel R. Motion-contrast computation without directionally selective motion sensors. Phys Rev E Stat Nonlin Soft Matter Phys 2004; 70:031907. [PMID: 15524549 DOI: 10.1103/physreve.70.031907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2004] [Revised: 05/06/2004] [Indexed: 05/24/2023]
Abstract
The detection of relative motion, i.e., motion contrast, has been reported for motion-sensitive neurons in several vertebrate systems, yet the mechanism underlying motion-contrast sensitivity remains unknown. An algorithm for computing motion contrast directly from the moving intensity distribution is proposed. In this algorithm, the time-dependent intensity distribution of the visual space is convolved with a periodic function. For coherent motion, the resulting convolution integral reduces to a traveling wave of fixed amplitude, while incoherent motion causes the amplitude to oscillate. The frequency of the amplitude oscillation provides a measure of motion contrast. The algorithm is successful in reproducing tuning curves derived from measurements of motion-contrast sensitivity in avian tectum and primate middle temporal area.
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Affiliation(s)
- B K Dellen
- Department of Physics, Washington University, Saint Louis, Missouri 63130, USA
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25
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Lu K, Clark JW, Ghorbel FH, Robertson CS, Ware DL, Zwischenberger JB, Bidani A. Cerebral autoregulation and gas exchange studied using a human cardiopulmonary model. Am J Physiol Heart Circ Physiol 2004; 286:H584-601. [PMID: 12946929 DOI: 10.1152/ajpheart.00594.2003] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The goal of this work is to study the cerebral autoregulation, brain gas exchange, and their interaction by means of a mathematical model. We have previously developed a model of the human cardiopulmonary (CP) system, which included the whole body circulatory system, lung and peripheral tissue gas exchange, and the central nervous system control of arterial pressure and ventilation. In this study, we added a more detailed description of cerebral circulation, cerebrospinal fluid (CSF) dynamics, brain gas exchange, and cerebral blood flow (CBF) autoregulation. Two CBF regulatory mechanisms are included: autoregulation and CO(2) reactivity. Central chemoreceptor control of ventilation is also included. We first established nominal operating conditions for the cerebral model in an open-loop configuration using data generated by the CP model as inputs. The cerebral model was then integrated into the larger CP model to form a new integrated CP model, which was subsequently used to study cerebral hemodynamic and gas exchange responses to test protocols commonly used in the assessment of CBF autoregulation (e.g., carotid artery compression and the thigh-cuff deflation test). The model can closely mimic the experimental findings and provide biophysically based insights into the dynamics of cerebral autoregulation and brain tissue gas exchange as well as the mechanisms of their interaction during test protocols, which are aimed at assessing the degree of autoregulation. With further refinement, our CP model may be used on measured data associated with the clinical evaluation of the cerebral autoregulation and brain oxygenation in patients.
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Affiliation(s)
- K Lu
- Dynamical Systems Group, Rice University, Houston, TX 77005, USA
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26
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Abstract
We extend the hypothesis that neuronal populations represent and process analog variables in terms of probability density functions (PDFs). Aided by an intermediate representation of the probability density based on orthogonal functions spanning an underlying low-dimensional function space, it is shown how neural circuits may be generated from Bayesian belief networks. The ideas and the formalism of this PDF approach are illustrated and tested with several elementary examples, and in particular through a problem in which model-driven top-down information flow influences the processing of bottom-up sensory input.
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Affiliation(s)
- M J Barber
- Universidade da Madeira, Centro de Ciências Matemáticas, Campus Universitário da Penteada, 9000-390 Funchal, Portugal.
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Kürten KE, Clark JW. Higher-order neural networks, Polyà polynomials, and Fermi cluster diagrams. Phys Rev E Stat Nonlin Soft Matter Phys 2003; 68:037701. [PMID: 14524933 DOI: 10.1103/physreve.68.037701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2003] [Indexed: 05/24/2023]
Abstract
The problem of controlling higher-order interactions in neural networks is addressed with techniques commonly applied in the cluster analysis of quantum many-particle systems. For multineuron synaptic weights chosen according to a straightforward extension of the standard Hebbian learning rule, we show that higher-order contributions to the stimulus felt by a given neuron can be readily evaluated via Polyà's combinatoric group-theoretical approach or equivalently by exploiting a precise formal analogy with fermion diagrammatics.
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Affiliation(s)
- K E Kürten
- Institut für Experimentalphysik, Universität Wien, Austria
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28
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Abstract
It has been proposed that populations of neurons process information in terms of probability density functions (PDFs) of analog variables. Such analog variables range, for example, from target luminance and depth on the sensory interface to eye position and joint angles on the motor output side. The requirement that analog variables must be processed leads inevitably to a probabilistic description, while the limited precision and lifetime of the neuronal processing units lead naturally to a population representation of information. We show how a time-dependent probability densityρ(x; t) over variable x, residing in a specified function space of dimension D, may be decoded from the neuronal activities in a population as a linear combination of certain decoding functions φi(x), with coefficients given by the N firing rates ai(t) (generally with D ≪ N). We show how the neuronal encoding process may be described by projecting a set of complementary encoding functions [Formula: see text]i(x) on the probability density ρ(x; t), and passing the result through a rectifying nonlinear activation function. We show how both encoders [Formula: see text]i (x) and decoders φi(x) may be determined by minimizing cost functions that quantify the inaccuracy of the representation. Expressing a given computation in terms of manipulation and transformation of probabilities, we show how this representation leads to a neural circuit that can carry out the required computation within a consistent Bayesian framework, with the synaptic weights being explicitly generated in terms of encoders, decoders, conditional probabilities, and priors.
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Affiliation(s)
- M J Barber
- Institut für Theoretische Physik, Universität zu Köln, D-50937 Köln, Germany
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29
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Ramanathan RK, Clark JW, Kemeny NE, Lenz HJ, Gococo KO, Haller DG, Mitchell EP, Kardinal CG. Safety and toxicity analysis of oxaliplatin combined with fluorouracil or as a single agent in patients with previously treated advanced colorectal cancer. J Clin Oncol 2003; 21:2904-11. [PMID: 12885808 DOI: 10.1200/jco.2003.11.045] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PURPOSE Two consecutive compassionate use studies of oxaliplatin were conducted in the United States and Canada in more than 5000 patients with locally advanced or metastatic colorectal carcinoma who had experienced treatment failure after at least one prior chemotherapy regimen. PATIENTS AND METHODS The main focus was safety. Patients were assigned to treatment with either single-agent oxaliplatin or oxaliplatin in combination with fluorouracil (FU) and with or without leucovorin (LV) in various regimens. Response data collection was not a trial objective, but time to treatment failure (TTF) was recorded in the first cohort (1370 patients). RESULTS All treatment regimens were well tolerated, with an overall incidence of grade 3 or 4 hematologic toxicity of 23.2%, grade 3 or 4 treatment-related gastrointestinal toxicity of 26.4% (including diarrhea, vomiting, and mucositis), and grade 3 neurosensory toxicity 3.9%. Similar results were reported in the second cohort (3806 patients), in which the eligibility criteria were much less restrictive. In the first cohort (in which 83% received prior irinotecan), median TTF was 14 weeks, and was similar for the five regimens combining oxaliplatin and FU with or without LV, but significantly shorter for the single-agent oxaliplatin arm. The overall dose-intensity of oxaliplatin was maintained at 85.5% (range, 80.6% to 94.3%) of that prescribed by protocol (average 36.7 mg/m2/wk). CONCLUSION These data in a heavily pretreated patient population confirm that oxaliplatin is safe when used as a single agent or with a variety of FU-based regimens as salvage therapy in patients with advanced colorectal cancer.
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Qian J, Clark JW, Wang D, Kun L, Ghorbel F, Zwischenberger JB, Bidani A. TESTING THE PARA-CORPOREAL ARTIFICIAL LUNG USING COMPUTER MODELS. ASAIO J 2003. [DOI: 10.1097/00002480-200303000-00105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Abstract
Previous models combining the human cardiovascular and pulmonary systems have not addressed their strong dynamic interaction. They are primarily cardiovascular or pulmonary in their orientation and do not permit a full exploration of how the combined cardiopulmonary system responds to large amplitude forcing (e.g., by the Valsalva maneuver). To address this issue, we developed a new model that represents the important components of the cardiopulmonary system and their coupled interaction. Included in the model are descriptions of atrial and ventricular mechanics, hemodynamics of the systemic and pulmonic circulations, baroreflex control of arterial pressure, airway and lung mechanics, and gas transport at the alveolar-capillary membrane. Parameters of this combined model were adjusted to fit nominal data, yielding accurate and realistic pressure, volume, and flow waveforms. With the same set of parameters, the nominal model predicted the hemodynamic responses to the markedly increased intrathoracic (pleural) pressures during the Valsalva maneuver. In summary, this model accurately represents the cardiopulmonary system and can explain how the heart, lung, and autonomic tone interact during the Valsalva maneuver. It is likely that with further refinement it could describe various physiological states and help investigators to better understand the biophysics of cardiopulmonary disease.
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Affiliation(s)
- K Lu
- Dynamical Systems Group, Rice University, Houston Texas 77005, USA
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Abstract
BACKGROUND Investigators have to obtain informed consent before enrolling participants in clinical trials. We wanted to measure the quality of understanding among participants in clinical trials of cancer therapies, to identify correlates of increased understanding, and to assess providers' beliefs about clinical research. We also sought evidence of therapeutic misconceptions in participants and providers. METHODS We sent a standard questionnaire to 287 adult patients with cancer who had recently enrolled in a clinical trial at one of three affiliated institutions, and surveyed the provider who obtained each patient's consent. FINDINGS 207 of 287 (72%) patients responded. 90% (186) of these respondents were satisfied with the informed consent process and most considered themselves to be well informed. Nevertheless, many did not recognise non-standard treatment (74%), the potential for incremental risk from participation (63%), the unproven nature of the treatment (70%), the uncertainty of benefits to self (29%), or that trials are done mainly to benefit future patients (25%). In multivariate analysis, increased knowledge was associated with college education, speaking only English at home, use of the US National Cancer Institute consent form template, not signing the consent form at initial discussion, presence of a nurse, and careful reading of the consent form. Only 28 of 61 providers (46%) recognised that the main reason for clinical trials is benefit to future patients. INTERPRETATION Misconceptions about cancer clinical trials are frequent among trial participants, and physician/investigators might share some of these misconceptions. Efforts to educate providers and participants about the underlying goals of clinical trials are needed.
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Affiliation(s)
- S Joffe
- Department of Paediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
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Bunnell CA, Supko JG, Eder JP, Clark JW, Lynch TJ, Kufe DW, Shulman LN. Phase I clinical trial of 7-cyanoquinocarcinol (DX-52-1) in adult patients with refractory solid malignancies. Cancer Chemother Pharmacol 2001; 48:347-55. [PMID: 11761451 DOI: 10.1007/s002800100319] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE A phase I study of the antitumor antibiotic 7-cyanoquinocarcinol, DX-52-1, was conducted in patients with refractory solid malignancies. This study sought to determine the maximum tolerated dose and principal toxicities of this agent and to characterize its pharmacokinetic behavior. METHODS Patients were required to have adequate bone marrow, renal and hepatic function. DX-52-1 was administered by i.v. continuous infusion over a 6-h period each week for four consecutive weeks followed by a 2-week rest period, which constituted one cycle of treatment. RESULTS Initial dose levels were 3, 6, and 10 mg/m2. An intermediate dose level of 8 mg/m2 was added after acceptable toxicity was observed at the 6 mg/m2 dose level, but dose-limiting toxicities, including life-threatening ones, were seen at the 10 mg/m2 dose level in all three patients. The maximum tolerated dose (MTD) was subsequently determined to be 6 mg/m2. Because a clear pattern of toxicities was not initially evident, a larger than usual number of additional patients (16) were enrolled at the MTD to better distinguish toxicities due to the study drug from those secondary to the patients' underlying malignancies. Even at the MTD, the drug was poorly tolerated, with gastrointestinal toxicities (abdominal pain, nausea, vomiting and increased liver function tests) predominating and dose-limiting. Pharmacokinetic studies revealed that the mean maximum plasma concentration of DX-52-1 in patients evaluated at the MTD (138.8 +/- 59.3 ng/ml, n = 19) was considerably lower than the concentrations required for cytostatic or cytotoxic activity against sensitive human tumor cell lines in vitro. Further, the weekly dose intensity of the most efficacious treatment schedule identified during in vivo antitumor efficacy studies was 60 times greater than the 6 mg/m2 weekly dose tolerated by cancer patients. None of the 33 patients participating in this study, including the 22 patients evaluated at the MTD, had any response to treatment. CONCLUSION Given the poor tolerability, the inability to achieve drug levels necessary to inhibit in vitro or in vivo tumor growth, and the lack of any responses in our study, DX-52-1, as given by this schedule, does not appear to warrant further investigation in phase II studies.
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Affiliation(s)
- C A Bunnell
- Dana-Farber Cancer Institute and Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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McMahon PM, Halpern EF, Fernandez-del Castillo C, Clark JW, Gazelle GS. Pancreatic cancer: cost-effectiveness of imaging technologies for assessing resectability. Radiology 2001; 221:93-106. [PMID: 11568326 DOI: 10.1148/radiol.2211001656] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
PURPOSE To evaluate the cost-effectiveness of imaging strategies for the assessment of resectability in patients with pancreatic cancer. MATERIALS AND METHODS A decision model was developed to calculate costs and benefits (survival) accruing to hypothetical cohorts of patients with known or suspected pancreatic cancer. Results are presented as cost per life-year gained under various scenarios and assumptions of diagnostic test characteristics, surgical mortality, disease characteristics, and costs. RESULTS With best estimates for all data inputs, the strategy of computed tomography (CT) followed by laparoscopy and laparoscopic ultrasonography (US) had an incremental cost-effectiveness ratio of $87,502 per life-year gained, compared with best supportive care. This strategy was significantly more cost-effective than CT followed by magnetic resonance (MR) imaging and was significantly less expensive than other imaging strategies while providing a statistically and clinically insignificant difference in life-year gains. A strategy involving no imaging (immediate surgery) was more expensive but less effective than all imaging strategies. A hypothetical perfect test with cost equal to that of CT followed by MR had an incremental cost-effectiveness ratio of $64,401 per life-year gained, compared to best supportive care. CONCLUSION Most available imaging tests for assessing resectability of pancreatic cancer do not differ in effectiveness, but a strategy of CT, laparoscopy, and laparoscopic US would consistently result in significantly lower costs than other imaging tests under a wide range of scenarios.
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Affiliation(s)
- P M McMahon
- Decision Analysis and Technology Assessment Group, Department of Radiology, Massachusetts General Hospital, Zero Emerson Pl, Suite 2H, Boston, MA 02114, USA
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Sunita Rao D, Balkundi D, Uskokovic MR, Tserng K, Clark JW, Horst RL, Satyanarayana Reddy G. Double bond in the side chain of 1alpha,25-dihydroxy-22-ene-vitamin D(3) is reduced during its metabolism: studies in chronic myeloid leukemia (RWLeu-4) cells and rat kidney. J Steroid Biochem Mol Biol 2001; 78:167-76. [PMID: 11566441 DOI: 10.1016/s0960-0760(01)00082-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
1alpha,25-Dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)] is mainly metabolized via the C-24 oxidation pathway and undergoes several side chain modifications which include C-24 hydroxylation, C-24 ketonization, C-23 hydroxylation and side chain cleavage between C-23 and C-24 to form the final product, calcitroic acid. In a recent study we reported that 1alpha,25-dihydroxyvitamin D(2) [1alpha,25(OH)(2)D(2)] like 1alpha,25(OH)(2)D(3), is also converted into the same final product, calcitroic acid. This finding indicated that 1alpha,25(OH)(2)D(2) also undergoes side chain cleavage between C-23 and C-24. As the side chain of 1alpha,25(OH)(2)D(2) when compared to the side chain of 1alpha,25(OH)(2)D(3), has a double bond between C-22 and C-23 and an extra methyl group at C-24 position, it opens the possibility for both (a) double bond reduction and (b) demethylation to occur during the metabolism of 1alpha,25(OH)(2)D(2). We undertook the present study to establish firmly the possibility of double bond reduction in the metabolism of vitamin D(2) related compounds. We compared the metabolism of 1alpha,25-dihydroxy-22-ene-vitamin D(3) [1alpha,25(OH)(2)-22-ene-D(3)], a synthetic vitamin D analog whose side chain differs from that of 1alpha,25(OH)(2)D(3) only through a single modification namely the presence of a double bond between C-22 and C-23. Metabolism studies were performed in the chronic myeloid leukemic cell line (RWLeu-4) and in the isolated perfused rat kidney. Our results indicate that both 1alpha,25(OH)(2)-22-ene-D(3) and 1alpha,25(OH)(2)D(3) are converted into common metabolites namely, 1alpha,24(R),25-trihydroxyvitamin D(3) [1alpha,24(R),25(OH)(3)D(3)], 1alpha,25-dihydroxy-24-oxovitamin D(3) [1alpha,25(OH)(2)-24-oxo-D(3)], 1alpha,23(S),25-trihydroxy-24-oxovitamin D(3) and 1alpha,23-dihydroxy-24,25,26,27-tetranorvitamin D(3). This finding indicates that the double bond in the side chain of 1alpha,25(OH)(2)-22-ene-D(3) is reduced during its metabolism. Along with the aforementioned metabolites, 1alpha,25(OH)(2)-22-ene-D(3) is also converted into two additional metabolites namely, 1alpha,24,25(OH)(3)-22-ene-D(3) and 1alpha,25(OH)(2)-24-oxo-22-ene-D(3). Furthermore, we did not observe direct conversion of 1alpha,25(OH)(2)-22-ene-D(3) into 1alpha,25(OH)(2)D(3). These findings indicate that 1alpha,25(OH)(2)-22-ene-D(3) is first converted into 1alpha,24,25(OH)(3)-22-ene-D(3) and 1alpha,25(OH)(2)-24-oxo-22-ene-D(3). Then the double bonds in the side chains of 1alpha,24,25(OH)(3)-22-ene-D(3) and 1alpha,25(OH)(2)-24-oxo-22-ene-D(3) undergo reduction to form 1alpha,24(R),25(OH)(3)D(3) and 1alpha,25(OH)(2)-24-oxo-D(3), respectively. Thus, our study indicates that the double bond in 1alpha,25(OH)(2)-22-ene-D(3) is reduced during its metabolism. Furthermore, it appears that the double bond reduction occurs only during the second or the third step of 1alpha,25(OH)(2)-22-ene-D(3) metabolism indicating that prior C-24 hydroxylation of 1alpha,25(OH)(2)-22-ene-D(3) is required for the double bond reduction to occur.
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Affiliation(s)
- D Sunita Rao
- Department of Pediatrics, Women and Infants' Hospital of Rhode Island, Brown University School of Medicine, 101 Dudley Street, Providence, RI 02905, USA
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Khodel VA, Clark JW, Zverev MV. Superfluid phase transitions in dense neutron matter. Phys Rev Lett 2001; 87:031103. [PMID: 11461549 DOI: 10.1103/physrevlett.87.031103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2001] [Indexed: 05/23/2023]
Abstract
The phase transitions in a realistic system with triplet pairing, dense neutron matter, have been investigated. The spectrum of phases of the 3P2-3F2 model, which adequately describes pairing in this system, is analytically constructed with the aid of a separation method for solving BCS gap equations in states of arbitrary angular momentum. In addition to solutions involving a single value of the magnetic quantum number (and its negative), there exist ten real multicomponent solutions. Five of the corresponding angle-dependent order parameters have nodes, and five do not. In contrast to the case of superfluid 3He, transitions occur between phases with nodeless order parameters.
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Affiliation(s)
- V A Khodel
- McDonnell Center for the Space Sciences and Department of Physics, Washington University, St. Louis, Missouri 63130, USA
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37
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Abstract
We agree with almost all of the analysis in this excellent presentation of the molecular view of avoidance behavior. A few suggestions are made as follows: Referring to response-generated stimuli as ''readily observable" seems not quite right for the kinesthetic components of such stimuli, although their scientific legitimacy is not questioned. Interpreting response-generated stimuli as a form of positive reinforcement is contested, and an alternative interpretation is offered. A possibly simpler interpretation of the Sidman (1962) two-lever experiment is suggested. We question Dinsmoor's (2001) explanation for warning stimuli not being avoided, except for the reference to the weakness of third-order conditioning effects. A final question is raised regarding the nature of the variables that are responsible for the momentary evocation of the avoidance response.
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Affiliation(s)
- J Michael
- Psychology Department, Western Michigan University, Kalamazoo 49008, USA.
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Supko JG, Lynch TJ, Clark JW, Fram R, Allen LF, Velagapudi R, Kufe DW, Eder JP. A phase I clinical and pharmacokinetic study of the dolastatin analogue cemadotin administered as a 5-day continuous intravenous infusion. Cancer Chemother Pharmacol 2001; 46:319-28. [PMID: 11052630 DOI: 10.1007/s002800000152] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
PURPOSE The dolastatins are a class of naturally occurring cytotoxic peptides which function by inhibiting microtubule assembly and tubulin polymerization. Cemadotin is a synthetic analogue of dolastatin 15 with potent antiproliferative and preclinical antitumor activity. This report describes a phase I study to evaluate the administration of cemadotin to adult cancer patients by a 5-day continuous intravenous (CIV) infusion. METHODS All patients had histologically confirmed refractory solid tumors. The dose was escalated from an initial level of 2.5 mg/m2 (0.5 mg/m2 daily) according to a modified Fibonacci algorithm. A minimum of three patients was evaluated at each dose level until the maximum tolerated dose (MTD) was established. Treatment was repeated every 21 days until patients were removed from the study due to toxicity or disease progression. Drug-related toxicities were evaluated and graded by the U.S. National Cancer Institute's Common Toxicity Criteria. A radioimmunoassay (RIA) that detected both the parent drug and its metabolites with an intact N-terminal region of the molecule was used for pharmacokinetic studies. RESULTS Twenty heavily pretreated patients received a total of 40 courses of cemadotin over five dose levels ranging from 2.5 to 17.5 mg/m2. Reversible dose-related neutropenia was the principal dose-limiting toxicity and 12.5 mg/m2 was established as the MTD. Nonhematologic toxicities attributed to the drug were moderate, and there was no evidence of the cardiovascular toxicity noted in the prior phase I studies of cemadotin given IV as a 5-min injection or 24-h infusion. There were no objective antitumor responses. Time courses of the cemadotin RIA equivalent concentration in whole blood were defined in 14 patients during the first cycle of therapy. The RIA-detectable species exhibited apparent first-order pharmacokinetics across the entire range of doses. The mean +/- SD of the observed steady-state blood concentration at the 12.5 mg/m2 MTD was 282 +/- 7 nM (n = 3). Blood levels decayed monoexponentially following the end of the infusion, with a mean half-life of 13.2 +/- 4.3 h (n = 14) in all patients. Mean values (n = 14) of the total blood clearance and apparent volume of distribution at steady state were 0.52 +/- 0.09 lh/m2 and 9.9 +/- 3.3 l/m2, respectively. CONCLUSIONS The cardiotoxic effects of cemadotin were completely avoided by administering it as a 120-h CIV infusion. Thus. cardiovascular toxicity appears to be associated with the magnitude of the peak blood levels of the parent drug or its metabolites, whereas myelotoxicity is related to the duration of time that blood levels exceed a threshold concentration. Nevertheless, the data acquired during the extensive clinical experience with cemadotin requires careful examination to assess whether advancing this compound into disease-oriented efficacy studies is merited.
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Affiliation(s)
- J G Supko
- Division of Adult Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
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Clark JW, Hossain S, Burnside CA, Kambhampati S. Coevolution between a cockroach and its bacterial endosymbiont: a biogeographical perspective. Proc Biol Sci 2001; 268:393-8. [PMID: 11270436 PMCID: PMC1088619 DOI: 10.1098/rspb.2000.1390] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Cryptocercus are subsocial, xylophagous cockroaches that live in temperate forests. Like other cockroaches, Cryptocercus harbour endosymbiotic bacteria in their fat bodies. Two species of Cryptocercus occur in the palaearctic, one each in eastern Russia and south-central China. In the USA, there are five species: one in the north-west and four in the south-east. Little is known about the relationship between the Eurasian and North American Cryptocercus or the causes of the disjunct distribution. Here, a molecular phylogeny for six out of the seven Cryptocercus species and their endosymbionts is inferred in an attempt to understand the evolution and biogeography of the genus. Our analysis showed that the North American Cryptocercus are monophyletic, suggesting that a single colonization event was followed by vicariance. There was complete concordance between the host and endosymbiont phylogenetic trees. Divergence estimates based on endosymbiont DNA sequences suggested that the palaearctic and nearctic Cryptocercus diverged 70-115 million years (Myr) ago and the eastern- and western-USA species diverged 53-88 Myr ago. These divergence estimates were correlated with biogeographical events, and a hypothesis is presented to explain the current distribution of Cryptocercus. Our findings suggest that Cryptocercus has had a long evolutionary history, dating back to the Jurassic.
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Affiliation(s)
- J W Clark
- Department of Entomology, Kansas State University, Manhattan 66506, USA
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Ryan DP, Supko JG, Eder JP, Seiden MV, Demetri G, Lynch TJ, Fischman AJ, Davis J, Jimeno J, Clark JW. Phase I and pharmacokinetic study of ecteinascidin 743 administered as a 72-hour continuous intravenous infusion in patients with solid malignancies. Clin Cancer Res 2001; 7:231-42. [PMID: 11234874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Ecteinascidin 743 (ET-743) is a cytotoxic tetrahydroisoquinoline alkaloid that covalently binds to DNA in the minor groove. The in vitro chemosensitivity of cancer cells to ET-743 is markedly enhanced by prolonging the duration of exposure to the drug. A Phase I study of ET-743 given as a 72-h continuous i.v. infusion every 21 days was performed. Characteristics of the 21 adult patients with refractory solid tumors enrolled in the study were as follows: (a) 12 men; (b) 9 women; (c) median age, 59 years; (d) Eastern Cooperative Oncology Group performance status < or = 1, 20 patients; and (e) two prior regimens of chemotherapy, 7 patients. Dose limiting toxicity (DLT) was defined by typical criteria, except that grade 3 transaminitis did not constitute a DLT. There were no DLTs in the six patients evaluated at the first two dose levels of 600 and 900 microg/m2. Reversible grade 4 transaminitis occurred in two of nine patients after treatment with the first cycle of therapy at the third dose level of 1200 microg/m2. Another patient experienced grade 4 rhabdomyolysis, renal failure requiring hemodialysis, grade 4 neutropenia, and grade 3 thrombocytopenia during the second cycle of therapy with this dose. The maximum tolerated dose was 1200 microg/m2, and an additional six patients were enrolled at an intermediate dose level of 1050 microg/m2. This well-tolerated dose was established as the recommended Phase II dose. The disposition of ET-743 was distinctly biexponential, and a departure from linear pharmacokinetic behavior was evident at the 1200-microg/m2 dose level. Pharmacokinetic parameters determined at 1050 microg/m2 were (mean +/- SD): maximum plasma concentration, 318 +/- 147 pg/ml; initial disposition phase half-life, 9.0 +/- 10.3 min; terminal phase half-life, 69.0 +/- 56.7 h; and total plasma clearance, 28.4 +/- 22.5 liters/h/m2. Prolonged systemic exposure to concentrations of the agent that are cytotoxic in vitro were achieved. Toxicity of the drug is clearly schedule-dependent, because increasing the duration of infusion from 3 or 24 h to 72 h results in decreased myelosuppression and comparable hepatotoxicity. Although there were no objective responses to therapy, clear evidence of antitumor activity was observed in a patient with epithelioid mesothelioma, as confirmed by positron emission tomography studies. A Phase II trial to assess the efficacy of ET-743 against this highly refractory neoplasm has been initiated on the basis of this observation. The therapeutically optimal administration schedule remains to be established, inasmuch as there have been indications of activity against a variety of tumors during Phase I studies when the drug was infused over times ranging from 1 to 72 h. Characterizing the pharmacokinetics of ET-743 during the course of Phase II trials and Phase I combination studies is recommended to assure that this promising new anticancer drug can be used with an acceptable margin of safety.
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Affiliation(s)
- D P Ryan
- Massachusetts General Hospital, Boston, Massachusetts 02114, USA.
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Abstract
BACKGROUND The informed consent of participants is ethically and legally required for most research involving human subjects. However, standardized methods for assessing the adequacy of informed consent to research are lacking. METHODS AND RESULTS We designed a brief questionnaire, the Quality of Informed Consent (QuIC), to measure subjects' actual (objective) and perceived (subjective) understanding of cancer clinical trials. The QuIC incorporates the basic elements of informed consent specified in federal regulations, assesses the therapeutic misconception (the belief that all aspects of a clinical trial are designed to directly benefit the subject), and employs the language and structure of the new National Cancer Institute template for informed consent documents. We modified the QuIC after receiving feedback from pilot tests with cancer research subjects, as well as validation from two independent expert panels. We then sent the QuIC to 287 adult cancer patients enrolled on phase I, II, or III clinical trials. Two hundred seven subjects (72%) completed the QuIC. To assess test-retest reliability, a random sample of 32 respondents was selected, of whom 17 (53%) completed the questionnaire a second time. The test-retest reliability was good with intraclass correlation coefficients of.66 for tests of objective understanding and.77 for tests of subjective understanding. The current version of the QuIC, which consists of 20 questions for objective understanding and 14 questions for subjective understanding, was tested for time and ease of administration in a sample of nine adult cancer patients. The QuIC required an average of 7.2 minutes to complete. CONCLUSIONS The QuIC is a brief, reliable, and valid questionnaire that holds promise as a standardized way to assess the outcome of the informed consent process in cancer clinical trials.
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Affiliation(s)
- S Joffe
- Department of Pediatrics, Dana-Farber Cancer Institute, and Division of Hematology/Oncology, Children's Hospital, Boston, USA
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Abstract
1. We have developed a mathematical model of the L-type Ca2+ current, which is based on data from whole-cell voltage clamp experiments on rat ventricular myocytes. Ion substitution methods were employed to investigate the ionic selectivity of the channel. Experiments were configured with Na+, Ca2+ or Ba2+ as the majority current carrier. 2. The amplitude of current through the channel is attenuated in the presence of extracellular Ca2+ or Ba2+. Our model accounts for channel selectivity by using a modified Goldman-Hodgkin-Katz (GHK) configuration that employs voltage-dependent channel binding functions for external divalent ions. Stronger binding functions were used for Ca2+ than for Ba2+. 3. Decay of the ionic current during maintained depolarization was characterized by means of voltage- and Ca2+-dependent inactivation pathways embedded in a five-state dynamic channel model. Particularly, Ca2+ first binds to calmodulin and the Ca2+-calmodulin complex is the mediator of Ca2+ inactivation. Ba2+-dependent inactivation was characterized using the ttau same scheme, but with a decreased binding to calmodulin. 4. A reduced amount of steady-state inactivation, as evidenced by a U-shaped curve at higher depolarization levels (>40 mV) in the presence of [Ca2+]o, was observed in double-pulse protocols used to study channel inactivation. To characterize this phenomenon, a mechanism was incorporated into the model whereby Ca2+ or Ba2+ also inhibits the voltage-dependent inactivation pathway. 5. The five-state dynamic channel model was also used to simulate single channel activity. Calculations of the open probability of the channel model are generally consistent with experimental data. A sixth state can be used to simulate modal activity by way of introducing long silent intervals. 6. Our model has been tested extensively using experimental data from a wide variety of voltage clamp protocols and bathing solution manipulations. It provides: (a) biophysically based explanations of putative mechanisms underlying Ca2+- and voltage-dependent channel inactivation, and (b) close fits to voltage clamp data. We conclude that the model can serve as a predictive tool in generating testable hypotheses for further investigation of this complex ion channel.
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Affiliation(s)
- L Sun
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005-1892, USA
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Abstract
Neurons of the mammalian medullary respiratory center have complex patterns of electrophysiological behavior. Three typical phenomena associated with these patterns are spike frequency adaptation (SFA), delayed excitation (DE), and postinhibitory rebound (PIR). Although several nuclei are associated with the medullary-pontine respiratory center, we focused on neurons from two nuclei: (1) the ventral subnucleus of the nucleus tractus solitarius (vNTS) of the dorsal respiratory group and (2) the nucleus ambiguus (NA) of the ventral respiratory group. We developed a Hodgkin-Huxley (HH) type model of the typical medullary neuron that is capable of mimicking the discharge pattern of real neurons to a very high degree. Closer examination of typical data revealed, however, that there was not one type of medullary respiratory neuron, but at least three (types A, B1, and B2). We classified these neurons based on the electrophysiologic phenomena that they exhibited (type A exhibits DE but not PIR; types B1 and B2 exhibit PIR but not DE; all types are adapting). Our objective was to relate each of these well-known phenomena to specific ionic current mechanisms. In the model, three currents directly affect the phenomena investigated: the Ca2+-activated K+ current, I(K,Ca), controls peak and steady-state firing rates and the time constant of adaptation; the transient outward K+ current, I(A), is responsible for all aspects of DE, including the dependence of delay on the magnitude and duration of conditioning hyperpolarization; and the hyperpolarization-activated current, Ih, elicits PIR and dictates its dependencies. We consider that our HH model represents a unifying structure, whereby different electrophysiological phenomena or discharge patterns can be emulated using different strengths of the component ionic membrane currents (particularly I(K,Ca), I(A), and Ih). Moreover, its predictions suggest that the electrophysiological characteristics of medullary respiratory neurons, from different areas of the brainstem and even from different species, can be modeled using the same structural framework, wherein the specific properties of individual neurons are emulated by adjusting the strengths of key ionic membrane currents in the model.
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Affiliation(s)
- A Athanasiades
- Dynamical Systems Group, School of Engineering, Rice University, Houston, TX 77005, USA
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Czito BG, Willett CG, Clark JW, Fernandez Del Castillo C. Current perspectives on locally advanced pancreatic cancer. Oncology (Williston Park) 2000; 14:1535-45; discussion 1546, 1549-52. [PMID: 11125940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
This year, approximately 40% of the 28,300 patients diagnosed with pancreatic carcinoma in the United States will present with locally advanced disease. Radiotherapeutic approaches are often employed, as these patients have unresectable tumors by virtue of local invasion into the retroperitoneal vessels in the absence of clinically detectable metastases. These treatments include external-beam irradiation with and without fluorouracil (5-FU)-based chemotherapy, intraoperative irradiation, and more recently, external-beam irradiation with new systemic agents, such as gemcitabine (Gemzar).
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Affiliation(s)
- B G Czito
- Massachusetts General Hospital, Boston, Massachusetts, USA
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45
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Olansen JB, Clark JW, Khoury D, Ghorbel F, Bidani A. A closed-loop model of the canine cardiovascular system that includes ventricular interaction. Comput Biomed Res 2000; 33:260-95. [PMID: 10944405 DOI: 10.1006/cbmr.2000.1543] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A closed-loop model of cardiopulmonary circulation has been developed for the study of right-left ventricular interaction under physiologically normal and altered conditions. The core model provides insight into the effects of ventricular interaction and pericardial mechanics on hemodynamics. The complete model contains realistic descriptions of (a) the interacting ventricular free walls and septum, (b) the atria, (c) the pericardium, and (d) the systemic and pulmonary vascular loads. The current analysis extends previous work on ventricular interaction and pericardial influence under isolated heart conditions to loading conditions imposed by a closed-loop model of the circulation. A nonlinear least-squares parameter identification method (Levenberg-Marquardt algorithm) is used, together with parameter sensitivity analysis, to estimate the values of key parameters associated with the ventricular and circulation models. Pressure measurements taken at several anatomical locations in the circulation during open-chest experiments on dogs are used as data in the identification process. The complete circulatory model, including septal and pericardial coupling, serves as a virtual testbed for assessing the global affects of localized mechanical or hemodynamic alterations. Studies of both direct and series ventricular interaction, as well as the effect of the pericardium on cardiac performance, are accomplished with this model. Alterations in model parameter values are used to predict the impact of disease and/or clinical interventions on steady-state hemodynamic performance. Additionally, a software package titled CardioPV has been developed to integrate the complete model with data acquisition tools and a sophisticated graphical user interface. The complete software package enables users to collect experimental data, use the data to estimate model parameters, and view the model outputs in an online setting.
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Affiliation(s)
- J B Olansen
- Dynamical Systems Group, Rice University, Houston, TX 77005, USA
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Clark JW. Biological response modifiers. Cancer Chemother Biol Response Modif 2000; 18:223-38. [PMID: 10800485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Affiliation(s)
- J W Clark
- M.G.H. Cancer Center, Boston, MA 02114, USA
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Voskresensky DN, Khodel VA, Zverev MV, Clark JW. Rearrangement of the Fermi Surface of Dense Neutron Matter and the Direct Urca Cooling of Neutron Stars. Astrophys J 2000; 533:L127-L130. [PMID: 10770706 DOI: 10.1086/312607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2000] [Accepted: 03/08/2000] [Indexed: 05/23/2023]
Abstract
It is proposed that a rearrangement of single-particle degrees of freedom may occur in a portion of the quantum-fluid interior of a neutron star. Such a rearrangement is associated with the pronounced softening of the spin-isospin collective mode which, under increasing density, leads to pion condensation. Arguments and estimates based on fundamental relations of many-body theory show that one realization of this phenomenon could produce very rapid cooling of the star via a direct nucleon Urca process displaying a T5 dependence on temperature.
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John W, Picus J, Blanke CD, Clark JW, Schulman LN, Rowinsky EK, Thornton DE, Loehrer PJ. Activity of multitargeted antifolate (pemetrexed disodium, LY231514) in patients with advanced colorectal carcinoma. Cancer 2000. [DOI: 10.1002/(sici)1097-0142(20000415)88:8<1807::aid-cncr8>3.0.co;2-l] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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John W, Picus J, Blanke CD, Clark JW, Schulman LN, Rowinsky EK, Thornton DE, Loehrer PJ. Activity of multitargeted antifolate (pemetrexed disodium, LY231514) in patients with advanced colorectal carcinoma: results from a phase II study. Cancer 2000; 88:1807-13. [PMID: 10760756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
BACKGROUND The aim of this study was to confirm the activity and assess the safety profile of multitargeted antifolate (MTA) for patients with metastatic colorectal adenocarcinoma. METHODS Forty-six patients were enrolled in the study, 35 with colon and 11 with rectal carcinoma. Adjuvant therapy was allowed if completed 1 year previously. Patients received MTA 600 mg/m(2) as a 10-minute intravenous infusion once every 21 days. Blood samples were taken every cycle for pharmacokinetic and vitamin metabolite assays. RESULTS Among 39 patients eligible for efficacy analysis, 1 complete response and 5 partial responses were identified, for an overall response rate of 15.4% (95% confidence interval [CI], 4.1-26. 7%) for all patients. Fifteen patients had stable disease, with 9 living longer than 1 year. The median survival was 16.2 months (95% CI, 10.5-17.0%); 65% of patients were alive at 1 year, and the median time to progression was 4.4 months (range, 3.2-5.7 months). The main toxicities were hematologic, with common toxicity criteria (CTC) Grades 3 or 4 noted as follows: thrombocytopenia (18%), neutropenia (55%), and anemia (18%). Nonhematologic toxicities included Grade 2 or 3 skin reaction (53%), ameliorated by dexamethasone, and Grade 3 transaminases (23%). Dose omissions were not required and 21% of doses were reduced. CONCLUSIONS MTA has clear activity in patients with colorectal carcinoma, and encouraging survival times were noted. MTA was well tolerated in this patient group, but myelosuppression was frequent. Toxicity may be increased with folate deficiency.
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Ryan DP, Lynch TJ, Grossbard ML, Seiden MV, Fuchs CS, Grenon N, Baccala P, Berg D, Finkelstein D, Mayer RJ, Clark JW. A phase I study of gemcitabine and docetaxel in patients with metastatic solid tumors. Cancer 2000; 88:180-5. [PMID: 10618622 DOI: 10.1002/(sici)1097-0142(20000101)88:1<180::aid-cncr25>3.3.co;2-h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND A Phase I study was initiated to determine the maximum tolerated dose of weekly gemcitabine combined with monthly, fixed-dose docetaxel. METHODS Patients with metastatic solid tumors were treated with docetaxel, 60 mg/m(2), on Day 1 every 28 days. Gemcitabine was administered on Days 1, 8, and 15 and underwent dose adjustment in cohorts of 3-6 patients. At the maximum tolerated dose, 11 additional patients were enrolled. RESULTS Twenty-six patients received 85 cycles of therapy. At the first dose level, the planned gemcitabine dose on Days 1, 8, and 15 was 800 mg/m(2). Two of the 6 patients treated at this dose level experienced dose-limiting toxicities (DLTs) requiring the reduction of gemcitabine to 600 mg/m(2) per dose and the administration of ciprofloxacin, 500 mg orally twice daily, on Days 8-18. At the second dose level the first 3 patients experienced no DLTs and the dose of gemcitabine was increased to 700 mg/m(2). Two of the 6 patients treated at the 700 mg/m(2) dose level experienced DLTs. Eleven additional patients were enrolled at the recommended Phase II dose of gemcitabine (600 mg/m(2)). At this dose level, Grade 3/4 (according the National Cancer Institute's common toxicity criteria) neutropenia and thrombocytopenia occurred in 12.5% and 2.1% of cycles, respectively. Grade 3 and 4 nonhematologic toxicities were uncommon. Three of seven evaluable patients with pancreatic carcinoma had evidence of significant antineoplastic activity (three partial responses). In addition, two complete responses (one patient with gastric carcinoma and one patient with ovarian carcinoma) and one partial response (patient with hepatocellular carcinoma) were noted in patients with other solid tumors. CONCLUSIONS The regimen comprised of docetaxel, 60 mg/m(2), on Day 1 and gemcitabine, 600 mg/m(2), on Days 1, 8, and 15 with ciprofloxacin on Days 8-18 every 28 days is safe, well tolerated, and active.
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Affiliation(s)
- D P Ryan
- Gastrointestinal Cancer Clinic, Dana-Farber/Partners CancerCare, Boston, Massachusetts, USA
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