Dynamics of overdose and non-overdose mortality among people living with HIV amidst the illicit drug toxicity crisis in British Columbia

We sought to characterize overdose and non-overdose mortality among PLWH amidst the illicit drug toxicity crisis in British Columbia, Canada. A population-based analysis of PLWH (age ≥19) in British Columbia accessing healthcare from April 1996 to March 2017 was conducted using data from the Seek and Treat for Optimal Prevention of HIV/AIDS (STOP HIV/AIDS) cohort linkage. Underlying causes of deaths were stratified into overdose and non-overdose causes. We compared (bivariate analysis) health-related characteristics and prescription history between PLWH died of overdose and non-overdose causes between April 2009 and March 2017. Among 9,180 PLWH, we observed 962 deaths (142 [14.7%] overdoses; 820 [85.2%] other causes). Compared to those who died from other causes, those who died of overdose were significantly younger (median age [Q, Q3]: 46 years [42, 52] vs. 54 years [48, 63]); had an indication of chronic pain (35.9% vs. 27.1%) and hepatitis C virus (64.8% vs. 50.4%), but fewer experienced hospitalization in the year before death. PLWH who died were most likely to be prescribed with opioids (>50%) and least likely with opioid agonist therapy (<10%) in a year before death. These findings highlight the syndemic of substance use, HCV, and chronic pain, and how the crisis is unqiuely impacting females and younger people.

SARS-CoV-2 seroprevalence among Vancouver public school staff in British Columbia, Canada: a cross-sectional study

OBJECTIVES

Few studies reported COVID-19 cases in schools during the 2020/21 academic year in a setting of uninterrupted in-person schooling. The main objective was to determine the SARS-CoV-2 seroprevalence among school staff in Vancouver public schools.

DESIGN

Cumulative incident COVID-19 cases among all students and school staff based on public health data, with an embedded cross-sectional serosurvey among a school staff sample that was compared to period, age, sex and geographical location-weighted data from blood donors.

SETTING

Vancouver School District (British Columbia, Canada) from kindergarten to grade 12.

PARTICIPANTS

Active school staff enrolled from 3 February to 23 April 2021 with serology testing from 10 February to 15 May 2021.

MAIN OUTCOME MEASURES

SARS-CoV-2 seroprevalence among school staff, based on spike (S)-based (unvaccinated staff) or N-based serology testing (vaccinated staff).

RESULTS

Public health data showed the cumulative incidence of COVID-19 among students attending in-person was 9.8 per 1000 students (n=47 280), and 13 per 1000 among school staff (n=7071). In a representative sample of 1689 school staff, 78.2% had classroom responsibilities, and spent a median of 17.6 hours in class per week (IQR: 5.0-25 hours). Although 21.5% (363/1686) of surveyed staff self-reported close contact with a COVID-19 case outside of their household (16.5% contacts were school-based), 5 cases likely acquired the infection at school based on viral testing. Sensitivity/Specificity-adjusted seroprevalence in 1556/1689 staff (92.1%) was 2.3% (95% CI: 1.6% to 3.2%), comparable to a sex, age, date and residency area-weighted seroprevalence of 2.6% (95% CI: 2.2% to 3.1%) among 5417 blood donors.

CONCLUSION

Seroprevalence among staff was comparable to a reference group of blood donors from the same community. These data show that in-person schooling could be safely maintained during the 2020/21 school year with mitigation measures, in a large school district in Vancouver, Canada.

SARS-CoV-2 transmission in kindergarten to grade 12 schools in the Vancouver Coastal Health region: a descriptive epidemiologic study

BACKGROUND

There is an urgent need to assess the role of schools in the spread of SARS-CoV-2 in Canada to inform public health measures. We describe the epidemiology of SARS-CoV-2 infection among students and staff in the Vancouver Coastal Health (VCH) region in the first 3 months of the 2020/2021 academic year, and examine the extent of transmission in schools.

METHODS

This descriptive epidemiologic study using contact tracing data included individuals aged 5 years and older with SARS-CoV-2 infection, reported between Sept. 10 and Dec. 18, 2020, who worked in or attended kindergarten to grade 12 (K-12) schools in person in the VCH region. We described case and cluster characteristics and reported the number of school-based transmissions.

RESULTS

During the study period, 699 cases of SARS-CoV-2 infection were reported (55 cases per 10 000 VCH school population). Among cases in VCH resident staff and students, 52.5% (354/674) were linked to a household case or cluster; less than 1.5% (< 10) of infected individuals were hospitalized and none died. Out of 699 cases present at school, 26 clusters with school-based transmission resulted in 55 secondary cases. Staff members accounted for 53.8% of index cases (14/26) while making up 14.3% of the school population (17 742/123 647). Among clusters, 88.5% (23) had fewer than 4 secondary cases.

INTERPRETATION

In our population during the study period, there were no deaths and severe disease was rare; furthermore, school-based SARS-CoV-2 transmissions were uncommon and clusters were small. Our results, which relate primarily to symptomatic disease, support the growing body of evidence that schools likely did not play a major role in SARS-CoV-2 spread in 2020.

SARS-CoV-2 transmission in kindergarten to grade 12 schools in the Vancouver Coastal Health region: a descriptive epidemiologic study

BACKGROUND

There is an urgent need to assess the role of schools in the spread of SARS-CoV-2 in Canada to inform public health measures. We describe the epidemiology of SARS-CoV-2 infection among students and staff in the Vancouver Coastal Health (VCH) region in the first 3 months of the 2020/2021 academic year, and examine the extent of transmission in schools.

METHODS

This descriptive epidemiologic study using contact tracing data included individuals aged 5 years and older with SARS-CoV-2 infection, reported between Sept. 10 and Dec. 18, 2020, who worked in or attended kindergarten to grade 12 (K-12) schools in person in the VCH region. We described case and cluster characteristics and reported the number of school-based transmissions.

RESULTS

During the study period, 699 cases of SARS-CoV-2 infection were reported (55 cases per 10 000 VCH school population). Among cases in VCH resident staff and students, 52.5% (354/674) were linked to a household case or cluster; less than 1.5% (< 10) of infected individuals were hospitalized and none died. Out of 699 cases present at school, 26 clusters with school-based transmission resulted in 55 secondary cases. Staff members accounted for 53.8% of index cases (14/26) while making up 14.3% of the school population (17 742/123 647). Among clusters, 88.5% (23) had fewer than 4 secondary cases.

INTERPRETATION

In our population during the study period, there were no deaths and severe disease was rare; furthermore, school-based SARS-CoV-2 transmissions were uncommon and clusters were small. Our results, which relate primarily to symptomatic disease, support the growing body of evidence that schools likely did not play a major role in SARS-CoV-2 spread in 2020.

Osteonecrosis in SLE: prevalence, patterns, outcomes and predictors

Objective Osteonecrosis is a serious comorbidity in patients with systemic lupus erythematosus. The aims of this study were to describe the prevalence of symptomatic osteonecrosis, determine the pattern of joint involvement, identify the outcomes and investigate predictive factors in a large cohort of patients with systemic lupus erythematosus followed prospectively. Methods At the Toronto Lupus Clinic patients have been followed prospectively according to a standard protocol since 1970. Osteonecrosis is recorded if patients are symptomatic and is confirmed by imaging. The site of osteonecrosis is recorded and whether or not surgery was performed. For determination of prevalence, pattern and outcome of osteonecrosis a longitudinal cohort design was performed. For the predictive factors, only patients with incident osteonecrosis were included and were matched for gender, year of entry to clinic (within 5 years), year of birth (within 5 years) and disease duration (within 3 years) with systemic lupus erythematosus patients without osteonecrosis. Results Of 1729 patients with systemic lupus erythematosus registered in the database, 234 (13.5%) developed symptomatic osteonecrosis in 581 sites. Hips and knees were most commonly affected and 47% of the patients had multiple sites involved. More than half of the joints involved at first occurrence of osteonecrosis had surgery. Univariate analysis identified black race, damage, elevated cholesterol and glucocorticosteroids as predictive factors, but glucocorticosteroids remained as the primary predictor for the development of osteonecrosis on multivariable analysis. Conclusion Despite advancements in the assessment and treatment of systemic lupus erythematosus, symptomatic osteonecrosis continues to be a significant comorbidity. Strategies to minimize glucocorticosteroid use are necessary to prevent this serious complication.

Characteristics and Evaluation of Geographically Distant vs Geographically Nearby Living Kidney Donors

BACKGROUND

Living donor kidney transplant (LDKT) can be impeded by multiple barriers. One possible barrier to LDKT is a large physical distance between the living donor's home residence and the procuring transplant center.

METHODS

We performed a retrospective, single-center study of living kidney donors in the United States who were geographically distant (residing ≥150 miles) from our transplant center. Each distant donor was matched to 4 geographically nearby donors (<150 miles from our center) as controls.

RESULTS

From 2007 to 2010, of 429 live kidney donors, 55 (12.8%) were geographically distant. Black donors composed a higher proportion of geographically distant vs nearby donors (34.6% vs 15.5%), whereas Hispanic and Asian donors composed a lower proportion (P = .001). Distant vs nearby donors had similar median times from donor referral to actual donation (165 vs 161 days, P = .81). The geographically distant donors lived a median of 703 miles (25% to 75% range, 244 to 1072) from our center and 21.2 miles (25% to 75% range, 9.8 to 49.7) from the nearest kidney transplant center. The proportion of geographically distant donors who had their physician evaluation (21.6%), psychosocial evaluation (21.6%), or computed tomography angiogram (29.4%) performed close to home, rather than at our center, was low.

CONCLUSIONS

Many geographically distant donors live close to transplant centers other than the procuring transplant center, but few of these donors perform parts of their donor evaluation at these closer centers. Black donors comprise a large proportion of geographically distant donors. The evaluation of geographically distant donors, especially among minorities, warrants further study.

Abstract P6-07-06: Clinicopathologic characterization and comprehensive genomic profiling (CGP) of advanced breast cancer patients with fibroblast growth factor receptor (FGFR) alterations

BACKGROUND: FGFR family members are infrequently mutated but are frequently overexpressed in breast cancer and often accompanied by increased, or altered, expression of FGF ligands. In this retrospective study, we reviewed a large series of FGFR altered breast cancer cases that received comprehensive genomic profiling (CGP) in the course of clinical care.

MATERIAL AND METHODS: CGP was performed on hybridization-captures, adaptor ligation-based libraries using DNA extracted from 40 μm formalin-fixed paraffin-embedded (FFPE) section cut at 10 μm performed in a CLIA-certified lab (Foundation Medicine, Inc.). The pathologic diagnosis of each case was confirmed on routine hematoxylin and eosin-stained slides, and all samples forwarded for DNA extraction contained a minimum of 20% of DNA derived from tumor cells. The FoundationOne test sequences the full coding regions of up to 315 cancer-related genes, and up to 28 genes that are frequently altered in cancer to detect all classes of genomic alterations including base substitutions, indels, copy-number alterations (CNA), and fusions/rearrangements. The average depth of coverage is greater than 600X. The genomic profiles of 2,617 patients with diverse advanced malignancies who were evaluated at Cancer Treatment Centers of America between 12/24/12 and 03/11/15 were reviewed. 176 FGFR alterations (7.8%) were detected, of which 76 (43.5%) were found in breast cancer cases out of 434 (16.5%). The study was carried out in accordance with WIRB Institutional Review Board.

RESULTS: A total of 76 female breast cancer patients, having a median age 50 (range, 28-69), with FGFR alterations were reviewed. All patients had metastatic/relapsed advanced breast cancer. 54 patients were Estrogen Receptor-positive (70%), and 15 were HER2+ (20%). 6 patients had gBRCA deleterious mutations. 84% of the samples (n=67) tissue block were analyzed, and the anatomic sites represented by the samples were 24 breast primary tumor (31%), 15 liver (19%), 10 lymph nodes (13%), and other sites (37%). The median number of chemotherapies cycles was 4 (range, 1-12), and the median time to metastasis was 31 months (range, 0-175). At the time of this report, 31 patients (40%) were deceased. 79 FGFR gene alterations were identified in 76 patients, including FGFR1 (65), FGFR2 (6), FGFR3 (2), and FGFR4 (4), with all but 7 of these being amplifications. The most co-existent altered gene was TP53 (66%), and other altered genes included PIK3CA (37%), MYC (28%), FGF3/4/19 (17%), CCND1 (17%), and CCNE1 (16%). The subset of co-amplified FGF3/4/19 and FGFR amplified patients were all (7) ER+ except for 1 patient.

CONCLUSIONS: FGFR genomic alterations in breast cancer patients are predominantly amplifications and are most commonly observed in ER+ patients. Further review of treatment history will be performed to evaluate the hypothesis that alterations of FGFR is a modifier of response to endocrine therapy, and co-amplified FGF3/4/19 and FGFR breast cancer cases may be a distinct clinic-pathologic entity. Any patients in this series initiated on anti-FGFR targeted therapy will also be reported.

Citation Format: Alvarez RH, Thomas JW, Kramer K, Niu J, Ahn E, McKnight JE, Dhillon N, Pabbathi H, Johnson AT, Wang K, Ross JS, Miller VA, Stephens PJ, Daneker GW, Ali S, Markman M. Clinicopathologic characterization and comprehensive genomic profiling (CGP) of advanced breast cancer patients with fibroblast growth factor receptor (FGFR) alterations. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-07-06.

Teaching fearlessness: a manifesto

CONTEXT

Negative role modeling is a plague medical educators fight once students enter the clinical arena. The literature is replete on the fact that students routinely encounter faculty who display attitudes and behaviors inconsistent with the values taught throughout the medical curriculum, particularly in the preclinical years.

APPROACH

Using a back and forth between the text of a third-year student's reflective essay and two of her faculty's observations on her negative encounters with several clinical faculty, the authors propose 'teaching for fearlessness.'

DISCUSSION

Using Papadimos and Murray's use of 'fearless speech' derived from Foucault's thinking on parrhesia, the authors build a case that students should be encouraged to expose and challenge inequities on behalf of their patients, themselves and the profession at large.

CONCLUSIONS

Medical educators should model and provide students with opportunities to develop and use 'fearless speech' as a way to reshape the culture of medical education and patient care.

Fractures and Fanconi syndrome due to prolonged sodium valproate use

BACKGROUND

Sodium valproate (VPA) is commonly used to treat epilepsy in children. Renal dysfunction is a rare side eff ect but can present as tubulopathy such as Fanconi syndrome.

CASE REPORT

We report on an 8-year-old disabled girl with myoclonic epilepsy who was referred for investigation of recurrent low impact fractures of the distal femur which were initially thought to be caused by her severe immobility. However, she was subsequently found to have hypophosphataemia secondary to Fanconi syndrome due to prolonged VPA use. After VPA withdrawal renal function and serum phosphate levels normalised and X-rays improved dramatically.

CONCLUSION

The possibility of drug-induced osteoporosis and fractures should always be considered in disabled children, even in the presence of severe immobility.

Immune reconstitution following rabbit antithymocyte globulin

Depletional induction therapies are routinely used to prevent acute rejection and improve transplant outcome. The effects of depleting agents on T-cell subsets and subsequent T-cell reconstitution are incompletely defined. We used flow cytometry to examine the effects of rabbit antithymocyte globulin (rATG) on the peripheral T-cell repertoire of pediatric and adult renal transplant recipients. We found that while rATG effectively depleted CD45RA+CD27+ naïve and CD45RO+CD27+ central memory CD4+ T cells, it had little effect on CD45RO+CD27- CD4+ effector memory or CD45RA+CD31-, CD45RO+CD27+ and CD45RO+CD27- CD8+ T cell subsets. When we performed a kinetic analysis of CD31+ recent thymic emigrants and CD45RA+/RO+ T cells, we found evidence for both thymopoiesis and homeostatic proliferation contributing to immune reconstitution. We additionally examined the impact of rATG on peripheral CD4+Foxp3+ T cells. We found that in adults, administration of rATG-induced peripheral expansion and new thymic emigration of T cells with a Treg phenotype, while CD4+Foxp3+ T cells of thymic origin predominated in children, providing the first evidence that rATG induces Treg in vivo. Collectively our data indicate that rATG alters the balance of regulatory to memory effector T cells posttransplant, providing an explanation for how it positively impacts transplant outcome.

Number needed to treat (NNT) to compare benefits of letrozole (LET) with adjuvant chemotherapy (CT) in patients (pts) with node-positive (N+) breast cancer (BC)

581

Background: Adjuvant CT is an accepted treatment for N+ BC. The addition of taxanes to anthracycline based adjuvant CT has been demonstrated to improve overall survival (OS) in all but one study as in table below. BIG 1–98 has reported a survival gain with the aromatase inhibitor LET compared to tamoxifen (TAM). NNT (the reciprocal of absolute benefit) is the number of pts that need to be treated with a new intervention to avoid 1 additional event over the benefit provided by standard therapy. For multiple numerical outcomes from randomized trials, NNT is an effective method to express results in a clinically meaningful way. To evaluate the degree of benefit of LET over TAM in women with early stage N+ BC in BIG 1–98, we compared the NNT for survival benefit from LET to that needed to see benefit from the addition of a taxane to anthracycline based CT based on clinical trial data in BC pts with N+ disease. Methods: 5-yr survival data were taken from the pivotal randomized controlled trial (RCT) for LET (N+ pts from BIG 1–98, TAM arm censored for crossover to LET) and from 4 RCTs of adjuvant CT trials, AC-T, FEC-D, and DAC. NNT was calculated with respect to OS at 5 yrs; outcome is presented as the NNT to save a life (see Table). Results: The NNT to save a life for adjuvant LET vs TAM is comparable to the NNT for the addition of a taxane to anthracycline based CT in women with N+ BC. Conclusions: The magnitude of survival benefit of LET over TAM in terms of NNT is comparable to that needed to see a survival benefit from paradigm- changing modern adjuvant CT regimens. F= fluorouracil, E = epirubicin, C = cyclophosphamide, D = docetaxel, T = paclitaxel, A = doxorubicin

[Table: see text]

[Table: see text]

Age-stratified phase I trial of a combination of bortezomib, gemcitabine, and liposomal doxorubicin in patients with advanced malignancies

14087

Background: Bortezomib, a potent proteasome and NF-kB inhibitor, potentiates the activity of chemotherapy in a variety of tumors in vitro and in mouse models, and preclinical data suggest that the combination of bortezomib, gemcitabine, and liposomal doxorubicin is synergistic. Because tolerance to combination therapy may be attenuated in elderly patients, we performed a phase I age- stratified trial to determine the maximum tolerated dose (MTD), toxicity, and antitumor activity of this combination. Methods: Starting doses were bortezomib 0.7 mg/m2 (days 1 and 8), gemcitabine 500 mg/m2 (days 1 and 8), and liposomal doxorubicin 20 mg/m2 (day 1). Two parallel age-stratified arms (< 65 and = 65 years old) were accrued, with at least three patients per dose level per arm. Each treatment cycle was 21 days. Results: 47 patients have enrolled, and the MTD has not yet been reached. For patients < 65 years old, accrual continues at the ninth dose level with bortezomib 1.3 mg/m2 (days 1, 4, 8, 11), gemcitabine 800 mg/m2 (days 1 and 8), and liposomal doxorubicin 40 mg/m2 (day 1). For patients = 65 years old, accrual continues at the fourth dose level with bortezomib 1.0 mg/m2 (days 1, 4, 8, 11), gemcitabine 800 mg/m2 (days 1 and 8) and liposomal doxorubicin 20 mg/m2 (day 1). The most common side effects have been thrombocytopenia and neutropenia, with thrombocytopenia necessitating dose delays and withholding of doses. In the arm with patients = 65 years old, a dose-limiting toxicity of grade 3 fatigue was observed at dose level 4, and that cohort is currently undergoing dose expansion. Seven patients have achieved a partial response, including one patient with small cell lung carcinoma (6 months; 3 prior therapies) and all of six evaluable patients with cutaneous T cell lymphoma (1, 3, 4, 6, 7, and 8 months; median 4 prior therapies). Stable disease = 6 months was observed in 5 patients with various solid tumors (7, 7, 8, 9, and 9 months; median 4 prior therapies). Conclusions: This combination regimen is well tolerated. Dose-limiting toxicity has developed earlier in the elderly cohort, as predicted. Antitumor activity in heavily pretreated patients with advanced malignancies has been observed.

No significant financial relationships to disclose.

Curcumin and pancreatic cancer: Phase II clinical trial experience

4599

Background: Pancreatic cancer is virtually always lethal, and the only FDA-approved therapies–gemcitabine and erlotinib–produce objective responses in less than 10% of patients. Curcumin (diferuloyl methane) is a plant-derived dietary ingredient that suppresses NF-κB and numerous other pathways relevant to pancreatic cancer and has potent preclinical anti-tumor activity. Herein, we evaluated the safety and potential antitumor activity of curcumin against advanced pancreatic cancer, and its impact on biologic correlates. Methods: Patients received 8 grams of curcumin by mouth daily for two months and were then restaged. Maintenance therapy was continued at the same dose and schedule until disease progression. Results: Twenty-five patients were enrolled as of the date of analysis, with 21 evaluable for response. Circulating curcumin was detectable, albeit at low steady-state levels (about 31 ng/ml), suggesting poor oral bioavailability. To date, two patients have had prolonged stable disease (8 and 12+ months). Interestingly, one patient had a brief, but marked tumor regression (73%) (accompanied by significant increases (4–35-fold) in serum cytokine (interleukin-6 (IL-6), IL-8, IL-10, and IL-1 receptor antagonist (IL-1RA) levels). No toxicities have been observed. Curcumin down-regulated expression of NF-κB, COX-2 and phosphorylated STAT3 in peripheral blood mononuclear cells (PBMC) from patients (most of whom had baseline levels considerably higher than those found in healthy volunteers)although the decrease did not reach statistical significance for p65. Curcumin was determined in patient plasma samples after enzymatic digestion with glucuronidase enzyme. While there was considerable variation in plasma curcumin levels from patient to patient, drug levels peaked at 22–41 ng/ml and remained relatively constant over the entire 4 week experimental period. Conclusions: We conclude that oral curcumin is well tolerated and, despite its limited absorption, has biologic activity in patients with pancreatic cancer.

[Table: see text]

No significant financial relationships to disclose.

Phase II clinical trial of curcumin in patients with advanced pancreatic cancer

14151

Background: Pancreatic cancer is virtually always lethal, and the only FDA-approved therapies- gemcitabine and erlotinib- produce objective responses in less than 10% of patients. Curcumin (diferuloyl methane) is a plant- derived compound that inhibits the nuclear factor-kappa B (NF-kappa B) transcription factor (central to pancreatic cancer growth) and has substantial antitumor activity in preclinical models. We evaluated the toxicity and anti-tumor activity of curcumin, and its impact on survival and biologic correlates. Methods: Patients received 8 grams of curcumin (Sabinsa Corp.) by mouth daily for two months. Maintenance therapy was continued at the same dose and schedule until disease progression. Results: Seventeen patients were enrolled as of the date of analysis. Six were inevaluable: noncompliance (n = 1), never dosed (n = 1), noted to have gastric obstruction after one dose (n = 1), and too early (n = 3). Eleven patients were evaluable for response and 15 were evaluable for toxicity. To date, four patients have stable disease (2+, 2+, 3+ and 7 months) and one patient had a brief partial remission (73% reduction in tumor size by RECIST) that lasted one month. No toxicities have been observed. Serum was available for evaluation of pre-and post-dose cytokine levels in thirteen patients. Interestingly, the patient with the partial remission had marked increases (4–35 fold) in serum IL-1 receptor antagonist, IL-6, IL-10 and IL-8 levels. One to three other patients also had post-treatment increases in one or more of the above cytokines, albeit to a lesser extent (2–6 fold). Conclusions: We conclude that curcumin is well tolerated and our preliminary results suggest biologic activity in pancreatic cancer. Supported in part by the National Cancer Institute grant R21 CA 104337–01, The Topfer Fund for Pancreatic Cancer and Pancreatic SPORE grant 1 P20 CA10193–03.

No significant financial relationships to disclose.

Phase I study of the safety and efficacy of atiprimod, a novel azaspirine, for patients with advanced cancer

13050

Background: Atiprimod (N-N-diethl-8,8-dipropyl-2-azaspiro [4.5] decane-2-propanamine) is an oral cationic azaspirane that suppresses angiogenesis by inhibiting both bFGF and VEGF induced proliferation and migration. Atiprimod has been shown to down-regulate multiple growth factors involved in tumor progressions and metastases, including IL-6, TNF-α, and VEGF. Methods: This is an ongoing, single-center, open-label, ascending dose (modified Fibonacci) Phase I trial of oral atiprimod in patients with advanced cancers (3+3 design). Atiprimod was given orally for 14 days every 28-day cycle. The primary objectives are to identify the MTD and to evaluate the safety of atiprimod; the secondary objectives include measuring PK and describing efficacy. Data from these patients enrolled are presented here. Results: Fourteen patients have been treated to date with 60 mg tablets (N = 3), 60 mg capsules (N = 3), 90 mg capsules (N = 3) and 120 mg capsules (N = 5). The most common side effects, which occurred in over half the patients, were related to the gastrointestinal system, and include nausea (11), diarrhea (7), vomiting (4) abdominal pain (2) and dyspepsia (2). These events were generally low-grade, occurred primarily during days of active drug administration and tended to resolve during off-drug days. Less common adverse events were sinus headaches, and elevated serum transaminases, alkaline phosphatase and creatinine. One patient who received prolonged therapy (7 months) developed fever and multi-organ failure of unclear etiology. One patient with uterine leiomyosarcoma experienced a DLT (syncope and hypotension) at 120 mg/day, and that dose level is therefore being expanded up to 6 patients. One patient with midgut carcinoid tumor and liver metastasis achieved a partial remission lasting 2+ months (50% decrease in maximum diameter by RECIST). Three patients (carcinoid = 2 and thymoma = 1) had stable disease for four, four and six months, respectively. Conclusions: Preliminary data indicate that atiprimod was reasonably tolerated, with predominantly gastrointestinal side effects. There is early evidence of anti-tumor activity in carcinoid tumors. Dose escalation continues.

[Table: see text]

The internal mechanics of the intervertebral disc under cyclic loading

The mechanics of the intervertebral disc (IVD) under cyclic loading are investigated via a one-dimensional poroelastic model and experiment. The poroelastic model, based on that of Biot (J. Appl. Phys. 12 (1941) 155; J. Appl. Mech. 23 (1956) 91), includes a power-law relation between porosity and permeability, and a linear relation between the osmotic potential and solidity. The model was fitted to experimental data of the unconfined IVD undergoing 5 cyclic loads of 20 min compression by an applied stress of 1MPa, followed by 40 min expansion. To obtain a good agreement between experiment and theory, the initial elastic deformation of the IVD, possibly associated with the bulging of the IVD into the vertebral bodies or laterally, was removed from the experimental data. Many combinations of the permeability-porosity relationship with the initial osmotic potential (pi(i)) were investigated, and the best-fit parameters for the aggregate modulus (H(A)) and initial permeability (k(i)) were determined. The values of H(A) and k(i) were compared to literature values, and agreed well especially in the context of the adopted high-stress testing regime, and the strain related permeability in the model.

Effect of frozen storage on the creep behavior of human intervertebral discs

STUDY DESIGN

A biomechanical study of the compressive creep behavior of the human intervertebral disc before and after frozen storage.

OBJECTIVES

To determine whether frozen storage alters the time-dependent response of the intact human intervertebral disc.

SUMMARY OF BACKGROUND DATA

The biomechanical properties of the intervertebral disc are generally determined using specimens that have been previously frozen. Although it is well established that freezing does not alter the elastic response of the disc, recent data demonstrate that freezing permanently alters the time-dependent mechanical behavior of porcine discs.

METHODS

Twenty lumbar motion segments from 10 human spines were harvested between 12 and 36 hours postmortem. The specimens were randomly assigned to one of two groups: Group 1 was tested promptly, stored frozen for 3 weeks, then thawed, and tested a second time; Group 2 was stored frozen for 3 weeks, thawed, and then tested. Each specimen was subjected to 5 cycles of compressive creep under 1 MPa for 20 minutes, followed by a 40-minute recovery under no load. After testing each specimen was graded on a degeneration scale. A fluid transport model was used to parameterize the creep data.

RESULTS

There was no statistically significant effect of freezing on the elastic or creep response of the discs. The degree of pre-existing degeneration had a significant effect on the creep response, with the more degenerated discs appearing more permeable.

CONCLUSIONS

Frozen storage for a reasonable time with a typical method does not significantly alter the creep response of human lumbar discs. Freezing may produce subtle effects, but these potential artifacts do not appear to alter the discs' time-dependent behavior in any consequential way. These results may not apply to tissue kept frozen for long durations and with poor packaging.

A histone variant, Htz1p, and a Sir1p-like protein, Esc2p, mediate silencing at HMR

Silencing at HMR requires silencers, and one of the roles of the silencer is to recruit Sir proteins. This work focuses on the function of Sir1p once it is recruited to the silencer. We have generated mutants of Sir1p that are recruited to the silencer but are unable to silence, and we have utilized these mutants to identify four proteins, Sir3p, Sir4p, Esc2p, and Htz1p, that when overexpressed, restored silencing. The isolation of Sir3p and Sir4p validated this screen. Molecular analysis suggested that Esc2p contributed to silencing in a manner similar to Sir1p and probably helped recruit or stabilize the other Sir proteins, while Htz1p present at HMR assembled a specialized chromatin structure necessary for silencing.

Analysis of eryBI, eryBIII and eryBVII from the erythromycin biosynthetic gene cluster in Saccharopolyspora erythraea

The gene cluster (ery) governing the biosynthesis of the macrolide antibiotic erythromycin A by Saccharopolyspora erythraea contains, in addition to the eryA genes encoding the polyketide synthase, two regions containing genes for later steps in the pathway. The region 5' of eryA that lies between the known genes ermE (encoding the erythromycin resistance methyltransferase) and eryBIII (encoding a putative S-adenosylmethionine-dependent methyltransferase), and that contains the gene eryBI (orf2), has now been sequenced. The inferred product of the eryBI gene shows striking sequence similarity to authentic beta-glucosidases. Specific mutants were created in eryBI, and the resulting strains were found to synthesise erythromycin A, showing that this gene, despite its position in the biosynthetic gene cluster, is not essential for erythromycin biosynthesis. A mutant in eryBIII and a double mutant in eryBI and eryBIII were obtained and the analysis of novel erythromycins produced by these strains confirmed the proposed function of EryBIII as a C-methyltransferase. Also, a chromosomal mutant was constructed for the previously sequenced ORF19 and shown to accumulate erythronolide B, as expected for an eryB mutant and consistent with its proposed role as an epimerase in dTDP-mycarose biosynthesis.

Ste5 RING-H2 domain: role in Ste4-promoted oligomerization for yeast pheromone signaling

Ste5 is a scaffold for the mitogen-activated protein kinase (MAPK) cascade components in a yeast pheromone response pathway. Ste5 also associates with Ste4, the beta subunit of a heterotrimeric guanine nucleotide-binding protein, potentially linking receptor activation to stimulation of the MAPK cascade. A RING-H2 motif at the Ste5 amino terminus is apparently essential for function because Ste5(C177S) and Ste5(C177A C180A) mutants did not rescue the mating defect of a ste5Delta cell. In vitro Ste5(C177A C180A) bound each component of the MAPK cascade, but not Ste4. Unlike wild-type Ste5, the mutant did not appear to oligomerize; however, when fused to a heterologous dimerization domain (glutathione S-transferase), the chimeric protein restored mating in an ste5Delta cell and an ste4Delta ste5Delta double mutant. Thus, the RING-H2 domain mediates Ste4-Ste5 interaction, which is a prerequisite for Ste5-Ste5 self-association and signaling.

Mutational analysis of STE5 in the yeast Saccharomyces cerevisiae: application of a differential interaction trap assay for examining protein-protein interactions

Ste5 is essential for the yeast mating pheromone response pathway and is thought to function as a scaffold that organizes the components of the mitogen-activated protein kinase (MAPK) cascade. A new method was developed to isolate missense mutations in Ste5 that differentially affect the ability of Ste5 to interact with either of two MAPK cascade constituents, the MEKK (Ste11) and the MEK (Ste7). Mutations that affect association with Ste7 or with Ste11 delineate discrete regions of Ste5 that are critical for each interaction. Co-immunoprecipitation analysis, examining the binding in vitro of Ste5 to Ste11, Ste7, Ste4 (G protein beta subunit), and Fus3 (MAPK), confirmed that each mutation specifically affects the interaction of Ste5 with only one protein. When expressed in a ste5 delta cell, mutant Ste5 proteins that are defective in their ability to interact with either Ste11 or Ste7 result in a markedly reduced mating proficiency. One mutation that clearly weakened (but did not eliminate) interaction of Ste5 with Ste7 permitted mating at wild-type efficiency, indicating that an efficacious signal is generated even when Ste5 associates with only a small fraction of (or only transiently with) Ste7. Ste5 mutants defective in association with Ste11 or Ste7 showed strong interallelic complementation when co-expressed, suggesting that the functional form of Ste5 in vivo is an oligomer.

Casein kinase II catalyzes tyrosine phosphorylation of the yeast nucleolar immunophilin Fpr3

In the yeast Saccharomyces cerevisiae, the nucleolar immunophilin, Fpr3, is phosphorylated at tyrosine and dephosphorylated by the phosphotyrosine-specific phosphoprotein phosphatase, Ptp1. In Ptp1-deficient cells, Fpr3 contains phospho-Tyr at a single site (Tyr184), but also contains phospho-Ser and phospho-Thr. Ser186 (adjacent to Tyr184) is situated within a canonical site for phosphorylation by casein kinase II (CKII). Yeast cell lysates contain an activity that binds to Fpr3 in vitro and phosphorylates Fpr3 at Ser, Thr, and Tyr; this activity was found to be dependent on expression of functional yeast CKII. Moreover, purified Fpr3 was phosphorylated on Tyr184 in vitro by either purified yeast CKII or purified, bacterially-expressed human CKII. Likewise, phosphorylation of Fpr3 at tyrosine in vivo was markedly enhanced in yeast cells overexpressing a heterologous (Drosophila) CKII, but was undetectable in yeast cells carrying only a temperature-sensitive allele of the endogenous CKII, even when the cells were grown at a permissive temperature. Phosphorylation of Fpr3 at Tyr184 by CKII in vitro lagged behind phosphorylation of Fpr3 at Ser, and was accelerated by pre-phosphorylation of Fpr3 at Ser using CKII. Furthermore, synthetic peptides corresponding to the sequence surrounding Tyr184 that contained P-Ser (or Glu) at position 186 were much more efficient substrates for CKII phosphorylation of Tyr184 than a synthetic peptide containing Ala at position 186. These findings indicate that CKII phosphorylates Fpr3 at tyrosine and serine both in vivo and in vitro and thus possesses dual specificity. These results also indicate that Tyr184 is phosphorylated by CKII via a two-step process, in which phosphorylation at the +2 position provides a negatively-charged specificity determinant that allows subsequent phosphorylation of Tyr184.

Prenylated isoforms of yeast casein kinase I, including the novel Yck3p, suppress the gcs1 blockage of cell proliferation from stationary phase

The GCS1 gene of the budding yeast Saccharomyces cerevisiae mediate the resumption of cell proliferation from the starved, stationary-phase state. Here we identify yeast genes that, in increased dosages, overcome the growth defect of gcs1 delta mutant cells. Among these are YCK1 (CK12) and YCK2 (CKI1), encoding membrane-associated casein kinase I, and YCK3, encoding a novel casein kinase I isoform. Some Yck3p gene product was found associated with the plasma membrane, like Yck1p and Yck2p, but most confractionated with the nucleus, like another yeast casein kinase I isoform, Hrr25p. Genetic studies showed that YCK3 and HRR25 constitute an essential gene family and that Yck3p can weakly substitute for Yck1p-Yck2p. For gcs1 delta suppression, both a protein kinase domain and a C-terminal prenylation motif were shown to be necessary. An impairment in endocytosis was found for gcs1 delta mutant cells, which was alleviated by an increased YCK2 gene dosage. The ability of an increased casein kinase I gene dosage to suppress the effects caused by the absence of Gcs1p suggests that Gcs1p and Yck1p-Yck2p affect parallel pathways.

Immunophilins in the Yeast Saccharomyces cerevisiae: A Different Spin on Proline Rotamases

The clinically used immunosuppressant compounds-FK506, rapamycin, and cyclophilin A-are all natural products that were originally detected because of their antifungal action, not because of their fortuitous effects on the human immune system. Genetic and biochemical approaches have been used to identify binding proteins that serve as the receptors for these antibiotics in cells of the budding yeast Saccharomyces cerevisiae. Three FK506/rapamycin-binding proteins (FKBPs) and six cyclosporin-A-binding proteins (cyclophilins) have been characterized in some detail, but there is evidence that additional members of both families exist in this organism. Cloning of the corresponding genes has shown that the yeast gene products are strikingly similar to their mammalian counterparts and possess peptidylprolyl-cis, trans-isomerase (proline rotamase) activity in vitro. Genetic analysis in yeast has confirmed, and significantly extended, complementary research in animal cell systems that has shed light on the roles that the FKBPs and the cyclophilins play in the mechanism of action of the immunosuppressant drugs. The application of genetic methods in yeast is also beginning to provide additional insights into the function of these proteins in normal cell physiology.

A member of a novel family of yeast ‘zn-finger’ proteins mediates the transition from stationary phase to cell proliferation

The cloning and molecular characterization of the GCS1 gene from the budding yeast Saccharomyces cerevisiae show that stationary phase is in fact a unique developmental state, with requirements to resume cell proliferation that can be distinct from those for maintenance of proliferation. Deletion of the GCS1 gene products a novel phenotype: stationary-phase mutant cells do not resume proliferation at a restrictive temperature of 15 degrees C, but mutant cells lacking Gcs1p that are proliferating at the permissive temperature of 29 degrees C continue to proliferate after transfer to 15 degrees C as long as nutrients are available. The GCS1 gene sequence predicts a 39 kDa polypeptide with a novel 'Zn-finger' motif. A point mutation within the finger motif produces a phenotype that mimics that of deletion of the GCS1 gene, showing that the finger motif is essential for full Gcs1p activity. Gcs1p and the products of two newly identified genes, SPS18 and GLO3, constitute a family of novel Zn-finger proteins.

Budding and fission yeast casein kinase I isoforms have dual-specificity protein kinase activity

We have examined the activity and substrate specificity of the Saccharomyces cerevisiae Hrr25p and the Schizosaccharomyces pombe Hhp1, Hhp2, and Cki1 protein kinase isoforms. These four gene products are isotypes of casein kinase I (CKI), and the sequence of these protein kinases predicts that they are protein serine/threonine kinases. However, each of these four protein kinases, when expressed in Escherichia coli in an active form, was recognized by anti-phosphotyrosine antibodies. Phosphoamino acid analysis of 32P-labeled proteins showed phosphorylation on serine, threonine, and tyrosine residues. The E. coli produced forms of Hhp1, Hhp2, and Cki1 were autophosphorylated on tyrosine, and both Hhp1 and Hhp2 were capable of phosphorylating the tyrosine-protein kinase synthetic peptide substrate polymer poly-E4Y1. Immune complex protein kinases assays from S. pombe cells showed that Hhp1-containing precipitates were associated with a protein-tyrosine kinase activity, and the Hhp1 present in these immunoprecipitates was phosphorylated on tyrosine residues. Although dephosphorylation of Hhp1 and Hhp2 by Ser/Thr phosphatase had little effect on the specific activity, tyrosine dephosphorylation of Hhp1 and Hhp2 caused a 1.8-to 3.1-fold increase in the Km for poly-E4Y1 and casein. These data demonstrate that four different CKI isoforms from two different yeasts are capable of protein-tyrosine kinase activity and encode dual-specificity protein kinases.

Characterization of two protein kinases from Schizosaccharomyces pombe involved in the regulation of DNA repair

We have identified two novel genes designated hhp1+ and hhp2+ in the fission yeast Schizosaccharomyces pombe. The hhp1+ and hhp2+ genes encode two closely related protein kinases that share significant sequence identities with Hrr25p from Saccharomyces cerevisiae. Characterization of strains harboring single and double mutations in the hhp+ genes reveals DNA repair defects in these cells. Schizosaccharomyces pombe strains lacking either or both Hhp activities reveal differences in their ability to withstand DNA lesions caused by either methyl methanesulfonate (MMS) or gamma-rays which correlate with their ability to repair DNA strand breaks caused by these agents. We suggest that Hhp1 and Hhp2 are involved in the regulation of distinct and overlapping DNA repair pathways in S. pombe.

Cloning and sequence analysis of genes involved in erythromycin biosynthesis in Saccharopolyspora erythraea: sequence similarities between EryG and a family of S-adenosylmethionine-dependent methyltransferases

The gene cluster (ery) responsible for production of the macrolide antibiotic erythromycin by Saccharopolyspora erythraea is also known to contain ermE, the gene conferring resistance to the antibiotic. The nucleotide sequence has been determined of a 4.5 kb portion of the biosynthetic gene cluster, from a region lying between 3.7 kb and 8.2 kb 3' of ermE. This has revealed the presence of four complete open reading frames, including the previously known ery gene eryG, which catalyses the last step in the biosynthetic pathway. Comparison of the amino acid sequence of EryG with the sequence of other S-adenosylmethionine (SAM)-dependent methyltransferases has revealed that one of the sequence motifs previously suggested to be part of the SAM-binding site is present not only in EryG but also in many other recently sequenced SAM-dependent methyltransferases. Previous genetic studies have shown that this region also contains gene(s) involved in hydroxylation of the intermediate 6-deoxyerythronolide B. One of the three other open reading frames (eryF) in fact shows very high sequence similarity to known cytochrome P450 hydroxylases. An adjacent gene (ORF5) shows a strikingly high degree of similarity to prokaryotic and eukaryotic acyltransferases and thioesterases.

Control of the initiation of sporulation in Bacillus subtilis by a phosphorelay

Sporulation in Bacillus subtilis is a developmental process induced as a response to nutritional stress. Activation of sporulation-specific gene transcription is under the control of the spoOA gene product. The SpoOA protein and the SpoOF protein are both homologous to response regulator proteins of two-component regulatory systems which control bacterial responses to a variety of environmental challenges. Response regulators are activated by specific kinases which phosphorylate them. In this study, it was shown that phosphorylation of SpoOA occurs via a phosphotransferase which is the product of the spoOB locus. The phosphodonor in this reaction is the phosphorylated form of SpoOF. It is postulated that SpoOF acts as a secondary messenger that can be phosphorylated by a variety of kinases depending on the particular environmental stress. The series of phosphate transfer reactions in this system is called a phosphorelay. The end product of this series of reactions is SpoOA approximately P which is shown to have greater affinity for the DNA target, the OA box, of SpoOA on the abrB promoter than the unphosphorylated form. SpoOA approximately P, but not SpoOA, was shown to be an activator of transcription of the spoIIA operon which codes for the sporulation-specific sigma factor sigma F. Thus, the initiation of sporulation is dependent on SpoOA approximately P which arises through the phosphorelay and which acts as a transcription factor to repress certain genes, e.g. abrB, and activate others, e.g. spoIIA.

Genetically identified protein kinases in yeast. II: DNA metabolism and meiosis

Genetic analysis of protein kinases in Saccharomyces cerevisiae has revealed protein phosphorylation as a key regulatory mechanism both in the mitotic cell cycle and in meiosis. This article reviews genetically identified protein kinases that are associated with DNA metabolism and the meiotic pathway.

Genetically identified protein kinases in yeast. I: Transcription, translation, transport and mating

Studies from a wide array of different fields using Saccharomyces cerevisiae as an experimental organism have uncovered protein phosphorylation as a recurrent theme in the regulation of diverse cellular activities. Protein kinases in yeast regulate a variety of processes; this article discusses several genetically identified protein kinases and the roles that these kinases play in cell growth and development.

A repeated decapeptide motif in the C-terminal domain of the ribosomal RNA methyltransferase from the erythromycin producer Saccharopolyspora erythraea

Re-analysis of the primary structure of the ribosomal RNA N-methyltransferase that confers self-resistance on the erythromycin-producing bacterium Saccharopolyspora erythraea has confirmed the presence of a C-terminal domain containing extensive repeat sequences. Nine tandem repeats can be discerned, with a decapeptide consensus sequence GGRx(H/R)GDRRT, although no single residue is wholly invariant. This highly polar, potentially flexible domain, which is predicted to adopt either a random coil or a structure with beta turns, has a counterpart in the erythromycin methyltransferase of an erythromycin-producing species of Arthrobacter. It also significantly resembles a portion of the C-terminal region of the eukaryotic protein nucleolin, which is unusually rich in dimethylarginine and glycine, and which is also predicted to behave as a random coil in solution. This resemblance, despite the very different roles of these proteins in ribosome biogenesis, strengthens the idea that in both rRNA methyltransferases and nucleolin these C-terminal sequences might contribute to rRNA binding.

Molecular characterization of a gene from Saccharopolyspora erythraea (Streptomyces erythraeus) which is involved in erythromycin biosynthesis

A 7.3 kbp DNA fragment, encompassing the erythromycin (Em) resistance gene (ermE) and a portion of the gene cluster encoding the biosynthetic genes for erythromycin biosynthesis in Saccharopolyspora erythraea (formerly Streptomyces erythraeus) has been cloned in Streptomyces lividans using the plasmid vector pIJ702, and its nucleotide sequence has been determined using a modified dideoxy chain-termination procedure. In particular, we have examined the region immediately 5' of the resistance determinant, where the tandem promoters for ermE overlap the promoters for a divergently transcribed coding sequence (ORF). Disruption of this ORF using an integrational pIJ702-based plasmid vector gave mutants which were specifically blocked in erythromycin biosynthesis, and which accumulated 3-O-alpha-L-mycarosylerythronolide B: this behaviour is identical to that of previously described eryC1 mutants. The eryC1-gene product, a protein of subunit Mr 39,200, is therefore involved either as a structural or as a regulatory gene in the formation of the deoxyamino-sugar desosamine or in its attachment to the macrolide ring.

A bacterial calcium-binding protein homologous to calmodulin

Many of the effects of calcium ions in eukaryotic cells are mediated by calcium-binding regulatory proteins such as calmodulin, in which each calcium-binding site has a distinctive helix-loop-helix conformation termed the EF hand. Protein S from the spore coat of the Gram-negative bacterium Myxococcus xanthus has been shown to resemble calmodulin in its internally-duplicated structure and ability to bind calcium. However, it has a beta-sheet secondary structure rather than the helix-loop-helix arrangement of the eukaryotic proteins. We have determined the complete amino-acid sequence of a calcium-binding protein from the Gram-positive bacterium "Streptomyces erythraeus" by cloning and sequencing the corresponding gene. It contains four EF-hand motifs bearing remarkable sequence similarity to the calcium-binding sites in calmodulin. This implies that the EF-hand super-family may have evolved from ancient proteins present in prokaryotes.