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Oppegard LJ, Barros LM, Pi H, Kornfield J, Hough CL, Rayner SG, Robinson JC, Leary PJ. Premorbid weight in pulmonary arterial hypertension. Pulm Circ 2023; 13:e12308. [PMID: 38027456 PMCID: PMC10663650 DOI: 10.1002/pul2.12308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 10/13/2023] [Accepted: 10/30/2023] [Indexed: 12/01/2023] Open
Abstract
Relationships between obesity and outcomes in pulmonary arterial hypertension (PAH) are complex. Previous work suggested obesity, occurring alongside PAH, may be associated with better survival. In our work, we suggest obesity prior to PAH development is associated with worse survival. This may add a novel temporal element to the "obesity-paradox."
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Affiliation(s)
- Laura J. Oppegard
- Division of Pulmonary, Allergy, and Critical Care MedicineOregon Health & Sciences UniversityPortlandOregonUSA
| | - Lia M. Barros
- Division of Pulmonary Critical, Care and Sleep MedicineUniversity of WashingtonSeattleWashingtonUSA
| | - Hongyang Pi
- Division of Pulmonary Critical, Care and Sleep MedicineUniversity of WashingtonSeattleWashingtonUSA
| | - James Kornfield
- Division of Pulmonary, Allergy, and Critical Care MedicineOregon Health & Sciences UniversityPortlandOregonUSA
| | - Catherine L. Hough
- Division of Pulmonary, Allergy, and Critical Care MedicineOregon Health & Sciences UniversityPortlandOregonUSA
| | - Samuel G. Rayner
- Division of Pulmonary Critical, Care and Sleep MedicineUniversity of WashingtonSeattleWashingtonUSA
| | - Jeffrey C. Robinson
- Division of Pulmonary, Allergy, and Critical Care MedicineOregon Health & Sciences UniversityPortlandOregonUSA
| | - Peter J. Leary
- Division of Pulmonary Critical, Care and Sleep MedicineUniversity of WashingtonSeattleWashingtonUSA
- Department of EpidemiologyUniversity of WashingtonSeattleWashingtonUSA
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Graham BB, Robinson JC, Tuder RM. Fatty Acid Metabolism, Bone Morphogenetic Protein Receptor Type 2, and the Right Ventricle. Am J Respir Crit Care Med 2017; 194:655-6. [PMID: 27628075 DOI: 10.1164/rccm.201603-0592ed] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Brian B Graham
- 1 Department of Medicine University of Colorado Anschutz Medical Campus Aurora, Colorado
| | - Jeffrey C Robinson
- 1 Department of Medicine University of Colorado Anschutz Medical Campus Aurora, Colorado
| | - Rubin M Tuder
- 1 Department of Medicine University of Colorado Anschutz Medical Campus Aurora, Colorado
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Ard JD, Carson TL, Shikany JM, Li Y, Hardy CM, Robinson JC, Williams AG, Baskin ML. Weight loss and improved metabolic outcomes amongst rural African American women in the Deep South: six-month outcomes from a community-based randomized trial. J Intern Med 2017; 282:102-113. [PMID: 28514081 PMCID: PMC6136898 DOI: 10.1111/joim.12622] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND Obesity is highly prevalent in African American women, especially those in the rural southern USA, resulting in persistent health disparities. OBJECTIVE To test the effectiveness of an evidence-based behavioural weight loss intervention delivered by community health advisors to African American women in the rural south. DESIGN AND METHODS Overweight or obese African American women (30-70 years) from eight counties in Mississippi and Alabama participated in a 24-month randomized controlled trial of an evidence-based behavioural weight loss programme augmented with community strategies to support healthy lifestyles (Weight Loss Plus, N = 154) compared to the weight loss programme alone (Weight Loss Only, N = 255). This study reports on 6-month outcomes on primary (weight change) and secondary (waist circumference, blood pressure, lipids, fasting blood glucose) outcomes, coinciding with the completion of the intensive weight loss phase. RESULTS Weight Loss Only participants lost an average of 2.2 kg (P < 0.001). Weight Loss Plus participants lost an average of 3.2 kg (P < 0.001). The proportion of the total sample that lost at least 5% of their body weight was 27.1% with no difference between treatment groups. Similarly, we observed statistically significant reductions in blood pressure, waist circumference and triglycerides in each treatment group, with no statistical differences between groups. CONCLUSION Trained lay health staff and volunteers from the rural southern USA were able to deliver a translation of a high-intensity behavioural intervention targeted to African American women, resulting in clinically meaningful weight loss and improvement in other metabolic outcomes in a significant proportion of participants.
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Affiliation(s)
- J D Ard
- Department of Epidemiology and Prevention, Wake Forest School of Medicine, Winston Salem, NC, USA
| | - T L Carson
- Division of Preventive Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.,Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, USA
| | - J M Shikany
- Division of Preventive Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.,Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Y Li
- Division of Preventive Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.,Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, USA
| | - C M Hardy
- Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, USA
| | - J C Robinson
- School of Nursing, University of Mississippi Medical Center, Jackson, MS, USA
| | - A G Williams
- Division of Preventive Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - M L Baskin
- Division of Preventive Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.,Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, USA
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Robinson JC, Abbott C, Meadows CA, Roach RC, Honigman B, Bull TM. Long-Term Health Outcomes in High-Altitude Pulmonary Hypertension. High Alt Med Biol 2017; 18:61-66. [PMID: 28061144 DOI: 10.1089/ham.2016.0098] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [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: 11/13/2022] Open
Abstract
Robinson, Jeffrey C., Cheryl Abbott, Christina A. Meadows, Robert C. Roach, Benjamin Honigman, and Todd M. Bull. Long-term health outcomes in high-altitude pulmonary hypertension. High Alt Med Biol. 18:61-66, 2017. BACKGROUND High-altitude pulmonary hypertension (HAPH) is one of several known comorbidities that effect populations living at high altitude, but there have been no studies looking at long-term health consequences of HAPH. We aimed to determine whether HAPH during adolescence predisposes to significant pulmonary hypertension (PH) later in life, as well as identify how altitude exposure and HAPH correlate with functional class and medical comorbidities. METHODS We utilized a previously published cohort of 28 adolescents from Leadville, Colorado, that underwent right heart catheterization at 10,150 ft (3094 m) in 1962, with many demonstrating PH as defined by resting mean pulmonary arterial pressure ≥25 mmHg. We located participants of the original study and had living subjects complete demographic and health surveys to assess for the presence of PH and other medical comorbidities, along with current functional status. RESULTS Seventy-five percent of the individuals who participated in the original study were located. Those with HAPH in the past were more prone to have exertional limitation corresponding to WHO functional class >1. Fifty-five years following the original study, we found no significant differences in prevalence of medical comorbidities, including PH, among those with and without HAPH in their youth. CONCLUSIONS Surveyed individuals did not report significant PH, but those with HAPH in their youth were more likely to report functional limitation. With a significant worldwide population living at moderate and high altitudes, further study of long-term health consequences is warranted.
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Affiliation(s)
- Jeffrey C Robinson
- 1 Colorado Pulmonary Vascular Disease Center, Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado School of Medicine , Aurora, Colorado
| | - Cheryl Abbott
- 1 Colorado Pulmonary Vascular Disease Center, Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado School of Medicine , Aurora, Colorado
| | - Christina A Meadows
- 1 Colorado Pulmonary Vascular Disease Center, Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado School of Medicine , Aurora, Colorado
| | - Robert C Roach
- 2 Altitude Research Center and Department of Emergency Medicine, University of Colorado School of Medicine , Aurora, Colorado
| | - Benjamin Honigman
- 2 Altitude Research Center and Department of Emergency Medicine, University of Colorado School of Medicine , Aurora, Colorado
| | - Todd M Bull
- 1 Colorado Pulmonary Vascular Disease Center, Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado School of Medicine , Aurora, Colorado
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Livingston M, Robinson JC, Brown CE, Narayanan RP, Holland D, Fryer AA, Heald AH. Are cholesterol levels being checked and managed appropriately in UK primary care type 2 diabetes? Int J Clin Pract 2015; 69:1389-91. [PMID: 26503576 DOI: 10.1111/ijcp.12717] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Affiliation(s)
- M Livingston
- Department of Blood Sciences, Walsall Manor Hospital, Walsall, UK.
| | - J C Robinson
- Primis, The University of Nottingham, Nottingham, UK
| | - C E Brown
- Department of Endocrinology, Leighton Hospital, Crewe, UK
| | - R P Narayanan
- Manchester Academic Health Sciences Centre, School of Medicine, University of Manchester, Manchester, UK
| | - D Holland
- National Pathology Benchmarking Service, Department of Medicines Management, Keele University, Staffordshire, UK
| | - A A Fryer
- Department of Clinical Biochemistry, Keele University School of Medicine, University Hospital of North Staffordshire, Stoke-on-Trent, UK
| | - A H Heald
- Department of Endocrinology, Leighton Hospital, Crewe, UK
- Manchester Academic Health Sciences Centre, School of Medicine, University of Manchester, Manchester, UK
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Robinson JC, Graham BB, Rouault TC, Tuder RM. The crossroads of iron with hypoxia and cellular metabolism. Implications in the pathobiology of pulmonary hypertension. Am J Respir Cell Mol Biol 2015; 51:721-9. [PMID: 24988529 DOI: 10.1165/rcmb.2014-0021tr] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The pathologic hallmark of pulmonary arterial hypertension (PAH) is pulmonary vascular remodeling, characterized by endothelial cell proliferation, smooth muscle hypertrophy, and perivascular inflammation, ultimately contributing to increased pulmonary arterial pressures. Several recent studies have observed that iron deficiency in patients with various forms of PAH is associated with worsened clinical outcome. Iron plays a key role in many cellular processes regulating the response to hypoxia, oxidative stress, cellular proliferation, and cell metabolism. Given the potential importance of iron supplementation in patients with the disease and the broad cellular functions of iron, we review its role in processes that pertain to PAH.
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Affiliation(s)
- Jeffrey C Robinson
- 1 Program in Translational Lung Research, Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado; and
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Affiliation(s)
- Rubin M Tuder
- 1 Division of Pulmonary Sciences and Critical Care Medicine University of Colorado School of Medicine Aurora, Colorado
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8
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Williams DL, Fitzmaurice T, Lay L, Forster K, Hefford J, Budge C, Blackmore K, Robinson JC, Field HF. Efficacy of antiviral agents in feline herpetic keratitis: Results of anin vitrostudy. Curr Eye Res 2009; 29:215-8. [PMID: 15512970 DOI: 10.1080/02713680490504849] [Citation(s) in RCA: 15] [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: 10/26/2022]
Abstract
PURPOSE To determine, by a plaque reduction assay, the in vitro efficacy of novel antiviral agents in the treatment of feline herpes virus 1 (FHV-1) keratitis in the domestic cat (Felis felis). MATERIALS AND METHODS A standard plaque reduction assay was performed using a laboratory strain of FHV-1 and embryo-derived feline kidney cells to determine the in vitro efficacy of the antiviral drugs penciclovir (PCV), bromovinyldeoxyuridine (BVdU), and (S)-9-(3-hydroxy-2-phosphonylmethoxypropyl) adenine (HPMPA) and to compare these with the drugs acyclovir (ACV) and trifluorothymidine (TFT). Efficacy was assessed by determining the dose of drug at which 50% plaque reduction was noted (ED(50)). RESULTS HPMPA was found to have greatest antiviral activity (ED(50) 0.07 microg/ml). ACV was least active (ED(50) 24 microg/ml), while TFT was active with an ED(50) of 5.7 microg/ml. PCV and BVdU had intermediate activity (ED(50) 1.6 and 1.7 microg/ml, respectively). CONCLUSIONS This study suggests that the efficacy of HPMPA, BVdU, and penciclovir in cats with herpesviral keratitis should be determined in vivo as their efficacy in vitro was substantially greater than that of acyclovir, already shown to have demonstrable but limited clinical antiviral activity.
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Affiliation(s)
- D L Williams
- Department of Clinical Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge, United Kingdom.
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9
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Gong Q, Zhang L, Moss AJ, Vincent GM, Ackerman MJ, Robinson JC, Jones MA, Tester DJ, Zhou Z. A splice site mutation in hERG leads to cryptic splicing in human long QT syndrome. J Mol Cell Cardiol 2008; 44:502-9. [PMID: 18272172 DOI: 10.1016/j.yjmcc.2008.01.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Revised: 01/09/2008] [Accepted: 01/10/2008] [Indexed: 10/22/2022]
Abstract
Mutations in the human ether-a-go-go-related gene (hERG) cause type 2 long QT syndrome. In this study, we investigated the pathogenic mechanism of the hERG splice site mutation 2398+1G>C and the genotype-phenotype relationship of mutation carriers in three unrelated kindreds with long QT syndrome. The effect of 2398+1G>C on mRNA splicing was studied by analysis of RNA isolated from lymphocytes of index patients and using minigenes expressed in HEK293 cells and neonatal rat ventricular myocytes. RT-PCR analysis revealed that the 2398+1G>C mutation disrupted the normal splicing and activated a cryptic splice donor site in intron 9, leading to the inclusion of 54 nt of the intron 9 sequence in hERG mRNA. The cryptic splicing resulted in an in-frame insertion of 18 amino acids in the middle of the cyclic nucleotide binding domain. In patch clamp experiments the splice mutant did not generate hERG current. Western blot and immunostaining studies showed that the mutant expressed an immature form of hERG protein that failed to reach the plasma membrane. Coexpression of the mutant and wild-type channels led to a dominant negative suppression of wild-type channel function by intracellular retention of heteromeric channels. Our results demonstrate that 2398+1G>C activates a cryptic site and generates a full-length hERG protein with an insertion of 18 amino acids, which leads to a trafficking defect of the mutant channel.
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Affiliation(s)
- Qiuming Gong
- Division of Cardiovascular Medicine, Oregon Health and Science University, Portland, OR , USA
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10
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Mirkarimi PB, Spiller E, Baker SL, Stearns DG, Robinson JC, Olynick DL, Salmassi F, Liddle JA, Liang T, Stivers AR. A silicon-based, sequential coat-and-etch process to fabricate nearly perfect substrate surfaces. J Nanosci Nanotechnol 2006; 6:28-35. [PMID: 16573066] [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: 05/08/2023]
Abstract
For many thin-film applications substrate imperfections such as particles, pits, scratches, and general roughness, can nucleate film defects which can severely detract from the coating's performance. Previously we developed a coat-and-etch process, termed the ion beam thin film planarization process, to planarize substrate particles up to approximately 70 nm in diameter. The process relied on normal incidence etching; however, such a process induces defects nucleated by substrate pits to grow much larger. We have since developed a coat-and-etch process to planarize approximately 70 nm deep by 70 nm wide substrate pits; it relies on etching at an off-normal incidence angle, i.e., an angle of approximately 470 degrees from the substrate normal. However, a disadvantage of this pit smoothing process is that it induces defects nucleated by substrate particles to grow larger. Combining elements from both processes we have been able to develop a silicon-based, coat-and-etch process to successfully planarize approximately 70 nm substrate particles and pits simultaneously to at or below 1 nm in height; this value is important for applications such as extreme ultraviolet lithography (EUVL) masks. The coat-and-etch process has an added ability to significantly reduce high-spatial frequency roughness, rendering a nearly perfect substrate surface.
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Affiliation(s)
- P B Mirkarimi
- Lawrence Livermore National Laboratory, Livermore, CA 945550, USA
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11
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Williams DL, Robinson JC, Lay E, Field H. Efficacy of topical aciclovir for the treatment of feline herpetic keratitis: results of a prospective clinical trial and data from in vitro investigations. Vet Rec 2005; 157:254-7. [PMID: 16127135 DOI: 10.1136/vr.157.9.254] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [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: 11/04/2022]
Abstract
This study aimed to evaluate the efficacy of topical ophthalmic aciclovir applied five times daily as a treatment for feline herpesvirus type 1 (FHV-1) keratitis in a group of cats in a first-opinion practice setting. Cats with ocular signs indicative of FHV-1 or Chlamydophila species infection, predominantly conjunctivitis and keratitis, were tested for FHV-1 antigen using an immunofluorescent technique on air-dried conjunctival swabs. They were first treated with topical chlortetracycline with efficacy against Chlamydophila species and then, in cases positive for FHV-1, with topical aciclovir. The time to recovery was determined and illustrated using a Kaplan-Meier plot. Three cats were infected with Chlamydophila species and showed a median time to recovery of 14 days (95 per cent confidence interval [CI] 10 to 18 days), while 30 cats infected with FHV-1 showed a median time to recovery of 12 days (95 per cent CI 10 to 14 days). The drug dose at which 50 per cent plaque reduction (ED50) occurred in a standard plaque reduction assay was determined in an in vitro study. This showed a mean (SD) ED50 of aciclovir of 25 (3.5) mg/ml compared with 0.4 (0.05) mg/ml for trifluorothymidine, a drug known to be efficacious against FHV-1. The study shows that even though aciclovir is generally considered to lack efficacy against ocular FHV-1 infection, when used frequently it can have a beneficial effect in FHV-1 conjunctivitis and keratitis.
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Affiliation(s)
- D L Williams
- Department of Clinical Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES
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12
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Hansen N, Wodtke AM, Goncher SJ, Robinson JC, Sveum NE, Neumark DM. Photofragment translation spectroscopy of ClN3 at 248 nm: determination of the primary and secondary dissociation pathways. J Chem Phys 2005; 123:104305. [PMID: 16178595 DOI: 10.1063/1.1948381] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Photofragmentation translational spectroscopy was used to identify the primary and secondary reaction pathways in the KrF laser (248 nm) photodissociation of chlorine azide (ClN(3)) under collision-free conditions. Both the molecular channel producing NCl (X (3)Sigma,a (1)Delta) + N(2) and the radical channel producing Cl ((2)P(J)) + N(3) were analyzed in detail. Consistent with previously reported velocity map ion imaging experiments [N. Hansen and A. M. Wodtke, J. Phys. Chem. A 107, 10608 (2003)] a bimodal translational energy distribution is seen when Cl atoms are monitored at mz = 35(Cl(+)). Momentum-matched N(3) counterfragments can be seen at mz = 42(N(3) (+)). The characteristics of the observed radical-channel data reflect the formation of linear azide radical and another high-energy form of N(3) (HEF-N(3)) that exhibits many of the characteristics one would expect from cyclic N(3). HEF-N(3) can be directly detected by electron-impact ionization more than 100 mus after its formation. Products of the unimolecular dissociation of HEF-N(3) are observed in the mz = 14(N(+)) and mz = 28(N(2) (+)) data. Anisotropy parameters were determined for the primary channels to be beta = -0.3 for the NCl forming channel and beta = 1.7 and beta = 0.4 for the linear N(3) and HEF-N(3) forming channels, respectively. There is additional evidence for secondary photodissociation of N(3) and of NCl.
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Affiliation(s)
- N Hansen
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, 93106, USA.
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13
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Gong Q, Keeney DR, Robinson JC, Zhou Z. Defective assembly and trafficking of mutant HERG channels with C-terminal truncations in long QT syndrome. J Mol Cell Cardiol 2005; 37:1225-33. [PMID: 15572053 DOI: 10.1016/j.yjmcc.2004.10.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [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] [Received: 06/25/2004] [Revised: 08/12/2004] [Accepted: 10/01/2004] [Indexed: 10/26/2022]
Abstract
Mutations in the human ether-a-go-go-related gene (HERG) cause long QT syndrome type 2 (LQT2). HERG encodes a voltage-gated potassium channel consisting of four subunits. Tetrameric assembly is required for the formation of functional HERG channels. In the present work, we studied the role of assembly in HERG channel dysfunction of LQT2 mutations Q725X and R1014X, both of which cause truncations of the C-terminus of HERG channels. When expressed in HEK293 cells, Q725X did not generate HERG current, while R1014X generated HERG current with markedly reduced amplitude. Western blot analysis showed that both mutations caused defective trafficking of HERG channel proteins. Using sucrose gradient centrifugation we showed that wild type HERG and R1014X formed a tetrameric structure, whereas Q725X was expressed as a monomer. When coexpressed with wild type HERG, R1014X, but not Q725X, caused dominant negative suppression of wild type HERG current. Coimmunoprecipitation experiments showed that the lack of dominant negative effect by Q725X was due to failure of mutant subunits to coassemble with wild type subunits. These results suggest that the Q725X mutation causes HERG channel dysfunction by disruption of tetrameric assembly of HERG channels. In contrast, the R1014X mutation is capable of forming tetrameric structure, and it causes HERG channel dysfunction by defective trafficking of the mutant protein.
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Affiliation(s)
- Qiuming Gong
- Division of Molecular Medicine, Department of Medicine, NRC3, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
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Abstract
In order to evaluate the antimalarial potential of traditional remedies used in French Guiana, 35 remedies were prepared in their traditional form and screened for blood schizonticidal activity in vitro on Plasmodium falciparum chloroquine re4sistant strain (W2). Some of these extracts were screened in vivo against Plasmodium yoelii rodent malaria. Ferriprotoporphyrin inhibition test was also performed. Four remedies, widely used among the population as preventives, were able to inhibit more than 50% of the parasite growth in vivo at around 100 mg/kg: Irlbachia alata (Gentiananceae), Picrolemma pseudocoffea (Simaroubaceae), Quassia amara (Simaroubaceae), Tinospora crispa (Menispermaceae) and Zanthoxylum rhoifolium (Rutaceae). Five remedies displayed an IC50 in vitro < 10 microg/ml: Picrolemma pseudocoffea, Pseudoxandra cuspidata (Annonaceae) and Quassia amara leaves and stem, together with a multi-ingredient recipe. Two remedies were more active than a Cinchona preparation on the ferriprotoporphyrin inhibition test: Picrolemma pseudocoffea and Quassia amara. We also showed that a traditional preventive remedy, made from Geissospermum argenteum bark macerated in rum, was able to impair the intrahepatic cycle of the parasite. For the first time, traditional remedies from French Guiana have been directly tested on malarial pharmacological assays and some have been shown to be active.
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Affiliation(s)
- S Bertani
- Laboratoire de Parasitologie Comparée et Modèles Expérimentaux, Muséum National d'Histoire Naturelle, Paris, France
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Bajt S, Chapman HN, Nguyen N, Alameda J, Robinson JC, Malinowski M, Gullikson E, Aquila A, Tarrio C, Grantham S. Design and performance of capping layers for extreme-ultraviolet multilayer mirrors. Appl Opt 2003; 42:5750-5758. [PMID: 14528939 DOI: 10.1364/ao.42.005750] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Multilayer lifetime has emerged as one of the major issues for the commercialization of extreme-ultraviolet lithography (EUVL). We describe the performance of an oxidation-resistant capping layer of Ru atop multilayers that results in a reflectivity above 69% at 13.2 nm, which is suitable for EUVL projection optics and has been tested with accelerated electron-beam and extreme-ultraviolet (EUV) light in a water-vapor environment. Based on accelerated exposure results, we calculated multilayer lifetimes for all reflective mirrors in a typical commercial EUVL tool and concluded that Ru-capped multilayers have approximately 40x longer lifetimes than Si-capped multilayers, which translates to 3 months to many years, depending on the mirror dose.
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Affiliation(s)
- Sasa Bajt
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA.
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Abstract
OBJECTIVE The enuresis alarm has been widely advocated as an effective intervention in the treatment of childhood nocturnal enuresis. Although there is a body of evidence concerning which pretreatment variables are related to outcome, there is little evidence relating to influential within-treatment variables. This study sought to examine a series of treatment variables against outcome. MATERIAL AND METHODS A total of 66 children with severe primary nocturnal enuresis but with no day-time wetting were treated with a body-worn enuresis alarm. Pre- and within-treatment variables were collected. Success was considered to be 14 consecutive dry nights during a 16-week period. RESULTS A total of 54.5% of children achieved the success criterion, with 12.1% being classed as partial successes. Of the pretreatment variables, only low functional bladder capacity was significantly associated with failure. Inability to be woken by the alarm emerged as the most important within-treatment predictor of failure. CONCLUSIONS The success of alarm treatment is dependent on the child's ability to be aroused by the alarm. Interestingly, of those who successfully became dry, 72.2% slept throughout the night for >80% of nights that they were dry, suggesting that the mode of action of the enuresis alarm is more complex than was previously thought.
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Affiliation(s)
- R J Butler
- Department of Clinical Psychology, Leeds Community & Mental Health NHS Trust, Leeds, UK.
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Abstract
Many of the 250 physician organizations that provide care to California's sixteen million health maintenance organization enrollees are in a state of crisis, squeezed between constrained revenues, rising practice costs, and consumer sentiment that favors unconstrained choice over integrated delivery. Medical groups and independent practice associations are retrenching to their core geographic areas, reducing capitation for drug benefits and hospital services, and abandoning dreams of displacing health plans. Consolidation is accelerating in some areas, as medical groups join with hospitals to extract higher payment rates from insurers and employers. The conjunction of consumerism and premium inflation creates new opportunities for organizations that truly can manage health care, but the challenges roiling California's medical groups may preclude meaningful efforts to seize the initiative.
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Affiliation(s)
- J C Robinson
- School of Public Health, University of California, Berkeley, USA
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Abstract
Combining the economic literature on principal-agent relationships with examples of marketplace innovations allows analysis of the evolution of methods for paying physicians. Agency theory and the economic principles of performance-based compensation are applied in the context of imperfect information, risk aversion, multiple interrelated tasks, and team production efficiencies. Fee-for-service and capitation are flawed methods of motivating physicians to achieve specific goals. Payment innovations that blend elements of fee-for-service, capitation, and case rates can preserve the advantages and attenuate the disadvantages of each. These innovations include capitation with fee-for-service carve-outs, department budgets with individual fee-for-service or "contact" capitation, and case rates for defined episodes of illness. The context within which payment incentives are embedded, includes such non-price mechanisms as screening and monitoring and such organizational relationships as employment and ownership. The analysis has implications for health services research and public policy with respect to physician payment incentives.
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Affiliation(s)
- J C Robinson
- School of Public Health, University of California, Berkeley, CA 94720-7360, USA.
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Abstract
Managed care embodies an effort by employers, the insurance industry, and some elements of the medical profession to establish priorities and decide who gets what from the health care system. After a turbulent decade of trial and error, that experiment can be characterized as an economic success but a political failure. The strategy of giving with one hand while taking away with the other, of offering comprehensive benefits while restricting access through utilization review, has infuriated everyone involved. The protagonists of managed care now are in full retreat, broadening physician panels, removing restrictions, and reverting to fee-for-service payment. Governmental entities are avoiding politically volatile initiatives to balance limited resources and unlimited expectations. By default, if not by design, the consumer is emerging as the locus of priority setting in health care. The shift to consumerism is driven by a widespread skepticism of governmental, corporate, and professional dominance; unprecedented economic prosperity that reduces social tolerance for interference with individual autonomy; and the Internet technology revolution, which broadens access to information and facilitates the mass customization of insurance and delivery.
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Affiliation(s)
- J C Robinson
- School of Public Health, University of California, Berkeley, CA 94720-7360, USA.
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Robinson JC. Organizational economics and health care markets. Health Serv Res 2001; 36:177-89. [PMID: 11327173 PMCID: PMC1089201] [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] Open
Abstract
As health policy emphasizes the use of private sector mechanisms to pursue public sector goals, health services research needs to develop stronger conceptual frameworks for the interpretation of empirical studies of health care markets and organizations. Organizational relationships should not be interpreted exclusively in terms of competition among providers of similar services but also in terms of relationships among providers of substitute and complementary services and in terms of upstream suppliers and downstream distributors. This article illustrates the potential applicability of transactions cost economics, agency theory, and organizational economics more broadly to horizontal and vertical markets in health care. Examples are derived from organizational integration between physicians and hospitals and organizational conversions from nonprofit to for-profit ownership.
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Affiliation(s)
- J C Robinson
- School of Public Health, University of California, Berkeley 94720-7360, USA
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Robinson JC, Kerjan P, Mirande M. Macromolecular assemblage of aminoacyl-tRNA synthetases: quantitative analysis of protein-protein interactions and mechanism of complex assembly. J Mol Biol 2000; 304:983-94. [PMID: 11124041 DOI: 10.1006/jmbi.2000.4242] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.3] [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: 11/22/2022]
Abstract
The structure of the mammalian multi-synthetase complex was investigated in vitro using qualitative and quantitative approaches. This macromolecular assemblage comprises the bifunctional glutamyl-prolyl-tRNA synthetase, the seven monospecific isoleucyl, leucyl, methionyl, glutaminyl, lysyl, arginyl and aspartyl-tRNA synthetases, and the three auxiliary p43, p38 and p18 proteins. The scaffold p38 protein was expressed in Escherichia coli and purified to homogeneity as a His-tagged protein. The different components of the complex were shown to associate in vitro with p38 immobilized on Ni(2+)-coated plates. Interactions between peripheral enzymes and p38 are referred to as central interactions, as opposed to lateral interactions between peripheral enzymes. Kinetic parameters of the interactions were determined by the means of a biosensor-based approach. The two dimeric proteins LysRS and AspRS were found to tightly bind to p38, with a K(d) value of 0.3 and 4.7 nM, respectively. These interactions involved the catalytic core of the enzymes. By contrast, binding of ArgRS or GlnRS to p38 was much weaker (>5 microM). ArgRS and p43, two peripheral components, were shown to interact with moderate affinity (K(d)=93 nM). Since all the components of the complex are tightly associated within this particle, lateral interactions were believed to contribute to the stabilization of this assemblage. Using an in vitro binding assay, concomitant association of several components of the complex on immobilized p38 could be demonstrated, and revealed the involvement of synergistic effects for association of weakly interacting proteins. Taking into account the possible synergy between central and lateral contributions, a sub-complex containing p38, p43, ArgRS and GlnRS was reconstituted in vitro. These data provide compelling evidence for an ordered and concerted mechanism of complex assembly.
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Affiliation(s)
- J C Robinson
- Laboratoire d'Enzymologie et Biochimie Structurales, UPR 9063 du Centre National de la Recherche Scientifique, 1 Avenue de la Terrasse, Gif-sur-Yvette, 91190, France
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Abstract
Internet-related health care firms have accelerated through the life cycle of capital finance and organizational destiny, including venture capital funding, public stock offerings, and consolidation, in the wake of heightened competition and earnings disappointments. Venture capital flooded into the e-health sector, rising from $3 million in the first quarter of 1998 to $335 million two years later. Twenty-six e-health firms went public in eighteen months, raising $1.53 billion at initial public offering (IPO) and with post-IPO share price appreciation greater than 100 percent for eighteen firms. The technology-sector crash hit the e-health sector especially hard, driving share prices down by more than 80 percent for twenty-one firms. The industry now faces an extended period of consolidation between e-health and conventional firms.
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Affiliation(s)
- J C Robinson
- School of Public Health, University of California, Berkeley, USA.
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Abstract
PURPOSE To determine the accuracy of glaucoma detection by frequency-doubling perimetry. METHODS Stereoview optic nerve photographs, visual field examination, intraocular pressure measurements, medical and ocular history, and a screening and full threshold frequency-doubling perimetry examination were performed in a prospective study of consecutive subjects. Inclusion criteria included age of 45 years or older, absence of ocular disease other than glaucoma, cataract, or mild drusen, and Snellen visual acuity of 20/60 or better. A total of 125 eyes in 102 glaucoma subjects and 95 eyes of 95 normal subjects were included. Each eye was classified as "normal," "glaucoma," or "uncertain" by each of three ophthalmologists on the basis of all available clinical information with the exception of frequency-doubling perimetry results. Those in the glaucoma group were subclassified as having early (n = 51), moderate (n = 42), or severe (n = 32) glaucoma on the basis of automated Humphrey visual field criteria. In the glaucoma group, two eyes from a subject were allowed to be included (23 of 102 subjects) if they differed in level of damage because they were never analyzed within the same statistical analysis. RESULTS Several diagnostic algorithms were evaluated. Algorithms based on the most depressed single point, pair of adjacent points, and cluster of three points performed nearly identically. For the screening test, if any abnormality was identified, specificity was 95%, whereas sensitivity was 39%, 86%, and 100% for early, moderate, and severe glaucoma, respectively. For the full threshold test, with at least one point depressed to the P < 0.5% level, specificity measured 91%, whereas sensitivity was 35%, 88%, and 100% for early, moderate, and severe glaucoma, respectively. The two global indices, mean deviation and pattern standard deviation, were also evaluated and were generally less accurate. CONCLUSION Frequency-doubling perimetry, which is rapid and easily administered, is effective at detecting moderate and severe disease and appears well suited for glaucoma screening.
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Affiliation(s)
- J R Trible
- Eye Institute, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
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Abstract
This paper analyzes the for-profit transformation of health care, with emphasis on Internet start-ups, physician practice management firms, insurance plans, and hospitals at various stages in the industry life cycle. Venture capital, conglomerate diversification, publicly traded equity, convertible bonds, retained earnings, and taxable corporate debt come with forms of financial accountability that are distinct from those inherent in the capital sources available to nonprofit organizations. The pattern of for-profit conversions varies across health sectors, parallel with the relative advantages and disadvantages of for-profit and nonprofit capital sources in those sectors.
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Abstract
CONTEXT Independent practice associations (IPAs) are developing new methods of physician reimbursement to balance the objectives of encouraging individual productivity and clinical cooperation. The economic literature on payment incentives, derived from nonhealth industries, predicts that methods blending elements of fee-for-service and capitation will outperform exclusive reliance on either form of payment. OBJECTIVE To identify emerging payment methods within IPA physician groups that contract with managed care organizations. DESIGN AND SETTING Case studies of 7 large IPAs in the San Francisco, Calif, metropolitan region that served 826000 health maintenance organization (HMO) patients during the summer and fall of 1998. MAIN OUTCOME MEASURE Payment methods of IPAs for primary care physicians, specialists, and physicians grouped by specialty department within the overall IPA structure. RESULTS All the IPAs contracted with multiple HMOs for the full range of primary and specialty care physicians' services but paid member physicians using methods that blended elements of fee-for-service and subcapitation. For primary care, most IPAs used monthly capitation adjusted for patient age, sex, and selected diagnoses, supplemented with fee-for-service payment for a wide range of visits and procedures, including patient visits in subacute, skilled nursing facility, emergency department, or home settings; for preventive care services; for office procedures requiring expensive supplies; and, most importantly, for borderline primary care procedures that either could be performed directly or referred to specialty care. All the IPAs paid specialty departments on a capitated basis and delegated to the departments responsibility for allocating the budget among individuals. Allocation mechanisms for individual specialists included adjusted fee-for-service, referral-based capitation, and blends of both. CONCLUSION Our results and case studies indicate that IPAs are developing payment methods that blend elements of fee-for-service and capitation in innovative ways for primary care and specialty physicians.
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Affiliation(s)
- J C Robinson
- University of California School of Public Health, Berkeley 94720-7360, USA.
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Bharucha CF, Robinson JC, Moore FL, Sundaram B, Niu Q, Raizen MG. Dynamical localization of ultracold sodium atoms. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 1999; 60:3881-95. [PMID: 11970223 DOI: 10.1103/physreve.60.3881] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/1998] [Revised: 05/21/1999] [Indexed: 04/18/2023]
Abstract
We report a study of atomic motion in time-dependent optical potentials. We measure momentum transfer in parameter regimes for which the classical dynamics are chaotic, and observe the quantum suppression of chaos by dynamical localization. The high degree of control over the experimental parameters enables detailed comparisons with theoretical predictions, and opens new avenues for investigating quantum chaos.
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Affiliation(s)
- C F Bharucha
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712-1081, USA
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Abstract
OBJECTIVE To determine the diagnostic accuracy of scanning laser polarimetry. SUBJECTS AND METHODS A total of 95 healthy subjects and 102 patients with glaucoma met all inclusion criteria. Data collected on each participant included an automated visual field examination, stereoview optic nerve head photographs, intraocular pressure measurement, and a screening and full scanning laser polarimetry study. Each participant was classified as "normal," "glaucoma," or "uncertain" by each of 3 ophthalmologists based on all available clinical information, with the exception of the scanning laser polarimetry results. Before data analysis, 4 diagnostic algorithms for the full-test mode and 2 for the screening mode were chosen to be evaluated for their sensitivity and specificity in detecting glaucoma. RESULTS Of the 4 algorithms tested for the full-test mode, "the number" (abnormal test score, >35) had sensitivities of 57%, 71%, and 81% for early, moderate, and severe glaucoma, respectively. Specificity was 89%. For the screening test, sensitivities were much lower, particularly for those with severe glaucoma damage. CONCLUSIONS AND CLINICAL RELEVANCE Scanning laser polarimetry can help to differentiate subjects with normal findings from patients with glaucomatous damage. Even the best algorithm tested, however, failed to detect a substantial number of subjects with severe damage. Further study is needed before scanning laser polarimetry can be recommended as a screening method for glaucoma.
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Affiliation(s)
- J R Trible
- Eye Institute, Medical College of Wisconsin, Milwaukee, USA
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Hubbard WC, Robinson JC, Schmidt K, Rohen JW, Tamm ER, Kaufman PL. Superior cervical ganglionectomy in monkeys: effects on refraction and intraocular pressure. Exp Eye Res 1999; 68:637-9. [PMID: 10328978 DOI: 10.1006/exer.1999.0667] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Abstract
This paper analyzes the transformation of the central organization in the managed care system: the multiproduct, multimarket health plan. It examines vertical disintegration, the shift from ownership to contractual linkages between plans and provider organizations, and horizontal integration--the consolidation of erstwhile indemnity carriers, Blue Cross plans, health maintenance organizations (HMOs), and specialty networks. Health care consumers differ widely in their preferences and willingness to pay for particular products and network characteristics, while providers differ widely in their willingness to adopt particular organization and financing structures. This heterogeneity creates an enduring role for health plans that are diversified into multiple networks, benefit products, distribution channels, and geographic regions. Diversification now is driving health plans toward being national, full-service corporations and away from being local, single-product organizations linked to particular providers and selling to particular consumer niches.
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Quevillon S, Robinson JC, Berthonneau E, Siatecka M, Mirande M. Macromolecular assemblage of aminoacyl-tRNA synthetases: identification of protein-protein interactions and characterization of a core protein. J Mol Biol 1999; 285:183-95. [PMID: 9878398 DOI: 10.1006/jmbi.1998.2316] [Citation(s) in RCA: 144] [Impact Index Per Article: 5.8] [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: 11/22/2022]
Abstract
In eukaryotes, from fly to human, nine aminoacyl-tRNA synthetases contribute a multienzyme complex of defined and conserved structural organization. This ubiquitous multiprotein assemblage comprises a unique bifunctional aminoacyl-tRNA synthetase, glutamyl-prolyl-tRNA synthetase, as well as the monospecific isoleucyl, leucyl, glutaminyl, methionyl, lysyl, arginyl, and aspartyl-tRNA synthetases. Three auxiliary proteins of apparent molecular masses of 18, 38 and 43 kDa are invariably associated with the nine tRNA synthetase components of the complex. As part of an inquiry into the molecular and functional organization of this macromolecular assembly, we isolated the cDNA encoding the p38 non-synthetase component and determined its function. The 320 amino acid residue encoded protein has been shown to have no homolog in yeast, bacteria and archaea, according to the examination of the complete genomic sequences available. The p38 protein is a moderately hydrophobic protein, displays a putative leucine-zipper motif, and shares a sequence pattern with protein domains that are involved in protein-protein interactions. We used the yeast two-hybrid system to register protein connections between components of the complex. We performed an exhaustive search of interactive proteins, involving 10 of the 11 components of the complex. Twenty-one protein pairs have been unambiguously identified, leading to a global view of the topological arrangement of the subunits of the multisynthetase complex. In particular, p38 was found to associate with itself to form a dimer, but also with p43, with the class I tRNA synthetases ArgRS and GlnRS, with the class II synthetases AspRS and LysRS, and with the bifunctional GluProRS. We generated a series of deletion mutants to localize the regions of p38 mediating the identified interactions. Mapping the interactive domains in p38 showed the specific association of p38 with its different protein partners. These findings suggest that p38, for which no homologous protein has been identified to date in organisms devoid of multisynthetase complexes, plays a pivotal role for the assembly of the subunits of the eukaryotic tRNA synthetase complex.
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Affiliation(s)
- S Quevillon
- Laboratoire d'Enzymologie et Biochimie Structurales, UPR 9063 du Centre National de la Recherche Scientifique, Gif-sur-Yvette, 91190, France
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Abstract
Medical groups need financial resources yet most retain no earnings and have no reserves. Physician practice management (PPM) companies have recognized the need for investment and the scarcity of indigenous capital in the physician sector and are rushing to fill the void. Resources are being contributed by venture capitalists, bond underwriters, private investors, pharmaceutical manufacturers, health plans, hospital systems, and public equity markets. The potential contribution of PPM firms is to nurture the intellectual capital of leading physician organizations and diffuse it throughout the health care system. The risk is that short-term financial imperatives will impede necessary long-term investments.
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Abstract
This paper outlines a conceptual framework of organizational diversification and assesses the state of empirical research on hospital organizational change. The literature on economic organization of hospitals, one of the most developed branches of health services research, still has only weak ties to economic theory. Evolving physician-hospital organizations do not fit into existing frameworks based on horizontal integration, vertical integration, or diversification. Empirical research has primarily focused on horizontal integration, and cause-effect relationships are often obscured by models that depart from economic theory and lack controls for self-selection bias. Recent empirical studies indicate that hospital mergers had moderate, rather than dramatic, effects on the rate of change in operating costs, staffing, and scale. Mergers rarely resulted in hospital closure, but were as likely to result in acute care consolidation and restructuring as in conversion to non-acute inpatient uses. While administrative costs were higher in for-profit than non-profit system hospitals, total costs were similar. System hospitals had lower marginal and average costs per stay than independent hospitals. Hospital vertical integration into subacute care was largely an artifact of the governmental uniform pricing system, which encouraged vertical integration. Hospitals that shared governance or financial risks with physicians outperformed those with high levels of physician governance and financial integration (e.g. stock ownership). Formal physician-hospital organizational arrangements often served to coordinate managed care contracting or to forge links with primary care group practices. Hospital diversification into related services improved short-term financial performance over unrelated diversification, although long-term performance was similar.
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Affiliation(s)
- T S Snail
- School of Public Health, University of California, Berkeley 94720, USA.
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Abstract
Historically, the combination of women's rights to care, population concerns and the development of female-oriented contraceptive methods resulted in family planning programs focusing on women's contraceptive needs and little else. The 1994 United Nations Population Conference in Cairo called for an expansion of programs to cover reproductive health in its broadest interpretation. As this concept has developed and been put into practice it has become evident that a key element in reproductive health services should be the inclusion of the sexually active couple.
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Affiliation(s)
- S Becker
- Department of Population Dynamics, Johns Hopkins School of Public Health, Baltimore, MD 21205, USA
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35
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Abstract
CONTEXT Medical groups are growing and merging to improve efficiency and bargaining leverage in the competitive managed care environment. An increasing number are affiliating with physician practice management (PPM) firms that offer capital financing, expertise in utilization management, and global capitation contracts with health insurance entities. These physician organizations provide an alternative to affiliation with a hospital system and to individual physician contracting with health plans. OBJECTIVE To describe the growth, structure, and strategy of PPM organizations that coordinate medical groups in multiple markets and contract with health maintenance organizations (HMOs). DESIGN Case studies, including interviews with administrative and clinical leaders, review of company documents, and analysis of documents from investment bankers, the Securities and Exchange Commission, and industry observers. SETTING Medical groups and independent practice associations (IPAs) in California and New Jersey affiliated with MedPartners, FPA Medical Management, and UniMed. OUTCOME MEASURES Growth in number of primary care and specialty care physicians employed by and contracting with affiliated medical groups; growth in patient enrollment from commercial, Medicare, and Medicaid HMOs; growth in capitation and noncapitation revenues; structure and governance of affiliated management service organizations and professional corporations; and contracting strategies with HMOs. RESULTS Between 1994 and 1996, medical groups and IPAs affiliated with 3 PPMs grew from 3787 to 25763 physicians; 65% of employed physicians provide primary care, while the majority of contracting physicians provide specialty care. Patient enrollment in HMOs grew from 285503 to 3028881. Annual capitation revenues grew from $190 million to $2.1 billion. Medical groups affiliated with PPMs are capitated for most professional, hospital, and ancillary clinical services and are increasingly delegated responsibility by HMOs for utilization management and quality assurance. COMMENT Physician practice management organizations and their affiliated medical groups face the challenge of continuing rapid growth, sustaining stock values, and improving practice efficiencies while maintaining the loyalty of physicians and patients.
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Affiliation(s)
- J C Robinson
- School of Public Health, University of California, Berkeley 94720, USA.
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Quevillon S, Agou F, Robinson JC, Mirande M. The p43 component of the mammalian multi-synthetase complex is likely to be the precursor of the endothelial monocyte-activating polypeptide II cytokine. J Biol Chem 1997; 272:32573-9. [PMID: 9405472 DOI: 10.1074/jbc.272.51.32573] [Citation(s) in RCA: 146] [Impact Index Per Article: 5.4] [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: 02/05/2023] Open
Abstract
p43 is one of the three auxiliary components invariably associated with nine aminoacyl-tRNA synthetases as a multienzyme complex ubiquitous to all eukaryotic cells from flies to humans. The cDNA encoding the hamster protein was isolated by using mixed oligonucleotides deduced from peptide sequences. The 359-amino acid protein is the hamster homologue of the recently reported murine and human EMAP II cytokine implicated in a variety of inflammatory disorders. The sequence of several proEMAP II proteins suggests that the p43 component of the complex is the precursor of the active mature cytokine after cleavage at a conserved Asp residue. The COOH-terminal moiety of p43 is also homologous to polypeptide domains found in bacterial methionyl- or phenylalanyl-tRNA synthetases and in the yeast Arc1p/G4p1 protein that associates with yeast methionyl-tRNA synthetase. Our results implicate the COOH-terminal moiety of p43 as a RNA binding domain. In the native state, as a component of the multisynthetase complex, p43 may be required for tRNA channeling and, after proteolytic processing occurring in tumor cells, would acquire inflammatory properties possibly related to apoptosis. The release of a truncated p43 from the complex could be involved in mediation of the signaling of tumor cells and stimulation of an acute inflammatory response.
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Affiliation(s)
- S Quevillon
- Laboratoire d'Enzymologie et Biochimie Structurales, CNRS-UPR 9063, 91190 Gif-sur-Yvette, France
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Burns LR, Robinson JC. Physician practice management companies: implications for hospital-based integrated delivery systems. Front Health Serv Manage 1997; 14:3-35. [PMID: 10174436] [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: 02/11/2023]
Abstract
Physician practice management companies (PPMCs) are one of the most visible entrants into the industry of managing physician practices, and anywhere from 100-150 are already in operation. Although PPMCs and hospital-based integrated delivery systems (IDSs) differ from each other in many ways, they share a number of common features, including the pursuit of capitation contracts from payors. As a result, PPMCs pose a growing, direct threat to hospital systems in competing for managed care contracts that cover physician service. PPMCs also provide an alternative to hospital-based IDSs at the local market level for physician group consolidation. This article looks at the structure, operation, and strategy of PPMCs and examines what implications their growth will have for hospital-based IDSs.
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Affiliation(s)
- L R Burns
- Wharton School, Philadelphia, PA, USA
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38
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Poole JE, White RD, Kanz KG, Hengstenberg F, Jarrard GT, Robinson JC, Santana V, McKenas DK, Rich N, Rosas S, Merritt S, Magnotto L, Gallagher JV, Gliner BE, Jorgenson DB, Morgan CB, Dillon SM, Kronmal RA, Bardy GH. Low-energy impedance-compensating biphasic waveforms terminate ventricular fibrillation at high rates in victims of out-of-hospital cardiac arrest. LIFE Investigators. J Cardiovasc Electrophysiol 1997; 8:1373-85. [PMID: 9436775 DOI: 10.1111/j.1540-8167.1997.tb01034.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.6] [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: 02/05/2023]
Abstract
INTRODUCTION New automatic external defibrillators (AEDs), which are smaller, lighter, easier to use, and less costly make the goal of widespread AED deployment and early defibrillation for out-of-hospital cardiac arrest feasible. The objective of this study was to observe the performance of a low-energy impedance-compensating biphasic waveform in the out-of-hospital setting on 100 consecutive victims of sudden cardiac arrest. METHODS AND RESULTS AEDs incorporating a 150-J impedance-compensating biphasic waveform were used by 12 EMS systems. Data were obtained from the AED PC card reporting system. Defibrillation was defined as conversion to an organized rhythm or to asystole. Endpoints included: defibrillation efficacy for ventricular fibrillation (VF); restoration of an organized rhythm at the time of patient transfer to an advanced life support (ALS) team or to the emergency department (ED); and time from AED power-on to first defibrillation. The AED correctly identified 44 of 100 patients presenting in VF as requiring a shock (100% sensitivity) and 56 of 100 patients not in VF as not requiring a shock (100% specificity). The time from 911 call to first shock delivery averaged 8.1 +/- 3.0 minutes. A single 150-J biphasic shock defibrillated the initial VF episode in 39 of 44 (89%) patients. The average time from power-on to first defibrillation was 25 +/- 17 seconds. At patient transfer to ALS or ED care, an organized rhythm was present in 34 of 44 (77%) patients presenting with VF. Asystole was present in 7 (16%) and VF in 3 (7%). CONCLUSIONS Low-energy impedance-compensating biphasic waveforms terminate long-duration VF at high rates in out-of-hospital cardiac arrest. Use of this waveform allows AED device characteristics consistent with widespread AED deployment and early defibrillation.
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Affiliation(s)
- J E Poole
- The University of Washington, Seattle 98195, USA.
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Robinson JC, Lozada-Nur F, Frieden I. Oral pemphigus vulgaris: a review of the literature and a report on the management of 12 cases. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997; 84:349-55. [PMID: 9347496 DOI: 10.1016/s1079-2104(97)90030-5] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Twelve cases of oral pemphigus vulgaris are described to illustrate the long-term behavior of the disease and the treatment challenges it presents to the oral medicine practitioner. In addition, we review the literature on oral pemphigus vulgaris with respect to clinical history, signs and symptoms, management, and treatment outcome. Pemphigus vulgaris is a chronic vesiculobullous disease with a potentially fatal outcome. Mortality from pemphigus vulgaris before the development of effective therapies was as high as 90%. Today, with treatment, it is closer to 10%. Involvement of the oral mucosa is common and in most cases precede skin lesions; in our patients, the oral lesions preceded the development of extraoral disease in 75% of cases. Pemphigus vulgaris was more frequent among women (9:3), and there was a tendency for the severity and frequency of disease to decrease with time.
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Affiliation(s)
- J C Robinson
- Department of Stomatology, University of California, San Francisco, USA
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Prielipp RC, Robinson JC, Wilson JA, MacGregor DA, Scuderi PE. Dose response, recovery, and cost of doxacurium as a continuous infusion in neurosurgical intensive care unit patients. Crit Care Med 1997; 25:1236-41. [PMID: 9233753 DOI: 10.1097/00003246-199707000-00028] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [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: 02/04/2023]
Abstract
OBJECTIVES To determine the optimal dosing of doxacurium as a continuous infusion in neurosurgical patients with traumatic brain injury; to determine the effects of bolus administration of doxacurium on heart rate (HR), blood pressure (BP), and intracranial pressure (ICP); to monitor neuromuscular recovery after discontinuation of prolonged doxacurium infusion; and to compare the cost of doxacurium with other current neuromuscular blocking drugs. DESIGN Prospective, open-label study. SETTING Neurosurgical intensive care unit (ICU) of a university-affiliated teaching hospital. PATIENTS Eight critically ill, mechanically ventilated patients with traumatic head injury and normal renal and hepatic function. Patients had ICP monitoring. INTERVENTIONS A bolus injection of doxacurium (0.05 mg/kg) followed by a continuous infusion (0.015 mg/kg/hr), adjusted to maintain one twitch during Train-of-Four nerve stimulation of the adductor pollicis muscle. MEASUREMENTS AND MAIN RESULTS Bolus injections of doxacurium did not alter the HR, BP, or ICP. Patients were paralyzed 66 +/- 12 (SEM) hrs, with recovery of the fourth twitch occurring 118 +/- 19 mins after infusion of the doxacurium was discontined. There were no incidences of prolonged weakness, myopathy, or other adverse events. CONCLUSIONS Continuous infusion of doxacurium provides stable neuromuscular blockade for neurosurgical patients with traumatic brain injury. Doxacurium is devoid of clinically important interactions with HR, BP, or ICP and is less costly than other neuromuscular blockers used in the ICU.
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Affiliation(s)
- R C Prielipp
- Department of Anesthesiology, The Bowman Gray School of Medicine of Wake Forest University, Winston-Salem, NC, USA
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Tamm ER, Rohen JW, Schmidt K, Robinson JC, Wallow IH, Kaufman PL. Superior cervical ganglionectomy in monkeys: light and electron microscopy of the anterior eye segment. Exp Eye Res 1997; 65:31-43. [PMID: 9237862 DOI: 10.1006/exer.1997.0301] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Morphological changes in the anterior eye segment of eight cynomolgus monkeys were investigated 2 days to 2.2 years after unilateral surgical superior cervical ganglionectomy (SCGx). SCGx was confirmed by histologic examination of the excised surgical specimen and persistent ipsilateral miosis. In four short-term monkeys (2, 4, 7 and 11 days), iris, ciliary muscle and trabecular meshwork were studied by electron microscopy. In the other four longer-term monkeys (3 week, 4 week, 5 week, 2.2 year) the anterior eye segment was investigated with tyrosine hydroxylase immunohistochemistry (TH-IR) and catecholamine fluorescence (CF). Electron microscopy of experimental eyes showed characteristic signs of Wallerian degeneration in numerous nerve fibers and terminals in the iris, but to a lesser extent in the ciliary muscle and the trabecular meshwork. TH-IR and CF showed marked interindividual differences. In all experimental eyes, there was a marked reduction, but never a complete absence of adrenergic nerves in the iris. In two animals (4 week and 2.2 years), the adrenergic innervation of the ciliary body and the chamber angle was similarly reduced. In contrast, in the experimental eyes of the other two animals (3 and 5 weeks), changes in adrenergic innervation to the ciliary body and chamber angle were minimal or absent. The results indicate that following apparently complete SCGx in the cynomolgus monkey, reduction of adrenergic innervation to the iris as evidenced by pupillary physiology, electron microscopy, TH-IR and CF does not guarantee reduction in adrenergic innervation to the ciliary body and trabecular meshwork. SCGx may not extirpate all third order sympathetic neurons in the distal stump, or there may be a significant contribution of accessory ganglion cells to the adrenergic innervation of the anterior eye segment.
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Affiliation(s)
- E R Tamm
- Department of Anatomy II, University of Erlangen-Nürnberg, Germany
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Paul R, Ewing CM, Robinson JC, Marshall FF, Johnson KR, Wheelock MJ, Isaacs WB. Cadherin-6, a cell adhesion molecule specifically expressed in the proximal renal tubule and renal cell carcinoma. Cancer Res 1997; 57:2741-8. [PMID: 9205085] [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: 02/04/2023]
Abstract
Cadherins are a family of calcium-dependent, cell-cell adhesion molecules that play an important morphoregulatory role in a wide variety of tissues. Alterations in cadherin function have been implicated in tumor progression in a number of adenocarcinomas. Despite the increasing number of new cadherins identified, little is known about cadherins in normal renal tissue and renal carcinomas. A novel cadherin transcript, cadherin-6, was recently described to be present in renal cancer cell lines and fetal kidney, but no data on protein expression nor tissue localization has been reported. In this study, we demonstrate that the expression of cadherin-6 is restricted to the proximal tubule epithelium. This finding is critical because these cells give rise to the majority of neoplasms of this organ. Furthermore we demonstrate typical cadherin features of cadherin-6, including cytoplasmic binding to alpha- and beta-catenin. We present data of cadherin-6 expression in a series of 32 primary renal cell cancers. Cadherin-6 expression tended to vary with histology in these samples. Whereas the majority of renal cell cancers with histology-associated poor prognosis (i.e., high grade clear cell carcinomas and sarcomatoid renal tumors) show aberrant expression of cadherin-6, in tumors with a favorable prognosis (i.e., low grade clear cell carcinomas and papillary cancers), normal cadherin-6 expression was predominant. Overall, these findings demonstrate specific expression of cadherin-6 in the proximal renal tubules in normal human kidney and suggest that alterations of cadherin-6 expression are associated with progression of renal cell carcinoma.
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Affiliation(s)
- R Paul
- James Buchanan Brady Urological Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
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Abstract
This paper examines the use and abuse of the medical loss ratio in the contemporary health care system and health policy debate. It begins with a survey of the ways in which the medical loss ratio has been interpreted to be something it is not, such as a measure of quality or efficiency. It then analyzes key organizational features of the emerging health care system that complicate measures of financial performance, including integration between payers and providers, diversification of payers across multiple products and distribution channels, and geographic expansion across metropolitan and state lines. These issues are illustrated using medical loss ratios from a range of nonprofit and for-profit health plans. The paper then sketches a strategy for improving the public's understanding of health plan performance as an alternative to continued reliance on the flawed medical loss ratio. This strategy incorporates data on structure and process, service quality, and financial performance.
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Affiliation(s)
- J C Robinson
- School of Public Health, University of California, Berkeley, USA
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Abstract
Physicians and hospitals are pioneering new and more coordinated organizational forms under pressure from market competition. Arms-length "doctor's workshop" relationships are yielding to integrated delivery systems and contractual delivery networks. This article analyzes organizational change in health care through the conceptual lens of institutional economics, defined broadly as including agency theory, transactions cost economics, and the dynamic capabilities view of the firm. These theoretical frameworks highlight three distinct functions of organization under managed care: coordination, governance, and innovation.
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Robinson JC. Decline in hospital utilization and cost inflation under managed care in California. JAMA 1996; 276:1060-4. [PMID: 8847768] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To measure the impact of health maintenance organizations (HMOs) on hospital capacity, utilization, and expenditures between 1983 and 1993. DESIGN Multivariate regression analysis. SETTING Private nonprofit and for-profit hospitals in California with 25 or more beds. PATIENTS Patient discharge abstract data were used to measure growth of HMO penetration of local hospital markets. INTERVENTIONS None. MAIN OUTCOME MEASURES Hospital closures, changes in bed capacity, changes in acute care admissions and length of stay, psychiatric inpatient days, subacute inpatient days, inpatient and outpatient surgical procedures, ambulatory patient visits, and hospital expenditures. RESULTS Between 1983 and 1993 hospital expenditures grew 44% less rapidly in markets with high HMO penetration than in markets with low HMO penetration. Of this, 28% was due to reductions in the volume and mix of services, 6% was due to reductions in bed capacity, and 10% was due to changes in the intensity of services provided. Health maintenance organizations accelerated the substitution of outpatient for inpatient surgery, the shift from acute to subacute inpatient days, and the reduction of psychiatric hospitalization. CONCLUSION Managed care is shifting the acute hospital from the center toward the periphery of the health care system.
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Affiliation(s)
- J C Robinson
- School of Public Health, University of California, Berkeley 94720, USA
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Abstract
OBJECTIVE We report a group of eight patients with a distinctive histological variant of meningioma that is associated with severe peritumoral edema. The clinical presentation, radiographic findings, and histology of this type of tumor may lead to misdiagnosis as an aggressive or malignant process. METHODS We reviewed the histology from patients who had removal of meningiomas performed in our institution between 1978 and 1992. Tumors having abnormal proliferation of cells in the intramural vascular spaces were selected for study; case histories and radiographs were reviewed. Tumor material was subjected to special stains, immunocytochemical examination, and election microscopy. RESULTS Several lesions were misread radiographically as being malignant. Patients underwent craniotomy with complete excision of the tumor. All lesions were small (< or = 3 cm), and no brain invasion, unusual tumor vascularity, or dural sinus involvement was noted in any case. Histologically, the meningioma pattern in each case was meningothelial and benign in appearance. The immunocytochemical and electron microscopic features of the unusual cells in the blood vessel walls are most consistent with their being of pericytic origin. All patients have remained asymptomatic and without evidence of tumor recurrence with follow-up from 3 to 12 years. CONCLUSION These tumors showed proliferation of pericytes in blood vessel walls and represent a new subtype of meningothelial meningioma. The apparently benign nature of these lesions necessitates their recognition. Characteristic findings of pericytic proliferation associated with edema generation have led us to descriptively term this the PEG variant of meningioma.
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Affiliation(s)
- J C Robinson
- Department of Neurosurgery, Wake Forest University, Bowman Gray School of Medicine, Winston-Salem, North Carolina, USA
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Brooks JD, Bova GS, Ewing CM, Piantadosi S, Carter BS, Robinson JC, Epstein JI, Isaacs WB. An uncertain role for p53 gene alterations in human prostate cancers. Cancer Res 1996; 56:3814-22. [PMID: 8706029] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Inactivation of the p53 gene has been implicated in prostate cancer progression. To determine the role of p53 inactivation in the progression of clinical prostatic carcinomas, we assessed 67 tumors derived from patients with clinically localized disease for chromosome 17p and p53 gene allelic loss, p53 gene mutations using single-strand conformational polymorphism and direct sequencing, and p53 protein expression using immunohistochemical staining. Of 55 informative tumors, 10 demonstrated loss of 17p or the p53 gene; however, only a single tumor had a mutation in its remaining p53 allele. Significant p53 overexpression was observed in 2 of 38 tumors, and 9 others had faint staining of a few nuclei ( < 1%). p53 overexpression occurred in no informative tumor with allelic loss or mutation. In a 1-7-year follow-up, positive immunohistochemical staining did not confer an increased risk of recurrence (risk of recurrence, 0.86, P = 0.78), whereas allelic loss of chromosome 17p appeared to be highly correlated with recurrence (risk of recurrence, 3.7, P = 0.003). In an unrelated group of 42 patients with metastatic prostate cancer, p53 overexpression was found in 26 tumors (62%), and 15(36%) had high grade staining. Neither the presence nor the degree of expression correlated with time to progression or time to death. This series suggests that p53 gene inactivation is rare in primary prostatic tumors, not essential to the development of prostate cancer metastases, and of limited use as a prognostic marker in patients with primary or metastatic disease. Another gene or genes on chromosome 17p may be involved in prostate cancer progression.
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Affiliation(s)
- J D Brooks
- Department of Urology, Johns Hopkins Medical Institutions, Baltimore, Maryland 21287-2101, USA
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Abstract
The authors report a case of glomus tumor originating within the lumbar spine. Glomus tumors of intraosseous origin are rare, with the only case reported in the spine arising in the sacrum. The patient presented with the solitary complaint of radiating back pain that resolved postoperatively. The histopathological and radiographic findings are reviewed. To the authors' knowledge, this represents the first case report of a glomus tumor of the spine originating above the sacrum.
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Affiliation(s)
- J C Robinson
- Department of Neurosurgery, Bowman Gray School of Medicine of Wake Forest University, Winston-Salem, North Carolina, USA
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Coric D, Branch CL, Wilson JA, Robinson JC. Arteriovenous fistula as a complication of C1-2 transarticular screw fixation. Case report and review of the literature. J Neurosurg 1996; 85:340-3. [PMID: 8755766 DOI: 10.3171/jns.1996.85.2.0340] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.6] [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: 02/02/2023]
Abstract
A case is reported of a vertebral artery-to-epidural venous plexus fistula as a complication of posterior atlantoaxial facet screw fixation. The use of transarticular screws to stabilize the C1-2 joint has become an increasingly popular fixation technique, most notably for atlantoaxial instability due to trauma or rheumatoid disease. Despite the fact that this approach is technically challenging, there have been few reports of complications associated with C1-2 transarticular fixation. Although damage to the vertebral artery is a documented hazard of transarticular fixation at this level, a symptomatic arteriovenous fistula resulting from the procedure has not been described previously. The etiology, presentation, and treatment of this unusual complication are discussed.
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Affiliation(s)
- D Coric
- Department of Neurosurgery, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
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Crawford KS, Gange SJ, Gabelt BT, Heideman W, Robinson JC, Hubbard WC, Kaufman PL. Indomethacin and epinephrine effects on outflow facility and cyclic adenosine monophosphate formation in monkeys. Invest Ophthalmol Vis Sci 1996; 37:1348-59. [PMID: 8641838] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
PURPOSE To investigate the effect of indomethacin inhibition of prostanoid production on the epinephrine-stimulated increase in outflow facility and cyclic adenosine monophosphate (cAMP) production in the anterior segment of the monkey eye. METHODS Topical indomethacin was given 1 hour before the intracameral administration of epinephrine to living cynomolgus monkeys. Outflow facility was measured for 45 to 60 minutes, beginning 3 hours after epinephrine administration, by two-level constant pressure perfusion of the anterior chamber. Cyclic adenosine monophosphate formation was measured in cell membranes isolated from rhesus monkey ciliary muscle, ciliary processes, trabecular meshwork, and iris in the presence of forskolin, indomethacin, epinephrine, or indomethacin and epinephrine combined. RESULTS Three hours after the intracameral administration of 5.5 micrograms epinephrine, facility increased by approximately 40%, a putatively maximal response, at which time the intracameral epinephrine concentration was approximately 15 microM. Pretreatment with topical indomethacin produced a dose-dependent inhibition of epinephrine's facility-increasing effect; the maximum inhibition of 50% to 70% occurred at an indomethacin dose of 50 to 125 micrograms. Doubling the indomethacin dose (250 micrograms) produced no further inhibition, whereas a fivefold larger epinephrine dose (27.5 micrograms) did not overcome the inhibition. Forskolin and epinephrine both stimulated cAMP production in vitro, whereas [indomethacin] > or = 10(-4) M partially inhibited both basal and epinephrine-stimulated cAMP production in all four tissues. CONCLUSIONS Approximately half of the epinephrine-induced facility increase is inhibited by indomethacin, but it is unclear whether the indomethacin-inhibitable fraction is mediated by epinephrine-stimulated prostanoid production or release.
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Affiliation(s)
- K S Crawford
- Department of Ophthalmology, University of Wisconsin, Madison 53792-3220, USA
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