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Cohen CJ, Iwane MK, Palensky JB, Levin DL, Meagher KJ, Frost KR, Mayer KH. A national HIV community cohort: design, baseline, and follow-up of the AmFAR Observational Database. American Foundation for AIDS Research Community-Based Clinical Trials Network. J Clin Epidemiol 1998; 51:779-93. [PMID: 9731927 DOI: 10.1016/s0895-4356(98)00043-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
This article describes the design, methodology, baseline distributions, and general follow-up characteristics of the American Foundation for AIDS Research (AmFAR) National Observational Database (ODB) Project including the benefits and limitations of collecting information on a large simple cohort in the HIV community setting. The study prospectively followed 15,611 HIV-positive men and women and collected longitudinal and cross-sectional data on demographics, medical conditions, drug therapies, laboratory parameters, and survival. Participants were followed between October 1990 and December 1993 by 252 community-based sites coordinated by 22 centers in the Community-Based Clinical Trials Network (CBCT Network) throughout the United States (including Puerto Rico) and Toronto, Canada. The ODB provided quantitative information on a national level needed to track the HIV epidemic and plan clinical trials conducted through the Network, and to provide sites with local databases to monitor patients and facilitate access to therapies in clinical trials. Overall, the ODB contains information on 1,925 women (12%) and 13,686 men (88%), 60% white, 20% African American, 17% Latino/Hispanic, with 56,254 baseline and follow-up forms, a median follow-up of about 12 months, a 16% loss-to-follow-up, and an 11% mortality rate. AmFAR plans to place the ODB in the public domain.
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Frost KR, Bellman P, Cohen CJ, Currier J, Dobkin J, El-Sadr W, Holodniy M, Leonard A, Merrick S, Pinsky L, Rubin D, Vaughn A, Saag M. Controversies in AIDS treatment. Proceedings from CME conference sponsored by Cornell University Medical College and the American Foundation for AIDS Research (AmFAR). November 8, 1997. Question and answer session. AIDS Patient Care STDS 1998; 12:557-66. [PMID: 15462007 DOI: 10.1089/apc.1998.12.557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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78
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Frost KR, Bellman P, Cohen CJ, Currier J, Dobkin J, El-Sadr W, Holodniy M, Leonard A, Merrick S, Pinsky L, Rubin DS, Saag M, Vaughn A. Controversies in AIDS treatment. Proceedings from CME conference sponsored by Cornell University Medical College and the American Foundation for AIDS Research (AmFAR). November 8, 1997. Faculty roundtable discussion. AIDS Patient Care STDS 1998; 12:543-55. [PMID: 15462006 DOI: 10.1089/apc.1998.12.543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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79
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Cohen CJ. Approaches to salvage therapy. AIDS Patient Care STDS 1998; 12:537-41. [PMID: 15462005 DOI: 10.1089/apc.1998.12.537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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80
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Warmke JW, Reenan RA, Wang P, Qian S, Arena JP, Wang J, Wunderler D, Liu K, Kaczorowski GJ, Van der Ploeg LH, Ganetzky B, Cohen CJ. Functional expression of Drosophila para sodium channels. Modulation by the membrane protein TipE and toxin pharmacology. J Gen Physiol 1997; 110:119-33. [PMID: 9236205 PMCID: PMC2233785 DOI: 10.1085/jgp.110.2.119] [Citation(s) in RCA: 175] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/1996] [Accepted: 05/14/1997] [Indexed: 02/04/2023] Open
Abstract
The Drosophila para sodium channel alpha subunit was expressed in Xenopus oocytes alone and in combination with tipE, a putative Drosophila sodium channel accessory subunit. Coexpression of tipE with para results in elevated levels of sodium currents and accelerated current decay. Para/TipE sodium channels have biophysical and pharmacological properties similar to those of native channels. However, the pharmacology of these channels differs from that of vertebrate sodium channels: (a) toxin II from Anemonia sulcata, which slows inactivation, binds to Para and some mammalian sodium channels with similar affinity (Kd congruent with 10 nM), but this toxin causes a 100-fold greater decrease in the rate of inactivation of Para/TipE than of mammalian channels; (b) Para sodium channels are >10-fold more sensitive to block by tetrodotoxin; and (c) modification by the pyrethroid insecticide permethrin is >100-fold more potent for Para than for rat brain type IIA sodium channels. Our results suggest that the selective toxicity of pyrethroid insecticides is due at least in part to the greater affinity of pyrethroids for insect sodium channels than for mammalian sodium channels.
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Freedberg KA, Cohen CJ, Barber TW. Prophylaxis for disseminated Mycobacterium avium complex (MAC) infection in patients with AIDS: a cost-effectiveness analysis. JOURNAL OF ACQUIRED IMMUNE DEFICIENCY SYNDROMES AND HUMAN RETROVIROLOGY : OFFICIAL PUBLICATION OF THE INTERNATIONAL RETROVIROLOGY ASSOCIATION 1997; 15:275-82. [PMID: 9292586 DOI: 10.1097/00042560-199708010-00005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVE To determine the effectiveness and costs of prophylaxis for disseminated Mycobacterium avium complex (MAC) infection in patients with AIDS. DESIGN A decision analysis model was constructed to compare rifabutin (300 mg/day), azithromycin (1200 mg/week), and clarithromycin (500 mg twice per day) with no prophylaxis. Sensitivity analysis was done on all model parameters, including initial CD4 count for beginning prophylaxis. SETTING The setting was hypothetical for the cost-effectiveness model. Clinical data were taken from published prospective randomized controlled trials. MAIN OUTCOME MEASURES Outcomes were measured in terms of projected life expectancy, quality-adjusted life expectancy, direct medical costs, and cost-effectiveness in U.S. dollars per quality-adjusted life-year saved ($/QALY). RESULTS For patients with AIDS and those having CD4 counts <75 cells/mm3, azithromycin, clarithromycin, and rifabutin prophylaxis increased lifetime per person MAC-related costs by $994, $2,117, and $2,185 U.S., respectively. Quality-adjusted life expectancy increased from 1.6068 QALYs to between 1.6186 and 1.6255 QALYs. The cost-effectiveness ratios were $58,200, $116,000, and $179,100/QALY saved for azithromycin, clarithromycin, and rifabutin prophylaxis, respectively, each compared with no prophylaxis. Results were most dependent on the annual cost of prophylaxis, the initial CD4 count when starting prophylaxis, and any survival benefit with prophylaxis. For each type of prophylaxis, strategies beginning with CD4 counts <25 or 50 cells/mm3 were substantially more cost-effective than those beginning in patients with higher CD4 counts. CONCLUSIONS MAC prophylaxis is likely to cost society an additional $99 to $219 million U.S. per 100,000 patients treated. In the context of Centers for Disease Control and Prevention (CDC) recommendations to use prophylaxis in patients with CD4 counts <75 cells/mm3, azithromycin represents the best value and is most cost-effective when used in patients with CD4 counts <25 cells/mm3.
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82
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Cohen CJ. Tamoxifen and endometrial cancer: tamoxifen effects on the human female genital tract. Semin Oncol 1997; 24:S1-55-S1-64. [PMID: 9045317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
An association between the administration of tamoxifen in patients with breast cancer and the development of endometrial cancer has been suggested in a number of clinical studies, none of which was designed prospectively to study the endometrial effects of tamoxifen. Because of this observation, some have equated tamoxifen with "estrogen," and inferences have been drawn about its possible carcinogenic effect. This presentation analyzes the effect of tamoxifen on the lower genital tract in the adult human female, compares it with the effect of estradiol, and compares and contrasts the effect of these substances on the end organs of laboratory animals, cell lines, transplants, and their differential effects in the human uterus, cervix, and vagina. Of note is the fact that in patients who have not had breast cancer, there is no report of the development of endometrial cancer in women taking tamoxifen. Careful monitoring of this population may define with better precision the mechanism of action of tamoxifen as well as the process of oncogenesis in the human endometrium.
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83
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Cohen CJ, Hellinger JA, Day J, Salitsky N, Shevitz A, Zackin R, DeGruttola V. Lack of effect of cimetidine on lymphocyte subsets in patients infected with human immunodeficiency virus type 1. Clin Infect Dis 1996; 23:1049-54. [PMID: 8922801 DOI: 10.1093/clinids/23.5.1049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Cimetidine, widely used for peptic ulcer disease, blocks type 2 histamine receptors present on immune cells, including T cells, B cells, and monocytes. As an earlier published study showed evidence of increases in CD4 cell counts due to this drug, we conducted a randomized, placebo-controlled, 8-week trial of oral cimetidine (400 mg p.o. t.i.d.) in a study involving 182 patients infected with human immunodeficiency virus (HIV). Overall, cimetidine-treated patients had a decline in CD4+ cell counts that was no different from the decline for placebo-treated persons, neither during the first 8 weeks of the trial (mean drop, 7.1% [standard error, 12.1-1.8] vs. 6.7% [standard error, 11.6-1.5]) nor during the subsequent 8 weeks of open-label administration of cimetidine. No differences were evident between the treatment groups in terms of the percentage reactive to p24 antigen at baseline, and p24 antigen concentrations did not change from baseline to the end of week 8. In summary, cimetidine is well tolerated by HIV-infected individuals but alters neither CD4+ cell counts nor at least one quantitative measure of viral load, HIV p24 antigen levels.
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Lu HK, Fern RJ, Luthin D, Linden J, Liu LP, Cohen CJ, Barrett PQ. Angiotensin II stimulates T-type Ca2+ channel currents via activation of a G protein, Gi. THE AMERICAN JOURNAL OF PHYSIOLOGY 1996; 271:C1340-9. [PMID: 8897841 DOI: 10.1152/ajpcell.1996.271.4.c1340] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Angiotensin II (ANG II) is the most potent and the most physiologically important stimulator of aldosterone synthesis and secretion from the adrenal zona glomerulosa. Because steroidogenesis by adrenal glomerulosa (AG) cells is mediated in part by Ca2+ influx through T- and L-type Ca2+ channels, we evaluated whether T-type Ca2+ channels are regulated by ANG II. We observe that ANG II enhances T-type Ca2+ current by shifting the voltage dependence of channel activation to more negative potentials. This shift is transduced by the ANG II type 1 receptor. The effect of the hormone is not mediated by Ca2+/calmodulin-dependent protein kinase II (CaMKII) as it is not prevented by CaMKII(281-302), a peptide inhibitor of the catalytic region of the kinase. Rather, this shift is mediated by the activation of a G protein, Gi, because it is abolished by cell pretreatment with pertussis toxin and by cell dialysis with a monoclonal antibody generated against recombinant Gi alpha. This effect of ANG II on T-type Ca2+ channels should increase Ca2+ entry in AG cells at physiologically relevant voltages and result in a sustained increase in aldosterone secretion.
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85
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Cohen CJ, Ripley D. Managed care in gynecologic oncology. Curr Opin Obstet Gynecol 1996; 8:325-8. [PMID: 8875047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We review the recent literature on managed care and its application to gynecologic oncology. Although the literature is limited, we discuss professional agreement contracts, the role of primary care physicians and specialists in gynecologic cancer screening, changes in health care distribution, changes in physician-patient relationships, and cancer research.
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Abstract
Risk factors for endometrial cancer include obesity, nulligravidity, late menopause, and anovulatory states. Although diabetes is highly associated with endometrial cancer, hypertension is not an independent variable when correction is made for other factors. Exogenous estrogen increases the risk by at least four times, and smoking is a significant factor. Screening of asymptomatic women may be useful among high risk patients. In addition, racial influence on virulence has recently been identified. Most recurrences of endometrial cancer are identified within 3 years of initial diagnosis. Predictors include ploidy, histologic grade, histologic type, receptor status, and stage. Treatment of recurrence is individualized based on tumor location and receptor status and may involve surgery, radiation therapy, hormonal therapy, or cytotoxic chemotherapy. Tamoxifen has been shown to improve survival among subsets of patients with breast cancer in all stages. A comprehensive literature review and meta-analyses, however, verified an increased risk of endometrial cancer among tamoxifen-treated patients compared with control subjects that may equal the cancer risk from exogenous estrogen exposure. Screening techniques include sonographic assessment of endometrial thickening and vascular patterns, hysteroscopy, and endometrial sampling. A subendometrial cystic proliferation can confuse radiographic evaluation of endometrium, leading to unindicated curettage. A disproportionate incidence of high grade lesions has been reported; however, tamoxifen should not be withheld from patients with breast cancer.
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87
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Dottino PR, Segna RA, Jennings TS, Mandeli JP, Konsker K, Cohen CJ. Pelvic exenteration in gynecologic oncology: Experience at the Mount Sinai Center, 1975-1992. THE MOUNT SINAI JOURNAL OF MEDICINE, NEW YORK 1995; 62:431-5. [PMID: 8692157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Thirty-nine patients underwent pelvic exenteration for gynecologic malignancies at The Mount Sinai Medical Center between 1975 and 1992. Surgical techniques, morbidity, survival, and other variables for patients so treated in two periods, 1975-1984 and 1985-1992, were compared. The primary cancer included squamous cell carcinoma of the cervix, 27; adenocarcinoma of the cervix, 1; squamous cell carcinoma of the vagina, 4; adenocarcinoma of the endometrium, 4; squamous cell carcinoma of the vulva, 2; and adenocarcinoma of the rectum, 1. Median survival was 23.1 months, with a median follow-up of 18 months. Survival was significantly related to status of the lymph nodes (p 0.0004) and surgical margins (p 0.0038). There were two postoperative mortalities, one due to pulmonary embolus and another to myocardial infarction. The ability in the second period analyzed, 1985-1992, to integrate a continent urinary reservoir and supralevator exenteration without colostomy yet not induce increased morbidity or decreased survival, has not been previously reported.
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Barrett PQ, Ertel EA, Smith MM, Nee JJ, Cohen CJ. Voltage-gated calcium currents have two opposing effects on the secretion of aldosterone. THE AMERICAN JOURNAL OF PHYSIOLOGY 1995; 268:C985-92. [PMID: 7733247 DOI: 10.1152/ajpcell.1995.268.4.c985] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Using Ca2+ channel blockers with different specificities for L- and T-type Ca2+ channels, we have investigated the roles of these two channel types in K(+)-induced aldosterone secretion. In whole cell voltage-clamp experiments, the spider toxin omega-agatoxin-IIIA (omega-Aga-IIIA) completely blocks L-type Ca2+ channels but has no effect on T-type Ca2+ channels. In contrast, Ni2+ and 1,4-dihydropyridines block both L- and T-type Ca2+ channels. Secretion induced by 7 mM extracellular K+ concentration ([K+]o) is unaffected by omega-Aga-IIIA but is strongly inhibited by Ni2+ or the 1,4-dihydropyridine, nitrendipine. This suggests that physiological increases in [K+]o stimulate aldosterone secretion primarily by enhancing Ca2+ entry through T-type Ca2+ channels. Surprisingly, secretion induced by 60 mM [K+]o is enhanced by omega-Aga-IIIA or Ni2+ and is inhibited by the L-type Ca2+ channel activator BAY K 8644. Nitrendipine (1 nM) also stimulates such secretion, although higher concentrations are inhibitory (concentration inhibiting 50% of maximal response approximately 30 nM). If extracellular Ca2+ concentration is reduced from 1.25 to 0.5 mM, secretion induced by 60 mM [K+]o is enhanced, and Ni2+ or low nitrendipine become inhibitory. Together, these results that L-type Ca2+ currents can reduce steroidogenesis and that the role of these currents was previously misconstrued because 1,4-dihydropyridines modify secretion by multiple mechanisms. Thus Ca2+ entry can function as a negative modulator of steroid secretion.
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89
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Dottino PR, Segna RA, Jennings TS, Beddoe AM, Cohen CJ. The stapled continent ileocecal urinary reservoir in the surgical management of gynecologic malignancy. Gynecol Oncol 1994; 55:185-9. [PMID: 7959282 DOI: 10.1006/gyno.1994.1275] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Total cystectomy at the time of radical pelvic surgery for gynecologic malignancies is not uncommon. Many techniques have been developed for urinary diversion including the continent ileocecal urinary reservoir. Twenty-nine patients underwent construction of a continent ileocecal urinary reservoir during the reconstructive phase of an exenterative procedure or for the relief of urinary tract fistula between 1990 and 1993. All procedures were performed using the mechanical stapling devices using metal staples. The right and proximal transverse colon were mobilized to a length of 24 cm. The ileum was divided 8 cm proximal to the ileocecal valve and plicated using the stapling technique. The colonic segment was opened on its antimesenteric border and the reservoir was created by stapling in a fashion to reapproximate the distal ends to each other. The ureters were stented and implanted without tunneling. A large Malecot drain was placed in all the pouches for irrigation of the colonic mucosa in the postoperative period. The ileal stoma was fixed to the anterior abdominal wall as was the anterior surface of the pouch. Operative time ranged from 50 to 150 min for the pouch construction. All patients underwent retrograde contrast study of the pouch 7-10 days postoperatively to verify lack of anastomatic leaks. After recovery, all patients successfully self-catheterized the pouch three to five times daily without difficulty. Of the 29 patients, 17 (59%) had received prior radiation as part of therapy. All patients remained continent at the end of observation. One developed a fistula to the perineum after intraoperative placement of 125I seeds on the pelvic wall. One patient developed pouch stones; endoscopic evaluation of this pouch revealed no evidence of stones at the staple lines and metabolic workup demonstrated hypocitremia as the etiology for the stones. Mean reservoir volume was 550 ml. Mean follow-up is 15.8 months; 5 have expired due to recurrent disease and 19 (83%) remain alive. Only two patients have been admitted for urosepsis due to reflux pyelonephritis. The stapled continent ileocecal reservoir offers benefits to patients undergoing total cystectomy. Using the mechanical stapling devices decreases the operative time and has not resulted in stone formation or pouch leakage. The complications of the procedure are acceptable.
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90
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Jennings TS, Dottino PR, Mandeli JP, Segna RA, Kelliher K, Cohen CJ. Growth factor expression in normal peritoneum of patients with gynecologic carcinoma. Gynecol Oncol 1994; 55:190-7. [PMID: 7959283 DOI: 10.1006/gyno.1994.1276] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Both epidermal growth factor receptor (EGFR) and HER-2/neu (neu) have been found to be of prognostic importance in epithelial ovarian and endometrial carcinoma, but alterations in proto-oncogene expression of normal tissues of patients with gynecologic malignancies are unknown. Patients (118) undergoing laparotomy for gynecologic indications (78 ovarian cancer, 11 endometrial cancer, 19 benign gynecologic disease, 10 other cancers) had biopsies of normal peritoneum for quantitative assessment of neu and EGFR concentrations. Patients undergoing exploration for gynecologic malignancy were found to have significantly higher median neu expression in the peritoneal biopsies than patients with benign gynecologic disease (P = 0.002). Most patients in this study were found to have ovarian cancer, and median peritoneal neu expression was found to be significantly higher in patients with ovarian cancer versus benign ovarian masses (P = 0.0008) or any benign gynecologic disease (P = 0.004). No significant alteration of unbound EGFR was found in peritoneal biopsies of any of the groups of patients. No associations were found for a history of breast cancer, presence of ascites, or menopausal status with alteration of neu or EGFR expression in normal peritoneum. These findings of altered expression of neu in normal tissues of patients with ovarian cancer are suggestive of the presence of proto-oncogene alterations in loco-regional tissues of the peritoneum, such as might be seen if a paracrine influence existed between tumor and peritoneal cells. Alternatively, the alterations may represent subtle alterations of proto-oncogene expression of germ-line tissues.
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91
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Bacon RA, Cohen CJ, Lewin DA, Mellman I. Dictyostelium discoideum mutants with temperature-sensitive defects in endocytosis. J Cell Biol 1994; 127:387-99. [PMID: 7929583 PMCID: PMC2120217 DOI: 10.1083/jcb.127.2.387] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We have isolated and characterized temperature-sensitive endocytosis mutants in Dictyostelium discoideum. Dictyostelium is an attractive model for genetic studies of endocytosis because of its high rates of endocytosis, its reliance on endocytosis for nutrient uptake, and tractable molecular genetics. Endocytosis-defective mutants were isolated by a fluorescence-activated cell sorting (FACS) as cells unable to take up a fluorescent marker. One temperature-sensitive mutant (indy1) was characterized in detail and found to exhibit a complete block in fluid phase endocytosis at the restrictive temperature, but normal rates of endocytosis at the permissive temperature. Likewise, a potential cell surface receptor that was rapidly internalized in wild-type cells and indy1 cells at the permissive temperature was poorly internalized in indy1 under restrictive conditions. Growth was also completely arrested at the restrictive temperature. The endocytosis block was rapidly induced upon shift to the restrictive temperature and reversed upon return to normal conditions. Inhibition of endocytosis was also specific, as other membrane-trafficking events such as phagocytosis, secretion of lysosomal enzymes, and contractile vacuole function were unaffected at the restrictive temperature. Because recycling and transport to late endocytic compartments were not affected, the site of the defect's action is probably at an early step in the endocytic pathway. Additionally, indy1 cells were unable to proceed through the normal development program at the restrictive temperature. Given the tight functional and growth phenotypes, the indy1 mutant provides an opportunity to isolate genes responsible for endocytosis in Dictyostelium by complementation cloning.
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92
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Cohen CJ, Bacon R, Clarke M, Joiner K, Mellman I. Dictyostelium discoideum mutants with conditional defects in phagocytosis. J Cell Biol 1994; 126:955-66. [PMID: 7519624 PMCID: PMC2120108 DOI: 10.1083/jcb.126.4.955] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
We have isolated and characterized Dictyostelium discoideum mutants with conditional defects in phagocytosis. Under suspension conditions, the mutants exhibited dramatic reductions in the uptake of bacteria and polystyrene latex beads. The initial binding of these ligands was unaffected, however, indicating that the defect was not in a plasma membrane receptor: Because of the phagocytosis defect, the mutants were unable to grow when cultured in suspensions of heat-killed bacteria. The mutants exhibited normal capacities for fluid phase endocytosis and grew as rapidly as parental (AX4) cells in axenic medium. Both the defects in phagocytosis and growth on bacteria were corrected when the mutant Dictyostelium cells were cultured on solid substrates. Reversion and genetic complementation analysis suggested that the mutant phenotypes were caused by single gene defects. While the precise site of action of the mutations was not established, the mutations are likely to affect an early signaling event because the binding of bacteria to mutant cells in suspension was unable to trigger the localized polymerization of actin filaments required for ingestion; other aspects of actin function appeared normal. This class of conditional phagocytosis mutant should prove to be useful for the expression cloning of the affected gene(s).
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93
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Ertel EA, Warren VA, Adams ME, Griffin PR, Cohen CJ, Smith MM. Type III omega-agatoxins: a family of probes for similar binding sites on L- and N-type calcium channels. Biochemistry 1994; 33:5098-108. [PMID: 8172884 DOI: 10.1021/bi00183a013] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The peptide omega-agatoxin-IIIA (omega-Aga-IIIA) from venom of the funnel web spider Agelenopsis aperta is the only known agent that blocks L-type and N-type Ca channels with equal high potency (IC50 < or = 1 nM). From the same venom, we have purified and sequenced a family of peptides which are homologous to omega-Aga-IIIA but vary over 100-fold in their relative affinity for L-type versus N-type Ca channels. One of these, omega-Aga-IIIB, is 76 amino acids long and identical to omega-Aga-IIIA in 66 positions. We identified two other similar peptides, omega-Aga-IIIC and omega-Aga-IIID, as well as one single amino acid variant of omega-Aga-IIIA and two of omega-Aga-IIIB. The type III omega-agatoxins exhibit similar but distinct activities on voltage-gated Ca channels. omega-Aga-IIIA, omega-Aga-IIIB, and omega-Aga-IIID are nearly indistinguishable in their actions at the insect neuromuscular junction (no effect at 0.1 microM), on atrial T-type Ca channels (no effect at 0.5 microM), and in two assays for synaptosomal Ca channels: they are nearly equipotent inhibitors of 125I-omega-conotoxin GVIA binding to rat brain synaptic membranes (IC50 = 0.17-0.33 nM) and blockers of the K(+)-induced 45Ca2+ influx into chick brain synaptosomes (omega-Aga-IIIB, 1.2 nM; omega-Aga-IIIA, 2.4 nM). In contrast, omega-Aga-IIIA is a better blocker of locust Ca channels (IC50 approximately 10-50 nM) than is omega-Aga-IIIB. Finally, although omega-Aga-IIIA, omega-Aga-IIIB, and omega-Aga-IIID all block atrial L-type Ca channels, omega-Aga-IIIA is over 100-fold more potent. Thus, although type III omega-agatoxins appear to recognize a binding site common to L- and N-type Ca channels, omega-Aga-IIIB and omega-Aga-IIID identify differences between the two channels.
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94
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Ertel EA, Smith MM, Leibowitz MD, Cohen CJ. Isolation of myocardial L-type calcium channel gating currents with the spider toxin omega-Aga-IIIA. J Gen Physiol 1994; 103:731-53. [PMID: 8035161 PMCID: PMC2219219 DOI: 10.1085/jgp.103.5.731] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The peptide omega-agatoxin-IIIA (omega-Aga-IIIA) blocks ionic current through L-type Ca channels in guinea pig atrial cells without affecting the associated gating currents. omega-Aga-IIIA permits the study of L-type Ca channel ionic and gating currents under nearly identical ionic conditions. Under conditions that isolate L-type Ca channel currents, omega-Aga-IIIA blocks all ionic current during a test pulse and after repolarization. This block reveals intramembrane charge movements of equal magnitude and opposite sign at the beginning of the pulse (Q(on)) and after repolarization (Q(off)). Q(on) and Q(off) are suppressed by 1 microM felodipine, saturate with increasing test potential, and are insensitive to Cd. The decay of the transient current associated with Q(on) is composed of fast and slow exponential components. The slow component has a time constant similar to that for activation of L-type Ca channel ionic current, over a broad voltage range. The current associated with Q(off) decays monoexponentially and more slowly than ionic current. Similar charge movements are found in guinea pig tracheal myocytes, which lack Na channels and T-type Ca channels. The kinetic and pharmacological properties of Q(on) and Q(off) indicate that they reflect gating currents associated with L-type Ca channels. omega-Aga-IIIA has no effect on gating currents when ionic current is eliminated by stepping to the reversal potential for Ca or by Cd block. Gating currents constitute a significant component of total current when physiological concentrations of Ca are present and they obscure the activation and deactivation of L-type Ca channels. By using omega-Aga-IIIA, we resolve the entire time course of L-type Ca channel ionic and gating currents. We also show that L- and T-type Ca channel ionic currents can be accurately quantified by tail current analysis once gating currents are taken into account.
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Cohen CJ, Jennings TS. Screening for ovarian cancer: the role of noninvasive imaging techniques. Am J Obstet Gynecol 1994; 170:1088-94. [PMID: 8166191 DOI: 10.1016/s0002-9378(94)70102-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In spite of diagnostic and therapeutic improvements the Surveillance Epidemiology and End Results Program data suggest that the overall cure rate for patients with ovarian cancer is 39%. Because of the dramatic difference in cure between patients with local disease (80% to 90%) and those with distant disease (15% to 25%), screening to find early ovarian cancer or its precursors is desirable. Transvaginal ultrasonography is the most efficient, accurate, and least expensive of the imaging modalities (transabdominal ultrasonography, computed tomography, magnetic resonance imaging, radioimmunoscintigraphy) for this purpose. To date, 10,000 women have been screened in three large programs; 11 cancers were detected (10 stage I, one occult stage IIIB) and all have apparently been cured. Doppler flow imaging and morphology index values improve the accuracy of transvaginal ultrasonography. A cost analysis suggests that screening costs are not yet less than treatment costs if there is to be universal screening of 27 million women at risk in the United States. However, for a population with a lifetime risk for ovarian cancer of 1%, screening will save five lives per 2000 patients screened.
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Beddoe AM, Dottino PR, Cohen CJ. Phase II trial of etoposide, carboplatin, and ifosfamide as salvage therapy in advanced ovarian carcinoma. THE MOUNT SINAI JOURNAL OF MEDICINE, NEW YORK 1993; 60:311-6. [PMID: 8232377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A phase II study combining etoposide with carboplatin and ifosfamide as salvage therapy in advanced ovarian cancer was undertaken. Objective responses were achieved in 37.5% of 16 evaluable patients with a mean progression-free interval of 8.6 months. Stable disease was present in 25% of patients; in 37.5% of patients the disease progressed on salvage. Based on original response to front-line therapy, patients were classified as being platinum-sensitive (group I) or platinum-refractory (group II). Clinical response to salvage therapy was seen in 44.5% of group I patients, but in only 28.6% of group II patients. This difference was not statistically significant. When a more precise definition of platinum sensitivity was applied, clinical responses were seen in 54.5% of group I patients, but no responses were noted among group II patients (p < 0.05). Platinum sensitivity appeared to be an important factor in achieving a response with this regimen. This combination was well tolerated, myelotoxicity being the dose-limiting toxicity encountered. No life-threatening, nonhematologic toxicities were seen. One death occurred secondary to nadir sepsis. The combination of etoposide, carboplatin, and ifosfamide is an active salvage regimen in patients with advanced ovarian carcinoma; however, severe myelotoxicities and inability to produce long-term responses underscore the need for continued trials to find a more durable salvage regimen.
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Segna RA, Dottino PR, Mandeli JP, Konsker K, Cohen CJ. Secondary cytoreduction for ovarian cancer following cisplatin therapy. J Clin Oncol 1993; 11:434-9. [PMID: 8445417 DOI: 10.1200/jco.1993.11.3.434] [Citation(s) in RCA: 135] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
PURPOSE This study was undertaken to evaluate the efficacy of secondary surgical cytoreduction in the management of ovarian cancer. PATIENTS AND METHODS The cases of 100 patients with recurrent or progressive epithelial ovarian cancer whose initial treatment had been cytoreduction followed by cytotoxic therapy with a cisplatin-based regimen were reviewed. All 100 patients underwent surgery, after recurrence or progression was documented preoperatively, by gynecologic oncologists at the Mount Sinai Medical Center, New York, NY, between 1980 and 1991 with the intention of performing radical tumor reduction. RESULTS Sixty-one patients had a secondary cytoreduction that left residual disease less than 2 cm in diameter. The median survival, determined from the date of the secondary cytoreduction to the date of death or last follow-up, is 27.1 months in the optimally treated group and 9.0 months for the 39 patients whose surgery was suboptimal (P = .0001). Other variables associated with statistically significant longer survival, and a significantly higher probability of achieving a successful secondary cytoreduction, included age < or = 55 years at the time of secondary cytoreduction, interval from initial diagnosis to secondary cytoreduction of more than 12 months, residual disease at initial staging laparotomy of less than 2 cm, and a complete clinical response to a cisplatin-based front-line regimen. Multivariate analysis confirms the survival benefit provided by a successful secondary cytoreduction when adjusted for the above variables. There was one postoperative mortality. Ten percent of the successfully cytoreduced patients and 18% of the unsuccessfully cytoreduced patients experienced some degree of postoperative morbidity. CONCLUSION These data justify the performance of secondary cytoreductive surgery for patients who develop gross recurrent or progressive ovarian cancer following cisplatin therapy.
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Segna RA, Dottino PR, Jennings TS, Cohen CJ. Feasibility of intraoperative administration of chemotherapy for gynecologic malignancies: assessment of acute postoperative morbidity. Gynecol Oncol 1993; 48:227-31. [PMID: 8428695 DOI: 10.1006/gyno.1993.1038] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
In order to assess the acute effects of the intraoperative administration of intraperitoneal (IP) carboplatin with and without intravenous (IV) doxorubicin in patients with gynecologic malignancies, 25 patients were treated at the conclusion of their surgical procedure. Twenty-three had epithelial ovarian cancer and 2 had advanced endometrial cancer. Twelve patients received IP carboplatin and IV doxorubicin at the conclusion of their primary cytoreduction. The remaining 13 received IP carboplatin alone and consisted of 4 reassessment laparotomies for ovarian cancer, 7 secondary cytoreductions, 1 minilaparotomy for the placement of an IP catheter, and 1 second-look laparoscopy. The median age of the 25 patients was 59 years. Eight patients underwent bowel resections with anastomoses; 2 had ureteral resections and ureteroneocystostomies, 1 required a splenectomy, and 1 underwent a partial hepatic resection. There were no mortalities. Three of the 13 patients who received the IP carboplatin alone had postoperative fevers with no infectious source, which did not delay discharge. No other morbidity was noted in this group. However, 7 patients who received IV doxorubicin along with the IP carboplatin developed severe leukopenia requiring antimicrobial and colony-stimulating factor support. One patient required reexploration for postoperative hemorrhage and also developed a pulmonary embolus. One woman developed postoperative pneumonia. The median hospital stay for the 25 patients was 9 days. Intraoperative chemotherapy can be administered with tolerable immediate adverse effects.
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Deligdisch L, Kerner H, Cohen CJ, Dargent D, Gil J. Morphometric differentiation between responsive tumor cells and mesothelial hyperplasia in second-look operations for ovarian cancer. Hum Pathol 1993; 24:143-7. [PMID: 8432510 DOI: 10.1016/0046-8177(93)90292-o] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We developed a procedure based on computerized image analysis to establish objective criteria for the differential diagnosis between mesothelial hyperplasia and cancer in peritoneal tissue samples obtained at second-look operations for ovarian cancer. The tumor tissue after chemotherapy was classified as "nonresponsive" if it was found by histologic criteria to be roughly similar to the tumor before chemotherapy and as "responsive" if it was found to be different (small clusters of bland-looking cells with no mitotic activity). Eighty-five samples of tissue had been classified previously by a pathologist into one of the four following groups: ovarian tumor prior to chemotherapy, "responsive" tumor, "nonresponsive" tumor, or mesothelial hyperplasia. Cell profiles of the tissue samples were studied by computerized image analysis using 21 morphometric descriptors derived from the manual tracings of tumor nuclei, including nuclear perimeter, nuclear area, maximal chord, circularity factor, and standard deviations of these descriptors. Size distribution curves of nuclear areas and maximal chords were included in the analysis. A multivariate discriminant analysis confirmed the separation into the four diagnostic groups, accomplished with consideration of the physical descriptors alone, except for some overlapping between groups 1 and 3. The separation between carcinoma and mesothelial hyperplasia was clear in all cases.
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100
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Plaxe SC, Dottino PR, Cohen CJ. Gynecologic malignancy presenting as hernia. Am Fam Physician 1993; 47:51, 54, 57. [PMID: 8418586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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