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Biomedical subjects

C Cohen

Publications and source records attributed to C Cohen.

At least 505 records · Page 28Linked to original sources
PubMedDate not supplied

Structure of co-crystals of tropomyosin and troponin.

Troponin, a Ca2+-sensitive complex, regulates the motions of tropomyosin on the thin filaments in many muscles. It has three subunits, each with a different architecture and function: TnC binds Ca2+; TnI binds to actin and inhibits contraction; and TnT binds one complex to each tropomyosin molecule. The troponin complex has an elongated shape with TnC and TnI forming a globular 'head' region and TnT a long (approximately 160 A) 'tail'. TnT binds to two widely separated regions of tropomyosin: the head region of the complex is near Cys 190 of tropomyosin and the tail region is near the overlapping joint that links the tropomyosin molecules into filaments. Here we report the X-ray structure determination at 17 A resolution of glutaraldehyde-treated tropomyosin crystals in which native troponin complex or fragments of TnT have been bound. Our results show that the amino-terminal tail end of TnT spans the head-to-tail joint of the tropomyosin filaments, and that the 'head' region of the whole troponin complex binds approximately 200 A away near residues 150-180 of the tropomyosin molecule.

Animals↗
PubMedDate not supplied

Does the density of lymphatic vascular space invasion affect the prognosis of stage Ib and IIA node negative carcinoma of the cervix?

Lymphatic vascular space invasion (LVSI) has been noted as a poor prognostic factor in many tumors. In some studies of carcinoma of the cervix, LVSI has been demonstrated to be independent of other prognostic factors. The aim of this study is to evaluate if, by a simple quantitative technique, the density of lymphatic invasion could be correlated with the risk of recurrence in node negative early stage carcinoma of the cervix. We analyzed the pathology and clinical course of 71 consecutive patients with stage IB and IIA carcinoma of the cervix treated primarily by radical hysterectomy and pelvic lymphadenectomy. All cases had negative nodes and adequate surgical margins. There were 67 patients suitable for evaluation. Tumour type, grade, stage and the dimensions of the tumor were recorded. The density of LVSI was categorized as absent (45%), mild (15%), moderate (33%) or severe (7%) depending on the number of lymphatic vascular spaces involved per high power field in the worst affected slide. The patients were followed for 2-8(1/2) years with a mean follow up of 4 years and 2 months. There were 13 recurrences and 7 deaths. All recurrences occurred in less than 2 years after surgery. The risk of recurrence was 40% for patients with extensive LVSI, 32% for moderate, 30% for mild and 3% if LVSI was absent. Only the presence of LVSI was associated with an increased risk of recurrence. The density of lymphatic invasion as represented by the number of lymphatic spaces occupied on the worst histological slide offered no further clinically useful information.

Adult↗
PubMedDate not supplied

Effects of various doses of estradiol on chlamydial genital infection in ovariectomized guinea pigs.

The effect of various doses of estradiol on genital tract infection by the chlamydial agent of guinea pig inclusion conjunctivitis (GPIC) was investigated in ovariectomized guinea pigs. Prolongation of infection, as determined by chlamydial inclusion counts of cells in Giemsa-stained smears of vaginal scrapings, was observed in animals receiving daily doses of 1.0, 10.0, 100.0, or 1000 micrograms of estradiol. In contrast to controls, ascending infection resulting in endometritis was found in animals receiving doses of greater than or equal to 1.0 microgram of estradiol per day. Response to estradiol treatment was reflected in an increase in cervical-uterine wet weight and uterine wall thickness. No differences were observed in time of appearance of antibody titers to GPIC in serum, but a delay in appearance of IgA antibody to GPIC in genital secretions was found in estradiol-treated animals receiving doses of greater than or equal to 1.0 microgram per day.

Animals↗
PubMedDate not supplied

Absence of progesterone effects on chlamydial genital infection in female guinea pigs.

The effect of progesterone alone and in combination with estradiol was investigated in ovariectomized and gonadally intact female guinea pigs infected with the chlamydial agent of guinea pig inclusion conjunctivitis (GPIC). The course of the infection, as determined by the percentage of cells with GPIC (chlamydia) inclusions in Giemsa-stained vaginal scrapings, was not affected in animals receiving 5.0 mg of progesterone daily. Progesterone had no influence on the enhancement of infection by estradiol. In comparison with sesame oil-treated controls, infection was prolonged by four to six days (P less than .05) in animals receiving a combination of 5.0 mg of progesterone plus 1.0 microgram of estradiol or 1.0 microgram of estradiol alone each day. In ovariectomized animals, estradiol delayed the appearance of IgA antibody in genital secretions, whereas progesterone alone had no effect. Guinea pigs treated with estradiol or progesterone plus estradiol manifested an acute endometritis not observed in animals treated with progesterone alone or in controls receiving sesame oil. Although cervical ectopy, analogous to that seen in women with high levels of progesterone, was identified by histopathology in animals treated with progesterone, no enhancement of the chlamydial infection was observed.

Animals↗
PubMedDate not supplied

Density differences in the spermatozoa of normozoospermic, asthenozoospermic and oligo-asthenozoospermic males.

The spermatozoa densities of the ejaculates obtained daily for five days from infertile males were compared to the spermatozoa densities of the ejaculates obtained from normozoospermic donors. The density distribution of the spermatozoa was established on Percoll columns of discontinuous densities. The density dispersion patterns of five consecutive days from each donor within a donor group were used to establish the main, daily density dispersion patterns. The five, daily, mean dispersion patterns were used to create 3-dimensional graphs of density dispersion variations. The 3-dimensional graphs from the infertile male groups show negligible daily variations as compared to that of the healthy males. The absence of wide daily variations is suggested to be considered as a sign of faulty epididymal functioning.

Centrifugation, Density Gradient↗
PubMedDate not supplied

American Cancer Society guidelines for the early detection of cancer: update of early detection guidelines for prostate, colorectal, and endometrial cancers. Also: update 2001--testing for early lung cancer detection.

Updates to the American Cancer Society (ACS) guidelines regarding screening for the early detection of prostate, colorectal, and endometrial cancers, based on the recommendations of recent ACS workshops, are presented. Additionally, the authors review the "cancer-related check-up," clinical encounters that provide case-finding and health counseling opportunities. Finally, the ACS is issuing an updated narrative related to testing for early lung cancer detection for clinicians and individuals at high risk of lung cancer in light of emerging data on new imaging technologies. Although it is likely that current screening protocols will be supplanted in the future by newer, more effective technologies, the establishment of an organized and systematic approach to early cancer detection would lead to greater utilization of existing technology and greater progress in cancer control.

Colorectal Neoplasms↗
PubMedDate not supplied

Immune responses to a recombinant human immunodeficiency virus type 1 (HIV-1) gpl60 vaccine among adults with advanced HIV infection. Massachusetts gp160 Working Group.

OBJECTIVE: To assess immunogenicity of recombinant human immunodeficiency virus type 1 (HIV-1) envelope vaccine (rgp160) in late HIV infection. STUDY DESIGN/METHODS: HIV-infected volunteers (n = 142), with CD4+ T lymphocyte counts of <400/mm3, were enrolled in a dose-comparison, open-label trial with stratification by CD4+ cell count, randomization to a primary series at two dose levels, and a sub-group receiving interferon-gamma (IFN-gamma) as an adjuvant. Subjects received booster doses of vaccine over a follow-up period of 18-28 months. RESULTS: At 6 and 12 months, 36% and 38% of participants, respectively, had new or augmented antibody titers (> or =4-fold increase) against one or more gpl60 epitopes (C1, V3, C41, 448C). Delayed-type hypersensitivity (DTH) to intradermal gpl60, initially not present in any participant, developed after immunization in 41%, with higher prevalence in participants receiving the lower dose of vaccine. Both antibody and skin test responses occurred in 20-25% of vaccine recipients. Virtually all antibody and skin test responses occurred in participants with initial CD4+ cell counts of >100 cells/mm3. IFN-gamma had no significant effect on immune response. Immunization was well tolerated. Trends in CD4+ cell count, clinical events, and laboratory findings correlated with baseline CD4+ T lymphocyte count stratum and not with immunization regimen. Opportunistic conditions occurred at expected rates. Viral load trends (p24 antigen in all participants and viral RNA by reverse transcription-polymerase chain reaction in a subset of 26 participants) did not correlate with immunization regimen. CONCLUSION: Immunization of patients with advanced HIV infection with rgpl60 resulted in new and augmented humoral and DTH responses, without unexpected significant adverse events or evident clinical benefits attributable to immunization.

AIDS Vaccines↗
PubMedDate not supplied

What support do caregivers of elderly want? Results from the Canadian Study of Health and Aging.

The aim of this paper is to document interest in support strategies among caregivers of elderly persons. We used data from the Canadian Study of Health and Aging caregiver questionnaire which included 43 informal caregivers of elderly persons living with dementia and 145 informal caregivers of elderly persons not living with dementia. While the study assessed interest in attending support groups (10.4%), receiving telephone support from either a professional (44.9%) or a fellow caregiver (41.0%), receiving a newsletter (40.5%), receiving volunteer support (24.2%), and interest in support via computer (14.8%), there were no significant differences between the two groups with regard to interest in any of the support services. Implications for program delivery are discussed. Planners may want to consider adding telephone support and newsletters to other supports already available for caregivers.

Adult↗
PubMedDate not supplied

Expression of progranulin and the epithelin/granulin precursor acrogranin correlates with neoplastic state in renal epithelium.

BACKGROUND: Current traditional pathological parameters, including staging and grading, are not sufficient in predicting outcome in patients with renal cell carcinoma (RCC). Acrogranin is an epithelial growth factor and has been demonstrated to play a role in teratocarcinogenesis and tumorigenesis. The aim of this study was to examine levels of acrogranin in renal cancer. MATERIALS AND METHODS: Western blot analysis was performed on renal tissue protein lysates. In addition, immunohistochemical (IHC) analysis of acrogranin expression was conducted on tissue sections of various histological types and grades of RCC. RESULTS: Western analysis showed that acrogranin levels were low in benign renal tissue and increased in malignant renal tissue. In addition, IHC revealed that high-grade RCC exhibited higher levels of expression than low-grade RCC and normal tissue. CONCLUSION: These data suggest that acrogranin may be a functional important growth factor in RCC and may be a potential molecular marker for high-grade RCC.

Blotting, Western↗
PubMedDate not supplied

Endocrine tumors of the duodenum. A study of 55 cases relative to clinicopathological features and hormone content.

BACKGROUND/AIMS: Study of prognosis of duodenal endocrine tumors. METHODOLOGY: Retrospective study concerned 55 duodenal endocrine tumors discovered in biopsy or surgical specimens. Follow-up records available for 49 patients indicated that inconspicuous associated clinical manifestations were often found subsequently. Seven patients were classified as Zollinger-Ellison syndrome and seven as multiple endocrine neoplasia (6 MEN I and 1 MEN II). RESULTS: Tumors were small (mean 1.28cm) and located preferentially in the first and second part of the duodenum. Fifty-four were well-differentiated and one poorly differentiated. Immunochemistry revealed 30 G-cell tumors (54.6%), 15 D-cell (27.3%), two plurihormonal (EC cell and G cell), and one GRH-cell, whereas seven could not be classified. Fifteen patients died (five in relation to their disease). Twenty-one had metastases (liver, nodes, lung), eight of whom are still alive. CONCLUSIONS: Eighty-eight percent of duodenal endocrine tumors were gastrinomas, small plurifocal tumors and somatostatinomas preferentially located in the ampullar region and diagnosed because of hematemesis or icterus. Size is an important prognostic factor in determining whether surgery is required. The prognosis is better for D- and G-cell tumors than pancreatic endocrine tumors. Duodenal endocrine tumors in multiple endocrine neoplasia have a good prognosis, but can be associated with pancreatic plurihormonal tumors and metastases.

Adolescent↗
PubMedDate not supplied

[Sex crimes and forensic sexology: analytic study].

Most victims of sexual violence tended to at the IML (Forensic Medicine Institute) are female (94.14%) and predominantly under 18 years of age (72.39%). 60.67% filed a complaint for rape. Out of these cases, 44.63% presented a complete hymen and only in 13.30% of the cases a characterized rape was attested to. 21.38% filed a complaint for seduction. Out of these, 78.05% were between 14 and 18 years of age, and 67.18% of them presented their hymens with non-recent ruptures. In only 9.37% of the complaints for seduction the hymen presented recent ruptures. The cases with complaints of libidinous acts other than carnal conjunction represented 17.95%, predominantly male (56.65%) and under 14 years of age (83.33%). The complaints could be confirmed in only 30% of the cases. 91.83% were anal coitus. As for the time elapsed between the assault and the examination, 11.20% showed up within the first 24 hours; 44.79% within 1 to 7 days; 8.07% within 7 to 15 days and 30.21% after 15 days. In short, just about half of the cases showed up for examination in the first week. Therefore, the authors conclude that there is a low positiveness in the examinations, related to several aspects such as the small percentage of victims that seek the IML in time, the lack of traces, the lack of concepts and the difficulty of conforming the cases to the law.

Adolescent↗
PubMedDate not supplied

Distinction between carcinoma cells and mesothelial cells in serous effusions. Usefulness of immunohistochemistry.

The usefulness of an immunoperoxidase battery to distinguish carcinomatous from benign effusions was examined. Cell block sections from 90 previously diagnosed effusions were stained with antibodies to Leu-M1, B72.3, epithelial membrane antigen (EMA), carcinoembryonic antigen (CEA) and vimentin. The 90 cases comprised 69 carcinomas (23 mammary, 16 ovarian, 10 pulmonary, 7 gastrointestinal [GI] and 13 others), 2 malignant mesotheliomas and 19 cases with reactive mesothelial cells only. EMA and vimentin were the most useful markers for distinguishing carcinoma cells from reactive mesothelial cells. EMA reacted with 86% of the carcinomas while vimentin reacted with 90% of the reactive cases. Leu-M1, B72.3 and CEA, although generally less sensitive than EMA, were also helpful in this regard. Additionally, the use of Leu-M1 and CEA together may help to distinguish pulmonary from GI carcinomas.

Antibodies, Monoclonal↗