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Biomedical subjects

E Cohen

Publications and source records attributed to E Cohen.

At least 181 records · Page 10Linked to original sources
PubMed1993

Identification of tRNAs incorporated into wild-type and mutant human immunodeficiency virus type 1.

We have identified the tRNAs which are incorporated into both wild-type human immunodeficiency virus type 1 strain IIIB (HIV-1IIIB) produced in COS-7 cells transfected with HIV-1 proviral DNA and mutant, noninfectious HIV-1Lai particles produced in a genetically engineered Vero cell line. The mutant proviral DNA contains nucleotides 678 to 8944; i.e., both long terminal repeats and the primer binding site are absent. As analyzed by two-dimensional polyacrylamide gel electrophoresis, both mutant and wild-type HIV-1 contain four major-abundance tRNA species, which include tRNA(1,2Lys), tRNA(3Lys) (the putative primer for HIV-1 reverse transcriptase) and tRNA(Ile). Identification was accomplished by comparing the electrophoretic mobilities and RNase T1 digests with those of tRNA(3Lys) and tRNA(1,2Lys) purified from human placenta and comparing the partial nucleotide sequence at the 3' end of each viral tRNA species with published tRNA sequences. Thus, the absence of the primer binding site in the mutant virus does not affect tRNA(Lys) incorporation into HIV-1. However, only the wild-type virus contains tRNA(3Lys) tightly associated with the viral RNA genome. The identification of the tightly associated tRNA as tRNA(3Lys) is based upon an electrophoretic mobility identical to that of tRNA(3Lys) and the ability of this RNA to hybridize with a tRNA(3Lys)-specific DNA probe. In addition to the four wild-type tRNA species, the mutant HIV-1-like particle contains two tRNA(His) species and three tRNA-sized species that we have been unable to identify. Their absence in wild-type virus makes it unlikely that they are required for viral infectivity.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Recurrent transient bone marrow hypoplasia associated with pregnancy.

A 24-year-old female was admitted for evaluation of thrombocytopenia during her second pregnancy. During the second trimester of her first pregnancy, the patient developed aplastic anemia which resolved completely following termination of pregnancy. Three and a half years later she was admitted in the third trimester of pregnancy suffering from severe thrombocytopenia and hypoplastic bone marrow which improved after a normal delivery. To the best of our knowledge this is the first description of recurrent bone marrow hypoplasia associated with pregnancy.

Adult↗
PubMed1993

Preparing for terror.

Terrorists enjoy their exposure in the international press. Their acts and treats of violence are heralded in headlines and broadcast throughout the world. They purposely inflict damage in public places where there are large numbers of victims, with the potential for a great deal of destruction and debris. They intend to inflict economic loss, instill fear and disrupt everyday life, while at the same time believing their need to maim and kill is justified. Is it no wonder that the World Trade Center was a highly prized target? You must remember that terrorism involves the perpetrator's willful, calculated choice to use innocent victims as targets, and that the terrorist's acts are deliberate, systematic murders to inspire fear for political or criminal ends. As Brian Jenkins stated back in 1983, "terrorism is never a short-term event...you never really get over it...and its effects can't be buried or forgotten." Thus, our responsibility, as EMS providers, is to recognize the threat and refuse to be lulled into a sense of complacency. The United States is at risk, and our greatest threat may even come from our own ranks: political crusaders, activists, hate groups, drug merchants and gangs. The criminals, zealots, fanatics and extremists of the world will continue to believe their crusades and turf battles can be won through terrorist acts. It's up to us to respond effectively to the aftermath.

Disaster Planning↗
PubMed1993

Who will practise emergency medicine? Survey of family medicine graduates.

A survey of recent family medicine graduates showed that two thirds were doing no emergency work. Those who had originally planned to practise emergency medicine were more likely to be doing it than those who had not. More women than men dropped their plans to do emergency work. Two thirds of those who had dropped their plans thought their training had influenced the decision.

Attitude of Health Personnel↗
PubMed1992

Variable tRNA content in HIV-1IIIB.

Low molecular weight RNA in HIV-1 is found in three size classes resembling 7S RNA, 5S RNA, and tRNA. The 2-dimensional polyacrylamide gel electrophoresis (2D PAGE) patterns of tRNA found in HIV-1 have been determined in virus produced in five different cell types: H9, UHC1 (a U937-derived clone), UHC8 (an RT(-) derivative of U937), HeLa, and COS. The presence of the putative primer tRNA for reverse transcriptase, tRNA(Lys,3), has also been determined either by hybridization with a tRNA(Lys,3)-specific DNA probe or by a comparison of the electrophoretic mobility of viral tRNA species with purified human tRNA(Lys,3). Our results indicate the following: 1) The number of tRNA species found in infectious HIV-1IIIB produced in different cell types varies, according to cell type, from greater than 20 to 4, indicating that only 4 or less tRNA species are required for the viral infectious life cycle. 2) There are 1-3 tRNA species tightly associated to the viral genomic RNA, depending upon the cell type producing the virus. 3) The putative primer tRNA, tRNA(Lys,3), is detected with the tRNA(Lys,3)-specific hybridization probe in the tRNA of HIV-1 produced in H9 cells, and the tightly associated tRNA species in this virus has the same electrophoretic mobility in 1-D PAGE as purified tRNA(Lys,3). On the other hand, we cannot detect tRNA(Lys,3) in the tRNA of HIV-1 produced in HeLa cells, and the tightly associated tRNA found in this virus does not migrate with the same electrophoretic mobility as tRNA(Lys,3).

Animals↗
PubMed1992

Balloon expulsion test facilitates diagnosis of pelvic floor outlet obstruction due to nonrelaxing puborectalis muscle.

We compared balloon expulsion, defecography, colonic transit times, anal manometry, and electromyography in 21 patients with severe constipation. Defecography demonstrated nonrelaxation of the sphincter during straining in all patients. Only 12 patients were unable to expel a balloon. Colonic transit was normal (five) or showed rectosigmoid delay (seven). All 12 patients were offered biofeedback. The nine patients able to expel a balloon had normal colonic transit (six) or colonic inertia (two). Rectosigmoid delay was due to severe intussusception in one patient. Anal manometry and pudendal nerve latencies revealed no difference between those who could and those who could not expel a balloon. Balloon expulsion seems to be a more reliable way to diagnose pelvic floor outlet obstruction due to nonrelaxation of the puborectalis muscle. Nonrelaxation of the sphincter on defecography should be correlated with balloon expulsion and colonic transit studies.

Adult↗
PubMed1992

Comparison of mu opioid receptors in brains of rats bred for high or low rate of self-stimulation.

Opiates and endogenous opioid peptides play an important role in reward-mediated behaviors, including self-stimulation. Two strains of rats, LC2-Hi and LC2-Lo, selectively bred for high vs. low rate of lateral hypothalamic self-stimulation, were employed in the present study. Quantitative autoradiography was performed on brains of adult male rats of each strain, using the mu opioid receptor agonist 3H-DAGO. Strain differences in receptor density were observed in the nucleus accumbens and in ventral areas of the hippocampus.

Animals↗
PubMed1991

Hypertension in women: what is really known? The Women's Caucus, Working Group on Women's Health of the Society of General Internal Medicine.

PURPOSE: To determine whether there is sufficient information in the medical literature to guide appropriate treatment of hypertensive women. DATA IDENTIFICATION: Epidemiologic surveys of hypertension, clinical trials of antihypertensive therapy, and studies of selected adverse effects of antihypertensive agents were identified through a computerized search using MEDLINE and by identifying all studies cited in current medical textbooks as supporting evidence for the guidelines for the treatment of hypertensive individuals. All epidemiologic studies selected were cross-sectional or longitudinal, multicenter, population-based surveys. All clinical trials were large, randomized studies comparing one or more antihypertensive agents with a placebo or nonplacebo control group. Epidemiologic studies and clinical trials were reviewed to assess the quantity and quality of information available regarding important aspects of hypertension in women. Data pertaining to epidemiology, natural history, results of treatment, and two significant side effects of antihypertensive treatment were examined. RESULTS OF DATA ANALYSIS: The prevalence of hypertension is greater in black women than in black men and is about equal in white women and men. Because women outnumber men in the population, there are more hypertensive women than men. The attributable risk percent (the proportion of end points that could be eliminated by removing hypertension) for cardiovascular complications of hypertension is higher for women than men. Clinical trials show clear benefit of therapy for black women but no clear benefit for white women; some studies suggest that treatment of white women is harmful. Lipid profiles and their relation to ischemic heart disease differ for women and men; there is currently no information on the effects of antihypertensive agents on serum lipids in women. Few data have been published on the frequency of sexual dysfunction in treated hypertensive women. CONCLUSIONS: Hypertension in women and its related cardiovascular outcomes are a major public health problem. Clinical trials of antihypertensive therapy do not fully support current guidelines for the treatment of hypertensive women. Research concerning adverse effects of antihypertensive agents has largely excluded women from consideration; further studies are required to guide appropriate treatment.

Black or African American↗