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Biomedical subjects

E Cohen

Publications and source records attributed to E Cohen.

At least 19 recordsLinked to original sources
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↗
PubMed1991

Corneal ulcer and adverse reaction rates in premarket contact lens studies.

We analyzed clinical data on 22,739 contact lens wearers who were studied and whose lenses were approved under 48 manufacturer-sponsored studies for the Food and Drug Administration between 1980 and 1988. The incidence of corneal ulcers was low in the cosmetic (nontherapeutic) daily-wear soft and rigid gas-permeable lens wearers (1/1,923 and 1/1,471 patient-years, respectively). Corneal ulcers and severe adverse reactions occurred two to four times more frequently in extended-wear cosmetic soft and rigid gas-permeable lens wearers than in cosmetic daily-wear lens wearers. Aphakic extended-wear soft lens users were nine times more likely to develop a corneal ulcer when compared to the soft daily-wear cosmetic group. Corneal abrasions and keratitis accounted for 81 of 159 severe adverse reactions, whereas corneal ulcers accounted for 28 of 159 adverse reactions. The data indicate that overnight extended wear of contact lenses is associated with a greater risk of serious, sight-threatening complications than daily wear.

Aphakia↗
PubMed1991

Postgastrostomy tube deformity on upper GI series.

Three cases are presented in which a focal concave deformity occurred along the greater curvature of the stomach on upper gastrointestinal (GI) series. These patients all had recent removal of a surgically placed gastrostomy tube from a similar location. This deformity appears to be related, at least in part, to invaginated gastric mucosa intentionally produced during surgical gastrostomy tube placement. This association and appearance should be noted as it may mimic other lesions.

Adult↗
PubMed1991

Peri-cholecystic hyper-echogenicities in necrotizing enterocolitis: a specific sonographic sign?

The authors report a new sonographic pattern found in association with neonatal necrotizing enterocolitis in 5 newborns: hyperechogenicities around the gallbladder. The pattern probably corresponds to extension of the disease to the perivesicular space. The most probable hypothesis for that extension is diffusion by contiguity through the lesser sac and/or the right gutter. The hyperechogenicities could be related to the foamy infiltrate typical of NEC. Air within the pericholecystic vascular system similar to portal air could be another (less probable) explanation.

Enterocolitis, Pseudomembranous↗
PubMed1991

Photoprotection of Bacillus thuringiensis kurstaki from ultraviolet irradiation.

Irradiation of Bacillus thuringiensis var. kurstaki HD1 at 300-350 nm for up to 12 hr using a photochemical reactor results in a rapid loss of its toxicity to larvae of Heliothis armigera. Photoprotection of the toxic component was obtained by adsorption of cationic chromophores such as acriflavin (AF), methyl green, and rhodamine B to B. thuringiensis. AF gave the best photoprotection and a level of 0.42 mmol/g dye absorbed per gram of B. thuringiensis was highly toxic even after 12 hr of ultraviolet (uv) irradiation as compared to the control (77.5 and 5% of insect mortality, respectively). Ultraviolet and Fourier-transform infrared spectroscopic studies indicate molecular interactions between B. thuringiensis and AF. The nature of these interactions and energy or charge transfer as possible mechanisms of photoprotection are discussed. It is speculated that tryptophan residues are essential for the toxic effect of B. thuringiensis. It is suggested that photoprotection is attained as energy is transferred from the excited tryptophan moieties to the chromophore molecules.

Bacillus thuringiensis↗
PubMed1991

HEADSS, a psychosocial risk assessment instrument: implications for designing effective intervention programs for runaway youth.

In this article, we present data obtained with the psychosocial interview instrument, HEADSS (Home, Education, Activities, Drug use and abuse, Sexual behavior, Suicidality and depression) that was administered to High Risk Youth Clinic clients at their initial visits during a 1-year period. Of the 1,015 new patients, 63% were homeless/runaway youths and 37% were living with their families. Utilizing the HEADSS interview instrument, we compared homeless/runaway youths to nonhomeless youths in a number of areas, including risks for human immunodeficiency virus (HIV) infection. Our results showed that homeless teens tended to be younger, female, and white compared to their nonhomeless counterparts. They were more likely to have dropped out of school and were far more likely to be depressed and actively suicidal. They demonstrated all forms of drug abuse. They engaged in first sexual intercourse at an earlier age, and experienced a higher incidence of sexual abuse and prostitution. They were 6 times more likely to be at risk for HIV infection.

Adolescent↗
PubMed1991

Microcircuitry related to the receptive field center of the on-beta ganglion cell.

1. We have investigated the anatomic basis for the Gaussian-like receptive field center of the on-beta ("X") ganglion cell in the area centralis of cat retina. Three adjacent on-beta cells were reconstructed from electron micrographs of 279 serial sections cut vertically through a patch of retina at approximately 1 degree eccentricity. 2. All the bipolar synapses on these cells were identified, and about one-half of these were traced to type b1 bipolar cells, which formed a regular array in the plane of the retina. 3. On average, seven b1 cells contributed to a beta cell: bipolar axons near the middle of the beta dendritic field tended to give many contacts (12-33 contacts); axons near the edge of the field tended to give few contacts (3-4 contacts). 4. Each b1 cell collected from four to seven cones, and the mean number of cones converging through the b1 array to a beta cell was 30. 5. Assuming equal effectiveness for all b1----beta cell synapses, a spatial weighting function was derived from these results. The mean radius of this function at 1/e amplitude for three beta cells was 18.0 +/- 1.1 (SD) microns. This is considerably narrower than the corresponding measurements of the beta cell receptive field center (28 +/- 3 microns) at this eccentricity. 6. It is concluded, in agreement with previous work, that all cones encompassed by the beta cell's dendritic field and those slightly beyond it connect directly to the beta cell via the b1 bipolar cell array. However, the center of the beta cell receptive field is still broader by approximately 60%. This suggests that pooling of cone signals may occur at the level of the outer plexiform layer.

Animals↗
PubMed1991

Seborrheic skin and acne vulgaris as protective factors against the development of basal cell epithelioma.

This study was conducted in order to evaluate a possible protective role of seborrheic complexion and a history of acne on the development of basal cell epithelioma (BCE). For this purpose, 77 patients with this tumor were examined and asked to fill out a questionnaire. The questionnaire included demographic data and questions about skin type, eye and hair colors, sun exposure habits and a past history of acne. The nature, number and location of tumors, the texture of skin and acne scars were noted by a physician. A group of 93 age-, sex- and skin-color-matched patients served as controls. The results show a clear relationship between seborrheic features and a lower risk of developing BCE, after controlling for solar exposure using the Mantel-Haenszel summary measure. The same trend was found in patients with a history of acne. Whether ultraviolet light absorption by sebum, an anticancer activity of Propionibacterium acnes or other factors play a protective role against the development of BCE is as yet unclear.

Acne Vulgaris↗
PubMed1991

Effect of cyclosporine A on the hearing loss in Behçet's disease.

Thirty-five patients with Behçet's disease (20 under cyclosporine A [CyA] treatment and 15 under the conventional therapy), 12 patients suffering from endogenous uveitis, and 35 normal subjects were evaluated audiologically before entering the study and were followed up for at least a year. Twenty-eight Behçet patients (80%) showed some degree of hearing loss. The averaged pure tone audiogram of the Behçet group showed statistically significant auditory deficits in comparison with that of the control group. None of either the Behçet group or the uveitis group showed any hearing deterioration during the follow-up period. Five Behçet patients under CyA therapy demonstrated improvement in their hearing. The difference between the two groups of Behçet patients (CyA versus conventional treatment) was found to be statistically significant (p less than .05). Thus, CyA might serve as an important mode of treatment of sensorineural hearing loss on an inflammatory "autoimmune" background.

Acoustic Impedance Tests↗
PubMed1991

The effect of in vitro irradiation on human NK cell activity. A preliminary report.

Natural killer activity of peripheral blood cells was evaluated after in vitro irradiation at doses ranging between 100 and 1600 cGy. Natural killer (NK) cells from normal donors exhibited a trend towards increased cytotoxicity peaking at about 600 cGy and then gradually decreasing. NK cells isolated from peripheral blood of cancer patients showed a lower baseline of activity, which was less affected by the same doses of in vitro irradiation. A distinction could be made between patients with early disease and those with advanced cancers; patients with early cancers showing NK activity close to that of normal donors.

Acute Disease↗