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Biomedical subjects

J Cohen

Publications and source records attributed to J Cohen.

At least 1,207 records · Page 67Linked to original sources
PubMed1986

Longitudinal course of normal aging and progressive dementia of the Alzheimer's type: a prospective study of 106 subjects over a 3.6 year mean interval.

Elderly, community residing subjects (N = 106; mean age = 70.6 +/- 6.02 years) with cognitive functioning consistent with normal aging or dementia of the Alzheimer's type (DAT), were followed over a 3.6 year mean interval (range = 2.78 to 5.12 years). All subjects were assessed at baseline on the Global Deterioration Scale (GDS), a global clinical instrument reflecting the continuum of cognitive dysfunction from normal aging to severe DAT. At follow-up subjects were reassessed with respect to mortality, institutionalization and clinical change, defined as at least a two-point change on the 7-point GDS. Our results suggest that patients at deterioration levels GDS greater than or equal to 4, are more likely to show negative outcomes, specifically, institutionalization (Ps less than .001), death (Ps less than .01), or, for the community residing remainder, clinical deterioration (Ps less than .05), than subjects from less impaired (GDS = 2 or GDS = 3) subject groups. Seventy-six per cent of subjects at deterioration levels four or greater (N = 34) had negative outcomes at follow-up, whereas ninety percent of subjects with deterioration levels less than four (N = 72) did not.

Aged↗
PubMed1986

Steroid profiles during cycles with HCG stimulation of luteal function during in-vitro fertilization cycles.

178 in-vitro fertilization cycles have been explored for luteal function. Clomiphene and human menopausal gonadotrophins were used for ovarian stimulation and some patients were supplemented with human chorionic gonadotrophin (HCG) (5000 IU) on the day of laparoscopy, and also 2 and 4 days later. An imbalance of luteal function was observed in non-supplemented stimulated cycles, with hyperoestrogenicity and a relatively low production of progesterone. The administration of HCG reduced this imbalance by improving the production of progesterone without affecting the production of oestradiol-17 beta.

Adult↗
PubMed1986

Timing of in-vitro fertilization of cumulus-free and cumulus-enclosed human oocytes.

In humans, in contrast to other species, sperm capacitation requires a very short time, as in-vitro fertilization has been obtained after only 45 min of contact between oocytes and spermatozoa capacitated for 1 h. No fertilization occurred, whatever the duration of sperm capacitation, when gamete mixing did not exceed 30 min. On the contrary, 85% of cumulus-free mature oocytes exposed to sperm for 1-4 h were fertilized. The presence of the pre-ovulatory, fully-expanded or compact cumulus mass did not represent a physical barrier to sperm progression, as we observed no delay in fertilization when oocytes were enclosed in the cumulus. The use of a short insemination protocol (1-4 h instead of 17-20 h) did not reduce the fertilization rate of denuded or cumulus-enclosed oocytes and had no significant effect on the morphological appearance of the embryos or their cleavage rates.

Fertilization in Vitro↗
PubMed1986

In-vitro fertilization and embryo transfer: a collaborative study of 1163 pregnancies on the incidence and risk factors of ectopic pregnancies.

In a multi-centric study undertaken on 1163 pregnancies obtained by in-vitro fertilization, a 5% risk of ectopic pregnancies was observed. This figure is certainly higher than that admitted for natural reproduction. After simultaneous adjusting for all variables in our data by means of a multiple logistic regression technique, two factors have specific influence: the therapeutic use of clomiphene citrate which increased the rate of ectopic pregnancies from 3 to 6% and the number of patent Fallopian tubes with a change in ectopic pregnancies rate from 3 or 4% (with 0 or 2 patent tubes) to 13% (with one patent tube). These results suggest various physiologic hypotheses as well as therapeutic considerations.

Clomiphene↗
PubMed1986

Chromosome investigations in early life. I. Human oocytes recovered in an IVF programme.

Fifty-five oocytes recovered in an in-vitro fertilization (IVF) programme and remaining unfertilized when observed 42 h after insemination were prepared for chromosomal analysis. Sixteen oocytes displayed no polar body at the time of fixation and were supposed to be in metaphase I. In fact only two of them were in diakinesis, the others containing a diploid set of metaphase II chromosomes indicating that in 89% of the cases oocytes achieved meiosis without any extrusion of the first polar body. Thirty-nine oocytes in metaphase II were analysed. Nine were abnormal showing three D nullosomies, one G disomy, one double disomy for a 3 and a D chromosome, one deletion of the long arm of a G chromosome, one cell with extra chromosomes and/or chromosome breaks, one endoreduplication and one tetraploidy. The overall rate of abnormalities reached 22%. This high rate of chromosome anomalies can be explained by the nature of this population of fertilization failure, the frequently advanced maternal age and the use of superovulation treatments.

Chromosome Aberrations↗
PubMed1986

Infective complications of aplastic anaemia.

Patients with aplastic anaemia have a relatively specific immune defect--leucopenia with neutropenia. We have carried out a retrospective analysis of infective episodes in 11 patients with aplastic anaemia. 5723 follow-up days accrued and 29 infective episodes were documented. Overall the number of infective episodes was significantly associated with the mean white cell and monocyte counts (r = 0.59, 0.02 less than P less than 0.05) but not with length of follow-up, presentation values of white cell, neutrophil and monocyte counts, or mean neutrophil count. The patients appeared to divide clinically into two groups, those at low risk (seven patients) and those high risk (four patients) of infection. Patients in the high risk group had significantly more infections (P = 0.01) and significantly lower monocyte counts (0.02 less than P less than 0.05) than patients in the low risk group. These results are in contrast to similar studies in patients with chemotherapy-induced neutropenia; in our patients the overall rate and severity of infection was low, Gram negative infections were uncommon and monocytopenia appeared to be of greater importance than neutropenia in determining susceptibility to infection.

Adolescent↗
PubMed1986

Statistical approaches to suicidal risk factor analysis.

Suicide research is a particularly difficult area primarily because of the base rate problem and inadequate case finding. Traditional item-analytic and multiple regression or discriminant function data-analytic methods in suicide research are criticized on several technical grounds, including capitalization on chance, failure to cross-validate, and confusion of the degree of relationship with its statistical significance. These errors are further confounded when the research data base misrepresents the very low true base rate. However, the most serious defect in item-analytic and both conventional and stepwise multiple regression procedures is their failure to take into account the causal structure of suicide risk factors. Setwise hierarchical multiple regression/correlation analysis is offered as an effective tool for suicide research. It capitalizes on the powerful general data-analytic features of regression analysis, but does so in a way that represents the causal structure of the putative risk factors. The more complex methods of causal models analysis are also recommended. I do not believe, however, that progress in the understanding of suicide lies mainly in the improvement of the statistical procedures employed. Even with optimal procedures, the amount by which we can expect to increase the predictability of suicidality using psychosocial risk factors is not likely to be large. Recent research in the biochemistry of suicide offers some hope. If to the psychosocial factors now employed we can add relevant biological factors and their interactions with psychosocial factors, we may be able to develop the causal models necessary for the understanding, prediction, and prevention of suicide.

Depressive Disorder↗
PubMed1986

Ceftriaxone in the treatment of bacterial meningitis in children.

A total of 24 pediatric patients with a diagnosis of meningitis, confirmed by positive CFS culture, were enrolled in the study. All patients received ceftriaxone in different doses. No difference in clinical outcome was found between the patients who received ceftriaxone twice a day and the 11 who received the drug as a single daily dose. The latter dosage proves to be preferable. The therapeutic outcome in this series of patients was 22 cured and 2 failures. Bacteriological and pharmacokinetic findings are discussed.

Bacterial Infections↗
PubMed1986

Efficacy and safety of medium- and high-dose diltiazem alone and in combination with digoxin for control of heart rate at rest and during exercise in patients with chronic atrial fibrillation.

We evaluated the efficacy and the safety of medium-(240 mn/day) and high-dose (360 mg/day) diltiazem alone and in combination with digoxin when used for control of heart rate in 12 patients with chronic atrial fibrillation. Medium-dose diltiazem was comparable to therapeutic dose of digoxin at rest (88 +/- 19 vs 86 +/- 12 beats/min) but superior during peak exercise (154 +/- 23 vs 170 +/- 20 beats/min; p less than .05). High-dose diltiazem resulted in better control of heart rate than digoxin both at rest (79 +/- 17 beats/min; p less than .05) and exercise (136 +/- 25 beats/min; p less than .05) but was associated with side effects in 75% of the patients. Combined therapy of digoxin and diltiazem enhanced the effect of digoxin alone and resulted in significantly better control of heart rate at rest (67 +/- beats/min with medium-dose and 65 +/- beats/min with high-dose diltiazem) and during peak exercise (132 +/- 32 and 121 +/- 24 beats/min, respectively). However, the difference in heart rate between these two doses was not significant. Reduction of heart rate combined with concomitant effect on blood pressure resulted in a significant fall in pressure-rate product at rest from 10,077 +/- 1708 mm Hg/min on digoxin alone to 7877 +/- 1818 mm Hg/min after the addition of medium-dose diltiazem (p less than .05) and during exercise form 25,670 +/- 3606 to 18,439 +/- 4115 mm Hg/min (p less than .05). Continued therapy with digoxin combined with diltiazem 240 mg/day for 21 +/- 8 days in nine patients showed persistent effect on heart rate and blood pressure without any toxic manifestations or change in serum digoxin (1.5 +/- 0.4 vs 1.3 +/- 0.4 ng/ml) or plasma diltiazem concentrations (204 +/- 72 vs 232 +/- 129 ng/ml). In conclusion, medium-dose diltiazem when combined with digoxin is an effective and safe regimen for the treatment of patients with chronic atrial fibrillation and enhances digoxin-mediated control of heart rate both at rest and during exercise.

Adult↗
PubMed1986

A better method for terminal bleeding of mice.

A new method for exsanguinating mice is described. The procedure is carried out under CO2-anaesthesia and involves venepuncture of the caudal (inferior) vena cava and gentle aspiration of blood into a syringe. It consistently gives large volumes of blood (1.60-2.50 ml/mouse), free from haemolysis and contamination. The technique is easy, quick and reliable.

Animals↗
PubMed1986

Fate of superfluous sperm products after vasectomy and in the normal male tract of the mouse.

The progression of 3H-labelled spermatozoa (thymidine or arginine) was followed through the tracts of unilaterally vasectomized, bilaterally vasectomized, oligozoospermic (t6/tw5) and normal mice; the regional lymph nodes were also investigated. The same rate of sperm production and transport was found in normal and in vasectomized tracts, down to the corpus epididymidis; there was some delay in spermatozoa entering the cauda in the vasectomized tracts. In the mouse, therefore, vasectomy does not affect the rates of sperm production or transport until just before the blockage in the swollen cauda epididymidis. Radioactivity appeared in the caudal and 'para-aortic' lymph nodes as the radioactive spermatozoa passed from the corpus, showing that this is one route of disposal of spermatozoa, or of sperm products, after vasectomy. Naturally oligozoospermic and normal mice gave similar results; again the caudal, iliac and renal lymph nodes received radioactive spermatozoa/sperm products. Some loss of (by definition) superfluous spermatozoa in the normal male tract therefore occurs naturally by this route, and we suggest that vasectomy further exploits this physiological pathway. This would account for the finding that many males do not make antisperm antibodies after vasectomy, just as normal males do not, even though their lymph nodes normally receive spermatozoa/sperm products.

Animals↗
PubMed1986

Increased monoester lipase activity in red blood cells during hyperthyroidism.

Human red blood cells (RBC) contain a monoester lipase (MEL) activity which is tightly associated with the cell membrane and has its active site externally oriented, as inferred from the ability of the intact cell to hydrolyse an exogenously added lipid substrate. Membrane-bound MEL activity was measured by a radiochemical assay in intact RBC from 29 untreated hyperthyroid patients. The mean (+/- S.D.) MEL level was higher (P less than 0.01) in these patients (1220 +/- 212 mu./10(12) RBC) than in the control group (1010 +/- 120 mu./10(12) RBC). There was no difference between men and women. The increase in MEL values was associated with significantly (P less than 0.001) decreased values of mean cellular volume and mean cellular haemoglobin content. A continued study of 13 patients, who became euthyroid with treatment, showed a normalization of the MEL values in RBC. The increased lipolytic potency of RBC represents a new characteristic of hyperthyroid patients. Further exploration of the possible diagnostic or prognostic implications of this enzymatic change seems warranted.

Adolescent↗
PubMed1986

Life expectancy of kibbutz members.

Data are presented demonstrating that the life expectancy (LE) of kibbutz members--both men and women--is higher than that of the overall Jewish population in Israel. Closer inspection of the death rates at various ages reveals that, from age thirty, those of kibbutz women are lower than those of the Jewish population. Although those of kibbutz men are actually higher until age forty-nine, nevertheless the LE of kibbutz members (based on death rates) surpasses that of Jews in Israel. These data add to and support other research findings illustrating the more positive mental health and well-being found among kibbutz members than among other comparative populations. Similarly, the factors contributing to kibbutz members' life expectancy evolve from this quality of life, especially as this quality of life affects old age.

Culture↗