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Biomedical subjects

W R Cohen

Publications and source records attributed to W R Cohen.

At least 37 records · Page 2Linked to original sources
PubMed1989

Association of episiotomy and delivery position with deep perineal laceration during spontaneous delivery in nulliparous women.

Spontaneous deliveries of 241 nulliparous women were analyzed to test the hypothesis that both episiotomy and use of stirrups for delivery of infants were related to the occurrence of third- and fourth-degree perineal lacerations. These deep perineal tears occurred in 0.9% of the women delivered of infants without the use of either episiotomy or stirrups and in 27.9% of the women delivered of infants with both episiotomy and stirrups. Women exposed to episiotomy alone or to stirrups alone had intermediate rates of laceration. There was no independent correlation of laceration with maternal age, 1- and 5-minute Apgar scores, or midwife or physician as delivery attendant. The results suggest that selective use of episiotomy and stirrups can minimize perineal trauma during spontaneous delivery in nulliparous women.

Adult↗
PubMed1989

Heart rate patterns and fetal sepsis.

Fetal heart rate patterns from 15 cases of in utero bacterial fetal sepsis were reviewed. All patterns contained some abnormality, the most common being persistent tachycardia. Ninety-three percent of fetuses had periodic decelerations, which were either late or variable in nature. Neither maternal fever nor fetal tachycardia was invariably present during fetal infection. Although fetal sepsis was associated frequently with fetal heart rate pattern aberrations, no specific pattern was identified that was consistently or uniquely related to infection.

Adolescent↗
PubMed1988

Cardiac sympathetic activity during rat pregnancy.

The turnover of injected tracer [3H] norepinephrine (NE) was determined in heart and interscapular brown adipose tissue of virgin and 10-day and 20-day pregnant rats. In two experiments fractional [3H]NE turnover in heart was 87% and 92% higher in 20-day pregnant animals compared to virgin controls, but did not differ between 10-day pregnant and control animals. NE turnover in brown adipose tissue did not differ between control and pregnant animals at either gestational age. Twenty-four-hour urinary excretion of NE, epinephrine (E), and dopamine (D) was measured serially in six pregnant rats and compared to virgin controls. NE excretion during pregnancy was significantly higher than the controls and showed a progressive increase during the last third of pregnancy. At term the excretion rate was 2.6-fold greater than that of controls. Excretion of E and D did not differ between pregnant and nonpregnant animals. It is concluded that cardiac sympathetic nervous system activity increases during rat pregnancy. That this change in sympathetic activity is not global is indicated by the finding of unchanged NE turnover in interscapular brown adipose tissue. Urinary excretion data are consistent with increased sympathetic activity during late gestation, with no change in adrenal medullary function.

Adipose Tissue, Brown↗
PubMed1987

Disseminated herpes simplex infection in an immunocompromised pregnancy: treatment with intravenous acyclovir.

In this article, we report a case of third-trimester disseminated herpes simplex virus (HSV) infection in an immunocompromised gravida who was treated with parenteral acyclovir. Rapid resolution of lesions occurred, and the fetus was delivered at term without evident abnormalities. Of the four previous reports on this therapy, there has been one maternal death and survival of all neonates. Acyclovir should be considered in the treatment of disseminated HSV infection in pregnancy.

Acyclovir↗
PubMed1987

Plasma catecholamines in the hypoxaemic fetal rhesus monkey.

To assess the response of the sympathoadrenal system of the primate fetus to oxygen deprivation, we measured plasma catecholamines in 8 chronically catheterized fetal rhesus monkeys. A range of fetal hypoxaemia was produced by having the mother inspire 15, 10, or 9% oxygen mixtures while tranquilized with ketamine. Catecholamines from fetal carotid and maternal femoral arteries were measured by radioenzymatic assay. Fetal plasma norepinephrine and epinephrine concentrations increased significantly at all levels of hypoxaemia, but dopamine increased only at very low fetal oxygen tensions. Norepinephrine levels exceeded those of epinephrine and dopamine under all conditions. Relatively more severe hypoxaemia was necessary to elevate concentrations of epinephrine above baseline as compared with norepinephrine. A negative exponential correlation (P less than 0.001) was found between both fetal arterial PO2 and oxygen content and plasma norepinephrine and epinephrine, which was qualitatively similar to that observed previously in the sheep fetus. Maternal catecholamines were found to increase during hypoxaemia as well, but to a lesser degree than in the fetus.

Animals↗
PubMed1985

Fetal cardiovascular responses to asphyxia induced by decreased uterine perfusion.

Cardio-respiratory responses to asphyxia produced by decreased uterine perfusion were studied in 15 sheep fetuses. In chronic (spinal-anesthetized) and acute (inhalation-anesthetized) preparations, we measured fetal PO2, PCO2, pH, heart rate, arterial and umbilical venous pressures at rest and 5 min after controlled reductions of maternal aortic blood flow. Umbilical blood flow was determined by electromagnetic flow transducer on the fetal descending aorta with the iliac arteries ligated, in conjunction with radionuclide-labelled microspheres. In contrast to previous studies in which fetal hypoxaemia was produced by decreased maternally inspired O2 concentrations, decreasing degrees of uterine perfusion were associated with increasing degrees of hypercapnea and acidemia, as well as hypoxaemia. In chronic experiments, heart rate and umbilical blood flow fell significantly in response to decreased uterine perfusion with all degrees of hypoxaemia studied. In acute experiments, during the control period, PO2 values were similar to those of chronic experiments while values for pH and umbilical blood flow were lower and those for umbilical vascular resistance were higher. In the acute experiments, hypoxic stresses identical to those in the chronic studies failed to produce significant hemodynamic changes, except for bradycardia in response to severe hypoxaemia. These differences were apparently due to the pharmacologic effects of halothane and the operative stresses.

Anesthesia↗
PubMed1984

Adrenal secretion of catecholamines during hypoxemia in fetal lambs.

A new method for quantifying adrenal secretory function in chronically catheterized fetal lambs was developed. This preparation included insertion of a catheter distally into the fetal left renal vein and placement of a remotely operated, hydraulically controlled choker around the renal vein at its junction with the vena cava. With the choker open, adrenal venous blood flowed into the renal vein and then into the vena cava. With the choker closed, adrenal blood flowed into the catheter so that timed samples of adrenal venous effluent could be obtained. With this technique, left adrenal secretory rates of norepinephrine and epinephrine were determined across a spectrum of oxygen concentrations in five near-term fetal lambs. There was a rapid rise in norepinephrine secretion after induction of hypoxemia. Maximum secretory rates occurred at about 5 min, concomitantly with the lowest attained fetal arterial partial pressure of oxygen (PO2s). There was an inverse exponential relation between these catecholamine secretion rates and fetal arterial PO2 (P less than 0.001). Norepinephrine secretion appeared to increase in response to lesser degrees of hypoxemia than did epinephrine, although a longer time delay between stimulation and epinephrine response may have been a factor. Overall, norepinephrine secretion was greater than that of epinephrine. The ratios of norepinephrine to epinephrine in individual adrenal samples varied considerably and in some instances were less than one. These ratios did not correlate significantly with the degree of hypoxemia. During 25 min of a relatively steady state of hypoxemia, norepinephrine secretion declined markedly after about 5 min, although it remained above control levels throughout. Epinephrine secretion rose more gradually but then was relatively stable during the remaining period of hypoxemia.

Adrenal Glands↗
PubMed1983

Pulmonary edema associated with ritodrine and dexamethasone treatment of threatened premature labor. A case report.

Pulmonary edema occurred in association with the use of ritodrine and steroids to treat threatened premature labor. Twin gestation, intravenous ritodrine infusion longer than 24 hours and excessive fluid administration appear to be risk factors for the development of pulmonary edema. Careful case selection, scrupulous attention to the principles of fluid and electrolyte management and central venous pressure monitoring may help to diminish the incidence and severity of this complication of pregnancy.

Adult↗
PubMed1982

Plasma catecholamines during hypoxemia in fetal lamb.

Changes in peripheral plasma catecholamines were studied during varying degrees of hypoxemia in fetal lambs of 95-140 days gestation. Epinephrine and norepinephrine concentrations were measured by radioenzymatic assay in plasma obtained simultaneously from the distal aorta and inferior vena cava in 15 chronically catheterized fetuses with the mother breathing 20, 10, or 8% oxygen mixtures. Levels of both epinephrine and norepinephrine increased significantly after 5 min of hypoxemia and showed a strong inverse exponential correlation with PO2 (P less than 0.001). Plasma norepinephrine always exceeded epinephrine concentrations (P less than 0.01). Resting arterial and venous catecholamine levels were not different, but during hypoxemia arterial levels of both epinephrine and norepinephrine exceeded venous levels significantly, suggesting the adrenal medulla as a major source of these substances. Hypoxemia led to fetal bradycardia, the degree of which moderated somewhat with extremely low oxygen tensions and associated very high catecholamine levels. Fetal blood pressure increased initially in proportion to norepinephrine levels but reached a plateau at concentrations higher than 10 ng/ml. Although concentrations of catecholamines were lower in the earlier gestation fetuses studied, similar qualitative relations between catecholamines and PO2 were evident at all gestational ages.

Animals↗
PubMed1981

Cesarean section indication and the risk of respiratory distress syndrome.

The frequency of respiratory distress syndrome (RDS) was assessed according to indications for delivery and the presence of antecedent labor among 236 newborns delivered by cesarean section. The presence of labor preceding cesarean section did not reduce the risk of RDS significantly, although a trend, not statistically significant, was noted in this direction. Of the delivery indications evaluated, only abruptio placentae appeared to be associated with an increased risk of RDS. However, prematurity was shown to be a possible confounding variable in this regard. These data suggest that the risk of RDS associated with cesarean section is related to the mode of delivery per se and not necessarily to any of the associated factors evaluated in this study.

Birth Weight↗
PubMed1980

Risk of labor abnormalities with advancing maternal age.

The relationship between maternal age and the frequency of dysfunctional labor patterns was assessed retrospectively in a population of 6248 gravid women. A significant correlation between age and protraction disorders was observed in nulliparas. This could not be accounted for by patterns of anesthetic use, and it is speculated that a decrease in myometrial efficiency may accompany aging during the reproductive years.

Adult↗