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Biomedical subjects

S L Clark

Publications and source records attributed to S L Clark.

At least 55 records · Page 3Linked to original sources
PubMed1992

The effect of porcine somatotropin supplementation in pigs on the lipid profile of subcutaneous and intermuscular adipose tissue and longissimus muscle.

The effect of porcine somatotropin (pST) on the lipid profiles of adipose tissue and muscle was investigated. Sixteen crossbred barrows were injected daily with either 3 mg of pST or a placebo. After slaughter, total lipid and fatty acid composition of raw subcutaneous (SC) adipose and intermuscular (IM) adipose tissue and longissimus muscle were determined. The SC adipose tissue from pST-treated pigs had a 7.5% decrease in total lipid content; specific fatty acids 16:0, 18:0, and 18:1(n-9)c decreased most. The IM fat from pST-treated pigs had lower levels of 16:0 and 20:0. There was no effect of pST treatment on the lipid profile of the longissimus muscle. The data suggest that pST treatment produces small but significant changes in the saturated fatty acid content of adipose tissue in pigs.

Adipose Tissue↗
PubMed1992

Maternal respiration and blood gases during aerobic exercise performed at moderate altitude.

We studied whether maternal acid-base status during aerobic exercise performed at moderate altitude is affected by pregnancy. Seven primiparus women were tested at 37 wk gestation and 12 wk postpartum. Subjects were studied at rest, and during two cycle (50 W, 75 W) and two treadmill (67 m.min-1; 2.5% grade, 67 m.min-1; 12% grade) protocols. Exercise bouts lasted 6 min with a 10-min rest between sessions. Minute (VE) and alveolar (VA) ventilation, tidal volume (VT), and ventilatory equivalent for carbon dioxide (VE/VCO2) were significantly (P less than 0.01) greater when exercise was performed during pregnancy. Physiological dead space (VD) was not affected by pregnancy status and did not differ between rest and exercise. Decreases (P less than 0.01) in arterial pH during exercise averaged 0.04 units in both pregnancy and postpartum. Despite similar change in maternal pH, carbon dioxide tension (PaCO2) remained unchanged during exercise at 37 wk gestation but decreased at 12 wk postpartum. Decreases in arterial bicarbonate [HCO3-] associated with exercise were smaller during pregnancy. Our findings indicate that pregnancy did not compromise maternal acid-base status during aerobic exercise.

Acid-Base Equilibrium↗
PubMed1992

Premature rupture of the membranes: management controversies.

Preterm premature rupture of the membranes continues to be a leading cause of perinatal morbidity and mortality in the United States. In the absence of amnionitis or fetal compromise, expectant management is a reasonable alternative to permit fetal weight gain and to allow for fetal lung maturation. When embarking on an expectant management course, a variety of clinical approaches are available to the practicing clinician.

Adrenal Cortex Hormones↗
PubMed1991

Position change and central hemodynamic profile during normal third-trimester pregnancy and post partum.

Central hemodynamic response to position change was assessed in 10 normotensive primiparous patients between 36 and 38 weeks' gestation. Studies were repeated between 11 and 13 weeks post partum. Compared with the left lateral position, we observed a mean 9% fall in cardiac output in the supine position and an 18% fall when patients were standing. When standing, these patients had a 30% increase in pulse and a 21% fall in left ventricular stroke work index. The orthostatic response after pregnancy was much more labile than that during the third trimester. These findings have important descriptive implications for the understanding of the human response to orthostasis during pregnancy, as well as clinical implications for patients at risk of uteroplacental insufficiency and for working women during pregnancy.

Adult↗
PubMed1991

Cardiac disease in pregnancy.

The pregnant patient with normal cardiac function can accommodate many significant alterations in the cardiovascular system without difficulty. Pregnancy in a patient with significant cardiac disease, however, can be extremely hazardous, resulting in decompensation and even death. these conditions account for up to 30% of maternal mortality. This article reviews the interaction between cardiac disease and pregnancy.

Cardiomyopathies↗
PubMed1991

Amniotic fluid embolism.

Amniotic fluid embolism remains an enigmatic and often lethal condition. The pathophysiology is complex, however, from a clinical standpoint. Right or, more commonly, left heart failure is the dominant physiologic aberration. Disseminated intravascular coagulation is often present. The detection of squamous cells in the central circulation of living patients can no longer be considered pathognomonic for this condition.

Embolism, Amniotic Fluid↗
PubMed1991

Recent developments in pregnancy-induced hypertension.

Pregnancy-induced hypertension (PIH) still remains an area in obstetrics of active research and investigation. Despite widespread academic attention, the cause of this disorder still remains unknown. The purpose of this paper is to review the important contributions to the literature during the period of July, 1990 through June, 1991. Elucidation of the pathophysiology of PIH has been enhanced by investigations of altered platelet calcium metabolism, the renin-aldosterone-angiotensin system, and other potent vasopressors. Recent reports of clinical management for eclampsia, liver rupture, HELLP syndrome, severe PIH in the second trimester, severe hypertension, and magnesium toxicity are presented.

Anticonvulsants↗
PubMed1991

Cardiac disease in pregnancy.

Cardiac disease in pregnancy remains a major cause of indirect maternal death. An understanding of the impact of the physiologic changes associated with pregnancy upon structural cardiac disease is essential for proper counseling and management of these complex patients.

Counseling↗
PubMed1990

Cardiac output responses of primigravid women during exercise determined by the direct Fick technique.

We compared metabolic and cardiovascular responses to aerobic exercise with the direct Fick technique in women during and after pregnancy. Seven subjects were studied at 37 weeks' gestation and again 12 weeks postpartum. All were tested at rest and during four sequential exercise bouts consisting of 5 minutes at each of two cycle (50 and 75 W) and two treadmill (67 m x min-1 at 2.5 and 12% grade) protocols. Oxygen consumption (VO2) and heart rate were measured during the fifth minute of exercise. Arterial and mixed venous oxygen contents, obtained from catheters placed in the radial and pulmonary arteries, respectively, were used to calculate arterial-venous oxygen difference. Cardiac output and stroke volume were calculated from the Fick equation. Responses of VO2, cardiac output, and stroke volume were greater when exercise was performed at 37 weeks' gestation as compared with postpartum. In contrast, heart rate response (during cycling) and arterial-venous oxygen difference (during treadmill walking) were less when exercise was performed during pregnancy. Our results indicate that there is no compromise in maternal cardiac output during either cycle or treadmill exercise performed late in pregnancy as compared with postpartum conditions.

Adult↗
PubMed1989

Fetal heart rate transmission with the facsimile telecopier in rural areas.

Over a 30-month period, 24 portable facsimile telecopiers were placed in rural hospitals with delivery services, allowing 24-hour direct transmission of fetal heart rate tracings for consultation. An analysis of the first 209 intrapartum fetal heart rate strips is presented. Variable decelerations were the most frequent indication for consultation, but they were less commonly interpreted as indicating fetal distress. Such units have major advantages in terms of both cost and versatility over previously described systems and have proved extremely valuable to the rural practitioner of obstetrics.

Electrocardiography↗
PubMed1989

Central hemodynamic assessment of normal term pregnancy.

Ten carefully screened primiparous patients between 36 and 38 weeks' gestation underwent pulmonary artery catheterization, arterial line placement, and central hemodynamic assessment in the left lateral recumbent position. Studies were repeated in the same patients between 11 and 13 weeks post partum. Compared with the nonpregnant state, there was a significant fall in systemic vascular resistance, pulmonary vascular resistance, colloid oncotic pressure, and colloid oncotic pressure-pulmonary capillary wedge pressure gradient by the late phase of the third trimester (p less than 0.05). Pregnancy was associated with a significant rise in cardiac output and pulse in all patients (p less than 0.05). There was no significant change in pulmonary capillary wedge pressure, central venous pressure, left ventricular stroke work index, or mean arterial pressure. Normally the late phase of the third trimester is not associated with hyperdynamic left ventricular function as assessed by the left ventricular stroke work index/pulmonary capillary wedge pressure ratio.

Adult↗
PubMed1989

Nonstress testing with acoustic stimulation and amniotic fluid volume assessment: 5973 tests without unexpected fetal death.

In a 36-month period antepartum testing was performed 5973 times in 2628 women with singleton high-risk pregnancies. The testing scheme involved a modified nonstress test with sound stimulation. Testing was performed twice weekly for patients with diabetes (classes B through R), gestational age exceeding 42 weeks, and documented intrauterine growth retardation, and weekly for other indications. If no spontaneous acceleration was observed within 5 minutes, a single 1- to 2-second sound stimulus was applied to the lower maternal abdomen with an artificial larynx. If necessary, a second sound stimulation was applied within 10 minutes. In addition all patients received ultrasonographic four-quadrant assessment of amniotic fluid volume. The mean testing time was 10 minutes. Only 2% of tests were nonreactive with sound stimulation. Seventeen percent of nonstress tests that were nonreactive with sound stimulation were followed by positive results of a contraction stress test or a biophysical profile score less than or equal to 4. The overall intervention rate was 3%. All fetuses with a single acceleration only eventually met criteria for negative results to a contraction stress test or had a biophysical profile score greater than or equal to 8. There were no unexpected antepartum fetal deaths. Sound-induced accelerations appear to be valid in the prediction of fetal well being, and the use of sound stimulation results in a significant shortening of testing time. Simultaneous assessment of amniotic fluid volume may reduce the risk of fetal death to a negligible level.

Acoustic Stimulation↗