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Biomedical subjects

M Katz

Publications and source records attributed to M Katz.

At least 469 records · Page 26Linked to original sources
PubMed1980

Sinusoidal fetal heart rate. I. Clinical significance.

Sixteen cases of SHR are analyzed with respect to perinatal outcome, fetal scalp and umbilical arterial pH, and characteristics of the FHR pattern. There were no perinatal deaths in this series. The SHR is defined and a plan for management of the patient with SHR is proposed. A theoretical explanation of the pathophysiology of SHR is presented in terms of a fetal compensatory mechanism for hypoxia, based on these observations as well as a review of the literature. Biochemical data may provide valuable information permitting optimal management of patients with SHR patterns.

Adolescent↗
PubMed1980

Sinusoidal fetal heart rate. II. Continuous tissue pH studies.

Two cases of SHR in labor monitored by continuous fetal tissue pH measurements are presented. Both showed onset of the pattern in the absence of fetal acidosis, a fall in TpH following the appearance of the abnormal FHR pattern, and fetal compensation with a good perinatal outcome. These patients demonstrate that the fetus may tolerate a SHR and recover from preacidosis and acidosis. Continuous pH measurement may be helpful in conservative management of patients with abnormal FHR patterns.

Acid-Base Equilibrium↗
PubMed1980

Uterine and renal renin release after ligation of the uterine arteries in the pregnant rabbit.

Uteroplacental ischemia is associated with uterine renin release in pregnant nephrectomized rabbits. In the present study, uterine and renal renin release after uteroplacental ischemia were investigated in 10 Australian white rabbits at 24 to 28 days' gestation. Pentobarbital was administered, and both uterine arteries were ligated close to their origins. Blood samples were taken for plasma renin activity (PRA) determinations from the femoral artery, uterine vein, and right renal vein before ligation and at 30 and 60 minutes after ligation. Mean arterial blood pressure (MAP) was monitored throughout. In five additional pregnant rabbits renal blood flow (RBF) was measured with an electromagnetic flowmeter. The preligation uterine vein-artery PRA difference was not significant (1.9 +/- 1.1 ng/ml/hr). Postligation uterine vein-artery PRA was 11.4 +/- 3.2 at 30 minutes and 6.6 +/- 1.9 ng/ml/hr at 90 minutes (p less than 0.02). Preligation renal vein-artery PRA was 32.3 +/- 10.5 ng/ml/hr (p less than 0.02) and did not change significantly after ligation. MAP remained stable and RBF was unchanged after uterine artery ligation. These observations confirm the finding that the kidney is the primary source of renin in the normal pregnant rabbit and demonstrate that following acute uteroplacental ischemia there is significant uterine renin release even when the kidneys are intact.

Animals↗
PubMed1980

Sparing of the brain in neonatal undernutrition: amino acid transport and incorporation into brain and muscle.

Rates of tyrosine and lysine transport and incorporation into protein were measured in control and undernourished weanling rats. Undernutrition was induced by feeding lactating dams a low protein diet (12 percent casein) from birth to day 21. At weaning, body and brain weights of undernourished rats were 50 percent and 88 percent, respectively, of control values. Lysine and tyrosine transport rates into skeletal muscle were reduced by over 75 percent, more than twice the reduction seen in brain. Rates of amino acid incorporation into muscle protein were reduced by approximately 50 percent; the change in rate of incorporation into brain protein was not statistically significant. These data indicate that, in spite of marked retardation of amino acid transport into brain, the brain seems fully capable of maintaining normal rates of protein synthesis.

Amino Acids↗
PubMed1980

Neonatal heart rate reactivity following variable decelerations during labor.

The instantaneous heart rate of 65 healthy neonates was continuously monitored during labor and the first 30 minutes of neonatal life. It was found that infants who had moderate or severe variable decelerations in utero had a significantly delayed neonatal heart rate (NHR) reactivity without any evidence of perinatal asphyxia. The NHR pattern of infants with and without variable decelerations is described and possible mechanisms which could explain the delayed NHR reactivity are discussed.

Adult↗
PubMed1980

Circumcision.

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Circumcision, Male↗
PubMed1980

A gonadotropin-responsive virilizing granulosa tumor.

A case of a progressive virilizing solid granulosa-theca cell tumor producing high testosterone levels that were suppressed to normal by a course of oral contraceptives is presented. In vitro studies demonstrated significant specific follicle-stimulating hormone (FSH) receptors on the tumor. The studies of the biological response to gonadotropins in terms of cyclic AMP generation also indicate that the tumor is responsive to gonadotropic hormones in vitro, and are consistent with the in vivo clinical response. A discussion of the role of gonadotropins in the etiology or maintenance of ovarian tumors is also presented.

Adult↗
PubMed1980

Neonatal survival after traumatic fetal subdural hematoma.

A case is presented of neonatal survival after traumatic fetal subdural hematoma. An unusual fetal heart rate pattern was detected on antenatal monitoring and led to immediate termination of the pregnancy by cesarean section. The fetal heart rate pattern may be secondary to fetal cerebral dysfunction, and its early recognition may result in increased survival when trauma occurs in utero.

Abdominal Injuries↗
PubMed1980

Fetal blood and tissue pH with variable deceleration patterns.

Continuous tissue pH, scalp blood pH, and umbilical artery pH were studied in 89 patients with variable decelerations and 5 control patients in labor. The characteristics of the variable decelerations were analyzed. The deceleration pattern was classified as variable without late component (V), variable with late onset (VLO), or variable with late recovery (VLR). The patterns with a late component showed a greater incidence of falling pH during the decelerations. The VLR pattern was very likely to show a tendency to fetal acidosis and a high incidence of low Apgar scores. Variable decelerations without a late component were found to be innocuous. The VLO was an intermediate pattern, often progressing to the potentially more hazardous pattern of VLR.

Apgar Score↗
PubMed1979

Enzymic memory. Steady state kinetic and physical studies with ascorbate oxidase and aspartate aminotransferase.

Enzymic memory is a kinetic phenomenon observable in double displacement mechanisms. The defining feature of enzymic memory is the occurrence of different rates of transfer for a common transferable group from the substituted enzymes obtained with different donor substrates. Memory behavior was previously demonstrated for both the bovine and human liver rhodaneses (EC 2.8.1.1). Steady state kinetic tests for enzymic memory have now been done with ascorbate oxidase (EC 1.10.3.3) and aspartate aminotransferase (EC 2.6.1.1). The results were positive with ascorbate oxidase, which showed an oxygen reactivity ratio of 1:20:300 for the reduced enzymes obtained with reductate, araboascorbate, and ascorbate, respectively. Results were negative for the aminotransferase tested with the alternate donors glutamate and cysteine sulfinate, with oxaloacetate as the common acceptor. The structural basis of the ascorbate oxidase results was probed by comparison of both the ultraviolet absorption and fluorescence spectra of the oxidized enzyme with those of the reduced forms obtained with ascorbate and reductate. The results are consistent with a conformational basis for the memory phenomenon.

Animals↗
PubMed1979

Fetal blood and tissue pH with moderate bradycardia.

Eleven patients with moderate fetal bradycardia in labor were studied by fetal scalp blood pH, continuous tissue pH, and umbilical arterty pH at delivery. The neonatal outcomes and biochemical data demonstrated that moderate fetal brdycardia does not indicate fetal distress.

Female↗