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Biomedical subjects

J S Hall

Publications and source records attributed to J S Hall.

At least 19 recordsLinked to original sources

Maternal nutritional status in pregnancy and blood pressure in childhood.

OBJECTIVE: To examine the relation between indices of maternal nutrition during pregnancy, including haemoglobin concentration, skinfold thickness and body weight, and the child's blood pressure at 10 to 12 years of age. DESIGN: Follow up study of children whose mothers had haemoglobin estimations, weights and skinfold thicknesses recorded during pregnancy. SETTING: Kingston, Jamaica. SUBJECTS: Seventy-seven children whose mothers took part in a prospective study of nutrition during pregnancy in relation to fetal growth. MAIN OUTCOME MEASURE: Blood pressure at 10 to 12 years of age. RESULTS: The child's mean systolic pressure adjusted for current weight rose by 2.6 mmHg (95% CI 0.5-4.6, P = 0.01) for each 1 g/dl fall in the mother's lowest haemoglobin during pregnancy. Mothers with a lower haemoglobin had thinner skinfold thicknesses, especially over the triceps (P = 0.005). In multiple regression analyses, taking account of the child's sex and current weight, there was a strong association between thin maternal triceps skinfold thickness at 15 weeks of gestation and raised blood pressure in the offspring. Taking account of the mother's triceps skinfold thickness abolished the relation between lower haemoglobin and raised blood pressure in the child. Lower weight gain between 15 and 35 weeks of gestation was independently associated with raised children's blood pressure. Systolic pressure rose by 10.7 mmHg (95% CI 5.7 to 15.6, P = 0.0001) for each log mm decrease in the mother's triceps skinfold thickness, and by 0.6 mmHg (95% CI 0.1 to 1.0, P = 0.02) for each 1 kg decrease in the mother's weight gain during pregnancy. CONCLUSIONS: These results parallel animal experiments suggesting that impaired maternal nutrition may underlie the programming of adult hypertension during fetal life.

Blood Pressure

Cellular effects of piezoelectric versus electrohydraulic high energy shock waves.

High energy shock waves produced by a piezoelectric lithotripter, (EDAP LT.01) and an electrohydraulic lithotripter, (Dornier HM3) were examined for their effects on Chinese hamster ovary cells in suspension. The EDAP caused acute lactate dehydrogenase release, consistent with severe membrane disruption in a proportion of cells, with the remaining proportion of cells replicating normally as measured by clonogenic assay. Similarly, the Dornier also caused lactate dehydrogenase release. However, a significant proportion of cells which remained "viable" after Dornier treatment, (intact to lactate dehydrogenase), did not replicate by clonogenic assay. The Dornier HM3 lithotripter has been reported to produce free radicals in aqueous solution. In the current investigation, we could not detect significant free radical formation from the EDAP LT.01. Chinese hamster ovary cell killing by the Dornier HM3 was significantly augmented by radiosensitizers, 5-iodo-2-deoxyuridine or buthionine sulfoximine, while radioprotectors cysteamine and WR-1065 had no protective effect. EDAP cell killing was not influenced by either radioprotectors or radiosensitizers. The mechanism of in vitro cytotoxicity differs between piezoelectric and electrohydraulic high energy shock wave delivery.

Animals

Glanzmann's thrombasthenia and pregnancy.

Glanzmann's thrombasthenia is a rare congenital disorder of platelet function manifesting as defective primary haemostasis. Bleeding episodes often require platelet transfusions, and allo-immunization to donor platelets may occur. The problems of ensuring adequate haemostatic potential for delivery of an allo-immunized pregnant female with Glanzmann's thrombasthenia are presented.

Adult

Dietary patterns and nutrition in pregnancy in Jamaica.

During a study of nutrition in pregnancy, the diets of 108 Jamaican pregnant women were assessed by single 24-hour recalls. The women were 16-45 years old, of mixed parity (0-9), attended private (23 per cent) and public (77 per cent) antenatal clinics and differed in stage of pregnancy at interview. Mean energy intake (2110 +/- 739 kcal/d) was low, 83 per cent of the average Recommended Dietary Allowance for the Caribbean (CFNI 1976). Most (76 per cent) women had low energy and dietary iron (75 per cent) intakes. Fewer women had low riboflavin (42 per cent) or protein intakes (29 per cent). Maternal age, parity, obstetric performance, and unusual cravings influenced maternal nutrition to some extent. Dietary assessments overestimated the risk of maternal malnutrition.

Adolescent

Fluorometric calcium measurement.

Measuring the fluorescence of dyes specific for calcium and other cations allows the elucidation of cellular mechanisms such as neurotransmission, muscle contraction and cardiovascular regulation.

Animals

Response of plasma norepinephrine concentration to the vasodepression caused by beta-adrenoceptor antagonists in the conscious spontaneously hypertensive rat.

The subcutaneous administration of a single dose of the beta-adrenoceptor antagonists atenolol, betaxolol, oxprenolol, pindolol, propranolol, or sotalol to conscious spontaneously hypertensive rats (SHR) lowered mean arterial pressure (MAP) by 15-20%, but this vaso-depression was not accompanied by a rise in plasma norepinephrine (NE) concentration. When MAP was decreased at the same rate and to the same extent with the vasodilator minoxidil, plasma NE concentration increased 50-75%. Atenolol, betaxolol, propranolol, and sotalol lowered heart rate, whereas oxprenolol, pindolol, and minoxidil elicited a tachycardia. Atenolol (-48%), betaxolol (-63%), and propranolol (-29%) significantly suppressed plasma renin activity (PRA), and minoxidil elevated PRA by 150-315%. Pindolol (+37%) caused a nonsignificant increase in PRA, and oxprenolol (-23%) and sotalol (-17%) produced nonsignificant decreases in PRA. Because the beta-adrenoceptor antagonists did not increase plasma NE concentration, whereas an equivasodepressor dose of minoxidil did, we conclude that plasma NE concentration is inappropriately low relative to the decrease in MAP caused by beta-adrenoceptor antagonists in the conscious SHR. In addition, the diverse effects of the beta-adrenoceptor antagonists on PRA in SHRs indicate that a suppression of renin release cannot account for either the decrease in MAP caused by these drugs or the failure of plasma NE concentration to increase when MAP is decreased by beta-adrenoceptor antagonists.

Adrenergic beta-Antagonists

Pregnancy in chronic active hepatitis with cirrhosis.

Pregnancy in chronic active hepatitis and cirrhosis is rare. There is an appreciable perinatal mortality and the effect of pregnancy on the underlying liver disease remains uncertain. Two patients with autoimmune chronic active hepatitis with cirrhosis who became pregnant during an active stage of their disease while on therapy are described. Both had an uneventful pregnancy with successful deliveries. One of the patients had two other pregnancies but the pregnancy had to be terminated because of clinical deterioration. With close supervision patients with chronic active hepatitis and cirrhosis may have successful pregnancies.

Abortion, Therapeutic

The effect of propranolol on blood pressure and central MOPEG concentration in the conscious spontaneously hypertensive rat.

The total concentration of the norepinephrine metabolite 3-methoxy-4-hydroxyphenylethyl glycol (MOPEG) and propranolol concentration was measured in the medulla, pons, hypothalamus and thoracic spinal cord of conscious spontaneously hypertensive rats during the development of the antihypertensive effect of a single dose of d,l-propranolol (10 mg/kg s.c.). Propranolol significantly increased MOPEG concentration by 21% in the thoracic spinal cord (2 h) and 16% in the hypothalamus (4 h), but no consistent pattern of change in regional MOPEG concentration was found in relation to the time course of the antihypertensive effect of propranolol.

Animals

Iatrogenic neonatal and maternal hyponatraemia following oxytocin and aqueous glucose infusion during labour.

Maternal and umbilical cord serum sodium and osmolality were studied prospectively in 140 deliveries to investigate whether transplacental hyponatraemia, seen following oxytocin infusion during labour, was due to the antidiuretic effect of oxytocin or was secondary to the infusion of aqueous glucose used as a vehicle for oxytocin, or both. Forty-five women received oxytocin in aqueous glucose for induction or augmentation of labour (oxytocin group), 43 received aqueous glucose infusion alone (glucose group) and 52 did not receive any intravenous infusions (control group). Mean cord sodium levels were significantly lower in the oxytocin (131.4, SD 3.6 mmol/l) and glucose groups (132.5, SD 3.2 mmol/l) than in the control group (135.0, SD 3.0 mmol/l). Hyponatraemia (Na less than 130 mmol) was seen in 47% and 30% of the infants in the oxytocin and glucose groups respectively, in contrast to only 5.8% of the infants in the control group. Significant negative linear correlations were seen between serum sodium and the dose of oxytocin (P less than 0.01) and log of the volume of glucose solution infused (P less than 0.001). The hyponatraemic newborn infants had a significantly higher incidence of transient neonatal tachypnea (7/37, 19%) than the normonatraemic infants (2%). Our results strongly suggest that infusion of oxytocin and glucose both cause maternal and transplacental hyponatraemia, even in recommended doses. This should be taken in account while planning a safe dose of oxytocin and glucose for infusion during labour.

Adult

Whole-body protein turnover in Jamaican women during normal pregnancy.

A cross-sectional study was carried out among 18 Jamaican pregnant women divided into three groups of 6 subjects according to the stage of pregnancy: group B, 12 weeks, group C, 24 weeks and group D, 33 weeks. A group (group A) of 6 non-pregnant women was selected as control. The rate of whole-body protein turnover was measured by continuous oral administration of 15N-glycine and the resting metabolic rate by the open-circuit method. All subjects had a normal pregnancy outcome. The composition of the diet on the day of the study was comparable between the four groups (approximately 80 g protein and 9.45 MJ energy) and not significantly different from the composition of the diet during the 2 d prior to the experiment. The rates of protein synthesis and breakdown were higher in groups B and C compared to group A and lower in group D where they reached values slightly higher than in group A. Estimated from urea enrichment, these rates did not vary significantly among the groups, while estimated from ammonia enrichment the difference was significant (P less than 0.05) and there was a negative correlation between the gestational age and the rate of synthesis (r = -0.63) and breakdown (r = -0.69). Nitrogen retention was comparable between the three groups of pregnant women and significantly higher than in the group A. The resting metabolic rate was similar between the groups of pregnant women. These results suggest that the rates of protein turnover observed during gestation reflect more the changes that occur in maternal than those in fetal tissues. The values for protein synthesis and nitrogen retention indicate that the amount of protein deposited during pregnancy is greater than that expected on the basis of body composition analysis. It is also suggested that as pregnancy proceeds whole-body protein turnover represents a smaller part of the resting metabolic rate.

Adult

Intrapartum infusion of aqueous glucose solution, transplacental hyponatraemia and risk of neonatal jaundice.

Cord serum sodium levels in three groups of 278 singleton infants, born vaginally at term, were correlated with the incidence of jaundice (serum bilirubin greater than or equal to 85 mumol/1) in the first 3 days of life. Of the 278 infants, 87 were born to mothers who were given infusions of 5% or 10% glucose in water during labour (group I), 90 were born to mothers who received glucose solution as a vehicle for oxytocin (group II), and 101 to mothers who did not receive any intravenous fluid therapy (control group). Jaundice was seen significantly more frequently in groups I (28/87, 32%) and II infants (30/90, 33%) than in the control group (12/101, 12%) (P less than 0.01), but when analysed in relation to cord serum sodium levels, the prevalence of jaundice in the normonatraemic infants (serum sodium greater than or equal to 131 mmol/1) was similar in the three groups. On the other hand, in groups I and II jaundice occurred about 3.5 times more frequently in the hyponatraemic infants [group I (17/32, 53%) and II (20/39, 51%)] than in the normonatraemic infants (P less than 0.01). The difference was not associated with any other perinatal or neonatal characteristic.

Adult

Latex agglutination inhibition card test for gentamicin assay: clinical evaluation and comparison with radioimmunoassay and bioassay.

Gentamicin levels were determined in 100 serum specimens by a new latex agglutination inhibition card test, a radioimmunoassay (RIA), and a bioassay. Correlation coefficients determined by linear regression analysis demonstrated that the levels obtained by the latex agglutination inhibition card test had a high degree of correlation with the RIA and could be performed much faster and more economically when processing small numbers of specimens. The bioassay had a slightly lower degree of correlation with both the RIA and the latex test and was adversely influenced by concurrently administered antibiotics which could not be eliminated by beta-lactamase. When measuring gentamicin concentrations above 2 micrograms/ml, the coefficient of variation was less than 14% for the latex agglutination assay compared with 15% for the bioassay and 12% for RIA. The latex agglutination inhibition card test is a rapid, accurate, specific, and reproducible method for monitoring gentamicin levels in patients and is particularly applicable for laboratories processing small numbers of specimens.

Animals