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Biomedical subjects

S Sheppard

Publications and source records attributed to S Sheppard.

12 recordsLinked to original sources
PubMed1992

Exposure of operating room personnel to nitrous oxide during paediatric anaesthesia.

This study was undertaken to quantify the exposure of operating room staff to nitrous oxide during routine paediatric otolaryngeal surgery and to determine the influence of the method of induction of anaesthesia on this exposure. The nitrous oxide exposure of the anaesthetist, the surgeon and the circulating nurse were measured, using body-worn passive atmospheric samplers, during twelve routine paediatric otolaryngeal surgical lists. During six of the lists an inhalational technique, with nitrous oxide, oxygen and halothane, was used for the induction of anaesthesia. During the other six lists anaesthesia was induced using intravenous thiopentone. In all cases, anaesthesia was maintained using nitrous oxide, oxygen and halothane. Regardless of the induction technique used, the mean nitrous oxide exposures of the anaesthetist, the surgeon and the nurse all exceeded the maximum level of 25 ppm.hr-1 recommended by the United States National Institute for Occupational Safety and Health (NIOSH). The use of an intravenous technique for the induction of anaesthesia reduced the nitrous oxide exposure of the anaesthetist and the circulating nurse. This suggests that, although the use of an intravenous induction may reduce exposure to nitrous oxide, the NIOSH recommendations for maximum exposure of operating room personnel to nitrous oxide are currently unattainable in practice.

Adult↗
PubMed1991

Prediction of hearing thresholds in children using an automated toy discrimination test.

A previous paper described the development of the prototype of a semi-automated, sensitive and accurate version of the McCormick Toy Discrimination Test. In this report we describe a further development of the hardware, and demonstrate that results obtained from the automated test provide a basis for estimating the mean elevation of pure-tone threshold in the child's better ear. The correlation between speech and pure-tone results is high. The average of the better ear pure-tone thresholds at 0.5, 1 and 4 kHz can be predicted from the word-discrimination threshold obtained with the toy test, with a 95% confidence interval of +/- 11 dB.

Adolescent↗
PubMed1990

A bolus dose of esmolol attenuates tachycardia and hypertension after tracheal intubation.

Forty-five patients of ASA physical status I and II undergoing a variety of non-cardiac surgical procedures were studied to determine the effect of bolus administration of esmolol, a new short-acting beta blocking drug, on heart rate and blood pressure responses to induction of anaesthesia and tracheal intubation. Subjects were allocated randomly to receive placebo, 100 mg or 200 mg of esmolol IV as part of an anaesthetic induction technique. The differences in heart rate between the placebo group and both the 100 mg and 200 mg groups were significant prior to intubation (95 +/- 7.9, 82 +/- 9.7, 80 +/- 7.3 beats per min respectively), and also at 0.5 min and 1.5 min following intubation for the 200 mg group. In the 200 mg group there was a significant decrease, compared with placebo, in systolic blood pressure at 0.5 min (144 +/- 32.1 vs 165 +/- 18.7 mmHg) and 1.5 min (154 +/- 25.0 vs 170 +/- 19.5 mmHg) after intubation. In this study, adequate haemodynamic control was obtained following administration of 200 mg of esmolol.

Adrenergic beta-Antagonists↗
PubMed1978

Teratogenicity testing in humans: a method demonstrating safety of bendectin.

We investigated the incidence of birth defects in the offspring of women who took Bendectin during pregnancy. Copies of all prescriptions issued for Bendectin in two Cities, Leeds and Liverpool, over periods of 12 and 14 months, respectively, were scanned and a record initiated for each patient. Birth notifications were later searched for matching with indexed patients. Births were traced for 2,298 patients and the incidence of major defects compared with those in the relevant populations. We found no evidence to suggest that Bendectin is teratogenic in humans.

Abnormalities, Drug-Induced↗
PubMed1978

Leucocyte ascorbic acid and pregnancy.

1. Leucocyte ascorbic acid concentrations have been measured in 1147 females during early pregnancy and in smaller numbers of women before conception, throughout pregnancy and at 6 months post partum. 2. The leucocyte concentration in the 1st trimester was found to be affected by season, social class and smoking. Selecting individuals by extremes of social class, season and smoking produced two small populations with almost separate ascorbic acid distributions and mean concentrations of 21.7 and 45.1 microgram/10(8) leucocytes. 3. Early pregnancy had little effect on leucocyte ascorbic acid concentrations but values decreased in the second trimester. However, this was associated with a leucocytosis so that the total leucocyte ascorbic acid content of blood was unchanged. 4. Low ascorbic acid concentrations during the 1st trimester were not associated with subsequent spontaneous abortions, still-births or neonatal deaths, but there was an increased frequency of low values in women who gave birth to infants smaller than 3250 g. 5. The adequacy of ascorbic acid reserves in early pregnancy is discussed.

Adult↗
PubMed1977

Maternal nutrition in early pregnancy.

1. Mean daily nutrient intakes of 195 women in the first trimester of pregnancy were assessed by weighed dietary records. 2. In comparsion with recommended intakes for non-pregnant women aged 18-55 years (Department of Health and Social Security, 1969), more than two-thirds of the subjects were having insufficient energy, iron and cholecalciferol. Unsatisfactory intakes of other nutrients were not uncommon. In relation to recommended intakes for the second trimester (Department of Health and Social Security, 1969), all mothers were having insufficient cholecalciferol and more than 80% of mothers had unsatisfactory intakes of energy and Fe. 3. Intakes appreciably lower than those recommended were associated with the following factors: social classes III, IV and V; maternal age under 20 years; smoking ten or more cigarettes daily; vomiting on more than 3 d/week.

Adult↗
PubMed1976

Parity of women contracting rubella in pregnancy. Implications with respect to rubella vaccination.

Data from the National Congenital Rubella Surveillance Programme showed that 44% of children with congenital rubella reported to the programme were born to primiparae. This high proportion is thought to be due to the fact that there was a two-fold increase in the rate of abortion for rubella in pregnancy for women with two or more children. This higher incidence of congenital rubella in firstborns emphasises the need for rubella vaccination prior to a woman's first pregnancy.

Abortion, Therapeutic↗
PubMed1976

Vitamin deficiencies and neural tube defects.

Serum folate, red cell folate, white blood cell vitamin C, riboflavin saturation index, and serum vitamin A were determined during the first trimester of pregnancy in over 900 cases. For each of these there was a social classes I + II showed the highest levels which differed significantly from other classes, except for serum folate. In 6 mothers who gave birth to infants with neural tube defects, first trimester serum folate, red cell folate, white blood cell vitamin C, and riboflavin values were lower than in controls. In spite of small numbers the differences were significant for red cell folate (P less than 0-001) and white blood cell vitamin C (P less than 0-05). These findings are compatible with the hypothesis that nutritional deficiencies are significant in the causation of congenital defects of the neural tube in man.

Adult↗
PubMed1975

Factors influencing the survival of rat brain tumor cells after in vitro treatment with 1,3-bis(2-chloroethyl)-1-nitrosourea.

The shape of dose-response curves obtained for asynchronous, exponentially growing 9L rat brain tumor cells treated in vitro with 1,3-bis(2-chloroethyl)-1-nitrosourea changed as a function of the drug exposure time. For short treatment times (less than 1 hr), the dose-response curves had shoulders, indicating that the cells may accumulate sublethal damage; however, after longer treatments (greater than 1 hr), little if any shoulder was apparent. The slope of the exponential portion of the dose-response curve increased progressively with treatment periods from 15 min to 2 hr. Longer exposure times (up to 24 hr) produced no further changes in the cell-kill kinetics. Cell survival was directly related to the BCNU exposure dose [o integral t Co(t)dt] and to the amount of bound BCNU per cell. Extrapolation of the curves for these two variables indicated that some BCNU damage accumulates before death occurs. The amount of serum and cell products available in the medium to bind BCNU affected the level of survival; however, there was no evidence that extracellular spontaneous breakdown products or chemical transformation products were involved in the cell-killing mechanism.

Animals↗