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Biomedical subjects

J D Clark

Publications and source records attributed to J D Clark.

At least 109 records · Page 6Linked to original sources
PubMed1988

Investigation of hospital-acquired rotavirus gastroenteritis using RNA electrophoresis.

Rotavirus is a common cause of diarrhoea both in the community and in the hospital. Because of this, it may be difficult to determine whether crossinfection has occurred in the hospital, an important finding as review of hygienic techniques and ward closure may be indicated. We therefore investigated the use of Polyacrylamide gel electrophoresis (PAGE) of the rotavirus RNA genome as a means of distinguishing between rotavirus strains in order to assess its role in the evaluation of apparent hospital-acquired rotavirus diarrhoea. Suspected examples of hospital-acquired rotavirus gastroenteritis were studied on an infectious diseases ward and a general infant ward. PAGE analysis demonstrated that crossinfection had not occurred on the infectious diseases ward, even though this was indicated clinically; a single source outbreak involving 11 patients was confirmed on the general infant ward, as all cases showed an identical rotavirus electropherotype. Following ward closure an endemic rotavirus electropherotype was detected, which affected 17 patients over a 3-month period. Electrophoresis of rotavirus RNA is a useful and practical technique in the analysis of hospital-acquired gastroenteritis and can indicate appropriate clinical action.

Cross Infection↗
PubMed1988

Hypothalamic hypogonadism following major head injury.

Endocrine studies, using the four hypothalamic releasing hormones, gonadotrophin releasing hormone, thyrotrophin releasing hormone, corticotrophin releasing hormone and growth hormone releasing hormone, were performed in 33 males after admission with a major head injury. The test was repeated 7 days later in all 33 patients and after 3-6 months in 21 patients. All patients had a period of unconsciousness followed by post-traumatic amnesia of greater than 24 h. The results obtained from investigating the gonadal axis are reported in this paper. The levels of total and free testosterone, basal FSH and basal LH fell significantly during the first 3 days after injury, when the LH and FSH responses to GnRH achieved their highest peak levels. This hormone pattern has not previously been reported in the gonadal axis and may be a consequence of hypothalamic dysfunction. The severity of the injury was negatively correlated to the testosterone concentration on admission and to the basal and peak FSH concentrations 1 week later. Persistent hypogonadism was found in five of the 21 patients retested after 3-6 months, with low testosterone concentrations and three continued to have an exaggerated LH response to GnRH. Thus major head injury frequently results in hypogonadism shortly after injury, with an increased gonadotrophin response to GnRH. In addition, a substantial minority of patients continue to be hypogonadal after 3-6 months. In view of these findings we strongly suggest that all patients should be endocrinologically assessed at intervals following severe head injury.

Adolescent↗
PubMed1988

Conformational effects of chiral alpha,alpha-dialkyl amino acids. I. C-terminal tetrapeptides of emerimicin containing alpha-ethylalanine.

The syntheses and the crystal structures of the C-terminal tetrapeptide fragments of emerimicin IV and III, Boc-R-EtA-Hyp(Bzl)-Ala-Phol and Boc-R-EtA-Hyp(Bzl)-MeA-Phol, containing the chiral alpha,alpha-dialkyl amino acid, R-alpha-ethylalanine (R-EtA) are reported. The two peptides are isomorphous and assume a 3(10)-helical conformation in the crystal. A comparison of the crystal data on alpha,alpha-dialkyl amino acids indicates that alkyl substituents larger than a methyl group do not preclude peptides containing these amino acids from assuming the conformations associated with minima which have been well characterized for alpha-methylalanine.

Anti-Bacterial Agents↗
PubMed1988

Computerized and telemetric management of diabetic pregnancy in Cambridge.

In order to optimize the quality of our care, we have used the Ames Memory Glucometer in our computerized management of 17 insulin-dependent diabetic pregnancies. Patients measured their own blood glucose levels on 4.5 +/- 1.2 (SD) occasions per day, and six of them transmitted their blood glucose measurements telemetrically from home into a hospital-based computer on a total of 42 occasions. We achieved near-optimal blood glucose levels and normal HbA1 levels throughout most of these 17 pregnancies. Average blood glucose levels were 6.4 +/- 0.9 mmol/l in the first, 5.9 +/- 1.2 mmol/l in the second, 5.4 +/- 1.0 mmol/l in the third trimester. Corresponding values for HbA1 were 8.0 +/- 1.5%, 6.5 +/- 0.8%, and 6.2 +/- 0.4%. Average insulin requirement doubled during pregnancy, but fell to 74% of the pre-pregnancy dosage by one week after delivery. The average gestational age at delivery was 38.9 +/- 1.3 weeks, and we had no perinatal deaths. Two of the babies were macrosomic, even though their mothers had good diabetic control. Four patients were delivered by Caesarean section. However we achieved a vaginal delivery in 93% of those in whom it was planned. Our computerized system of managing diabetic pregnancies was efficient, safe, and popular with our patients.

Blood Glucose↗
PubMed1987

Pituitary apoplexy: an unusual cause of stroke.

A case of pituitary apoplexy complicated by hemiparesis and dysphasia is reported. Investigations revealed complete obstruction of the left internal carotid artery due to haemorrhagic pituitary expansion. This case and the four previously reported suggest that early diagnosis of this rare complication is essential if surgery is to prevent cerebral infarction.

Adult↗
PubMed1987

Pulsatile secretion of TSH in healthy subjects.

The physiological variations in serum TSH concentration have been investigated using an enzyme amplified immunoassay with improved sensitivity and precision. Blood samples were collected at regular intervals from 10 healthy volunteers during the period 1800 h to 0100 h. Spectral analysis followed by periodic regression analysis demonstrated significant serum TSH pulsatility with periodicities of 60 or 85-100 min. In addition, a significant (P less than 0.001) evening rise in serum TSH concentration was demonstrated in all subjects, with levels rising at around 21.30-22.00 h.

Adult↗
PubMed1987

Thyroid stimulating hormone measurement by an ultrasensitive assay during thyroxine replacement: comparison with other tests of thyroid function.

Serum thyroid stimulating hormone (TSH) was measured using a highly sensitive enzyme-amplified immunoassay in 37 clinically euthyroid patients receiving thyroxine replacement therapy and compared with other biochemical tests of thyroid function. A highly significant correlation (P less than 0.001) was found between the basal serum TSH and the increase in serum TSH concentration 20 min after the administration of thyrotropin releasing hormone (TRH). The basal serum TSH was negatively correlated with the serum total thyroxine (P = 0.05). When patients results were classified as abnormal or normal many discrepancies were noted between the various thyroid tests. A suppressed serum TSH was found in 65% of patients with a normal serum total thyroxine. However, in patients on thyroxine replacement therapy a basal TSH measured by enzyme-amplified immunoassay provides the same information as a TRH test.

Female↗
PubMed1987

Small area analysis: a review and analysis of the North American literature.

Variations in health service use rates by geographic area have long interested researchers and policymakers. Typically, investigators comparing population-based health care utilization rates among geographic areas have demonstrated substantial variations in use among seemingly similar communities. One method of investigation is "small area analysis." Numerous areas in North America have been studied extensively using this technique. This research has attempted to document the amount of variation found in health care use rates among areas; determine whether or not there is a pattern to such use in high- versus low-use areas; and identify the variables that are associated with the variation and explain a portion of the variation. Beyond this, many researchers have attempted to ascertain whether such variables are associated with characteristics of the population, whether they reflect differences in access and need, or whether a substantial portion of the variation is associated with differences in the medical care system itself. This review discusses the methods used to define the areas, the dependent variables that have been studied and the patterns found within them, the independent variables that have been tested, the statistical methods and analysis procedures used, the results of each study, and the policy recommendations emanating from the research. More importantly, based on what has been learned, the paper provides researchers in small area analysis with a set of recommendations for both analyzing and reporting results. These recommendations are designed to facilitate the development of a common research methodology, increase the comparability across studies, and enhance the use of this technique in the health policy formulation process.

Bibliographies as Topic↗
PubMed1986

Induced aflatoxicosis in rabbits: blood coagulation defects.

The effect of acute and subchronic experimental aflatoxicosis on blood clotting activity and platelets was evaluated. Male New Zealand White rabbits (weighing 2.4-3.2 kg each) were used. In Experiment 1, 19 rabbits were given orally 0.05 mg of aflatoxin B1 (AFB1)/kg of body weight daily from Day 0 through Day 23. Blood samples were collected before dosing and on Days 2, 5, 9, 12, 16, 19, and 23 of the experimental period. In Experiment 2, 40 rabbits were given a single dose of 0.4 mg of AFB1/kg of body weight. Blood samples were collected before dosing and at 12, 24, 36, and 48 hr after dosing. When compared to baseline and control animal values, one-stage prothrombin times and activated partial thromboplastin times of aflatoxin-dosed rabbits were lengthened, and there was a statistically significant decrease in fibrinogen, Factor IX, VIII, and V activities. Platelet counts were significantly increased in subacutely exposed rabbits, and platelet size was decreased in single high-dose treated groups. Factor deficiencies were attributed to a combination of decreased factor synthesis from hepatic insufficiency and consumptive coagulopathy or primary fibrinolysis.

Administration, Oral↗
PubMed1986

Craniopharyngioma with hyperprolactinaemia due to a prolactinoma.

A case is presented in which a histologically proven prolactin secreting pituitary macroadenoma was associated with a large suprasellar craniopharyngioma. The pre-operative prolactin concentration was 8180 mU/l. Although hyperprolactinaemia up to 3000 mU/l in patients with a craniopharyngioma is usually due to stalk compression, greater values may indicate an associated prolactinoma.

Adenoma↗