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Biomedical subjects

D Davies

Publications and source records attributed to D Davies.

At least 127 records · Page 7Linked to original sources
PubMed1988

Long-term treatment of Nelson's syndrome with sodium valproate.

Eleven patients with Nelson's syndrome were given sodium valproate (Epilim, Sanofi). Plasma ACTH and cortisol levels were measured under carefully controlled conditions which were designed to eliminate spontaneous fluctuations in ACTH. At 6 weeks all 11 patients were reassessed while taking sodium valproate 600 mg/day; there was then a small but significant (P less than 0.05) reduction in plasma ACTH concentration. Six patients continued to take sodium valproate, and were reassessed at 1 year when five were taking 1200 mg/day and one patient was taking 600 mg/day. At 1 year for these six patients there had been an increase in mean plasma ACTH which was then not significantly different from basal values. The five patients who discontinued sodium valproate were also reassessed at 1 year, when there were no significant differences compared to basal or 6-week values. During therapy with sodium valproate, there were no significant changes in the half-life of plasma cortisol, plasma sodium and potassium concentrations, or serum liver enzymes. Weight gain on sodium valproate was the main reason for patients asking to discontinue therapy. Sodium valproate is not an effective long-term therapy for reducing plasma ACTH for patients with Nelson's syndrome.

Adolescent↗
PubMed1988

Attitudes towards epilepsy in general practice.

Little is known about the attitudes of general practitioners (GPs) towards epilepsy or of the attitudes they attribute to laypersons. Postal questionnaires returned by 50 GPs permitted an analysis of the main sources of their knowledge of epilepsy, the role of GPs in treating patients with epilepsy, the personalities and behaviour of people with epilepsy, and the psychological and social consequences of having epilepsy. The results were compared with a recent Australian survey and the implications for care discussed.

Adult↗
PubMed1987

Bio-medical applications of high performance liquid chromatography (HPLC) with amperometric detection.

Electrochemical detection of eluted solutes in HPLC is now well established as a selective and highly sensitive technique. Measurement of catecholamines and metabolites has been the most popular application with an exponential increase in literature. Recent improvements include the use of diphenylborate for extractions, the introduction of smaller diameter HPLC materials which improve resolution and sensitivity, and the replacement of carbon paste with glassy carbon which now gives a more stable electrode with similar sensitivity. Applications of HPLC with amperometric detection to the determination of drugs, amino acids and peptides are discussed.

Animals↗
PubMed1987

Doppler ultrasound prediction of fetal outcome in twin pregnancies.

The usefulness of pulsed Doppler ultrasound in predicting twin pregnancies destined for unsatisfactory outcomes was examined in 30 twin pregnancies. Fetal flow velocity waveform analysis (systolic/diastolic ratio and pulsatility index) and quantitative analysis in the descending aorta and umbilical artery demonstrated good sensitivity and specificity when compared with biparietal diameter and abdominal circumference measurements. This technique shows some promise as a useful adjunct in the management of twin pregnancies.

Aorta, Thoracic↗
PubMed1987

Ultrasound evaluation of tachycardia-induced hydrops in the fetal lamb.

Nonimmune hydrops was induced in six fetal lambs at 120 days' gestation by right atrial pacing at 300 beats/min. Biochemical, hemodynamic, and Doppler parameters were observed and monitored by real-time ultrasound during the creation (18 to 42 hours) and resolution of hydrops. The significant changes seen were hypoproteinemia (34.3 to 29.0 mg/100 ml), venous hypertension (24.6 to 31.3 mm Hg), decreases in thoracic aorta flow, and decreases in systolic/diastolic ratios in the aorta and umbilical artery. These changes were reversed with the discontinuation of pacing and the resolution of fetal hydrops.

Animals↗
PubMed1987

The routine analysis of some specific isomers of polychlorinated biphenyl congeners in human milk.

A mixture of 14 polychlorinated biphenyl (PCB) isomers of various congeners, representing approximately 70% of all human milk PCBs reported in the literature, was made up to identify and approximate their residues in human milk. Individual isomer levels varied from 5 to 103 nanograms per gram of milkfat with the 2,2',4,4',5,5'-hexachlorobiphenyl isomer as the major PCB contaminant of human milk. PCB isomer numbers 74, 118, 153, 138 and 180 made up approximately 75% of all PCBs as measured by this mixture. There was close agreement of total PCB isomer content in breast milk between electron capture gas chromatography and gas chromatographic mass spectrometry determinations. A major interference was encountered however for PCB isomer no. 52, whose residue level in the breast milk was approximately 3 X higher by gas liquid chromatography than by mass spectrometry.

Canada↗
PubMed1987

Evidence for a direct action of exogenous insulin on the pancreatic islets of diabetic mice: II. Prolonged insulin therapy before islet isolation and perifusion.

24 week old diabetic mice of the C57Bl/Ks (db/db) strain were treated with subcutaneous injections of Ultratard M.C. insulin at a dose of 40 mU/animal rising to 100 mU/animal after 12 weeks. The mean plasma insulin value was 146 +/- 20 microU/ml (n = 6). During this time, the mean body weight of the animals rose significantly (p less than 0.05) and the mean blood glucose concentration fell significantly (p less than 0.005) until a value 2-3 times normal was reached, the insulin dose was then adjusted empirically to maintain hyperglycaemia at this level. Pancreatic islets from these animals, untreated diabetic mice and normal (+/+) mice were isolated by collagenase digest and perifused with a modified Krebs-Ringer medium containing either 3 mmol/L or 15 mmol/L glucose. During glucose challenge, normal islets demonstrated the usual biphasic insulin response, but high glucose levels elicited no response from islets of untreated diabetic mice. Previous treatment of diabetic mice with insulin led to a restoration of the first phase of glucose mediated insulin secretion on perifusion and a significant increase (p less than 0.05) in the second phase. Such an improvement in beta-cell function in the face of prevailing hyperglycaemia, even allowing for the possible mediating effect of a 30% fall in blood glucose, was taken as further evidence for a direct action of exogenous insulin on the islets of diabetic mice.

Animals↗
PubMed1987

Marginal mandibulectomy for malignant disease: indications, rationale, and results.

The theoretical basis for performing marginal mandibular resection, as opposed to segmental resection, is discussed; and criteria are suggested. Results are presented that suggest that, in the treatment of malignant disease around the jaw, although the mortality from other tobacco- and alcohol-related diseases remains high, good functional and cosmetic results can be achieved with no loss of local control.

Humans↗
PubMed1986

Growth patterns of glial cells dissociated from newborn and aged mouse brain with cell passage.

Glial cell cultures derived from newborn and aged (18-month-old) mouse cerebral hemispheres and maintained up to cell passage 11 were characterized immunocytochemically by using glial fibrillary acidic protein (GFA), and biochemically by using glutamine synthetase (GS), for astrocytes, and 2',3' cyclic nucleotide 3' phosphohydrolase (CNP) for oligodendrocytes. We report here the changes occurring during passages 5-11. GS and CNP activities did not significantly change with cell passage in cultures from newborn mouse. In cultures derived from aged mouse, CNP activity did not change significantly whereas GS activity increased severalfold. A characteristic finding in higher cell passages (passage #7) was the loss of GFA-positive stained cells and the appearance of multinucleated cells. We interpret these changes in culture to represent possible signs of cellular senescence.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1986

Placental transfer of naloxone.

Maternal and umbilical venous serum naloxone concentrations were measured after the i.v. (30 mothers) or i.m. (seven mothers) injection of naloxone 400 micrograms. Following i.v. naloxone there was rapid transfer to the fetus and therapeutic plasma concentrations could be expected in 1 or 2 min. However, following i.m. administration, neonatal concentrations were variable. In five non-pregnant volunteers naloxone 400 micrograms i.v. resulted in concentrations greater than 2.5 micrograms ml-1 for up to 30 min. After naloxone 2 mg i.m., a peak was reached at 10 min, followed by slow clearance over several hours.

Female↗
PubMed1986

The use of the fasciocutaneous flap in vaginal reconstruction.

Vaginoplasty in two girls with severe vaginal stricturing due to congenital adrenal hyperplasia is described. The strictures were so tight and long that conventional flap techniques were inappropriate, and long fasciocutaneous flaps from redundant labioscrotal tissue were used. This technique has gained wide usage in plastic surgery, but has not been described previously in this site.

Adolescent↗
PubMed1986

Ultrasound prediction of pulmonary hypoplasia.

Normograms for ultrasound-measured fetal chest and heart circumferences were constructed from 83 normal pregnancies of 24 to 39 weeks' duration. Of six cases at risk for pulmonary hypoplasia, all of whom ultimately proved to have the condition, four fell below the fifth percentile for chest circumferences. Both cases in which the chest circumference was within the normal range had pleural effusions.

Cross-Sectional Studies↗
PubMed1985

Evidence for a direct action of exogenous insulin on the pancreatic islets of diabetic mice: islet response to insulin pre-incubation.

Pancreatic islets were isolated by collagenase digest from normal (+/+) and severely diabetic (db/db) mice of the C57BL/Ks strain. Batches of islets from the diabetic mice were incubated for 1 h at 37 degrees C in Krebs-Ringer medium containing glucose (3 mmol/l), with or without mouse insulin (50 mU/l), before perifusion. When compared with untreated islets from the same digest, pre-incubation of islets from diabetic mice with insulin elicited a restoration of the biphasic insulin response to a glucose challenge which was indistinguishable from the response of the untreated, control islets from non-diabetic mice. Untreated diabetic islets showed no insulin response to glucose challenge, insulin values being very significantly lower than those of either non-diabetic or treated diabetic mouse islets (p = less than 0.005). The restoration of secretion in treated islets of diabetic mice was shown not to be an artefact. These observations provide evidence for a direct, as yet undefined, action of insulin on the beta cell of the diabetic mouse.

Animals↗