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Biomedical subjects

A Bush

Publications and source records attributed to A Bush.

At least 217 records · Page 12Linked to original sources

Improvement in endocrine and ovarian function during dietary treatment of obese women with polycystic ovary syndrome.

OBJECTIVE: Obese women with polycystic ovary syndrome have a greater frequency of menstrual disturbance and of hirsutism than lean women with the syndrome. Initial studies have demonstrated a marked improvement in endocrine function following a short-term, very low calorie diet. The purpose of this study was to examine the effect of long-term calorie restriction on clinical as well as biochemical abnormalities in obese women with polycystic ovary syndrome. DESIGN: We performed a within-group comparison of clinical and biochemical indices before and during dietary treatment. PATIENTS: Twenty-four obese women with polycystic ovary syndrome (mean weight 91.5 (SD 14.7) kg) were scheduled for treatment for 6-7 months with a 1000 kcal, low fat diet. Nineteen of the 24 had menstrual disturbances, 12 had infertility and 19 were hirsute. MEASUREMENTS AND RESULTS: Thirteen subjects lost more than 5% of their starting weight (range 5.9-22%). In this group there was no significant change in gonadotrophin or total serum testosterone levels but there was a marked increase in concentrations of sex hormone-binding globulin (pretreatment: 23.6 (9.5); post-treatment 36.3 (11.8) nmol/l, P = 0.002) and a reciprocal change in free testosterone levels (77 (26) vs 53 (21) pmol/l, P = 0.009). These changes were accompanied by a reduction in fasting serum insulin levels (median (range) 11.2 (5.2-32) vs 2.3 (0.1-13.8) mU/l, P = 0.018) and the insulin response to 75 g oral glucose. There were no significant changes in these indices in the group who lost less than 5% of their initial body weight. Of the 13 women who lost greater than 5% of their pretreatment weight, 11 had menstrual dysfunction. Amongst these women, nine of 11 showed an improvement in reproductive function, i.e. they either conceived (five) or experienced a more regular menstrual pattern. There was a reduction in hirsutism in 40% of the women in this group. By contrast, in the group who lost less than 5% of their initial weight, only one of the eight with menstrual disturbances noted an improvement in reproductive function and none had a significant reduction in hirsutism. CONCLUSIONS: These data indicate that moderate weight loss during long-term calorie restriction is associated with a marked clinical improvement which reflects the reduction in insulin concentrations and reciprocal changes in SHBG. The improvement in menstrual function and fertility may therefore be consequent upon an increase in insulin sensitivity which, directly or indirectly, affects ovarian function.

Body Mass Index↗

Attitudes towards prenatal diagnosis and carrier screening for cystic fibrosis among the parents of patients in a paediatric cystic fibrosis clinic.

The parents of all children attending the Royal Brompton National Heart and Lung Hospital cystic fibrosis paediatric clinic were asked to complete an anonymous postal questionnaire addressing attitudes towards prenatal diagnosis and population carrier screening for cystic fibrosis (CF); 65% (170/261) of parents responded. Of the respondents, 92% would support the introduction of a population screening test to detect carriers of CF and 19% felt such a test should be mandatory. A total of 64% of CF parents felt they would choose not to have any further children in the knowledge that they were both carriers, 74% would choose to have a prenatal test if they became pregnant, 44% would consider terminating an affected pregnancy, 33% would not, and 23% were unsure. Overall, 72% of respondents indicated they would choose to avoid having a further child with CF either by not having further children or by terminating an affected pregnancy.

Attitude to Health↗

The role of nutrition and insulin in the regulation of sex hormone binding globulin.

In an analysis of 263 women with polycystic ovary syndrome (PCOS), 91 (35%) of whom were obese (body mass index greater than 25 kg/m2), it was found that obese women with PCOS were more likely to be anovulatory and had a higher prevalence of hirsutism than the non-obese subgroup. Although serum concentrations of gonadotrophins, androstenedione and total testosterone were similar in obese and lean women with PCO, sex hormone binding globulin (SHBG) levels were significantly lower, and free testosterone correspondingly higher, in obese women. Serum concentrations of SHBG were inversely correlated with those of both fasting and glucose-stimulated insulin. A short-term, very-low-calorie diet resulted in a 2-fold increase in SHBG which was mirrored by a fall in serum insulin. Similar biochemical changes were also observed during a long-term (6-7 months) 1000 kcal diet and were associated with an improvement of menstrual function and fertility. This encourages the view that calorie restriction has an important part to play in the management of obese women with PCOS.

Androgens↗

Fatal rhabdomyolysis complicating general anaesthesia in a child with Becker muscular dystrophy.

A 6-yr-old boy who presented with brown urine due to myoglobinuria and who was otherwise virtually asymptomatic was diagnosed as having Becker muscular dystrophy on the basis of a greatly elevated creatine kinase, muscle biopsy, dystrophin analysis, and a deletion of exons 3-7 in the dystrophin gene. Fifteen months later, during a general anaesthetic for dental treatment, he had a cardiac arrest associated with acute rhabdomyolysis, hyperkalaemia and hypocalcaemia. He died 4 days later. This case is reported to highlight this rare but potentially fatal complication of anaesthesia in muscular dystrophy, and to discuss possible ways of preventing such a catastrophe.

Anesthesia, Dental↗

Structural flexibility of moral judgment.

One of the central assumptions of Kohlberg's theory of moral development--that moral judgment is organized in structures of the whole--was examined. Thirty men and 30 women were given 2 dilemmas from Kohlberg's Moral Judgment Interview, a 3rd involving prosocial behavior, and a 4th involving impaired driving. Half the Ss responded to the prosocial and impaired-driving dilemmas from the perspective of a hypothetical character, and half responded from the perspective of the self. No sex or perspective differences in moral maturity were observed. Ss scored highest in moral maturity on Kohlberg's dilemmas, intermediate on the prosocial dilemma, and lowest on the impaired-driving dilemma. In partial support of Kohlberg's contention that his test assesses moral competence, there was a negative linear relationship between scores on his test and the proportion of Stage 2 judgments on the 2 other dilemmas. An interactional model of moral judgment is advanced.

Adolescent↗

Tuberculosis in a contact.

A 12 year old girl developed a large tuberculous pleural effusion. She was a contact of an adult with pulmonary tuberculosis who was positive on smear testing, and she had been managed in accordance with current British Thoracic Society recommendations.

Child↗

Pulmonary function in chronic renal failure: effects of dialysis and transplantation.

Many possible pulmonary complications of renal disease have been described, but little is known of their physiological importance or the effects on them of different forms of renal replacement therapy. Four groups were recruited, each containing 20 patients. The groups consisted of patients with chronic renal failure before dialysis (group 1); patients receiving continuous ambulatory peritoneal dialysis, never having received a transplant (group 2); patients receiving haemodialysis, never having received a transplant (group 3); and patients after their first successful cadaveric renal transplant (group 4). All were attending the same regional dialysis and transplant unit. None was known to have clinically important lung or chest wall disease. Flow-volume loops were recorded before and after 400 micrograms of salbutamol, and plethysmographic lung volumes and airway conductance and single breath carbon monoxide transfer factor were measured. Only nine of 80 patients had normal lung function. The reductions in spirometric values were minor. Whole lung carbon monoxide transfer factor was reduced in all groups (mean % predicted with 95% confidence intervals: group 1 81.7% (74-89%); group 2 69.7% (62-77%); group 3 87.5% (80-96%); group 4 82.5% (78-87%]. The values were significantly lower in those having continuous ambulatory peritoneal dialysis (group 2). Residual volume was reduced significantly in the group who had undergone renal transplantation (85.7%, 77-94%). There was no correlation between these changes and smoking habit, age, duration or severity of renal failure, duration of treatment, or biochemical derangement. It is concluded that abnormal lung function is common in renal disease. The main change is a reduction in carbon monoxide transfer that persists after transplantation. The likeliest explanation is that subclinical pulmonary oedema progresses to fibrosis before transplantation. The fibrosis may worsen further to cause the reduced residual volume in the recipients of grafts.

Adult↗

Left bronchial isomerism associated with bronchomalacia, presenting with intractable wheeze.

The cause of the Williams Campbell syndrome (bronchomalacia with bronchiectasis) is controversial. A boy with bronchomalacia, bifid ribs, and left bronchial isomerism presented with intractable wheeze mimicking asthma. The combination of the abdominal, bronchial, and atrial anatomy seen in this child has been described only once previously. The coexistence of these congenital abnormalities in this boy supports a congenital cause for the Williams Campbell syndrome. The need to assess wheezy children critically is emphasised.

Bronchi↗

Interactions between alveolar hypercapnia and epoprostenol on the pulmonary circulation: clinical and pharmacological implications.

Hypoxic vasoconstriction has been the subject of many studies, but little is known about the interaction of hypercapnia and the pulmonary circulation. We performed two haemodynamic studies on each of three patients with pulmonary vascular disease secondary to congenital heart disease. On the first occasion ventilation was inadequate due to technical problems, and the patients were therefore hypercapnic (arterial pCO2 greater than 5.3 kPa). On the second occasion, they were normocapnic. Pulmonary vascular resistance was measured on each occasion while the patients were breathing 100% oxygen (alveolar hyperoxia) and while epoprostenol (prostacyclin) was infused at doses of 5-20 ng/kg/min. Pulmonary vascular resistance was elevated in the presence of hypercapnia and, despite oxygen and epoprostenol, could not be reduced to the levels observed in the normocapnic study. We conclude that hypercapnia causes significant vasoconstriction in infants; and that epoprostenol is a relatively ineffective pulmonary vasodilator in infants who are hypercapnic due to inadequate ventilation. Where possible, respiratory acidosis should be corrected before using oxygen or epoprostenol as a pulmonary vasodilator.

Carbon Dioxide↗

O'-(epoxyalkyl)tyrosines and (epoxyalkyl)phenylalanine as irreversible inactivators of serine proteases: synthesis and inhibition mechanism.

A series of O'-(epoxyalkyl)tyrosines and a carboxy terminal (epoxyalkyl)tyrosine and -phenylalanine were synthesized as potential serine protease inhibitors. N-Acetyl derivatives showed irreversible inactivation vis-a-vis subtilisin, while the N-benzoyl ones were specific toward chymotrypsin. The most potent inactivation of chymotrypsin was achieved by a O'-(3,4-epoxybutyl)-L-tyrosine derivative. The inactivation was shown to be stereospecific since a D derivative led to no irreversible inactivation. Placement of the epoxyalkyl group at the carboxy terminus led to potent rapid inactivation. Under these conditions some of the activity was later recovered. The two classes of inactivators (O'-epoxyalkyl and carboxy-epoxyalkyl) appear to operate by different mechanisms. Most importantly, it was found that irreversible inactivation by O'-(epoxyalkyl)-L-tyrosine only resulted if the carboxy terminus was a substrate (i.e. a compound with free carboxy terminus did not lead to inactivation). The ultimate activity kinetic assay (Daniels, S. B.; et al. J. Biol. Chem. 1983, 258, 15046-15053.) indicated that the epoxyalkyl group on the phenolic oxygen had an optimal length of four carbons with respect to the turnover ratio (the ratio of molecules undergoing turnover compared to those that inactivate the enzyme) for chymotrypsin. A different kinetic assay (Ashani, Y.; Wins, P.; Wilson, I. B. Biochim. Biophys. Acta 1972, 284, 427-434.) demonstrated that substratelike turnover was proceeding at considerably slower rates than for the corresponding true substrates and with rate-limiting deacylation of the acyl-enzyme. Amino acid analysis subsequent to acid hydrolysis demonstrated that Met had been selectively alkylated by the O'-(epoxyalkyl)tyrosine derivative. By contrast, alpha-chymotrypsin inactivated with N-benzoyl-L-Phe-2,3-epoxypropyl ester then subjected to amino acid analysis showed no change in the content of any amino acid that would serve as a potential nucleophile to the inhibitor. Yet, the L-Phe content increased, indicating that a covalent bond had been formed between the inhibitor and the enzyme. Either the bond between the inhibitor and the enzyme did not withstand the hydrolytic conditions and/or there was less than 10% decrease in the amino acids with nucleophilic side chains upon inactivation. Finally, two tripeptides containing O'-(epoxyalkyl)-L-tryosines were synthesized [N-(tert-butoxycarbonyl)-L-alanyl-L-alanyl-O'-(2,3-epoxypropyl)-L-tyrosi ne ethyl ester and N-(trifluoroacetyl)-L-valyl-O'-(2,3-epoxypropyl)-L-tyrosyl-L-valine methyl ester] as potential elastase inhibitors and were found to reversibly and competitively inhibit porcine pancreatic elastase.

Animals↗

Cryptosporidiosis in guinea pigs: an animal model.

Cryptosporidia from natural cryptosporidiosis in guinea pigs were experimentally transmitted to both adult and juvenile guinea pigs. Cryptosporidia were associated with the villi of the ileum, jejunum, and duodenum. Both juveniles and adults were equally susceptible to cryptosporidia, as determined by decreases in villus height, increases in crypt depth, and decreases in villus height/crypt depth ratios, when compared with uninoculated animals. When multiple paired comparisons were made between 2 and 10 days postinoculation, there were significant decreases in villus height/crypt depth ratios with time. A dose study showed that 6-week-old guinea pigs were all infected with doses as low as 325 oocysts per animal. When sampled at weekly intervals postinoculation, guinea pigs had significant evidence of infection up to 2 weeks but had recovered completely by 4 weeks. Guinea pigs mounted a specific humoral immune response against cryptosporidia, as measured by an immunoperoxidase technique. Guinea pigs challenged by reinoculation with cryptosporidial oocysts were completely refractory to reinfection. These studies show that cryptosporidiosis in guinea pigs is a useful small animal model of this disease.

Age Factors↗

Changes in pulmonary circulation in severe bronchopulmonary dysplasia.

Eight patients with severe bronchopulmonary dysplasia underwent cardiac catheterisation. Seven had a pulmonary vascular resistance greater than 3 mm Hg.l-1 min.m2 (mean 8.9, range 2.2-13.8). All had raised intrapulmonary shunts (mean 25.6%, range 5.4-50%, normal less than 5%). Two had a high alveolar dead space, and two had unsuspected congenital heart disease. Epoprostenol (prostacyclin), but not 100% oxygen, caused a significant fall in pulmonary vascular resistance. Death was associated with a high pulmonary vascular resistance and a high shunt. Morphometric studies in three cases showed normal numbers of airways, but increased thickness of bronchial muscle. The numbers of alveoli were reduced and the walls thickened. There was increased medial thickness in small pulmonary arteries with distal extension of muscle. In the oldest child some vessels were obliterated by fibrosis. We speculate that measurements of pulmonary vascular resistance and shunt may have prognostic value; that a trial of pulmonary vasodilators other than oxygen might be worthwhile in patients with poor prognosis; and that abnormalities of the pulmonary circulation contribute to the difficulties of managing patients with bronchopulmonary dysplasia.

Blood Pressure↗

Preoperative measurement of pulmonary vascular resistance in complete transposition of the great arteries.

Transposition of the great arteries is frequently complicated by the early onset of pulmonary vascular disease. It is difficult to measure pulmonary blood flow by the Fick principle because the pulmonary arteriovenous oxygen content difference is small and bronchial blood flow is increased in this condition. In eight patients (mean age 7.7 years, range 3 months to 29 years) with transposition of the great arteries mass spectrometry was used to measure oxygen uptake and predict pulmonary end capillary blood oxygen content. The effects of the bronchial circulation were studied by computer modelling. There was close agreement between pulmonary end capillary and pulmonary vein blood oxygen contents but the resultant percentage difference in arteriovenous content difference was significant (mean (SE of difference)) (14.5(3.8)%). The effect of the bronchial circulation was to give spuriously high estimates of pulmonary blood flow. The error was greatest when oxygen consumption was low and aortic blood was very desaturated.

Adolescent↗

Ipratropium bromide: are patients treated with optimal therapy?

A double-blind crossover placebo controlled study was performed on 20 patients with stable chronic asthma, in order to obtain dose response data to ipratropium bromide (40, 80, 200 micrograms) given by metered dose inhaler. The use of the 200 micrograms dose gave a significantly greater peak effect and duration of action than the recommended standard therapeutic dose of 40 micrograms. There were marked individual variations in response to higher doses. Maximum response detected by spirometry occurred within 24 hours of inhalation, thus patients likely to gain clinical benefit are readily identified. The higher dose was well tolerated by most patients and may have clinical application in the treatment of patients who do not respond to the standard dose regime.

Adult↗