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Biomedical subjects

B Payne

Publications and source records attributed to B Payne.

At least 37 records · Page 2Linked to original sources
PubMed1982

Increased shunt through the patent ductus arteriosus after surfactant replacement therapy.

Instillation of surfactant into the trachea of preterm infants with respiratory distress syndrome is associated with a 90% incidence of patent ductus arteriosus. We studied the effects of surfactant therapy on the ductus arteriosus in 12 preterm lambs. Flow across the ductus arteriosus and systemic blood flow were calculated from radioactive microsphere injections. All developed respiratory failure (pH less than 7.1, Paco2 greater than 60) by 30 minutes after birth. Between 30 and 60 minutes after birth, six lambs were treated with tracheal instillation of 50 mg/kg surfactant lipid. By two hours after birth, treated lambs differed significantly from controls in pH (7.27 +0.02 vs 6.97 +0.08) and Paco2 (43.3 +4.1 vs 85 + 15). There were no differences in Pao2 or PGE2 concentrations or ductus arteriosus resistance, but there was a significantly larger shunt through the ductus arteriosus in treated lambs. This increased shunt resulted from the significant drop in pulmonary vascular resistance and not from a change in patency of the ductus arteriosus. Surfactant replacement may require interventions directed specifically at the patent ductus arteriosus in sick preterm infants.

Animals↗
PubMed1981

Effects of antenatal glucocorticoid administration on ductus arteriosus of preterm lambs.

We have previously shown that the incidence of patent ductus arteriosus (PDA) in premature infants whose mothers received prenatal glucocorticoid therapy was significantly lower than that of an untreated group. In addition, the incidence of respiratory distress syndrome was lower in the treated than in the untreated group. To determine whether glucocorticoids affect the ductus arteriosus itself, we studied the effects of a 48-h intravenous infusion of 1 mg/h hydrocortisone in prematurely born lambs (120-129 days, 0.84 gestation). Estimations of ductus patency were made on 1-h-old lambs by radioactive microsphere injections. We found that hydrocortisone infusions facilitate the closure of the ductus without altering the severity of respiratory distress in premature lambs. In the lamb, prostaglandin E2 (PGE2) inhibits the ability of the ductus to contract in response to O2. Because production of PGE2 has been shown to be inhibited by hydrocortisone in several isolated organ systems, we measured PGE2 plasma concentrations in treated and untreated animals. We found circulating PGE2 concentrations to be similar in the two groups; furthermore, release of PGE2 by isolated ductal rings in vitro was similar in treated and untreated animals. This contradicts the hypothesis that diminished PGE2 concentrations, either circulating or in the tissue, are the cause for ductus arteriosus closure in hydrocortisone-treated animals. However, hydrocortisone treatment decreases the sensitivity of the ductus arteriosus in vitro to the relaxing action of PGE2. These findings suggest that glucocorticoid treatment decreases the incidence of PDA in premature infants by affecting the interaction of PGE2 with ductal tissue.

Animals↗
PubMed1980

Toxicology of various pesticides and their decomposition products on mitochondrial electron transport.

The effect of various pesticides and derivatives on mitochondrial electron transport systems was assessed. DDT, DDE, TDE, Kelthane, chlorobenzilate, chloropropylate and Acarol were found to be inhibitory towards both heavy beef heart mitochondrial (HBHM) NADH-oxidase and succinoxidase enzyme systems. Dichlorobenzophenone and p-chlorophenol were less inhibitory towards the HBHM NADH-oxidase and did not inhibit the succinoxidase enzyme system. DDA did not inhibit either of the electron transport systems. Carbaryl was not inhibitory towards both HBHM oxidase systems, whereas its degradative product dihydroxynaphthalene was inhibitory at the same concentration. Furadan, Matacil, Baygon and Dimetilan were only slightly inhibitory towards themitochondrial NADH-oxidase system and did not inhibit the succinoxidase system. Zectran was inhibitory towards the NADH-oxidase system and was not inhibitory towards the succinoxidase system. DDT, DDE and TDE, dihydroxynaphthalene and 1-naphthol inhibited the NADH-oxidase enzyme system onthe substrate side of cytochrome c, whereas Kelthane inhibited on the oxygen side.

Animals↗
PubMed1979

A new simple assay for total blood lipids by refractometry.

A fast simple method for assay of total blood lipids has been devised by precipitating blood proteins with methanol and extracting lipids into diethyl ether. The change in refractive index of the methanol-ether due to dissolved lipids is measured in a refractometer.

Chemical Phenomena↗
PubMed1978

High-density and low-density lipoproteins and prevalence of vascular disease in diabetes mellitus.

The prevalence of vascular disease among 154 diabetic patients was analysed in relation to the serum concentrations of individual lipoproteins. Overal the presence of vascular disease (59 cases) was positively associated with serum cholesterol and low-density-lipoprotein cholesterol but negatively associated with high-density-lipoprotein (HDL) cholesterol. The negative relation between HDL and vascular disease was not observed in all subgroups of diabetics. We conclude that there may be no overriding association between HDL and vascular disease in diabetics as proposed for some non-diabetic populations.

Aged↗
PubMed1978

Interrelationships of physician performances: technical quality and utilization and implications for quality and utilization controls.

The study determined the intrarelationships and interrelationships of two sets of physician performance measures: technical quality and utilization of medical resources. The performance measures were based on 2,431 episodes in 15 diagnostic categories involving 454 physicians. A series of correlations were used to determine these relationships. The technical performance of physicians for prehospitalization, hospitalization, and posthospitalization care were found to be positively related (r=.38). The interrelationships between efficient utilization and technical quality were also positive (r=.22). There appears to be some homogeneity in the performance in the areas of technical quality and utilization patterns, but this is not strong enough to allow substitution one for another. It is therefore recommended that efforts to control or measure quality of care and utilization patterns need to be directed to each aspect of physician performances.

Comprehensive Health Care↗