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Biomedical subjects

P Fletcher

Publications and source records attributed to P Fletcher.

At least 19 recordsLinked to original sources
PubMed1992

Gastric bypass for treating severe obesity.

Gastric bypass (RY-GBP) has a very small gastric pouch with a 1-cm diameter Roux-Y gastrojejunostomy. RY-GBP is associated with early satiety and an aversion to sweets secondary to dumping syndrome symptoms and has a significantly better weight loss than various gastroplasty procedures, including the vertical banded gastroplasty. However, it may be associated with vitamin B-12 deficiency and iron deficiency anemia in menstruating females, preventable with prophylactic oral iron and vitamin B-12. With an 80% 5 y follow-up, RY-GBP patients lose two-thirds of their excess weight within 2 y, 60% at 5 y, and greater than 50% at 9 y. The RY-GBP can be beaten by nibbling "junk foods" (potato or corn chips). Conversion to a malabsorptive procedure may cause severe malnutrition and fat-soluble vitamin deficiencies and should be used only for "superobese" patients who fail a standard RY-GBP and have severe comorbidity. RY-GBP is the most effective procedure for morbid obesity, especially in patients addicted to "sweets."

Gastric Bypass↗
PubMed1992

Cardiac responses after norepinephrine-induced ventricular hypertrophy in rats.

The increase in norepinephrine (NE) blood levels in human heart failure correlates with prognosis. In this study, we determined whether continuous NE infusion alters the positive inotropic and chronotropic responses of isolated rat cardiac muscles. Osmotic minipumps were implanted subcutaneously (s.c.) in 43 adult male rats to deliver NE (160 micrograms/kg/h for 14 days); 42 rats were sham-operated. Isolated left and right atria and left and right ventricular (LV, RV) papillary muscles were prepared to measure positive inotropic or chronotropic responses to NE, phenylephrine, forskolin, dibutyryl cyclicAMP (dbcyclicAMP), and calcium chloride. NE infusion caused (a) a 22% increase in LV wet weight without altering atrial or RV wet weights; (b) an 18% decrease in maximal inotropic response to calcium chloride in LV papillary muscles only; (c) a significantly decreased peak response to NE [72 +/- 5 vs. 93 +/- 5% (sham rats) of calcium chloride] but not to forskolin or dbcyclicAMP in RV papillary muscles; (d) an increased incidence of ectopy at low concentrations of NE, forskolin, and dbcyclicAMP in LV papillary muscles; (e) no alteration in papillary muscle responses to phenylephrine but significantly increased left atrial inotropic responses [51 +/- 5 vs. 33 +/- 2% (sham rats) of calcium chloride] and right atrial chronotropic responses [30 +/- 2 vs. 18 +/- 4 (sham rats) beats/min]; and (f) a selective decrease in beta 1-adrenoceptor density in both ventricles. Thus, NE infusion causes selective LV hypertrophy; responses of compounds that increase intracellular cyclicAMP are affected to a greater extent in papillary muscles from the hypertrophied ventricle than in tissues from the other chambers of the heart.

Animals↗
PubMed1992

The effect of the distance from the contact point to the crest of bone on the presence or absence of the interproximal dental papilla.

This study was designed to determine whether the distance from the base of the contact area to the crest of bone could be correlated with the presence or absence of the interproximal papilla in humans. A total of 288 sites in 30 patients were examined. If a space was visible apical to the contact point, then the papilla was deemed missing; if tissue filled the embrasure space, the papilla was considered to be present. The results showed that when the measurement from the contact point to the crest of bone was 5 mm or less, the papilla was present almost 100% of the time. When the distance was 6 mm, the papilla was present 56% of the time, and when the distance was 7 mm or more, the papilla was present 27% of the time or less.

Alveolar Process↗
PubMed1991

Comparison of inotropic and chronotropic responses in rat isolated atria and ventricles.

1. The positive inotropic and chronotropic responses to adrenoceptor agonists (noradrenaline, phenylephrine), to compounds which increase cAMP by post-adrenoceptor mechanisms (forskolin, theophylline and dibutyryl cAMP) and to calcium chloride were measured in isolated rat atria and papillary muscles from both ventricles. 2. Noradrenaline produced similar maximal inotropic responses to calcium chloride in all tissues. Forskolin gave similar responses to calcium chloride in atrial but not ventricular tissues; the reverse was observed with dibutyryl cAMP. Phenylephrine and theophylline produced significantly smaller inotropic responses than calcium chloride in all tissues, especially in ventricular tissues. 3. Maximal chronotropic responses to noradrenaline, theophylline and dibutyryl cAMP were similar. Forskolin produced significantly greater responses while calcium chloride and phenylephrine produced significantly smaller responses than noradrenaline. 4. These results show that the maximal positive inotropic response of some agonists is markedly dependent on the tissue chosen. Further, chronotropic responses in right atria do not mimic inotropic responses in left atria.

Animals↗
PubMed1990

Bioelectrical impedance, anthropometry and body composition in stunted and non-stunted children.

Bioelectrical impedance (BIA) and anthropometric measurements were taken of 129 stunted and 32 non-stunted children aged 9-24 months in Kingston, Jamaica. The reliability of BIA in such young children was examined and the relationships between impedance and anthropometry were determined. The stunted children had significantly lower body mass index (BMI) and smaller triceps skinfolds than the non-stunted children, suggesting differences in body composition between the groups. Resistance was significantly higher in the stunted children than the non-stunted children and nutritional group (stunted or non-stunted) contributed significantly to the variance in resistance after controlling for length, weight, mid-upper arm circumference, triceps and subscapular skinfolds, age and sex. This suggests that there were differences in body composition and/or body shape between the groups beyond that measured by the anthropometric indices used. Total body water (TBW) was estimated using an equation for Jamaican children of comparable age. As a percentage of body weight the TBW estimates were the same for the two groups, a finding which is inconsistent with the anthropometric data.

Anthropometry↗
PubMed1989

Stunting, severe malnutrition and mental development in young children.

The association was examined between an episode of severe malnutrition, stunting in length and children's developmental levels. Twenty-nine children aged between 6 and 24 months, who had recently recovered from severe malnutrition, were compared with 29 children matched for age and height who had never had an acute episode, and who came from similar social backgrounds. Both groups were given developmental assessments on the Griffiths Test, and their developmental quotients (DQs) were not significantly different. Both groups' DQs were significantly lower than a third group of 15 non-stunted children. It was concluded that the poor developmental levels usually found in severely malnourished children may be largely explained by factors associated with stunting, rather than the acute episode.

Child Development↗
PubMed1987

Differences in mortality from acute myocardial infarction between coronary care unit and medical ward: treatment or bias?

To analyse the effectiveness of coronary care units in reducing mortality from myocardial infarction 18 hospitals ranging from large urban teaching hospitals to small country hospitals were stratified into four levels of care. Previous analysis had failed to show significant differences in the overall mortality in hospital among levels. There were significant differences in mortality, however, between those patients allocated to be cared for in the coronary care unit and those in the medical wards in the more advanced hospitals. The differences were largest in the hospitals with the most elaborate facilities (level 1) and non-existent in those with the least (level 4). Several analytical approaches to these observed differences indicated that they were: (a) reduced by adjustment for age and severity of infarction; (b) paralleled by differences in coexisting disease recorded on death certificates; (c) no longer significant at level 1 after allowing for differences in coexisting disease; and (d) not significant at any level after exclusion of patients first diagnosed at necropsy. These findings suggest that the observed differences in mortality between coronary care units and medical wards are largely due to bias in selection and diagnosis.

Age Factors↗
PubMed1987

Mortality from myocardial infarction in different types of hospitals.

Hospitals ranging from large urban teaching hospitals to small country hospitals were stratified into four levels of care and examined for their effectiveness of coronary care in relation to these levels. The crude hospital mortality among 2265 patients admitted for definite or possible acute myocardial infarction was 21% at level 1 (the most elaborate level), 22% at level 2, 21% at level 3, and 19% at level 4 (the least elaborate). Adjustment for age or other prognostic factors produced no significant differences across levels either for coronary care unit care or for combined coronary unit and ward care. Success in resuscitation was also similar across levels. These findings suggest that increased resources for coronary care units--whether for new services or for upgrading existing ones--may not be required.

Age Factors↗
PubMed1986

Self-association of local anaesthetic drugs in aqueous solution.

The aggregation characteristics of a series of local anaesthetic drugs in water and electrolyte solution have been examined using total intensity light scattering, photon correlation spectroscopy and vapour pressure osmometry. The association of cinchocaine hydrochloride was micellar. An appreciable increase in the effective diffusion coefficient as solutions of cinchocaine were diluted close to the critical micelle concentration was observed and has been discussed. The association of amethocaine hydrochloride could be described using a co-operative stepwise association model. No association could be detected in water or 0.1 mol dm-3 electrolyte for butacaine hemisulphate and the hydrochlorides of procaine, proparacaine, mepivacaine, lignocaine, bupivacaine and prilocaine at drug concentrations of less than 0.2 mol dm-3.

Anesthetics, Local↗