Search PubMed⌕ Search

Biomedical subjects

T Smith

Publications and source records attributed to T Smith.

At least 523 records · Page 29Linked to original sources
PubMed1992

Bone remodelling does not decline after menopause in vertebral fracture osteoporosis.

There is considerable current interest in whether activators of bone remodelling, such as IL-1 and other cytokines, are involved in the pathogenesis of osteoporosis. We have therefore studied indices relating to remodelling activation in 50 patients with postmenopausal vertebral osteoporosis and 12 with hip fracture osteoporosis in comparison with 25 age- and sex-matched controls. Because of uncertainty regarding the accuracy of current biochemical markers of bone formation with respect to the estimation of whole body rates of bone formation, a 85Sr-based radioisotopic method was used. This method was previously validated by comparison with data obtained after double in vivo labelling of transiliac biopsies taken nearly simultaneously. Bone resorption was estimated from urinary hydroxyproline data. Controls selected for their continued good health showed a progressive and statistically highly significant decline in indices of bone formation with time after menopause. No such decline was seen in the vertebral fracture patients (P less than 0.005). There were no hip fracture patients within 10 years of menopause so this statistical test could not be applied appropriately to them. The hydroxyproline data were consistent with the suggestion arising from the bone formation data that remodelling declines progressively after menopause in the controls but not in the vertebral fracture patients. The data also suggested that these two fracture groups were in more negative calcium balance than the controls, this being particularly marked in the hip fracture cases. Plasma osteocalcin data correlated moderately well with the kinetic measurements of bone formation. It is concluded that vertebral fracture osteoporosis is associated with prolongation of menopausal levels of bone remodelling which is inappropriate by comparison with healthy controls.

Age Factors↗
PubMed1992

Effects of a beta 2-adrenergic agonist, cimaterol and corticosterone on growth and carcass composition of male rats.

1. Growth rate and carcass composition were measured in rats treated with cimaterol or vehicle only for 21 days, with corticosterone administered during the last 7 days of cimaterol or vehicle only treatment. 2. Cimaterol significantly stimulated the amount of protein in the carcass as well as gastrocnemius and plantaris muscles by 9-15%, and decreased carcass fat by 24%. 3. Corticosterone treatment significantly decreased protein in the carcass and soleus, plantaris and gastrocnemius muscles by 13-33%. 4. The catabolic effects of corticosterone on carcass and muscle protein were reduced by pretreatment with cimaterol, suggesting that beta-adrenergic agonists may have some potential use in preventing muscle wasting during stressed states.

Adrenergic beta-Agonists↗
PubMed1992

Transfer of staff training from workshops to group homes: a failure to generalize across settings.

Two experiments were conducted to assess acquisition and generalization of skills acquired in a workshop by trainees who were primary caregivers on the staffs of group homes for developmentally disabled clients. In Study 1, 31 staff trainees received an intensive, 1-week workshop in behavioral theory and treatment techniques. When assessed at the workshop site, these staff trainees showed increased treatment skills, relative to 18 staff trainees who did not participate in the workshop. In Study 2, pre- and postworkshop observations were taken on 53 developmentally disabled clients in group homes where the staff trainees worked. These observations provided no evidence that the workshop had any effect on group home client functioning. Future training programs for caregivers may be more successful if they occur in the group home, involve clients in the home, and enlist the support of supervisory staff, rather than focusing only on primary caregivers.

Activities of Daily Living↗
PubMed1992

Persistent iron overload 4 years after inadvertent transplantation of a haemochromatotic liver in a patient with primary biliary cirrhosis.

An iron-loaded liver from a 20-year-old man with occult haemochromatosis was inadvertently transplanted into a 64-year-old lady with primary biliary cirrhosis. Increased hepatic iron storage was observed in biopsy specimens undertaken at 18, 30 and 36 months after transplantation. Serum iron levels and transferrin iron saturation increased and remained elevated 4 years after surgery. Ferritin levels were also consistently increased. Iron absorption test, performed at 4 years after transplant, was increased at 38%. Our data suggest that an intrahepatic defect in haemochromatosis cannot be excluded, and casts some doubt on the assertion that a precirrhotic haemochromatotic liver can be transplanted without sequelae.

Adult↗
PubMed1992

Whole-body and site-specific bone remodelling in patients with previous femoral fractures: relationships between reduced physical activity, reduced bone mass and increased bone resorption.

1. A new tracer method is described for the non-invasive measurement of bone formation in the proximal femur. The method is based on our previously described whole-body method using 85Sr as the tracer (Reeve, J., Hesp, R. & Wootton, R. Calcif. Tissue Res. 1976; 22, 191-206). It allows correction to be made for long-term exchange processes within the skeleton. 2. The method has been applied in a study of regional and whole-body bone formation in 12 rehabilitated patients who had previously suffered a fracture of the proximal femur. Twelve healthy control subjects were studied, who were selected for their good health and continued physical activity. The aim was to explore the relationship between bone formation and physical activity. 3. Bone formation was similar in the two groups, both regionally and in the whole body. Based on analyses of four cadaver specimens, bone formation in the proximal femur was about one and two-thirds times that in the whole skeleton when related to mass of calcium in the region of interest. 4. Whole-body bone resorption, estimated from five measurements per subject of hydroxyproline excretion in relation to creatinine excretion, was significantly higher in the fracture patients (P < 0.01, Wilcoxon's test). 5. Estimates of current physical activity (and immediate pre-fracture physical activity) were made with a newly devised questionnaire. Historical levels of physical activity (at ages 15-45 years) were determined with Astrom's questionnaire. No bone formation index correlated with any index of physical activity. Urinary hydroxyproline excretion correlated inversely both with current physical activity and historical physical activity (for both regression coefficients P < 0.01). 6. The results are discussed in the light of our current understanding of the control of bone remodelling by the discrete basic multicellular units of bone. The opportunity to study regional bone resorption by the additional use of serial dual X-ray absorptiometry of the same region will in future allow the direct monitoring of the effects of therapeutic interventions which have been designed to prevent contralateral hip fracture.

Aged↗
PubMed1992

Comparison of two methods of quantitation in human studies of biodistribution and radiation dosimetry.

A simple method of quantitating organ radioactivity content for dosimetry purposes, based on relationships between organ count rate and the initial whole body count rate, has been compared with a more rigorous method of absolute quantitation using a transmission scanning technique. Comparisons were on the basis of organ uptake (% administered activity) and resultant organ radiation doses (mGy MBq-1) in 6 normal male volunteers given a 99Tcm-labelled myocardial perfusion imaging agent intravenously at rest and following exercise. In these studies, estimates of individual organ uptakes by the simple method were in error by between +24 and -16% compared with the more accurate method. However, errors on organ dose values were somewhat less and the effective dose was correct to within 3%. These radiation dose effects were largely influenced by radioactivity in the remaining body (i.e. excluding the organs specifically analysed) which accounted for the major proportion of the 99Tcm residence time. Effects due to different biodistributions between rest and exercise studies were also observed and it is concluded that although the simple method was acceptable for the present dosimetry study it should only be used with caution, and a more accurate method is recommended.

Adult↗
PubMed1992

Validation of a method of treating menorrhagia by endometrial ablation.

Menstrual blood loss was measured by intravenous injection of radioactive iron (59Fe) and whole-body counting in 19 women complaining of menorrhagia due to dysfunctional bleeding. Fifteen patients were then treated by radiofrequency endometrial ablation, after which blood loss was re-measured. The majority of the patients were bleeding excessively before treatment (mean 281 (SD 156) ml per cycle averaged over two cycles, range 49-665 ml, n = 19). In the 15 treated patients, average blood loss was reduced to 52 (SD 39) ml per cycle and the mean reduction in blood loss was highly significant (P < 0.001). These quantitative data correlate well with the patients' subjective reports.

Adult↗
PubMed1992

The relative effects of sex and deprivation on the risk of early death.

Socio-economic factors and sex are both known to have a pronounced bearing on the risk of early death. To determine the relative effects of these factors in our Health Board, an analysis was carried out of all deaths under the age of 70 registered in Tayside during 1989 and 1990, by age, years of life lost, diagnosis and postcode sector/deprivation category. A yearly average of 14,520 years of life up to the age of 70 were lost by males compared with 8248 by females. When cancers of the breast and sex organs were excluded, just over a quarter (28 per cent) of the difference was due to the higher death rate in males resulting from injuries and poisoning and another quarter to ischaemic heart disease (23 per cent), with infant deaths in third place (17 per cent). Deprivation category analysis showed that deaths and years of lost life from ischaemic heart disease and injuries and poisoning in males in the most deprived areas were approximately one-third higher than in the most affluent. At the same time, the death rate in males from these causes in each area, from the most affluent to the most deprived, was approximately two and a half to three times as high as in females, as were lost years of life.(ABSTRACT TRUNCATED AT 250 WORDS)

Cause of Death↗
PubMed1992

Brain blood flow and metabolism do not decrease at stable brain temperature during cardiopulmonary bypass in rabbits.

Cerebral blood flow (CBF) during human hypothermic cardiopulmonary bypass has been reported to decrease with time, suggesting that progressive cerebral vasoconstriction or embolic obstruction may occur. We tested the hypotheses: 1) that observed CBF reductions were due to continued undetected brain cooling and 2) that CBF during cardiopulmonary bypass would be stable after achievement of constant brain temperature. Anesthetized New Zealand White rabbits underwent cardiopulmonary bypass (membrane oxygenator, centrifugal pump, bifemoral arterial perfusion) and were assigned to one of three bypass management groups based on perfusate temperature and PaCO2 management: group 1 (37 degrees C, n = 8); group 2 (27 degrees C, pH-stat, n = 9); and group 3 (27 degrees C, alpha-stat, n = 8). Systemic hemodynamics, and cerebral cortical, esophageal, and arterial perfusate temperatures were recorded every 10 min for the first hour of bypass and again at 90 min. CBF and masseter blood flow (radiolabeled microspheres) were determined at 30, 60, and 90 min of bypass, while the cerebral metabolic rate for oxygen (CMRO2) was determined at 60 and 90 min. Groups were comparable with respect to mean arterial pressure, central venous pressure, hematocrit, and arterial oxygen content throughout bypass. Cortical temperature was stable in normothermic (group 1) animals, and there was no significant change in CBF between 30 and 90 min of bypass: 68 +/- 18 versus 73 +/- 20 ml.100 g-1.min-1 (mean +/- SD). In the hypothermic groups (2 and 3), cortical temperature equilibration (95% of the total change) required 41 +/- 6 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Regulation of iron absorption in iron loaded subjects with end stage renal disease: effects of treatment with recombinant human erythropoietin and reduction of iron stores.

The effects on iron absorption of variation in erythroid activity, haemoglobin and iron stores were studied in six anaemic dialysis-dependent subjects in whom iron stores were increased from previous red cell transfusions. Gastrointestinal mucosal uptake and whole body retention of oral iron were measured at the beginning of the study, after starting treatment with recombinant erythropoietin (but before significant increase in haemoglobin), after partial correction of anaemia, after further reduction of iron stores by repeated phlebotomy, and when erythropoiesis decreased from the discontinuation of treatment with erythropoietin. Between successive measurements, valid comparisons were made in five subjects. Correction of anaemia decreased whole body retention of iron through decreased mucosal uptake (P = 0.032). Further reduction in iron stores through repeated phlebotomy whilst the increase in haemoglobin was maintained by treatment with erythropoietin, tended to increase whole body retention of iron through an increase in mucosal transfer (P = 0.010). With initial enhancement of erythropoiesis in anaemic iron-loaded subjects there was no change in any measured component of iron absorption. However, after correction of anaemia and reduction of iron stores, a decrease in erythropoiesis was associated with decreased whole body iron retention in all subjects through decreased mucosal transfer (P = 0.028). The data suggest that anaemia upregulates mucosal iron uptake, and that erythroid activity upregulates mucosal transfer but that this latter effect may be counter-balanced by iron overload which downregulates mucosal transfer.

Adult↗
PubMed1992

First-pass gastric mucosal metabolism of ethanol is negligible in the rat.

Ethanol metabolism by gastric alcohol dehydrogenase (ADH) is thought to be an important determinant of peripheral ethanol time-concentration curves (AUCs) in rats and humans. We quantitated this metabolism in rats by measuring the gastric absorption of oral ethanol (0.25 g/kg) and the gastric venous-arterial (V-A) difference of ethanol versus ethanol metabolites (acetate, acetaldehyde, and bicarbonate). Over 1 h, approximately 20% of the ethanol was absorbed from the stomach and 70% was emptied into the duodenum. The gastric V-A difference of ethanol metabolites was less than 4% of that of ethanol. Thus, gastric metabolism accounted for less than 1% (less than 4% of 20% absorbed) of the dose. This negligible metabolism was predictable from the low affinity of gastric ADH for ethanol. In contrast, gastric ADH has a high affinity for octanol, and 66% of this compound was metabolized during gastric absorption. Evidence supporting gastric metabolism of ethanol largely derives from the lower AUCs observed after oral than after intravenous administration; however, we observed increasingly higher AUCs with increasingly rapid portal vein infusions of identical ethanol doses. We conclude that gastric metabolism of ethanol is negligible in the rat, and differences in AUCs ascribed to gastric metabolism may reflect differences in ethanol absorption.

Absorption↗
PubMed1992

The development of functional and equivalence classes in high-functioning autistic children: the role of naming.

The development of functional and equivalence classes was studied in four high-functioning, preschool-aged autistic children. Initially, all subjects failed to demonstrate match-to-sample relations indicative of stimulus equivalence among two three-member classes of visual stimuli. Then, 2 subjects showed emergence of those relations after they were taught to assign the same name to all members in each class. Next, subjects were taught names for new stimuli outside the match-to-sample format. On subsequent match-to-sample tests, 2 subjects demonstrated untrained conditional relations among the stimuli given a common name. New, unnamed stimuli were then related via match-to-sample training to stimuli from sets of named stimuli. Tests for emergent conditional relations between the new unnamed stimuli and the named stimuli yielded positive results for 1 subject and somewhat mixed results for 3 subjects. Finally, without naming, 2 subjects developed stimulus equivalence among two new three-member classes of visual stimuli. These data suggest that naming may remediate failures to develop untrained conditional relations, some of which are indicative of stimulus equivalence.

Association Learning↗
PubMed1992

An algorithm for the clinical differentiation of malaria and typhoid: a preliminary communication.

The objective of this study was to determine which clinical features of typhoid and malaria are most helpful in distinguishing the two diseases among Papua New Guinean highlanders. In a study of 35 patients with culture-positive typhoid and 49 with blood-slide-positive malaria (Group 1), the odds of typhoid were increased most in patients with altered bowel habit, an illness of more than 2 week's duration, tremor or the presence of typhoid facies. The odds of typhoid were lowest in patients with pallor or jaundice. These findings were used to derive a clinical diagnostic algorithm, which was then evaluated in a further group of 34 typhoid patients and 41 malaria patients (Group 2). The sensitivity of the algorithm in diagnosing malaria was 91% in Group 1 and 71% in Group 2, with specificities of 85% and 79% respectively. For typhoid, the sensitivity of the algorithm was 85% and 79% for Groups 1 and 2, respectively, and the specificities were 91% and 71%. We conclude that the algorithm merits further evaluation in a primary health care setting and may prove useful in making an earlier diagnosis of typhoid.

Algorithms↗