Search PubMed⌕ Search

Biomedical subjects

R L Scott

Publications and source records attributed to R L Scott.

At least 19 recordsLinked to original sources
PubMed1999

Intravenous thyroid hormone supplementation in heart failure with cardiogenic shock.

BACKGROUND: Thyroid hormone level abnormalities commonly exist in severe heart failure and may be of prognostic value. The therapeutic potential of using thyroid hormone for cardiogenic shock resulting from progressive heart failure has not been previously delineated. We sought to evaluate the role of an intravenous infusion of thyroxine as an adjunct to conventional inotropic agents and intra-aortic balloon counterpulsation in patients with severe heart failure with cardiogenic shock. METHODS AND RESULTS: We studied 10 consecutive patients with severe systolic heart failure that progressed to a cardiogenic shock state unresponsive to conventional pharmacological inotropic measures. Intravenous thyroxine (20 micrograms/h) was used as an adjunctive salvage measure after the failure of conventional pharmacological and mechanical support by intra-aortic balloon pump. The invasive hemodynamic profile (right atrial pressure, pulmonary capillary wedge pressure, cardiac index, mean arterial pressure), overall clinical status, core temperature, renal function, and tachyarrhythmias were compared before and sequentially at 6, 24, and 36 hours after the initiation of thyroxine administration. Long-term outcome was also defined. All patients had statistically significant improvements in cardiac index, pulmonary capillary wedge pressure, and mean arterial pressure at 24 and 36 hours post-initiation of thyroxine. No sustained tachyarrhythmias were seen during the thyroxine infusion. In 9 of 10 patients who underwent left ventricular assist device placement and/or heart transplantation, the use of thyroxine served as an effective adjunctive measure to allow transitioning to definitive surgical therapy. The 6-month and 1-year cohort survival rates, achieved by the transition to surgical therapy, were 90% and 80%, respectively. CONCLUSION: The beneficial hemodynamic properties of intravenous thyroid hormone can be effectively used in otherwise terminal situations of cardiogenic shock, and in such situations, the use of thyroid hormone can serve as a pharmacological adjunct to a definite surgical intervention. Further studies in larger numbers of patients might be warranted to confirm these findings.

Adult↗
PubMed1996

Relevance of body weight to apolipoprotein levels in Australian children.

OBJECTIVES: To assess weight and apolipoprotein profiles in a representative sample of primary school children. PARTICIPANTS AND SETTING: 1543 children (936 girls and 607 boys) aged 6-11 years from schools in the Eastern Sydney Area Health Service region in 1994. METHODS: We measured body mass index (BMI) and capillary blood apolipoprotein (apo) B and A-I levels (the carrier proteins for low and high density lipoprotein cholesterol, respectively) as well as lipoprotein (Lp) (a). We related BMI levels to those documented in the 1985 Australian Council on Health, Physical Education and Recreation (ACHPER) survey of school children. RESULTS: Compared with the ACHPER distribution, BMI was increased in the boys but not in the girls; 16.8% of boys were above the 90th percentile of the ACHPER distribution (P = 0.003) and only 6.5% were below the 10th percentile (P = 0.046). There were 45 boys (7.4%) and 53 girls (5.7%) with BMIs above the 95th percentile who were, by definition, obese. They had highly significant increases in apo B (P = 0.003) and apo B: apo A-I ratio (P = 0.0001) compared with children in the normal BMI range (10th-90th percentiles); and 20% of the population, including the obese group, also had Lp(a) levels greater than 300 mg/L. The results in children aged 10 and 11 years were not different from those of the whole group, consistent with an absence of possible confounding effects due to early puberty or smoking. CONCLUSIONS: There was an increase in weight relative to height in boys aged 6-11 years in eastern Sydney, compared with the 1985 ACHPER survey. In both boys and girls with the highest BMI category, levels of apo B and the apo B: apo A-I ratio were significantly increased. As these apolipoprotein changes are correlated closely with early onset atherogenesis and are correctable, their identification offers prospects for prevention.

Apolipoproteins↗
PubMed1994

Altered hepatic catabolism of low-density lipoprotein subjected to lipid peroxidation in vitro.

Recent evidence suggests that oxidatively modified forms of low-density lipoprotein (LDL) may be particularly atherogenic. In this investigation, the catabolism of human LDL modified by lipid peroxidation in vitro was studied with a recirculating rat liver perfusion system. A dual-labelling technique was used that permitted native LDL and modified LDL to be studied simultaneously in the liver perfusion system. Native human LDL was found to have a fractional catabolic rate (FCR) of 1.00 +/- 0.21%/h, in agreement with other investigators. Subjecting LDL to oxidation for 12 h in the presence of 30 microM FeEDTA did not significantly affect its FCR. LDL treated with a superoxide-generating system (xanthine oxidase, hypoxanthine, O2) in the presence of 30 microM FeEDTA did, however, show a significant increase in FCR (3.23 +/- 0.19%/h). The hepatic uptakes of native LDL and LDL oxidized with FeEDTA+O2 were similar, but both were significantly lower than the hepatic uptake of LDL treated with the superoxide-radical-generating system. The proteolysis of LDL with pancreatin did not influence either its susceptibility to oxidation or its FCR. LDL oxidation resulted in the preferential loss of alpha-tocopherol rather than gamma-tocopherol. These data indicate that the rat liver effectively catabolizes LDL oxidatively modified by treatment with the superoxide-generating system. Furthermore, our results suggest that only very low plasma levels of highly oxidized LDL could be found under conditions in vivo. The liver may therefore play a major role in protecting the arterial vasculature from highly atherogenic forms of LDL.

Animals↗
PubMed1994

Lipoprotein alterations in the spontaneously hypertensive rat fed diets deficient in selenium and vitamin E.

Both vitamin E and selenium (Se) are antioxidant nutrients that play important roles in preventing in vivo lipid peroxidation. In this investigation, Se and vitamin E were found to influence lipoprotein levels in the spontaneously hypertensive rat (SHR). Four-week-old inbred SHRs were fed a basal (B) diet with 1% cholesterol deficient in both selenium and vitamin E (B+cho diet) or identical diets to which either vitamin E (B+E+cho) or selenium (B+Se+cho) or both micronutrients were added (B+Se+E+cho). Plasma-cho and lipoprotein-cho levels were measured after 6, 12, 16, and 18 weeks of feeding the experimental diets. Rats fed the B+cho diet for at least 12 weeks had plasma-cho levels about twice that observed for rats fed the B+E+Se+cho diet. Plasma-cho levels for rats in the two Se deficient groups (B+cho and B+E+cho) were, however, similar at any time point. Se deficiency was associated with increased plasma-cho, very low density lipoprotein-cho (VLDL-cho) and low-density lipoprotein-cho (LDL-cho). Vitamin E supplementation interacted with Se deficiency to increase plasma VLDL-cho levels. Neither vitamin E alone nor the interaction between vitamin E and Se consistently influenced LDL-cho levels. The percent cholesteryl ester in LDL from rats fed the Se-deficient diets (B+cho or B+E+cho) was at least twice that observed for rats fed the B+E+Se+cho diet. Plasma lipid peroxidation products were highly elevated in rats fed the B+cho diet compared with values for the B+E+cho or the B+E+Se+cho fed rats (which were not significantly different). These results suggest that dietary Se deficiency increases plasma-cho, VLDL-cho, and LDL-cho levels by a mechanism that may be unrelated to its role as an antioxidant nutrient.

Animals↗
PubMed1993

Somatization and malingering for workers' compensation applicants: a cross-cultural MMPI study.

A post hoc analysis was conducted of 60 Hispanics and 60 Caucasians who had filed claims under workers' compensation. The study examined cross-cultural differences of somatization and malingering as assessed by the MMPI. Somatization was assessed by analyzing two- and three-point code types based on scales 1 (Hs), 2 (D), and 3 (Hy) of the MMPI, using the cut-off criterion of T > or = 70. Malingering was determined by analysis of the dissimulation index from the MMPI (F-K > +9). Significant differences were found for somatization; Hispanics were more likely to somatize. Minimal differences were found between Hispanic and Caucasian subjects on the malingering scale.

Adolescent↗
PubMed1992

Social support of mothers of children with mental retardation.

Utilization of social support and perceptions of family stress of 80 mothers with a child who had mental retardation were examined. Measures of family stress and social support were administered to subjects with a child in one of three normative transition periods. There were no significant differences in family stress scores across the groups. Analysis of variance procedures revealed significant differences in the utilization of intimate support across the age groups. Implications for further research in this area were discussed.

Adaptation, Psychological↗
PubMed1991

The role of selenium in the secretion of very-low-density lipoprotein in the isolated perfused rat liver.

A recirculating liver perfusion system was used to study the effects of dietary selenium (Se) on the hepatic secretion of very-low-density lipoprotein (VLDL). The perfusate from livers of rats fed on a Se-deficient diet incorporated about 50% more [1-14C]oleic acid into triacylglycerol (TG) and cholesteryl esters (ChoEs) than did the perfusate from livers of rats fed on a Se-supplemented diet. Similarly, livers from rats fed the Se-deficient diet secreted more VLDL and incorporated about 60% more [1-14C]oleic acid into VLDL TG and ChoEs than did livers from rats fed the Se-supplemented diet. The liver perfusate from rats in the Se-deficient group also showed significantly decreased fatty acid oxidation. We conclude that Se is a potent modulator of lipoprotein metabolism. A primary action of Se deficiency appears to be a decrease in fatty acid oxidation and a stimulation of fatty acid esterification, leading to increased VLDL TG and ChoEs formation and secretion.

Animals↗
PubMed1990

A scanning electron microscopic study of the effect of air polishing on the enamel-sealant surface.

The purpose of this study was to evaluate the enamel-sealant interface following the use of standard sealant placement techniques and an air-polishing system. Twenty-five caries-free premolars were extracted and stored in distilled water for 2 days. Five teeth were randomly assigned to each of five treatment groups. The occlusal surface was (1) air polished for 20 seconds, (2) cleaned with pumice for 20 seconds, or (3) not cleaned. Following treatment, 35% orthophosphoric acid was applied for 60 seconds. In two control groups, the acid-etching procedure was eliminated, and one group (4) was air polished for 20 seconds, while the other group (5) was not cleaned. Tinted self-curing sealant was applied to the entire occlusal surface of each tooth. Following the treatment, scanning electron photomicrographs were taken at X 1000 magnification. To evaluate the enamel-resin interface, the number of resin tags were counted by one precalibrated rater. A statistically significant difference was found among the treatment groups and the control groups. Air polishing combined with acid etching resulted in an improved surface for resin wetting as determined by the number of resin tags formed; however, the differences among the treatment groups were not large enough to be statistically significant.

Acid Etching, Dental↗
PubMed1989

The role of antioxidant nutrients in preventing hyperbaric oxygen damage to the retina.

Vitamin E and selenium play essential roles in preventing in vivo lipid peroxidation and free radical damage. Hyperbaric oxygen (HBO) treatment adversely affected the electroretinograms (ERGs) of rats fed a diet deficient in both vitamin E and selenium (the basal or B diet) or a diet deficient in vitamin E alone (B + Se diet). After 4 weeks of HBO treatment (3.0 ATA or 100% oxygen, 1.5 hours per day, 5 day/week) rats fed the B diet deficient in vitamin E and selenium for 6 weeks showed decreased (p less than 0.05) a-wave amplitudes, 85 +/- 9 microvolts (microV), n = 11, compared with a-waves recorded (150 +/- 10 microV, n = 21) for age matched rats fed an identical diet for 6 weeks but not treated with HBO. After 15 weeks of HBO treatment, rats fed the B + Se diet deficient in vitamin E alone showed decreased (p less than 0.01) a-wave (61 +/- 9 microV, n = 4) and b-wave (253 +/- 23 microV, n = 4) amplitudes compared with a-wave (115 +/- 7 microV, n = 4) and b-wave amplitudes (450 +/- 35 microV, n = 4) for age matched rats fed the same diet but not treated with HBO. Decreased a- or b-wave amplitudes provide evidence of retinal damage. Rats fed a diet supplemented with vitamin E and selenium or vitamin E alone showed no decreases in either a- or b-wave amplitudes after 15 weeks of HBO treatment.

Animals↗
PubMed1989

Measurement characteristics of a short form of the questionnaire on resources and stress.

The psychometric integrity of a short form of a measure of ecological stress was evaluated based on data provided by both fathers and mothers representing intact families, half of which included children with handicaps and half of which did not. Alpha reliability, factor structure, and construct validity analyses generally supported the conclusion that the short form of the Questionnaire on Resources and Stress is reasonably reliable and valid.

Adult↗
PubMed1989

Relationship between test performance in ocular therapeutics and year of graduation.

Practitioner performance on a national, standardized examination in ocular therapeutics was analyzed. The majority of the practitioners were from one state and had graduated from the same college of optometry. The homogeneity of their background fostered an analysis of the relationship between year of graduation and test performance. The data indicated that less recent graduates did not perform as well as more recent graduates, but that the best performance was attained by practitioners with considerable clinical experience.

Education, Medical, Continuing↗
PubMed1988

Quality assurance review: improving diagnostic accuracy of percutaneous needle biopsy.

Adequate pathologic slide preparation of percutaneous fine-needle biopsy (PFNB) specimens is necessary to maximize sensitivity and yield a tissue diagnosis. We present a quality control review of our biopsy technique and results in 71 aspiration biopsies done in 59 patients. Immediate cytology slide preparation in the radiology suite enabled us to increase our diagnostic yield from 53% to 84%, and allowed us to preserve PFNB, rather than open biopsy, as the primary diagnostic modality. We recommend regular review of biopsy techniques to confirm adequate diagnostic yields of these procedures.

Biopsy, Needle↗
PubMed1987

Pleural aspergillosis diagnosed by computerized tomography.

As shown by the case we have reported, patients with a chronic pneumothorax and nodular, thickened pleura may have pleural aspergillosis. We recommend that when such patients have CT of the chest, the examiner use the alternate dependent position to look for mobile pleural debris.

Aspergillosis↗