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Biomedical subjects

G D Brown

Publications and source records attributed to G D Brown.

At least 91 records · Page 5Linked to original sources
PubMed1988

Regulation of H-2 class I gene expression in virally transformed and infected cells.

Early studies of the resistance and susceptibility of mouse strains to radiation-induced leukemia virus have demonstrated the important role of altered histocompatibility (H-2) antigen expression in the effectiveness of the immune response of the host to virus-infected and transformed cells. Changes in H-2 gene expression have now been correlated with disease resistance in a variety of viral systems. The experiments discussed indicate that viruses may directly or indirectly affect H-2 antigen expression at various levels of gene expression. These investigations generate a framework for approaching a molecular understanding of viral-induced changes in H-2 gene expression.

Animals↗
PubMed1986

Changing health care environments--implications for physical therapy research, education, and practice. A special communication.

This article explores changes in the organization and management of the health care system and their impact on physical therapy services. It discusses why and how the demand for physical therapy services is changing and how the practice of physical therapy is being altered. The impact of change on physical therapists is presented in terms of such effects as stress, burnout, absenteeism, and job turnover. The article develops approaches that physical therapists, individually and collectively, can pursue to position themselves more effectively in a changing health care environment. These are opportunities as well as constraints. The theme that is presented is how to adapt to change in a positive and proactive manner.

Cost-Benefit Analysis↗
PubMed1986

Effects of exercise and anabolic steroids on total and lipoprotein cholesterol concentrations in male and female rats.

Forty male and 40 female rats were randomly assigned to 1 of 4 experimental groups. Half of the animals of each gender were exercised by jumping (weighted by a vest with up to 70% body weight) to a height of 16 cm 20 times X d-1 (30 s between jumps) 5 d X wk-1 for 8 wk. Half of the exercised animals and half of the sedentary animals were injected with the anabolic steroid durabolin (0.2 mg in 0.1 ml sesame seed oil) 6 d X wk-1 for the last 3 wk of the 8-wk exercise program. The other animals were injected with 0.1 ml of sesame seed oil (as a placebo) on the same schedule. At the end of the 8-wk program, blood was drawn from the right atria of the anesthetized animals. Plasmas were analyzed for total cholesterol (TC) and high density lipoprotein cholesterol (HDL-C) concentrations. Low density lipoprotein cholesterol (LDL-C) concentration was estimated as the difference between these two parameters (TC - HDL-C). A three-factor analysis of variance (2 X 2 X 2) demonstrated that there was a significant (P less than 0.05) gender effect (males greater than females), but no steroid or exercise main effects for TC. There were significant (P less than 0.05) steroid and exercise main effects for both HDL-C and estimated LDL-C, as well as a significant gender main effect for estimated LDL-C (but not HDL-C).(ABSTRACT TRUNCATED AT 250 WORDS)

Anabolic Agents↗
PubMed1985

Two-stage hormonal control of type IV collagen mRNA levels during differentiation of F9 teratocarcinoma cells.

A cDNA clone related to mouse Type IV collagen has been prepared from F9 teratocarcinoma cells induced to differentiate with retinoic acid and dibutyryl-cAMP. This cDNA clone has been used to investigate the regulation of Type IV collagen mRNA during differentiation. The level of this mRNA is very low in untreated F9 cells, increases substantially after treatment of the cells with retinoic acid, and is further increased by addition of dibutyryl-cAMP. In contrast, dibutyryl-cAMP has no effect on the mRNA level in cells that have not been previously exposed to retinoic acid. These results demonstrate that these two compounds regulate in a sequential manner the steady-state level of Type IV collagen mRNA. This cDNA clone should allow a detailed examination of the mechanism of the two-stage regulation of collagen expression by retinoids and cyclic AMP.

Animals↗
PubMed1984

Effects of two "lipid-lowering" diets on plasma lipid levels of patients with peripheral vascular disease.

Fifty subjects with peripheral vascular disease were randomly assigned to either the American Heart Association Hyperlipidemia Diet C (AHA, N = 23) or a higher fiber, low fat diet based on the Pritikin maintenance diet (HFD, N = 27) and studied for a 12-month period. Diet counseling was provided, and the subjects were encouraged to exercise regularly, to decrease their consumption of salt, alcohol, and caffeine, and to restrict cigarettes as much as possible. Dietary intake data showed that energy distribution was approximately 49% and 64% carbohydrate, 20% and 22% protein, and 31% and 14% fat for the AHA and HFD groups, respectively. Cholesterol and dietary fiber intakes averaged 201 mg and 23 gm per day, respectively, for the AHA group and 108 mg and 43 gm per day, respectively, for the HFD group. Generally, both groups showed tendencies toward decreased serum triglycerides, cholesterol, and LDL cholesterol and increased HDL cholesterol. The HFD group achieved a significant decrease in serum cholesterol (at month 12) (p less than .01). The only significant between-group difference was in serum cholesterol at 4 months (p less than .01), with the lower value in the HFD group. There was a consistent negative correlation between dietary fiber and serum cholesterol levels (p less than .01). Average weight loss was 4.1 kg for the AHA group and 6 kg for the HFD group. We concluded that both dietary regimens, combined with exercise, can be of benefit to patients with peripheral vascular disease.

Aged↗
PubMed1984

Application of immunologic assays to the coagulation laboratory.

A number of major advances in the application of immunoassay techniques to the study of hemostasis are presented. Immunoassay methods in general are reviewed, and selected laboratory applications that have been developed for the study of platelet-specific proteins, the coagulation proteins and their protease inhibitors are considered.

Antigens↗
PubMed1983

A simple method for the preparation of extracts from animal cells which catalyze efficient in vitro protein synthesis.

A rapid, simple procedure is described for the preparation of cell-free extracts of both uninfected and virus-infected pig kidney and baby hamster kidney cells which are very active in the in vitro translation of not only endogenous mRNA, but also of exogenous mRNA added to extracts that had been depleted of endogenous mRNA by treatment with micrococcal nuclease. This procedure appears to be adaptable with only minor variations to many eukaryotic cell lines and should greatly facilitate in vitro molecular studies of protein synthesis and gene regulation at the level of translation.

Animals↗
PubMed1983

The white pock mutants of rabbit poxvirus: V. In vitro translation of early host range mutant mRNA.

The abortive infections of pig kidney (PK) cells by both RP mu hr23 and RP mu hr31, two early (DNA minus) white pock (mu) host range (hr) mutants of rabbit poxvirus (RPV), are characterized by the in vivo inhibition of both host and viral protein synthesis by 10 hr postinfection although viral RNA synthesis continues. Further analysis reveals that large quantities of functional viral mRNA can be isolated from PK cells abortively infected with RP mu hr23 and translated in vitro throughout the 10-hr period of infection, even though these mRNAs are almost totally inactive in vivo. The in vitro translation of accumulated mRNA isolated from PK cells abortively infected by RP mu hr31 shows a quite different pattern where the maximum amount of RNA translatable in vitro is found at 6 hr postinfection with lesser amounts at 10 hr postinfection. Although early or prereplicative viral proteins are detected with each mutant both in vivo and after in vitro translation of isolated RNA, few, if any, late proteins are observed under any conditions.

Animals↗
PubMed1983

Endothelial cell activity in experimental hypertension. Effects of hemodynamic factors.

The cause of the increased endothelial cell proliferative activity found in experimental hypertension in the rat is not clear. In this experiment the part played by altered vascular hemodynamics was explored in a model in which part of the aorta was subjected to a high blood pressure and the other not. Hypertension was produced by the application of a tight ligature to the aorta between the levels of the two renal arteries, the mechanism being interference with the blood supply to the more distally placed kidney. Because the aorta is constricted, the segment above the ligature is subjected to high blood pressure and the segment below it to lowered pressure, although both segments are exposed to humoral factors such as renin and angiotensin II. Aortic endothelial cells were labeled with tritiated thymidine and cell replication and cell density studies carried out using en face monolayer preparations of endothelium. It was found that endothelial cell replication was considerably increased at 7 days following induction of hypertension in segments of aorta above the ligature but not in the segment below the ligature. The increased activity was short-lived and had returned to normal levels at 4 weeks. Cell density was increased above the ligature at both 1 and 4 weeks following induction of hypertension. The changes are consistent with the idea that the increased cell replication and consequent increased cell density above the ligature were initiated by the increased stretching of the aortic wall attending the development of hypertension.

Animals↗
PubMed1982

Aortic endothelial cell activity in high renin and normal renin models of hypertension in the rat.

To determine whether renin or angiotensin might have an effect on endothelial cell activity, we studied cell replication and cell density in two models of hypertension in the rat. The first was a model in which the plasma renin activity was high during the three time periods studied (1, 2, and 4 weeks after renal artery constriction) and the second, a model with elevated plasma renin activity only during the initial period (1 weeks). Aortic endothelial cells were labeled with tritiated thymidine period to killing, and en face endothelial cell monolayers were prepared. The ratio of labeled cells to total cells (thymidine index) and the ratio of total number of cells to number of fields observed (cell density) were calculated for the whole aorta, segments of the aorta, and zones within the segments. In both hypertensive models, an elevation of the thymidine index (indicative of increased endothelial cell replication) was observed at 1 week but not at subsequent times when the levels had returned to those of the controls. Cell density was increased at all time periods studied and like the thymidine index showed no significant differences between the two hypertensive models. Although renin or angiotensin (or other humoral factors) could have been responsible for the increased thymidine index after 1 weeks, it is considered that hypertension itself it a more likely cause, taking into account the decreased indices at later time periods when one model has high renin levels and the other does not. The increased cell density at all time periods studied in both models is regarded as an adaptive reaction to the increased blood pressure.

Animals↗
PubMed1980

A comparison of contract-managed and traditionally managed nonprofit hospitals.

During the past five years, contract management of nonprofit hospitals by for-profit corporations has increased markedly. However, while a number of studies have been conducted on investor-owned hospitals and proprietary hospital systems, contract-managed hospitals have not been evaluated systematically. This paper reports a pilot study which compares a sample of 32 nonprofit hospitals under management contracts with matched hospitals uneder traditional in-house management. Although few major differences were found between the study hospitals, the findings indicate that contract-managed hospitals tend to offer a somewhat broader range of services, especially in the outpatient area, younger, more highly educated administrators, and show lower cost per patient stay largely due to somewhat lower employee-to-bed and payroll-to-total expense ratios and shorter lengths of stay.

Contract Services↗
PubMed1979

A precision study of a photo-optical factor VIII assay technic.

Various methods of factor VIII analysis with a wide range of accuracies as confirmed by calculated coefficients of variation have been devised. The authors report a technic of factor VIII assay using a photo-optical clot-detection instrument with commercially available sources of factor VIII-deficient plasma and lyophilized normal control plasma, and compare its accuracy, ease of performance and reliability with those of existing methods. The accuracy of the technic was established by a survey of a normal control group, which revealed a mean value of 100% factor VIII activity, range 55-200%. The coefficients of variation of this unique technic, determined both by clotting time in sec (1.4%) and by the derived percentage activity (7.0%), reflect the greater reproducibility and reliability of the assay as compared with previously reported methods. We feel that this method of factor VIII assay should be utilized for specific diagnostic information regarding patients who have factor VIII disorders.

Blood Coagulation Tests↗
PubMed1979

Fatal pulmonary embolism in an adolescent with chickenpox.

A fatal case of pulmonary emboli associated with varicella in an adolescent is reported. Review of the literature revealed confusion between pulmonary infarction and embolization, the latter having been documented with varicella only in adults before this report. Embolic phenomena should be considered in the differential diagnosis of pulmonary symptoms associated with varicella, since their recognition and treatment offers important supportive measures in the care of the frequently critically ill patients.

Adolescent↗