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Biomedical subjects

R Friis

Publications and source records attributed to R Friis.

At least 37 records · Page 2Linked to original sources
PubMed1988

Oncogenes modulate cellular gene expression and repress glucocorticoid regulated gene transcription.

The v-mos oncogene was subjected to the transcriptional control of the MMTV LTR and introduced by transfection into NIH 3T3 cells. The LTR v-mos gene was induced by the addition of glucocorticoid hormone to the growth medium of cells synchronized by culturing in 1.5% FCS for 36 h. The effects of p37 v-mos expression were monitored. The endogenous c-myc gene is induced as a consequence of p37 v-mos expression in a transient fashion, reaching a maximum of expression after 8 h. Induction of the c-myc gene was observed at the level of its transcriptional rate and at the level of mRNA concentration. Ornithine decarboxylase (ODC) mRNA was induced constitutively and high levels were found 8 and 25 h after v-mos induction. H4 histone mRNA is elevated at 25 h after hormone addition at a time when the mitogenic stimulus of v-mos causes DNA synthesis. The expression of actin mRNA is not affected by the v-mos oncogene. We have previously described a modulation of glucocorticoid dependent gene expression by oncogenes. In an extension of these observations the consequences of expression of the v-mos and the v-ras oncogenes were also studied in retrovirally infected NIH 3T3 cells. MMTV LTR constructs transfected into the infected cells could only be transiently induced by glucocorticoid hormone. The presence of the p37 v-mos and the p21 v-ras oncoproteins causes a repression of glucocorticoid hormone dependent gene transcription.

Actins↗
PubMed1988

Maximal exercise testing and gas exchange in patients with chronic atrial fibrillation.

To evaluate the response of patients with chronic atrial fibrillation to exercise, 50 men (mean age 65 +/- 8 years) with atrial fibrillation underwent a maximal exercise test using respiratory gas exchange techniques. Patients were classified by the presence (n = 29) or absence ("lone atrial fibrillation," n = 21) of underlying heart disease. Responses were evaluated at a standard submaximal work load (3.0 mph, [4.8 km/h] 0% grade), at the gas exchange anaerobic threshold and at maximal exercise. For all 50 patients, the mean maximal oxygen uptake was 20.6 ml/kg per min, which approximates 85% of the aerobic capacity predicted for age-matched normal individuals. Patients with lone atrial fibrillation demonstrated normal exercise capacity in contrast to patients with atrial fibrillation and known heart disease (22.7 +/- 5 versus 19.1 +/- 5.0 ml/kg per min, p less than 0.05). The mean maximal heart rate (176 +/- 30 beats/min) was approximately 20 beats/min higher than that expected for age, was extremely variable and accounted for only 8% of the variance in maximal oxygen uptake. Maximal heart rate in subjects with lone atrial fibrillation was higher than that of subjects with atrial fibrillation and known heart disease (189 +/- 32 versus 166 +/- 24 beats/min, p less than 0.01). Stepwise regression analysis revealed that maximal systolic blood pressure accounted for 19% of the variance in maximal oxygen uptake (VO2 max), suggesting that systolic function is an important determinant of exercise performance in atrial fibrillation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

Exercise-induced hypotension in a male population. Criteria, causes, and prognosis.

The objective of this study was to demonstrate the causes, optimal definition, and predictive value of exercise-induced hypotension occurring during treadmill testing. This study included all patients referred for clinical reasons to the Long Beach Veterans Administration Medical Center treadmill laboratory and then followed for a 2-year period for cardiac events. The population consisted of 2,036 patients who underwent testing from April 4, 1984, to May 7, 1987, 131 of whom exhibited exercise-induced hypotension (6.4%). We found that exercise-induced hypotension is usually related to myocardial ischemia or myocardial infarction, is best defined as a drop in systolic blood pressure during exercise below the standing preexercise value, and indicates a significantly increased risk for cardiac events (3.2-fold, p less than 0.005). This increased risk was not found in those having no previous myocardial infarction or no signs or symptoms of ischemia during the exercise test, and the increased risk was also not found in those undergoing a treadmill test within 3 weeks after a myocardial infarction. Exercise-induced hypotension appeared to be reversed by revascularization procedures, but confirmation of a beneficial effect on survival requires a randomized trial. The clinical importance of this study is that we have demonstrated that a drop in systolic blood pressure below standing preexercise values during treadmill testing indicates an increased risk for cardiac events except in certain subsets of patients.

Adult↗
PubMed1988

Effect of rapid weight loss with supplemented fasting on serum electrolytes, lipids, and blood pressure.

The effect of rapid weight reduction with supplemented fasting was studied in a group of 46 individuals with moderate to severe obesity. The preparation used contained a mixture of protein, carbohydrate, and essential fatty acids providing 420 kcal daily. It was supplemented with a complement of electrolytes, minerals, and vitamins.Serum concentrations of electrolytes, urea nitrogen, creatinine, uric acid, glucose, cholesterol, and triglycerides were measured prior to the onset of the study and at two-week intervals for a six-week study period. In addition, blood pressure, heart rate, and body weight were recorded regularly. A mild and transient fall in serum bicarbonate concentration and a rise in uric acid level was observed.In contrast to other regimens, hypokalemia was not observed in the present study. In fact, serum K+ concentration rose slightly while serum Na+ concentration remained virtually unchanged. There was a transient rise in serum creatinine concentration followed by a fall to values below the baseline. Serum glucose, cholesterol and triglyceride levels, blood pressure, and heart rate decreased significantly. Body weight fell from 232.7 ± 58 lb at the onset of the study to 176.4 ± 47.9 lb at the conclusion of the study.The protocol was well tolerated and the side effects were mild and infrequent. In conclusion, the present protocol provides a safe and effective means for rapid weight reduction in individuals with moderate to marked obesity without producing severe electrolyte disturbances seen with other modalities.

Adult↗
PubMed1987

Efficacy of the routine admission urinalysis.

The clinical efficacy of routine admission urinalyses was evaluated in 301 patients admitted to the internal medicine wards of a university teaching hospital. Using a consensus analysis approach, three Department of Medicine faculty members reviewed the patients' charts to determine which tests were performed routinely and which test results led to diagnostic or therapeutic management changes. Of the 243 urinalyses performed, 123 (51 percent) were ordered routinely for patients without recognizable medical indications. Results of the routine urinalyses were abnormal in 42 (34 percent) of the patients and led to additional laboratory testing in 20 (16 percent) of the cases. However, the test results led to therapeutic changes in only three (2.4 percent) of the patients, and in two of these patients, the treatment instituted probably was unnecessary. It is concluded that the impact of routine admission urinalysis on patient care is very small and that there is little justification for ordering this test for all patients admitted to the hospital.

Adult↗
PubMed1987

Effect of rapid weight loss with supplemented fasting on liver tests.

We monitored serum liver tests in 46 obese persons undergoing rapid weight reduction with a supplemented fasting diet containing a mixture of protein, glucose, essential fatty acids, vitamins, and minerals. Levels of SGOT, SGPT, alkaline phosphatase, lactic dehydrogenase (LDH) and serum concentrations of bilirubin, total protein, and albumin were within normal limits at the onset of the study. SGOT, SGPT, LDH, alkaline phosphatase, and serum total bilirubin rose mildly but significantly 2 weeks after the institution of the supplemented fasting program. Thereafter, the values began to decline, approaching baseline levels within 4-6 weeks despite the continued dietary restrictions. We conclude that rapid weight reduction using a supplemented fasting regimen can lead to a mild hepatic test abnormality. The resultant liver test abnormalities are transient and reversible and may not require extensive diagnostic investigations.

Adult↗
PubMed1987

Influence of exercise training on spatial R-wave amplitude in patients with coronary artery disease.

To evaluate the influence of an exercise program on spatial and left precordial R-wave amplitude among patients with coronary artery disease, computerized electrocardiogram (ECG) data were acquired during maximal treadmill testing before and after 1 yr in 89 patients randomized to either exercise (n = 40) or control (n = 49) groups. Spatial and lateral R-wave amplitudes were derived from the orthogonal Frank (XYZ) lead system. The exercise group significantly increased maximal O2 consumption (0.17 l/min), whereas controls decreased significantly (0.12 l/min, P less than 0.01 between groups). No significant changes in electrocardiographic R-wave voltage measurements occurred within or between groups during the year. It is concluded that exercise training does not result in increases in R-wave voltage in patients with coronary artery disease.

Angina Pectoris↗
PubMed1987

Perceived exertion and gas exchange after calcium and beta-blockade in atrial fibrillation.

Nine male patients (mean age 65 yr) with chronic atrial fibrillation underwent maximal exercise testing during placebo, beta-adrenergic (celiprolol, 600 mg), or calcium (diltiazem, 30 or 60 mg four times daily) channel blockade. The results were analyzed to determine which factors most closely related to ratings of perceived exertion (RPE) during exercise. Heart rate (HR), blood pressure (BP), oxygen uptake (VO2), minute ventilation (VE), and carbon dioxide production (VCO2) were evaluated at rest, 3.0 mph/0% grade, the gas exchange anaerobic threshold (ATge), 80% of placebo maximal O2 uptake, and maximal exercise. Both beta-adrenergic and calcium channel blockade significantly reduced heart rate and systolic blood pressure relative to placebo; these effects were more profound during beta-adrenergic blockade and as exercise progressed. Correlation coefficients and estimates of slope were derived for changes in RPE during exercise vs. changes in HR, VO2, VE, and VCO2 during the three treatments (r = 0.76 to 0.92, P less than 0.001). Although RPE was significantly correlated with HR during placebo and diltiazem therapy (r = 0.45, P less than 0.01), this was not the case during beta-adrenergic blockade (r = 0.31, NS). Slope of the regression lines between RPE and VO2, VE, and VCO2 did not differ between the three treatments. Slope of the regression lines between RPE and HR differed only during calcium channel blockade. Because the presence of atrial fibrillation and beta-adrenergic blockade altered the associations between RPE, VO2, and HR, these results suggest that VE is more closely related to RPE than the other parameters.

Adrenergic beta-Antagonists↗
PubMed1986

Diabetes, depression and employment status.

The relationship among diabetes, depression and employment status was assessed. It was hypothesized that: unemployment would be associated with diabetes; and employability problems would be associated with higher depression levels among diabetic persons than among non-diabetic persons. A case-control design was employed in which the cases (n = 56) were currently active diabetic patients and the controls (n = 56) were non-diabetic patients. Subjects were selected from a computerized data base at a primary care clinic located in Orange County, California, U.S.A. Depression was measured by the CES-D scale. The results were as follows: diabetes was associated with both depression and unemployment; being employed was the most significant predictor of depressive symptomatology followed by being diabetic; and education, type of diabetes, blood sugar level, medication type were not significant predictors of depressive symptomatology in a stepwise multiple regression analysis. Problems of employment among diabetic persons may warrant special employment and counseling programs.

California↗
PubMed1986

Expression of anti-sense mRNA in H-ras transfected NIH/3T3 cells does not suppress the transformed phenotype.

We have attempted to reverse the transformed phenotype of cells expressing the H-ras oncogene. A plasmid in which the first exon of the H-ras oncogene was coupled to the SV40 early promoter in an anti-sense orientation was constructed. This construct was introduced into a clone of H-ras-transformed NIH/3T3 cells. Simultaneous expression of both the SV40 anti-sense construct and H-ras was observed. Anti-sense RNA was present in a 10-20-fold excess over sense H-ras RNA. Only a small fraction of the cytoplasmic RNA was present in a sense: anti-sense duplexed form. The expression of anti-sense H-ras RNA was not accompanied by a phenotypic reversion of transformed cells. The only phenotypic reversion we observed was accompanied by a loss of transfected H-ras sequences. The loss of transfected H-ras sequences occurs with a high frequency in cells supertransfected with the SV40 anti-sense construct.

Animals↗
PubMed1986

The effect of modified transurethral sphincterotomy on autonomic dysreflexia.

Autonomic dysreflexia continues to be a major problem in spinal cord injury patients. In our report 16 patients with spinal cord lesions above the T6 level and a history of autonomic dysreflexia also had detrusor-sphincter dyssynergia. Of these patients 12 (75 per cent) had evidence of dysreflexia during cystometry. In addition, the dysreflexic response in blood pressure was shown to correlate with the high intravesical and urethral pressures measured during cystometry. Modified transurethral sphincterotomies subsequently were performed on all patients as recommended therapy for detrusor-sphincter dyssynergia. Repeat cystometry revealed significant decreases in intravesical and urethral pressures compared to before sphincterotomy (p less than 0.001) along with an associated significant decrease in blood pressure (p less than 0.01). Other dysreflexic responses also were markedly attenuated. These results suggest an association among detrusor-sphincter dyssynergia, high intravesical and urethral pressures, and autonomic dysreflexia. Our data indicate further that the frequency and magnitude of autonomic dysreflexia can be diminished significantly by modified external sphincterotomy.

Adult↗
PubMed1986

Exercise electrocardiographic variables: a critical appraisal.

To compare four recently proposed methods of analyzing the exercise electrocardiogram with the conventional analysis of ST segment depression, 303 consecutive patients without myocardial infarction who had been referred for coronary arteriography underwent stress electrocardiography and stress thallium imaging. The specificity for the prediction of a greater than 50% coronary obstruction of 0.5, 1.0, 1.5 and 2.0 mm ST segment depression measured in the conventional way was 0.59, 0.73, 0.88 and 0.94, respectively. The specificity of a thallium perfusion defect was 0.79. Sensitivities of the conventional ST depressions, thallium defect, the change in the sum of the R amplitudes and the slope adjusted for heart rate increase were calculated and compared at the cited levels of specificity. R wave changes had a significantly lower sensitivity than did the conventionally analyzed ST depression at each level of specificity. Slope-adjusted ST depression had a slightly higher sensitivity than that of conventional ST depression only at a specificity of 0.73 (0.68 versus 0.65, p = 0.07). R wave-adjusted ST depression was significantly more sensitive than conventional ST depression only at a specificity of 0.94 (0.45 versus 0.36, p = 0.01). Heart rate-adjusted ST depression was more sensitive than conventional ST depression at all of the specificities except 0.59. This pattern of superior accuracy of heart rate-adjusted ST depressions was preserved for the prediction of multivessel coronary disease. Heart rate adjustment is a simpler and more accurate modification of the conventional electrocardiographic analysis than are the other three methods studied.

Adult↗
PubMed1985

Safety of human blood products: inactivation of retroviruses by heat treatment at 60 degrees C.

Acquired immune deficiency syndrome (AIDS) can be transferred to patients by blood transfusions or human blood preparations, such as cryoprecipitates or factor VIII concentrates. Retroviruses have been discussed as infectious AIDS agents and more recently human T-lymphotropic retroviruses designated as HTLV type III and LAV (lymphadenopathy-associated virus) have been isolated from AIDS patients. Whether heat treatment at 60 degrees C (pasteurization) of liquid human plasma protein preparations inactivates retroviruses was therefore investigated. Pasteurization had already been included in the routine manufacturing process of human plasma protein preparations in order to guarantee safety with regard to hepatitis B. Since high titer preparations of human retroviruses were not available, heat inactivation was studied using Rous sarcoma virus added to the various plasma protein preparations tested. This retrovirus which was obtained in preparations of 6.0 log10 FFU/ml was shown to be at least as heat stable as two mammalian retroviruses studied, i.e., feline and simian sarcoma virus. In all of eight different plasma protein preparations tested, Rous sarcoma virus was completely inactivated after a heat treatment lasting no longer than 4 hr. It is thus concluded that pasteurization of liquid plasma protein preparations at 60 degrees C over a period of 10 hr must confer safety to these products with respect to AIDS, provided that the AIDS agents are retroviruses of comparable heat stability as Rous sarcoma virus and the mammalian retroviruses tested.

Acquired Immunodeficiency Syndrome↗
PubMed1982

A new test of peripheral insulin sensitivity in vivo using artificial beta cell.

A new in vivo test of insulin sensitivity is described. It utilizes closed-loop insulin delivery device (GCIIS, Biostator) capable of infusing glucose and insulin according to preselected algorithms. In euglycemic patients, insulin was infused by GCIIS to maintain euglycemia in the face of challenges with gradually increasing doses on intravenously administered glucose. Under the described experimental conditions, the endogenous insulin release was minimized as evidenced by serum C-peptide levels of less than 2 ng/ml, and thus the peripheral disposal of glucose should have depended entirely on the exogenous insulin. The amount of the insulin infused was considered to be a measure of peripheral insulin sensitivity. The test was applied to normal and non diabetic obese individuals, and to diabetics, both insulin dependent and independent. Significant insulin resistance was demonstrated in the obese and diabetic patients. In two obese females, the test was repeated after a prolonged period of starvation, and showed marked increase in insulin sensitivity. In two poorly controlled insulin dependent diabetics, marked increase in insulin sensitivity was also observed, here following a prolonged period of euglycemia (48 hours). It is concluded that the GCIIS controlled insulin sensitivity test is a simple, reliable test of peripheral insulin sensitivity, most convenient for clinical and experimental studies in vivo.

Adult↗
PubMed1982

The structure of the Rous sarcoma virus glycoprotein complex: in vitro phenotypic mixing of rous sarcoma virus.

Gp 85 the major envelope glycoprotein of Rous sarcoma virus can be released from intact by virus treatment with 2-mercaptoethanol. Attempts were made to reassociate released gp 85 to 2-mercaptoethanol treated virus. In order to study the biological activity and to analyse the reaction product with biochemical methods gp 85 from a subgroup different from the recipient virus was used. Successful in vitro phenotypic mixing could be shown. The biochemical analysis, however, revealed that no reassociation of gp 85 and gp 35 could be obtained. The biological activity was due to a strong association of whole gp 85-gp 35 molecules derived from the gp 85 preparation to the recipient virus. These molecules were present as a minor contamination in the gp 85 preparation.

Avian Leukosis Virus↗
PubMed1982

Fusion injection of Rous Sarcoma virus proteins into Rous sarcoma virus-transformed, non-producing hamster cells causes release of infectious virus.

Purified virus proteins from transformation-defective (td) mutants of Rous sarcoma virus PrA or PrB were trapped in human erythrocyte ghosts which, after resealing, were fusion-injected into hamster RBH cells or rat TWERC cells. These cell lines are non-productively transformed by subgroup C Rous sarcoma virus. After fusion injection the hamster RBH cells released transforming subgroup C Rous sarcoma virus. No infectious virus could be rescued from rat TWERC cells. Since previous experiments have shown that fusion injection of the purified Rous sarcoma virus protein p15 into hamster RBH cells caused cleavage of the precursor protein pr76 to form the virus group-specific antigen (gag) but did not induce infectious virus, we conclude that in addition to p15 other virus proteins are required to induce virus rescue in hamster RBH cells.

Animals↗