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Biomedical subjects

G Simon

Publications and source records attributed to G Simon.

At least 235 records · Page 13Linked to original sources
PubMed1983

Increased renal plasma flow in long-term enalapril treatment of hypertension.

The renal effects of long-term antihypertensive treatment with enalapril were evaluated in 34 subjects (age, 53 yr; range, 27 to 65) with mild, uncomplicated hypertension. After receiving placebo for 4 wk, subjects were randomly assigned to groups receiving incremental doses of enalapril (10, 20, or 40 mg/day for 4 wk each) in a single morning dose or two divided doses, or of placebo. One subject who received enalapril developed acute renal failure by the end of the study. There was no evidence of glomerular or tubular damage in the other subjects; as measured by 24-hr urinary protein excretion, urinary activity of N-acetyl-beta-D-glucosaminidase, and uric acid clearance. During treatment with enalapril, renal plasma flow (measured with 131I-iodohippurate sodium) and glomerular filtration rate increased by 12.1% and 6.8%. Changes in renal plasma flow correlated inversely with age and final mean arterial pressure and correlated positively with initial plasma renin activity of subjects. Except for an occasional idiosyncratic adverse reaction, enalapril is a safe and effective antihypertensive drug with the unique ability to increase renal function despite a fall in renal perfusion pressure.

Acute Kidney Injury↗
PubMed1983

Cardiac and hormonal effects of enalapril in hypertension.

Systolic time measurements, echocardiography, and bicycle exercise testing with cardiac output determinations (CO2 rebreathing) were used to evaluate cardiac performance in 16 male hypertensives at the end of a 4-wk placebo period and after 12 wk of treatment with increasing doses (maximum = 40 mg/day) of enalapril maleate (N = 11) and of placebo (N = 5). The effect of exercise on plasma renin activity (PRA) and plasma norepinephrine (NE) concentration was also measured. Mean arterial pressure was reduced by 10 mm Hg or more in all but one subject who received enalapril. In both the enalapril- and placebo-treated subjects, the preejection period/left ventricular ejection time ratio and fractional shortening of the left ventricle at rest and cardiac output and stroke volume during moderate exercise did not change during the study. Enalapril induced a compensatory rise in PRA (N = 10). Compared to plasma NE concentration, 1124 +/- 380 pg/ml (mean +/- SD), during exercise at the end of the initial placebo period, there was attenuation of the rise of plasma NE concentration, 851 +/- 290, at the same load of exercise during enalapril therapy. Unchanged cardiac performance despite effective long-term lowering of blood pressure with enalapril may relate to inhibition of angiotensin II-mediated facilitation of NE release from peripheral nerve endings.

Adult↗
PubMed1983

Echocardiographic evidence for increased cardiac performance during early renal hypertension in dogs.

Cardiac function early (less than 4 weeks) in the course of experimental renal hypertension was investigated. In 11 male mongrel dogs, one kidney was wrapped in silk to produce two-kidney, one-wrapped hypertension. Two weeks later, the contralateral kidney was removed. Five sham-wrapped and then contralaterally-nephrectomized dogs served as controls. M-mode left ventricular (LV) echocardiograms were recorded twice weekly in all dogs for 4 weeks before and for 2 weeks after wrapping (or sham-wrapping) and for 4 weeks after nephrectomy. In the 11 hypertensive dogs, mean arterial pressure (MAP) rose from 127 mm Hg (mean) to 143 two weeks after wrapping (p less than 0.05) and to 185 two weeks after nephrectomy (p less than 0.001). The fractional shortening of the left ventricle (% delta D) of hypertensive dogs was increased (9% maximum, mean, p less than 0.01) for 2 weeks after wrapping and for one week after nephrectomy. Two weeks after wrapping, LV end-systolic wall stress calculated from femoral artery peak systolic pressure, end-systolic dimension and wall thickness was unchanged, suggesting that increased myocardial contractility accounted for the findings. In normotensive control dogs, there were no echocardiographic changes during the study.

Animals↗
PubMed1983

Passive transfer of pressor hyperresponsiveness from renal-hypertensive to normotensive rats.

The role of serum factors in the pathogenesis of pressor hyperresponsiveness in hypertension was investigated by the passive transfer of serum from donor rats with chronic one-kidney, one clip hypertension into syngeneic normotensive recipient rats (0.25 ml iv, bid) for 3 weeks. Rats injected twice daily with the serum of normotensive rats served as controls. In rats injected with the serum of hypertensive rats there was a gradual increase in pressor responses to norepinephrine and angiotensin II and, at the end of the study, increased water content of the aorta and sodium content of the myocardium. In volume-expanded renal hypertension unidentified serum factors contribute to pressor hyperresponsiveness and increased sodium content of cardiovascular tissue.

Angiotensin II↗
PubMed1983

Scintigraphic evaluation of muscle damage following extreme exercise: concise communication.

Total body Tc-99m pyrophosphate scintigraphy was performed on 11 "ultramarathon" runners to assess the ability of nuclear medicine techniques to evaluate skeletal-muscle injury due to exercise. We found increased muscle radionuclide concentration in 90% of the runners. The pattern of muscle uptake correlated with the regions of maximum pain. The detection of exercise-induced rhabdomyolysis appeared to be best when scintigraphy was performed within 48 hr after the race, and to be almost undetectable after about a week. It was possible to differentiate muscle injury from joint and osseous abnormalities such as bone infarct or stress fracture. Although 77% of the runners had elevated serum creatine kinase MB activity, cardiac scintigraphy showed no evidence of myocardial injury.

Adult↗
PubMed1983

Effect of adenovirus infection on human peripheral lymphocytes.

The effect of adenovirus infection on human peripheral lymphocytes has been studied in vitro. Virus antigens were found to multiply in the cell cultures but no infective virus was formed. On infecting the lymphocytes after stimulation with phytohaemagglutinin, infective virus was formed though in low titre. Adenovirus infection decreased the E-rosette forming activity and the response to phytohaemagglutinin of the lymphocytes. The immunomodulating drug levamisole failed to influence significantly the effect of the virus. Adenovirus thus causes several changes in the characteristics of peripheral lymphocytes which may lead to a disturbance of the immune function.

Adenoviridae Infections↗
PubMed1983

Propranolol-induced hyperthyroxinemia.

A patient on a regimen of 400 mg/day of propranolol hydrochloride was observed to have elevated thyroxine (T4) and free T4 levels with a normal thyrotropin response to protirelin. This led us to study the prevalence of hyperthyroxinemia in 14 consecutively treated patients with hypertension on daily doses of propranolol of 320 mg or more. Four of 14 patients had elevated serum T4 levels. As a group, the patients on propranolol therapy had higher serum T4 levels, free T4 indices, and triiodothyronine levels than did healthy controls. The use of high-dosage propranolol may be associated with euthyroid hyperthyroxinemia and be a source of diagnostic confusion. All patients receiving therapy with high-dosage propranolol should undergo protirelin testing before one can conclude that their elevated thyroid hormone levels are due to hyperthyroidism.

Humans↗
PubMed1983

[Chronic polyarthritis in cystic fibrosis].

In a 8 year-old girl, presenting with cystic fibrosis and severe respiratory failure, a chronic polyarthritis with skin rashes occurred. Rheumatoid factor was lacking in the serum. Antibiotic treatments of the pulmonary infections resulted repeatedly in an improvement of both articular and cutaneous disorders. Thus, the trigger-action of the microbic infection was considered as the inducer of a "reactive arthritis".

Arthritis, Juvenile↗
PubMed1982

[Anatomical and functional changes in the heart caused by physical stress shown in M-mode echocardiography].

The paper focuses on the determination of echocardiographic standard values for male and female standard persons between the age of 10 and 30 (n = 180), the determination of the physiological extreme variants of competitive athletes (n = 148) and the analysis of the mode of operation of the heart at rest and during physical stress of the trained and untrained heart (n = 45). Body weight and body surface are both equally suited as reference values for the specification of echocardiographic standard values. Echocardiographic index values relative to the body surface (mm/m2) cannot be used as standard values for persons with different body measurements. Under long-term intensive stress of training an adaption of the heart in the sense of an eccentric hypertrophy occurs in the case of endurance athletes, while in the case of strength athletes a cardiac adaption towards a concentric hypertrophy may be noted. During dynamic physical activity (50 and 100 W) hearts of different sizes at the same levels of stress show clear differences with regard to the changes in size resulting from physical stress and with regard to contractility. Related to equal heart rate as an indication for an equal sympathetic impulse, however, the reaction of hearts of different sizes resulting from physical stress is almost identical.

Adolescent↗
PubMed1982

Echocardiographic evidence for early left ventricular hypertrophy in dogs with renal hypertension.

To investigate the rate of development of left ventricular hypertrophy, left ventricular wall thickness was measured with M mode echocardiography in 12 unanesthetized dogs for several weeks before and for 8 weeks after the induction of hypertension. Hypertension was produced by wrapping one kidney in silk an performing contralateral nephrectomy 2 weeks later. Echocardiographic measurements were performed two to three times weekly and were averaged. The intraobserver and interobserver variability of left ventricular posterior wall thickness measurements was, respectively, 3.9 percent (correlation coefficient [r] = 0.96, n = 27) and 5.4 percent (r = 0.93, n = 14). Left ventricular wall thickness during the baseline period was 7.8 +/- 0.2 mm (mean +/- standard deviation) with a coefficient of variation of 2.9 percent. After the wrapping of one kidney in silk, the mean arterial pressure increased by 10 mm Hg during week 1 (difference not significant) and by 12 mm Hg during week 2 (p less than 0.05). After contralateral nephrectomy, mean arterial pressure increased by 46 mm Hg (p less than 0.001) in 1 week and remained near that level for the rest of the study. In contrast, a significant increase in left ventricular wall thickness occurred during week 1 after wrapping (p less than 0.05). A gradual increase in left ventricular wall thickness continued during the entire study. Sequential M mode echocardiography in dogs is a sensitive and reproducible method of detecting small changes in left ventricular wall thickness. The early increase in left ventricular wall thickness in hypertensive dogs with only minimal increase in mean arterial pressure and the dissociation between the rate of development of hypertension and of left ventricular hypertrophy suggest that factors other than the pressure overload also may contribute to the initiation and evolution of cardiac hypertrophy.

Animals↗
PubMed1982

The electrocardiogram in patients with scoliosis.

Electrocardiograms of 802 patients with isolated scoliosis followed and/or operated at Columbia Presbyterian Medical Center were reviewed. There were 586 patients younger than 18 years and 216 patients older than 18 years of age. There were 86 males and 716 females. Eleven patients had associated congenital heart disease. Effects of age, site of scoliosis, side of convexity and severity of curvature on multiple electrocardiographic variables were analysed. Electrocardiographic variables such as heart rate, Q-Tc, P wave amplitude, P-R interval, amplitude of R and S waves in V1 and V6 were similar to data reported in the normal population without scoliosis. The effect of age on these electrocardiographic variables was similar to changes reported in the normal population and were not affected by site of scoliosis or side of curvature. The frontal QRS axis was within normal limits of 94% in patients under 18 years of age with right-sided thoracic scoliosis and in 87% of patients over 18 years. Evidence of right axis deviation (5%) and right ventricular hypertrophy (2%) were present equally in patients younger and older than 18 years of age and 8% of patients over 18 years old. Since in our patient population the degree of scoliosis severity increased with age it is likely that the increasing incidence of left axis deviation found in patients over 18 years of age with scoliosis is related to scoliosis severity and the altered intrathoracic cardiac orientation. Because right axis deviation and right ventricular hypertrophy are noted occasionally in patients with scoliosis and because congenital heart disease and pulmonary disease are more prevalent in this patient population, it is recommended that the presence of right axis deviation and right ventricular hypertrophy on the ECG should lead to a complete cardiopulmonary evaluation and exclusion of possible additional cardiac or pulmonary anomalies.

Adolescent↗
PubMed1982

Suprapubic bladder puncture in a private pediatric practice.

Suprapubic bladder puncture was performed 185 times in 126 girls in a private pediatric practice. Cultures of urine obtained by aspiration confirmed symptoms as indicative of urinary tract infection in 59% of instances and confirmed positive cultures of urine obtained by voiding in 57% of instances. Since suprapubic bladder puncture avoids the problem of contamination, it enables a certainty in diagnosis that voided specimens cannot. The procedure was easily accomplished in the office and was readily accepted by parent and child. No complications were observed.

Adolescent↗