Search PubMed⌕ Search

Biomedical subjects

F Schwarz

Publications and source records attributed to F Schwarz.

At least 127 records · Page 7Linked to original sources
PubMed1983

Metabolic responses in grossly obese subjects treated with a very-low-calorie diet with and without triiodothyronine treatment.

Metabolic responses during a very-low-calorie diet, composed of 50 per cent glucose and 50 per cent protein, were studied in 18 grossly obese subjects (relative weights 131-205 per cent) for 28 d. During the last 14 d (period 2) eight subjects (Gp B) served as controls, while the other ten subjects (Gp A) in the low T3 state were treated with triiodothyronine supplementation (50 micrograms, 3 times daily). During the first 14 d (period 1) a low T3-high rT3 state developed; there was an inverse relationship between the absolute fall of the plasma T3 concentrations and the cumulative negative nitrogen balance as well as the beta-hydroxybutyrate (BOHB) acid concentrations during the semi-starvation period, pointing to a protein and fuel sparing effect of the low T3 state. Weight loss in the semi-starvation period was equal in both groups; during T3 treatment the rate of weight loss was statistically significant (Gp A 6.1 +/- 0.3 kg vs Gp B 4.2 +/- 0.2 kg, P less than 0.001). In the control group there was a sustained nitrogen balance after three weeks; in Gp A the nitrogen losses increased markedly during T3 treatment. Compared to the control group, on average a further 45.4 g extra nitrogen were lost, equivalent to 1.4 kg fat free tissue. Thus, 74 per cent of the extra weight loss in the T3 treated group could be accounted for by loss of fat free tissue. During the T3 treatment period no detectable changes occurred regarding plasma triglycerides and plasma free fatty acids (FFA) concentrations; the plasma BOHB acid concentrations decreased significantly as compared to the control group. Plasma glucose concentrations and the immunoreactive insulin (IRI)/glucose ratio increased in Gp A in the T3 treatment period, reflecting a state of insulin resistance with regard to glucose utilization. Our results warrant the conclusion that there appears to be no place for T3 as an adjunct to dieting, as it enhances mostly body protein loss and only to a small extent loss of body fat.

3-Hydroxybutyric Acid↗
PubMed1983

The effect of a low-calorie diet alone and in combination with triiodothyronine therapy on weight loss and hypophyseal thyroid function in obesity.

The effect of a low-calorie diet (200 kcal) composed of about 50 per cent glucose and 50 per cent protein on body weight, thyroid hormone levels and pituitary thyrotrophin response was studied in 18 grossly obese subjects (relative weight 131-205 per cent) for 28 d; during the last 14 d eight subjects (Gp B) served as controls, while in the other ten subjects (Gp A) the low T3-high rT3 state was treated by T3 supplementation (150 micrograms daily). During the first 14 d (period 1) weight loss (corrected for the sodium diuresis) appeared to be constant and to be equal for both groups. The thyroid hormone concentration and the basal and TRH stimulated TSH concentrations were similar to the results from previous total starvation studies. Despite marked changes in serum T3 levels a normal pituitary TSH response was maintained and no delayed response of TSH to TRH occurred. During T3 supplementation the serum T3 levels increased to high values, the rT3 concentration declined to below initial values, the T4 and TSH concentrations were depressed and the response of the TSH concentration to TRH disappeared; apparently these 'high normal' levels of serum T3 must be considered inappropriate for this condition of severe calorie restriction. In the controls the serum T3 levels remained constant after the end of the first period; the serum rT3 concentration declined from day 14 to day 28, but remained above the initial values. The serum T4 concentration remained almost constant during the whole study; basal and TRH stimulated TSH concentrations did not change during the whole study. During period 2 weight loss diminished in the control group, but remained constant in Gp A (T3 supplemented); the correlation between the weight loss and the increase of the serum T3 concentration during triiodothyronine supplementation was significantly negative (r = -0.64; P less than 0.05). The well-being of the subjects did not change during T3 administration and no signs of hyperthyroidism developed. One could speculate this reflects a decrease in number or sensitivity of intracellular receptor sites. It is concluded that at the peripheral level no complete resistance develops against T3 administration; in the low T3 state the hypothalamic-pituitary axis reacts as if euthyroidism exists.

Adult↗
PubMed1983

The effect of modified fasting on blood pressure and sympathetic activity: a correlation?

The effect of a low calorie diet (200 kcal/0.8 MJ) composed of 50 per cent glucose and 50 per cent protein was studied on blood pressure and sympathetic activity in eight normotensive obese subjects. The study lasted 21 days; during the first seven days (period I) a weight maintaining diet was given; this was followed by 14 d (period II) of modified fasting (200 kcal/0.8 MJ). Sodium and potassium intakes of 20 and 80 mmol per d respectively were maintained constant throughout the study. In period I blood pressure decreased slightly until day 5; this occurred concomitantly with a marked natriuresis. Thereafter blood pressure and sodium excretion remained stable. No significant change was observed in the urinary excretion of total catecholamines, noradrenaline and 4-hydroxy-3-methoxy mandelic acid. From the start of period II blood pressure decreased markedly, together with a significant decrease in the urinary excretion of the catecholamines and 4-hydroxy-3-methoxy mandelic acid. Both blood pressure and urinary excretion of catecholamines and 4-hydroxy-3-methoxy mandelic acid stabilized after day 7 of period II. These changes preceded the maximal sodium diuresis of severe calorie restriction. The results suggest a primary role for the sympathetic system in the hypotensive effect of short term calorie deprivation although some influence of natriuresis cannot be excluded.

Adolescent↗
PubMed1983

[Prognostic value of preoperatively determined end-systolic left ventricular diameter in patients with chronic aortic insufficiency--an echocardiographic study].

Serial echocardiographic studies of Henry et al. (Circulation 61, 471 [1980]) in patients with chronic aortic regurgigation (AR) indicate that preoperative left ventricular end-systolic dimension (ESD) greater than 55 mm and fractional shortening (FS) less than 25% may identify patients with reduced postoperative survival. We retrospectively analyzed the onedimensional echocardiograms of 33 patients with AR without coronary artery disease who underwent operation from 1977 to 1981. Twenty-three patients with ESD less than or equal to 55 mm (group A, mean age 48 +/- 10 years) were followed 36 +/- 14 months postoperatively, ten patients with ESD greater than 55 mm (group B, eight patients with FS less than 25%; mean age 48 +/- 12 years) 40 +/- 10 months. In both groups there were no perioperative or late deaths. In group A the average preoperative NYHA functional class decreased from 2.6 to 1.4 postoperatively, in group B from 3.0 to 1.5 (A vs. B: NS). Preoperative FS was 35 +/- 8% in group A and 22 +/- 3% in group B, preoperative ESD 44 +/- 5 mm in group A and 62 +/- 7 in group B. Three years after operation, end-diastolic dimension was 54 +/- 8 mm compared with 68 +/- 5 mm preoperatively in group A (p less than 0.001) and 61 +/- 11 mm compared to 79 +/- 8 mm preoperatively in group B (p less than 0.001). According to these data, a significant postoperative decrease of end-diastolic dimension can be expected in most patients with AR and ESD greater than 55 mm. The long-term prognosis of this subgroup is not so impaired as to recommend aortic valve replacement to asymptomatic patients a priori.

Aortic Valve Insufficiency↗
PubMed1982

[Reactivity of the respiratory tract in healthy humans and with beta-adrenergic blockade].

Airway resistance, FEV 1.0 and lung volumes were measured in 11 normal subjects before and after voluntary hyperventilation and after inhalation of salbutamol and hyperventilation. The measurements were repeated the following day two hours after taking 40 mg propranolol. Under propranolol there is only a minimal increase in inspiratory and expiratory resistance and no change in bronchoconstriction induced by hyperventilation, but the spasmolytic effect of salbutamol is reduced. Blockade of beta-receptors is without influence on airway irritability in subjects without bronchial asthma or chronic asthmatic bronchitis. Blockade of beta-receptors can however reduce the effect of beta-2-receptor stimulants.

Adult↗
PubMed1982

Influence of estradiol on the total uptake and incorporation of thymidine in human breast cancer (MCF-7) in long-term cell culture. Comparison of autoradiographic and biochemical methods.

The total uptake and incorporation into DNA of 3H-thymidine in MCF-7 cells is stimulated by estradiol after an incubation period of 24 h. Prolonged incubations show a decreased rate of both uptake and incorporation of 3H-thymidine, but the labeling index remains elevated up to 48 h. It appears that this is the only exception to the observed good relationship between labeling index and total uptake of 3H-thymidine. This correlation may be of use in comparing autoradiographic and biochemical data on DNA synthesis in the case of culturing both primary mammary tumors and mammary cancer cell lines.

Autoradiography↗
PubMed1982

Coronary collateral vessels: their significance for left ventricular histologic structure.

Whether coronary collateral vessels protect the left ventricular myocardium is unknown. Light microscopic morphometry was carried out on myocardial tissue samples from 56 surgically treated patients with coronary artery disease. Transmural biopsy of the myocardium perfused by the left anterior descending coronary artery was obtained during open heart surgery. In initial reproducibility studies of biopsy samples of 17 patients a sampling error for evaluation of myocardium was defined and differences in transmural fibrosis exceeding +/- 6.2 percent were considered biologically significant. Stenosis of the left anterior descending artery was determined from preoperative angiography. Group A (control group) comprised patients with less than 75 percent area reduction of the left anterior descending coronary artery (mean +/- standard deviation 65 +/- 10 percent). Patients in group B (more than 95 percent area reduction [mean 99 +/- 2 percent] without collateral supply on arteriography) were compared with patients in group C (identical stenosis [mean 99 +/- 2 percent] but with collateral supply). Fibrosis averaged 17 percent in group A, 68 percent in group B (p less than 0.001 versus group A) and 29 percent in group C (p greater than 0.05 versus group A, p less than 0.001 versus group B). Thus, in severe coronary stenosis myocardium supplied by collateral vessels shows less fibrosis on biopsy sample than does myocardium without collateral supply.

Adult↗
PubMed1982

Noninvasive assessment of myocardial contractility in asymptomatic patients with sever aortic regurgitation and normal left ventricular ejection fraction at rest.

In 14 asymptomatic patients with isolated aortic insufficiency the slope k of the end-systolic pressure-volume relation was determined noninvasively with equilibrium radionuclide angiography. The results were compared with changes in left ventricular ejection fraction during maximal physical stress. Nine normal volunteers served as a control group. Patients with aortic insufficiency did not differ significantly from the control group with respect to left ventricular ejection fraction at rest (aortic insufficiency 62 + 8 percent, control 65 +/- 6; probability [p] = not significant [NS]), physical work capacity (aortic insufficiency 113 +/- 32 watts, control 117 +/- 25; p = NS) or age (aortic insufficiency 40 +/- 10 years, control 47 +/- 7; p = NS). The slope (k) of the end-systolic pressure-volume relation was found to be significantly lower in the group with aortic insufficiency (3.1 +/- 1.1) than in the control group (4.1 +/- 0.5; p less than 0.05). Patients with aortic insufficiency could be classified into two subgroups with respect to the slope k. In subgroup A (n = 7) the slope fell within the normal range (4.0 +/- 0.6) as defined by the control group, and the left ventricular exercise reserve was normal (6 percent +/- 1). In subgroup B (n = 7) the slope was significantly lower (2.2 +/- 0.6, p less than 0.01), indicating depressed myocardial contractility, and all patients experienced left ventricular dysfunction during exercise (left ventricular exercise reserve -5 +/- 5 percent). Thus, noninvasive determination of the end-systolic pressure-volume relation identified two subsets of asymptomatic patients with aortic insufficiency, one with impaired myocardial contractility and normal left ventricular exercise reserve and a second group with depressed myocardial contractility and left ventricular dysfunction during exercise. Therefore, an abnormal baseline contractile state in asymptomatic patients with aortic insufficiency may be uncovered by noninvasive determination of the end-systolic pressure-volume relation or by assessing the left ventricular exercise reserve. Serial studies in a larger group of patients undergoing surgical correction of the valve lesion are indicated to determine whether this information will be helpful in evaluating when to operate on asymptomatic patients with aortic insufficiency.

Adult↗
PubMed1982

Intracoronary thrombolysis in acute myocardial infarction: duration of ischemia as a major determinant of late results after recanalization.

To define the effect of duration of myocardial ischemia on the late results after successful thrombolysis in patients with acute transmural myocardial infarction, data on 39 patients treated with intracoronary infusion of streptokinase were analyzed. Patients with successful recanalization of infarct vessel and a time lag between onset of symptoms and reperfusion less than 4 hours were assembled in group A1 (n = 15), and patients with successful recanalization but a time lag of more than 4 hours (n = 17) in group A2. Group B consisted of 7 patients with unsuccessful thrombolysis. Coronary anatomy, left ventricular volume, ejection fraction, and regional ejection fraction of infarct area were determined before and 4 weeks after thrombolysis with cineangiography. Serum creatine kinase activity was serially measured. Before intervention, the groups were comparable with regard to age, Killip class, localization of infarction, incidence of previous infarction, Gensini score of coronary anatomy, left ventricular volume, ejection fraction, regional ejection fraction of infarct area, and serum creatine kinase activity. Four weeks after the intervention, patients in group A1 had a higher ejection fraction (59%) and regional ejection fraction of infarct area (39%) than patients in group A2 (ejection fraction: 49%, p less than 0.05; regional ejection fraction: 26%, p less than 0.05) and group B (ejection fraction: 44%, p less than 0.05; regional ejection fraction: 25%, p = 0.05). Peak serum creatine kinase activity measured during the acute illness was lower in group A1 (764 U/liter) than in group A2 (1,580 U/liter, p less than 0.05) and group B (2,106 U/liter, p less than 0.05). Thus, contraction of infarct area was improved and enzymatic estimate of infarct size was reduced after early as compared with late reperfusion in patients with acute myocardial infarction.

Aged↗
PubMed1982

The effects of global ischemia and reperfusion on human myocardium: quantitative evaluation by electron microscopic morphometry.

During open-heart operation, myocardial biopsies were taken from 31 patients undergoing aortic valve replacement during total cardiopulmonary bypass. The first needle biopsy was taken before induction of cardiac arrest (Kirsch cardioplegia), the second at the end of global ischemia, and the third during the reperfusion period. Teh tissue was investigated by electron microscopy, in both a qualitative and a quantitative manner (morphometry). Ultrastructural morphometry revealed cellular and especially mitochondrial swelling that occurred during the reperfusion phase, but not after ischemia alone. On the basis of morphological measurements, this study shows the occurrence of postischemic cellular and mitochondrial edema that possibly might be avoided by the use of improved techniques of myocardial protection during operation.

Aortic Valve↗