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Biomedical subjects

U Julius

Publications and source records attributed to U Julius.

66 records · Page 4Linked to original sources
PubMed1978

Influence of diet composition on insulin output, carbohydrate tolerance and lipid values in primary hypertriglyceridemia (HT).

Hypertriglyceridemic patients generally show a post-challenge hyperinsulinemia. In patients where carbohydrate intolerance coexists, increasing of reactive insulin is relatively diminished and delayed. In a group of 31 hypertriglyceridemic patients these characteristics of insulin increments in peripheral blood during a 50 g OGTT were constant: neither a low-fat (carbohydrate-rich) nor a high-fat (low carbohydrate) isocaloric, weight-maintaining diet had a significant influence on this parameter when compared with a standard diet (protein content unaltered throughout all diet periods). Glucose tolerance was significantly improved after the low-fat, high-carbohydrate diet. The results were neither correlated with the type of dietary inducibility of fasting triglyceride levels in individual cases nor with the sequence of diet periods prescribed. Hyperinsulinemia in hypertriglyceridemic patients is not believed to be the direct consequence of abnormal composition of the antecedent diet.

Carbohydrate Metabolism↗
PubMed1977

[Significance of fatty tissue hypertrophy for the metabolic risk].

The prevalence of diabetes mellitus, hypertriglyceridemia, and hypercholesterolemia rised with the weight index until Broca = 1,2; at higher degrees of obesity it remained constant or even slightly decreased Dresden Study). The subcutaneous adipose tissue of the abdomen exhibited against controls an excessive hypertrophy in subclinical diabetics, maturity onset-diabetics and hyperlipoproteinemics of types IIb, IV, and V. With this respect, between these groups there were no significant quantitative differences. Juvenile onset diabetics had abnormal small as well as large fat cells.

Adipose Tissue↗
PubMed1976

Metabolic effects of weight reduction in obese diabetics and nondiabetics.

A weight loss of about 10 kg was acheived by means of individual periods of total fasting, hypocaloric diets and physical activity in three groups of patients: maturity-onset diabetics, patients with pathological OGTT and overweight persons with normal OGTT. Adipocyte volume decreased in all groups, glucose tolerance improved. IRI curves showed a significant overall lowering and FFA concentrations during OGTT were dimished.

Adipose Tissue↗
PubMed1975

[Effect of weight reduction on carbohydrate and fatty-acid metabolism in obese, maturity-onset diabetic patients].

In 35 adipose maturity-onset-diabetics (27 women, 8 men, average age 48 years) we examined the influence of a 4--5-week slimming cure on the carbohydrate and fat metabolism. A significant decrease showed the index of ideal weight, volume of adipozytes, fasting free fatty acids concentration, triglyceride content of the liver as well as systolic blood pressure. The decrease of the triglycerides, of cholesterol and of the uric acid level in the serum could not be ascertained statistically. The reduction of weight did not cause an essential change of the basal and stimulated insulin concentrations, whereas the glucose tolerance clearly improved. After an observation period of 36.5 months behaviour of weight and form of therapy are analysed.

Age Factors↗
PubMedDate not supplied

Hyperinsulinemia in patients with low fractional catabolic rate of triglycerides.

In non-diabetic persons whose serum triglyceride (TG) concentrations ranged from normal to very high levels, endogenous TG turnover was measured using the radioglycerol method of Farquhar and coworkers. Insulin, FFA, and glucose concentrations were estimated during an oral glucose tolerance test. Stimulated insulin levels were correlated positively to TG concentrations and absolute TG turnover rates, and negatively to fractional TG catabolic rates. FFA concentrations had similar relationships, also in non-insulin-dependent diabetics. A more detailed analysis showed that elevated insulin and FFA levels - as an expression of peripheral insulin resistance - are typical finding in the kind of patients whose fractional TG catabolic rate is low [less than or equal to 0.210 (h-1)], irrespective of actual serum TG concentration. Our data do not suggest a stimulatory role of insulin for TG production.

Adult↗
PubMedDate not supplied

Computer program for iterative evaluation of fractional turnover rates by exponential regression: application to the turnover of VLDL-triglycerides in blood.

A microcomputer program ('EXREG') in GW BASIC was developed for fitting experimental data of A(T) to the equation A = A0 + A1.exp(-K.T) by exponential regression. In an iterative procedure K-values are tested to yield the maximum coefficient of determination. The accuracy of K is further improved in consecutive steps. The program is used to obtain the fractional turnover rate K of radiolabelled very low density lipoprotein (VLDL)-triglycerides in patients suffering from disturbances of lipid metabolism. A is the radioactivity of VLDL-triglycerides which is measured after isolation from blood. Seventeen consecutive blood samples are taken within a period of 24 h after injection of radioactive glycerol. T is the time after injection. The production rate of VLDL-triglycerides is calculated using K, the VLDL-triglyceride concentration, the body weight and height.

Computer Simulation↗
PubMedDate not supplied

Glucose-induced enhancement of hemin-catalyzed LDL oxidation in vitro and in vivo.

Growing evidence indicates that oxidative modification of low-density lipoprotein (LDL) is increased in diabetes mellitus; however, the mechanism(s) of this phenomenon is still unclear. gamma-Glutamyl semialdehyde (gammaGSA) is a product of hemin (Fe(3+)-protoporphyrin IX)-catalyzed oxidation of apolipoprotein B-100 (apoB- 100) proline and arginine residues. On reduction, gammaGSA forms 5-hydroxy-2-aminovaleric acid (HAVA). This report describes the application of sensitive HAVA assay, to characterize gammaGSA formation in LDL under normo- and hyperglycemic conditions, both in vitro and in vivo. In vitro studies revealed that apoB-100 proline and arginine residues are not oxidized to HAVA by HOCl or the myeloperoxidase/hydrogen peroxide (H(2)O(2)) oxidation system. Cu(2+), Cu(2+)/H(2)O(2), and Fe(2+) induced only minor HAVA formation. In contrast, the hemin oxidation system appeared reactive toward LDL apoB-100 proline and arginine residues. The resulting significant HAVA formation was specifically inhibited by a redox-inert ferric iron chelator. Glucose further enhanced hemin-induced increase in relative electrophoretic mobility of LDL and apoB-100 HAVAformation. In vivo we observed elevated concentrations of HAVA in LDL apoB-100 in patients with impaired glucose tolerance and with manifest diabetes mellitus. In conclusion, glucose promotes iron-mediated oxidation of apoB- 100 proline and arginine residues via a superoxide-dependent mechanism, thus rendering the LDL particles more atherogenic. The findings (a) identify a potential mechanism of enhanced atherogenesis in subjects with diabetes mellitus and (b) support the value of HAVA as a specific marker of LDL apoB-100 oxidation. Antioxid. Redox Signal. 7, 1507-1512.

Adult↗
PubMedDate not supplied

Elimination of lipofundin S during the intravenous fat tolerance test in patients with low, medium, and high fasting triglyceride concentrations.

The intravenous fat tolerance test with Lipofundin S (0.5 ml of 20% emulsion/kg body weight) was performed in 22 male nondiabetic patients. According to their fasting triglycerides (TG), the patients were arranged into three groups: low (less than 2.8 mmol/liter), medium (2.8-5.7 mmol/liter), and high (greater than 5.7 mmol/liter) concentrations. Fractional elimination rates of injected Lipofundin S decreased from 11.08 in low TG to 4.57%/min in high TG; they were positively correlated with fasting levels of high-density lipoprotein cholesterol but negatively with those of TG. The same pattern of correlations was observed with fractional catabolic rates of endogenous TG as measured after injection of tritium-labeled glycerol. The intravenous Lipofundin S load effected transient TG and free fatty acid elevations which were delayed in high TG. The elimination mechanisms of injected Lipofundin S and of endogenous TG are compared.

Adult↗
PubMedDate not supplied

Elimination kinetics of Lipofundin MCT: bolus injection and infusion compared.

Fifteen healthy young probands (nine males, six females) underwent an intravenous fat tolerance test (IVFTT) and, on the following day, a fat infusion lasting 6 hr. The emulsion tested was Lipofundin MCT 10%. One half of its triglyceride mass contains medium chain fatty acids. The IVFTT was started by injection of 0.1 g lipid per kg body weight into the fasting proband. Lipid elimination was estimated by measurement of light-scattering intensity of serum samples collected during a 60-min period. Individual fraction elimination rate constants covered a considerable range (K2 = 8.84 +/- 3.45%/min). The infusion test was performed at a rate of 0.1 g lipid per kg body weight and hr and lasted 6 hr. Serum triglyceride concentrations were determined enzymatically. They increased from 0.941 +/- 0.285 mmol/liter at the fasting state to a plateau level of 1.753 +/- 0.306 mmol/liter during infusion, and returned to initial levels 1 to 2 hr after the infusion was terminated. Individual triglyceride increments during infusion were significantly correlated with half-life periods of lipid elimination during IVFTT (r = 0.792, p less than 0.001). This relationship was derived using a model of the stationary state during infusion. We conclude that elimination kinetics of exogenous fat given either as bolus or infusion are ruled by the same fractional elimination rate constant K2. The IVFTT provides an estimate of the stationary triglyceride increment during a lipid infusion lasting several hr.

Adult↗
PubMedDate not supplied

Elimination and metabolism of a fat emulsion containing medium chain triglycerides (lipofundin MCT 10%).

Medium chain triglycerides (MCT) are supposed to be advantageous on account of rapid energy supply in parental nutrition. However, data on the elimination rate of MCT-containing emulsions during an intravenous fat-tolerance test (IVFTT) are scarce. We performed this test (0.1 g lipid/kg body weight) in 18 young healthy volunteers (nine females and nine males) using Lipofundin MCT 10% (50% MCT; egg phospholipids as emulsifier). Our results indicate that both elimination and metabolization of the emulsion are fast: a prompt decrease of light-scattering index and of triglyceride concentrations in serum, an immediate appearance of post-load fatty acids and of beta-hydroxybutyrate were observed. This was in good agreement with the findings obtained during 6-hr infusions in the same probands. Fractional elimination rates k2 obtained from light-scattering indices are 7.29 +/- 2.73%/min in males and 11.59 +/- 3.38%/min in females, indicating a higher removal capacity in women. In the same subjects, the corresponding k2 values for Lipofundin S 10% (containing only long chain triglycerides) were higher, reflecting an elimination rate that is faster due to the use of soya bean phospholipids as emulsifier. In comparison, k2 values based on the course of the triglyceride concentrations are generally lower.

3-Hydroxybutyric Acid↗