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Biomedical subjects

J Skrha

Publications and source records attributed to J Skrha.

At least 19 recordsLinked to original sources
PubMed1991

[Evaluation of the status of diabetes mellitus during a 2-year period using traditional methods and determination of glycosylated hemoglobin A1c and fructosamine in the blood].

In the course of two years the authors checked 23 diabetic patients (13 type 2, 10 type 1), using the traditional approach, by assessment of haemoglobin A1c and serum fructosamine. The patients were classified according to compensation into four and three groups resp. Assessment of haemoglobin A1c evaluated the patients, in the same group as the traditional evaluation in 57.7% into the best compensated group and in 62.5% into the worst compensated group. In fructosamine agreement with traditional evaluation in the best compensated group was in 84.2% and in the worst compensated group in 50.0%. In 40.2% the evaluation was in agreement for all three methods of evaluation, differences between evaluation according to haemoglobin A1c and serum fructosamine were recorded in 51.5%. Assessment of haemoglobin A1c and serum fructosamine improves information on the state of diabetes, concurrent estimation of both is, however, often associated with difficulties as regards interpretation. These problems are discussed in the presented paper.

Diabetes Mellitus↗
PubMed1991

[Diabetic angiopathies 1990].

In the submitted review the author summarizes recent knowledge on the biochemistry and pathophysiology of diabetic micro- and macroangiopathy. Hyperglycaemia and hyperinsulinaemia are the main cause of a complicated complex of changes which take place at different levels of the organism. Their consequence is an irreversible affection of the vascular wall with a subsequent effect on the organism as a whole.

Diabetic Angiopathies↗
PubMed1991

A six-year follow-up of the relationship between N-acetyl-beta-glucosaminidase and albuminuria in relation to retinopathy.

Fifty patients with Type 1 diabetes mellitus were observed over 6 years. Serum and urinary N-acetyl-beta-glucosaminidase (NAG) activity, and albuminuria were measured in groups of patients subdivided according to ophthalmological findings. Significantly higher mean serum NAG activity was found at the beginning of the study in patients who later developed diabetic retinopathy in comparison with those who did not (geometric mean (2SD range) 19.7 (12.4-31.2) vs 14.4 (9.5-22.7) U l-1, p less than 0.01). Urinary NAG activity was significantly higher in all groups of diabetic patients than in healthy control subjects (p less than 0.05). A significant increase in albumin:creatinine ratio during the study was found in patients with newly developed diabetic retinopathy compared with patients who did not (at 6 years 1.33 (0.40-4.43) vs 0.75 (0.24-2.31) g mol-1, p less than 0.01). No differences in either biochemical variable were found between hypertensive and normotensive diabetic patients at the end of the study. The results suggest that both serum NAG activity and albuminuria may serve as early functional indicators of diabetic retinopathy.

Acetylglucosaminidase↗
PubMed1991

N-acetyl-beta-glucosaminidase and albuminuria in acromegaly.

Significantly increased albuminuria and N-acetyl-beta-glucosaminidase activity in serum and urine have been observed in acromegalic patients in comparison with healthy persons (P less than 0.001). No relationship between these biochemical variables and serum growth hormone or insulin concentration was found in our group of patients. Significant correlation was determined between urinary NAG activity and albuminuria of acromegalic patients (r = 0.84).

Acetylglucosaminidase↗
PubMed1990

[The development of theories on the mechanisms of insulin action].

In 1924 Laufberger formulated his block theory on the action of insulin. Its basic thesis that insulin prevents the new formation of glucose and its supply into the blood stream is still valid, although knowledge on the multiple action of insulin expanded substantially. The theory put forward in 1955 by Levine and Goldstein which ascribed all insulin actions to the influence on the cellular membrane permeability for glucose, could, however, not explain all data associated with insulin, the knowledge of which was expanded steadily. At present the mechanism of insulin action is explained most comprehensively by the concept based on the bond of insulin to its membrane receptor which by activation of tyrosine kinase it contains induces either cascade phosphorylation of intracellular protein kinases or (and) leads to the release of the "second messenger" from the cell membrane, i.e. of glycosyl-phosphatidyl inositol. In both instances activation of the glucose and amino acids transmitter from the medium into the cells results, as well as activation of enzymes catalyzing in the cell various degrees of carbohydrate, fat and protein metabolism.

Czechoslovakia↗
PubMed1990

[Fructosamine--a dynamic indicator of compensation in diabetes].

The serum fructosamine concentration was evaluated in 22 diabetics on admission to hospital and after intensified treatment with an insulin pump which was indicated on account of decompensation of diabetes. The drop of the mean glucose concentration in blood after 12 days of treatment correlated with the statistically significant drop of the serum fructose concentration (r = 0.69, p less than 0.001). Between the glucose and fructosamine serum concentration no relationship was observed, as long as the mean glucose concentration was calculated for a period shorter than the previous seven days. A highly significant correlation was observed between the rate of fructosamine decline and the mean blood sugar level (r = 0.94, p less than 0.001). From the dynamic changes ensues that when the mean blood sugar level declined by 1 mmol/l, the fructosamine level declined on average by 0.13 mmol/l. The results suggest a more rapid turnover of glycosylated proteins, as compared with data in the literature pertaining to non-glycosylated proteins.

Adult↗
PubMed1990

[Analysis of dynamic changes in glycosylated blood proteins using a computer model].

UNLABELLED: The authors elaborated a computer model of albumin glycosylation based on the irreversible glycosylation reaction with first order kinetics. The dynamics of changes of glycosylated albumin in relation to the glycaemic profile was confirmed with an older model of haemoglobin glycosylation. By means of regression analysis parameters of the model in three groups of patients were calculated. CONCLUSION: 1. Stratification of the red cell pool is the reason why there is a smaller clinical difference between glycosylated protein and haemoglobin than corresponds to their half-times. 2. Glycosylated proteins are probably eliminated more rapidly than non-glycosylated ones. 3. Higher levels of glycosylated proteins sometimes do not correspond to model calculations are probably due to other factors.

Computer Simulation↗
PubMed1990

Plasma free N-terminal fibronectin 30-kDa domain as a marker of endothelial dysfunction in type 1 diabetes mellitus.

The plasma free N-terminal fibronectin 30-kDa domain was measured in 44 type 1 diabetic patients and in 20 healthy subjects. A significantly raised mean concentration of a free N-terminal fibronectin 30-kDa domain was found in plasma of diabetic patients with proliferative retinopathy as compared with healthy persons (P less than 0.001). A positive correlation was observed between free N-terminal fibronectin 30-kDa domain and von Willebrand factor in plasma of all examined subjects (r = 0.62, P less than 0.01). A similar correlation was present between 30-kDa domain and albuminuria (r = 0.56, P less than 0.01). However, no relationship was found between fibronectin 30-kDa domain and control of diabetes as assessed by fructosamine concentration. The free N-terminal fibronectin 30-kDa domain may be used as a marker of actual endothelial cell dysfunction in diabetes.

Adult↗
PubMed1990

The effect of long-term treatment by the angiotensin I-converting enzyme inhibitor enalapril on renal function and left ventricular hypertrophy in severe essential hypertension.

The therapeutic effect of long-term enalapril administration was studied in 20 patients with severe essential hypertension (EH), resistant to intensive therapy with a combination of 3 or 4 antihypertensive drugs. Addition of enalapril (Renitec MSD from 5 to 40 mg/day) to the previous therapy allowed to maintain blood pressure within limits not exceeding 150/95 mmHg during a 12-month study in more than 80% of previously resistant patients. Left ventricular hypertrophy regressed in all patients and dilatation of the left ventricle seen in 4 patients disappeared during enalapril treatment. Serum sodium creatinine did not change significantly. Serum potassium increased slightly but remained within the normal range. Proteinuria had a tendency to diminish and N-acetyl-beta-D-glucosaminidase activity in the urine dropped within normal limits. Based on their results, the authors conclude that enalapril is suitable for the long-term treatment of patients with severe EH, resistant to intensive antihypertensive therapy, with minimal side effects, good tolerance and a tendency for amelioration of cardiac and renal function.

Adrenergic beta-Antagonists↗
PubMed1990

Analysis of glycosylated serum protein changes using a computer model.

UNLABELLED: The authors devised a computer model of albumin glycosylation based on irreversible glycosylation reaction of first-order kinetics. The dynamism of glycosylated albumin changes in relation to glycaemic profiles was compared with an earlier model of haemoglobin glycosylation. A non-linear regression analysis was employed to calculate the parameters of the model in three groups of patients. CONCLUSIONS: 1. Erythrocyte pool stratification accounts for the smaller clinical difference between glycosylated protein and haemoglobin than would correspond to their respective half-life values. 2. Glycosylated proteins are probably eliminated more rapidly than non-glycosylated proteins. 3. Higher levels of glycosylated proteins are occasionally at variance with model calculations, a fact which is probably due to other factors.

Computer Simulation↗
PubMed1989

[The Biostator in the diagnosis and therapy of organic hyperinsulinism].

In 12 patients with the diagnosis of organic hyperinsulinism the authors examined the carbohydrate metabolism on a Biostator, using the method of stabilized glycaemia. They found a highly significantly reduced tissue sensitivity to insulin at the same time a reduced metabolic insulin turnover as compared with healthy subjects (p less than 0.001). Simultaneously they examined the acute action of diazoxide (Proglicem) treatment to which the patients responded in two ways. In one group a decline of the insulin level occurred and the tissue sensitivity to insulin rose, while patients in the second group responded by a rise of serum insulin but there was no response in the insulin sensitivity. In this second group diazoxide treatment obviously does not eliminate hypoglycaemic attacks. Examination on the Biostator thus makes it possible to decide whether conservative treatment is indicated in organic hyperinsulinism.

Adult↗
PubMed1989

N-acetyl-beta-glucosaminidase and albuminuria in normal and diabetic pregnancies.

Fourteen diabetic women without signs of nephropathy were examined during pregnancy. Serum fructosamine concentration indicating short-term metabolic control of diabetes was normalized at the beginning of the second trimester and was within the normal limits till the delivery. A gradual increase of N-acetyl-beta-glucosaminidase activity in serum and urine has been found during pregnancy in diabetic and healthy women. No significant differences of N-acetyl-beta-glucosaminidase activities were observed between the above groups. A successive increase of albuminuria during pregnancy was present in diabetic and healthy women with about 10-times higher values at delivery. A significant positive correlation was observed between albuminuria and urinary NAG activity in both groups of pregnant women (r = 0.77). We did not find any deterioration in N-acetyl-beta-glucosaminidase activities and albuminuria in seven diabetic women one year after delivery.

Acetylglucosaminidase↗
PubMed1989

Use of euglycaemic clamping in evaluation of diazoxide treatment of insulinoma.

The use of diazoxide in patients with insulinoma has been evaluated using the euglycaemic clamp technique. There was significantly reduced mean tissue sensitivity to insulin, expressed as the ratio of glucose disposal rate to serum insulin concentration (M/I), in untreated patients compared to the control group. The metabolic clearance rate of insulin (MCRI) was reduced in the patients before treatment in comparison with the controls. The administration of diazoxide (Proglicem1) for three days (3 mg.kg-1 per day) caused a fall in serum insulin concentrations, together with an increase in the metabolic clearance rate of insulin and increased tissue sensitivity to insulin.

Adenoma, Islet Cell↗
PubMed1989

Laboratory detection of the early stages of diabetic nephropathy.

Three laboratory indicators of impaired renal function (microalbuminuria (MA), N-acetyl-beta-glucosaminidase (NAG), beta-2-microglobulinaemia (beta-2-M)) were studied in sixty diabetics of type 1. 10 times higher MA levels were found in a subgroup of diabetics with identifiable diabetic retinopathy (DR). In a subgroup of diabetics with normal values of excreted albumin the mean MA value was significantly higher than in those who had already contracted DR. Pathological levels of NAG and beta-2-M were mostly seen in those patients who also had pathological MA results. In only four cases were increased NAG or beta-2-M values as the first and only pathological parameter indicative of possible renal involvement due to diabetic nephropathy.

Acetylglucosaminidase↗
PubMed1989

[Fibronectin].

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Fibronectins↗