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Biomedical subjects

P Stolba

Publications and source records attributed to P Stolba.

At least 55 records · Page 3Linked to original sources
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

[The effect of 1-p-bromphenyl-5-mercapto-1,2,3,4-tetrazole (Br FMT) on thyroid gland function in rats].

The effects of the novel potential thyrostatic agent 1-p-bromphenyl-5- mercapto-1,2,3,4-tetrazole (Br-FMT) on the serum levels of thyroxine, thyrotropic hormone (TSH), the content of cyclic adenosine monophosphate (cAMP) in the thyroid gland, the body weight and the weight of the thyroid gland in liver transaminases and the white blood picture in Wistar strain rats were investigated. The effect of Br-FMT was compared with the effect of the well-known thyrostatic agent and goitrogen ethylester of 3-methyl-2-thio-4-imidazoline-1- carboxylic acid, carbimazole (Spofa) and with the control group, which received placebo only. The drugs tested were administered to animals in the dose do 7.5 mumol/animal via a gastric tube for the period of one month. Br-FMT and carbimazole decreased the level of serum thyroxine in a statistically significant manner. The serum level of TSH was evidently decreased after Br-FMT; it was not changed after administration of carbimazole in the given dose. The content of cAMP in the thyroid gland was significantly increased only after carbimazole. The weight of the thyroid gland was not significantly changed in any group under study, though after carbimazole the mean value was higher by a quarter as compared with the control group. The body weight and white blood picture were not significantly changed in all groups under study. ALT and AST values were evidently lower after carbimazole and Br-FMT, most probably due to the hypothyroid state of the animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Estradiol-induced adenohypophyseal growth reaction and beta-adrenergic receptors.

The effect of administration of estradiol benzoate on beta-adrenergic receptors of rat adenohypophyseal cells was studied. Twenty days' administration of estradiol benzoate was followed by an increase of adenohypophyseal weight and a decrease in specific binding of 3H-dihydroalprenolol (3H-DHA). In contrast to thyroid hormone treatment which induced an increase in 3H-DHA binding, thyroid hormone treatment decreased both the growth reaction and the reaction of beta-adrenergic receptors after estradiol. Although the relationship between the adenohypophyseal receptors and the growth reaction is unclear, changes in beta-adrenergic receptors after hormonal therapy can be one of pathophysiological conditions that may influence this reaction.

Animals↗
PubMed1991

[Hypertension in patients with polycystic kidneys--the effect of volume expansion].

Arterial hypertension is found in as many as 75% patients with autosomal dominant polycystic kidneys with normal renal function, its pathogenesis is however not quite clear so far. The authors examined 16 patients with polycystic kidneys with normal or only slightly reduced renal function (plasma creatinine lower than 140 umol/l), 8 of these patients were normotonic (N) and 8 hypertonic (H). In all examined subjects right-sided cardiac catheterization was performed with assessment of the minute cardiac volume by thermodilution. To all patients in the course of one hour 1500 ml saline per 70 kg body weight were administered and the haemodynamic examinations were repeated after termination of the infusion. In all subjects before and after expansion the plasma renin activity was assessed (PRA), as well as plasma aldosterone (PA), plasma catecholamines (PC) and the atrial natriuretic factor (ANF), the renal blood flow and glomerular filtration by means of clearance and extraction of PAH and inulin clearance. The authors did not find differences in plasma concentrations, cardiac output and splanchnic and renal ANF extraction in groups N and H, nor in PRA, PA and PC. Volume expansion led in both groups to a comparable rise of ANF and suppression of PRA and PA. Group H did not differ from group N in any of the investigated haemodynamic and renal parameters except for systemic vascular resistance. In hypertensive patients before expansion a close correlation was found between pressure in the pulmonary artery in a wedged position and diuresis (r = 0.935, p less than 0.01) and natriuresis (r = 0.895, p less than 0.01). The volume expansion was in both groups associated with a comparable rise of diuresis, the haemodynamic response of patients N and H was however quite different. While in patients of group N a decline of the systemic vascular resistance occurred as well as an increase of the minute volume without a change of the renal flow and glomerular filtration, in hypertonic patients the systemic vascular resistance and minute volume did not change but there was a significant rise of the renal flow and glomerular filtration. The relationship of diuresis and natriuresis of hypertensive patients with polycystic kidneys to volume parameters and the rise of the renal perfusion pressure during volume expansion indicates the importance of pressure natriuresis for ensuring the sodium and volume homeostasis in these patients.

Humans↗
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

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

Effect of calcitriol and trifluoperazine on glucose stimulated B cell function in healthy humans.

The authors investigated the effects of pharmacological doses of calcitriol (1,25(OH)2-vitamin D3) and trifluoperazine on metabolic and hormonal indicators of glycoregulation in the course of the intravenous glucose tolerance test (IVGTT) in healthy subjects. Calcitriol administered by the oral route for four days, 3 micrograms/d, did not alter the blood sugar and plasma IRI levels at rest nor glucose stimulated values throughout the IVGTT. The slight increase of the glucose assimilation coefficient was not significant, as compared with values of the control test (Kg = (3.9 +/- 0.5) x 10(-2) [min-1] vs. Kg = (3.4 +/- 0.3) x 10(-2) [min-1], respectively). C-peptide plasma levels after calcitriol were slightly higher, significantly during the 14th minute following glucose administration (p less than 0.05), while the two-peak shape of the curve was preserved. Trifluoperazine administered by the oral route for seven days, 10 mg/d, did not significantly affect the blood sugar, IRI and C-peptide values at rest nor glucose induced values throughout the IVGTT nor values of glucose assimilation (Kg = (3.0 +/- 0.4) x 10(-2) [min-1] vs. Kg = (3.4 +/- 0.3) x 10(-2) [min-1] in the control test). In conclusion, neither calcitriol nor trifluoperazine treatment leads to clinically significant alteration of glycoregulation.

Adult↗
PubMed1990

Increased number of beta-adrenergic receptors on cells of the rat adenohypophysis after thyroid hormone administration.

The authors studied the effect of administration of thyroid hormones on the beta-adrenergic receptors of rat adenohypophyseal cells. The administration of triiodothyronine and thyroxine was followed by an increase in specific binding for 3H-dihydroalprenolol. No significant differences were found in cyclic adenosine monophosphate levels before and after isoprenaline stimulation. The significance of changes in these receptors for the hyperplastic reaction after oestrogens is discussed with reference to the inhibitory effect of the thyroid hormones on hyperplasia of the adenohypophyseal cells after the administration of oestradiol.

Animals↗
PubMed1990

[Manifestations of dysfunction of the proximal tubules after intravenous urography].

The aim of the work was to investigate functional changes of tubular cells after i.v. urography. As evidence the authors used assessment of urinary levels of membrane-bound enzymes--alkaline phosphatase (AP), gamma-glutamyl-transpeptidase, lysosomally bound enzymes N-acetyl-beta-D-glucosaminidase and its isoenzyme B and the low molecular protein, beta-2-microglobulin. The above substance were assessed in 15 patients with different nephropathies where i.v. urography was indicated. The examinations were made in 24-hour urine samples before i.v. urography and in two 24-hour samples after administration of the contrast substance. In all patients a significant rise of tubular enzyme excretion was observated as well as of beta-2-microglobulin. The greatest rise was recorded in alkaline phosphatase in the second sample after administration of the contrast substance (432% of the initial value). Beta-2-microglobulin and N-acetyl-D-glucoseaminidase rose already during the first collection period (B2M to 357% and NAG to 181% of the initial values). The authors conclude that i.v. urography made by hyperosmolar iodinated preparations (Verografin, Iodamide) significantly affects the function and integrity of the proximal tubule. The applied spectrum of examinations is suitable also for further investigations of the effect of contrast substances on cells of the proximal renal tubule.

Adult↗
PubMed1990

[The effect of streptozotocin-induced diabetes treated with insulin on the metabolism of calcium, magnesium and phosphorus].

In a group of rats with streptozotocin induced diabetes the excretion of calcium, magnesium, phosphorus and creatinine in urine was investigated and the calcium, magnesium and phosphorus content of bone in relation to the duration of the disease. The authors observed that in diabetic rats the urinary losses of calcium, magnesium and phosphorus increase significantly. The creatinine excretion is also significant but lower in relation to calciuria and therefore the value of Nordin's index in diabetic rats rises markedly. Bone of diabetic rats in the early stage of diabetes (32 days) loses magnesium, while the calcium and phosphorus content does not change significantly. During longer persistence of severe diabetes (70 days) a significant drop of all three minerals in bone was observed. The bones of diabetic animals on the 70th experimental day were macroscopically smaller and were very fragile. The authors' findings suggest a marked influence of streptozotocin diabetes on calcium phosphate metabolism and bone metabolism, in particular on account of STZ diabetes, on an early drop of magnesium in bone. The possible impact of this finding for clinical practice will have to be tested further.

Animals↗
PubMed1990

[Early diagnosis of nephropathy in type I diabetics].

In 68 type I diabetics without permanent proteinuria, mean age 28 +/- 9 years, where diabetes was detected at the age of 14 +/- 7 years and persists for 14 +/- 8 years the urinary excretion of albumin and beta-2-microglobulin was assessed. The results were evaluated in relation to the persistence of diabetes, the blood pressure reading, family-history of diabetes and type of insulin therapy. In addition to microalbuminuria in 29% of the subjects which is a manifestation of glomerular damage, the authors detected in 58% elevated beta-2-microglobulin excretion indicating early changes of the proximal tubule. There was a relationship between microalbuminuria and "relative hypertension" which enhances albumin excretion and increases the risk of diabetic nephropathy. The relationship between microalbuminuria and a positive family-history of diabetes supports the hypothesis of a genetic background for the possible development of nephropathy. There was also a relationship with the duration of diabetes and the favourable effect of prolonged intensive insulin treatment. The clinical impact of beta-2-microglobulinuria in the diagnosis of the incipient stage of diabetic nephropathy must be tested in future investigations.

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

[The effect of Sinecal fiber on compensation in type 2 diabetics].

The authors investigated in 28 type 2 diabetics the effect of addition of 21 g Sinecal fibre to the normal diet on the glucose and lipid metabolism. The value of C,peptide was significantly influenced after breakfast and a single dose of Sinecal. The other investigated parameters (blood sugar on fasting and after a meal, glycosuria, glycosylated proteins, C-peptide on fasting and after a meal, triacylglycerol and cholesterol) were not influenced by a single nor by long-term intake of Sinecal. Further development of fibre preparations with better tolerance and a greater effect on the glucose metabolism is desirable.

Aged↗
PubMed1989

Effect of the beta-adrenergic substances propranolol, alprenolol and isoprenaline on cAMP production in bovine thyroid slices.

The effect of the beta-adrenergic blockers L-alprenolol and DL-propranolol and of the beta-adrenergic agonist L-isoprenaline on the basal and thyrotropic hormone(TSH)-stimulated cyclic adenosine-monophosphate (cAMP) level in bovine thyroid slices was studied. The main basal cAMP level in bovine thyroid slices was 3 pmol/mg tissue. TSH stimulated cAMP production in correlation to the concentration. Maximum stimulation was achieved with a TSH concentration of 10 mU/ml. The beta-blockers DL-propranolol and L-alprenolol caused 74 and 77% inhibition of TSH-stimulated cAMP synthesis respectively. The beta-adrenergic agonist L-isoprenaline did not significantly affect either the basal or the TSH-stimulated cAMP level. The role of the beta-adrenergic receptor system in the regulation of TSH-stimulated cAMP synthesis is discussed.

Alprenolol↗
PubMed1989

[5-Substituted 3-mercapto-4H-1,2,4-triazoles as a potential thyrostaticagent].

Within the framework of the study of the relationships between the structure and thyreostatic activity of cyclic analogues of thiourea, a series of 5-substituted 3-mercapto-4H-1,2,4-triazoles was prepared in order to answer the question of how the presence of another nitrogen atom in position 1 and the presence of the substituent in position 5 would influence thyreostatic activity. The synthesis was based on 1-acylsubstituted thiosemicarbazides which were cyclized to the pertinent 3-mercapto-4H-1,2,4-triazoles. Furthermore, esters of dicarboxylic acids were used, which with thiosemicarbazide in alcoholate yielded the pertinent mercaptotriazoles. Selected 5-substituted 3-mercapto-4H-1,2,4-triazoles were tested on adult male rats of Wistar strain. The effects of the agents under study on the level of serum thyroxine (T4), total body weight, heart weight, thyroid gland weight, and the number of leucocytes were investigated. The results of the tests show that whereas the presence of nitrogen in position 1 influenced the thyreostatic activity of the agents prepared in an insubstantial manner only, the presence of a substituent in position 5 acts, except a methyl or ethyl group, dystherapeutically, and with the increasing volume of the substituent therapeutic activity disappears regardless of the fact whether an aliphatic or aromatic substituent is concerned.

Animals↗
PubMed1989

[Evaluation of glycosuria in normal glucose tolerance].

In 52 subjects where after 10.6 +/- 7 years after detection of glycosuria on fasting normal glucose tolerance persists some risk factors and early biochemical changes indicating possible later development of diabetes were evaluated. 73% of the subjects had a positive family-history of diabetes and 61% were obese. In 42% of the subjects during the present examination glucose in urine was detected only after a glucose load. In 35% of the subjects pathological serum values of glycoproteins were found and their mean fasting blood sugar levels and levels 60 minutes after a glucose load were significantly higher, although in the range of normal oGTT, as compared with the group with normal glycoprotein levels. 21% had pathological values of N-acetyl-beta-D-glucosaminidase levels in serum and urine and concurrently significantly higher IRI values 60 and 120 minutes after a glucose load, than the group with a normal value. In obese subjects, as compared with those with a normal body weight, there were significantly higher mean blood sugar levels on fasting and 60 minutes after a glucose load and the same applies to IRI levels on fasting and after 60 minutes following stimulation. The authors discuss the causes and interrelations of the assembled results.

Adult↗