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Biomedical subjects

E Franek

Publications and source records attributed to E Franek.

At least 19 recordsLinked to original sources
PubMed1999

Coadministration of albumin and furosemide in patients with the nephrotic syndrome.

BACKGROUND: In patients with nephrotic syndrome, the natriuretic effect of furosemide (FU) is diminished. The effect of coadministration of FU and human albumin (HA) has remained controversial. METHODS: In a double-blind, placebo-controlled study, nine nephrotic patients (six males, 48 +/- 4 years) on standardized sodium chloride intake, in random order on three separate days, received by intravenous administration for 60 minutes either (a) 60 mg FU plus a sham infusion, (b) 60 mg FU plus 200 ml of a 20% solution of HA, or (c) sham infusion plus 200 ml of a 20% solution of HA. Urinary volume, sodium, albumin and FU excretion, renal hemodynamics, and plasma atrial natriuretic factor concentration were assessed. RESULTS: Administration of FU alone significantly (P < 0.01) increased mean cumulative urinary sodium (259 +/- 30 mmol) and volume excretion (2684 +/- 167 ml) in the first eight hours as compared with the HA infusion alone (118 +/- 12 mmol, 1827 +/- 141 ml). The coadministration of FU and HA caused an even more marked increase (P < 0.01 vs. HA alone) of urinary sodium (312 +/- 28 mmol) and volume excretion (3230 +/- 201 ml); the difference to FU administration alone was significant (P < 0.05). Plasma atrial natriuretic factor, serum albumin concentration, and urinary albumin excretion increased significantly on both HA infusion days, whereas urinary excretion of FU remained unchanged with HA coadministration. Glomerular filtration rate (CIn) was not significantly affected by any of the infusion protocols, but effective renal plasma flow (CPAH) increased significantly on both HA infusion days. CONCLUSIONS: Coadministration of HA potentiates the action of FU in patients with the nephrotic syndrome, but only modestly. This effect is mediated by changes in renal hemodynamics.

Adult↗
PubMed1999

[Electrically enhanced damaged tissues healing. Part I: direct current in bone healing].

The reasons of investigators' interest of damaged tissues healing with electrical current in concise form are represented by the authors. The nonunions and pseudarthroses healing with direct current through negative polarized electrode is described in this article. Hypothetic biological healing mechanisms (as piezoelectric activity, streaming potentials, electric properties of glycosaminoglycan etc.) are discussed. Technical data of currents and their antibacterial properties are described.

Electric Stimulation↗
PubMed1999

[Electrically enhanced damaged tissues healing. Part II: direct and pulse current in soft tissue healing].

Methodology of soft tissues wounds, ulcers and pressure sores healing with direct current is described by the authors. Results of clinical trials and animal experiments are represented, as well as technical and using data. Electrical properties of damaged tissues (e. i. skin battery, vascular-interstitial closed circuits etc.) and probable electrical healing mechanisms are discussed. Effects of electrical current on batteries are described. Inductive and capacitive coupling of electric and magnetic fields, and high voltage electrostimulation for enhance tissue healing are also described in the article.

Animals↗
PubMed1998

Insulin resistance and hyperinsulinemia are already present in patients with incipient renal disease.

In uremic patients resistance to the action of insulin has been documented, but it is not known at what stage of renal disease it appears. We therefore examined 29 patients with IgA glomerulonephritis (IgAGN) and 21 patients with adult polycystic kidney disease (ADPKD) in different stages of renal failure, and in addition, healthy age-matched subjects. Insulin sensitivity and other variables of glucose metabolism were assessed using a frequent sampling intravenous glucose tolerance test (minimal-model technique). Glomerular filtration rate (GFR) was assessed in renal patients using the inulin-clearance technique. Mean insulin sensitivity index (SI), that is, insulin sensitivity, was significantly lower (P < 0.001) in all patients combined than in matched healthy subjects (N = 16; 14 males, mean age 42 +/- 3 years; mean SI 8.6 +/- 0.8 min-1 uU/ml). The mean SI was not significantly different in patients with renal disease of immune (IgAGN) or non-immune (ADPKD) origin, and it was not correlated with GFR (r = 0.01, P < 0.52), intact PTH (r = -0.23, P < 0.11) or calcitriol concentration (r = -0.03, P < 0.82). Consequently, the mean SI was similar in renal patients with GFR within the normal range (N = 19; 17 males, mean age 41 +/- 2 years; mean GFR 119 +/- 5 ml/min/1.73 m2; 5.1 +/- 0.7 min-1 uU/ml), in patients with mild to moderate renal failure (N = 16; 15 males, 46 +/- 3 years; 67 +/- 4 ml/min/1.73 m2; 5.1 +/- 0.7 min-1 microU/ml) and in patients with advanced renal failure (N = 15; 13 males, 46 +/- 3 years; 25 +/- 2 ml/min/1.73 m2; 4.7 +/- 0.6 min-1 uU/ml). Mean fasted plasma insulin concentration, the area under the curve for plasma insulin concentration (AUC) and total insulin delivery (TID) during the glucose tolerance test were significantly higher in patients than in healthy subjects, reflecting hyperinsulinemia in renal patients. Further, fasted plasma insulin concentration (r = -0.32, P < 0.009), AUC (r = -0.62, P < 0.0001) and TID (r = -0.34, P < 0.004) in patients were significantly correlated with insulin sensitivity (SI). The present data document that insulin resistance and concomitant hyperinsulinemia are present early in the course of renal disease, that is, even in patients with GFR within the normal range, irrespective of the type of renal disease. This observation may have potential implications with respect to the high cardiovascular morbidity and mortality in patients with renal disease.

Adult↗
PubMed1998

Effects of smoking on renal hemodynamics in healthy volunteers and in patients with glomerular disease.

Patients with renal disease who smoke have a poor renal functional prognosis, but the mechanisms involved have not been explored. In this controlled study, the effects of smoking and sham smoking were compared in 15 healthy normotensive volunteers. All were occasional smokers and abstained from smoking for 48 h as documented by urinary cotinine measurements. These data were compared with those of seven patients with biopsy-confirmed IgA glomerulonephritis, also occasional smokers. Renal clearance examinations were obtained after hydration in the supine position before and while smoking two cigarettes or sham cigarettes in random order on 2 consecutive days. GFR and effective renal plasma flow were determined using In111-diethylenetriamine penta-acetic acid and 131I-hippurate with a dual tracer infusion clearance technique. In an ancillary study with six volunteers, the effect of smoking was compared with the effect of nicotine-containing chewing gum. In healthy volunteers, sham smoking caused a minor but significant increase of mean arterial pressure (MAP) and GFR with no significant change of effective renal plasma flow, filtration fraction (FF), or renovascular resistance. Smoking caused a significant and more marked increase of MAP (from baseline 92.8+/-8.98 to 105+/-7.78 mmHg) and heart rate (from 61.7+/-7.52 to 86.4+/-9.87 min(-1)), accompanied by a significant increase in arginine vasopressin (from 1.27+/-0.72 to 19.9+/-27.2 pg/ml) and epinephrine (from 37+/-13 to 140+/-129 pg/ml). During smoking, GFR decreased in all but one volunteer (from 120+/-17.7 to 102+/-19.3 ml/min per 1.73 m2), and this was accompanied by a significant decrease of FF (from 21.3+/-4.24 to 17.4+/-3.41%) and an increase in renovascular resistance (from 97.6+/-27.2 to 108+/-30.4 mmHg x min/ml per 1.73 m2). These findings were reproduced with nicotine-containing chewing gum. In contrast, when patients with IgA glomerulonephritis smoked, a similar increment in MAP was noted, the changes of FF were not uniform, and a small but consistent increase of urinary albumin/creatinine ratio was observed. An additional 20 volunteers were subjected to the smoking arm of the study for statistical evaluation of the GFR change in patients. The difference between the change of GFR between all volunteers (n = 35) and patients (n = 7) was significant (P < 0.005). It is concluded that the known effects of smoking and nicotine on the sympathetic nervous system and on systemic hemodynamics are accompanied by significant acute changes in renal hemodynamics and albuminuria. These findings are of interest because of the known effects of smoking on progression of renal disease.

Adult↗
PubMed1997

Renal function in the elderly: impact of hypertension and cardiac function.

In senescence renal function is thought to decline markedly even in the absence of renal disease. It has also been proposed that the changes in renal function with age are not uniform and that confounding factors such as hypertension or atherosclerosis may play a role. We performed a comprehensive study to compare several aspects of renal function in four groups: (i) young healthy normotensive subjects (N = 24; 13 males; mean age 26 +/- 3 years); (ii) elderly healthy normotensive subjects (elderly NT; N = 29; 13 males; 68 +/- 7 years); (iii) elderly treated and untreated hypertensive patients (elderly HT; N = 25; 13 males; 70 +/- 6 years); and (iv) elderly patients with compensated mild to moderate heart failure (elderly HF; N = 14; 6 males; 69 +/- 6 years). Compared to young subjects mean GFR (C(In)) and ERPF (C(PAH)) were significantly lower in the elderly, despite similar mean plasma creatinine levels (young, 121 +/- 11, 650 +/- 85 ml/min/1.73 m2; elderly NT, 103 +/- 11, 486 +/- 102; elderly HT, 103 +/- 13, 427 +/- 55; elderly HF, 92 +/- 14, 377 +/- 103). Nevertheless, GFR was within the normal range in the majority of elderly NT and HT, but not in elderly HF. ERPF was significantly lower in elderly HT as compared with elderly NT, and still lower in elderly HF. Mean renovascular resistance and filtration fraction were significantly higher in the elderly, particularly in elderly HT and HF as compared with the young. Mean fractional excretion of Na+ was similar in all groups studied, but the lithium clearance was significantly lower in the elderly, suggesting a greater proximal and less distal sodium reabsorption in senescence. In the elderly, mean PTH concentration and urinary excretion of pyridoline cross-links were significantly higher and mean 25-(OH)D3, calcitriol and phosphate concentrations significantly lower; the correlation between PTH and GFR was significant (r = -0.432, P < 0.001). The results document that the decrease in renal hemodynamics with senescence is less marked than suggested by some studies using less stringent methodology and inclusion criteria. Comorbid conditions confound renal function in the elderly. Age-associated changes in renal hemodynamics are accompanied by significant alterations of renal hormones and of renal sodium handling.

Adult↗
PubMed1997

Abnormal pulsatile secretion of growth hormone in non-insulin-dependent diabetes mellitus.

OBJECTIVE: Studies of GH secretion in patients with non-insulin dependent diabetes mellitus (NIDDM) have produced conflicting results. We aimed to differentiate the effects of obesity and metabolic control on pulsatile GH secretion in patients with NIDDM. DESIGN: Blood sampling every 15 min from 22.00 hours to 08.00 hours after a fasting period of at least 3 h. PATIENTS: 13 male NIDDM patients, 9 healthy control subjects matched for age and BMI, and 6 lean subjects matched for age. MEASUREMENTS: Measurement of GH by a novel ultrasensitive chemiluminescence assay. Analysis of concentration vs time profiles by a multiparameter deconvolution technique. RESULTS: GH burst frequency was increased in the NIDDM (0.82 +/- 0.28 h-1) compared with both control groups (lean: 0.6 +/- 0.11; obese: 0.56 +/- 0.19). GH burst mass was decreased in patients (1.57 +/- 0.98 micrograms/l.min) and in obese controls (1.46 +/- 1.44) compared to lean controls (3.71 +/- 3.88). These differences resulted in a significantly higher nocturnal pulsatile GH secretion rate in the lean compared to the obese controls, whereas in the patient group enhanced GH burst frequency compensated for reduced burst mass. The characteristics of GH secretion were not related to nocturnal or early morning blood glucose concentrations. However, GH secretion rate was correlated positively with HbA1c (r = 0.57; P = 0.04), and negatively with plasma C peptide concentrations. CONCLUSIONS: The specific increase in GH burst frequency previously described in insulin-dependent diabetes mellitus is also present in NIDDM. However, GH hypersecretion does not occur because GH burst mass is reduced in proportion to the degree of obesity. The effect of diabetes on the hypothalamic control of GH release appears to be determined by the quality of long-term glycaemic control.

Analysis of Variance↗
PubMed1997

No effect of calcitriol on insulin-mediated glucose uptake in healthy subjects.

Administration of active vitamin D (calcitriol) improves insulin sensitivity in uraemic patients. These patients have subnormal plasma calcitriol concentrations in parallel with increased intact parathyroid hormone (PTH) concentrations. It is therefore unclear whether the improvement in insulin sensitivity results from a direct effect of calcitriol or from amelioration of secondary hyperparathyroidism. So far, no evidence has been presented that insulin sensitivity is specifically affected by calcitriol in healthy subjects. We investigated the effect of (supra)therapeutic doses of calcitriol on insulin sensitivity in healthy volunteers. In a double-blind parallel group design, 18 healthy male subjects received in random order either placebo or 1.5 micrograms of calcitriol per day by mouth for 7 days. Insulin-mediated glucose uptake, i.e. insulin sensitivity, was assessed using the euglycaemic clamp technique. Mean glucose disposal rate, i.e. M-value, was not significantly affected by placebo or calcitriol treatment (placebo: 7.1 +/- 1.3 mg kg-1 min-1 before and 7.2 +/- 1.5 mg kg-1 min-1 after treatment; calcitriol 7.0 +/- 1.4 mg kg-1 min-1 and 7.2 +/- 1.4 mg kg-1 min-1). There were no significant changes in mean plasma glucose, insulin, phosphate, bicarbonate and ionized calcium concentrations after administration of placebo or calcitriol. Furthermore, platelet intracellular calcium concentration (assessed by fluorescence spectroscopy) and mean arterial blood pressure (24 h ambulatory measurement) did not change with placebo and calcitriol treatment. On the other hand, mean intact PTH concentration decreased significantly (P < 0.01) with calcitriol treatment, but not with placebo. In addition, mean 24 h urinary calcium excretion increased significantly (P < 0.05) with calcitriol administration but was unchanged with placebo. Administration of (supra)physiological doses of calcitriol has no effect on insulin sensitivity in healthy subjects, despite a significant decrease in PTH concentrations. These observations are compatible with the notion that the effect of calcitriol on insulin sensitivity is present only in uraemic calcitriol-depleted patients.

Administration, Oral↗
PubMed1997

Subacute infusion of physiological doses of parathyroid hormone raises blood pressure in humans.

BACKGROUND: Acute administration of parathyroid hormone (PTH) causes vasodilation and blood pressure decrease in experimental animals. This effect contrasts with the putative role of secondary hyperparathyroidism in the pathogenesis of hypertension of patients with renal failure. Uraemia is characterized by insulin resistance and hyperinsulinaemia. We therefore investigated whether subacute administration of physiological doses of human 1,34-PTH affects blood pressure under conditions of controlled insulin levels (euglycaemic clamp technique) in humans. METHODS: In a double-blind cross-over design 10 healthy male subjects received, on two occasions, in random order, for 2 h, either a sham infusion or an infusion of 200 units of 1,34-PTH. RESULTS: Mean ionized calcium concentration increased significantly (P < 0.01) within the normal range during euglycaemic hyperinsulinaemia, both with sham infusion (from 1.25 +/- 0.04 to 1.29 +/- 0.02 mmol/l) and with infusion of 1,34-PTH, but the increase was more marked with 1,34-PTH administration (from 1.26 +/- 0.05 to 1.33 +/- 0.07). In addition, mean platelet intracellular calcium concentration (by fluorescence spectroscopy) was unchanged with sham infusion (49.9 +/- 4.1 versus 50.3 +/- 5.0 nmol), but increased significantly (P < 0.05; paired t-test) after 1,34-PTH infusion (from 49.8 +/- 5.0 to 52.8 +/- 5.8). The infusion of 1,34-PTH resulted in a significant (P < 0.01) increase in mean MAP (from 84 +/- 5 to 88 +/- 5 mmHg) as compared with sham infusion (85 +/- 4 versus 86 +/- 4). The intra-individual changes in intracellular calcium concentration (delta[Ca2+]i) were significantly correlated to the changes in mean MAP (delta MAP) (r = 0.87, P < 0.001). In contrast to blood pressure, insulin sensitivity was not affected by 1,34-PTH infusion (M-value: 7.2 +/- 1.6 mg/kg per min) as compared with sham infusion (7.3 +/- 1.4). CONCLUSION: Subacute administration of physiological doses of parathyroid hormone under hyperinsulinaemic conditions significantly affects intracellular calcium and blood pressure in healthy subjects, but does not affect the action of insulin.

Adult↗
PubMed1997

Altered action of angiotensin II in patients with type 2 diabetes mellitus of recent onset.

OBJECTIVE: Angiotensin II (Ang II) increases insulin sensitivity in healthy volunteers. This effect is thought to be mediated, at least in part, by an increase in skeletal muscle blood flow. In the past it had been documented that some biological actions of Ang II are altered in diabetes. We addressed the issue of whether this is also true for its action on insulin sensitivity. DESIGN AND METHODS: Twelve healthy volunteers (aged 43+/-9 years) and 15 patients with type 2 diabetes mellitus (NIDDM) of recent onset (aged 45+/-9 years) were allocated in random order in a double-blind placebo-controlled design to be administered a sham infusion or an infusion of 2 ng Ang II/kg per min. Insulin-stimulated glucose uptake (the M value) was measured with the euglycaemic clamp technique, leg muscle blood flow (MBF) with plethysmography, blood pressure with a Dinamap device, and glomerular filtration rate and effective renal plasma flow with the steady-state inulin (Cin) and p-aminohippurate (CPAH) clearance methods, respectively. RESULTS: In volunteers the mean M-value after Ang II infusion (10.1+/-1.5 mg/kg per min) was significantly higher (P < 0.01) than that after sham infusion (8.2+/-0.9 mg/kg per min). In contrast, in diabetic patients it was not significantly different with Ang II (6.1+/-1.3 mg/kg per min) and sham infusion (5.5+/-1.2 mg/kg per min). The difference in the mean absolute increase in the M value (deltaM) between groups was significant (P< 0.02). The Ang II-induced increase in MBF under euglycaemic conditions was attenuated in diabetic patients (from 15.0+/-3.5 to 15.5+/-3.9 ml/100 ml per min, NS) compared with volunteers (from 16.8+/-3.3 to 19.1+/-3.7 ml/100 ml per min, P< 0.01). Again, the difference between the mean absolute increases in MBF (deltaMBF) in the groups was significant (P < 0.01). A significant correlation was found between deltaMBF and deltaM (r= 0.62, P<0.01). The absolute acute increase in mean arterial blood pressure with Ang II was similar in diabetic patients and volunteers. Mean Cin, CPAH and fractional sodium excretion values were significantly lower and renal vascular resistances and filtration fractions higher during the Ang II than they were during the placebo clamp period. This was observed in patients as well as in healthy subjects, but the effects of Ang II on renal haemodynamics and sodium handling were more pronounced in diabetic patients. CONCLUSIONS: In patients with NIDDM of recent onset the stimulatory effect of Ang II on insulin sensitivity and on skeletal muscle blood flow is attenuated. In contrast, the effects of Ang II on renal perfusion and sodium handling are more pronounced in patients with NIDDM than they are in healthy subjects.

Adult↗
PubMed1997

Influence of acetate and bicarbonate hemodialysis on the plasma erythropoietin concentration in patients with chronic renal failure.

The present study aimed to assess the influence of acetate (AC) and bicarbonate (BI) hemodialysis with a cuprophane membrane on plasma erythropoietin (EPO) levels in 30 patients with chronic renal failure (CRF). Fifteen patients were severely anemic with an Hct below 30%, while 13 were moderately anemic with an Hct equal to or more than 30%. None had received rHuEPO or ACE inhibitors before the study. Blood samples for EPO and pO2 estimation were withdrawn before and after 1, 2 and 5 h of AC dialysis. In 11 of the patients with an Hct < 30% the same protocol was repeated during BI dialysis. In spite of a significant decrease in pO2 during the first hour of AC dialysis, the plasma EPO concentration decreased significantly in both severely and moderately anemic CRF patients from 35.4 +/- 2.6 to 23.6 +/- 3.5 mU/ml after 5 h of hemodialysis (p = 0.0001 by paired t-test) and from 39.5 +/- 8.6 to 27.5 +/- 8.9 mU/ml (p < 0.01) respectively. In contrast to AC dialysis, Bi dialysis failed to change the plasma EPO concentration (from 32.3 +/- 4.1 to 30.3 +/- 4.7 mU/ml after 5 h of hemodialysis). Conclusions AC but not BI hemodialysis shows a significant suppressive effect on plasma EPO levels in anemic CRF patients in spite of a significant decline in pO2. Factors other than pO2 seem to be involved in the regulation of EPO secretion in CRF patients during AC dialysis.

Acetates↗
PubMed1997

[Lipoprotein (a) in physiological states and kidney diseases].

The present paper is a concise summary of contemporary knowledge of lipoprotein(a). Increased lipoprotein(a) concentration is an independent risk factor for atherogenesis. The treatment of choice of increased lipoprotein(a) concentration is causal--for example treatment of the nephrotic syndrome or renal transplantation. If this is not amenable, careful monitoring and elimination of additional risk factors of atherogenesis are mandatory.

Coronary Artery Disease↗
PubMed1996

[Erectile dysfunction in patients with diabetes].

Erectile dysfunction is present in approximately 50% of diabetic men. It is most often caused by diabetic neuropathy and angiopathy but psychogenic factors are also of importance. Treatment includes: elimination of risk factors, psychotherapy, pharmacologic treatment and implantation of penile prosthesis.

Diabetic Angiopathies↗
PubMed1996

[Half-time of erythropoietin in patients with chronic obstructive pulmonary diseases].

Presence of elevated plasma levels of erythropoietin (EPO) has been reported both in polycythaemic and normocythaemic patients with chronic obstructive pulmonary disease (COPD). The present study aimed to elucidate in what extent prolonged erythropoietin half-life time (T1/2EPO) is involved in the pathogenesis of elevated plasma EPO levels in patients with COPD. Seven normocythaemic patients (5 men and 2 women) with CODP and 6 healthy controls (4 males and 2 females) were examined. In all examined subjects half-life time of erythropoietin was determined after i.v. administration of EPO in a dose of 50 U/kg b.m. In COPD patients the T1/2EPO value was 5.98 +/- 0.67 hours and did not differ from that found in healthy controls (5.87 +/- 0.35 h). Results obtained in this study suggest participation of factors other than prolonged half-time of erythropoietin in the pathogenesis of polycythaemia in patients with COPD.

Erythropoietin↗