Search PubMed⌕ Search

Biomedical subjects

J Stríbrná

Publications and source records attributed to J Stríbrná.

At least 19 recordsLinked to original sources
PubMed2000

Evaluating the outcome of percutaneous transluminal angioplasty in renal graft artery stenosis using the areas under the time curve of glomerular filtration rate and blood pressure.

The benefit of percutaneous transluminal angioplasty (PTA) of transplant renal artery stenosis for ischemic nephropathy may be adversely affected by rejection or other complications. As a result, assessment of the effect of PTA on renal function or blood pressure is often difficult. In this paper, we evaluated the effect of PTA using the method of integrated glomerular filtration rate (GFR) based upon the area under the curve over a follow-up period (AUC0-1), to express the level of GFR in a simple manner despite its significant fluctuations. A similar procedure was used to evaluate mean arterial pressure (MAP). The method was employed to assess the outcome in 20 individuals before PTA, and 1, 3, 6, 9 and 12 months after PTA. In eight cases, rejection was detected while there was one case of glomerulonephritis in the graft during the follow-up period. Evaluation (AUCCcr)0-12 related to the integrated pre-PTA value of Ccr [(Ccr)0 x 12] revealed a rise in GFR by more than 20 % in 65 % of cases. No improvement was observed in seven individuals with post-PTA complications. When assessing the integrated value of MAP, success of PTA (a reduction by at least 10 %) was found in 85 % of cases. No significant correlation was found between the relative changes of integrated GFR and MAP. Our data suggest that evaluation of the integrated value of GFR or MAP on the basis of AUC0-t allows to characterize, in a simple manner, the level of graft function and MAP throughout the follow-up period in individual cases. Furthermore, it may provide additional information on the average values obtained at different time intervals after the therapeutic procedure.

Adult↗
PubMed1999

[Evaluation of the results of percutaneous transluminal angioplasty of arterial stenosis in the transplanted kidney using area under time curves of the glomerular filtration rate and blood pressure].

The benefit of percutaneous transluminal angioplasty (PTA) of renal transplant artery stenosis for renal hemodynamics is frequently adversely affected by rejection or another complication. As a result, evaluation of the effect of PTA is often difficult. Our study was designed to assess the effect of PTA using a method of integrated value of the glomerular filtration rate (GFR) calculated on the basis of the area under the curve over the follow-up period (AUC0-t). A similar procedure was employed to evaluate mean arterial pressure (MAP). The method was used to assess the outcome in 20 individuals before to PTA, and at 1, 3, 6, 9 and 12 months after angioplasty. A rejection episode was diagnosed in eight cases and glomerulonephritis of the graft in one. Using the evaluation of (AUCCcr)0-12 in relation to the integrated value before PTA (Ccr) x 12, a rise in GFR > 20% was found in 65% of cases. PTA failure was observed in seven individuals developing post-PTA complications. When assessing the integrated value of MAP, PTA was found to be successful (a reduction by at least 10%) in 85% of cases. No significant correlation was demonstrated between the integrated values of GFR and MAP. The results support the assumption that the evaluation of the integrated values of GFR or MAP using AUC0-t allows to characterize, in a simple manner, the degree of renal transplant function or MAP throughout the follow-up period, and to furnish additional information to the values obtained at individual time intervals after the therapeutic procedure.

Adult↗
PubMed1999

[Renovascular hypertension].

UNLABELLED: Renovascular disease frequently escapes clinical diagnosis. Critical stenosis of the renal artery causes hypoperfusion of the kidney which in turn is the cause of renovascular hypertension and ischaemic nephropathy. Detection of renovascular disease in the population of hypertonic patients should be based on clinical symptoms. In a selected group one of the imaging methods can be used. The increasing number of patients with stenosis of the renal artery is indicated for percutaneous transluminal angioplasty or surgical revascularization as the function of the ischaemized kidney is a risk. Medicamentous treatment of hypertension, which is usually successful, is indicated in patients with atherosclerosis with a history of cardiovascular complications or a high risk of the latter. The contribution and risk of different therapeutic methods must be considered individually with regard to the clinical condition as well as the findings on the blood vessels. CONCLUSION: A unique contribution of angioplasty in stenosis of the renal artery or surgical revascularization is the possibility to improve renal haemodynamics and thus renal function. Prevention of ischaemic nephropathy calls for early diagnosis of renovascular disease.

Humans↗
PubMed1998

Long-term follow-up of the tubular secretion of creatinine in renal graft recipients.

The differences in glomerular filtration rate (GFR) based on creatinine clearance (Ccr) or obtained by the more exact methods are caused mainly by tubular creatinine secretion. In this study, we monitored creatinine clearance (Ccr), GFR on the basis of polyfructosan renal clearance (C(PF)) and parameters characterizing tubular creatinine secretion (Ccr/C(PF), Ccr - C(PF), Tcr/C(PF) x 100) in 12 individuals with renal grafts (Group A), 12 kidney graft donors for related transplantation (Group B), and in 27 individuals undergoing nephrectomy for a pathological process in one kidney (Group C). In the monitored groups, C(PF) and Ccr values were within the limits consistent with the normal function of a single kidney in a healthy individual. The values characterizing tubular creatinine secretion in Group A did not differ significantly from those obtained in Groups B and C. However, the parameters showed a wide range in all groups. In seven individuals with a renal graft, all the above functional parameters were monitored at three-month intervals for a period of 24 months. Significant differences in the time courses of Ccr and C(PF) due to marked intra-individual fluctuations were found in tubular creatinine secretion. The findings suggest that the rate of tubular creatinine secretion in the renal graft does not differ significantly from that in individuals with a single native (normally functioning) kidney. However, there are large inter-individual differences. The large intra-individual fluctuations in tubular creatinine secretion in the kidney graft result in significant differences in the time courses of Ccr and C(PF) and a possibility of erroneous evaluation of graft function if based exclusively on Ccr.

Adolescent↗
PubMed1998

[Principles of gene therapy].

Treatment of disease by gene transfer into the genome of target host cells has become possible. This article presents current clinical applications of gene therapy and describes possible corrections of genetic defects.

Genetic Therapy↗
PubMed1998

[Vectors used in gene therapy].

The ability to direct gene transfer to particular target cells is important to achieve a therapeutic effect. In this review we describe the development of methods for gene delivery to specific cell types.

Genetic Therapy↗
PubMed1998

[Renal excretion of potassium in individuals with stabilized function of a transplanted kidney].

From previous work it is known that in subjects with a transplanted kidney treated with cyclosporin A hyperkalaemia may develop even if the glomerular filtration rate is within the normal range or only slightly reduced. The mechanism of this defect was not elucidated so far. In the present work the authors try to study the question whether and how renal potassium excretion by the transplanted kidney is influenced by the intensity of sodium excretion. Focused on renal excretion of potassium, sodium, chlorides, all osmotically active substances, glomerular filtration rate (polyfructosan clearance) and renal plasma flow (paraaminohippuric acid clearance) the authors examined 12 patients after transplantation of the kidney from a cadaverous donor (group A), 11 subjects after unilateral nephrectomy for the purpose of donorship for transplantation (group B) and 27 subjects after nephrectomy on account of a pathological process in one kidney (group C). The glomerular filtration rate in the investigated groups was greater than 1.0 ml/s/1.73 m2. The mean value of the fractional potassium excretion (FEK) in group A was 15.2 (+/- 6.3)%, in group B 18.4 (+/- 6.6)% and in group C 20.1 (+/- 8.6)%. The value of FEK in group A was significantly lower than in group C (p < 0.01). Groups B and C did not differ significantly in the mean value of FEK. Between values of FEK and FENA a significant direct correlation was found (r = 0.621, p < 0.001) in the group of subjects with a single kidney of their own (B + C). On the other hand, this correlation was not found in subjects with a transplanted kidney (A). The achieved results support the idea that in subjects with a transplanted kidney treated with cyclosporin A there are deviations in tubular potassium transport even when its serum level is not elevated. This deviation is manifested by lower FEK values and also by and inadequate response of the distal tubule to an increased sodium supply by increased tubular potassium secretion. The authors assume that when drugs with a potential potassium retaining effect are administered to subjects with a transplanted kidney it is important to check carefully the serum potassium level even when the glomerular filtration rate is within normal limits or only slightly reduced.

Adult↗
PubMed1997

[Renal excretion of sodium in individuals with stabilized renal graft function].

In subjects with a transplanted kidney frequently tubular functions are impaired even when the glomerular filtration is within the normal range. In the present work the authors are dealing in more detail with the problem of tubular sodium reabsorption in the transplanted kidney. The purpose of the investigation was to assess to what extent these changes can be explained as the consequence of adaptational changes due to reduction of the number of nephrons and whether these changes have to be taken into consideration in the differential diagnosis of acute changes of graft function. The glomerular filtration rate (GF) was assessed on the basis of polyfructosan clearance, fractional sodium and potassium excretion (FENa and FEK) in a group of 12 subjects with a stabilized function of a transplanted kidney (group A), in 11 subjects after nephrectomy in healthy donors for transplantation (group B) and in 27 subjects after nephrectomy indicated for a pathological process in one kidney (group C). The mean values of GFR were as follows: Group A: 1.21 (+/- 0.19)ml/s/1.73 sq.m Group B: 1.19 (+/- 0.17)ml/s/1.73 sq.m Group C: 1.24 (+/- 0.21)ml/s/1.73 sq.m The mean values of GFR in different groups did not differ significantly. The mean values of FENa in different groups were as follows: Group A: 3.02 (+/- 1.59)% Group B: 2.05 (+/- 0.77)% Group C: 2.01 (+/- 1.17)% The mean value of FENa in group A was significantly higher than the mean value in group B (p < 0.01) and in group C (p < 0.01). The assembled findings support the idea that reduced tubular sodium reabsorption in the transplanted kidney (with a stabilized value of GFR) cannot be explained only as a manifestation of adaptation of tubular function as a result of the reduced number of functioning nephrons. The persisting osmotic sodium diuresis in the transplanted kidney must be viewed from the aspect of possibly impaired water preservation and the development of dehydration associated with a drop of GFR and must be differentiated from rejection.

Adolescent↗
PubMed1997

[Percutaneous transluminal angioplasty of the renal artery in transplanted kidneys].

UNLABELLED: The objective of the work was to evaluate the contribution of percutaneous transluminal angioplasty (PTA) to treatment of hypertension and the graft function of a transplanted kidney. Angioplasty of the graft artery was performed in 39 patients. Technical success rate: 85%. COMPLICATIONS: 13%--in particular during the first years after introduction of the method. Twenty seven patients were followed up on a long-term basis. Changes of the median arterial pressure (MAP) were evaluated as well as glomerular filtration (GF) assessed by creatinine clearance. Mean values: [table: see text] A statistically significant (p < 0.01) reduction of the median arterial pressure (drop by > 10 mm Hg) along with reduction of the number of antihypertensive drugs was recorded in 70% of the patients during the first year and in 80% kidney recipients in investigations extending beyond one year. A significant increase of glomerular filtration (by > 20%) was found in 40% of the patients, on average the rise was insignificant. During the follow up period 13 kidney recipients were transferred to a dialyzation programme due to failure of the grafts as a result of rejection. CONCLUSION: Percutaneous transluminal angioplasty of a stenosis of the graft artery is the method of first choice in the treatment of hypertension. It is of fundamental importance also in rare cases in order to preserve or improve graft function and thus delay dialyzation treatment.

Adult↗
PubMed1996

Effects of insulin and lipid emulsion on renal haemodynamics and renal sodium handling in IDDM patients.

To evaluate the role of insulin and hypertriglyceridaemia in the regulation of renal haemodynamics and sodium handling in insulin-dependent diabetes mellitus (IDDM), 11 IDDM patients without microalbuminuria and 13 weight-, age-, protein intake- and sex-matched healthy control subjects were studied. Clearances of inulin (Cin), para-amino-hippuric acid (CPAH), sodium (CNa), and lithium (CLi) were measured in four 60-min clearance periods (periods I, II, III and IV) during isoinsulinaemia with lipid emulsion infusion (study 1), a hyperinsulinaemic isoglycaemic clamp with Intralipid infusion (study 2), and during time-controlled isoinsulinaemia (study 3). We found that Cin, CPAH and filtration fraction were comparable in IDDM and control subjects, whereas CNa was decreased in diabetic subjects (2.01 +/- 1.11 vs 3.03 +/- 1.32 ml/min; p < 0.05) due to elevations of proximal tubular fractional and absolute reabsorptions of sodium (p < 0.05). Insulin infusion did not affect Cin, increased CPAH (p < 0.05) and, consequently, lowered the filtration fraction (p < 0.01) in both groups. While acute hyperinsulinaemia resulted in increases in distal tubular fractional and absolute reabsorptions of sodium (p < 0.01) contributing to a fall in CNa (p < 0.01) in control subjects, in diabetic subjects the sodium-retaining effect of insulin was not significant. The lipid emulsion did not alter any of the estimated parameters. We conclude that IDDM without microalbuminuria is associated with a tendency to sodium retention which is not aggravated by insulin when compared to control subjects. Acutely induced hypertriglyceridaemia does not alter renal haemodynamics or renal sodium handling.

Adult↗
PubMed1995

[Renal hemodynamics and albuminuria in patients with arterial hypertension].

BACKGROUND: The cause of hyperalbuminuria in hypertonic patients can be functional or irreversible structural changes. The objective of the present investigation was an attempt to differentiate these two possibilities by comparing data of hypertonic patients with normal albuminuria (albumin excretion < 20 micrograms/min) and those with microalbuminuria in patients with renovascular hypertension by comparing findings after successful percutaneous transluminal angioplasty of the renal arteries (n = 8). METHODS AND RESULTS: The authors examined 20 patients with normal albuminuria (12 men and 8 women, mean age 46 years) and 20 patients with microalbuminuria (12 men and 8 women, mean age 49 years). Of these patients 8 were examined repeatedly after angioplasty. The examination was made in the morning, renal haemodynamics were assessed by the infusion technique (clearance of polyfructosan and paraaminohippuric acid), in blood and urine the albumin and IgG concentration (bromcresol purpur-Lachema Brno and immunoturbidometrically-Tina-quant Boheringer Mannheim). In hypertonic patients with microalbuminuria a significantly higher (p < 0.001) IgG excretion was found (14.1 as compared with 5.12 micrograms/min.) and a reduced ratio of IgG clearance to albumin clearance (p < 0.001), 0.73 as compared with 1.60. After successful angioplasty of the renal arteries there was a significant drop of the blood pressure (p < 0.05) and of the renal vascular resistance as well as a significant decrease of albuminuria (p < 0.05) on average from 137 to 48 micrograms/min. The quantitative improvement of albuminuria, however, did not go beyond the discrimination value for microalbuminuria. CONCLUSIONS: The results suggest that microalbuminuria in hypertensive patients is as a rule a manifestation of structural renal changes, while also functional and reversible changes participate. The asset of treatment of hypertension by angioplasty of the renal arteries was manifested not only in the renal haemodynamics but also by reduced albuminuria.

Albuminuria↗
PubMed1995

Relation of cholesterol esterification rate to the plasma distribution of high-density lipoprotein subclasses in normal and hypertensive women.

We studied the particle size distribution of plasma high-density lipoproteins (HDL) by gradient gel electrophoresis and by assay of cholesterol esterification rate (FERHDL) in plasma depleted of very low (VLDL) and low-density (LDL) lipoproteins in 32 hypertensive women (53 +/- 10 y old) and in an age-matched group of 21 apparently healthy women. There were no significant differences between the groups with respect to their plasma total, HDL- and LDL-cholesterol. The plasma triglyceride (TG) concentration was significantly higher in the group of hypertensive women, and HDL-free cholesterol was significantly lower in the hypertensive group. There were highly significantly differences in the relative proportions of HDL subclasses between the hypertensive and control women: HDL2b was significantly lower and HDL3b,c was significantly higher in hypertensive patients compared to controls. FERHDL was 12 +/- 4%/h in the control group and 18 +/- 6%/h in patients with hypertension (p < 0.001). There was a strong positive correlation between FERHDL and the relative content of HDL3b,c, and a strong negative correlation between FERHDL and HDL2b in both groups. Comparison of subgroups of healthy and hypertension pre- and postmenopausal women revealed, apart from age, no significant differences between the healthy subjects in any of the above parameters.

Adult↗
PubMed1994

Thymidine kinase in malignant melanoma.

Thymidine kinase (EC 2.7.1.21) is an enzyme supporting DNA synthesis under conditions of increased cell proliferation. Although it has proved to be a useful marker for various malignant diseases, it has not been tested in malignant melanoma. Thymidine kinase activity was measured by means of a radioenzymic assay in two classical animal models of melanoma disease--B16 and Cloudman S91 melanoma-bearing mice. Tumour cell proliferation was assessed histochemically by measuring the expression of proliferating cell nuclear antigen (PCNA). Tumour cytosolic specific thymidine kinase activity was found to be higher in less pigmented Cloudman S91 melanoma than in differentiated, ie pigmented B16 melanoma, relative to the proliferative activity of the two tumours. Serum thymidine kinase levels were increased in melanoma-bearing animals of both types compared with healthy mice; this also reflected the efficacy of the therapy: cyclophosphamide-treated B16 melanoma-bearing mice in which the tumour development was slowed down had significantly lower serum enzyme levels in comparison with the non-treated group and the same levels compared with control, healthy mice. Our results suggest that serum thymidine kinase levels might be used as a marker to follow the effect of melanoma therapy.

Animals↗
PubMed1993

[Changes in plasma renin and aldosterone after parathyroidectomy in patients with hyperparathyroidism].

The plasma renin activity and its changes after parathyroidectomy indicate a preserved internal secretory renal function in dialyzed patients. The PRA values before parathyroidectomy are not unequivocally related to the blood pressure reading. After parathyroidectomy during the initial months the renin and aldosterone plasma levels decline in patients with secondary and primary HPT (p < 0.001), the urinary Na/K quotient rises in primary HPT (p < 0.05) and the systemic blood pressure declines in dialyzed patients with secondary HPT (p < 0.001). The findings suggest relations between the two hormonal systems during hyperparathyroidism and in the early stage after parathyroidectomy. Parathormone probably stimulates renin secretion. After a prolonged time interval following operation the parathormone levels in the blood steam reach normal levels and the same probably applies to intracellular calcium in cells of the iuxtaglomerular apparatus along with PRA.

Adult↗
PubMed1993

[Albuminuria after acute oral administration of proteins in patients with renovascular hypertension].

In a group of 19 patients with renovascular hypertension the effect of a morning snack comprising meat (1 g protein per 1 kg body weight) on urinary albumin excretion was assessed. Concurrently the plasma creatinine concentration (Pcr) was examined which varied between normal and 260 mumol/l and the creatinine clearance (Ccr). After administration of an acute protein load the mean Ccr value increased by 23%. The albumin excretion, however, did not change substantially, as compared with the previous collection period (mean 17 and 18 micrograms/min). Microalbuminuria was recorded in 31% of the patients and its prevalence was directly related to the increasing Pcr value. The results revealed that an acute protein load did not increase albuminuria although the rise of Ccr was significant. The variability of albumin excretion in the course of the day is, however, influenced also by other factors and for assessment of microalbuminuria therefore examination of 24-hour urine samples should be preferred.

Adult↗
PubMed1992

[Membrane transport of cations in erythrocytes during treatment of essential hypertension with angiotensin-converting enzyme inhibitors].

The authors investigated in ten patients with essential hypertension changes in the membrane transport of sodium in red blood cells and the intracellular calcium content of thrombocytes during the control period during treatment of hypertension with central sympatholytics and after three-week treatment with an inhibitor of the angiotensin converting enzyme (ACE), enalapril. The effect of enalapril in hypertonic patients was manifested by a rise of the renin plasma activity and the potassium concentration and a reduction of the sodium plasma concentration which corresponds to the inhibition of angiotensin II. The intracellular calcium and sodium content was unaltered. In 8 of 10 patients after enalapril treatment increased values of Vmax for Na(+)-K+ cotransport occurred, incl. 6 patients where at the same time a rise of Vmax Na(+)-Li+ countertransport was recorded.

Adult↗
PubMed1992

Urinary albumin excretion in patients with renovascular hypertension.

Twenty-four hour urinary excretion of albumin (UEalb), IgG and beta-2 microglobulin was investigated at a 3 hour-interval in a control group (C) of healthy subjects, in 30 patients with renovascular hypertension (RVH), and in 16 patients with essential hypertension (EH). Mean UEalb in RVH was significantly higher than in C. A significant direct correlation was demonstrated between diastolic blood pressure and UEalb (p < 0.01). Microalbuminuria (MA) > or = 30 micrograms.min-1 was found in about 18% of RVH patients; it was higher than 16.7 micrograms.min-1 in approx. 31%. These results did not substantially differ from those obtained in patients with EH. The cause for increased UEalb in hypertensive patients may be functional, haemodynamic changes, or structural ones. In either case, MA indicates renal injury, and these patients should be given increased attention when monitoring their blood pressure and when selecting antihypertensive drugs.

Adult↗