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Biomedical subjects

V Stefanović

Publications and source records attributed to V Stefanović.

At least 19 recordsLinked to original sources

Effects of physical exercise in patients with end stage renal failure, on dialysis and renal transplantation: current status and recommendations.

There is increasing evidence about the benefits of regular physical activity in the chronically ill. Patients with chronic renal failure prior to and after renal transplant are one of the target groups in which increased controlled physical activity is highly recommended. Significant atrophy and increased non-contractile tissue are present in the muscle of predialytic and patients on hemodialysis, which is associated with poor physical performance and poor outcome of renal disease. Thus, interventions to increase physical activity or otherwise address atrophy may improve performance and quality of life in these patients. Other abnormalities in these patients, such as metabolic impairments, anemia, and hormonal changes, especially insulin resistance and lipid disorders, could be also modulated by certain therapeutic agents and physical activity. Increasing activity levels in this target group could be particularly important since it is well established that controlled physical exercise reduces the risk of cardiovascular disease in the general population. Patients who participate in regular physical activity following transplant will have higher health-related fitness and quality of life compared to those who remain inactive. The potential risk of physical activity can be reduced by medical evaluation, risk stratification, careful supervision, and education.

Exercise↗

Treatment of insulin resistance in uremia.

Insulin resistance is a characteristic feature of uremia. As long as the hyperinsulinemia adequate to overcome the insulin resistance, glucose tolerance remains normal. In patients destined to develop type 2 diabetes, the beta cell compensatory response declines, and relative, or absolute, insulin deficiency develops. At this point glucose intolerance and eventually frank type 2 diabetes occur. Insulin resistance and concomitant hyperinsulinemia are present irrespective of the type of renal disease. Several studies have confirmed that hemodialysis (HD) treatment significantly improves insulin resistance. Both CAPD and CCPD are shown to improve insulin resistance in uremic patients. Comparing the effect of PD and HD treatment, it was found that the CCPD group has significantly higher insulin sensitivity than the HD group with the CAPD group similar to HD. Treatment of calcium and phosphate disturbances, including vitamin D therapy, significantly reduces insulin resistance in uremia. Treatment with recombinant human erythropoietin (EPO) is an efficient way to increase hematocrit, to reverse cardiovascular problems and to improve insulin sensitivity. Angiotensin-converting enzyme inhibitors have been shown to improve insulin resistance, hyperinsulinemia and glucose intolerance in uremic patients. Thiazolidinediones (TZDs), the new insulin-sensitizing drugs, provide the proof that pharmacologic treatment of insulin resistance can be of enormous clinical benefit. The great potential of insulin resistance therapy illuminated by the TZDs will continue to catalyze research in this area directed toward the discovery of new insulin-sensitizing agents that work through other mechanisms.

Anemia↗

Urinary PC-1 and N-acetyl-beta-D-glucosaminidase activity in patients with type 2 diabetes treated with metformin, gliclazide or glibenclamide.

BACKGROUND: Insulin resistance is a key feature of type 2 diabetes mellitus. Plasma cell differentiation antigen (PC-1) is an inhibitor of insulin receptor tyrosine kinase, and has been implicated in the pathogenesis of insulin resistance. METHODS: Urinary excretion of PC-1 was determined in 45 newly detected, obese diabetic patients treated with metformin (16 patients), gliclazide (14 patients) or glibenclamide (15 patients). Urinary N-acetyl-beta-D-glucosaminidase (NAGA), a lysosomal enzyme, was determined as a marker of tubular damage in diabetes. RESULTS: Basal urinary PC-1 excretion in all three groups of diabetic patients was at the level of healthy controls. Treatment with oral hypoglycaemic drugs did not change significantly the group level or the number of patients in each group with increased PC-1 activity. Urinary excretion of NAGA in patients with type 2 diabetes was not statistically different from the control level. Metformin and gliclazide treatment did not change significantly the group levels of NAGA excretion. However, glibenclamide treatment produced an increased urinary NAGA excretion in the whole group, and in about twice as many patients as in the pre-treatment period.

Acetylglucosaminidase↗

Urinary PC-1 activity in patients with type 1 diabetes mellitus.

BACKGROUND: Insulin resistance characterizes type 1 diabetes mellitus with nephropathy. The molecular mechanisms of insulin resistance are not completely understood. Recently some advances have been made in identification of transmembrane glycoprotein PC-1 as a potential factor of insulin resistance. METHODS: We measured urinary excretion of PC-1 (alkaline phosphodiesterase I), a potential factor of insulin resistance, and N-acetyl-beta-D-glucosaminidase (NAGA) in 62 type 1 diabetic patients with different damage to the kidney. RESULTS: In newly detected type 1 diabetes patients, before insulin therapy, urine PC-1 excretion was significantly increased (P<0.05) over the control level. However, in patients after 12.4 years of therapy, urinary PC-1 was significantly decreased (P<0.05). Decreased urine PC-1 activity (P<0.05) was found also in type 1 diabetes patients with microalbuminuria and manifest nephropathy, including those with renal failure. Urinary NAGA excretion was found to be significantly increased (P=0.001) in all but the group of type 1 diabetes patients without nephropathy. CONCLUSION: This study of urinary PC-1 in patients with type 1 diabetes shows increased excretion in newly detected patients with poor glycaemic control, but decreased excretion in patients with micro-/macroalbuminuria as well as in those without apparent kidney damage. In patients with primary glomerulonephritis, urinary excretion of PC-1 was significantly decreased and that of NAGA significantly increased compared with the excretion in healthy controls.

Acetylglucosaminidase↗

Long-term functional outcome of kidneys in children with urolithiasis after ESWL treatment.

The aim of this study was to determine the long-term functional outcome of kidneys in children with urolithiasis treated by means of extracorporeal shock wave lithotripsy (ESWL). The effectiveness and safety of this method in the management of pediatric urinary stone disease was also studied. This prospective study enrolled 84 children, 33 boys (age: 9.1 +/- 3.8 yrs) and 51 girls (age: 9.6 +/- 3.9 yrs), with urolithiasis who were treated using a second-generation "Siemens" Lithostar lithotriptor, in the period between 1988 and 1998. Dynamic kidney scintigraphy using (99 m)Tc-DTPA was done prior to, immediately following ESWL treatment, three months later, and again after an observation period of 12 - 67 months (38 +/- 13 months). Immediate fragmentation rate was 90 %, while the calculus clearance rate was 61 %. Glomerular filtration rate (GFR), measured by clearance of (99 m)Tc-DTPA, immediately after an ESWL treatment of 107 +/- 6 ml/min was significantly lower compared to the pretreatment value of 118 +/- 7 ml/min, but returned three months later to 121 +/- 6 ml/min, and to 131 +/- 10 ml/min at the end of the observation period. A separate analysis was performed on three groups of patients treated by ESWL: with acute calculous disease, chronic calculous disease, and chronic calculous with partial stasis. ESWL treatment in children with acute obstruction was associated with an immediate increase in GFR; however, in chronic calculous disease a decrease in GFR was found. A return of GFR to the pretreatment level was observed at the three-month control in these patients. In patients with acute stone obstruction, at 3 and 12 - 67 months after ESWL treatment, GFR of the treated kidney was found to be significantly increased compared to the pretreatment level. In contrast, in children with chronic calculous disease this increase was modest. This study has demonstrated ESWL to be an effective treatment option for urinary calculi management, which can be safely performed in a pediatric population without long-term effects on the growing kidneys.

Acute Disease↗

Combined treatment of immobilization staghorn stones in 14-year old boy.

We report a combined urologic treatment of bilateral staghorn stones, developed in a boy after prolonged immobilization for limb fractures. He underwent percutaneous nephrostolithotomy (PCNL) on the left side, and after three months pyelolithotomy and nephrolithotomy for stasis in the right kidney, followed by ESWL for residual calculus in the left ureter. He becomes stone free, with apparently normal kidney function.

Bed Rest↗

Extracorporeal shock wave lithotripsy monotherapy of 'stoned' internal ureteral stent in children. Case report.

A case of ESWL treatment, as monotherapy, of a 'stoned' ureteral stent in a 12-year-old boy was described. Two years previously, the patient had pyelolithotomy with staghorn stone removal, and double-J stent was left indwelling intraoperatively. The patient was lost for follow-up for 2 years, when he had multiple stone formation adherent to the whole length of the stent. Four ESWL sessions were required before the stent was freed for removal.

Child↗

Effect of adequacy of dialysis and nutrition on morbidity and working rehabilitation of patients treated by maintenance hemodialysis.

Numerous studies have demonstrated a correlation between adequacy of hemodialysis (HD) and patient mortality. In this study we evaluated the effect of adequacy of dialysis and nutrition on morbidity and working rehabilitation. Single center experience carried out in 1998 in an outpatient university-affiliated dialysis facility was presented. A total of 181 patients, on HD over 3 months, was included in the study; mean age 54.5 years, mean duration of HD 5.4 years. Thirty-two patients were hospitalized in 1998. Patients with an eKt/V < 0.8 had significantly more frequent and extended hospitalizations than patients with eKt/V > 1.2. In the regression model eKt/V had a significant effect on hospital days. Serum albumin, as an index of nutrition, was also found to significantly influence hospitalizations. Patients with a BMI < 20.0 kg/m2 were found to have significantly more frequent hospitalizations, more hospital days/patient, and hospital days/hospitalized patient/year than those with a BMI > 25.0 kg/m2. BMI < 20.0 kg/m2 was associated with a significantly lower dialysis adequacy (eKt/V and URR) and more severe anemia. However, regression model failed to confirm a statistically significant association of BMI with hospital days. The best working rehabilitation (stage 1), according to the EDTA criteria, was obtained in patients with significantly (p<0.05) higher eKt/V, URR, albumin, nPNA, and body fat than in patients at stage 6 (not able to work, and not able to take care of themselves). This study has established that dialysis adequacy and nutrition have an effect on morbidity (estimated through hospitalizations) and patient rehabilitation.

Adolescent↗

Prevention of nosocomial transmission of hepatitis C infection in a hemodialysis unit. A prospective study.

Hepatitis C virus (HCV) infection in hemodialysis patients can be transmitted by transfusions and nosocomially. A high prevalence of HCV infection, over 50%, was demonstrated in our hemodialysis (HD) unit. In order to prevent the nosocomial spread of HCV infection in the HD unit a prospective study was begun separating anti-HCV positive patients from the negative ones. A total of 170 patients (83 anti-HCV positive) started this study in September 1994 and were followed for 4 years. A separate room and dedicated equipment were assigned to anti-HCV positive and anti-HCV negative patients. Of those 170 patients there were 15 hepatitis B virus (HBV) positive patients, 5 of whom were anti-HCV positive, who were treated in a separate room on dialysis equipment for anti-HCV positive or negative patients. Application of general precautions, as recommended by the Center for Disease Control and Prevention (CDC), was reinforced. During the first 12 weeks after implementing the precautions seven more anti-HCV positive patients were detected, and by December 1995 another two HCV infected patients were found. The follow-up included all changes in HD population treated until the end of 1998. The incidence of seroconversion to HCV was 12.9% in 1995, 7.1% in 1996, 5.0% in 1997, and 6.6% in 1998. The higher incidence of seroconversion in September to November 1994 was probably due to the nosocomial infection being in the incubation period at the time of isolation. This prospective study in a large HD unit with a high prevalence of HCV infection demonstrates a relatively successful prevention of HCV spread. Procedure-related transmission of HCV in hemodialysis could be prevented by rigorous application of universal precautions as recommended by the CDC. As a second line of prevention, in highly burdened dialysis centers, segregation of HCV positive patients can help control nosocomial transmission.

Adult↗

Radionuclide voiding pattern in children with unstable bladder.

BACKGROUND: The purpose of this study was to investigate bladder function parameters by means of quantitative radionuclide cystography (QRC) in anxious, irritable children with unstable bladder. METHODS: Quantitative radionuclide cystography was performed in 18 children aged between 8 and 12 years, without evidence of neurologic and nephrologic disorders. Findings were compared with those obtained in 10 healthy children aged between 7 and 10 years. The dynamics of the bladder emptying were studied after intravenous injection of 37 MBq/10 kg b.w. 99mTc-diethylenetriaminepentaacetic acid (DTPA) in the posterior views. Images of 90 frames every 2 sec. were stored in the 64 x 64 computer matrix during voiding. The patients voided into a container and the volumes were measured. RESULTS: The parameters evaluated were: functional bladder capacity (ml)--FBC, expected bladder capacity (ml)--EBC, percentage of EBC (%), voided urine volume (ml)--VV, residual urine (ml)--RU, voiding time (sec)--VT, average flow rate (ml/sec)--AFR and peak flow rate (ml/sec)--PFR. There was a statistically significant difference between controls and children with unstable bladder in the following parameters: FBC 288 +/- 33 vs. 244 +/- 27 ml (p < 0.001), % of EBC 99 +/- 6 vs. 82 +/- 6% (p < 0.0001), VV 265 +/- 37 vs. 202 +/- 35 ml (p < 0.0001), RU 22 +/- 11 vs. 48 +/- 19 ml (p < 0.007), AFR 13 +/- 5 ml/sec vs. 9 +/- 4 ml/sec. (p < 0.01) and PFR 19 +/- 2 vs. 13 +/- 3 ml/s (p < 0.0001), respectively. The VT obtained from the control group of 23 +/- 9 s did not differ significantly from the value of children with unstable bladder of 28 +/- 14 s. CONCLUSION: The results show that quantitative radionuclide cystography is a simple, noninvasive method, which allows a good separation of patients with unstable bladder from the children with normal voiding pattern.

Journal Article↗

Tissue polypeptide antigen and carcinoembryonic antigen lack diagnostic accuracy in urothelial carcinoma.

Carcinoembryonic antigen (CEA) and tissue polypeptide antigen (TPA) levels in serum and urine from 25 patients with bladder cancer and 42 patients with cancer of the renal pelvis/ureter have been evaluated as an aid for clinical diagnosis of urothelial cancer. The tumour CEA content varied markedly, from values obtained in normal urothelium up to 822 and 7306 ng/g wet tissue in cancer of the renal pelvis/ureter and bladder cancer, respectively. Serum and urine CEA levels were found not to correlate with the tumour CEA content. Serum CEA levels were found increased over 5 microg/L in up to 16% of bladder cancer patients, but only in 4.8% in renal pelvis/ureter cancer. Urine of cancer patients contained usually normal CEA levels. Increased serum TPA levels were found in 48% and 35.7% of patients with bladder cancer and cancer of renal pelvis/ureter, respectively. Urine TPA levels were significantly increased in both, patients with bladder cancer (p<0.001) and cancer of renal pelvis/ureter (p<0.01). The median values of urine TPA were 59, 1095 and 1325 U/L, in controls, patients with bladder cancer and cancer of renal pelvis/ureter, respectively. However, considering previously described increase of TPA in inflammatory diseases of urinary tract and in renal failure patients, results of urinary TPA obtained in the diagnostic workup of urothelial cancer should be cautiously interpreted. This study shows that serum and urine levels of CEA and TPA have no diagnostic accuracy required for clinical diagnosis of urothelial cancer.

Carcinoembryonic Antigen↗

Acute effects of acetaminophen on renal function and urinary excretion of some proteins and enzymes in patients with kidney disease.

The acute effects of acetaminophen, a commonly used as analgesic drug, upon the urinary excretion of some proteins and enzymes as markers of kidney damage, was investigated. Patients with chronic glomerulonephritis (GN) and Balkan endemic nephropathy (BEN), having kidney vulnerable to toxic drugs, were enrolled in the study. Timed urine specimens were collected: before drug administration, and in 3-hour periods for 24 hours after an oral dose of 2 g of acetaminophen. Urinary excretion of albumin before acetaminophen treatment was significantly higher in patients with GN and BEN than in healthy adults, however, beta 2-microglobulin excretion was increased in BEN patients only. Urinary excretion of creatinine markedly increased immediately after acetaminophen ingestion. Urinary excretion of total protein and albumin was not changed after acetaminophen administration. However, acetaminophen treatment produced a significant increase in beta 2-microglobulin excretion in patient with BEN and GN, and in clinically healthy members of nephropathic families. Excretion of aminopeptidase N (APN) activity before acetaminophen treatment was significantly higher in patients with GN, however, NAGA excretion was higher in both GN and BEN patients than in healthy controls. After acetaminophen administration urinary excretion of APN, dipeptidylpeptidase IV (DPP IV), gamma-glutamyltranspeptidase (GGT) and N-acetyl-beta-D-glucosaminidase (NAGA) did not increase significantly in any group studied. This study has shown that urinary excretion of APN, DPP IV, NAGA and GGT, as markers of kidney brush border and lysosomal damage, did not change after 2 g of acetaminophen taken orally. beta 2-microglobulin was a marker of acute acetaminophen nephrotoxicity in kidney disease patients and in clinically healthy adults from nephropathic families.

Acetaminophen↗

Elevated tumour markers in patients with Balkan endemic nephropathy.

Balkan nephropathy (BEN) is commonly associated with urothelial cancer. Urothelial cancer is manifested in the advanced stage of disease. The aim of this study was to facilitate early detection of urothelial cancer in BEN patients and their family members living in an endemic region by using tumour markers, carcinoembryonic antigen (CEA) and tissue polypeptide antigen (TPA), and a putative marker, ferritin. Fifteen BEN patients with normal renal function, 17 with renal failure (BEN-RF), 13 healthy members of their families (HFM), 14 patients with glomerulonephritis (GN) and 12 healthy controls (C) were studied. Serum CEA levels in BEN patients were within normal limits, however, in BEN-RF patients they were significantly increased over HFM (p<0.05). Serum TPA levels in BEN and BEN-RF patients were significantly higher than in the C and HFM groups (p<0.05). Urinary CEA was not significantly different between the groups studied. Urinary TPA levels in HFM (median 125 U/l, BEN (236 U/l) and BEN-RF (275 U/l) were significantly increased over C (30 U/l), however, TPA levels were increased also in GN patients (437 U/l). None of the BEN patients studied developed urothelial cancer during the ten years' follow-up. Markedly elevated urinary TPA-like levels in all patients studied (HFM, BEN, BEN-RF, GN) suggest that urinary TPA may not be a reliable tumour marker. However, the clinical relevance of high TPA levels in BEN patients should be evaluated.

Balkan Nephropathy↗