Ahmet Erbagci

Pediatric urolithiasis--evaluation of risk factors in 95 children.

Objective: Pediatric urolithiasis is a rarely encountered pathology, except in endemic areas such as Turkey. As a recurrent pathology which may reveal functional as well and morphologic changes in the urinary tract, metabolic and environmental factors, in addition to urogenital abnormalities, should be evaluated thoroughly in each patient. In this prospective study, the patient and family histories of 95 children with stone disease were evaluated, together with serum and urine risk factors. Material and Methods: Between 1996 and 2001, 95 children (25 females, 70 males; mean age 7.3 years; age range 0.6-15 years) referred to our department with urolithiasis were evaluated. All patients were investigated with respect to stone localization, associated abnormalities, urinary tract infection (UTI), positive family history and serum and urine risk factors. In addition to standard risk factors (hypocitraturia, hypercalciuria, hyperoxaluria, hyperuricosuria, hypomagnesuria), diet and 24-h urine volume were also assessed in all children. Children with cystinuria were excluded from the study. Results: Stone size ranged from 0.3 to 3.3 r cm, with an average value of 2.0 r cm. The localization of the stones was classified as unilateral single stone in 37 patients, multiple unilateral stones in six and bilateral multiple stones in 27. Hypocitraturia was the commonest risk factor detected in our patients. A positive family history was present in 51 cases (54%). In addition, UTI was present in 59 cases (62%) and 67 cases had a previous history of recurrent UTI. Associated urogenital abnormality was detected in nine cases (9.4%). There were significant correlations between stone size and urinary citrate excretion ( p r < r 0.05) and between the presence of UTI and urinary phosphate excretion ( r r = r 0.59, p r = r 0.047). Treatments used were open surgery in seven (7.3%) cases, extracorporeal shock-wave lithotripsy in 39 (41%) and endoscopic surgery in 20 (21%). Following these procedures, 39 (41%) patients were completely stone-free, 11 (11%) had residual stones (<5 r mm in diameter) and 12 (14.8%) passed the stone(s) spontaneously. During follow-up, regrowth was seen in four (4.2%) patients and stone recurrence was noted in a further four (4.2%). Conclusions: In addition to stone removal, treatment of pediatric urolithiasis requires a thorough metabolic and environmental evaluation of all patients on an individual basis. Obstructive pathologies have to be corrected immediately and apparent metabolic abnormalities should also be treated. Children with a positive family history should be followed carefully with respect to stone recurrence. Urine volume increases in parallel with body mass index and medical therapeutic agents which increase urine citrate levels should be encouraged.

Serum prolidase activity as a marker of osteoporosis in type 2 diabetes mellitus.

OBJECTIVES Prolidase is a specific imidodipeptidase involved in collagen degradation. The increase in the enzyme activity is believed to be correlated with the increased intensity of collagen degradation This study aimed to evaluate serum prolidase activity and urinary deoxypyridinoline cross links in type 2 diabetic subjects with and without osteoporosis assessed by bone mineral density. DESIGN AND METHODS Seventy-five patients (54 F/21 M) with type 2 DM and 43 age and gender matched healthy subjects (30 F/13 M) were recruited for this study. Serum prolidase activity was assessed with colorimetric determination. Urinary deoxypyridinoline (Dpy) was determined with electrochemiluminesence immunoassay. RESULTS Serum prolidase activity was significantly lower in patients with type 2 DM than in the healthy controls (mean +/- SEM; 43.3 +/- 1.4 U/L and 53.3 +/- 2.2 U/L respectively, p: 0.000). Non osteoporotic diabetic patients had lower serum prolidase activity (median: 25th-75th percentiles; 39.5: 30.3-50.5 U/L) than osteoporotic diabetic patients (50.0: 41.8-56.3 U/L, p: 0.030) and healthy controls (52.0: 43.0-58.0 U/L, p: 0.004). Urinary Dpy excretion was not different between osteoporotic and nonosteoporotic diabetic patients. However it was lower in both diabetic groups than the healthy controls. We did not observe a statistically significant difference between the serum prolidase activity of dislipidemic/normolipidemic, hypertensive/normotensive, obese/nonobese, insulin/OAD treated, poorly/well-controlled patients and patients with/without diabetic nephropathy and retinopathy (p > 0.05). CONCLUSION This study shows a significant decrease in serum prolidase activity in patients affected with type 2 DM, which may be interpreted as evidence of decreased bone resorption. Our data also suggest that serum prolidase activity may be a better marker of osteoporosis in diabetic state than Dpy.

Renal tubular injury induced by hyperoxaluria: evaluation of apoptotic changes.

Abstract In order to evaluate the injurious effect of hyperoxaluria on renal tubular epithelium, as judged by apoptotic changes in the renal parenchyma, we performed an experimental study in 20 rabbits. In the experimental group animals (n=10) severe hyperoxaluria was induced by continuous ethylene glycol (EG; 0.75%). Histologic alterations, including crystal formation, together with apoptotic changes were evaluated after 7 and 28 days. Control group animals (n=10) received normal distilled drinking water. Following 7- and 28-day periods, tissue sections obtained from kidneys were examined histopathologically under light microscopy for the presence and the degree of crystal deposition in the tubular lumen. Apoptotic changes in renal tubular cells were examined using the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP in situ nick and labeling (TUNEL) method during the same follow-up period. Crystal deposition was evident in the tubular lumen of tissue sections obtained during the 7-day examination period. During the 28-day examination period, however, these findings were found to be either limited or to have disappeared. In relation to apoptotic changes, the percentage of positive nuclei stained using the TUNEL method was from 11 to 20% in the experimental group and 5.6% in the control group. Our findings indicate that both calcium oxalate (CaOx) crystals and hyperoxaluria itself may be injurious to renal tubular cells, as indicated by apoptotic changes. These changes may be responsible for the pathologic course of urolithiasis.

Unilateral Testicular Torsion: Protective Effect of Verapamil on Contralateral Testicular Histology

In this experimental study, it was our aim to reduce the effects of ischemic insults to the contralateral testicle after unilateral testicular torsion. The protective effect of a calcium channel blocking agent (verapamil) on the histology and the tubular diameter of contralateral testicle was evaluated. Following a definite period of unilateral testicular torsion (i.e., 4 h), the protective effect of this specific medication was evaluated both after detorsion and orchiectomy procedures. The results of our study demonstrated the protective effect of verapamil on both parameters, especially in animals undergoing orchiectomy. The majority of the specimens demonstrated normal histologic findings together with preserved tubular structures after a 1-week period under verapamil medication.

Multidisciplinary evaluation of occult spinal dysraphism in 47 children

Objective: To present the clinical (urologic, orthopedic and neurologic) and urodynamic findings of 47 children suffering from occult spinal dysraphism, together with the long-term follow-up results obtained with various treatment modalities. Material and Methods: Between 1997 and 2000 a total of 47 children (27 girls, 20 boys; male:female ratio 1.3) referred to the Urology and/or Pediatrics Departments with symptoms and signs of closed spina bifida were enrolled in the study program. All patients underwent routine assessment of the urinary tract, including detailed anamnesis, physical examination and radiologic evaluation (X-ray, renal bladder ultrasonography and sacral MRI). In addition to video-urodynamic evaluation of the lower urinary tract, all patients were also evaluated by the Orthopedic Department with respect to possible lower extremity deformities. Results: The age range of the children was 2 months to 16 years (mean 6.9 years). At first referral, 23 children were found to have normal urinary and fecal continence after toilet training; among the other presenting symptoms and signs, 34% of patients demonstrated recurrent urinary tract infections and 38.2% had abnormal findings on urinary tract investigations. Evaluation of urodynamic parameters before and after conservative treatment demonstrated an increase in age-related bladder capacity in 34 patients and detrussor instability had been cured in 23/30 patients (p < 0.05). Overall, bladder capacity was found to be normal in 40 children following conservative management (p < 0.05). The conservative approach proved to be effective in 40 children (85.1%), and intravesical instillation therapy with oxybutynine hydrochloride was successful in one of the remaining seven children (14.2%). Bladder augmentation was performed in six children (12.7%) in whom conservative measures were ineffective. Conclusions: In the light of our findings and the literature data it is obvious that a multidisciplinary approach together with early urologic evaluation to determine the extent of neurologic involvement of the lower urinary tract is essential to ensure a successful treatment outcome and to prevent the occurrence of serious functional and structural complications. Clinical, radiologic and video-urodynamic assessments should be performed to define the neuro-urologic pathophysiology and to provide management guidelines and a baseline for future comparison.

Evaluation and Therapeutic Regulation of Erectile Dysfunction with Visual Stimulation Test

Aim: An objective evaluation of the psychogenic cause of erectile dysfunction by performing the visual stimulation tumescence and rigidity (VSTR) test and sildenafil citrate test, together with the effectiveness of sildenafil citrate medication on impotence caused by different etiologies. Material and Methods: Between 1998 and 2000, a total of 36 men (12 patients with diabetic etiology, 5 patients with vasculogenic risk factor) were enrolled in this study. The mean age of patients was 53 (27–67) years. Following standard questionnaires, including a detailed anamnesis from an andrologic viewpoint, VST was performed in an ambulatory setting and beginning with a test dose of 50 mg. At the end of 2 h, the data was evaluated with computer assistance (Rigiscan device) and if a satisfactory erection had not occurred, an additional second dose of sildenafil citrate (50 mg) was given until there was a satisfactory erection. Results obtained from VST: results were classified as group I (fully rigidity, >10 min erection, >70% of rigidity, possible vaginal penetration), group II (unstable erection, 5 min erection, >70% of rigidity, possible vaginal penetration) and group III (tumescence without rigidity, <5 min erection, <70% of rigidity, impossible vaginal penetration). The results obtained during the first 1 h of the VSTR test were regarded as the patient’s own erectile condition and later data was accepted as the real effect of sildenafil citrate. The Fisher exact test was used for statistical evaluation including pre- and post-sildenafil effect on erectile rigidity and duration of erection. Results: The erection status of patients was sufficient in 17 (47.2%) in group I, it was insufficient but sufficient enough with an increased dose of sildenafil citrate in 10 (27.7%) in group II, and insufficient without/with full dose of sildenafil citrate in 9 (25%) in group III. Considering rigidity and total erectile period, there was a statistical significant difference between the first two groups with respect to the early and late sildenafil citrate effects on the VSTR test (p < 0.05). Again, 10 patients with known risk factors (diabetes mellitus 5 and vasculogenic 5) in the second group seemed to give a good response to repeated dosage of sildenafil citrate which has been found to be very interesting. However, the rest of the diabetic patients (n = 7) in the third group showed no erection despite the increasing and repeated doses of sildenafil citrate. Conclusion: Sildenafil citrate with the VSTR test has effective and reliable results which was regarded as very important to diagnose and determine objectively the amount of therapeutic doses in impotence. In accordance with the literature data, our results also confirm the reliability and the practical nature of the VSTR test, which is less time-consuming and cheaper than the nocturnal penile tumescence and rigidity (NPTR) test. In the VSTR test, necessary doses of medication needed for satisfactory erection were easily regulated in patients with certain kinds of impotence. Additionally, self-criticism advantage of the patients on erection and an unnecessary need for regular sexual partners may make this test preferable in the near future. However, we believe that a large group of patients with other definite parameters are certainly needed in order to obtain more reliable data.

Predictive value of renal histological changes for postoperative renal function improvement in children with congenital ureteropelvic junction stenosis

Background: The aim of this study was to evaluate the relationship between renal function, as measured by diuretic radionuclide renography, and the outcome of pyeloplasty. A study was designed to evaluate renal parenchymal biopsy specimens derived from children undergoing corrective surgery for ureteropelvic junction (UPJ) stenosis, and compare these to preoperative and postoperative renal function status.

Verapamil prevents the apoptotic and hemodynamic changes in response to unilateral ureteral obstruction.

Introduction:  Obstruction of the urinary tract has marked effects on renal blood flow, glomerular filtration rate (GFR), and tubular function. Moreover, ureteral obstruction results in an injury response that can progress to irreversible renal fibrosis and tubular atrophy by apoptosis.

Reflex Anuria After Renal Tumor Embolization

We report a case of reflex anuria after transarterial embolization of a renal tumor. Anuria developed immediately after embolization and resolved 74 hr following the procedure. We postulate that reflux anuria in our case was related to mechanoreceptors, chemoreceptors, or both, as these are stimulated by the occluded blood vessels, ischemia, and edema of the normal renal tissue of an embolized kidney.

The place of diuretic enhanced Doppler sonography in distinguishing between obstructive and non-obstructive hydronephrosis in children.

OBJECTIVE In an attempt to differentiate obstructive from non-obstructive dilation of the renal collecting system in children, a prospective clinical study was carried out. MATERIAL AND METHODS During duplex Doppler sonography examination in 23 children resistive index (RI) and pulsatility index (PI) and RI ratio values before and after intraverous furasemide administration were compared with the findings obtained with diuretic renogram examination (t(1/2)). RESULTS Evaluation of the results demonstrated that diuresis RI and PI determination may aid differentiation of severely obstructed renal units from those with slight (equivocal) or no obstruction. CONCLUSION Kidneys with severe UPJ obstruction tended to have more elevated RI and PI values than the non-obstructed or equivocally obstructed ones. Again, determination of RIR values for each kidney showed the same elevation in severely obstructed kidneys, while non-obstructive or indeterminately obstructed ones demonstrated statistically insignificant changes.