Biomedical subjects

Gastón Zilleruelo

Publications and source records attributed to Gastón Zilleruelo.

9 recordsLinked to original sources

PubMed2006

Paricalcitol versus calcitriol treatment for hyperparathyroidism in pediatric hemodialysis patients.

Secondary hyperparathyroidism (SHPT) remains a treatment dilemma in pediatric dialysis patients. Recent experience with paricalcitol (P), a vitamin D analogue, in adults with SHPT has shown equal efficacy and improved survival compared to traditional treatment with calcitriol (C). We present our experience with (C) compared to (P) treatment in our pediatric dialysis patients with SHPT. Twenty-one patients (mean age 11.5+/-5 years) with SHPT (intact parathyroid hormone (iPTH) averaging 1,228+/-496 pg/ml) were studied. Seventeen received (C) followed by (P); while an additional four were treated with either (C=1) or (P=3) alone. After 26+/-8 weeks, average percent (%) decrease in iPTH was similar with (C) and (P) (-60.4+/-34% versus -65.4+/-28%, respectively; p=0.6). In the (P) group, the effective dose in children was greater than in adult trials based on kilogram weight. Episodes of hypercalcemia between the treatment groups were not different. However, episodes of elevated calcium x phosphorus product (CaxP)> or =70 mg(2)/dl(2) occurred more frequently in the (C) group (odds ratio=1.5; p=0.01). Paricalcitol appears to be safe and effective in pediatric patients. Data suggest that dosing should be gauged according to degree of SHPT. This should serve as impetus for future pharmacokinetic studies in pediatric dialysis patients.

Adolescent↗

PubMed2006

Profiling proteinuria in pediatric patients.

This study was designed to characterize proteinuria in children with kidney disease. Random urine samples from 250 pediatric patients were examined by quantitative measures of total protein (pr), albumin (Alb), and creatinine (cr). Patient diagnoses were subjectively categorized as "Glomerular" (GD) or "Tubulo-interstitial" disease (TD) in origin. Proteinuria was quantitated by the random urine protein-to-creatinine (Upr/cr) ratio, and glomerular proteinuria was assessed as the albumin-to-creatinine ratio (Ualb/cr) and percentage albuminuria (%Alb=Alb/pr*100). The non-albumin fraction (1-Alb/pr) includes low-molecular-weight proteins and micro- and macroglobulins. Of the 250 patients, 112 (45%) had GD and 138 (55%) had TD. Both proteinuria and albuminuria correlated with a decline in glomerular filtration rate (GFR) (r=-0.4; p<0.0001). Those with GD averaged significantly greater %Alb than those with TD at all levels of proteinuria (p<0.0001). With loss in GFR, %Alb increased significantly in patients with TD (18+/-13 to 47+/-30%; p<0.001) and GD (56+/-26 to 74+/-15%; p<0.01), respectively. The %Alb at all levels of GFR averaged <50% in those with TD and >50% in those with GD. In conclusion, random Ualb/cr, Upr/cr, and %Alb provide a simple and inexpensive assessment of proteinuria and may profile renal disease activity and response to therapy in pediatric patients.

Adolescent↗

PubMed2005

Comparative renal histomorphometry: a case study of oligonephropathy of prematurity.

Children born with very low birth weight have a decreased nephron number. Low nephron mass is associated with adult hypertension, proteinuria, and diabetes mellitus. The histomorphometry and radial glomerular count (RGC) of a total nephrectomy from a child with renal disease associated with extreme prematurity was compared with the kidney from a full-term age-matched child of normal gestation with chronic renal failure due to focal and segmental glomerulosclerosis (FSGS) and to a child without renal disease. Bowman's space area, mesangium and mesangial tuft area were determined in 50 glomeruli of each specimen by computer-assisted morphometry. RGC was 4 in the ex-preterm child, 8 in the patient with FSGS, and 9 in normal control. The patient with FSGS had larger glomerular area expressed as square micrometers (mum(2)) of Bowman's capsule, the mesangium and the mesangial tuft area measurements than the normal control and the child born preterm who subsequently developed renal failure had significantly larger Bowman's capsule and mesangium than the two controls. This case report begins to identify important pathologic findings of decreased nephron numbers and glomerulomegaly associated with preterm birth.

Case-Control Studies↗

PubMed2005

Renal manifestations of sexually transmitted diseases: sexually transmitted diseases and the kidney.

The adolescent population is particularly vulnerable to STDs. Those that cause significant kidney disease are of viral origin. The primary VVD are HIV-1, HBV, and HCV. Screening of high-risk populations should include quantitation of proteinuria, including total protein and microalbumin, to assess severity of renal damage and potential for progression. Renal biopsy is indicated for diagnosis and for planning important treatment interventions if there is significant proteinuria or decreased renal function. Causes of acute renal failure are frequently reversible and should be treated aggressively. These include HUS, vaso-motor or ischemic acute tubular necrosis, and drug toxicities. The spectrum of chronic kidney disease associated with VVD is broad and may include systemic manifestations of vasculitis. HIV-associated nephropathy is the prototype, with the most prevalent lesion remaining FSGS. Progression occurs in up to 15% of the patients, who are overwhelmingly of African lineage. Significant advances in management include ongoing development of HAART, angiotensin antagonists to control proteinuria, and novel immune-modulating drugs such as MMF, CsA, and rituximab. Dialysis therapies have offered improved survival, especially in pediatric patients. Moreover, transplantation is no longer considered experimental and should be offered to select patients.

Adolescent↗

PubMed2004

Recurrent focal glomerulosclerosis in pediatric renal allografts: the Miami experience.

Recurrence of focal glomerulosclerosis (FSGS) following renal transplantation is a common cause of allograft loss and clinical morbidity. Recent attempts to control proteinuria and morbidity with plasmapheresis (PP) have met with limited success. Our experience with the use of mycophenolate mofetil (MMF) and angiotensin blockade (AB) in the management of refractory FSGS pre transplant suggested its potential benefit in post-transplant recurrence. This report presents our 25-year experience in pediatric renal transplantation of patients with FSGS divided into two treatment eras: Era 1-prior to use of daclizumab (anti-IL-2R) and Era 2-after daclizumab. A total of 179 pediatric patients were transplanted during the 25-year period. FSGS was confirmed in 27 (15%); 16 of 28 allografts (57%) had recurrence of FSGS during the post-transplant period. In Era 1, only 6 of 16 (38%) recurred in the allograft, while 10 of 12 (83%) recurred during Era 2. The odds ratio of recurrence of FSGS in the allograft after induction with anti-IL-2R was 8.3 (95% confidence interval=1.3-52, P =0.02). Only 2 patients in Era 1 received PP, while 10 in Era 2 were entered into an intensive PP protocol followed by maintenance with AB consisting of angiotensin receptor blockers alone, or in combination with angiotensin-converting enzyme inhibitor. Although proteinuria decreased an average of 80+/-16% with PP, the response was variable and severe morbid edema persisted in poor responders. Maximum benefit occurred with the addition of AB and MMF. After a follow-up of 27+/-15 months, proteinuria has shown a sustained decrease of 94+/-8% below baseline. In conclusion, our experience suggests that, with recurrent FSGS, a limited course of PP followed by maintenance therapy with AB and MMF improves symptoms and may preserve allograft function.

Adolescent↗

PubMed2004

A functional immature model of chronic partial ureteral obstruction.

BACKGROUND: The most common nonlethal congenital anomaly of the urinary tract is ureteral obstruction without dysplasia. Although rarely progressive, the morbidity associated with metabolic and surgical management is considerable. Our study was designed to measure local and systemic pathophysiologic mechanisms in an immature model of chronic partial unilateral ureteral obstruction (UUO) after completion of glomerulogenesis. METHODS: A partial UUO was created by the method of "psoas wrap" in young male weanling rats. Control animals were sham operated. Three groups were divided as follows: sham (N= 15), UUO (N= 18), and UUO + angiotensin-converting enzyme (ACE) (N= 16) inhibitor, enalapril. Renal glomerular and tubular functions were determined by creatinine and uric acid clearances. Diuresis was assessed by urine volume, osmolality, and fractional solute excretions from samples above and below the obstruction. Proteinuria was determined by the urine protein/creatinine ratio (Up/c). RESULTS: Proteinuria was attenuated in UUO + ACE-treated animals. The hyperuricemia of the immature UUO animals was avoided by an increase in the clearance of uric acid in the UUO + ACE-treated group. Fractional solute excretions suggested a diversion of diuresis to the contralateral unobstructed kidney. CONCLUSION: Angiotensin blockade during chronic UUO in young rats affords protection by attenuating proteinuria, promoting uricosuria, and diverting solute diuresis. These data suggest a complex interaction of local and systemic mechanisms unique to the maturing kidney.

Animals↗

PubMed2003

Long-term follow-up of extremely low birth weight infants with neonatal renal failure.

The long-term outcome of 20 preterm infants with extremely low birth weight and acute renal failure in the neonatal period was studied retrospectively over an 18-year period. Those with progressive renal disease are compared with those with normal renal function. Current mean age is 7.5+/-4.6 years (range 3.2-18.5 years). Nine patients showed deterioration in renal function (low GFR group). Increasing proteinuria, as determined by random urine protein/creatinine ratio (Up/c), correlated with deterioration in renal function ( r=0.8, P<0.0001). Prominent risk factors for progression were Up/c >0.6 at 1 year of age [100% sensitivity, 75% positive predictive value (PPV), P<0.01], serum creatinine >0.6 mg/dl at 1 year of age (75% sensitivity, 80% PPV, P<0.01), and a tendency to obesity with body mass index >85th percentile (89% sensitivity, PPV 67%, P=0.03). Loss of renal mass and nephrocalcinosis were not prognostic indicators. This report begins to identify important clinical parameters that should lead to closer surveillance and potential treatment interventions for preservation of renal function in a growing population of surviving low birth weight individuals.

Acute Kidney Injury↗

PubMed2003

Novel therapy of focal glomerulosclerosis with mycophenolate and angiotensin blockade.

Steroid-resistant nephrotic syndrome of childhood poses a dilemma in attempting to balance toxicity of medications against long-term prognosis. This report presents our preliminary experience with the novel use of combined mycophenolate mofetil (MMF) and angiotensin blockade (AB) in the treatment of nine children and young adults with focal glomerulosclerosis (FSGS). All patients were steroid resistant and had failed conventional treatment regimens. Prior to the initiation of the MMF-AB protocol, the patients were pre-treated with weekly intravenous methylprednisolone (MP) (15 mg/kg per week) for 4-8 weeks. Angiotensin-converting-enzyme inhibitors and/or angiotensin receptor blockers were begun when intravascular volume was restored. MMF was given at a dose of 250-500 mg/m(2) per day. Proteinuria, as measured by urine protein/creatinine ratios (Up/c), decreased by 43% following MP ( P<0.05). After 6 months of MMF-AB protocol, the Up/c was 72% below baseline ( P<0.01). This level was maintained for a minimum of 24 months of observation. Similarly, hyperlipidemia, as measured by total cholesterol and triglycerides, improved significantly with treatment (536+/-163 to 265+/-70 mg/dl, 447+/-168 to 230+/-92 mg/dl, respectively, P<0.01). Our data support the use of MMF and AB for treatment of steroid-resistant FSGS when other conventional treatments have failed and/or induced toxicity.

Adolescent↗

PubMedDate not supplied

Role of routine urinalysis in asymptomatic pediatric patients.

This study was done to evaluate the spectrum of diagnoses and identify risk factors for significant kidney disease in asymptomatic children with proteinuria and/or microhematuria detected by routine urinalysis. Clinical and laboratory data were obtained by retrospective chart review of 239 patients referred to a tertiary care center. The predominant diagnosis in children with isolated microhematuria was hypercalciuria and with isolated proteinuria, orthostatic proteinuria. When microhematuria and proteinuria were present in combination, kidney disease was the predominant diagnosis. Urinalysis is a valuable tool to identify patients with kidney disease. The combination of microhematuria and proteinuria increases the risk of having significant kidney disease.

Child↗