Determination of renal function in long-term heart transplant patients by measurement of urinary retinol-binding protein levels

Significant improvements have been noted in heart transplantation with the advent of cyclosporine. However, cyclosporine use is associated with significant side effects, such as chronic renal failure. We were interested in evaluating the incidence of long-term renal dysfunction in heart transplant recipients. Fifty-three heart transplant recipients were enrolled in the study. Forty-three patients completed the entire evaluation and follow-up. Glomerular (serum creatinine, creatinine clearance measured, and creatinine clearance calculated) and tubular functions (urinary retinol-binding protein, uRBP) were re-analyzed after 18 months. At the enrollment time, the prevalence of renal failure ranged from 37.7 to 54 percent according to criteria used to define it (serum creatinine > or = 1.5 mg/dL and creatinine clearance <60 mL/min). Mean serum creatinine was 1.61 ± 1.31 mg/dL (range 0.7 to 9.8 mg/dL) and calculated and measured creatinine clearances were 67.7 ± 25.9 and 61.18 ± 25.04 mL min-1 (1.73 m²)-1, respectively. Sixteen of the 43 patients who completed the follow-up (37.2 percent) had tubular dysfunction detected by increased levels of uRBP (median 1.06, 0.412-6.396 mg/dL). Eleven of the 16 patients (68.7 percent) with elevated uRBP had poorer renal function after 18 months of follow-up, compared with only eight of the 27 patients (29.6 percent) with normal uRBP (RR = 3.47, P = 0.0095). Interestingly, cyclosporine trough levels were not different between patients with or without tubular and glomerular dysfunction. Renal function impairment is common after heart transplantation. Tubular dysfunction, assessed by uRBP, correlates with a worsening of glomerular filtration and can be a useful tool for early detection of renal dysfunction.

Early detection of renal disease in occupational hydrocarbon exposure by using non Invasive biomarkers

Early detection of renal dysfunction resulting from exposure to a nephrotoxin is important since this is the first step in the progressive loss of renal functions and ultimately progression to renal failure which are characteristic of the nephrotoxic cascade. Using modem technology, minute quantities of LMWP and urinary enzymes can be measured. Excretory patterns that are characteristic for site and mechanism of renal injury often can be found. This study was carried out to investigate the link between the occupational hydrocarbon exposure and nephrotoxicity by using the non invasive urinary markers for early detection of subclinical reversible conditions. Twenty adult men works as paint sprayer [chronic exposure] composing the first group and compared them to twenty adult males with a minimal exposure matched age, weight, height, blood pressure and residential ares, composing the second group as a control group. The results showed a significant increase in B2-microglobulin [B2 mic] p<0.003, Retinol binding protein [RBP] p<0.001, N-acetyl-B-D-glucosaminidas [NAG] p<0.0001 in the first group as compared to the normal control group. Serum creatinine shows no difference between the two groups, As a conclusion, by using non invasive methods our results are in keeping with the hypothesis that hydrocarbon exposure through paint spraying may result in active proximal tubular damage which may be reduced by improvement of protection at their work site as heavy duty overalls, thick gloves and more important air-fed mask for the airway and face protection. Follow up studies are necessary to assess the prognostic value of early changes detected in workers chronically exposed to organic solvents

Determinación de microproteínas urinarias en orinas sin concentrar / Urinary low molecular weight proteins on unconcentrated urine

Se realizó la determinación cuali y cuantitativa de las microproteínas urinarias (MU): Alfa-1 microglobulina (A1m), proteína transportadora del retinol (RBP) y Beta-2 microglobulina (B2m), en 138 orinas de 24 h de recolección con pH superiores o iguales a 5.5, en pacientes adultos con distintos cuadros uroproteicos: 38 fisiólogicos, 59 glomerulares, 19 tubulares y 22 mixtos. Se describe la metodología analítica para optimizar la detección de las MU mediante la técnica de electroinmunofijación (EIF) con coloración argéntica, en orinas sin concentrar. El rango de sensibilidad para las distintas MU fue de 3-100mg/l. La cantidad de antisuero monoespecífico empleado por cm2 de gel fue: anti-A1m (4µl/cm2), anti-RBP (4µl/cm2) y antiB2m (2µl/cm2). La determinación cuantitativa se relizó por inmunodifusión radial (IDR) para RBP y B2m, y por electroinmunodifusión (EID) para A1m. La detección de MU en orinas sin concentrar mediante esta metodología de alta sensibilidad y la cuantificación de las mismas permitieron efectuar un correcto diagnóstico de proteinuria tubular y mixta superando las eventuales pérdidas o desnaturalización protéica que acarrean los clásicos métodos de concentración. La detección elevada de A1m (15-65 mg/l) en 12 de 59 orinas con proteinuria glomerular, plantea un interrogante sobre la cuantificación aislada de la MU para definir un patrón tubular

Urinary retinol binding protein, albumin, total protein concentrations and blood electrolytes in term and preterm neonates

Fifty neonates were included in this study, divided into two groups. Group 1[control group] consisted of 22 healthy neonates. Group 1A included 12 full term, 3 females and 9 males. Their gestational ages ranged between 37-39 weeks [mean 37.58 +/- 0.76 weeks]. Group 1B included 10 preterm neonates, 4 females and 6 males. Their gestational ages ranged between 28-34 weeks [mean 30.8 +/- 2.44 weeks]. Group II included 28 sick neonates admitted to the neonatal care unit of the pediatric department of El-Menoufiya University hospital and El-Menshawy general hospital. 10 had asphyxia, 5 had pneumonia, 7 had hyaline membrane disease and 6 had acute hemolysis. All the neonates were under antibiotic therapy. Group IIA consisted of 14 full term neonates, 2 females and 12 males. Their gestational ages ranged between 37-40 weeks [mean 37.64 +/- 0.81 weeks]. Group IIB consisted of 14 preterm neonates, 3 females and 11 males. Their gestational ages ranged between 27-35 weeks [mean 30.5 +/- 2.44 weeks]. All the neonates were subjected to thorough clinical history and examination, as well as measurement of serum sodium and potassium, blood urea, serum creatinine, urinary creatinine, total protein excretion, and measurement of urinary excretion of microalbumin and retinol binding protein [RBP] in untimed urine samples by ELIZA technique. The blood urea, microalbuminuria and total proteins were significantly elevated in sick neonates [Group II] compared to healthy neonates [Group I], however the difference was not influenced by the gestational age. No significant difference could be detected in serum sodium, potassium, serum creatinine and urinary creatinine between both groups. Measurement of RBP revealed that the healthy preterm neonates [Group IB] had a significantly higher level of RBP compared to the healthy full term [Group IA, P <0.05]. Also, the sick neonates [Group II] had a significantly higher level compared to the healthy ones [Group I, P<0.01]. RBP showed a significant negative correlation with the gestational age and the Apgar score at 1 and 5 minutes, and a significant positive correlation with blood urea and microalbuminuria. Evaluating the renal function by the excretion of RBP and microalbuminuria, showed that RBP was positive in 84% of the cases while microalbuminuria was detected in 30% of the cases only. It can be concluded that Retinol binding protein is an early and specific non-invasive marker of tubular functions. It has the advantage of being able to unmask even subtle cases of kidney injury when other parameters of kidney functions are still within the normal range