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% 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%) 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%) with elevated uRBP had poorer renal function after 18 months of follow-up, compared with only eight of the 27 patients (29.6%) 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.

The role of catecholamines in the distribution of intrarenal blood flow and in single-nephron glomerular filtration rate (SNGFR) was evaluated in anesthetized Wistar rats by the Hanssen technique. Epinephrine (EPI) and norepinephrine (NOR) were infused to produce elevations of 20-30 mmHg in mean arterial pressure. Superficial and juxtamedullary nephron perfusion and filtration were determined by the presence of Prussian blue dye. In the control group, 100% of the nephrons presented a homogeneous pattern of perfusion and filtration. In contrast, a heterogeneous distribution of the dye was found even in the larger arteries (arciform and radial), indicating variable perfusion and filtration in both superficial and juxtamedullary nephrons. The effects of EPI and NOR were also evaluated in the superficial cortex by the micropuncture technique in two additional groups of Munich-Wistar rats. Mean SNGFR was 27% and 54% lower in the EPI- and NOR-treated groups, respectively. No change in mean intraglomerular hydraulic pressure was observed after EPI or NOR infusion in spite of a highly scattered pattern, indicating an important variability in perfusion along the superficial cortex, and/or different sensitivity of the pre- and post-glomerular arterioles. The present data suggest that EPI and NOR may affect intrarenal hemodynamics by modifying perfusion and filtration in both superficial and juxtamedullary glomeruli and not by shifting blood flow from superficial to juxtamedullary nephrons. The heterogeneous pattern of perfusion was a consequence of differential vasoconstriction along the intrarenal arteries, probably due to different density and/or sensitivity of the adrenergic receptor subtypes present in the intrarenal vascular tree.

A produtividade final da cana-de-açúcar, dentre outros fatores de produção, é afetada pela distância entre linhas de plantio. O rendimento potencial é obtido, para cada genótipo considerado, sob condições ideais de clima e solo, estando as plantas dispostas em espaçamentos ideais. Diversos experimentos revelaram haver aumento de produtividade agrícola da cana-de-açúcar com a utilização de menores espaçamentos entre sulcos. O presente estudo foi conduzido em estações experimentais de 5 municípios (Araras/SP, Pirassununga/SP, Pradopólis/SP, Rubiácia/SP e Cristalina/GO), sujeitos às variações de clima, tipo de solo, espaçamento e material genético empregados, e teve por objetivo analisar o comportamento da espécie, em termos de produção agrícola, e propor equações de incremento ou depleção da produção potencial como função do espaçamento adotado.

The final productivity of sugar cane, among other yield factors, is affected by the distance between the row of plants. The potential production is obtained, for each genotype considered, under ideal edapho-climatic condictions, being the plants placed in ideal spacings. Several experiments present increases of the agricultural productivity of sugar cane with the use of narrower spacings between rows of plants. The present survey was performed at experimental stations of five districts (Araras/SP, Pirassununga/SP, Pradopólis/SP, Rubiácia/SP and Cristalina/GO), presenting variations in climate, soil, spacing and genetic material studied, with the objective of analysing the behaviour of the species, in agricultural production terms, and to propose equations to estimative the potential production as a function of the spacing to be adopted.