Maternal cocaine abuse and fetal renal arteries: a morphometric study.

The purpose of the present study was to evaluate the pathological findings and perform morphometric analysis of the renal arteries of fetuses exposed to cocaine in utero. The control group consisted of 22 stillborn fetuses of unknown etiology whose mothers' urine was negative for cocaine or any other vasoactive substances. The study group comprised 29 stillborn fetuses whose mothers' urine was positive only for cocaine on the day of admission. Sections of fetal kidneys (4 microm), stained with hematoxylin and eosin and periodic acid-Schiff reagent, were examined under light microscopy (x40) to identify interlobular arteries. Morphometric analysis of these arteries was performed using a self-assembled system with a touch-sensitive screen as an interactive peripheral. Their inner and outer circumferences were measured by outlining them on the screen with a stylus. The radius (r) was calculated from the measurement of the circumference (2.pi.r). The difference of the radii of the outer and inner circumferences was the thickness of the arterial wall. The interlobular arterial thickness was significantly greater (P<0.001) in the cocaine-exposed group (mean 15.46+/-5.8 microm, 2SD) compared with the normal (mean 9.03+/-3.96 microm, 2SD). There was a significantly (P<0.001) positive relation with advancing gestational ages in both groups. The circumferences of the lumen of the arteries showed a significant (P<0.05) relation with advancing gestational ages in the normal group only. In the cocaine-exposed group, the arterial lumen circumference (mean 167.88+/-17.58 microm, 2SD) was significantly (P<0.001) smaller than in the normal group (mean 227.73+/-6.82 microm, 2SD). Thus, maternal cocaine abuse is associated with thickening of the interlobular arterial wall of the fetal kidney and narrowing of the lumen.

Nephrosis in childhood.

Succinct aspects of clinical features, pathophysiology and prognosis of nephrotic syndrome in childhood, and indications for performing renal biopsy are enumerated in this review. Orthodox treatment of the nephrotic syndrome with more recent therapeutic approaches, and the role of diuretics, albumin infusions and immunizations in patients with the nephrotic syndrome are reviewed. The etiology of peritonitis, acute renal failure, and renal transplantation are re-examined to update nephrologists on the associated complications of this common childhood disease.

Passively mode-locked fiber laser based on polarization rotation in a multiple-quantum-well waveguide.

We give experimental evidence for a new type of mode-locking mechanism for Er-doped fiber lasers based on polarization evolution in an intracavity multiple-quantum-well waveguide. Experiments indicate that anisotropic properties of waveguides can continuously start the mode-locking process.

Emission buildup in Q-switched fiber lasers.

Amplified spontaneous emission is experimentally found to play an important role in the dynamics of pulse formation in Q-switched fiber lasers and leads to stepwise (or quantized) behavior of the emission buildup. This effect could be included in detailed modeling of pulsed fiber lasers and might be interesting in some applications.

Laser transition characterization by spectral and thermal dependences of the transient oscillations.

Spectroscopic measurements on (4)F(3/2) - (4)I(11/2) and (4)F(3/2) - (4)I(9/2) transitions for a Nd(3+)-doped fiber laser demonstrated that the wavelength dependence of the relaxation oscillations provides a simple method to distinguish threeand four-level transition. Spectral analysis of relaxation oscillations in a tunable Er(3+)-doped fiber laser was performed at liquid-nitrogen temperature, and results were compared with measurements at room temperature. It was found that the relaxation oscillation frequency depends on the occupation of the terminal level and thus is directly related to the absorption cross section. Using this method, we show that laser transitions at lambda > 1555 nm become four-level at T = 77K.

Hyperlipidemia in childhood nephrotic syndrome.

Hyperlipidemia is an important characteristic of nephrotic syndrome (NS). Elevation of plasma total cholesterol, or more specifically low-density lipoprotein cholesterol, is the major lipid abnormality in NS, although hypertriglyceridemia may develop as the disorder progresses. The pathophysiology of nephrotic hyperlipidemia is complex. The prevailing view is that both hepatic synthesis of lipids and of apolipoproteins is increased, and that the clearance of chylomicrons and very low-density lipoproteins is reduced. The precise contribution of increased lipogenesis and decreased lipid catabolism to hyperlipidemia, and their relationship to urinary protein loss, hypoalbuminemia and reduced serum oncotic pressure remain controversial. There are two potential risks of elevated plasma lipids: atherosclerosis and progression of glomerular injury. Although neither of these complications has been proved with certainty, there is growing evidence that both may be long-term consequences of NS. Therefore, the diagnosis and treatment of lipid abnormalities, important aspects of the management of nephrotic children, is summarized here to provide pediatric nephrologists with an informed choice.

Intravenous immunoglobulin in minimal change nephrotic syndrome: a crossover trial.

To determine whether intravenous immunoglobulin (IVGG) would be an efficacious adjunct in the treatment of childhood minimal change nephrotic syndrome (MCNS), we enrolled ten patients with frequently relapsing or steroid-dependent MCNS in a double-blind crossover clinical trial. At the time of relapse of the nephrotic syndrome, patients were assigned to treatment with a single outpatient infusion of IVGG (800 mg/kg) or intravenous albumin as a control. The relapse was treated concurrently with standard doses of oral prednisone. At the time of the next relapse, patients who had first received IVGG were treated with albumin, and vice versa. There were no significant differences in the length of remission between the IVGG and albumin treatments. The study had a power of 0.72 to detect a true difference of 45 days between the two therapies. We conclude that in the dose of drug used in this trial, administered at the time of relapse in conjunction with prednisone therapy to children with frequently relapsing or steroid-dependent MCNS, IVGG does not lead to a clinically important extension of the period of remission.

Calcium-activated potassium channels in human platelets.

The cationic fluorescent probe, DiSC3(5) was used to measure the membrane potential in human platelets. Hyperpolarization was induced by the addition of Ca2+ to the medium and also by the addition of the Ca2+ ionophore, A23187. In the absence of extracellular Ca2+ ([Ca2+]o) there was no response to A23187. The threshold concentration for [Ca2+]o was 20 microM and for A23187 was 12 nM. The increase polarity induced by [Ca2+]o was not affected by various K+ channel blockers. However, the effect of A23187 was inhibited by quinine and charybdotoxin, while apamin, tetraethylammonium, and the calmodulin inhibitors trifluoperazine and compound R24571 were ineffective. The resting membrane potential was -66 +/- 0.9 mV and was decreased by quinine. There are three conclusions from this study: (i) Ca2+-activated K+ channels exist in human platelets; (ii) they are the type that are apamin insensitive, charybdotoxin sensitive; and (iii) they may contribute to the resting membrane potential.

Renal histology of mucocutaneous lymph node syndrome (Kawasaki disease).

Renal involvement is well described in patients with mucocutaneous lymph node syndrome (MCLNS), or Kawasaki disease and is manifested by mild azotemia, hematuria, pyuria or cylinduria, and more often, proteinuria. Renal morphology during the acute stages of the illness has never been reported. In this paper we describe the renal histopathologic changes in a child with MCLNS. The glomerular histopathologic findings suggest immune complex damage to the kidney as a possible mechanism of nephrotoxicity in MCLNS. Presence of kidney lesions, which speak in favor of the injurious role of immune complexes in MLCNS may be relevant to the understanding of the pathogenesis of the vascular lesions that are characteristic of this disease.

Limb growth and cardiac complications of fistulas in children.

To assess the long term effects of arteriovenous (AV) fistulas placed in children for hemodialysis, we retrospectively evaluated 26 patients, ages 4 to 20 years, for: limb growth, evidence of excessive flow through the fistula, limb function and patient acceptance of the limb's appearance. The fistulas were created an average of 31 months prior to the study. Fourteen patients had wrist fistulas. Twelve patients had PTFE grafts; 5 in the upper thigh and 7 in the upper arm. Of the 5 patients with thigh PTFE fistulas, 3 developed ipsilateral limb hypertrophy, another developed cardiac failure and the other had excessive flow through the fistula without cardiac failure. One of the 7 children with an upper arm PTFE graft developed arm edema without hypertrophy. Two of the 14 children with wrist fistulas developed evidence of excessive flow through the fistula. Six of 26 patients (23%) required fistula ligation because of a complication.

Hemolytic uremic syndrome followed by acute lymphocytic leukemia.

A 4 6/12-year-old boy presented with severe hemolytic uremic syndrome (HUS) and then developed acute lymphocytic leukemia (ALL) 8 months later. Although other syndromes of hematopoietic dysfunction have been reported to precede the overt and classic findings of leukemia, this report describes a patient who developed ALL preceded by HUS, association not previously described.

Urinothorax: report of 4 cases and review of the literature.

Urinothorax should be considered when pleural effusion occurs in patients with urinary tract obstruction accompanied by retroperitoneal urinoma. This recommendation is based on our experience with 4 cases and a review of the literature. In 2 patients urinary obstruction was owing to retroperitoneal fibrosis secondary to malignancy, including one who had a neuroectodermal undifferentiated small round cell tumor and the other who had a metastatic epithelial neoplasm. In the 2 other patients urinary obstruction resulted from a failed ureteroneocystotomy following renal allograft transplantation. All 4 patients had a urinoma, which may be a predisposing factor to urinothorax.

Accelerated recovery from immune-mediated thrombocytopenia with plasmapheresis.

Autoimmune thrombocytopenia unresponsive to corticosteroid therapy developed in a 16-year-old female with long-standing Sjögren's syndrome. Serial plasma exchange caused a linear decrease in platelet antibody titer associated with a concomitant rise in platelet count. Statistical analysis of sequential platelet counts revealed an increase with plasmapheresis and immunosuppression that was significantly greater than that achieved with immunosuppression alone (p less than 0.005).

Nephritis associated with an infected peritoneovenous LeVeen shunt.

A patient with chronic active hepatitis and medically unmanageable ascites developed staphylococcal bacteremia after insertion of a peritoneovenous LeVeen shunt. The patient developed glomerulonephritis, manifested by moderate proteinuria, microscopic hematuria with red cell casts, azotemia, and evidence of complement activation. The protracted infection, urinary, and renal abnormalities subsided after removal of the LeVeen shunt and a 3-week course of antibiotics. The clinical course of this patient is typical of the immune-complex mediated glomerulonephritis that has been previously well described in hydrocephalic patients with chronically infected ventriculoatrial shunts.

Hematuria after renal allograft biopsy: treatment with aminocaproic acid.

Aminocaproic acid (EACA) was used in 2 patients with cadaveric renal allografts because gross hematuria developed after percutaneous renal biopsies. Marked improvement was noted within twelve hours with no recurrence after discontinuation of EACA. EACA was effective in moderate renal failure.