Fetal renal maldevelopment with oligohydramnios following maternal use of piroxicam.

A female neonate, born by cesarean section at 37 weeks of gestation, presented with respiratory distress syndrome, right pneumothorax and anuria. A sonogram showed increased echogenicity, with neither hydronephrosis nor macroscopic cysts. Peritoneal dialysis was started on the 14th day because of renal insufficiency, but the newborn died on the 33rd day. Family history was unremarkable, except that the mother received piroxicam at about the 26th week of gestation. A sonogram at the 28th week showed oligohydramnios. Histopathological study of the kidneys revealed crowded glomeruli and only few differentiated proximal convoluted tubules in the inner cortex, abnormally differentiated microcystic tubules and microcystic glomeruli in the outer cortex. Periodic acid-Schiff staining showed only traces of brush border in the dilated tubules of the outer cortex. Immunoperoxidase staining for epithelial membrane antigen was positive in the luminal border of all tubules. Electron microscopy confirmed the presence of brush border remnants and other proximal tubular characteristics in some segments. The renal abnormality bears some similarities to that found in familiar renal tubular dysgenesis, but it fits better with those described after maternal use of angiotensin converting enzyme inhibitors and nonsteroidal anti-inflammatory drugs. The lesion in this case appears to have resulted from fetal exposure to piroxicam. Recently, a second pregnancy ended in a completely normal female newborn.

Determination of zinc in serum, blood, and ultrafiltrate fluid from patients on hemofiltration by graphite furnace/atomic absorption spectroscopy or flow injection analysis/atomic absorption spectroscopy.

Two methods were optimized for the determination of zinc in samples of blood, serum, and ultrafiltrate fluid from patients with chronic renal impairment undergoing hemofiltration. In the first procedure, after acid digestion of the samples, Zn in blood and serum is determined by a system coupled to flow injection analysis and atomic absorption spectroscopy. The method is rapid, automated, simple, needs small amounts of sample, and has acceptable analytical characteristics. The analytical characteristics obtained were as follows: determination range of method, 0.05-2.0 ppm of Zn; precision as coefficient of variation (CV), 5.3%; recovery, 95-105%; and detection limit (DL), 0.02 ppm. The second method is optimized for ultrafiltrate fluid because the sensitivity of the first procedure is not suitable for the levels of Zn (ppb or ng/mL) in these samples. The technique chosen was atomic absorption spectroscopy with electrothermal atomization in a graphite furnace. The analytical characteristics obtained were as follows: determination range of method, 0.3-2.0 ppb Zn; CV, 5.7%; recovery, 93-107%; and DL, 0.12 ppb. The methods were used to determine zinc in samples of blood, serum, and ultrafiltrate fluid from 5 patients with chronic renal impairment undergoing hemofiltration to discover whether there were significant differences in the zinc contents of blood, serum, and ultrafiltrate fluid after the hemofiltration process. An analysis of variance of the experimental data obtained from a randomly selected group of 5 patients showed that zinc concentrations in the ultrafiltrate fluid, venous blood, and venous serum do not vary during hemofiltration (p < 0.05), whereas in arterial blood and serum, the time factor has a significant effect.

Indirect determination of the pesticide dimethoxydithiophosphate in an FIA-AAS system with liquid-liquid back-extraction.

A method has been developed for the determination of dimethoxydithiophosphate (DDTP) by liquid-liquid extraction in a flow-injection analysis (FIA) system with detection by atomic-absorption spectrometry (AAS). It is based on the formation of the Cu(DDTP)(2) complex and its extraction into chloroform, and back-extraction of the copper with an ammonia buffer (pH 10). The method uses small amounts of samples, avoids handling errors and is fast and highly reproducible. It features a detection limit of 0.39 ppm DDTP (2.45 x 10(-6)M in the organic phase) and a relative standard deviation of 1.6%. The method has been applied to the determination of the organophosphorus pesticide malathion in an agricultural formulation.

Determination of sunset yellow and tartrazine by differential pulse polarography.

A study has been made of the polarographic (DC and DPP) behaviour of the food dyes Sunset Yellow and Tartrazine in acid and alkaline media and in the absence and presence of polyvinylpyrrolidone. Methods are proposed for the determination of both dyes by DPP over a concentration range of 0.1-10 ppm. The methods have been applied to their determination in soft drinks.

Simultaneous spectrophotometric determination of erbium and praseodymium with 1-(2-pyridylazo)-2-naphthol in the presence of octylphenol poly(ethyleneglycol) ether (TX-100).

The optimum conditions for formation of Er-PAN and Pr-PAN complexes in micelles of TX-100 are described, and methods proposed for spectrophotometric determination of the two elements. The molar absorptivities were 5.0 x 10(4)1.mole(-1).cm(-1) for Er and 4.6 x 10(4)1.mole-1.cm(-1) for Pr. A simple method is proposed for simultaneous determination of Er and Pr without previous separation, based on a micellar masking process.

Potentiometric determination of hydrogen peroxide with permanganate in presence of fluoride, with iron as a catalyst: Application to the titanium-fluoride-peroxide mixed complex.

A potentiometric permanganate titration has been developed for the determination of hydrogen peroxide in the presence of fluoride, as well as of the peroxide content in the titanium-fluoride-peroxide mixed complex. It is based on the stabilization of manganese(III) with an excess of fluoride in a moderately acidic medium (pH close to 3) and on the use of iron(III) as catalyst. Errors are less than 0.5%.

Constant-potential electrolysis: determination of diffusion coefficients of thallium by using a hanging mercury drop electrode.

The technique of constant-potential electrolysis at a stationary spherical electrode (hanging mercury drop) was investigated for the determination of the diffusion coefficient of Tl(I) in sodium citrate-sodium hydroxide medium and of Tl in mercury. Current-time curves, at controlled potential, were obtained, covering periods from 1 to 25 sec after the start of the electrolysis. The influence of applied potential, time of electrolysis, convection and shielding of the electrode was studied.

Analytical chemistry of unusual oxidation states: the polarography of vanadium(IV) in cyanide medium.

The polarographic reduction wave for vanadium(IV) in cyanide medium has been studied and the effect of cyanide concentration on the diffusion current and half-wave potential has been interpreted, using the theory of irreversible but diffusion-controlled reduction. Coulometric experiments suggest a two-electron transfer, and the shift of half-wave potential corresponds to the addition of one cyanide ion during the reduction step. The proportionality of wave-height to vanadium concentration in the used alkaline cyanide medium indicates a possible analytical unity. The half-wave potential is about -1.1 V.

Determination of hexacyanoferrate(II) with electrolytically generated octacyanomolybdate(V).

The determination of hexacyanoferrate(II) with electrolytically generated octacyanomolybdate(V) at a platinum anode over a wide pH range is described. From 1 to 20 muequiv are determined with a relative standard deviation of 0.3%.