Successful prevalidation of the slug mucosal irritation test to assess the eye irritation potency of chemicals.

A previous 'in house' validation study showed that the SMI assay can be used as an alternative to the in vivo Draize eye irritation test. The aim of this multi-centre study with four participating laboratories was to assess the transferability and inter-laboratory variability of the assay using 20 reference chemicals covering the whole irritancy range. The eye irritation potency of the chemicals was assessed by measuring the amount of mucus produced during a 60-min contact period with a 1% dilution, and a second 60-min treatment with a 3.5% dilution. After each contact period the protein release from the mucosal surface was measured. Linear discriminant equations were used to convert the results into the corresponding EU eye irritation categories (NI, R36 and R41). All the non-irritants were predicted correctly by the four laboratories resulting in a 100% specificity. For the R36 compounds a correct classification rate of 89% (VITO) and 100% (SPL, JNJ and UGent) was obtained. The R41 compounds were classified correctly in 78% of the cases for VITO, 89% for SPL and JNJ and 100% for UGent. We can conclude that the SMI assay is a relevant, easily transferable and reproducible alternative to predict the eye irritation potency of chemicals.

Assessment of the renal circulation during pregnancy with color Doppler ultrasonography.

OBJECTIVES: A non-invasive method of assessing the renal vasculature during pregnancy would be useful in the management of patients with renal dysfunction resulting from preeclampsia or chronic renal disease. The objectives of this study were to determine (1) whether color ultrasonography during pregnancy facilitates Doppler interrogation of renal and intrarenal arteries, allowing (2) the assessment of differences between waveforms from nonpregnant and pregnant women and (3) the analysis of waveform variability throughout the kidney and between the right and left kidneys. STUDY DESIGN: In a cross-sectional study renal and intrarenal artery flow waveforms were obtained from women in early (12 to 19 weeks; n = 8), mid (20 to 29 weeks; n = 11), and late (30 to 37 weeks; n = 14) pregnancy with eight age-matched, nonpregnant women acting as controls. Waveforms were analyzed for pulsatility index, resistive index, and systolic/diastolic ratio. RESULTS: Left or right renal and upper- and lower-pole interlobar artery waveforms were obtained from all women. The mean pulsatility index values for the nonpregnant women were not significantly different from those women in early, mid, or late pregnancy. In the nonpregnant women, the left renal artery pulsatility index (1.13 +/- 0.13) was greater than the left lower interlobular artery pulsatility index (0.91 +/- 0.08; p < 0.05). During pregnancy renal and interlobar artery pulsatility index values were greater than those for the corresponding interlobular arteries, but the differences were not significant. Mean renal and intrarenal artery pulsatility index values were greater on the right, but the difference was significant only for the lower interlobular artery in midpregnancy. CONCLUSIONS: Pregnancy does not significantly affect renal and intrarenal artery flow waveforms, nor are there significant differences between waveforms from the renal and interlobar arteries.

The kinetics of papillotoxic doses of 3H-N-phenylanthranilic acid in rats.

N-phenylanthranilic acid (N-PAA; 4 mmol/kg/day p.o.) causes a diffuse renal papillary necrosis and a polyuria in 7 days. A single dose of 3H-N-PAA was widely distributed with second-order elimination kinetics, t1/2 +/- 50 h for stomach, heart, kidney, and bladder and t1/2 greater than or equal to 90 h for liver, spleen, muscle and lung. The estimated plasma t1/2 = 10.2 h, and over 75% was excreted via urine in 36 h and 13% via faeces in 72 h. In chronically cannulated animals 29% of N-PAA-derived material was in bile and 24% in urine at 36 h, which suggests enterohepatic circulation. Bile and urine contained several metabolites but no parent compound. Multiple doses for 8 and 16 days increased urinary N-PAA excretion to 90% in 36 h, but faecal contents decreased to 6-8% in 72 h and plasma t1/2 to less than or equal to 7.5 h.

Tumour uptake of thallium-201 chloride.

The uptake of 201Tl-chloride in tumours has recently been investigated in several authors' laboratories. We are reporting studies on the uptake in malignant melanoma in mice. Generally, we confirm the published data qualitatively in finding higher uptake in tumour than in muscles. We confirm the rapid blood clearance and high kidney concentration, but we did not measure the myocardial uptake. We observed the concentrations in kidney muscle and tumour to rise during the first four hours while that in the liver fell from one hour onwards. We did not observe markedly higher uptake in melanin rich tumour than in other tumours.

Performance characteristics of a gamma camera over a wide range of energies.

The problem of choosing which collimator to use for imaging a new isotope has been approached by collecting resolution and sensitivity data for a selected group of isotopes. These have been chosen to be readily available and to have generally a single gamma-ray only. Resolution and sensitivity plots for a low energy collimator and a high energy collimator are presented and their use with several isotopes of interest is discussed. The interpretation of recommedations in the literature on the choice of collimators for newly introduced isotopes would be considerably simpler if data in this format were commonly available.