Serum urea concentration and the risk of hepatotoxicity after paracetamol overdose.

BACKGROUND: Glutathione depletion increases the incidence of toxicity after paracetamol overdose. Risk factors for toxicity, including chronic ethanol excess and malnutrition, are associated with low serum urea concentrations. Therefore, we hypothesized that low serum urea concentration might itself be predictive of hepatotoxicity in patients that present to hospital after paracetamol overdose. METHODS: The present study prospectively collected data from 1085 patients attending the Emergency Department after paracetamol overdose. Hepatotoxicity was predefined by prothrombin time ratio >1.3 or alanine transaminase > or = 1000 U/l. Serum urea concentrations were considered in a stepwise multiple regression analysis that included paracetamol dose, co-ingestion of ethanol and other drugs, serum concentration, N-acetylcysteine, interval to treatment, vomiting and serum creatinine. RESULTS: Median (IQR) serum urea concentrations were 3.3 mmol/l (2.7-4.2 mmol/l) in those without risk factors, compared with 3.0 mmol/l (2.4-3.9 mmol/l) in those with chronic excess ethanol intake (P < 0.001 by Mann Whitney test) and 2.5 mmol/l (1.9-2.8 mmol/l) in patients with other risk factors (P < 0.001). Multivariate analysis found that serum urea concentrations were not independently associated with hepatotoxicity. CONCLUSION: Low serum urea concentration is not an independent risk factor for hepatotoxicity after paracetamol overdose.

Does the patient history predict hepatotoxicity after acute paracetamol overdose?

BACKGROUND: Initial management of patients who were presented to hospital after acute paracetamol overdose depends on the suspected amount ingested and more than 12 g is potentially fatal. However, the validity of this approach has received comparatively little attention. METHODS: The present study is sought to establish whether the stated paracetamol dose might predict systemic exposure and risk of hepatotoxicity. A prospective observational study of consecutive patients presenting to the Emergency Department due to acute paracetamol overdose was performed. Serum paracetamol concentrations between 4 and 15 h post-ingestion were compared with the Rumack-Matthew '200-line' nomogram, and hepatotoxicity was defined by prothrombin time ratio >1.3 or alanine transaminase > or =1000 U/l. RESULTS: There were 987 patients, and the stated quantity of paracetamol ingested was 0-12 g in 475 (48.1%), >12 g in 349 (35.4%) and unknown in 163 (16.5%). Ingestion of >12 g was associated with paracetamol concentration above the '200-line' in 31.8% (95% CI 27.1-36.9%) vs. 3.2% (1.9-5.2%), P < 0.0001 by chi2 proportional test, and associated with hepatotoxicity in 6.9% (4.6-10.1%) vs. 1.3% (0.5-2.8%), P = 0.0001. CONCLUSION: Therefore, ingestion of >12 g predicted higher paracetamol exposure and increased risk of hepatotoxicity and supports the validity of patient history in this context.

Phenotypic and genetic characterization of enteropathogenic Escherichia coli (EPEC) and entero-aggregative E. coli (EAEC) from diarrhoeal and non-diarrhoeal children in Libya.

A total of 50 Escherichia coli strains isolated in a Libyan hospital (20 from children with diarrhoea and 30 from healthy children) were investigated for their pathotypes and virulence traits. Altogether nine eae-positive (enteropathogenic E. coli, EPEC) and nine aggR-positive (entero-aggregative E. coli, EAEC) strains were identified. Significantly (P=0.001) more EPEC strains were identified from diarrhoeal patients (n=8) than from healthy controls (n=1), while six EAEC strains were identified from diarrhoeal and three from healthy children. Typical (eae(+), EAF(+), bfp(+)) EPEC strains (n=6) belonged to classical EPEC serogroups O55, O114, O127 and showed localized adherence on Hela cells. EAEC strains revealed genetic heterogeneity but uniformly adhered to HeLa cultures in an entero-aggregative adherence pattern. Antibiotic resistance frequently, characterized the strains. Sixty-eight percentage of the strains were resistant against at least one antibiotic and 30% harbored a class 1 integron independently of their clinical background. This is the first report from North Africa demonstrating the significance of EPEC and EAEC.

Use of the nitrocellulose-enzyme immunosorbent assay for rapid, sensitive and quantitative detection of human enteroviruses.

A modified enzyme immunosorbent assay (EIA) employing nitrocellulose (NC) membrane as a high-capacity solid phase was successfully employed for the sensitive and rapid detection of human enteric viruses, poliovirus and Coxsackievirus B-5. The sensitivity of the NC-EIA ranged from 7 to 70 pg of viral antigen diluted in phosphate-buffered saline. When virus was added to crude supernatants of mollusc tissue homogenates prepared by the standard procedure for the recovery of viruses in molluscs, the sensitivity was reduced by approximately 10-fold. The sensitivity of the NC-EIA for the detection of viral antigens was 10- to 100-fold higher than conventional EIA using polystyrene microtiter plates as solid phase supports. This simple, rapid and sensitive assay using minimal amounts of antibodies should prove to be a useful and practical diagnostic tool to augment infectivity assays currently employed by various virus monitoring procedures. The method also may be applicable for the detection of difficult to grow and/or non-cultivatable enteric viruses which may be present in sewage-contaminated environments.

Analysis of truncated distributions: mating speed in Drosophila melanogaster.

The distribution of mating speeds in wild-type Drosophila melanogaster is shown to be log normal. The analysis of mating speeds by methods for truncated distributions is validated, and unbiased estimates of the mean mating speed, the variance of mating speed, and the proportion of flies capable of ever mating are produced. In pair matings, not all pairs are capable of copulating, given even a 7-day mating period.

Fine structure of the ocellus of the cabbage looper moth (Trichoplusia ni).

The dorsal ocelli of adult cabbage looper moths were studied by light microscopy, and scanning and transmission electron microscopy. Each ocellus has a cuticular lens located on the distal end of a cuticular cone which encapsulates the receptor cells. There are two distinct types of receptor cells in the ocellus. Seventy large receptor cells from plate-like rhabdoms with several adjacent cells to produce a rhabdom network in the ocellus. Proximally ninety small receptor cells which have a disorganized microvillar rhabdomere are located at the base of the rhabdoms formed by the large cells. Extensive areas of gap junctions which occur between the rhabdoms and the membranes of large and small cells suggest that the cells may be electrically coupled to one another. Axons from both large and small receptor cells leave the base of the ocellus and extend to the protocerebrum to synapse with second order neurons.

The genetic basis of receptivity of yellow mutant Drosophila melanogaster females.

Yellow mutant females of Drosophila melanogaster are more receptive to yellow males than are wild-type females. By chromosomal substitution, this enhanced receptivity has been localized to the X chromosome. Repeated backcrossing between a yellow and wild-type inbred line, with the yellow locus maintained segregating, allows the conclusion that the yellow locus itself is responsible for the enhanced female receptivity.