Use of E mu-PIM-1 transgenic mice short-term in vivo carcinogenicity testing: lymphoma induction by benzo[a]pyrene, but not by TPA

E mu-pim-1 transgenic mice are predisposed to develop lymphomas. Due to their low spontaneous tumour incidence and their increased sensitivity towards the lymphomagen ethylnitrosourea these mice may present an interesting model for short-term carcinogenicity testing. Here, we report on the further exploration of this transgenic mouse model with two additional carcinogens known to have, among others, the lymphohaematopoietic system as target, i.e. benzo[a]pyrene (B[a]P) and 12-O-tetradecanoylphorbol-13-acetate (TPA). B[a]P, given three times a week (by gavage) for 13 weeks at 4.3, 13 or 39 mg/kg body weight, resulted in a dose-related increase in lymphomas up to a 90% incidence in E(mu)-pim-1 mice during the observation period of 40 weeks. B[a]P also induced tumours of the forestomach within this observation period, though at a lower incidence and apparently equally effective in wildtype and transgenic mice. TPA, on the other hand, was unable to induce lymphomas (or tumours in any other organ) in either transgenic or wildtype animals within the observation period of 44 weeks, when applied dermally at the maximum tolerated dose of 3 microg/mouse, twice a week for 35 weeks. Molecular analysis showed that B[a]P-induced lymphomas in transgenic mice were of T-cell origin, 80% of which had elevated levels of c-myc expression. None of the lymphomas had increased N-myc expression and mutation analysis of the ras-gene family revealed a K-ras mutation in only one out of eight tumours investigated. Also, none of the lymphomas showed aberrant expression of p53 as determined by immunohistochemistry. It is concluded that the E mu-pim-1 mouse model will not be very suitable for short-term carcinogenicity testing in general: only genotoxic chemicals that have the lymphohaematopoietic system as target for carcinogenesis in wild- type mice, appear to be efficiently identified.      

Housing and health: The relationship between research and policy

There is a long tradition of using housing interventions to promote public health, despite causative factors being unclear. This article reviews the research evidence on the key aspects of poor housing such as inadequate maintenance, over crowding, low temperatures and dampness, that have been identified as contributing to the impact of housing on health. Possible intervening factors such as house dust mites and fungi are also reviewed. This evidence is discussed in the context of possible confounding factors such as housing location and tenure. Conclusions are drawn about the adequacy of the research evidence as a basis for changing building regulations and other policy measures as a way of improving health.     

Five American authors on wealth, poverty, and inequality

There is much to be gleaned from novels concerning the links between wealth and power, inequality and corruption, poverty and illness. A student of social epidemiology will profit as much from close reading of these classics as from consulting textbooks on social stratification.     

Oral pharmacokinetics of omeprazole and lansoprazole after single and repeated doses as intact capsules or as suspensions in sodium bicarbonate

BACKGROUND: Omeprazole and lansoprazole can be given in sodium bicarbonate as, respectively, simplified omeprazole suspension and simplified lansoprazole suspension. We previously found the antisecretory effect of omeprazole 20 mg given as simplified omeprazole suspension to be lower than with intact capsules. However, lansoprazole 30 mg as simplified lansoprazole suspension produced an effect similar to that seen with intact capsules. AIM: To evaluate the absorption of both drugs when given orally as capsules or as suspensions in sodium bicarbonate. METHODS: In random order, we gave 5-day courses of omeprazole 20 mg and lansoprazole 30 mg as capsules and as suspensions in sodium bicarbonate to 12 healthy women. Serial blood samples were taken on days 1 and 5 of each course for pharmacokinetic measurements. RESULTS: There was impairment of omeprazole absorption when given as simplified omeprazole suspension. Maximum plasma concentration and area under the concentration/time curve were lower with simplified omeprazole suspension than with omeprazole capsules (P=0.034 and 0.013, respectively, on day 5). No differences were found in lansoprazole absorption when simplified lansoprazole suspension was compared with its standard capsule formulation. Relative bioavailability of omeprazole from simplified omeprazole suspension compared to the capsule was 58.4% on day 5. The corresponding value for lansoprazole was 84.7%. CONCLUSIONS: Simplified omeprazole suspension 20 mg does not supply adequate omeprazole for systemic absorption. Lansoprazole absorption from simplified lansoprazole suspension is maintained.     

Vancomycin minimum inhibitory concentration,host comorbidities and mortality in Staphylococcus aureus bacteraemia

We reported an association between elevated vancomycin MIC and 30-day mortality in patients with Staphylococcus aureus bacteraemia (SAB), including patients with methicillin-susceptible S. aureus (MSSA) treated with flucloxacillin. A detailed analysis of comorbidities and disease severity scores in the same cohort of patients was performed to ascertain if unknown clinical parameters may have influenced these results. The association between elevated vancomycin MIC and 30-day mortality in SAB remained significant (p 0.001) on multivariable logistic regression analysis even when accounting for clinical factors. In addition, the association persisted when restricting analysis to patients with MSSA bacteraemia treated with flucloxacillin. This suggests that elevated vancomycin MIC is associated with but not causally linked to an organism factor that is responsible for increased mortality.     

Chemistry of maculotoxin: a potent neurotoxin isolated from Hapalochlaena maculosa

The toxin from Hapalochlaena maculosa (the blue-ringed octopus) has been isolated in a chromatographically pure state. The toxin (maculotoxin) is a stable, highly polar compound, having a relatively low molecular weight. Maculotoxin behaves as a cation under certain conditions and was shown to be chemically similar to, but distinct from, tetrodotoxin.