The unwelcome houseguest: secondary household transmission of norovirus.

Norovirus is the leading cause of acute gastroenteritis in the USA. Although secondary household transmission of norovirus is frequently reported in outbreaks, little is known about specific risk factors for susceptibility and infectiousness in the household. Three norovirus outbreaks were investigated and data were collected on individuals exposed in the primary outbreak setting and their household members. Potential individual- and household-level risk factors for susceptibility and infectiousness were assessed using univariate and multivariate generalised linear mixed models. In the univariate models, the secondary attack rate (SAR) was significantly higher when living in a household with two or more primary cases (incidence rate ratio (IRR) = 2·1; 95% confidence interval (CI) 1·37-3·29), more than one primary case with vomiting (IRR = 1·9; CI 1·11-3·37), and at least one primary case with diarrhoea (IRR = 3·0; CI 1·46-6·01). After controlling for other risk factors in the multivariate models, the SAR was significantly higher among those living in a household with two or more primary cases (adjusted IRR = 2·0; CI 1·17-3·47) and at least one primary case with diarrhoea (adjusted IRR = 2·8; CI 1·35-5·93). These findings underscore the importance of maintaining proper hygiene and isolating ill household members to prevent norovirus transmission in the household.

Microneurovascular allotransplantation of the canine tongue.

INTRODUCTION: Reconstruction of the tongue with existing methods of tissue transfer often leaves glossectomy patients with significant deficits in speech and swallowing. The critical role of the tongue is implied by its unique structure and function. This paper reports the development of an animal model of hemitongue allotransplantation and documents functional and anatomic outcomes of this procedure. METHODS: Ten pairs of unmatched dogs underwent reciprocal exchange of the left hemitongue with microneurovascular replantation. The unoperated hemitongue acted as the control. Under cyclosporine immunosuppression, animals surviving long term underwent clinical observation, before electromyography, force transduction studies, and histological evaluation being euthanized. RESULTS: Five animals survived between 6 and 13 months for long-term evaluation. The remaining group were euthanized because of or died of overwhelming infection or uncontrollable transplant rejection. The latter sometimes resulted from difficulty in the delivery of the cyclosporine. Clinical recovery of tongue function was observed, as well as resumption of motor unit potential activity on electromyography. Contractile force recovery of the transplanted tongue averaged 68% of control (range, 47%-97%), and histological study of the hypoglossal and lingual nerves demonstrated anatomic evidence of reinnervation. Preservation of muscle, mucosal, and stromal ultrastructure was seen with light microscopy of the transplanted tongue. CONCLUSIONS: Allotransplantation of the hemitongue and associated neurovascular apparatus is possible in a large mammalian model, with long-term survival of tissue being accompanied by partial recovery of contractile properties. Anatomical and clinical evidence also points to sensory recovery. These data support the future possibility of employing a similar technique in glossectomy patients.

Maturation of antioxidant enzymes in rat small intestine: lack of glucocorticoid stimulation.

We report in detail the ontogeny and the response of antioxidant enzymes to glucocorticoids in the rat small intestine. Pregnant rats in the treatment group received four injections of dexamethasone starting on days 18, 19, or 20 of gestation; fetuses were killed 2 days later. Control rats were injected with 0.9% saline solution. Postnatal rats reaching 14, 19, and 104 days of age received four injections of hydrocortisone and were killed 2 days later. Age-matched controls were injected with 0.9% saline solution. The activities of xanthine oxidase, superoxide dismutase, and catalase were measured in small intestines from fetal (20 and 21 days gestation), newborn, and older (aged 16, 21, and 106 days) rats. Xanthine oxidase rose with maturation; the major increase occurred on postnatal day 21. Catalase and superoxide dismutase rose minimally during intrauterine life. On day 16 postpartum, catalase and superoxide dismutase values were 160% and 60%, respectively, higher than at birth. Glucocorticoid administration stimulated maltase and sucrase activities, but had no effect on the antioxidant enzymes or xanthine oxidase.