Behavioral state-specific changes in human hippocampal theta activity

Although there has been extensive examination of the behavioral and physiologic correlates of hippocampal theta activity in animals, the human literature consists of a single case study. We investigated the differential effects of four behavioral states on human hippocampal theta activity in 16 epilepsy surgery patients. Behavioral conditions included resting eyes closed (RC), resting eyes open (RO), eyes open with auditory word activation (AW), and eyes open with visuospatial activation (VS). Hippocampal theta activity decreased during both RO and VS compared to both RC and AW. There were reciprocal changes in delta activity. Comparisons of RO to VS and of RC to AW were nonsignificant. The results demonstrate state-specific changes in human hippocampal theta and are consistent with the animal literature that relates hippocampal theta to sensorimotor integration and forebrain volitional mechanisms.     

Broadening the reach of cardiac rehabilitation to rural and remote Australia.

BACKGROUND: Cardiac rehabilitation (CR) has an evidence base but traditional models may not readily apply to people living in rural and remote regions. AIM:: To outline published comprehensive and non-hospital based CR models used for people discharged from hospital after a cardiac event that have potential relevance to those living in rural and remote areas in Australia. METHODS: The PubMed database was searched using Medical subject headings (MeSH) terms and the key word 'cardiac rehabilitation' limited to clinical trials. Articles were retrieved if they included at least two components of CR and were not based in an outpatient setting. RESULTS: No CR models specifically developed for rural and remote areas were identified. However, 14 studies were found that outlined 11 non-conventional comprehensive CR models. All provided CR in a home-based setting. Health professionals provided support via telephone contact or home visits, and via resources such as the Heart Manual. Reported outcomes from these CR programs varied: ranging from an increase in knowledge of risk factors, to improvements in physical activity, decreased risk factor profile, improved psychological and social functioning and reductions in health service costs and mortality. CONCLUSION: Home-based, CR models have the most substantive evidence base and, therefore the greatest potential to be developed and made accessible to eligible people living in rural and remote areas.     

Dioxin treatment of rats results in increased in vitro induction of sister chromatid exchanges by alpha-naphthoflavone: an animal model for human exposure to halogenated aromatics

Recent reports have shown that alpha-naphthoflavone (alpha-NF) in vivo enhances the sister chromatid exchange (SCE) frequency in lymphocytes from human populations exposed to cigarette smoke or polychlorinated biphenyls and dibenzofurans. In this study, female Sprague-Dawley rats (9-11 weeks old) were administered a single oral dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and killed 6 days after treatment. Blood cultures were established with or without alpha-NF. The baseline and alpha-NF-induced SCE frequencies were assessed in lymphocytes after a 72-hr culture period. No effect on the SCE baseline frequency (cultures without alpha-NF) was detected in rats exposed to 0-30 micrograms TCDD/kg. However, the SCE frequencies from cultures incubated in the presence of alpha-NF were significantly higher in lymphocytes from rats treated with TCDD. Moreover, delta SCE values (SCE alpha-NF minus SCE baseline) were significantly higher in lymphocytes from rats treated with TCDD than in controls. A dose-dependent increase in delta SCE values was observed between 0 and 3 micrograms TCDD/kg, followed by a plateau at higher doses. This induction pattern closely resembled the induction of the liver microsomal aryl hydrocarbon hydroxylase activity by TCDD. In contrast to TCDD, phenobarbital treatment of rats (75 mg/kg/day) had no effect on alpha-NF-induced SCE frequencies in lymphocytes. Liver microsomes from TCDD-treated rats metabolized alpha-NF at a rate much faster than that of control microsomes. These studies indicate that TCDD-exposed rats provide a useful model to investigate the mechanism of enhanced in vitro induction of SCE frequency in lymphocytes from humans exposed to toxic halogenated aromatics or cigarette smoke.     

Effect on mortality of inhalation injury

A retrospective analysis of 1,018 consecutive admissions with cutaneous burn injury over 32 months was carried out. Mortality probabilities as related to age, per cent TBSA burn, and presence of inhalation injury are presented. Incidence of and mortality from inhalation injury both rose with increasing burn area. The incidence of inhalation injury also rose with advancing age; mortality was lowest in the 5- to 14-year old age group and highest in those more than 59 years of age.     

Rice varieties with similar amylose content differ in starch digestibility and glycemic response in humans

Three high-amylose rice varieties, IR42, IR36, and IR62, with similar chemical composition including amylose content (26.7-27.0%), were cooked under the same conditions and tested for in vitro digestibility as well as blood glucose and insulin responses in healthy human volunteers. The starch-digestion rate and the glycemic and insulin responses were the highest in IR42, followed by IR36 and, then IR62. The differences were not due to unabsorbed carbohydrate but were related to their physicochemical properties, such as gelatinization temperature, minimum cooking time, amylograph consistency, and volume expansion upon cooking. When the three varieties were cooked for their minimum cooking time, they had the same degree of gelatinization and their starch-digestion rates and glycemic responses were similar. We conclude that amylose content alone is not a good predictor of starch-digestion rate or glycemic response. Rice varieties with similar high-amylose contents can differ in physicochemical (gelatinization) properties and this, in turn, can influence starch digestibility and blood glucose response.