Hypothermia protects brain function in acute carbon monoxide poisoning

The role of body temperature in the morbidity and mortality resulting from acute severe carbon monoxide (CO) poisoning (2400 ppm CO, 90 min) was investigated using an unanesthetized animal model. Modified Levine prepared female rats (left common carotid artery and jugular cannulated) displayed a lower rate of recovery period (4 hr) re-warming, and an increased mortality rate and behaviorally-assessed neurologic index (NI) compared to normal rats. This indicated their greater susceptibility to CO hypoxia, although the degree of CO-induced hypothermia was the same in both groups. The whole-body cooling of Levine rats to a similar extent prior to CO exposure increased somewhat the post-CO re-warming rate, and marginally decreased NI and mortality during CO exposure (in-CO). In contrast, maintenance of constant body temperature by external heating during CO exposure resulted in a negative post-CO re-warming rate and sharply increased NI and in-CO mortality. Normal euthermic rats were much less severely affected by CO. The results suggest that hypothermia, whether CO-induced or produced by prior cooling, provides measurable protection of brain function during acute severe CO poisoning, and that maintenance of body temperature increases in-CO mortality and interferes with ability to thermoregulate and increases NI in survivors.     

Water, trachoma and conjunctivitis.

The incidence of eye infections in a community is generally accepted as an indicator of the adequacy of water supply for their needs. However, discrepancies in the published results from various studies seem to challenge this view. We have reanalysed the published data on trachoma in relation to the most relevant indicators of water accessibility, using prevalence ratios as the single parameter for risk assessment. A definite trend emerges from this review: the incidence of infectious conjunctivitis is not sensitive to differences in water accessibility; on the other hand, a reduction in the risk of trachoma is consistently associated with better access to water. This conclusion may support the efforts of WHO and other multilateral and bilateral agencies to sustain the commitment towards the water supply sector beyond the International Drinking Water Supply and Sanitation Decade.     

Functional characteristics of intraepithelial lymphocytes from mouse small intestine. III. Inability of intraepithelial lymphocytes to induce a systemic graft-versus-host reaction is because of failure to migrate in vivo.

In this study we have investigated whether addition of bone marrow accessory cells or concurrent administration of recombinant IL-2 would allow intraepithelial lymphocytes (IEL) to induce a systemic, lethal GvHR in irradiated hosts. In addition we have studied the ability of IEL to migrate into lymphoid tissues after intravenous injection and compared this with their locomotor capacity in vitro.     

Free radicals and cardioplegia: the absence of an additive effect with allopurinol pretreatment and the use of antioxidant enzymes in the rat

The isolated perfused working rat heart model of cardiopulmonary bypass was used to assess whether (a) allopurinol pretreatment enhances resistance to normothermic (30 min) or hypothermic (4 h) ischemia; (b) addition of antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) to cardioplegic and/or reperfusion solutions are protective; (c) any protective effects are additive. With normothermic ischemia, allopurinol pretreatment improved recovery of aortic flow from its control value of 25 +/- 3% to 48 +/- 6% (P less than 0.05). Similarly, SOD plus CAT used during both ischemia and reperfusion improved recovery of aortic flow from a control value of 28 +/- 4% to 48 +/- 6% (P less than 0.05). However, various combinations of the two types of intervention afforded no additive protection. Under hypothermic (21 degrees C) conditions, allopurinol pretreatment was not effective, whereas SOD and CAT added during ischemia and reperfusion improved recovery of aortic flow from its control value of 53 +/- 4% to 69 +/- 5% (P less than 0.05). This value was similar to allopurinol pretreatment and SOD plus CAT added during ischemia and reperfusion (69 +/- 6%: P less than 0.05). These results provide further evidence that reperfusion-induced free radical formation may adversely affect postischemic recovery of function. The absence of an additive effect suggests a common mechanism of action, which is likely to involve the free radical-generating enzyme xanthine oxidase; however, other mechanisms may exist. Our results further support the use of antifree radical intervention in conjunction with cardioplegia to protect the heart during ischemia and reperfusion.