Although the DN patients have inappropriately low EPO levels for the severity of their anaemia, they can mount an appropriate EPO response to moderate hypoxia. The mechanism underlying the EPO-deficient anaemia present in some diabetic patients remains unclear.

Background-We have consistently argued that mild asthma is an important underlying aetiological factor in patients with severe symptomatic hyperventilation. While hyperventilation has been demonstrated in acute asthma, there have been few studies in mild chronic asthma, and mechanisms are uncertain. Methods-Twenty Conclusion-Mild asymptomatic asthmais not associated with clinically significant hyperventilation but is associated with a significant reduction in both arterial and end tidal PCO 2 which relates to airway hyperresponsiveness rather than to the degree of airway obstruction or mucosal inflammation. Anxiety and depression appear not to be implicated.

Fifty-six Holstein calves were used to investigate effects of heat and cold stressors on mitogen-induced blastogenesis of isolated peripheral blood mononuclear cells and immunoglobulins G1 and M in blood plasma. Calves were exposed to constant hot (35 degrees C), constant cold (-5 degrees C), or thermoneutral (23 degrees C) ambient conditions in environmentally-controlled chambers. Immune responses were measured soon after introduction into environmental chambers (3 days) and after various degrees of adaptation (7 and 14 days). Mortality was greater among heat- and cold-exposed calves than among thermoneutral calves. Neither heat nor cold exposure had a direct effect on blastogenesis of peripheral blood mononuclear cells by phytohemagglutinin or concanavalin A. Plasma from heat- and cold-exposed calves then was incorporated into the culture medium at a final concentration of 5% and tested in a mitogenesis assay on peripheral blood mononuclear cells from a single healthy donor. Plasma from heat-exposed calves consistently enhanced tritiated thymidine incorporation into normal peripheral blood mononuclear cells by phytohemagglutinin and concanavalin A as compared to plasma from cold-exposed calves. After heat exposure for 3 to 14 days, immunoglobulin G1 averaged 27% less in heat-exposed calves than in calves that were held at thermoneutrality, but M was unaffected. Cold exposure did not have a consistent effect on G1 or M. These data demonstrate that chronic heat and cold stressors affect calves by altering both antibody- and cell-mediated immunity.

No abstract

2,4-Dichlorophenol (DCP) is a drinking and waste-water contaminant formed by the spontaneous reaction of chlorine with phenols following chlorination of water for disinfection and deodorization. Rats were exposed to 0, 3, 30, or 300 ppm DCP in drinking water either in utero or for 12 wk postnatally following in utero exposure. Toxicity to DCP was assessed by organ and body weight changes, histopathology, and effects on reproduction and immunocompetence. Reproductive parameters measured included conception, litter size, pup birth weight, number stillborn, survival to weaning, and weaning weight. Immune parameters assessed were humoral immunity (antibody production) by an indirect enzyme-linked immunosorbent assay (ELISA), cell-mediated immunity by a delayed-type hypersensitivity response, and macrophage function by phagocytosis of radiolabeled blood cells. Rats that received the combined in utero and postnatal treatment with 300 ppm DCP had significantly increased liver and spleen weights, enhanced humoral immune responsiveness, and depressed cell-mediated immunity. Histopathologic changes were unremarkable in DCP-exposed rats, even in the presence of increased liver and spleen weights. The 6-wk-old progeny of DCP-treated dams had normal immune functions and showed no signs of DCP toxicity, other than increased spleen weights in the 300-ppm exposure group. The results indicate that (1) the immune system may be a sensitive target for chlorinated phenolic compounds, (2) DCP may exert different effects on separate major immune responses, and (3) unlike some other chlorinated phenols, DCP does not appear to alter reproductive performance in rats.