Acute exposure to gas‐supersaturated water does not affect reproductive success of female adult chinook salmon late in maturation

At times, total dissolved gas concentrations in the Columbia and Snake rivers have been elevated due to involuntary spill from high spring runoff and voluntary spill used as a method to pass juvenile salmonids over dams. The goal of this project was to determine if acute exposure to total dissolved gas supersaturation (TDGS) affects the reproductive performance of female chinook salmon late in their maturation. During this study, adult female spring chinook salmon were exposed to mean TDGS levels of 114.1% to 125.5%. We ended exposures at first mortality, or at the appearance of impending death. Based on this criterion, exposures lasted from 10 to 68 h and were inversely related to TDGS. There was no effect of TDGS on pre‐spawning mortality or fecundity when comparing treatment fish to experimental controls or the general hatchery population four to six weeks after exposures. Egg quality, based on egg weight and egg diameter, did not differ between treatment and control fish. Fertilization rate and survival to eyed‐stage was high ( > 94%) for all groups. With the exception of Renibacterium salmoninarum (the causative agent of bacterial kidney disease; BKD), no viral or bacterial fish pathogens were isolated from experimental fish. The prevalence (about 45%) and severity of R. salmoninarum did not differ among the groups or the general hatchery population. We conclude that these acute exposures to moderate levels of gas‐supersaturated water—perhaps similar to that experienced by immigrating adult salmon as they approach and pass a hydropower dam on the Columbia River—did not affect reproductive success of female chinook salmon late in their maturation. These results are most applicable to summer and fall chinook salmon, which migrate in the summer/fall and spawn shortly after reaching their natal streams. Published in 2004 by John Wiley & Sons, Ltd.     

Inhibition of heterocyclic aromatic amine formation in fried ground beef patties by garlic and selected garlic-related sulfur compounds

The effects of garlic and selected organosulfur compounds (diallyl disulfide, dipropyl disulfide, diallyl sulfide, allyl methyl sulfide, allyl mercaptan, cysteine, and cystine) on the formation of heterocyclic aromatic amines (HAAs) in fried ground beef patties were evaluated. Minced garlic cloves (ca. 4.8 to 16.7%, wt/wt) or organosulfur compounds (0.67 mmol) were added directly to ground beef. Patties (100 g) were fried at 225 degrees C (surface temperature) for 10 min per side. Two patties were fried for each replication, and five replicates were analyzed for each treatment. For each replicate, four subsamples were analyzed (two unspiked subsamples for concentration and two spiked subsamples for the recovery of HAA standards). The volatile sulfur compounds significantly (P < 0.05) reduced concentrations of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine by reductions of 46 to 81%, while average reductions of 35, 22, and 71%, were achieved with cystine, cysteine, and whole garlic, respectively. The volatile sulfur compounds reduced concentrations of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline by 34 to 67%, while reductions of 25, 19, and 63% (P < 0.05) were achieved with cystine, cysteine, and whole garlic, respectively. These studies confirm that garlic and some organosulfur compounds have the potential to reduce HAA formation incooked beef patties.     

Time to clinical stability in patients hospitalized with community-acquired pneumonia: implications for practice guidelines

CONTEXT: Many groups have developed guidelines to shorten hospital length of stay in pneumonia in order to decrease costs, but the length of time until a patient hospitalized with pneumonia becomes clinically stable has not been established. OBJECTIVE: To describe the time to resolution of abnormalities in vital signs, ability to eat, and mental status in patients with community-acquired pneumonia and assess clinical outcomes after achieving stability. DESIGN: Prospective, multicenter, observational cohort study. SETTING: Three university and 1 community teaching hospital in Boston, Mass, Pittsburgh, Pa, and Halifax, Nova Scotia. PATIENTS: Six hundred eighty-six adults hospitalized with community-acquired pneumonia. MAIN OUTCOME MEASURES: Time to resolution of vital signs, ability to eat, mental status, hospital length of stay, and admission to an intensive care, coronary care, or telemetry unit. RESULTS: The median time to stability was 2 days for heart rate (< or =100 beats/min) and systolic blood pressure (> or =90 mm Hg), and 3 days for respiratory rate (< or =24 breaths/min), oxygen saturation (> or =90%), and temperature (< or =37.2 degrees C [99 degrees F]). The median time to overall clinical stability was 3 days for the most lenient definition of stability and 7 days for the most conservative definition. Patients with more severe cases of pneumonia at presentation took longer to reach stability. Once stability was achieved, clinical deterioration requiring intensive care, coronary care, or telemetry monitoring occurred in 1% of cases or fewer. Between 65% to 86% of patients stayed in the hospital more than 1 day after reaching stability, and fewer than 29% to 46% were converted to oral antibiotics within 1 day of stability, depending on the definition of stability. CONCLUSIONS: Our estimates of time to stability in pneumonia and explicit criteria for defining stability can provide an evidence-based estimate of optimal length of stay, and outline a clinically sensible approach to improving the efficiency of inpatient management.     

The role of mineralocorticoid receptors in hypothalamic-pituitary-adrenal axis regulation in humans

In rodents, two types of glucocorticoid receptors, the mineralocorticoid (MR; type I) and the glucocorticoid (type II) receptors, have been demonstrated to play a role in hypothalamic-pituitary-adrenal (HPA) axis regulation. Because MR shows a very high affinity for cortisol, it has been suggested that MR plays an important role in restraint of CRH and ACTH secretion during the nadir of the circadian rhythm. Although a number of studies have established the importance of MR in rodents, the functional role of MR in humans has not been determined. These studies evaluated whether spironolactone, an MR antagonist, had a detectable effect on HPA axis regulation in humans, and whether the effect was greatest during the evening, when plasma cortisol concentrations are in the MR range. Compared to the placebo day, after a single dose of spironolactone at either 0800 or 1600 h, there is a significant increase in plasma cortisol, which is preceded by a rise in ACTH and beta-endorphin. A significant effect of spironolactone on cortisol secretion was demonstrated with no differences between the morning and evening. Because the effect of spironolactone on cortisol was short lived, a second experiment was conducted using two doses of spironolactone, again sampling in the morning and evening. After two doses of spironolactone, plasma cortisol levels showed a significant and sustained spironolactone-induced elevation for the entire sampling period. However, neither plasma beta-endorphin nor ACTH was increased compared to levels on the placebo day. These data suggest that MR appear to play a clear role in HPA axis regulation during the time of the circadian peak as well as the trough. Furthermore, MR blockade may affect the sensitivity of the adrenal to ACTH.