Altered protein expression in neutrophils of calves treated with dexamethasone

The effect of glucocorticoid treatment on protein expression in bovine neutrophils was examined with a proteomic approach to address the mechanisms by which stress alters neutrophil function and predisposes to bacterial pneumonia in cattle. Calves 6 to 8 mo old were treated with dexamethasone (0.1 mg/kg), neutrophils were isolated 24 h later, and whole-cell lysates were examined by 2-dimensional electrophoresis. Differentially expressed protein spots were identified by peptide mass fingerprinting. The antimicrobial protein lactotransferrin was detected at increased amounts in the neutrophils of the dexamethasone-treated calves. Proteins detected at reduced amounts in the neutrophils of the dexamethasone-treated calves included annexin 1, phosphoglycerate mutase, Na(+) - K+ ATPase, and cathelicidin 1. These findings identify glucocorticoid-induced changes in the levels of neutrophil proteins involved in host defense, inflammation, and cellular metabolism and suggest additional mechanisms by which glucocorticoids affect neutrophil function.     

Carbon Dioxide Transport by Ocean Currents at 25{degrees}N Latitude in the Atlantic Ocean

Measured concentrations of CO(2), O(2), and related chemical species in a section across the Florida Straits and in the open Atlantic Ocean at approximately 25 degrees N, have been combined with estimates of oceanic mass transport to estimate both the gross transport of CO(2) by the ocean at this latitude and the net CO(2) flux from exchange with the atmosphere. The northward flux was 63.9 x 10(6) moles per second(mol/s); the southward flux was 64.6 x 10(6) mol/s. These values yield a net CO(2) flux of 0.7 x 10(6) mol/s (0.26 +/- 0.03 gigaton of C per year) southward. The North Atlantic Ocean has been considered to be a strong sink for atmospheric CO(2), yet these results show that the net flux in 1988 across 25 degrees N was small. For O(2) the equivalent signal is 4.89 x 10(6) mol/s northward and 6.97 x 10(6) mol/s southward, and the net transport is 2.08 x 10(6) mol/s or three times the net CO(2) flux. These data suggest that the North Atlantic Ocean is today a relatively small sink for atmospheric CO(2), in spite of its large heat loss, but a larger sink for O(2) because of the additive effects of chemical and thermal pumping on the CO(2) cycle but their near equal and opposite effects on the CO(2) cycle.     

Effects of chlorination of chill water on the bacteriologic profile of raw chicken carcasses and giblets.

In March 1989, the USDA Food Safety and Inspection Service sampled raw chicken carcasses and giblets at a federally inspected slaughter establishment in Puerto Rico to determine the effects of adding chlorine to carcass and giblet chill water on bacterial contents of raw poultry products. Over four 8-hour workdays, 200 carcass rinse samples were collected at 3 sites in the establishment; 39 giblet rinse samples were collected at 1 site. Analyses of the carcass rinse samples indicated that carcasses had average aerobe plate counts of log10 3.20 before chilling and 2.51 after chilling; Enterobacteriaceae counts of log10 2.57 before chilling and 1.75 after chilling; and Escherichia coli counts of log10 2.04 before chilling and 1.20 after chilling. Salmonellae were found on 43% of the carcasses before chilling and on 46% after chilling. Analyses of the giblet and neck rinse samples indicated that raw giblets and necks after chilling had average aerobe plate count of log10 3.49, Enterobacteriaceae count of log10 2.57, and E coli count of log10 1.06. Salmonellae were found on 12% of the giblets and necks sampled. Results compared favorably with giblet and neck rinse sample results obtained during a baseline sampling study in November and December 1987. The baseline results indicated aerobe plate count of log10 3.72; Enterobacteriaceae count of log10 2.90; E coli count of log10 1.14; and salmonellae on 69% of the giblets and necks sampled. Placing raw chicken carcasses in chlorinated chill water reduced aerobe, Enterobacteriaceae, and E coli plate counts. Prevalence of carcasses with salmonellae remained nearly the same.(ABSTRACT TRUNCATED AT 250 WORDS)     

Diversity of Salmonella serotypes in cull (market) dairy cows at slaughter.

OBJECTIVE: To determine the diversity of Salmonella serotypes isolated from a large population of cull (market) dairy cows at slaughter. DESIGN: Cross-sectional study. SAMPLE POPULATION: Salmonella organisms isolated from the cecal-colon contents of 5,087 market dairy cows. PROCEDURE: During winter and summer 1996, cecal-colon contents of cull dairy cows at slaughter were obtained from 5 US slaughter establishments. Specimens were subjected to microbiologic culturing for Salmonella spp at 1 laboratory. Identified isolates were compared with Salmonella isolation lists published by the Centers for Disease Control and Prevention (CDC) and the National Veterinary Services Laboratory (NVSL) for approximately the same period. The Simpson diversity index was used to calculate the likelihood that Salmonella isolates selected randomly by establishment were different. RESULTS: Of 58 Salmonella serotypes identified, Salmonella ser. Montevideo was the most prevalent. Two of the top 10 CDC serotypes identified from in 1996, Salmonella ser. Typhimurium and S Montevideo, appeared on our top 10 list; 8 of the top 10 were found on NVSL listings. Thirty-one of 59 S. Typhimurium isolates were identified as DT104 and found at a west slaughter establishment, 30 during the winter and 1 during the summer. The greatest diversity of serotypes was at a southeast establishment during the summer; the least diversity was at a central establishment in the winter. CONCLUSIONS AND CLINICAL RELEVANCE: 58 Salmonella serotypes were isolated from market dairy cows at slaughter and could pose a threat for food-borne illness. Salmonella Montevideo was the most frequently isolated serotype and may contribute substantially to salmonellosis in dairy cattle.     

Clinical, echocardiographic, and neurohormonal effects of a sodium-restricted diet in dogs with heart failure

The use of low-sodium diets in dogs with heart failure is common practice, but randomized, double-blind studies have not been conducted to examine the benefits or problems with this approach. The purpose of this study was to determine the effects of a low-sodium diet on clinical, echocardiographic, and neurohormonal parameters in dogs with heart failure. Dogs with stable chronic heart failure were fed exclusively a low-sodium (LS) and a moderate-sodium (MS) diet for 4 weeks each in a randomized, double-blind, crossover design. At days 0, 28, and 56, echocardiography and thoracic radiography were performed, and blood was analyzed for electrolytes and neurohormones. Fourteen dogs completed the study (9 with chronic valvular disease and 5 with dilated cardiomyopathy). Electrolyte abnormalities were common during the study, and serum sodium and chloride concentrations decreased significantly on the LS diet. Neurohormones did not change significantly between diet groups. Maximum left atrial (P = .05) and standard left atrial (P = .09) size decreased on the LS diet. For dogs with chronic valvular disease, vertebral heart score (P = .05), left ventricular internal dimension in diastole (P = .006) and systole (P = .02), standard left atrial dimension (P = .03), maximum left atrial dimension (P = .02), end-diastolic volume index (P = .02), and end-systolic volume index (P = .04) decreased significantly on the LS diet compared to the MS diet. Although analysis of these data suggests some benefits of a low-sodium diet, future studies with improved study design are needed to further evaluate the advantages and disadvantages of sodium restriction in dogs with heart failure.     

Scopolamine in racing horses: Trace identifications associated with dietary or environmental exposure

Scopolamine (l-hyoscine) identifications, often in small-number clusters, have been reported worldwide in performance horses over the last 30 years. Scopolamine is an Association of Racing Commissioners International (ARCI) class 3, penalty class B, substance with potential to affect performance. As such, scopolamine identification(s) in race or performance horses can result in significant penalties for the connections of the horse(s). Reviewed here is the worldwide distribution of scopolamine containing plants (primarily Datura spp.), with estimates of their potential toxicity to horses through dietary and/or environmental exposure. Also reviewed are the basic pharmacology of scopolamine and its precursor, urinary concentrations following feedstuff exposure, and the probable pharmacological/forensic significance of such findings.Based on an overview of the world literature on scopolamine, the expected characteristics of inadvertent environmental exposure are also presented with a view to making clear the potential of scopolamine identifications, with or without atropine, as a direct and expected outcome of both the worldwide distribution of scopolamine-containing plants and the sensitivity of modern equine drug testing. It is of particular interest that only 2/30 reported post-event equine identifications of scopolamine have been associated with atropine, suggesting that failure to identify atropine is not a biomarker of pharmaceutical administration of scopolamine. Available quantitative information associated with scopolamine identifications is consistent with the 75 ng/mL regulatory threshold for scopolamine currently used in Louisiana racing in the USA and the 30 ng/mL reporting threshold in effect in European racing.     

Syneresis of vitreous by carbon dioxide laser radiation

In carbon dioxide laser surgery of the vitreous a process of vaporization has been advocated. In this report syneresis, a thermal liquefaction of gel, is shown to be over ten times more efficient on an energy basis than vaporization. Syneresis of vitreous is experimentally shown to be a first-order kinetic process with an activation energy of 41 +/- 0.5 kilocalories per mole. A theory of laser surgery in which this figure is used agrees closely with results from laser experiments on human eye-bank vitreous. The syneresis of vitreous by carbon dioxide laser radiation could lead to a more delicate form of ocular microsurgery, and application to other biological systems may be possible.     

Control of mRNA decay by heat shock-ubiquitin-proteasome pathway

Cytokine and proto-oncogene messenger RNAs (mRNAs) are rapidly degraded through AU-rich elements in the 3' untranslated region. Rapid decay involves AU-rich binding protein AUF1, which complexes with heat shock proteins hsc70-hsp70, translation initiation factor eIF4G, and poly(A) binding protein. AU-rich mRNA decay is associated with displacement of eIF4G from AUF1, ubiquitination of AUF1, and degradation of AUF1 by proteasomes. Induction of hsp70 by heat shock, down-regulation of the ubiquitin-proteasome network, or inactivation of ubiquitinating enzyme E1 all result in hsp70 sequestration of AUF1 in the perinucleus-nucleus, and all three processes block decay of AU-rich mRNAs and AUF1 protein. These results link the rapid degradation of cytokine mRNAs to the ubiquitin-proteasome pathway.