The failure of selenium supplementation to prevent copper-induced liver damage in Fischer 344 rats.

This study evaluates the ability of selenium (Se) supplementation to prevent experimental copper (Cu)-induced hepatocellular damage. Weanling male Fischer 344 rats were randomly assigned to groups of 15, 3 groups (A,B,C) were fed Cu-loaded diets (containing 2000 microg/g copper, added as CuSO4) and different levels of Se (added as Na2SeO3 x 5H2O) as follows: A) Cu-loaded/Se adequate diet (0.4 microg/g Se, fed basis); B) Cu-loaded/Se-supplemented diet (2 microg/g Se); and C) Cu-loaded/Se-deficient diet (< 0.2 microg/g). Three additional groups (D,E,F) were fed diets containing adequate levels of Cu (14 microg/g Cu, fed basis) and different levels of Se as follows: D) Cu-adequate/Se-adequate diet; E) Cu-adequate/Se-supplemented diet (2 microg/g Se); and F) Cu-adequate/Se-deficient (< 0.2 microg/g) diet. After 4, 8, and 12 weeks on the experimental diets, liver samples were processed for histology, histochemistry, metal analysis, glutathione peroxidase (GSH-Px) measurement, and quantification of malondialdehyde (MDA). Morphologic changes characteristic of Cu-associated hepatitis, without an increase in hepatic MDA levels, were seen in all Cu-loaded rats in each sampling. Similar changes occurred in rats fed Se-adequate, Se-supplemented and Se-deficient diets. This study demonstrates that Fischer 344 rats fed 2000 microg/g Cu develop morphologic changes due to Cu toxicity without evidence of lipid peroxidation. Furthermore, Se supplementation does not result in protection against Cu-induced liver injury.     

Cardiogenic shock and cardiac arrest.

Severe heart disease may cause hypotension and hypoperfusion, and ultimately circulation may cease altogether. These two clinical syndromes are cardiogenic shock and cardiac arrest, respectively. This review summarizes the causes and clinical features of each, and describes the treatment options available to clinicians managing patients in cardiogenic shock.     

Bovine spongiform encephalopathy in Northern Ireland: epidemiological observations 1988-1990.

This study describes the epidemiological features of bovine spongiform encephalopathy (BSE) in Northern Ireland where the first case occurred in November 1988. They were very similar to those observed in Great Britain except that the annual incidence of BSE in 1990 in Northern Ireland, 2.3 confirmed cases per 10,000 adult cows, was approximately one 10th of that in Great Britain. The findings were also consistent with the current hypothesis that affected cattle had been exposed to a scrapie-like agent via cattle feedstuffs containing ruminant-derived protein. However, a preliminary investigation of the potential sources of infection for cattle in Northern Ireland did not provide any conclusive evidence.     

ULTRASONOGRAPHY OF ALIMENTARY LYMPHOSARCOMA IN THE CAT

Clinical, radiological and ultrasonographic findings from 22 cats with gastrointestinal lymphosarcoma were reviewed. The most common clinical findings were anorexia, weight loss, vomiting, lethargy, depression, fever, anemia and a palpable abdominal mass. Abdominal radiographs of 12 cats revealed a mass associated with the gastrointestinal tract and/or mesentery, and decreased serosal detail, suggestive of peritoneal effusion. The most common ultrasonographic finding was transmural gastric or intestinal thickening associated with loss of normal wall layering, reduced wall echogenicity and localized hypomotility. As is noted in people, other patterns such as transmural-segmental, transmural-nodular, transmural-bulky and mucosal infiltration were represented. In 3 cats, mesenteric lymph-adenopathy was responsible for most of the mass-effect. Fine-needle aspiration biopsy, automated microcore biopsy, endoscopic biopsy or necropsy confirmed the diagnosis of lymphosarcoma in all cats. Chemotherapy was instituted in 19 cats. Only 6 cats had a complete response to treatment. The results of this study indicate that ultrasonography is a valuable tool for the diagnosis of feline alimentary lymphosarcoma and that biopsies can be obtained under ultrasonographic guidance.     

Serum biochemistry of Zebu bulls and their Friesian crosses fed two planes of protein

Twenty-one Bunaji (White Fulani, Zebu) and 21 Friesian X Bunaji cross-bred bull calves, approximately 6 months of age, were each divided after weaning into two groups and fed isocaloric rations containing 14.45% (high protein) and 8.51% (low protein) crude protein for 10 months. Serum samples were collected biweekly for 10 months and analysed for serum proteins. Age had no significant effect. The Bunaji had significantly (P less than 0.05) higher total protein, albumin, and alpha 1-globulin than Friesian X Bunaji. While there was no significant difference in body condition score between the two breeds, the Friesian X Bunaji had a significantly (P less than 0.05) higher growth rate. Animals on high protein diets had significantly (P less than 0.05) higher total protein, albumin, alpha 2-globulin, gamma-globulin and total globulin than those on low protein. However, alpha 1-globulin and beta-globulin were not significantly (P greater than 0.05) different for the two treatment groups.     

Landscape change under indirect effects of human use: the Savanna of Central Chile

The Chilean Intermediate Depression to the north of Santiago has experienced a physiognomical transformation from a Prosopis chilensis woodland to an Acacia caven savanna. Today P. chilensis trees are scarce and belong mostly to the larger size classes. By contrast A. caven seems to reproduce frequently and its populations consist of individuals of all size classes. In this paper we document these changes and report the results of tests aimed at determining the causes of these physiognomical changes. We found that livestock, leporids, introduced Mediterranean forbs and agriculture account for differences in seed dispersal and survival of A. caven and P. chilensis, which can explain the documented changes in the Chilean landscape.     

Skeletal muscle characteristics in young trained and untrained standardbred trotters.

Muscle biopsies were taken from the middle gluteal muscle of 28 Standardbred trotters, 3-4 years of age. The 13 horses in Group T were trained consistently from 18 months of age, whereas the 15 horses in Group UT were not exposed to any systematic training before 3 years of age. Group T horses had a lower percentage of Type IIB fibres (31%) than did Group UT horses (39%). Citrate synthase (CS) activity, representing oxidative capacity, was higher in Group T (72 mmol kg-1 min-1) than in Group UT (47 mmol kg-1 min-1). Biopsies were taken from 4 horses in each group when they were foals and then annually until 3-4 years of age. Results from this study indicate that regular training of Standardbreds from 18 months of age resulted in increased CS activity and a decrease in the percentage of Type IIB fibres. This study shows that training, not growth, is the main factor that induces a high oxidative capacity and a high Type IIA/IIB fibre ratio in muscle of Standardbred trotters.     

Hypothalamic neurotransmitter concentrations and meat quality in stressed pigs offered excess dietary tryptophan and tyrosine.

Pale, soft, exudative (PSE) pork occurs, for the most part, from environmental stress on the pig. Amino acid intake may be related to stress susceptibility through hormone and neurotransmitter induction. Two experiments were conducted to determine whether supplementation of 5 g of tryptophan (TRP) or 10 g of tyrosine (TYR) per kilogram of a 14% CP diet would alter the response of pigs to stress as measured by hypothalamic neurotransmitter concentrations and incidence of PSE. Twenty-four (Exp. 1) and 36 (Exp. 2) 92-kg pigs were offered one of three diets: control, TRP-, or TYR-supplemented for 5 d before slaughter. Dietary TRP or TYR supplementation in Exp. 1. doubled (P less than .05) plasma TRP and TYR concentrations, respectively, and increased (P less than .05) 5-hydroxytryptamine, dihydroxyphenyl ethylamine, dihydroxyphenyl acetic acid, and homovanillic acid concentrations in the hypothalamus. Pigs that exhibited stress at slaughter had lower (P less than .05) hypothalamic concentrations of epinephrine, norepinephrine, and 5-hydroxytryptamine. In Exp. 2, pigs were trucked 55 km to a commercial meat packing facility and slaughtered without a rest period. This handling procedure was designed to invoke a high incidence of PSE pork and thus be a strong test of treatments. Supplemental dietary amino acids seemed to alter the frequency distribution of the severity of PSE pork. These data indicate that dietary manipulation of amino acid precursors of neurotransmitters may offer a practical means of reducing stress response in swine.     

Effect of hot-fat trimming on factors associated with the subprimal yield of beef carcasses.

Thirty-two crossbred cattle (steers = 17; heifers = 15) exhibiting an ultrasound fat thickness at the 12 to 13th rib region of at least 10 mm were selected from a slaughter shift at a commercial packing plant. After splitting, alternating sides of each carcass were trimmed of 1) subcutaneous fat in excess of 6.4 mm; 2) all kidney, pelvic, and heart fat; and 3) all cod or udder fat and fat in the flank region. Both sides of each carcass were fabricated into subprimals (final trim level of 6.4 mm) according to normal industry procedures. Effect of hot-fat trimming, yield grade (3, 4, and 5), and gender on hot-fat trim, fabrication fat trim, major subprimal, and total subprimal yield of untrimmed and trimmed carcasses were determined. Higher numerical yield grade (YG) corresponded with higher (P less than .05) percentages of hot-fat trim. Hot-fat trimming increased (P less than .05) the difference in fabrication fat trim between steers and heifers and between YG 3 and YG 5. Steers and heifers differed (P less than .05) in percentage of major subprimals and total subprimals when processed conventionally, whereas hot-fat trimming eliminated this difference (P less than .05). Untrimmed YG 3 carcasses had 3.1 and 5.0% higher major subprimal yield (P less than .05) than untrimmed YG 4 and YG 5 carcasses, respectively, whereas hot-fat trimming reduced this difference to 2.5% for YG 4 and to 3.7% for YG 5.(ABSTRACT TRUNCATED AT 250 WORDS)