Pilot study of the effect of acemannan in cats infected with feline immunodeficiency virus.

Acemannan, a complex carbohydrate shown to stimulate interleukin-1, tumor necrosis factor alpha and prostaglandin E2 production by macrophages, has also demonstrated antiviral activity in vitro against human immunodeficiency virus, Newcastle disease virus and influenza virus. A pilot study was undertaken to determine acemannan's effect in 49 feline immunodeficiency virus (FIV) infected cats with clinical signs of disease (Stage 3, 4 or 5), 23 of which had severe lymphopenia. Cats received acemannan either by intravenous (Group 1) or subcutaneous (Group 2) injection once weekly for 12 weeks, or by daily oral (Group 3) administration for 12 weeks. Upon entry into the study, cats were randomly assigned to one of the three groups. Laboratory analyses were performed at the beginning of the study and at Weeks 6 and 12. Cats were allowed to continue with a predetermined maintenance regimen of acemannan after completing the 12-week study. Thirteen cats died during the course of treatment. Upon necropsy, the most frequent histopathologic findings were neoplastic, kidney and pancreatic disease. Friedman's two-way ANOVA test showed no significant differences in efficacy among groups administered acemannan by the different routes. Therefore, groups were combined and a signed-ranks test was used to determine changes over time. A significant increase was seen in lymphocyte counts (P < 0.001). Neutrophil counts decreased significantly (P = 0.007), as did incidence of sepsis (P = 0.008). When cats entering with lymphopenia were analyzed separately, a much greater increase in lymphocyte counts was noted (235%) compared with non-lymphopenic cats (42%). A survival rate of 75% was found for all three groups. Thirty-six of 49 animals are alive 5-19 months post-entry. These results suggest that acemannan therapy may be of significant benefit in FIV-infected cats exhibiting clinical signs of disease.     

Additive and synergistic pharmacologic inhibition of equine fibrinoligase (factor XIIIa*-like) biochemical activity.

A selected group of pharmaceutical compounds were evaluated for the ability to inhibit the biochemical activity of fibrinoligase (coagulation factor XIIIa*) in pooled equine plasma. Criteria for the pharmaceuticals selected were based on the mechanism of the transglutamination biochemical reaction mediated by coagulation factor XIIa*. These criteria were complemented by recognition of the molecular configuration and chemical composition of amino acid residue side chains involved in the process of covalent fibrin monomer polymerization (cross-linking, transglutamination) mediated by this enzyme. Each pharmaceutical was evaluated individually and in combination with other potential coagulation factor XIIIa* inhibitors in an effort to detect additive and synergistic phenomenon. In this context, pharmaceuticals with a carbonylamide (eg, cefuroxime, Girard's reagent-P, prolinamide) were applied in concert with compounds with a terminal amine (eg, D-arginine, L-lysine) functional group. In concept, this method theoretically served to competitively simulate glutamine and lysine amino acid residues within strands of fibrin monomer substrate involved in phase I (carbonylamide) and phase II (terminal amine) of the transglutamination reaction (covalent fibrin monomer cross-linking). Halogen-dinitro and ethylene compounds were also evaluated because of their reported ability to inactivate enzyme systems dependent on an intact sulfhydryl group located at their biochemically active site (eg, cystine amino acid residue). This group of pharmaceutical compounds failed to inhibit the biochemical activity mediated by coagulation factor XIIIa* in equine plasma.     

Evaluation of a monoclonal blocking ELISA and IHA for antibodies to Mycoplasma hyopneumoniae in SPF-pig herds.

A monoclonal blocking enzyme-linked immunosorbent assay (ELISA) and an indirect haemagglutination assay (IHA) were applied to serum samples from 124 specific pathogen-free (SPF) breeding and multiplying herds, which participate in the routine serological surveillance of the Danish SPF programme. Clinical and pathological observations of the herds and microbiological culturing of Mycoplasma hyopneumoniae were used to calculate herd sensitivity, herd specificity and herd predictive values for the two serological assays. The ELISA was superior to the IHA in herd sensitivity and herd specificity, with values of 93 per cent and 96 per cent, respectively, for the ELISA, and 61 per cent and 92 per cent for the IHA. During the six month period of evaluation 2.5 per cent of the herds were infected with M hyopneumoniae each month. At this level the IHA was found to have a positive herd predictive value of 16 per cent, compared with 39 per cent for the ELISA. The negative herd-predictive value on the same level was 99.8 per cent for the ELISA and 98.9 per cent for the IHA. If the assays were applied to a group of herds with a herd prevalence of M hyopneumoniae infection of 30 per cent (as is the case with the production herds in the Danish SPF programme) the predictive value of a positive herd diagnosis would be 91 per cent for the ELISA and 76 per cent for the IHA, and the predictive value of a negative herd diagnosis would be 97 per cent with the ELISA and 85 per cent with the IHA.(ABSTRACT TRUNCATED AT 250 WORDS)     

Light and electron microscopic studies of calf kidneys after exposure to subtoxic lead levels]

Eight calves were fed from the fourth to the twentieth week of age a milk powder diet containing 40 mg lead acetate per kg dry substance. This is twice the lead concentration legally permitted. In average, each animal has daily taken up 0.834 mg lead per kg body weight. Eight calves were used as controls. The animals gained the usual fattening weights and did not show clinical symptoms. Beginning with week 14, increased levels of blood urea were encountered in the animals which received lead in their diet. Morphologically, severe renal lesions were found in these calves. The kidneys were increased in weight, pale and of firm consistency. Histologically, fibrosis and periglomerular interstitial non-purulent nephritis were found. Light- and electronmicroscopically, numerous intranuclear inclusion-bodies typical for lead poisoning were demonstrated in epithelial cells of proximal tubules. The results show, that daily uptake of less than 1 mg lead per kg body weight must be considered as a toxic dose for calves, and not 5-7 mg as stated in literature.     

Variance decomposition in the estimation of genetic variance with selected data.

Estimation of genetic variance in populations under selection involves assumptions on base animals. Base animals are often considered unselected and it also has been proposed to treat selected base animals as fixed. The consequences of assumptions on base animals in the estimation of genetic variance in selected populations are not fully understood. Variance decompositions are introduced for simple designs to quantify the differences between models that treat base animals in different ways. Independent contrasts were constructed and REML estimates of variance components were compared for different designs and selection rules. The method shows how selection is accounted for in a complete model and why estimation of variance components can become biased when base animals are treated as fixed.     

Effect of diet on results obtained by use of two commercial test kits for detection of occult blood in feces of dogs.

To evaluate the effect of diet on results obtained by use of 2 commercial test kits for detection of occult blood in feces, 5 dogs were fed 7 diets in randomized sequence. Dry and canned diets with various principal ingredients were evaluated. Each diet was offered twice over a 24-hour period, followed by a 36-hour nonfeeding period. Fecal specimens were collected twice daily, and tests for occult blood were performed within 12 hours. The dietary origin of fecal specimens was confirmed by use of colored markers fed with each diet, and was correlated with estimates of gastrointestinal tract transit time. A modified guaiac paper test and an o-tolidine tablet test were performed on each specimen. Of 59 specimens, 4 were positive for occult blood, using the o-tolidine tablet test. Three positive results were associated with a mutton-based canned diet, and 1 positive result was associated with a canned beef-based diet. Of 59 specimens, 11 were positive for occult blood, using the modified guaiac paper test. Four positive results were associated with the mutton diet, and 3 positive results were associated with the beef diet. Of the remaining 5 diets, 4 caused 1 positive reaction. Results were inconsistent with the null hypothesis that the distribution of positive occult blood test results is not affected by diet (P < 0.025), and indicate that diet can affect the specificity of peroxidase-based tests for detection of occult blood in canine feces. Diet modification prior to testing is recommended.     

Variability of serum bile acid concentrations over time in dairy cattle, and effect of feed deprivation on the variability.

Twelve nonlactating dairy cows, free of signs of liver disease and with normal serum activities of liver-derived enzymes and normal liver biopsy tissue, were examined over a 72-hour period for serum total bile acid concentrations. The cattle were fed hay twice daily, and blood samples were obtained every hour for 24 hours, every other hour for 24 hours, then every hour for 24 hours. After 3 weeks, the study was repeated on 6 of the cattle, thus providing data for eighteen 72-hour periods. Serum bile acid concentration varied greatly over the 72 hours, with the range being from one third to 3 times the median. There were variations by as much as 60 mumol/L from 1 hour to the next. After another 3 weeks, 8 of the cattle were deprived of hay for 48 hours and then fed hay morning and afternoon of the third (last) day of the study. There was no significant reduction in bile acid concentration after withholding the hay, but the variability was reduced (P = 0.02) during the last 20 hours of the hay-deprivation period. In 3 ancillary studies, serum bile acid concentrations were examined over a 48-hour period in 2 cows in early lactation, 3 cows in midlactation, and two 6-month-old heifers. The cows were fed hay and grain twice daily, and the heifers were fed only hay twice daily. In comparison with values for the 12 nonlactating cows fed hay twice daily, mean serum bile acid concentration in the recently freshened cows was significantly (P < 0.002) higher (62.9 vs 22.0 mumol/L).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of breed and retained heterosis on milk yield and 200-day weight in advanced generations of composite populations of beef cattle.

Retained heterosis in F2 cows nursing F3 progeny was evaluated in 3-, 4-, and greater than or equal to 5-yr-old cows. Traits evaluated included milk yield at three stages of lactation and 200-d weight of progeny. Breed effects were evaluated in the nine parental breeds (Red Poll [R], Hereford [H], Angus [A], Limousin [L], Braunvieh [B], Pinzgauer [P], Gelbvieh [G], Simmental [S], and Charolais [C]) that contributed to the three composite populations (MARC I = 1/4 B, 1/4 C, 1/4 L, 1/8 H, 1/8 A; MARC II = 1/4 G, 1/4 S, 1/4 H, 1/4 A; and MARC III = 1/4 R, 1/4 P, 1/4 H, 1/4 A). Breed effects were significant for 12-h milk yield, estimated 200-d milk yield, and 200-d weight of progeny. Herefords were lowest (P less than .05) for 12-h milk yield and estimated 200-d milk yield, and Braunvieh produced significantly more milk than all breed groups except Pinzgauer and Simmental, for which the difference approached significance. The correlation among breed group means (nine parental breeds and three composites) for 12-h milk yield with 200-d weight of progeny was .91. When 200-d weight was adjusted to a common estimated 200-d milk yield, Hereford, Angus, Red Poll, and Limousin did not differ (P greater than .05); all were significantly lighter than Braunvieh, Pinzgauer, Gelbvieh, Simmental, and Charolais, which did not differ (P greater than .05) from each other.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of dietary molybdenum on nematode and host during Haemonchus contortus infection in lambs.

The addition of molybdenum (0.05 mmol kg-1 dry-matter) to the diet of lambs given a trickle infection of Haemonchus contortus larvae (500 third stage larvae d-1 over six weeks) reduced mean faecal egg counts (epg) from 3952 to 2312 +/- 402 by 32 days (P less than 0.02) and greatly reduced the mean number of worms recovered from the abomasum 14 days after infection ceased (907 compared with 4167: P less than 0.01). Infection reduced haemoglobin concentrations less in lambs given molybdenum although the difference was small relative to the reduction in worm burden. Lambs not given molybdenum had low intraepithelial mast cell counts in the abomasal mucosa and less abomasal hypertrophy than expected from abomasal parasitism. Molybdenum did not consistently reduce the copper status of the host or the parasite. Previous exposure to molybdenum greatly reduced protein but not proteinase activity in, or secreted by, adult worms cultured for eight hours. It is suggested that molybdenum either increased the inflammatory response which preceded worm rejection or that it indirectly enhanced that reaction by reducing the effectiveness of copper-dependent, anti-inflammatory enzymes in the gastrointestinal mucosa.