Characterization of endotoxin from the rumen bacterium Megasphaera elsdenii.

Phenol-water extraction of Megasphaera elsdenii, a predominant gram-negative coccus in rumens of cattle fed high-grain diets, yielded material that exhibited typical characteristics of endotoxin. The extract was lethal to mice and to chicken embryos, caused biphasic fever in rabbits, leukopenia in mice, and local and generalized Shwartzman reactions; and induced tolerance to the lethal effect of the endotoxin in mice. The material contained carbohydrate, protein, lipid, phosphorus, and 2-keto-3-deoxyoctonate, but no nucleic acid. The beta-hydroxymyristic acid was absent. Results imply that M elsdenii endotoxin has many biological and chemical characteristics common to enterobacterial endotoxin. However, the median lethal doses in mice and in chicken embryos, and minimal dose required to elicit a local Shwartzman reaction, indicate that M elsdenii endotoxin's potency is low, which may explain why the large gram-negative bacterial population in the rumen of cattle is generally innocuous.     

Fertility in buffaloes after oestrus synchronisation with cloprostenol and fixed time insemination.

Fifty-seven cycling buffalo cows of the river type were treated with two doses of 0.5 mg cloprostenol intramuscularly given 11 days apart. Each animal was inseminated twice at 72 and 96 hours after the second injection of cloprostenol. The first service conception rate diagnosed by rectal palpation at 90 days was 38.6 per cent. At the time of insemination the cervix was easily penetrable on both days in only 39 (68.4 per cent) of the animals. They were inseminated at or beyond the internal cervical os, while the others were inseminated in the cervical canal. There was a marked difference in conception rate between those receiving deep inseminations (48.7 per cent) and the others (16.7 per cent). In relation to the interval from calving to insemination the conception rates for those which had calved 60 to 90, 90 to 120 and 120 to 150 days earlier were 16.6, 36.4 and 55.5 per cent respectively. The use of cloprostenol treatment and fixed-time insemination is a useful method of overcoming the problem of oestrus detection in buffaloes. Acceptable levels of fertility can be obtained in those animals which have a sufficiently relaxed cervix to permit semen deposition at the internal os, provided the interval from calving to insemination is more than 90 days.     

Age-related variations in cortical bone-remodeling measurements in male Beagles 10 to 26 months of age.

Age-related variations in bone-remodeling rates in the male Beagle were unknown. Variations were examined in 28 male Beagles whose ages were evenly distributed between 10 and 26 months. Results were analyzed by computer and regression lines for a best fit line for each determination were given; the 95% confidence limit for the best-fit line and the 95% confidence limits for the individual measurements were calculated. The results are graphically presented in this paper. There was a slight increase in total cortical area, although there was a decrease in the ratio of total-to-cortical area. Osteoid seams showed a frank decrease. Relatively little variation was found in circumference of osteoid seams and appositional rate. The number of resorption spaces decreased. There was a decrease in radial closure rate. Marked decreases were found in activation frequencies and bone formation rate. Increases were observed in osteon formation times and ratio of resorption to formation. The width of osteoid seams and the percentage of systems labeled decreased slightly. As a result of these experiments concerning variations in bone-remodeling activity carried out on Beagles (using the same dogs as their own controls), it was concluded that results obtained should be compared with the expected age-related activity of bone remodeling and not with the initial preexperimental biopsy results.     

Pyometra in the dog. III.--A pathophysiological investigation. III. Plasma progesterone levels and ovarian morphology.

The peripheral plasma progesterone levels in bitches with spontaneously developed pyometra did not differ significantly from those in normally cycling or pregnant bitches. The macroscopic ovarian morphology gave no indication of an increased corpus luteum activity. Ovarian follicular cysts were found in 4 out of 31 cases. There was no detectable difference of results between 14 bitches that had received hormonal medication 10 years to 1 week previous to the pyometra diagnosis, and the other patients.     

Nephrogenic diabetes insipidus in a dog with renal medullary lesions.

Antidiuretic hormone (ADH) administration to a polyuric Miniature Poodle did not alter diuresis. Plasma ADH concentrations were high, and urine osmolality remained low during water deprivation. From these findings, it was concluded that the polyuria was of renal origin. In addition, the glomerular filtration rate was found to be high. Electron microscopic examination of the renal medulla revealed vacuoles containing myelinic figures and fingerprint structures in the cells of the Henle loops, blood vessels, and interstitium, similar to those in lysosomal lipid storage disease. Their absence in collecting duct epithelium indicated that the defect in concentrating ability was due to a disturbance of the counter-current multiplier mechanism rather than to a defect in ADH receptors.     

Metabolism of colostomized laying hens with 15N-labeled wheat. 3. Incorporation of 15N into and its distribution over follicles of various stages of development, the restovar and the oviduct

Of colostomised hens fed with labelled wheat protein the atom-% 15N-excess (15N') was ascertained in the bigger follicles, the restovar and the oviduct from the total N, the lysine-N, histidine-N and arginine-N. The labelling of the basic amino acids decreases the smaller the follicles are. In contrast to the yolk, in which a constant relation between the three amino acids was found, the relations were inconsistent and typical of the individual hens. In the atom-% 15N' in the three amino acids in the restovar and the oviduct there were greater differences between the hens. In the lysine, histidine and arginine we found, on an average, 21.2% of the total labelled N of the follicles.     

Acute viral hepatitis in California sea lions

Acute viral hepatitis was diagnosed in five California sea lions (Zalophus californianus) stranded along the Los Angeles coast. Light microscopy revealed large nuclear inclusion bodies in hepatocytes. Electron microscopy provided evidence that these inclusion bodies were composed of adenovirus-like virions. Attempts to grow the virus in cell culture systems were unsuccessful.     

Further studies with a sex-linked lethal gene in the fowl

1. The ladykiller (lk) gene has been located on the sex chromosome of the fowl. It is 4.2 map units distant from the feathering rate locus (k) and 11.2 map units distant from the dwarf (dw) locus. 2. Most of the embryonic mortalities associated with this gene occurred between 3 and 4 d of incubation.