Synthesis, transport, and release of posterior pituitary hormones

Vasopressin and oxytocin are made and released by neurons of the hypothalamo-neurohypophysial system. Pulse labeling these neurons with radioactive amino acid indicates that the two hormones and their respective neurophysin carrier proteins are synthesized as parts of separate precursor proteins. The precursors seem to be processed into smaller, biologically active molecules while they are being transported along the axon.     

Cross-reacting antigens between Mycoplasma ovipneumoniae and other species of mycoplasma of animal origin, shown by ELISA and immunoblotting with reference antisera

Using enzyme-linked immunosorbent assays with Mycoplasma ovipneumoniae as antigen, the cross-reactivity of antigens between this species and 22 other mycoplasma species was examined using reference polyclonal antisera. Significant cross-reactivity with M. ovipneumoniae was demonstrated by five species, only, viz. M. bovoculi, M. dispar, M. flocculare, M. hyopneumoniae and M. hyorhinis. Using one-dimensional SDS-PAGE and immunoblotting techniques with homologous and heterologous antisera, cross-reacting antigens of M. dispar, M. flocculare, M. hyopneumoniae and M. ovipneumoniae were further investigated. Cross-reacting antigens with apparent molecular weights of 64, 44 and 32 kDa were common to all and a 184 kDa cross-reacting antigen occurred in all except M. ovipneumoniae. Further cross-reacting antigens (one-way and two-way) between two of the four species are reported. Four monoclonal antibodies against different antigens of M. ovipneumoniae did not recognise any antigen in the other three species examined.     

Effect of meal schedules and fasting on selected plasma free amino acids in horses

The effects of meal frequency and fasting on selected plasma free amino acids (PFAA) was studied in horses. Six 22-mo-old Quarter Horses were used in a replicated 3 X 3 Latin-square design in which each horse received one meal per day (1M), two meals per day (2M) or six meals per day (6M) for 2 wk. A complete pelleted ration was fed at a rate of 1.75% of body weight daily. The consumption of a meal by the horses fed 1M and 2M daily was followed by an increase (P less than .05) in plasma methionine. The highest levels were observed at 5 h and 3 h in the 1M and 2M treatments, respectively. The horses receiving the larger meal (1M) also had higher methionine levels. There were no significant changes in plasma methionine levels in the 6M group. Feed was withheld from the 1M group for 48 h and blood samples were obtained for alanine, glutamine, glutamate, lysine and leucine levels. These amino acids also peaked at 5 h, then declined through 19 to 25 h. During the last 24 h PFAA levels increased (P less than .05). Although glutamine and lysine appeared to level off at 49 h after the meal, alanine, glutamate and leucine were still increasing.     

Characterization of infectious laryngotracheitis viruses, antigenic comparison by kinetics of neutralization and immunization studies.

Five isolates of infectious laryngotracheitis virus were compared by pock formation on the chorioallantoic membrane of embryonated eggs, plaque size in chicken embryo kidney tissue culture, and antigenic relationship using reciprocal kinetics of neutralization. The A4557-5 strain of infectious laryngotracheitis virus, which causes mild respiratory disease, produced pocks with a zone of edema on the chorioallantoic membrane. A virulent virus (Virus 1), isolated from an outbreak of severe disease characterized by a diphtheritic laryngotracheitis, produced the largest plaques in chicken embryo kidney cell culture. Other virulent viruses (Viruses 2, 3 and V154) did not have unique growth characteristics when grown on the chorioallantoic membrane or in chicken embryo kidney cell culture. All viruses were closely related antigenically as shown by kinetics of neutralization but viruses 2 and 3 were not homogeneous with the other three viruses when neutralized by anti-V154 chicken serum. Following aerosol infection, chickens infected with the A4557-5 virus were immune to challenge with virulent V154 virus. However, in comparison to SA-2 virus, this virus was a less effective immunizing agent when administered by the vent or drinking water methods.     

A stochastic simulation model for evaluating forage machinery performance

The selection of machinery on a dairy farm is the focus of the study. A simulation model is constructed that evaluates alternative forage machinery complements on New York State dairy farms. Attention is focussed on the machinery use, forage crop production and concentrate purchase. The key measure of performance is the total cost of acquiring feed for the dairy herd. The total cost includes the machinery investment and operating costs and the cost of feeds required to supplement that produced on the farm.The simulation model, written in Fortran, utilises a daily timestep. Each day the feasibility of machinery operation is determined, machinery operations are scheduled and the end of day status is determined.     

Single step purification procedure for the rapid separation of equine leucocytes

Percoll gradients have been used to separate relatively pure populations of viable equine polymorphonuclear (PMN) and mononuclear (MN) cells. In preliminary studies, a continuous density gradient of 70% Percoll solution was used to separate two distinct leucocyte-rich bands. After measurement of the density of each band on the continuous gradient, discontinuous Percoll gradients, using 60% and 75% Percoll solutions, were used to provide a rapid means of separating PMN and MN cells. The yield of viable cells per ml of blood was 3.0 X 10(6) and 3.2 X 10(6) for MN and PMN cells, respectively. Corresponding values for recovery were 45% and 72%. The purity was 94% for PMNs and 99% for MNs.     

Pneumatosis coli in a dog

A 17-year-old, castrated male Maltese was presented with chronic polyphagia and a 2-week history of tenesmus, diarrhea, hematochezia, weight loss, and ribbon-like feces. Pneumatosis coli was diagnosed by abdominal radiography. Concurrent hyperadrenocorticism was suspected. The clinical signs of colorectal disease resolved within 2 days of initiating a lowresidue diet and oral metronidazole. Pneumatosis coli should be considered as a differential diagnosis for colorectal disease in dogs.