Embryo transfer from goats seropositive for caprine arthritis-encephalitis virus

Twelve attempts were made to isolate caprine arthritis-encephalitis virus (CAEV) from the uterine flushings of serologically positive superovulated does mated to serologically positive bucks. Embryos were transferred to eight serologically negative estrus-synchronized recipient does and the recipients were monitored serologically following embryo transfer. Virus isolation was attempted from colostrum and placental tissues from does that kidded following embryo transfers and the surviving kid was monitored serologically until four months of age. The CAEV was not isolated from any of the uterine flushings, colostrum or placental tissues. All recipients and the kid remained seronegative throughout the trial.     

A kinematic study of crawling behavior in the leech,Hirudo medicinalis

The medicinal leech crawls along a solid substrate by repeated alternating extensions and shortenings of the body. Extension occurs with the posterior sucker attached and the head sucker free. The head sucker then attaches, followed by shortening and release of the tail sucker. The tail sucker is then pulled toward the head, where it reattaches to the substrate. The head sucker then releases, and another crawling cycle begins (Figs. 1, 5). There are two crawling variants: inchworm crawling, in which the head and tail suckers are closely apposed at the end of a cycle and the body forms a loop above the substrate, and vermiform crawling, in which the suckers are placed farther apart and the body remains fairly close to the substrate (Fig. 1). The cycle period and the distance traveled during a cycle are greater in inchworm than in vermiform crawling; however, the velocity of travel is the same for both (Fig. 2). For both variants, the interval between head sucker attachment and tail sucker release is similar at all cycle periods and has a value consistent with direct interneuronal conduction of a signal from head sucker sensory neurons to tail sucker motor neurons. The interval between tail sucker attachment and head sucker release, however, is longer and varies with the cycle period, suggesting a more complex interneuronal circuit in the pathway from tail sucker sensory neurons to head sucker motor neurons (Fig. 4). The onsets of the components of the crawling cycle (extension, post-extension pause, shortening, and post-shortening pause) show an anteroposterior lag (Figs. 5, 7). For both variants, the travel time between segments varies directly with the period (Fig. 8). For both crawl types, the durations of the cycle components vary directly with the period, with several exceptions (Figs. 9, 10). A model is presented that summarizes the coordination of the various motor events in a cycle of leech crawling (Figs. 11 and 12).     

Effects of hormone-induced superovulation on latent infectious bovine rhinotracheitis virus in cattle

Twelve nulliparous, sexually mature heifers free of antibodies to infectious bovine rhinotracheitis (IBR) virus were exposed intranasally to Colorado strain IBR virus. After 3 mos, when the postexposure antibody titers had stabilized, the heifers were divided into three groups. Individuals in each group were treated with either saline, dexamethasone or follicle stimulating hormone (FSH) for five consecutive days. Blood samples were taken at predetermined intervals for isolation of virus, and for determination of serum cortisol levels. No changes occurred in the saline-treated group, except that one heifer had a slightly elevated serum neutralizing antibody titer. Recrudescense of typical clinical lesions was observed in the dexamethasone-treated group, and the IBR virus was isolated from nasal swab samples taken from all heifers. In the FSH-treated group, no changes occurred, with the exception of slightly reduced serum cortisol levels. Results indicate that FSH-induced superovulation does not cause reactivation of IBR virus in heifers previously infected by the intranasal route, and has no effect on serum neutralizing anti-IBR virus antibody titers.     

The economic effect of estrus synchronization in beef heifers on average weaning weight of calves

Prostaglandin was used to induce estrus in 129 Hereford x Holstein heifers for artificial insemination. At the start of the breeding season heifers were observed twice daily and inseminated 12 hours after first being observed in estrus. On the morning of the sixth day of the breeding season all heifers not yet observed in estrus or inseminated were treated with prostaglandin (25 mg Lutalyse(R)). Observation was continued and heifers were bred 12 hours after first observed in estrus. Of the 129 heifers 33 were inseminated before prostaglandin treatment, the remainder of the heifers were bred within 4 days of treatment. Two heifers developed cysts and did not express estrus. First service pregnancy rates were 70% before treatment and 79% after treatment. All heifers were inseminated the first time within the first 10 days of the breeding season and 100 pregnancies occurred in the first 10 days of the season. As a result median days to pregnancy was 8. Calves were all weaned and weighed at approximately 150 days of age. These results were then used to model the economic impact of estrus synchronization of beef heifers on the increased weaning weights of their calves. Prostaglandin treatment altered the distribution of pregnancies and resulted in a cluster of conceptions from Day 7 to 10 of the breeding season with no conceptions from Day 11 to 19. In order to study the influence of estrus synchronization on weaning weights a simulation model was constructed. All heifers that conceived on the first service after prostaglandin were assigned an alternate date of conception from Day 7 to 21 of the breeding season with a random number generator. In this way a uniform random distribution of pregnancies over the first 21 days of the breeding season was constructed. An alternate calving date was then estimated using the known gestation length and this date was used to calculate the weaning weight of the calf using the known weight per day of age. The average weaning weight of the uniform random distribution was then compared to the synchronized distribution with Student's t -test. The simulation model was repeated 10 times and each time weaning weights of the uniform random distribution were significantly less than with the synchronization program (p<.01). At a value of $4.00 for prostaglandin and $1.76 for each kilogram of calf the average increase of 3.8 kgs in weaning weight per calf resulted in a return on investment of $1.92 for every dollar invested in prostaglandin.     

Inhibitory effect of Porphyromonas gingivalis-derived phosphoethanolamine dihydroceramide on acid ceramidase expression in oral squamous cells

The maintenance of diminished acid ceramidase (ASAH1) gene expression leading to the accumulation of antiproliferative intracellular ceramides in oral squamous cell carcinoma (OSCC) has emerged as a prospective oral cancer therapeutic regimen. Our published study demonstrated that the key periodontal pathogen Porphyromonas gingivalis downregulates the expression patterns of ASAH1 mRNA in normal epithelial cells in vitro. Therefore, P. gingivalis may also beneficially diminish the expression of ASAH1 in OSCC. Because a uniquely structured P. gingivalis-derived phosphoethanolamine dihydroceramide (PEDHC) inhibits the proliferation of normal human fibroblasts, this study aimed to test the effect of PEDHC on the survival of human oral squamous OECM-1 cells in vitro. We demonstrated that the P. gingivalis dihydroceramide-null (ΔPG1780) strain upregulates the expression of ASAH1 mRNA and promotes aggressive proliferation and migration of OECM-1 cells compared to the parent P. gingivalis-W83 strain. In addition, the intracellular concentration of ceramides was dramatically elevated in OECM-1 cells exposed to PEDHC in vitro. Furthermore, PEDHC inhibited expression patterns of ASAH1 mRNA as well as some genes associated with degradation of the basement membranes and extracellular matrix, for example, MMP-2, ADAM-17 and IL-6, in OECM-1 cells. Altogether, these data indicated that PEDHC produced by P. gingivalis inhibits acid ceramidase expression, promotes intracellular ceramide accumulation and suppresses the survival and migration of OSCC cells in vitro. Further studies are needed to determine molecular mechanisms of PEDHC-mediated inhibitory effect(s) on OSCC using in vivo models of oral cancer.     

New RFLPs of the immunoglobulin switch alpha region in mesangial IgA glomerulonephritis

Summary New alleles of the human immunoglobulin switch alpha region are described in patients with mesangial IgA glomerulonephritis.     

Interactions between Meloidogyne incognita,M. hapla,and Pratylenchus brachyurus in Tobacco

In a greenhouse pot experiment on the pathogenicity and interactions of Meloidogyne incognita, M. hapla and Pratylenchus brachyurus on four cultivars o f tobacco the cultivars ''Hicks'' and ''NC 2326'' were susceptible to each nematode and "NC 95'' and ''NC 2512'' resistant only to M. incognita.Mean heights of susceptible plants were depressed but fresh weight of tops did not differ significantly. Meloidogyne spp. increased fresh weight of susceptible (but not the resistant) roots.Reproduction of M. incognita was decreased in the presence of P. brachyurus in one case. M. hapla reproduction was less with either of the other nematodes in five out of eight cases. In 12 combinations involving P. brachyurus, reproduction of this species was depressed in seven, not affected in four and increased in one.Mechanisms involved in associative interactions were not identified but appeared to be indirect and to involve individual host-nematode responses.     

Seasonal Population Dynamics of Selected Plant-parasitic Nematodes as Measured by Three Extraction Procedures

Seasonal fluctuations in field populations of Meloidogyne spp. (M. incognita and M. hapla), Pratylenchus zeae, Criconemoides ornatum, Tylenchorhynchus claytoni, Belonolaimus longicaudatus, and Helicotylenchus dihystera were determined monthly for 1 year by three extraction procedures. Baermann funnel method (BF) gave highest recoveries of Meloidogyne spp. and P. zeae during summer and fall, but centrifugal-flotation (CF) and sugar-flotation-sieving (SFS) usually yielded higher numbers of these nematodes during winter and spring. CF was t h e only effective method for recovery of C. ornatum with maximum numbers occurring in September. Recoveries of T. claytoni were similar with all methods in summer and fall. However, BF gave low numbers in winter and spring, whereas population peaks with the flotation methods occurred in January and February. All methods gave similar recoveries of B. longicaudatus with highest numbers occurring in November and December. This species declined drastically in late winter and spring. Yields of H. dihystera were similar for all three methods with CF consistently higher and the major peaks occurring in August.