Increased postnatal growth rates of offspring after antiestrogen treatment of rat dams during pregnancy.

The effects of administration of estradiol antiserum to pregnant rats on birth weight, subsequent growth velocity, carcass composition, and reproductive performance of their offspring were examined. Treated rats were injected i.p. with a potent antiestradiol serum on d 12 of gestation, whereas control rats received a similar injection of normal sheep serum. The pups from the treated rats were 12.2% heavier at birth than those from control rats (P less than .01) and had a greater postnatal growth rate (P less than .05). Chemical analysis of body composition at 56 d of age revealed that there was a tendency for female offspring from treated rats to exhibit carcass characteristics (such as increased percentage of body fat) that were more similar to those of normal male rats than to those of normal female rats. Neither onset of puberty nor reproductive performance was affected by the treatment. These results indicate that treatment of rats during pregnancy with antiestradiol may have potential as a technique for increasing postnatal growth rates.     

ULTRASONOGRAPHIC EVALUATION OF THE FETUS AND INTRAUTERINE ENVIRONMENT IN HEALTHY MARES DURING LATE GESTATION

Mares with uncomplicated pregnancies (n = 33) underwent transabdominal sonography to evaluate fetal well-being, obtain measurements of fetal size and characterize the intrauterine environment. Data from the last examination obtained prior to parturition were used for statistical analysis. All mares had one active fetus with good fetal tone. The maximal vertical depth of amniotic fluid (7.9 ± 3.5 cm) was less than allantoic (13.4 ± 4.4 cm) and fewer echogenic particles were detected in amniotic fluid. The maximal uteroplacental thickness was 1.38 ± 0.23 cm (retrospective) and 1.15 ±± 0.24 cm (propspective). In 3 mares small anechoic spaces were imaged between the uterus and placenta. Fetuses had a regular cardiac rhythm with a mean heart rate of 75 ± 7 beats/minute and breathing movements. The diameter of the fetal aorta (mean = 22.8 ± 2.15 mm) was significantly correlated with neonatal foal weight (P<0.0008, r = 0.72) and maternal prepartum weight (P<0.002, r = 0.86). This information of the normal intrauterine environment and fetal well-being can be used to develop a biophysical profile specific for the equine fetus.     

RADIATION EXPOSURE DURING EQUINE RADIOGRAPHY

All personnel present in the X-ray examination room during equine radiography were monitored using low energy direct reading ionization chambers (pockets dosimeters) worn outside the lead apron at neck level. The individuals' task and dosimeter readings were recorded after each examination. Average doses ranged from 0 to 6 mrad per study. The greatest exposures were associated with radiography of the shoulder and averaged less than 4 mrad. The individual extending the horse's limb was at greatest risk although the individual holding the horse's halter and the one making the X-ray exposure received similar exposures.
A survey of the overhead tube assembly used for some of the X-ray examinations also was performed. Meter readings obtained indicated an asymetric dose distribution around the tube assembly, with the highest dose occurring on the side to which the exposure cord was attached.
Although the exposures observed were within acceptable limits for occupational workers, we have altered our protocol and no longer radiograph the equine shoulder unless the horse is anesthetized. Continued use of the pocket dosimeters and maintenance of a case record of radiation exposure appears to make the technologists more aware of radiation hazards.     

Distribution of lymphoid leukosis virus and p27 group-specific antigen in tissues from laying hens

In order to gain insight into transmission and pathogenesis of infection, specimens from laying hens that had been naturally exposed to lymphoid leukosis virus (LLV) were tested for group-specific antigen (gsa) of the virus by immunofluorescence (IF), complement fixation (CF), and the enzyme-linked immunosorbant assay (ELISA). Electron microscopic examinations determined the distribution of C-type virus particles in tissues, and the phenotypic-mixing test served as a biological assay for exogenous LLV. The IF gsa was found in all organs tested, and fluorescence was usually found where virus particles were concentrated. In the oviduct and intestine, IF gsa was frequently at the border of the lumina and in the connective tissue associated with basal membranes of glands. In skin, the antigen was detected in smooth muscle, in feather pulp, and in basal epidermal cells of developing feathers. Results of various tests on Ottawa strains of chickens were usually in agreement. For example, among hens that shed gsa into egg albumen, only the viremic hens were consistently positive for IF gsa in both spleens and oviducts. Geometric mean CF titers of antigen were respectively five- and 23-fold higher in spleens and oviducts from viremic hens than in those from nonviremic hens. These findings suggest that the gsa was associated with exogenous virus infection. In Cornell S strain hens that had not been exposed to LLV, gsa was detected in splenic tissue by CF and ELISA but not by the IF test. This gsa was presumed to be of endogenous origin.     

Reproductive toxicity in pseudopregnant and pregnant rats following postimplantational exposure: Effects of the herbicide dinoseb

In Day 10 decidualized pseudopregnant rats fed dinoseb in the diet from Days 6 through 9 of pseudopregnancy, uterine wet weight was reduced in the groups fed 100 to 750 ppm (the highest dose tested). Uterine protein and glycogen concentrations in these animals were reduced in a dose-related manner. In Day 16 pregnant rats, orally fed dinoseb from Days 6 through 15 of pregnancy, placental protein and glycogen concentrations were diminished at 200 ppm and greater. Pregnant rats fed dinoseb (Days 6–16) showed reductions in their embryonic survival rates at 200 ppm and greater. The fetal survival rates at birth, from pregnant rats which were similarly administered dinoseb, were reduced at 150 ppm and greater. Fetal weight of fetuses from dams given dinoseb (200 ppm) was diminished. These results from decidualized pseudopregnant and pregnant rats indicate a toxic role for dinoseb in the intrauterine environment. This toxicity is apparently responsible for a decline in fertility in pregnant rats. Moreover, 200 ppm dinoseb seems to be reproductively critical.     

Evaluation of aerobic bacteriologic culture of epidermal collarette specimens in dogs with superficial pyoderma

OBJECTIVE: To evaluate a method of aerobic bacteriologic culture of epidermal collarette specimens from dogs with superficial pyoderma and compare results with those for aerobic bacteriologic culture of abdominal skin specimens in healthy dogs. DESIGN: Prospective study. ANIMALS: 22 dogs with epidermal collarettes and 24 healthy dogs. PROCEDURE: Dry sterile cotton swabs were rolled across epidermal collarettes or hairless areas of abdominal skin in healthy dogs and submitted for aerobic bacteriologic culture. Hemolytic colonies of gram-positive-staining cocci were tested for catalase production, and if results were positive, a coagulase test was performed. Colonies with coagulase activity were tested for the ability to ferment mannitol. Antimicrobial susceptibility testing was performed on all Staphylococcus spp that were isolated. RESULTS: S. intermedius was isolated from collarettes in 18 of 22 dogs with superficial pyoderma but not from healthy dogs. Estimated sensitivity and specificity of the culture method were 81.8% and 100%, respectively. There were no significant differences in the ability to culture S. intermedius, the number of S. intermedius isolates without resistance to antimicrobials, and the number of S. intermedius isolates resistant to penicillin G when comparing dogs with superficial pyoderma for the first time and dogs with recurrent pyoderma, dogs that did or did not receive concurrent antimicrobials, and dogs with and without underlying allergic disease. CONCLUSIONS AND CLINICAL RELEVANCE: Bacteriologic culture of epidermal collarette specimens was a simple and reliable method for identification of S. intermedius in dogs with superficial pyoderma, regardless of history of pyoderma or current antimicrobial use.     

Neospora caninum: adoptive transfer of immune lymphocytes precipitates disease in BALB/c mice

Neospora caninum is a recently described apicomplexan parasite first isolated from a dog in 1988 and has subsequently been shown to infect a wide range of mammals. In mice, Neospora can cause primary pneumonia, myositis, encephalitis, radiculoneuritis, and pancreatitis. Whereas, certain aspects of the host immune response to Toxoplasma gondii have been well studied, not as much is known about the full immune response to Neospora. This paper examines whether or not immune splenocytes are able to adoptively transfer protection against N. caninum infection in BALB/c mice. Mice receiving immune enriched CD8+ cells had severe neurological signs by 19 days post infection. Mice receiving immune enriched CD4+ cells had mild neurological signs on day 22 post infection. It would appear that additional immune cells can precipitate disease in the presence of circulating lymphocytes.