Acute infection of encephalomyocarditis (EMC) virus in Syrian hamsters.

One-month-old Syrian hamsters of the APA and Std: golden strains were inoculated intraperitoneally with 10(5) PFU/head of the D variant of encephalomyocarditis (EMC) virus and examined virologically and pathologically up to 7 days after inoculation. APA hamsters developed apparent hyperglycemia due to pancreatic islet cell damage while Std:golden hamsters did not. Hamsters of both strains showed clear histopathologic changes in the testis with prominent viral replication as well as in the brain, heart and exocrine pancreas. The susceptibility to EMC virus-infection was higher in males than in females and in APA than in Std: golden hamsters.     

Association between solar radiation and ocular squamous cell carcinoma in cattle

The association between ocular squamous cell tumors and various measures of solar radiation was evaluated for 2,775 contemporaneous Hereford cattle. The animals were from 34 herds located in 21 states in the United States and in one Canadian province. Examinations and photographs were made of the eyes of all cows and heifers in a herd; 33 herds were examined between June and August 1957 and 1 herd was examined in 1958. Solar radiation was measured by altitude and mean annual hours of sunshine applying to an individual herd, and global radiation, a cloudiness index, and elevation of nearby National Weather Service stations. All measures of solar radiation provided evidence of a significant association between increasing risks of developing cancer eye and increasing levels of radiation; adjustments were made for possible confounding effects of age and corneoscleral pigmentation. Associations were evident whether affliction was defined as the occurrence of any type of tumor (ie, plaque, papilloma, or carcinoma), or as the occurrence of only papilloma or carcinoma. Average ages of affected cattle also tended to be lower at high radiation levels than at low levels, further supporting the hypothesis that solar radiation has an important role in the development of this disease. In view of the heritability of eye pigmentation and its inhibitory effect on lesions, cancer eye may be controlled by selective breeding for increased pigmentation in and around the eye to afford protection against the harmful effects of incident UV radiation.     

Isolation and purification of a diagnostic antigen for bovine cysticercosis by hydrophobic chromatography

An ammonium sulfate fraction of Taenia hydatigena cyst fluid (ThFAS) was further fractionated by hydrophobic interaction chromatography, using alkylagarose and omega-amino alkylagarose columns, in an effort to isolate and purify a specific diagnostic antigen in the ThFAS preparation. The less than 12 kDa antigen was found to have an affinity for immobilized alkanes with chain length of six carbons or greater. The antigen was recovered in an ethylene glycol eluate from a hexylagarose column then analyzed by Western blot; it reacted with bovine and human cysticercosis infection sera and with specific monoclonal antibodies but not with control sera or fascioliasis infection sera. When the eluate was used as coating antigen in a plate ELISA assay no false positive reactions were seen in sera from cattle infected with Fasciola hepatica; false positive reactions were observed for the unfractionated ThFAS antigen preparation.     

Accuracy of the thermodilution method in estimating high flow - an in vitro study

The accuracy of thermodilution for measuring flow rates of 10–40 L/min was evaluated using a commercially available thermodilution cardiac output computer in an in vitro model. Water (36.5–37.5°C) was directed through a mixing chamber via a constant flow pump. Thermodilution estimates of flow using four different volumes (10, 20, 30, 40 ml) of iced water injectate were compared to simultaneous measurements of timed samples of effluent from the mixing chamber. Injectate volume had a significant impact on the accuracy of thermodilution estimation (p < 0.05). Thermodilution overestimated measured flow when 10 and 20 ml of injectate were used to determine flow rates < 20 L/min but underestimated flow when injectate volumes of 30 and 40 ml were used, or when measured flow was > 25 L/min. The discrepancy between thermodilution flow and measured flow increased as rate of fluid flow increased.     

Free-running rhythms of adrenocorticotropic hormone (ACTH), cortisol and melatonin in pigs.

In the domestic pig, a circadian rhythm of plasma cortisol occurs, with greatest concentrations in the morning and lowest concentrations in the afternoon. However, photic entrainment of the rhythms of ACTH and melatonin in pigs have not been defined clearly. This experiment was designed to evaluate free-running rhythms of ACTH, cortisol and melatonin in pigs housed in constant light (LL) and constant darkness (DD). Twelve crossbred barrows, maintained under ambient photoperiod, were catheterized and tethered individually in two environmentally controlled rooms, one with LL and the other with DD. For animals in LL, fluorescent lights provided 202 +/- 15 (mean +/- standard deviation) lux of light at 65 cm above the floors. Incandescent nightlights equipped with 7 watt red bulbs provided 7 +/- 2 lux and were illuminated continuously in both rooms. Pigs were given at least 14 d exposure to LL and DD, then samples of plasma and serum were obtained at hourly intervals for 48 hr. Plasma was assayed for ACTH, and serum for cortisol and melatonin. Periodograms were constructed to analyze the data. For this type of analysis, a statistic, Qp, is calculated, and circadian periodicity is suggested if maximum Qp (Qp max) occurs at or near 24 hr. The period of the free-running rhythms (tau) at Qp max for ACTH, cortisol and melatonin for pigs in LL (23.80 +/- .01, 23.78 +/- .01, and 23.21 +/- .02 hr, respectively) did not differ significantly from those for pigs in DD (23.39 +/- .01, 23.20 +/- .01, and 22.55 +/- .02 hr, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

Detection and characterization of leptospiral antigens using a biotin/avidin double-antibody sandwich enzyme-linked immunosorbent assay and immunoblot.

A biotin/avidin double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) for the detection of antigens of Leptospira interrogans serovars in experimentally inoculated bovine urine samples was evaluated. Immunoglobulin G (IgG) from rabbits immunized with L. interrogans serovar hardjo type hardjobovis sonicated, whole cell, and formalinized-heated antigen preparations were purified by a protein A-superose column coupled to fast protein liquid chromatography, and evaluated for species specificity in the ELISA. The ELISA using each specific IgG detected as few as 10(4) leptospires of the homologous serovar hardjo diluted in phosphate-buffered saline solution with Tween 20 (PBSS-Tween 20). On immunoblot analysis of proteinase-K-digested whole cell leptospiral preparations, each IgG revealed the presence of bands specific to serovar hardjo, suggesting the presence of serovar-specific epitopes on the lipopolysaccharide molecules. The minimum number of cells of heterologous serovars pomona, grippotyphosa, bratislava, icterohaemorrhagiae and copenhageni detected by each ELISA was greater, ranging from 10(6) to 10(7). The common antigenic determinants observed on immunoblot analysis were different for each specific IgG, except for a major cross-reacting, possibly flagellar, protein doublet at approximately 36-36.5 kDa. Leptospires were equally well detected by the ELISA in both bovine urine and PBSS-Tween 20.     

Double-blind evaluation of implants of gold wire at acupuncture points in the dog as a treatment for osteoarthritis induced by hip dysplasia.

Thirty-eight dogs with hip dysplasia were studied to evaluate the use of gold wire implants at acupuncture points around the hip joints. They were assigned at random into two groups of 19. In the treated group, gold wire was inserted through hypodermic needles at electrically found acupuncture points around both hips. In the control group, the areas were prepared in the same way but had only the skin pierced at sites which were not acupuncture points, with a needle of the same size as that used in the treated group. Over a period of six months the dogs were studied repeatedly by two veterinarians and by the dogs' owners who were unaware of the treatments the dogs had received; they assessed the dogs' locomotion, hip function and signs of pain. Radiographs were taken at the beginning and end of the study. Although the data collected from both groups by the veterinarians and the owners showed a significant improvement of locomotion and reduction in signs of pain (P=0.036 for the veterinary evaluation and locomotion and P=0.0001 and P=0.0034 for the owners' evaluation of locomotion and pain, respectively), there were no statistically significant differences between the treated and control groups (P=0.19 and P=0.41, P=0.24, respectively).