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Biomedical subjects

B W Bennett

Publications and source records attributed to B W Bennett.

11 recordsLinked to original sources
PubMed1993

Effects of shipping, handling, adrenocorticotropic hormone, and epinephrine on alpha-tocopherol content of bovine blood.

In 2 studies, plasma, erythrocyte, and neutrophil alpha-tocopherol concentrations were monitored in beef cattle after shipping, handling, and sample collection. On the basis of alpha-tocopherol results, an additional 2 studies were designed to measure the effects of administration of adrenocorticotropic hormone (ACTH) and epinephrine on the alpha-tocopherol concentration in the aforementioned blood constituents and on creatine kinase (CK) activity in Holstein calves. In the first of these studies, 15 beef cattle that had recently arrived at the feedlot consumed feed supplemented daily with 1,000 IU of dl-alpha-tocopheryl acetate. Values for initial blood samples indicated that CK activity was high. Although plasma alpha-tocopherol concentration indicated that vitamin supplementation was adequate, RBC and neutrophil alpha-tocopherol values were generally nondetectable. After 4 weeks of supplementation, plasma alpha-tocopherol concentration increased (P < 0.05), and neutrophil and RBC alpha-tocopherol values became measurable in most of the cattle. In the second study, 6 beef heifers had decreased (P < 0.05) plasma, RBC, and neutrophil alpha-tocopherol values after multiple periods of handling and blood sample collection. In the third and fourth studies, 10 tamed Holstein heifer calves, 5 of which were administered ACTH and epinephrine to simulate stress effects on blood alpha-tocopherol concentrations and CK activity. In study 3, the vitamin E-adequate heifers had increased blood CK (P < 0.001) activity and cortisol (P < 0.01) concentration, and decreased (P < 0.05) neutrophil alpha-tocopherol concentration after hormone injections.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗
PubMed1988

Association of bovine respiratory syncytial virus with atypical interstitial pneumonia in feedlot cattle.

Thirty-three cattle with fatal respiratory tract disease were examined for gross and histologic lesions and for the presence of viral and bacterial agents in the lungs. Fifteen cattle had lesions characteristic of atypical interstitial pneumonia (AIP), and 18 had other respiratory tract diseases, including infectious bovine rhinotracheitis, shipping fever pneumonia, bronchopneumonia, pulmonary abscess, and edema of the trachea. Gross necropsy findings in the cattle with AIP were uncollapsed and emphysematous lungs; histopathologic findings included interstitial edema, thickening of alveolar walls, hyaline membrane formation, and hyperplasia of type-II pneumonocytes. The infective agents found in the lungs of the 33 cattle included bovine respiratory syncytial virus, bovine herpesvirus type 1, Pasteurella sp, mycoplasmas, and Corynebacterium pyogenes. Bovine respiratory syncytial virus was detected by use of immunofluorescence and immunoperoxidase on lung tissue sections; bovine herpesvirus type 1 was detected by these techniques and by isolation of the virus. Bovine respiratory syncytial virus was significantly (P = 0.01) associated with lesions of AIP (11 of 15), compared with those of other respiratory tract diseases (5 of 18).

Animals↗
PubMed1986

Muscle lipoprotein lipase activity in voluntarily exercising rats.

Voluntary exercise of rats in freely rotating work wheels has been extensively used, but muscle adaptations that result from such exercise training are poorly documented. The purpose of this study was to determine whether the exercise performed by voluntarily active rats would increase succinate dehydrogenase or lipoprotein lipase activities in the soleus muscle (SM) or the red portion of the vastus lateralis muscle (RV). In SM the activities of these two enzymes were not increased after 7 or 16 wk of voluntary exercise. Succinate dehydrogenase activity in RV was moderately increased after 7 and 16 wk of voluntary activity (P less than 0.05). Substantial increases occurred in RV lipoprotein lipase activity (P less than 0.01). The increase in RV lipoprotein lipase activity was positively related to distance run by the rats. The results indicate that only small muscle-dependent increases in mitochondrial enzymes occur in rats allowed to exercise voluntarily in rodent work wheels. Voluntary exercise training induced a selective increase in lipoprotein lipase activity in a muscle containing a high percentage of fast-twitch red fibers, a response absent in a muscle containing a predominance of slow-twitch red fibers. It is unlikely that this differential response can be explained by exercise-induced changes in plasma hormone concentrations involved in the regulation of lipoprotein lipase.

Animals↗
PubMed1986

Eosinophilic myositis and muscular sarcocystosis in the carcasses of slaughtered cattle and lambs.

Fifty-three bovine and 7 ovine carcasses condemned for having eosinophilic myositis were evaluated. Four (7.3%) of the bovine carcasses had a few, large local lesions in skeletal muscles (category A), and 49 (92.7%) of the bovine carcasses and 7 (100%) of the ovine carcasses had multiple, small, disseminated lesions in tongue, esophagus, heart, diaphragm, or skeletal muscles (category B). Tissue from carcasses of category B were evaluated for bacteria, viruses, selenium, and pathologic changes. Pathogenic bacteria and viruses were not isolated and selenium concentrations were normal. In category B, all carcasses had granulomas; of the 49 bovine carcasses and 7 ovine carcasses, 38 (77.6%) and 7 (100%), respectively, had one or more granulomas with opened dead sarcocysts. The data indicated that opened sarcocysts killed the host myocyte and adjacent myocytes and stroma, thereby initiating granuloma formation.

Animals↗
PubMed1986

Airborne particle concentration and meteorologic conditions associated with pneumonia incidence in feedlot cattle.

To elucidate the role of air quality on the occurrence of pneumonia in feedlot cattle, the following environmental values were measured at a feedlot: suspended particulates in 5 particle-size fractions, relative humidity, air temperature, and barometric pressure. Pneumonia incidence data were classified by the number of days the cattle had been at the feedlot (days on feed). The concentration of airborne particles, range of temperature, days on feed, and season of the year were associated with incidence of pneumonia in cattle. Pneumonia incidence rates were greatest both within 15 days of arrival at the feedlot and during the fall sampling periods. The incidence of pneumonia in the 16 to 30 days-on-feed group was closely associated with the concentration of particles 2.0 to 3.3 microns in diameter and the range of daily temperature when exposure occurred 15 days before the onset of disease in the fall and 10 days before in the spring.

Air Pollutants↗
PubMed1984

Slaughter weight loss attributable to pregnancy in feedlot heifers.

Slaughter weight loss attributable to pregnancy in feedlot heifers was determined by immediate postmortem weighing of uteri and uterine contents of pregnant heifers. For each 10% pregnant animals within a group of slaughter heifers, the dressing percentage was reduced for the entire group by 0.66%.

Animals↗
PubMed1983

How many miles to the doctor?

We used detailed information from 16 states to determine the distance that residents of outlying areas (or of towns of less than 25,000, outside metropolitan areas) must travel to receive various types of medical care. For both 1970 and 1979, we found that approximately 80 per cent of such residents lived within 10 miles' driving distance of some physician and 98 per cent lived within 25 miles. Most of the remaining 2 per cent lived in areas so sparsely settled that physicians will not find them economically attractive as practice locations. During the 1970s, the distance of members of the studied population from medical and surgical specialists was substantially reduced. The greatest improvement occurred for the specialties that had the largest percentage increase in their numbers. As the physician pool expands further during the 1980s, geographic access to specialty care for rural and small-town residents should show a further notable improvement. However, this improvement may not suffice to meet what some consider the "medical need" of those who are geographically isolated or economically deprived.

Health Services Accessibility↗
PubMed1983

Bovine genital campylobacteriosis (vibriosis): vaccination of experimentally infected bulls.

The therapeutic efficacy of a Campylobacter fetus subsp venerealis bacterin was determined in experimentally infected bulls. Ten of twelve 5-year-old Angus bulls became infected after being infused intrapreputially with C fetus subsp venerealis. Of the 10 bulls, 6 were vaccinated with 5 ml of C fetus subsp venerealis vaccine on 2 occasions 4 weeks apart. Preputial washings of the vaccinated bulls were culturally negative by the 8th week after primary vaccination. None of the 18 heifers exposed to the vaccinated bulls became infected. The 4 infected, nonvaccinated bulls remained culturally positive to C fetus (P less than 0.002), and each bull infected at least 1 heifer (P less than 0.001). Two noninfected, nonvaccinated bulls remained culturally negative and did not infect any heifer. The 4 infected, nonvaccinated bulls were then vaccinated. Two bulls remained infected 9 weeks after primary vaccination, as determined by the virgin heifer test and cultural examination of preputial washings. Serologic data from 7 sampling periods were different (P less than 0.001) for vaccinated vs nonvaccinated bulls at 4 (against K antigen) or 6 (against O antigen) weeks after primary vaccination. Vaccination was effective in eliminating the infection in most of the infected bulls, but cannot be recommended as the sole measure of control in infected herds.

Animals↗
PubMed1982

Where have all the doctors gone?

As the supply of physicians grew during the 1970s, medical and surgical specialists diffused into smaller communities. In 1979, nearly every town with a population of more than 2,500 had ready access to a physician. The overall pattern of physician distribution was quite similar in the four disparate geographic regions chosen for study. The data strongly suggest that competitive forces play a major role in determining where physicians choose to practice. As the pool of physicians expands during the 1980s, a wide range of services will become increasingly available to populations outside metropolitan areas. The methods developed here provide important tool for evaluating and shaping health manpower policy.

Career Choice↗
PubMed1980

The changing geographic distribution of board-certified physicians.

We studied the recent distribution of board-certified specialists among cities and towns of different sizes. Between 1960 and 1977, diplomates of the eight specialty boards that we studied appeared for the first time in many small nonmetropolitan towns. The percentage increase in numbers of specialists in small towns significantly exceeded that in cities, but the absolute increase in specialists per 100,000 persons was greater in metropolitan areas. Our findings suggest that the increased supply of specialists activated market forces that caused the observed changes in distribution. It is also possible that a new preference for small-town living has contributed to this evolving pattern. If an increase in physician supply has been the major force responsible for the movement into nonmetropolitan areas, this trend implies that smaller and smaller towns will acquire board-certified specialists as the number of physicians increases.

Cardiology↗