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Biomedical subjects

J W Bennett

Publications and source records attributed to J W Bennett.

70 records · Page 4Linked to original sources
PubMed1976

Effect of acetone on production of aflatoxins and versicolorin pigments by resting cell cultures of Aspergillus parasiticus.

Resting cell cultures of Aspergillus parasiticus were grown in medium containing four different concentrations of glucose, with and without acetone. In addition, the effect of different equimolar concentrations of acetone, acetic acid, ethanol, and sodium acetate was compared at two glucose levels. Aflatoxin and versicolorin pigment production increased in resting cell medium containing increasing concentrations of glucose. In the presence of glucose high concentrations of acetone (1.0 and 0.25 M) inhibited secondary biosynthesis and low concentrations of acetone (0.1, 0.025 and 0.01 M) stimulated secondary biosynthesis of aflatoxins and versicolorin pigments.

Acetates↗
PubMed1975

Influences of chronic denervation of the carotid bifurcation regions on panting in the sheep.

The respiratory response of conscious sheep subjected to severe heat stress has been assessed before and up to 17 weeks after bilateral denervation of the carotid bifurcations. The characteristic response of the intact animal comprises an initial phase of rapid, shallow panting, superseded by panting of a slower, deeper form which results in a severe respiratory alkalosis; this was not significantly altered by the denervation. However, during recovery from heat stress, denervated animals developed a marked hypoxaemia and tachycardia. Blood pressure was much more labile in denervated animals. After denervation, resting arterial PCO2 was higher, PO2 was lower, and blood pressure and heart rate were higher; with the lapse of weeks, these parameters returned towards pre-denervation levels although the carotid bodies remained inactive. It is concluded that the carotid bodies do not play a significant role in control of the biphasic pattern of panting during severe heat stress, but that they normally prevent post-hyperventilation hypocapnic hypoxaemia during recovery. Further, the respiratory pattern during heat stress is the results of an overwhelming thermoregulatory drive, whereas the pattern during recovery is the result of a balance between arterial and medullary chemoreceptor activity, Finally, the carotid bodies normally play a significant role in determining the 'set-point' for CO2 regulation, but in their absence respiratory control mechanism adapt over a considerable time period.

Animals↗
PubMed1975

Brown adipose tissue in the new-born calf (Bos taurus).

1. Electron microscopic examinations revealed that most of the adipose tissue of new-born calves had the cellular morphology of brown adipose tissue; only subcutaneous tissue had the cellular morphology of white adipose tissue. 2. The cellular morphology of the brown adipose tissue changed progressively to that of white adipose tissue as the age of the calves increased. 3. Infusion of noradrenaline (I.V.) at rates of 1 and 5 mug/kg.min into new-born calves exposed to a thermoneutral environment increased metabolic rate two- to threefold, and also increased rectal temperature and respiration rate. The responses declined as age of calf increased. 4. Approximately 2% of the body weight of new-born calves appears to be brown adipose tissue.

Adipose Tissue↗
PubMedDate not supplied

Dental composite for the fixation of mandibular fractures and luxations in 11 cats and 6 dogs.

Twenty-one mandibular fractures in 11 cats and 6 dogs were repaired during a 20-month period. A new technique using dental composite was used to stabilize the mandible. The canine teeth were pumiced, acid etched, and aligned with dental composite, leaving the mouth opened approximately 1 cm. Six weeks after surgery the composite was removed so that radiographs of the mandible could be made with the animal under general anesthesia. In 1 dog in which the fracture had not healed, the composite was replaced. The composite broke before 6 weeks in 8 animals; 2 required replacement of the dental composite. There were no other complications. The median time for fracture healing was 6 weeks. All fractures healed with anatomic dental occlusion. The advantages of this technique are that no further damage is caused to the teeth or to the blood supply of the bone, the occlusion is anatomic, dermatitis (which is seen with tape muzzles) is not a complication, and the technique is easy to use in brachycephalic breeds, cats, and animals with poor bone quality. The limiting factor of this technique is that it does require four salvageable canine teeth. This repair technique is still a viable option even if one or more of the canine teeth are fractured. Dental composite stabilization is fast, easy, inexpensive, and, in our series, it was 100% effective for the repair of mandibular fractures.

Acid Etching, Dental↗
PubMedDate not supplied

"The branches into which bacteriology is now ramifying" revisited.

The American Society for Microbiology was originally founded in 1899 as the Society of American Bacteriologists. The transition from "bacteriology" to "microbiology" and from an emphasis on the identity of the membership (bacteriologists) to an emphasis on the discipline (microbiology) was a contentious one that occurred in several steps. This article reviews the history and events that accompanied this development.

Bacteriology↗