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Biomedical subjects

B L Hart

Publications and source records attributed to B L Hart.

At least 19 recordsLinked to original sources

Comparison of diazepam with progestin for effectiveness in suppression of urine spraying behavior in cats.

The most common treatment for urine spraying and marking in cats has been administration of long-acting progestins. Treatment with diazepam has recently been gaining favor, particularly because of reported adverse effects of progestins. Results of a clinical trial involving 20 cats indicated that diazepam was effective in eliminating or markedly reducing spraying in 11 (55%) of them. However, most cats required continuous treatment, or at least intermittent treatment, when spraying recurred. The physiologic and behavioral dependency of cats on diazepam, which presumably develops over the course of administration, may contribute to the tendency for spraying to recur once diazepam treatment is discontinued. Using data from previously published findings on progestin administration, plus additional cases, it was documented that a significantly (P less than 0.05) higher percentage of males than females responded favorably. Although the number of cases was not sufficient for a statistical comparison of diazepam vs progestin treatment with regard to male vs female, possible gender difference in the effectiveness of diazepam was not indicated.

Animals

Calcification of the trochlear apparatus of the orbit: CT appearance and association with diabetes and age.

OBJECTIVE: Calcification can sometimes be observed on CT scans in the region of the trochlear apparatus of the orbit, the cartilaginous structure through which the superior oblique tendon and its sheath pass. We evaluated associations of trochlear calcifications with age and diabetes. MATERIALS AND METHODS: We retrospectively reviewed CT scans of the orbit in 159 patients to identify the presence of trochlear calcifications. The presence or absence of diabetes, duration of diabetes, type of therapy, and presence or absence of neuropathy were determined from medical charts of 139 patients. We calculated the odds ratio of detecting a trochlear calcification and used logistic regression to evaluate the associations of age, sex, and diabetes with trochlear calcification. RESULTS: Trochlear calcifications were present in seven of the 24 diabetic patients and in 10 of the 115 nondiabetic patients. The odds ratio for detecting trochlear calcifications in diabetic vs nondiabetic patients was 4.3 (p < .01). Logistic regression showed univariate associations with trochlear calcification for both increasing age (p < .001) and diabetes mellitus (p < .01). The effect of diabetes on the prevalence of trochlear calcifications was seen predominantly in those less than 40 years old (odds ratio = 24.0, p = .014). Sex, duration of diabetes, insulin dependence, and neuropathy were not significantly associated with an increase in trochlear calcifications. CONCLUSION: The results show that a trochlear calcification seen on CT is a benign condition that may serve as a marker for diabetes in young patients. Trochlear calcifications are observed frequently (25-30%) in persons more than 50 years old. When it is present in patients younger than 40 years, it is strongly associated with diabetes.

Adolescent

Behavioral adaptations to parasites: an ethological approach.

Wild vertebrate animals must live in an environment with the ever present threat of internal and external parasites. This threat by macroparasites is responsible for the natural selection of an array of behavioral adaptations that, together with the immune system and other physiological forms of resistance, enable the animals to survive and reproduce in this environment. Several lines of research, some quite recent, illustrate that specific behavioral patterns can be effective in helping animals or their offspring avoid or control macroparasites that can affect adversely the animal's fitness. These behavioral patterns fall under the general strategies of avoidance behavior and mate selection.

Animals

The behavior of sick animals.

Dogs and cats that are ill with febrile diseases usually are depressed and anorexic. When viewed from the standpoint of the wild ancestors, it is apparent that the behavior of sick animals is adaptive and not necessarily a reflection of debilitation. A wild animal that is acutely ill with an infectious disease often is at a life-or-death juncture, and its behavioral mode may be seen as putting the animal's resources into facilitating the fever response in combating the pathogens.

Animals

Cervical stenosis, spondylosis, and herniated disc disease.

While IntCECT is still considered by many to be the optimal modality in cervical spine imaging, it is the most invasive of the techniques considered here. MR imaging may have nearly equivalent diagnostic capability in many cases of degenerative disc and spine disease. The value of unenhanced CT essentially is limited to the demonstration of bony changes. In the evaluation of radiculopathy, either MR imaging or IvCECT is useful for the initial screening and may be the only study needed. MR imaging is the study of choice for diseases of the spinal cord. With continuing progress in MR capability, IntCECT is shifting more toward a supplemental or confirmatory role. A rigid neurodiagnostic algorithm for this common radiologic problem is not possible. Rather, each step of the diagnostic process is influenced by the individual patient. Specific patient characteristics may affect the selection of an imaging modality. Modification of routine studies, such as use of gadolinium or oblique MR imaging, may be indicated in some patients. Finally, because of the high prevalence of asymptomatic disc and spine changes, knowledge of clinical findings is essential in the accurate interpretation of anatomic findings.

Cervical Vertebrae

Antibacterial properties of saliva: role in maternal periparturient grooming and in licking wounds.

Canine saliva was tested for its bactericidal effects against pathogens relevant to the presumed hygienic functions of maternal grooming of the mammary and anogenital areas and licking of wounds. Both female and male saliva were bactericidal against Escherichia coli and Streptococcus canis but only slightly, and nonsignificantly, bactericidal against coagulase positive staphylococcus and Pseudomonas aeruginosa. E. coli is the cause of highly fatal coliform enteritis of neonatal mammals and E. coli and S. canis are the main pathogens implicated in neonatal septicemia of dogs. The bactericidal effects of saliva would facilitate the hygienic function of maternal licking of the mammary and anogenital areas in protecting newborns from these diseases. E. coli and S. canis along with coagulase positive staphylococcus and P. aeruginosa are among the common wound contaminants of dogs. Wound licking, and the application of saliva, would thus reduce wound contamination by E. coli and S. canis. The resistance of staphylococcus to bactericidal effects of saliva may be a factor in the high frequency (46 percent) with which coagulase positive staphylococcus was isolated from wounds compared with much lower frequency (9-17 percent) with which E. coli and S. canis were isolated.

Animals

Behavioral adaptations to pathogens and parasites: five strategies.

The ever present threat of viral, bacterial, protozoan and metazoan parasites in the environment of wild animals is viewed as responsible for the natural selection of a variety of behavioral patterns that enable animals to survive and reproduce in this type of environment. Several lines of research, some quite recent, point to five behavioral strategies that vertebrates utilize to increase their personal or inclusive fitness in the face of parasites (broadly defined to include pathogens). These are: 1) avoidance of parasites; 2) controlled exposure to parasites to potentiate the immune system; 3) behavior of sick animals including anorexia and depression to overcome systemic febrile infections; 4) helping sick animals; 5) sexual selection for mating partners with the genetic endowment for resistance to parasites. The point is made that to consider a behavioral pattern as having evolved to serve a parasite control function the parasite or causative agent should be shown to adversely impact the animal's fitness and the behavior in question must be shown to help animals, or their offspring or group mates, in combating their exposure, or reducing their vulnerability, to the parasite.

Adaptation, Psychological

Age and race related changes in mammographic parenchymal patterns.

The relationship between breast parenchymal patterns and age was examined in a nonselected, nonreferred group. The three major racial-ethnic subgroups represented have markedly different incidences of breast cancer, with Anglos (nonHispanic caucasians), Hispanics, and American Indians having higher to lower incidence rates of breast cancer, respectively. Mammograms were performed in 519 victims of nonhospital, nonnatural or unexplained deaths in New Mexico. The percentage of dense breast patterns (DY + P2) decreased with age for all groups. American Indian women showed a much earlier shift to a lower density parenchymal pattern than Anglo or Hispanic women. At older ages Indian women continued to have a slightly lower percentage of dense breast patterns than the other groups. The changes in breast parenchymal pattern with age and ethnic groups may reflect factors related to risk of breast cancer.

Adolescent

Radon: is it a problem?

Radon gas is a major source of radiation exposure to the general public. Radon-222 is a product of uranium-238, present in varying concentrations in all soils. Radon enters buildings from soil, water, natural gas, and building materials. Its short-lived breakdown products, termed "radon daughters," include alpha-emitting solids that can deposit in the lungs. Firm evidence links lung cancer risk in miners with high exposure to radon daughters. The amount of risk associated with the much lower but chronic doses received in buildings is difficult to establish. By some extrapolations, radon daughters may be responsible for a significant number of lung cancer deaths. The existence or extent of synergism with smoking is unresolved. Local conditions can cause high levels of radon in some buildings, and measures that reduce indoor radon are of potential value.

Bismuth

Pulmonary needle embolism from intravenous drug abuse.

Although the embolization of catheters and other foreign bodies in blood vessels is a well-known happening, needle embolization has rarely been reported. We describe here an instance in which a hypodermic needle broke in a man's skin during cocaine injection. The needle fragment was observed to migrate within a short time to the periphery of the left lung. The patient did not develop complications. The limited literature available indicates that such peripheral embolization usually follows a benign course.

Adult

Alteration in vomeronasal system anatomy in alcelaphine antelopes: correlation with alteration in chemosensory investigation.

Ruminants typically have an incisive papilla and incisive ducts located on the hard palate just behind the dental pad which are involved in transferring fluid-borne stimulus material from the oral cavity to the vomeronasal organs (VNOs) during flehmen. This behavior in males is presumably involved in the detection of chemosensory cues in female urine which indicate sexual status. Two species of alcelaphine antelopes, topi and Coke's hartebeest, were found to lack the incisive papilla and incisive ducts constituting the oral connection to the VNOs. This distinctive anatomical feature is complemented in these species not only by lack of flehmen behavior, but also a de-emphasis on chemosensory interest in female urine during sexual encounters. The common wildebeest, which is also an alcelaphine antelope, lacks the incisive papilla, but has small incisive ducts. Wildebeest males do perform flehmen to urine from females. However, during flehmen in the wildebeest, intermittent nostril licking apparently delivers the stimulus material to the VNOs via the nasal route, possibly compensating for reduced oral access to the VNOs. These observations on alcelaphine antelopes would appear to represent a unique feature among the world's ruminants.

Animals

Biological basis of the behavior of sick animals.

The most commonly recognized behavioral patterns of animals and people at the onset of febrile infectious diseases are lethargy, depression, anorexia, and reduction in grooming. Findings from recent lines of research are reviewed to formulate the perspective that the behavior of sick animals and people is not a maladaptive response or the effect of debilitation, but rather an organized, evolved behavioral strategy to facilitate the role of fever in combating viral and bacterial infections. The sick individual is viewed as being at a life or death juncture and its behavior is an all-out effort to overcome the disease.

Animal Diseases