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Biomedical subjects

B L Hart

Publications and source records attributed to B L Hart.

At least 91 records · Page 5Linked to original sources
PubMed1986

Pain-only decompression sickness affecting the orbicularis oculi.

A case is reported of a diver who experienced the onset of pain in the left orbicularis oculi muscle approximately 20 min after surfacing from an experimental dive. A careful neurologic examination disclosed no abnormality. The response of the orbicularis oculi muscle to stimulation of the facial nerve and the blink reflex were both normal as recorded with a clinical neurophysiologic recording system (Nicolet CA 1000). The pain resolved quickly with recompression, supporting a diagnosis of pain-only decompression sickness in this small facial muscle.

Adult↗
PubMed1986

Compression pain in a diver with intraosseous pneumatocysts.

A 30-yr-old diver experienced pain in the area of the sacroiliac joint during the descent phase of air diving to less than 10 ATA. Computed tomography of the pelvis demonstrated two gas-filled cysts within the ilium. The mechanism by which this lesion causes pain is discussed and reports of gas within bone are reviewed.

Adult↗
PubMed1985

Behavioral indications for phenothiazine and benzodiazepine tranquilizers in dogs.

In a controlled study on 18 caged dogs, the effects of 2 psychoactive drugs on friendliness, excitability, and fearfulness were systematically and quantitatively evaluated. Diazepam was selected to represent the benzodiazepine group, and chlorpromazine represented the phenothiazine group. Diazepam was more effective in suppressing signs of fear than was chlorpromazine. Diazepam increased measures of excitability, whereas chlorpromazine had opposite effects.

Amitriptyline↗
PubMed1985

Behavioral profiles of dog breeds.

Breed behavior profiles were obtained by a method that was quantitative and free of personal biases. The profiles concerned 13 traits, eg, excitability, snapping at children, watchdog barking, and affection demand, which are of interest to people wanting dogs as pets. Authorities for the development of the profiles were 48 small animal veterinarians and 48 obedience judges, randomly selected from directories so as to represent equally men and women, and eastern, central, and western geographic regions of the United States. Each authority was asked to rank on each of the behavioral traits a list of 7 breeds chosen randomly from a list of 56 breeds. The data were analyzed in a custom-designed computer program that pooled the data and then ranked all 56 breeds on the basis of the 13 traits. The results indicated that some behavioral traits discriminate between breeds better than others. An examination of sample profiles indicated the feasibility of developing a statistically meaningful behavioral profile that integrates comparative rankings of several authorities balanced as to representation of geographic location, sex, and type of experience with dogs.

Analysis of Variance↗
PubMed1985

Selecting pet dogs on the basis of cluster analysis of breed behavior profiles and gender.

Using a computer-generated data base of rankings of 56 breeds of dogs on 13 behavioral traits, a factor analysis was performed to determine the extent to which a few general underlying behavioral tendencies are manifested in specific characteristics. Three factors, referred to as reactivity, aggression, and trainability, accounted for 81% of the variance in the 13 behavioral traits. Subsequently, a cluster analysis was performed to generate 7 clusters of dog breeds on the basis of similarity in scores for each of the 3 main factors. The clusters reflected to some degree the conventional groupings of dogs into working, sporting, hound, and terrier breeds. A quantitative analysis of the ranking of male dogs vs female dogs for the 13 characteristics revealed that males differed from females on 10 traits. It was concluded that these gender and cluster profiles will allow people to select a breed or gender of dog that is most likely to match the emotional and physical needs of the person who will provide a home for the pet.

Animals↗
PubMed1985

Effect of prepubertal versus postpubertal castration on sexual and aggressive behavior in male horses.

Males horses castrated prepubertally occasionally display stallion-like sexual and aggressive behavior as adults. A retrospective survey of 140 horse owners was undertaken to compare the effectiveness of prepubertal versus postpubertal castration on objectionable sexual and aggressive behavior. Of 94 geldings that had been castrated prepubertally (before 2 years of age), 20% to 30% displayed stallion-like sexual behavior and aggression toward horses, and 5% were aggressive toward people in a stallion-like manner. This occurrence of problem behavior was not significantly different from the occurrence of these behavioral patterns in 46 geldings that had been castrated as stallions (over 3 years of age). When castration was examined as a therapeutic measure to eliminate sexual and aggressive behavior in stallions in which the behavior had become objectionable, it was found that the operation was effective on sexual behavior and aggression toward people in 60% to 70% of horses and on aggression toward horses in 40% of horses.

Aggression↗
PubMed1985

Vomeronasal organ cannulation in male goats: evidence for transport of fluid from oral cavity to vomeronasal organ during flehmen.

A chronic cannulation procedure is described which allows for sampling vomeronasal organ (VNO) contents repeatedly in freely moving conscious subjects. In 5 male goats an indwelling cannula was used to test the hypothesis that flehmen facilitates the transport of fluid from the oral cavity to the VNO. Flehmen was evoked by placing urine mixed with a tracer dye, sodium fluorescein, in the oral cavity. Water labeled with the same concentration of fluorescein dye was used as a control substance to test for transport during non-flehmen. The VNO contents were sampled during flehmen as well as after non-flehmen and the concentration of dye analyzed by means of a spectrofluorophotometer. The concentration of dye found in the VNO was markedly higher after the occurrence of flehmen than non-flehmen.

Animals↗
PubMed1985

Analysis of the catnip reaction: mediation by olfactory system, not vomeronasal organ.

Pet owners and behavioral scientists alike are fascinated by unique behavioral reactions that cats show in the presence of catnip. These experiments explored the possibility that the catnip reaction might be triggered by chemosensory stimulation of the vomeronasal organ. In the chewing and mouthing of the catnip source, substances might be dissolved in saliva and transported to the vomeronasal organ. The rolling and rubbing during a catnip reaction might be a sexual response activated by the accessory olfactory system since the system projects to parts of the brain involved in mediation of sexual behavior. However, removal of the vomeronasal organ did not attenuate any of the behavioral reactions to catnip. Olfactory bulbectomy immediately eliminated catnip responding, revealing that the chemosensory stimulus evoking the catnip reaction is undoubtedly mediated through the main olfactory system. Catnip activates behavioral elements associated with several species-specific behaviors, including sniffing and chewing as associated with oral appetitive behavior, rolling and rubbing characteristic of female sexual behavior, batting the catnip source characteristic of play behavior, and a type of kicking associated with predatory behavior. These behavioral reactions occur randomly and intermittently.

Animals↗
PubMed1985

Female and male sexual responses in female cats with ventromedial hypothalamic lesions.

The effects of lesions in the ventromedial hypothalamus (VMH) on male and female sexual behavior in female cats were examined. Following preoperative testing for receptivity, proceptivity, and male mating behavior, 27 female cats received either lesions in the anterior or posterior portion of the VMH or sham lesions. Neither of the VMH lesion placements reduced proceptivity and receptivity scores. However, the female mating pattern was significantly altered in that although females in both lesion groups initially allowed a stud male to mount, they usually did not allow the male to intromit. As in rodents, the VMH in the cat appears to be an important neural area for the display of normal female sexual behavior. Low levels of male sexual behavior were seen in the three groups preoperatively, and no changes were observed in the levels of male behavior following lesion placement. Thus, because lesions that disrupted female behavior did not affect male sexual behavior, it appears that the neural areas controlling homotypical and heterotypical sexual behaviors are not necessarily neurally linked.

Animals↗
PubMed1984

Factors relating to urine spraying and fighting in prepubertally gonadectomized cats.

The fact that male cats are routinely castrated prior to full sexual maturity for behavioral reasons prompted a survey of the prevalence of these behaviors in prepubertally gonadectomized male and female cats. About 10% of the 134 male and 5% of the 152 female cats studied engaged in spraying on a frequent basis later in adult life. Problem spraying and fighting in males was of the same order of magnitude as in males castrated in adulthood after the problem behaviors had appeared. The age of prepubertal castration, ranging from 6 to 10 months, had no influence on spraying or fighting later in life. It was found that male cats are more likely to spray and fight if they are in households with female cats than with other male cats. With regard to female cats, spraying or fighting was less than that of male cats. Age at the time of gonadectomy was not a factor in their tendency to spray or fight. Possible prenatal masculinization of female fetuses by male fetuses, as revealed by littermate composition, was not a factor in the predisposition of female cats to spray or fight.

Aggression↗
PubMed1983

Differences in responsiveness to testosterone of penile reflexes and copulatory behavior of male rats.

The display of penile reflexes and copulatory behavior appears to reflect the activity of two different underlying neuronal system, both of which are modulated by systemic testosterone (T) concentration. To indirectly compare the two systems, the responsiveness to T of penile reflexes and copulatory behavior was examined. In the first experiment castrated spinal male rats were given penile reflex tests while receiving replacement T through Silastic capsule implants filled with T (50 mm T). After capsule removal the number of penile erections and flips declined within 24 hr and gradually decreased for 12 days. Subjects were then reimplanted with new 50-mm T capsules. The number of penile flips and erections increased within 6 and 12 hr. respectively. This is a much more rapid response rate to T than has been established for copulatory behavior. In the second experiment castrated spinal male rats were tested for penile reflexes with a 50-mm T capsule, which was then replaced with a 10-, 5-, or 2-mm T or an empty capsule. The number of penile reflexes declined in a dose-response fashion. In the third experiment, castrated sexually experienced male rats were tested for copulatory behavior with two 25-mm T capsules which were then replaced with a 10 or 2-mm T or an empty capsule. Only males with empty capsules had decrements in copulatory behavior, revealing that a low level of T can maintain virtually normal sexual behavior despite a marked decline in penile reflex activity. The neuronal system underlying penile reflexes (spinal neurons) is apparently much more responsive to changes in T concentrations than the neuronal system underlying motivational and appetitive aspects of copulatory behavior (brain neurons).

Animals↗
PubMed1983

Penile mechanisms and the role of the striated penile muscles in penile reflexes.

Gross and subgross anatomical observations of the penis pointed to a mechanical arrangement whereby contraction of the bulbocavernosus (BC) muscles would enhance erections of the glans penis and contraction of the ischiocavernosus (IC) muscles would enhance or produce penis flips. These functions for the muscles were confirmed by electromyographic recordings taken during tests of penile erections and flips in spinal male rats. Surgical removal of the BC muscles did not reduce the total number of erections during penile reflex tests, but did eliminate the flared-cut type of erections. Surgical removal of the IC muscles reduced the occurrence of penile flips and virtually eliminated the long or extended flips. It is hypothesized that contractions of the BC and IC muscles, in producing penile cups and long flips, play a role in dislodgement of previously deposited seminal plugs and deposition of new plugs during mating. Contraction of the BC muscles, in forcefully emptying contents of the urethral diverticulum, would appear to play a role in the ejaculatory process by which the sperm-dense fraction of semen is first delivered to the vagina followed by delivery of a rapidly coagulating seminal plug.

Animals↗
PubMed1983

The role of the striated penile muscles of the male rat in seminal plug dislodgement and deposition.

Seminal plugs, which must be tightly adhered to the vaginal walls for optimal fertilization, are disturbed or loosened by copulatory intromissions. In multi-male mating encounters, a male may reduce the sperm delivered by a previous male by dislodging the former male's plug and depositing his own sperm and plug. Recent work has documented that the striated penile muscles are involved in the production of penile erectile cups and flips. This study focused on the effects of penile muscle excision on the ability of male rats to dislodge and deposit tight plugs. Using a radiopaque contrast medium to visualize if a seminal plug was tightly adhered to the vaginal wall, displaced caudally or dislodged, Experiment 1 examined the manner in which plugs were removed during a series of intromissions. The dislodgement process was envisioned as a gradual one beginning with caudal displacement which occurs during the first or second intromission. Following excision of either the bulbocavernosus (BCX) or ischiocavernosus (ICX) muscles in Experiment 2, plug disturbance ability was impaired in 54 percent and 40 percent of BCX and ICX subjects respectively. Ability to deposit tight plugs was impaired in 45 and 20 percent of BCX and ICX subjects respectively.

Animals↗
PubMed1983

Role of testosterone secretion and penile reflexes in sexual behavior and sperm competition in male rats: a theoretical contribution.

A number of experiments have documented that when male rats are exposed to female rats they undergo a marked increase in the secretion of luteinizing hormone and testosterone. This response can be conditioned to other, previously neutral, stimuli associated with mating. Recent work has highlighted the remarkable sensitivity of penile reflexes to fluctuations in blood concentration of testosterone. Other work has pointed to the function of penile reflexes in seminal plug removal and deposition. It is hypothesized that penile reflexes are potentiated by the increase in testosterone that occurs in response to sexually relevant cues and that the potentiated reflexes play a role in sperm competition during multi-male mating encounters. The sperm competition centers around a male rat's ability to dislodge seminal plugs left in the vagina by other males and to deposit his own plug as tightly as possible to resist dislodgement by another.

Animals↗
PubMed1983

Female sexual responses in male cats facilitated by olfactory bulbectomy and medial preoptic/anterior hypothalamic lesions.

Bilateral lesions of the medial preoptic/anterior hypothalamic area and olfactory bulbectomies were performed sequentially in sexually active male cats, with the order of operations balanced. Male sexual behavior was virtually eliminated by the combined operations in all cats. Increased levels of female proceptive behavior were seen following either type of lesion alone, and combined operations resulted in increased levels of receptivity. The results support the concept that there exists, within the brains of male animals, the neural basis for the display of female as well as male sexual responses and that certain brain operations may potentiate the display of female responses. However, it does not appear that the reduction of male behavior is necessarily coupled with an increase in female behavior since no correlation was seen between the degree of enhancement of female behavior and the decrement in male behavior.

Animals↗
PubMed1982

A technique for cutting slices from femoral heads and other awkwardly shaped bones.

For cutting thin, parallel slices from round and other awkwardly shaped bones, we have developed an useful aid by modifying the Microslice II cutting saw primarily designed for geological or metallurgical purposes. To ensure a good grip of the bone, the specimen is embedded in a bolus of wax in a cylindrical container and is advanced along the container by a screw plunger toward the cutting blade of the machine. It is thus possible to cut even from awkwardly shaped bones 2-30 mm thick parallel slices suitable for decalcified or undecalcified histological sections and also for radiodensitometry or quantitative microradiography.

Bone and Bones↗