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Biomedical subjects

J D Robinette

Publications and source records attributed to J D Robinette.

13 recordsLinked to original sources
PubMed1988

Heart rates in the captive, free-ranging beaver.

1. Heart rates of beaver (Castor canadensis) under free-ranging captive conditions for active behaviors and resting in water (approximately 121 beats/min) were significantly (P less than 0.01) higher than for resting on land (100 beats/min). 2. Although no transient recovery tachycardia was evident in swimming heart rates following diving, average swimming heart rates were higher (127 beats/min) after diving than after other precursor behaviors (123 beats/min). 3. Beaver exhibited bradycardia when sleeping (75 beats/min), diving (61 beats/min), and when threatened on land (57 beats/min). 4. The respiratory sinus arrhythmia indicated a respiratory rate of 15 breaths/min. 5. Cold temperatures (approximately 0 degree C) elicited higher heart rates than did warmer temperatures (approximately 20 degrees C) in active, non-diving behaviors (P less than 0.05).

Animals↗
PubMed1988

Inheritance of diabetes mellitus in Keeshond dogs.

The genetic aspects of inherited, insulin-dependent diabetes mellitus of Keeshond dogs were studied retrospectively and in a prospective mating program. The symbol dm was used to designate the gene that causes hypoplasia of the islets of Langerhans. The retrospective study disclosed 4 diabetic dogs; prospective outcross, backcross, and inbred matings disclosed 49 diabetic dogs. Outcrossing demonstrated that the diabetic phenotype was displayed readily against a genetic background of a breed other than the Keeshond. In dogs with the dm/dm genotype, onset of diabetes was most frequent before the dog was 6 months old, but did occur in some older dogs. The dm genotype was best described as autosomal recessive.

Animals↗
PubMed1987

Cecal perforation and adrenocortical adenoma in a dog.

Cecal perforation was diagnosed in a dog with a history of acute vomiting. The dog also had an adrenocortical adenoma. Intestinal perforation can be a serious complication of cortico-steroid treatment in the dog, but has not been attributable to hyperadrenocorticism. Fever and an inflammatory CBC were not observed, which could have been secondary to adrenal-dependent hyperadrenocorticism. The acute abdominal crisis associated with peritonitis required quick resolution in an attempt to save the dog, but also precluded any further diagnostic procedures for possible hyperadrenocorticism. The signs that suggested hyper-adrenocorticism in this dog included alopecia, lymphopenia, eosinopenia, high liver enzyme activities, hypercholesterolemia, and one large and one small adrenal gland. This latter finding presumably indicated negative feedback suppression and atrophy attributable to a functional adrenocortical adenoma.

Adenoma↗
PubMed1985

Aortic bulb-aortic orifice hemodynamics in left ventricle-systemic arterial interaction.

Experiments were conducted in open-chest dogs in which ascending aortic blood flow (Q) was measured with an electromagnetic flow probe, and pressure was measured in the left ventricle (LV) and ascending aorta. The aorta just distal to the flow probe was occluded suddenly, causing the aortic bulb (AB) to be the only part of the arterial system to be in communication with the LV during clamped beats. Pressure and flow data from preocclusion, occlusion, and occlusion-release periods were analyzed to assess AB compliance (CAB) and the longitudinal impedance properties of inertance (LVO) and resistance (RVO) in the AB-aortic orifice region. In five dogs (avg wt 24.2 kg), the mean and range of values were as follows: CAB = 45 (31-55) X 10(-4) cm5/dyn; LVO = 1.86 (0.76-2.88) dyn X s2 X cm-5, RVO = 4.07 (0.66-8.55) dyn X s X cm-5. The volume-accommodating actions of CAB caused actual LV outflow to be characteristically different from Q and aortic-clamped beats to be nonisovolumic. Actions of the AB were found to be important in the estimation of arterial characteristic impedance as a component of LV afterload and in the estimation of the LV pump properties of time-varying elastance and internal resistance.

Animals↗
PubMed1984

Mechanical determinants of transient changes in stroke volume.

To better define beat-to-beat regulation of stroke volume (SV), the several-beat transient response of the left ventricle (LV) to sudden changes in hydraulic loading impedance was studied. Data were collected from eight canine isolated heart-lung preparations with controlled LV loading impedance. At a selected diastolic interval, a sudden increase in hydraulic loading resistance was induced. The resulting transient response in SV, end-diastolic pressure (EDP), and end-systolic pressure (ESP) was analyzed by comparing the relative predictive capability of six competing models, each incorporating different degrees of complexity in the relationship between SV and EDP and ESP. The basic model assumed linear LV pressure-volume relationships at both end diastole and end systole. Incorporation of nonlinear, end-state interaction or coronary perfusion pressure effects into the basic model did not improve predictive performance. Models incorporating SV and ESP of the preceding beat as well as ejecting beat ESP and EDP were consistently superior to all other models. The ranking of the relative influence of the determinants of SV was 1) ejecting beat ESP, 2) preceding beat ESP, 3) ejecting beat EDP, and 4) preceding beat SV.

Animals↗
PubMedDate not supplied

Tissue reaction to suture material in the feline linea alba. A retrospective, prospective, and histologic study.

Swelling and inflammation along the incision line were observed after elective ovariohysterectomy in 22 of 66 cats in a retrospective study. In a prospective study of 99 feline abdominal incisions closed with surgical gut, polyglactin 910, or polydioxanone, with and without subcutaneous closure, the least inflammation occurred when the linea alba was sutured with polyglactin 910 and the subcutaneous tissues were not sutured. Histologically, reactions in the linea alba of 12 other cats progressed from purulent to fibromononuclear to fibrous within 14 days after closure with gut, polyglactin 910, and polydioxanone. Microscopic evidence of seroma formation in 9 of 12 animals in which the subcutaneous tissue was not sutured suggested that surgical closure of subcutaneous dead space was indicated. The inflammatory reaction did not appear to be related to any one suture material as reactions were seen with all of them.

Abdominal Muscles↗
PubMedDate not supplied

Cutaneous wound healing in Ehlers-Danlos syndrome.

Wound healing in five dogs and five cats affected with a connective tissue dysplasia resembling Ehlers-Danlos syndrome of humans was compared with wound healing in 10 nonaffected animals. Six skin incisions on the lateral aspects of the thorax and abdomen of each animal were sutured and assessed daily for 75 days for evidence of healing. All wounds in nonaffected dogs, affected cats, and nonaffected cats healed by first intention. Three incisions in affected dogs had dehiscence of all or part of the incision line and healed by granulation, contraction, and epithelialization. Biopsies taken at 3, 6, 9, 12, 15, and 75 days were compared histologically to determine if there were any differences in rates of healing between affected and nonaffected animals. Epidermal thickening and scab formation were noted at days 3 and 6 in both affected and nonaffected animals. Infiltration with mononuclear cells and fibroplasia steadily increased from day 6 to day 15 in all groups. Collagen fibril formation was evident by day 9. At day 75, incision sites were recognized by fine, more compact collagen bundles and lack of adnexal structures, as compared with the adjacent dermis in both affected and nonaffected animals. Although delayed wound healing has been reported to be a complication of Ehlers-Danlos syndrome in humans, using clinical and histologic criteria, wound healing in dogs and cats with Ehlers-Danlos syndrome appears to be similar to nonaffected animals.

Animals↗
PubMedDate not supplied

Biomechanical properties of skin and wounds in Ehlers-Danlos syndrome.

The biomechanical properties of wounded and nonwounded skin were studied in three dogs and three cats affected with type I Ehlers-Danlos syndrome. Three nonaffected dogs and one nonaffected cat served as controls. Samples of wounded skin and adjacent normal skin were harvested at days 75, 138, 141, 144, 147, and 150. Samples were subjected to uniaxial tensile strength testing. Tensile strength, energy absorbed, and site of failure were recorded. In the dogs with Ehlers-Danlos syndrome, there was an increase in tensile strength in samples containing a scar over adjacent intact skin. In nonaffected dogs, affected cats and the nonaffected cat, the nonwounded skin samples had greater tensile strength. The energy absorbed by the skin samples during testing was highly correlated with tensile strength.

Animals↗