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Biomedical subjects

R W Dunstan

Publications and source records attributed to R W Dunstan.

51 records · Page 3Linked to original sources
PubMed1986

Inheritance of beta-mannosidosis in goats.

Plasma levels of beta-mannosidase activity were measured in the phenotypically normal members of a family of goats in which 12 cases of beta-mannosidosis have been reported. Normal or carrier genotypes were assigned on the basis of these results, and mating tables drawn up. Similar data were collected on a number of other small families unrelated to the one with beta-mannosidosis. The results indicate that the plasma beta-mannosidase level is a reasonably good indicator of carrier status and confirm that the disease beta-mannosidosis is inherited in a recessive manner and is not X-linked.

Animals↗
PubMed1984

Polytetrafluoroethylene versus autogenous vein grafts for vascular reconstruction in contaminated wounds.

A high incidence of dissolution and disruption of infected autogenous vein grafts has been demonstrated. PTFE, on the other hand, has been shown to maintain its structural integrity in the presence of well-entrenched infection, with a relatively small incidence of anastomotic disruption related to host artery necrosis. In addition, PTFE performed as well as autogenous vein when antibiotics were administered. Therefore, PTFE graft material is advocated for controlled clinical trials in patients with contaminated vascular injuries.

Animals↗
PubMed1983

Giant cell tumor of soft parts in six horses.

Giant cell tumor of soft parts was diagnosed in 6 horses 3 to 12 years old (mean, 6.8 +/- 3.5 years): 3 Quarter Horse geldings, 2 Standardbred mares, and 1 Standardbred stallion. The neoplasms developed as raised, solitary masses, approximately 1 to 4 cm in diameter, which were firmly attached to subcutaneous tissue of the neck (1 horse), shoulder (1 horse), thigh (2 horses), or stifle (2 horses). Excision was followed by local recurrence in 3 horses within 1 to 1 1/2 months. The neoplasms were firm and cut with resistance. On cut surface, they were white, with mottled red hemorrhagic areas.

Animals↗
PubMed1983

Measurement of caprine plasma beta-mannosidase with a p-nitrophenyl substrate.

Experimental conditions for measuring caprine plasma beta-D-mannosidase activity are described with p-nitrophenyl-beta-D-mannopyranoside as a substrate. The plasma enzyme was stable for 3 months at -20 C or 1 week at 4 C. The optimal pH for activity was 5.0 in citrate-phosphate or acetate buffer. Enzyme activity was linear with time up to 24 hours at 37 C, but incubation of plasma at 56 C for 5 minutes resulted in loss of all activity. The apparent Michaelis-Menten constant (Km) for the plasma enzyme was 10.0 mM. Plasma beta-mannosidase from clinically normal and beta-mannosidosis carrier goats did not differ with respect to pH optimum, heat stability, or Km. The coefficient of variation for the assay, determined by assaying a plasma pool over a 3-month period, was 10.7% (mean: 115 nmole of p-nitrophenol formed/hour/ml of plasma). The assay described can be used to evaluate plasma beta-mannosidase measurements as a test for detecting carriers of caprine beta-mannosidosis, a newly described lysosomal storage disease.

Animals↗
PubMed1983

Caprine alpha- and beta-mannosidase activities: effects of age, sex, and reproductive status and potential use in heterozygote detection of beta-mannosidosis.

Effects of age, sex, and reproductive status on caprine plasma alpha- and beta-mannosidase activities were studied. The potential use of these plasma assays was evaluated for heterozygote detection of caprine beta-mannosidosis in populations of control goats and a breeding herd composed of known and putative heterozygotes for beta-mannosidosis. In the control population, the mean plasma alpha- and beta-mannosidase activities decreased in both sexes with maturity. Male goats generally had higher plasma mannosidase activity than did females, and plasma beta-mannosidase activity was affected by the reproductive status of the goats examined. Although putative carriers in the beta-mannosidosis breeding herd could not be differentiated from age- and sex-matched controls, known carriers had plasma beta-mannosidase values intermediate between those of control and affected goats. The lack of any correlation between alpha- and beta-mannosidase activities excluded alpha-mannosidase as a reference enzyme for carrier detection, but there are still differences between known carriers and the control population with respect to the alpha- and beta-mannosidase ratio.

Age Factors↗
PubMed1982

Plasma alpha- and beta-mannosidase activities in caprine beta-mannosidosis.

Plasma alpha- and beta-mannosidase activities were measured in goats with beta-mannosidosis, a recently discovered, inherited deficiency of the glycohydrolase beta-D-mannosidase. Plasma beta-mannosidase activity in the affected animals was zero at 1 and 4 weeks after they were born. Enzyme values of age-matched, unaffected goats were between 66 and 222 nmol/hr/ml of plasma, alpha-Mannosidase activities were similar in both affected and unaffected animals. This investigation indicates that deficiency of plasma beta-mannosidases activity may be diagnostic of beta-mannosidosis.

Animals↗
PubMedDate not supplied

Gastric conduit urinary diversion in normal dogs. Part I, Upper urinary tract structure, function, and sepsis.

The urinary bladder of 10 clinically normal dogs was excised and the ureters were implanted into an isolated, vagotomized gastric segment derived from the fundic region of the stomach. The gastric segment was closed to form a conduit. Continence was maintained with a modified Kock "nipple valve" created from an isolated segment of ileum. Four dogs were euthanatized by day 30 because of complications related to the early onset of renal failure and electrolyte alterations. Six dogs were euthanatized on day 150. Ureteral dilatation, hydronephrosis, and decreased endogenous creatinine clearance rates were measured in all dogs at the end of the survival period. Pyelonephritis was diagnosed histologically in seven dogs. Positive renal cultures were obtained from seven dogs at necropsy. It was concluded that gastric conduit urinary diversion is unsatisfactory for long-term or short-term clinical use in dogs.

Animals↗
PubMedDate not supplied

The effects of thyroid hormones on the skin of beagle dogs.

The effects of hypothyroidism on canine skin were determined by comparing morphologic, morphometric, and hair cycle differences in skin biopsy samples from 3 groups of age- and gender-matched Beagle dogs: (1) euthyroid dogs; (2) dogs made hypothyroid by administration of 131I; and (3) dogs made hypothyroid and maintained in a euthyroid state by treatment with synthetic thyroxine. After 10 months of observation, there was slower regrowth of hair 2 months after clipping in the untreated-hypothyroid dogs. Untreated-hypothyroid dogs had a greater number of follicles in telogen and fewer hair shafts (ie, a greater number of hairless telogen follicles) than did the control group. The control dogs had a greater number of telogen follicles but the same number of hair shafts as the treated-hypothyroid group. Treated-hypothyroid dogs had the greatest number of follicles in the growing stage of the hair cycle (anagen). This study suggests that, at least in Beagles, induced hypothyroidism does not affect the pelage as dramatically as has been described in naturally occurring disease. This is because normal Beagles retain hair shafts in follicles for long periods, and the alopecia of hypothyroidism appears to evolve slowly because of the prolongation of this haired telogen stage. The evaluation of thyroxine-treated hypothyroid dogs demonstrates that thyroid hormone supplementation of Beagle dogs with induced hypothyroidism stimulates hair growth.

Alopecia↗
PubMedDate not supplied

Canine necrotizing sialometaplasia: a case report and review of the literature.

Necrotizing sialometaplasia (NS) is a distinct, though rare disease of the salivary glands. Histologic findings in humans and dogs are identical, but the distribution of affected glands and clinical course are very different. Small terrier breeds are predisposed. Clinically, canine NS is characterized by nausea (i.e., ptyalism, lip smacking, gulping), dysphagia, and pain in the mandibular region. Surgical removal of the affected glands produces minimal, if any, improvement; however, transient administration of anticonvulsants has resulted in dramatic clinical improvement in three cases.

Animals↗
PubMedDate not supplied

Cystic, peritoneal mesothelioma in a dog.

A 10-year-old, spayed female beagle was presented with a 2.5-year history of ascites. The ascitic fluid was a modified transudate with no abnormal cells present. Cardiac and hepatic functions were normal. Abdominal ultrasonography revealed cystic abnormalities of the peritoneal serosal surfaces. On exploratory laparotomy, the parietal and visceral peritonea were covered with variably sized, thin-walled cysts containing serous fluid. Histopathological, immunohistochemical, and ultrastructural analyses of the lesions were consistent with a diagnosis of cystic, peritoneal mesothelioma.

Animals↗
PubMedDate not supplied

A histomorphological study of sarcoptic acariasis in the dog: 19 cases.

Nineteen cases of canine sarcoptic acariasis (Sarcoptes scabiei var. canis) were diagnosed histologically by identifying sarcoptic mites present in the stratum corneum. The inflammatory responses to these mites could be staged as early, fully developed, or late lesions. No histomorphological features were identified that could serve as reliable markers of infestation in the absence of a sectioned mite.

Animals↗