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Biomedical subjects

J A Wortman

Publications and source records attributed to J A Wortman.

13 recordsLinked to original sources

Metastasis of a well-differentiated liposarcoma in a dog and a note on nomenclature of fatty tumours.

A slow-growing mass in the left thigh of a 7-year-old spayed female fox terrier dog was originally diagnosed as an infiltrative lipoma by surgical biopsy. Necropsy findings one year later revealed multiple masses made up of well-differentiated adipocytes in the spleen, liver, lungs and a lymph node. The final histopathological diagnosis of these masses and, in retrospect, for the initial leg mass was well-differentiated liposarcoma. This case illustrates some of the confusion in current nomenclature of fatty tumours. Tumours made up of well-differentiated adipose cells which show no tendency toward invasion of surrounding tissue should be designated lipomas. We suggest that fatty tumours characterized by local tissue invasion and/or metastasis should be classified as liposarcomas. Liposarcomas may be further subdivided into well-differentiated and poorly-differentiated types.

Animals

Computed tomography, magnetic resonance imaging, and pathologic observations of the effects of intrathecal metrizamide and iohexol on the canine central nervous system.

A two-group crossover design experiment was used in eight dogs to compare the effects of intrathecally injected (0.25 mL/kg, 180 mg I/mL) metrizamide and iohexol. Additional acute observations were made in four of the dogs following a high dose (0.45 mL/kg of 300 mg I/mL) of each agent. In computed tomographic observations, there was progressive passage of each contrast medium across the interface between the cerebrospinal fluid and the brain, and statistically identical levels of each contrast medium were present in the cerebral gyri. There was a similar passage of contrast medium across the interface between the cerebrospinal fluid and the spinal cord. The rate of passage of each agent into the brain parenchyma suggested their active transport rather than a simple diffusion. In both T2-weighted magnetic resonance imaging and histopathologic studies, there was no evidence of cerebral edema following either high or low doses of each agent. In T1-weighted images made following the intravenous injection of gadolinium-DTPA (0.1 mmol/kg), the blood-brain barrier was intact.

Animals

Quantitative autoradiography of parathyroid glands in rats with carbon-14-labeled amino acids.

We have utilized a quantitative autoradiographic method as a means of evaluating amino acid uptake of the rat parathyroid gland for the ultimate purpose of finding agents potentially suitable for position emission tomographic scanning of parathyroid glands. L-[1-14C]leucine and L-[guanido-14C]arginine were evaluated because of their relatively high content in the synthetic products of the parathyroid glands compared with other neck tissues, thyroid gland, and muscle. Carbon-14 leucine disappeared rapidly from plasma following intravenous injection and there was relatively selective uptake of the [14C]leucine and [14C]arginine by the parathyroid glands when compared with uptake by the thyroid gland and neck muscle. These data suggest that both agents warrant further investigation for their potential utility in positron emission tomographic scanning of the parathyroid gland.

Amino Acids

Evaluation of canine hyperadrenocorticism, using computed tomography.

Abdominal computed tomography was performed in 9 dogs with hyperadrenocorticism and in 2 healthy dogs. Both adrenal glands were identified in all dogs. Computed tomography allowed accurate identification of the sites of adrenal gland dysfunction, when interpreted in combination with a biochemical diagnosis of canine hyperadrenocorticism. This accuracy permitted the retroperitoneal approach to be used for all adrenalectomies. Use of contrast medium (although not essential) was helpful in the computed tomographic identification of blood vessels, kidneys, and other abdominal organs.

Adrenal Cortex Neoplasms

Effect of ovarian follicles on luteal regression in heifers.

Our objectives were to determine whether or not ovarian follicles contribute to spontaneous luteal regression in heifers and, if so, when during diestrus do follicles exert their effect. Thirty-one Holstein heifers having displayed at least one estrous cycle (19 to 21 d) were assigned, as available, to randomized blocks for a factorial experiment. Reproductive organs were exposed through a midventral incision on d 9, 12 or 15 postestrus (estrus = d 0). Visible follicles were electrocauterized and both ovaries were x-irradiated (1,500 rads) in treated heifers, whereas ovaries of controls were exteriorized but follicles were not destroyed and ovaries were not x-irradiated. In two additional heifers, the ovary containing the corpus luteum was exteriorized and x-irradiated on d 15 postestrus, but follicles were not electrocauterized. Jugular blood was collected before and every 8 h after surgery until d 24 postestrus. All heifers were ovariectomized on d 24 postestrus to inventory follicles and to weigh corpora lutea. No follicles (greater than or equal to 1 mm diameter) were observed in ovaries from treated animals and concentrations of estradiol-17 beta did not change over time, whereas different numbers of follicles were observed in ovaries from controls and concentrations of estradiol-17 beta increased (P less than .05) during proestrus. Hence, treatment destroyed follicles and prevented follicular development. On d 24 postestrus, corpora lutea from treated heifers (5.5 +/- .5 g) were heavier (P less than .001) than corpora lutea from controls (1.1 +/- .1 g), independent of day when follicles were destroyed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals

Esophageal healing in the pony: comparison of sutured vs nonsutured esophagotomy.

Esophageal healing was evaluated in 10 ponies after sutured and nonsutured cervical esophagotomy techniques. Mucosal healing occurred significantly (P less than 0.005) faster after sutured esophagotomies (x = 7.5 days after surgery) than after nonsutured esophagotomies (x = 25.6 days after surgery), based on endoscopic and clinical evaluations. Although endoscopy was an accurate assessment of the return of normal passage of a food bolus through the esophagus, 4 of 10 ponies had radiographic evidence of a sinus tract after the mucosa was considered healed, based on endoscopic and clinical examinations. The surgical skin wound also healed significantly sooner after sutured esophagotomies (x = 10 days) than after nonsutured esophagotomies (x = 33.4 days). A traction diverticulum developed in all ponies with nonsutured esophagotomies, but occurred in only 1 pony with sutured esophagotomy. Minor complications were seen more frequently with sutured esophagotomy than with a nonsutured esophagotomy, but were resolved with local therapy. Saliva appeared to inhibit wound healing. All ponies were fed through esophagostomy tubes until the mucosa at the esophagotomy site was considered healed. Except for 1 sutured esophagotomy that dehisced, sutured esophagotomy was superior to nonsutured esophagotomy, because earlier establishment of a mucosal seal resulted in more rapid healing and reduced nursing care.

Animals