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Biomedical subjects

J W Tyler

Publications and source records attributed to J W Tyler.

At least 55 records · Page 3Linked to original sources
PubMed1997

Tetraparesis due to vertebral physeal fracture in an adult dog with congenital hypothyroidism.

A four-year-old male affenpinscher was referred for evaluation of hindlimb weakness that had progressed to tetraparesis over a period of four weeks. Neurological examination was suggestive of a cervical spinal cord lesion. Radiographic examination revealed diffuse skeletal immaturity with open physes and epiphyseal dysplasia in long bones and vertebrae, consistent with a diagnosis of congenital hypothyroidism. Total and free serum T4 concentrations were very low, indicative of hypothyroidism. Survey radiographs of the cervical spine revealed a dorsally displaced Salter-Harris type I fracture of the cranial portion of the fourth cervical vertebra with the endplate present in the vertebral canal. Although signs of transverse myelopathy are uncommon in dogs with congenital hypothyroidism, they may be associated with either intervertebral disc protrusion or endplate displacement into the vertebral canal secondary to the epiphyseal abnormalities associated with congenital hypothyroidism.

Animals↗
PubMed1997

Stability of gamma-glutamyltransferase activity in calf sera after refrigerated or frozen storage.

OBJECTIVES: To examine stability of -glutamyltransferase (GGT) activity in stored serum from neonatal calves. ANIMALS: 10 commercial beef calves between 36 and 60 hours old. PROCEDURE: Serum samples were obtained from the calves, and each sample was divided into 8 aliquots. Serum GGT activity was measured on day 0 (fresh) and days 1, 2, 3, and 4 of refrigerated storage (4 C) and weeks 1, 2, and 3 of frozen storage (-20 C). RESULTS: Serum GGT activities for each of the refrigerated aliquots did not significantly differ from day zero, with serum GGT activity (expressed as a percentage of initial activity) > 99% on all 4 days. Serum GGT activity in frozen aliquots decreased significantly after 1 and 2 weeks of frozen storage, 97 and 98%, respectively; however, this decrease in GGT activity was not biologically significant. The observed GGT activity did not decrease significantly in the samples stored frozen for 3 weeks; these samples retained 99% of initial activity. CONCLUSION: The observed stability of serum GGT activity indicates that serum may be obtained, stored, and batch processed at a later time. This stability during storage is important to the success of a bovine passive transfer monitoring program based on GGT activity.

Animals↗
PubMed1996

Prediction of calf mortality by use of tests for passive transfer of colostral immunoglobulin.

OBJECTIVE: To examine the ability of several commonly used tests for evaluation of passive transfer of immunoglobulin to predict mortality in dairy replacement heifers. DESIGN: Prospective observational study. ANIMALS: 246 dairy replacement heifers between 1 and 8 days of age. PROCEDURE: Using serum samples obtained from each calf, total serum protein concentration and results of zinc sulfate turbidity, sodium sulfite turbidity, radial immunodiffusion, and glutaraldehyde coagulation were determined. Calves were monitored for 100 days, and relative risks for death were calculated. Logistic regression models predicting death also were developed. RESULTS: None of the logistic regression models detected a significant association between test results and mortality. The greatest relative risks of mortality were observed in calves with serum protein concentrations < 4.5 g/dl, serum IgG1 concentrations < 500 mg/dl, and sodium sulfite test scores < 1+. CLINICAL IMPLICATIONS: Calves with lower passive transfer values had increased risk of death; however, failure of passive transfer is not an infallible predictor of mortality.

Animals↗
PubMed1996

Effect of craniectomy, durotomy, and wound closure on intracranial pressure in healthy cats.

OBJECTIVES: To establish intracranial pressure (ICP) measurements in healthy cats under isoflurane anesthesia, using a fiberoptic monitoring system; to assess brain lesions associated with such monitoring; and to determine whether decompressive intracranial surgery decreases ICP in healthy cats. ANIMALS: 6 healthy cats. PROCEDURE: Craniectomy and durotomy were performed, and the effect of these procedures on ICP was determined. ICP was monitored by use of a fiberoptic monitoring system. Gross and microscopic evaluations of brain tissues were performed after data collection. RESULTS: ICP decreased significantly after craniotomy and durotomy. After wound closure, ICP remained significantly reduced relative to initial pressures. However, postsurgical pressures were significantly increased, compared with those associated with ICP after durotomy. Gross and histologic abnormalities associated with placement of the ICP monitoring cable included mild focal acute hemorrhage and mechanical cortical disruption. CONCLUSIONS: Craniectomy and durotomy significantly decreased ICP in healthy cats. ICP increased after wound closure, but remained significantly lower than initial pressures. CLINICAL RELEVANCE: Craniectomy and durotomy may be used to decrease ICP in cats.

Animals↗
PubMed1996

Optimizing performance of a qualitative zinc sulfate turbidity test for passive transfer of immunoglobulin G in calves.

OBJECTIVE: To determine optimal zinc sulfate test solution concentration for detecting failure of passive transfer in calves. ANIMALS: 235 calves (1 to 8 days old) from a calf-rearing operation in central Washington state. PROCEDURE: Zinc sulfate turbidity tests, using 200-, 250-, 300-, 350-, and 400-mg/L test solutions, were performed on calf serum. These increasing concentrations were evaluated for detection of failure of passive transfer. Using 1,000 mg of IgG1/dl as the threshold for adequate passive transfer, sensitivity, specificity, and accuracy of classification were determined by comparing the zinc sulfate test results with serum IgG1 concentration (mg/dl) measured by radial immunodiffusion. RESULTS: The 200-mg/L zinc sulfate turbidity test solution was 100% sensitive; however, specificity was only 25.5%. Increasing concentrations of zinc sulfate test solution up to 350 mg/L improved specificity with either no change or small decreases in sensitivity. CONCLUSION AND CLINICAL RELEVANCE: The endpoint of the traditional 208-mg/L zinc sulfate turbidity test for failure of passive transfer in calves is too high. Increased test solution concentrations improve specificity with only minor adverse effects on sensitivity.

Animals↗
PubMed1995

Left oblique celiotomy approach for cesarean section in standing cows.

A left oblique celiotomy approach was used for cesarean section in 18 standing cows (15 beef cows and 3 dairy cows). Indications for cesarean section included oversized or emphysematous fetus and uterine inertia. Poor body condition was identified as a contributing factor for dystocia in 4 cows. Abdominal wall hernias did not develop in any of the cows. Because the incision in this approach extends further cranial and ventral than in the standard left celiotomy approach, the left oblique celiotomy readily permitted manipulation and exteriorization of the gravid uterine horn. Additionally, apposition of the transversus abdominis and internal abdominal oblique muscles was facilitated by use of this technique. Closure of the incision was readily accomplished in all cows.

Abdominal Muscles↗
PubMed1995

Accuracy of microchip identification in dogs and cats.

A study was performed to determine the sensitivity and specificity of a commercially available microchip identification system approximately 1 year after implantation in dogs and cats. Thirty-three dogs and 16 cats in which a microchip had been implanted and 31 dogs and 18 cats in which a microchip had never been implanted were included in the study. In cats, sensitivity and specificity of microchip identification were 1.00. In dogs, sensitivity and specificity were 0.97 and 1.00, respectively. The chip had migrated in the 1 dog with a false-negative result, but the chip remained functional, and identification was established in this dog following closer physical examination and scanning.

Animal Identification Systems↗