PubMed Health⌕ Search

Biomedical subjects

T R Hall

Publications and source records attributed to T R Hall.

At least 19 recordsLinked to original sources
PubMed1992

Identification of mitochondrial branched chain aminotransferase and its isoforms in rat tissues.

The tissue distribution and subcellular location of branched chain aminotransferase was analyzed using polyclonal antibodies against the enzyme purified from rat heart mitochondria (BCATm). Immunoreactive proteins were visualized by immunoblotting. The antiserum recognized a 41-kDa protein in the 100,000 x g supernatant from a rat heart mitochondrial sonicate. The 41-kDa protein was always present in mitochondria which contained branched chain aminotransferase activity, skeletal muscle, kidney, stomach, and brain, but not in cytosolic fractions. In liver mitochondria, which have very low levels of branched chain aminotransferase activity, the 41-kDa protein was not present. However, two immunoreactive proteins of slightly higher molecular masses were identified. These proteins were located in hepatocytes. The 41-kDa protein was present in fetal liver mitochondria but not in liver mitochondria from 5-day neonates. Thus disappearance of the 41-kDa protein coincided with the developmental decline in liver branched chain aminotransferase activity. Two-dimensional immunoblots of isolated BCATm immunocomplexes showed that the liver immunoreactive proteins were clearly different from the heart and kidney proteins which exhibited identical immunoblots. Investigation of BCATm in subcellular fractions prepared from different skeletal muscle fiber types revealed that branched chain aminotransferase is exclusively a mitochondrial enzyme in skeletal muscles. Although total detergent-extractable branched chain aminotransferase activity was largely independent of fiber type, branched chain aminotransferase activity and BCATm protein concentration were highest in mitochondria prepared from white gastrocnemius followed by mixed skeletal muscles with lowest activity and protein concentration found in soleus mitochondria. These quantitative differences in mitochondrial branched chain aminotransferase activity and enzyme protein content suggest there may be differential expression of BCATm in different muscle fiber types.

Aging↗
PubMed1992

The pediatric patient with suspected adrenal neoplasm: which radiological test to use?

To establish which radiological test to use in a pediatric patient with suspected neoplasm, we retrospectively studied 19 children with proven adrenal neoplasm who had a combination of ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI). The results show that US should remain the initial imaging modality for evaluating abdominal masses in children but that MRI is more accurate than CT and US in detecting the organ of origin and the extent of an adrenal lesion and should, therefore, be the modality of choice for the definitive evaluation of adrenal neoplasm in children.

Adolescent↗
PubMed1992

Congenital bladder rupture and urine ascites secondary to a sacrococcygeal teratoma.

A case of congenital bladder rupture with urine ascites and bilateral hydronephrosis secondary to a sacrococcygeal teratoma obstructing the bladder outlet is presented. As no evidence of pulmonary hypoplasia and renal dysplasia was present, with rapid recovery of renal function after decompressive surgery, the infravesical obstruction probably occurred late in the fetal period. The bladder rupture resulting in internal decompression may have constituted an additional protective mechanism for the preservation of renal function.

Ascites↗
PubMed1992

Thyroid and adrenal function in the ring dove (Streptopelia risoria) during food deprivation and a breeding cycle.

The concentration of plasma triiodothyronine (T3), thyroxine (T4), corticosterone, and glucose as well as body weight and food intake were measured in pairs of ring doves throughout a breeding cycle and during food deprivation. During courtship and incubation the levels of plasma T4 were significantly higher in males than in females. A transitory decrease in food intake in both sexes was measured at the onset of incubation but was not associated with a change in body weight or in levels of plasma thyroid hormones. After the eggs had hatched, food intake increased but was associated with a reduction in body weight and concentrations of plasma T3 and T4, although plasma corticosterone and glucose both increased. Food deprivation for 48 hr resulted in a significant fall in the concentration of plasma T3 and an increase in plasma corticosterone. These changes suggest that all the food was not being digested by the adult birds during brooding but was almost exclusively regurgitated to feed the squabs.

Adrenal Glands↗
PubMed1992

Subperiosteal resorption: effect of full-frame image compression of hand radiographs on diagnostic accuracy.

Image compression is essential to handle a large volume of digital images, including computed tomographic, magnetic resonance, computed radiographic, and digitized images in a digital radiology operation. Developed during the past few years, full-frame bit allocation performed with the cosine transform technique has been proved to be an excellent irreversible image compression method. This article describes the effect, on the accuracy of diagnosis of subperiosteal resorption, of using the hardware compression module to produce hand radiographs. Receiver operating characteristic analysis of the interpretation of 71 radiographs by five observers demonstrated that there is no statistically significant difference in diagnostic accuracy between the original radiographs and compressed and reconstructed images obtained with a compression ratio as high as 20:1.

Bone Resorption↗
PubMed1992

Isolation of the fourth ventricle causing transtentorial herniation: neurosonographic findings in premature infants.

OBJECTIVE: Significant posthemorrhagic enlargement of the fourth ventricle occurs only in a small minority of patients. Although entrapment or isolation of any ventricle can occur, the fourth ventricle is the most common site. This study was undertaken to better understand enlargement of the fourth ventricle after intraventricular hemorrhage and the neurosonographic features of isolation and transtentorial herniation. MATERIALS AND METHODS: The sonographic records of 1535 premature neonates were reviewed for evidence of intracranial hemorrhage and ventriculomegaly. Cranial sonography was performed within the first 3 days of life in all neonates born in our hospital and within the first week of admission for transferred neonates. Follow-up sonograms were obtained at weekly intervals until discharge from the nursery. Intracranial hemorrhages were classified as severe when the hemorrhage was associated with hydrocephalus, intraparenchymal hemorrhage, or both. RESULTS: Intracranial hemorrhage occurred in 761 (50%) of 1535 patients, with severe hemorrhages in 229. Ten had massive enlargement of the fourth ventricle with isolation in six of the 10 after shunt placement. Isolation of the fourth ventricle causing transtentorial herniation occurred in three. Of the patients with isolation of the fourth ventricle, two had associated infection and ventriculitis caused by Klebsiella oxytoca and one had Candida ventriculoencephalitis. CONCLUSION: The early recognition of the neurosonographic features of an enlarged fourth ventricle causing transtentorial herniation has important therapeutic implications. Although isolation can occur after intraventricular hemorrhage alone, infection and ventriculitis are significant factors in the development of an isolated fourth ventricle.

Cerebral Hemorrhage↗
PubMed1992

Identification and partial purification of serum growth hormone binding protein in domestic animal species.

The chemical nature and variations in serum concentrations of growth hormone binding protein (GHBP) from humans, rabbits, and rodents have been reported. To date little is known about the GHBP of domestic animals. Therefore, we initiated these studies to determine whether a serum GHBP was present in domestic animals and to purify the binding protein (BP) from serum of selected species. Using a dextran-coated charcoal separation assay, specific growth hormone (GH) binding was demonstrated in ovine, bovine, chicken, human, goose, porcine, and equine serum (listed in sequence from lowest to highest binding). Variation in BP activity was relatively high, both within and between species. Yearling ewes had higher serum GHBP than either prepubertal (4 mo) or older (5 yr) ewes. The GHBP was partially purified from chicken, ovine, and porcine serum using GH affinity chromatography. These BP had high affinity (Ka = 2 x 10(8) to 2 x 10(9) L/mol, depending on species) and low capacity (2 x 10(-10) to 5 x 10(-11) mol/unit of protein) for human GH but showed lower binding affinity for homologous GH (Ka = 2 x 10(7) L/mol). The porcine GHBP had the highest and ovine GHBP the lowest affinity for human GH. Other heterologous somatotropic hormones, ovine placental lactogen, and ovine GH displayed higher binding affinity to chicken and pig BP than the respective homologous hormones. Further chromatographic purification of the porcine GHBP resulted in an additional 1,000-fold purification. The estimated molecular weight of porcine GHBP is 50,000 to 60,000 Da. These results demonstrate that the serum from all domestic species tested contains a specific GH-binding moiety and that under the conditions described here human GH is a more efficient ligand than the homologous hormone.

Animals↗
PubMed1991

Failure of duplex sonography to diagnose hepatic artery thrombosis in a high-risk group of pediatric liver transplant recipients.

Excellent correlation between angiographic findings and duplex sonography has been previously reported in the diagnosis of hepatic artery thrombosis (HAT), the most common technical complication of pediatric orthotopic liver transplantation (OLT). We now report a significant incidence of false-negative sonograms, ie, hepatic artery reported as patent but thrombosed on subsequent angiography. HAT was diagnosed in 10 of 57 pediatric OLT recipients evaluated prospectively by duplex sonography. In 5 patients HAT was diagnosed only by angiography even though arterial wave forms were observed on duplex sonography. Selective angiography demonstrated extensive collateral vessel formation arising from the superior mesenteric artery, the celiac axis, or both. The 5 patients shared very similar clinical courses marked by relapsing bacteremias with multiple enteric organisms, associated with focal infarctions of the liver. Four of the grafts had difficult arterial reconstructions and 3 of 5 had segmental bile duct dilation. We conclude that duplex sonography has proven to be a valuable screening tool in evaluating hepatic artery patency but must be correlated with angiography studies in a high-risk group of pediatric transplant patients characterized clinically by relapsing bacteremia and radiographically by false-negative duplex examinations.

Child↗
PubMed1991

Pulmonary edema and fluid mobilization as determinants of the duration of ECMO support.

The physiological variables that govern recovery of pulmonary function during neonatal extracorporeal membrane oxygenation (ECMO) remain poorly understood. We hypothesized that pulmonary hypertension (PHN) resolves soon after starting ECMO and that neonatal weight gain, pulmonary edema, and fluid mobilization are major determinants of recovery of pulmonary function and the ability to decrease ECMO support. To evaluate this, 17 consecutive neonates requiring ECMO for severe respiratory failure were reviewed. PHN was studied by daily echocardiography to assess the direction of ductal shunting. To evaluate fluid flux, pulmonary function, and edema during ECMO, we measured body weight, urine output, and ECMO flow every 12 hours. To evaluate pulmonary edema, serial chest radiographs obtained every 12 hours were randomly reviewed and scored by two radiologists with a semiquantitative chest radiograph index score (CRIS). By 25% of bypass time, PHN had resolved in all patients. However, at that time, weight had increased to 9.16% +/- 1.78% above birth weight, and the CRIS was 44% worse than the value just prior to ECMO. From 25% time on bypass, as urine output increased, patient weight and CRIS progressively decreased, allowing ECMO support to be weaned. At the time of discontinuation of ECMO support, weight had decreased to 2.0% +/- 1.3% above birth weight, and urine output remained steady at 3.0 +/- 0.3 mL/kg/h. Within 24 hours of stopping ECMO, the CRIS showed a 58% improvement compared to maximal scores during ECMO. We conclude that PHN decreases early in ECMO and that edema and its mobilization are important determinants of the improvement in pulmonary function and duration of ECMO.(ABSTRACT TRUNCATED AT 250 WORDS)

Body Fluids↗
PubMed1991

A case report of Drash syndrome in a 46,XX female.

Progressive renal insufficiency, male pseudohermaphrotidism, and Wilms tumor are known as the triad of Drash syndrome. The renal involvement has been reported in association with Wilms tumor with or without pseudohermaphroditism. The nephropathy progresses rapidly, is unresponsive to steroids, and eventually requires dialysis. The case we report is a 46,XX phenotypic female child who had diffuse mesangial sclerosis (DMS) and developed Wilms tumor 3 years after initiating dialysis for end-stage renal disease (ESRD). Any child presenting with DMS should be considered at risk for development of Wilms tumor and should be investigated for the presence of XY gonadal dysgenesis. Once ESRD develops in such a child, prophylactic nephrectomy and possibly gonadectomy should be undertaken.

Child, Preschool↗
PubMed1990

Purification of branched chain aminotransferase from rat heart mitochondria.

This paper presents the first purification of the branched chain aminotransferase (EC 2.6.1.42) from rat heart mitochondria. The enzyme has been purified from the 100,000 x g supernatant obtained after sonication and ultracentrifugation of rat heart mitochondria. A combination of open column chromatography, high pressure liquid chromatography (HPLC), and discontinuous polyacrylamide disc gel electrophoresis was used. The key step in the procedure was hydrophobic interaction chromatography on HPLC. The final purification step was polyacrylamide disc gel electrophoresis where the enzyme appeared as a doublet. When electroeluted from the gel, each of these bands had the same specific activity demonstrating that there are two forms of the purified enzyme which differ slightly in electrical charge. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, these two enzyme forms appeared as a single band with a molecular mass of 43 kDa. Size exclusion chromatography on Sephacryl S-100 identified the enzyme as a 50-kDa protein. These experiments argue against the existence of a dimeric form of this enzyme. The ratio of enzyme activity with leucine (0.84), valine (0.88), or glutamate (0.66) as amino acid substrate versus isoleucine remained constant throughout the purification procedure. Specific activity of the final preparation was 66 units/mg of enzyme protein. Polyclonal antibodies against the purified enzyme were raised in rabbits. On an immunoblot the antiserum recognized a 43-kDa protein in the 100,000 x g supernatant from a rat heart mitochondrial sonicate but did not recognize any proteins in rat brain cytosol. Quantitative immunodot assay resulted in an estimated enzyme content of about 100 micrograms of branched chain aminotransferase protein/g of heart, wet weight. Finally, 97% of the heart branched chain aminotransferase activity could be neutralized by the antiserum, but the antiserum would not neutralize aminotransferase activity in brain cytosol. These data suggest that close sequence homology does not exist between the two proteins.

Animals↗
PubMed1990

Magnetic resonance imaging of pediatric musculoskeletal trauma.

MRI is an important tool for evaluating acute and chronic injuries to the musculoskeletal system. It is effective in demonstrating abnormalities in the knee and hips and in detecting bone and ligamentous trauma that is not evident radiographically.

Bone Marrow↗
PubMed1990

False-negative duplex Doppler studies in children with hepatic artery thrombosis after liver transplantation.

Recent reports describe formation of collateral vessels in children who have hepatic artery thrombosis after liver transplantation. This led us to reevaluate the role of duplex Doppler imaging in this population. Among 135 pediatric liver transplant patients, 20 had arteriography for suspected hepatic artery thrombosis. Duplex and/or color Doppler imaging was performed in 13 of these children. The Doppler examination failed to show hepatic artery signals in five patients. Arteriography showed hepatic artery thrombosis in all five. In three of these, subsequent Doppler examinations showed reappearance of arterial Doppler signals. Arteriography confirmed the interval development of collaterals. Hepatic artery signals were found on the Doppler examinations of the remaining eight patients. Four had normal arteriograms, but the remaining four had hepatic artery thrombosis with collateral formation. Patients with hepatic artery thrombosis and collateral circulation tended to have increased diastolic flow (decreased resistive index). In addition, early scans clearly identified patients with complete thrombosis before collateral formation. On the basis of our preliminary experience, a child with a liver transplant and a clinical history strongly suggestive of hepatic artery compromise should have arteriography despite an apparently normal Doppler examination.

Child↗