Biomedical subjects
Publications and source records attributed to R G Brown.
Experience with 22 cases of reconstruction of the cervical esophagus, hypopharynx and oral cavity using free jejunal transfer is presented. The method requires an experienced team with high technical competence, but the benefits related to rapid single-stage completion and low morbidity certainly justify its use.
A patient is described who demonstrated accumulation of Tc-99m-sulfur colloid in both the lung and kidney following treatment for disseminated intravascular coagulation. This phenomenon has been demonstrated experimentally in animals following the induction of disseminated intravascular coagulation, but to our knowledge has not been previously described in humans.
When Cryptococcus laurentii is grown on 3-O-methyl-D-glucopyranose (3-O-MeGlc), two metabolic products are methanol and an extracellular mannan. Hydrolysis of the mannan produced during growth on 3-O-MeGlc labelled with 14C in the 1 or 6 position yields mannose with retention of the labelling pattern in the carbon chain. O-Methyl-labelled substrate yields radioactive methanol. Three possible mechanisms of O-demethylation are ether cleavage, peroxidatic attack, and beta-elimination. The latter mechanism was shown to be the most likely through the use of double-labelled (3H and 14C) 3-O-MeGlc.
3-O-Methyl-D-glucose (3-O-MeGlc) or a mixture of 3-O-MeGlc and glucose stimulate invertase, beta-glucosidase, alpha-glucosidase, and alpha-galactosidase production by Cryptococcus laurentii. They also increase invertase and alpha-glucosidase production by Saccharomyces cerevisiae. The stimulatory effect of 3-O-MeGlc is not caused by competition with glucose for transport nor by a direct action on glycosidases. It is proposed that 3-O-MeGlc acts as a structural rather than as a functional analogue of glucose displacing it from regulatory sites to relieve catabolite repression. Evidence is presented suggesting that intracellular cAMP levels may be related to the effect of 3-O-MeGlc.
Scintigraphy in 3 patients with chondroblastoma showed that the tumors were hyperemic and avidly accumulated the radionuclide. These changes were also present in adjacent normal bone, but to a lesser degree. This suggest that radionuclide uptake in chondroblastoma is a function of the blood supply to the tumor rather than primary matrix extraction.
An ultrastructural study was made of the changes occurring within the gastrocnemius insertion of normal and selenium-deficient ducklings from 1 to 12 days of age. The cytologic characteristics of the fibroblasts, vessels, collagen, and muscle cells are described. Those exposed to the selenium deficiency showed major alterations of all components. The fibroblasts showed changes ranging from collapsed cisternae and degenerating mitochondria to rupture. The capillary endothelium was abnormal, as was the smooth muscle of arteriolar walls. The collagen sizes were altered, and the muscle cell termini showed major pathologic changes. The above alterations occurred within 4 days of exposure of the deficiency. The muscle cells of the body portion of the gastrocnemius showed no alterations until Day 8. The observations present evidence that indicates that connective-tissue-vascular abnormalities precede myopathic changes in nutritionally induced dystrophy. The significance of these findings is discussed with respect to the etiology of nutritionally induced dystrophy.
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1. Hepatic proteins isolated from control kennel dogs bound small quantities of zinc and iron and the peptide fraction contained neither metal. 2. Zince loading of kennel dogs stimulated an hepatic uptake of five times more zinc and three times more iron than an equivalent copper load. The increase in metal concentration was noted in the 10,000 dalton protein. 3. Both the 12,000 and 10,000 dalton proteins isolated from kennel dogs contained more binding sites specific for zinc than for either copper or iron. All three proteins isolated from Alaskan Malamutes showed a smaller affinity for zinc than copper or iron. 4. Both copper and zinc loading stimulated an uptake of [14C]glucosamine and [3H]serine from the peptide fraction of control kennel dogs into the 10,000 dalton protein.
1. Three low molecular weight (12,000, 10,000 and 7,000) metal binding proteins have been isolated from the livers of normal and chondrodysplastic Alaskan Malamutes. 2. Comparison studies between kennel (mixed breed) dogs and both adult and immature Alaskan Malamutes suggested that the disturbance in trace mineral metabolism found in the Malamutes is almost entirely reflected in the 12,000 mol. wt species. 3. The major copper-inducible protein (10,000 mol. wt) observed in kennel dogs was not found to be inducible in Malamutes and contained constant ratios of both copper and zinc to protein in metal binding proteins isolated from the livers of both normal and dwarf Malamutes. 4. The copper and zinc found in the UM2 concentrates (mol. wt greater than 2000) of immature Malamutes showed very little affinity to the proteins and these metals were found chiefly in a peptide fraction which apparently serves as a reservoir from which the storage proteins obtain the metals that they bind. 5. Regression analysis indicated a statistically significant correlation between both copper and zinc concentrations and the carbohydrate concentration in the proteins investigated.
Hydroxyproline-poor glycoprotein contains a single polypeptide chain with lysine at the N-terminus. Removal of carbohydrate attached to serine by alkali treatment produces two polypeptide fractions. Labeling with (35)S indicates that most serine residues having a carbohydrate substituent removed by alkali occur on the polypeptide fraction of lower molecular weight. Following alkali treatment, two additional N-terminal amino acids, proline and glycine, were detected suggesting that alkali treatment also cleaves peptide bonds. Methylation analysis of native and degraded glycoproteins, extracted 24, 27, and 36 hours after wounding, demonstrates the following structural features of carbohydrate attached to serine. Arabinose may be (1 --> 2)-, (1 --> 3)-, or (1 --> 5)-linked, glucose occurs as a chain of beta-(1 --> 4)-linked residues, and galactose occurs as a nonreducing terminal unit.
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Samples of pig blood were taken in relation to feeding and assayed for intestinal CaBP by radioimmunoassay. When heparinized plasma was assayed by a double-antibody technique, significant postprandial increases of plasma immunoreactivity between twofold and 10-fold were noted. These apparent feeding responses were seen only with heparinized plasma and not with EDTA plasma, ACD plasma, or serum. Nor were such responses seen when heparinized plasma was assayed with talc or charcoal methods for phase seperation. The height of the artefactual response in immunoreactivity following feeding was related to the amount of carrier serum added during the incubation with second antibody and with the duration of this incubation. The artefact was seen in the presence of 0.01M EDTA. These results demonstrate a striking postfeeding radioimmunoassay artefact localized to the second-antibody precipitation step. The artefact can easily be avoided by several methodological changes. Such an artefact could conceivably affect other double-antibody radioimmunoassays of hormones or other substances. Caution is advised when double-antibody radioimmunoassays are used to assay samples taken in relation to feeding.
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The transverse lumbosacral back flap is presented as a good one to use for coverage of sacral defects. Its reliability appears to be due to an axial pattern of its proximal portion, and to an uninterrupted subdermal vascular plexus across the midline of the back (supplying the terminal portion). A retrospective analysis of its use in 20 patients, over the last 3 years, suggests that when it is designed properly it can be most useful in the management of sacral pressure sores.
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