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Biomedical subjects

M F Bryson

Publications and source records attributed to M F Bryson.

16 recordsLinked to original sources

Energy-dependent transport of nickel by Clostridium pasteurianum.

The mechanism of nickel transport by Clostridium pasteurianum was investigated by using 63NiCl2 and a microfiltration transport assay. Nickel transport was energy dependent, requiring either glucose or sucrose; xylose and o-methyl glucose did not support growth, butyrogenesis, or transport. Transport was optimum at pH 7 and 37 degrees C, and early-stationary-phase cells had the highest propensity for nickel transport. The apparent Km and Vmax for nickel transport approximated 85 microM Ni and 1,400 pmol of Ni transported per min per mg (dry weight) of cells, respectively. On the basis of metal specificity, nickel appears to be transported primarily by a magnesium transporter, although an alternative nickel transporter may also be involved. ATPase inhibitors (N,N'-dicyclohexylcarbodiimide, tributyltin chloride, 7-chloro-4-nitrobenz-2-oxa-1,3-diazole, and quercetin), protonophores (carbonyl cyanide m-chlorophenylhydrazone, 2,4-dinitrophenol, and gramicidin D), metal ionophores (valinomycin, monensin, and nigericin), benzyl viologen, carbon monoxide, and oxygen inhibited nickel transport. Nickel transport was coupled indirectly to butyrogenesis and was dependent on the energy state of the cell.

Biological Transport, Active

Glomerular lesions in patients with late-onset cystinosis with massive proteinuria.

3 siblings--2 brothers aged 18 and 13 years, and 1 sister, aged 11 years--with adolescent or late-onset cystinosis presented with massive proteinuria. At the time their glomerular filtration rate was normal or only modestly diminished. Though glomerular injury was evident, renal tubular functional abnormalities were also present. Renal biopsy revealed histopathologic features typical of the nephropathic form of cystinosis with the Fanconi syndrome: polykaryocytosis, varying degrees of glomerular sclerosis, thickening and reduplication of basement membrane, fused foot processes, dilated tubules with altered epithelial cell features, and interstitial fibrosis. Fine granular deposits of C3 and IgM are irregularly distributed in the glomeruli, findings which have not been described in cystinosis. These deposits are possibly immune complexes being deposited in the glomeruli unrelated to the cystine-storage disease or they may represent a localized activation of the complement system induced by the glomerular injury of cystinosis.

Adolescent

Systemic amyloidosis in cystic fibrosis.

We report two siblings with cystic fibrosis and systemic amyloidosis. The major clinical problem in both cases was recurrent respiratory infection with pulmonary fibrosis and bronchiectasis prior to death at ages 20 and 22 years. Findings from postmortem examinations disclosed diffuse amyloidosis. In addition, amyloid infiltration developed in both patients, with enlargement of the thyroid gland, and one required thyroidectomy. An autopsy review of 17 additional cases of cystic fibrosis failed to disclose any other instances of systemic amyloidosis.

Adult

Testosterone-estradiol-binding globulin in patients with Turner's syndrome: effects of estrogens and acute growth hormone administration.

The TeBG activity of plasma from patients with Turner's syndrome was measured quantitatively using polyacrylamide gel electrophoresis. Human growth hormone administration did not significantly change the plasma TeBG levels. However, oral replacement therapy with estrogens elevated plasma TeBG within 3 days; after 9 days these levels reached a maximum of three- to four-fold greater than that observed at a time prior to therapy.

Adolescent

Postadrenalectomy pituitary adenoma (Nelson's syndrome) in childhood: clinical and roentgenologic detection.

Following total adrenalectomy in Cushing's syndrome associated with adrenal hyperplasia, but not with adrenal adenoma or malignancy, elements of the pituitary may be stimulated to grow rapidly and even aggressively. There is strong evidence to support the idea that there is a pre-existing tumor in many, if not all, of these cases. In some, the tumor may be too small to deform the sella turcica. After adrenalectomy, these patients should be observed carefully and frequently for hyperpigmentation, visual field defects, and sella turcica enlargement.

Adenoma