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Biomedical subjects

G Hoag

Publications and source records attributed to G Hoag.

11 recordsLinked to original sources
PubMed1992

High incidence of significant urinary ascorbic acid concentrations in a west coast population--implications for routine urinalysis.

Examination of 4379 routine urinalysis specimens with dipsticks sensitive to ascorbic acid showed that 22.8% were positive specimens. The mean urinary vitamin C concentration in this population was 2120 mumol/L. There was a high rate of false-negative dipstick results for hemoglobin in patients with vitamin C in the urine. The highest false-negative rates were observed in urine samples containing less than 50 erythrocytes per high-power field. In further experiments when volunteers consumed supplemental oral USP vitamin C at doses of 100, 250, 500, and 1000 mg or vitamin C-containing fruit juices, even the lowest doses of oral vitamin C or juice resulted in sufficient urinary vitamin C to produce false-negative dipstick results in hemoglobin and glucose testing. To prevent potentially dangerous false-negative results, screening urinalysis protocols relying only on dipstick testing should include a check for urinary vitamin C or use a dipstick that is not subject to vitamin C interference.

Ascorbic Acid↗
PubMed1988

Erythrocyte abnormalities in a hypoalphalipoproteinemia syndrome resembling fish eye disease.

Erythrocyte membrane (EM) abnormalities in a 16-yr-old boy with hypoalphalipoproteinemia resembling fish eye disease (FED-LS) were investigated. The proband's erythrocytes had markedly decreased osmotic fragility with target cells observed in the peripheral film. Analysis of his EM lipids revealed normal cholesterol and phospholipid content but a marked increase in phosphatidylcholine with concomitant decreases in phosphatidylethanolamine and sphingomyelin. Of the EM enzymes examined, acetylcholinesterase and superoxide dismutase activities were decreased while those of Na+-K+ ATPase, catalase and glutathione reductase were normal. 51Cr erythrocyte survival in the patient was slightly decreased. The observed changes in a number of structural and functional properties of erythrocytes in this disorder are indistinguishable from those previously described in homozygotes for familial lecithin:cholesterol acyltransferase (LCAT) deficiency. Thus, it is possible that in both of these disorders an abnormality of plasma LCAT activity causes, either directly or indirectly, functional and structural changes in the erythrocyte membrane.

Adolescent↗
PubMed1987

Hypoalphalipoproteinemia resembling fish eye disease.

A 16-year-old boy presented with bilateral arcus cornealis and markedly decreased plasma high density lipoprotein cholesterol. The plasma lipoprotein abnormalities, as well as decreased mass and activity of lecithin:cholesterol acyltransferase (LCAT), were similar to those described in patients with fish eye disease. Increased number of target cells and decreased osmotic fragility of the proband's erythrocytes were noted. The proband's father and one of his brothers showed intermediate plasma lipoprotein and LCAT alterations. The father's erythrocytes also showed abnormal osmotic fragility. The mother of the propositus had normal plasma lipoproteins and erythrocyte osmotic fragility, but her LCAT activity was also low. Many of these features suggest a disorder similar to fish eye disease which is clinically and biochemically distinct from other hypoalphalipoproteinemias.

Adolescent↗
PubMed1986

Astroblastoma revisited: a report of three cases.

The very existence of astroblastoma has been a question of considerable controversy, although there appears now to be sufficient documentation to establish it as a tenable entity. Due to the rarity of this tumor, little information exists in the literature as to its natural history, efficacy of therapy and its pathological and radiological appearance. We report three cases of astroblastoma, describing their natural history, the response to therapeutic interventions and their light microscopic, ultrastructural and immunohistochemical characteristics.

Adult↗
PubMed1986

Malignant intracranial fibrous histiocytomas. Histologic, ultrastructural and immunohistochemical studies of two cases.

Two cases of malignant intracranial fibrous histiocytoma are presented. In Case 1 the tumour arose from the meninges and showed a disseminated spread throughout the neuroaxis. In the second case the tumour appeared to arise from within the brain substance. In this case surgical intervention and radiotherapy appeared to have achieved a cure, since no residual tumour was found at autopsy. The tumours were examined using ultrastructural and immunohistochemical techniques, which appeared advantageous in delineating this rare tumour from other intracranial neoplasms.

Aged↗
PubMed1978

The production of creatine kinase isozyme BB in sera of a patient with prostatic carcinoma and in tumor homogenates.

1. A CK(BB) fraction was observed in sera of a patient with prostatic carcinoma. The fraction accounted for 59% of the total enzyme activity. A metastatic tumor of a prostatic carcinoma was observed to contain solely the CK(BB) isozyme. An embryonal testicular carcinoma was observed to have a higher percentage of the CK(BB) fraction when compared to the adjacent tumor free testicular tissue in a third patient. These studies suggested that in certain carcinomas there are tissue isozyme modifications at the molecular level. The isozymic modification was suggested as a reversion towards an embroyonic pattern as the adult molecular form tended to disappear while the fetal form increased. This too suggests that the isozymes of CK may be a useful model in elucidating the mechanism through which this transition occurs. 2. The high percentage of CK(BB) in the sera of the patient with metastasis was discussed. The origin could not be determined, but either a primary tumor or a metastatic tumor by their enzyme modifications could account for this increased fraction in sera.

Adult↗
PubMedDate not supplied

Shy-Drager syndrome: the transitional variant.

The clinicopathological features of a patient with the transitional variant of the Shy-Drager syndrome is described. The only previously reported case of the transitional variant was reexamined and pathological similarities to the present case are reviewed. Both patients exhibited features of Parkinson's disease with Lewy bodies in the substantia nigra and locus ceruleus. Striato-nigral degeneration and olivo-ponto-cerebellar atrophy were evident in both cases. They can thus be considered as transitional forms of the Shy-Drager syndrome with feature of both Parkinson's disease and multiple system atrophy.

Aged↗