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Biomedical subjects

H S Loh

Publications and source records attributed to H S Loh.

At least 55 records · Page 3Linked to original sources

A case of Ludwig's angina following tooth extraction.

Ludwig's angina developed in an adult Chinese male following a mandibular third molar extraction. Brawny and tender swellings of the floor of the mouth and neck, with the elevation of the tongue, were classically present. The management of this case was based on the current emphasis of early broad-spectrum and antibiotic therapy with the maintenance of an adequate airway. The role of dental infection in this condition was highlighted.

Ampicillin↗

Changes in the fine structure of the testicular Leydig cells of the seasonally-breeding bat, Myotis adversus.

Leydig cells of the bat, Myotis adversus, have been examined by electron microscopy throughout fourteen months. During the breeding season the Leydig cells become hypertrophied and are characterised by prominent areas of agranular endoplasmic reticulum and numerous small, membrane-bound granules. Microperoxisomes are also observed. During the period of testicular regression. Leydig cell size and the number of membrane-bound granules are greatly reduced. Lipid droplets and dense bodies are more numerous.

Animals↗

The metabolism of supplementary vitamin C during the common cold.

Ascorbic acid concentrations have been measured in leukocytes and plasma following oral administration of 2000 mg vitamin C in the same subjects while they had cold symptoms and after recovery from their colds. Plasma and leukocyte concentrations rose significantly in females, but only plasma concentrations rose in males, after the loading dose during colds. In the postcold tests, only plasma concentrations rose in both sexes. There was a significant difference in plasma leukocyte regression coefficients between the cold and postcold tests in females. Ascorbic acid passes into the plasma for metabolic purposes, and its storage is less in the leukocytes, during colds. Males had worse colds than females because their catarrhal symptoms were more severe. Higher tissue concentrations of ascorbic acid tended to be associated with low total, toxic, and catarrhal symptom values. A rise in tissue ascorbic acid was associated with less severe catarrhal symptoms in females. Ascorbic acid concentrations in the plasma and tongue were significantly higher after the subjects had recovered from their cold symptoms. Increasing the loading dose of vitamin C from 500 to 2000 mg more than doubled the leukocyte concentration of ascorbic acid in females. The higher dose enabled uptake of the vitamin into the leukocytes to take place over a 4-hour period. It did not give rise to increased uptake into male leukocytes. Administration of supplementary vitamin C elevated plasma ascorbic acid. The ascorbic acid then passed into the tissues depleted of vitamin C during the cold syndrome. A single supplementary dose of 2000 mg vitamin C can replete leukocyte ascorbic acid during a 4-hour period in females, but a larger dose may be necessary in males.

Ascorbic Acid↗

Vitamin C metabolism and atopic allergy.

The procedure for carrying out the Leucocyte Ascorbic Acid Uptake Direct Antigen Challenge Test (LAADACT) is described. Leucocytes from normal individuals, when incubated in a buffered medium containing ascorbic acid, increase their ascorbic acid concentration by about 80%. When leucocytes from atopic individuals are incubated in a medium containing the antigen to which they are sensitive, as shown by positive skin tests, the leucocyte uptake of ascorbic acid is significantly reduced. Addition of antigen, to which atopic or normal individuals are not sensitive, to the incubation mixture does not reduce leucocyte ascorbic acid uptake. Measurement of ascorbic acid uptake into leucocytes is a relatively simple, routine, laboratory procedure. The LAADACT, therefore, provides a quick and accurate blood test for diagnosing sensitivity to specific antigens, and measuring relative antigenic sensitivities. The underlying mechanism of the LAADACT is discussed.

Antigen-Antibody Reactions↗