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Biomedical subjects

C T Huang

Publications and source records attributed to C T Huang.

At least 109 records · Page 6Linked to original sources

Protective effect of milk against in vitro caries.

Additions of milk solids to laboratory "cakes" made of sucrose and starch reduced in vitro (Orofax) "caries" and the dissolution of granular enamel, but increased the amounts of fermentation acids produced. Withdrawal of the milk component of ice cream, yogurt, and chocolate milk resulted in increased Orofax "caries".

Acids↗

Some observations on in vitro dental plaques.

A method is described for growing plaques in vitro in a flow of human saliva. Similarities between these in vitro plaques and natural in vivo plaques are seen in physical properties, bacterial composition, and pH response to sucrose solution.

Bacteria↗

Biochemical characterization of H2S-positive Salmonella sendai strains isolated in Hong Kong.

The biochemical properties of 8 H2S-positive variant strains of Salmonella sendai isolated from patients and carriers in Hong Kong were studied. Apart from the production of H2S, all these strains showed typical properties of S. sendai and a dependence on tryptophan. Their capacity to utilize different forms of sulphur sources varied, ranging from being capable of utilizing SO4, SO3, S2O3 and cystein to only cystein as the sulphur source.

Cysteine↗

Antibodies to germinating and yeast cells of Candida albicans in human and rabbit sera.

Two major antigenic components, I and II, were detected by double immunodiffusion in sonic extracts of the germinating (G) or yeast (Y) cells of the dimorphis organism, Candida albicans group A. Component I may be a heterogeneous mixture of antigens which are stable to heating and phenol. Component II is more homogeneous but is labile to heat and phenol. Rabbit antisera, showing only precipitin to component II or certain human sera at high dilution, were found to react with G cells to give an immunofluorescence which was confined to the germ tubes. This suggested that component II is localised on the germ tubes, whereas no immunofluorescent reaction against the yeast cells could be detected under the same conditions although component II was as readily extracted from these cells as from G cells. This suggested that component II might exist in a cryptic state in the Y cells. In support of the latter contention it was shown that live Y cells did not absorb precipitin to component II nor were they capable of providing these antibodies in rabbits. Using both human and rabbit sera, it was shown that the antigenic specificity of the immunofluorescence assay where Y cells were used was related to component I and that where G cells were used it was related to both components I and II.

Adolescent↗

Pulmonary sarcoidosis: roentgenographic, functional, and pathologic correlations.

Discrepancies were observed between functional (PFT), chest roentgenographic, and open lung biopsy findings (granulomata, interstitial pneumonitis, angiitis, and fibrosis) in 81 patients with clinical diagnosis of sarcoidosis. A combination of normal PFT and Type 1 roentgenographic findings (hilar lymphadenopathy) was associated with minimal lung lesions without fibrosis. Type 1 findings alone did not preclude extensive lesions or fibrosis. Advanced roentgenographic and PFT abnormalities correlated with the presence of extensive lung lesions. The pulmonary diffusing capacity correlated best with specific and overall lung pathology, and roentgenographic types. Only this test differentiated the extent of granulomata and the roentgenographic types. Moderate degrees of other pathologic changes were not distinguished by any other PFT. Degrees of overall lung pathology correlated with an individual PFT and most significantly with overall PFT (p less than 0.001). Serial studies of PFT are a practical and valuable means for assessment of the disease process in sarcoidosis.

Adolescent↗

Amputation: energy cost of ambulation.

A mobile instrument system was used to measure energy consumption by indirect calorimetry at rest and during ambulation in 25 unimpaired subjects, 6 unilateral below-knee (BK) amputee patients, 6 unilateral above-knee (AK) amputee patients and 4 bilateral AK amputee patients. To prevent the introduction of gait difficulties among the impaired subjects, each subject was permitted to walk at his own comfortable speed. Since speed thus varied among subjects, ambulation data were expressed in units of energy per foot traveled. Statistical analyses of the mean oxygen costs indicated several significant differences among the groups. In comparison to unimpaired subjects, the mean oxygen consumption was 9% higher in unilateral BK amputee patients, 49% higher in unilateral AK amputee patients and 280% higher in bilateral AK amputee patients.

Adult↗

Energy cost of ambulation in paraplegic patients using Craig-Scott braces.

Energy metabolism data were collected in a series of 8 male paraplegic patients with neurologically complete spinal cord lesions between T4 and T12 (1 patient had complete motor paralysis with incomplete sensory function). Energy costs were measured at the subject's seated basal rate (mean = 17.12cal/min/kg) and during 2 separate trials at ambulation using Craig-Scott braces. The rates of ambulation reflected the patient's perceived comfortable rate and ranged from 2.2 to 44.8m/min. (mean = 14m/min). The subjects ambulated in a straight line, with the data collection instrumentation (the Mobile Automatic Metabolic Analyzer) moving alongside. Mean O2 consumption was 0.1867ml/sec/kg and mean energy cost was 52.96 cal/min/kg, which when compared to a mean of 17.12 cal/min/kg at their resting state, represents a 3-fold increase in their energy cost. Three cases were further measured for O2 debt, which ranged from 1483 to 3112 ml and was repaid completely within 10 minutes post-walk.

Adolescent↗

Fiber, intestinal sterols, and colon cancer.

It has been postulated that dietary fiber's protective effect against the development of colon cancer, diverticular disease, and atherosclerosis may be due to the adsorption and/or dilution of intestinal sterols such as bile acids and neural sterols and their bacterial metabolites by component(s) of fiber. Dietary fiber is made up of four major components-cellulose, hemicellulose, lignin, and pectin. There is evidence that hemicellulose and pectin may induce an increase in fecal bile acid excretion in man which may be accompanied by a decrease in serum cholesterol. Natural fibers, such as rolled oats, alfalfa, guar gum, and Bengal gram have been shown to have hypocholesterolemic properties of alfalfa, wheat straw, and some other fibers found considerable amounts of bile acids in vitro. On the other hand, wheat bran, oat hulls, and all the synthetic fibers tested bound only negligible amounts of bile acids under the same conditions. Vegetarians in the United States have lower plasma lipids and different plasma lipoprotein patterns than those of comparable control populations on regular mixed diet. They also have smaller daily fractional turnover rates of cholic acid and deoxycholic acid pool size. In addition, populations on a mixed Western diet, where the rate of large bowel cancer is high (North American, English, Scottish, etc.) degraded and excreted cholesterol and bile acid metabolites to a greater degree than populations where the rate of colon cancer is comparatively low (Ugandan, Japanese, etc). It cannot be denied that the fiber theory linking fiber deficiency with the development of colon cancer and other diseases, is simple, attractive and appears to be firmly based in common sense. When subjected to research studies, however, the situation appears much more complex than expected. Although some progress is being made, the data are often contradictory and confusing, probably due to lack of adequate documentation of fiber intake (e.g., use of dietary fiber instead of crude fiber) and/or the absence of detailed information on the chemistry of the fiber itself.

Adult↗

Salmonella in pig carcasses for human consumption in Hong Kong: a study on the mode of contamination.

A very high proportion (75%) of the pigs slaughtered in Hong Kong were found to be infected with salmonellas. Seven serotypes including Salmonella choleraesuis were isolated but the majority (91%) were S. anatum and S. derby. These serotypes, especially S. anatum and S. derby, had been isolated frequently from clinical cases, symptomless carries and in this study from abattoir workers, suggesting that the pig was a significant source for human salmonella infection. The majority of pigs slaughtered are imported and the high level of apparent infection was thought to be due to cross-infection during transport of the pigs under stress. S. anatum and S. derby were also isolated from pigs at 60 degreesC for 5 min caused no great reduction in the degree of superficial contamination. The two predominant serotypes were isolated from the tank and from drain swabs, and also from the latter held under scalding tank conditions. Thus, in spite of the introduction of hygienic slaughter under modernized conditions employing an automatic conveyance system 55% of the carcases were superficially contaminated after dressing before despatch to customers. Control of infection before slaughtering would appear crucial and a more thorough rinsing or washing of the dressed carcasses desirable.

Abattoirs↗

Granulomatous pulmonary angiitis in sarcoidosis.

The occurrence and morphologic aspects of granulomatous pulmonary angiitis were evaluated in open lung biopsy specimens from 128 patients with sarcoidosis. All of the specimens showed parenchymal granulomas characteristic of sarcoidosis, and in 88(69%), granulomatous angiitis was seen. In the speclimens that exhibited granulomatous angiitis, venous involvement was mos common, seen in 92% of the cases. In 61% of these biopsy specimens, only venous involvement was seen; in 31%, both venous and arterial involvement was present. Only 8% of the positive specimens showed arterial lesions exclusively. The extent of angiitis was quantitated. Focal segmental elastic tissue destruction, partial or complete, was a common finding. No instances of aneurysm formation, endothelial erosion, or thrombosis were observed. Occlusive narrowing of small vessels was frequent. Bronchial blood vessels were not involved.

Adolescent↗