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Biomedical subjects

D Oda

Publications and source records attributed to D Oda.

60 records · Page 4Linked to original sources
PubMed1983

Achieving optimal immunization levels in school-age children.

In a school-based immunization program in four states, 70% of the students were fully immunized by the end of the first year and 85% by the end of the second year. Because of student turnover, 20% of the immunization levels achieved by the end of a school year were not sustained into the subsequent year. Levels reported by the state immunization officers were higher than those recorded by school personnel. Completed immunization series for students requiring immunizations were 33% to 40% higher for students enrolled at the start of the year than for students who entered during the school year. Students who were unimmunized at the beginning of the year had a better change (P less than 0.001) of being immunized by the end of the year than those whose immunization status was unknown. To maintain high levels, a program must be sustained and continuing, provide immunizations, and have careful administrative monitoring of child-specific population-based data. Schools are uniquely able to provide all of these elements, which can augment the efforts of private practitioners.

Child↗
PubMed1983

Comparative values of school physical examinations and mass screening tests.

In this study mass screenings identified more problems than did physical examinations, but more problems per 100 contacts were identified by physical examinations (51.6) than by screenings (4.7). When time necessary to accomplish the evaluation is considered, screenings are a more efficient way of identifying problems in the general diagnostic categories for which screenings can be provided, but most (85.8%) of the problems identified by physical examination were in categories for which screenings are not provided. Overall, 99.1% of the problems were identified without overlap between physical examinations and screenings. Eighty-three percent of the problems identified by physical examinations were previously unknown. By the end of the school year, 86.3% of the problems identified by physical examinations and 94.5% of those identified by screenings had been or were in the process of being resolved. The integration of physical examinations and screenings in a school setting, staffed by nurse practitioners supported by physicians, can maximize the identification and resolution of health problems.

Child↗
PubMedDate not supplied

Phosphatidylethanolamine deficiency in membrane lipids inhibits keratinocyte intercellular networks formation.

Ethanolamine (Etn) is required for the growth of epithelial cells in culture. Without Etn, the amount of phosphatidylethanolamine (PE) in membrane lipids is reduced, and cell proliferation stops. When the membrane lipids are deficient of PE, some extracellular signaling processes become impaired. In this study, we examined the effect of Etn deprivation on the formation of intercellular networks in immortalized human oral keratinocytes. Keratinocytes proliferate with undifferentiated morphologies in a low-calcium medium, whereas they undergo differentiation to form intercellular networks in a high-calcium medium. The cells were first cultured with or without Etn supplement in a low-calcium (0.07 mM) medium, and then the calcium concentration was raised to 1.8 mM. The localization and organization of the following proteins were examined: (1) desmogleins and plakoglobin in desmosomes, (2) E-cadherin and beta-catenin in adherens junctions and (3) actin and keratin filaments in cytoskeletons. As expected, in the Etn-supplemented cells, the elevated level of calcium induced the junctional localization of the proteins associated with desmosomes and adherens junctions and also induced the formation of keratin and actin networks. On the contrary, in the Etn-deprived cells, the elevated level of calcium induced none of the above processes. The results suggest that having a sufficient amount of PE or proper phospholipid composition in the membranes is crucial for differentiation in epithelial cells.

Actin Cytoskeleton↗
PubMedDate not supplied

Effect of vitamins A, C and E on normal and HPV-immortalized human oral epithelial cells in culture.

There is experimental and epidemiological evidence that antioxidant vitamins can inhibit carcinogenesis. Since immortalization by Human Papilloma Virus (HPV) is one possible early step towards carcinogenesis in oral epithelia, we studied the differential effect of vitamins A, C and E on HPV-immortalized oral epithelial cells (IHGK) as compared to the normal counterpart. The dose response was determined by morphology, cell cycle by flow cytometry, and growth curve by cell number. The optimum dose in terms of inhibitory effect vs. toxicity was determined for each vitamin by morphology. Optimum doses were: vitamin A--1.4 x 10(-5) M, vitamin C--10(-3) M, and vitamin E--10(-6) M for both HPV-immortalized and normal cells. Growth curve showed reduction of proliferation by all three vitamins, with vitamins A and E more effective than C for both cell types. Flow cytometry showed that vitamins A and E reduced the percentage of cells at G2 phase of cell cycle and indicated arrest in the S phase. This effect was greatest in the immortalized cells with a 50% and 35% decrease of G2 for vitamins A and E respectively, whereas the normal counterpart showed a 48% decrease for A and a 12% increase for E. By organotypic culture, the morphology was not markedly different between the vitamin-treated and the control cells, except for a slight increase in the keratinization of normal cells with vitamin A. Also noted was a reduction in number of cell layers from five layers or more for controls to only one or two for vitamin E. In conclusion, we have demonstrated that the antioxidant vitamins inhibit proliferation, and show a preferential effect on IHGK cells.

Ascorbic Acid↗
PubMedDate not supplied

H2O2 oxidative damage in cultured oral epithelial cells: the effect of short-term vitamin C exposure.

Smoking is the main etiology of oral cancer and generates oxygen free radicals in the oral cavity. Free radicals have been implicated in apoptosis and in DNA damage inducing alteration of the cell cycle. The antioxidant vitamin C (VC) is reported to inhibit damage induced by free radicals. We exposed cultures of normal human oral epithelial cells to hydrogen peroxide (H2O2) in the presence and absence of VC. Generation of hydroxyl radicals was measured by electron paramagnetic resonance (EPR), cell cycle alterations by flow cytometry, cell death by SYTO 11 and morphology by organotypic culture. Human primary cell culture was given four treatments - control, VC alone, H2O2 alone and VC followed by H2O2. Cell cycle analysis indicated cultures treated with H2O2 had fewer cells in G1 phase (26%) and higher number of cells in S phase (44%) compared to the control (G1 70% & S 14%). Cell cycle of 48 hour VC treatment followed by H2O2 was similar to H2O2 alone. SYTO 11 showed 22% cell death when treated with H2O2 alone compared to 9% of normal control. By organotypic culture H2O2 alone induced a two-fold cell proliferation, loss of maturation, nuclear hyperchromatism and nuclear crowding. Our results suggest that H2O2 is capable of altering the cell cycle and morphology of cultured normal human oral epithelial cells. Forty-eight hour exposure to Vitamin C does not prevent the cell cycle changes caused by hydroxyl radicals.

Ascorbic Acid↗