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Biomedical subjects

H Yang

Publications and source records attributed to H Yang.

At least 1,027 records · Page 57Linked to original sources
PubMed1983

Nonspecific cytotoxicity of vaccinia-induced peritoneal exudates in hamsters is mediated by Thy-1.2 homologue-positive cells distinct from NK cells and macrophages.

Vaccinia virus-induced peritoneal exudate cells (PEC) in the hamster were characterized with regard to cell type(s), target specificity, and expression of the T cell antigen, Thy 1.2 homologue. Hamsters were immunized intraperitoneally with vaccinia virus and cytotoxicity was measured against 51Cr-labeled targets in a 16-hr assay. PEC collected 4 days after immunization were cytotoxic for both baby hamster kidney cells (BHK) and herpes virus-infected BHK (BHKHSV). Both the nonadherent (lymphocyte) and adherent macrophage (MP) fractions of PEC were cytotoxic. Treatment of cells with a monoclonal anti-murine Thy 1.2 antibody (alpha-Thy 1.2) known to detect a Thy 1.2 homologue on hamster T cells, removed all of the cytotoxicity in both PEC fractions, whereas, cytotoxic spleen cells from the same animals were resistant to antibody treatment. Similarly, the cytotoxic cells in PEC induced by bacillus Calmette-Guérin were exclusively of the Thy 1.2 homologue-positive phenotype. Target specificities of Thy 1.2+ PEC and Thy 1.2- spleen cells were similar as evidenced by comparable activity against hamster BHK and BHKHSV targets and murine SV3T3 and YAC-1 targets. Previous studies have attributed the cytotoxicity of the adherent PEC to MP. However, as determined by immunofluorescence and morphological studies, treatments that enriched for MP decreased cytotoxic activity, whereas, procedures that enriched for lymphocytes enhanced cytotoxic activity suggesting that all cytotoxicity in PEC is mediated by a non-specific Thy 1.2 homologue positive lymphocyte (Thy 1.2+ CL). Thus our data support the conclusion that intraperitoneal inoculation of hamsters with vaccinia induces two distinctly compartmentalized phenotypes with similar cytotoxic characteristics--the Thy 1.2+ CL and the Thy 1.2 homologue-negative natural killer cell (NK) or NK-like cell in the peritoneum and in the spleen, respectively.

Animals↗
PubMed1981

[Continuously do a good job in planned parenthood work and fulfill this year's population target].

It has been a year since the CCP Central Committee issued an open letter to all CCP and CYL members on population control. In the past year, CCP and CYL members and the broad masses of people in our province have actively responded to the CCP Central Committee's call--1 child/couple. Over 1.7 million couples of childbearing age have applied for only-child certificates. Our province has scored great achievements in planned parenthood work. However, we must realize that new situations and new questions have arisen in planned parenthood work. 1st, the peak period of population growth in our province is from the late 1950s to the 1960s. Children born in this period are now entering the childbearing age. There soon will be a new peak population growth period. 2nd, because of the enactment of the new marriage law, the number of those married in the first 1/2 of this year doubled that of previous years. Responsibility systems in rural areas have pomoted development of productive forces. This is very good, but this has also stimulated population growth because people mistakenly think that more children mean more labor forces and more income. They begin to think of having more chidlren--especially sons. Some localities have lost control of population growth. The birth rate in rural areas has begun to climb quickly. If no measures are adopted immediately, our province's population will swell enormously. All the achievements scored in the 1970s will probably be spoiled, and we likely will again commit a historical error. As far as our province is concerned, planned parenthood is imperative. In 1949, our province's per capita farmland was 3 mu. At the end of 1980, it was only 1.49 mu. If no measures are adopted and the population keeps growing, the consequences will be serious.

Asia↗
PubMed1970

Effects of N2-O2 and CO2-O2 tensions on growth of fungi isolated from damaged flue-cured tobacco.

Ten fungi, Aspergillus niger, A. flavus, A. ochraceus, A. ruber, A. repens, A. amstelodami, Alternaria tenuis, Penicillium brevi-compactum, Cladosporium herbarum, and Chaetomium dolicotrichum, were isolated from moldy flue-cured tobacco and grown in various mixtures of N(2)-O(2) or CO(2)-O(2). A 1 to 5% concentration of O(2) in an N(2) atmosphere caused the greatest change in growth of the nine species, and a 10 to 20% concentration of O(2) for A. flavus. All species, except A. amstelodami and A. ruber, grew faster in air than in mixtures containing 10% O(2). High O(2) concentrations generally inhibited furrow production in the mycelial mats. In an atmosphere of 5 to 40% O(2) in the N(2) atmosphere, furrows formed in mycelial mats between 5 and 40% O(2) in the species except for A. ruber, A. repens, and A. amstelodami, which produced none in any concentration. As O(2) decreased below 20%, spore production was progressively decreased, colony color faded to white, and cleistothecia formation was suppressed. In CO(2)-O(2) mixtures radial growth of all species increased with each quantitative decrease of CO(2). All species except A. niger grew faster in air than in 10% CO(2). In contrast to N(2)-O(2) mixtures, the fungi formed furrows, sporulation and cleistothecial formation were suppressed, and colony color changed to white in higher O(2) concentrations.

Ascomycota↗
PubMed1968

Fungi isolated from tobacco leaves and brown-spot lesions before and after flue-curing.

Discs of tissue excised from ripe nonflue-cured and flue-cured tobacco leaves, harvested on six dates and cultured on three selective media, yielded 21 and 24 genera of fungi, respectively. Of 5,094 fungi isolated from 3,240 pieces of nonfluecured leaf tissue, 89.5% comprised five genera, Alternaria, Cladosporium, Epicoccum, Trichoderma, and Nigrospora. Of 2,494 fungi isolated from 3,240 pieces of flue-cured leaf tissue, 70.9% were Alternaria, Cladosporium Epicoccum, Aspergillus, and Nigrospora. Flue-cured and nonflue-cured brown-spot lesions harvested at two locations yielded 12 and 14 genera of fungi, respectively. Alternaria, Penicillium, Phoma, and Stemphyllium comprised 91.5% of the 2,245 fungi isolated from noncured and 87.1% of the 1,118 fungi isolated from the cured lesions. The number and kinds of fungi obtained from diseased and healthy tissue were reduced but not eliminated by flue-curing.

Journal Article↗
PubMedDate not supplied

Health information on the Internet: accessibility, quality, and readability in English and Spanish.

CONTEXT: Despite the substantial amount of health-related information available on the Internet, little is known about the accessibility, quality, and reading grade level of that health information. OBJECTIVE: To evaluate health information on breast cancer, depression, obesity, and childhood asthma available through English- and Spanish-language search engines and Web sites. DESIGN AND SETTING: Three unique studies were performed from July 2000 through December 2000. Accessibility of 14 search engines was assessed using a structured search experiment. Quality of 25 health Web sites and content provided by 1 search engine was evaluated by 34 physicians using structured implicit review (interrater reliability >0.90). The reading grade level of text selected for structured implicit review was established using the Fry Readability Graph method. MAIN OUTCOME MEASURES: For the accessibility study, proportion of links leading to relevant content; for quality, coverage and accuracy of key clinical elements; and grade level reading formulas. RESULTS: Less than one quarter of the search engine's first pages of links led to relevant content (20% of English and 12% of Spanish). On average, 45% of the clinical elements on English- and 22% on Spanish-language Web sites were more than minimally covered and completely accurate and 24% of the clinical elements on English- and 53% on Spanish-language Web sites were not covered at all. All English and 86% of Spanish Web sites required high school level or greater reading ability. CONCLUSION: Accessing health information using search engines and simple search terms is not efficient. Coverage of key information on English- and Spanish-language Web sites is poor and inconsistent, although the accuracy of the information provided is generally good. High reading levels are required to comprehend Web-based health information.

Consumer Advocacy↗
PubMedDate not supplied

Serum suppresses myeloid progenitor apoptosis by regulating iron homeostasis.

The growth and survival of committed hematopoietic progenitors is dependent upon cytokine signaling. However, serum is also required for optimal growth of these progenitors in culture ex vivo. Here we report that serum withdrawal leads to myeloid progenitor cell apoptosis. Although serum deprivation-induced cell death has many hallmarks typical of apoptosis, these cell deaths were not inhibited by hemopoietins, survival factors such as IGF-I, or treatment with a broad-spectrum caspase inhibitor. Rather, apoptosis due to serum withdrawal was associated with damage to mitochondria. Surprisingly the serum factor required for myeloid cell survival was identified as iron, and loss of iron led to marked reductions in ATP production. Furthermore, supplementing serum-deprived myeloid cells with bound or free iron promoted cell survival and prevented mitochondrial damage. Therefore, serum suppresses hematopoietic cell apoptosis by providing an obligate source of iron and iron homeostasis is critical for proper myeloid cell metabolism and survival.

Adenosine Triphosphate↗