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Biomedical subjects

P P Yang

Publications and source records attributed to P P Yang.

6 recordsLinked to original sources
PubMed1997

Personal flotation device usage: do educational efforts have an impact?

Boating is a popular form of recreation in the United States. Unfortunately, many people drown due to boating-related accidents each year. Since many such drowning deaths are preventable through the use of personal flotation devices (PFDs), an observational study was conducted to quantify and evaluate the number and demographics of the individuals who choose to wear life jackets in King County, Washington. Further efforts were then directed toward evaluating the effectiveness of educational campaigns focused on increasing PFD usage and general boating safety. Highly significant increases were found in the use of life preservers overall and within various subgroups of the population. Total PFD use increased from 19.8% in 1992 to 31.3% in 1994. Future studies are needed to determine the reproducibility of this data and the feasibility of incorporating similar educational efforts into other injury prevention programs nationwide.

Adolescent↗
PubMed1992

Literature survey on biomedical applications of thermography.

Thermography is a noninvasive technique through which temperatures are monitored and recorded, thereby allowing visualization of heat flow. There are three types of thermography: liquid crystal thermography (LCT), infrared thermography (IRT) and microwave thermography (MWT). This paper presents a survey of the literature pertinent to the biomedical applications of these types of thermography. The noninvasive and high resolution characteristics of the thermographic systems make them valuable diagnostic as well as therapeutic aids. Typical research areas include detection of blood flow, diagnosis of joint inflammation and cancer, thermal modeling of various body parts, and use in reproductive problems. The survey discloses that thermography has found applications in various fields in medicine, veterinary medicine, pharmacy, and dentistry.

Cardiovascular Diseases↗
PubMed1984

Modulation of cell-associated plasminogen activator activity by cocultivation of a stem cell and its tumorigenic descendant.

The effect of the presence of one cell type on the plasminogen activator activity of another cell type was studied. The cell types, AC and D, were isolated from a rat neuroblastoma (I. Imada and N. Sueoka, Dev. Biol. 66:97-108, 1978). AC cells are stem cells capable of multipotential differentiation in vitro and have little or no cell-associated plasminogen activator activity. D cells are tumorigenic and have high levels of cell-associated plasminogen activator activity. When AC cells were cocultivated with D cells, the plasminogen activator activity of the D cells was dramatically inhibited. The presence of as few as 1,250 AC cells inhibited 70% of the plasminogen activator activity of 20,000 D cells, as determined by a highly quantitative assay. The amount of inhibition by AC cells was proportional to the number of AC cells present. At increasing numbers of AC cells and a constant number of D cells, the Vmax for the activation of plasminogen proportionately decreased and the Km remained constant, implying that AC cells did not alter the structure or concentration of plasminogen. Inhibition was not mediated by a soluble inhibitor secreted by AC cells. Rather, attachment of AC cells adjacent to D cells, i.e., cell-to-cell contact, seemed to be required for inhibition. The substratum-attached material of AC cells, that which remained on the microwell surface after removal of AC cells with EDTA, inhibited D cell plasminogen activator activity. If plasminogen activator activity is involved in metastasis, then regulation of the plasminogen activator activity of one cell type by another cell type may be involved in determining which cells in a tumor can metastasize and where secondary tumors can arise.

Animals↗
PubMed1980

Cadmium-113 nuclear magnetic resonance investigation of metal binding sites in concanavalin A.

Cadmium-113 nuclear magnetic resonance studies are presented on the 113Cd-substituted protein concanavalin A (Con A). This protein has two different conformations, locked and unlocked, as described previously by Brown et al. [Brown, R. D., III, Brewer, C. F., & Koenig, S. H. (1977) Biochemistry 16, 3883]. The unlocked form of Con A gives one 113Cd resonance, indicating rapid exchange of the metal ions between the solution and the binding sites. Solutions of the locked form show three resonances: a free cadmium resonance (68 ppm), a resonance assigned to 113 Cd occupying the manganese site (46 ppm), and a resonance assigned to 113Cd occupying the calcium site (--125 ppm). In addition, Pb(II) is shown to bind to the calcium site and Zn(II) is shown to have high affinity for both sites. Data have been presented in previous literature that support a model in which Con A binds monosaccharides in a different manner than it binds oligosaccharides. However, if this difference exists, it does not affect the metal binding sites. Also, some heterogeneity in Con A has been reported in the literature; however, we have shown that the presence of these heterogeneities does not affect the 113 Cd NMR parameters.

Binding Sites↗