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Biomedical subjects

Y Hahn

Publications and source records attributed to Y Hahn.

65 records · Page 4Linked to original sources
PubMed1984

Childhood injuries caused by nonpowder firearms.

Motivated by four penetrating brain injuries to children caused by BBs, a study was undertaken to (1) assess the danger posed by nonpowder guns and rifles and (2) evaluate current regulations pertaining to these products. Data from the US Consumer Product Safety Commission indicate that there are many nonpowder firearm injuries, predominantly among males aged 5 to 24 years. Nonpowder firearm injuries are close in prevalence to those caused by powder firearms and include fatalities. More than one fourth of reported nonfatal injuries are to the eye, face, head, or neck. Despite the hazard they pose, nonpowder firearms are regulated loosely, such that young teens can legally purchase and use the products in most jurisdictions. We propose stricter regulations and other means to prevent serious and fatal nonpowder firearm injuries.

Adolescent↗
PubMed1982

Structural identity of human histocompatibility leukocyte antigen-B27 molecules from patients with ankylosing spondylitis and normal individuals.

Although the association between human histocompatibility leukocyte antigen (HLA) B27 and ankylosing spondylitis is the prototype of HLA-disease association, the mechanism underlying these associations has not been determined. We have investigated the possibility that the B27 molecules from patients with ankylosing spondylitis are different from those of normals, and only the "different" molecules predispose the individual to disease. Biosynthetically radiolabeled HLA-B27 molecules from patients with ankylosing spondylitis and normal individuals were compared by two-dimensional gel electrophoresis and tryptic peptide mapping with high pressure liquid chromatography. Extensive charge heterogeneity in the 45,000-dalton heavy chain was detected when B27 molecules were analyzed by two-dimensional gel electrophoresis; the charge heterogeneity was reduced, but not eliminated, when the B27 molecules were treated with neuraminidase to remove sialic acid residues before analysis. No structural difference in the B27 molecules from an ankylosing spondylitis patient and a normal individual were detected by two-dimensional gel electrophoresis. Analysis of [(3)H]leucine-labeled and [(3)H]arginine-labeled tryptic peptides and chymotryptic peptides of the trypsin insoluble material by reverse-phase high pressure liquid chromatography revealed identity of the B27 molecules from ankylosing spondylitis patients and normal individuals. These studies indicate that development of akylosing spondylitis in only some B27 positive individuals is not attributable to those individuals possessing variant B27 molecules.

Arginine↗
PubMed1980

Partial N-terminal amino acid sequences of guinea pig classic histocompatibility antigens.

Partial N-terminal amino acid sequences were determined by microsequencing for three of the guinea pig GPLA-B classic histocompatibility antigens, which are presumably allelic products. The sequences of GPLA-B.1 derived from the noncongenic inbred strain 2 and strain 13 animals showed no differences a their N-termini, suggesting that these molecules are chemically as well as serologically identical. Two residues, isoleucine and leucine, were found at position 5 of the sequence of GPLA-B.1, suggesting that GPLA-S, the product of the second classic histocompatibility locus, was being cosequenced. GPLA-B.2 and GPLA-B.3 antigens showed distinct sequence differences from GPLA-B.1 and from each other. The sequences of GPLA-B.3 derived from a random-bred guinea pig and from the inbred DHCBA strain showed no differences and showed a possible species specific residue. All sequences showed significant homology with histocompatibility antigens of other species, suggesting a common evolutionary origin.

Amino Acid Sequence↗
PubMed1977

The mutual clonal origin of the lymphoplasmocytic and lymphoma cell in alpha-heavy chain disease.

Biosynthetic studies in alpha-heavy chain disease were performed on the gut tumour which was composed mainly of lymphoplasmocytic cells and on the mesenteric lymph node tumour composed mainly of immunoblasts. The gut tumour cells synthesised alpha-heavy chains and secreted them during 2-5 hr culture, whereas the lymph node tumour cells synthesized alpha-heavy chains which were shed into the culture medium only after 20 hr. These chains were shown to be present on the surface of the immunoblastic tumour cells by enzymatic radioiodination. Both the surface and the secreted alpha-heavy chain of the lymph node and gut tumour were found to be smaller than the alpha-heavy chain of myeloma proteins. These results suggest that the lymphoblasmocytic and the immunoblastic tumour cells originate from the same defective clone.

Adult↗
PubMed1973

Cell-surface immunoglobulin human thymus cells and its biosynthesis in vitro.

Human thymus cells synthesize immunoglobulin in short-term culture, the nascent immunoglobulin appearing in both cytoplasmic and membrane fractions. Surface immunoglobulin was demonstrated by lactoperoxidase radioiodination of the cells. The demonstration of intracellular and surface immunoglobulin required procedures that minimize proteolytic degradation. Noncovalently linked, monomeric mu chains and light chains were found in the cytoplasm and on the surface of the cells by means of acrylamide gel electrophoresis and by specific immunoprecipitation of the isolated chains.

Animals↗