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Biomedical subjects

K Han

Publications and source records attributed to K Han.

At least 145 records · Page 8Linked to original sources
PubMed1986

Age differences in phagocytosis by polymorphonuclear leukocytes measured by flow cytometry.

Elderly persons have increased morbidity and mortality due to bacterial infections. Since the polymorphonuclear leukocyte (PMN) is a major defense against bacterial infection, we utilized fluorescent microspheres and flow cytometry to examine phagocytosis by PMNs from 55 young and middle-aged adults (mean age 41.5 yrs) and two groups of elderly subjects: one group of 35 healthy individuals (mean age 74.1 years) living at home, and a second group of 11 residents (mean age 83.1 years) with severe mental and physical disabilities, living in a domiciliary care facility. We determined the percent phagocytic PMNs, the number of microspheres per PMN, and the number of microspheres per 100 PMNs. The mean number of microspheres per phagocytic PMN was similar for all groups. Statistically significant differences were found between the young and middle-aged group and the healthy or ill elderly groups for the percent phagocytic PMNs (75.3% vs 51.5% and 43.8%), and the number of microspheres per 100 phagocytic PMNs (197.3 vs 131.4 and 103.2). There were no significant differences in these parameters between healthy and debilitated elderly subjects. These data document that there is an age-related increase in representation of a population of PMNs which have a defect in phagocytic ability.

Adult↗
PubMed1985

The development of mechanical strength of surgically anastomosed arteries sutured with Dexon.

The strength of surgically anastomosed arteries of the rat sutured with Dexon thread is studied. The abdominal aortas and the carotid arteries were severed, sutured and then the wounds were closed and the animal healed. After a specific period of time up to 13 months, the vessels were taken out and tested in uniaxial loading condition. The stress-strain relationship of the vessels was measured, and then the vessels were pulled to failure. It was found that the strength of the anastomosis was the lowest in about 4 months. In the first day, the force at failure was about the same as that of the control. Then the strength decreased with time, until a minimum was reached in 4-6 months. The tensile force to failure was about 25% of the control for the carotid artery and 49% of the control for the abdominal aorta. The corresponding values of the tensile stress at failure were 17 and 11%, respectively. The different percentages of forces and stresses were caused by the thickening of the vessel wall in the neighborhood of the suture line in the healing process. After 4-6 months, the strength gained again. At 13 months, the strength of the anastomosis was about the same as that of the control. The stretch ratio at failure was approximately constant through all periods.

Animals↗
PubMed1984

NMR study of the exchange rates of allosterically responsive labile protons in the heme pockets of hemoglobin A.

1H NMR spectroscopy has been used to measure the proximal histidyl labile ring proton (NH) rates of exchange with bulk solvent in the individual subunits of hemoglobin (Hb) A. These protons displayed a substantial decrease in their exchange rates in comparison with related monomeric proteins and exhibited sensitivity to the quarternary state. With the beta subunit NH, the exchange behaviour was similar to an allosterically responsive subset of protons, which have been identified using 1H-3H methods (Englander, J.J., R. Rogero, and S. W. Englander, 1983, J. Mol. Biol. 169:325-344). Assuming similar exchange mechanisms for the two subunits, the NMR data suggested a more flexible alpha than beta subunit in Hb A.

Heme↗
PubMed1983

Efficacy of polyglycolic acid (Dexon) microsutures in peripheral nerve anastomoses in the rat: 1. Epineural suture.

The efficacy of polyglycolic acid (Dexon) microsuture in peripheral nerve repair was studied using 84 and 28 reanastomoses of freshly severed rat sciatic nerve employing Dexon and nylon 9-0 interrupted epineural suture technique. Animals were sacrificed and sutured portions of the nerves were histologically examined. There were almost identical suture reactions by day 7, except that the intensity of polymorphonuclear (PMN) and macrophage infiltrate in the nylon-sutured nerves was far greater than in the Dexon-sutured group. Although the intensity of the nylon-suture reaction subsided considerably after day 21, the lymphocytes, macrophages, and plasma cells surrounded the suture as long as the sutures remained in the nerves up to 12 months postoperatively. The Dexon-sutured nerve segments showed disappearance of the inflammatory cells as soon as the sutures were completely absorbed. The Dexon sutures were still detectable at months 1 and 2 but not after month 3.

Animals↗
PubMed1983

An open study of ceftazidime in the treatment of serious bacterial infection.

Ceftazidime, a new parenteral cephalosporin, was given by intravenous bolus injection to 50 patients admitted to hospital with a variety of serious infections. These included septicaemia, bronchopulmonary, urinary, gastro-intestinal and soft tissue infections. The drug proved to be effective against a wide range of organisms, notably opportunistic Pseudomonas aeruginosa infections. In the 32 patients with positive cultures there was a cure rate of 85%. All Ps. aeruginosa infections were eradicated, but two relapsed post treatment in patients with recurrent urinary infections related to indwelling catheters. The drug was well tolerated and no serious side effects occurred. Two patients with salmonella septicaemia relapsed after an initial clinical response, and one of these died.

Adolescent↗
PubMed1982

Vasovasostomy in the rat. Improved technique using absorbable microsuture (polyglycolic acid).

An improved technique for vasovasostomy in the rat is presented. To eliminate the suture crowds that could cause obstruction of the vasal lumen, one deep raw suture technique had been employed using polyglycolic acid (Dexon) microsuture. A total of 62 vasal anastomoses in 48 male Lewis rats was performed, and follow-up to twelve months found no disruption or constriction at the anastomoses. Despite occasional sperm granuloma formation at the anastomotic sites, all anastomoses demonstrated patency. Dexon appears to be suitable for genitourinary tract surgery, at least, in the rat.

Animals↗
PubMed1981

Accessibility of epsilon-amino groups of lysine to guanidination in kappa-elastin from bovine ligamentum nuchae.

Kappa-Elastin contains 3.81 lysyl residues per 1000 residues of amino acids. Among these residues, free epsilon-amino groups represent about 16 p. 100, as revealed by guanidination, the buried lysyl residues (buried epsilon-amino groups) represent about 33 p. 100, as revealed by dansylation. After drastic reduction by borohydride, no aldimine bonds were detected and only 6 p. 100 of "deeply buried" amino groups of lysyl residues were detected by a second dansylation. The remaining lysines (about 46 p. 100) are engaged or inaccessible.

Animals↗
PubMed1979

Guanidination of kappa-elastin from bovine ligamentum nuchae.

Kappa-Elastin is exhaustively guanidinated in order to chemically modify the pre-existing lysine content to homoarginine. However the pre-existing lysine content is only modified to homoarginine content about 50 p.cent. The other lysyl-bonds are buried or/and engaged to aldi-imine bonds or other bonds. Therefore the first guanidinated kappa-Elastin is submitted to partial acide hydrolysis (HCL, 1 N, 110 degrees C for 2 hours) and submitted to a second exhaustive guanidination. The pre-existing lysin content in kappa-Elastin almost quantitively disappeared and is transformed to the corresponding homoarginine. These results are similar to those obtained by photolysis of (Iso) desmosine residues by UV light which will liberate "new" lysine containing peptides from kappa-Elastin.

Amino Acids↗
PubMed1976

Comparison of the amino acid sequence of pig heart myoglobin with other ungulate myoglobins.

The primary structure of pig heart myoglobin has been established by study of the tryptic peptides of whole globin and by analysis of the fragments obtained by CNBr cleavage. Thermolysin and chymotrypsin digestion were used to determine the sequence of the M fragment (56-131). Automatic Edman degradation of whole globin and of the M fragment completed the sequence of pig myoglobin. Comparison with other ungulates shows that pig myoglobin is far from other artiodactyls previously studied (ox and sheep) and close to the eutherian ancestral chain.

Amino Acid Sequence↗
PubMed1976

The covalent structure of dog myoglobin.

The primary structure of the myoglobin of the domestic dog (German shepherd) was studied. Tryptic and thermolytic peptides were compared with the sequence of other known myoglobins; the stepwise automatic Edman's degradation of the whole globin and also the chymotryptic digestion of the median fragment obtained by CNBr cleavage completed this sequence. Comparison of the established dog myoglobin structure with those from other carnivora shows 16 differences versus badger, 20 versus harbour seal and 15 versus California sea lion.

Amino Acid Sequence↗