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Biomedical subjects

K W Kang

Publications and source records attributed to K W Kang.

At least 55 records · Page 3Linked to original sources
PubMed1996

A cysteine-rich serine protease inhibitor (Guamerin II) from the non-blood sucking leech Whitmania edentula: biochemical characterization and amino acid sequence analysis.

A cysteine-rich serine protease inhibitor (Guamerin II) was isolated from the non-blood sucking leech Whitmania edentula. The new inhibitor was identified as a low molecular weight (6,012 Da) polypeptide with some sequence similarities to antistasin, hirustasin and guamerin. The inhibitor contained 56 amino acid residues with 76.8% sequence similarity to guamerin, 48.2% to hirustasin and 28.6% to the first domain of antistasin. This new inhibitor was the first completely sequenced serine protease inhibitor from a non-blood sucking leech. Analysis of the inhibitor revealed that it was active against neutrophil elastase and chymotrypsin, but had no activity against a variety of other proteases. The P1 reactive site residue was identified as methionine and the residues surrounding the P1 site were hydrophobic amino acids. The primary structure of the inhibitor showed no similarity to well-known elastase inhibitors from leeches such as eglin.

Amino Acid Sequence↗
PubMed1995

Isolation and characterization of guamerin, a new human leukocyte elastase inhibitor from Hirudo nipponia.

A new human leukocyte elastase inhibitor was extracted and purified from a Korean native leech Hirudo nipponia. The inhibitor, called guamerin, has a molecular weight of 6,110 and shows inhibition constant (Ki) of 8.1 x 10(-14) M. It is stable at a wide range of pH from 1 to 11 and heat-stable up to 90 degrees C. The complete amino acid sequence of guamerin reveals a cysteine-rich polypeptide of 57 amino acid residues that shows no similarity to any known elastase inhibitors but has 51% sequence homology with hirustasin. Guamerin has identical spacing of 10 cysteine residues as antistasin-type serine proteinase inhibitors, but the P1 reactive site residue is Met36 instead of Arg. The neighboring sequence of the reactive site consists primarily of hydrophobic amino acid residues. Based on examinations of the target proteinases and the reactive site specificity, guamerin is a new low molecular weight protein that inhibits elastases.

Amino Acid Sequence↗
PubMed1995

In vitro inhibition of gap junctional intercellular communication by chemical carcinogens.

This study was conducted to assess the effects of chemical carcinogens on the gap junction-mediated intercellular communication in cultured mammalian cells. The method of scrape-loading dye transfer of lucifer yellow was adapted as a measure of gap junctional communication. Clone 9 cells derived from rat liver were treated with a model chemical carcinogen, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and the gap junctional communication was assessed by measuring the transfer of scrape-loaded lucifer yellow dye. When cells were treated with the carcinogen at 0.3 mg/ml, the fluorescent dye transfer was inhibited by 90% in 60 min. Other chemical agents, which include direct or indirect carcinogens and antitumor drugs, were also examined for their effects on the gap junctional communication. Direct carcinogens, such as MNNG, hydroxylamine and ethidium bromide, exhibited strong inhibition of intercellular communication, while indirect carcinogens, such as aflatoxin B1 and ethionine, exerted minor effects. Effects of test chemicals on the cell communication through gap junctions were readily quantitated by counting the number of cells stained with the fluorescent dye.

Animals↗
PubMed1992

The medical treatment of a tuberculous tracheo-oesophageal fistula.

Tracheo-oesophageal (TE) fistulas caused by Mycobacterium tuberculosis are rare and usually require both surgical treatment and medical treatment with antituberculosis drugs. A patient with a tuberculous TE fistula and mediastinal lymphadenitis was successfully treated by medical management alone.

Adult↗
PubMed1992

Relationship between activities of cytochrome P-450 monooxygenases in human placental microsomes and binding of benzo(a)pyrene metabolites to calf thymus DNA.

Benzo(a)pyrene metabolism in human placental microsomes from smokers was studied. Benzo(a)pyrene metabolites were separated using high pressure liquid chromatographic technique. Reaction of benzo(a)pyrene with a microsomal fraction of placenta from individuals who smoke cigarettes during pregnancy yields 7,8 dihydroxy benzo(a)pyrene as a major metabolite, while 3'-hydroxy benzo(a)pyrene, 4,5 dihydroxy benzo(a)pyrene and quinones constitute minor metabolites. The activities of arylhydrocarbon hydroxylase and 7-ethoxycoumarin deethylase exhibited much higher activities in smokers than in nonsmokers. Examination of specific binding of monoclonal antibodies to cytochrome P-450 isozymes in placental microsomes revealed that cigarette smoking specifically enhanced the level of cytochrome P-450 c and d isozymes in human placental microsomes. Coincubation of 3H-benzo(a)pyrene and calf thymus DNA with placental microsomes yielded acid insoluble 3H-B(a)P from smokers, suggesting that cigarette smoking may induce placental enzymes which convert benzo(a)pyrene into ultimate metabolites to form carcinogen-DNA adducts.

Animals↗
PubMed1991

Inhibition of mutagenesis and transformation by root extracts of Panax ginseng in vitro.

The root extract of Panax ginseng was investigated for its inhibitory effects on DNA synthesis, mutagenicity, and cellular transformation using V79 and NIH 3T3 cells. DNA synthesis measured by the [3H]thymidine incorporation into V79 Chinese hamster lung cells was significantly decreased by the addition of ginseng extract (0-1 microgram/ml) to the medium. However, ginseng extract was found to increase the rate of DNA excision repair synthesis in V79 cells in response to treatment with UV radiation or methyl methanesulfonate. The extract also showed decreased mutation frequency when mutagenicity was examined using V79 cells at the hypoxanthine-guanine phosphoribosyl transferase locus as resistance to 6-thioguanine after exposure to methyl methanesulfonate. We also found that the components of ginseng extract continue to exert an inhibitory effect on the transformation of NIH 3T3 cells initiated by 3-methylchloanthrene, methyl methanesulfonate, and 1-methyl-3-nitro-1-nitrosoguanidine.

Animals↗
PubMed1990

Inhibition of DNA excision by DNA polymerase-alpha inhibitor in UV-damaged HeLa cells.

HeLa cells treated with 10 J/m2 of ultraviolet (UV) radiation were examined for inhibition of DNA excision by inhibitors of DNA polymerase-alpha and -beta. DNA repair synthesis and excision were inhibited by aphidicolin, a specific inhibitor of DNA polymerase-alpha. Decreased release of radioactive nucleotides from UV-damaged DNA by the inhibitor indicates that the action of DNA polymerase-alpha activity is closely associated with DNA excision. Dideoxythymidine also inhibited DNA repair synthesis but failed to block the excision, suggesting that polymerization by DNA polymerase-beta might precede removal of damaged DNA.

Antibiotics, Antineoplastic↗
PubMed1985

TWINAN: twin data analysis program for microcomputers.

A BASIC computer program designed to facilitate analysis of twin data is presented. The program estimates genetic parameters and tests their statistical significance based on the genetic and environmental hypothesis.

Computers↗
PubMed1981

A search for stratification-free association between plasma lipids and HLA using dizygotic twins.

A total of 71 pairs of like-sexed dizygotic twins were studied, comparing within-pair differences for plasma total, free and esterified cholesterol, and triglyceride with the number of HLA haplotypes the twins had in common. If associations are present between HLA and the blood lipids studied, the twins with no haplotypes in common would be expected to have the largest within-pair mean square, those with two in common the smallest, and those with one in common an intermediate value. No significant differences were found comparing within- pair mean squares for the variables studied.

Adolescent↗
PubMed1980

Data from kinships of monozygotic twins indicate maternal effects on verbal intelligence.

Familial resemblance in intellectual skills is well documented, but its interpretation is a source of continuing controversy. The critical problem is that a family's shared genes are confounded with its shared experiences, and controls possible in animal research (selective mating, cross-fostering, and uniform or randomised environments) do not directly apply to human subjects. Conventional twin and family methods reveal substantial genetic variance in intelligence quotient (IQ) test scores, but the same methods also document significant environmental influences. Research designs which can identify the nature of these environmental factors may effect progress in the 'IQ debate' (ref. 1). The families of monozygotic (MZ) twins provide a new research design which permits a unique assessment of maternal influences in quantitative traits. We describe here initial applications of the design to verbal IQ, with results suggesting that maternal effects significantly contribute to familial similarity in verbal intelligence.

Adolescent↗
PubMed1979

Effects of type of placentation on birthweight and its variability in monozygotic and dizygotic twins.

Birthweight was measured on 188 monochorionic monozygotic, 54 dichorionic monozygotic, 102 like-sexed dizygotic, and 94 unlike-sexed dizygotic liveborn twin pairs. Overall, males were found to be significantly heavier than females. These differences were not significant, however, when birthweights were compared within zygosity/chorion-type categories. Males were also characterized by a slightly greater overall total variance. Comparisons of intrapair variation of monochorionic and dichorionic monozygotic twins revealed significant differences between monochorionic pairs and dichorionic separate pairs and no significant differences between monochorionic pairs and dichorionic fused pairs. The results of this study suggest that placental proximity may have as important an influence on variation in birthweight as does the presence or absence of vascular anastomoses.

Birth Weight↗
PubMed1979

Genetic structure of the Queckchi Indians. Dental microdifferentiation.

Nine oral morphologic characters were investigated. Their frequencies are compared with those published for other populations. The possibility of using such characters to estimate genetic distance between populations is discussed and the conclusion is reached that, although previous studies have suggested this to be a valid approach, further studies testing this subject are needed.

Adolescent↗
PubMed1979

Twin data analysis.

Explore the source record for details and available documents.

Aryl Hydrocarbon Hydroxylases↗
PubMed1978

Prenatal ultrasonic diagnosis of epignathus.

This case demonstrated a mass seen on an ultrasound scan performed prior to amniocentesis to determine fetal maturity. It emphasizes the importance of scanning the entire contents of the amniotic sac rather than simply looking at the portion for which the examination was ordered. It is important to recognize such lesions to prepare for adequate management of the airway in the neonate, to prepare for surgical excision as soon as feasible, and to prepare the family for the birth of a baby with a congenital abnormality.

Adult↗
PubMed1977

Genetic variance of erythrocyte parameters in adult male twins.

Erythrocyte count, hematocrit, mean corpuscular volume and reticulocyte counts were measured in 59 pairs of monozygotic (MZ) and 69 pairs of dizygotic (DZ) adult, Caucasian male twins. The means of MZ and DZ twins were not significantly different for any of the traits measured. Erythrocyte count and mean corpuscular volume had significant estimates of genetic variance (P less than 0.05).

Adult↗