PubMed Health⌕ Search

Biomedical subjects

I S Kim

Publications and source records attributed to I S Kim.

At least 19 recordsLinked to original sources
PubMed1992

Association of titin and myosin heavy chain in developing skeletal muscle.

To understand molecular interactions that organize developing myofibrils, we examined the biosynthesis and interaction of titin and myosin heavy chain in cultures of developing muscle. Use of pulse-labeling, immunoprecipitation, and a reversible cross-linking procedure demonstrates that within minutes of synthesis, titin and myosin heavy chain can be chemically cross-linked into very large, detergent-resistant complexes retaining many features of intact myotubes. These complexes, predominantly of titin and myosin, occur very early in myofibrillogenesis as well as later. These data suggest that synthesis and assembly of titin and myosin are temporally and spatially coordinated in nascent myofibrils and support the hypothesis that titin molecules help to organize sarcomere formation.

Animals↗
PubMed1992

Receptors for platelet-derived growth factor on microvascular endothelial cells.

Endothelial cells are widely thought to be unresponsive to platelet-derived growth factor (PDGF) and devoid of PDGF receptors. However, in examining the growth factor responses of microvascular endothelial cells isolated from human omental adipose tissue, we detected PDGF-induced tyrosine phosphorylation of an 180-kD glycoprotein, subsequently identified as the cellular receptor for PDGF by specific immunoprecipitation. Scatchard analysis of 125I-PDGF binding to human microvascular endothelial cells revealed 30,000 PDGF receptors/cell with a kD of 0.14 nM. PDGF stimulated tyrosine phosphorylation of PDGF and other cellular proteins in a dose- and time-dependent manner, with half-maximal receptor phosphorylation occurring at 0.3 nM recombinant human PDGF-BB within 1 min of PDGF exposure. Normal cellular consequences of receptor activation were also observed, including tyrosine phosphorylation of a 42-kD protein and serine phosphorylation of ribosomal protein S6. Furthermore, PDGF was mitogenic for these cells. The finding of functional PDGF receptors on human microvascular endothelial cells suggests an important direct role for PDGF in neovascularization.

Adipose Tissue↗
PubMed1992

Adduct formation at C-8 of guanine on in vitro reaction of the ultimate form of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine with 2'-deoxyguanosine and its phosphate esters.

We examined the reactivity of the N-hydroxyamino derivative of a carcinogenic heterocyclic amine, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), after its O-acetylation with four 2'-deoxyribonucleoside 3'-monophosphates. 32P-Postlabeling analysis demonstrated that the levels of adducts with 2'-deoxyguanosine 3'-monophosphate were much higher than those with the other three nucleotides. 1H-NMR, mass spectral and UV absorption spectral analyses of the major adducts formed by N-acetyoxy-PhIP with 2'-deoxyguanosine and with its phosphate esters indicated that PhIP bound at the C-8 position of guanine, as previously demonstrated with other heterocyclic amines.

Acetic Anhydrides↗
PubMed1992

Expression and amplification of cellular oncogenes in human developing placenta and neoplastic trophoblastic tissue.

To confirm the expression of cellular oncogenes during normal development, their differential RNA levels in developing human placenta have been studied using radioactive probes such as v-abl, v-erbA, v-fms, v-mos, v-myc, N-ras and v-src. The c-mos and N-ras genes are expressed and amplified at high levels especially in term placenta, while c-abl, and c-erbA are expressed constantly during development. These findings indicate that c-mos and N-ras genes may be closely linked to normal differentiation, although c-abl and c-erbA may participate in overall developmental processes. In contrast, transcripts of c-myc and c-src are enhanced at first trimester and decreased sequentially thereafter, showing that these genes may play a role in early proliferation. Expression patterns of c-fms gene are same as that of c-myc and c-src except reelevation at term. In addition, to characterize the effect of cellular oncogene expression has been also examined in hydatidiform mole and tumor cells such as BeWo and choriocarcinoma. All cellular oncogenes examined in this study were significantly overexpressed. Thus, our results suggest that cellular oncogene activation may be strongly associated with neoplastic change of trophoblast.

DNA Probes↗
PubMed1992

The measurement of fibronectin concentrations in human aqueous humor.

The concentrations of fibronectin in aqueous humor, measured by ELISA which was developed to detect fibronectin, ranged from 5 ng/ml to 100 ng/ml. Aqueous humor was aspirated from human eyes with cataracts and glaucomas using a 26 gauge needle through the peripheral cornea before making the limbal incision into the anterior chamber during surgery. The results of the study show that the average concentration and standard deviation of fibronectin was 0.136 +/- 0.192 microgram/ml in cataract eyes, and 0.962 +/- 0.918 microgram/ml in glaucoma eyes respectively. There was a statistically significant difference between both groups (p = 0.000). However, no significant differences according to age and sex were noted. There was no influence due to preoperative intravenous mannitol injection on fibronectin concentration. The source of aqueous fibronectin is still not clearly known and the mechanism of the higher concentration of fibronectin in glaucoma has not been clearly disclosed, however it is thought that normally present fibronectin is accumulated in the anterior chamber because it can not pass the aqueous outflow pathway, or that fibronectin production may be increased in glaucoma.

Adolescent↗
PubMed1992

Clinical efficacy of topical homologous fibronectin in persistent corneal epithelial disorders.

The clinical efficacy was investigated of topical homologous fibronectin on persistent corneal epithelial defects of various etiologies. Fibronectin was purified from blood bank homologous plasma by gelatin-Sepharose 4B affinity chromatography. Twenty eight eyes of twenty five patients with persistent corneal epithelial defects and sterile corneal ulcers that failed to improve with standard therapy were treated by the instillation of homologous fibronectin eyedrops 5 times a day (500 micrograms/ml). Complete reepithelialization was achieved in all patients except two eyes due to uncontrolled glaucoma and the taking of steroids. The healing time tended to be different depending on the duration of persistent corneal epithelial defects and the severity of underlying diseases. The mean +/- standard deviation duration of epithelial defect was 68.18 +/- 77.80 days. Average healing time was 42.07 +/- 17.47 days. Ocular symptoms were relieved significantly and no side effects were observed. Over an average follow-up period of about 8 months, two cases of recurrences were noted. These results show that homologous fibronectin was also effective in patients with persistent corneal epithelial defects and corneal ulcers.

Administration, Topical↗
PubMed1992

Malignant lymphomas of the nasal cavity and Waldeyer's ring--clinicopathologic and immunohistochemical study.

The clinicopathologic and immunohistochemical finding of 10 cases of nasal non-Hodgkin's lymphoma (NHL) and 23 cases of Waldeyer's ring NHL were studied. Immunohistochemically, nasal NHL expressed T-cell markers exclusively, whereas the NHL of Waldeyer's ring were of both T-cell (56.5%) and B-cell lineages (43.5%). Angioinvasiveness by tumor cells was exclusively noted in the T-lineage lymphomas. Epithelial hyperplasia, epitheliotropism by tumor cells, and extensive invasion of adjacent normal tissue were more prominent in T-cell lymphomas than in B-cell lymphomas. T-lineage lymphomas showed distant extranodal spread pattern involving the skin, soft tissue, stomach, spleen, and the liver, whereas B-lineage lymphomas tended to localize in the lymph nodes. The survival rate of Nasal NHL was similar to that of Waldeyer's ring NHL. Although not statistically significant because of small sample numbers, immunophenotype, histologic groups of monomorphic lymphoma, and stage had prognostic importance. In general, T-lineage lymphomas presented with a higher stage than B-lineage lymphomas (p < 0.05)-and overall survival was poor. Stage I disease showed a much more favorable prognosis than stage II disease. Monomorphic lymphomas had a shorter survival than polymorphic reticulosis (PR) or lymphomas with features of PR. This result in conjunction with the morphologic transition between them suggested that monomorphic lymphoma may represent the most advanced stage in the spectrum of PR, lymphoma with features of PR, and monomorphic lymphoma.

Adolescent↗
PubMed1991

Human microvascular endothelial cells express receptors for platelet-derived growth factor.

Endothelial cells have been widely thought to be unresponsive to platelet-derived growth factor (PDGF, a major growth factor released from stimulated platelets at the sites of vascular insults) and devoid of PDGF receptors. Nevertheless, in examining the growth-factor responses of microvascular endothelial cells isolated from human omental adipose tissue, we were surprised to detect PDGF-induced tyrosine phosphorylation of a 180-kDa glycoprotein, subsequently identified as the cellular receptor for PDGF by specific immunoprecipitation. Scatchard analysis of 125I-labeled PDGF binding to human microvascular endothelial cells revealed 30,000 PDGF receptors per cell with a Kd of 0.14 nM. PDGF stimulated tyrosine phosphorylation of PDGF receptors and other cellular proteins in a dose- and time-dependent manner, with half-maximal receptor phosphorylation occurring at 0.3 nM recombinant human PDGF (B chain) and a less than or equal to 1-min exposure to PDGF. Normal cellular consequences of receptor activation were also observed, including tyrosine phosphorylation of a 42-kDa protein and serine phosphorylation of ribosomal protein S6. Furthermore, PDGF was mitogenic for these cells. Microvascular endothelial cells play a central role in neovascularization required for wound healing and solid tumor growth. Thus, the discovery of functional PDGF receptors on human microvascular endothelial cells suggests a direct role for PDGF in this process.

Cell Division↗
PubMed1991

Seroprevalence of antibody against hepatitis C virus (anti-HCV) in various groups of individuals in Korea.

We studied the prevalence of anti-HCV in 585 sera from various individuals, using enzyme immunoassay (EIA, Abbott Lab.). Anti-HCV was detected in 16 (10.7%) out of the 150 patients with HBsAg positive liver diseases diagnosed by liver biopsy and they consisted of none out of 10 acute viral hepatitis, 3 out of 15 chronic persistent hepatitis, 4 out of 50 chronic active hepatitis, 2 out of 32 liver cirrhosis, and 7 out of 43 hepatocellular carcinoma. Anti-HCV was detected in 43 (45.3%) out of 95 patients with HBsAg negative liver diseases diagnosed by liver biopsy and they consisted of 5 out of 8 acute viral hepatitis, 2 out of 10 chronic persistent hepatitis, 17 out of 30 chronic active hepatitis, 4 out of 15 liver cirrhosis, and 15 out of 32 hepatocellular carcinoma. Anti-HCV was detected in 22 (38.6%) out of 57 hemodialysis patients, in 3 (6.7%) out of 45 kidney transplants, in 2 (11.1%) out of 18 fatty liver diagnosed by liver biopsy, in 2 (1.3%) out of 150 healthy blood donors, in none out of 40 healthy volunteers, in 6 (31.6%) out of 19 rheumatoid arthritis and in 6 (54.5%) out of 11 systemic lupus erythematosis cases. There were familial clusters of chronic liver diseases in 4.7% of patients with HBsAg negative/anti-HCV positive chronic liver diseases, while in 19.4% of patients with HBsAg positive/anti-HCV negative liver diseases. Incidence of anti-HCV within patients with HBsAg positive liver diseases was higher in HBsAg negative patients than in HBsAg positive patients (17.6% and 10.3%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Chi-Square Distribution↗
PubMed1991

Mutagenicity of Maillard reaction products from D-glucose-amino acid mixtures and possible roles of active oxygens in the mutagenicity.

The mutagenicity for Salmonella typhimurium TA100 without S9 mix of Maillard reaction products (MRP) obtained from equimolar amounts of glucose and amino acids under different pHs was investigated. MRP derived from arginine and lysine exhibited the strongest mutagenicity, and weaker mutagenicity was shown by the mixtures with alanine, serine, threonine and monosodium glutamate. MRP from proline and cysteine had no detectable mutagenicity. Furthermore, glucose-arginine and glucose-lysine reaction mixtures, which presented a marked mutagenicity, showed pH- and browning intensity-dependent expression of their mutagenic activities. The mutagenicity of MRP, especially glucose-arginine and glucose-lysine mixtures, was significantly suppressed by active oxygen scavengers such as cysteine, mannitol, alpha-tocopherol, catalase and superoxide dismutase (SOD) and reducing agents such as sodium bisulfite and glutathione. Among these desmutagenic factors tested, cysteine, catalase, sodium bisulfite and glutathione had higher desmutagenic activities than the others. Accordingly, it is assumed that the mutagenicity of MRP is due to the direct action of low-molecular-weight compounds such as carbonyls and heterocyclics produced by the Maillard reaction and is enhanced by active oxygens, especially singlet oxygen and hydrogen peroxide derived from their autoxidation.

Amino Acids↗
PubMed1991

Seasonal variations and trends in concentrations of filter-collected polycyclic aromatic hydrocarbons (PAH) and mutagenic activity in the San Francisco Bay area.

Air monitoring in the San Francisco Bay Area was carried out to measure outdoor community air concentrations of polycyclic aromatic hydrocarbons (PAH) and mutagenic activity (mutagenicity) in particulate organic matter (POM). Monitoring began in 1979 and is currently conducted at six stations. PAH and mutagenicity tests were performed on organic extracts prepared from high volume (hi-vol) filters composited every four months, by meterological season. PAH were determined by high pressure liquid chromatography (HPLC) with fluorescence and ultraviolet detection. Mutagenicity was measured in the Ames Salmonella bioassay using strain TA98 with and without metabolic activation. The nine-year mean concentration of benzo(a)pyrene (BaP) was 0.4 ng/m3. The mutagenicity of this amount of BaP accounted for only about 0.2% of the observed mutagenicity in POM and other measured PAH accounted for even less. Concentrations of PAH and mutagenicity were three to nine times higher during the winter than during other seasons. Year-to-year wintertime trends in several PAH were also seen. Early in the 1980s, winter concentrations of BaP and benzo (g,h,i)perylene increased. However since the mid-1980's, their concentrations have fallen. The decrease in PAH concentrations may be the result of an increasing proportion of vehicles with relatively low organic emissions. In contrast to PAH, mutagenicity did not show significantly year-to-year time trends.

Air Pollutants↗
PubMed1991

A case of primary T-cell lymphoma of the duodenum.

Primary malignant lymphoma located in the duodenum is a rarity. A case of primary lymphoma of the duodenum in a 27-year-old man, in which the 2 discrete masses of duodenal bulb and the second portion with pancreatic head invasion was found, is reported here. Immunohistochemical evaluation of the present case showed that lymphoma cells expressed the T-cell markers MT1 and UCHL1. Treatment consisted of pancreaticoduodenectomy followed by antineoplastic chemotherapy.

Adult↗
PubMed1990

Spectral perturbations and oligomer/monomer formation in 124-kilodalton Avena phytochrome.

We have studied the effects of pH, ionic strength, and hydrophobic fluorescence probes, 8-anilinonaphthalene-1-sulfonate (ANS) and bis-ANS, on the structure of intact (124-kDa) Avena phytochrome. The Pfr form of phytochrome forms oligomers in solution to a greater extent than the Pr form. Hydrophobic forces play a major role in the oligomerization of phytochrome, as suggested by fluorescence and monomerization by bis-ANS. However, electrostatic charges also take part in the phytochrome oligomerization. The partial proteolytic digestion patterns for the Pr and Pfr species are different, but binding of bis-ANS to the phytochrome abolishes this difference and yields an identical proteolytic peptide mapping for both spectral forms of phytochrome. This appears to result from bis-ANS binding at the carboxy-terminal domain, which induces monomerization of phytochrome oligomers. A second bis-ANS binding at an amino-terminal site blocks cleavage sites of trypsin and alpha-chymotrypsin. Bis-ANS especially blocks access of the proteases to the amino-terminal cleavage site that produces an early proteolytic product (114/118 kDa) on SDS gels. The bis-ANS binding does not, however, affect the proteolytic cleavage site that occurs in the hinge region between the two structural domains of phytochrome, the chromophore domain and the C-terminal non-chromophore domain. A chromophore binding site in the Pfr form is apparently exposed for preferential binding of bis-ANS, causing cyclization of the chromophore and bleaching of its absorbance at 730 nm. These observations have been discussed in terms of a photoreversible topographic change of the chromophore/apoprotein during the phototransformation of phytochrome.

Anilino Naphthalenesulfonates↗
PubMed1990

Benzene, benzo(a)pyrene, and lead in smoke from tobacco products other than cigarettes.

Benzene, benzo(a)pyrene (BaP), and lead in mainstream smoke from cigars, roll-your-own (RYO) cigarette and pipe tobaccos were sampled to evaluate their potential health significance. Results with reference cigarettes were consistent with published values, providing support for the methodology employed. The emissions of benzene and BaP, expressed as mass emitted per gram of tobacco consumed, were similar for all products evaluated; for benzene, the mean values for cigars, RYO cigarette and pipe tobaccos were 156 +/- 52, 68 +/- 11, and 242 +/- 126 micrograms/g, respectively. Mean values for BaP were 42 +/- 7 and 48 +/- 4 ng/g for cigars and RYO cigarette tobacco, respectively. Lead values were below the limit of reliable quantitation in all cases. The mean benzene concentrations in a puff ranged from 1 to 2 x 10(5) micrograms/m3 for cigars, RYO cigarette and pipe tobaccos. For BaP, the puff concentration averaged about 60 micrograms/m3 for cigars and RYO cigarette tobacco. The results suggest that smoking cigars, pipes or RYO cigarettes leads to potential exposures which exceed the No Significant Risk levels of benzene and BaP set pursuant to California's Proposition 65. These tobacco products are now required to bear a health hazard warning when sold in California. We recommend that this be adopted as national policy.

Benzene↗
PubMed1990

Topical fibronectin treatment in persistent corneal epithelial defects and corneal ulcers.

Topical fibronectin, autologous and homologous, was used to treat nine patients (eleven eyes) with persistent corneal epithelial defects and corneal ulcers that failed to improve with standard therapy. The fibronectin was purified from autologous and homologous plasma by gelatin-Sepharose 4B affinity chromatography and administered topically, 500 micrograms/ml five times a day, for three weeks. Complete or nearly complete reepithelialization was achieved in all patients regardless of the source of fibronectin, autologous or homologous. But healing times varied. The average healing time was 41.7 +/- 14.7 days (35.7 +/- 12.4 days for autologous, 50.8 +/- 14.4 days for homologous). Ocular symptoms were relieved significantly, and no side effects were observed. Over an average follow-up period of 5.2 months, no recurrences were noted. The results showed that homologous, as well as autologous, fibronectin was effective in patients with persistent corneal epithelial defects and corneal ulcers.

Administration, Topical↗
PubMed1990

Community-based eye health survey in areas of Buan-Kun and Dobong-Ku in Korea.

This survey comparing the primary causes of eye disease and visual impairment between rural and urban areas was conducted from the beginning of February through May of 1989. The outcome of that research on 686 residents (1372 eyes) of Buan-Kun, Chunbuk, and 997 residents (1994 eyes) of Dobong-Ku, Seoul, is as follows: 1. Of the basic ocular affections, pterygium was the most prevalent in Baun-Kun with 178 eyes (13.0%), while allergic and chronic conjunctivitis were in the majority in Dobong-Ku with 170 eyes (8.5%). 2. In causes of visual impairment, refractive error showed to be the main one in both Buan-Kun with 135 eyes (9.8%) and Dobong-Ku with 132 eyes (6.6%). 3. In rate of blindness, Buan-Kun had 7.0% monocular blindness and 3.2% of binocular blindness, while 4.1% of monocular blindness and 1.7% of binocular blindness were found in Dobong-Ku. 4. In causes of blindness, cataract (51.1%) was followed by macular degeneration (17.4%), corneal opacity (13.0%), and vascular retinopathy (9.8%) in Buan-Kun, while cataract (56.0%), macular degeneration (6.7%), corneal opacity (6.7%), and phthisis (6.7%) were recorded in that order in Dobong-Ku.

Adolescent↗
PubMed1990

[Effects of plasmapheresis on lymphocytic energy enzymes in hypertension].

Cytochemistry of peripheral blood lymphocyte enzymes was studied in 58 patients with State II essential hypertension (36 of these were treated with traditional hypotensive therapy and 22 with plasmapheresis + drug therapy). alpha-GPDH, LDH, and acid phosphatase activities were found reduced in these patients. The degree of the enzymic activity reduction (SDH included) depended on the disease standing and family history of patients. Plasmapheresis elevated the activities of energy enzymes and reduced arterial pressure, i.e. these parameters were in inverse correlation. In the patients treated by routine hypotensive therapy energy enzymes' activity was unchanged, despite the clinical effect.

Acid Phosphatase↗