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H Kim

Publications and source records attributed to H Kim.

At least 487 records · Page 27Linked to original sources

Role of nitric oxide in oxidative damage in isolated rabbit gastric cells exposed to hypoxia-reoxygenation.

The present study aimed to investigate the role of nitric oxide on the oxidative damage in isolated rabbit gastric cells exposed to hypoxia-reoxygenation. Nitric oxide synthesis modulators such as L-arginine and NG-nitro-L-arginine methyl ester, a nitric oxide donor, sodium nitroprusside, and superoxide dismutase were used to treat the cells, and the synthesis and secretion of mucus, lipid peroxide production, and glutathione contents of the cells were determined. As a result, hypoxia-reoxygenation decreased nitric oxide production and the synthesis and secretion of mucus, as well as glutathione contents of gastric cells, but hypoxia-reoxygenation increased lipid peroxide production. Pretreatment with L-arginine, a substrate for nitric oxide synthase, sodium nitroprusside, and superoxide dismutase prevented the increase in lipid peroxide production and the decreases in glutathione contents, as well as the synthesis and secretion of mucus induced by hypoxia-reoxygenation. However, NG-nitro-L-arginine methyl ester, a nitric oxide synthase inhibitor, had no effect on these alterations. In conclusion, nitric oxide has an antioxidant defensive role on gastric cells by maintaining mucus and glutathione.

Animals↗

Clinical significance of clonality in thyroid nodules.

BACKGROUND: Many different neoplastic and hyperplastic thyroid diseases present with clinically apparent thyroid nodules. Clonality analysis indicates whether a nodule arises from the polyclonal proliferation of a group of cells or forms a clone from a genetically altered cell and thus provides objective information on the origin of the thyroid nodules. Clonality was studied in thyroid nodules using the polymerase chain reaction (PCR) assay in the X-linked human androgen receptor (HUMARA) gene by random X chromosome inactivation in women. METHODS: DNA samples were obtained from 28 nodules in 21 women. All nodules and non-tumour thyroid tissues were fractioned selectively under a cryostat. Genomic DNA was isolated and digested with HhaI. PCR amplification of the HUMARA locus was performed using PCR mixtures containing [alpha-32P]2'-deoxycytidine 5'-triphosphate. The PCR products were analysed by denaturing gel electrophoresis. RESULTS: The HUMARA alleles were heterogeneous in 18 of 21 patients. Among the 23 nodules from 18 patients, all of the eight papillary thyroid carcinomas were monoclonal. Two solitary nodules from follicular adenomas were monoclonal. Of the 13 follicular nodules from nodular goitres, ten were polyclonal and three were monoclonal. The monoclonal follicular nodules were larger in size (3.5 versus 2.0 cm, P< 0.05) and had a tendency towards more cystic changes than polyclonal nodules. CONCLUSION: PCR-based clonality study of thyroid nodules may help to distinguish hyperplastic from neoplastic nodules.

Adenoma↗

The value of classifying interstitial pneumonitis in childhood according to defined histological patterns.

AIMS: Interstitial pneumonitis in children is very rare and most cases have been classified according to their counterparts in adults, although the term 'chronic pneumonitis of infancy' has recently been proposed for a particular pattern of interstitial lung disease in infants. We reviewed our paediatric cases of interstitial pneumonitis, first, to look at the spectrum of histological patterns found in this age group and, second, to determine whether the classification of such cases in childhood is both appropriate and worthwhile. METHODS AND RESULTS: Twenty-five of 38 open lung biopsies showed an overlapping spectrum of interstitial pneumonitis, including three cases that fulfilled the histological criteria for chronic pneumonitis of infancy. There were 11 cases of reactive pulmonary lymphoid hyperplasia (either lymphoid interstitial pneumonitis or follicular bronchiolitis), five of which were associated with abnormalities of the immune system. Four cases were classified as desquamative interstitial pneumonitis and the remaining seven cases were classified as nonspecific interstitial pneumonitis. There were no cases with the histological features of usual interstitial pneumonitis. Most patients responded to steroids but tended to have a residual deficit in lung function. Mortality appeared to be associated with presentation at a young age. CONCLUSION: Classification of interstitial pneumonitis according to their adult counterparts is appropriate for this younger age group and can provide valuable information for the clinician. The term 'chronic pneumonitis of infancy' refers to a specific histological pattern, but whether it represents a separate disease or a reflection of pulmonary immaturity remains to be proven.

Adolescent↗

Inhibition of the induction of the inducible nitric oxide synthase in murine brain microglial cells by sodium salicylate.

The induction of the inducible nitric oxide synthase (iNOS) has been proposed to play a role in a variety of inflammatory diseases. Sodium salicylate (NaSal) is the most commonly used anti-inflammatory agent. We investigated whether NaSal can diminish the induction of iNOS in murine brain microglial cells. In primary cultures, interferon-gamma (IFN-gamma) or lipopolysaccharide (LPS) separately did not stimulate nitric oxide (NO) production, whereas IFN-gamma combined with LPS synergistically induced iNOS. NaSal inhibited both the production of NO and expression of iNOS in microglial cells. Synergy between IFN-gamma and LPS was mainly dependent on tumour necrosis factor-alpha (TNF-alpha) secretion as the increase of the induction of the iNOS by IFN-gamma plus LPS was associated with the increase of TNF-alpha secretion and IFN-gamma plus LPS-induced TNF-alpha secretion by microglial cells was decreased by the treatment with NaSal. These results suggest a possible use of NaSal in managing inflammation of the central nervous system through inhibition of the iNOS induction.

Animals↗

Ca2+-mediated activation of c-Jun N-terminal kinase and nuclear factor kappa B by NMDA in cortical cell cultures.

We examined the possibility that c-Jun N-terminal kinase (JNK) and nuclear factor kappaB (NF-kappaB) might be involved in intracellular signaling cascades that mediate NMDA-initiated neuronal events. Exposure of cortical neurons to 100 microM NMDA induced activation of JNK within 1 min. Activity of JNK was further increased over the next 5 min and then declined by 30 min. Similarly, ionomycin, a selective Ca2+ ionophore, induced activation of JNK. The NMDA-induced activation of JNK was abrogated in the absence of extracellular Ca2+, suggesting that Ca2+ entry is necessary and sufficient for the JNK activation. Immunohistochemistry with anti-NF-kappaB antibody demonstrated nuclear translocation of NF-kappaB within 5 min following NMDA treatment. NMDA treatment also enhanced the DNA binding activity of nuclear NF-kappaB in a Ca2+-dependent manner. Treatment with 3 mM aspirin blocked the NMDA-induced activation of JNK and NF-kappaB. Neuronal death following a brief exposure to 100 microM NMDA was Ca2+ dependent and attenuated by addition of aspirin or sodium salicylate. The present study suggests that Ca2+ influx is required for NMDA-induced activation of JNK and NF-kappaB as well as NMDA neurotoxicity. This study also implies that aspirin may exert its neuroprotective action against NMDA through blocking the NMDA-induced activation of NF-kappaB and JNK.

Animals↗

A randomized, prospective, comparative study of manual and automated renal biopsies.

A percutaneous renal biopsy can be performed in several ways, including using a spring-loaded biopsy gun. As this form of renal biopsy has become more popular, a controversy has developed regarding tissue adequacy and the incidence of complications. To compare these two aspects in an automated biopsy and a manual biopsy, we studied 166 patients assigned to one of the two renal biopsy methods. In a randomized, prospective manner from June 1994 until February 1997, group 1 (67 patients) received a 14 G Tru-cut needle (Baxter, Deerfield, IL) manual biopsy while group 2 (99 patients) received an 18 G automated gun biopsy. There was no difference in sex, age, hemoglobin level, prothrombin time, partial thromboplastin time, or diastolic and systolic blood pressure prebiopsy in groups I and II. Indications for biopsy were proteinuria (38%), proteinuria accompanied by hematuria (31.3%), acute renal failure (9.6%), lupus nephropathy (9.6%), chronic renal failure (6%), and hematuria only (5.4%). In group I, the number of cores was 1.88 +/- 0.56, the glomeruli obtained were 27.3 +/- 13.8, and the number of glomeruli per core were 15.3 +/- 8.4. In group II, the values were 2.37 +/- 0.88, 20.7 +/- 11.1, and 9.95 +/- 6.9, respectively. These results showed a statistically significant difference (P < 0.05). In all cases, pathological diagnosis was possible. The histology showed IgA nephropathy in 25.9%, minimal change disease in 16.3%, lupus nephritis in 11.4%, membranous glomerulonephropathy in 9.3%, membranoproliferative glomerulonephritis in 5.4%, and others. The incidence of postbiopsy hematoma was marginally greater in group I (22.3% v 11.1%) and the area of perirenal hematoma shown on ultrasound 24 hours postbiopsy was larger in group I, as well (848 +/- 623 mm2 v 338 +/- 260 mm2). Hematocrit levels before and after biopsy showed a significant difference (34.9% +/- 7.9% and 34.0% +/- 7.6%, respectively; P < 0.05) in group I, but no significant difference was observed in group II (35.1% +/- 7.0% and 34.7% +/- 6.9%). Both techniques rendered adequate tissue sampling, but the extent of bleeding was more severe with the manual 14 G Tru-cut needle biopsy.

Acute Kidney Injury↗

A computational and perceptual account of motion lines.

To indicate motion in a static drawing, artists often include lines trailing a moving object. The use of these motion lines is notable because they do not seem to be related to anything in the optic array. The dynamic behavior of a neural-network model for contour detection is analyzed and it is shown that it generates trails of oriented responses behind moving stimuli. The properties of the oriented response trails are shown to correspond to motion lines. The model generates trails of different orientations depending on the speed and length of the movement, and thereby predicts different uses of two types of motion lines. The model further predicts that motion lines should bias real motion in some situations. An experiment relating motion lines to ambiguous motion percepts demonstrates that motion lines contribute to motion percepts.

Humans↗

Relationship of apolipoprotein E phenotypes to serum lipid and lipoprotein levels in Japanese schoolchildren.

The distribution of apolipoprotein (apo) E phenotypes was investigated in Japanese schoolchildren and an attempt was made to determine whether the apoE phenotypes influence the serum levels of lipid and lipoprotein. The subjects were 289 children from a junior high school (145 M, 144 F, aged 12-13 y). The E3/3 phenotype was demonstrated in 69.9%, E4/3 in 18.7%, E2/3 in 9.0%, E4/2 in 1.4%, E4/4 in 0.7% and E5/4 in 0.3%. E2/2 was not detected. Serum levels of total cholesterol and low-density lipoprotein-cholesterol were progressively lower in the phenotypes E4/3, E3/3 and E2/3. The serum level of high-density lipoprotein-cholesterol showed a progressive increase in the same order. In conclusion, Japanese schoolchildren with E4/3 already had an atherogenic serum lipid profile.

Adolescent↗

Cloning and expression of a Clostridium thermocellum xylanase gene in Escherichia coli.

A Clostridium thermocellum xylanase gene, designated xynX, was cloned in Escherichia coli and was categorized a novel gene as a result of the comparison of restriction patterns of the C. thermocellum xylanase genes so far reported. The xynX gene encodes a xylanase having the molecular weight of 105 kilodaltons. A number of smaller truncated proteins with activities towards 4-methylumbelliferyl-beta-D-cellobioside and xylan were also produced. The enzyme hydrolyzed xylan to xylo-oligosaccharide, indicating typical activity of endo-beta-1,4-xylanase. This endoxylanase hydrolyzed carboxymethylcellulose without notable reduction of the viscosity as an exo-beta-1,4-glucanase, even though the enzyme exhibited very low levels of activity against other soluble and insoluble cellulosic substrates.

Carboxymethylcellulose Sodium↗

Mechanisms of action of the soy isoflavone genistein: emerging role for its effects via transforming growth factor beta signaling pathways.

The soy isoflavone genistein attenuates growth factor- and cytokine-stimulated proliferation of both normal and cancer cells. This article reviews our current understanding of the potential mechanisms of action of genistein. In membrane preparations from mammalian cells, genistein is a potent and specific inhibitor of tyrosine autophosphorylation of the epidermal growth factor (EGF) receptor. However, in several cell systems in which it inhibits growth, genistein does not alter tyrosine phosphorylation of the EGF receptor or other tyrosine kinase substrates thought to be involved in signal transduction pathways, suggesting that other mechanisms may be responsible for its action. Alternatives include inhibition of DNA topoisomerase II activity, regulation of cell cycle checkpoints, and antiangiogenic and antioxidant activity. Experiments in our laboratory suggest a new concept, that genistein may inhibit cell growth by modulating transforming growth factor (TGF) beta1 signaling pathways. Such a link between genistein action and TGFbeta1 function is supported by preliminary results of studies in patients with hereditary hemorrhagic telangiectasia (a genetic disorder involving mutations in proteins that regulate TGFbeta receptor complex formation and signaling) in which several patients had dramatic attenuation of their symptoms after 1 wk of ingesting soy-based beverages. These preclinical studies in combination with our cell culture data suggest that the mechanism of genistein involves, if not requires, TGFbeta1-signaling.

Animals↗

Insulin-like growth factor binding protein-3 mRNA expression in endothelial cells of the primate corpus luteum.

Luteinization is associated with endothelial cell proliferation as part of the extensive angiogenesis necessary to maintain corpus luteum function. However, following luteal demise, the vasculature regresses and the endothelial cells disappear. In the rat corpus luteum, the endothelial cells express high concentrations of insulin-like growth factor-binding protein-3 (IGFBP-3) during luteolysis, suggesting a role of IGFBP-3 during endothelial cell loss. The aim of the present study was to determine the occurrence and location of the messenger ribonucleic acid (mRNA) for IGFBP-3 in the primate corpus luteum, and to determine whether or not induction of luteal regression is associated with changes in localization of the message. Marmoset corpora lutea were studied throughout the cycle. The effects of induced luteolysis were examined 12 h or 24 h after treatment with either a gonadotrophin-releasing hormone antagonist or a prostaglandin F2alpha analogue, administered during the mid-luteal phase. High IGFBP-3 expression was recorded in the endothelial cells of the majority of microvessels and a minority of capillaries surrounding the lutein cells in all functionally active corpora lutea. Expression declined markedly in regressing corpora lutea of the late follicular phase. Expression of the IGFBP-3 mRNA in lutein cells in the control corpus luteum was extremely rare. There were no major differences in the degree and pattern of IGFBP-3 expression as a consequence of induced luteal regression although there was an apparent increase in the number of capillary endothelial cells expressing. Induction of luteolysis resulted in expression in a minority of lutein cells. These results support the concept that IGFBP-3 has an autocrine/paracrine role in regulating various cell types in the primate corpus luteum, including endothelial cells. However, expression of IGFBP-3 mRNA throughout the luteal phase suggests it may regulate angiogenesis and luteal function rather than endothelial cell death and luteolysis.

Animals↗

Hepatitis B vaccination and reduced risk of primary liver cancer among male adults: a cohort study in Korea.

BACKGROUND: Primary liver cancer is an important health problem in Korea, where hepatitis B virus (HBV) infection is prevalent. The authors conducted a prospective cohort study to evaluate the protective effect of HBV vaccination against liver cancer in adults. METHODS: A total of 370,285 males aged > or = 30 comprised the study population. They were clinically free of liver diseases, and had not been vaccinated against HBV at enrolment. The results of HBV surface antigen (HBsAg) and antibody to HBsAg (anti-HBs) marker positivity and those of the vaccination programme which took place during 1985 were used for the construction of the cohort. About 5% (n = 18,914) were HBsAg positive, 78,094 were anti-HBs positive, and 273,277 were negative for both. Among the candidates for HBV vaccination (n = 273,277), 35,934 (13.2%) people had been vaccinated against HBV during 1985. Cases of liver cancer were ascertained by record linkage and from medical records covering 1986-1989. A multivariate log-linear model was used to test statistical significance and to estimate relative risks (RR). RESULTS: The total follow-up period was 1,404,566 person-years, with an average of 3 years and 10 months. A total of 302 incident cases were ascertained. The overall incidence rate of liver cancer was 21.7 per 100,000 person-years. With reference to the incidence level among the unvaccinated and uninfected, the RR of primary liver cancer among the chronically infected and that of the unvaccinated and infected was 18.1 (95% CI: 14.2-22.9) and 0.34 (95% CI: 0.19-0.60), respectively. The RR among the vaccinated group was 0.58 (95% CI: 0.31-1.09). CONCLUSIONS: This study suggested that artificial immunization through HBV vaccination, even in adulthood, reduces the risk of liver cancer. It might also offer a practicable means of primary prevention, especially in areas with hyperendemicity of HBV infection.

Adult↗

Interaction of glucagon with dimyristoylphosphatidylcholine in vesicular and discoidal complexes.

Glucagon fragments dimyristoylphosphatidylcholine liposomes into discoidal complex under appropriate conditions. The concentration of glucagon required to fragment the vesicles increases with increasing pH, which appears to be related to the glucagon binding. It was also observed that the fragmentation is facilitated by NaCl, which is also due to increased glucagon binding. From the quenching of Trp fluorescence by doxyl group located at various positions of the acyl chain of the lipid, Trp of glucagon was found to be located close to the bilayer surface in the vesicular complex. However, the Trp fluorescence was quenched by the doxyl group in the discoidal complex to an equal extent regardless of the position of this spin label in the acyl chain. This and the results of second derivative UV spectroscopy of Tyr suggested that segments including Tyr-13 and Trp-25 are involved in the discoidal complex formation and that the orientation of glucagon is not normal to the bilayer surface.

Animals↗

Opine catabolic loci from Agrobacterium plasmids confer chemotaxis to their cognate substrates.

Opines are carbon compounds produced by crown galls and hairy roots induced by Agrobacterium tumefaciens and A. rhizogenes, respectively. These novel condensation products of plant metabolic intermediates are utilized as nutritional sources by the Agrobacterium strains that induced the growths. Thus, opines are thought to favor the propagation of agrobacteria in the tumorsphere. Certain Agrobacterium strains were chemoattracted to opines. The chemotactic activities to octopine, to nopaline, to mannopine, and to agrocinopines A + B were dependent on the type of the Ti plasmid present in the bacterium. The determinants for chemotaxis to these opines were localized to the regions of the octopine- and nopaline-type Ti plasmids coding for transport and catabolism of that opine. An insertion in accA, which encodes the periplasmic binding protein for agrocinopines A + B, abolished chemotaxis while an insertion in accC, which encodes a component of the transport system, and an insertion in accF, which encodes a function required for agrocinopine catabolism, did not affect chemotaxis to this opine. Thus, transport and catabolism of these opines are not required for the chemotactic activity. Analyses of subclones of the acc region confirmed that accA is the only gene required from the Ti plasmid for chemotaxis to agrocinopines A + B.

Carbon↗

Endogenous insulin-like growth factor-I is obligatory for stimulation of rat inhibin alpha-subunit expression by follicle-stimulating hormone.

Insulin-like growth factor-I (IGF-I) is essential for FSH-dependent steroidogenesis by rat granulosa cells (GC), but whether IGF-I is required for other FSH-dependent functions is unknown. To investigate the role of IGF-I in the mechanisms of FSH-stimulated inhibin alpha-subunit (Inh-alpha) production, rat GC were cultured with FSH, IGF-I, insulin-like growth factor-binding protein (IGFBP)-4, IGFBP-5, and/or anti-IGF-I antibody. Inh-alpha protein and mRNA levels were measured in conditioned medium and cells by Western immunoblotting and Northern analysis, respectively. Inh-alpha expression was increased by FSH (3.5-fold) and IGF-I (2.5-fold), and the effects were dose and time dependent. FSH stimulation of Inh-alpha was attenuated by IGFBP-4 or -5 in a dose-dependent fashion, and the effects were reversed by IGF-I. Anti-IGF-I antibody mimicked the inhibitory effects of IGFBP-4 and -5. Forskolin, cholera toxin, and 8-bromo-cAMP increased Inh-alpha production approximately 3.5-fold, and the effects were blocked by IGFBP-4 or -5. Increases in Inh-alpha by FSH, IGF-I, forskolin, cholera toxin, and 8-bromo-cAMP were totally blocked by the protein tyrosine kinase inhibitor, tyrphostin A23. In summary, these results suggest that the stimulation of Inh-alpha expression by FSH requires activation of protein tyrosine kinases by endogenously produced IGF-I. We propose that the IGF-I signaling is obligatory for FSH stimulation of Inh-alpha expression in rat GC.

8-Bromo Cyclic Adenosine Monophosphate↗

Activin-induced inhibin alpha-subunit production by rat granulosa cells requires endogenous insulin-like growth factor-I.

Inhibin-alpha subunit (Inh-alpha) gene expression is important for granulosa cell (GC) differentiation and prevention of ovarian tumorigenesis. Studies on Inh-alpha regulation have implicated activin and insulin-like growth factor-I (IGF-I) in the mechanisms of expression. Here we present evidence that endogenously produced IGF-I plays an obligatory role in activin-induced Inh-alpha production. Primary cultures of rat GC were incubated with increasing concentrations of various regulatory molecules, and the levels of Inh-alpha protein and its mRNA were measured in conditioned medium and cells, respectively. Recombinant activin A stimulated Inh-alpha expression, and the effects were dose- and time-dependent. The receptor tyrosine kinase inhibitor tyrphostin A23 caused a dose-dependent inhibition of activin-dependent Inh-alpha expression, whereas the inactive isomer, A63, had no effect. The stimulatory effect of activin was also blocked in a dose-dependent manner by added IGF binding protein-4 or -5, and the effects were reversed by IGF-I. Moreover, increasing concentrations of an anti-IGF-I antibody had a similar inhibitory effect on activin-stimulated Inh-alpha expression. Collectively, these results suggest, for the first time, that endogenously produced IGF-I is required for activin stimulation of Inh-alpha expression in cultured rat GC.

Activins↗

Pigmented ("black") extraadrenal paraganglioma.

A pigmented ("black") extraadrenal paraganglioma was discovered incidentally in a 57-year-old woman during ultrasonography. The tumor was located in the retroperitoneum near the superior border of the right kidney. Results of preoperative fine-needle aspiration and intraoperative frozen sectioning of the resected jet-black tumor (13 cm in diameter, 225 g) were both interpreted as suspicious for malignant melanoma. Histomorphology and immunohistochemistry were diagnostic for paraganglioma. Electron microscopy showed numerous dense-core neurosecretory-type granules, as well as abundant, larger pleomorphic electron-dense granules; most were consistent with lipofuscin or neuromelanin. No melanosomes or premelanosomes were identified. Histochemical stains showed that the pigment most likely is neuromelanin, a nonenzymatic or oxidative waste product of catecholamine metabolism. Eighteen other examples of pigmented paragangliomas have been reported in various sites in the English literature during the last 12 years; most indicate the presence of melanosomes or premelanosomes using electron microscopy, whereas in a minority of cases the pigment has not been characterized rigorously. Common embryogenesis from neural crest may help explain the overlapping phenotype of melanocytes and cells of paraganglioma.

Female↗