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Biomedical subjects

J H Yoon

Publications and source records attributed to J H Yoon.

At least 91 records · Page 5Linked to original sources
PubMed1999

Sequence analysis of 16S rRNA genes amplified from two ribosomal RNA gene clusters of Bifidobacterium bifidum.

Two rRNA gene clusters were detected in the genome of Bifidobacterium bifidum KCTC 3202T using Southern blot analysis. To analyse the sequences of the 16S rRNA genes from rrnA and rrnB, 16S rDNAs were amplified by PCR using DNA fragments purified from gel slices containing each of the rRNA gene clusters. The amplified 16S rDNAs from rrnA and rrnB were cloned into vectors and three clones of each gene sequenced. The resultant sequences were confirmed by direct sequencing of the 16S rDNAs from rrnA and rrnB. Sequence differences were not found between rrnA and rrnB in 1488 bp of the 16S rRNA genes.

Bifidobacterium↗
PubMed1999

IGF-I and TGF-beta2 have a key role on regeneration of nitric oxide synthase (NOS)-containing nerves after cavernous neurotomy in rats.

The molecular mechanism of nitric oxide synthase (NOS)-containing nerve regeneration is still unknown. It is believed that growth factors are involved in this phenomenon. We investigated the change of NOS containing nerve fibers and the mRNA expression of insulin like growth factor (IGF)-I, nerve growth factor (NGF), transforming growth factor (TGF)-alpha, TGF-beta1, TGF-beta2, TGF-beta3, vascular endothelial growth factor (VEGF), endothelial NOS (eNOS) and neuronal NOS (nNOS) on the penis after cavernous nerve neurotomy in rats. Male rats were divided into four groups: (1) sham operation (n = 14); (2) unilateral neurotomy of a 5 mm segment of the cavernous nerve (n = 21); (3) unilateral neurotomy with growth hormone (n = 14); and (4) bilateral neurotomy (n = 21). Electrostimulation of the intact cavernous nerve or pelvic ganglion were performed at one, three and six months. Nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase staining and immunohistochemistry were used to identify NOS in the penis. The gene expression for growth factors, eNOS and nNOS were investigated in corporal tissue by reverse transcriptase-polymerase chain reaction (RT-PCR). One month after neurotomy, both unilateral and bilateral neurotomy groups showed significant decreases in NOS-containing nerve fibers on the dorsal and intracavernosal nerves on the side of neurotomy. Significantly lower mRNA expression of nNOS, IGF-I and TGF-beta2, higher mRNA expression of eNOS and VEGF189 were shown in these groups. At three months, the number of NOS-containing nerve fibers in the unilateral neurotomy group increased only slightly, while the GH-treated group showed a significant increase. At six months, those in the intracavernosal nerve only increased in a significant amount (P < 0.0001), however mRNA expression of nNOS, IGF-I and TGF-beta2 showed a significant increase as early as at three months. After bilateral neurotomy, the NOS-positive nerve fibers in the dorsal and intracavernosal nerve were significantly decreased at one month and remained so at six months; no erectile response could be elicited by pelvic ganglion stimulation. In the unilateral neurotomy group at six months, more NOS-positive neurons in the pelvic ganglia were found on the intact side than on the side of the neurotomy (P < 0.003), indicating that the regeneration derived from pelvic ganglion neurons on the intact side. Furthermore, electrostimulation in the unilateral neurotomy group revealed a greater maximal intracavernosal pressure and a shorter latency period at six months than at one month (P < 0.014, P < 0.001, respectively). These data suggest that IGF-I and TGF-beta2 may play a key role in the regeneration of nNOS-containing nerve fibers in the dorsal and intracavernosal nerves, and eNOS increases temporarily in the intracavernous involving VEGF189 after unilateral cavernous nerve injury.

Animals↗
PubMed1999

The role of growth factor on regeneration of nitric oxide synthase (NOS)--containing nerves after cavernous neurotomy in the rats.

Nitric oxide synthase (NOS) containing nerve regeneration can be seen six months after unilateral cavernous nerve neurotomy in rats. However, its molecular mechanism is still unknown. It is believed that growth factors are involved in this phenomenon. In this study we investigated the change of NOS containing nerve fibers and the RNA expression of insulin like growth factor (IGF)-I, nerve growth factor (NGF), transforming growth factor (TGF)-alpha, TGF-beta 1, TGF-beta 2. TGF-beta 3 and NOS on the penis after cavernous nerve neurotomy in rats. Male rats were divided into three groups: (1) sham operation (N = 10); (2) unilateral neurotomy of a 5 mm segment of the cavernous nerve (N = 15); and (3) bilateral neurotomy (n = 15). Electrostimulation of the intact cavernous nerve or pelvic ganglion was performed at one, three and six months. Nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase staining was used to identify NOS in the penile nerve fibers. The gene expression for growth factors and bNOS was investigated in corporal tissue by reverse transcriptase-polymerase chain reaction (RT-PCR) using specific oligonucleotide primers. One month after neurotomy, both unilateral and bilateral neurotomy groups showed a significant decrease in NOS-containing nerve fibers on the dorsal and intracavernosal nerves on the side of neurotomy, and a significantly lower mRNA expression of bNOS, IGF-I and TGF-beta 2. At three months, the number of NOS-containing nerve fibers in the unilateral neurotomy group increased only slightly but at six months those in the intracavernosal nerve increased in a significant amount (P < 0.0001), however mRNA expression of bNOS, IGF-I and TGF-beta 2 showed a significant increase as early as at three months. After bilateral neurotomy, the NOS-positive nerve fibers in the dorsal and intracavernosal nerve were significantly decreased at one month and remained so at six months; no erectile response could be elicited by pelvic ganglion stimulation. In the unilateral neurotomy group at six months, more NOS-positive neurons in the pelvic ganglia were found on the intact side than on the side of the neurotomy (P < 0.003), indicating that the regeneration derives from pelvic ganglion neurons on the intact side. Furthermore, electrostimulation in the unilateral neurotomy group revealed a greater maximal intracavernosal pressure and a shorter latency period at six months than at one month (P < 0.014, P < 0.001, respectively). These data suggest that IGF-I and TGF-beta 2 may play a key role in regeneration of NOS-containing nerve fibers in the dorsal and intracavernosal nerves after unilateral cavernous nerve injury.

Animals↗
PubMed1999

Effects of TNF-alpha and IL-1 beta on mucin, lysozyme, IL-6 and IL-8 in passage-2 normal human nasal epithelial cells.

Little is known about the regulatory effects of cytokines on various nasal secretions in normal human nasal epithelial cells. The aim of this study was to examine whether TNF-alpha, IL-1beta or their combination can increase the secretion of mucin as an indicator of mucous secretion, the secretion of lysozyme as an indicator of serous secretion and the secretion of IL-6 and IL-8 as important cytokines. In addition, we wanted to examine their message levels in normal human nasal epithelium. On day 12 of culture, passage-2 normal human nasal epithelial cells were treated with 10 ng/ml TNF-alpha, 10 ng/ml IL-1beta and combinations of both. Twenty-four hours later, the apical secretions were collected. A mixture of TNF-alpha and IL-1beta synergistically increased secretion of mucin, IL-6 and IL-8, but did not increase secretion of lysozyme. A combination of TNF-alpha and IL-1beta showed a questionable increase of MUC2 mRNA levels. TNF-alpha, IL-1beta and a combination of both all significantly increased MUC8 mRNA levels. Neither TNF-alpha, IL-1beta nor a combination of both increased MUC5AC, MUC5B and lysozyme mRNA levels. IL-1beta alone or a combination of TNF-alpha and IL-1beta comparably increased IL-6 and IL-8 mRNA levels slightly. In conclusion, a mixture of inflammatory mediators can synergistically increase secretion of mucin, IL-6 and IL-8 in human nasal epithelium. Accordingly, nasal secretions may be under the control of an inflammatory mediator network.

Cells, Cultured↗
PubMed1999

Regulation of mRNA export by nutritional status in fission yeast.

We have isolated a mutation in nup184(nup184-1) that is synthetically lethal with the mRNA export defective rae1-167 mutation in Schizosaccharomyces pombe. The consequence of the synthetic lethality is a defect in mRNA export. The predicted Nup184p is similar to Nup188p of Saccharomyces cerevisiae, and a Nup184p-GFP fusion localizes to the nuclear periphery in a punctate pattern. The Deltanup184 null mutant is viable and also is synthetically lethal with rae1-167. In a rae1(+) background, both the nup184-1 and Deltanup184 mutations confer sensitivity to growth in nutrient-rich medium (YES) that is accompanied by nuclear poly(A)+ RNA accumulation. Removal of the cAMP-dependent protein kinase, Pka1p, relieved the growth and mRNA export defects of nup184 mutants when grown in nutrient-rich medium. The activation of Pka1p is necessary, but not sufficient, to cause the severe poly(A)+ RNA export defects when nup184 mutant cells are incubated in YES, suggesting nutritional status can also regulate poly(A)+ RNA export. Our results suggest that the regulation of poly(A)+ RNA export by Pka1p kinase appears to be indirect, via a translation-dependent step, but post-translationally in response to YES.

Cell Nucleus↗
PubMed1999

Double-phase Tc-99m sestamibi scintimammography to assess angiogenesis and P-glycoprotein expression in patients with untreated breast cancer.

This study evaluated the relation of Tc-99m sestamibi (MIBI) uptake and washout in untreated breast cancer with immunohistochemically determined angiogenesis and P-glycoprotein expression. Thirty-one patients with untreated breast cancer were studied prospectively. Tc-99m MIBI scintigraphy and immunohistochemical analyses of angiogenesis and P-glycoprotein expression were used to evaluate surgically removed tumor tissues. Anterior and both lateral planar images were acquired 10 and 180 minutes after intravenous injection of 740 MBq (20 mCi) Tc-99m MIBI. The tumor-to-normal breast ratio (T:N) and washout index (early T:N - late T:N divided by early T:N) were calculated. A significant correlation was found between angiogenesis and T:N at early and late images. Pearson's correlation coefficients and probability values were r = 0.54, P = 0.002 at early images and r = 0.47, P = 0.008 at late images. The T:N of both early and late images were not different among different groups of P-glycoprotein expression (P = 0.367 and P = 0.113, respectively), although the washout index was significantly different among the groups (P = 0.001). A strong correlation was found between the washout index and P-glycoprotein expression (r = 0.67, P < 0.01). Double-phase scintimammography to assess the early tumoral uptake and washout of Tc-99m MIBI can be used as a simple functional test for in vivo imaging of tumoral angiogenesis and P-glycoprotein expression in patients with untreated breast cancer.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1999

Nocardioides nitrophenolicus sp. nov., a p-nitrophenol-degrading bacterium.

A p-nitrophenol-degrading bacterial strain was isolated from industrial wastewater. This strain (NSP41T) was identified as a member of the genus Nocardioides from chemotaxonomic characterizations and phylogenetic inference based on 16S rDNA sequence analysis. The G + C content is 71.4 mol%. The diamino acid in the cell-wall peptidoglycan is LL-diaminopimelic acid. The predominant menaquinone is MK-8(H4). The cellular fatty acid profile is similar to those of Nocardioides species. 16S rDNA sequence analysis show that strain NSP41T is the most related to Nocardioides simplex strains with a level of nucleotide similarity of 98.6%. The levels of 16S rDNA similarity between strain NSP41T and other Nocardioides species ranged from 93.8 to 95.1%. This organism is distinguishable from some other Nocardioides species as well as N. simplex strains by DNA-DNA relatedness data. This organism is different from N. simplex strains in some phenotypic characteristics. Therefore, on the basis of the data presented, a new species of the genus Nocardioides, Nocardioides nitrophenolicus, is proposed. The type strain of the new species is strain NSP41T (= KCTC 0457BPT).

Actinomycetales↗
PubMed1999

Classification of 'Nocardioides fulvus' IFO 14399 and Nocardioides sp. ATCC 39419 in Kribbella gen. nov., as Kribbella flavida sp. nov. and Kribbella sandramycini sp. nov.

By 16S rDNA sequence analysis, two strains identified previously as members of the genus Nocardioides, namely 'Nocardioides fulvus' IFO 14399 and Nocardioides sp. ATCC 39419, were found to form lines of descent distinct from the genus Nocardioides. Therefore, the two strains were studied taxonomically in detail by phenotypic, particularly chemotaxonomic, characterization, and by phylogenetic analysis including other related taxa. The genomic DNA G + C contents of 'N. fulvus' IFO 14399 and Nocardioides sp. ATCC 39419 are 70 and 68 mol%, respectively. The two strains contain LL-diaminopimelic acid as the diamino acid in their peptidoglycan, together with L-alanine at position 1 of the peptide subunit. The predominant menaquinone found in the two strains is MK-9(H4). The major cellular fatty acid found in the two strains is anteiso-C15:0' which is a minor component of members of the genus Nocardioides. The diagnostic polar lipid of the two strains is phosphatidylcholine. A phylogenetic tree was constructed which showed that the two strains from evolutionary lineages distinct from other LL-diaminopimelic-acid-containing taxa such as, for example, the genus Nocardioides. On the basis of our data, a new genus, Kribbella gen. nov., and two new species, Kribbella flavida gen. nov., sp. nov. and Kribbellla sandramycini gen. nov., sp. nov., are proposed. It is also proposed that the new genus be included in the family Nocardioidaceae.

Actinomycetales↗
PubMed1999

Chronological changes in incidences of polymorphic reticulosis in Korea and Japan.

Lethal midline granuloma (LMG) is a clinical term, which describes a group of diseases histologically comprising Wegener's granulomatosis, polymorphic reticulosis (PR), and malignant lymphoma of the ordinary type (ML). PR is a variant of ML, and is considered to be a type of NK/T cell lymphoma. Our previous study revealed the clustering of patients with PR in East Asia including China, Korea and Japan. However, the frequency rate of PR varied even among these countries, with that of Korea being approximately 5 times higher than that of Japan. In the present study, we examined the incidences of each type of LMG, especially PR, in Korea (Yonsei University) and Japan (59 university hospitals) over time. A total of 102 cases and 655 cases of LMG admitted to Yonsei University, Korea from 1977 to 1996 and 59 university hospitals in Japan between 1965 and 1996, respectively, were examined. The frequency rate of PR per 100,000 outpatients of ears, nose and throat (ENT) clinics in Korea decreased from 40 to 20 between the periods of 1977-1989 and 1990-1996. However, there were no significant changes in Japan during the period studied.

Adolescent↗
PubMed1999

Restoration of the mucous phenotype by retinoic acid in retinoid-deficient human bronchial cell cultures: changes in mucin gene expression.

Retinoid-deficient cultures of airway epithelial cells undergo squamous differentiation. Treatment of such cultures with retinoic acid (RA) leads to restoration of the mucous phenotype. The purpose of our study was to characterize the cellular and molecular changes following RA treatment of retinoid-deficient human tracheobronchial epithelial cell cultures. Of particular interest was to determine when during the conversion of the squamous to the mucous phenotype the mucin genes MUC2, MUC5AC, and MUC5B were expressed. We used cornifin alpha and secreted mucin as markers to monitor the squamous and mucous phenotypes, respectively. Our studies showed that the RA responsiveness of the cultures progressively decreased with protracted retinoid deficiency, requiring higher RA concentrations to restore the mucous phenotype. Within 12 h after the start of RA treatment, cornifin alpha expression decreased, signaling the beginning of a change in cellular phenotype. At 24 h after addition of RA to the cultures, a significant number of mucous cells appeared, and at 72 h mucin was secreted in measurable amounts. Induction of mucin gene expression occurred sequentially: MUC2, MUC5AC, and MUC5B mRNAs were upregulated at 24, 48, and 72 h, respectively. When cultures maintained in 10(-8) M RA were treated with 10(-6) M RA, MUC2 but not MUC5AC and MUC5B mRNA levels were upregulated within 6 h. Our study indicates that MUC2 mRNA is an early marker of mucous differentiation, whereas MUC5AC and MUC5B mRNAs are expressed during more advanced stages of mucous differentiation. Our studies further suggest that each of the mucin genes is regulated by distinct mechanisms.

Blotting, Northern↗
PubMed1999

Lysozyme expression during metaplastic squamous differentiation of retinoic acid-deficient human tracheobronchial epithelial cells.

We previously reported (Gray, T. E., K. Guzman, C. W. Davis, L. H. Abdullah, and P. Nettesheim. 1996. Mucociliary differentiation of serially passaged normal human tracheobronchial epithelial cells. Am. J. Respir. Cell Mol. Biol. 14:104-112) that retinoic acid (RA)-deprived cultures of normal human tracheobronchial epithelial (NHTBE) cells became squamous, failed to produce mucin, and instead secreted or released large amounts of lysozyme (LZ). The purpose of the studies reported here was to elucidate the relationship between RA deficiency-induced squamous differentiation and increased LZ, and to determine what mechanisms were involved. We found that intracellular LZ began to accumulate in RA-deficient NHTBE cultures early during squamous differentiation. Between Days 10 and 18 of culture, cellular LZ levels were more than 10 times higher in RA-deficient than in RA-sufficient cultures. On Day 12, large numbers of cells began to exfoliate in RA-deficient cultures and extracellular LZ appeared at the apical surface, presumably released from the exfoliated cells. Metabolic labeling studies showed that the rate of LZ synthesis was not increased in RA-deficient cultures over that in RA-sufficient cultures; however, intracellular LZ half-life was much longer in RA-deficient cultures. We concluded that the increased accumulation of both intra- and extracellular LZ in RA-deficient cultures was due to increased LZ stability and was not the result of increased LZ synthesis. When RA-deficient cultures were treated on Day 7 with 10(-6) M RA, intracellular LZ levels did not substantially decrease until 3 d later, coinciding with a marked increase in mucin secretion. LZ messenger RNA levels were unchanged at 24 h, but were modestly increased (rather than decreased) at all subsequent time points. We concluded that RA does not directly regulate LZ, and that the excessive accumulation of LZ in RA-deprived NHTBE cells is a consequence of vitamin A deficiency-induced abnormal differentiation.

Bronchi↗
PubMed1999

Calcification in chronic maxillary sinusitis: comparison of CT findings with histopathologic results.

BACKGROUND AND PURPOSE: It is important to differentiate fungal from nonfungal sinusitis in order to determine the optimal treatment for chronic sinusitis. The purpose of this study was to describe the CT findings of calcifications in chronic fungal and nonfungal maxillary sinusitis. METHODS: Five hundred ten patients with pathologically proved chronic maxillary sinusitis were studied with unenhanced CT before undergoing sinonasal surgery. In 36 patients, the CT scans were reviewed retrospectively to ascertain the shape and location of intrasinus calcifications. RESULTS: Calcifications were found in 20 (51%) of 39 patients with fungal sinusitis and in 16 (3%) of 471 patients with nonfungal sinusitis. Direct histopathologic correlation was performed in two of 16 patients with nonfungal sinusitis who had intrasinus calcification. The location of intrasinus calcification was central in 95% of the patients with fungal sinusitis and peripheral in 81% of those with nonfungal sinusitis. Although calcifications with a nodular or linear shape were seen in both fungal and nonfungal sinusitis, fine punctate type calcifications were seen only in those with fungal sinusitis (50%) and round or eggshell type calcifications only in those with nonfungal sinusitis (19%). CONCLUSION: Intrasinus calcifications are different in location and shape between fungal and nonfungal maxillary sinusitis. Although intrasinus calcification is uncommon in nonfungal sinusitis, the CT finding of intrasinus calcification may be helpful for differentiating fungal from nonfungal maxillary sinusitis.

Adolescent↗
PubMed1999

Development of a non-transformed human liver cell line with differentiated-hepatocyte and urea-synthetic functions: applicable for bioartificial liver.

There is a need to develop human hepatocyte cell lines which retain both replicating capacity and highly differentiated functions to facilitate the development of an efficient bioartificial liver. The present study was undertaken to differentiate, using sodium butyrate, the actively replicating immortalized human liver cell line. The effects of butyrate on cell growth and cell cycle were analyzed, and the albumin synthesis, cytochrome P450 and ammonia-detoxifying activity of the butyrate-treated cells were measured. Butyrate treatment resulted in G2/M arrest of the cell cycle and polygonal changes in the cell morphology. Neither the control nor the butyrate-treated cells showed transformed characteristics. Butyrate treatment increased the amount of albumin secretion, cytochrome P450 activity, and the urea production rate of the cells. The present study provides non-transformed human hepatocytes, which can replicate unlimitedly and then restore differentiated hepatocyte-specific functions by butyrate, and therefore, have applications for the development of an efficient bioartificial liver.

Albumins↗
PubMed1998

Identification and characterization of the antimicrobial peptide corresponding to C-terminal beta-sheet domain of tenecin 1, an antibacterial protein of larvae of Tenebrio molitor.

An active fragment was identified from tenecin 1, an antibacterial protein belonging to the insect defensin family, by synthesizing the peptides corresponding to the three regions of tenecin 1. Only the fragment corresponding to the C-terminal beta-sheet domain showed activity against fungi as well as Gram-positive and Gram-negative bacteria, whereas tenecin 1, the native protein, showed activity only against Gram-positive bacteria. CD spectra indicated that each fragment in a membrane-mimetic environment might adopt a secondary structure corresponding to its region in the protein. The leakage of dye from liposomes induced by this fragment suggested that this fragment acts on the membrane of pathogens as a primary mode of action. A comparison between the structure and the activity of each fragment indicated that a net positive charge was a prerequisite factor for activity. To the best of our knowledge this is the first report in which the fragment corresponding to the beta-sheet region in antibacterial proteins, which consists of alpha-helical and beta-sheet regions, has been identified as a primary active fragment.

Amino Acid Sequence↗
PubMed1998

Effect of salt hydrate pair on lipase-catalyzed regioselective monoacylation of sucrose.

Sucrose monoesters of a fatty acid were synthesized by using lipase in a solvent-free system. When lipase from Mucor miehei was used as a catalyst with capric acid as the donor and sugar as the acceptor, sucrose 6-monocaprate was predominantly produced in a yield of 25.3%. The yield of product was significantly increased by the direct addition of a suitable pair of solid salt hydrates to the reaction mixture to control the water activity (aw). Among the salt hydrate pairs investigated, the barium hydroxide, 8/1H2O pair resulted in the highest yield of the product. This salt addition method was also successfully employed for acylation of primary hydroxyl groups in various unprotected mono- and disaccharides such as glucose, galactose, fructose, trehalose, mannose, maltose, and lactose.

Acylation↗
PubMed1998

Sequence selectivity of DNA alkylation by adozelesin and carzelesin.

Adozelesin and carzelesin are synthetic analogues of the extremely potent antitumor antibiotic CC-1065, which alkylates N3 of adenine in a consensus sequence 5'-(A/T)(A/T)A* (A* is the site of alkylation). We have investigated the DNA sequence selectivity of adozelesin and carzelesin by thermally induced DNA strand cleavage assay using radiolabeled restriction DNA fragments. An analysis of alkylation patterns shows that the consensus sequences for carzelesin and adozelesin have been found to be 5'-(A/T)(A/T)A* and 5'-(A/T)(G/C)(A/T)A*. A new consensus sequence, 5'-(A/T)(A/T)CA*, has been observed to display an additional alkylation site for adozelesin but not for carzelesin. These results indicate that the pattern of sequence selectivity induced by carzelesin is similar but not identical to those induced by adozelesin.

Adenine↗
PubMed1998

The effect of botulinum toxin type A injection for intrinsic rhinitis.

Botulinum toxin type A (BTA) is known to inhibit the release of acetylcholine from cholinergic nerve endings. Owing to the characteristics of BTA, we thought that it could be used for the treatment of intrinsic rhinitis acting as an anticholinergic drug. In a double-blind placebo-controlled study four units of BTA were injected into the middle turbinate (two units) and inferior turbinate (two units) in each nasal cavity. Rhinorrhoea, nasal obstruction, and sneezing were recorded in a symptom diary on the basis of a scale of 5 and the number of paper tissues used per day was also recorded for 24 weeks. Rhinorrhoea was significantly diminished in severity (24.1-41.5 per cent reduction) and paper tissue use (54.3 per cent reduction) in the BTA group compared with the placebo group. This effect could be maintained for four weeks. Sneezing and nasal stuffiness were not affected by BTA. These results suggest that BTA can be used to treat rhinorrhoea in intrinsic rhinitis patients, however, the effective period is short.

Adult↗