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Biomedical subjects

J W Kim

Publications and source records attributed to J W Kim.

At least 145 records · Page 8Linked to original sources
PubMed2000

Kinetics and inhibition of cyclomaltodextrinase from alkalophilic Bacillus sp. I-5.

The cyclomaltodextrinase from alkalophilic Bacillus sp. I-5 (CDase I-5) was expressed in Escherichia coli and the purified enzyme was used for characterization of the enzyme action. The hydrolysis products were monitored by both HPLC and high-performance ion chromatography analysis that enable the kinetic analysis of the cyclomaltodextrin (CD)-degrading reaction. Analysis of the kinetics of cyclomaltodextrin hydrolysis by CDase I-5 indicated that ring-opening of the cyclomaltodextrin was the major limiting step and that CDase I-5 preferentially degraded the linear maltodextrin chain by removing the maltose unit. The substrate binding affinity of the enzyme was almost same for those of cyclomaltodextrins while the rate of ring-opening was the fastest for cyclomaltoheptaose. Acarbose and methyl 6-amino-6-deoxy-alpha-d-glucopyranoside were relatively strong competitive inhibitors with K(i) values of 1.24 x 10(-3) and 8.44 x 10(-1) mM, respectively. Both inhibitors are likely to inhibit the ring-opening step of the CD degradation reaction.

Acarbose↗
PubMed2000

Effects of nitric oxide synthesis inhibition on the Na,K-ATPase activity in the kidney.

The present study was aimed at investigating the role of endogenous nitric oxide (NO) in regulating Na,K-ATPase activity in the kidney. The expression of alpha-1 and beta-1 subunits; and the enzymatic activity of Na,K-ATPase were determined in the kidney of rats treated with an NO synthase inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME). Following the treatment with L-NAME in the drinking water for 4 weeks, Na,K-ATPase activity was increased while tissue nitrite/nitrate levels were decreased in the kidney. Supplementation with L-arginine prevented the L-NAME-induced changes. The expression of either alpha-1 or beta-1 subunit protein of Na,K-ATPase, assessed by Western blot analysis, was not affected by L-NAME-treatment. An acute in vitro treatment of the kidney with L-NAME also caused an increase of Na,K-ATPase activity; which was again prevented by cotreatment with L-arginine. On the contrary, treatment with sodium nitroprusside significantly decreased Na,K-ATPase activity. These results suggest that the endogenous NO plays a direct inhibitory role on Na,K-ATPase activity in the kidney.

Animals↗
PubMed2000

Isolation and characterization of beta-galactosidase from Lactobacillus crispatus.

beta-Galactosidase was isolated from the cell-free extracts of Lactobacillus crispatus strain ATCC 33820 and the effects of temperature, pH, sugars and monovalent and divalent cations on the activity of the enzyme were examined. L. crispatus produced the maximum amount of enzyme when grown in MRS medium containing galactose (as carbon source) at 37 degrees C and pH 6.5 for 2 d, addition of glucose repressing enzyme production. Addition of lactose to the growth medium containing galactose inhibited the enzyme synthesis. The enzyme was active between 20 and 60 degrees C and in the pH range of 4-9. However, the optimum enzyme activity was at 45 degrees C and pH 6.5. The enzyme was stable up to 45 degrees C when incubated at various temperatures for 15 min at pH 6.5. When the enzyme was exposed to various pH values at 45 degrees C for 1 h, it retained the original activity over the pH range of 6.0-7.0. Presence of divalent cations, such as Fe2+ and Mn2+, in the reaction mixture increased enzyme activity, whereas Zn2+ was inhibitory. The Km was 1.16 mmol/L for 2-nitrophenyl-beta-D-galactopyranose and 14.2 mmol/L for lactose.

Animals↗
PubMed2000

Characterization of chromosomal breakpoints in an ALL patient using cross-species color banding.

Cross-species color-banded karyotype (Rx-FISH) results were compared with those of conventional G-banded metaphases from the same sample. Breakpoints and karyotype were confirmed as 46,XX,t(8;22)(q24;q11), der(9)t(1;9)(q21;p13) through the novel technology of cross-species color banding in an acute leukemic patient (ALL, L3); the karyotype was 46,XX,t(8;22)(q24;q11),der(9)t(1;9)(q25;p24) by conventional G-banding.

Adult↗
PubMed2000

Melanocytic nevus with pregnancy-related changes in size accompanied by apoptosis of nevus cells: a case report.

Melanocytic nevi are commonly believed to undergo changes during pregnancy. This is probably related to hormonal influences; however, few studies have been able to prove it. We observed a case of a benign melanocytic nevus, which showed significant enlargement during pregnancy and immediate postpartum regression associated with increased apoptosis of nevus cells. Estrogen and progesterone receptors were not found in our case, although the clinical course still suggested a close association with hormonal influences.

Adult↗
PubMed2000

Molecular cloning, distribution and pharmacological characterization of a novel gonadotropin-releasing hormone ([Trp8] GnRH) in frog brain.

To date nine structural variants of GnRH have been identified in vertebrates and two additional forms have been isolated from a tunicate. In amphibians only mammalian GnRH ([Arg8] GnRH) and type II GnRH (chicken GnRH II, [His5, Trp7, Tyr8] GnRH) have been identified. In the present study, a full-length cDNA encoding a novel type of GnRH was isolated from pituitary of Rana dybowskii. The GnRH gene encodes a GnRH peptide ([Trp8] GnRH) in which tryptophan is substituted for arginine of mammalian GnRH Northern blot analysis revealed the presence of a single 500 bp transcript for the [Trp8] GnRH precursor in forebrain but its absence in testis, ovary, kidney and liver. Restriction digests of genomic DNA demonstrated a single copy of the gene. The [Trp8] GnRH immunoreactive cells were identified in the preoptic area of the frog brain. Synthetic [Trp8] GnRH was tested for its ability to stimulate inositol phosphate production by COS-1 cells transfected with the cloned Xenopus pituitary GnRH receptor and the cloned human GnRH receptor. [Trp8] GnRH had a potency of about 60% compared with mammalian GnRH ([Arg8] GnRH) for the Xenopus receptor, whereas the potency of [Trp8] GnRH was approximately 5% compared with mammalian GnRH for the human receptor. Both mammalian GnRH and [Trp8] GnRH were 1000-fold less potent than type II GnRH for the Xenopus GnRH receptor. The similar potency of [Arg8] GnRH and the novel [Trp8] GnRH for the Xenopus pituitary receptor indicates that, unlike the human receptor, the Xenopus receptor does not discriminate between these amino acids in position eight thereby allowing substitution of the arginine in the mammalian GnRH.

Amino Acid Sequence↗
PubMed2000

Effects of substance P and vasoactive intestinal peptide on interferon-gamma and interleukin-4 production in severe atopic dermatitis.

BACKGROUND: Recent studies have demonstrated that two T cell-derived lymphokines, interferon-gamma (IFN-gamma) and interleukin-4 (IL-4), play a crucial role in the pathogenesis of atopic dermatitis (AD). It is known that neuropeptides, such as substance P (SP) and vasoactive intestinal peptide (VIP), have various immunomodulatory effects. Elevated levels of these neuropeptides and increased staining of SP positive nerve fibers have been reported in AD patients. OBJECTIVE: The study was designed to examine the effects of SP and VIP on the production of IFN-gamma and IL-4. The aim of the study was to establish whether these neuropeptides acted to affect cytokine release in the peripheral blood mononuclear cells (PBMCs) of AD patients. METHODS: The effects of SP and VIP on the production of IFN-gamma and IL-4 in phytohemagglutinin stimulated PBMC cultures over a 48-hour period were analyzed by enzyme-linked immunosorbent assay in 15 AD patients. Non-atopic individuals were used as a control group. RESULTS: Base cytokine profiles of AD patients showed significantly decreased IFN-gamma and increased IL-4 when weighed against non-atopic controls. Compared with controls, SP had a significant percentage enhancing effect on both IFN-gamma and IL-4 production at concentrations of 10(-8) M and 10(-6) M, however, this IFN-gamma up-regulatory effect of SP was reversed by spantide, a SP antagonist. The ratios of IFN-gamma: IL-4 production were significantly elevated in the SP treated AD group. Although VIP had no specific noticeable effects on the IFN-gamma and IL-4 production. CONCLUSIONS: Our data may suggest that SP has an influence on the immunomodulation of AD patient by regulating IFN-gamma production, either directly or indirectly. Vasoactive intestinal peptide, on the other hand, has no modulatory effects on the cytokine production of AD patients.

Adolescent↗
PubMed2000

Spontaneous expression of mRNA for IL-10, GM-CSF, TGF-beta, TGF-alpha, and IL-6 in peripheral blood mononuclear cells from atopic dermatitis.

BACKGROUND: Monocytes and T helper cells play major roles in the immunologic dysfunction of atopic dermatitis (AD). There have been many studies on the cytokine pattern to evaluate abnormalities of immune cells in AD, but the results were conflicting and most of these previous reports were performed with various mitogen-stimulation. OBJECTIVE: The purpose was to investigate de novo cytokine pattern in AD peripheral blood mononuclear cells (PBMC). We focused on the expression of cytokines that have effects on monocytes and T cells. METHODS: We measured mRNA expression of IL-10, GM-CSF, TGF-beta, TNF-alpha, and IL-6 in freshly isolated PBMC with semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR). The intensity of cytokine cDNA were normalized to that of beta-actin product as a standard marker. RESULTS: Interleukin-10 mRNA expression was significantly enhanced in AD compared with control subjects (P < .05). Spontaneous mRNA expression of TGF-beta and TNF-alpha was significantly lower in AD patients (P < .01). The level of GM-CSF mRNA expression was heterogenous and spontaneous mRNA expression was slightly increased in AD although the difference didn't reach the statistical significance. Interleukin-6 mRNA was not detected in most of AD and controls. CONCLUSION: Our data could represent in vivo cytokine expression state associated with monocytes and other immune cells. Increased expression of IL-10 and GM-CSF may be associated with monocyte dysfunction in AD although increase in the expression of GM-CSF mRNA was not statistically significant. Inhibitory effect of increased IL-10 was suggested on decreased expression of TNF-alpha mRNA. The role of TGF-beta in AD remains to be seen.

Adolescent↗
PubMed2000

Identification and sequencing of pineal-specific enhancing region in the mouse tryptophan hydroxylase promoter.

Pineal-specific expression of the tryptophan hydroxylase (TPH) gene has been demonstrated by a number of studies. However, little is known about the regulatory mechanism for pineal-specific expression of the TPH gene. To identify the cis-acting region responsible for pineal-specific expression of the TPH gene, we investigated a 6.1-kb 5'-flanking region of the mouse TPH gene using an immortalized pineal cell line (PGT-beta) derived from transgenic mice. By deletion analysis, it was demonstrated that the pineal-specific enhancing region resides approximately between -6.1 and -4.7 kb upstream from the transcription initiation site of the mouse TPH gene. Additionally, nucleotide sequence analysis of this region showed that the (AC/TG)22 repetitive sequence is located approximately -5.78 kb upstream of the mouse TPH gene, and several known tissue-specific cis-acting elements, such as Pit-1 and the pituitary specific element (PSE), have also been identified in the region. We believe that the analysis of the sequence and several cis-acting elements in the pineal-specific enhancing region of the mouse TPH promoter would enhance our understanding of the precise mechanism of pineal-specific expression.

Animals↗
PubMed2000

AAC-11 overexpression induces invasion and protects cervical cancer cells from apoptosis.

To identify the genes involved in cervical carcinogenesis, we applied the mRNA differential display (DD) method to analyze normal cervical tissue, cervical cancer, metastatic lymph node, and cervical cancer cell line. We cloned a 491-bp cDNA fragment, CC231, which was present in metastatic tissue and cervical cancer cell line, but absent in normal cervical and cervical cancer tissues. The 491 bp cDNA fragment has 98% homology to the previously published sequence, AAC-11 (antiapoptosis clone 11). The levels of AAC-11 mRNA expressions in nine normal cervical and nine primary cervical cancer tissues were low. Its expression was higher in three metastatic tissues and five cervical cancer cell lines (HeLa, CaSki, SiHa, CUMC-3, and CUMC-6). Invasion of matrigel and adhesion to laminin by AAC-11 transfected CUMC-6 cells were increased by approximately 2-fold and 4-fold, respectively. Northern blot analysis showed that matrix metalloproteinase (MMP)-2 and membrane type 1 MMP (MT1-MMP) genes were found to be expressed in high levels in AAC-11-transfected cancer cells. But MMP-2 and MT1-MMP were not expressed in cells transfected with vector alone or wild-type cells. AAC-11-transfected cells expressed an elevated level of MMP-2 protein as assessed by immunoblotting. On the contrary, tissue inhibitor of MMP (TIMP-2) expression was detectable in cells transfected with vector alone or wild-type cells, respectively. Its expression was undetectable in AAC-11 transfected cells. In cervical cancer cells transfected with AAC-11, the expression of beta-catenin was up-regulated. These suggest that overexpressions of MMP-2 and MT1-MMP, loss of TIMP-2 expression, and up-regulation of beta-catenin by AAC-11 transfection may contribute to the development of cervical cancer invasion. AAC-11 gene transfection increased cervical cancer cell colonization. The effect of AAC-11 on cultured cervical cancer cells was associated with antiapoptotic process. Approximately 50% of the AAC-11 transfected cells in serum-free medium died after 2 weeks, compared to 1 week for vector alone or wild-type cells. These results suggest that AAC-11 may serve as a candidate metastasis-related and apoptosis-inhibiting gene in human cervical cancer.

Apoptosis↗
PubMed2000

Minor cutaneous features of atopic dermatitis in South Korea.

BACKGROUND: Minor cutaneous features are important in atopic dermatitis (AD) because they are related to the ethnic or genetic background and to the etiopathogenesis of the disease other than atopic allergy. In addition, they can be used as auxiliary diagnostic criteria in patients with uncertain major features. It is our experience that our AD patients have characteristic features that have not been described previously in the literature. METHODS: AD patients (n = 130) and control subjects (n = 198) were examined for the 32 conventional and seven additional minor features (sandpaper-like skin lesions on elbow/knee/lateral malleolus, hangnail, ventral wrist dermatitis, itchy hyperkeratotic papules on the dorsum of the hands, oily skin, fissured heel, and palmar erythema). The frequency of each feature was compared between AD patients and controls. The diagnostic significance of these minor features was analyzed separately in the childhood and adolescent-adult AD groups, and the age-related changes were documented. RESULTS: The seven additional features were significant for the diagnosis of AD in South Korean patients. Many of the other conventional minor features were also significant. Nine features were of diagnostic importance only in the adolescent-adult AD group, and three features were characteristic only in the childhood AD group. CONCLUSIONS: Our data suggest that ethnic backgrounds influence the phenotype of AD and that an additional seven features need to be examined to confirm the ethnic effect. As the general clinical presentation of AD is dependent upon age, the frequency of minor features varied in the different age groups.

Adolescent↗
PubMed2000

Clinical significance of early diastolic notch depth: uterine artery Doppler velocimetry in the third trimester.

OBJECTIVE: Our purpose was to evaluate the usefulness of early diastolic notch depth in predicting adverse perinatal outcome. STUDY DESIGN: Uterine artery Doppler velocimetry is widely applied in predicting pregnancy outcomes. Recent studies of uterine artery early diastolic notch have demonstrated its usefulness as a marker for fetal well-being. The early diastolic notch represents the reflected blood flow of uteroplacental circulation. This study was carried out under the hypothesis that when early diastolic notch is present evaluating its depth plays a significant role in predicting poor pregnancy outcomes. Its ability to predict adverse perinatal outcomes was evaluated in 198 pregnant women with early diastolic notch after 28 weeks' gestation. RESULTS: The incidence of adverse perinatal outcome (5-minute Apgar score <7, cesarean delivery because of fetal distress, admission to neonatal intensive care unit, fetal growth restriction, or perinatal death) was 90.5% when the notch index was </=0.70. When the notch index range was 0.70 to 0.79, 0.80 to 0.89, and >/=0.90, the respective incidences were 72.3%, 46. 9%, and 28.1%. CONCLUSION: This study suggests that evaluating notch depth in the presence of early diastolic notch on uterine artery velocimetry during the third trimester would be a useful method for predicting adverse perinatal outcomes.

Apgar Score↗