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Biomedical subjects

H Ryu

Publications and source records attributed to H Ryu.

At least 19 recordsLinked to original sources
PubMed2001

Korean American health insurance and health services utilization.

The purpose of this ethnic group study was to describe the unique pattern of Korean Americans, as compared with the aggregate of Asian Americans, for: (a) the predisposing, enabling, and need factors for health service utilization, focusing specifically on the role of health insurance coverage; and (b) predictors of health insurance coverage. Using the behavioral model for health service utilization, data were selected from the 1992 National Health Insurance Survey (NHIS, 1994) for Korean Americans (n = 345) and Asian Americans (n = 3,059). Results differed between the Korean American group and the Asian American group. Health insurance coverage was the strongest predictor of Korean American utilization, and need factors lacked significance, suggesting that uninsured Korean Americans have less access regardless of need. For the aggregate Asian American group, need factors tempered the influence of health insurance on utilization. Results of this type of study may be helpful for designing and implementing health care services tailored for specific ethnic at-risk markets.

Adolescent↗
PubMed2001

Abnormal exploratory eye movements in schizophrenic patients vs healthy subjects.

OBJECTIVE: We examined previously described exploratory eye movements abnormalities as biologic markers in schizophrenic patients in comparison with age-matched healthy subjects. MATERIAL AND METHODS: Using an eye-mark recorder, eye movements were analysed for mean gazing time, total number of gazing points, mean eye scanning length, total eye scanning length, and total gazing times as subjects viewed six simple pictures in preparation for copying them. RESULTS: In-patients, and to a lesser extent, out-patients, with schizophrenia showed a longer gazing time, fewer gazing points, a shorter mean and total eye scanning length. and longer gazing time than healthy subjects. In schizophrenic patients. negative symptom scores were positively correlated with mean gazing time (r = 0.33), and negatively correlated with the total number of gazing points (r = -0.29) as well as, the mean (r = -0.40) and total scanning length (r = -0.46). CONCLUSION: Exploratory eye movements are a biologic marker useful for evaluation of schizophrenia.

Adult↗
PubMed2001

Cnidicin, a coumarin, from the root of Angelica koreana, inhibits the degranulation of mast cell and the NO generation in RAW 264.7 cells.

Cnidicin (1) and five related coumarins were isolated from the root extract of Angelica koreana (Umbelliferae) as active principles responsible for the inhibitory effect on the degranulation process of cultured mast cells. Cnidicin (1) demonstrated a significant inhibition upon the release of beta-hexosaminidase from the cultured RBL-2H3 cells in a dose dependent manner (IC50 value, 25 microM) and upon the nitric oxide production from the activated RAW264.7 cells (IC50 value, 7.5 microM). In agreement with this, cnidicin inhibited the expression of nitric oxide synthase in RAW264.7 cells.

Animals↗
PubMed2001

Escherichia coli strain RDEC-1 AF/R1 endogenous fimbrial glycoconjugate receptor molecules in rabbit small intestine.

Escherichia coli strain RDEC-1 causes a diarrheagenic infection in rabbits with AF/R1 fimbriae, which have been identified as an important colonization factor in RDEC-1 adherence leading to disease. The AF/R1-mediated RDEC-1 adherence model has been used as a model systems for E. coli diarrheal diseases. In this study, RDEC-1 adhered specifically to small intestinal brush borders, with both sialic acid and beta-galactosyl residues apparently involved. The AF/R1-mediated adherence activity of [(14)C]-labeled RDEC-1 was analyzed quantitatively by using 24-well plates coated with purified brush borders and purified microvilli. Two microvillus membrane proteins (130 and 140 kDa) were individually isolated, and chicken antibody raised to each protein inhibited bacterial adherence. These same two proteins, previously shown to be recognized by AF/R1, were individually digested with trypsin, and the amino acid sequences of peptides were determined by reversed-phase capillary liquid chromatography-mass spectrometry tandem mass spectrometry (LC-MS). This LC-MS analysis indicated that these proteins are subunits of the rabbit sucrase-isomaltase protein (SI) complex. Guinea pig serum raised to purified rabbit SI complex inhibited bacterial adherence to microvilli. Additionally, as determined by high-performance thin-layer chromatography and autoradiography, RDEC-1 adhered selectively, via AF/R1 fimbriae, to a glycolipid tentatively identified as galactosylceramide (Gal beta 1-1Cer) in the lipid extract of rabbit small intestinal brush borders. RDEC-1 adherence to Gal beta 1-1Cer was partially inhibited in the presence of galactose. These combined results indicate that the endogenous receptor molecule for AF/R1 fimbriae of RDEC-1 is each individual component of the SI complex, although binding to glycolipid may be responsible for an additional adherence mechanism.

Amino Acid Sequence↗
PubMed2001

Effects of emitted Qi on in vitro natural killer cell cytotoxic activity.

The present study investigated the effects of Korean Qi-therapy, ChunSoo Energy Healing, on natural killer (NK) cell cytotoxicity in vitro depending on Qi-treatment time and the types of cells treated. NK cell cytotoxicity was assayed by measuring LDH release from tumor target cells (K562 cell lines). NK activity was significantly increased by emitted-Qi treatment of 30 sec duration. Three and 5 minutes of Qi projection created the greatest increase in NK cell activity when mixtures of NK cells and K562 cells were treated (1.81 and 2.12 fold for 4 hr culture; 1.54 and 1.36 for 16 hr culture, respectively). NK cell activity increased significantly in Qi-treated K562 cells alone (1.13 fold, p<0.05) compared to control. These results are consistent with in vivo Qi-therapy on humans and suggests that emitted-Qi has an acute stimulatory effect on NK cell activity. This study provides direct scientific support that Qi as such may positively affect human cellular immunity.

Cells, Cultured↗
PubMed2001

Qi therapy as an intervention to reduce chronic pain and to enhance mood in elderly subjects: a pilot study.

Qi therapy (or external Qi) is an oriental complementary therapy preventing, curing disease and strengthens health and improving the human potentiality through regulation of body. It is increasingly being used to improve the quality of life, but there is little direct evidence of its efficacy. This study assessed the effects of Qi therapy (QT) on reducing pain and enhancing mood states in elderly subjects with chronic pain. We studied 40 elderly participants with chronic pain, who were randomly allocated to receive QT (n=20) or standard care (n=20). The experimental group receives Qi therapy twice a week for 2 weeks (total 4 times), and control group received general care at the same time and the same amount of duration. We measured pain level and Profile of Mood State (POMS) to explore participants' response to Qi therapy. There was a significant reduction in pain (p<0.0001) after QT and an improved positive mood state (p<0.0001). These findings suggest that Qi therapy may have a role in helping the elderly to cope with their pain and mood disturbances.

Affect↗
PubMed2001

Sequence-selective DNA binding drugs mithramycin A and chromomycin A3 are potent inhibitors of neuronal apoptosis induced by oxidative stress and DNA damage in cortical neurons.

Global inhibitors of RNA or protein synthesis such as actinomycin D or cycloheximide abrogate neuronal apoptosis induced by numerous pathological stimuli in vitro and in vivo. The clinical application of actinomycin D or cycloheximide to human neurological disease has been limited by the toxicities of these agents. To overcome these toxicities, strategies must be developed to inhibit selectively the expression of deleterious proapoptotic proteins, while leaving the expression of antiapoptotic, proregeneration, and other critical homeostatic proteins unperturbed. Mithramycin A (trade name Plicamycin) is an aureolic acid antibiotic that has been used in humans to treat hypercalcemia and several types of cancers. This class of agents is believed to act, in part, by selectively inhibiting gene expression by displacing transcriptional activators that bind to G-C-rich regions of promoters. Here we demonstrate that mithramycin A and its structural analog chromomycin A3 are potent inhibitors of neuronal apoptosis induced by glutathione depletion-induced oxidative stress or the DNA-damaging agent camptothecin. We correlate the protective effects of mithramycin A with its ability to inhibit enhanced DNA binding of the transcription factors Sp1 and Sp3 to their cognate "G-C" box induced by oxidative stress or DNA damage. The protective effects of mithramycin A cannot be attributed to global inhibition of protein synthesis. Together, these results suggest that mithramycin A and its structural analogs may be effective agents for the treatment of neurological diseases associated with aberrant activation of apoptosis and highlight the potential use of sequence-selective DNA-binding drugs as neurological therapeutics.

Animals↗
PubMed2000

Regulation of neutrophil adhesion by pituitary growth hormone accompanies tyrosine phosphorylation of Jak2, p125FAK, and paxillin.

Neutrophil adhesion is fundamentally important during the onset of inflammatory responses. The adhesion signaling pathways control neutrophil arrest and extravasation and influence neutrophil shape and function at sites of inflammation. In the present study the intracellular signaling pathways for the adhesion of human neutrophils by pituitary growth hormone (GH) were examined. Pituitary GH triggered the tyrosine phosphorylation of Janus kinase 2 (Jak2) and STAT3 in neutrophils. In addition, pituitary GH treatment resulted in the morphological changes and the tyrosine phosphorylation of focal adhesion kinase (p125FAK) and paxillin. Preincubation with genistein, a tyrosine kinase inhibitor, blocked the GH-stimulated adhesion and Jak2, STAT3, p125FAK, and paxillin phosphorylation. Confocal microscopy revealed that pituitary GH stimulates the focal localization of p125FAK, paxillin, phosphotyrosine, and filamentous actin filament into the membrane rufflings and uropods of human neutrophils. Immunoprecipitation experiments revealed a physical association of Jak2 with p125FAK via STAT3 in vivo. Also an in vitro kinase assay showed an augmentation of p125FAK autophosphorylation as a result of pituitary GH treatment. These results suggest that pituitary GH modulates neutrophil adhesion through tyrosine phosphorylation of Jak2, p125FAK, and paxillin and actin polymerization.

Actins↗
PubMed2000

Modified partial hyperfractionation in radiotherapy for bulky uterine cervical cancer: reduction of overall treatment time.

PURPOSE: The purpose of this study was to assess the feasibility and toxicity of modified fractionation of external beam radiation with the intention of reducing the overall treatment time (OT) by 1 week in cervical cancer. METHODS AND MATERIALS: Thirty-one patients (Group 1, n = 31) with bulky cervical cancer (>/= 4 cm with Stage II and III, >/= 5 cm with Stage IB2) were entered into the twice a day (b.i. d.) protocol (18 Gy/10 fx in 2 weeks followed by 18 Gy/12 fx, b.i.d. in 6 days, then midline block at 36 Gy with 45 Gy to the whole pelvis and 51-59 Gy to the parametrium). These patients underwent high-dose-rate brachytherapy with 4 Gy/fx x 7 to point A, biweekly. During the same period, patients with non-bulky tumors (Group 2, n = 31) received conventional treatment and similar brachytherapy. RESULTS: The OT of Group 1 was 7 weeks or less in 61.3%, 7.1-8 weeks in 29%, and more than 8 weeks in 9.7% (19.4%, 51.6%, and 29% in Group 2, respectively, p = 0.003). Incidences of acute complications and treatment breaks were similar in both groups. Late complication (rectal bleeding) occurred only in Group 1 (13%, 4/31), but was self-limited. Locoregional failures occurred within 2 years after completion of radiation therapy in both groups (16% and 13% in Group 1 and 2, respectively, with minimum and median follow-ups of 2 years and 34 months). CONCLUSION: Partial hyperfractionation on the third week of radiation permitted patients to finish their treatment with shorter OT without excessive acute complications and with acceptable grade 2 late rectal bleeding complications. This treatment scheme may be an effective method for the improvement of local control of bulky cervical cancer.

Adult↗
PubMed2000

Modulation of neuroendocrinological function by psychosomatic training: acute effect of ChunDoSunBup Qi-training on growth hormone, insulin-like growth factor (IGF)-I, and insulin-like growth factor binding protein (IGFBP)-3 in men.

The neuroendocrine system is regarded as the major link between the psychological state and the immune system in man. The present study was undertaken to examine the acute effect of ChunDoSunBup Qi-training, a traditional psychosomatic training, on the plasma level of growth hormone (GH), insulin-like growth factor (IGF)-I and insulin like growth factor binding protein (IGFBP)-3 in young men. To characterize the plasma level of hormones and the pattern of IGFBP-3 at pre- (-10 min), mid-time (40 min), and immediately after (post-time, +10 min) Qi-training, radioimmunoassay (RIA) and western ligand blot (WLB) analysis were used. The plasma level of GH at the mid-time was significantly increased (P<0.05) compared to the level at pre-time of Qi-training. The plasma level of IGF-I was also increased at mid-time (P<0.05) and immediately after Qi-training. There was a significant correlation between the levels of GH and IGF-I immediately after Qi-training (r=0.69, P<0.01). In this study, the change of IGFBP-3 among the several IGFBPs was determined. There was a relative shift in IGFBP-3 for the 43-kDa fraction during mid-time of Qi-training (P<0.05). These results suggest that Qi-training influences the growth hormone, IGF-I and IGFBP-3 status via brain-target organ axis in men.

Adult↗
PubMed2000

Effect of Qi-training on blood pressure, heart rate and respiration rate.

To examine the physiological effects of Korean traditional Qi-training, we investigated the changes in blood pressure, heart and respiratory rates before, during and after ChunDoSunBup (CDSB) Qi-training. Twelve normal healthy CDSB Qi-trainees (19-37 years old; trained for 1.3 +/- 0.2 years; 9 men and 3 women) volunteered to participate in this study. Heart rate, respiratory rate, systolic blood pressure and rate-pressure product were significantly decreased during Qi-training. From these results, we suggest that CDSB Qi-training has physiological effects that indicate stabilization of cardiovascular system.

Adult↗
PubMed2000

Usefulness of high-resolution magnetic resonance cisternography in patients with hemifacial spasm.

To analyse the usefulness of preoperative magnetic resonance (MR) cisternography in patients with hemifacial spasm (HFS), MR observations were compared with surgical findings. High-definition images were obtained using MR cisternography which employed a long echo train length, fast spin-echo sequence, which revealed both nerves and blood vessels without any contrast media. In 35 HFS patients, certified radiologists examined the presence of vascular compression of the facial nerve and identified the offending vessels. MR cisternography depicted neurovascular compression in 31 patients (sensitivity 88.6%) and correctly determined the offending vessels in 28 patients. In 4 patients, MR cisternography revealed the presence of the vessel near the facial nerve, but the radiologist evaluated the compression as questionable (false-negative rate 11.4%). Even in these patients, MR cisternography revealed the precise anatomy of cerebellopontine (CP) cistern. High-resolution MR cisternography is useful in identifying the vessels and nerve bundles in the CP cistern, and in so doing can provide surgeons with valuable information regarding neurovascular decompression for HFS.

Cerebellopontine Angle↗
PubMed2000

A simple technique for neurovascular decompression of the cranial nerves.

Various synthetic materials and plastic adhesives are used for neurovascular decompression, but they may have some adverse effects on nervous tissue. We used fibrin glue alone for neurovascular decompression and obtained excellent results without complications or recurrence, compared with the previous technique with a prosthesis or plastic adhesive.

Cerebellum↗
PubMed1999

Protection from oxidative stress-induced apoptosis in cortical neuronal cultures by iron chelators is associated with enhanced DNA binding of hypoxia-inducible factor-1 and ATF-1/CREB and increased expression of glycolytic enzymes, p21(waf1/cip1), and erythropoietin.

Iron chelators are pluripotent neuronal antiapoptotic agents that have been shown to enhance metabolic recovery in cerebral ischemia models. The precise mechanism(s) by which these agents exert their effects remains unclear. Recent studies have demonstrated that iron chelators activate a hypoxia signal transduction pathway in non-neuronal cells that culminates in the stabilization of the transcriptional activator hypoxia-inducible factor-1 (HIF-1) and increased expression of gene products that mediate hypoxic adaptation. We examined the hypothesis that iron chelators prevent oxidative stress-induced death in cortical neuronal cultures by inducing expression of HIF-1 and its target genes. We report that the structurally distinct iron chelators deferoxamine mesylate and mimosine prevent apoptosis induced by glutathione depletion and oxidative stress in embryonic cortical neuronal cultures. The protective effects of iron chelators are correlated with their ability to enhance DNA binding of HIF-1 and activating transcription factor 1(ATF-1)/cAMP response element-binding protein (CREB) to the hypoxia response element in cortical cultures and the H19-7 hippocampal neuronal cell line. We show that mRNA, protein, and/or activity levels for genes whose expression is known to be regulated by HIF-1, including glycolytic enzymes, p21(waf1/cip1), and erythropoietin, are increased in cortical neuronal cultures in response to iron chelator treatment. Finally, we demonstrate that cobalt chloride, which also activates HIF-1 and ATF-1/CREB in cortical cultures, also prevents oxidative stress-induced death in these cells. Altogether, these results suggest that iron chelators exert their neuroprotective effects, in part, by activating a signal transduction pathway leading to increased expression of genes known to compensate for hypoxic or oxidative stress.

Activating Transcription Factor 1↗
PubMed1999

Neurovascular compression syndrome of the eighth cranial nerve. Can the site of compression explain the symptoms?

Considerable skepticism still exists concerning the concept of neurovascular compression (NVC) syndromes of the eighth cranial nerve (8th N). If such syndromes exist, the sites of compression of the nerve must explain the symptoms encountered. We recorded compound action potentials of the cochlear nerve (CCAPs) during neurovascular decompression (NVD) to examine the topography of the three components of the 8th N. The sites of compression of the 8th N in cases of NVC syndrome confirmed at surgery were superimposed on the topography of the CN and vestibular nerve (VN) in order to determine the relationship between the sites of compression and the symptoms. CCAPs were clearly and consistently recorded on the caudal surface of the 8th N along the midline. In patients with vertigo and tinnitus there was vascular compression of the rostroventral (VN) and caudal surface (CN) of the nerve, respectively. In patients with both vertigo and tinnitus, there was compression of both VN and CN. Our findings clearly demonstrate that the symptoms of NVC of the 8th N depend on the part of the nerve that is compressed by blood vessels, and they support the concept of NVC syndrome of the 8th N.

Action Potentials↗
PubMed1999

Aneurysm of persistent primitive hypoglossal artery.

A patient with a ruptured intracranial aneurysm of the right persistent primitive hypoglossal artery is described. Clipping of the aneurysmal neck was achieved by a far lateral approach together with drilling of the jugular tubercle, and it was concluded that this approach should be followed for safe and complete clipping.

Aneurysm, Ruptured↗
PubMed1999

Eighteen-year survival of a patient with malignant pleomorphic xanthoastrocytoma associated with von Recklinghausen neurofibromatosis.

The authors report the first adult case of pleomorphic xanthoastrocytoma associated with neurofibromatosis-1. A 40-year-old man with history of neurofibromatosis-1 underwent total removal of a right temporo-parietal superficial glioma followed by radiation therapy. Eighteen years after surgery, the patient remained well with no tumour recurrence, which prompted review of the surgical material. The diagnosis of pleomorphic xanthoastrocytoma was then made though the tumour exhibited malignant features histologically, with marked necrosis. This extremely good clinical outcome suggest that some astrocytoma tumours in patients with neurofibromatosis might be associated with a favourable prognosis.

Adenoma, Pleomorphic↗