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Biomedical subjects

J H Ryu

Publications and source records attributed to J H Ryu.

At least 37 records · Page 2Linked to original sources
PubMed2001

Dietary conjugated linoleic acid (CLA) induces apoptosis of colonic mucosa in 1,2-dimethylhydrazine-treated rats: a possible mechanism of the anticarcinogenic effect by CLA.

One of the objectives of the present study was to investigate whether 1 % conjugated linoleic acid (CLA) in the diet reduced tumour incidence in the colon of 1,2-dimethylhydrazine (DMH)-treated rats. Colon cancer was induced by injecting 6-week-old, male, Sprague-Dawley rats with 15 mg/kg DMH twice per week for 6 weeks. They were fed either 1 % CLA or a control diet ad libitum for 30 weeks. Dietary CLA significantly decreased colon tumour incidence (P<0.05). Our second objective was to investigate whether apoptosis in the colon mucosa of DMH-treated rats was affected by the amount of dietary CLA and whether the changes in apoptosis were related to those in fatty acid-responsive biomarkers. For this purpose, rats were killed after being fed a diet containing 0 %, 0.5 %, 1 % or 1.5 % CLA for 14 weeks. CLA was undetected in the mucosa of rats fed the 0 % CLA diet and increased to 5.9 mg/g phospholipid in rats fed the 0.5 % diet. The apoptotic index estimated by the terminal deoxynucleotidyl transferase-mediated dUTP nick and labelling technique was increased by 251 % and the 1,2-diacylglycerol content was decreased by 57 % in rats fed 0.5 % CLA. No further changes in these variables were observed when CLA in the diet was raised to 1.0 % or 1.5 %. However, dietary CLA decreased mucosal levels of prostaglandin E2, thromboxane B2 and arachidonic acid in a dose-dependent manner. The present data indicate that dietary CLA can inhibit DMH-induced colon carcinogenesis by mechanisms probably involving increased apoptosis.

1,2-Dimethylhydrazine↗
PubMed2001

The spectrum of mutations in TSC1 and TSC2 in women with tuberous sclerosis and lymphangiomyomatosis.

Lymphangiomyomatosis (LAM) is a progressive and often fatal interstitial lung disease characterized by a diffuse proliferation of abnormal smooth muscle cells in the lungs. LAM is of unusual interest biologically because it affects almost exclusively young women. LAM can occur as an isolated disorder (sporadic LAM) or in association with tuberous sclerosis complex (TSC). Because only a minority of women with TSC develops symptomatic LAM, we hypothesized that a relationship might exist between the type of germline TSC1 or TSC2 gene mutation and the risk of developing LAM. We examined all 41 exons of the TSC2 gene and 21 coding exons of the TSC1 gene for mutations in a group of 14 women with both TSC and LAM using single-strand conformation polymorphism analysis. Seven mutations were found in TSC2 and one in TSC1. Of the seven patients with TSC2 mutations, two had the same in-frame exon 40 deletion and one had an exon 41 missense change. We conclude that germline mutations in the extreme carboxy-terminus of tuberin can result in LAM. Further studies will be required to determine whether mutations in exons 40 and 41 are associated with an increased incidence and/or severity of LAM in women with TSC.

Exons↗
PubMed2001

Smoking-related interstitial lung diseases: a concise review.

Interstitial lung diseases (also known as diffuse infiltrative lung diseases) are a heterogeneous group of parenchymal lung disorders of known or unknown cause. These disorders are usually associated with dyspnoea, diffuse lung infiltrates, and impaired gas exchange. The majority of interstitial lung diseases are of unknown cause. Known causes of interstitial lung disease include inhalation of organic and inorganic dusts as well as gases or fumes, drugs, radiation, and infections. This review summarizes the clinical, radiological, and histopathological features of four interstitial lung disorders that have been linked to smoking. These disorders include desquamative interstitial pneumonia, respiratory bronchiolitis-associated interstitial lung disease, pulmonary Langerhans' cell histiocytosis, and idiopathic pulmonary fibrosis. Available evidence suggests most cases of desquamative interstitial pneumonia, respiratory bronchiolitis-associated interstitial lung disease, and pulmonary Langerhans' cell histiocytosis are caused by cigarette smoking in susceptible individuals. Smoking cessation should be a main component in the initial therapeutic approach to smokers with these interstitial lung diseases. In addition, smoking appears to be a risk factor for the development of idiopathic pulmonary fibrosis.

Bronchiolitis Obliterans↗
PubMed2001

High short-term mortality following lung biopsy for usual interstitial pneumonia.

Usual interstitial pneumonia (UIP) is a specific histological pattern of interstitial pneumonia most often associated with the clinical syndrome of idiopathic pulmonary fibrosis (IPF). There is controversy regarding the use of surgical lung biopsy in the diagnosis of UIP, and the risk of lung biopsy in these patients is largely unknown. This study investigated the 30 day surgical mortality rate in patients undergoing surgical lung biopsy for UIP. Patients undergoing surgical lung biopsy over a 10-yr period from 1986-1995 with the ultimate diagnosis of UIP (with or without underlying connective tissue disease) were identified. Pathology, computed tomography, medical records, and survival were assessed. Ten of sixty patients with usual interstitial pneumonia were found to be dead within 30 days of surgical biopsy. All of these were patients with idiopathic UIP, unassociated with connective tissue disease (clinical condition of IPF). In conclusion, patients with usual interstitial pneumonia of the idiopathic type, who present with atypical features, may be at higher risk for death following surgical biopsy than patients presenting with more typical features or patients with other interstitial illnesses.

Adult↗
PubMed2001

Diagnosis of pulmonary embolism with use of computed tomographic angiography.

Pulmonary embolism (PE) is a common diagnostic problem, particularly in hospitalized patients. It remains a frequent cause of unexpected deaths. Traditionally, the diagnostic work-up for suspected PE has centered on the use of ventilation-perfusion (V-P) radionuclide lung scanning. However, V-P scanning does not provide adequate confirmation or exclusion of the diagnosis in the majority of patients who undergo this test. Although published guidelines advise further diagnostic testing after nondiagnostic V-P scans, clinicians infrequently perform such testing, and management decisions are commonly based on clinical judgment. In recent years, there has been an increasing interest in the use of computed tomographic (CT) angiography in the diagnostic evaluation of patients with suspected PE. Although there are unresolved issues regarding its sensitivity in detecting small peripheral emboli, CT angiography is more accurate than V-P scanning in the diagnosis of PE and yields other intrathoracic diagnoses. Herein we summarize the problems with the traditional approach centered on the use of V-P scanning in the diagnosis of PE and propose an alternative diagnostic strategy based primarily on the use of CT angiography.

Angiography↗
PubMed2001

Successful treatment of Whipple disease diagnosed 36 years after symptom onset.

Whipple disease is a rare infectious disorder with multiorgan manifestations and a widely varied clinical presentation. Involvement of the small intestine with resultant malabsorption is a classic finding, although extraintestinal manifestations such as fever and arthralgias may precede gastrointestinal symptoms by many years. We describe a 63-year-old man in whom Whipple disease was diagnosed 22 years after his initial presentation (36 years after symptom onset) with lymphadenopathy, when a biopsy yielded nonnecrotizing granulomas. His recent symptoms included persistent fatigue, weight loss, fever, and arthralgias. Endoscopic biopsy specimens from the distal duodenum showed features consistent with Whipple disease, and Tropheryma whippelii DNA was detected in both the small bowel biopsy specimen and the blood specimen by polymerase chain reaction and DNA probe hybridization. His symptoms resolved with long-term co-trimoxazole therapy. We discuss the protean manifestations of Whipple disease, the difficulties in clinical diagnosis, and the recent advances in the molecular diagnosis of this disorder.

Anti-Infective Agents↗
PubMed2001

Obstructive lung diseases: COPD, asthma, and many imitators.

Chronic obstructive pulmonary disease (COPD) is a common respiratory disorder that occurs in 10% to 15% of people who smoke, an estimated 16 million Americans. Asthma is also common. Spirometry is generally used to detect early COPD in smokers and to evaluate patients with respiratory symptoms. Although COPD and asthma account for most obstructive lung diseases, a broad spectrum of other disorders, including bronchiectasis, upper airway lesions, bronchiolar diseases, and some interstitial lung diseases, are associated with airflow obstruction. These less common forms of obstructive lung diseases are often misdiagnosed because of their uncommon occurrence and poor recognition. We describe the heterogeneous spectrum of disorders that can present with evidence of airflow obstruction and outline a diagnostic approach to obstructive lung disease.

Adult↗
PubMed2000

Gram-negative bacteria-binding protein, a pattern recognition receptor for lipopolysaccharide and beta-1,3-glucan that mediates the signaling for the induction of innate immune genes in Drosophila melanogaster cells.

Pattern recognition receptors, non-clonal immune proteins recognizing common microbial components, are critical for non-self recognition and the subsequent induction of Rel/NF-kappaB-controlled innate immune genes. However, the molecular identities of such receptors are still obscure. Here, we present data showing that Drosophila possesses at least three cDNAs encoding members of the Gram-negative bacteria-binding protein (DGNBP) family, one of which, DGNBP-1, has been characterized. Western blot, flow cytometric, and confocal laser microscopic analyses demonstrate that DGNBP-1 exists in both a soluble and a glycosylphosphatidylinositol-anchored membrane form in culture medium supernatant and on Drosophila immunocompetent cells, respectively. DGNBP-1 has a high affinity to microbial immune elicitors such as lipopolysaccharide (LPS) and beta-1,3-glucan whereas no binding affinity is detected with peptidoglycan, beta-1,4-glucan, or chitin. Importantly, the overexpression of DGNBP-1 in Drosophila immunocompetent cells enhances LPS- and beta-1,3-glucan-induced innate immune gene (NF-kappaB-dependent antimicrobial peptide gene) expression, which can be specifically blocked by pretreatment with anti-DGNBP-1 antibody. These results suggest that DGNBP-1 functions as a pattern recognition receptor for LPS from Gram-negative bacteria and beta-1, 3-glucan from fungi and plays an important role in non-self recognition and the subsequent immune signal transmission for the induction of antimicrobial peptide genes in the Drosophila innate immune system.

Acute-Phase Proteins↗
PubMed2000

Inhibition of mitogen-activated protein kinase by a Drosophila dual-specific phosphatase.

The Drosophila extracellular signal-regulated kinase (DERK) mitogen-activated protein kinase (MAPK) is involved in the regulation of multiple differentiation and developmental processes. Tight control of MAPK activity is critical for normal cell behaviour. We identified a novel Drosophila MAPK phosphatase (DMKP) cDNA from the expressed-sequence-tag database and characterized it. Analysis of the nucleotide sequence revealed an open reading frame encoding the 203-amino acid protein, with a calculated molecular mass of 23 kDa, which has a high amino acid sequence similarity with 'VH1-like' dual-specific phosphatases at the broad region near the catalytic sites. The expression of DMKP mRNA occurs from the late larval stages to adulthood in Drosophila development. The recombinant DMKP protein produced in yeast retained its phosphatase activity. When expressed in Schneider cells, DMKP dose-dependently inhibited DERK and Drosophila c-Jun N-terminal kinase activities with high selectivity towards DERK. However, DMKP did not have any affect on Drosophila p38 activity. When DMKP was expressed in yeast, it down-regulated the fus1-lacZ trans-reporter gene of the pheromone MAPK pathway without any significant effect on the high-osmolarity-glycerol-response pathway.

Amino Acid Sequence↗
PubMed2000

Role of glucose utilization in the restoration of hypophysectomy-induced hepatic cytochrome P450 2E1 by growth hormone in rats.

Growth hormone and insulin are the primary determinants for cytochrome P450 2E1 (CYP2E1) expression. The role of glucose on the induction of CYP2E1 by hypophysectomy and on the restorative effect by growth hormone was investigated in the rat liver. Western and Northern blot analyses revealed that hypophysectomy induced CYP2E1 by 5-fold at 1-4 weeks, relative to control, with a concomitant increase in CYP2E1 mRNA. Hypophysectomized rats (HXR) showed a 20% reduction in the plasma glucose level. Hypophysectomy-induced increase in the CYP2E1 mRNA was completely abolished by glucose feeding in drinking water (10%) for 7 days. Treatment of HXR with hGH (2 I.U./kg, twice a day, for 7 days) inhibited the increases in CYP2E1 protein and mRNA levels with restoration of the plasma glucose level. In contrast to the effect of human growth hormone (hGH) on CYP2E1 in HXR with free access to foods, CYP2E1 expression failed to be restored by hGH in starving HXR. However, glucose feeding of starving HXR abolished the induction of CYP2E1. Effects of hypophysectomy and hGH treatment were studied in streptozotocin-induced diabetic rats. Insulin, but not hGH, prevented an increase in CYP2E1 mRNA in diabetic rats. The hepatic CYP2E1 induction in hypophysectomized diabetic rats was inhibited by hGH treatment, indicating that the hGH effect on CYP2E1 expression did not involve insulin production. These results provide evidence that the induction of hepatic CYP2E1 by hypophysectomy may result from reduced glucose utilization, and that the effect of hGH on CYP2E1 expression may be mediated with enhanced glucose utilization, but not with insulin production.

Animals↗
PubMed2000

Filamentous polymers induced by overexpression of a novel centrosomal protein, Cep135.

A novel 135 kDa centrosomal component (Cep135) was identified by immunoscreening of a mammalian expression library with monoclonal antibodies raised against clam centrosomes. It is predicted to be a highly coiled-coil protein with an extensive alpha-helix, suggesting that Cep135 is a structural component of the centrosome. To evaluate how the protein is arranged in the centrosomal structure, we overexpressed Cep135 polypeptides in CHO cells by transient transfection. HA- or GFP-tagged full (amino acids 1-1144) as well as truncated (#10, 29-1144; Delta3, 29-812) polypeptides become localized at the centrosome and induce cytoplasmic dots of various size and number in CHO cells. Centrosomes are associated with massive approximately 7 nm filaments and dense particles organized in a whorl-like arrangement in which parallel-oriented dense lines appear with a regular approximately 7 nm periodicity. The same filamentous aggregates are also detected in cytoplasmic dots, indicating that overexpressed Cep135 can assemble into elaborate higher-ordered structures in and outside the centrosome. Sf9 cells infected with baculovirus containing Cep135 sequences induce filamentous polymers which are distinctive from the whorl seen in CHO cells; #10 forms highly packed spheroids, but the Delta3-containing structure looks loose. Both structures show an internal repeating unit of dense and less dense stripes. Although the distance between the outer end of two adjacent dense lines is similar between two types of polymers ( approximately 120 nm), the dense stripe of Delta3 polymers ( approximately 40 nm) is wider than #10 ( approximately 30 nm). The light band of Delta3 ( approximately 40 nm) is thus narrower than #10 ( approximately 60 nm). Since thin fibers are frequently seen to extend from one dense line to the next, the coiled-coil rod of Cep135 may span the light band. These results suggest that overexpressed Cep135 assemble into distinctive polymers in a domain-specific manner.

Animals↗
PubMed2000

Lipopolysaccharide-activated kinase, an essential component for the induction of the antimicrobial peptide genes in Drosophila melanogaster cells.

Eukaryotic organisms use a similar Rel/NF-kappaB signaling cascade for the induction of innate immune genes. In Drosophila, lipopolysaccharide (LPS) signal-induced activation of the Rel/NF-kappaB family transcription factors is an essential step in the transcriptional activation of inducible antimicrobial peptide genes. However, the mechanism by which the LPS-induced signaling pathway proceeds remains largely unknown. Here we have cloned a novel Drosophila LPS-activated kinase (DLAK) that is structurally related to mammalian IkappaB kinases. DLAK is expressed and transiently activated in LPS-responsive Drosophila cells following LPS stimulation. Furthermore, DLAK can interact with Cactus, a Drosophila IkappaB and phosphorylate recombinant Cactus, in vitro. Overexpression of dominant-negative mutant DLAK (DLAK(K50A)) blocks LPS-induced Cactus degradation. DLAK-bound Cactus can be degraded in a LPS signal-dependent fashion, whereas the DLAK(K50A) mutant-bound Cactus is completely resistant to degradation in the presence of LPS. The DLAK(K50A) mutant also inhibits nuclear kappaB binding activity and kappaB-dependent diptericin reporter gene activity in a dose-dependent manner, but the kappaB-dependent diptericin reporter gene activity can be rescued by overexpression of wild type DLAK. Moreover, mRNA analysis of various kappaB-dependent antimicrobial peptide genes shows that LPS inducibility of these genes is greatly impaired in cells overexpressing DLAK(K50A). These results establish that DLAK is a novel LPS-activated kinase, which is an essential signaling component for the induction of antimicrobial peptide genes following LPS treatment in Drosophila cells.

Amino Acid Sequence↗
PubMed2000

Inhibition of LPS-induced NO production and NF-kappaB activation by a sesquiterpene from Saussurea lappa.

To elucidate the molecular mechanisms for the suppression of LPS-induced nitric oxide (NO) production by a dehydrocostus lactone (DL) from Saussurea lappa, we examined the preventive effect of this compound on NF-kappaB activation in LPS-treated RAW 264.7 macrophages and U937 human monocytic cells. The results suggest that the suppression of NO production is mediated by the inhibitory action on the i-NOS gene expression through the inactivation of NF-kappaB and this sesquiterpene lactone can act as a pharmacological inhibitor of the NF-kappaB activation.

Animals↗
PubMed2000

Neuroprotective effect of green tea extract in experimental ischemia-reperfusion brain injury.

Eicosanoids accumulation and formation of oxygen free radicals have been implicated in the pathogenesis of ischemia/reperfusion brain injury. In the present study, we examined whether green tea extract protects against ischemia/reperfusion-induced brain injury by minimizing eicosanoid accumulation and oxygen radical-induced oxidative damage in the brain. Green tea extract (0.5%) was orally administered to Wistar rats for 3 weeks before induction of ischemia. Ischemia was induced by the occlusion of middle cerebral arteries for 60 min and reperfusion was achieved for 24 h. Infarction volume in the ipsilateral hemisphere of ischemia/reperfusion animals was 114 +/- 16 mm(3) in the 0.5% green tea pretreated animals compared to 180 +/- 54 mm(3) in left hemisphere of nontreated animals. Green tea extract (0.5%) also reduced ischemia/reperfusion-induced eicosanoid concentration: Leukotriene C(4) (from 245 +/- 51 to186 +/- 22), prostoglandin E(2) (from 306 +/- 71 to 212 +/- 43) and thromboxane A(2) (327 +/- 69 to 251 +/- 87 ng/mg protein). Ischemia/reperfusion-induced increases of hydrogen peroxide level (from 688 +/- 76 to 501 +/- 99 nmole/mg protein), lipid peroxidation products (from 1010 +/- 110 to 820 +/- 70 nmole/mg protein) and 8-oxodG formation (from 1.3 +/- 0.3 to 0.8 +/- 0.2 ng/microg DNA, x10(-2)) were also reduced. Moreover, 0.5% green tea extract also reduced the apoptotic cell number (from 44 +/- 11 to 29 +/- 1 in the striatum, and from 72 +/- 11 to 42 +/- 5 apoptotic cells/high power field in the cortex region). Green tea extract pretreatment also promoted recovery from the ischemia/reperfusion-induced inhibition of active avoidance. The present study shows that the minimizing effect of green tea extract on the eicosanoid accumulation and oxidative damage in addition to the reduction of neuronal cell death could eventually result in protective effect on the ischemia/reperfusion-induced brain injury and behavior deficit.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2000

Inhibitors of nitric oxide synthesis and TNF-alpha expression from Magnolia obovata in activated macrophages.

Nitric oxide (NO) and tumor necrosis factor-alpha (TNF-alpha) are the major mediators produced in activated macrophages which contribute to the circulatory failure associated with septic shock. An activity-guided fractionation of an MeOH extract of stem bark of Magnolia obovata afforded two inhibitors of NO production in lipopolysaccharides (LPS)-activated macrophages by the suppression of i-NOS expression. Their structures were elucidated by spectroscopic methods to be magnolol and honokiol with IC50 values of 16.8 and 6.4 microM, respectively. They also inhibited the production of TNF-alpha in LPS-activated macrophages. Thus, these compounds may be possible candidates for the development of new drugs to treat endotoxemia accompanied by the overproduction of NO and TNF-alpha.

Animals↗
PubMed2000

The essential role of phosphatidylinositol 3-kinase and of p38 mitogen-activated protein kinase activation in the antioxidant response element-mediated rGSTA2 induction by decreased glutathione in H4IIE hepatoma cells.

The protective adaptive response to electrophiles and reactive oxygen species is mediated by the enhanced expression of the phase II detoxifying genes through antioxidant response elements (AREs). The current study was designed to identify the signaling pathways responsible for the expression of rGSTA2 in response to cellular oxidative stress and to establish the molecular mechanistic basis. Deprivation of cystine and methionine caused oxidative stress in H4IIE hepatoma cells as evidenced by a marked decrease in the reduced glutathione (first order rate constant = 0.056 h(-1); t(1/2) = 12.6 h) and an increase in pro-oxidant production. Electrophoretic mobility shift assay revealed that the ARE complex, consisting of Nrf-1/2 and Maf proteins, was activated 12 to 48 h after sulfur amino acid deprivation (SAAD). The rGSTA2 mRNA level was elevated by SAAD beginning at 24 h, whereas the rGSTA2 subunit was maximally induced at 48 h. Nuclear ARE activation and rGSTA2 mRNA increase were both completely inhibited by wortmannin or LY294002, the phosphatidylinositol 3-kinase (PI3-kinase) inhibitors. The p38 mitogen-activated protein (MAP) kinase was activated at 0.5 to 3 h after SAAD, followed by sustained diminished activation up to 12 h. Inhibition of p38 MAP kinase by SB203580 prevented the ARE-mediated rGSTA2 induction. The activation of p38 MAP kinase, however, failed to be inhibited by wortmannin or LY294002, showing that PI3-kinase is not involved in the activation of p38 MAP kinase. Data showed that PI3-kinase plays an essential role in the ARE-mediated rGSTA2 induction by oxidative stress after SAAD, which activates the p38 MAP kinase and leads to rGSTA2 induction.

Amino Acids, Sulfur↗
PubMed2000

Nonspecific interstitial pneumonia: variable appearance at high-resolution chest CT.

PURPOSE: To describe the computed tomographic (CT) findings in patients with nonspecific interstitial pneumonia (NSIP) and to compare these with the CT findings of other chronic infiltrative lung diseases. MATERIALS AND METHODS: Findings in 50 patients with biopsy-proved NSIP and a CT scan were reviewed by two thoracic radiologists in consensus. After the findings were described, the observers judged whether the findings were compatible with previously published descriptions of NSIP or whether the findings would support the diagnosis of a different chronic infiltrative lung disease. RESULTS: Eleven (22%) of the 50 patients had CT findings that were compatible with previous descriptions of NSIP. Sixteen (32%) patients had CT findings that were more compatible with usual interstitial pneumonia. The other 23 (46%) patients had findings that were nondiagnostic or most compatible with the diagnosis of another chronic infiltrative lung disease. CONCLUSION: Contrary to previously published articles, there are a wide variety of CT findings in cases of NSIP.

Adult↗