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Biomedical subjects

O J Kwon

Publications and source records attributed to O J Kwon.

At least 55 records · Page 3Linked to original sources
PubMed1998

Bronchial stenosis due to anthracofibrosis.

STUDY OBJECTIVES: To define the clinical characteristics of the patients showing bronchoscopic findings of bronchial narrowing or obliteration with black pigmentation on overlying mucosa (we named this finding as "anthracofibrosis"), and to determine the association of anthracofibrosis with tuberculosis. PATIENTS AND METHODS: The subjects of this study consisted of 28 patients; 8 men and 20 women, ranging in age from 42 to 86 years. The distinctive clinical features, natures of bronchoscopic lesions, and radiologic findings were analyzed retrospectively and summarized. Bacteriologic studies and results of pathologic examinations were also assessed. RESULTS: Chief complaints were cough (20/28) and dyspnea on exertion (17/28). The abnormal bronchoscopic findings were identified most frequently in the right middle lobe bronchus (n=21/28) while more than one part of the bronchial tree was narrowed in 22 patients. Abnormalities of bronchial airways on CT were associated with peribronchial cuffs of soft tissue or surrounding lymph nodes. In 17 patients, active tuberculous infection was confirmed either bacteriologically (n=15) and/or histologically (n=8). Pathologic study of the lesion obtained by bronchoscopic biopsy or thoracotomy showed dense bronchial and/or peribronchial fibrosis with interspersed black pigments. CONCLUSIONS: These findings strongly suggest that bronchial stenosis or obliteration with anthracotic pigmentation in the mucosa was caused by a fibrotic response to active or old tuberculous infection. To prevent the spread of tuberculosis and avoid unnecessary invasive procedures, detailed examinations for the presence of active tuberculosis should be performed in patients with this unique bronchoscopic finding.

Adult↗
PubMed1998

Localized form of bronchioloalveolar carcinoma: FDG PET findings.

OBJECTIVE: The aim of our study was to describe 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) findings of a localized form of bronchioloalveolar carcinoma and to compare those findings with other cell types of lung cancer. SUBJECTS AND METHODS: FDG PET was performed in 48 patients with lung cancer. The patients had carcinomas of various cell types: bronchioloalveolar carcinoma (n = 9), squamous cell carcinoma (n = 11), adenocarcinoma (n = 22), and other cell types (n = 6). Using FDG PET, we compared peak standardized uptake values among the various cell types of lung cancer. CT and pathologic findings for patients with bronchioloalveolar carcinoma were also reviewed. RESULTS: Overall, 48 malignant tumors showed a mean peak standardized uptake value of 8.0 +/- 4.1. The mean peak standardized uptake value was 3.5 +/- 2.2 for bronchioloalveolar carcinoma, 10.8 +/- 4.4 for squamous cell carcinoma, and 8.8 +/- 3.2 for adenocarcinoma. The mean peak standardized uptake value for bronchioloalveolar carcinoma was significantly lower than that for adenocarcinoma and squamous cell carcinoma (p < .001). On high-resolution CT scans, bronchioloalveolar carcinomas appeared as areas of ground-glass opacity (n = 4), as nodules (n = 2), as masses (n = 2), and as a ground-glass opacity plus consolidation (n = 1). On pathologic examination, bronchioloalveolar carcinomas were well differentiated, having moderate degrees of nuclear atypism, mild degrees of mitotic figure, desmoplasia, and necrosis. CONCLUSION: The localized form of bronchioloalveolar carcinoma shows significantly lower peak standardized uptake values than do other lung carcinomas. Thus, bronchioloalveolar carcinoma can be a potential cause of false-negative findings of malignancy on FDG PET scans. When bronchioloalveolar carcinoma is suggested, FDG PET results should be interpreted in combination with high-resolution CT findings.

Adenocarcinoma↗
PubMed1998

Nonspecific interstitial pneumonia with fibrosis: high-resolution CT and pathologic findings.

OBJECTIVE: The purpose of our study was to describe high-resolution CT findings of nonspecific interstitial pneumonia with fibrosis and to compare findings seen on CT with pathologic findings. MATERIALS AND METHODS: High-resolution CT findings of biopsy-proven non-specific interstitial pneumonia with fibrosis from 23 consecutive patients (one man and 22 women) were analyzed retrospectively by two chest radiologists. CT findings were compared with pathologic findings. RESULTS: The predominant high-resolution CT finding, seen in all patients, was bilateral patchy areas of ground-glass opacity with (35%) or without (65%) areas of consolidation. Irregular linear opacities (87%), thickening of bronchovascular bundles (65%), and bronchial dilatation (52%) were also frequently seen. Honeycombing was not seen in any patient. All parenchymal abnormalities showed subpleural predominance. Areas of ground-glass opacity with or without irregular linear opacity or bronchial dilatation on CT corresponded pathologically to areas of interstitial thickening caused by varying degrees of interstitial inflammation and fibrosis showing temporal uniformity. Areas of consolidation, seen at five biopsy sites, represented the areas of bronchiolitis obliterans organizing pneumonia, foamy cell collections in alveolar spaces, or microscopic honeycombing with mucin stasis. CONCLUSION: On high-resolution CT, nonspecific interstitial pneumonia with fibrosis is most commonly revealed as patchy subpleural areas of ground-glass opacity mixed with irregular linear opacity or bronchial dilatation. These areas represent interstitial thickening caused by varying degrees of interstitial inflammation, fibrosis, or both.

Adult↗
PubMed1998

Gamma irradiation and ozone treatment for inactivation of Escherichia coli O157:H7 in culture media.

A study was conducted to investigate the reduction and elimination of Escherichia coli O157:H7 by the effects of gamma irradiation and ozone treatment. Log phase cells were found to be more sensitive to gamma irradiation than stationary phase cells. E. coli O157:H7 was found to be considerably more resistant to irradiation at -18 degrees C than at 20 degrees C. The D values for this organism for treatment with ozone in tryptic soy agar were higher than those for treatment with ozone in phosphate buffer. Gamma irradiation at a dose of 1.5 kGy or ozone treatment at a concentration of 3 to 18 ppm for 20 to 50 min was required to assure the elimination of E. coli O157:H7.

Buffers↗
PubMed1997

Intravascular lymphomatosis: a clinicopathological study of two cases presenting as an interstitial lung disease.

AIMS: Intravascular lymphomatosis is an uncommon type of non-Hodgkin's lymphoma characterized by intravascular proliferation of neoplastic lymphoid cells. Although the tumour is basically a systemic disease, eventually involving multiple organs, primary presentation in the lung is rare. METHODS AND RESULTS: We describe the clinicopathological features of two patients with intravascular lymphomatosis presenting in the lung. One patient complained of fever, headache and chest pain; the other, of dyspnoea on exertion and headache. Both patients showed reticulonodular density on chest radiography and decreased diffusion capacity. Lung biopsy showed features characteristic of intravascular lymphomatosis. Malignant lymphoid cells were CD30 positive T-cells of anaplastic large cell type in one patient and B-cells of large cell type in the other. There was a poor response to chemotherapy and both patients died of the disease within 3 months of diagnosis. CONCLUSIONS: These cases and 10 previous reports illustrate the need to include intravascular lymphomatosis in the differential diagnosis of interstitial lung disease.

Aged↗
PubMed1997

Reversible cystic disease associated with pulmonary tuberculosis: radiologic findings.

PURPOSE: The authors describe radiologic findings of cystic lung disease associated with pulmonary tuberculosis. MATERIALS AND METHODS: Three immunocompetent women with pulmonary tuberculosis were seen with acute respiratory failure and diffuse bilateral pulmonary opacity depicted at admission chest radiography. The women did not have acquired immunodeficiency syndrome, or AIDS. They were aged 26, 27, and 52 years. RESULTS: Follow-up radiography and computed tomography showed multiple air-filled cystic lesions in both lungs, which disappeared almost completely after antituberculous chemotherapy (isoniazid, rifampin, ethambutol hydrochloride, and pyrazinamide). CONCLUSION: Pulmonary tuberculosis manifested with reversible multiple cystic lung disease in three immunocompetent patients.

Adult↗
PubMed1997

Tuberculosis of the trachea and main bronchi: CT findings in 17 patients.

OBJECTIVE: The purpose of our study was to describe the CT findings of tuberculosis of the trachea and main bronchi. MATERIALS AND METHODS: Initial (n = 17) and follow-up (n = 7) CT scans were available from 17 patients (five men and 12 women; aged 25-82 years old) with tracheobronchial tuberculosis. The diagnosis of tuberculosis was based on bronchoscopic, microbiologic, or pathologic findings. RESULTS: The trachea (n = 6), the right main bronchus (n = 6), and the left main bronchus (n = 4) were involved in 10 patients with actively caseating tuberculosis. These airways showed irregular (n = 11) or smooth (n = 4) circumferential narrowing and occlusion (n = 1). Also, the trachea (n = 2), the right main bronchus (n = 1), and the left main bronchus (n = 6) were involved in seven patients with fibrotic tuberculosis. These airways showed smooth (n = 4) or irregular (n = 3) circumferential narrowing and occlusion (n = 2). Mediastinitis (increased densities in mediastinal fat) was seen in four of 10 patients with active tuberculosis but not in any of the seven patients with fibrotic disease. Tracheal tuberculosis, which has always been associated with bronchial disease, involved the distal trachea and exceeded 3 cm in length. After the seven patients underwent initial scans and antituberculous chemotherapy, serial CT scans showed improvement in seven of 11 lesion sites: normalized airways (n = 4) or smoothing from irregular narrowing (n = 3). The remaining four sites showed no change. CONCLUSION: On CT scans, actively caseating tracheobronchial tuberculosis showed circumferential and predominantly irregular luminal narrowing and mediastinitis. When fibrotic disease was found, a CT scan revealed equal distribution of smooth and irregular narrowing and less wall thickening than was seen in patients with active disease. On CT scans, tracheal tuberculosis involved the long segment of the distal trachea, a condition associated with bronchial tuberculosis.

Adult↗
PubMed1997

The role of nitric oxide in the immune response of tuberculosis.

Nitric oxide (NO) formed by the action of inducible form of nitric oxide synthase (iNOS), reacts with oxygen radical forming reactive nitrogen intermediate (RNI). NO and related RNI have been reported to possess antimycobacterial activity. Macrophages can inhibit the proliferation of Mycobacterium tuberculosis by producing NO. In murine models, the ability of macrophages to produce NO can determine the susceptibility of the host to M. tuberculosis and the virulence of M. tuberculosis. However, it is still not clear whether NO is involved in the defense mechanism against M. tuberculosis in humans. We have demonstrated that human peripheral blood mononuclear cells (PBMC) and airway epithelial cells can express iNOS mRNA expression and produce NO production in response to tubercle bacilli stimulation. Furthermore, H37Ra, avirulent strain of M. tuberculosis, induces a larger amount of NO in cultured PBMC than H37Rv, virulent strain, does. There was no difference in NO production between healthy volunteers and patients with tuberculosis. NO production in airway epithelial cells is closely related with IFN gamma concentration. The balance of stimulatory cytokines and inhibitory cytokines for NO production may play a critical role in the defense mechanism against M. tuberculosis considering that NO production is upregulated by IFN gamma, TNF alpha, and IL-1 beta and downregulated by IL-10 and TGF beta. The study of immune response to M. tuberculosis including NO production may give us a better understanding of the pathogenesis of tuberculosis.

Antibody Formation↗
PubMed1996

Localisation and expression of beta-adrenoceptor subtype mRNAs in human lung.

The cellular localisation and distribution of mRNAs encoding beta-adrenoceptor subtypes in human lung were studied by in situ hybridisation and Northern blot analysis. The 851-bp SmaI/PvuII fragment of human beta 1-adrenoceptor cDNA, the 439-bp SmaI fragment of human beta 2-adrenoceptor cDNA and the 975-bp SmaI fragment of human beta 3-adrenoceptor cDNA bound to single mRNA species of approximately 3.2 kb, 2.2 kb and 2.3 kb in size, respectively. Human lung and heart and rabbit lung expressed both beta 1- and beta 2-adrenoceptor mRNAs with no detectable level of beta 3-adrenoceptor mRNA, while rabbit perirenal adipose tissue expressed beta 1-, beta 2- and beta 3-adrenoceptor mRNAs. Cultured human airway epithelial cells and airway smooth muscle cells expressed only beta 2-adrenoceptor mRNA. In situ hybridisation in human lung, using 35S-labelled antisense RNA probes revealed a high level of expression of beta 1- and beta 2-adrenoceptor mRNAs in the pulmonary blood vessels, high level of expression of beta 2-adrenoceptor mRNA in the alveolar walls with less expression of beta 1-adrenoceptor mRNA. There was a moderate expression of beta 2-adrenoceptor but not beta 1-adrenoceptor mRNA in airway epithelium and smooth muscle of peripheral airways and no detectable beta 3-adrenoceptor mRNA in any lung structures.

Animals↗
PubMed1996

Identification of a novel protein containing two C2 domains selectively expressed in the rat brain and kidney.

We have isolated and characterized a rat brain cDNA clone which encodes a new protein of 474 amino acids in length which contains two C2 domains structurally homologous to those present in synaptotagmins. The overall amino acid identity in C2 domains between this protein and the synaptotagmins is 36-44%. This protein also contains 3 putative consensus sequences for phosphorylation by cAMP-dependent protein kinase. RNA blot hybridization revealed a 3.0 kb transcript abundantly expressed only in the rat brain and the kidney. Thus, we called this brain/kidney protein (B/K). In situ hybridization and Northern blot analyses showed that the B/K transcript was found in forebrain including the olfactory bulb, cerebral cortex, hippocampus, and hypothalamus. In the kidney, high levels of B/K transcript were expressed in the papillary region of the inner medulla, the inner stripe of the outer medulla and the cortex. The selective expression in forebrain and kidney suggests that B/K may be involved in similar cAMP-dependent processes at these very different sites.

Amino Acid Sequence↗
PubMed1996

Characterization of an L-type calcium channel expressed by human retinal Müller (glial) cells.

The traditional notion that glial cells are permeable only to potassium has been revised. For example, glia from various parts of the nervous system have calcium-permeable ion channels. Since characterization of the calcium channels in glia is limited, the purpose of this study was to determine the molecular identity and examine the functional properties of a voltage-gated calcium channel expressed by Müller cells, the predominant glia of the retina. Whole-cell and perforated-patch recordings of human Müller cells in culture revealed a high threshold voltage-activated calcium current that is blocked by dihydropyridines, but not by omega-conotoxin GVIA or omega-conotoxin MVIIC. RT-PCR of cultured human Müller cells using primers specific for the calcium channel subunits demonstrated the expression of an L-type channel composed of the alpha 1D, alpha 2 and beta 3 subunits. The alpha 2 subunit of the Müller cell calcium channel is a splice variant which is distinct from either the skeletal muscle alpha 2s or the brain alpha 2b. Our electrophysiological experiments indicate that the alpha 1D/alpha 2/beta 3 calcium channel is functionally linked with the activation of a potassium channel that may serve as one of the pathways for the redistribution by Müller cells of excess retinal potassium.

Amino Acid Sequence↗
PubMed1996

Bronchioloalveolar carcinoma: focal area of ground-glass attenuation at thin-section CT as an early sign.

PURPOSE: To assess an early thin-section computed tomographic (CT) finding of the localized formation of bronchioloalveolar carcinoma (BAC). MATERIALS AND METHODS: From October 1994 to September 1995, four consecutive patients with biopsy-proved BAC were studied. Thin-section CT (n=4), radiographic (n=4), pathologic (n=4), and positron emission tomographic (n=2) findings were analyzed. RESULTS: Chest radiographs showed focal areas of poorly defined nodules (n=2) and poorly defined opacity (n=2). At thin-section CT, lesions appeared as isolated areas of ground-glass attenuation (n=2) and mixed areas of ground-glass attenuation and consolidation (n=2). The areas of ground-glass attenuation were 1.8-11 cm in longest diameter. A focal, isolated area of ground-glass attenuation changed into mixed areas with consolidation at serial CT in one patient. Mucinous and nonmucinous BACs were observed in two patients each. Positron emission tomography showed false-negative results for malignancy. CONCLUSION: Focal areas of ground-glass attenuation at CT could be an early sign of localized BAC.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1996

Utility of CT in the evaluation of pulmonary tuberculosis in patients without AIDS.

OBJECTIVE: To assess the utility of CT in the evaluation of pulmonary tuberculosis in patients without AIDS. PATIENTS AND METHODS: This-section CT scans for suspicion of pulmonary tuberculosis were obtained from 226 patients. A total of 38 patients were excluded; the reasons were unavailability of final results (n = 18), patient unavailability for follow-up (n = 13), and coexistence of tuberculosis and aspergilloma (n = 7). The results from 188 patients were used for this study. After assessing the patterns of parenchymal lesion, involved segments, and presence of cavity, bronchiectasis, and bronchogenic spread of the lesion with CT, tentative diagnosis and disease activity were recorded. RESULTS: With CT, 133 of 146 patients (91%) with tuberculosis were correctly diagnosed as having pulmonary tuberculosis whereas 32 of 42 patients (76%) without tuberculosis were correctly excluded. CT diagnosis of lung cancer (n = 8), bacterial pneumonia (n = 2), pulmonary metastasis (n = 1), chronic hypersensitivity pneumonia (n = 1), and diffuse panbronchiolitis (n = 1) turned out to be tuberculosis. Conversely CT diagnoses of tuberculosis appeared pathologically as lung cancer (n = 5), bacterial pneumonia (n = 4), and pulmonary paragonimiasis (n = 1). Active (71/89, 80%) and inactive state (51/57, 89%) of disease respectively could be correctly differentiated by CT. CONCLUSION: CT can be helpful in the diagnosis of pulmonary tuberculosis in most cases. On the basis of CT findings, distinction of active from inactive disease can be made in most cases.

Adult↗
PubMed1996

Menstrual and reproductive factors related to the risk of breast cancer in Korea. Ovarian hormone effect on breast cancer.

To support the ovarian hormone hypothesis in the etiology of breast cancer, a hospital-based case-control study with community controls was conducted to evaluate the relationship of intervals among menstrual and reproductive events to the risk of breast cancer in Korea. The cases were 190 breast cancer patients, who had been histologically diagnosed at Seoul National University Hospital from Jan. 1, 1993 to Jun. 30, 1994. Included were cancer-free women, who had undertaken the Gynecological examination at the same hospital (n=190). Women recruited for a survey of diabetes prevalence in Yonchon County, adjacent to Seoul City, were taken as a community control group (n=190). Information on menstrual and reproductive factors with other life-styles was collected through a direct interview by the well-trained interviewers. The adjusted odds ratios and the 95% confidence intervals were based on the unconditional logistic regression model. Likelihood ratio test for trend was applied for the ordinal variables. Early age at menarche, late age at natural menopause, late age at first full term pregnancy, and fewer number of full term pregnancies are independently associated with the high risk of breast cancer in Korea. Moreover, the interval between the age at menarche and the age at natural menopause of community controls (29.9+/-6.15 years) was significantly shortened compared to breast cancer cases (34.9+/-4.42 years). Particularly noteworthy was that intervals between the age at menarche and the age at first full term pregnancy of both control groups (9.0+/-3.72 years for hospital controls; 7.2+/-4.04 years for community controls) were significantly shortened compared to breast cancer cases (11.0+/-4.51 years). These findings support the hypothesis that the longer exposure to ovarian hormones during the reproductive years, the higher the risk of breast cancer.

Adult↗
PubMed1995

Genetic mapping of the mouse genes encoding the voltage-sensitive calcium channel subunits.

The genes encoding the alpha 1 and beta subunits of voltage-sensitive calcium channel were mapped in the mouse by analysis of the progeny of two multilocus crosses. The alpha 1, beta 2, and beta 4 subunit genes, termed Cchna1, Cchb2, and Cchb4, are located at different sites on proximal Chr 2, while the beta 3 subunit gene Cchb3 maps to Chr 15 near Wnt1. These results together with previous mapping data indicate that the calcium channel genes are dispersed in the mouse genome, unlike the sodium channel genes, which are clustered.

Animals↗
PubMed1995

HLA class II analysis in Jewish Israeli narcoleptic patients.

HLA class II was investigated in eight Jewish narcoleptic patients, representing the total of such patients known in Israel at present, and in three patients suffering from sleep disturbances other than narcolepsy. All (11 out of 11) patients carried the serologic specificities DR2, DQ6 (DQ1). At the DNA level, all narcoleptics were found to be DRB1*1501, DQA1*0102, DQB1*0602 which indicates that the susceptibility gene may be located within the HLA class II region, DR, and/or DQ. As for the nonnarcoleptic patients with idiopathic hypersomnia, they carried different alleles of DR2 and DQ6, namely DRB1*1502, DQA1*0103, DQB1*0601. This study confirms that the incidence of narcolepsy in Israel is extremely low and that HLA class II genes or a gene(s) tightly linked to them are involved in the disease.

Alleles↗