Biomedical subjects

S C Chu

Publications and source records attributed to S C Chu.

At least 19 recordsLinked to original sources

PubMed2000

Significant differences in serum activities of matrix metalloproteinase-2 and -9 between HCV- and HBV-infected patients and carriers.

To examine the possible involvement of MMP-9 and -2 in the development of liver diseases caused by HCV or HBV infection, serum activities of both enzymes were studied by zymograph. Eight groups of subjects (60 for each) were examined in the study: healthy control, patients with hepatoma, liver cirrhosis, chronic hepatitis B or chronic hepatitis C, and carriers positive for HBsAg, both HBsAg and HBeAg, or anti-HCV. The results showed significant changes in the MMP-9 and -2 activities in the carriers. The presence of HBeAg was accompanied by a highest activity of MMP-2 and an inversely correlated (r=-0.578, P=<0.001), lowest activity of MMP-9 among all groups. For those with active liver diseases, MMPs activities were fluctuated at each stage of pathological symptoms. Chronic hepatitis B and C patients had significant different serum MMP-2 and -9 activities. These findings imply an influence on the balance of MMPs system by the existence of virus that might influence the following progression of liver disease, and a distinction between the pathological mechanisms of HCV and HBV. Since the serum MMPs activities were significantly varied between each stage of liver disease, an individual profile of these parameters might serve as an easy accessing serum marker to monitor the progression of liver disease.

Alanine Transaminase↗

PubMed2000

Pulmonary lymphangioleiomyomatosis: correlation of ventilation-perfusion scintigraphy, chest radiography, and CT with pulmonary function tests.

PURPOSE: To determine the findings on ventilation-perfusion (V-P) scintigrams, computed tomographic (CT) scans, and chest radiographs and correlate them with pulmonary function test results in patients with lymphangioleiomyomatosis. MATERIALS AND METHODS: V-P scintigraphy, chest radiography, conventional and thin-section CT, and pulmonary function tests were performed in 39 patients. The images were graded on a scale of 0 (normal) to 3 (severely abnormal). RESULTS: Imaging abnormalities were found on 92% of ventilation scintigrams, 92% of perfusion scintigrams, 79% of chest radiographs, 100% of CT scans, and 100% of thin-section CT scans. On ventilation scintigrams, 28 (72%) patients demonstrated a speckling pattern. On CT scans, all patients had pulmonary cysts. Univariate analysis showed that extent of disease on chest radiographs and CT scans, cyst size, V-P abnormalities, and degree of speckling were inversely correlated with forced expiratory volume in one second (FEV(1)), diffusing capacity of lung for carbon monoxide, and the ratio of FEV(1) to forced vital capacity (FVC) (P <.01) but not with FVC and total lung capacity. Larger cyst size correlated with extent of disease at CT, but not significantly (P =.056). CONCLUSION: Scintigraphic and radiologic abnormalities are seen in a majority of patients with lymphangioleiomyomatosis. On ventilation scintigrams, a frequently seen speckling pattern may be related to accumulation of radionuclide in pulmonary cysts-a hallmark of the disease at CT. Findings with each imaging modality correlate with certain pulmonary functions.

Adult↗

PubMed2000

Lymphangioleiomyomatosis: abdominopelvic CT and US findings.

PURPOSE: To describe the abdominal computed tomographic (CT) and ultrasonographic (US) findings in patients with thoracic lymphangioleiomyomatosis (LAM) and to relate the prevalence of the findings to the severity of pulmonary disease. MATERIALS AND METHODS: Eighty patients with LAM underwent chest and abdominopelvic CT and abdominopelvic US. The images were reviewed prospectively by one radiologist, and the abdominal findings were recorded and correlated with the severity of pulmonary disease at thin-section CT. RESULTS: Sixty-one (76%) of 80 patients had positive abdominal findings. The most common abdominal findings included renal angiomyolipoma (AML) in 43 patients (54%), enlarged abdominal lymph nodes in 31 (39%), and lymphangiomyoma in 13 (16%). Less common findings included ascites in eight (10%), dilatation of the thoracic duct in seven (9%), and hepatic AML in three (4%). A significant correlation (P =.02) was observed between enlarged abdominal lymph nodes and increased severity of lung disease. CONCLUSION: There are characteristic abdominal findings in patients with LAM that, in conjunction with the classic thin-section CT finding of pulmonary cysts, are useful in establishing this diagnosis.

Abdomen↗

PubMed1999

Fluctuation of serum leptin level in rats after ovariectomy and the influence of estrogen supplement.

In order to understand the mechanism of increasing body fat in perimenopausal and postmenopausal women, an ovariectomy-induced obesity model was used to study the role of leptin. In this investigation, a long-term study lasted for 13 weeks was conducted to monitoring the change of serum leptin level in rats after the loss of estrogen, and also to examine the influence of estrogen replacement. The results showed that three weeks after the removal of ovaries the body weight of Ovx rats was already significantly higher than the other two groups, and continued to gain more weight thereafter. Accompanying with the significant weight gain was the changes in the serum leptin levels. The leptin concentration declined gradually during the first half of experimental period, dropping down to an almost undetectable level at week 7 (0.216+/-0.132 ng/ml). Subsequently, its concentration began to elevate, and by the end of experiment leptin level was significantly higher (3.182+/-0.936 ng/ml) than the value before the operation (0.818+/-0.242 ng/ml). This fluctuation of serum leptin level caused by ovariectomy was eliminated by the replacement of estrogen. The present data indicate that ovariectomy-induced weight gain is caused by the early drop in leptin level. The later rise in leptin production is connected to the increased body weight probably originated from a reduced sensitivity in leptin signal.

Animals↗

PubMed1999

Markers of cell proliferation and expression of melanosomal antigen in lymphangioleiomyomatosis.

Pulmonary lymphangioleiomyomatosis (LAM), a disease of young women, is characterized by proliferation of immature-appearing smooth-muscle cells (LAM cells) in the lungs and abdomen. LAM cells react with monoclonal antibody HMB45, which recognizes a 100-kD glycoprotein (gp100) originally found in human melanoma cells. We investigated the expression and the subcellular localization of gp100 in lung tissue from patients with LAM and in human melanoma cell lines (Malme-3M, A2058, and CHL-1), and the relationship between this expression and cellular proliferation. Binding sites for HMB45 antibody in melanoma and LAM cells were located in cytoplasmic granules resembling immature melanosomes. LAM cells reactive for proliferating-cell nuclear antigen (PCNA), a marker of cellular proliferation, were spindle-shaped, in contrast to the large, epithelioid cells reacting with HMB45 antibody. In accord with this finding, we observed an inverse relationship between the immunostaining for HMB45 antibody and PCNA in LAM and melanoma cells. Thus, LAM and melanoma cells are heterogeneous with respect to their stages of proliferation and their expression of melanoma antigens. PCNA-positive cells, which are more likely to be negative for reactivity with HMB45 antibody, may be more relevant to the progression of LAM than are HMB45-positive cells, which are the hallmark of LAM.

Actins↗

PubMed1999

Comprehensive evaluation of 35 patients with lymphangioleiomyomatosis.

OBJECTIVES: To evaluate comprehensively the characteristics of lymphangioleiomyomatosis (LAM), with emphasis on the application of imaging and immunohistochemical methods. DESIGN: Prospective study. PATIENTS: Thirty-five female subjects with LAM. SETTING: Clinical Center, National Institutes of Health. INTERVENTIONS: BAL, pulmonary function test, ventilation/perfusion lung scans, CT of the chest and abdomen, ultrasonography of abdomen, and immunohistochemical study of lung biopsy specimens. RESULTS: Most patients had exertional dyspnea (83%) and pneumothorax (69%). BAL did not show diagnostic changes. The most common abnormalities on pulmonary function tests were decreased diffusing capacity of carbon monoxide (83%), hypoxemia (57%), and airway obstruction (51%). Bronchodilator response was found in 26% of patients. CT, which is almost pathognomonic, showed numerous thin-walled cysts throughout both lungs in all patients. Thirty-four patients (97%) had abnormal ventilation and/or perfusion lung scans. An unusual "speckling" pattern was observed on ventilation scans of 74% of patients. Common extrapulmonary features were retroperitoneal adenopathy (77%) and renal angiomyolipomas (60%). The percentage of abnormal smooth muscle cells (LAM cells), reactive with HMB45, varied from 17 to 67% in 10 lung biopsy specimens. CONCLUSIONS: Improved diagnostic methods have defined the abnormalities in patients with pulmonary LAM and increased the potential for early recognition and treatment of this disorder. Patients with LAM should be evaluated for bronchodilator responsiveness and may benefit from a trial of bronchodilators.

Abdomen↗

PubMed1998

Cytokine-mediated transcriptional induction of the human inducible nitric oxide synthase gene requires both activator protein 1 and nuclear factor kappaB-binding sites.

The involvement of AP-1 and NF-kappaB transcription factors in cytokine-mediated induction of human inducible nitric oxide synthase (hiNOS) promoter activity was examined. Luciferase reporter plasmids, containing mutations in AP-1 and NF-kappaB sites, in a hiNOS promoter extending from -8.3 kilobase pairs (kb) to +168, were transiently expressed in A549 cells, and promoter activity was determined after treatment with a cytokine mixture (CM) containing interleukin 1-beta, interferon-gamma, and tumor necrosis factor-alpha. Mutation of the AP-1 heptad located -5301 base pairs upstream decreased gene activation by 90% in a -8.3-kb promoter and a shorter -5.574-kb promoter. Disruption of AP-1 (at -5115) or NF-kappaB (at -115 and -8283) sites reduced promoter activity by 45, 67, and 52%, respectively. Responsiveness to CM was decreased by 85% in constructs mutated in both NF-kappaB sites. By gel retardation analyses, CM increased AP-1- and NF-kappaB binding. Supershift analysis identified Jun D and Fra-2 as components of AP-1 complexes. Each kappaB site bound different complements of NF-kappaB/Rel family members (downstream site, Rel A/p50; upstream site, Rel A/Rel A). Rel A was maximally, whereas IkappaB-alpha was minimally, expressed in nuclei after 1 h of CM treatment, corresponding with the peak in NF-kappaB inding activity. Thus, AP-1 and NF-kappaB are important cis-elements for induction of hiNOS gene transcription.

Amino Acid Sequence↗

PubMed1998

Analysis of the cytokine-stimulated human inducible nitric oxide synthase (iNOS) gene: characterization of differences between human and mouse iNOS promoters.

Expression of human inducible nitric oxide synthase (hiNOS) is under cytokine control and is transcriptionally regulated. The hiNOS and mouse iNOS (miNOS) genes are regulated differently by cytokines. To understand better the transcriptional regulation of the hiNOS gene, the 8.3-kb hiNOS promoter was characterized. Promoter activity was evaluated by transient transfection of hiNOS luciferase constructs in A549 human alveolar type II epithelium-like cells in the presence and absence of cytokines (IFN-gamma, IL-1 beta, and TNF-alpha). Important cytokine-responsive elements are located at -3665 to -5574 bp (containing two perfectly matched AP-1 sites which are not present in miNOS promoter) and -8093 to -8296 bp (one perfectly matched NF-kappa B site) of the hiNOS promoter region. Likely, these two AP-1 sites and the upstream NF-kappa B site are important in the transcriptional induction of hiNOS by cytokines. Our data demonstrate the molecular basis for the different cytokine-stimulated characteristics of hiNOS and miNOS genes.

Animals↗

PubMed1998

Immunohistochemical analysis of proteins of the Bcl-2 family in pulmonary lymphangioleiomyomatosis: association of Bcl-2 expression with hormone receptor status.

BACKGROUND: Pulmonary lymphangioleiomyomatosis (LAM), a disease of young women, is characterized by proliferation of abnormal smooth muscle cells (LAM cells), which often differ from normal pulmonary smooth muscle cells by frequently having estrogen and progesterone receptors. OBJECTIVE: To evaluate the relationships among several factors related to proliferation and apoptosis in LAM cells, we employed immunohistochemical methods for the localization of Bcl-2 and Mcl-1 (inhibitors of apoptosis), Bax (a promoter of apoptosis), c-Myc (an apoptosis-related oncoprotein), proliferating cell nuclear antigen (an indicator of mitotic activity), and nick end labeling (to identify apoptotic cells) in lung tissues of 9 patients with LAM. RESULTS: In all patients, most LAM cells reacted positively for Bax. The LAM cells were positive for both Bcl-2 and estrogen receptor in 5 patients, positive for only Bcl-2 in 1 patient, positive for only estrogen receptor in another patient, and negative for both in 2 patients. More than 50% of the Bcl-2-positive LAM cells were also positive for estrogen receptor. The reaction for c-Myc was positive in all patients. The immunoreactivity for Bcl-2 and Mcl-1, which inhibit apoptosis, was more intense in LAM cells than in normal vascular and bronchial smooth muscle cells. In 6 patients, more than 50% of the LAM cells were positive for proliferating cell nuclear antigen. Apoptosis was infrequent in LAM cells. CONCLUSIONS: Our results suggest that the expression of Bcl-2 in LAM cells may be related to hormonal regulation, and that by decreasing apoptosis, Bcl-2 and related proteins contribute to the imbalance between proliferation and death of LAM cells.

Adult↗

PubMed1997

Proteolytic activities of mouse sarcoma 180 cells that are inhibited by Bowman-Birk and Kunitz protease inhibitors.

In this study, using zymogram analysis two proteolytic activities were identified in the mouse sarcoma 180 (S-180) cells that were activated by trypsin treatment and inhibited by both BBI and ACTI. These enzymes, with molecular weights of 46 kDa (dominant band) and 62 kDa (minor band), were mainly localized in the cytosol, and had optimal activity at pH 7 and 8 respectively. Their inhibition by DFP, BBI and ACTI but not EDTA and TPCK indicated they were trypsin-like serine proteases and may be the intracellular target-enzymes of protease inhibitors. The level of the precursor of the 62 kDa protease was significantly increased in the S-180 solid and soft tumors, whereas the level of the 46 kDa precursor was almost undetectable, implying that a physiological role may be played by these serine proteases during tumor invasion.

Animals↗

PubMed1997

Database issues in object-oriented clinical information systems design.

A clinical information system (CIS) prototype was created from an Object-Oriented (OO) design. We experienced considerable difficulties when implementing the OO data model in a relational database management system (RDBMS), including lack of semantic power and support for complex objects, inability to encapsulate object methods, and performance degradation due to extensive join operations. This paper reflects on the experiences of a CIS research project and explores issues related to the use of RDBMS and Object-Oriented Database Management Systems (OODBMS) in CIS design and development.

Database Management Systems↗

PubMed1996

Alternative splicing of human inducible nitric-oxide synthase mRNA. tissue-specific regulation and induction by cytokines.

Human inducible nitric-oxide synthase (iNOS) is responsible for nitric oxide synthesis in response to inflammatory mediators. The human iNOS gene, containing 26 exons, encodes a protein of 131 kDa. This study was aimed at investigating the presence of alternative splicing of human iNOS mRNA. Total RNA from human alveolar macrophages, nasal and bronchial epithelial cells, and several human tissues was transcribed to cDNA and analyzed using polymerase chain reaction with specific primers for segmental analysis of the iNOS gene. Four sites of alternative splicing were identified by sequence analysis; these included deletion of: (i) exon 5; (ii) exons 8 and 9; (iii) exons 9, 10, and 11; and (iv) exons 15 and 16. The deduced amino acid sequences of the novel iNOS cDNAs predict one truncated protein (resulting from exon 5 deletion) and three iNOS proteins with in-frame deletions. Southern analyses of polymerase chain reaction products were consistent with tissue-specific regulation of alternative splicing. In cultured cells, iNOS induction by cytokines and lipopolysaccharide was associated with an increase in alternatively spliced mRNA transcripts. Because iNOS is active as a dimer, the novel forms of alternatively spliced iNOS may be involved in regulation of nitric oxide synthesis.

Alternative Splicing↗

PubMed1995

Structural diversity in the 5'-untranslated region of cytokine-stimulated human inducible nitric oxide synthase mRNA.

Inducible nitric oxide synthase, the critical enzyme responsible for the enhanced synthesis of nitric oxide in inflammatory states, is widely expressed in mammalian cells. To evaluate potential regulatory roles of the 5'-untranslated region (UTR) in the human inducible nitric oxide synthase gene, the transcription initiation sites and structure of the 5'-UTR of human inducible nitric oxide synthase were examined. Freshly isolated human alveolar macrophages, bronchial epithelial cells, and several types of cultured cells were evaluated following stimulation with cytokines (i.e. interferon-gamma, interleukin-1 beta, tumor necrosis factor-alpha, and interleukin-6). The mRNA was analyzed by reverse transcription-polymerase chain reaction. Northern analysis, and 5'-rapid amplification of cDNA ends. Despite the presence of a TATA box in the promoter region, multiple transcription initiation sites were observed, some extending several hundred base pairs upstream from the main TATA-directed initiation site. Alternative splicing in the 5'-UTR of human inducible nitric oxide synthase mRNA resulted in further diversity. The TATA-independent inducible nitric oxide synthase mRNA transcripts were up-regulated by cytokines. The long and complex 5'-UTRs contain eight partially overlapping open reading frames upstream of the putative inducible nitric oxide synthase ATG, which may have an important role in translational regulation of human inducible nitric oxide synthase mRNA.

Alternative Splicing↗

PubMed1995

Cellular proteins specifically bind to the 5'-noncoding region of hepatitis C virus RNA.

Hepatitis C virus (HCV) RNA contains a highly conserved 5'-noncoding region (5'NCR) which may be important in viral multiplication. To study the possible mechanisms of the cellular proteins involved in HCV replication and pathogenesis, a gel mobility shift assay and competition analysis were performed with the HCV 5'NCR. Two specific complexes were formed between the 341-nucleotide RNA of the HCV 5'NCR and proteins of mammalian cells. The specific RNA-protein complexes were maintained in the region of the 5'NCR from nucleotides 131 to 253. Nevertheless, the slower migrating RNA-protein complex failed to form when a polypyrimidine tract sequence (191-UCCUUUCUU-199) in the stem-loop III structure of HCV 5'NCR was changed to 191-UCCUUUggU-199. A uv cross-linking assay further identified two cellular proteins, p87 and p120, that specifically bound to the stem-loop III structure. Mutations at the polypyrimidine tract sequence inhibited the binding of p87, but maintained the ability of the mutant HCV RNA to interact with p120. Translation competition assay demonstrated that the 5'NCR from nt 131 to 253 within the stem-loop III structure is important for the translation of HCV core protein. In addition, p120 and unidentified cellular proteins are likely to be involved in the translation of HCV polyprotein, whereas p87 may play important roles in HCV multiplication other than translation.

Animals↗

PubMed1995

[Analysis of 117 cases of hypospadias--its location, operation and complication].

Hypospadias is a common congenital anomaly in male newborns. The incidence is about one in 300 live male births. In the U.S., about 6000 boys with hypospadias are born each year. For this study, we collected 117 recent (with the last 5 years) cases (88 fresh and 29 referred) who received an operation in our department. We calculated the hypospadias location and the complication rate with the desire of finding out the relationships between them. Our overall complication rate is 51.3% which is much higher than other recent studies and may be related to a different distribution of the hypospadias locations.

Adolescent↗

PubMed1995

A study on the impact of database design on clinical information systems.

This paper reports on a research project which aims at addressing one of the most crucial problems in clinical computing--the relation between clinical data and database design and their impacts on Clinical Information Systems. The discussion will focus on a research project that is currently being conducted in a number of acute care hospitals at Melbourne, Australia to investigate the database design for the Emergency Department Information System (EDIS), a subset of the Clinical Information System (CIS).

Australia↗

PubMed1994

A new crystal form of abrin-a from the seeds of Abrus precatorius.

A new crystal form of abrin-a from the seeds of Abrus precatorius has been obtained by vapor diffusion method. The abrin-a crystals belong to monoclinic space group P2(1) with cell dimensions a = 84.58 A, b = 73.07 A, c = 48.23 A, beta = 96.20 degrees. An asymmetric unit contains one protein molecule of molecular weight 65 kDa and has a solvent content of approximately 46%.

Abrin↗

PubMed1994

Functional status of pancreatic islet in acute leukemia.

Using enzymatic assay and radioimmunoassay, we studied the functional status of pancreatic islet in 50 patients with acute leukemia. Oral glucose tolerance test and insulin and C peptide release were made in 40 patients before and after treatment. 14 patients who revealed diabetic curve and delayed insulin and C peptide release before treatment showed normal values in 6 after therapy. Five patients with impaired glucose tolerance and decreased insulin and C peptide release before treatment showed normalization of these parameters following therapy. Five patients with normal pretreatment values disclosed abnormal post-treatment results. The remaining 16 patients displayed normal results both before and after therapy. Anti-insulin antibodies were negative, and glucagon level was normal in all the 50 patients. The red cell insulin receptor binding rate analysed in 47 patients was significantly higher than in controls (P < 0.001). We considered that the disturbed glucose metabolism in acute leukemia was not uncommon mainly due to the dysfunction of pancreatic islet beta cells as a result of islet damage by leukemic cells, the effect of corticosteroid and chemotherapy and the preexisting diabetes. Impaired glucose metabolism had no influence on therapeutic effect.

Adolescent↗