Biomedical subjects

F C Kuo

Publications and source records attributed to F C Kuo.

9 recordsLinked to original sources

PubMed2006

Interaction between cigarette, alcohol and betel nut use on esophageal cancer risk in Taiwan.

OBJECTIVE: In 2003 esophageal cancer was the sixth leading cause of death among men in Taiwan, but it is the fastest increasing (70%) alimentary tract cancer. The aim of this study was to investigate the impact of different habits of betel nut chewing on esophageal squamous cell carcinoma (SCC) and its interaction with cigarette use and alcohol consumption. MATERIALS AND METHODS: All 165 cases were pathologically proven esophageal SCC patients (all male, mean age = 56.0, range = 35-92 years) diagnosed by biopsy during gastroendoscopic examinations. The control group comprised 255 subjects (all male, mean age = 54.8, range = 40-92 years) selected from patients who had visited the Otolaryngology Outpatient or Inpatient Department of KMUH owing to a benign lesion over this field. All were interviewed to collect demographic and substance use information by a trained interviewer using a standardized questionnaire. RESULTS: Smoking (aOR = 5.4, 95% CI = 2.4-12.9, PAR = 72%), alcoholic beverage drinking (aOR = 17.6, 95% CI = 9.3-35.2, PAR = 76%) and low education level are independent risk factors for esophageal cancer. Although betel nut chewers only had a borderline significant higher risk than nonchewers (aOR = 1.7; 95% CI = 0.8-3.1), those who chewed with a piece of betel inflorescence (aOR = 4.2, 95% CI = 1.4-16.0) and swallow betel-quid juice (aOR = 3.3, 95% CI = 1.3-9.3) had a significant higher risk. Significant dose-response effects were found in daily quantity of drinking and smoking. There is a synergistic effect of these three substances on the development of esophageal cancer. CONCLUSION: Betel nut chewing plays a relevant role in the development of esophageal SCC but adds to the carcinogenetic effect of smoking and alcohol drinking. Direct mucosal contact of betel juice may contribute to its carcinogenesis.

Adult↗

PubMed2001

Frequent fusion of the JAZF1 and JJAZ1 genes in endometrial stromal tumors.

Endometrial stromal tumors are divided into three types: benign stromal nodules, endometrial stromal sarcomas, and undifferentiated endometrial sarcomas. A variety of cytogenetic abnormalities involving chromosome 7 have been reported in endometrial stromal sarcomas, including a recurrent t(7;17)(p15;q21). We have identified two zinc finger genes, which we have termed JAZF1 and JJAZ1, at the sites of the 7p15 and 17q21 breakpoints. Analyses of tumor RNA indicate that a JAZF1/JJAZ1 fusion is present in all types of endometrial stromal tumors; however, the fusion appears to be rarer among endometrial stromal sarcomas that would be considered high-grade according to certain classification schemes. These findings suggest that the less malignant endometrial stromal tumors may evolve toward more malignant types, but that some endometrial stromal sarcomas with relatively abundant mitotic activity may compose a biologically distinct group.

Amino Acid Sequence↗

PubMed2000

Importance of replication in microarray gene expression studies: statistical methods and evidence from repetitive cDNA hybridizations.

We present statistical methods for analyzing replicated cDNA microarray expression data and report the results of a controlled experiment. The study was conducted to investigate inherent variability in gene expression data and the extent to which replication in an experiment produces more consistent and reliable findings. We introduce a statistical model to describe the probability that mRNA is contained in the target sample tissue, converted to probe, and ultimately detected on the slide. We also introduce a method to analyze the combined data from all replicates. Of the 288 genes considered in this controlled experiment, 32 would be expected to produce strong hybridization signals because of the known presence of repetitive sequences within them. Results based on individual replicates, however, show that there are 55, 36, and 58 highly expressed genes in replicates 1, 2, and 3, respectively. On the other hand, an analysis by using the combined data from all 3 replicates reveals that only 2 of the 288 genes are incorrectly classified as expressed. Our experiment shows that any single microarray output is subject to substantial variability. By pooling data from replicates, we can provide a more reliable analysis of gene expression data. Therefore, we conclude that designing experiments with replications will greatly reduce misclassification rates. We recommend that at least three replicates be used in designing experiments by using cDNA microarrays, particularly when gene expression data from single specimens are being analyzed.

DNA, Complementary↗

PubMed2000

Potent fibrinolytic enzyme from a mutant of Bacillus subtilis IMR-NK1.

A mutant of Bacillus subtilis IMR-NK1, which is used for the production of domestic "natto" in Taiwan, produced high fibrinolytic enzyme activity by solid-state fermentation using wheat bran as medium. In addition, a strong fibrinolytic enzyme was purified from the cultivation media. The purified enzyme was almost homogeneous, as examined by SDS-PAGE and capillary electrophoresis. The enzyme had an optimal pH of 7.8, an optimal temperature of 55 degrees C, and a K(m) of 0.15% for fibrin hydrolysis. The molecular mass estimated by gel filtration was 31.5 kDa, and the isoelectric point estimated by isoelectric focusing electrophoresis was 8.3. The enzyme also showed activity for hydrolysis of fibrinogen, casein, and several synthetic substrates. Among the synthetic substrates, the most sensitive substrate was N-succinyl-Ala-Ala-Pro-Phe-pNA. PMSF and NBS almost completely inhibited the activity of the enzyme. These results indicate that the enzyme is a subtilisin-like serine protease, similar to nattokinase from Bacillus natto.

Bacillus subtilis↗

PubMed1997

Augmented expression of a human gene for 8-oxoguanine DNA glycosylase (MutM) in B lymphocytes of the dark zone in lymph node germinal centers.

B cells that mediate normal, T cell-dependent, humoral immune responses must first pass through germinal centers (GCs) within the cortex of antigenically stimulated lymph nodes. As they move through the dark zone and then the light zone in the GC, B cells are subjected to somatic hypermutation and switch recombination within their rearranged immunoglobulin genes and also participate in a number of other processes that control development into memory cells or cells specialized for antibody secretion. To investigate the molecular mechanisms that contribute to B cell development within GCs, we constructed a recombinant DNA library enriched for cDNAs derived from human genes expressed in B cells at this site. This library was found to contain a cDNA structurally and functionally related to genes in bacteria and yeast for the DNA repair enzyme 8-oxoguanine DNA glycosylase. Northern blot analysis indicated that the human gene is expressed as two alternatively spliced messenger RNAs within GC B cells at levels greatly exceeding that found in other tissues. In situ hybridization studies revealed that expression of this gene is most abundant within the dark zones of GCs. Both the function and localized expression of this gene suggest that it may play a role in somatic hypermutation of immunoglobulin genes.

Amino Acid Sequence↗

PubMed1996

Diffuse colonic mantle cell lymphoma in a patient with presumed ulcerative colitis: detection of a precursor monoclonal lymphoid population using polymerase chain reaction and immunohistochemistry.

Primary lymphoma of the colon, a rare and typically late complication of ulcerative colitis, exhibits high-grade morphology and behavior when it occurs. Recently, several reports of colonic lymphoma masquerading as ulcerative colitis have been described. These previous reports described inflammatory mucosal changes typical of ulcerative colitis as being present in superficial biopsies, leading to the initial diagnosis of ulcerative colitis; however, further workup resulted in a diagnosis of primary colonic lymphoma within several months in these cases, and all symptoms and mucosal changes resolved after treatment of the lymphoma. Herein we report a case of mantle cell lymphoma arising in the colon and rectum in a 71-year-old woman with a 4-year history of ulcerative colitis. Immunoglobulin heavy-chain gene rearrangements were detected using the polymerase chain reaction procedure in fixed tissue in the lymphoma as well as in a prior resection specimen that histologically appeared to show only changes of severe ulcerative colitis. This finding suggests that an indolent lymphoid proliferation may have been the underlying disease in this patient and raises questions about the role of colonic lymphoma in causing mucosal injury.

Aged↗

PubMed1994

An early haematopoietic defect in mice lacking the transcription factor GATA-2.

Blood cell development relies on the expansion and maintenance of haematopoietic stem and progenitor cells in the embryo. By gene targeting in mouse embryonic stem cells, we demonstrate that the transcription factor GATA-2 plays a critical role in haematopoiesis, particularly of an adult type. We propose that GATA-2 regulates genes controlling growth factor responsiveness or the proliferative capacity of early haematopoietic cells.

Anemia↗

PubMed1991

Colocalization in pericentral hepatocytes in adult mice and similarity in developmental expression pattern of ornithine aminotransferase and glutamine synthetase mRNA.

In situ hybridization showed that the mRNA for ornithine aminotransferase (OAT; ornithine-oxo-acid aminotransferase; L-ornithine: 2-oxo-acid aminotransferase, EC 2.6.1.13) colocalized with glutamine synthetase [GS; glutamate-ammonia ligase; L-glutamate: ammonia ligase (ADP-forming), EC 6.3.1.2] in pericentral hepatocytes of the adult mouse liver. In addition to an identical distribution in adult hepatocytes, OAT and GS have very similar expression patterns in fetal and neonatal liver. As was earlier described for GS, there is a low level of OAT mRNA in fetal cells and increasing pericentral levels in neonates that reach adult patterns within 2 weeks. These results suggest that the transcriptional regulation of the two genes is similar in the liver. However, there was a lack of colocalization of the mRNAs for the two enzymes in cells of the kidney, intestine, and brain, suggesting different regulatory decisions for the OAT and GS genes in the cells of these different tissues. The metabolic consequences of these localized expression patterns favor ammonia clearance from the blood by the liver and urea synthesis by the kidney.

Age Factors↗

PubMed1991

Evidence that interaction of hepatocytes with the collecting (hepatic) veins triggers position-specific transcription of the glutamine synthetase and ornithine aminotransferase genes in the mouse liver.

We previously demonstrated that glutamine synthetase (GS) and ornithine aminotransferase (OAT) mRNAs are expressed in the mouse liver acinus preferentially in pericentral hepatocytes, that is, those immediately surrounding terminal central veins (A.L. Bennett, K.E. Paulson, R.E. Miller, and J.E. Darnell, Jr., J. Cell Biol. 105:1073-1085, 1987, and F.C. Kuo, W.L. Hwu, D. Valle, and J.E. Darnell, Jr., Proc. Natl. Acad. Sci. USA, in press). We now show that hepatocytes surrounding large collecting hepatic veins but not portal veins also express these two mRNAs. The pericentral hepatocytes are the most distal hepatocytes with respect to acinar blood flow, whereas this is not necessarily the case for hepatocytes next to the large collecting hepatic veins. This result implies that it is contact with some hepatic venous element which signals positional expression. In an effort to induce conditions that change relationships between hepatocytes and blood vessels, regenerating liver was studied. After surgical removal of two-thirds or more of the liver, there was no noticeable change in GS or OAT expression in the remaining liver tissue during regeneration. However, treatment with carbon tetrachloride (CCl4), which specifically kills pericentral hepatocytes, completely removed GS- and OAT-containing cells and promptly halted hepatic transcription of GS. Repair of CCl4 damage is associated with invasion of inflammatory and scavenging cells, which remove dead hepatocytes to allow regrowth. Only when hepatocytes resumed contact with pericentral veins were the pretreatment levels of OAT and GS mRNA and high levels of GS transcription restored.

Animals↗