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Biomedical subjects

K C Chow

Publications and source records attributed to K C Chow.

At least 19 recordsLinked to original sources
PubMed2002

Effects of platelet activating factor, butyrate and interleukin-6 on cyclooxygenase-2 expression in human esophageal cancer cells.

BACKGROUND: Epidemiological studies have indicated that non-steroidal anti-inflammatory drugs (NSAIDs) can reduce the risk of esophageal squamous cell carcinoma (ESCC) by taking cyclooxygenase (COX) as the target enzyme. The pathophysiological regulation of COX-2 may play a role in carcinogenesis and in disease progression of esophageal carcinoma. METHODS: 59 ESCC samples were used to assess COX-2 expression in the tumor cells and four ESCC cell lines to investigate the effects of phorbol myristate acetate (PMA), platelet activating factor (PAF), n-sodium butyrate (n-BT) and interleukin-6 (IL-6) on the expression of COX-2. Expression of COX-2 was determined by immunohistochemistry (IHC) and reverse transcription-polymerase chain reaction (RT-PCR). Production of PGE2 was measured by a competitive enzyme immunoassay (CEIA). RESULTS: COX-2 expression was detected in 54.2% (32/59) of the pathological sections by IHC. COX-2 expression in ESCC cells was significantly increased following treatment with PAF and n-BT. Increased production of PGE2 was detected in the culture media, and the secreted PGE2 in the culture media was proportional to the increased COX-2 expression. The addition of IL-6 could also enhance COX-2 expression in ESCC cells. While NSAIDs could inhibit enzymatic activity of COX-2, they did not inhibit COX-2 gene expression in ESCC cells. PKC inhibitor, however, could abrogate PMA-induced COX-2 gene expression, but it did not block IL-6-induced COX-2 expression. CONCLUSIONS: Our data suggest that COX-2 expression in ESCC cells could be upregulated by PMA, PAF, n-BT and IL-6. Nonetheless, IL-6-induced COX-2 expression could be independent of PKC activation.

Adolescent↗
PubMed2001

Overexpression of dihydrodiol dehydrogenase as a prognostic marker of non-small cell lung cancer.

By using mRNA differential display to examine specimens of non-small cell lung cancer (NSCLC), we have identified overexpression of dihydrodiol dehydrogenase (DDH) that was not detected in the corresponding normal lung tissue. Normally DDH is associated with catalysis of polycyclic aromatic hydrocarbons (PAHs) in the liver; in NSCLC cells, DDH expression would implicate an association with disease progression. In this study we investigated the prognostic significance of DDH expression in patients with NSCLC. By using immunohistochemistry, we measured DDH expression in 381 patients with NSCLC. The relationship between DDH expression and clinicopathological parameters (age, gender, smoking history, mitotic index, histological type, stage, cell differentiation, and lymphovascular invasion) was analyzed by chi2 analysis. Survival curves were plotted with the method of Kaplan-Meier, and statistical difference of survivals between different groups was compared by a log-rank test. Our results showed that DDH overexpression could be detected in 317 (83.2%) of 381 pathological sections and in 77.9% (60 of 77) of metastatic lymph nodes. Expression of DDH was confirmed by immunoblotting. Compared with patients with DDH overexpression in tumors, patients with low DDH expression had significantly lower incidence of early tumor recurrence and distant organ metastasis (46.7 versus 29.7%; P = 0.045). Interestingly, survival was also significantly better in patients with low DDH expression than in those with DDH overexpression (P = 0.0017). Using univariate analysis, we correlated three important factors, DDH overexpression, tumor stages, and gender, with poor prognosis for NSCLC patients. Nevertheless, biological function and involvement of DDH in the disease progression of NSCLC require additional studies.

Adult↗
PubMed2001

Magnetic field exposure induces DNA degradation.

In our earlier experiments, we discovered that magnetic field exposure could bring both stabilizing and destabilizing effects to the DNA of Escherichia coli, depending on our parameters of assessment, and both of these effects were associated with the induced synthesis of the heat shock proteins Hsp70/Hsp40 (DnaK/DnaJ). These contradicting results prompted us to explore in this study the effect of magnetic field exposure on the DNA stability in vivo when the heat shock response of the cell was suppressed. By using plasmid pUC18 in E. coli as the indicator, we found that without the protection of the heat shock response, magnetic field exposure indeed induced DNA degradation and this deleterious effect could be diminished by the presence of an antioxidant, Trolox C. In our in vitro test, we also showed that the magnetic field could potentiate the activity of oxidant radicals.

Antioxidants↗
PubMed2001

Detection of cytomegalovirus infection in a patient with febrile ulceronecrotic Mucha-Habermann's disease.

BACKGROUND: Febrile ulceronecrotic Mucha-Habermann's disease (FUMHD) is a severe and very rare variant of pityriasis lichenoides et varilioformis acuta, which is characterized by large coalescing, and ulceronecrotic maculopapules or plaques. Morphological changes of the skin accompanied by persistent high fever and several constitutional symptoms have suggested virus infection in patients with FUMHD. However, the available information of viral origin is limited. In this study we investigated the relationship of cytomegalovirus (CMV), Epstein-Barr virus (EBV), human herpesvirus 8 (HHV8), type I human T-cell lymphotropic virus (HTLV-I), and parvovirus B19 (PVB19) with FUMHD in a Taiwanese patient. METHODS: The existence of CMV, EBV, HHV8, HTLV-I, and PVB19 was determined by polymerase chain reaction (PCR). The presence of CMV in the endothelial cells was characterized by in situ hybridization (ISH) and immunohistochemistry (IHC). RESULTS: Serologic immunoglobulin to CMV and IHC identification of CMV late gene in the biopsy specimen indicated that the patient was infected with CMV. Detection of CMV was confirmed by PCR and ISH. CONCLUSIONS: These results indicate that FUMHD is associated with dermal CMV manifestation. Nonetheless, the induction mechanism of FUMHD with CMV infection has yet to be determined.

Acyclovir↗
PubMed2001

Repeated intestinal perforation caused by an incomplete form of Behçet's syndrome.

Behçet's disease, as initially described, is a triad of recurrent oral and genital ulcers and relapsing uveitis. The incomplete form, in which there is no ocular involvement, has been described in Japan and Korea, but this is not commonly recognized in the southern Chinese. We reported herein a rare case of repeated intestinal perforations caused by an incomplete form of Behçet's syndrome in a southern Chinese man.

Aged↗
PubMed2001

Phase II trial of systemic recombinant interleukin-2 in the treatment of refractory nasopharyngeal carcinoma.

BACKGROUND: Interleukin-2 (IL-2) is a cytokine produced by activated T cells, which has shown powerful immunostimulatory and antineoplastic properties. Nasopharyngeal carcinoma (NPC) is an Epstein-Barr virus-associated cancer with abundant lymphocyte infiltration histologically. The activity of IL-2 in the treatment of NPC patients is currently unknown. A phase II study was, therefore, initiated to evaluate the efficacy, toxicity and immunological consequences of intravenous bolus IL-2 in patients with recurrent/metastatic NPC. METHODS: Between November 1996 and April 1997, 14 patients with recurrent/metastatic NPC were entered into the study. Recombinant IL-2 (Proleukin, Chiron) was injected by intravenous bolus every 8 h at 72,000 IU/kg for a maximum of 15 doses. After 7 days, patients were retreated with a second identical cycle of therapy. Those patients who were stable or responding to treatment 5-6 weeks later went on to receive another course (two cycles) of therapy. All patients received prophylactic antibiotics and antipyretic medicine. Response and toxicities were evaluated. Serial plasma level of TNF-alpha, IL-6, soluble IL-2 receptor, IL-10 and soluble CD8 were determined. RESULTS: Fourteen patients received a total of 34 cycles of therapy. No response was observed. Fifty percent had stable disease, 50% had progressive disease after a median of two cycles of therapy. There was one treatment-related death from acute myocardial infarction. Body weight increase (>5%) occurred in 80% of cycles, and hypotension (BP <80 mm Hg systolic) occurred in 53%. Serum creatinine increase (>2 mg%) occurred in 24% of cycles, and SGOT/SGPT increase (>3x) in 10% of cycles. Symptoms of somnolence, general malaise, nausea and vomiting, pruritus, xerostomia, desquamation were generally mild to moderate but rapidly reversible. CONCLUSION: The single modality of intravenous bolus IL-2 at the dose level of 72,000 IU/kg is clinically ineffective in NPC patients. Potential mechanisms of the ineffectiveness of IL-2 therapy on NPC patients are discussed.

Adult↗
PubMed2001

Effect of platelet activating factor and butyrate on the expression of interleukin-2 receptor alpha in nasopharyngeal carcinoma cells.

Serum level of soluble interleukin-2 receptor alpha (sIL-2Ralpha) has been shown to correlate with disease progression and prognosis of cancer patients. However, the available information about the source and the pathophysiological regulation of IL-2Ralpha in cancer cells is limited. This study addressed the questions of prognostic value and the source of sIL-2Ralpha in patients with nasopharyngeal carcinoma (NPC). Biological regulation of IL-2Ralpha was characterized in NPC cell lines. Serum sIL-2Ralpha levels of 113 NPC patients were measured by enzyme-linked immunosorbent assay (ELISA). Levels of sIL-2Ralpha in NPC patients were significantly higher than that in the healthy controls, and sIL-2Ralpha levels were correlated with disease progression and patient survival. IL-2Ralpha was identified in cancer cells by immunocytochemistry. In vitro, IL-2Ralpha expression was markedly increased following treatment with platelet activating factor and/or n-sodium butyrate. Increased secretion of IL-2Ralpha was also detected in the culture media. The secreted IL-2Ralpha could functionally bind IL-2. These results indicate that elevated sIL-2Ralpha was often detected in patients with advanced NPC. The elevated sIL-2Ralpha could be shed from NPC cells by a yet to be determined mechanism and IL-2Ralpha expression in NPC cells could be upregulated by platelet activating factor and butyrate.

Adult↗
PubMed2000

Congenital enterovirus 71 infection: a case study with virology and immunohistochemistry.

Previously reported enterovirus 71 (EV71) infections associated with hand-foot-mouth disease, aseptic meningitis, encephalitis, polio-like myelitis, and paralysis all have involved young children. We report a 28-year-old woman who possibly contracted EV71 infection during pregnancy. Obstetric ultrasonograms at 25 weeks of gestation revealed an abnormal placenta, as well as hepatosplenomegaly, liver calcification, excessive ascites, and mild hydrocephalus of the fetus. Presence of EV71 was determined by immunodot blotting, virus culture, and partial sequencing of the amplified product of nested reverse transcription-polymerase chain reaction. Postmortem immunohistochemistry further identified EV71 in the fetal midbrain and liver. The findings indicate that intrauterine EV71 infection is possible during pregnancy.

Adult↗
PubMed2000

Magnetic field exposure stimulates transposition through the induction of DnaK/J synthesis.

Like some naturally occurring environmental stress factors such as heat shock and UV irradiation, magnetic field exposure is also stimulatory to transposition activity. This feature could be illustrated by a bacterial conjugation study using an Escherichia coli strain that carries the transposable element Tn5 as the donor. When the donor cultures were exposed to a low-frequency (50 Hz) magnetic field of 1.2 mT, Tn5 located on the bacterial chromosome was stimulated to transpose and settled on the extrachromosomal episome, and eventually transferred to the recipient cell through conjugation. Such transposition activity stimulation was mediated by the induced synthesis and accumulation of the heat shock proteins DnaK/J.

Bacterial Proteins↗
PubMed2000

Expression of fas ligand on bile ductule epithelium in biliary atresia--a poor prognostic factor.

PURPOSE: The aim of this study was to investigate the possible role of Fas and Fas ligand system in biliary atresia. METHODS: Immunohistochemical stains of Fas and Fas ligand (FasL) and in situ hybridization of Fas ligand messenger RNA (mRNA) were performed on paraffin-embedded liver specimens of 36 biliary atresia, 6 choledochal cysts, and 14 nontumorous parts of pediatric liver tumors. Apoptosis was detected by terminal deoxynucleotidyl transferase deoxy-UTP nick end labeling (TUNEL). The grade of liver fibrosis and results of bile drainage on the patients with biliary atresia were compared with the results of FasL expression. RESULTS: Fas protein was positive on the hepatocytes and bile ductule epithelia of all the livers examined and also positive on some monocytes around the portal area in all the biliary atresia patients. FasL protein was positive on bile ductule epithelia in 10 biliary atresia patients and also positive on some monocytes in most of the biliary atresia patients. Positive signals of FasL mRNA were noted on hepatocytes in 4 biliary atresia, bile ductule epithelia in 19 biliary atresia patients, and some monocytes in most of the biliary atresia patients. Apoptotic nuclei were present among monocytes in all the biliary atresia livers but present among bile ductule epithelia only on the BA with positive FasL mRNA signals on ductule epithelium. The fibrosis grade was similar between biliary atresia with positive FasL mRNA signals and negative signals. The bile drainage was better in the biliary atresia without positive FasL mRNA signals. CONCLUSIONS: Fas ligand expression on bile ductule epithelia in biliary atresia may be induced to counterattack the infiltrating lymphocytes. Although the factors for post-Kasai bile drainage are multiple, the authors suggest Fas ligand expression on bile ductule epithelia may be a poor prognostic factor by playing a role in the continuous damage and obliteration of intrahepatic bile ducts after Kasai operation.

Base Sequence↗
PubMed2000

Virus infection in patients with histiocytic necrotizing lymphadenitis in Taiwan. Detection of Epstein-Barr virus, type I human T-cell lymphotropic virus, and parvovirus B19.

The relationship of Epstein-Barr virus (EBV), type I human T-cell lymphotropic virus (HTLV-I), and parvovirus B19 to histiocytic necrotizing lymphadenitis was studied prospectively in 10 Taiwanese patients using materials obtained by fine-needle aspiration and lymph node biopsy. The presence of EBV was detected by in situ hybridization for EBV-encoded RNA expression. Immunocytochemistry was used to detect virus-encoded protein for EBV and parvovirus B19. DNA in situ hybridization and polymerase chain reaction were performed to determine the existence of HTLV-I provirus. Expressions of EBV-encoded RNA and Fas ligand were detected in all cases. Expression of EBV-encoded protein was identified in only 1 case. Neither HTLV-I nor parvovirus B19 was detected in any case.

Adolescent↗
PubMed2000

Parvovirus B19 infection in a human immunodeficiency virus-infected patient with anemia.

Anemia is generally attributed to zidovudine therapy in human immunodeficiency virus (HIV)-infected patients, although parvovirus B19 infection has been reported as a rare cause. We report on a 24-year-old homosexual man infected with HIV who presented with anemia. He had received aggressive daily antiretroviral therapy (zidovudine 600 mg, lamivudine 300 mg, and saquinavir 1,800 mg) for 2 years. At the time of admission, his CD4+ count was 10 x 10(6) cells/L. A bone marrow aspirate smear showed a marked decrease in erythropoiesis and immunocytochemical staining for parvovirus B19 was positive. Parvovirus B19 viral DNA was detected in the peripheral blood using a polymerase chain reaction-based assay. Serologic studies were positive for parvovirus B19 immunoglobulin (Ig)M antibodies, but negative for IgG antibodies. The patient was treated with packed red blood cell transfusion. Zidovudine was stopped and replaced with zalcitibine 2.25 mg daily after anemia occurred. He did not receive intravenous Ig therapy because of its cost. After discontinuation of zidovudine for 1 year, anemia persisted and the patient depended on regular blood transfusions to control the anemia. This case emphasizes that, in addition to drug-related causes, parvovirus B19 infection should be included in the differential diagnosis of chronic anemia in HIV-infected individuals.

Adult↗
PubMed2000

Clinical significance of serum soluble interleukin 2 receptor-alpha in esophageal squamous cell carcinoma.

Although the serum level of soluble interleukin-2 receptor alpha (sIL-2Ralpha) has been shown to correlate with progression and prognosis of several cancers, data to support its clinical significance to esophageal squamous cell carcinoma (ESCC) are limited. This study was conducted to assess the prognostic value and source of sIL-2Ralpha in patients with ESCC. From January 1986 to June 1997, 125 patients with histopathologically confirmed ESCC were enrolled for study. Ninety-three patients underwent en bloc esophagectomy, and 32 patients with unresectable tumor underwent palliative surgery. Four (4.3%; 4 of 93) patients died of surgical complications. Serum levels of sIL-2Ralpha were measured by ELISA. Expression of IL-2Ralpha, IL-2Rbeta, and IL-2Rgamma in the pathological section was determined, respectively, by immunohistochemistry (IHC) and in situ hybridization (ISH). Compared with the healthy control group (1020 +/-476 pg/ml, n = 103), ESCC patients tended to have significantly higher serum sIL-2Ralpha concentrations (1424 +/- 798 pg/ml, n = 121). The sIL-2Ralpha level was correlated with age, Tumor-Node-Metastasis classification, tumor stage, reading score of the IHC staining, and survival but not with the pathological grade or lymphovascular invasion. Prognosis was worse for patients with high sIL-2Ralpha levels (> or =1500 pg/ml) than for those with low serum sIL-2Ralpha levels (< 1500 pg/ml; P = 0.0209). It can be used as an independent prognostic factor of ESCC. In the pathological sections, expression of IL-2Ralpha, IL-2Rbeta, and IL-2Rgamma was detected in 17 (18.1%), 83 (89.2%), and 83 (89.2%) cases, respectively, by IHC, and the message of IL-2Ralpha was identified in tumor cells by ISH in 30.1% (28 of 93) of the cases. Serum concentrations of sIL-2Ralpha are frequently elevated in ESCC patients and are correlated with disease progression and survival. These data indicate that, in addition to activated T cells, cancer cells could be an important source of sIL-2Ralpha in ESCC patients.

Aged↗
PubMed1999

Expression of Fas ligand in Langerhans' cell histiocytosis: A case report of a boy with multisystem involvement.

Previous reports of patients with Langerhans' cell histiocytosis have shown characteristics of osteolytic lesion, visceral involvement and organ dysfunction. We report a 2-year-old boy who was diagnosed as Langerhans' cell histiocytosis with a prominent hepatomegaly. X-Radiogram, computed tomography and magnetic resonance imaging revealed the osteolysis of the right iliac bone, the absence of the left eighth rib as well as the right mandible, and an enhancing mass in the left cerebellum. The data of radiography were highly suggestive of Langerhans' cell lineage. The presence of large CD1a-positive mononuclear cells associated with inflammatory cells in peripheral blood smear and bone marrow aspirate further confirmed the diagnosis. In addition, expressions of S100, CD25, CD68, CD80, CD86, and Fas ligand were identified on these cells by immunocytochemical staining. The results indicate that although these cells are activated Langerhans' cells, progression of the disease and the bone destruction could be mediated by the overt FasL expression of the cells.

Antigens, CD↗
PubMed1999

Skip colonic ulceration in typhoid ileo-colitis.

Colonic skip lesions are typically described in Crohn's colitis, but this phenomenon has been recognized in ulcerative colitis (skipped appendiceal involvement), Behcet's colitis, cytomegaloviral colitis, and even in Aeromonas hydrophilia and Histoplasma capsulatum infection. However, skip lesions in typhoid ileo-colitis have not been reported in the English-language literature. We report herein a patient with skip ulcers due to typhoid fever.

Adult↗
PubMed1999

Expression and up-regulation of interleukin-6 in oesophageal carcinoma cells by n-sodium butyrate.

Recently, the serum level of interleukin (IL)-6 has been shown to correlate with disease progression and prognosis of cancer patients. However, the available information about the source and the pathophysiological regulation of IL-6 in cancer cells is limited. Thus, in this study, we tried to identify the source and the clinical roles of serum IL-6 in patients with oesophageal squamous cell carcinoma (ESCC), and then further to characterize the biological regulation of IL-6 in ESCC cell lines. Sera and tissue specimens from 80 consecutive patients with ESCC were collected between 1993 and 1997. Additionally, three ESCC cell lines were used for in vitro study. The concentration of serum IL-6 was measured by enzyme-linked immunosorbent assay (ELISA), and correlated the survival time with measured IL-6 level. Expressions of IL-6, IL-6R alpha (IL-6 receptor alpha) and gp130 in pathological sections and cell lines were characterized by immunological staining. Detection of IL-6 mRNA was determined by in situ hybridization (ISH) and reverse transcription-polymerase chain reaction (RT-PCR). Up-regulation of IL-6 by n-sodium butyrate (n-BT) was studied in ESCC cell lines. The levels of serum IL-6 in patients with ESCC were significantly higher than those in the healthy controls. Serum levels of IL-6 were also shown to correlate with disease progression and survival. However, sCD8 levels and lymphocyte counts in the peripheral blood were not parallel to the changed pattern of serum IL-6. In pathological sections and ESCC cell lines, message of IL-6 was identified by ISH in cancer cells. Expression of IL-6 mRNA was further confirmed with RT-PCR in ESCC cell lines. Although IL-6 was detected in some ESCC cell lines, IL-6 gene expression and protein production could be induced or enhanced by n-BT treatment in all three cell lines. The serum levels of IL-6 are frequently elevated at diagnosis of ESCC, and are associated with poor prognosis. IL-6 that could be produced by cancer cells is up-regulated by n-BT.

Base Sequence↗
PubMed1999

Apoptosis in primary cutaneous amyloidosis.

Amyloid deposits in primary cutaneous amyloidosis (PCA) may be initially derived from cytokeratin. possibly after keratinocyte death. However, the mechanism of keratinocyte death remains obscure. To investigate the potential role of apoptosis in the pathogenesis of PCA, a retrospective study was conducted on the skin tissues from 20 Chinese patients with PCA. We used a terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labelling (TUNEL) method for detecting the apoptotic cells. Immunohistochemical staining was performed to examine the expression of the B-cell leukemia/lymphoma-2 gene (bcl-2) and Fas. Apoptotic cells were shown in 11 of 20 cases (55%) by TUNEL. Histological sections showed that dyskeratotic cells and vacuolar alteration of the basal cells were more commonly observed in the TUNEL-positive group. In all cases of PCA, epidermal expression of bcl-2 was minimal, while expression of Fas was observed on keratinocytes in the basal to granular layers: however, these findings were not different from those in normal skin. Our results suggest that the keratinocyte destruction in PCA may occur as an initial result of apoptosis, which in turn leads to the amyloid formation.

Adult↗