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Biomedical subjects

W C Lin

Publications and source records attributed to W C Lin.

At least 73 records · Page 4Linked to original sources
PubMed1998

Development of Th1 and Th2 populations and the nature of immune responses to hepatitis B virus DNA vaccines can be modulated by codelivery of various cytokine genes.

In this study, we provide direct evidence that the magnitude and nature of the immune response to a DNA vaccine can be differentially regulated by codelivery of various mouse cytokine genes. Mice immunized with a hepatitis B virus (HBV) DNA vaccine and the IL-12 or IFN-gamma gene exhibited a significant enhancement of Th1 cells and increased production of anti-HBV surface IgG2a Ab, as well as a marked inhibition of Th2 cells and decreased production of IgG1 Ab. In contrast, coinjection of the IL-4 gene significantly enhanced the development of specific Th2 cells and increased production of IgG1 Ab, whereas Th1 differentiation and IgG2a production were suppressed. Coinjection of the IL-2 or the granulocyte-macrophage-CSF gene enhanced the development of Th1 cells, while the development of Th2 cells was not affected, and the production of IgG1 and IgG2a Ab were both increased. The CTL activity induced by HBV DNA vaccination was most significantly enhanced by codelivery of the IL-12 or IFN-gamma gene, followed by the IL-2 or granulocyte-macrophage-CSF gene, whereas codelivery of the IL-4 gene suppressed the activity. When challenged with HBV surface Ag (HBsAg)-expressing syngeneic tumors, significant reduction of tumor growth was observed in mice that were coadministered the IL-12 gene but not the IL-4 gene. Taken together, these results demonstrate that application of a cytokine gene in a DNA vaccine formulation can influence the differentiation of Th cells as well as the nature of an immune response and may thus provide a strategy to improve its prophylactic and therapeutic efficacy.

Adjuvants, Immunologic↗
PubMed1998

Tyrosine kinase expression profiles of chicken erythro-progenitor cells and oncogene-transformed erythroblasts.

Tyrosine kinases are implicated in the growth and differentiation of erythroid cells. Aberrant expression and structural alterations of certain tyrosine kinases, such as erbB and sea, are known to trigger erythroleukemia development. To facilitate our understanding of the signal transduction pathways involved in erythroid differentiation and leukemic transformation, we have applied a recently developed tyrosine kinase profile technique to identify the tyrosine kinases and some novel serine/threonine kinases expressed in normal chicken erythroid progenitor cells that respond to TGFalpha (TGFalpha-EB), and erythroblasts transformed by viruses encoding v-erbB (v-erbB-EB) and v-sea (v-sea-EB). Our results reveal that the non-receptor tyrosine kinases, Abl, Fyn, Lyn, Btk and Csk, are expressed in all three cell types. The expression level of Btk, a tyrosine kinase implicated in Bruton's syndrome, is exceptionally high in the erythroblastoid cell line 6C2, transformed by the v-erbB carrying avian erythroblastosis virus, AEV-ES4. We have also uncovered a new STE-20-related serine/threonine kinase, KFC, which is abundantly expressed in both the TGFalpha-stimulated erythroid progenitor cells and v-sea-transformed erythroblasts. Based on sequence homology of the kinase domain, KFC appears to be the first member of a new subfamily of STE-20-like kinases.

Amino Acid Sequence↗
PubMed1998

Protein-tyrosine kinase and protein-serine/threonine kinase expression in human gastric cancer cell lines.

Protein kinases play key roles in cellular functions. They are involved in many cellular functions including; signal transduction, cell cycle regulation, cell division, and cell differentiation. Alterations of protein kinase by gene amplification, mutation or viral factors often induce tumor formation and tumor progression toward malignancy. The identification and cloning of kinase genes can provide a better understanding of the mechanisms of tumorigenesis as well as diagnostic tools for tumor staging. In this study, we have used degenerated polymerase-chain-reaction primers according to the consensus catalytic domain motifs to amplify protein kinase genes (protein-tyrosine kinase, PTK, and protein-serine/threonine kinase, PSK) from human stomach cancer cells. Following amplification, the protein kinase molecules expressed in the gastric cancer cells were cloned into plasmid vectors for cloning and sequencing. Sequence analysis of polymerase-chain-reaction products resulted in the identification of 25 protein kinases, including two novel ones. Expression of several relevant PTK/PSK genes in gastric cancer cells and tissues was further substantiated by RT-PCR using gene-specific primers. The identification of protein kinases expressed or activated in the gastric cancer cells provide the framework to understand the oncogenic process of stomach cancer.

Amino Acid Sequence↗
PubMed1998

Isolation and identification of novel protein kinase genes from the round-spotted pufferfish (Tetraodon fluviatilis) genomic DNA.

The round-spotted pufferfish Tetraodon fluviatilis has a genome size of 380 Mb which is slightly smaller than that of another pufferfish, Fugu rubripes rubripes (Fugu). Due to their compact genome and small introns, both pufferfishes have been proposed as model organisms for genome studies. In this study, we have used genomic DNA as template to perform PCR to screen for protein kinase (pk) genes. Forty-one T. fluviatilis pk genes encoding 7 receptor tyrosine kinases, 14 nonreceptor tyrosine kinases, 16 serine/threonine kinases, 1 dual kinase and 3 novel kinases have been identified. The success of this approach depends on the size and location of the introns. Most of the identified pk gene fragments contain introns, ranging from 71 to 300 bp, with an average of 120 bp. It is noteworthy that the intron/exon boundaries of certain genes which belong to the same family are identical. We also analyzed by specific RT-PCR primers the expression profile of those 3 novel genes as well as some selected pk genes in a variety of tissues. We found that erbB3, pku a, mrk, CaMK I, CaMKIIgamma, and two novel kinase genes (133 and 3-26) are expressed in all tissues examined. However, the novel clone 146 is strongly expressed in the brain and weakly in the intestine, kidney and heart.

Amino Acid Sequence↗
PubMed1998

Tumor progression, micrometastasis, and genetic instability tracked with histochemical marker genes.

Mouse fibrosarcoma (3T3 cells transfected with different oncogenes), human neuroblastoma, or human prostate carcinoma cells have been genetically-tagged with different histochemical marker genes (E. coli lacZ, placental alkaline phosphatase, or Drosophila alcohol dehydrogenase). Injection into athymic nude mice permits their tracking at all stages of primary tumor formation and micrometastasis to various organs at the single-cell level. Two different tumor classes, tagged with different marker genes, can be tracked together. Primary tumors display regional dominance of one tumor class with exclusion of other classes. During micrometastasis, tumor cells are detected binding to the endothelium of lung blood vessels, followed by establishment of multiple-cell micrometastases. Micrometastases in some organs are transient while in other organs there is differential expansion into overt metastases. Tagged tumors also reveal the timing of angiogenesis of developing primary tumors and overt metastases. In all three tumor systems, there are three classes of genetic stability of marker gene expression in clonal populations-high stability, intermediate stability, and high instability. Instability in marker gene expression in one tagged prostate carcinoma system does not depend on a hypermethylation mechanism, suggesting a genetic basis for loss of activity. Use of histochemical marker genes, combined with laser-capture microdissection and various PCR methods, can now be used to evaluate gene activities in single or multiple tumor cells in virtually any organ and primary tumor of the animal model system.

Animals↗
PubMed1998

Phase II trial of intrapleural paclitaxel injection for non-small-cell lung cancer patients with malignant pleural effusions.

A phase II clinical trial of intrapleural paclitaxel injection for malignant effusions of non-small-cell lung cancer (NSCLC) was conducted in order to evaluate the efficacy and toxicity profile of paclitaxel pleurodesis in patients with malignant effusions. From February to May of 1996, 15 NSCLC patients with malignant pleural effusions were enrolled on study. After adequate drainage and assurance of lung re-expansion, paclitaxel 125 mg m-2 diluted in normal saline was infused through a preinserted pig-tail catheter which was removed 2 h later. Chest radiography and sonography were scheduled 4 days later; depending on whether there remained a significant amount of pleural effusion, further drainage by needle thoracentesis or by a pig-tail catheter was performed. All patients were assessable for toxicity. Ipsilateral chest and/or shoulder pain, fever, facial flushing and nausea were the most frequent side-effects. Grade 4 neutropenia, grade 3 anaemia, and grade 3 renal impairment occurred in one patient each. Fourteen patients were evaluable for response at the end of the fourth week. Overall response rate of pleural effusion in evaluable patients was 92.9%, with a complete response rate of 28.6%. There was one out of 14 evaluable patients whose measurable tumour lesion decreased by more than 50% (partial response). No disease progression was noted among evaluable patients at the end of the fourth week. It is concluded that paclitaxel is a useful agent for the treatment of malignant pleural effusions. Because of its relatively low systemic toxicity, intrapleural paclitaxel injection in combination with systemic chemotherapy or radiotherapy can be considered in treating NSCLC patients with malignant pleural effusions.

Aged↗
PubMed1998

Prevention of ethanol-induced gastric lesions in rats by wu-bei-san.

The effects of Wu-Bei-San (WBS) and its components Wu-Tsi-Ku (WTK) and Bei-Mu (BM) on gastric lesions induced by necrotizing agents were investigated in rats. Oral administration of WBS or WTK, but not BM, dose-dependently prevented gastric lesions induced by ethanol. Moreover, the gastric protective action of WTK was potentiated by simultaneous administration of BM under the same experimental conditions. Pretreatment with indomethacin, which is a prostaglandin synthesis inhibitor and idoacetamide, which is a sulfhydryl blocker did not influence the inhibited ethanol lesion of WBS. Gastric lesions induced by acidified aspirin were prevented by both WBS and calcium carbonate, which is a major constituents of WTK. However, pretreatment with calcium carbonate did not affect the gastric lesions induced by ethanol. These results indicate protective action of WBS on the gastric mucosa through both acid neutralization and cytoprotection, although more work is needed to clarify the role of WBS in cytoprotection.

Animals↗
PubMed1998

Effect of pretreatment of rats with an urinary preparation on liver injuries induced by carbon tetrachloride and alpha-naphthylisothiocyanate.

The effect of oral administration of a preparation of human urine (PHU) on the progression of acute liver injury was examined in rats intoxicated with carbon tetrachloride (CCl4) and alpha-naphthylisothiocyanate (ANIT) PHU protected the liver from CCl4-induced injury as judged by morphological and biochemical observations. In contrast, PHU aggravated ANIT-induced injury as judged also by morphological and biochemical observation. PHU prevented the increase in hepatic glutathione (GSH) and lipid peroxidation induced by CCl4. But PHU enhanced the increase in hepatic GSH caused by ANIT. These results indicate that the effect of PHU on hepatic GSH concentrations is through an indirect pathway. Clinical application of PHU on hepatitis should be explored further.

1-Naphthylisothiocyanate↗
PubMed1998

The mechanism of successful colposuspension in genuine stress incontinence.

BACKGROUND: Colposuspension (Burch procedure) is one of the most effective surgical procedures for the cure of genuine stress incontinence in women. The aim of the current study was to understand the mechanism of successful colposuspension for treatment of this condition. METHODS: Thirty-five patients with primary genuine stress incontinence underwent colposuspension. Preoperative investigation included detailed history taking, urinalysis, pelvic floor relaxation assessments, one-hour pad test, Q-tip test, urodynamic study and perineal ultrasound urethrocystography. Follow-up results were estimated after one year. RESULTS: Twenty-five (71.4%) patients were completely cured; four (11.4%) patients showed significant improvement and six (17.1%) had recurrence of incontinence. The overall success rate was 82.9%. The complication rate was 20%. Urodynamic data revealed a significant increase in the maximal stress urethral closure pressure and proximal urethral transmission ratios. Perineal ultrasound urethrocystography and Q-tip test revealed a significant anatomic correction in bladder neck descent. CONCLUSIONS: This study confirmed that surgical cure of urinary incontinence can be achieved by restoration of the vesical neck from a dependent position in the pelvis to a position high behind the symphysis pubis, with subsequent improved pressure transmission ratios.

Adult↗
PubMed1998

Primary retroperitoneal liposarcoma mimicking ovarian cancer: a case report.

Primary retroperitoneal liposarcoma is a rare malignancy comprising about only 0.1% of all cancers. It produces nonspecific symptoms and is often extensive when diagnosed. In this report, we present a case of a 68-year-old female patient who had a 29-kg retroperitoneal liposarcoma. Her early symptoms--including vague digestive disturbances, increasing abdominal girth and an abdominal mass, and clinical examinations such as sonography and computed tomography scan led to a preoperative diagnosis of ovarian cancer, until surgical and pathologic confirmation. Gross, radical resection of the tumor was successfully performed, and provided the most effective primary therapeutic approach. Histopathology revealed a mixed-type liposarcoma, with metastasis to the appendix. A poor prognosis was expected. Postoperative periodic follow-up was started to monitor for early detection of recurrence.

Aged↗
PubMed1998

Laparoscopic radical hysterectomy with low paraaortic, subaortic and pelvic lymphadenectomy. Results of short-term follow-up.

OBJECTIVE: To describe a detailed operative procedure for type III laparoscopic radical hysterectomy with bilateral low paraaortic, subaortic and pelvic lymphadenectomy. STUDY DESIGN: Between January 1992 and December 1995, eight patients with cervical carcinoma IA2 or IB1 underwent laparoscopic radical hysterectomy at China Medical College Hospital, Taichung, Taiwan, R.O.C. The procedure of laparoscopic radical hysterectomy was separated into eight segmental steps. RESULTS: No major complications, including ureteral injury and lymphocyst formation, were noted in any case. Mean hospitalization was 6.5 days. The follow-up period ranged from 16 to 62 months. Only one case recurred, in the lung. CONCLUSION: Laparoscopic radical hysterectomy is a safe procedure. A complete pelvic and paraaortic lymphadenectomy and type III radical hysterectomy can be performed laparoscopically. This approach allows shorter hospitalization and carries less morbidity than the open type. Short-term follow-up (1.3-5.1 years) indicated a favorable prognosis.

Adult↗
PubMed1998

Ifosfamide-based chemotherapy for previously treated lung cancer patients.

BACKGROUND: Ifosfamide-based chemotherapy has already been the basis of three separate clinical trials. In this study, ifosfamide was administered to lung cancer patients who had failed to respond to previous chemotherapy, to assess its response rate and toxicity. METHODS: From January 1993 to December 1996, 21 patients were treated, including eight patients with small cell lung cancer (SCLC) and 13 with non-small cell lung cancer (NSCLC). Patients who had histocytologically confirmed lung cancer, were previously treated with chemotherapy, had a measurable lesion(s), were younger than 75 years of age, had an Eastern Cooperative Oncology Group performance status of 0-3 and adequate marrow, renal and liver function were eligible for inclusion in this study. For SCLC patients, ifosfamide 2.4 g/m2 intravenous (i.v.) infusion was given over 30 minutes on days 1-3 every four weeks. For NSCLC two regimens were used: IFL (ifosfamide 2 g/m2, 5-fluorouracil (FU) 600 mg/m2 and leucovorin 50 mg/m2 i.v. infusion on days 1-3 every four weeks) and LIFE (leucovorin 50 mg/m2, ifosfamide 1 g/m2, 5-FU 400 mg/m2 and epirubicin 12 mg/m2 i.v. infusion on days 1-3 every four weeks). For NSCLC patients, IFL was used for the first two years of treatment and LIFE was used in the last two treatment years. All patients were evaluated for treatment response and toxicity. RESULTS: The major toxic effect, myelosuppression (grade 3 or 4 leukopenia), occurred in 62.5% of SCLC patients and 23.1% of NSCLC patients during treatment, and in 62.5% and 10% of SCLC and NSCLC patients, respectively, throughout the course. Only one SCLC and one NSCLC patient experienced febrile neutropenia. One toxic death, attributed to febrile neutropenia, was documented in a patient with SCLC. Alopecia was ubiquitous. Other toxicities were uncommon and mild. The overall response rate was 50% in SCLC and 7.7% in NSCLC. The median time to disease progression was 61 days in SCLC and 47 days in NSCLC. Median survival was 172 days in SCLC and 173 days in NSCLC. CONCLUSIONS: The study results suggest that ifosfamide chemotherapy is active with an acceptable toxicity profile in previously treated SCLC patients. However, it lacks efficacy in NSCLC patients who have been previously treated.

Adult↗
PubMed1998

Systemic Penicillium marneffei infection in a child with common variable immunodeficiency.

Penicillium marneffei is rarely pathogenic in humans. Most previously reported cases of P. marneffei infection were from Southeast Asia where patients were usually in an immunocompromised state due to human immunodeficiency virus (HIV) infection. The majority of the patients reported in Western countries were immunocompromised by malignancy, especially Hodgkin's lymphoma. In Taiwan, the first case of P. marneffei infection was reported in 1994 and involved an adult with HIV infection. We report a case of systemic P. marneffei infection in a child with common variable immunodeficiency (CVID). The patient, a 4-year, 5-month-old boy, had a 1-year history of oligoarthritis resembling juvenile rheumatoid arthritis (JRA). He developed a low grade fever (38 degrees C) and hepatosplenomegaly 1 month before admission to the hospital. Although cultures of synovial fluid obtained at the time of onset of oligoarthritis did not grow any organisms, cultures of blood, bone marrow, synovial fluid, and lymph node biopsy samples taken during this admission were positive for P. marneffei. Further immunologic studies revealed a profile characteristic of CVID. The fungal infection was finally eradicated by combined therapy with amphotericin B, fluconazole, itraconazole, and regular immunoglobulin replacement. This case reminds us that JRA or JRA-like arthritis should be differentiated from septic arthritis caused by rare pathogens in immunocompromised patients.

Arthritis, Infectious↗
PubMed1997

Migration behavior and selectivity of sulfonamides in capillary electrophoresis.

The migration behavior and selectivity of thirteen sulfonamides in capillary electrophoresis (CE), with emphasis on micellar electrokinetic chromatography (MEKC) were systematically investigated using a phosphate-borate buffer electrolyte, with sodium dodecyl sulfate (SDS) as an anionic surfactant in MEKC. The optimization strategies for the separation of sulfonamides in capillary zone electrophoresis (CZE) and in MEKC are described. The migration behavior and selectivity of sulfonamides in CZE are mainly manipulated by the pH of the buffer. The migration order of sulfonamides depends on the ratios of charge to mass (q/M2/3) and is primarily determined by their pKa values. Thus precise optimization of buffer pH is crucial to further improve the separation of some closely migrating sulfonamides. On the other hand, buffer pH and micelle concentration greatly affect the migration and selectivity of sulfonamides in MEKC. The migration order of sulfonamides is mainly determined by their pKa values and the magnitude of the binding constants of solutes-to-micelles. The influences of buffer pH and micelle concentration correlate with each other. The magnitude of the binding constants correlates with the differences between the electrophoretic mobility of sulfonamides measured at a pH below pKa-2 in CZE and that in MEKC. In this work, acid dissociation constants of these sulfonamides and binding constants of sulfonamides to SDS micelles in a phosphate-borate buffer are reported.

Anti-Infective Agents↗
PubMed1997

Expression of a gene encoding a 16.9-kDa heat-shock protein, Oshsp16.9, in Escherichia coli enhances thermotolerance.

A gene encoding the rice 16.9-kDa class I low-molecular-mass (LMM) heat-shock protein (HSP), Oshsp16.9, was introduced into Escherichia coli using the pGEX-2T expression vector to analyze the possible function of this LMM HSP under heat stress. It is known that E. coli does not normally produce class I LMM HSPs. We compared the survivability of E. coli XL1-Blue cells transformed with a recombinant plasmid containing a glutathione S-transferase (GST)-Oshsp16.9 fusion protein (pGST-FL cells) with the control E. coli cells transformed with the pGEX-2T vector (pGST cells) under heat-shock (HS) after isopropyl beta-D-thiogalactopyranoside induction. The pGST-FL cells demonstrated thermotolerance at 47.5 degrees C, a treatment that was lethal to the pGST cells. When the cell lysates from these two E. coli transformants were heated at 55 degrees C, the amount of protein denatured in the pGST-FL cells was 50% less than that of the pGST cells. Similar results as pGST-FL cells were obtained in pGST-N78 cells (cells produced a fusion protein with only the N-terminal 78 aa in the Oshsp16.9 portion) but not in pGST-C108 cells (cells produced a fusion protein with C-terminal 108 aa in the Oshsp16.9 portion). The acquired thermotolerant pGST-FL cells synthesized three types of HSPs, including the 76-, 73-, and 64-kDa proteins according to their abundance at a lethal temperature of 47.5 degrees C. This finding indicates that a plant class I LMM HSP, when effectively expressed in transformed prokaryotic cells that do not normally synthesize this class of LMM HSPs, may directly or indirectly increase thermotolerance.

Cloning, Molecular↗
PubMed1997

Microsatellite instability in sporadic-colon-cancer patients with and without liver metastases.

Microsatellite instability (MSI) is intrinsic to most colorectal carcinomas (CRC) from patients with hereditary nonpolyposis colorectal cancer (HNPCC), reflecting germline mutations in the mismatch-repair (MMR) genes. Its occurrence and chronological sequence of development in sporadic CRC appears less well defined. To explore the time sequence in acquisition of MSI, and the role it plays during tumor progression in sporadic CRC, we compared the incidence of MSI in tissue samples from 40 Dukes'-B and 30 Dukes'-D CRC patients with liver metastases, at 4 different microsatellite loci, representing sites on the APC, DCC and p53 genes respectively as well as the D2S123 site. Among the 30 patients with hepatic metastases, MSI was found in 9 (30%) of the primary, and 13 (43.3%) of the metastatic tumors. In comparison, among the 40 Dukes'-B CRC, MSI was found in only 8 cases (20%). CRC with MSI were more frequently located in the right colon, less frequently on the left side, and seldom in the rectum. Tumor ploidy analysis shows that 46.2% of Dukes'-D primary tumors with MSI are diploid (chi2 = 4.46, p = 0.035). With a mean follow-up time of 4.2 years for the Dukes'-B CRC, there were no recurrences in the 8 patients with MSI, whilst 6 (18.8%) relapses occurred amongst the 32 patients without MSI, average time to recurrence being 15 months. In Dukes'-D CRC, mean survival time for patients with MSI was 37 months (95% CI, 24 to 51 months), for those without MSI 26 months (95% CI, 18 to 35 months), although this was not statistically significant. Our data suggest that tumor progression may involve increased genetic instability.

Aged↗
PubMed1997

Factors affecting the decision of nursing students in Taiwan to be vaccinated against hepatitis B infection.

Compliance with Hepatitis B vaccination for nurses has been reported to be low in Taiwan. Therefore, a study of nursing students' view was conducted in Taiwan to discover possible reasons. As complex decision-making was involved in taking the vaccine, a four-level utility decision model underpinned by the Multi-Attribute Utility theory was proposed to ascertain the relative contribution of the specific components of attitude and beliefs to the final decision and experience of being vaccinated against Hepatitis B infection. Results indicated that the 'personal value of Hepatitis B vaccination', in particular for 'concern about the efficacy of the Hepatitis B vaccine', 'fear of pain from repeated injections', 'time' and 'money', were the main determinants in relation to the uptake of the Hepatitis B vaccination. Such results were consistent with earlier findings based on the Health Belief Model. It appears that the greater the experience gained in nursing care the lower the rate of vaccination; the important items under the concept of 'Personal value of Hepatitis B vaccination' varied by 'experience in nursing care'. The overall predictive validity was 67%, based on the utility decision model. When stratified by 'experience in nursing care', the prediction improved, ranging from 89% to 100%. Based on these findings, a specific intervention programme should be provided to change behaviour and improve the vaccination rate.

Analysis of Variance↗