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Biomedical subjects

C J Wu

Publications and source records attributed to C J Wu.

At least 91 records · Page 5Linked to original sources
PubMed1995

Functional characterization of the promoter region of the platelet-activating factor receptor gene. Identification of an initiator element essential for gene expression in myeloid cells.

To understand the molecular mechanisms that direct the expression of the gene encoding the platelet-activating factor (PAF) receptor, the 5'-flanking region of the human PAF receptor gene was cloned, and its promoter activity in myeloid cell lines was characterized. By the 5'-rapid amplification of cDNA ends method and primer extension, the transcription initiation site was mapped to an adenosine residue 137 bases upstream of the ATG translation initiation codon. The promoter region lacks a typical TATA or CCAAT box. However, the sequence encompassing the transcription initiation site shows high homology to the initiator (Inr) sequence. Transfection of promonocytic U937 cells with recombinant plasmids containing a series of truncated segments of the 5'-flanking region linked to the luciferase reporter gene revealed that the sequence from nucleotides -44 to +27 relative to the transcription initiation site was sufficient to promote a high level of gene expression. The promoter activity was much lower in nonexpressing HeLa cells and promyelocytic HL-60 cells, which express relatively low levels of the PAF receptor. Gel mobility shift analysis demonstrated the binding of nuclear factors extracted from myelocytic cells to the -16/+18 sequence containing the Inr element. No binding activity was detected using the nuclear extracts from the nonmyelocytic HeLa cells. The DNA-protein complexes were sequence-specific since the binding was not significantly affected by the mutated Inr sequences or the Inr sequence of the terminal deoxynucleotidyltransferase gene. Furthermore, point mutations in the Inr element significantly reduced promoter activity in both U937 and THP-1 cell lines. When Me2SO or retinoic acid was used to induce granulocytic differentiation of HL-60 cells, a distinct Inr-protein complex was induced concurrently, but the complex was not observed in 12-O-tetradecanoylphorbol-13-acetate-induced monocytic differentiated HL-60 cells or Me2SO-induced differentiated U937 cells, indicating that the inducible Inr binding activity is granulocyte-specific. These results suggest that distinct nuclear factors interact with the unique Inr element and play a role in the transcriptional regulation of the PAF receptor in various myeloid cells.

Base Sequence↗
PubMed1995

Relationship of multidrug resistance to rhodamine-123 selectivity between carcinoma and normal epithelial cells: taxol and vinblastine modulate drug efflux.

Preferential retention and cytotoxicity of Rhodamine-123 (Rho-123) was originally reported in a number of carcinoma cell types isolated from a variety of tissues as compared to normal epithelial cells from a limited number of other tissues. In the present study, we have examined Rho-123 selectivity in normal and tumor cell lines isolated from the same tissue source, i.e., human breast. We found that: (a) in matched pairs of normal and carcinoma breast cells, Rho-123 displays no preferential retention in either cell type; (b) there is no preferential toxicity in carcinoma as compared to normal breast cells; in fact, one of the carcinoma cell lines (MDA-MB231) shows moderate resistance to this dye; (c) all of the human breast cell lines do not express P-glycoprotein-mediated multidrug resistance; (d) the normal monkey kidney epithelial cell line CV-1, which was originally used as a model to demonstrate the relative resistance of normal epithelial cells to this drug, is found to express high levels of the mdr-1 gene, is resistant to other multidrug-resistant drugs (taxol and vinblastine), and its resistance to Rho-123 as well as decreased Rho-123 retention can be reversed by verapamil; and (e) taxol and vinblastine are found to block increased Rho-123 efflux in CV-1 cells. Thus, overall the data suggest that preferential retention and cytotoxicity of Rho-123 in carcinoma versus normal epithelial cells is related to the differential expression of the mdr-1 gene.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

Study on in vivo release of levonorgestrel-containing silicon capsule.

The in vivo release rate of levonorgestrel-containing silicon capsule (in vitro releasing rate: 6 micrograms/d) placed in rabbits was determined. The results showed that the average release per year was 8.32 micrograms with r being 0.96000. The release pattern of the levonorgestrel-containing silicon capsule system was proved to be zero-order release. Our study provided some experimental data for clinical use of the system for birth control.

Animals↗
PubMed1995

Digital radiographic images will benefit endodontic services.

Future assurances for endodontic services and assessments of traumatized teeth will depend in part on significant improvements to the quality of dental radiographs. Whereas digital images offer many potential sensor, display and archival advantages over film-based radiographs, the marginal image improvements from intraoral sensors primarily benefit patient education. Precisely digitized conventional radiographs are more likely to yield quantum image resolution improvements, although neither dentists nor patients will benefit until cost-effective digitizing systems have been developed for the dental office.

Alveolar Bone Loss↗
PubMed1995

Villous adenoma of ampulla of Vater: a case report.

A 56-year-old female patient presented with pain and tenderness over the epigastric region. Endoscopy showed a polypoid mass at the ampulla of Vater. Endoscopic biopsy showed villous adenoma with moderate cellular atypia. Wide excision of the tumor was performed. After resection, histological examination confirmed the tumor to be a villous adenoma of ampulla of Vater. This is a rare neoplasm with an incidence of 0.04-0.12% in postmortem series. A few cases have been reported in the literature, but only two documented in the Chinese literature to date. Wide excision has had good results and should be regarded as the treatment of choice for benign lesions.

Adenoma, Villous↗
PubMed1995

Atrial septal motion in effusive--constrictive pericarditis: transesophageal echocardiographic study and hemodynamic correlation.

Transesophageal echocardiography was performed in 7 patients with effusive-constrictive pericarditis to analyze atrial septal motion(ASM). In 3 patients, the ASM was found to be normal with atrial septum (AS) moving toward the right atrium from ventricular mid-systole to early-diastole and toward the left atrium from mid-diastole to early-systole. Respiration had little effect on the ASM. In 2 patients, a brisk inversion of ASM toward the left atrium at ventricular early-to-mid systole was noted during inspiration. In the other 2 patients, a sustained ASM toward the left atrium during ventricular systole was found. In 4 of these 7 patients, hemodynamic studies were performed simultaneously with the transesophageal echocardiography. The ASM reflected the pressure gradient between the left atrium (as measured by pulmonary arterial wedge pressure) and the right atrium. The augmented ASM toward the left atrium occurred as left atrial pressure decreased markedly during inspiration. In conclusion, the ASM in patients with effusive-constrictive pericarditis showed 3 patterns: normal, sustained systolic motion toward the left atrium and a brisk systolic displacement toward the left atrium during inspiration. The ASM reflects changes in the interatrial pressure gradient.

Adult↗
PubMed1994

Clinical evaluation of a renal mass diagnostic expert system.

In this paper, we describe our clinical evaluation of the diagnostic accuracy of the renal mass diagnostic system (RMDS) and of seven physicians. To investigate the value of intravenous urography (IVU) and/or retrograde urography (RU) in diagnosing renal parenchymal tumors and tumors of the renal pelvis, RMDS and the seven physicians were tested with and without the information regarding IVU/RU at two different times. From this study we believe that RMDS can help residents in making more accurate presurgical renal mass diagnosis, and may eliminate the need for IVU/RU in the diagnosing process for a specific group of patients.

Adolescent↗
PubMed1994

Cytokine gene expression in human cardiac allograft recipients.

The long-term success of heart transplantation for end-stage heart disease has been hindered by the problems associated with acute and chronic graft rejection, opportunistic infections and potentially fatal complications of intensive immunosuppression. A more complete understanding of the biology of transplant rejection should provide the basis for the development of improved methods for controlling and monitoring rejection. Cytokines, the soluble factors which regulate the immune response, are central to the rejection process. The objective of this study was to analyse cytokine mRNA transcripts in 99 biopsy samples and 89 blood samples from 65 and 35 Stanford Medical Center cardiac transplant recipients, respectively, gathered between January 1990 and January 1992. Following RNA extraction and conversion to cDNA, samples were amplified with cytokine-specific primers for interleukins (IL) 1 to 8, TNF-beta (tumour necrosis factor-beta) and IFN-gamma (interferon-gamma) and were analysed by gel electrophoresis and Southern blot hybridization. Our results demonstrate that despite chronic immunosuppressive therapy, the peripheral blood of transplant recipients expressed a higher combined percentage of different cytokine transcripts than did peripheral blood obtained from normal volunteers. In transplant patients, detection of cytokine transcripts for IL-1 alpha, IL-1 beta and IL-2 increased with time after transplantation. Intragraft IL-7 gene expression was significantly increased in biopsies diagnosed with mild (grade 1) rejection when compared to those with no evidence of rejection or with moderate to severe rejection. Implications of these results in light of possible mechanisms of rejection and of new approaches to immunotherapy are discussed.

Blotting, Southern↗
PubMed1994

When will excellent radiographic images be available to the general dental office?

Dental radiography is a highly regarded diagnostic practice. More than 25% of all radiographs are taken for dental purposes, so their improvement will benefit many patients. Although recent advances in materials and processing have contributed to incremental improvements in film-based diagnoses, computer-based enhancement of digitized conventional radiographic images is likely to yield more significant benefits. However, until cost-effective digitizing systems have been developed for the general dental office, the benefits derived from precise radiographic diagnoses and associated improvements in the standards of care will continue to elude both dentist and public.

Humans↗
PubMed1994

Two multidrug-resistant Friend leukemic cell lines selected with different drugs exhibit overproduction of different P-glycoproteins.

Two Friend leukemic multidrug-resistance (MDR) cell lines were established by exposure to stepwise increased concentrations of rhodamine-123 (RHO) (cell line RR-30) or Adriamycin (ADR) (cell line ARN-15). RR-30 displays preferential resistance to RHO, whereas ARN-15 is more resistant to ADR. The levels of resistance to other MDR drugs and reversibility by verapamil between these two MDR cell lines were somewhat different. Southern blot, RNase protection, and Western blot analysis using gene-specific probes demonstrated that RR-30 and ARN-15 cells preferentially amplified the mdr1 and mdr3 genes, respectively, leading to overexpression of the corresponding P-glycoproteins (p-gp). Our results suggest that members of the mdr gene family can be amplified independently by using different selecting agents, which could be responsible for the differences in the sensitivities to these selecting agents as well as to these MDR drugs.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1993

Using ILIAD system shell to create an expert system for differential diagnosis of renal masses.

Differential diagnosis of renal masses is an important and difficult process. A renal mass diagnostic system (RMDS) developed by using the ILIAD expert system shell has been created for diagnostic consultations and patient simulations. Seventy-two cases of renal mass have been tested on this system and the diagnostic accuracy was compared to that of residents. The overall diagnostic accuracy (75%) for renal masses is significantly better than second-year urological residents (60%) and not worse than urological chief residents (71%). The expert system also displays the cost of the diagnostic procedures so that the user can choose the most cost-effective diagnostic process. We conclude that this powerful renal mass diagnosis system developed by using ILIAD system shell can be used as a teaching, self-training and clinical tool for urological residents.

Artificial Intelligence↗
PubMed1993

Cytokine gene expression in human lung transplant recipients.

The polymerase chain reaction was used to evaluate cytokine gene expression in bronchoalveolar lavage (BAL) cells and peripheral blood leukocytes in 31 human lung transplant recipients. All patients were maintained on a triple immunosuppression regimen consisting of CsA, AZA, and prednisone. Posttransplant survival ranged from 0.5 to 100.5 months (mean = 16.3 months). Cytokines IL-1 alpha, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, TNF-beta, and IFN-gamma were studied. In BAL, transcripts for IL-1 alpha, IL-7, IL-8, and TNF-beta were found in over 60% of samples and those for IL-5, IL-6, and IFN-gamma in 40-50%, while IL-2 and IL-4 mRNA were rarely found (< 20%). Considerable variation in the frequency of cytokine gene expression between BAL and peripheral blood was observed. When analyzed for the presence of acute pulmonary allograft rejection (without infection), transcripts for IL-4 and IL-6 in BAL demonstrated the greatest increase in frequency compared with nil rejection (P = 0.07 and P = 0.17, respectively). Pulmonary infection (without rejection) was associated with a modest increase in the expression of genes for IL-1 alpha and IFN-gamma (> 10%). Transcripts for IL-4 were not found in association with pulmonary infection, suggesting that this cytokine may be useful as a discriminatory rejection marker.

Adolescent↗
PubMed1993

Long-term outcome of acupuncture in women with frequency, urgency and dysuria.

Urodynamic measurements including cystometry, anal sphincter electromyography, urethral pressure profilometry and uroflowmetry were carried out on 21 female patients before acupuncture and at 1 and 3 years during follow-up. Follow-up ranged from 60 to 72 months (average 66.2 months). There was no significant difference in all urodynamic measurements before acupuncture and at the 1 year or 3 years follow-up. During follow-up, acupuncture at the Sp-6 point was performed in patients who had recurrence of symptoms of frequency, urgency and dysuria. The number of acupuncture treatments ranged from 2 to 8 times, with an average number of 4.8 times. A decrease of acupuncture treatments after 30 months was noted on 8 patients, but it was not statistically significant. We concluded that the long-term outcome of acupuncture at the Sp-6 point for women with frequency, urgency and dysuria was positive, but that the effect was temporary and repeated acupuncture was necessary to maintain beneficial effects.

Acupuncture Points↗
PubMed1992

Xanthogranulomatous pyelonephritis: experience in 36 cases.

A retrospective study of 36 patients with xanthogranulomatous pyelonephritis who underwent nephrectomy at our hospital was performed. The disease occurred most frequently in middle-aged women with a history of recurrent urinary tract disorder. There were 2 cases of focal xanthogranulomatous pyelonephritis, 2 associated with emphysematous pyelonephritis, 2 that manifested as fistula formation between the colon or skin, and 1 with deep sinus formation into the hip joint that presented as septic arthritis. Flank pain and fever were the most frequent complaints. Escherichia coli (67%) and Proteus mirabilis (26%) were the most common organisms isolated from the voided urine, kidney and blood stream. Cephalothin plus gentamicin or tobramycin were the drugs of choice before surgical intervention.

Adult↗
PubMed1992

Cytokine gene expression in rejecting cardiac allografts.

Heart transplantation is now a viable therapeutic option for patients with certain end-stage cardiac diseases. However, episodes of rejection, opportunistic infection, and life-threatening side effects of generalized immunosuppression remain very real problems for these patients. A better understanding of the molecular mechanisms underlying rejection may provide the basis for the development of more specific, less toxic immunosuppressive therapies. While cytokines have long been implicated in the pathogenesis of rejection, the precise role of each cytokine in this process has yet to be defined. We report here the application of the polymerase chain reaction (PCR) to the detection of cytokine mRNA in biopsies obtained from heterotopic abdominal cardiac allografts in cynomolgus monkeys. With the exception of IL-6 and IL-8, cytokine transcripts were undetectable in samples obtained from the donor heart pretransplant. In contrast, IFN-gamma transcripts were detected in all transplants two days after surgery before evidence of rejection was demonstrable by histopathologic analysis. IL-1 beta, IL-2, and IL-6 transcripts were detected when minimal rejection was noted. At later times, IL-1 alpha, IL-1 beta, IL-2, IL-6, IL-8, TNF-beta, and IFN-gamma transcripts were detectable. Further characterization of the spectrum of cytokines expressed at various stages of rejection may lead to insights into the biology of transplant rejection and to the development of more specific and potent reagents to diagnose and/or treat rejection.

Animals↗
PubMed1992

Purification and properties of chitinase from cabbage.

Chitinase has been purified from the extract of cabbage through successive steps of ammonium sulfate fractionation, chromatofocusing and Sephadex G-75 gel filtration. By these steps, the purity of the enzyme increased by 93.3 fold and the recovery of the enzyme activity was 20%. The purified enzyme had an optimal pH of 5.0, an optimal temperature between 40 to 50 degrees C and a Km of 76 microM for hydrolysis of ethylene glycol chitin. The molecular weight of the enzyme determined from filtration through Sephadex G-75 was 30,000 daltons. Heavy metal ions, Hg2+ (0.5 mM) and Ag+(2.5 mM) significantly inhibited the activity of the enzyme. NBSI1 (1.0 mM), DNFB (0.5 mM) and PMSF (0.5 mM) completely inhibited the activity of the enzyme. The enzyme also showed muramidase activity for hydrolysis of Micrococcus lysodeikticus cell wall. The presence of chitinase in cabbage may function as a defense enzyme against potential pathogens.

Ammonium Sulfate↗