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Biomedical subjects

H C Wu

Publications and source records attributed to H C Wu.

At least 37 records · Page 2Linked to original sources
PubMed2001

Calcitonin receptor gene polymorphism: a possible genetic marker for patients with calcium oxalate stones.

OBJECTIVES: The formation of urinary stones is hypothesized to be associated with calcitonin receptors. The most commonly seen polymorphism is C/T at the 1377th nucleotide. Hence, these polymorphisms are being used as a genetic marker in the search for the cause of urolithiasis. METHODS: A normal control group of 105 healthy people and 102 patients with recurrent calcium oxalate stones were examined. The polymorphism was detected following a polymerase chain reaction-based and restriction analysis by AluI. An uncuttable length is 228 bp (CC) whereas two fragments of 120 and 108 bp are shown as cuttable lengths (TT). RESULTS: The results revealed significant differences between the normal individuals and the stone patients (p<0.01). The distribution of leucine (cuttable) homozygote in the stone group (2.0%) was higher than in the control group (0.0%). The odds ratio for the leucine allele of the calcitonin receptor gene in calcium oxalate stone disease is 5.634 (95% CI: 2.286--13.885). CONCLUSIONS: Results show that the polymorphism in the calcitonin receptor gene could be a genetic marker for urinary stone disease and therefore it is worthwhile pursuing further studies of the leucine allele of calcitonin receptor gene due to it is strongly correlated with stone disease.

Adult↗
PubMed2000

Age-dependent increase in C7-1 gene expression in rat frontal cortex.

We have previously reported that a fragment of mRNA, denoted as C7-1, which expression was significantly increased in the frontal cortex of aged rats. In the present study, we have cloned and sequenced the full length cDNA of the C7-1 gene. We have found that the open reading frame of this gene encoded a 463-amino-acid protein, which shared 84% identity in amino acid sequence with a subunit of vacuolar H(+)-ATPase (V-ATPase). Further Northern blot analysis revealed that there was an age-dependent increase in C7-1 gene expression in rat frontal cortex, but not in other brain areas. Moreover, application of C7-1 antisense oligonucleotide to cortical neuronal cultures markedly inhibited cell survival. These results together suggest that C7-1 is a marker for the aging process and that upregulation of C7-1 may be important in maintaining the normal function of V-ATPase during aging.

Aging↗
PubMed2000

Distributions of p53 codon 72 polymorphism in bladder cancer--proline form is prominent in invasive tumor.

Abnormal function of p53 is commonly associated with various cancer formations. High-grade and late-stage bladder cancers have been reported to have mutated or become inactive p53 when using immunohistochemical stains. Recently, p53 codon 72 polymorphism was extensively studied to determine the risk factors responsible for cancer formation. There was a general population of codon 72 sequence polymorphism of the wild type p53. A single base change from G to C caused the alteration of amino acid residue 72 from arginine to proline. The arginine form is considered to be a significant risk factor in the development of cancer. However, various reports had indicated discrepancies with regard to this polymorphism; some showed no significant difference between the control and cancer groups, while other series were associated with high risks in the proline form homozygotes. To resolve the undefined distribution of this polymorphism in bladder cancers, 58 patients with bladder cancer were enrolled onto this study. When checked using the Chi-squared test (P = 0.952) there were no differences between the control subjects and bladder cancer patients in the distribution of polymorphism. However, proline form homozygotes were more frequently found in the invasive group than the non-invasive group by Fisher's exact test (25% and 2.9%, respectively, P < 0.001). More than 70% of the non-invasive bladder cancers were the arginine form homozygotes. This result is consistent with those reported for hepatocellular carcinoma that showed a history of chronic liver disease and proline form homozygotes in a report by Yu et al. Our data suggest that proline form homozygotes are associated with invasive bladder cancer.

Adult↗
PubMed2000

Inhibition by vitamin C of DNA adduct formation and arylamine N-acetyltransferase activity in human bladder tumor cells.

Previous studies have already demonstrated the protective role of vitamin C (ascorbic acid) in certain types of cancer. This study reports on the effects of vitamin C on arylamine N-acetyltransferase (NAT) activity and DNA adduct formation in a human bladder tumor cell (T24) line. The activity of NAT was measured using high-performance liquid chromatography (HPLC), by assaying for the amounts of acetylated 2-aminofluorene (AF) and p-aminobenzoic acid (PABA) and the remaining amounts of AF and PABA. T24 cells were used for examining NAT activity and carcinogen DNA adduct formation. The results demonstrated that NAT activity and 2-aminofluorene DNA adduct formation in T24 cells were inhibited and decreased by vitamin C in a dose-dependent manner. The apparent kinetic parameters (apparent values of Km and Vmax) from T24 cells were also determined with and without vitamin C cotreatment. The data also indicated that vitamin C decreased the apparent values of Km and Vmax from T24 cells.

4-Aminobenzoic Acid↗
PubMed2000

Effects of butylated hydroxyanisole and butylated hydroxytoluene on DNA adduct formation and arylamines N-acetyltransferase activity in PC-3 cells (human prostate tumor) in vitro.

The effects of butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) on the N-acetyltransferase (NAT) activity and DNA adduct formation in PC-3 cells (human prostate tumor) was studied. PC-3 cells were placed into tissue culture flasks and grown in an incubator as cytosols and intact cells. The BHA or BHT were added to the cytosols and intact cells. The NAT activity in cytosol and intact PC-3 cells were measured by HPLC assaying exhibited for the amounts of N-acetyl-2-aminofluorene and N-acetyl-p-aminobenzoic acid, 2-aminofluorene and p-aminobenzoic acid. The NAT activity in PC-3 cells and cytosols were inhibited by BHA or BHT in a dose-dependent manner; that is, the higher the concentrations of BHA or BHT the higher inhibition of NAT activity. The NAT values of K(m) and V(max) from PC-3 cells were also decreased by BHA or BHT in both cytosols and intact cells. The data also demonstrated concomitant exposure to BHA or BHT decreased AF-DNA adduct formation which was seen in the PC-3 cells. In addition, the formation of DNA adduct was decreased after BHA or BHT exposure. These findings suggested the usefulness of using human cultured PC-3 cells for assessing arylamine-induced DNA adduct formation. Furthermore, the findings illustrate how effectively BHA or BHT reduce the adduct formation.

Arylamine N-Acetyltransferase↗
PubMed2000

Response of nasopharyngeal carcinoma cells to Epstein-Barr virus infection in vitro.

Many nasopharyngeal carcinoma (NPC) biopsy specimens contain Epstein-Barr virus (EBV). However, the response of NPC cells to EBV infection in vitro and in vivo is not well characterized. In this experiment we infected NPC cells with EBV particles through endocytosis of a complex of EBV immunoglobulin A (IgA) secretory component (SC) protein to observe the response of host cells to the foreign viral infection in vitro. We found that EBV particles were endocytosed and stabilized in NPC nuclei 24 hours after infection; the EBV genomes were then gradually decreased after serial passages within 3 to 4 weeks by the following pathway: the EBV genomes first moved toward the nuclear envelope from the center of the nucleus; after crossing the nuclear envelope, they moved into the cytoplasm and toward the plasma membrane and were discharged by exocytosis. At the 10th day of EBV infection, EBV-latent membrane protein-1 and Epstein-Barr nuclear antigen (EBNA)-1 protein expressions could be detected, but not EBV-viral capsid antigen. Observation of EBNA-1 protein and host growth factor and cytokine gene expressions in the weeks after incubation revealed that the EBNA-1 protein expression was decreased proportionally with decrease of EBV genome. The mRNA expression of epithelial growth factor receptor, transforming growth factor (TGF)-alpha, interleukin (IL)-1beta, IL-6, and granulocyte-macrophage colony-stimulating factor increased within 1 to 2 weeks after infection, and gradually recovered to the original level at 3 to 4 weeks, whereas the mRNAs of TGFbeta1, TGFbeta receptor type I (TGFbetaRI), TGFbetaR type II, IL-8, and tumor necrosis factor-alpha remained unchanged. It is concluded that in vitro EBV infection in NPC cells results in increase of certain growth factor and cytokine gene expressions in host cells. The change in gene expression returns to the original level approximately 3 to 4 weeks after infection because of exocytosis of EBV DNA by the infected cells through an unidentified mechanism.

Base Sequence↗
PubMed2000

Potential dengue virus-triggered apoptotic pathway in human neuroblastoma cells: arachidonic acid, superoxide anion, and NF-kappaB are sequentially involved.

Direct in vivo evidence for the susceptibility of human neuronal cells to dengue virus has not been reported. In this study, we demonstrated that type 2 dengue (DEN-2) virus infection induced extensive apoptosis in the human neuroblastoma cell line SK-N-SH. Phospholipase A(2) (PLA(2)) was activated by DEN-2 infection, which led to the generation of arachidonic acid (AA). Inhibition of PLA(2) activity by the PLA(2) inhibitors, AACOCF(3) and ONO-RS-082, diminished DEN-2 virus-induced apoptosis. In contrast, the cyclooxygenase inhibitors aspirin and indomethacin, thought to increase AA accumulation by blocking AA catabolism, enhanced apoptosis. Exogenous AA induced apoptosis in a dose-dependent manner. Superoxide anion, which is thought to be generated through the AA-activated NADPH oxidase, was increased after infection. Pretreatment with superoxide dismutase (SOD) protected cells against DEN-2 virus-induced apoptosis. Furthermore, generation of superoxide anion was blocked by AACOCF(3). In addition, the transcription factors, NF-kappaB and c-Jun, were found to be activated after DEN-2 virus infection. However, pretreatment of cells with oligodeoxynucleotides containing NF-kappaB, but not c-Jun, binding sites (transcription factor decoy) strongly prevented dengue virus-induced apoptosis. The finding that AACOCF(3) and SOD significantly block activation of NF-kappaB suggests that this activation is derived from the AA-superoxide anion pathway. Our results indicate that DEN-2 virus infection of human neuroblastoma cells triggers an apoptotic pathway through PLA(2) activation to superoxide anion generation and subsequently to NF-kappaB activation. This apoptotic effect can be either directly derived from the action of AA and superoxide anion on mitochondria or indirectly derived from the products of apoptosis-related genes activated by NF-kappaB.

Animals↗
PubMed2000

Transrectal ultrasonographic findings in patients with hemospermia.

BACKGROUND: Hemospermia causes anxiety in many men. Its etiology includes inflammatory disorders, vascular lesions, malignancies and congenital anomalies. With the advent of modern transrectal ultrasonography (TRUS) and magnetic resonance imaging technology, we can now visualize the internal structures of the seminal vesicles and prostate, and identify a more accurate etiology for hemospermia. This study was performed to assess the efficacy of TRUS in the evaluation of hemospermia. METHODS: TRUS was used to evaluate 40 patients with hemospermia. Patients' ages ranged from 20 to 72 years, with an average age of 41 years. The duration of symptoms was 3 days to 10 years, (average age 12.4 months). Apart from three patients with hepatitis, there was no major illness found in the medical histories. TRUS was performed with a B & K, type 3535 transrectal transducer device, with an 1850 multiplane probe. RESULTS: TRUS revealed abnormalities in 33 (83%) of 40 patients, which included ejaculatory duct cysts, müllerian duct cysts, asymmetric seminal vesicle dilatation, preprostatic vein engorgement and prostatic enlargement. There were stones in the ejaculatory ducts, ejaculatory duct cysts, müllerian duct cysts or prostate. Nine patients with prostatic stones were under 40 years-of-age. Other than the development of stones, there were no significant differences between patients less than 40 years-of-age and those more than 40 years old. CONCLUSIONS: The results suggest that TRUS is an effective method for examining the seminal vesicles, ejaculatory duct and prostate complex. Sonoguided aspiration, injection of contrast medium or biopsy can further help to differentiate the nature of hemospermia.

Adult↗
PubMed2000

Does Ser364Pro mutation of connexin 43 exist in Taiwanese patients with Ivemark syndrome?

BACKGROUND: A previous study by Britz-Cunningham et al (N Engl J Med, 1995) indicated that a mutation of the connexin 43 (CX43) gap junction gene might be responsible for Ivemark syndrome. Ser364Pro substitution (TCA-->CCA) is the most common mutation located in the cytoplasmic tail domain of CX43. This domain may be an important part of the conductance channel of the gap junction. It may, therefore, result in heart anomalies and situs inversus during embryonic development, resulting in Ivemark syndrome. METHODS: We investigated 10 patients with Ivemark syndrome, 10 healthy individuals, one patient with Kartagener syndrome and one with polysplenia and situs inversus but without heart anomaly for this mutation. Seminested polymerase chain reaction (PCR) was performed using a DNA template from DNA extracted from peripheral blood cells. Direct sequencing was done after purification of the second round of PCR products. Then, the sequence was compared with the last 402 bp of the cDNA-coding region of CX43. RESULTS: No base changes were found in the patients with Ivemark syndrome or other patient groups at the previously reported CX43 residues of Thr326, Gln352, Ser364, Ser365 and Ser373. CONCLUSIONS: The results indicate that Ser364Pro mutation of CX43 did not exist in the 10 Taiwanese patients with Ivemark syndrome. Other genes responsible for the Ivemark syndrome should be further investigated.

Abnormalities, Multiple↗
PubMed1999

A patient with bilateral primary adrenal lymphoma, presenting with fever of unknown origin and achieving long-term disease-free survival after resection and chemotherapy.

Primary adrenal lymphoma is extremely rare. We describe a 64-year-old female patient who presented with fever of unknown origin. Imaging studies demonstrated bilateral bulky adrenal masses. She underwent bilateral adrenalectomy and the pathological diagnosis was large cell immunoblastic (B-cell) lymphoma. She received adjuvant combination chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisolone in the following 6 months. She has been relapse free for 52 months. To the best of our knowledge, this case has the longest disease-free survival among those reported. The present case indicated that primary adrenal lymphoma should be included in the differential diagnosis of fever of unknown origin and/or suprarenal mass. Chemotherapy following surgical resection may be considered the treatment of choice.

Adrenal Cortex↗
PubMed1999

Cryopreservation of sperm from the endangered formosan landlocked salmon (Oncorhynchus masou formosanus).

The Formosan landlocked salmon (Oncorhynchus masou formosanus) are at a high risk of extinction, and the sustained maintenance of the population will soon depend on aquaculture systems, which use cryopreservation of spermatozoa to increase genetic diversity. We investigated the effectiveness of dimethyl sulfoxide (DMSO), dimethyl-acetamide (DMA), and methanol as cryoprotectants in combination with 300 mM glucose as extender on the freezing of Formosan landlocked salmon spermatozoa. We also evaluated the morphological changes of Formosan landlocked salmon spermatozoa after their immediate dilution in the 300 mM glucose-DMSO extender and after freeze-thawing. The spermatozoa frozen with DMSO as a cryoprotectant showed significantly higher post-thaw motility and fertility than spermatozoa frozen with DMA or methanol. The fertilization capacity of frozen-thawed Formosan landlocked salmon was comparable to that of fresh spermatozoa. Intersubspecies fertilization trials between cryopreserved Formosan landlocked salmon spermatozoa and Amago salmon eggs showed high fertilization rates. Based on the findings, the potential value of using sperm bank to safeguard this endangered species is discussed.

Animals↗
PubMed1999

Transient absorption changes in vivo during photodynamic therapy with pulsed-laser light.

High intensity pulsed-laser light can be used to excite absorbing molecules to transient states in large proportions. The laser-induced spectral changes can be characterized by transient changes in light propagation; through the tissue provided the excited states of these molecules have altered absorption spectra. Characterization of these transient changes may then be used to exploit new mechanisms in photosensitization and/or to optimize photobiological effects. In this study, transmittance and reflectance were measured as a function of laser pulse energy, from tissue-simulating media as well as in rat muscle and liver slices, both with and without the photosensitizer benzoporphyrin derivative monoacid (BPD-MA) present. There was a transient decrease in absorption from the photosensitizer at peak pulse irradiance in the range of 100-1000 W cm(-2). The depth of photodynamic treatment-induced tissue necrosis was measured in a subcutaneous prostate cancer model in Copenhagen rats. A comparison between continuous wave irradiation and pulsed irradiation with the same average incident irradiance showed no statistically significant difference in the depth of necrosis at 48 h after irradiation. These results indicate that photosensitizer population-state changes are measurable in tissues and may provide a method for measuring triplet-state properties of photosensitizer in vivo, but for BPD-MA at clinically used concentrations these changes do not significantly affect the depth of photodynamically-induced tissue damage.

Absorption↗
PubMed1999

Identification and characterization of a new lipoprotein, NlpI, in Escherichia coli K-12.

We report here the identification of a new lipoprotein, NlpI, in Escherichia coli K-12. The NlpI structural gene (nlpI) is located between the genes pnp (polynucleotide phosphorylase) and deaD (RNA helicase) at 71 min on the E. coli chromosome. The nlpI gene encodes a putative polypeptide of approximately 34 kDa, and multiple lines of evidence clearly demonstrate that NlpI is indeed a lipoprotein. An nlpI::cm mutation rendered growth of the cells osmotically sensitive, and incubation of the insertion mutant at an elevated temperature resulted in the formation of filaments. The altered phenotype of the mutant was a direct consequence of the mutation in nlpI, since it was complemented by the wild-type nlpI gene alone. Overexpression of the unaltered nlpI gene in wild-type cells resulted in the loss of the rod morphology and the formation of single prolate ellipsoids and pairs of prolate ellipsoids joined by partial constrictions. NlpI may be important for an as-yet-undefined step in the overall process of cell division.

Amino Acid Sequence↗
PubMed1999

Effects of the butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) on the arylamines N-acetyltransferase activity in rat white blood cells.

Butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) were used to determine any effects on the N-acetyltransferase (NAT) activity in rat whole blood and white blood cells as measured by high performance liquid chromatography assay for the amounts of N-acetyl-2-aminofluorene (AAF) and 2-aminofluorene (AF). Two assay systems were performed, one with cellular cytosols, the other with intact white blood cells. The NAT activity in the whole blood and white blood cell cytosols was suppressed by BHA and BHT in a dose-dependent manner, i.e. the higher the concentrations of BHA and BHT, the higher the inhibition of NAT activity. Time-course experiments showed that NAT activity measured from the intact white blood cells was inhibited by BHA and BHT up to 24 h. The results suggest that BHA and BHT suppressed AF acetylation in rat blood with intact white blood cells.

Acetylation↗
PubMed1998

Photodynamic therapy of orthotopic prostate cancer with benzoporphyrin derivative: local control and distant metastasis.

This is the first report of photodynamic therapy (PDT) in an orthotopic prostate tumor model and shows that PDT combined with surgery (tumor bed sterilization) gave significant local control of the primary tumor and significant reduction in distant metastases. By contrast, either treatment alone (surgery or PDT) gave relatively poorer local control, and PDT gave a significant increase in the mean number of lung metastases. The MatLyLu variant of the Dunning 3327 rat prostate cancer cell line, which has been selected to be metastatic to lymph nodes and lungs, was injected into the ventral lobe of the rat prostate. After 7 days, tumors were either treated by surgical removal of the ventral lobe, PDT with liposomal benzoporphyrin derivative monoacid ring A, or a combination of surgery, followed by PDT of the tumor bed. Results after 21 days showed a reduction in prostate tumor weight in all groups compared with controls, which became highly significant only for the combination group (17% of control mean tumor weight; P < 0.001; 7 of 13 clinical complete responses). The combination treatment also led to a reduction in lymph node metastasis and reductions in both the frequency and mean number of lung metastases compared with other treatment groups. The PDT-alone group, however, had a mean number of lung metastases per animal, which was nine times the control group and 34 times the combination group. These findings suggest that a tumor bed sterilization approach may be promising for locally advanced prostate cancer and suggest that factors other than local control may need to be evaluated when considering PDT for primary prostate cancer.

Adenocarcinoma↗