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Biomedical subjects

Y H Hsu

Publications and source records attributed to Y H Hsu.

At least 19 recordsLinked to original sources
PubMed2004

The effect of hyperbaric oxygen on human oral cancer cells.

Discoveries of the beneficial cellular and biochemical effects have strengthened the rationale for the administration of hyperbaric oxygen therapy (HBO2) as an adjunctive therapy for the treatment of osteoradionecrosis (ORN). Malignancies, however, are considered a contraindication for HBO2 because of the possible tumor-promoting effects. The aim of this study was to examine the effects of HBO2 therapy on tumor weight, and to measure the progression of apoptosis and tumor cell proliferating activity in a cultured human oral cancer cell line. Twenty 5-week-old male NODscid mice underwent daily HBO2 of 2.5 atm abs, 90 minutes for 20 treatments. The control group, n = 20, did not undergo HBO2 and tumor weight, apoptosis index, and proliferating activity parameters were compared between the two groups. The results showed no significant differences (p < 0.05) in the whole-body weights, tumor weights, apoptotic index or proliferating activity index between the two groups. By using the apoptosis and proliferating activity assays which were better indicators of tumor cell growth than tumor weight alone, our results suggest that the clinical application of HBO2 does not promote the growth or proliferation of human oral cancer cells.

Animals↗
PubMed2001

The partial purified RNA-dependent RNA polymerases from bamboo mosaic potexvirus and potato virus X infected plants containing the template-dependent activities.

RNA-dependent RNA polymerases (RdRp) isolated from bamboo mosaic potexvirus (BaMV) and potato virus X infected Nicotiana benthamiana plants and solubilized with the detergent NP-40, generated a full-length genomic and two subgenomic double-stranded RNAs of respective viruses in an in vitro RdRp assay containing endogenous RNA templates. Template-dependent and species-specific RdRp activity could be detected after the removal of endogenous RNA templates. The 3' untranslated regions (UTR) containing a stretch of 40 adenylate residues were shown to be an efficient exogenous RNA template for in vitro RdRp reactions. Solution hybridization and nuclease digestion studies revealed that the products transcribed in vitro were minus-sense. Besides using the 3' UTR for minus-sense RNA synthesis, the BaMV RdRp can also recognize 3' terminal 77 nucleotides of the minus-strand for plus-sense RNA synthesis. Promoter studies with BaMV RdRp showed that domain D containing the potexviral hexamer motif of the 3' UTR would be the major contributor of minus-sense RNA synthesis in vitro. On the other hand, the pseudoknot domain containing the poly(A) sequences would be sufficient for minus-sense RNA synthesis.

3' Untranslated Regions↗
PubMed2001

Hyperbaric oxygen treatment decreases post-ischemic neurotrophin-3 mRNA down-regulation in the rat hippocampus.

The therapeutic effect of hyperbaric oxygen (HBO) on ischemic injury was investigated using in situ hybridization to detect the mRNA expression of neurotrophin-3 (NT-3), which is thought to play a crucial role in protecting against neuronal death induced by brain ischemia. The rats under investigation were subjected to 10 min transient forebrain ischemia, and subsequently exposed to HBO (100% oxygen, 2.5 atm absolute) for 2 h. Levels of NT-3 mRNA in the CA1, CA2 and CA3 regions, and the dentate gyrus of the hippocampus were measured after various reperfusion periods. Neuronal death in the hippocampal CA1 region was also measured by Nissl staining, seven days post ischemia. The results demonstrated that HBO treatment significantly reduced the ischemia-induced down-regulation of the NT-3 mRNA level at 4 h post ischemia, and significantly increased cell survival 7 days after reperfusion. The findings suggest that an HBO treatment maintaining the NT-3 mRNA level in the hippocampus can be beneficial to the ischemic brain within a certain time frame.

Animals↗
PubMed2001

Incidence of transitional cell carcinoma and arsenic in drinking water: a follow-up study of 8,102 residents in an arseniasis-endemic area in northeastern Taiwan.

A significant association between ingested arsenic and bladder cancer has been reported in an arseniasis-endemic area in southwestern Taiwan, where many households share only a few wells in their villages. In another arseniasis-endemic area in northeastern Taiwan, each household has its own well for obtaining drinking water. In 1991-1994, the authors examined risk of transitional cell carcinoma (TCC) in relation to ingested arsenic in a cohort of 8,102 residents in northeastern Taiwan. Estimation of each study subject's individual exposure to inorganic arsenic was based on the arsenic concentration in his or her own well water, which was determined by hydride generation combined with atomic absorption spectrometry. Information on duration of consumption of the well water was obtained through standardized questionnaire interviews. The occurrence of urinary tract cancers was ascertained by follow-up interview and by data linkage with community hospital records, the national death certification profile, and the cancer registry profile. Cox proportional hazards regression analysis was used to estimate multivariate-adjusted relative risks and 95% confidence intervals. There was a significantly increased incidence of urinary cancers for the study cohort compared with the general population in Taiwan (standardized incidence ratio = 2.05; 95% confidence interval (CI): 1.22, 3.24). A significant dose-response relation between risk of cancers of the urinary organs, especially TCC, and indices of arsenic exposure was observed after adjustment for age, sex, and cigarette smoking. The multivariate-adjusted relative risks of developing TCC were 1.9, 8.2, and 15.3 for arsenic concentrations of 10.1-50.0, 50.1-100, and >100 microg/liter, respectively, compared with the referent level of < or =10.0 microg/liter.

Adult↗
PubMed2001

Characterization of the AdoMet-dependent guanylyltransferase activity that is associated with the N terminus of bamboo mosaic virus replicase.

Bamboo mosaic virus (BaMV), a member of the potexvirus group, infects primarily members of the Bambusoideae. Open reading frame 1 (ORF1) of BaMV encodes a 155-kDa polypeptide that has long been postulated to be a replicase involved in the replication and formation of the cap structure at the 5' end of the viral genome. To identify and characterize the enzymatic activities associated with the N-terminal domain of the BaMV ORF1 protein, the intact replicase and two C-terminally truncated proteins were expressed in Saccharomyces cerevisiae. All three versions of BaMV ORF1 proteins could be radiolabeled by [alpha-(32)P]GTP, which is a characteristic of guanylyltransferase activity. The presence of S-adenosylmethionine (AdoMet) was essential for this enzymatic activity. Thin-layer chromatography analysis suggests that the radiolabeled moiety linked to the N-terminal domain of the BaMV ORF1 protein is m(7)GMP. The N-terminal domain also exhibited methyltransferase activity that catalyzes the transfer of the [(3)H]methyl group from AdoMet to GTP or guanylylimidodiphosphate. Therefore, during cap structure formation in BaMV, methylation of GTP may occur prior to transguanylation as for alphaviruses and brome mosaic virus. This study establishes the association of RNA capping activity with the N-terminal domain of the replicase of potexviruses and further supports the idea that the reaction sequence of RNA capping is conserved throughout the alphavirus-like superfamily of RNA viruses.

Amino Acid Sequence↗
PubMed2001

The helicase-like domain of plant potexvirus replicase participates in formation of RNA 5' cap structure by exhibiting RNA 5'-triphosphatase activity.

Open reading frame 1 (ORF1) of potexviruses encodes a viral replicase comprising three functional domains: a capping enzyme at the N terminus, a putative helicase in the middle, and a polymerase at the C terminus. To verify the enzymatic activities associated with the putative helicase domain, the corresponding cDNA fragment from bamboo mosaic virus (BaMV) was cloned into vector pET32 and the protein was expressed in Escherichia coli and purified by metal affinity chromatography. An activity assay confirmed that the putative helicase domain has nucleoside triphosphatase activity. We found that it also possesses an RNA 5'-triphosphatase activity that specifically removes the gamma phosphate from the 5' end of RNA. Both enzymatic activities were abolished by the mutation of the nucleoside triphosphate-binding motif (GKS), suggesting that they have a common catalytic site. A typical m(7)GpppG cap structure was formed at the 5' end of the RNA substrate when the substrate was treated sequentially with the putative helicase domain and the N-terminal capping enzyme, indicating that the putative helicase domain is truly involved in the process of cap formation by exhibiting its RNA 5'-triphosphatase activity.

Acid Anhydride Hydrolases↗
PubMed2001

Sequences at the 3' untranslated region of bamboo mosaic potexvirus RNA interact with the viral RNA-dependent RNA polymerase.

The 3' untranslated region (UTR) of bamboo mosaic potexvirus (BaMV) genomic RNA was found to fold into a series of stem-loop structures including a pseudoknot structure. These structures were demonstrated to be important for viral RNA replication and were believed to be recognized by the replicase (C.-P. Cheng and C.-H. Tsai, J. Mol. Biol. 288:555-565, 1999). Electrophoretic mobility shift and competition assays have now been used to demonstrate that the Escherichia coli-expressed RNA-dependent RNA polymerase domain (Delta 893) derived from BaMV open reading frame 1 could specifically bind to the 3' UTR of BaMV RNA. No competition was observed when bovine liver tRNAs or poly(I)(C) double-stranded homopolymers were used as competitors, and the cucumber mosaic virus 3' UTR was a less efficient competitor. Competition analysis with different regions of the BaMV 3' UTR showed that Delta 893 binds to at least two independent RNA binding sites, stem-loop D and the poly(A) tail. Footprinting analysis revealed that Delta 893 could protect the sequences at loop D containing the potexviral conserved hexamer motif and part of the stem of domain D from chemical cleavage.

3' Untranslated Regions↗
PubMed2001

Prenatal diagnosis of persistent fetal bradycardia: report of four cases.

Persistent fetal bradycardia is infrequent in prenatal life and difficult to manage optimally. It is generally attributable to sinus bradycardia due to fetal distress, blocked atrial extrasystoles, and congenital complete heart block. We reported four cases of persistent fetal bradycardia from 1995 to 1999 in our hospital. The first, second, and third cases of sustained fetal bradycardia had congenital complete heart block with positive titers for anti-Ro/SSA antibodies in both mothers and fetuses. Because of progressive fetal hydrops in the second case, the pregnancy was terminated. The first and third cases were isolated congenital complete heart block without structural anomaly. After prenatal examination the babies were followed up closely until term and both had a good prognosis without any implantation of pacemaker. In the fourth case there was no clinically known etiology associated with sustained fetal bradycardia. The fetal heart rate returned to normal after 6 weeks of follow-up and the baby was delivered without any cardiac problems. Congenital complete heart block is the most common cause of persistent fetal bradycardia. Prenatal detailed monitoring until delivery is necessary before heart failure develops. Treatment strategies (corticosteroids, ritodrine, and plasmapheresis) are debatable and may include prophylactic therapy for high-risk pregnant women.

Adrenal Cortex Hormones↗
PubMed2001

Clinicopathologic study of Kaposi's sarcoma and strain analysis of human herpesvirus 8 (HHV-8) DNA in the Hua-Lien area of eastern Taiwan.

BACKGROUND AND PURPOSE: Kaposi's sarcoma (KS) is a spindle cell malignancy of endothelial cell origin. The tumor has been demonstrated to be associated with human herpesvirus 8 (HHV-8) or Kaposi's sarcoma-associated herpesvirus-like virus (KSHV). Previous studies have revealed the distribution of unique viral strains in different ethnic populations. Eastern Taiwan has an ethnically mixed population with a relatively high incidence of KS. This study was designed to characterize the clinicopathologic features of KS and to evaluate the HHV-8 strain distribution in the Hua-Lien area of Eastern Taiwan. METHODS: Clinical records and laboratory data were collected from 15 cases of KS diagnosed and treated between 1993 and 1999 in Tzu-Chi General Hospital. For nine cases, paraffin blocks were available for the molecular study of HHV-8. HHV-8 genomic variation was analyzed using polymerase chain reaction nucleotide sequencing of ORF26 and ORF75 of HHV-8 genomes derived from different subgroups of KS. RESULTS: Among the 15 patients with KS, two had AIDS-associated disease, four had gouty arthritis and psoriasis and were receiving corticosteroid therapy (iatrogenic type), and nine had classical KS. Nine of the 15 cases occurred in aborigines, including one with AIDS-associated disease, four with iatrogenic disease, and four with classical disease. Among the nine cases for which tissue was available for DNA analysis, eight were positive for HHV-8 DNA. Sequence analysis revealed that the C strain occurred in three Han Chinese KS patients, whereas a hitherto rarely described strain (strain D) occurred in all four aborigines tested (including one with AIDS-associated KS) and one Han Chinese with AIDS from Burma. CONCLUSION: This study found a high proportion of iatrogenic KS and the finding of a rarely described strain D virus in Eastern Taiwan aborigines. Our studies further confirm the distribution of different types of KS and virus strains in different ethnic populations.

Adult↗
PubMed2001

Immunohistochemical localization of deleted-in-colon-cancer (DCC) protein in human epithelial, neural, and neuro-endocrine tissues in paraffin sections with antigen retrieval.

A gene called deleted in colon cancer (DCC) has been identified on a region of chromosome 18, which is deleted in 70% of colorectal cancers. The DCC gene encodes a protein belonging to the immunoglobulin superfamily with similarity to the N-CAM transmembrane proteins, and it is a putative tumor-suppressor gene. Alternative splicing of transcripts of transmembrane proteins, including N-CAM, is know to occur, resulting in different isoforms of the protein. Using a polyclonal antibody against the DCC gene product, we have demonstrated, by antigen retrieval immunostaining, the presence of a DCC protein isoform on the cell surface of goblet cells in the G-I tract, cytoplasm of squamous epithelium in the skin & esophagus and transitional epithelium in the urinary bladder, ductal glandular epithelium of endometrium, endocervix, prostate, gall bladder and breast, cytoplasm of neuron in the cerebral cortex and Purkinje cells in the cerebellum. In addition, we also demonstrated DCC protein expression in neuroendocrine cells including argentaffin cells of the stomach, small intestine, appendix and colon, C cells of thyroid gland, chromaffin cells of the adrenal gland, islets of Langerhans in the pancreas and neurons of the sympathetic ganglion. This restrictive distribution suggests the DCC gene products may be abundant expression in neuroendocrine cells of human tissue.

Animals↗
PubMed2001

Isolated craniosynostosis: prenatal ultrasound of scaphocephaly with polyhydramnios.

Craniosynostosis is an abnormal shape or dimension of the skull caused by premature closure of one or more skull sutures. It includes scaphocephaly, brachycephaly, oxycephaly, plagiocephaly, trigonocephaly, turricephaly, and a cloverleaf-shaped head. The only cases of craniosynostosis that have been reported concern fetuses with complex and marked craniosynostosis syndromes such as acrocraniofacial dysostosis, Apert's syndrome, Beare-Stevenson cutis gyratum syndrome, Calabro's syndrome, etc. Isolated or simple craniosynostosis, however, is a developmental anomaly rarely found on routine ultrasound examination. We present a case that was diagnosed as scaphocephaly with moderate polyhydramnios by prenatal ultrasound. No other structural anomaly was detected, and the karyotyping was normal. So isolated sagittal craniosynostosis was diagnosed prenatally and was confirmed by postnatal skull radiography as well as 3-dimensional computed tomography. The infant underwent bilateral parietal craniectomy at the age of 3 months. He obtained a good result with no mental problems 4 years after the operation. To our knowledge, this is the second report on the prenatal detection of an isolated form of craniosynostosis.

Adult↗
PubMed2000

Functional analyses and identification of two arginine residues essential to the ATP-utilizing activity of the triple gene block protein 1 of bamboo mosaic potexvirus.

The TGBp1 of bamboo mosaic potexvirus (BaMV) is encoded by the first overlapping gene of the triple-gene-block (TGB), whose products are thought to play roles in virus movement between plant cells. This protein forms cytoplasmic inclusions associated with virus particles in the BaMV-infected tissues. It has been proposed that the inclusion is one of the active forms of TGBp1. To prove this idea, we purified the TGBp1 inclusions from both the BaMV-infected Chenopodium quinoa and Escherichia coli cells overexpressing this protein to test some of their biochemical activities. We found that the TGBp1 inclusions isolated from the infected plant leaves, but not from E. coli, possess the NTP-binding and NTPase activities. However, they lack the RNA-binding activity possessed by the soluble TGBp1. These results indicate that the TGBp1 proteins in the BaMV-infected tissues assume two different functional forms. Mutational analyses and competition experiments show that the two arginine residues, Arg-16 and Arg-21, essential to RNA binding, are also required for the ATP-utilizing activity of the soluble TGBp1. This indicates that a same-structure motif is required for the two functions of the soluble TGBp1. The location of the two arginine residues outside the seven conserved motifs of the NTP-utilizing superfamily I RNA helicases, to which TGBp1 belongs, suggests that an extra-structure motif, besides the seven conserved ones, is required for the NTP-utilizing activity of the TGBp1 protein of BaMV.

Acid Anhydride Hydrolases↗
PubMed2000

Generation of subgenomic RNA directed by a satellite RNA associated with bamboo mosaic potexvirus: analyses of potexvirus subgenomic RNA promoter.

Satellite RNA of bamboo mosaic potexvirus (satBaMV), a single-stranded positive-sense RNA encoding a nonstructural protein of 20 kDa (P20), depends on bamboo mosaic potexvirus (BaMV) for replication and encapsidation. A full-length cDNA clone of satBaMV was used to examine the sequences required for the synthesis of potexvirus subgenomic RNAs (sgRNAs). Subgenomic promoter-like sequences (SGPs), 107 nucleotides (nt) upstream from the capsid protein (CP) gene of BaMV-V, were inserted upstream of the start codon of the P20 gene of satBaMV. Insertion of SGPs gave rise to the synthesis of sgRNA of satBaMV in protoplasts of Nicotiana benthamiana and leaves of Chenopodium quinoa when coinoculated with BaMV-V genomic RNA. Moreover, both the satBaMV cassette and its sgRNA were encapsidated. From analysis of the SGPs by deletion mutation, we concluded that an SGP contains one core promoterlike sequence (nt -30 through +16), two upstream enhancers (nt -59 through -31 and -91 through -60), and one downstream enhancer (nt +17 through +52), when the transcription initiation site is taken as +1. Site-directed mutagenesis and compensatory mutation to disrupt and restore potential base pairing in the core promoter-like sequence suggest that the stem-loop structure is important for the function of SGP in vivo. Likewise, the insertion of a putative SGP of the BaMV open reading frame 2 gene or a heterologous SGP of potato virus X resulted in generation of an sgRNA. The satBaMV cassette should be a useful tool to gain insight into sequences required for the synthesis of potexvirus sgRNAs.

5' Untranslated Regions↗
PubMed2000

TT virus infection among hemodialysis patients at a medical center in Taiwan.

Although the association between TT virus (TTV) infection and hepatitis is controversial, the high prevalence of TTV infection in healthy blood donors and even higher rate among frequently transfused patients poses a potential threat to public health and clinical care. In addition, there is a lack of data concerning the prevalence and mode of transmission of TTV infection in different subpopulations in Taiwan. In the present study, we investigated the prevalence of TTV infection in 111 uremic patients receiving regular hemodialysis in a single hospital in Taiwan. Blood samples were collected and analyzed using a seminested polymerase chain reaction (PCR) designed to amplify a 271 base-pair DNA fragment. The results show that the overall TTV positive rate in uremic patients in our hospital was 61% (68/111), which was much higher than the reported TTV prevalence rate among the normal population (ranging from 1%-12%). The results of analysis of the demographic and clinical characteristics of the patients indicate that blood transfusion may play an important role in TTV transmission (p < 0.05). In addition, the hepatitis B positive rate was significantly lower in TTV positive patients. However, liver function tests were not significantly different between TTV positive and TTV negative patients. The results of the present study suggest that blood transfusion plays an important role in TTV transmission in uremic patients.

Adult↗
PubMed2000

The DCC protein expression in breast carcinoma.

Inactivation of the gene "deleted in colon cancer" (DCC) on chromosome 18 is known to be associated with the tumorigenesis and metastasis of colorectal cancer. In the present study, we investigated the expression of DCC, P53 and HER-2/neu product in surgical specimens from 79 patients with invasive breast cancer by immunohistochemistry staining and found the expression of DCC to be decreased in 42 tumors (52%). Overexpression of HER-2/neu and P53 was detected in 29 (36.8%) and 26 (32.9%) of this 79 breast cancer specimens, respectively. To evaluate the outcomes of the 79 breast cancer patients, we followed up the patients during the period from May 1990 to August 1998. The average length of follow-up was 52 months (ranging from 4 to 94 months). Patients with tumors having a combination of DCC-negative and HER-2/neu overexpression showed a marginal influence on survival time of breast cancer (P = 0.06). However, patients with tumors having a combination of DCC-negative and P53 overexpression showed no influence of these on survival time of breast cancer (P = 0.36). These findings suggest that a decreased DCC expression and HER-2/neu overexpression may influence the prognosis of breast cancer.

Breast Neoplasms↗
PubMed2000

Effects of induction anesthetic agents on outcome of assisted reproductive technology: a comparison of propofol and thiopental sodium.

BACKGROUND: The use of propofol, as compared to barbiturates (e.g. thiopental), for short surgical procedures has been associated with more rapid recovery from the procedure. Propofol, an intravenous anesthetic drug, is frequently used as an adjunct to transvaginal oocyte retrieval but little is known about its effects upon fertilization, embryo development, and pregnancy rate when used drug the for induction of general anesthesia. This study was conducted to compare the outcome of assisted reproductive technology (ART) with the use of propofol versus thiopental sodium for the induction of general anesthesia during oocyte retrieval. METHODS: In this retrospective study, 92 cases of infertile patients who underwent oocyte retrieval under the induction of general anesthesia with, respectively, either propofol (Group I, 72 cases) or thiopental sodium (Group II, 20 cases) were compared for fertilization rate, cleavage rate, and pregnancy rate. RESULTS: The fertilization rate was 68.9% for Group I and 66.7% for group II (p = 0.614). The cleavage rate was 96.5% for Group I and 94.8% for Group II (p = 0.294). The rate of good embryo grading and poor embryo grading was, respectively, 85.1% and 14.9% for Group I, versus 85.7% and 14.3% for Group II (p = 0.887). The pregnancy rate was 30.5% for Group I and 20.0% for Group II (p = 0.354). The implantation rate and abortion rate was, respectively, 9.1% and 18.2% for Group I versus 7.2% and 25.0% for Group II (implantation rate, p = 0.590; abortion rate, p = 0.600). CONCLUSION: There were no significant differences between these two groups for fertilization rate, cleavage rate, pregnancy rate, implantation rate and abortion rate. We suggest cautious use of propofol for the procedure of oocyte retrieval despite its associated more rapid post-operative recovery including less nausea/vomiting.

Anesthetics, Intravenous↗
PubMed2000

Do the CK18 related proteins change in general in epithelial cancers?

The modulation of cytokeratin 18 during tumor transformation in hepatoma had been previously recognized through a series of biochemical and immunological approaches. Expression of cytokeratin 18 in transitional cell carcinoma comparing with hepatoma was investigated using the hepatoma transformation model. CK18 related molecules were found. In the present study, we design various epithelial cancers with the same model. CK18 related molecules were all evident. Therefore, we suggest that CK18 related proteins would play an important role in tumorigenesis of epithelial cancers.

Carcinoma, Hepatocellular↗