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Biomedical subjects

C W Tsai

Publications and source records attributed to C W Tsai.

At least 19 recordsLinked to original sources
PubMed2004

A double-blind comparison of the efficacy and tolerability of telmisartan 40-80 mg vs. losartan 50-100 mg in Taiwanese hypertensive patients.

A multicentre, randomised, double-blind, double-dummy, parallel-group, dose-titration study was conducted to determine the efficacy and tolerability of telmisartan 40-80 mg once daily compared with losartan 50-100 mg once daily in 180 Taiwanese patients with mild-to-moderate essential hypertension. After an initial 2-week placebo run-in phase, patients were randomised in a double-blind, double-dummy fashion to receive either telmisartan 40 mg or losartan 50 mg. If blood pressure control (diastolic blood pressure [DBP] <90 mmHg or > or = 10 mmHg reduction in DBP) was achieved after 4 weeks, the dose was maintained for the second 4 weeks of the active treatment phase; if not, the dose was doubled to telmisartan 80 mg or losartan 100 mg, respectively, for the second 4 weeks of double-blind treatment. Telmisartan 40-80 mg (n = 86) was as effective as losartan 50-100 mg (n = 90) in reducing trough seated DBP (11.1 vs. 8.7 mmHg, p = 0.144), and was significantly more effective than losartan in reducing trough seated systolic blood pressure (SBP) (22.1 vs. 16.5 mmHg, p = 0.032) and standing SBP (21.0 vs. 16.3 mmHg, p = 0.033). Significantly fewer patients treated with telmisartan than those treated with losartan required uptitration after 4 weeks' treatment (32.6% vs. 61.5%, p = 0.001). Both telmisartan and losartan were well tolerated.

Adult↗
PubMed2001

Primary structure and developmental expression of zebrafish sodium channel Na(v)1.6 during neurogenesis.

A zebrafish sodium channel cDNA encoding a 1949-amino acid polypeptide, Na(v)1.6, was isolated. Two transcripts were detected in zebrafish adult brain but not in cardiac or skeletal muscle. The RNase protection analysis confirmed the neural specificity of zebrafish Na(v)1.6 24 hours postfertilization (hpf) Na(v)1.6 was expressed in the trigeminal ganglion, anterior and posterior lateral line ganglia, rhombomeres, and Rohon-Beard neurons. This preferential localization suggests that Na(v)1.6 plays an important role in tactile sensitivity. The abundance of zebrafish Na(v) 1.6 mRNA in the central and peripheral nervous systems increased markedly between 48 and 72 hpf, during the maturation of the nervous system.

Amino Acid Sequence↗
PubMed2001

Dietary fat and garlic oil independently regulate hepatic cytochrome p(450) 2B1 and the placental form of glutathione S-transferase expression in rats.

The individual and combined effects of dietary fat and garlic oil on two drug-metabolizing enzymes, cytochrome P(450) 2B1 and the placental form of glutathione (GSH) S-transferase (PGST), in rat liver were examined in this study. Rats were fed a low corn oil, high corn oil or high fish oil diet and received various amount of garlic oil (0, 30, 80, 200 mg/kg body) orally three times per week for 6 wk. The fat energy in the low and high fat diets accounted for 11.6 and 45.7% of total energy, respectively. Final body weights did not differ among the three dietary fat groups and were not affected by garlic oil treatment. The fatty acid profile in hepatic phospholipids revealed higher eicosapentaenoic acid [20:5(n-3)] and docosahexaenoic acid [22:6(n-3)] levels in the fish oil-fed group than in the low and high corn oil-fed groups (P < 0.05). In contrast, the corn oil-fed groups had greater hepatic phospholipid arachidonic acid [20:4(n-6)] levels (P < 0.05). Both dietary fat and garlic oil significantly affected hepatic cytochrome 7-pentoxyresorufin O-dealkylase (PROD) activity and GST activity toward ethacrynic acid. Rats fed the high fish oil diet had 85 and 51% higher PROD activity compared with those fed the low or the high corn oil diet, respectively (P < 0.05). The GST activity in the high fish oil and the high corn oil groups was 33 and 18% higher than that in the low corn oil group (P < 0.05), respectively, and the GST activity in rats fed the high fish oil diet was higher than in those fed the high corn oil diet (P < 0.05). Garlic oil dose-dependently increased GST activity. No interaction between dietary fat and garlic oil on PROD or GST activity was noted. Northern and Western blot analysis revealed that dietary fish oil increased both cytochrome P(450) 2B1 and PGST mRNA and protein levels. Cytochrome P(450) 2B1 and PGST mRNA and protein levels were also dose-dependently increased by garlic oil treatment. The effects of garlic oil and dietary fat on P(450) 2B1 and PGST mRNA and protein expression were independent. These results indicate that dietary fat and garlic oil independently modulate P(450) 2B1 and PGST expression at transcriptional and/or post-transcriptional stages.

Allyl Compounds↗
PubMed2001

Cell cycle arrest allows centrin translation but not basal body formation during spermiogenesis in Marsilea.

Spermiogenesis in the water fern Marsilea vestita is a rapid process that requires the de novo formation of basal bodies in a cytoplasmic particle known as a blepharoplast. Spermiogenesis is activated by placing dry spores into water and is dependent upon the translation of new proteins from stored mRNAs with little, if any, new transcription. We looked at the necessity of cell division cycles in the gametophyte as a prerequisite for the activation of centrin translation and for the consequent formation of blepharoplasts. Cell cycle arrest was induced by treatments of gametophytes with hydroxyurea, with olomoucine, or after RNAi, employing dsRNA derived from Marsilea cyclin A or cyclin B. In all cases, centrin is translated from stored mRNA at the normal time, approximately 4 hours after imbibition, and it accumulates to maximal levels approximately 6 hours after imbibition. In spite of the fact that centrin is translated at essentially normal times and accumulates to nearly normal levels, no blepharoplasts form in the gametophytes where division cycles have been disrupted. These results provide a clear demonstration that the new translation of centrin, by itself, is insufficient for blepharoplast formation, the de novo formation of basal bodies, and the assembly of a motile apparatus.

Calcium-Binding Proteins↗
PubMed2001

Analysis of specific adaptation to a domicile habitat: a comparative study of two closely related cockroach species.

The German cockroach, Blattella germanica (L.), and the closely related species B. bisignata (Brunner) belong to the germanica species group. They are similar in appearance, life history, reproductive cycle, and courtship behavior. The most significant difference is habitat preferences: B. germanica is a household species and lives in crowded conditions, whereas the feral B. bisignata lives outdoors in a solitary manner. Nevertheless, B. bisignata has recently been found in households. A comparison between the two species has shown that B. germanica displays gregarious behavior and produces an aggregation pheromone, whereas both characters are absent in B. bisignata. Mate preference experiments have revealed that B. germanica females accepted only conspecific males, whereas B. bisignata females mated with males from both species, provided that long distance calling was bypassed. In addition, the high reproductive potential of B. germanica outcompeted the other species: when 10 pairs of B. germanica and of B. bisignata were kept together in crowded conditions during 3 mo, B. bisignata was driven into extinction. It is concluded that the chances of B. bisignata becoming a new household species are remote.

Adaptation, Physiological↗
PubMed2001

Extraction of human DNA for PCR from chewed residues of betel quid using a novel "PVP/CTAB" method.

Residues of chewed betel quid (BQ) are often found on crime scenes in Taiwan and possibly some of the Southeast Asian countries. Although these residues are important biological evidences relating to the suspects, the forensic analysis of BQ evidence has been hindered by failures in extraction of human DNA for PCR analysis. Therefore, it is a prerequisite for relevant forensic casework to establish a reliable method for extracting DNA from chewed BQ residues. Three conventional methods (salt/chloroform, 5% Chelex-100 resin, and QIAamp) were first tested for extraction of human DNA from 33 mock BQ samples, which had been stored for less than two months, and 50 four-year-old forensic BQ samples. PCR amplifications from the HLA-DQA1&PM and the STR loci were then used to test the quality of the extracted DNA. For the mock samples, three observations were made. First, PCR amplification of DNA extracted by using these conventional methods had low success rate. Second, the addition of extra Taq DNA polymerase could compensate the lost enzyme activities due to putative inhibitors and, thus, increase the yield. Third, using the Centricon-100 column to remove putative inhibitors substantially improved the efficiency of PCR. However, for the four-year-old forensic BQ samples, none of the attempts for PCR were successful. In order to solve the problem in PCR analysis of DNA from old BQ samples, we developed a DNA extraction method based on the use of polyvinyl pyrrolidone (PVP) and cetyltrimethylammonium bromide (CTAB), which bind to two common classes of PCR inhibitors in plants, polyphenols, and polysaccharides, respectively. The result showed that this "PVP/CTAB" method is completely successful for the mock BQ samples, and 92% (46 out of 50) successful for the four-year-old forensic BQ samples. To our best knowledge, this is the first report of a reliable method for the extraction of human DNA for PCR from chewed BQ residues. This method should provide a useful means for forensic identification in countries where betel chewing is common.

Areca↗
PubMed2000

A human importin-beta family protein, transportin-SR2, interacts with the phosphorylated RS domain of SR proteins.

Serine/arginine-rich proteins (SR proteins) are mainly involved in the splicing of precursor mRNA. RS domains are also found in proteins that have influence on other aspects of gene expression. Proteins that contain an RS domain are often located in the speckled domains of the nucleus. Here we show that the RS domain derived from a human papillomavirus E2 transcriptional activator can target a heterologous protein to the nucleus, as it does in many other SR proteins, but insufficient for localization in speckles. By using E2 as a bait in a yeast two-hybrid screen, we identified a human importin-beta family protein that is homologous to yeast Mtr10p and almost identical to human transportin-SR. This transportin-SR2 (TRN-SR2) protein can interact with several cellular SR proteins. More importantly, we demonstrated that TRN-SR2 can directly interact with phosphorylated, but not unphosphorylated, RS domains. Finally, an indirect immunofluoresence study revealed that a transiently expressed TRN-SR2 mutant lacking the N-terminal region becomes localized to the nucleus in a speckled pattern that coincides with the distribution of the SR protein SC35. Thus, our results likely reflect a role of TRN-SR2 in the cellular trafficking of phosphorylated SR proteins.

Amino Acid Motifs↗
PubMed2000

Chimaeric mice with disruption of the gene coding for phosphatidylinositol glycan class A (Pig-a) were defective in embryogenesis and spermatogenesis.

Mutations in the gene encoding PIG-A (phosphatidylinositol glycan class A) are found in patients with paroxysmal nocturnal haemoglobinuria (PNH), an acquired haematopoietic stem cell disorder. Individuals with hereditary PIG-A mutations have never been identified, which is also manifested by the difficulties in generating Pig-a knockout (KO) mice. This study investigated the effect of Pig-a mutations on the development of visceral and genital organs in addition to the haematopoietic system by the generation of Pig-a KO chimaeric mice. Of a total of 54 live births out of 1684 blastocysts injected, chimaerism for Pig-a knockout was detected in 29 mice, suggesting the importance of Pig-a in embryogenesis and in live birth. Quantification of the degree of chimaerism in different organs of the surviving chimaeric mice revealed extremely low levels of Pig-a KO cells in the liver and spleen. In contrast, high levels of KO signals were usually detected in the brain, heart, lung and kidney. Haematopoiesis proceeded normally in these chimaeric mice (as measured by 'complete blood cell counting') and the Pig-a KO cells were present at low levels in red blood cells and B lymphocytes but at high levels in T lymphocytes, although these KO cells did not gain any growth advantage. The effect of Pig-a knockout was also prominent in the reproductive system, another organ with high mitotic activity. Breeding the male chimaeras revealed a high rate of infertility and abnormality in the male genital organs, including abnormally shaped testes, epididymis and seminal vesicles. Even in the absence of gross abnormalities of the genital organs, low counts of motile sperm were also discernible. Pig-a KO sperm was detected in these organs; however, no transmission of the KO allele was observed. The results suggest a possible mechanism underlying the non-transmission of the Pig-a KO gene in germlines.

Animals↗
PubMed2000

Control of development and motility in the spermatozoids of lower plants.

The spermatozoids of lower plants have long been recognized as remarkably complex motile gametes. Spermatozoids differ markedly from the other gametophyte cells that surround or give rise to them. Their differentiation process involves the synthesis and assembly of a complex cytoskeleton and a motile apparatus that can be simple or complex, having as few as two to as many as thousands of ciliary axonemes. An important aspect of spermiogenesis involves the de novo synthesis of basal bodies in a cytoplasmic particle known as the blepharoplast: that is, the cells that produce spermatocytes do not contain centrioles. Thus, these cells provide an ideal system in which to study the formation of basal bodies. The cytoskeletons of spermatozoids from different organisms display a common architecture, with a multilayered structure (MLS) at the anterior end of the cell and a dorsally situated planar ribbon of crosslinked microtubules extending the length of the elongated gamete. The function of the MLS is not known, but it could be involved in cell-body elongation during development and in the control of ciliary motility in the mature gamete, particularly during chemotaxis. The application of modern techniques on these cells can shed light on long-standing problems relating to spermiogenesis and motility.

Cell Movement↗
PubMed1999

A 12-amino acid stretch in the hypervariable region of the spike protein S1 subunit is critical for cell fusion activity of mouse hepatitis virus.

The spike (S) glycoprotein of mouse hepatitis virus (MHV) plays a major role in the viral pathogenesis. It is often processed into the N-terminal S1 and the C-terminal S2 subunits that were evidently important for binding to cell receptor and inducing cell-cell fusion, respectively. As a consequence of cell-cell fusion, most of the naturally occurring infections of MHV are associated with syncytia formation. So far, only MHV-2 was identified to be fusion-negative. In this study, the S gene of MHV-2 was molecularly cloned, and the nucleotide sequence was determined. The MHV-2 S protein lacks a 12-amino acid stretch in the S1 hypervariable region from amino acid residue 446 to 457 when compared with the fusion-positive strain MHV-JHM. In addition, there are three amino acid substitutions in the S2 subunit, Tyr-1144 to Asp, Glu-1165 to Asp, and Arg-1209 to Lys. The cloned MHV-2 S protein exhibited the fusion-negative property in DBT cells as the intrinsic viral protein. Furthermore, similar to the fusion-positive MHV-JHM strain, proteolytic cleavage activity was detected both in DBT cells infected with the fusion-negative MHV-2 and in the transfected cells that expressed the cloned MHV-2 S protein. Domain swapping experiments demonstrated that the 12-amino acid stretch missing in the MHV-2 S1 subunit, but not the proteolytic cleavage site, was critical for the cell-fusion activity of MHV.

Animals↗
PubMed1999

A novel species of thermoacidophilic archaeon, Sulfolobus yangmingensis sp. nov.

A novel microbe was isolated from a geothermal vent in Yang-Ming National Park in northern Taiwan. This spherical microbe with mean cell diameter of 1.1 +/- 0.2 microns is a facultatively chemolithoautotrophic archaeon that grows on elemental sulfur and reduced sulfur compounds. The optimal pH and temperature for growth are 4.0 (pH range 2.0-6.0) and 80 degrees C (temperature range 65-95 degrees C). Its membranes contain the lipids calditoglycerocaldarchaeol and caldarchaeol, which are common to other members of the Sulfolobaceae. Like Sulfolobus acidocaldarius, Sulfolobus shibatae and Sulfolobus solfataricus, the new isolate utilizes sugars and amino acids effectively as sole carbon sources. The G + C content of the genomic DNA was 42 mol%. DNA of the isolate hybridized weakly to the DNA of other Sulfolobus species. Phylogenetic analysis of the 16S rRNA indicated that the new isolate represents a deep branch within the genus Sulfolobus. On the basis of these properties, the new isolate appears to represent a new species of Sulfolobus, for which the name Sulfolobus yangmingensis sp. nov. is proposed. The type strain is strain YM1T.

Base Composition↗
PubMed1999

D-serine added to clozapine for the treatment of schizophrenia.

OBJECTIVE: D-Serine is a full agonist at the glycine site on the N-methyl-D-aspartate (NMDA) receptor. Previous administration of D-serine to schizophrenic patients taking nonclozapine antipsychotics improved positive, negative, and cognitive symptoms, whereas the partial agonist D-cycloserine improved negative symptoms of patients taking conventional antipsychotics but worsened symptoms in clozapine-treated patients. To study the difference between full and partial agonists at the NMDA receptor glycine site, the clinical effects of adding D-serine to clozapine were assessed. METHOD: In a 6-week double-blind trial, 20 schizophrenic patients received placebo or D-serine (30 mg/kg per day) in addition to clozapine. Clinical efficacy, side effects, and serum levels of D-serine were determined every other week. RESULTS: The patients exhibited no improvement with D-serine, nor did their symptoms worsen, as previously reported with D-cycloserine. CONCLUSIONS: The results suggest either that clozapine may have an agonistic effect on the NMDA system or that clozapine-treated patients do not respond to D-serine.

Antipsychotic Agents↗
PubMed1997

Pyogenic myositis: caused by viridans streptococci in an adult with tetralogy of Fallot.

A 34-year-old man came to this Emergency Room because of fever, swelling and pain in the right thigh. Tetralogy of Fallot with bicuspid pulmonary valve was diagnosed after serial examination, and computed tomography of the right thigh revealed pyogenic myositis. Surgical drainage of the right thigh abscess and a further pus culture yielded viridans streptococci. There has been no record in the medical literature of a pyogenic myositis caused by viridans streptococci in an adult tetralogy of Fallot. This is thus the first case reported.

Adult↗
PubMed1996

Thrombophilia in patients with hypercholesterolemia.

To investigate a possible interrelationship between hypercholesterolemia and the coagulation and fibrinolytic system, the Cardiovascular Disease Risk Factor Two-Township Study in Taiwan was undertaken as a longitudinal prospective study focusing on the evolution of cardiovascular disease risk factors, with an emphasis on hemostatic factors. Hemostatic parameters measured in this study included prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen, factor VIIc, factor VIIIc, antithrombin III, and plasminogen. Subjects of both sexes with hypercholesterolemia (> 6.2 mmol/L) also had significant elevations of diastolic blood pressure, plasma glucose, triglycerides, fibrinogen, and factor VIIc and reduced PT and APTT compared with subjects with lower cholesterol. The hypercholesterolemic women additionally had significant elevations of systolic blood pressure and factor VIIc. Levels of the anticoagulant factors, antithrombin III and plasminogen, were also higher in both hypercholesterolemic men and women. In men, only factor VIIIc had no statistically significant elevation. In women, only PT showed no statistical difference. Established coronary risk factors such as fibrinogen and factor VIIc showed remarkable elevations in patients of both sexes. Using Pearson correlation and multiple regression, the most significant parameter related to cholesterol level was factor VIIc. The present results show that hemostatic abnormalities do exist in patients with hypercholesterolemia, and this thrombophilic phenomenon sheds further light on the study of higher cardiovascular mortality in these subjects.

Blood Pressure↗
PubMed1996

Squamous cell carcinoma of the nail bed.

Squamous cell carcinoma of the nail bed is a rare disorder. Metastasis is extremely unusual. A case of primary squamous cell carcinoma of the nail bed with metastasis to the regional lymph nodes is reported. The tumor was successfully treated by amputation of the involved finger, block dissection of the regional lymph nodes, postoperative irradiation of the involved axilla, and systemic chemotherapy. Early diagnosis by biopsy, especially in patients with recurrent and persistent disease of the nail bed, is recommended, so that treatment can be instituted early while the tumor is confined to its primary site.

Adult↗
PubMed1996

Transcatheter embolization of a coronary arteriovenous fistula with a complex, helical-fibered platinum coil.

Transcatheter embolization was successfully performed on a 51-year-old man with a coronary arteriovenous fistula arising from the left circumflex coronary artery and draining into the superior vena cava. The patient presented with typical manifestations of angina pectoris that were first noticed during childhood but had worsened over the past 5 years. A 2 x 20 mm complex, helical-fibered platinum coil was placed in the mid-portion of the fistula and successfully occluded the fistula within 30 minutes. The patient has been free from angina pectoris since the procedure.

Arteriovenous Fistula↗
PubMed1995

Increased sympathetic nervous system activity in Chinese hypertensive patients with type II diabetes mellitus.

To evaluate the coexistence of sympathetic overactivity and hypertension in type 2 diabetic patients, a population-based study was conducted of newly-diagnosed type 2 diabetic patients recruited from a single community located at northern Taiwan. This study included 2877 (male 1382, female 1495) middle-aged ethnic Chinese adults, aged 45-65 years. Of the 1382 males, 67 had newly-diagnosed type 2 diabetes mellitus, whereas 75 of the 1495 females had type 2 diabetes. The data showed that about 39% of diabetic patients had borderline hypertension (mean blood pressure 141/91 mmHg) whereas the average incidence in non-diabetic subjects was 15.5%. The borderline hypertensive diabetic patients had significantly higher heart rates (mean 78.8 vs. 69.3 beats/min; P < 0.001) than control subjects. However, the cardiac index was similar in both control and diabetic subjects (mean 2.48 vs. 2.53 l/min/m2; P > 0.05). Our data show that sympathetic overactivity and increased incidence of hypertension actually existed in these type 2 diabetic patients of Chinese origin.

Analysis of Variance↗