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Biomedical subjects

C T Hsu

Publications and source records attributed to C T Hsu.

At least 19 recordsLinked to original sources

Role of hypothalamic neuropeptide Y (NPY) in the change of feeding behavior induced by repeated treatment of amphetamine.

Neuropeptide Y (NPY), an orexigenic peptide, is involved in the control of food intake. Repeated administration of amphetamine (AMPH), an anorectic agent, results in an anorectic effect on day 1 and a tolerant anorectic effect on the followings. In an attempt to know the role of hypothalamic NPY in these effects of AMPH, contents of hypothalamic NPY were determined by radioimmunoassay at first. In AMPH-treated groups, the contents of hypothalamic NPY decreased rapidly on day 1 but restored gradually to the normal level on the following days as observed in repeated AMPH. An involvement of hypothalamic NPY in the feeding change of repeated AMPH can thus be considered. Moreover, daily injection of NPY antisense oligonucleotide into brain (10 microg/10 microl/day, i.c.v.) to inhibit the gene expression of hypothalamic NPY were performed at 1 hour before daily 2 mg/kg AMPH. The reversion of food intake from the anorectic level to the normal level (tolerant anorexia) was abolished by this antisense pretreatment. It is suggested that hypothalamic NPY may play a role in the change of feeding behavior induced by repeated AMPH administration.

Amphetamine↗

Endoscopic comparison of the gastroduodenal safety and the effects on arachidonic acid products between meloxicam and piroxicam in the treatment of osteoarthritis.

Our objective was to evaluate the efficacy, the gastroduodenal safety, and the effects on arachidonic acid products of meloxicam, a new acidic enolic non-steroidal anti-inflammatory drug which preferentially inhibits cyclo-oxygenase-2 over cyclo-oxygenase-1, versus piroxicam in patients with osteoarthritis of the knee. Meloxicam 7.5 mg or piroxicam 20 mg daily was administered for 4 weeks in this double-blind parallel-groups randomised study. The efficacy for pain relief of the two tested medications was assessed by means of visual analogue scale and other clinical parameters. Pre- and post-treatment endoscopies were performed, and the findings were scored and recorded. The gastric fluid was aspirated at each time and prostaglandin E2, thromboxane B2 and leukotriene B4 were determined by ELISA. There was no significant difference between the groups regarding the primary efficacy. Changes in endoscopic findings by means of Lanza score showed statistically significant differences between the two treatment groups in favour of meloxicam at all sites--gastric, duodenal and total. Within-group comparisons showed a statistically significant difference (worsening) in gastric and total score with piroxicam, but no significant difference with meloxicam. The frequency of clinically relevant cases (total score >2) also showed a statistically significant worsening in the piroxicam group. The better GI tolerability of meloxicam was also suggested by fewer adverse GI events and no withdrawals due to adverse events compared with piroxicam. The pre-/post-study gastric juice concentration of PGE2, TXB2, and LTB4 in the meloxicam group was 135.2 +/- 85.8/71.2 +/- 32.2, 116.3 +/- 81.7/99.4 +/- 107.5 and 388 +/- 321/223 +/- 98 pg/ml respectively. The pre-/post-study gastric juice concentration of PGE2, TXB2 and LTB4 in the piroxicam group was 105.7 +/- 43.1/68.2 +/- 34.9, 94.0 +/- 50.9/105.9 +/- 121.1 and 625 +/- 1574/828 +/- 1464 pg/ml, respectively. Both meloxicam and piroxicam significantly inhibited gastric PGE2 levels after 4 weeks' treatment; however, there was no difference between these two groups. Neither of these medications had an effect on TXB2. Only meloxicam inhibited LTB4 concentration significantly, and the between-groups difference was significant. Meloxicam 7.5 mg once daily had better gastrointestinal tolerability and an efficacy comparable to that of piroxicam 20 mg over 4 weeks in patients with osteoarthritis of the knee.

Adult↗

The sympathetic nervous system promotes carbon tetrachloride-induced liver cirrhosis in rats by suppressing apoptosis and enhancing the growth kinetics of regenerating hepatocytes.

Norepinephrine is considered to possess potent anti-apoptotic action in regenerating hepatocytes. To clarify the role of the sympathetic nervous system in apoptosis that occurs in chronic liver damage and following the promotion of liver cirrhosis, we studied a carbon tetrachloride (CCl4)-induced liver injury model, using spontaneously hypertensive rats (SHR), Wistar-Kyoto rats (WKY), and chemically sympathectomized WKY. At 24 h after CCl4 administration. acute damage, characterized by vacuolated hepatocytes in the centrilobular zone, was greater in SHR than in WKY. This vacuolated change in WKY hepatocytes was significantly reduced by chemical sympathectomy with 6-hydroxydopamine (6-OHDA). After 48 h, the acute damage was dramatically improved in each animal, without significant differences between the three groups. In chronic damage after weekly repetition of CCl4 treatment for 4 weeks, fibrosis was evident in SHR, while in the other groups there was only scant fibrosis in the centrilobular zone. After 8 weeks' repetition of CCl4, liver cirrhosis was seen only in SHR. The incidence of apoptotic cells in areas of both acute and chronic damage in WKY, detected by terminal deoxynucleotidyl transferase-dUTP nick end labeling, was significantly increased in comparison with that in SHR, and was further increased by 6-OHDA pretreatment. In contrast, there was significantly greater enhancement of the growth of hepatocytes in SHR than in WKY in both acute and chronic damage. Moreover. hepatocyte growth kinetics in WKY was significantly inhibited after sympathectomy in acute injury, as evidenced by immunohistochemistry for proliferating cell nuclear antigen (PCNA). In vitro, the amount of hepatocellular apoptosis induced by transforming growth factor-beta1 was significantly decreased by incubation with norepinephrine. These findings suggest that the anti-apoptotic effect of the sympathetic nervous system increases cell growth kinetics and promotes liver cirrhosis in this animal model.

Animals↗

Prognostic value of nm23 expression in stage IB1 cervical carcinoma.

BACKGROUND: The purpose of this retrospective study was to evaluate the patterns of nm23 expression in stage IB1 squamous cell carcinoma of the uterine cervix, to compare nm23 expression with clinicopathological findings and to assess its prognostic value. METHODS: Twenty-seven patients with stage IB1 squamous cell carcinoma of the uterine cervix underwent abdominal radical hysterectomy and pelvic lymph node dissection. Expression of nm23 was studied immunohistochemically, followed by amplification and direct sequencing of exons 4 and 5 of the nm23 gene. RESULTS: Overexpression of nm23 was detected in 18.5% of the tumors and low expression was seen in 33.3%, while negative expression was found in 48.1% of the tumors. Deep cervical stromal invasion (> or =1/2) was found to be associated with the increased risk of lymph node metastases (odds ratio = 17.5). A significantly lower percentage of patients survived when nm23 overexpression was observed (p = 0.0063). Univariate analysis revealed that tumor size (2-3.9 cm), lymph node metastasis, tumor invasion into parametria, tumor invasion into blood/lymph vessel, squamous cell carcinoma (> or =2 ng/ml) and nm23 overexpression had a significantly lower recurrence-free survival rate of the patients. None of the above factors was significant according to multivariate analysis. There were no mutations in exons 4 and 5 of the nm23 gene in stage IB1 squamous cell carcinoma of the uterine cervix. CONCLUSIONS: This study suggests that expression of nm23 may be indicative of an unfavorable prognosis in patients with stage IB1 squamous cell carcinoma of the uterine cervix.

Adult↗

Choroidal infarction, anterior ischemic optic neuropathy, and central retinal artery occlusion from polyarteritis nodosa.

PURPOSE: Ocular ischemia from polyarteritis nodosa (PAN) is rare. The authors present a case of multifocal ocular infarction from PAN. METHODS AND RESULTS: A 70-year-old woman developed hand and foot numbness followed by intermittent blurred vision and binocular horizontal diplopia. Two weeks later, she suddenly lost vision in the right eye from a central retinal artery occlusion and then developed a left anterior ischemic optic neuropathy and bilateral triangular choroidal abnormalities consistent with infarction. Her erythrocyte sedimentation rate and C-reactive protein were elevated. Although giant cell arteritis was suspected, a multiple mononeuropathy was demonstrated by electromyogram and nerve conduction velocity studies. Biopsy specimens from her sural nerve and biceps muscle showed a necrotizing vasculitis with fibrinoid necrosis, consistent with PAN. CONCLUSIONS: Polyarteritis nodosa can produce ischemia of a variety of ocular structures, including the retina, choroid, and optic nerve. In our patient, all three structures were affected. To our knowledge, this is the first reported case of the triangular sign of Amalric in PAN.

Aged↗

Vaccination against gonadotropin-releasing hormone (GnRH) using toxin receptor-binding domain-conjugated GnRH repeats.

A method for the preparation of an immunogen containing multiple copies of a self-peptide in linear alignment was designed in order to overcome the difficulty of inducing an immune response to poorly immunogenic peptide antigens. DNA fragments encoding multiple repeats of the self-peptide were generated by a new technique, termed template-repeated polymerase chain reaction (TR-PCR), which could be subcloned into an expression vector for production of peptide repeats as an immunogen. This approach was tested by constructing fusion proteins containing the receptor-binding domain of Pseudomonas exotoxin A and multiple copies of the 10-residue sequence of the peptide hormone gonadotropin-releasing hormone (GnRH). Immunization of female rabbits with the immunogen that contained the exotoxin receptor-binding domain and 12 copies of GnRH (PEIa-GnRH12) resulted in the generation of high-titer antibodies specific for GnRH. Although at equal molar basis of the GnRH moiety, the immunogen that contained single copy of GnRH (PEIa-GnRH1) induced low-titer anti-GnRH antibodies. These observations suggest that the presence of multiple peptide repeats is a key factor in eliciting an immune response. In addition, anti-GnRH antibodies effectively neutralized GnRH activity in vivo, as demonstrated by the degeneration of the ovaries in the injected rabbits. Because anti-GnRH antibody could be functionally analogous to GnRH antagonist, which has been used to treat patients with ovarian cancer, vaccination of PEIa-GnRH12 presents a potential therapeutic application for the treatment of GnRH-sensitive ovarian cancer.

ADP Ribose Transferases↗

Bcl-2 accelerates retinoic acid-induced growth arrest and recovery in human gastric cancer cells.

The role of Bcl-2 as an anti-apoptotic protein has been well documented. In the present work, we present evidence that Bcl-2 may also be involved in cell growth regulation. SC-M1 is an unique cell line which responds to retinoic acid (RA) treatment with reversible growth arrest [Shyu, Jiang, Huang, Chang, Wu, Roffler and Yeh (1995) Eur. J. Cancer 31, 237-243]. In this study, when treated with RA, SC-M1/Bcl2 cells, which were generated by transfecting SC-M1 cells with bcl-2 DNA, were growth-arrested two days earlier than SC-M1/neo cells, which were generated by transfecting SC-M1 cells with vector DNA. This indicates that Bcl-2 accelerates RA-induced growth arrest. In addition to the accelerated growth arrest, RA-treated SC-M1/Bcl2 cells also recovered from growth arrest two days faster than SC-M1/neo cells after the removal of RA. Previously, we had identified the cyclin-dependent kinase inhibitor p21((WAF1/CIP1)) (p21) as a mediator of RA-induced growth arrest [Tsao, Li, Kuo, Liu and Chen (1996) Biochem. J. 317, 707-711]. In a search for the mechanism by which Bcl-2 affects growth regulation, we found that p21 gene expression was more prominent in SC-M1/Bcl2 cells than in SC-M1/neo cells in the presence of RA, but when RA was removed, p21 gene expression levels in SC-M1/Bcl2 cells were also reduced earlier than in SC-M1/neo cells. The present report is the first to show that Bcl-2 accelerates not only growth arrest but also recovery from growth arrest. Moreover, the close correlation between the effect of Bcl-2 on both RA-induced growth arrest and RA-induced p21 gene expression suggests the possibility that Bcl-2 affects cell growth through the mechanism of p21.

Cell Cycle↗

Development of DNA delivery system using Pseudomonas exotoxin A and a DNA binding region of human DNA topoisomerase I.

Gene therapy is defined as the delivery of a functional gene for expression in somatic tissues with the intent to cure a disease. Thus, highly efficient gene transfer is essential for gene therapy. Receptor-mediated gene delivery can offer high efficiency in gene transfer, but several technical difficulties need to be solved. In this study, we first examined the DNA binding regions of the human DNA topoisomerase I (Topo I), using agarose gel mobility shift assay, in order to identify sites of noncovalent binding of human DNA Topo I to plasmid DNA. We identified four DNA binding regions in human DNA Topo I. They resided in aa 51-200, 271-375, 422-596, and 651-696 of the human DNA Topo I. We then used one of the four regions as a DNA binding protein fragment in the construction of a DNA delivery vehicle. Based on the known functional property of each Pseudomonas exotoxin A (PE) domain and human DNA Topo I, we fused the receptor binding and membrane translocation domains of PE with a highly positively charged DNA binding region of the N-terminal 198 amino acid residues of human DNA Topo I. The resulting recombinant protein was examined for DNA binding in vitro and transfer efficiency in cultured cells. The results show that this DNA delivery protein is a general DNA delivery vehicle without DNA sequence, topology, and cell-type specificity. The DNA delivery protein could be used to target genes of interest into cells for genetic and biochemical studies. Therefore, this technique can potentially be applied to cancer gene therapy.

ADP Ribose Transferases↗

Prognostic value of p53 expression in stage IB1 cervical carcinoma.

The purpose of this retrospective study was to evaluate the patterns of p53 expression in stage IB1 squamous cell carcinoma of the uterine cervix, to compare p53 expression with clinicopathological findings, and to assess its prognostic value. 27 patients with stage IB1 squamous cell carcinoma of the uterine cervix underwent abdominal radical hysterectomy and pelvic lymph node dissection. Expression of p53 was studied immunohistochemically. Overexpression of p53 was detected in 33.3% of the tumors, low expression was seen in 11.1%, and negative expression was found in 55.6%. Deep cervical stromal invasion (> or = 1/2) was found to be associated with the increased risk of lymph node metastases (odds ratio = 17.5). A significantly lower percentage of patients survived when p53 overexpression was observed (p = 0.0315). Univariate analysis revealed that tumor size (2-3.9 cm), lymph node metastasis, tumor invasion into parametria, tumor invasion into blood/lymph vessels, squamous cell carcinoma antigen (> or = 2 ng/ml), and p53 overexpression had a significantly lower recurrence-free survival rate. None of these above factors obtained significance in the multivariate analysis. This study suggests that expression of p53 may be indicative of an unfavorable prognosis in patients with stage IB1 squamous cell carcinoma of the uterine cervix.

Adult↗

Tumor seeding of the jejunostomy site after transhiatal esophagectomy for esophageal carcinoma.

A 65-year-old male patient with squamous cell carcinoma of the esophagus had a transhiatal esophagectomy after a prophylactic tube jejunostomy. The tube was removed 3 weeks after surgery. Ten months later, a painless 2-cm abdominal mass was noted at the previous jejunostomy site. Subsequent segmental resection of the jejunum disclosed metastatic squamous cell carcinoma of the esophagus. It is possible that tumor seeding may develop at the jejunostomy site after transhiatal esophagectomy for esophageal carcinoma.

Aged↗

Educational puzzles for understanding gastrointestinal physiology.

We developed four innovative, creative, and fun educational tools to promote active learning, enhance problem-solving skills, and encourage small group discussion. Furthermore, the tools encourage deductive reasoning and critical thinking rather than passive memorization of material. The tools include crossword puzzles, hidden messages, word scrambles, and word searches. These tools were developed using two computer programs: the Crossword Construction Kit and The New Puzzle Factory. Instructors are encouraged to optimize the value of the tools by using the additional options presented at the end of each of the puzzles. The additional options encourage students to become active learners by creating their own tools. Although the principles of these four tools can be adapted to many disciplines, these specific games focused on gastrointestinal physiology. Our goal was to create tools that can be used either inside or outside the classroom to complement and enhance the lecture.

Education, Medical, Undergraduate↗

"Virtual rat": a tool for understanding hormonal regulation of gastrointestinal function.

This manuscript describes a "dry laboratory" using the "virtual rat" to help students understand the hormonal regulation of gastrointestinal function. The laboratory was modeled after a recent exercise that used the virtual rat to teach basic endocrine physiology. The virtual rat concept avoids the many obstacles associated with animal experimentation (for example, lack of adequate animal facilities, expense, equipment, and limited teacher experience). Our goal was to create a fun and educational experience while avoiding the complications associated with laboratory experimentation. No additional materials are required to complete this exercise. After finishing this laboratory, the students should have a greater understanding and appreciation for experimental design and the collection, analysis, and interpretation of data.

Animals↗

A multicenter study on eradication of Helicobacter pylori infection in patients with duodenal ulcer by lansoprazole-antibiotics combined therapy.

The aim of this prospective randomized multicenter study was to find out if there is one or several promising regimens containing lansoprazole with various combinations of antibiotics which have a high eradication rate of Helicobacter pylori, few side-effects, good patient compliance, and relative low cost if possible. Two hundred and ninety-seven patients with H. pylori positive duodenal ulcer were enrolled and randomly allocated into one of the five treatment groups: 1) group A: received lansoprazole 30 mg once daily for 2 weeks plus amoxicillin (AM) 500 mg and metronidazole (MZ) 500 mg twice daily for one week in the first week; 2) group B: the AM in group A was replaced by clarithromycin (CM) 250 mg; 3) group C: the MZ in group A was replaced by CM 250 mg; 4) group D: the AM and CM in group C was used for 2 wk; 5) group E: the CM in group D was doubled to 500 mg twice daily. All patients received endoscopies pre- and 4-6 weeks post termination of treatment. H. pylori was detected by culture, histology and rapid urease test (CLO test). 13C-urea breath test was performed if the patients refused the second endoscopy. The E-test was adopted to evaluate the MZ and CM resistance of H. pylori. Totally, 253 patients completed the study. The eradication rate of groups A, B, C, D and E were 75%, 80%, 78%, 92%, and 96%, respectively. The eradication rate of group E was significantly higher than that of groups A, B, or C. There were no significant differences of eradication rates between the groups D and E. Sixty-seven cases (28.8%) were MZ-resistant. The difference of eradication rates between MZ-S and MZ-R patients was significant in group A (85.3% vs. 42.9%) and in the combination of groups A and B (83.8% vs. 59.4%). Good compliance (defined as taking > 90% of medications) was seen in more than 90% of cases in each group. Triple therapy containing lansoprazole 30 mg once daily, AM 500 mg and CM 250 mg twice daily for two weeks is a promising regimen which reaches a high eradication rate, avoids MZ resistance, and has very good patient compliance at an acceptable cost.

2-Pyridinylmethylsulfinylbenzimidazoles↗

Superoxide dismutase gene expression and activity in the brain of spontaneously hypertensive rats and normotensive rats.

OBJECTIVE: To determine if changes in superoxide dismutase (SOD) in the brain occur in the hypertensive state. METHODS: We compared the levels of the two main subtypes of this enzyme in spontaneously hypertensive rats (SHR) with age-matched normotensive Wistar Kyoto (WKY) rats using enzyme activity estimation, Western blotting for enzyme contents, and Northern blotting of mRNA level. Five discrete brain regions, cerebrocortex, hypothalamus, hippocampus, the remaining non-cortex cerebrum (NCC area), and cerebellum, were employed for comparison in 30-31 weeks old rats. RESULTS: A lower level of both Mn-SOD activity and Mn-SOD mRNA expression was found in all areas of the brain of SHR as compared with WKY rats. Also, the mRNA levels of Cu, Zn-SOD in the brain of SHR differed from WKY rats in parallel to the enzyme activities. The activity and mRNA expression of Cu, Zn-SOD were lower in the hypothalamus and cerebellum of SHR but the mRNA level and the activity in hippocampus were significantly higher in the SHR compared to WKY rats. No differences for Cu, Zn-SOD were observed in cerebrocortex or NCC area in the two species. However, the amount of SOD enzyme subtypes, determined by Western blotting analysis, was not different between SHR and WKY rats. CONCLUSIONS: The results indicate a lower gene expression and less activity of Mn-SOD in SHR brain. This alternation of SOD may be one of the important factors for the vulnerability of the brain from oxygen free radicals or may be related to the pathogenesis of hypertension in this species.

Animals↗

Activation of beta3-adrenoceptors by exogenous dopamine to lower glucose uptake into rat adipocytes.

The effect of dopamine hydrochloride on beta3-adrenoceptors was studied in isolated adipocytes of Wistar rats using uptake of [14C]-deoxy-D-glucose (2-DG) as the indicator. Dopamine induced a concentration-dependent decrease of 2-DG uptake into adipocytes in a manner which was not modified by haloperidol at concentrations sufficient to block dopaminergic receptors. Failure of blockade was also observed in samples receiving the pretreatment with a mixture of SCH23390 and domperidone, the dopaminergic antagonists. Absence of dopaminergic receptors in rat white adipocytes was further supported by the findings that dopaminergic agonists did not modify the glucose uptake and the negative response to receptor antibodies in immunoblotting analysis. Pindolol and propranolol reversed this inhibition of dopamine in a concentration-dependent manner. However, this action of dopamine was not affected by prazosin at concentrations sufficient to block alpha-adrenoceptors. Effect of dopamine was reduced in the presence of Rp-cyclic AMPS triethylamine, the membrane-permeable antagonist of cyclic AMP (cAMP), indicating the mediation of cAMP in this inhibition. Direct effect of exogenous dopamine on beta3-adrenoceptors was identified using the antibody for beta3-adrenoceptors that reversed the inhibition of dopamine. These results suggest that dopamine can activate beta3-adrenoceptors to lower glucose uptake into rat white adipocytes which lack dopaminergic receptors.

Adipocytes↗

Ultrastructural changes in liver damage induced by carbon tetrachloride in spontaneously hypertensive rats and Wistar-Kyoto rats.

The effects of carbon tetrachloride (CCl4) on the liver in spontaneously hypertensive rat (SHR) and Wistar-Kyoto rat (WKY) were investigated ultrastructurally in this study. Repetition of CCl4 treatment twice a week for four weeks, revealed liver cirrhosis in SHR, whereas, only bridging fibrosis was observed in the WKY, histologically, by reticulin silver impregnation. Scanning electron microscopy revealed that the liver surface of SHR was irregularly nodulated, while it was relatively smooth in case of the WKY. Transmission electron microscopy revealed that the mitochondria cristae were peripherally located in both strains. Vesicular change of the rough endoplasmic reticulum was observed to be more severe in SHR than in WKY. Further, local hypertrophy of the smooth endoplasmic reticulum and large lipid droplets were more easily observed in WKY than in SHR. The present results hence indicate that chronic chemical CCl4 intoxication induces severe ultrastructural organelle damage in hypertensive rats, leading to liver cirrhosis. On the other hand, CCl4 induced fatty liver and a relatively mild fibrosis were observed in normotensive rats. These findings suggest that the liver ultrastructural organelles are more susceptible to CCl4 in SHR than in WKY.

Animals↗

Stimulatory effect of octopamine on beta 3-adrenoceptors to lower the uptake of [14C]-deoxy-D-glucose into rat adipocytes in vitro.

1. The effect of octopamine on beta 3-adrenoceptors has been studied in isolated adipocytes of Wistar rats using uptake of [14C]-deoxy-D-glucose as the indicator. 2. Octopamine (0.1-1 nmol 1-1) induced a concentration-dependent decrease of [14C]-deoxy-D-glucose uptake into the adipocytes and this inhibition was not influenced by haloperidol at concentrations sufficient to block dopaminergic receptors. 3. Pindolol and propranolol reversed this inhibition of octopamine in a concentration-dependent manner. The effect of octopamine was reduced in the presence of Rp-cyclic AMPS triethylamine, the membrane-permeable antagonist of cyclic AMP (cAMP), indicating the mediation of cAMP in this inhibition. 4. A direct effect of octopamine on beta 3-adrenoceptors was proved using the application of antibodies. In the presence of an antibody for beta 3-adrenoceptors, the actions of octopamine were concentration-dependently reduced in a manner similar to the decrease of BRL37344-induced inhibitions. 5. The same degree of diminished activities for octopamine as that of BRL37344, the well-known specific agonist of beta 3-adrenoceptors, was also obtained in isoprenline-desensitized adipocytes. Insulin-stimulated uptake of [14C]-deoxy-D-glucose into adipocytes was not modified by isoprenaline induced desensitization. 6. These results suggest that octopamine can activate beta 3-adrenoceptors to lower the glucose uptake through an increase of cAMP in rat white adipocytes.

Adipocytes↗