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R Tang

Publications and source records attributed to R Tang.

At least 109 records · Page 6Linked to original sources
PubMed1996

The alpha-adrenoceptor antagonist properties of the enantiomers of doxazosin in the human prostate.

The alpha-adrenoceptor antagonist properties of doxazosin and its enantiomers were characterized using human prostate tissue and cell membranes isolated from rat-1 fibroblast expressing each of the cloned human alpha 1-adrenoceptor subtypes. In the alpha 1-adrenoceptor-binding studies on the human prostate with [3H]doxazosin and 2-{[beta-(3-[125I],4-hydroxyphenyl)ethyl]aminomethyl}-l-tetralone ([125I]HEAT), no significant differences were observed between racemic doxazosin, R-doxazosin and S-doxazosin (mean -log Ki (pKi) values were 8.60-8.63, 8.47-8.55 and 8.61-8.65, respectively), whereas the alpha 2-adrenoceptor-binding studies with [3H]rauwolscine and [3H]clonidine revealed that the alpha 2-adrenoceptor-binding affinity of S-doxazosin (pKi = 5.91-5.94) was slightly (3- or 4-fold), but significantly lower than that of R-doxazosin (pKi = 6.47-6.54). Studies in phenylephrine-contracted prostatic tissue showed no significant difference in alpha 1-adrenoceptor antagonist potency between racemic doxazosin, R-doxazosin and S-doxazosin (pA2 values were 8.43 +/- 0.28, 8.64 +/- 0.56 and 8.75 +/- 0.38, respectively). In the binding studies with cloned alpha 1-adrenoceptor subtypes using [3H]prazosin and [125I]HEAT, racemic doxazosin, R-doxazosin and S-doxazosin showed no selectivity for the alpha 1-adrenoceptor subtypes. The present study demonstrated that doxazosin and its enantiomers are highly selective alpha 1-adrenoceptor antagonists and that there is no evidence suggesting differential alpha 1-adrenoceptor antagonist effects of doxazosin and its enantiomers in the human prostate. Doxazosin, therefore, could be described as displaying balanced activity across all three alpha 1-adrenoceptor subtypes.

Adrenergic alpha-Antagonists↗
PubMed1996

Hemorrhoidectomy with self-retaining retraction.

Hemorrhoidectomy is one of the most effective treatments for significantly symptomatic hemorrhoids. By placing the patient in the Sims' position and appropriately using the Hill-Ferguson retractor and towel clip, the surgeon can get good exposure and perform a Ferguson closed hemorrhoidectomy without any assistance.

Hemorrhoids↗
PubMed1996

2-(methylamino)-5-chlorobenzophenone imine: a novel product formed in base-catalyzed hydrolysis of diazepam.

Diazepam (1), a hypnotic and anxiolytic drug in worldwide use, formed an intermediate product in a mixture of ethanol and sodium hydroxide ([NaOH] > or = 1 M). The intermediate product slowly decomposed to form 2-(methylamino)-5-chlorobenzophenone imine (2) and 2-(methylamino)-5-chlorobenzophenone (3). The amount of 2 formed, relative to that of 3, increased with increasing NaOH concentration. Compound 2, a heretofore unknown derivative of 1, was characterized by high-performance liquid chromatography, ultraviolet-visible absorption, mass, and proton nuclear magnetic resonance spectral analyses.

Benzophenones↗
PubMed1996

Expression of the multidrug resistance-associated protein (MRP) mRNA and protein in normal peripheral blood and bone marrow haemopoietic cells.

We studied the expression of multidrug resistance-associated protein (MRP) in normal haemopoietic cells from peripheral blood and bone marrow. The MRP mRNA levels were estimated by RT/PCR and in situ hybridization (ISH) assay, and the protein levels by flow cytometry. 21 samples of peripheral blood and 21 samples of bone marrow (11 normal bone marrow donors, 10 patients in complete remission after chemotherapy for large cell lymphoma or acute myeloid leukaemia) were analysed. In peripheral blood the mean MRP mRNA level in CD3+ cells was statistically higher than in the other cells (3-fold by the methods used). The levels of MRP in CD3+ varied from one individual to another (4.5-34.8 units by RT/PCR and 5-23 grains/cell by ISH); however, this was proportional to the variation in all the cell lineages of same individual (r = 0.84). In bone marrow the mean MRP levels of the various cell lineages (including CD34+) were similar to the basal level in HL60 cells. Individual expression levels were again variable; however, there was no difference between untreated normal bone marrow and post chemotherapy normal bone marrow. MRP protein expression was determined by flow cytometry with the monoclonal antibody MRPm6. The CD4+ lymphocytes exhibited a higher MRP protein expression than the other cell lineages, including CD8+ cells. There was a good correlation between the three methods used (RT/PCR and ISH, P = 0.0001, r = 0.87; RT/PCR and flow cytometry, P = 0.0001, r = 0.85; ISH and flow cytometry, P = 0.002, r = 0.67).

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

Cellular growth state differentially regulates enterocyte gene expression in butyrate-treated HT-29 cells.

Enterocyte differentiation occurs at the crypt-villus junction through the transcriptional activation of cell-specific genes, including the brush-border enzyme intestinal alkaline phosphatase (IAP) and the microvillar structural protein, villin. Based upon previous in vivo studies demonstrating that IAP and villin are differentially affected by alterations in epithelial growth state, we examined the regulation of these two genes in an in vitro model of enterocyte differentiation. HT-29 cells were maintained in DMEM + 10% FCS and treated with sodium butyrate to induce enterocyte differentiation. Cell count and [3H]thymidine measurements confirm that sodium butyrate causes a marked decrease in cellular growth state, consistent with the differentiation process. Northern blot analyses revealed time- and dose-dependent increases (P < 0.001) in steady-state IAP and villin mRNA levels. The increases in both IAP and villin expression were dependent upon the presence of one or more newly synthesized proteins. Post-confluence and serum starvation were used to cause cell cycle withdrawal prior to the differentiation process. As predicted from our previous in vivo data, villin expression was unaffected by changes in cellular growth state, whereas IAP expression was dramatically diminished under hypoproliferative conditions. We conclude that early withdrawal from the cell cycle alters the course of enterocyte differentiation, specifically decreasing IAP expression.

Alkaline Phosphatase↗
PubMed1996

Ultrasound protocol and quality control procedures in the European Lacidipine Study on Atherosclerosis (ELSA).

The European Lacidipine Study on Atherosclerosis (ELSA) is a multinational interventional clinical trial aimed at determining the antiatherosclerotic effects of Lacidipine, a calcium antagonist, when compared to atenolol, a beta-blocker, on the carotid arteries of 2300 cardiovascular asymptomatic patients with moderately high blood pressure. Quantitative B-mode ultrasound imaging is being used to measure the intima-media thickness of a standardized section of the carotid arteries including the distal common, bifurcation, and proximal internal carotids. Prospective investigations of large samples of population using ultrasonographic endpoints rely heavily on the precision and reproducibility of the method. Therefore, specific quality control protocols are required to determine and monitor cross-sectional and longitudinal stability of the measurement reproducibility. In ELSA, the ultrasound methodology was specifically designed to include a set of procedures to quality control the critical components of measurement variation including instrumentation, and ultrasound operators, i.e. sonographers and readers. The ELSA clinical trial will provide the largest set of prospective quality control data on the use of quantitative B-mode ultrasound imaging.

Arteriosclerosis↗
PubMed1995

Prognostic evaluation of DNA flow cytometric and histopathologic parameters of colorectal cancer.

BACKGROUND: The clinical value of DNA flow cytometry of colorectal cancer is unclear. The purpose of this retrospective study was to evaluate the relationship between tumor flow cytometry, histopathologic parameters, and survival. METHODS: Flow cytometry was performed on paraffin embedded specimens from 653 patients who had surgery from 1980 to 1983. RESULTS: Aneuploidy was associated with distal tumor, perineural invasion, desmoplastic reaction, and failure to secrete mucin. TNM Stage I tumors were more frequently diploid than were more advanced tumors (71% vs. 41%). An abnormal DNA content had a marginal impact on survival as evaluated by univariate analysis (69% vs. 61% 10-year survival rate, P = 0.06). Multivariate analysis revealed that significant predictors of outcome were lymph node metastasis (95% confidence interval of relative risks of death from recurrent disease, 1.50-2.92), rectal cancer (1.22-2.19), absence of lymphocytic infiltration (1.20-2.17), invasion through bowel wall (1.17-3.13), lymphatic vessel invasion outside bowel wall (1.05-2.69), perineural invasion (1.15-3.19), and male gender (1.00-1.79). CONCLUSIONS: These findings suggest that ploidy is associated with some histopathologic parameters, but flow cytometry does not correlate with long term survival of patients with colorectal carcinoma.

Adult↗
PubMed1995

Overexpression of cyclin D2 in chronic B-cell malignancies.

Tumor progression in B-cell chronic lymphocytic leukemia (B-CLL) is thought to result from the gradual accumulation of small resting G0/G1 phase lymphoid cells rather than the proliferation of actively dividing cells. The recent identification of G1 cyclins that are likely to control both the progression through G0 and G1 phase and the G1/S transition prompted us to study the mRNA expression of D-type cyclins in the peripheral blood lymphocytes from 34 patients with B-CLL, 7 patients with lymphoplasmacytic lymphoma (LPL), and 2 patients with mantle cell lymphoma (MCL). Cyclin D2 mRNA was, on average, 5- to 10-fold overexpressed in most of the samples studied (B-CLL, 29/34; LPL, 7/7; MCL, 0/2) as compared with normal resting B lymphocytes, in which cyclin D2 mRNA was barely detectable. In situ hybridization with cyclin D2 digoxigenin-labeled mRNA probe showed that all the cells from a given sample were stained with approximately the same intensity. Cyclin D3 was never detected in any of the samples tested, whereas cyclin D1 was expressed in only the 3 cases (1 LPL and 2 MCL) bearing a t(11;14) translocation. A trisomy 12 was found in 4 of 19 (21%) B-CLL or LPL cases for which cytogenetic analysis was available. Although the cyclin D2 gene has been mapped to chromosome 12p13, there was no apparent correlation between trisomy 12 and the level of cyclin D2 expression. Cell cycle analysis by flow cytometry after staining with propidium iodide consistently showed that more than 96% of the cells were in G0/G1 phase, whatever the importance of cyclin D2 overexpression was, and that cyclin D2 overexpression in B-CLL was not associated with any modifications of the cell cycle repartition. No consistent overexpression of cyclin D2 was found in acute myeloid leukemias. In conclusion, overexpression of cyclin D2 mRNA was found to be an almost constant feature in B-CLL and LPL. Therefore, it led us to hypothesize, with the support of data from some transfection experiments previously reported in murine hematopoietic cell lines, that cyclin D2 might play a role in B-CLL pathogenesis, possibly by preventing cells from programmed cell death.

Cyclin D2↗
PubMed1995

Effects of nitric oxide on human and canine prostates.

OBJECTIVES: To determine whether nitric oxide (NO) is a mediator of prostatic smooth muscle activity. METHODS: Pharmacologic experiments using electrical field stimulation (EFS) were performed on strips of human and canine prostate. RESULTS: EFS alone elicited frequency-dependent contractions in preparations of human and canine prostates. The greatest contractile activity was achieved at 30 Hz. In the presence of 10(-5) M guanethidine (GUA) and 2 x 10(-6) M atropine (ATR), EFS elicited relaxation of canine prostate strips relative to baseline tension. A weak biphasic response consisting of initial relaxation and subsequent contraction relative to baseline tension was observed in the human prostate strips exposed to similar conditions. The smooth muscle activity observed in the presence of GUA plus ATR was attributed to nonadrenergic, noncholinergic (NANC) nerve transmission. 10(-4) M L-NG-nitroarginine methylester (NAME) significantly increased EFS-elicited NANC smooth muscle activity both in human and canine prostates. L-arginine, 10(-2) M, reversed the effect of L-NAME in human and canine prostates. Sodium nitroprusside, 10(-4) M, a donor of NO, caused relaxation of both human and canine prostates. The mean magnitude of the relaxant response/cross-sectional area in human prostate (2.64 +/- 0.4 g/cm2) was significantly greater than in the canine prostate (1.09 +/- 0.17 g/cm2) (P < 0.005). CONCLUSIONS: These results provide compelling evidence that NO plays a role in mediating contractile function of human and canine prostates.

Animals↗
PubMed1995

Over-expression of cyclin D1 in chronic B-cell malignancies with abnormality of chromosome 11q13.

Accurate identification of B-cell chronic malignancies is sometimes uncertain, despite careful cytologic and immunophenotypic evaluation. Cytogenetics and molecular biology studies may therefore prove useful, because some of these disorders are associated with non-random abnormalities, such as the t(11;14)(q13;q32) translocation and bcl-1 rearrangement mainly observed in mantle-cell lymphoma (MCL). We studied the expression of cyclin D1 in malignant lymphoid cells from the peripheral blood of 32 patients with various B-cell chronic lymphoproliferative disorders, using Northern blot (NB) and RNA in situ hybridization (ISH). Cytogenetic analysis was informative in 18 cases, and most of the missing karyotype data were from typical B-CLL cases where a t(11;14) is unlikely to be found. Over-expression of cyclin D1 mRNA was observed by both NB and ISH in four samples (MCL; two cases; lymphoplasmacytic lymphoma: one case, unclassified B-cell chronic disorder: one case). In each of these cases there was an abnormality of chromosome 11q13, either a t(11;14)(q13;q32) translocation (three cases) or a del(11)(q13) without evidence of chromosome 14 involvement (one case). Cytogenetic and gene rearrangement studies are not available in all institutions and have some technical pitfalls. Because of its close association with bcl-1 rearrangement and/or t(11;14), the demonstration of cyclin D1 mRNA over-expression either by NB, or, more conveniently, by ISH, may represent additional information which could be of help for the identification of B-cell malignancies.

Aged↗
PubMed1995

Localization of the alpha 1A-adrenoceptor in the human prostate.

PURPOSE: We determined the tissue localization of the alpha 1a-adrenoceptor in the human prostate. MATERIALS AND METHODS: Autoradiographic localization of the alpha 1a-adrenoceptor in the human prostate was determined by performing competitive displacement experiments on slide mounted tissue sections using the ligand 125iodine-2-(-[4-hydroxyphenyl]-ethyl-aminomethyl)tetralone (125I-Heat), and the alpha 1-antagonists WB-4101 (4 x 10(-8) M.) and 5-carboxamido-2,6-diethyl-1,4-dihydro-3-[N-(3-[4-hydroxy-4-phenylpipe ridin- yl]propyl)]carboxamido-4-(4-nitrophenyl) (SNAP 5272, 3 x 10(-7) M.). Under these experimental conditions, WB-4101 and SNAP 5272 are selective alpha 1a/alpha 1d-adrenoceptor and alpha 1a-adrenoceptor antagonists, respectively. The autoradiographs were quantitatively analyzed using a computer image analysis system. RESULTS: Specific 125I-Heat binding associated with the epithelium and stroma were independently analyzed. WB-4101 and SNAP 5272 inhibited 100% of the specific 125I-Heat binding in the stroma, suggesting that all of the stromal alpha 1-adrenoceptors are of the alpha 1a subtype. WB-4101 inhibited none of the specific 125I-Heat binding in the epithelium, suggesting that the alpha 1-adrenoceptor in the epithelium is of the alpha 1b subtype. SNAP 5272 displaced only 25% of the specific 125I-Heat binding in the epithelium, suggesting that a relatively small percentage of the epithelial alpha 1-adrenoceptor is of the alpha 1a subtype. CONCLUSIONS: To our knowledge, our study represents the first cellular localization of the alpha 1-adrenoceptor subtypes in the human prostate using highly selective alpha 1-adrenoceptor antagonists and is consistent with the physiological observation that the activity of prostatic smooth muscle is mediated by the alpha 1a-adrenoceptor.

Adrenergic alpha-Antagonists↗
PubMed1995

Modified distal osteotomy of shortening the first metatarsal and for treatment of hallux valgus.

We evaluated the results of distal osteotomy of shortening the first metatarsal head with internal fixation of shape memory metal compression staple for hallux valgus in 26 feet of 17 women with a mean age of 41.0 years (30-65 years). The time for return to light work averaged 18.2 days, and to full work and normal walking 40.3 days after the operation. 16 patients (25 feet) had complete pain relief. Only in one foot, the pain was transferred under the 2nd metatarsal head. The appearance of the feet was markedly improved and the width of the forefeet was decreased by a mean of 0.92 cm after the operation. All of the patients were satisfied with the appearance of their feet. Radiographic analysis of feet showed that all osteotomies united, and the average angle of hallux valgus was improved from 30.1 degrees to 16.0 degrees, with the mean intermetatarsal angle of 11.2 degrees-6.5 degrees. No external fixation of plaster splintage was used and the distal fragment during healing of the osteotomy was stable. The time of bone healing was shortened and patients were allowed to bear weight at early stage.

Adult↗
PubMed1995

[Constituents of the petroleum ether and ethyl acetate extract fractions from Dracaena cochinensis (Lour.) S.C. Chen].

Six constituents have been isolated from the petroleum ether and ethyl acetate extract fractions of Dracaena cochinensis. Their structures have been identified as 1,2,4,5-tetrachloro-3,6- dimethoxy-benzene,docosyl alcohol, octadecyl acetate, eicosyl acetate, resveratrol and 4',7-dihydroxy-flavone on the basis of physical, chemical and spectral deta. Of these compounds 1,2,4,5-tetrachloro-3,6-dimethoxy-benzene is a new one.

Chlorobenzenes↗
PubMed1995

Alterations of cyclin-dependent kinase 4 inhibitor (p16INK4A/MTS1) gene structure and expression in acute lymphoblastic leukemias.

The cyclin-dependent kinase 4 (cdk4) inhibitor (p16INK4/MTS1/CDKN2) gene has been recently identified as a putative tumor suppressor gene because of the high frequency of homozygous deletion observed in numerous human tumor cell lines, including leukemias. However, results obtained from uncultured tumor samples have led to discussion of the relevance of these findings. Using reverse transcriptase polymerase chain reaction (RT-PCR) and Southern blot analysis, we have investigated p16INK4A gene at both RNA and genomic levels in various types of leukemias: acute myeloid leukemia (AML) (n = 23); acute lymphocytic leukemia (ALL) (n = 22) and B cell chronic lymphoproliferative disorders (CLPD) (n = 33). p16INK4A mRNA expression was not found in only 1/20 AML and 2/23 CLPD samples. Conversely, p16INK4A mRNA was not detected in 5/17 ALL cases, and intensity of PCR products were barely detectable in seven additional cases, possibly related to the contamination by normal cells in some cases. By Southern blotting, a homozygous deletion of p16INK4A gene was found in 6/17 ALL cases (35%) among which 4/6 were negative or weakly positive by RT-PCR assay. None of the five AML and 20 CLL samples studied had p16INK4A deletion. Sequence analysis of p16INK4A exon 2 did not show point mutation in two of these cases lacking mRNA expression. Our data provide further evidence that among hematological malignancies, ALL are the most likely to be associated with p16INK4A inactivation, mainly by homozygous gene deletion. Since most hematological malignancies-except ALL-are infrequently associated with p16INK4A and retinoblastoma (Rb) gene alteration it seems worthwhile to explore cdk4 and cdk6 expression to determine whether or not the disruption of the p16INK4A/Rb/cdk4/cdk6 regulatory loop might play a role in their pathogenesis.

Base Sequence↗
PubMed1995

Survival impact of lymph node metastasis in TNM stage III carcinoma of the colon and rectum.

BACKGROUND: Node-positive (TNM stage III) adenocarcinoma of the colon and rectum consists of tumors with a widely variable prognosis. To predict the outcome of patients with stage III carcinoma, we assessed the survival impact of the number and level of lymph node metastasis and other clinicopathological variables. STUDY DESIGN: A retrospective study was performed on 538 patients with stage III carcinoma of the colon and rectum who underwent curative resection at Chang Gung Memorial Hospital between 1980 and 1989. Ten or more lymph nodes in each resected specimen were identified microscopically. Multivariate analysis was used to determine the independent variables. RESULTS: The relative survival rates at five and ten years were 52 and 42 percent, respectively. Tumor morphology, depth or tumor penetration, histologic grade, and the status (number and level) of nodal involvement were significant in the univariate analyses. Only grade and nodal status remained significant in the multivariate analysis. Based on the nodal status, these patients were separated into three groups: stage IIIA (one to three positive nodes and absence of pN3 metastasis), IIIB (four to nine nodes and absence of pN3), and IIIC (ten or more nodes or presence of pN3). The five-year survival rates for patients with stages IIIA, IIIB, and IIIC disease were 69, 44, and 29 percent, respectively. Compared with patients with stage IIIA disease, the odds of death for patients with stages IIIB and IIIC carcinoma were 2.1 (95 percent confidence interval: 1.5 to 2.8, p = 0.0001) and 3.3 (95 percent confidence interval 2.4 to 4.5, p = 0.001), respectively. CONCLUSIONS: We suggest that stage III adenocarcinoma of the colon and rectum be divided into three substages: IIIA (one to three positive nodes and absence of pN3 metastasis), IIIB (four to nine nodes and absence of pN3), and IIIC (ten or more positive nodes or presence of pN3.

Adenocarcinoma↗
PubMed1995

Presacral tumor: a review of forty-five cases.

Forty-five patients with primary presacral tumors underwent their treatment at Division of Colon Rectal Surgery, Chang Gung Memorial Hospital, from 1978 to 1992. These 45 patients, 20 male and 25 female, ranged from 15 to 76 years of age (mean, 41.1 years). Congenital tumors (47 per cent) were the most frequent histologic type, followed by miscellaneous tumors (36 per cent). Forty-eight per cent of patients had malignant tumors. All benign congenital cysts were in females. These tumors presented a variety of symptoms and signs. Diagnosis could be made by digital examination in 43 (96 per cent) of the patients. Computed tomographic scan was the most important diagnostic tool in determining the extent and degree of tumor invasion. The positive rate was 100 per cent in 21 patients. As for operative methods, abdominal approach was selected in 24 patients, transacral in 13 patients, abdominal/sacral combined in 6 patients, and biopsy only in two patients. Postoperative complications occurred in 16 patients (36 per cent), but there were no operative deaths. Of the tumors that underwent resection, 23 had total resection (18 benign and 5 malignant) and 22 incomplete (5 benign and 17 malignant). Benign tumors had a good chance with resection of the lesion (P < 0.05). For patients with malignant tumors, the 5-year survival rate was 40.7 per cent. Whenever possible, total resection could offer better results for presacral tumor, whether the lesions were benign or malignant.

Adolescent↗
PubMed1995

[Modified distal osteotomy of shortening the first metatarsal for treatment of hallux valgus].

The results of distal osteotomy of shortening the first metatarsal with internal fixation of shape, memory metal compression staple for hallux valgus were evaluated in 26 feet of 17 women with a mean age of 41.0 years (30-65 yrs). The average time for return to light work was 18.2 days, and to full work and normal walk 40.3 days after the operation. 16 patients (25 feet) had complete relief from pain. Only in one foot the pain was transferred under the 2nd metatarsal head. The appearance of the feet was apparently improved and the width of the forefeet was decreased in a mean 0.92cm after the operation. All of the patients were satisfied with the appearance of their feet. Radiographic analysis of feet showed that all the osteotomies united, the average angle of hallux valgus was improved from 30.1 degrees to 16.0 degrees and the mean intermetatarsal angle from 11.2 degrees to 6.5 degrees. This new technique allows no external fixation of plaster splintage and the distal fragment during healing of the osteotomy was stable. The time of bone healing was shortened and patients were allowed to bear weight at early time.

Adult↗