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Biomedical subjects

R Tang

Publications and source records attributed to R Tang.

At least 127 records · Page 7Linked to original sources
PubMed1994

Anti-colony-stimulating factor-1 antibody staining in primary breast adenocarcinomas correlates with marked inflammatory cell infiltrates and prognosis.

BACKGROUND: Clinical studies have shown that a marked lymphoplasmocytic reaction in breast tumors is associated with poor prognosis. Such findings raise the possibility that an inflammatory cell reaction might be a tumor-induced response that tends to promote tumor growth. PURPOSE: We assessed the expression of colony-stimulating factor-1 (CSF-1) as well as the prevalence of specific tumor-infiltrating lymphocytes and monocytes in breast tumors. METHODS: Tissue sections were obtained from archival paraffin blocks from 196 breast cancer patients. Seventy-eight percent of the women had been treated by mastectomy and 22% by lumpectomy. Median age of the patients was 54 years, and median follow-up was 7.3 years. Immunohistochemical and in situ hybridization techniques were used to characterize the specimens. RESULTS: Markedly high numbers of CD45RO-positive T- and L26-positive B-cell infiltrates were found in 13% and 17% of the tissue specimens, respectively. CSF-1 receptor-positive monocytes were detected in 48% and CD68-positive monocytes in 90% of the tumors. In turn, tumors with large fractions of CD68-positive monocytes also showed CSF-1 receptor-positive monocytes (P < .0001). CSF-1 was expressed significantly in 74% of the tumors and the CSF-1 receptor in more than 50% of the tumors. Tumors with high percentages of CSF-1 expressing cells also had marked monocyte infiltrates (P = .035). The presence of marked CD45RO-positive T-cell infiltrates and apparent nuclear staining of CSF-1 in tumor cells were associated with the more frequent occurrence of metastases (P = .02 and P = .04, respectively) and with poor survival (P = .02 and P = .03, respectively). CONCLUSIONS: Large numbers of CD45RO-positive (activated memory but noncytotoxic) T cells as well as a predominant nuclear staining pattern for CSF-1 are associated with a poor outcome in breast cancer patients. IMPLICATIONS: Nuclear retention of CSF-1 could reflect CSF-1 turnover and function in tumor cells, but new approaches are needed to establish the significance of these observations. Secreted CSF-1 appears to cause monocyte recruitment and activation, thereby modulating immune functions and potentially the expression of the CD45RO phenotype in T cells.

Adenocarcinoma↗
PubMed1994

Value of carcinoembryonic antigen in the management of colorectal cancer.

PURPOSE: The practical value of carcinoembryonic antigen (CEA) assay in the management of colorectal cancer after surgery is controversial. The value of CEA in the management of colorectal cancer was reviewed and discussed to justify the use of CEA assay in the management of colorectal cancer. METHODS: A retrospective study was performed on 318 patients who underwent resection by one surgeon (JYW) between 1981 and 1986 and who were followed for a minimum of 5 years or until death. RESULTS: The incidence of preoperative CEA levels > 5 ng/ml in Dukes Stages A, B, C, and D were 0, 32, 48, and 79 percent, respectively. Five-year survival rates for groups with CEA levels < or = 5 ng/ml and > 5 ng/ml were 85 percent and 55 percent (P < 0.05), respectively, in Dukes Stage B patients and 64 percent and 37 percent (P < 0.05) in Stage C patients. The sensitivity and specificity of postoperative CEA monitoring in detecting recurrent diseases were 66 percent and 94 percent, respectively, for patients with a preoperative CEA value < or = 5 ng/ml and 97 percent and 88 percent for patients with a higher preoperative CEA value. CONCLUSION: CEA is still the best tumor marker available to be used as an independent prognostic factor and as a monitor for recurrence of disease after primary tumor resection.

Adenocarcinoma↗
PubMed1994

The effect of cell density on the production of xylitol from D-xylose by yeast.

The rate of xylitol production from D-xylose increased with increasing yeast cell density. The optimal temperature for xylitol production is 36 degrees C, and the optimal pH range is from 4.0 to 6.0. At high initial yeast cell concentration of 26 mg/mL, 210 g/L of xylitol was produced from 260 g/L of D-xylose after 96 h of incubation with an indicated yield of 81% of the theoretical value.

Candida↗
PubMed1994

Localization of endothelin receptors in the human prostate.

The objective of the present study was to localize endothelin receptors in the human prostate using quantitative autoradiography. Slide-mounted tissue sections 20 microns. in thickness were obtained from the transition zones of seven patients undergoing radical prostatectomies for low volume prostate cancer. Sarafotoxin (S6C) and BQ123 have been used to distinguish endothelin receptor subtypes (ETA and ETB). The prostatic tissue sections were incubated in four different stock solutions containing the following: 0.1 nM. 125I-endothelin-1 (125I-ET-1) (total ET-1 binding); 0.1 nM. 125I-ET-1 and 100 nM. S6C (total ETA binding); 0.1 nM. 125I-ET-1 and 1 microM. BQ123 (total ETB binding); and 0.1 nM. 125I-ET-1 and 1 microM. ET-1 (nonspecific ET-1 binding). Nonspecific binding accounted for only 12 and 15% of total 125I-ET-1 binding in the stroma and glandular epithelium. Autoradiograms were quantitatively analyzed using a computerized image analysis system. Specific radioactive densities (nCi/mg.) were determined for the stromal and glandular epithelial elements of the prostate. The specific radioactive densities of ETA and ETB binding sites in the stroma were 7.57 +/- 0.65 and 2.98 +/- 0.81. The specific radioactive densities of ETA and ETB binding sites in the glandular epithelium were 1.59 +/- 0.15 and 7.87 +/- 1.35. The present study demonstrates that the predominant endothelin receptors in the stroma and glandular epithelium are the ETA and ETB subtypes, respectively.

Autoradiography↗
PubMed1994

Premature carotid atherosclerosis: does it occur in both familial hypercholesterolemia and homocystinuria? Ultrasound assessment of arterial intima-media thickness and blood flow velocity.

BACKGROUND AND PURPOSE: Homocystinuria due to cystathionine beta-synthase deficiency and familial hypercholesterolemia are inherited disorders of metabolism that are associated with premature development of cardiovascular disease. This study addresses the possibility that different patterns of carotid wall damage and cerebral blood flow hemodynamics are present in these two metabolic diseases. METHODS: Twelve patients with homocystinuria due to cystathionine beta-synthase deficiency (mean age, 24 years), 10 patients with homozygous familial hypercholesterolemia (mean age, 26 years), and 11 healthy control subjects (mean age, 26 years) underwent a vascular examination by noninvasive methods. B-mode ultrasound imaging was used to obtain measurements of intima-media thickness of common carotid, bifurcation, and internal carotid arteries as an index of atherosclerosis. Cerebral blood flow velocity was estimated from vascular examination of the middle cerebral artery by transcranial Doppler. Systolic, diastolic, and mean velocities were measured. Pulsatility index, a possible indicator of vascular resistance in the cerebral circulation, was also calculated. RESULTS: Mean maximum intima-media thickness was 1.4 mm in patients with familial hypercholesterolemia, 0.6 mm in patients with homocystinuria, and 0.6 mm in control subjects. The difference between hypercholesterolemic and homocystinuric patients or control subjects was statistically significant (P < .001). Diastolic blood flow velocities were significantly reduced in the middle cerebral arteries of hypercholesterolemic patients compared with homocystinuric patients or control subjects (P < .05), whereas systolic or mean velocities did not differ. The pulsatility index, a possible indicator of vascular resistance in the cerebral circulation, was significantly higher in hypercholesterolemic patients compared with homocystinuric patients or healthy control subjects (P < .01). A direct relation was demonstrated between pulsatility index of the middle cerebral artery and mean maximum intima-media thickness of carotid arteries on the same side (P < .001). CONCLUSIONS: Familial hypercholesterolemia is responsible for diffuse and focal thickening of carotid arteries and possibly also for hyperlipidemic endothelial dysfunction extending to small resistance arteries and leading to a disturbed cerebral blood flow. Patients with homocystinuria due to homozygosis for cystathionine beta-synthase deficiency seldom have plaques in their carotid arteries. They are similar to healthy control subjects with regard to both intima-media thickness and blood flow velocity in the middle cerebral artery. Therefore, it is unlikely that typical atherosclerotic lesions precede thrombotic events in homocystinuria. However, it is possible that arterial dilatations caused by medial damage lead to thrombosis in homocystinuric patients.

Adolescent↗
PubMed1994

A comparison of the binding and functional properties of alpha-1 adrenoceptors and area density of smooth muscle in the human, canine and rat prostates.

The present study was designed to compare the binding and functional properties of alpha-1 adrenoceptors and the area density of smooth muscle in the human, canine and rat prostates. Chloroethylclonidine (CEC)-sensitive and -insensitive alpha-1 adrenoceptors were characterized on slide-mounted prostatic tissue sections using the ligand [3H]prazosin. The mean equilibrium dissociation constants (Kd) for [3H]prazosin binding sites were not significantly different among the three different species. The densities (Bmax) of CEC insensitive [3H]prazosin binding sites in the human, canine and rat prostates were 1.71 +/- 0.32, 0.35 +/- 0.04 and 0.84 +/- 0.11 fmol/mg of wet weight, respectively. The Bmax of CEC-sensitive [3H]prazosin binding sites in the human, canine and rat prostates were 1.32 +/- 0.83, 0.44 +/- 0.11 and 0.25 +/- 0.10 fmol/mg of wet weight, respectively. The contractile response elicited by the rat prostate in the presence of phenylephrine was consistently negligible. The mean maximal force after phenylephrine challenge (phenylephrine Emax) in the human and canine prostates were 0.125 +/- 0.025 g of force/mm2 cross-sectional area and 0.096 +/- 0.014 g of force/mm2 cross-sectional area, respectively. CEC inactivated 80 and 53% of the phenylephrine contractile response in man and dog, respectively. The mean percentage of area densities of smooth muscle in the human, canine and rat prostates were 38.8, 12.9 and < 1%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Binding and functional properties of endothelin receptor subtypes in the human prostate.

The objective of the present study was to characterize the binding and functional properties of endothelin (ET) receptor subtypes in the human prostate. Human prostatic tissue was obtained from male subjects undergoing radical prostatectomy for low-volume prostate cancer. The optimal assay conditions for characterizing human prostatic ET-1 binding sites on slide-mounted tissue sections were defined. Maximal specific 125I-ET-1 binding was achieved after a 10-min preincubation, a 120-min incubation, and a washing procedure that consisted of a brief rinse and a 1-min wash. The mean equilibrium dissociation constant (Kd) and density (Bmax) of ET-1 binding sites determined from six saturation studies were 0.72 +/- 0.13 nM and 40.4 +/- 6.9 fmol/mg of wet weight, respectively. The mean Hill coefficient was 0.99 +/- 0.01, indicating that 125I-ET-1 identifies a single population of binding sites. The pharmacology of 125I-ET-1 binding sites was characterized using competitive binding experiments. The competition plots for ET-1 were best fit by a one-binding site model, whereas the plots for sarafotoxin 6C (S6C) and BQ123 were consistently best fit by a two-site model. The mean Ki value of ET-1 was 0.34 +/- 0.12 nM. The mean Ki values for the high and low affinity S6C binding sites were 0.50 +/- 0.09 nM and 0.84 +/- 0.28 microM, respectively. The mean Ki values for the high and low affinity BQ123 binding sites were 5.51 +/- 1.05 nM and 24.9 +/- 6.5 microM, respectively. The ratio of ETA to ETB binding sites was approximately 2:1. The ET receptor subtype mediating prostatic smooth muscle tension was investigated using agonist-antagonist competition studies. ET-1, a nonselective ET agonist, elicited a potent contraction of prostate smooth muscle. The pA2 of BQ123 for inhibiting ET-1-mediated contraction was 6.84. S6C, a selective ETB agonist, also elicited a potent contraction of prostate smooth muscle. BQ123 at concentractions between 0.1 and 10 microM did not shift the S6C dose-response curve. These functional studies suggest that both ETA and ETB receptors mediate the tension of prostate smooth muscle. Endogenous ETS may be involved in the pathophysiology of bladder outlet obstruction in men with benign prostatic hyperplasia. If this is the case, then ET antagonists may represent effective treatment for benign prostatic hyperplasia.

Binding, Competitive↗
PubMed1994

The alpha 1-adrenergic receptor that mediates smooth muscle contraction in human prostate has the pharmacological properties of the cloned human alpha 1c subtype.

Molecular cloning studies have revealed the existence of three subtypes of alpha 1-adrenergic receptors. However, the link between any individual subtype and its functional role in the body has remained elusive. In an effort to bridge the gap between molecular biology and pathophysiology, we have chosen a model smooth muscle system, the human prostate, and investigated the role of alpha 1 subtypes in this tissue. To determine which alpha 1-adrenergic receptor subtype mediates the contractile response of the human prostate, we first studied the pharmacological properties of three cloned human alpha 1 subtypes (alpha 1a/d, alpha 1b, and alpha 1c). Prazosin, terazosin, doxazosin, alfuzosin, and abanoquil showed no selectivity for the human alpha 1 subtypes. WB-4101 and 5-methylurapidil showed a rank order of potency of alpha 1c > alpha 1a/d >> alpha 1b. Indoramin and (+)-niguldipine were selective for the alpha 1c-adrenergic receptor, with at least 10-fold lower affinity at either alpha 1a/d or alpha 1b subtypes. SK&F104856 was found to be 6-fold more potent at the alpha 1a/d receptor subtype than at alpha 1b- or alpha 1c-adrenergic receptors. We next determined the potency of these antagonists to inhibit the phenylephrine-induced contraction of human prostatic tissue in vitro. The potencies of indoramin, 5-methylurapidil, and SK&F104856 to inhibit the contractile response and to displace [3H]prazosin from the cloned human alpha 1c subtype were similar. Our data suggest that the alpha 1 receptor that mediates the contraction of human prostate smooth muscle has the pharmacological properties of the cloned human alpha 1c-adrenergic receptor. The findings of the present study suggest that selective alpha 1c-adrenergic receptor antagonists may be clinically more efficacious and better tolerated agents for the treatment of symptomatic benign prostatic hyperplasia.

Animals↗
PubMed1994

[Effect of cypermethrin on some reproductive factors in Culex (C) quinquefasciatus Say 1823].

An experiment was carried otu with a Culex quinquefasciatus strain with resistance genes called "Quibú", and with a susceptible strain provided by the WHO; they were pressured with different lethal doses of cypermetrine. Time-mortality regression lines of the 2 strains were estimated following WHO methodology and the "Quibú" strain showed tolerance to the insecticide. TL30 and TL70 were selected to test their effect on fecundity, fertility, sexual index, and egg eclosion time. A significant reduction in fecundity and fertility was observed in the "Quibú" strain after it was pressured, no effect was detected on the sexual index and egg eclosion time in this strain.

Animals↗
PubMed1994

[Status of insecticide resistance in 4 strains of Musca domestica collected in animal farms].

Resistance to insecticides made from different chemical compounds were studied in 4 strains of Musca domestica collected from 2 poultry farms and 2 cow farms following WHO methodology. A high resistance to malathion was observed (resistance factor values ranging from 102X to 252X), and moderate, to diazinon, fenthion, dichlorvos, DDT, and propoxur. Resistance to the deltametrine and permethrin pyreturins was not observed.

Animal Husbandry↗
PubMed1993

The association between perioperative blood transfusion and survival of patients with colorectal cancer.

BACKGROUND: The authors undertook this study to test the hypothesis that perioperative blood transfusion has an adverse effect on survival of patients with colorectal cancer. METHODS: A retrospective analysis was performed on 725 patients who underwent curative resection for Dukes Stage B and C colorectal cancers in our institution between 1981-1985 and who were followed for 5-11 years. RESULTS: Rectal cancers occurred more frequently in the transfused than in the nontransfused patients (64% versus 47%; P = 0.0001). In the patients with colon cancer, no significant effect of transfusion on recurrence-free survival was seen (P = 0.8, log-rank; P = 0.49, Cox regression analysis). The cumulative 5-year survival rate was 77% (95% confidence interval, 69-85%) for the nontransfused and 78% (72-83%) for the transfused patients. In patients with rectal cancer, the 5-year survival rate was 79% (67-87%) for the nontransfused and 67% (59-71%) for the transfused patients. A significant association was noted in patients with Stage B cancer (P = 0.002, log-rank; P = 0.02, Cox regression analysis), but not in those with Stage C cancer (P = 0.05, log-rank; P = 0.15, Cox regression analysis). In patients with Stage B rectal cancer, more frequent abdominoperineal resections (APR) were performed among the transfused patients (65% versus 32%; P = 0.0001). This subgroup was further stratified by operative procedure and reanalyzed using the same Cox regression model. Transfusion had no effect on survival of patients treated by APR (P = 0.31) or of those having a sphincter-saving procedure (P = 0.53). CONCLUSION: The seemingly adverse effect of perioperative blood transfusion on the survival of patients with colorectal cancer may be explained by other covariates.

Adolescent↗
PubMed1993

An alternative treatment of anal squamous cell carcinoma: combined radiotherapy and chemotherapy.

The conventional surgical treatment of anal squamous cell carcinoma is abdominoperineal resection. A new approach of combined radiotherapy and chemotherapy has been proposed following the observation of excellent local control. In this retrospective study, 40 cases of primary anal squamous cell carcinoma without distant metastasis were collected between 1979 and 1986 and the individual prognosis of the above two methods of treatment was evaluated. Group I (20 cases) received abdominoperineal resection with or without postoperative radiotherapy. Postoperative radiation was given if regional lymph node biopsy was positive. Group II (20 cases) received combined radiotherapy and chemotherapy with or without wide local excision. Radiation was delivered to the anus, pelvis, and bilateral inguinal nodal areas to a total dose of 5,500 rads. A continuous infusion of 5-FU was started on day 2 of the irradiation at a dose of 1,000 mg/m2 body surface/day for 5 days and a bolus injection of mitomycin was given on day 2 at a dose of 10 mg/m2 body surface. The second course was given 1 month later to complete the chemotherapy. The wide local excision was performed if the disease still persisted after completion of combined radiotherapy and chemotherapy. All 40 cases were followed up for at least 5 years. All cases (100%) in group I survived 1 year, 18 cases (90%) 2 years, 14 cases (70%) 3 years, 10 cases (50%) 4 years, and 6 cases (30%) 5 years. Twenty cases (100%) in group II survived 1 year, 17 cases (85%) 2 years, 13 cases (65%) 3 years, 8 cases (40%) 4 years, and 5 cases (25%) survived 5 years. All the mortalities in both groups died of distant metastasis or abdominal carcinomatosis. From the above results, the overall survival rate of combined radiotherapy and chemotherapy was not significantly worse than that of conventional abdominoperineal resection. In conclusion, combined radiotherapy and chemotherapy may be chosen as an alternative management in treating anal squamous cell carcinoma.

Adult↗
PubMed1993

The alpha-adrenoceptor subtype mediating the tension of human prostatic smooth muscle.

We have characterized the alpha 1 adrenoceptor subtypes in the human prostate using radioligand receptor binding studies. The objective of the present study was to determine the alpha 1 subtype mediating the tension of prostatic smooth muscle. Fresh human tissue was obtained from 9 males between 50 and 80 years of age undergoing prostatectomy for BPH. The incubation of prostatic tissue with the irreversible antagonist chlorethyclonidine (CEC) resulted in an 80% reduction of the maximal contractile response produced by phenylephrine. However, the alpha 1A-selective antagonists WB-4101 and 5-methylurapidil (5-MU) competitively inhibited the contractile response induced by phenylephrine, with KB = 2.64 and 4.46 nM, respectively, consistent with their affinity at the alpha 1A receptor subtype. The pharmacological profile of the alpha 1-receptor-mediated contractile response of prostate smooth muscle is inconsistent with their classification as either an alpha 1A or alpha 1B subtype. Alternatively, when compared with the properties of the cloned alpha 1 receptors, our results suggest that the alpha 1 receptors involved in the contraction of prostate smooth muscle have some pharmacological properties similar to those encoded by the gene of the bovine alpha 1C receptor subtype. The findings of the present study suggest that efforts should be made to confirm the identity of the alpha 1-receptor subtype expressed by prostate smooth muscle, in order to develop subtype-selective alpha 1 antagonists, and to evaluate their safety and efficacy in benign prostatic hyperplasia (BPH).

Adrenergic alpha-Antagonists↗
PubMed1993

Binding and functional properties of alpha1 adrenoceptors in different regions of the human prostate.

The objective of the present study was to determine the density and functional properties of alpha 1 adrenoceptors in different regions of the human prostate. Binding and functional studies were performed on eight different topographical regions of the prostate. The contractile response (gm. force/mm.2 cross-sectional area [CSA]) was determined at varying concentrations of phenylephrine, and saturation experiments were performed at seven different concentrations of 125I-Heat. The maximal response to phenylephrine (Emax) ranged from 0.067 to 0.272 gm. force/mm.2 The CSA and the EC50 ranged from 25 to 41 microM. The differences between EC50 and Emax were not significantly different among the eight prostatic regions. A 1.8-fold difference between the Emax for peripheral and central regions of the prostate was statistically significant (p = 0.04). The equilibrium dissociation constant (Kd) of 125I-Heat and the receptor density Bmax were determined from the Scatchard plots. The mean Kd and Bmax ranged from 0.15 to 0.26 nM. and 0.30 to 0.72 fmol. per mg. wet weight, respectively. There were no statistically significant differences between mean Kd and mean Bmax for the eight prostatic regions. The 1.7-fold difference between central and peripheral mean Bmax was not statistically significant (p = 0.07). A direct relationship was not observed between phenylephrine mean Emax and mean Bmax. The present study demonstrates regional differences of the binding and functional properties of prostatic alpha 1 adrenoceptors in the human prostate. These regional differences must be taken into account when investigating the pharmacologic and physiologic properties of the prostate.

Humans↗
PubMed1993

Endothelin-1 in the human prostate: tissue levels, source of production and isometric tension studies.

Endothelins mediate contractile responses in many types of vascular and nonvascular smooth muscle. The present study represents the first detailed characterization of endothelins in the human prostate. The objectives of this study were to determine the tissue levels and source of endogenous endothelin-1 (ET1) in the human prostate. The contractile effects of ET1 were also investigated using in vitro isometric tension studies. The mean tissue level of ET1 was 0.58 +/- 0.08 pg./mg. tissue wet weight. Endothelin-like activity was markedly prominent in the glandular epithelium of the human prostate, whereas minimal endothelin-like activity was observed in the prostatic stroma. Strips of human prostatic tissue were suspended in isolated tissue chambers and challenged to a concentration response of ET1. The mean EC50 and Emax for ET1 was 3.2 x 10(-8) M. and 0.12 +/- 0.02 gm. force per mm.2 cross-sectional area (CSA), respectively. Preincubation with indomethacin, terazosin, or nifedipine did not alter the concentration-dependent response to ET1. A calcium-free buffer abolished the contractile response to ET1. Thus, ET1 mediates a potent contraction of human prostatic smooth muscle that is not mediated via alpha 1 adrenergic or dihydropyridine sensitive calcium channels or prostaglandin synthesis. The presence of marked endothelin-like immunoreactivity strongly suggests a biological significance for endogenous endothelins in the human prostate.

Adrenergic alpha-Antagonists↗