Biomedical subjects

Y Liao

Publications and source records attributed to Y Liao.

At least 109 records · Page 6Linked to original sources

PubMed1998

[Clinical and experimental study of Tongqiao tablet in treating catarrhal otitis media].

OBJECTIVE: To assess the effect of Tongqiao tablet (TQT) in treating catarrhal otitis media (COM). METHODS: Ninety-six patients of COM were randomized into two groups, 52 patients in the treatment group were treated with TQT and 44 patients of the control group were treated with western medicine. Animal experiment study on effect of TQT was also carried out. RESULTS: The total effective rate and the cure and markedly improved rate of the treatment group were 92.31% and 53.85% respectively, while those in the control group were 68.18% and 27.27% respectively, the difference between the two groups was significant statistically (P < 0.01). The effect of TQT was superior to that of the western medicine. Experimental study indicated that TQT had remarkable inhibiting effect on inflammation and granuloma formation. CONCLUSION: TQT is an effective drug for treatment of COM.

Adolescent↗

PubMed1998

[Determination of linear sintering shrinkage rate of slip-casting infiltrated ceramic].

This study tested the linear sintering shrinkage (SS) rate of ceramic infiltrated with different glasses (Vita In-ceram, G I-I La, G I-II La, G I-II Ce), the results showed that the linear SS rate was 0.08%-0.32%, which occurred mainly in the firing stage of alumina (P < 0.05) and glass infiltration had no influences on the dimensional stability of ceramic(P > 0.05). It suggests that the effects of glass infiltration on the dimensional stability of GI glasses were comparable with that of Vita In-ceram.

Aluminum Oxide↗

PubMed1998

The relation between income and mortality in U.S. blacks and whites.

Differential mortality exists in the United States both between racial/ethnic groups and along gradients of socioeconomic status. The specification of statistical models for processes underlying these observed disparities has been hindered by the fact that social and economic quantities are distributed in a highly nonrandom manner throughout the population. We sought to provide a substantive foundation for model development by representing the shape of the income-mortality relation by racial/ethnic group. We used data on black and white men and women from the longitudinal component of the National Health Interview Survey (NHIS), 1986-1990, which provided 1,191,824 person-years of follow-up and 12,165 mortal events. To account for family size when considering income, we used the ratio of annual family income to the federal poverty line for a family of similar composition. To avoid unnecessary categorizations and prior assumptions about model form, we employed kernel smoothing techniques and calculated the continuous mortality surface across dimensions of adjusted income and age for each of the gender and racial/ethnic groups. Representing regions of equal mortality density with contour plots, we observed interactions that need to be accommodated by any subsequent statistical models. We propose two general theories that provide a foundation for more elaborate and testable hypotheses in the future.

Adolescent↗

PubMed1997

Synthesis and pharmacological evaluation of triflate-substituted analogues of clozapine: identification of a novel atypical neuroleptic.

The trifluoromethanesulfonyloxy (TfO) analogues 3 and 4 of 8-chloro-11-(4-methyl-1-piperazinyl)-5H-dibenzo[b,e][1,4]diazepine (clozapine, 1) and its 2-chloro isomer (iso-clozapine, 2), respectively, were synthesized via their OMe and OH analogues with the conventional synthetic method of the tricyclic dibenzodiazepines and evaluated pharmacologically along with their parent drugs. The binding profile of the 2-OTf analogue (4) is comparable to the binding profile of 1, although the affinity for the dopamine (DA) D2 receptors is higher (IC50 values are 31 nM and 330 nM for compounds 4 and 1, respectively). Interestingly, no notable affinity for muscarinic receptors could be detected in compound 4. On the contrary, the 8-OTf analogue 3 only displayed affinity for muscarinic M1 receptors (IC50 value 35 nM) and no affinity (IC50 value > 500 nM) for the other receptors tested. The 10 mumol/kg sc dose, but not the 10 mumol/kg po dose, of compound 4 stimulated the output of DA. Increases of 80% and 35% in DOPAC output from the dorsal striatum were seen after sc and po administrations of 10 mumol/kg of compound 4, respectively. Doses up to 100 mumol/kg of compound 3 had no effect on either parameter. Doses up to 100 mumol/kg of compound 4 were not cataleptogenic, but significantly decreased apomorphine-induced locomotor activity. In conclusion, compound 4 (GMC1-169) is a new clozapine-like neuroleptic candidate, which is lacking anticholinergic properties and displays a higher potency, as compared to clozapine (1) itself.

Animals↗

PubMed1997

Mortality from coronary heart disease and cardiovascular disease among adult U.S. Hispanics: findings from the National Health Interview Survey (1986 to 1994).

OBJECTIVES: We sought to estimate the coronary heart disease (CHD) and cardiovascular disease (CVD) mortality experience of U.S. Hispanics. BACKGROUND: Limited information is available concerning the mortality from CHD among U.S. Hispanics, the nation's second largest minority group. METHODS: The study used data from the National Health Interview Survey (1986 to 1994), including representative national samples of 246,239 non-Hispanic whites, 38,042 blacks and 14,965 Hispanics who were > or = 45 years old at baseline. Mean follow-up of mortality was 5 years (range 1 to 10). RESULTS: During the follow-up period, 27,702 whites (11%), 4,976 blacks (13%) and 1,061 Hispanics (7%) died. Among men, the age-adjusted total mortality per 100,000 person-years was 3,089 in whites and 2,466 in Hispanics, and among women, it was 1,897 and 1,581 in whites and Hispanics, respectively. The Hispanic/white mortality rate ratio for CHD was 0.77 (95% confidence interval [CI] 0.64 to 0.93) and 0.82 (95% CI 0.66 to 1.01) for men and women, respectively. The rate ratio was 0.79 (95% CI 0.68 to 0.91) and 0.80 (95% CI 0.69 to 0.94), respectively, for mortality from cardiovascular diseases. Given the lower all-cause mortality in Hispanics, the proportion of total deaths due to CHD and CVD was similar between the two populations for the same gender and were, respectively, 29.7% and 44.7% in white men, 28.1% and 44.3% in Hispanic men, 24.9% and 43.2% in white women and 24.1% and 41% in Hispanic women. CONCLUSIONS: These data from a cohort of a large national sample are consistent with vital statistics that show that all-cause, CHD and CVD mortality is approximately 20% lower among adult Hispanics than among whites in the United States.

Aged↗

PubMed1997

Prediction of mortality risk by different methods of indexation for left ventricular mass.

OBJECTIVES: We sought to compare the predictive value of echocardiographically determined left ventricular hypertrophy on death from all causes and cardiac mortality using various methods of indexation for left ventricular mass. BACKGROUND: Considerable controversy exists regarding the optimal method for indexing left ventricular mass to body size in the clinical setting. METHODS: The study included 988 consecutive patients who had both coronary angiograms and echocardiographic examinations in an inner-city public hospital in Chicago, Illinois. Patients were followed up for a mean of 7 years (range 2 to 11). RESULTS: Various left ventricular mass indexes (e.g., mass indexed for height, height2, height2.13, height2.7, body surface area and body surface area1.5 were highly correlated (r = 0.90 to 0.99). Used as a continuous measure, an increase in any left ventricular mass index was associated with similar risk of death from all causes and cardiac diseases. Although left ventricular hypertrophy assessed by mass indexed for body surface area using the published conventional partition values provided somewhat better prediction, the adjusted relative risk was in general not significantly different from hypertrophy based on other indexes. Patients with left ventricular hypertrophy defined concordantly by indexes based on both body surface area and height (or height2.7) had, by definition, the highest average mass indexes among all groups and experienced as much as a threefold greater risk of death than those without hypertrophy. A small proportion of patients (12%) who were classified into the hypertrophy group by height-based indexes alone, but not by body surface area, had a moderate increase in mass and showed no increase in risk, even though being overweight was extremely prevalent in this group. CONCLUSIONS: Because of the high correlation among various body size indexes, left ventricular hypertrophy, defined by different indexes for left ventricular mass, similarly confers increased risk of mortality in patients with or without coronary artery disease.

Body Constitution↗

PubMed1997

Selective reporter expression in mast cells using a chymase promoter.

Primate alpha-chymases are mast cell neutral proteases that are involved in regulating several regulatory peptides including angiotensin II. Because of significant substrate specificity differences among the chymase group of enzymes, animal models that overexpress primate chymases are crucial for delineating the in vivo function of these enzymes. Activation of alpha-prochymase requires processing enzymes and proteoglycans found in mast cell secretory granules. Thus, the development of models overexpressing active primate chymase requires a mast cell-specific promoter. We show that the 571-base pair (bp) 5'-upstream sequence of the baboon chymase gene, which encodes an alpha-chymase, coupled to the prokaryotic lacZ gene allows the targeting of beta-galactosidase to mast cells in transgenic mice. Tissue expression of the transgene is similar to the expression of the endogenous mouse alpha-chymase mouse mast cell protease-5. A mouse mast cell line that endogenously expresses mouse mast cell protease-5 (JKras mast cells) also selectively supports the expression of this transgene. In vitro transcription studies in JKras mast cells shows the critical role of a GATA cis-regulatory motif in baboon chymase promoter, located approximately 430-bp upstream of the transcription start site. These results suggest that the 571-bp domain of the baboon chymase promoter contains most, if not all, of the mast cell-specific region of the promoter. We describe here for the first time a promoter that directs expression of transgenes specifically to mouse mast cells. This promoter should be generally applicable for dominant expression of mast cell regulatory proteins.

3T3 Cells↗

PubMed1997

Apoptosis of human BEL-7402 hepatocellular carcinoma cells released by antisense H-ras DNA--in vitro and in vivo studies.

Recent findings suggest that over-expression of activated H-ras inhibited apoptotic cell death by blocking the activity of apoptotic endonuclease(s). This study was designed using antisense H-ras oligodeoxynucleotides (ODN) to evaluate whether alterations of H-ras expression in BEL-7402 human hepatocellular carcinoma cells could influence the induction of apoptosis in vitro and in vivo. We found that, in vitro, continuous suppression of H-ras expression could decrease the proliferation of BEL-7402 cells and inhibit H-ras-induced entry into S phase. In situ end labeling showed that a large number of cells underwent apoptotic cell death after treatment with antisense H-ras ODN (P < 0.01), and gel electrophoresis of DNA extracted from these cells demonstrated a typical DNA ladder, characteristic of apoptosis. In vivo study indicated that pretreatment with antisense H-ras significantly retarded tumor growth in comparison with the untreated controls or tumors treated with non-specific ODN (P < 0.01, P < 0.01). In situ end-labeling revealed that pronounced apoptotic nuclei were also present in the tissue treated with antisense H-ras ODN (P < 0.01). Immunocyto-histochemical study showed that expression of p21H-ras was significantly decreased after treatment with antisense H-ras. These results indicate that suppression of H-ras over-expression by antisense ODN could effectively inhibit tumor growth and revive the apoptotic pathway by releasing the activity of apoptotic endonuclease(s). The data also suggest the need for further studies to elucidate molecular events involved in antisense H-ras-released apoptosis and evaluate its therapeutic implications.

Animals↗

PubMed1997

Mechanism of anti-beta-adrenoceptor antibody mediated myocardial damage in dilated cardiomyopathy.

Antibodies against beta(1)-adrenoceptor can be detected in serum of patients with dilated cardiomyopathy (DCM), which have beta-agonist-like activity, and induce a positive chronotropic effect on cardiac myocytes by its persistence at full strength. Effects of the antibodies against beta-adrenoceptor from sera of patients with DCM on myocardial cytotoxicity and cytoplasmic free Ca(2+)-concentration ([Ca2+]i) were observed in the cultured single layer SD rat ventricular cells by using the cytotoxicity assay and fluorescent Ca(2+)-indicator fura-2/AM. The positive sera of the anti-beta-adrenoceptor antibodies from patients with DCM markedly enhanced myocardial [Ca2+]i. Betaloc, a beta(1)-receptor blocker, might inhibit the increase of the antibody-mediated myocardial [Ca2+]i, and the sera from healthy donors had no effect on myocardial [Ca2+]i. Our results suggest that the anti-beta-adrenoceptor antibody might increase myocardial [Ca2+]i and result in myocardial damage. The antibodies might activate receptor-gating Ca(2+)-channel, thereby causing myocardial [Ca2+]i rise and calcium overload. Early use of betaloc is recommended in the treatment of dilated cardiomyopathy.

Adult↗

PubMed1997

Performance of the automated COBAS AMPLICOR system for the detection of hepatitis C virus RNA.

BACKGROUND: The COBAS AMPLICOR (CA) instrument for the amplification and detection steps of the AMPLICOR molecular diagnostic assays has recently been introduced. The system contains a single thermal cycler with two independently controlled heating/cooling blocks, a pipettor, a magnetic particle washer, a photometer and an incubator. OBJECTIVE: The performance of the CA instrument was evaluated in a routine diagnostic laboratory for the detection of hepatitis C virus (HCV) RNA. The new system was compared with the corresponding microwell plate assay (AMPLICOR HCV Test). STUDY DESIGN: Routine clinical sera (350) from hemodialysis patients and patients with chronic HCV infection and interferon therapy were studied. If discrepant results were obtained, both assays were repeated (specimen preparation, amplification and detection); in addition, the HCV copy number was determined with the AMPLICOR HCV MONITOR Test. RESULTS: There was a correlation between the CA HCV Test and the AMPLICOR HCV Test in 341 of 350 specimens (97%). After resolution of 9 discrepant results, the CA HCV Test gave a sensitivity of 97.8% and a specificity of 99.4%. The most common reason for discrepant results was a low HCV RNA copy number. CONCLUSION: The CA system was found to be a labor-saving, fast and reliable instrument for the amplification and detection steps of a RT-PCR molecular assay for detection of HCV RNA.

Flaviviridae Infections↗

PubMed1997

Relative weight and mortality in U.S. blacks and whites: findings from representative national population samples.

PURPOSE: To examine the impact of relative weight on mortality in black and white men and women. METHODS: Two representative national populations samples were used: the NHANES-I Epidemiologic Follow-up Study (NHEFS), and the National Health Interview Survey (NHIS). The principal analysis focused on 13,242 participants in the NHEFS and 114,954 in the NHIS. Minimum mortality was estimated from both categorical analysis and a logistic model. RESULTS: Minimum mortality ranged from a body mass index (BMI) of 25 to 32 kg/m2. The model-estimated BMI of minimum mortality for NHEFS was 27.1 (24.8-29.4, 95% CI), 26.8 (24.7-28.9, 95% CI), 24.8 (23.8-25.9, 95% CI) and 24.3 (23.2-25.4, 95% CI); for black men, black women, white men and white women, respectively, whereas for NHIS the corresponding values were 30.2 (24.8-35.6, 95% CI) 26.4 (24.2-28.7, 95% CI), 27.1 (25.5-28.7, 95% CI), and 25.6 (24.2-27.0, 95% CI). In all groups the shape of the relative risk curve was virtually identical and a broad range of BMI values in the middle of the distribution was associated with low relative mortality risk. Averaging the results from both surveys, the observed BMI of minimum risk was 3.1 kg/m2 higher in black men and 1.5 kg/m2 higher in black women than in their white counterparts; when adjusted for covariates these differences were only of borderline statistical significance, however. CONCLUSIONS: Because of the wide range of BMI values associated with low risk, and the consistency of the point of the up-turn in risk, group specific definitions of optimal values do not appear to be warranted.

Adult↗

PubMed1997

Rapid detection of Mycoplasma pneumoniae by an assay based on PCR and probe hybridization in a nonradioactive microwell plate format.

A new molecular assay, based on a rapid DNA extraction protocol, PCR, and hybridization to a specific probe in a nonradioactive microwell plate format was used to detect Mycoplasma pneumoniae in bronchoalveolar fluid specimens. The sensitivity of the assay was determined to be 10 to 100 organisms with M. pneumoniae reference strains. Specificity testing with different bacteria capable of producing pneumonia showed no cross-reactivity. In a prospective study, bronchoalveolar lavage fluids obtained from patients with pneumonia were investigated with the PCR assay and compared to culture. Twelve positive samples were detected with the PCR assay. Seven of them were subsequently confirmed by culture. All patients with positive PCR results seroconverted. Application of the PCR assay described may lead to safe and early diagnosis of M. pneumoniae in patients with pneumonia.

Adolescent↗

PubMed1997

[Mechanism of protective action of Phyllanthus urinaria L. against injuries of liver cells].

It has been found out that the carbon tetrachloride (CCl4)-induced increase of serum glutamic-pyruvic transaminase (ALT) and elevation of MDA in liver of mice are significantly lowered by Phyllanthus urinaria in vivo, and the coincubation of isolated rat hepatocytes with Phyllanthus urinaria in vitro significantly inhibits CCl4-induced decrease of mobility of membrane of liver cells and increase of intracellular free Ca2+ ([Ca2+]i) concentrations of liver cells. These results suggest that the anti-lipid peroxidation effect and protective action of membrane of Phyllanthus urinaria may be related to its protective action against CCl4-induced liver injuries.

Alanine Transaminase↗

PubMed1997

[The preliminary study on WCMM machinable glass-ceramics].

The aim of this work was to investigate machinable glass-ceramics used as oral restoration material in K2O-MgO-Al2O3-SiO2-F glass system. By using of DTA, XRD and SEM investigation, the crystalline structure and characteristics were tested. The chemical composition of WCMM machinable glass-ceramics was defined by the following general formula: (K,Na)Mg3-3x Al2x (AlSi3) O10F2(0.5 < or = x < 0.7). The experimental results show that WCMM is an excellent oral restoration materials in the fabrication of crowns, inlayers and veneers.

Ceramics↗

PubMed1997

[The study on apatite castable glass-ceramics in composition and physicochemical properties].

The authors reported the result of the study of the glass formation range and physicochemical characteristics of apatite (APA) castable ceramics in the CaO-MgO-Al2O3-SiO2-P2O5 system. The relationship between its component and casting properties, the mechanical property and chemical stability was mainly discussed. The result showed that homogeneous glass could be formed in the experimental scope. This glass crystallized enamel-analogous apatite phase. It has improved mechanical property of parent glass, the bending strength was up to 165 MPa and possessed a fine chemical stability. This investigation could provide a new castable ceramics material for dental restoration.

Apatites↗

PubMed1997

[Analysis of the pyridinoline and deoxypyridinoline in urine by reversed-phase high performance liquid chromatography (RP-HPLC)].

A method for the simultaneous and rapid determination of pyridinoline and deoxypyridinoline in urine using RP-HPLC has been established. After hydrolysis for 18 hours at 107 degrees C in 6 mol/L HCl, the urine sample was prefractionated by partition chromatography using a column packed with cellulose CF1. The appropriate fractions were freeze-dried. The samples were analyzed by HPLC with a 5 microm Spherisorb C18 column, a mobile phase of MeOH/H2O containing 0.1% heptafluorobutyric acid at a rate of 1.2 mL/min and fluorescence detector monitoring at lambda(ex) 290 nm and lambda(em) 400 nm. The limit of a detection for PYD was 10 nmol/L and DPD 7 nmol/L. The recovery of PYD was 91.5% and that of DPD was 106.1%. Within day CV for the two compounds were 1.39% and 0.16% respectively and day-to-day CV 3.71% and 1.32% respectively.

Amino Acids↗

PubMed1997

Effect of aspirin on prostaglandin E2 and leukotriene B4 production in human colonic mucosa from cancer patients.

Results from epidemiological studies indicate that chronic administration of aspirin reduces the incidence of colon cancer. The mechanism that accounts for this reduction is not known, but it may be related to the decreased production of prostanoids that results from aspirin inhibition of cyclooxygenase. However, it is not known whether aspirin has a local effect on prostanoid production in the colonic mucosa and whether this effect is dose dependent. In this study, we determined the effect of oral administration of aspirin on the production of the prostanoid prostaglandin E2 (PGE2) in the intact human colonic mucosa. Inhibition of cyclooxygenase could result in an increased availability of arachidonic acid and a corresponding increase in production of other eicosanoids. To determine whether such an effect occurs, we also quantitated the concentration of leukotriene B4 (LTB4) in colonic mucosal samples. Mucosal samples were obtained during sigmoidoscopy from the colons of 17 subjects with a history of colonic cancer prior to and following 60 days of self-administration of 325 mg aspirin/day and again 60 days after administration of 650 mg aspirin/day. PGE2 and LTB4 concentrations were determined by enzyme immunoassay for tissue samples that were flash frozen after removal from the biopsy forceps and also in medium that was collected from tissue samples that were incubated for 4 h following removal from the subject. PGE2 concentrations were decreased significantly in samples collected after 60 days of consumption of 325 mg aspirin. An additional 60 days of consuming 650 mg aspirin/day did not result in a further significant decrease relative to that attained after consumption of 325 mg/day. Similar results were obtained using colonic explants, and the addition of aspirin to medium further reduced PGE2 production. LTB4 in tissue and medium was not significantly different in pre-versus post-aspirin samples, with the exception of an increased concentration in medium samples collected after consumption of 650 mg/day relative to pre-aspirin samples. The results indicate that aspirin affects eicosanoid production in the colonic mucosa of humans, but the effect is most likely restricted to products of the cyclooxygenase-dependent pathway. It appears that 325 mg of aspirin is sufficient to affect PGE2 production and that increasing the dosage to 650 mg daily provides an additional decrease in PGE2 synthesis. However, the higher dosage was associated with a considerable increase in complaints of gastric discomfort. Additional study is needed to establish whether doses less than 325 mg also provide a significant decrease in PGE2 production.

Adult↗

PubMed1997

[The crystallization feature of a castable apatite glass-ceramics].

The crystallization feature of a castable apatite glass-ceramics was studied by the means of DTA, XRD and SEM. The effect of chemical composition on the microsturcture of the glass-ceramics was discussed. The introduction of MgO and Al2O3 into the system has a substantial influence on the crystallization feature.

Apatites↗