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Biomedical subjects

Y Liao

Publications and source records attributed to Y Liao.

At least 163 records · Page 9Linked to original sources
PubMed1992

Structure of a tricyclic subunit of manzamine A.

(4a alpha,7a beta,10a beta)-2-Benzyl-1,2,3,4,4a,7,7a,8,9,10-decahydro-8,8- dimethylpyrrolo[2,3-i]isoquinolinium iodide, C20H29N2+.I-, M(r) = 424.37, monoclinic, P2(1)/n, a = 9.441 (4), b = 10.378 (4), c = 20.023 (9) A, beta = 91.56 (3) degrees, V = 1961 (1) A3, Z = 4, Dx = 1.44 g cm-3 (188 K), lambda(Mo K alpha) = 0.7107 A, mu = 16.16 cm-1, F(000) = 864, T = 188 K, R = 0.0288 for 3070 reflections [Fo greater than or equal to 4 sigma(Fo)]. The crystal structure determination was undertaken in order to establish the configuration around C10a. The rings of the isoquinoline group are trans, with the pyrrole moiety cis fused. The A ring is in the chair conformation, while the cyclohexene ring, B, is in the boat conformation owing to the cis fusion of the five-membered pyrrole ring. The pyrrole ring, C, assumes the half-chair conformation. The C-N bonds of the quaternary N atom, N8, are longer than those of the tertiary N atom, N2 [1.517 (2) for N8 and 1.463 (2) A for N2].

Carbazoles↗
PubMed1992

Changes in pulmonary hemodynamics with aging in a predominantly hypertensive population.

The impact of aging on pulmonary hemodynamics was investigated in 322 patients who underwent right- and left-sided cardiac catheterization and echocardiographic examination, and were free of coronary disease, impaired left ventricular systolic function and left ventricular dilatation. Most of the patients were black (83%) and hypertensive (78%). Mean pulmonary artery pressures increased progressively with age: 16.7 +/- 4.6, 17.9 +/- 6.4 and 20.6 +/- 8.0 mm Hg for those aged less than 45 (n = 50), 45 to 64 (n = 238) and greater than or equal to 65 years (n = 34), respectively (p = 0.020). Pulmonary vascular resistance was 99 +/- 42, 116 +/- 62 and 160 +/- 68 dynes s cm-5, and the ratio of pulmonary to systemic vascular resistance was 78, 80 and 105%, respectively, for the 3 age groups (p less than 0.001). Along with these changes, a decrease in cardiac output and an increase in systolic blood pressure and systemic vascular resistance with age were noted. The effect of age on mean pulmonary artery pressure and pulmonary vascular resistance was statistically significant after adjustment for gender, smoking status, body weight, left ventricular hypertrophy, systolic blood pressure and systemic vascular resistance. Consideration should be given to age-related changes in the pulmonary circulation when defining physiologically normal values.

Aged↗
PubMed1992

Survival of heart failure patients with preserved versus impaired systolic function: the prognostic implication of blood pressure.

The impact of impaired versus preserved systolic function on survival of patients with heart failure was investigated in 78 patients with decompensated heart failure. Patients were classified on the basis of their left ventricular systolic performance, as defined by fractional shortening (FS); group I (n = 56) had impaired systolic function (FS less than 24%) and group II (n = 22) had preserved systolic function (FS greater than or equal to 24%). Mean ejection fraction was 15 +/- 5% and 40 +/- 13% for these groups, respectively. By the end of 48 months, 36 patients in group I had died compared with only 22 patients in group II (p less than 0.05). Both systolic and diastolic blood pressure were significantly lower in the deceased patients compared with the survivors in group I (p less than 0.05). There was a trend for an opposite direction in the relationship of blood pressure to mortality in group II. We conclude that the prognosis of patients with heart failure and preserved systolic function is more favorable than that of those with impaired function, and that blood pressure may have a differential prognostic meaning in the two groups.

Blood Pressure↗
PubMed1992

Serum lipids and their correlates in Chinese urban and rural populations of Beijing and Guangzhou. PRC-USA Cardiovascular and Cardiopulmonary Epidemiology Research Group.

In 1983 and 1984, surveys were conducted in four Chinese population samples, urban and rural for both Beijing and Guangzhou, as part of PRC-USA collaborative research in cardiovascular and cardiopulmonary epidemiology. Serum total cholesterol (TC), HDL-cholesterol (HDL-C), and triglycerides (TG) were measured in 4280 men and 4695 women aged 35-54 years, in laboratories standardized by the US Centers for Disease Control. Age-adjusted mean serum TC was higher in urban than rural samples and generally higher in Beijing than Guangzhou, ranging from 155 mg/dL for Guangzhou rural women to 187 mg/dl for Guangzhou urban women. Group mean values of HDL-C varied from 48 to 59 mg/dl, higher in Beijing than Guangzhou, and higher in women than men. TC/HDL-C ratio ranged from 3.05 to 3.82. Serum TG values were higher for Beijing than Guangzhou; the lowest group mean values of 78 mg/dl and 75 mg/dl were in rural Guangzhou men and women. Mean body mass index (BMI) was uniformly low, ranging from 20 kg/m2 for rural Guangzhou to 24 kg/m2 for urban Beijing. Multiple regression analyses showed that BMI was positively and independently related to serum TC, LDL-C, TG, and TC/HDL-C, and inversely related to HDL-C. Smoking was positively related in both sexes to TG and TC/HDL-C, and inversely related to HDL-C. Smoking was also positively related to TC and LDL-C in men. In men, alcohol was positively related to TC and HDL-C, and was inversely related to TG and TC/HDL-C. Heavy manual work was inversely related to TC, LDL-C, and TC/HDL-C in men, but not related to lipids in women. Thus, for these Chinese population samples, despite their lower serum TC and BMI, the correlates of serum lipids are similar to those in western populations. These variables accounted for only part of the observed urban-rural and north-south differences in serum lipids among these Chinese population samples. The significance of the relatively low serum TC and TG and high HDL-C in relation to low cardiovascular disease in Chinese populations is the object of further investigation in follow-up studies.

Adult↗
PubMed1992

[Study on casting precision of plat castable ceramic crowns].

The plat castable ceramic crown was made with investment material prepared in our college with our own casting technique by a Chinese-made casting machine. The accuracy and fitness of the crown were studied and appraised. Results show that the margin of fitness is 46 microns and that the cement film thickness of the dies in the spacer material group is 65.13 microns. Hence the results are satisfactory. The Plat castable ceramic crown might be used in clinical dentistry.

Crowns↗
PubMed1992

Atrial natriuretic factor and renin synthesized in cultured aortic smooth muscle cells of rats.

This study was designed to determine whether or not atrial natriuretic factor (ANF) is present in the vascular walls and to observe the differences in ANF between control (WKY) and stroke-prone spontaneously hypertensive rats (SHRsp). It was found that ANF is indeed present in the vascular wall of the distal aorta. HPLC analysis of the extracts from cultured aortic smooth muscle cells (ASMC) and medium revealed that intracellular ANF was mainly in the form of ANF(1-126), at levels of 0.82 +/- 0.03 (SHRsp) and 1.04 +/- 0.10 ng/10(6) cells (WKY), while the major form in the medium was ANF(99-126), at levels of 0.40 +/- 0.06 and 0.60 +/- 0.06 ng/10(6) cells, respectively. Both forms were present in smaller amounts in SHRsp than in WKY rats. On the contrary, both renin activity and angiotensin I concentrations in SHRsp cells were significantly higher than those in the WKY controls. In addition, immunocytochemistry showed positive ANF staining in cultured ASMC of both strains. The results suggest that ANF can be synthesized and secreted by cultured ASMC from rats.

Animals↗
PubMed1990

[An observation of the anticancer activity of mitoxantrone hydrochloride injection].

Experimental results of anticancer activity of DHAQ.HCl are reported in this paper. It was discovered that DHAQ.HCl, mitoxantrone hydrochloride, had an obvious anticancer effect on the experimental tumor strains:Ehrlich ascites cancer, Sarcoma-180, Leukemia P388, etc., and that it was more effective to Leukemia P388 than to other strains. The anticancer activity of DHAQ.HCl was better than DHAQ (P less than 0.05). No side effect was observed on the local sites (s.c.) of tumor planted or drug injected. And also a good anticancer effect was observed on the sites of tumor planted by local injection. It is suggested that this observation can provide some information on the choice of routes of administration of this drug clinically.

Animals↗
PubMed1987

Cardiovascular responses to exercise of participants in a trial on the primary prevention of hypertension.

The Chicago study on the Primary Prevention of Hypertension (PPH) is a long-term, randomized controlled trial to test the ability of nutritional-hygienic non-pharmacological methods to prevent high blood pressure in hypertension-prone persons aged 30-44 years at entry. In order to assess the effects of this programme on cardiovascular responses to exercise, graded submaximal treadmill exercise tests were done serially at baseline and during the trial. Eighty-five participants (48 intervention, 37 control) successfully finished baseline and 2- or 3-year follow-up tests. The exercise maximal double product (DP) [systolic blood pressure (SBP) X heart rate/100] was significantly lower for both groups at 2-3 years compared with baseline, and this reduction was greater for the intervention than for the control group (-27.1 versus -15.5; P = 0.055). Similarly, improvement in maximal increase in DP (maximal DP minus standing DP) was greater for the intervention than the control group (-22.1 versus -9.9, respectively; P = 0.068). The lowest DP during the 6-min recovery period and the debt DP (lowest recovery DP minus standing DP) fell significantly at 2-3 years compared with baseline in the intervention but not in the control group (-12.7 versus -4.8; P = 0.017 for the first index, and -7.7 versus +0.9; P = 0.029 for the second). These interim data from this trial indicate that its intervention procedures favourably influenced cardiovascular responses to graded submaximal exercise.

Adult↗
PubMed1987

Sex differential in the relationship of electrocardiographic ST-T abnormalities to risk of coronary death: 11.5 year follow-up findings of the Chicago Heart Association Detection Project in Industry.

The independent contributions of ST segment depression and/or T wave abnormality (ST-T abnormalities) on the baseline resting electrocardiogram to risk of 11.5 year coronary heart disease (CHD) mortality were explored among 9203 white men and 7818 white women who were 40 to 64 years old and without definite CHD at entry in the Chicago Heart Association Detection Project in Industry. At baseline, prevalence rates of ST-T abnormalities were age related for both sexes, and at every age the rate was higher in women than men (age-adjusted prevalence rates 12.3% and 8.1%, respectively). Univariate analysis showed that ST-T abnormalities were associated with significantly increased risk of death from CHD for both men and women. However, men with ST-T abnormalities had much greater age-adjusted and multiple risk factor-adjusted absolute excess risk and relative risk than women with such electrocardiographic abnormalities. When baseline age, diastolic pressure, serum cholesterol, cigarettes/day, history of diabetes, and baseline use of antihypertensive medication were included in the multivariate analysis, ST-T abnormalities remained significantly related to death from CHD in men but not women. The interaction term between sex and ST-T abnormalities was at a borderline level of statistical significance by Cox regression analysis. In conclusion, ST-T abnormalities indicate an increased risk of subsequent death from CHD independent of major coronary risk factors for middle-aged U.S. men, but this is not clearly so for women.

Adult↗
PubMed1987

Reoperation in the treatment of recurrent intracranial malignant gliomas.

Fifty-five consecutive patients with recurrent intracranial malignant gliomas were reoperated at Memorial Sloan-Kettering Cancer Center from 1972 to 1983. The patients were 10 to 70 years old (median, 48 years). Thirty-five patients (64%) had glioblastoma multiforme, and 20 (36%) had anaplastic astrocytoma. The median interval between the first operation and reoperation was 43 weeks. The Karnofsky rating before reoperation ranged from 40 to 90 (median, 70). Eleven patients (20%) had more than one reoperation. The mortality rate was 1.4% per procedure, and the morbidity rate was 16% per procedure. After reoperation, 41 patients (75%) had chemotherapy and/or radiation therapy. The median survival for all patients was 92 weeks. The median survival after reoperation was 36 weeks. Patients with Karnofsky ratings of greater than or equal to 70, with anaplastic astrocytomas, or in whom gross total removal of the tumor was undertaken lived longer than their respective counterparts (P less than 0.05). Prereoperation Karnofsky rating and extent of surgical resection were the most important independent factors related to survival after reoperation according to multivariate analysis (P less than 0.01 and P less than 0.05, respectively). Twenty-five patients (45%) had improved Karnofsky ratings after reoperation, and the 32 patients (58%) who were independent after reoperation were able to stay so for more than 6 months of their survival time (median value). Reoperation is feasible and can be accomplished with acceptable mortality and morbidity. When intracranial malignant gliomas recur, the combined use of reoperation and adjuvant therapy prolongs good quality life.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Obesity modifies the relationship between ambulatory blood pressure and natriuresis in children.

BACKGROUND: The objective in the present study was to evaluate if obesity beginning in the first two decades of life influences the relationship between ambulatory blood pressure and urinary sodium excretion. DESIGN AND METHODS: Eighty-five obese and 88 non-obese children aged 3-19 years were included in the study. For each subject, a 24h ambulatory blood pressure monitoring and a complete urine collection were simultaneously performed according to the protocols designed. The averages of ambulatory blood pressure and of the urinary excretion rates for sodium, potassium and creatinine were calculated separately for 24-h, awake and sleep periods as defined by a mini-diary. RESULTS: Weight and sodium excretion are directly associated with systolic blood pressure; however, the relationship between blood pressure and sodium excretion seems to be modified in obese children as compared to controls. The interaction between sodium excretion and weight was negative indicating that the rate of change of systolic blood pressure by sodium unit is smaller for the obese than for the non-obese, even though at the same urinary sodium excretion level the obese children had higher ambulatory systolic blood pressure. CONCLUSIONS: Obesity during the first two decades of life seems to restrict sodium excretion, leading to higher blood pressure values. The capacity to excrete sodium seems to be heterogeneous, the lowest capacity being at the highest blood pressure values. Subsets of the obese, those with the lowest ability to excrete sodium, may be further protected by low sodium intake in order to prevent a rise in blood pressure.

Adolescent↗
PubMedDate not supplied

Possible cytotoxic effect of the expression of a connexin 43-LacZ fusion gene in cells of the vascular wall.

Connexin 43 (Cx43) gap junctions are hypothesized to play a key role in many aspects of vascular function. In an effort to evaluate the importance of connexins in vascular function we took advantage of the fact that a Cx43-LacZ fusion protein has been reported to effectively reduce dye transfer in NIH 3T3 fibroblasts by acting as a dominant negative construct. We explored the use of this dominant negative construct in cultured vascular smooth muscle (VSM) cells and in transgenic mice. We examined the viability of cultured VSM cells expressing the Cx43-LacZ fusion protein under the control of a cytomegalovirus promoter. We also selectively expressed the dominant negative construct in the endothelial cells of transgenic mice under the control of a Tie 2 promoter. Transient transfection of cultured VSM cells led to good initial expression of the Cx43-LacZ fusion protein as evidenced by X-gal staining. Following 10 days of G418 selection, 300 cell clones were examined. None expressed the fusion protein, based on X-gal staining and Western blot analysis, but all contained the transgene, based on PCR analysis. The fusion protein was expressed in a few isolated cells, suggesting that cell division was inhibited by the fusion protein. In agreement with this finding was the fact that expression of the Cx43-LacZ fusion protein was not observed in any of seven Tie 2-Cx43-LacZ transgenic mouse lines. Moreover, a very low yield of mice carrying the transgene was observed (7/136; 5.1%). Analysis of 65 embryos at embryonic day 11.5 showed similar results. These data strongly suggest that the expression of the Cx43-LacZ fusion protein prevents the formation of both stable clones and transgenic animals. This may be due to a cytotoxic effect of the dominant negative construct or to the fact that successful cell propagation is not possible if gap junctional transmission is completely blocked.

Animals↗
PubMedDate not supplied

Modulation of apoptosis, tumorigenesity and metastatic potential with antisense H-ras oligodeoxynucleotides in a high metastatic tumor model of hepatoma: LCI-D20.

BACKGROUND/AIMS: To investigate the effect of antisense H-ras DNA on tumorigenesity, apoptosis and metastasis of a high metastatic tumor model of human hepatocellular carcinoma in nude mice LCI-D20. METHODOLOGY: LCI-D20 cells in primary culture were treated with 10 microns/L antisense oligodeoxynucleotide (ODN) drugs in vitro. 1.5 x 10(6) LCI-D20 cells with or without pretreatment were inoculated into each elevated subcutaneous (s.c.) flap in 14 nude mice, 6 animals for antisense H-ras oligodeoxynucleotide treated cells, 4 for H-ras non-specific antisense oligodeoxynucleotide treated cells, and the rest 4 for cells without pretreatment. RESULTS: In in vitro cell culture study, 5-day continuous suppression of H-ras expression by antisense H-ras oligodeoxynucleotide resulted in significant inhibition of the proliferation of LCI-D20 cells (t = 31.529, P < 0.01). In situ end-labeling detection showed that apoptotic cell death was significantly increased in cells with 5-day treatment of antisense H-ras oligodeoxynucleotide (34.0 +/- 4.5%) in comparing with cells without treatment (2.5 +/- 1.2%, t = 13.434, P < 0.01) or treated with non-specific antisense oligodeoxynucleotide (4.8 +/- 1.4%, t = 12.453, P < 0.01) at the corresponding time. In the in vivo experiment, at week 6, no palpable tumor could be found in 50% (3/6) of animals receiving cells with pretreatment of antisense H-ras oligodeoxynucleotide, while 100% (4/4, 4/4) of animals in the 2 control groups developed palpable tumors. Tumor growth in antisense H-ras treated animals was significantly retarded in comparison with that of the untreated (t = 3.509, P < 0.01) or non-specific antisense oligodeoxynucleotide treated animals (t = 3.452, P < 0.01). 75% to 100% of animals in the 2 control groups developed lung metastases, while in antisense H-ras treated animals lung metastasis foci could not be found by random serial section and microscopy (u = 2.536, P < 0.01; u = 3.162, P < 0.01, respectively). CONCLUSIONS: Specific inhibition of H-ras expression by antisense H-ras oligodeoxynucleotides could not only induce apoptotic cell death, inhibit the growth rate of LCI-D20 cells in vitro and in vivo, but also alter in vivo tumorigenesity and metastatic potential of LCI-D20 cells.

Animals↗