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Biomedical subjects

Z Yuan

Publications and source records attributed to Z Yuan.

At least 145 records · Page 8Linked to original sources
PubMed1997

[Gene expression of thyrotropin receptor, thyroid peroxidase and thyroglobulin in autoimmune thyroid disease].

To investigate the expression of thyrotropin (TSH) receptor gene in autoimmune thyroid disease and the relationship with expression of thyroid peroxidase (TPO) and thyroglobulin (TG) genes, we examined TSH receptor, TPO and TG gene expression levels in 10 human thyroid tissues by Northern blot analysis, including 7 Graves disease (GD), 2 Hashimoto disease (HT), and 1 normal thyroid tissue. The expression levels of TSH-R gene and TG/TPO gene were different between GD group and HT group. In GD group, TSH-R gene expression was closely correlated to the expression of TPO gene (r = 0.882; P < 0.01) and TG gene (r = 0.723; P < 0.05). The gene expression levels in GD were higher than those in HT and control. In HT group, TPO, TG gene expression levels were relatively lower while TSH-R gene expression levels were still in normal range. The difference in gene expression is possibly related to the types of autoimmune antibodies and various dripping rates.

Adult↗
PubMed1997

[Determination of Keganmin tablet with multi-wavelength K-factor spectrophotometry].

The contents of phenacetin, aminopyrine and caffeine in Keganmin tablet were determined simultaneonsly with multiwavelength K -factor spectrophotometry. The result is accurate and the method is rapid. The average recoveries and relative standard deviations of the analysis for phenacetin, aminopyrine and caffeine were 99.91%, 0.41%; 100.1%, 0.29%; 100.1%, 0.56%, respectively.

Aminopyrine↗
PubMed1997

Racial disparity in the incidence and case-fatality of colorectal cancer: analysis of 329 United States counties.

In the United States, blacks have higher death rates from colon cancer than whites, and the survival disparity may be due in part to differences in screening programs and acute medical care in counties with a high concentration of blacks. We studied 148,947 Medicare beneficiaries with newly diagnosed colorectal cancer in 1989-1991 who resided in the 329 most populous counties in the United States to determine the relationship of race and county racial composition to cancer incidence and survival. Counties were divided into quartiles based on proportion of blacks in the population, and aggregate incidence and 2-year case-fatality rates were compared within and between quartiles. Within each quartile, the adjusted incidence rate for whites was consistently higher than that for blacks (P < 0.0001), and case-fatality rates were consistently lower among whites (P < 0.0001) for all but the quartile with the lowest proportion of blacks. Between quartiles, the incidence rates for both whites (P = 0.0001) and blacks (P = 0.008) decreased progressively, and case fatality rates increased progressively for both whites (P = 0.001) and blacks (P = 0.007) as the proportion of blacks increased. When counties were grouped into three different geographic areas, racial disparity in survival was observed in all regions. The variability between groups of counties in colon cancer incidence and mortality for both white and black patients may suggest differences at the county level in screening and treatment. However, consistent racial disparity within county quartiles may reflect persistent deficiencies in access to and quality of care for black patients.

Aged↗
PubMed1996

Site-directed mutagenesis of Cys324 and Cys331 in human cytosolic phospholipase A2: locus of action of thiol modification reagents leading to inactiviation of cPLA2.

Human cytosolic phospholipase A2 contains two cysteines, cyS324 and cyS331, chemical modification of which using thiol modifying reagents abolishes the activity of the enzyme [Li et al. (1994) Biochemistry 33, 8594-8603]. To verify the functional importance of the two cysteine residues, site-directed mutagenesis has been used to create six mutations at positions 324 and 331. The mutant enzymes include C324A, C331A, C324Q, C331Q, C324R, and C331S. Complete loss of activity is observed for C331Q, whereas the other mutants have retained varying degrees of activity. These results show that neither CyS324 nor CyS311 is catalytically essential for the enzyme activity. Further chemical modification studies of the mutant enzymes by thiol-specific reagents suggest that modification of Cys331 is responsible for the complete loss of the enzyme activity. The possible roles of Cys324 and Cys331 are discussed.

Amino Acid Sequence↗
PubMed1996

Combined flurbiprofen and cyclosporin-A does not attenuate bone loss and exaggerates renal impairment.

Cyclosporine (CsA) is a potent immunosuppressant that has revolutionized the success of organ transplantation. Flurbiprofen (FB), a propionic acid derivative NSAID, has been demonstrated in vivo to reduce osteoclast numbers in normal rats. The aim of this experiment was to determine whether addition of FB to CsA-treated rats could prevent the bone changes associated with CsA therapy. Forty-eight 10-12-week-old male Sprague-Dawley rats were randomized to receive, daily for 28 days: (1) CsA vehicle p.o. plus FB vehicle sc; (2) CsA (15 mg/kg) p.o. plus FB vehicle sc, (3) CsA vehicle p.o. plus FB (1.5 mg/kg) sc; and (4) CsA (15 mg/kg) p.o. plus FB (1.5 mg/kg) sc. Rats were weighed and venous blood sampled at baseline, 14 days, and 28 days for determination of glucose, Ca+2, BUN, creatinine, PTH, osteocalcin, and 1,25(OH)2 vitamin D. Tibiae were removed following killing, after double labeling for histomorphometry. Body mass was significantly lower than control in all rats receiving CsA on days 14 and 28 while blood glucose was only elevated in the CsA alone group. Day 28 BUN and creatinine were significantly elevated in the CsA group and the combination of CsA and FB revealed an exacerbation of this trend. Vitamin D and osteocalcin were consistently increased in the CsA and CsA/FB groups. Bone histomorphometry showed evidence of trabecular osteopenia in CsA and CsA/FB groups. CsA alone resulted in elevated bone turnover. FB was unable to prevent the trabecular bone loss induced by CsA therapy. This experiment indicates no role for FB as a therapeutic option in CsA-induced bone disease at the given doses and duration of treatment by virtue of its lack of bone sparing ability and adverse renal effects when the two drugs are administered concurrently.

Administration, Oral↗
PubMed1996

Abdominal and vaginal radical hysterectomy among U.S. women aged 65 years and older.

Unlike most European and Asian countries, radical vaginal hysterectomy (RVH) is not performed often in the United States, especially among older women. To examine the changes in RVH over the years, trends in hospital stay, hospital charges, and patient survival, we studied women aged 65 years and older undergoing RVH and compared them with patients receiving radical abdominal hysterectomy (RAH). During the study period there were a total of 288 RVH surgeries compared with 4,835 RAH surgeries. There were no significant changes in the number or proportion of RVH patients over 8 years (p = .50, trend test). On the average, RVH patients were significantly older and had shorter hospital stays. Among patients without cancer, there were no significant differences in the age, race, or survival of patients having either RVH or RAH. Similar results were obtained for patients with cancer.

Age Factors↗
PubMed1996

Selections from current literature: cholelithiasis, cholecystectomy and the risk of colorectal cancer.

The study by Ekbom et al. clearly demonstrates that, overall, there is no increased risk of colorectal cancer following cholecystectomy. However, it is noted that women have a slight increase in the risk of proximal colon cancer following cholecystectomy. The reasons for this finding remain unclear. However, since this finding has been consistent in several studies, it is probably not an artifact, but a true association that may warrant further investigation. It is possible that the association noted between cholecystectomy and colorectal cancer is due not to the cholecystectomy, but to the reason why cholecystectomies are performed, namely the presence of gallstones. The cholecystectomy itself may simply be a surrogate for cholelithiasis, which may be a true risk factor for colorectal cancer. Excess secondary bile acids may be carcinogenic or the factors which cause the formation of cholelithiasis may also increase the risk for developing colorectal cancer. An answer to the separate question of whether excessive laparoscopic cholecystectomies are being performed, or whether newer indications make the increased number of laparoscopic cholecystectomies appropriate, remain outstanding. This new procedure, despite being cheaper than the open cholecystectomy, has resulted in greater utilization of the world's dwindling health care resources. In conclusion, the decision to perform a cholecystectomy should be made only with consideration of the patient's current medical condition. There is no need to be concerned about any future increased risk of colorectal cancer following a cholecystectomy.

Aged↗
PubMed1996

Surgery for colorectal cancer: Race-related differences in rates and survival among Medicare beneficiaries.

This study examined surgery for colorectal cancer among Medicare beneficiaries 65 years of age or older with an initial diagnosis in 1987 (n = 81 579). Black patients were less likely than White to undergo surgical resection (68% vs 78%), even after age, comorbidity, and location and extent of tumor were controlled for. Among those who underwent resection, Black patients were more likely to die (a 2-year mortality rate of 40.0% vs 33.5% in White patients); this disparity also remained after confounders had been controlled. The disparities were similar in teaching and nonteaching hospitals and in private and public hospitals. These data may indicate racially based differences among Medicare beneficiaries in access to and quality of care for colorectal cancer.

Black or African American↗
PubMed1996

[Study of heterogeneity in DNA ploidy and its clinical-pathological significance in esophageal squamous cell carcinoma].

In order to investigate the intratumoral DNA ploid heterogeneity in esophageal squamous cell carcinoma and its significance, nuclear DNA ploidy of 80 cases of squamous cell carcinoma of the esophagus were determined for multiple samples obtained from the same tumor, using a flow cytometry (FCM) technique. The results showed that: (1) DNA indeces ranged from 7.7-1.74, and the incidence of DNA aneuploidy was 88.8% (71/80) in this series; (2) of 80 cases, (47.5% 38 cases) showed intratumoral heterogeneity in DNA ploidy (3) the heterogeneity in DNA ploidy was related to the extent of wall penetration by tumor, the incidnce of lymph node metastasis and patient's prognosis, not to histological grades and size of tumor. The results from this study indicated that DNA ploidy heterogeneity may be a exact indicator in reflecting the biological characteristics of tumor and patient's prognosis than DNA aneuploidy from single site sampling.

Adult↗
PubMed1995

Sensitive assay for measuring amoxicillin in human plasma and middle ear fluid using solid-phase extraction and reversed-phase high-performance liquid chromatography.

We developed a sensitive assay to measure amoxicillin in human plasma and middle ear fluid (MEF) using solid-phase extraction and reversed-phase HPLC. Amoxicillin and cefadroxil, the internal standard, were extracted from 50-200 microliters of sample with Bond Elut C18 cartridges. The extract was analyzed on a 15 cm x 2 mm, 5 micron Keystone MOS Hypersil-1 (C8) column with UV detection at 210 nm. The mobile phase was 6% acetonitrile in 5 mM phosphate buffer (pH = 6.5) and 5 mM tetrabutylammonium. The average absolute recovery of amoxicillin and cefadroxil were 91.2 +/- 16.6% and 91.0 +/- 6.8%, respectively. The limit of quantitation was 0.125 microgram/ml with 200 microliters sample size. The linear range was from 0.125 to 35.0 micrograms/ml with correlation coefficients greater than 0.999. These analytic conditions produced a highly sensitive amoxicillin assay in human body fluids without derivatization.

Acetonitriles↗
PubMed1995

Stimulation of human monocytes with macrophage colony-stimulating factor induces a Grb2-mediated association of the focal adhesion kinase pp125FAK and dynamin.

Macrophage colony-stimulating factor (M-CSF) is required for the growth and differentiation of mononuclear phagocytes. In the present studies using human monocytes, we show that M-CSF induces interaction of the Grb2 adaptor protein with the focal adhesion kinase pp125FAK. The results demonstrate that tyrosine-phosphorylated pp125FAK directly interacts with the SH2 domain of Grb2. The findings indicate that a pYENV site at Tyr-925 in pp125FAK is responsible for this interaction. We also demonstrate that the Grb2-FAK complex associates with the GTPase dynamin. Dynamin interacts with the SH3 domains of Grb2 and exhibits M-CSF-dependent tyrosine phosphorylation in association with pp125FAK. These findings suggest that M-CSF-induced signaling involves independent Grb2-mediated pathways, one leading to Ras activation and another involving pp125FAK and a GTPase implicated in receptor internalization.

Adaptor Proteins, Signal Transducing↗
PubMed1995

A national population-based study of incidence of colorectal cancer and age. Implications for screening in older Americans.

BACKGROUND: Population-based screening programs with flexible sigmoidoscopy have been advocated as a means to reduce the death rate from colorectal cancer. Because other studies have suggested a greater prevalence of lesions inaccessible to sigmoidoscopy in older patients, the expected yield of this procedure may differ in these subgroups. METHODS: A 100% sample of Medicare beneficiaries 65 years or older with a first known diagnosis of colorectal cancer in 1987 was studied. Tumor site was divided into rectum, distal colon (distal to splenic flexure) and proximal colon. The analysis was also stratified by sex, race, and presence or absence metastatic disease, and incidence rates at each site by 5-year age group were calculated. RESULTS: Among the 75,266 patients studied, the incidence of colorectal cancer increased from 1.59 patients/1000 in patients age 65-69 years to 3.87 patients/1000 in patients age 85 years and older. Although the incidence rates at all three sites increased, the increment was greatest for proximal tumors. The incidence trends with age also persisted in an analysis of only metastatic lesions. Moreover, incidence rates were consistently higher in men than in women and higher in whites than in blacks at all sites, though the age-related increase in incidence was consistent among all four groups. CONCLUSIONS: The proportion of tumors beyond the reach of sigmoidoscopy increased with age, as did the actual incidence of accessible lesions. These patterns were also consistent in subgroup analyses. As the age-related increase in incidence was observed for metastatic tumors at all sites in the colon, age-related differences in screening and diagnostic evaluation alone do not adequately explain the findings. These data underscore the need for further studies of the relative benefits of cancer screening and pathogenic factors in tumor development in different subgroups of the older population.

Age Factors↗
PubMed1995

Remobilization partially restored the bone mass in a non-growing cancellous bone site following long term immobilization.

There is no report in the rat of the effects of remobilization (RM) in an adult bone site. The aim of this study was to determine whether complete recovery from IM-induced bone loss will occur in a non-growing bone site, the distal tibia. Seventy-five 6-month-old virgin Sprague-Dawley female rats were used in this study. Their hindlimbs were immobilized against the abdomen with bandages for 18 weeks, then remobilized for 2, 10 or 20 weeks. Distal tibial sections were analyzed in the former epiphysis, 0.3 mm proximal from the calcified cartilage, and in trabecular bone of the former metaphysis between 0.3 mm and 1.92 mm proximal to the former epiphysis. A significant bone loss occurred in both former epiphyseal and metaphyseal trabeculae at 18 weeks after IM. The lost bone was partially recovered at 10 weeks of RM, but the bone mass was still lower than in aging controls by the end of the study. The partial recovery was characterized by decreasing former epiphyseal bone porosity and thickening of former metaphyseal trabeculae with no effect on trabecular number. We concluded that both distal tibia regions only partially recovered, during 20 weeks of RM from the long time IM.

Animals↗
PubMed1995

Adequacy of national mortality data for internal hospital use: a case study.

OBJECTIVE: The study investigated the value of using national or regional data bases to examine care in a specific hospital. DATA SOURCES: The following data sources were included: (1) the results of the 1992 HCFA analysis of the index hospital for patients hospitalized in fiscal year 1990; (2) the 1989 Medicare Provider Analysis and Review (MEDPAR) file; and (3) clinical information from bypass surgery patients in Wisconsin and from the index hospital. PRINCIPAL FINDINGS: The assessment of the mortality rates in the index hospital for all conditions combined and for CABG patients differed depending on what data base was used and how the data were analysed. The national data were most useful in establishing that the coding practices for all patients and the mortality rate for intra-aortic balloon patients differed between the index hospital and other hospitals. The regional clinical data base for bypass surgery patients was used to establish that the high mortality rates for intra-aortic balloon patients were due to patient selection. CONCLUSIONS: National claims data must be analysed carefully before applying results to an individual hospital. Even a careful analysis is more for raising questions about care at a specific hospital rather than for reaching definitive conclusions.

Aged↗
PubMed1995

Cerebral arterial aneurysm formation and rupture in 20,767 elderly patients: hypertension and other risk factors.

Cerebral arterial aneurysms are common in the general population and their rupture is a catastrophic event. Considerable uncertainty remains concerning the conditions that predispose individuals to aneurysm formation or rupture. The role of systemic hypertension in aneurysm formation and rupture has been especially controversial. Demographic variables have rarely been addressed because of the small sample sizes in previous studies. The authors describe the demographics and prevalence of hypertension in 20,767 Medicare patients with an unruptured aneurysm and compared these to a random sample of the hospitalized Medicare population. The prevalence of hypertension in patients with unruptured aneurysms was 43.2% compared with 34.4% in the random sample. Patients who survived their initial hospitalization were separated into two groups: those with an unruptured cerebral aneurysm as the primary diagnosis and those with an unruptured cerebral aneurysm as a secondary diagnosis. Follow-up data for 18,119 patients were examined to determine the risk of subarachnoid hemorrhage (SAH) associated with age, gender, race, hypertension, insulin-dependent diabetes mellitus, and surgical treatment. For patients with an unruptured cerebral aneurysm as the primary diagnosis, hypertension was found to be a significant risk factor for future SAH (risk ratio: 1.46, 95% confidence interval (CI): 1.01-2.11), whereas surgical treatment (risk ratio: 0.29, 95% CI: 0.09-0.97) had a significant protective effect. Advancing age had a small but significant protective effect in both groups. Elderly patients identified with unruptured aneurysms are more likely to have coexisting hypertension than the general hospitalized population. In elderly patients hospitalized with an unruptured cerebral aneurysm as their primary diagnosis, hypertension is a risk factor for subsequent SAH, whereas surgical treatment is a protective factor against SAH.

Age Factors↗
PubMed1995

[The reconstruction of facial burn and deformity from burn scar].

Thirty-seven patients with facial full-deep burn and burn scar contructure were treated in our department. The operation included transplantation, of whole piece of full thickness skin (3 patients), transplantation of whole piece of full thickness skin with subdermal vascular rete a (1), transplantation of improved whole piece of full thickness skin (26), and separated transplantation of large piece of partial thickness skin (7). Follow-up from 3 to 15 years showed that the facial skin of whole piece of full thickness skin was soft, smooth, and had natural facial expression. The facial skin of separated transplantation had slight scar and pigmentation. The improved whole piece of full thickness skin was recommendable for avoiding the secondary ectropion of eyelid and lip.

Adolescent↗
PubMed1995

[Preliminary study on the anti-tubercular effect of Ottelia alismoides (L.) Pers].

In clinical trials, the extract of Ottelia alismoides cured two cases of bilateral tuberculosis of cervical lymph gland within 3 months. The result of drug sensitive test showed that water extract of this herb could kill or inhibit human tubercular bacteria effectively, which suggests that Ottelia alismoides is a promising medicinal herb with anti-tubercular effect.

Antitubercular Agents↗