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Biomedical subjects

M Wei

Publications and source records attributed to M Wei.

At least 73 records · Page 4Linked to original sources
PubMed1999

Do Mexican Americans really have low rates of cardiovascular disease?

In this article we challenge the conclusion made from vital statistics that Hispanic Americans have lower all-cause and cardiovascular disease (CVD) mortality than non-Hispanic whites. There is reason to believe that vital statistics underascertain minority, and in particular Hispanic, deaths. Cohort studies minimize many of these limitations. In the San Antonio Heart Study risk factor distributions predicted higher all-cause and CVD mortality among Mexican Americans than among non-Hispanic whites. Follow-up of the cohort confirmed a mortality ratio of 1.38 for all-cause and 1.30 for CVD mortality for Mexican Americans vs non-Hispanic whites. This excess risk was confined to U.S.-born Mexican Americans, since immigrants from Mexico had very low mortality despite low socioeconomic status. We attribute this latter finding to a "healthy migrant effect."

Cardiovascular Diseases↗
PubMed1999

LD-IgG, IgA, IgM complex in a postburn patient.

A 4-year-old Chinese boy was admitted to our hospital with burns over 25% of his body. He had an extremely high LD activity (1743 U/l). LD isoenzyme analysis showed an abnormal band cathodic to LD-5. It was demonstrated by counter immunoelectrophoresis that the extra band was a complex of LD with IgG, IgA and IgM. Because LD-Ig complex is extremely rare in patients with burns, the clinical significance of this substance in blood remains unclarified.

Burns↗
PubMed1999

Interfacial bond strength of electrophoretically deposited hydroxyapatite coatings on metals.

Hydroxyapatite (HAp) coatings were deposited onto substrates of metal biomaterials (Ti, Ti6Al4V, and 316L stainless steel) by electrophoretic deposition (EPD). Only ultra-high surface area HAp powder, prepared by the metathesis method 10Ca(NO3)2 + 6(NH4)2HPO4 + 8NH4OH), could produce dense coatings when sintered at 875-1000degreesC. Single EPD coatings cracked during sintering owing to the 15-18% sintering shrinkage, but the HAp did not decompose. The use of dual coatings (coat, sinter, coat, sinter) resolved the cracking problem. Scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) inspection revealed that the second coating filled in the "valleys" in the cracks of the first coating. The interfacial shear strength of the dual coatings was found, by ASTM F1044-87, to be approximately 12 MPa on a titanium substrate and approximately 22 MPa on 316L stainless steel, comparing quite favorably with the 34 MPa benchmark (the shear strength of bovine cortical bone was found to be 34 MPa). Stainless steel gave the better result since -316L (20.5 microm mK(-1)) > alpha-HAp (approximately 14 microm mK(-1)), resulting in residual compressive stresses in the coating, whereas alpha-titanium (approximately 10.3 microm mK(-1)) < alpha-HAp, resulting in residual tensile stresses in the coating.

Journal Article↗
PubMed1999

Urinary bladder carcinogenicity of dimethylarsinic acid in male F344 rats.

The present study was conducted to determine the carcinogenicity of dimethylarsinic acid (DMA) administered to male F344 rats in a 2 year bioassay. A total of 144 rats (10 weeks old at the start) were divided into four groups of 36 rats each. Groups 1-4 received DMA (purity 100%) at concentrations of 200, 50, 12.5 and 0 p.p.m. in the drinking water, respectively, for 104 weeks. From weeks 97 to 104, urinary bladder tumors were observed in 12 of 31, eight of 31 and none of 33 in groups 1-3, respectively. No bladder tumors were observed in group 4. The present study demonstrated that long-term p. o. administration of DMA induced urinary bladder carcinomas in male F344 rats. Therefore, the results indicate that DMA is carcinogenic for the rat urinary bladder, which may be related to the human carcinogenicity of arsenicals.

Administration, Oral↗
PubMed1999

[The clinical significance of preserving superior epigastric vessels in Cohen incision].

OBJECTIVE: To study the clinical significance of preserving epigastric vessels in Cohen incision. METHODS: 42 cases of pregnant women were performed cesarean section using Cohen incision. One side vessel of incision was preserved, the other side was cut off. By self control comparison, skin temperature of two sides incision has been taken by CET (computer electric infrared thermograph) on the third day post operation. The thinkness of scar was measured with vernier calipers on the 40th day post operation. RESULTS: The skin temperature difference between both sides of incision was (0.098 +/- 0.088) degree C. On the cut side the skin temperature was higher than that of the other side (P < 0.01). The scar thickness of cut side was (3.61 +/- 0.61) mm, the other side was (3.10 +/- 0.68) mm. The difference was significant (P < 0.01). CONCLUSION: The inflammatory reaction and formation of scar can be decreased by means of preserving superior epigastric vessels in Cohen incision.

Cesarean Section↗
PubMed1999

[Establishment of the animal models of mandibular distraction osteogenesis].

OBJECTIVE: To establish the animal models of mandibular distraction osteogenesis in rabbits and study its osteogenetic mechanism. METHODS: The right mandibles just anterior to the first molars of 12 rabbits were performed osteotomies, and the mandibles were positioned with distractors. The left mandibles were control group without operation. After 1 week, the distractors were stretched 0.9 mm every day for 10 days progressively. One day, 2, 4, 8 weeks after distraction, the mandibles were studied with gross measurement, X-ray, and histological examination. RESULTS: The right mandible were lengthened 8.3 mm on average without bone nonunion and deformity healing. It was observed that the gaps between the distracted bone edges were first occupied by fibrous tissue. Two weeks after distraction, it was found that the gaps were bridged by callus in X-ray, the new bone and the normal bone could not be differentiated clearly after 8 weeks. In histological sections, there were collagen bundles in early distraction, then those collagen bundles were calcificated and become trabeculaes. No Cartilage was found during distraction. CONCLUSION: It suggests that the rabbit mandible can be lengthened by distraction osteogenesis, and the new bone is formed by intramembranous ossification.

Animals↗
PubMed1999

[Expression of vascular endothelial growth factor and tumor angiogenesis correlates with biological behaviors of nasopharyngeal carcinoma].

OBJECTIVE: To study the correlation between tumor angiogenesis and biological behaviors of nasopharyngeal carcinoma(NPC). METHOD: Angiogenesis was assessed by the microvessel dinsity(MVD) and expression of vascular endothelial growth factor(VEGF) was detected using immunohistochemical S-P method. Paraffin-embedded specimens from 65 patients with NPC and 15 with benign nasopharyngeal tumors, 15 with tumor-free nasopharyngeal mucosac were detected. RESULT: Expressions of VEGF and MVD in NPC group were higher than that of nonmetastic carcinoma group. The relationship between expressions of VEGF and MVD and the clinical staging present statistic significance. CONCLUSION: MVD and expression of VEGF are highly correlated with biological behaviors of NPC, which may serve as a parameter for determining tumor biological metastatic potential and prognosis. Angiogenesis inhibitors might be helpful in preventing NPC from metastasis.

Adult↗
PubMed1999

[Design of CXLY-II low frequency magnetic fields pulse generator].

An experimental device, low frequency magnetic fields pulse generator, has been designed and accomplished in our department. It can provide low frequency magnetic fields pulse with the intensity from 150mT to 800mT and the frequency from 0 to 100Hz. This device is easy to operate and performs reliably. It can stably work for a long time and has been successful used in the experiment of magnetic biological effect.

Electromagnetic Phenomena↗
PubMed1999

Establishment of immunoglobulin M(IgM)-immunosorbent agglutination assay (ISAGA) for diagnosis of toxoplasmosis.

AIM: To establish an immunosorbent agglutination assay (ISAGA) for detection of IgM antibodies against Toxoplasma gondii. METHODS: In the ISAGA, wells of microtiter plates were coated with anti-human IgM antibodies and sealed with 1% bovine serum albumin. After the test sera were added and incubated, the plates were washed, T. gondii tachyzoite antigen suspension was added, and incubated overnight at 37 degrees C. The ISAGA results were evaluated by comparing with those detected by Danish ISAGA and ELISA and those detected by slide enzyme immunoassay (S-EIA). RESULTS: Forty-four sera from Danish pregnant women were tested by the IgM-ISAGA, 41(93.2%) were consistent with the Danish results. Sixty-seven sera from Danish and Shanghai pregnant women were detected by IgM-IgM-ISAGA and S-EIA, the total consistency rate was 92.5%. A significant correlation was found between the titers of the ISAGA and S-EIA, with a Pearson correlation coefficient of 0.589(P < 0.001). The titers of ISAGA were eighteen times higher than those of S-EIA. This method enables the detection of IgM antibodies as low as approximately 0.08 IU/ml. CONCLUSION: The IgM-ISAGA is therefore sensitive, specific, easy to perform, and is useful for mass screening and diagnosing recent Toxoplasma infection or reactivation.

Agglutination Tests↗
PubMed1998

The alternation of optokinetic responses driven by moving stimuli in humans.

When the two eyes were exposed dichoptically to two oppositely moving patterns, the alternating OKN was elicited, in which the eye movements tracked the two moving stimuli alternately. In the present experiment, two oppositely moving stimuli were periodically exchanged between the eyes, the results showed that the alternation of OKN direction was not affected by this exchange. It suggests that alternating OKN was not controlled by rivalry between the two eyes but between two perceived motion patterns.

Functional Laterality↗
PubMed1998

The role of protein kinase C alpha and epsilon isozymes in DNA synthesis induced by muscarinic receptors in a glial cell line.

Acetylcholine has been shown to induce proliferation of human astrocytoma cells by activating muscarinic receptors, particularly the m3 subtype. In the present study the role of protein kinase C in DNA synthesis induced by carbachol has been investigated. Carbachol-induced [methyl-3H]thymidine incorporation was inhibited by the protein kinase C inhibitors GF 109203X and staurosporine. However, carbachol-induced DNA synthesis was only partially reduced by protein kinase C down-regulation by phorbol 12-myristate 13-acetate (PMA), and maximal concentrations of carbachol and PMA had an additive effect on [methyl-3H]thymidine incorporation. Exposure for 24 h to maximally effective concentrations of carbachol did not induce down-regulation of protein kinase C alpha, and caused a small but significant down-regulation of protein kinase C epsilon; cells exposed for 24 h to carbachol were still able to respond with protein kinase C translocation to PMA stimulation. Carbachol caused a significant increase of phorbol ester binding, but did not stimulate protein kinase C alpha translocation, while it caused a short-lasting translocation of protein kinase C epsilon; however, protein kinase C epsilon translocation was not correlated with the time-course of carbachol-induced increase in [methyl-3H]thymidine incorporation. On the other hand, the time-course of translocation/down-regulation of protein kinase C alpha and protein kinase C epsilon induced by PMA was in good correlation with the time-course of PMA-induced [methyl-3H]thymidine incorporation. These results suggest that protein kinase C alpha may not be involved in DNA synthesis induced by muscarinic receptors stimulation in 132-1N1 astrocytoma cells, while protein kinase C epsilon appears to play a role in the initial exit from G0/G1 phase, though it cannot be considered the major determinant for sustained proliferation.

Astrocytoma↗
PubMed1998

Effects of diabetes and level of glycemia on all-cause and cardiovascular mortality. The San Antonio Heart Study.

OBJECTIVE: Although the level of hyperglycemia is clearly a risk factor for microvascular complications in diabetic patients, its role in macrovascular complications remains controversial. We followed 4,875 subjects (65% Mexican-American) for 7-8 years to investigate the effects of diabetes and hyperglycemia on all-cause and cardiovascular disease (CVD) mortality. These end points were also analyzed according to quartiles of baseline fasting plasma glucose among diabetic participants. RESEARCH DESIGN AND METHODS: The Cox proportional hazards model was used to estimate the relative risks (RRs) for all-cause and CVD mortality. RESULTS: Diabetes was significantly associated with increased all-cause mortality (RR [95% CI] = 2.1 [1.3-3.5] in men; 3.2 [1.9-5.4] in women) and increased CVD mortality (3.2 [1.4-7.1] in men; 8.5 [2.8-25.2] in women). Among diabetic subjects, those in quartile 4 had a 4.2-fold greater risk of all-cause mortality (P < 0.001) and a 4.7-fold greater risk of CVD mortality (P = 0.01) than those in quartiles 1 and 2 combined. After further adjustment for other potential risk factors, subjects in quartile 4 had a 4.9-fold greater risk of all-cause mortality and a 4.9-fold greater risk of CVD mortality than those in quartiles 1 and 2. In addition, hypertension, current smoking, and cholesterol > 6.2 mmol/l were significant predictors of CVD mortality using Cox models. CONCLUSIONS: We conclude that diabetes is a predictor of both all-cause and CVD mortality in the general population and that both hyperglycemia and common CVD risk factors are important predictors of all-cause and CVD mortality in diabetic subjects.

Activities of Daily Living↗
PubMed1998

[The enzymes activity of intestine grafts after combined small bowel/liver transplantation in rats].

OBJECTIVE: To study the alteration of the enzymes activity of intestine grafts after combined small bowel/liver transplantation in rats and the relations between their changes, functions and immune rejection. METHOD: A kind of model of combined small bowel/liver transplantation (SLT) was established in SD closed colony rats. The enzymes activity of grafts were examined at regular postoperative intervals with histochemical methods. RESULT: The enzymes activity of grafts disappeared eventually in isolated small bowel transplantation rats. Contrary, those in SLT rats were remained and recovered after operation. CONCLUSION: The rejection in grafted intestine can be prevented or delayed in SLT rats. The examination of activity of enzymes and nerves in grafts may be used to monitor rejection and study function of grafts.

Animals↗
PubMed1997

Waist circumference as the best predictor of noninsulin dependent diabetes mellitus (NIDDM) compared to body mass index, waist/hip ratio and other anthropometric measurements in Mexican Americans--a 7-year prospective study.

Although a number of obesity-related variables are recognized risk factors for NIDDM, few studies have addressed which one is the best predictor. A cohort of 721 Mexican Americans aged 25-64 years who were free of NIDDM at baseline were followed for an average of 7.2 years; 105 new cases of NIDDM were diagnosed. Body weight, body mass index (BMI), waist and hip circumferences, waist/hip ratio (WHR), triceps and subscapular skinfolds were all positively predictive of NIDDM independent of age and sex. There were modest to strong correlations between these anthropometric variables, however, waist circumference was the strongest predictor of NIDDM. The predictive power of a single measurement of waist circumference was at least equal to that of WHR and BMI combined. The risk of NIDDM for those in the highest quartile of waist circumference was 11 times greater than for those in the lowest quartile (95% confidence interval: 4.2-28.8). The waist-NIDDM relation was stronger in subjects with BMI < or = 27 kg/m2 (OR: 6.0 for a 1 SD difference) than in subjects with BMI > 27 kg/m2 (OR: 1.7 for a 1 SD difference). In multivariate analysis, waist circumference was the only significant predictor of NIDDM in models that included other anthropometric variables either separately or simultaneously. WHR and BMI were independent predictors of NIDDM after adjustment for each other, however, their predictive abilities disappeared after adjustment for waist circumference. The data indicate that waist is the best obesity-related predictor of NIDDM. This finding suggests that the distribution of body fat, especially abdominal localization, is a more important determinant than the total amount of body fat of the development of NIDDM in Mexican Americans.

Adult↗
PubMed1997

Changes in lipids associated with change in regular exercise in free-living men.

OBJECTIVE: To investigate the relationship between regular exercise and plasma lipid profiles in free-living men. METHODS: Seven hundred eighty men between the ages of 25 and 65 years were included in this study. The medical history, physical examination, and blood tests were obtained at baseline and 1 year later. At the end of the study, 430 (55.1%) men reported the same amount of regular exercise as a year earlier; 199 (25.5%) men reported an increased level, and 151 (19.4%) men reported a decreased level. RESULTS: Compared to the group with same exercise, men who increased their level of regular exercise had a significant increase in high-density lipoprotein cholesterol (HDLC) (mean 4.76 versus 2.83 mg/dL, p < 0.005) and significant decreases in the ratio of total cholesterol/HDLC (mean -0.72 versus -0.42, p < 0.001) and triglycerides (mean -18.2 versus -6.27 mg/dL, p < 0.001). The changes in lipid profiles appeared to have a dose-response relationship from the increased exercise, same exercise, to decreased exercise groups. Overweight and normal-weight men had a similar tendency to improve their lipid profiles by exercise. The improvement in plasma lipid profile associated with increased regular exercise persisted after controlling for potential confounders. CONCLUSIONS: The results indicate that the relationship between physical activity and favorable lipid profiles exists in men with mild-to-moderate physical activity.

Adult↗