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Biomedical subjects

Y X Wu

Publications and source records attributed to Y X Wu.

At least 19 recordsLinked to original sources
PubMed2007

Enteral water for hypernatremia and intestinal morbidity in infants less than or equal to 1000 g birth weight.

OBJECTIVE: To evaluate the relationship between enteral water infusion for hypernatremia and significant intestinal morbidity in infants or=150 (high sodium control), >or=150 and treated with sterile water (study group). Significant intestinal morbidity was defined as probable or proven necrotizing enterocolitis or spontaneous intestinal perforation. Statistical analysis included Student's t test for continuous variables and chi(2) with Yeats correction for frequency variables. Multivariate logistic regression analysis was then performed to evaluate confounding variables among groups. RESULTS: The incidence of intestinal morbidity was significantly higher in the high sodium-water treated group compared to each of the other groups (13/33 (38%) for high sodium-water versus 16/100 (16%) for high sodium control and 18/188 (10%) for normal sodium control, P<0.01 chi(2)). Logistic regression analysis indicated that enteral water and hydrocortisone were risk factors for significant intestinal morbidity. CONCLUSIONS: Enteral sterile water for hypernatremia appears to be associated with significant intestinal morbidity in infants <or=1000 g. Hydrocortisone is also a risk factor.

Enteral Nutrition↗
PubMed2002

Study of feed temperature control of chromatography using computional fluid dynamics simulation.

Recently preparative high-performance liquid chromatography (HPLC) has been used more and more frequently to separate drugs and natural substances. However, large-scale HPLC easily tends to reduce the yield and purity of the product. Hydrodynamic and heat factors play an important roles. Generally, in a large-scale HPLC column, the tracer profile inside column will take on a parabolic shape because of the distributor, which will impact the separation performance of the column. With the inlet temperature suitably lower than the wall temperature, this situation could be improved to some extent. In this work, some experiments were conducted using HPLC, with a column 10 cm in diameter to determine the optimal temperature difference between wall and inlet temperatures. The wall temperature was fixed at about 30 degrees C and the inlet temperature varied from 15 to 30 degrees C. The flow-rate of the eluent, methanol, was 300 ml/min. The experimental result was simulated using CFD software FLUENT 4.4.4. The simulated temperature field fitted the experimental one very well and the simulated flow, temperature and tracer distribution inside column could provide good explanation of separation performance under different conditions. In addition, the simulation could at least approximately predict the optimal temperature difference.

Chromatography, High Pressure Liquid↗
PubMed2001

Protective effects of nitroglycerin-induced preconditioning mediated by calcitonin gene-related peptide in rat small intestine.

Previous studies of myocardium have shown that ischemic preconditioning could be mimicked by nitroglycerin through stimulating the release of calcitonin gene-related peptide (CGRP). The present study examined whether nitroglycerin could also provide a preconditioning stimulus in the peripheral vascular bed (the anse intestinalis of rat), and whether endogenous CGRP is involved in this process. The model of in situ perfusion was prepared with rat small intestine. One hour of ischemia and 15 min of reperfusion caused a significant impairment of intestinal morphology and an increase in the release of both lactate dehydrogenase and malondialdehyde. Pretreatment with nitroglycerin, 10(-7), 3 x 10(-7), 10(-6) M for 5 min produced a significant improvement of intestinal tissue morphology and a decrease in the release of both lactate dehydrogenase and malondialdehyde. However, the protection afforded by nitroglycerin was abolished by CGRP-(8-37), a selective CGRP acceptor antagonist. Pretreatment with capsaicin, which specifically depletes the transmitter content of sensory nerves, also abolished the protection by nitroglycerin. In addition, the content of CGRP-like immunoreactivity in the effluent was increased during nitroglycerin perfusion. On the other hand, the results from the in vivo experiment showed that nitroglycerin (i.v. 0.13 mg/kg) injected 5 min before prolonged ischemia could provide significant protection against the injury caused by 30-min ischemia and 1-h reperfusion in the rat small intestine, but would also cause a significant increase in the levels of CGRP in the plasma. All these findings suggest that nitroglycerin-induced preconditioning is related to stimulation of CGRP release in the rat small intestine.

Animals↗
PubMed2001

Role of endogenous opioid peptides in protection of ischemic preconditioning in rat small intestine.

This study investigated the protective effects of ischemic preconditioning on intestinal ischemic injury and the role of endogenous opioid peptides (EOP) in these effects. Ischemia-reperfusion (I/R) induced by 30-min of ischemia and 60-min of reperfusion significantly increased the levels of malondialdehyde (MDA) and lactate dehydrogenase (LDH) and resulted in serious intestinal edema (wet weight/dry weight). The ischemic preconditioning (PC) elicited by three 8-min occlusion periods interspersed with 10-min reperfusion markedly attenuated intestinal injury caused by ischemia-reperfusion. Pretreatment with morphine (300 microg x kg(-1), i.v.) 10-min before ischemia and reperfusion mimicked the protection produced by PC. Naloxone (3 mg x kg(-1), i.v.) abolished the protection of morphine-induced preconditioning and ischemic preconditioning in rat intestine. However, there were no changes between naloxone alone and control groups. Treatment with naloxone before ischemia-reperfusion had no effect on animals compared with the I/R group. In addition, we also measured the content of endogenous opioid peptides (Leu-enkephalin) in the effluent which was collected before and during preconditioning. It was shown that the release of leu-enkephalin was markedly increased during preconditioning. These results suggested that EOP might play an important role in PC in rat small intestine.

Analgesics, Opioid↗
PubMed2000

Tyrosine phosphorylation and cellular redistribution of ezrin in MDCK cells treated with pervanadate.

Ezrin is a key protein in membrane-cytoskeleton interaction and is expressed primarily in actin-rich surface projections. Activation in protein tyrosine phosphorylation apparently regulates the structure and function of ezrin. In this study, we found that pervanadate (PV, the complexes of vanadate with hydrogen peroxide) caused an increase in tyrosine phosphorylation of ezrin and affected its cellular redistribution. Treatment of Madin-Darby canine kidney (MDCK) cells with pervanadate resulted in a dramatically increased tyrosine phosphorylation of ezrin within two to five min and the level reached the maximum after 60 min. This was accompanied by an alteration in the subcellular distribution of ezrin. Immunofluorescence and scanning laser confocal microscopy analysis revealed that, after PV stimulation, ezrin was redistributed from cytosol to the apical and lateral membrane domains. This occurred within five min, and more obvious redistribution to the lateral membrane domain was observed after 30 min. Furthermore, immunoblotting of ezrin in cell fractionation experiments showed that, in PV-treated MDCK cells, cytosolic ezrin was translocated to the membrane fraction, while there was no change in the level of ezrin associated with the actin-cytoskeleton. Therefore, cytoplasmic signaling may result in activation of ezrin in tyrosine phosphorylation, which is induced by PV stimulation. These results suggest that ezrin has qualities that might play a role in modulation of cell shape and adhesion.

Amino Acid Sequence↗
PubMed1999

Pulmonary hypertension in systemic lupus erythematosus.

A prospective echocardiographic and clinical study was performed on 84 Chinese patients with systemic lupus erythematosus (SLE) and 99 controls to investigate the prevalence and the mechanism of pulmonary hypertension (PH) in SLE. Comparison between Doppler estimation and catheterization measurement was made in 12 cases to validate the predictive method. Compared to normal subjects, lupus patients had significantly increased systolic pulmonary artery pressure (SPAP) (29.59 +/- 12.52 vs 19.64 +/- 5.82, P < 0.001), mean pulmonary artery pressure (MPAP) (15.11 +/- 7.36 vs 10.21 +/- 4.72, P < 0.001) and total pulmonary resistance (TPR) (315.85 +/- 190.65 vs 220.37 +/- 55.92, P < 0.001). Nine of the 84 patients presented PH, defined as SPAP < 30 mmHg and MPAP > 20 mmHg. Pulmonary hypertensive patients had higher serum endothelin (ET) than non-pulmonary hypertensive patients, were more commonly in active stages, and presented Raynaud's phenomenon and rheumatoid factors. ET level was correlated with echocardiographic pulmonary pressure. Pulmonary hypertension commonly occurs in Chinese patients with SLE (11%), and it correlates with the lupus activity and the elevation of serum endothelin.

Adolescent↗
PubMed1999

Ischemic preconditioning mediated by activation of KATP channels in rat small intestine.

AIM: To study whether the protective effects of ischemic preconditioning against rat small intestine ischemia/reperfusion injury could be mediated by KATP channel opener. METHODS: Preconditioning (Pc) was induced by 3 cycles of 8-min superior mesenteric artery (SMA) occlusion and 10-min reperfusion before prolonged ischemia. Cromakalim (Cro 75 micrograms.kg-1) and glibenclamide (Gli 8 mg.kg-1) were injected i.v. 10 min before prolonged ischemia and Pc, respectively. RESULTS: Compared with ischemic reperfusion (IR) group, Pc before prolonged ischemia (Pc + IR) decreased LDH release [(380 +/- 55) vs (559 +/- 49) U.L-1, P < 0.05], attenuated intestinal edema [wet weight/dry weight (WW/DW), 5.6 +/- 0.6 vs 6.34 +/- 0.29, P < 0.05], ameliorated intestinal histological damage (grading scale, 3.4 vs 5.7, P < 0.01), and improved reperfusion-induced hypotension. These effects of Pc were mimicked by Cro [LDH, (298 +/- 40) vs (559 +/- 49) U.L-1, P < 0.05; WW/DW, 5.6 +/- 0.4 vs 6.34 +/- 0.29, P < 0.05; grading scale, 3.6 vs 5.7, P < 0.01] and abolished in the presence of Gli [LDH, (624 +/- 44) vs (559 +/- 49) U.L-1; WW/DW, 6.6 +/- 0.6 vs 6.34 +/- 0.29; grading scale, 5.7 vs 5.7; P > 0.05] compared with IR group, respectively. CONCLUSION: Ischemic preconditioning on the rat small intestine is mediated by activation of KATP channels.

Adenosine Triphosphate↗
PubMed1995

Immunocytochemical study of microvilli in a gastric carcinoma-derived cell line.

To study the structural components of microvilli of the KATO-III cell, we used anti-villin, -ezrin, and anti-MVM (microvillous membrane prepared against mouse intestinal microvilli) antibodies. Villin and ezrin cross-link actin bundles of microvilli such as those in the small intestine and renal proximal cells. Electromicroscopically, the cytoskeletal core of microvilli of the KATO-III cell was constituted of actin-filament bundles. The anti-villin antibody but not anti-ezrin antibody reacted with the KATO-III cell as demonstrated by FITC-immunofluorescence and PAP-staining. Anti-villin, anti-MVM, but not anti-ezrin antibody, reacted with the KATO-III cell surface and with intracellular materials. Western blot analysis using anti-villin and anti-MVM antibodies revealed proteins of approximately 95 kDa (villin), and 15 kDa in the microsomal membrane fractions of KATO-III cells, respectively. Immunocytochemical and confocal laser microscopic studies showed that the cell-surface and the intracellular microcysts of KATO-III cells were preferentially decorated by anti-villin and anti-MVM antibodies. These data suggested that some actin-binding proteins, such as villin, were localized at the cell surface and on some of the intracellular cytoplasmic structures of the KATO-III cell.

Animals↗
PubMed1994

Primary culture of smooth muscle cells from benign prostatic hyperplasia.

Primary cultures of smooth muscle cells (SMCs) were derived from the human prostate obtained from four patients with symptomatic benign prostatic hyperplasia (BPH) undergoing open prostatectomy, using collagenase digestion and preferential adhesion techniques. SMCs attached to the plastic substrate by 6 to 10 h, proliferated by 2 to 3 days, and reached confluency by 10 to 14 days with a "hill-and-vallery" pattern. Immunocytochemical staining of cultured SMCs using anti human muscle-specific actin monoclonal antibody (HHF35), confirmed that more than 90% primary cultured cells were positive for HHF-35. Transmission electron microscopy of SMCs revealed dense myofibrils (6-8 nm width) showing focal density, and was compatible to smooth muscle cells. This primary culture will be utilized to provide a useful model to investigate the character of smooth muscle cells and their role in the development of BPH.

Cell Division↗
PubMed1994

[Careful dissection of the pelvic plexus helps alleviate urinary retention following radical hysterectomy].

Radical hysterectomy remains to be the treatment of choice for carcinoma of the uterine cervix. As pelvic nerve plexuses are distributed in the operative field, damage to the plexuses is likely to occur, which is responsible for the post-operative atonia of the urinary bladder and urinary retention. To reduce the incidence of this postoperative complication, the composition and distribution of the pelvic nerve plexuses in relation to the utero-sacral ligament and cardinal ligament of the uterus and paravaginal tissues were carefully dissected on 11 adult female cadavers. Based on the anatomic study, due precautions were made to avoid damage to the pelvic nerve plexuses during pelvic dissection for radical hysterectomy. As a result, the duration of postoperative urinary retention was significantly reduced while the 5- and 10-year survival rates remained unchanged.

Adult↗
PubMed1992

[Analysis of isoflavones in Belamcanda chinensis (L.)DC. and Iris tectorum Maxim by square wave voltammetry].

Three isoflavones: irigenin, tectorigenin and tectoridin in Belamcanda chinensis (L.)DC. and Iris tectorum Maxim were determined by square wave voltammetry. At the potential of -1.34 V (vs Ag/AgCl) the isoflavones gave well-defined peaks in the buffer solutions of pH3-5. An excellent linear relationship was obtained between the peak current and concentration. The method can be used to analyze small amounts of sample.

Drugs, Chinese Herbal↗
PubMed1991

[Preservation of pelvic nerve plexus during radical hysterectomy].

Preservation of the pelvic nerve plexus at the sites of uterosacral and cardinal ligaments was practiced during radical hysterectomy in 104 cases of cervical cancer (study group). Conventional radical hysterectomy without preservation of nerve plexus was performed in 100 cases (control group). The amount of residual urine was measured postoperatively to evaluate the recovery of function of urination. The average time of recovery of normal urination was 18.25 +/- 1.93 days for the study group and 24.05 +/- 1.68 days for the control group (P less than 0.01). There was no difference of 5- and 10-year survival rates between these two groups (P greater than 0.05).

Female↗
PubMed1991

Factors influencing ablation of atherosclerotic plaque with argon laser.

The ablative effect of argon laser delivered fibreoptically in vitro on 234 segments of atherosclerotic human aorta was studied. The variables such as energy density, type of atheroma and immersion media were included, and all irradiated specimens were subsequently submitted to histological examination and crater volumes in mm3 to micrometer measurements under light microscope. The results showed 1) a linear relationship between energy dose and crater volume in fibrous atheroma, 2) significantly greater damage or surrounding in the higher energy dose groups, 3) a lower dose response in calcified tissue than in fatty streaks or fibrous atheroma, and 4) immersion of tissue in blood during ablation resulted in a significantly greater dose response than immersion in plasma or saline, and the corresponding surrounding tissue damage was greatest when immersed in blood. Thus, argon laser is both effective and predictable in response during ablating of atheromatous tissue. The efficacy of the process is dependent on immersion medium, while the degree of surrounding tissue damage is dependent on energy dose.

Angioplasty, Laser↗
PubMed1990

[Clinical observations on the treatment of hookworm, Ascaris and Trichuris infection with oxibendazole].

340 cases of hookworm infection, 196 cases of ascariasis and 178 cases of trichuriasis were treated with an anthelmintic, oxibendazole, 15mg/kg.d x 3d; 102, 70 and 66 cases of respective infections were treated with pyrantel 10mg/kg.d x 3d and 108, 74 and 63 cases took placebo for comparison and as control under double-blind observations. Re-examinations of the stool were performed after the treatment. Among the cases treated with oxibendazole, the egg negative conversion rates of hookworm, Ascaris and Trichuris were 70.3-80.6%, 92.5-97.8 and 67.0-71.0% respectively. The egg reduction rates of hookworm were 98.1-98.6%. The larval negative conversion rates of Ancylostoma duodenale and Necator americanus were 77.7 and 83.2% respectively. Among the cases treated with pyrantel, the egg negative conversion rates of the three above mentioned parasites were 73.5, 90.0 and 28.8% respectively. The egg reduction rate of hookworm was 98.8%. Among the cases treated with placebo, the egg negative conversion rates of the three above mentioned parasites were 6.5, 29.7 and 7.9%. No marked adverse reactions were observed by clinical and laboratory examinations.

Animals↗
PubMed1989

Acquired cytomegalovirus infection of breast milk in infancy.

A cross-sectional study was conducted to examine the rate of cytomegalovirus (CMV) shedding through breast feeding and the rate of acquired infection by the infants. Among the 104 seropositive breast-feeding mothers, CMV was recovered in the milk in 19 cases, with a milk shedding rate of 18.3%. Isolation of CMV from the urine of the infants of the 188 seropositive mothers found 36 positive cases. Of the 36 cases, 15 of 19 fed on CMV-positive milk were infected through breast-feeding, with an infection rate of 78.9%; 11 of the 85 fed on CMV-negative milk were infected, the infection rate being 12.9%; and 10 (11.9%) of 84 fed on cow's milk were infected. These demonstrate that the rate of infection in infants fed on virus-positive milk was significantly higher than those fed on virus-negative milk or cow's milk (P less than 0.005).

Breast Feeding↗
PubMed1989

[Diagnosis of congenital CMV infection by specific CMV IgM antibody in cord serum with ELISA].

Cytomegalovirus IgM (CMV IgM) antibodies of 582 cord sera from 6 hospitals in Chengdu were detected by direct ELISA and indirect ELISA. Twenty-seven cases with CMV IgM antibody positive were detected from 582 cord sera. Twenty-five and 15 cases were found to have CMV IgM antibody by direct ELISA and indirect ELISA, respectively (P greater than 0.05). Indirect ELISA for detection CMV IgM antibody was only interfered by high concentration of CMV IgG and rheumatoid factor. Children with CMV IgM antibody positive were followed-up to 5-6 months. Hearing loss was detected by impedance audiology in only 2 cases. But the other physical and mental examinations were normal. The result showed that the prevalence of congenital CMV infection is 4.6% in our study and direct ELISA method is more specific and sensitive than indirect ELISA method to detect CMV IgM antibody in cord serum.

Antibodies, Viral↗
PubMed1989

Aircraft noise-induced temporary threshold shift.

Audiograms were taken on 20 young men before and immediately after exposure to Fighter-6 ground running-up noise, and their course of recovery was followed. The sound levels at the engine hatch were 117-128 dB(A). The noise-induced temporary threshold shift was more than 13 dB. The maximum threshold shift occurred at 4 kHz. The shift in the low and speech frequencies recovers more rapidly and is completed in 30 min, whereas that in the high-frequency range recovers much more slowly, not returning to normal until 24 h later. High-frequency hearing loss is at risk in groundcrew. In order to prevent hearing damage, they ought to wear ear-protectors. We discovered that the V-shaped depression was not at 4 kHz but at 6 kHz. The former view concerning the pathogenesis of "4 kHz depression", therefore, is open to question. This interesting subject warrants further study.

Adolescent↗