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Biomedical subjects

Z Yu

Publications and source records attributed to Z Yu.

At least 109 records · Page 6Linked to original sources
PubMed2000

[Construction and nucleotide sequence assay of human anti-HBs variable region single-chain antibody gene].

The VH and Vk gene which were acquired using phage display technology have been combined by a linker encoding a flexible peptide (Gly4 Ser)3 to form a single-chain. Its nucleotide sequence was assayed after cloning the scFv gene into middle plasmid. The successful construction of single-chain gene lays the foundations for the subsequent expression and production of double functional antibody.

Amino Acid Sequence↗
PubMed2000

[Effect of waterlogging on senescence of winter wheat root system at booting stage].

By applying 3 winter wheat cultivars of different water-resistance, the effect of waterlogging at booting stage on the growth and development of root system, 32P absorption and its distribution, and senescence of root system was studied with soil column culture. Waterlogging at booting stage reduced root dry weight, its activity and SOD activity, and increased the relative permeability of plasma membrane and the membrane-lipid preoxidation level(MDA content) of root system. Meanwhile, waterlogging influenced the 32P absorption, transportation and distribution, and consequently, speeded up the senescence of root system.

Absorption↗
PubMed2000

[Serum leptin levels during pregnancy].

OBJECTIVE: To study the serum leptin levels in Chinese pregnant women, and to discuss the relationship between leptin level and pregnancy. METHODS: Serum leptin concentrations of 251 pregnant women (13.6 to 30.9 gestational weeks) were measured with radioimmunoassay, and 35 age and body mass index (BMI) matched non-pregnant women were selected as control. Serum leptin concentrations were compared between pregnant and control women, correlations between leptin concentrations and gestational age, weight, BMI, blood pressure and other parameters were analyzed. RESULTS: In these pregnant women, aged (28.5 +/- 3.9) years, BMI (23.6 +/- 2.8) kg/m2, serum leptin concentrations were (15.1 +/- 7.4) micrograms/L; while in control women, aged (27.4 +/- 3.8) years, BMI (22.6 +/- 2.5) kg/m2, serum leptin concentrations were (9.1 +/- 4.9) micrograms/L. The mean age and BMI are comparable between 2 groups. Serum leptin concentrations in pregnant women were much higher than those in control women (P < 0.001). Within the pregnant women, serum leptin concentrations were significantly correlated to body weight(r = 0.529), BMI (r = 0.551,), waist circumference (r = 0.564), height of uterus bottom (r = 0.151), systolic blood pressure (r = 0.134) and diastolic blood pressure (r = 0.251). During pregnancy, serum leptin concentrations rose along with the gestational age, although no statistical difference was revealed up to 30th gestational week. CONCLUSIONS: Leptin is a hormone intimately related to the pregnancy, its concentrations are much higher during pregnancy than those of non-pregnant women with matched age and BMI. Like in non-pregnant women, leptin levels are significantly correlated to body weight and BMI, and also correlated to blood pressure, the correlation between leptin and diastolic blood pressure is more evident, indicating that serum leptin may serve as a marker for detecting and monitoring pregnancy complications.

Adult↗
PubMed2000

[Clinical research of Hashimoto's disease with thyroid carcinoma].

OBJECTIVE: To study the relation diagnosis and treatment of Hashimoto's disease (HD) with thyroid carcinoma (TC). METHODS: The relation diagnosis and surgical treatment of 150 cases of HD including 15 cases of TC were analyzed. RESULTS: The coexistent rate of HD with TC was 10%. The 15 cases were all women, with a mean age of 36.5 years, and they were surgically treated. Follow-up for 4 months to 19 years showed that the 15 cases were alive without recurrence. CONCLUSION: Surgical treatment is indicated for patients with HD associated with TC. The essential factors for diagnosis and rational treatment are a detailed understanding of clinical feature, routine examination of serum antibodies, B-ultrasonic examination and selective FNAC.

Adult↗
PubMed2000

[Dural arterovenous fistula involving cavernous sinus].

OBJECTIVE: To study the pathogenesis and treatment of dural arteriovenous fistulas (DAVFS) involving the cavernous sinus. METHODS: 32 cases were embolized with particle by microcatheterization via endovascular approach and ervation by digital substraction angiography. Of the 32 cases, 14 were embolized by microsoils through superior petrosal sinus approach into the cavernous sinus. RESULTS: In 28 of the 32 cases the fistulas were completely embolized angiographically. The fistulas were partly embolized in 4 of the 32 cases. The carotid artery was compressed for 6 months. One week later, the fistula disappeared angiographically. No fistulas were found during the follow-up for 6 months to 8 years. CONCLUSION: Endovascular treatment of DAVFS involving the cavernous sinus is effective.

Adolescent↗
PubMed2000

[Effect of combined operation including splenorenal shunt as the main technique for portal hypertension in children].

OBJECTIVE: To assess the effect of combined operation including splenorenal shunt as the main technique for portal hypertension in children. METHODS: 22 patients were reviewed and followed up from 1980 to 1998 (13 male, 9 female). The average age was 9.45 years. Intrahepatic type was shown in 16 patients and prehepatic type in 6. All patients had hematemesis, hematochezia or severe esophageal varices. Liver function was classified Child A in 14 patients, B in 7, and C in 1. Combined operation was performed in all patients. RESULTS: There was no operative death in this group. 21 patients (95.5%) were followed up, with the longest time for 19 years (average 9.58 years). Six patients had hemorrhage from the esophageal varices after operation, and two died of hemorrhage. The survival rates of < 3, -5, -10, -15, > 15 years were 95.2%, 100%, 93.8%, 100%, 100% respectively. No hepatic encephalopathy was noted. CONCLUSION: In treating and preventing hemorrhage from the esophageal varices, combined operation including splenorenal shunt as the main technique is the first choice for the portal hypertension in children. Attention must be paid to the patients who had hemorrhage from the esophageal varices after operation.

Adolescent↗
PubMed2000

[Hyperpolarized cardiac arrest with ATP-sensitive potassium channel opener on myocardial protection during CPB].

OBJECTIVE: To investigate the myocardial protective effects of pinacidil-induced hyperpolarized arrest and compare them with those induced with depolarized hyperkalemic arrest. METHODS: 18 dogs were equally divided into three groups. In the hypothermic hyperpolarization group (LH group), after aortic cross-clamping, a single dose of 4 degrees C pinacidil containing St. Thomas cardioplegic was infused through the aortic root. Temperature during CPB was kept between 26 - 28 degrees C and warmed to 37 degrees C before aortic declamping. Global ischemia lasted 60 min and then reperfusion started for 30 min. In the normothermic hyperpolarized group (WH group), the same procedure was set as in the LH group, except maintaining temperature of 35 - 37 degrees C for CPB and pinacidil solution. In the control group (group C), no pinacidil in St. Thomas solution was the only difference to the other 2 groups. Cardiac arrest and its recovery, the ultrastructure of the myocardium and hemodynamic during ischemia and after reperfusion were observed in the 3 groups. RESULTS: (1) The percentages of normal mitochondria and glycogen were not changed significantly during ischemia and after reperfusion in the LH group, but declined markedly in the group C at ischemic 30, 60 min, and reperfusion for 20 min (P < 0.01). In the WH group, they were lower than those of the group LH, but higher than those of the group C before ischemia. (2) The recoveries of CO, SV, CI, LVSW, RVSW, MAP in the LH group were significantly better than those in the other two groups after reperfusion for 15 minutes and 30 minutes (P < 0.05 or 0.01). However, they were much better in the WH group than in the group C (P < 0.05 or 0.01). (3) The time from cardioplegic infusion to cardiac arrest was shorter in the group C and the group LH than in the group WH. CONCLUSIONS: Myocardial protection for global ischemia during CPB could be well achieved with hyperpolarized cardiac arrest induced by ATP-sensitive potassium channel opener, pinacidil, especially in the hypothermic state. The protection is weaker in normothermia but is still stronger than that with traditional depolarized arrest.

Adenosine Triphosphate↗
PubMed2000

[The relationship between the chromaffin granule number and the granule calcium content in the adrenal medulla of restrained rats].

Morphometry of numerical density and electron probe X-ray quantitative microanalysis were used to measure the alterations in the number and calcium content of chromaffin granules in adrenal medulla cells during emergency reaction of restrained rats. It was found that both the alterations showed monotonic decrease during the period of restraint, but the rate of decrease of the calcium content was significantly faster than that of the granules. These data are consistent with the hypothesis that calcium release from the granules may increase the cytoplasmic calcium concentration, which again triggers off the granule exocytosis.

Adrenal Medulla↗
PubMed2000

[Classification of eyelid and designs of the double-eyelid operation].

OBJECTIVE: To discuss the morphological characters of eyelids and the designs of double-eyelid operation on various eyelids. METHODS: The classification of eyelids was named according to morphological characters of eyelids from 6847 cases. A survey of 92 cases treated by double-eyelid operation was carried out to compare the external eye morphology of pre-operation with that of post-operation. RESULTS: There were several types of eyelids, which were morphologically classified according to eyes' length and height, eyelid skin thickness, eyeball protrusion and eye shape, including eyelids with long and narrow eyes, eyelids with thin and soft skin, eyelids with thick subcutaneous tissue, eyelids with small and round eyes, eyelids with protruding eyeball, and eyelids with triangle eyes. The aesthetic effects of double-eyelid operation on all these types of eyelids were evaluated. CONCLUSION: The indication of double-eyelid operation should be considered correctly, and the design should be made according to classification of the morphological characters of eyelids. Double-eyelid operation may be not appropriate for the eyelids with small, round and protruding eyes.

Adolescent↗
PubMed2000

[Screening of acrystalliferous mutants from Bacillus thuringiensis and their transformation properties].

After elevating growth temperature of YBT-1463 and other 8 Bacillus thuringiensis parental strains to 42 degrees C, 9 acrystalliferous(Cry-) mutants were obtained, and then a series of partial plasmid-cured mutants were further obtained from 3 Cry- mutants BMB151, BMB154 and BMB160 by elevating temperature to 44 degrees C. One of which, BMB170, was further treated by elevating temperature to 46 degrees C and adding 0.05% SDS as the plasmid-curing agent. The resulting mutant, which was designated BMB171 and had no resident plasmid, was finally obtained. The studies on the transformation efficiency and stability of Cry- mutants showed that the transformation frequencies, as well as stability of several exogenous plasmids(pHT3101, pBMB1736, etc.) introduced into Cry- mutants by electroporation, were correlated with the numbers of resident plasmids bearing by the relevant recipients, the patterns of plasmid replicons and the sizes of those exogenous plasmids. Meanwhile, a much higher electro-transformation frequencies of Cry- mutants than the parental strain YBT-1463 was found, and the highest of the transformation frequency, in BMB 171, could reach up to 10(7) transformants/microgram DNA, and the stability of those exogenous plasmids in BMB171 were also higher than in other Cry- mutants and YBT-1463 strain.

Bacillus thuringiensis↗
PubMed2000

[Expression and insecticidal characteristics of cry3A in Lepidoptera-specific Bacillus thuringiensis].

The cry3A gene coding Coleoptera-specific protein was transformed into a wild strain YBT803-1 by electroporation, A transformant BMBY-001 was obtained. SDS-PAGE analysis demonstrated that cry3A could express 64 kD protein in BMBY-001. However, the expression of cry1Ab and cry1Ac were effected. Bioassay showed that BMBY-001 was not only highly toxic to Phyllodecta vulgatissima larva(LC50 0.413 microL/mL) but also toxic to Plutella xylostella(LC50 3.319 microL/mL).

Animals↗
PubMed2000

[Characterization of the insecticidal crystal protein genes of Bacillus thuringiensis YBT-1520].

The insecticidal crystal protein genes of highly toxic Bacillus thuringiensis YBT-1520 were analyzed. Southern hybridization and PCR analysis indicated that this strain bears cry1Aa, cry1Ab, cry1Ac and cry2 genes. The copy number of three cry1A genes is different and cry1Ac gene (here named cry218) is the highest. The restriction location of three genes is different from that in typical strains, such as HD-1 and HD-73 strains. 4190 bp nucleotide sequence of cry218 gene was determined and this gene was named cry1Ac10 in the recently published gene nomenclature.

Bacillus thuringiensis↗
PubMed2000

[A new resolution vector with cry1Ac10 gene based on Bacillus thuringiensis transposon Tn4430].

A new resolution vector with cry1Ac10 gene based on TnpI-mediated site-specific recombination system of Bacillus thuringiensis(Bt) transposon Tn4430 was developed. The gene cry1Ac10, encoding a protoxin against plutella xylostella larvae, and the gene ori1030, from a plasmid of wide type Bacillus thuringiensis, were inserted into two copy sets of RES sites, named pBMB801. When pBMB801 was introduced into crystal negative Bt host BMB171, antibiotic resistance genes and other non-Bt DNA can be selectively eliminated. This recombinant plasmid was found very stable without antibiotic selection. The resulting strain only contained Bt DNA and is free of antibiotic resistance genes. This strategy should facilitate regulatory approval for its development as a commercial biopesticide.

Bacillus thuringiensis↗
PubMed2000

[The application of epiglottis in laryngeal function reconstruction after partial laryngectomy].

OBJECTIVE: To observe the appliance value of epiglottis in laryngeal function reconstruction after partial laryngectomy. METHODS: Thirty-two cases of glottic and superglottic carcinomas of larynx had conducted partial laryngectomy and the laryngeal function was reconstructed using epiglottis from December. 1992 to January 1996. RESULTS: Nineteen of the twenty-one glottic carcinomas and five of eleven supraglottic carcinomas were decannulated and recovered with laryngeal functions. All the patients rehabilitated deglutition in 14-18 days after surgery. None presented complication of aspiration. CONCLUSIONS: Epiglottis has many advantages in partial laryngectomy and the laryngeal reconstruction. It is easy to approach, apply and heal in short period. It also prevents aspiration and improves the decannulation rate as well as the quality of life in partial laryngectomy patients.

Adult↗
PubMed2000

Conservative management of twin pregnancy with single fetal death.

OBJECTIVE: Analysis of the cause of intrauterine death of one fetus of twin and to evaluate the outcome of conservative management of twin pregnancy with single fetal death. METHOD: A retrospective review was undertaken on PUMC hospital records of women who delivered twin between Jan. 1987 and Dec. 1998. RESULT: During the recent 12 years, 99 pregnant women were documented as twin pregnancies. Of the twin pregnancies during this period, 13 were complicated by a single intrauterine death. Four women suffered this complication during their first trimester. In the remain 9 cases one fetus died during second or third trimester. The cesarean section was given in three pregnant women soon after a single intrauterine death because of the survival fetal distress. No consumptive coagulopathy was apparent in all 13 pregnant women. It is wise that the pregnancy was managed conservatively, with regular coagulation parameters obtained. CONCLUSION: Our results support conservative management in twin pregnancies complicated by single fetal death.

Adult↗
PubMed2000

[Spectrophotometric determination of trace cadmium in polyferric sulphate flocculent].

A new sensitive method for determining trace cadmium in polyferric sulphate flocculent is proposed in the paper. The new sensitive method is spectrophotometric method. The color reagents are the butylrhodamin B and potassium iodide. The surfactant is the polyvingl alcohol(PVA). The maximum absorbency wavelength is 607 nm. The molar absorptivity is 4.99 x 10(5) L.mol-1.cm-1. The sandell sensitivity is 2.25 x 10(-4) micrograms Cd2+.cm-2. The Beer's law is obeyed for Cd(II) in the range of 0-1.5 micrograms.25 mL-1. The recovery is 96%-105% and the sample processing procedure is simple. This method has been applied to determination of trace Cd(II) in polyferric sulphate flocculent. The determining results are satisfactory.

Cadmium↗
PubMed1999

HCPTPA, a protein tyrosine phosphatase that regulates vascular endothelial growth factor receptor-mediated signal transduction and biological activity.

Angiogenesis is a tightly controlled process in which signaling by the receptors for vascular endothelial growth factor (VEGF) plays a key role. In order to define signaling pathways downstream of VEGF receptors (VEGFR), the kinase domain of VEGFR2 (Flk-1) was used as a bait to screen a human fetal heart library in the yeast two-hybrid system. One of the signaling molecules identified in this effort was HCPTPA, a low molecular weight, cytoplasmic protein tyrosine phosphatase. Although HCPTPA possesses no identifiable phosphotyrosine binding domains (i.e. SH2 or phosphotyrosine binding domains), it bound specifically to active, autophosphorylated VEGFR2 but not to a mutated, kinase-inactive VEGFR2. Recombinant VEGFR2 and endogenous VEGFR2 were substrates for recombinant HCPTPA, and HCPTPA was co-expressed with VEGFR2 in endothelial cell lines, suggesting that HCPTPA may be a negative regulator of VEGFR2 signal transduction. To pursue this possibility, an adenovirus directing the expression of HCPTPA was constructed. When used to infect cultured endothelial cells, this adenovirus directed high level expression of HCPTPA that resulted in impairment of VEGF-mediated VEGFR2 autophosphorylation and mitogen-activated protein kinase activation. Adenovirus-mediated overexpression of HCPTPA also inhibited VEGF-induced cellular responses (endothelial cell migration and proliferation) and inhibited angiogenesis in the rat aortic ring assay. Taken together, these findings indicate that HCPTPA may be an important regulator of VEGF-mediated signaling and biological activity. Potential interactions with other signaling pathways and possible therapeutic implications are discussed.

Animals↗