Biomedical subjects

P Xu

Publications and source records attributed to P Xu.

At least 91 records · Page 5Linked to original sources

PubMed1999

[The effects of Xuezhikang on neointimal proliferation and C-myc gene expression after angioplasty in rabbits].

OBJECTIVE: To investigate the effects of Xuezhikang (XZhK) on the neointimal proliferation and C-myc gene expression after angioplasty in rabbits. METHODS: Angioplasty for atherosclerotic stenosis of celiac arteries was performed in 30 male white rabbits after being fed with cholesterol-supplemented diet for 8 weeks, which were then randomized to control group, high-cholesterol group and XZhK group. After 4 weeks, the local vessels were collected for morphological observation. C-myc mRNA level was measured with RT-PCR and C-myc protein with immunohistochemical analysis. RESULTS: Morphological observation showed that the neointimal area in the XZhK group were less than the control group (P < 0.05), and that in control group were less than that in the high-cholesterol group (P < 0.05). The levels of C-myc mRNA measured with RT-PCR and the percentage of C-myc protein positive cell by immunohistochemical analysis were lower in the XZhK group than in the control and high-cholesterol group (P < 0.05), The levels in the latter two groups showed no difference (P > 0.05). CONCLUSION: XZhK can inhibit the neointimal proliferation and the expression of C-myc gene after angioplasty in rabbits.

Angioplasty, Balloon↗

PubMed1999

[Orbito-zygomatic approach for removal of tumors of the skull base].

OBJECTIVE: To evaluate the advantages and indications of orbito-zygomatic approach for removal of tumors of the skull base. METHODS: Fifteen patients with tumors of the skull base were operated on using obito-zygomatic approach. The advantages and indications of the approach were evaluated. RESULTS: In 7 cases of meningioma, total removal of the tumor was achieved in 6 cases, and subtotal removal in 1. In 4 cases of craniopharyngioma, the tumor were totally removed in 3 cases, and subtotally removed in 1. The tumor were totally removed in 2 cases of trigerminal neurilemoma and 1 case of germinoma. There was one operative death. All patients recovered except 3 who had minor extraocular parasis. CONCLUSIONS: This approach ensures additional space, and less cerebral retraction for easy access to skull base tumor, especially the large neoplasm of middle cranial base with or without orbital or posterior cranial base extension.

Adolescent↗

PubMed1999

[Study on cytotoxicity to leukemia cell and enhancement of immunologic functions of jiexinkang].

Cytotoxicity to leukemia cell and enhancement of immunologic functions of jiexinkang (JXK, traditional Chinese medicine) were observed in 34 cases of leukemia in vitro. The results showed that the leukemia cytotoxicity in the group of vincristine combined with JXK was significantly higher than that in vincristine alone. It was also found among all the observed cases that 20 refractory or recurred patients resistant to vincristine showed an obvious intention of the anti-toxicity efficiency when JXK was added. Jiexinkang alone had anti-leukemia cell effect, too. We explored JXK effects on immunologic functions in mice, and found that IFNr and NK activities of normal and experimental model mice were significantly higher than those of control group(P < 0.01). The results indicate that JXK has an effect of anti-leukemia cell and may improve the cell-immunologic functions.

Adjuvants, Immunologic↗

PubMed1999

[Research on anti-thrombosis effect of ethanol extract from beheaded leech (EEBL)].

OBJECTIVE: To study the anti-thrombosis effect of EEBL and its possible mechanism. METHOD: Using a thrombosis model induced by collagen-adrenaline in mice and an artery-vein bypass in rats. The effect of EEBL on erythrocyte membrane and thrombocyte membrane fluidity were measured by fluorescence polarization. RESULT: EEFL inhibited the thrombosis induced by collagen-adrenaline in mice and the thrombosis in artery-vein bypass in rats significantly. EEBL also enhanced in vitro erythrocyte membrane fluidity and thrombocyte membrane fluidity markedly. CONCLUSION: The anti-thrombosis effect of EEBL may possibly be associated with the enhancement of fluidity of erythrocyte membrane and thrombocyte membrane. There exist anti-thrombosis chemical constituents in the body of beheaded leech.

Animals↗

PubMed1999

[Studies on the lactate oxidase producing conditions by Edwardsiella tarda].

A bacterium producing lactate oxidase was re-screened from five strains based on previous researches. The lactate oxidase activity was the highest in strain L1 and this stain was chosen as the enzyme source. Morphological and physiological studies revealed that the bacterial strain L1 belongs to the Edwardsiella tarda Biogroup I. This stain is different from the reported strains Mycobacterium and Pediococcus, which produce lactate oxidase. The enzyme producing conditions were studied in shaking cultures, and the effects of initial pH, riboflavin, lactate and ammonia sulphate concentrations on the production were carried out respectively. The bacteria resource of enzyme is significant to pyruvate production by enzymatic method, and to the enzyme assay of lactate for medical diagnosis, and the application of enzyme electronic probe.

Culture Media↗

PubMed1999

[Effect of dialysates on ultrastructure of mouse peritoneal mesothelium].

OBJECTIVE: To observe the effect of various peritoneal dialysates on the ultrastructure of the peritoneal mesothelium. METHODS: Continuous ambulatory peritoneal dialysis mice model was made by injecting domestic lactate, acetate, and American Baxter dialysates intraperitoneally. The diaphragmatic peritoneum of the mice was taken at 10th day and 21th day respectively after injection. RESULTS: After 10 day experiment, the mesothelial ultrastructure of Baxter group was normal, but some pathological changes occurred in the peritoneal mesothelium of both domestic lactate and acetate groups. And the injury of the peritoneal mesothelium was progressing with times, e.g. adhesion and exfoliation of the microvilli, shrinkage of the mesothelial cells and even fibrous adhesion. The extent of effects on the mesothelial cells varied in three groups, the least is Baxter group. After 21 day experiments, the diameters of the stomata were (6.96 +/- 2.46) microns and (6.98 +/- 2.16) microns in both domestic lactate and acetate dialysates groups respectively, which were much greater than those in physiological condition (1.47 +/- 0.88) microns (P < 0.01). The distribution density of the lymphatic stomata were significantly increased in acetate and lactate dialysate groups compared with the control group (P < 0.01). But little effects on the lymphatic stomata were showed after using Baxter dialysate. After discontinuing experiment for 10 days, the impairment of the peritoneal mesothelium recovered in Baxter group and improved to varying degrees in both domestic dialysate groups. The lymphatic stomata were still abnormal in both domestic dialysate groups. CONCLUSIONS: Our findings indicate that lactate and acetate dialysates are more like to elicit peritoneal fibrosis and the increase of distribution density and the enlargement of the lymphatic stomata can significantly enhance their absorption effects and increase their reabsorption quantity of dialysate from the peritoneal cavity during peritoneal dialysis. These changes of the lymphatic stomata and their lymphatic reabsorption are thought to be associated with deterioration of peritoneal function, and to cause ultrafiltration failure in the patients on long-term continuous ambulatory peritoneal dialysis (CAPD) therapy.

Acetates↗

PubMed1998

[Genetic polymorphism of FXIII B subunit in seven Chinese populations].

OBJECTIVE: To understand the distribution of allele frequencies of blood factor XIIIB subunit(FXIIIB) in Chinese populations and evaluate the genetic polymorphism of FXIIIB for the purposes of population genetics and forensic haemogenetics. METHODS: The genetic polymorphism of FXIIIB subunit in seven Chinese populations was investigated. Isoelectrofocusing technique on polyoacrylamid gels followed by immunoblotting was used to determine the phenotype of individuals in each population sample. RESULTS: There were three common alleles in all the seven Chinese populations. The frequency of FXIIIB*3 was the highest, that of FXIIIB*2 was the lowest, and the one of FXXIIIB*1 was at the middle. All of them reached to the polymorphism's level. A rare variant allele was also found in some Chinese populations. Comparison of the constituents of FXIIIB phenotypes in the seven populations showed that there was no significant difference (P>0.05). The distribution of the allele frequencies in these populations reflected most likely the mode of the distribution in all Chinese populations. The phylogenetic tree and genetic distance, based on the allele frequencies of FXIIIB differentiated the populations in the world into the main ethnic groups as what other authors reported. CONCLUSION: FXIIIB is a useful genetic marker for population genetics and forensic haemogenetics.

China↗

PubMed1998

Morphometric analysis of the immunohistochemical expression of Clara cell 10-kDa protein and surfactant apoproteins A and B in the developing bronchi and bronchioles of human fetuses and neonates.

Morphometric analyses of the immunohistochemical expression of the Clara cell secretory 10-kDa protein (CC10) and surfactant apoproteins A and B (SP-A and -B) were carried out on the developing bronchi and bronchioles of human fetuses and neonates. We analysed the ratio of the number of CC10-positive cells per subepithelial length of the bronchial or bronchiolar basement membrane and found that both the bronchial and the bronchiolar population of CC10-positive cells was significantly higher than that of either SP-A or SP-B. In addition, CC10 was found to be distributed mainly in the bronchiole. CC10-positive cells began to be recognized in the late pseudoglandular phase (15 weeks of gestation) and thereafter gradually increased in the canalicular and terminal sac phases, which correspond to the active development period of the acini or peripheral airways. The earliest expression of SP-A was also noted at 15 weeks of gestation, but its positive epithelial cells were present mainly in the larger bronchi. Double immunohistochemical staining for CC10 and SP-A revealed that the CC10-positive cells lining both the bronchi and bronchioles were different from the SP-A-positive cells. This finding suggests that CC10-positive cells are functionally and developmentally heterogeneous in both fetal and neonatal lungs in humans.

Animals↗

PubMed1998

A nitrilase-like protein interacts with GCC box DNA-binding proteins involved in ethylene and defense responses.

Ethylene-responsive element-binding proteins (EREBPs) of tobacco (Nicotiana tabacum L.) bind to the GCC box of many pathogenesis-related (PR) gene promoters, including osmotin (PR-5). The two GCC boxes on the osmotin promoter are known to be required, but not sufficient, for maximal ethylene responsiveness. EREBPs participate in the signal transduction pathway leading from exogenous ethylene application and pathogen infection to PR gene induction. In this study EREBP3 was used as bait in a yeast two-hybrid interaction trap with a tobacco cDNA library as prey to isolate signal transduction pathway intermediates that interact with EREBPs. One of the strongest interactors was found to encode a nitrilase-like protein (NLP). Nitrilase is an enzyme involved in auxin biosynthesis. NLP interacted with other EREBP family members, namely tobacco EREBP2 and tomato (Lycopersicon esculentum L.) Pti4/5/6. The EREBP2-EREBP3 interaction with NLP required part of the DNA-binding domain. The specificity of interaction was further confirmed by protein-binding studies in solution. We propose that the EREBP-NLP interaction serves to regulate PR gene expression by sequestration of EREBPs in the cytoplasm.

Amino Acid Sequence↗

PubMed1998

Lung injury and oxidoreductases.

Acute lung injury represents a wide spectrum of pathologic processes, the most severe end of the spectrum being the acute respiratory distress syndrome. Reactive oxygen intermediates have been implicated as important in the pathobiochemistry of acute lung injury. The endogenous sources that contribute to the generation of reactive oxygen intermediates in acute lung injury are poorly defined but probably include the molybdenum hydroxylases, NAD(P)H oxidoreductases, the mitochondrial electron transport chain, and arachidonic acid-metabolizing enzymes. Our laboratory has focused, in particular, on the regulation of two of these enzyme systems, xanthine oxidoreductase (XDH/XO) and NAD(P)H oxidase. We observe that gene expression of XDH/XO is regulatory in a cell-specific manner and is markedly affected by inflammatory cytokines, steroids, and physiologic events such as hypoxia. Posttranslational processing is also important in regulating XDH/XO activity. More recently, the laboratory has characterized an NAD(P)H oxidase in vascular cells. The cytochrome components of the oxidase, gp91 and p22, appear similar to the components present in phagocytic cells that contribute to their respiratory burst. In human vascular endothelial and smooth muscle cells, oncostatin M potently induces gp91 expression. We believe that regulation of gp91 is a central controlling factor in expression of the vascular NAD(P)H oxidase. In summary, the studies support the concept that the oxidoreductases of vascular cells are expressed in a highly regulated and self-specific fashion.

Animals↗

PubMed1998

[Effect of zinc deficiency on apoptosis of spermatogenic cells of rat tostis].

OBJECTIVE: To study the changes of testis apoptosis in zinc deficient rats will promote the understanding of the molecular mechanism of zinc deficiency in the development and function of testis. METHODS: 16 Wistar rats were divided randomly into zinc control group (ZC) and zinc deficiency group (ZD). The serum and testis zinc contents were measured with atomic absorse method; the apoptosis of spermatogenic cells was studied with in situ nick translation (ISNT) technique. RESULTS: Under zinc deficient status, the zinc contents of the serum and testis were obviously decreased (P < 0.05). The apoptosis number of spermatogenic cells was significantly increased (P < 0.01). CONCLUSION: The adequate amount of zinc is essential to the development of testis, whereas zinc deficiency can harmfully affect it. This effect is perhaps carried out in different ways, but the increasing apoptosis numbers of spermatogenic cells might be one of molecular miechanisms of the effect of zinc defficiency on testis development.

Animals↗

PubMed1998

[Crystalloid cardioplegia at different calcium concentration: its effect on immature rabbit myocardium].

OBJECTIVE: To determine the myocardial protective effect of St. Thomas II cardioplegia at different calcium concentration on immature myocardium. METHODS: Isolated perfused neonatal rabbit hearts from three groups (the calcium concentration of St. Thomas II cardioplegia was modified: [Ca2+] 0.6 mmol/L; [Ca2+]1.2 mmol/L; [Ca2+]2.4 mmol/L) were subjected to 20 degrees C hypothermia, 90 minutes of global ischemia followed by 30 minutes reperfusion in Langendorff mode. RESULTS: Although the recovery of LVDP, +/- dp/dtmax at calcium content of 2.4 mmol/L after 10 minutes of reperfusion was significantly higher than that at 0.6 and 1.2 mmol/L calcium (P < 0.05, P < 0.01, respectively), the declined tendency of left ventricular hemodynamics in this group was detected after 20 minutes of reperfusion. By the end of 30-minute reperfusion, the left ventricular hemodynamic recovery at 2.4 mmol/L calcium did not differ from those at 0.6 mmol/L and 1.2 mmol/L calcium. Conversely, postischemic left ventricular functions at 0.6 and 1.2 mmol/L calcium were gradually improved during the 30 minutes reperfusion. Ca(2+)-ATPase activity at 2.4 mmol/L calcium showed significant increase (P < 0.01, P < 0.001), whereas ATP content was lower than that of other groups. CONCLUSION: Calcium accumulated in extracellular space during ischemia enters myocardial cell via Ca2+ channel and Ca2+/Na+ exchange after reperfusion, activates Ca(2+)-ATPase, and finally accelerates adenosinetriphosphate (ATP) consumption induced by calcium, which would be responsible for the results of our study. We conclude that, from the point of view of myocardial cell energy metabolism, St. Thomas II cardioplegia at high calcium concentration can not provide immature myocardium with optimal myocardial protection.

Animals↗

PubMed1998

Effect of crystalloid cardioplegic solution at different calcium concentration on immature myocardium.

OBJECTIVE: To determine the myocardial protective effect of crystalloid cardioplegic solution at different calcium concentration on immature myocardium. METHODS: Isolated perfused neonatal rabbit hearts from three groups, arrested by intermittent infusion of St. Thomas II cardioplegic solution with different concentration of calcium (in each group, only calcium concentration of cardioplegic solution was modified, I. [Ca2+] 0.6 mmol/L; II. [Ca2+] 1.2 mmol/L; III. [Ca2+] 2.4 mmol/L), were kept ischemic globally at 20 degrees C for 90 minutes and then followed by 30 minutes of reperfusion in Langendorff mode. RESULTS: Although the recovery of LVDP, +dp/dtmax at calcium content of 2.4 mmol/L after 10 minutes of reperfusion was significantly higher than those at 0.6 and 1.2 mmol/L calcium (P < 0.05, P < 0.01, respectively). The declined tendency of left ventricular hemodynamics after 20 minutes of reperfusion in this group was detected. By the end of reperfusion, the left ventricular functional recovery at 2.4 mmol/L calcium did not differ from those at 1.2 and 0.6 mmol/L calcium. Conversely, postischemic left ventricular functions at 0.6 and 1.2 mmol/L calcium were gradually improved during 30 minutes of reperfusion. In 2.4 mmol/L calcium group, the Ca(2+)-ATPase activity significantly increased (P < 0.01, P < 0.001) whereas myocardial ATP content was lower when compared with 1.2 mmol/L (P < 0.001) and 0.6 mmol/L calcium groups. CONCLUSIONS: Our research demonstrated that there were no statistical differences with respect to hemodynamic recovery in three groups after 30 minutes of reperfusion although left ventricular functional recovery at 2.4 mmol/L calcium accelerated early after reperfusion. In addition, with 2.4 mmol/L calcium, myocardial ATP content was decreased significantly. We conclude that, from the point of view of myocardial energy metabolism, St. Thomas II cardioplegic solution at high concentration of calcium can not provide immature myocardium with optimal myocardial protection while with 1.2 mmol/L calcium, however, better high-energy store can be preserved.

Animals↗

PubMed1998

[An EM field generator system for studying biomedical effects].

This paper described the design of an EM field generator system. The system consists of our newly built TEM cell, a transmitter, a power meter and an attenuator. It has an operating frequencies of 1-1000 MHz and characteristic impedance of 51 ohms. Its accurate measurable field strength is 1kV/m, with total uncertainty < +/- 1dB. It can be used to study to biomedical effects of EM fields.

Adaptation, Physiological↗

PubMed1998

[Inhibition effects of tumor infiltrating lymphocytes from oral cancer on nude mice transplanted tumor established with human tongue carcinoma cell lines].

OBJECTIVE: To observe the in vivo inhibition effects on nude mice transplanted tumor with tumor infiltrating lymphocytes (TILs) isolated from primary mass of oral cancer. METHODS: Established the transplanted tumor model of human tongue cancer at the back of BALB/C nude mice with subcutaneous injection of squamous cell carcinoma lines Tca 8113. TILs isolated from patients with Oral cancer, combining with low dose of cyclophosphamide (Cy: 50 mg/kg), were locally injected into the peripheral site of tumor. The inhibition rate (IR) was calculated by the volume of tumor mass from the 1st to the 8th week, and the weights at the 8th week after tumor dissection. RESULTS: 1. Group TIL + rIL-2 and group TIL + rIL-2 + Cy both exerted a strong inhibition effect on the transplanted tumor within three weeks. The Inhibition rate (IR) were 86.1% +/- 0.4% and 97.7% +/- 0.6% respectively at the 3rd week, while 32.1% +/- 0.3% and 80.6% +/- 0.3% at the 8th week. 2. TIL + rIL-2 + Cy expressed a stronger effect and a longer inhibition time. The IR of TIL + rIL-2 and TIL + rIL-2 + Cy were 20.0% +/- 1.4% and 75.5% +/- 2.5% respeetively at the 8th week (P < 0.01). CONCLUSION: This study demonstrated that TILs from patients with oral carcer possess strong in vivo inhibition on nude mice transplanted tumor, and low dose of cyclophasophamide can enhance the inhibition effect and prolong the inhibition time.

Animals↗

PubMed1998

[Effect of dentin inorganic material during dentin bond].

OBJECTIVE: In order to investigated the effect of dentin inorganic material during dentin bond. METHODS: This study investigated the tensile bond strength (TBS) between 4-META/MMA-TBB resin and dentin treated with several dentin treating methods. RESULTS: When the dentin was treated with acid-salt pretreating solution system (APSS) consisting of 10% citric acid and 3% ferric chloride to remove smear layer, and then re-treated with NaOCl to resolve dentin collagen and reveal dentin inorganic material, TBS of the dentin was 5.93 MPa, and higher than that of control group (3.71 Mpa) (P < 0.05) whose dentin was treated with distilled water only. CONCLUSION: It was suggested that dentin inorganic material did play a proper role in dentin bond.

Acrylic Resins↗

PubMed1998

[Effect of the pH value of acid-salt pretreating solution system on dentin-bonding strength].

OBJECTIVE: In order to investigate the mechanism of dentin bond promoted by acid-salt pretreating solution system (APSS). METHODS: The tensile bonding strength (TBS) of 4-META/MMA-TBB resin to the dentin, which was treated by acid and retreated by APSS with different pH value, was tested. RESULTS: The TBS of dentin rose gradually from 10.41 MPa to 15.73 MPa with the decreasing of the pH value of APSS. The metallic salt solution containing acid or not, apparently affected the TBS of dentin. CONCLUSION: This study showed that the form of metallic ion in APSS correlated with the TBS of dentin.

Acrylic Resins↗

PubMed1998

[Management of severe Budd-Chiari syndrome by spleen-internal jugular venous shunt].

OBJECTIVE: To study the operative method for severe Budd-Chiari syndrome. METHOD: 17 patients with severe Budd-Chiari syndrome were treated with splenectomy and spleen-internal jugular venous shunt. RESULT: Follow up for 3 to 20 months 11 patients showed excellent results, 5 good results and 1 died. CONCLUSION: Spleen-internal jugular shunt is effective for the patients with severe Budd-Chiari syndrome.

Adult↗