Biomedical subjects

X Zhao

Publications and source records attributed to X Zhao.

At least 577 records · Page 32Linked to original sources

PubMed1995

Morphologic observation of neutrophil diapedesis across bovine mammary gland epithelium in vitro.

Neutrophils are present in milk of cows as a means of suppressing invading pathogens during mastitis. However, the manner by which neutrophils traverse the secretory epithelia is still not clear: do they diapedese between epithelial cells or do they kill epithelial cells to gain entry into milk? We investigated the process of bovine neutrophil diapedesis across bovine mammary gland epithelium in vitro. The bovine mammary epithelial cell line MAC-T, grown on collagen-coated filters, formed a confluent monolayer with characteristic tight junctions, basal-apical polarity, and functional barriers to the dye trypan blue. Neutrophils added on the apical surface of the monolayer were stimulated to diapedese across the epithelium by the addition of Staphylococcus aureus (10(7) colony-forming units/ml) to the basal compartment. Light and transmission electron microscopy revealed the series of events for neutrophil transmigration: accumulation of neutrophils on the surface of epithelial monolayer; projection of pseudopods into intercellular junctions and movement of neutrophils between adjacent epithelial cells; and reapproximation of the lateral epithelial cell membranes and reformation of the apical tight junctions after neutrophils crossed the epithelium. Morphologically, epithelial cell damage caused by neutrophil diapedesis was not evident. This in vitro model provides a two-dimensional epithelial sheet by which neutrophil diapedesis can be qualitatively studied under defined conditions. Results of the study suggest a major mode by which bovine neutrophils diapedese across the alveolar epithelia into milk during mastitis.

Animals↗

PubMed1995

[Inhibition of glutamate uptake in rat brain synaptosome by pyrethroids].

In vitro studies showed deltamethrin (1 x 10(-7)-1 x 10(-4) mol/L) could inhibit 3H-DL-glutamate uptake in rat cerebral cortex and hippocampus synaptosome by 7.2%-21.5% and 10.4%-25.1%, respectively, with a dose-response pattern. But only in high-dose permethrin (1 x 10(-4) mol/L) can significantly reduce 3H-DL-glutamate uptake in rat hippocampus synaptosome. In addition, deltamethrin also can reduce 3H-DL-glutamate uptake in cerebellum and striatum of rats by 16.5% and 31.8%, respectively. It is suggested that both deltamethrin and permethrin, especially the former, can disturb the function of brain tissue in high-affinity-glutamate uptake with their alpha-cyano-group. So pyrethroids could play an important role in cerebral stimulation in mammals.

Animals↗

PubMed1995

A strategy for constructing high-resolution genetic maps of the human genome: a genetic map of chromosome 17p, ordered with meiotic breakpoint-mapping panels.

Genetic linkage analyses with genotypic data obtained from four CEPH reference families initially assigned 24 new PCR-based markers to chromosome 17 and located the markers at specific intervals of an existing genetic map of chromosome 17p. Each marker was additionally genotyped with an ordered set of obligate, phase-known recombinant chromosomes. The breakpoint-mapping panels for each family consisted of two parents, one sib with a nonrecombinant chromosome, and one or more sibs with obligate recombinant chromosomes. The relative order of markers was determined by sorting segregation patterns of new markers and ordered anchor markers and by minimizing double-recombination events. Consistency of segregation patterns with multiple flanking loci constituted support for order. A genetic map of chromosome 17p was completed with 39 markers in 23 clusters, with an average space of 3 cM between clusters. The collection of informative genotypes was highly efficient, requiring fivefold fewer genotypes than would be collected with all the CEPH families. Given the availability of large numbers of highly informative PCR-based markers, meiotic breakpoint mapping should facilitate construction of a human genomic map with 1-cM resolution.

Base Sequence↗

PubMed1995

Heightened inflammatory response and cytokine expression in vivo to cagA+ Helicobacter pylori strains.

BACKGROUND: Helicobacter pylori strains that possess the cytotoxin-associated gene (cagA) are highly associated with peptic ulcer disease, but the role of cagA in pathogenesis is unknown. EXPERIMENTAL DESIGN: To test the hypothesis that cagA+ stains elicit a greater proinflammatory cytokine response in the gastric mucosa than cagA- strains, gastric biopsies were obtained from 52 patients and studied by histology, culture, enzyme-linked immunosorbent assay, and reverse transcription polymerase chain reaction. RESULTS: Of 52 patients, 32 (62%) were infected with H. pylori based upon both serology and histology or culture, 16 (31%) were negative by serology, histology, and culture, and four (7%) were positive by serology only. Of 15 H. pylori-infected patients with peptic ulceration, 14 (92%) were infected with cagA+ strains compared with 8 (50%) of 16 patients with gastritis alone, and those infected with cagA+ strains had significantly higher grades of inflammation in the gastric mucosa. Antral inflammation score was significantly associated with IL-8 production. Antral biopsies from infected patients, compared with uninfected patients, significantly more often demonstrated IL-1 beta, IL-2, and IL-8 expression, and those infected with cagA+ compared with cagA- strains significantly more often expressed IL-1 alpha and IL-1 beta and showed elevated antral IL-8 protein levels. Similarly, patients with ulcer disease significantly more often expressed antral IL-1 alpha and IL-8 than those without ulceration. CONCLUSION: These results indicate that infection with cagA+ H. pylori strains is associated with higher grades of gastric inflammation, correlating with enhanced mucosal levels of IL-8, and increased risk of peptic ulceration.

Antigens, Bacterial↗

PubMed1995

[Construction and expression of the gene CD4V1V2-PE40, coding for a molecular targeted protein against AIDS].

We here replaced the cell-binding domain in Pseudomonas exotoxin A (PE) with HIV-binding portion of CD4V1V2 molecule and constructed a chimeric gene CD4V1V2-PE40, which can be expressed in E. coli. The hybrid protein displays targeting toxicity toward cells infected by HIV and thus represents a promising novel therapeutic agent for the treatment of AIDS.

ADP Ribose Transferases↗

PubMed1995

Cloning and expression of the gene coding for IL-2(60)-PE40, a molecular targeted protein.

It has recently been shown that chimeric toxin composed of IL2 fused tp PE40, a mutant form of Pseudomonas Exotoxin A devoid of its native cell recognition and binding domain was cytotoxic to IL2 receptor bearing cells. We here amplified the gene IL-2 (60), which codes for the N-terminal 1-60 amino acids of human IL-2 by PCR. After that, we fused it to PE40 and the new chimeric protein IL-2(60)-PE40 was expressed in E. coli. SDS-PAGE revealed that IL-2(60)-PE40 chimeric protein accounts for more than 18% of total cell proteins. As the region IL-2 binds with its receptor was defined in the N-terminal residues 8-54 of IL-2, such fusion proteins will have the same activity with IL-2-PE40. Following primary purification, IL-2(60)-PE40 was shown to be very toxic to IL-2 receptor-positive cells but non measurable effect on the cells lacking IL-2 receptors. Such a structure has not been reported by now. The fusion protein is useful for suppressing the immune response in cases of rejection of allografts and organ transplants and as therapeutic agents for the treatment of IL-2 receptor related diseases such as autoimmune disease, ATL (adult T-cell leukemia), et al.

Animals↗

PubMed1995

[Analytical study on drug-processing of the root of Glycyrrhiza uralensis Fisch. by HPLC].

This paper presents a study on the drug-processing of the root of Glycyrrhiza uralensis. A HPLC method for the determination of glycyrrhizic acid in Glycyrrhiza uralensis and its processed products has been established. The method is simple, specific and accurate. The recovery is 99.97% and the relative standard deviation is 0.9%.

Chromatography, High Pressure Liquid↗

PubMed1995

[Effects of copper needling therapy on cavernous hemangioma assessed by echogram].

Thirty-one patients with subcutaneous cavernous hemangioma were observed by echogram before and after treatment with copper needling. Different characteristics of echogram were found in hemangioma before and after treatment. Color Doppler imaging gave great help in the diagnosis and treatment of this disease and follow-up.

Adolescent↗

PubMed1995

[Cloning and sequencing of the gene PE40, coding for a portion of Pseudomonas exotoxin A].

Gene PE40 coding for a mutant form of Pseudomonas Exotoxin A was devoid of its native cell binding domain, and was amplified from the total DNA of P. aeruginosa PA103 by PCR. After being sequenced, it was cloned into expressional vector pBV220 to get a recombinant plasmid, which will be useful in the research of molecular targeted protein.

ADP Ribose Transferases↗

PubMed1995

[Photodynamic effect of HPD on DNA functions].

After treatment of the DNA by HPD and light the number of transformants of the M13mp8 DNA obviously decreased during the period of transforming the treated DNA into E coli. Meanwhile some of the mutation sequences appeared in the DNA which recovered from the DNA/HPD/Light transformant. It showed that the wrong replication happened because of the mutated template. Also the in vitro run-off transcription of IL-2R alpha gene was affected by HPD and light. It means that the DNA functions are influenced by the photodynamic effects.

Bacteriophage M13↗

PubMed1995

[Effect of HC-3 on electroacupuncture-induced immunoregulation].

Our previous study suggested that peripheral sympathetic nerve played an important role in the electroacupuncture (EA)-induced immunomodulation. The aim of this study is to explore the role of peripheral parasympathetic nerve in it. All mice are preimmunized with SRBC (sheep red blood cell) 4 days before experiment. The animals in different groups were injected i.p. with Hemicholine-3 (HC-3, an ACh synthesis blocker) or physiological saline 3 hr before EA. The main results are as follows: 1. In saline group, the LTT (lymphocyte transformation test), IL-2 (interleukin-2) of spleen and lymphocyte number of thymus are markedly increased, and the other immune parameters have no change after EA. 2. In HC-3 control group, the LTT, IL-2 are decreased significantly and the other immune parameters have not shown influence. 3. In the HC-3 with EA group, the magnitude of LTT, IL-2 did not significantly change as compared with HC-3 alone, it is especially noteworthy that the other unchanged parameters by HC-3 such as spleen weight, spleen index, thymus weight, thymus index, number of spleen cells, spleen LZM(lysozyme) and thymus LZM are clearly decreased after EA. The above results suggest that peripheral parasympathetic nerve may play some promoting effect in the EA-induced immunomodulation. Its effect may be mediated by ACh released from parasympathetic nerve endings.

Adjuvants, Immunologic↗

PubMed1995

[A study on the peripheral blood stem cells mobilization, collection and their effects on engraftment].

The methods of mobilization and collection of stem cells in peripheral blood stem cells transplantation (PBSCT) and the association between the number of stem cells transplanted and hematopoietic recovery were studied. The investigation was carried in 22 patients (11 acute leukemia, 6 multiple myeloma, 4 non-Hodgkin's lymphoma, 1 breast cancer). Three regimens for mobilization were carried out as follows: 1) chemotherapy + tetrahydrofolic acid + dexamethasone, 2) chemotherapy + rhGM-CSF + dexamethasone, 3) chemotherapy + rhG-CSF + dexamethasone. Besides, CD34/CD33 dual-color direct immunofluorescence flow cytometry assay was performed in 7 cases in the rhG-CSF group. The results showed: 1) The mean number of collected cells (MNC) in the rhG-CSF group was MNC (8.29 +/- 6.14) x 10(8)/kg and CFU-GM (21.35 +/- 17.24) x 10(4)/kg, being highest among the 3 groups. 2) The number of CD34+ cells correlated with MNC and CFU-GM. CD34+ cells in the peripheral blood were 0 or < 0.5% before mobilization and increased markedly 6-8 days after rhG-CSF administration. Harvesting should be started at that time and carried out every day until CD34+ cells reached 5 x 10(6)/kg. 3) The number of PBSC transplanted was the key to hematopoietic recovery.

Adolescent↗

PubMed1995

[Immunohistochemical study of hepatitis C virus (HCV) antigen in liver tissue of patients with HCV infection].

Hepatitis C virus antigen (HCV Ag) and HCV-NS3 protein in paraffin-embedded liver tissue of patients with HCV infection were detected with immunohistochemical method by using polyclonal anti-HCV and monoclonal anti-HCV-NS3 for studying the expression of HCV in liver tissue. The results showed that the detection rate of HCV Ag and HCV-NS3 were 38.3% and 30.0% respectively. All the specimens with HCV-NS3 positive tissue were also those with HCV Ag positive. The stained substance located in the cytoplasm of liver cell, and the stained cells distributed scattered, clustered or diffuse in liver lobular. No obvious infiltration or necrosis was observed around the positive cells. There was obvious difference of the detection rate between different models of serum HCV markers. These results provided some help in understanding the pathogenesis of HCV.

Adolescent↗

PubMed1995

[Effects of nasal continuous positive airway pressure on breathing pattern and respiratory drive in patients with obstructive sleep apnea syndrome].

To examine the influence of continuous positive airway pressure (CPAP) therapy on respiratory center drive in patients with obstructive sleep apnea syndrome (OSAS), 20 normocapnic OSAS patients (group 0) and 20 simple snoring patients were studied. In the first night, diagnostic polysomnography (PSG) was performed. Before and after PSG monitoring, mouth occlusion pressure (P0.1), tidal volume (VT), minute ventilation (VE), respiratory rate (RR), inspiratory time (Ti), expiratory time (Te), total cycle duration (Ttot), inspiratory duty cycle (Ti/Ttot), mean inspiratory flow (VT/Ti) and effective inspiratory impedance (P0.1/VT/Ti, Ieff) were measured while they were breathing room air. In the following night the OSAS patients were treated with nasal CPAP and PSG monitoring and the above mentioned measurements were repeated. The results showed that pre-PSG values of P0.1, RR and P0.1/VT/Ti in the OSAS patients were significantly higher than those in the snoring patients, while VT, Ti, Te and Ttot values were lower. In the first night, the post-PSG P0.1 value in the OSAS patients increased markedly as compared with the pre-PSG. After overnight nasal CPAP therapy, the respiratory disorder index in the OSAS patients decreased markedly, the nadir SaO2 increased markedly, but the post-PSG P0.1 value did not increase significantly. It is concluded that, before sleep, OSAS patients exhibit a higher respiratory drive and a shallow and frequent breathing pattern as compared with simple snoring patients. After nocturnal sleep, the respiratory drive of OSAS patients increases significantly, the breathing pattern becomes more shallow and frequent. Nasal CPAP may effectively relieve the sleep apnea and hypopnea as well as the resulting hypoxemia and therefore correct the changes in breathing pattern and respiratory drive through nocturnal sleep in patients with OSAS.

Adult↗

PubMed1995

[Risk of malignant changes in hydatidiform mole complicated with pregnancy induced hypertension].

OBJECTIVE: To investigate the prognosis of patients of hydatidiform mole (HM) who complicated with pregnancy induced hypertension (PIH) and to suggest that PIH may serve as a risk factor for malignant change in molar pregnancy. METHODS: From 1962 to 1992, 161 patients of HM including 33 cases with PIH and 128 cases of normotension were managed and followed at the PLA General Hospital. The definition of malignant sequelae was that abnormal hCG level was lasting at least 8 weeks after molar evacuation or metastatic lesions was found. RESULTS: 15 of 33 patients with PIH developed metastatic invasive moles (45.5%) and 13 of them metastatic tumors were found before molar evacuation. 12 of 128 cases of normotension had malignant thanges including 1 choriocarcinoma and 11 invasive mole (9.4%) and among them only one had metastatic lesions before molar evacuation. CONCLUSIONS: The incidence (45.5%) of malignant changes in patients complicated with PIH was significantly higher than that in normotensive patients (9.4%) (P < 0.01). In addition, they had early metastatic lesions. This study suggests that PIH may serve as a risk factor for malignant change in molar pregnancy.

Adult↗

PubMed1995

[Relationship between the fetal axis and dystocia in cephalic presenting deliveries].

OBJECTIVE: To study the relationship between the fetal axis and dystocia in cephalic presenting deliveries. METHODS: The fetal axis of the observed cases in their late pregnancy were measured by the method which was designed by anatomical projection. During labor the cases with abnormal fetal axis were divided randomly into control group and study group. The abnormal fetal axis in the study group was corrected by hand. RESULTS: The abnormal fetal axis existed in 108 of 512 (21.1%) cases in late pregnancy and were divided into different degrees. The rate of severe degree was 51.8%. During labor 88 of 483 (18.2%) cases were severe degree. They were sub-divided into control group (30 cases) and study group (58 cases). The results showed: in the study group the descent of fetal-presentation was accelerated, the stage of labor became shorter, the incidence of persistent occipito-posterior or occipito-transverse position and operative delivery were decreased, and the postpartum hemorrhage out down also. CONCLUSIONS: The abnormality of fetal axis exists and it can affect the progress of labor. The abnormal fetal axis should be diagnosed and corrected in time. To some extent, it can reduce the mother's physical consumption in labor and decrease the incidence of dystocia.

Delivery, Obstetric↗

PubMed1995

[Effect of acupuncture on the contents of enkephalins in different brain regions of rats with traumatic shock].

The study was carried out on the animal model of traumatic shock which induced by ligating bilateral hind legs. The contents of enkephalins in hippocampus, striatum, hypothalamus, diencephalon and brain stem were determined with radioimmunoassay. The results show that: (1) when traumatic shock occurs, the contents of Met-enkephalin are not obvious change in the above 5 brain regions, and also not significant change after acupuncture; (2) there is a tendency to increase the content of Leu-enkephalin in each brain region described above of shock animal, while it is decreased in hypothalamus after acupuncture. The result suggests that the occurrence of traumatic shock may be related to the functional activities of Leu-enkephalinergic system in the central nervous system; the anti-shock of acupuncture may be through a decrease in the level of central Leu-enkephalin to improve micro-circulation and raise the blood pressure.

Animals↗

PubMed1995

[Study on expression and regulation of atrial natriuretic factor (ANF) gene in nasal mucosa].

Using 32P labelled rat ANF cDNA probe, the ANF gene transcripts in rat nasal mucosa and the effect of glucocorticoid and estrogen on the ANF gene transcripts was examined by Dot blot and Northern blot hybridization. Further more, the gene expression of ANF in nasal mucosa tissues of some patients with nasal diseases were also examined. The results showed that nasal mucosa contained ANF mRNA which could synthesize ANF. Both estrogen and glucocorticoid could enhance ANF gene expression in nasal mucosa with dose dependance. The gene expression of ANF in nasal polyps and inferior turbinate mucosa of patients with nasal polyps was more evident than that in other pathological conditions. The clinical significance of ANF in nasal mucosa was also discussed.

Adolescent↗