Biomedical subjects

Y Chen

Publications and source records attributed to Y Chen.

At least 613 records · Page 34Linked to original sources

PubMed2001

Gynecological procedures under gasless laparoscopy.

OBJECTIVE: To evaluate gasless laparoscopy in treating gynecological conditions. METHODS: With Kirschner wire lifting, transversely or longitudinally introduced into abdominal wall subcutaneously, we exposed the operative field and pelvic organs with routine operative instruments under epidural anesthesia. When a dense pelvic adhesion was confronted, we used the temporarily low-pressured pneumolaparoscopy to dissect it. RESULTS: All procedures were carried out without organ injury, hematoma, or other complications. The operative field can be clearly seen with this method. The mean time for appendagectomy was one hour and for laparoscopic assisted vaginal hysterectomy 80 minutes. CONCLUSION: Gasless laparoscopy avoids the complications which occur in the routine laparoscopy such as subcutaneous or mediastinal pneumatoma, hypercarbonemia, air embolism, cardiopulmonary dysfunction. Our lifting method is simple, convenient, time and money saving, as well as more flexible for treating gynecological conditions.

Adult↗

PubMed2001

Detailed deletion mapping on chromosome region 9p21 in human periampullary neoplasms.

OBJECTIVE: To further define the extent of chromosome 9p21 deletion in periampullary neoplasms. METHODS: The loss of heterozygosity at 5 microsatellite polymorphic markers on chromosome 9p21 was detected by polymerase chain reaction (PCR), polyacrylamide gel electrophoresis (PAGE) and silver staining in 35 specimens of periampullary neoplasms and their matching blood samples. RESULTS: Fifty percent (4/8) of pancreatic cancer cases showed the loss of heterozygosity at one or more microsatellite loci, with the more frequent sites of D9S974 (37.5%) and D9S942 (28.6%), and some showing consecutive allelic loss. Sixty-two point five percent (5/8) of ampullary carcinoma cases showed loss of heterozygosity at one or more of the loci, frequent site of loss being D9S942 (42.9%) and the next most frequent being IFNA (37.5%) and D9S171 (37.5%). Loss of one locus was observed in 14.2% (1/7) of insulinoma. CONCLUSION: The minimal common region of chromosome deletion in periampullary neoplasms is defined between the D9S974 and D9S942 loci within a 15 kb interval in 9p21, suggesting the involvement of a novel tumor suppressor gene in their carcinogenesis.

Adolescent↗

PubMed2001

Genetic analysis of wild-type hepatitis A virus strains.

OBJECTIVE: To clarify the distribution of hepatitis A virus (HAV) genotype in geographical regions of China. METHODS: Seventeen representative HAV strains were isolated from the stool or serum of hepatitis A patients in different geographical regions. Viral RNA was recovered from stool or serum by proteinase K digestion and phenol-chloroform extraction, followed by ethanol precipitation prior to reverse transcription and polymerase chain reaction (RT-PCR) amplification. The nucleotide sequences of VP1/2A junction region were tested by using a direct sequencing technique. RESULTS: A pairwise comparison of sequences within 168 bases at the VP1/2A junction revealed that all the sequences clustered within genotype I. About 53% of strains clustered in genotype I B, with less than 6% variability; while the others clustered in genotype I A, with less than 5.3% variability. Sequence homology between genotype I A and I B varied from 88.7% to 92.3%. CONCLUSION: Epidemic or sporadic HAV strains in China may belong to HAV genotype I A or I B. Epidemiologically related strains may be identical or closely related in sequence.

Genotype↗

PubMed2001

[Study on the intestinal microbial colonization resistance in patients with chronic severe hepatitis].

OBJECTIVE: To investigate the changes of microbial colonization resistance of the bowel in patients with chronic severe hepatitis. METHODS: The fecal flora bifidobacteria, enterobacteriaceae, enterococci, and yeasts of subjects (chronic severe hepatitis, chronic hepatitis, and healthy volunteers) were quantitatively and qualitatively analyzed by Mitsuoka's methods. While the ratio of bifidobacterium to enterobacteriaceae ( B/E ratio ) was calculated. RESULTS: The number of bifidobacteria and the B/E ratio in chronic severe hepatitis group was significantly deceased compared with that of the control group (P<0.001). The number of enterobacteriaceae and yeasts was significantly increased compared with that of control group (P<0.001 and P<0.01, respectively). CONCLUSIONS: The results suggest that the intestinal microbial colonization resistance in patients with chronic severe hepatitis is seriously impaired.

Bifidobacterium↗

PubMed2001

[p53 and vascular endothelial growth factor expression in astrocytoma and their relation to angiogenesis].

OBJECTIVE: This investigation was done to show the pathological importance of p53 protein detection, vascular endothelial growth factor expression (VEGF) and intratumoral microvessel density (IMVD) in astrocytoma. METHODS: The surgical specimens from 60 brain astrocytoma patients were stained immunohistochemically for p53 and IMVD expressions. IMVD was calculated by labeling the endothelial cells of the blood vessels within the tumor. RESULTS: p53, VEGF expression were closely correlated with histopathological grade of astrocytoma. Positive p53 protein accumulation and VEGF expression were found in 45.0% (27/60) and 65.0% (39/60) of tumors. The conformation rate of p53 and VEGF was 70.0% (42/60). IMVD was significantly higher in the p53-positive or VEGF-positive tumors than in the negative ones (P < 0.05). Comparing the IMVD in p53+/VEGF+ group, p53-/VEGF+ group and p53+/VEGF- group, p53-/VEGF- group, its difference was also highly significant (P < 0.05). CONCLUSION: (1) p53 protein detection, VEGF expression and IMVD can be considered as a biological indicator of malignant potential in brain astrocytoma patients and (2) p53 and VEGF expressions, both contributing to the tumor neovascularization, may be helpful in the understanding of intra-tumoral angiogenetic mechanism in the future.

Adolescent↗

PubMed2001

[Combining transvaginal sonography and endometrial cytology in the diagnosis of endometrial disorders in postmenopausal women].

OBJECTIVE: To evaluate the combined use of transvaginal sonography and endometrial cytology for the diagnosis of endometrial disorders in postmenopausal women. METHODS: One hundred forty-three patients with postmenopausal uterine bleeding were studied prospectively. Transvaginal sonography was used to measure the endometrial thickness (double layers), followed by use of the ori endometrial sampler. The results were compared to the histopathologic diagnosis of specimens obtained by dilatation and curettage. RESULTS: When the cutoff point of endometrial thickness was set at 5 mm to detect endometrial malignancy and premalignancy, transvaginal sonography showed a 100.0% sensitivity and 56.9% false positive rate. Endometrial cytology showed a 96.3% specificity but it had a 2.5% false negative rate. The combined use of transvaginal sonography and endometrial cytology can decrease false positive rate of transvaginal sonography from 56.9% to 43.2% (P < 0.01). CONCLUSION: The combined use of transvaginal sonography and endometrial cytology is a good method to screen endometrial malignancy and premalignancy.

Adult↗

PubMed2001

[Effects of ovulation induction on expression of integrins alpha 4 beta 1 in endometrium].

OBJECTIVE: To study the effect of clomiphene citrate (CC) and human menopausal gonadotropin (hMG) on the expression of integrins alpha 4 beta 1 during implantation window in endometrium. METHODS: Endometrium integrin alpha 4 beta 1 expression was detected by immunohistochemistry method in the mid-secretory phase of 48 normal natural cycles. CC + hCG or CC + hMG + hCG cycles in 30 polycystic ovary syndrome (PCOS) patients and 48 normal women. RESULTS: The expression of endometrial integrin alpha 4 beta 1 was stronger in the natural cycles than those of ovulation induction cycles with CC + hCG or CC + hMG + hCG. So was the pregnancy cycles as compared with the non-pregnant cycles. CONCLUSION: The endometrial receptivity in the min luteal phase and pregnant rate declined during ovulation induction by CC + hCG or CC + hMG + hCG in either normal women or PCOS patients.

Adult↗

PubMed2001

Effect of L929 cell-conditioned medium on antioxidant capacity in RAW264.7 cells.

Previously, we found that macrophage colony-stimulating factor (M-CSF) could reduce tert-butyl hydroperoxide (tbOOH)-induced oxidative injury in monocytes/macrophages. In order to find the mechanism by which M-CSF achieves this, we investigate the effect of M-CSF on the antioxidant system in murine macrophage RAW264.7 cells, using L929 cell-conditioned medium (L929-CM) as the source of M-CSF. The results show that L929-CM increased selenium-dependent glutathione peroxidase, non-selenium-dependent glutathione peroxidase, and catalase activities; and it increased reduced glutathione (GSH) but decreased lipoperoxide content in RAW264.7 cells. L929-CM-treated cells maintained their antioxidant capacity (including antioxidant enzyme activities and GSH content) when challenged with tbOOH. We conclude that M-CSF from L929-CM reduces oxidative injury in RAW264.7 cells by increasing antioxidant enzyme activity and improving redox status.

Animals↗

PubMed2001

Analysis of the T cell receptor V delta region gene repertoire in bronchoalveolar lavage fluid (BALF) and peripheral blood of asthmatics.

OBJECTIVE: To explore the role of gamma delta T cells in the airway of asthmatics and to identify the forces which induce and maintain the inflammatory process. METHODS: Peripheral blood (PB) and bronchoalveolar lavage fluid (BALF) were obtained from 7 asthmatic subjects and 7 nonsmoker control subjects. The percentage of gamma delta T cells in the PB and BALF was measured by immunofluorescent staining and flow cytometry. The frequency of usage and the clonality of V delta subfamilies (V delta 1-V delta 3) were assessed by RT-PCR and gene scanning. RESULTS: A higher proportion of gamma delta T cell was detected in the BALF of asthmatic subjects (7.8% +/- 4.7%) than that from control subjects (3.3% +/- 3.0%, P = 0.04). No selective usage for a particular V delta subfamily was found, but the relative expression level of V delta 1 was significantly higher in the asthmatic airway (44% +/- 13%) than in the control (19% +/- 5%, P = 0.0002). In asthmatic subjects, the monoclonal or oligoclonal expansion of gamma delta T lymphocytes was predominant in the BALF, especially V delta 1+ T lymphocytes. CONCLUSIONS: Antigenic specific gamma delta T cells might play an important role in the inducement and maintenance of airway inflammation. Persistent antigenic stimulation may be the key factor that maintains chronic airway inflammation in asthma.

Adult↗

PubMed2001

Role of beta-adrenoceptor at different stages of bronchial asthma.

OBJECTIVE: To investigate the changes of beta-adrenergic receptor (beta AR) in peripheral lymphocytes and beta 2AR mRNA levels at different stages of bronchial asthma. METHODS: beta 2AR density and beta 2AR mRNA level in peripheral lymphocytes, cAMP and cGMP levels in blood plasma were estimated by radioligand binding assay, radioimmunoassay and RT-PCR. RESULTS: (1) Maximum bound volume (Bmax) and equilibrium dissociation constant (Kd) of beta 2AR of lymphocyte in asthma patients at remission stage were markedly higher than that in normal subjects, while cAMP levels in blood plasma showed no difference. Bmax of beta 2AR and cAMP levels in asthma patients at acute exacerbation stage were significantly lower than that in normal subjects, and Kds between these two groups were not much different. (2) Expression of beta 2ARmRNA in peripheral lymphocytes of asthmatics at remission stage was not significantly different compared with that in normals. CONCLUSIONS: Amount and function of beta AR and beta 2ARmRNA levels are related to asthmatic conditions. Changes of beta AR and beta 2ARmRNA in asthma might rather be a pathological change accompanied by the course of the disease than a primary defect.

Adult↗

PubMed2001

[A study on the pathogenesis of Streptococcus mitis exotoxin].

OBJECTIVE: To study the isolation, purification and pathogenesis of Streptococcus mitis pyrogenic exotoxin causing toxic shock syndrome. METHODS: Streptococcus mitis isolated from patients' throat were shaking cultivated. After being centrifuged, the supernatant fluid of the culture was precipitated with 20%, 40%, 60%, 80% (NH(4))(2)SO(4) respectively and the fast protein liquid chromatography(FPLC) was used for the final step of purification. Rabbits receiving subcutaneous injection with respective purified proteins were monitored daily for fever. The ability of the purified proteins to enhance the susceptibility of the rabbits to lethal Escherichia coli endotoxin shock is recorded, when the endotoxin was injected intravenously 4 hours after administration of 10 microg Streptococcus mitis exotoxin. RESULTS: Only the protein precipitated by 20% (NH(4))(2)SO(4) (molecular weight is 34,000) from culture supernatant fluid was pyrogenic for rabbits (average temperature increase near 1 degrees C), and it can also cause the proliferation of rabbit splenocytes (mitogenicity). All the animals receiving subcutaneous injection of exotoxin containing purified proteins precipitated with higher concentrations of (NH(4))(2)SO(4) died within 16 approximately 29 hours after intravenous injection of the Escherichia coli endotoxin, demonstrating the enhanced susceptibility of the animals to lethal endotoxin shock. The control rabbits displayed none of these effects. CONCLUSION: Streptococcus mitis exotoxin is a novel streptococcal pyrogenic exotoxin.

Animals↗

PubMed2001

[The mechanism of somatostatin-induced acid secretion inhibition in isolated parietal cells].

OBJECTIVE: So far five different somatostatin receptor(SSR) subtypes have been characterized. Somatostatin has been reported to inhibit acid secretion in vivo, but which subtype of the receptor mediate acid secretion in rabbit is unclear. The aim of this study is to identify which subtype mediates inhibition of acid secretion and to observe the effects of somatostatin and its selective agonists on histamine-stimulated acid secretion by(14)C-aminopyrine((14)C-AP) accumulation. METHODS: The effect of SS-14 and other receptor subtype agonists on histamine-stimulated acid secretion was studied with(14)C-AP accumulation in pure parietal cells. To identify SSR on parietal cells, positive SSR-specific primers by reverse transcription polymerase chain reaction (RT-PCR) and its probe by in situ hybridization (ISH) were used. RESULTS: (1) SS-14, sandostatin and SSR2 specific agonist NC8-12 (10(-9)-10(-7) mol/L) significantly inhibited histamine-stimulated (10(-6)) mol/L) acid secretion (P < 0.01), but SSR3 and SSR4 specific agonists had no inhibitory effects on histamine-stimulated acid secretion at the same concentrations(P > 0.05). (2) SSR2 gene expression in parietal cell was demonstrated with both RT-PCR and ISH method. CONCLUSION: The authors verified for the first time that SSR2 mediates the inhibition of histamine-induced acid secretion in parietal cell, and that SSR2 is present on parietal cells.

Animals↗

PubMed2001

[Thin basement membrane nephropathy: a mutation in COL4A5 gene].

OBJECTIVE: To investigate the mutations in COL4A5 in 3 X-linked thin basement membrane nephropathy families. METHODS: PCR-SSCP analysis were used for 51 exons of COL4A5 gene. If bands shift were found, then automated sequencing was performed after cloning in pGEM-T easy vectors. RESULTS: In one of the three families a glycine to alanine substitution was identified in the collagenous region of the COL4A5 gene, and the mutation cosegregates with hematuria in this family. CONCLUSION: Some of thin basement membrane nephropathy may be due to mutation of COL4A5 gene.

Adolescent↗

PubMed2001

[The effect of bombesin on cyclin D1/CDK4 of immortalized human gastric epithelial cell line].

OBJECTIVE: To investigate the regulatory effect of bombesin on the growth of immortalized human gastric epithelial cell line GES-1, as well as on the cell cycle-regulating elements cyclin D1 and CDK4. METHODS: GES-1 cells were treated with bombesin, alone or together with an bombesin antagonist. The growth effect was evaluated by MTT method, cyclin D1 expression by flow cytometry, CDK4 expression by Western blot plus enhanced chemoluminescence and CDK4 activity by immunoprecipitation with antibody-coated Sepharose beads. RESULTS: Bombesin at 10(-7) mol/L significantly stimulated the growth of GES-1 cells, increased cyclin D1 expression which was inhibited by bombesin antagonist. Bombesin also increased CDK4 protein expression and CDK4 activity. CONCLUSION: In an immortalized human gastric epithelial cell line, bombesin promotes cell cycle progression via an increase in the expression of cyclin D1/CDK4 and CDK4 activity.

Bombesin↗

PubMed2001

[Sequencing of inhA in drug-resistant Mycobacterium tuberculosis isolates].

OBJECTIVE: To determine and characterize inhA mutations of drug-resistant isolates of Mycobacterium tuberculosis. METHODS: PCR products of inhA of drug-resistant and susceptible isolates and H(37)R(v) were purified, cloned and analyzed by ABI 377 auto-DNA sequencing system. RESULTS: 11 out of 17 drug-resistant M. Tuberculosis isolates were detected having inhA variations. 10 out of the 11 strains with variations had at least one missense mutation. The variations consisted of point mutation (transition, transversion and deletion). Molecular mechanisms were different from strain to strain. 8 of 13 (62%) strains had both katG and inhA mutations. 18 variation positions and mechanisms different from previous report have been described. CONCLUSION: These results suggested that binding sites decrease caused by inhA point mutations be associated with M. tuberculosis' resistance to INH and EMB.

Amino Acid Sequence↗

PubMed2001

[In vitro study of the anti-pneumocystis carinii effect of arteminsin derivatives].

OBJECTIVE: In vitro study was carried out to assess the effect of dihydroarteminsinin (DHA) and sodium artesunate (ATS) on pneumocystis carinii (Pc). METHODS: The drugs were added into HepG-2 cell cultures containing Pc cysts. The concentrations of dihydroarteminsinin (DHA) were 100, 50, 10, 5, 0.5 micromol/L respectively. The concentrations of sodium artesunate (ATS) were 100, 50, 10, 5 micromol/L respectively and pentamidine (PTD) was 15 micromol/L as a control. The supernatants were withdrawn every other day and evaluated for Pc trophozoite and cyst counts by GMS and DQ stain. RESULTS: The peak of Pc multiplication was observed on 5th day. The inhibition rates of Pc trophozoites by DHA 50 micromol/L, 100 micromol/L and ATS 100 micromol/L were quite similar to that of pentamidine (PTD) 15 micromol/L. CONCLUSION: DHA and ATS can inhibit the growth of Pc as same as PTD, and DHA was slightly better than ATS.

Animals↗

PubMed2001

[Effect of thrombopoietin II on exsanguine thrombocytopenia mouse death rate].

OBJECTIVE: To study the effect of thrombopoietin II (TPO II) on the exsanguine thrombocytopenia mouse death rate. METHODS: After the normal peripheral platelet counts were done on the samples obtained from the tail vein of purebred Babl/c mice before experiment, the purified ligand I of TPO II, artificial compound ligand II of TPO II and rhTPO were injected intraperitoneally once a day for 7 days. On d 7 and d 14, platelet counts were performed on 0.5 ml samples obtained from the supra-orbital vein, with the condition of the mouse death monitored daily. RESULTS: On d 7, ligand I of TPO II group platelet counts were higher than that of the negative control group (P < 0.05), while not being significantly different from that of rhTPO group (P > 0.05). On d 14, the platelet counts of two TPO II groups increased significantly as compared with the negative control group (P < 0.01), showing no significant difference from that of rhTPO group (P > 0.05). Moreover, the platelet counts of mice in two TPO II groups and the positive group had shown an increasing tendency in the days following experiment. In addition, mouse death occurred in all groups of mice following their phlebotomy from the supraorbital vein on d 7. But the death rate of negative control group was evidently higher than that of any other groups (P < 0.05). CONCLUSION: TPO II's biological activity obviously increases platelet production, thereby reducing the exsanguine thrombopenia mouse death rate.

Animals↗

PubMed2001

[An epidemiological study on the risk factors of irritable bowel syndrome in Zhanjiang, Guangdong province].

OBJECTIVE: To assess the risk factors in the pathogenicity of irritable bouel syndrome(IBS) in Zhanjiang city. METHODS: Two hundred and seven IBS patients were randomly selected and compared with "healthy" people diagnosed in the same hospital during the same period. Roles of major risk factors to IBS were studied through using a case-control study. RESULTS: Family history of hysteria or mental disease and vegetorsis was closely related to IBS, with ORs 3 and 4 respectively. There was alse close relationship between IBS and psychic trauma, often taking antibiotics, tension at work and eating sweet potato or cassava, with ORs between 1 and 2. CONCLUSION: Our investigation suggested that the six major risk factors mentioned above played important roles in the progression of IBS in Zhanjiang city.

Case-Control Studies↗