Biomedical subjects

Y Gao

Publications and source records attributed to Y Gao.

At least 163 records · Page 9Linked to original sources

PubMed2000

Involvement of cGMP-dependent protein kinase in the relaxation of ovine pulmonary arteries to cGMP and cAMP.

Agonist-induced smooth muscle relaxation occurs following an increase in intracellular concentrations of cGMP or cAMP. However, the role of protein kinase G (PKG) and/or protein kinase A (PKA) in cGMP- or cAMP-mediated pulmonary vasodilation is not clearly elucidated. In this study, we examined the relaxation responses of isolated pulmonary arteries of lambs (age = 10 +/- 1 days), preconstricted with endothelin-1, to increasing concentrations of 8-bromo-cGMP (8-BrcGMP) or 8-BrcAMP (cell-permeable analogs), in the presence or absence of Rp-8-beta-phenyl-1,N(2)-etheno-bromoguanosine cyclic monosphordthioate (Rp-8-PET-BrcGMPS) or KT-5720, selective inhibitors of PKG and PKA, respectively. When examined for specificity, Rp-8-Br-PET-cGMPS abolished PKG, but not PKA, activity in pulmonary arterial extracts, whereas KT-5720 inhibited PKA activity only. 8-BrcGMP-induced relaxation was inhibited by the PKG inhibitor only, whereas 8-BrcAMP-induced relaxation was inhibited by both inhibitors. A nearly fourfold higher concentration of cAMP than cGMP was required to relax arteries by 50% and to activate PKG by 50%. Our results demonstrate that relaxation of pulmonary arteries is more sensitive to cGMP than cAMP and that PKG plays an important role in both cGMP- and cAMP-mediated relaxation.

Animals↗

PubMed2000

Maturational changes in endothelium-derived nitric oxide-mediated relaxation of ovine pulmonary arteries.

Endothelium-derived nitric oxide (EDNO) modulates the responses of pulmonary vasculature. The present study was designed to determine EDNO-mediated responses of pulmonary arteries (PA) of term fetal, newborn, and adult sheep. Vessel rings were suspended in organ chambers and their isometric tension was recorded. In vessels preconstricted with endothelin-1, acetylcholine had no effect on fetal PA but caused a greater endothelium-dependent relaxation in adult PA than in newborn PA. In vessels without endothelium, nitric oxide and 8-bromo-cGMP caused greater relaxation in adult PA than in newborn PA while causing the least relaxation in fetal PA. Acetylcholine had no effect on cGMP content in fetal PA but caused a greater endothelium-dependent increase in cGMP content in adult PA than in newborn PA. In vessels without endothelium, nitric oxide caused a smaller increase in cGMP content of fetal PA than of newborn PA while causing the greatest increase in cGMP of adult PA. These results demonstrate an age-dependent increase in EDNO-mediated responses of ovine pulmonary arteries. A change in receptor and/or receptor coupling, in soluble guanylate cyclase activity, and in cGMP responsiveness of vascular smooth muscle may contribute to the phenomenon.

Acetylcholine↗

PubMed2000

Inhibition of ubiquitin-proteasome pathway-mediated I kappa B alpha degradation by a naturally occurring antibacterial peptide.

Induction of NF-kappaB-dependent gene expression plays an important role in a number of biological processes including inflammation and ischemia-reperfusion injury. However, few attempts aimed at selective regulation of this transcription factor have been successful. We report here that a naturally occurring antibacterial peptide PR39 reversibly binds to the alpha 7 subunit of the 26S proteasome and blocks degradation of NF-kappa B inhibitor I kappa B alpha by the ubiquitin-proteasome pathway without affecting overall proteasome activity. I kappa B alpha phosphorylation and ubiquitination occur normally after PR39 treatment, and binding of valosin-containing proteins is not impaired. The inhibition of I kappa B alpha degradation abolishes induction of NF-kappa B-dependent gene expression in cell culture and in mouse models of acute pancreatitis and myocardial infarction, including upregulation of endothelial adhesion proteins VCAM-1 and ICAM-1. In the latter model, sustained infusion of PR39 peptide resulted in significant reduction of myocardial infarct size. PR39 and related peptides may provide novel means to regulate cellular function and to control of NF-kappa B-dependent gene expression for therapeutic purposes.

Animals↗

PubMed2000

Immediate post-abortal insertion of the frameless GyneFix IUD: initial experience in China.

The promising results obtained with the frameless GyneFix IUD for interval insertion led to the belief that the technology could be useful for immediate post-abortal application to reduce the number of induced and repeat abortions. IUDs have many advantages and the method is acceptable and safe. However, side effects and expulsion of conventional IUDs remain a problem. In an attempt to minimise these problems, the frameless GyneFix IUD was developed. Clinical studies conducted over the past 14 years have shown that the principles on which the device is based are valid. An increasing bulk of clinical evidence shows that the design characteristics of the device (fixed, frameless and flexible) are responsible for the low expulsion, high effectiveness, and high tolerance and continuation rates.1 Experience with the frameless IUD in China since 1989 confirms the international experience with the device. The present communication is a second report from China with the GyneFix IUD. In the present study the GyneFix IUD is inserted immediately following termination of pregnancy of less than 10 weeks amenorrhea. It is concluded that immediate post-abortal insertion of the frameless IUD is easy and safe, and appears to be as reliable and as effective as when it is inserted at interval. The GyneFix IUD could, therefore, constitute an important new option in the prevention of abortion.

Abortion, Induced↗

PubMed2000

The relationship between angiotensinogen gene CD235 met-->Thr substitution polymorphism and brain infarction in Chinese.

OBJECTIVE: To detect the relationship between angiotensinogen (AGT) gene CD235 Met-->Thr substitution polymorphism and brain infarction. METHODS: The CD235Met-->Thr substitution polymorphism in exon 2 of AGT gene was analyzed in normal group(82 cases) and brain infarction group (102 cases) by a combination of polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP). RESULTS: Between the control group and brain infarction group, chi-square test showed no significant difference in the frequencies of T/T genotype and T allele (P>0.05). However, the frequencies of T/T genotype and T allele (70.6% and 83.8%) for multiple brain infarction patients were higher than those (42.6% and 65.2%) for lacunae brain infarction patients and those (42.0% and 65.2%) for controls (P<0.01). The frequencies of AGT T/T genotype and T allele (65.3% and 78.6%) for patients with brain infarction associated with hypertension were higher than those (42.0% and 65.0%) for patients with brain infarction not associated with hypertension (P<0.05). CONCLUSION: No direct relationship between AGT CD235 Met-->Thr substitution polymorphism and ordinary brain infarction has been observed, but there is a significant correlation between AGT gene T/T genotype and multiple brain infarction, and brain infarction associated with hypertension too.

Adult↗

PubMed2000

CD40 ligand expression on macrophages during peritonitis in continuous ambulatory peritoneal dialysis patients.

CD40-CD40 ligand (CD40L) interaction plays an important role in macrophage/monocyte-mediated inflammatory processes by up-regulating cytokine production by macrophages/monocytes and by preventing macrophage apoptosis at the inflammation sites. The present study investigated the possible regulation of CD40L expression in peritonitis during continuous ambulatory peritoneal dialysis (CAPD). We used fluorescence-activated cell sorter (FACS) analysis to detect CD40L expression on macrophages obtained from peritoneal dialysate. Our results showed that CD40L expression on macrophages was significantly increased in a peritonitis group (4.62 +/- 6.54) as compared to a control group (0.76 +/- 0.30, p < 0.01). The CD40L-positive cells were also significantly increased during peritonitis (97.86% +/- 1.67% in the peritonitis group as compared to 73.10% +/- 26.94% in the control group, p < 0.05). After successful treatment, the expression of CD40L was significantly reduced (3.66 +/- 1.12 vs 1.05 +/- 0.02, p < 0.05). We conclude that functionally expressed CD40L on macrophages may take part in acute inflammatory response during peritonitis in CAPD and may play an important role in the local defense against infection in the peritoneal cavity.

Acute Disease↗

PubMed2000

Alteration of Fas/FasL expression of oral squamous cell carcinoma cell line Tca83 induced by retinoic acid.

OBJECTIVE: To elucidate the chemosensitivity of human tongue squamous cell carcinoma Tca83 cell line to all-trans retinoid acid (RA) and to determine the potential genetic factors mediating this sensitivity. METHODS: RA in the amounts of 0.1, 1, and 10 microMol/L were used to treat human cell line Tca83 in vitro. Cell apoptosis as well as Fas/FasL expression were analyzed by TUNEL, RT-PCR, and immunohistochemistry approaches. RESULTS: RA in the amounts of 1 and 10 microMol/L RA began to inhibit cell proliferation at day 3 and had induced cell apoptosis on day 5. Both Fas and FasL could be detected in the treated and untreated cells. RA upregulated Fas mRNA and protein expression at day 5. RA had no obvious effect on FasL expression. CONCLUSION: The results suggest that apoptosis induced by RA may result from the enhancement of Fas gene transcription and translation.

Antigens, Surface↗

PubMed2000

[The orthognathic treatment of developmental mandibular asymmetry].

OBJECTIVE: To explore the methods of orthognathic treatment for the developmental mandibular asymmetry to simultaneously achieve satisfactory facial appearance and oral functions and to prevent recurrence of the deformity. METHODS: 37 cases of developmental mandibular asymmetry have been treated in past seven years. The type of the deformity, the management of the cases, and the effects of therapy were summarized in this paper. RESULTS: According to the type of the asymmetric deformity, different means were used. After treatment, all the patients obtained satisfactory facial appearance and oral function. CONCLUSIONS: During the orthognathic treatment, it is important to simultaneously ameliorate facial appearance and achieve good oral function. It should be diagnosed before surgery whether the development of the deformity is steady or not. The correction of skeleton and soft tissues must be performed by stages.

Adolescent↗

PubMed2000

Huperzine A reverses scopolamine- and muscimol-induced memory deficits in chick.

AIM: To study the effects of huperzine A on disruption of spatial memory induced by scopolamine (a muscarinic antagonist) and muscimol (a GABAA agonist) in passive avoidance task. METHODS: One-trial passive avoidance task was used to investigate the effects of huperzine A. The avoidance rate was used to evaluate memory retention. RESULTS: Both scopolamine (100 ng) and muscimol (50 ng), injected intracranially 5 min before training, resulted in a decreased avoidance rate. Huperzine A (25 ng), injected intracranially 15 min before training, reversed memory deficits induced by scopolamine and muscimol at 30 min after training, and this reversal persisted at least 1 h. The improving effects of huperzine A exhibited a bell-shaped dose-response curve. CONCLUSION: Huperzine A improved the process of memory formation not only by acting as a highly potent and selective inhibitor of AChE, but also by antagonizing effects mediated through the GABAA receptor.

Alkaloids↗

PubMed2000

[Biological purification of saline chemical wastewater and variation of algological indicatiors].

Simulation pond experiment shows that from the entrance to the exit of the pond, the concentration of pollutants was decreased, while the species, diversity index and primary productivity of algae were gradually increased with increasing purification duration. The dominant algae species changed from high tolerance species to medium tolerant species. Algae quantity and chlorophyll-a concentration remarkably increased. Through 32 days, the purified water flowed out from the third grade pond. The relationships between algae quantity, biomass and chlorophyll-a concentration and the contents of BOD5, COD, NH3-N and PO4-P could be described with the second order equation. Temperature had an obvious effect on the algae growth and purification effectiveness. The optimum temperature condition for algae growth and wastewater purification was in the range of 20-25 degrees C.

Biomass↗

PubMed2000

[Place of value of pelvic lymphadenectomy for treatment of endometrial neoplasms].

OBJECTIVE: To explore the therapeutic value of pelvic lymphadenectomy for endometrial carcinoma. METHODS: One hundred and four cases undergoing pelvic lymphadenectomy were analyzed. Comparisons were carried out between various clinicopathologic factors and incidence of positive node, between 5 years survival rate with pelvic lymphadenectomy and that without pelvic lymphadenectomy. RESULTS: Four point four per cent case with positive node was found in clinical stage I cases. Positive node rate increased with deep myoinvasion and G3, accounting for 37.3% and 37.8% respectively. For clinical stage I and stage II cases, the 5 year survival rate of positive node and negative node was 38.9% and 74.2% respectively, with significant difference (P < 0.005). No significant difference was found between cases with pelvic lymphadenectomy and those without pelvic lymphadenectomy (P > 0.05) in pathologic stage I and stage II cases. CONCLUSIONS: Positive pelvic node is an important prognostic factor in endometrial carcinoma. Pelvic lymphadenectomy can not improve prognosis in early stage patients with endometrial carcinoma. It is not necessary to perform pelvic lymphadenectomy for stage I case, because of low incidence of positive node.

Adult↗

PubMed2000

Vitamin D receptor gene polymorphism in postmenopausal women of the Han and Uygur nationalities in China.

OBJECTIVE: Polymorphism in vitamin D receptor (VDR) gene has been reported to play a major role in variations for genetic regulation of bone mass. Its role within various ethnic populations is not clear. The purpose of this study was to determine the frequencies of VDR genotypes in the Han and Uygur nationalities in China. METHODS: We analyzed the polymorphism of Bsm I restriction enzyme by PCR-RFLP technique in 162 healthy postmenopausal women of the Han nationality and 50 healthy postmenopausal women of the Uygur nationality in China. The genotype frequencies of VDR were calculated using Hardy-Weinberg equilibrium formula. RESULTS: In the Han nationality, the bb, Bb, and BB genotype accounted for 91.36%, 8.64% and 0%, respectively. In the Uygur nationality, frequencies were 74.00%, 18.00% and 8.00%, respectively. CONCLUSION: There was a significant difference between the Han and Uygur nationalities in the frequency distribution of VDR genotype (P < 0.01). Compared with the Caucasian population in the United States, Australia and France, there was a similar value to Uygur nationality in the BB genotype. This investigation gave us further evidence on the different etiopathology of osteoporosis in various ethnic groups.

Alleles↗

PubMed2000

[Clinical study on effect of Tripterygium wilfordii Hook. f. on uterin leiomyoma].

OBJECTIVE: To observe the therapeutic effect of Tripterygium wilfordii Hook. f. on patients with uterine leiomyoma. METHODS: Baseline ultrasound examinations of myomas and uterine were obtained and repeated three months, six months after treatment. Blood samples were collected in the mid-follicular or mid-luteal phase of the menstrual cycle before initiation of Tripterygium wilfordii Hook. f. therapy and after treatment 3-4 months and 5-6 months, for determination of estradiol, progesteron, testosterone, follicle-stimulating hormone, luteinizing hormone and prolactin by radioimmunoassay. RESULTS: Significant decrease in leiomyoma volume was detected in 39 of 65 (60.0%) patients after 3-4 months of Tripterygium wilfordii Hook. f. treatment and 28 of 40 (70.0%) patients after 5-6 months of treatment. The decrease in leiomyoma volume with Tripterygium wilfordii Hook. f. treatment was time-dependent while 27.84% in 3-4 months, 51.6% in 5-6 months. 25 of 65 patients were amenorrheic during the course of treatment. Compared with pretreatment values, Tripterygium wilfordii Hook. f. treatment induced an increase in mean luteinizing hormone, fdlicle-stimulating hormone levels and a decrease in mean estradiol, progesterone levels. CONCLUSIONS: Tripterygium wilfordii Hook. f. may be an effective therapeutic agent for leiomyomas with fewer side effects. Tripterygium wilfordii Hook. f. treatment showed a reversibly inhibitory effect on the ovary. It may be one of the mechanisms of Tripterygium wilfordii Hook. f. in decreasing leiomyoma volume.

Estradiol↗

PubMed2000

[Purification of hsp70 and its immunoprotective effect against mouse hepatoma].

OBJECTIVE: To purify hsp70 protein and observe its anti-tumor effect on mouse H22 hepatoma. METHODS: Cytosolic hsp70 protein of heat treated H22 cells was purified successively by chromatographic procedures, including DEAE 52-cellulose, ConA-sepharose 4B and ADP-argarose chromatography. The molecular weight and the identity of the purified hsp70 protein were confirmed by SDS-PAGE and Western blot. Tumorigenicity of H22 hepatoma was examined in purified hsp70-treated C3H mice. RESULTS: A sharp stained protein band with a molecular weight of about 70 kD was obtained and shown to be hsp70 as confirmed by Western blot. In C3H mice challenged with H22 hepatoma, tumor developed in 6 of 6 mice while in hsp70 pretreated mice, none of the 6 H22 challenged mice developed tumor. Nevertheless, C57BL/6 mice pretreated with hsp70 or RPMI 1640 all developed tumor upon challenge with EL-4 lymphoma. CONCLUSION: The results suggest that the immunoprotective effect of hsp70 protein is due not to hsp70 per se, but rather to the specific antigenic peptides it carries.

Animals↗

PubMed2000

[Thrombosis diseases and lung cancer].

OBJECTIVE: To increase the awareness of lung cancer complicating thrombosis disease(TD). METHODS: 20 cases of lung cancer with TD which were from 1,050 cases of lung cancer confirmed by pathology and cytology in 80's and 90's from a teaching hospital were retrospectively reviewed. RESULTS: Of the 20 cases, there were 8 cases complicated with deep venous thrombosis(DVT); 4 cases with pulmonary thromboembolism (PTE); 4 cases with DVT and PTE, and 4 cases with nonbacterial thrombotic endocarditis (NBTE). 6 cases of DVT/PTE occurred 2-6 months before detection of lung cancer, 3 cases of NBTE had brain and peripheral artery embolism 2-7 months before detection of lung cancer. The pathology of 12 cases of lung cancer with TD was adenocarcinoma. CONCLUSIONS: TD complicating lung cancer was not unusual and could be warning sign indicating occult lung cancer. Physician ought to alert to lung cancer or other cancers when facing aged healthy subjects of sudden TD under unknown origin. The most common physiologic type of lung cancer complicating TD was adenocarcinoma. Hypercoagulation state was the most important cause of TD complicating lung cancer.

Adult↗

PubMed2000

[The expression of cathepsin-D in salivary adenoid cystic carcinoma].

OBJECTIVE: To investigate the relationship between Cathepsin-D(Cath-D) and the prognosis of patients with salivary adenoid cystic carcinoma (SACC). METHODS: The immunoactivity of Cath-D of 52 cases with SACC was determined by immunohistochemistry method (Streptavidin-Biotin method). The relationship between Cath-D and the histological type, clinical stage, local recurrence, distant metastasis of the tumor and survival rate of the patients with SACC were analysed. RESULTS: Statistical analysis showed that the expression levels of Cath-D were correlated positively with distant metastasis potential and clinical stage (P < 0.05), and had no significant relation with histological type, local recurrence and survival rate (P > 0.05). CONCLUSIONS: Cath-D can facilitate invasiveness and distant metastasis of SACC; evaluation of Cath-D can act as a predictor of distant metastasis of SACC and direct the clinical treatment.

Adult↗

PubMed2000

[Clinical pathological analysis of clear cell odontogenic carcinoma].

OBJECTIVE: To investigate clinical pathological characteristics and biologic behavior of clear cell odontogenic carcinoma. METHODS: Analysis of clinical data, microscopic and electromicroscopic observation of 8 cases of clear cell odontogenic carcinoma. RESULTS: The tumor occurred mainly in female and involved right mandible. 37.5% had regional lymph node metastases at the time of operation. Recurrence rate was 33.3%. The tumor had no capsule and consisted of clear cell and basaloid cells which arranged in nests and strands. Tumor cells often grew close to the blood vessels and caused bone resorption. There were less cell organelle and swelling of mitochondria. CONCLUSION: This tumor belongs to middle grade malignant tumor and should be called clear cell odontogenic carcinoma.

Adenocarcinoma, Clear Cell↗

PubMed2000

[The protein expression of insulin receptor substrate-1 and protein tyrosine phosphatase with two src-homology II in the adipose tissue from type II diabetic patients].

OBJECTIVE: To investigate the protein expression of insulin receptor substrate-1 (IRS-1), protein tyrosine phosphatase with two src-homology 2 (SH-PTP(2)) in adipose tissues of type II diabetic patients, and explore molecular mechanisms of insulin resistance from adipose tissues of type II diabetic individuals. METHODS: The levels of protein expression of IRS-1 and SH-PTP(2) in adipose tissues from type II diabetic individuals were measured by Western blot analysis; meanwhile compared the level of protein expression of one's own abdominal subcutaneous and omentum majus adipose tissue from patients with type II diabetes mellitus. RESULTS: The expression of IRS-1 protein in abdominal subcutaneous (A) 2.14 +/- 0.67 and omentum majus 3.25 +/- 0.70 adipose tissues from patients with type II diabetes mellitus was significantly lower than that of control group [subcutaneous: 4.33 +/- 0.57 (P < 0.001), omentum majus: 8.65 +/- 2.85 (P < 0.05)]. The expression of SH-PTP(2) protein had no difference compared with control group (P > 0.05). The protein expression of IRS-1 was significantly lower in abdominal subcutaneous adipose tissue (1.09 +/- 0.13) than that in omentum majus adipose tissue (2.10 +/- 0.22) from the type II diabetic patients (P < 0.05), but the protein expression of SH-PTP(2) was significantly higher in subcutaneous adipose tissue (70.75 +/- 2.18) than that in omentum majus (43.69 +/- 11.07, P < 0.05). CONCLUSION: The abnormal changes in expression of IRS-1 and SH-PTP(2) protein in adipose tissues of the patients with type II diabetic mellitus may be one of the mechanisms of leading to insulin resistance. The abdominal subcutaneous adipose tissue of type II diabetic patients, as visceral adipose tissues, contributes to their insulin resistance.

Adipose Tissue↗