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Biomedical subjects

B Xu

Publications and source records attributed to B Xu.

At least 235 records · Page 13Linked to original sources
PubMed1997

alpha-Anordrin-induced apoptosis of leukemia K562 cells is not prevented by cicloheximide.

AIM: To study effect of protein synthesis inhibitor cicloheximide (Cic) on the apoptosis induced by alpha-anordrin (Ano) in leukemia K562 cells. METHODS: Morphological changes were observed by fluorescent microscopy. DNA content was measured by flow cytometry. DNA fragmentation was analyzed by agarose gel electrophoresis. RESULTS: Exposure of K562 cells to Ano 50 mumol.L-1 for 24 h induced apoptotic cell death. Cic 1 mumol.L-1 did not abrogate or delay this effect. Indeed, Ano-induced apoptosis was augmented by Cic. Cic 100 mumol.L-1 itself stimulated 25% K562 cell apoptosis after 24-h culture. CONCLUSION: Ano-induced apoptosis was independent of de novo protein synthesis.

Antineoplastic Agents↗
PubMed1997

[Antitumor and immunological activities of oxalysine].

OBJECTIVE: To study the antitumor and immunological activities of oxalysine (OXL). METHODS: Growth of mouse ascites hepatoma-22 (H-22) cells and splenocyte proliferation were investigated in vitro by MTT colorimetric assay. RESULTS: Suppression of OXL (6.3-200 micrograms/ml) on H-22 cell growth was weaker when used singly. But a marked synergetic inhibition was observed when OXL was used in combination with 5-fluorouracil (5-Fu), with suppression percentage on hepatoma growth increased to 43.1% from 13.8% (25 micrograms/ml of OXL alone) or 18.9% (3.1 micrograms/ml of 5-Fu alone). OXL (6.3-100 micrograms/ml) in vitro produced an inhibitory action on splenocyte proliferation induced by concanvilian A (Con A, 5 micrograms/ml) in the normal mice, but was able to enhance obviously the proliferative response in mice bearing H-22. CONCLUSION: OXL inhibits H-22 cell growth. The immunoregulatory action of OXL may contribute to its antihepatoma activity.

Adjuvants, Immunologic↗
PubMed1997

[Phase III clinical studies with ondansetron (Qilu) in the prophylaxis of nausea and vomiting induced by non-cisplatin chemotherapy].

OBJECTIVE: This study was undertaken to further determine the clinical value of ondansetron (OND, supplied by Qilu Pharmaceutical Company) in the prophylaxis of nausea and vomiting induced by non-cisplatin chemotherapy. METHODS: A total of 193 patients were enrolled in the multicenter prospective study and were given treatment of non-cisplatin based chemotherapy. All patients were treated with OND 8 mg i.v. once a day during chemotherapy, followed by OND 4 mg orally twice a day for one day after chemotherapy. RESULTS: The effective control rate (0-2 emetic episodes) on the first day was 93.3%. Total control of delayed vomiting (day 2-5) was as high as 94.8 to 99.5%. The mean frequency of vomiting was 0.4, 0.4, 0.2, 0.1 and 0.1, respectively from day 1 to day 5. Adverse effects were minor and tolerable. CONCLUSION: This modified regimen of treatment with OND is effective in the control of vomiting induced by non-DDP chemotherapy.

Adolescent↗
PubMed1997

[Phase III clinical studies with ondansetron (Qilu) in the prophylaxis of nausea and vomiting induced by cisplatin].

OBJECTIVE: To further evaluate the clinical usefulness of ondensetron(OND, supplied by Qilu Pharmaceutical Company) with modified regime in the prevention of cisplatin (DDP)-induced nausea and vomiting. METHODS: A total of 773 patients were enrolled in a multicenter cooperative study. Of them, 330 patients were given i.v. OND 8 mg once or twice a day and 443 patients were given i.v. OND 8 mg plus dexamethasone(DXM) 10 mg once a day during the therapeutic period of DDP, followed by OND 4 mg orally twice a day for two days after DDP treatment. RESULTS: Effective control of acute nausea was achieved in 86.7% and 94.8% of the patients receiving OND alone and OND plus DXM, respectively(P < 0.001). The mean frequency of vomiting was 0.9 times in OND and 0.4 times in OND plus DXM(P < 0.01). Total control of delayed vomiting (day 2-5) was comparable in both groups. Complete inhibition of vomiting (CR rate) was more frequently observed in males than in females. Adverse effects were identical and well tolerated. CONCLUSION: OND with modified regimen is effective in the control of DDP-induced vomiting. It is more effective when OND and DXM are given than OND given alone.

Adolescent↗
PubMed1997

[The clinical course and treatment results of lung metastases from breast cancer].

OBJECTIVE: To analyse the clinical course and treatment result of lung metastases from breast cancer. METHODS: 122 cases with lung metastases from breast cancer were treated by chemotherapy or chemotherapy plus endocrine therapy. Treatment results were assessed according to WHO criteria and survival rate estimated using the life table. RESULTS: The median time from initial treatment of primary tumour to lung metastases was 22 months. Sites of common consecutive metastases were lung, liver and bone. The overall response rate was 48% with a CR rate of 15%. Compared to non-DDP-encompassing regimen, the CR rate was higher in DDP-based chemotherapy (7% versus 21%, P < 0.05) with a longer median survival time (MST). The PR rate was higher in regimen containing anthracycline (48%) than in that without anthracycline (20%, P < 0.01). The response rate was similar between chemotherapy and chemotherapy plus endocrine therapy (P > 0.05). No difference in MST was observed between patients receiving anthracycline- and non-anthracycline-encompassing regimens. The 1-,3-,5- and 10-year survival rate was 77%, 22%, 11% and 10%, respectively. The size of primary tumour, the length of disease-free interval, the number of lung metastases may provide additional information for predicting patients' survival after treatment of lung metastases. CONCLUSION: Combination chemotherapy, especially DDP-based chemotherapy may prolong survival time of patients with lung metastases from breast cancer.

Adult↗
PubMed1997

[The detection of serum hepatitis B virus Pre-S1 antigen and its relationship with HBeAg/anti-HBe and HBV DNA by polymerase chain reaction].

150 specimens were collected from chronic hepatitis patients, asymptomatic hepatitis B surface antigen (HBsAg) carriers and healthy individuals. Serum Pre-S1 and HBV markers were determined by enzyme immunoassay (EIA) and HBV DNA was tested by polymerase chain reaction (PCR). According to the results, specimens could be classified into five different groups: HBsAg and hepatitis e antigen (HBeAg) both positive; HBsAg positive and HBeAg/anti-HBe both negative; HBsAg and anti-HBe both positive with HBeAg negative; HBsAg negative with positive antibodies to s, c and e antigens; negative in all HBV markers. Each groups comprised 30 specimens respectively. The positive rate and relative titer (sample A value/cut-off value) of Pre-S1 Ag in HBeAg positive group (66.6%, 4.3250 +/- 2.2013, respectively) were markedly higher than those in HBeAg negative group (31.6%, 1.7863 +/- 0.6339, respectively, P<0.01). The detection rate of Pre-S1 Ag in these samples were 82% coincided with that of HBV DNA. The positive rate of Pre-S1 in the sera from five groups with different HB markers were well correlated to that of HBV DNA (r=0.9826, P<0.01). These results suggest that serum Pre-S1 detection can be used as a marker for the presence of the HBV genome and its quantitation will be correlated with the replication of virus.

DNA, Viral↗
PubMed1997

Immunoregulatory activities of L-4-oxalysine: an in vitro study.

The present study was undertaken by in vitro experiments to determine the effect of L-4-oxalysine (OXL), a new natural product in China, on immunological responses. The immunological parameters evaluated were one-way mixed lymphocyte reaction and interleukin-6 activity stimulated by lipopolysaccharide. The results showed that the immunological functions of spleen cells from normal mice were significantly suppressed by in vitro treatment of OXL. However, OXL markedly enhanced the immunological responses of spleen cells from mice bearing hepatoma-22 tumor. It was indicated that OXL exerted obvious immunoregulatory activities.

Adjuvants, Immunologic↗
PubMed1997

Studies on the transmission potential of surviving microfilaremias after basic control of filariasis.

After filariasis was basically controlled (the microfilarial rate was lower than 1%) in Henan Province in 1987, longitudinal observation of the disease has been carried out in all the province in order to study the regular pattern of growth and decline or the transmission potential of the disease. According to the distribution of filaria species and original microfilarial rate, 7 administrative villages in 7 counties were selected as surveillance sites. From 1988 to 1995, etiological and mosquito vector surveys were made continuously in all sites where no control measure was conducted. 10 surviving microfilaremic individuals became negative gradually over the first 6 years and no new microfilaremia was found. Since then, the microfilarial rate was zero. During the 8 years, 19 vector mosquitos were positive, with a total of 33 filarial larva. Culex pipiens pallens was the predominant mosquito species inside human dwelling in all sites. The man-biting rate of mosquitos for outdoor sleepers fluctuated greatly, the highest was 360.60 mosquitos per man per night and the lowest 7.20. The man-biting rate of mosquitos for sleepers inside mosquito-nets was approximately 1. The proportion of multiparous mosquitos also fluctuated greatly, the highest was 88.10% and the lowest 27.27%. According to the data described above, the man-biting rate of mosquitos which contained filaria L3 was less than 1 mosquito per man per transmission season. It is suggested that after the microfilarial rate was lower than 1%, the surviving microfilaremias became negative gradually in 3-5 years, and the transmission of the disease was blocked. Therefore, in the districts where filariasis was basically controlled, elimination of the disease was attainable.

Animals↗
PubMed1997

Multiprimer--PCR for screening of IgH and T-cell receptor rearranged genes in acute lymphoblastic leukemia.

OBJECTIVE: To develop a multiprimer-polymerase chain reaction (multiprimer-PCR) method for detecting immunoglobulin heavy chain (IgH) and T-cell receptor (TCR) rearranged genes in the same amplification. METHODS: Multiprimer-PCR protocol, a mixture of four different primers used in the same reaction detected IgH CDR-III and TCR V gamma I-J gamma Ligenetic rearrangements in 40 acute lymphoblastic leukemia (ALL) patients. RESULTS: Thirteen cases were found to have IgH CDR-III and TCR V gamma I-J gamma genetic rearrangements. Ten cases were found to have TCR V gamma I-J gamma genetic rearrangements. Thirteen cases were found to have IgH CDR-III genetic rearrangements. The amplification result of multiprimer-PCR was the same as separate amplification. The sensitivity of multiprimer-PCR was 10(-4)-10(-5) DNA level, which was the same as separate PCR amplification. All positive cases with IgH rearranged gene were confirmed by Southern blot. CONCLUSION: Multiprimer-PCR could screen two distinct rearranged genes in a single amplification, and is more suitable for screening of specimens collected at diagnosis.

Adolescent↗
PubMed1997

Studies on the transmission potential of filariasis in controlled areas of Henan Province.

OBJECTIVE: To study the regular pattern of growth and declination or the transmission potential of filariasis after the disease was basically (the microfilarial rate was lower than 1%) in Henan Province in 1987. METHODS: According to the distribution of filaria species and original microfilarial rate, in 7 surveillance sites in 7 counties (cities) the etiology and mosquito vector surveys were carried out continuously during 1988-1995 and no control measurement for pathogen was taken. RESULTS: Ten residual microfilaremias became negative gradually in the first 6 years and no new microfilaremias occurred during 1988-1995. During 1993 to 1995, the microfilaremias rate of population in the sites was 0. The natural infection rates of filarial larvae in vector mosquito were 0.1%-0. During the 8 years, 15 vector mosquitos were positive with a total of 18 filarial larvae which were all of first or second-stage larvae. The C. pipiens pallens was the main vector, the second was A. sinensis, with a small number of C. fatigans and A. anthropophagus. The man-biting rates of mosquitoes for outdoor sleepers fluctuated greatly, the highest one was 360.6 mosquitoes/person per night and the lowest, 7.2. The man-biting rates of mosquitoes for sleepers inside mosquito-net was about 1 mosquito/person per night. The proportion of multiparous mosquitoes also fluctuated more greatly, the highest one was 88.1% and the lowest 27. 2% According to the data described above, the man-biting rate of vector mosquito which contained filarial L3 was 0. CONCLUSIONS: The results suggested that after the microfilarial rate was lower than 1%, the residual microfilaremias became negative gradually in 3-6 years, and the transmission of the disease was blocked. Therefore, in the areas where filariasis was basically controlled, elimination of the disease was attainable within sight.

Animals↗
PubMed1997

[Effect of microinjection of CRH into rat central nucleus of amygdala on blood pressure and its central mechanism].

The effect of microinjection of corticotropin releasing hormone (CRH) into the central nucleus of amygdala (CeA) on blood pressure was examined in Wistar rats anaesthetized with pentobarbital sodium. The results were as follows: (1) Microinjection of CRH 100, 500 ng into the CeA produced a dose-dependent increase in blood pressure. The response occurred 5 min after injection and lasted for at least 1 h. (2) The response could be blocked by injection of CRH receptor antagonist alpha-helical CRH9-41 into CeA. (3) Lateral ventricle injection of naloxone could also attenuate the pressor response of CRH. (4) After injection of alpha-helical CRH9-41 into nucleus of solitary tract, the pressor response of CRH was diminished. The results suggest that the pressor effect induced by microinjection of CRH into the CeA might be partly mediated through opioid system via a descending pathway from CeA to NTS.

Amygdala↗
PubMed1996

Adenovirus-mediated interleukin-12 gene therapy for metastatic colon carcinoma.

Recombinant adenoviral mediated delivery of suicide and cytokine genes has been investigated as a treatment for hepatic metastases of colon carcinoma in mice. Liver tumors were established by intrahepatic implantation of a poorly immunogenic colon carcinoma cell line (MCA-26), which is syngeneic in BALB/c mice. Intratumoral transfer of the herpes simplex virus type 1 thymidine kinase (HSV-tk) and the murine interleukin (mIL)-2 genes resulted in substantial hepatic tumor regression, induced an effective systemic antitumoral immunity in the host and prolonged the median survival time of the treated animals from 22 to 35 days. The antitumoral immunity declined gradually, which led to tumor recurrence over time. A recombinant adenovirus expressing the mIL-12 gene was constructed and tested in the MCA-26 tumor model. Intratumoral administration of this cytokine vector alone increased significantly survival time of the animals with 25% of the treated animals still living over 70 days. These data indicate that local expression of IL-12 may also be an attractive treatment strategy for metastatic colon carcinoma.

Adenoviridae↗
PubMed1996

Combination suicide and cytokine gene therapy for hepatic metastases of colon carcinoma: sustained antitumor immunity prolongs animal survival.

The effectiveness of combination therapy using a suicide gene and cytokine genes for the treatment of metastatic colon carcinoma in the mouse liver was investigated. Pre-established hepatic tumors treated with a recombinant adenoviral vector containing the herpes simplex virus thymidine kinase gene(tk) exhibited substantial regression, although all treated animals suffered from subsequent relapses. Although cotreatment with a mouse interleukin 2 (mIL-2)-containing adenoviral vector induced an effective antitumor immune response, the immunity waned with time, and the treated animals eventually succumbed to hepatic tumor relapse or distant metastases. In this study, mouse granulocyte macrophage colony-stimulating factor (mGM-CSF) gene was tested for its ability to further enhance and prolong the antitumoral cellular immunity. A fraction of the animals treated with tk + mIL-2 + mGM-CSF developed long-term antitumor immunity and survived for more than 4 months without recurrence. This long-term antitumor immunity could be enhanced further by subsequent "vaccination" with mIL-2-expressing parental tumor cells. The results indicate that local expression of GM-CSF in the hepatic tumors and prolonged mIL-2 expression are necessary to generate persistent antitumor immunity that is essential for the prevention of tumor recurrence and long-term animal survival.

Animals↗
PubMed1996

RNA-DNA hybrid formation at the human mitochondrial heavy-strand origin ceases at replication start sites: an implication for RNA-DNA hybrids serving as primers.

Critical elements of a mammalian mitochondrial DNA heavy-strand replication origin include a promoter and three downstream conserved sequence blocks (CSBIII, CSBII and CSBI). We found recently that a stable and persistent RNA-DNA hybrid forms during in vitro transcription at Saccharomyces cerevisiae mitochondrial origins; hybrid formation was dependent on the conserved CSBII element. We report here that during in vitro transcription with human mitochondrial RNA polymerase, stable and persistent RNA-DNA hybrid formation is also evident at the human mitochondrial heavy-strand origin. As predicted, hybrid formation was dependent on the GC-rich CSBII element. The human RNA-DNA hybrids terminate within or downstream of CSBI at locations implicated in initiation of mitochondrial DNA replication. Interestingly, efficient hybrid formation in the human system is influenced by sequence 5' to the RNA-DNA hybrid, including the CSBIII element. These results suggest that the RNA-DNA hybrids formed during transcription across the mitochondrial DNA heavy-strand origin provide RNA primers for initiation of mitochondrial DNA replication.

Base Sequence↗
PubMed1996

Src homology domains of v-Src stabilize an active conformation of the tyrosine kinase catalytic domain.

To examine the interactions between Src homology domains and the tyrosine kinase catalytic domain of v-Src, various combinations of domains have been expressed in bacteria as fusion proteins. Constructs containing the isolated catalytic domain, SH2 + catalytic domain, and SH3 + SH2 + catalytic domains were active in autophosphorylation assays. For the catalytic domain of v-Src, but not for v-Abl, addition of exogenous Src SH3-SH2 domains stimulated the autophosphorylation activity. In contrast to results for autophosphorylation, constructs containing Src homology domains were more active towards a synthetic peptide substrate than the isolated catalytic domain. The ability of the SH2 and SH3 domains of v-Src to stabilize an active enzyme conformation was also confirmed by refolding after denaturation in guanidinium hydrochloride. Collectively the data suggest that, in addition to their roles in intermolecular protein-protein interactions, the Src homology regions of v-Src exert a positive influence on tyrosine kinase function, potentially by maintaining an active conformation of the catalytic domain.

Adenosine Triphosphate↗
PubMed1996

T cells bound by vascular cell adhesion molecule-1/CD106 in synovial fluid in rheumatoid arthritis: inhibitory role of soluble vascular cell adhesion molecule-1 in T cell activation.

Elevated levels of soluble vascular cell adhesion molecule-1 (sVCAM-1)/CD106 have been reported in synovial fluid (SF) from patients with rheumatoid arthritis (RA). In the present study, VCAM-1-positive lymphocytes were found in SF from RA patients. The data strongly suggest that sVCAM-1 might be bound to lymphocytes in SF. rsVCAM-1 in the fluid phase can bind to both SF lymphocytes and IL-2-dependent T cell lines with up-regulated expression and binding activity of VLA-4. Furthermore, proliferative responses of SF mononuclear cells (SFMC) with PHA, immobilized anti-CD3, or anti-CD2 and PMA were inhibited to various extents in the presence of rsVCAM-1, but only PMA-induced proliferative response of PBMC from normal individuals was inhibited notably in the presence of rsVCAM-1. rsVCAM-1 also drastically reduced IL-2 production of Jurkat leukemic T cells possessing high affinity VLA-4 with the stimulation of anti-CD3 and PMA, suggesting that the T cell hyporesponsiveness induced by rsVCAM-1 might stem from impairment of IL-2 production. These results indicate that sVCAM-1 provides a negative signal to T cell activation, probably by affecting the pathway of protein kinase C activation. Thus, binding of sVCAM-1 to SF lymphocytes might partly explain the anergic state of these lymphocytes.

Arthritis, Rheumatoid↗