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Biomedical subjects

B Xu

Publications and source records attributed to B Xu.

At least 361 records · Page 20Linked to original sources
PubMed1990

[A new therapy of hemophilia with ranitidine].

20 cases of hemophilia, including ten of hemophilia A , nine of hemophilia B and one of von Willebrand's disease (VWD), were treated with ranitidine. The results revealed that the levels of both factor VIII and IX were increased and the clinical symptoms of bleeding were ameliorated. The level of factor VIII in hemophilia A ranged from 5.27 +/- 3.94% before treatment and rose to 14.68 +/- 4.70% during the treatment period (P less than 0.001). The level of the factor IX in the patients with hemophilia B increased from 4.42 +/- 3.01% before treatment to 20.33 + 9.31% under treatment (P less than 0.001). Tn the patient with VWD the level of the factor VIII rose but the level of von Willebrand factor did not change. The drug has no side effect. The results of our study suggests that ranitidine therapy is effective and safe in hemophilia.

Adolescent↗
PubMed1990

[Demonstration of the presence of Methanobrevibacter in a colon cancer Chinese patient].

A fecal specimen from a Chinese patient (85-year-old man) suffering from colonic cancer was examined for the presence of methane-producing bacteria. As a result, a Methanobrevibacter organism was isolated. Our isolate did not grow in the presence of bile salts, a result different from Methanobrevibacter from healthy Americans' feces by Miller et al.

Aged↗
PubMed1990

Effects of lycobetaine on chromatin structure and activity of murine hepatoma cells.

The effects of lycobetaine (LBT) on DNA single strand break and chromatin conformation were examined by in-situ nick translation method. It was found that LBT did not cause DNA single strand break. After 2-h incubation of murine hepatoma cells with 1-50 micrograms/ml LBT in vitro, the chromatin transcription activity was inhibited gradually. This effect was time- and dose-dependent. Actinomycin D produced a similar effect; 10-hydroxycamptothecin not only caused DNA single strand break, but also altered chromatin conformation; homoharringtonine had no marked influence on either. By molecular hybridization technique, it was found that the effect of LBT on individual genes was somewhat different. After 2-h incubation of the cells with LBT, the sensitivities of c-myc, N-ras, and beta 2-microglobulin genes to DNase I were decreased from 75 +/- 6, 66 +/- 4, 70 +/- 8% to 28 +/- 8, 25 +/- 5, 28 +/- 7%, respectively, while that of c-myb and beta-globin genes (8 + 6%, 6 + 5%) did not change obviously.

Alkaloids↗
PubMed1989

Biological response modifier enhances the activity of natural killer cell against human cytomegalovirus-infected cells.

Peripheral blood lymphocytes (PBL) from two human cytomegalovirus (CMV)-seronegative donors and eight CMV-seropositive donors were cultured for 3 days with or without the biological response modifier OK-432 and examined for lysis of K562 cells and CMV-infected MRC-5 cells. OK-432-stimulated PBL exhibited significantly greater natural killer (NK) activity than did unstimulated PBL. There was no difference in activity of NK cells in PBL prepared from CMV-seronegative and -seropositive donors. Antibody-complement depletion studies suggested that OK-432-stimulated NK activity was associated with Leu-7-positive cells. The ability of OK-432 to sustain the NK activity in PBL was decreased when the CD4-positive population of lymphocytes was eliminated by antibody-complement depletion prior to OK-432 stimulation. The ability of OK-432 to sustain the NK activity of PBL was also significantly decreased in the presence of monoclonal antibody against recombinant human interleukin-2. The results suggest that the activity of human NK cells against K562 and CMV-infected MRC-5 target cells can be sustained in vitro by OK-432-stimulated T-helper cells and that the effect of the T-helper cells is mediated, at least in part, by interleukin-2.

Adult↗
PubMed1989

[Influence of zinc deprivation on thymus, spleen development and adenosine deaminase activity in young rats].

This study on the thymus and spleen development and ADA activity was done in young rats with zinc deprivation and supplementation. The serum zinc level, body weight, absolute and relative weight, and ADA activity of the thymus and spleen were compared between the experimental rats and the control group. Above indications were all decreased; especially both the thymus weight and the thymus ADA activity were markedly decreased in the zinc deficient group. The averages of thymic absolute weight, relative weight and ADA activity were dropped by 61.32%, 54.54% and 47.59%, respectively. After zinc supplementation for one month, all the body weight, weight of the thymus and spleen, and ADA activity of the spleen were recovered to the control group's level, while ADA activity of the thymus was 33.03% higher than that of the control group. Our data suggested that zinc was not only an important trace element in maintaining the growth of the body, the development of the thymus and spleen, but it may be an important agent to activate the ADA or to prompt synthesis of ADA.

Adenosine Deaminase↗
PubMed1989

Characteristics of the interaction of lycobetaine with DNA.

The characteristics of the interaction of lycobetaine (LBT) with DNA were examined by fluorescence spectrometer, disc electrophoresis and restriction enzyme analysis. The apparent binding constant of LBT with calf thymus DNA has been determined as 1.67 x 10(6) L/mol by ethidium bromide displacement method. Based on electrophoresis titration, the mode of DNA binding was found to be through intercalation. Fluorescence quenching assay showed that the intrinsic association constant and the binding site size of LBT to calf thymus DNA were 0.26 x 10(6) L/mol and 2.6 base pairs, respectively. Selective inhibition of LBT on action of some restriction enzymes showed that LBT intercalate preferentially into GC base pairs. Neither DNA strand break nor interstrand cross-link was produced by LBT. LBT did not bind to DNA covalently and did not cause DNA alkylation.

Alkaloids↗
PubMed1987

Nephrotoxicity and hepatotoxicity of 1,1-dichloro-2,2-difluoroethylene in the rat. Indications for differential mechanisms of bioactivation.

1,1-Dichloro-2,2-difluoroethylene (DCDFE) produced marked nephrotoxicity in rats upon an i.p. dose of 150 mumole/kg. At doses higher than 375 mumole/kg, DCDFE also produced hepatotoxicity. Aminooxyacetic acid, an inhibitor of cysteine conjugate beta-lyase, appeared to be slightly nephrotoxic in Wistar rats. Nevertheless it exerted an inhibitory effect on the nephrotoxicity of DCDFE. The N-acetylcysteine conjugate of DCDFE was identified as a major urinary metabolite of DCDFE. When administered as such, this conjugate appeared to be a potent nephrotoxin, without any effect on the liver, indicating that glutathione conjugation of DCDFE is most likely a bioactivation step for nephrotoxicity. The appearance of traces of chlorodifluoroacetic acid in urine of rats treated with higher doses of DCDFE indicates the existence of an oxidative pathway of metabolism of DCDFE, probably involving epoxidation by hepatic mixed-function oxidases. It is speculated that the latter route might account for the hepatotoxicity at higher doses of DCDFE. The nephro- and hepatotoxicity of DCDFE, therefore, most likely are the result of two different mechanisms of bioactivation.

Acetates↗
PubMed1987

[Transplantation model of human lung oat cell carcinoma in nude mice].

A human lung oat cell carcinoma from a surgical specimen was successfully transplanted into nude mice and has been maintained for over four years through 14 passages. This transplanted tumor had a long latent period of more than one month, slowly growing in the initial inoculation and the following passages. The interval between two passages was about four months. 5 months after the inoculation, the transplanted tumor in nude mice grew to 2 cm in diameter. It was demonstrated that the transplanted tumor possessed the human isoenzyme pattern and human chromosome karyotype. The original human tumor and its transplanted counterparts in the nude mice were strikingly similar by histopathology. Besides, specific neuro-secretory granules in cytoplasm of the transplanted tumor were observed under transmission electron microscope.

Aged↗
PubMed1987

[Ultrastructural study on the model of human lung adenocarcinoma heterotransplanted to nude mice].

A human lung adenocarcinoma from surgical biopsy specimen was successfully heterotransplanted into nude mice and has been maintained for 40 generations. The experiments were made on 6-8 week old male or female nude mice with Swiss genetic background cultivated in specific pathogen-free condition. The electron microscopic observation on transplanted tumor of passages 2, 6, 12, 18 and 23 revealed that the ultrastructural features of this tumor were strictly maintained and no obvious change of differentiation was found. But there was a potential prone to regional squamous epithelial metaplasia in the transplanted tumor. The nude mice model of human lung adenocarcinoma so established can be used as a good experimental system of the homologous and reproducible human cancer for the study of basic medical sciences and chemotherapy of human lung carcinoma.

Adenocarcinoma↗
PubMed1986

[Changes in protein in bile excretion from rat liver inoculated with BERH-2 hepatoma].

Rocket immunoelectrophoresis was used to assay the change in alpha fetoprotein (AFP) and albumin (Alb) in bile of rats 10 to 14 days after intrahepatic or intraperitoneal inoculation of BERH-2 hepatoma. The bile was collected from the common bile duct cannula. Total protein was determined by the Lowry method. The results showed that the excretion of total protein and Alb was reduced to 54% and 24% of the control in the intrahepatic group, and 65% and 56% of the control in the intraperitoneal group. Bile-AFP can be detected in rats in both groups and its concentration increased gradually during the tumor progression. In the hepatic group, the bile-AFP content per gram of tumor tissue was 29% of that in the intraperitoneal group. It suggests that decreased excretion of AFP, Alb and total protein in bile of rat bearing tumor in the liver be related to local obstruction of excretion by the tumor mass leading to constriction of biliary canaliculi.

Albumins↗