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Biomedical subjects

B Wang

Publications and source records attributed to B Wang.

At least 847 records · Page 47Linked to original sources
PubMed1992

[Plasmid analysis and antibiotic resistance pattern measurement of Shigella in Chengdu].

A total of 81 strains of Shigella isolated from sporadic cases and cases in an outbreak of Shigella sonnei infection was analysed by plasmid profiles and antibiotic resistance patterns. The strains had a high resistance patterns. The strains had a high resistance of ampicillin, tetracycline, trimethoprim-sulfamethoxazole and chloramphenicol; while 97.2% of the strains were susceptible to gentamicin, kanamycin. The results showed that 50% of the strains harbored plasmid patterns within each species, which indicated that many genetically different strains of Shigella were responsible for dysentery epidemics in Chengdu. According to the results of the plasmid analysis and antibiotic resistance pattern measurement made in the outbreak strains, it was clearly seen that most of the strains were similar or fundamentally similar, which suggested that one or two strains with genetical homology were the main causative agent for the outbreak. We think that plasmid profiles and antibiotic resistance patterns are applicable to the identification of the outbreak strains of dysentery as an efficient epidemiologic tool.

Ampicillin Resistance↗
PubMed1992

[Inhibitory effects of the extract of pilose antler on monoamine oxidase in aged mice].

It was demonstrated that the water extract of Pilose Antler (WEPA) showed a higher inhibitory effect on MAO-B activities in the liver and brain tissues of aged mice, but nearly no effect on NAO-A. WEPA could significantly increase the contents of 5-HT, NE and DA in the brain tissues of aged mice. In vitro experiments revealed that the inhibition of WEPA on MAO-B was competitive, but on MAO-A was of mixed-type.

Aging↗
PubMed1992

[Investigation of microbicidal activity of neutrophil defensins against leptospires].

Defensins play an important role in oxygen-independent microbicidal mechanisms of neutrophils. They are effective against many bacteria, fungi and enveloped viruses. However, the effect of defensins upon leptospires has not been studied. In the present report, human defensins (i.e. HNP, a mixture of HNP1, HNP2 and HNP3 were prepared from human polymorphonuclear neutrophils by chromatography on Sephadex G-100 and then on Biogel P-10. Rabbit defensin NP1 was purified from rabbit peritoneal granulocytes by preparative acid urea polyacrylamide gel electrophoresis. By using the most-probable-number procedure, HNP and NP1 were tested in vitro for the killing of leptospira interrogans serogroup icteroheamorrhagiae serovar lai strain 017. NP1 was highly effective. When leptospires of strain 017 were incubated with 1 microgram/ml of NP1 at 30 degrees C for 4 hours, > 99% of these organisms were killed. HNP was less potent than NP1, and at 50 micrograms/ml, it killed > 90% of leptospires. As is also the case for the killing of bacteria, NP1 was active against leptospires in nutrient-free buffer, whereas HNP required the addition of glucose. The data suggest that defensins could play a major role in the killing of leptospires by neutrophils.

Animals↗
PubMed1992

[The construction of genomic library of Alcaligenes faecalis and cloning of nifH gene sequence homologous to Klebsiella pneumoniae].

A genomic library of Alcaligenes faecalis A-15Hl which possesses rather high nitrogenase activity has been constructed. The total DNA of A. faecalis A-15 Hl was partially digested with Sau3AI. 13-20 kb of fragments recovered from agarose gel were cloned in bacteriophage EM-BL4 vector. A total number of 1.2 x 10(6) of recombinants was obtained. It is much beyond the desired capacity of a library. By using nifH gene of K. pneumoniae from plasmid pGB1 as probe, we have successfully screened the clone containing its homologous sequence. The recombinant bacteriophage DNA was digested with EcoRI. A 3.5 kb of hybridizing band appeared after southern blotting and then was cloned in pUC19 DNA. The result of southern blotting indicated that the recombinant plasmid clone contained nifH gene sequence of A. faecalis. This clone was named as pAFH.

Alcaligenes↗
PubMed1991

Frequent induction of mammary carcinomas following neu oncogene transfer into in situ mammary epithelial cells of susceptible and resistant rat strains.

Varying results have been reported on the role of neu oncogene in mammary carcinogenesis. In order to further address this issue, the activated neu oncogene was introduced into mammary epithelial cells in situ of both mammary carcinoma-susceptible Wistar Furth and resistant Copenhagen rats by infusing replication-defective recombinant retroviruses carrying the neu oncogene into the mammary gland lumen. At the highest virus titer tested, very high numbers of mammary carcinomas developed within 2 weeks in all exposed glands in both rat strains. When the virus titer was reduced, however, individual tumors occurred with varying latencies. In addition, not all of the neu-infected mammary cells progressed to form mammary carcinomas. These results suggest that while neu is a potent mammary transforming gene, either other events in addition to neu expression may be required for full malignant transformation or not all mammary ductal epithelial cells are able to be neoplastically transformed.

Animals↗
PubMed1991

Overcoming the activity of mammary carcinoma suppressor gene in Copenhagen rats by v-H-ras oncogene transfer into mammary epithelial cells in situ.

Susceptibility to mammary cancer in rats is genetically controlled by both susceptibility and suppressor genes. The Copenhagen (COP) rat strain is highly resistant to both spontaneous and induced mammary carcinogenesis. The resistant trait is due to the inheritance of an autosomal dominant allele termed mammary carcinoma suppressor (mcs) gene. To test whether the activity of mcs gene can suppress the transforming potential of an activated oncogene, we introduced v-H-ras oncogene into COP mammary epithelial cells in situ using a replication-defective retroviral vector. v-H-ras transfer caused the rapid development of mammary carcinomas at high multiplicities. Hormonal promotion further increased the penetrance of the activated ras gene. Compared with the mammary carcinoma-susceptible Wistar Furth (WF) rat strain, tumor development in the COP rat followed analogous kinetics. However, COP tumors were more differentiated and less locally invasive than were WF tumors. The possible role of the mcs gene in mammary differentiation is discussed.

Animals↗
PubMed1991

Androgen responsiveness of the murine beta-glucuronidase gene is associated with nuclease hypersensitivity, protein binding, and haplotype-specific sequence diversity within intron 9.

The tissue specificity and genetic variability of the murine beta-glucuronidase (GUS) response to androgen provide useful markers for identifying elements which underlie this responsiveness. While GUS is expressed constitutively in all examined cell types, kidney epithelial cells uniquely exhibit a manyfold yet slow rise in GUS mRNA and enzyme levels when stimulated by androgens. Three major phenotypes of this androgen response have been described among inbred strains of mice: (i) a strong response in strains of the Gusa haplotype, (ii) a reduced response in strains of the Gusb and Gush haplotypes, and (iii) no response, as observed in Gusor mice. These response variants define a cis-active element(s) which is tightly linked to the GUS structural gene. Nuclease hypersensitivity scans of kidney chromatin within and surrounding the structural gene revealed an androgen-inducible hypersensitive site in intron 9 of the gene in Gusa but not in Gusor mice. When a radiolabeled fragment of Gusa DNA containing this hypersensitive site was incubated with kidney nuclear extracts and then subjected to gel electrophoresis, two shifted bands were observed whose levels were dramatically higher in extracts of androgen-treated than in those of untreated Gusa mice. The shifted bands reflect binding of a kidney-specific factor(s) to a 57-bp region of complex dyad symmetry in Gusa and Gusor mice which is partially deleted in Gusb and Gush mice. This binding site is located approximately 130 bp downstream of a glucocorticoid response element sequence motif which is totally deleted in [Gus]or mice. Taken together, our results suggest that the androgen responsiveness of GUS in murine kidney epithelial cells is controlled by elements within the proximal end of intron 9 of the GUS structural gene.

Androgens↗
PubMed1991

[Androgen-like and anabolic action of Antheraea pernyi Guerin-Meneville Pas].

It has been found that the ethyl acetate extract isolated from Antheraea pernyi Pas is able to increase the weight of prostate-semina and levator ani muscle-bulbocavarnosus muscle of castrated mice. In addition, the extract also accelerates the growth of younger male mice and enhances the contents of RNA, DNA and protein in the liver tissue of mice. It has been determined that beta-ecdysone is one of the effective constituents for the androgen-like and anabolic action.

Animals↗
PubMed1991

[Screening and identification of monoclonal antibodies against human neutrophil and detection of inhibiting opsonic phagocytic activity].

Using Ficoll-Hypaque gradient centrifugation, we have successfully obtained the neutrophils from normal human donors, which can be used as particle antigens for immunizing BALB/c mice. Hybridomas were produced through the fusion of SP2/0 myeloma cells and splenocytes from immunized BALB/c mice. The ratio of fusion was 1:5. The cells were fused with 30% polyethylene glycol (MW 4000). The rate of fusion was 90%. The antibody producing colonies against the membrane of neutrophils in HAT medium were selected by indirect immunofluorescence assay. Antibody positive rate was 60% (102/170). Limiting dilution was used for colonization of the antibody-producing hybridoma cells. After colonization for three times, one hybridoma cell line was obtained, which could inhibit complement-mediated phagocytosis. Culture supernatant was used against class- and subclass- specific rabbit antisera (rabbit anti-mouse IgM, IgG, IgG1, IgGd22, IgG2b, IgG3) in an agar immunodiffusion system, it was shown to be IgG22.

Animals↗
PubMed1991

[Preliminary studies of notoginsenoside R1-induced differentiation of HL-60 cell lines in vitro].

Our experiments have proved that human promyelocytic leukemia cells (HL-60) could be induced to differentiate in vitro by notoginsenoside R1 into mature neutrophils. The morphological results showed that 68% of HL-60 cells were differentiated in 80 microgram/ml inducer for 5 days, in which metamyelocytes were 32%, banded neutrophils 30% and segmented neutrophils 6% 3H-TdR and 3H-UR incorporate assay showed that notoginsenoside R1 effected synthesis of DNA and RNA while it induced differentiation of HL-60 cell. At 48 h, percent of incorporate inhibition was 26.32% with 3H-TdR and 18.57% with 3H-UR; at 72 h, 17.46% and 21.76%, respectively.

Antineoplastic Agents, Phytogenic↗
PubMed1991

[The structure of glyeurysaponin].

A species of the genus Glycyrrhiza, G. eurycarpa P.C. Li recently reported as a new species growing in Gansu Province Xinjiang Autonomous Region has rarely been studied before on its chemical constituents. This paper reports the isolation and chemical elucidation of two triterpene glucosides named glyeurysaponin (K-4) and uralsaponin B (K-3) from this species collected in Jinta County, Gansu Province. Their chemical structures were elucidated by means of chemical and spectrometric analysis (UV, IR, MS, 1HNMR and 13CNMR) and were first reported to be present in this plant. Glyeurysaponin (K-4), C42H62O16 was obtained as white crystals, mp 288 degrees C (d), [alpha]18D + 22.5 degrees (c 0.62,60%MeOH). Its structure was found to be be 3 beta-hydroxy-11-oxo-olean-12-en-30-oic acid-3-O-beta-D-glucuronopyranosyl-(1----4)-beta-D-glucuronopyr anoside. Glyeurysaponin is a new triterpenoid saponin. The known saponin was identified to be 3 beta-hydroxy-11-oxo-olean-12-en-30-oic acid-3-O-beta-D-glucuronopyranosyl-(1----3)-beta-D-glucuronopyr anoside, uralsaponin B.

Glycyrrhiza↗
PubMed1991

A morphological study of primary pulmonary hypertension--an analysis of six autopsy cases.

Six typical autopsy cases of primary pulmonary hypertension are reported. The histopathological features were as follows: medial hypertrophy of the muscular pulmonary arteries, muscularization of arterioles, internal fibrosis and fibroelastosis of muscular pulmonary arteries with typical "onion-skin" configuration, fibrinoid necrosis of the media or necrotizing arteries of muscular pulmonary arteries, and formation of highly characteristic plexiform lesions and dilatation lesions. It is thought that the plexiform lesions seen in all six cases represent morphological changes resulting from pulmonary hypertension rather than congenital abnormalities or thromboembolism.

Adult↗
PubMed1991

[Effect of the human leukocyte angiotensin II-like substance (LATII-LS) on isolated rabbit carotid arteries].

The presence of angiotensin II-like substance (LATII-LS) in the human leucocytes was identified by means of immunofluorescence technique. And the LATII-LS PURIFIED purified by high-power liquid chromatography (HPLC). The effect of LATII-LS on isolated rabbit carotid arteries showed a definite vasoconstrictive character. It was surmised that this would play a role in causing the cerebral vasospasm after spontaneous subarachnoid hemorrhage.

Angiotensin II↗