Biomedical subjects

S Bi

Publications and source records attributed to S Bi.

At least 37 records · Page 2Linked to original sources

PubMed1998

[Quantitative and objective evaluation of vocal function after vertical hemilaryngectomy].

The lately invented instrument, phono laryngograph, which can evaluate objectively vocal function, was used to determine separately in 30 normal adults and 30 patients with laryngeal carcinoma treated primarily by vertical hemilaryngectomy from 1984 to 1994. The results showed that mean air flow rate, intensity, MPT, have significant difference between surgical groups and normal group (P < 0.01). There is pitch difference between surgical groups and normal group (P < 0.05). We also found that the determined values have significant difference between postoperative two years and postoperative ten years groups (P < 0.01).

Adult↗

PubMed1998

[Chimpanzee model of hepatitis E virus infection].

For the study of the hepatitis E virus infection animal model, two chimpanzee were inoculated with hepatitis E virus. After one month of the inoculation, the animal got typical hepatitis profile. ALT, anti virus-IgM, antivirus-IgG, were detected in detail. The results showed solid HEV infection evidence of typical hepatitis within one month after the inoculation.

Alanine Transaminase↗

PubMed1998

[Genome shift of hepatitis E virus in Asia].

Dideoxy chain termination method was applied to sequence hepatitis E virus structure gene of Asia isolates, cDNA sequence and amino acid residues were determined. The results showed that among Asia countries: Indian, Burma, China, Pakistan and Kirghiz Republic, Hepatitis E virus genome shifted within the range of 5% and amino acid residues shifted within 1% compared with Mexico isolate. Asia Hepatitis E virus isolates have limited genome shift, which suggests recombinant Hepatitis E vaccine based on Asia HEV gene might protect all HEV infection in this area.

Amino Acid Sequence↗

PubMed1998

[Indirect sensitized upconversion in Tm3+ and Yb3+ codoped non-crystal pentaphosphate].

We report the blue upconversion luminescence of Tm3+ and Yb3+ codoped non-crystal pentaphosphate pumped by -798nm laser diode. The samples were directly excited to 3F4 level of Tm3+ ion. Two energy transfer processes between Tm3+ and Yb3+ contribute mainly to the population of 1G4 level of Tm3+. Phonon plays an important role in the upconversion process.

English Abstract↗

PubMed1997

Identification of a placental enhancer for the human leptin gene.

Leptin is a hormone that regulates metabolic efficiency, energy expenditure, and food intake. Leptin is produced chiefly in adipose cells, but in humans, mRNA encoding leptin is also present in the placenta. Here we elucidate the basis for placental leptin production. The same promoter is used for adipose and placental transcription. An upstream enhancer functions in the JEG-3 and JAR choriocarcinoma cell lines but not in adipocytes or HeLa cells. The minimal positive acting region is 60 base pairs in length. This region is within a MER11 repetitive element, suggesting that human placental expression of leptin is the result of insertion of this element. Binding analyses demonstrated three protein binding sites, designated placental leptin enhancer elements (PLE)1, PLE2, and PLE3. PLE2 binds Sp1. Enhancer activity was reduced by mutation of the PLE1 or PLE3 sites but was unaffected by alteration of PLE2. Proteins binding to PLE3 were present in JEG-3 and human placental nuclear extracts but not in extracts from non-placental sources. Upon triplication, the PLE3 element was a strong enhancer in choriocarcinoma cells but not in HeLa cells. The protein binding to the PLE3 motif appears to be a novel, placenta-specific transcription factor.

Base Sequence↗

PubMed1997

Cytokines, molecular biological abnormalities, and acute myelogenous leukemia.

Leukemia cell proliferation is dependent upon cytokines produced by the leukemia cells or by the microenvironment under stimulation by leukemia cells. Abnormal expression of the p53, rb, and ras genes is associated with cytokine production, suggesting that abnormal expression can affect leukemia cells by affecting intracellular growth controls and by stimulating cytokine production. While these observations suggest that cytokines can be used to stimulate leukemia proliferation during cytotoxic therapy increasing the sensitivity to treatment, they also suggest that inhibition of cytokine affects could increase clinical responses by reducing leukemia cell regrowth between courses of therapy.

Animals↗

PubMed1997

[cDNA cloning, sequencing and expression of recombinant human prorelaxin].

In order to accelerate the development of biological recombinant human prorelaxin in our country, direct cloning of human prorelaxin gene from freshly prepared corpus luteum of Chinese woman by RT-PCR method was conducted. Isolated prorelaxin gene contains B, A chains and connective peptide. The amplified products were cloned and confirmed by DNA sequencing using Sanger Dideoxy method. It was subcloned into LKB2, a prokaryotic expression vector offering promoter LacI control, and highly expressed in E. coli. The results suggest that the PCR amplified DNA fragment shared identical sequence with known prorelaxin gene reported abroad. The SDS-PAGE analysis revealed that the expressed protein accounted for about 30% of the total cell protein, its MW was approximately 20 kD and conformed soluble protein.

Cloning, Molecular↗

PubMed1997

[Diagnosis of hepatitis E virus infection in sporadic acute hepatitis].

The solid-phase enzyme immunoassay (EIA) was used for detecting anti-HEV immunoglobulin G (IgG) and M (IgM) by using a recombinant chimeric antigen (ORF3-2) from the open reading frame (ORF) 2 and 3 of hepatitis E virus gene. These sera were collected from the patients with sporadic acute viral hepatitis. The positive rate for anti-HEV IgG was 15.22% (7) among 46 patients with acute hepatitis, 5 of the 7 IgG positive sera were also positive (71.4%) for anti-HEV IgM. 91.8% (93) and 76.4% (78) were positive separately for anti-HEV IgG and IgM among 102 patients of suspected HEV infection (these patients were negative for anti-HAV, anti-HBV and anti-HCV), about 2/3 patients of HEV infection detected were simultaneously HEV-IgG and IgM positive. In control group of 98 normal persons, 4 (4.08%) were positive for anti-HEV IgG, but none were IgM positive. Paired sera of the patients in the acute phase and convalescent phase were detected, the titers of anti-HEV IgG with 4-16 fold decrease were seen in 6 cases and with 2-fold rise in 1 case.

Acute Disease↗

PubMed1997

[Synthesis of N-salicylidene leucine 3d metal complexes and studies on their thin-layer chromatography and ultraviolet spectrum].

The Schiff base derived from salicylaldehyde and leucine and its Mn(II), Co(II), Ni(II), Cu(II), Zn(II) complexes were synthesized. The purity of the products obtained was confirmed by elemental analysis. The results of elemental analysis and molar conductance show that coordination ratio with M(II) is 1:1 and its complexes are non-electrolyte in DMF. The thin-layer chromatography behavior of complexes was studied on silica gel G plate with ethyl acetate-methanol-acetone-water-acetic acid (4.44:3.33:2.22:0.25:0.12, V/V) as mobile phase. The results show that the Rf value of complexes increases as follows Mn<Zn<Ni<Cu<Co. The lambda(max) values of ultraviolet spectra of ligand and complexes are determined in methanol and DMSO. The lambda(max) values of complexes increase as follows: Mn(II)<Zn(II)<Ni(II)<Cu(II)<Co(II)<ligand. The Rf values and R band lambda(max) values of complexes change in the same direction as the stability constants of the complexes. This proves that the Rf values of complexes on silica gel G and R band lambda(max) values of complexes depend on coordinaton of M(II) with ligand.

Chromatography, Thin Layer↗

PubMed1996

Genomic structure and promoter analysis of the human obese gene.

The human gene encoding the homolog of the mouse obese (ob) gene was isolated and partially characterized. The human ob gene consists of three exons and two introns and spans about 18 kilobase pairs (kb), encoding a 3.5-kb cDNA. A 3-kb 5'-flanking region of the gene was cloned and transient transfection assay with luciferase reporter confirmed the promoter activity in differentiated F442-A adipocytes. Potential regulatory elements are discussed in this report.

Adipocytes↗

PubMed1996

A model describing the complexing effect in the leaching of aluminum from cooking utensils.

A simple model describing the complexing effect in the leaching of aluminum from cooking utensils is presented in this paper. Some experimental results obtained by previous workers may be explained by this model, which demonstrates that the complexing effect takes a very important role in the process of aluminum liberated from cooking utensils. Increased concentrations of complexing ions (organic acids, fluoride ion, OH-, etc.) significantly enhance the release of aluminum. The speciation of aluminum in simulated food solution is also investigated. The model suggests that in the pH range of most food (pH 4-8) aluminum present is predominantly in the form of organic Al-complexes, which is harmful to the human body.

Journal Article↗

PubMed1995

Role of p53 in leukemogenesis of chronic myeloid leukemia.

This review attempts to provide current information on the role played by the p53 gene in normal and leukemic hematopoiesis with particular emphasis on chronic myeloid leukemia. On the basis of the currently available data we can argue that p53 acts as a negative regulator of proliferation of myeloid mature cells and CD34+ progenitors, and its action is mediated through changes in cell cycle kinetics, mainly before the S phase. The p53-dependent pathway is also regulated by several proteins, including p16, p21, p27 (cyclin-dependent kinase [CDK] inhibitors), and a few oncogenes (bcl-2, bax, MDM-2). Although there is some information about the changes in the p53 gene seen in various types of leukemia, the functions and biological importance of these changes in the pathogenesis of leukemia are still largely elusive. During the past several years, accumulated evidence suggests that changes in the p53 gene are commonly associated with blast crisis of chronic myeloid leukemia (CML) but rarely with chronic phase, and they are represented by rearrangements, deletions and point mutations. As for most of the tumors, the majority of point mutations occur between exons 4 and 8 (hot regions). In patients with CML in blastic crisis the most frequent mechanism of p53 inactivation is complete deletion of one allele in association with a point mutation in the remaining allele.(ABSTRACT TRUNCATED AT 250 WORDS)

Genes, p53↗

PubMed1995

Modulation of cell kinetics and cell cycle status by treating CD34+ chronic myeloid leukaemia cells with p53 antisense phosphorothioate oligonucleotides.

Mutations of the p53 tumour suppressor gene occur in 20% of chronic myeloid leukaemia (CML) patients in blastic crisis, but it is still uncertain whether this inactivation plays a role in the pathogenesis of blastic transformation or in maintaining the leukaemic proliferation in CML, as it does in several solid tumours. We have previously shown that more than 50% of both normal and CML CD34+ cells express the p53 protein. However, haemopoietic cells at different phases of the cell cycle express p53 with different conformations, suggesting that the function of p53 may be closely regulated during the cell cycle. In order to elucidate the mechanism by which p53 suppresses cell proliferation, we evaluated the effects of inhibiting p53 expression on cell cycle and cell kinetics of chronic phase CML (n = 12) and normal (n = 7) bone marrow light-density cells and purified CD34+ progenitors by using an 18-mer modified antisense oligonucleotide which targets the region covering the six base pairs immediately before the first codon and the first four coding codons of p53. We found that the number of cells positive for the cell cycle-specific nuclear antigen Ki67 and for the BrdU monoclonal antibody (McAb) was significantly increased after p53 antisense olignucleotide treatment. At the same time, p53 protein expression was completely abrogated in both light-density and CD34+ cells. In addition, DNA analysis by flow cytometry demonstrated that the number of cells in quiescent phases of the cell cycle (G0-G1) was significantly decreased after exposure of light-density cells to p53 antisense oligomers, whereas the number of cells in S or G2-M phases was increased. Furthermore, the longer the incubation time the higher the increase in cell proliferation. Treatment of CML, cells with p53 antisense oligomers also resulted in significantly increased numbers of CFU-GM colonies. Our data suggest that p53 is a negative regulator of cell proliferation and its action is mediated through changes in cell cycle kinetics, mainly before the S phase. We can further speculate that the loss of p53 function, at the time of blastic crisis of CML, may play a role, in combination with other genetic changes (p210 BCR/ABL, Rb gene abnormality, others to be defined), in inducing disturbances in cell proliferation, differentiation, and apoptosis.

Adult↗

PubMed1995

Antiulcer effect of diltiazem in rats.

AIM: To study the effects of diltiazem (Dil) on several experimental gastric ulcers in rats. METHODS: The gastric mucosa damage was induced by indometacin (Ind), restraint, pyloric ligation, and absolute ethanol in rats. Dil 5, 25, 50 mg . kg-1 ig bid for 5 times. The number of gastric ulcers, the secretion of gastric juice, hydrochloric acid (HCI), and pepsin A were detected. The production of malondialdehyde (Mal) and the activity of superoxide dismutase (SOD) in gastric mucose were examined. RESULTS: Dil 5, 25, 50 mg . kg-1 ig protected the gastric mucosa against the damages in a dose-dependent manner. Dil inhibited the secretion of gastric juice, HCI, pepsin A, and Mal production of the gastric mucosa, but increased the activity of SOD in the gastric mucosa. The production of Mal was decreased from 9.3 +/- 3.7 to 6.5 +/- 1.9 mumol/g wet weight (P < 0.05) and the activity of SOD was increased from 6.1 +/- 5.6 to 12.8 +/- 2.8 kU/g protein (P < 0.01) by Dil 50 mg . kg-1. CONCLUSION: The inhibition of gastric secretion and lipid peroxidation induced by oxygen free radicals of gastric mucosa was related to the antiulcer effect of Dil in rats.

Animals↗

PubMed1994

The involvement of "tumor suppressor" p53 in normal and chronic myelogenous leukemia hemopoiesis.

We investigated the expression of p53 in paraformaldehyde-lysine-periodate fixed normal and chronic myelogenous leukemia (CML) hemopoietic cells with flow cytometry and two monoclonal antibodies, PAb1801 and the mutant-conformation-associated PAb240. With both antibodies p53 proteins were detected in more than 50% of CD34+ cells and in more than 95% neutrophils but were undetectable in the CD34- myeloid precursors. The expression of a p53 protein reactive with PAb240 was closely associated with CD34+/HLA-DR+ cells and with cells in active cell cycle, while the p53 protein recognized by PAb1801 was mainly found in CD34+/HLA-DR- cells and in cells in the G0/G1 phases of the cell cycle. Treatment of chronic-phase CML cells with p53 antisense oligonucleotides resulted in significantly increased numbers of granulocyte-macrophage colony-forming unit colonies in 12 of 17 cases studied. Slightly reduced granulocyte-macrophage colony-forming unit colony numbers were observed in one case and no change in the four others. In eight samples of normal bone marrow cells, treatment with antisense oligonucleotides showed no consistent changes in granulocyte-macrophage colony-forming unit numbers. Our data suggest that the expression of the tumor suppressor p53 is involved in the regulation of both normal and CML hemopoiesis and that the inhibition of p53 expression could modulate the proliferation of CML hemopoietic cells and possibly of normal cells.

Base Sequence↗

PubMed1994

[Digital subtraction angiography in otorhinolaryngology--preliminary report].

The paper presents the preliminary experience with digital subtraction angiography (DSA) in otorhinolaryngology. This series included racemose hemangioma of the auricle in 3 cases, juvenile angiofibroma of nasopharynx in 4 cases, angioma in the retropharyngeal space in 1 case, tympanic body tumor in 1 case, traumatic epistaxis in 1 case, traumatic pseudoaneurysm in 1 case. The site, supply arteries, drainage veins of vascular tumors were shown with DSA. The intraoperative bleeding was reduced significantly by preoperative embolization of supply arteries to vascular tumors. The broken arteries of the traumatic epistaxis and the traumatic pseudoaneurysm were not only discovered but embolized. The indications and complications of DSA and measures for preventing and reducing complications were discussed.

Adult↗

PubMed1994

[Study on influence degree of probability of endemic factors for schistosomiasis transmission in Yunnan mountainous regions].

In Zhonghe Village of Weishan County, Yunnan Province, a schistosomiasis endemic area of mountainous valley subtype, an epidemiological investigation was conducted on its natural, biological and social factors influencing schistosomiasis transmission in 1987-1990. The results were analyzed by stratified sampling analysis and probability accumulation method. It was demonstrated that 12 of 29 factors were the most important factors influencing schistosomiasis transmission including annual average air-temperature, number of infection sources, number of spots with infected snails, water temperature and annual average rainfall, etc. The values of influence degree before and after intervention measures were 3.513 and 2.066, respectively, the decrease being 41%.

Animals↗

PubMed1994

Retroviral transduction of Philadelphia-positive chronic myeloid leukemia cells with a human mutant p53 cDNA and its effect on in vitro proliferation.

Alterations in the tumor suppressor gene p53 are associated with the pathogenesis of blastic transformation of chronic myeloid leukemia (CML), but their exact role, particularly their relationship with the chimeric protein p210BCR/ABL, is poorly defined. Point mutations in p53 have been found in some cases of blast crisis and CML blastic cell lines, but it is not clear whether complete inactivation of p53 tumor suppressor function, with or without the production of a mutant protein, can by itself trigger the process of blastic transformation. By using retroviral gene transfer, we showed that the introduction of a mutant human p53 cDNA into hematopoietic progenitor cells from patients with CML in chronic phase, which already contain p210BCR/ABL, could promote their proliferation in vitro, and occasionally even lead to the growth of factor-independent colonies. We conclude that a mutant p53 may act in synergy with p210BCR/ABL and promote the survival and proliferation of CML hematopoietic stem and progenitor cells in vitro.

Cell Division↗