Biomedical subjects

B Chen

Publications and source records attributed to B Chen.

At least 271 records · Page 15Linked to original sources

PubMed1999

[Clone and tissue expression of tree shrew apolipoprotein AI cDNA].

OBJECTIVES: To clone apolipoprotein AI (apoAI) gene from tree shrew (TS) which is an animal insusceptible to atherosclerosis and to analyze the characteristics of the gene. METHODS: A cDNA library of the liver tissue was constructed by using the isolated mRNA as the template during reverse transcription. The positive clones of apoAI cDNA were identified in the library with an anti-serum to TS apoAI. Sequencing, analyzing and expressing of the clones were finished. RESULTS: A complete cDNA sequence of TS apoAI was determined as 900 nucleotides. It contained 28 bp in 5' untranslated region, and 795 bp in an open reading frame encoding a 265-amino acid apoAI precursor (an 18-amino acid signal peptide, a 6-amino acid propeptide and a 241-amino acid mature protein), two stop codens (TGA, TAA) and following 72 bp in 3' untranslated region. The novel gene was submitted to GenBank. TS apoAI deduced from the cDNA sequence was more hydrophobic than that of human. The results of Northern blot indicated the plentiful presence of apoAI mRNA in TS liver and intestine. CONCLUSIONS: A new gene was cloned from TS, one animal insusceptible to atherosclerosis. TS apoAI may have a stronger activity of binding cholesterol and cholesterol ester than that of human apoAI in reverse cholesterol transport. A good foundation was laid for studying the molecular structure and function of TS apoA I.

Amino Acid Sequence↗

PubMed1999

[Relationship of cytokines and cold-heat syndrome differentiation in patients of duodenal ulcer].

OBJECTIVE: To explore the relationship of cytokines and Cold-Heat Syndrome in patients of duodenal ulcer. METHODS: Cold-Heat Syndrome Differentiation was done in 48 patients of duodenal ulcer, and the levels of interleukin-8 (IL-8), interleukin-6 (IL-6), tumor necrosis factor (TNF), malonyldialdehyde (MDA), marrow peroxidase (MPO) in gastric mucosa biopsy were measured and compared with those of 10 normal subjects. RESULTS: Levels of IL-8, TNF, MPO and MDA in Heat Syndrome were higher than those in Cold Syndrome (P < 0.05), while IL-6 level showed no significant relationship with Cold-Heat Syndrome. CONCLUSION: Cytokines IL-8, TNF, MPO and MDA are correlated with Cold-Heat Syndrome in duodenal ulcer patients and which might be one of the molecular mechanisms of Cold-Heat Syndrome Differentiation.

Adult↗

PubMed1999

[Evaluation of potential harmful effects of organic pollutants in tap water on mice in vivo].

OBJECTIVE: To study the harmful effects of organic concentrates from tap water on mammal animals in vivo. METHODS: Organic pollutants were absorbed with resin XAD-2 from tap water and administered the mice via a stomach tube or intraperitoneal injection. Micronucleus rate in bone marrow polychromatic erythrocytes, testicular chromosome aberration rate, indices for immune functions and the activity of ethoxyresourufin o-deethylase (EROD) in S(9) fraction of the liver were determined. RESULTS: Micronucleus rate and chromosome aberration rate increased by 1.7 and 3.5 folds, respectively, after administration of high dose of organic pollutants from the tap water (200 liters of tap water per kilograms of body weight) for three days. Humoral immunity and non-specific immune functions were obviously inhibited after administration of low-dose (6 L/kg). In addition, organic concentrates from tap water also could significantly induce the activity of EROD, with a good dose-dependent relationship. CONCLUSION: Organic concentrates from tap water could cause chromosome damage to somatic and germ cells and decrease in immune functions in the mice, as well as they could induce the activity of cytochrome P448 in the liver microsome. It suggested that organic pollutants concentrated from tap water had potential carcinogenic effects on mammal animals.

Animals↗

PubMed1999

[Effect of fodder components on the product of obese gene expression--leptin in rats].

OBJECTIVE: To study the effects of different fodder components and levels of caloric uptake on the product of obese gene expression -- leptin and in vivo secretion of insulin and growth hormone, and to study the relationship between them in rats. METHODS: Plasma leptin was determined by Western blot, and serum insulin and growth hormone were determined by radioimmunoassay (RIA). RESULTS: There was no significant effects of fodder components, including high protein, fat and carbohydrate, on the levels of leptin, insulin and growth hormone in rats, with the same caloric uptake in them. However, with the higher caloric uptake, level of obese gene expression increased, showing increased levels of plasma leptin and serum insulin and decreased level of serum growth hormone. CONCLUSION: There could existed an interaction between expression of obese gene and secretions of leptin, insulin and growth hormone, which could be modified by the same metabolic signal.

Adipose Tissue↗

PubMed1999

[Studies on changes in levels of hormone and expression of ob gene during induction of obesity in rats].

OBJECTIVE: To study the rules of changes in ob mRNA and its relation to hormone level in vivo in rats during their dynamic process to obesity induced by high-caloric fodder. METHODS: Level of ob mRNA in adipose tissues of rats was determined with dot-hybridization techniques, and levels of serum insulin and growth hormone were measured with radioimmunoassay. RESULTS: Level of ob mRNA in the fatty tissues and serum insulin level increased, but serum level of growth hormone decreased, with the increase in body weight of rats. CONCLUSION: Increase in expression of ob mRNA could be the result, but not the cause, of obesity. Changes in the levels of ob mRNA, serum insulin and growth hormone indicated that they could affect each other and could be regulated by common metabolic signals.

Adipose Tissue↗

PubMed1999

[The role of the leukocytes in pathogenesis of secondary brain injury].

The levels of leukocyte count, neutrophil number, leukocyte adhesiveness, leukocyte releasing oxygen-free radical (O2.-) after phagocytosing bacteria and serum lipid peroxide MDA were determined in the peripheral blood of 40 patients with acute head injury within 48 hours and 22 normal adults. These levels of patients were significantly higher than those of the controls (P < 0.05), and increased with the severity of craniocerebral injury elevation. The leukocyte count and neutrophil number of those patients who died were significantly higher than these of those survived patients (P < 0.05). It suggested that leukocytes aggravated the secondary brain injury after craniocerebral injury by increasing of leukocyte adhesiveness, and generating and releasing oxygen-free radical, and measurement of leukocyte count and neutrophil number in the peripheral blood could evaluate the prognosis of the patient with craniocerebral injury.

Adolescent↗

PubMed1999

[Enhanced cytotoxicity of VM-26 in human malignant glioma cells by calcium channel blocker nicardipine in vitro].

Using the monolay tumor cell culture system and the method or MTT colorimetric analysis, the cytotoxicity of the anticancer drug VM-26 and Nicardipine(NCDP) in human malignant glioma cell line U251 was studied. The results showed that the cytotoxicity of VM-26 in U251 was enhanced by NCDP at a low dose which did not show direct cytotoxicity. The authors considered that VM-26 combined with NCDP can heighten the intracellular anticancer drug concentration, reverse the drug resistance and heterogeneity in human malignant glioma cells. The mechanism of the enhanced effect was also discussed. These findings will provide an alternative chemotherapeutic clue to treat the postoperative malignant gliomas.

Antineoplastic Agents↗

PubMed1999

[Inhibitory effect of conjugated linoleic acid on human gastric carcinoma cell line].

The effects of conjugated linoleic acid (CLA) on human gastric carcinoma cell line (SGC-7901) were studied in cell culture. The four levels of CLA in medium were designed as 25, 50, 100 and 200 mumol/L, and the dissolvent control being ethane. The result displayed that CLA could inhibit the cell proliferation, cellular mitosis, cell clone formation and DNA synthesis and induce cellular differentiation of SGC-7901 cells.

Adenocarcinoma↗

PubMed1999

[The experimental study of membrane-guided tissue regeneration of bone].

OBJECTIVE: To confirm membrane-guided tissue regeneration in the healing course of segmental bone defects and study the mechanism. METHODS: Segmental, 1 cm osteoperiosteal defects were produced in both radii of 12 rabbits. One side was covered with hydroxyapatite/polylactic acid(HA/PLA) membrane encapsulated as a tube. The contralateral side served as an untreated control. Healing courses were detected by radiographic and histologic examinations. RESULTS: All control sides showed nonunion, whereas there were consistent healing pattern in test sides. CONCLUSION: Membrane technique can promote bone regeneration.

Animals↗

PubMed1999

[Clinical usefulness of serum IFN-gamma level in patients with chronic obstructive pulmonary disease].

The objective of this study was to gain a clear idea of rule of change in serum IFN-gamma level in patients with chronic obstructive pulmonary disease and to evaluate the clinical usefulness of IFN-gamma as a marker of immune condition. The serum IFN-gamma levels of 15 patients with chronic bronchitis, 15 patients with cor pulmonale, 15 patients with acute bronchitis, and 15 normal subjects were measured by radio-immuno-assay. Differences between the four groups were tested, and in the chronic bronchitis group, the serum IFN-gamma levels, before and after treatment were compared. The results showed that compared with the normal group (0.8 +/- 0.17 IU/ml), the serum level changed little in the cor pulmonale group (0.93 +/- 0.25 IU/ml); it was not higher in the chronic bronchitis group (1.23 +/- 0.39 IU/ml, P > 0.05), but it went up significantly after treatment for 7 days (1.84 +/- 0.51 IU/ml, P < 0.05). The highest level of IFN-gamma was noted in the acute bronchitis group (2.24 +/- 0.71 IU/ml, P < 0.01). There was a significant difference compared with other groups (P < 0.01). These results suggest that relative deficiency of serum IFN-gamma may be a factor inducing repeated respiratory infection, and the serum level of IFN-gamma can be used as an index to assess the immune condition of patients with chronic obstructive pulmonary disease.

Biomarkers↗

PubMed1999

[Transantral orbit decompression to malignant ophthalmopathy].

OBJECTIVE: To recognize the indication and the value of transantral orbit decompression to malignant ophthalmopathy. METHOD: 9 eyes of 5 cases undergone transantral orbital decompression from November 1986 to October 1998 were reviewed. RESULT: After 3 months-2 years of follow-up. We found this approach successfully improved visual function of all 5 cases. Average proptosis reduction was 5 mm. The eye lids could be closed in 4 of the 5 cases and the palpebral fissures was decreased 1-2 mm in 1 of the 5 cases. Preoperative exposure keratitis resolved in both of the 2 cases. Diplopia was cured in both of the 2 cases. Secondary glucorna also recovered in both the 2 cases. Disturbance of ocular motility in both of the 2 cases improved postoperatively and preoperative visual acurity worsen also improved in both of the 2 cases. CONCLUSION: It has been suggested that the transantral decompression of the orbit provided a safe, effective therapeutic modality for patients with vision-threatening or major cosmetic problem.

Adult↗

PubMed1999

[Analysis of physicochemical property and composition of fatty acid of almond oil].

Almond oil was extracted from almond and saponified with saturated KOH-methanol. The mixed fatty acids methylated by methanol-H2SO4(4:1, V/V). Methyl esters were extracted by ether and detected by gas chromatography. The major fatty acids in Taiyuan almond oil were found to be about 68% oleic acid (C18:1), 25% linoleic acid(C18:2), 4.6%-4.8% palmitic acid(C16:0) and a little of palmitoleic acid(C16:1), stearic acid(C18:0). A trace of arachidic acid(C20:0) was also found.

Chromatography, Gas↗

PubMed1999

[An experimental study about tiny traumatic measurement of the facial nerve fluid pressure].

OBJECTIVE: To study endoneurial fluid pressure (EFP) in facial nerve of normal state. METHOD: EFP was recorded by an active, servo-nulling pressure system in 24 normal guinea pigs. RESULT: The results showed that EFP of the facial nerve was 2.87 +/- 0.51 mmHg and 2.70 +/- 0.43 mmHg in the tympanic and mastoid segment respectively. EFP in the tympanic part was similar to that of mastoid segment. In addition, EFP of facial nerve revealed rhythmic fluctuation within limits. CONCLUSION: It was suggested that measurement of facial nerve pressure by a servonulling system should be useful in evaluating the pathogenesis undelying facial palsy.

Animals↗

PubMed1999

[Studies on the infrared spectra of mico2-OR or micro2-SR-bridged double-cubane-like clusters containing MoFe3S4 cores].

The IR spectra of micro2-OR or micro2-SR- bridged double-cubane-like clusters containing MoFe3S4 cores (Et4N)3 [Mo2Fe6S8Cl6 (OMe)3] (1), (Et4N) [Mo2Fe6S8 (SPh)6 (OMe)3 (2), (Bu4N)3 Mo2Fe6S (SPh)6 (OMe)3] (3), (Et4N)3 [Mo2Fe6S8 (SBu(t))6(OMe)3](4), (Et4N)3[Mo2Fe6S8 (SPh)9](5) have been investigated. Their characteristic frequencies (v)Mo-micro2O(R), (v)Mo-micro2S(R), (v)Mo-S, (v)Fe-S*, (v)Fe-SR, (v)Fe-Cl were assigned by comparing their vibrational frequencies with their structural parameters and by comparing the IR spectra of them with that of the linear clusters. The electrophilic induced effects in different way and the relationship between deltav (i.e. (v)Mo-S* (v)Fe-S*) and Fe --> Mo charge transfer have been discussed. Finaly, the sameness and difference between the double-cubane-like and linear Mo-Fe-S clusters were demonstrated.

English Abstract↗

PubMed1999

[Transmission grating spectrograph for soft X-ray spectrum measurements with a pre-optics].

A novel diffraction spectroscopic instrument consisting of a large area transmission grating and a grazing-incidence pre-optics comprising of a toroidal mirror, a slit and a cylindrical mirror has been implemented. A nearly perfect stigmatism and a medium spectral resolution are due to the separation of the focusing and dispersing function. The experimental results show that it is possible to construct large area transmission grating spectrograph with high collecting efficiency and good spatial resolution.

English Abstract↗

PubMed1998

A mAb recognizing a surface antigen of Mycobacterium tuberculosis enhances host survival.

Murine mAbs reactive with the surface of Mycobacterium tuberculosis were assayed for their ability to affect the course of infection in mice challenged with virulent organisms. An IgG3 mAb (9d8) specific for arabinomannan and reactive with purified antigen from a clinical isolate of M. tuberculosis conferred partial protection on mice after respiratory challenge (30-60% survival >75 days; P </= 0.05). Control mice pretreated with an irrelevant mAb of the same isotype succumbed to tuberculosis within 30 days. Mice with gene disruptions in interferon gamma and major histocompatibility complex Class II also were partially protected from challenge. The protective mAb was neither bactericidal nor inhibitory of infection or bacterial replication. Nevertheless, it profoundly altered the nature of the granulomas in the infected lungs. Mice treated with mAb 9d8 and challenged with M. tuberculosis localized the pathogen within granuloma centers, suggesting that the mAb conferred protection by enhancing a cellular immune response.

Animals↗

PubMed1998

[Association between the debrisoquine hydroxylase gene polymorphism and the genetic susceptibility of Parkinson's disease].

OBJECTIVE: To clarify the relation of the debrisoquine hydroxylase gene polymorphism with the genetic susceptibility of Parkinson's disease. METHODS: The debrisoquine hydroxylase gene polymorphisms were analyzed with the polymerase chain reaction-restriction fragment length polymorphism methods in 100 cases of Parkinson's disease and 100 age-,sex-matched normal controls. RESULTS: It was found that the frequencies of A and B mutation of debrisoquine hydroxylase gene in group of patients were higher than those in the controls, and the risk of suffering Parkinson's disease increased 2 times. In group of the patients, the frequencies of C188-->T, G4268-->C and C2938-->T were also higher than those in the controls. Especially in those with C2938-->T mutation, the risk of suffering the disease increased 2.58 times. CONCLUSION: The result suggested that the defect of the detoxifying enzymes might be a factor contributing to the genetic susceptibility of Parkinson's disease.

Adult↗

PubMed1998

[Relationship between methylenetetrahydrofolate reductase gene polymorphism and coronary heart disease].

OBJECTIVE: This study inquired into the relationship between methylenetetrahydrofolate reductase (MTHFR) gene polymorphism and coronary heart disease. METHODS: By polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP), MTHFR 677C-->T mutation was detected in 79 healthy controls and 69 patients with coronary heart disease. RESULTS: The frequency of MTHFR variant V677 of patients was significantly higher than that of healthy controls (P<0.01). CONCLUSION: This study demonstrated that MTHFR gene V677 mutation was probably one of the genetic risk factors of coronary heart disease and this provided a new basis for exploring the relevant pathogenesis.

Coronary Disease↗