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Biomedical subjects

J Ni

Publications and source records attributed to J Ni.

At least 73 records · Page 4Linked to original sources
PubMed2000

Study on open tubular capillary affinity liquid chromatography.

A novel mode of affinity chromatography (AC) based on an open tubular capillary column (OTAC) is demonstrated. The OTAC column is prepared by immobilizing Cibacron blue F3GA onto the inner surface of a 50-microm-i.d. capillary column. The AC experiment is performed on a capillary electrophoresis instrument by using its pressure system as the driving force. Bovine serum albumin and lysozyme (Lys) are successfully separated with stepwise gradient elution. The relative standard deviation (RSD) for the elution time of the retained Lys is 0.08%, and good repeatability of its peak area and peak height with an RSD value lower than 2.12% for 10 consecutive runs is observed. The loading capacity and detection limit for the retained Lys are approximately 36 ng and 8.6 ng, respectively. It is also found that the amount of protein adsorbed is unaffected by the flow rate of the loading buffer, and OTAC can be used for the fast determination of biopolymers. Some of the advantages of OTAC over conventional modes of open tubular capillary liquid chromatography are that the detection sensitivity and loading capacity of a sample can be greatly improved, because the relatively large inner diameter of the capillary can be adopted and the whole capillary column can be used to adsorb the solute in OTAC.

Journal Article↗
PubMed2000

Nicotine dependence and its familial aggregation in Chinese.

BACKGROUND: Nicotine dependence is a significant public health problem. This study attempted to characterize the prevalence and familial aggregation of nicotine dependence in China. METHODS: In 1998, we initiated a community-based cross-sectional study among residents of the Yuexi County in Anqing, China. A total of 991 current smokers from 488 randomly selected nuclear families were recruited and surveyed by use of the standardized Fagerstrom Test of Nicotine Dependence (FTND) questionnaire and the Revised Tolerance Questionnaire (RTQ). All study subjects were offspring in their respective nuclear families, and 478 male-male pairs (aged 41.7 +/- 12.1 years) were finally used for data analyses, because the number of female current smokers (n = 5) was too small. RESULTS: The correlation coefficient of the FTND and the RTQ scores was as high as 0.84 (P < 0.0001). Nicotine dependence, defined as an FTND score > or =8 or an RTQ score > or =28, had a prevalence of 12.7% and 11.1%, respectively. The respective sibling recurrent risk was 1.7 and 2.4, according to the FTND or the RTQ criteria. The adjusted odds ratios and 95% CI of nicotine dependence of second siblings in families in which the first sibling was nicotine dependent were 2.13 (95% CI: 1.02-4.43) and 3.50 (95% CI: 1.65-7.36) respectively, according to the FTND and RTQ criteria. CONCLUSIONS: The prevalence of nicotine dependence in male current smokers in China was comparable to that reported in previous US and European studies. Our findings suggest that genetic influences may play an important role in vulnerability to nicotine addiction.

Adult↗
PubMed2000

Metabolic gene polymorphisms and risk of dysmenorrhea.

We conducted a molecular epidemiologic study in rural China to investigate the association of the cytochrome P450 2D6 (CYP2D6) and glutathione S-transferase Mu (GSTM1) polymorphisms with dysmenorrhea. This report includes 435 subjects, 129 with and 306 without any history of dysmenorrhea, who did not smoke or drink alcohol. We obtained information on dysmenorrhea and major covariates by questionnaire interview. We used categorical methods and logistic regression models to evaluate the individual and combined associations of CYP2D6 and GSTM1 polymorphisms with dysmenorrhea and its subgroups, occasional (N = 70) and recurrent (N = 59), with adjustment for age, education, occupation, passive smoke exposure, age of menarche, parity, contraceptive method, height, and body mass index. Both variant CYP2D6 and GSTM1 genotypes were associated with increased risk of recurrent dysmenorrhea [for CYP2D6, odds ratio (OR) = 1.7 and 95% confidence interval (95% CI) = 0.9-3.1; for GSTM1, OR = 1.8 and 95% CI = 1.0-3.4). There was no appreciable association between these variant genotypes and occasional dysmenorrhea. When both the CYP2D6 and GSTM1 genotypes were considered together, the highest risk of recurrent dysmenorrhea was found among women with variant genotypes in both CYP2D6 and GSTM1 (OR = 3.1; 95% CI = 1.2-8.0). This study provides evidence of genetic susceptibility to recurrent dysmenorrhea.

Adult↗
PubMed2000

The L6 membrane proteins--a new four-transmembrane superfamily.

L6, IL-TMP, and TM4SF5 are cell surface proteins predicted to have four transmembrane domains. Previous sequence analysis led to their assignment as members of the tetraspanin superfamily. In this paper, we identify a new sequence (L6D) that is strikingly similar to L6, IL-TMP, and TM4SF5. Analyses of these four sequences indicate that they are not significantly related to genuine tetraspanins, but instead constitute their own L6 superfamily.

Amino Acid Motifs↗
PubMed2000

All human genes of the uteroglobin family are localized on chromosome 11q12.2 and form a dense cluster.

Rabbit uteroglobin is the founder member of a family of mammalian proteins that has expanded to more than 20 members within the last few years. All members are small, secretory, rarely glycosylated dimeric proteins with unclear physiological functions and are mainly expressed in mucosal tissues. A phylogenetic analysis shows that the family can be grouped into five subfamilies, A to E. Subfamily A contains rabbit uteroglobin and its orthologues from various species; most of these have been described to form antiparallel homodimers via two intermolecular disulfide bonds. All other subfamily members contain a third conserved cysteine and, from existing biochemical data, it can be predicted that a member of subfamily B or C will likely form heterodimers with a partner from subfamily E or D, respectively. Besides the mentioned cysteines, only one central lysine is conserved in all family members. In the known uteroglobin structures, this lysine forms an exposed salt bridge with an aspartate side chain, which is conserved in almost all sequences. Using radiation hybrid mapping and P1 clone analysis and utilizing data from the human genome project, we show that all known five human family members (Clara cell 10-kDa protein, lipophilins A and B, lacryglobin, mammaglobin) and a new member, we call lymphoglobin, are localized on chromosome 11q12.2 in a dense cluster spanning not more than approximately 400 kbp.

Amino Acid Sequence↗
PubMed2000

Detection of microorganisms in the tracheal aspirates of preterm infants by polymerase chain reaction: association of adenovirus infection with bronchopulmonary dysplasia.

Bronchopulmonary dysplasia (BPD) is recognized as an important cause of morbidity and mortality in preterm infants. Because the role of congenital infections in BPD has been debated, the purpose of this study was to test the hypothesis that detection of infectious agents in tracheal aspirate samples was associated with the development of BPD. Tracheal aspirate samples were obtained within the 1st week of life and screened by polymerase chain reaction for adenovirus, cytomegalovirus, parvovirus, enteroviruses, Ureaplasma urealyticum, Mycoplasma hominis, Mycoplasma pneumoniae, and Chlamydia species. BPD was defined as persistent oxygen dependence at 28 d of age and 36 wk postconceptional age (PCA). Infants that expired before these time points were excluded from statistical analysis. Out of 89 infants studied, at 28 d of life, 13 had expired, 45 had BPD, and 31 had no BPD (controls). At 36 wk PCA, 15 infants expired, 39 still had BPD, and 35 did not. A significant increase in the frequency of adenovirus genome was identified in BPD patients compared with controls, both at 28 d of life (12/45 = 27% versus 1/31 = 3%: p< or =0.01) and at 36 wk PCA (10/39 = 29% versus 2/35 = 6%: p = 0.01). Other microorganisms were rarely detected and not associated with the development of BPD. This is the first study reporting the frequency of detection of adenovirus DNA in tracheal aspirate samples obtained during the 1st week of life from infants with BPD and suggests that prenatal acquisition may be important in the development of BPD.

Adenoviridae↗
PubMed2000

Analysis of bioactive components in traditional Chinese medicines by molecular biochromatography with alpha1-acid glycoprotein stationary phase.

Molecular biochromatography with alpha1-acid glycoprotein (AGP) stationary phase was proposed to screen and analyse the biologically active components in traditional Chinese medicines (TCMs) with extracts from Radix Salviae miltiorrhizae as a tested sample. More than ten peaks were resolved based on their affinity to AGP. The effects of concentrations of acetonitrile, pH, concentration of inorganic salt and temperature on the retention behaviors of several major active components were also investigated, and it was found that the hydrophobic effect is the major contributor to retention. Tanshinone IIA was identified as one of the principal bioactive components, which is the marker for the quality control of Radix Salviae miltiorrhizae and a complicated remedy named YiXiTongMai. The amount of tanshinone IIA in Radix Salviae miltiorrhizae and YiXiTongMai determined by this method was 2.9 mg/g (net weight, RSD 4.9%, n=5) and 0.078 mg/g (net weight, RSD 2.5%, n=3), respectively. The possibility for fast differentiation of the TCM sources was also studied by the comparison of the fingerprint of chromatograms for eight typical TCMs on the AGP column. It was observed that different TCMs showed different fingerprint characteristics. Even for the same plant, Rhizoma cimicifugae from three different geographical sources, although there were common characteristics, distinct differences in types and concentrations of biologically active components were clearly observed. It was shown that molecular biochromatography was an effective and fast way for the analysis and screening of biologically active compounds in traditional Chinese medicines.

Abietanes↗
PubMed2000

Effect of endothelin-1 on the biological changes of the corpus luteum regression process.

The present study was conducted to evaluate whether apoptosis occurs during the corpus luteum (CL) regression process in rats, and, if so, to determine the effect of endothelin-1 (ET-1) in this process. In order to obtain CL cells, immature female rats were treated with pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG) to cause hyperovulation. CL cells were treated with three different dosages of ET-1 (1.0 x 10(-5) M, 1.0 x 10(-7) M, and 1.0 x 10(-9) M). The occurrence of apoptosis, intracellular calcium concentrations, and progesterone production were measured to determine the biological changes in the CL cells. We found that apoptosis occurs during CL regression accompanied by an increase in intracellular calcium, while progesterone production was decreased. ET-1 promotes the apoptosis through an increase in the intracellular calcium in the CL cells and affects the physiological function of CL cells by inhibiting progesterone production. ET-1 was shown to be an important regulator of CL during its regression.

Animals↗
PubMed2000

Fatal intrauterine adenoviral endomyocarditis with aortic and pulmonary valve stenosis: diagnosis by polymerase chain reaction.

We report a case of fatal hydrops fetalis owing to adenoviral endomyocarditis with aortic and pulmonary valve stenosis. A 1850-g macerated male stillborn delivered 1 week after fetal ultrasonography showed hydrops, cardiomegaly, and possible aortic valve stenosis. Autopsy confirmed hydrops and showed thickened, fibrotic semilunar valves with stenosis. The myocardium was focally fibrotic with areas of calcification. Polymerase chain reaction study of myocardial and aortic valve tissue was positive for adenovirus. Intrauterine viral myocarditis has been reported only rarely, but cases owing to Coxsackie B virus, adenovirus, and parvovirus B19 have appeared in the literature. With the exception of rubella, viral causation of significant valvular lesions in humans has received scanty support in the literature. This report suggests a broader group of causative agents. HUM PATHOL 31:1433-1435.

Adenoviridae Infections↗
PubMed2000

Changes in soluble interleukin-2 receptor level in serum and Na+-K+-exchanging ATPase activity in semen of infertile men caused by antisperm antibody.

AIM: To explore the possible mechanisms of male infertility caused by antisperm antibody (AsAb). METHODS: The soluble interleukin-2 receptor (sIL-2R) level in serum was analyzed by ELISA and Na+-K+-exchanging ATPase activity in semen by phosphorus (Pi) assay. RESULTS: The sIL-2R level in serum was significantly higher and the Na+K+-exchanging ATPase activity in semen significantly lower in AsAb positive infertile men when compared with the controls. CONCLUSION: The AsAb titer varies with the sIL-2R level in serum. A decrease in Na+-K+-exchanging ATPase activity in semen may play a role in male infertility caused by AsAb.

Adult↗
PubMed2000

[BIOME 6000 Project: latest advances of reconstructing palaeobiome].

Global change research needs the data about the past states of the Earth system, e.g., the pollen and plant macrofossil records for specified time slices (for example, the mid-Holocene interval, ca 6,000 aBP, and the last glacial maximun, LGM, ca 18,000 aBP). In the past, the utilization of these palaeoecological data is mostly scattered and point-fixed, and the reconstruction of palaeovegetation is often qualitatively descriptive. The establishment of international collaboration project BIOME 6000 (a global palaeovegetation mapping program) of the International Geosphere-Biosphere Project (IGBP) breaks a new approach for the synthesis and quantitative study of palaeoecological data. In the projescts The methodology of biomization for assigning palaeoeclogical records to biomes is emphasized, in which, plant pollen taxa are assigned to one or more plant functional types (PFTs) by collecting widely global palaeoecological records which have quality assurance, and by using PFT definition based on the principles of modern ecology. Through combining PFTs into biome types, the global synthesis of biomes reconstructed by using palaeoecological data can be realized. The biomization method might provide a benchmark for coupled atmosphere-biosphere. This trend will facilitate biome mapping for other time slices, and co-evolution of atmosphere-biosphere modeling and palaeodata synthesis and analysis will continue.

Ecology↗
PubMed2000

Oxidized low density lipoprotein inhibited tissue factor pathway inhibitor mRNA expression in human endothelial cells.

OBJECTIVE: To understand the role of oxidized low density lipoprotein (OX-LDL) in the pathogenesis of thrombotic complications in atherogenesis. METHODS: Low density lipoprotein was isolated from normal heparinized blood by density gradient ultracentrifugation and oxidized by CuCl2. Total RNA was extracted from human umbilical vein endothelial cells (HUVECs) exposed to LDL or OX-LDL, using the guanidinium isothiocyanate method. The quantification of tissue factor pathway inhibitor (TFPI) mRNA in HUVECs was carried out by reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: HUVECs were able to express TFPI mRNA constitutively. The expression was not affected by LDL but was effectively inhibited by OX-LDL in a time- and dose-dependent manner. CONCLUSIONS: The results suggest that oxidized LDL may play an important role in inducing coagulation in atherosclerotic lesions by the inhibition of expression of TFPI in vascular endothelial cells.

Endothelium, Vascular↗
PubMed2000

[Experimental study on effect of antagonizing platelet-activating factor and histamine of synthetic ginkgolide F in guinea-pigs].

OBJECTIVE: To investigate the antagonizing effect of synthetic Ginkgolide F (SGF) on platelet-activating factor (PAF) and histamine (HA) in guinea-pigs. METHODS: The contraction rate of isolated lung tissue of guinea-pig and the change of pulmonary function of sensitized guinea-pig after SGF treatment were examined. RESULTS: (1) The contraction rate of guinea-pigs' isolated trachea and lung strip induced by HA reduced from (50.97 +/- 16.00)% and (54.24 +/- 12.17)% to (21.69 +/- 3.85)% and (22.97 +/- 17.78)% after SGF treatment (P < 0.05). (2) PAF induced relative contraction of isolated guinea-pig lung strip was reduced from (89.49 +/- 16.00)% to (46.21 +/- 14.23)% in presence of SGF (P < 0.05). (3) The pulmonary function of sensitized animal had a tendency of being improved by SGF. CONCLUSION: SGF can antagonize the contraction of isolated lung tissue induced by HA or PAF in vitro, and has a tendency to improve the pulmonary function of sensitized guinea-pig, therefore, it may be a promising drug in treatment of bronchial asthma.

Animals↗
PubMed2000

[Effect of intravascular laser irradiation of blood and traditional Chinese medical therapy on immune function in senile cerebral infarction patients of kidney deficiency type].

OBJECTIVE: To observe the effect of intravascular laser irradiation of blood (ILIB) therapy on cellular immunity, change of T-lymphocyte subsets and humoral immunity in senile cerebral infarction patients of Kidney deficiency type. METHODS: Seventy-five patients were divided randomly into the ILIB group and the control group treated by conventional medicine (CM). Serum CD3, CD4, CD8, IgG, IgA, IgM, C3 and C4 levels of patients were determined before and after treatment for self-control and comparing between various groups and that of normal control. RESULTS: Before treatment, in patients of both groups, the levels of CD3, CD4, CD4/CD8, C3 were all lower than normal levels significantly, C4 and IgM higher than normal (P < 0.05, P < 0.01), the level of IgG lowered in patients inclined to Kidney-Yang deficiency and raised in those inclined to Kidney-Yin deficiency (P < 0.01). After treatment, in the ILIB group, CD3, CD4 and CD4/CD8 raised significantly (P < 0.05, P < 0.01), IgG and C3 varied towards normal control (P < 0.01, P < 0.05), and C4 lowered but without significance. In the control group, the indexes changed also toward normal but without significance except the change of IgG (P < 0.05). As for IgA and IgM, marked changes were not found in both groups in comparison between before and after treatment. CONCLUSION: ILIB therapy could bi-directionally regulate cellular and humoral immunity in senile cerebral infarction patients of Kidney deficiency type, which was similar to the function in supplementing Qi and invigorating Kidney of Chinese herbal medicine.

Aged↗
PubMed2000

[GABA inhibits progesterone production of luteal cells of rat ovary].

In the present work we report that GABA inhibits progesterone production and increases the amount of hydroxyl radical in cultured rat luteal cells. The inhibitory effect of GABA on progesterone production may be mediated by adenylate cyclase system and GABA(A) receptor, but not through protein synthesis pathway.

Adenylyl Cyclases↗
PubMed2000

[Determination of ultra-trace rare-earth elements in human plasma by inductively coupled plasma mass spectrometry].

Inductively coupled plasma mass spectrometry (ICP-MS), highly sensitive inorgnic analytic technique, fits to determine ultra-trace rare-earth elements in human plasma. Under the optimized conditions detection limits for 15 rare-earth elements are in the range of 0.7 (for Eu)-5.4 (for Gd) ng.L-1. Indium as an internal standard element is used to compensate for matrix suppression effect and sensitivity drift. Three kinds of preparation methods, diluted with 1% HNO3, digested with HNO3-H2O2 and with HNO3-HClO4, are checked and compared, and the former is the simplest way to be measured. The samples diluted with 1% HNO3, stored in 4 degrees C, are very steady for 16 days. With the method, 11 healthy plasma samples in Changchun area of China are analysed.

Europium↗
PubMed1999

Identification and characterization of a novel siglec, siglec-7, expressed by human natural killer cells and monocytes.

We describe the characterization of sialic acid-binding Ig-like lectin-7 (siglec-7), a novel member of the siglec subgroup of the immunoglobulin superfamily. A full-length cDNA encoding siglec-7 was isolated from a human primary dendritic cell cDNA library. Siglec-7 is predicted to contain three extracellular immunoglobulin-like domains that comprise an N-terminal V-set domain and two C2-set domains, a transmembrane region and a cytoplasmic tail containing two tyrosine residues embodied in immunoreceptor tyrosine-based inhibition motif-like motifs. Overall, siglec-7 exhibited a high degree of sequence similarity to genes encoding CD33 (siglec-3), siglec-5, OBBP1/siglec-6, and OBBP-like protein and mapped to the same region on chromosome 19q13.3. When siglec-7 was expressed on COS or Chinese hamster ovary cells, it was able to mediate high levels of sialic acid-dependent binding to human erythrocytes and soluble sialoglycoconjugates, suggesting that it may be involved in cell-cell interactions. Among human peripheral blood leukocytes, siglec-7 was found to be present at low levels on granulocytes, intermediate levels on monocytes, and relatively high levels on a major subset of natural killer cells and a minor subset of CD8(+) T cells. Immunoprecipitation experiments indicated that siglec-7 is expressed as a monomer of approximately 65 kDa.

3T3 Cells↗