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Biomedical subjects

G Y Li

Publications and source records attributed to G Y Li.

At least 19 recordsLinked to original sources
PubMed2006

Association between the scores on the general health questionnaire-28 and the saliva levels of 3-methoxy-4-hydroxyphenylglycol in normal volunteers.

To access the saliva level of 3-methoxy-4-hydroxy-phenylglycol (sMHPG) as an index of mental health in normal volunteers, we investigated the relationship between the sMHPG and the scores on the general health questionnaire-28 (GHQ-28). A total of 270 normal volunteers answered the GHQ-28 and the sMHPG levels were determined. The sMHPG levels in women and men were comparable. There was a significant negative correlation between the social dysfunction score on the GHQ-28 and sMHPG levels in women (P=0.0035), but not in men. Moreover, the sMHPG levels also correlated with the total GHQ-28 score (P=0.0205), the anxiety and the insomnia score (P=0.0306) in women. These data indicate a high social dysfunction score on the GHQ-28 to be associated with a reduced noradrenergic neuronal tone thus possibly reflecting psychomotor retardation in women.

Adult↗
PubMed2004

Involvement of the noradrenergic system in performance on a continuous task requiring effortful attention.

To determine the effects of noradrenergic neuronal activity on performance in continuous tasks requiring effortful attention, the performance of 23 male students in the Uchida-Kraepelin test (UKT) was examined. The UKT requires continuous arithmetic addition of single-digit figures for 25 min. The relationship of performance with saliva levels of 3-methoxy-4-hydroxyphenylglycol (sMHPG) was analyzed. Saliva samples were taken before, during and after test performance, and sMHPG levels determined by gas chromatography-mass spectrometry. There was no significant change in mean sMHPG as a result of test performance. However, when initial effort was calculated, defined as number of items completed during the 1st min subtracted from the average completed per minute in the 1st and the 2nd halves (blocks) of the test, significant correlations with sMHPG (p = 0.0002 for the 1st block and p < 0.0001 for the 2nd block) were found. Thus the data indicate that noradrenergic neuronal activity affects the performance on continuous tasks requiring effortful attention.

Adult↗
PubMed2001

[Study on the fusion expression of FBXO30: a novel member of F-box protein family].

OBJECTIVE: The cDNA sequence of the coding region of FBXO30 (F-box only protein 30), which is a novel member of F-box protein family, was cloned into the mammalian expression vector pEGFP-C2 by non-directional cloning method and introduced into the NIH 3T3 cells by liposome transfection. Observation under the fluorescent microscopy after transfection showed that EGFP (enhanced green fluorescent protein)/FBXO30 was expressed and existed mainly in the cytoplasm. At the same time, the cDNA sequence of the coding region of FBXO30 was cloned into prokaryotic expression vector pGEX-4T-2 by directional cloning strategy. The GST (glutathione S-transferase)/FBXO30 fusion protein was expressed under the induction of IPTG (isopropylthio-beta-D-galactoside) in E. coli. A new band (approximately 65.5 kD) was detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting. Purification of the GST-fused FBXO30 was carried out by affinity chromatography with glutathione sepharose 4B. The fusion expression of FBXO30 indicates that: FBXO30 protein is a cytoplasmic soluble protein, and the stable fusion expression of FBXO30 in the prokaryotic expression system can provide a base for the preparation of the specific antibody of FBXO30 and further functional study of FBXO30.

3T3 Cells↗
PubMed2001

The mRNA level of the potassium-chloride cotransporter KCC2 covaries with seizure susceptibility in inferior colliculus of the post-ischemic audiogenic seizure-prone rat.

Cardiac arrest and resuscitation were used to induce brain damage and susceptibility to sound-triggered seizures in Sprague-Dawley rats. Glucose preloading was used to vary seizure susceptibility. Because loop diuretics can block these seizures, we investigated changes in KCC2, a potassium-chloride cotransporter, in the inferior colliculus - the origin of the seizures. Using polymerase chain reaction (PCR), we found that collicular KCC2 mRNA levels covaried with seizure susceptibility in these animals. Using quantitative PCR, we found that a fivefold increase in collicular KCC2 mRNA levels was associated with a doubling of seizure incidence. A hypothesis linking KCC2 activity to seizure susceptibility is presented.

Animals↗
PubMed1999

[A nasopharyngeal carcinoma negatively related EST on 7q32].

To isolate and clone the tumor suppressor gene on chromosomal region 7q32 that corelated with the occurrence of human NPC, we detected the genotype of polymorphic microsatellite markers on 7q32 in 24 nasopharyngeal carcinoma biopsies and matched normal lymphocyte DNA. LOH was found in 30% biopsies. Using differential RT-PCR and Northern hybridization we compared the expression level of 20 EST on 7q32 between NPC cell line HNE1 and primary culture of normal nasopharyngeal epithelial cell, and found AA070437 EST expressed high in primary culture of normal nasopharyngeal epithelial cell, but very low in HNE1. Differential RT-PCR (dRT-PCR) analysis showed that the expression level of AA070437 was lower in 30.7% NPC biopses than in normal cell. Differential PCR (dPCR) showed that allelic loss of AA070437 was observed in 29.1% NPC biopses. This EST is a part of sequence of a new gene compared with GeneBank database. Our results showed that AA070437 EST negatively related with the occurrence of human NPC is a candidate of tumor suppressor gene of NPC on 7q32.

Base Sequence↗
PubMed1999

[Simultaneous observation of parameter of intraventricular pressure and energy metabolism in rat hearts using nuclear magnetic resonance].

A technique for simultaneous observation of parameters of intraventricular pressure and energy metabolic status in isovolumic rat hearts was described. The parameters of intraventricular pressure were collected and processed using a computerized monitoring system for heart function, and myocardial energy metabolism was investigated by collecting the 31P NMR spectra. The preparation was stable metabolically and functionally for 2 h under the NMR experimental conditions.

Animals↗
PubMed1998

Gap junction Cx26 gene modulation by phorbol esters in benign and malignant human mammary cells.

Connexin (Cx) 26, a major gap junction protein expressed in mammary epithelial cells, has been considered to be a tumor suppressor gene candidate. This study investigated the molecular mechanism of transcriptional up-regulation of Cx26 by phorbol ester (TPA) in human immortalized MCF-10 mammary epithelial cells and MDA-MB-231 mammary cancer cells. Such up-regulation was mediated through the protein kinase C pathway and could be blocked by the PKC inhibitor, calphostin C. Based on the results of the nuclear run-on assay, there was a TPA-induced increase in the rate of transcriptional initiation. We identified a TPA-induced DNase I hypersensitivity (DH) region approximately 1 kb 5' upstream of the ATG translation starting site. Sequence analysis revealed that this DH region was located in intron 1 and contained two TRE-like TGAT/ATCA elements, two 5'TTCA3' motifs and a 5'AGGAAG3' PEA3 motif. Both TRE-like elements were capable of binding AP1. TPA inducibility of this DH region was seen by the CAT reporter assay and appeared to be direction-dependent suggesting a functional cooperation between PEA3/TTCA and TRE.

Base Sequence↗
PubMed1998

The novel function of the Saccharomyces cerevisiae CBP2 gene as a splicing factor essential to excision of the Saccharomyces douglasii LSU intron in vivo.

In the yeast Saccharomyces cerevisiae, the product of the nuclear gene CBP2 is required exclusively for the splicing of the terminal intron of the mitochondrial cytochrome b gene. The homologous gene from the related yeast, Saccharomyces douglasii, has been shown to be essential for respiratory growth in the presence of a wild-type S. douglasii mitochondrial genome and dispensable in the presence of an intronless mitochondrial genome. The two CBP2 genes are functionally interchangeable although the target intron of the S. cerevisiae CBP2 gene is absent from the S. douglasii mitochondrial genome. To determine the function of the CBP2 gene in S. douglasii mitochondrial pre-RNA processing we have constructed and analyzed interspecific hybrid strains between the nuclear genome of S. cerevisiae carrying an inactive CBP2 gene and S. douglasii mitochondrial genomes with different intron contents. We have demonstrated that inactivation of the S. cerevisiae CBP2 gene affects the maturation of the S. douglasii LSU pre-RNA, leading to a respiratory-deficient phenotype in the hybrid strains. We have shown that the CBP2 gene is essential for excision of the S. douglasii LSU intron in vivo and that the gene is dispensable when this intron is deleted or replaced by the S. cerevisiae LSU intron.

Cell Division↗
PubMed1997

[Relationship between syndrome differentiation-typing and expression of platelet-activation molecule CD62P and CD63 on platelets in psoriatic patients].

OBJECTIVE: To understand the relationship between Syndrome Differentiation- Typing and platelet activation in psoriatic patients. METHODS: Expression of platelet-activation molecules CD62P (alpha-granule membrane glycoprotein) and CD63 (lysosomal integral membrane protein) on platelets from 36 psoriatic patients with Syndrome Differentiation-Typing in TCM and 31 health subjects were investigated by using flow cytometry and specific monoclonal antibodies against activated platelet. RESULTS: (1) Increased expression of CD62P and CD63 on platelets from psoriatic patients was observed (P < 0.001); (2) The expression of CD62P and CD63 was in following order: The group of Blood Stasis > Blood Dryness > Blood Heat; (3) Compared with the group of Blood Heat, increased expression of CD62P and CD63 was observed in the group of Blood Dryness (P < 0.001); (4) Compared with the group of Blood Dryness, increased expression of CD62P and CD63 was observed in the group of Blood Stasis (P < 0.001). CONCLUSION: The platelet activation might play an important role in higher blood viscosity, endothelial cell injury, abnormal microcirculation, which was correlated with Blood Stasis, found in psoriasis.

Adolescent↗
PubMed1997

[Chemical investigation of genus Hedyotis. II. Isolation and identification of iridoids from Hedyotis chrysotricha].

Many species of genus Hedyotis (Rubiaceae) were used as folk medicine for treatment of cold, inflammation, cancer and etc. in China. The alcoholic extract of the whole plant of H. chrysotricha showed good hepatoprotective effects. From the alcoholic extract ten iridoids were isolated and their structures were elucidated as: asperuloside (1), scandoside methyl ester (2), asperulosidic acid (3), deacetyl asperulosidic acid (4), loganin (5), deacetyl asperuloside (6), acetyl scandoside methyl ester (7), 6 beta-hydroxy-genipin (8) and two new compounds named hedyoside (9) and 6'-acetylasperuloside (10), by means of chemical and spectral methods.

Drugs, Chinese Herbal↗
PubMed1997

[Smoking behaviour and its influencing factors among cigarette smokers in Beijing].

An investigation was carried out among 6,000 persons aged 15-70 to explore the prevalence of cigarette smoking and its risk factors in urban and suburban areas of Beijing. Results showed that 39.07% of Beijing residents were smokers (58.95% male, 17.42% female) who started smoking at an average age of 19.52% and over 2/3 of them admitted their initiafion of smoking was mainly due to curiosity and pressure from social intercourse. Results of polychotomas regression analysis demonstrated that the risk factors of smoking were related to sex, poor education, unhappy marriage, and lacking of knowledge on the negative health outcome of smoking. It is suggested that the program on smoking of control should be strengthened in Beijing.

Adolescent↗
PubMed1996

In vitro mutagenesis of the mitochondrial leucyl tRNA synthetase of Saccharomyces cerevisiae shows that the suppressor activity of the mutant proteins is related to the splicing function of the wild-type protein.

The NAM2 gene of Saccharomyces cerevisiae encodes the mitochondrial leucyl tRNA synthetase (mLRS), which is necessary for the excision of the fourth intron of the mitochondrial cytb gene (bI4) and the fourth intron of the mitochondrial coxI gene (aI4), as well as for mitochondrial protein synthesis. Some dominant mutant alleles of the gene are able to suppress mutations that inactivate the bI4 maturase, which is essential for the excision of the introns aI4 and bI4. Here we report mutagenesis studies which focus on the splicing and suppressor functions of the protein. Small deletions in the C-terminal region of the protein preferentially reduce the splicing, but not the synthetase activity; and all the C-terminal deletions tested abolish the suppressor activity. Mutations which increase the volume of the residue at position 240 in the wild-type mLRS without introducing a charge, lead to a suppressor activity. The mutant 238C, which is located in the suppressor region, has a reduced synthetase activity and no detectable splicing activity. These data show that the splicing and suppressor functions are linked and that the suppressor activity of the mutant alleles results from a modification of the wild-type splicing activity.

Endoribonucleases↗
PubMed1996

The CBP2 gene from Saccharomyces douglasii is a functional homologue of the Saccharomyces cerevisiae gene and is essential for respiratory growth in the presence of a wild-type (intron-containing) mitochondrial genome.

In Saccharomyces cerevisiae the only known role of the CBP2 gene is the excision of the fifth intron of the mitochondrial cyt b gene (bI5). We have cloned the CBP2 gene from Saccharomyces douglasii (a close relative of S. cerevisiae). A comparison of the S. douglasii and S. cerevisiae sequences shows that there are 14% nucleotide substitutions in the coding region, with transitions being three times more frequent than transversions. At the protein level sequence identity is 87%. We have demonstrated that the S. douglasii CBP2 gene is essential for respiratory growth in the presence of a wild-type S. douglasii mitochondrial genome, but not in the presence of an intronless S. cerevisiae mitochondrial genome. Also the S. douglasii and S. cerevisiae CBP2 genes are completely interchangeable, even though the intron bI5 is absent from the S. douglasii mitochondrial genome.

Amino Acid Sequence↗
PubMed1996

[Influence of different combination of mental activity and respiratory cycle on heart rate variability].

By means of spectral analysis of P-R interval, different characteristics of heart rate variability in different form of respiratory exercise was observed. The results of observation on 32 volunteers showed that mental activity that affected respiration can influence the function of autonomic nerve system in a different way. When the mind was concentrated at the inspiration, the function of autonomic nerve system was kept in balance, and both the sympathetic and the vagal activities enhanced significantly and while mind concentrated at the expiration could induce a reduction of vagal activity so as to produce marked change in the sympathovagal balance.

Breathing Exercises↗
PubMed1995

Application of dot-immunogold-silver staining in the diagnosis of clonorchiasis.

All 35 confirmed clonorchiasis cases showed a positive reaction in dot-immunogold-silver staining (Dot-IGSS) with a mean serum titre of 1:1656, while none of the sera from 35 normal individuals reacted. A seroepidemiological survey of middle-school students revealed a positive rate of 17.0% (142/836), and 76.1% (105/138) of the serologically positive students were egg positive in stool examination. The egg positive rates in those with antibody at levels of 1+ to 4+ were 57.1% (28/49), 75.7% (28/37), 94.7% (36/38) and 92.9% (13/14) respectively. It is believed that Dot-IGSS can be used for the clinical diagnosis and epidemiological survey of clonorchiasis.

China↗
PubMed1994

Simultaneous occurrence of fumonisin B1 and other mycotoxins in moldy corn collected from the People's Republic of China in regions with high incidences of esophageal cancer.

A total of 31 corn samples collected from households in the counties of Cixian and Linxian of the People's Republic of China, where high incidences of esophageal cancer have been reported, were analyzed for fumonisin B1 (FB1), aflatoxin, and total trichothecene mycotoxins. High levels of FB1 (18 to 155 ppm; mean, 74 ppm) were found in 16 of the samples that showed heavy mold contamination. FB1, at lower levels (20 to 60 ppm; mean, 35.3 ppm), was also found in 15 samples, collected from the same households, that did not show any visible mold contamination. The levels of aflatoxin in the samples were low (1 to 38.4 ppb; mean, 8.61 ppb). High levels of total type-A trichothecenes were also found in the moldy corn samples (139 to 2,030 ppb; mean, 627 ppb). Immunochromatography of selected samples revealed that these samples contained T-2 toxin, HT-2 toxin, iso-neosolaniol, monoacetoxyscirpenol, and several other type-A trichothecenes. The concentration of total type-B trichothecenes in 15 moldy corn samples was in the range of 470 to 5,826 ppb (mean, 2,359 ppb). High levels (3.7 to 5.0 mg/g) of FB1 were produced in corn in the laboratory by five Fusarium moniliforme strains isolated from the moldy corn. These fungi were also capable of forming various nitrosamines (5 to 16 micrograms per flask) in the presence of nitrate and precursor amines.(ABSTRACT TRUNCATED AT 250 WORDS)

China↗