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Biomedical subjects

J Q Li

Publications and source records attributed to J Q Li.

At least 19 recordsLinked to original sources
PubMed2003

pp60c-src activation in lung adenocarcinoma.

Nine src family members are known including c-Src, c-Yes, c-Lck, c-Fyn, c-Hck, c-Lyn, c-Blk, c-Fgr and c-Yrk. They encode proteins with molecular weights of 55-62 kilodaltons (kDa), which are either cytoplasmic or membrane-associated protein tyrosine kinases. A close correlation exists between an elevated pp60c-src tyrosine kinase activity and cell transformation. However, the level of activation of pp60c-src in non-small cell lung cancers (NSCLC) remains obscure. The aim of this study was to examine the level of activity of pp60c-src in NSCLC. pp60c-src expression and in vitro protein tyrosine kinase activity in lung cancer tissue samples were measured by western blotting and in vitro kinase assays and compared with those in the surrounding non-tumour lung tissue from the same patient. pp60c-src phosphorylation was assessed by two-dimensional tryptic phosphopeptide mapping. The kinase activity of pp60c-src was significantly activated in NSCLC, especially in adenocarcinomas. In addition, the pp60c-src kinase activity increased with the size of the adenocarcinoma. Two-dimensional tryptic phosphopeptide mapping showed dephosphorylation of pp60c-src at Tyr 530 in adenocarcinomas. The proto-oncogene product, pp60c-src, was activated in NSCLC, especially in adenocarcinomas, in part through the dephosphorylation of Tyr 530. Our results suggest that activation of pp60c-src might play an important role in the progression of lung adenocarcinomas.

Adenocarcinoma↗
PubMed2002

Newcastle disease outbreaks in western China were caused by the genotypes VIIa and VIII.

Twelve Newcastle disease virus (NDV) strains were isolated from chickens involved in outbreaks of Newcastle disease (ND) in western China (Shaanxi, Gansu, Xinjiang, Qinghai and Guangxi provinces) between 1979 and 1999. All strains were determined to be velogenic by plaque formation, the mean death time (MDT) of embryonated eggs, and the intracerebral pathogenicity index (ICPI). For preparation of virus RNA, the acid guanidinium-thiocyanate method was used. A 908bp fragment of nucleotide was amplified by RT-PCR starting from the N terminal of the F gene and the PCR segments were cloned into the PGEM-T vector and sequenced. The similarities of the nucleotide sequences (1-519bp) and predicted amino acid sequences of the F gene (1-125) were analyzed by comparing the 12 NDV isolates with the NDV vaccine strains Lasota, B1, H1 and V4, with classical NDV strains and recent epizootic strains. Phylogenetic analysis demonstrated that all strains were of two novel genotypes; the NDV strains that caused the outbreak of ND in western China during 1998-1999 was of the genotype VIIa, whereas the strains from the Qinghai province (1979-1985) were of genotype VIII, which has been found predominately in southern Africa.

Amino Acid Sequence↗
PubMed2002

p107 Expression in colorectal tumours rises during carcinogenesis and falls during invasion.

p107 Links to cyclin A/CDK2 (cyclin-dependent kinase 2) and cyclin E/CDK2 that are important cell cycle regulators. However, p107 expression remains unclear in almost all kinds of human solid tumours. To clarify the expression of p107 in colorectal tumours, 22 normal mucosae, 9 hyperplastic polyps, 60 adenomas, 198 primary carcinomas, 21 lymph-nodal metastases, and 10 hepatic metastases were immunohistochemically stained for p107, cyclin A, cyclin E, CDK2 and Ki67. Results were measured using labelling indices (LIs). p107 LIs surpassed the highest value in normal tissues in six of nine hyperplastic polyps, 54 of 60 adenomas, 144 of 198 primary cancers, 13 of 21 nodal foci and three of 10 hepatic foci. p107 LIs also apparently rose from normal through hyperplasia and adenoma to early carcinoma. However, they declined in liver-metastatic foci, and in primary cancers showing large size, mucinous type, venous invasion, lymphatic invasion, poorly differentiated type, deep invasion, lymph-nodal metastasis, hepatic metastasis or advanced stage. Low p107 LIs were also linked to a poor survival, particularly in stage-III patients. As the p107 LI gradually rose, the CDK2 (in primary cancers only), cyclin A, cyclin E and Ki67 LIs were elevated concurrently-in both adenomas and primary cancers. Thus, in colorectal tumours, p107 expression rises abnormally and gradually during carcinogenesis and then falls during invasion, and thereby probably perturbs the cell-cycle control and promotes carcinogenesis and invasion. Clinically, reduced p107 may indicate a poorer prognosis.

Adult↗
PubMed2002

Neurochemical regulation of cough response to capsaicin in guinea-pigs.

1. Although monumental efforts have been made to define the action sites of cough, the importance of neurotransmitter systems in the cough reflex has received limited attention. We studied the roles for four major neurotransmitters [acetylcholine, histamine, serotonin (5-hydroxytryptamine, 5-HT) and dopamine] in the modulation of the cough reflex. 2. Atropine (muscarinic cholinergic blocking agent), pyrilamine maleate (PM, histamine H1 blocker), cimetidine (histamine H2 blocker), 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT, specific 5-HT1A receptor agonist) and SCH-23390 (selective dopamine D1 receptor antagonist) were examined on the cough response to inhaled capsaicin in conscious guinea-pigs. 3. All the drugs significantly decreased the number of capsaicin-induced coughs in a dose-dependent manner. To compare the sensitivity of these drugs on cough response, we calculated the effective doses for 50% inhibition of cough (ED50) when the animals were exposed to 3 x 10-4 m capsaicin. The ED50 values were 0.03 microm kg-1 for atropine, 0.2 microm kg-1 for 8-OH-DPAT, 6.2 microm kg-1 for SCH-23390, 8.5 microm kg-1 for PM and 13.9 microm kg-1 for cimetidine. 4. These findings indicated that all these four neurotransmitters may be involved in the regulation of the cough reflex. Multiple changes of these neurotransmitters in disorders of the central nervous system might synergically affect the cough reflex.

Animals↗
PubMed2001

Genome-wide analyses on loss of heterozygosity in hepatocellular carcinoma in Southern China.

BACKGROUND/AIMS: To conduct a genome-wide analysis of loss of heterozygosity (LOH) and its clinical significance in hepatocellular carcinoma (HCC) in Southern China where high incidence of HCC was documented. METHODS: LOH of 382 microsatellite loci on all autosomes were detected with polymerase chain reaction-based microsatellite polymorphism analyses in 104 HCC tumor tissues. RESULTS: High frequency of LOH (>55.7%) was observed on chromosome 1p, 1q, 2q, 3p, 4q, 6q, 8p, 9p, 13q, 16q, and 17p. LOH rates on loci D4S2964 (4q21.21), D8S277 (8p23.1-pter) and D17S938 (17p13.1-p13.3) were significantly higher in cases with positive HBsAg than in those with negative HBsAg. Similarly, LOH on loci D1S214 (lp36.3), D1S2797 (1p34) and D3S3681 (3p11.2-p14.2) were more frequently detected in tumors with intrahepatic metastasis than in those without. CONCLUSIONS: Status of LOH in HCC in Southern China is similar to that reported previously in other countries and areas. However, we firstly identified high-frequency LOH on chromosome 3p in HCC. Furthermore, HBV infection, as well as tumor intrahepatic metastasis, may be correlated with allelic losses on certain chromosome regions.

Adolescent↗
PubMed2001

Expression of cyclin E and cyclin-dependent kinase 2 correlates with metastasis and prognosis in colorectal carcinoma.

The expression of cyclin E and cyclin-dependent kinases 2 (CDK2) in metastatic foci, the relationship of their expression with some clinicopathologic characteristics, and the correlation of their expression with prognosis remain unclear. To examine the roles of their expression in the progression of colorectal carcinoma, 21 normal mucosa, 9 hyperplastic polyps, 58 adenomas, 17 adenocarcinoma in adenomas, 203 primary cancers, 21 lymph node metastases, and 10 hepatic metastases were immunohistochemically stained with anti-cyclin E, anti-CDK2, and anti-Ki67 antibodies. In the carcinogenic process, both cyclin E and CDK2 expressions increased significantly. From the primary to the lymph node-metastatic foci, cyclin E protein remained unchanged, but CDK2 increased significantly. From the primary to the liver-metastatic foci, cyclin E apparently decreased, and CDK2 was reduced almost to zero. In primary carcinomas, the reduction of cyclin E was significantly associated with large tumor size, mucinous type, venous invasion, deep infiltration, lymph nodal metastasis, peritoneal metastasis, advanced stage, and poor prognosis. Decreased CDK2 was obviously correlated with large tumor size, venous invasion, deep infiltration, hepatic metastasis, advanced stage, and poor prognosis. Increased cyclin E protein was related to elevated CDK2, which was further linked to higher Ki67. Thus, CDK2 overexpression could facilitate lymph node metastasis. The overexpression of cyclin E and CDK2 may mainly promote the progression of early cancer. Anti-cyclin E or anti-CDK2 chemotherapy should be targeted to the cancers with such overexpression.

Adenocarcinoma↗
PubMed2001

[Study on in vitro culture and cryopreservation by vitrification of blastocysts derived from single mouse 2-cell embryos' blastomeres].

The present experiments were designed to study the effects of glucose, EDTA, glutamine on the in vitro development of single blastomeres from 2-cell embryos in mouse, and the efficiency of cryopreservation of blastocysts from single blastomers with different vitrification. Single blastomeres derived from female ICR x male BDF1 2-cell embryos were cultured in mKRB with or without glucose, EDTA and glutamine, respectively. The expanded blastocyst rates were significantly different between in mKRB with glucose and without glucose (34% vs 65%); The blastomeres were cultured in mKRB with EDTA and glutamine but glucose, the expanded blastocyst rate (90%) was significantly higher than other groups. The blastocysts derived from single blastomeres were vitrified in liquid nitrogen after equilibration in GFS40 for 0.5-2 min, the survival rate 24%-51%. The blastocysts were pretreated in mPBS with 10% glycerol for 5 min, followed by exposure to GFS40 at 25 degrees C for 0.5 min, then vitrified in liquid nitrogen(two-step method), the survival rate was 61%. However, the survival rates increased to 64% and 70% when the blastocysts were vitrified(one-step method) ater equilibration in EFS40 at 25 degrees C for 0.5-1 min.

Animals↗
PubMed2001

[Automatic analyzing system for human chromosome].

A designing method for chromosome automatic analyzing system is presented in the paper. The system accomplishes chromosome automatic recognizing, sorting, pairing, picking out aberrant chromosomes and then makes diseases-diagnosis.

Algorithms↗
PubMed2001

[Determination of trace nickel in coal gangue by catalytic fading spectrophotometry].

In KH2PO4-Na2B4O7 (pH = 6.3) buffered solution the trace Ni(II) can strongly catalyze the fading reaction of carmine. Time and temperature can influence the reaction, and the reaction stops at the low temperature. Based on this study, a catalysis spectrophotometric method for determining trace Ni(II) is developed. The results show that the detection limits of the method is 2.5 x 10(-11) g.mL-1 for Ni(II) and Beer's law is obeyed for Ni(II) in the range of 0-1.2 micrograms.50 mL-1. Combined with solvent extraction spearation, the method has been applied to the determination of trace Ni in coal gangue with satisfactory results.

Carmine↗
PubMed2000

Serotonin reuptake is less efficient in taste aversion resistant than in taste aversion-prone rats.

We have previously reported the development of rat lines bred selectively for differences in taste aversion conditionability. Earlier studies demonstrated that the taste aversion resistant (TAR) animals exhibited lower concentrations of brain serotonin and consumed greater amounts of ethanol than their taste aversion prone (TAP) counterparts. In the present study, TAR rats demonstrated significantly less efficient brain serotonin transport compared to TAP rats, but the rat lines demonstrated similar levels of serotonin transporter or V(max) and similar whole brain paroxetine (a specific serotonin reuptake inhibitor) binding (B(max)). These results suggest that the rat lines differ in the mechanisms that transport serotonin into nerve endings, but do not differ in the binding of serotonin to the transporter or in the number of serotonin transport sites. The data support the hypothesis that genetically determined differences in the serotonin system contribute to individual differences in taste aversion conditionability. The findings further suggest that differences in serotonin transport may influence the propensity to self-administer ethanol.

Animals↗
PubMed2000

[Estimates of breeding value of Inner Mongolia cashmere goats using animal model BLUP method].

In this study, single trait animal model of best linear unbiased prediction (BLUP) procedures was used to obtain estimates of 3,981 Inner Mongolia cashmere goats' breeding value for body weight and cashmere yield. The data were collected during 1989-1998 at Arbas cashmere goats farm, Etuoke banner, Inner Mongolia. Multiple traits of BLUP were used to get estimates of total breeding values (TBV) of all goats. The model included age and sex-herd-year as fixed effects, and individual additive effect and individual permanent environment as random effects. The selection based on breeding value and phenotypic value was compared. The results showed as following: (1) There was a large difference between weaning weight selection and TBV selection of ram lamb; (2) The difference between phenotypic selection and TBV selection of gimmer hogg reached a significant level (P < 0.01); (3) The difference between phenotypic selection and TBV selection of ram hogg reached a significant level (P < 0.01); (4) Rank correlation between body weight selection and body weight' EBV selection and that between cashmere yield selection and cashmere yield' EBV selection were not significant (P > 0.05). The study concluded precision of individual phenotypic selection was low and animal model BLUP was suitable to select Inner Mongolia cashmere goats. At last, this study gave a series of methods of selecting sires based on objective reality.

Animals↗
PubMed2000

[Effects of hypotonic stress on the survival of hatched mouse blastocysts pericryopreservation].

The objective of this study to evaluate the effect of hypotonic stress on developmental potential of hatched blastocysts perivitrification. Hatched mouse blastocysts were vitrified in liquid nitrogen after equilibration in 10% or 20% GL for 5 min and in GFS40 for 30 sec respectively, the survival rates were 93%-97% after the frozen-thawed embryos were cultured in vitro for 24 h. There were no statistical difference between the frozen and the fresh group (P > 0.05). In order to evaluate effects of hypotonic stress on developmental abilities, fresh hatched mouse blastocysts were respectively exposed to 1.00 x, 0.50 x, 0.30 x, 0.25 x and 0.20 x PBS for 30 min, then cultured in mKRB for 24 h, the survival rates were 98%, 99%, 92%, 92% and 50% respectively. The rate in 0.20 X PBS group was significantly lower than in other groups (P < 0.01). When frozen-thawed embryos were directly treated with different osmotic solutions, the survival rates were 88%, 72%, 58%, 11% and 0 respectively in 1.00 x, 0.50 x, 0.30 x, 0.25 x and 0.20 x PBS group. The rate in 1.00 x PBS group was significantly higher than in other groups (P < 0.05). However, when frozen-thawed embryos were first cultured in vitro for 12 h, then exposed to 1.00 x, 0.50 x, 0.30 x, 0.25 x and 0.2 x PBS, the survival rates were 98%, 94%, 82%, 58% and 26% respectively. There was no statistical difference between 1.00 x and 0.50 x PBS group (P > 0.05). Although the rate in 0.30 x, 0.25 x and 0.20 x PBS group was significantly lower than in 1.00 x group(P < 0.01), it was significantly higher than in the same treatment group without in vitro culture(P < 0.05).

Animals↗
PubMed1999

Uncv (uncovered): a new mutation causing hairloss on mouse chromosome 11.

A pair of mutant mice with a first sparse coat appeared spontaneously in the production stock of BALB/c mice with a normal coat. After being sib-mated, they produced three phenotypes in their progeny: mice with normal hair, mice with a first sparse coat and then a fuzzy coat, and uncovered mice. Genetic studies revealed the mutants had inherited an autosomal monogene that was semi-dominant. By using 11 biochemical loci--Idh, Car2, Mup1, Pgm1, Hbb, Es1, Es10, Gdc, Ce2, Mod1 and Es3--as genetic markers, two-point linkage tests were made. The results showed the gene was assigned to chromosome 11. The result of a three-point test with Es3 and D11Mit8 (microsatellite DNA) as markers showed that the mutation was linked to Es3 with the recombination fraction 7.89 +/- 2.19%, and linked to D11Mit8 with the recombination fraction 26.30 +/- 3.57%. The recombination fraction between Es3 and D11Mit8 was 32.90 +/- 3.81%. It is suggested that the mutation is a new genetic locus that affected the skin and hair structure of the mouse. The mutation was named uncovered, with the symbol Uncv. Further studies showed the mutation affected not only the histology of skin and hair but also the growth and reproductive performance of the mice. The molecular characterization of the Uncv locus needs to be further studied.

Alopecia↗
PubMed1997

[Effects of age and ginsenoside RG1 on membrane fluidity of cortical cells in rats].

Membrane fluidity was measured using fluorescence spectrophotometer in cortical cells isolated from Wistar rats of five age groups (fetal); neonatal (3 days), young (3 months), adult (9 months) and old (27 months). Neurons were enzymatically isolated and loaded with the fluorescent dye, DPH (1,6-diphenyl-1,3,5-hexatriene). The membrane fluidity of neonatal cells was shown to be significantly higher (eta 1.485 +/- 0.211) than that in young cells (eta 2.220 +/- 0.169), and that in young cells was significantly higher than that in old cells (eta 2.842 +/- 0.143). No significant difference in fluidity, neither between fetal and neonatal cortical cells nor between young and adult ones was observed. Ginsenoside Rg1 (Rg1) is one of the important active principles of ginseng and shares many pharmacological effects of this plant. When treated with Rg1 (10, 20, 40 mg.kg-1), the membrane fluidity of old cortical cells significantly increased (eta 2.670 +/- 0.108, 2.381 +/- 0.123, 2.000 +/- 0.101). These findings indicate a substantial alteration of membrane fluidity with neuronal aging. Increment of membrane fluidity provides an aspect in elucidating the mechanisms of Rg1's antiaging action.

Aging↗
PubMed1997

[Effect of age and ginsenoside Rg1 on nitric oxide content and nitric oxide synthase activity of cerebral cortex in rats].

Nitric oxide(NO) content and nitric oxide synthase(NOS) activity were measured in cerebral cortex isolated from Wistar rats of three age groups(young: 3 months; adult: 9 months; and old: 27 months). No significant differences in NO content and NOS activity between young and adult rats were found(P > 0.05). The NO content and NOS activity in old rats were shown to be significantly higher than those of young and adult rats(P < 0.01). When treated with Rg1(10, 20, 40 mg.kg-1), the NO content and NOS activity in old rats decreased. The inhibitory effect of Rg1 on NOS was found to be dose-dependent in the range of 10-40 mg.kg-1. The optimal reduction in NO content and NOS activity induced by Rg1 occurred at 40 mg.kg-1 for old rats(P < 0.01). In view of the close relationship of NO content and NOS activity with aging, the inhibitory effect of Rg1 on NOS activity, as shown by our results, might provide an explanation for its antiaging function.

Aging↗
PubMed1997

[Study on the anti-apoptotic mechanism of ginsenoside Rg1 in cultured cortical neurons].

Ginsenoside Rg1 is an active principle isolated from Panax ginseng CA Meyer. Primary neuronal culture was performed with different concentrations of Rg1. On the 14th day, the culture was changed to serum-free medium. On the 16th day, neurons were harvested and assayed under microscope and fluorescence microscope. The result showed that serum withdrawal from the medium induced apoptosis in primary cultured cortical neurons. Rg1 (1, 10 mumol.L-1) was shown to inhibit apoptosis and protect neurons against injury. Membrane fluidity was measured using fluorescence spectrophotometer in five groups of cultured cortical neurons: control (complete medium), apoptosis (serum-free medium), Rg1 0.1 mumol.L-1, Rg1 1 mumol.L-1 and Rg1 10 mumol.L-1. Neurons were isolated enzymatically and loaded with the fluorescent dye, DPH (1, 6-diphenyl-1,3,5-hexatriene). Membrane fluidity in control neurons (eta 1.2928 +/- 0.1426) was shown to be significantly higher than that in apoptosis cells (eta 2.9277 +/- 0.2004). The membrane fluidity of neurons treated with Rg1 (0.1, 1, 10 mumol.L-1) increased significantly (eta 2.9172 +/- 0.1604, 2.4731 +/- 0.2187, 1.6436 +/- 0.1483). These findings indicate a substantial alteration of membrane fluidity with neuronal apoptosis. Increment of membrane fluidity provides an aspect of elucidating the mechanism of Rg1's anti-apoptosis function.

Animals↗
PubMed1995

Randomized study of chemoembolization as an adjuvant therapy for primary liver carcinoma after hepatectomy.

From April 1990 to December 1993, 140 patients were recruited to a randomized study to evaluate transcatheter hepatic arterial chemoembolization (TACE) as an adjuvant therapy for primary liver carcinoma after hepatectomy. This study investigated the principle, techniques and results of TACE. The results showed that the intrahepatic recurrence rate was 48.9% in the patients who underwent radical resection only, but only 21.3% in the patients who also underwent TACE 3-4 weeks after hepatectomy (P < 0.01). The 1-, 2-, 3-, and 4-year survival rates were 72.3%, 52.7%, 35.1%, and 35.1% respectively for the patients who underwent radical resection only, and were 97.9%, 85.5%, 69.5%, and 56.9% for the patients who also underwent TACE 3-4 weeks after radical resection (P < 0.001). The 1-, 2-, 3-, and 4-year survival rates were 38.9%, 0%, 0%, and 0% for the patients who underwent palliative resection only, and were 68.3%, 32.3%, 21.5%, and 21.5% respectively for the patients undergoing TACE 3-4 weeks after palliative hepatectomy (P < 0.001).

Adult↗