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Biomedical subjects

C Guo

Publications and source records attributed to C Guo.

At least 109 records · Page 6Linked to original sources
PubMed1999

[Carcinoma of the lips developing in discoid lupus erythematosus].

OBJECTIVE: This clinical study was designed to learn the diagnosis and treatment of lip carcinoma developing in discoid lupus erythematosus. METHODS: One hundred and eighty-one of squamous cell carcinoma of the lips treated in our department from 1980 to 1995 were retrospectively studied. RESULTS: Ten cases of the 181 lip carcinoma (5.5%) had concomitant discoid lupus erythematosus (DLE) of the vermilion border of the lower lip. CONCLUSION: Bleomycin or radiotherapy is the best treatment for the disease.

Adult↗
PubMed1999

[Determination of stilbene in radix Polygoni multiflori by HPLC and its stability study].

OBJECTIVE: To develop a HPLC method for determining stilbene in Radix Polygoni Multiflori and studying its stability. METHOD: HPLC conditions: An Econosphere C18 column, a mixture of methanol-water(30:70) as mobile phase, and UV detection at 310 nm. In addition, the stability of stilbene was studied at high temperature and in acidic solution. RESULT: The linear range of calibration curve was 2.24 x 10(-2)-1.12 x 10(-1) micrograms(n = 6) with a correlation coefficient of 0.99998, the average recovery with RSD being 99.96% +/- 1.54%. CONCLUSION: The method is sensitive, accurate and speedy. Stilbene in aqueous solution is stable, but high temperature(80 degrees C) tends to affect the stability. In acidic solution no stability can be found.

Drug Stability↗
PubMed1999

[Neural cluster structure with single component prediction in multiple variable systems for X-ray fluorescence spectrometry].

A neural cluster structure with single component prediction (NCSCP) was proposed for X-ray fluorescence spectrometry in a multivariable system. The neural cluster structure is built by the collection of a group of neurons which have close relationships among one another. In X-ray fluorescence analysis, the structure is constructed by choosing the elements in which there exist serious matrix effects, and deleting the components containing large noise. The predictability of the neural cluster structure was compared with that of the classical backward error propagation algorithm with single component prediction. The results show that the neural cluster structure is significantly superior to the classical algorithm in prediction accuracy, antidisturbance and the predictabilty to outliers.

English Abstract↗
PubMed1999

[Study on luminescence of the serial new ternary or tetradic complexes complexes of Eu (III) with beta-diketone].

The UV absorption, fluorescence, unstable spectra and quantum yields of five ternary or tetradic complexes of Eu (III) with beta-diketone (dibenzoyl methane, thenoyltrifluoroacetone), acrylic acid and other ligands were reported. The influences of the first and second ligands on absorption and luminescence spectra were found. The lifetimes and the processes of energy transfer of Eu3+ from 5D1 to 5D0 in complex solutions were measured. It was found that the lifetimes of Eu3+ complexes with TTA are approximate to each other and larger than those of complexes with DBM.

English Abstract↗
PubMed1998

Differential stimulation of proline-rich tyrosine kinase 2 and mitogen-activated protein kinase by sphingosine 1-phosphate.

Sphingosine 1-phosphate (SphP), a metabolite of cellular sphingolipids, has been shown to induce cell proliferation by activating the mitogen-activated protein kinase (MAPK) pathway. Proline-rich tyrosine kinase 2 (Pyk2) is a novel cytosolic tyrosine kinase which mediates activation of the MAPK or c-Jun N-terminal kinase (JNK) signaling pathways in response to a variety of stimuli that elevate intracellular calcium. In this report, we show that SphP stimulates both tyrosine phosphorylation of Pyk2 and MAPK activation in a transient and dose-dependent manner in rat aortic smooth muscle cells. Further studies indicate that Pyk2 phosphorylation, but not MAPK activation, is dependent on a pertussis toxin-sensitive G-protein-coupled receptor as well as partially on actin cytoskeleton. In addition, both intracellular calcium mobilization and protein kinase C (PKC) are required for optimal Pyk2 phosphorylation while either calcium increase or PKC activation is sufficient for MAPK activation in response to SphP. Finally, we show that a tyrosine kinase(s) other than Pyk2 is necessary for MAPK activation by SphP. Together, these results suggest that SphP stimulates tyrosine phosphorylation of Pyk2 through a G-protein coupled receptor, which is dissociated from its activation of the MAPK pathway in these cells.

Animals↗
PubMed1998

Dynamics of protein kinase CK2 association with nucleosomes in relation to transcriptional activity.

Protein kinase CK2 has been implicated in control of cell growth and proliferation. Since growth stimuli evoke its preferential association with chromatin and nuclear matrix, we examined the dynamics of CK2 in nucleosomes fractionated on the basis of their transcriptional activity in the rat prostate. In this model, androgens induce expression of androgen-dependent genes but inhibit the androgen-repressed genes, whereas absence of androgens has the reverse effect. The level of CK2 was higher in the active than in inactive nucleosomes from normal prostate. Differential alterations in the levels of CK2 activity in the transcriptionally active versus inactive nucleosomes were evoked by androgen deprivation or administration. Comparison of the distribution of CK2 in active and inactive nucleosomes under varying androgenic conditions showed that the relative CK2 activity intrinsic to the transcriptionally active nucleosomes remained fairly stable, concordant with gene activity specific to the androgenic status. However, CK2 associated with inactive nucleosomes declined to a minimal level on androgen deprivation but increased rapidly on androgen administration (reflecting expression of multiple androgen-dependent genes). We suggest a role for CK2 in promoting the conformational transition of inactive nucleosomes to the active form and in the function of transcriptionally active nucleosomes.

Androgens↗
PubMed1998

[Polymorphism analysis of 4 loci of X-chromosome in a Chinese population of the Han nationality].

OBJECTIVE: To investigate the polymorphism of 4 loci of X-chromosome in the Hans. METHODS: Using PCR-SSLP, the authors analysed the polymorphism of DXS1068, DXS7132, DXS6804 and DXS6799 in the X-chromosome in 70 randomly selected female Hans. RESULTS: The number of alleles in the 4 loci were 5,5,5 and 6 respectively; there were no significant differences between the observed and estimated and genotype probabilities of the 4 loci; the estimates of heterozygosity of 4 loci were 0.6819, 0.6895, 0.7659 and 0.6483 respectively and there were no significant differences between the observed and estimated heterozygosity of the 4 loci. CONCLUSION: The distribution of alleles and genotype probabilities of 4 loci all observe the Hardy-Weinberg equilibrium.

Asian People↗
PubMed1998

[A study of genetic patterns of idiopathic epilepsy].

OBJECTIVE: To explore genetic patterns of idiopathic epilepsy (IEP). METHODS: Using familial analysis, tests for multifactorial inheritance and segregation analysis, we studied 210 pedigrees with IEP found in a population survey in Shangdong province. RESULTS: The genetic pattern of IEP is not polygenic but is mainly influenced by autosomal recessive disorders. The results of segregation analysis indicate that the genetic pattern of U*U multiplex families and U*A group is autosomal recessive. Only a few cases in U*U group may accept the assumption of autosomal recessive inheritance while the other are sporadic cases. The frequency of sporadic cases is approximately 78.5%. Genetic heterogeneity may influence U*U(f) group and U*U group. CONCLUSION: Further and careful empirical scrutiny of U*U(f) group and the sporadic cases in U*U group offers the best hope for getting a clear understanding of genetic patterns and mechanisms in IEP.

Epilepsy↗
PubMed1998

Differential regulation of Pyk2 and focal adhesion kinase (FAK). The C-terminal domain of FAK confers response to cell adhesion.

Pyk2 is a recently described cytoplasmic tyrosine kinase that is related to focal adhesion kinase (FAK) and can be activated by a variety of stimuli that elevate intracellular calcium. In this report, we showed that Pyk2 and FAK tyrosine phosphorylation are regulated differentially by integrin-mediated cell adhesion and soluble factors both in rat aortic smooth muscle cells, which express endogenous Pyk2 and FAK, and in transfected Chinese hamster ovary cells. We also found that Pyk2 is diffusely present throughout the cytoplasm, while FAK is localized in focal contacts as expected, suggesting that the different localization may account for their differential regulation. By analyzing a chimeric protein contain N-terminal and kinase domains of Pyk2 and C-terminal domain of FAK, we provided evidence that the distinctive C-terminal domains of Pyk2 and FAK were responsible for their differential regulation by integrins and soluble stimuli as well as their subcellular localization. Finally, we correlated FAK, Pyk2, and the chimeric protein binding to talin, but not paxillin, with their regulation by integrins and focal contact localization. These results demonstrate that the distinctive C-terminal domain of Pyk2 and FAK confer their differential regulation by different subcellular localization and association with the cytoskeletal protein talin.

Amino Acid Sequence↗
PubMed1998

Relationship between lung function and blood pressure in Chinese men and women of Beijing and Guangzhou. PRC-USA Cardiovascular and Cardiopulmonary Epidemiology Research Group.

BACKGROUND: Previous studies of western populations have shown an inverse association between lung function and blood pressure. METHODS: As part of a People's Republic of China-United States cardiopulmonary epidemiology study, we investigated the cross-sectional relationship between lung function and blood pressure in 6757 Chinese men and women, aged 35-54, from Beijing and Guangzhou, China. We also evaluated the longitudinal association between lung function and incident hypertension among 4818 initially normotensive subjects followed up between 2 and 4 years later. RESULTS: In our cross-sectional analyses of baseline data, lung function varied inversely with baseline systolic (SBP) and diastolic blood pressure (DBP) in all women and in Beijing men. This association held for absolute and height-standardized forced vital capacity (FVC) and one-second forced expiratory volume (FEV1) (correlations: 0.10, -0.18, P < 0.0001), but was weaker after adjustment for age (correlations: -0.02, -0.11). The longitudinal follow-up showed that lower initial lung function levels were associated with a higher incidence of hypertension (SBP > or = 140 mmHg or DBP > or = 90 mmHg or currently using antihypertensive medications), but only among women in Guangzhou. Relative risks for hypertension incidence for those in the two lowest quintiles for FEV1 and FVC, compared to those in the two highest quintiles, ranged from 1.9 to 2.3 for Guangzhou women and from 0.9 to 1.4 for all other gender-city subgroups. Logistic regression analyses adjusting for age, baseline SBP, body mass index, smoking, education, and urban versus rural setting generally confirmed these patterns. CONCLUSIONS: These results suggest a statistically significant, though weak, inverse relationship between lung function and blood pressure in Chinese men and women. This association is largely attributable to age and is present prospectively only in women.

Adult↗
PubMed1998

[An experimental study on promoting reconstruction of microcirculation of the ischemic skin flap with basic fibroblast growth factor].

OBJECTIVE: This study was to determine whether the basic fibroblast growth factor (bFGF) could promote reconstruction of microcirculation in the ischemic portion of a random skin flap. METHODS: Five methods were used in the experiment: measurement of the survival area of the skin flap; light and electron microscopic studies; immunohistochemical observation of the endothelial cell and microvessel image analysis technology (IAT). RESULT: The survival area and microvessels in the skin flap were significantly increased in the treated group. The results indicate that bFGF can stimulate the proliferation and differentiation of endothelial cells in vivo and promote the microcirculation of the ischemic flap. CONCLUSION: bFGF could promote reconstruction of microcirculation of the ischemic skin flap.

Animals↗
PubMed1998

[Effect of dietary calcium on serum calcium and calmodulin activity of brain and hypothalamus in rats].

The effect of low calcium (LC) diet supplemented with various amount of calcium on serum calcium and calmodulin of rats was studied. The LC diet was mainly composed of corn low in calcium. The calcium content of LC diet was only half of that of the stock diet. Seventy Wistar rats were divided into 7 groups by weight and sex. Results showed that serum calcium in LC group was low and calmodulin activity was also low. These parameters were improved while calcium was supplemented in LC diet. There is a significant dose-response relationship among diet calcium, serum calcium and growth. When the total calcium in diet was increased up to 1000 mg/kg, serum calcium level was closed to that of normal and higher than the serum calcium in LC group significantly. The study demonstrated that low dietary calcium, hypocalcemia and low calmodulin are associated. When total dietary calcium was up to 1000 mg/kg, the growth retardation was attenuated.

Animals↗