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Biomedical subjects

R Chen

Publications and source records attributed to R Chen.

At least 271 records · Page 15Linked to original sources
PubMed1999

Reciprocal actions of acupoints on gastrointestinal peristalsis during electroacupuncture in mice.

Orthogonal design was used to observe the gastrointestinal peristalsis in normal and atropine-treated mice after electroacupuncture was applied, singly or in combination, at Neiguan (P 6), Pishu (UB 20) and Zusanli (St 36). The results showed that: 1) electroacupuncture has no significant effect on the gastrointestinal peristalsis in normal mice; 2) Pishu (UB 20) was significantly antagonistic to Zusanli (St 36) in normal mice; 3) the decreased gastrointestinal peristalsis in atropine-treated mice was markedly promoted by electroacupuncture at Zusanli (St 36); and 4) Neiguan (P 6) was significantly antagonistic to Pishu (UB 20) in atropine-treated mice. The results indicated that the reciprocal actions among acupoints should be taken into consideration for point prescription.

Acupuncture Points↗
PubMed1999

[Cytotoxicities of low dose anticancer agents combining lymphokine activated killer cell against ovarian adenocarcinoma cell line SKOV3].

OBJECTIVE: To investigate whether low-dose anticancer agents could increase the sensitivity of ovarian adenocarcinoma cell line SKOV3 to lymphokine activated killer cell (LAK). METHODS: After SKOV3 cells were pretreated by low dose anticancer agents Taxol, cis-diamminedichloroplatin(CDDP), 5-fluorouracilum(5-FU) for 18 hours, the sensitivity of SKOV3 to LAK was detected by four 51Cr release assay. And the percentage of SKOV3 adhesion to LAK and intercellular adhesion molecule-1 (ICAM-1) expression on SKOV3 were detected by improved Grimm's assay and FACS respectively. RESULTS: After pretreatment of SKOV3 cell with 1.5 micrograms/ml Taxol, 4 micrograms/ml CDDP, 25 micrograms/ml 5-FU or without anticancer agents as control for 18 hours, the cytotoxicities of Interleukin-2 activated LAK against them were 29.7%, 45.9%, 37.2% and 28.5% respectively. The conjugation rates of SKOV3 and LAK were 20.1%, 26.1%, 24.9% and 18.7% respectively. The positive rates of ICAM-1 expression were 52.5%, 65.5%, 68.1% and 49.7% respectively. CDDP and 5-FU increased ICAM-1 expression significantly and the sensitivity of SKOV3 cell to LAK cell lysis was well related to the ICAM-1 expression. CONCLUSION: The results indicate that some low dose anticancer agents can increase the sensitivity of cancer cells to LAK cells and it would be useful in clinical practice.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1999

Personal opinion on the date of first printing of Jing yue quan shu (Jingyue's Complete Book).

Generally, the date of the first printing is based on the description, "Introduction to the Complete Book", in the postscript written by his grandson Lin Riwei, saying that "in the year of Gengchen (1) brought (my draft) to eastern Guangdong to tell the Fangbo master Lu... (who) donated his salary for the printing which lasted for several months". By Fangbo, it is another name for the position of Buzhengsi (Provincial administrative commissioner). Here, it refers to Lu Chao, by then the commissioner of Guangdong. In the Chronicle of Qing Officials, it is recorded that Lu Chao was in charge of Guangdong provincial commissioner in the year 37-40 of Kangxi reign (1688-1671). Together with other reference data, I draw the conclusion that Jingyue's Complete Book should be first printed in the year 1700.

China↗
PubMed1999

[A comparative analysis of clinical and pathologic diagnoses in 79 pediatric autopsy cases].

This study is a comparative analysis between pathologic and clinical diagnoses of 79 pediatric autopsy cases. We found that 14 cases were misdiagnosed. The rate of misdiagnosis is 17.72%. The 79 cases were divided into four groups of children aged approximately 28 days, approximately 5 years, approximately 10 years and approximately 14 years, the rate of misdiagnosis of the first group is 29.63%. This rate is apparently higher than other age groups(P < 0.05). The younger the age group is, the higher the chances of misdiagnosis. Respiratory disease was the main misdiagnosis rating 42.86%, while the two misdiagnosed cases were found to be tuberculosis. We suggest that doctors be aware of the perinatal factor when they diagnose newborns and try to find out the primary cause of illness, the threat of tuberculosis to children. Pediatricians should heed.

Adolescent↗
PubMed1999

[Acceleration of wound healing in diabetic rats by PDWHF and its relation with its activity to stimulate procollagen I (alpha 1) gene expression].

OBJECTIVE: The effect of platelet-derived wound healing factor (PDWHF) on wound healing in diabetic rats was studied. METHODS: Forty-four male SD rats were randomly divided into 2 groups. Thirty-two rats of experimental group accepted intraperitoneal injection of alloxan (1.5 mg/10 g body weight). Within one or two days after injection, while the blood sugar of the rats was higher than 180 mg/dl, the animal model of diabetic rat should have been established. Then a dorsal incision was given to every rat. After the addition of PDWHF (the experimental group) or bovine albumin (the control group), the incision was sutured up. Seven, ten and fourteen days after operation, the breaking strength of the wound was measured. On another hand, specimen from the wound was taken for the culture of fibroblasts. When the cultured fibroblasts have been incubated with 10% PDWHF for 4, 8 and 12 hours, the procollagen I (alpha 1) mRNA levels were examined respectively, and compared with those of control. RESULTS: Significant difference in wound breaking strength had been observed between PDWHF-treated incisions and the control on 7, 10 and 14 days after wounding (P < 0.01). Experiment in vitro demonstrated that the procollagen I (alpha 1) mRNA levels in wound fibroblasts incubated with 10% PDWHF for 4, 8 and 12 hours were 0.9, 3.7 and 2.2 folds higher than those in fibroblasts in control. CONCLUSION: It was suggested that direct stimulation of procollagen I (alpha 1) gene expression was one of the ways that PDWHF played its role in accelerating wound healing.

Animals↗
PubMed1999

[Investigating the phenomenon of total erythrocyte destruction during an in-vitro hemolysis test by roller pump].

This study sought to address the question, "will the phenomenon of 'total erythrocyte destruction' come about during a long time of in vitro hemolysis test by roller pump". One-day-old boving blood was employed in the test by Polystan pump(group A) and Cobe pump (group B). TMB method was used to measure the level of plasma-free hemoglobin. The samples of plasma-free hemoglobin were taken at the time before pumping and pumping for 4,6,8,10, 12,14 and 16 hours. The index of hemolysis was calculated according to Koller's formula. The results showed that the levels of plasma-free hemoglobin in the two groups both increased linearly during the puming of blood. The index of hemolysis was 0.2960 mg/L group A, and 0.3993 mg/L in group B; no statistically significant difference was noted between the two groups. These data indicated that no phenomenon of "total erythrocyte destruction" was observed in this hemolysis test by roller pump.

Erythrocytes↗
PubMed1999

[The protective effect against Toxoplasma infection in mice immunized with laser-irradiated Toxoplasma tachyzoites].

AIM: To observe the level of immune responses and protective immunity in mice induced by laser-irradiated Toxoplasma tachyzoites (LIT). METHODS: ICR mice were immunized with LIT. After one month, the mice were challenged with live Toxoplasma tachyzoites to observe the effect of LIT. Indirect immunofluorescence assay and ELISA were used to detect CD4+/CD8+ lymphocyte subpopulation and IgG antibody. RESULTS: Immunization with LIT could partially protect the mice from Toxoplasma infection, prolong the survival time, enhance the CD4+/CD8+ ratio and produce specific IgG antibody. CONCLUSION: Intraperitoneal injection with LIT can induce partial protective immunity and specifically elicit ICR mice to generate humoral and cell-mediated immune responses.

Animals↗
PubMed1999

[Luminescence characteristics of simple fluorides containing Ce3+ and Tb3+ ions].

A series of phosphors containing Ce3+, Tb3+ ions in CaF2 and AlF3 were synthesized in a solution reaction and solid reaction method. Their excitation and emission spectra were determined. The results indicated that Ce3+ could not effectively transfer energy to Tb3+ in matrix CaF2 and AlF3 and enhance the emission of Tb3+ significantly.

English Abstract↗
PubMed1999

[Studies on tailed metalloporphyrin coordination compounds. IX. Synthesis of tailed porphyrin with covalently linked phenylalanine and its fluorescence property].

A new tailed porphyrin with covalently linked phenylalanine 2 and its zinc complex 3 were synthesized. Intramolecular energy transfer (from singlet excited phenylalanine to porphyrin) was observed in compound 2 and 3. The influence of coordination chemistry factor on the fluorescence of porphyrin was also discussed.

Energy Transfer↗
PubMed1999

[INDO/CI studies on the electronic spectra of tetraphenylporphyrin and its derivatives].

MNDO calculations and group theory were carried out on tetraphenylporphyrine (TPP) to obtain its optimum molecular geometry. We employed an INDO/CI method to study the electronic structures of tetraphenylporphyrine and its derivatives and identify their main electonic absorption bands. Five-orbital model was advanced to explain the typical characteristics of electronic spectra of H2TPP and its derivatives. The calculated wavelengths were in good agreement with the experimental values. The effects of the substitution of variant group were discussed and some helpful conclusions were drawn.

Models, Molecular↗
PubMed1999

[Determination of the content of aminopyrine in antongding injection by orthogonal function spectrophotometry].

Determination of the content of aminopyrine in the antongding injection by orthogonal function spectrophotometry was reported in this paper. The six wavelengths for the determination are 257, 261, 265, 269, 273 and 277 nm. The concentration of aminopyrine in the range of 5-25 microg x mL(-1) is in a good linear relation to P2, and the regression equation is P2 = + 0.018 - 0.032 9c, r = 0.999 9. The average recovery and relative standard deviation are 100.3% and 0.40%, respectively. On the basis of the data observed it is concluded that this method shows no obvious difference as compared with Hebei province pharmacy regulation.

Aminopyrine↗
PubMed1999

[Determination of sulfur dioxide by fluorometric analysis].

A method to determine the concentration of atmospheric pollutant, sulfur dioxide, was studied by fluorophotometric method. The composition and concentration of reaction solution were optimized. This method can be developed to be a fibre optic fluorometric method for routine monitoring.

Air Pollutants↗
PubMed1998

Stat6 inhibits human interleukin-4 promoter activity in T cells.

The differentiation of naive T-helper (Th) cells into cytokine-secreting effector Th cells requires exposure to multiple signals, including exogenous cytokines. Interleukin-4 (IL-4) plays a major role in this process by promoting the differentiation of IL-4-secreting Th2 cells. In Th2 cells, IL-4 gene expression is tightly controlled at the level of transcription by the coordinated binding of multiple transcription factors to regulatory elements in the proximal promoter region. Nuclear factor of activated T cell (NFAT) family members play a critical role in regulating IL-4 transcription and interact with up to five sequences (termed P0 through P4) in the IL-4 promoter. The molecular mechanisms by which IL-4 induces expression of the IL-4 gene are not known, although the IL-4-activated transcription factor signal transducer and activator of transcription 6 (Stat6) is required for this effect. We report here that Stat6 interacts with three binding sites in the human IL-4 promoter by electrophoretic mobility shift assays. These sites overlap the P1, P2, and P4 NFAT elements. To investigate the role of Stat6 in regulating IL-4 transcription, we used Stat6-deficient Jurkat T cells with different intact IL-4 promoter constructs in cotransfection assays. We show that, whereas a multimerized response element from the germline IgE promoter was highly induced by IL-4 in Stat6-expressing Jurkat cells, the intact human IL-4 promoter was repressed under similar conditions. We conclude that the function of Stat6 is highly dependent on promoter context and that this factor promotes IL-4 gene expression in an indirect manner.

Binding Sites↗
PubMed1998

The arabidopsis thaliana AGRAVITROPIC 1 gene encodes a component of the polar-auxin-transport efflux carrier.

Auxins are plant hormones that mediate many aspects of plant growth and development. In higher plants, auxins are polarly transported from sites of synthesis in the shoot apex to their sites of action in the basal regions of shoots and in roots. Polar auxin transport is an important aspect of auxin functions and is mediated by cellular influx and efflux carriers. Little is known about the molecular identity of its regulatory component, the efflux carrier [Estelle, M. (1996) Current Biol. 6, 1589-1591]. Here we show that mutations in the Arabidopsis thaliana AGRAVITROPIC 1 (AGR1) gene involved in root gravitropism confer increased root-growth sensitivity to auxin and decreased sensitivity to ethylene and an auxin transport inhibitor, and cause retention of exogenously added auxin in root tip cells. We used positional cloning to show that AGR1 encodes a putative transmembrane protein whose amino acid sequence shares homologies with bacterial transporters. When expressed in Saccharomyces cerevisiae, AGR1 promotes an increased efflux of radiolabeled IAA from the cells and confers increased resistance to fluoro-IAA, a toxic IAA-derived compound. AGR1 transcripts were localized to the root distal elongation zone, a region undergoing a curvature response upon gravistimulation. We have identified several AGR1-related genes in Arabidopsis, suggesting a global role of this gene family in the control of auxin-regulated growth and developmental processes.

Amino Acid Sequence↗