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Biomedical subjects

S Chen

Publications and source records attributed to S Chen.

At least 1,009 records · Page 56Linked to original sources
PubMed1996

[High homology between antigen of HFRSV with anti-idiotype antibody against HFRSY].

OBJECTIVE: To detect the structural characterization of genes of the anti-idiotype antibody and the antigen. METHODS: The hybridoma (C8) secreted the anti-idiotype human McAb against hemorrhagic fever virus (HFRSV). The variable region genes of heavy and light chain of the anti-Id huMcAb were cloned. The homology was analysed between the variable region genes and the genes of HFRSV. RESULTS: The 45-55 amino acids of VH and 58-68 amino acids of VL were highly homologic to the 447-457 amino acids of G2 protein in Hantaan virus. And the homologeneous regions were similar in secondary structure of the three proteins. CONCLUSION: There is a molecular basis in the anti-idiotype antibody imaging antigen.

Antibodies, Anti-Idiotypic↗
PubMed1996

[The mechanisms of ET-1-induced lung edema].

OBJECTIVE: To investigate the machanisms of ET-1-induced lung edema. METHODS: Different doses of ET-1 were added to isolate rat lungs perfused by Ringer's solution containing albumin to explore the mechanisms of ET-1 induced pulmonary edema. The lung weight gain, pulmonary vascular permeability to water (Wf) and albumin (Ps) were observed. RESULTS: It was found that low dose ET-1 increased lung weight gain, pulmonary artery pressure, pulmonary capillary pressure, pulmonary vascular post-resistance and total resistance, but no significant changes of vascular permeability were observed. CONCLUSION: The mechanisms of lung edema induced by ET-1 are different. Low dose ET-1 may induce lung edema by increasing pulmonary vascular permeability while large dose ET-1 by increasing pulmonary vascular pressure.

Animals↗
PubMed1996

[A study of HIA-DR antigen expression in nasopharyngeal carcinoma and its relation with clinical pathology and prognosis].

In order to clarify the relationship between HLA-DR antigen expression of nasopharyngeal carcinoma (NPC) and the clinicopathology and prognosis of NPC, immunohistochemical studies on HLA-DR antigen expression in 77 NPC cases were performed. The results showed that the positive rate of HLA-DR was 44.2% in this series. Non-neoplastic epithelium did not express this antigen. A close association was found between expression of HLA-DR antigen and the clinical staging of NPC. The positive rate of HLA-DR gradually decreased with tumor progression, showing a remarkable difference among tumors in different clinical stages (P < 0.05). Analysis of patient survival demonstrated that the prognosis of NPC patients with HLA-DR expression was significantly better than those without (P < 0.01). The above results give support to the possibility of immunomodulation of tumors.

Adult↗
PubMed1996

[Influence of neuronal excitation and inhibition of rostral ventrolateral medulla on the effect of electroacupuncture of "Neiguan" acupoint].

Experiments were performed on 44 rabbits anesthetized with a mixture of urethane and chloralose. The effects of microinjection of glutamate and glycine in bilateral rostral ventrolateral medulla (rVLM) on the reaction of electroacupuncture (EA) of "Neiguan" acupoint (PC 6) after myocardial ischemia by ligature of the left ventricular branch of coronary artery were observed. Results showed that (1) EA could significantly promote the recovery of ECG ST-segments, mean blood pressure (MBP), left ventricular pressure (LVP) and the maximum rising rate of LVP (dp/dt max); (2) Glutamate could enhance the effects of EA on MBP, LVP and dp/dt max to a certain extent; (3) The effects of EA could be weakened significantly by glycine. It suggests that EA-induced improvement of the cardiovascular function can be strengthened further in some degree when neurons of rVLM are excited and weakened pronouncedly while the neurons are inhibited. Therefore, rVLM participates in the regulatory process of EA on functional activity of the heart.

Acupuncture Points↗
PubMed1996

[A study on the reflex arc outside the central nervous system with sympathetic ganglia as the centre].

The distribution of SP-like immunoreactivity in the sensory and sympathetic ganglia, as well as the fiber connection between sensory ganglia and sympathetic ganglia (SG) were studied by the immunohistochemical ABC and HRP methods. A large number of SP-like neurons were found in all dorsal root ganglia (DRG), and a large number of SP-like fibers and terminals were found in both thoracic SG and coeliac-cranial mesenteric ganglion complex (CCMG), but no SP positive perikaryons were seen in those ganglia. The various nerves connected with the CCMG have been cut, the results demonstrate that the SP immunoreactive material in the ganglion were only decreased obviously or disappeared by cutting the DRG associated with the CCMG. After injecting HRP into T7-9DRG, a few of labelled neurons were found in thoracic SG of the relative segments and CCMG. The results mentioned above revealed that SP-containing fibers and terminals present in the SG come from collateral branches of primary sensory neurons in the DRG, the postganglionic fibers from principal ganglion neurons in the SG projecting to the DRG, the connection of reciprocal fibers are present between the DRG and the SG. It is suggested that a reflex shortloop outside the central nervous system may be formed directly by primary afferent neuron and sympathetic postganglionic neuron for the purpose of regulating the activity of autonomic nervous system and, moreover the sympathetic nerve may have a feedback regulation function to the primary afferent. The results mentioned above offer the partial morphological testimony for the expoundity of acupuncture mechanism.

Animals↗
PubMed1996

[Influence of microinjection of clonidine and yohimbine in rVLM on the effect of electroacupuncture treatment of myocardial ischemia].

In the present paper, influence of microinjection of clonidine (Clon, 0.38 mMol, 2 microliters) and yohimbine (Yoh, 5.1 mMol, 2 microliters) in rostral ventrolateral medulla (rVLM) on the effect of electroacupuncture (EA) at Neiguan (PC 6) was observed in the rabbit with acute myocardial ischemia. Results showed that (1) EA of Neiguan could significantly accelerate the recovery of AMI-induced changes in ECG ST-segement, mean blood pressure, left ventricular pressure (LVP) and dp/dt max; (2) Clon strengthened the effect of EA on ST and LVP in some degree; and (3) Yoh significantly weakened the effect of EA on ST and LVP. It reveals that when alpha 2 receptors of rVLM are excited, the favourable effect of EA in regulating post-ischemic myocardial electrical and mechanical activity can be enhanced in some degree; and when they are inhibited, the effect of EA disappears, indicating an involvement of alpha 2 receptors of rVLM in EA of Neiguan-induced regulation on the functional activity of the heart.

Adrenergic alpha-Agonists↗
PubMed1996

[Specific binding of human bone morphogenetic protein (2A) with mouse osteoblastic cells].

Human bone morphogenetic protein 2A (hBMP2A) cDNA terminal S67 nucleotides were cloned and expressed in a phage display vector pCSM21. Human BMP2A C-terminal peptide displayed on the surface of the phage can bind specifically to the surface of mouse osteoblastic cell (MC3T3) membrane. ELISA assay showed a positive signal of the binding by using antibody against M13 phage gene 8 protein. After labeling with 3HTdR, the counts of the binding groups were 3 to 10 times higher than the control groups. It suggests that the surface of MC3T3 cells exist the receptor for hBMP2A.

Animals↗
PubMed1996

[Labour induction in women at term with mifepristone and misoprostol].

OBJECTIVE: To determine the efficacy of mifepristone (RU486) combined with misoprostol as an induction agent for the initiation of labour in women at term. METHODS: Our study group contained 68 pregnant women at term (gestational age: 38-41 weeks) who had clear clinical indications for labour induction. They received mifepristone either 150 mg or 200 mg respectively in the first two or three days. The shortening of the cervical length, the change of Bishop score and the change of the blood serum in oestradiol (E2) concentration and progesterone (P) concentration were observed respectively before and after medication. On the fourth day, misoprostol was added from 100 micrograms to 300 micrograms successively. The outcome of labour induction in these women was recorded. RESULTS: The cervical length of women who were given mifepristone was 1-3 cm shorter and Bishop score was 4-5 higher than those before treatment. The E2 concentration and the P concentration were significantly higher and lower respectively than those before treatment. The cervical ripening ratio was 100.00%. The incidence of the onset of labor was 93.00% and the incidence of vaginally delivery was 80.88% after misoproston was given. CONCLUSION: Mifepristone combined with misoprostol is a safe, efficient, economical and convenient induction agent for initiation of labor in women at term.

Abortifacient Agents, Nonsteroidal↗
PubMed1996

[A study of the effects of chemotherapy with or without G-CSF on neutrophil counts and serum G-CSF levels in leukemia patients].

For studying the relation between the serum G-CSF levels and neutrophil counts, consecutive changes of G-CSF levels and neutrophil counts in 20 cases of acute leukemia receiving chemotherapy with or without administration of G-CSF were observed. The G-CSF levels were detected by ELISA. The results showed: (1) Before chemotherapy G-CSF levels were higher than normal value in acute leukemia patients. (2) Four patterns of consecutive change of serum G-CSF levels in 19 cases receiving chemotherapy alone were observed, viz curves with double peaks, single peak, V type and declining type. Different patterns of G-CSF change were accompanied with different changes of neutrophil counts. (3) Both serum G-CSF levels and neutrophil counts were elevated significantly in nine cases receiving G-CSF after chemotherapy. (4) Comparing chemotherapy with and without G-CSF treatment. The time required for neutrophil count to reach a level more than 1.5 x 10(9)/L was significantly shorter in those administering G-CSF after chemotherapy than the patients not using G-CSF. These results suggest that observation of the changes of serum G-CSF levels is helpful in judging myelosuppression and marrow recovery after chemotherapy. Administration of G-CSF is an effective method to increase the neutrophil counts and to shorten the myelosuppressive period.

Acute Disease↗
PubMed1996

[A study on methodology and the criteria for positive immunohistostaining of estrogen and progesterone receptors in paraffin embedded sections of breast cancer].

The expression of estrogen receptor (ER) and progesterone receptor (PR) in 200 breast cancer specimens were imvestigated by monoclonal antibody with S-P staining to evaluate and standardize the criteria for positive staining. The results revealed that the incidence of ER and PR were 73.5% and 65.5% respectively. The authors concluded that the immunostaining could demonstrate in situ ER and PR, the results were stable, highly sensitive, consistent and comparable with the well established and recognized techniques home and abroad. The authors further pointed out that the crucial point of the staining is antigen retrieval and reported the optimal temperature and the time of sodium citrate buffer treatment. In this report, the criteria for positive staining were discussed intensively. The observations indicated that the percentage of the positive cells is more reliable, representative and practical than that of positive staining intensity index.

Breast Neoplasms↗
PubMed1996

[An investigation of immunoreactive substances in normal gingival tissue and periodontitis tissue].

In order to study the effects of NO, endothelin (ET), substancep (SP) and caleiton gene-related paptide (CGRP) immunoreactive substances in chronic periodontitis tissue and the relationship with periodontitis, immunohistochemical and histochemical staining methods were used respectively to detect the expression of the above immunoreactive substances in 20 patients with chronic periodontitis. Quantitative analysis showed that NO and ET in periodontitis tissues were increased significantly (P < 0.01), particularly the content of ET, in comparison to normal tissue. Due to the increase of ET content, the bolld supply was diminished and influenced the periodontal tissue by causing tissue damage. This study suggests that NO and ET immunoreactive substances are closely associated with periodontitis and may play an important role in the disease. There were no marked changes on SP and CGRP.

Calcitonin Gene-Related Peptide↗
PubMed1996

[Combined effects of high temperature and carbon monoxide on heat stress protein levels in rat brain and viscera].

Combined effects of high temperature and carbon monoxide (CO) on the amounts of heat stress protein 60 (HSP 60) and 70 (HSP 70) in rat brain and viscera were studied by western dot blot technique. Results showed that (1) amounts of HSP 60 in rat brain, spleen and kidney, as well as its rectal temperature, increased with CO concentrations, while those in heart decreased; and both of them showed synergistic effects on those in spleen and kidney, antagonistic ones in brain and liver, and synergistic ones of lowering them in heart; (2) amounts of HSP 70 changed with CO concentrations in five rat viscera, with synergism in brain, and antagonism in other organs; and (3) amounts of HSP 60 and 70 in most rat viscera and their body temperature were the most sensitive to 693.6 mg/m3 of CO.

Animals↗
PubMed1996

[The cloning and expression of salmon calcitonin gene in Escherichia coli].

The DNA fragment encoding salmon calcitonin was separated from the salmon DNA with PCR method. It was recombined into the fusion expression vector (pGEX-2T) which included a Glutathion-S-Transferase (GST) gene and was transformed into E. coli JM109 and then expression was induced with IPTG. The fusion protein (GST-sCT) accounted for 38%-40% of the total cellular protein and was purified from the soluble expression products by glutathion sepharose 4B affinity chromatography. The purity of GST-sCT is about 80% and it showed a positive immunological reaction in calcitonin enzyme immunoassay.

Amino Acid Sequence↗
PubMed1996

[Increased promoter activity of human delta-globin gene with point mutation of C-T at site-64].

With PCR point mutation technique, the CCAAC box in the promoter region of delta-globin gene was changed into CCAAT which is required in the normal transcription of beta-globin gene at the corresponding site. The normal and mutant segments of the delta-globin promoter region obtained with each segment of about 300 bp (-280/+54 bp), a fragment sufficient for the requirement of its normal promoter function, were separately cloned into pUC19/Hinc II. After sequencing, it showed that the CCAAC box had been successfully changed into CCAAT without other mutations. The two segments were released by Nco I and BamH I, and were cloned into the corresponding site of plasmid pMG3 which has the firefly luciferase as its reporter gene. The positive clones were selected by Dot Blot and were comfirmed with restriction mapping. Then the two recombinant plasmids were transfected into HeLa cell line respectively and the promoter activities of the two fragments were identified by comparing the light intensity generated by the cell extracts when added with luciferase assay substrate. The results demonstrated that the luminescence of the mutant group is on average five times higher than that of the normal group, which indicate that the C-T mutation of the CCAAC box of delta-globin promoter region could increase its promoter activity. Our results have confirmed the hypothesis that the sequence of CCAAC box of human delta-globin gene is one of the main reasons which accounts for its low expression level. The author is now studying the specific DNA binding protein of the upstream promoter region of human delta-globin gene.

Globins↗
PubMed1996

[A morphometric study on hippocampus of epileptic rats induced by coriaria lactone].

This experiment was carried out with these rats were injected with 3.8 microliters (19 micrograms) convulsive dosage of coriaria lactone (CL) in the left cerebral motor cortex of the forelimb to induce acute focal epilepsy, while the other 5 rats as controls (no seizure) received normal saline solution of the same volume and at the same location. The brains were taken after seizuring for 60 min. The volume (water displacement method) and weight of the brain were measured. The brain was cut coronally and the structures of hippocampus were compared morphologically with those of the pair-matched control. The area of hippocampal formation was measured with paraffin section by test grid under 40x. The mean size (Feret's diameter) of pyramidal neurons in CA1 region was measured with semithin section by ocular micrometer under 1000x. The areal fraction of several organelles of the CA1 pyramidal cells was measured with EM negative film by magnifier. Under conditions of the consistent reference space, especially the size of CA1 pyramidal cells, the areal fraction of rough endoplasmic reticulum, lysosome and mitochondria increased significantly (P < 0.05) in epileptic rats. It indicated that their volume increased. The results show that certain ultrastructural changes have taken place after seizuring for 60 min.

Animals↗
PubMed1996

Comparative study on the mechanism of formation of pulse manifestations in coronary heart disease and hematopathic patients.

Most patients suffering from coronary heart disease have string--like pulse due mainly to disorder of cardiac function, lowered arterial compliance and increased total peripheral resistance. The common type of pulse in hematopathy patients is rapid, thready, string--like and slippery, due mainly to increased compensatory pumping action of heart, shortening of ejection time of left ventricle, relatively better vessel compliance and blood rheology as well as low total peripheral resistance.

Adolescent↗