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Biomedical subjects

C Sun

Publications and source records attributed to C Sun.

At least 163 records · Page 9Linked to original sources
PubMed1996

[Protective effects of radix Salviae miltiorrhizae on azathioprine hepatotoxicity in rats].

The changes of liver function and malondialdehyde (MDA) and glutathione (GSH) were studied in rats intoxicated with azathioprine (Aza) 15mg/(kg.d) and in rats treated with Aza mixed Salviae 8g/(kg.d). The results showed that in the Aza group, the levels of ALT, AKP, MDA increased and GSH decreased significantly in week 1 and week 2. But in the Salviae group the levels of ALT, AKP, MDA decreased and GSH increased significantly, approaching the normal levels, It follows that Salviae has protective effects on Aza hepatotoxicity in rats.

Animals↗
PubMed1995

Induction of cisplatinum sensitivity without alteration in radiation sensitivity by fractionated radiation treatment of a human laryngeal squamous cell carcinoma cell line.

PURPOSE: To determine if fractionated radiation treatment can alter cisplatinum sensitivity of a human laryngeal squamous carcinoma cell line. METHODS AND MATERIALS: Human squamous carcinoma cells, both previously untreated, as well as survivors of fractionated radiation therapy, were tested in vitro for their sensitivity to gamma radiation and cisplatinum. Fractionated gamma radiation was delivered in 14 or 10 daily fractions of 2 Gy. The cell line, cSCC-20, was derived from an untreated primary human laryngeal carcinoma. RESULTS: The human laryngeal squamous cell carcinoma cell line, cSCC-20, was demonstrated to have heterogeneous subpopulations with respect to cisplatinum sensitivity. No variation in radiation sensitivity was seen among subpopulations of varying cisplatinum sensitivity. The cells were relatively radioresistant (Do = 2.5 Gy). Fractionated radiation treatments of the parent cell line (14 fractions, 14 days, 2 Gy/fraction) or a cisplatinum sensitive subline (10 fractions, 12 days, 2 Gy/fraction) induced cisplatinum sensitivity (factor of 1.3 to 1.4) in the surviving cells. CONCLUSION: Fractionated radiation treatment of human squamous carcinoma cells in vitro induced sensitivity to cisplatinum without concomitant alteration in radiation sensitivity.

Carcinoma, Squamous Cell↗
PubMed1995

Late mitosis/early G1 phase and mid-G1 phase are not hypersensitive cell cycle phases for neoplastic transformation of HeLa x skin fibroblast human hybrid cells induced by fission-spectrum neutrons.

A two- to threefold increase in the rate of neoplastic transformation in cells irradiated at a dose rate of 0.22 cGy/min with fission-spectrum neutrons compared to that at 10.7 cGy/min has been confirmed with the use of alkaline phosphatase chromogenic substrate Western Blue staining to detect foci of neoplastically transformed cells through their expression of a tumor-associated antigen, the end point of the HeLa x skin fibroblast human hybrid cell transformation assay. To investigate whether the inverse dose-rate effect is due to the existence of a period in the cell cycle in which cells are significantly more sensitive to neoplastic transformation than in the rest of the cell cycle, as has been postulated previously (Rossi and Kellerer, Int. J. Radiat. Biol. 50, 353-361, 1986; Brenner and Hall, Int. J. Radiat. Biol. 58, 745-758, 1990; Elkind, Int. J. Radiat. Biol. 59, 1467-1475, 1991), we compared the sensitivity of late mitotic/early G1-phase and mid-G1-phase cells with that of asynchronous cells. The rationale for examining these particular cell cycle phases was based on the fact that mitosis has been hypothesized to be a candidate for the extremely sensitive period, and on a preliminary report that mid-G1-phase C3H 10T1/2 cells may exhibit enhanced sensitivity for neutron-induced transformation. A nominal dose of 45 cGy of fission-spectrum neutrons was delivered at approximately 10 cGy/min. The data indicate that neither late mitotic/early G1-phase nor mid-G1-phase cells are significantly more sensitive than asynchronous cells. Further, the dependence on the phase of the cell cycle for neoplastic transformation of CGL1 cells induced by fission-spectrum neutrons is different from that previously demonstrated for gamma radiation, where late-mitotic cells were approximately five times more sensitive than mid-G1-phase and asynchronous cells (Redpath and Sun, Radiat. Res. 121, 206-211, 1990).

Cell Cycle↗
PubMed1995

[Mutagenicity of tyramine extracted from salted dried fish in high-risk area of gastric cancer in Zhuanghe county].

Content of tyramine was determined in salted and dried small fish collected from high-risk area of gastric cancer in Zhuanghe County, Liaoning Province with high pressure liquid chromatography, and its mutagenicity after nitrosification was assayed. Results showed content of tyramine in the fish correlated significantly with its mutagenicity (r = 0.993, and P < 0.01). And, tyramine extracted from the fish was verified by thin layer chromatography.

Animals↗
PubMed1995

Factors affecting removal and prognosis of thymic tumors.

One hundred and ten cases of thymic tumors were intervened surgically, including 92 thymoma, 8 thymic carcinoid, and 10 thymic carcinoma. In this series, 50.9% of the cases were complicated with various syndromes, 44.5% with myasthenia gravis (MG). Resection rate was correlated with the size and invasion of the tumor. There was significant difference in resection rate among thymoma, thymic carcinoid and thymic carcinoma. The degree of invasion undoubtedly influenced on resection. The 3-, 5- and 10- year survival rate of the thymoma were 82.7%, 68.1% and 40.0%, respectively. The prognosis depended on the pathological classification and the severity of the neighbouring invasion, but MG had no significant effect on prognosis. Recurrence and metastasis of the tumor were the main cause of late death.

Adult↗
PubMed1995

[Production and characterization of specific monoclonal antibody against Porphyromonas endodontalis].

Porphyromonas endodontalis was known to be important microorganisms in the etiology of pulp and apical infection. In this paper, we generated hybridomas secreting monoclonal antibody against Porphyromonas endodontalis ATCC 35406. The specificity of the monoclonal antibody was examined by ELISA against a battery organisms (109 Strains). The results indicated that the monoclonal antibody did not react with any non-Porphy romanas endodontalis (104 Strains). So our monoclonal antibody is specific for Porphyromanas endodontalis and can be used in clinical samples for detection of pulp and apical infections.

Animals↗
PubMed1994

A mannose-specific lectin from Vicia villosa seeds.

A lectin specific to mannose has been purified from Vicia villosa seed by (NH4)2SO4 fractionation, GalNAc-Sepharose and Man-Sepharose affinity chromatography. It was defined as VVLM, which showed a single band on an acidic-PAGE stained with Coomassie brilliant blue. The molecular weight of VVLM was 50 kDa as determined by gel filtration on Biogel P-100 column. The VVLM molecule consists of 2 distinct subunits with apparent molecular weight of 30 kDa and 22 kDa determined by SDS-PAGE. VVLM has at least four isolectins with similar haemagglutinating activity. Its extinction coefficient is calculated as A1(1cm) = 16.4 at 280 nm. Sugars could not be detected by phenol-sulfuric acid method. The circular dichroism analysis at far UV indicated that VVLM was a beta-sheet-rich protein, and gave no alpha-helix, 69% beta-sheet, 14% beta-turn by Provencher and Glockner method. The lectin was inhibited by alpha-methyl-D-mannose at 12.5 mM and glucose or GlcNAc at 50 mM. The carbohydrate binding specificity of VVLM was investigated by using affinity chromatography on a VVLM-Sepharose column. Among various Asn-linked oligosaccharides, core structure Man alpha 1-->3(Man alpha 1-->6)Man beta 1-->4GlcNAc beta 1-->4GlcNAcOT were found to have high affinity for VVLM-Sepharose. The antisera of VVLM did not produce precipitin line with VVLG in agar double diffusion plate indicating no serological relationship between VVLM and VVLG. However VVLM showed similar immunodeterminants of some other lectins of mannose specificity such as Con A, PSL, LCA and VFL.

Amino Acids↗
PubMed1994

The yeast NOP4 gene product is an essential nucleolar protein required for pre-rRNA processing and accumulation of 60S ribosomal subunits.

The Saccharomyces cerevisiae NOP4 gene was isolated by screening a lambda gt11 yeast genomic DNA library with a monoclonal antibody against a yeast nucleolar protein. NOP4 encodes a 78 kDa protein that contains two prototypical RNA recognition motifs (RRMs) flanking an imperfect RRM lacking characteristic RNP1 and RNP2 motifs. In addition, there is a fourth incomplete RRM. NOP4 is a single copy essential gene present on chromosome XVI, between RAD1 and PEP4. To examine the function of Nop4p, we constructed a conditional null allele of NOP4 by placing this gene under the control of the glucose-repressible GAL1 promoter. When cells are shifted from galactose-containing medium to glucose-containing medium, NOP4 transcription is terminated, Nop4 protein is depleted and cell growth is impaired. Nop4 protein depletion results in diminished accumulation of 60S ribosomal subunits, assignable to a defect in ribosome biogenesis arising from a lack of production of mature 25S rRNA from 27S precursor rRNA.

Alleles↗
PubMed1994

Hemorrhagic fever with renal syndrome: relationship between pathogenesis and cellular immunity.

After phenotype analysis of peripheral blood mononuclear cells (PBMC), soluble interleukin-2 receptor (sIL-2R) levels in plasma or sera from patients with hemorrhagic fever with renal syndrome (HFRS) were measured. The results showed the ratio of activated antigen (CD25, TLiSA1, CD71, and Ia)-positive lymphocytes of PBMC in the acute phase of HFRS was higher than that in convalescent phase. Moreover, there was much higher expression of heteromorphologic lymphocytes than of small lymphocytes. Decreases in T lymphocytes and CD4:CD8 ratios were seen with increases in B lymphocyte ratios and interferon-gamma (IFN-gamma) expression on PBMC surfaces in the acute phase of HFRS. IFN-gamma-positive lymphocytes included CD4, CD8, and CD56 subsets. sIL-2R levels were much higher in sera and plasma in the acute phase, especially the oliguric phase. These findings suggest that patients with HFRS are in a state of high-level cellular immune response, which may be involved in the development of inflammation and pathologic lesions.

Acute Disease↗
PubMed1994

A clinical analysis of 38 patients with primary tracheo bronchial tumors.

During a 17-year period, 38 patients with primary tracheobronchial tumors received surgical treatment in PUMC Hospital. Among the 38, 12 had low-malignancy tracheal tumors, 11 had benign tracheal tumors, 14 had low malignancy bronchial tumors and 1 had a benign bronchial tumor. Fifteen operations were performed on 12 patients with low-malignancy tracheal tumors, including local resection of the tumor and tracheal wall in 4 and curettage of the tumor plus electrical cauterization in 10. Postoperative radiotherapy was used as an adjuvant treatment in 8 patients with adenocystic carcinoma. Eight patients have survived for more than 5 years and 3 patients have survived for longer than 10 years postoperatively. All 11 patients with benign tumors received curettage of the tumor and were followed up for an average of 6.5 years. Among them, 9 are still alive. Of the 14 patients with low malignancy bronchial tumors, 5 underwent curettage of the tumor plus electrical cauterization through incision of the main bronchus or intermedial bronchus, and 7 underwent lobectomy or pneumonectomy. The authors conclude that the correct diagnosis rate can be increased by enhancing recognition of this disease and applying tracheal tomography and bronchoscopy.

Adolescent↗
PubMed1994

[The clinical characters and treatment of lung cancer in youth].

From January 1970 to December 1990, 67 patients with lung cancer aged younger than 40 years, were treated in the PUMC Hospital. There were 43.3% with SCLC and 37.3% with adenocarcinoma. Twenty-eight patients underwent resection of the lung. Thirty-five cases received chemotherapy or radiotherapy only. The clinical and pathological characteristics of lung cancer in youth, and the influence of surgical and non=surgical treatments to the patients with lung cancer are discussed. The authors consider that the bronchoscopic and sputum smear examinations are very helpful for diagnosing lung cancer in the early stage. Postoperative adjuvant chemo- and radio-therapy is suggested because of the high incidence of SCLC and adenocarcinoma in the young patients with lung cancer.

Adenocarcinoma↗
PubMed1994

[Study on size distribution of 8 polycylic aromatic hydrocarbons in airborne suspended particulates indoor and outdoor].

During Jan. 20-27, 1992, the size distribution of 8 polycyclic aromatic hydrocarbons (PAHs) in airborne suspended particulates in Tokyo, Japan was studied. The results showed that PAHs, 79.0%-94.5% in indoor air and 65.4%-90.4% in outdoor air, were associated with aerodynamic diameter less than 2.5 microns particles. The contents of these PAHs in indoor air were: pyrene (Py) 1.98, benzo (a) anthracene (BaA) 0.92, benzo (k) fluoranthene (BkF) 0.91, benzo (a) pyrene (BaP) 2.13, dibenzo (a,h) anthracene (dBahA) 0.30, benzo (b) chrysene (BbC) 0.15, benzo (g,h,i) perylene (BghiP) 2.56, dibenzo (a,e) pyrene (dBaeP) 0.23 ng/m3 and in outdoor air 3.93, 2.01, 1.41, 2.91, 0.40, 0.19, 3.65 and 0.30 ng/m3 respectively. The indoor/outdoor ratios for these PAHs ranged from 0.46 to 0.79. These PAHs contents were significantly correlative with one another and so were between the PAHs contents and the concentrations of airborne particulates both indoor and outdoor (the correlation coefficients ranged from 0.774 to 0.999). The PAHs contents (excluding Py) and the concentrations of airborne particulates between outdoor and indoor samples also correlated well with each other (correlation coefficients ranged from 0.821 to 0.944).

Air Pollutants↗
PubMed1994

[A study of DNA damage induced by asbestos fibers in vitro].

The results of our in vitro study showed that Rhodesia chrysotile, X. K. chrysotile, UICC chrysotile, crocidolite and amosite could cause damage to calf thymus DNA by inducing the production of 8-hydroxy-2'-deoxyguanosine (8-OH-dG). After adding H2O2 and/or FeSO4, the production of 8-OH-dG, induced by asbestos fibers was significantly increased. The fiber of UICC crocidolite has the most untoward effect, that of UICC amosite comes next, and the three chrysotile fibers are the weakest ones. The effect of asbestos fibers on the production of 8-OH-dG has some relationship with hydroxy free radical and the type of asbestos. It is suggested that asbestos fibers could induce DNA point mutation through A.T and G.C transversion by the production of 8-OH-dG, which is related with the carcinogenesis of asbestos.

8-Hydroxy-2'-Deoxyguanosine↗