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Biomedical subjects

H Sun

Publications and source records attributed to H Sun.

At least 235 records · Page 13Linked to original sources
PubMed1999

[Effect of beta-carotene on mouse transplantable mammary cancer MA737].

OBJECTIVE: To study the effect of beta-carotene (BC) on the growth of MA737 in TA II mice. METHODS: BC (250 mg/kg) dissolved in vegetable oil was given per os by gavage once every other day. Mice were treated with BC alone or in combination with chemotherapy (CMF protocol). Control mice were given solvent vehicle. Tumor volume and survival period of the treated and control mice were recorded. RESULTS: In mice treated with BC alone, the growth of the tumor was retarded, but the tumor inhibitory effect was more marked in mice treated with BC + CMF (growth inhibition rate: 49.1% versus 60.5%). The therapeutic effect of combined use of BC and CMF was only slightly better than that of CMF alone. However, BC helped alleviate toxic side effects of the chemotherapeutic drugs so that the survival period was significantly prolonged in the BC + CMF treated mice. Long term treatment with beta-carotene was without side effect. CONCLUSION: beta-carotene inhibits tumor growth, prolongs survival and alleviates toxic side effects of chemotherapy in a mouse mammary cancer model.

Animals↗
PubMed1999

[Expression of C-erbB-2 oncogene mRNA in salivary gland tumors].

OBJECTIVE: To study relationship of C-erb-2 oncogene mRNA expression and histotype, tumorigenesis and biological behavior of salivary gland neoplasms. METHODS: Using 32P labeled oligonucleotide as probe, the dot blot technique was used to study the expression of C-erbB-2 oncogene mRNA in salivary gland neoplasm with normal salivary gland as control. RESULTS: With the expression in normal salivary gland as a standard, low C-erbB-2 mRNA expression was seen in adenolymphoma, basal cell adenoma. However, various degrees of over-expression of C-erbB-2 oncogene mRNA were detected in pleomorphic adenoma, mucoepidermoid carcinoma, acinic cell carcinoma, adenoid cystic carcinoma, papillary cystic carcinoma, and myoethelial cell carcinoma. CONCLUSION: C-erbB-2 oncogene mRNA over-expression in salivary gland neoplasm is related to biological behavior of salivary gland carcinoma.

Adenolymphoma↗
PubMed1999

[Effect of composite blood-activating decoction on expression of adherent molecule and cyclin in bone marrow hematopoietic cells in mice of immune-induced aplastic anemia].

OBJECTIVE: To study the effect of composite blood-activating decoction (CBAD) on expression of adherent molecule CD49 d and cyclin D2 in bone marrow hematopoietic cells in experimental immune-mediated aplastic anemia (AA) mice. METHODS: After the model of AA was established, the animals were fed with 0.2 ml of 100% CBAD, twice a day for 12 days. Te CD49 d and cyclin D2 expression level of bone marrow hematopoietic cells in model mice were measured by flow cytometor analysis system at the 13th day of experiment. RESULTS: CD49 d expression level in CBAD group was significantly higher than that in the AA group (P < 0.05), and was similar to that in the normal group (P > 0.05). The expression of cyclin D2 in CBAD group was significantly higher than that in the AA group (P < 0.01), but the cell count of G0 + G1 phase was significantly lower in the CBAD group, as compared with the AA group, P < 0.01. CONCLUSION: CBAD can increase the expression of adherent molecule CD49 d and cyclin D2 in bone marrow hematopoietic cells, and promote the growth of hematopoietic cells.

Anemia, Aplastic↗
PubMed1999

[Evaluation of atrial natriuretic peptide in differentiating benign and malignant pleural effusion].

OBJECTIVE: To discuss the value of atrial natriuretic peptide (ANP) in differentiating benign and malignant pleural effusion. METHODS: Direct radioimmunoassay was used to detect ANP of pleural effusion and serum in 30 tuberculous and 26 cancerous pleural effusion patients. RESULTS: The ANP in tuberculous and cancerous pleural effusion were (75 +/- 9) ng/L, (157 +/- 45) ng/L respectively, and significant difference was found (P < 0.001). The ANP of tuberculous pleural effusion was apparently lower [(75 +/- 9) ng/L] than serum [(170 +/- 37) ng/L], and significant difference was also found (P < 0.001). The ratio of ANP of pleural effusion to that of serum were 0.47 +/- 0.17, 0.99 +/- 0.46 respectively in tuberculous and cancerous pleural effusion patients. The sensitivity of ANP was 81% and specificity 100% in diagnosing malignant pleural effusion. CONCLUSIONS: Detecting ANP of pleural effusion is one of important methods for differentiating benign and malignant pleural effusion.

Adolescent↗
PubMed1999

[A clinical study on vaccine of Mycobacterium vaccae in treating pulmonary tuberculosis].

OBJECTIVE: To study the effect of vaccine of Mycobacterium vaccae on cell-mediated immunity and on treating patients with pulmonary tuberculosis. METHODS: Seventy cases of pulmonary tuberculosis with smear positive and initial treatment were classified randomly into group I (35 cases) and group II (35 cases), receiving 2HRZS/4HR and 2HRZS/4HR plus vaccine of Mycobacterium vaccae regimens respectively. Thirty-one multi-drug resistant pulmonary tuberculosis cases were classified into group III, receiving 4 - 6 sensitive antituberculous drugs and vaccine of Mycobacterium vaccae. Improvement of clinical symptoms, resolution of pulmonary lesions, negative conversion of sputum and changes of immunological functions were observed. RESULTS: No significant difference in improvement of symptoms was found in group I and group II (P > 0.05), and the improvement rate of clinical symptoms in group III was found more than 50%. X-ray resolution rates in 4th month were 83% and 89%, and cavity reducing rates 40% and 50% respectively in group I and group II, and no significant differences were found (P > 0.05). X-ray resolution rate was 29%, cavity reducing rate 7% and no deteriorated case was found in group III. Sputum negative conversion rates in 1st, 2nd, 3rd and 4th month were 23%, 51%, 83% and 97% respectively in group I, while 31%, 77%, 89% and 100% in group II, and 3%, 16%, 29% and 32% in group III. Significant difference was found between group I and group II in sputum negative conversion rate in 2nd month after treatment (P < 0.05). After treatment, values of lymphocyte transformation test (LTT), CD(3), CD(4) and CD(4)/CD(8) of the above 3 groups were all higher than that before the treatment (P < 0.05), level of tumor necrosis factor decreased in group II and IL-2, IL-6 increased in group III. CONCLUSIONS: Vaccine of Mycobacterium vaccae is a good immunotherapy preparation, which promotes sputum negative conversion and activation of cell-mediated immunity.

Adolescent↗
PubMed1999

[One stage surgical repair for complex cranio-orbital injury].

OBJECTIVE: To approach clinical effect of early stage surgery on complex cranio-orbital injury. METHODS: Surgical procedures included removal of intracranial hematoma, contused and necrotic brain tissues, correction of cranio-orbital deformity, and repair of dure mater. RESULTS: Early evaluation was completed in 6 weeks, and late evaluation was made in 6 months after surgery according to the scale of Jennett and Bond's plastic surgical outcome and Glasgow outcome scale (GOS). Six weeks after surgery, GOS grade I was observed in 6 patients and GOS grade II in 3 patients. Excellent scale of Jennett and Bond was seen in 4 patients and good scale in 3 patients. Cerebrospinal leakage was effectively obstructed in 5 patients. CONCLUSIONS: Early stage repair for complex cranio-orbital injury may be conducive to improving neural function and decreasing intracranial infection.

Adult↗
PubMed1999

[Transpetrosal presigmoid approach for removal of giant petroclival tumors].

OBJECTIVE: To discuss the operative technique, advantage and postoperative complications in 41 patients with giant petroclival tumors treated with the supra- and infratentorial transpetrousal presigmoid approach. METHODS: Clinical data were obtained from the review of charts and radiographic images of the 41 patients after operation with temporo-occipotal free osseous flap, partial petrosectomy and mastoidectomy were performed around the labyrinth. The semicircular canals, cochlea and tympanic cavity were protected during the operation. After the super petrous was ligated and cut off, the petroclival region in front of the sigmoid sinus was exposed. RESULTS: In the 41 patients 20 had meningiomas, 20 epidermoid cysts, and one schwannoma. Total resection was performed in 34 patients, subtotal resection in 16, and greater partial resection in one. Major postoperative complications included temporal aphasia (10 patients), cerebral edema (6), brain stem infarct (2), IIIth, VIIth, VIth and posterial group cranial nerves palsies (16, 16, 8, 6 respectively), and cerebrospinal fluid leakage (4 cases). CONCLUSIONS: This approach can expose sufficiently the petroclival region. It can also reveal the area of adjacent sella, interpeduncular and formen magnum, and homolateral III-XIIth cranial nerves. The postoperative complications may be related to operative techniues and tumorous characteristics.

Adolescent↗
PubMed1999

[Effect of epidermal growth factor on proliferation of lens epithelial cells].

OBJECTIVE: To study the effect of epidermal growth factor (EGF) on lens epithelial cells (LECs). METHODS: Bovine LECs (bLECS) and human LECs (hLECs) in culture were treated with EGF. Then, MTT assay was used to examine the proliferation of the cells and the effect of anti-EGF receptor (EGFR) antibody. RESULTS: BLECs showed marked proliferation depending on the concentration of EGF from 10(-1) - 10(2) microg/L, and EGF at a concentration of 10 microg/L on day 3 induced the highest increase of proliferation; EGF promoted proliferation of hLECs at the concentration of 1 - 10(2) microg/L and EGF of 10(2) microg/L showed the highest promotive effect on proliferation. The anti-EGFR antibody blocked the promotive effect of EGF on proliferation of hLECs when the concentration of this antibody was as low as 0.5 mg/L, and the blocking rate was 81% at the concentration of 3 mg/L. CONCLUSIONS: EGF has a promotive effect on proliferation of LECs. It is suggested that there are specific EGFRs on the surface of hLECs. EGFs bound to their receptors stimulate proliferation of LECs and play an important role in occurrence and development of posterior capsular opacification after cataract surgery.

Adolescent↗
PubMed1999

[Application of derivative technique in the signal processing of gas chromatography].

An application of derivative technique in the signal processing of gas chromatography(GC) is described. TCD's sensitivity of the derivative GC was 270 kV.L/kg, and its susceptibility was 0.3 microgram/L In comparison with the conventional GC, there was a 7-40 fold increase in sensitivity and a 24-40 fold decrease in susceptibility. The noise of the derivative GC was equal to or smaller than the conventional one. The minimum resolution for a pair of substances most difficulty to be separated in conventional GC, which was separated completely in the derivative GC, was 2.8. The linear range of n-butanol was 10(2) and the peak area correlation coefficient of the derivative GC was 0.9991.

1-Butanol↗
PubMed1999

[The T cell activation from peripheral blood of patients with herpetic keratitis following in vitro activation].

OBJECTIVE: To evaluate the T cells activation from peripherial blood(PB) of patients with herpes simplex keratitis following in vitro activation. METHODS: The flow cytometry was used to investigate the expression of HLA-DR, CD25, CD69, CD71 on T cell from PB, the PB in culture, the PB cultured with phytohemagglutinin(PHA) or phorbol 12, 13-dibutyrate(PDB) or PDB and ionophore (IONO), in 7 cases with herpetic stromal keratitis (HSK) and 4 cases with herpetic ulcer keratitis(HUK). 6 normal people were set as control. RESULTS: The percentages of CD3+DR71+ was higher, and the CD3+CD71+ was lower from PB of patients with HSK than those from normal people. After the PB was cultured for 72 hours, the percentages of CD8+CD71+ in lymphocytes from HSK and CD8+DR+, CD8+CD69+, CD8+CD71+ in lymphocytes from HUK were lower than those from nomal people. And the CD8+CD71+ cells from HUK also was lower than those from HSK. When the PB was cultured with PHA for 72 hours, the percentages of CD3+CD71+, CD8+CD69+, CD8+CD71+ from HSK and HUK were lower than those from normal people. The percentages of CD8+CD25+ in lymphocytes from HUK also was lower than those from normal, and the CD8+CD69+ cells in lymphocytes was lower than those from HSK. The percentages of CD3+CD71+ in PB cultured with PDB for 72 hours, CD3+CD69+ in PB cultured with PDB and IONO for 72 hours from HSK were lower than those from normal people. CONCLUSION: The ability of T cells activation decreases in cases with HSK following in vitro activation. The lymphocytes in patients with HUK shows much lower activation than those cases with HUK.

Antigens, CD↗
PubMed1999

[Determination of zinc in vegetable oils by FAAS with trace injection method].

A method for the determination of zinc in the soybean, cottonseed and sesame oils by FAAS with trace injection technique was discribed in this paper. The injection volume was 30 microL. The characteristic concentration and the detection limit were 0.098 and 0.00368 microg/g, respectively. The relative standard deviation was 2.6% and the recoveries were in the range of 92.9%-107.8%. The contents of zinc in the samples were 9.67, 1.42 and 1.77 microg/g, respectively.

Limit of Detection↗
PubMed1999

[Study on laser flash spectroscopy of processes of photoionization of tyrosine: pH effects].

The processes of photoionization of tyrosine on three different pH value solutions were investigated by 248 nm laser flash photolysis. The results showed that the processes of photoionization of tyrosine were affected by pH value of the solution. With pH value increasing, the molecule number of photoionization increases via a monophotonic process, and decreases via a biphotonic process. Furthermore, the pH effect of photoionization of tyrosine resulting from deprotonation of phenolic hydroxyl group in alkaline solution was demonstrated.

Hydrogen-Ion Concentration↗
PubMed1998

PTEN/MMAC1/TEP1 suppresses the tumorigenicity and induces G1 cell cycle arrest in human glioblastoma cells.

PTEN/MMAC1/TEP1 is a tumor suppressor that possesses intrinsic phosphatase activity. Deletions or mutations of its encoding gene are associated with a variety of human cancers. However, very little is known about the molecular mechanisms by which this important tumor suppressor regulates cell growth. Here, we show that PTEN expression potently suppressed the growth and tumorigenicity of human glioblastoma U87MG cells. The growth suppression activity of PTEN was mediated by its ability to block cell cycle progression in the G1 phase. Such an arrest correlated with a significant increase of the cell cycle kinase inhibitor p27(KIP1) and a concomitant decrease in the activities of the G1 cyclin-dependent kinases. PTEN expression also led to the inhibition of Akt/protein kinase B, a serine-threonine kinase activated by the phosphatidylinositol 3-kinase (PI 3-kinase) signaling pathway. In addition, the effect of PTEN on p27(KIP1) and the cell cycle can be mimicked by treatment of U87MG cells with LY294002, a selective inhibitor of PI 3-kinase. Taken together, our studies suggest that the PTEN tumor suppressor modulates G1 cell cycle progression through negatively regulating the PI 3-kinase/Akt signaling pathway, and one critical target of this signaling process is the cyclin-dependent kinase inhibitor p27(KIP1).

Amino Acid Sequence↗
PubMed1998

The protein kinase Pak3 positively regulates Raf-1 activity through phosphorylation of serine 338.

The pathway involving the signalling protein p21Ras propagates a range of extracellular signals from receptors on the cell membrane to the cytoplasm and nucleus. The Ras proteins regulate many effectors, including members of the Raf family of protein kinases. Ras-dependent activation of Raf-1 at the plasma membrane involves phosphorylation events, protein-protein interactions and structural changes. Phosphorylation of serine residues 338 or 339 in the catalytic domain of Raf-1 regulates its activation in response to Ras, Src and epidermal growth factor. Here we show that the p21-activated protein kinase Pak3 phosphorylates Raf-1 on serine 338 in vitro and in vivo. The p21-activated protein kinases are regulated by the Rho-family GTPases Rac and Cdc42. Our results indicate that signal transduction through Raf-1 depends on both Ras and the activation of the Pak pathway. As guanine-nucleotide-exchange activity on Rac can be stimulated by a Ras-dependent phosphatidylinositol-3-OH kinase, a mechanism could exist through which one Ras effector pathway can be influenced by another.

Amino Acid Sequence↗
PubMed1998

Comparison of the mode of action of a dinuclear platinum complex containing a pyridine derivative with its monomeric analog.

The DNA binding and interstrand cross-linking properties of the dinuclear platinum complex [¿cis-Pt(NH3)2Cl¿2bpsu](NO3)2 (bpsu is 4,4'-dipyridyl sulfide) (II) and the mononuclear complex [cis-Pt(NH3)2Cl(4-methylpyridine)]NO3 (I) were compared with those of [¿cis-Pt(NH3)2Cl¿2H2N(CH2)4NH2](NO3)2 (III) in order to understand the mode of action of complexes I and II. Both compound I and compound II caused significantly different changes of conformation in poly(dG-dC) x poly(dG-dC) than compound III did. Studies of DNA binding, interstrand cross-linking and fluorescence assay suggest that compound I monofunctionally binds to DNA and compound II bifunctionally binds to DNA, that the dinuclear platinum complex II more efficiently interacts with DNA compared to its monomeric analog, and that platinum I and II complexes both interact with DNA in a non-intercalative mode. All the results indicate that the mode of action of the dinuclear complex II is different from that of the mononuclear complex I.

Animals↗
PubMed1998

The Bloom's syndrome helicase unwinds G4 DNA.

BLM, the gene that is defective in Bloom's syndrome, encodes a protein homologous to RecQ subfamily helicases that functions as a 3'-5' DNA helicase in vitro. We now report that the BLM helicase can unwind G4 DNA. The BLM G4 DNA unwinding activity is ATP-dependent and requires a short 3' region of single-stranded DNA. Strikingly, G4 DNA is a preferred substrate of the BLM helicase, as measured both by efficiency of unwinding and by competition. These results suggest that G4 DNA may be a natural substrate of BLM in vivo and that the failure to unwind G4 DNA may cause the genomic instability and increased frequency of sister chromatid exchange characteristic of Bloom's syndrome.

Adenosine Triphosphatases↗
PubMed1998

Coordination of Zn2+ (and Cd2+) by prokaryotic metallothionein. Involvement of his-imidazole.

In mammalian metallothionein Zn2+ is exclusively coordinated to Cys-thiolate to form clusters in which the metal is thermodynamically stable but also kinetically labile. By contrast, little is known about coordination to prokaryotic metallothionein, SmtA. 3 nmol of Zn2+ nmol-1 SmtA were displaced by 8 nmol of p-(hydroxymercuri)phenylsulfonate implicating eight of the nine Cys in the coordination of three metal ions. None of the Zn2+ associated with SmtA was accessible to 4-(2-pyridylazo)resorcinol prior to the addition of p-(hydroxymercuri)phenylsulfonate. An unusual feature of SmtA is the presence of three His residues, and we have investigated whether these contribute to metal coordination. Less Zn2+ was associated with purified SmtA(H40R/H49R/H55R), in which all three His residues were substituted with Arg, and approximately one equivalent of Zn2+ was immediately accessible to 4-(2-pyridylazo)resorcinol. Following incubation of SmtA with 111Cd, three 111Cd resonances were detected, two in a range expected for CdS4 and the third indicative of either CdNS3 or CdN2S2 coordination. Two-dimensional TOCSY 1H NMR and 111Cd-edited 1H NMR showed two His residues bound to 111Cd, confirming CdN2S2 coordination. The pH of half-dissociation of Zn2+ increased from 4.05 for SmtA to 5.37 for SmtA(H40R/H49R/H55R). Equivalent values for single His mutants SmtA(H40R), SmtA(H49R), and SmtA(H55R) were 4.62, 4.48, and 3.81, respectively, revealing that conversion of His40 or His49 to Arg impairs Zn2+ binding at the CdN2S2 and CdS4 sites. Only approximately two equivalents of Zn2+ were associated with purified SmtA(H49R). The appearance of a fourth 111Cd resonance at lower pH suggests that an alternative CdN2S2 site also exists.

Amino Acid Sequence↗