Biomedical subjects

H Gao

Publications and source records attributed to H Gao.

At least 109 records · Page 6Linked to original sources

PubMed2000

[Detection of epidermal growth factor receptor gene amplification in human laryngeal carcinomas by means of fluorescence in situ hybridization].

OBJECTIVE: To detect epidermal growth factor receptor(EGFR) gene amplification in human laryngeal carcinoma Hep-2 cell line and laryngeal carcinoma tissues. METHODS: The technique of fluorescence in situ hybridization(FISH). RESULTS: The EGFR gene amplification of a laryngeal carcinoma Hep-2 cell line and 5 laryngeal carcinoma tissues were detected by FISH. In the metaphase chromosome and interphase nuclei of Hep-2 cell line and 2 laryngeal carcinoma tissues, distinct cluster and multiple dot signals were found. In the interphase nuclei of the other 3 laryngeal carcinoma tissues, no increase in the number or extent of the hybrid signals was found. CONCLUSION: Compared with normal diploid cell, the EGFR gene amplification was observed at different levels ranging from 2 to 8 folds in metaphase chromosome and interphase nuclei of Hep-2 cell line and 2 laryngeal carcinoma tissues while no amplification was observed in the other 3 laryngeal carcinoma tissues. The results demonstrate that quantitative detection of amplified gene by FISH in the metaphase chromosome and interphase nuclei is useful for detection of laryngeal carcinoma tissues.

ErbB Receptors↗

PubMed2000

A clinical investigation on zhi ling tang for treatment of senile dementia.

Zhi Ling Tang (ZLT [symbol: see text], a TCM prescription designed for replenishing essence, supplementing marrow, invigorating qi, warming yang, removing blood stasis and phlegm, tonifying the brain, and invigorating mental activity) was used in 32 cases of senile dementia (SD). After treatment, the levels of serum cholesterol (Tch), triglyceride (TG), and plasma lipid peroxides (LPO) were lowered; the content of high density lipoprotein (HDL) and the activity of superoxide dismutase (SOD) in RBC significantly elevated, the cerebral blood flow was increased; latent period of P300 and P3 waves was shortened while the amplitude of P3 elevated; and topographic electroencephalogram, revised Hasegawa dementia scales (HDS) scores (P < 0.05-0.01) and clinical symptoms were improved. The total effective rate was 81.3%, indicating that ZLT exhibits relatively good therapeutic effects for treating senile dementia.

Aged↗

PubMed2000

Clinical observation on treatment of non-parvicellular carcinoma of the lung with jin fu kang oral liquid.

Jin Fu Kang Oral Liquid ([symbol: see text]), made of traditional Chinese drugs for supplementing qi and nourishing yin, was developed according to the common symptoms in lung carcinoma with deficiency of both qi and yin. Of the 96 cases in the Jin Fu Kang group, 1 case got complete remission (CR) after treatment, 8 cases partial remission (PR), 52 cases no change (NC), PR + NC covering 63.5%. Of the 52 cases in the group of Jin Fu Kang plus chemotherapy, 11 cases got PR after treatment, 26 cases NC, PR + NC covering 71.2%. Of the 25 cases in the chemotherapy group, 4 cases got PR after treatment, 11 cases NC, PR + NC covering 60.0%. The results show that the therapeutic effectiveness in the Jin Fu Kang group and the group of Jin Fu Kang plus chemotherapy was better than that in the chemotherapy group. The one-year survival rate and the two-year survival rate after treatment in the Jin Fu Kang group were 67.3% and 67.3% respectively; 66.7% and 66.7% in the group of Jin Fu Kang plus chemotherapy; and 40.3% and 0.0% in the chemotherapy group. The improvement of clinical symptoms, increase of body weight and improvement of health situation (KPS marks) after treatment in both the Jin Fu Kang group and the group of Jin Fu Kang plus chemotherapy were better than that in the chemotherapy group. Some indicators of immunology and hemogram after treatment were greatly improved in the Jin Fu Kang group, worse in the chemotherapy group, but no obvious improvement in the group of Jin Fu Kang plus chemotherapy.

Adenocarcinoma↗

PubMed2000

[Construction and nucleotide sequence assay of human anti-HBs variable region single-chain antibody gene].

The VH and Vk gene which were acquired using phage display technology have been combined by a linker encoding a flexible peptide (Gly4 Ser)3 to form a single-chain. Its nucleotide sequence was assayed after cloning the scFv gene into middle plasmid. The successful construction of single-chain gene lays the foundations for the subsequent expression and production of double functional antibody.

Amino Acid Sequence↗

PubMed2000

[Mixing of Cunninghamia lanceolata with Michelia macclurei and restoration of self-sustaining mechanism in G. lanceolata plantation].

The formation of self-sustaining mechanism is one of the major objectives for the sustainable management of plantations. In this study, the incorporation of different proportions of native Michelia macclurei into Cunninghamia lanceolata plantation was practiced to restore the degraded C. lanceolata plantation, and the comparison of nutrient cycling characteristics and soil nutrient concentrations was made among four types of plantation stand with different mixed rate of native M. macclurei representing four different restoration stages of degraded C. lanceolata plantations. With the increase of the proportion of M. macclurei in the plantation, the litterfall and returned nutrients N, P, K, Ca and Mg increased. The nutrient cycling efficiency increased significantly, e.g., that of N and Mg increased from about 0.1 for the degraded pure C. lanceolata plantation to above 0.5 for the pure M. macclurei plantation. Soil organic matter and nutrients also elevated. It is suggested that the self-sustaining mechanism of the C. lanceolata plantation forest gradually reformed as the proportion of native M. macclurei mixed in the plantation increased. The criteria to determine the proportion of native broad-leaved tree species mixed in C. lanceolata plantations for the purpose of sustainable management should be based on whether the self-sustaining mechanism was reformed and whether the soil nutrient status was improved.

Biomass↗

PubMed2000

[Decomposition process of Chinese fir stump roots and changes of nutrient concentration].

With space as a substitute for time, the changes of the density of stump sapwoods and heartwoods, and the releasing process of major nutrients during the decomposition of Chinese fir stump roots were investigated. The yearly loss rate of the densities of sapwoods and heartwoods was 2.767 x 10(-2) and 2.255 x 10(-2) respectively during decomposition. The contents of N and P in sapwoods and roots decreased continually, while those in heartwoods increased during the first stage of decomposition, and then decreased. The K concentration in stump roots decreased remarkably during first two years, and the content of organic substances decreased during the whole decomposition process. The N, P and K concentrations in roots, were higher than those in stump sapwoods and heartwoods at the beginning of decomposition, but bet content of organic substance was opposite.

Abies↗

PubMed2000

[Bioproductivity of Castanopsis hysrix-Cyclobalanopsis glauca-Machilus pauhoi community in Huitong, Hunan].

Based on the mean DBH measurements of sample trees, the bioproductivity of subtropical Castanopsis hysrix-Cyclobalanopsis glauca-Machilus pauhoi community in Huitong, Hunan province was studied by regression analysis (y = a(D2.H)b). The results showed that the total biomass of the forest was 451.02 t.hm-2, and the component biomass of tree, shrub, liana and litter layer was 426.76, 17.76, 1.80 and 4.70 t.hm-2, respectively. The net production and average production of tree layer were 34.46 and 13.32 t.hm-2.yr-1, respectively.

Biomass↗

PubMed2000

[Nutrient retranslocation in fine roots of Cunninghamia lanceolata, Alnus cremastogyne and Kalopanax septemlobum in the mixed plantations--a pilot study].

Comparison of N, P and K concentrations in live and dead fine roots of Cunninghamia lanceolata, Alnus cremastogyne and Kalopanax septemlobum showed that the fine roots of A. cremastogyne had a stronger ability of N retranslocation than K. septemlobum's, but no N translocation occurred in C. lanceolata's. P retranslocation could be found in the fine roots of the all test tree species except C. lanceolata. As for K, it could translocate from fine roots to tree bodies of all these tree species before senescence. Based on the analysis on the difference of N, P, and K concentrations in live fine roots of each pair of tree species in the mixtures, it was suggested that N and K could respectively transfer from the root system of A. cremastogyne and K. septemlobum to the fine roots of C. lanceolata, and the mechanism could be clarified through exploring the ecological process of root-soil interface.

Biological Transport↗

PubMed2000

[Mutation of human O6-alkylguanine-DNA alkyltransferase confers resistance to O6-benzylguanine].

OBJECTIVE: O6-alkylguanine-DNA alkyltransferase (O6-AGT), capable of repairing DNA damage, is responsible for tumor cell resistance to nitrosourea. While O6-benzylguanine as a selective inhibitor of AGT helps reverse drug resistance, it would aggravate myelo-suppression. This investigation is to generate AGT mutant and see if it would confer resistance to O6-benzylguanine-induced inhibition but leave its alkyltransferase activity intact. METHODS: Human O6-methylguanine-DNA methyltransferase (MGMT) cDNA was mutated by site-directed mutagenesis. The mutant cDNA was transferred into E. coli and the protein expressed was purified. The activity of the mutant MGMT was determined in vitro with O6-(3H)-methylguanine-DNA as substrate. RESULTS: Two mutant MGMT proteins were obtained: G156A and P140A, with glycine-to-alanine mutation at position 156 and proline-to-alanine mutation at position 140, respectively. The AGT activity of both mutants was similar to that of the wild type MGMT. However, their resistance to O6-benzylguanine was significantly increased up to 105.8 and 13.5 fold, respectively as compared to that of the wild type MGMT. CONCLUSION: The results suggested that transduction of the mutant MGMT herein reported into hematopoietic progenitor cells may lead to their selective resistance to the combined use of O6-benzylguanine and alkylating agents designed to overcome tumor resistance to nitrosourea treatment.

Amino Acid Sequence↗

PubMed2000

[Effects of nitrogen feeding on the accumulation of poly-beta-hydroxybutyrate with Alcaligenes eutrophus].

On the basis of analysis of PHB fermentation processes, the effects of ammonium sulfate feeding rate at PHB formation period on the PHB accumulation by Alcaligenes eutrophus were investigated. It was shown that the complete absence of nitrogen source at PHB formation phase would lead to the decline of PHB synthetic activity, and the obvious influences of different nitrogen feeding rate on PHB synthesis were observed. Higher PHB content, but relative lower cell dry weight, PHB concentration and PHB productivity could be obtained at slower nitrogen feeding rate. The excessive nitrogen feeding rate resulted in the drop of PHB content, which led to the decrease of PHB concentration and PHB productivity. The better results could be achieved when the ammonium sulfate feeding rate was set at around 0.5 g/h.

Ammonium Sulfate↗

PubMed2000

[Studies on the Robertsonian translocation of Microtus mandarinus].

The type of chromosome No. 1 and chromosome number from 53 individuals of Microtus mandarinus have been studied and compared in three sex types: XY, XX, XO. We found that the first pair of autosomes are very unstable, and there are three types: (1) M, M (With a double metacentric chromosome), (2) M, T, T, (With single metacentric chromosome). (3) T, T, T, T (Without metacentric chromosome). The chromosome number of the same sex individuals changes regularly with the type change of chromosome No. 1, that is, the increase of one chromosome in 2n number is always accompanied by the increase of two T and the decrease of one M, and vice versa. The synaptonemal complexes (SCs) of spermatocyte in pachytene nuclei from the males (2n = 51) were analysed by the electron microscopy. The SCs studies demonstrate that there are 23 fully paired autosomal bivalents, XY-bivalent and an autosomal trivalent. This trivalent is formed by one metacentric and two telocentric elements and characterized by the presence of two short side-arms. Meanwhile, all trivalents are in a cis configuration. The study of G-banding also demonstrates that the No. 1 autosome polymorphism is caused by Robertsonian translocation. Robertsonian fission is the main reason of the polymorphism of chromosome No. 1 and of variation of chromosome number in M. mandarinus.

Animals↗

PubMed2000

[Reconstruction for posterior wall of external meatus and sound transmission apparatus after radical mastoidectomy].

OBJECTIVE: To reconstruct middle ear structure for open mastoid antrum with external auditory canal after radical mastoidectomy in one-stage. METHOD: 71 ears of post-mastoidectomy (discharging 53 ears and dried up 18 ears) were undergone with reconstruction of middle ear. The posterior wall of external auditory canal, mastoid cavity and chain of ossicles were reconstructed with homologous costal cartilage. RESULT: 69 ears of 71 cases were near normal structure followed up 6 months to 5 years after operations. The result showed hearing improvement over 15 dB were 55 ears (77.5%) and under 15 dB were 11 cases (15.5%). Five cases (7.0%) were failed. CONCLUSION: Reconstruction of middle ear with homologous costal cartilage is a ideal surgery to reconstruct hearing structure and avoid infection of middle cavity after radical mastoidectomy.

Adult↗

PubMed2000

[An automotic dialyser reuse device].

This article introduces an automatic dialyser reuse device used to rinse and disinfect dialysers. The Forcing signal generated by automatic program controller is fed into an output circuit and amplified to operate the execute device to realize the mechanical operation for treating the dialyser and the blood lines according to the program. This automatic dialyser reuse operation devices is able to replace the manual operation completely and enhances the reuse operation performance.

Automation↗

PubMed2000

[The study of p16 gene mutation and methylation in laryngeal squamous cell carcinoma].

OBJECTIVE: To investigate the development and mechanism of the p16 gene inactivation in laryngeal squamous cell carcinoma (LSCC). METHODS: With PCR-based methylation assay and PCR-SSCP, first and second exon mutation in p16 gene and methylation of endogenase in promoter in 32 cases of LSCC and paracancer tissue were studied. RESULTS: No mutation were found in first and second exon in the samples; methylation of Cfo I were detected in 6 cases in first exon, methylation of Sac II was found in 4 cases, and methylation of Hpa II in 4 cases. In second exon, methylation of Hpa II was detected in 5 cases and methylation of Cfo I in 6 cases. CONCLUSION: Methylation of promoter in p16 gene is one of the important mechanisms of the inactivation of the gene. The inactivation of p16 gene has a close relation with the development and progress of LSCC.

Carcinoma, Squamous Cell↗

PubMed2000

[Fluorescence quenching method for the determination of trace copper with DBH-PF].

A fluorescence quenching method for the determination of trace Cu(II) was developed. The method was based on the fluorescence quenching effect of DBH-PF and Triton X-100 due to the formation of a non-fluorescent ternary complex in pH 6.2-8.2 KH2PO4-Na2HPO4 medium. The excitation and emission wavelengths are 530 and 560 nm, respectively. The linear range is 0-80 micrograms.L-1 and the detection limit is 0.20 microgram.L-1 for Cu(II). The method has been used to determine trace amounts of Cu(II) in hair, tea and water. The recovery is 98%-104%, and the relative standard deviation is less than 6.9% with satisfactory results.

Copper↗

PubMed2000

[Application of UV spectrophotometry in the detection of magnetization effect].

Compared the UV absorption spectra of some magnetized samples with them of unmagnetized samples(the pure solvents and unmagnetized solutions as the reference substances separately), we found the wavelength of absorption didn't change, but strength of absorption of all magnetized compounds changed. When unmagnetized solutions is selected as reference substances, there may be a peak of magnetic effect in UV absorption spectra. Furthermore, the different magnetization time made the absorbance change in varying degrees. This research will play an important role for the study of possible mechanism of magnetic field effect on chemical reaction.

Magnetics↗

PubMed1999

Participation of the Fas-signaling system in the initiation of germ cell apoptosis in young rat testes after exposure to mono-(2-ethylhexyl) phthalate.

The Fas-signaling system is composed of the interacting proteins Fas (CD95/APO-1) and Fas ligand (FasL, CD95L, APO-1L) and is proposed to act in the testis as a paracrine signaling mechanism by which FasL-expressing Sertoli cells initiate apoptosis of Fas-bearing germ cells. Here we describe alterations in the expression of Fas and FasL in the testis after the intimate physical association between Sertoli cells and germ cells is disrupted by exposure to the Sertoli cell toxicant mono-2-(ethylhexyl) phthalate (MEHP). Young, 28-day-old Fisher rats were treated with MEHP (2 g/kg po) and killed 0, 3, 6, and 12 h after exposure. Immunohistochemical analyses revealed a significant increase in the numbers of Fas-positive germ cells as well as increases in the expression of Sertoli cell FasL. Western blot analysis demonstrated a time-dependent increase in the production of the soluble form of FasL after MEHP exposure and suggests that it may participate in triggering apoptosis in germ cells that have lost their intimate association with the Sertoli cells. Measurement of Fas in cytosolic and membrane fractions of testis homogenates by Western blot analysis revealed a significant shift of Fas expression into the membrane fraction after MEHP exposure. Taken together, these observations indicate that the Fas-mediated paracrine signaling mechanism participates in triggering apoptosis of germ cells despite the loss of their close physical association with Sertoli cells. A working model is presented to explain the involvement of the Fas-system in stimulating germ cell apoptosis after MEHP exposure.

Animals↗

PubMed1999

XK469, a selective topoisomerase IIbeta poison.

XK469 (NSC 697887) is a synthetic quinoxaline phenoxypropionic acid derivative that possesses unusual solid tumor selectivity and activity against multidrug-resistant cancer cells. We report here that XK469 and its S(-) and R(+)-isomers induce reversible protein-DNA crosslinks in mammalian cells. Under protein denaturing conditions, the protein-DNA crosslinks are rendered irreversible and stable to DNA banding by CsCl gradient ultracentrifugation. Several lines of evidence indicate that the primary target of XK469 is topoisomerase IIbeta. Preferential targeting of topoisomerase IIbeta may explain the solid tumor selectivity of XK469 and its analogs because solid tumors, unlike leukemias, often have large populations of cells in the G(1)/G(0) phases of the cell cycle in which topoisomerase IIbeta is high whereas topoisomerase IIalpha, the primary target of many leukemia selective drugs, is low.

Animals↗