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Biomedical subjects

G Yin

Publications and source records attributed to G Yin.

At least 37 records · Page 2Linked to original sources
PubMed2000

[Studies on gene knocking out of 2-keto aldose reductases from Erwinia sp. SCB125].

Based on the reported gene sequences, the segments containing 2-keto aldose reductase (2-KRA and B) genes were amplified by PCR from the plasmids and Erwinia sp. SCB125 each for gene expression and gene knocking out. Then cloning them into expression vector pBL and successfully expressing them with high enzyme activity in E. coli DH5 alpha. After their enzyme activities were proved, the work on gene knock out followed. Introducing the knock-out vector which distribute unstably during the cell division to the host strains Erwinia sp. SCB125. Screening firstly by the positive marker, one resistance which resulted from the expression of the resistance gene inserting inside the reductase genes and the negative marker, another resistance which outside the reductase genes in the vector. The strains selected out will be tested by further study. This work was the bases of blocking the pathway metabolism and constructing a recombinant strain that can produce 2-KLG directly from D-glucose by one-step fermentation.

Aldehyde Reductase↗
PubMed1999

Intravenous delivery of an endostatin gene complexed in cationic lipid inhibits systemic angiogenesis and tumor growth in murine models.

Inhibition of the neovascularization of tumors has proven efficacious in reducing tumor growth and metastases. Attaining antiangiogenesis through cationic lipid-based systemic gene therapy presents an attractive approach to the treatment of disseminated and primary cancers. Intravenous administration of an endostatin plasmid, complexed with a cationic lipid system, produced significant levels of endostatin in the lung and the circulation. The expressed endostatin blocked systemic angiogenesis and inhibited tumor growth in murine models. Cytokine induction by cationic lipid/DNA complex increased the anti-tumor activities of endostatin. These results demonstrate the possibility of using cationic lipid delivery of an antiangiogenic gene for cancer treatment.

Journal Article↗
PubMed1999

[Histocytopathological study on gastric mucosa of spleen deficiency syndrome].

OBJECTIVE: To explore the pictures of gastric mucosa of Spleen deficiency syndrome, and the relationship between the degree of pathological changes of gastric mucosa and types of Spleen deficiency syndrome. METHODS: One hundred and eighty-eight Spleen deficiency patients with organic diseases of heart, lung, liver, gallbladder, pancreas, intestine and kidney excluded were examined their gastric mucosa. Tests of histopathology and subcellular ultrastructure were conducted by using optical microscope, electron scanning microscope, electron transmission microscope and histochemical staining methods. RESULTS: The gastric mucosa of Spleen Qi deficiency and Spleen Yang deficiency patients could either be affected with organic lesion (type G) or unaffected (type F); the gastric mucosa of Spleen Yin deficiency and Spleen deficiency with Qi stagnation were both affected by gastric lesions, and the degree of their lesions was more serious than that of Spleen Qi deficiency of type G and Spleen Yang deficiency of type G, P < 0.05-0.01. CONCLUSION: Pathological changes did not necessarily occur in the gastric mucosa of Spleen deficiency patients; the degree of pathological changes was relevant with the evolution of Spleen deficiency types.

Adult↗
PubMed1999

Testosterone inhibits apoptosis of Leishmania donovani-infected macrophages.

AIM: Investigate the effect of the male sex hormone, testosterone (Te), on apoptosis of bone marrow derived macrophages (BMMs) from female C57BL/6j mice METHODS: Propidium iodide (PI) staining and transmission electron microscopy (TEM) techniques were used to investigate apoptosis specific-morphological changes. BMMs derived from Te-treated mice and Oil-treated mice were challenged with Leishmania donovani (L. d.), Oligo-nucleosomal DNA were extracted 24 h post infection to detect apoptosis. RESULTS: The removal of M-CSF from the medium could induce BMM apoptofsis. And the DNA fragmentation assay also indicated that: 1. there was no difference in the amount of apoptotic cells between Te and Oil group; 2. Te + L. d. group had significantly less dead cells than Oil + L. d. group demonstrating that Te could prevent apoptosis of macrophage infected with L. d. to a greater extent. CONCLUSION: Te inhibits apoptosis of the macrophages infected with L. d., however, this inhibition did not occur in the macrophages uninfected with L. d. Te-induced macrophage apoptosis-inhibition may play an important role in Te-induced immunosuppression.

Animals↗
PubMed1998

Formation of plasmid DNA strand breaks induced by low-energy ion beam: indication of nuclear stopping effects.

Plasmid pGEM 3zf(+) was irradiated by nitrogen ion beam with energies between 20 and 100 keV and the fluence kept as 1x10(12)ions/cm2. The irradiated plasmid was assayed by neutral electrophoresis and quantified by densitometry. The yields of DNA with single-strand and double-strand breaks first increased then decreased with increasing ion energy. There was a maximal yield value in the range of 20-100 keV. The relationship between DNA double-strand breaks (DSB) cross-section and linear energy transfer (LET) also showed a peak-shaped distribution. To understand the physical process during DNA strand breaks, a Monte Carlo calculation code known as TRIM (Transport of Ions in Matter) was used to simulate energy losses due to nuclear stopping and to electronic stopping. It can be assumed that nuclear stopping plays a more important role in DNA strand breaks than electronic stopping in this energy range. The physical mechanisms of DNA strand breaks induced by a low-energy ion beam are also discussed.

DNA Damage↗
PubMed1998

[Study on multidrug resistant gene (MDR1) expression between neoplastic cells and peripheral blood lymphocytes in ovarian carcinoma].

OBJECTIVE: To explore the correlation of MDR1 (P-glycoprotein, P170) gene expression P170 contents among neoplastic tissues, peripheral blood lymphocytes (PBL) and ascites cancerous cells (ACC) during chemotherapy. METHODS: Content of P170 in cancer tissue, ACC and PBL was quantiated dynamicly by using flow cytometric-immunologic method in 48 cases suffered from ovarian carcinoma. RESULTS: Cancer tissue showed positive P170 in 25% of patients. During chemotherapy, P170 content in PBL and ACC were statistically increased. A significant correlation of P170 was found between PBL and ACC (0.01 < P < 0.05). CONCLUSION: The results indicated that multidrug resistance was produced gradually during chemotherapy. Content of P170 in PBL could probably be used as an indirect index of multidrug resistance for recurrent carcinoma or residual tumor.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

[Immune modulatory and therapeutic effect of lentinan on condyloma acuminatum].

OBJECTIVE: To observe the immune modulatory and therapeutic effect of lentinan on condyloma acuminatum (CA). METHODS: Thirty-six CA patients were randomly divided into two groups, 19 in the test group treated with lentinan plus CO2 laser irradiation and 17 in the control group treated with laser irradiation alone. Their T-lymphocyte subsets of peripheral blood and level of serum interleukin-2 (IL-2) and soluable interleukin-2 receptor (SIL-2R) were determined before and after treatment, and the recurrence rates of the two groups were compared. RESULTS: After treatment, in the test group, the CD4/CD8 ratio, serum IL-2 raised and serum SIL-2R lowered significantly (P < 0.05, 0.05, 0.05 respectively) as compared with before treatment, while those parameters were not changed significantly in the control group. The recurrence rate of the test group was lower than that of the control group, P < 0.05. CONCLUSION: Lentinan could modulate the cellular immunofunction of CA patients and reduce the recurrence rate of CA.

Adjuvants, Immunologic↗
PubMed1998

Effect of testosterone on Leishmania donovani infection levels of murine bone marrow derived-macrophages.

AIM: To investigate the effect of the male sex hormone, testosterone (Te), on Leishmania donovani infection levels of bone marrow derived macrophages(BMMs) from female mice of strain C57BL/6J. METHODS: After three weeks of Te-treatment, the BMMs were isolated, challenged with L. donovani at a ratio of 10 to 1 promastigotes per macrophage, and the infection levels of different time points were monitored by Giemsa staining. RESULTS: BMMs from Te-treated mice had a significantly increased initial uptake(3 h post infection, P < 0.05) of promastigotes and carried heavier infection levels at all time points(24 h, 48 h, 72 h post infection, P < 0.01), compared with those from oil treated controls. CONCLUSION: Te can increase L. donovani infection levels of BMMs, being possibly related to Te-induced immunosuppression.

Animals↗
PubMed1998

[Cloning and expression in E. coli of 2,5-DKG reductase I from Corynebacterium].

Two different 2,5-DKG reductases was purified from Corynebacterium sp. SCB3058, then its genomic DNA was used as template, a segment containing 2,5-DKG reductase I was amplified by PCR and cloned into pGEM3zf(+) to obtain the recombinant plasmid pGEM813. The sequence analysis showed that the cloned segment was 1107 bp in length, contained a single open reading frame of 834 nucleotides, which encoded a 34 kD protein consisted of 278 amino acids. After the primary control sequence was deleted, the expression vector pBL4 was constructed by plasmid pBL. With induction of temperature, a 34 kD protein was specifically expressed in E. coli DH5 alpha in high level. The expressed recombinant protein accounted for 20% of the total cell protein and had high specific enzyme activity. In spite of 30 degrees C, 37 degrees C or 42 degrees C induction, the specific activity of enzyme was almost the same level. These results indicate that most of the recombinant protein induced at 42 degrees C was existed with inclusion bodies. This work was the bases of constructing a recombinant Erwinia which can produce 2-KLG directly from D-glucose by one-step fermentation.

Base Sequence↗
PubMed1997

Exponential heating in drug stability experiment and statistical evaluation of nonisothermal and isothermal prediction.

A new nonisothermal heating model (exponential heating model) for drug stability experiments, based on a theoretical study of simulated nonisothermal data, is presented. In the model, the heating rate dT/dt is increased by 2-4 times at every increase of 10 degrees C in temperature: dT/dt = a(T-T0)/10.(dT/dt)0 where a is the times by which the heating rate is increased at every increase of 10 degrees C. A computation method with optimization and Simpson integration for the experiment was also introduced. The estimates for the shelf-life and activation energy obtained by the exponential and other nonisothermal heating models were statistically evaluated and were compared with those obtained by the isothermal method under various conditions. The results indicated that under the same experimental conditions, the estimates obtained by the exponential heating model were significantly more accurate and precise than those obtained by the linear, reciprocal, and logarithmic heating models. The accuracy and precision of the estimates were independent of the shelf-life of drugs and experimental period. The estimates obtained by the isothermal method were somewhat more accurate and precise than those obtained by the exponential heating model. However, the experimental period needed by the isothermal method was about five times longer than that needed by the exponential heating model. The results also showed that in each of the heating models, the estimates are more accurate and precise by increasing the extent of drug degradation, changing temperature range or sampling frequency, or by having the mean temperature closer to room temperature. To demonstrate its applicability, the exponential heating model was used to study the stability of vitamin C tablets and predict their shelf-life.

Drug Stability↗
PubMed1997

Determination of rate order for degradation of drugs with nonisothermal stability experiment.

The inability of ordinary nonisothermal experiments to determine the rate order (n) of drug degradation is discussed on the basis of a theoretical study of simulated nonisothermal data. In ordinary nonisothermal experiments, using either r or sigma(C[experiment] C[compute])2 as the measure of goodness of fit, the rate order cannot be assessed because the same set of c-t data can be well fitted by different combinations of estimates for n and the activation energy (E). Hence, a new nonisothermal heating-and-cooling model is introduced as a revision, in which sigma(C[experiment] C[compute])2 changes significantly with various kinetic models. Therefore, all the kinetic parameters, including the rate order, can be obtained in one nonisothermal stability experiment. Furthermore, the ability to determine rate order is significantly affected by the extent of drug degradation and experimental error, though not by sampling frequency or temperature change. To demonstrate the applicability of the heating-and-cooling model, the stability and rate order of degradation of vitamin C tablets was studied by this method.

Ascorbic Acid↗
PubMed1997

[Cellular adhesion molecule (CD44) in ovarian tumors].

OBJECTIVE: To investigate a method of detecting adhesion molecule (CD44) contents in ovarian tumors and its clinical significance. METHODS: In 106 patients with ovarian tumors (50 benign and 56 malignant), the adhesion molecule (CD44) contents in peripheral blood lymphocytes (PBL) and in neoplastic tissues were analysed (quantitatively by using flow cytometric-immunological method). RESULT: (1) The CD44 contents in the PBL of the patients with malignant tumor were obviously higher than those of patients with benign tumors (P<0.05) and than those of the control (P < 0.01); (2) Within the group of patients with malignant tumors, the CD44 contents in the neoplastic tissues were higher than those in the PBL (0.01 < P < 0.05); There was no significant difference in CD44 contents among the different histopathological types, whether benign or malignant; (4) The CD44 contents in the PBL decreased gradually after surgery. CONCLUSION: To analyse the CD44 contents in PBL and neoplastic tissues by flow cytometry may be an important method or parameter to differentiate benign ovarian tumors from malignant tumors and to discover recurrence of metastasis of malignant tumors in early stage.

Cell Adhesion Molecules↗
PubMed1997

[Effects of high-dose iodine on brain development in mice].

It is an important topic in medicine and genetics, which has not yet been studied in depth, that whether high-dose iodine, especially iodine excess in mother's body, can cause impediment of brain development in babies as iodine deficiency do. An animal model of goiter was reconstructed in mice with feeding them water containing high level of iodine for three months. Weight of brain, protein and nucleic acid concentrations were measured in one-, seven-, 14-, 21- and 30-day old young mice, and morphological changes in the brain and their abilities of learning and memory were observed in 30-day old young mice, born to mothers with high-iodine goiter. Results indicated that weight of brain, protein content, ratio of protein to DNA, RNA content, and ratio of RNA to DNA all decreased significantly, and DNA content increased in the brain of high-iodine mice, as compared with those in normal iodine mice. Abilities of learning and memory in 30-day old mice decreased. And, those changes began from the seventh to 14th days after their birth. It suggests that excessive intake of iodine, as iodine deficiency, can not only cause high-iodine goiter, but also damage nervous system leading to retardation of brain development and impediment of its function.

Animals↗
PubMed1996

[Experimental studies on effects of excessive iodine intake on morphology and function of kidney in mice].

To understand that if excessive iodine can cause damage to tissues other than thyroid gland, mice were fed with iodine-excess water and iodine-excess goiter was caused in them. Hisitomorphology and function of the kidney, in addition to the thyroid gland, in goiter mice were observed. Results showed that two hundred days after being fed with 3,000 micrograms iodine per liter water, in addition to causing iodine-excess goiter characterized with proliferation of large amount of colloid in thyroid follicles, morphology and function of the kidneys in mice were significantly damaged, with prominent pathomorphological changes of crescent formation and metabolic inhibition in microsome membrane Na(+)-K(+)-ATPase activities in their kidneys. Na(+)-K(+)-ATPase activities were 21.95 +/- 7.50 mumolPi/mg Pr.hr in low iodine group, and 17.64 +/- 8.63 mumolPi/mg Pr.hr in excessive iodine group, with significant difference. It suggests that excessive iodine can cause damage not only to thyroid, but to the whole body.

Animals↗
PubMed1996

[Re-operation of 136 recurrent cases of colorectal cancer].

We analyed 136 recurrent colorectal cancer cases their recurrence, residual cancer foci, extraintestinal infiltration, and inappropriate pelvic resection in patients receiving mile's procedure. The authors suggest that distal safe margin of the colon should at least be more than 3 cm and thorough dissection of the proximal third grade lymphonodes at the upper root of the mesentery and the lateral lymphonodes. For these 136 recurrent cases, after preoperative comprehensive procedure including intraarterial chemoembolization, radiation adjuvant immunotherapy, the resection rate of the recurrent mass was 84.5%. The five year survival rate of palliative resection was 40% as compared with 44.8% in radical resection.

Adenocarcinoma↗
PubMed1995

Construction of a transcription map surrounding the BRCA1 locus of human chromosome 17.

We have used a combination of methods (exon amplification, direct selection, direct screening, evolutionary conservation, island rescue-PCR, and direct sequence analysis) to survey approximately 600 kb of genomic DNA surrounding the BRCA1 gene for transcribed sequences. We have cloned a set of fragments representing at least 26 genes. The DNA sequence of these clones reveals that 5 are previously cloned genes; the precise chromosomal location of 2 was previously unknown, and 3 have been cloned and mapped by others to this interval. Three other genes, including BRCA1 itself, have recently been mapped independently to this region. Sequences from 11 genes are similar but not identical matches to known genes; 5 of these appear to be the human homologues of genes cloned from other species. Another 7 genes have no similarity with known genes. In addition, 39 putative exons and 14 expressed sequence tags have been identified and mapped to individual cosmids. This transcript map provides a detailed description of gene organization for this region of the genome.

Animals↗
PubMed1995

Kinetic study on the photostability of solid vesnarinone and the equivalent relationship between daylight and lamplight.

The photostability of solid vesnarinone on exposure to daylight and lamplight was studied. The equivalent influences of light from different sources on the photostability of solid vesnarinone were observed. Results show that the relationship between the surface reflectance of solid vesnarinone and the cumulative illuminance of light from different sources can be accurately expressed by a curve fit, R = A + B(Et) + C/(Et + D); the daylight can be replaced by lamplight in photostability studies.

Cardiotonic Agents↗