Biomedical subjects

G Li

Publications and source records attributed to G Li.

At least 361 records · Page 20Linked to original sources

PubMed2000

[The expression and clinical significance of p80 protein in anaplastic large cell lymphoma].

OBJECTIVE: To investigate the relationship of expression of NPM-ALK cohesive gene protein with the subtypes and prognosis of anaplastic large cell lymphoma (ALCL). METHODS: Nineteen cases of ALCL with CD30 positivity were studied. Immunohistochemical staining was performed in paraffin sections by using polyclonal antibody anti-p80 and other monoclonal antibodies. The clinical data of these patients were analyzed and all patients were followed-up. RESULTS: The neoplastic cells in 9 out of 19 ALCL expressed p80 protein. Histopathologically, all 9 cases with p80 expression were common type and small cell type. None of these 9 cases were Hodgkin like type (P < 0.05). Immunologically, all the 9 positive cases were T and null cell phenotype and none of them was B cell or other phenotype (P < 0.05). Clinically, the patients with p80 expression were younger than those without p80 expression (P < 0.05). The prognosis of the former was worse than in the later (P < 0.05). CONCLUSIONS: p80 positive ALCL could be a new clinicopathological entity. The polyclonal antibody anti-p80 might be an useful marker for the differential diagnosis and prognosis estimation of ALCL.

Adolescent↗

PubMed2000

[Subcutaneous panniculitis-like T-cell lymphoma: expression of cytotoxic-granule-associated protein TIA-1 and its relation with Epstein-Barr virus infection].

OBJECTIVE: To study the clinicopathologic features, the expression of cytotoxic-granule-associated protein TIA-1 and Epstein-Barr virus (EBV) infection in subcutaneous panniculitis-like T-cell lymphoma (SPTCL). METHODS: Totally 17 cases of SPTCL were studied. Immunohistochemical staining was done for TIA-1, CD45RO, CD3, CD20 and CD68, and in situ hybridization for EBV encoded small nuclear RNA (EBER1/2). RESULTS: In the 17 cases of SPTCL, the ratio of male-to-female was 1:1.1 and the median age was 24 years old. The main clinical manifestations were asymptomatic plaques, nodules and masses. Histologically, the pattern of lymphoid cells infiltration was panniculitis. The infiltrated lymphoid cells were pleomorphic and their mitotic figures were few (0 - 2/hpt). In the tumor tissue, there might be epithilioid granulomas, multinuclear cells, beanbag cells, small pieces of necrosis and small vessels with lymphoid cells infiltration in the vascular wall. Immunohistochemically, all the cases showed a T-cell phenotype and the expression rate of TIA-1 was 100% (16/16). By in situ hybridization, the positive rate of EBV-EBER1/2 was 29.4% (5/17). CONCLUSIONS: SPTCL has a specific histopathologic picture. It may originate from cytotoxic T lymphocytes or NK cells. Some of them may be accompanying with EBV latent infection.

Adolescent↗

PubMed2000

[The effects of different patterns of mechanical ventilation on the respiratory mechanics and gas exchange in dogs severely injured by steam inhalation].

OBJECTIVE: To study the effects of conventional mechanical ventilation (CMV), high-frequency jet ventilation (HFJV) and high-frequency bidirectional jet ventilation (HFTJV) on the respiratory mechanics and gas exchange in dogs inflicted severely by steam inhalation injury. METHODS: Nine mongrel dogs inflicted by steam inhalation to severe inhalation injury were served as the model. Indices of respiratory mechanics, hemodynamics and blood gas analysis were monitored respectively with the above three patterns of mechanical ventilation. RESULTS: (1) Total respiratory resistance (Rrs) and resistance of lungs (R(L)) were evidently higher with the ventilations than those in control (P < 0.01). And total respiratory compliance (Crs) and compliance of lungs (C(L)) were obviously lower with the ventilations than those in control (P < 0.05) but with no significant differences among the changes of Rrs, R(L), Crs and C(L). (2) Carbon dioxide (CO(2)) retention could be induced by CMV and HFJV. HFTJV was much more effective than HFJV in enhancing the expiration of CO(2) (P < 0.01). (3) There was no remarkable difference in functional residual capacity (FRC) and PaO2 between dogs with three patterns of ventilations. CONCLUSION: All these three patterns of ventilations could overcome the respiratory resistance and help respiration, but they couldn't restore the high airway resistance and low compliance of lungs already established postburn. The efficiency of CMV was similar to that by HFJV, but that of HFTJV was much better than that of HFJV.

Animals↗

PubMed2000

[Relationship between human herpesvirus 6 infection and idiopathic thrombocytopenic purpura].

OBJECTIVE: To investigate the pathogenic role of human herpesvirus 6 (HHV-6) in idiopathic thrombocytopenic purpura (ITP). METHODS: HHV-6 DNA was examined by polymerase chain reaction (PCR) in bone marrow mononuclear cells (BMMNC) of 105 ITP patients. Human cytomegalovirus (HCMV) and parvovirus B(19) DNA were also examined in some cases. Platelet-associated antibodies (PAIg) were measured by competitive ELISA in 66 ITP patients. Serum IgG titer to HHV-6 was observed by indirect immunofluorescence assay in 19 ITP patients. RESULTS: (1) HHV-6 DNA positivity was 41.0% for ITP patients, significantly higher than that for control group (P < 0.05). HHV-6 DNA positivity for adult ITP patients, especially adult chronic cases was significantly higher than that for childhood patients (P < 0.025). Positivities for parvovirus B(19) and HCMV DNA were 24.1% and 9.7%, respectively. (2) HHV-6 DNA positivity for patients with abnormal level of PAIgG was significantly higher than that for patients with normal level of PAIgG (P < 0.05). (3) Patients coinfected with HHV-6 and B(19) or HCMV had more severe symptoms or poorer prognosis. CONCLUSION: HHV-6 infection might be associated with excessive PAIgG. Coinfection with HHV-6, B(19) or HCMV may cause more severe symptoms in ITP patients.

Adolescent↗

PubMed2000

[Relationship between the changes of serum free fatty acids and insulin resistance in type 2 diabetics].

The purpose of this study was to investigate the changes of serum free fatty acids (FFA) in fasting state and absorptive state and the relationship between FFA changes and insulin resistance in the patients with type 2 diabetes (DM2). 75 g of glucose were given to 60 patients with DM2. Fasting serum FFA, serum insulin levels and the same parameters 2 h after glucose load were measured by calorimetric and RIA methods. Fasting and 2 h after oral glucose tolerance test (OGTT) plasma glucose(PG) levels were also assessed by using glucose oxidase method. The results showed the levels of serum FFA, PG and insulin of fasting and after glucose load in the patients were significantly increased and their insulin-sensitive (ISI) was remarkably decreased as compared with those in 30 normal controls, P < 0.05. Multiple stepwise regression analysis showed that the FFA level of 2 h after OGTT was negatively correlated with ISI, P = 0.0304. The results suggest that in patients with DM2, the levels of fasting and absorptive FFA are significantly elevated, which is negatively correlated with the decline of ISI, implying the association of abnormal fasting and absorptive FFA and insulin resistance in patients with type 2 diabetes.

Adult↗

PubMed2000

[Studies on application for classification and identification in Mycobacterium by analysis of PCR amplification of 16S-23S ribosomal DNA spacer sequences].

The 16S-23S ribosomal DNA spacer sequence of mycobacterium were amplified by PCR. The products were visualized by PAGE, and evaluate the possibility for classification and identification of mycobacterium at gene level. The sensitivity of PCR in annealing temperature 45 degrees C was 500 fg/microL, whereas 50 degrees C was 5 pg/microL. The results showed that: the amplified bands ranging from 300 to 600 bp, most of rapid-growing Mycobacterium and Nonmycobacterium tested have more bands and the bands molecular weights were larger than slow-growing Mycobacterium. The relativity of mycobacterium < 70%, most of them < 50%. This experimental method might be rapid and effective for differentiation of Mycobacterium at species level.

Cluster Analysis↗

PubMed2000

[Studies on detection methods of two DNA probes in Mycobacterium tuberculosis].

Two different biotinylated DNA probes which are highly specific to M. tuberculosis(MT) were made and studied. One probe is a 20 bp oligonucleotide labeled with biotin at 5' end, the other is a long DNA probe produced by PCR amplification procedure allowed for the incorporation of biotin labeled UTP. The two probes were hybridized with MT genome DNA and a 317 bp PCR product amplified from IS6110 sequence of MT, and then detected by alkaline phosphatase conjugates through colorimetric reaction. The detection sensitivity and specificity of the two probes were comparatively studied. The hybridization condition including concentration of probe, temperature of hybridization and washing filter thereafter were also investigated preliminary. The detection limit of the oligonucleotide probe and the 188 bp PCR probe were 100 ng and 6 ng of DNA respectively in detection of M. T genome, and 400 pg and 50 pg of DNA respectively in detection of PCR products of MT. The two probes can be only hybridized to MT and BCG, but not with other 24 mycobacterium or non-mycobacterium tested. The optimal hybridization temperature and washing filter temperature of oligonucleotide were 42 degrees C and 60 degrees C respectively; and that of 188 bp probe, 68 degrees C and 60 degrees C-68 degrees C. Generally the specificity of two probes were all high, but the sensitivity of 188 bp DNA probe was 7-16 times that of the oligonucleotide probe. The higher sensitivity, lower hybridization background and faster revelation of the 188 bp DNA probe made it a better choice in detection of MT.

Biotin↗

PubMed2000

[Differentiation of human glioma cells BT-325 induced by sodium butyrate].

OBJECTIVE: To study the differentiation of human glioma cells BT-325 induced by sodium butyrate in vitro. METHODS: BT-325 cells were treated with 1 mmol/L sodium butyrate. Flow cytometry was used to analyze the cell cycle. Cell differentiation was identified by flow cytometry and Western blot analysis. RESULTS: After 6-8 days of sodium butyrate treatment, the differentiation characters could be observed distinctively, such as the reduced cell density, the increased cell size and the marked increase in cell process formation and cell-to-cell connection. At the same time, Western blot showed that the amount of glial fibrillary acidic protein was elevated after the sodium butyrate treatment. CONCLUSION: Human glioma cells BT-325 could be induced to differentiation by sodium butyrate.

Brain Neoplasms↗

PubMed2000

[The identification and cloning of human ubiquitin binding enzyme cDNA].

OBJECTIVE: To identify and clone the gene encoding human ubiquitin binding enzyme and study its expression spectrum. METHODS: According to the sequence of human EST, which is highly homologous to the mouse ubiquitin conjugating enzyme (E2), primers used for library screening were synthesized to screen the human fetal brain cDNA library. The gene was analyzed by making use of bioinformatics and its expression spectrum was studied by using multiple-tissue Northern blot. RESULTS: Two cDNA clones encoding human ubiquitin conjugating enzyme were isolated and identified. Both containing the ubiquitin conjugating domain, they were 88% identical in amino acid sequences and found to be isoforms of each other with only an exon excised from the short sequence. They belonged to a highly conserved, and widely expressed E2 enzyme family. Northern blot showed that they were expressed exclusively in heart, placenta, and pancreas while no transcripts could be detected in brain, lung, liver, skeletal muscle, or kidney. CONCLUSIONS: The gene encoding human ubiquitin binding enzyme is expressed under both temporal and spatial control. As a key enzyme in the degradation of proteins, ubiquitin conjugating enzymes play a central role in the expression regulation on the level of post-translation.

Amino Acid Sequence↗

PubMed2000

[Transgenic mice model of human hepatitis B virus x gene].

OBJECTIVE: To set up a human hepatitis B virus x (HBx) gene transgenic model. METHODS: The model was set up by microinjection, the integration and expression of the founders were identified by molecular hybridization. RESULTS: A 1,800 bp DNA fragment containing the human HBx promoter and genomic DNA was microinjected into the male pronucleus of the fertilized eggs of mice. Three hundred and thirty-eight eggs survived from microinjection were transplanted into the oviduct of 16 pseudopregnant female, 12 pseudopregnant mice got pregnant and gave birth to 74 pups. Genomic DNA were extracted from the tails of the pups, Southern blot hybridization was used for determination of the integration of human HBx gene. The 1,800 bp microinjected fragment was used as the probe, 17 mice (founders) were identified of the integration of human HBx gene. Total RNA were extracted from the livers of the founders, all 17 founders were identified of the expression of human HBx gene by using Northern blot hybridization. CONCLUSIONS: These results may provide animal models for studying on the correlation between chronic HBV infection and the development of hepatocellular carcinoma.

Animals↗

PubMed2000

[The summarization of clinical experience of difficult tracheal intubation].

OBJECTIVE: To summarize our experiences and lessons of difficult tracheal intubation for clinical anesthesia reference. METHODS: We had done a retrospective analysis of clinical data on difficult tracheal intubation in 2,825 patients undergoing elective plastic surgery with anesthesia. The main causes of difficult tracheal intubation were the limitations of neck extension (n = 1,169), mouth opening (n = 889), both neck extension and mouth opening (n = 698), and micromaxillary deformity (n = 69). By the Cormack's classification, all the patients had the laryngeal exposure of grade II or more. The tracheal intubations were done under neuroleptanalgesia combined with topical spray of local anesthetic in 439 patients, intravenous anesthesia of sedative drugs and nondepolarizing relaxants of subnormal doses in 629 subjects, and total intravenous or inhaled anesthesia in 1,757 cases, respectively. RESULTS: The difficult tracheal intubations were completed using blind nasal intubations in 142 patients, blind oral intubations with direct laryngoscope in 2,377 patients, oral intubations with fiberoptic stylet rigid laryngoscope in 186 patients, and oral or nasal intubations with flexible fiberoptic bronchoscope in 72 patients. The incidence of successful intubation was 99.7%. The common complication of intubation was airway trauma and its incidence was 19.3% in all the patients. Anesthetic techniques could affect significantly the intubation time and the incidences of complications in the patients with difficult intubation. CONCLUSIONS: By the improvement of anesthetic methods and common intubation techniques, the intubation time and the incidence of complications in the patients with difficult intubations were reduced.

Adolescent↗

PubMed2000

Isolation and identification of cDNA fragments and full-length cDNA differentially expressed in human glioblastoma cell line BT-325 versus all-trans retinoic acid induction .

OBJECTIVE: To investigate the differentiation process of the human glioblastoma cells. METHODS: Differential display reverse transcribed-PCR (DDRT-PCR) was used to isolate the genes differentially expressed in control and all-trans retinoic acid treated human glioblastoma cell line BT-325. Routine method of cDNA library screening was performed to clone full-length cDNA. RESULTS: Thirty-six RT-PCR reactions were performed and 64 differentially expressed fragments were recovered, amplified and cloned. Of them, 46 ESTs were sequenced and delivered into the GenBank. The homology comparison using BLAST algorithm revealed that 22ESTs are highly homologous with the known genes and many of them play important roles in the cell differentiation progress. A dot-blot hybridization was conducted to certify the differentiation expression. The result showed that 27 EST clones are expressed at different level in control and all-trans retinoic acid treated BT-325 cells. A full-length cDNA was cloned using the EST-HGBB098. CONCLUSION: DDRT-PCR was a simple and effective method to serially analyze the differentially expressed genes.

Amino Acid Sequence↗

PubMed2000

[Relation between theoretical atomization efficiency and atomization temperature in GFAAS].

In this work, the relationship between the theoretical atomization efficiencies (EA') and atomization temperature (T) in graphite furnace atomic absorption spectrometry (GFAAS) for 18 elements were studied in detail. The results showed that a linear relationship between the EA' and the atomization temperature existed at a definite atomization temperature range. The correlation coefficient was within 0.9940-0.9993 for 18 elements. The slope was in the range of 0.06-0.07. The theoretical atomization efficiency was about 65% for all elements at optimized atomization temperature. This indicated that some factors should be taken into account in the L'vov modified model of characteristic mass.

English Abstract↗

PubMed2000

[Changes of trace elements in cells of lung cancer and cervix cancer before apoptosis and after apoptosis].

The sensitivity of total reflection X-ray fluorescence analysis (TXRF) is higher than normal X-ray fluorescence analysis (XRF). The cells of lung cancer and cervix cancer were researched before apoptosis and after apoptosis employed the method of TXRF on new transformed synchrotron radiation XRF experimental station of new 3W1A beam line which built on Beijing Synchrotron Radiation Facility (BSRF) of BEPC (new detector and spectrometer systems). We acquired their fluorescence spectrum of various elements before apoptosis and after apoptosis. We discovered there were interesting results that changes even remarkable changes of some elemental contents had occurred in these cells before apoptosis and after apoptosis. These alterations of elemental contents have served an inspiration for us: if their regularities of change are found, we will hope that some contributions would be done at the treatments of cancer.

Apoptosis↗

PubMed2000

[Discussions on some problems related to fluid inclusion analysis by SXRF].

X-ray fluorescence experiments were carried out at Beijing Synchrotron Radiation Facilities (BSRF) using synchrotron radiation as excitation source. The samples were made by mixing national reference standard GBW07106 and certain amount of reagent NaCl and KCl, and pressed into pellets. The purpose of the experiment is to verify the detection ability of the XRF setup at BSRF for elements in geological samples, especially for light elements. The beam size was 20 x 20 microns2, and the current in the storage ring was about 40 mA. The gap between the sample and the Si(Li) detector was 2 cm. With measuring time of 200 sec., The relative and absolute detection limits for 10 elements have been calculated. The sampling depth and sampling weight, which are critical in individual fluid inclusion analysis, have also been estimated. Some problems concerning the individual fluid inclusion analysis by SXRF, such as inclusion depth determination, effect of the inclusion depth on XRF intensity etc., are discussed based on the experiment results.

English Abstract↗

PubMed1999

Effect of substituents in directing the formation of benzochlorins and isobacteriochlorins in porphyrin and chlorin systems.

[formula: see text] A first synthesis of free-base fluorinated benzochlorins by acid-catalyzed cyclization of 20-(2-trisiloxy-trifluoromethylvinyl)octaethylporphyrin++ + is achieved. Under similar reaction conditions, the purpurin-18-N-hexylimide analogues produced the corresponding fluorinated and nonfluorinated ethylidene-substituted isobacteriochlorins and fluorinated chlorin, respectively. The structure of the porphyrin based fluorinated benzochlorin was also confirmed by X-ray analysis.

Crystallography, X-Ray↗

PubMed1999

Tissue inhibitor of metalloproteinase-1 inhibits apoptosis of human breast epithelial cells.

The signaling pathways critical for cell survival are mediated in part by the composition and integrity of the extracellular matrix and the action of its components on specific cell adhesion receptors. Withdrawal of anchorage-dependent epithelial cells from their association with ECM results in apoptotic cell death. Consistently, the matrix metalloproteinases (MMPs) or their inhibitors (TIMPs) have been suggested to regulate apoptosis. In this report, we investigated whether bcl-2 inhibition of apoptosis involves regulation of TIMP expression. We have found that bcl-2 overexpression induces TIMP-1 expression in breast epithelial cell lines (MCF10A, MCF10AneoT.TG3B, and MCF-7), whereas it has no effect on TIMP-2 expression. We demonstrated that TIMP-1 inhibits cell death induced by hydrogen peroxide, Adriamycin, or X-ray irradiation. In addition, TIMP-1 overexpression inhibits apoptosis after the loss of cell adhesion (anoikis) in MCF10A cells, suggesting that the antiapoptotic activity of TIMP-1 does not depend on its ability to stabilize cell-matrix interactions. We also showed that TIMP-1 overexpression is associated with constitutive activation of focal adhesion kinase, a signaling molecule known to be critical for the cell survival pathway.

Apoptosis↗

PubMed1999

Homicide mortality in the United States, 1935-1994: age, period, and cohort effects.

The authors analyzed homicide mortality data for the United States from 1935 to 1994, to delineate temporal trends and birth cohort patterns. This study included 850,822 homicide-attributed deaths documented by the National Center for Health Statistics, and incorporated graphical presentation, median polish, and Poisson regression modeling in an age-period-cohort analysis. Death rates from homicide in the United States doubled in the past four decades, with most of the increase having occurred during the 1960s and early 1970s. Poisson regression models confirmed that the rise of homicide mortality in both men and women was largely attributable to a significant period effect between 1960 and 1974. No discernible cohort patterns were found among women. However, homicide rates for recent male birth cohorts appeared to peak at younger ages and at higher levels. A significant increase in homicide mortality risk beginning with males born around 1965 was found by examining the residuals of median polish, and the second-order changes in the regression coefficients from the age-period-cohort model. The hike of homicide mortality during 1985 and 1994 was explained by this cohort effect. Increased prevalence of substance abuse and availability of firearms are two likely factors underlying this disturbing cohort pattern.

Adolescent↗