Biomedical subjects

G Li

Publications and source records attributed to G Li.

At least 235 records · Page 13Linked to original sources

PubMed2001

Detection of human herpesvirus 8 DNA in acute leukemia patients.

OBJECTIVE: To determine the prevalence of human herpesvirus 8 (HHV-8) DNA in acute leukemia (AL) patients. METHODS: The presence of HHV-8 DNA sequences in peripheral blood mononuclear cells (PBMC) and bone marrow mononuclear cells (BMMC) from 50 AL patients was examined using polymerase chain reaction (PCR). Nine human hematopoietic cell lines and PBMC from 30 normal donors were also included. RESULTS: HHV-8 DNA sequences were detected in one case of acute myelogenous leukemia (AML). The specimens from the bone marrow aspirate, peripheral blood and serum of this patient were all positive. None of the normal donors and human hematopoietic cell lines showed evidence of HHV-8 DNA. CONCLUSION: The results suggest that the prevalence of HHV-8 is low in AL in China.

Acute Disease↗

PubMed2001

Differentiation of NIH3T3 fibroblasts into adipocytes induced by peroxisome proliferator activated receptor gamma 2 expression.

OBJECTIVE: To express mouse peroxisome proliferator activated receptor gamma 2 (mPPAR gamma 2) in NIH3T3 fibroblasts mediated by the recombinant retrovirus and study its function. METHODS: The mPPAR gamma 2 gene was subcloned into retrovirus vector pGCEN to generate the recombinant pGCEN/mPPAR gamma 2. Then it was packaged into PA317 cells and selected with G418. Viral supernatants were harvested and then used to infect NIH3T3 fibroblasts. PPAR gamma activator 5, 8, 11, 14-eicosatetraynoic acid (ETYA) was used to induce the mPPAR gamma 2-expressing NIH3T3 cells into adipocyte differentiation. RESULTS: The recombinant retrovirus pGCEN/mPPAR gamma 2 was constructed, and the higher titers of the viral supernatants were obtained. mPPAR gamma 2 was expressed in NIH3T3 cells mediated by the recombinant retrovirus. Lipid accumulation obviously existed in these induced adipocytes which morphologically resembled mature adipocytes in vivo and expressed tissue specific adipocyte P2 (AP2) and Leptin genes. CONCLUSIONS: An adipocyte differentiation model in vitro was successfully established. The work is the basis for further research on the molecular mechanism of adipocyte differentiation induced by PPAR gamma 2.

3T3 Cells↗

PubMed2001

Monoclonal anti-idiotype antibody bearing the internal image of nasopharyngeal carcinoma associated antigen.

OBJECTIVE: To generate and characterize anti-idiotypic monoclonal antibody (Ab2) that bears the internal image of nasopharyngeal carcinoma (NPC) associated antigen. METHODS: Using NPC monoclonal antibody (Ab1) as immunogen, hybridoma cells were obtained by fusion of SP2/0 myeloma cells with immunized murine spleen cells. Positive clones were screened by Sandwich ELISA and a binding inhibition test. To determine whether Ab2 possess the internal image of the original antigen or not, mice were immunized with Ab2. ELISA and the competitive inhibition assay tested anti-anti-idiotypic antibodies (Ab3) in anti-sera. Cell-mediated immunity to tumors induced by Ab2 was investigated by a delayed-type hypersensitivity response and the mouse T-cell proliferation assay. RESULTS: Anti-idiotypic monoclonal antibodies against the monoclonal anti-NPC antibodies FC2 and HNL5 were generated that recognize NPC associated antigens. These Ab2, which were designated 2H4 and 5D3, could inhibit the binding of FC2 or HNL5 to NPC cell lines. Anti-sera from the immunized mice, which contained Ab3, could compete with FC2 or HNL5 for binding with NPC cell by a competitive inhibition assay. Mice immunized with 2H4 or 5D3 coupled with keyhole limpet hemocyanin (KLH), showed a positive and specific delayed-type hypersensitivity (DTH) reaction after stimulation by NPC cells. The mouse T cell proliferative assay indicated that there was a significantly higher proliferative response of the splenocytes in the experimental groups than that in control groups. CONCLUSIONS: Anti-idiotypic antibodies 2H4 and 5D3 are Ab2 beta bearing the internal image of the epitope of NPC associated antigen. Either 2H4 or 5D3 expressing three-dimensional shapes that resemble the structure of natural antigens could induce humoral and cellular immune response.

Animals↗

PubMed2001

Ultrastructure of intrahepatic biliary canaliculi and prognosis of congenital biliary atresia.

OBJECTIVE: To investigate the relationship between the ultrastructure of intrahepatic biliary canaliculi and the prognosis of congenital biliary atresia. METHODS: Liver biopsies from 25 patients who were operated on for congenital biliary atresia were examined under the transmission electron microscope. The relationship between the number of well-developed bile canaliculi and patient prognosis was studied. RESULTS: The survival rate for 13 patients with well-developed intrahepatic biliary canaliculi and 12 patients with poorly-developed intrahepatic biliary canaliculi were 92.3% (12/13) and 33.3% (4/12) respectively. The difference between two groups was statistically significant (P < 0.05). CONCLUSIONS: Intrahepatic biliary canaliculi ultrastructure could be used as one of the prognostic factors in congenital biliary atresia.

Bile Canaliculi↗

PubMed2001

Molecular cloning and characterization of NAG-7: a novel gene downregulated in human nasopharyngeal carcinoma.

OBJECTIVE: To identify novel tumor suppressor genes at chromosome 3p24-26 in human nasopharyngeal carcinoma (NPC). METHODS: Twenty epithelial-derived expressed sequence tags (EST) were selected from chromosome 3p24-26. RT-PCR and Northern blot were used to detect the expression of the ESTs in NPC cell line, HNE-1, and primary cultures of normal nasopharyngeal epithelial cells. One EST, which was substantially downregulated in the HNE-1 cell line, was detected in 19 NPC biopsy samples. cDNA library screening was used to get its full sequence and the sequence of this novel gene was analyzed. RESULTS: A novel gene located at chromosome 3p25.3 was obtained and named NAG-7. It was downregulated in 26.3% (5/19) of NPC biopsy samples. Its 1677 bp full length cDNA had a potential open reading frame predicting a 94 amino acid protein with a molecular weight of 11,023.87 Dalton. Analysis of the NAG-7 gene showed that it was a transmembrane protein containing a protein kinase C phosphorylation site and a myristyl site. It has no significant homology to any reported genes in the database of GenBank. CONCLUSION: NAG-7 is a novel gene downregulated in NPC, suggesting that it may be involved in the development of NPC.

Amino Acid Sequence↗

PubMed2001

Mechanism and kinetics of low-temperature thermochemical conversion process for sewage sludge.

The low-temperature thermo-chemical conversion process for sewage sludge is a prospective technology, through which the energy in the sludge can be recovered. With the help of elementary analysis of sewage sludge and its conversion products, thermal gravimetric analysis (TGA) of the sludge and GC/MS analysis of the derived oil, a study was carried out on element transfer, characteristic conversion temperature and conversion reaction mechanism of the process. The following results are obtained: 1) the predominant conversion reactions are distillation of aliphatic compounds, splitting of protein peptide bonds and group transfer; and 2) the main components involved in the conversion are aliphatic compounds and protein, with the lower reaction temperature for the former, the higher for the latter and the highest for saccharides. Based on the mechanism analyses, the simplified reaction model of the thermo-chemical conversion process for sewage sludge consists of two serial competitive reactions (producing volatile matter and char respectively). The estimated Arrhennius kinetic parameters of the reaction model based on TGA testing resultsare A1 = 4.15 x 10(6) 1/s, n1 = 2, E1 = 98 kJ/mol; A2 = 1.42 x 10(5) 1/s, n2 = 2, E2 = 85 kJ/mol; A3 = 1.01 x 10(12) 1/s, n3 = 4, E3 = 190 kJ/mol; A4 = 1.33 x 10(9) 1/s, n4 = 4, E4 = 146 kJ/mol.

Conservation of Natural Resources↗

PubMed2001

[Serum leptin level in hemodialysis patients and its relation to their nutritional status].

OBJECTIVE: To investigate the leptin levels of hemodialysis (HD) patients and the relation to their nutritional status. METHODS: Thirty maintenance hemodialysis patients and thirty healthy control subjects were recruited for the study. Blood was drawn after an overnight fast. Serum leptin was measured using a human leptin RIA kit. There were also blood tests to measure BUN, creatinine, serum albumin, transferrin, prealbumin, insulin, cholesterol etc. RESULTS: Mean serum leptin concentration was significantly higher in the HD group than that in the control (P < 0.01). HD group had significantly higher concentrations of BUN, creatinine, serum albumin, transferrin and prealbumin (P < 0.01). Leptin levels in HD patients correlated positively with body mass index (BMI), total systemic flow (TSF), and concentration of insulin (r = 0.53, 0.66, 0.57, respectively, P < 0.01). No significant correlations were observed in HD patients between leptin and BUN or creatinine, or between leptin and nutritional indices. CONCLUSION: Our data suggests that leptin is markedly increased in HD patients. Serum leptin correlates strongly with BMI, TSF and insulin level. No significant correlations were observed in HD patients between leptin and other indices.

Adult↗

PubMed2001

[Hypermethylation of the calcitonin gene as molecular genetic marker in detecting minimal residual disease of leukemia].

OBJECTIVE: To explore whether detecting minimal residual disease (MRD) of leukemia with hypermethylation of the calcitonin gene as molecular genetic marker of leukemic clone may predict the prognosis. METHODS: Polymerase chain reaction (PCR) in combination with digestion of DNA with HpaII was used to examine the methylation patterns of the calcitonin gene in 29 cases with acute leukemia and 8 cases with transformation of chronic myeloid leukemia. By using PCR, MRD was longitudinally detected in patients who were positive for hypermethylation of the calcitonin gene as molecular genetic marker. RESULTS: Twenty patients with acute leukemia and transformation of chronic myeloid leukemia had MRD after complete remission. Bone marrow relapse occurred soon when MRD persisted or reappeared. It may predict bone marrow relapse two to eleven months earlier. The patients who were negative for MRD early and remained persistently negative may acquire prolonged survival. CONCLUSION: MRD of leukemia may be monitored by using PCR with hypermethylation of the calcitonin gene as molecular genetic marker for leukemic clone. It may prove useful in predicting the prognosis of leukemia.

Adult↗

PubMed2001

[Adipocytes differentiation of NIH3T3 cells induced by peroxisome proliferator activation receptor gamma 2 expression].

OBJECTIVE: To express the mouse peroxisome proliferator activated receptor gamma 2(mPPAR gamma 2) in NIH3T3 cells mediated by the recombinant retrovirus and study its function. METHODS: mPPAR gamma 2 gene digested from the recombinant plasmid pcDNA3/mPPAR gamma 2 and confirmed to contain the target gene segment with fluorescence-sequencing was subcloned into retrovirus vector pGCEN to generate the recombinant retrovirus pGCEN/mPPAR gamma 2. The recombinant retrovirus pGCEN/mPPAR gamma 2 and pGCEN were packaged with PA317 cells and anti-G418 clones of PA317 cells were selected. Viral supernatants were collected and used to infect NIH3T3 cells. Peroxisome proliferator activated receptor gamma 2 (PPAR gamma 2)-expressing NIH3T3 cells cultured in the differentiation media containing PPAR gamma activator ETYA were induced into adipocytes. RESULTS: The recombinant retrovirus pGCEN/mPPAR gamma 2 was constructed, 5 x 10(4) CFU/ml of the viral supernatants containing pGCEN/mPPAR gamma 2 and 6 x 10(5) CFU/ml of the viral supernatants containing pGCEN were obtained. mPPAR gamma 2 was expressed in NIH3T3 cells mediated by the recombinant retrovirus. Lipid accumulation obviously existed in PPAR gamma 2-expressing NIH3T3 cells at 10 days postdifferentiation and the lipid-containing cells morphologically resembled the mature adipocytes in vivo. CONCLUSION: An adipocyte differentiation model in vitro was established. The work is the basis for further researches on the molecular mechanism of adipocyte differentiation induced by PPAR gamma 2.

3T3 Cells↗

PubMed2001

[Cerebral watershed infarcts].

OBJECTIVE: To investigate the clinical types and characteristics of cerebral watershed infarcts (CWI). METHODS: Analysis of the clinical data and imaging characteristics of 192 cases with CWI confirmed by CT scan or MRI. RESULTS: In 69 cases (35.9%), CWI appeared as wedge-shaped areas on CT scan or MRI, the infarcts located at marginal zones between the anterior and middle cerebral arteries and were usually associated clinically with hemiparesis, transcortical motor aphasia and dementia. In 74 cases (38.5%) the infarcts also appeared as wedge-shaped areas on CT scan and MRI, but located at marginal zones between the middle and posterior cerebral arteries, the patients mainly showed mild hemiparesis and apathy. In 49 cases (25.5%), the long-line or triangle-shaped infarct areas usually located at marginal zones between the superficial and deep territory of the middle cerebral arteries in the basal ganglia and posterolateral angulus frontalis. CONCLUSION: The presentation of CWI is complicated, and the diagnosis of that mainly depends on imaging studies such as CT scan and MRI.

Adult↗

PubMed2001

[The surgical treatment for cerebellopontine angle meningioma].

OBJECTIVE: To discuss the risks and benefits of the surgical treatment for cerebellopontine angle meningioma. METHODS: Eighty-eight patients with cerebellopontine angle meningioma treated surgically in the last twenty years were analyzed retrospectively. All patients were followed up from six months to eleven years. RESULTS: Complete resection was done in 68 (77.3%) patients and subtotal resection in the rest 20 patients. Six(6.8%) patients died after the operation. Follow up showed that eight (13.3%) patients died and six (10%) patients developed recurrence. CONCLUSION: Surgery is the treatment of choice for cerebellopontine angle meningioma. It is the key to rationally choose the adequate approach, carefully manage and protect the vessels, nerves, brain stem and to institute timely and rationally the auxiliary therapy for the postoperative complications in order to increase the efficacy and improve the patients' quality of life.

Adolescent↗

PubMed2001

[Development of a system for robot aided teeth alignment of complete denture].

OBJECTIVE: To develop a robot aid aligning artificial teeth for complete denture. METHODS: The CRS-450, a 6-direction-free robot was utilized to make the grasped object realize any position and pose, and to develop an adjustable tooth arrangement machine. The geometry parameters of the shape of agomphious jaw were obtained through 3-D laser scanning and measuring system. The math's model, which was set up according to senior prosthodontic experts' experiences on tooth arrangement, was used to control program of experts in arranging teeth, 3-D denture simulation, and robots in arranging teeth. The program used VC++ and RAPL robot languages. When the teeth arrangement plan was formed, the data were transmitted to a robot, who would fix the position and finish the fabrication of complete denture. RESULTS: A complete system of robot-aided complete denture teeth arranging was set up and tried using this system to make an artificial dentition for a patient. There were still some errors in the articulation of the dentition, which needed adjustment and perfection. CONCLUSIONS: We succeed in using robot to fabricate artificial dentition for the first time. Although the dentition is not perfect in articulation, the system's scientific significance is profound. The results have proved that the designing idea and technical routine are workable.

Denture Design↗

PubMed2001

[A study on the epidemiology of Helicobacter pyroli infection among immigrants in Three Gorges area].

OBJECTIVE: To investigate the epidemiologic features of Helicobacter pyroli (Hp) sero-prevalence rates among immigrants in Three Gorges area. METHODS: Enzyme labelled immuno-sorbant-assay was used to determine the Hp prevalence rate. A case-control study including 1 600 immigrants as cases and 1 600 non-immigrants as controls was carried out to explore the features of Hp infection in Three Gorges area. RESULTS: The prevalence rate of Hp in immigrant area was 67.50% higher than 53.19% that of Hp in non-immigrant (chi(2) = 13.40, P < 0.01). Rate of Hp infection was highest in infants than in children, increasing with age to clearly show a positive correlation between age and Hp prevalence rate (r = 0.62, P < 0.01). However, there was no marked sex difference in Hp infection rates in the immigrant area. Same results were also presented in the non-immigrant area. Hp prevalence rates were different which related to the stages of flooding. It is 89.17% in the area of first stage, while in second and third stages of flooding, the rates were 76.40% and 62.20% respectively. CONCLUSION: Preliminary result indicated that Hp infection rate of immigrant area was higher than that of non-immigrant area. It appeared that living condition, environment, education condition might possibly have played important role in Hp prevalence. It is more important to prevent from infected children. Further study with respect to Hp prevalence rate was necessary when immigration is completed and the standard of living improved.

Adolescent↗

PubMed2001

[The relationship of clinicopathology and immunophenotypes in non-Hodgkin's lymphomas of the spleen].

OBJECTIVE: To investigate the relationship between clinicopathologic features and immunophenotypes in non-Hodgkin's lymphoma (NHL) of the spleen. METHODS: Clinicopathologic analysis and follow up; immunohistologic staining by SP method and EBER in situ hybridization. RESULTS: (1) Splenomegaly was found in all 19 cases of spleen NHL, 10 of the 19 (52.6%) cases had masses or a mass in their enlarged spleen; (2) 14 of the 19 (73.7%) cases were of B-cell type (including 5 cases of follicular type and 9 cases of diffuse type), in which 8 cases were centroblastic, 3 of centroblast/centrocyte and 4 cases of small lymphocyte types; all 10 cases of primary splenic lymphomas (PSL) were B-cell type; (3) 5 of the 19 cases (26.3%) had peripheral T-cell origin, including 4 cases of large cell type and 1 case of small cell type; of the 3 TIA-1 positive cases, 2 were also positive for EBER 1/2 (one CD 8+ and another CD56+), the remaining case was CD8-, CD56-, EBER1/2-; all 5 cases were secondary NHL of the spleen; (4) Follow up data were obtained for 14/19 cases (73.7%). 8 of 9 surviving cases were primary NHL. The range of survival period varied from 8 to 10 years. All 5 deceased cases had secondary NHL and their survival period was 2 to 6 months. CONCLUSIONS: Some relationship exists between the clinicopathology and origin of the tumor cells in splenic NHL, the prognosis of primary NHL is better than that of the secondary NHL and the diagnosis of primary NHL should be made with discretion.

Adolescent↗

PubMed2001

[Cytotoxic natural killer/T-cell lymphomas of the lymph nodes].

OBJECTIVE: To investigate the clinicopathologic features of cytotoxic natural killer (NK)/T-cell lymphomas of the lymph nodes. METHODS: Clinicopathologic observations and follow up on 5 cases of cytotoxic NK/T-cell lymphomas of the lymph nodes, immunohistochemical staining for CD45RO, CD8, CD56, CD30, CD20, TIA-1 and in situ hybridization for EBER1/2 were performed. RESULTS: (1) The clinicopathologic features of cytotoxic NK-T-cell lymphomas of the lymph nodes were summarized; (2) The tumor cells were positive for CD45RO in 4 of the 5 cases, in which 3 cases were also positive for CD56. One case was of null cell type. The tumor cells were positive for TIA-1 and EBER1/2 in all 5 cases. CONCLUSIONS: The clinicopathological features and special immunophenotypes of cytotoxic NK/T-cell lymphomas of the lymph nodes were present in all 5 cases. Clinically, this entity tends to be an aggressive process with poor prognosis.

Adult↗

PubMed2001

[A study on the effects of CD3AK cells on the improvement of cellular immune function in burned patients].

OBJECTIVE: To explore new ways of correcting postburn immune suppression in severely burned patients. METHODS: CD3AK cells were cultured in serum-free medium and were employed to treat patients with major burns. Similar patients treated by routine treatment were set to be control group. The changes of cellular immunological indices were dynamically observed in the patients of two groups at different time points. RESULTS: Compared to those in control group, the ratio of CD4+ cell of T cell subgroup increased in patients treated by CD3AK, in concomitant with the decrease of the ratio of CD8+ cells and the increase of the ratio of CD4/CD8. Serum soluble IL-2R level decreased. T lymphocyte transforming activity increased and NK cell activity increased. CONCLUSION: CD3AK cells cultured in serum-free medium could improve and restore the decreased cellular immune function in burn patients.

Adult↗

PubMed2001

[Effects of tetrandrine on the synthesis of collagen and scar-derived fibroblast DNA].

OBJECTIVE: To investigate the effects of tetrandrine on the synthesis of collagen and scar derived fibroblast DNA. METHODS: Scar-derived human fibroblasts were cultured in vitro. The changes in the levels of the synthesis of collagen and DNA of the fibroblasts were represented by the incorporation values of (3)H-TdR and (3)H-proline into the cells. Tetrandrine was added to the culture media of the cells, and its effects were studied. RESULTS: When the concentration of added tetrandrine increased from 5 mg/L to 80 mg/L, The (3)H-TdR values in scar-derived fibroblasts were 1162 plus minus 226 and 412 plus minus 82, respectively while that in control group was 1740 plus minus 165, showing an inhibition rate of 76.32%, and the difference (P < 0.01). In addition, the (3)H-proline incorporation values in the cells were 535 plus minus 141 and 341 plus minus 89, respectively, while that in control group was 1126 plus minus 193, with the inhibition rate of 69.71%, showing significant difference (P < 0.01). CONCLUSION: The synthesis of DNA and collagen in cultured scar-derived fibroblasts could be inhibited by tetrandrine in dose-dependent pattern. Tetrandrine might be a potential agent for the prevention and treatment of proliferative scars.

Alkaloids↗

PubMed2001

[Investigation on method speliality in identifying Fructus Crataegi with vitexin rhamnoside].

The methanol extract of Fructus Crataegi was purified on macro-reticular resins(model DM130)-polyamide column. Vitexin rhamnoside(I) was identified from Fructus Crataegi by TLC on polyamide layer sheets. The false and the confused species of Fructus Crataegi and some traditional Chinese herbal medicines which contain vitexin were studied by the same method. The results indicated that compound I was special constitute of Fructus Crataegi and the identification method of Fructus Crataegi with I was special.

Apigenin↗