Biomedical subjects

F Li

Publications and source records attributed to F Li.

At least 289 records · Page 16Linked to original sources

PubMed1999

[Loss of heterozygosity and microsatellite instability in laryngeal carcinoma near p16 gene].

OBJECTIVE: To search for the minimal overlap region of tumor suppressor gene in laryngeal carcinoma and discuss the correlation of p16 gene with laryngeal carcinogenesis. METHODS: Five microsatellite polymorphism markers near p16 gene were selected to detect loss of heterozygosity (LOH) and microsatellite instability (MI) in 60 cases of laryngeal squamous cell carcinoma. RESULTS: The frequencies of LOH in 5 markers were less than 23.1%, while the frequencies of MI in 2 markers were higher, with the highest frequency (46.1%) in D9S1752. CONCLUSION: The results suggest that the deletion of p16 gene does not play an important role in the laryngeal carcinogenesis and there may exist a gene around D9S1752 participating in the development of laryngeal carcinoma, which correlates with the mutation of repair gene.

Gene Deletion↗

PubMed1999

[Rapid detection of trisomy 21 by quantitative polymerase chain reaction].

OBJECTIVE: Studying gene diagnosis of trisomy 21 by means of quantitative polymerase chain reaction(PCR). METHODS: Polymorphic short tandem repeat(STR) at D21S11 served as the gene marker, and a pair of primers was synthesized. The samples from 11 normal subjects and 28 cases of trisomy 21 were analyzed by quantitative PCR. RESULTS: 10 normal subjects showed two bands with a ratio of 1:1, and a subject showed one band. Of 28 cases of trisomy 21, 24 cases showed two bands with a ratio of 2:1, 3 cases showed three bands with a ratio of 1:1:1, and 1 case showed one band. CONCLUSION: Polymorphic STR at D21S11 is a valuable gene marker for diagnosis of trisomy 21. Trisomy 21 can be diagnosed rapidly and accurately within 24 hours by quantitative PCR.

Down Syndrome↗

PubMed1999

Expression of the apoptosis inhibitor, survivin, in nonmelanoma skin cancer and gene targeting in a keratinocyte cell line.

The recently described apoptosis inhibitor survivin is expressed in many human cancers, thus potentially contributing to disease progression and resistance to therapy. Its potential role in nonmelanoma skin cancer is unknown. By immunohistochemistry, survivin was expressed in 81% (17 of 21) of basal cell carcinomas (BCC) of both nodular and morpheaform subtypes, and in 92% (24 of 26) of cutaneous squamous cell carcinomas (SCC). Survivin was also expressed in 19 premalignant lesions of Bowen's disease (SCC in situ) and hypertrophic actinic keratosis (HAK), suggesting that its appearance occurs early during keratinocyte transformation. Survivin expression was detected by Western blotting in a model keratinocyte cell line, HaCat. Transfection of HaCat cells with green fluorescent protein (GFP)-conjugated survivin antisense or GFP-conjugated survivin dominant negative mutant (Cys84Ala) resulted in spontaneous apoptosis in the absence of other genotoxic stimuli. In GFP-conjugated survivin antisense transfectants, a decreased level of endogenous survivin was confirmed by flow cytometry. This was associated with a five-fold increase in the sub-G0/G1 fraction corresponding to apoptotic cells and a decrease in proliferating cells with 4N DNA content. These data demonstrate that apoptosis inhibition by survivin may participate in the onset and progression of both BCC and SCC, and suggest that therapeutic targeting of survivin may be beneficial in patients with recurrent or advanced disease.

Apoptosis↗

PubMed1999

[Construction and expression of HLA-DRalpha, DRB1*0401 transgenic mice model].

OBJECTIVE: To construct transgenic mice model on DR alpha and DRB1*0401 of human MHC-II molecules. METHODS: By microinjection techniques on germ nucleus of zygotes, DRalpha and DRB1*0401 genes were injected into zygotes of C57BL/6 x DBA/1 hybrid mice and transplanted into the oviducts of pseudopregnancy female mice. The integration and expression of exogenous genes in offspring were detected by PCR, Southern blot and Northern blot, RT-PCR analysis. RESULTS: There were 5 founders of all injected mice, which had steadily inherited to the fifth generation. It was found that 95 mice were positive by PCR and 68 mice were integrated exogenous gene by Southern blot analysis. DRalpha and DRB1*0401 genes were expressed on spleen and kidney of transgenic mice. CONCLUSION: This experiment on the construction of DRalpha and DRB1*0401 transgenic mice model is a success.

Animals↗

PubMed1999

Antiviral effects of rhIFN-alpha 1 against seven influenza viruses.

AIM: To study the antiviral effects of rhIFN-alpha 1 (Chinese silkworm gene recombinant interferon alpha 1) on 7 influenza viruses in MDCK cells and in mouse pneumonia caused by PR8 virus. METHODS: 100TCID50 virus (H1N1, H2N2, H3N3, type B, type C, clinical A1, and clinical B) were inoculated into MDCK cells, PR8 viruses were dropped nasally in mice, the antiviral effects of rhIFN-alpha 1 were observed. RESULTS: The minimal effective concentrations of rhIFN-alpha 1 against these 7 influenza viruses were 12.5, 25, 50, 25, 12.5, 25, and 12.5 kU.L-1, respectively. The infectious therapeutic indices of rhIFN-alpha 1 to these viruses in MDCK cells were 8 x 10(3), 4 x 10(3), 2 x 10(3), 4 x 10(3), 8 x 10(3), 4 x 10(3), and 8 x 10(3), respectively. The inhibitory indices of rhIFN-alpha 1 to the 7 influenza viruses in MDCK cells were 3.6, 4.7, 3.5, 3.3, 3.9, 4.6, and 3.5, respectively. The rhIFN-alpha 1 inhibited the intracellular replication of influenza viruses effectively, but did not kill viruses directly. The rhIFN-alpha 1 prolonged the life span of mice infected with pneumonia by influenza virus A strain PR8 to 94.2%-132.7%. It inhibited the inflammation and hyperplasia of interstitial fibers, and decreased the virus titer. The inhibitory rates of rhIFN-alpha 1 to pulmonary-indice were 14.8%-37.4%. CONCLUSION: rhIFN-alpha 1 inhibited the proliferation of influenza virus and improved the symptom of mouse pneumonia caused by influenza virus.

Animals↗

PubMed1999

[The investigation of natural antibody level to Haemophilus influenzae type b polysaccharide in China].

OBJECTIVE: Investigation of natural antibody level to Haemophilus influenzae type b polysaccharide in China. METHODS: 1,596 sera samples from cord (55 sera), infants (1,383 sera), children (66 sera), adult (52 sera) and elderly (40 sera) were collected from different provinces and the natural antibody level to PRP was measured with a standardized radio immunoassay 125I-labeled PRP. RESULTS: Antibody level of infants under 5 year olds in different provinces was different. Levels of infants from Gansu, Guizhou, Jiangxi province were lower (< or = 0.07 microgram/ml) than from Shanhai, Guangxi and Heilognjiang. Comparison of antibody levels with different age groups showed that infants aged 6 months to 5 years having the lowest antibody level (< 0.15 microgram/ml). The level increased rapidly during 6-10 years of age (> or = 1.0 microgram/ml). The levels of adults and elderly were about 1-1.5 micrograms/ml. CONCLUSION: General immunity against Hib disease were low in Chinese population. Children aged 6 months to 5 years old with lowest natural antibody level to PRP were the population under high risk.

Adolescent↗

PubMed1999

Immunological studies on the cellular phenotype involved in corneal allograft rejection.

OBJECTIVE: To investigate the cellular phenotype involved in corneal allograft rejection using wholemounts analysis. METHODS: Corneal transplantation was performed between Sprague Dawley (SD) and Wistar rats. Corneal wholemounts were prepared from control rats and those after corneal transplantation on day 7 and 12. Immunohistochemical stain was performed on these wholemounts using monoclonal antibodies to transforming growth factor beta 1(TGF-beta 1), CD3, CD4, CD8, B lymphocytes, macrophages, dendritic cells and major histocompatibility complex (MHC) class II antigen. RESULTS: Corneal allograft rejection started on day 7 and reached its maximum from 10 to 14 days after corneal transplantation. Presence of TGF-beta 1-, CD3-, CD4-, CD8-, MHC class II-positive cells, macrophages and dendritic cells were noted at the limbus of both SD rats and Wistar rats. No positive cell was present in the central cornea of normal rats. All positive cells but B lymphocyte were noted in large numbers in the cornea after corneal allograft transplantation. Marked staining for TGF-beta 1 was noted during graft rejection. CONCLUSION: The corneal wholemounts technique provides a good visualization for the cellular phenotype involved in corneal allograft rejection. A variety of cells including TGF-beta 1, CD3, CD4, CD8, MHC class II antigen positive cells, macrophages and dendritic cells are involved in corneal allograft rejection. TGF-beta 1-positive cell might be an important immunosuppressive factor after corneal transplantation and also involved in the induction of fibrosis.

Animals↗

PubMed1999

[Role of neuronal nitric oxide synthase in dynorphin spinal neurotoxicity and analgesia in rats].

OBJECTIVE: To investigate the different role of neuronal constitutive nitric oxide synthase (nc-NOS) in dynorphin (Dyn) A(1-17) spinal neurotoxicity and analgesia. METHODS: The cNOS activity in ventral and dorsal spinal cord in rats was measured with H-L-arginine conversion, and ncNOS immunoreactivity(IR) was observed with strepavidin-peroxidase immunohisto-chemistry. RESULTS: Intrathecal administration of Dyn A(1-17) produced dose-dependent paralysis of hindlimbs and tail as well as inhibition of tail flick (TF) and foot flinch (FF) reflexes. Dyn A(1-17) 10 nmol induced only transient paralysis and apparently reduced the ncNOS-IR in the superficial dorsal horn but did not induce any change of ncNOS-IR in the ventral horn cells as compared with saline control. Dyn A(1-17) 20 nmol produced permanent paraplegia with irreversible spinal cord damage, characterized by central and progressive necrosis. Dyn A(1-17) 20 nmol remarkedly induced the expression of ncNOS-IR in the ventral horn cells whereas inhibited ncNOS-IR in the superficial dorsal horn. Dyn A(1-17) 20 nmol also significantly increased the activities of cNOS in the ventral spinal cord but did not affect cNOS activities in the dorsal spinal cord. Intrathecal pretreatment with 7-nitroindazole (7-NI) 1 mumol, a selective ncNOS inhibitor 10 min prior to i.t. Dyn A(1-17) 20 nmol significantly ameliorated Dyn-induced neurological outcome, but TF and FF remained inhibited. 7-nitroindazole also significantly antagonized the increases of cNOS activities and ncNOS-IR in the ventral spinal cord at 4 h after i.t. Dyn A(1-17) 20 nmol, but did not affect or even potentiated Dyn-induced inhibition of cNOS activity and ncNOS-IR in the dorsal spinal cord. CONCLUSIONS: Over-expression or over-activation of ncNOS in the ventral spinal cord may be involved in Dyn spinal neurotoxicity, whereas as the reduction of ncNOS activities in the dorsal spinal cord might reflect Dyn spinal analgeisia or pain modulation.

Analgesics↗

PubMed1999

[Identification of beta-FBG-455G/A polymorphisms in 210 samples of Guangdong population and the relationship with plasma fibrinogen level].

OBJECTIVE: To analyze the frequency of beta-fibrinogen (beta-FBG) gene G/A-455 polymorphisms in Guangdong Chinese population and the relationship between genotype and plasma fibrinogen levels. METHODS: DNA of 210 samples were analyzed by using PCR-RFLP. Turbidimetric method for the levels of plasma fibrinogen was performed in 92 samples. RESULTS: The frequency of beta-FBG G/A-455 genotype A/A was 0.038; G/G was 0.514 and G/A was 0.448. The frequency of the A-allele was 0.262. The average plasma fibrinogen level in 46 samples of genotype G/A was (2.18 +/- 0.24) g/L and in 42 samples of G/G genotype was (2.03 +/- 0.25) g/L. There was significant difference between genotype and plasma fibrinogen (P < 0.01). CONCLUSION: The frequency of beta-FBG G/A-455 A-allele in Guangdong Chinese population is higher than that in European. The plasma fibrinogen level in G/A genotype is higher than that in G/G genotype. It suggested that the beta-FBG gene expression might be associated with the genotype.

Adolescent↗

PubMed1999

Serum leptin levels and adiposity in adult Chinese: a preliminary observation.

OBJECTIVE: To establish normal serum leptin levels in Chinese and investigate the relationship between serum leptin levels and body fat, gender, age and androgen. METHODS: Serum leptin levels were measured in 77 lean (BMI < 25) and 28 overweight or obese (BMI > or = 25) subjects by a radioimmunoassay (RIA) method. RESULTS: The serum leptin levels in lean Chinese were 2.15 +/- 1.46 ng/ml in male and 7.85 +/- 3.60 ng/ml in female, which are similar to those of Caucasians, while in overweight or obese ones, the levels were 4.87 +/- 3.47 ng/ml and 16.59 +/- 6.92 ng/ml respectively, lower than those in Caucasians. A 2-3 times higher leptin concentrations were found in women than in men in both conditions. Even when the number of lean males was expanded to 79 subjects aged from 17-80 years, no significant leptin-age relationship was found. Despite 25% of obese subjects manifested a relative deficiency of leptin, as a whole, leptin levels in both men and women were significantly correlated with BMI (r = 0.69, P < 0.001 in male and r = 0.63, P < 0.001 in female). CONCLUSIONS: Serum leptin levels in Chinese lean people are similar to those in Caucasians and in both lean and obese groups, the leptin levels are correlated with BMI, suggesting that the great majority of the obese patients are resistant to endogenous leptin. Those who are relatively deficient of leptin may become a group of good candidates for leptin treatment in the future.

Adult↗

PubMed1999

Molecular cytogenetic detection of trisomy 21 in interphase nuclei and metaphase chromosomes.

OBJECTIVE: To explore the potential application of molecular methodology in the detection of numerical chromosome aberration for clinical diagnosis and prenatal diagnosis of Down's syndrome. METHODS: The primed in situ labelling (PRINS) procedure was carried out by in situ annealing of specific oligonucleotide primers to chromosome 13, 16, 18, 21, X and Y, respectively, followed by primer elongation by a Taq polymerase in the presence of labelled nucleotides. Detection of the labelling sites was performed by immunocytochemistry and conventional fluorescence microscopy. RESULTS: Under the stringent annealing temperature, chromosomes 13, 16, 18, X and Y were specifically labelled at centromeres and the procedure was carried out successfully on interphase nuclei as well as on metaphase spreads with easily scorable signals. In 33 cases of uncultured peripheral blood lymphocytes and 11 cases of uncultured amniocytes tested, two fluorescence signals were shown on more than 87.6% interphase nuclei when chromosomes 13, 16, 18 were investigated. Sex chromosomes were correctly detected in the same way. Blind tests on peripheral blood lymphocytes from 14 cases of normal individuals and 12 cases of Down's syndrome patients and on 9 cases of amniocytes showed that when chromosome 21 was detected by PRINS, two fluorescence spots as positive signals were visible on 89.3% normal nuclei and three spots on 88.8% trisomic nuclei. The above results were fully compatible with karyotypic analysis. CONCLUSION: PRINS provides a rapid and efficient method for the clinical diagnosis or prenatal diagnosis of trisomy 21.

Amnion↗

PubMed1999

Quantitative analysis of TGF-alpha and EGFR mRNA in laryngeal carcinoma tissues.

OBJECTIVE: To elucidate the stimulating role of the growth factor autocrine loop in the carcinogenesis and development of laryngeal carcinomas. METHODS: The reverse transcription-polymerase chain reaction technique was applied, and with beta-actin as internal standard, TGF-alpha and EGFR mRNA in laryngeal carcinomas, macroscopically normal laryngeal mucosas adjacent to the tumor and in vocal cord polyps were quantitatively examined. RESULTS: The mRNA index of both TGF-alpha and EGFR in laryngeal carcinomas and adjacent mucosas was significantly higher than those in vocal cord polyps (P < 0.05). The index of TGF-alpha mRNA was significantly higher in laryngeal carcinomas than in mucosas adjacent to the tumor (P < 0.05). CONCLUSIONS: The autocrine system consisting of TGF-alpha and EGFR may play an important role in the very early stage of laryngeal carcinoma, or even when the tissue phenotypic alteration does not occur. The elevated TGF-alpha mRNA level may trigger a switch from genotypic alteration to the phenotypic. The results are expected to be a theoretical basis for the preventive chemotherapy of laryngeal carcinomas.

Carcinoma, Squamous Cell↗

PubMed1999

[A methodological study on the evaluation of insulin resistance in vivo].

OBJECTIVE: To investigate the advantage and disadvantage of several methods often used to evaluate insulin resistance and to attempt to modify the disadvantage. METHODS: Three protocols of minimal model technique (MMT), three protocols of basal state approach and four protocols of oral glucose tolerance test (OGTT) were used respectively to calculate insulin sensitivity index (ISI) in 16 subjects with normal glucose tolerance (NGT) and 13 patients with non-insulin-dependent diabetes mellitus (NIDDM). ISI of classical MMT was regarded as standard; ISI of other protocols were analyzed, assessed and compared with that of classical MMT. RESULTS: Except the ISI expressed by the ratio of fasting serum glucose to insulin concentration (FSG/FIns) and the ratio between area under curve (AUC) of glucose and insulin (AUCg/AUCi) in OGTT, ISI of other protocols was significantly higher in NGT group than in NIDDM group (P < 0.05, ISI relative values were 1 and 0.44 - 0.70 respectively) and had stronger relationships as compared with ISI of classical MMT (r = 0.45 - 0.92, P < 0.05). CONCLUSION: The modifications that reduce the samples to 12 or 10 and shorten the time to 120 min for MMT are feasible. Both the homeostasis model assessment and the basal state method designed by LI Guangwei are very simple; they can roughly evaluate insulin sensitivity. OGTT designed by Cederholm is a relatively simple and precise method of measuring IR. Two protocols of OGTT designed by the authors may be accurate methods for evaluating IR. Both FSG/FIns and AUCg/AUCi can not reliably evaluate insulin sensitivity.

Adult↗

PubMed1999

[A clinical research for eosinophilic meningoencephalitis caused by angiostrongyliasis].

OBJECTIVE: To improve the awareness of angiostrongyliasis. METHODS: The clinical and laboratory data as well as the epidemiological informations of 18 patients with eosinophilic meningoencephalitis caused by Angiostrongylus cantonensis were analyzed. RESULTS: All the patients had a history of eating raw fresh water snail (Ampularium canaliculatus) before the onset of the disease. Incubation period ranged from 1 to 25 days. The major symptoms of the patients were severe headache and pain in the trunk and limbs. Peripheral blood eosinophilia was noted together with increased eosinophilic count in cerebrospinal fluid. With ELISA sera from patients were specifically IgG-antibody positive against Angiostrongylus cantonensis antigen, but were negative against other parasitic antigens such as Paragonimus westermani, Cysticercus, Cellulosae hominis, Echinococcus granulosus and Trichinella spiralis. Abnormal spot signal was found in 2 cases with brain magnetic resonance imaging. Electroencephalogram showed slow alpha rhythm. All the patients were effectively treated with good combined administration of albendazole and dexamethasone. CONCLUSION: Angiostrongyliasis is one of the common causes leading to eosinophilic meningoencephalitis. To our knowledge, Wenzhou is the first small outbreak site discovered of angiostrongyliasis in mainland China.

Adult↗

PubMed1999

[Dynamic effect of the blood glucose and insulin on serum leptin concentration during oral glucose tolerance test].

OBJECTIVE: To investigate the effects of internal change of plasma glucose and serum insulin levels on serum leptin concentrations during oral glucose tolerance test (OGTT) in normal subjects and type II diabetics (DM). METHODS: Plasma glucose, serum insulin and leptin concentrations were measured simultaneously in 50 age, sex and body mass index matched non-diabetic (non-DM) and 50 DM subjects who were undergoing OGTT. RESULTS: The fast serum leptin concentrations were (3.88 +/- 0.64) microg/L in DM males and (8.30 +/- 1.06) microg/L in DM females. Respectively they were (5.01 +/- 0.64) microg/L and (10.48 +/- 1.30) microg/L in non-DM group. No significant difference was revealed. Comparing with the non-DM group, the glucose curve was elevated and the insulin releasing curve was characterized by a low response and a delayed peak in DM group. As for the leptin releasing curve, both groups showed a decreasing trend, which seemed to be more evident in DM group. CONCLUSION: Leptin concentration does not increase with the release of insulin. On the contrary, it shows a diurnal rhythmic descending trend, suggesting that in vivo, the insulin effect on serum leptin concentration is relatively weak and not able to affect the day-time descending trend of leptin levels.

Blood Glucose↗

PubMed1999

[Effects of EB virus LMP on the differentiation and growth of human nasopharyngeal carcinoma cell line CNE1].

OBJECTIVE: To study the effects of EBV-LMP gene on differentiation and growth of human nasopharyngeal carcinoma (NPC) cell. METHODS: With NPC cell line (CNE1) as target, electroporation was used to transfect EBV-LMP gene and the vector into CNE1 cells. The proliferation changes of transfectants were measured in vitro by proliferation experiment. FCM method and transplantation in nude mice were used. RESULTS: LMP promoted the growth ability of NPC CNE1 cells in vitro. The average A ratio (3.98 +/- 0.11) in the treatment group was higher than in the control group (2.36 +/- 0.05) and also in the negative control group (2.75 +/- 0.07, P < 0.01). Clone forming test (25.2%, 378/1 500) in the treatment group was higher than in the control groups (11.2%, 168/1 500) and negative control groups (13.4%, 201/1 500). When FCM method was used, the keratin positive rate (82.7%) in the treatment group was markedly decreased as compared with the control (92.5%) and negative control groups (95.7%, P < 0. 05). Latent period (26.6 +/- 7.7) days and internal double time (2.51 +/- 0.18) days of transplant tumor of the treatment group were markedly shortened, tumor take rate (5/6) was increased, cells of the transplant tumor in the treatment group showed an image of small size, great allotype, and a trend of low differentiation. CONCLUSION: The EBV-LMP can promote the growth and inhibit the differentiation of NPC CNE1 cells. EBV-LMP may play an important role in the development of NPC and in studying its mechanism.

Animals↗

PubMed1999

[Epstein-Barr virus infection and expression of T-cell intracellular antigen-1 (TIA-1) in intestinal T-cell lymphoma].

OBJECTIVE: To study the status of Epstein-Barr virus (EBV) infection and the expression of TIA-1 antigen in 24 cases of intestinal T-cell lymphomas. METHODS: In situ hybridization for EBER1/2; immunohistochemical staining by three step ABC technique for TIA-1, LMP-1, CD30, CD45RO, CD3 AND CD20. 19 cases of intestinal B-cell lymphomas were used for comparison. RESULTS: (1) Of the 24 intestinal T-cell lymphoma cases, 23 were pleomorphic, medium to large cell type, and one cases was small cell type; in 20 of the 24 cases EBER1/2 signals were detected in the tumor cells; in 4 of the 20 EBER1/2 positive cases, tumor cells expressed LMP-1; EBER1/2 was not detected in 19 cases of intestinal B-cell lymphomas. (2) in 23 of the 24 cases, TIA-1 was expressed in most tumor cells, but not in the only case of small cell type; TIA-1 was negative in tumor cells of all 19 cases of intestinal B-cell lymphomas. CONCLUSIONS: A high level of EBV infection was present in this group of intestinal T-cell lymphomas, the expression of TIA-1 may be related to its cell origin. Intestinal T-cell lymphoma may be an EBV-associated extranodal NK/T cell lymphoma.

Adolescent↗

PubMed1999

[Separation and identification of thellungianin G from the root of Pimpinella thellungiana Wolff].

OBJECTIVE: To study the effective components in the root of Pimpinella thellungiana METHOD: Column chromatography with silica gel and ODS was employed for the isolation and purification of ingredients. Their structures were elucidated by spectral analysis. RESULT: Three compounds were obtained and identified as 2-(1',2'-epoxy)-4-methoxy pheryl-2-methyl-butyrate(I),4-(1'-propenyl) phenol(II) and 2-methyl butyric acid(III). CONCLUSION: Compound I is a new compound and named thellungianin G. Compounds II and III were separated from P. Thellungiana for the first time.

Phenylbutyrates↗