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Biomedical subjects

L Zeng

Publications and source records attributed to L Zeng.

At least 109 records · Page 6Linked to original sources

[Clinical study of metastasis of thoracic lymph node in resectable lung cancer].

OBJECTIVE: To study the metastatic pattern of thoracic lymph node in resectable lung cancer. METHODS: From January 1992 to July 1998, the lymph nodes in hilar(N1) and mediastinal(N2) were resected based on their distribution in 160 patiens with resectable lung cancer and were examined by pathology. Number, size and colour of lymph nodes in each regions were recorded. Each lymph node was examined by routine pathology and immunohistochemistry. Quantity of metastatic lymph node was reported according to their regions. RESULTS: 99 cases(61.9%) had thoracic lymph nodes metastasis and 73 cases (45.6%) had mediastinal lymph nodes metastasis. Of those, only N1 metastasis was 16.3%, from N1 to N2 metastasis was 32.5%, only N2 metastasis was 13.1%. The metastatic frequencies in 11, 10, 7, 5 and 4 regions around the hilar or root of lung were 30.0%, 27.5%, 16.9%, 28.8% and 20.0%, respectively. Those were higher than 9, 6, 3, 2 and 1 regions far from the root of lung. The metastatic rate of lymph node in 2.0 cm or greater, 1.0 cm or greater and less than 1.0 cm was 60.7%, 15.5% and 4.3%, respectively (P < 0.001). The smallest metastatic lymph node was only 0.2 cm x 0.2 cm. Statistical analysis revealed that metastatic rate of thoracic lymph nodes was not relevant to different area, size and course of tumors. CONCLUSIONS: The lymph nodes metastases of most cases were spreading from the near to the distant, from lower to upper, through the hilar to the mediastinal. Lymph nodes metastases occurred easier in SCLC than in NSCLC (P < 0.05). It must be depended on pathologic examination to confirm whether or not the tumor has metastasis to lymph node.

Female↗

[Cloning and monoclonal antibody preparation of VEGF receptor KDR extracellular V-VII domain and KDR expression in carcinomas of different origins].

OBJECTIVE: To examine the expression of VEGF receptor KDR in carcinomas of different origins and provide possibility of exploring its relation to tumor growth and metastasis. METHODS: VEGF receptor KDR cDNA (V-VII) fragment was cloned from human umbilical vein with RT-PCR and expressed in E. coli Jm109. The purified GST-KDR fusion protein was used to immunize Balb/c mice and monoclonal antibody against KDR was prepared. With this monoclonal antibody, tumor tissue and related normal tissue of different origins were examined immunohistochemically for KDR expression. RESULTS: The frequency and intensity of KDR expression in different tumor tissues were obviously different. Transitional-cell cancer of urinary bladder was 100% KDR positive and with highest intensity, while KDR expression in breast and intestinal adenocarcinoma was weaker and that in squamous-cell carcinoma of the lung was weakest. Moreover, KDR was also weakly expressed in other cells, such as smooth muscle cells and interstitial cells. CONCLUSION: VEGF receptor is expressed not only in the endothelial cells of tumor vasculature, but also in tumor cells. Tumor cell expression of KDR varies in intensity with tumors of different origins. The possible significance of VEGF receptor expression with regard to tumor cell proliferation and metastasis is discussed.

Animals↗

[The effect of combined endocrine therapy on prostate and testis].

OBJECTIVE: To study the pathological changes of the effect of combined endocrine therapy on normal prostate, benign prostatic hyperplasia, prostatic adenocarcinoma and testis. METHODS: 11 radical prostatectomy specimens, 3 core-needle biopsies of prostate and 3 testes obtained after at least 3 months of enatone-flutamide inhibition therapy were studied. Step-section was performed on radical specimens and average 16 sections per case were reviewed. PSA, PSAP and AE1/AE3 were immunostained on 14 cases of prostate cancer and a comparative study pre- and post-treatment was made. RESULTS: No residual tumor was recognized in 2 cases. Such characteristic changes were found in 9 cases as prominent acinar atrophy, decreased ratio of acini to stroma, stromal fibrosis, squamous metaplasia of carcinoma, cytoplasmic vaculation, nuclear shrinkage, and nucleolar shrinkage. No apparent change was discovered in 3 cases. Secretory epithelial atrophy and basal cell hyperplasia were the popular change in BPH and normal prostate. The expressions of both PSA and PSAP were markedly reduced in prostate carcinoma and nonneoplastic glands. Pathological downstaging of the tumor was not found statistically. Epithelial atrophy also existed in seminal vesicles and Leydig cells of the testes after hormone therapy. CONCLUSIONS: Combined endocrine therapy results in histologically distinctive changes that can be found in both nonneoplastic and neoplastic prostate tissue. However, the drugs can not eradicate prostate cancer completely. Testis atrophy is the direct action of the therapy.

Aged↗

[Clinicopathologic study of 11 patients with Paget's disease of scrotum].

OBJECTIVE: To probe the relationship of clinicopathologic presentations and prognosis of Paget's disease primarily involving the scrotum. METHODS: 11 cases of scrotal Paget's disease were studied retrospectively from 1984 to 1997. PAS was stained and EMA, S-100, HMB45, CEA and CA15-3 were immunostained in all cases for the differential diagnosis from Bowen's disease and malignant melanoma. RESULTS: Six of 11 cases involved hair follicle and/or sweat glands, and 3 cases involved dermis (one had metastasis of left superficial and deep inguinal lymph nodes, and left internal iliac lymph nodes). Paget's cells were positive for PAS (11/11), EMA (11/11), CEA (6/11), CA15-3 (11/11), and negative for S-100, HMB45. Wide local excision of the lesions was performed in 10 of 11 patients both for primary disease and recurrent disease. 3 of the 10 patients underwent lymph nodes resection and metastasis was found in 1 case pathologically. One patient accepted chemotherapy and died, from respiratory insufficiency after one month. The other 10 patients were followed up for 6 to 127 months and no patient died of Paget's disease. CONCLUSIONS: Involvement of hair follicles and sweat glands by Paget's cell does not influence the prognosis.However, invasion of dermis by Paget's cells may suggest possible metastasis.

Aged↗

[Measurement of cyclosporine A in whole blood by high performance liquid chromatography(HPLC)].

Whole blood was extracted by ether under base using cyclosporine D as internal standard. The extraction was evaporated and reconstituted. The interferences were further removed by hexane. The reconstitution was injected into a C18 reversed-phase column at 70 degrees C, which was eluted with a mobile phase of acetonitrite/methanol/water(60/10/30, v/v) at flow rate 1.6 ml.min-1 and monitored at 210 nm. Three levels of BIO-RAD cyclosporine A(whole blood) calibrator were measured, all the results were within expected range. The detection limit was 25 ng.ml-1. The linearity was at least within 50-1,000 ng.ml-1. Analytical recoveries were 99.6%-108.8%. The within-run cv and between-run CV were 7.2% and 9.3%, respectively.

Chromatography, High Pressure Liquid↗

[Study on the steroid constituents of soft coral Lobophytum microspiculatum].

The soft coral Lobophytum microspiculatum collected from Xisa Islands of the South China Sea was immersed in and extracted with ethyl alcohol and the extract was concentrated, and then partitioned between ethyl acetate and water. The portion soluble in ethyl acetate was subjected to column chromatography over Sillca H, eluted with a step gradient of EtOAc and petroleum ether. The sterols were obtained from 20% EtOAc-petroleum ether eluent portion. By means of GC/MS method, the sterols were identified to be: cholesta-26-methyl-ol; ergosta-8, 22-dien-3 beta-ol, 24-methyl; ergosta-5, 22-dien-3 beta-ol, 23, 24-dimethyl; cholesta-5,22(23)-dien-3 beta-ol, 22,24-dimethyl; cholesterol; ergosta-5,22-dien-3 beta-ol, 24-methyl; ergosta-5,22-dien-3 beta-ol, 22,24-dimethyl, 24-methyl-cholesterol; ergosta-7-en-3 beta-ol, 24-methyl; nor-ergosta-7-en-3 beta-ol and gorgosterol. Among them cholest-5,22(23)-3 beta-ol, 22,24-dimethyl (4) is a new compound which was found at the first time from the nature. This finding gave a further prove for the biogenesis path way of gorgosterol.

Animals↗

[The effect of mobile phase on the enantiomeric separation of cyfluthrin by chiral high performance liquid chromatography].

The enantiomeric separation of cyfluthrin on chiral stationary phase(CSP), derived from (R)-N-(3,5-dinitrobenzoyl) phenylglycine (Prikle type 1-A CSP) has been studied by using different hexane-alcohol mixtures as mobile phase. Mobile phase strength and composition have shown an important role in the chromatographic separation of eight isomers of cyfluthrin. Increase of the mobile phase strength reduces the retention of the eight isomers, while the diastereomeric selectivity is decreased and the enantiomeric selectivity remains almost unchanged. Also, the resolution varies in accordance with the steric hindrance of the alcohol. Secondary or tertiary alcohols impart a greater resultion to the CSP than primary alcohols. Peak shapes are better with the lower alcohols than the higher alcohols. For the enantiomeric separation of cyfluthrin on Pirkle type 1-A CSP, hexane-tert-butanol and hexane-2-propanol are better binary mobile phases.

Chromatography, High Pressure Liquid↗

[Dynamic changes in IL-4, IL-5 and IL-10 in liver and bone marrow of mice infected with Schistosoma japonicum].

AIM: To observe the changes in Th2 cytokines in the liver and bone marrow of mice infected with schistosomiasis japonica. METHODS: ABC immunohistochemical staining technique and multimedia pathological picture analysis were used. Meanwhile, IL-4, IL-5 and IL-10 derived from livers and bone marrows of infected mice were observed at wk 8, 10 and 12 after infection. RESULTS AND CONCLUSION: In the livers of infected mice, the levels of IL-4, IL-5 and IL-10 increased obviously with a prolongation of the infection duration, IL-4 being the highest. However, in the bone marrow of infected mice, IL-4 level increased slowly with the duration of the infection, being lower than those in the liver at wk 10 and 12 after infection. The level of IL-5 was higher than that in the liver within 12 wk. At wk 10 after infection IL-10 tended to increase, but decreased thereafter and was obviously lower than that in the liver. In mice infected with Schistosoma japonicum, the immune response occurred mainly in the liver. IL-5 in the bone marrow showed auto-secretion.

Animals↗

[Changes in chloroquine resistance of Plasmodium falciparum in Hainan province].

AIM: To observe the variation in resistance of Plasmodium falciparum after the cessation of chloroquine medication. METHODS: WHO standard in vitro microtest and in vivo test were used. RESULTS: In vitro test showed that the rate of chloroquine-resistant P. falciparum dropped from 97.9% in 1981 to 26.7% in 1997 (P < 0.001). The mean concentration of chloroquine for complete inhibition of schizont formation declined from 10.46 +/- 7.14 pmol/ul blood in 1981 to 1.63 +/- 1.47 pmol/microliter blood in 1997(P < 0.001). In vivo test showed that the rate of chloroquine-resistant P. falciparum decreased from 84.2% in 1981 to 18.4% in 1997(P < 0.001). The proportion of R III cases to the total resistant cases dropped from 53.1% in 1981 to 14.3% in 1997. CONCLUSION: A tendency of progressive decline of resistance of the parasite was revealed after the cessation of chloroquine medication.

Adolescent↗

Stat3 plays an important role in oncogenic Ros- and insulin-like growth factor I receptor-induced anchorage-independent growth.

The role of signal transducers and activators of transcription (STATs) in receptor protein-tyrosine kinase (PTK)-induced cell growth and transformation was investigated using an inducible epidermal growth factor receptor-Ros chimeric receptor called ER2 and a constitutively activated insulin-like growth factor I receptor called NM1, both of which are able to induce anchorage-independent growth of NIH 3T3 cells. ER2 and NM1 receptor PTKs are able to cause Stat3 activation. Co-expressing the dominant negative Stat3 mutant with ER2 or NM1 in transiently or stable transfected cells resulted in a dramatic inhibition of colonies induced by these receptor PTKs and a moderate inhibition of their mitogenicity in monolayer. Therefore, Stat3 is not only important for initiation of transformation, as demonstrated by inhibition of the epidermal growth factor-inducible colony formation of the ER2 cells by the mutant, but it is also required for the maintenance of transformation, as evidenced by reversion of the NM1 transformed cells. The DNA binding and transcriptional activities of the endogenous Stat3 were greatly inhibited in the ER2 and NM1 cells co-expressing the Stat3 mutants. We conclude that activated function of Stat3 is required for the establishment and maintenance of Ros and insulin-like growth factor I receptor PTK-induced cell transformation.

3T3 Cells↗

Immune mediated and inherited defences against flaviviruses.

BACKGROUND: Flavivirus infection elicits an abundant immune response in the host which is directed against a number of the viral proteins. Resistance to flavivirus-induced disease can also be controlled via a non-immune mechanism involving the product of a naturally occurring murine gene, Flv. OBJECTIVES: To review studies that have reported the mapping of epitopes on flavivirus proteins that elicit T- or B-cell immune responses in mice or humans and to discuss a possible mechanism for flavivirus-specific genetic resistance. STUDY DESIGN: Purified viral proteins and synthetic peptides were used to map B-cell epitopes. Purified proteins, vaccinia-expressed viral protein fragments and synthetic peptides were used to map T-cell epitopes. Congenic-resistant, C3H/RV and congenic susceptible, C3H/He mice and cell cultures were used to study the mechanism of genetic resistance to flavivirus infection. RESULTS: T- and B-cell epitopes have been mapped to the E, NS1 and NS3 proteins of several flaviviruses. Immune responses to the C, PreM, NS2a, NS4a, and NS5 proteins have also been documented. Data suggest that the Flv gene product acts intracellularly to suppress the synthesis of viral genomic RNA. CONCLUSIONS: Although flavivirus infection elicits an abundant immune response, this response is not always rapid enough to protect the host from developing encephalitis. During secondary infections both the humoral and cellular flavivirus-specific responses can confer protection. Dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS) appear to be caused by an overly vigorous immune response. In genetically resistant animals reduced production of virus results in a slower spread of the infection, which in turn allows time for the immune response to develop and to clear the infection before disease symptoms appear.

Animals↗

Characterizing semilocal motions in proteins by NMR relaxation studies.

The understanding of protein function is incomplete without the study of protein dynamics. NMR spectroscopy is valuable for probing nanosecond and picosecond dynamics via relaxation studies. The use of 15N relaxation to study backbone dynamics has become virtually standard. Here, we propose to measure the relaxation of additional nuclei on each peptide plane allowing for the observation of anisotropic local motions. This allows the nature of local motions to be characterized in proteins. As an example, semilocal rotational motion was detected for part of a helix of the protein Escherichia coli flavodoxin.

Escherichia coli↗

An in vitro model of human red blood cell production from hematopoietic progenitor cells.

Hemoglobinopathies, such as beta-thalassemias and sickle cell anemia (SCA), are among the most common inherited gene defects. Novel models of human erythropoiesis that result in terminally differentiated red blood cells (RBCs) would be able to address the pathophysiological abnormalities in erythrocytes in congenital RBC disorders and to test the potential of reversing these problems by gene therapy. We have developed an in vitro model of production of human RBCs from normal CD34(+) hematopoietic progenitor cells, using recombinant growth factors to promote terminal RBC differentiation. Enucleated RBCs were then isolated to a pure population by flow cytometry in sufficient numbers for physiological studies. Morphologically, the RBCs derived in vitro ranged from early polylobulated forms, resembling normal reticulocytes to smooth biconcave discocytes. The hemoglobin pattern in the in vitro-derived RBCs mimicked the in vivo adult or postnatal pattern of beta-globin production, with negligible gamma-globin synthesis. To test the gene therapy potential using this model, CD34(+) cells were genetically marked with a retroviral vector carrying a cell-surface reporter. Gene transfer into CD34(+) cells followed by erythroid differentiation resulted in expression of the marker gene on the surface of the enucleated RBC progeny. This model of human erythropoiesis will allow studies on pathophysiology of congenital RBC disorders and test effective therapeutic strategies.

Adult↗

Definition of an epitope on NS3 recognized by human CD4+ cytotoxic T lymphocyte clones cross-reactive for dengue virus types 2, 3, and 4.

The role of dengue virus-specific serotype-cross-reactive T lymphocytes in recovery from and pathogenesis of dengue virus infections is not known. In the present paper, we have defined a dengue serotype-cross-reactive epitope recognized by two CD4+ CD8- cytotoxic T lymphocyte (CTL) clones, JK36 and JK46. These T cell clones were established from the peripheral blood T lymphocytes of a dengue-3-immune donor, using a limiting dilution method. JK36 and JK46 were cross-reactive for dengue virus types 2, 3, and 4, but not for type 1, and recognized the NS3 protein. The smallest synthetic peptide recognized by JK36 was an 8-amino acid peptide that contains amino acids (aa) 226 to 233 (VVAAEMEE) of NS3. The smallest peptide recognized by JK46 was an 11-amino acid peptide that contains aa 224 to 234 (TRVVAAEMEEA). HLA-DR15 was the restriction allele for recognition of these peptides by both JK36 and JK46. This is the first epitope to be defined that is recognized by human CD4+ CTL cross-reactive for dengue virus types 2, 3, and 4.

Amino Acid Sequence↗

Muricoreacin and murihexocin C, mono-tetrahydrofuran acetogenins, from the leaves of Annona muricata.

Bioactivity-directed fractionation of the leaves of Annona muricata L. (Annonaceae) resulted in the isolation of two new Annonaceous acetogenins, muricoreacin (1) and murihexocin C (2). Compounds 1 and 2 showed significant cytotoxicities among six human tumor cell lines with selectivities to the prostate adenocarcinoma (PC-3) and pancreatic carcinoma (PACA-2) cell lines.

4-Butyrolactone↗