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Biomedical subjects

Y Qin

Publications and source records attributed to Y Qin.

At least 91 records · Page 5Linked to original sources
PubMed1998

[Mutation analysis of the p15 gene exon 2 in human primary hepatocarcinoma].

To investigate the role p15 gene plays in the pathogenesis of human primary hepatocarcinoma, 35 human hepatocarcinomas, 35 cases of adjacent non-cancerous liver cirrhosis and the blood cells of 10 normal human were analyzed for somatic mutation in p15 gene with PCR-SSCP. One case of adjacent non-cancerous liver cirrhosis showed abnormal migration single strand. In the hepatocarcinomas and in the other cases of adjacent non-cancerous liver cirrhosis, no mutation was found. Cloning and sequencing of the amplified abnormal migration single strand DNA revealed that it contained a wild type exon 2 of p15 gene in 345 bp length. The results indicate that the inaction of p15 gene by point mutation is a very uncommon event in human hepatocarcinoma.

Carcinoma, Hepatocellular↗
PubMed1998

[Slot blot analysis of metastasis suppression gene nm23 expression in human lung cancer].

To investigate the role of metastasis suppression gene (nm23) in the development and progression of human lung cancer, the mRNA expressions of nm23-H1 and nm23-H2 genes in a series of pulmonary tissues collected at various sites and with different properties were studied with slot blot hybridization. According to the observations on the normal pulmonary tissues, benign lesions, para- and non-cancer tissues, primary cancer and metastatic lymph nodes, there was a tendency of mRNA expression reduction of nm23-H1 and nm23-H2 genes. Among them, nm23-H2 mRNA expressions in lung cancer tissues were significantly decreased when compared with normal pulmonary tissues (P < 0.05), and nm23-H1 and nm23-H2 gene expressions in metastatic lymph nodes were both reduced, compared with those in normal pulmonary tissues (P < 0.05). There was no significant correlation between nm23 gene expression and lymph node metastasis in lung cancer. The results implied that reduction of nm23 gene expression might be associated with the development of lung cancer, but no evidence of metastasis suppression by nm23 gene was revealed in this study.

Adenocarcinoma↗
PubMed1998

[Northern blot analysis of nm23 gene expression in human lung cancer].

OBJECTIVE: To investigate the role of nm23 gene expression in lung cancer. METHODS: Forty human lung cancer tissues and 19 non-cancerous pulmonary tissues were studied for their nm23-H1 and nm23-H2 mRNA expression with nonradioactive Northern blot hybridization. Correlation of nm23 mRNA expression with clinical features of lung cancer was analyzed. RESULTS: The mRNA expression of nm23-H2 gene in poorly differentiated squamous-cell carcinoma was significantly decreased compared to that in moderately differentiated squamous-cell carcinoma. The mRNA expression of nm23-H1 and nm23-H2 genes in small cell lung cancer was decreased compared to that in squamous-cell carcinoma. No significant difference in nm23 mRNA expression was observed in lung cancers with and without lymph node metastasis, nor was there significant difference in patients with lung cancers in different stages. CONCLUSION: The mRNA expression of nm23 gene is correlated with the degree of differentiation of lung cancer, but there is no evidence of metastasis suppression effect by nm23 gene.

Adenocarcinoma↗
PubMed1998

[Expression of nm23 in gastrointestinal smooth muscle tumors and its relation to cell proliferative activity].

OBJECTIVE: To determine the relationship between nm23 expression and benign or malignant degree, metastasis, prognosis and cell proliferative activity of gastrointestinal smooth muscle tumors (GISMT). METHOD: 86 cases of GISMT were studied, and nm23 was detected by the immunohistochemical staining S-P method. The cell proliferative activity was evaluated by the silver colloid method for argyrophilic nucleolar organizer regions proteins (AgNORs) and by the immunohistochemical staining S-P method for proliferating cell nuclear antigen (PCNA). RESULT: The expression of nm23 declined significantly according to the following order: leiomyomas, low malignant leiomyosarcomas, high malignant leiomyosarcomas (P < 0.01). The expression of nm23 was associated with the tumors with or without contiguous organ invasion or distant metastasis, the size of tumors, the tumors with or without center necrosis (P < 0.01 or P < 0.05). The five-year survival rate was significantly higher in patients with nm23 positive expression than that with nm23 negative expression (P < 0.05). The expression of AgNORs and PCNA with nm23 negative cases was obviously higher than that with nm23 positive cases (P < 0.01). CONCLUSION: nm23 is a valuable indicator for the biological characteristics of GISMT. nm23 expression and cell proliferative activity can supply a deficiency each other in distinguishing malignant from benign tumors, judging the malignant degree, and predicting the prognosis of the patients with GISMT.

Adolescent↗
PubMed1998

[Study on the polyoxygenated cyclohexenes from Uvaria boniana].

Seven new polyoxygenated cyclohexenes, named uvaribonol A-G (1-7) have been isolated from the ethanol extract of the stems of Uvaria boniana Finet. (Annonaceae), and their structures, including the absolute configuration, were determined by spectral and chemical methods. In vitro cytotoxicity test against several human tumor cell lines indicated that all of the new natural compounds are inactive, but some of the derivatives showed obvious activities. Compound 2a is the most active, exhibiting significant cytotoxicities against KB and Bel7402 cells with IC50 < 1 microgram.ml-1, and against HCT-8 cell with IC50 < 0.1 microgram.ml-1.

Annonaceae↗
PubMed1998

[luxAB genes as marker for detecting Rhizobium fredii HN01 nodulation functions].

A suicide plasmid pHNC3 which contains Tn5-luxAB was transferred into Rhizobium fredii HN01 by the help of pRK2013. Then Tn5-luxAB inserted on the genome of HN01 and gave luminescence activity. The luminescence colonies were picked up and the Eckhardt gel was performed for plasmids profile detection. The location of Tn5-luxAB on the genome was determined using the luxAB as probe. The colonies which were marked by Tn5-luxAB on the chromosome and different plasmids of HN01 were chosen for pot experiment, and a chromosome labelled strain HN01LC02 was detected by soil pot experiment. The detections included the nodulation occupancy and the luminescent nodules distribution on the root system formed by the luxAB-marked rhizobia.

Chromosomes, Bacterial↗
PubMed1998

[Comparative research on two different killer strains of Saccharomyces cerevisiae].

Using two different killer strains SK4(K1 type) and ERR1(K2 type), their killer characters were analysed and find two strains compete with each other when they are mixed and killer characters are related with the growth of strains. Different M-dsRNA plasmids in different killer strains have different molecular lengths, being 1.7 kb and 1.5 kb in SK4 and ERR1, respectively. L-dsRNA plasmids in both strains have the same molecular lengths, 4.0 kb. Cured by high temperature (38 degrees C) and U.V. (15 W, 30 cm, 5 min), killer strains lose their killer characters with the disappearance of M-dsRNA, the curing rate of killer activity is associated with strains and curing conditions. Killer toxins produced by two strains have different killer effects. Toxins of SK4 and ERR1 have the different highest killer activity at pH 4.8, 16 degrees C and pH4.2, 22 degrees C, but both of two toxins have the greatest effect on the sensitive strain in the late-log phase.

Hydrogen-Ion Concentration↗
PubMed1998

Sequence and structural analysis of feline interleukin-5 cDNA.

OBJECTIVE: To clone and characterize the cDNA encoding feline interleukin-5 (IL-5) cDNA and the 170 basepairs (bp) of the 5' flanking region of the feline IL-5 gene. SAMPLE POPULATION: Blood mononuclear cells from a healthy cat. PROCEDURES: Cells were cultured, stimulated for 48 hours with concanavalin A, and harvested for RNA and DNA isolation. Recovered RNA was used in northern blot and reverse transcription-polymerase chain reaction analyses. Resulting cDNA was used for rapid amplification of 3' cDNA ends, dideoxy chain termination sequencing, and primer extension analysis. RESULTS: Full length cDNA was 838 bp, including a 402-bp open reading frame that encoded a precursor protein of 134 amino acids including a putative peptide signal of 19 residues. Homologies of the nucleotide and derived protein sequences between feline and human IL-5 cDNA were 72 and 71%, respectively. There also was homology between the human and predicted feline cytokines at amino acid positions that are critical for IL-5 receptor binding and signal transduction. The 5' flanking region of the feline gene was homologous to corresponding regions of the human (88%) and murine (72%) genes, and included putative transcriptional regulatory elements. CONCLUSIONS AND CLINICAL RELEVANCE: Identification of feline IL-5 cDNA is an important step toward a detailed, fully comprehensive characterization of the mechanisms that may be operative in the pathogenesis of eosinophilic disorders in cats. The striking homology between the human and feline IL-5 genes suggests that cats can be used as animal models for human diseases characterized by eosinophil infiltration of tissues.

Amino Acid Sequence↗
PubMed1997

[Preparation method of foamed aerosol for use in vagina].

The extraction of medicinal materials, compatibility of liquor and prescription of emulsion for use in vagina were observed. The result shows that through compound extraction, removal of tannic materials, decolorization and water precipitation, with propylene glycol and ethylene glycol as latent solvent and using lactic acid to adjust to pH4.5, a clarified solution can be obtained, and then with the help of Tween-spans emulisifying agent and propellant the stable emulsion is formed.

Administration, Intravaginal↗
PubMed1997

[Histopathological studies of laryngeal allotransplantation in rats].

The establishment of an animal model for laryngeal allotransplantation in rat has enabled us to correlate clinical impressions of laryngeal allograft rejection with histologic data. In this study we used both clinical and histopathologic criteria to define the sequence and time parameters of rejection in histoincompatible vascularized rat laryngeal allografts. Of the 31 rats receiving vascularized laryngeal allografts, 18 served as experimental group, in which allogeneic transplantations were performed from inbred SD to outbred Wistar rats, 13 rats used as controls receiving laryngeal histocompatible transplants. The clinical phenomena of rejection aas started at 3 days post-operation, characterized by noticeable dermal swelling and lymphadenectasis of the recipient's neck. At this time, the graft appeared slightly edematous. These changes progressed and were more pronounced by 1 week. Two weeks after operation, the recipients exhibited an inflammatory scar tissue encasing the graft, the normal laryngeal architecture of grafts was invisible. Gross clinical evidence of rejection was well correlated with pathologic findings. Three days following transplantation, there was a slight histologic difference between the experimental group and the control group. Five days later, the surface respiratory epithelium exhibited progressive squamoi metaplasia, and minor salivary glands were mostly atrophic, afterwards extensive loss of acini emerged, with predominant lymphocyte and polymorphonuclear leukocyte infiltration throughout the lamina propria, sub-mucosa and the laryngeal adventitia. The arteriolar walls showed fibrinoid changes, with reactive intimal proliferation, and thickening of vessel wall. Focal thrombosis were frequently found. By 2 weeks, the normal architecture of the laryngeal allografts had nearly completely been replaced by fibrovascular connective and granulation tissues. Definition of the time sequence and histopathology of rejection will allow future determination of the efficacy of various immunosuppressive agents.

Animals↗
PubMed1997

Intraclonal offspring expansion of gastric low-grade MALT-type lymphoma: evidence for the role of antigen-driven high-affinity mutation in lymphomagenesis.

Recent studies have shown that gastric mucosa-associated lymphoid tissue (MALT)-type lymphoma B cells are the malignant counterparts of hypermutated, postgerminal-center memory B cells. To further elucidate the role of antigen selection in the evolution of gastric low-grade MALT-type lymphoma, we analyzed intraclonal variations of the immunoglobulin heavy-chain variable region (Ig VH) genes expressed in three cases of lymphoma. The Ig VH genes expressed by tumor cells were amplified by PCR using primers for individual tumor-specific markers (complementarity-determining region 3 (CDR3)) and primers for six VH family leaders and then sequenced. The corresponding germ-line VH gene from these patients was also sequenced. The somatic mutations were highly concentrated in the CDR or framework region, with a clustering of replacement mutations in the CDR but only a few in the framework region. Each of the Ig VH genes of tumor cell clones of Cases 1 and 3 showed different mutations, whereas Case 2 showed no intraclonal variation. Although all three mutation pattern variants of Cases 1 and 3 occurred in postgerminal memory B cells, only one offspring from each case resulted in a dominant expansion. This finding suggests that antigen-driven high-affinity somatic mutation may play an important role in the expansion of intraclonal offspring from low-grade MALT-type lymphomas.

Base Sequence↗
PubMed1997

Low-grade B cell lymphomas of mucosa-associated lymphoid tissue (MALT-type) require CD40-mediated signaling and Th2-type cytokines for in vitro growth and differentiation.

To investigate the mechanisms of T cell dependence underlying the development of extranodal mucosa-associated lymphoid tissue (MALT)-type B cell lymphomas, the activation, proliferation, and differentiation of lymphoma B cells were studied using ligand binding to the CD40 membrane receptor. The activation and proliferative response of all investigated low-grade MALT-type lymphomas (n = 6) was strongly dependent on anti-CD40-mediated signals and was complemented by cytokines produced by T helper cells of the Th2 type (interleukin-4 (IL-4) and/or IL-10). Th1 cytokines (IL-2 and/or interferon-gamma) bad little effect. Low-grade, but less so high-grade, MALT-type lymphoma B cells were induced to secrete large amounts of tumor immunoglobulin in response to IL-10. In contrast, high-grade MALT-type lymphomas (n = 5) proliferated in response to both Th2- and Th1-type cytokines and CD40 stimulation, whereas Burkitt lymphomas (n = 3) could not be rescued from apoptosis by CD40 stimulation with or without cytokines. These results suggest that CD40 signaling in combination with Th2 cytokines are essential for the development and progression of low-grade MALT-type B cell lymphoma. We conclude that T cells, which activate B cells in a CD40-dependent fashion, may contribute to lymphoma pathogenesis.

B-Lymphocyte Subsets↗
PubMed1996

Mechanical strain induces pp60src activation and translocation to cytoskeleton in fetal rat lung cells.

We have previously shown that mechanical strain-induced fetal rat lung cell proliferation is transduced via the phospholipase C-gamma-protein kinase C pathway. In the present study, we found that protein-tyrosine kinase activity of fetal lung cells increased after a short period of strain, which was accompanied by tyrosine phosphorylation of proteins of approximately 110-130 kDa. Several components of this complex were identified as pp60srcsubstrates. Strain increased pp60src activity in the cytoskeletal fraction, which coincided with a shift in subcellular distribution of pp60src from the Triton-soluble to the cytoskeletal fraction. Strain-induced pp60src translocation did not appear to be mediated via the focal adhesion kinase-paxillin pathway. In contrast, strain increased the association between pp60src and the actin filament-associated protein of 110 kDa. Preincubation of cells with herbimycin A, a tyrosine kinase inhibitor, abolished strain-induced phospholipase C-gamma1 tyrosine phosphorylation and its coimmunoprecipitation with pp60src. It also inhibited strain-induced DNA synthesis. These results suggest that activation of pp60src is an upstream event of the phospholipase C-gamma-protein kinase C pathway that may represent an important mechanism by which mechanical perturbations are converted to biological reactions in fetal lung cells.

Animals↗
PubMed1996

Developmental shift of myosin heavy chain mRNA expression due to neural factor(s) and muscle activity.

The adult ventricular isoform of chicken myosin heavy chain (MHC-V) is transiently expressed in all skeletal muscle primordia analyzed and is completely repressed around embryonic days 10-12, when functional innervation is established. By ribonuclease protection assay, we demonstrated that denervation of the adult anterior latissimus dorsi muscle resulted in reexpression of MHC-V mRNA. In contrast, treatment of primary cultures of fetal breast or leg muscles with embryonic brain extract or conditioned media from glial or neuroblastoma cell lines, but not from a myogenic cell line or primary muscle cell cultures, led to inhibition of MHC-V expression. This inhibitory activity was abolished by heating and increased with protein concentration. The acquisition of both brain inhibitory activity and the competence of myogenic cells to downregulate MHC-V mRNA expression were age dependent. Furthermore, either paralysis of muscle in ovo by curare or contraction arrest of cultured myotubes resulted in persistent expression of MHC-V mRNA. Thus a putative soluble factor(s) of nerve origin as well as muscle activity are involved in the developmental downregulation of MHC-V expression in muscle primordia.

Age Factors↗
PubMed1996

Prevention of trauma-induced neurodegeneration in infant rat brain.

Recent evidence implicates the endogenous excitatory neurotransmitters, glutamate (Glu) and aspartate, in the pathophysiology of traumatic injury in the adult CNS, but it is not known whether similar excitotoxic mechanisms mediate traumatic injury in the immature CNS. Therefore, we developed a model of brain contusion injury in infant rats and used this model to study the nature and evolution of the acute cytopathologic changes and to evaluate the ability of Glu receptor antagonists to protect the immature brain against such changes. Seven-day-old rat pups were subjected to contusion injury and were killed 0, 0.5, 1, 2, 4, and 6 h later for histologic evaluation of the brain. Physical tearing of the dura and minor disruption of underlying brain tissue was noted at 0 h. At 30 min a discrete zone of neuronal necrosis began to appear at the border of the trauma site; this zone progressively expanded over a period of 4 h. The cytopathologic changes closely resembled the type of changes Glu is known to cause; these changes consisted of swollen dendrites, degenerating neurons with pyknotic nuclei and markedly swollen cytoplasm, and dark cells with vacuolated cytoplasm. The noncompetitive N-methyl-D-aspartate (NMDA) antagonist, dizocilpine maleate, when administered 30 min before or 1 h after trauma, significantly attenuated the lesion. The competitive NMDA antagonist, 3-((-2)-carboxypiperazine-4-yl)-propyl-1-phosphonate, was also neuroprotective. The alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate/kainate receptor antagonist 2,3-dihydro-6-nitro-7-sulfamoyl-benzo(f)quinoxaline did not significantly suppress the lesion when given as three treatments (30 mg/kg each) 30 min before plus 15 and 75 min after the insult. These findings suggest that traumatic injury in the infant rat brain is mediated by endogenous excitotoxins (Glu and aspartate) acting at NMDA receptors and can be substantially mitigated by timely treatment with NMDA receptor antagonists.

Animals↗
PubMed1996

Deciphering the hippocampal polyglot: the hippocampus as a path integration system.

Hippocampal 'place' cells and the head-direction cells of the dorsal presubiculum and related neocortical and thalamic areas appear to be part of a preconfigured network that generates an abstract internal representation of two-dimensional space whose metric is self-motion. It appears that viewpoint-specific visual information (e.g. landmarks) becomes secondarily bound to this structure by associative learning. These associations between landmarks and the preconfigured path integrator serve to set the origin for path integration and to correct for cumulative error. In the absence of familiar landmarks, or in darkness without a prior spatial reference, the system appears to adopt an initial reference for path integration independently of external cues. A hypothesis of how the path integration system may operate at the neuronal level is proposed.

Animals↗