Biomedical subjects

Y Cai

Publications and source records attributed to Y Cai.

At least 145 records · Page 8Linked to original sources

PubMed1999

[DNA damage in human peripheral blood lymphocyte caused by nickel and cadmium].

OBJECTIVE: To understand the different implication of various forms of DNA damage in genotoxicity of nickel and cadmium. METHODS: Human peripheral lymphocyte was exposed to nickel chloride and cadmium chloride in vitro. Levels of DNA single-and double-strand breaks and DNA-protein crosslinks in human peripheral lymphocyte were determined with single cell gel electrophoresis (SCGE). Activity of poly (ADP-ribose) polymerase (PARP) was determined by [(3)H]-NAD incorporating method. RESULTS: Levels of DNA single-and double-strand breaks and DNA-protein crosslinks in human peripheral lymphocyte treated with nickel and cadmium were significantly higher than those untreated, but dose-response relationship only showed in those treated with 0.10 - 10.00 micromol/L of nickel chloride and 0.16 - 20.00 micromol/L of cadmium. Low levels of the two kinds of metal (0.10 - 0.40 micromol/L of nickel and 0.16 micromol/L of cadmium) could induce the cleavage of DNA and activate PARP, and high levels of the two kinds of metal (2.00 - 10.00 micromol/L of nickel and 0.80 - 20.00 micromol/L of cadmium) could not induce the enzyme cleavage of DNA. CONCLUSION: Formation and cleavage of DNA double strand and blockage of activation of PARP can play an important role in carcinogenesis and mutagenesis.

Cadmium Chloride↗

PubMed1999

[Studies on Chinese drugs zhiqiao and zhishi origin investigation and merchandise identification].

OBJECTIVE: To sort out the main original plants of Chinese drugs Zhiqiao and Zhishi. METHOD: Investigating the medicinal plant resources in the growing area and conducting morphological identification of more than 40 pieces of these two commercial drugs. RESULT: A taxonomic table, a distribution table and a commercial drug identification table are given. CONVLUSION: The Chinese medicinal plants Zhiqiao and Zhishi originated from Citrus aurantium and its varieties C. aurantium "Xiucheng", C. aurantium "Xiangcheng" and Poncirus trifoliata x C. aurantium, some other plants from Citrus genus and Poncirus trifoliata are taken as the origin of Zhiqiao and Zhishi only in a few areas.

China↗

PubMed1999

[Clinical usefulness of serum IFN-gamma level in patients with chronic obstructive pulmonary disease].

The objective of this study was to gain a clear idea of rule of change in serum IFN-gamma level in patients with chronic obstructive pulmonary disease and to evaluate the clinical usefulness of IFN-gamma as a marker of immune condition. The serum IFN-gamma levels of 15 patients with chronic bronchitis, 15 patients with cor pulmonale, 15 patients with acute bronchitis, and 15 normal subjects were measured by radio-immuno-assay. Differences between the four groups were tested, and in the chronic bronchitis group, the serum IFN-gamma levels, before and after treatment were compared. The results showed that compared with the normal group (0.8 +/- 0.17 IU/ml), the serum level changed little in the cor pulmonale group (0.93 +/- 0.25 IU/ml); it was not higher in the chronic bronchitis group (1.23 +/- 0.39 IU/ml, P > 0.05), but it went up significantly after treatment for 7 days (1.84 +/- 0.51 IU/ml, P < 0.05). The highest level of IFN-gamma was noted in the acute bronchitis group (2.24 +/- 0.71 IU/ml, P < 0.01). There was a significant difference compared with other groups (P < 0.01). These results suggest that relative deficiency of serum IFN-gamma may be a factor inducing repeated respiratory infection, and the serum level of IFN-gamma can be used as an index to assess the immune condition of patients with chronic obstructive pulmonary disease.

Biomarkers↗

PubMed1999

[An immunohistochemical and morphometric study of myoepithelial cells in salivary glands of human and experimental animals].

OBJECTIVE: To investigate whether differences exist between myoepithelial cells of human beings and experimental animals. METHODS: Myoepithelial cells(MeCs) of 8 kinds of experimental animals were studied immunohistochemically using muscle-acting-specific monoclonal antibody HHF35 and morphometrically using image-analysis. RESULTS: There were differences in mean proportional volumes of MeCs between human beings and experimental animals. The mean proportional volumes of mucous acini were more than those of serous acini except salivary glands of rodents. CONCLUSION: The mean proportional volume of MeCs in salivary glands associates with animal species and secretion of salivary glands.

Animals↗

PubMed1999

[Expression detection and location analysis of BstNI isoschizomer restriction-modification system gene].

Some genetic markers of E. coli HB101 and JM110 were identified, two bacterial strains were used as recipients respectively to detect the expression of a restriction endonuclease(R) gene and a methylase(M) gene of BstNI isoschizomer restriction-modification system. DNA fragment containing the R-M genes was deleted unilaterally with exoIII and 23 deletion subclones were obtained. According to the Enzyme activity of each subclone, R and M gene were located respectively at the regions of 0.2-->1.4 kb and 1.5-->3.3 kb from cloning site PstI. Analysis showed that the R. M system belongs to type II, two genes are controlled by the different promoters; the recognition sequence of this system is the same as that of DNA-cytosine methyltransferase(Dcm), the latter's methylation function can resist the R enzyme. It was interesting that the recombinant plasmid with an R+ M- genotype appeared to be lethal to dcm+ hosts yet. This indicated that the M gene closely linking to R gene is of critical importance for the existence of the R-M system in process of evolution.

Chromosome Mapping↗

PubMed1999

[Expression of Schistosoma japonicun fatty acid binding protein gene in silkworm cells and larvae].

AIM: To express the fatty acid binding protein (Sj14FABP) gene of Schistosoma japonicun in the silkworm cells and larvae. METHODS: A 600 bp DNA fragment containing Sj14FABP gene was cloned into baculovirus transfer vector of pBacPAK His1 to construct recombinant transfer vector Sj14-pBac PAK His1. Coinfection was accomplished with this vector and Bombyx mori nuclear polyhedrosis virus (BmNPV) DNA in BmN cells. The recombinant virus of Bm-Sj14 was screened using dot-blotting. The BmN cells and silkworm larvae were infected with Bm-Sj14 to express Sj14FABF gene. Western blotting and ELISA were used to identify the antigenicity of the recombinant protein. RESULTS: Sj14FABP gene was successfully expressed in the BmN cells and silkworm larvae infected with Bm-Sj14. The product was a 18 kDa fusion protein. The yield in BmN cells was about 100 micrograms/1 x 10(6) cells and 33 micrograms/ml cell supernatant. In silkworm larvae, the product yield was 4 mg/ml haemolymph as well as 4.6 mg/g silkworm tissue. The recombinant protein could be recognized by Western blotting and ELISA using the sera from mice immunized with SWAP. CONCLUSION: Sj14FABP gene has been successfully expressed in BmNPV system and the product has high antigenicity.

Animals↗

PubMed1999

[Safety analysis of dust mite allergen for diagnosis and immunotherapy of asthma and rhinitis].

AIM: To make a retrieval investigation of safety in using Dermatophagoides farinae extract in diagnosis and immunotherapy with patients of asthma and rhinitis. METHODS: A questionnaire evaluation of the safety use of D. farinae extract (SMU-Df) during diagnosis and immunotherapy of patients from 1974 to 1995 was carried out. RESULTS: A total of 8,46,342 injections were statistically analysed, among whom 142 systemic adverse reactions occurred involving urticaria 0.82@10000, severe attack of asthma 0.77@10000, anaphylactic shock 0.07@10000 (CL = 1.4-12.0/million), and angioedma 0.02@10000. The time of onset of systemic reactions of immediate type was < 30 min in 32 cases-times, and 1 h and 2 h in 6 cases-times; the time to onset of late response type was 3 h-48 h in 23 cases-times with highest incidence of severe asthmatic attacks. The systemic reactions occurred in 18 subjects during skin test, in 96 cases-times during increasing dose phase, and in 14 cases-times during. Among them 6 cases were of anaphylactic shock, and none of it after emergency treatment. The major cause of manifestation of systemic reactions for 41 cases after immunotherapy with SMU-Df extract was due to over dosage errors. CONCLUSION: The application of SMU-Df extract in skin test and immunotherapy of asthma and rhinitis sensitive to mite for the past 22 years in this country indicated that the efficacy and safety have been high.

Allergens↗

PubMed1999

[Experimental study on antitumor activity of the root of Eurphorbia helioscopia in vivo].

Previous studies showed EWE could strongly inhibit the proliferation of tumor cells in vivo. Experimental results also showed that EWE had antitumor effect in S180-bearing mice and H22-bearing mice and prolonged life-span in S180-bearing mice in this paper, Furthermore, it was found that EWE could improve the immune function of S180-bearing mice. Therefore EWE can be considered as a potent antitumor herb.

Animals↗

PubMed1999

[Studies on polysaccharides from Holothuria leucospilota].

A powder was obtained from the dried body of Holothuria leucosilota (Brandt). According to IR and UV spectra, paper chromatography and the physical and chemical data, it is showed a sulfated mucopoly-saccharide consisted of galactosamine, glucouronic acid, fucose and sulfate with the molar ratio of 1:0.96:0.78:1.98 respectively. The specific rotation, intrinsic viscoslty and molecular weight of this polysaccharide were all presented.

Animals↗

PubMed1999

[Antitumor activity of the root of Euphorbia helioscopic in vitro].

Antitumor activity of the aquatic extract the root of Euphorbia helioscopia L (EWE) in Vitro were studied. Viable cells count, MTT staining and colonal formation assays of three kinds of cancer cells were used to assess the antitumor activity. Determined by viable cells count, the IC50 values of EWE against 7721, Hela, MKN-45 cells were 1.26, 1.98, 1.72 mg/ml respectively (72 h). Determined MTT staining, the IC50 values EWE against 7721, Hela, MKN-45 cells were 1.43, 1.67, 0.97 mg/ml. Determined by colonal formation, the inhibition rate of EWE (4 mg/ml) against 7721, Hela, MKN-45 cells were 59.8%, 66.4%, 70.5%. The results indicated that EWE had obvious antitumor activity.

Antineoplastic Agents, Phytogenic↗

PubMed1999

[Histological identification of Chinese drug zhiqiao & zhishi].

After growing area investigating which covered 10 Provinces (or Cities) of China, we gathered 11 types Zhiqiao and 6 types Zhishi which consistently came from 12 species (or varieties). Histological studies on them have been taken. microscopical characters including transverse section and powder were described. These studies will provide scientific basis for the identification of Zhiqiao and Zhishi.

Citrus↗

PubMed1999

[The extracting of left ventricular contour based on adaptive directional filter].

This paper proposes the adaptive directional filter, which is exploited for the extracting of left ventricular(LV) contour. This algorithm could produce the exact ridge point by applying directional filter with smoothing operator in the angiography images damaged by noise the Edge Directional Vector as the result of this filter is efficient for predicting the edge ahead, while the filter parameters is adaptive. This proposed method provides the more precise and more automatic--extracting LV contour only with fewer interactions. The experimental results show that this proposed algorithm could improve the accuracy and reproducibility, and reduce the computational consumption remarkably.

Algorithms↗

PubMed1998

Homology-based gene prediction using neural nets.

We have developed and implemented a method for computational gene identification called GIN (gene identification using neural nets and homology information) that has been particularly designed to avoid false positive predictions. It thus predicts 55% of all genes tested correctly, has a specificity of 99%, but also has an overall accuracy of 92% on a benchmark set of 570 vertebrate genes constructed by Burset and Guigo. The method combines homology searches in protein and expressed sequence tag databases with several neural networks designed to recognize start codons, Poly(A) signals, stop codons, and splice sites. Predicted exons are assembled into genes using a homology-based scoring function. GIN is able to recognize multiple genes within genomic DNA as demonstrated by the identification of a globin gene (gamma-globin-1(G)) that has not been annotated as a coding region in the widely used the test set of Burset and Guigo. Furthermore, GIN identifies more than 107 other protein hits in noncoding regions and classifies them into possible pseudogenes or splice variants.

Animals↗

PubMed1998

Identification of PKD2L, a human PKD2-related gene: tissue-specific expression and mapping to chromosome 10q25.

Mutations in PKD2 cause autosomal dominant kidney disease (ADPKD). Polycystin-2, the PKD2 gene product, is an integral membrane glycoprotein of unknown function. We have identified PKD2L, another member of the PKD2 gene family. PKD2L is expressed in adult heart and skeletal muscle, brain, spleen, testis, and retina, and alternative transcripts of 2.4, 2.7, and 3.0 kb are seen. PKD2L shows 56% identity and 76% similarity with polycystin-2 over a 581-amino-acid span; however, the COOH-terminal 65 residues of PKD2L are unrelated to PKD2. PKD2L is localized to chromosome 10q25 and is excluded as a candidate gene for autosomal recessive polycystic kidney disease, autosomal dominant polycystic liver disease, and the third form of ADPKD. Given the high degree of homology between PKD2L and PKD2, it is likely that the respective functions of these proteins are also closely related.

Amino Acid Sequence↗

PubMed1998

Retinoic acid mediates down-regulation of the alpha-fetoprotein gene through decreased expression of hepatocyte nuclear factors.

alpha-Fetoprotein (AFP), a protein highly induced during fetal liver development, is down-regulated by retinoids in the human hepatoma cell line Hep3B, in contrast to up-regulation observed in other cell types. Previously, we have documented that such up-regulation involves direct effects through cis-retinoid X receptor-binding sites in the AFP enhancer. In this report, we show a distinctive effect of all-trans-retinoic acid (RA) in Hep3B cells. RA caused a marked decrease in AFP transcripts. Deletion analysis of the upstream regulatory region of the AFP gene revealed that cis-acting sites required for down-regulation resided near the promoter. Gel mobility shift assays for factors binding to key elements in the AFP promoter region demonstrated that hepatocyte nuclear factor (HNF) 1 binding was diminished in nuclear extracts from RA-treated cells. In addition, HNF4, which is not known to bind to the AFP promoter but does regulate HNF1, was also diminished. The levels of HNF1 and HNF4 mRNA were also decreased following RA treatment. AFP promoter-chloramphenicol acetyltransferase transient transfection assays demonstrated that the level of HNF1 had a direct impact on basal transcription as well as RA-mediated down-regulation of the AFP gene, and that co-transfection of HNF1 and HNF4, but not transfection of either factor alone, reversed the RA-mediated inhibition. Taken together these data point to an interaction among the RA, HNF1, and HNF4 signals, which is reflected in decreased expression of AFP.

Animals↗

PubMed1998

Identification of a novel truncated alphaIIb integrin.

Integrin alphaIIb beta3 requires its cytoplasmic tails to participate in tumor cell adhesion, spreading, and migration. Using 3' rapid amplification of cDNA ends, we have amplified two alphaIIb cDNAs from human leukemia, prostate adenocarcinoma, and melanoma cells. One of these is the predicted wild-type alphaIIb cDNA, and the other is a novel truncated alphaIIb variant. This variant is unique in that it lacks the transmembrane and cytoplasmic portions of the alphaIIb light chain. The truncated alphaIIb integrin protein is expressed by human leukemia, prostate adenocarcinoma, and melanoma cells but not by platelets or normal prostate epithelial or normal breast epithelial cells. Tumor cells secrete this protein and deposit it on the extracellular matrix. To our knowledge, this is the first report of a naturally occurring variant of an alpha integrin that lacks the transmembrane and cytoplasmic tail.

Alternative Splicing↗

PubMed1998

Role of alphaII(b)beta3 integrin in prostate cancer metastasis.

BACKGROUND: Integrins participate in cell-cell and cell-matrix interactions. In this study we determined whether alphaII(b)beta3 integrin is involved in metastasis of human prostate adenocarcinoma cells. METHODS: Prostate adenocarcinoma PC-3 and DU-145 cell lines express alphaII(b)beta3. Northern blotting, 5'-RACE, and immunofluorescent localization confirmed expression of alphaIIb integrin in prostate adenocarcinoma cells. We used orthotopic/ectopic site of implantation and lung colonization assays in SCID mice to determine whether alphaII(b)beta3 participates in metastatasis of tumor cells. RESULTS: Immunofluorescent localization of alphaIIb integrin in fibronectin-adherent DU-145 and PC-3 cells is remarkably different. In DU-145 cells the integrin localizes to focal contact sites, whereas it is predominantly intracellular in PC-3 cells. Both tumor cell lines are tumorigenic when implanted subcutaneously or intraprostatically in SCID mice, but only DU-145 cells injected intraprostatically metastasize. Flow cytometry with a mAb directed to alphaII(b)beta3 revealed higher expression of alphaII(b)beta3 in DU-145 tumor cell suspensions isolated from the prostate when compared to DU-145 tumor cells from the subcutis. Function-blocking mAbs to alphaII(b)beta3 inhibit lung colonization of tail vein-injected DU-145 cells. CONCLUSIONS: Altogether, the data suggest that alphaII(b)beta3 integrin participates in the metastatic progression of prostatic adenocarcinoma.

Adenocarcinoma↗

PubMed1998

Inhibition of PPAR alpha/RXR alpha-mediated direct hyperplasia pathways during griseofulvin-induced hepatocarcinogenesis.

Chronic griseofulvin (GF) feeding induces preneoplastic foci followed by hepatocellular carcinoma in the mouse liver. Our previous study suggested that GF-induced hepatocellular proliferation had a different mechanism from that of peroxisome proliferator (PP)-induced direct hyperplasia. The GF-induced hepatocellular proliferation was mediated through activation of immediate early genes such as Fos, Jun, Myc, and NFKB. In contrast, PP-induced direct hyperplasia does not involve activation of any of these immediate early genes. It has been shown that nuclear hormone receptors including peroxisome proliferator activated receptors (PPARs) and retinoid x receptors (RXRs) play important roles in mediating the pleiotropic effects of PPs. To examine the possible roles of PPARs and RXRs during non-PP-induced hepatocellular proliferation and the interaction between PP and non-PP-induced proliferation, we have studied the expression of the PPAR and RXR genes in the GF model using northern blot hybridizations and gel retardation assays. The data showed that the expression of PPARalpha and RXRalpha genes was down-regulated in the livers containing preneoplastic nodules and in the liver tumors induced by GF. The mRNA down-regulation was accompanied by a decrease in the amount of nuclear protein-bound to peroxisome proliferator and retinoic acid responsive elements. Down-regulation was also associated with the suppressed expression of the PPARalpha/RXRalpha target genes (i.e., acyl-Co oxidase and cytochrome P450 4A1) and the catalase gene. The RXR-gamma gene was also down-regulated, but the RARalpha, beta, and gamma and PPARbeta and gamma genes were up-regulated. These results indicated that the hepatocarcinogenesis induced by GF is accompanied by suppression of the PPARalpha/RXRalpha-mediated direct hyperplasia pathway. The differential expression of these nuclear hormone receptors reveals a new aspect for understanding the individual roles and intercommunication of PPAR, RXR, and RAR isoforms in the liver.

Acyl-CoA Oxidase↗