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Biomedical subjects

F Ye

Publications and source records attributed to F Ye.

At least 73 records · Page 4Linked to original sources
PubMed1997

[Clinical experience of coronal flap approach in surgery of anterior skull base tumor].

Surgery of the anterior skull base tumor has been undertaken in 7 cases by coronal flap approach, of which 4 cases were malignant tumors and 3 cases were benign tumors. The dura became torn in 3 cases and resected in 2 cases due to tumor invasion. The dura and bony defects could be repaired with galea, pericranial flaps and fascia flaps of temporalis. The bigger bony defect was consolidated with scalp flap. Three out of 4 cases with malignant tumors were free of tumors for 6 years, 4 years and 17 months, respectively: 1 case died of tumor recurrence after 18 months. No case had postoperative complications.

Adolescent↗
PubMed1997

[Symptoms of depressive state in otolaryngology].

A psychiatric study was carried out to seek correct diagnosis and effective therapy for patients with various pain symptoms in ear, nose and throat area, and the unknown cause of pain and invalid treatment. There were 12 patients who coincided with the diagnostic criteria of depression. The therapeutic effect was satisfactory with antidepression medicine. It is suggested that the practicing ENT doctors should have some knowledge of psychiatry, understand the symptoms of depressive state, avoid misdiagnosis and offer correct management.

Adolescent↗
PubMed1997

[Gas chromatographic determination of residual toluene in plastic packing bags].

A method for analysis of residual toluene in plastic packing bags by gas chromatographic headspace analysis is presented. This method is very simple and accurate. It only requires one column: 0.5 m x 2 mm i.d. packed with 102 white support DMCS coated with 20% PEG-20M. The relation between the preheating temperature of sample and the peak height of toluene can be approximately expressed as H=4.156e(0.126T). The precision of this method is 4% and its detectable limit is 0.031 mg (toluene)/m2.

Chromatography, Gas↗
PubMed1997

[Simplex optimization of the automatic gas chromatographic instrument].

A simplex optimization method developed for the automatic gas chromatography is described in this paper. The instrument was developed by ourself based on a gas chromatograph and an auto-sampler, which are controlled by a computer through several assisting circuit boards. A series of chromatographic function SCRF is used in this method for searching the best column temperature for gas chromatographic separation of a given sample. A real sample is used for probation of this method and the results are discussed.

English Abstract↗
PubMed1996

RIGS (repeat-induced gene silencing) in Arabidopsis is transcriptional and alters chromatin configuration.

We have previously reported repeat-induced gene silencing (RIGS) in Arabidopsis, in which transgene expression may be silenced epigenetically when repeated sequences are present. Among an allelic series of lines comprising a primary transformant and various recombinant progeny carrying different numbers of drug resistance gene copies at the same locus, silencing was found to depend strictly on repeated sequences and to correlate with an absence of steady-state mRNA. We now report characterization, in nuclei isolated from the same transgenic lines, of gene expression by nuclear run-on assay and of chromatin structure by nuclease protection assay. We find that silencing is correlated with absence of run-on transcripts, indicating that expression is silenced at the level of transcription. We find further that silencing is also correlated with increased resistance to both DNase I and micrococcal nuclease, indicating that the silenced state reflects a change in chromatin configuration. We propose that silencing results when a locally paired region of homologous repeated nucleotide sequences is flanked by unpaired heterologous DNA, which leads chromatin to adopt a local configuration that is difficult to transcribe, and possibly akin to heterochromatin.

Arabidopsis↗
PubMed1996

The gamma subfamily of DNA polymerases: cloning of a developmentally regulated cDNA encoding Xenopus laevis mitochondrial DNA polymerase gamma.

We used the known sequence of the Saccharomyces cerevisiae DNA polymerase gamma to clone the genes or cDNAs encoding this enzyme in two other yeasts, Pychia pastoris and Schizosaccharomyces pombe, and one higher eukaryote, Xenopus laevis. To confirm the identity of the final X.laevis clone, two antisera raised against peptide sequences were shown to react with DNA polymerase gamma purified from X.laevis oocyte mitochondria. A developmentally regulated 4.6 kb mRNA is recognized on Northern blots of oocyte RNA using the X.laevis cDNA. Comparison of the four DNA polymerase gamma gene sequences revealed several highly conserved sequence blocks, comprising an N-terminal 3'-->5'exonuclease domain and a C-terminal polymerase active center interspersed with gamma-specific gene sequences. The consensus sequences for the DNA polymerase gamma exonuclease and polymerase domains show extensive sequence similarity to DNA polymerase I from Escherichia coli. Sequence conservation is greatest for residues located near the active centers of the exo and pol domains of the E.coli DNA polymerase I structure. The domain separating the exonuclease and polymerase active sites is larger in DNA polymerase gamma than in other members of family A (DNA polymerase I-like) polymerases. The S.cerevisiae DNA polymerase gamma is atypical in that it includes a 240 residue C-terminal extension that is not found in the other members of the DNA polymerase gamma family, or in other family A DNA polymerases.

Amino Acid Sequence↗
PubMed1996

Extensive chromosome aberrations in Spiroplasma citri Strain BR3.

Genetic variations in the plant pathogen, Spiroplasma citri strain BR3, were characterized through physical genome mapping of the original isolate, BR3-3X, and two derivatives, BR3-T and BR3-G, obtained after several years of different maintenance conditions. BR3-T was transmitted from plant to plant via its natural insect vector, the leafhopper Circulifer tenellus, while BR3-G was maintained only in plants by periodic grafting and has lost its ability to be insect transmitted. By pulsed field gel electrophoresis (PFGE) analysis and DNA hybridization, extensive changes in chromosomal DNA restriction patterns relative to the parent, BR3-3X, were observed in both BR3-T and BR3-G, each of which also had a larger genome size than the parent line. Genetic organization was relatively conserved between BR3-T and BR3-3X. In contrast, a large chromosomal inversion and deletions of approximately 10 kb near each of the inversion borders were observed in BR3-G. One of the deletions, which included several possibly functional genes, was closely linked to a SpV1-related transposase gene. The locations of the deletion borders were also determined. The results of this study demonstrated remarkable genome instability of spiroplasmas.

Amino Acid Sequence↗
PubMed1996

[Application of nasal endoscopy and cryosurgery in transsphenoidal removal of pituitary tumors].

In order to sum up the experience of transsphenoidal resection of pituitary tumors, 60 cases operated between 1984 and 1995 were reviewed. The operation was performed via a columella nasi "V" incision and transseptal-sphenoidal approach. 0 degree and 30 degrees endoscopes were used in 16 cases and the cryotherapy was used to destroy the remnant tumor cells in 51 cases. The duration of freezing was only one minute each time and it was repeated once again after thawing. The advantages of this method were as follows: (1) wider operative field and better illumination; (2) magnified operative pictures and TV monitoring; (3) wide and changeable visual angle; (4) lack of complications such as hemorrhage, optic nerve injury, permanent diabetes insipidus. The proper applications of endoscopy and cryosurgery were recommended for transsphenoidal removal of pituitary tumors.

Adenoma↗
PubMed1994

Cloning and sequencing of the replication origin (oriC) of the Spiroplasma citri chromosome and construction of autonomously replicating artificial plasmids.

A 5.6-kbp fragment of Spiroplasma citri DNA containing the dnaA gene has been cloned and sequenced. Nucleotide sequence analysis shows that this fragment harbors the genes for the replication initiator protein (dnaA), the beta subunit of DNA polymerase III (dnaN), and the DNA gyrase subunits A and B (gyrA and gyrB). The arrangement of these genes, dnaA-dnaN-gyrB-gyrA, is similar to that found in all Gram-positive bacterial genomes studied so far, except that no recF gene was found between dnaN and gyrB. Several DnaA-box consensus sequences were found upstream of dnaA and in the dnaA-dnaN intergenic region. The dnaA region with the flanking DnaA-boxes and the tetracycline resistance determinant, tetM, were linked into a circular recombinant DNA. This DNA was able to replicate autonomously when introduced by electroporation into S. citri cells. These experiments show that the dnaA region with the DnaA-boxes is the origin of replication of S. citri and can be used to construct gene vectors.

Amino Acid Sequence↗
PubMed1994

Stimulation of glucagon-like peptide-1 secretion by muscarinic agonist in a murine intestinal endocrine cell line.

Studies on the cholinergic regulation of intestinal L-cells have been focused on the release of enteroglucagon, but the signal transduction pathways were not defined. These were here investigated by using as index the release of immunoreactive glucagon-like peptide-1 (GLP-1) from the endocrine cell line STC-1, that has been shown to contain proglucagon mRNA transcripts. Abundant GLP-1 immunoreactivity was revealed in STC-1 cells at immunocytochemistry and by RIA. The cell content was 4927 +/- 689 pg/10(6) cells, as measured with antiserum 199D that recognizes specifically the C-terminal amidated forms of GLP-1. The secretion of GLP-1 over a 2-h incubation period amounted to 1.4 +/- 0.3% of the total GLP-1 cell content and was significantly increased by 10 microM forskolin and 100 nM 12-O-tetradecanoylphorbol 13-acetate to 206% and 574% of control values, respectively. The cholinergic agonist carbachol stimulated GLP-1 secretion in a concentration-dependent manner, maximal release was observed at 1 mM carbachol (228% of the control value). Binding of the muscarinic antagonist [N-methyl-]scopolamine ([3H]NMS) on cell homogenates was time dependent, specific, and saturable. Scatchard analysis revealed one class of receptors (Kd, 14 pM; binding capacity, 20 fmol/mg protein). Carbachol (0.1 microM to 1 mM) dose dependently displaced [3H] NMS binding and increased the intracellular calcium concentration without modification of adenylate cyclase activity. The order of potency of different antagonists, showing a preferential affinity for M1, M2, and M3 muscarinic receptor subtypes, to inhibit [3H]NMS binding, the carbachol-induced increase in intracellular calcium, and carbachol-stimulated GLP-1 secretion, was as follows: atropine (nonselective) > 4-diphenylacetoxy-N-methylpiperidine methiodide (M3) > pirenzepine (M1) > AF-DX 116 (M2). The results of the present study, therefore, demonstrate that secretion of GLP-1 induced by cholinergic agonist depends on muscarinic M3-subtype receptors in the endocrine intestinal cell line STC-1. This system may prove useful to study the cellular mechanisms of GLP-1 secretion.

Calcium↗
PubMed1994

[Detection of specific DNA fragment of Plasmodium falciparum by solid phase PCR].

Solid phase PCR for detecting Plasmodium falciparum was established and used to detect cultured FCCl/HN isolate and malaria patients in Yunnan Province. The results revealed that the sensitivity of the method for detecting FCCl/HN isolate DNA was as minimal as 0.2 pg, or about 10 parasites. The specificity of the method was confirmed by discriminating malaria patients infected with different species of Plasmodium. The results suggest that solid phase PCR is a specific and sensitive method for early detection of P. falciparum.

Animals↗
PubMed1994

[An animal model for testing hypoglycemic and hypolipidemic drugs].

A new animal model of hyperglycemia and hyperlipidemia was established by treating normal Kunming mice with alloxan (iv). After different time intervals, the levels of blood glucose (BG) and serum triglyceride (TG) were determined. Forty-eight h after alloxan administration, the BG increased significantly, and the level of serum triglyceride reached maximum. The levels of blood glucose, serum triglyceride, cholesterol (CHOL) and free fatty acid (FFA) for vehicle treated mice were about 3.1, 4.0, 1.1, and 1.7 times those of normal Kunming mice, respectively. To evaluate the new animal model, four drugs were used. Two of them were antihyperglycemic drugs, metformin and a Recipe of Chinese Herbs (RCH). The other two were antihyperlipidemic agents, clofibrate and fenofibrate. All drugs showed positive effects on this kind of alloxan-diabetic Kunming mice. It can be concluded that this kind of alloxan-treated Kunming mice is useful for testing hypoglycemic and hypolipidemic drugs.

Animals↗
PubMed1993

Genes for ribosomal proteins S3, L16, L5 and S14 are clustered in the mitochondrial genome of Brassica napus L.

We have cloned and sequenced an 8.9-kb mitochondrial-DNA fragment from rapeseed (Brassica napus L.). The nucleotide sequence indicates a gene cluster that encodes four ribosomal proteins (S3, L16, L5, S14), two tRNA genes (trnD, trnK), and the 5' region of the cob gene. The arrangement of these seven genes is trnD-trnK-rps3-rpl16-rpl5-rps14-cob. The rps3 and rpl16 frames overlap by 131 bp. The rpl5 and rps14 genes are separated by a 4-bp spacer. A 1474-basepair intron is located in the rps3 gene. The tRNA(Asp) gene (trnD) is very similar to the corresponding gene from chloroplasts (cp-like-tRNA(Asp)). Gene-specific probes for each ribosomal protein gene, and for the cp-like-trnD, trnK and cob genes, hybridized to a common pre-mRNA of an estimated size of 10 kilobases, indicating that these seven genes may be expressed as a single transcription unit. The rps3-rpl16-rpl5-rps14 region of B. napus mtDNA may function as a ribosomal operon, similar to the S10 and SPC operons of Escherichia coli and to the ribosomal protein operon of the chloroplast genome from Euglena gracilis.

Amino Acid Sequence↗
PubMed1993

[Study of c-erbB-2 expression in breast neoplasms].

A monoclonal antibody, NCL-CB11, raised against a synthetic peptide from the predicted sequence of the c-erbB-2 protein has been used immunohistochemically in a retrospective study of formalin-fixed paraffin embedded breast neoplasm biopsies. Sixty-five out of 115 infiltrating ductal carcinoma, eleven out of 15 intraductal carcinoma and seventeen out of 22 mammary Paget's diseases exhibited positive membrane staining, indicating amplification of the gene in these tumours. In infiltrating ductal carcinoma, there was a positive correlation between c-erbB-2 overexpression and axillary lymph node metastasis as well as between the overexpression and the number of mitotic figures. These results suggest that c-erbB-2 expression might be used as a predictive marker for the worse prognosis of breast carcinoma. The significance of c-erbB-2 expression in other malignant tumours and benign lesions is also discussed.

Biomarkers, Tumor↗
PubMed1992

A physical and genetic map of the Spiroplasma citri genome.

A physical and genetic map of the Spiroplasma citri genome has been constructed using several restriction enzymes and pulsed field gel electrophoresis. A number of genes were subsequently localized on the map by the use of appropriate probes. The genome size of the spiroplasma estimated from restriction fragments is close to 1780 kbp, the largest of all Mollicutes studied so far. It contains multisite insertions of Spiroplasma virus 1 (SpV1) sequences. The physical and genetic map of the S. citri genome shares several features with that of other Mollicutes, especially those in the Mycoplasma mycoides cluster. This supports the finding that S. citri and these Mycoplasma spp. are phylogenetically related.

Bacteriophages↗
PubMed1992

Structure and expression of the phosphoglycerate kinase (Pgk) gene of Drosophila melanogaster.

The gene that encodes phosphoglycerate kinase in Drosophila melanogaster (Pgk) has been isolated and characterized. There is a single copy of Pgk in the Drosophila genome located at cytogenetic position 23A1-2. Transcripts of Pgk are 1.6 kb long and are found during development with a profile similar to the expression pattern of other genes of the glycolytic pathway. There are substantial amounts of maternal transcript in early embryos which decline in abundance until mid-embryogenesis when transcript levels increase; levels remain high, during larval stages, fall during pupariation and rise again at emergence. The nucleotide sequence of the Pgk gene reveals two small introns, one of which is at a position identical to the site of an intron found in Pgk genes from other organisms. The Pgk gene has no TATA box in the region of transcription initiation and has multiple transcription initiation sites that are closely spaced within 110 nucleotides of the translation start site.

Amino Acid Sequence↗