Biomedical subjects

Jian Fei

Publications and source records attributed to Jian Fei.

44 records · Page 3Linked to original sources

PubMed2003

Involvement of dopamine D3 and neuropeptide Y Y5 receptors in diabetic gastroparetic rats without response to erythromycin.

Erythromycin may accelerate gastric emptying in animals and human probably as an motilin agonist, but its prokinetic effects show obvious individual disparity. This study was to find the mechanism of this phenomenon. Microarray analysis was used to screen genes that might be involved in the response of diabetic gastroparesis rats to erythromycin. It was found that erythromycin accelerated gastric emptying of diabetic rats with great individual disparity. Through microarray analysis we screened differential expression genes that might be involved in the effect of erythromycin. Among 10 genes screened out, dopamine D3 receptor (DRD3) and neuropeptide Y Y5 receptor (NPYY5) genes were submitted to RT-PCR quantification and showed consistent results with microarray. It can be concluded that erythromycin promote gastric emptying of gastroparetic rats; DRD3 and NPYY5 may be involved in prokinetic action of erythromycin; and targets other than motilin receptor of erythromycin might exist as prokinetics.

Animals↗

PubMed2003

Increase in drug-induced seizure susceptibility of transgenic mice overexpressing GABA transporter-1.

AIM: The changes of seizure susceptibility of transgenic mice overexpressing GABA transporter-1 (GAT-1) were studied to clarify the possible role of GABAergic transmission in epileptogenesis. METHODS: Seizures were induced by intraperitoneal administration of pentylenetetrazol (PTZ), picrotoxin (PIC), or kainic acid (KA) respectively. The anticonvulsant effect of ethyl nipecotate was tested by its intraperitoneal injection 15 min before the administration of the epileptogenic agents. RESULTS: The percentages of occurrence of clonic seizures induced by PTZ 45 mg/kg, PIC 2.5 mg/kg, or KA 20 mg/kg in GAT-1 transgenic mice were 88.9 %, 100 %, and 83.3 % respectively, whereas those in control C57BL/6J mice were 42.9 %, 57.1 %, and 33.3 %. The percentages of occurrence of tonic seizures induced by PTZ 45 mg/kg, PIC 2.5 mg/kg, or KA 20 mg/kg in transgenic mice were 88.9 %, 100 %, and 83.3 % respectively, and whereas those in control mice were 28.6 %, 42.9 %, and 16.7 %. The latencies of both clonic and tonic seizures onset in transgenic mice were markedly shortened compared with those in control animals. The results indicated that GAT-1 transgenic mice showed increased susceptibility to seizures induced by the anti-GABAergic convulsive drugs (PTZ, PIC), as well as glutamic receptor agonist (KA). Ethyl nipecotate, inhibitor of GAT-1, inhibited PTZ-induced seizures in both GAT-1 transgenic and C57BL/6J mice. The incidence of seizures was decreased after the application of ethyl nipecotate, and the latencies to the onset of clonic or tonic seizures were also prolonged. CONCLUSION: The increase in seizure susceptibility of transgenic mice over-expressing GAT-1 is an evidence for involvement of GABAergic transmission in epileptogenesis, and this transgenic mouse might be a useful animal model for study on the role of GABAergic transmission in epileptogenesis.

Animals↗

PubMed2003

[Development of salivary gland tumors in pleomorphic adenoma gene 1 transgenic mice].

OBJECTIVE: Activation and overexpression of pleomorphic adenoma (PLAG1) gene due to t(3;8)(p21;q12) translocation are associated with the development of human pleomorphic adenomas of the salivary glands. This study was conducted to generate ubiquitously-expressed or tissue-specific expressed PLAG1 transgenic mice and to elucidate the role of PLAG1 gene in tumorigenesis in vivo. METHODS: Human PLAG1 cDNA was cloned from salivary gland tumor or placenta tissues by RT-PCR. Ubiquitous expression vector pCMV-EGFP/PLAG1 driven by CMV promoter and tissue-specific expression vector pMMTV-PLAG1 driven by MMTV LTR were constructed. NIH3T3 cells transiently transfected with pCMV-EGFP/PLAG1 showed high expression of PLAG1 in nucleus. Transgenes were microinjected into pronucleus of zygotes to generate transgenic mice. RESULTS: It was found that the human PLAG1 cDNA cloned from several salivary gland tumor and normal placenta tissues consistently showed a variation of a single nucleotide at the same position when compared with the human PLAG1 cDNA sequence in Genbank (Accession No. U65002), which led to T458P at protein level. It might be a single nucleotide polymorphism (SNP)locus. Fused EGFP/PLAG1 protein was found to be localized in the nucleus of NIH3T3 cells transiently transfected with pCMV-EGFP/ PLAG1. Several pCMV-EGFP/PLAG1 and pMMTV-PLAG1 transgenic mouse lines were obtained respectively. As might be expected, pMMTV-PLAG1 transgenic mice spontaneously developed salivary gland tumors in three independent lines, among which, line 42 showed tumorigenic phenotype in 100% of transgenic mice within three months after birth. CONCLUSION: Overexpression of PLAG1 gene plays a crucial role in tumorigenesis of salivary gland tumors.

Animals↗

PubMed2002

A mRNA molecule encoding truncated excitatory amino acid carrier 1 (EAAC1) protein (EAAC2) is transcribed from an independent promoter but not an alternative splicing event.

Glutamate transporter EAAC1 removes excitatory neurotransmitter in central nervous system, and also absorbs glutamate in epithelia of intestine, kidney, liver and heart for normal cell growth. When a mouse cDNA was screened using EAAC1 cDNA fragment as probe in our lab, a transcript (GenBank U75214) encoding an EAAC1 protein with 148 residues truncated at N-terminal was cloned and named as EAAC2. Sequence analysis shows that EAAC2 has it's own start code and unique 5'UTR that is different from that of EAAC1. A mouse genomic library was screened and a positive clone including EAAC1 CDS was sequenced (GenBank AF 322393) and indicates that normal EAAC1 transcript (GenBank U73521) is transcribed from 10 exons in terms of exon I, II, III, IV, V, VI, VII, VIII, IX, X, and EAAC2 transcript is consisted by exons from IV to IX as same as that of EAAC1 and with its unique exon beta upstream to exon IV and exon delta downstream to IX. EAAC2 transcript has a cluster of transcriptional start sites not overlapping with the transcriptional start sites of EAAC1. These results indicate that EAAC2 is transcribed from an independent promoter but not an alternative splicing event.

5' Untranslated Regions↗

PubMed2002

Cloning of full length cDNA sequence of the mouse ameloblastin.

OBJECTIVE: Screening for special genes of matrix proteins of dentin and enamel of mouse dental germ. METHODS: A cDNA library of dental germ of mouse was screened by differential display. The interesting clones were sequenced. RESULTS: Six positive clones were isolated from the cDNA library. The sequence of one of the six positive clones was homologous with the ameloblastin sequence of rat. There are 497 homologous base pairs between the 526 base pairs sequenced by pTriplEX 3' primer of this clone and the 32-580 sequence of the rat ameloblastin gene; and there are 533 homologous base pairs between the 567 base pairs sequenced by pTriplEX 5' primer of this clone and the 1285-1854 sequence of the rat ameloblastin gene. CONCLUSIONS: The full length cDNA sequence of the mouse ameloblastin was cloned.

Amino Acid Sequence↗

PubMed2002

[Long-term culture and differentiation of neural stem cells of embryonic mice].

OBJECTIVES: To assess the culture and differentiation of neural stem cells in embryonic mice and set up a basis for further research in to neural stem cells. METHODS: Embryonic cortices of mice were dissociated and single cell suspensions were achieved by mechanical methods in sterile conditions, and cells were seeded in uncoated plate in N2 medium. The cells were passaged by mechanical methods, frozen and thawed by general procedure. They were identified by immunocytochemical techniques. RESULTS: Neural stem cells from embryonic mice were successfully cultured forming typical neurospheres in suspension. Neurons, astrocytes and oligodendrocytes were differentiated from neural stem cells, with a ratio of 7%, 85% - 90% and 2% - 4% respectively. CONCLUSIONS: Neural stem cells, which can be cultured and passaged steadily in vitro and they are the ideal cell sources for cell transplantation and gene therapy.

Animals↗

PubMed2002

[Construction of an angiostatin eukaryotic expression vector and characterization of its inhibitory efficiency in B16 melanoma bearing mice].

Recent studies have demonstrated that angiostatin, a newly discovered specific inhibitor of endothelial cells, may significantly suppress the growth of a variety of tumors. We constructed an eukaryotic expression vector containing angiostatin (pAG3 ). To study the effect of pAG3, we intramuscularly injected pAG3 into B16 melanoma bearing C57 mice, we found that pAG3 could obviously inhibit tumor growth and reduce the size of tumors in B16 melanoma bearing C57 mice compared to the untreated control mice. In addition, we also investigated whether pre-treatment of pAG3 can prevent the tumor formation in mice treated with B16 melanoma. Normal C57 mice which received 5 days of treatment of pAG3 prior to implanting tumors resulted in the inhibitory effect when compared to control mice. No promotive effect was observed when pAG3 was combined with DTIC (Dacarbazine). These findings provide a basis for the further development of nonviral delivery of angiogenic gene therapy.

Angiostatins↗

PubMedDate not supplied

Identification of glutamate receptors and transporters in mouse and human sperm.

gamma-Aminobutyric acid (GABA) and glutamate (Glu) are considered as the predominant inhibitory and excitatory neurotransmitters in mammalian central nervous systems (CNS), respectively. The presence of the GABA system and metabotropic glutamate receptors in sperm prompted us to explore the existence of ionotropic glutamate receptors and glutamate transporters in sperm. Immunofluorescent analysis was used to investigate the existence and location of glutamate, glutamate receptor (NR2B), and glutamate transporter (GLT1) in mouse and human sperm. Our present results showed that NR2B was located in the midpiece of sperm, whereas GLT1 mainly existed in the head. Moreover, glutamate uptake activity was detected in mouse sperm and it could be blocked by dihydrokainic acid (DHK, GLT1-selective inhibitor) and DL-threo-beta-hydroxyaspartic acid (THA, nonselective inhibitor). In addition, reverse transcription-polymerase chain reaction technique and sequencing analysis revealed that glutamate transporters (GLT1 and EAAC1) and ionotropic glutamate receptors (NR1, NR2B, GluR6, and KA2) existed in mouse sperm as well as in human sperm. The present findings are the first direct evidence for the existence of ionotropic glutamate receptors and glutamate transporters in sperm. It also indicates that, in sperm, glutamate receptors and transporters might have functions other than neurotransmission.

Amino Acid Transport System X-AG↗