[Primary carcinoma of the gallbladder].
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Adult↗
Biomedical subjects
M Gao
Publications and source records attributed to M Gao.
Detection of eIF4E gene amplification in breast cancer by competitive PCR.
BACKGROUND: Initiation factor eIF4E binds to mRNA as the initial step for protein translation. Overexpression of the eIF4E oncoprotein has been found in breast cancer but not in benign breast tissue. The objective of this study is to determine if eIF4E oncoprotein overexpression is associated with eIF4E gene amplification in breast cancer using Western blots and competitive polymerase chain reaction (PCR). METHODS: Unknown concentrations of DNA extracted from breast specimens were amplified by PCR using a set of primers spanning intron 2/exon 3 of the eIF4E gene. In the same PCR tube, an internal control consisting of a known concentration of an eIF4E DNA template with 20-base pair (bp) deletion was used as the competitive reference standard (CRS) for competitive PCR. Gel electrophoresis of the PCR products was performed and the bands quantified by densitometry. eIF4E gene amplification was then determined relative to a nonamplified gene (gastrin). Using an anti-eIF4E rabbit antibody, Western blots were performed on benign and malignant breast specimens. Quantification was accomplished by developing blots with a color assay using nitro blue tetrazolium (NBT) and 5-bromo-4-chloro-3-indolyl phosphate (BCIP), scanned and analyzed by densitometry. RESULTS: Twenty-two breast specimens (14 cancer, 8 control) from patients were examined for eIF4E gene amplification and oncoprotein expression. In all fourteen specimens from stage I-III breast cancer patients, eIF4E overexpression was detected at 3- to 30-fold ( 16.71 +/- 7.83) elevations. Similarly, all 14 specimens demonstrated eIF4E gene amplification by competitive PCR (3.69 +/- 1.27). In the eight benign breast specimens examined, all were negative for eIF4E overexpression and gene amplification. CONCLUSIONS: Overexpression of eIF4E was associated with eIF4E gene amplification in breast cancer specimens. No overexpression or gene amplification was detected in benign breast tissues. eIF4E gene amplification may be one mechanism for eIF4E oncoprotein overexpression.
Animals↗
A novel approach to high-throughput quality control of parallel synthesis libraries.
Combinatorial chemistry is a powerful tool to enhance drug discovery efforts in the pharmaceutical industry. One type of combinatorial chemistry, parallel synthesis, is now widely used to prepare numerous compounds of structural diversity. A novel high-throughput method for quality control of parallel synthesis libraries has been developed. The method uses flow injection MS, for proof of structure and estimation of purity, and a novel direct injection CLND technique for quantitation of amount. Following the synthesis of a small molecule library, compounds analyzed using this technique were characterized by mass spectrometry, and an accurate concentration of the compound was assessed by CLND. Characterization of one compound is completed in 60 s, allowing for up to 1000 compounds to be analyzed in a single day. The data is summarized using pass/fail criteria using internally developed software.
Chemistry, Organic↗
Identification of a new inducible nodulation gene in Azorhizobium caulinodans.
The narrow host range bacterial strain Azorhizobium caulinodans ORS571 induces the formation of nitrogen-fixing nodules on the root and stem of the tropical legume Sesbania rostrata. Here, a new flavonoid-inducible locus of ORS571 is described, locus 4. The locus was identified and isolated via the occurrence of particular sequences, the gamma and delta elements. These elements are reiterated in the ORS571 genome, linked to symbiotic loci. Sequencing of locus 4 showed the presence of an open reading frame (ORF6) that is flanked downstream by a gamma element and upstream by a delta element. The gamma element is approximately 180 bp in size, and shows homology to the insertion element ISRm3, an insertion sequence belonging to a distinct class of IS elements. The delta element is about 300 bp in size and has homology with repeated sequences found in other Rhizobiaceae. The ORF6 gene product shows a low, but significant homology to the mouse mastocytoma antigen P35B (Szikora et al., EMBO J. 9: 1041-1050, 1990) and to a class of NAD/NADP-binding sugar epimerase/dehydrogenases (Pissowotzki et al., Mol. Gen. Genet. 231: 113-213, 1991). Immediately upstream from ORF6, a nod box-related sequence is present, the arrangement of which is fully consistent with a recently presented model for the nod box structure (Goethals et al., Proc. Natl. Acad. Sci. USA 89: 1646-1650, 1992). Insertional inactivation of ORF6 did not affect the nodulation and fixation performance on S. rostrata. However, on S. formosa roots the nodulation kinetics of such a mutant was clearly affected (about 5 days delay). We propose to call this new symbiotic gene nolK.
Amino Acid Sequence↗
Expression of estrogen receptor-related receptor isoforms and clinical significance in endometrial adenocarcinoma.
Estrogen receptor-related receptors (ERRs) are members of orphan nuclear receptors closely related to the estrogen receptors (ERs). Researches showed that the ERRs bound to estrogen response elements and interfered in the ER signal pathway. Therefore, it might be associated with estrogen-dependent diseases. The purpose of this study was to explore whether ERRs were involved in the tumorigenesis of endometrial adenocarcinoma. We examined the expression of ERRs in endometrial adenocarcinoma and normal endometrium using semiquantitative reverse transcription-polymerase chain reaction and immunohistochemistry. Clinicopathologic features including FIGO stage, histologic grade, myometrial invasion, and nodal metastasis were reviewed. Results showed that messenger RNA (mRNA) levels of ERRalpha, ERRbeta, and ERRgamma were positively associated with the immunoreactivities (P= 0.009, P= 0.014, and P= 0.001, respectively). The expression rate and relative level of ERRalpha mRNA in ERalpha-positive endometrial adenocarcinomas were lower than in normal endometriums (P= 0.049 and P= 0.023), whereas the relative level of ERRgamma mRNA in ERalpha-positive endometrial adenocarcinomas was higher than in normal endometriums (P= 0.014). Expression of ERRalpha mRNA was positively correlated with FIGO stage (P= 0.019) and myometrial invasion (P= 0.043). A negative correlation was observed between expression of ERRgamma mRNA and nodal metastasis (P= 0.021). Results suggested that ERRalpha and ERRgamma might participate in the tumorigenesis of endometrial adenocarcinoma. ERRalpha and ERRgamma are promising to be new prognostic factors in endometrial adenocarcinoma.
Adenocarcinoma↗
Expression of c-fos protein in serotonergic neurons of rat brainstem following electro-acupuncture.
The c-fos proto-oncogene encodes a nuclear phosphoprotein, Fos which has been proposed to be a "third messenger" coupling short term extracellular signals to long term alteration in cell function. Using double labeling immunocytochemistry, the present work demonstrated the co-localization of Fos protein and serotonin in the nucleus raphe dorsalis, nucleus raphe centralis superior and rostral ventromedial medulla. The results pose an interesting problem, the possible relation of Fos protein to the biosynthesis of serotonin, awaiting further investigation.
Animals↗
Involvement of mu opioid receptors of periaqueductal gary (PAG) in acupuncture inhibition of noxious blood pressure response in rabbits.
Strong electric shock stimulation of the rabbit front paw elicited a pressor blood pressure response regarded as noxious response. Ligands of mu opioid receptors were microinjected into the PAG to observe their effects on acupunture inhibition of the pressor response. (1) Ohmefentanyl (OMF), a mu agonist, significantly attenuated the pressor response. Mu antagonist TCTAP greatly enhanced the pressor response. (2) Electroacupuncture (EA) significantly inhibited the pressor response, the inhibition being readily reversed by TCTAP. The response after TCTAP was significantly greater than that of the control before EA. The results suggest that noxious stimulation is able to activate the mu opioid receptor of the PAG to modulate the noxious response and EA is able to enhance the activation.
Animals↗