Biomedical subjects

Qing Cheng

Publications and source records attributed to Qing Cheng.

25 records · Page 2Linked to original sources

PubMed2003

[The expression of proliferating cell nuclear antigen and Bcl-2 oncoprotein in nasopharyngeal carcinoma].

OBJECTIVE: To observe PCNA, Bcl-2 gene expression and their relationship with clinicopathologic factors in primary nasopharyngeal carcinoma(NPC). METHOD: PCNA, Bcl-2 proteins were assayed with immunohistochemical technique. RESULT: The expression of Bcl-2 protein was 9.5% in chronic inflammation of nasopharyngeal epithelium(CINE), which was significantly lower than it in NPCs with 83.1% (P < 0.01). In NPCs, we could find PCNA and Bcl-2 expression were significantly negatively correlated with each other(rs = -0.41, P < 0.01). In our study, there was some correlation in the grade of PCNA proliferating index(PI) with the clinical stages or cervical lymph node metastasis of NPCs. CONCLUSION: PCNA PI may represent the proliferative state of NPC, Bcl-2 protein may be a better tumor marker of NPC, all of them may play important roles in the pathogenesis of nasopharyngeal carcinoma.

Adolescent↗

PubMed2003

[The dosage of SDS when extracting membranous labyrinth proteins].

OBJECTIVE: To determine the appropriate dosage of SDS when extracting membranous labyrinth proteins. METHOD: The yield of proteins extracted with various amounts of SDS were determined by BCA method, and the components of the extracted proteins were analyzed by SDS-PAGE. RESULT: The amount of proteins extracted with 0.1% SDS is less than that with 0.23%, 1% or 2% SDS, meanwhile it shows less bands than the other and the corresponding bands are stained weaker. 0.23% SDS is less efficiently than 1% and 2% SDS in solubilizing proteins. There is no significant difference between 2% and 1% SDS in yield of proteins, while 2% SDS accompanies a higher ratio of detergent to protein. CONCLUSION: 1% SDS is solutions is relatively suitable for extracting membranous labyrinth proteins extensively while the ratio of detergent to protein is from 5 to 6.

Animals↗

PubMed2002

Alternative splicing of the GABA(A) receptor alpha 4 subunit creates a severely truncated mRNA.

GABA(A) receptors, important sites of drug action, are chloride channels composed of 5 subunits chosen from among 19 or more. Alternative splicing for alpha 5, alpha 6, and rho 1 subunits results in truncated proteins which appear to lack function. We report a similar, relatively common (about 20%) form of alternative splicing of the alpha 4 subunit mRNA in mice and humans which, remarkably, creates a severely truncated message containing only the first two and last coding exons, with a frameshift in between. The only apparent translation product includes a short piece (39 amino acids) of the N-terminus right after the signal peptide. The splicing was developmentally and regionally regulated; the highest proportions of truncated alpha 4 mRNA, about 40%, were observed in embryonic day 18 whole brain and adult cerebellum. The truncated mRNA, when coexpresssed in human embryonic kidney (HEK) 293 cells with the complete alpha 4 subunit and beta1 and gamma 2 S subunits, reduced observed GABA currents without kinetic alterations. No such effect of truncated alpha 4 was observed with alpha1 subunit-containing receptors. Thus, the truncated alpha 4 N-terminus may play a post-translational regulatory role in intracellular folding/glycosylation/assembly of the alpha 4 subunit.

Alternative Splicing↗

PubMed2002

Photolysis of gamma-(alpha-carboxy-2-nitrobenzyl)-L-glutamic acid investigated in the mcrosecond time scale by time-resolved FTIR.

The photolytic release of substrates from caged substrates has proven to be an excellent method to generate concentration jumps for kinetic measurements in the microsecond time scale. In this report we use time-resolved FTIR in the step-scan mode to probe the photolysis mechanism of one such caged compound, namely gamma-(alpha-carboxy-2-nitrobenzyl)glutamate, and to obtain a direct measure of the rate of photorelease of the substrate glutamate. The time-resolved difference FTIR spectra exhibit specific signals that can be assigned to the reactant caged glutamate, photolytically released product glutamate, as well as to the aci-nitro intermediate, the key intermediate of the photolysis reaction. Therefore these signals allow the characterization of the kinetics of formation and decay of the intermediate and products. This is the first such report that provides a direct determination of the rate of formation of the photolysis product from a caged compound in the microsecond time scale. Furthermore, the results presented provide a good basis for further time-resolved FTIR studies of molecular reaction mechanisms, such as ligand protein interactions, in the microsecond time scale through the photolytic release of substrates from caged compounds.

Glutamates↗

PubMed2002

Identification and characterization of genes involved in the carcinogenesis of human squamous cell cervical carcinoma.

We utilized RT-PCR differential display and cDNA microarrays to identify cellular genes involved in the multi-step carcinogenesis of squamous cell cervical carcinoma. Thirty-eight cervical cancer patients in various stages of the disease and 5 non-cervical cancer patients were studied. Twenty-five cDNA clones were identified and these were subsequently demonstrated to be consistently over-expressed in squamous cell cervical carcinoma biopsies of various FIGO stages. To further evaluate the possible role that these genes may play in the progression of disease, we performed Northern blot analysis and RNA-RNA in situ hybridization studies using cervical cancer biopsies of various FIGO stages. Of particular interest are the 2 clones G32C4B and G30CC that have been identified to be the NADH dehydrogenase 4 gene and the gene that encodes ribosomal protein S12 respectively when compared to sequences available in the GenBank database. Increased expression of these 2 genes were detected in the matched normal tissues collected together with the late FIGO stages of cervical cancer biopsies. In comparison, upregulation of these 2 genes was not detected in cervical squamous epithelium collected from patients admitted for surgery for non-malignant conditions, suggesting that expression of these 2 genes may have altered in the adjacent histopathologically "normal" cervical squamous epithelial tissue from cervical cancer patients. The ribosomal protein S12 and the NADH dehydrogenase 4 genes may therefore be potentially useful as early pre-transformation diagnostic markers for human cervical cancer.

Biomarkers, Tumor↗

PubMed2002

A vibrational spectroscopic investigation of interactions of agonists with GluR0, a prokaryotic glutamate receptor.

We have used Fourier transform infrared spectroscopy to provide a detailed picture of the interactions between the carboxylate groups of the ligands, glutamate, serine, and glutamine, with the ligand-binding domain of a prokaryotic ionotropic glutamate receptor (GluR0). The vibrational spectra indicate that the noncovalent interactions between the 1C(alpha)-carboxylate moiety of the ligand and the protein are stronger for glutamate than for serine and glutamine. These results correlate well with the higher affinity of glutamate for GluR0-S1S2 relative to the affinities of serine and glutamine. In addition, all three ligands induce similar changes in the vibrational spectra and intrinsic fluorescence of the protein, which indicates that all three ligands induce the same structural changes in the protein. These results are consistent with the recent crystal structures of the glutamate and serine bound forms of GluR0-S1S2 and in addition provide insights into the structure of the glutamine bound form of the protein.

Bacterial Proteins↗

PubMed2002

[Sudden deafness with large vestibular aqueduct (case report and literatures review)].

OBJECTIVE: To study the clinical feature of large vestibular aqueduct syndrome and diagnostic basis of large vestibular aqueduct on high resolution computer tomography. METHOD: Report a 18 year old man who presented a sudden deafness in right ear and his left ear arised the same disorder before 11 months. Since childhood his both ears have occurred sensorineural hearing loss, which causations were reserved unknown. The temporal bone axially oriented high resolution computer tomography scanning showed a enlarged vestibular aqueduct without associated cochlear anomalies of both ears. In addition the literatures about this disorder are reviewed. RESULT: The large vestibular aqueduct syndrome without association cochlear anomalies may occurs acquired sensorineural hearing loss and appears to be at high risk for sudden deafness. CONCLUSION: It is important to identify followed by high-resolution computer tomography whether a large vestibular aqueduct syndrome when a causal uncertain sensorineural hearing loss or/and a sudden deafness onset in childhood is represented.

Adolescent↗