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Biomedical subjects

M X Ding

Publications and source records attributed to M X Ding.

29 records · Page 2Linked to original sources
PubMed1983

Electron microscopic autoradiographic studies on effects of duck plague virus (DPV) multiplication on nucleoli and their RNA transcription.

The nucleolar structures could be observed in primary chicken embryo cells at 12, 24, 36, 40 and 60 hr after infection with DPV. By means of electron microscopic autoradiography and Bernhard staining method, it could not only demonstrate the existence of nucleoli in infected cells morphologically and functionally, but also further indicate that the incorporation of 3H-Uridine still progressed very rapidly while the viral DNA was intensely replicating, the majority of nucleocapsids were assembled and the maturation of viruses began to appear in the infected cells. In the cells at 24 hr after infection with DPV, the average number of silver grains per unit area on the nucleolar surface was still 82.7% corresponding to that seen in controls. All these phenomena suggest that in DPV-infected cells, the nucleolar structure still exists and its function of RNA transcription keeps going on. These phenomena are different from the previous reports on other species of herpesviruses, and will be discussed in this paper.

Animals↗
PubMed1982

Electron microscopic autoradiographic studies on dynamics and location of DNA synthesis of duck plague virus.

Electron microscopic autoradiographic studies on the dynamics and location of DNA synthesis by means of incorporation of 8H-thymidine during the replication of duck plague virus (DPV) revealed that the duration of DNA synthesis of DPV was rather long. The replication of viral DNA occurred simultaneously with the assembly procedure of nucleocapsids, the maturation and release of viruses. DNA synthesis of DPV occurred in the matrix with lower electron density in the nucleus. The replicated viral DNA accumulated in the viroplast with high electron density where the assembly of nucleocapsids occurred. The viroplast with high electron density was not the region of viral DNA synthesis.

Animals↗
PubMedDate not supplied

Expression of bcl-2 and Bax in EGFR-antisense transfected and untransfected glioblastoma cells.

Glioblastomas are the most frequent and most malignant astrocytic gliomas. The epidermal growth factor receptor (EGFR) gene is the most frequently amplified and overexpressed in glioblastomas. The expression of bcl-2 and Bax in EGFR-antisense transfected and un-transfected glioblastoma cell line, U87E and U87V was studied by immunohistochemistry and western blotting. Our results show that the expression of Bax was stronger and bcl-2 was weaker in EGFR-antisense transfected cell line than the untransfected control. Bcl-2 and Bax genes are probably involved in the reduction of malignancy of glioblastoma cell caused by the introduction of EGFR-antisense into these tumor cells.

Apoptosis↗
PubMedDate not supplied

Association of EGFR gene fragments with nuclear matrix proteins in high and low metastatic melanoma cell lines.

Two melanoma cell lines with different metastatic potential were used to study the association of EGFR gene fragments with the nuclear matrix and its role in cancer metastasis by polymerase chain reaction. A 940 bp positive amplification by PCR using primers I-II was demonstrated in a high metastatic cell line, WM451. A 110 bp positive amplification was shown using primers III-IV in both high and low metastatic cell lines. This finding demonstrates that EGFR gene fragments are tightly bound to the nuclear matrix and suggests that binding ability of this EGFR gene fragment to nuclear matrix seems to be closely related to metastatic potential in melanoma cell lines WM45 1 and WM35.

Antigens, Nuclear↗
PubMedDate not supplied

Bcl-2 and Bax proteins are nuclear matrix associated proteins.

Bcl-2 and Bax proteins are implicated in the regulation of apoptosis. Nuclear matrix has been demonstrated to be associated with a vast array of functional and regulatory properties of cells. NuMA is one member of a class of nuclear matrix proteins that resides in both the nucleus and mitotic apparatus. The nuclear lamins appear to form a thin fibrous structure immediately underlying the inner nuclear membrane of eukaryotic cell nuclei. The association of bcl-2 and Bax protein with nuclear matrix in glioblastoma cell line U343 was studied by confocal microscopy and Western blotting. Confocal microscopic images display that bcl-2 was localized at the peripheral of the nuclear matrix and Bax protein was located in the nuclear matrix. Western blotting detected a 26 kDa bcl-2 band and a specific band of Bax at around 66 kDa in nuclear matrix proteins. Our results suggest that bcl-2 and Bax proteins are nuclear matrix associated proteins.

Antigens, Nuclear↗
PubMedDate not supplied

Fine structural observations on the human sperm nuclear matrix.

The nucleus of the mammalian sperm is formed after a series of morphological and biochemical changes during spermatogenesis. The human sperm nucleus, after sequential extraction with detergents, nuclease and ammonium sulfate, consists of a fibroskeletal structure which maintains the original nuclear shape. The chromatin-depleted skeleton is formed by thick and thin fibers as well as electron-dense patches of different sizes. These highly branched matrix fibers had average diameters of 35 and 12 nm. Polarization of the fibroskeletal structure is apparent and can be used as a good model to study the function of nuclear matrix in nuclear compartmentation in germ cells.

Chromatin↗
PubMedDate not supplied

Association of EGFR gene fragments with nuclear matrices in glioblastoma cell lines.

The association of epidermal growth factor receptor DNA fragments with nuclear matrix in glioblastoma cell lines was investigated. Two different DNA fragments (primer I-III, 940 bp and primer IV-V, 110 bp) were amplified in both genomic DNA and nuclear matrix-associated DNA. It was found that the 110 bp DNA fragment (primer IV-V) from a non-encoding region was more closely associated with the nuclear matrices of cell line U343, U373, A172, and T98 than with U87. The other DNA fragment (primer I-III) was found in both the genomic DNA and NM DNA from cell line of U343 and U87. Another long DNA fragment (primer I-II, 1015 bp) was not detected in the DNA of all cell lines. Our findings suggest that the attachment of the 110 bp DNA fragments to nuclear matrix may contribute to the growth and malignancy of glioblastoma.

DNA Fragmentation↗