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Biomedical subjects

E C Chew

Publications and source records attributed to E C Chew.

At least 19 recordsLinked to original sources
PubMed2003

Nuclear matrix associated protein PML: an arsenic trioxide apoptosis therapeutic target protein in HepG2 cells.

OBJECTIVE: To investigate arsenic trioxide (As(2)O(3))-induced apoptosis and the effects on cell nuclear matrix related protein promyelocytic leukaemia (PML). METHODS: HepG2 cells were cultured in MEM medium and treated with 0.5, 2, 5 and 10 micro mol/L As(2)O(3) for either 24 h or 96 h at each concentration. In situ terminal deoxynucleotidyl transferase (TdT) labeling (TUNEL) and DNA ladders were used to detect apoptosis. Confocal microscopy and Western blotting were used to observe the expression of PML. RESULTS: The growth rates of HepG2 cells were slower in the As(2)O(3) treated than the untreated control group. DNA ladder and TUNEL positive apoptotic cells could be detected in As(2)O(3) treated groups. The expression of PML decreased in HepG2 cells with 2 micro mol/L As(2)O(3) treatment. Confocal images demonstrated that the expression of PML protein in HepG2 cell nuclei decreased after treatment with 2 micro mol/L As(2)O(3), and micropunctates characteristic of PML protein in HepG2 cell nuclei disappeared after treatment with 5 micro mol/L As(2)O(3). CONCLUSIONS: Our results show that arsenic trioxide can significantly inhibit the growth of HepG2 cells in vitro. As(2)O(3) induces apoptosis in HepG2 tumor cells in a time and concentration dependent manner. As(2)O(3) may degrade the PML protein in HepG2 cell nuclei. The decreased expression of PML in As(2)O(3) treated tumor cells is most likely to be caused by apoptosis. Nuclear matrix associated protein PML could be the target of As(2)O(3) therapy.

Antineoplastic Agents↗
PubMed2001

Human papillomavirus 16 E6 is associated with the nuclear matrix of esophageal carcinoma cells.

AIM: To explore the etiologic role of HPV infection in esophageal carcinoma, and the association of HPV-16 E6 with the nuclear matrix of carcinoma cells. METHODS: Two esophageal carcinoma cell lines,EC/CUHK1 and EC/CUHK2, were tested for HPV-16 E6 subgenetic fragment by polymerase chain reaction amplification of virus DNA associated nuclear matrix. RT-PCR and immunocytochemistry were also used to visualize the expression of E6 subgene in the cells. RESULTS: The HPV-16 E6 subgenetic fragment was found to be present in nuclear matrix-associated DNA, E6 oncoprotein localized in the nucleus where it is tightly associated with nuclear matrix after sequential extraction in EC/CUHK2 cells. It was not detected, however, in EC/CUHK1 cells. CONCLUSION: The interaction between HPV-16 E6 and nuclear matrix may contribute to the virus induced carcinogenesis in esophageal carcinoma.

Antigens, Nuclear↗
PubMed1999

Prospective cohort study of antioxidant vitamin supplement use and the risk of age-related maculopathy.

In a prospective cohort study, the authors examined whether self-selection for antioxidant vitamin supplement use affects the incidence of age-related maculopathy. The study population consisted of 21,120 US male physician participants in the Physicians' Health Study I who did not have a diagnosis of age-related maculopathy at baseline (1982). During an average of 12.5 person-years of follow-up, a total of 279 incident cases of age-related maculopathy with vision loss to 20/30 or worse were confirmed by medical record review. In multivariate analysis, as compared with nonusers of supplements, persons who used vitamin E supplements had a possible but nonsignificant 13% reduced risk of age-related maculopathy (relative risk = 0.87, 95 percent confidence interval (CI) 0.53-1.43), while users of multivitamins had a possible but nonsignificant 10% reduced risk (relative risk = 0.90, 95% CI 0.68-1.19). Users of vitamin C supplements had a relative risk of 1.03 (95% CI 0.71-1.50). These observational data suggest that among persons who self-select for supplemental use of antioxidant vitamin C or E or multivitamins, large reductions in the risk of age-related maculopathy are unlikely. Randomized trial data are accumulating to enable reliable detection of the existence of more plausible small-to-moderate benefits of these agents alone and in combination on age-related maculopathy.

Adult↗
PubMed1998

A study on the relationship between antisense EGFR cDNA fragments and nuclear matrix proteins in glioblastoma cells.

The association of antisense epidermal growth factor receptor (EGFR) cDNA fragments with nuclear matrix from EGFR-antisense transfected glioblastoma cell lines U343 and U87 was investigated. A 1015 bp DNA fragment (primer I-II) was amplified in both genomic DNA and nuclear matrix-associated DNA (NM DNA) from EGFR-antisense transfected glioblastoma cell lines U343E and U87E. Two different DNA fragments (940 bp and 110 bp) were amplified by primer I-III in both genomic DNA and NM DNA of U343E, while one 110 bp PCR product was shown with the same primer in both genomic DNA and NM DNA of U87E only. After EGFR-antisense transfection, the binding property of the 110 bp DNA fragment (primer IV-V) to nuclear matrix was not affected. Southwestern blotting demonstrated the presence of antisense EGFR cDNA binding nuclear matrix proteins. Our findings demonstrate that not only EGFR DNA is associated with nuclear matrix, but the transfected antisense EGFR cDNA also binds to nuclear matrix proteins. The nuclear matrix is most likely involved in the replication and transcription of antisense EGFR cDNA or hybridisation with sense mRNA in vitro.

Brain Neoplasms↗
PubMed1996

Plasma cells with iron inclusions in two non-alcoholic Chinese women.

Plasma cells with iron granules are rare, especially among non-alcoholic individuals. We report two teetotaller Chinese women with nasopharyngeal carcinoma and non-Hodgkin's lymphoma, whose bone marrow studies revealed plasma cells with inclusions morphologically compatible with iron granules. The iron nature of the granules was confirmed by elemental analysis. The clinical significance and the exact mechanism of formation of these iron inclusions in plasma cells remain unknown.

Adult↗
PubMed1996

Ultrastructural calcification of glomerular immune complexes.

We report a previously undescribed ultrastructural calcification of glomerular immune complex depositions in a patient with lupus nephritis. Such processes give rise to a distinctive ultrastructural calcified microspheriol in electron-dense immune deposits, and were associated with hypercalcemia and nephrocalcinosis. The cause of hypercalcemia in this patient was uncertain, but related to a granulomatous inflammation and abscess of the breast. Whereas ultrastructural microcalcification was associated with hypercalcemia, its distribution in the segmental glomerular lesions suggests that an inflammatory process was contributory. The clinical follow-up indicates that the microcalcifications of immune complexes have not affected the outcome of nephritis and renal function.

Adolescent↗
PubMed1996

[Nuclear matrix-lamina-intermediate filament system in PtK 2 cells].

Selective extraction, whole mount cell preparation and DGD embeddment-free section were involved in visualizing the nuclear matrix-lamina-intermediate filament system in PtK 2 cells. After extraction the anaphase chromosome residues adjoined to the cytoplasmic intermediate filament in some areas. Immunofluorescent staining showed us that the intermediate filament reacted with AE 1 and AE 3; McAb 223 could be localized specifically on the lamina while McAb C 23 could crossreact with cytoplasmic intermediate filament beside the lamina location, monoclonal antibody against lamin A (C) could also bind to chromosome residues. Antibody to 280 kD nuclear matrix protein which were positive stained in HeLa cells could not react with the nuclear matrix components of PtK 2 cells. 2-D electrophoresis demonstrated that there were some differences in the composition of the nuclear matrix-lamina-intermediate filament system of HeLa and PtK 2 cells. TdR treatment could lead to alteration of nuclear matrix proteins.

Animals↗
PubMed1995

Characterization of human ovarian surface epithelial cells immortalized by human papilloma viral oncogenes (HPV-E6E7 ORFs).

Primary human ovarian surface epithelial (HOSE) cells were immortalized by a retroviral vector (LXSN-16E6E7) expressing HPV-E6E7 open reading frames (ORF). Immortalizations of primary ovarian epithelial cells were achieved in three of three attempts. Detailed analysis was carried out in one line, HOSE 6-3, selected on the basis of its epithelial morphology. The immortalized line (HOSE 6-3) was nontumorigenic in nude mice when examined at subculture number 20. Cytogenetic analysis confirmed its human origin and detailed karyotypic analysis revealed a mixed karyotype made up of about 60% of diploid and 40% of near-tetraploid cells. Clonal chromosomal aberration was observed in a subpopulation of cells involving a ring chromosome number 9. Immunofluorescence and two-dimensional gel electrophoresis revealed the presence of vimentin and several species of cytokeratin (K7, K8, K18, K19). The profile of the cytoskeletal filaments of HOSE 6-3 cells is largely identical with that of normal ovarian epithelial cells before immortalization. The immortalized ovarian epithelial cells have a lower sensitivity to TGF-beta 1 inhibition compared to normal ovarian epithelial cells. The immortalized line, HOSE 6-3, has altered growth properties including a higher proliferation rate, plating efficiency, and saturation density. The establishment of a continuous line of human ovarian epithelial cells may provide an in vitro model for study of carcinogenesis in human ovarian cancers.

Cell Division↗
PubMed1990

Establishment and characterization of a new human cell line derived from ovarian clear cell carcinoma.

A new cell line, designated OCC1, was established from the ascitic fluid of a patient with a clear cell carcinoma of the ovary. The cell line grew well without interruption for over 12 months and over 80 passages. The doubling times of OCC1 were 36 and 38 hr at the 10th and 40th passages, respectively. Chromosomal analysis of the cell line showed hypertriploidy with modal number around 70-77. Several structural chromosomal abnormalities were consistently found. Electron microscopy revealed that OCC1 produced a basement membrane-like structure in vitro. Histological evaluation of xenografts from OCC1 in the 33th passage implanted and grown in nude (athymic) mice revealed a morphology identical to that of the original tumor.

Adenocarcinoma↗
PubMed1987

Microwave fixation in diagnostic renal pathology.

Microwave-fixed tissues were examined in 10 patients undergoing diagnostic renal biopsy. A small portion of renal tissue was fixed by microwave irradiation and subsequently processed by routine methods for light microscopic, immunofluorescent and electron microscopic studies. The remaining portion of specimen was fixed and processed by conventional methods. In light microscopic examination, the renal architecture and cell morphology were well-preserved. Pathological changes were identical to those seen with formalin-fixed tissue. The pattern, distribution and intensity of positive immunofluorescence in microwave-fixed tissue were similar to those in tissues directly snap-frozen and stained. In electron microscopy, the normal and pathological features were well-demonstrated and not different from those observed in glutaraldehyde-fixed specimens. Specific ultrastructural lesions were clearly demonstrated and, apparently, were not altered by microwave irradiation. Our preliminary data indicate that microwave fixation can be effectively applied in the processing of renal biopsies. As the fixation is rapid, this method may be valuable in circumstances when an urgent diagnosis is required.

Biopsy↗
PubMed1986

Formation of rough endoplasmic reticulum and nuclear membrane in normal and tumour cells.

Paired cisternae have been found in normal and tumour cells both at interphase and mitosis being more common at the latter. It is believed that newly synthesized membranous protein and phospholipid molecules in the cisternae may polymerize spontaneously to form new membranes and as a consequence, multiplication of endoplasmic reticulum and nuclear membrane occur. Thus paired cisternae in interphase and mitotic cells may serve as a centre for the organisation of these two cellular organelles.

Animals↗
PubMed1984

Surface morphological study of Ehrlich ascites tumor cells exposed to microwave irradiation and heat.

Microwave irradiation of EAT cells caused an increase in length and number of surface microvilli. The tumor cells tend to form large aggregates by means of extensive interdigitation of surface microvilli. On the other hand, heat hyperthermia caused a decrease of surface microvilli but an increase of surface blebs. Hence the surface morphology of EAT cells after in vitro exposure to microwave irradiation differs markedly from that after heat hyperthermia.

Animals↗
PubMed1983

A fine structural study of microwave fixation of tissues.

Microwave fixed liver and kidney tissues were examined by electron microscopy. It was found that the preservation of fine structure of these tissues by this method is equal to that processed by routine methods. No difficulty was encountered in sectioning microwave fixed tissue blocks. It is obvious that microwave fixation is a faster and more efficient method.

Animals↗
PubMed1983

Ultrastructures of nerve fibers and muscle spindles in adolescent idiopathic scoliosis.

Muscle biopsies were obtained from the erector spinae to investigate ultrastructural changes in nerve fibers and muscle spindles in patients suffering from adolescent idiopathic scoliosis. Membranous bodies are found in myelinated nerve fibers, both within and outside the muscle spindles. Leptofibrils are formed beneath the sarcolemma of the intrafusal muscle fibers. Additionally, in the intrafusal muscle fiber, there are slight increases in the amount of lipid droplets and glycogen particles, and the sarcoplasmic reticulum is slightly dilated. These changes may affect the metabolism of the muscle fiber and the normal balance of the contractile system. The cause-and-effect relationship of the changes in adolescent scoliosis warrants further investigation.

Adolescent↗
PubMed1980

Establishment of a cell line (NPC/HK1) from a differentiated squamous carcinoma of the nasopharynx.

A long-term cell culture epithelioid cell line was established from a recurrent squamous carcinoma of the nasopharynx of a Chinese male 17 1/2 years after radiation therapy. The cell line, designated NPC/HK1, has been passed 72 times over a period 1 year. The cells have been shown by light and electron microscopies to be of the squamous epithelial type. When they were transplanted subcutaneously into the back of athymic nude BALB/c (nu/nu) mice, tumors developed at the sites of inoculation, which on histological examination were shown to be well-differentiated squamous carcinomas, similar in morphology to the recurrent human tumor from which they were derived. Karyotypic analysis of cells from the cell line demonstrates an aneuploid human type with a modal chromosome number of 74 with both numerical and structural aberrations. Viral particles or Epstein-Barr viral nuclear antigen (EBNA) has not been demonstrated in the cells from the primary culture or several of the subcultures tested. The presence of EBNA in touch smears prepared from the biopsy tissue was inconclusive. Infection of the subcultured cells with EBV from P3HR1 and B95-8 cells was unsuccessful.

Adult↗
PubMed1980

Membranous bodies in the myelin sheath of Schwann cells.

Electron microscopy of muscle biopsies of patients with paralytic scoliosis and tuberculosis of spines reveals membranous bodies in the myelin sheath of Schwann cells. On the basis of this morphological pattern and indirect biochemical evidence, it is suggested that these bodies were formed by abnormal myelin metabolism.

Humans↗
PubMed1980

Intracytoplasmic desmosomes in tumor cells.

The occurrence of intracytoplasmic desmosomes in some normal and tumor cells was suggested to develop by cell fusion by previous investigators. In this study, similar structures were found in tumor biopsies and tumor cells in culture. It is suggested that these structures develop by membrane incorporation and dissolution in cells with active membrane turnover.

Cell Membrane↗