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Biomedical subjects

M Emura

Publications and source records attributed to M Emura.

At least 73 records · Page 4Linked to original sources
PubMed1986

A fetal Syrian hamster lung epithelial cell line as an in vitro model for respiratory carcinogenesis.

A clonal continuous cell line consisting of pre-differentiated lung epithelial cells was established from a Syrian golden hamster fetus on day 15 of gestation. Immunocytological techniques revealed cytoplasmic filaments positive to antikeratin antibody and positive to antivimentin antibody in these cells. Supplementation of the medium with epidermal growth factor, insulin, other types of hormones and vitamin A markedly enhanced cell growth and DNA synthesis. Simultaneously, the cell differentiation characterized by mucus-like glycoprotein production was greatly stimulated. Removal of vitamin A diminished cell growth and this differentiation. The cell system was found to be useful for studying the relationship between in vitro cell transformation and differentiation. Additionally, studies to define general chemical toxicities in this cell system by evaluating several parameters such as cell survival, sialic acid content and enzyme leakage into the medium are in progress.

Animals↗
PubMed1986

Blood detoxification by membrane plasma filtration.

The recognition of macromolecule abnormalities in various metabolic or immunologic related disease states has led to the use of plasma exchange for therapeutics. Limitations of plasma exchange, however, exist. Membrane plasma filtration provides a practical alternative. Solute removal can be made selective by the choice of operating conditions as temperature and the selection of the membrane/module design. The optimal temperature range is a function of the plasma type, solute concentrations and membrane system. Operation at below physiologic temperature (cryofiltration) is particularly suited for the removal of cold aggregative solutes, while operation at near or above physiologic temperature is more suited for the separation of solutes having large size differences at normal physiologic temperature. Membrane filtration is simple and safe to perform, is more selective than plasma exchange, does not require plasma product infusion and is more versatile than selective sorption in its applications.

Blood↗
PubMed1985

Importance of coronary collaterals for restoration of left ventricular function after intracoronary thrombolysis.

In an evaluation of the role of coronary collaterals in the early period of acute myocardial infarction (AMI), 30 patients with acute total coronary occlusion treated with intracoronary thrombolysis 2 to 8 hours after the onset of symptoms were studied. Only 13 patients with well-developed collaterals in the early period of AMI and successful thrombolysis showed improvement of global and regional ejection fraction (EF) from the acute phase to the chronic phase (global EF from 50% to 71%, p less than 0.001; regional EF from 25.4% to 49.2%, p less than 0.001). In patients with no or less well-developed collaterals and successful thrombolysis, global and regional EF were similar to those in patients in whom thrombolysis was unsuccessful. Among the 19 patients with successful thrombolysis, there was no significant correlation between the duration of ischemia and the improvement of regional EF (r = -0.03, difference not significant). These data suggest that the extent of coronary collateral vessels in the early period of AMI is an important determinant of restoration of left ventricular function after intracoronary thrombolysis.

Acute Disease↗
PubMed1985

The use of cell and organ culture from the respiratory tract for testing chemicals.

For the toxicity testing of compounds using tissue from the respiratory tract, three types of in vitro cell or tissue culture systems are being developed from foetal Syrian hamster respiratory organs on day 15 of gestation. The first system, early-passage cell cultures of a mixed population obtained from foetal lungs, has been used frequently for the study of in vitro cell transformation. The clonal culture technique using these cells permitted the semi-quantitative determination of the toxicity of poly- or heterocyclic hydrocarbons in terms of the reduction in the number of surviving colonies. The second system, an explant culture technique using foetal tracheae, demonstrated the induction, by polycyclic hydrocarbons, of alterations such as hyperplasia, epidermoid metaplasia or dysplasia of mucociliary epithelia. The third system uses the cells of a permanent clonal epithelial cell line established from the foetal lung. These cells differentiated into a mucus-producing cell type in a medium supplemented with vitamin A and hormone. In order to observe general aspects of toxicity in these cells, they were exposed first to model substances such as sulphuric acid and potassium dichromate. After 24 hr of post-exposure incubation, the activities of membrane-bound and cytosolic enzymes, the amount of sialic acid released into the medium and cell survival were measured. Based on the results obtained so far, the potential value of each system is discussed.

Animals↗
PubMed1985

Growth inhibition and transformation of a human fetal tracheal epithelial cell line by long-term exposure to diethylnitrosamine.

In order to obtain more information on the in vitro transformation of human cells, a human fetal tracheal epithelial cell line (FHET16/5) was exposed for a long time to diethylnitrosamine (DEN). In 20 passages, this cell line (diploid, male) maintained strong immunohistochemical reactivity for carcino-embryonic antigen and wool merokeratin; it was negative for vimentin. The cells contained PAS-positive mucous substances and ultrastructurally were found to have desmosome-like attachments. Treatment of the cells was with 0.3% dimethyl sulphoxide (DMSO), or DMSO with 150, 450, 1000 or 2000 micrograms/ml of DEN. It was started at the ninth passage and continued for six passages over 9 weeks for the control (DMSO) and the three lowest control doses of DEN, and for three passages over 9 weeks for the 2000 micrograms/ml DEN group. Cells grown for 13 days after the end of treatment were plated in soft agar and injected subcutaneously in nude mice. The frequency of anchorage-independent colonies grown in soft agar was directly related to DEN dose. Colony-forming efficiency, as an expression of toxic effect, was also dose dependent. Autoradiographically detected unscheduled DNA synthesis indicated an association between anchorage-independent transformation and DNA alterations induced by DEN. Cells injected into nude mice did not produce tumours during a 6-month period, but invasiveness was observed when cells from the 2000 micrograms/ml DEN group were transplanted on the dermis of cultured chick embryo skin. The results indicate that DEN causes anchorage-independent transformation accompanied by unscheduled DNA synthesis in a fetal human tracheal epithelial cell line.

Animals↗
PubMed1985

Clinical thermofiltration: initial application.

The first clinical thermofiltration procedures (plasma filtration near or above normal physiologic temperature) were performed on a secondary hypercholesterolemia patient. The intent of this filtration scheme is the selective removal of low density lipoproteins (LDL) and maintenance of high density lipoproteins (HDL) and other essential plasma proteins including albumin. The EVAL 4A filter, at a filtration temperature of 37 degrees C, was selected for on-line thermofiltration. The sieving coefficients of LDL + very low density lipoproteins (VLDL) cholesterol, HDL cholesterol, and albumin were 0.02, 0.75, and 0.78, respectively. These results are comparable to in vitro filtration tests using the plasma of the same patient. This system is simple to apply and does not require replacement solution. Compared with plasma exchange, a high return of HDL and other essential plasma solutes can be returned to the patient by this method.

Adult↗
PubMed1985

Apheresis: clinical response to patients unresponsive to conventional therapy.

Ten of 13 (76.9%) rheumatoid arthritis (RA) patients having intensive cryofiltration treatment showed improvement and 5 of 7 (71.4%) of RA patients treated on maintenance cryofiltration therapy showed improvement. Encouraged by these results, 2 centers were established for controlled trial studies of RA patients. Four of 4 (100%) rheumatoid vasculitis patients treated by cryofiltration and 4 of 7 (57.1%) patients treated with plasma exchange showed clinical improvement. An SLE patient with thrombocytopenia showed a dramatic rise in platelet count during intensive (3 day/wk) plasma exchange treatments despite little prior response to drugs, platelet infusions and splenectomy. Plasmapheresis was effective in improving clinical symptoms and lipid abnormalities in a primary sclerosing cholangitis patient without causing hypoproteinemia during the long-term therapy (4 yrs).

Adult↗
PubMed1985

Scanning electron microscopical investigations on the respiratory epithelium of the Syrian golden hamster. VI. In vitro effects of different polycyclic aromatic hydrocarbons.

In a comparative study, the biological effects of different polycyclic aromatic hydrocarbons (PAH) on the fetal respiratory epithelium of Syrian golden hamsters were examined (light and scanning electron microscopy) in tracheal explants exposed in vitro to benz(a)anthracene (BaA), benz(a)acridine (BaAC), benzo(b)fluoranthene (BbF), benzo(e)pyrene (BeP), benzo(k)fluoranthene (BkF) and pyrene (PYR). Concentrations of the compounds related to the solubility in dimethylsulphoxide in the tissue culture medium (0.5% DMSO). Focally slight inhibition of epithelial differentiation and/or circumscribed simple metaplasia with an incidence of up to 10% were found in the controls (0.5% DMSO), BeP and PYR groups as well as in the explants exposed to low levels of BaA and BaAC. The frequency of these lesions increased with raising (doubling) the dose (50%: BaAC, BbF, BfK; 100%: BaA). Following exposure to the latter compounds a similar dose response relationship was observed for dysplastic alterations of the respiratory epithelium. In some of these cases (10%) the epithelial change was associated with focally hyperplastic and/or proliferative exophytic growth. Morphologically, the alterations were comparable to those representing early changes associated with the development of epidermoid and mucoepidermoid neoplasms found after in vivo PAH exposure. In terms of transformation, the data support the information obtained from observations on mixed fetal hamster lung cells exposed to the same compounds.

Animals↗
PubMed1983

Transplacental effect of N-diethylnitrosamine on chromosomal aberrations in fetal tracheal cells of the Syrian hamster: comparison between epithelial and mesenchymal cells.

Chromosomal aberrations were investigated in tracheal cells of fetal Syrian hamsters after transplacental administration of N-diethylnitrosamine (DEN). On the 15th day of pregnancy, Syrian hamsters were injected s.c. with a tumorigenic dose of DEN (50, 100 and 200 mg/kg body weight). Two hours later, the fetal tracheae were isolated, the epithelial tissue was separated from the mesenchymal tissue by collagenase-treatment, and then each cell population was transferred to cell culture after Dispase treatment. At 24, 48 and 72 h after the cell cultivation, chromosomal damage was examined. The results clearly showed that a high incidence of chromosomal aberrations, especially chromatid-type exchanges, was seen in the epithelial cells of DEN-treated groups. However, significant induction of chromosomal aberrations was not observed in the mesenchymal cells from DEN-treated groups.

Animals↗
PubMed1983

Assessment of nitrosamine transplacental carcinogenesis in the Syrian golden hamster.

The effects of diethylnitrosamine (DEN) and vinylethylnitrosamine (VEN) in the F1 generation of Syrian golden hamsters are described after the compounds were administered to the P generation during the second half of pregnancy. Morphologic findings revealed that the upper respiratory tract (i.e., trachea) was most affected. VEN appeared highly effective because the first neoplastic alterations (papillary polyps) were seen in both the P and the F1 animals at the 30th postnatal day. The fetal tracheal epithelium also showed chromosomal aberrations after DEN exposure, and VEN enhanced the cloning efficiency of these cells. Combined in vivo - in vitro studies are discussed with special emphasis on the early detection of transformation and neoplastic growth.

Animals↗
PubMed1982

A fetal respiratory epithelial cell line for studying some problems of transplacental carcinogenesis in Syrian golden hamsters.

Using repeated cloning and treatment with cis-HPL (200 micrograms/ml), an analogue of a procollagen precursor inhibitory to the growth of collagen-synthesizing cells of mesenchymal origin, clonally premature epithelial cell lines were isolated from fetal SGH lungs cultured on the 15th day of gestation. One of the cell lines, M3E3/C3, which has been extensively studied for biological characterization, developed poorly differentiated carcinomas in injected hamsters after transformation by MNNG. Moreover, when grown on collagen gel, this cell line indicated an obvious potency for in vitro differentiation in response to vitamin A by developing activated Golgi regions, well developed rER and a number of mucus-like granules. Since such a differentiative responses is expected to be definable in the light of respiratory epithelium developing in utero, this cell line may be useful for studying mechanisms of differentiation-dependent sensitivity of fetal organs to transplacental carcinogen exposure.

Animals↗
PubMed1982

Chromosomal aberrations in tracheal epithelial cells of the fetal Syrian golden hamster after transplacental N-diethylnitrosamine administration.

Transplacental effect of N-diethylnitrosamine (DEN) on chromosomal morphology, was investigated in fetal tracheal epithelium of Syrian hamsters. At the 15th day of pregnancy, Syrian golden hamsters were injected subcutaneously with a tumorigenic dose of DEN (50, 100 and 200 mg/kg body wt). Two hours later, the fetal tracheae were isolated, epithelial cells of the respiratory mucosa were separated from mesenchymal tissue and were transferred to cell culture. At 24, 48 and 72 h after cultivation, chromosomal damages were examined. The results showed clearly that a high incidence of chromosomal aberrations, particularly chromatid-type exchanges, were seen in the epithelial cells from DEN-treated groups.

Animals↗
PubMed1982

Scanning electron microscopical investigations on the respiratory epithelium of the Syrian golden hamster: transplacental effects of vinylethylnitrosamine.

The transplacental effect of vinylethylnitrosamine (VEN) on the respiratory epithelium of Syrian golden hamsters was tested after administration of 5 and 10 mg VEN/kg b.w. dissolved in olive oil at the 12th or 15th day of gestation. The morphological data, obtained mainly by scanning electron microscopy on tracheae revealed metaplastic and hyperplastic epithelial changes, as well as focal exophytic papillary proliferations at the 30th postnatal day in the group treated at the 15th day of gestation. No comparable lesions were found in the trachea of the F1 generation when mothers were treated with VEN at day 12 of pregnancy or in animals of the control group (olive oil only). The biological effects of VEN after transplacental exposure were compared to those of other nitrosamines.

Animals↗