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Biomedical subjects

L Chen

Publications and source records attributed to L Chen.

At least 1,549 records · Page 86Linked to original sources
PubMed1977

Differentiation of decidual cells in cultures of rat endometrium.

Endometrial scrapings were collected from rat uteri at various times (0-4 days) after induction of a decidual reaction by i.p. injection of pyrathiazine hydrochloride (20 mg/animal) on the 5th day after a sterile mating. The tissue was dissociated by treatment with trypsin and the cells were cultured as monolayers. The differentiation of decidual cells was followed in these cultures. Two morphologically distinct cell populations were recognized: (i) dispersed spindle-shaped or stellate cells, and (ii) colonies of closely packed polygonal cells, first apparent after 48 h in culture. During culture, [3H] thymidine was incorporated into the nuclei of both cell types, as indicated by autoradiography. There was an increase in the number of cells in the colonies as culture progressed; most mitotic figures and the highest % of labelled nuclei were located within the colonies. Bi- and multinucleated cells, which are a characteristic feature of decidual tissue in vivo, appeared in the colonies on the 3rd day of culture and constituted about 60% of the colony population after 4-5 days. The dispersed cells showed a doubling in nuclear area during 4 dyas in culture, suggesting the formation of polyploid cells; such cells are prominent in fully differentiated decidual cells in vivo. The content of prostaglandin E in the cultured cell, determined by radioimmunoassay, was about 15-fold higher than that in rat embryo fibroblast cultures grown under similar conditions, and was comparable to the level of prostaglandins found in decidual cells in vivo.

Animals↗
PubMed1975

Habituation and inhibition of the crayfish lateral giant fibre escape response.

1. Decrement of the lateral giant fibre escape response was studied in intact, restrained, crayfish and in those with the ventral nerve cord transected at the thoracic-abdominal level. 2. Taps (delivered at rates of 1 per 5 min to the abdomen) depressed responsiveness to about 50% of its inital value in 10 trials, for both intact and operated animals. 3. With additional stimulation, responsiveness dropped to near zero for both groups. Recovery was negligible 2 h later, but nearly complete after an additional 24 h rest. 4. Protection against response decrement in this situation was obtained by directly activating the cord giant fibres 30 msec prior to the tactile stimulus. The directly-elicited giant fibre spikes which follow the tactile stimulus do not influence the course of response decrement. 5. The results establish the decrement as centrally mediated habituation, and minimize the role of receptor alterations or descending neuronal influences in the behavioural change. 6. A comparison is made between the properties of hibituation and the homosynaptic depression of afferent to interneurone synapses that is presumed to be the physiological mechanism of habituation in this situation.

Animals↗
PubMed1970

Further studies of the effect of bone marrow cells on chemically induced lymphoma in C57BL-6 mice.

Injection of syngeneic bone marrow cell to adult C57BL/6 mice treated DMBA intragastrically failed to prevent lymphoma induced by the chemical.The present result seem to indicate that bone marrow cells do not hasten the regeneration of the transient injuried thymus by DMBA as compared with their effect in irradiated mice.IT APPEARS THAT, UNDER THE CONDITIONS USED, DMBA DOES NOT CAUSE SIGNIFICANT DAMAGE TO THE BONE MARROW SINCE MARROW CELLS FROM CHEMICALLY TREATED MICE WERE AS EFFECTIVE AS NORMAL MARROW CELLS IN: (a) preventing radiogenic leukaemia, (b) repairing radiation damage of the thymus, (c) preventing the lethal action of high doses of irradiation.Marrow cells failed to restore antibody formation to Shigella depressed by DMBA as they do in irradiated mice.The result strengthen our previous view on the critical role of bone marrow on the effects caused by irradiation and not in the leukaemia process as such.

Animals↗
PubMedDate not supplied

Bioavailability of selenium from veal, chicken, beef, pork, lamb, flounder, tuna, selenomethionine, and sodium selenite assessed in selenium-deficient rats.

The bioavailability of selenium (Se) from veal, chicken, beef, pork, lamb, flounder, tuna, selenomethionine (SeMet), and sodium selenite was assessed in Se-deficient Fischer-344 rats. Se as veal, chicken, beef, pork, lamb, flounder, tuna, SeMet, and sodium selenite was added to torula yeast (TY) basal diets to comprise Se-inadequate (0.05 mg Se/kg) diets. Se as sodium selenite was added to a TY basal diet to comprise a Se-adequate (0.10 mg Se/kg), Se-control diet. The experimental diets were fed to weanling Fischer-344 rats that had been subjected to dietary Se depletion for 6 wk. After 9 wk of the dietary Se repletion, relative activity of liver glutathione peroxidase (GSHPx) from the different dietary groups compared with control rats (100%) was: flounder 106%, tuna 101%, pork 86%, sodium selenite 81%, SeMet 80%, beef 80%, chicken 77%, veal 77%, and lamb 58%. Se from flounder was the most efficient at restoring Se concentrations in the liver and skeletal muscle. Se from sodium selenite, SeMet, beef, veal, chicken, pork, lamb, and tuna was not dietarily sufficient to restore liver and muscle Se after 9 wk of recovery following a 6-wk period of Se depletion.

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