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Biomedical subjects

C Davis

Publications and source records attributed to C Davis.

At least 415 records · Page 23Linked to original sources
PubMed1971

Lingual thyroid.

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Child↗
PubMed1970

Preparation of beating heart cells from adult rats.

Suspensions of cardiac cells have been prepared from fragments of hearts from adult rats by prolonged incubation with trypsin and collagenase. In these preparations, about 50 percent of the viable cells routinely exhibit spontaneous contractions ranging from 20 to 120 beats per minute at room temperature. The contractile activity is essentially lost at 2 degrees C but returns to normal as the temperature is increased. The rate of cellular contractions and the percentage of total cells exhibiting contractility are influenced by experimental conditions of cell preparation and the composition of the suspending medium.

Animals↗
PubMed1969

Pruritus ani.

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Chronic Disease↗
PubMed1968

The thymus and recovery of the sheep erythrocyte response in irradiated mice.

The role of the thymus in the recovery of the sheep erythrocyte response after lethal irradiation has been studied in adult CBA mice with the hemolytic plaque technique of Jerne. This immunological parameter is markedly thymus-dependent. 10 wk after irradiation and after antigenic challenge the thymectomized animal has only one-twentieth to one-fortieth the number of plaque-forming cells as does the irradiated animal with intact thymus. The thymus continues to function into the 7th and 8th month of life in this strain. Unlike the drug-tolerant animal, the incompetent irradiated thymectomized mouse retains base line plaques (plaques without antigenic stimulation). Thymectomy 18 days after irradiation is as effective as prior thymectomy in preventing recovery of the sheep cell response. Thymectomized animals receiving grafts of isogenic neonatal thymus (placed beneath the kidney capsule) 1 day, 1 wk, or 2 wk after irradiation are somewhat more responsive at 10 wk than intact animals. Grafts in place for 1 or 2 wk after irradiation and then removed result in one-fifth the recovery of grafts in place the entire time, while only slight restoration is obtained from grafts in place for the final 3 wk of the experiment. The results indicate that the thymus is not required for the 18 days after irradiation, that a period of at least 3 wk residence is required for complete restoration, and that the thymus itself is somewhat radiation-sensitive. Allogeneic thymus grafts failed to restore the hemolysin response of irradiated thymectomized animals.

Age Factors↗
PubMed1968

The thymus and recovery from cyclophosphamide-induced tolerance to sheep erythrocytes.

Recovery from specific immunological tolerance to sheep erythrocytes induced with the drug cyclophosphamide was studied with the hemolytic plaque technique of Jerne. The base line plaque (19S antibody-forming cell of the unstimulated spleen) and the proliferative response to antigen, both of which had disappeared during tolerance induction, returned with the recovery of specific immunological reactivity. When cyclophosphamide is injected without sheep cells there is temporary immunological unreactivity and lymphoid depletion of the spleen, but specific tolerance is not induced. Recovery is largely complete at the end of 2 wk and does not require the participation of the thymus. When cyclophosphamide is injected together with sheep cells, 18 days after drug injection, tolerance is still complete. In nonthymectomized mice there is rapid recovery during the next 10 wk, followed by much slower restoration over the remaining 20-30 wk of observation. The entire recovery process evidently takes 40-50 wk. In thymectomized CBA mice only minimal recovery takes place in the first 10 wk and no further restoration occurs thereafter. Thymectomy performed 18 days after tolerance is induced, when tolerance is complete, is equally effective in preventing this recovery.

Animals↗
PubMedDate not supplied

The effect of cytokines on cultured mononuclear cells from patients with B cell chronic lymphocytic leukemia.

In the past 5 years a number of cytokines have been identified that control B cell development, proliferation, and maturation. The role of such cytokines in the evolution, pathophysiology, and treatment of B cell malignancies is an area of great interest. The in vitro response of freshly isolated peripheral blood mononuclear cells from patients with B cell chronic lymphocytic leukemia (B-CLL) and a high white cell count, to four cytokines, IFN-alpha, IFN-gamma, IL-2 and TNF, was studied. No culture condition or cytokine resulted in a significant increase in cell number over 4 days, cells survived better in autologous serum than in heat inactivated foetal calf serum, and a small but significant increase in blast cells was seen when the cells were cultured in IL-2. There was a discrepancy between uptake of thymidine and increase in cell number which can be explained by the low labelling index of these cultures and the fact that cells can incorporate [3H]-thymidine without going into mitosis. The majority of cultures produced biologically active TNF at levels ranging from 1 to 40 pg/ml. In IFN-alpha treated cultures TNF levels were decreased. Cultures contained biologically active IL-6 at levels ranging from 2 to 2800 U/ml. IL-6 production was not influenced by other cytokines. Thirteen of 28 patients had detectable IL-6 in their serum, but in cells lysed no more than 2 h after removal from the patient, message for IL-6 could not be detected by Northern blotting. Cells also failed to express IL-1 beta mRNA but seven of eight patients had low levels of TNF message. Preliminary data using in situ hybridization techniques revealed that whilst no mRNA for IL-6 was detected, TNF and IL-1 beta mRNA were detected in a minority of mononuclear cells.

Antigens, Neoplasm↗
PubMedDate not supplied

Interactive activation accounts of morphological decomposition: finding the trap in mousetrap?

Many accounts of the processing of morphologically complex words have been elaborated within the interactive activation model of word identification. Conceptually, this model adopts a "segmentation-through-recognition" approach to morphological decomposition, which assumes that a complex word activates representations of constituent morphemes as well as the representation of the whole word. However, a detailed consideration of the assumptions of interactive activation frameworks reveals that current implementations of the model are incapable of achieving segmentation-through-recognition.

Cognition↗