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Biomedical subjects

A Pappas

Publications and source records attributed to A Pappas.

At least 37 records · Page 2Linked to original sources
PubMed1979

[Pre-operative irradiation and tumor-specific immune response in hypernephroid renal carcinoma (author's transl)].

In vitro demonstration of a tumor-specific immune response was tried using the so-called leucoycte migration test in altogether 32 patients with a hypernephroid renal carcinoma (nontreated before operation or pre-irradiated). The principle of this technique consists in the release of a lymphocyte factor by bringing in contact sensitized lymphocytes with the concerned tumourous tissue, the lymphocyte factor inhibiting the migration capacity of granulocytes. With hypernephroid cancerous tissue from nontreated patients no reaction was obtained in 12 of 13 cases (no inhibition of migration), whereas a positive reaction (inhibition of leuococyte migration) was observed in 17 out of 19 patients with hypernephromas having been irradiated before surgical treatment. This radiation-induced effect on the immune response from hypernephroma and lymphocytes in patients with this neoplasm is specific, as no reaction of irradiated hypernephroid cancerous tissue with lymphocytes of sound donors or of patients with different malignant tumors could be shown in control tests, a significant inhibition of leucocyte migration failing to appear.

Adenocarcinoma↗
PubMed1979

[Tumor-specific immune response of hypernephroid renal carcinoma after in vitro irradiation (author's transl)].

It is possible to reproduce in vitro the induction in the leucocyte migration test of an immune response specific to hypernephroid carcinoma by preoperative radiation treatment of this neoplasm. The leucocyte migration is inhibited by soluble extracts of the tumor, prepared from hypernephroma-tissues (of 11 patients nontreated preoperatively) after in vitro irradiation either with electrons or with 60Co. This effect depends on the dose. The radiation dose producing a maximal inhibition following in vitro irradiation is nearly equal to that delivered by us before surgical treatment.

Adenocarcinoma↗
PubMed1977

A micro-method for PHA-induced stimulation of human lymphocytes. II. communication: effect of splenectomy on the inhibitory activity of serum in patients with Hodgkin's disease.

Lymphocytes of 19 unselected patients with Hodgkin's disease were stimulated with PHA in vitro using a microculture system. The sera of these donors were simultaneously tested for their ability to support PHA-induced stimulation of normal lymphocytes as compared to sera drawn from healthy volumteers. Wheras DNA synthesis in Hodgkin's disease using normal sera was almost uniformly decreased, transformation of normal lymphocytes was suppressed in 9 of 11 sera from patients with Hodgkin's disease without splenectomy, but only in 1 of 8 sera from patients tested after removal of the spleen. 3 donors could be tested both before and after splenectomy, 2 showed a complete disappearance of inhibiting substances in their sera. These findings are discussed as to the immunological significance of inhibiting factors and splenectomy in Hodgkin's disease.

Hodgkin Disease↗
PubMed1975

Phytohaemagglutinin-induced lymphocyte transformation and histologic findings in patients with chronic aggressive hepatitis before and during immunosuppressive therapy.

In vitro lymphocyte transformation (14C-thymidine incorporation rate following stimulation by PHA) was studied in 19 patients with histologically proven chronic aggressive hepatitis. In the majority of the cases measurements were performed prior to and during a combined (azathioprine/corticosteroid) immunosuppressive therapy. In comparison to normal controls, the majority of the patients showed a significantly reduced lymphocyte transformation before the treatment started. During the immunosuppressive therapy there was a normalization of PHA-responsiveness in most of the patients, or an improvement, at least. Bioptic control seems to be the most reliable parameter to prove a therapeutic effect, since the histologic criteria for a decrease of the inflammatory activity were the last to occur. After transient cessation of the therapy, in 4 out of 6 cases a decrease of lymphocytic PHA-responsiveness was developed again, paralleled by histologic activation of the process where biopsy could be performed. This observation favours a long-term therapy for at least several years.

Adult↗
PubMed1975

[A micro-method for PHA-induced stimulation of human lymphocytes. I. Communication: Technical considerations (author's transl)].

A microculture system is described for PHA-induced stimulation of human peripheral lymphocytes. Following purification on Ficoll-Isopaque cells are incubated in microplates (Falcon 3040) for 66 hours in 5% CO2 using PHA-P (Difco) as a stimulant. DNA-synthesis is measured by labelling with 3H-thymidine (spec. act. 400 mCi/mmole) 16 hours prior to the end of the test. Using a multiple automatic sample harvester rapid evaluation is possible. Several variables were analyzed and optimal conditions defined for PHA- and cell-concentration, time dependence, thymidine dosage and buffer capacity of the medium. High variability and otherwise unexplained loss of lymphocyte stimulation in a population of "normal donors" are often due to acute viral infections, especially during the incubation period. On the other hand, source and concentration of serum are of equal importance since sera of healthy individuals differ greatly in their capacity to support PHA-induced stimulation of normal allogeneic lymphocytes. Using pooled or autologous serum we found the reproducibility of the technique to be good. Provided optimal conditions are employed the microtest system described herein should be ideal for in-vitro-analysis of inhibitory or stimulating factors in cancer patients' sera.

Adult↗