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Biomedical subjects

A G Papayannis

Publications and source records attributed to A G Papayannis.

At least 19 recordsLinked to original sources
PubMed1981

Effect of ionizing radiation on platelet function in vitro.

The effect of ionizing radiation on platelet function was investigated in vitro. Platelet-rich plasma (300 x 10(9/1)) was irradiated with doses of 1, 4, 10, 20 and 50 Gy. Platelet function tests were performed on both irradiated and control (non-irradiated) platelet samples. The platelet function tests were (1) platelet aggregation by ADP (1, 2, 4 mumol final concentration), adrenaline and collagen, (2) ADP-release from platelets, (3) clot retraction and (4) platelet factor-3 availability. It was found that roentgen irradiation of platelets in vitro did not affect these platelet functions tests.

Adenosine Diphosphate↗
PubMed1977

Platelet function tests during major operation for gastro-intestinal carcinoma.

Platelet function tests were performed on 15 patients undergoing major operation preoperatively, during anaesthesia and 30 minutes and 3 hours after the beginning of operation. It was found that during anaesthesia platelet retention in a glass bead column and platelet aggregation were slightly reduced. During operation the bleeding time and the delay period of the collagen-induced aggregation were progressively prolonged, and the aggregation induced by ADP at a final concentration of 1 and 2 micrometer and by adrenaline was progressively reduced.

Adult↗
PubMed1977

Platelet function, blood coagulation and fibrinolysis in Behcet's syndrome.

In 10 patients with Behcet's syndrome, various parameters of platelet function, blood coagulation and fibrinolysis were studied. With varying frequency the following abnormalities were found: increased retention of platelets in glass bead column, reduced platelet aggregation to low concentrations of adenosine diphosphate, elevated plasma levels of fibrinogen concentration and factor VIII activity, increased plasma antiheparin activity and impairment of fibrinolytic activity. The above abnormalities were found long after the last thrombotic episode and were more frequent in patients with a history of thrombophlebitis. It is suggested that certain hemostatic abnormalities accompany or form part of Behcet's syndrome and that they are related to the thrombotic complications characteristic of this syndrome.

Adenosine Diphosphate↗
PubMed1977

Cytogenetic studies in preleukaemia using the G-banding staining technique.

15 patients with preleukaemia were cytogenetically studied during the preleukaemic state by using the G-banding staining technique. It was found that 9 patients had a completely normal karyotype, while the other 6 showed various chromosomal abnormalities, numerical (trisomies in 5 cases) and structural (deletion in 1 case and a marker chromosome in 1 case). The abnormalities concerned group C in all 6 cases, while group A was involved in 3 cases. G-banding technique revealed that trisomy C affected the chromosomes nos 8 (2 cases) and 9 (3 cases); also a deleted chromosome 11 (11q-) was identified in 1 case and a marker chromosome in 1, the origin of which was established as a translocation between chromosomes 3 and 6. The abnormalities of group A concerned chromosome no 3. The abnormalities found in our cases, using the G-banding technique, were similar to those described in acute leukaemia.

Aged↗
PubMed1977

Familial thrombosis due to antithrombin III deficiency in a Greek family.

A Greek family with hereditary antithrombin III (AT III) deficiency associated with venous thrombosis is reported. 5 members of the family were affected. In these patients, AT III and heparin cofactor activities were decreased. Immunoreactive AT III showed a positive correlation to both AT III and heparin cofactor activities. alpha2-Macroglobulin and alpha1-antitrypsin were normal. The pattern of inheritance of the defect is autosomal dominant.

Adult↗
PubMed1977

Postoperative platelet function in patients on small subcutaneous doses of heparin.

Several platelet function tests were performed on 31 patients undergoing major operations, who recieved prophylactically small subcutaneous doses of heparin. A group of 15 similar patients without heparin served as controls. It was found that postoperatively in both groups (a) the platelet retention in glass bead column was significantly increased (p less than 0.001), (b) the platelet aggregation by ADP 1 micronM was slightly increased, (c) the collagen-induced aggregation, ADP release and the bleeding time remained unchanged and (d) the platelet counts decreased in the first 2 postoperative days and increased thereafter. There was no difference between patients on heparin and controls.

Adenosine Diphosphate↗
PubMed1976

Increased proportion of B lymphocytes in human tonsils and appendices.

The percentage of T and B lymphocytes was studied in human tonsils and appendices. An increased percentage of B lymphocytes, 59.1% in tonsils and 54.5% in appendices, was found, whilst the percentage of T lymphocytes was 23.6% and 27.9%, respectively. In the peripheral blood of the corresponding figures were 12.5% for B cells and 50% for T cells.

Appendix↗
PubMed1975

Hypercoagulability and hypofibrinolysis in sickle-cell disease.

Fifty-two patients with sickle-cell (SC) disease (48 with SC-beta-thalassaemia and 4 with homozygous SC-anaemia) were studied as regards blood coagulation and fibrinolysis. It was found that the thrombin and the reptilase times of the patients' plasma were significantly shorter than normal. The mean values of platelet count, fibrinogen level and factor VIII activity of patients with SC disease were higher than normal; however, in the group of patients transfused, with less than 50% haemoglobin S (HbS), the fibrinogen level and the factor VIII activity were significantly lower compared to the other patients. Antithrombin-III (At-III) activity was normal in all. The fibrinolytic activity was normal in patients with asymptomatic SC disease, but reduced in patients on painful crises. Plasminogen and fibrinogen/fibrin degradation product (FDP) levels were normal in all patients. Two patients on painful crises with complications had additional abnormal findings, namely prolonged prothrombin time, reduced At-III level and elevated FDP.

Adolescent↗