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Biomedical subjects

F Tzortzatou

Publications and source records attributed to F Tzortzatou.

5 recordsLinked to original sources

Electrolyte abnormalities in lymphosarcoma after chemotherapy.

A 12-year-old female with lymphosarcoma responding to treatment including vincristine and cyclophosphamide developed clinical and laboratory findings compatible with the syndrome of inappropriate secretion of antidiuretic hormone. Some additional findings were observed, i.e. uremia, hypopotassemia and alkalosis, that have not so far been recorded in that syndrome. All abnormalities were corrected upon water restriction. A similar episode occurred after a 2nd drug course. It too was corrected upon water restriction. The patient was clinically free from her malignancy in both episodes. It is suggested that our child had probably an expanded form of the syndrome of inappropriate secretion of antidiuretic hormone.

Child

Cytochemical demonstration of dihydrofolate reductase in leukaemia and other haematological diseases.

The dihydrofolate reductase activity has been studied cytochemically in various haematological diseases. The variation between normal controls, Hodgkin's disease, myeloma, polycythaemia vera, chronic lymphocytic leukaemia and chronic myeloid leukamia was not significant, comparing the same type of cells. In acute myeloid leukaemia and acute lymphoblastic leukaemia the blast cells were weakly positive or negative. This finding is very interesting as the blast cells are capable of division. Probably the dihydrofolate reductase appears in the blast cells in some stage of mitosis. Lymphocytes stimulated by phytohaemagglutinin showed increased enzyme activity compared with normal non-stimulated lymphocytes. The "blast like" cells were more strongly positive than the blast cells of leukaemic patients. The patients with acute lymphoblastic leukaemia or acute myeloid leukaemia treated with methotrexate showed increased dihydrofolate reductase activity cytochemically.

Hematologic Diseases

Cytochemical demonstration of 5-formyl tetrahydrofolate cyclodehydrase and 5,10-methenyl tetrahydrofolate cyclohydrolase activity.

The enzyme 5-formyl tetrahydrofolate cyclodehydrase plays an important role in the conversion of 5-formyl tetrahydrofolate to 5,10-methenyl tetrahydrofolate. A second enzyme, cyclohydrolase, converts 5,10-methenyl tetrahydrofolate to 10-formyl tetrahydrofolate. These folate derivatives play a significant part in the biosynthesis of purines. A method has been devised for the cytochemical demonstration of 5-formyl tetrahydrofolate cyclodehydrase and 5,10-methenyl tetrahydrofolate cyclohydrolase activity which uses 5-formyl tetrahydrofolate or 5,10-methenyl tetrahydrofolate as substrate respectively, blocking possible interferences by other enzymes, and allows the nonenzymatic reduction of nitro-blue tetrazolium by 5,10-methenyl tetrahydrofolate formed by the action of the cyclodehydrase on the substrate 5-formyl tetrahydrofolate, and by 10-formyl tetrahydrofolate formed by the action of cyclohydrolase on the substrate 5,10-methenyl tetrahydrofolate, thus revealing intracellular sites of enzyme activity. The methods appear to show only intracellular localization of the blue formazan deposits of reduced tetrazolium. The distribution of positivity in cells of human blood and bone marrow is described.

Aminohydrolases

[Epidemiology of acute leukemia of childhood in Greece (author's transl)].

A retrospective study of 151 aged less than 15 years children suffering from acute leukaemia is reported, the parameters studied were male: female ratio, type of leukemia, age and seasonal distribution of the illness. The disease started in spring in 53 children (35,1%), in summer in 34 (22,6%), in autumn in 36 (23,8%) and in winter in 28 (18,5%). The difference between spring and winter was statistically highly significant (X2 = 10,54, P less than 0,005). Sixty two children (41%) were 3-5 years old. The male female ratio was 1.75. The disease was of the acute lymphoblastic type in 88,1% of the cases.

Adolescent