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Biomedical subjects

A M Mauer

Publications and source records attributed to A M Mauer.

At least 109 records · Page 6Linked to original sources
PubMed1971

Synchronization and recruitment in acute leukemia.

The in vivo effects of several chemotherapeutic agents on the mitotic cycle of leukemic blasts in the bone marrow were evaluated by serial measurements of cells in mitosis and in deoxyribonucleic acid (DNA) synthesis as indicated by ability to incorporate tritiated thymidine or tritiated deoxyuridine. 28 studies were done in 23 children and 1 adult. The changes in the marrow after a single injection of L-asparaginase, hydrocortisone, cyclophosphamide, cytosine arabinoside, methotrexate, and an exchange transfusion (62% of the total blood volume) were evaluated. L-asparaginase and hydrocortisone were found to arrest the entry of cells into the S period. Cyclophosphamide appeared to inhibit DNA synthesis, arrest cells in mitosis, and inhibit the entry of cells into the S period. Cytosine arabinoside, and methotrexate inhibited DNA synthesis. During the period of time the cells were inhibited in the S phase by these two drugs, cells continued to enter the S period. Thus partial synchronization was achieved after these two drugs. An exchange transfusion had no consistent effect on the mitotic cycle, but partial synchronization in the S period was seen in one patient. To take advantage of the ability of cystosine arabinoside, to synchronize leukemic cells in the S phase, a second cycle-dependent drug was given at the time the leukemic blasts were synchronized. The second cycle-dependent drugs evaluated were vincristine, methotrexate, and cytosine arabinoside given by intravenous drip over a 12 hr period. Recruitment was found after cytosine arabinoside alone, and after prior synchronization with cytosine arabinoside and then the administration of either of these drugs. The results of these studies indicate that a greater therapeutic advantage can be achieved by a second cycle-dependent drug after synchronization than after the second drug alone.

Adult↗
PubMed1969

Drug effect in acute leukemia.

The in vivo therapeutic effect of vincristine, cytosine arabinoside, and corticosteroids on leukemic blast cells in the bone marrow was evaluated. 24 studies were done in 21 children with acute leukemia. 19 children had acute lymphoblastic leukemia, and two children had acute myeloblastic leukemia. Direct cytotoxicity or lysis of blast cells after drug administration was looked for by serial measurements of the volume of marrow buffy coat. Changes in proliferative capacity were evaluated by serial measurements of number of cells in mitosis and the per cent of cells in deoxyribonucleic acid (DNA) synthesis, as indicated by tritiated thymidine incorporation. Corticosteroid administration caused lysis of leukemic blast cells. Each drug affected the proliferative capacity of the leukemic cells by an action at a different part of the mitotic cycle. Corticosteroids suppressed the entry of cells into DNA synthesis. Vincristine arrested cells in mitosis. Cytosine arabinoside inhibited DNA synthesis. After the inhibitory effect of cytosine arabinoside, an increased number of cells began to synthesize DNA, a phenomenon indicating that partial synchronization of the mitotic cycle had been achieved in the leukemic cell population. The action of these drugs at different parts of the mitotic cycle might be important in designing treatment regimens where in two or more of these drugs are used.

Adolescent↗
PubMed1969

Reentry of nondividing leukemic cells into a proliferative phase in acute childhood leukemia.

Reentry of small leukemic blast cells into a proliferative phase was demonstrated in a 3 yr old girl with untreated acute lymphoblastic leukemia. Since the proliferating leukemic cell compartment in this disease is not self-maintaining, continual entry of cells into this compartment is necessary to prevent depletion of proliferating cells. In order to identify the source of replacement cells, the rate of change of tritiated thymidine-labeled cells in the proliferating compartment was observed by means of serial bone marrow samples under two conditions. In the first study period only 10% of small leukemic blast cells were labeled, and in the second study period 72% of this population had become lebeled. During the first period the proliferating blast cells were rapidly replaced by unlabeled cells, while during the second period the replacement cells were coming largely from a labeled cell source. The only identifiable source of cells for maintenance of the proliferating population which was virtually unlabeled during the first period and largely labeled during the second period was the population of small leukemic blast cells. The finding that the small blast cells are only temporarily nonproliferative could account for effectiveness of therapy directed primarily against a dividing cell population. Persistence of some cells with longer resting times into remission could provide a focus for subsequent relapse.

Bone Marrow↗