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Biomedical subjects

L Debusscher

Publications and source records attributed to L Debusscher.

At least 55 records · Page 3Linked to original sources

Scientific basis and criticism of current therapy of acute leukemia.

The factors which are thought to determine the response of acute leukemia (AL) to therapy are: 1) tumor size 2) drug dose 3) sensitivity to drug, 4) scheduling of drugs and 5) suppression of normal hemopoiesis. Each of these factors is considered in terms of the scientific data supporting their importance. Inability to measure the size of the tumor mass during all phases of treated AL continues to weaken rational strategies for therapy especially maintenance chemotherapy. Increasing the drug dose improves cell kill and potentially the cure rate up to the limits of toxicity. These limits may be extended by bone marrow transplantation. Various systems to study the drug sensitivity of leukemic cells are in experimental use, including stem cell assays but as yet they do not give a guide to altering therapy. The scheduling of multiple drugs is designed to increase cell kill by recruitment into the cycle, but "sanctuaries" appear to exist for resting cells. The suppression of normal hemopoiesis apparently due to leukemia-associated inhibitors is associated with favorable prognosis in childhood ALL but use of this information to improve treatment protocols is still unclear.

Acute Disease↗

Comparative randomized study of protected environment plus oral antibiotics versus oral antibiotics alone in neutropenic patients.

A series of 24 patients with severe neutropenia, most of whom had acute myeloblastic leukemia, were treated in an isolation unit with oral nonabsorbable antibiotics and were compared to 21 similar patients receiving oral antibiotics alone. The frequency of bacterial infections was lower in the patients receiving both isolation and oral antibiotics compared to the patients who received only oral antibiotics. The responses to chemotherapy in terms of remission rates were identical for the two groups.

Adolescent↗

Usefulness of cell kinetics for staging of chronic myeloid leukemia?

In the blood, the labelling index of the immature myeloid cells of one patient out of three decreased progressively from diagnosis to blastic crisis. This parameter deserves more investigation. In the marrow however, the 3H thymidine labelling indexes of the myeloid cells were not useful in predicting the blastic transformation of CML. The colony inhibiting activity of the PMN in CML neither was found to be useful in staging the disease.

Adult↗

Clonal origin of a T cell lymphoproliferative malignancy.

A woman with a T cell lymphoproliferative malignacy and heterozhgosity at the X chromosome-linked locus for glucose-6-phosphate dehydrogenase (G-6PD) isoenzymes was studied to find the clonal origin of her circulating neoplastic T cells. The red blood cells, polymorphonuclear cells, whole mononuclear cells, and T cell-depleted mononuclear cells contained both A and B isoenzymes of G-6-PD. In contrast, the tumor cells, separated by using their capacity to form rosettes with sheep red blood cells, contained only the B isoenzyme of G-6-PD. This observation strongly suggests the monoclonality of this T cell malignancy.

Adult↗

Cell kinetics in chronic lymphocytic leukaemia (CLL).

The fractional production rate of CLL lymphocytes, certainly in the peripheral blood and possibly in the lymph nodes, is often lower than normal. On the other hand, the absolute production in CLL blood and in lymph nodes seems to be considerably increased in most cases. Arguments for an increased lymphocyte life span in CLL, although fragmentary and dispersed, exist. The blood CLL lymphocytes, as normal lymphocytes, exchange rapidly with an extravascular pool of lymphocytes. However, recirculation of lymphocytes--from blood to blood via the lymph node and the thoracic duct--does not proceed normally in CLL. Whether this is related to the B nature of the CLL lymphocyte, to the leukaemic nature of the CLL lymphocyte or to mechanical factors--crowding of the extravascular pool--is still debatable.

Adrenal Cortex Hormones↗

Regulation of bone marrow myeloblast proliferation in chronic myeloid leukemia.

The in vivo [3H]thymidine-labeling index of bone marrow myeloblasts and myelocytes was determined for 9 hematologically normal individuals and 20 Ph-positive chronic myeloid leukemia (CML) patients in the chronic phase of their disease. The mean labeling index of myeloblasts from CML patients when the white blood cell (WNC) count was lower than 20,000/cu mm (42.4%) was not significantly different from that of normal myeloblasts (49.9). This index was found to be significantly (p less than 0.05) decreased to an average of 20.9% when the WBC count was higher than 40,000/cu mm. The mean labelling index of CML myelocytes was not significantly influenced by the level of WBC. The data presented indicate that such variations in the labeling index of the leukemic myeloblasts represent changes of their proliferative activity related to the level of WBC. It is concluded that the proliferation of CML myeloblasts is sensitive, to a certain degree at least, to the size of the myeloid cell population in the body or a subclass of it.

Bone Marrow↗

Empiric therapy for cancer patients: comparative study of ticarcillin-tobramycin, ticarcillin-cephalothin, and cephalothin-tobramycin.

Three combinations of antibiotics (cephalothin-tobramycin, cephalothin-ticarcillin, and ticarcillin-tobramycin) were administered empirically to 186 patients with cancer who were suspected of having a life-threatening infection. In approximately one-half of these patients, gram-negative infection was documented bacteriologically and consisted of septicemia in 50% of these patients. The three antimicrobial regimens were similarly effective and resulted in a favorable clinical response in approximately 55% of the patients. The administration of the cephalothin-tobramycin combination was associated with a significantly higher frequency of nephrotoxicity than that of the other two regimens.

Anti-Bacterial Agents↗

Hairy cell leukemia: functional, immunologic, kinetic, and ultrastructural characterization.

A diagnosis of hairy cell leukemia was made by optic microscopy, phase-contrast microscopy, electron microscopy, scanning microscopy, and histochemistry of the abnormal blood cells. In vivo these cells were found to have a half-time in the blood of approximately 150 hr. In vitro they had the capacity to adhere firmly to plastic, making it possible to obtain a pure population of hairy cells. Neither T-rosette formation nor phytohemagglutinin (PHA) transformation could be demonstrated in these cells. On the other hand, the presence of immunoglobulins on the surface of the hairy cells (HC) by immunofluorescence, and the synthesis and secretion by these cells of IgM type lambda-chains shown by radioimmunodiffusion, were in favor of their B-type lymphocyte origin. Similarities to chronic lymphocytic leukemia were apparent.

Bone Marrow↗