Werner E. Brandeis

EFFECTS OF METHOTREXATE ON RABBIT TESTES Part 1: Morphological Changes

Methotrexate (MTX) has the potential of eradicating small infiltrations of leukemic cells in the gonads. We examined the morphological changes in rabbit testes after a single dose (57.5 mg/kgBW) or repeated low doses (6 mg/kgBW once a week for 14 weeks) of MTX IV. Fertility rate and spermatogenic activity were evaluated using the tubular fertility index (TFI). Testicular MTX concentrations (measured by RIA) were in the same range in both groups. Only after repeated MTX application were reduction of TFI and signs of germinal cell line degeneration found. When given repetitively, MTX therapy may modify the fertility and tubular morphology. Long-term follow-up will show how these changes affect future fertility.

Veränderungen der Blut-Liquorschranke für Serumproteine bei Kindern mit akuter lymphatischer Leukämie

The blood-CSF barrier inhibits permeation of most chemotherapeutic agents into the central nervous system (CNS). The influence of systemic chemotherapy and prohylactic CNS irradiation on the permeability of the blood-CSF barrier was studied in 49 children treated for acute lymphoblastic leukemia (ALL) or non-Hodgkins lymphoma. To study the permeability of the blood-CSF barrier under treatment according to BFM-ALL protocols, nephelometric determinations of albumin, immunoglobulin G (IgG), and alpha-2-macroglobulin in serum and CSF and total protein in CSF were performed at several time intervals during chemotherapy and prophylactic cranial irradiation. During systemic induction chemotherapy, no significant changes of blood-CSF barrier could be observed. In contrast, in the course of prophylactic CNS irradiation and intrathecal methotrexate application, a significant elevation of albumin, alpha-2-macroglobulin and total protein in CSF, and a significant decrease of blood:CSF ratios for albumin and alpha-2-macroglobulin were observed. IgG did not change significantly. After prophylactic CNS treatment and during maintenance chemotherapy protein concentrations and blood:CSF ratios gradually returned to normal range. This normalization was accelerated by cortisone treatment during the reinduction period.SummaryThe blood-CSF barrier inhibits permeation of most chemotherapeutic agents into the central nervous system (CNS). The influence of systemic chemotherapy and prohylactic CNS irradiation on the permeability of the blood-CSF barrier was studied in 49 children treated for acute lymphoblastic leukemia (ALL) or non-Hodgkins lymphoma.To study the permeability of the blood-CSF barrier under treatment according to BFM-ALL protocols, nephelometric determinations of albumin, immunoglobulin G (IgG), and alpha-2-macroglobulin in serum and CSF and total protein in CSF were performed at several time intervals during chemotherapy and prophylactic cranial irradiation.During systemic induction chemotherapy, no significant changes of blood-CSF barrier could be observed. In contrast, in the course of prophylactic CNS irradiation and intrathecal methotrexate application, a significant elevation of albumin, alpha-2-macroglobulin and total protein in CSF, and a significant decrease of blood: CSF ratios for albumin and alpha-2-macroglobulin were observed. IgG did not change significantly.After prophylactic CNS treatment and during maintenance chemotherapy protein concentrations and blood:CSF ratios gradually returned to normal range. This normalization was accelerated by cortisone treatment during the reinduction period.

Effects of Methotrexate on Rabbit Testes Part 2: Hormonal Changes

Thirty mature and peripubertal male rabbits were examined for endocrine function and tissue methotrexate (MTX) concentration after single (57.5 mg/kgBW, group 1) and repeated (6 mg/kgBW, once a week for 14 weeks, group 2) MTX doses. Follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone, and androstenedione plasma levels were measured by radioimmunoassay (RIA). We found elevated plasma FSH levels in both groups. Elevated plasma androstenedione level and reduced plasma testosterone level in group 2 suggest an enzymatic defect in the gonadal steroid synthesis. Unchanged LH plasma level, when compared to controls, is thought to be the result of a combined effect of MTX on the gonadal steroids and gonadotropin synthesis.

Changes in the EEG background activity of children with acute lymphoblastic leukemia during cytotoxic therapy.

Thirteen children with acute lymphoblastic leukemia (ALL) were investigated before and during cytotoxic therapy. EEG findings were correlated with the clinical course and the therapy protocol and compared with normal data obtained from 295 healthy children. Frequency analysis of the background activity of the EEG revealed an initial slowing of the background activity prior to therapy and further slowing each time a combination of vincristine (VCR), daunorubicin (DAU) or adriblastine (ADR), prednisone (PRED), and L-asparaginase (L-ASP) was administered. The slowing of the background activity correlated only with the administration of these drugs. DAU, ADR, and PRED are not known to influence the EEG; therefore, VCR and L-ASP remain the primary candidates responsible for the central nervous system alteration.

Dihydrofolate reductase-activity in brain tissue

SummaryThe mechanism responsible for the toxic late effects of cranial irradiation, followed by the administration of systemic methotrexate (MTX) on brain tissue, is still under discussion. We studied the influence of X-irradiation on dihydrofolate reductase (E.C. 1.5.1.3) activity (DHFR), the enzyme inhibited by MTX. New Zealand white rabbits, 6–9 weeks old, underwent 24 Gy fractionated or 20 Gy single-dose brain irradiation using a 60Co source. Before, immediately following, and 1, 2, 4, 12 weeks after irradiation, DHFR was measured in brain and liver tissue by a photometric assay. DHFR in brain tissue was 11.9±2.9 mU/g wet weight (ww) × h and in liver tissue 121.8±24.2 mU/g ww × h. Fractionated brain irradiation with 2 Gy per day produced no significant changes in brain DHFR. Single-dose cranial irradiation significantly decreased brain DFHR (7.3±0.6 mU/g ww × h). Suppression of the developmental increase of DHFR by X-irradiation in young rabbits could be excluded by determining the unchanged brain-to-liver ratios of DHFR in the animals with fractionated brain irradiation.