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A phase I study with recombinant human tumor necrosis factor α (rhuTNF-α; Knoll AG, Ludwigshafen, FRG) in patients with advanced malignant disease was undertaken to evaluate drug toxicity (organ specifity, time course, predictability, reversibility, maximal tolerated dose), effectiveness, antigenicity and pharmacokinetics. TNF was administered as a test dose followed by daily i.v. infusions for 5 days, every 3 weeks (single i.v. infusion lasting 10 min, TNF dissolved in 50 ml 5% human albumin). Dosage was increased in groups of 3 or 4 patients from 0.04 mg/m to 0.28 mg/m. A total of 19 patients with different cancers, including seven large-bowel carcinomas, three chronic myelogenous leukemias, three hypernephromas, two small-cell lung cancers, one malignant melanoma, one malignant lymphoma, one rhabdomyosarcoma and one fibrosarcoma were treated. Major side-effects were chills and fever (maximum 40.4°C, median 38.7°C, 19/19), headache (12/19), nausea and vomiting (12/19) and pronounced (>20%) hypotension (4/19). Acute side-effects could be diminished by paracetamol or indomethacin pretreatment, and with one possible exception no tachyphylaxis to TNF was noted. Mild renal toxicity was seen during TNF treatment. Pharmacokinetic studies showed a serum half-life ( t) ranging from 11 min to 17 min for doses from 0.04 mg/m to 0.16 mg/m and prolonged clearance with t ranging from 54 min to 70 min in the 0.20-0.28 mg/m dose range. No objective antitumor effects were observed in this phase I study. [ABSTRACT FROM AUTHOR]

Mice were exposed to single doses of whole body X-irradiation (1- 2 - 4 Gy) or were treated with sulphur mustard (15 mg/kg body weight i.p.). This treatment caused a reduction of the pluripotent stem cells in the bone marrow, of the total count of nucleated bone marrow cells in the femora and of the WBC in the peripheral blood. The size distribution of the bone marrow cells showed three separate peaks. From the histological examination of the bone marrow of X-irradiated mice it was deduced that the first peak represents erythrocytes, the second lymphocytes and the third peak the precursors of red and white blood cells. Multiple doses (25 - 50 - 100 mg/kg body weight) of azimexone, an immunomodulating substance, led after moderate doses of X-rays (2 Gy) or sulphur mustard to a more rapid recovery of the various parameters. In particular a stimulant action of azimexone on the pluripotent stem cells of mice not subjected to the injurious agents could also be demonstrated. [ABSTRACT FROM AUTHOR]

The d-ala- d activity in erythrocytes (RBC), femur bone marrow, liver and brain of mice was determined using a modification of the method of Berlin and Schaller (1974). In vitro incubation of lead acetate (PbAc) with these tissues resulted in a dose-dependent inhibition of the d-ala- d activity. The lead concentration which caused a 50% inhibition of the d-ala- d activity after 10 min incubation [ED-50] was 0.78 mg PbAc/femur bone marrow, 3.72 μg PbAc/ml RBC, 15.85 μg PbAc/g brain and 43.05 μg PbAc/g liver. An increase in the incubation time to 60 min reduced these ED-50 values between 44% for the erythrocytic enzyme and 67% for the brain enzyme. In vivo treatment of mice with oral lead administration (absorbed dose range: 1-100 μg PbAc/kg b.w.) for 1 or 3 months led to a dose-dependent and organ-specific inhibition of the d-ala- d activity. After 3 months of oral lead supply the maximum enzyme inhibition (54%) was found in the bone marrow. At the same time the lowest enzyme inhibition could be seen in the brain which retained 73% of its activity. The erythrocytic and liver enzyme activity was 71% and 72% resp. of the appropriate control. Within 3 weeks after completing the oral lead administration the brain enzyme activity was completely restored. The erythrocytic and liver enzyme activities were still significantly, but not very markedly inhibited, whereas the bone marrow d-ala- d remained seriously depressed. According to these experiments, the lead dose which causes a long term inhibiton of the bone marrow and erythrocytic d-ala- d activities is assumed to range between 50 and 100 μg PbAc/kg b.w. and day, as an absorbed dose. [ABSTRACT FROM AUTHOR]

The influence of lead on the number of nucleated bone marrow cells and pluripotent stem cells in femur bone marrow was investigated in mice. It was found that neither a single nor 10 days' oral administration of lead at doses of 10-1,000 μg PbAc/kg b.w. led to any change in the bone marrow cellularity. After 1 month's oral administration of 1,000 μg PbAc/kg b.w., on the other hand, there was a significant reduction of nucleated bone marrow cells and pluripotent stem cells in the femur bone marrow of up to 20% in comparison with controls. Within 14 days after completing the lead administration, however, normal values in the bone marrow cellularity were found again. Three months' oral administration of lead at doses of 100 and 1,000 μg PbAc/kg b.w. led to a significant reduction in nucleated bone marrow cells and pluripotent stem cells in the femur bone marrow of up to 28% compared with the controls. In contrast to the experiments with 1 month's oral administration of lead the regeneration of the bone marrow was not completed 14 days after completing the administration of the lead. These results show that lead at doses above 100 μg PbAc/kg b.w. causes on long-term administration a clear reduction of the nucleated bone marrow cells combined with a depressed regeneration ability of the pluripotent stem cells. [ABSTRACT FROM AUTHOR]

The half-life of the indian ink elimination (carbon clearance method) was used as a measure of the RES activity. A significant increase of the RES activity in mice was found already after a single intraperitoneal (i.p.) administration of 20, 50, or 100 μg PbAc/kg body weight (b.w.). A significant RES stimulation could also be demonstrated after a single or 10-day oral administration of lead at doses of 10-1,000 μg PbAc/kg b.w. No RES stimulation occurred, however, after 30-day oral administration of lead. On determining the reactivity of the RES to 1 μg endotoxin/kg b.w. it was found that it was already limited after a single and 10-day oral lead administration. After 30-day oral administration of lead (doses 10-1,000 μg PbAc/kg b.w.) the reactivity of the RES was completely suppressed. After a single and 10-day oral administration of lead (doses 10-1,000 μg PbAc/kg b.w.) we observed a marked leucocytosis. This effect was most clearly seen after a dose of 100 μg PbAc/kg b.w.; the leucocyte counts were increased by up to 50% in comparison with controls. After 30-day oral administration of lead, such a leucocytosis was no longer detectable. In accordance with the findings on the RES, the leucocytosis that is normally induced in the animals by 1 μg endotoxin/kg b.w. was significantly reduced or completely suppressed both after single and also after 10 and 30 days' oral administration of lead at doses of 100 and 1,000 μg PbAc/kg b.w. These results show that the resistance state of the mouse is impaired already by low doses of lead. [ABSTRACT FROM AUTHOR]

Lead levels in whole blood could be determined reliably up to a lower limit of 2 μg/100 ml blood, using a modified micromethod of the graphite tube furnace technique. Lead contents of various tissues were also determined by using the automated graphite tube furnace after wet ashing of the organs with nitric acid in autoclaves. Animal experiments with mice showed no measurable increase in blood lead level after a single, 10- or 30-days oral administration of lead in doses of 10-1000 μg lead acetate/kg body weight/day. However, these doses led to a rise in tissue lead content. There was a clear dependence of tissue lead content on type of organ examined, lead dose and duration of lead exposure. According to our experiments, the threshold dose which leads to a long-term increase in tissue lead content is assumed to be about 100 μg lead acetate/kg body weight/day, orally administered. [ABSTRACT FROM AUTHOR]

After a single intraperitoneal administration of lead in very small doses [1-100 μg Pbac/kg body weight (bw)], there was a dose-dependent, highly significant inhibition of erythrocyte D-aminolevulinic acid dehydratase (D-ALA-D) activity in mice. The maximal inhibition occurred between 3 and 24 h post injection (p.i.). After that, a rapid recovery of the D-ALA-D activity took place so that four days after lead administration, enzyme activity exceeded even the normal value. Only after eight days p.i. did the D-ALA-D value return to the initial level after a biphasic course. After 10 i.p. injections of 0.1 to 10 μg Pbac/kg bw, there was again a dose-dependent, highly significant inhibition of the erythrocyte D-ALA-D activity in mice. The maximal inhibition was shown to be 24 h after the last lead injection. In contrast to the single i.p. administration, however, we found a monophasic course for the return of D-ALA-D activity. The D-ALA-D values did not exceed the normal range at any time after 10 i.p. lead injections. Ten and 30 days oral administration of lead corresponding to i.p. doses exhibited similar results in D-ALA-D inhibition. [ABSTRACT FROM AUTHOR]

MTT staining procedures have been used in chemosensitivity testing of established cell lines of human and other sources as well as of human leukaemias, but only limited information on its application in primary solid human tumors is presently available. We have evaluated MTT staining in primary human Renal Cell Carcinomas (RCCs), studied various factors interfering with the optimal use, and finally applied it in subsequent chemosensitivity testing. The method depends on the conversion of a water-soluble tetrazolium salt (MTT) to a purple colored formazan precipitate, a reaction effected by enzymes active only in living cells. Single cell suspensions of RCCs were obtained either by enzymatic dispersion or by mechanical dissagregation, filtered through gauze, and purified by Ficoll density centrifugation. Tests were carried out in 96-well microculture plates. 10 viable tumor cells per well at 4 h incubation time with 20 μg MTT/100 μl total medium volume yielded best results. Formazan crystals were dissolved with DMSO, and the plates were immediately measured on a microculture plate reader at 540 nm. Under these criteria, linearity of the system could be demonstrated. For chemosensitivity testing, cells were continuously exposed to a number of drugs prior to the MTT staining procedure. Reproducibility of results was assessed and confirmed by culturing RCCs in flasks additionally, resubmitting them after 1, 2, and 4 weeks to the MTT assay. We conclude that the semiautomated MTT assay offers a valid, rapid, reliable and simple method to determine the degree of chemoresistance in primary human RCCs. [ABSTRACT FROM AUTHOR]