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Radiation exposure due to radiological terrorism and military circumstances are a continuing threat for the civilian population. In an uncontrolled radiation event, it is likely that there will be other types of injury involved, including trauma. While radiation combined injury is recognized as an area of great significance, overall there is a paucity of information regarding the mechanisms underlying the interactions between irradiation and other forms of injury, or what countermeasures might be effective in ameliorating such changes. The objective of this study was to determine if difluoromethylornithine (DFMO) could reduce the adverse effects of single or combined injury if administered beginning 24 h after exposure. Eight-week-old C57BL/J6 young-adult male mice received whole-body cesium-137 ((137)Cs) irradiation with 4 Gy. Immediately after irradiation, unilateral traumatic brain injury was induced using a controlled cortical impact system. Forty-four days postirradiation, animals were tested for hippocampus-dependent cognitive performance in the Morris water maze. After cognitive testing, animals were euthanized and their brains snap frozen for immunohistochemical assessment of neuroinflammation (activated microglia) and neurogenesis in the hippocampal dentate gyrus. Our data show that single and combined injuries induced variable degrees of hippocampus-dependent cognitive dysfunction, and when given 24 h post trauma, DFMO treatment ameliorated those effects. Cellular changes including neurogenesis and numbers of activated microglia were generally not associated with the cognitive changes. Further analyses also revealed that DFMO increased hippocampal protein levels of the antioxidants thioredoxin 1 and peroxiredoxin 3 compared to vehicle treated animals. While the mechanisms responsible for the improvement in cognition after DFMO treatment are not yet clear, these results constitute a basis for further development of DFMO as a countermeasure for ameliorating the of risks for cognitive dysfunction in individuals subjected to trauma and radiation combined injury.

The interaction of cultured colon cancer cells with alpha-difluoromethylornithine (DFMO), an irreversible inhibitor of ornithine decarboxylase, has been investigated, using Raman micro-spectroscopy, in order to investigate DFMO induced effects. Raman spectra of the cultured HCT116 colon cancer cells treated with DFMO at different concentrations (0, 1, 2.5, 5, and 7.5 mM) were recorded in the range 550-2300 cm(-1). It has been shown that second derivative profile of the raw Raman spectrum of the colon cancer cells (i.e., the original experimental spectrum without any computational corrections) discriminates the weak but sharp bands from the strong, broad fluorescence background, and gives information about the position of the peaks and their band widths. The relative integrated intensities of the 781 cm(-1) and 788 cm(-1) DNA/RNA marker bands to that of 1451 cm(-1) band are found to decrease by addition of DFMO. Up to 65% reduction in the magnitude of the 1003 cm(-1) band, the characteristic phenylalanine ring breathing mode, in comparison 10 that of 1451 band, is observed. The results indicate DFMO induced apoptosis. On the other hand the intensity ratio of the tyrosine Fermi doubled around 830 cm(-1) and 850 cm(-1), which is a marker of hydrogen-bonding state of phenolic OH, is changed. The addition of DFMO may alter the tyrosine environment in cells, and parts of tyrosine residues are exposed. We also observed some modifications in amide I band, pointing out the alterations of the secondary structure of cell proteins by the presence of DFMO. (C) 2011 Elsevier B.V. All rights reserved.

To carry out a comparative study of inhibition of radiation carcinogenesis using alpha-difluoromethylornithine (DFMO), tinctures of ginseng, eleutherococcus and leuzea in female rats.Locally bred female LIO-strain rats were subjected to a single whole body γ-irradiation dose of 4 Gy at 12 weeks of age. Modifying drugs were given with drinking water from the 10th day after irradiation until the end of the experiment (for 16 months).Irradiated rats developed tumors 70.0-79.6% (malignant tumors: 43.7-45.0%) with a multiplicity of 1.48-1.75 (malignant: 0.5-0.58), while in unirradiated animals the incidence of all/malignant tumors was 21.9%/7.7% with multiplicity of 0.22/0.08. In exposed rats tumors most often developed in the mammary gland - 57.3%, reproductive and endocrine organs - 27.2%, and other localizations - 29.1%. All drugs, except leuzea, significantly reduced incidence and multiplicity of tumors, overall or at some localizations in irradiated rats. Highest, and practically equal inhibition, was shown by ginseng and DFMO, while eleutherococcus was clearly inferior. Ginseng reduced overall tumor incidence and multiplicity by 1.5 and 2.4 times, malignant tumor incidence and multiplicity - by 2.5 and 2.9 times, respectively.The ginseng extract is the most promising radiation carcinogenesis inhibitor tested.

We investigated whether in vitro L1210 growth inhibition by alpha-difluoromethylomithine (DFMO; 740 mu M) and 4-amidinoindan-l-one 2'-amidinohydrazone (CGP 48664A; 1.7 mu M) ii reversible with N-1-acetylspermine (N-1-acSp). Influences of N-1-acSp dose (1-100 mu M), time (0-12 h at 100 mu M), aminoguanidine (AG, 1 mM) and cell numbers (at 1 mu M N-1-acSp) on percentage S-phase, polyamine contents and viability were determined. DFMO/CGP 48664A decreased percentage S-phase from 58 to 26%, decreased spermidine (Sd) and sl,ermine (Sp) contents 3-fold, but did not affect viability. With increasing N-1-acSp dose, S-phase percentage and Sd contents increased concomitantly, reaching plateau values that were comparable with those of untreated controls. S-phase and Sd content increased from 4-6 h after N-1-acSp administration, reaching plateau values from 11 and 6 h, respectively. N-1-acSp content was dose dependent and increased linearly to reach plateau values from 8 h. AG did not affect any of these parameters. Addition of 1 mu M N-1-acSp to decreasing numbers of DFMO/CGP 48664A-treated cells caused increasing S-phase percentage, Sd and N-1-acSp contents. We conclude that cell cycle kinetics of cultured L1210 cells can be manipulated by the induction of growth inhibition with DFMO/CGP 48664A and its subsequent abolishment with N-1-acSp. N-1-acSp accumulation rate and its subsequent conversion to Sd is relatively slow compared with intracellular Sd needs. The data support the notion that Sd is the most important polyamine for growth. (C) 1998 Elsevier Science B.V. All rights reserved.

We investigated whether the in vivo growth inhibitory effect of the combination of 4-amidinoindan-l-one 2'-amidinohydrazone (CGP 48664A) and alpha-difluoromethylornithine (DFMO) is reversible by treatment with N-1-acetylspermine (N-1-acSp). DBA-2 mice were inoculated with 10(5) L1210 cells i.p. on day 0. From day 1 they received 2.50 mg CGP 48664A/kg i.p. once daily and 500 mg DFMO/kg i.p. twice daily. On day 5 they received 3 X 2500 nmol N-1-acSp i.p. with 15-min intervals. L1210 cell numbers, S-phase percentage and polyamine contents, and liver and spleen polyamine contents were monitored in the following 48 h. Four days treatment with CGP 48663A/DFMO reduced L1210 cell numbers, S-phase, and spermidine. N-1-acSp treatment increased L1210 spermidine from less than or equal to 8 h and percentage S-phase from 12 h. Maxima for spermidine and S-phase were reached at less than or equal to 8 and 18 h, respectively. These were below levels of untreated controls. Decreases were noted from 12 and 18 h, respectively. N-1-acSp was detectable in L1210 from 0-18 h. Liver spermidine was decreased by CGP 48664A/DFlVIO. After N-1-acSp treatment, liver N-1-acSp and N-1-acSd increased from less than or equal to 8 h, reached maxima at less than or equal to 8 and 10 h, respectively, and were undetectable from 15 h. We conclude that the in vivo growth inhibitory effect of CGP 48664A/DFMO is reversible by N-1-acSp treatment. The liver is probably involved in N-1-acSp terminal catabolism. The effect of the polyamine depletion-repletion scheme on S-phase cell numbers may be much more profound than present estimates from 5-bromo-2'-deoxyuridine incorporation. (C) 1998 Elsevier Science B.V. All rights reserved.

Objectives: Polyamines are organic polycations playing an essential role in cell proliferation and differentiation, as well as in cell contractility, migration and apoptosis. These processes are known to contribute to restenosis, a pathophysiological process often occurring in patients submitted to revascularization procedures. We aimed to test the effect of alpha-difluoromethylornithine (DFMO), an inhibitor of ornithine decarboxylase, on vascular cell pathophysiology in vitro and in a rat model of carotid arteriotomy-induced (re) stenosis. Methods: The effect of DFMO on primary rat smooth muscle cells (SMCs) and mouse microvascular bEnd. 3 endothelial cells (ECs) was evaluated through the analysis of DNA synthesis, polyamine concentration, cell viability, cell cycle phase distribution and by RT-PCR targeting cyclins and genes belonging to the polyamine pathway. The effect of DFMO was then evaluated in arteriotomy-injured rat carotids through the analysis of cell proliferation and apoptosis, RT-PCR and immunohistochemical analysis of differential gene expression. Results: DFMO showed a differential effect on SMCs and on ECs, with a marked, sustained anti-proliferative effect of DFMO at 3 and 8 days of treatment on SMCs and a less pronounced, late effect on bEnd. 3 ECs at 8 days of DFMO treatment. DFMO applied perivascularly in pluronic gel at arteriotomy site reduced subsequent cell proliferation and preserved smooth muscle differentiation without affecting the endothelial coverage. Lumen area in DFMO-treated carotids was 49% greater than in control arteries 4 weeks after injury. Conclusions: Our data support the key role of polyamines in restenosis and suggest a novel therapeutic approach for this pathophysiological process. (C) 2013 Elsevier Ireland Ltd. All rights reserved.

Background Mononuclear platinum anticancer agents hold a pivotal place in the treatment of many forms of cancers, however, there is a potential to improve response to evade resistance development and toxic side effects. BBR3464 is a promising trinuclear platinum anticancer agent, which is a polyamine mimic. The aim was to investigate the influence of polyamine pool reduction on the cytotoxic effects of the trinuclear platinum complex BBR3464 and cisplatin. Polyamine pool reduction was achieved by treating cells with either the polyamine biosynthesis inhibitor α-difluoromethylornithine (DFMO) or the polyamine analogue N1,N11-diethylnorspermine (DENSPM). Methods A human squamous cell carcinoma cell line, LU-HNSCC-4, established from a primary head and neck tumour was used to evaluate cellular effects of each drug alone or combinations thereof. High-performance liquid-chromatography was used to quantify intracellular polyamine contents. Inductively coupled mass spectroscopy was used to quantify intracellular platinum uptake. Cells were exposed to DFMO or DENSPM during 48 h at concentrations ranging from 0 to 5 mM or 0 to 10 μM, respectively. Thereafter, non-treated and treated cells were exposed to cisplatin or BBR3464 during 1 h at concentrations ranging from 0 to 100 μM. A 96-well assay was used to determine cytotoxicity after five days after treatment. Results The cytotoxic effect of BBR3464 on LU-HNSCC-4 cells was increased after cells were pre-treated with DENSPM or DFMO, and the interaction was found to be synergistic. In contrast, the interaction between cisplatin and DFMO or DENSPM was near-additive to antagonistic. The intracellular levels of the polyamines putrescine and spermidine were decreased after treatment with DFMO, and treatment with DENSPM resulted in an increase in putrescine level and concomitant decrease in spermidine and spermine levels. The uptake of BBR3464 was significantly increased after pre-treatment of the cells with DFMO, and varied dependent on the concentration of DENSPM. The uptake of cisplatin was unchanged. Conclusions Taken together, these results demonstrate that combinations of polyamine synthesis inhibitors with BBR3464 appear to be a promising approach to enhance the anticancer activity against HSCC.

Biochemical and pharmacologic studies suggest a role for the ornithine decarboxylase-polyamine system as a modulator of behavioral changes during vestibular compensation. alpha-Difluoromethylornithine specifically blocks the rate-limiting step of polyamine biosynthesis. To assess the effects of alpha-difluoromethylornithine on the acute phase of postural compensation, guinea pigs were divided into groups subjected to either unilateral labyrinthectomy only (n = 7), alpha-difluoromethylornithine (500 mg/kg/day) for 4 days before labyrinthectomy (n = 10), equivalent volumes of saline for 4 days before labyrinthectomy (n = 8), and sham operations (n = 5). Yaw head tilt and roll head tilt, trunk curvature, and air-righting reflex were measured at baseline and at regular intervals up to 4 weeks. alpha-Difluoromethylornithine significantly delayed recovery of normal air-righting but had no effect on yaw head tilt, roll head tilt, and trunk curvature. We also evaluated effects of alpha-difluoromethylornithine in compensated guinea pigs. Fully compensated animals from phase 1 were randomly assigned to receive alpha-difluoromethylornithine (500 mg/kg/day) or saline once daily for 4 days. Only 33% of alpha-difluoromethylornithine animals maintained air-righting, compared with 100% of saline-treated animals (p = 0.003). Maximum trunk curvature was greater in the alpha-difluoromethylornithine group (p = 0.02). Thus alpha-difluoromethylornithine not only delayed the time course for postural recovery after unilateral labyrinthectomy, it also transiently disrupted the maintenance of the compensated state.

Polyamines (PAs) are small aliphatic amines that play a major role in multicellular functions. The PA levels are controlled by ornithine decarboxylase (ODC), the rate limiting enzyme of PA biosynthesis. alpha-difluoromethylornithine (DFMO) is the ODC inhibitor, which has been shown to act as an antiproliferative agent in human cancer cells by irreversibly inhibiting ODC, which is overexpressed in breast cancer cells. Roscovitine (ROSC; CYC202), a selective cyclin-dependent kinase inhibitor, induces cell cycle arrest and concomitantly apoptosis in tumor cells. In this study, we aimed to investigate the possible role of PAs in ROSC-induced apoptosis in estrogen-dependent MCF-7 breast cancer cells. Cell viability was assessed following the exposure of MCF-7 cells to DFMO and/or ROSC by MTT cell viability assay. To evaluate the drug-induced apoptotic events, DNA fragmentation by Cell Death ELISA assay and 4,6-diamidino-2-phenylindole staining, were utilized. The disruption of mitochondrial membrane potential, caspase-9 and PARP cleavage was also determined in order to investigate the role of mitochondrial-mediated apoptosis. The modulation of Bcl-2 family members was also evaluated using the immunoblotting technique. Drug-induced reactive oxygen species was determined by a fluorometer following 2',7'-dichlorofluorescein diacetate staining. We found that ROSC induced apoptosis in a dose- and caspase-dependent manner. The ODC specific inhibitor, DFMO, altered the apoptotic effects of ROSC by increasing the generation of reactive oxygen species, decreasing the PA intracellular pool and modulating pro-apoptotic and anti-apoptotic Bcl-2 family members. All these findings suggest that ODC may be a critical target for evaluating the PA metabolic pathway as a therapeutic target in ROSC-induced mitochondrial-mediated apoptotis in estrogen-dependent MCF-7 breast cancer cells.

The three-dimensional structure of glycosomal glyceraldehyde-3-phosphate dehydrogenase [D-glyceraldehyde-3-phosphate:NAD+ oxidoreductase (phosphorylating), EC 1.12.1.12] from the sleeping-sickness parasite Trypanosoma brucei was solved by molecular replacement at 3.2-angstrom resolution with an x-ray data set collected by the Laue method. For data collection, three crystals were exposed to the polychromatic synchrotron x-ray beam for a total of 20.5 sec. The structure was solved by using the Bacillus stearothermophilus enzyme model [Skarzynski, T., Moody, P. C. E. & Wonacott, A. J. (1987) J. Mol. Biol. 193, 171-187] with a partial data set which was 37% complete. The crystals contain six subunits per asymmetric unit, which allowed us to overcome the absence of >60% of the reflections by 6-fold density averaging. After molecular dynamics refinement, the current molecular model has an R factor of 17.6%. Comparing the structure of the trypanosome enzyme with that of the homologous human muscle enzyme, which was determined at 2.4-angstrom resolution, reveals important structural differences in the NAD binding region. These are of great interest for the design of specific inhibitors of the parasite enzyme.

In this review an inventory is made of agents used to circumvent cis-diamminedichloroplatinum(II) (CDDP) resistance in vitro and in vivo. Agents that affect CDDP accumulation and membrane related systems, cytoplasmic defense mechanisms, as well as DNA accessibility and repair are reviewed. In resistant cell lines that have decreased accumulation, this can be restored by hyperthermic treatment. With or without effects on accumulation compounds that affect cell signal transduction often increase CDDP cytotoxicity. Calcium channel blockers and calmodulin inhibitors do not seem to be uniformly good modulators of CDDP resistance. For transduction modulators as well as cellular calcium affecting agents mechanisms are mainly unclear or controversial. Glutathione appears, with the now available agents, to be the most promising target for modulation of cytoplasmic defense mechanisms. At the nuclear level the inhibition of DNA repair related enzymes as well as the use of modified nucleosides to interfere with repair is studied in various cell lines. Results with these agents suggest opportunities for clinically feasible cytotoxicity modulation. DNA accessibility could in vitro be affected, but seems to be an unreliable target for modulation. Whenever possible the resistance mechanism affected and the mode of action of the modulator are discussed. As an alternative for modulation another method of overcoming CDDP resistance namely the application of CDDP analogues is considered.

The spleen is the largest lymphoid organ. The uptake of 14C-putrescine in spleen increased 5 to 8 days after inoculation of sarcoma-180 tumor cells. This phenomenon is in accord with the increase of spleen weight, and its uptake by teatment with DFMO increased about 2 times that of nontreatment with DFMO. A correlation between the spleen weight and 14C-putrescine uptake in spleen is obtained. By i.p. administration of lentinan; immunopotentiator, the uptake of 14C-putrescine in spleen was significantly increased. Putrescine would be useful for a splenic immunofunctional imaging agent.

We investigated whether the in vivo growth inhibitory effect of the combination of 4-amidinoindan-l-one 2'-amidinohydrazone (CGP 48664A) and alpha-difluoromethylornithine (DFMO) is reversible by treatment with N-1-acetylspermine (N-1-acSp). DBA-2 mice were inoculated with 10(5) L1210 cells i.p. on day 0. From day 1 they received 2.50 mg CGP 48664A/kg i.p. once daily and 500 mg DFMO/kg i.p. twice daily. On day 5 they received 3 X 2500 nmol N-1-acSp i.p. with 15-min intervals. L1210 cell numbers, S-phase percentage and polyamine contents, and liver and spleen polyamine contents were monitored in the following 48 h. Four days treatment with CGP 48663A/DFMO reduced L1210 cell numbers, S-phase, and spermidine. N-1-acSp treatment increased L1210 spermidine from less than or equal to 8 h and percentage S-phase from 12 h. Maxima for spermidine and S-phase were reached at less than or equal to 8 and 18 h, respectively. These were below levels of untreated controls. Decreases were noted from 12 and 18 h, respectively. N-1-acSp was detectable in L1210 from 0-18 h. Liver spermidine was decreased by CGP 48664A/DFlVIO. After N-1-acSp treatment, liver N-1-acSp and N-1-acSd increased from less than or equal to 8 h, reached maxima at less than or equal to 8 and 10 h, respectively, and were undetectable from 15 h. We conclude that the in vivo growth inhibitory effect of CGP 48664A/DFMO is reversible by N-1-acSp treatment. The liver is probably involved in N-1-acSp terminal catabolism. The effect of the polyamine depletion-repletion scheme on S-phase cell numbers may be much more profound than present estimates from 5-bromo-2'-deoxyuridine incorporation. (C) 1998 Elsevier Science B.V. All rights reserved.

We investigated whether in vitro L1210 growth inhibition by alpha-difluoromethylomithine (DFMO; 740 mu M) and 4-amidinoindan-l-one 2'-amidinohydrazone (CGP 48664A; 1.7 mu M) ii reversible with N-1-acetylspermine (N-1-acSp). Influences of N-1-acSp dose (1-100 mu M), time (0-12 h at 100 mu M), aminoguanidine (AG, 1 mM) and cell numbers (at 1 mu M N-1-acSp) on percentage S-phase, polyamine contents and viability were determined. DFMO/CGP 48664A decreased percentage S-phase from 58 to 26%, decreased spermidine (Sd) and sl,ermine (Sp) contents 3-fold, but did not affect viability. With increasing N-1-acSp dose, S-phase percentage and Sd contents increased concomitantly, reaching plateau values that were comparable with those of untreated controls. S-phase and Sd content increased from 4-6 h after N-1-acSp administration, reaching plateau values from 11 and 6 h, respectively. N-1-acSp content was dose dependent and increased linearly to reach plateau values from 8 h. AG did not affect any of these parameters. Addition of 1 mu M N-1-acSp to decreasing numbers of DFMO/CGP 48664A-treated cells caused increasing S-phase percentage, Sd and N-1-acSp contents. We conclude that cell cycle kinetics of cultured L1210 cells can be manipulated by the induction of growth inhibition with DFMO/CGP 48664A and its subsequent abolishment with N-1-acSp. N-1-acSp accumulation rate and its subsequent conversion to Sd is relatively slow compared with intracellular Sd needs. The data support the notion that Sd is the most important polyamine for growth. (C) 1998 Elsevier Science B.V. All rights reserved.

We studied the effect of polyamine depletion on growth and cell cycle characteristics of subcutaneously grown Lewis lung carcinoma (LLC) and fibrosarcoma (FIO 26) in mice. Polyamine depletion was achieved by inhibition of ornithine decarboxylase using 2-(difluoromethyl)ornithine, limitation of exogenous polyamines by administration of a polyamine-poor diet and decontamination of the gastrointestinal tract, and inhibition of endogenous polyamine reutilization by N,N'-bis-(2,3-butadienyl)putrescine (MDL 72527). Determination of S-phase cells was performed in tumor-cell suspensions by flow cytometry and in tumor tissue sections by microscopy, following in vivo labelling with 5-bromo-2'-deoxyuridine (BUdR). DNA synthesis rate was estimated from the incorporation of in vivo-injected [H-3]-thymidine (H-3-TdR). Both solid tumors almost completely stopped growing after access to polyamines was blocked. Growth inhibition was, however, not attended by changes in cell-cycle-phase distribution. Paradoxically, we measured increased in vivo H-3-TdR incorporation rates and unaltered BUdR-linked staining intensity in treated tumors. Injection of putrescine into treated LLC-bearing mice resulted in an increase in intracellular putrescine and spermidine concentrations, a slight increase in the number of S-phase cells and a marked drop in DNA synthesis rate within the following 9 hr.

The effect of alpha-difluoromethylornithine (DFMO) administered in drinking water (0.2 and 0.5%) against liver and intestinal coccidioses in experimentally infected rabbits was studied. Zootechnical and clinical parameters were used to assess the efficacy of the compound. In both coccidioses the lower dose did not show any important effect. The higher dosage (0.5%) however, reduced the lesions induced by coccidia to an important extent. The animals infected and treated with 0.5% DFMO showed similar weight gain, food intake and relative liver weight figures to the non-infected controls. Serum transaminase levels in the rabbits infected with Eimeria stiedai and treated with 0.5% DFMO were close to those of the non-infected animals. Infected rabbits treated with this dosage also showed reductions (over 80%) in faecal oocyst output.

The purpose of these studies was to examine metastatic potentials of a human colon tumor xenograft (T6) and three different human tumor cell lines (LS174T, HT29 and A549) using the intrasplenic-nude mouse model system (ISMS model system). A further objective was to study the activity of alpha-difluoromethyl-ornithine (DFMO) against primary and metastatic growth of the xenograft and the three cell lines. DFMO is an irreversible inhibitor of ornithine decarboxylase, a rate-limiting step in polyamine biosynthesis. Tumor burdens in the liver of nude mice were observed 6 weeks after the intrasplenic injection with LS174T and 12-14 weeks after intrasplenic injections with T6, HT29 and A549. Most of the mice developed primary tumor growth in the spleens. DFMO showed significant activity against liver metastases but had little or no activity against primary tumor growth in the spleens of the ISMS model and against s.c. growth of the xenograft. The studies demonstrated that the ISMS model system is an excellent system for studying metastatic behavior of human tumors and for studying the antimetastatic activity of experimental drugs.

We have determined the pharmacokinetic parameters for diffusion of alpha-[5-14C]-difluoromethylornithine (DFMO) from blood to brain, blood to cerebrospinal fluid (CSF), 9L rat brain tumor to adjacent brain, and blood to the subcutaneously-implanted 9L tumor in rats, and within the CSF of beagle dogs. DFMO diffusion across the blood-brain and blood-CSF barriers is quite restricted in both rats and dogs, but diffusion across the defective capillary system of both subcutaneous and intracerebral 9L tumors in rats is not. Under steady-state plasma conditions in rats, uptake of DFMO by the intracerebral 9L tumor and diffusion from tumor 5-6 mm into adjacent brain is not restricted; tissue/plasma ratios were approximately 1. Therapeutic efficacy will therefore not be limited by transport of DFMO into tumor or to the extracellular environment of tumor.

The pharmacokinetics of alpha-difluoromethylornithine (DFMO), an irreversible inhibitor of polyamine biosynthesis, were investigated in BALB/c (nude) mice after i.p. injection and after oral administration of radiolabeled drug. After i.p. injection the compound was rapidly cleared from the serum (t1/2 alpha = 14 min; t1/2 beta = 2.1 h) and from tissues such as muscle, liver and kidney (t1/2 alpha = 30-60 min; t1/2 beta = 2.1 h). DFMO concentrations were proportional to the administered dose (10-2000 mg/kg) in both serum and tissues. Oral administration of DFMO was carried out by dissolving the compound in drinking water at a concentration of 20 g/l. Studies on the distribution showed that DFMO did not accumulate preferentially in any particular tissue. An extremely wide variation in the dose actually achieved in different animals was observed; this ranged from 350 to 2800 mg/kg for a 14-h treatment period. A significant correlation (r = 0.83-0.92) between the dose of DFMO, calculated from the consumption of drinking water for each individual animal, and the DFMO concentrations in serum, muscle, spleen, liver and kidney was found. Similarly, it was shown that oral administration of DFMO during the daytime resulted in 10- to 15-fold lower levels than administration during the night. After discontinuation of treatment DFMO levels in serum and tissues decreased by 50% in approximately 6 h. From these results it is concluded that the optimal treatment schedule of mice with DFMO (or other drugs with similar pharmacodynamic properties) consists in a combination of oral administration via the drinking water and additional i.p. injection (during the daytime). Furthermore, the drug intake of the individual animals should be monitored to check whether the experimental requirements are actually fulfilled.

Zusammenfassung Der Einflus von alpha-Difluromethylornithin und Weinsteinsaure auf Spermatozoendichte, Sperma γGT, FSH, LH, Testosteron und Steroidausscheidung bei Patienten mit chronischer Prostatitis In der vorliegenden Studie wurde die Hemmung der Ornithindecarboxylase durch alpha-Difluoromethylornithin (Alpha-DFMO) bei Patienten mit chronisch nicht-eitriger Prostatitis untersucht. Nach Gabe von 18 g/24 Std. alpha-DFMO kam es zu einer partiellen klinischen Besserung sowie zur deutlichen Remission bei Patienten mit Hamatospermie. Die Bestimmung von gamma-Glutamyltransferase, LH, Testosteron im Sperma anderte sich deutlich in Abhangigkeit von der alpha-DFMO-Behandlung ebenso wie sich Spermamotilitat und Vitalitat als beeinflusbar erwiesen. Ein Abfall des Hamoglobins und Hamatokrits bei 2 von 10 Patienten um 16% normalisiert sich 2 Monate nach Absetzen der alpha-DFMO-Therapie. Unter der Behandlung mit Na-Tartrat zeigten sich ahnliche klinische Besserungen des Beschwerdebildes bei chronisch nicht-eitriger Prostatitis. Die Veranderungen der Spermazahl, der seminalen Gamma-GT, des LHs und des Testosterons scheint in Zusammenhang mit der bekannten Hemmung der Prostataphosphatase durch Tartrat zu stehen.

Excerpt To the editor: Alpha-difluoromethylornithine is an investigational antiprotozoal agent used to treatPneumocystis cariniipneumonia in patients with the acquired immunodeficiency syndrome (AI...