In vivo and in situ modulation of the expression of genes involved in metastasis and angiogenesis in a patient treated with topical imiquimod for melanoma skin metastases.

There is a growing body of evidence to support the efficacy of topical imiquimod in the treatment of primary skin carcinomas. Conflicting data exist concerning the use of imiquimod for the treatment of skin melanoma metastases. To date, only the impact of imiquimod on cytokines involved in immunological processes has been studied extensively. We report a woman successfully treated with imiquimod (once daily for 8 weeks) for skin melanoma metastases in whom we investigated the expression of molecules involved in metastasis and angiogenesis. Before and after treatment, a skin lesion was biopsied and the expression of the following molecules was investigated using real-time reverse transcription-polymerase chain reaction: matrix metalloproteinase (MMP)-1, 2 and 9 and their inhibitors KiSS-1 and tissue inhibitor of metalloproteinase (TIMP)-1, vascular endothelial growth factor (VEGF), fibroblast growth factor-2, and angiogenesis inhibitors (thrombospondin-1 and 2). Interferon (IFN)-alpha was also investigated as an in vivo marker of imiquimod activity. IFN-alpha was upregulated by the treatment. Under imiquimod, the following molecules were upregulated: TIMP-1, KiSS-1 and MMP-1. MMP-2 expression was not modified. MMP-9 expression was dramatically decreased. The expression of angiogenesis inhibitors was slightly increased but VEGF expression remained at a basal level. These results suggest that imiquimod could downregulate metastasis invasion and angiogenesis. However, these data were obtained at a transcriptional level and from a single case, and further investigations should include migration assays and additional cases in order to confirm that imiquimod may be safely used for treatment of melanoma metastases.

[Phase 2 clinical study of 123I-N-(2-diethylaminoethyl)-2-iodobenzamide in the diagnostic of primary and metastatic ocular melanoma]. / Etude clinique en phase 2 de la BZA2 (123IN-(2-diéthylaminoéthyl)-2-iodobenzamide) dans le diagnostic du mélanome malin oculaire et de ses métastases.

PURPOSE: Iodobenzamides are reported to possess an affinity for melanoma. A first selected compound, BZA, was studied in a phase 2 clinical trial on 159 patients as an imaging agent for the detection of primary melanoma and metastases with good results. We report the results of a second phase 2 clinical trial on 40 patients with a new radiopharmaceutical BZA2 (an orthoiodinated BZA analog), which was expected to provide quality images sooner after injection and with better imaging contrast. PATIENTS AND METHODS: Performance was evaluated in 40 patients classified with primary ocular lesions (12), suspicion of metastases of ocular or cutaneous origin (15), or with no known secondary lesion (13), and results were compared with conventional investigation techniques (ophthalmoscopy, ultrasonography, and angiography for ocular melanoma, whole-body CT scan and ultrasonography for metastases). RESULTS: No adverse events were recorded. The overall results on a per patient basis showed a sensitivity of 78% and a specificity of 95%. The four false negatives observed were ocular lesions (three with a thickness<3mm and one achromic), but all the proven secondary lesions were imaged. Moreover, negative BZA2 scintigraphy in cases of suspicious lesions led to the correction of two diagnoses: the prostatic origin of bone metastases and the endocrine tumor origin (APUD system) of an ocular lesion. DISCUSSION: BZA2 scintigraphy is an easy test with good tolerance. In the diagnosis of ocular primary melanoma, the sensitivity of the test is 64%, although limited by the thickness (3mm) and the pigmentation of the lesion. However, the BZA2 scintigraphy is a very useful test for the detection of melanoma metastases, with a sensitivity of 100% and a specificity of 95%. CONCLUSION: BZA2 scintigraphy showed good tolerance in patients and it appears promising for differential diagnosis, staging, and restaging of melanoma.

Melanin affinity of N-(2-diethylaminoethyl)-4-iodobenzamide, an effective melanoma imaging agent.

The cellular uptake and incorporation in macromolecules of iodine-125 labelled N-(2-diethylaminoethyl)-4-iodobenzamide ([125I]BZA), a melanoma imaging agent, was studied using human melanoma cells M3Dau (amelanotic) and M4Beu (melanotic). The interaction between [125I]BZA and synthetic melanin was examined in various conditions of incubation. The results showed that uptake was high only for M4Beu, whereas the incorporation in trichloroacetic acid-precipitable proteins was very low for both model cell lines, with no correlation with melanin content. Experiments with synthetic melanin showed that BZA binding to melanin was saturable and reversible, and involved several types of interaction. The influence of the ionic environment indicated that electrostatic forces play a role in the affinity, and the decrease in binding produced by the presence of an alcohol in the medium suggested that hydrophobic interactions may be involved in the binding mechanism. This was supported by the Scatchard analysis, which revealed two classes of binding sites, and the determination of two association constants (K1 = 3.9 +/- 1.9 x 106/M and K2 = 2.9 +/- 0.9 x 104/M). The affinity of BZA for melanin might explain the good results obtained in a phase II clinical trial for the diagnosis of malignant melanoma metastases, in which the specificity was 100%.

Synthesis, characterization and comparative biodistribution study of a new series of p-iodine-125 benzamides as potential melanoma imaging agents.

Iodobenzamides are reported to possess some affinity for melanoma. In order to identify the compound having the most appropriate pharmacokinetic properties as a potential melanoma imaging agent, thirteen new [125I]radioiodobenzamides with a butylene amide-amine spacer and various substituents on the terminal amino group were investigated. Their synthesis, radioiodination and biodistribution in B16 melanoma bearing C57BL6 mice are described and compared to [125I] labeled N-(2-diethylaminoethyl)-4-iodobenzamide ([125I]BZA), our reference compound. Changes in the terminal amino constituents induced modifications of lipophilicity, tumor uptake and organ distribution. The dimethylaminobutyl iodobenzamide appeared to be the most promising radiopharmaceutical imaging agent for the detection of melanoma and its metastases.

Distribution of I-BZA (N-2-diethylaminoethyl-4-iodobenzamide) in grafted melanoma and normal skin: a study by secondary ion mass spectroscopy.

Iodobenzamides labelled with radioactive iodine are undergoing clinical evaluation as imaging and potential therapeutic agents in malignant melanomas. However, the uptake mechanism in melanic tissues remains controversial. Using secondary ion mass spectrometry (SIMS), we studied the microscopic distribution of N-(2 diethylaminoethyl)-4 iodobenzamide (I-BZA) in B16 murine melanoma inoculated to C57BL/6J1 Co mice as well as in normal pigmented skin. SIMS provides specific detection of iodine-127 atoms entering 127I-BZA composition. In B16 melanoma, 127I-BZA distribution was found to be heterogeneous, with focal areas of high concentration corresponding to cells rich in melanin pigments. In skin, SIMS analysis showed 127I-BZA distribution appearing as multiple small selective concentration areas within the epidermis. The number of these foci decreased from the stratum basale towards the stratum corneum. In both tissues, the intracellular location appeared specifically intracytoplasmic, with no apparent nuclear uptake. Distribution of this molecule mirrored that of melanin pigments. There was no enhancement of uptake at the membrane site. These results suggest that, in melanic tumors as well as in normal pigmented tissue, specific uptake of 127I-BZA occurs in pigment cells, with a possible link to melanin pigments.

Joint scintigraphy in rabbits with 99mtc-N-[3-(triethylammonio)propyl]-15ane-N5, a new radiodiagnostic agent for articular cartilage imaging.

UNLABELLED: The aim of this study was to investigate joint scintigraphy in rabbits with 99mTc-N-[3-(triethylammonio)propyl]-15ane-N5 (NTP 15-5), a new radiopharmaceutical that specifically localizes in cartilaginous tissues. METHODS: Scans obtained after intravenous injection of the 99mTc-labeled compound in normal and arthropathy-induced rabbits were compared with those of the bone-imaging agent 99mTc-methylene diphosphonate (99mTc-MDP). RESULTS: The radioactive uptake of 99mTc-NTP 15-5 was detected in cartilaginous tissues 5 min after injection and was stable for 2 h. The uptake intensity was related to age and joint disease severity, and cartilage alterations not revealed by radiography induced a significant decrease of radiotracer uptake. On the other hand, imaging performed with 99mTc-MDP did not reveal the early changes in arthrosis but was more specific for bone remodeling in advanced stages of diseases or in inflammatory processes. CONCLUSION: Our results indicate that 99mTc-NTP 15-5 could be a good tracer for human arthrosic and arthritic cartilage detection, especially for the early diagnosis of joint diseases.

Effects of low-dose neutrons applied at reduced dose rate on human melanoma cells.

Human melanoma cells that are resistant to gamma rays were irradiated with 14 MeV neutrons given at low doses ranging from 5 cGy to 1.12 Gy at a very low dose rate of 0.8 mGy min(-1) or a moderate dose rate of 40 mGy min(-1). The biological effects of neutrons were studied by two different methods: a cell survival assay after a 14-day incubation and an analysis of chromosomal aberrations in metaphases collected 20 h after irradiation. Unusual features of the survival curve at very low dose rate were a marked increase in cell killing at 5 cGy followed by a plateau for survival from 10 to 32.5 cGy. The levels of induced chromosomal aberrations showed a similar increase for both dose rates at 7.5 cGy and the existence of a plateau at the very low dose rate from 15 to 30 cGy. The existence of a plateau suggests that a repair process after low-dose neutrons might be induced after a threshold dose of 5-7.5 cGy which compensates for induced damage from doses as high as 32.5 cGy. These findings may be of interest for understanding the relative biological effectiveness of neutrons and the effects of environmental low-dose irradiation.

A potential melanoma tracer: synthesis, radiolabeling, and biodistribution in mice of a new nitridotechnetium bis(aminothiol) derivative pharmacomodulated by a N-(diethylaminoethyl)benzamide.

Radioiodobenzamides are the best-known agents under study for the diagnosis of cutaneous melanoma and its metastases. We report the synthesis of a new BAT derivative radiopharmaceutical in which radioiodine is replaced by 99m-technetium. The cyclic intermediary methyl 4-[3-(4,4,7,7-tetramethyl-5,6-dithia-2, 9-diazacyclodecyl)-2-oxapropyl]benzoate (5) occurred in two different conformations identified by spectroscopic analysis. The final BAT ligand was radiolabeled using the nitridotechnetium core by a ligand-exchange reaction. Two different complexes were purified. After macroscopic 99-technetium synthesis, syn and anti isomers were identified. The global radiochemical yield was over 80%. The biodistribution of these two complexes was evaluated in mice bearing murine B16 melanoma. Extensive liver and kidney uptake was observed, but the benzamide tropism for the tumor was partially preserved.

Evaluation in mice of some iodinated melanoma imaging agents using cryosectioning and multi-wire proportional counting.

AMBIS 4000, a multi-wire proportional counter, was calibrated for iodine-125 measurements. The detector displayed a linear response over a wide dynamic range. Using whole-body mice cryosections, a linear relationship could be established between count rate per area (cpm/mm2) measured with the AMBIS 4000 detector and the count rate per gram (dpm/g) determined with an NaI(Tl) scintillation detector. A calibration curve could, thus be constructed. This new method allowed direct visual and quantitative evaluation of the biodistribution of a short series of 125I-labelled benzamides in melanoma-bearing mice. All the compounds studied showed good tumoral targeting ability. For one of them, ortho-N-(2-diethylaminoethyl)-4-iodobenzamide, liver and lung uptake decreased rapidly after dosing, making it a suitable tracer for scintigraphic detection of malignant melanoma.

A new quantitative method to evaluate the biodistribution of a radiolabelled tracer for melanoma using whole-body cryosectioning and a gaseous detector: comparison with conventional tissue combustion technology.

Whole-body autoradiography (WBA) and multi-wire proportional counting allow for spatial imaging of the radioactive material present in the tissues and organs of dehydrated animal sections. AMBIS 4000 counting of whole-body cryosections offers a sensitive, accurate and reproducible novel method for the quantitative measurement of the tissue distribution of a [14C] radiopharmaceutical. Intensity of AMBIS 4000 counting (net cpm/mm2) and concentration of radioactivity (nCi/g) were linearly related, yielding a standard curve. Evaluating biodistribution (a) provides pharmacokinetic data for predicting the potential tissue deposition of an absorbed dose of radioactivity in man, and (b) allows visual and quantitative evaluation of radioactivity in small anatomical structures that otherwise could not be detected by conventional tissue combustion technology. This new method of WBA, coupled with AMBIS 4000 counting, should prove a valuable method for pharmacodynamic studies, and afford a predictive tool for nuclear medicine by assessing specific targeting of selected tissues.

Clinical study of [123I] N-(2-diethylaminoethyl)-4-iodobenzamide in the diagnosis of primary and metastatic ocular melanoma.

PURPOSE: To assess the value of scintigraphy with [123I]N-(2-diethylaminoethyl)-4-iodobenzamide (BZA), a phase II clinical trial was performed on 48 patients with a suspicion of ocular melanoma. METHODS: 56 examinations were performed to image lesions with a clinical diagnosis of primary ocular melanoma before and/or after treatment, to observe the results in simulating lesions or to image metastases. RESULTS: Ocular BZA-scintigraphy demonstrated a sensitivity of 86%, and a specificity of 83%. Whole-body scintigraphy was used in the follow-up of treated patients and could be repeated. We imaged orbital recurrence, known and occult metastases, specially in the liver. After 9 conservative treatments ocular BZA-scintigraphy was negative in 9 eyes. CONCLUSION: The BZA-scintigraphy in combination with other diagnostic procedures appeared to be a suitable method in the diagnosis of ocular melanoma and a potentially useful imaging modality to screen for ocular malignant melanoma metastases.

Disposition and metabolism of a novel antineoplastic agent, 4-tert-butyl-[3-(2-chloroethyl)ureido]benzene, in mice.

1-Aryl-3-(2-chloroethyl)ureas are new agents that have shown promising cytotoxic and antineoplastic activities. In this work, we studied the disposition and metabolism of one of these molecules, 4-tert-butyl-[3-(2-chloroethyl)ureido]benzene (tBCEU). tBCEU was labeled with 14C and 13C in the urea function and in the chloroethyl moiety. After ip administration of the molecule labeled in the urea function, radioactivity was widely distributed in the whole organism, including the brain. HPLC analysis of plasma showed that tBCEU was extensively metabolized, with <20% being found in the plasma as unchanged tBCEU 1 hr after administration. One main metabolite was identified by NMR and MS analysis as N-[4-(2-hydroxy-1, 1-dimethylethyl)phenyl]urea, widely conjugated to glucuronic acid. The same metabolite was found in the urine. After administration of tBCEU labeled in the chloroethyl moiety, the same tissue affinities were observed, but the decrease of total radioactivity in blood and tissues was slower than that observed for the molecule labeled in the urea function. HPLC analysis of urine showed the presence of two main metabolites, identified by MS as thiodiacetic acid and its sulfoxide. From these results, we can deduce that the metabolic pathway of tBCEU involves N-dealkylation of the urea portion of the molecule and hydroxylation of the tert-butyl group. The strong cytochrome P450 reactivity of the carbon adjacent to the urea portion of tBCEU is probably related to particular sensitivity to oxidation at this position, based on the chemical structure of tBCEU. These results can explain the fact that the cytotoxic effect of tBCEU is not due to DNA alkylation, in contrast to that of its parent molecule, chloroethylnitrosourea.

Cultured neonatal rat cardiomyocytes and 99mTc-sestamibi to assess the direct effects of cardioplegia.

The efficacy of cardioplegia in neonatal myocardial protection is still a matter of debate. 99mTc-sestamibi cellular accumulation reflects sarcolemmal and mitochondrial electrical gradients. It was used to monitor the direct effects of two cardioplegic solutions, modified St Thomas' Hospital and Bretschneider, on normoxic and metabolically-inhibited cultured cells. Cellular accumulation of 99mTc-sestamibi, expressed by the ratio between intra and extra cellular concentrations, was assessed in three different sets of neonatal rat cardiomyocytes. Cells were either treated with different concentrations of modified St Thomas' solution (50, 75, 100%), they were treated or recovering from a treatment with modified St Thomas and Bretschneider solutions at 50% concentrations, or were recovering from treatment with modified St Thomas' and Bretschneider solution at 50% concentrations mixed with metabolic inhibitors. Cardioplegia depressed the tracer accumulation in a concentration-dependent manner. This effect was independent of the type of cardioplegia (120-min uptake, as a percentage of control values, modified St Thomas' 68+/-12 and Bretschneider 59+/-7) and was rapidly reversible. Cardioplegia was unable to prevent the depression of tracer accumulation induced by metabolic inhibitors and even induced a deleterious effect (120-min uptake, as a percentage of control values, metabolic inhibitors 69+/-12, metabolic inhibitors + modified St Thomas 38+/-14, metabolic inhibitors + Bretschneider 43+/-6) during recovery after 30 min of metabolic inhibition. It was concluded that cardioplegia has an apparent detrimental effect on neonatal cardiomyocytes accumulation of 99mTc-sestamibi during recovery from an ischaemic-like insult.

Validity of a model of cultured myocardial cells for assessment of cardioplegia.

Myocardial protection is usually studied in vitro on perfused heart preparations, but never directly on cultured cardiomyocytes. We evaluated a model of cultured newborn rat cardiomyocytes to study both the cytotoxicity and the protective effect against chemical hypoxia of three cardioplegic solutions (St Thomas' I, Bretschneider, St Thomas' II) under normothermic (37 degrees C) and hypothermic (4 degrees C) conditions. Cytotoxicity was evaluated in 50% and 100% concentrations of the cardioplegic solutions with incubation times from 90 to 360 min. Myocardial protection was studied in 50% cardioplegic solution with metabolic inhibitors. Immediate and late viabilities, after 24 h of recovery in the medium, were evaluated by simultaneous staining with fluorescein diacetate and propidium iodide. At 37 degrees C, the 50% concentration of the three cardioplegic solutions did not modify cell viability. At 37 degrees C, with 360 min of incubation, the 100% concentration of the St Thomas' I and Bretschneider solutions diminished immediate viability (mean +/- SD; medium 87% +/- 2%; St Thomas' I 58% +/- 5%; Bretschneider 37% +/- 8%; St Thomas' II 89% +/- 3%) as well as late viability (medium 69% +/- 2%; St Thomas' I 32% +/- 3%; Bretschneider 24% +/- 7%; St Thomas' II 65% +/- 4%). At 4 degrees C, immediate and late viabilities were unaffected by cardioplegic solutions. At 37 degrees C, after 360 min incubation time, metabolic inhibitors diminished immediate viability to 29% +/- 1% and late viability to zero. None of the three cardioplegic solutions used at 50% concentration prevented this effect. At 4 degrees C, immediate viability was not significantly affected by metabolic inhibitors (73% +/- 10%), but the use of Bretschneider cardioplegic solution seemed to be detrimental (53% +/- 9%). On the other hand, recovery phase after pretreatment with metabolic inhibitors with or without cardioplegic solutions for 360 min significantly diminished late viability (medium 63% +/- 7%; metabolic inhibitors 17% +/- 8%; St Thomas' I 17% +/- 6%; Bretschneider 8% +/- 6%; St Thomas' II 15% +/- 3%) and again cardioplegia was inefficient. In conclusion, in this in vitro model for the study of cardioplegic solutions, only pure concentrations of the St Thomas' I and Bretschneider solutions under normothermic conditions were cytotoxic. The well-known protective effects of hypothermia against ischemia and reperfusion injury were both reproduced. Therefore, and even though cardioplegia failed to have any protective effect, probably owing to a severe metabolic inhibition, this model may be useful for studying myocardial protection.

Comparable uptake of thallium-201 and technetium-99m MIBI in hibernating and "maimed" myocardium.

Thallium-201 and technetium-99m-MIBI uptake are comparable in "maimed" (i.e., partially viable) and hibernating myocardium. The appreciation of myocardial viability should be based not only on the presence of a regional contractility improvement, but also on the evaluation of the initial level of contractility and of tracer uptake in the concerned area.

O6-(alkyl/aralkyl)guanosine and 2'-deoxyguanosine derivatives: synthesis and ability to enhance chloroethylnitrosourea antitumor action.

A series of O6-(alkyl/aralkyl)guanosines and 2'-deoxyguanosine analogs extended to peracetyl and N2-acetyl derivatives, potentially water soluble, was synthesized. Each was associated with N'-(2-chloroethyl)-N-[2-(methylsulfonyl)ethyl]-N'-nitrosourea for in vitro evaluation on M4Beu melanoma cells of their ability to enhance the cytotoxic effect of this chloroethylnitrosourea, which is frequently reduced by repairs performed by O6-alkylguanine-DNA-alkyltransferase. Structure-activity analysis revealed that (i) benzyl and 4-halobenzyl are the O6-substituents required to afford a significant activity, (ii) 2'-deoxyguanosine derivatives demonstrate greater potency than guanosine analogs, (iii) acetylation, especially at the N2 position, generally results in compounds with moderate ability but may prevent incorporation of such nucleosides into DNA. Accordingly, O6-(4-iodobenzyl)-N2-acetylguanosine (3b) and O6-benzylperacetyl-2'-deoxyguanosine (2a), as well as O6-benzyl-N2-acetylguanosine (1b) and O6-benzyl-N2-acetyl-2'-deoxyguanosine (2b), by far the most water soluble, exhibit a good profile for further in vivo trials by the intravenous route.

Tissue distribution and metabolism in rat of an ethynesulphonamide with filaricidal activity.

1. The tissue distribution and metabolism of a new filaricidal agent P903 (N-[(2-phenylethynyl)sulfonyl]morpholine) were studied in rat. 2. After s.c. administration of 14C and 13C P903, the Tmax in the blood was observed on day 2. Elimination was slow and > 95% was bound to protein. Radioactivity was distributed in the whole organism but particularly in erythrocytes and the lymphatic channel. Four days later, > 60% of the radioactivity was excreted in urine and faeces at equal amounts and 15% remained at the injection point. 3. In all biological fluids tested no P903 was found but only its metabolites. 4. One principal metabolite, the N-[(2-phenyloxo-2-ethane) sulphonyl] morpholine or oxosulphonamide was identified in blood, urine and faeces as compared with the reference compound by GC/MS and NMR. This latter molecule was detected following hydrolysis by hydrochloric acid but not with beta glucuronidase/sulphatase. 5. Unconjugated and conjugated oxosulphonamide represented > 85% of the radioactivity at all times tested in blood but only 38 and 35% respectively of urinary and faecal radioactivity on day 1 after the administration of the labelled drug. 6. Thus, P903 is rapidly converted to a reactive metabolite, probably an oxirene, which is then conjugated with endogenous components to form conjugated oxosulphonamide and an unknown metabolite. The role of this reactive metabolite in antifilarial activity seems to be very important in understanding the mechanism of action of P903.

Disposition and metabolism of 2,6-dimethylbenzamide N-(5-methyl-3-isoxazolyl) (D2916) in male and female rats.

Disposition and metabolism of the new anticonvulsant 2,6-dimethylbenzamide N-(5-methyl-3-isoxazolyl) (D2916) was studied in male and female rats after oral administration of 14C-labeled material. D2916 was well absorbed in both sexes and distributed to all tissues, with maximal drug concentrations found in elimination and metabolization organs, as well as in fatty tissues. Striking differences in pharmacokinetic parameters of total radioactivity were observed between males and females; females had higher brain concentrations and longer blood and tissue half-lives. The study of blood, bile, urine, and brain metabolites showed that D2916 follows two degradation pathways related to hydroxylation of methyl groups. Males prefer to hydroxylate one of the methyl groups of the phenyl ring, and females prefer to hydroxylate the methyl of the isoxazolyl ring forming the active metabolite D3187. These findings suggest a sex difference in the location of the hydroxylation of the D2916 molecule and can explain the longer anticonvulsant effect observed in the female rat that is related both to an orientation of the metabolism toward the formation of the active metabolite and to a better ability to this metabolite to cross the blood-brain barrier, compared with the unchanged drug.

Enhancement by O6-benzyl-N2-acetylguanosine of N'-[2-chloroethyl]-N-[2-(methylsulphonyl)ethyl]-N'-nitrosourea therapeutic index on nude mice bearing resistant human melanoma.

The exposure of cells to O6-benzyl-N2-acetylguanosine (BNAG) and several guanine derivatives is known to reduce the activity of O6-alkylguanine-DNA alkyltransferase (MGMT) and to enhance the sensitivity of Mer+ (methyl enzyme repair positive) tumour cells to chloroethylnitrosoureas (CENUs) in vitro and in vivo. High water solubility and the pharmacokinetic properties of BNAG make it a candidate for simultaneous administration with CENUs by the i.v. route in human clinical use. In vivo we have shown previously that BNAG significantly increases the efficiency of N'-[2-chloroethyl]-N-[2-(methylsulphonyl)ethyl]-N'-nitrosourea (cystemustine) against M4Beu melanoma cells (Mer+) through its cytostatic activity by the i.p. route, but also increases its toxicity. To investigate the toxicity of BNAG and cystemustine when administered simultaneously in mice, we compared the maximum tolerated dose and LD50 doses of cystemustine alone or in combination with 40 mg kg(-1) BNAG by the i.p. route. The toxicity of cystemustine was enhanced by a factor of almost 1.44 when combined with BNAG. To compare the therapeutic index of cystemustine alone and the cystemustine/BNAG combination, pharmacological tests were carried out in nude mice bearing Mer+ M4Beu human melanoma cells. Isotoxic doses were calculated using the 1.44 ratio. The treatments were administered three times by the i.v. route on days 1, 5 and 9 after s.c. inoculation of tumour cells. Although the toxicities of the treatments were equal, BNAG strongly enhanced tumour growth inhibition. These results demonstrate the increase of the therapeutic index of cystemustine by BNAG and justify the use of BNAG to enhance nitrosourea efficiency in vivo by i.v. co-injection.

Application of textural features to the detection of ocular melanomas in scintigraphy.

A method for automated detection of ocular melanoma in scintigraphic images is described. The algorithm first performs an automatic segmentation of the eyes on specific reference images. The images of the eyes are then analyzed using textural parameters computed in several directions and averaged to damp directional information. Assuming that only one eye per patient will be pathological, the ratio of the textural parameters of the two eyes is computed. A statistical analysis is performed over these ratios to select the most highly discriminating textural parameters and detect the pathological patients. The method has been tested successfully on a population of 23 individuals and we found significant differences between pathological and normal patients.