The third-generation P-glycoprotein inhibitor tariquidar may overcome bacterial multidrug resistance by increasing intracellular drug concentration.

OBJECTIVES: The use of efflux pump inhibitors may be a powerful strategy to overcome transporter-mediated bacterial multidrug resistance. In the present study, we set out to investigate the potency of tariquidar, a third-generation P-glycoprotein inhibitor in clinical development, for overcoming bacterial resistance towards ciprofloxacin. METHODS: Staphylococcus aureus 29213 (SA29213) and S. aureus 1199B (SA1199B), which overexpresses the multidrug transporter NorA, as well as Pseudomonas aeruginosa 27853 and Stenotrophomonas maltophilia BAA-85, which expresses SmeDEF, were exposed to ciprofloxacin in the presence and absence of tariquidar or, for comparative reasons, elacridar. Activity of both P-glycoprotein inhibitors was evaluated by determination of MICs and time-kill curves, and by quantification of uptake of ciprofloxacin into bacterial cells. RESULTS: Activity of tariquidar and elacridar was comparable for S. aureus strains, and both dose-dependently increased susceptibility towards ciprofloxacin. Highest effects were observed for SA1199B, where the addition of tariquidar resulted in a 10-fold reduction of the ciprofloxacin MIC, while no effect was observed for P. aeruginosa. For S. maltophilia, elacridar but not tariquidar improved susceptibility. Uptake of [14C]ciprofloxacin and modification of susceptibility showed significant correlations (r=0.89, P<0.0001). Tariquidar had no intrinsic activity against any strain tested. CONCLUSIONS: We conclude that tariquidar has potent inhibitory effect against certain bacterial efflux pumps in vitro. Their high activity at clinically achievable concentrations might yield this class of drugs promising for future applications in infectious diseases.

No association of clock gene T3111C polymorphism and affective disorders.

CLOCK was hypothesised to be related to susceptibility of affective disorders. To test subsamples of affectively disordered patients, we examined age of onset (AoO), numbers of episodes and melancholic type of clinical manifestation. Using PCR and RFLP, we investigated in patients with unipolar depression and bipolar disorder (BP) whether the CLOCK T3111C SNP is associated with affective disorders (n=102) compared to healthy controls (n=103). No differences were found either in genotype or allele frequency distributions of T3111C polymorphism between patients compared to healthy controls (p>0.2). No deviations from Hardy-Weinberg Equilibrium (HWE) were detected either in patients, or healthy controls. Results suggest that there is no association between the T3111C SNP and affective disorders in general. Data of our sample replicate prior findings of Desan et al. [Am. J. Med. Genet. 12 (2000) 418]. Subsamples of patients with high numbers of affective episodes did show some deviations in genotypes (p=0.0585).

Antifungal drug response in an in vitro model of dermatophyte nail infection.

Despite terbinafine being fungicidal against Trichophyton rubrum in standard NCCLS assays and rapidly accumulating in nails in vivo, onychomycosis patients require prolonged terbinafine treatment to be cured. To investigate this, we developed a more clinically relevant onychomycosis in vitro test model. Human nail powder inoculated with T. rubrum and incubated in liquid RPMI 1640 salt medium, which did not support growth alone, developed extensive and invasive mycelial growth. Antifungal drugs were added at different concentrations and cultures incubated for 1 to 4 weeks. Fungal survival was determined by spreading cultures on PDA plates without drug and measuring CFU after 1 to 4 weeks incubation. Drug activity was expressed as the nail minimum fungicidal concentration (Nail-MFC) required for 99.9% elimination of viable fungus. Terbinafine Nail-MFC was 4 microg/ml after 1 week exposure, decreasing to 1 microg/ml after 4 weeks exposure, much higher than MFCs < or = 0.03 microg/ml determined in standard NCCLS MIC assays. In contrast, other clinically used drugs were unable to kill T. rubrum after 4 weeks incubation in this model. Invasive mycelial growth on nail appears to protect T. rubrum from the cidal action of systemic drugs, thus providing a rationale for the long treatment periods in onychomycosis.

In vitro susceptibility of Microsporum canis and other dermatophyte isolates from veterinary infections during therapy with terbinafine or griseofulvin.

We investigated the in vitro activity of terbinafine against fresh veterinary isolates of Microsporum canis and the potential of this organism to develop resistance in vivo during oral therapy. Dermatophyte cultures (n = 300) were obtained from naturally infected cats and dogs undergoing oral therapy with terbinafine or griseofulvin. M. canis comprised 92% of isolates; other species included Microsporum gypseum and Trichophyton mentagrophytes. Minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs) of terbinafine and griseofulvin were determined by broth macrodilution assay. Terbinafine was highly active against all three species with MIC90< or =0.03 microg ml(-1), in agreement with published data. However, terbinafine exhibited primary cidal activity against 66% of Microsporum isolates (n = 275) in contrast to the almost complete cidal effect in Trichophyton (n = 18). Griseofulvin was significantly less active than terbinafine (MIC90 = 4 microg ml(-1)) but had a primary cidal action on about 40% of the isolates. The data were analysed for changes in MIC and MFC during the course of therapy, which could be indicative for development of acquired resistance. Oral treatment of 37 animals with terbinafine for up to 39 weeks caused no increase in MIC or MFC of terbinafine, either in individual patients or in the whole group.

[Depressive pseudodementia]. / Depressive Pseudodemenzen.

Elderly depressive patients complaining about cognitive symptoms are at particular risk of being labelled as demented. It is well documented that depressive disorders frequently cause mild cognitive deficits which manifest in psychometric procedures. A wide spectrum of potentially reversible cognitive deficits related to a depressive syndrome are summarized under the term of "Depressive Pseudodementia (DPD)". Most depressive patients who are referred to "DPD" suffer from cognitive dysfunctions outside the range of dementia. The clinical interface between depression and dementia is complex. There is some evidence that depression may be a risk factor for the expression of Alzheimer's disease in later life and that depression may occur as a prodrome for Alzheimer dementia. Moreover, depression often complicates the course of dementing disorders. However, there is no evidence that depressive disorders cause dementia without coexisting depressive symptoms. It is essential to search for depressive symptoms even after cognitive symptoms have been found.

Synergistic interaction of terbinafine with triazoles or amphotericin B against Aspergillus species.

The in vitro activity of terbinafine alone and in combination with other antifungal agents was tested against isolates of Aspergillus fumigatus, A. flavus and A. niger. Testing was performed in a modified National Committee for Clinical Laboratory Standards (NCCLS) macrodilution broth assay, and interactions were examined using a checkerboard design. Terbinafine was highly active against Aspergillus isolates (minimum inhibitory concentration [MIC] 0.01 to 2 microg ml(-1)) with a primary fungicidal action (minimum fungicidal concentration [MFC] 0.02 to 4 microg ml(-1)). Amphotericin B was also highly active and cidal as expected (MIC 1 microg ml(-1), MFC 1 to 4 microg ml(-1)). The triazoles itraconazole and voriconazole were highly active but showed a variable degree of cidal activity against the different strains, voriconazole having the more potent cidal activity. Fluconazole had no significant activity (MIC > 128 microg ml(-1)). Drug combinations were tested in the A. fumigatus and A. niger strains. Terbinafine and amphotericin showed an additive to synergistic interaction depending on the isolate. Combinations of terbinafine with itraconazole or voriconazole displayed a potent synergistic interaction and fungicidal activity against all isolates. Surprisingly, fluconazole also potentiated the activity of terbinafine in an additive to synergistic fashion, despite its lack of activity alone. The results suggest potential clinical application of terbinafine in aspergillosis, either alone or in combination with amphotericin or triazoles.

In vitro activities of terbinafine against cutaneous isolates of Candida albicans and other pathogenic yeasts.

Terbinafine is active in vitro against a wide range of pathogenic fungi, including dermatophytes, molds, dimorphic fungi, and some yeasts, but earlier studies indicated that the drug had little activity against Candida albicans. In contrast, clinical studies have shown topical and oral terbinafine to be active in cutaneous candidiasis and Candida nail infections. In order to define the anti-Candida activity of terbinafine, we tested the drug against 350 fresh clinical isolates and additional strains by using a broth dilution assay standardized according to the guidelines of the National Committee for Clinical Laboratory Standards (NCCLS) M27-A assay. Terbinafine was found to have an MIC of 1 microg/ml for reference C. albicans strains. For 259 clinical isolates, the MIC at which 50% of the isolates are inhibited (MIC50) of terbinafine was 1 microg/ml (fluconazole, 0.5 microg/ml), and the MIC90 was 4 microg/ml (fluconazole, 1 microg/ml). Terbinafine was highly active against Candida parapsilosis (MIC90, 0.125 microg/ml) and showed potentially interesting activity against isolates of Candida dubliniensis, Candida guilliermondii, Candida humicola, and Candida lusitaniae. It was not active against the Candida glabrata, Candida krusei, and Candida tropicalis isolates in this assay. Cryptococcus laurentii and Cryptococcus neoformans were highly susceptible to terbinafine, with MICs of 0.06 to 0.25 microg/ml. The NCCLS macrodilution assay provides reproducible in vitro data for terbinafine against Candida and other yeasts. The MICs for C. albicans and C. parapsilosis are compatible with the known clinical efficacy of terbinafine in cutaneous infections, while the clinical relevance of its activities against the other species has yet to be determined.

Synthesis and structure-activity relationships of side-chain-substituted analogs of the allylamine antimycotic terbinafine lacking the central amino function.

Terbinafine is a therapeutically used inhibitor of fungal squalene epoxidase that has prompted extensive derivatization programs for structure-activity relationship studies. In the present study, derivatives of terbinafine were synthesized that lack the central tertiary amino group but have polar substitutents at the tert-butyl residue of the side chain. Evaluation of the antifungal potential revealed that representatives of this novel structural type can also exhibit broad antifungal activity, indicating that the central amino function of allylamine antimycotics is not essential for inhibition of fungal growth. Potency appears to correlate with the polarity of the introduced functional groups, while broad antifungal activity seems to be restricted to compounds with basic substituents. The dimethylamino-substituted "carba-analog" of terbinafine (8k) showed the best antimycotic profile within the whole series.

Synthesis and structure-activity relationships of the novel homopropargylamine antimycotics.

Analogues of the antimycotic allylamine terbinafine were prepared in which the naphthalene and the tert-butyl-acetylene moieties were preserved, but the spacer between these two groups was varied, and the antifungal activity of the new compounds was evaluated. All modifications of the original spacer such as reduction of the double bond, switching the position of the nitrogen atom, shortening, and elongation resulted in decreased potencies with one exception: Compounds with the CH2NMeCH2CH2 group between the 1-naphthalene and the optionally substituted tert-butyl-acetylene function demonstrated high antifungal activity in vitro. The new homopropargylamine derivatives are more potent than terbinafine against Aspergillus fumigatus. The results support the hypothesis that two lipophilic domains linked by a spacer of appropriate length and a polar center at a defined position in the spacer are the general requirements for high activity of allylamine antimycotics.

The efficacy of orally applied terbinafine, itraconazole and fluconazole in models of experimental trichophytoses.

The antimycotic efficacy of terbinafine, itraconazole and fluconazole was evaluated in guinea-pig trichophytoses (Trichophyton mentagrophytes, Trichophyton rubrum) by use of the hair root invasion test (HIT) and the auricular skin temperature test (STT). In the prophylactic HIT model using T. mentagrophytes as the infective agent, statistical evaluation of the ratios of protected/inoculated animals revealed ED50 values of 2.8 mg kg-1 for terbinafine, 10.7 mg kg-1 for itraconazole and 11.6 mg kg-1 for fluconazole. When T. rubrum was used in the same model the ED50 value of terbinafine was 7.3 mg kg-1 whereas only two of eight animals became protected by itraconazole and fluconazole at the highest dose of 16 mg kg-1. In the therapeutic HIT model carried out with T. mentagrophytes, the curative doses were increased for all test compounds, revealing an ED50 of 12.3 mg kg-1 for terbinafine and > 40 mg kg-1 for itraconazole and fluconazole. In the STT model, decline of temperature was quicker and more pronounced during therapy with terbinafine than during treatment with the triazole derivatives. Skin temperature was back to normal on day 8 (after seven treatments) with 20 mg kg-1 terbinafine, whereas a decline to, or almost to, physiological skin temperature was not observed until day 24 (5 days after the last treatment) in animals treated with 40 mg kg-1 itraconazole or fluconazole.

Synthesis and structure-activity relationships of naphthalene-substituted derivatives of the allylamine antimycotic terbinafine.

Derivatives of the allylamine antimycotic terbinafine (1) with varied substitution at the naphthalene ring system have been prepared, and their antifungal activity has been evaluated. In general, the potency is strongly dependent on the bulkiness of the substituent. Only hydrogen or in some cases fluorine are tolerated as substituents at positions 2-4 and 6-8 of the naphthalene moiety, whereas 5-substituents may be larger in size (F, Cl, Br, Me). Derivatives with fluorine at positions 3, 5, and 7 or chlorine at position 5 showed enhanced activity against yeasts relative to 1. This increase in sensitivity could be intensified by simultaneous introduction of two fluoro substituents at positions 5 and 7. Compound 7q demonstrated 8- to 16-fold improved potency against Aspergillus fumigatus, Candida albicans, and Candida parapsilosis.

Synthesis and structure-activity relationships of phenyl-substituted benzylamine antimycotics: a novel benzylbenzylamine antifungal agent for systemic treatment.

Derivatives of the benzylamine antimycotics with an extra phenyl ring incorporated in the side chain have been prepared and their antifungal activity evaluated. The potency is strongly dependent on the distance between the two phenyl groups and the type of spacer. Linking the aryl rings with a quaternary carbon atom resulted in the identification of highly active compounds 7f and 12a, having a novel 4-benzylbenzylamine side chain. Compound 7f and its 7-benzo[b]thienyl analogue 12a show significantly enhanced efficacy, in particular against Candida albicans, and are among the most potent allyl/benzylamine antimycotics identified so far. Extended investigations with the benzylbenzylamine derivative 7f revealed that, in addition to the enhanced antimycotic profile, the compound is the first representative of the benzylamine antimycotics suitable for systemic treatment.

Activation of an inducible c-FosER fusion protein causes loss of epithelial polarity and triggers epithelial-fibroblastoid cell conversion.

As a novel approach to studying the modulation of the polarized epithelial phenotype, we have expressed c-Fos and c-Myc estrogen receptor fusion proteins (c-FosER and c-MycER) in mammary epithelial cells. The hybrid proteins could be activated by estrogen for defined time periods and after the cells had achieved their fully polarized organization. Activation of c-MycER deregulated proliferation but did not affect epithelial polarity. Short-term activation of c-FosER induced the reversible loss of morphological and functional cell polarity. In contrast, long-term stimulation of c-FosER caused the cells to depolarize irreversibly, to invade collagen gels, and to undergo epithelial-fibroblastoid cell conversion. Our data suggest that Fos proteins are important in modulating the epithelial phenotype both in normal tissue development and in invasive processes.

Transcriptional repression of band 3 and CAII in v-erbA transformed erythroblasts accounts for an important part of the leukaemic phenotype.

The v-erbA oncogene confers two prominent properties on transformed erythroblasts: a block of spontaneous differentiation and tolerance to wide variations in the pH or ionic strength of culture medium. V-erbA acts as a constitutive repressor of erythrocyte-specific gene transcription, arresting the expression of at least three different erythroid genes: the erythrocyte anion transporter (band 3), carbonic anhydrase II (CAII) and delta-aminolevulinate synthase (ALA-S). To test whether or not the v-erbA induced repression of these genes is causally related to the v-erbA induced leukaemic phenotype, we have reintroduced the genes for band 3 or CAII into transformed erythroblasts via retrovirus vectors. We show here that such erythroblasts, expressing v-erbA, require the same narrow range of medium pH and ion concentration for growth as do transformed erythroblasts lacking v-erbA, i.e. the v-erbA induced tolerance to pH variation was abrogated. The v-erbA induced differentiation block, however, remained unaffected by the re-expression of band 3 and was only slightly affected by the re-expression of CAII. Our experiments show that the two v-erbA-related 'erythroblast transformation parameters' are separable: suppression of band 3 and CAII accounts for one parameter (pH/ion tolerance), while the second parameter (differentiation block) must involve v-erbA regulation of a different set of target genes.

The "hair root invasion test", a semi-quantitative method for experimental evaluation of antimycotics in guinea-pigs.

The hair root invasion test is a new method for preclinical evaluation of the antimycotic efficacy of chemical compounds in vivo based on their antifungal activity against dermatophytes located at hair roots in the depth of the hair follicles of guinea-pigs. The test design allows for semi-quantitative assessment of the invasion density of the hair follicles in mycotic foci of treated and untreated animals. Conditions that must be met in order to yield satisfactory results are discussed and test results from standard antimycotics are presented.

Mastomys natalensis as an experimental host for Brugia malaye subperiodic.

Infective larvae of Brugia malayi subperiodic obtained by dissection of infected Aedes togoi were injected subcutaneously into the scrotal region of Mastomys natalensis. From altogether 58 infected male M. natalensis 81% showed consistently or intermittently detectable microfilaraemia, whereas in 19% of the animals no microfilaraemia could be detected at any stage. The mean prepatent period was 136 days; the microfilarial density varied from 1 to 535 per 20 c. mm blood. In those animlas with consistently detectable and in general higher microfilaraemia an average of 13.1 live adult worms were found, against an average of 6.4 adult worms in animals with intermittent detectable and in general lower microfilaraemia. An average of 1.5 worms was found in animals which at no stage showed detectable microfilaraemia. A correlation between worm burden and prepatent period could be observed in the individual groups. From the total of 520 live adult worms recovered at necropsy, 37% were found in the lungs, 29% in the parenchyma of the testes and 34% in the lymphatic system. 47% of live fertile female worms were found in the lymphatic system, whereas the majority, i.e; 52% of infertile female worms were detected in the lungs. In addition, 380 encapsulated dead worms were found, most of them (98%) in the lymphatic system. 61% of a total of 900 live and dead worms were found in the region of the lymphatic system.