RESUMO
Melanosomes have been considered crucial targets in melanoma treatments. In this study we explored the role of melanosomes in photodynamic therapy (PDT), employing the synthetic Zn(II) phthalocyanine Pc13, a potent photosensitizer that promotes melanoma cell death after irradiation. Phototoxic action is mediated by reactive oxygen species increase. The internalization mechanism of Pc13 and its consequent subcellular localization were evaluated in melanotic B16-F0 cells. Pharmacological inhibitors of dynamin or caveolae, but not of clathrin, decreased Pc13 cellular uptake and phototoxicity. Similar results were obtained when cells over-expressed dominant negative mutants of dynamin-2 and caveolin-1, indicating that Pc13 is internalized by caveolae-mediated endocytosis. Confocal microscopy analysis revealed that Pc13 targets melanosomes and damage of these structures after irradiation was demonstrated by transmission electron microscopy. Treatment of pigmented B16-F0 and WM35 melanoma cells with the melanin synthesis inhibitor phenylthiourea for 48 h led to cell depigmentation and enhanced cell death after irradiation, whereas a 3-h period of inhibition did not modify melanin content but produced a marked reduction of Pc13 phototoxicity, together with a decrease of oxidative melanin synthesis intermediates. In contrast, the effect of Pc13 in amelanotic A375 cells was not altered by phenylthiourea treatment. These results provide evidence that melanosomes have a dual role in the efficacy of PDT. While melanin antagonizes the phototoxic action of Pc13, the release of cytotoxic synthetic intermediates to cytosol after irradiation and melanosome damage is conducive to the phototoxic response. Based on these findings, we demonstrate that melanosome-targeted PDT could be an effective approach for melanoma treatment.
Assuntos
Dermatite Fototóxica , Melanoma , Caveolina 1/metabolismo , Caveolina 1/farmacologia , Caveolina 1/uso terapêutico , Endocitose , Humanos , Indóis/química , Isoindóis , Melaninas/metabolismo , Melanoma/tratamento farmacológico , Melanoma/metabolismo , Melanossomas/metabolismo , Melanossomas/ultraestrutura , Feniltioureia/metabolismo , Feniltioureia/farmacologia , Feniltioureia/uso terapêuticoRESUMO
Trypanosoma brucei, the etiologic agent of sleeping sickness, is exposed to important changes in nutrients and temperature during its life cycle. To adapt to these changes, the fluidity of its membranes plays a crucial role. This fluidity, mediated by the fatty-acid composition, is regulated by enzymes named desaturases. We have previously shown that the oleoyl desaturase is essential for Trypanosoma cruzi and T. brucei. In this work, we present experimental support for the relevance of stearoyl-CoA desaturase (SCD) for T. brucei's survival, in both its insect or procyclic-form (PCF) and bloodstream-form (BSF) stages. We evaluated this essentiality in two different ways: by generating a SCD knocked-down parasite line using RNA interference, and by chemical inhibition of the enzyme with two compounds, Isoxyl and a thiastearate with the sulfur atom at position 10 (10-TS). The effective concentration for 50% growth inhibition (EC(50)) of PCF was 1.0 ± 0.2 µM for Isoxyl and 5 ± 2 µM for 10-TS, whereas BSF appeared more susceptible with EC(50) values 0.10 ± 0.03 µM (Isoxyl) and 1.0 ± 0.6 µM (10-TS). RNA interference showed to be deleterious for both stages of the parasite. In addition, T. brucei-infected mice were fed with Isoxyl, causing a reduction of the parasitemia and an increase of the rodents' survival.
Assuntos
Parasitemia/microbiologia , Estearoil-CoA Dessaturase/metabolismo , Trypanosoma brucei brucei/enzimologia , Tripanossomíase Africana/microbiologia , Animais , Feminino , Técnicas de Silenciamento de Genes , Camundongos , Parasitemia/tratamento farmacológico , Feniltioureia/análogos & derivados , Feniltioureia/uso terapêutico , Interferência de RNA , Estearoil-CoA Dessaturase/genética , Trypanosoma brucei brucei/efeitos dos fármacos , Trypanosoma brucei brucei/genética , Tripanossomíase Africana/tratamento farmacológicoRESUMO
The relationship of inhibitory quotient (IQ) with the virologic response to specific inhibitors of human hepatitis C virus (HCV) and the best method to correct for serum protein binding in calculating IQ have not been addressed. A common method is to determine a fold shift by comparing the EC(50) values determined in cell culture in the absence and presence of human serum (fold shift in EC(50) ), but this method has a number of disadvantages. In the present study, the fold shifts in drug concentrations between 100% human plasma (HP) and cell culture medium (CCM) were directly measured using a modified comparative equilibrium dialysis (CED) assay for three HCV protease inhibitors (PIs) and for a novel HCV inhibitor GS-9132. The fold shift values in drug concentration between the HP and CCM (CED ratio) were â¼1 for SCH-503034, VX-950 and GS-9132 and 13 for BILN-2061. These values were â¼3-10-fold lower than the fold shift values calculated from the EC(50) assay for all inhibitors except BILN-2061. Using the CED values, a consistent pharmacokinetic and pharmacodynamic relationship was observed for the four HCV inhibitors analysed. Specifically, an approximate 1 log(10) reduction in HCV RNA was achieved with an IQ close to 1, while 2-3 and greater log(10) reductions in HCV RNA were achieved with IQ values of 3-5 and greater, respectively. Thus, use of CED to define IQ provides a predictive and quantitative approach for the assessment of the in vivo potency of HCV PIs and GS-9132. This method provides a framework for the evaluation of other classes of drugs that are bound by serum proteins but require the presence of serum for in vitro evaluation.
Assuntos
Antivirais/farmacologia , Hepacivirus/efeitos dos fármacos , Hepatite C/tratamento farmacológico , Inibidores de Proteases/farmacologia , Carga Viral/efeitos dos fármacos , Antivirais/farmacocinética , Antivirais/uso terapêutico , Proteínas Sanguíneas/metabolismo , Carbamatos/farmacocinética , Carbamatos/farmacologia , Carbamatos/uso terapêutico , Linhagem Celular , Pesquisa Comparativa da Efetividade , Diálise/métodos , Hepacivirus/genética , Hepacivirus/patogenicidade , Hepatite C/virologia , Humanos , Concentração Inibidora 50 , Compostos Macrocíclicos/farmacocinética , Compostos Macrocíclicos/farmacologia , Compostos Macrocíclicos/uso terapêutico , Membranas Artificiais , Oligopeptídeos/farmacocinética , Oligopeptídeos/farmacologia , Oligopeptídeos/uso terapêutico , Feniltioureia/análogos & derivados , Feniltioureia/farmacocinética , Feniltioureia/farmacologia , Feniltioureia/uso terapêutico , Plasma/virologia , Prolina/análogos & derivados , Prolina/farmacocinética , Prolina/farmacologia , Prolina/uso terapêutico , Inibidores de Proteases/farmacocinética , Inibidores de Proteases/uso terapêutico , Ligação Proteica/efeitos dos fármacos , Quinolinas/farmacocinética , Quinolinas/farmacologia , Quinolinas/uso terapêutico , RNA Viral/sangue , Tiazóis/farmacocinética , Tiazóis/farmacologia , Tiazóis/uso terapêuticoRESUMO
In order to define the structural requirements of phenylthiourea (PTU), a series of thiourea and thiosemicarbazone analogs were prepared and evaluated as inhibitors of melanogenesis in melanoma B16 cells. The most potent analog was 2-(4-tert-butylbenzylidene)hydrazinecarbothioamide (1u) with an IC(50) value of 2.7 microM in inhibition of melanogenesis. The structure for potent inhibitory activity of these derivatives are required with the direct connection of pi-planar structure to thiourea without steric hinderance in PTU derivatives and the hydrophobic substituent at para position in case of semicarbazones.
Assuntos
Benzaldeídos/química , Melanoma Experimental/tratamento farmacológico , Peptídeos/química , Feniltioureia/química , Tiossemicarbazonas/química , Animais , Camundongos , Monofenol Mono-Oxigenase/antagonistas & inibidores , Monofenol Mono-Oxigenase/metabolismo , Peptídeos/síntese química , Peptídeos/uso terapêutico , Feniltioureia/síntese química , Feniltioureia/uso terapêutico , Relação Estrutura-Atividade , Tiossemicarbazonas/síntese química , Tiossemicarbazonas/uso terapêuticoRESUMO
UNLABELLED: Resistance mutations to hepatitis C virus (HCV) nonstructural protein 3 (NS3) protease inhibitors in <1% of the viral quasispecies may still allow >1000-fold viral load reductions upon treatment, consistent with their reported reduced replicative fitness in vitro. Recently, however, an R155K protease mutation was reported as the dominant quasispecies in a treatment-naïve individual, raising concerns about possible full drug resistance. To investigate the prevalence of dominant resistance mutations against specifically targeted antiviral therapy for HCV (STAT-C) in the population, we analyzed HCV genome sequences from 507 treatment-naïve patients infected with HCV genotype 1 from the United States, Germany, and Switzerland. Phylogenetic sequence analysis and viral load data were used to identify the possible spread of replication-competent, drug-resistant viral strains in the population and to infer the consequences of these mutations upon viral replication in vivo. Mutations described to confer resistance to the protease inhibitors Telaprevir, BILN2061, ITMN-191, SCH6 and Boceprevir; the NS5B polymerase inhibitor AG-021541; and to the NS4A antagonist ACH-806 were observed mostly as sporadic, unrelated cases, at frequencies between 0.3% and 2.8% in the population, including two patients with possible multidrug resistance. Collectively, however, 8.6% of the patients infected with genotype 1a and 1.4% of those infected with genotype 1b carried at least one dominant resistance mutation. Viral loads were high in the majority of these patients, suggesting that drug-resistant viral strains might achieve replication levels comparable to nonresistant viruses in vivo. CONCLUSION: Naturally occurring dominant STAT-C resistance mutations are common in treatment-naïve patients infected with HCV genotype 1. Their influence on treatment outcome should further be characterized to evaluate possible benefits of drug resistance testing for individual tailoring of drug combinations when treatment options are limited due to previous nonresponse to peginterferon and ribavirin.
Assuntos
Antivirais/uso terapêutico , Farmacorresistência Viral/genética , Hepacivirus/enzimologia , Hepatite C/tratamento farmacológico , Mutação/genética , Inibidores de Proteases/uso terapêutico , Antivirais/farmacologia , Carbamatos/farmacologia , Carbamatos/uso terapêutico , Estudos de Coortes , Feminino , Testes Genéticos , Hepacivirus/genética , Hepacivirus/patogenicidade , Hepatite C/sangue , Hepatite C/virologia , Humanos , Compostos Macrocíclicos/farmacologia , Compostos Macrocíclicos/uso terapêutico , Masculino , Oligopeptídeos/farmacologia , Oligopeptídeos/uso terapêutico , Feniltioureia/análogos & derivados , Feniltioureia/farmacologia , Feniltioureia/uso terapêutico , Filogenia , Prolina/análogos & derivados , Prolina/farmacologia , Prolina/uso terapêutico , Quinolinas/farmacologia , Quinolinas/uso terapêutico , Tiazóis/farmacologia , Tiazóis/uso terapêutico , Carga Viral , Proteínas não Estruturais Virais/antagonistas & inibidoresRESUMO
La sensibilidad gustativa a la feniltiocarbamida es un rasgo genético autosómico recesivo que afecta a todas las poblaciones del mundo, con una frecuencia que varía de acuerdo con la población estudiada. Este marcador genético es de gran utilidad en la caracterización de las poblaciones y como marcador asociado a algunas enfermedades. Su estudio en Cuba ha sido limitado y en la región central no se conoce la frecuencia de este carácter y su distribución poblacional. El objetivo de este trabajo es presentar los resultados obtenidos en una muestra de 750 individuos, en los cuales se estudió su respuesta a la sustancia química conocida como feniltiocarbamida o feniltiourea, así como su caracterización genética. Se encontró una frecuencia de individuos no sensibles a la feniltiocarbamida de 7,2 por ciento. No hubo diferencias significativas para los sexos y sí para los grupos raciales estudiados. El antimodo para los umbrales de gustación se situó en la solución número dos(AU)
Assuntos
Humanos , Marcadores Genéticos/genética , Limiar Gustativo , Feniltioureia/uso terapêuticoRESUMO
Relapse rates were studied in patients from northern Thailand who were started on dapsone monotherapy between 1949 and 1976. Included are a group of patients who, for various reasons, also received combinations of dapsone and thiambutosine, thiacetazone, isoniazid and streptomycin. The overall relapse rate in paucibacillary patients on dapsone monotherapy only was 2.7 per 1000 person-years at risk (PYR) (average observation period 13.9 years). In the multibacillary patients who received dapsone monotherapy only, the relapse rate was 10.5 per 1000 PYR (average observation period 12.4 years). In both groups it was found that 50% of the relapses occurred after the seventh year of follow up. The overall relapse rate in those patients whose treatment included thiambutosine, thiacetazone, isoniazid and/or streptomycin for at least 3 months was 17.9 per 1000 PYR (average observation period 11.9 years). The difference with the multibacillary patients treated with dapsone monotherapy only is not significant. It is concluded that alternative antileprosy drugs included in therapy regimens with dapsone in the pre-MDT era did not result in relapses occurring less often.
Assuntos
Dapsona/uso terapêutico , Hansenostáticos/uso terapêutico , Hanseníase/tratamento farmacológico , Quimioterapia Combinada , Feminino , Humanos , Isoniazida/uso terapêutico , Hanseníase/microbiologia , Masculino , Feniltioureia/análogos & derivados , Feniltioureia/uso terapêutico , Recidiva , Estudos Retrospectivos , Fatores Sexuais , Pele/microbiologia , Estreptomicina/uso terapêutico , Tioacetazona/uso terapêuticoRESUMO
The incidence of vitiligo varies from country to country. In the present study, seventy cases of vitiligo have been studied from skin out patient department of the Institute of Post-graduate Medicine & Research over a period of 2 years. The prevalence rate of vitiligo among the total out patient attendent was 0.4 per cent. 85 per cent of the cases belonged to the age group to 11-40 years. Male and female ratio was 2:1. Precipitating factors like physical injury, mental stress and strain had close link with development of skin lesion. In 11.4 per cent cases near relations were involved. Skin lesions according to the site showed lower extremity to be the maximally involved area and the genital areas were least involved.
Assuntos
Fármacos Dermatológicos/uso terapêutico , Feniltioureia/análogos & derivados , Feniltioureia/uso terapêutico , Vitiligo/epidemiologia , Adolescente , Adulto , Bangladesh , Criança , Pré-Escolar , Avaliação de Medicamentos , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Fotoquimioterapia , Vitiligo/tratamento farmacológicoRESUMO
Leprosy is a rare disease in Bulgaria. There have been 58 cases registered during the last one hundred years. The number of leprous patients in 1980 was 13, most of them came from the northern part of the country. The epidemiological studies indicate, that in some of the cases the infection has been acquired in other countries (South America, Romania, Jugoslavia, The Caucasian region), in most patients, however, the disease has been acquired in Bulgaria by an unknown source of infection. The most frequent clinical form is Lepra lepromatosa and the rarest Lepra indeterminata. All patients have been treated with 4,4-diaminodiphenyl sulphone (DDS), combined with Thiambutosine. The length of treatment depends upon the clinical type of leprosy. The results of the treatment are promising. Only two patient still reveal acid fast bacilli.
Assuntos
Hanseníase/epidemiologia , Adulto , Idoso , Bulgária , Dapsona/uso terapêutico , Feminino , Humanos , Hanseníase/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Feniltioureia/análogos & derivados , Feniltioureia/uso terapêuticoRESUMO
Drug trial with CIBA 1906 was conducted in 50 cases of lepromatous leprosy who were intolerant to dapsone therapy. Drug was tolerated well and lepra reactions were infrequent and mild. Clinical improvement was seen in 72% cases whereas no appreciable change was detected in 28% cases. An average reduction of 0.4 in BI was detected in 62% cases, while remaining cases did not show any reduction in BI. No significant side effects were encountered during the study. Antibacterial activity of CIBA 1906 was not found superior to dapsone.
Assuntos
Hanseníase/tratamento farmacológico , Feniltioureia/análogos & derivados , Feniltioureia/uso terapêutico , Adulto , Ensaios Clínicos como Assunto , Humanos , Hansenostáticos/uso terapêutico , Masculino , Feniltioureia/efeitos adversosRESUMO
Drug trial with CIBA 1906 was conducted in 50 cases of lepromatous leprosy who were intolerant to dapsone therapy. Drug was tolerated well and lepra reactions were infrequent and mild. Clinical improvement was seen in 72% cases whereas no appreciable change was detected in 28% cases. An average reduction of 0.4 in BI was detected in 62% cases, while remaining cases did not show any reduction in BI. No significant side effects were encountered during the study. Antibacterial activity of CIBA 1906 was not found superior to dapsone.
Assuntos
Masculino , Humanos , Adulto , Ensaios Clínicos como Assunto , Feniltioureia/análogos & derivados , Feniltioureia/efeitos adversos , Feniltioureia/uso terapêutico , Hansenostáticos/uso terapêutico , Hanseníase/tratamento farmacológicoRESUMO
The results of treatment of the group of leprosy patients at the lepromatous side of the leprosy spectrum registered at the Department of Dermatology of the University of Amsterdam in the years 1950-1976 were studied. The average duration of treatment to obtain bacteriologically negative skin biopsies in patients who were untreated at the time of registration, was 5 years. A substantial number of patients suffered a relapse; the main reasons for these relapses were discontinuation of treatment and DDS treatment in low dosage.
Assuntos
Hansenostáticos/uso terapêutico , Hanseníase/tratamento farmacológico , Ensaios Clínicos como Assunto , Clofazimina/uso terapêutico , Dapsona/uso terapêutico , Avaliação de Medicamentos , Humanos , Países Baixos , Feniltioureia/análogos & derivados , Feniltioureia/uso terapêutico , Recidiva , Rifampina/uso terapêutico , Fatores de TempoAssuntos
Hanseníase/tratamento farmacológico , Feniltioureia/análogos & derivados , Feniltioureia/uso terapêutico , Sulfametoxipiridazina/uso terapêutico , Tioacetazona/uso terapêutico , Animais , Quimioterapia Combinada , Camundongos , Feniltioureia/administração & dosagem , Sulfametoxipiridazina/administração & dosagem , Tioacetazona/administração & dosagemRESUMO
Over 100 patients with lepromatous leprosy were treated with rifampicin in a series of pilot, uncontrolled, and controlled trials in 1968-77. The rapid bactericidal effect of rifampicin on Mycobacterium leprae was confirmed. Clinical improvement became apparent sometimes as early as 14 days after the start of treatment. Nevertheless, a few persisting viable M leprae were detected as long as five years after the start of treatment with rifampicin either by itself or in combination with the bacteriostatic drug thiambutosine. Treatment with rifampicin and dapsone for six months reduced the number of persisting leprosy bacteria more than treatment with dapsone alone. Although rifampicin proved more effective than dapsone, it is unlikely that used by itself if can significantly shorten the length of treatment in lepromatous leprosy. Therefore initial intensive combined treatment with two or more bactericidal drugs (including rifampicin) warrants further investigation in both untreated leprosy and lepromatous leprosy resistant to dapsone.
Assuntos
Hanseníase/tratamento farmacológico , Rifampina/uso terapêutico , Animais , Ensaios Clínicos como Assunto , Dapsona/uso terapêutico , Combinação de Medicamentos , Humanos , Camundongos , Mycobacterium leprae/efeitos dos fármacos , Feniltioureia/análogos & derivados , Feniltioureia/uso terapêutico , Rifampina/administração & dosagem , Rifampina/farmacologiaRESUMO
Over 100 patients with lepromatous leprosy were treated with rifampicin in a series of pilot, uncontrolled, and controlled trials in 1968-77. The rapid bactericidal effect of rifampicin on Mycobacterium leprae was confirmed. Clinical improvement became apparent sometimes as early as 14 days after the start of treatment. Nevertheless, a few persisting viable M leprae were detected as long as five years after the start of treatment with rifampicin either by itself or in combination with the bacteriostatic drug thiambutosine. Treatment with rifampicin and dapsone for six months reduced the number of persisting leprosy bacteria more than treatment with dapsone alone. Although rifampicin proved more effective than dapsone, it is unlikely that used by itself if can significantly shorten the length of treatment in lepromatous leprosy. Therefore initial intensive combined treatment with two or more bactericidal drugs (including rifampicin) warrants further investigation in both untreated leprosy and lepromatous leprosy resistant to dapsone.
Assuntos
Humanos , Animais , Camundongos , Combinação de Medicamentos , Dapsona/uso terapêutico , Ensaios Clínicos como Assunto , Feniltioureia/análogos & derivados , Feniltioureia/uso terapêutico , Hanseníase/tratamento farmacológico , Mycobacterium leprae , Rifampina/administração & dosagem , Rifampina/farmacologia , Rifampina/uso terapêuticoAssuntos
Tuberculose Pulmonar/tratamento farmacológico , Tchecoslováquia , Etambutol/uso terapêutico , Humanos , Oxazóis/uso terapêutico , Feniltioureia/análogos & derivados , Feniltioureia/uso terapêutico , Protionamida/uso terapêutico , Rifampina/uso terapêutico , Tiossemicarbazonas/uso terapêuticoRESUMO
Productivity and tolerance trials were conducted with the anthelmintic thiophanate (Nemafax; May & Baker) in sheep in the United Kingdom. Tolerance studies, conducted in sheep of various types under several management systems, in which thiophanate was given orally at recommended dosage (50 to 100 mg/kg), or multiples thereof, in single or repeated doses showed that treatment was in all cases well tolerated. Thiophanate administered at 75 mg per kg or 250 mg per kg to groups of growing lambs with low faecal egg counts produced no post treatment depression of weight gain. When breeding ewes were treated with thiophanate at 150 mg per kg on days 14, 21 and 28 after introduction of rams to the flock, the anthelmintic produced no adverse effect on lambing performance. Trials to assess the beneficial effects of treatment were conducted in weaned lambs naturally infected with gastrointestinal nematodes. Groups of lambs were treated monthly with either thiophanate or tetramisole at recommended dosages. The two anthelmintics produced similar weight gains in the lambs and these were significantly better than those of untreated controls. In untreated controls faecal egg counts increased markedly and the clinical condition of these animals deteriorated.
Assuntos
Anti-Helmínticos/uso terapêutico , Carbamatos/uso terapêutico , Infecções por Nematoides/veterinária , Feniltioureia/análogos & derivados , Doenças dos Ovinos/tratamento farmacológico , Administração Oral , Animais , Carbamatos/administração & dosagem , Avaliação de Medicamentos , Infecções por Nematoides/tratamento farmacológico , Infecções por Nematoides/parasitologia , Feniltioureia/administração & dosagem , Feniltioureia/uso terapêutico , Ovinos , Doenças dos Ovinos/parasitologia , Tiabendazol/uso terapêuticoRESUMO
Thiophanate, administered at a dosage of 50 mg per kg to artifically infected pigs, removed 96 to 99 per cent of adult Oesophagostomum spp, Hyostrongylus rubidus and Trichuris suis. Activity was also high against larval stages of these nematodes, except for 26-day-old T suis. Thiophanate also showed ovicidal and larvicidal activity against H rubidus and Oesophagostomum spp. At 50 mg per kg thiophanate administered alone was inactive against Ascaris suum and Metastrongylus apri, the former species also being refractory at 200 mg per kg. Field trials confirmed these efficacy results in naturally infected animals. Pellet formulations providing mean dosages of 63 mg thiophanate per kg for adult pigs and 75 mg thiophanate per kg with 83 mg piperazine base per kg for growing pigs were highly effective in reducing the faecal output of Oesophagostomum spp, H rubidus and T suis eggs. In growing pigs, A suum was controlled by the thiophanate/piperazine product. No palatability or tolerance problems were observed when thiophanate or thiophanate/piperazine mixtures were administered at recommended dosage or multiples thereof in experimental or field studies.