The anticancer drug tamoxifen is active against Trypanosoma cruzi in vitro but ineffective in the treatment of the acute phase of Chagas disease in mice

The activity of the antineoplastic drug tamoxifen was evaluated against Trypanosoma cruzi. In vitro activity was determined against epimastigote, trypomastigote and amastigote forms of CL14, Y and Y benznidazole resistant T. cruzi strains. Regardless of the strain used, the drug was active against all life-cycle stages of the parasite with a half maximal effective concentration ranging from 0.7-17.9 µM. Two experimental models of acute Chagas disease were used to evaluate the in vivo efficacy of treatment with tamoxifen. No differences in parasitemia and mortality were observed between control mock-treated and tamoxifen-treated mice.

Quimioterapia da doença de Chagas: estado da arte e perspectivas no desenvolvimento de novos fármacos

Neglected diseases are a major global cause of illness, long-term disability and death. Chagas' disease is a parasitic infection widely distributed throughout Latin America, with devastating consequences in terms of human morbidity and mortality. The existing drug therapy suffers from a combination of drawbacks including poor efficacy, resistance and serious side effects. In 2009, we celebrate the 100th anniversary of the discovery of Chagas' disease, facing the challenges of developing new, safe and effective drugs for the treatment of this disease. This brief review attempts to highlight the state of the art, limitations and perspectives of Chagas' disease drug development.

Aversão alimentar adquirida e qualidade de vida em mulheres com neoplasia mamária

OBJETIVO: Avaliar o comportamento alimentar de mulheres com câncer de mama submetidas à quimioterapia, e sua relação com a qualidade de vida destas pacientes. MÉTODOS: A partir de um ensaio clínico do tipo antes e depois, selecionou-se 25 mulheres do Hospital AC Camargo (São Paulo, Brasil) durante o período de outubro de 2005 a abril de 2006. As pacientes inclusas no estudo apresentavam diagnóstico de câncer de mama, com estadiamento I e II e indicação de tratamento quimioterápico adjuvante. Nos momentos T0 (antes) e T1 (após o tratamento quimioterápico), o comportamento alimentar (consumo e aversão alimentar) foi avaliado por três recordatórios 24 horas e um questionário Food Action, respectivamente. A qualidade de vida foi monitorada por meio do questionário Functional Assessment of Cancer Therapy-Breast. RESULTADOS: Após o tratamento quimioterápico (T1), o consumo de macro e micronutrientes não apresentou alterações significantes, mas o consumo de frutas e sucos aumentou (p=0,03). Perfil inverso foi observado em relação à preferência por café preto (p=0,01) e pelo grupo de bebidas (p<0,001). Alimentos gordurosos (38%), laticínios (23%), café preto (15%), chá (15%), chocolate (7%) e carne vermelha (7%) foram os principais alimentos associados ao desconforto das pacientes. Análises de qualidade de vida mostraram que o tratamento quimioterápico promoveu significante redução no bem estar físico (p<0,01). Após o mesmo, algumas variáveis do comportamento alimentar foram significantemente correlacionadas com os parâmetros de qualidade de vida. CONCLUSÃO: A relação bilateral entre comportamento alimentar e qualidade de vida foi modificada negativamente pelo tratamento quimioterápico.

Prótese total articulada de joelho utilizada no tratamento de osteossarcoma apendicular em cão

O objetivo do trabalho foi reportar o planejamento cirúrgico, a técnica operatória, a instrumentação e os resultados da substituição completa do terço médio distal do fêmur, do platô tibial e da articulação do joelho por prótese em um cão acometido por osteossarcoma no fêmur esquerdo. A prótese foi confeccionada em aço, apresentando três componentes articulados, mantendo o movimento semelhante à articulação do joelho. As porções femorais e tibiais da prótese foram cimentadas aos respectivos ossos, após ostectomia do fêmur e do platô tibial. O animal foi submetido a seis sessões de quimioterapia, com doxorrubicina e carboplatina, intercaladas mensalmente, objetivando inibir o crescimento de possíveis metástases pulmonares. Durante os seis primeiros dias, o animal apresentou neuropraxia e impotência funcional do membro. Aos 10 dias, o cão iniciou leve apoio e aos 30 dias já utilizava o membro pélvico de forma mais efetiva, porém, o ângulo de extensão da articulação foi reduzido de 150° a 100° devido à contratura muscular e à fibrose na região da fossa poplítea. Após um ano de observação, não houve melhora do ângulo de extensão do joelho, porém, o animal fazia uso do membro com claudicação. Aos 425 dias de pós-operatório, o animal veio a óbito por insuficiência renal. Nesse tempo não ocorreram metástases pulmonares ou locais visíveis radiograficamente, mas o proprietário não permitiu a realização da necropsia do paciente, sendo impossível confirmar outros dados que pudessem esclarecer melhor a causa morte. Conclui-se que a substituição total do joelho de cão é uma cirurgia factível, que permite a preservação e a utilização do membro após ressecção da neoplasia, embora outras pesquisas devam ser conduzidas para obtenção de melhores resultados pós-cirúrgicos.

Prevalence and risk factors for aminoglycoside nephrotoxicity in intensive care units

In order to assess the prevalence of and risk factors for aminoglycoside-associated nephrotoxicity in intensive care units (ICUs), we evaluated 360 consecutive patients starting aminoglycoside therapy in an ICU. The patients had a baseline calculated glomerular filtration rate (cGFR) of ?30 ml/min/1.73 m2. Among these patients, 209 (58 per cent) developed aminoglycoside-associated nephrotoxicity (the acute kidney injury [AKI] group, which consisted of individuals with a decrease in cGFR of >20 per cent from the baseline cGFR), while 151 did not (non-AKI group). Both groups had similar baseline cGFRs. The AKI group developed a lower cGFR nadir (45 ± 27 versus 79 ± 39 ml/min/1.73 m2 for the non-AKI group; P < 0.001); was older (56 ± 18 years versus 52 ± 19 years for the non-AKI group; P = 0.033); had a higher prevalence of diabetes (19.6 per cent versus 9.3 per cent for the non-AKI group; P = 0.007); was more frequently treated with other nephrotoxic drugs (51 per cent versus 38 per cent for the non-AKI group; P = 0.024); used iodinated contrast more frequently (18 per cent versus 8 per cent for the non-AKI group; P = 0.0054); and showed a higher prevalence of hypotension (63 per cent versus 44 per cent for the non-AKI group; P = 0.0003), shock (56 per cent versus 31 per cent for the non-AKI group; P < 0.0001), and jaundice (19 per cent versus 8 per cent for the non-AKI group; P = 0.0036). The mortality rate was 44.5 per cent for the AKI group and 29.1 per cent for the non-AKI group (P = 0.0031). A logistic regression model identified as significant (P < 0.05) the following independent factors that affected aminoglycoside-associated nephrotoxicity: a baseline cGFR of <60 ml/min/1.73 m2 (odds ratio [OR], 0.42), diabetes (OR, 2.13), treatment with other nephrotoxins (OR, 1.61) or iodinated contrast (OR, 2.13), and hypotension (OR, 1.83). (To continue) In conclusion, AKI was frequent among ICU patients receiving an aminoglycoside, and it was associated with a high rate of mortality. The presence of diabetes or hypotension and the use of other nephrotoxic drugs and iodinated contrast were independent risk factors for the development of aminoglycoside-associated nephrotoxicity

Synthesis and total H-1- and C-13-NMR assignment of cephem derivatives for use in ADEPT approaches

We report the synthesis and total NMR characterization of 5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid-3-[[[(4''-nitrophenoxy)carbonyl]oxy]-methyl]-8-oxo-7[(2-thienyloxoacetyl)amino]-diphenylmethyl ester-5-dioxide (5), a new cephalosporin derivative. This compound can be used as the carrier of a wide range of drugs containing an amino group. The preparation of the intermediate product, 5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid-3-[methyl-4-(6-methoxyquinolin-8-ylamino) pentylcarbamate]-8-oxo-7-[(2-thienyloxoacetyl)amino]-diphenylmethyl ester-5-dioxide (6), as well as the synthesis of the antimalarial primaquine prodrug 5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid-3-[methyl-4-(6-methoxyquinolin-8-ylamino) pentylcarbamate]-8-oxo-7-[(2-thienyloxoacetyl)amino]-5-dioxide (7) are also described, together with their total H-1- and C-13-NMR assignments.

A Novel Organotellurium Compound (RT-01) as a New Antileishmanial Agent

Leishmaniasis is a neglected disease and endemic in developing countries. A lack of adequate and definitive chemotherapeutic agents to fight against this infection has led to the investigation of numerous compounds. The aim of this study was to investigate the effect of RT-01, an organotellurane compound presenting biological activities, in 2 experimental systems against Leishmania amazonensis. The in vitro system consisted of promastigotes and amastigotes forms of the parasite, and the in vivo system consisted of L. amazonensis infected BALB/c mice, an extremely susceptible mouse strain. The compound proved to be toxic against promastigotes and amastigotes. The study also showed that treatment with RT-01 produces an effect similar to that treatment with the reference antimonial drug, Glucantime, in L. amazonensis infected mice. The best results were obtained following RT-01 intralesional administration (720 mu g/kg/day); mice showed significant delay in the development of cutaneous lesions and decreased numbers of parasites obtained from the lesions. Significant differences in tissue pathology consisted mainly of no expressive accumulation of inflammatory cells and well-preserved structures in the skin tissue of RT-01-treated mice compared with expressive infiltration of infected cells replacing the skin tissue in lesions of untreated mice. These findings highlight the fact that the apparent potency of organotellurane compounds, together with their relatively simple structure, may represent a new avenue for the development of novel drugs to combat parasitic diseases.

The development of an immobilized enzyme reactor containing glyceraldehyde-3-phosphate dehydrogenase from Trypanosoma cruzi: the effect of species' specific differences on the immobilization

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) plays an important role in the life cycle of the Trypanosoma cruzi, and an immobilized enzyme reactor (IMER) has been developed for use in the on-line screening for GAPDH inhibitors. An IMER containing human GAPDH has been previously reported; however, these conditions produced a T. cruzi GAPDH-IMER with poor activity and stability. The factors affecting the stability of the human and T. cruzi GAPDHs in the immobilization process and the influence of pH and buffer type on the stability and activity of the IMERs have been investigated. The resulting T. cruzi GAPDH-IMER was coupled to an analytical octyl column, which was used to achieve chromatographic separation of NAD+ from NADH. The production of NADH stimulated by D-glyceraldehyde-3-phosphate was used to investigate the activity and kinetic parameters of the immobilized T. cruzi GAPDH. The Michaelis-Menten constant (K-m) values determined for D-glyceraldehyde-3-phosphate and NAD(+) were K-m = 0.5 +/- 0.05 mM and 0.648 +/- 0.08 mM, respectively, which were consistent with the values obtained using the non-immobilized enzyme.

LED Phototherapy to Prevent Mucositis: A Case Report

Objective: The purpose of this case report was to evaluate the efficacy of phototherapy using light-emitting diodes (LEDs) to prevent oral mucositis in a Hodgkin's disease patient treated with the ABVD ( doxorubicin [Adriamycin], bleomycin, vinblastine, and dacarbazine) chemotherapy regimen. Background Data: Mucositis is a common dose-limiting complication of cancer treatment, and if severe it can lead to alterations in treatment planning or suspension of cancer therapy, with serious consequences for tumor response and survival. Therefore, low-power lasers and more recently LEDs, have been used for oral mucositis prevention and management, with good results. Materials and Methods: In this study, a 34-year-old man received intraoral irradiation with an infrared LED array (880 nm, 3.6 J/cm(2), 74 mW) for five consecutive days, starting on chemotherapy day 1. In each chemotherapy cycle, he received the ABVD protocol on days 1 and 15, and received LED treatment for 5 d during each cycle. To analyze the results, the World Health Organization (WHO) scale was used to grade his mucositis, and a visual analogue scale (VAS) was used for pain evaluation, on days 1, 3, 7, 10, and 13 post-chemotherapy. Results: The results showed that the patient did not develop oral mucositis during the five chemotherapy cycles, and he had no pain symptoms. Conclusion: LED therapy was a safe and effective method for preventing oral mucositis in this case report. However, further randomized studies with more patients are needed to prove the efficacy of this method.

Severity of Oral Mucositis in Patients Undergoing Hematopoietic Cell Transplantation and an Oral Laser Phototherapy Protocol: A Survey of 30 Patients

Background Data and Objective: Oral mucositis (OM) is one of the worst cytotoxic effects of chemotherapy and radiotherapy in patients undergoing hematopoietic cell transplantation (HCT), and it causes severe morbidity. Laser phototherapy has been considered as an alternative therapy for prevention and treatment of OM. The aim of this study was to describe the incidence and severity of OM in HCT patients subjected to laser phototherapy, and to discuss its effect on the oral mucosa. Patients and Methods: Information concerning patient age and gender, type of basic disease, conditioning regimen, type of transplant, absence or presence of pain related to the oral cavity, OM grade, and adverse reactions or unusual events were collected from 30 patients undergoing HCT (allogeneic or autologous). These patients were given oral laser phototherapy with a InGaAIP laser (660 nm and 40 mW) daily. The data were tabulated and their frequency expressed as percentages. Results: In the analysis of those with OM, it was observed that 33.4% exhibited grade I, 40% grade II, 23.3% grade III, and 3.3% grade IV disease. On the most critical post-HCT days (D+5 and D+8), it was observed that 63.3% of patients had grade I and 33.3% had grade II disease; no patients had grade III or IV disease in this period. This severity of OM was similar to that seen in other studies of laser phototherapy and OM. Conclusion: The low grades of OM observed in this survey show the beneficial effects of laser phototherapy, but randomized clinical trials are necessary to confirm these findings.

Anti-Plasmodium Activity of Angiotensin II and Related Synthetic Peptides

Plasmodium species are the causative agents of malaria, the most devastating insect-borne parasite of human populations. Finding and developing new drugs for malaria treatment and prevention is the goal of much research. Angiotensins I and II (ang I and ang II) and six synthetic related peptides designated Vaniceres 1-6 (VC1-VC6) were assayed in vivo and in vitro for their effects on the development of the avian parasite, Plasmodium gallinaceum. Ang II and VC5 injected into the thoraces of the insects reduced mean intensities of infection in the mosquito salivary glands by 88% and 76%, respectively. Although the mechanism(s) of action is not completely understood, we have demonstrated that these peptides disrupt selectively the P. gallinaceum cell membrane. Additionally, incubation in vitro of sporozoites with VC5 reduced the infectivity of the parasites to their vertebrate host. VC5 has no observable agonist effects on vertebrates, and this makes it a promising drug for malaria prevention and chemotherapy.

Tamoxifen Is Effective in the Treatment of Leishmania amazonensis Infections in Mice

Background: Chemotherapy is still a critical issue in the management of leishmaniasis. Until recently, pentavalent antimonials, amphotericin B or pentamidine compounded the classical arsenal of treatment. All these drugs are toxic and have to be administered by the parenteral route. Tamoxifen has been used as an antiestrogen in the treatment and prevention of breast cancer for many years. Its safety and pharmacological profiles are well established in humans. We have shown that tamoxifen is active as an antileishmanial compound in vitro, and in this paper we analyzed the efficacy of tamoxifen for the treatment of mice infected with Leishmania amazonensis, an etiological agent of localized cutaneous leishmaniasis and the main cause of diffuse cutaneous leishmaniasis in South America. Methodology/Principal Findings: BALB/c mice were infected with L. amazonensis promastigotes. Five weeks post-infection, treatment with 15 daily intraperitoneal injections of 20 mg/kg tamoxifen was administered. Lesion and ulcer sizes were recorded and parasite burden quantified by limiting dilution. A significant decrease in lesion size and ulcer development was noted in mice treated with tamoxifen as compared to control untreated animals. Parasite burden in the inoculation site at the end of treatment was reduced from 10(8.5 +/- 0.7) in control untreated animals to 10(5.0 +/- 0.0) in tamoxifen-treated mice. Parasite load was also reduced in the draining lymph nodes. The reduction in parasite number was sustained: 6 weeks after the end of treatment, 10(15.5 +/- 0.5) parasites were quantified from untreated animals, as opposed to 10(5.1 +/- 0.1) parasites detected in treated mice. Conclusions/Significance: Treatment of BALB/c mice infected with L. amazonensis for 15 days with tamoxifen resulted in significant decrease in lesion size and parasite burden. BALB/c mice infected with L. amazonensis represents a model of extreme susceptibility, and the striking and sustained reduction in the number of parasites in treated animals supports the proposal of further testing of this drug in other models of leishmaniasis.

Antimicrobial photodynamic action on dentin using a light-emitting diode light source

Objective: The aim of this study was the evaluation of two different photosensitizers activated by red light emitted by light-emitting diodes (LEDs) in the decontamination of carious bovine dentin. Materials and Methods: Fifteen bovine incisors were used to obtain dentin samples which were immersed in brain-heart infusion culture medium supplemented with 1% glucose, 2% sucrose, and 1% young primary culture of Lactobacillus acidophilus 108 CFU/mL and Streptococcus mutans 108 CFU/mL for caries induction. Three different concentrations of the Photogem solution, a hematoporphyrin derivative (1, 2, and 3 mg/mL) and two different concentrations of toluidine blue O (TBO), a basic dye (0.025 and 0.1 mg/mL) were used. To activate the photosensitizers two different light exposure times were used: 60 sec and 120 sec, corresponding respectively to the doses of 24 J/cm(2) and 48 J/cm(2). Results: After counting the numbers of CFU per milligram of carious dentin, we observed that the use of LED energy in association with Photogem or TBO was effective for bacterial reduction in carious dentin, and that the greatest effect on S. mutans and L. acidophilus was obtained with TBO at 0.1 mg/mL and a dose of 48 J/cm(2). It was also observed that the overall toxicity of TBO was higher than that of Photogem, and that the phototoxicity of TBO was higher than that of Photogem. Conclusion: Based on our data we propose a mathematical model for the photodynamic effect when different photosensitizer concentrations and light doses are used.

Influence of Ecto-Nucleoside Triphosphate Diphosphohydrolase Activity on Trypanosoma cruzi Infectivity and Virulence

Background: The protozoan Trypanosoma cruzi is the causative agent of Chagas disease. There are no vaccines or effective treatment, especially in the chronic phase when most patients are diagnosed. There is a clear necessity to develop new drugs and strategies for the control and treatment of Chagas disease. Recent papers have suggested the ecto-nucleotidases (from CD39 family) from pathogenic agents as important virulence factors. In this study we evaluated the influence of Ecto-Nucleoside-Triphosphate-Diphosphohydrolase (Ecto-NTPDase) activity on infectivity and virulence of T. cruzi using both in vivo and in vitro models. Methodology/Principal Findings: We followed Ecto-NTPDase activities of Y strain infective forms (trypomastigotes) obtained during sequential sub-cultivation in mammalian cells. ATPase/ ADPase activity ratios of cell-derived trypomastigotes decreased 3- to 6-fold and infectivity was substantially reduced during sequential sub-cultivation. Surprisingly, at third to fourth passages most of the cell-derived trypomastigotes could not penetrate mammalian cells and had differentiated into amastigote-like parasites that exhibited 3- to 4-fold lower levels of Ecto-NTPDase activities. To evidence the participation of T. cruzi Ecto-NTPDase1 in the infective process, we evaluated the effect of known Ecto-ATPDase inhibitors (ARL 67156, Gadolinium and Suramin), or anti-NTPDase-1 polyclonal antiserum on ATPase and ADPase hydrolytic activities in recombinant T. cruzi NTPDase-1 and in live trypomastigotes. All tests showed a partial inhibition of Ecto-ATPDase activities and a marked inhibition of trypomastigotes infectivity. Mice infections with Ecto-NTPDase-inhibited trypomastigotes produced lower levels of parasitemia and higher host survival than with non-inhibited control parasites. Conclusions/Significance: Our results suggest that Ecto-ATPDases act as facilitators of infection and virulence in vitro and in vivo and emerge as target candidates in chemotherapy of Chagas disease.

Antimicrobial mechanisms behind photodynamic effect in the presence of hydrogen peroxide

This study describes the use of methylene blue (MB) plus light (photodynamic inactivation, PDI) in the presence of hydrogen peroxide (H(2)O(2)) to kill Staphylococcus aureus, Escherichia coli, and Candida albicans. When H(2)O(2) was added to MB plus light there was an increased antimicrobial effect, which could be due to a change in the type of ROS generated or increased microbial uptake of MB. To clarify the mechanism, the production of ROS was investigated in the presence and absence of H(2)O(2). It was observed that ROS production was almost inhibited by the presence of H(2)O(2) when cells were not present. In addition, experiments using different sequence combinations of MB and H(2)O(2) were performed and MB optical properties inside the cell were analyzed. Spectroscopy experiments suggested that the amount of MB was higher inside the cells when H(2)O(2) was used before or simultaneously with PDI, and ROS formation inside C. albicans cells confirmed that ROS production is higher in the presence of H(2)O(2). Moreover enzymatic reduction of MB by E. coli during photosensitizer uptake to the photochemically inactive leucoMB could be reversed by the oxidative effects of hydrogen peroxide, increasing ROS formation inside the microorganism. Therefore, the combination of a photosensitizer such as MB and H(2)O(2) is an interesting approach to improve PDI efficiency.