Uptake and antileishmanial activity of meglumine antimoniate-containing liposomes in Leishmania (Leishmania) major-infected macrophages

Leishmaniasis is a parasitic disease caused by the intramacrophage protozoa Leishmania spp. and may be fatal if left untreated. Although pentavalent antimonials are toxic and their mechanism of action is unclear, they remain the first-line drugs for treatment of leishmaniasis. An effective therapy could be achieved by delivering antileishmanial drugs to the site of infection. Compared with free drugs, antileishmanial agent-containing liposomes are more effective, less toxic and have fewer adverse side effects. The aim of this study was to develop novel meglumine antimoniate (MA)-containing liposome formulations and to analyse their antileishmanial activity and uptake by macrophages. Determination of the 50% inhibitory concentration (IC(50)) values showed that MA-containing liposomes were >= 10-fold more effective than the free drug, with a 5-fold increase in selectivity index, higher activity and reduced macrophage toxicity. The concentration required to kill 100% of intracellular amastigotes was >= 40-fold lower when MA was encapsulated in liposomes containing phosphatidylserine compared with the free drug. Fluorescence microscopy analysis revealed increased uptake of fluorescent liposomes in infected macrophages after short incubation times compared with non-infected macrophages. In conclusion, these data suggest that MA encapsulated in liposome formulations is more effective against Leishmania-infected macrophages than the non-liposomal drug. Development of liposome formulations is a valuable approach to the treatment of infectious diseases involving the mononuclear phagocyte system. (C) 2011 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Submandibular and sublingual glands involvement in advanced acquired immunodeficiency syndrome (AIDS): an autopsy-based study

Objective. To assess the histopathological, immunohistochemical (IHC), and in situ hybridization (ISH) features found in the submandibular (SM) and sublingual (SL) glands of 105 acquired immunodeficiency syndrome (AIDS) patients at autopsy. Study design. Gender, age, CD4 cell level, and clinical histories were obtained from clinical charts (SM: n = 103; SL: n = 92). Histologic analysis of hematoxylin and eosin, Gomori-Grocott, and Ziehl-Neelsen stained tissues, IHC to detect infectious agents and characterize inflammatory cells in sialadenitis, and ISH for EBER-1/2 were performed. Results. The mean age of the patients and CD4 cell count were 36 years and 76 cells/mu L, respectively. Fifty-eight cases (SM: n = 51 [49%]; SL: n = 54 [59%]) were considered to be microscopically normal. The most common infectious conditions were mycobacteriosis (SM: n = 11 [10%]; SL: n = 7 [7%]), followed by cytomegalovirus (CMV) (SM: n = 14 [13%]; SL: n = 2 [2%]), and cryptococcosis (SM: n = 3 [3%]; SL: n = 4 [4%]). Human immunodeficiency virus (HIV) p24 (SM: n = 2 [2%]; SL: n = 1 [1%]) and EBER-1/2 (SM: n = 9 [39%]; SL: n = 4 [20%]) were seen only in macrophages and lymphocytes, respectively. The most prevalent cells seen in chronic nonspecific sialadenitis (SM: n = 25; SL: n = 25) were CD8+ T lymphocytes, whereas CD68+ macrophages were predominant in the mycobacteriosis-associated granulomatous and nonspecific diffuse macrophagic sialadenitis. Concomitant infections occurred in 5 cases (SM: n = 4; SL: n = 1) and non-Hodgkin lymphoma in 1 case. Conclusions. Infectious diseases and chronic nonspecific sialadenitis were the main alterations found in the SM and SL glands. These alterations were greater in the SM than in the SL glands. CD8+ T lymphocytes and CD68+ macrophages might be relevant to the pathogenesis of the sialadenitis. Clinicians should consider these diseases when assessing the major salivary glands in advanced AIDS patients and follow biosafety procedures to avoid contamination by HIV, CMV, mycobacteriosis, and cryptococcosis. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009; 108: 216-226)

Cost-effectiveness analysis of a hypothetical hepatitis C vaccine compared to antiviral therapy

We propose a mathematical model to simulate the dynamics of hepatitis C virus (HCV) infection in the state of Sao Paulo, Brazil. We assumed that a hypothetical vaccine, which cost was taken to be the initial cost of the vaccine against hepatitis B exists and it is introduced in the model. We computed its cost-effectiveness compared with the anti-HCV therapy. The calculated basic reproduction number was 1.20. The model predicts that without intervention a steady state exists with an HCV prevalence of 3%, in agreement with the Current epidemiological data. Starting from this steady state three interventions were simulated: indiscriminate vaccination, selective vaccination and anti-HCV therapy. Selective vaccination proved to be the strategy with the best cost-effectiveness ratio, followed by indiscriminate vaccination and anti-HCV therapy.

Dog culling and replacement in an area endemic for visceral leishmaniasis in Brazil

Measures employed to control visceral leishmaniasis in Brazil have focused on vector control by residual insecticide spraying and diagnosis of infection with elimination of positive dogs. We describe dog culling and replacement in a Brazilian endemic area (the Alvorada District, Aracatuba, SP) in order to better understand dog population dynamics when elimination of the dog reservoir is adopted as the main control measure. From August 2002 to July 2004, 60.9% of the estimated dog population for the area was culled with a mean age of 34 months old. The presence of anti-Leishmania sp. antibodies was recorded for only 26.7% of the euthanized canines. Replacement was observed in 38.8% of the cases, some of them by 2 or more dogs and in a mean time of 4 months. Dogs were replaced mostly by puppies of both sexes with a mean age of 6.8 months. From August 2002 to April 2005 we were able to follow-up 116 of these dogs, during a mean time of 8.7 months. Canine visceral leishmaniasis seropositivity by ELISA was observed in 42.2% of the followed dogs, 30.6% of which were already positive at the first evaluation. By the end of the follow-up period 37% of the dogs were submitted to euthanasia, with a mean age of 18.3 months. In the studied CVL endemic area of Brazil, euthanasia and the subsequent replacement ratio were high, increasing the dog population turnover and leading to a younger population that might be more susceptible to a variety of other infectious diseases in addition to CVL. Dog culling as a control strategy for VL should be reassessed. (C) 2008 Elsevier B.V. All rights reserved.