The effect of natural and organophilic palygorskite on skin wound healing in rats

In view of growing interest in natural treatments, clays would appear to be a good alternative for speeding up the healing process during the treatment of wounds. Of the various clays, palygorskite, a clay from the Brazilian State of Piauí, composed of silicon and aluminum, has shown itself to be pharmaceutically useful as a healing agent. The aim of this article is to evaluate the effect on the healing of wounds of Piauí palygorskite, both in its natural state and when organophilic, by way of comparative analysis of macroscopic and histological tests on skin wounds in adult male and female two-month-old Wistar rats. To this end, a circular trichotomy of the dorsal cornus of the rats was carried out to confirm the effects of treatments involving 0.9% saline solution, collagenase, natural palygorskite, organophilic palygorskite with cetyltrimethylammonium chloride, and organophilic palygorskite with alkyldimethylbenzylammonium chloride. The testing of all the clays involved microbiological evaluation using the depth of plaque and surface striation methods, along with post-treatment macroscopic analysis of skin wounds by way of organoleptics, pachymetry and histological analysis. Microbiological evaluation revealed the need for sterilization of the clay prior to incorporation in the pharmaceutical form. Macroscopic analysis suggests that healing of the wounded area occurred, and histological analysis showed the beneficial effect of the topical use of clay material. Our data suggest that palygorskite may be more powerful than other healing agents, although, on completing treatment, all the animals studied showed the same degree of tissue repair.Devido ao crescente interesse da população pelos tratamentos naturais, as argilas representam uma boa alternativa para a aceleração da cicatrização durante o tratamento de feridas. Dentre as argilas, a paligorsquita, uma argila piauiense, devido à sua composição com silício e alumínio, demonstra certa aplicabilidade farmacêutica como agente cicatrizante. O objetivo deste artigo é avaliar a ação cicatrizante da paligorsquita piauiense em sua forma natural e organofilizadas por meio da análise comparativa da macroscopia e dos exames histológicos em feridas cutâneas de ratos machos e fêmeas Wistar adultos com 2 meses de idade. Para tanto, foram realizadas tricotomia circular no corno dorsal dos ratos para verificar os efeitos dos tratamentos realizados com solução salina 0,9%, colagenase, paligorsquita natural, paligorsquita organofilizada por cloreto de cetiltrimetilamônio e paligorsquita organofilizada por cloreto de alquildimetilbenzilamônio. Para todas as argilas testadas foi feita a avaliação microbiológica pelo método de plaqueamento em profundidade e do método de estrias em superfície, bem como foi realizada após tratamento, a análise macroscópica das feridas cutâneas por meio organoléptico, medição em paquímetro e análise histológica. Por meio da avaliação microbiológica foi detectada a necessidade de esterilização da argila para posterior incorporação na forma farmacêutica. A análise macroscópica sugere que houve cicatrização da área lesionada, bem como a análise histológica demonstrou efeito benéfico após o uso tópico do material argiloso. Nossos dados sugerem que a paligorsquita pode exercer um maior efeito cicatrizante em relação aos demais tratamentos, embora após o término deste tratamento, todos os animais analisados apresentaram a mesma reparação tecidual

The Trypanosoma cruzi vitamin C dependent peroxidase confers protection against oxidative stress but is not a determinant of virulence.

BACKGROUND: The neglected parasitic infection Chagas disease is rapidly becoming a globalised public health issue due to migration. There are only two anti-parasitic drugs available to treat this disease, benznidazole and nifurtimox. Thus it is important to identify and validate new drug targets in Trypanosoma cruzi, the causative agent. T. cruzi expresses an ER-localised ascorbate-dependent peroxidase (TcAPx). This parasite-specific enzyme has attracted interest from the perspective of targeted chemotherapy. METHODOLOGY/PRINCIPAL FINDINGS: To assess the importance of TcAPx in protecting T. cruzi from oxidative stress and to determine if it is essential for virulence, we generated null mutants by targeted gene disruption. Loss of activity was associated with increased sensitivity to exogenous hydrogen peroxide, but had no effect on susceptibility to the front-line Chagas disease drug benznidazole. This suggests that increased oxidative stress in the ER does not play a significant role in its mechanism of action. Homozygous knockouts could proceed through the entire life-cycle in vitro, although they exhibited a significant decrease in their ability to infect mammalian cells. To investigate virulence, we exploited a highly sensitive bioluminescence imaging system which allows parasites to be monitored in real-time in the chronic stage of murine infections. This showed that depletion of enzyme activity had no effect on T. cruzi replication, dissemination or tissue tropism in vivo. CONCLUSIONS/SIGNIFICANCE: TcAPx is not essential for parasite viability within the mammalian host, does not have a significant role in establishment or maintenance of chronic infections, and should therefore not be considered a priority for drug design

Coinfection with Different Trypanosoma cruzi Strains Interferes with the Host Immune Response to Infection

A century after the discovery of Trypanosoma cruzi in a child living in Lassance, Minas Gerais, Brazil in 1909, many uncertainties remain with respect to factors determining the pathogenesis of Chagas disease (CD). Herein, we simultaneously investigate the contribution of both host and parasite factors during acute phase of infection in BALB/c mice infected with the JG and/or CL Brener T. cruzi strains. JG single infected mice presented reduced parasitemia and heart parasitism, no mortality, levels of pro-inflammatory mediators (TNF-α, CCL2, IL-6 and IFN-γ) similar to those found among naïve animals and no clinical manifestations of disease. On the other hand, CL Brener single infected mice presented higher parasitemia and heart parasitism, as well as an increased systemic release of pro-inflammatory mediators and higher mortality probably due to a toxic shock-like systemic inflammatory response. Interestingly, coinfection with JG and CL Brener strains resulted in intermediate parasitemia, heart parasitism and mortality. This was accompanied by an increase in the systemic release of IL-10 with a parallel increase in the number of MAC-3+ and CD4+ T spleen cells expressing IL-10. Therefore, the endogenous production of IL-10 elicited by coinfection seems to be crucial to counterregulate the potentially lethal effects triggered by systemic release of pro-inflammatory mediators induced by CL Brener single infection. In conclusion, our results suggest that the composition of the infecting parasite population plays a role in the host response to T. cruzi in determining the severity of the disease in experimentally infected BALB/c mice. The combination of JG and CL Brener was able to trigger both protective inflammatory immunity and regulatory immune mechanisms that attenuate damage caused by inflammation and disease severity in BALB/c mice

Factors influencing terrestriality in primates of the Americas and Madagascar

Among mammals, the order Primates is exceptional in having a high taxonomic richness in which the taxa are arboreal, semiterrestrial, or terrestrial. Although habitual terrestriality is pervasive among the apes and African and Asian monkeys (catarrhines), it is largely absent among monkeys of the Americas (platyrrhines), as well as galagos, lemurs, and lorises (strepsirrhines), which are mostly arboreal. Numerous ecological drivers and species-specific factors are suggested to set the conditions for an evolutionary shift from arboreality to terrestriality, and current environmental conditions may provide analogous scenarios to those transitional periods. Therefore, we investigated predominantly arboreal, diurnal primate genera from the Americas and Madagascar that lack fully terrestrial taxa, to determine whether ecological drivers (habitat canopy cover, predation risk, maximum temperature, precipitation, primate species richness, human population density, and distance to roads) or species-specific traits (bodymass, group size, and degree of frugivory) associate with increased terrestriality. We collated 150,961 observation hours across 2,227 months from 47 species at 20 sites in Madagascar and 48 sites in the Americas. Multiple factors were associated with ground use in these otherwise arboreal species, including increased temperature, a decrease in canopy cover, a dietary shift away from frugivory, and larger group size. These factors mostly explain intraspecific differences in terrestriality. As humanity modifies habitats and causes climate change, our results suggest that species already inhabiting hot, sparsely canopied sites, and exhibiting more generalized diets, are more likely to shift toward greater ground use

Factors influencing terrestriality in primates of the Americas and Madagascar

Among mammals, the order Primates is exceptional in having a high taxonomic richness in which the taxa are arboreal, semiterrestrial, or terrestrial. Although habitual terrestriality is pervasive among the apes and African and Asian monkeys (catarrhines), it is largely absent among monkeys of the Americas (platyrrhines), as well as galagos, lemurs, and lorises (strepsirrhines), which are mostly arboreal. Numerous ecological drivers and species-specific factors are suggested to set the conditions for an evolutionary shift from arboreality to terrestriality, and current environmental conditions may provide analogous scenarios to those transitional periods. Therefore, we investigated predominantly arboreal, diurnal primate genera from the Americas and Madagascar that lack fully terrestrial taxa, to determine whether ecological drivers (habitat canopy cover, predation risk, maximum temperature, precipitation, primate species richness, human population density, and distance to roads) or species-specific traits (body mass, group size, and degree of frugivory) associate with increased terrestriality. We collated 150,961 observation hours across 2,227 months from 47 species at 20 sites in Madagascar and 48 sites in the Americas. Multiple factors were associated with ground use in these otherwise arboreal species, including increased temperature, a decrease in canopy cover, a dietary shift away from frugivory, and larger group size. These factors mostly explain intraspecific differences in terrestriality. As humanity modifies habitats and causes climate change, our results suggest that species already inhabiting hot, sparsely canopied sites, and exhibiting more generalized diets, are more likely to shift toward greater ground use

Application of polyurethane resin from castor oil in controlled release gastroretentive dosage forms

Polímeros naturais têm sido amplamente utilizados como excipientes farmacêuticos, principalmente por serem biocompatíveis e renováveis. O objetivo deste estudo foi investigar a aplicação da resina poliuretânica derivada do óleo de mamona (RPDOM) em formas farmacêuticas gastrorretentivas de liberação controlada. O trabalho aqui apresentado está dividido em quatro capítulos. O capítulo 1 trata-se de uma visão geral sobre a aplicação dos poliuretanos como sistemas de liberação de fármacos, enfatizando os estudos contendo poliuretanos do óleo de mamona. O capítulo 2 trata-se de uma revisão sistemática sobre sistemas gastrorretentivos de liberação de fármacos. O capítulo 3 trata do desenvolvimento e da caracterização da RPDOM contendo fármaco na sua matriz. Domperidona e cloridrato de verapamil foram escolhidos como fármacos modelos devido ao potencial uso desses em formulações gastrorretentivas. Os estudos físico-químicos mostraram que parte da domperidona interagiu quimicamente com a RPDOM. Visto que não é possível a quebra dessa ligação química durante o estudo de dissolução, parte do fármaco ficou indisponível para liberação. Por outro lado, o verapamil foi incorporado com sucesso na RPDOM pelo método de evaporação do solvente. O verapamil interagiu através de forças intermoleculares com o polímero e esse sistema mostrou um promissor perfil de dissolução. O capítulo 4 trata do desenvolvimento de matrizes monolíticas flutuantes, contendo verapamil como fármaco modelo, espuma de polipropileno como excipiente de baixa densidade e um blend da RPDOM e da celulose microcristalina como sistema matricial. A capacidade de flutuação in vitro das matrizes e o controle da liberação do fármaco foram demonstrados. Por fim, a RPDOM mostrou-se um polímero promissor para o uso em sistemas de liberação controlada de fármacos devido a sua hidrofobicidade e para o uso em sistemas gastrorretentivos flutuantes devido à sua baixa densidade.Natural polymers have been extensively used as pharmaceutical excipients mainly due to their biocompatibility and renewability. The aim of this study was to investigate the application of polyurethane resin from castor oil (PU) in controlled release gastroretentive dosage forms. The work presented herein is divided in four chapters. Chapter 1 is an overview of the application of polyurethanes as drug delivery systems, emphasizing studies containing castor oil-based polyurethanes. Chapter 2 is a systematic review of gastroretentive drug delivery systems. Chapter 3 is about the development and characterization of the PU containing drug in its matrix. Domperidone and verapamil hydrochloride were chosen as model drugs due to their potential use in gastroretentive formulations. Physicochemical studies showed that part of domperidone interacted chemically with PU. Since it is not possible a cleavage of the chemical bond between domperidone and the polyurethane during the dissolution study, part of the drug was not available for release. On the other hand, verapamil was successfully incorporated into PU by solvent evaporation method. Verapamil interacted by intermolecular forces with the polymer and this system showed a promising drug dissolution profile. Chapter 4 shows the development of floating monolithic matrices, containing verapamil as model drug, polypropylene foam as low-density excipient and a blend of PU and microcrystalline cellulose as matrix-forming polymers. The in vitro buoyancy capability of the matrices and the ability to control drug release were demonstrated. Finally, PU proved to be a potential polymer to be used in controlled drug delivery systems due to its hydrophobicity and in gastroretentive floating systems due to its low density

Flow cytometry analysis of splenic MAC-3⁺ and NK cells from BALB/c mice infected with JG and/or CL Brener.

<p>Groups of mice were infected with 100 trypomastigotes of JG or CL Brener (single infection) or coinfected with 100 trypomastigotes of both <i>T. cruzi</i> populations in a 1∶1 ratio via the intraperitoneal route, and flow cytometry analysis of splenic MAC-3⁺ and NK cells was performed at 7, 14 and 21 days p.i. Symbols as follows: (A) TNF-α⁺/MAC-3⁺; (B) TNF-α⁺/NK; (C) IL-10⁺/MAC-3⁺; white bar: Naïve mice; light gray bar: JG infected mice; black bar: CL Brener infected mice; and dark gray bar: JG and CL Brener infected mice. Values are expressed as the mean ± SEM of three mice per group (representative of two independent experiments). *, † and ‡ represent <i>P</i><0.05 when compared with naïve, JG and CL Brener mouse groups, respectively.</p

Representative flow cytometry charts illustrating the cytokine synthesis by spleen MAC-3⁺ and CD4⁺ T cells from BALB/c mice infected with JG and/or CL Brener.

<p>Results are presented in density plot format. The analyses were performed by quadrant statistics expressed as the percentage of cytokine⁺ cells within gated MAC-3⁺ at 14 days p.i., and CD4⁺ cells at 14 and 21 days p.i. in splenocytes cultures from naïve, JG single infected, CL Brener single infected and JG and CL Brener coinfected mice. Cytokine flow cytometry charts demonstrate the enhanced percentage of cytokine⁺ cells in all infected mice. Outstanding levels of TNF-α-producing CD4⁺ T cells were contra balanced by high frequency of IL-10-producing MAC-3⁺ and CD4⁺ T cells in coinfected mice.</p