Erythrocytes morphology and hemorheology in severe bacterial infection.

BACKGROUND: Severe bacterial infections initiate inadequate inflammation that leads to disseminated intravascular coagulation and death. OBJECTIVES: To evaluate the influence of bacterial infection on blood viscosity and red blood cells (RBCs) morphology, and the ability of Calotropis procera proteins (CpLP) to prevent the patho-hemorheology in infected animals. METHODS: Rheology of blood, atomic force microscopy measurements on specific blood elements and blood count were performed to examine changes in blood viscosity, RBCs morphology, platelets activation, and RBCs indices. FINDINGS: Infected mice hold their blood rheological behaviour as compared to that of the control group. However, they presented hyperactivated platelets, RBCs at different stages of eryptosis, and variation on RBCs indices. CpLP administration in healthy animals altered blood behaviour from pseudoplastic to Bingham-like fluid. Such effect disappeared over time and by inhibiting its proteases. No alterations were observed in RBCs morphology or platelets. Treatment of infected animals with CpLP prevented the changes in RBCs indices and morphology. MAIN CONCLUSIONS: The inflammatory process triggered by bacterial infection induced pathological changes in RBCs and platelets activation. Treatment of infected animals with CpLP prevented the emergence of RBCs abnormal morphology and this may have implications in the protective effect of CpLP, avoiding animal death.

A phytomodulatory hydrogel with enhanced healing effects.

The healing performance of a hydrogel composed of hemicelluloses extracted from seeds of Caesalpinia pulcherrima (Fabaceae) and mixed with phytomodulatory proteins obtained from the latex of Calotropis procera was characterized on excisional wounds. The hydrogel did not induce dermal irritability. When topically used on excisional wounds, the hydrogel enhanced healing by wound contraction. Histology and the measurement of inflammatory mediators (myeloperoxidase, interleukin-1ß, and interleukin-6) suggested that the inflammatory phase of the healing process was intensified, stimulating fibroplasia and neovascularization (proliferative phase) and tissue remodeling by increasing new collagen fiber deposition. In addition, reduction on levels of malondialdehyde in the groups that the hydrogel was applied suggested that the oxidative stress was reduced. The hydrogel performed better than the reference drug used, as revealed by the extended thickness of the remodeled epithelium.

Phylogenetic characterization of serum plus antibiotic-resistant extraintestinal Escherichia coli obtained from the liver of poultry carcasses in Pernambuco / Caracterização filogenética de Escherichia coli extraintestinal soro- e antibiótico-resistentes isoladas do fígado de carcaças de frango em Pernambuco

In this study, avian extraintestinal Escherichia coli obtained from the liver of poultry carcasses approved for human consumption in the State of Pernambuco-Brazil were tested for antibiotic plus serum-resistance. Liver samples (n=110) were obtained from one slaughterhouse and 88 bacterial isolates were identified as Escherichia coli. The antibiotic-resistance profiles of antibiotics used in human and/or veterinary practice were accessed by the disk-diffusion method. Phenotypes with high resistance to streptomycin (84.0%), tetracycline (44.7%), amikacin (29.8%), gentamicin (21.3%) and ciprofloxacin (21.3%) were identified. Resistance to antibiotics such as ceftazidime, amoxicillin-clavulanic acid and imipenem was also recorded. Twenty isolates with distinct antibiotic-resistance and susceptibility profiles were selected for serum resistance assays, phylogenetic characterization and detection of the iss gene. We have shown that multidrug resistant isolates were often simultaneously resistant to broiler and human sera. Phylogenetic characterization of serum- plus antibiotic-resistant isolates have shown three belonging to group D, eleven to group B1, one to group B2, and five to group A. We concluded that commensal E. coli strains isolated from the liver of healthy poultry carcasses can harbor and potentially share multidrug- plus virulence genes found in pathogenic pathotypes. This suspicion was not related to specific phylogenetic groups or presence of the iss gene.(AU)

Neste estudo, isolados de Escherichia coli extraintestinal aviária obtidos a partir do fígado de carcaças de aves aprovadas para consumo humano no Estado de Pernambuco-Brasil foram testados para resistência a antibióticos e soro. As amostras de fígado (n = 110) foram obtidas de um abatedouro, sendo 88 isolados bacterianos identificados como Escherichia coli. Os perfis de resistência a antibióticos de uso humano e/ou veterinário foram determinados pelo método de disco-difusão. Foram identificados fenótipos com alta resistência à estreptomicina (84,0%), tetraciclina (44,7%), amicacina (29,8%), gentamicina (21,3%) e ciprofloxacina (21,3%). A resistência a antibióticos utilizados na medicina humana e/ou veterinária, tais como a ceftazidima, amoxicilina-ácido clavulânico, estreptomicina e imipenem também foi registrada. Vinte amostras com perfis distintos de resistência/sensibilidade a antibióticos foram selecionadas para os ensaios de resistência ao soro, caracterização filogenética e detecção do gene iss. Foi demonstrado que isolados resistentes a múltiplas drogas foram também simultaneamente resistentes ao soro de frangos e ao soro humano. A caracterização filogenética desses isolados mostraram três pertencentes ao grupo D, onze ao grupo B1, um ao grupo B2 e cinco ao grupo A. Conclui-se que E. coli comensais isoladas do fígado de carcaças de aves saudáveis podem abrigar e potencialmente compartilhar genes de resistência a drogas e de virulência encontrados em patotipos patogênicos. Essa suspeita não foi relacionada com grupos filogenéticos específicos ou com a presença do gene iss.(AU)

Latex proteins from Calotropis procera: Toxicity and immunological tolerance revisited.

Many thousands of plants are disseminated worldwide in traditional and folk medicines based on the belief that their leaves, roots, seeds, bark or secretions, when adequately handled, can treat, alleviate or ameliorate numerous disease symptoms. Calotropis procera (Apocynaceae) is a popular medicinal plant and the claims of this shrub's phytomedicinal properties have been scientifically validated. In this study, further prospects towards the in vivo toxicity and oral immunological tolerance of phytomodulatory proteins isolated from the latex of C. procera are reported. Acute toxicity was determined in mice by oral and intraperitoneal administration of latex proteins (LP) and was followed behavioral, hematological and histological analyses. Oral immunological tolerance to LP was assessed by intraperitoneal immunization in mice that had received LP orally before. Animals given 5000 mg/kg orally exhibited only discrete behavioral alterations and augmentation of monocytes. Death was not notified 14 days after exposure. However, all animals receiving LP 150 mg/kg by i.p. died in 1 h. Death (20%) was documented when LP (75 mg/kg) was given in the peritoneum and signs of harmful effects were observed in the survivors (80%). Oral immunological tolerance was observed in animals previously given LP orally, when they were further immunized/challenged with peritoneal exposure to different doses of LP. This was confirmed by the lowering of IgE and IgG in the serum, IL-4 and IFN-γ in spleen homogenates and the absence of anaphylaxis signs. It is therefore concluded that LP exhibited quite discrete adverse effects when orally administrated at higher concentrations and this route of administration did not stimulate adverse immunological reactions. Instead it was observed immunological tolerance. The present study contributes very important information concerning the safe use of C. procera as a phytotherapeutic agent.

First insights into the diversity and functional properties of chitinases of the latex of Calotropis procera.

Chitinases (EC 3.2.1.14) found in the latex of Calotropis procera (Ait) R. Br. were studied. The proteins were homogeneously obtained after two ion exchange chromatography steps. Most proteins were identified individually in 15 spots on 2-D gel electrophoresis with isoelectric points ranging from 4.6 to 6.0 and molecular masses extending from 27 to 30 kDa. Additionally, 66 kDa proteins were identified as chitinases in SDS-PAGE. Their identities were further confirmed by mass spectrometry (MS) analysis of the tryptic digests of each spot and MS analysis of the non-digested proteins. Positive reaction for Schiff's reagent suggested the proteins are glycosylated. The chitinases exhibited high catalytic activity toward to colloidal chitin at pH 5.0, and this activity underwent decay in the presence of increasing amounts of reducing agent dithiothreitol. Spore germination and hyphae growth of two phytopathogenic fungi were inhibited only marginally by the chitinases but were affected differently. This suggested a complex relationship might exist between the specificity of the proteins toward the fungal species. The chitinases showed potent insecticidal activity against the Bruchidae Callosobruchus maculatus, drastically reducing survival, larval weight and adult emergence. It is concluded that closely related chitinases are present in the latex of C. procera, and the first experimental evidence suggests these proteins are involved more efficiently in defence strategies against insects rather than fungi.

Comparison of immunomodulatory properties of mannose-binding lectins from Canavalia brasiliensis and Cratylia argentea in a mice model of Salmonella infection.

The immunomodulatory properties of mannose-binding lectins ConBr (Canavalia brasiliensis) and CFL (Cratylia argentea) were investigated comparatively in a model of Salmonella infection. The lectins were intraperitoneally (i.p.) administered to mice daily for three days before the bacterial challenge with Salmonella enterica Ser. Typhimurium (0.2 mL i.p.; 10(7) CFU/mL). In vivo assays have shown that both lectins induced a significant leukocyte infiltration into the peritoneal cavity of uninfected mice, which was higher in the CFL group 3 days post-infection. Total and differential cell counts in the bloodstreams have shown uninfected animals pretreated with ConBr and CFL exhibited accentuated lymphopenia. Conversely, there was an increasing population of lymphocytes following 3 days post-infection in mice pretreated with both lectins. In addition, the bacterial burden was significantly reduced into the peritoneal cavity, bloodstreams, spleen and the liver in these mice. The lectins did not induce the release of pro- or anti-inflammatory cytokines into the peritoneal fluid of uninfected animals. However, following infection, the release of TNF-α and IL-10 in the peritoneal fluid were down-regulated in mice pretreated with both lectins whereas IL-1 was only reduced in mice pretreated with ConBr. Uninfected animals pretreated with CFL exhibited high nitric oxide (NO) content in the peritoneal fluid, which was decreased after infection in comparison to ConBr group. The lectins did not alter the serum levels of NO in uninfected mice but treatments with ConBr significantly reduced the NO content in infected animals in comparison to CFL group 24h after the bacterial challenge. Survival experiments have shown survival rates ranging from 70% to 100% in mice that received CFL or ConBr. On the other hand, untreated mice (PBS group) died 1-6 days after infection. We conclude that ConBr and CFL are prospective phytotherapeutics capable of modulate the cascade of pro-inflammatory plus regulatory cytokines and nitric oxide release derived from systemic infections.

Inflammation induced by phytomodulatory proteins from the latex of Calotropis procera (Asclepiadaceae) protects against Salmonella infection in a murine model of typhoid fever.

OBJECTIVE AND DESIGN: Laticifer proteins (LP) of Calotropis procera were fractionated by ion-exchange chromatography, and the influence of a sub-fraction (LP(PI)) on the inflammatory response of Swiss mice challenged by Salmonella enterica Ser. Typhimurium was investigated. METHODS: Mice (n = 10) received LP(PI) (30 or 60 mg/kg) in a single inoculum by the intraperitoneal route 24 h before infection. To investigate the relevance of the proteolytic activity, three additional groups were included: the first one received heat-treated LP (30 mg/kg-30 min at 100 °C), the second received LP (30 mg/kg) inactivated by iodoacetamide, and a control group received only phosphate-buffered saline (PBS). RESULTS: The survival rate reached 100 % in mice treated with LP(PI) and was also observed with the other treatment, whereas the PBS group died 1-3 days after infection. The neutrophil infiltration into the peritoneal cavity of pretreated mice was enhanced and accompanied by high bacterial clearance from the bloodstream. Tumor necrosis factor-alpha mRNA transcripts, but not interferon-gamma, were detected early in spleen cells of pretreated mice after infection; however, the nitric oxide contents in the bloodstream were decreased in comparison to the PBS group. CONCLUSIONS: The inflammatory stimulus of C. procera proteins increased phagocytosis and balanced the nitric oxide release in the bloodstream, preventing septic shock induced by Salmonella infection.

Proteins derived from latex of C. procera maintain coagulation homeostasis in septic mice and exhibit thrombin- and plasmin-like activities.

The proteins derived from the latex (LP) of Calotropis procera are well known for their anti-inflammatory property. In view of their protective effect reported in the sepsis model, they were evaluated for their efficacy in maintaining coagulation homeostasis in sepsis. Intraperitoneal injection of LP markedly reduced the procoagulation and thrombocytopenia observed in mice infected with Salmonella; while in normal mice, LP produced a procoagulant effect. In order to understand its mechanism of action, the LP was subjected to ion-exchange chromatography, and the three subfractions (LPPI, LPPII, and LPPIII) thus obtained were tested for their proteolytic effect and thrombin- and plasmin-like activities in vitro. Of the three subfractions tested, LPPII and LPPIII exhibited proteolytic effect on azocasein and exhibited procoagulant effect on human plasma in a concentration-dependent manner. Like trypsin and plasmin, these subfractions produced both fibrinogenolytic and fibrinolytic effects that were mediated through the hydrolysis of the Aα, Bß, and γ chains of fibrinogen and α-polymer and γ-dimer of fibrin clot, respectively. This study shows that the cysteine proteases present in the latex of C. procera exhibit thrombin- and plasmin-like activities and suggests that these proteins have therapeutic potential in various conditions associated with coagulation abnormalities.

Proteins from latex of Calotropis procera prevent septic shock due to lethal infection by Salmonella enterica serovar Typhimurium.

AIM OF THE STUDY: The latex of Calotropis procera has been used in traditional medicine to treat different inflammatory diseases. The anti-inflammatory activity of latex proteins (LP) has been well documented using different inflammatory models. In this work the anti-inflammatory protein fraction was evaluated in a true inflammatory process by inducing a lethal experimental infection in the murine model caused by Salmonella enterica Subsp. enterica serovar Typhimurium. MATERIALS AND METHODS: Experimental Swiss mice were given 0.2 ml of LP (30 or 60 mg/kg) by the intraperitoneal route 24 h before or after lethal challenge (0.2 ml) containing 10(6) CFU/ml of Salmonella Typhimurium using the same route of administration. RESULTS: All the control animals succumbed to infection within 6 days. When given before bacterial inoculums LP prevented the death of mice, which remained in observation until day 28. Even, LP-treated animals exhibited only discrete signs of infection which disappeared latter. LP fraction was also protective when given orally or by subcutaneous route. Histopathological examination revealed that necrosis and inflammatory infiltrates were similar in both the experimental and control groups on days 1 and 5 after infection. LP activity did not clear Salmonella Typhimurium, which was still present in the spleen at approximately 10(4) cells/g of organ 28 days after challenge. However, no bacteria were detected in the liver at this stage. LP did not inhibit bacterial growth in culture medium at all. In the early stages of infection bacteria population was similar in organs and in the peritoneal fluid but drastically reduced in blood. Titration of TNF-alpha in serum revealed no differences between experimental and control groups on days 1 and 5 days after infection while IL-12 was only discretely diminished in serum of experimental animals on day 5. Moreover, cultured macrophages treated with LP and stimulated by LPS released significantly less IL-1beta. CONCLUSIONS: LP-treated mice did not succumb to septic shock when submitted to a lethal infection. LP did not exhibit in vitro bactericidal activity. It is thought that protection of LP-treated mice against Salmonella Typhimurium possibly involves down-regulation of pro-inflammatory cytokines (other than TNF-alpha). LP inhibited IL-1beta release in cultured macrophages and discretely reduced IL-12 in serum of animals given LP. Results reported here support the folk use of latex to treat skin infections by topic application.

Antibacterial and cytotoxic properties of some plant crude extracts used in Northeastern folk medicine / Propriedades antibacterianas e citotóxicas de alguns extratos de plantas usados na medicina popular nordestina

In the present study, 32 hexane and ethanol extracts of Protium bahianum, P. heptaphyllum, Croton sellowii, C. rhamnifolius, C. jacobinensis, C. micans and Muntingia calabura were screened for antibacterial activity by the disc-diffusion method. Cytotoxicity assays using the brine shrimp Artemia salina Leach as a model were performed to determine lethal doses for 50 percent of individuals (LC50 µg/mL). Antibacterial activity was found in flowers hexane extracts of M. calabura against B. subtilis, and leaves ethanol extracts against S. aureus and B. subtilis at concentration of 1mg/mL. Among 32 extracts, 19 showed low or no toxicity (LC50 > 250 µg/mL), 6 showed moderate toxicity (LC50 between 80 µg/mL and 250µg/mL), and 7 were highly toxic (LC50 < 80 µg/mL).

No presente estudo, 32 extratos hexânicos e etanólicos de Protium bahianum, P. heptaphyllum, Croton sellowii, C. rhamnifolius, C. jacobinensis, C. micans e Muntingia calabura, foram avaliados para atividade antibacteriana, pelo método de difusão em disco. Ensaios de citoxicidade foram realizados com o modelo do microcrustáceo Artemia salina Leach para determinar a concentração letal para 50 por cento dos indivíduos (CL50 µg/mL). A presença de atividade antibacteriana foi observada com os extratos hexânicos das flores de M. calabura contra B. subtilis, e extratos etanólicos das folhas contra S. aureus and B. subtilis na concentração de 1 mg/mL. Dentre os 32 extratos, 19 apresentaram toxicidade baixa ou ausente (CL50 > 250 µg/mL), 6 mostraram toxicidade moderada (CL50 entre 80 µg/mL e 250 µg/mL) e 7 foram muito tóxicos (CL50 < 80 µg/mL).