Colloidal Nanosilica Treatments for Sealing Cracks in Mortar.

Presence of microcracks in concrete can diminish the service life of a structure. The injection of materials for filling the crack is proposed for facing this problem. The traditional materials used for sealing cracks present some drawbacks, such as the difficulties of inorganic materials for flowing to all the depth of the crack and the lack of compatibility with the cementitious matrix in the case of organic materials. In this work, the injection of colloidal nanosilica dispersed in water is proposed for filling microcracks in mortars. The effect of the injection procedure on the sealing performance of the colloidal nanosilica has been assessed. The ability of colloidal nanosilica for penetrating through the crack and its posterior gelification-solidification inside the crack after a curing period have been confirmed. The microscopic analysis of a cross-section of the crack indicates that the sealing ability of the nanosilica seems to be not only due to the filling of the crack but also to chemical interactions with the cementitious phases of the surrounding crack sides.

Seropositivity for Trypanosoma cruzi and Leishmania mexicana in dogs from a metropolitan region of Central Mexico.

Trypanosoma cruzi and Leishmania mexicana are parasites of humans and other mammals, causing American Trypanosomiasis and Cutaneous Leishmaniasis, respectively. Domestic dogs are considered key hosts for these parasites in the domicile and peridomicile cycles of transmission, due to their abundance and contact with human population. In Mexico, there are few studies that involve the study of infection with these parasites in dogs, and have only been carried out mainly in the endemic areas for these diseases. In the state of Querétaro (Mexico), infections with both parasites have been reported for dogs only from rural areas, with no records for the metropolitan zone. We analyzed the seropositivity to T. cruzi and L. mexicana in dogs from localities within of the metropolitan zone of Querétaro City in order to determine if these animals are exposed to these parasites and thus, could be an important part of the transmission cycle of these trypanosomatids in a densely populated urban region within the state of Querétaro, Mexico. Serum samples were collected from 303 dogs housed in the Animal Control centers of the municipalities of Querétaro and El Marques, analyzed by indirect ELISA and Western Blot using as an antigen the Iron Superoxide Dismutase (FeSODe) of the parasites. From the total serum samples, we detected 10.2% of seropositivity for T. cruzi and 2.9% for L. mexicana. Our results represent the first evidence of infection with T. cruzi in domestic dogs from the Metropolitan Zone of Querétaro, and the first record for L. mexicana in Central Mexico. Ongoing investigations seek to confirm the circulation of these parasites in the area to evaluate the risk associated to the human population.

In vitro leishmanicidal and trypanocidal evaluation and magnetic properties of 7-amino-1,2,4-triazolo[1,5-a]pyrimidine Cu(II) complexes.

Two triazolopyrimidine complexes have been obtained from reaction between 7-amino-1,2,4-triazolo[1,5-a]pyrimidine (7atp) and Cu (II) salts. Crystal structures of [Cu2(µ-7atp)4Cl2]Cl2·4H2O (1) and [Cu2(µ-7atp)4(H2O)2](NO3)4·H2O (2) have been studied by X-ray diffraction methods and characterized by spectroscopic and thermal analysis. Magnetic studies of these dinuclear complexes have revealed the existence of moderate antiferromagnetic interactions between the copper ions, with J values of -91.2 and -96.1cm-1 respectively. It must be highlighted that the antiparasitic activity of these new complexes has been studied in vitro against three different strains of leishmania spp. and Trypanosoma cruzi, showing a higher efficacy than the 7atp ligand and the reference commercial drugs.

Antiparasitic activity against trypanosomatid diseases and novel metal complexes derived from the first time characterized 5-phenyl-1,2,4-triazolo[1,5-a]pyrimidi-7(4H)-one.

A serie of isostructural complexes with general formula [M(ftpO)2(H2O)4] have been obtained from reaction between the first time characterized triazolopyrimidine derivative 5-phenyl-1,2,4-triazolo[1,5-a]pyrimidi-7(4H)-one (HftpO) (1) and first row transition nitrates (M=Cu (2), Co (3), Ni (4) and Zn (5)). A copper complex with formula [Cu(HftpO)2(NO3)2(H2O)2]·H2O (6) was also isolated. HftpO and their metal complexes have been characterized by spectroscopic and thermal analysis and their crystal structures have been solved by X-ray diffraction methods. The isostructural compounds are mononuclear complexes where the triazolopyrimidine ligand acts as monodentate ligand through N3 nitrogen position. The crystal structure of these novel bis-5-phenyl-1,2,4-triazolo[1,5-a]pyrimidin-7(4H)-one-tetraaquo metal complexes offers an excellent opportunity at these complexes to acts as potential building blocks. Also, the antiparasitic activity of HftpO ligand against different leishmania and trypanosome strains has been studied.

Imidazole-containing phthalazine derivatives inhibit Fe-SOD performance in Leishmania species and are active in vitro against visceral and mucosal leishmaniasis.

The in vitro leishmanicidal activity of a series of imidazole-containing phthalazine derivatives 1-4 was tested on Leishmania infantum, Leishmania braziliensis and Leishmania donovani parasites, and their cytotoxicity on J774·2 macrophage cells was also measured. All compounds tested showed selectivity indexes higher than that of the reference drug glucantime for the three Leishmania species, and the less bulky monoalkylamino substituted derivatives 2 and 4 were clearly more effective than their bisalkylamino substituted counterparts 1 and 3. Both infection rate measures and ultrastructural alterations studies confirmed that 2 and 4 were highly leishmanicidal and induced extensive parasite cell damage. Modifications to the excretion products of parasites treated with 2 and 4 were also consistent with substantial cytoplasmic alterations. On the other hand, the most active compounds 2 and 4 were potent inhibitors of iron superoxide dismutase enzyme (Fe-SOD) in the three species considered, whereas their impact on human CuZn-SOD was low. Molecular modelling suggests that 2 and 4 could deactivate Fe-SOD due to a sterically favoured enhanced ability to interact with the H-bonding net that supports the antioxidant features of the enzyme.

Prospects of an alternative treatment against Trypanosoma cruzi based on abietic acid derivatives show promising results in Balb/c mouse model.

Chagas disease, caused by the protozoa parasite Trypanosoma cruzi, is an example of extended parasitaemia with unmet medical needs. Current treatments based on old-featured benznidazole (Bz) and nifurtimox are expensive and do not fulfil the criteria of effectiveness, and a lack of toxicity devoid to modern drugs. In this work, a group of abietic acid derivatives that are chemically stable and well characterised were introduced as candidates for the treatment of Chagas disease. In vitro and in vivo assays were performed in order to test the effectiveness of these compounds. Finally, those which showed the best activity underwent additional studies in order to elucidate the possible mechanism of action. In vitro results indicated that some compounds have low toxicity (i.e. >150 µM, against Vero cell) combined with high efficacy (i.e. <20 µM) against some forms of T. cruzi. Further in vivo studies on mice models confirmed the expectations of improvements in infected mice. In vivo tests on the acute phase gave parasitaemia inhibition values higher those of Bz, and a remarkable decrease in the reactivation of parasitaemia was found in the chronic phase after immunosuppression of the mice treated with one of the compounds. The morphological alterations found in treated parasites with our derivatives confirmed extensive damage; energetic metabolism disturbances were also registered by (1)H NMR. The demonstrated in vivo activity and low toxicity, together with the use of affordable starting products and the lack of synthetic complexity, put these abietic acid derivatives in a remarkable position toward the development of an anti-Chagasic agent.

In vitro leishmanicidal activity of pyrazole-containing polyamine macrocycles which inhibit the Fe-SOD enzyme of Leishmania infantum and Leishmania braziliensis species.

The in vitro leishmanicidal activity and cytotoxicity of pyrazole-containing macrocyclic polyamines 1-4 was assayed on Leishmania infantum and Leishmania braziliensis species. Compounds 1-4 were more active and less toxic than glucantime and both infection rates and ultrastructural alterations confirmed that 1 and 2 were highly leishmanicidal and induced extensive parasite cell damage. Modifications in the excretion products of parasites treated with 1-3 were also consistent with substantial cytoplasm alterations. Compound 2 was highlighted as a potent inhibitor of Fe-SOD in both species, whereas its effect on human CuZn-SOD was poor. Molecular modelling suggested that 2 could deactivate Fe-SOD due to a sterically favoured enhanced ability to interact with the H-bonding net that supports the enzyme`s antioxidant features.

Seroprevalence of antibodies against the excreted antigen superoxide dismutase by Trypanosoma cruzi in dogs from the Yucatan Peninsula (Mexico).

Numerous studies have shown the role of dogs as a reservoir for the American trypanosomiasis, as the bridge connecting sylvatic and peridomestic cycles. The objective of this study was to determine the prevalence of American trypanosomiasis in the dog population (630 sera) from seven localities in the Yucatan Peninsula (city of Mérida and the towns of Molas, Playa del Carmen, Akumal, Xcalacoop, Xcalac and Xahuachol). These data are key for developing control measures for the disease. The sera were analysed to detect antibodies against Trypanosoma cruzi, using Fe-SOD excreted as the antigenic fraction by ELISA and Western blot as confirmation. The total prevalence found in the Yucatan Peninsula was some 14.76%, with 10.74% in the state of Yucatan (city of Mérida, towns of Molas and Xcalacoop) and 21.34% in the state of Quintana Roo (towns of Playa del Carmen, Akumal, Xcalac and Xahuachol). However, a more thorough epidemiological study of the dog population, both wild and urban, in the Yucatan Peninsula will be required to design a control strategy for these diseases, paying particular attention to the population affected and even broadening the study to other Mexican states as well as neighbouring countries. These results again confirm that iron-superoxide dismutase excreted by T. cruzi constitutes a good source of antigen for serodiagnosis in epidemiological studies.

Leishmania spp. epidemiology of canine leishmaniasis in the Yucatan Peninsula.

Canine Leishmaniasis is widespread in various Mexican states, where different species of Leishmania have been isolated from dogs. In the present study, we describe the detection of L. braziliensis, L. infantum, and L. mexicana in serum of dogs from the states of Yucatan and Quintana Roo in the Yucatan Peninsula (Mexico). A total of 412 sera were analyzed by ELISA using the total extract of the parasite and the iron superoxide dismutase excreted by different trypanosomatids as antigens. We found the prevalence of L. braziliensis to be 7.52%, L. infantum to be 6.07%, and L. mexicana to be 20.63%, in the dog population studied. The results obtained with ELISA using iron superoxide dismutase as the antigen were confirmed by western blot analysis with its greater sensitivity, and the agreement between the two techniques was very high.

Seroprevalence to Trypanosoma cruzi in rural communities of the state of Querétaro (Mexico): statistical evaluation of tests.

OBJECTIVES: The detection of anti-Trypanosoma cruzi antibodies has become one of the priorities of the clinical establishments in the health sector, due both to the increase in positive cases found in transfusion centres as well as to the appearance of patients with characteristic Chagas cardiopathies that seek emergency treatment in the main hospitals of Querétaro (Mexico). DESIGN AND METHODS: The present study seeks to establish for the first time the infection level of Trypanosoma cruzi, in the rural communities of this state and implement the preventive measures necessary to control and/or eradicate this infection. A transversal study was conducted, examining seriologically 1029 blood samples of the inhabitants of rural areas of the state of Querétaro, to detect anti-Trypanosoma cruzi antibodies. RESULTS: The indirect serological diagnostic tests were indirect hemagglutination, enzymo-immunoenzymatic absorbent, recombinant ELISA, and indirect immunofluorescence. For the diagnostic evaluation of serological tests used, ELISA was considered the control test. CONCLUSIONS: The first conclusion was that the two tests with the greatest serological reactivity were ELISA and recombinant ELISA, followed by IFA and IHA, respectively, with the final percentage of positives being 6.6%, far above the national mean of seroprevalence in Mexico (1.6%). On the other hand, the sensitivity, specificity, VP+, VP-, percentage of concordance and Kappa index of the recombinant ELISA tests, IFA, and IHA were determined against the control ELISA. It was found that ELISA and recombinant ELISA presented a greater sensitivity level, as well as the highest values for the different parameters studied.

Intestinal parasitism in the animals of the zoological garden "Peña Escrita" (Almuñecar, Spain).

Gastrointestinal parasites cause serious diarrhoea in captive animals. Therefore, we have undertaken this study to establish programmes to prevent, control, and treat intestinal parasitism in the animals of the zoological garden "Peña Escrita" of Almuñecar (Granada). An annual survey was conduced to estimate the occurrence of gastrointestinal parasites and the seasonality of this parasitism. Between June 2006 and May 2007, 432 samples were collected from primates, carnivores, perissoodactyla, artiodactyla, rodentia, diprotodontia, galliformes, anseriformes and struthioniformes. One or more intestinal parasites were identified in 72.5% of the animals. The most frequent pathogenic endoparasites were Eimeria spp. (17.3%), Trichuris spp. (5.1%), Strongyloides spp. (4.5%), Cyclospora spp. (4.5%), Cryptosporidium spp. (3.2%) and Isospora spp. (2.6%). Iodamoeba butschlii, Parascaris equorum and Trichuris spp. did not vary with season and Cryptosporidium spp., Dicrocoelium dendriticum, Metastrongylus spp. and Cylicospirura spp. appeared exclusively in Artiodactyla. Multiple parasitic infections were common, 70% of animals presented with at least two parasites (maximum=6). The most frequent cases of multiple parasitism were Eimeria spp. plus Blastocystis spp. and Eimeria spp. plus Nematodirus spp., in the last case the animals presented explosive diarrhoea. In accord with our results, after each sampling, some of the affected animals were treated and the corresponding programmes of prevention and control were designed.

Prevalence of enteroparasites and genotyping of Giardia lamblia in Peruvian children.

Enteroparasites in children from three marginal urban districts of Trujillo (Peru) were studied to treat these children and to design a prevention and control programme. A total of 845 children were examined. The general prevalence of enteroparasites was of 66.3%, and 45.6% were multiparasitized. The pathogenic enteroparasite prevalence were 23.8% (Giardia lamblia), 4.6% (Iodamoeba buschlii), 2.6% (Cyclospora cayetanensis), 2.2% (Hymenolepis nana), and 2% (Cryptosporidium spp.). G. lamblia was the most frequent parasite both in diarrheic children (28.1%) as well as in nondiarrheic ones (19.5%). The G. lamblia genotypes were molecularly characterized by sequence analysis of the glutamate dehydrogenase (gdh) gene using PCR and RFLP. Sequence analysis revealed both Assemblage A (AI and AII) and Assemblage B (BIV), with the predominance of Assemblage AI. All the samples with Assemblage A were diarrheic but not those with Assemblage B. This is the first study of molecular characterization of G. lamblia in Peruvian children and confirms the importance of asymptomatic patients in the transmission of the giardiosis, especially in places with poor hygiene and sanitation.

More productive in vitro culture of Cryptosporidium parvum for better study of the intra- and extracellular phases.

The great difficulties in treating people and animals suffering from cryptosporidiosis have prompted the development of in vitro experimental models. Due to the models of in vitro culture, new extracellular stages of Cryptosporidium have been demonstrated. The development of these extracellular phases depends on the technique of in vitro culture and on the species and genotype of Cryptosporidium used. Here, we undertake the molecular characterization by polymerase chain reaction-restriction fragment length polymorphism of different Cryptosporidium isolates from calves, concluding that all are C. parvum of cattle genotype, although differing in the nucleotide at positions 472 and 498. Using these parasites, modified the in vitro culture technique for HCT-8 cells achieving greater multiplication of parasites. The HCT-8 cell cultures, for which the culture had not been renewed in seven days, were infected with C. parvum sporozoites in RPMI-1640 medium with 10% IFBS, CaCl2 and MgCl2 1 mM at pH 7.2. Percentages of cell parasitism were increased with respect to control cultures (71% at 48 h vs 14.5%), even after two weeks (47% vs 1.9%). Also, the percentage of extracellular stages augmented (25.3% vs 1.1% at 96 h). This new model of in vitro culture of C. parvum will enable easier study of the developmental phases of C. parvum in performing new chemotherapeutic assays.

More productive in vitro culture of Cryptosporidium parvum for better study of the intra- and extracellular phases

The great difficulties in treating people and animals suffering from cryptosporidiosis have prompted the development of in vitro experimental models. Due to the models of in vitro culture, new extracellular stages of Cryptosporidium have been demonstrated. The development of these extracellular phases depends on the technique of in vitro culture and on the species and genotype of Cryptosporidium used. Here, we undertake the molecular characterization by polymerase chain reaction-restriction fragment lenght polymorphism of different Cryptosporidium isolates from calves, concluding that all are C. parvum of cattle genotype, although differing in the nucleotide at positions 472 and 498. Using these parasites, modified the in vitro culture technique for HCT-8 cells achieving greater multiplication of parasites. The HCT-8 cell cultures, for which the culture had not been renewed in seven days, were infected with C. parvum sporozoites in RPMI-1640 medium with 10 percent IFBS, CaCl2 and MgCl2 1 mM at pH 7.2. Percentages of cell parasitism were increased with respect to control cultures (71 percent at 48 h vs 14.5 percent), even after two weeks (47 percent vs 1.9 percent). Also, the percentage of extracellular stages augmented (25.3 percent vs 1.1 percent at 96 h). This new model of in vitro culture of C. parvum will enable easier study of the developmental phases of C. parvum in performing new chemotherapeutic assays.

The use of an excreted superoxide dismutase in an ELISA and Western blotting for the diagnosis of Leishmania (Leishmania) infantum naturally infected dogs.

An excreted iron superoxide dismutase of pI 3.75 and a molecular mass of approximately 25 kDa was partially purified by QAE Sephadex ion-exchange chromatography from the in vitro culture of Leishmania (Leishmania) infantum. This enzyme was detected by enzyme-linked immunosorbent assay and Western blot of anti-L. infantum antibodies in dog serum. For the determination of the sensitivity and specificity of this protein, the results using the complete-parasite antigen fraction were taken as references. For this, 39 sera were assayed in dogs from different Spanish provinces. By Western blot, at a dilution of 1:250, 82% of the sera were positive when superoxide dismutase excreted was used as the antigen, against 56.4% positivity when the complete parasite was used as the antigen. These findings support the results of a previous study, indicating that the superoxide dismutase excreted can be useful in diagnosing L. (L.) infantum.

Effect of alkyl-lysophospholipids on some aspects of the metabolism of Leishmania donovani.

Alkyl-lysophospholipids (ALPs), developed initially to be antitumor agents, have proved highly effective in the treatment of visceral leishmaniasis, a disease caused by the species making up the protozoan complex Leishmania donovani. Although their effectiveness is known, the mode of action against this parasite is not completely understood. In the present work, we have studied the effect of 3 derivatives, edelfosine, miltefosine, and ilmofosine. Using nuclear magnetic resonance spectroscopy ('H-NMR), we have examined the excreted catabolites from glucose metabolism in the promastigote forms treated with these compounds. The ALPs at concentrations of 19 and 38 microM inhibit the excretion of acetate, succinate, and pyruvate. The effect of edelfosine, miltefosine, and ilmofosine on the activity of the enzymes hexokinase, glycerolkinase 3-PD, phosphoglucose isomerase, superoxide dismutase, and phospholipase C were also examined. Glycerolkinase 3-PD and phosphoglucose isomerase are generally insensitive to the compounds, whereas hexokinase and superoxide dismutase are inhibited by miltefosine and ilmofosine. The ALPs exhibited an activated effect against the phospholipase C activity. Alkyl-lysophospholipids were shown to have a significant effect on several enzymes in important biochemical pathways indispensable for the survival of L. donovani promasigotes.

[Proteus penneri]. / Proteus penneri.

Proteus penneri, formerly P. vulgaris biogroup 1, was recognized as a new species in 1982. This species is associated with clinical processes similar to those involving P. mirabilis and P. vulgaris and expresses similar pathogenic determinants. In clinical samples, P. penneri is mainly isolated from urine (50%), wound and soft tissue exudates (25%), and blood cultures (15%), mostly of nosocomial origin. Although P. penneri is easy to identify, it can be misidentified as P. vulgaris by automatic systems that do not include the indol test result in the identification process. This species has a characteristic susceptibility profile, essentially due to the production of the chromosomal inducible beta-lactamase HugA, which presents a high homology (86%) with CumA from P. vulgaris. HugA is inhibited by clavulanic acid and determines resistance to aminopenicillins and first- and second-generation cephalosporins, including cefuroxime, but does not affect cephamycins or carbapenems, and is inhibited by clavulanic acid. HugA is derepressed due to mutational processes in gene regulators, affecting the activity of cefotaxime and, to a much lesser extent, that of ceftazidime and aztreonam. This phenotype resembles the production of an extended spectrum beta-lactamase. Like other Proteus species, P. penneri is resistant to tetracyclines and should be considered resistant to nitrofurantoin.

Proteus penneri / Proteus penneri

Proteus penneri, anteriormente denominado Proteus vulgaris biogrupo 1, fue reconocido como especie nueva en 1982. Se asocia a procesos similares a los que producen Proteus mirabilis y Proteus vulgaris y comparte con ellos factores de patogenicidad. En muestras clínicas, se aísla esencialmente de orina (50%), exudados de piel y tejidos blandos (25%) y hemocultivos (15%), sobre todo en infección nosocomial. Su identificación no es problemática, aunque puede confundirse con P. vulgaris en los sistemas automáticos que no utilicen la prueba de indol en los procesos de identificación. Tiene un perfil de resistencia particular debido a la producción de la β-lactamasa cromosómica inducible HugA, con una elevada homología (86%) con CumA de P. vulgaris. HugA determina resistencia a aminopenicilinas y cefalosporinas de primera y segunda generación, incluyendo la cefuroxima, pero no afecta a las cefamicinas ni los carbapénemes, y se inhibe por el ácido clavulánico. La síntesis de HugA se desreprime debido a mutaciones en los genes reguladores, con lo que se afectan la actividad de la cefotaxima y, en mucha menor medida, la de la ceftazidima y el aztreonam. Este fenotipo puede confundirse con la producción de una β-lactamasa de espectro extendido. Al igual que otros Proteus penneri, es resistente a las tetraciclinas y debe considerarse resistente a la nitrofurantoína

Proteus penneri, formerly P. vulgaris biogroup 1, was recognized as a new species in 1982. This species is associated with clinical processes similar to those involving P. mirabilis and P. vulgaris and expresses similar pathogenic determinants. In clinical samples, P. penneri is mainly isolated from urine (50%), wound and soft tissue exudates (25%), and blood cultures (15%), mostly of nosocomial origin. Although P. penneri is easy to identify, it can be misidentified as P. vulgaris by automatic systems that do not include the indol test result in the identification process. This species has a characteristic susceptibility profile, essentially due to the production of the chromosomal inducible β-lactamase HugA, which presents a high homology (86%) with CumA from P. vulgaris. HugA is inhibited by clavulanic acid and determines resistance to aminopenicillins and first- and second-generation cephalosporins, including cefuroxime, but does not affect cephamycins or carbapenems, and is inhibited by clavulanic acid. HugA is derepressed due to mutational processes in gene regulators, affecting the activity of cefotaxime and, to a much lesser extent, that of ceftazidime and aztreonam. This phenotype resembles the production of an extended spectrum β-lactamase. Like other Proteusspecies, P. penneri is resistant to tetracyclines and should be considered resistant to nitrofurantoin