Effects of three organophosphorus insecticides in the reproductive potential of Culex quinquefasciatus

A Culex quinquefasciatus Say 1823 strain with resistant genes to organophosphates was tested in the laboratory to know the reproductive potential after exposure, as larvae, at the LC30 and LC70 (mg/l) of three organophosphorus insecticides: malathion, chlorpyrifos and methyl-pirimiphos. Data showed that fecundity was decreased significantly by malathion at LC30 = 0.0025 and LC70 = 0.0075, whereas fertility has a no significant decrement by chlorpyrifos and methyl-pirimiphos at the LC70 (0.000016, 0.00043). The sexual index was affected by chlorpyrifos and methyl-pirimiphos showing a greater number of adult females.

Oxidative potential of a panel of carbonaceous and metallic nanoparticles

Characterisation of nanoparticles (NP) based on size distribution, surface area, reactivity, and aggregation status of nanoparticles (NP) are of prime importance because they are usually closely related to toxicity. To date, most of the toxicity studies are quite time and money consuming. In the present study we report the oxidative properties of a panel of various NP (four Carbonaceous, nine Metal oxides, and one Metal as showed in Table 1) assessed with an acellular reactivity test measuring dithiothreitol (DTT) consumption (Sauvain et al. 2008). Such a test allows determining the ability of NP to catalyse the transfer of electrons from DTT to oxygen. DTT is used as a reductant species. NP were diluted and sonicated in Tween 80® to a final concentration of 50 g/mL. Printex 90 was diluted 5 times before doing the DTT assay because of its expected higher activity. Suspensions were characterised for NP size distribution by Nanoparticle Tracking Analysis (Nanosight©). Fresh solutions were incubated with DTT (100 μM). Aliquots were taken every 5 min and the remaining DTT was determined by reacting it with DTNB. The reaction rate was determined for NP suspensions and blank in parallel. The mean Brownian size distribution of NP agglomerates in suspension is presented in Table 1. D values correspond to 10th, and 50th percentiles of the particle diameters. All the NP agglomerated in Tween 80 with a D50 size corresponding to at least twice their primary size, except for Al2O3 (300 nm). The DTT test showed Printex 90 sample to be the most reactive one, followed by Diesel EPA and Nanotubes. Most of the metallic NP was nonresponding toward this test, except for NiO and Ag which reacted positively and ZnO which presented the most negative reactivity (see Figure 1). This last observation suggests that electron transfer between DTT and oxygen is hindered in presence of ZnO compared with the blank. Such "stabilization" could be attributable to ZnO dissolution and complexation between Zn2+ ions and DTT.

EIU in the rat promotes the potential of syngeneic retinal cells injected into the vitreous cavity to induce PVR.

PURPOSE: To determine whether syngeneic retinal cells injected in the vitreous cavity of the rat are able to initiate a proliferative process and whether the ocular inflammation induced in rats by lipopolysaccharide (LPS) promotes this proliferative vitreoretinopathy (PVR). METHODS: Primary cultured differentiated retinal Müller glial (RMG) and retinal pigmented epithelial (RPE) cells isolated from 8 to 12 postnatal Lewis rats were injected into the vitreous cavity of 8- to 10-week-old Lewis rats (10(5) cells/eye in 2 microlieter sterile saline), with or without the systemic injection of 150 microgram LPS to cause endotoxin-induced uveitis (EIU). Control groups received an intravitreal injection of 2 microliter saline. At 5, 15, and 28 days after cell injections, PVR was clinically quantified, and immunohistochemistry for OX42, ED1, vimentin (VIM), glial fibrillary acidic protein (GFAP), and cytokeratin was performed. RESULTS: The injection of RMG cells, alone or in combination with RPE cells, induced the preretinal proliferation of a GFAP-positive tissue, that was enhanced by the systemic injection of LPS. Indeed, when EIU was induced at the time of RMG cell injection into the vitreous cavity, the proliferation led to retinal folds and localized tractional detachments. In contrast, PVR enhanced the infiltration of inflammatory cells in the anterior segment of the eye. CONCLUSIONS: In the rat, syngeneic retinal cells of glial origin induce PVR that is enhanced by the coinduction of EIU. In return, vitreoretinal glial proliferation enhanced the intensity and duration of EIU.

The Effects of a DNA Virus Infection on the Reproductive Potential of Female Tsetse Flies, Glossina morsitans centralis and Glossina morsitans morsitans (Diptera: Glossinidae)

Reproductive anomalies associated with the tsetse DNA virus infection in the female tsetse hosts, Glossina morsitans centralis Machado and Glossina morsitans morsitans Westwood, inoculated with the virus during the 3rd instar larval stage were studied and the data compared to those obtained from the control females injected with sterile physiological saline. Virus infected flies had significantly longer first and second pregnancy cycles (P<0.0001) and produced pupae that were of significantly less weight in milligrams (P<0.0001) compared to controls. Transmission of the virus to progeny was not absolute and only 21% of G. m. centralis and 48% of G. m. morsitans first progeny flies from infected females developed salivary gland hypertrophy as a result of transmission from mother to progeny. The virus infected females produced significantly fewere pupae compared to the controls during the experimental period (P<0.00001).

Bone anabolic potential of soy isoflavones and plant extracts and genomic changes during differentiation of hPOB-tert osteoblast-like cells

Summary For the nutritional management of bone health and the prevention of osteoporosis it is important to identify nutrients that positively influence the bone remodeling process at the cellular level. Soy isoflavones show promising osteoprotective effects in animals and humans but their mechanism of action in bone cells is yet poorly understood. Firstly, soy tissue cultures were characterized as a new and optimized source of isoflavones. A large variability in the isoflavone content was observed and high-producing strains (46.3 mg/g dry wt isoflavones) were identified. In the Ishikawa cells bioassay, the estrogenicity of isoflavones was confirmed to be 1000 to 10000 less than 17Mestradiol and that of the malonyl forms was shown for the first time (EC50 of 350 nM and 1880 nM for malonylgenistin and malonyldaidzin, respectively). The estrogenic activity of soya tissue culture extracts correlated to their isoflavone content. Secondly, the effects of phytonutrients on BMP-2 gene expression and on the mevalonate synthesis pathway, as key mediators of bone formation, were investigated. Dietary achievable concentrations of genistein and daidzein (10vM), and statins (4xM) but not 17M estradiol (10nM), induced BMP-2 gene expression (by up to 3-fold) and inhibited the cholesterol biosynthetic pathway (by up to 50%) in the human osteoblastic cell line hP0B¬tert. In addition, several plant extracts (Cyperus rotundus, Lindera benzoin and Cnidium monnieri) induced BMP-2 gene expression but this induction was not restricted to the inhibition of the cholesterol synthesis pathway neither to the estrogenicity. Finally, the gene expression profiles during hP0B-tert differentiation induced by vitamin D and dexamethasone were analyzed with the Affymetrix human GeneChip. 1665 different genes and 98 ESTs were significantly regulated. The expression profiles of bone-related genes was largely in agreement with previously documented patterns, supporting the physiological relevance of the genomic results and the hP0B-tert cell line as a valid model of human osteoblast differentiation. The expression of alternative differentiation markers during the osteogenic treatment of hP0B-tert cells indicated that the adipocyte and myoblast differentiation pathways were repressed, confirming that these culture conditions allowed only osteoblast differentiation. The gene ontology analysis identified further sub-groups of genes that may be involved in the bone formation process. Aims of the thesis In order to define new strategies for the nutritional management of bone health and for the prevention of osteoporosis the major goal of the present work was to investigate the potential of phytonutrients to positively modulate the bone formation process at the cellular level and, in particular: 1.To select and optimise alternative plant sources containing high levels of isoflavones with estrogenic activity (Chapter 3). 2.To compare the effects of statins and phytonutrients on BMP-2 gene expression and on the mevalonate synthesis pathway and to select new plant extracts with a bone anabolic potential (Chapter 4). 3.To further characterize the new human periosteal cell line, hP0B-tert, as a bone- formation model, by elucidating its gene expression profile during differentiation induced by vitamin D and dexamethasone (Chapter 5).

Hyperglycemia-induced abnormalities in rat and human corneas: the potential of second harmonic generation microscopy.

BACKGROUND: Second Harmonic Generation (SHG) microscopy recently appeared as an efficient optical imaging technique to probe unstained collagen-rich tissues like cornea. Moreover, corneal remodeling occurs in many diseases and precise characterization requires overcoming the limitations of conventional techniques. In this work, we focus on diabetes, which affects hundreds of million people worldwide and most often leads to diabetic retinopathy, with no early diagnostic tool. This study then aims to establish the potential of SHG microscopy for in situ detection and characterization of hyperglycemia-induced abnormalities in the Descemet's membrane, in the posterior cornea. METHODOLOGY/PRINCIPAL FINDINGS: We studied corneas from age-matched control and Goto-Kakizaki rats, a spontaneous model of type 2 diabetes, and corneas from human donors with type 2 diabetes and without any diabetes. SHG imaging was compared to confocal microscopy, to histology characterization using conventional staining and transmitted light microscopy and to transmission electron microscopy. SHG imaging revealed collagen deposits in the Descemet's membrane of unstained corneas in a unique way compared to these gold standard techniques in ophthalmology. It provided background-free images of the three-dimensional interwoven distribution of the collagen deposits, with improved contrast compared to confocal microscopy. It also provided structural capability in intact corneas because of its high specificity to fibrillar collagen, with substantially larger field of view than transmission electron microscopy. Moreover, in vivo SHG imaging was demonstrated in Goto-Kakizaki rats. CONCLUSIONS/SIGNIFICANCE: Our study shows unambiguously the high potential of SHG microscopy for three-dimensional characterization of structural abnormalities in unstained corneas. Furthermore, our demonstration of in vivo SHG imaging opens the way to long-term dynamical studies. This method should be easily generalized to other structural remodeling of the cornea and SHG microscopy should prove to be invaluable for in vivo corneal pathological studies.

Predation Potential of the Water Bugs Sphaerodema rusticum on the Sewage Snails Physa acuta

The sewage snail Physa acuta is a serious threat to certain economic plants and to the purification plant of sewage works by rendering the biofilters ineffective. Various attempts are being made to control it. The efficacy of the predacious water bugs Sphaerodema rusticum was judged experimentally, in the laboratory in the potential control of P. acuta. It is revealed that, when supplied separately, the first, second and third instar and the adult S. rusticum did not attack P. acuta belonging to 3.1-8 mm, 5.1-8 mm, 7.1-8 mm and <= 3 mm size classes respectively. In the remaining trials predation rate varied from zero to eight (average 2.3) individuals per predator per day. In experiments with P. acuta belonging to all the size classes supplied together, none, except the first instar S. rusticum, attacked the prey individuals belonging to the lowest (<= 3 mm) size class. The first and second instar S. rusticum, in both trials did not attack P. acuta larger than 4 mm and 5 mm in shell length respectively. The water bugs belonging to the third, fourth, fifth instar and adult stages though preyed upon P. acuta with 3.1-8 mm shell length. The average rate of predation by a single S. rusticum varied from 0.14-3.08 individuals per day depending upon the size of P. acuta and the stage of S. rusticum. A single S. rusticum, irrespective of instar and adult stages, destroyed on average 4.16 P. acuta daily irrespective of sizes. It is estimated that one S. rusticum could destroy 1,360 P. acuta in its life time. The results clearly indicate that the water bug S. rusticum may be used to control the snails P. acuta.

Should Trypanosoma cruzi be called "cruzi" complex? A review of the parasite diversity and the potential of selecting population after in Vitro culturing and mice infection

Morpho-biological diversity of Trypanosoma cruzi has been known since Chagas' first works in 1909. Several further studies confirmed the morphological differences among the parasite strains, which were isolated from different reservoirs and vectors, as well as from human beings. In the early sixties, antigenic differences were found in the parasite strains from various sources. These differences, coupled to the observation of regional variations of the disease, led to the proposal of the term cruzi complex to designate the taxon T. cruzi. Since then this protozoan has been typed in distinct biodemes, zymodemes and lineages which were consensually grouped into T. cruzi I, T. cruzi II and into non-grouped strains. T. cruzi genotypic characterization, initially carried out by schizodeme analysis and more recently by various other techniques, has shown a great diversity of the parasite strains. In fact, T. cruzi is formed by groups of heterogeneous sub-population, which present specific characteristics, including distinct histotropism. The interaction of the different infecting clones of the cruzi complex and the human host will determine the morbidity of the disease.

High antigen concentration inhibits T cell proliferation but not interleukin 2 production: examination of limiting dilution microcultures and T cell clones.

The effect of high antigen dose on the activation of cytochrome c peptide-primed lymph node cells was determined in several strains of mice by a limiting dilution analysis. It was found that proliferation of cytochrome c peptide-specific T cells was completely inhibited at high antigen concentration in C57BL/6 but only partially in DBA mice and had no effect in SJL mice. Clones derived from DBA mice showed a differential capacity to be inhibited by high antigen dose. On the other hand, interleukin 2 production by these clones was not impaired regardless of the antigen concentrations used.

Mitochondrial reactive oxygen species generation triggers inflammatory response and tissue injury associated with hepatic ischemia-reperfusion: Therapeutic potential of mitochondrially targeted antioxidants.

Mitochondrial reactive oxygen species generation has been implicated in the pathophysiology of ischemia-reperfusion (I/R) injury; however, its exact role and its spatial-temporal relationship with inflammation are elusive. Herein we explore the spatial-temporal relationship of oxidative/nitrative stress and inflammatory response during the course of hepatic I/R and the possible therapeutic potential of mitochondrial-targeted antioxidants, using a mouse model of segmental hepatic ischemia-reperfusion injury. Hepatic I/R was characterized by early (at 2h of reperfusion) mitochondrial injury, decreased complex I activity, increased oxidant generation in the liver or liver mitochondria, and profound hepatocellular injury/dysfunction with acute proinflammatory response (TNF-α, MIP-1α/CCL3, MIP-2/CXCL2) without inflammatory cell infiltration, followed by marked neutrophil infiltration and a more pronounced secondary wave of oxidative/nitrative stress in the liver (starting from 6h of reperfusion and peaking at 24h). Mitochondrially targeted antioxidants, MitoQ or Mito-CP, dose-dependently attenuated I/R-induced liver dysfunction, the early and delayed oxidative and nitrative stress response (HNE/carbonyl adducts, malondialdehyde, 8-OHdG, and 3-nitrotyrosine formation), and mitochondrial and histopathological injury/dysfunction, as well as delayed inflammatory cell infiltration and cell death. Mitochondrially generated oxidants play a central role in triggering the deleterious cascade of events associated with hepatic I/R, which may be targeted by novel antioxidants for therapeutic advantage.

Potential of laticifer fluids for inhibiting Aedes aegypti larval development: evidence for the involvement of proteolytic activity

It has been shown previously that the laticifer fluid of Calotropis procera (Ait.) R.Br. is highly toxic to the egg hatching and larval development of Aedes aegypti L. In the present study, the larvicidal potential of other laticifer fluids obtained from Cryptostegia grandiflora R.Br., Plumeria rubra L. and Euphorbia tirucalli L. was evaluated. We attempted to correlate larvicidal activity with the presence of endogenous proteolytic activity in the protein fraction of the fluids. After collection, the fluids were processed by centrifugation and dialysis to obtain the soluble laticifer protein (LP) fractions and eliminate water insoluble and low molecular mass molecules. LP did not visibly affect egg hatching at the doses assayed. LP from Cr. grandiflora exhibited the highest larval toxicity, while P. rubra was almost inactive. E. tirucalli was slightly active, but its activity could not be correlated to proteins since no protein was detected in the fluid. The larvicidal effects of LP from C. procera and Cr. grandiflora showed a significant relationship with the proteolytic activity of cysteine proteinases, which are present in both materials. A purified cysteine proteinase (papain) from the latex of Carica papaya (obtained from Sigma) was similarly effective, whereas trypsin and chymotrypsin (both serine proteinases) were ineffective. The results provide evidence for the involvement of cysteine proteinase activity in the larvicidal action of some laticifer fluids. C. procera is an invasive species found in areas infested with Ae. aegypti and thus could prove useful for combating mosquito proliferation. This is the first report to present evidence for the use of proteolytic enzymes as chemical agents to destroy Ae. aegypti larvae.

Evaluation of the synergistic potential of vancomycin combined with other antimicrobial agents against methicillin-resistant Staphylococcus aureus and coagulase-negative Staphylococcus spp strains

Methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative Staphylococcus spp (CNS) are the most common pathogens that cause serious long term infections in patients. Despite the existence of new antimicrobial agents, such as linezolid, vancomycin (VAN) remains the standard therapy for the treatment of infections caused by these multidrug-resistant strains. However, the use of VAN has been associated with a high frequency of therapeutic failures in some clinical scenarios, mainly with decreasing concentration of VAN. This work aims to evaluate the synergic potential of VAN plus sulfamethoxazole/trimethoprim (SXT), VAN plus rifampin (RIF) and VAN plus imipenem (IPM) in sub-minimum inhibitory concentrations against 22 clinical strains of MRSA and CNS. The checkerboard method showed synergism of VAN/RIF and VAN/SXT against two and three of the 22 strains, respectively. The combination of VAN with IPM showed synergistic effects against 21 out of 22 strains by the E-test method. Four strains were analyzed by the time-kill curve method and synergistic activity was observed with VAN/SXT, VAN/RIF and especially VAN/IPM in sub-inhibitory concentrations. It would be interesting to determine if synergy occurs in vivo. Evidence of in vivo synergy could lead to a reduction of the standard VAN dosage or treatment time.

Lutzomyia longipalpis in Uruguay: the first report and the potential of visceral leishmaniasis transmission

Phlebotomine captures were performed in February 2010 in Salto (Salto department) and Bella Unión-Cuarein (Artigas department), Uruguay. Bella Unión is located across the Paraná River from Monte Caseros, Argentina, where a focus of canine visceral leishmaniasis (VL) was reported in 2009. No VL cases have ever been recorded in Uruguay and the last reported capture of Phlebotominae was in 1932 (Lutzomyia cortelezzii and Lutzomyia gaminarai). Light traps were placed in peridomestic environments, and Lutzomyia longipalpis, the main vector of visceral leishmaniasis, was found in Salto and Bella Unión. This is a first report of an area of potential VL transmission in Uruguay. Active and coordinated surveillance is required immediately the Uruguay-Argentina-Brazil border area.

Role and therapeutic potential of microRNAs in diabetes.

The discovery in mammalian cells of hundreds of small RNA molecules, called microRNAs, with the potential to modulate the expression of the majority of the protein-coding genes has revolutionized many areas of biomedical research, including the diabetes field. MicroRNAs function as translational repressors and are emerging as key regulators of most, if not all, physiological processes. Moreover, alterations in the level or function of microRNAs are associated with an increasing number of diseases. Here, we describe the mechanisms governing the biogenesis and activities of microRNAs. We present evidence for the involvement of microRNAs in diabetes mellitus, by outlining the contribution of these small RNA molecules in the control of pancreatic beta-cell functions and by reviewing recent studies reporting changes in microRNA expression in tissues isolated from diabetes animal models. MicroRNAs hold great potential as therapeutic targets. We describe the strategies developed for the delivery of molecules mimicking or blocking the function of these tiny regulators of gene expression in living animals. In addition, because changes in serum microRNA profiles have been shown to occur in association with different human diseases, we also discuss the potential use of microRNAs as blood biomarkers for prevention and management of diabetes.

Potential of education-based insulin therapy for achievement of good metabolic control: a real-life experience.

Diabet. Med. 28, 539-542 (2011) ABSTRACT: Aims  Achievement of good metabolic control in Type 1 diabetes is a difficult task in routine diabetes care. Education-based flexible intensified insulin therapy has the potential to meet the therapeutic targets while limiting the risk for severe hypoglycaemia. We evaluated the metabolic control and the rate of severe hypoglycaemia in real-life clinical practice in a centre using flexible intensified insulin therapy as standard of care since 1990. Methods  Patients followed for Type 1 diabetes (n = 206) or those with other causes of absolute insulin deficiency (n = 17) in our outpatient clinic were analysed in a cross-sectional study. Mean age (± standard deviation) was 48.9 ± 15.7 years, with diabetes duration of 21.4 ± 14.4 years. Outcome measures were HbA(1c) and frequency of severe hypoglycaemia. Results  Median HbA(1c) was 7.1% (54 mmol/mol) [interquartile range 6.6-7.8 (51-62 mmol/mol)]; a good or acceptable metabolic control with HbA(1c) < 7.0% (53 mmol/mol) or 7.5% (58 mmol/mol) was reached in 43.5 and 64.6% of the patients, respectively. The frequency of severe hypoglycaemic episodes was 15 per 100 patient years: 72.3% of the patients did not experience any such episodes during the past 5 years. Conclusions  Good or acceptable metabolic control is achievable in the majority of patients with Type 1 diabetes or other causes of absolute insulin deficiency in routine diabetes care while limiting the risk for severe hypoglycaemia.