Gastroprotective activity and physicochemical analysis of carboxymethylated gum from Anadenanthera colubrina

Biotechnological advancements require the physicochemical alteration of molecules to enhance their biological efficacy for the effective treatment of gastric ulcers. The study aimed to produce a polyelectrolytic compound from red angico gum (AG) by carboxymethylation, evaluate its physicochemical characteristics and investigate gastric protection against ethanol-induced ulcers. AG and carboxymethylated angico gum (CAG) were characterized by Fourier transform infrared spectroscopy, determination of the degree of substitution and gel permeation chromatography (GPC) and 13C NMR techniques. The results demonstrated that the modification of the polymer was satisfactory, presenting conformational changes e improving the interaction with the gastric mucosa. AG and CAG reduced macroscopic and microscopic damage such as edema, hemorrhage and cell loss caused by exposure of the mucosa to alcohol. Both demonstrated antioxidant activity in vitro, and in vivo, pretreatment with gums led to the restoration of superoxide dismutase and glutathione levels compared to the injured group. Concurrently, the levels of malondialdehyde and nitrite decreased. Atomic force microscopy showed that CAG presented better conformational properties of affinity and protection with the gastric mucosa compared to AG in the acidic pH. Based on our findings, it is suggested that this compound holds promise as a prospective product for future biotechnological applications.

Hydrogels dressings based on guar gum and chitosan: Inherent action against resistant bacteria and fast wound closure

Hydrogels made with depolymerized guar gum, oxidized with theoretical oxidation degrees of 20, 35 and 50 %, were obtained via Schiff's base reaction with N-succinyl chitosan. The materials obtained were subjected to characterization by FT-IR, rheology, swelling, degradation, and morphology. Additionally, their gelation time categorized all three hydrogels as injectable. The materials' swelling degrees in Phosphate-Buffered Saline (PBS) were in the range of 26-35 g of fluid/g gel and their pore size distribution was heterogeneous, with pores varying from 67 to 93 μm. All hydrogels degraded in PBS solution, but maintained around 40 % of their initial mass after 28 days, which was more than enough time for wound healing. The biomaterials were also flexible, self-repairing, adhesive and cytocompatible and presented intrinsic actions, regardless of the presence of additives or antibiotics, against gram-positive (Staphylococcus aureus, Staphylococcus epidermidis) and gram-negative bacteria (Escherichia coli). However, the most pronounced bactericidal effect was against resistant Staphylococcus aureus - MRSA. In vivo assays, performed with 50 % oxidized gum gel, demonstrated that this material exerted anti-inflammatory effects, accelerating the healing process and restoring tissues by approximately 99 % within 14 days. In conclusion, these hydrogels have unique characteristics, making them excellent candidates for wound-healing dressings.

Influence of Reduction with NaBH4 and HCl in Obtaining Amino Derivatives of Cashew Gum and Cytotoxic Profile

Tree-exuded gums are natural polymers that represent an abundant raw material in the food and pharmaceutical industries. The cashew gum can be obtained by exudation of trees of the genus Anacardium, a native species of the Brazilian northeast; its polymer consists of monosaccharide units propitious to the action of chemical reactions that tend to improve their intrinsic characteristics among them, as the degree of hydro-solubility. The objective of this work was to modify the exudate gum of Anacardium occidentale (cashew gum (CG)) through an amine reaction. The modification was confirmed by Nuclear Magnetic Resonance (¹H NMR), infrared spectroscopy (FTIR), gel permeation chromatography (GPC), zeta potential, and thermogravimetric analysis (TG). In addition, the chemical modification altered the molar mass and surface charge of the CG, and the amino group binding to the CG polymers was confirmed by FTIR spectra. In addition, cytotoxicity tests were performed where cell viability was estimated by an MTT assay on RAW 264.7 macrophages. Through these tests, it was found that the amine caused an increase in the thermal stability of the amino compounds and did not present cytotoxic potential at concentrations below 50.0 mg/L.

Development of a New Clay-Based Aerogel Composite from Ball Clay from Piauí, Brazil and Polysaccharides

The incorporation of polymeric components into aerogels based on clay produces a significant improvement in the physical and thermal properties of the aerogels. In this study, clay-based aerogels were produced from a ball clay by incorporation of angico gum and sodium alginate using a simple, ecologically acceptable mixing method and freeze-drying. The compression test showed a low density of spongy material. In addition, both the compressive strength and the Young's modulus of elasticity of the aerogels showed a progression associated to the decrease in pH. The microstructural characteristics of the aerogels were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The chemical structure was studied by infrared spectroscopy with Fourier transform (FTIR). The TGA curves from a non-oxidizing atmosphere indicated that the clay had a mass loss of 9% above 500 °C and that due to the presence of polysaccharides, the aerogels presented a decomposition of 20% at temperatures above 260 °C. The DSC curves of the aerogels demonstrated a displacement in higher temperatures. In conclusion, the results showed that aerogels of ball clay with the incorporation of polysaccharides, which are still minimally studied, have potential application as thermal insulation considering the mechanical and thermal results obtained.

Vicilin from Anadenanthera colubrina Seeds: An alternative tool to combat Callosobruchus maculatus

Vicilins are seed proteins, and they constitute 70-80% of the total protein in leguminous seeds; with amolecular mass between 150 and 190 kDa, they are composed of subunits without disulfide bridges, with high affinity for chitin-binding. They are also associated with seed defense against insect pests. The chitin-binding vicilin from Anadenanthera colubrina seeds was purified by ammonium sulfate, followed by affinity chromatography on a chitin column, molecular exclusion on Superdex 75 Tricorn in FPLC system and Phenomenex C8 chromatography in HPLC system. The A. colubrina vicilin, named AcV, is a tetrameric glycoprotein composed of 1.55% carbohydrates and molecular weight determined by SDS-PAGE, consisting of 70, 73, 43 and 41 kDa. The AcV homogeneity was confirmed in native PAGE, where it was observed to be a unique band with slow mobility in this gel, with approximately 230 kDa. AcV added to the Callosobruchus maculatus diet in the bioassays resulted in a strong effect on adult emergence (ED50 of 0.096%), and in larvae caused a marked reduction in mass (WD50 of 0.32%) and lethality (LD50 of 0.33%) (w:w). The digestibility of AcV was evaluated in vitro with the digestive enzymes of larvae of C. maculatus of fourth instar, showing major fragments of 10 and 30 kDa. AcV showed reactivity against the anti-EvV antibody from Erythrina velutina vicilin. The deleterious effects of AcV are likely to be associated with the chitin-binding fragments generated by proteolysis in the bruchid gut, similarly to that found for vicilins from other leguminous plant species, Enterolobium contortisiliquum and Vigna unguiculata. AcV might be a candidate protein for a possible bioinsecticidal control of the bruchid weevil, C. maculatus.

Exploring the use of residual variance for uniformity of body weight in meat quail lines using Bayesian inference

1. Uniformity in animal products is an important aspect of the production system. Several studies have reported estimates of genetics on residual variance in different species, indicating that it could be exploited to improve uniformity by selection. Nevertheless, there are no reports about the possibilities of such a selection strategy in meat quail.2. Records of hatching weight (HW) and body weight at 42 days (W42) of female and male birds from two meat quail lines (UFV1 and UFV2) were analysed. A three-step genetic evaluation was used to investigate the effect of genetic variation on residual variance of HW and W42 in both lines. In Step 1, a single-trait model was fitted to the data. In Step 2, log-transformed squared estimated residuals (ln(ê²)) were evaluated for these traits. In Step 3, a multi-trait analysis was performed to estimate the genetic correlation between the additive genetic effects for HW, W42, and their respective ln(ê²).3. The heritability estimates ranged from 0.12 to 0.23 for HW and from 0.22 to 0.35 for W42. The estimated heritabilities for the residual part were low and ranged from 0.0003 to 0.02 for both traits, and the genetic coefficient of variation residual variance estimates ranged from 0.31 to 0.42 for HW and from 0.09 to 0.25 for W42. Genetic correlations between the means (HW and W42) and ln(ê²) values were both positive and did not differ from zero, indicating no association between mean and ln(ê²).4. In conclusion, the uniformity of HW and W42 could be improved by selecting for lower residual variance in both meat quail lines, but the accuracy of selection may be low due to low heritability for uniformity, mainly for W42.

Poly(ε-caprolactone) grafted cashew gum nanoparticles as an epirubicin delivery system

Polysaccharide based copolymers have been the focus of several research, particularly for the development of drug delivery systems. This study reports on the preparation of nanoparticles from an amphiphilic copolymer obtained by the poly(ε-caprolactone) graft in the structure of cashew gum, via ring-opening polymerization. The synthesis of copolymers was confirmed by Fourier transform infrared spectroscopy and nuclear magnetic resonance. The copolymers exhibit self-organization capability in water, with critical association concentration of 42 and 50 μg mL^-1. The nanoparticle hydrodynamic diameters (212 and 202 nm) revealed a decreasing trend with increasing poly(ε-caprolactone) graft percentage. Epirubicin was used as an anticancer drug model and incorporated into the nanoparticles. The encapsulation efficiency reached 50% and 5.0% drug load. Nanoparticles showed an epirubicin controlled release profile, with maximum release of 93.0 ± 4.0% in 72 h, as well as excellent biocompatibility, according to hemolysis and cytotoxicity assays.

Insights into the Antimicrobial Activity of Hydrated Cobaltmolybdate Doped with Copper

Molybdates are biocidal materials that can be useful in coating surfaces that are susceptible to contamination and the spread of microorganisms. The aim of this work was to investigate the effects of copper doping of hydrated cobalt molybdate, synthesized by the co-precipitation method, on its antibacterial activity and to elucidate the structural and morphological changes caused by the dopant in the material. The synthesized materials were characterized by PXRD, Fourier Transformed Infrared (FTIR), thermogravimetric analysis/differential scanning calorimetry (TG/DSC), and SEM-Energy Dispersive Spectroscopy (SEM-EDS). The antibacterial response of the materials was verified using the Minimum Inhibitory Concentration (MIC) employing the broth microdilution method. The size of the CoMoO₄·1.03H₂O microparticles gradually increased as the percentage of copper increased, decreasing the energy that is needed to promote the transition from the hydrated to the beta phase and changing the color of material. CoMoO₄·1.03H₂O obtained better bactericidal performance against the tested strains of Staphylococcus aureus (gram-positive) than Escherichia coli (gram-negative). However, an interesting point was that the use of copper as a doping agent for hydrated cobalt molybdate caused an increase of MIC value in the presence of E. coli and S. aureus strains. The study demonstrates the need for caution in the use of copper as a doping material in biocidal matrices, such as cobalt molybdate.

Zymosan enhances in vitro phagocyte function and the immune response of mice infected with Paracoccidioides brasiliensis

Paracoccidioides brasiliensis is the major etiologic agent of Paracoccidioidomycosis (PCM), the most frequent human deep mycosis in Latin America. It is proposed that masking of β-glucan in P. brasiliensis cell wall is a critical virulence factor that contributes to the development of a chronic disease characterized by a long period of treatment, which is usually toxic. In this context, the search for immunomodulatory agents for therapeutic purposes is highly desirable. One strategy is to use pattern recognition receptors (PRRs) ligands to stimulate the immune response mediated by phagocytes. Here, we sought to evaluate if Zymosan, a β-glucan-containing ligand of the PRRs Dectin-1/TLR-2, would enhance phagocyte function and the immune response of mice challenged with P. brasiliensis. Dendritic cells (DCs) infected with P. brasiliensis and treated with Zymosan showed improved secretion of several proinflammatory cytokines and expression of maturation markers. In addition, when cocultured with splenic lymphocytes, these cells induced the production of a potential protective type 1 and 17 cytokine patterns. In macrophages, Zymosan ensued a significant fungicidal activity associated with nitric oxide production and phagolysosome acidification. Importantly, we observed a protective effect of Zymosan-primed DCs delivered intranasally in experimental pulmonary PCM. Overall, our findings support the potential use of β-glucan-containing compounds such as Zymosan as an alternative or complementary antifungal therapy.

LAY SUMMARY

We report for the first time that Paracoccidioides brasiliensis-infected phagocytes treated with Zymosan (cell wall extract from bakers' yeast) show enhanced cytokine production, maturation, and fungal killing. Also, Zymosan-primed phagocytes induce a protective immune response in infected mice.

Genomic ancestry and metabolic syndrome in individuals with type 1 diabetes from an admixed population: a multicentre, cross-sectional study in Brazil

AIMS

To evaluate the relationship between self-reported colour-race, genomic ancestry, and metabolic syndrome in an admixed Brazilian population with type 1 diabetes.

METHODS

We included 1640 participants with type 1 diabetes. The proportions of European, African and Amerindian genomic ancestries were determined by 46 ancestry informative markers of insertion deletion. Two different sets of analyses were performed to determine whether self-reported colour-race and genomic ancestry were predictors of metabolic syndrome.

RESULTS

Metabolic syndrome was identified in 29.8% of participants. In the first model, the factors associated with metabolic syndrome were: female gender (odds ratio 1.95, P < 0.001); diabetes duration (odds ratio 1.04, P < 0.001); family history of type 2 diabetes (odds ratio 1.36, P = 0.019); and acanthosis nigricans (odds ratio 5.93, P < 0.001). Colour-race was not a predictive factor for metabolic syndrome. In the second model, colour-race was replaced by European genomic ancestry. The associated factors were: female gender (odds ratio 1.95, P < 0.001); diabetes duration (odds ratio 1.04, P < 0.001); family history of type 2 diabetes (odds ratio 1.39, P = 0.011); and acanthosis nigricans (odds ratio 6.12, P < 0.001). Physical exercise (≥3 times a week) was a protective factor (odds ratio 0.77, P = 0.041), and European genomic ancestry was not associated with metabolic syndrome but showed an odds ratio of 1.77 (P = 0.05).

CONCLUSIONS

Although a higher level of European genomic ancestry was observed among participants with metabolic syndrome in the univariate analysis, this association did not persist after multivariable adjustments. Further prospective studies in other highly admixed populations remain necessary to better evaluate whether the European ancestral component modulates the development of metabolic syndrome in type 1 diabetes.

Genotype by environment interaction for Holstein cattle populations using autoregressive and within- and across-country multi-trait reaction norms test-day models

The progenies of international bulls in diverse climatic conditions and management levels may lead to different expressions of their genetic potential resulting in a re-ranking of these bulls. Therefore, evaluate the presence of genotype by environment interaction (G×E) within and across countries is important to guide the decision-making on alternative selection strategies. Thus, a two-step reaction norm (RN) approach was used to investigate the presence of G×E in Portuguese and Brazilian Holstein cattle. In step 1, we performed a within-country genetic evaluation using an autoregressive model to obtain precorrected phenotypes and environmental gradients (herd test-day solutions, HTD levels). In step 2, the precorrected phenotypes were considered as two distinct traits in a bi-trait RN model to estimate variance components across HTD levels, genetic correlation between HTD levels in Portugal and Brazil, and RN of the estimated breeding values. Additionally, the genetic correlation between countries using a bi-trait random regression (RR) sire model was obtained. In step 1, genetic additive variance for milk yield (MY) in Portugal was 14.1% higher than in Brazil. For somatic cell score (SCS), the genetic additive variance in Portugal was 12.7% lower than in Brazil. Although similar heritability estimates for SCS were observed in both countries, MY heritabilities were 0.31 for Portugal and 0.23 for Brazil. Genetic correlations (SD) between both countries obtained using RR sire model were 0.78 (0.051) for MY and 0.75 (0.062) for SCS. In step 2, MY genetic correlations among HTD levels within countries were higher than 0.94 for Portugal and 0.98 for Brazil. Somatic cell score genetic correlations among HTD levels ranged from 0.70 to 0.99 for Portugal and from 0.84 to 0.99 for Brazil. The average (SD) of genetic correlation estimates between Portuguese and Brazilian HTD levels were 0.74 (0.009) for MY and 0.57 (0.060) for SCS. These results suggest the presence of G×E for MY and SCS of Holstein cattle between both countries. Although there was no indication of G×E between Brazilian herd environments, the low genetic correlation for SCS indicates potential re-ranking of bulls between extreme environmental gradient in Portugal. Overall, the results of this study evidence the importance of national and international genetic evaluation systems to assist dairy farmers in the selection of the best genotypes to obtain the expected returns from investments in imported semen and to realize genetic progress in dairy populations under local environmental conditions.

Sterculia striata gum as a potential oral delivery system for protein drugs

Natural polysaccharides have been investigated as vehicles for oral insulin administration. Because of their non-toxic, renewable, low cost and readily available properties, gums find multiple applications in the pharmaceutical industry. This work aimed to develop a Sterculia striata gum-based formulation associated with additional biopolymers (dextran sulfate, chitosan, and albumin), a crosslinking agent (calcium chloride) and stabilizing agents (polyethylene glycol and poloxamer 188), to increase the oral bioavailability of proteins. Insulin was used as a model drug and the methods used to prepare the formulation were based on ionotropic pregelation followed by electrolytic complexation of oppositely charged biopolymers under controlled pH conditions. The developed formulation was characterized to validate its efficacy, by the determination of its average particle size (622 nm), the insulin encapsulation efficiency (70%), stability in storage for 30 days, and the in vitro mucoadhesion strength (92.46 mN). Additionally, the developed formulation preserved about 64% of initial insulin dose in a simulated gastric medium. This study proposed, for the first time, a Sterculia striata gum-based insulin delivery system with potential for the oral administration of protein drugs, being considered a valid alternative for efficient delivery of those drugs.

Laryngeal Mucosa Alterations in Mice Model of Gastroesophageal Reflux: Effects of Topical Protection

OBJECTIVES/HYPOTHESIS

The objectives of this study were to evaluate laryngeal inflammation and mucosal integrity in a murine model of reflux disease and to assess the protective effects of topical agents including alginate, hyaluronic acid, and cashew gum.

STUDY DESIGN

Animal study.

METHODS

A surgical murine model of reflux disease was evaluated at 3 or 7 days postsurgery, and laryngeal samples were collected to measure inflammation (wet weight and myeloperoxidase [MPO]) and mucosal integrity (transepithelial resistance [TER] and mucosal permeability to fluorescein). Additional groups of animals were administered one of several topical agents (alginate, hyaluronic acid, or cashew gum) daily, and laryngeal inflammation and mucosal integrity were evaluated at 3 days postsurgery.

RESULTS

At 3 days, and not 7 days postsurgery, we observed increased laryngeal wet weight and MPO, decreased laryngeal TER, and increased laryngeal mucosa permeability. Alginate partially decreased laryngeal inflammation (wet weight and not MPO) and dramatically improved laryngeal mucosal integrity. Conversely, hyaluronic acid eliminated the inflammation; however, it had no effect on laryngeal mucosal integrity impairment. Cashew gum eliminated laryngeal inflammation as well as the impairment in laryngeal mucosal integrity.

CONCLUSIONS

This study shows that a surgical model of reflux disease induced laryngeal inflammation and impairment in laryngeal barrier function. These observed alterations were partially attenuated by alginate and hyaluronic acid and completely reversed by cashew gum.

LEVEL OF EVIDENCE

NA Laryngoscope, 2020.

Avaliação de Propriedades Mecânicas de Resinas Nanohíbridas Comerciais para Dentina

O objetivo do estudo foi avaliar a microdureza Knoop, o módulo de elasticidade e a resistência flexural de compósitos nanohíbridos para dentina. Foram utilizadas três resinas nanohíbridas comerciais: IPS Empress Direct (Ivoclar Vivadent) Aura (SDI) e Opallis (FGM). Para o teste de microdureza foram confeccionados seis corpos-de-prova para cada grupo, com uma matriz de silicona, medindo 5 mm de diâmetro e 2 mm de profundidade, fotopolimerizados por 40s. Foi utilizado microdurômetro com ponta Knoop com carga de 50 gf por 15 segundos em que cada corpo de prova recebeu 5 indentações, sendo calculada a média de cada espécime. As indentações foram realizadas na superfície que estava em contato com fita de poliéster. Os testes de resistência flexural e módulo de elasticidade foram realizados em uma máquina de ensaio universal com velocidade de carga de 1 mm/min com espécimes com formato de barra com dimensões 7mmx2mmx1mm. Os dados foram submetidos à ANOVA um fator e teste post hoc de Tukey com nível de confiança de 95%. Os resultados mostraram que houve diferença estatística significativa entre os grupos testados quanto   à microdureza (p0,723), módulo de elasticidade (p0,42) e resistência flexural (p0,386). A resina Opallis apresentou microdureza superior quando comparada às outras duas, assim como quando analisada a resistência flexural. Em relação ao módulo de elasticidade, a resina Opallis e Aura não apresentaram diferença estatística entre si, mas se mostraram com valor superior quando comparada a IPS Empress Direct.Palavras-chave: Composite. Resins. Nanohybrid. Classification.

Antidiarrheal activity of cashew GUM, a complex heteropolysaccharide extracted from exudate of Anacardium occidentale L. in rodents

ETHNOPHARMACOLOGICAL RELEVANCE

Anacardium occidentale L. (Anacardiaceae) is commonly known as the cashew tree. It is native to tropical America and extracts of the leaves, bark, roots, chestnut net and exudate have been traditionally used in northeast Brazil for the treatment of various diseases. The exudate of the cashew tree (cashew gum) has been exploited by locals since ancient times for multiple applications, including the treatment of diarrheal diseases.

AIM OF THE STUDY

The primary aim of the present study is to evaluate the antidiarrheal activity of cashew gum (CG), a complex heteropolysaccharide from the exudate of the cashew tree, using various models.

MATERIALS AND METHODS

The antidiarrheal activity of cashew gum (CG) against acute diarrhea was investigated using the castor oil-induced diarrhea model. The effects of CG on gastrointestinal transit and castor oil- and PGE2- induced enteropooling were also examined in rodents. In addition, the effect of CG against secretory diarrhea was investigated using a model of fluid secretion in cholera toxin-treated intestinal closed loops in live mice.

RESULTS

Cashew gum (30, 60, and 90 mg/kg, p.o.) showed a significant (P<0.05-0.01) antidiarrheal effect in rats with castor oil-induced diarrhea, inhibiting the total amount of stool and diarrheal stools. The 60 mg/kg dose of CG exhibited excellent antidiarrheal activity and significantly reduced the severity of diarrhea (diarrhea scores) in rats. CG (60 mg/kg) significantly (P<0.05) decreased the volume of castor oil- and PGE2-induced intestinal fluid secretion (enteropooling). In addition, similar to loperamide (standard drug, 5 mg/kg, p.o.), CG treatment reduced the distance traveled by a charcoal meal in the 30-min gastrointestinal transit model by interacting with opioid receptors. In cholera toxin-induced secretory diarrhea, CG (60 mg/kg) significantly inhibited the intestinal fluid secretion and decreased Cl(-) ion loss in the cholera toxin(-)treated isolated loops model of live mice by competitively binding to cholera toxin-GM1 receptors.

CONCLUSIONS

In conclusion, our results indicate that a complex heteropolysaccharide extracted from the exudate of A. occidentale L. has antidiarrheal activity in acute, inflammatory, and secretory diarrhea models, which could justify its traditional use in the treatment of diarrhea in northeast Brazil. The antidiarrheal activity might be explained by the capacity of CG to inhibit gastrointestinal motility and thereby reduce the accumulation of intestinal fluid and the secretion of water and chloride ions in the lumen of the intestine.

Sublingual immunization with the phosphate-binding-protein (PstS) reduces oral colonization by Streptococcus mutans

Bacterial ATP-binding cassette (ABC) transporters play a crucial role in the physiology and pathogenicity of different bacterial species. Components of ABC transporters have also been tested as target antigens for the development of vaccines against different bacterial species, such as those belonging to the Streptococcus genus. Streptococcus mutans is the etiological agent of dental caries, and previous studies have demonstrated that deletion of the gene encoding PstS, the substrate-binding component of the phosphate uptake system (Pst), reduced the adherence of the bacteria to abiotic surfaces. In the current study, we generated a recombinant form of the S. mutans PstS protein (rPstS) with preserved structural features, and we evaluated the induction of antibody responses in mice after sublingual mucosal immunization with a formulation containing the recombinant protein and an adjuvant derived from the heat-labile toxin from enterotoxigenic Escherichia coli strains. Mice immunized with rPstS exhibited systemic and secreted antibody responses, measured by the number of immunoglobulin A-secreting cells in draining lymph nodes. Serum antibodies raised in mice immunized with rPstS interfered with the adhesion of bacteria to the oral cavity of naive mice challenged with S. mutans. Similarly, mice actively immunized with rPstS were partially protected from oral colonization after challenge with the S. mutans NG8 strain. Therefore, our results indicate that S. mutans PstS is a potential target antigen capable of inducing specific and protective antibody responses after sublingual administration. Overall, these observations raise interesting perspectives for the development of vaccines to prevent dental caries.

Gastroprotective properties of cashew gum, a complex heteropolysaccharide of Anacardium occidentale, in naproxen-induced gastrointestinal damage in rats

Long-term use nonsteroidal anti-inflammatory drug is associated with gastrointestinal (GI) lesion formation. The aim of this study was to investigate the protective activity of cashew gum (CG), a complex heteropolysaccharide extracted from Anacardium occidentale on naproxen (NAP)-induced GI damage. Male Wistar rats were pretreated with vehicle or CG (1, 3, 10, and 30 mg/kg, p.o.) twice daily for 2 days; after 1 h, NAP (80 mg/kg, p.o.) was administered. The rats were euthanized on the 2nd day of treatment, 4 h after NAP administration. Stomach lesions were measured using digital calipers. The medial small intestine was used for the evaluation of macroscopic lesion scores. Samples of the stomach and the intestine were used for histological evaluation, and assays for glutathione (GSH), malonyldialdehyde (MDA), and myeloperoxidase (MPO). Additional rats were used to measure gastric mucus and secretion. Pretreatment with CG reduced the macroscopic and microscopic damage induced by NAP. CG significantly attenuated NAP-induced alterations in MPO, GSH, and MDA levels. Furthermore, CG returned adherent mucus levels to normal values. These results suggest that CG has a protective effect against GI damage via mechanisms that involve the inhibition of inflammation and increasing the amount of adherent mucus in mucosa.

The vasoactive peptide angiotensin-(1-7), its receptor Mas and the angiotensin-converting enzyme type 2 are expressed in the human endometrium

Angiotensin (Ang)-(1-7) is one of the major active components of the renin-angiotensin system, produced from cleavage of Ang II by angiotensin-converting-enzyme type 2 (ACE2), which acts through a specific G protein-coupled receptor, Mas. We have investigated whether the human endometrium expresses these components during menstrual cycle. By radioimmunoassay, Ang-(1-7) was detected in endometrial wash fluid at picomolar concentrations. Using immunofluorescence, both the peptide and its receptor were identified in cultured endometrial epithelial and stromal cells. By immunohistochemistry, Ang(1-7) was localized in the endometrium throughout menstrual cycle, being more concentrated in the glandular epithelium of mid- and late secretory phase. This pattern corresponded to the ACE2 mRNA, which was more abundant in epithelial cells than in stromal cells (2-fold increase, p < 0.05) and in the secretory vs. proliferative phase (6.6-fold increase, p < 0.01). The receptor Mas was equally distributed between epithelial and stromal cells and did not change during menstrual cycle. The physiological role of this peptide system in normal and pathological endometrium warrants further investigation.

Taxis but not private cars are mite allergen reservoirs in Brazil

Indoor allergens are major causative agents in allergic disease development. Besides homes, public transport vehicles have been considered important mite and pet allergen reservoirs. Our recent studies on allergen exposure in automobiles showed that different allergen levels are found in private cars versus taxis. We quantified group 1 Dermatophagoides spp. (Der 1), Felis domesticus (Fel d 1), and Canis familiaris (Can f 1) allergen levels by ELISA in dust samples from 60 taxi and 60 private car upholstered seats. Mean levels of Der 1 and Fel d 1 were significantly higher in taxis than private cars. A significantly higher percentage of taxis (42%) harboring sensitizing levels of Der 1 compared to private cars (5%) was also found. In spite of the low mean Fel d 1 levels, comparison of the percentage of vehicles with moderate Fel d 1 levels showed a significant difference between taxis and private cars (43% vs. 20%). On the other hand, mean Can f 1 levels were significantly higher in private cars compared to taxis concomitant with a significantly higher percentage of private cars containing moderate Can f 1 levels than taxis (53% vs. 28%). We conclude that upholstered seats from Brazilian taxis but not private cars constitute an important mite allergen reservoir. Thus, additional effective measures for the reduction of allergen exposure in vehicles within the global allergen avoidance strategy should also be routinely accomplished to minimize the induction of sensitization and symptoms in allergic patients.

High-speed horizontal-path atmospheric turbulence correction with a large-actuator-number microelectromechanical system spatial light modulator in an interferometric phase-conjugation engine

Results of atmospheric propagation for a high-speed, large-actuator-number adaptive optics system are presented. The system uses a microelectromechanical system- (MEMS-) based spatial light modulator correction device with 1024 actuators. Tests over a 1.35-km path achieved correction speeds in excess of 800 Hz and Strehl ratios close to 0.5. The wave-front sensor was based on a quadrature interferometer that directly measures phase. This technique does not require global wave-front reconstruction, making it relatively insensitive to scintillation and phase residues. The results demonstrate the potential of large-actuator-number MEMS-based spatial light modulators to replace conventional deformable mirrors.

Performance of a phase-conjugate engine implementing a finite-bit phase correction

The achievable Strehl ratio when a finite-bit correction to an aberrated wave front is implemented is examined. The phase-conjugate engine used to measure the aberrated wave front consists of a quadrature interferometric wave-front sensor, a liquid-crystal spatial light modulator, and computer hardware-software to calculate and apply the correction. A finite-bit approximation to the conjugate phase is calculated and applied to the spatial light modulator to remove the aberrations from the optical beam. The experimentally determined Strehl ratio of the corrected beam is compared with analytical expressions for the expected Strehl ratio and shown to be in good agreement with those predictions.

Statistical analyses of 14 short tandem repeat loci in Brazilian populations from Rio de Janeiro and Mato Grosso do Sul states for forensic and identity testing purposes

This work describes the statistical features of a database for two Brazilian populations (one from the Rio de Janeiro State (southeast region), and one from the Mato Grosso do Sul State (central western region) using fourteen short tandem repeat loci (STR).

Detection of IgG antibodies to Neospora caninum and Toxoplasma gondii in dogs examined in a veterinary hospital from Brazil

A total of 163 dogs with neuromuscular, respiratory and/or gastrointestinal disorders, was admitted at the Veterinary Hospital, Federal University of Uberlândia, Brazil, and submitted to serology for Toxoplasma gondii and Neospora caninum. Assays for T. gondii included indirect haemagglutination (IHA), indirect fluorescent antibody (IFAT-Tg), immunoenzymatic (ELISA), and immunoblotting (IB-Tg). Assays for N. caninum included IFAT-Nc and immunoprecipitation (IP-Nc). Based on concordant results by three serological tests (IHA, IFAT-Tg and ELISA) for T. gondii, and divergent results further confirmed by IB-Tg for reactivity to TgSAG1, the 163 sera were divided into two groups: 59 (36%) Tg-seropositive samples and 104 (64%) Tg-seronegative samples. Antibodies to Neospora were detected in 11 (6.7%) out of 163 analyzed dog sera, with 5 (3.1%) samples reactive to both parasites (Tg+/Nc+), and 6 (3.7%) reactive only to Neospora (Tg-/Nc+). Antibodies only to T. gondii were found in 54 (33%) samples. Among the 11 Neospora-positive sera analyzed by IB-Tg, the five sera Tg+/Nc+ showed strong reactivity to Toxoplasma antigens, especially to TgSAG1 (p30). No reactivity was observed to TgSAG1 in the six samples Tg-/Nc+. By IP-Nc, two highly immunodominant antigens (29 and 35kDa proteins) were recognized by all 11 IFAT-Nc positive sera. Our results suggest that the infection by N. caninum can be concomitantly present in dogs from this area, although less common, and therefore should be considered in the differential clinical diagnosis with T. gondii in dogs presenting neuromuscular, respiratory and/or gastrointestinal disorders.

Composition and effect of salt on rheological and gelation properties of Enterolobium contortisilliquum gum exudate

The composition, structure and rheological properties and metal ions interaction with Enterolobium contortisilliquum gum were investigated. This gum contains galactose, arabinose, rhamnose and glucuronic acid as main monosaccharide components. 13C nuclear magnetic resonance spectroscopy revealed that the anomeric composition is similar to the Enterolobium cyclocarpum exudate, however no 4-O-methylglucuronic acid was detected for E. contortisilliquum. The rheological experiment resulted in a very similar flow behaviour to that found for E. cyclocarpum gum. The empirical stiffness parameter, B was determined (B=0.090) and suggested that the polysaccharide possesses semi-flexible chains. Cation affinity of the gum aqueous solution was determined by intrinsic viscosity measurements and gelation. The melting temperature of gels pointed to a charge/ionic radius ratio dependence for metal ions. Thermodynamic parameters (enthalpy and entropy) at the melting temperature were also calculated.

Seroprevalence of Toxoplasma gondii infection in goats by the indirect haemagglutination, immunofluorescence and immunoenzymatic tests in the region of Uberlândia, Brazil

A comparative study of the indirect haemagglutination (IHA), immunofluorescence (IFAT) and immunoenzymatic (ELISA) tests was carried out to determine the prevalence of Toxoplasma gondii antibodies in goats. One hundred seventy-four serum samples were obtained from four goat herds from the region of Uberlândia, State of Minas Gerais. The distribution of the animals, according to their origin, was as follow: 71 from herd I; 39 from herd II; 37 from herd III; and 27 from herd IV. Serum samples were analyzed by IHA, IFAT and ELISA, considering the reactivity of the serum samples at dilution > or = 1:64 as cut off titer for the three tests. A global seroprevalence of 18.4% was observed, with significantly higher positivity rate in the herd II (66.7%) and older animals (> 36 months). A high and significant positive correlation was found between the titers obtained by the IHA versus IFAT, IHA versus ELISA, and ELISA versus IFAT. Therefore, it can be concluded that the three analyzed tests have shown to be highly concordant and appropriate for epidemiological surveys of Toxoplasma infection in goats. Although the seroprevalence of T. gondii infection in goats is relatively low in this region as compared to other regions of the country, adequate management might be useful and essential to control the infection in the goat herds.

A sensitive reverse ELISA for the measurement of specific IgE to Der p 2, a major Dermatophagoides pteronyssinus allergen

BACKGROUND

Epidemiologic studies have shown that the presence of IgE antibodies to house dust mite and other indoor allergens is an important risk factor for asthma.

OBJECTIVE

The aim of this study was to develop a reverse ELISA (rELISA) for measuring specific IgE to Der p 2, a major Dermatophagoides pteronyssinus (Dpt) allergen, as a potential tool for followup of allergen immunotherapy.

METHODS

Recombinant Der p 2 allergen or a monoclonal antibody to Der p 2 was used to coat plates in conventional ELISA (cELISA) and rELISA, respectively. Sera from 48 asthmatic patients with positive skin prick test (SPT+) to D. pteronyssinus extract were analyzed for total IgE and specific IgE to Der p 2, and the results were compared with a group of 41 SPT asthmatic and 30 SPT- control subjects.

RESULTS

The sensitivity of the two assays for Der p 2-specific IgE was 3.9 EU/mL and their specificities were confirmed by inhibition tests, in a dose-dependent manner. There was a significant positive correlation between cELISA and rELISA (r = 0.74; P < 0.0001). However, rELISA was more sensitive than was cELISA, regarding both the positive sera percentage (70.8% vs 52.1%) and the Der p 2-specific IgE levels (28.4 vs 4.5 EU/mL) in SPT+ asthmatic patients.

CONCLUSIONS

rELISA has shown to be a sensitive and alternative method for measuring Der p 2-specific IgE without using radioactive techniques. Detection of specific IgE to major allergens and relevant peptides, and identification of B cell epitopes in allergens will provide valuable information for the design of allergen analogs and peptides for immunotherapy.

Dermatophagoides farinae (Der f 1) and Dermatophagoides pteronyssinus (Der p 1) allergen exposure among subjects living in Uberlândia, Brazil

BACKGROUND

The role of mite allergen exposure in sensitization and development of asthma has been widely recognized. Previous studies have shown that Dermatophagoides pteronyssinus and Blomia tropicalis were the most prevalent house dust mites in Brazil, while D. farinae was rarely found. The aim of this study was to measure Der f 1 and Der p 1 allergen levels in Brazilian asthmatics' and controls' homes.

METHODS

Sixty-four houses (32 asthmatic, 32 control) were visited for dust sampling from five sites. Der f 1 and Der p 1 levels were measured by two-site monoclonal-antibody-based ELISAs.

RESULTS

The highest levels of Der f 1 and Der p 1 allergens were found in bedding samples from both asthmatics' and controls' homes. However, the geometric mean of Der f 1 levels (15.8 microgram/g of dust) was significantly higher than for Der p 1 (8.2 microgram/g of dust) in these samples. In addition, allergen levels >/=10 microgram/g of dust were found in 60-80% of the samples for Der f 1 and about 50% for Der p 1.

CONCLUSIONS

These results indicate that high levels of Der f 1 allergen are present in both asthmatics' and controls' homes, in contrast to previously reported data. Therefore, studies on exposure to mites should be performed in different cities, seasons and times, since the mite fauna might be subject to variations. Knowledge of the mite fauna will certainly improve the means of investigating the association between allergen exposure and sensitization, allowing to establish the inclusion of new mite extracts in inhalant skin test sets, and even to detect monosensitized patients with respiratory allergy.

Molecular markers in acute and chronic phases of human toxoplasmosis: determination of immunoglobulin G avidity by Western blotting

We characterized antigenic markers recognized by human serum samples from patients presenting with acute and chronic toxoplasmosis by the determination of immunoglobulin G (IgG) antibody avidity by a Western blot modified technique (avidity immunoblotting) that includes the dissociation of the antigen-antibody interaction with 6 or 8 M urea solutions. Human serum samples from 20 patients presenting with recent infection and from 20 patients with chronic infection were analyzed. It was observed that bands p16, p32, p38, p40, p43, p54, p60, p66, and p97 were more frequently recognized by low-avidity IgG in recent infection and by high-avidity IgG in chronic toxoplasmosis. From these antigenic bands, p38 can be characterized as an optimal antigenic marker of low avidity for recent forms of toxoplasmosis due to a significant decrease of their frequencies (from 80 to 0%) after treatment with 6 M urea solutions. The p30 antigen was not considered a good marker to distinguish acute from chronic infection since corresponding IgG antibodies were determined to have high avidity in both phases of the infection. Thus, the avidity immunoblotting assay proved to be a useful tool for determining antigenic markers of recent and chronic phases of Toxoplasma gondii infection.

Detection of Toxoplasma gondii soluble antigen, SAG-1(p30), antibody and immune complex in the cerebrospinal fluid of HIV positive or negative individuals

Active infection by T. gondii was evaluated by immunoassay for soluble SAG-1 (p30), the major surface antigen from T. gondii, specific antibodies and immune complexes in human cerebrospinal fluid (CSF) samples. A total of 263 samples of CSF were collected from hospitalized patients presenting neurological disorders and analyzed for antibodies to HIV. Patients were divided into two groups: HIV positive (n = 96) or HIV negative (n =167). The results of the assays showed that 45% of all samples were positive for soluble SAG-1. Toxoplasma Ag/Ab immune complexes were detected in 19% of the CSF samples and 62% were positive for T. gondii- specific IgG. A combination of these assays in the presence of clinical findings consistent with active Toxoplasma infection may predict the presence of toxoplasmic encephalitis. Moreover, detection of soluble SAG-1 in the CSF of these individuals appears consistent with active infection.

Evaluation of a synthetic tripeptide as antigen for detection of IgM and IgG antibodies to Trypanosoma cruzi in serum samples from patients with Chagas disease or viral diseases

An enzyme-linked immunosorbent assay (ELISA) has been developed to detect IgG and IgM antibodies in human sera against a synthetic tripeptide derived from a hybrid peptide containing 3 specific epitopes from Trypanosoma cruzi. This assay was compared in Brazil with one using conventional antigen, the alkaline crude extract. Serum samples were divided into positive (40 samples) or negative (107 samples) for Chagas disease. Positive samples included 9 serum samples from patients with acute Chagas disease, while negative samples included 57 samples from patients suffering from viral diseases. The total percentages of IgG positive samples from patients with chronic Chagas disease for alkaline extract and synthetic tripeptide were 93.5% and 100%, respectively. All samples from patients with acute Chagas disease were confirmed positive for IgM antibodies by using both the tripeptide and the alkaline extract. However, the results for anti-T. cruzi IgM in the group of chronic Chagas disease patients demonstrated that 41.9% were positive for IgM with the alkaline extract, while the synthetic peptide showed a significantly lower number of positive samples (12.9%). The serum samples from healthy people showed similar results for both antigens. However, 40% of the serum samples from patients presenting with viral diseases were IgM positive for Chagas disease when assayed with conventional antigen; with the synthetic tripeptide as antigen, 100% of this group of samples were found to be negative. Thus, as the results of ELISA with synthetic tripeptide showed higher rates of sensitivity and specificity than ELISA with conventional antigen, the former should be included as a laboratory tool in the serodiagnosis of Chagas disease.

Calomys callosus (Rodentia : Cricetidae) trophoblast cells as host cells to Toxoplasma gondii in early pregnancy

The potential of the RH strain of Toxoplasma gondii to invade trophoblast cells of the cricetid rodent Calomys callosus in a congenital infection in the initial third of pregnancy was investigated in this study using morphological and immunocytochemical approaches. The animals were intraperitoneally inoculated on the 1st day of pregnancy and the infection was observed on day 7. Various numbers of parasites could be observed inside the parasitophorous vacuoles in trophoblastic cells under light and electron microscopy. The trophoblast cells showed characteristics of healthy cells, and no alteration other than parasite vacuoles in their cytoplasm could be detected. Polyclonal or monoclonal anti-T. gondii antibodies (respectively, anti-T. gondii components and the major surface parasite antigen p30) labeled both the parasite surface and parasitophorous vacuole membranes, regardless of the number of parasites inside the compartment. In addition, p30-containing trails were detected in the extracellular matrix surrounding trophoblastic cells similar to those found with other parasites during locomotion and the invasion process. Our results show the ability of T. gondii to infect trophoblast cells during the early blastocyst-endometrial relationship and open new possibilities for more accurate study of the invasion process of this parasite and the role of the trophoblast as an embryo defense barrier.

Acquired and congenital ocular toxoplasmosis experimentally induced in Calomys callosus (Rodentia, Cricetidae)

An experimental model for acquired and congenital ocular toxoplasmosis as well as a model to induce experimental autoimmune uveitis (EAU) was investigated in Calomys callosus. Toxoplasma gondii, ME-49 strain, was used to infect males and pregnant- and not pregnant-females while S-antigen, a major glycoprotein of the retinal photoreceptor cell, was used to induce EAU. The ocular lesions elicited by T. gondii were characterized by the presence of cysts, free tachyzoites and inflammatory cells in the retina or related tissues. In the congenital form, 40% of the fetus presented ocular lesions, i.e., presence of cysts in the retina, vitreous, and extra-retinal tissues. In the acquired form, 75% of the females and 50% of the males presented unilateral ocular cysts both at 21 and 47 days post-infection. It was also demonstrated that S-antigen was not uveitogenic in the C. callosus model. No lesion was observed in the animals exclusively immunized with this retinal component, even when jacalin was used as additional adjuvant for polyclonal response to the retinal antigen. It can be concluded that C. callosus may constitute in a promising model for study both acquired and congenital ocular toxoplasmosis, particularly when it is important to make sure that a non autoimmune process is involved in the genesis of the ocular infection.

Expression of Toxoplasma gondii-specific heat shock protein 70 during In vivo conversion of bradyzoites to tachyzoites

Stage conversion between bradyzoites and tachyzoites was investigated in C57BL/6 mice chronically infected with the ME-49 strain of Toxoplasma gondii. In order to promote bradyzoite-tachyzoite conversion, mice were treated in vivo with neutralizing doses of anti-gamma interferon (IFN-gamma) or anti-tumor necrosis factor alpha (TNF-alpha) antibodies. Expression of parasite-specific antigens SAG-1, SAG-2, and heat shock protein 70 (Hsp-70) was visualized in the central nervous system by immunocytochemistry and measured by photometric assay. The immunosuppressive effect of anti-IFN-gamma or anti-TNF-alpha treatment was immediate, leading to parasite stage conversion as indicated by the increased expression of tachyzoite-specific antigens (SAG-1 and SAG-2) and by rapid parasite replication. We also observed expression of high levels of Hsp-70 during a short period of conversion of bradyzoites to tachyzoites. Our data suggest that Hsp-70 may have an important role in the process of bradyzoite-tachyzoite conversion during the reactivation of chronic toxoplasmosis.

Experimental infection of Calomys callosus (Rodentia, Cricetidae) by Toxoplasma gondii

Calomys callosus, Rengger 1830 (Rodentia, Cricetidae), a wild rodent found in Central Brazil, was studied to investigate its susceptibility to Toxoplasma gondii experimental infection and its humoral immune response against this protozoa. The electrophoretic profile of the serum proteins of C. callosus showed that IgG, which shows no affinity to Protein A, has higher cross reactivity with rat IgG than with IgG from other rodents. The susceptibility assay was performed by inoculation groups of animals with various suspensions of T. gondii tachyzoites from 10(2) to 10(6) parasites. All animals died between 3 and 9 days after infection and the kinetics of antibody synthesis was determined. Basically, they recognized predominantly the immunodominant antigen SAG-1 (P30). The immunohistochemistry assays revealed that the liver was the most heavily infected organ, followed by the spleen, lungs, intestine, brain and kidneys. It can be concluded that C. callosus is an excellent experimental model for acute phase of Toxoplasma infection.

Detection of Toxoplasma gondii-specific antibodies in dogs. A comparative study of immunoenzymatic, immunofluorescent and haemagglutination titers

We evaluated the titers of anti-T. gondii antibodies by various serological tests in 40 serum samples from dogs exhibiting clinical signs of infectious diseases. Indirect immunofluorescence (IgG-IFI), indirect haemagglutination (IHA and M-Toxo) and immunoenzymatic (ELISA and PA-ELISA) tests were carried out. Titers > or = 64 were considered as positive. Anti-Toxoplasma antibodies were found in 9 (22.5%), 14 (35%), 14 (35%) and 12 (30%) samples, respectively for IHA, IgG-IFI, ELISA and PA-ELISA. The results showed that 57% were negative in all tests and 43% of the dogs presented antibodies to T. gondii; from these, 20% were positive in all three tests with high titers of antibodies and 23% were positive in only one or two tests with low titers of antibodies and mainly related to the IFI and ELISA tests. We observed 5 (12.5%) and 1 (2.5%) reactive samples, respectively, by M-Toxo and IHA with or without 2-mercapthoethanol, in the attempt to detect specific IgM. We can conclude that serodiagnosis of toxoplasmosis in dog have to be based on the combination of serological tests (IFI and ELISA) and with emphasis at the determination of the titers and the classes of the specific antibodies.

Toxoplasmosis in naturally infected deer from Brazil

Serum samples from 107 cervids were examined for Toxoplasma gondii antibodies using indirect hemagglutination (IHA), indirect immunofluorescence (IFA), enzyme linked immunosorbent assay (ELISA) and Dot-ELISA. Samples were obtained from 66 marsh deer (Blastocerus dichotomus) in the State of São Paulo (Brazil) and from 41 pampas deer (Ozotocerus bezoarticus) in the State of Goiás (Brazil). Antibodies to T. gondii were found in 23 (22%) of the deer, with 18 and 5 positive samples, respectively, for B. dichotomus and O. bezoarticus. The highest prevalence of T. gondii antibodies were young adults (32%), following by adults (27%) and fawns (13%). Only one serum sample (8%) from a newborn fawn was positive in the serological tests. The convenience of the Dot-ELISA test is obvious when compared with other serological tests for both laboratory or field surveys, mainly due to its features of practicability and reagent stability.

Anti-Toxoplasma gondii immunoglobulins A and G in human saliva and serum

Paired human saliva and serum samples from 60 individuals were tested for specific IgA and IgG antibodies to Toxoplasma gondii. The study in both fluids was carried out by indirect immunoenzymatic assay (ELISA). Saline antigenic extract of T. gondii was used to coat plastic surfaces upon which the samples were then incubated; monospecific conjugates of anti-IgA and anti-IgG-peroxidase were then incubated with the samples after a washing procedure to separate the unbound antibodies. The enzymatic activity was measured and the results expressed in terms of ELISA index. Toxoplasma-specific IgG antibodies were detected in 43 of the serum samples (71.7%) and in 12 of the saliva samples (20.0%) whereas Toxoplasma-specific IgA antibodies were detected in 18 of the serum samples (30.0%) and in 12 of the saliva samples (20.0%). No association was observed when the Toxoplasma-specific IgG reactive and non-reactive serum samples were compared with the reactive and non-reactive saliva samples for this class of immunoglobulin. On the other hand, a significant association was observed when the Toxoplasma-specific IgA reactive and non-reactive serum samples were compared with the reactive and non-reactive saliva for this type of antibody. In conclusion, our results show that the detection of salivary IgA reflects the serum level of this isotype but salivary IgG does not. Moreover, the isolated detection of salivary IgG may not contribute to epidemiological studies of chronic toxoplasmic infections.

Total and specific anti-Trypanosoma cruzi immunoglobulin E in pericardial fluid samples from patients with chronic Chagas disease

Levels of total and specific anti-Trypanosoma cruzi immunoglobulin E (IgE) were determined by immunoenzymatic assay among 101 samples of pericardial fluid from patients who had died in one trypanosomiasis endemic area in central Brazil. These samples were divided into 6 groups. Group I, 17 samples from patients with the cardiac form of Chagas disease; group II, 11 samples from patients with the digestive form of Chagas disease, presenting megaoesophagus and/or megacolon; group III, 41 samples from patients with the indeterminate form of Chagas disease; group IV, 4 samples from patients with both cardiac and digestive forms of Chagas disease; group V, 5 samples from patients who suddenly died and were seropositive for T. cruzi antibodies; group VI, 23 samples, used as a control group, which came from patients seronegative for T. cruzi antibodies. Significantly high levels of total IgE were observed in groups I, II, III, IV and V when compared with group VI (mean concentrations 708-1157 iu/mL compared with 394 iu/mL). In groups I-V, 32 samples (41%) had specific anti-T. cruzi IgE antibodies. The individual percentage positivity rates in these groups were 64.7% (group I), 45.4% (group II), 34.1% (group III), nil (group IV), and 40.0% (group V). A significant correlation between total IgE and specific anti-T. cruzi IgE was observed only in the samples from patients with the cardiac form of Chagas disease (group I).

Analysis of aqueous humor in ocular toxoplasmosis: detection of low avidity IgG specific to Toxoplasma gondii

Using a modified enzyme-linked immunosorbent assay that included dissociation of antigen antibody complexes with 6M urea solution, we analyzed the avidity of Toxoplasma-specific IgG in aqueous humor and serum samples from 24 patients with toxoplasmic chorioretinitis. As a control, we studied aqueous humor and serum samples from 14 cataract patients without history of uveitis and serum samples from 10 patients with recent primary systemic toxoplasmic infection without ocular lesions. IgG avidity was markedly lower in aqueous humor samples from patients with toxoplasmic chorioretinitis than in serum samples, despite those samples presenting higher levels of Toxoplasma-specific IgG than in serum samples. The detection of the low-avidity Toxoplasma-specific antibodies can offer a valuable aid to make a specific etiologic diagnosis and perhaps contribute to understand the pathogenic mechanisms of ocular toxoplasmosis.

The single-pass cerebral extraction and capillary permeability-surface area product of several putative cerebral blood flow imaging agents

We have determined cerebral blood flow (CBF) and the single-pass cerebral extraction (E) of several putative agents for external imaging of CBF. Simultaneous measurements of blood flow and extraction were performed in 106 rats. For all agents, comparison of linear and exponential regressions of E on CBF indicates that this relationship can be described as linear over the range of flows studied. Analysis of covariance indicates that the extraction of 123I-IMP, 67Cu-PTSM and 99mTc-HMPAO is higher than that of 99mTc-Cl(DMG)3(2MP) and 99mTc-ECD, particularly at flows above the normal range. Accordingly, for 123I-IMP, 67Cu-PTSM and 99mTc-HMPAO, the slope of the linear regression equation for the relationship between brain capillary permeability surface area product (PS) and CBF is higher than that for 99mTc-Cl(DMG)(3)2MP and 99mTc-ECD. PS varies as a linear function of CBF over the range of flows studied. At a CBF level that corresponds to normal regional CBF for human cortex, 0.5 ml/g/min, all the agents have a single-pass extraction of approximately 70% or greater. While all the agents detected changes in CBF in the normal to ischemic range, at higher flows 123I-IMP, 67Cu-PTSM and 99mTc-HMPAO showed substantially greater fidelity to true CBF than 99mTc-Cl(DMG)(3)2MP and 99mTc-ECD.