Critical mercury concentration in tropical soils: Impact on plants and soil biological attributes.

Mercury is a toxic element that becomes a problem when present at high concentrations in soils. Mercury toxicity in soils varies depending on chemical species, concentration, exposure routes, and organism vulnerability. There is little information regarding the toxicity of Hg in tropical soils, especially for establishing safe levels of this pollutant. The purpose of this study was to investigate Hg concentrations in two tropical soils and their effect on oats and common beans, as well as on soil biological attributes. The experiment was carried out in a greenhouse, following ISO 11.269-2 and OECD-208 guidelines. Oat and common bean were cultivated in a Typic Hapludox (TyHpx) and Rhodic Acrudox (RhAcx) contaminated with HgCl2 at the following concentrations: 0, 2.5, 5.0, 10.0, 20.0, 40.0, and 80.0 mg of Hg kg-1 of dry soil. The biological variables analyzed were seedling emergence, vegetative growth, chlorophyll content (SPAD index), gas exchange (photosynthetic rate, internal CO2 concentration, transpiration rate, and stomatal conductance), and Hg concentration and accumulation in shoot dry matter. Microbial biomass carbon, soil basal respiration, and metabolic quotient (qCO2) were also analyzed. Due to the sorptive characteristics of TyHpx, it had higher Hg concentrations than RhAcx. Mercury showed toxic effects on both oat and common bean species. However, common bean was affected only at concentrations higher than 20 mg kg-1. The microbial community showed high sensitivity to soil Hg concentrations, but external factors, such as the plant species cultivated, influenced the sensitivity of the community. The microbiota was most sensitive in pots with common bean, and this effect was more pronounced at low clay and low organic matter contents (TyHpx). In this study, the concentration of 0.36 mg kg-1 was critical for Hg in these soils, based on its deleterious effects on oat and common bean and on biological soil attributes.

Testicular thermoregulation, scrotal surface temperature patterns and semen quality of water buffalo bulls reared in a tropical climate.

This study evaluated the capacity of thermoregulation and its consequences on the scrotal surface temperature patterns and semen quality of buffalo bulls raised in a wet tropical climate. Eleven water buffaloes were evaluated in the rainiest, in the transitional and in the less rainy season. Air temperature and humidity were consistently high, but the animals did not show thermal stress in any season. The scrotal temperature gradient of buffalo bulls using infrared thermography was described, and three parallel and decreasing thermal bands were characterised. Sperm quality (n = 176 ejaculates) was maintained in normal parameters over the periods. Pearson's coefficients showed that sperm volume and progressive motility were negatively correlated with ocular globe, epididymal tail and minimum scrotal temperatures (p < .01). Sperm membrane integrity was negatively influenced by increases in epididymal tail and minimum scrotal temperatures (p < .01). Ocular globe temperature also showed positive correlation with rectal, spermatic cord, and epididymal tail temperatures (p < .01). Therefore, even under high temperature and humidity, the thermoregulatory system was effective in preventing heat stress and the normality of scrotal surface temperatures, spermatogenesis and sperm maturation were maintained.

Carbon-covered mesoporous silica and its application in Rhodamine B adsorption.

Modified versions of MCM-41 and SBA-15 were obtained from sucrose by carbon deposition. The ability of the resulting materials, MCM-41 CC and SBA-15 CC, to remove Rhodamine B from aqueous solutions was evaluated. TG/DTG, XRD, Nitrogen Adsorption (BET), and SEM were used to characterize the materials. Adsorption was investigated by finite bath studies. To characterize the adsorption behavior and mechanism, kinetics and equilibrium were assessed. MCM-41 CC provided the best adsorption results: adsorptive capacity of 11.91 mg of dye/g of material and 91.95% w/v dye removal (C0 = 50 mg L-1). The sucrose particles interacted well, to result in improved area and micropore volume. Hence, carbon deposition can afford materials with increased adsorptive capacity depending on the sieve employed during their preparation.

Efeitos do trimetilaminoetano (TES) e ringer lactato em sêmen de macacos-aranha mantidos em cativeiro ( Ateles paniscus e A. marginatus) / Effects of TES and a ringer-lactato diluent in semen from captive spider monkeys (Ateles paniscus e A. marginatus)

The performances of the diluents TES and CEBRAN II were compared as cryopreservatives of semen from non human primates of the genus Ateles. The experiment was carried out using one Ateles marginatus and two Ateles paniscus specimens, males and adults, maintained in the same captivity conditions at the National Center of Primates (CENP-SVS/MS). The animals were subjected to clinical and andrological examinations - testicular biometry - before the semen collection by eletroejaculation. Evaluations of motility and forward movement in the fresh semen were made. Semen were made dilution was made with the diluents TES and CEBRAN II. The ejaculates were diluted with the diluents (2:1proportion), packed in 0.25mL plastic straws and cryopreserved in liquid nitrogen. After thawing, the packed ejaculates were appraised in thermo resistance test (TTR). The averages of volume and concentration were, respectively, 1.94mL (0.83) and 3,020,000 sptz/mL (275.97). The pH 8 and seminal coagulation were observed in all samples. The results suggest that the TES diluent presents better efficiency in the preservation of Ateles semen than CEBRAN II.

Highly elevated levels of perfluorooctane sulfonate and other perfluorinated acids found in biota and surface water downstream of an international airport, Hamilton, Ontario, Canada.

Per- and poly-fluorinated compounds (PFCs), which include perfluorinated carboxylates (PFCAs) and sulfonates (PFSAs) and various precursors, are used in a wide variety of industrial, commercial and domestic products. This includes aqueous film forming foam (AFFF), which is used by military and commercial airports as fire suppressants. In a preliminary assessment prior to this study, very high concentrations (>1 ppm wet weight) of the PFSA, perfluorooctane sulfonate (PFOS), were discovered in the plasma of snapping turtles (Chelydra serpentina) collected in 2008 from Lake Niapenco in southern Ontario, Canada. We presently report on a suite of C(6) to C(15) PFCAs, C(4), C(6), C(8) and C(10) PFSAs, several PFC precursors (e.g. perfluorooctane sulfonamide, PFOSA), and a cyclic perfluorinated acid used in aircraft hydraulic fluid, perfluoroethylcyclohexane sulfonate (PFECHS) in surface water from the Welland River and Lake Niapenco, downstream of the John C. Munro International Airport, Hamilton, Ontario, Canada. Amphipods, shrimp, and water were sampled from the Welland River and Lake Niapenco, as well as local references. The same suite of PFCs in turtle plasma from Lake Niapenco was compared to those from other southern Ontario sites. PFOS dominated the sum PFCs in all substrates (e.g., >99% in plasma of turtles downstream the Hamilton Airport, and 72.1 to 94.1% at all other sites). PFOS averaged 2223(±247.1SE) ng/g in turtle plasma from Lake Niapenco, and ranged from 9.0 to 171.4 elsewhere. Mean PFOS in amphipods and in water were 518.1(±83.8)ng/g and 130.3(±43.6) ng/L downstream of the airport, and 19.1(±2.7) ng/g and 6.8(±0.5) ng/L at reference sites, respectively. Concentrations of selected PFCs declined with distance downstream from the airport. Although there was no known spill event or publicly reported use of AFFF associated with a fire event at the Hamilton airport, the airport is a likely major source of PFC contamination in the Welland River.

Transporte de oócitos bovinos em meio de maturação por diferentes períodos de tempo sem controle da atmosfera gasosa / Transport of bovine oocytes in maturation medium for different periods of time whithout controlled gaseous atmosphere

Avaliou-se a viabilidade do transporte de oócitos em meio quimicamente definido, e analisou-se a necessidade da adição ou não de hormônios neste meio. Os oócitos do grupo-controle (0h) foram maturados por 24h em estufa de CO2, e os dos grupos experimentais foram transportados em incubadora portátil. No experimento I, as taxas de clivagem foram similares (P>0,05) para os grupos 0h (59,7 por cento), 3h (53,5 por cento) e 9h (48,8 por cento), e houve redução nos grupos 6h (46,1 por cento) e 12h (43,8 por cento). Essas taxas foram semelhantes entre os grupos 3h, 6h, 9h e 12h. A produção de blastocistos não foi diferente (P>0,05) para os grupos 0h (38,0 por cento), 3h (32,3 por cento), 6h (27,3 por cento) e 9h (24,8 por cento), e houve redução no grupo 12h (18,9 por cento). Essas taxas foram semelhantes entre os grupos 6h, 9h e 12h. No experimento II, não houve diferença (P>0,05) entre as taxas de clivagem para os grupos 0h (71,4 por cento), 3h (70,3 por cento), 6h (56,0 por cento) com hormônios, e os grupos 3h (64,8 por cento) e 6h (54,1 por cento) sem hormônios. A produção de blastocistos foi similar (P>0,05) para os grupos 0h (46,1 por cento), 3h com hormônios (45,8 por cento) e 3h sem hormônios (41,1 por cento), porém houve redução nos grupos 6h com hormônios (35,5 por cento) e 6h sem hormônios (33,5 por cento). Essas taxas foram semelhantes entre os grupos 3h sem hormônios e 6h com e sem hormônios. Estes resultados indicam que é possível otransporte de oócitos bovinos por um período de até nove horas, e que a adição de hormônios neste meio não influencia os índices de clivagem e de blastocistos.

The viability of the transport of the bovine oocytes was evaluated in chemically defined medium and the need for the addition or not of hormones in this medium was analyzed. The oocytes in the control group (0h) were matured for 24h in CO2 incubator, and in experimental groups they were transported in portable incubator. In experiment I, the cleavage rates were similar (P>0.05) to the groups 0h (59.7 percent), 3h (53.5 percent), and 9h (48.8 percent), but they decreased in groups 6h (46.1 percent) and 12h (43.8 percent), however, these rates were similar among the groups 3h, 6h, 9h, and 12h. The production of blastocysts was not different (P>0.05) for groups 0h (38.0 percent), 3h (32.3 percent), 6h (27.3 percent), and 9h (24.8 percent), but there was a reduction in the 12h group (18.9 percent). These rates were similar among the groups 6h, 9h and 12h. In experiment II, no significant difference (P>0.05) was observed among the rates of cleavage for the groups 0h (71.4 percent), 3h with (70.3 percent) and without hormones (64.8 percent), and 6h with (56.0 percent) and without hormones (54.1 percent). The production of blastocysts was similar (P>0.05) for groups 0h (46.1 percent) and 3h with (45.8 percent) and without hormones (41.1 percent), but decreased in groups 6h with (35.5 percent) and without hormones (33.5 percent). These rates were similar among the groups 3h without, 6h with and without hormones. These results indicate the possibility of the transport of bovine oocytes up to 9h, and the addition of hormones in this medium does not influence the rates of cleavage and blastocysts.

Efeito do estradiol e da progesterona no desenvolvimento e na qualidade de embriões bovinos produzidos in vitro / Effect of estradiol and progesterone on development and quality of bovine embryos produced in vitro

Avaliaram-se o desenvolvimento e a qualidade de embriões bovinos, cocultivados com células epiteliais do oviduto bovino (CEOBs) expostas ou não ao estradiol e à progesterona. Os ovócitos foram maturados in vitro por 24h e, então, fertilizados utilizando-se sêmen congelado, em estufa de CO2 a 5 por cento e 38,5ºC. As CEOBs foram cultivadas em TCM-199 com ou sem estradiol (E2) (24 horas), nas mesmas condições da maturação e fertilização in vitro (MIV e FIV), e, em seguida, adicionadas aos diferentes grupos em CR2 com ou sem progesterona (P4) (G1=P4+E2); (G2=E2); (G3=P4) e (G4=controle). Após 18h da FIV, as células foram cultivadas nos diferentes sistemas. Nenhuma diferença (P>0,05) foi observada nas taxas de clivagem entre G1, G2 e G4 (53,5 por cento; 56,3 por cento; 51,7 por cento) e nos padrões de blastocistos (BLs) (29,3 por cento; 31,2 por cento, 28,7 por cento). Índices menores (P<0,05) foram obtidos no G3 para ambas as variáveis (34,5 por cento; 16,4 por cento). G1 e G2 apresentaram taxas de eclosão maiores (P<0,05) que os outros grupos (23,3 por cento; 23,2 por cento), sendo G4 (19,3 por cento) diferente de G3 (16,1 por cento). Em G1, G2 e G3, o número de células nos BLs aumentou 125,9; 128,4 e 123,6, respectivamente (P<0,05), em relação ao G4 (112,5). Conclui-se que o tratamento das CEOBs com o E2, nas primeiras 24 horas de cultivo, pode ser usado isoladamente ou em combinação com a progesterona, a fim de melhorar a qualidade de embriões bovinos produzidos in vitro.

The development and quality of bovine embryos co-cultivated with bovine oviduct epithelial cells (BOEC) supplemented or not with estradiol and progesterone were evaluated. Oocytes were matured and fertilized in vitro (MIV/FIV) (5 percentCO2/38.5ºC). The BOEC were cultivated in TCM-199 with or without estradiol (E2) (24h), in the same conditions of MIV/FIV. Presumptive zygotes were transferred to BOEC in suspension after in vitro maturation and fertilization of bovine oocytes with thawed percoll-selected sperm. The zygotes were cultivated in CR2 medium containing or not progesterone (P4) (G1=P4+E2), (G2=E2), (G3=P4), and (G4=control). No significant differences (P>0.05) were found in the cleavage rates among G1, G2, and G4 (53.5 percent, 56.3 percent, and 51.7 percent) as well as in relation to the blastocystis (BL) rates (29.3 percent, 31.2 percent, and 28.7 percent). However, significant differences (P<0.05) were observed in the G3 for both variables (34.5 percent and 16.4 percent). G1 and G2 showed hatching rates higher (P<0.05) than the other groups (23.3 percent; 23.2 percent), being G4 (19.3 percent) different from G3 (16.1 percent) (P<0.01). In the groups G1, G2, and G3, the total cell number of the BL increased (125.9, 128.4, and 123.6) (P<0.05) compared to G4 (112.5). These results demonstrate that the treatment of the BOEC with estradiol in first the 24 hours of culture can be used separately or in combination with the progesterone to improve the quality of bovine embryos produced in vitro.

Genotype and sex effects on carcass and meat quality of suckling kids protected by the PGI "Cabrito de Barroso".

Carcass composition and meat quality traits were evaluated in 55 suckling kids (27 males and 28 females) from Serrana (S), Bravia (B) and Serrana×Bravia (S×B) crossbred genotypes. Kids were slaughtered at 8-11kg of live weight according to "Cabrito de Barroso-PGI" specifications and carcasses' left sides were totally dissected. Dressing percentage (based on ELW) did not vary between genotypes and sexes. Genotype B carcasses have better conformation, expressed in higher compactness index and muscle/bone ratio. Sex had no effect on the composition of dissected carcass but females deposited more internal fat than males. S genotype had significantly less muscle content and higher dissectible fat compared to B and S×B genotypes, suggesting differences in maturity stages. The carcass' bone content (20.4-21.4%) did not differ significantly between genotypes. The longissimus thoracis et lumborum (LTL) and gluteobiceps (GB) muscles were used for meat quality determinations. Genotype had a significant effect on meat traits and fatty acid composition of the analysed muscles: B genotype and LTL muscle showed lower final pH, S×B genotype had darker and more red muscles, GB muscle had a higher shear force value and lower collagen solubility. Few sex effects were observed on meat quality traits as well as on fatty acid composition. Average percentage of desirable fatty acids in kids was superior to 60% with male S genotype displaying a lower value. Genotypes B and B×S, males and GB muscle had more favorable PUFA:SFA ratios.

Clinical significance of a negative loop electrosurgical excision procedure, conization and hysterectomy for cervical intraepithelial neoplasia.

PURPOSE OF INVESTIGATION: The absence of cervical intraepithelial neoplasia (CIN) in a loop electrosurgical excision procedure (LEEP), cold-knife conization and hysterectomy for treatment of CIN is an occasional finding of uncertain clinical significance. The aim of this study was to estimate the frequency of a negative procedure and its relationship to disease recurrence. METHODS: A retrospective study was conducted on 263 specimens from women submitted to the LEEP (n = 142), conization (n = 101) or hysterectomy (n = 20) due to CIN. RESULTS: The frequency of negative conization, LEEP and hysterectomy were, respectively, 15.5%, 19.8% and 25%. Recurrence occurred from 16 to 44 (median = 42) months in women with negative surgical specimens (LEEP or cold knife conization), and after five to 31 (median = 20) months after histological findings of CIN in surgical specimens, respectively, 7.1% and 11.2%. CONCLUSION: The absence of CIN in those procedures of biopsy-confirmed CIN is a not an uncommon finding. Patients with positive or negative specimens should be carefully followed.

Geographic distribution of hepatitis C virus genotypes in Brazil.

Brazil is a country of continental dimension with a population of different ethnic backgrounds. Thus, a wide variation in the frequencies of hepatitis C virus (HCV) genotypes is expected to occur. To address this point, 1,688 sequential samples from chronic HCV patients were analyzed. HCV-RNA was amplified by the RT-PCR from blood samples collected from 1995 to 2000 at different laboratories located in different cities from all Brazilian States. Samples were collected in tubes containing a gel separator, centrifuged in the site of collection and sent by express mail in a refrigerated container to Laboratório Bioquímico Jardim Paulista, São Paulo, SP, Brazil. HCV-RNA was extracted from serum and submitted to RT and nested PCR using standard procedures. Nested PCR products were submitted to cycle sequencing reactions without prior purification. Sequences were analyzed for genotype determination and the following frequencies were found: 64.9% (1,095) for genotype 1, 4.6% (78) for genotype 2, 30.2% (510) for genotype 3, 0.2% (3) for genotype 4, and 0.1% (2) for genotype 5. The frequencies of HCV genotypes were statistically different among Brazilian regions (P = 0.00017). In all regions, genotype 1 was the most frequent (51.7 to 74.1%), reaching the highest value in the North; genotype 2 was more prevalent in the Center-West region (11.4%), especially in Mato Grosso State (25.8%), while genotype 3 was more common in the South (43.2%). Genotypes 4 and 5 were rarely found and only in the Southeast, in São Paulo State. The present data indicate the need for careful epidemiological surveys throughout Brazil since knowing the frequency and distribution of the genotypes would provide key information for understanding the spread of HCV.

Geographic distribution of hepatitis C virus genotypes in Brazil

Brazil is a country of continental dimension with a population of different ethnic backgrounds. Thus, a wide variation in the frequencies of hepatitis C virus (HCV) genotypes is expected to occur. To address this point, 1,688 sequential samples from chronic HCV patients were analyzed. HCV-RNA was amplified by the RT-PCR from blood samples collected from 1995 to 2000 at different laboratories located in different cities from all Brazilian States. Samples were collected in tubes containing a gel separator, centrifuged in the site of collection and sent by express mail in a refrigerated container to Laboratório Bioquímico Jardim Paulista, São Paulo, SP, Brazil. HCV- RNA was extracted from serum and submitted to RT and nested PCR using standard procedures. Nested PCR products were submitted to cycle sequencing reactions without prior purification. Sequences were analyzed for genotype determination and the following frequencies were found: 64.9 percent (1,095) for genotype 1, 4.6 percent (78) for genotype 2, 30.2 percent (510) for genotype 3, 0.2 percent (3) for genotype 4, and 0.1 percent (2) for genotype 5. The frequencies of HCV genotypes were statistically different among Brazilian regions (P = 0.00017). In all regions, genotype 1 was the most frequent (51.7 to 74.1 percent), reaching the highest value in the North; genotype 2 was more prevalent in the Center-West region (11.4 percent), especially in Mato Grosso State (25.8 percent), while genotype 3 was more common in the South (43.2 percent). Genotypes 4 and 5 were rarely found and only in the Southeast, in São Paulo State. The present data indicate the need for careful epidemiological surveys throughout Brazil since knowing the frequency and distribution of the genotypes would provide key information for understanding the spread of HCV.

c-KIT and PDGFRA in breast phyllodes tumours: overexpression without mutations?

AIM: To study the immunoexpression and mutational status of c-KIT and PDGFRA in a series of benign and malignant phyllodes tumours of the breast. MATERIAL/METHODS: Nineteen phyllodes tumours (13 benign and six malignant) were analysed by immunohistochemistry for the expression of c-KIT and PDGFRA. Direct sequencing of exons 9, 11, 13, and 17 of the c-KIT gene and exons 12 and 18 of PDGFRA was performed to check the mutational status of these two genes. RESULTS: c-KIT expression was found in 12 of the 19 cases (six of the 13 benign cases and all six malignant ones) and PDGFRA expression was seen in two of the 19 cases (one benign and one malignant case); the 2415 C>T alteration in exon 17 of the c-KIT gene was found in two cases (both benign); the intronic insertion IVS17-50insT and the 2866 G>T alteration in the coding region of exon 18 of the PDGFRA gene were also found in two cases (one malignant and one benign). However, the activating mutations described for these genes in gastrointestinal stromal tumours were not present. CONCLUSION: c-KIT expression is a frequent finding in phyllodes tumours, particularly in malignant cases; however, no activating mutations similar to those described for gastrointestinal stromal tumours were found. The PDGFRA does not seem to be an alternative pathway to tumour development in phyllodes tumours because neither expression nor activating mutations were noteworthy.

[Nursing in mental health in the context of psychosocial rehabilitation and interdisciplinarity]. / Enfermagem em saúde mental no contexto da reabilitação psicossocial e da interdisciplinaridade.

The objective of the present work is to reflect on concepts of psychosocial rehabilitation and interdisciplinarity in the field of mental health. This study points out the importance of those themes for the mental health and/or psychiatric nursing knowledge and practice. Based on complex thought and ethic-esthetic paradigm, criticism is made regarding the rational paradigm. It also aims at building knowledge that can stimulate reflection, investigation, curiosity, questioning of "certainty" and the acceptance of multiple competitive narratives. Psychosocial rehabilitation is understood as a conception, not as a technique. Its is a process which enables the user to establish social and affectionate relationships in different contexts: at home, at work and society. Interdisciplinarity is the capacity of converging different specialized knowledge on the construction of one text. It was observed that the discussion of these themes allows the nursing professionals to understand their practices and knowledge on a utopian, ethical and esthetic dimension.

Low dose of orally administered antigen down-regulates the T helper type 2-response in a murine model of dust mite hypersensitivity.

One of the main goals of immunotherapy of allergic diseases is the down-regulation of the type I hypersensitivity reaction. We investigated in this study the effect of oral administration of varying doses (0.25, 1.0, 4.0 and 10 mg) of dust mite extract (Dermatophagoides pteronyssinus, Dp) in sensitized A/Sn mice. A marked decrease of the allergen-specific immunoglobulin E (IgE) response was observed with all antigen doses. The mice orally tolerized with low Dp dose (0.25 mg) had a significant decrease in the total serum IgE and in the immunoglobulin G1 (IgG1), IgG2a and IgG2b antibody levels. The higher Dp dose (10.0 mg), however, enhanced the IgG1 antibody response, suggesting the stimulation of a pre-existing immune response of the sensitized animals. Animals fed with the low Dp dose had a significant decrease in the frequency of interleukin-4 (IL-4) secreting cells. These animals also showed a significant decrease in the frequency of Dp-specific IgE- and IgG1-positive plasma cells. Our data suggest that feeding dust mite extract to Dp-sensitized mice down-regulates the development of type I hypersensitivity, by inhibition of the T helper 2 response.

High prevalence of GB virus C in Brazil and molecular evidence for intrafamilial transmission.

The prevalence of GB virus C (GBV-C) in candidate Brazilian blood donors with normal and elevated alanine aminotransferase levels was found to be 5.2% (5 of 95) and 6.5% (5 of 76), respectively. Among Brazilian patients, GBV-C was found in 9.5% (13 of 137) of cases of hepatitis not caused by hepatitis A virus (HAV), HBV, HCV, HDV, or HEV (non-A-E hepatitis) and in 18.2% (8 of 44) of individuals infected with HCV. Molecular characterization of GBV-C by partial sequencing of the NS3 region showed clustering between members of a single family, implying intrafamilial transmission. In conclusion, these results together suggest that contagion mechanisms which facilitate intrafamilial transmission of GBV-C may partially explain the high prevalence of viremic carriers worldwide.

Pesquisando o pesquisado: um estudo sobre a compreensao de pessoas que serviram como sujeitos de investigacao, a respeito da propria pesquisa

Ciencia e pesquisa sao sinonimos. Nao ha duvida quanto a importancia da discussao acerca dos aspectos eticos relacionados ao trabalho de pesquisa. As pessoas acreditam na fundamental importancia da pesquisa, bem como na necessidade de cooperar como sujeitos. Paralelo a isso, estes sujeitos demonstram interesse em conhecer os resultados da pesquisa nas quais participam. Este interesse e a credibilidade dos sujeitos e um importante aspecto a ser considerado em qualquer delineamento de pesquisa.

Oral tolerance induced to house dust mite extract in naive and sensitized mice: evaluation of immunoglobulin G anti-immunoglobulin E autoantibodies and IgG-IgE complexes.

We investigated the effect on specific antibody response of naive and sensitized mice orally administrated with low (0.25 mg) or high (10.0 mg) doses of Dermatophagoides pteronyssinus (Dp) extract. We also examined the effect of oral administration of Dp on the production of autoantibodies to immunoglobulin G (IgG) and immunoglobulin E (IgE). Naive and sensitized mice both showed a marked down-regulation of IgE antibody production, regardless of the dose of Dp. We also detected an inhibitory effect of the total IgE levels and the allergen-specific IgG1, IgG2a and IgG2b antibody response in sensitized mice given the low dose of Dp. In contrast, high doses of Dp stimulated IgG1 antibody production in both naive and sensitized animals. In addition, the oral tolerance induction protocol stimulated anti-F(ab')2gamma and anti-Fcgamma autoantibody production. Evaluation of IgG anti-IgE autoantibodies by a direct enzyme immunoassay (EIA) revealed the presence of these autoantibodies, predominantly of the IgG1 isotype, specifically in those animals fed with the high dose. In contrast, IgG-IgE complexes, determined by EIA using immobilized anti-IgE antibodies, were detected mainly in sera of control animals. The autoantibody anti-IgE specificity was tested against IgE-TNP and IgE-DANSYL murine proteins and revealed different inhibition profiles, suggesting the action of heterogeneous subpopulations of autoantibodies. Taken together, our results show that the oral tolerance protocol with Dp was able to modulate the production of allergen-specific IgE antibodies in both naive and sensitized animals. In addition, we suggest that anti-IgE autoantibodies participate in the modulation of allergic response triggered by oral tolerance protocols.

[Fatal liver necrosis due to allopurinol]. / Necrose hepática fatal por alopurinol.

Allopurinol hypersensitivity syndrome (AHS) is a severe reaction which is potentially lethal. Exanthematous rash, fever, eosinophilia, and other severe reactions such as toxic epidermal necrolysis, acute vasculitis, and severe hepatic and renal dysfunctions are manifestations of this syndrome. The authors report a case of lethal massive hepatic necrosis due to allopurinol in a patient with the asymptomatic hyperuricemia. They also describe the risk factors most frequently associated with the development of AHS and the strategy for its prevention and consequent reduction of the mortality associated with this syndrome.