Efeitos tóxicos dos sedimentos do estuário do rio Capibaribe em embriões de zebrafish (Danio rerio) / Toxic effects of sediments of the Capibaribe estuary on zebrafish embryos (Danio rerio)

O presente estudo utilizou embriões de Danio rerio expostos aos elutriatos dos sedimentos estuarinos do rio Capibaribe, dos períodos chuvoso e seco, e analisou os efeitos letais, teratogênicos, bem como a frequência cardíaca. Os testes de toxicidade com os embriões seguiram as diretrizes da OECD 236. Mediante os resultados obtidos, a frequência cardíaca e a teratogenicidade foram os efeitos mais observados nos animais quando submetidos às amostras. Entre os efeitos teratogênicos, o retardo geral no desenvolvimento dos embriões foi o mais frequente durante as análises. Tais efeitos tóxicos se modificaram entre os pontos e entre os períodos de coleta. Essa variação de toxicidade pode estar relacionada à diversidade de atividades realizadas no entorno desse estuário, a influência do regime de chuvas, marés e correntes, indicando que a análise dos efeitos subletais e da teratogenicidade em embriões de D. rerio constitui bom parâmetro para avaliações de toxicidade de amostras ambientais.(AU)

The present study used Danio rerio embryos exposed to the elutriates of the estuarine sediments of the Rio Capibaribe, from the rainy and dry periods, where the lethal effects, teratogenic and heart rate were analyzed. Embryotoxicity tests followed the guidelines of OECD 236. Based on the results obtained, heart rate and teratogenicity demonstrated higher sensitivity to the samples. Among the teratogenic effects, the general delay in embryo development was the most frequent effect during the analyzes. These toxic effects changed between the points and between the collection periods. This variation of toxicity may be related to the diversity of activities carried out around this estuary, the influence of rainfall, tides, and currents, indicating the analysis of sublethal effects and teratogenicity in the D. rerio embryos are useful parameters for toxic evaluation of environmental samples.(AU)

Karyotype diversity and genome size variation in Neotropical Maxillariinae orchids.

Orchidaceae is a widely distributed plant family with very diverse vegetative and floral morphology, and such variability is also reflected in their karyotypes. However, since only a low proportion of Orchidaceae has been analysed for chromosome data, greater diversity may await to be unveiled. Here we analyse both genome size (GS) and karyotype in two subtribes recently included in the broadened Maxillariinea to detect how much chromosome and GS variation there is in these groups and to evaluate which genome rearrangements are involved in the species evolution. To do so, the GS (14 species), the karyotype - based on chromosome number, heterochromatic banding and 5S and 45S rDNA localisation (18 species) - was characterised and analysed along with published data using phylogenetic approaches. The GS presented a high phylogenetic correlation and it was related to morphological groups in Bifrenaria (larger plants - higher GS). The two largest GS found among genera were caused by different mechanisms: polyploidy in Bifrenaria tyrianthina and accumulation of repetitive DNA in Scuticaria hadwenii. The chromosome number variability was caused mainly through descending dysploidy, and x=20 was estimated as the base chromosome number. Combining GS and karyotype data with molecular phylogeny, our data provide a more complete scenario of the karyotype evolution in Maxillariinae orchids, allowing us to suggest, besides dysploidy, that inversions and transposable elements as two mechanisms involved in the karyotype evolution. Such karyotype modifications could be associated with niche changes that occurred during species evolution.

Salivary biomarkers, vital signs and behaviour of pre-school children during their first dental visit.

AIM: Anxiety may influence dental treatment unfavourably, thus evaluation of the psychophysiological reactions of the child may reduce its negative effects. This study aimed to evaluate and correlate the levels of cortisol and alpha-amylase, vital signs and behaviour of children during their first dental visit. METHODS: Study sample consisted of 32 children (11 male and 21 female patients) aged between 4 and 6 years, who would go to the dentist for the first time, with no pain or chronic illness, and without the use of medication. Three saliva samples were collected: before, immediately after and 20 minutes after the dental procedure (dental prophylaxis). STATISTICS: Data were analysed using Student's t test and Pearson's correlation test (p = 0.05). RESULTS: In the comparison of the levels of alpha-amylase, the heart rate and blood pressure were higher after the dental visit and the levels of salivary cortisol were significantly higher before. There was no statistically significant difference in the correlation between the Frankl Behaviour Rating Scale and the levels of cortisol and alpha-amylase, but the results showed that the levels of these two salivary biomarkers increased gradually as the child had a less cooperative behaviour. CONCLUSION The sample revealed that the first dental visit generated anxiety, which was manifested through physiological and behavioural alterations.

Determination of glyphosate in water samples by IC.

Agricultural development and its associated impacts on the environment are resulting in increasingly restrictive guidelines and legislation concerning the use of chemicals in agro-ecosystems. The herbicide glyphosate is widely used for weed control in both cultivated and uncultivated areas and is considered to show low toxicity to mammals. It is highly water-soluble, and its monitoring in surface, underground, and potable waters is recommended by the United States Environmental Protection Agency. This work presents a method for the inclusion of glyphosate determination within routine anion analysis using ion chromatography in water sampler without any kind of extraction, clean-up, or preconcentration step. The equipment used was a Dionex Model ICS-3000 ion chromatograph fitted with a 25-microL loop, Ion Pac AG19 guard and AS19 analytical columns, ASRS-300 (2 mm) suppressor, and conductivity detector. The method showed a linear response to glyphosate between 0.05-0.75 mg/L with a correlation coefficient of 0.999, and a detection limit below the maximum levels permitted by Brazilian legislation. Recoveries in the range 90-105% were achieved in tests using surface, well, potable, and ultrapure water samples.

Assessment of a new lateral flow immunochromatographic (LFIC) assay for the okadaic acid group of toxins using naturally contaminated bivalve shellfish from the Portuguese coast.

A new rapid assay for the okadaic acid group of toxins, based on lateral flow immunochromatographic (LFIC) test strips developed by Jellett Rapid Testing Ltd., was assessed on naturally contaminated bivalves from the Portuguese coast. One prototype was evaluated using samples harvested during 2005, extracted with 80% methanol, followed by dilution with the running buffer of a methanolic extract after alkaline hydrolysis for esters. The second prototype was assessed using samples harvested during 2006, extracted with 100% methanol and, after alkaline hydrolysis, the methanol was evaporated by a nitrogen stream followed by re-suspension with the running buffer. The first prototype failed to detect 20% of samples that were positive by LC-MS in the range 160-480 microg kg(-1), and were classified as negative or trace level by LFIC. The presence of methanol in the extracts made correct detection of toxins more difficult. The second prototype classified as positive all samples above 160 microg kg(-1), as confirmed by LC-MS. However, in the second prototype, matrix effects were a major drawback and led to 45% false positives, particularly for mussels, due to compounds in shellfish extracts interfering with the antibodies and reducing the test line intensity. Extraction with a higher percentage of methanol was thought responsible for these matrix effects. Regarding sample migration, both prototypes needed one hour before reading. In an attempt to speed-up sample preparation, a direct digestion of bivalve tissues with sodium hydroxide was evaluated. Low recoveries for esters were found by LC-MS with this hydrolysis technique compared to conventional hydrolysis of methanolic extracts. While prototype A was not sensitive enough, prototype B had too many false positives to be of use to the shellfish industry or in a monitoring program.

Extraction recoveries and stability of diarrhetic shellfish poisoning (DSP) toxins in naturally contaminated samples.

During the last few years the occurrence of a high percentage of esters of diarrhetic shellfish poisoning (DSP) toxins has been observed in shellfish from the Portuguese coast. Most of the commercial bivalves contain DSP toxins in ester forms, either acyl derivatives of okadaic acid (OA) or of dinophysistoxin-2 (DTX-2). The stability of these toxins in shellfish tissues and in raw methanol extracts was investigated in two different naturally contaminated species, mussel and carpet shell, over a 4-week period. The results for both species revealed that DSP toxins were more stable in tissue than in raw methanol extracts. Losses of DSP toxins were seen in the first 2 weeks and were more than 30%, but after that a period of stabilization was observed. The decrease was due probably from losses of esters of OA and DTX-2, the free toxins were stable over the period studied. The extraction most commonly used for chemical and biochemical assays relied on methanolic extraction with aqueous 80% methanol. In this work we have tested the extraction solvent on the extractability of DSP toxins from several naturally contaminated species. A single dispersive extraction with methanol, with solvent ratios of 70%, 80%, 90% and 100%, were tested. After alkaline hydrolysis of esterified toxins and clean-up with hexane and dichloromethane, the samples were analysed by liquid chromatography-mass spectrometry (LC-MS). The recovery of DSP toxins increased with increasing percentages of methanol up to 90%. A decrease in recovery with 100% methanol was observed probably due to problems during the liquid-liquid partitioning.

Heterogeneous patterns of oligodendroglial differentiation in the forebrain of the opossum Didelphis marsupialis.

The differentiation of oligodendrocytes in the forebrain of the opossum (Didelphis marsupialis) has been studied by the immunohistochemical identification of 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) and by the autoradiographic detection of the uptake of 3H-thymidine. CNPase is expressed early in oligodendroglia somata and fibre sheaths (myelin) in the forebrain and its persistence in the cell bodies is regionally heterogeneous, being ephemeral in cells within the optic pathway, supraoptic decussation, and posterior commissure, of intermediate duration in the mamillo-thalamic fascicle, and stria medullaris, and long-lasting in other diencephalic and in telencephalic tracts. In the cerebral cortex, most CNPase+ cells have small somata and multiple processes (types I and II). CNPase-expressing oligodendrocytes are also regionally heterogeneous in terms of proliferative capability, which could not be detected in forebrain tracts or diencephalon, but has appeared in a small proportion of cells in the neocortical white matter and in the fimbria. Our findings provide additional evidence in favour of the heterogeneity of oligodendrocytes.

CNPase expression in the developing opossum brain stem and cerebellum.

Immunoreactivity to 2',3' cyclic nucleotide 3' phosphohydrolase (CNPase; EC 3.1.4.37) was studied in the developing opossum brain stem and cerebellum. Regional differences were found in oligodendrocytes concerning the time of appearance (early: medical longitudinal fascicle [mlf]; intermediate: inferior colliculus [IC], deep layers of the superior colliculus [SC] and white matter of cerebellar folia; late: optic layer of SC) and duration of immunoreactivity (short: optic layer of SC; intermediate: mlf; long: cerebellar folia, etc). The results suggest that regional heterogeneities in CNPase expression are linked to intrinsic properties of local and afferent axons.

The nature of the use and users of the Midwest Regional Medical Library.

Using a 10 percent random sample of all requests submitted to the Midwest Regional Medical Library during 1968-1969, this study has revealed that physicians constitute the user group making the most requests, that physicians request periodical materials most, that 86.6 percent of materials requested were for periodicals, and that over one-third of materials requested was more than ten years old. It was found that 66.3 percent of requests were filled, that "Pathology, Diseases, and Treatment" was the subject category with the highest percentage of requests, and that this category and Materia Medica were the subjects accounting for over 50 percent of the requests from all users. The subject categories most frequently requested by physicians were found to be the same (Pathology, Diseases, and Treatment and Materia Medica) as for educators and researchers. The most requests from students were in the Materia Medica and "other" subject categories. These findings are significant for drawing up acquisition policy for both the John Crerar Library, which supplies the physical facilities for the MRML, and the borrowing library which submits the requests for users.