Detecção de anticorpo anticoração em camundongos Balb/c imunizados com Streptococcus mutans

Anticorpos para antígenos cardíacos foram analisados por ELISA em 14 soros de camundongos Balb/c hiperimunizados com Streptococcus mutans, inativado pelo formaldeído. Os níveis de anticorpos da classe IgG anticoração e antimiosina elevaram-se significativamente nos animais imunizados quando comparados com os controles, especialmente no grupo A, imunizado e reestimulado com antígenos solúveis de S. mutans. Neste grupo, os resultados do Western Blot mostraram reatividade com miosina cardíaca e uma banda de 35 kDa. A análise histológica dos corações dos animais do grupo B, imunizado e reestimulado com antígenos de superfície do microrganismo, demonstrou a presença de degeneração celular, tipo hidrópica e hialina e focos inflamatórios constituídos de linfócitos e macrófagos no miocárdio e pericárdio. Os resultados deste trabalho reforçam a hipótese da existência de mimetismo antigênico entre tecido cardíaco e S. mutans e chamam a atenção para o risco de desenvolvimento de anticorpos reativos com antígenos próprios induzidos por vacina anticárie com componentes estreptocócicos.

Morfologia e morfometria das papilas mamárias de búfalas

Para este estudo, quinze papilas de fêmeas de búfalos e uma de fêmea bovina foram obtidas no matadouro. Estudos macro e microscópico foram realizados por meio de diferentes técnicas: morfológica, histológica e análises, biométrica, histométrica e mesoscópica. As médias foram: papila cranial direita (PCD) 20,95g; papila caudal direita (PCaD) 21,49g; papila cranial esquerda (PCE) 23,52g; papila caudal esquerda (PCaE) 21,35g. O comprimento médio do ducto papilar, do número de pregas e do comprimento das cisternas papilares foi respectivamente: 0,67/5,5 e 2,17cm para a PCD; 0,62/6,0 e 2,26cm para a PCaD; e para o antímero esquerdo, PCD: 0,71/6,0 e 2,26cm e para PCaD: 0,74/5,7 e 2,57cm. A análise de Pearson revelou uma correlação negativa entre o peso do corpo e o peso da glândula mamária. Foi feita a amostragem das três áreas proximal, média e distal e estas foram fixadas em formaldeído a 10%, seguindo-se a investigação mesoscópica em amostras de espessuras de 10, 20 e 40µm coradas pelas técnicas Azan, F3BA Picrosirus e Weigert - Van Gieson. As análises histológicas e morfométricas foram feitas em amostras de 5µm de espessura o que mostrou que a camada muscular estava disposta em dois arranjos, interna circular e externa longitudinal com epitélio cubóide bi-estratificado. A camada muscular bem desenvolvida estava relacionada com a porção média revelando uma espessura de 22,90mm com uma grande quantidade de tecido conectivo (7,10mm).

Caracterização das áreas hemófagas da placenta bovina

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Instilação de formalina endoluminal como opção terapêutica da retite actínica hemorrágica

A retite actínica hemorrágica é um quadro grave que pode ocorrer em qualquer paciente submetido à radioterapia pélvica, por vezes, sendo necessária terapia transfusional e internação hospitalar. A abordagem terapêutica ainda é bastante controversa. Tanto para o tratamento inicial como para casos refratários, uma das opções é a aplicação de formalina. Este método é barato, facilmente disponível, de simples execução e eficaz no controle da hemorragia. Os autores relatam dois casos de retite actínica hemorrágica de pacientes tratados com instilação de formalina endoluminal, e sua eficácia terapêutica e complicações são discutidas

Efeitos das cardioplegias sangüínea e cristalóide no miocárdio hipertrófico de coelho: avaliação estrutural e ultra-estrutural

OBJETIVO: Comparar e avaliar experimentalmente as alterações estruturais e ultra-estruturais em corações hipertrofiados isolados de coelhos submetidos à parada protegida pela solução de cardioplegia sangüínea e cardioplegia cristalóide. MÉTODO: O estudo compreendeu um grupo controle e dois grupos experimentais. No grupo I, a parada cardíaca foi obtida pela infusão da solução de cardioplegia sangüínea contínua e tépida. No grupo II, a parada cardíaca foi conseguida pela infusão da solução de cardioplegia cristalóide intermitente e fria. No grupo controle, os corações foram submetidos à parada anóxia normotérmica por 45 minutos. Após experimentos, oito amostras da parede lateral do ventrículo esquerdo foram coletadas e fixadas em formaldeído 10% e glutaraldeído 2,5% para análises estrutural e ultra-estrutural. RESULTADOS: Os resultados estruturais e as descrições ultra-estruturais mostraram que os corações submetidos à parada protegida pela cardioplegia sangüínea contínua e tépida (grupo I) estavam mais preservados com alterações celulares menos acentuadas se comparados aos submetidos à parada protegida pela cardioplegia cristalóide intermitente e fria (grupo II) e ao grupo controle. CONCLUSÃO: A cardioplegia sangüínea contínua e tépida (Grupo I) foi mais eficiente na preservação da integridade estrutural e ultra-estrutural do miocárdio, quando comparada à cardioplegia cristalóide intermitente e fria (Grupo II).

Topografia da artéria hepática no fígado de capivara (Hydrochaerus hydrochaeris)

A distribuição dos ramos da artéria hepática, no fígado, foi estudada em 30 fígados de capivara (Hydrochaerus hydrochaeris) mediante injeção arterial com látex natural corado, fixação em formol a 10%, dissecção pela face visceral e esquematização. A lobação do fígado, nestes animais, é semelhante à do suíno, permitindo identificar os lobos lateral direito, medial direito, quadrado, medial esquerdo, lateral esquerdo e caudado (processos caudado e papilar). A artéria hepática divide-se mais freqüentemente (73,3%) nos ramos direito e esquerdo e, em menor número de preparações (26,6%), trifurca-se nos ramos direito, intermédio e esquerdo. Esses vasos alcançam, sob diferentes arranjos, os lobos do fígado.

Properties of chemically modified gelatin films

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Alternative methodologies for the determination of aldehydes by capillary electrophoresis

This paper describes 2 alternative methodologies for the determination of selected aldehydes (formaldehyde, acetaldehyde, propionaldehyde, acrolein, and benzaldehyde) by capillary electrophoresis (CE), the first approach is based on the formation of aldehyde-bisulfite adducts and employs free solution CE with reversed electroosmotic flow and indirect detection, using 10 mmol/L 3,5-dinitrobenzoic acid (pH 4.5) containing 0.2 mmol/L cetyltrimethylammonium bromide as the electrolyte. This novel methodology showed a fairly good sensitivity to concentration, with detection limits with respect to a single aldehyde on the order of 10-40 mu g/L, a reasonable analysis time (separation was achieved in <8 min), and no need for sample manipulation. A second approach was proposed in which 2,4-dinitrophenylhydrazine derivatives of the aldehydes were detected in a micellar electrolyte medium (20 mmol/L berate buffer containing 50 mmol/L sodium dodecyl sulfate and 15 mmol/L beta-cyclodextrin). This latter methodology included a laborious sample preconcentration step and showed much poorer sensitivity (0.5-2 mg/L detection limit, with respect to a single aldehyde), despite the use of sodium chloride to promote sample stacking. Both methodologies proved adequate to evaluate aldehyde levels in vehicular emissions. Samples from the tailpipe exhaust of a passenger car vehicle without a catalytic converter and operated with an ethanol-based fuel were collected and analyzed; the results showed high levels of formaldehyde and acetaldehyde (0.41-6.1 ppm, v/v). The concentrations estimated by the 2 methodologies, which were not in good agreement, suggest the possibility of striking differences in sample collection efficiency, which was not the concern of this work.

Spectrophotometric determination of dipyrone in pharmaceutical preparations by using chromotropic acid

A spectrophotometric method for the determination of dipyrone in pharmaceutical preparations is proposed. This method is based on selective oxidation of dipyrone, in the presence of sulphuric acid, splitting off formaldehyde which reacts with chromotropic acid, also in a sulphuric acid medium, producing a violet-red compound (lambda(max) 575 nm). Beer's law is obeyed in a concentration range of 0.57-5.7 ppm dipyrone with an excellent correlation coefficient (r = 0.9997). The results show a simple, accurate, selective and readily applied method to the determination of dipyrone in pharmaceutical products. The analytical results obtained for these products by the proposed method are in agreement with those of the Brazilian Pharmacopoeia procedure. No interference was observed from common excipients in formulations. Recoveries were within 98.7-101.2%, with standard deviations ranging from 0.2 to 1.7%. (C) 1999 Elsevier B.V. S.A. All rights reserved.

Rapid spot test analysis for the detection of urotropine in pharmaceutical preparations

The widespread falsification and/or adulteration of commercially available pharmaceutical preparations call for reliable methods of drug identification, preferably through selective and rapid sorting color tests that could be undertaken with minimum equipment remote from laboratory facilities. The present work deals with a convenient adaptation and refinement of a spot test devised by Feigl (1966) for urotropine, based on the hydrolytic cleavage of that substance in the presence of sulfuric acid, splitting out formaldehyde which is identified by its color reaction with chromotropic acid. A simple emergency kit was developed for the quick, efficient, inexpensive and easy performance of urotropine tests by semiskilled personnel even in the drugstore laboratory (or office) as well as in a mobile screening operation. It is shown that when the reagents are added according to the recommended sequence a self-heating system is generated, increasing substantially the reactions' rates and the test sensitivity as well. The identification limit found was 25 mug of urotropine, for both solid and liquid samples. The possible interference of 84 substances/materials was investigated. Interference was noted only for methylene blue, acriflavine, Ponceau Red, Bordeaux Red (these dyes are often included in urotropine dosage forms), pyramidone, dipyrone, quinine and tetracycline. A simple procedure for removing most of the interferences is described. Data for 8 commercial dosage forms and results obtained from their analysis are presented.

Sol-gel prepared Pt-modified oxide layers: Synthesis, characterization, and electrocatalytic activity

Thin films of pure RuO2 and IrO2 and mixed Ru0.5Ir0.5O2 oxide modified with Pt particles were prepared by a sol-gel method in the form of thin films of similar to 2 mu m thickness on Ti substrates. Surface morphology of these Pt- modified oxides was examined by scanning electron microscopy and was found to exhibit a significant influence of the chemical composition of the oxide matrix. Element mapping showed homogeneous distribution of the metals. X- ray diffraction and X- ray photoelectron spectroscopy analyses showed that these films consist of metallic Pt particles dispersed in an oxide matrix. Cyclic voltammetry in acid solutions showed that the sol- gel prepared layers have relatively high Pt surface areas. The electrocatalytic activity of these materials toward the anodic oxidation of formaldehyde and methanol was compared in terms of onset potential and current density and was found to follow the sequence: Pt- Ru0.5Ir0.5O2/ Ti > Pt- RuO2/ Ti > Pt- IrO2/ Ti.

Apoptotic bone cells may be engulfed by osteoclasts during alveolar bone resorption in young rats

The alveolar bone is a suitable in vivo physiological model for the study of apoptosis and interactions of bone cells because it undergoes continuous, rapid and intense resorption/remodelling, during a long period of time, to accommodate the growing tooth germs. The intensity of alveolar bone resorption greatly enhances the chances of observing images of the extremely rapid events of apoptosis of bone cells and also of images of interactions between osteoclasts and osteocytes/osteoblasts/bone lining cells. To find such images, we have therefore examined the alveolar bone of young rats using light microscopy, the TUNEL method for apoptosis, and electron microscopy. Fragments of alveolar bone from young rats were fixed in Bouin and formaldehyde for morphology and for the TUNEL method. Glutaraldehyde-formaldehyde fixed specimens were processed for transmission electron microscopy. Results showed TUNEL positive round/ovoid structures on the bone surface and inside osteocytic lacunae. These structures - also stained by hematoxylin - were therefore interpreted, respectively, as osteoblasts/lining cells and osteocytes undergoing apoptosis. Osteoclasts also exhibited TUNEL positive apoptotic bodies inside large vacuoles; the nuclei of osteoclasts, however, were always TUNEL negative. Ultrathin sections revealed typical apoptotic images - round/ovoid bodies with dense crescent-like chromatin - on the bone surface, corresponding therefore to apoptotic osteoblasts/lining cells. Osteocytes also showed images compatible with apoptosis. Large osteoclast vacuoles often contained fragmented cellular material. Our results provide further support for the idea that osteoclasts internalize dying bone cells; we were however, unable to find images of osteoclasts in apoptosis. (C) 2001 Harcourt Publishers Ltd.

Colorimetric determination of ammonia in air using a hanging drop

A simple and sensitive method for determining atmospheric ammonia (NH3), using a hanging drop, is described. A colorimetric sensor is composed of two optical fibers and the source of monochromatic light implemented was a red light emitting diode (LED) (635 nm). Preliminary experiments were carried out in order to optimize the geometry of the sensor. These tests showed that the best signal absorbance was obtained using a 22 muL deionized water drop for sampling the gas and as addition of 4 muL of each of the reactants to form the blue dye (indophenol). Some important analytical parameters were also studied, including sampling time and flow rate. The analytical curve was constructed with a concentration range of 3-20 ppbv of gaseous NH3 standard. The detection limit reached was of ca 0.5 ppbv. It was observed that formaldehyde and diethylamine did not interfere. However, studies showed that hydrogen sulfide caused a negative interference of 20%, when present in the atmosphere in a concentration equal to that of NE3. The method considered here was shown to be easy to apply, making it possible to make a determination every 17 min.

Apoptosis in the epithelial cells of the rests of Malassez of the periodontium of rat molars

Background and Objectives: Epithelial rests of Malassez are clusters of cells derived from Hertwig's root sheath that remain in the periodontal ligament throughout life. Although it is known that the cells of Malassez proliferate, there are no studies showing that they undergo programmed cell death, i.e. apoptosis. In most tissues, proliferation is balanced by apoptosis. Thus we examined regions of the periodontium of young and adult rat molars in the hope of detecting apoptosis.Methods: Wistar rats aged 29, 45 and 120 days were killed with chloral hydrate (600 mg/kg). Fragments containing maxillary molars were removed and fixed in formaldehyde, decalcified, and embedded in paraffin and glycol methacrylate. Sections were stained with hematoxylin/eosin and the Terminal deoxynucleotidyl transferase-mediated dUTP Nick End Labeling (TUNEL) method for detection of apoptosis. Specimens were also fixed in glutaraldehyde-formaldehyde, decalcified and processed for transmission electron microscopy.Results: Epithelial rests of Malassez containing round/ovoid basophilic dense bodies and TUNEL-positive structures were found in all specimens examined. Ultrastructural examination revealed that some cells of Malassez contained masses of condensed peripheral chromatin and a shrunken cytoplasm exhibiting intact organelles - images typical of apoptosis. Moreover, round/ovoid electron-opaque structures appeared to be in the process of being engulfed by neighboring epithelial cells of Malassez.Conclusions: Our results demonstrate that epithelial cells of Malassez's rests undergo apoptosis in the developing and adult periodontium. Apoptosis may, together with proliferation, be part of the mechanism of turnover/remodelling of the cells of Malassez.

Influence of the iron source on the solar photo-Fenton degradation of different classes of organic compounds

In this work the influence of two different iron sources, Fe(NO3)(3) and complexed ferrioxalate (FeOx), on the degradation efficiency of 4-chlorophenol (4CP), malachite green, formaldehyde, dichloroacetic acid (DCA) and the commercial products of the herbicides diuron and tebuthiuron was studied. The oxidation of 4CP, DCA, diuron and tebuthiuron shows a strong dependence on the iron source. While the 4CP degradation is favored by the use of Fe(NO3)(3), the degradation of DCA and the herbicides diuron and tebuthiuron is most efficient when ferrioxalate is used. on the other hand, the degradation of malachite green and formaldehyde is not very influenced by the iron source showing only a slight improvement when ferrioxalate is used. In the case of formaldehyde, DCA, diuron and tebuthiuron, despite of the additional carbon introduced by the use of ferrioxalate, higher mineralization percentages were observed, confirming the beneficial effect of ferrioxalate on the degradation of these compounds. The degradation of tebuthiuron was studied in detail using a shallow pond type solar flow reactor of 4.5 L capacity and 4.5 cm solution depth. Solar irradiation of tebuthiuron at a flow rate of 9 L h(-1), in the presence of 10.0 mmol L-1 H2O2 and 1.0 mmol L-1 ferrioxalate resulted in complete conversion of this herbicide and 70% total organic carbon removal. (c) 2005 Elsevier Ltd. All rights reserved.