Querying semantic catalogues of biomedical databases.

BACKGROUND: Secondary use of health data is a valuable source of knowledge that boosts observational studies, leading to important discoveries in the medical and biomedical sciences. The fundamental guiding principle for performing a successful observational study is the research question and the approach in advance of executing a study. However, in multi-centre studies, finding suitable datasets to support the study is challenging, time-consuming, and sometimes impossible without a deep understanding of each dataset. METHODS: We propose a strategy for retrieving biomedical datasets of interest that were semantically annotated, using an interface built by applying a methodology for transforming natural language questions into formal language queries. The advantages of creating biomedical semantic data are enhanced by using natural language interfaces to issue complex queries without manipulating a logical query language. RESULTS: Our methodology was validated using Alzheimer's disease datasets published in a European platform for sharing and reusing biomedical data. We converted data to semantic information format using biomedical ontologies in everyday use in the biomedical community and published it as a FAIR endpoint. We have considered natural language questions of three types: single-concept questions, questions with exclusion criteria, and multi-concept questions. Finally, we analysed the performance of the question-answering module we used and its limitations. The source code is publicly available at https://bioinformatics-ua.github.io/BioKBQA/. CONCLUSION: We propose a strategy for using information extracted from biomedical data and transformed into a semantic format using open biomedical ontologies. Our method uses natural language to formulate questions to be answered by this semantic data without the direct use of formal query languages.

Disposable electropolymerized molecularly imprinted electrochemical sensor for determination of breast cancer biomarker CA 15-3 in human serum samples.

Initially, a printed electrode was fabricated in a paper substrate using carbon nanotube ink, graphite pencil and silver nanoparticle ink. For that the electrode was modified with gold nanoparticles and a molecularly imprintedpolymer (MIP) using CA 15-3 as target molecule. The Atomic Force Microscopy (AFM) images exhibited the change in the morphology after each electrode modification. The roughness increasedafter the electropolymerization, and decreased after the extraction procedure. Next, slightly increased again associated to the interaction of CA 15-3 and the imprinted sites. Finally, the Fourier Transform Infrared Spectroscopy (FTIR) results suggested the extraction/rebinding of CA 15-3 in the MIP sensor and also indicated that the NIP sample do not have specific cavities for the CA 15-3. In short, under optimized conditions, the CNE/AuNP is incubated with CA 15-3 (40 U mL-1) for 2 h at 4 °C. Then the electropolymerization was carried out in the potential range of -0.2 to 1.0 V during 20 cycles at scan rate of 50 mV s-1 using a solution containing 15 mM of oPD. After electropolymerization, the sensor was washed with oxalic acid solution for 2 h, leading to the formation of imprinted cavities. The rebinding process was subsequently constructed for 1 h at 4 °C using CA 15-3 solution. The reproducibility and interference studies showed that the sensor can be reproducible and specific for CA 15-3. Then the sensor was applied in determination of CA 15-3 in samples of serum and saliva. The use in serum presented good recovery, but the application in saliva was not satisfactory. Therefore, the sensor CNE/AuNP/MIP could be used in the determination of CA 15-3 in serum samples.

An electrochemical sensor modified with a molecularly imprinted polymer and carbon black for 17-ß-estradiol detection.

The purpose of this work was to apply an electrochemical sensor modified with a molecularly imprinted polymer (MIP) and carbon black (CB) for 17ß-estradiol (E2) detection in river water samples. The synthesized MIP was characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM).The modification of the electrode with the MIP and CB contributed to increased sensitivity, an increase of over 173% in relation to that of the bare electrode. The experimental parameters, amount of modifiers, pH and possible interfering species were evaluated. The method showed linearity from 0.10 to 23.0 µmol L-1 and detection and quantification limits of 0.03 and 0.10 µmol L-1, respectively. The application of the developed sensor was considered simple, resulting in a fast, low operating cost method, with recovery values between 103 and 105%.

Fully handwritten electrodes on paper substrate using rollerball pen with silver nanoparticle ink, marker pen with carbon nanotube ink and graphite pencil.

Herein, a so-called carbon nanotube (CNT) electrode was printed in on a paper substrate using the handwriting technique and carbon nanotube ink in a marker pen to print the working electrode, graphite pencil to print the counter electrode and graphite/silver nanoparticle (AgNP) ink in a rollerball pen to print the quasi-reference electrode. The carbon nanotube electrode was characterized via scanning electron microscopy. The electrode was optimized based on the type of paper, hydrophobic barrier and number of layers. In summary, the optimized parameters included the use of matte paper with a mineral spirit layer. The number of carbon nanotube layers to achieve the best electrochemical performance was 25. The final graphite electrode was a miniaturized and flexible paper-based electrochemical electrode. To evaluate the electrical properties of the electrodes, the ohmic resistance of each ink was tested using a multimeter and the obtained values were 18.62 kΩ for the CNT ink, 1.53 Ω for the AgNP ink and 3.53 kΩ for the graphite trace. These results indicate the good conductivity of each synthesized ink used in the fabrication of the CNT electrode. Finally, the electrode was used to measure the electrochemical response of different concentrations of K4[Fe(CN)6]. Then, a calibration curve was obtained from the voltammograms and linearity was observed in the range of 0.5-3.5 mM. This suggests that the CNT electrode has the potential to be used as an amperometric electrode.

Semantic Data Visualisation for Biomedical Database Catalogues.

Biomedical databases often have restricted access policies and governance rules. Thus, an adequate description of their content is essential for researchers who wish to use them for medical research. A strategy for publishing information without disclosing patient-level data is through database fingerprinting and aggregate characterisations. However, this information is still presented in a format that makes it challenging to search, analyse, and decide on the best databases for a domain of study. Several strategies allow one to visualise and compare the characteristics of multiple biomedical databases. Our study focused on a European platform for sharing and disseminating biomedical data. We use semantic data visualisation techniques to assist in comparing descriptive metadata from several databases. The great advantage lies in streamlining the database selection process, ensuring that sensitive details are not shared. To address this goal, we have considered two levels of data visualisation, one characterising a single database and the other involving multiple databases in network-level visualisations. This study revealed the impact of the proposed visualisations and some open challenges in representing semantically annotated biomedical datasets. Identifying future directions in this scope was one of the outcomes of this work.

Discovery of Biomedical Databases Through Semantic Questioning.

Many clinical studies are greatly dependent on an efficient identification of relevant datasets. This selection can be performed in existing health data catalogues, by searching for available metadata. The search process can be optimised through questioning-answering interfaces, to help researchers explore the available data present. However, when searching the distinct catalogues the lack of metadata harmonisation imposes a few bottlenecks. This paper presents a methodology to allow semantic search over several biomedical database catalogues, by extracting the information using a shared domain knowledge. The resulting pipeline allows the converted data to be published as FAIR endpoints, and it provides an end-user interface that accepts natural language questions.

Determination of organophosphorus compounds in water and food samples using a non-enzymatic electrochemical sensor based on silver nanoparticles and carbon nanotubes nanocomposite coupled with batch injection analysis.

This work presents, for the first time, a fast and highly sensitive electrochemical method for determination of three organophosphorus compounds (OPs), diazinon (DZN), malathion (MLT), and chlorpyrifos (CLPF), using a modified pyrolytic graphite electrode (PGE) coupled to batch injection analysis system with multiple pulse amperometric detection (BIA-MPA). The PGE was modified by a nanocomposite based on functionalized carbon nanotubes (CNTf) and silver nanoparticles (AgNPs). The OPs samples were directly analyzed on the modified working electrode surface by BIA-MPA system in Britton-Robinson (BR) buffer 0.15 mol L-1 at pH 6.0. The MPA detection of DZN, MLT and CLPF was performed using two potential pulses, which were sequentially applied on modified PGE at -1.3 V (100 ms) and +0.8 V (100 ms) for selective determination of these three OPs and working electrode cleaning, respectively. Under optimized conditions, the sensor presented a linear range of 0.1-20 µmol L-1 for DZN, 1.0-30 µmol L-1 for MLT and from 0.25 to 50 µmol L-1 for CLPF. The limits of detection (LOD) and quantification (LOQ) of 0.35 and 1.18 µmol L-1 for DZN, 0.89 and 2.98 µmol L-1 for MLT, and 0.53 and 1.78 µmol L-1 for CLPF were obtained. The proposed method exhibited high sensitivity of 0.068, 0.030 and 0.043 mA L µmol-1 for DZN, MLT and CLPF detection, respectively. Furthermore, the BIA-MPA system provided an analytical frequency of 71 determinations per hour for direct determination of these OPs in water and food samples. The modified PGE coupled to BIA-MPA system showed a high stability of electrochemical response for OPs detection with relative standard deviation (RSD) of 1.60% (n = 20). The addition-recovery studies of the proposed method were carried out in tap water, orange juice, and apple fruit real samples, which showed suitable recovery values between 77 and 124%. The analytical performance of the developed sensor provides an attractive alternative method for OPs determination with great potential for a fast and sensitive application in contaminated samples with these pesticides.

Electrochemical biosensors for neglected tropical diseases: A review.

A group of infectious and parasitic diseases with prevalence in tropical and subtropical regions of the planet, especially in places with difficult access, internal conflicts, poverty, and low visibility from the government and health agencies are classified as neglected tropical diseases. While some well-intentioned isolated groups are making the difference on a global scale, the number of new cases and deaths is still alarming. The development and employment of low-cost, miniaturized, and easy-to-use devices as biosensors could be the key to fast diagnosis in such areas leading to a better treatment to further eradication of such diseases. Therefore, this review contains useful information regarding the development of such devices in the past ten years (2010-2020). Guided by the updated list from the World Health Organization, the work evaluated the new trends in the biosensor field applied to the early detection of neglected tropical diseases, the efficiencies of the devices compared to the traditional techniques, and the applicability on-site for local distribution. So, we focus on Malaria, Chagas, Leishmaniasis, Dengue, Zika, Chikungunya, Schistosomiasis, Leprosy, Human African trypanosomiasis (sleeping sickness), Lymphatic filariasis, and Rabies. Few papers were found concerning such diseases and there is no available commercial device in the market. The works contain information regarding the development of point-of-care devices, but there are only at proof of concepts stage so far. Details of electrode modification and construction of electrochemical biosensors were summarized in Tables. The demand for the eradication of neglected tropical diseases is increasing. The use of biosensors is pivotal for the cause, but appliable devices are scarce. The information present in this review can be useful for further development of biosensors in the hope of helping the world combat these deadly diseases.

SCALEUS-FD: A FAIR Data Tool for Biomedical Applications.

The Semantic Web and Linked Data concepts and technologies have empowered the scientific community with solutions to take full advantage of the increasingly available distributed and heterogeneous data in distinct silos. Additionally, FAIR Data principles established guidelines for data to be Findable, Accessible, Interoperable, and Reusable, and they are gaining traction in data stewardship. However, to explore their full potential, we must be able to transform legacy solutions smoothly into the FAIR Data ecosystem. In this paper, we introduce SCALEUS-FD, a FAIR Data extension of a legacy semantic web tool successfully used for data integration and semantic annotation and enrichment. The core functionalities of the solution follow the Semantic Web and Linked Data principles, offering a FAIR REST API for machine-to-machine operations. We applied a set of metrics to evaluate its "FAIRness" and created an application scenario in the rare diseases domain.

Assessment of the Performance of Solid Phase Extraction Based on Pipette Tip Employing a Hybrid Molecularly Imprinted Polymer as an Adsorbent for Enantioselective Determination of Albendazole Sulfoxide.

Herein, an organic-inorganic hybrid molecularly imprinted polymer (MIP) was successfully synthesized with albendazole sulfoxide (ABZSO) as a template and 3-(trimethoxysilyl)propyl methacrylate, a bifunctional group compound, as a single cross-linking agent. In this study, a simple method using HPLC-DAD was developed for the determination of ABZSO enantiomers in human urine using pipette tip-based molecularly imprinted polymer solid phase extraction (PT-MIP-SPE). Enantioseparation with satisfactory retention times (5.17 and 7.09 min), acceptable theoretical plates (N = 4,535 and 5,091) and strong resolution (Rs = 5.45) was performed with an Agilent® Eclipse Plus C18 (100 mm × 4.6 mm, 3.5 µm) coupled with a Chiralpak® IA column (100 mm × 4.6 mm, 3 µm), a mixture with ethanol:water (50:50, v/v) as the mobile phase, temperature at 40°C, flow rate at 0.9 mL min-1 and λ = 230 nm. Thereafter, certain parameters affecting the PT-MIP-SPE were investigated in detail and the better conditions were: 300 µL of water as washing solvent, 500 µL of ethanol:acetic acid (9:1, v/v) as eluting solvent, 20 mg of MIP, 500 µL of human urine at pH 9 and no addition of NaCl. Recoveries/relative standard deviation (RSD%) for (R)-(+)-ABZSO and (S)-(-)-ABZSO were 78.2 ± 0.2% and 69.7 ± 1.7%, respectively.

Molecularly imprinted pipette-tip solid phase extraction for selective determination of fluoroquinolones in human urine using HPLC-DAD.

A simple method using HPLC-DAD was developed for the determination of fluoroquinolones in human urine including ciprofloxacin (CIPRO), enrofloxacino (ENRO), marbofloxacino (MARBO) and norfloxacin (NOR). In addition, it was studied the extraction of fluoroquinolones in human urine samples using pipette tip-based molecularly imprinted polymers solid phase extraction (PT-MIPs-SPE). With the goal of finding the best procedure for extraction of four fluoroquinolones in human urine, several parameters that are likely to affect the efficiency of extraction during sample preparation, including the washing solvent, type and volume of eluent, amount of material, the volume of the sample, pH and the ionic strength were systematically optimized. Chromatographic separations of fluoroquinolones were hit within 10min using a Synergi(®) C18 (250×4.6mm, 4µm) column and mobile phase consisting of water (10mM of phosphoric acid, the pH adjusted at 3.29 with triethylamine) : acetonitrile (85.7: 14.3, v/v) at a flow rate of 1.5mLmin(-1). Detection was performed at 290nm. The average extraction recoveries/standard deviation relative to ENRO, CIPRO, NOR and MARBO were 96.40±5.51%, 42.47±4.81%, 41.82±7.99% and 87.49±4.70, respectively. The method was liner from 39 to 1260ngmL(-1) for each fluoroquinolone with correlation coefficient of 0.9904, 0.9910, 0.9914 and 0.9919, to ENRO, CIPRO, NOR and MARBO, respectively. The assays of within-day and between-day precision and accuracy for all analytes were studied at three concentration levels and were lower than 15%. The method was successfully employed in a preliminary cumulative urinary excretion study after administration of CIPRO to a healthy volunteer.

Electrochemical behavior of riboflavin immobilized on different matrices.

The electrochemical behavior of riboflavin (RF) adsorbed on different surfaces of inorganic matrices was investigated using modified carbon paste electrodes. Silica gel and sol-gel silica modified with niobium oxide were denominated as (SN) and (SN(sol-gel)), respectively. These materials were treated with a H3PO4 solution to graft phosphate groups and were denominated as (SNP) and (SNP(sol-gel)). The immobilization of RF on these materials indicated a high electrode stability, avoiding leaching out of the electroactive species (RF) from the electrode surface. The values of formal potential (E0') of the adsorbed RF on the different matrices changed from -283 (SNRF) up to -165 mV (SNPRF(sol-gel)) vs SCE in 0.1 moll(-1) NaNO3 solution at pH 7.0. Compared to the E0' for soluble RF, the values are shifted 183 up to 305 mV toward more positive potentials. The stability of the electrodes and the formal potential of the adsorbed RF on different matrices remained constant upon changing the solution pH from 3 to 8. Some kinetic parameters were estimated; indicating that all systems studied presented a good electron transfer rate.

Electrochemical behavior and electrocatalytic study of the methylene green coated on modified silica gel.

The electrochemical behavior of methylene green (MG) adsorbed on a silica surface modified with niobium oxide (SN) was investigated, using modified carbon paste electrodes. It was also used in an electrocatalytic study of NADH oxidation. The electrode showed a high stability attributed to the presence of SN, which avoids the leaching of the mediator from the electrode surface. The formal potential (E(0')) of the adsorbed MG was -35 mV vs SCE, showing a shift of 30 mV toward more positive potential values, compared to the MG dissolved in aqueous solution. This shift was assigned to the interaction between the basic nitrogen of MG and the acid sites of SN. The variation of the solution pH between 4 and 8 did not affect the stability nor the formal potential. However, for solution pH lower than 4 the formal potential was affected by the acidity of the medium. The electrocatalytic oxidation of NADH at the electrode was investigated. In the solution pH between 5 and 8 the electrocatalytic activity remained almost constant, giving a response signal of 13.3 nA L micromol(-1) cm(-2) and a K(Mapp) of 1.4 x 10(-5) mol L(-1). The electrode gave a linear response range between 5.0 x 10(-4) and 4.0 x 10(-3) mol L(-1) NADH concentration at pH 7.0 at an applied potential of 50 mV vs SCE. Applying a flow injection analysis system, the electrode showed a better analytical performance for NADH detection, presenting a linear response range between 6.0 x 10(-5) and 1.0 x 10(-3) mol L(-1), with an analytical frequency of 30 determinations/h, a detection limit of 8.2 x 10(-6) mol L(-1), and a precision for 25 replicates of 1% expressed as a relative standard deviation.

A highly improved method for sensitive determination of amitriptyline in pharmaceutical formulations using an unmodified carbon nanotube electrode in the presence of sulfuric acid.

The present paper describes a novel, simple and reliable differential pulse voltammetric method for determining amitriptyline (AMT) in pharmaceutical formulations. It has been described for many authors that this antidepressant is electrochemically inactive at carbon electrodes. However, the procedure proposed herein consisted in electrochemically oxidizing AMT at an unmodified carbon nanotube paste electrode in the presence of 0.1 mol L(-1) sulfuric acid used as electrolyte. At such concentration, the acid facilitated the AMT electroxidation through one-electron transfer at 1.33 V vs. Ag/AgCl, as observed by the augmentation of peak current. Concerning optimized conditions (modulation time 5 ms, scan rate 90 mV s(-1), and pulse amplitude 120 mV) a linear calibration curve was constructed in the range of 0.0-30.0 µmol L(-1), with a correlation coefficient of 0.9991 and a limit of detection of 1.61 µmol L(-1). The procedure was successfully validated for intra- and inter-day precision and accuracy. Moreover, its feasibility was assessed through analysis of commercial pharmaceutical formulations and it has been compared to the UV-vis spectrophotometric method used as standard analytical technique recommended by the Brazilian Pharmacopoeia.

Exame colpocitológico: perfil epidemiológico em uma Estratégia Saúde da Família / Papanicolaou test: epidemiological profile in a Family Health Strategy

Objetivo: verificar a freqüência de alterações sugestivas de Câncer do Colo do Útero, de agosto de 2013 até agosto 2014, através da avaliação dos resultados dos exames de Papanicolau, registrados nos livros de acompanhamento de mulheres no controle do Câncer do Colo do Útero, realizados em mulheres a partir da adolescência até a senescência. Casuística e Métodos: estudo transversal realizado a partir de dados coletados na Estratégia Saúde da Família Vila Mutirão, pertencente à Região Noroeste da Cidade de Goiânia ­ Goiás ­Brasil. Resultados: Dentre os dados analisados das 747 pacientes, 644 (86,21%) não apresentaram indícios ou constatações de Câncer do Colo do Útero, 70 (9,38%) não apresentaram dados. Ainda, 33 (4,4) apresentaram algum tipo de lesão sugestiva pré-cancerígena, pré-cancerígena propriamente dita ou cancerígena, sendo que destas, 18 (2,40%) evidenciaram lesão sugestiva pré-cancerígena, 15 (2,00%) lesão pré-cancerígena, nenhuma (0%) apresentou lesões cancerígenas. Conclusão: neste estudo avaliou-se a frequência de alterações, sendo mínima a prevalência de lesões precursoras ou sugestivas de câncer do colo do útero. Verificaram-se também associações semelhantes sobre os fatores de risco relacionados ao câncer do colo do útero (idade e escolaridade)

Objective: To verify the frequency of changes suggestive of cervical cancer, from August 2013 to August 2014, by evaluating the results of the Pap smears, recorded in the books accompanying women in the control of cervical cancer, performed in women - from adolescence to senescence. Methods: a cross - sectional study based on data collected in the Vila Mutirão Family Health Strategy, belonging to the Northwest Region of the City of Goiânia - Goiás - Brazil. Results: Among the 747 patients analyzed, 644 (86.21%) had no evidence or findings of cervical cancer, 70 (9.38%) did not present data. Still, 33 (4,4) presented some pre-cancerous, pre-cancerous or carcinogenic suggestive lesion, of which 18 (2.40%) showed suggestive precancerous lesion, 15 (2.00%) precancerous lesion, none (0%) presented carcinogenic lesions. Conclusion: this study evaluated the frequency of alterations, with minimal prevalence of cervical or cervical cancer precursor lesions. Similar associations were also found on risk factors related to cervical cancer (age and schooling)

Simultaneous determination of zinc, cadmium and lead in environmental water samples by potentiometric stripping analysis (PSA) using multiwalled carbon nanotube electrode.

The present paper has focused on the potential application of multiwalled carbon nanotube for the development of a new, simple and highly selective electrochemical method for simultaneous Zn (II), Cd (II) and Pb (II) monitoring in water samples (lake and effluent waters), by using potentiometric stripping analysis (PSA). The electrochemical method is based on simultaneous preconcentration/reduction of metal ions onto a multiwall carbon nanotube electrode at -1.3V (versus Ag/AgCl(sat)) in 0.3 mol L(-1) acetate solution containing 15 mg L(-1) Hg (II) ions during 180s, followed by subsequent chemical stripping. The analytical curve for all analytes covered the linear range varying from 58.4 up to 646.2 microg L(-1) with correlation coefficients higher than 0.981. The limits of detection for Zn (II), Cd (II) and Pb (II) were found to be 28.0, 8.4 and 6.6 microg L(-1), while the relative standard deviation (RSD) at 352 microg L(-1) was 5.6, 7.1 and 5.6% (n=5), respectively. The behavior of the simultaneous determination in the presence of following ions Co (II), Cr (III) and Cu (II) was affected by using the analyte:interferent ratio 1:10. Therefore, by using standard addition method, Zn (II), Cd (II) and Pb (II) ions in lake and effluent water samples were determined after the spiking procedure and the results were successfully compared with those obtained by atomic absorption spectrometry (AAS). The obtained results suggest that the proposed method can be applied as a simple and efficient alternative for the simultaneous monitoring of heavy metals in water samples, according to those established requirements from environmental organizations. In addition, this method demonstrates the powerful application of carbon nanotubes in the field of potentiometric stripping analysis.

Solid-phase extraction system for Pb (II) ions enrichment based on multiwall carbon nanotubes coupled on-line to flame atomic absorption spectrometry.

The present paper proposes the application of multiwall carbon nanotubes (MWCNTs) as a solid sorbent for lead preconcentration using a flow system coupled to flame atomic absorption spectrometry. The method comprises the preconcentration of Pb (II) ions at a buffered solution (pH 4.7) onto 30mg of MWCNTs previously oxidized with concentrated HNO(3). The elution step is carried out with 1.0molL(-1) HNO(3). The effect of the experimental parameters, including sample pH, sampling flow rate, buffer and eluent concentrations were investigated by means of a 2(4) full factorial design, while for the final optimization a Doehlert design was employed. Under the best experimental conditions the preconcentration system provided detection and quantification limits of 2.6 and 8.6mugL(-1), respectively. A wide linear range varying from 8.6 up to 775mugL(-1) (r>0.999) and the respective precision (relative standard deviation) of 7.7 and 1.4% for the 15 and 200mugL(-1) levels were obtained. The characteristics obtained for the performance of the flow preconcentration system were a preconcentration factor of 44.2, preconcentration efficiency of 11min(-1), consumptive index of 0.45mL and sampling frequency estimated as 14h(-1). Preconcentration studies of Pb (II) ions in the presence of the majority foreign ions tested did not show interference, attesting the good performance of MWCNTs. The accuracy of the method was assessed from analysis of water samples (tap, mineral, physiological serum and synthetic seawater) and common medicinal herbs submitted to the acid decomposition (garlic and Ginkgo Biloba). The satisfactory recovery values obtained without using analyte addition method confirms the feasibility of this method for Pb (II) ions determination in different type of samples.

Avaliaçäo de técnicas de moldagem com alginato para próteses totais / Evaluation of impression techniques with alginate for complete dentures

Este estudo visa comparar a fidelidade dimensional dos modelos obtidos com alginato quando as técnicas convencional e de dupla moldagem com alginato säo utilizadas para a confecçäo de prótese total. Confeccionou-se um modelo mestre em acrílico autopolimerizável, simulando uma arcada superior totalmente desdentada. Quatorze moldes utilizando alginato foram obtidos com a aplicaçäo das duas técnicas: sete pela dupla moldagem e sete pela convencional. Os moldes foram vazados imediatamente com gesso tipo IV, näo se recorrendo a nenhum tipo de armazenamento. Os corpos-de-prova foram mensurados através de um paquímetro digital, e os resultados, submetidos à análise de variância e ao método de Tukey, näo sendo constatada diferença significativa entre as técnicas empregadas. Concluiu-se que a aplicaçäo da técnica de dupla moldagem com alginato está, assim, bem indicada, devido à boa aceitaçäo pelos pacientes, ao menor custo e à menor exigência de tempo clínico

Lipoma del cuerpo calloso / Lipoma of the corpus collosum

Referimos un nuevo caso de lipoma del cuerpo calloso cuyo diagnóstico se realiza por los estudios neurorradiológicos. Se señala la utilidad de la radiografía simple del cráneo que orienta el diagnóstico. Se describen las alteraciones angiográficas que son típicas de la afección y se enumeran las alteraciones de la TAC por lo que se evidencia que este estudio es el más útil y práctico y permite garantizar la identificación del proceso con un método de diagnóstico no invasivo. El lipoma del cuerpo calloso es una afección de presentación poco frecuente, cuyo diagnóstico se efectúa atendiendo a los hallazgos neurorradiológicos. Hay algo más de 100 ejemplos referidos en la literatura . Nosotros comunicamos el caso de un nuevo paciente y discutimos las características de la entidad