RESUMO
This study performed an analysis of the influence of the training and test set rational selection on the quality and predictively of the quantitative structure-activity relationship (QSAR) model. The study was carried out on three different datasets of Influenza Neuraminidase (H1N1) inhibitors. The three datasets were divided into training and test sets using three rational selection methods: based on k-means, Kennard-Stone algorithm and Activity and the results were compared with Random selection. Then, a total of 31,490 mathematical models were developed and those models that presented a determination coefficient higher than: r2train > 0.8, r2loo > 0.7, r2test > 0.5 and minimum standard deviation (SD) and minimum root-mean square error (RMS) were selected. The selected models were validated using the internal leave-one-out method and the predictive capacity was evaluated by the external test set. The results indicate that random selection could lead to erroneous results. In return, a rational selection allows for obtaining more reliable conclusions. The QSAR models with major predictive power were found using the k-means algorithm and selection by activity.
Assuntos
Antivirais/química , Neuraminidase/antagonistas & inibidores , Relação Quantitativa Estrutura-Atividade , Algoritmos , Antivirais/análise , Vírus da Influenza A Subtipo H1N1 , Modelos MolecularesRESUMO
In some patients with labial white stains involving the enamel and dentin, bleaching associated with a restorative procedure using composites may be an appropriate treatment alternative. Although bleaching makes the teeth and the stain whiter, the staining is less evident and easier to restore. Restorative procedures using adequate composites may then recover the natural optical properties while also providing appropriate mechanical properties, thereby ensuring the longevity of the treatment. In this article, the clinical case of a 9-year-old patient who reported dissatisfaction with her smile because of the presence of hypoplastic enamel staining at the central superior and inferior incisors is reported. The treatment consisted of a bleaching protocol followed by composite resin restorations using the stratification technique. The final esthetic result demonstrated the possibility of obtaining a natural smile with an adequate color and natural-looking restorations, thereby ensuring the esthetics and the patient's functional satisfaction.
Assuntos
Hipoplasia do Esmalte Dentário/terapia , Incisivo/patologia , Peróxido de Carbamida , Criança , Cor , Resinas Compostas/química , Esmalte Dentário/patologia , Hipoplasia do Esmalte Dentário/diagnóstico , Materiais Dentários/química , Restauração Dentária Permanente/métodos , Dentina/patologia , Estética Dentária , Feminino , Humanos , Peróxidos/uso terapêutico , Sorriso , Clareamento Dental/métodos , Clareadores Dentários/uso terapêutico , Preparo do Dente/métodos , Transiluminação/métodos , Ureia/análogos & derivados , Ureia/uso terapêuticoRESUMO
Postweaning multisystemic wasting syndrome was first described in Canada in 1991 and at present an increasing number of cases has been diagnosed worldwide. In Argentina the first cases of PMWS were reported recently. Forty eight 5 to 12 week old pigs with signs characteristic of PMWS from 19 farms were studied. Although the real distribution of the virus in our country is not known it was observed an increasing number of farms with PMWS distributed in the major producing provinces. The histopathology was an important tool in diagnosis of suspicious cases of PMWS with the observation of different degrees of lesion. In the studied animals, the secondary infections, either by opportunistic pathogens or secondary bacteria could be important.
Assuntos
Infecções por Circoviridae/veterinária , Doenças dos Suínos/patologia , Síndrome de Emaciação/patologia , Animais , Argentina/epidemiologia , Infecções Bacterianas/epidemiologia , Infecções Bacterianas/microbiologia , Infecções Bacterianas/patologia , Infecções Bacterianas/veterinária , Sistema Nervoso Central/patologia , Sistema Nervoso Central/virologia , Infecções por Circoviridae/epidemiologia , Infecções por Circoviridae/patologia , Infecções por Circoviridae/virologia , Circovirus/isolamento & purificação , Células Gigantes/virologia , Corpos de Inclusão Viral/ultraestrutura , Linfonodos/patologia , Linfonodos/virologia , Macrófagos/virologia , Infecções Oportunistas/epidemiologia , Infecções Oportunistas/microbiologia , Infecções Oportunistas/patologia , Infecções Oportunistas/veterinária , Superinfecção , Sus scrofa , Doenças dos Suínos/epidemiologia , Doenças dos Suínos/virologia , Vísceras/patologia , Vísceras/virologia , Síndrome de Emaciação/epidemiologia , Síndrome de Emaciação/virologiaRESUMO
El síndrome del desmedro multisistémico postdestete (PMWS) fue descrito por primera vez en Canadá en el año 1991 y desde entonces un número creciente de casos han sido diagnosticados en todo el mundo. En la Argentina, el PMWS fue reportado por primera vez recientemente. Se estudiaron 48 cerdos de 5 a 12 semanas de edad con signos característicos de PMWS procedentes de 19 granjas. Si bien se desconoce la distribución real del virus en nuestro país se observó desde el año 2001 un número creciente de granjas con PMWS y distribuidas en las principales provincias productoras. La histopatología fue una herramienta diagnóstica importante en casos sospechosos de PMWS con la observación de diferentes grados de lesión. En los animales estudiados las infecciones secundarias pudieron ser importantes, ya sea por patógenos oportunistas o por complicaciones bacterianas.
Postweaning multisystemic wasting syndrome was first described in Canada in 1991 and at present an increasing number of cases has been diagnosed worldwide. In Argentina the first cases of PMWS were reported recently. Forty eight 5 to 12 week old pigs with signs characteristic of PMWS from 19 farms were studied. Although the real distribution of the virus in our country is not known it was observed an increasing number of farms with PMWS distributed in the major producing provinces. The histopathology was an important tool in diagnosis of suspicious cases of PMWS with the observation of different degrees of lesion. In the studied animals, the secondary infections, either by opportunistic pathogens or secondary bacteria could be important.
Assuntos
Animais , Infecções por Circoviridae/veterinária , Doenças dos Suínos/patologia , Síndrome de Emaciação/patologia , Argentina/epidemiologia , Infecções Bacterianas/epidemiologia , Infecções Bacterianas/microbiologia , Infecções Bacterianas/patologia , Infecções Bacterianas/veterinária , Sistema Nervoso Central/patologia , Sistema Nervoso Central/virologia , Infecções por Circoviridae/epidemiologia , Infecções por Circoviridae/patologia , Infecções por Circoviridae/virologia , Circovirus/isolamento & purificação , Células Gigantes/virologia , Corpos de Inclusão Viral/ultraestrutura , Linfonodos/patologia , Linfonodos/virologia , Macrófagos/virologia , Infecções Oportunistas/epidemiologia , Infecções Oportunistas/microbiologia , Infecções Oportunistas/patologia , Infecções Oportunistas/veterinária , Superinfecção , Sus scrofa , Doenças dos Suínos/epidemiologia , Doenças dos Suínos/virologia , Vísceras/patologia , Vísceras/virologia , Síndrome de Emaciação/epidemiologia , Síndrome de Emaciação/virologiaRESUMO
Postweaning multisystemic wasting syndrome was first described in Canada in 1991 and at present an increasing number of cases has been diagnosed worldwide. In Argentina the first cases of PMWS were reported recently. Forty eight 5 to 12 week old pigs with signs characteristic of PMWS from 19 farms were studied. Although the real distribution of the virus in our country is not known it was observed an increasing number of farms with PMWS distributed in the major producing provinces. The histopathology was an important tool in diagnosis of suspicious cases of PMWS with the observation of different degrees of lesion. In the studied animals, the secondary infections, either by opportunistic pathogens or secondary bacteria could be important.
RESUMO
Porcine enzootic pneumonia (PEN), caused by Mycoplasma hyopneumoniae (Mh), has been described in pigs in all geographic areas. The disease is characterized by high morbidity and low mortality rates in intensive swine production systems. A morphologic and immunohistochemical study was done to determine the cellular populations present in lung parenchyma of infected pigs, with special attention to the bronchus-associated lymphoid tissue (BALT). Polyclonal and monoclonal antibodies were used for the detection of antigens of Mh, T lymphocytes (CD3+, CD4+, and CD8+), IgG+ or IgA+ lymphocytes, and cells containing lysozyme, S-100 protein, major histocompatibility complex class II antigen or myeloid-histiocyte antigen. Findings in lung tissues associated with Mh infection were catarrhal bronchointerstitial pneumonia, with infiltration of inflammatory cells in the lamina propria of bronchi and bronchioles and alveolar septa. Hyperplasia of mononuclear cells in the BALT areas was the most significant histologic change. The BALT showed a high morphologic and cellular organization. Macrophages and B lymphocytes were the main cellular components of germinal centers. T lymphocytes were primarily located in perifollicular areas of the BALT, lamina propria and within the airway epithelium, and plasma cells containing IgG or IgA at the periphery of the BALT, in the lamina propria of bronchi and bronchioles, in alveolar septa, and around bronchial submucosal glands. The hyperplastic BALT in PEN cases consisted of macrophages, dendritic cells, T and B lymphocytes, and IgG+ and IgA+ plasma cells. CD4+ cells predominated over CD8+ cells. Local humoral immunity appears to play an important role in the infection.
Assuntos
Brônquios/microbiologia , Brônquios/patologia , Tecido Linfoide/microbiologia , Tecido Linfoide/patologia , Infecções por Mycoplasma/patologia , Infecções por Mycoplasma/veterinária , Mycoplasma/fisiologia , Animais , Brônquios/ultraestrutura , Imuno-Histoquímica , Tecido Linfoide/ultraestrutura , Infecções por Mycoplasma/microbiologia , Suínos , Doenças dos Suínos/microbiologia , Doenças dos Suínos/patologiaAssuntos
Infecções por Circoviridae/veterinária , Circovirus/patogenicidade , Doenças dos Suínos/epidemiologia , Síndrome de Emaciação/veterinária , Animais , Argentina , Infecções por Circoviridae/epidemiologia , Infecções por Circoviridae/fisiopatologia , Suínos , Doenças dos Suínos/fisiopatologia , Síndrome de Emaciação/epidemiologia , Síndrome de Emaciação/fisiopatologiaRESUMO
UNLABELLED: The functional and esthetic restoration of severely compromised anterior teeth is a challenge to clinicians in their daily practice. The duplication of the optical characteristics of an intact tooth, including shade, translucency, and fluorescence, is often made difficult by the use of metal infrastructures, such as post-and-cores and copings. The development of reinforced ceramics and non-metallic post systems made possible the generation of metal-free ceramic restorations in severely compromised anterior and posterior teeth. This article discusses one available technique for the generation of a single all-ceramic restoration involving the use of a zirconia- or leucite-reinforced post-and-core system and of an all-ceramic crown system. A representative clinical case is presented illustrating the potential of the technique. CLINICAL SIGNIFICANCE: Modern ceramic restorative systems offer the possibility to closely match the natural optical characteristics of lost tooth structure. Posts, cores, and copings fabricated in ceramic materials represent a promising alternative to metals in the restoration of severely compromised anterior teeth.
Assuntos
Coroas , Porcelana Dentária , Técnica para Retentor Intrarradicular , Adulto , Óxido de Alumínio , Silicatos de Alumínio , Materiais Dentários , Feminino , Humanos , Retratamento , ZircônioRESUMO
STATEMENT OF PROBLEM: Veneer preparations are considered to weaken endodontically treated maxillary incisors. Prefabricated posts have been controversially indicated to reinforce endodontically treated teeth before final restoration. PURPOSE: This in vitro study evaluated whether (1) veneer preparation in enamel or in enamel/dentin weakens endodontically treated maxillary incisors, (2) bonding of direct composite veneer restores the original strength of the unprepared teeth, and (3) use of prefabricated metal posts increases fracture resistance of prepared and restored teeth. MATERIAL AND METHODS: Ninety extracted human maxillary central incisors were submitted to conventional root canal treatment. Specimens were randomly divided into 8 experimental groups (veneer preparation in enamel or dentin with/without post and with/without direct composite veneer restoration) and a control group (n = 10). Specimens were loaded to fracture, and the data were analyzed statistically. RESULTS: Statistical analysis revealed that a conservative veneer preparation does not significantly reduce maxillary incisors' fracture resistance. For prepared incisors, bonding of direct composite veneer restored their original strength, and the use of posts did not increase their fracture resistance. CONCLUSION: Conservative veneer preparations involving enamel and enamel/dentin did not significantly reduce the fracture resistance of endodontically treated maxillary incisors. In addition, restoration of the intraenamel preparations with direct composite resulted in teeth more resistant to fracture than teeth having restorations in dentin. The use of posts did not improve fracture resistance of endodontically treated maxillary incisors reduced and veneered with direct composite.
Assuntos
Facetas Dentárias , Técnica para Retentor Intrarradicular , Fraturas dos Dentes/prevenção & controle , Dente não Vital , Análise de Variância , Resinas Compostas , Análise do Estresse Dentário , Facetas Dentárias/efeitos adversos , Humanos , Incisivo/lesões , Maxila , Estatísticas não Paramétricas , Fraturas dos Dentes/etiologiaRESUMO
The purpose of this in vitro study was to compare marginal leakage of class 2 light-cured composite resin restorations, with different insertion and polymerization techniques. Fifty sound premolars extracted for prosthetic purposes were used in the study. Conservative class 2 (MOD) preparations were made in all teeth, with one proximogingival margin on enamel and the other on cementum. All the preparations and restorations were performed by the same operator utilizing the same restorative materials. After restoration the teeth were thermocycled and their gingival margins exposed to a dye. Results showed that the kind of matrix system had no significant influence upon the degree of marginal leakage on enamel. On cementum, oblique and horizontal incremental insertion and polymerization techniques using the collimator cone exhibited the least leakage, while the clear matrix band/reflective wedge technique presented the greatest leakage.