Effect of a static non-uniform magnetic field on the surface properties of acrylic resin

INTRODUCTION: The acrylic resin is a polymeric material with several applications in different scientific and technological fields, especially in medicine and biotechnology. Its physical characteristics or their possible modifications can imply new ways of utilization and applicability. OBJECTIVE: To study the effect of a magnetic field on the surface physico-chemical properties usually implied in bacterial adhesion, especially surface hydrophobicity. METHODS: the hydrophobicity of the resin surface was determined by sessile drop contact angle measurements, using van Oss (1994) methodology. Accordingly, a substance (i) is considered hydrophobic when the variation of the free energy of interaction between two entities of substance (i) immersed in water is negative (DGiwi<0). That is to say, the two entities of substance (i) interact preferentially between them then with water. On the contrary, if DGiwi>0, substance (i) is hydrophilic. Two types of resin samples were used: hydrated and non-hydrated ones. The hydrated samples were obtained by autoclaving at 121ºC. Before contact angle measurements, the samples submitted to the magnetic field were exposed during 24 hours to a field of 500gauss generated between to parallel magnetite plates. RESULTS AND DISCUSSION: The principal results are summarized in Table 1. As could be expected the hydrated resin is hydrophilic, while the dehydrated is hydrophobic. However, when the hydrated resin is submitted to the magnetic field it becomes even more hydrophobic than when dehydrated. This can be explained by the effect of the magnetic field on the orientation of the water molecules of hydration. Consequently, there is an evident alteration of surface properties promoted by the magnetic field

Candida albicans enhanced phospholipase production after exposition to a static non-uniform magnetic field

INTRODUCTION: Microbial virulence factors are responsible for tissue damage in hosts. Candida albicans is an opportunistic pathogen that constitutes an increasing risk of infection, especially for immunosuppressed or immunocompromised patients. OBJECTIVE: The objective of this study was to determine the effect of a static non-uniform magnetic field on the phenotype expression of different strains of Candida albicans. METHODS: The strains of Candida albicans were grown on phospholipase-agar, according to Shimizu et al. (1996) and incubated at 37 ºC inside a magnetic field (except the assays used as blank). The magnetic field was generated by two magnetite plates (Figure 1) and standardized as a function of distance versus number of magnetic plates (Figure 2). The magnetic field was of 500 gauss in the central part between the two magnetic plates. RESULTS: The preliminary results show a visible increase in the halo formed due to phospholipase production, suggesting that the exposition to a magnetic field can enhance the expression of this virulence factor

Leveduras da cavidade oral de crianças com AIDS: produção de exoenzimas e resistência antifúngica

The oral fungal microbiota of 30 children with AIDS, of both genders, aged from two to six years, receiving outpatient treatment, was evaluated and compared with that of a control group composed of 30 healthy subjects with matching ages and genders. Virulence factors, such as exoenzyme production, and susceptibility to five antifungal agents using an E-Test kit were evaluated. C. albicans predominated over other species in the AIDS group, showing a higher production of proteinase and phospholipase when compared with that observed in the control group. In this study few clinical manifestations of and low selectivity for C. albicans (23.3%) were observed in the AIDS group. The enzymatic studies showed that 53.8% of the AIDS strains were strongly positive whereas only 33.3% of the non-AIDS strains were positive. Amphotericin B was the most effective drug among the antifungal agents tested against C. albicans. The frequency, selectivity and level of exoenzyme production by C. albicans suggest a higher pathogenicity in the AIDS children than in the control children.A microbiota fúngica bucal de 30 crianças com AIDS, de ambos os gêneros, com idades entre dois e seis anos, recebendo atendimento ambulatorial, foi avaliada e comparada com a de um grupo controle constituído de 30 indivíduos saudáveis com idades e gêneros equivalentes. Fatores de virulência, tais como a produção de exoenzimas, e a suscetibilidade dos microorganismos a cinco agentes antifúngicos, medida por meio de um kit E-Test, foram avaliados. O microorganismo C. albicans predominou sobre outras espécies no grupo com AIDS, demonstrando uma maior produção de proteinase e fosfolipase quando comparada com a produção observada no grupo controle. No grupo com AIDS, foram observadas poucas manifestações clínicas de C. albicans, além de uma baixa seletividade para o microorganismo (23,3%). Os estudos enzimáticos mostraram que 53,8% das linhagens no grupo com AIDS foram fortemente positivas, ao passo que apenas 33,3% o foram no grupo controle. Dentre os agentes antifúngicos testados, a anfotericina B foi a droga mais efetiva contra C. albicans. A freqüência, a seletividade e o nível de produção de exoenzimas pelo microorganismo sugerem a ocorrência de uma maior patogenicidade nas crianças com AIDS do que nas crianças do grupo controle

Aspectos histopatológicos e micológicos da infecção experimental de cobaias com Microsporum canis

Dermatophytosis is a zoonosis in whose etiology the dermatophyte Microsporum canis is frequently involved. The fungus can be transmitted to man by dogs and cats. In the present study, guinea pigs were experimentally inoculated with M. canis and the course of the lesions was evaluated. Inoculation resulted in lesions in 100% of the animals, with a clinical course consisting of an incubation period, an inflammatory and a phase of lesion resolution. The histopathologic evaluation of the skin biopsies revealed the presence of acanthosis, hyperkeratosis, spongiosis and marked dermal edema. M. canis spores and hyphae were detected in histologic sections stained with periodic acid-Schiff. The combination of the fluorescent dyes FD and EB permitted the adequate visualization of viable and dead fungal cells in skin fragments of guinea pigs inoculated with M. canis and the identification of the morphologic characteristics of the cells. This experimental model represents a valuable instrument for the study of the pathogenesis of dermatophytic infection with respect to the evaluation of the efficacy of antifungal drugs, and may also be used for the study of the immunology of dermatophytoses and of dermatophyte morphogenesCom frequência o dermatófito Microsporum canis está envolvido na etiologia da dermatofitose, podendo ser transmitido para o homem por cães e gatos. Neste estudo foi procedida inoculação experimental de M. canis em cobaias resultando em lesões em 100 % dos animais e o curso clínico consistiu de período de incubação, fase inflamatória e fase de resolução das lesões. O exame histopatológico de biópsias cutâneas revelou presença de infiltrado neutrofílico e edema; acantose, hiperqueratose e espongiose. Estas lesões tornaram-se menos acentuadas no 30.0 dia pós-inoculação. Esporos e hifas de M. canis foram detectadas em cortes histológicos corados com PAS (Ácido Periódico de Schiff). A combinação dos corantes fluorescentes diacetato de fluoresceína (DF) e brometo de etídio (BE), possibilitou uma adequada visualização das células fúngicas viáveis e não viáveis com evidenciação de seus caracteres morfológicos. Este modelo experimental representa um valioso instrumento para o estudo da patogênese da infecção por dermatófitos, para a avaliação da eficácia de drogas antifúngicas, podendo também ser utilizado em estudos sobre a imunologia das dermatofitoses e na determinação da morfogênese de dermatófitos

Eficácia do acaricida maleato de estanho tri-n-butílico contra ácaros de poeira em carpetes, tecidos e espuma de colchão: padronização de metodologia

The aim of this study was to determine the effectiveness of the acaricide tri-n-butyl tin maleate, industrially applied to samples of carpets, mattress foam, and fabrics used for furniture upholstery, soft toys and shoe uppers. Approximately 100 adult house dust mites of the species Dermatophagoides pteronyssinus were inoculated into a Petri dish containing the sample (a piece of carpet, mattress foam, or fabric), treated with the acaricide, randomly collected. Mite-maintenance culture medium was added on top of each sample. After one, two, three, seven and 30 days of incubation at 25 ºC and 75% relative humidity, each dish was examined using a 40X stereoscopic microscope (40X). One hundred percent acaricide effectiveness was obtained in treated materials by the end of the 30th-day postinoculation period, under optimal conditions for mite maintenance.O objetivo do presente estudo foi verificar a eficácia do acaricida maleato de estanho tri-n-butílico, aplicado industrialmente em amostras de carpetes, tecidos de revestimentos de móveis e de calçados, assim como de espumas de colchão. Aproximadamente 100 ácaros adultos da espécie Dermatophagoides pteronyssinus foram inoculados em placa de Petri contendo a amostra (pedaço de colchão, tecido ou carpete), tratada com o produto acaricida, coletados aleatoriamente. Foi acrescentado sobre a amostra, meio de cultivo para a manutenção dos ácaros. Cada placa foi examinada após 1, 2, 3, 7 e 30 dias de incubação a 25 ºC e 75% de U.R.A. (umidade relativa do ar), sob microscópio estereoscópico com 40X de aumento. O acaricida maleato de estanho tri-n-butílico apresentou 100% de eficácia acaricida após 30 dias da aplicação, em condições ótimas para a manutenção dos ácaros

Freqüência e atividade enzimática (proteinase e fosfolipase) de Candida albicans de pacientes desdentados totais, com e sem estomatite protética

The so called erithematous stomatitis is frequently observed in denture wearers, being local factors, mainly related to the presence of yeasts, considered important for its development. Having these aspects in mind, we evaluated edentulous patients with and without denture stomatitis (DS), identifying the yeasts obtained from the palate, and determining the relative level of the proteinase and phospholipase exo-enzymes produced by C. albicans. The results suggested that C. albicans was the most frequent species observed, being more prevalent in patients presenting DS, isolated or in association with other yeasts, with high expression of proteinase.A Estomatite Protética (EP) é freqüentemente observada em pacientes portadores de prótese total, sendo a presença de fungos considerada um importante fator para o seu aparecimento. Baseado neste fato, avaliamos pacientes edêntulos com e sem estomatite protética, identificando os fungos presentes, e os níveis de proteinase e fosfolipase produzidos por Candida albicans. Os resultados mostraram que C. albicans foi a espécie mais freqüente, prevalecendo em pacientes com EP. Todas as cepas de C. albicans isoladas foram fortemente positivas para proteinase, diferentemente da atividade de fosfolipase

Atividade de tri-n-butyl tin maleate em carpetes contra Staphylococcus aureus e Aspergillus niger, verificada através de duas metodologias: Zona de Inibição (ZI) e Superfície de Inibição (Impressão)

The aim of the present study was to verify the activity of the Tri-N-Butyl Tin maleate compound against Staphylococcus aureus and Aspergillus niger, after its industrial application in 40 samples of carpets of different materials (polypropylene, polyester, polyamide and wool). The qualitative assays were performed through two methodologies: Inhibition Halo (HZ) and Inhibition of Surface (Print). The carpet with the product inhibited 100% of bacterial (Staphylococcus aureus) and fungi (Aspergillus niger) growth, under the conditions of this study. The microbial inhibition was higher in upper portion of carpets. The methodologies employed appear to be adequate to test the bactericide and fungicide activities of the Tri-N-Butyl Tin maleate. The print methodology confirmed the results obtained by the inhibition zone assay. Further studies using the same methodologies are needed to confirm our results.O objetivo do presente estudo foi verificar a atividade do composto maleato de estanho tri-n-butílico contra Staphylococcus aureus e Aspergillus niger, após sua aplicação industrial em 40 amostras de carpetes de diferentes materiais (polipropileno, poliéster, poliamida e lã). Os ensaios qualitativos foram realizados através de duas metodologias: Zona de Inibição (ZI) e Superfície de Inibição (Impressão). Os carpetes tratados com o produto apresentaram 100% de inibição de crescimento bacteriano (Staphylococcus aureus) e fúngico (Aspergillus niger), sob as condições desse estudo. A inibição de crescimento microbiano foi mais elevada na porção superior dos carpetes. As metodologias empregadas parecem ser adequadas para testar a atividade bactericida e fungicida do maleato de estanho tri-n-butílico. A metodologia de impressão confirmou os resultados obtidos no ensaio de zona de inibição. Estudos futuros utilizando as mesmas metodologias são necessários para confirmação destes dados

Ringworm caused by Microsporum nanum in a swine breeding

The authors present 7 cases of ringworm in animals from São Paulo state Landrace swine breeding. Diagnosis was established by direct microscopic examination and culture of the material obtained by scrapping of the lesions. Ringworn caused by Microsporum nanum was characterized.Os autores apresentam casos de dermatite micótica em sete animais de uma criação de suínos de raça Landrace, no Município de São Roque, Estado de São Paulo. Todos os animais apresentavam no tórax, lesões cutâneas, irregulares, de aspecto ligeiramente rugoso, às vezes crostosas, de tonalidade castanha, circundadas por acentuado halo hiperêmico. O diagnóstico estabeleceu-se após raspagem das lesões, seguindo-se exame direto e cultura do material, concluindo-se por dermatomicose causada por Microsporum nanum

Ocorrência de fungos em lesões superficiais de cães na cidade de São Paulo, Brasil

It is presented the result of a mycological study performed in 212 dogs which showed superficial tesions clinically related to dermatomycosis, during the period of January till December, 1986. Through the direct microscopic examination and cultures isolation from the specimens, there were identified the following etiologic agents: Malassezia pachydermatis (49,5%); Microsporum canis (30,0%); M. gypseum (4,7%); Trichophyton mentagrophytes (0,9%). Several different genera were identified in low frequencies as follows: Candida; Trichosporon; Torulopsis; Geotrichum; Cephalosporium; ScopuI ariopsis and a dematiaceous fungi. The highest frequency of dermatomycosis occurred in the group of dogs which had less than 11 months old.Foram estudados 212 casos de cães com suspeita clinica de dermatomicose, no período de janeiro a dezembro de 1986. Deste total investigado, foram diagnosticados, através de exame microscópico direto e cultivo, 107 casos de dermatomicoses (50,5%). Malassezia pachydermatis foi o agente predominante (43,5%) seguido dos dermatófitos Microsporum canis (30,0%), M. Gypseum (4,7%), Trichophyton mentagrophytes (0,9%). Outros fungos como Candida sp, Trichosporon sp, Torulopsis sp, Geotrichum sp, Cephalosporium sp, Scopularopsis sp e fungos dematáceos foram isolados, sendo discutível sua participação na etiologia primária das lesões. De acordo com a faixa etária, a maior prevalência ocorreu no grupo de até 11 meses e com referência ao sexo, não houve predominância significativa

Importance of Yeasts in Oral Canine Mucosa

Dentistry science is a new specialty in veterinary medicine that has been growing in recent years, accompanied by the development of professionals who seek to improve the quality of life of pets. Cases related to problems in the oral cavity have gained significant importance in the medical clinic of professionals who treat small animals. Due to lack of professional knowledge or due to animal behavioral problems, such as aggressiveness, the anamnesis of the oral cavity is not performed most of the time, which ends up delaying the diagnosis of the pathology. In addition, an animal with a problem in the oral cavity may take years to show signs of the disease. In general, animals have an oral microbiota composed of various species of fungi, which, under specific conditions, can change from saprophytes to pathogens, compromising their health. Thus, the pre-knowledge of potentially pathogenic yeasts belonging to oral microbiota of dogs and their susceptibility profile compared to the main drugs used in antifungal therapy, is of fundamental importance as it ensures a clinical auxiliary support for the diagnosis and treatment of most diseases of the oral cavity