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In the UK, there are up to 3,000 cancer patients who have undergone total laryngectomy and use voice prostheses (VPs), for speech rehabilitation. VPs are inserted between the eosphagus and trachea to provide a 'voice' but, as with other semi-in-dwelling devices, such as nasal and gastric tubes, they invariably fail due to occlusion by microbial biofilms. The requirement for frequent replacement is financially costly to the NHS and impacts patient well-being. Replacement frequency varies by patient, from 7 weeks to 6 months but the reasons for this variation are not clearly understood. By designing and implementing a study of microbial colonisation of VPs and oral rinse samples submitted by 14 Speech and Voice Clinic patients over 13 months, this study explored whether specific microbes or patient factors, including the use of antacids, antibiotics and nystatin, along with denture-use, were potential predictors of device longevity. Focussing on the role of the commonly isolated fungi, we sought to understand the role of diet or the presence of the bacterium, S. aureus, in biomass accumulation. We also asked whether biofilm regulation pathways are shared across the fungi and could constitute a potential target for therapeutics. Microbial isolation from 66 VPs showed the predominant species as described in previous studies, but each participant had a unique profile which persisted over time, with half of the microbes originating from the oral flora. Clinic-based participants experienced fewer problems, primarily due to the device type used, and carried fewer species of Gram negative bacteria than the long term users. Statistical analysis showed that patient medication influences biofilm composition and dietary sugars differentially affect biomass formation. In vitro experiments showed that the ability to treat Candida biofilms with nystatin was improved in the presence of S. aureus. Expression analysis showed that regulation of biofilms in C. parapsilosis was the closest to that of C. albicans but that the extent of protein homology to C. albicans regulators was not a predictor of expression levels. It is therefore unlikely that a single therapeutic could be developed to target biofilm gene regulation. This work provides new insights into the complexity of biofilm formation in voice prosthesis users but reveals associations between microbes, diet, prosthesis type and medications that might be used to advise patients and help to reduce the stress and cost of frequent device failure and replacement.

Orientador: Francisco Benedito Teixeira Pessine / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-14T22:28:32Z (GMT). No. of bitstreams: 1 Brescansin_EdeilzaGomes_D.pdf: 1646931 bytes, checksum: 9e5e045b99495a199511f36621650953 (MD5) Previous issue date: 2006 / Resumo: No presente trabalho, buscamos desenvolver formulação lipossomal sistêmica de nistatina (NYS) com o propósito de aplicações futuras na terapêutica de micoses sistêmicas, que tanto afligem indivíduos imunodeprimidos. Na primeira parte do projeto caracterizamos o fármaco através de análises térmicas (TGA e DSC), análises espectroscópicas (IV, UV e fluorescência), teste de solubilidade, avaliação da umidade segundo o método de Karl-Fischer e coeficiente de partição octanol/meio aquoso. Na segunda parte do trabalho procuramos desenvolver e otimizar formulações lipossomais, onde o fármaco apresentasse maior estabilidade química. Foram preparadas formulações lipossomais pelo método do filme lipídico que foram analisadas por HPLC. As preparações passaram por processo de diminuição de tamanho e separação entre fármaco livre e encapsulado. A terceira e última fase do projeto consistiu da caracterização de duas preparações, através de análises do raio hidrodinâmico, determinação da carga de superfície das partículas (potencial zeta), teor de fosfolipídios totais (teor de fosfato), eficiência e avaliação da encapsulação por análises de HPLC, anisotropia e supressão de fluorescência. Ainda na fase de caracterização investigamos a atividade biológica in vitro, destas formulações, pelo teste de susceptibilidade. As preparações foram desafiadas contra leveduras e dermatófitos. Pela seleção e otimização das formulações desenvolvidas concluímos que a melhor formulação foi a que apresenta uma composição de 70 % de Epikuron 200 SH; 20 % de Colesterol; 10 % de Diestearoilfosfatidilglicerol, 1,3 % de 2,6 - bis (1,1-dimetil) - 4 - metil fenol (BHT) e 7 % de NYS. Duas preparações foram caracterizadas L1 (hidratada a 55°C) e L2 (hidratada a 60°C). Os resultados para anisotropia e supressão de fluorescência evidenciam a encapsulação do fármaco nas preparações estudadas, tanto na bicamada lipídica quanto na superfície dos lipossomas. Verificamos também que L2 apresentou menor polidisperdidade de seu raio hidrodinâmico, maior carga de superfície e maior eficiência de encapsulação, evidenciando ser L2 a preparação, físico-quimicamente, mais estável. Todavia, a preparação L1 mostrou, após sonicação, atividade biológica in vitro maior que L2. Estes resultados podem refletir a possível degradação do fármaco, quando aquecido a 60°C. / Abstract: This study was designed to develop liposomal formulations containing Nystatin (NYS), looking forward its future applications in systemic mycosis therapy, which often affect immunodepressed individuals. In the first part of the project, the drug was characterized by means of thermal analyses (TGA and DSC), IR, UV/V and fluorescence spectroscopies, solubility tests, humidity contents evaluation (Karl-Fischer method) and octanol-water partition coefficient. In the second part of the study, liposomal formulations were developed and optimized, in which the drug presented improved chemical stability. Liposomal formulations were prepared by the dry lipid film hydration method and were analyzed by HPLC. The vesicles were submitted to the processes of size reduction and separation of non encapsulated drug. The last part of the project consisted in the characterization of the two formulations by means of analysis of the is hydrodynamic radius; determination of the particles superficial charge (zeta-potential); total phospholipids content (phosphate); degree of NYS with encapsulation by HPLC; degree of anisotropy and fluorescence quenching of NYS. Still during the characterization phase, the in vitro biological activity of the formulations was investigated by means of susceptibility tests. The formulations were challenged against some yeasts and filamentous fungi. Conclusions pointed that the best formulation was the one which presented in its compositions 70% Epikuron 200 SH, 20% Cholesterol, 10 % Distearoylphosphatidylglycerol, 1.3 % 2,6 - bis (1,1-dimethylethyl) - 4 - methylphenol (BHT) and 7 % NYS. Two formulations were characterized: L1 (hydrates at 55°C) and L2 (hydrated at 60°C). Results regarding the degree of anisotropy and fluorescence quenching evidenced by NYS encapsulation at the liposomal lipid bilayers. Moreover, it was observed that L2 presented lower polydispersity in size distribution, higher superficial load and higher encapsulation effectiveness, i.e. L2 presented higher physico-chemical stability. Nevertheless the L1 preparation showed, after sonication, higher biological activity in vitro than L2, which might reflect possible thermal degradation of NYS when heated to 60°C. / Doutorado / Físico-Química / Doutor em Ciências

Orientador: Denise Madalena Palomari Spolidorio / Resumo: Os sistemas precursores de cristal líquido associados aos extratos vegetais e compostos fitoquímicos abrem novas perspectivas para prevenção e controle eficiente de doenças infecciosas fúngicas. Os objetivos deste estudo foram: I) avaliar o efeito sinérgico da associação do terpinen-4-ol (t-4-ol) com a nistatina (nis); II) avaliar na forma de cristal líquido, a propriedade antifúngica do t-4-ol e possível sinergismo com a nis; III) avaliar a citotoxicidade do t-4-ol em células orais normais imortalizadas (NOK) e verificar se o t-4-ol interfere na adesão de Candida albicans sobre células orais. Assim, foi definida a Concentração Inibitória Mínima (CIM) e a Concentração Fungicida Mínima (CFM) do t-4-ol sobre isolados clínicos de C. albicans (Genotipagem A e B) e cepa SC 5314, empregando-se o método de microdiluição em caldo. Biofilmes foram preparados usando o modelo de placa de microtitulação estática e quantificados por metodologia colorimétrica do ensaio de redução de sal de tetrazólio (XTT). Os mesmos testes foram aplicados para avaliar o t-4-ol e nis na forma de cristal líquido. Adicionalmente, as células foram cultivadas em meio de cultura Dulbecco ́s Modified Eagle ́s Medium (DMEM) suplementado com 10% de soro fetal bovino e 1% de penicilina, estreptomicina e glutamina e mantidas em incubadora a 37o C em 5% de CO2. A citotoxicidade sobre linhagem de células NOK foi avaliada por citometria de fluxo e foi realizado o teste de co-cultura, para verificar a interferência do t... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The liquid crystal precursor systems associated with plant extracts and phytochemical compounds open new perspectives for efficient prevention and control of infectious fungal diseases. The objectives of this study were: I) to evaluate the synergistic effect of the combination of terpinen-4-ol (t-4-ol) with nystatin (nys); II) to evaluate in liquid crystal form the antifungal property of t-4-ol and possible synergism with nys; III) to evaluate the cytotoxic potential of t-4-ol in normal immortalized oral cells (NOK) and to verify whether t-4-ol interferes with the adhesion of Candida albicans to oral cells. Thus, the Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (CFM) of t-4-ol on clinical isolates of C. albicans (Genotype A and B) and strain SC 5314 were determined using the microdilution method in broth. Biofilms were prepared using the static microtiter plate model and quantified by colorimetric methodology of the tetrazolium salt reduction assay (XTT). The same tests were applied to evaluate t-4-ol and nys in liquid crystal form. In addition, the cells were cultured in Dulbecco's Modified Eagle's Medium (DMEM) medium supplemented with 10% fetal bovine serum and 1% penicillin, streptomycin and glutamine and maintained in an incubator at 37 ° C in 5% CO2 . Linear cytotoxicity of NOK cells was assessed by flow cytometry and the coculture test was performed to verify the interference of t-4-ol on Candida albicans adhesion on oral cells (NOK). Can... (Complete abstract click electronic access below) / Doutor

Objectives: Candida glabrata is the second most common cause of oral candidiasis, second only to C. albicans. Incidence of antifungal resistance has shown a steady increase for C. glabrata. Iron has shown to modulate C. albicans pathogenesis and affect drug-susceptibility. Here, we assess the effect of iron on the growth, antifungal-susceptibility, biofilms, and cell wall of C. glabrata.Methods: Growth, minimal inhibitory concentration (MIC), and biofilm experiments were conducted using 96-well polystyrene plates. Yeast Nitrogen Base medium was used for growth experiments. Cultures of C. glabrata and C. albicans were grown over two nights in respective media containing varying iron concentrations. Rosewell Park Memorial Institute medium was used for MIC and biofilm experiments. Serial dilution was performed to obtain desired concentrations of antifungal drugs. For all experiments, growth was assessed at OD600nm over 24 hours using BioTek Synergy Multi Mode Reader. Paraformaldehyde treated cells and specific stains were used for cell wall studies. Results: Growth of C. glabrata declined significantly below 5μM iron, while C. albicans continued to grow at decreasing iron concentrations, up to 0.5μM. MIC experiments revealed 1.562μM, 1.562μM, and 4μM, as the MIC for Deferasirox, Nystatin, and Fluconazole, respectively. Drug synergy experiments revealed a 128-fold reduction in the amount of Nystatin and Fluconazole needed, with the addition of 1/8th of Deferasirox concentration. The biofilm experiments were inconclusive and the cell wall studies showed decreased levels of mannan, chitin, and an increased β-glucan exposure in high iron conditions. Conclusion: C. glabrata is more sensitive to alterations in environmental iron when compared to C. albicans. Drug synergy experiments underscore the importance of Deferasirox in lowering the MICs of Nystatin or Fluconazole. This can allow use of classical antifungals at lower doses, thereby limiting their side effects. Cell wall studies discuss the effect of iron on the virulence of the C. glabrata. / Oral Biology

We have applied an electrophysiologic technique (Reuss L.(1985) Proc. Natl. Acad. Sci. USA 82, 6014) to measure changes in steady-state hepatocyte volume during osmotic stress. Hepatocytes in mouse liver slices were loaded with tetramethylammonium ion (TMA+) during transient exposure of cell to nystatin. Intracellular TMA+ activity (αiTMA) was measured with TMA+ -sensitive, double-barrelled microelectrodes. Loading hepatocytes with TMA+ did not change their membrane potential (Vm), and under steady-state conditions αiTMA remained constant over 4 min in a single impalement. Hyperosmotic solutions (50, 100 and 150 mM sucrose added to media) and hyposmotic solutions (sucrose in media reduced by 50 and 100 mM) increased and decreased αiTMA, respectively, which demonstrated transmembrane water movements. The slope of the plot of change in steady-state cell water volume, [(αiTMA)O/(αiTMA)4min] - 1, on the relative osmolality of media, (experimental mosmol/control mosmol) -1, was less than predicted for a perfect osmometer. Corresponding measurements of Vm showed that its magnitude increased with hyposmolality and decreased with hyperosmolality. When Ba2+ (2 mM) was present during hyposmotic stress of 0.66 × 286 mosmol (control), cell water volume increased by a factor of 1.44 ± 0.02 compared with that of hyposmotic stress alone, which increased cell water volume by a factor of only 1.12 ± 0.02, P< 0.001. Ba2+ also decreased the hyperpolarization of hyposmotic stress from a factor of 1.62 ± 0.04 to 1.24 ± 0.09, P < 0.01. We conclude that hepatocytes partially regulate their steady-state volume during hypo- and hyperosmotic stress. However, volume regulation during hyposmotic stress diminished along with hyperpolarization of Vm in the presence of the K+ -channel blocker, Ba2+. This shows that variation in Vm during osmotic stress provides an intercurrent, electromotive force for hepatocyte volume regulation.

Objectifs: Le Nystatin est un antibiotique efficace pour le traitement d’otomycose. Bien que sa sécurité au niveau de l’oreille externe soit bien établie, son utilisation n’est pas recommandée lorsqu’il y a une perforation tympanique. L’objectif de cette étude est d’évaluer le potentiel ototoxique du Nystatin lorsque celui-ci est appliqué directement au niveau de l’oreille moyenne. Méthodes: Nous avons fait une étude expérimentale avec 18 cochons d’Indes de souche Hartley que nous avons divisés en deux groupes. En exposant l’oreille moyenne de chaque animal au Nystatin (groupe I) ou à la néomycine (groupe II) et chaque oreille controlatérale à une solution physiologique (NaCl), la fonction auditive a été évaluée avec un test de potentiels évoqués auditif du tronc cérébral avant et après les injections. Une étude par microscopie électronique a permis une comparaison histologique de l’état des cellules ciliées cochléaires entre les 2 groupes. Résultats: Les pertes auditives moyennes du groupe « Nystatin » étaient de 13.0 dB et comparables aux pertes moyennes observées dans les oreilles ayant été injectées avec du NaCl (4.0 dB dans le groupe I et 15.1 dB dans le groupe II). Le groupe de contrôle « néomycine » a subi une perte auditive moyenne de 39.3 dB, ce qui représente une différence cliniquement et statistiquement significative (p<0.001). L’étude histologique avec une microscopie à balayage électronique a démontré une conservation de l’architecture des cellules ciliées cochléaires dans les groupe Nystatin et NaCl. La néomycine a causé une destruction marquée de ces structures. Conclusions: Le Nystatin ne provoque pas d’atteinte auditive ni de destruction des cellules ciliées externes après injection directe dans l’oreille moyenne chez le cochon d’Inde. / Objective: Nystatin is an effective topical antifungal agent widely used in the treatment of otomycosis. Though it is safe for external ear use, current recommendations are to avoid its use in cases of tympanic membrane perforation. The objective of our study was to test the security of Nystatin when applied directly to the middle ear of a guinea pig model. Methods: We performed an experimental study with 18 Hartley guinea pigs that were divided into two groups. Exposing middle ears from one group to Nystatin (group I) and from the other to the ototoxic neomycin (group II), we compared results of auditory brainstem response (ABR) testing at three intervals during the study. Each animal’s contralateral ear was injected with a physiological solution (NaCl). At the end of the study, we performed a histological analysis of the animals’ cochleae using a scanning electron microscope. Results: Average hearing loss in the Nystatin group was 13.0 dB which was similar to the results obtained in the NaCl-exposed ears (4.0 dB in group I and 15.1 dB in group II). Average hearing loss in the neomycin group was 39.3 dB, which represents a clinically significant difference (p<0.001). Scanning electron microscope evaluation revealed intact cochlear hair cell architecture in the Nystatin and normal saline groups, compared to important destruction in the neomycin group. Conclusion: Nystatin does not cause hearing impairment or cochlear hair cell damage when exposed directly to the middle ear of a guinea pig model.

Objectifs: Le Nystatin est un antibiotique efficace pour le traitement d’otomycose. Bien que sa sécurité au niveau de l’oreille externe soit bien établie, son utilisation n’est pas recommandée lorsqu’il y a une perforation tympanique. L’objectif de cette étude est d’évaluer le potentiel ototoxique du Nystatin lorsque celui-ci est appliqué directement au niveau de l’oreille moyenne. Méthodes: Nous avons fait une étude expérimentale avec 18 cochons d’Indes de souche Hartley que nous avons divisés en deux groupes. En exposant l’oreille moyenne de chaque animal au Nystatin (groupe I) ou à la néomycine (groupe II) et chaque oreille controlatérale à une solution physiologique (NaCl), la fonction auditive a été évaluée avec un test de potentiels évoqués auditif du tronc cérébral avant et après les injections. Une étude par microscopie électronique a permis une comparaison histologique de l’état des cellules ciliées cochléaires entre les 2 groupes. Résultats: Les pertes auditives moyennes du groupe « Nystatin » étaient de 13.0 dB et comparables aux pertes moyennes observées dans les oreilles ayant été injectées avec du NaCl (4.0 dB dans le groupe I et 15.1 dB dans le groupe II). Le groupe de contrôle « néomycine » a subi une perte auditive moyenne de 39.3 dB, ce qui représente une différence cliniquement et statistiquement significative (p<0.001). L’étude histologique avec une microscopie à balayage électronique a démontré une conservation de l’architecture des cellules ciliées cochléaires dans les groupe Nystatin et NaCl. La néomycine a causé une destruction marquée de ces structures. Conclusions: Le Nystatin ne provoque pas d’atteinte auditive ni de destruction des cellules ciliées externes après injection directe dans l’oreille moyenne chez le cochon d’Inde. / Objective: Nystatin is an effective topical antifungal agent widely used in the treatment of otomycosis. Though it is safe for external ear use, current recommendations are to avoid its use in cases of tympanic membrane perforation. The objective of our study was to test the security of Nystatin when applied directly to the middle ear of a guinea pig model. Methods: We performed an experimental study with 18 Hartley guinea pigs that were divided into two groups. Exposing middle ears from one group to Nystatin (group I) and from the other to the ototoxic neomycin (group II), we compared results of auditory brainstem response (ABR) testing at three intervals during the study. Each animal’s contralateral ear was injected with a physiological solution (NaCl). At the end of the study, we performed a histological analysis of the animals’ cochleae using a scanning electron microscope. Results: Average hearing loss in the Nystatin group was 13.0 dB which was similar to the results obtained in the NaCl-exposed ears (4.0 dB in group I and 15.1 dB in group II). Average hearing loss in the neomycin group was 39.3 dB, which represents a clinically significant difference (p<0.001). Scanning electron microscope evaluation revealed intact cochlear hair cell architecture in the Nystatin and normal saline groups, compared to important destruction in the neomycin group. Conclusion: Nystatin does not cause hearing impairment or cochlear hair cell damage when exposed directly to the middle ear of a guinea pig model.

Magister Chirurgiae Dentium - MChD (Oral Medicine and Periodontics) / Candida species are frequently isolated from oral mucosal surfaces of healthy individuals and is the most common genus responsible for up to 75% of all candidal infections. The most common problems associated management of oral candidiasis are antifungal drug resistance and side effects Natural medicine is an emerging field and is being explored to overcome drug resistance and to reduce side effects. Gymnemagenin (will be known as Gymnemic acid; GA) is a purified extract from Gymnema sylvestre, a slow growing, perennial, medicinal plant found in Central and Western India, Tropical Africa and Australia is regarded as one of the plants with potent antimicrobial and antifungal activity.

<p>Syftet med detta projekt var att undersöka om det är möjligt att använda en fungicid vid odling av celler från Oncidium crispum, för att slippa kontaminering av mykorrhizasvamp. Kontaminering från denna sorts svamp har i tidigare försök varit ett stort promlem. I undersökningen användes fungiciden Nystain. Ett första försök gjordes för att testa om Nystatin hade effekt på den aktuella svampen. På näringsmedium fick hyfer från mykorrhizasvampen växa mot ett filterpapper indränkt i Nystatinlösning med olika koncentrationer. Som kontroll användes filterpapper indränkta i vatten och 20 % etanol. Efter 72 h mättes hur nära svampen växt pappret eller om den växt över pappret. Det kunde konstateras att Nystatin vid den starkaste koncentrationen hindrade svampens framväxt. Där stannade svampen innan pappret i större utsträckning än hos de lägre koncentrationerna. Av första försöket drogs därför slutsatsen att Nystatin hämmar mykorrhizasvampen. I ett andra försök doppades explantat från Oncidium crispum i en lösning av Nystatin i olika koncentrationer, som kontroll användes vatten och 20 % etanol. Explantaten lades på MS-medium med hormonerna auxin och cytokinin. Vid den starkaste koncentrationen av Nystatin hämmades tillväxten av svamphyfer fullständigt. Däremot kunde ingen kallustillväxt urskiljas hos något av explantaten. Som kontroll för att försäkra sig om att Nystainet inte påverkade växtmaterialet negativt gjordes andra delen av försöket även med Stapelia grandiflora, ett växtmaterial som är känt för att lätt kunna bilda kallus. Kallustillväxten var fullständig hos kontrollen med vatten, hos de övriga lösningarna var kallustillväxten tyvärr mycket begränsad.</p> / <p>The purpose of this project was to examine if it’s possible to use a fungicide when growing cells from Oncidium crispum, to avoid the contamination of mycorrhizafungus. The contamination from this kind of fungus has been a big problem in earlier experiments. The fungicide used in the experiment was Nystatin. In a first experiment the effect of Nystatin against the mycorrhizafungus was tested. On a nutrient medium hyphae from the mycorrhizafungus were growing towards a paper disc soaked with a solution of Nystatin in different concentration. Paper discs soaked with water and 20 % ethanol were used as a reference. After 72 h it was measured how close the hyphae has got to the paper disc or if it had grown over the paper. It was established that the strongest concentration of Nystatin inhibited the growth of hyphae, in this concentration it stopped growing before it came to the paper disc in a greater extent then by the other concentrations. Therefore the conclusion was drawn, that Nystatin inhibits growth of the mycorrhizafungus. In a second experiment explants from Oncidium crispum were dipped in a solution of Nystatin in different concentrations, water and 20 % ethanol was used as a reference. The explants were placed on a MS-medium with the hormones auxin and cytokinin. By the strongest concentration of Nystatin there was no growth of hyphae. Callus formation couldn’t be distinguished by any of the explants. To make sure that Nystatin did not have a bad influence on the plant material the second part of the experiment was also performed on Stapelia grandiflora, a plant material that is known for its ability to form callus. In the reference with water the callus formation was complete, but in the other solutions the callus formation was very limited.</p>