Use of scanning electron microscopy in the cochlea of guinea pigs / Microscopia eletrônica de varredura em cócleas de cobaias

Abstract Introduction: The use of electron microscopy in the study of the inner ear has allowed us to observe minute details of the hair cells, especially in ototoxicity studies; however, the preparation of this material is a difficult and delicate task. In an attempt to simplify the handling of these materials, two agents, toluidine blue and ethylenediamine tetra-acetic acid were tested, in addition to the elimination of osmium tetroxide during the preparation of albino guinea pig cochleae. We also tested the applicability of these methodologies in an ototoxicity protocol. Objective: To verify the quality of the images obtained with and without the use of ethylenediamine tetra-acetic acid, toluidine blue and osmium tetroxide in the preparation of cochleae of albino guinea pigs for the scanning electron microscopy. Methods: Three groups of cochleae were used. In Group 1, 10 cochleae were prepared with the usual methodology, dissecting the optical capsule without decalcification and using osmium tetroxide as a post-fixative agent. In Group 2, we prepared 10 cochleae decalcified with ethylenediamine tetra-acetic acid, injecting toluidine blue in the endolymphatic space to facilitate the identification of the organ of Corti. In Group 3, we used 4 cochleae of guinea pigs that received 3 doses of cisplatin (7.5 mg/kg, D1-D5-D6), two prepared according to the methodology used in Group 1 and two with that used in Group 2. Scanning electron microscopy images were obtained from the organ of Corti region of the basal turn of each cochlea. Results: The organ of Corti was more easily identified with the use of toluidine blue. The dissection of the cochlea was more accurate in the decalcified cochleae. The quality of the images and the preservation of the organ of Corti obtained with the two methodologies were similar. Conclusion: The proposed modifications resulted in images of similar quality as those observed using the traditional methodology.

Resumo Introdução: O emprego da microscopia eletrônica no estudo da orelha interna permitiu observar detalhes minuciosos das células ciliadas especialmente em estudos de ototoxicidade. Entretanto, o preparo desse material é trabalhoso e delicado. Para simplificar a manipulação desses materiais, testou-se o uso de dois agentes, azul de toluidina e ácido etilenodiamino tetra-acético, além da retirada do tetróxido de ósmio na preparação de cócleas de cobaias albinas. Testamos também a aplicabilidade dessas metodologias em um protocolo de ototoxicidade. Objetivo: Verificar a qualidade das imagens obtidas com e sem o uso de ácido etilenodiamino tetra-acético, azul de toluidina e tetróxido de ósmio na preparação de cócleas de cobaias albinas para a microscopia eletrônica de varredura. Método: Foram utilizados três grupos de cócleas. No Grupo 1 preparou-se 10 cócleas com a metodologia usual, dissecando a cápsula ótica sem descalcificac¸ão e utilizando tetróxido de ósmio como pós-fixador. No Grupo 2 preparamos 10 cócleas descalcificadas com ácido etilenodiamino tetra-acético, injetando azul de toluidina no espac¸o endolinfático para facilitar a identificação do órgão de Corti. No Grupo 3 utilizamos 4 cócleas de cobaias que receberam 3 doses de cisplatina (7,5 mg/kg, D1-D5-D6), duas preparadas com a metodologia do Grupo 1 e duas com a do Grupo 2. Foram obtidas imagens da microscopia eletrônica de varredura da região do órgão de Corti do giro basal de cada cóclea. Resultados: O órgão de Corti foi mais facilmente identificado com o azul de touidina. A dissecção da cóclea foi mais precisa nas cócleas descalcificadas A qualidade das imagens e a preservac¸ão do órgão de Corti obtidas com as duas metodologias foi similar. Conclusão: As modificações propostas resultaram em imagens de qualidade similar as observadas com o uso da metodologia tradicional.

Ultrafast Toluidine Blue Staining for Rapid On-Site Evaluation of Cytological Smears.

Rapid on-site evaluation (ROSE) is one of cytopathology's "unique selling propositions." The quality, speed, and ease of handling of the staining used is a critical factor for the efficacy of the ROSE procedure. Here, we describe a modification of rapid toluidine blue staining that can be performed within 25 s, provides excellent nuclear morphology, and is compatible with subsequent Papanicolaou staining of the slides. Furthermore, exposure to hazardous chemicals is minimized, as no organic solvents other than the alcohol-based fixative and glycerin for temporary mounting and coverslipping are required. We have used this protocol successfully in our ROSE practice and have not observed any discrepancies between toluidine blue- and permanent Papanicolaou-stained slides.

CHROMOENDOSCOPY USING TOLUIDINE BLUE PLUS LUGOL'S SOLUTION FOR EARLY DIAGNOSIS OF ESOPHAGEAL PREMALIGNANT LESIONS AND SUPERFICIAL NEOPLASMS IN HIGH-RISK PATIENTS.

BACKGROUND: Esophageal cancer is the eighth most common cancer. The prognosis is bleak in patients with advanced stages. Patients with early disease have a better prognosis than those with advanced stage. There are several techniques for the screening of premalignant and superficial lesions including chromoendoscopy. OBJECTIVE: This article aimed to determine the effectiveness of chromoendoscopy with toluidine blue combined with Lugol's solution for diagnosis of esophageal premalignant and superficial neoplastic lesions in high risk patients. METHODS: Routine white light upper endoscopy was performed. Toluidine blue was sprayed from the gastroesophageal junction to 20 cm of the dental arch. Then the uptake dye areas were characterized. Later Lugol's solution was sprayed. Areas with less-intense staining were characterized. Biopsy of the toluidine blue capturing areas and areas with less-intense staining of Lugol's solution were taken. In the cases where lesions were not evidenced after application of dyes, biopsies four quadrants of the esophageal mucosa were taken. The samples were evaluated by a digestive pathologist. RESULTS: Barrett's esophagus was the most common premalignant lesion and the early neoplastic lesion was adenocarcinoma with a sensitivity of 100%, specificity 85.7%, positive predictive value 30%, negative predictive value 100%, positive likelihood ratio 7 negative likelihood ratio 0. CONCLUSION: Chromoendoscopy with toluidine blue combined with Lugol's solution is a useful tool in the screening of esophageal premalignant lesions and superficial neoplasms.

Utilização da cromoendoscopia com azul de toluidina mais solução de Lugol para diagnóstico precoce de lesões pré-malignas esofágicas e neoplasias superficiais em pacientes de alto risco / Chromoendoscopy using toluidine blue plus lugol's solution for early diagnosis of esophageal premalignant lesions and superficial neoplasms in high-risk patients

ABSTRACT BACKGROUND: Esophageal cancer is the eighth most common cancer. The prognosis is bleak in patients with advanced stages. Patients with early disease have a better prognosis than those with advanced stage. There are several techniques for the screening of premalignant and superficial lesions including chromoendoscopy. OBJECTIVE: This article aimed to determine the effectiveness of chromoendoscopy with toluidine blue combined with Lugol's solution for diagnosis of esophageal premalignant and superficial neoplastic lesions in high risk patients. METHODS: Routine white light upper endoscopy was performed. Toluidine blue was sprayed from the gastroesophageal junction to 20 cm of the dental arch. Then the uptake dye areas were characterized. Later Lugol's solution was sprayed. Areas with less-intense staining were characterized. Biopsy of the toluidine blue capturing areas and areas with less-intense staining of Lugol's solution were taken. In the cases where lesions were not evidenced after application of dyes, biopsies four quadrants of the esophageal mucosa were taken. The samples were evaluated by a digestive pathologist. RESULTS: Barrett's esophagus was the most common premalignant lesion and the early neoplastic lesion was adenocarcinoma with a sensitivity of 100%, specificity 85.7%, positive predictive value 30%, negative predictive value 100%, positive likelihood ratio 7 negative likelihood ratio 0. CONCLUSION: Chromoendoscopy with toluidine blue combined with Lugol's solution is a useful tool in the screening of esophageal premalignant lesions and superficial neoplasms.

RESUMO CONTEXTO: O câncer de esôfago é o oitavo câncer mais comum. O prognóstico é sombrio em pacientes com estágios avançados. Pacientes com doença precoce têm um melhor prognóstico do que aqueles com estágio avançado. Existem várias técnicas para a triagem de lesões pré-malignas e superficiais, incluindo cromoendoscopia. OBJETIVO: Este artigo objetivou determinar a efetividade da cromoendoscopia com azul de toluidina combinada com a solução de Lugol para o diagnóstico de lesões neoplásicas pré-malignas e superficiais esofágicas em pacientes de alto risco. MÉTODOS - A endoscopia de luz branca de rotina foi realizada de forma rotineira. O azul do toluidina foi pulverizado desde a junção gastroesofágica até 20 cm da arcada dentária. As áreas impregnadas pela tintura da tomada foram então caracterizadas. Mais adiante a solução de Lugol foi pulverizada. Áreas com coloração menos intensa foram caracterizadas. Foram realizadas biópsias das áreas de captura de azul de toluidina e áreas com coloração menos intensa da solução de Lugol. Nos casos onde as lesões não foram evidenciadas após a aplicação das tinturas, foram feitas biópsias em quatro quadrantes da mucosa esofágica. As amostras foram avaliadas por um patologista especializado. RESULTADOS: O esôfago de Barrett foi a lesão pré-maligna mais frequente e a lesão neoplásica precoce foi adenocarcinoma com sensibilidade de 100%, especificidade de 85,7%, valor preditivo positivo de 30%, valor preditivo negativo 100%, razão de verossimilhança positiva 7 e razão de verossimilhança negativa 0. CONCLUSÃO: A cromoendoscopia com azul de toluidina combinada com a solução de Lugol é uma ferramenta útil na triagem de lesões pré-malignas esofágicas e neoplasias superficiais.

A Standardized Method of Applying Toluidine Blue Metachromatic Staining for Assessment of Chondrogenesis.

OBJECTIVES: Staining with toluidine blue is a well-established procedure for the histological assessment of cartilaginous- and chondrogenic-differentiated tissues. Being a cationic dye, toluidine blue staining visualizes proteoglycans in a tissue because of its high affinity for the sulfate groups in proteoglycans. It is generally accepted that metachromatic staining with toluidine blue represents cartilaginous matrix and that the degree of positive staining corresponds with the amount of proteoglycans. DESIGN: Articular cartilage and pellets of chondrocytes or bone marrow stromal cells were analyzed with a standardized staining procedure for toluidine blue. RESULTS: In the present study, we illustrate why such an assumption is invalid unless a detailed description of the procedure and/or reference to a detailed published method are provided. This is because the staining specificity and intensity depend, as we have shown, on the pH of the staining solution, the use of dehydration, and on staining time. CONCLUSIONS: We can, therefore, suggest a well-controlled standardized protocol for toluidine blue staining, which provides an easy and simple selective staining technique for the assessment of cartilage tissue and proteoglycan development in chondrogenic differentiation. If this procedure is not used, then investigators must provide sufficient technical information concerning the staining protocol to allow an assessment of the validity of the staining results.

Chitosan-based mucoadhesive gel for oral mucosal toluidine blue O delivery: The influence of a non-ionic surfactant.

Photodynamic therapy (PDT) has been successfully employed in the treatment of oral cancer. Toluidine blue O (TBO) is a photosensitizer (PS) that has exhibited remarkable photocytotoxicity in a variety of tumour cells; however, its physicochemical properties, as well as the physicochemical properties of oral mucosa, prevent the drug from reaching the target site at a therapeutic concentration. The aim of this study was to evaluate the influence of Tween 80® (TW), which has shown potential as a penetration enhancer, on the mucosal retention of TBO for the PDT of oral cancer. 4% Chitosan-based mucoadhesive gels (CH gels) containing or not 5%TW were prepared (both containing 1%TBO), and their physicochemical properties (pH, rheology and mucoadhesion), TBO in vitro release profiles and TBO in vitro mucosal retention were evaluated. In vivo mucosal penetration studies of TBO followed by laser exposition were also carried out. The results showed that 4%CH gels containing 5%TW and 1%TBO have adequate mucoadhesive and rheological properties for oral mucosa use, although they present a slightly acid pH. TBO release studies showed that TW reduces TBO release, but it prolongs TBO release and increases TBO retention in the mucosa. In vivo studies showed that 4%CH gels containing 5%TW and 1%TBO cause an increase in the number of apoptotic cell, after laser exposition. In summary, 4%CH gels containing 5%TW may be a promising vehicle to optimize the penetration of TBO in oral mucosa and to improve the PDT response for the treatment of oral cancer.

Antimicrobial activity of photodynamic therapy in combination with colistin against a pan-drug resistant Acinetobacter baumannii isolated from burn patient.

Nosocomially-acquired multi-, extensively-, and pandrug resistant (MDR, XDR, and PDR) strains of microorganisms such as Acinetobacter baumannii remain a serious cause of infection and septic mortality in burn patients. Treatment of patients with nosocomial burn wound infections is often complicated by drug-resistant strains of A. baumannii. Today, many researchers are focusing on the investigation of novel non-antibiotic strategies such as photodynamic therapy (PDT). We report a new PDT strategy that suppresses colistin resistance in PDR A. baumannii by interfering with the expression of a pmrA/pmrB two-component system. In the current study, A. baumannii with a PDR feature isolated from a burn patient was used as a test strain. PDT was carried out using toluidine blue O (TBO) and light-emitting diode (LED) as a photosensitizer and radiation source, respectively. The antimicrobial susceptibility profiles were assessed for cells surviving PDT. The effects of sub-lethal PDT (sPDT) on the expression of the pmrA/pmrB two-component signal transduction system were evaluated by real-time quantitative reverse transcription PCR. Results of drug susceptibly testing (DST) in LED and TBO groups separately showed that the bacteria were resistant to all tested antibiotics, while the DST result of the LED+TBO group showed highly declining bacterial growth when compared with the control group. Reduction in the expression of pmrA and pmrB was observed in the treated strains after sPDT. This represents the first conclusive example of a direct role for the PDT in breaking antibiotic resistance by directly modulating two-component system activity.

Sae regulator factor impairs the response to photodynamic inactivation mediated by Toluidine blue in Staphylococcus aureus.

Photodynamic inactivation (PDI) involves the combined use of light and a photosensitizer, which, in the presence of oxygen, originates cytotoxic species capable of inactivating bacteria. Since the emergence of multi-resistant bacterial strains is becoming an increasing public health concern, PDI becomes an attractive choice. The aim of this work was to study the differential susceptibility to Toluidine blue (TB) mediated PDI (TB-PDI) of S. aureus mutants (RN6390 and Newman backgrounds) for different key regulators of virulence factors related to some extent to oxidative stress. Complete bacteria eradication of planktonic cultures of RN6390 S. aureus photosensitized with 13µM TB was obtained upon illumination with a low light dose of 4.2J/cm2 from a non-coherent light source. Similarly, complete cell death was achieved applying 1.3µM TB and 19J/cm2 light dose, showing that higher light doses can lead to equal cell death employing low photosensitizer concentrations. Interestingly, RN6390 in planktonic culture responded significantly better to TB-PDI than the Newman strain. We showed that deficiencies in rsbU, mgrA (transcription factors related to stress response) or agr (quorum sensing system involved in copper resistance to oxidative stress) did not modify the response of planktonic S. aureus to PDI. On the other hand, the two component system sae impaired the response to TB-PDI through a mechanism not related to the Eap adhesin. More severe conditions were needed to inactivate S. aureus biofilms (0.5mM TB, 157J/cm2 laser light). In mutant sae biofilms, strain dependant differential susceptibilities are not noticed.

Photodynamic therapy effect on cell growth inhibition induced by Radachlorin and toluidine blue O on Staphylococcus aureus and Escherichia coli: An in vitro study.

INTRODUCTION: Photodynamic therapy is an innovative treatment modality, which is appropriate for tumor detection and for the treatment of cancer as well as nontumoral diseases, such as psoriasis (2), bacterial and viral eradication. MATERIAL AND METHOD: Effect of two photosensitizer (toluidine blue O (TBO) and Radachlorin was investigated on Staphylococcus Aureus ATCC 25923 (American Type Culture Collection) and Escherichia coli (ATCC 25922). RESULTS: PDI by TBO caused S. aureus 5.83 log10 killing (P.Value<0.0001) and reduce 0.08 log 10 in E. coli (P.Value=0.321). PDI by Radachlorin(®) reduce 0.17 log 10 in E. coli (P.Value<0.0001) and S. aureus showed 6.1 log 10 colony count reduction. CONCLUSION: Within the limitation of this in vitro study, we can conclude that both PS have the same effect on S. aureus and E. coli with good inhibition effect on S. aureus and partial inhibition effect E. coli.

Modulation of virulence in Acinetobacter baumannii cells surviving photodynamic treatment with toluidine blue.

INTRODUCTION: Widespread resistance to antimicrobial agents has led to a dearth of therapeutic choices in treating Acinetobacter baumannii infections, leading to new strategies for treatment being needed. We evaluated the effects of photodynamic therapy (PDT) as an alternative antimicrobial modality on the virulence features of cell-surviving PDT. MATERIALS AND METHODS: To determine the sublethal PDT (sPDT), a colistin-resistant, extensively drug-resistant A. baumannii (CR-XDR-AB) clinical isolate and A. baumannii and ATCC 19606 strains, photosensitized with toluidine blue O (TBO), were irradiated with light emitting diodes, following bacterial viability measurements. The biofilm formation ability, outer membrane (OM) integrity, and antimicrobial susceptibility profiles were assessed for cell-surviving PDT. The effects of sPDT on the expression of virulent genes were evaluated by real-time quantitative reverse transcription PCR (qRT-PCR). RESULTS: sPDT resulted in the reduction of the biofilm formation capacity, and its metabolic activity in strains. The OM permeability and efflux pump inhibition of the sPDT-treated CR-XDR-AB cells were increased; however, there was no significant change in OM integrity in ATCC 19606 strain after sPDT. sPDT reduced the minimum inhibitory concentrations of the most tested antimicrobials by ≥2-fold in CR-XDR-AB. lpsB, blsA, and dnaK were upregulated after the strains were treated with sPDT; however, a reduction in the expression of csuE, epsA, and abaI was observed in the treated strains after sPDT. CONCLUSION: The susceptibility of CR-XDR-AB to a range of antibiotics was enhanced following sPDT. The virulence of strains is reduced in cells surviving PDT with TBO, and this may have potential implications of PDT for the treatment of A. baumannii infections.

Sub-lethal doses of photodynamic therapy affect biofilm formation ability and metabolic activity of Enterococcus faecalis.

BACKGROUND: During photodynamic therapy (PDT) in the treatment of a primary endodontic infection, it is extremely likely that microorganisms would be exposed to sub-lethal doses of PDT (sPDT). Although sPDT cannot kill microorganisms, it can considerably influence microbial virulence. This study was conducted to characterize the effect of sPDT using toluidine blue O (TBO), methylene blue (MB), and indocyanine green (ICG) on biofilm formation ability and metabolic activity of Enterococcus faecalis. METHODS: The antimetabolic and antibiofilm potential of ICG-, TBO-, and MB-sPDT against E. faecalis was analyzed at sub-lethal doses (1/2-1/64 minimum inhibitory concentration) using the XTT reduction assay, crystal violet assay, and scanning electron microscopy. RESULTS: Higher doses of sPDT adversely affected biofilm formation ability and metabolic activity. ICG-, TBO-, and MB-PDT at a maximum sub-lethal dose markedly reduced the formation of biofilm up to 42.8%, 22.6%, and 19.5%, respectively. ICG-, TBO-, and MB-sPDT showed a marked reduction in bacterial metabolic activity by 98%, 94%, and 82%, respectively. ICG-PDT showed a stronger inhibitory effect on biofilm formation in E. faecalis than MB- and TBO-PDT at sub-lethal levels. Interestingly, a gradual increase in metabolic activity and biofilm formation upon exposure to a lower dose of test sPDT were observed. CONCLUSION: sPDT showed dual effect on biofilm formation ability and metabolic activity of E. faecalis. High doses revealed antimetabolic and antibiofilm potential activity, whereas lower doses had conflicting results. Hence, when PDT is prescribed in clinical settings, the dose of PDT used in vivo should be taken into consideration.

In Vivo Feasibility of Electrostatic Precipitation as an Adjunct to Pressurized Intraperitoneal Aerosol Chemotherapy (ePIPAC).

BACKGROUND: Intraperitoneal chemotherapy is limited by tissue penetration. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) has been shown to improve drug uptake by utilizing the physical properties of gas and pressure. This study investigated the effect of adding electrostatic precipitation to further enhance the pharmacologic properties of this technique. METHODS: A comparative study was performed using an in vivo porcine model. There were 3 cases in each group, PIPAC and electrostatic precipitation pressurized intraperitoneal aerosol chemotherapy (ePIPAC), plus 1 negative control comparing intraperitoneal distribution and tissue uptake of 2 tracer substances (toluidine blue and DT01). Tracer uptake was determined by measuring DT01 in tissue and peritoneal fluid at the end of each procedure. RESULTS: Electrostatic precipitation of the aerosol was technically feasible in all ePIPAC animals. The aerosol was cleared completely from the visual field within 15 s in the ePIPAC group versus 30 min in the PIPAC group. The peritoneal surface was homogeneously stained in both groups. After 30 min, 1.5 % remaining DT01 was measured in samples of ePIPAC-treated peritoneal fluid versus 15 % in PIPAC animals (p = 0.01). Tissue concentration was increased after ePIPAC versus PIPAC (p = 0.06). CONCLUSIONS: ePIPAC is technically feasible and improves tissue uptake of 2 tracer substances compared to PIPAC by up to tenfold. Intraperitoneal distribution was homogeneous in both groups. ePIPAC has the potential to allow more efficient drug uptake, further dose reduction, a significant shortening of the time required for PIPAC application, and improved health and safety measures.

Using chitosan gels as a toluidine blue O delivery system for photodynamic therapy of buccal cancer: In vitro and in vivo studies.

BACKGROUND: Photodynamic therapy (PDT) is an emerging treatment that has demonstrated potential for the clinical treatment of buccal cancer. It is based on the photoactivation of a photosensitizer (PS) when irradiated by light at a specific wavelength. The light-excited PS generates reactive oxygen species that cause the destruction of tumor cells by apoptosis or necrosis. Toluidine Blue O (TBO) is a PS that has shown potential for PDT in cancer treatment. However, saliva and mechanical activities quickly remove the PS from the surface of the buccal mucosa. Therefore, the bioavailability of PS at the surface of target tissues is reduced. The aim of this study was to evaluate the potential of chitosan (CH) gels in TBO delivery to buccal tissue. METHODS: CH gels were obtained at different concentrations and their physico-chemical properties (pH and rheology), mucoadhesion, in vitro release profile, in vivo retention and in vivo efficacy by the ability to induce cell apoptosis were evaluated. RESULTS: CH-based mucoadhesive gels optimized the release and adherence of preparations at the target site. Specifically, 4% (w/w) CH gel showed adequate properties for buccal use, such as pH value, mucoadhesion, pseudoplastic behavior, extended release, minimal permeation and higher TBO retention by the mucosa. In vivo studies showed the potential of the gel to enhance TBO retention and induce cell apoptosis after laser irradiation. CONCLUSION: 4% (w/w) CH based mucoadhesive gel can be explored as a TBO delivery system in the PDT of oral cancer.

A clinical trial testing the efficacy of PDT in preventing amputation in diabetic patients.

The feet of diabetic patients continue to be an unsolved problem in medicine. Uncontrolled neuropathy, ulceration and infection usually lead to amputation and presently there is no effective and reliable method that can be used to provide an efficient cure. Overall improvement in the salvage strategies, based on comprehensive pre-clinical evaluation, debridement, antibiotic therapy and follow up, has shown improvements in certain hospital settings, but the general picture for patients with diabetic foot is to have some sort of amputation, especially in underserved populations. It is clearly necessary to develop novel treatment strategies for this worldwide health problem. Photodynamic therapy (PDT) is a treatment modality that uses light to generate in situ reactive oxygen species, which can cause cell death. PDT can be used to treat several diseases, including foot infections that do not respond well to antibiotic therapy. There are several characteristics of PDT that make it potentially ideal to treat diabetic feet: the photosensitizer is non-toxic in the dark, but after illumination it becomes a very efficient antimicrobial agent with topical use, and it can regenerate small bones, such as the phalanges. However, PDT is still not used in clinical practice to treat diabetic feet. Therefore, we decided to perform a clinical study to prove that PDT is an effective method to avoid amputation of infected diabetic feet. An inexpensive PDT protocol was developed and applied to 18 patients with osteomyelitis, classified as Grade 3 on the Wagner scale. Only one of these patients suffered amputation. At least two of them were cured from resistant bacteria strains without intravenous antibiotic therapy. In the control group of 16 patients, all of them ended up suffering amputation. The rate of amputation in the PDT group was 0.029 times the rate in the control group and the difference is clearly statistically significant (p=0.002).

Effect of the concentration of phenothiazine photosensitizers in antimicrobial photodynamic therapy on bone loss and the immune inflammatory response of induced periodontitis in rats.

BACKGROUND AND OBJECTIVE: Antimicrobial therapy can suppress periodontal pathogens and increase the effectiveness of conventional mechanical treatment. The aim of this study was to assess bone loss and the immune inflammatory response of rats under the influence of two photosensitizing agents (MB and TBO) at two different concentrations in antimicrobial photodynamic therapy (aPDT), used as an adjuvant therapy in the treatment of periodontitis. MATERIAL AND METHODS: Periodontitis was induced in the mandibular first molars of 162 rats. The animals were divided into nine groups: G1 - scaling and root planing (SRP); G2 - SRP plus 100 µg/mL of methylene blue (MB); G3 - SRP plus 10 mg/mL of MB; G4 - SRP plus 100 µg/mL of toluidine blue (TBO); G5 - SRP plus 10 mg/mL of TBO; G6 - SRP plus 100 µg/mL of MB and laser; G7 - SRP plus 10 mg/mL of MB and laser; G8 - SRP plus 100 µg/mL of TBO and laser; and G9 - SRP plus 10 mg/mL of TBO and laser. Six animals from each group were euthanized 7, 15, or 30 d after treatment. Bone loss (BL) in the furcation region was evaluated using histomorphometric and immunohistochemical analyses to detect the receptor activator of nuclear factor-Κappa B ligand (RANKL), osteoprotegerin (OPG) and tartrate-resistant acid phosphatase (TRAP). RESULTS: There was significantly less BL in animals treated with aPDT using low concentrations of MB and TBO at 7, 15 and 30 d. Immunohistochemical analysis revealed decreased RANKL and increased OPG in the aPDT groups and decreased TRAP-positive cells in G6 and G8. CONCLUSIONS: aPDT, using low concentrations of MB and TBO, was the most effective adjuvant therapy to SRP, acting indirectly as a downregulator of the molecular mechanisms that control bone resorption in periodontitis.

Effect of photoactivated disinfection with a light-emitting diode on bacterial species and biofilms associated with periodontitis and peri-implantitis.

BACKGROUND: To determine the effect of photoactivated disinfection (PAD) using toluidine blue and a light-emitting diode (LED) in the red spectrum (wave length at 625-635 nm) on species associated with periodontitis and peri-implantitis and bacteria within a periodontopathic biofilm. METHODS: Sixteen single microbial species including 2 Porphyromonas gingivalis and 2 Aggregatibacter actinomycetemcomitans and a multispecies mixture consisting of 12 species suspended in saline without and with 25% human serum were exposed to PAD. Moreover, single-species biofilms consisting of 2 P. gingivalis and 2 A. actinomycetemcomitans strains and a multi-species biofilm on 24-well-plates, grown on titanium discs and in artificial periodontal pockets were exposed to PAD with and without pretreatment with 0.25% hydrogen peroxide. Changes in the viability were determined by counting the colony forming units (cfu). RESULTS: PAD reduced the cfu counts in saline by 1.42 log10 after LED application for 30s and by 1.99 log10 after LED application for 60s compared with negative controls (each p<0.001). Serum did not inhibit the efficacy of PAD. PAD reduced statistically significantly (p<0.05) the cfu counts of the P. gingivalis biofilms. The viability of the A. actinomycetemcomitans biofilms and the multi-species biofilms was statistically significantly decreased when PAD was applied after a pretreatment with 0.25% hydrogen peroxide. The biofilm formed in artificial pockets was more sensitive to PAD with and without pretreatment with hydrogen peroxide compared with those formed on titanium discs. CONCLUSIONS: PAD using a LED was effective against periodontopathic bacterial species and reduced viability in biofilms but was not able to completely destroy complex biofilms. The use of PAD following pretreatment with hydrogen peroxide resulted in an additional increase in the antimicrobial activity which may represent a new alternative to treat periodontal and peri-implant infections thus warranting further testing in clinical studies.

[Progredient dyspnea and poor drainage in a peritoneal dialysis patient - case 2/2012]. / Zunehmende Dyspnoe und geringes Auslaufvolumen bei einem Peritonealdialysepatienten - Fall 2/2012.

HISTORY AND ADMISSION FINDINGS: We report on a peritoneal dialysis patients who presented with dyspnea, poor drainage and weight gain. INVESTIGATIONS: A chest x-ray showed a large pleural effusion on the right side. Thoracocentesis revealed a clear protein-devoid fluid with a glucose concentration greater than that of plasma. By intraperitoneal administration of toluidine blue, a pleuroperitoneal leakage was proven. DIAGNOSIS, TREATMENT AND COURSE: The patient underwent video-assisted thoracoscopy revealing a total of four spots of pleuroperitoneal leakage on the diaphragm after intraperitoneal administration of toluidine blue. Closure was attempted with the aid of a prolene patch which was stiched onto the diaphragm inducing adhesion to the lung. After three months bridging with hemodialysis, the peritoneal dialysis was commenced again without a recurrence of the leakage. CONCLUSIONS: Pleuroperitoneal leakage can occur during the course of peritoneal dialysis treatment leading to hydrothorax. Video-assisted thoracoscopy and patching of the diaphragm with a prolene mesh can be used to treat these patients.

Blue dye and red light, a dynamic combination for prophylaxis and treatment of cutaneous Candida albicans infections in mice.

The objective of this study was to investigate photodynamic therapy (PDT), using blue dye and red light, for prophylaxis and treatment of cutaneous Candida albicans infections in mice. A mouse model of skin abrasion infected with C. albicans was developed by inoculating wounds measuring 1.2 cm by 1.2 cm with 10(6) or 10(7) CFU. The use of a luciferase-expressing strain of C. albicans allowed real-time monitoring of the extent of infection in mice noninvasively through bioluminescence imaging. The phenothiazinium salts toluidine blue O (TBO), methylene blue (MB), and new methylene blue (NMB) were compared as photosensitizers (PS) for the photodynamic inactivation of C. albicans in vitro. PDT in vivo was initiated either at 30 min or at 24 h after fungal inoculation to investigate the efficacies of PDT for both prophylaxis and treatment of infections. Light at 635 ± 15 nm or 660 ± 15 nm was delivered with a light dose of 78 J/cm(2) (for PDT at 30 min postinfection) or 120 J/cm(2) (for PDT at 24 h postinfection) in multiple exposures with bioluminescence imaging taking place after each exposure of light. In vitro studies showed that NMB was superior to TBO and MB as the PS in the photodynamic inactivation of C. albicans. The efficacy of PDT was related to the ratio of PS concentration to fungal cell density. PDT in vivo initiated either at 30 min or at 24 h postinfection significantly reduced C. albicans burden in the infected mouse skin abrasion wounds. These data suggest that PDT is a viable approach for prophylaxis and treatment of cutaneous C. albicans infections.

Mast cells and angiogenesis in canine mammary tumor / Mastócitos e angiogênese nos tumores mamários caninos

The correlation between microvessel density and mast cells density in canine mammary tumors was studied. Sixty-five samples of canine mammary tumors, being 24 benign and 41 malignant, were analyzed. The routine Toluidine Blue staining method was used to assess the mast cells. To evaluate angiogenesis, the immunohistochemical expression of CD31 was assessed. There was no significant difference in either mast cells (P=0.44) or microvessel density (P=0.77) between malignant and benign tumors. A positive correlation was observed between microvessel density and mast cells (r=0.39; P=0.011) in malignant tumors. These results suggest that mast cells may play a role in canine mammary malignant tumors development, promoting angiogenesis, similar to some tumors described in the human species.

Estimou-se a correlação entre a densidade de microvasos e a densidade de mastócitos em tumores mamários caninos. Sessenta e cinco amostras de tumores mamários caninos - 24 benignos e 41 malignos - foram analisadas, pela técnica rotineira de coloração com Azul de Toluidina para avaliação da densidade de mastócitos. Para a avaliação da angiogênese, foi utilizada a técnica de imunoistoquímica para expressão de CD31. Não foram observadas diferenças significativas de mastócitos (P=0.44) ou densidade microvascular (P=0.77) entre tumores malignos e benignos. A correlação entre densidade microvascular e densidade de mastócitos foi positiva (r=0,39; P=0,011) em tumores malignos. Estes resultados sugerem que os mastócitos podem exercer um importante papel no desenvolvimento de tumores mamários malignos caninos mediante promoção da angiogênese, similarmente a alguns tumores descritos na espécie humana.

The adjunctive role of toluidine blue in detection of oral premalignant and malignant lesions.

PURPOSE OF REVIEW: To review the literature on toluidine blue (TBlue) and to discuss the utility of TBlue in assessing and in clinical management of patients with oral mucosal lesions. The literature search was conducted using key word search including oral cancer, oral premalignant lesions, and TBlue and by selecting references from the articles reviewed. RECENT FINDINGS: The findings of this review show that TBlue has utility as an adjunct in the detection of premalignant and malignant oral mucosal lesions and in identifying high-risk areas of lesions for biopsy in patients at increased risk of cancer when evaluated by experienced healthcare workers. SUMMARY: TBlue positive lesions, whether histologically benign or with dysplasia, predict molecular change and behavior of oral premalignant lesions. TBlue may provide information regarding lesion margins, accelerate the decision to biopsy, guide biopsy site selection and treatment of oral premalignant and malignant lesions. These findings support the utility of TBlue as a clinical adjunct in assessment of oral mucosal lesions.