Daniele Barreto Cunha Ferreira

Hybrid systems based on gold nanostructures and porphyrins as promising photosensitizers for photodynamic therapy

Gold nanostructures of two different shapes (spheres and rods) were synthesized to form a colloidal hybrid system with 5,10,15,20-tetrakis(N-methylpyridinium-4-yl)porphyrin tosylate salt (H2TM4PyP(OTs)4) (POR) for applications in photodynamic therapy (PDT) using light in the visible spectral range. Electron paramagnetic resonance (EPR) experiments in combination with spin trapping were used for the detection of reactive oxygen species (ROS) and evaluation of the efficiency of these novel hybrid systems as photosensitizers. It is shown that the hybrid system consisting of gold nanorods (AuNR) and porphyrin (POR) is by far more efficient than its isolated components. This enhanced efficiency is explained by a synergetic effect between the AuNR and the porphyrin, wherein a rapid energy transfer from the former to the latter produces a large amount of singlet oxygen followed by its conversion into hydroxyl radicals. The mechanism was investigated using different spin traps and different ROS inhibitors. On the other hand, spherical gold nanoparticles (AuNP) do not show this synergetic effect. The synergetic effect for gold nanorods/POR hybrid is attributed to a larger field enhancement close to the gold nanorod surface in addition to the electrostatic attraction between the components of the hybrid system.

Correlação entre perda auditiva e indicadores de risco em um serviço de referência em triagem auditiva neonatal

PURPOSE: To investigate the correlation between risk indicators and hearing impairment in infants of a Newborn hearing screening program METHODS: A retrospective study with 3151 newborn records with and without risk indicator for hearing loss, followed-up by a Newborn hearing screening program at a Public Hospital in the city of Belo Horizonte (MG). RESULTS: In the group without risk indicators, the incidence of hearing loss was 1.04%: 0.04% were sensorineural and 0.99% were conductive. In the group with risk indicators, the incidence of hearing loss was 8.38% (5.27% conductive and 3.1% sensorineural). In the high risk group one child (0.33%), who passed the screening, was diagnosed during the follow up with bilateral sensorineural mild hearing. The most common risk indicators were neonatal intensive care of >5 days (43.47%) followed by use of ototoxic drugs, (29.81%) and mechanical ventilation (28.88%). It was observed that children with suspected syndromes have 18 times more chance of acquiring sensorineural hearing loss. CONCLUSION: The risk indicator which correlated to hearing loss was suspicion of syndromes. Health promotion actions are necessary to reduce the presence of risk indicators found in the served population.

Efficient antibacterial nanosponges based on ZnO nanoparticles and doxycycline

Bacterial soft rot is responsible for the loss of about 25% of worldwide production in vegetables and fruits. Efforts have been made to develop an effective nanosponge with the capacity to load and release antibacterial drugs to protect plants. Based on the potential of the ZnO nanoparticles (ZnO-NPs) to achieve this goal, this study synthesized NP via the sol-gel and hydrothermal methods by controlling native defects, such as oxygen vacancies, using thermal treatments and reduced atmospheres. To characterize the ZnO NPs, X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), optical spectroscopy, electron paramagnetic resonance (EPR), Zeta Potential measurements and surface area with the Brunauer-Emmett-Teller (BET) method were used. The photophysical and photochemical properties via spin trapping method aligned with EPR using UVA light showed a greater formation of electron-hole pairs and hydroxyl radicals for the reduced ZnO NPs when compared with the oxidized ones. Additionally, we found that reduced ZnO-NPs have high effectively against Escherichia coli, Erwinia carotovora and Pantoea sp. bacteria using the photocatalytic effect in the UV range. Moreover, ZnO-NPs loaded with DOX release profile enables the release of DOX within 46days, where 25% was released during the first 10h followed by a second delivery phase with an interesting short-term efficacy (<1day) against E. carotovora and Pantoea sp. Bacteria. For the first time, it was demonstrated that ZnO-NPs and ZnO-NPs loaded with DOX have efficient UV photocatalytic activities against bacterial soft rot infections.

Power reflectance testing in newborns and infants

INTRODUCTION Auditory screening in newborns allows for detection of hearing problems early in life. However, middle ear diseases can make the diagnosis more difficult. OBJECTIVE To evaluate the power reflectance test as an indicator of the middle ear disease and to compare it to tympanometry. METHODS Case study evaluating 105 newborns and infants who participated in the audiology screening in 2013. The following exams were performed: transient otoacoustic emissions, power reflectance, and tympanometry. RESULTS In the optoacoustic emission evaluation, approximately 95% of the subjects passed the test. The specificity of power reflectance in all frequencies studied ranged from 75.3% to 95.9%, and that of tympanometry at 1000Hz ranged from 83% to 87.2%; there was agreement among these exams. CONCLUSION The outcome of power reflectance tests at 2000Hz and 3000Hz showed a correlation with tympanometry and otoacoustic emissions, and these were the most appropriate frequencies to determine middle ear disease through power reflectance measurement. It was also observed that values of power reflectance above reference levels suggested the presence of fluid in the middle ear, and thus a conductive hearing loss.

ANÁLISE DAS EMISSÕES OTOACÚSTICAS EVOCADAS POR PRODUTO DE DISTORÇÃO EM NEONATOS PREMATUROS

Purpose: toverifytheincidenceofchangesinotoacousticemissiondistortionproductinpremature� infantsandtoanalyzethemagnitudeofresponsesinrelationtothegestationalageinthispopulation.� Methods: observationalcross-sectionalstudy,�whichincludedresultsanalysisofdistortionproduct� otoacousticemissionsofpretermnewborns,�screenedinapublichospitalinBeloHorizonte,�from� August�2010�toFebruary,�2011.�Theinfantsweredividedintothreegroupsaccordingtothegestational� ages,�thefirstgroupconsistingofneonatesaging�28-30�weeks,�thesecondwasof�31-33�weeksand� thirdgroupof�34-36�weeks.�ThisstudywasapprovedbytheEthicsCommitteeofUFMGnumber� 0210.0.203.000-10. Results:�amongthe�44�childrenstudied�(93.62%)�distortionproductotoacoustic� emissions�(DPOAE)�werepresentandonlythreechildren�(6.38%)�hadabsentDPOAEs.�Regarding� theamplitudeanalysisoftheotoacousticemissionsandtheircomparisonsbetweengroups,� no� statisticallysignificantdifferencewasfoundbetweengestationalgroups,�howeverweobservedlower� pvaluesbetweengestationalgroupsathighfrequencies�-�6kHzand�5KHz.�Conclusion:�prematurity� initselfisnotafactorthatinfluencestheoutcomeofDPOAEinprematureneonates.

Maturação auditiva periférica: análise das amplitudes das emissões otoacústicas produto de distorção em neonatos pré-termo e a termo

Purpose : To compare preterm and term neonates in relation to the presence and amplitude of Distortion Product Otoacoustic Emissions (DPOAEs), as well as to characterize them regarding risk indicators for hearing loss. Methods : Study realized by the analysis of the DPOAEs (frequencies of 2000, 3000, 4000, 6000 and 8000 Hz) and risk indicators for hearing loss. The neonates were grouped according to the gestational age. The results were analyzed by ANOVA, Kruskal-Wallis and Chi-square tests (5%). Results : The sample consisted of 109 neonates (218 ears) in homogenous distribution related to gender and preterm/term classification. A high risk for hearing loss was observed in 40.4% of the infants. From the risk indicators for hearing loss, the most common were the duration of the stay in incubators and intensive care units (ICU) longer than five days. The DPOAEs were present in 209 ears (95.9%). The absence of responses to DPOEAs was significantly more frequent in groups with lower gestational age. It was observed an increase of the amplitudes of the DPOEAs with the increase of the gestational age, except for the frequency of 8000 Hz in the left ear. There were no differences between ears and genders regarding the presence and amplitude of the DPOAEs. Conclusion : There are differences between preterm and term groups in relation to the presence and amplitude of the DPOAEs: higher probability of failure in the groups with lower gestational age and (nonlinear) increase of the amplitudes with the increase of the gestational age. The findings suggest the phenomenon of maturation of the peripheral auditory system.