pHEMA hydrogels Passos, M. F.; Dias, D. R. C.; Bastos, G. N. T. ...
Journal of thermal analysis and calorimetry,
07/2016, Volume:
125, Issue:
1
Journal Article
Peer reviewed
Hydrogels of poly (2-hydroxyethyl methacrylate) (pHEMA) are suitable materials for medical applications. Synthesis, structural characterization, kinetic, physical properties and cell viability of ...these materials are reported in this article. The system was conducted via free radical polymerization in the absence of solvents or cross-linking agents. Hydrogels were obtained with excellent dimensional stability and high thermal stability (738 K), glass transition temperature of approximately 375 K and a degree of swelling of 66 ± 4 % in ethanol. The conversion of C=C double bond of the monomer 2-hydroxyethyl methacrylate was confirmed by Fourier transform infrared spectroscopy. Results showed dense and rough morphologies in the pHEMA, presence of high molecular interactions and good resistance to various organic solvents. In vitro tests showed excellent cell viability. The materials did not display cytotoxicity, and cells proliferated and adhered at a satisfactory rate on the hydrogel. These materials have great potential for biomedical application.
Graphical Abstract
pHEMA hydrogels are materials receiving great attention among researchers due to their ease of synthesis and biomedical application. This article demonstrates a new method of obtaining pHEMA hydrogels by bulk polymerization, in a single processing step and without the use of cross-linking agents. A kinetic study was evaluated, and the results of in vitro tests showed good cell proliferation.
Abstract Products derived from medicinal plants with antimicrobial activity are considered a promising alternative in the treatment of fungal infections. In this perspective, this study proposed to ...evaluate the antifungal activity of the dichloromethane fraction of Annona crassiflora Mart. against C. albicans strains. Tests were carried out to determine Minimum Inhibitory Concentration (MIC), Minimum Fungicide Concentration (MFC), microbial growth kinetics, fungal cell wall and membrane mechanisms of action, antifungal biofilm activity, and cytotoxic effects on human erythrocytes. The extract presented MIC and MFC values that ranged from 256 µg/mL to 1,024 µg/mL, with fungicidal activity in the microbial growth kinetics assay. The mechanism of action did not occur through damage to the cell wall or via binding to ergosterol in the membrane, though the fraction presents activity against biofilm and is not cytotoxic in human erythrocytes. The dichloromethane fraction of Annona crassiflora Mart. presented antifungal activity and reduced biofilm growth, without toxicity against human erythrocytes; however, further studies are needed to define its mechanism of action.
Resumo Produtos derivados de plantas medicinais com atividade antimicrobiana são considerados uma alternativa promissora no tratamento de infecções fúngicas. Nesta perspectiva, o estudo propôs avaliar a atividade antifúngica da fração diclorometano da Annona crassiflora Mart. frente às cepas de C. albicans. Realizou-se ensaios para determinação de Concentração Inibitória Mínima (CIM) e Concentração Fungicida Mínima (CFM), interferência sobre a cinética de crescimento microbiano, mecanismos de ação sobre a parede e a membrana celular fúngica, atividade antifúngica sobre o biofilme e os efeitos citotóxicos sobre eritrócitos humanos. Esse extrato apresentou valores da CIM e CFM que variaram de 256 µg/mL a 1,024µg/mL e no ensaio de cinética de crescimento microbiana, demonstrou atividade fungicida. O mecanismo de ação não ocorreu por danos na parece celular, tampouco por via ligação ao ergosterol da membrana. Demonstrou-se, ainda, que a fração tem ação frente ao biofilme e não é citotóxico em eritrócitos humanos. Assim, a fração diclorometano de Annona crassiflora Mart possui atividade antifúngica com capacidade de promover redução do crescimento do biofilme, não demosntrou toxicidade frente eritrócitos humanos, no entanto, necessita-se de mais estudos para definição do seu provável mecanismo de ação.
Abstract Introduction This study concerns a case series of 23 infants with a diagnosis of severe-to-profound hearing loss at 3 months old, who significantly improved (even reaching a normal auditory ...threshold) within their first year of life. Methods All infants were routinely followed up with audiological tests every 2 months after being fitted with hearing aids as necessary. A reliable consistency between the various test findings (DPOAE, ABR, behavioral responses, CAEP and ECoG) clearly emerged in most cases during the follow-up, albeit at different times after birth. Results The series of infants included 7 cases of severe prematurity, 6 of cerebral or complex syndromic malformations, 5 healthy infants, 2 with asymptomatic congenital CMV infection, and 1 case each of hyperbilirubinemia, hypoxia, and sepsis. All term-born infants showed a significant improvement over their initial hearing threshold by 6 months of age, while in most of those born prematurely the first signs of threshold amelioration occurred beyond 70 weeks of gestational age, and even beyond 85 weeks in one case. Conclusions Cochlear implantation (CI) should only be considered after a period of auditory stimulation and follow-up with electrophysiological and behavioral tests, and an accurate analysis of their correlation. In our opinion, CI can be performed after a period of 8 months in all term-born infants with persistent severe-to-profound hearing loss without risk of diagnostic error, whereas the follow-up for severely preterm infants should extend to at least 80 weeks of gestational age.
The objective of our study was to review retrospectively the clinical, radiological and therapeutic findings in 62 adults with acute mastoiditis treated at the ENT Department of Ferrara from 1992 to ...2010. 62 adult cases fulfilled the following inclusion criteria: otoscopical evidence of co-existent or recent otitis media; postauricular swelling, erythema or tenderness; protrusion of the auricle; fever and/or significant radiological findings of mastoiditis. Conservative treatment comprehended antibiotic ± ventilation tube. Surgical procedures comprehended mastoidectomy or mastoido-tympanoplasty. The incidence of adult’s mastoiditis in our district (0.99 cases/year/100.000 inhabitants) has maintained quite stable during the considered 19-year period. The typical clinical presentation was observed in 48 % of cases. Complications were meningitis (15 cases), meningo-encephalitis (1), meningitis associated with lateral sinus thrombosis (1), facial nerve paralysis (11), and labyrinthitis (8). In all cases except one, the facial palsy recovered completely and no mortality was observed due to these complications. Complete cure was obtained with conservative treatment in 69 % of uncomplicated cases and in 24 % of patients with intracranial complications. Mastoiditis in adults may present as the acute classical form, as well as latent forms which often have prolonged and insidious development followed by a rapid clinical deterioration. Clinical features are frequently atypical, while incidence of meningitis and other complications is still high particularly in the most elderly. Thus, great care is required from clinicians to make an early diagnosis in order to promote adequate treatment.
Malignant external otitis (MEO) is a rare infection of the temporal bone primarily affecting elderly patients and diabetics or immunocompromised individuals, which may have dismal prognosis if ...treatment is not prompt and adequate. Almost 95% of MEO cases reported in the literature are attributed to Pseudomonas aeruginosa, and this pathogen is isolated from aural drainage in > 90% of cases. However, in recent years fungal and polymicrobial temporal bone infections have been reported with increasing frequency. The aim of this paper is to discuss a possible pitfall in MEO treatment using an unusual clinical case. In this patient, bacteriological data positive for Pseudomonas delayed correct diagnosis of Aspergillus infection, which was obtained after surgical debridement and biopsy of the infra-temporal space.
To describe the effect of age and noise on high frequency hearing thresholds in an Italian population aged 70 years and older, in order to investigate the interaction between presbycusis and noise ...exposure.
We compared 460 subjects: 367 affected by presbycusis alone (204 women and 163 men) and 93 affected by presbycusis and noise exposure (eight women and 85 men). Pure tone average hearing thresholds, for each ear, were compared between groups, and between sexes and ages within groups.
A slight threshold difference was found between the two groups at 4 kHz. After adjusting for age and gender, this difference was found to be related only to differing patient age. Men's and women's thresholds differed significantly in both groups, especially at high frequencies, at which threshold deterioration was worse in men than women.
The threshold differences between patients with presbycusis with and without noise exposure were limited. Larger studies are needed to assess the relative effects of ageing and noise exposure on hearing thresholds.
The absorbable polyacid is one of the most used and studied materials in tissue engineering. This work synthesized a poly (L-lactic acid) (PLLA) through ring-opening polymerization and produced with ...it nanofibers by the electrospinning process. The PLLA was analyzed by FTIR and its cytotoxicity was evaluated by the MTT assay and Live/Dead® (Molecular Probes). The tests were performed in contact with human mesenchymal cells at varying times. The high rates of viability and proliferation of cells in contact with the PLLA shown by MTT and Live/Dead® tests demonstrate that this PLLA is a biocompatible material. There was also the successful production of electrospinning nanofibers, which can be converted for specific biomedical applications in the future.
Modena, founded by the Romans (183 BC), has always been conditioned by water in all its urban history. In the city, numerous archaeobotanical investigations have been carried out in order to ...reconstruct the natural landscape and human–environment interactions over time. During these investigations, four archaeological sites (two Roman and two medieval) have revealed deposits with a marked character of palaeobiocoenosis, largely resulting from the natural environment surrounding the sites, due to natural “seed rain”. These deposits are characterized by widespread evidence of plants related to water, constituting a valuable archive to investigate habitats which currently have become very rare and threatened, if they have not completely disappeared. The present paper aims to reveal the peculiarities of the Roman/medieval archaeocarpological floristic lists (through a comparison with the flora over the last two centuries in the area of Modena) and highlight the possible causes explaining the presence or the demise of several taxa , considering also the palaeoecological reconstruction of the environment in which they have been found.
To investigate the efficacy of photoactivated chromophore corneal collagen cross-linking (PACK)-CXL in the management of treatment-resistant infectious keratitis.
Observational cohort study.
...Forty-two eyes from 41 patients with treatment-resistant infectious keratitis.
Eyes underwent PACK-CXL treatment with the Dresden modified protocol in addition to standard antimicrobial therapy. The primary endpoint was the size of the corneal ulcer. Descriptive statistics, Wilcoxon rank test, McNemar test and Spearman correlation coefficient were used for statistical analysis, and
values lower than 0.05 were considered statistically significant.
Success rate at third postoperative month was of 90.5%. Statistical analyses showed a significant effect of (PACK)‑CXL with standard antimicrobial therapy to reduce corneal ulcer size (p=0.031).
As adjuvant therapy to standard antimicrobial treatment, PACK-CXL improves the outcomes in patients with treatment-resistant corneal ulcers.
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