Glutaraldehyde-crosslinking chitosan scaffolds reinforced with calcium phosphate spray-dried granules for bone tissue applications

The clinical demand for bone scaffolds as an alternative strategy for bone grafting has increased exponentially and, up to date, numerous formulations have been proposed to regenerate the bone tissue. However, most of these structures lack at least one of the fundamental/ideal properties of these materials (e.g., mechanical resistance, interconnected porosity, bioactivity, biodegradability, etc.). In this work, we developed innovative composite scaffolds, based on crosslinked chitosan with glutaraldehyde (GA), combined with different atomized calcium phosphates (CaP) granules - hydroxyapatite (HA) or biphasic mixtures of HA and β - tricalcium phosphate (β-TCP), with improved biomechanical behavior and enhanced biological response. This innovative combination was designed to improve the scaffolds' functionality, in which GA improved chitosan mechanical strength and stability, whereas CaP granules enhanced the scaffolds' bioactivity and osteoblastic response, further reinforcing the scaffolds' structure. The biological assessment of the composite scaffolds showed that the specimens with 0.2% crosslinking were the ones with the best biological performance. In addition, the inclusion of biphasic granules induced a trend for increase osteogenic activation, as compared to the addition of HA granules. In conclusion, scaffolds produced in the present work, both with HA granules or the biphasic ones, and with low concentrations of GA, have shown adequate properties and enhanced biological performance, being potential candidates for application in bone tissue engineering.publishe

Quercetin Liposomal Nanoformulation for Ischemia and Reperfusion Injury Treatment

PD/BD/135264/2017 UID/DTP/04138/2020 UIDP/04138/2020 UIDP/04378/2020 UIDB/04378/2020 LA/P/0140/2020 UIDB/50006/2020 UIDB/00100/2020Ischemia and reperfusion injury (IRI) is a common complication caused by inflammation and oxidative stress resulting from liver surgery. Current therapeutic strategies do not present the desirable efficacy, and severe side effects can occur. To overcome these drawbacks, new therapeutic alternatives are necessary. Drug delivery nanosystems have been explored due to their capacity to improve the therapeutic index of conventional drugs. Within nanocarriers, liposomes are one of the most successful, with several formulations currently in the market. As improved therapeutic outcomes have been demonstrated by using liposomes as drug carriers, this nanosystem was used to deliver quercetin, a flavonoid with anti-inflammatory and antioxidant properties, in hepatic IRI treatment. In the present work, a stable quercetin liposomal formulation was developed and characterized. Additionally, an in vitro model of ischemia and reperfusion was developed with a hypoxia chamber, where the anti-inflammatory potential of liposomal quercetin was evaluated, revealing the downregulation of pro-inflammatory markers. The anti-inflammatory effect of quercetin liposomes was also assessed in vivo in a rat model of hepatic IRI, in which a decrease in inflammation markers and enhanced recovery were observed. These results demonstrate that quercetin liposomes may provide a significant tool for addressing the current bottlenecks in hepatic IRI treatment.publishersversionpublishe

Nanostructure of cellulose microfibrils in spruce wood

The structure of cellulose microfibrils in wood is not known in detail, despite the abundance of cellulose in woody biomass and its importance for biology, energy, and engineering. The structure of the microfibrils of spruce wood cellulose was investigated using a range of spectroscopic methods coupled to small-angle neutron and wide-angle X-ray scattering. The scattering data were consistent with 24-chain microfibrils and favored a “rectangular” model with both hydrophobic and hydrophilic surfaces exposed. Disorder in chain packing and hydrogen bonding was shown to increase outwards from the microfibril center. The extent of disorder blurred the distinction between the I alpha and I beta allomorphs. Chains at the surface were distinct in conformation, with high levels of conformational disorder at C-6, less intramolecular hydrogen bonding and more outward-directed hydrogen bonding. Axial disorder could be explained in terms of twisting of the microfibrils, with implications for their biosynthesis

Prevalence of human papillomavirus in archival samples obtained from patients with cervical pre-malignant and malignant lesions from Northeast Brazil

<p>Abstract</p> <p>Background</p> <p>Human Papillomavirus (HPV) is considered as a necessary, but not sufficient, cause of cervical cancer. In this study, we aimed to assess the prevalence of HPV in a series of pre-malignant and malignant cervical lesion cases, to identify the virus genotypes, and to assess their distribution pattern according to lesion type, age range, and other considered variables. The samples were submitted to histopathological revision examination and analysed by polymerase chain reaction (PCR) for the presence of HPV DNA, followed by HPV typing by dot blot hybridisation.</p> <p>Findings</p> <p>Of the analysed samples, 53.7% showed pre-malignant cervical lesions, and 46.3% presented with cervical cancer. Most cancer samples (84.1%) were classified as invasive carcinoma. The mean age of these cancer patients was 47.3 years. The overall HPV prevalence was 82.4% in patients with pre-malignant lesions and 92.0% in the cancer patients. HPV 16 was the most prevalent type, followed by HPV 18 and 58, including both single and double infections. Double infection was detected in 11.6% of the samples, and the most common combination was HPV 16+18.</p> <p>Conclusions</p> <p>Cervical cancer appears to occur in women in a lower age range in the studied area, compared to the situation in other Brazilian regions. Furthermore, among the patients with CIN 3 and those with cancer, we observed a higher proportion of married women, women with more than one sexual partner, smokers, and individuals with less than an elementary education, relative to their counterparts.</p> <p>Findings</p> <p>The overall HPV prevalence was 82.4% in patients with pre-malignant lesions and 92.0% in the cervical cancer patients from Northeast Brazil. HPV 16 was the most prevalent type, followed by HPV 18 and 58. The most common double infection was HPV 16+18. Cervical cancer appears to occur in women in a lower age range in the Northeast Brazil. Among the patients with CIN 3 and those with cancer, we observed a higher proportion of married women, women with more than one sexual partner, smokers, and individuals with less than an elementary education, relative to their counterparts.</p

Geometric deep learning as a potential tool for antimicrobial peptide prediction

Antimicrobial peptides (AMPs) are components of natural immunity against invading pathogens. They are polymers that fold into a variety of three-dimensional structures, enabling their function, with an underlying sequence that is best represented in a non-flat space. The structural data of AMPs exhibits non-Euclidean characteristics, which means that certain properties, e.g., differential manifolds, common system of coordinates, vector space structure, or translation-equivariance, along with basic operations like convolution, in non-Euclidean space are not distinctly established. Geometric deep learning (GDL) refers to a category of machine learning methods that utilize deep neural models to process and analyze data in non-Euclidean settings, such as graphs and manifolds. This emerging field seeks to expand the use of structured models to these domains. This review provides a detailed summary of the latest developments in designing and predicting AMPs utilizing GDL techniques and also discusses both current research gaps and future directions in the field

Maior sobrevida em pacientes com marcadores imunogenéticos de rápida progressão para a AIDS: subsídios para a assistência de enfermagem

This study sought subsidies for improving nursing care programs for AIDS patients and aimed to verify the influence of changes in sexual behavior, including the adoption of safe sex practices, associated with the survival of AIDS patients with immunogenetic markers of rapid disease progression. 27 AIDS patients were interviewed, with genetic predisposition to rapid progression to AIDS. Genes were typified through the polymerase chain reaction. In spite of the presence of immunogenetic factors, associated with individual predisposition to a rapid evolution of the disease, changes in sexual behavior, including safe sex practices and antiretroviral therapy, may be related to greater survival. This suggests that counseling, detection of risk attitudes and health education, focusing on positive health behavior, are tools nursing must use with HIV-positive patients, with a view to better quality of life and greater survival among these individuals, even among those with genetic predisposition to rapid disease progression.Los autores buscan apoyo para el perfeccionamiento de programas de enfermería, orientados a pacientes con SIDA. La finalidad de este estudio fue la de verificar la influencia del comportamiento sexual en la supervivencia de pacientes con SIDA, portadores de genes asociados a la rápida progresión de la enfermedad. Fueron estudiados 27 pacientes con SIDA. Las tipificaciones de genes fueron realizadas por la reacción en cadena de la polimerasa. No obstante la presencia de factores inmunogenéticos, asociados a la predisposición individual a la rápida evolución de la enfermedad, cambios en el comportamiento sexual, con prácticas sexuales seguras y el uso de terapia antiretroviral, pueden estar relacionados con mayor supervivencia. La orientación, la detección de actitudes de riesgo y la educación de salud con enfoque en el comportamiento positivo de salud son herramientas que la enfermería debe utilizar con portadores del VIH, buscando la mejor calidad de vida y mayor supervivencia de esos individuos, incluso en aquellos que tienen predisposición genética a la rápida progresión de la enfermedad.Com enfoque em subsídios para o aperfeiçoamento de programas de enfermagem, direcionados a pacientes com aids, o presente estudo foi realizado com o objetivo de verificar a influência do comportamento sexual na sobrevida de pacientes com aids, portadores de genes associados à rápida progressão da doença. Foram entrevistados 27 pacientes com aids, geneticamente predispostos à rápida progressão da doença. As tipificações dos genes foram realizadas pela reação em cadeia da polimerase. Os resultados sugerem que, apesar da presença de fatores imunogenéticos, associados à predisposição individual para rápida evolução da doença, as mudanças do comportamento sexual, com adoção de práticas de sexo seguro, junto ao uso da terapia anti-retroviral, podem estar relacionadas com maior sobrevida. O aconselhamento, a detecção de atitudes de risco e a educação para saúde, enfocando o comportamento positivo de saúde, são ferramentas que a enfermagem deve utilizar a portadores do HIV, visando à melhor qualidade de vida e maior sobrevida desses indivíduos, mesmo naqueles geneticamente predispostos à rápida progressão da doença