Search

J-domain proteins (JDPs) are the largest family of chaperones in most organisms, but much of how they function within the network of other chaperones and protein quality control machineries is still an enigma. Here, we report on the latest findings related to JDP functions presented at a dedicated JDP workshop in Gdansk, Poland. The report does not include all (details) of what was shared and discussed at the meeting, because some of these original data have not yet been accepted for publication elsewhere or represented still preliminary observations at the time.

Abstract Human wellbeing depends on ecosystem services, highlighting the need for improving the ecosystem-service multifunctionality of food and feed production systems. We study Swiss agricultural grasslands to assess how employing and combining three widespread aspects of grassland management and their interactions can enhance 22 plot-level ecosystem service indicators, as well as ecosystem-service multifunctionality. The three management aspects we assess are i) organic production system, ii) an eco-scheme prescribing extensive management (without fertilization), and iii) harvest type (pasture vs. meadow). While organic production system and interactions between the three management aspects play a minor role, the main effects of eco-scheme and harvest type considerably shape single services. Moreover, the eco-scheme ‘extensive management’ and the harvest type ‘pasture’ enhance plot-scale ecosystem-service multifunctionality, mostly through facilitating cultural services at the expense of provisioning services. These changes in ecosystem-service supply occur mainly via changes in land-use intensity, i.e., reduced fertilizer input and harvest frequency. In conclusion, diversifying grassland management where this is currently homogeneous across farms and landscapes depicts an important first step to improve landscape-scale multifunctionality for sustainable grassland systems. To meet societal ecosystem services demand, the three studied management aspects can be systematically combined to increase ecosystem services that are in short supply.

A prevenção do suicídio é uma questão de saúde pública que requer atenção e comprometimento da sociedade. Abrange diversas ações, sendo que profissionais da saúde, educação e mídias sociais são fundamentais nessas tarefas. Desenvolvemos um projeto de extensão para realizar atividades educativas com esse público, visando refletir e sensibilizar sobre diferentes perspectivas do suicídio. Ao longo de quatro encontros com cada grupo profissional, foram realizadas rodas de conversa e vivências grupais. Para isso, usamos recursos didáticos, dinâmicas e textos literários para tratar sobre os fatores de risco e proteção, considerando as especificidades da realidade local, a importância da abordagem do tema nas escolas e a regulação da veiculação de notícias sobre comportamentos suicidas. Além disso, o projeto encerrou com um colóquio que reuniu 252 pessoas e discutiu a prevenção do suicídio como um caminho interdisciplinar de cuidado. Portanto, essa experiência proporcionou espaços de escuta, diálogo e reflexão sobre a problemática do suicídio, além de reconhecer a importância da abordagem interdisciplinar para a prevenção desse fenômeno.

The larvae of the black soldier fly (BSFL, Hermetia illucens) efficiently close resource cycles. Next to the nutrient-rich insect biomass used as animal feed, the residues from the process are promising plant fertilizers. Besides a high nutrient content, the residues contain a diverse microbial community and application to soil can potentially promote soil fertility and agricultural production through the introduction of beneficial microbes. This research assessed the application of the residues on plant-associated bacterial and fungal communities in the rhizosphere of a grass-clover mix in a 42-day greenhouse pot study. Potted soil was amended with BSFL residues (BR+) or conventional compost (CC+) produced by Rwandan waste management companies in parallel to residues and compost sterilized (BR-, CC-) by high-energy electron beam (HEEB) as abiotic controls. The fertilizers were applied at a rate of 150 kg N ha−1. Soil bacterial and fungal communities in both fertilizer and soil were assessed by high-throughput sequencing of ribosomal markers at different times after fertilizer application. Additionally, indicators for soil fertility such as basal respiration, plant yield and soil physicochemical properties were analyzed. Results showed that the application of BSFL residues influenced the soil microbial communities, and especially fungi, stronger than CC fertilizers. These effects on the microbial community structure could partly be attributed to a potential introduction of microbes to the soil by BSFL residues (e.g., members of genus Bacillus) since untreated and sterilized BSFL residues promoted different microbial communities. With respect to the abiotic effects, we emphasize a potential driving role of particular classes of organic matter like fiber and chitin. Indeed, especially taxa associated with decomposition of organic matter (e.g., members of the fungal genus Mortierella) were promoted by the application of BSFL residues. Soil fertility with respect to plant yield (+17% increase compared to unamended control) and basal respiration (+16% increase compared to unamended control) tended to be improved with the addition of BSFL residues. Findings underline the versatile opportunities for soil fertility arising from the application of BSFL residues in plant production and point to further research on quantification of the described effects.

The human gut microbiota, a complex community of microorganisms living in the digestive tract, consists of more than 1500 species distributed in more than 50 different phyla, with 99% of bacteria coming from about 30–40 species. The colon alone, which contains the largest population of the diverse human microbiota, can harbor up to 100 trillion bacteria. The gut microbiota is essential in maintaining normal gut physiology and health. Therefore, its disruption in humans is often associated with various pathological conditions. Different factors can influence the composition and function of the gut microbiota, including host genetics, age, antibiotic treatments, environment, and diet. The diet has a marked effect, impacting the gut microbiota composition, beneficially or detrimentally, by altering some bacterial species and adjusting the metabolites produced in the gut environment. With the widespread use of non-nutritive sweeteners (NNS) in the diet, recent investigations have focused on their effect on the gut microbiota as a mediator of the potential impact generated by gastrointestinal-related disturbances, such as insulin resistance, obesity, and inflammation. We summarized the results from pre-clinical and clinical studies published over the last ten years that examined the single effects of the most consumed NNS: aspartame, acesulfame-K, sucralose, and saccharin. Pre-clinical studies have given conflicting results for various reasons, including the administration method and the differences in metabolism of the same NNS among the different animal species. A dysbiotic effect of NNS was observed in some human trials, but many other randomized controlled trials reported a lack of significant impacts on gut microbiota composition. These studies differed in the number of subjects involved, their dietary habits, and their lifestyle; all factors related to the baseline composition of gut microbiota and their response to NNS. The scientific community still has no unanimous consensus on the appropriate outcomes and biomarkers that can accurately define the effects of NNS on the gut microbiota.

Soil compaction caused by highly mechanized agriculture can constrain soil microbial diversity and functioning. Physical pressure on the soil decreases macropores and thereby limits oxygen diffusion. The associated shift from aerobic to anaerobic conditions can reduce nitrification and promote denitrification processes, leading to nitrogen (N) losses and N depletion that affect plant productivity. High soil moisture content during trafficking can exacerbate the negative effects of soil compaction. However, the extent to which soil moisture amplifies the effects of compaction on the soil microbiome and its control over N cycling is not well understood. Using a controlled greenhouse experiment with two different crops (pea and wheat), we compared the effects of compaction at three different soil moisture levels on soil physicochemical properties, microbial diversity, and the abundance of specific N species and quantification of associated microbial functional groups in the N cycle. Soil compaction increased bulk density from 15% (light compaction) to 25% (severe compaction). Compaction delayed germination in both crops and reduced yield by up to 60% for pea and 40% for wheat. Compaction further induced crop-specific shifts in microbial community structures. After compaction, the relative abundance of denitrifiers increased along with increased nitrate (NO3–) consumption and elevated nitrous oxide (N2O) concentrations in the soil pores. Conversely, the relative abundance of nitrifiers remained stable under compaction, but potentially decelerated nitrification rates, resulting in ammonium (NH4+) accumulation in the soil. This study showed that soil compaction effects are proportional to the initial soil moisture content, which could serve as a good indicator of compaction severity on agricultural fields. However, the impact of soil compaction on crop performance and on microbial communities and functions associated with the N cycle were not necessarily aligned. These findings demonstrate that not only the soil physical properties but also various biological indicators need to be considered in order to provide more precise recommendations for developing sustainable farming systems.

The ribosome-associated complex (RAC), which contains the Hsp40 protein Zuo1 and the non-canonical Hsp70 protein Ssz1 forms a chaperone triad with the fungal-specific Hsp70 protein Ssb. Here the authors combine X-ray crystallography, crosslinking and biochemical experiments and present the structure of the Zuo1 N-terminus bound to Ssz1 and demonstrate that Ssz1 is an active chaperone for nascent chains.

ABSTRACT Objective: To understand the role of nurses in field hospitals aimed at patients with Covid-19. Methods: Qualitative research based on Alfred Schütz’s social phenomenology. Twenty nurses working in São Paulo were interviewed between May and June 2020. The testimonies were organized and analyzed based on the theoretical-methodological and thematic framework. Results: The following categories emerged: “Nurses’ challenges in field hospital care”, “Visibility of nursing in the Covid-19 pandemic scenario” and “Covid-19 post-pandemic professional valorization”. Final considerations: The reflection on the results that emerged in this study may contribute to support improvements in training, working conditions and valuing nurses, considering the importance of this professional category in the scope of health services. New investigations may increase knowledge in the area, providing subsidies for professional role in this and other health situations that require nursing intensity and excellence.

ABSTRACT Objective: To understand the experiences of intensive care unit nurses who provide care to patients with COVID-19. Methods: Qualitative study grounded in Alfred Schütz’s social phenomenology in which 20 nurses who work in intensive care units at public and private hospitals were interviewed between July and September 2020. Data were analyzed according to the adopted theoretical-methodological framework and the literature related to the subject. Results: The interviewed nurses mentioned demands about working conditions, professional recognition and training, and support to physical and mental health, which proved necessary considering the care intensity experienced by these professionals during the COVID-19 pandemic. Conclusion: Learning the nurses’ experiences evidenced the need to adjust to a new way of providing care that included the physical space, new institutional protocols, continuous use of protective equipment, and patients’ demand for special care. This originated the necessity to be around situations that interfered with their health and motivated them to carry out professional projects after the COVID-19 pandemic.

The SUMOylation machinery is a regulator of neuronal activity and synaptic plasticity. It is composed of SUMO isoforms and specialized enzymes named E1, E2 and E3 SUMO ligases. Recent studies have highlighted how SUMO isoforms and E2 enzymes localize with synaptic markers to support previous functional studies but less information is available on E3 ligases. PIAS proteins - belonging to the protein inhibitor of activated STAT (PIAS) SUMO E3-ligase family - are the best-characterized SUMO E3-ligases and have been linked to the formation of spatial memory in rodents. Whether however they exert their function co-localizing with synaptic markers is still unclear. In this study, we applied for the first time structured illumination microscopy (SIM) to PIAS ligases to investigate the co-localization of PIAS1 and PIAS3 with synaptic markers in hippocampal and cortical murine neurons. The results indicate partial co-localization of PIAS1 and PIAS3 with synaptic markers in hippocampal neurons and much rarer occurrence in cortical neurons. This is in line with previous super-resolution reports describing the co-localization with synaptic markers of other components of the SUMOylation machinery.

El artículo presenta la aplicación de tres metodologías que buscan mejorar la percepción del peligro de conductores inexpertos en carreteras de montaña, mediante retroalimentación basada en fotografías, videos cortos y simulación de recorridos reales. Los escenarios de las tres metodologías se evaluaron con la metodología iRAP y estos resultados se compararon con la percepción del peligro percibida por los conductores inexpertos. La metodología iRAP califica las carreteras de 1 a 5 estrellas, donde 1 es la más peligrosa y 5 es la más segura. A tres grupos en formación se les aplicó una evaluación inicial, luego un proceso de formación mediante retroalimentación y, finalmente, una evaluación final. La aplicación de fotografías mejoró la percepción del peligro en carreteras más seguras (3 a 4 estrellas). Mediante videos, las mujeres reaccionaron mejor a la formación en percepción del peligro en carreteras más peligrosas (1 a 2 estrellas). Al aplicar simulación de recorridos reales, no hubo mejoras en la percepción del peligro. Se concluye que la aplicación de fotografías y videos son válidos, pero es preciso reforzar la formación de los conductores inexpertos para identificar elementos instigadores de riesgo en carreteras de montaña.

Objective: to understand the path taken in the public health system by people with morbid obesity in the search for bariatric surgery. Method: qualitative research based on the social phenomenology of Alfred Schütz, with 17 hospitalized morbidly obese people, with a scheduled date for bariatric surgery. The phenomenological interview with open questions was used and the statements were analyzed in the light of the theoretical-methodological framework and literature related to the theme. Results: the participants were able to schedule bariatric surgery by referring friends, family and public people. The waiting list for the procedure generated anguish and anxiety due to fear of surgery, weight gain, risk of worsening health and physical limitations, but it helped prepare for its performance. The experience lived in the search for bariatric surgery led these people to want continuity of care in the Basic Health Unit, after the surgery, by professionals trained to meet their needs. Conclusion: the aspects inscribed in the path of people in search of bariatric surgery signal the need to strengthen the assistance-related flows of the public health system and to invest in professional training to reduce the social inequalities in access to bariatric surgery and increased quality of services.

Abstract Objective: To understand the health care experience of individuals with morbid obesity assisted in public healthcare services. Method: This was a qualitative study based on Alfred Schütz’s social phenomenology, carried out in the medical-surgical clinic of a public hospital in São Paulo, Brazil. Interviews with open questions were conducted between January and April 2017. Results: Seventeen individuals with morbid obesity participated in the study. The findings revealed care(lessness) experiences of obese individuals in the Brazilian Healthcare System in terms of structure/logistics and human resources. Study participants shared care expectations about health care management and staff, and further considered the Primary Health Care service as a scenario of power to have their obesity-related care needs met. Conclusion: The findings need to be carefully (re)examined by the healthcare system’s micro- and macro management, as well as by health teaching and research personnel, in order to integrate, follow up and qualify care actions towards the prevention and control of obesity in public healthcare services.

In yeast, the heterodimeric ribosome-associated complex (RAC) acts in concert with the Hsp70 protein Ssb, forming a unique chaperone triad. Here the authors use structural and biochemical approaches to shed light on how translation and folding are coupled in eukaryotes.

Abstract Background As the most incident tumor among women worldwide, breast cancer is a heterogeneous disease. Tremendous efforts have been made to understand how tumor characteristics as histological type, molecular subtype, and tumor microenvironment collectively influence disease diagnosis to treatment, which impact outcomes. Differences between populations and environmental and cultural factors have impacts on the origin and evolution of the disease, as well as the therapeutic challenges that arise due to these factors. We, then, compared copy number variations (CNVs) in mucinous and nonmucinous luminal breast tumors from a Brazilian cohort to investigate major CNV imbalances in mucinous tumors versus non‐mucinous luminal tumors, taking into account their clinical and pathological features. Methods 48 breast tumor samples and 48 matched control blood samples from Brazilian women were assessed for CNVs by chromosome microarray. Logistic regression and random forest models were used in order to assess CNVs in chromosomal regions from tumors. Results CNVs that were identified in chromosomes 1, 5, 8, 17, 19, and 21 classify tumors according to their histological type, ethnicity, disease stage, and familial history. Conclusion Copy number alterations described in this study provide a better understanding of the landscape of genomic aberrations in mucinous breast cancers that are associated with clinical features.

SUMOylation of proteins plays a key role in modulating neuronal function. For this reason, the balance between protein SUMOylation and deSUMOylation requires fine regulation to guarantee the homeostasis of neural tissue. While extensive research has been carried out on the localization and function of small ubiquitin-related modifier (SUMO) variants in neurons, less attention has been paid to the SUMO-specific isopeptidases that constitute the human SUMO-specific isopeptidase (SENP)/Ubiquitin-Specific Protease (ULP) cysteine protease family (SENP1-3 and SENP5-7). Here, for the first time, we studied the localization of SENP1, SENP6, and SENP7 in cultured hippocampal primary neurons at a super resolution detail level, with structured illumination microscopy (SIM). We found that the deSUMOylases partially colocalize with pre- and post-synaptic markers such as synaptophysin and drebrin. Thus, further confirming the presence with synaptic markers of the negative regulators of the SUMOylation machinery.

We quantified nitrous oxide (N2O) fluxes and total denitrification (N2O + N2) in an acidic (Ferralsol) and a near-neutral pH soil (Cambisol) to determine whether biochar’s alkalinization effect could be the mechanism inducing potential reductions in N2O fluxes. In Ferralsol, decreases in N2O emissions and in the N2O to N2O + N2 ratio were observed in both biochar and lime treatments. In Cambisol, neither biochar nor lime decreased N2O emissions, despite significantly increasing soil pH. The abundance and community structure of nosZ gene-bearing microorganisms indicated that gene abundances did not explain biochar effects, but a higher diversity of nosZ gene-bearing microorganisms correlated to lower total denitrification. Overall, our results suggest that biochar’s potential to decrease N2O emissions, through soil alkalinization, may be more effective in acidic soils.

ABSTRACT Objective Identify the knowledge produced on nursing interventions with people suffering from obesity in Primary Health Care. Method Integrative literature review of publications indexed in the databases: CINAHL, LILACS, MEDLINE, SciELO, SCOPUS and WEB OF SCIENCE, between 2011 and 2016. Results Thirty-three articles were selected. The knowledge produced covered two themes: “Counseling aimed at weight control and promotion of healthy lifestyle habits” and “Perception of Primary Health Care nurses regarding interventions with people with obesity.” Conclusion The results may help prompt reflections on professional training, management, and health services in terms of the relevance of nurses working with people suffering from obesity, with the support of digital technologies, motivational techniques, and nursing consultations. This could enhance their activities in the multiprofessional teams in which they participate at this healthcare level.

The objective of this study was to identify the performance of Chilean primary health care nurses. This was a qualitative study based on the approach of social phenomenology. Data collection was conducted between January and April 2013 through interviews with 13 nurses. Nurse performance showed that they experience greater professional autonomy and are closer to users; however, they suffered from professional burnout. Their expectations included the desire to be recognized for their work and better service management. Contributions of this study include the possibility of considering new designs for professional management practices in primary health care from the perspective of Chilean nurses. These designs should be based on the reorganization of work processes and by occupying spaces in macropolitics, influencing the professional performance of nurses at this level of health care.

ECG derived respiration (EDR) is a technique applied to estimate the respiration signal using only the electrocardiogram (ECG). Different approaches have been proposed in the past on how respiration could be gained from the ECG. However, in many applications only one of them is used while the others are not considered at all. In this paper, we propose a new algorithm for the optimal linear combination of different EDR methods in order to create a more accurate estimation. Using two well known databases, it was statistically shown that an optimally chosen fixed set of coefficients for the linear combination delivers a better estimation than each of the methods used solely.

Este artículo explora el fenómeno de la negación no psicótica del embarazo, una situación en la cual la mujer desconoce que está embarazada por cinco meses o más, o hasta el parto. Este fenómeno es explorado a través de tres conceptos psicoanalíticos distintos: desautorización, embarazo impensable y experi encia de indiferencia. El mecanismo de defensa de desautorización en casos de negación del embarazo es considerado como una explicación por que la mujer no enlaza sus cambios corporales con un posible embarazo. Se percibe que mujeres que no enlazan el acto sexual con el embarazo que sufrieron por causa de una situación traumática. Estas situaciones son comprendidas en el concepto de embarazo impensable. En este artículo, experiencia de indiferencia es relacionada con pacientes fronterizos, una estructura ps icopatológica posible para mujeres que no saben que están embarazadas.

OBJECTIVE: The physicochemical properties of hydroxyapatite (HA) granules were observed to affect the biological behavior of graft materials. The aim of this work was to analyze the tissue response of two HA granules with different crystallinity and Ca/P ratio in vivo. MATERIAL AND METHODS: The HA granules were produced in the Biomaterials Laboratory (COPPE/UFRJ). The testing materials were HA granules presenting a Ca/P molar ratio of 1.60 and 28% crystallinity (HA-1), and a Ca/P molar ratio of 1.67 and 70% crystallinity (HA-2). Both HAs were implanted into a critical-size calvaria rat defects. RESULTS: To note, in the control group, the bone defects were filled with blood clot only. Descriptive and histomorphometric analyses after 1, 3, and 6 months postoperatively showed mild inflammatory infiltrate, mainly comprising macrophage-like and multinucleated giant cells, and an increase in the volume density of the fibrous tissues (p

As observações do cotidiano na Unidade de Terapia Intensiva Neonatal (UTIn), as reflexões sobre a dicotomia entre a teoria, o discurso e o modo de atuação de muitos enfermeiros junto aos pais dos recém-nascidos, suscitaram-nos inquietações que nos levaram a desenvolver este estudo, com os objetivos de conhecer a vivência da enfermeira no cuidado ao recém-nascido e aos seus pais na UTIn e compreender como as enfermeiras vivenciam o processo de vínculo afetivo entre recém-nascidos internados em UTIn e seus pais. Realizamos a pesquisa de acordo com a abordagem da fenomenologia social de Alfred Schütz. Os sujeitos do estudo foram oito enfermeiras assistenciais, com experiências em UTIn de hospitais públicos e privados. Dentre as categorias concretas do vivido, que emergiram dos discursos, destacamos o Contato Humano. Os resultados da análise mostraram que as enfermeiras percebem-se como elo de aproximação entre filhos e pais e acreditam que exercem papel importante na formação de vínculo afetivo entre eles.Las observaciones de lo cotidiano en la Unidad de Terapia Intensiva Neonatal (UTIn), las reflexiones sobre la dicotomía entre la teoría, el discurso y el modo de actuación de muchos enfermeros junto a los padres de los recién nacidos, nos suscitaron inquietudes que nos llevaron a desarrollar este estudio, con los objetivos de conocer la vivencia de la enfermera en el cuidado al recién nascido y a sus padres en la UTIn y comprender como las enfermeras experimentan el proceso de vínculo afectivo entre recién nascidos internados en UTIn y sus padres. Realizamos la investigación de acuerdo con el abordaje de la fenomenología social de Alfred Schütz. Los sujetos del estudio fueron ocho enfermeras asistenciales, con experiencias en UTIn de hospitales públicos y privados. Entre las categorías concretas de lo vivido, que emergieron de los discursos, destacamos el Contacto Humano. Los resultados del análisis mostraron que las enfermeras se perciben como un elemento de aproximación entre hijos y padres y creen que ejercen un papel importante en la formación de un vínculo afectivo entre ellos.The study was motivated by observations of the routine at neonatal intensive care units (NICU), thoughts about the dichotomy between theory, discourse, and the practice of many nurses towards the newborns' parents. The objectives were to learn about nurses' experiences regarding neonatal care to newborns and their parents, and to understand how nurses experience the process of affective attachment between newborns hospitalized at NICUs and their parents. This study was developed according to the social phenomenology approach of Alfred Schütz. Study subjects were eight practical nurses who had worked at NICU of public and private hospitals. Categories of experience emerged from the discourses, including Human Contact. The analysis revealed that nurses see themselves as the connection between parents and children, and believe they play an important role in creating the affective attachment between parent and child.

The objective of the present study was to evaluate the quality and intensity of the tissue response to two synthetic hydroxyapatites implanted in critical defects in the skulls of rats. Sixty animals were divided into three experimental groups: I (control), II (HA-1 = HA with 28% crystallinity) and III (HA-2 = HA with 70% crystallinity). They were sacrificed 1, 3, 6, and 9 months after implantation (n = 5 individuals per group/period). Histomorphometric analysis included i) counting of polymorphonuclear leucocytes, mast cells, macrophages and foreign body multinucleated giant cells stained with anti-lysozyme; ii) microvascular density stained with anti-Factor VIII and iii) degree of cell proliferation stained with anti-PCNA. There were no significant differences between the experimental groups in either the quality or quantity of cells in the inflammatory infiltrate, or the degree of angiogenesis and cell proliferation. We conclude that HA-1 and HA-2 are biocompatible and that the physico-chemical differences of these biomaterials did not affect cellular response.

A stability study of azithromycin in ophthalmic preparations was developed by submission to different types of light, temperature and pH, using the biodiffusion assay (cylinder 3 x 3) for the quantifications. Bacillus subtilis, ATCC 9372, was used as test organism. The used concentration range was of 50 to 200 µg/mL. The study demonstrated that the drug suffered degradation when submitted to the ultraviolet light, germicide light, solar luminosity, acid solution, basic solution and hydrogen peroxide solution. The results were analyzed by the analysis of variance (ANOVA).O estudo de estabilidade de azitromicina em preparações oftálmicas foi realizado após exposição a diferentes tipos de luz, temperatura e pH, utilizando o método de difusão em ágar (cilindros 3 x 3) para as quantificações. A faixa de concentração foi de 50 a 200 µg/mL. O estudo demonstrou que o fármaco sofreu degradação quando submetido às luzes ultravioleta, germicida e solar, e a soluções ácida, alcalina e de peróxido de hidrogênio. Os resultados foram analisados através da análise da variância (ANOVA).

Calcium phosphate salts, or more specifically hydroxyapatite, are products of great interest in the fields of medical and dental science due to their biocompatibility and osteoconduction property. Deproteinized xenografts are primarily constituted of natural apatites, sintered or not. Variations in the industrial process may affect physicochemical properties and, therefore, the biological outcome. The purpose of this work was to characterize the physical and chemical properties of deproteinized xenogenic biomaterials, Bio-Oss (Geistlich Biomaterials, Wolhuser, Switzerland) and Gen-Ox (Baumer S.A., Brazil), widely used as bone grafts. Scanning electron microscopy, infrared region spectroscopy, X-ray diffraction, thermogravimetry and degradation analysis were conducted. The results show that both materials presented porous granules, composed of crystalline hydroxyapatite without apparent presence of other phases. Bio-Oss presented greater dissolution in Tris-HCl than Gen-Ox in the degradation test, possibly due to the low crystallinity and the presence of organic residues. In conclusion, both commercial materials are hydroxyapatite compounds, Bio-Oss being less crystalline than Gen-Ox and, therefore, more prone to degradation.

The aim of this work was to characterize six hydroxyapatites in granular form for applications in medicine and dentistry as bone graft and to compare with manufacturers' specification. These samples were produced by four different manufacturers, and all of them are easily available in the Brazilian market. Physicochemical characterization was carried out by using electron microscopy (SEM), X-ray diffraction (XRD), infrared spectroscopy (FTIR) and surface area (BET) measurements. The results show that just one hydroxyapatite sample exhibited characterisitics in perfect agreement with the manufacturers' specifications. The studied parameters, namely crystallinity, surface area and composition may be used to estimate hydroxyapatite's biodegradability and as a criterion for quality control.O objetivo desse trabalho foi caracterizar seis hidroxiapatitas granulares para aplicação em área médico-odontológica como material de enxerto. Estes materiais foram produzidos por quatro diferentes fabricantes e são todos facilmente disponíveis no mercado brasileiro. A caracterização físico-química foi realizada por meio de microscopia eletrônica de varredura, difração de raios-X, espectroscopia de infravermelho e área superficial específica (BET). Os resultados mostraram que apenas um dos produtos teve a caracterização perfeitamente de acordo com a especificação do fabricante. Os parâmetros de cristalinidade, área superficial e composição podem ser usados para estimar a biodegradabilidade da hidroxiapatita e como critério de controle de qualidade desses materiais.

Abstract non disponibile

Abstract non disponibile