Tracking Bacterial Nanocellulose in Animal Tissues by Fluorescence Microscopy.

The potential of nanomaterials in food technology is nowadays well-established. However, their commercial use requires a careful risk assessment, in particular concerning the fate of nanomaterials in the human body. Bacterial nanocellulose (BNC), a nanofibrillar polysaccharide, has been used as a food product for many years in Asia. However, given its nano-character, several toxicological studies must be performed, according to the European Food Safety Agency's guidance. Those should especially answer the question of whether nanoparticulate cellulose is absorbed in the gastrointestinal tract. This raises the need to develop a screening technique capable of detecting isolated nanosized particles in biological tissues. Herein, the potential of a cellulose-binding module fused to a green fluorescent protein (GFP-CBM) to detect single bacterial cellulose nanocrystals (BCNC) obtained by acid hydrolysis was assessed. Adsorption studies were performed to characterize the interaction of GFP-CBM with BNC and BCNC. Correlative electron light microscopy was used to demonstrate that isolated BCNC may be detected by fluorescence microscopy. The uptake of BCNC by macrophages was also assessed. Finally, an exploratory 21-day repeated-dose study was performed, wherein Wistar rats were fed daily with BNC. The presence of BNC or BCNC throughout the GIT was observed only in the intestinal lumen, suggesting that cellulose particles were not absorbed. While a more comprehensive toxicological study is necessary, these results strengthen the idea that BNC can be considered a safe food additive.

A "turn-off" fluorescent sensor based on electrospun polycaprolactone nanofibers and fluorene(bisthiophene) derivative for nitroaromatic explosive detection.

The preparation of fluorene(bisthiophene)-based fluorescent nanofibers for nitroaromatic explosive detection provides a convenient rapid and low-cost strategy aiming at forensic applications. Polycaprolactone (PCL) and fluorene(bisthiophene) derivative (FBT) nanofibers were obtained by electrospinning technique as a free-standing mat and characterized by SEM, FTIR, thermal analysis and fluorescence spectroscopy. The PCL/FBT nanofibers presented high sensitivity towards 2,4,6-trinitrotoluene (TNT) and picric acid (PA), with fluorescence quenching (turn-off mechanism), and selectivity to another kind of explosives. The free-standing mats were used as a cloth strip that was swiped on surfaces contaminated with TNT traces allowing its visual detection under UV light source. These findings are particularly important for the development of a facile and promising strategy to assembly portable optical devices for nitroaromatic explosive detection.

Horseradish Peroxidase-Crosslinked Calcium-Containing Silk Fibroin Hydrogels as Artificial Matrices for Bone Cancer Research.

Hydrogels, being capable of mimicking the extracellular matrix composition of tissues, are greatly used as artificial matrices in tissue engineering applications. In this study, the generation of horseradish peroxidase (HRP)-crosslinked silk fibroin (SF) hydrogels, using calcium peroxide as oxidizer is reported. The proposed fast forming calcium-containing SF hydrogels spontaneously undergo SF conformational changes from random coil to ß-sheet during time, exhibiting ionic, and pH stimuli responsiveness. In vitro response shows calcium-containing SF hydrogels' encapsulation properties and their ability to promote SaOs-2 tumor cells death after 10 days of culturing, upon complete ß-sheet conformation transition. Calcium-containing SF hydrogels' angiogenic potential investigated in an in ovo chick chorioallantoic membrane (CAM) assay, show a high number of converging blood vessels as compared to the negative control, although no endothelial cells infiltration is observed. The in vivo response evaluated in subcutaneous implantation in CD1 and nude NCD1 mice shows that calcium-containing SF hydrogels are stable up to 6 weeks after implantation. However, an increased number of dead cells are also present in the surrounding tissue. The results suggest the potential of calcium-containing SF hydrogels to be used as novel in situ therapeutics for bone cancer treatment applications, particularly to osteosarcoma.

Microfluidics for Angiogenesis Research.

Angiogenesis is a natural and vital phenomenon of neovascularization that occurs from pre-existing vasculature, being present in many physiological processes, namely in development, reproduction and regeneration. Being a highly dynamic and tightly regulated process, its abnormal expression can be on the basis of several pathologies. For that reason, angiogenesis has been a subject of major interest among the scientific community, being transverse to different areas and founding particular attention in tissue engineering and cancer research fields. Microfluidics has emerged as a powerful tool for modelling this phenomenon, thereby surpassing the limitations associated to conventional angiogenic models. Holding a tremendous flexibility in terms of experimental design towards a specific goal, microfluidic systems can offer an unlimited number of opportunities for investigating angiogenesis in many relevant scenarios, namely from its fundamental comprehension in normal physiological processes to the identification and testing of new therapeutic targets involved on pathological angiogenesis. Additionally, microvascular 3D in vitro models are now opening up new prospects in different fields, being used for investigating and establishing guidelines for the development of next generation of 3D functional vascularized grafts. The promising applications of this emerging technology in angiogenesis studies are herein overviewed, encompassing fundamental and applied research.

Enhanced performance of chitosan/keratin membranes with potential application in peripheral nerve repair.

Although surgical management of peripheral nerve injuries (PNIs) has improved over time, autografts are still the current "gold standard" treatment for PNIs, which presents numerous limitations. In an attempt to improve natural biomaterial-based nerve guidance conduits (NGCs), chitosan (CHT), a derivative of the naturally occurring biopolymer chitin, has been explored for peripheral nerve regeneration (PNR). In addition to CHT, keratin has gained enormous attention as a biomaterial and tissue engineering scaffolding. In this study, biomimetic CHT/keratin membranes were produced using a solvent casting technique. These membranes were broadly characterized in terms of their surface topography and physicochemical properties, with techniques such as Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), contact angle, weight loss and water uptake measurements, Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Biological in vitro assays were also performed, where a preliminary cytotoxicity screening with the L929 fibroblast cell line revealed that the membranes and respective materials are suitable for cell culture. In addition, Schwann cells, fibroblasts and endothelial cells were directly seeded in the membranes. Quantitative and qualitative assays revealed that the addition of keratin enhanced cell viablity and adhesion. Based on the encouraging in vitro results, the in vivo angiogenic/antiangiogenic potential of CHT and CHT/keratin membranes was assessed, using an optimized chick embryo chorioallantoic membrane assay, where higher angiogenic responses were seen in keratin-enriched materials. Overall, the obtained results indicate the higher potential of CHT/keratin membranes for guided tissue regeneration applications in the field of PNR.

Injectable and tunable hyaluronic acid hydrogels releasing chemotactic and angiogenic growth factors for endodontic regeneration.

Bioengineered soft tissues on any meaningful scale or complexity must incorporate aspects of the functional tissue, namely a vasculature, providing cells oxygen and nutrients critical for their survival. However, the ability of tissue engineering strategies to promote a fast revascularization is critically limited. Particularly in endodontic regenerative therapies, the complicated anatomy of the root canal system, and the narrow apical access limit the supply of new blood vessels and pulp tissue ingrowth. Here we characterize the viscoelastic and microstructural properties of a class of injectable hyaluronic acid (HA) hydrogels formed in situ, reinforced with cellulose nanocrystals (CNCs) and enriched with platelet lysate (PL), and test its ability to promote cells recruitment and proangiogenic activity in vitro. The incorporation of CNCs enhanced the stability of the materials against hydrolytic and enzymatic degradation. Moreover, the release of the chemotactic and pro-angiogenic growth factors (GFs) (PDGF and VEGF) from the PL-laden hydrogels showed an improved sustained profile proportional to the amount of incorporated CNCs. The PL-laden hydrogels exhibited preferential supportive properties of encapsulated human dental pulp cells (hDPCs) in in vitro culture conditions. Finally, PL-laden hydrogels stimulated chemotactic and pro-angiogenic activity by promoting hDPCs recruitment and cell sprouting in hDPCs/human umbilical vein endothelial cell co-cultures in vitro, and in an ex vivo model. These results support the use of the combined system as a scaffold for GFs delivery and cells recruitment, thereby exhibiting great clinical potential in treating injuries in vascularized tissues. STATEMENT OF SIGNIFICANCE: Innovative strategies for improved chemotactic and pro-angiogenic features of TE constructs are needed. In this study, we developed an injectable HA/CNC/PL hydrogel with improved structural and biologic properties, that not only provide a sustained release of chemotactic and proangiogenic GFs from PL but also enhance the cells' viability and angiogenic activity. As a result of their unique traits, the developed hydrogels are ideally suited to simultaneously act as a GFs controlled delivery system and as a supportive matrix for cell culture, recruitment, and revascularization induction, holding great potential for the regeneration of vascularized soft tissues, such as the dentin-pulp complex.

Gellan Gum-Based Hydrogels for Osteochondral Repair.

Gellan gum (GG) is a widely explored natural polysaccharide that has been gaining attention in tissue engineering (TE) and regenerative medicine field, and more recently in osteochondral TE approaches. Taking advantage of its inherent features such as biocompatibility, biodegradability, similarity with the extracellular matrix and easy functionalization, GG-based hydrogels have been studied for their potential for cartilage and bone tissue regeneration. Several preclinical studies describe the successful outcome of GG in cartilage tissue engineering. By its turn, GG composites have also been proposed in several strategies to guide bone formation. The big challenge in osteochondral TE approaches is still to achieve cartilage and bone regeneration simultaneously through a unique integrated bifunctional construct. The potential of GG to be used as polymeric support to reach both bone and cartilage regeneration has been demonstrated. This chapter provides an overview of GG properties and the functionalization strategies employed to tailor its behaviour to a particular application. The use of GG in soft and hard tissues regeneration approaches, as well in osteochondral integrated TE strategies is also revised.

Surface physical chemistry properties in coated bacterial cellulose membranes with calcium phosphate.

Bacterial cellulose has become established as a new biomaterial, and it can be used for medical applications. In addition, it has called attention due to the increasing interest in tissue engineering materials for wound care. In this work, the bacterial cellulose fermentation process was modified by the addition of chondroitin sulfate to the culture medium before the inoculation of the bacteria. The biomimetic process with heterogeneous calcium phosphate precipitation of biological interest was studied for the guided regeneration purposes on bacterial cellulose. FTIR results showed the incorporation of the chondroitin sulfate in the bacterial cellulose, SEM images confirmed the deposition of the calcium phosphate on the bacterial cellulose surface, XPS analysis showed a selective chemical group influences which change calcium phosphate deposition, besides, the calcium phosphate phase with different Ca/P ratios on bacterial cellulose surface influences wettability. XTT results concluded that these materials did not affect significantly in the cell viability, being non-cytotoxic. Thus, it was produced one biomaterial with the surface charge changes for calcium phosphate deposition, besides different wettability which builds new membranes for Guided Tissue Regeneration.

Sheep milk: physical-chemical characteristics and microbiological quality / Leite ovino: características físico-químicas e qualidade microbiológica

Sheep milk is the third most consumed milk in Brazil. It is much appreciated for its nutritional status and is important for children that have problems with cow milk. Little information is known about the chemical, physical and microbiological composition of sheep milk from South Brazil. Thus, the aim of this study was to describe chemical and microbiological characteristics of sheep milk produced on two rural properties located in southern Brazil (Paraná and Rio Grande do Sul). The chemical composition of sheep milk was 17.32 g/100 g total solids, 5.86 g/100 g total protein, 4.46 g/100 g casein, 1.08 g/100 g whey protein, 7.28 g/100 g fat, 0.93 g/100 g ash, and 3.41 g/100 g lactose. High somatic cell count (1.7x106 cells/mL), total mesophilic bacterias (16.0x106 CFU/mL) and psychrotrophics (5.8x106 CFU/mL) were observed. Growth of Staphylococcus aureus, enterobacteria and coliforms occurred in 100% of the samples, and 45% of the samples showed growth of Escherichia coli. The sheep milk physical-chemical and microbiology parameters are similar to those presented in the literature for other countries but somatic cell count presented high levels.

O leite de ovelha é o terceiro mais consumido no Brasil, e é muito apreciado devido ao seu aspecto nutricional. Pouca informação a respeito da composição química e microbiológica do leite de ovelha no Brasil é conhecida. O objetivo deste trabalho foi caracterizar o leite ovino produzido em duas propriedades rurais localizadas no Sul do Brasil (Paraná e Rio Grande do Sul). A composição química do leite de ovelha foi 17,32 g/100 g de sólidos totais; 5,86 g/100 g de proteína total; 4,46 g/100 g de caseína; 1,08 g/100 g de soro proteico; 7,28 g/100 g de gordura; 0,93 g/100 g de cinzas e 3.41 g/100 g de lactose. Altas contagens de células somáticas (1,7x106 células/mL), bactérias mesófilas (16,0 x106 UFC/mL) e psicrotróficos (5,8x106 UFC/mL) foram observadas. Multiplicação de Staphylococcus aureus, enterobactérias e coliformes ocorreu em 100% das amostras, 45% de amostras apresentou multiplicação de Escherichia coli. Os parâmetros físico-químicos e microbiológicos do leite ovino deste estudo são semelhantes a literatura para outros países, porém, a contagem de células somáticas foi elevada.

Sheep milk: physical-chemical characteristics and microbiological quality.

Sheep milk is the third most consumed milk in Brazil. It is much appreciated for its nutritional status and is important for children that have problems with cow milk. Little information is known about the chemical, physical and microbiological composition of sheep milk from South Brazil. Thus, the aim of this study was to describe chemical and microbiological characteristics of sheep milk produced on two rural properties located in southern Brazil (ParanA and Rio Grande do Sul). The chemical composition of sheep milk was 17.32 g/100 g total solids, 5.86 g/100 g total protein, 4.46 g/100 g casein, 1.08 g/100 g whey protein, 7.28 g/100 g fat, 0.93 g/100 g ash, and 3.41 g/100 g lactose. High somatic cell count (1.7x106 cells/mL), total mesophilic bacterias (16.0 x 106 CFU/mL) and psychrotrophics (5.8 x 106 CFU/mL) were observed. Growth of Staphylococcus aureus, enterobacteria and coliforms occurred in 100% of the samples, and 45% of the samples showed growth of Escherichia coli. The sheep milk physical-chemical and microbiology parameters are similar to those presented in the literature for other countries but somatic cell count presented high levels.

Novel chemically modified bacterial cellulose nanocomposite as potential biomaterial for stem cell therapy applications.

Bacterial cellulose (BC) has become established as a remarkably versatile biomaterial and can be used in a wide variety of applied scientific applications, especially for medical devices. In this work, the bacterial cellulose fermentation process is modified by the addition of hyaluronic acid and gelatin (1% w/w) to the culture medium before the bacteria is inoculated. Hyaluronic acid and gelatin influence in bacterial cellulose was analyzed using Transmission Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Adhesion and viability studies with human dental pulp stem cells using natural bacterial cellulose/hyaluronic acid as scaffolds for regenerative medicine are presented for the first time in this work. MTT viability assays show higher cell adhesion in bacterial cellulose/gelatin and bacterial cellulose/ hyaluronic acid scaffolds over time with differences due to fiber agglomeration in bacterial cellulose/gelatin. Confocal microscopy images showed that the cell were adhered and well distributed within the fibers in both types of scaffolds.

Novel electrospun nanotholits/PHB scaffolds for bone tissue regeneration.

Nanotholits is an osteoinductor or be, stimulates the bone regeneration, enabling bigger migration of the cells for formation of the bone tissue regeneration mainly because nanotholits are rich in minerals considered essential to the bone mineralization process on a protein matrix (otolin) as hydroxiapatite. In order to improve its biodegrability and bioresorption in new platforms for tissue engineering, it was electrospun PHB/nanotholits from aqueous solutions of this polymer at concentrations of nanotholits 1% (w/v) and compared morphological and thermal properties with PHB/nanotholits casting films. Electrospun PHB/nanotholits mats presents more symmetric nanopore structure than casting films mats observed by SEM images mainly because the orientation of pores along the longitudinal direction of the electrospun fibers. Nanotholits influences in PHB electrospun/casting was analyzed using transmission infrared spectroscopy (FTIR). TGA showed similar thermal properties but DSC showed distinct thermal properties and crystallinity process of the developed bionanocomposite mainly because of different processing.

Human dental pulp stem cell behavior using natural nanotolith/bacterial cellulose scaffolds for regenerative medicine.

Adhesion and Viability study with human dental pulp stem cell using natural nanotolith/bacterial cellulose scaffolds for regenerative medicine are presented at first time in this work. Nanotolith, are osteoinductors, i.e., they stimulate bone regeneration, enabling higher cells migration for bone tissue regeneration formation. This is mainly because nanotoliths are rich minerals present in the internal ear of bony fish. In addition, are part of a system which acts as a depth sensor and balance, acting as a sound vibrations detector and considered essential for the bone mineralization process, as in hydroxiapatites. Nanotoliths influence in bacterial cellulose was analyzed using transmission infrared spectroscopy (FTIR). Results shows that fermentation process and nanotoliths agglomeration decrease initial human dental pulp stem cell adhesion however tested bionanocomposite behavior has cell viability increase over time.

Antimicrobial susceptibility of Neisseria gonorrhoeae isolates from patients attending a public referral center for sexually transmitted diseases in Belo Horizonte, State of Minas Gerais, Brazil.

INTRODUCTION: The aim of this study was to determine the antimicrobial susceptibility of Neisseria gonorrhoeae isolates obtained from patients attending a public referral center for sexually transmitted diseases and specialized care services (STD/SCS) in Belo Horizonte, Brazil. METHODS: Between March 2011 and February 2012, 201 specimens of Neisseria gonorrhoeae were consecutively obtained from men with symptoms of urethritis and women with symptons of cervicitis or were obtained during their initial consultation. The strains were tested using the disk diffusion method, and the minimum inhibitory concentrations of azithromycin, cefixime, ceftriaxone, ciprofloxacin, chloramphenicol, penicillin, tetracycline and spectinomycin were determined using the E-test. RESULTS: The specimens were 100% sensitive to cefixime, ceftriaxone and spectinomycin and exhibited resistances of 4.5% (9/201), 21.4% (43/201), 11.9% (24/201), 22.4% (45/201) and 32.3% (65/201) to azithromycin, ciprofloxacin, chloramphenicol, penicillin and tetracycline, respectively. Intermediate sensitivities of 17.9% (36/201), 4% (8/201), 16.9% (34/201), 71.1% (143/201) and 22.9% (46/201) were observed for azithromycin, ciprofloxacin, chloramphenicol, penicillin and tetracycline, respectively. The specimens had plasmid-mediated resistance to penicillin PPNG 14.5% (29/201) and tetracycline TRNG 11.5% (23/201). CONCLUSIONS: The high percentage of detected resistance to penicillin, tetracycline, chloramphenicol and ciprofloxacin indicates that these antibiotics are not appropriate for gonorrhea treatment at the Health Clinic and possibly in Belo Horizonte. The resistance and intermediate sensitivity of these isolates indicates that caution is recommended in the use of azithromycin and emphasizes the need to establish mechanisms for the surveillance of antimicrobial resistance for the effective control of gonorrhea.

Antimicrobial susceptibility of Neisseria gonorrhoeae isolates from patients attending a public referral center for sexually transmitted diseases in Belo Horizonte, State of Minas Gerais, Brazil

Introduction The aim of this study was to determine the antimicrobial susceptibility of Neisseria gonorrhoeae isolates obtained from patients attending a public referral center for sexually transmitted diseases and specialized care services (STD/SCS) in Belo Horizonte, Brazil. Methods Between March 2011 and February 2012, 201 specimens of Neisseria gonorrhoeae were consecutively obtained from men with symptoms of urethritis and women with symptons of cervicitis or were obtained during their initial consultation. The strains were tested using the disk diffusion method, and the minimum inhibitory concentrations of azithromycin, cefixime, ceftriaxone, ciprofloxacin, chloramphenicol, penicillin, tetracycline and spectinomycin were determined using the E-test. Results The specimens were 100% sensitive to cefixime, ceftriaxone and spectinomycin and exhibited resistances of 4.5% (9/201), 21.4% (43/201), 11.9% (24/201), 22.4% (45/201) and 32.3% (65/201) to azithromycin, ciprofloxacin, chloramphenicol, penicillin and tetracycline, respectively. Intermediate sensitivities of 17.9% (36/201), 4% (8/201), 16.9% (34/201), 71.1% (143/201) and 22.9% (46/201) were observed for azithromycin, ciprofloxacin, chloramphenicol, penicillin and tetracycline, respectively. The specimens had plasmid-mediated resistance to penicillin PPNG 14.5% (29/201) and tetracycline TRNG 11.5% (23/201). Conclusions The high percentage of detected resistance to penicillin, tetracycline, chloramphenicol and ciprofloxacin indicates that these antibiotics are not appropriate for gonorrhea treatment at the Health Clinic and possibly in Belo Horizonte. The resistance and intermediate sensitivity of these isolates indicates that caution is recommended in the use of azithromycin and emphasizes the need to establish mechanisms for the surveillance of antimicrobial resistance for the effective control of gonorrhea. .

Breast cancer presents with a paraneoplastic neurologic syndrome.

BACKGROUND: Paraneoplastic neurologic syndromes (PNS) pose quite an uncommon neurological complication, affecting less than 1% of patients with breast cancer. Nearly one third of these patients lack detectable onconeural antibodies (ONAs), and improvement in neurologic deficits with concomitant cancer treatments is achieved in less than 30% of cases. CASE PRESENTATION: A 42-year-old, premenopausal woman presented with facial paralysis on the central left side accompanied by a left tongue deviation, an upward vertical nystagmus, moderate spastic paraparesis, dystonic posturing of the left foot, lower limb hyperreflexia and bilateral extensor plantar reflex. After ruling out all other potential neurologic causes, PNS was suspected but no ONAs were found. A PET-CT scan detected increased metabolism in the right breast, as well as an ipsilateral thoracic interpectoral adenopathy. Core biopsy confirmed the presence of an infiltrating duct carcinoma. After breast surgery, the neurologic symptoms disappeared. One week later, the patient was readmitted to the hospital with a bilateral fatigable eyelid ptosis, and two weeks later, there was a noticeable improvement in eyelid ptosis, accompanied by a rapid and progressive development of lower spastic paraparesis. She started adjuvant treatment with chemotherapy with marked clinical and neurological improvement, and by the end of radiotherapy, there were no signs of neurologic impairment. CONCLUSION: This case study highlights the importance of a high level of vigilance for the detection of PNS, even when ONAs are not detected, as the rapid identification and treatment of the underlying tumor offers the best chance for a full recovery.

Caretaking behavior among siblings in children's shelters / Comportamento de cuidado entre irmãos em instituição de abrigo

This study analyzed 742 events involving caretaking behavior among sheltered children with or without siblings in the same institution. Statistical tests were used for intergroup evaluation in comparison to focal subjects. Children with siblings showed a greater number of those behaviors and they were primarily directed to non-sibling peers (roommates) or adults (caretakers). The study also revealed that the caretaking behavior was more frequent in the group of children with siblings in the institution whereas those without siblings showed a more affective contact and behaviors directed more to adults than to peers. It was concluded that the caretaking behavior is present among siblings, but it assumes particular shapes because of the complex social dynamics that characterize the research environment.

Este estudo analisou 742 eventos envolvendo comportamento de cuidado entre crianças abrigadas com e sem irmão na mesma instituição. Foram aplicados testes estatísticos para avaliação intergrupal na comparação entre os sujeitos focais. As crianças com irmão manifestaram a maior proporção desses comportamentos e foram dirigidos principalmente a parceiros não-Irmãos (companheiros de dormitório) ou adultos (cuidadores). O estudo revelou ainda que o comportamento Brincar de cuidar foi mais freqüente no grupo de crianças Com Irmão na instituição enquanto que entre os participantes Sem Irmão predominou Estabelecer contato afetuoso e comportamentos direcionados mais a adultos do que aos pares. Conclui-se que o comportamento de cuidado está presente entre irmãos, mas assume formas particulares em razão da complexa dinâmica social que caracteriza o ambiente pesquisado.

Percepção de educadores de abrigo: o seu trabalho e a criança institucionalizada / The perception of shelter care educators: their work and the institutionalized child

Este artigo objetiva analisar a percepção de cuidadores de abrigo acerca do trabalho desenvolvido por eles e sobre as crianças institucionalizadas. Foram aplicados questionários a 102 educadoras do maior abrigo de Belém, entre 2004 e 2006. Os resultados mostraram que para os educadores: o atendimento da instituição é satisfatório com cuidados físicos básicos, mas não com questões afetivas e intelectuais; a criança institucionalizada não possui liberdade de fazer escolhas, não tem privacidade, nem atenção individualizada; o trabalho desses profissionais exerce pouca influência sobre o desenvolvimento cognitivo e afetivo infantil. Essas informações podem ser úteis na elaboração do projeto político pedagógico da instituição, enfatizando a unidade entre cuidar e educar.

Determination of the drag coefficient during the first and second gliding positions of the breaststroke underwater stroke.

The purpose of the current study was to assess and to compare the hydrodynamics of the first and second gliding positions of the breaststroke underwater stroke used after starts and turns, considering drag force (D), drag coefficient (CD) and cross-sectional area (S). Twelve national-level swimmers were tested (6 males and 6 females, respectively 18.2±4.0 and 17.3±3.0 years old). Hydrodynamic parameters were assessed through inverse dynamics from the velocity to time curve characteristic of the underwater armstroke of the breaststroke technique. The results allow us to conclude that, for the same gliding velocities (1.37±0.124 m/s), D and the swimmers' S and CD values obtained for the first gliding position are significantly lower than the corresponding values obtained for the second gliding position of the breaststroke underwater stroke (31.67±6.44 N vs. 46.25±7.22 N; 740.42±101.89 cm2 vs. 784.25±99.62 cm2 and 0.458±0.076 vs. 0.664±0.234, respectively). These differences observed for the total sample were not evident for each one of the gender's subgroups.