Immune response deviation and enhanced expression of chemokine receptor CCR4 in TBI patients due to unknown serum factors

BACKGROUND: Severe brain trauma leads to an activation of the immune system. To this date, neither the exact perturbation of the specific immune reaction induced by the traumatic brain injury (TBI), nor the interactions leading to the infiltration of peripheral immune cells into the brain are fully understood. PATIENTS AND METHODS: Serum was collected from 17 patients with TBI and a long bone fracture, 24 patients with an isolated long bone fracture and from healthy individuals. The effect of the serum on normal human monocytes and T-lymphocytes was tested in vitro by assessing proliferation and expression of surface markers, chemokine receptors and cytokines. RESULTS: Serum collected from patients with a TBI and a long bone fracture increased the expression of the chemokine receptor CCR4 in monocytes when compared to patients with an isolated long bone fracture. Extending this comparison to T-lymphocytes, the serum from TBI patients induced lower proliferation rates and decreased expression of the pro-inflammatory cytokine TNF-alpha, while simultaneously increasing the secretion of immune-modulatory cytokines (IL-4, IL-10 and TGF-beta) (p<0.05). CONCLUSION: Patients with a TBI release currently unknown soluble factors into the circulating blood that up regulate expression of chemokine receptor CCR4 in peripheral blood monocytes whilst concurrently inducing expression of immunosuppressive cytokines by activated T-lymphocytes.

Nail surgery

Nail surgery is a special branch of hand and dermatologic surgery. It is not widely performed, and many physicians do not feel at ease to perform it. The objective of this contribution is to give a short overview of the most important surgical procedures in clinical practice. References from the literature and the author's own experiences are condensed to describe what a dermatologic practitioner with knowledge of the nail and some surgical skills can perform. Nail surgery is a precise technique that requires careful administration and attention to details. Proper patient preparation starts with a patient history to identify potential contraindications and to prevent unnecessary complications. The author recommends isopropyl alcohol scrub and chlorhexidine for disinfection and ropivacaine 1% for anesthesia. The technique used for anesthesia depends on the type of surgery. Surgical procedures are described for diagnostic biopsies, nail avulsion in general, onychogryposis, paronychia treatment, hematomas and bone fracture due to trauma, removal of subungual foreign bodies, ingrowing nails, pincer nails, warts, ungual fibrokeratomas, digital myxoid pseudocyst, subungual exostoses, and various tumors. If performed correctly with adequate skills, nail surgery will lead to functionally and aesthetically satisfying results in the majority of instances.

Risk factors associated with cast complications in horses: 398 cases (1997-2006)

OBJECTIVE To determine the frequency of and risk factors for complications associated with casts in horses. DESIGN Multicenter retrospective case series. ANIMALS 398 horses with a half-limb or full-limb cast treated at 1 of 4 hospitals. PROCEDURES Data collected from medical records included age, breed, sex, injury, limb affected, time from injury to hospital admission, surgical procedure performed, type of cast (bandage cast [BC; fiberglass tape applied over a bandage] or traditional cast [TC; fiberglass tape applied over polyurethane resin-impregnated foam]), limb position in cast (flexed, neutral, or extended), and complications. Risk factors for cast complications were identified via multiple logistic regression. RESULTS Cast complications were detected in 197 of 398 (49%) horses (18/53 [34%] horses with a BC and 179/345 [52%] horses with a TC). Of the 197 horses with complications, 152 (77%) had clinical signs of complications prior to cast removal; the most common clinical signs were increased lameness severity and visibly detectable soft tissue damage Cast sores were the most common complication (179/398 [45%] horses). Casts broke for 20 (5%) horses. Three (0.8%) horses developed a bone fracture attributable to casting Median time to detection of complications was 12 days and 8 days for horses with TCs and BCs, respectively. Complications developed in 71%, 48%, and 47% of horses with the casted limb in a flexed, neutral, and extended position, respectively. For horses with TCs, hospital, limb position in the cast, and sex were significant risk factors for development of cast complications. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that 49% of horses with a cast developed cast complications.

Development of a balanced experimental–computational approach to understanding the mechanics of proximal femur fractures

The majority of people who sustain hip fractures after a fall to the side would not have been identified using current screening techniques such as areal bone mineral density. Identifying them, however, is essential so that appropriate pharmacological or lifestyle interventions can be implemented. A protocol, demonstrated on a single specimen, is introduced, comprising the following components; in vitro biofidelic drop tower testing of a proximal femur; high-speed image analysis through digital image correlation; detailed accounting of the energy present during the drop tower test; organ level finite element simulations of the drop tower test; micro level finite element simulations of critical volumes of interest in the trabecular bone. Fracture in the femoral specimen initiated in the superior part of the neck. Measured fracture load was 3760 N, compared to 4871 N predicted based on the finite element analysis. Digital image correlation showed compressive surface strains as high as 7.1% prior to fracture. Voxel level results were consistent with high-speed video data and helped identify hidden local structural weaknesses. We found using a drop tower test protocol that a femoral neck fracture can be created with a fall velocity and energy representative of a sideways fall from standing. Additionally, we found that the nested explicit finite element method used allowed us to identify local structural weaknesses associated with femur fracture initiation.

Stem cells in the periodontal ligament

The ability to identify and manipulate stem cells has been a significant advancement in regenerative medicine and has contributed to the development of tissue engineering-based clinical therapies. Difficulties associated with achieving predictable periodontal regeneration, means that novel techniques such as tissue engineering need to be developed in order to regenerate the extensive soft and hard tissue destruction that results from periodontitis. One of the critical requirements for a tissue engineering approach is the delivery of ex vivo expanded progenitor populations or the mobilization of endogenous progenitor cells capable of proliferating and differentiating into the required tissues. By definition, stem cells fulfill these requirements and the recent identification of stem cells within the periodontal ligament represents a significant development in the progress toward predictable periodontal regeneration. In order to explore the importance of stem cells in periodontal wound healing and regeneration, this review will examine contemporary concepts in stem cell biology, the role of periodontal ligament progenitor cells in the regenerative process, recent developments in identifying periodontal stem cells and the clinical implications of these findings.

A aplicação de plasma rico em plaquetas na regeneração dos tecidos periodontais

O periodonto é uma unidade biológica e funcional, constituída pela gengiva, pelo cemento, pelo ligamento periodontal e pelo osso alveolar. O seu processo de cicatrização envolve mecanismos fisiológicos complexos que requerem a ação dos fatores de crescimento, péptidos oriundos da desgranulação das plaquetas. Neste sentido surge o Plasma Rico em Plaquetas como um produto autólogo, obtido a partir da centrifugação do sangue do próprio paciente e que visa melhorar a cicatrização dos tecidos após procedimentos enquadrados na Medicina Dentária. Esta revisão bibliográfica baseou-se numa pesquisa realizada na base de dados MEDLINE, via pubmed. Foram utilizadas as palavras-chave “plasma rich in growth factors”, “platelet-rich plasma”, “oral surgery”, “dental implants”, “sinus lift”, “third molar surgery” e “bone regeneration”. Após leitura de 40 artigos, foram descartados 9 pela sua pouca relevância no contexto. O objetivo é avaliar a efetividade da aplicação de plasma rico em plaquetas na regeneração dos tecidos periodontais em situações clínicas como alvéolos pós-extracionais, cirurgias de implantes, cirurgias de elevação do seio maxilar e na regeneração óssea. A efetividade em tecidos moles parece ser consensual. A efetividade no tecido ósseo é alvo de contradição entre os diversos autores, concluindo-se que há necessidade de mais estudos randomizados e controlados para que se possa responder à questão com evidência científica suficiente.

Fraturas dentárias

Uma lesão traumática é, a seguir à cárie dentária, um dos problemas mais comuns da saúde oral. O traumatismo dentário consiste numa agressão que afeta os dentes ou os tecidos de suporte, podendo levar ao rompimento do ligamento periodontal, fratura dentária, fratura óssea ou alterações pulpares. Este problema causa desconforto físico, emocional e comprometimento estético. Quando os traumatismos afetam os tecidos duros ou polpa denominam-se de fraturas dentárias. Estas podem ser divididas em fraturas coronárias de esmalte; fraturas coronárias de esmalte e dentina sem exposição pulpar; fraturas coronárias de esmalte e dentina com exposição pulpar; fraturas corono-radiculares de esmalte, dentina e cemento sem exposição pulpar; fraturas corono-radiculares com exposição pulpar e fratura radicular envolvendo cemento, dentina e polpa. O objetivo deste trabalho monográfico foi fazer uma revisão bibliográfica de estudos científicos sobre fraturas dentárias. Assim, serão abordados os diversos tipos de fraturas dentárias, as suas etiologias, prevalências e fatores associados, também definir planos de tratamento, técnicas de restauração direta de fraturas coronárias e possíveis medidas de prevenção. A pesquisa bibliográfica para esta revisão foi realizada em bases eletrónicas de referência como Pubmed, Scielo, selecionando artigos entre os anos 2006 e 2016. Foram também utilizados como elementos de pesquisa o site Dental Trauma Guide (DTG), o site International Association of Dental Traumatology (IADT), livros da especialidade existentes na Biblioteca da Universidade Fernando Pessoa que embora com datas de publicação mais antigas (2001) foram imprescindíveis para o desenvolvimento da monografia. A pesquisa foi realizada em duas línguas, português e inglês. Como conclusão pode-se dizer que nos dias de hoje, o médico dentista tem muitas opções de tratamento de dentes fraturados. Para restaurar a fratura o médico pode optar por colar o fragmento, restaurar usando uma matriz guia ou restaurar à mão livre. A escolha da técnica deve ser estudada de acordo com cada paciente e suas expectativas.

Use of GLP-1 mimetic in type 2 diabetes mellitus: is it the end of fragility fractures?

International audience

Clínica e cirurgia de equinos

O presente relatório de conclusão do curso de Mestrado Integrado em Medicina Veterinária da Universidade de Évora é baseado no estágio curricular realizado no hospital de equinos “Pferdeklinik in Kirchheim” na Alemanha e em clínica ambulatória com a Dra. Rita Rocha Pires na zona da Grande Lisboa e no concurso de saltos de obstáculos internacional de Vilamoura. O presente relatório é dividido em duas partes. A primeira parte apresenta a casuística nos dois locais do estágio e descreve alguns dos casos clínicos e cirúrgicos acompanhados nas diferentes áreas da clínica de equinos. A segunda parte aborda uma monografia sobre as vantagens e desvantagens de diferentes tipos de tratamento de fraturas completas do terceiro osso do metacarpo/tarso e apresenta um caso clinico de fratura cominutiva do terceiro osso do metatarso, o qual foi acompanhado durante o estágio na Alemanha; EQUINE CLINICS AND SURGERY ABSTRACT: The present report is based on the curricular internship, integrated on the Master´s degree in veterinary medicine at the University of Évora, which took place at the equine hospital “Pferdeklinik in Kirchheim” in Germany and at outpatient clinic with Dr. Rita Rocha Pires in the Greater Lisbon area and at the international show jumping competition in Vilamoura. This report is divided into two sections. The first section presents the casuistry at the two internship sites and describes some of the clinical and surgical cases followed in different areas of equine clinics. The second section develops a monograph on the advantages and disadvantages of different types of treatment for complete third metacarpal/tarsal bone fractures and presents a clinical case of a comminuted third metatarsal bone fracture, which was accompanied during the internship in Germany.

Instability prolongs the chondral phase during bone healing in sheep

In this sheep study, we investigated the influence of fixation stability on the temporal and spatial distribution of tissues in the fracture callus. As the initial mechanical conditions have been cited as being especially important for the healing outcome, it was hypothesized that differences in the path of healing would be seen as early as the initial phase of healing. ----- ----- Sixty-four sheep underwent a mid-shaft tibial osteotomy that was treated with either a rigid or a semi-rigid external fixator. Animals were sacrificed at 2, 3, 6 and 9 weeks postoperatively and the fracture calluses were analyzed using radiological, biomechanical and histological techniques. Statistical comparison between the groups was performed using the Mann–Whitney U test for unpaired non-parametric data. ----- ----- In the callus of the tibia treated with semi-rigid fixation, remnants of the fracture haematoma remained present for longer, although new periosteal bone formation during early healing was similar in both groups. The mechanical competence of the healing callus at 6 weeks was inferior compared to tibiae treated with rigid fixation. Semi-rigid fixation resulted in a larger cartilage component of the callus, which persisted longer. Remodeling processes were initiated earlier in the rigid group, while new bone formation continued throughout the entire investigated period in the semi-rigid group. ----- ----- In this study, evidence is provided that less rigid fixation increased the time required for healing. The process of intramembranous ossification appeared during the initial stages of healing to be independent of mechanical stability. However, the delay in healing was related to a prolonged chondral phase.

A new model to study healing of a complex femur fracture with concurrent soft tissue injury in sheep

High energy bone fractures resulting from impact trauma are often accompanied by subcutaneous soft tissue injuries, even if the skin remains intact. There is evidence that such closed soft tissue injuries affect the healing of bone fractures, and vice versa. Despite this knowledge, most impact trauma studies in animals have focussed on bone fractures or soft tissue trauma in isolation. However, given the simultaneous impact on both tissues a better understanding of the interaction between these two injuries is necessary to optimise clinical treatment. The aim of this study was therefore to develop a new experimental model and characterise, for the first time, the healing of a complex fracture with concurrent closed soft tissue trauma in sheep. A pendulum impact device was designed to deliver a defined and standardised impact to the distal thigh of sheep, causing a reproducible contusion injury to the subcutaneous soft tissues. In a subsequent procedure, a reproducible femoral butterfly fracture (AO C3-type) was created at the sheep’s femur, which was initially stabilised for 5 days by an external fixator construct to allow for soft tissue swelling to recede, and ultimately in a bridging construct using locking plates. The combined injuries were applied to twelve sheep and the healing observed for four or eight weeks (six animals per group) until sacrifice. The pendulum impact led to a moderate to severe circumferential soft tissue injury with significant bruising, haematomas and partial muscle disruptions. Posttraumatic measurements showed elevated intra-compartmental pressure and circulatory tissue breakdown markers, with recovery to normal, pre-injury values within four days. Clinically, no neurovascular deficiencies were observed. Bi-weekly radiological analysis of the healing fractures showed progressive callus healing over time, with the average number of callus bridges increasing from 0.4 at two weeks to 4.2 at eight weeks. Biomechanical testing after sacrifice showed increasing torsional stiffness between four and eight weeks healing time from 10% to 100%, and increasing ultimate torsional strength from 10% to 64% (relative to the contralateral control limb). Our results demonstrate the robust healing of a complex femur fracture in the presence of a severe soft tissue contusion injury in sheep and demonstrate the establishment of a clinically relevant experimental model, for research aimed at improving the treatment of bone fractures accompanied by closed soft tissue injuries.

Computational simulation of the early stage of bone healing under different configurations of locking compression plates

Flexible fixation or the so-called ‘biological fixation’ has been shown to encourage the formation of fracture callus, leading to better healing outcomes. However, the nature of the relationship between the degree of mechanical stability provided by a flexible fixation and the optimal healing outcomes has not been fully understood. In this study, we have developed a validated quantitative model to predict how cells in fracture callus might respond to change in their mechanical microenvironment due to different configurations of locking compression plate (LCP) in clinical practice, particularly in the early stage of healing. The model predicts that increasing flexibility of the LCP by changing the bone–plate distance (BPD) or the plate working length (WL) could enhance interfragmentary strain in the presence of a relatively large gap size (.3 mm). Furthermore, conventional LCP normally results in asymmetric tissue development during early stage of callus formation, and the increase of BPD or WL is insufficient to alleviate this problem.

Ability of recombinant human bone morphogenetic protein 2 to enhance bone healing in the presence of tobramycin : evaluation in a rat segmental defect model

Objective To determine whether locally applied tobramycin influences the ability of recombinant human bone morphogenetic protein 2 (rhBMP-2) to heal a segmental defect in the rat femur. Methods The influence of tobramycin on the osteogenic differentiation of mesenchymal stem cells was first evaluated in vitro. For the subsequent, in vivo experiments, a 5-mm segmental defect was created in the right femur of each of 25 Sprague-Dawley rats and stabilized with an external fixator and four Kirschner wires. Rats were divided in four groups: empty control, tobramycin (11 mg)/absorbable collagen sponge, rhBMP-2 (11 μg)/absorbable collagen sponge, and rhBMP-2/absorbable collagen sponge with tobramycin. Bone healing was monitored by radiography at 3 and 8 weeks. Animals were euthanized at 8 weeks and the properties of the defect were compared with the intact contralateral femur. Bone formation in the defect region was assessed by dual-energy x-ray absorptiometry, microcomputed tomography, histology, and mechanical testing. Results Tobramycin exerted a dose-dependent inhibition of alkaline phosphatase induction and calcium deposition by mesenchymal stem cells cultured under osteogenic conditions. The inhibition was reversed in the presence of 500 ng/mL of rhBMP-2. Segmental defects in the rat femora failed to heal in the absence of rhBMP-2. Tobramycin exerted no inhibitory effects on the ability of rhBMP-2 to heal these defects and increased the bone area of the defects treated with rhBMP-2. Data obtained from all other parameters of healing, including dual-energy x-ray absorptiometry, microcomputed tomography, histology, and mechanical testing, were unaffected by tobramycin. Conclusions Although our in vitro results suggested that tobramycin inhibits the osteogenic differentiation of mesenchymal stem cells, this could be overcome by rhBMP-2. Tobramycin did not impair the ability of rhBMP-2 to heal critical-sized femoral defects in rats. Indeed, bone area was increased by nearly 20% in the rhBMP-2 group treated with tobramycin. This study shows that locally applied tobramycin can be used in conjunction with rhBMP-2 to enhance bone formation at fracture sites.

Influence of interleukin-1 beta on platelet-poor plasma clot formation: A potential impact on early bone healing

Objectives Hematoma quality (especially the fibrin matrix) plays an important role in the bone healing process. Here, we investigated the effect of interleukin-1 beta (IL-1β) on fibrin clot formation from platelet-poor plasma (PPP). Methods Five-milliliter of rat whole-blood samples were collected from the hepatic portal vein. All blood samples were firstly standardized via a thrombelastograph (TEG), blood cell count, and the measurement of fibrinogen concentration. PPP was prepared by collecting the top two-fifths of the plasma after centrifugation under 400 × g for 10min at 20°C. The effects of IL-1β cytokines on artificial fibrin clot formation from PPP solutions were determined by scanning electronic microscopy (SEM), confocal microscopy (CM), turbidity, and clot lysis assays. Results The lag time for protofibril formation was markedly shortened in the IL-1β treatment groups (243.8 ± 76.85 in the 50 pg/mL of IL-1β and 97.5 ± 19.36 in the 500 pg/mL of IL-1β) compared to the control group without IL-1β (543.8 ± 205.8). Maximal turbidity was observed in the control group. IL-1β (500 pg/mL) treatment significantly decreased fiber diameters resulting in smaller pore sizes and increased density of the fibrin clot structure formed from PPP (P < 0.05). The clot lysis assay revealed that 500 pg/mL IL-1β induced a lower susceptibility to dissolution due to the formation of thinner and denser fibers. Conclusion IL-1β can significantly influence PPP fibrin clot structure, which may affect the early bone healing process.