Effects of platelet-rich fibrin produced by three centrifugation protocols on bone neoformation in defects created in rat calvaria.

This study evaluated the potential of Leukocyte-platelet-rich fibrin (L-PRF; fixed angle centrifugation protocol), Advanced-platelet-rich fibrin (A-PRF; low-speed fixed angle centrifugation protocol), and Horizontal-platelet-rich fibrin (H-PRF; horizontal centrifugation protocol) in bone neoformation in critical size defects (CSDs) in rat calvaria. Thirty-two rats were divided into groups: Control (C), L-PRF, A-PRF, and H-PRF. 5 mm diameter CSDs were created in the animals' calvaria. Defects from group Control (C) were filled with blood clots, while defects from groups L-PRF, A-PRF, and H-PRF were filled with respective platelet-rich fibrin (PRF) membranes. L-PRF, A-PRF, and H-PRF were prepared from animal blood collection and specific centrifugation protocols. At 14 and 30 days, calcein (CA) and alizarin (AL) injections were performed, respectively. Animals were euthanized at 35 days. Microtomographic, laser confocal microscopy, and histomorphometric analyzes were performed. Data were statistically analyzed (ANOVA, Tukey, p < .05). L-PRF, A-PRF, and H-PRF groups showed higher values of bone volume (BV), newly formed bone area (NFBA), and precipitation of CA and AL than the C group (p < .05). The H-PRF group showed higher values of BV, number of trabeculae (Tb. N), NFBA, and higher precipitation of AL than the A-PRF and L-PRF groups (p < .05). Therefore, it can be concluded that: i) L-PRF, A-PRF, and H-PRF potentiate bone neoformation in CSDs in rat calvaria; ii) H-PRF demonstrated more biological potential for bone healing

Effects of platelet aggregates produced by three centrifugation protocols on bone neoformation in defects created in rat calvaria

Este estudo avaliou o potencial regenerativo de agregados plaquetários obtidos por 3 protocolos diferentes produzidos em equipamentos de centrifugação horizontal (H-PRF) e de ângulo fixo (L-PRF e A-PRF) na neoformação óssea em defeitos de tamanho crítico (DTCs) em calvária de ratos. Previamente à execução do experimento principal, animais adicionais foram utilizados para validação dos protocolos de centrifugação utilizados neste estudo por meio de análise por pipetagem sequencial. Para o experimento principal, 32 ratos foram divididos em quatro grupos: C, L-PRF, A-PRF e H-PRF. Após coleta de sangue dos animais por punção cardíaca, agregados plaquetários foram preparados por protocolos de centrifugação vertical (L-PRF e A-PRF, preparados em centrífuga de ângulo fixo [33° de angulação do rotor, 55mm de raio na altura do coágulo, 86mm de raio máximo]) e horizontal (H-PRF, preparado em centrífuga de rotor basculante). Para o preparo da L-PRF, o sangue foi centrifugado a uma Força Centrífuga Relativa máxima (RCFmax) de 701g (Força G) por 12 minutos; para o preparo da A-PRF, o sangue foi centrifugado a uma RCFmax de 216g, por 14 minutos; o preparo da H-PRF foi realizado pela centrifugação do sangue a uma RCFmax de 700g por 8 minutos. Foram criados DTCs de 5mm de diâmetro nas calvárias dos animais por osteotomia com broca trefina em baixa rotação e irrigação abundante com solução salina estéril. Marcações de amálgama foram feitas para auxiliar a identificação das margens originais do defeito durante o processamento laboratorial. Os defeitos dos grupos C, L-PRF, A-PRF e H-PRF foram preenchidos com coágulo sanguíneo, L-PRF, A-PRF e H-PRF, respectivamente. Aos 14 e 30 dias foram realizadas injeções dos fluorocromos calceína (CA) e alizarina (AL), respectivamente. A eutanásia ocorreu aos 35 dias pós-operatórios. Análises microtomográficas, por microscopia de fluorescência e histomorfométricas foram realizadas. Os dados foram estatisticamente analisados (ANOVA, Tukey, p<0,05). Os grupos L-PRF, A-PRF e H-PRF apresentaram maiores valores de volume ósseo percentual (BV/TV), área de osso neoformado (AON) e maior precipitação de CA e AL do que o grupo C (p<0.05). O grupo H-PRF apresentou maiores valores de BV/TV, número de trabéculas ósseas (Tb.N), AON e maior precipitação de AL do que os grupos A-PRF e L-PRF (p<0,05). Pode-se concluir que: i) os agregados plaquetários L-PRF, A-PRF e H-PRF potencializam a neoformação óssea em DTCs em calvária de ratos; ii) o protocolo de centrifugação horizontal promoveu maior neoformação óssea no tratamento de DTCs criados em calvária de ratos.This study evaluated the regenerative potential of platelet aggregates obtained by 3 different protocols produced in horizontal (H-PRF) and fixed-angle (L-PRF and A-PRF) centrifuge in bone neoformation in critical size defects (CSDs) in rat calvaria. Prior to the execution of the main experiment, additional animals were used to validate the centrifugation protocols used in this study by sequential pipetting analysis. For the main experiment, 32 rats were divided into four groups: C, L-PRF, A-PRF and H-PRF. After collecting blood from the animals by cardiac puncture, platelet aggregates were prepared by vertical centrifugation protocols (L-PRF and A-PRF, prepared in a fixed-angle centrifuge [33° rotor angle, 55mm radius at the clot height, 86mm maximum radius]) and horizontal (H-PRF, prepared in a swing-out rotor centrifuge). To prepare the L-PRF, the blood was centrifuged at a Relative Centrifugal Force (RCF)-max of 701g (G-force) for 12 minutes; to prepare the A-PRF, the blood was centrifuged at 216g RCFmax for 14 minutes; H-PRF preparation was performed by centrifuging the blood at 700g RCFmax for 8 minutes. 5mm diameter DTCs were created in the animals\' calvaria by osteotomy with a trephine drill at low rotation and abundant irrigation with sterile saline solution. Amalgam markings were made to help identify the original margins of the defect during laboratory processing. Defects in groups C, L-PRF, A-PRF and H-PRF were filled with blood clot, L-PRF, A-PRF and H-PRF, respectively. At 14 and 30 days, injections of the fluorochromes calcein (CA) and alizarin (AL) were performed, respectively. Euthanasia took place 35 days after surgery. Microtomographic, fluorescence microscopy and histomorphometric analyzes were performed. Data were statistically analyzed (ANOVA, Tukey, p<0.05). The L-PRF, A-PRF and H-PRF groups showed higher values of percent bone volume (BV/TV), newly formed bone area (NFBA) and greater precipitation of CA and AL than the C group (p<0.05). The H-PRF group showed higher values of BV/TV, number of trabeculae (Tb.N), NFBA and higher precipitation of AL than the A-PRF and L-PRF groups (p<0.05). It can be concluded that: i) platelet aggregates L-PRF, A-PRF and H-PRF potentiate bone neoformation in DTCs in rat calvaria; ii) the horizontal centrifugation protocol promoted greater bone neoformation in the treatment of CSDs created in rat calvaria

Epidemiology of TB in prisoners: a metanalysis of the prevalence of active and latent TB

Abstract Background Tuberculosis (TB) in prisons usually occurs at higher rates than in the general population, especially in developing countries. TB has been reported as the most common cause of death among prisoners. Studies have shown limitations for early detection of TB in prisons that seem to result from mistaken concepts about TB, delayed diagnosis mainly due to the naturalization of lack of healthcare for this population Methods A scoping review was performed using the methodology of the Joanna Briggs Institute to assess “What are the scientific evidences on the epidemiology of TB in the prison system?”. Then, a meta-analysis was performed to assess the prevalence of TB (active and latent) TB in prisoners. The results are presented as prevalence, in percentage, through random effects models, with a confidence interval of 95%. Results Regarding active TB, the results of the metanalysis showed that countries with a high burden of TB had a prevalence of 3.54% [2.71; 4.63], countries not considered to be high burden TB countries had a prevalence of 1.43% [0.86; 2.37]. Latent TB had a prevalence of 51.61% [39.46; 63.58] in high TB burden countries and a prevalence of 40.24% [23.51; 59.61] in countries with low TB burden. In terms of development, in low- and lower-middle-income countries, the prevalence of active TB was 3.13% [1.84; 5.29] and in high- and upper-middle income countries the prevalence was 2.25% [1.70; 2.99]. The prevalence of latent TB in high- and middle-income countries was 43.77% [28.61; 60.18] and of 49.42% [45.91; 52.94] in low and lower middle-income countries. Conclusion Our analysis suggests that TB, and probably other infectious diseases, find fertile ground in prisons where previous acquire social disadvantages seem to thrive—therefore, TB in prisons is a global public health problem and effective strategies are needed to control the disease are needed targeting the prison environment, including rapid health assessments to understand each context and to implement tailored and precision interventions

Comparison of the effects of platelet concentrates produced by high and low-speed centrifugation protocols on the healing of critical-size defects in rat calvaria: a microtomographic and histomorphometric study.

The current study evaluated the healing of critical-size defects (CSD) created in rat calvaria treated with platelet concentrates produced by high-speed (Leukocyte- and Platelet-Rich Fibrin - L-PRF) and low-speed (Advanced Platelet-Rich Fibrin - A-PRF) protocols of centrifugation. Twenty-four rats were distributed into three groups: Control, L-PRF, and A-PRF. Five mm diameter CSD were created on the animals' calvaria. The defects of the L-PRF and A-PRF groups were filled with 0.01 ml of L-PRF and A-PRF, respectively. The control group defects were filled with a blood clot only. All animals were euthanized on the 35th postoperative day. Histomorphometric and microtomographic analyses were then performed. The L-PRF and A-PRF groups had significantly higher bone volume and neoformed bone area than those of the control group and lowered bone porosity values (p < .05). No significant differences were observed between A-PRF and L-PRF groups for the analyzed parameters. Therefore, it can be concluded that i) L-PRF and A-PRF potentiated the healing of CSD in rat calvaria; ii) high and low-speed centrifugation protocols did not produce PRF matrices with different biological impacts on the amount of bone neoformation