A biphasic scaffold design combined with cell sheet technology for simultaneous regeneration of alveolar bone/periodontal ligament complex

This study describes the design of a biphasic scaffold composed of a Fused Deposition Modeling scaffold (bone compartment) and an electrospun membrane (periodontal compartment) for periodontal regeneration. In order to achieve simultaneous alveolar bone and periodontal ligament regeneration a cell-based strategy was carried out by combining osteoblast culture in the bone compartment and placement of multiple periodontal ligament (PDL) cell sheets on the electrospun membrane. In vitro data showed that the osteoblasts formed mineralized matrix in the bone compartment after 21 days in culture and that the PDL cell sheet harvesting did not induce significant cell death. The cell-seeded biphasic scaffolds were placed onto a dentin block and implanted for 8 weeks in an athymic rat subcutaneous model. The scaffolds were analyzed by μCT, immunohistochemistry and histology. In the bone compartment, a more intense ALP staining was obtained following seeding with osteoblasts, confirming the μCT results which showed higher mineralization density for these scaffolds. A thin mineralized cementum-like tissue was deposited on the dentin surface for the scaffolds incorporating the multiple PDL cell sheets, as observed by H&E and Azan staining. These scaffolds also demonstrated better attachment onto the dentin surface compared to no attachment when no cell sheets were used. In addition, immunohistochemistry revealed the presence of CEMP1 protein at the interface with the dentine. These results demonstrated that the combination of multiple PDL cell sheets and a biphasic scaffold allows the simultaneous delivery of the cells necessary for in vivo regeneration of alveolar bone, periodontal ligament and cementum. © 2012 Elsevier Ltd.

Tracheobronchial and alveolar dose of submicrometer particles for different population age groups in Italy

Exposure to ultrafine particles (diameter less than 100 nm) is an important topic in epidemiological and toxicological studies. This study used the average particle number size distribution data obtained from our measurement survey in major micro-environments, together with the people activity pattern data obtained from the Italian Human Activity Pattern Survey to estimate the tracheobronchial and alveolar dose of submicrometer particles for different population age groups in Italy. We developed a numerical methodology based on Monte Carlo method, in order to estimate the best combination from a probabilistic point of view. More than 106 different cases were analyzed according to a purpose built sub-routine and our results showed that the daily alveolar particle number and surface area deposited for all of the age groups considered was equal to 1.5 x 1011 particles and 2.5 x 1015 m2, respectively, varying slightly for males and females living in Northern or Southern Italy. In terms of tracheobronchial deposition, the corresponding values for daily particle number and surface area for all age groups was equal to 6.5 x 1010 particles and 9.9 x 1014 m2, respectively. Overall, the highest contributions were found to come from indoor cooking (female), working time (male) and transportation (i.e. traffic derived particles) (children).

Alveolar dose comparison of ultrafine particles for Australian and Italian children

Epidemiological studies have demonstrated that exposure to particulate air pollution is associated with several adverse health effects. Recently, interest has focused on ultrafine particles (UFPs, diameter ≤ 100 nm), due to the adverse health effects caused by their ability to induce inflammation and deposit in secondary organs [1]. These effects are much more pronounced in children because they inhale a higher dose of UFPs relative to both lung size (when compared with adults) [2] and increased breathing rates, since they are generally more physically active than adults ...

Alveolar dose of ultrafine particles for children in urban environments

The aim of this study was to quantify school children’s exposure to ultrafine particles (UFP) in urban environments. The study was conducted as part of a larger epidemiological project aiming to determine the association between exposures to UFPs and children’s health, titled “Ultrafine Particles from Traffic Emissions and Children’s Health”1 (UPTECH). School children aged 8-11 years old at 24 state schools within the Brisbane Metropolitan Area participated in the present study. This paper presents the methodology and results for calculating deposited UFP surface area in the alveolar region (dose), where UFP deposition is more efficient for particles larger than 6 nm...

Identification of radiological alveolar pneumonia in children with high rates of hospitalized respiratory infections : Comparison of WHO-defined and pediatric pulmonologist diagnosis in the clinical context

Background A reliable standardized diagnosis of pneumonia in children has long been difficult to achieve. Clinical and radiological criteria have been developed by the World Health Organization (WHO), however, their generalizability to different populations is uncertain. We evaluated WHO defined chest radiograph (CXRs) confirmed alveolar pneumonia in the clinical context in Central Australian Aboriginal children, a high risk population, hospitalized with acute lower respiratory illness (ALRI). Methods CXRs in children (aged 1-60 months) hospitalized and treated with intravenous antibiotics for ALRI and enrolled in a randomized controlled trial (RCT) of Vitamin A/Zinc supplementation were matched with data collected during a population-based study of WHO-defined primary endpoint pneumonia (WHO-EPC). These CXRs were reread by a pediatric pulmonologist (PP) and classified as pneumonia-PP when alveolar changes were present. Sensitivities, specificities, positive and negative predictive values (PPV, NPV) for clinical presentations were compared between WHO-EPC and pneumonia-PP. Results Of the 147 episodes of hospitalized ALRI, WHO-EPC was significantly less commonly diagnosed in 40 (27.2%) compared to pneumonia-PP (difference 20.4%, 95% CI 9.6-31.2, P < 0.001). Clinical signs on admission were poor predictors for both pneumonia-PP and WHO-EPC; the sensitivities of clinical signs ranged from a high of 45% for tachypnea to 5% for fever + tachypnea + chest-indrawing. The PPV range was 40-20%, respectively. Higher PPVs were observed against the pediatric pulmonologist's diagnosis compared to WHO-EPC. Conclusions WHO-EPC underestimates alveolar consolidation in a clinical context. Its use in clinical practice or in research designed to inform clinical management in this population should be avoided. Pediatr Pulmonol. 2012; 47:386-392. (C) 2011 Wiley Periodicals, Inc.

Estrogen deficiency-associated bone loss in the maxilla: A methodology to quantify the changes in the maxillary intra-radicular alveolar bone in an ovariectomized rat osteoporosis model

The effects of estrogen deficiency on bone characteristics are site-dependent, with the most commonly studied sites being appendicular long bones (proximal femur and tibia) and axial bones (vertebra). The effect on the maxillary and mandibular bones is still inconsistent and requires further investigation. This study was designed to evaluate bone quality in the posterior maxilla of ovariectomized rats in order to validate this site as an appropriate model to study the effect of osteoporotic changes. Methods: Forty-eight 3-month-old female Sprague-Dawley rats were randomly divided into two groups: an ovariectomized group (OVX, n=24) and Sham-operated group (SHAM, n=24). Six rats were randomly sacrificed from both groups at time points 8, 12, 16 and 20 weeks. The samples from tibia and maxilla were collected for Micro CT and histological analysis. For the maxilla, the volume of interest (VOI) area focused on the furcation areas of the first and second molar. Trabecular bone volume fraction (BV/TV, %), trabecular thickness (Tb.Th.), trabecular number (Tb.N.), trabecular separation (Tb.Sp.), and connectivity density (Conn.Dens) were analysed after Micro CT scanning. Results: At 8 weeks the indices BV/TV, Tb.Sp, Tb.N and Conn.Dens showed significant differences (P<0.05) between the OVX and SHAM groups in the tibia. Compared with the tibia, the maxilla developed osteoporosis at a later stage, with significant changes in maxillary bone density only occurring after 12 weeks. Compared with the SHAM group, both the first and second molars of the OVX group showed significantly decreased BV/TV values from 12 weeks, and these changes were sustained through 16 and 20 weeks. For Tb.Sp, there were significant increases in bone values for the OVX group compared with the SHAM group at 12, 16 and 20 weeks. Histological changes were highly consistent with Micro CT results. Conclusion: This study established a method to quantify the changes of intra-radicular alveolar bone in the posterior maxilla in an accepted rat osteoporosis model. The degree of the osteoporotic changes to trabecular bone architecture is site-dependent and at least 3 months are required for the osteoporotic effects to be apparent in the posterior maxilla following rat OVX.

Estimation of red blood cell lifespan from alveolar carbon monoxide measurements

Measurement of alveolar carbon monoxide (CO) presents a facile technique to estimate the lifespan, L, of red blood cells (RBCs) in vivo. Several recent studies employ this technique and calculate L (in days) using the expression, L = 13.8 (Hb)/P-CO(end), where (Hb) is the concentration (in g/dL) of hemoglobin in blood, and P-CO(end) is the endogenous production of CO (in ppm). Implicit in this calculation is the assumption that the fraction, f, of endogenous CO production due to RBC turnover is a constant equal to 0.7, which yields the expected RBC lifespan, L approximate to 120 days, in normal controls. In anemic patients, however, enhanced RBC turnover may increase f substantially above 0.7. The above expression then overestimates L. Here, we deriv an alternative tive expression, L = 3390[Hb]/322P(CO (end)-110, that accounts explicitly for the dependence of f on the rate of RBC turnover and thereby provides more accurate estimates of L without requiring additional measurements. Using the latter expression, we recalculate L from recent measurements on hepatitis C virus infected patients undergoing treatment with ribavirin. We find that our estimates of L in these patients (39 +/- 13 days) are significantly lower than current estimates (46 +/- 14 days), indicating that ribavirin affects RBC survival more severely than expected from current studies. Our expression for L is simple to employ in a clinical setting and would render the broadly applicable technique of alveolar CO measurement for the estimation of RBC lifespan more accurate.

Pulsatile blood flow in a rigid pulmonary alveolar sheet with porous walls

This paper deals with the pulsatile blood flow in the lung alveolar sheets by idealizing each of them as a channel covered by porous media. As the blood flow in the lung is of low Reynolds number, a creeping flow is assumed in the channel. The analytical and numerical results for the velocity and pressure distribution in the porous medium are presented. The effect of an imposed slip condition is also studied. Comparisons with the corresponding results for the steady-state case are made at the end.

Human alveolar T lymphocyte responses to Mycobacterium tuberculosis antigens: role for CD4+ and CD8+ cytotoxic T cells and relative resistance of alveolar macrophages to lysis.

T cell-mediated cytotoxicity against Mycobacterium tuberculosis (MTB)-infected macrophages may be a major mechanism of specific host defense, but little is known about such activities in the lung. Thus, the capacity of alveolar lymphocyte MTB-specific cell lines (AL) and alveolar macrophages (AM) from tuberculin skin test-positive healthy subjects to serve as CTL and target cells, respectively, in response to MTB (H37Ra) or purified protein derivative (PPD) was investigated. Mycobacterial Ag-pulsed AM were targets of blood CTL activity at E:T ratios of > or = 30:1 (51Cr release assay), but were significantly more resistant to cytotoxicity than autologous blood monocytes. PPD- plus IL-2-expanded AL and blood lymphocytes were cytotoxic for autologous mycobacterium-stimulated monocytes at E:T ratios of > or = 10:1. The CTL activity of lymphocytes expanded with PPD was predominantly class II MHC restricted, whereas the CTL activity of lymphocytes expanded with PPD plus IL-2 was both class I and class II MHC restricted. Both CD4+ and CD8+ T cells were enriched in BL and AL expanded with PPD and IL-2, and both subsets had mycobacterium-specific CTL activity. Such novel cytotoxic responses by CD4+ and CD8+ T cells may be a major mechanism of defense against MTB at the site of disease activity.

Alveolar macrophages as accessory cells for human gamma delta T cells activated by Mycobacterium tuberculosis.

Alveolar macrophages form the first line of defense against inhaled droplets containing Mycobacterium tuberculosis by controlling mycobacterial growth and regulating T cell responses. CD4+ and gamma delta T cells, two major T cell subsets activated by M. tuberculosis, require accessory cells for activation. However, the ability of alveolar macrophages to function as accessory cells for T cell activation remains controversial. We sought to determine the ability of alveolar macrophages to serve as accessory cells for resting (HLA-DR-, IL-2R-) and activated (HLA-DR+, IL-2R+) gamma delta T cells in response to M. tuberculosis and its Ag, and to compare accessory cell function for gamma delta T cells of alveolar macrophages and blood monocytes obtained from the same donor. Alveolar macrophages were found to serve as accessory cells for both resting and activated gamma delta T cells in response to M. tuberculosis Ag. At high alveolar macrophage to T cell ratios (> 3:1), however, expansion of resting gamma delta T cells was inhibited by alveolar macrophages. The inhibition of resting gamma delta T cells by alveolar macrophages was dose-dependent, required their presence during the first 24 h, and was partially overcome by IL-2. Alveolar macrophages did not inhibit activated gamma delta T cells even at high accessory cell to T cell ratios, and alveolar macrophages functioned as well as monocytes as accessory cells. Monocytes were not inhibitory for either resting or activated gamma delta T cells. These findings support the following model. In the normal alveolus the alveolar macrophage to T cell ratio is > or = 9:1, and therefore the threshold for resting gamma delta T cell activation is likely to be high. Once a nonspecific inflammatory response occurs, such as after invasion by M. tuberculosis, this ratio is altered, favoring gamma delta T cell activation by alveolar macrophages.

Estudo quantitativo da matriz extracelular e células do músculo liso de bexigas urinária após traumatismo raquimedular

Lesões na inervação do trato urinário inferior ocasionado por traumatismo raquimedular afetam geralmente o músculo detrusor e o esfíncteres uretrais. Estas alterações acarretam problemas basicamente de incontinência urinária e aumento da pressão intravesical, decorrente deste traumatismo, trazendo consequências para o funcionamento do sistema urinário superior. Quantificar os elementos fibrosos da matriz extracelular e fibras musculares das bexigas neurogênicas hiper-reflexas comparando-as com bexigas normais. Foram utilizadas 6 amostras de bexigas neurogênicas de indivíduos que foram submetidos a cirurgia de reparação por cistoenteroplastia realizados pelo serviço de urologia do Hospital Municipal Souza Aguiar, estas amostras foram fixadas imediatamente em solução tamponada de formalina a 10%. O controle com amostras iguais as do estudo extraída de cadáveres cuja causa morte não relacionava-se ao sistema urogenital macroscópicamente. O material foi submetido as seguintes técnicas histoquímicas: H&E, van Gieson e Resorcina Fucsina resorcina de Weigert com prévia oxidação pela oxona. Imunohistoquímica: anti-elastina. A observação dos cortes corados pelo van Gieson demonstrou uma diminuição significativa do músculo liso de 13% e aumento do colágeno em 72% e as fibras do sistema elástico um aumento de 101%. Conclusão. Nas bexigas neurogênicas hiper-reflexas o músculo detrusor e os elementos fibrosos da matriz foram profundamente modificados. As fibras do sistema elástico foram as mais afetadas.

Incidencia y factores asociados a la hemorragia intracraneal en pacientes con traumatismo craneoencefálico leve

198 p.

Alveolar nitric oxide and its role in pediatric asthma control assessment

Resumen Background: Nitric oxide can be measured at multiple flow rates to determine proximal (maximum airway nitric oxide flux; Jaw(NO)) and distal inflammation (alveolar nitric oxide concentration; CA(NO)). The main aim was to study the association among symptoms, lung function, proximal (maximum airway nitric oxide flux) and distal (alveolar nitric oxide concentration) airway inflammation in asthmatic children treated and not treated with inhaled glucocorticoids. Methods: A cross-sectional study with prospective data collection was carried out in a consecutive sample of girls and boys aged between 6 and 16 years with a medical diagnosis of asthma. Maximum airway nitric oxide flux and alveolar nitric oxide concentration were calculated according to the two-compartment model. In asthmatic patients, the asthma control questionnaire (CAN) was completed and forced spirometry was performed. In controls, differences between the sexes in alveolar nitric oxide concentration and maximum airway nitric oxide flux and their correlation with height were studied. The correlation among the fraction of exhaled NO at 50 ml/s (FENO50), CA(NO), Jaw(NO), forced expiratory volume in 1 second (FEV1) and the CAN questionnaire was measured and the degree of agreement regarding asthma control assessment was studied using Cohen's kappa. Results: We studied 162 children; 49 healthy (group 1), 23 asthmatic participants without treatment (group 2) and 80 asthmatic patients treated with inhaled corticosteroids (group 3). CA(NO) (ppb) was 2.2 (0.1-4.5), 3 (0.2-9.2) and 2.45 (0.1-24), respectively. Jaw(NO) (pl/s) was 516 (98.3-1470), 2356.67 (120-6110) and 1426 (156-11805), respectively. There was a strong association (r = 0.97) between FENO50 and Jaw(NO) and the degree of agreement was very good in group 2 and was good in group 3. There was no agreement or only slight agreement between the measures used to monitor asthma control (FEV1, CAN questionnaire, CA(NO) and Jaw(NO)). Conclusions: The results for CA(NO) and Jaw(NO) in controls were similar to those found in other reports. There was no agreement or only slight agreement among the three measure instruments analyzed to assess asthma control. In our sample, no additional information was provided by CA(NO) and Jaw(NO).

A influência da espessura óssea na medição da altura da borda alveolar em imagens de tomografia computadorizada de feixe cônico e espiral

Imagens de tomografia computadorizada (TC) permitem a visualização, sem distorções ou sobreposições, do complexo maxilo-facial, principalmente do osso alveolar. Estudos demonstraram boa reprodutibilidade e precisão da mensuração da altura da borda alveolar, todavia a influência da espessura óssea ainda é pouco descrita. Através da comparação com a mensuração direta, o objetivo deste estudo foi avaliar a precisão, reprodutibilidade e a influência da espessura óssea, na mensuração da altura da borda alveolar em imagens volumétricas e imagens bidimensionais multiplanares em TC de feixe cônico (TCFC) e em TC espiral (TCE). Utilizando 10 mandíbulas secas de humanos, 57 dentes anteriores foram tomografados em equipamentos iCAT (Imaging Science International, Hatfield, PA, EUA) e Brilliance 64 canais (Philips Eletronics, Eindhoven, Holanda), ambos utilizando voxels de 0,25 mm. Através de imagens volumétricas (3D) e imagens bidimensionais (2D) de cortes multiplanares, foi comparada a mensuração da altura da borda alveolar dessas imagens com a mensuração direta nas mandíbulas, feita por vestibular e lingual, por três avaliadores, com o auxílio de um paquímetro, totalizando 114 bordas alveolares medidas. Alta reprodutibilidade intra-avaliador (0,999 a 0,902) e interavaliador (0,998 e 0,868) foi observada através do índice de correlação intraclasse (ICC). Observou-se alta correlação entre a mensuração direta e indireta da altura da borda alveolar em imagens 2D, sendo r=0,923** e 0,916**, e em imagens 3D, com r=0,929** e 0,954*, em TCFC e TCE, respectivamente. Imagens 2D superestimam a altura da borda alveolar em 0,32 e 0,49 mm e imagens 3D em 0,34 e 0,30 mm, em TCFC e TCE respectivamente. Quando o osso alveolar apresenta espessura de no mínimo 0,6 mm a média da diferença entre medidas diretas e indiretas é de 0,16 e 0,28 mm em imagens 2D e de 0,12 e 0,03 mm em imagens 3D para TCFC e TCE respectivamente, sendo que 95% do limite de concordância varia de -0,46 a 0,79 mm e -0,32 a 0,88 mm em imagens 2D, e de -0,64 a 0,67 mm e -0,57 a 0,62 mm em imagens 3D, para TCFC e TCE respectivamente. Quando o osso alveolar é mais fino do que 0,6 mm a TC é imprecisa, pois 95% do limite de concordância variou de -1,74 a 5,42 mm e -1,64 a 5,42 mm em imagens 2D, e de -3,70 a 4,28 mm e -3,49 a 4,25 mm em imagens 3D, para TCFC e TCE respectivamente. Conclui-se que a mensuração da altura da borda alveolar através de imagens tomográficas apresenta alta reprodutibilidade, sendo que quando a borda alveolar apresenta pelo menos 0,6 mm, a precisão da mensuração é alta, todavia quando esta espessura é menor do que 0,6 mm a técnica é imprecisa.