Tracheal cryopreservation: caspase-3 immunoreactivity in tracheal epithelium and in mixed glands

Cryopreservation has an immunomodulating effect on tracheal tissue as a result of class II antigen depletion due to epithelium exfoliation. However, not all epithelium is detached. We evaluated the role of apoptosis in the remaining epithelium of 30 cryopreserved tracheal grafts. Caspase-3 immunoreactivity of tracheal epithelium was studied in canine tracheal segments cryopreserved with F12K medium, with or without subsequent storage in liquid nitrogen at -196°C for 15 days. Loss of structural integrity of tracheal mixed glands was observed in all cryopreserved tracheal segments. Caspase-3 immunoreactivity in tracheal mucosa and in mixed glands was significantly decreased, in contrast to the control group and to cryopreserved tracheal segments in which it remained high, due to the effect of storage in liquid nitrogen (P < 0.05, ANOVA and Tukey test). We conclude that apoptosis can be triggered in epithelial cells during tracheal graft harvesting even prior to cryopreservation, and although the epithelial caspase-3 immunoreactivity is reduced in tracheal cryopreservation, this could be explained by increased cell death. Apoptosis cannot be stopped during tracheal cryopreservation

Prevalence of chronic obstructive pulmonary disease in asymptomatic smokers

Ra&uacute;l H Sansores, M&oacute;nica Vel&aacute;zquez-Uncal, Oliver P&eacute;rez-Bautista, Jaime Villalba-Caloca, Ramc&eacute;s Falf&aacute;n-Valencia, Alejandra Ram&iacute;rez-VenegasTobacco Smoking and COPD Research Department, National Institute of Respiratory Diseases, Ismael Cosio Villegas, Mexico City, MexicoBackground: Physicians do not routinely recommend smokers to undergo spirometry unless they are symptomatic.Objective: To test the hypothesis that there are a significant number of asymptomatic smokers with chronic obstructive pulmonary disease (COPD), we estimated the prevalence of COPD in a group of asymptomatic smokers.Methods: Two thousand nine hundred and sixty-one smokers with a cumulative consumption history of at least 10 pack-years, either smokers with symptoms or smokers without symptoms (WOS) were invited to perform a spirometry and complete a symptom questionnaire.Results: Six hundred and thirty-seven (21.5%) smokers had no symptoms, whereas 2,324 (78.5%) had at least one symptom. The prevalence of COPD in subjects WOS was 1.5% when considering the whole group of smokers (45/2,961) and 7% when considering only the group WOS (45/637). From 329 smokers with COPD, 13.7% were WOS. Subjects WOS were younger, had better lung function and lower cumulative consumption of cigarettes, estimated as both cigarettes per day and pack-years. According to severity of airflow limitation, 69% vs 87% of subjects were classified as Global Initiative for Chronic Obstructive Lung Disease stages&nbsp;I&ndash;II in the WOS and smokers with symptoms groups, respectively (P&lt;0.001). A multivariate analysis showed that forced expiratory volume in 1 second (mL) was the only predictive factor for COPD in asymptomatic smokers.Conclusion: Prevalence of COPD in asymptomatic smokers is 1.5%. This number of asymptomatic smokers may be excluded from the benefit of an &ldquo;early&rdquo; intervention, not just pharmacological but also from smoking cessation counseling. The higher forced expiratory volume in 1 second may contribute to prevent early diagnosis.Keywords: COPD, asymptomatic smokers, early diagnosi

Cryopreserved tracheal segments: a new tool for bench surgical training in thoracic surgery Segmentos criopreservados de traqueia: uma nova ferramenta para auxiliar o treinamento na cirurgia torácica

PURPOSE: To present a new low-cost high fidelity bench model of cryopreserved trachea that can be used to learn surgical skills from medical students to cardiothoracic surgery fellows. METHODS: Ten tracheas were harvested from ten non-trachea related research dogs at the moment of euthanasia. Each trachea was trimmed in six or seven rings segments. They were cryopreserved and stored during 60 days. The day programmed for surgical skills practice, they were thawed to room temperature. RESULTS: Forty segments have been used. After defrosting, all the segments kept their normal anatomic shape and structural integrity. Two incisions were made on every tracheal segment and sutured with running or separate stitches with 5-0 polypropilene. There were no complications such as cartilage ruptures, neither tears on the mucosae, the cartilages nor the membranous posterior membrane. CONCLUSIONS: The cryopreserved trachea is a high fidelity, practical, reproducible, portable, low-cost bench model. It allows cardiothoracic fellows to learn how to handle a trachea, as well as to perfect their surgical and suture abilities before applying them on a real patient's trachea.<br>OBJETIVO: Apresentar novo modelo de traquéia criopreservada de baixo custo e alta fidelidade que pode ser usado tanto por estudantes de medicina como por cirurgiões cardiotorácicos no aprendizado e desenvolvimento de suas habilidades cirúrgicas. MÉTODOS: Foram coletados amostras de dez traquéias de dez cães utilizados para pesquisa após a eutanásia. Cada segmento de traquéia foi dividida em seis ou sete anéis, criopreservadas e armazenadas durante 60 dias. No dia programado para a prática cirúrgica os segmentos foram descongelados a temperatura ambiente. RESULTADOS: Foram utilizados 40 segmentos no estudo. Após o descongelamento todos os segmentos mantiveram sua forma anatômica e sua integridade estrutural. Foram realizadas duas incisões em cada segmento traqueal que foram suturadas em padrão continuo ou com pontos separados utilizando sutura de polipropileno 5-0. Não houve nenhuma complicação como a ruptura da cartilagem, rasgos na mucosa, cartilagem ou na membrana membranosa posterior. CONCLUSÕES: O modelo de traquéia criopreservada é altamente fidedigno, prático, reproduzível, portátil e de baixo custo. Permite que os cirurgiões cardiotorácicos aprendam como manipular a traquéia, assim como aperfeiçoar suas habilidades cirúrgicas antes de sua aplicação em traquéias de pacientes reais

Lyophilized glutaraldehyde-preserved bovine pericardium for experimental atrial septal defect closure

A variety of patch materials has been used to close large atrial septal defects (ASD). Autologous pericardium and glutaraldehyde-preserved bovine pericardium are the most used. Lyophilized bovine pericardium has not been tested inside the cardiovascular system. The aim of this work was to study the behaviour and effectiveness of lyophilized glutaraldehyde-preserved bovine pericardium in ASD closure. Sixteen mongrel dogs were operated on. A 3 cm diameter atrial septal defect was created, and closed with: Group I (n=8): Lyophilized glutaraldehyde preserved bovine pericardium (LGPBP). Group II (n=8): Vascular Dacron patch. The animals were evaluated clinically, by echocardiography, macroscopically, and microscopically. Statistical analysis was done with analysis of variance (ANOVA) and Student’s t-test. All the animals survived the surgical procedure and study time (6 months). Clinically all the animals displayed normal physical activity, with normal cardiac sounds. Echocardiography showed that both groups had a normal heart without intracardiac shunts, no thrombus formation, and no vegetations. Macroscopically all the animals showed good integration of the lyophilized bioprosthesis and Dacron patch. All group I animals presented a decrease of the area of the ASD in the left atrium (p<0.001 by ANOVA and Student’s t-test). Microscopically, group I presented dense and well-organized collagenous tissue, areas of cartilaginous metaplasia and remnants of the lyophilized bioprosthesis (p<0.001 by ANOVA and Student’s t-test). Group II showed encapsulated Dacron patch covered with collagenous tissue and cartilaginous metaplasia. In conclusion, the new lyophilized bioprosthesis is well integrated into the atrial septum, without complications and is effective for ASD closure