One-third of the world's population is infected with Mycobacterium tuberculosis (M.tb), which causes tuberculosis. Mycobacterium tuberculosis cell envelope components such as glycolipids, lipoglycans and polysaccharides play important roles in bacteria-host cell interactions that dictate the host immune response. However, little is known about the changes in the amounts and types of these cell envelope components as the bacillus divides during in vitro culture. To shed light on these phenomena, we examined growth-dependent changes over time in major cell envelope components of virulent M.tb by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, thin-layer chromatography, mass spectrometry, immunoblotting and flow cytometry. Our studies provide evidence that major mannosylated glycoconjugates on the M.tb cell envelope change as M.tb grows in vitro on the widely used Middlebrook 7H11 agar. In particular, our compositional analyses show that from Day 9 to 28 the amounts of mannose-containing molecules, such as mannose-capped lipoarabinomannan, lipomannan and phosphatidyl-myo-inositol mannosides, change continuously in both the cell envelope and outer cell surface. Along with these changes, mannan levels on the outer cell surface also increase significantly over time. The implications of these differences in terms of how M.tb is grown for studies performed in vitro and in vivo for assessing M.tb-host recognition and establishment of infection are discussed.
Background: Tracheobronchial stents are often used to manage lung transplant airway complications. In 2005, the Food and Drug Administration (FDA) issued a warning against the use of metallic stents for benign airway disease. Since that time, fully covered hybrid metallic stents have been developed and are increasingly used due to their ease of insertion and removal. There is limited data to support their safe utilization for transplant airway complications. This is the largest analysis to date of the safety of hybrid metallic stents for transplant airway complications. Methods:We performed a retrospective study of patients who had covered metallic stents placed for transplant airway complications between April 2016 to April 2021. Information obtained from chart review included demographics, procedure notes and stent data including indication for placement, type, size, location, duration, and complications. Results:We identified 50 patients who had a combined 376 stents placed for a total of 15,711 stent days. The most common minor complication and reason for removal was mucus plugging affecting 193 stents.There were only two cases of major stent associated complications. Among minor complications, there was a increased risk of stent fracture with Bonastent ® (P=0.04). Conclusions:Our data shows that hybrid metallic stents are a safe intervention for patients with transplant airway complications. Most complications were minor and managed with repeat bronchoscopy. There were only two major complications over a 5-year period. Given the wide spectrum of possible airway complications, further research is needed to determine the optimal use of stents for patients with transplant airway complications.
IntroductionLung cancer is a major challenge facing modern medicine. It is the leading cause of cancer-related death in the USA. Little is known of the incidence, prevalence and disease characteristics in lung transplant recipients, a population unique in its vulnerability and exposure to carcinogenic risk factors. We aimed to elaborate these characteristics of lung cancer in our population through a retrospective cohort study.MethodsWe retrospectively reviewed our institution’s 8-year experience with lung transplantation and searched for patients with a post-transplant diagnosis of lung cancer, neoplasia or mass. We focused on patient demographics, indication for transplant, smoking history, stage at diagnosis, location of the tumour, length of time between transplant and diagnosis, the treatment offered and length of time from diagnosis to death or last follow-up. Descriptive statistics and survival analysis standard Kaplan-Meier method was conducted from the date of cancer diagnosis to death from all-cause mortality or last follow-up as of August 2021.ResultsWe identified 24 patients with de novo lung cancer postlung transplant in 905 recipients. More patients with an underlying diagnosis of idiopathic pulmonary fibrosis developed lung cancer. Twenty-one patients were diagnosed with non-small cell lung cancer and three had small cell lung cancer. The remaining native lung was involved most in single lung recipients with 17 patients. Patients with a diagnosis of lung cancer had a mean survival of 17.6 months after diagnosis.DiscussionThe incidence rate of lung cancer in our cohort was higher than reported for smokers from the general population in previous studies. In this study, we compare our findings with available literature. We also explore screening strategies, treatment modalities, survival and postulated mechanisms for the development of lung cancer in lung transplant recipients.
Introduction Acute respiratory distress syndrome (ARDS) is present in approximately 10% of ICU admissions and is associated with great morbidity and mortality. Prone ventilation has been shown to improve refractory hypoxemia and mortality in patients with ARDS. Methods In this simulation, a 70-year-old male had been transferred to the ICU for ARDS and was undergoing scheduled prone ventilation as part of his care when he experienced a cardiopulmonary arrest secondary to a tension pneumothorax. Learners demonstrated how to manage cardiac arrest in a prone patient and subsequently identified and treated the tension pneumothorax that was the cause of his initial arrest. This single-session simulation for internal medicine residents (PGY 1-PGY 4) utilized a prone mannequin connected to a ventilator in a high-fidelity simulation center. Following the simulation, facilitators led a team debriefing and reviewed key learning objectives. Results A total of 103 internal medicine residents participated in this simulation. Of those, 43 responded to a postsimulation survey. Forty-two of 43 agreed or strongly agreed that all learning objectives were met, that the simulation was appropriate for their level of training, and that their participation would be useful for their future practice. Discussion We designed this simulation to improve learners' familiarity with prone cardiopulmonary resuscitation and to enhance overall comfort with cardiac arrest management. Postsimulation survey results and debriefings revealed that the simulation was a valuable education opportunity, and learners felt that their participation in this simulation would be helpful in their future practice.
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