Acute Respiratory Distress Syndrome: A Clinical Update:

Superoxide Anion, the Main Species of ROS in the Development of ARDS Induced by Oleic Acid

It is believed that reactive oxygen species (ROS) play a very important role in the pathogenesis of acute respiratory distress syndrome (ARDS), but the mechanism has not been so clear, owing to the absence of direct measurable (experimental) data. In majority of the medical studies on free radicals, the analysis of ROS has generally been done by the way of measuring their secondary and breakdown products. In our study, we used electron spin resonance (ESR), a sensitive and accurate technique to detect ROS directly and also used some other sensitive techniques including ultra-weak luminescence and chemical luminescence to identify the species and relative amount of ROS. Furthermore, superoxide dismutase (SOD) was pre-administrated in ARDS rats to verify the results from the above studies and explore the possibility of the clinical application of SOD in ARDS. The spectra of ESR showed that the concentration of ROS increased at 10 min and reached a summit at 30 min after injection of oleic acid (OA), then dropped gradually. The scavenging effects of different scavenging agents on ROS by the analysis of ultra-weak luminescence proved that superoxide anion was the main species of ROS in the development of OA-induced ARDS. Moreover, the results of quantified measure of superoxide anion by chemical luminescence also showed the accordant tendency exhibited in ESR measurement. The pre-treatment of SOD might distinctly inhibit the production of superoxide anion, obviously improve the blood gas status, lung wet/dry ratio and lung/body ratio in ARDS rats. It is suggested that ROS may play a key role in the initiation phase of ARDS, while superoxide anion may be a leading actor in this process and SOD could effectively protect rats from ARDS. These results may provide helpful information for the treatment and prevention of ARDS.

The yield and safety of thoracentesis in hematopoietic stem cell transplantation recipients

The aim of this study was to assess the diagnostic value and safety of thoracentesis in hematopoietic stem cell transplantation (HSCT) recipients. We identified all hospitalized HSCT recipients who underwent thoracentesis from 1998 to 2006. We collected patients' clinical characteristics, indications for thoracenstesis, the complications of the procedure, and the etiology of the pleural effusion. A total of 50 thoracentesis findings were analyzed. Twenty-six patients underwent allogeneic HSCT, while 24 patients underwent autologous HSCT. The main indications for performing thoracentesis were to rule out infection and document or diagnose malignancy. Pleural effusions were characterized as exudate in 33 patients (66%). A specific diagnosis based on the thoracentesis was made in 13 patients (26%). These were malignancy in nine patients, parapneumonic in three patients, and empyema in one patient. The only documented complication was pneumothorax in five patients. The presence of exudative effusion and underlying solid malignancy were associated with specific diagnosis by thoracentesis (p = 0.0001 and 0.013, respectively). In spite of the tendency of HSCT recipients to develop pulmonary infections, complex parapneumonic effusions are rarely diagnosed by thoracentesis. The rate of complications is comparable to other patient populations.

Failure to eradicate AIDS-associated primary effusion lymphoma with high-dose chemotherapy and autologous stem cell reinfusion: case report and literature review

Primary effusion lymphoma (PEL), also known as body cavity-based lymphoma, is a newly recognized AIDS-related malignancy that is etiopathologically linked to Kaposi's sarcoma (KS)-associated human herpes virus type 8 (HHV-8). PEL is characterized by presentation in serous body cavities without identifiable tumor masses. Tumor cells have high-grade morphologic features, an indeterminate immunophenotype, B-lineage genotype, and contain HHV-8 and often Epstein-Barr virus. PEL rarely responds to systemic chemotherapy. Herein, we describe what we believe is the first patient with AIDS-associated PEL to be treated with high-dose chemotherapy and autologous stem cell reinfusion. Treatment was well tolerated but the patient succumbed to progressive cancer. Our experience with this patient serves to underscore the high mortality rate associated with this unique neoplasm.