AddressesBackground The first step in the evaluation of patients with pleural effusion is to determine whether the effusion is a transudate or an exudate. Osteopontin (OPN) is a pleiotropic integrin-binding protein with many functions. We assessed pleural effusion and serum concentrations of OPN and C-reactive protein (CRP) in patients with different types of pleural effusions.

Chronic Obstructive Pulmonary Disease (COPD) is increasingly recognized as a systemic disease characterized by progressive airflow limitation as well as respiratory and peripheral muscle weakness. Deficiency in the levels of carnitine "an essential nutrient for optimal muscle function" has been associated with peripheral and respiratory muscle weakness in other diseases, but has not yet been examined in COPD patients. The aim of this study was to investigate whether plasma acyl carnitine fractions were reduced in patients with COPD, and examine if the deficiency correlated with COPD severity. Patients and methods:A prospective case control study to compare acyl carnitine levels and other parameters in 81 COPD patients treated at the Pulmonology Department, King Fahad Specialist Hospital Dammam, with 48 age and sex matched healthy controls. All subjects participating in the study underwent a complete physical examination and detailed pulmonary function tests (PFTs). Blood samples were taken for acyl carnitine profiles as well as a panel of other tests including albumin, total protein, Iron, CRP and pre-albumin. Acyl carnitine profile was determined using LC-MS/MS analysis.Results: COPD patients had significantly lower total carnitine levels compared to controls (43.9±6.5 and 22.7±11.9 respectively). Furthermore there was a significantly greater reduction in carnitine levels in patients with very severe COPD compared to patients with mild COPD. Conclusion:Our study demonstrated a significant deficiency in carnitine levels in COPD patients, and the degree of deficiency correlated with the severity of COPD.