Sleep study in patients with overweight and obesity.

Obstructive sleep apnea syndrome (OSAS) is a disorder characterized by repetitive collapse of the pharyngeal airway during sleep, which leads to oxygen desaturation, sleep fragmentation and daytime somnolence. Obesity is one of the most important risk factor for the development of OSAS. The exact mechanisms responsible for the relationship between obesity and OSAS are still unclear. The fat deposits in the pharynx region as well as the reduction in the lung volume have been considered as factors that might be responsible for the increase of the upper airway collapsibility. The aim of our study was to evaluate the correlation between the Body Mass Index (BMI) and sleep study parameters in overweight and obese patients suffering from breathing disturbances during sleep. We studied a group of 106 consecutive obese or overweight patients with a primary complaint of snoring or other breathing disturbances during sleep. In all cases, BMI and sleep studies (PolyMESAM) were examined. We evaluated relationship between the BMI and sleep study parameters such as Respiratory Disturbance Index (RDI), Apnea Index (AI), Desaturation Index (DI) and Average of Lowest Saturation (LSAT). The results showed the lack of significant statistical correlations between BMI and all the sleep parameters studied in the overweight patients and the statistical positive correlation between the BMI and RDI in the obese cases. We conclude that BMI determination may be considered as a simple, yet important predictor, of the OSAS in the group of obese patients.

A new recombinant thrombolytic and antithrombotic agent with higher fibrin affinity--a staphylokinase variant. I. In vitro study.

We attempted to construct a new recombinant protein characterized by fibrin-specific properties of plasminogen activation combined with antithrombin and antiplatelet activities. To the C-terminal part of recombinant staphylokinase (r-SAK), which is a promising profibrinolytic agent, we assembled: (i) the Kringle 2 domain (K2) of tissue-type plasminogen activator (t-PA), containing a fibrin-specific binding site, (ii) the RGD sequence (Arg-Gly-Asp) for the prevention of platelet aggregation and (iii) the antithrombotic agent - hirudin. The cDNA for hybrid protein SAK-RGD-K2-Hir was cloned into pESP-3 yeast protein expression vector. The introduction of K2 t-PA, RGD sequence and hirudin into r-SAK molecule did not alter the SAK activity. The plasminogen activation rate (determined by K(M) and K(cat)) of SAK-RGD-K2-Hir was not significantly different from that of r-SAK. Affinity and binding strength of the recombinant protein to fibrin immobilized on the biosensor were higher than to r-SAK. We observed a higher clot lysis potency of SAK-RGD-K2-Hir as evidenced by a faster and more profound lysis of 125I-labeled human fibrin clots. The potency of thrombin inhibition by the hirudin part of the recombinant fusion protein SAK-RGD-K2-Hir was the same as that of r-Hir alone. In conclusion, the results of the in vitro study suggest that the SAK-RGD-K2-Hir construct can be a more potent and faster-acting thrombolytic agent with antithrombin and antiplatelet properties compared with standard r-SAK.