TURBULENT BOUNDARY-LAYER AND THE EFFECT OF CRITICAL ROUGHNESS REYNOLDS-NUMBERS ON THE RECOVERY LENGTH BEHIND AN ISOLATED SPHERICAL ROUGHNESS ELEMENT UNDER VARIABLE PRESSURE-GRADIENT

The transition characteristics and the boundary layer development behind an isolated spherical roughness element were investigated in an open-circuit, suction-type wind tunnel. The experiments were performed upon a smooth aluminiuim flat plate placed in the test section of the tunnel. The desired pressure gradient was obtained by means a false roof placed in the test section. In this article, emphasis is given to the recovery length of the turbulent boundary layer behind an isolated spherical roughness element under zero, favorable, and adverse pressure gradienst. The recovery length of the turbulent boundary layer is correlated with the critical roughness Reynolds number REkce and Rekcs

Coexistence of acute myocardial infarction with normal coronary arteries and migraine with aura in a female patient

Acute myocardial infarction with normal coronary arteries is a well known condition, which is typically diagnosed in young patients. Coronary vasospasm, inherited, acquired or malignancy-induced hypercoagulable state, collagen vascular disease and coronary arterial embolism have been considered as underlying etiologic factors. An association between migraine with aura and increased risk of ischemic stroke, angina and myocardial infarction has been demonstrated in studies. Patients with migraine and especially with aura should be followed closely against cardiovascular events even if they are young and do not have traditional risk factors

Artykuł oryginalnyStężenie asymetrycznej dwumetyloargininy u chorych z tętniakami tętnic wieńcowych

Background: Endothelial dysfunction might be one of the pathophysiological mechanisms in the development of coronary artery ectasia (CAE) although the exact mechanisms have not yet been demonstrated. Asymmetric dimethylarginine (ADMA), an endogenous competitive inhibitor of nitric oxide synthase, is also related to endothelial and structural dysfunction. Aim: To asses the relationship between CAE and ADMA plasma concentrations. Methods: Thirty patients with CAE in a mean age of 55.5 &#177; 3.6 years and 40 patients with normal coronary arteries in a mean age of 53.3 &#177; 11.6 years were studied. The ADMA levels of all patients were analysed by ELISA method. Results: The mean ADMA level in the CAE group was found to be significantly higher than the mean ADMA level in the normal coronary artery group (2.26 &#177; 0.47 vs. 1.43 &#177; 0.40 &#181;mol/l, p 1.80 &#181;mol/l) was present in 83.0% of patients from the CAE group and 25.0% of patients from the normal coronary artery group (p < 0.001). Having an increased ADMA level enhanced the risk of CAE 15-fold. The multiple-adjusted OR of the risk of CAE was 18.71 (95% CI 4.95-70.68) for the higher ADMA level compared to the lower level. Conclusion: Asymmetric dimethylarginine level is significantly associated with the presence of coronary artery ectasia. These findings suggest that increased ADMA level may be associated with endothelial dysfunction leading to the development of coronary artery ectasia.Wstęp: Zaburzenia funkcji śródbłonka mogą leżeć u podłoża powstawania tętniaków tętnic wieńcowych, choć dokładny mechanizm tego zjawiska nie został dotąd poznany. Asymetryczna dwumetyloarginina (ADMA), endogenny inhibitor syntazy tlenku azotu, jest związana z dysfunkcją śródbłonka. Cel: Ocena stężenia ADMA u chorych z tętniakami tętnic wieńcowych i bez nich. Metody: Do badania włączono 30 chorych (25 mężczyzn, wiek 55,5 &#177; 3,6 roku) z tętniakami tętnic wieńcowych. Grupę kontrolną stanowiło 40 osób (32 mężczyzn, wiek 53,3 &#177; 11,6 roku) z prawidłowymi tętnicami wieńcowymi. Stężenie ADMA badano przy użyciu testu ELISA. Wyniki: Stężenie ADMA było statystycznie istotnie wyższe w grupie badanej niż w grupie kontrolnej (odpowiednio: 2,26 &#177; 0,47 vs 1,43 &#177; 0,40 mmol/l, p 1,80 mmol/l) stwierdzono u 83% chorych w grupie badanej i 25% osób w grupie kontrolnej. Wnioski: Stężenie ADMA jest podwyższone u chorych z tętniakami tętnic wieńcowych. Wskazuje to na możliwość istnienia związku tak określonej dysfunkcji śródbłonka z powstawaniem tętniaków tętnic wieńcowych