Regulation of proline biosynthesis and resistance to drought stress in two barley (Hordeum vulgare L.) genotypes of different origin.

Drought is considered the main abiotic stress factor that inhibits growth of crop plants (including barley), limiting yield in many regions worldwide. Predicted climate changes show that in future the frequency and intensity of drought events will rise, so crops that are resistant to this stress are in demand. One of the adaptive metabolic responses to drought is the accumulation of proline. The aim of this study was to examine the effect of 10-day drought on tissue dehydration and proline biosynthesis in leaves as well as in roots of barley genotypes of different origin: the Syrian breeding line Cam/B1/CI and the German cultivar Maresi. The involvement of Δ1 pyrroline-5-carboxylate synthetase (P5CS), the expression of the P5CS gene and ABA in proline synthesis under drought were also studied. Finally, we examined the resistance of tested genotypes to applied drought using chlorophyll fluorescence parameters and above-ground dry matter accumulation. Drought caused a gradual decrease of water content and an increase of proline and ABA content in roots and leaves of both genotypes. A statistically significant positive correlation between proline accumulation and activity of P5CS was also revealed. The skyrocketing increase of P5CS activity and proline accumulation was proceeded by transcriptional up-regulation of P5CS. The relationships between changes in P5CS expression, P5CS activity and ABA content show that the latter compound is involved in drought-induced proline synthesis at the transcription and enzyme activity level. The examined barley genotypes were equally resistant to applied moderate drought stress regardless of the differences in the level of proline accumulated.

Separate and combined responses to water deficit and UV-B radiation.

Crops and other plants in natural conditions are routinely affected by several stresses acting simultaneously or in sequence. In areas affected by drought, plants may also be exposed to enhanced UV-B radiation (280-315nm). Each of these stress factors differently affects cellular metabolism. A common consequence of plant exposure to the separate action of water deficit and UV-B radiation is the enhanced generation of reactive oxygen species (ROS) causing damage to proteins, lipids, carbohydrates and DNA. Despite this destructive activity, ROS also act as signalling molecules in cellular processes responsible for defence responses. Plants have evolved many physiological and biochemical mechanisms that avoid or tolerate the effects of stress factors. Water deficit avoidance leads to stomatal closure, stimulation of root growth, and accumulation of free proline and other osmolytes. Secondary metabolites (flavonols, flavones and anthocyanins) that accumulate in epidermal cells effectively screen UV-B irradiation and reduce its penetration to mesophyll tissue. The coordinated increased activity of the enzymatic antioxidant defence system such as up-regulation of superoxide dismutase, catalase, guaiacol peroxidase, ascorbate peroxidase and glutathione reductase is an important mechanism of tolerance to water deficit and UV-B radiation. The accumulation of low molecular antioxidants (proline, glycine betaine, ascorbate and glutathione) can also contribute to tolerance to water deficit. Polyamines, tocopherol, carotenoids, alkaloids, flavonoids and other secondary metabolites participate in the removal of ROS under conditions of increased UV-B radiation. The combination of water deficit and UV-B radiation induces responses that can be antagonistic, additive or synergistic in comparison with the action of single stresses. UV-B radiation may enhance resistance to water deficit and vice versa. Hydrogen peroxide, nitric oxide (NO), abscisic acid (ABA), jasmonic acid, ethylene, and salicylic acid participate in the activation of defence mechanisms. The involvement of these molecules in cross-resistance may rely on activation of enzymatic and non-enzymatic antioxidant systems, enzymes of flavonoid biosynthesis and the accumulation of low-molecular-weight osmolytes as well as regulation of stomatal closure. However, under the conditions of prolonged action of stressors or in the case where one of them is severe, the capacity of the defence system becomes exhausted, leading to damage and even death.

[A case of recurrent stent thrombosis in a drug-eluting stent following antiplateled therapy discontinuation]. / Nawracajaca zakrzepica w stencie powlekanym po odstawieniu leków przeciwplytkowych.

Stent thrombosis is one of the major complications that occur in percutaneous coronary interventions with stents. Various factors have been attributed to the development of stent thrombosis and several strategies have been recommended for its management. We report a case of 45 year-old patient with recurrent subacute and late stent thrombosis following antiplateled therapy discontinuation on the 6th day and 11th month after he discharging from hospital.

[Recurrent ventricular tachycardia as a late complication of a cardiac stab wound]. / Nawracajace czestoskurcze komorowe jako pózne powiklanie rany klutej serca.

We present a case of a 55-year-old male who suffered from a cardiac stab wound in his youth and 38 years later developed unstable sustained ventricular tachycardia. Imaging showed presence of a scarf of myocardium which probably caused the arrhythmia. Arrhythmia was successfully controlled using combined treatment with pharmacotherapy and cardioverter-defibrillator implantation. Relapses of ventricular tachycardia treated by appropriate interventions of cardioverter-defibrillator occurred when the patient stopped pharmacotherapy and experienced great psychic stress.

Clinical manifestations of slow coronary flow from acute coronary syndrome to serious arrhythmias.

Slow coronary flow is an angiographic phenomenon characterized by delayed opacification of vessels in the absence of any evidence of obstructive epicardial coronary disease. In this article, we present serious clinical manifestations of extremely slow coronary flow in two hypertensive patients with preserved ejection fraction in echocardiographical examination: a 57 year-old woman with acute coronary syndrome and temporary ST elevation; and a 65 year-old man with atrial tachycardia which was leading to sudden arrest of circulation. The woman was admitted to hospital due to recurrent syncope and chest pain. Because of severe bradycardia, an AAI pacemaker was implanted. Coronary angiography without evident obstructive lesion revealed extremely slow flow of dye through arteries. The man was admitted to hospital because of heart palpitations (paroxysmal atrial tachycardia, PAT) followed by chest pain. During hospitalization, a sudden arrest of circulation in the course of supraventricular tachycardia of 220/min with atrioventricular conduction of 1:1 occurred. Coronary arteriography did not show any occlusions in the coronary arteries, although extremely slow dye flow was seen. Electrophysiological examination revealed arrhythmia of the left atrial (PAT) (tricuspid valve anulus mapping) without induced ventricular arrhythmia. Because of symptomatic bradyarrhythmia, a VVI heart pacemaker was implanted. Over a 12-month observation, his heart rate remained under control, and the patient did not complain of chest pains or heart palpitations.

Myocarditis - clinical course and 2-year outcome in 32 patients.

BACKGROUND: Acute myocarditis is one of the most challenging diagnoses in cardiology. It is a disease with variable clinical presentation, progression and outcome. AIM: To assess clinical characteristics and outcome of patients hospitalised with diagnosis of acute myocarditis from year 2006 to 2008. METHODS: We analysed hospital files of consecutive 32 patients admitted to our hospital due to myocarditis. All demographic, clinical and laboratory data were analysed and compared between patients with acute or subacute myocarditis. After discharge the patients were followed for 8-24 months. RESULTS: The majority of patients were males (84%) in a mean age of 33 years. Clinical and echocardiographic parameters improved in 25 (78%) of patients during hospital stay. During follow-up decreased left ventricular ejection fraction (LVEF) was observed more often in patients with subacute than acute myocarditis (mean LVEF values of 49 vs. 61%, respectively). Patients with a subacute form of the disease more frequently required chronic pharmacological therapy and more often retired from occupational activities. CONCLUSIONS: Diagnosis of myocarditis is still challenging. Careful history taking, serial laboratory, ECG and echocardiographic examinations are helpful in therapeutic decisions making and assessing prognosis. Patient with subacute myocarditis are more symptomatic than patients with acute myocarditis.

[Acute myocardial infarction during pregnancy complicated with pulmonary oedema]. / Zawal serca w ciazy powiklany obrzekiem pluc.

Acute myocardial infarction, a rare peripartum event, is accompanied by significant maternal and fetal mortality. We report a 41-year-old woman who developed an acute myocardial infarction during the third trimester of pregnancy. The case of infarction was complicated with pulmonary oedema on the 3 day after delivery. Coronary angiography was performed 7 weeks post partum and no coronary lesions were detected. Therapeutic options in such condition are discussed and review of relevant literature is presented.