Presence and content of kynurenic acid in animal feed.

Kynurenic acid (KYNA) was found to be an antagonist of iontropic glutamate receptors and alpha7 nicotinic acetylcholine receptors. Furthermore, it was documented that KYNA is an agonist of G-protein coupled GPR35 receptors which are mainly present in the gastrointestinal tract. It was also found that KYNA is present in the gastrointestinal tract and that its concentration gradually increases along it. The origin of KYNA in the gastrointestinal tract is not known. Both might be synthesized from tryptophan in it or absorbed from food and other dietary products. Therefore, the aim of the study was to investigate the concentration of KYNA in animal feed. The results indicate that the highest concentration of KYNA was found in animal feeds intended for livestock. The lower amount of KYNA was detected in animal feeds for fish. Interestingly, the lowest amount of KYNA was found in dog and cat feeds. Furthermore, an analysis of KYNA content in animal food ingredients was conducted. The concentration of KYNA found in one of the ingredients ­ rapeseed meal ­ was several times higher in comparison to animal feeds studied. The content of KYNA in the remaining feed ingredients tested was significantly lower. This is the first report on the concentration of KYNA in animal feeds. There is a need for further detailed analysis leading to establishing a set of guidelines for animal feeding.

Microvolt T-wave alternans predicts cardiac events after acute myocardial infarction in patients treated with primary percutaneous coronary intervention.

BACKGROUND: Current risk stratification after acute myocardial infarction (MI) depends on left ventricular ejection fraction. Microvolt T-wave alternans (MTWA) is one of promising markers to predict cardiac events in patients after acute MI treated according to current guidelines. METHODS: In this single center study, 112 consecutive patients with the first anterior ST-elevation MI undergoing PCI <12 hours from symptom onset, were enrolled prospectively. Demographics, established risk factors, myocardial contrast echocardiography (MCE) perfusion, index event data and MTWA were assessed. Composite cardiac events (CCE) defined as: death, recurrent MI, sustained ventricular tachycardia (sVT) or readmission for acute heart failure (HF) were recorded during follow-up. RESULTS: MTWA test was negative in 76, positive in 18 and undetermined in 7 patients. MTWA negative patients had significantly higher LVEF at 30 days. At 4 years, 26 patients experienced CCE (10 died, 2 reinfarcted and 14 HF events). In multivariate Cox proportional hazard model maximum CKMB, non-negative MTWA and reduced LVEF made the best model to predict CCE. Four year CCE free survival was 77% and was significantly lower for non-negative MTWA (94% vs 50%, p<0.003). CONCLUSIONS: Non-negative MTWA with infarct size index and reduced LVEF could predict cardiac events in patients with anterior STEMI treated with primary PCI. MTWA non-negative patients have significantly worse outcome.

Morphological aspects of the aortofemoral graft thrombosis.

Sixty seven patients underwent aorto-femoral double velour grafting for aortoiliac occlusive disease and 38 patients were treated for recurrent lower limb ischemia following aortofemoral grafting. Apart from various clinical examinations the patients underwent angiography as well as the morphological investigation of specimens obtained from abdominal aortae, common femoral arteries and from grafts implanted into the aorto-femoral section. The examinations showed that diffuse intimal thickening may, in the course of atherosclerosis, convert itself into uncomplicated fibrous and further into complicated plaques impairing mainly graft outflow. The drawbacks of grafts are: 1) persistens of fibrin deposits on the luminal surface of the prosthesis which may contribute to thrombosis development, 2) appearance of foci or bands of hyalinized connective tissue causing the stiffening of the graft, 3) development of lesions resembling atheromatous changes at the anastomotic areas and, 4) anastomotic hyperplasia which may contribute to stenosis at the femoral implantation site.

Morphological changes in femoropopliteal venous grafts.

Morphological examination of specimens obtained from 82 venous grafts implanted into the femoropopliteal section were done. Intimal oedema, necrosis of single smooth muscle cells and partial exfoliation of the endothelium with as occurrence of parietal thrombi may lead to early graft impatency. The late cause of stenosed inner diameter below 4 mm in the venous graft was in 14,6% the hyperplasia of the smooth muscle cells and collagen and elastin fibres in the intima, whereas in 4,9% the changes were defined as graft atherosclerosis.