Epicardial cysts: report of two rare cases

Epicardial cysts originating directly from the epicardium are seen very rarely. Complete surgical excision is recommended when these cysts are detected. If cysts compress surrounding vital structures, cardiopulmonary bypass (CPB) should also be considered. We report herein 2 cases of multiloculated epicardial cysts, both of which were successfully excised, 1 with CPB.     

Efficient coupling of catalysis and dynamics in the E1 component of Escherichia coli pyruvate dehydrogenase multienzyme complex

Protein motions are ubiquitous and are intrinsically coupled to catalysis. Their specific roles, however, remain largely elusive. Dynamic loops at the active center of the E1 component of Escherichia coli pyruvate dehydrogenase multienzyme complex are essential for several catalytic functions starting from a predecarboxylation event and culminating in transfer of the acetyl moiety to the E2 component. Monitoring the kinetics of E1 and its loop variants at various solution viscosities, we show that the rate of a chemical step is modulated by loop dynamics. A cysteine-free E1 construct was site-specifically labeled on the inner loop (residues 401-413), and the EPR nitroxide label revealed ligand-induced conformational dynamics of the loop and a slow "open <--> close" conformational equilibrium in the unliganded state. An (19)F NMR label placed at the same residue revealed motion on the millisecond-second time scale and suggested a quantitative correlation of E1 catalysis and loop dynamics for the 200,000-Da protein. Thermodynamic studies revealed that these motions may promote covalent addition of substrate to the enzyme-bound thiamin diphosphate by reducing the free energy of activation. Furthermore, the global dynamics of E1 presumably regulate and streamline the catalytic steps of the overall complex by inducing an entirely entropic (nonmechanical) negative cooperativity with respect to substrate binding at higher temperatures. Our results are consistent with, and reinforce the hypothesis of, coupling of catalysis and regulation with enzyme dynamics and suggest the mechanism by which it is achieved in a key branchpoint enzyme in sugar metabolism.     

Does vitamin C or its combination with vitamin E improve radial artery endothelium-dependent vasodilatation in patients awaiting coronary artery bypass surgery?

Background

We evaluated the vasodilatory effects of two antioxidants, vitamins C (ascorbic acid) and E (α-tocopherol), on radial artery and endothelium-dependent responses in patients awaiting coronary artery bypass surgery.

Methods

The study was performed in three groups. The first group took 2 g of vitamin C orally (n = 31, vitamin C group), the second group took 2 g of vitamin C with 600 mg of vitamin E orally (n = 31, vitamins C + E group), and the third group took no medication (n = 31, control group). After baseline measurements were taken of the radial artery lumen diameter, flow volume and lumen area in the non-dominant radial artery, occlusion was maintained for five minutes with a pressure cuff placed around the arm. The measurements were taken again at the time of deflating the cuff, and 60 seconds later. The measurements were repeated after medication in two of the groups and after placebo in the third group.

Results

We compared values of the vitamin C group with those of the vitamins C + E group, and found that the latter were higher than those of the vitamin C group but not statistically significant. In the control group, there was no statistical difference.

Conclusion

Vitamin C or its combination with vitamin E significantly enhanced endothelium-dependent vasodilatation in the radial circulation of patients with coronary artery disease. Its combination with vitamin E was superior to vitamin C administration alone for endothelial enhancement but this difference was not statistically significant. We hypothesised that vitamin C or its combination with vitamin E may be used as antioxidants for arterial graft patency in patients undergoing coronary artery surgery.     

Effects of cortisol suppression on sleep-associated consolidation of neutral and emotional memory.

BACKGROUND: Previous research indicates that hippocampus-dependent declarative memory benefits from early nocturnal sleep, when slow-wave sleep (SWS) prevails and cortisol release is minimal, whereas amygdala-dependent emotional memory is enhanced through late sleep, when rapid eye movement (REM) sleep predominates. The role of the strong cortisol rise accompanying late sleep for emotional memory consolidation has not yet been investigated. METHODS: Effects of the cortisol synthesis inhibitor metyrapone on sleep-associated consolidation of memory for neutral and emotional texts were investigated in a randomized, double-blind, placebo-controlled study in 14 healthy men. Learning took place immediately before treatment, which was followed by 8 hours of sleep. Retrieval was tested at 11 am the next morning. RESULTS: Metyrapone suppressed cortisol during sleep and blocked particularly the late-night rise in cortisol. It reduced SWS and concomitantly impaired the consolidation of neutral texts. Emotional texts were spared from this impairing influence, however. Metyrapone even amplified emotional enhancement in text recall indicating amygdala-dependent memory. CONCLUSIONS: Cortisol blockade during sleep impairs hippocampus-dependent declarative memory formation but enhances amygdala-dependent emotional memory formation. The natural cortisol rise during late sleep may thus protect from overshooting emotional memory formation, a mechanism possibly pertinent to the development of posttraumatic stress disorder.     

Primary ocular adnexal mucosa-associated lymphoid tissue lymphoma (MALT): single institution experience in a large cohort of patients

Extranodal marginal zone B-cell lymphoma is the most common orbital tumour. We conducted a retrospective analysis to examine: (i) the impact of initial presentation and staging on outcome and (ii) response to various treatment modalities and the effect of the latter on recurrence. Ninety patients with primary ocular adnexal marginal zone lymphoma (POAML) diagnosed at our institution between 1984 and 2009 were studied. POAML was associated with monoclonal gammopathy (13%) at presentation. Most POAML patients (86%) presented with Ann-Arbor stage I disease. Radiotherapy led to excellent local control, but relapses occurred in 18% of Ann-Arbor stage I patients during a median follow-up of 5 years. Local relapses, including secondary central nervous system (CNS) involvement, were observed in patients receiving radiation doses <30·6 Gy. No differences in relapse rate and survival were observed between patients who did or did not undergo staging bone marrow biopsy. Ann-Arbor stage II-IV disease and high lactate dehydrogenase levels were associated with shorter freedom from progression. In conclusion, POAML is an indolent lymphoma with continuous risk for relapse. Radiation doses of at least 30·6 Gy should be given in Ann-Arbor stage I disease, since lower doses may be more frequently associated with relapses, including CNS relapses.