In most cases, surgery of aortic dissections repairs only the ascending portion of the aorta, leaving a residual dissection in the arch and descending aorta. We studied 17 patients operated upon for ...type A aortic dissection. A total of 42 magnetic resonance imaging (MRI) examinations were performed, with two to five studies per patient (mean 2.47). The studies were done between 5 weeks and 47 months (mean 17.5 months) after surgery. The patients were evaluated by MRI using gated spin-echo and gradient-echo sequences on axial and oblique sagittal views, and in selected cases, coronal views. A high incidence of abnormalities was observed. Pericardial hematoma was observed in 11% of cases, aortic and branch involvement in 41%, abdominal aortic branch involvement in 47%, dilatation of native aorta in 58%, and extension of dissection in 10%. New complications were detected during follow-up in 53% of patients. MRI was helpful in the follow-up of patients operated upon for aortic dissections, owing to its noninvasiveness and multiplanarity. By means of this technique, it was possible to obtain information about the natural history of the disease, as well as information useful for subsequent treatment.
In diabetic patients, the pathophysiologic mechanisms of exercise‐induced left ventricular (LV) dysfunction remain controversial. In this study, the role of myocardial contractility recruitment in ...determining an abnormal LV response to isometric or dynamic exercise has been investigated in 14 diabetic patients with autonomic dysfunction. Ischemic heat disease was excluded by the absence of LV wall motion abnormalities induced by isotonic and isometric exercise and by coronary angiography. Left ventricular and myocardial function were studied at rest, and during isometric and isotonic exercise, by two‐dimensional echocardiography; moreover, recruitment of an inotropic reserve was assessed by postextra‐systolic potentiation at rest and at peak handgrip. An abnormal response of LV ejection fraction to isometric (9/14) or to dynamic (8/14) exercise was frequent in study patients. In these patients, baseline myocardial contractility was normal, and the significant increase in ejection fraction by postextrasystolic potentiation indicated a normal contractile reserve (65 ± 7% vs. 74 ± 6%, p=0.001). Nevertheless, the downward displacement of LV ejection fraction‐systolic wall stress relationships during exercise suggests an inadequate increase in myocardial contractility. However, the abnormal ejection fraction at peak handgrip was completely reversed by postextrasystolic potentiation (67 ± 6% vs. 58.1 ± 10%, p=0.008), a potent inotropic stimulation independent of the integrity of adrenergic cardiac receptors. A defective inotropic recruitment, despite the presence of a normal LV contractile reserve, plays an important role in deexercise LV dysfunction in diabetic patients with autonomic neuropathy.
We studied the lymphocyte subpopulations in 14 pregnant women with type 1 insulin-dependent diabetes mellitus (IDDM), mean age (+/- SD) 30 +/- 4 years, mean disease duration 12 +/- 5 years, in 14 ...with gestational diabetes mellitus (GDM) (mean age 33 +/- 6 years) and 21 matched healthy pregnant controls (C), when the subjects delivered, and in their newborn. The GDM and IDDM mothers show a significant increase (p < 0.05) of lymphocytes in comparison with C (GDM 1.83 +/- 0.5 x 10(9)/l, IDDM 1.6 +/- 0.68 x 10(9)/l, C 1.06 +/- 0.45 x 10(9)/l lymphocytes), which has repercussion on lymphocyte subpopulations absolute values. The newborn of GDM mothers have an increase of lymphocytes T-activated (0.6 +/- 0.3 vs 0.3 +/- 0.2%; p < 0.05) and a reduction of NK lymphocytes than C (8.9 +/- 9 vs 15.5 +/- 7.6%; p < 0.05). The newborn of IDDM mothers show a significant reduction of NK lymphocytes than C (10 +/- 6 vs 15.5 +/- 7.6%; p < 0.05). So in newborn of diabetic mothers there is a deficit of natural immunity at birth which has to be evaluated by follow-up study.
We present a deformed star-product for a particle in the presence of a magnetic monopole. The product is obtained within a self-dual quantization-dequantization scheme, with the correspondence ...between classical observables and operators defined with the help of a quaternionic Hilbert space, following work by Emch and Jadczyk. The resulting product is well defined for a large class of complex functions and reproduces (at first order in hbar) the Poisson structure of the particle in the monopole field. The product is associative only for quantized monopole charges, thus incorporating Dirac's quantization requirement.
We describe a programme to quantize a particle in the field of a (three dimensional) magnetic monopole using a Weyl system. We propose using the mapping of position and momenta as operators on a ...quaternionic Hilbert module following the work of Emch and Jadczyk.
MicroRNAs are key, recently discovered, regulators of gene expression. They are involved in many physiological cellular pathways so it is not surprising that an altered microRNA expression pattern ...can be involved in the pathogenesis of many disease states. The possibility to manipulate microRNAs to obtain a therapeutical effect is very attractive since they represent specific targets in a particular cellular pathway and because it is quite easy to synthesize short oligonucleotides with the ability to interfere with microRNA mechanism of action. The main problem for microRNA-based therapy is represented by delivery. In the last two years many studies have underlined the involvement of microRNAs in many aspects of ischemic heart disease, the leading cause of morbidity and mortality in the Western World. MiR-29 is involved in fibrotic reaction after myocardial infarction while miR-21 may exert a fundamental role in post-angioplasty restenosis. MiR-208 is involved in the shift toward a fetal gene expression pattern in contractile proteins in heart failure. MiR-1 influences susceptibility to cardiac arrhythmias after myocardial infarction. This review will focus on microRNAs involvement in multiple aspects of ischemic heart disease and on their promising novel therapeutic applications including some recent patents.
PDF
