Abnormal and excessive accumulation of the amyloid beta-peptide (A beta) in the brain is a major and common characteristic of all Alzheimer's disease (AD) forms irrespective of their genetic background. Insoluble aggregates of A beta are identified as amyloid plaques. These deposits are thought to form when the amount of A beta is increased in the brain parenchyma as a result of either overexpression or altered processing of the amyloid precursor protein (APP). Soluble A beta ending at carboxyl-terminal residue 40 (A beta 40) and, in lesser amount, the form ending at residue 42 (A beta 42), are normal products of the APP metabolism in cell cultures. Increased secretion of soluble A beta 42 has been observed in cells transfected with constructs modeling APP gene mutations of familial forms of AD (refs 4, 5). On the basis of these in vitro data it has been hypothesized that the presence of soluble A beta 42 plays a role in the formation of amyloid plaques. Subjects affected by Down's syndrome (DS) have an increased APP gene dosage and overexpress APP. Apparently because of this overexpression, they almost invariably develop amyloid deposits after the age of 30 years, although they are free of them at earlier ages. Moreover, it has been observed that A beta 42 precedes A beta 40 in the course of amyloid deposition in DS brain. Thus, DS subjects provide the opportunity to investigate in the human brain the metabolic conditions that precede the formation of the amyloid deposits. Here we report that soluble A beta 42 is present in the brains of DS-affected subjects aged from 21 gestational weeks to 61 years but it is undetectable in age-matched controls. It is argued that overexpression of APP leads specifically to A beta 42 increase and that the presence of the soluble A beta 42 is causally related to plaque formation in DS and, likely, in AD brains.
Radial access in patients with ST-segment elevation acute coronary syndrome is associated with significant clinical benefits, in terms of both lower morbidity and cardiac mortality. Thus, it should become the recommended approach in these patients, provided adequate operator and center expertise is present. (Radial Versus Femoral Investigation in ST Elevation Acute Coronary Syndrome [RIFLE-STEACS]; NCT01420614).
To report an ataxic variant of Alzheimer disease expressing a novel molecular phenotype.Design: Description of a novel phenotype associated with a presenilin 1 mutation.
Setting:The subject was an outpatient who was diagnosed at the local referral center.Patient: A 28-year-old man presented with psychiatric symptoms and cerebellar signs, followed by cognitive dysfunction. Severe -amyloid (A) deposition was accompanied by neurofibrillary tangles and cell loss in the cerebral cortex and by Purkinje cell dendrite loss in the cerebellum. A presenilin 1 gene (PSEN1) S170F mutation was detected.
Main Outcome Measures:We analyzed the processing of A precursor protein in vitro as well as the A species in brain tissue.
Results:The PSEN1 S170F mutation induced a 3-fold increase of both secreted A 42 and A 40 species and a 60% increase of secreted A precursor protein in transfected cells. Soluble and insoluble fractions isolated from brain tissue showed a prevalence of N-terminally truncated A species ending at both residues 40 and 42.
Conclusion:These findings define a new Alzheimer disease molecular phenotype and support the concept that the phenotypic variability associated with PSEN1 mutations may be dictated by the A aggregates' composition.
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.
Our data show that multivessel, staged PCI in STEMI patients is associated with a low incidence of adverse events at follow-up but with a higher incidence of in-hospital MACE, mainly driven by periprocedural myocardial infarction during the elective procedure.
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