1,087 research outputs found
Chronic hyponatremia in a patient with renal salt wasting and without cerebral disease: relationship between RSW, risk of fractures and cognitive impairment
Renal salt wasting syndrome (RSW) is defined as a renal loss of sodium leading to hyponatremia and a decrease in extracellular fluid volume (ECV). Differentiation of this disorder from the syndrome of inappropriate antidiuretic hormone secretion (SIADH), a common cause of hyponatremia, can be difficult because both can present with hyponatremia and concentrated urine with natriuresis. Our clinical case about a 78-year-old woman with a recent fracture of the right femur not only confirms that this syndrome can occur in patients without intracranial pathologies (CT documented), but depicts how the hyponatremia caused by RSW can show a chronic, oscillating course. This is an interesting point of view because it suggests to us to consider RSW in the differential diagnosis of patients with chronic hyponatremia
Detection, characterization and sizing of hydrogen induced cracking in pressure vessels using phased array ultrasonic data processing
Pressure vessels operating in sour service conditions in refinery environments can be subject to the risk of H₂S cracking resulting from the hydrogen entering into the material. This risk, which is related to the specific working conditions and to the quality of the steel used, shall be properly managed in order to maintain the highest safety at a cost-effective level. Nowadays the typical management strategy is based on a risk based inspection (RBI) evaluation to define the inspection plan used in conjunction with a fitness for service (FFS) approach in defining if the vessel, although presenting dangerous defects such as cracks, can still be considered “fit for purpose” for a given time window based on specific fracture mechanics analysis. These vessels are periodically subject to non-destructive evaluation, typically ultrasonic testing. Phased Array (PA) ultrasonic is the latest technology more and more used for this type of application. This paper presents the design and development of an optimized Phased Array ultrasonic inspection technique for the detection and sizing of hydrogen induced cracking (HIC) type flaws used as reference for comparison. Materials used, containing natural operational defects, were inspected in “as-service” conditions. Samples have then been inspected by means of a “full matrix capture” (FMC) acquisition process followed by “total focusing method” (TFM) data post processing. FCM-TFM data have been further post-processed and then used to create a 3D geometrical reconstruction of the volume inspected. Results obtained show the significant improvement that FMC/TFM has over traditional PA inspection techniques both in terms of sensitivity and resolution for this specific type of defect. Moreover, since the FMC allows for the complete time domain signal to be captured from every element of a linear array probe, the full set of data is available for post-processing. Finally, the possibility to reconstruct the geometry of the component from the scans, including the defects present in its volume, represents the ideal solution for a reliable data transferring process to the engineering function for the subsequent FFS analysi
Np95 Is Implicated in Pericentromeric Heterochromatin Replication and in Major Satellite Silencing
Heterochromatin plays an important role in transcriptional repression, for the correct segregation of chromosomes and in the maintenance of genome stability. Pericentric heterochromatin (PH) replication and formation have been proposed to occur in the pericentric heterochromatin duplication body (pHDB). A central question is how the underacetylated state of heterochromatic histone H4 tail is established and controlled, because it is a key event during PH replication and is essential to maintain the compacted and silenced state of these regions. Np95 is a cell cycle regulated and is a nuclear histone-binding protein that also recruits HDAC-1 to target promoters. It is essential for S phase and for embryonic formation and is implicated in chromosome stability. Here we show that Np95 is part of the pHDB, and its functional ablation causes a strong reduction in PH replication. Depletion of Np95 also causes a hyperacetylation of lysines 8, 12, and 16 of heterochromatin histone H4 and an increase of pericentromeric major satellite transcription, whose RNAs are key players for heterochromatin formation. We propose that Np95 is a new relevant protein involved in heterochromatin replication and formation
Anderson-Fabry disease: a multiorgan disease.
Fabry disease (FD) is a rare X-linked lysosomal storage disorder caused by a deficiency of the enzyme α-galactosidase A . FD causes glycolipids, such as globotriaosylceramide (Gb3), to accumulate in the vascular endothelium of several organs (fig.2), including the skin, kidneys, nervous system, and heart, thereby triggering inflammation and fibrosis . These processes generally result in organ dysfunction, which is usually the first clinical evidence of FD. Patients with classic FD have various symptoms, eg, acroparesthesias, hypohidrosis, angiokeratomas, corneal opacities, cerebrovascular lesions, cardiac disorders, andrenal dysfunction.However, evolving knowledge about the natural course of disease suggests that it is more appropriate to describe FD as a disease with a wide spectrum of heterogeneously progressive clinical phenotypes. Indeed, most female heterozygotes develop symptoms due to yet undetermined mechanisms and a high percentage of females develops vital organ involvement including the kidneys, heart and/or brain about a decade later than males . Renal failure is a serious complication of this disease. Fabry nephropathy lesions are present and progress in childhood while the disease commonly remains silent by routine clinical measures. Early and timely diagnosis of Fabry nephropathy is crucial since late initiation of enzyme replacement therapy may not halt progressive renal dysfunction. This may be challenging due to difficulties in diagnosis of Fabry disease in children and absence of a sensitive non-invasive biomarker of early Fabry nephropathy. Accurate measurement of glomerular filtration rate and regular assessment for proteinuria and microalbuminuria are useful, though not sensitive enough to detect early lesions in the kidney. The principal clinical manifestationsin Fabry disease consist of artery associated complications (such as cerebral disease and nephropathy), but the pathophysiology of this specific vasculopathy is unclear. Several studies indicate that the specific vascular lesions that are present in Fabry disease occur as a result of vascular dysfunction with major components being endothelial dysfunction, alterations in cerebral perfusion and a pro-thrombotic phenotype. Fabry cardiac involvement has several clinical manifestations (table 10): concentric left ventricular hypertrophy without left ventricular dilation and severe loss of left ventricular systolic function, mitral and aortic valvulopathy, disorders of the atrioventricular conduction or repolarization, and compromised diastolic function. The neurological manifestations of Fabry disease include both peripheral nervous system and CNS involvement, with globotriaosylceramide accumulation found in Schwann cells and dorsal root ganglia together with deposits in CNS neurones. The main involvement of the CNS is attributable to cerebrovasculopathy, with an increased incidence of stroke. The abnormal neuronal accumulation of glycosphingolipid appears to have little clinical effect on the natural history of Fabry disease, with the possible exception of some reported mild cognitive abnormalities. The pathogenesis of Fabry vasculopathy remains poorly understood, but probably relates, in part, to abnormal functional control of the vessels, secondary to endothelial dysfunction as a consequence of α-galactosidase A deficiency. The diagnosis of Fabry disease is made in hemizygous males after the detection of the presence of angiokeratomas (fig 19 A, B), irregularities in sweating, edema, scant body hair, painful sensations, and of cardiovascular, gastrointestinal, renal, ophthalmologic, phlebologic, and respiratory involvement. A deficiency of alpha-gal A in serum, leukocytes, tears, tissue specimens, or cultured skin fibroblasts further supports the diagnosis in male patients. Since heterozygous women show angiokeratomas in only about 30% of cases and may have alpha-gal A levels within normal range, genetic analysis is recommended. The resultant storage of undegraded glycolipids leads to the progressive development of potentially life-threatening manifestations affecting multiple organ systems in the body. The Mainz Severity Score Index (MSSI) (table 12), a scoring system for patients with Fabry disease has been proven to be representative in patients with 'classic' Fabry disease and may be useful for monitoring clinical improvement in patients receiving enzyme replacement therapy. The MSSI of patients with AFD was significantly higher than that of patients with other severe debilitating diseases
The Natriuretic Peptide System: A Single Entity, Pleiotropic Effects
In the modern scientific landscape, natriuretic peptides are a complex and interesting network of molecules playing pleiotropic effects on many organs and tissues, ensuring the maintenance of homeostasis mainly in the cardiovascular system and regulating the water-salt balance. The characterization of their receptors, the understanding of the molecular mechanisms through which they exert their action, and the discovery of new peptides in the last period have made it possible to increasingly feature the physiological and pathophysiological role of the members of this family, also allowing to hypothesize the possible settings for using these molecules for therapeutic purposes. This literature review traces the history of the discovery and characterization of the key players among the natriuretic peptides, the scientific trials performed to ascertain their physiological role, and the applications of this knowledge in the clinical field, leaving a glimpse of new and exciting possibilities for their use in the treatment of diseases
Blood cyanide determination in two cases of fatal imtoxication: comparison between headspace gas chromatography and a spectrophotometric method
Blood samples of two cases were analyzed preliminarily by a classical spectrophotometric method (VIS) and by an automated headspace gas chromatographic method with nitrogen-phosphorus detector (HS-GC \u2044 NPD). In the former, hydrogen cyanide (HCN) was quantitatively
determined by measuring the absorbance of chromophores forming as a result of interaction with chloramine T. In the automated HS-GC \u2044NPD method, blood was placed in a headspace vial, internal standard (acetonitrile) and acetic acid were then added. This resulted in cyanide being liberated as HCN. The spectrophotometric (VIS) and HS-GC\u2044NPD methods were validated on postmortem blood samples fortified with potassium cyanide in the ranges 0.5\u201310 and 0.05\u20135 lg \u2044 mL, respectively. Detection limits were 0.2 lg \u2044mL for VIS and 0.05 lg \u2044mL for HS-GC\u2044NPD. This work shows that results obtained by means of the two procedures were insignificantly different and that they compared favorably. They are suitable for rapid diagnosis of cyanide in postmortem cases
Inflammation in ischemic stroke subtypes.
Determining the cause of stroke does influence choices for management. categorization of subtypes of ischemic stroke has had considerable study, but definitions are hard to formulate and their application for diagnosis in an individual patient is often problematic. Cerebral ischemia initiates a complex cascade of events at genomic, molecular, and cellular levels, and inflammation is important in this cascade. In 1993 for For the Trial of Org 10172 in Acute Stroke Treatment (TOAST), Adams et al] conducted a placebo-controlled, randomized, blinded study of the low-molecular-weight heparinoid given to patients within 24 hours after stroke and developed a system for diagnosis of subtype of ischemic stroke that uses components of existing diagnostic schemes. The type of acute ischemic stroke was classified according to the TOAST classification: 1) Large Artery AtheroSclerosis (LAAS); 2) CardioEmbolic Infarct (CEI); 3) LACunar infarct (LAC); 4) stroke of Other Determined Etiology (ODE); 5) stroke of UnDetermined Etiology (UDE) (see Fig. (1)). On the basis of pathophysiologic differences of each stroke subtype it's possible to hypothesize a different pattern of immuno-inflammatory activation in relation of ischemic stroke subtype. A nonspecific systemic inflammatory response occurs after both ischemic and hemorrhagic stroke, either as part of the process of brain damage or in response to complications such as deep venous thrombosis. Several studies have reported that higher levels of inflammatory markers such as C-reactive protein (CRP) and interleukin-6 (IL-6) are associated with worse outcome after ischemic stroke. Our group reported that patients with cardioembolic subtype showed significantly higher median plasma levels of TNF-α, IL-6, IL-1β whereas the lacunar subtype showed significantly lower median plasma levels of TNF-α, IL-6 and IL-1β. Our findings underlined the significant association was noted between the severity of neurological deficit at admission, the diagnostic subtype and some inflammatory variable
Early stages of the HFCVD process on multi-vicinal silicon surfaces studied by electron microscopy probes (SEM, TEM)
In this paper, we show that silicon dimples are suitable samples to study diamond nucleation on a controlled distribution of defects by SEM FEG and HRTEM observations. Indeed, multi-vicinal surfaces generated by a UHV thermal treatment have been characterised by STM experiments. On these terraces, we observed a strong increase of the nucleation density higher than two orders of magnitude compared to pristine silicon samples. Moreover, a preferential location of diamond nuclei along the steps is reported. This result is explained by the large surface diffusion length of carbon species compared to the terrace's width. Indeed, during the early stages of growth, oriented silicon carbide nano-crystals are observed with the relationship SiC(220)//Si(220)
Atherosclerosis as an inflammatory disease. ,
In many ways, atherosclerosis is a chronic inflammatory disorder and this issue is confirmed by recent investigations of that have focused on inflammation, providing new insight into mechanisms of disease. Several recent studies have addressed the role of chemokines in leukocyte accumulation in atherosclerosis, extending our knowledge and understanding of the complex and cell type-specific functions of chemokines in atherosclerosis. Activated T-lymphocytes within the atherosclerotic vessel wall express the CD40 ligand surface molecule, known to play a major role in several immunological pathways. In addition to activated T-lymphocytes, functional CD40 and CD40L are coexpressed by human vascular endothelial cells, smooth muscle cells and human macrophages in vitro as well as in situ in human atherosclerotic lesions. Recent studies indicate that CD40L activates atheroma-associated cells by promoting the expression of molecules thought to be involved in atherosclerosis, such as adhesion molecules, cytokines, matrix metalloproteinases, and tissue factor. Atherosclerosis starts with an innate immune response involving the recruitment and activation of monocytes macrophages that respond to an excessive accumulation of modified lipids within the arterial wall, followed by an adaptive immune response involving antigen-specific T lymphocytes. Effector T cells recognize modified auto-antigens such as oxidized LDL and heat shock proteins (i.e. HSP-60) that are presented by antigen-presenting cells such as macrophages or dendritic cells. The accumulation of inflammatory cells within the arterial wall leads to local production of chemokines, interleukins and proteases that enhance the influx of monocytes and lymphocytes, thereby promoting the progression of atherosclerotic lesions Recent reports have helped explain some of these questions by pointing to a role of contact dependent interaction between CD40 and CD40 ligand (CD40L, renamed CD154) as a stimulus for atheroma-associated cells. Also Macrophages play important roles in the progression of atherosclerosis by exhibiting unique characteristics under the various stimuli, evolving the plaque instability, thrombus formation and remodeling. Macrophage recruitment by abnormal endothelium over developing atherosclerotic plaques, is aided by endothelial expression of adhesion molecules (ICAM-1, VCAM, ELAM). The knowledge of atherosclerosis as an inflammatory disease offers the opportunity to develop novel therapeutic strategies targeting the inflammatory component of the disease
Neurological complications of Anderson-Fabry disease
Characteristic clinical manifestations of AFD such as acroparesthesias, angiokeratoma, corneal opacity, hypo/ and anhidrosis, gastrointestinal symptoms, renal and cardiac dysfunctions can occur in male and female patients, although heterozygous females with AFD usually seems to be less severely affected. The most prominent CNS manifestations consist of cerebrovascular events such as transient ischaemic attacks (TIAs) and (recurrent) strokes . For the most part, CNS complications in AFD have been attributed to cerebral vasculopathy, including anatomical abnormalities. The natural history of Fabry patients includes transitory cerebral ischaemia and strokes, even in very young persons of both genders. The mechanism is partly due to vascular endothelial accumulation of Gb-3. White matter lesions (WML) on MRI occur. Both males and females can be safely treated with enzyme replacement; and thus screening for Fabry disease of young stroke populations should be considered. There are, however, no hard data of treatment effect on mortality and morbidity. Stroke in Anderson-Fabry disease study of 721 patients with cryptogenic stroke, aged 18-55 years, showed a high prevalence of Fabry disease in this group: 5% (21/432) of men and 3% (7/289) of women. Combining results for both sexes showed that 4% of young patients with stroke of previously unknown cause had Fabry disease, corresponding to about 1-2% of the general population of young stroke patients. Cerebral micro- and macro-vasculopathy have been described in Fabry disease. Neuronal globotriaosylceramide accumulation in selective cortical and brain stem areas including the hippocampus has been reported by autopsy studies in FD, but clinical surrogates as well as the clinical relevance of these findings have not been investigated so far. Another Neurologic hallmarks of Fabry disease (FD) include small fiber neuropathy as well as cerebral micro- and macroangiopathy with premature stroke. Cranial MRI shows progressive white matter lesions (WML) at an early age, increased signal intensity in the pulvinar, and tortuosity and dilatation of the larger vessels. Conventional MRI shows a progressive load of white matter lesions (WMLs) due to cerebral vasculopathy in the course of FD. Another study has been conducted to quantify brain structural changes in clinically affected male and female patients with FD. The peripheral neuropathy in Fabry disease manifests as neuropathic pain, reduced cold and warm sensation and possibly gastrointestinal disturbances. Patients with Fabry disease begin having pain towards the end of the first decade of life or during puberty. Children as young as 6 years of age have complained of pain often associated with febrile illnesses with reduced heat and exercise tolerance. The patients describe the pain as burning that is often associated with deep ache or paresthesiae. Some patients also have joint pain. A high proportion of patients with Fabry disease is at increased risk of developing neuropsychiatric symptoms, such as depression and neuropsychological deficits. Due to both somatic and psychological impairment, health-related quality of life (QoL) is considerably reduced in patients with Fabry disease. Targeted screening for Fabry disease among young individuals with stroke seems to disclose unrecognized cases and may therefore very well be recommended as routine in the future. Furthermore, ischemic stroke is related to inflammation and arterial stiffness [and no study had addressed this relationship in patients with AF disease and cerebrovascular disease, so this topic could represent a possible future research line
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