422 research outputs found
Matrix Metalloproteases in Arterial Hypertension and their Trend after Antihypertensive Treatment
Background/Aims: Arterial hypertension is characterized by vascular remodelling, atherosclerosis and cardiovascular complications. Matrix metalloproteases (MPPs) are endopeptidases produced by all the cells present in the vascular wall and are involved in the regulation of the extracellular matrix protein turnover. MMPs contribute to blood vessel formation, remodelling, angiogenesis; whereas an altered expression or activity of MMPs or their tissue inhibitors (TIMPs) results correlated with the development and progression of cardiovascular complications. Methods: We examined the literature data regarding the role of MMPs in human hypertension, including their involvement in vascular remodelling, and the effects of some antihypertensive molecules on these MMP/TIMP profile. Results: The expression and the activity of some MMPs and TIMPs are impaired in human hypertension. An altered MMPs/TIMPs balance plays an important role in the vascular wall rearrangement, in response to hemodynamic changes which may induce myocardial hypertrophy and fibrosis leading to ventricular remodelling. Several studies have examined the effects of some antihypertensive molecules, such as ACE inhibitors, angiotensin receptor blockers, calcium-channel blockers, and aldosterone antagonists, on the MMPs/TIMPs profile by obtaining positive results. Conclusion: Considering the data taken into consideration, the authors believe that in clinical practice a strategic antihypertensive therapy directed to the MMPs profile, may be useful to decrease the risk of cardiovascular complications
Gelatinases and physical exercise: A systematic review of evidence from human studies
Matrix metalloproteinases (MMPs), particularly gelatinase A (MMP-2) and gelatinase B (MMP-9), as well as their tissue inhibitors (TIMP-1 and TIMP-2), are involved in the development of skeletal muscle tissue, in the repair process after muscle injury and in the adaptive modifications induced by physical exercise in skeletal muscle. This paper aims at reviewing results from human studies that investigated the role of gelatinases and their inhibitors in skeletal muscle response to acute physical exercise or training
Hemorheological abnormalities in human arterial hypertension
Blood rheology is impaired in hypertensive patients. The alteration involves blood and plasma viscosity, and the erythrocyte behaviour is often abnormal. The hemorheological pattern appears to be related to some pathophysiological mechanisms of hypertension and to organ damage, in particular left ventricular hypertrophy and myocardial ischemia. Abnormalities have been observed in erythrocyte membrane fluidity, explored by fluorescence spectroscopy and electron spin resonance. This may be relevant for red cell flow in microvessels and oxygen delivery to tissues. Although blood viscosity is not a direct target of antihypertensive therapy, the rheological properties of blood play a role in the pathophysiology of arterial hypertension and its vascular complications
Vibroacoustic Response of Pad Structures to Space Shuttle Launch Acoustic Loads
This paper presents a deterministic theory for the random vibration problem for predicting the response of structures in the low-frequency range (0 to 20 hertz) of launch transients. Also presented are some innovative ways to characterize noise and highlights of ongoing test-analysis correlation efforts titled the Verification Test Article (VETA) project
Fluidity and cytosolic Ca2+ concentration of circulating polymorphonuclear leukocytes at baseline in some chronic and acute clinical conditions: review of our survey
Abstract. Objective: In this mini-review we describe the behavior of polymorphonuclear leukocyte (PMN) membrane fluidity and of PMN cytosolic Ca2+ concentration in some chronic and acute clinical conditions.
Methods: PMN membrane fluidity was evaluated employing the fluorescent probe Fura-2AM, and PMN cytosolic Ca2+ concentration was evaluated using the fluorescent probe TMA-DPH. Results: From the determination of these two parameters investigated on resting PMNs, an almost constant increase in PMN cytosolic Ca2+ concentration in chronic clinical conditions, such as vascular atherosclerotic disease with and without diabetes mellitus, essential hypertension, chronic kidney disease, and diabetes mellitus of both types, and a decrease in PMN membrane fluidity in acute clinical conditions, such as juvenile acute myocardial infarction and acute ischemic stroke, are evident. Conclusion: The possible reasons for this different behavior are analyzed on the basis of pathophysiological considerations
Short-Term Prognosis of Juvenile Myocardial Infarction: Role of Plasma Viscosity
In our early research1 regarding the hemorheological pattern in
patients with acute myocardial infarction (AMI) with a mean
age of 61.45 + 10.99 years, we showed that the major hemorheological
parameters were almost normalized 2 weeks after
the acute event. In the last decade, we focused on hemorheological
parameters in juvenile myocardial infarction (JMI),
defined as AMI in patients aged 45 years, in the \u2018\u2018Sicilian
study on juvenile myocardial infarction\u2019\u2019
Nonstationary Transient Vibroacoustic Response of a Beam Structure
This study consists of an investigation into the nonstationary transient response of the Verification Test Article (VETA) when subjected to random acoustic excitation. The goal is to assess excitation models that can be used in the design of structures and equipment when knowledge of the structure and the excitation is limited. The VETA is an instrumented cantilever beam that was exposed to acoustic loading during five Space Shuttle launches. The VETA analytical structural model response is estimated using the direct averaged power spectral density and the normalized pressure spectra methods. The estimated responses are compared to the measured response of the VETA. These comparisons are discussed with a focus on prediction conservatism and current design practice
Optical evidence for a spin-filter effect in the charge transport of
We have measured the optical reflectivity of
as a function of temperature between 1.5 and 300
and in external magnetic fields up to 7 . The slope at the onset of the
plasma edge feature in increases with decreasing temperature and
increasing field but the plasma edge itself does not exhibit the remarkable
blue shift that is observed in the binary compound . The analysis of
the magnetic field dependence of the low temperature optical conductivity
spectrum confirms the previously observed exponential decrease of the
electrical resistivity upon increasing, field-induced bulk magnetization at
constant temperature. In addition, the individual exponential magnetization
dependences of the plasma frequency and scattering rate are extracted from the
optical data.Comment: submitted to Phys. Rev. Let
Behaviour of the neutrophil to lymphocyte ratio in young subjects with acute myocardial infarction
In the last years the neutrophil to lymphocyte ratio (NLR) has been examined in cardiovascular disorders and in particular in coronary artery disease and acute myocardial infarction (AMI). Now we examined this parameter in subjects with juvenile myocardial infarction at the initial stage and after 3 and 12 months. We enrolled 123 young subjects (112 men and 11 women, mean age 39.4\ub15.8 yrs) with AMI. The time interval between the AMI onset and the investigation was 13\ub17 days. The mean value of NLR observed in young AMI subjects was significantly increased compared to normal controls (N = 1.817\ub10.711; young AMI subjects = 2.376\ub10.873, p < 0.0001). NLR does not discriminate STEMI (2.427\ub10.878) and non STEMI (2.392\ub10.868) or diabetics (2.604\ub11.000) and non diabetics (2.324\ub10.853), but it differentiates smokers (2.276\ub10.853) and non smokers (2.837\ub11.072). NLR at the initial stage is not correlated with the number of cardiovascular risk factors or with the extent of the coronary disease. In this study we found a significant decrease of neutrophil count at 3 and 12 months later AMI without any significant variation of lymphocyte and consequently we observed a decrease in NLR at these two intervals of time in comparison with the initial stage. Despite some limitations present in this study, it is interesting to underline that also in juvenile myocardial infarction this low-cost haematological marker may be considered together with other inflammatory indicators
Leukocyte Rheology Before and After Chemotactic Activation in some Venous Diseases
AbstractObjective: to evaluate leukocyte rheology, polymorphonuclear leukocyte (PMN) membrane fluidity and cytosolic Ca2+ concentration in subjects with post-phlebitic leg syndrome (PPS) and acute deep-venous leg thrombosis (DVT). Subjects: twenty-two subjects with leg PPS and 14 subjects with leg DVT. Methods: we evaluated the leukocyte filtration (unfractionated, mononuclear cells (MN) and PMN), the PMN membrane fluidity and the PMN cytosolic Ca2+ concentration. Subsequently, we evaluated the same PMN variables after in vitro chemotactic activation with 4-phorbol 12-myristate 13-acetate (PMA) and N -formyl-methionyl-leucyl-phenylalanine (fMLP). Results: at baseline we observed a significant difference in the filtration variables of unfractionated and MN cells and in PMN cytosolic Ca2+ concentration. After activation, in normal subjects and subjects with PPS and DVT, a significant variation in PMN filtration at 5 and 15 minutes was evident. In normal subjects, no variation was present in PMN membrane fluidity or cytosolic Ca2+ concentration after activation. In subjects with PPS and DVT, we found a decrease in PMN membrane fluidity and an increase in PMN cytosolic Ca2+ concentration. After PMN activation (at 5 and 15 min) Δ% of IRFR distinguished normal subjects from subjects with PPS and DVT, while no difference was found in Δ% of membrane fluidity or cytosolic Ca2+ concentration. Conclusions: there is a functional alteration of leukocytes in these patients whose mechanisms are not yet clear
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