Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Information is lacking regarding dynamic platelet accumulation at the site of the occluded middle cerebral artery (MCA) and the relationship between platelet aggregation in downstream cerebral microvessels and loss of perfusion and vascular integrity of these microvessels. In the present study, we employed a model of embolic MCA occlusion in the rat to simultaneously measure temporal and spatial profiles of platelet accumulation at the site of the embolus occluding the MCA and within downstream cerebral microvessels. We also measured the integrity of microvessels and matrix metalloproteinase (MMP) activity in ischemic brain. Rats (n=36) were subjected to embolic MCA occlusion. Immunohistochemistry was used to detect microvascular integrity, plasminogen activator inhibitor 1 (PAI-1) and the deposition of fibrin. SDS-PAGE zymography was used to measure MMP2 and MMP9 activities. Accumulation of platelets and increases in PAI-1 immunoreactivity at the site of the embolus occluding the MCA were detected 1 h (n=7) and 4 h (n=7) after ischemia, respectively, and numbers of GPIIb/IIIa immunoreactive downstream cerebral microvessels increased significantly (209+/-59; n=7; P<0.05) 4 h after ischemia, suggesting dynamic platelet aggregation. A significant (n=7; P<0.01) diffuse loss of type IV collagen immunoreactivity in microvessels was temporally associated with platelet GPIIb/IIIa immunoreactivity within the vessels. Triple immunostaining revealed that microvessels containing platelet aggregates exhibited loss of type IV collagen immunoreactivity and both intra- and extra-vascular fibrin deposition, suggesting that intravascular platelet aggregation is associated with decreases in the integrity of the microvascular basal lamina and blood-brain barrier leakage. A significant increase (P<0.05) in MMP9 was detected at 4 h (n=3) and 24 h (n=3) after ischemia but levels of MMP2 were not significantly changed in ischemic brain. Our data suggest that dynamic platelet aggregation in ischemic brain may contribute to time-dependent resistance to fibrinolysis. In addition, platelet deposition and increased MMP9 coincided with degradation of type IV collagen and loss of vascular integrity. These data suggest an important role for post-occlusive distal platelet deposition in the pathophysiology of stroke.
 ...
PMID:Dynamic platelet accumulation at the site of the occluded middle cerebral artery and in downstream microvessels is associated with loss of microvascular integrity after embolic middle cerebral artery occlusion. 1153 35

Myocardial perfusion SPECT (MPS) commonly is interpreted qualitatively and not quantitatively. Most of the prognostic literature is based on a semi-quantitative visual analysis (SQA) of MPS. However, data about the comparison between the SQA and coronary angiography (cath) is lacking. We therefore evaluated 167 patients who underwent MPS and subsequent cath. SQA using a 20 segment model was used for MPS interpretation. Patients with a small to moderate amount of ischemia (SDS < or = 4; mean 1.2 +/- 1.5) and with extensive ischemia (SDS > 4; mean 9.6 +/- 4.7) were then compared with respect to clinical and cath variables. Patients with extensive ischemia had more advanced CAD as demonstrated by several cath variables (more often triple vessel and LAD-disease). SQA therefore is a useful tool for MPS interpretation and decision making in patients with (suspected) CAD.
 ...
PMID:[Noninvasive cardiac diagnosis for quantifying scarring, ischemia and pump function within the scope of a study. 20 useful facets in routine cardiology nuclear medicine practice]. 1201 64

To determine the activity of matrix metalloproteinases (MMP), especially MMP-2 and MMP-9, which play an important role in ischemic stroke and intracerebral hemorrhage, we adapted a simple and rapid method for localizing gelatinase activity to a gelatin film in situ-overlay technique previously used in cancer research. Ten micrometer cryosections of rat brain from controls and animals subjected to 3 h of ischemia and 48 h of reperfusion (suture model for transient cerebral ischemia) were used. After thawing, a gelatin film with a polyester base was put on the slide, incubated for 24 h at 37 degrees C, stained with Ponceau S, and then discolored in bi-distilled water. Non-staining areas on the film corresponded to lysis zones, caused by activated MMPs. This was proven by MMP incubation at various concentrations on the plain gelatin film and pretreatment with EDTA (an MMP inhibitor), which prevents lysis zones in normal and ischemic brains. As confirmatory tests, SDS-PAGE zymography was used to define MMP activity, and also MMP-2 immunohistochemistry to detect the possibly cellular origin of MMPs. Normal rat brain exhibited a low background activity, which was visible as a light halo-like lysis zone over and around the brain. Areas in normal brain with medium MMP activity were within the white matter (corpus callosum, anterior commissure, and cerebellum). Ischemic brain exhibited high activity lysis zones within the infarcted area (detected by microtubuli associated protein-2 staining). These zones consisted of microscopically small lysis holes with a diameter of about 10-20 microm. Immunohistochemistry showed that especially microvessels expressed MMP antigen. SDS-PAGE zymography differentiated between a high level of activated MMPs in the ischemic area and a low level in the non-ischemic basal ganglia. The gelatin film in situ-overlay technique is able to localize MMP activity in ischemic rat brain tissue on a microscopic level.
 ...
PMID:A gelatin in situ-overlay technique localizes brain matrix metalloproteinase activity in experimental focal cerebral ischemia. 1204 62

Biotin-cysteine was used to study protein S-thiolation in isolated rat kidneys subjected to ischemia and reperfusion. After 40 min of ischemia, total protein S-thiolation increased significantly (P < 0.05), by 311%, and remained significantly elevated (P < 0.05), 221% above control, after 5 min of postischemic reperfusion. Treatment of protein samples with 2-mercaptoethanol abolished the S-thiolation signals detected, consistent with the dependence of the signal on the presence of a disulfide bond. With the use of gel filtration chromatography followed by affinity purification with streptavidin-agarose, S-thiolated proteins were purified from CHAPS-soluble kidney homogenate. The proteins were then separated by SDS-PAGE and stained with Coomassie blue. With a combination of matrix-assisted laser desorption ionization time of flight mass spectrometry and LC/MS/MS analysis of protein bands digested with trypsin, a number of S-thiolation substrates were identified. These included the LDL receptor-related protein 2, ATP synthase alpha chain, heat shock protein 90 beta, hydroxyacid oxidase 3, serum albumin precursor, triose phosphate isomerase, and lamin. These represent proteins that may be functionally regulated by S-thiolation and thus could undergo a change in activity or function after renal ischemia and reperfusion.
 ...
PMID:Reversible cysteine-targeted oxidation of proteins during renal oxidative stress. 1287 48

Regulation of protein function by reversible cysteine-targeted oxidation can be achieved by multiple mechanisms, such as S-glutathiolation, S-nitrosylation, sulfenic acid, sulfinic acid, and sulfenyl amide formation, as well as intramolecular disulfide bonding of vicinal thiols. Another cysteine oxidation state with regulatory potential involves the formation of intermolecular protein disulfides. We utilized two-dimensional sequential non-reducing/reducing SDS-PAGE (diagonal electrophoresis) to investigate intermolecular protein disulfide formation in adult cardiac myocytes subjected to a series of interventions (hydrogen peroxide, S-nitroso-N-acetylpenicillamine, doxorubicin, simulated ischemia, or metabolic inhibition) that alter the redox status of the cell. More detailed experiments were undertaken with the thiol-specific oxidant diamide (5 mm), a concentration that induces a mild non-injurious oxidative stress. This increase in cellular oxidation potential caused global intermolecular protein disulfide formation in cytosolic, membrane, and myofilament/cytoskeletal compartments. A large number of proteins that undergo these associations were identified using liquid chromatography-mass spectrometry/mass spectrometry. These associations, which involve metabolic and antioxidant enzymes, structural proteins, signaling molecules, and molecular chaperones, were confirmed by assessing "shifts" on non-reducing immunoblots. The observation of widespread protein-protein disulfides indicates that these oxidative associations are likely to be fundamental in how cells respond to redox changes.
 ...
PMID:Detection and mapping of widespread intermolecular protein disulfide formation during cardiac oxidative stress using proteomics with diagonal electrophoresis. 1529 44

A hemorrhagic metalloproteinase has been isolated from Bothrops alternatus venom from specimens that inhabit the north-east region of Argentina. The present study aimed at evaluating the proteolytic, hemorrhagic, edematogenic and myotoxic activities of the purified metalloproteinase, in order to consider its participation on the phatophysiology of the intoxication by Bothrops alternatus venom. The hemorrhagic metalloproteinase was isolated by a combination of DEAE-Cellulose chromatography and gel filtration on Sephadex G-75. The enzyme showed a molecular mass around 55k Da, it exhibited a hemorrhagic activity with a minimal hemorrhagic dose of 1.9 microg, almost two fold minor than the whole venom (3.6 microg). The enzyme showed a weak proteolytic activity on casein (18.72 U/mg enzyme), similar to the one exhibited by the whole venom (20 U/mg venom). Besides, the ability to degrade casein could be detected by SDS-PAGE; beta-casein was the fraction that showed the higher degradation, followed by alphas(1)-casein and kappa-casein degradation. The hemorrhagic metalloproteinase rapidly hydrolysed the A alpha-chain of fibrinogen, followed by B beta-chain degradation and leaving the gamma-chain unaffected. Proteolytic activities were inhibited by EDTA whereas they were not inhibited by benzamidine and PMSF. The metalloproteinase showed several polypeptides chains after autocatalytic processing, including a chain of 28k Da, it could be the processed disintegrin-like and cysteine-rich domains. The isolated enzyme exhibited myotoxic activity with high CK levels at 6h, due to local ischemia resulting of its hemorrhagic activity, and a significant edema-inducing effect (MED=1.3 microg), corroborated both results by the histological observations of samples of gastrocnemius muscle. These findings showed that this hemorrhagic metalloproteinase, possesses high edematogenic and myotoxic activities and, in despite of exhibiting a weak proteolytic activity, it is able to degrade fibrinogen. So, this enzyme would contribute markedly to the phatophysiology of the bothropic envenomation.
 ...
PMID:Proteolytic, edematogenic and myotoxic activities of a hemorrhagic metalloproteinase isolated from Bothrops alternatus venom. 1613 35

Calpain-1 is a ubiquitous intracellular Ca2+-activated protease, which has been implicated in the pathogenesis of reversible myocardial depression (i.e. myocardial stunning) that follows ischemia and reperfusion via myofibrillar protein degradation. However, the target proteins of this degradative process in the human myocardium have not yet been identified. In order to compare the levels of Calpain-1 susceptibility within a set of human myofibrillar proteins (titin, alpha-fodrin, desmin, troponin T (cTnT), troponin I (cTnI) and alpha-actinin), crude left ventricular tissue homogenates were incubated for 0.5, 15, 30, 60 or 120 min in the presence of Calpain-1 (1 U or 5 U). Differences in the kinetics and extents of protein degradation were subsequently evaluated by using silver-stained SDS-polyacrylamide gels and Western immunoblot analyses. These assays revealed myofibrillar proteins with high (titin and alpha-fodrin), moderate (desmin and cTnT), or low (cTnI and alpha-actinin) relative Calpain-1 susceptibilities. The level of phosphorylation of cTnI did not explain its relatively low Calpain-1 susceptibility. Moreover, the molecular mass distributions of the truncated alpha-fodrin, desmin and cTnI fragments resulting from Ca2+-dependent autoproteolysis exhibited marked similarities with those of their Calpain-1-clipped products. These in vitro results shed light on a number of structural (titin, alpha-fodrin, desmin and alpha-actinin) and regulatory (cTnT and cTnI) proteins within the contractile apparatus as potential targets of Calpain-1. Their degradation may contribute to the development of postischemic stunning in the human myocardium.
 ...
PMID:Calpain-1-sensitive myofibrillar proteins of the human myocardium. 1618 82

Seventy-two pediatric kidney recipients of living related donors (LRD) and 145 of cadaveric donors (CAD) were analyzed for height standard deviation scores (Ht-SDS) and glomerular filtration rates (GFR) directly after transplantation and over the following 5 years. GFR was significantly higher immediately after transplantation in LRD compared with CAD recipients; however, GFR was not different during the 5-year follow-up period. Although Ht-SDS was comparable at the time of transplantation in both groups, it was significantly higher among LRD recipients over the next 5 years. Multivariate and covariate analyses showed that Ht-SDS after 5 years was mainly influenced only by CAD vs LRD and not by GFR or other factors, namely, donor age, rejections, time of dialysis, preemptive transplantation, age at transplantation, or immunosuppression. Thus, children receiving grafts from LRD showed a better catch-up growth independent of the GFR than those after CAD transplantation. We concluded that the period of donor death and prolonged cold ischemia in CAD grafts may lead to changes in gene expression of cytokines and other mediator molecules that affect bone metabolism. Better growth seems to be an additional factor supporting the policy of LRD kidney transplantation as the best option in children.
 ...
PMID:Living related kidney donation as an advantage for growth of children independent of glomerular filtration rate. 1664 44

Immuno-proteasome is thought to be responsible for the processing of intracellular antigens and is induced when cells are treated with the inflammatory cytokines promoting cellular immunity. We tested the possibility that immuno-proteasome can be up-regulated in renal cells exposed to a long-lasting ischemia and inflammation in an experimental model of two-kidney, one-clip renovascular hypertension in the rat. Western blotting showed that immuno-proteasome subunit, LMP7, was up-regulated in the clipped ischemic kidney that was atrophic, but not in the contralateral unclipped kidney that underwent compensatory hypertrophy. Immunohistochemical analysis revealed that LMP7 was highly expressed in cortical epithelial and endothelial cells of the ischemic kidney. Surprisingly, the second immuno-subunit, LMP2, was almost undetectable, indicating that renal ischemia may induce exclusively the LMP7 subunit. We also found that renal ischemia neither reduced the SDS-stimulated proteasomal activity nor affected a high level of the PA28 activator. Thus, the results provide evidence that LMP7 immuno-subunit is induced in renal cells exposed to a long-lasting renal ischemia and inflammation, and that there is a direct link between LMP induction and renal atrophy. This opens an opportunity to study a role for LMP-containing proteasomes in the kidneys and other organs undergoing reduction in mass in diseases accompanied by a long-lasting ischemia and inflammatory responses.
 ...
PMID:Immuno-proteasome subunit LMP7 is up-regulated in the ischemic kidney in an experimental model of renovascular hypertension. 1676 38

A simple and rapid MEKC method was developed for the simultaneous determination of myo-inositol, scyllo-inositol, and glucose. Prior to electrophoretic separation, the nonfluorescent inositols and glucose were derivatized by N-methylisatoic anhydride at 25 degrees C for 10 min so that they could be detected by a fluorescence detector during separation. The good separation with high efficiency by MEKC was achieved in 13 min with a glycine buffer containing SDS and PEG 4000. Several parameters affecting the separation were studied, including the pH of BGE, the concentrations of glycine, SDS, and PEG 4000, and the applied voltage. Using glycerol as an internal standard, the linear ranges of the method for myo-inositol, scyllo-inositol, and glucose were 0.03-10, 0.01-5, and 0.05-20 mM; the concentration LODs of myo-inositol, scyllo-inositol, and glucose were 0.020, 0.0078, and 0.026 mM, respectively. The method was applied to analyze extracellular myo-inositol and glucose in the microdialysates from rat brain cortex of ischemia animal model and intracellular myo-inositol and scyllo-inositol in the rat brain extract.
 ...
PMID:Simultaneous determination of myo-inositol and scyllo-inositol by MEKC as a rapid monitoring tool for inositol levels. 1735 85


<< Previous 1 2 3 4 5 6 7 Next >>