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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of 10-methoxy-1,6-dimethyl-ergoline-8 beta-methanol(5-bromonicotinate) (nicergoline, Sermion) on the energy metabolism in the animal CNS during and after cerebral hypoxia and ischemia have been studied by various authors by different methodological approaches. For this purpose both electrophysiological (EEG and cortically evoked potentials) and neurochemical parameters (adenylates, creatinphosphate and some intermediates of glycolysis and Krebs cycle) were analysed in dogs and cats. These studies concordantly show that nicergoline exerts a favourable activity during the post-hypoxic and post-ischemic period. In fact the recovery of the electrophysiological and neurochemical parameters is always more rapid in nicergoline-treated animals than in controls. The effects of nicergoline on the EEG pattern, on the energy potential and citrate concentration are particularly interesting.
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PMID:[Metabolic and neurochemical effects of nicergoline on the central nervous system. A review of the experimental studies (author's transl)]. 39 53

To determine possible mechanisms by which omental pedicles protect bronchial anastomoses from ischemia, we studied the angiogenic potential of a lipid extract of omentum. A rabbit cornea model was used to quantify neovascularization produced by methanol-chloroform extract of homogenized autologous omentum or perirenal fat. In 22 anesthetized rabbits, 10 microliters of omental lipid extract was injected into the cornea. In each animal the opposite eye was used as a control and was injected with a similar volume of extract prepared from perirenal fat. The side of injection of autologous omental fat was randomized and was not known to the investigator who assessed neovascularization on days 4, 7, 14, and 21 after injection. Neovascularization was recorded on microphotography and quantified by a point-counting method. Four days after injection, neovascularization in corneas injected with autologous omental fat was significantly (p less than 0.05) greater than in control corneas for all indices of neovascularization including total point count, which was three times greater than control. The angiogenic effect diminished with time, and by 21 days after injection corneal neovascularization was comparable for the two groups. Our results suggest that the lipid fraction of omentum has angiogenic activity that may stimulate neovascularization in ischemic tissues. Lack of sustained activity may be due to washout by neovessels or local tissue metabolism.
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PMID:Angiogenic factor: a possible mechanism for neovascularization produced by omental pedicles. 168 90

The Nauta impregnation method was used to map the neuronal changes in the canine lumbosacral segments following ischemia and reperfusion. The early perikaryal changes ensuing during the first phase after 30 min of thoracic aorta cross-clamping alone or followed by 30 min of reperfusion were mapped. During the second phase (one to six postischemic reperfusion days) the dendritic, preterminal and synaptic degeneration developed. The influence of 30 min cross-clamping immediately followed by perfusion fixation is characterized by the occurrence of flocculent argyrophilic clusters in the cytoplasm of middle-sized and large neurons of L3-S1 segments. Declamping of the thoracic aorta followed by 30 min of reperfusion basically modifies the susceptibility of lumbosacral neurons to Nauta impregnation promoting somatic and dendritic argyrophilia mainly of small (less than 15 microns) neurons, localized mostly in the fifth, sixth and seventh layers, respectively. This early appearing somatic and dendritic argyrophilia is not abolished by a pretreatment of sections with acetone in which cholesterol and its esters are highly soluble, or chloroform-methanol which extracts total lipid. After 24 h of reperfusion the somatic and dendritic argyrophilia is lost but the first signs of drop-like degeneration are detected in all but three superficial dorsal horn layers. At the end of the third reperfusion day, an atypical form of bouton degeneration was found, consisting of massive occurrence of enlarged (greater than 4 microns) boutons encircled by a clear halo. Laminar distribution of enlarged degenerating boutons coincides with laminar quantitative distribution of small argyrophilic neurons detected 30 min after reperfusion. The basic orientation of the many terminal fibres attached to enlarged boutons suggests that they belong to the axons localized mainly in the lateral and anterior columns. Despite a dense argyrophilic network pervading the gray matter of lumbosacral segments only pale shadows of middle-sized and large neurons were found at the end of the sixth reperfusion day and neither somatic nor vessel wall argyrophilia could be detected. All animals surviving one, three and six days postoperatively suffered from fully developed paraplegia.
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PMID:Mapping of the canine lumbosacral spinal cord neurons by Nauta method at the end of the early phase of paraplegia induced by ischemia and reperfusion. 172 92

Oxygen free radical reperfusion products may play a critical role in neonatal occlusive intestinal ischemia. We report a comparative analysis of light microscopy- and malonaldehyde (MDA)-derived fluorescent products as a measure of lipid peroxidation in occlusive intestinal ischemia in the rat. Weanling rats (n = 25) underwent cross clamping of the common mesenteric artery followed by various intervals of reperfusion; blood was sampled from the common mesenteric vein and the ileum was simultaneously biopsied. Blind-light microscopic scoring of the ischemic intestine was used. Fluorescent products were extracted using a chloroform/methanol/acidic water solvent extraction and measured with a spectrophotofluorometer using excitation/emission wavelengths of 360 and 430 nm, respectively. A trend was observed with prolonged reperfusion. Accumulation of fluorescent products correlated directly with the interval of reperfusion. Graded intervals of vascular occlusion produced progressive intestinal injury, but light microscopic analysis was not a sensitive index to distinguish the influence of graded reperfusion intervals. These data confirm a role for both ischemia and reperfusion in occlusive intestinal injury in the neonate and suggest that MDA accumulation may be a sensitive index of the reperfusion component of such injury.
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PMID:The role of reperfusion injury in occlusive intestinal ischemia of the neonate: malonaldehyde-derived fluorescent products and correlation of histology. 206 52

Anion chromatography methods have been developed to determine the concentrations of inositol phosphates and other water-soluble metabolites in rat brain. The cerebral cortex, hippocampus, and striatum were analyzed by chemically suppressed conductivity detection. Animals were sacrificed by directed microwave irradiation for more accurate estimations of in vivo concentrations. The effects of different sample preparation methods are compared. Trichloroacetic acid, formic acid, and perchloric acid extraction result in lower recoveries of phosphocreatine and other anions than does homogenization with water followed by chloroform-methanol extraction. The effects of postdecapitative ischemia on metabolite concentrations are determined. These methods will be used to study the effects of pharmacological agents on inositol phosphates and should be broadly applicable to the analysis of a variety of biological systems.
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PMID:Determination of inositol phosphates and other anions in rat brain. 276 Jan 61

Purine nucleotides, nucleosides, nucleobases, dinucleotides and nucleosides derivatives from acid-extracted rat liver and diaphragm were separated and quantitated by reversed-phase ion-pair high-performance liquid chromatography with a mobile phase composed of 90 mM potassium phosphate, 15 mM tetrabutylammonium hydroxide and a 1-30% methanol gradient. During 5 min of ischemia, adenine and guanine nucleotides decreased along with significant declines in NAD and increases in adenosine, inosine, hypoxanthine, xanthine, NADP and adenylosuccinate. Nitrobenzylthioinosine by gavage (5 mg/kg per day for five days) increased adenosine levels but without any alteration in nucleobase levels. Adenosine was shuttled to every available intracellular reservoir which included in declining order of magnitude GDP greater than adenosylhomocysteine greater than adenosine greater than ADP greater than AMP greater than IMP = XMP = GMP.
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PMID:Demonstration of the adenosine reservoirs with nitrobenzylthioinosine in liver and diaphragm by high-performance liquid chromatography. 339 39

A simple, sensitive HPLC method using fluorescence detection was developed for determination of adenosine in fetal venous perfusates of dual-perfused cotyledons from human term placentas. Maternal and fetal circuits of in vitro placental cotyledons were perfused with physiological salt solution containing dextrose and dextran (Earle's medium). Conditions were established for optimal formation of fluorescent 1,N6-ethenoadenosine from adenosine and chloroacetaldehyde in Earle's medium and for optimal resolution of 1,N6-ethenoadenosine by reversed-phase HPLC of the reaction mixture. The yield of 1,N6-ethenoadenosine was enhanced by dilution and acidification of the sample matrix. Perfusate samples in autosampler vials were diluted 40% with water and reacted with chloroacetaldehyde for 40 min at 100 degrees C; replicate 100-microliters injections were made automatically from each reaction mixture for HPLC analysis with fluorescence detection on a column packed with 3 microns octadecylsilica (Hypersil). Calibration curves were prepared similarly from 4-100 nM adenosine in Earle's medium. Alternatively, perfusate samples were diluted twofold with dilute phosphoric acid to give a final pH of 5.4 before reaction with chloroacetaldehyde, and replicate 50-microliters injections were made automatically for HPLC; calibration curves were prepared from 2-400 nM adenosine in Earle's medium. 1,N6-Ethenoadenosine was well resolved from Earle's-derived artifactual peaks on chromatography with either a linear or a concave gradient of methanol in ammonium phosphate buffer. Total run times were 15 and 19 min, respectively. Sensitivity of measurement of adenosine was 2-4 nM. Derivatization of adenosine using the acidified reaction mixture gave a limit of detection of 100 fmol of adenosine per injection. Application of the method to analysis of adenosine in fetal venous perfusates of eight dual-perfused cotyledons, each from a different placenta, gave a range of 3.5-52 nM adenosine. Ischemia, imposed by cessation of maternal perfusion, caused a two- to sixfold increase in fetal venous perfusate adenosine concomitant with an increase in fetoplacental perfusion pressure; perfusion pressure and perfusate adenosine returned to baseline levels on reperfusion of the maternal circuit. This facile method of determination of perfusate adenosine should allow investigation of the role of placental adenosine release in regulation of fetoplacental vascular resistance and should be applicable to study of adenosine released by other isolated perfused organs.
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PMID:Determination of adenosine in fetal perfusates of human placental cotyledons using fluorescence derivatization and reversed-phase high-performance liquid chromatography. 340 8

To facilitate evaluation of the influence of myocardial phospholipid metabolites on the development of electrophysiologic abnormalities induced by ischemia, a method for the quantification of choline and ethanolamine phospholipids suitable for accurate and reproducible analysis of small amounts of myocardium was developed. The procedure combines chloroform and methanol extraction of phospholipids after tissue homogenization with subsequent separation by sequential thin-layer and high-performance liquid chromatography. Phosphorus in purified lipid classes was determined with the correction for recovery based on 14C-labeled internal standards.
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PMID:Quantification of choline and ethanolamine phospholipids in rabbit myocardium. 398 27

Lysolecithin (lysoglycerophosphocholine, LPC) was isolated from rat cerebral cortex and quantitatively analyzed at various times after postdecapitative ischemic treatment. In addition, different procedures for extraction and analysis of the LPC in brain were evaluated. Results indicated that LPC can be quantitatively extracted into the organic phase using the conventional extraction procedure with chloroform-methanol (2:1, vol/vol). However, care should be taken to avoid using strong acids, which can hydrolyze the alkenylether side chain of the plasmalogens, resulting in the release of 2-acylphospholipids. Quantitative GLC analysis using myristoyl-LPC as internal standard revealed a level of 1.8 nmol LPC/mg protein in brain with acyl groups comprised mainly of 16:0, 18:0, and 18:1. The acyl group profile reflects that the LPC are derived mainly from phospholipase A2 action. An increase of 46% in the LPC level was observed at 1 min after ischemic treatment, but this was followed by a steady decline. Ischemia induced an increase in the LPC species that are enriched in 18:0 and 18:1 fatty acids. The transient appearance of LPC during ischemia further suggests that this phospholipid is undergoing active turnover, possibly hydrolysis by the lysophospholipase. This mechanism of action may account, at least in part, for the increase in both saturated and unsaturated fatty acids during the early phase of the ischemic treatment.
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PMID:On the status of lysolecithin in rat cerebral cortex during ischemia. 647 Jul 8

The gastric microvascular changes in reserpine (RES 6 mg/kg s.c.)-induced ulcer in Wistar male rats were studied. Two kinds of water paints were injected through the superior mesenteric vein and celiac artery. Excised stomachs were frozen instantly by cooled methanol (-70 degrees C) and were put into methylsalicylate after 24 hr in order to make transparent preparations. RES caused constriction of the vein from the middle layer till the muscularis mucosae and congestion with ischemia in the gastric mucosa after 1 hr. Even after 3 hr, these vascular changes remained and were accompanied by erosion. After 6 and 9 hr, the erosion became more severe, while ischemia was no longer found and the vessels were rather dilated. These lesions initiated from the fundic-antral border area in the lesser curvature and gradually extended to the greater curvature. The early changes up to 3 hr were inhibited by phentolamine, isoproterenol, C6, metiamide and methysergide, but not by carbachol, atropine, vagotomy and propranolol. Atropine, vagotomy, isoproterenol, propranolol and C6 inhibited erosion in the late stage. Phentolamine, carbachol, diphenhydramine, metiamide and methysergide were not effective. From these results and the gastric movement caused by RES, it is suggested that the vascular changes of the early stage in RES-induced ulcer are due not only to the autonomic nervous system but also to the endogenous biogenic amines, and the erosions in the late stage depend on the hypermotility of the stomach rather than on the hypersecretion of the stomach.
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PMID:[Changes of gastric mucosal vessels in reserpine-induced ulcer (author's transl)]. 708 19


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