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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The importance of nutrition in protecting the living organism against the potentially lethal effects of reactive oxygen species and toxic environmental chemicals has recently been realized. This new perspective has prompted re-evaluation of the food constituents of human diet from the point of view of their nutritional adequacy, deficiency and toxicity. The biological antioxidant defense system is an integrated array of enzymes, antioxidants and free radical scavengers. These include glutathione reductase, glutathione-s-transferase, glutathione peroxidase, phospholipid hydroperoxide glutathione peroxidase, superoxide dismutase (SOD) and catalase, together with the antioxidant vitamins C, E and A. The individual components of this system get utilized in various physiological process and for chemoprotection and therefore require replenishment from the diet. Other components of the diet like carbohydrates, proteins and lipids are important for maintaining the levels of various enzymes required in body's defense system providing protection against carcinogens. However, the emerging newer concepts focus on the role of trace elements and other dietary components in antioxidant defense and detoxification mechanisms. Trace elements like Iron, zinc magnesium, selenium, copper, and manganese are some of the elements involved in antioxidant defense mechanisms. Inadequate intake of these nutrients has been associated with ischemic heart disease, arthritis, stroke and cancer, where pathogenic role of free radicals is suggested. Further the importance of diet in the prevention of chemical induced toxicity can not be undetermined. Recent reports on the role of bioflavonoids as antioxidents and their potential use to reduce the risks of coronary heart disease and cancer in human beings have opened a new arena for future research. Induction of the cytochrome P450 isoenzymes by food pyrolysis, mutagens, alcohol and fasting, on the other hand is reported to contribute to chemical toxicity and carcinogenecity. Certain chemicals moieties in the food are mutagenic and carcinogenic.
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PMID:Role of nutrition in toxic injury. 1064 Nov 28

Zinc and copper are endogenous transition metals that can be synaptically released during neuronal activity. Synaptically released zinc and copper probably function to modulate neuronal excitability under normal conditions. However, zinc and copper also can be neurotoxic, and it has been proposed that they may contribute to the neuropathology associated with a variety of conditions, such as Alzheimer's disease, stroke, and seizures. Recently, we demonstrated that carnosine, a dipeptide expressed in glial cells throughout the brain as well as in neuronal pathways of the visual and olfactory systems, can modulate the effects of zinc and copper on neuronal excitability. This result led us to hypothesize that carnosine may modulate the neurotoxic effects of zinc and copper as well. Our results demonstrate that carnosine can rescue neurons from zinc- and copper-mediated neurotoxicity and suggest that one function of carnosine may be as an endogenous neuroprotective agent.
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PMID:Endogenous mechanisms of neuroprotection: role of zinc, copper, and carnosine. 1066 95

Free radical are highly reactive chemical species with an unpaired electron in an atomic or molecular orbital. In biological systems, the most important free radicals are superoxide anion and hydrogen peroxide; in the presence of transition metals such as iron, copper and manganese both these free radicals produce hydroxyl radicals. Free radicals attack proteins, nuclei acids and membranes containing large quantities of polyunsaturated fatty acids. Because of their toxicity, the organism has developed ways to deactivate them. The superoxide dismutase enzyme (SOD) catalyzes dismutation of the superoxide radical into hydrogen peroxide and oxygen hydrogen peroxide is in turn reduced to water and oxygen by peroxidase glutathione and catalase enzymes. The production of radicals in the brain is due to catecholamine metabolism such as dopamine and norepinephrine and is increased by the presence of transition metals and by a deficiency of antioxidant agents such as vitamin E. Two main groups of dementia exist in older age: the multi-infarctual dementias, caused by cerebrovascular disorders and the primary degenerative disorders such as Alzheimer, where no vascular disease is evident. Free radicals play an important role in Parkinson's disease, in Alzheimer's disease and in stroke. The value of SOD and CAT activity following the above mentioned degenerative diseases differ among the various studies carried out. In Alzheimer's disease, the value of SOD activity probably increases in the neuropathologically involved areas. In stroke, the SOD value does not vary either in the ischemic area or in the peri-infarctual one during the first 24 hrs after lesion, while the CAT value decreases.
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PMID:Free radicals: important cause of pathologies refer to ageing. 1070 16

This review examines interactions in the mammalian central nervous system (CNS) between carnosine and the endogenous transition metals zinc and copper. Although the relationship between these substances may be applicable to other brain regions, the focus is on the olfactory system where these substances may have special significance. Carnosine is not only highly concentrated in the olfactory system, but it is also contained in neurons (in contrast to glia cells in most of the brain) and has many features of a neurotransmitter. Whereas the function of carnosine in the CNS is not well understood, we review evidence that suggests that it may act as both a neuromodulator and a neuroprotective agent. Although zinc and/or copper are found in many neuronal pathways in the brain, the concentrations of zinc and copper in the olfactory bulb (the target of afferent input from sensory neurons in the nose) are among the highest in the CNS. Included in the multitude of physiological roles that zinc and copper play in the CNS is modulation of neuronal excitability. However, zinc and copper also have been implicated in a variety of neurologic conditions including Alzheimer's disease, Parkinson's disease, stroke, and seizures. Here we review the modulatory effects that carnosine can have on zinc and copper's abilities to influence neuronal excitability and to exert neurotoxic effects in the olfactory system. Other aspects of carnosine in the CNS are reviewed elsewhere in this issue.
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PMID:Interactions between carnosine and zinc and copper: implications for neuromodulation and neuroprotection. 1095 Oct 99

The aim of this work was the evaluation of low density lipoprotein (LDL) susceptibility to oxidation in the survivors of ischaemic stroke. The investigations were performed in 65 individuals at least three months after the onset of acute symptoms. In 24 patients stroke was caused by alterations in main cerebral arteries, in 19 by considerable narrowing of carotid artery, in 15 by alterations in small cerebral arteries with often accompanying hypertension and/or diabetes (lacunar stroke) and in 7 by embolism of cardiac origin in individuals with cardiac arrhythmia and coronary artery disease. The control group comprised 25 age matched persons without pathological symptoms. Plasma lipids and apolipoprotein B levels were determined as well as two antioxidants: alpha-tocopherol level and superoxide dismutase activity. The evaluation of lipid peroxidation was performed by determining thiobarbituric acid reacting substances (TBARS) and lipid peroxides (LPO) increase after 5 hours oxidation of isolated LDL in vitro in the presence of copper ions. The level of IgG directed against modified LDL was also evaluated. In the patients decreased HDL cholesterol level was observed as well as increased apolipoprotein B. In the group of thrombotic strokes high triglycerides were observed. alpha-tocopherol level was decreased in the group of cerebral strokes. The amounts of oxidation products did not differ between the whole group of patients after stroke and the controls. A significant increase concerned only the group of lacunar strokes. The evaluation of LDL susceptibility to oxidation in patients after stroke by measuring absorption at 234 nm and determining the time period necessary to the onset of intensive LDL oxidation will be the subject of a separate publication.
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PMID:[In vitro oxidation of low density lipoproteins in patients after ischemic stroke]. 1097 39

Zinc (Zn) and copper (Cu) concentrations in hair and urine of patients diagnosed and hospitalized for myocardial infarction (MI patients) and in their descendants (MI descendants) were estimated and compared with their age-matched healthy volunteers with no family history of MI (control group and control descendants). The data revealed approximately twofold higher Zn and twofold lower Cu in the urine of the patients; Zn was lower and Cu was higher in the urine of MI descendants than those of the patients (p < 0.001), but Zn in hair and urine was higher and Cu in hair was lower in MI descendants compared with their control counterparts (p < 0.001). The data suggested that there was a consistent rise in Zn and fall in Cu reserves in the genetically predisposed subjects (MI descendants) prior to the manifestation of clinical symptoms. Based on this, the data were subjected to logistic regression and a model was obtained to predict the susceptibility to MI (LR-MI), having impact factors values as follows: constant (C), -3.342; impact factor of body mass index, -0.776; impact factor of hair Zn, -2.449; impact factor of urine Zn, +3.441; impact factor of hair Cu, -15.077; impact factor of urine Cu, -24.153. For the equation Y = e(x)/(1 + e(x)), the value of x was obtained as follows: -3.342 + [BMI (kg/m2) (-0.776)] + [Hair Zn (micromol/g) (-2.449)] + [Urine Zn (micromol/L) (3.441)] + [Hair Cu (micromol/g) (-15.077)] + [Urine Cu (micromol/L) (-24.153)]. On substituting the values of BMI, hair Zn, urine Zn, hair Cu, and urine Cu in x, the response variable Y as zero for healthy controls and 0.99 or 99.9% susceptibility in MI patients were obtained. In between these two extremes, the response variable ranged between 0 and 0.99 or 99.9% susceptibility to MI in their descendants. It is envisaged that the MI patients have an operational component of a genetic disorder of ionic imbalance at a young age that can be exploited in making a prediction of susceptibility to heart stroke in individuals much before its onset and diagnosis in asymptomatic patients, particularly in genetic and epidemiological studies of MI.
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PMID:Detection of potentially myocardial infarction susceptible individuals in indian population: a mathematical model based on copper and zinc status. 1105 7

A 67-year-old woman had frequent subacute ileus, hearing difficulty, muscle atrophy and stroke-like episodes. Computed tomography revealed multiple low-density areas, which did not correlate with the vascular supply, in the cerebral cortex. She had metabolic disturbance comprising lactic acidosis and elevated pyruvate level. Her skeletal muscle biopsy specimen showed ragged-red fibers, and mitochondrial DNA analysis revealed a point mutation at position 3243, findings consistent with MELAS. Examination of her small intestine revealed a necrotic zone and numerous abnormal large mitochondria in the smooth muscle cells, vascular media and endothelium, and intestinal ganglion cells. The cerebral cortex showed multiple microcystic necrotic foci in cerebral cortex. Cactus-like pathology resembling the changes associated with Menkes' kinky hair disease and torpedoes were observed in the cerebellar Purkinje cells. The intestinal dysmotility due to MELAS and cerebellar changes were presumed to be associated with a disturbance of copper metabolism.
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PMID:Mitochondrial encephalomyopathy with lactic acidosis and stroke like episodes (MELAS) with prominent degeneration of the intestinal wall and cactus-like cerebellar pathology. 1107 25

Heme-hemopexin (2-10 microM) is used as a model for intravenous heme released in trauma, stroke, and ischemia-reperfusion. A transient increase in cellular protein oxidation occurs during receptor-mediated heme transport from hemopexin which is inhibited by the nonpermeable Cu(I) chelator, bathocuproinedisulfonate. Thus, participation of surface redox process involving Cu(I) generation are proposed to be linked to the induction of the protective proteins heme oxygenase-1 (HO-1) and metallothionein-1 (MT-1) by heme-hemopexin. The region (-153 to -42) in the proximal promoter of the mouse MT-1 gene responds to heme- and CoPP-hemopexin in transient transfection assays and contains metal-responsive elements for MTF-1 and an antioxidant-responsive element (ARE) overlapping a GC-rich E-box to which USF-1 and -2 bind. No decreases in DNA binding of the diamide-oxidation sensitive USF-1 and -2 occur upon exposure of cells to heme-hemopexin. MTF-1 and the ARE-binding proteins are relatively resistant to diamide oxidation and are induced approximately eight- and two-fold, respectively, by heme-hemopexin. BCDS prevents the nuclear translocation of MTF-1 by both heme- and CoPP-hemopexin complexes as well as MT-1 mRNA induction by CoPP-hemopexin. Thus, copper is needed for the surface oxidation events and yet the nuclear translocation of MTF-1 in response to hemopexin occurs via copper, probably Cu(I),-dependent signaling cascades from the hemopexin receptor rather than the oxidation per se.
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PMID:Role for copper in transient oxidation and nuclear translocation of MTF-1, but not of NF-kappa B, by the heme-hemopexin transport system. 1121 79

To facilitate international multicentre studies and quality control of infant pulmonary function measurements, the European Respiratory Society-American Thoracic Society (ERS-ATS) working group for infant lung function testing aims to develop specifications for standardized infant lung function equipment and software. However, a standardized test device is also needed to test whether existing infant lung function equipment is able to meet these requirements. The authors have built a "mechanical model baby" consisting of a linear pump which can reproduce prerecorded tidal flow waveforms with a precision of 0.5% (full stroke), enabling the simulation of tidal and forced flow patterns. This linear pump can be connected to a series of copper lung volumes (range 50-300 mL) with known time constants, so that lung volumes can be reproduced with a precision of +/-1% at frequencies 10-120bpm. Five airflow resistors were built using sinter material. When assessed using flows 0-300 mL.s(-1) all resistors showed a quasilinear pressure/ flow relationship, with slopes 1.0-5.6 kPa.L(-1).s. These resistances could be reproduced with a precision of +/-2.5%. The infant lung model can also be used to assess frequency responses of infant lung function equipment, since the pump is capable of delivering low amplitude volumes up to 20 Hz in a pseudorandom noise manner. In summary, based on error estimations, this infant lung model is able to test whether or not infant lung function equipment meets the requirements suggested by the European Respiratory Society-American Thoracic Society standardization group, that is: flow measurements within +/-2.5%, volume and resistance measurements within +/-5%, frequency response: magnitude attenuation <+/-10% and phase shift <+/-3 degrees at 10 Hz.
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PMID:The infant lung function model: a mechanical analogue to test infant lung function equipment. 1140 Oct 74

Ischemia is associated with the pathological changes caused by the accumulation of reactive oxygen metabolites (ROM) in cerebrovascular accident (CVA). The aim of this study was to determine red cell copper/zinc-superoxide dismutase (Cu/Zn-SOD) and catalase activities and copper and zinc concentrations both in plasma and in red cells in CVA. Cu/Zn-SOD and catalase activities of 16 patients, with an average age of 64 yr, were measured spectrophotometrically; copper and zinc concentrations were determined by atomic absorption spectrophotometer. The results showed that Cu/Zn-SOD activity was increased markedly in patients compared to the young controls and reached a peak on the d 5 of the disease, whereas the catalase activity of the patients on d 3 and d 5 were in the normal range, but higher on d 10. The enzyme activities of the elderly group were generally increased compared to the young controls. Copper and zinc concentrations showed corresponding alterations. These findings suggested that the effects of oxidative stress in CVA might be reflected in red cell and plasma parameters.
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PMID:Antioxidant status in cerebrovascular accident. 1143 77


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