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)

We report a 12-year-old child with episodes of migraine-like headaches with visual and motor auras a year after the surgical resection and radiation therapy for medulloblastoma The patient presented with an episode of headache, prolonged aphasia, right hemiparesis, status epilepticus, and salt wasting. There was no evidence of a structural lesion. The neurologic deficits resolved over a period of 6 weeks. Because of the progressive deterioration in neurologic deficits, the patient underwent an extensive battery of laboratory tests and multiple neuroimages, all of which were normal. The unusually prolonged neurologic deficit in this patient without demonstrable structural lesions and his eventual complete recovery were most likely caused by ischemia in the left hemisphere secondary to vasospasm. This presentation mimics migraine headache. Evidence suggesting that this represents a long-term complication of treatment of children with central nervous system neoplasia is presented.
 ...
PMID:Pseudomigraine with prolonged aphasia in a child with cranial irradiation for medulloblastoma. 1195 86

Preconditioning a powerful protective mechanism, is the response to transient ischemia and reperfusion. However, the best way to achieve total protection is to avoid ischemia altogether. Therefore prevention of ischemia and protection by preconditioning are differently mediated so that anti-ischemic agents may not precondition, whereas paradoxically pro-ischemic agents may precondition. Metabolically active agents such as glucose-insulin-potassium, trimetazidine and ranolazine that protect from ischemia, increase glucose metabolism relative to that of fatty acids. By promoting glycolysis they tend to close the ATP-dependent potassium channels that help to mediate preconditioning. By lessening the oxygen-wasting effects of fatty acids, they are mitochondrial protective and oxygen-sparing. These qualities should help in the therapy of myocardial ischemia and also heart failure.
 ...
PMID:Preconditioning and metabolic anti-ischaemic agents. 1456 45

The primary effect of ischemia is reduced aerobic adenosine triphosphate (ATP) formation in mitochondria. This triggers accelerated glycolysis and reduced cell pH, Ca(2+) accumulation, K(+) efflux, adenosine formation, and the clinical signs of ischemia: chest pain and a shift in the ST segment. Traditional therapies for angina are aimed at either decreasing the need for ATP by suppressing heart rate, blood pressure, and cardiac contractility, or at increasing oxygen delivery to the mitochondria, or both. An additional approach to treating angina is to suppress myocardial fatty acid oxidation, increase pyruvate oxidation, and reduce anaerobic glycolysis. High fatty acid levels result in oxygen wasting and inhibit the oxidation of pyruvate in the mitochondria. In experimental models, the partial inhibition of myocardial fatty acid oxidation with agents such as oxfenicine, ranolazine, and trimetazidine stimulates glucose oxidation and reduces lactate production during ischemia. Clinical studies demonstrate that this approach is as effective as traditional hemodynamic therapies at improving exercise tolerance and reducing the frequency of angina. Moreover, because these agents do not suppress heart rate, blood pressure, or contractility, they are effective as add-on therapy to Ca(2+)-channel and beta-adrenergic receptor antagonists.
 ...
PMID:Myocardial energy metabolism during ischemia and the mechanisms of metabolic therapies. 1537 30

CryAB and HSPB2 are small heat shock proteins constitutively expressed in the heart. CryAB protects cytoskeletal organization and intermediate filament assembly; the functions of HSPB2 are unknown. The promoters of CryAB and HSPB2 share regulatory elements, making identifying their separate functions difficult. Here, using a genetic approach, we report distinct roles for these sHSPs, with CryAB protecting mechanical properties and HSPB2 protecting energy reserve. Isolated hearts of wild type mice (WT), mice lacking both sHSPs (DKO), WT mice overexpressing mouse CryAB protein (mCryAB(Tg)), and mice with no HSPB2 made by crossing DKO with mCryAB(Tg) (DKO/mCryAB(Tg)) were stressed with either ischemia/reperfusion or inotropic stimulation. Contractile performance and energetics were measured using 31P NMR spectroscopy. Ischemia/reperfusion caused severe diastolic dysfunction in DKO hearts. Recovery of [ATP] and [PCr] during reperfusion was impaired only in DKO/mCryAB(Tg). During inotropic stimulation, DKO/mCryAB(Tg) showed blunted systolic and diastolic function and revealed massive energy wasting on acute stress: |deltaG(-ATP)| decreased in DKO by 6.4 +/- 0.7 and in DKO/mCryAB(Tg) by 5.5 +/- 0.8 kJ/mol compared with only approximately 3.3 kJ/mol in WT and mCryAB(Tg). Thus, CryAB and HSPB2 proteins play nonredundant roles in the heart, CryAB in structural remodeling and HSPB2 in maintaining energetic balance.
 ...
PMID:Unmasking different mechanical and energetic roles for the small heat shock proteins CryAB and HSPB2 using genetically modified mouse hearts. 1784 79

This disease occurs in adolescence, predominatly in male. The main clinical features include predominantly unilateral muscular weakness and wasting of the hand and forearm (the brachioradialis is spared: oblique amyotrophy). The clinical course is incidious onset and slowly progressive, followed by a spontaneous arrest within several years. Twelve patients with this disease were first reported by Hirayama and his associates in 1959, who clinically distinguished this disorder from previously known degenerative and progressive motor neuron diseases. The clinical features had been further clarified by the report on 20 patients in 1963, and completed in the report on 38 patients in 1972. A quarter of a century had passed without pathological confirmation, primarily due to the benign course of the disease. The first autopsy case was obtained in 1982. The neuropathological findings were reported by Hirayama and his associates in 1985 in Japanese, then in 1987 in English. The spinal cord showed anteroposterior flattening and ischemic necrotic changes of the anterior horns of the cervical cord at C5-T1, mostly severe at C7 and C8, predominantly on the left (the patient had bilateral muscular atrophy, predominantly on the left). These findings suggested a circulatory insufficiency of the lower cerivical cord, but the intra- and extra-medullary vessels were normal. The pathologic evidence prompted neuroradiologic (CT, MRI) studies in the late 1980s. Our studies of 73 patients revealed that dynamic compression of the lower cervical cord due to forward displacement of the cervical dural sac (especially posterior segment) and spinal cord on neck flexion was confined to an early and progressive stage of the disease. An absence of forward displacement in a later and non-progressive stage of the disease suggested that the dynamic compression had pathogenic significance. The pathologic findings and results of radiological studies suggest that sustained or repeated neck flexion might cause an anterior shift of the cervical dural sac, then the compressed cervical cord at the segments induce an increased intramedullary pressure, resulting in microcirculatory disturbance in the anterior horn, the most vulnerable structure to ischemia in the spinal cord. Based on this hypothesis, we tried cervical collar therapy for patients when they may have sustained or repeated neck flexion, and reported these data in 1991, 1992 and 2001. No one showed further progression of signs and symptoms. This favorable effect supports our pathogenic hypothesis described above. The author proposes that the etiology of this disease is disproportionate growth between the vertebral column and the contents of the spinal canal especially the dural sac during the juvenile growth. The nationwide epidemiological study in Japan was carried out from 1996 to 1998, identified 333 cases of the disease. There were fewer case reports from other countries than from Japan. As the number of patients is exceedingly large in Japan, there might be an ethnic factor in this disorder.
 ...
PMID:[Juvenile muscular atrophy of unilateral upper extremity (Hirayama disease)--half-century progress and establishment since its discovery]. 1823 29

The mitochondrial F1F0 ATP synthase is responsible for the majority of ATP production in mammals and does this through a rotary catalytic mechanism. Studies show that the F1F0 ATP synthase can switch to an ATP hydrolase, and this occurs under conditions seen during myocardial ischemia. This ATP hydrolysis causes wasting of ATP that does not produce work. The degree of ATP inefficiently hydrolyzed during ischemia may be as high as 50-90% of the total. A naturally occurring, reversible inhibitor (IF-1) of the hydrolase activity is in the mitochondria, and it has a pH optimum of 6.8. Based on studies with the nonselective (inhibit both synthase and hydrolase activity) inhibitors aurovertin B and oligomycin B reduce the rate of ATP depletion during ischemia, showing that IF-1 does not completely block hydrolase activity. Oligomycin and aurovertin cannot be used for treating myocardial ischemia as they will reduce ATP production in healthy tissue. We generated a focused structure-activity relationship, and several compounds were identified that selectively inhibited the F1F0 ATP hydrolase activity while having no effect on synthase function. One compound, BMS-199264 had no effect on F1F0 ATP synthase function in submitochondrial particles while inhibiting hydrolase function, unlike oligomycin that inhibits both. BMS-199264 selectively inhibited ATP decline during ischemia while not affecting ATP production in normoxic and reperfused hearts. BMS-191264 also reduced cardiac necrosis and enhanced the recovery of contractile function following reperfusion. These data also suggest that the reversal of the synthase and hydrolase activities is not merely a chemical reaction run in reverse.
 ...
PMID:Pharmacological profile of the selective mitochondrial F1F0 ATP hydrolase inhibitor BMS-199264 in myocardial ischemia. 1903 80

In patients who undergo rehabilitation after ischemic stroke, nutrition strategies are adopted to provide tube-fed individuals with adequate nutrition and/or to avoid the body wasting responsible for poor functional outcome and prolonged stay in the hospital. Investigations have documented that nutrition interventions can enhance the recovery of neurocognitive function in individuals with ischemic stroke. Experimental studies have shown that protein synthesis is suppressed in the ischemic penumbra. In clinical studies on rehabilitation patients designed to study the effects of counteracting or limiting this reduction of protein synthesis by providing protein supplementation, patients receiving such supplementation had enhanced recovery of neurocognitive function. Cellular damage in cerebral ischemia is also partly caused by oxidative damage secondary to free radical formation and lipid peroxidation. Increased oxidative stress negatively affects a patient's life and functional prognosis. Some studies have documented that nutrition supplementation with B-group vitamins may mitigate oxidative damage after acute ischemic stroke. Experimental investigations have also shown that cerebral ischemia changes synaptic zinc release and that acute ischemia increases zinc release, aggravating neuronal injury. In clinical practice, patients with ischemic stroke were found to have a lower than recommended dietary intake of zinc. Patients in whom daily zinc intake was normalized had better recovery of neurological deficits than subjects given a placebo. The aim of this review is to highlight those brain metabolic alterations susceptible to nutrition correction in clinical practice. The mechanisms underlying the relationship between cerebral ischemia and nutrition metabolic conditions are discussed.
 ...
PMID:Nutrition for brain recovery after ischemic stroke: an added value to rehabilitation. 2158 19

Hypokalemia is common and can be associated with serious adverse consequences, including paralysis, ileus, cardiac arrhythmias, and death. As a result, the body maintains serum potassium concentration within very narrow limits by tightly regulated feedback and feed-forward systems. Whereas the consequences of symptomatic hypokalemia and severe potassium depletion are well appreciated, chronic mild hypokalemia can accelerate the progression of chronic kidney disease, exacerbate systemic hypertension, and increase mortality. Persistent hypokalemia may reflect total-body potassium depletion or increased renal potassium clearance. In a patient with simple potassium depletion, potassium replacement therapy should correct serum potassium concentration, but may have little effect when renal potassium clearance is abnormally increased from potassium wasting. In such cases, the addition of potassium-sparing diuretics might be helpful. Serum potassium concentration is an inaccurate marker of total-body potassium deficit. Mild hypokalemia may be associated with significant total-body potassium deficits and conversely, total-body potassium stores can be normal in patients with hypokalemia due to redistribution. The speed and extent of potassium replacement should be dictated by the clinical picture and guided by frequent reassessment of serum potassium concentration(.) The goals of therapy should be to correct a potassium deficit, if present, without provoking hyperkalemia. Oral replacement is preferred except when there is no functioning bowel or in the setting of electrocardiogram changes, neurologic symptoms, cardiac ischemia, or digitalis therapy.
 ...
PMID:A physiologic-based approach to the treatment of a patient with hypokalemia. 2290 31

The ubiquitin-proteasome system (UPS) plays a central role in maintaining protein homeostasis, emphasized by a myriad of diseases that are associated with altered UPS function such as cancer, muscle-wasting, and neurodegeneration. Protein ubiquitination plays a central role in both the promotion of proteasomal degradation as well as cellular signaling through regulation of the stability of transcription factors and other signaling molecules. Substrate-specificity is a critical regulatory step of ubiquitination and is mediated by ubiquitin ligases. Recent studies implicate ubiquitin ligases in multiple models of cardiac diseases such as cardiac hypertrophy, atrophy, and ischemia/reperfusion injury, both in a cardioprotective and maladaptive role. Therefore, identifying physiological substrates of cardiac ubiquitin ligases provides both mechanistic insights into heart disease as well as possible therapeutic targets. Current methods identifying substrates for ubiquitin ligases rely heavily upon non-physiologic in vitro methods, impeding the unbiased discovery of physiological substrates in relevant model systems. Here we describe a novel method for identifying ubiquitin ligase substrates utilizing tandem ubiquitin binding entities technology, two-dimensional differential in gel electrophoresis, and mass spectrometry, validated by the identification of both known and novel physiological substrates of the ubiquitin ligase MuRF1 in primary cardiomyocytes. This method can be applied to any ubiquitin ligase, both in normal and disease model systems, in order to identify relevant physiological substrates under various biological conditions, opening the door to a clearer mechanistic understanding of ubiquitin ligase function and broadening their potential as therapeutic targets.
...
PMID:Diggin' on u(biquitin): a novel method for the identification of physiological E3 ubiquitin ligase substrates. 2369 82

Kir4.1 is an inwardly rectifying K(+) channel expressed exclusively in glial cells in the central nervous system. In glia, Kir4.1 is implicated in several functions including extracellular K(+) homeostasis, maintenance of astrocyte resting membrane potential, cell volume regulation, and facilitation of glutamate uptake. Knockout of Kir4.1 in rodent models leads to severe neurological deficits, including ataxia, seizures, sensorineural deafness, and early postnatal death. Accumulating evidence indicates that Kir4.1 plays an integral role in the central nervous system, prompting many laboratories to study the potential role that Kir4.1 plays in human disease. In this article, we review the growing evidence implicating Kir4.1 in a wide array of neurological disease. Recent literature suggests Kir4.1 dysfunction facilitates neuronal hyperexcitability and may contribute to epilepsy. Genetic screens demonstrate that mutations of KCNJ10, the gene encoding Kir4.1, causes SeSAME/EAST syndrome, which is characterized by early onset seizures, compromised verbal and motor skills, profound cognitive deficits, and salt-wasting. KCNJ10 has also been linked to developmental disorders including autism. Cerebral trauma, ischemia, and inflammation are all associated with decreased astrocytic Kir4.1 current amplitude and astrocytic dysfunction. Additionally, neurodegenerative diseases such as Alzheimer disease and amyotrophic lateral sclerosis demonstrate loss of Kir4.1. This is particularly exciting in the context of Huntington disease, another neurodegenerative disorder in which restoration of Kir4.1 ameliorated motor deficits, decreased medium spiny neuron hyperexcitability, and extended survival in mouse models. Understanding the expression and regulation of Kir4.1 will be critical in determining if this channel can be exploited for therapeutic benefit.
 ...
PMID:The role of glial-specific Kir4.1 in normal and pathological states of the CNS. 2696 Dec 51


<< Previous 1 2 3 4 Next >>