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

A simple implanted device was used to occlude acutely the left middle cerebral artery (MCA) of 16 conscious cats. Eight received no treatment and 8 were given intravenous mannitol (1.2 gm/kg) at the time of occlusion. The initial neurological findings in both groups were similar, that is, agitation, forced circling, and right hemiparesis. The treated cats remained alert but the untreated cats became lethargic and drowsy. Perfusion with a mixture of colloidal carbon and buffered paraformaldehyde was carried out from 30 minutes to 6 hours following MCA occlusion. Results of morphological examination of brains from the treated and untreated groups suggested that mannitol had a protective effect upon cerebral tissue during the primary phase of acute focal ischemia. Light microscopic analysis of neuronal alterations demonstrated considerable preservation of neurons in brains of treated cats. Beneficial effect of mannitol was attributed partly to prevention of capillary narrowing and suppression of ischemic cerebral edema.
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PMID:Modification of acute focal ischemia by treatment with mannitol. 62 43

There have been recent reports of rhabdomyolysis associated with cocaine abuse. The pathologic findings from these cases have not been described. Pathologic abnormalities in two fatalities with cocaine-associated rhabdomyolysis, including one with hyperpyrexia, acute renal failure, and disseminated intravascular coagulation, are discussed in detail. Skeletal muscle in both cases showed necrosis without evidence of vasculitis, polarizable foreign crystals, or other specific lesions. The individual with renal failure showed acute tubular necrosis with granular myoglobin casts in tubules. The mechanism of cocaine-associated rhabdomyolysis is unclear, but potentially includes ischemia due to vasoconstriction, direct toxicity, hyperpyrexia, and increased muscle activity from agitation or seizure. Adulterants may also play a role. In unexplained cases of rhabdomyolysis, toxicologic evidence of cocaine should be sought. In those cases of rhabdomyolysis associated with acute renal failure, the presence of cocaine in blood may be prolonged because of impaired renal clearance.
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PMID:Rhabdomyolysis associated with cocaine abuse. 174 98

Rhabomyolysis with myoglobinuria has been added relatively recently to the neurologic complications associated with the increased use of cocaine and the introduction of its alkaloid form (crack). This retrospective study reports our experience with 14 patients who presented with rhabdomyolysis after cocaine use in a municipal hospital over a 3-year period. Seven patients used "crack", 2 intravenous and 3 nasal insufflation. All patients but one had hyperthermia, 11 altered mental status, 8 tachycardia, and 4 muscle rigidity. Nine developed renal failure; 3 of these patients died. Two other patients died of cardiorespiratory arrest. Cocaine-related rhabdomyolysis has a high mortality. The observed association with hyperthermia and other central neurologic features resembles the neuroleptic malignant syndrome. Since chronic cocaine use may alter the availability of dopamine either through transmitter depletion or decrease in the number of dopamine receptors, a common pathogenetic mechanism is possible. However, other mechanisms, which are not mutually exclusive but rather frequently overlapping, may play an important role. These include agitation, hyperthermia, adrenergic overstimulation leading to vasoconstriction and ischemia or calcium release from the sarcoplasmic reticulum resulting in increased entry into the muscle cell leading to cell death; in addition, cocaine has direct toxic effect on the muscles.
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PMID:Rhabdomyolysis and hyperthermia after cocaine abuse: a variant of the neuroleptic malignant syndrome? 748 66

RheothRx Injection, an aqueous solution of a nonionic block copolymer (poloxamer 188) formulated for intravenous administration, was investigated as an inhibitor of red blood cell (RBC)-induced platelet aggregation at plasma concentrations of 0.05-5mgmL-1. Platelet aggregation was determined by measuring the fall in single platelet counts after mechanical agitation of 2mL aliquots of citrated whole blood in a 37 degrees C shaking waterbath. Inhibition of RBC-induced platelet aggregation of > 95% was observed for poloxamer 188 at a concentration of 1mgmL-1, and 41% inhibition was observed at 0.05mgmL-1. Poloxamer 188 was observed to be a more effective inhibitor of RBC-induced platelet aggregation than 2-chloradenosine (2-ClAd) or phosphoenolpyruvate/pyruvate kinase (PEP/PK). Studies using platelet rich plasma (PRP) showed that platelet aggregation could not be induced by shaking in the absence of RBC, though aggregation was induced by the addition of exogenous adenosine diphosphate (ADP). Poloxamer 188 did not inhibit ADP-induced platelet aggregation. We propose that poloxamer 188 protects RBC from mechanical trauma by non-specific adsorption of copolymer to the RBC surface (via the hydrophobic polyoxypropylene moiety), and that this effect prevents mechanical damage and hence leakage of ADP from RBC. RheothRx Injection has been shown to have value in the treatment of acute ischemic disorders such as myocardial infarction. The observation of significant inhibition of RBC-induced platelet aggregation at clinically relevant concentrations suggests that RheothRx Injection may have antithrombotic properties in vivo, and may therefore have potential not only in acute ischemia but also to prevent thrombosis within vascular prostheses or to prevent rethrombosis after angioplasty or endarterectomy.
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PMID:Inhibition of red blood cell-induced platelet aggregation in whole blood by a nonionic surfactant, poloxamer 188 (RheothRx injection). 750 70

The relation between hypoxia/ischemia and subsequent alterations in seizure susceptibility in developing brain remains unclear. We assessed the behavioral and electrocorticographic (ECoG) effects of hypoxic/ischemic brain damage on bicuculline (BIC)-induced seizures in 7-day postnatal rats, and determined maturational changes in seizure susceptibility, behavior and ECoG activity. Rat pups were subjected to unilateral common carotid artery ligation, followed by exposure to 8% O2 at 37 degrees C for 2 h, an insult that produces brain damage in the cerebral hemisphere ipsilateral to carotid artery occlusion. The experimental group consisted of rat pups previously subjected to hypoxia/ischemia; control littermates received neither arterial ligation nor systemic hypoxia. Experimental animals received 4, 5, or 6 mg/kg BIC subcutaneously (s.c.) at 2 and 24 h, and at 3, 7, and 21 days of recovery from hypoxia/ischemia. Two animals at each interval of recovery, 1 each from the experimental and control groups, were used for ECoG monitoring. After BIC injection, animal behavior was observed for 2 h. Behaviors and seizures were classified in five categories based on severity, duration, and character: 1, mild irritability; 2, few clonic seizures and agitation; 3, few tonic-clonic seizures with swimming movements; 4, frequent tonic-clonic seizures with apneic episodes; 5, continuous tonic-clonic seizures and death. Rat pups previously subjected to hypoxia/ischemia had lesser seizure susceptibility than controls at 2-h recovery (p < 0.05) and greater susceptibility than controls at 24 h (p < 0.05). Tonic seizures were prominent at 2 and 24 h in both the experimental and control groups, whereas lesion-sided circling was prominent only in the hypoxic/ischemic rat pups.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of hypoxia/ischemia on bicuculline-induced seizures in immature rats: behavioral and electrocortical phenomena. 760 19

We report the historical, clinical, and laboratory findings in 5 patients after crack cocaine ingestion. All patients exhibited adrenergic crisis as a result of their ingestion. Analysis of their history revealed a latency period before signs and symptoms occurred as well as a wide variation in the number of crack cocaine nuggets ingested. Signs of intoxication were hypertension, tachycardia, hyperthermia, agitation, and generalized seizure activity. Treatment included therapeutic sedation with lorazepam and adrenolysis with esmolol infusion. The majority of patients showed electrocardiographic evidence of cardiac ischemia, but not elevations in serum creatinine phosphokinase enzymes--MB fraction. One patient died of complications associated with subclinical status epilepticus. The toxicities of crack cocaine ingestion are seldom appreciated. Prompt reversal of both cardiovascular and neurological signs and symptoms with appropriate pharmacologic agents is indicated.
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PMID:Adrenergic crisis from crack cocaine ingestion: report of five cases. 759 78

The authors studied autopsy protocols, microscopic and histochemical data on the heart for miners who had died suddenly. No positive trend in the sudden coronary death incidence in miners was reported. A great number of sudden deaths were registered in mines. The deaths are attributed to severe atherosclerosis responsible for irreversible changes in the myocardium, coronary vascular spasms, emergence of pathological agitation triggering lethal ischemia.
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PMID:[Incidence and pathomorphological characteristics of the development of sudden coronary death in coal miners]. 830 94

To use cultured human hepatocytes as a hybrid artificial liver, effective methods for isolating and culturing the hepatocytes from resected surgical specimens were investigated. Two different procedures for isolating hepatocytes, perfusion and agitation with a collagenase solution (Method 1) and perfusion with a mixed solution of collagenase and dispase (Method 2), were examined. The yield of isolated hepatocytes obtained by Method 2 (13.31 x 10(6) cells/g of liver) was significantly higher than that by Method 1 (0.94 x 10(6)). The warm ischemia time (0-90 min) of the liver fragments obtained did not disturb the viability and yield of the isolated hepatocytes. The gluconeogenesis and urea synthesis of the cultured human hepatocytes were well preserved for 10 days. These results show that for prolonged human hepatocyte culture (10 days), isolation from resected human liver tissues by a combination of the proteolytic enzymes collagenase and dispase was effective and warm ischemia was tolerated for up to 90 min, which indicates the possibility of using cultured human hepatocytes as a hybrid artificial liver.
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PMID:Isolation and culture of human hepatocytes from resected liver tissue as a bioreactor for a hybrid artificial liver. 833 42

Adequate prehospital care of the severely traumatised patient is important to prevent or attenuate early as well as late life threatening complications, such as tissue hypoxia, ischemia/reperfusion injury and finally multiple organ failure. A mismatch of oxygen supply and oxygen demand is a hallmark in the pathophysiology of multiple trauma. Oxygen supply may be diminished by the following factors: shock-related decrease of cardiac output, anemia and hypoxia. On the other hand, oxygen demand may be increased by pain, panic, and agitation. Hence, it is a central point in prehospital care to reduce this supply-demand imbalance by identification and prompt reversal of the underlying causes. Most often, shock is caused by hypovolaemia and tissue injury ("traumatic-hemorrhagic shock"). However, shock may also be a result of central nervous system injury (neurogenic shock as a special form of distributive shock) or circulatory obstruction, e.g tension pneumothorax or cardiac tamponade (obstructive shock). Volume resuscitation by means of crystalloid or colloid solutions is an essential part in the therapy of the traumatic-haemorrhagic shock. In addition, catecholamines may be necessary in order to achieve an adequate arterial pressure. However, if bleeding cannot be controlled in the prehospital setting, only moderate volume support and permissive hypotension as well as rapid transportation into the next hospital may be preferable. This may be the case in penetrating thoracic or abdominal injuries as well as in traumatic amputations of the proximal limb. On the contrary, in patients with severe head injury, hypotension must be avoided by all means. Obstructive shock has to be treated urgently by insertion of a chest drain or drainage of the pericardium, respectively. Under all circumstances, it is an essential part of prehospital therapy to provide sufficient analgesia as soon as possible. Prehospital anesthesia, combined with artificial ventilation may be necessary for optimal patient management. Furthermore, ventilatory support is indicated when respiratory failure, loss of consciousness, or severe shock are present. Additional oxygen should be given whenever possible, even in the absence of an overt hypoxic state. Important additional measures are cervical spine immobilisation and reposition as well as splinting of long bone fractures or luxations, in order to avoid secondary injury of the spinal cord or ongoing tissue and vascular damage.
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PMID:[Emergency management of polytrauma patients]. 902 49

Recent clinical trials with non-competitive and competitive N-methyl-D-aspartate (NMDA) receptor antagonists in patients with stroke have shown that these patients develop more adverse effects, particularly psychomimetic effects such as hallucinations and agitation, than normal volunteers at equivalent doses. We therefore examined whether such increased adverse effect potential of NMDA antagonists also occurs in a rat model of permanent focal ischemia. For this purpose, the right middle cerebral artery was occluded under halothane anesthesia, and behavioral alterations in response to the non-competitive NMDA antagonist, MK-801 (dizocilpine), were recorded after recovery from anesthesia. Behavioral alterations in ischemic rats were compared with those in sham-lesioned rats in a blinded fashion. MK-801 (0.4 mg/kg) induced psychomimetic-like stereotyped behaviors which were about twice as intense in ischemic than in non-ischemic rats. A similar trend for enhanced adverse effects was seen with the competitive NMDA antagonist CGS 19755 (Selfotel). Although more NMDA antagonists have to be tested to draw definite conclusions, the present data may indicate that enhanced sensitivity of stroke patients to adverse effects of NMDA antagonists can be predicted by use of a focal ischemia model in rats, thus allowing use of this model for developing novel cytoprotective strategies targeted to minimize glutamatergic excitotoxicity with reduced adverse effect potential.
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PMID:Focal ischemia enhances the adverse effect potential of N-methyl-D-aspartate receptor antagonists in rats. 948 68


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