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)

Postpneumonectomy paraplegia developed in a woman admitted for resection of bronchogenic carcinoma. Postpneumonectomy paraplegia is an uncommon, but catastrophic, event that is thought to be caused primarily by ischemia to the spinal cord; in this instance an epidural hematoma was the cause. Recommendations for prevention are presented.
 ...
PMID:Epidural hematoma as a cause of postpneumonectomy paraplegia. 397 74

Several drugs that inhibit the effects of serotonin may reduce or prevent experimental CNS ischemic damage, but these drugs are not approved for human use in the United States. Administration of cyproheptadine (which is available for clinical use) 15 minutes before or 5 minutes after the onset increased the duration of experimental rabbit spinal cord ischemia required to produce irreversible paraplegia. Drugs thought to be serotonin agonists did not aggravate the damage, but bufotenin reversed protective effect of cyproheptadine. The results suggest that serotonin antagonists reduce ischemic CNS damage; cyproheptadine may be a potential treatment for ischemic stroke.
 ...
PMID:Cyproheptadine reduces or prevents ischemic central nervous system damage. 398 50

The effectiveness of various sized shunts placed between the ascending and the descending aorta to prevent paraplegia in dogs with the thoracic aorta cross-clamped for 1 hour was tested. Three tapered shunts sizes were used with tip dimensions of 3.8, 5.2, and 6.3 mm inner diameter, with cross-sectional areas of 11.34, 21.23, and 33.18 mm2, respectively, and with an equal midportion diameter of 10 mm (3/8 inch). These shunts carried 40%, 60%, and 72% respectively, of baseline descending aortic flow during the cross-clamping period. Flow distribution was measured with radioactive microspheres in the spinal cord (gray and white matter) and kidneys. All dogs without shunts (Group I) developed paraplegia, severe proximal circulatory embarrassment, and severe ischemia of the spinal cord (mainly gray matter) that was followed by marked hyperemia persisting up to 24 hours following the experiment. Mortality was 33%. Only animals treated with large shunts (Groups III and IV) avoided paraplegia and postischemic injury. An effective shunt was characterized as carrying 60% or more of baseline descending aortic flow, having a cross-sectional area at its tip equal to or larger than 29% of the descending aorta, and equaling at least 54% of its diameter. Porportionately, the size of the tridodecylmethylamonium-heparin shunts being used in human beings (even the largest 9 mm inner diameter) is significantly inadequate to maintain distal flows and pressures for the prevention of spinal cord injury. Four clinical options are discussed.
 ...
PMID:Adequacy of ascending aorta-descending aorta shunt during cross-clamping of the thoracic aorta for prevention of spinal cord injury. 401 Mar 14

Paraplegia has been a devastating and unpredictable complication following surgical procedures necessitating temporary occlusion of the thoracic aorta. This study was undertaken to investigate the effect of the pressure gradient between the aortic pressure distal to the occlusion and cerebrospinal fluid pressure (CSFP), defined as "Relative spinal cord perfusion pressure" (RSPP) on the development of ischemia to the spinal cord by using somatosensory evoked potentials (SEP). In 30 mongrel dogs, the thoracic aorta just distal to the left subclavian artery was occluded for either 30 or 120 minutes until SEP disappeared. RSPP was maintained at 20, 30 or 40 mmHg in each dog by adjusting the degree of occlusion of th aorta and/or changing CSFP by withdrawal of cerebrospinal fluid or injection of normal saline into the subarachnoid space. SEP were recorded as a cortical response to the electrical stimulation of bilateral peroneal nerves. SEP did not disappear for 30 or 120 minutes when RSPP was 40 mmHg. It would be concluded that 40 mmHg or higher of RSPP is necessary in order to prevent the spinal cord ischemia due to the temporary occlusion of the thoracic aorta.
 ...
PMID:[Prevention of spinal cord ischemia after thoracic aortic occlusion]. 402 93

A 13-year-old girl with meningomyelocele and a cauda-equina-paraplegia-syndrome, with resulting long-standing ileus, developed an extensive gangrene of the stomach, the small bowel and parts of the colon. As pathogenesis a non-occlusive-ischemia is suspected; the exceptional neurological situation is discussed.
 ...
PMID:[Gangrene of the intestine with pneumatosis intestinalis in a child with meningomyelocele]. 408 86

Somatosensory evoked potentials (SEPs) from peroneal nerve were recorded continuously on 13 patients undergoing extensive aortic replacement of thoracic, abdominal, or thoracico-abdominal aneurysms. During this surgical procedure, the descending aorta is completely occluded, and circulation to the spinal cord may thus be compromised, causing a risk of postoperative paraplegia. This risk may be minimized if changes in the SEP seen during intraoperative monitoring prove to correlate well with clinical outcome. Changes in the SEP observed during complete occlusion of the aorta and subsequent restoration of blood flow included: (1) progressive latency prolongation within the first 10 min of occlusion, (2) coincident and progressive amplitude depression, (3) eventual loss of the SEP, (4) rapid reversal of these changes with restoration of circulation, and (5) preservation of the lumbar response when the cephalic response became abnormal. The degree of prolongation of latency after restoration of blood flow appeared related to the duration of aortic occlusion and to the duration of SEP absence. These findings indicate that conduction through the spinal pathways that mediate the SEP is sensitive to ischemia produced by aortic occlusion. Intraoperative monitoring of SEPs as a means of reducing the neurological morbidity of extensive aortic replacement is discussed.
 ...
PMID:Somatosensory evoked potentials during reversible spinal cord ischemia in man. 620 37

A 20 year (1963 to 1982) surgical experience including 175 consecutive patients with aortic dissections was analyzed by logistic discriminant analyses to identify predictors of high operative risk. The patient population had characteristics similar to those in large autopsy series. Sixty-nine percent had type A and 58% had acute dissections. The intimal tear was located in the ascending aorta in 60% of the patients, the descending aorta in 27%, and the transverse arch in 13%. The overall operative mortality rate was 23 +/- 3%. The operative mortality rates were substantially lower between 1977 and 1982: mortality in patients with acute type A dissections, 7 +/- 5%; in those with chronic type A, 11 +/- 7%; in those with acute type B, 13 +/- 12%; and in those with chronic type B, 11 +/- 11%. After preliminary univariate screening, the following factors were determined to be significant independent predictors of operative mortality (in rank order of declining predictive power): type A patients (n = 121), renal dysfunction, tamponade, renal/visceral ischemia, and operative date; type B patients (n = 54), rupture, renal/visceral ischemia, and age; all patients (n = 175), renal dysfunction, renal/visceral ischemia, site of tear (ascending less than descending less than arch), tamponade, operative date, and pulmonary disease. Interestingly, several variables had no important bearing on operative mortality, including type (acute vs chronic) of dissection, age, previous operation, rupture, stroke, paraplegia, Marfan's syndrome, concomitant aortic valve replacement and/or coronary artery bypass grafting, site of tear, and whether or not the tear was resected in type A patients; emergency operation, hypertension, previous cardiac symptoms, paraplegia, site of tear, and resection of tear in type B patients; and, when all patients were considered together, age, sex, cardiac symptoms, prior operation, stroke, paraplegia, acute myocardial infarction, acute aortic regurgitation, Marfan's syndrome, and tear resection. These data allow calculation of any individual patient's operative risk and document that the operative mortality rate today is relatively low for all patients with aortic dissections, irrespective of type or acuity. Earlier surgical referral of patients with acute type A or acute type B dissection before irreversible major end-organ ischemia and/or infarction is probably in part responsible for the substantially improved results since 1977.
 ...
PMID:Independent determinants of operative mortality for patients with aortic dissections. 623 61

Prior to proximal aortic cross-clamping, baseline measurements of spinal cord blood flow and function were done. Blood flow was evaluated with radioactive microspheres and function determined by assessment of somatosensory evoked potential (SEP). Group 1 (N = 6) animals had aortic cross-clamping for 5 minutes after ischemic spinal cord dysfunction (SEP loss) was documented. Group 2 (N = 9) underwent aortic cross-clamping for 10 minutes after loss of SEP. Group 3 (N = 6) also underwent 10 minutes of cross-clamping after initial SEP loss, but were treated intravenously with methylprednisolone (30 mg per kilogram of body weight) 10 minutes prior to cross-clamping and again 4 hours postoperatively. After release of the cross-clamp, the animals were allowed to recover and serial evaluations of spinal cord blood flow and neurological status were carried out for seven days. Group 1 animals recovered uneventfully without evidence of neurological injury. Group 2 animals sustained a 67% incidence of permanent spastic paraplegia (p = 0.02 versus Group 1). In contrast, methylprednisolone-treated animals sustained no clinically detectable neurological injury (p = 0.02 versus Group 2). Measurements of spinal cord blood flow at the time of SEP loss revealed similar degrees of spinal cord ischemia in all groups. No significant differences were observed in the duration of aortic cross-clamping prior to SEP loss among the three groups. The data indicate that short periods of cross-clamping (5 minutes) following SEP loss are well tolerated, whereas longer periods (10 minutes) are associated with a high incidence of paraplegia.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Prevention of ischemic spinal cord injury following aortic cross-clamping: use of corticosteroids. 649 78

Referring to the experimental study on acute spinal cord injury, it is known that gray matter falls into an ischemia after injury, but opinions have not been unanimous whether or not the white matter falls into ischemia or hyperemia. The blood flow through the white matter varies according to the severity of the injury and degree of resultant paraplegia. Using rabbits, the authors carried out a series of experimental acute spinal cord impaction injury giving impactions at different strength stepwise, i.e., 400, 300, 200 and 100 gcf (g X cm X force) respectively at the 9th thoracic level of the spinal cord. Thus, upon observation of the paralysed levels and measurement of variable spinal cord blood flows according to the hydrogen clearance method, it was concluded as follows: In the 400 and 300 gcf impaction groups a complete paraplegia was observed with a decrease of spinal cord blood flow both in the gray and white matters. In the 200 gcf group mainly incomplete paraplegia was occurred, and while gray matter showed ischemia, white matter showed indefinite response consisting of both ischemia and hyperemia. In the 100 gcf impaction group the gray matter fell into ischemia, but white matter showed a biphasic increase of blood flow. From the above results it was noted that upon impaction causing complete paraplegia spinal white matter shows ischemia and upon impaction giving transient paraplegia blood flow increases. Ischemia thus does not appear to be a common behavior of spinal cord blood flow spinal cord injury.
 ...
PMID:[Variations in spinal cord blood flow in stepwise spinal cord impaction injury]. 650 87

Occlusion of the abdominal aorta of the rabbit by inflating the balloon of a Swan-Ganz catheter positioned in the aorta is a simple and reliable method of producing spinal cord ischemia. The electrophysiological, neurological, and neuropathological correlates of ischemia with progressively longer durations and of ischemia after drug interventions were studied with the goal of developing an easily monitored, reproducible model for central nervous system ischemia. The percentage of animals developing paraplegia after varying periods of ischemia was zero after 15 minutes, 30% after 17 minutes, 33% after 20 minutes, 38% after 25 minutes, and 100% after 60 minutes of ischemia. After 25 minutes of ischemia the percentage of animals developing paraplegia was 87% when they were awake and not ventilated during ischemia and reperfusion, but dropped to 38% in animals that were paralyzed, sedated with ketamine, and ventilated, and when the metabolic acidosis that follows aortic occlusion was corrected during reperfusion. Pretreatment with thiopental, hypothermia, naloxone, methylprednisolone, and verapamil changed the percentage of animals developing paraplegia after 25 minutes of ischemia to 0%, 0%, 25%, 40%, and 100%, respectively. The component waves of the spinal somatosensory evoked potential (SSEP) disappeared sequentially during ischemia in the following order: P2, N4, N3, N2, and N1. After reperfusion, the SSEP components returned in reverse order of their disappearance. In the untreated animals, absence of the N3 wave for more than 10 minutes during ischemia was always followed by a neurological deficit. Pretreatment with thiopental or hypothermia permitted longer periods of electrophysiological silence without permanent neurological deficit. The ratio of the amplitude of N3 to N1 (N3/N1) was at least 70% of the control level, and N4 and P2 amplitudes were at least 30% of the control level at 120 minutes after reperfusion in all animals that had a normal outcome. Return of the N3/N1 amplitude to at least 90% of the control level or return of N3/N1 to 70% to 89% of control and P2 to at least 60% of control at 120 minutes after reperfusion reliably correlated with a normal 48-hour motor examination in animals with and without drug interventions.
 ...
PMID:Neurological outcome correlated with spinal evoked potentials in a spinal cord ischemia model. 670 48


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>