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)

Twenty-four pigs were studied to assess the effect of potassium in a cardioplegic solution on the ability of the swine myocardium to maintain functional and metabolic integrity following induced ischemia. The pigs were evaluated on total and right heart bypass with measurement at normothermia and after a one-hour intervention of stroke volume (SV), coronary blood flow (CBF), myocardial oxygen consumption (MVO2), and lactate extraction. Myocardial tissue gases (PmO2 and PmCO2) were continuously monitored and, at the conclusion of the procedure tissues were analyzed for adenosine triphosphate (ATP). There were five interventions: (1) hypothermic perfusion (28 degrees C) (Group 1); (2) hypothermic ischemia (28 degrees C) (Group 2); and hypothermic ischemia with a cardioplegic solution (nonlactated Ringer's solution, pH 7.4, 4 degrees C) using (3) normokalemia (4 mEq of potassium chloride/L, 300 mOsm/L (Group 3), (4) hyperkalemia (43 mEq of KCl/L, 390 mOsm/L) (Group 4), and (5) normokalemia with increased osmolarity (3.6 mEq of KCl/L, 400 mOsm/L) (Groups 5). A significant decrease in SV and elevation in peak PmCO2 were seen in all groups subjected to ischemia except those protected with hyperkalemic solution. We conclude that the presence of hyperkalemia in a cold root perfusion solution provides better myocardial protection than cold root perfusion alone. Furthermore, potassium arrest appears to be more protective than coronary perfusion at 28 degrees C.
Ann Thorac Surg 1979 Sep
PMID:The importance of hyperkalemia in a cold perfusion solution: a correlative study examining myocardial function, metabolism, tissue gases, and substrates. 48 29

1. The surface electromyogram (EMG) of human leg muscles was recorded during running at different speeds; The EMG was compared with the simultaneously recorded vertical force exerted by the foot and with the angle of the ankle joint. 2. During running, the electrical activity of the gastrocnemius muscle increased sharply 35--45 ms after ground contact and reached its maximum at the end of muscle stretch; This activity was superimposed on a slowly increasing level of activation, which began 120--180 ms before ground contact. At the end of the stance phase, gastrocnemius became inactive and, simultaneously, there was a sudden increase in tibialis anterior activity. The assumption that the steep increase in the gastrocnemius EMG reflects the spinal stretch reflex of alpha-motoneurons is supported by the following findings. 3. The peak level of gastrocnemius EMG in the stance phase of fast running was 2--3 times higher than the activity during maximum voluntary contraction. 4. With stimulation of the tibial nerve at different rates, the maximum isometric force was about 30--40% higher than the maximum voluntary isometric contraction. 5. The increase in EMG at 35--45 ms after ground contact was markedly diminished during running, after partial blockage of Ia afferents by ischemia, at a time when the strength of voluntary contraction was shown to be uninfluenced by the ischemia. 6. The gastrocnemius activity during running was simulated by electrical stimulation of the tibial nerve. The rate of stimulation was varied so as to approximate to the EMG profile during running. This indicated that a spinal stretch reflex could become mechanically effective within the shortest stance phase measured in a fast sprint (ca. 120 ms).
J Neurophysiol 1979 Sep
PMID:Neuronal mechanisms of human locomotion. 49 Jan 96

Failure of microvascular re-perfusion, no reflow, of the brain after a period of ischemia has been proposed as the etiology of the cerebral dysfunction frequently seen in patients after resuscitation from hemorrhagic shock. For this investigation rats were stressed by subjecting them to a period of combined hypoxia and hypotension followed by resuscitation. Micro-oxygen electrodes measured brain oxygen tension, thus allowing an assessment of the distribution of cerebral blood flow, during stress and after resuscitation. After resuscitation, a hyperemic response was noted, followed by gradual return of some areas of the brain to normal perfusion, while other areas remained hyperemic for at least 2 hours post-resuscitation. On the basis of these results there appears to be no support for the no-reflow hypothesis. These data imply that therapeutic modalities aimed at increasing cerebral blood flow and oxygenation in the post-resuscitation period are insufficient in themselves for improved survival of patients sustaining a hypotensive, hypoxic episode.
J Trauma 1979 Sep
PMID:Effects of hypoxia and hypotension on oxygen delivery in the brain. 49 Jul 43

7 patients with primary and 3 patients with secondary Raynaud's disease were studied by directional Doppler-ultrasound. Flow curves were registered of radial and ulnar artery in rest and during reactive hyperemia following ischemia and muscle work before and under medical treatment. Flow at rest and after provocation was much less than in normal persons. Effect of treatment could be demonstrated, so that this method seems to be very helpful in followup studies of patients with Raynaud's disease.
Med Klin 1979 Sep 28
PMID:[Functional diagnosis by directional doppler-ultrasound in patients with Raynaud's disease (author's transl)]. 49 57

The effects of single forearm arterial injuries with and without associated neurological injuries were studied. Fifty subjects were evaluated: seven patients with isolated arterial lacerations, 15 patients with isolated nerve lacerations, 13 patients with combined nerve and arterial injuries, and 15 control subjects. A series of noninvasive peripheral vascular studies were correlated with the symptoms produced by a controlled cold-environment exposure. The hemodynamic alterations associated with symptoms of hand ischemia, and particularly with cold intolerance, were studied. Unrepaired single arterial injuries caused modest, consistent alterations in hand vascularity, but few signs of ischemia or symptoms of cold intolerance. The remaining intact artery demonstrated a consistent increase in flow velocity. Combined nerve and artery injuries caused the most significant alterations in hand vascularity, and median nerve and associated artery injuries caused the most disabling symptoms. Single arterial lacerations had no effect on the rate or completeness of recovery from associated nerve injuries.
J Hand Surg Am 1979 Sep
PMID:Forearm arterial injuries. 50 Oct 48

The effects of l-penbutolol and dl-propranolol on A-V conduction, on excitability of ventricular muscle, and on ventricular tachycardia threshold in acute ischemia were compared, using anesthetized dogs. 1. L-penbutolol (100 microgram/Kg) and dl-propranolol (100 microgram/Kg) prolonged A-V conduction and reduced excitability of ventricular muscle significantly. L-penbutolol less prolonged A-V conduction than dl-propranolol. 2. Both l-penbutolol (50 microgram/Kg) and dl-propranolol (50 microgram/Kg) significantly prevented the lowering of ventricular tachycardia threshold in acute ischemia. These beta-blocking drugs are effective in the treatment of arrhythmia and l-penbutolol could be used safely, because of its weaker inhibition on A-V conduction.
Jpn Heart J 1979 Sep
PMID:Antiarrhythmic effects of L-penbutolol and DL-propranolol. Comparison of the effects of these two drugs on conductivity and excitability in canine heart in vivo. 50 26

Twenty-two cat hearts were perfused according to Langendorff technique and myocardial regional ischemia was induced by occlusion of left anterior coronary artery. Separation of particulate (bound) from soluble (free) fraction, and subsequent fractionation into plasma membranes, lysosomes, sarcoplasmic reticulum, and mitochondria were performed by sucrose density gradient ultracentrifugation. By ischemia for 60 min, particle-bound activity of cathepsin D decreased from 4.2 +/- 0.24 U/mg protein to 3.2 +/- 0.31 U/mg protein (p less than 0.01). Likewise, the particle-bound activity of beta-glucuronidase decreased from 11.9 +/- 0.92 U/mg protein to 6.2 +/- 1.28 U/mg protein (p less than 0.01). Accordingly, free/bound activity ratios of cathepsin D increased from 0.8 to 1.9 and beta-glucuronidase from 0.9 to 2.8, respectively. Conspicuous fall from 12.8 +/- 0.6 U/mg protein to 8.0 +/- 0.97 U/mg protein (p less than 0.01) in absolute specific activity of cathepsin D bound to the lysosomal fraction, presents definitive evidence of lysosomal release of the acid hydrolases during the early phase of myocardial ischemia. Electron microscopic observation of the ischemic myocytes revealed ultrastructural alterations of the lysosomes suggestive of autophagic degradation of various subcellular organelles.
Jpn Heart J 1979 Sep
PMID:Lysosomal hypothesis in evolution of myocardial infarction. Subcellular fractionation and electron microscopic cytochemical study. 50 30

Both crude and highly purified testicular hyaluronidase preparations have been shown to contain a component which increases the permeability of the microcirculation in rat skin. This permeability activity had an isoelectric point of 7.4 while hyaluronidase was 9.4. It also could be separated from hyaluronidase by acrylamide gel electrophoresis. The permeability factor was not inhibited by serum and may explain previous observations that hyaluronidase preparations decrease the ischemia and necrosis appropriate to experimental myocardial infarction in vivo.
Inflammation 1979 Sep
PMID:Permeability factor contaminating hyaluronidase preparations. 51 Dec 98

Skeletal muscle blood vessels from eight patients with documented Duchenne type muscular dystrophy were examined by light and electron microscopy, with particular attention to the capillary-venous bed. The characteristic lesions of vasoactive amine injury were not present. Endothelial degeneration and regeneration also were absent. Lamellation of capillary basement membranes was noted without true hypertrophy or evidence of discontunuities. Thrombus formation and platelet interaction were absent. Lumenal obliteration was not noted at the arterial level. Rarely, venous obliteration was present in association with nodular connective tissue overgrowth. The minimal abnormalities appear to be nonspecific and do not substantiate postulated vascular injury by vasoactive mediators or ischemia. The role of a nonspecific chronic inflammatory reaction with phagocytes derived from the vascular compartment should be considered with respect to those described basement membrane changes.
Neurology 1977 Sep
PMID:Blood vessel structure in Duchenne muscular dystrophy. I. Light and electron microscopic observations in resting muscle. 56 43

Intestinal volvulus may be the underlying process in patients presenting with intestinal ischemia. In 3 patients, angiographic findings of volvulus were erroneously interpreted as indicating occlusive or nonocclusive intestinal ischemia. In a fourth, the correct preoperative diagnosis was suggested by angiographic findings. Volvulus should be suspected at angiography by the whirlpool arrangement of the mesenteric arterial branches, the delayed filling and emptying of the arteries, and the intense opacification of the bowel wall. Familiarity with the angiographic picture of intestinal volvulus is essential for early diagnosis and for prompt initiation of appropriate therapy.
Radiology 1978 Sep
PMID:Intestinal volvulus: angiographic findings. 67 22


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