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)

A bioassay is described for the quantitation of tumor cells in blood specimens in a syngeneic mouse tumor system (Sarcoma 1 in A/J mice). The procedure involved i.m. injection of blood containing tumor cells into each thigh of normal recipient mice and, 14 days later, examination of the sites of injection for evidence of tumor growth. For each specimen, a tumor index was calculated based on the number of tumor takes and the size of the tumors. The number of tumor cells was determined by comparison with tumor indices from standard specimens with known number of tumor cells. Optimal conditions for this assay were investigated. We have used this bioassay to quantitate tumor cells in the venous blood of tumor-bearing animals under various treatments and manipulations. At the same time, the incidence of regional node metastasis was obtained by direct histological examination. Surgical removal of a well-established primary tumor enhanced the dissemination of the tumor, as evidenced by an increased incidence in regional node metastasis and an increase in the number of tumor cells reaching the venous circulation. Similar results were obtained when the tumor-bearing feet were ligated to produce ischemia of the primary tumor. Repeated physical trauma to the primary tumor resulted in increased dissemination of tumor cells into the venous circulation, but it did not increase the incidence of regional node metastasis. Immunosuppression of the tumor-bearing animals increased the dissemination of tumor cells, whereas immunostimulation decreased the dissemination.
 ...
PMID:Bioassay for quantitating circulating tumor cells in a syngeneic mouse tumor system. 126 58

We administered fructose-1,6-bisphosphate (FDP), 1 mM, to isolated and perfused rabbit hearts submitted, after 90 minutes of equilibration, to an ischemic period (60 minutes at a coronary flow of 0.17 ml/min/g), followed by a period of reperfusion (30 minutes at a coronary flow of 3.6 ml/min/g). FDP was delivered at different times following the experimental protocol: 60 minutes before ischemia and for the entire experiment; 60 minutes before and during ischemia, but not at reperfusion; at the onset of ischemia and during reperfusion; and only during reperfusion. The FDP cardioprotective effect was evaluated in terms of recovery of left ventricular pressure developed during reperfusion, creatine phosphokinase (CPK) and noradrenaline release, mitochondrial function (expressed as yield, RCI, QO2, ADP/O), ATP and creatine phosphate (CP) tissue contents, calcium homeostasis, and by measuring oxidative stress in terms of reduced and oxidized glutathione release and tissue contents. Our data show that the cytoprotective action of FDP is closely related to the time of administration. Optimal myocardial preservation was achieved when it was present prior to ischemia and during reperfusion. When given at the time of ischemia or only on reperfusion, FDP does not exert cardioprotection. The data suggest that the FDP cardioprotective effect is related to improvement of energy metabolism.
 ...
PMID:Role of timing of administration in the cardioprotective effect of fructose-1,6-bisphosphate. 163 29

In the course of the study of the syndrome of severe limb ischemia (SLI) in a representative clinical material of 300 patients and a number of experimental studies, we arrived to the proposal of this optimal methodical procedure for acute vascular closures of traumatic and non-traumatic origin in the limbs: a) In every injury and sudden pain with a change of the function of the limb, it is necessary to think of the SLI syndrome and to search targetedly for it. b) In injuries connected with bleeding our first-rate task is the control of this bleeding. For a temporary arrest of the bleeding it is necessary to prefer more physiological methods sparing collateral circulation to the still most used tourniquet. For this purpose a new device for temporary hemostasis called Hemostop has proved itself, designed by the author and attested both experimentally and clinically, protected as a Czechoslovak patent. From surgical measures have acquitted themselves from this viewpoint the insertion of vascular clamp, ligature of the vessel or its temporary cannulation. c) To set the diagnosis of SLI, it usually suffices a careful anamnesis and clinical examination, advantageous is the investigation by ultrasound. The angiography because of time consumption should be used only in indicated cases. d) The time factor--"race against the time"--has to be always borne on our mind. It is necessary to achieve the recovery of blood circulation in the limb up to 6 or at the latest up to 10 hours from the onset of injury or closure. e) For shortening of the period of tissue hypoxia it is of advantage to use the temporary cannulation of injured vessels. This should be used always, whenever because of any reasons, it is not possible to execute the final reconstructive operation up to 10 hours since the injury, e. g. in polytraumatism, transport difficulties and the like. f) In isolated vascular injuries without bleeding (about 45%) and in all non-traumatic SLI the patients must be efficiently heparinized (i. v. administration, at best by infusion) to prevent the growth of the distal thrombus. g) Final vascular reconstruction should be performed only by erudited surgeons, always with thromboctomy and in protected coagulum. Optimal reconstructive performance should be chosen: for embolism the thromboembolectomy, for acute thrombosis usually the bypassing the afflicted vascular portion by the graft, in injuries appears as the optimal reconstructive measure the anastomosis end to end. At the simultaneous or isolated lesion of the stem vein, we must always try to reconstruct it.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Severe limb ischemia syndrome. 175 12

Hydroperoxide-initiated chemiluminescence was standardized as a microassay to evaluate the occurrence of oxidative stress in human biopsies. Samples of 10 to 50 mg of rat liver or heart were homogenized, diluted in reaction medium, added with tert-butyl hydroperoxide, and assayed for chemiluminescence in a liquid scintillation counter in the out-of-coincidence mode. Optimal conditions for the assay were: 0.3 to 1.2 mg/mL of homogenate protein in 120 mM KCl, 30 mM phosphate buffer (pH 7.4), and 3 mM tert-butyl hydroperoxide at 30 degrees C. In these conditions, maximal chemiluminescence values were 550 +/- 30 and 1100 +/- 40 cps/mg protein, for liver and heart homogenates, respectively. Liver and heart homogenates were subjected to in vitro oxidative stresses such as supplementation with organic hydroperoxide or with enzymatic systems generating superoxide anion or hydrogen peroxide. Chemiluminescence was higher in the poststress samples than in the control ones. The ratio: poststress chemiluminescence/control chemiluminescence (B/A) was about 1.4 or higher for both tissues. Human heart biopsies were utilized to investigate the occurrence of oxidative stress after clinical situations associated to ischemia-reperfusion. B/A ratios were 2.1 +/- 0.4, 1.4 +/- 0.1, and 2.8 +/- 0.4 for human heart, liver, and skeletal muscle, respectively.
 ...
PMID:Hydroperoxide-initiated chemiluminescence: an assay for oxidative stress in biopsies of heart, liver, and muscle. 184 67

Clinical application of hypothermic pharmacologic cardioplegia in pediatric cardiac surgery is less than satisfactory, despite its well known benefits in adults. Protection of the ischemic immature rabbit heart with hypothermia alone is better than with hypothermic St. Thomas' II cardioplegic solution. Control of cellular calcium is a critical component of cardioplegic protection. We determined whether the existing calcium content of St. Thomas' II solution (1.2 mmol/L) is responsible for suboptimal protection of the ischemic immature rabbit heart. Modified hypothermic St. Thomas' II solutions (calcium content, 0 to 2.4 mmol/L) were compared with hypothermic Krebs bicarbonate buffer in protecting ischemic immature (7- to 10-day-old) hearts. Hearts (n = 6 per group) underwent aerobic "working" perfusion with Krebs buffer, and cardiac function was measured. The hearts were then arrested with a 3-minute infusion of either cold (14 degrees C) Krebs buffer (1.8 mmol calcium/L) as hypothermia alone or cold St. Thomas' II solution before 6 hours of hypothermic (14 degrees C) global ischemia. Hearts were reperfused, and postischemic enzyme leakage and recovery of function were measured. A bell-shaped dose-response profile for calcium was observed for recovery of aortic flow but not for creatine kinase leakage, with improved protection at lower calcium concentrations. Optimal myocardial protection occurred at a calcium content of 0.3 mmol/L, which was better than with hypothermia alone and standard St. Thomas' II solution. We conclude that the existing calcium content of St. Thomas' II solution is responsible, in part, for its damaging effect on the ischemic immature rabbit heart.
 ...
PMID:Calcium content of St. Thomas' II cardioplegic solution damages ischemic immature myocardium. 192 65

Vascular damage occurring in conjunction with orthopedic injury of the lower extremity is uncommon. This relative rarity is further complicated by the potentially subtle nature of vascular injury. Doppler signals and even palpable pulses do not exclude vascular damage. Missed or delayed diagnosis with a subsequent avoidable amputation is a too-frequent result. Displaced fractures of the distal femur and proximal tibia and particularly dislocation of the knee are associated with the highest risk of concomitant vascular injury and the poorest collateral circulation to support the distal limb. Optimal management of such injuries requires a high index of suspicion, aggressive use of angiography, and close cooperation among all members of the trauma team. With proper care, few extremities will be lost to ischemia alone. Limb loss should result only when the extremity has been too badly damaged to justify salvage efforts.
 ...
PMID:Vascular injury associated with fracture-dislocations of the lower extremity. 265 31

During percutaneous transluminal coronary angioplasty (PTCA) frontal ECG leads are routinely monitored. The detection of ST segment deviation during the procedure is important for decisions regarding guiding catheter seating and the timing of balloon inflation and deflation. ST segment deviation appears on intracoronary electrograms in the absence of changes on the surface ECG in many patients, while the reverse is true in some individuals. When a precordial lead is employed, V5 or V6 is most commonly selected. The surface ECG leads most sensitive for monitoring ischemia during left anterior descending angioplasty are not known. In nine lead surface ECGs recorded during balloon inflation, a small degree of ST segment elevation occurred in leads I, aVL, and V5. Lead V2 demonstrated an increase in ST displacement from 0.0 +/- 0.03 mV to 0.29 +/- 0.25 mV during coronary occlusion (p less than 0.01). We conclude that if V5 or V6 is used as a single precordial lead, surface ECG alterations are easily overlooked. During left anterior descending occlusion the most sensitive surface lead is V2. Optimal ECG monitoring during PTCA in some cases should involve surface lead V2 or the intracoronary lead.
 ...
PMID:Optimal ECG monitoring during percutaneous transluminal coronary angioplasty of the left anterior descending artery. 295 59

Optimal quantitation of myocardial infarction requires resolution of the three-dimensional geometry of the ischemic region at a time that progression of tissue necrosis has been completed and can be sharply delineated from noninfarcted myocardium but before significant remodeling of the ventricular chamber. Although this can be achieved at two to three days after coronary occlusion by histologic techniques, a variety of technologies including two-dimensional echo, CTT, SPECT, PET, and NMR have demonstrated potential for providing noninvasive quantitative measurements of the extent of myocardial infarction. Additional studies are needed to clarify the utility of these technologies for resolving the highly variable transmural distribution of infarction that is present in the clinical setting. Assessment of the region at risk for infarction, the ischemic zone, requires quantitative measurements of the degree of ischemia as well as the size of the ischemic region. Although the above technologies may provide quantitative measurements of the dimensions of the ischemic zone, the utility for resolving the highly variable transmural distribution of regional myocardial blood flow using clinically applicable methodologies has not been convincingly established at present. It is possible that cine CT, new generation PET, and NMR technologies may eventually provide noninvasive quantitative measurements of regional myocardial blood flow.
 ...
PMID:Myocardial infarction and risk region relationships: evaluation by direct and noninvasive methods. 327 60

Optimal methods of myocardial preservation in the neonate remain unknown. Hypothermia and cardioplegia have been shown to protect neonatal hearts, but few studies have examined the effects of cardioplegia when administered at normothermia. Accordingly, the role of 37 degrees C St. Thomas' cardioplegic solution in protecting the neonatal heart during 1 hour of ischemia in an isolated working rabbit heart model was examined. Both oxygenated and nonoxygenated cardioplegic solutions (CSs) were evaluated and compared with an oxygenated physiological saline solution (PSS). Following ischemia, control hearts were characterized by severely impaired left ventricular function, whereas all three treatment groups recovered well, indicating that the treatments provided substantial protection. Aortic flow recovered to 62, 63, and 57% of preischemic values for the oxygenated CS, nonoxygenated CS, and oxygenated PSS groups, respectively. Similarly, rate of change of pressure recovered to 76, 80, and 76% of preischemic values for oxygenated CS, nonoxygenated CS, and oxygenated PSS groups. All values were significantly greater than those for the control group. Recovery of developed pressure was significantly improved in all three groups. End-diastolic pressure rose markedly following ischemia in control hearts, was not increased after ischemia in hearts receiving oxygenated and nonoxygenated CS, but was increased in the oxygenated PSS group. These data indicate that crystalloid cardioplegia and oxygenated PSS provide substantial protection in neonatal rabbit hearts, even when delivered at 37 degrees C. No additional benefit was seen when the cardioplegic solution was oxygenated. Therefore, either method of balancing the oxygen supply/demand ratio appears to be beneficial: supplying oxygen intermittently during ischemia (oxygenated PSS group) or decreasing oxygen demand during the ischemic period (cardioplegia groups).
 ...
PMID:Protection of the neonatal heart following normothermic ischemia: a comparison of oxygenated saline and oxygenated versus nonoxygenated cardioplegia. 337 77

Long-term studies regarding the effect of treatment on prognosis are lacking, but the adverse implications suggested for silent ischemia support aggressive management. Treatment of silent ischemic episodes is possible utilizing a large variety of agents. Optimal detection and quantitation methods are still being developed, but guidelines for treatment should be similar to those for treatment of symptomatic ischemia.
 ...
PMID:Treatment of silent myocardial ischemia. 353 96


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