Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: UMLS:C0020672 (hypothermia)
17,327 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using an intramyocardial pH needle probe (21 gauge) to monitor myocardial metabolism during ischemia, we determined the effect of potassium cardioplegia at both moderate and deep hypothermia. Five groups of 5 dogs each were placed on cardiopulmonary bypass and the pH probe was inserted approximately 10 mm into the left ventricular free wall. Cardiac ischemia was achieved by cross-clamping the ascending aorta at 37 degrees C (Group 1), 27 degrees C (Group 2), or 17 degrees C (Group 3). In the remaining two groups, aortic cross-clamping was followed by the infusion of 600 to 800 ml of potassium cardioplegic solution adjusted to cardiac temperatures of 27 degrees C (Group 4) or 17 degrees C (Group 5). In each group, myocardial temperature was maintained constant, electrical and mechanical activity observed, and pH recorded until a plateau was reached or for 3 hours. Our results show a progressive and significant decrease in the metabolic rate with reduction in temperature over the 37 degrees to 17 degrees C range. By abolishing contractile activity, potassium cardioplegia markedly reduces the rate of hydrogen ion accumulation at 27 degrees C, but at 17 degrees C the additive effect of cardioplegia is much less pronounced. These observations support the principle of reducing contractile activity to a minimum during elective arrest of the heart but indicate that potassium cardioplegia does little to further reduce the rate of anaerobic metabolism, as shown by the measurement of intramyocardial pH, under conditions of deep hypothermia.
...
PMID:Intramyocardial pH during elective arrest of the heart: relative effects of hypothermia versus potassium cardioplegia on anaerobic metabolism. 2665 50

We sought to determine the relative protective effects of an intracellular-like, calcium-bearing, crystalloid solution (ICS) and a calcium-free, extracellular-like solution (ECS). Both solutions were similar in concentrations of potassium ions (25 to 26 mEq/L), in pH (7.7 to 7.8), and in osmolarity (340 to 360 mOsm/L). Normothermia was used to obviate masking the true effects of the solutions with the independent effects of hypothermia. Fifty-seven dogs were placed on cardiopulmonary bypass and had global myocardial ischemia for one hour. Continuous infusions and bolus injections into the aortic root of control solutions (n = 24), ECS (n = 15), and ICS (n = 16) were used. Two-hour postischemic ventricular performance was superior for ICS in comparison with ECS or control solutions regardless of administration mode. The multidose mode gave improved results with control and ECS groups. The use of an ICS yields improved postischemic performance in normothermic dog hearts.
...
PMID:An intracellular-like cardioplegic solution. Its enhancement of myocardial protection. 743 27

The efficacy of benidipine hydrochloride in preventing myocardial ischemia and reperfusion injury was evaluated in isolated rabbit hearts (n = 28). Isovolumic left ventricular function, coronary flow, creatine phosphokinase (CPK) release, and myocardial water content were measured after ischemia during both normothermia (37 degrees C; Group I) and hypothermia (23 degrees C; Group II). After baseline measurements, hearts were induced to arrest by chilled cardioplegic solution. Each group was divided into two subgroups, depending upon whether benidipine hydrochloride (10(-9) mole/liter) was added in the cardioplegia (A, without benidipine; B, with benidipine). After 30 min of ischemia for Group I and 180 min for Group II (which added another cardioplegia every 30 min), hearts were reperfused. Measurements the same as those at baseline were carried out every 15 or 30 min for up to 60 min. Benidipine-treated hearts started beating in a shorter time than did control hearts (Group I-B, 38.7 +/- 3.7 sec vs Group I-A, 59.9 +/- 5.6; Group II-B, 36.7 +/- 2.0 vs Group II-A, 47.8 +/- 3.3). The percentage of recovery of left ventricular developed pressure after 60 min of reperfusion was significantly better in benidipine groups (P < 0.05). With respect to changes in coronary flow and CPK release after reperfusion, benidipine groups were preserved extremely well. We conclude that the addition of benidipine hydrochloride to cardioplegic solution significantly improves ventricular function after myocardial ischemia and reperfusion.
...
PMID:Efficacy of benidipine hydrochloride on myocardial ischemia and reperfusion. 764 89

We investigated the whole body oxygen consumption (VO2) and the hemodynamic changes during the intraperitoneal hyperthermic perfusion (IPHP), which was coupled with induced hypothermia to prevent the cerebral disorder. IPHP was carried out for 90-120 min with 45-47 degrees C perfusate after the operation. We induced hypothermia using the surface cooling method and the infusion of triflupromazin. In no patient, the pulmonary artery temperature (PAT) rose above 40 degrees C. In the IPHP, there was a significant correlation between VO2 and PAT. If PAT reached 42 degrees C during the IPHP, VO2 would increase to 130-140% of the value at 37-38 degrees C. This rise is smaller than that during the total body hyperthermia (TBH), in which VO2 at 42 degrees C reached 130-190% of the value at 38 degrees C. Heart rate increased in proportion to the rising rate of body temperature. During the IPHP, PAT sometimes rose remarkably about 8 degrees C (from 32 degrees C to 40 degrees C) with a marked rise in heart rate. This rising rate of PAT is greater than that of TBH, in which PAT rose about 4-5 degrees C (from 37-38 degrees C to 42 degrees C). We consider that IPHP is not applicable to the patients with ischemic heart disease. During the rise of PAT, other circulatory parameters related to IPHP, changed in the same direction as those related to TBH. The rate of change of these parameters related to IPHP was smaller than that of the TBH, because during the IPHP the highest PAT was lower than that during TBH.
...
PMID:[The hemodynamic changes during the intraperitoneal hyperthermic perfusion under induced hypothermia]. 786 1

Core body temperature is normally rigidly regulated by effective thermoregulatory responses that are triggered by small deviations in core and skin temperature. All general anesthetics so far tested markedly impair thermoregulatory control, increasing the range of temperatures not triggering protective responses by approximately 20-fold. Inhibition of thermoregulatory control--and reemergence of protective responses--are major factors influencing intraoperative temperature. Mild hypothermia provides dramatic protection against cerebral ischemia and therefore is frequently indicated during neurosurgery. Hypothermia to core temperatures near 34 degrees C can usually be instituted passively so long as thermoregulatory vasoconstriction is inhibited by sufficient anesthesia or neurosurgery per se. When core temperature must be rapidly reduced, or reduced to values approaching 32 degrees C, active cooling will usually be needed. Forced air appears to be the most effective clinically practical cooling method. Mild hypothermia is also associated with serious complications including myocardial ischemia, impaired resistance to surgical wound infections, coagulopathies, and postoperative shivering. Consequently, patients deliberately made hypothermic during neurosurgery should subsequently be actively rewarmed.
...
PMID:Deliberate mild hypothermia. 788 Dec 39

The proinflammatory cytokines have been implicated in mediating myocardial dysfunction associated with myocardial infarction, severe congestive heart failure, and sepsis. We tested the hypothesis that cytokine levels are elevated after uncomplicated coronary artery bypass grafting and associated with episodes of postoperative myocardial ischemia and dysfunction. Coronary artery bypass grafting was performed under general anesthesia with moderate systemic hypothermia and cold-blood potassium cardioplegic solution. Tumor necrosis factor-alpha and interleukin-6 levels were determined by bioassays, and interleukin-8 levels were measured by a sandwich enzyme-linked immunosorbent assay. Myocardial function and ischemic episodes were assessed by intraoperative transesophageal echocardiography and perioperative 12-channel Holter monitoring. A total of 22 patients were studied, with no deaths or complications. Arterial tumor necrosis factor-alpha rose in a bimodal distribution, peaking at 2 and 18 to 24 hours after the operation (at 20.2 +/- 6.4 pg/ml, [mean +/- standard error of the mean]) and 5.8 +/- 1.6 pg/ml, respectively; before cardiopulmonary bypass: 0.90 +/- 0.20 pg/ml, p < 0.001 for both peaks) then progressively declined to levels before bypass. Arterial interleukin-6 was maximally elevated immediately on termination of cardiopulmonary bypass and peaked again 12 to 18 hours after cardiopulmonary bypass (at 7520 +/- 2439 pg/ml and 6216 +/- 1928 pg/ml, respectively; before bypass: 746 +/- 187 pg/ml, p < 0.0001 for both peaks). Arterial interleukin-8 levels were more variable but followed a similar pattern, peaking in the early period after cardiopulmonary bypass and again at 16 to 18 hours after the operation (at 4110 +/- 1403 pg/ml and 1760 +/- 1145 pg/ml, respectively; before bypass: 461 +/- 158, p < 0.05 for both peaks). By multivariate analysis, the aortic crossclamp time was independently predictive of postoperative cytokine levels. Left ventricular wall motion abnormalities were associated with both interleukin-6 and interleukin-8 levels, worsening scores being associated with increasing levels (for interleukin-6, p = 0.003; for interleukin-8, p = 0.05). Postoperative myocardial ischemic episodes were associated with interleukin-6 levels, six of seven (85%) patients with episodes of myocardial ischemia after a peak in interleukin-6 concentrations (p < 0.01). We conclude that proinflammatory cytokines are elevated after uncomplicated coronary revascularization and may contribute to postoperative myocardial ischemia and segmental wall motion abnormalities.
...
PMID:Relationship of the proinflammatory cytokines to myocardial ischemia and dysfunction after uncomplicated coronary revascularization. 793 95

Normothermic blood cardioplegia was developed originally to be used during cardioplegic induction and reperfusion as an adjunct for enhancing metabolic reversal of biochemical alterations occurring before, during, and after total myocardial ischemia. This adjunct was introduced clinically after extensive experimental testing. By contrast, continuous normothermic blood cardioplegia without hypothermia was introduced clinically without a scientific infrastructure and has generated great interest because of its simplicity and encouraging early results, but has caused substantial confusion. This report is written to (1) clarify the role of normothermic blood cardioplegia as an adjunct to available hypothermic and antegrade and retrograde methods of myocardial protection, rather than as an alternative to them, (2) call attention to the misconception that continuous coronary perfusion avoids ischemia inasmuch as "unintentional ischemia" may occur despite continuous coronary perfusion, (3) identify theoretic and practical limitations of warm continuous retrograde blood cardioplegia exposed by testing after its clinical introduction, (4) enumerate the unanswered questions posed after clinical use of this method, and (5) focus on the self-imposed inflexibility created by adoption of adversarial positions in regard to cardioprotective strategies that impedes our ability to combine, rationally, the spectrum of approaches to myocardial protection that have evolved from the recognized limitations of individual methods.
...
PMID:Normothermic blood cardioplegia. Alternative or adjunct? 812 15

To evaluate the behavior of circulating endothelin and atrial natriuretic peptide (ANP) during coronary artery bypass graft (CABG) surgery, blood samples from patients with coronary artery disease (n = 8) were investigated before, during and after operation. Plasma levels of endothelin and ANP were determined using the radioimmunoassay method. Baseline plasma levels were compared to those of normal volunteers (n = 6). Left ventricular function at rest and as a response to isometric exercise was evaluated using radionuclide ventriculography before and after coronary bypass surgery. The mean endothelin value was found to be within normal limits, however the mean ANP value was slightly higher than control. Patients had significantly improved left ventricular systolic and diastolic function after surgery. The mean endothelin level was higher than initial values immediately after extra-corporeal circulation and returned to initial values in two hours. However, ANP values were increased and remained higher than initial values. Baseline endothelin values were negatively correlated with systolic function parameters, whereas endothelin and heart rate had a positive correlation before extra-corporeal circulation. Coronary artery bypass graft surgery may cause an increase in the circulating endothelin level either due to endothelial injury or due to myocardial ischemia and hypothermia. Following surgery, increased endothelin levels returned to normal values immediately.
...
PMID:Changes in the circulating endothelin and atrial natriuretic peptide levels during coronary artery bypass surgery. 816 37

One hundred seven patients undergoing coronary artery bypass grafting were randomized to receive warm antegrade (n = 21), warm retrograde (n = 22), cold antegrade (n = 20), cold retrograde (n = 22), or intermittent cold antegrade (n = 22) blood cardioplegia. Myocardial oxygen consumption and lactate production, adenine nucleotides, and adenine nucleotide degradation products were measured during the operation, and creatine kinase-MB release was assessed postoperatively. Warm cardioplegia resulted in greater myocardial lactate production than cold cardioplegia (p = 0.048). Retrograde cardioplegia was associated with greater lactate production than antegrade cardioplegia (p = 0.015). Adenosine triphosphate depletion was similar among groups. However, poorly diffusible metabolites of adenosine triphosphate accumulated to the greatest extent in the intermittent cold group. Levels of hypoxanthine were highest after warm retrograde cardioplegia. Operative mortality and morbidity were low and were not different among groups. In summary, none of the five techniques of cardioplegia evaluated in this study was able to completely prevent myocardial ischemia. Anaerobic lactate production was minimized with cold cardioplegia and with antegrade cardioplegic delivery. Hypothermia may have impaired regeneration of adenosine triphosphate, however, particularly in association with inadequate or intermittent cardioplegic flow.
...
PMID:Which techniques of cardioplegia prevent ischemia? 823 94

Congenital fistula between a coronary artery and the left cardiac ventricle are extremely rare. Since Blakeway (1918) first described this type of anomaly, only 72 cases have been reported up to the present, within our knowledge. A surgical correction of congenital fistula of the right coronary artery to left ventricle in a 36 year-old woman who suffered from easy fatigability is reported. This lesion was deduced after echocardiography identified a dilated right coronary artery and fluttering of the posterior cusp of the mitral valve throughout the diastole, the diagnosis was confirmed by retrograde aortography and coronary angiography. The fistula was closed by Symbas's operation under cardiopulmonary bypass with cardiac arrest and mild hypothermia. Postoperative recovery was uneventful. Coronary angiography one month after the operation revealed that the right coronary artery was still dilated with thrombus; there were no signs of myocardial ischemia or infarction. This diagnosis and successful treatment were based on careful study of the documentation of the 72 previously reported cases.
...
PMID:[Symbas's operation in a case of congenital fistula of the right coronary artery to left ventricle]. 830 6


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

---