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 28,634 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We investigated the effects of low temperatures down to approximately 5 degrees C on postcapillary resistance (Rv) and isogravimetric capillary pressure (Pci) in the isolated constant-flow-perfused cat hindlimb to see if a low-temperature-induced increase in Rv and decrease in Pci could lead to an increase in filtration pressure and edema formation. A low-viscosity perfusate (20% cat plasma, 80% albumin-electrolyte solution; viscosity approximately 1 cP) was used. Isoproterenol (10(-7) M) was added to vasodilate the limb and achieve normal microvascular permeability. Rv and Pci were estimated from the slope and zero-flow intercept, respectively, of the straight-line fit to the isogravimetric venous pressure vs. flow data. Rv and Pci were determined in each experiment at an initial 37 degrees C control, at a lowered temperature (30, 23, 15, or 5-10 degrees C), and then at 37 degrees C again. The ratio of Rv at the low temperatures relative to the initial 37 degrees C control increased almost linearly as temperature was reduced. The increase was 3.4 times control at the lowest temperature. Pci decreased significantly from control only in the lowest temperature group where the change was -5.4 mmHg. Analysis of our data with the low-viscosity perfusate shows that the limb can become edematous if temperature is lowered to approximately 5 degrees C unless venous pressure (Pv) is lowered to venous collapse and flow reduced to less than approximately 20 ml.min-1.100g-1.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of cold on microvascular fluid movement in the cat limb. 193 45

Isoproterenol is sometimes required for ventricular tachycardia (VT) induction. However, the role of beta-blockade for treatment of such VT has not been critically assessed. The use of beta-blockade was evaluated prospectively in 14 consecutive patients who required isoproterenol 2.4 +/- 1.3 (+/- S.D.) micrograms/min to induce sustained monomorphic VT (greater than 30 seconds, or requiring termination due to hemodynamic collapse) after a negative baseline study. The VT mechanisms were enhanced automaticity (group A, six patients), triggered automaticity (group B, three patients), and reentry (group C, five patients). Groups A and B had serial intravenous electropharmacologic tests with propranolol alone (0.2 mg/kg), verapamil alone (0.15 mg/kg), and propranolol plus verapamil, and group C had serial tests with propranolol alone, procainamide or quinidine (class Ia drug) alone, and propranolol plus a class Ia drug until VT could no longer be induced. All six patients in group A responded to propranolol alone. In group B, one patient responded to verapamil alone, and two patients responded to propranolol plus verapamil. In group C, three patients responded to propranolol alone, one patient responded to a class Ia drug alone, and one patient responded to propranolol plus a class Ia drug. During a follow-up of 7 to 37 (17.9 +/- 10.7) (+/- S.D.) months, VT has not recurred in any patient. Three patients treated initially with propranolol alone have required substitution of amiodarone due to refractory congestive heart failure. In patients requiring isoproterenol for VT induction, beta-blockade alone appears to be effective in preventing reinduction of VT caused by enhanced automaticity. A heterogeneous response occurs when the VT mechanisms are triggered automaticity or reentry.
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PMID:The role of beta-blockade therapy for ventricular tachycardia induced with isoproterenol: a prospective analysis. 197 77

The effects of acute beta 1-blockade on fetal cardiovascular reactions during asphyxia were evaluated in 11 exteriorized sheep fetuses. Gestational age was 110-142 days. Asphyxia was induced either by ventilating the mother with low oxygen gas mixture or by mechanical reduction of placental blood flow. During asphyxia all fetuses reacted to metoprolol injection with a decrease in heart rate, myocardial contractility, cardiac output and arterial blood pressure. Five experiments resulted in irreversible fetal cardiovascular collapse. Isoprenaline was given to the fetuses during hypoxia to test the ability to further increase heart rate and activate myocardial beta-adrenoceptors. In those experiments with fetal cardiovascular demise after metoprolol, the isoprenaline injection did not result in a significant tachycardia. The surviving fetuses could increase their heart rate as a sign of a capacity to further increase the sympatho-adrenergic drive.
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PMID:Acute blockade of beta 1-receptors in the asphyxiated sheep fetus. 282 Jan 93

1 A 21-year-old student ingested thirty ricin seeds in a suicidal attempt, some of which were masticated. Three hours later he developed severe diarrhoea with vomiting and abdominal cramps, followed by extracellular dehydration and circulatory collapse. 2 Biological changes included haemoconcentration. He recovered following symptomatic treatment by infusion of saline and glucose solutions. 3 Ricin was quantified by a radioimmunologic method using Iodine 125, and showed that only a small part of the ricin contained in the seeds was absorbed.
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PMID:Acute voluntary intoxication by ricin. 686 67

Factors that contribute to the lethality of amitriptyline overdosage were studied in cats. Amitriptyline (50 mg/kg) given i.p. to unanesthetized cats produced convulsions in all of the animals and death in five of six animals; pretreatment with diazepam (5 mg/kg) protected against the convulsions and death. Respiratory depression contributed to the mortality when amitriptyline was given i.v. in cats anesthetized with pentobarbital as indicated by the finding that artificial respiration delayed the time of death induced by a continuous i.v. infusion of the drug. The i.v. infusion of amitriptyline in pentobarbitalized cats under artificial respiration produced death due to cardiovascular collapse. The latter was characterized by hypotension, bradycardia, depression of myocardial contractile force, atrioventricular block, intraventricular conduction delay and cardiac arrhythmias. These effects appear to be due to a direct membrane (quindine-like) cardiotoxic action of amitriptyline. Dopamine and dobutamine were effective in protecting the animals against the acute cardiovascular collapse induced by amitriptyline. The protection was associated with a diminution of the hypotension, the negative inotropic and chronotropic actions and the incidence of atrioventricular block produced by the tricyclic antidepressant drug. The results suggest that the positive chronotropic, inotropic and dromotropic actions of the amines may all be contributory factors in their protection action. Isoproterenol and norepinephrine were less effective than the other two amines.
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PMID:Protective action of diazepam and of sympathomimetic amines against amitryptyline-induced toxicity. 709 63

A 21-year-old male presented to the trauma unit after he was stabbed once with a knife in the left anterior chest. The patient was awake and combative, very intoxicated, with a systolic blood pressure of 90 mmHg by palpation and a heart rate of 110 beats per min. Physical examination revealed distended neck veins, a single 1.5 cm stab wound to the left parasternal area at the third ICS (noted by clip on x-ray, Fig. 1), poorly auscultated heart sounds, and palpable femoral pulses that went away with inspiration. Chest radiograph (Fig. 1) showed a "pear-shaped" cardiac silhouette, though not markedly enlarged, and a significant left hemothorax. A diagnosis of acute pericardial tamponade was made, and the patient was taken immediately to the operating room for thoracotomy and successful repair of a stab wound of the right ventricle. Figure 2 (courtesy of Richard Wolfe, MD, Massachusetts General Hospital, Boston, MA) presents an example of an echocardiogram depicting a pericardial effusion. Pericardial fluid is imaged as a black (hypoechoic) crescent area separating the apex of the heart from the pericardium, seen as a white ring (arrow) at the inferior aspect of the scan. Tamponade is defined sonographically as the presence of both pericardial effusion (PE) and diastolic collapse of the right ventricle. Figure 3 (courtesy of Michael H. Picard, MD, of Harvard Medical School, Boston, MA) demonstrates the collapse of the right ventricular outflow track (RVOT) and its position relative to the left ventricle (LV), the left atrium (LA), and the aortic valve (AV).
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PMID:Stab wound to the chest with acute pericardial tamponade. 896 98

An important consideration for clinical application of rotary blood pump based ventricular assist is the avoidance of ventricular collapse due to excessive operating speed. Because healthy animals do not typically demonstrate this phenomenon, it is difficult to evaluate control algorithms for avoiding suction in vivo. An acute hemodynamic study was thus conducted to determine the conditions under which suction could be induced. A 70 kg calf was implanted with an axial flow assist device (Nimbus/UoP IVAS; Nimbus Inc., Rancho Cordova, CA) cannulated from the left ventricular apex to ascending aorta. On initiation of pump operation, several vasoactive interventions were performed to alter preload, afterload, and contractility of the left ventricle. Initially, dobutamine increased contractility and heart rate ([HR] = 139; baseline = 70), but ventricular collapse was not achievable, even at the maximal pump speed of 15,000 rpm. Norepinephrine decreased HR (HR = 60), increased contractility, and increased systemic vascular resistance ([SVR] = 24; baseline = 15), resulting in ventricular collapse at a pump speed of 14,000 rpm. Isoproterenol (beta agonist) increased HR (HR = 103) and decreased SVR (SVR = 12), but ventricular collapse was not achieved. Inferior vena cava occlusion reduced preload, and ventricular collapse was achieved at speeds as low as 11,000 rpm. Esmolol (beta1 antagonist) decreased HR (HR = 55) and contractility, and ventricular collapse was achieved at 11,500 rpm. Episodes of ventricular collapse were characterized initially by the pump output exceeding the venous return and the aortic valve remaining closed throughout the cardiac cycle. If continued, the mitral valve would remain open throughout the cardiac cycle. Using these unique states of the mitral and aortic valves, the onset of ventricular collapse could reliably be identified. It is hoped that the ability to detect the onset of ventricular collapse, rather than the event itself, will assist in the development and the evaluation of control algorithms for rotary ventricular assist devices.
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PMID:Induction of ventricular collapse by an axial flow blood pump. 980 22

Percutaneous cardiopulmonary bypass support was electively instituted prior to coronary angioplasty in 16 patients at high risk for hemodynamic collapse. In all cases the dilated artery supplied greater than 2/3 of the functioning myocardium. Eight patients had moderate LV dysfunction with ejection fraction 25-40%. Eight patients had an ejection fraction less than 20%. A 21 French cannula and a 17 French cannula were percutaneously inserted into the femoral vein and artery. Cardiopulmonary bypass support was instituted using a Bio-Medicus centrifugal pump just prior to coronary angioplasty at flow rates of 3.5-5 liters/minute. Thirteen patients had single vessel angioplasty and three patients had multivessel angioplasty. Complete loss of systolic function was observed in 9 (56%) patients. This finding when present confirms the absolute requirement for cardiopulmonary support. Technical success was achieved in all 16 patients (100%), clinical success was achieved in 14 patients (88%). Patient followup (mean 10 months) revealed 3 patients with class I-II angina and 10 patients were asymptomatic. There was one late death. In conclusion, percutaneous cardiopulmonary bypass support for carefully selected high risk patients may allow coronary angioplasty to be performed safely and effectively despite complete loss of systolic function during balloon inflation.
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PMID:Clinical application of percutaneous cardiopulmonary bypass for high risk coronary angioplasty. 1014 76

A 21-year-old woman was referred to our hospital for sudden onset of right flank distension. Ultrasonography, abdominal CT scan and MRI revealed a giant cyst 20 x 11 x 10 cm on the right kidney. Percutaneous puncture of the lesion was performed and fluid was drained. The fluid was yellowish and puriform. Gradually, the drainage fluid creatinine concentration increased. Cystography revealed communication between the lesion and the pyelocalyceal system. The patient underwent drainage for 25 days, causing the cyst to almost fully collapse. No recurrence has been detected in the follow-up for about 1 year. This case is the 38th case of the rupture of a renal cyst reported in the Japanese literature. We reviewed 37 cases of rupture of renal cysts previously reported in Japan.
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PMID:[Spontaneous rupture of infected renal cyst presenting sudden onset of right flank distension: a case report]. 1523 85

A 21-year-old patient with repaired double-outlet right ventricle and normal ventricular function underwent internal cardioverter defibrillator implantation for primary prevention of sudden death. First occurrence of spontaneous ventricular tachycardia resulted in hemodynamic collapse and syncope but the internal cardioverter defibrillator rescued the patient. ICD implantation for primary prevention may be an appropriate goal in adults with repaired congenital heart disease, even in the setting or normal ventricular function.
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PMID:Defibrillator for primary prevention in congenital heart disease. 1530 72


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