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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vascular resistance was determined during hypothermic perfusion of rabbit kidneys after various periods of warm ischemia. Ischemia was induced by clamping of the renal artery, or of the renal artery and vein, in situ. Studies were made after periods of clamping ranging from 0 to 180 min. The perfusing fluid was 5% Dextran of low molecular weight in balanced saline solution (Tis-U-Sol), with addition of 5 mg % Papaverin. When the renal artery was clamped for more than 15 min, vascular resistance increased. Maximal resistance was reached after 60 min of clamping, and was 3 times as high as that value in the control group of kidneys which were not clamped. The vascular resistance attained after 60 min of clamping did not further increase when clamping was maintained for 180 min. When both the renal artery and the renal vein were clamped vascular resistance first increased after 30 min. Maximal resistance was reached after 60 min of clamping, but was only 1/2 of that level seen when the renal artery alone was clamped.
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PMID:Vascular resistance in hypothermically perfused kidneys damaged by warm ischemia. 127 30

The purpose of this study was to determine if intraarterial vasodilating drugs could augment the vasodilation produced by sympathetic blockade, such as occurs during epidural anesthesia. Papaverine (2 mg/min), nitroglycerin (1 microgram/kg/min), aand saline were infused into the femoral artery before and after lumbar sympathectomy in six arterially isolated canine hindlimbs. Femoral blood flow was controlled with a perfusion circuit at baseline (80 ml/min), half-baseline (40 ml/min), and low (5 ml/min) flow rates so that hindlimb mean arterial pressure served as an index of peripheral vasodilation. At low flow, hindlimb arteriovenous oxygen content difference increased from 1.4 (baseline) to 6.2 ml O2/dl, consistent with peripheral ischemia. At baseline flow before sympathectomy, papaverine and nitroglycerin caused a decrease in hindlimb mean arterial pressure of 30% and 18%, respectively (p less than 0.01 vs saline control), equivalent to the decreases of 31% and 16% after sympathectomy (p less than 0.01). At half-baseline, papaverine and nitroglycerin reduced hindlimb mean arterial pressure by 22% and 12%, respectively (p less than 0.01), and caused comparable vasodilation after sympathectomy. Neither drug significantly changed hindlimb mean arterial pressure at low flow. Sympathectomy itself reduced hindlimb mean arterial pressure by 23% at baseline flow (p less than 0.01), by 18% at half-baseline flow (p less than 0.01), but had no effect at low flow. We conclude that intraarterial papaverine and nitroglycerin cause peripheral vasodilation that is synergistic with sympathectomy-induced adrenergic blockade, but they cannot augment vasodilation caused by peripheral ischemia.
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PMID:The interaction of vasodilating drugs and sympathetic blockade in normal and ischemic canine hindlimbs. 190 19

Acute nonocclusive mesenteric ischemia was produced in dogs anesthetized with pentobarbital by reversible pericardial tamponade, which reduced cardiac output and mesenteric blood flow by approximately 42% and 53%, respectively. Papaverine, infused into the cephalic (superior) mesenteric artery at an average dose of 100 micrograms/kg X min, was completely effective in restoring mesenteric blood flow and correcting altered intestinal oxygen kinetics. However, the same dose of papaverine given intravenously to other dogs was ineffective in correcting the deranged hemodynamics and oxygen kinetics. Larger doses of intravenous papaverine returned mesenteric blood flow toward control values but caused systemic arterial hypotension. In comparison, synthetic urotensin I, a highly selective mesenteric vasodilator peptide, produced results identical to those produced by intraarterial papaverine, even though it was given intravenously in small doses (average dose: 13 ng/kg . min). Moreover, it produced no systemic effects. These results suggest that intravenous urotensin I is as effective as intraarterial papaverine in a model of severe mesenteric ischemia, and that it should be examined for a possible clinical role in the treatment of acute mesenteric ischemia in humans.
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PMID:Comparison of an intravenous selective mesenteric vasodilator with intraarterial papaverine in experimental nonocclusive mesenteric ischemia. 371 84

The anti-hypoxic effect of cinnarizine was studied using the following experimental methods: hypobaric and anoxic hypoxia in mice, complete ischemia by decapitation in mice and hemic hypoxia in rats. Papaverine, xanthinol nicotinate and naftidrofuryl were used as reference drugs. In hypobaric and anoxic hypoxia the interaction of cinnarizine with the effect of prostacyclin (PGI2) was investigated. Cinnarizine showed an anti-hypoxic effect in all the methods used. It was more effective in hypobaric and anoxic hypoxia, in incomplete ischemia by decapitation, and less effective in hemic hypoxia. Cinnarizine potentiated the effect of PGI2 shifting the anti-hypoxic dose-response curve of PGI2 to the left. Suggestions as to the possible mechanism of anti-hypoxic action of cinnarizine are made.
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PMID:Study on the anti-hypoxic effect of cinnarizine and its interaction with prostacyclin. 637 43

The vasodilators papaverine hydrochloride, tolazoline hydrochloride, and isoproterenol hydrochloride were infused into the superior mesenteric artery (SMA) of dogs in which an ischemic Thiry-Vella colon loop had been formed. The washout of an intra-arterial injection of xenon Xe 133 to the normal and ischemic colon segments was used to measure bowel wall blood flow. Tolazoline and papaverine significantly increased the washout of 133Xe, but isoproterenol did not. Papaverine increased SMA flow. Neither of these two drugs altered the systemic blood pressure or pulse. However, isoproterenol augmented the SMA flow and pulse by factors of 1.8 and 1.5, respectively. These results support the favorable clinical reports that have found papaverine and tolazoline of use in the treatment of nonocclusive bowel ischemia.
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PMID:Effect of intra-arterial vasodilators on blood flow in ischemic dog colon. 737 62

Acute mesenteric ischemia represents one to two percent of all gastrointestinal illnesses. There are three possible causes of acute arterial mesenteric ischemia: embolism, thrombosis, and nonocclusive mesenteric insufficiency. The key to early diagnosis is a high index of suspicion. The classic clinical picture of obvious cardiac disease, sudden onset of severe abdominal pain and gastrointestinal emptying, is not always present. Serum markers and plain films are often nondiagnostic but may suggest acute arterial mesenteric ischemia. Angiography establishes the diagnosis and allows for planning of aortomesenteric bypass, if indicated. Papaverine is immediately instilled to decrease splanchnic vasoconstriction. Embolic and thrombotic disease is treated by laparotomy with re-establishment of visceral perfusion. Only after blood flow is restored is nonviable bowel resected. Clinical methods of assessing intestinal viability include Doppler scanning, intravascular dyes, and tissue oximetry. The decision to perform a second-look laparotomy is made prior to closure of the abdomen. Pharmacologic treatment is the mainstay of nonocclusive ischemia. Surgery is reserved for clinical deterioration. Survival is dependent on the cause and extent of occlusion as well as the rapidity of diagnosis and therapy. Bowel necrosis results in mortality rates between 80 percent and 95 percent.
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PMID:Mesenteric ischemia. Acute arterial syndromes. 760 44

Flap ischemia is often encountered during pedicled and free tissue transfer. In this study, the vascular effects of varying doses of lidocaine, papaverine, and a combination of the two agents were evaluated and compared in an in vitro and in vivo model in the rabbit carotid artery. In the in vitro study, 14 rings from the rabbit carotid artery were bathed in Krebs-Ringers solution and stretched progressively to an optimal tension of 3.7-4.2 grams. Their isometric contractile activity was measured. The specimens were precontracted with norepinephrine (1 microM), and a dose response curve was established by adding cumulatively either lidocaine (to 7 arterial rings) or papaverine (to 7 arterial rings) at increasing concentrations. In the in vivo study, microvascular anastomoses were performed bilaterally in the rabbit carotid artery in 30 animals using 9-0 nylon suture and standard microsurgical techniques. In each animal, one side was treated with heparinized sodium chloride and served as the control. The other side was treated blindly, during and after the anastomoses, with a topical application of 1 ml of either lidocaine 2% (n = 5), lidocaine 20% (n = 5), papaverine (30 mg/ml, n = 5), lidocaine 2% combined with papaverine (30 mg/ml, n = 5), or lidocaine 20% combined with papaverine (30 mg/ml, n = 5). For 30-60 minutes after the procedure, blood flow changes in the vessels were continuously monitored with a transonic doppler applied to both carotid arteries. The 20% lidocaine group was flushed with saline at the end of the first hour and monitored for an additional 60 minutes. Papaverine elicited a concentration-dependent relaxation of norepinephrine precontracted carotid artery rings in vitro. Lidocaine elicited a biphasic response, with low concentrations (10(-6)-10(-4) M) increasing the norepinephrine-induced contraction and high concentrations (10(-4)-10(-2) M) relieving this contraction. Microsurgical anastomosis produced a significant decrease of blood flow through the rabbit carotid artery as measured by the transonic doppler. Drug application did not alter the systemic blood pressure of the animals. Topical application of lidocaine 2% did not significantly change the blood flow after microvascular anastomosis. Topical application of lidocaine 20%, papaverine (30 mg/ml), or lidocaine (2% or 20%) combined with papaverine significantly increased the blood flow in the rabbit carotid artery. In the lidocaine 20% group, the blood flow remained significantly increased after the drug was flushed with heparinized saline solution. These results demonstrate that topical lidocaine 20%, papaverine, and lidocaine 2% or 20% combined with papaverine significantly increase blood flow in the rabbit carotid artery after microvascular anastomosis. The data confirm the use of papaverine and lidocaine 20%, alone or in combination, as spasmolytics during clinical microsurgery. This suggests that lidocaine 2% alone is not the ideal drug to relieve vascular constriction, and further studies on the clinical use of low concentrations of topical lidocaine in microsurgery is warranted.
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PMID:Drug-induced vasodilation: in vitro and in vivo study on the effects of lidocaine and papaverine on rabbit carotid artery. 967 23

Mild hypothermia (32-34 degrees C of brain temperature) was used for brain protection in patients with progressive ischemic neurological deficits associated with severe cerebral vasospasm and who did not respond to medical treatment or intravascular angioplasty. Results showed that 2 of 3 patients in Hunt & Kosnik grade I to III and 2 patients who underwent delayed operation on day 5 and 9 each and had ischemic neurological deficits made good recovery with this treatment. Favourable outcome was obtained in 4 of 9 patients in grade IV and V. Mild hypothermia is thought to provide brain protection in critical ischemia due to severe cerebral vasospasm and can lengthen therapeutic time to employ angioplasty and intraarterial Papaverin infusion.
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PMID:Protective effect of mild hypothermia on symptomatic vasospasm: a preliminary report. 1145 87

An endovascular treatment of vasospasm following a subarachnoid aneurysmal haemorrhage is to be implemented if the patient presents clinical or biological symptoms arguing for brain ischemia in conjunction with increased Doppler velocities despite well controlled systemic haemodynamic. Treatment might be either pharmacological or haemodynamic. Calcium and phosphodiesterase inhibitors can be administered. The former could also provide a neuroprotective effect as compared to the latter. In Europe, nimodipine is widely used whereas nicardipine and verapamil are the major molecules administered in North America where iv nimodipine is not FDA approved. Papaverine is less used nowadays because of its short duration of action and of the risk of aggravation of raised intracranial pressure. Balloon angioplasty has a long lasting effect but can be applied only to proximal spasm. Complications of its use are rare but life threatening. In some cases, both the pharmacological approach and the mechanical approach are used in combination.
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PMID:[Endovascular treatment of vasospasm following subarachnoid aneurysmal haemorrhage]. 1793 40

Spinal cord injured (SCI) patients have sexual disorders including erectile dysfunction (ED), impotence, priapism, ejaculatory dysfunction and infertility. Treatments for erectile dysfunction include four steps. Step 1 involves smoking cessation, weight loss, and increasing physical activity. Step 2 is phosphodiesterase type 5 inhibitors (PDE5I) such as Sildenafil (Viagra), intracavernous injections of Papaverine or prostaglandins, and vacuum constriction devices. Step 3 is a penile prosthesis, and Step 4 is sacral neuromodulation (SNM). Priapism can be resolved spontaneously if there is no ischemia found on blood gas measurement or by Phenylephrine. For anejaculatory dysfunction, massage, vibrator, electrical stimulation and direct surgical biopsy can be used to obtain sperm which can then be used for intra-uterine or in-vitro fertilization. Infertility treatment in male SCI patients involves a combination of the above treatments for erectile and anejaculatory dysfunctions. The basic approach to and management of sexual dysfunction in female SCI patients are similar as for men but do not require treatment for erectile or ejaculatory problems.
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PMID:Management of sexual disorders in spinal cord injured patients. 2283 80


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