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Biomedical subjects

J M Porter

Publications and source records attributed to J M Porter.

At least 307 records · Page 17Linked to original sources
PubMed1975

Effect of low dose intra-arterial reserpine on vascular wall norepinephrine content.

A number of reports in recent years have indicated that the administration of low dose intra-arterial reserpine has resulted in significant clinical improvement in patients with symptomatic vasospasm, with the benefits presumably resulting from regional vascular wall norepinephrine depletion with resultant vasodilatation. However, to date, there has been no evidence that such low dose reserpine actually alters vascular wall norepinephrine content. This study was performed to determine both regional and systemic effects of low dose intra-arterial reserpine on vascular-wall norepinephrine content, and the duration of any alterations. Twenty-four mongrel dogs had vascular segments excised and assayed for norepinephrine content, before and for up to 4 weeks following a single injection of reserpine, 0.01 mgm/kg, into one femoral artery. The results indicate a pronounced norepinephrine depletion in the injected femoral arterial system, with the reduction persisting for 2-4 weeks, at which time complete norepinephrine recovery occurred. The visceral vessels sampled also showed considerable norepinephrine depletion, indicating systemic spill-over of the drug from the injected peripheral arterial tree. The visceral vessels, however, showed maximal depletion at 24 hours, with recovery by 7 days.

Animals↗
PubMed1975

The diagnosis and treatment of Raynaud's phenomenon.

Twenty-five patients with Raynaud's phenomenon, including 20 with associated diseases and five with primary Raynaud's disease, were evaluated with sequential determinations of digital temperature recovery time after cold exposure and magnification hand arteriography before and after cold exposure and before and after intra-arterial reserpine. A variety of immunologic screening tests were performed, and the clinical response to oral guanethidine of phenoxybenzamine was determined. Temperature recovery time was prolonged in all but two patients with Raynaud's phenomenon before treatment. Arteriography revealed luminal obstruction of variable degree in all but two patients with Raynaud's phenomenon but not in those with Raynaud's disease. Radiographic vasospasm was noted in all patients. Patients with Raynaud's symptoms had a markedly greater vasospastic response to cold exposure than did three control patients without Raynaud's symptoms. Arteriography 48 hours after intra-arterial reserpine repeat revealed decreased vasospasm and a decreased vasospastic response to cold in most patients. A variety of serum protein and serologic aberrations were detected, with only eight patients being free of immunologic abnormalities, Nineteen patients were treated with guanethidine alone, three with guanethidine-phenoxybenzamine combination, and one with phenoxybenzamine alone. Good or excellent clinical results were noted in 19 of the 23 patients treated, with an average follow-up to date of 12 months.

Adult↗
PubMed1975

Comparison of heparin and streptokinase in the treatment of venous thrombosis.

Heparin or streptokinase was administered in a prospective randomized fashion to 50 patients with phlebographically confirmed venous thrombosis of the extremities of 14 days or less duration. A total of 49 patients completed the investigative protocol with 26 receiving heparin and 23 receiving streptokinase. All patients were evaluated with sequential phlebograms. Complete thrombolysis with restoration of venous valve function occurred in one of 26 patients receiving heparin and in six of 23 patients receiving streptokinase. Fifty per cent of the patients treated with streptokinase with a total duration of symptoms of three days or less achieved complete lysis. The total incidence of therapeutic complications was similar in the two groups, but was more severe in the streptokinase treated patients.

Administration, Oral↗
PubMed1975

Treatment of experimental frostbite with intra-arterial sympathetic blocking drugs.

A number of experimental and clinical studies have shown that early regional surgical sympathectomy decreases tissue loss following frostbite, presumably by relieving vasospasm and increasing blood flow. This study was performed to determine if a decrease in tissue loss following a standard cold injury could be obtained following a regional "medical sympathectomy" achieved by the intra-arterial administration of sympathetic blocking drugs. A standard cold injury was produced in rabbits and the animals were divided into nine treatment groups. Various treatment modalities were evaluated, including rapid rewarming, intra-arterial reserpine and tolazoline, and intravenous low molecular weight dextran. In the slowly rewarmed animals, the usual clinic situation, the regional intra-arterial administration of reserpine and tolazoline significantly reduced tissue loss, equalling the results obtained in the rapidly rewarmed group. These results indicate that the early achievement of a regional "medical sympathectomy" may be of benefit in reducing tissue loss following frostbite in patients, especially in those in whom rapid rewarming cannot be performed.

Animals↗
PubMed1974

Ergot intoxication: historical review and description of unusual clinical manifestations.

Clinical ergotism as seen today results almost exclusively from the excessive intake of ergotamine tartrate in the treatment of migraine headache. Although both gangrenous and convulsive symptoms are seen in naturally occurring ergotism resulting from the ingestion of fungus infected rye, only gangrenous ergotism has been reported following the excessive ingestion of ergotamine tartrate. The symptoms of both iatrogenic and naturally occurring ergotism appear to result from regional ischemia caused by ergot induced vasospasm. This report discribes experiences in the diagnosis and management of two patients with unusual manifestations of iatrogenic ergotism. One patient presented with ischemia of all extremities and bilateral foot drop probably due to ischemic damage to the common peroneal nerves, a finding not previously described in ergot intoxication. The foot drop totally resolved in several months following the discontinuation of ergot. A second patient presented with unilateral leg ischemia and transient monocular blindness, both of which resolved after discontinuation of ergot. Both patients displayed typical angiographic findings of ergotism. There is no convincing evidence that any treatment other than discontinuation of ergotamine is of benefit in the treatment of iatrogenic ergotism.

Adult↗
PubMed1974

Axillary-axillary artery bypass for the correction of subclavian artery occlusive disease.

Numerous procedures have been proposed for the correction of symptomatic subclavian artery occlusive disease, none of which have been uniformly accepted by vascular surgeons. During the past 21 months we have successfully treated six patients with symptomatic subclavian artery occlusive disease by the construction of an axillary-axillary artery bypass. There were three complications in this small series, a wound hematoma, a case of median nerve parasthesias, and a late graft thrombosis, possibly caused by external pressure on the graft. These complications have not caused any serious morbidity. All patients have been followed to the present time, all have experienced symptomatic improvement and none has developed any symptoms of donor arm ischemia. Axillary-axillary artery bypass is currently our procedure of choice for the correction of symptomatic subclavian artery occlusive disease because of its effectiveness, absence of serious morbidity and ease of performance.

Axillary Artery↗