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Biomedical subjects

J M Porter

Publications and source records attributed to J M Porter.

At least 253 records · Page 14Linked to original sources
PubMed1984

Pentoxifylline in the treatment of intermittent claudication of the lower limbs.

Pentoxifylline, a methyl xanthine analogue was evaluated for treatment of intermittent claudication in a double-blind placebo controlled parallel group study in seven centers in the United States. Tests were performed on 128 cases, including 42 who took pentoxifylline (600 mg by mouth daily, increased stepwise to 1200 mg daily at the end of one month) and 40 who took placebo for 24 weeks. Twenty-five patients on pentoxifylline and 21 on placebo were dropped from the study for reasons unrelated to the drug. Walking ability on a treadmill was increased significantly after 2 weeks and remained so throughout the study in the pentoxifylline vs. the placebo group. Ability to walk until first experiencing intermittent claudication was a more sensitive index than the maximum ability to walk. The drug did not cause changes in blood pressure or in heart rate. Other than mild nausea, there were no significant side effects.

Clinical Trials as Topic↗
PubMed1984

Cardiac output after burn injury.

Cardiac output after burn injury has been measured by the non-invasive method of impedance plethysmography. An initial study of 143 normal subjects was undertaken in order to investigate variations in cardiac output with age. Fifteen patients were monitored during resuscitation after extensive burns. Fourteen patients showed a depression of stroke volume below the lower limits of the normal range, derived from the initial study on normal people.

Adolescent↗
PubMed1983

Blood flow in the common femoral artery. Evaluation in a vascular laboratory.

Accurate knowledge of the hemodynamics of the common femoral artery is a critical part of both the preoperative evaluation of patients with peripheral vascular disease and the postoperative follow-up examination. Interrogation of the iliofemoral system with determinations of palpable pulse status, Doppler analog waveforms, and upper thigh pressure ratios has yielded an overall sensitivity of 91 percent and a specificity of 85 percent in the detection of inflow stenosis. This degree of accuracy (89 percent) allows practical surgical decisions to be based on the results of these noninvasive studies.

Aged↗
PubMed1983

Alpha-adrenergic receptors in platelets from patients with Raynaud's syndrome.

The pathophysiologic basis for spastic Raynaud's syndrome remains undefined but may be related to altered adrenergic activity. The relationship between Raynaud's syndrome and alterations in adrenergic receptor populations was examined in the present study by evaluation of alpha 2-adrenergic receptors in platelets. Direct binding assays revealed 78 +/- 8 fm/mg protein of alpha 2-adrenergic receptors in the platelets from control subjects. Similar levels of alpha 2-adrenergic receptors were observed in patients with obstructive Raynaud's syndrome. In contrast, platelet alpha 2-adrenergic receptor levels were significantly elevated (182 +/- 15 fm/mg protein) in the platelets from patients with spastic Raynaud's syndrome. These results indicate the presence of an altered alpha 2-adrenergic receptor population in the platelets from patients with spastic Raynaud's syndrome, which may be related to the vasospasm experienced by these patients.

Adult↗
PubMed1983

Lipids of human atherosclerotic plaques and xanthomas: clues to the mechanism of plaque progression.

While the content of fatty streaks and fibrous plaques has been extensively studied in autopsied specimens, little is known about the lipid composition of advanced human atherosclerotic plaques requiring surgical removal. We have analyzed free cholesterol, cholesteryl ester, and the cholesteryl ester fatty acid content in 19 carotid and 7 femoral obliterative plaques obtained at endarterectomy. These were compared with values from each subject's plasma and from xanthomas removed from eight patients. The total cholesterol content was 75.1 mg/g dry weight for carotid plaques, 56.0 mg/g for femoral plaques, and 106.8 mg/g for xanthomas. The free cholesterol content was 56.6% and 50.4% of the total cholesterol for carotid and femoral plaques, respectively, while the free cholesterol of xanthomas was only 25.5%. The fatty acids of cholesteryl esters were analyzed in an attempt to identify the site of their esterification, i.e., within plasma or within plaque. This can be determined using the ratio of linoleic acid (18:2) to oleic acid (18:1) in the cholesteryl ester. The ratios were 0.36 for xanthoma, 1.62 for carotid plaque, 1.73 for femoral plaque, and 2.51 in plasma. These data emphasize two chemical changes occurring with evolution of the atherosclerotic process: 1) The cholesteryl ester fatty acid composition of the plaque becomes increasingly similar to that of plasma, and 2) there is a continuing increase in the percentage of free cholesterol. These alterations reflect a decreased metabolic efficiency within atherosclerotic lesions and may initiate events that enhance plaque progression.

Arteriosclerosis↗
PubMed1982

Pentoxifylline efficacy in the treatment of intermittent claudication: multicenter controlled double-blind trial with objective assessment of chronic occlusive arterial disease patients.

The efficacy, safety, and tolerance of pentoxifylline (Trental, Hoechst-Roussel Pharmaceuticals, Inc.) in the treatment of intermittent claudication associated with chronic occlusive arterial disease (COAD) were evaluated in a double-blind, placebo-controlled, parallel-group, multicenter clinical trial involving a total of 128 outpatients. The response to treatment was ascertained at regular intervals during the trial by measuring the distance walked prior to the onset of claudication when patients were subjected to a standardized treadmill test. Pentoxifylline given orally in doses up to 1200 mg/day was significantly more effective than placebo in increasing both the initial and absolute claudication distances in patients with COAD. Reduction of lower limb paresthesias also suggested greater clinical improvement in the pentoxifylline treated patients. These results support the hypothesis that pentoxifylline reduces blood viscosity by improving red cell flexibility, and thereby enhances blood flow in patients with COAD. White the precise mode of therapeutic action requires clarification, pentoxifylline was well tolerated with minimal unwanted effects.

Aged↗
PubMed1982

Arm ischemia secondary to giant cell arteritis.

Six cases of arterial insufficiency of the arm secondary to giant cell arteritis are described, all in elderly white women. The clinical presentation of the occlusive disease ranged from an asymptomatic incidental physical finding to an alarming picture of severe ischemia. All patients were treated with steroids and had subsequent stabilization or improvement of extremity symptoms. Vascular reconstruction was also performed in two patients, one of whom developed rest pain after graft occlusion. Another patient had a cerebral infarction while taking prednisone, despite control of large vessel vasculitis. This study indicates that giant cell arteritis should be considered in cases of occlusive disease of the arms, especially in elderly women. Giant cell arteritis is a seriously morbid and potentially fatal disease which justifies a thorough evaluation when sufficient evidence is present to suggest the diagnosis. The response to steroids is usually adequate to eliminate the need for early surgical intervention.

Aged↗
PubMed1982

Treatment of finger ischemia with Bier block reserpine.

Fourteen patients with severe Raynaud symptoms, including four patients with ulceration of the fingers, were treated by regional medical sympathectomy achieved by the tourniquet controlled intravenous injection of reserpine. Nine of the patients had significant objective clinical improvement which, in each patient, correlated with the demonstration of vasospasm on pretreatment studies. The five patients without improvement had advanced organic obstructive arterial disease without vasospasm.

Adult↗
PubMed1982

Pharmacologic treatment of intermittent claudication.

Twenty-six patients with severe short-distance claudication underwent a 24-week, randomized, double-blind, parallel-group evaluation of the efficacy of pentoxifylline in the treatment of intermittent claudication. The primary variables analyzed were the initial and absolute claudication distances as determined by standardized treadmill walking. A statistically significant improvement in both parameters was present in the pentoxifylline-treated patients. Nausea was the only drug side effect noted.

Double-Blind Method↗
PubMed1981

Lower-extremity amputations for ischemia.

During the past eight years, we performed 312 lower-extremity amputations for ischemia. Amputation requiring no prosthesis was achieved in 31% of patients, knee joint preservation in 72%, and overall primary amputation healing in 75%. Amputation mortality was 6%. The use of prior arterial reconstruction, careful wound care, and willingness to accept nonhealing of trial amputations were important factors in obtaining the most distal possible healed amputation. An accurate evaluation of the impact of new methods of selecting amputation level and evaluating amputation results can only be achieved by a report of the total institutional amputation experience, not by reports of a single type of amputation.

Aged↗
PubMed1981

Precise diagnosis of aortic anastomotic aneurysm by computed tomographic scan.

False aneurysms that involve aortoprosthetic anastomoses may be difficult to diagnose prior to fatal rupture. We report a case in which a false aneurysm that developed six year after aortofemoral-graft insertion was accurately diagnosed by a computed tomographic (CT) scan after both ultrasonography and angiography had failed to make the diagnosis. The ability of CT scanning to demonstrate anastomotic aneurysms and accurately determine the presence of periaortic hemorrhage is discussed.

Aged↗
PubMed1981

Extended profundaplasty. Indications and techniques with results of 46 procedures.

We performed extended profundaplasty 46 times in 36 patients. Twelve procedures were performed for ischemic ulcers, 23 for ischemic rest pain and 10 for short-distance claudication. Fourteen procedures were performed independently, 21 to provide outflow for proximal bypass grafts, and 11 were combined with distal bypass grafts. Four of the 46 procedures failed; the rest have been successful for limb salvage or relief of symptoms at a mean follow-up of 15 months. Technical points emphasized are autogenous patch closure of the entire endarterectomy site and careful attention to end-point detail. The results demonstrate that this procedure provides durable limb revascularization.

Aged↗
PubMed1981

Evaluation and management of patients with Raynaud's syndrome.

The wide spectrum of associated disorders, the previous lack of understanding of pathogenesis, and the older, arbitrary terminology in relation to ultimate prognosis have led to confusion in the evaluation and management of Raynaud's syndrome. A unified concept of pathogenesis, in which vasospasm and arterial occlusive disease are the fundamental lesions, is presented herein. The associated disorders found in our 219 patients with continuous follow-up are listed and related to the underlying pathogenetic mechanisms. Our approach to diagnosis led to the discovery of an associated condition in 71 percent of our patients. The evaluation can be done in a cost-effective manner. The emphasis of treatment should be on conservative medical management, with avoidance of cold and tobacco and judicious use of pharmacologic agents remaining the cornerstones of therapy. Cervicothoracic sympathectomy has no role in the treatment of Raynaud's syndrome.

Adult↗
PubMed1981

Bed-time food supplements and sleep: effects of different carbohydrate levels.

Blood glucose levels were altered during sleep by means of manipulating carbohydrate (CHO) intake through bed-time food supplements. Protein and fat intake were minimally affected. Subjects underwent all conditions in a balanced designed. A high CHO condition resulted in significantly reduced stages 1 + 0 sleep over the whole night and significantly increased REM sleep during the first half of the night; there seemed to be a reciprocity between these two changes. High CHO also produced a whole-night significant decrease in stages 4 sleep, which persisted into the recovery night. Few significant differences between the other conditions of low and zero CHO were found. Sleep onset was not affected. It was concluded that relatively high blood glucose levels were required to alter sleep, and perhaps lead to more 'restful' sleep. The present findings were similar to those of related studies. The REM sleep changes were discussed in relation to increases in brain serotonin synthesis mediated by elevated blood glucose levels.

Adult↗
PubMed1981

Raynaud syndrome.

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Adrenergic beta-Antagonists↗
PubMed1981

Percutaneous angiographic embolization: a procedure of increasing usefulness: review of a decade of experience.

During the past decade percutaneous therapeutic vascular occlusion was performed on 152 occasions in 124 patients. The primary indication for vasoocclusive therapy was acute or recurrent bleeding. Upper gastrointestinal bleeding from arterial sources was controlled in 92 percent of patients and acute variceal bleeding in 83 percent. Renal embolization was performed for palliation of severe pain and hematuria from unresectable renal primary or secondary malignancies, to decrease blood loss and facilitate surgery in operable renal tumors, and for ablation of renal function to control chronic protein loss or severe hypertension. Our encouraging experience convinces us that transcatheter embolization is a useful, safe and effective procedure in selected patients. It seems certain that the technique of therapeutic embolization will be improved, its indications extended and its application become commonplace whenever angiographic skills and facilities exist.

Angiography↗