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Biomedical subjects

R R Tyson

Publications and source records attributed to R R Tyson.

At least 19 recordsLinked to original sources
PubMed1987

Intra-arterial thrombolytic therapy in peripheral vascular disease.

This is a prospective analysis of patients undergoing 34 treatments for arterial thromboses and emboli with intra-arterial thrombolytic therapy. These included acute arterial thromboses, graft thromboses, arterial emboli and pulmonary emboli. Twenty-seven of 34 patients treated had evidence of lysis, 14 had complete lysis, 13 had partial lysis and seven had no lysis. Both patients with occlusions for longer than three weeks failed to respond to treatment. Thirty-two patients presented with ischemia of the extremity. Twenty-four of 32 patients had limb salvage with eight subsequently undergoing amputation. No patient who was treated for claudication or who had a patent popliteal artery distal to the acute thrombosis failed to respond. Extensive tibioperoneal occlusion generally responded poorly compared with femoropopliteal or more proximal thrombi. Complications are divided into direct (drug related) and indirect (technique related). Four of 34 patients had an extensive hemorrhagic event with two suffering intracranial bleeding who ultimately died. All of the patients with extensive hemorrhagic episodes had serum fibrinogen levels of less than 50 milligrams per cent. During infusion, extensive distal emboli occurred in three with two of these patients requiring thrombectomy; one instance resolved with infusion. Minor distal emboli occurred in three and all resolved with continued infusion. We believe that intra-arterial thrombolytic therapy is a valuable adjunct in the treatment of acute arterial occlusion. The local infusion of lytic agents appears to be more efficient than systemic therapy. The tip of the infusion catheter should be placed into the thrombus for optimal lysis, but not advanced too far. The fibrinogen level is a sensitive indicator of systemic lysis and should be maintained above 50 milligrams per cent. Systemic lysis is obtained even with low dose infusion when therapy exceeds six hours. Intra-arterial infusion of thrombolytic agents can be performed safely in the immediate postoperative period as well as intraoperatively if specific guidelines are followed. Patients with massive unilateral pulmonary embolism can be efficiently treated with intra-arterial lytic therapy.

Fibrinogen↗
PubMed1984

Tissue CEA in colorectal carcinoma.

Immunoperoxidase method can be used to detect cellular or tissue CEA. Forty formalin-fixed paraffin-embedded specimens of colorectal carcinoma, 19 from patients who survived for five years after resection, and 21 from patients who died within five years were studied. Cellular CEA was present in 100 per cent of the specimens. Accurate quantitative evaluation of cellular CEA is currently not feasible. Therefore, the mere presence of cellular CEA has no prognostic value.

Carcinoembryonic Antigen↗
PubMed1984

Real-time B-mode carotid imaging. A three-year multicenter experience.

This report attempts to establish the place of real-time B-mode carotid imaging in the diagnosis of carotid artery disease through an analysis of the results of 3 years of experience in three major noninvasive vascular laboratories. Over 7000 patients were studied noninvasively with real-time B-mode carotid imaging and oculoplethysmography (OPG). Angiographic comparisons of 1723 vessels form the basis of this study. All tests were interpreted by physicians who had no knowledge of the angiograms. Images and x-ray films were classified by diameter of stenosis: grade I (0% to 39%), grade II (40% to 69%), grade III (70% to 99%), and grade IV (total occlusion). The effect of the imaging experience was determined by dividing the study into two periods. The results of image quality vs. accuracy and of combining the anatomic study (scan) and physiologic study (OPG) were also evaluated. The overall data show a specificity of 87% (985 of 1139), a sensitivity for grade II disease of 72% (193 of 267), a sensitivity for grade III of 66% (133 of 201), and a sensitivity for grade IV of 64% (74 of 116). With experience each center showed improvement of the imaging technique in diagnosing grade III (p greater than 0.1: not significant) and grade IV disease (p less than 0.0002: highly significant), although there was no improvement in the specificity and sensitivity of grade II disease. All scan errors were analyzed. Most errors were interpretation errors (27%: 90 of 338), scan/arteriogram mismatches (23%: 79 of 338), or poor-quality scans secondary to existing disease (22%: 75 of 338). There was a direct correlation of scan quality and accuracy, with a 97% specificity for grade I scans of good to excellent quality. When the scan and OPG agreed, there were uniform predictive values for all grades (88% to 93%). Sixteen of 79 scan/arteriogram mismatch vessels were operated on, and the scan proved more reliable in 86%. Real-time B-mode carotid imaging is a reliable technique for defining the normal carotid artery and is becoming increasingly sensitive in identifying existing disease. Despite its limitations, its strong points make it a valuable clinical tool.

Carotid Artery Diseases↗
PubMed1981

Prophylaxis of adhesions with low frequency sound.

Despite a multitude of ingenious ideas, a review of the literature has revealed no consistently acceptable results concerning adhesion prophylaxis. While pharmacologic avenues are far from exhausted, presently, there is no acceptable regimen. A double blind experimental study was performed with 130 Sprague-Dawley rats to determine the effect of high intensity low frequency sound on postoperative adhesion formation. Standard cecal crush was used to induce adhesions in rats which were then divided into four groups. The control rats exhibited 83 per cent adhesion formation while the rats in the other groups displayed an incidence inversely related to the duration of low frequency sound exposure. A reduction to 23 per cent adhesion formation was achieved in the group exposed to infrasound for 12 days. The controlled application of low frequency sound generates micromotion of the abdominal organs; moving surfaces do not lend themselves to spanning fiber formation. Studies disclaim significant side-effects of low frequency sound in man nor were any detected in the rats used in this study.

Animals↗
PubMed1979

The elderly patient with severe arterial insufficiency of the lower extremity: limb salvage by femoro-popliteal reconstruction.

To determine the feasibility of limb salvage in elderly patients in whom severe ischemia of the lower extremity is present, the results of femoro-popliteal reconstruction done primarily for limb salvage were reviewed. Of 310 femoro-popliteal bypasses, 72 were performed on patients 70 years of age or older. In the over-70 group, ischemic necrosis was present in 70.8% rest pain in 22.2%, and claudication in 7.0%. Initial limb salvage patients 70 years of age or older was 71.4%. Cumulative limb salvage at 5 years was 51.1% and at 10 years was 44.8%. Operative mortality, including mortality of subsequent amputation, when required, was 8.3%. Appreciable limb salvage can be achieved by femoro-popliteal arterial reconstruction in lieu of primary amputation in elderly patients in whom severe arterial insufficiency of the lower extremity is present.

Age Factors↗
PubMed1979

Long-term results of 474 arterial reconstructions for severely ischemic limbs: a fourteen year follow-up.

A retrospective study of 474 femoropopliteal and femorotibial bypasses performed for limb salvage with a follow-up of up to 14 years is presented. The overall operative mortality rate was 4.2%. Initial limb salvage rate for femoropopliteal was 82.8% and for femorotibial, 67.9%. Cumulative limb salvage rate, as calculated by the life-table method, at 1, 5, 10, and 14 years for femorpopliteal was 67.6%, 59.7%, 54.0%, and 31.5%; for femorotibial 53.9%, 46.9%, 42.2%, and 42.2%. Initial and long-term salvage of severely ischemic lower extremities can be achieved in a large number of patients by revascularization to the popliteal and more distal arterial tree. Therefore we conclude that arterial reconstruction for salvage of severely ischemic limbs should be considered in lieu of primary amputation in all patients with popliteal or tibial run-off.

Adolescent↗
PubMed1978

Reconstruction of an iliac vein: a case report and discussion.

A case report of a girl with anomalous venous drainage of a lower extremity who had a successful venous transplant is presented, along with a review of some factors thought to be important in venous grafting. In our patient there are several factors that may have contributed to long-term patency. As demonstrated by venogram, there was no alternative or competing pathway for blood to drain from the leg. This would imply a high venous pressure driving blood through the graft. Autogenous vein was used. Local heparin may have been a contributing factor as well. Although growth of anastomosed arteries has been demonstrated, this is the first time growth of a venous transplant has been demonstrated in a human. This growth was in length as well as in diameter. We believe this experience lends encouragement to the use of venous transplant surgery, which may become more common.

Child↗
PubMed1977

A ten year study of medullary carcinoma of the breast.

In this large series of patients treated for medullary carcinoma of the breast by radical mastectomy, the over-all five year survival rate was 63.7 per cent and the ten year survival rate, 49.5 per cent. Although survival was adversely affected by axillary lymph node involvement, there was an equal incidence of such involvement, there was an equal incidence of such involvement in tumors less than 4 centimeters compared with those greater than 4 centimeters in size; however, patients with tumors greater than 4 centimeters in size fared poorer categorically than did those with smaller lesions. Women in the premenopausal period had one-third of the cancers and had a significantly better survival rate than did those in the postmenopausal period, despite a similar incidence of axillary lymph node involvement. Medullary carcinoma is among the small group of malignant tumors of the breast that have distinctly better five and ten year survival rates than other more common varieties.

Adult↗
PubMed1977

The technique of modified radical mastectomy.

The functional and cosmetic results of this modified radical mastectomy are superior to those achieved by standard radical mastectomy. The incidence of lymphedema of the ipsilateral arm, which is one of the feared complications from a standard radical mastectomy, appears to be decidedly less.

Axilla↗
PubMed1976

Femorotibial bypass in the elderly for revascularization of the severely ischemic lower extremity.

In the elderly, revascularization of a severely ischemic lower extremity with occlusion of both femoral and popliteal arteries often can be achieved by surgical construction of a distal bypass to the tibial or peroneal arteries. An aggressive diagnostic and therapeutic approach is necessary, in an attempt to prevent recourse to primary amputation. Femoroperoneal or femorotibial bypass can be performed safely and is recommended in elderly patients with advanced ischemia of a lower extremity with absolute indications for surgical intervention, e.g., gangrene, gangrenous ulceration or rest pain. A significant number of limbs can be salvaged by this method. Although the mortality rate in the older age groups is predictably higher, the overall rate for this operation compares favorably with that for primary amputation.

Adult↗
PubMed1976

Systemic arteriovenous fistula simulating severe valvular aortic stenosis.

A patient with a renal arteriovenous fistula is described. She was though to have valvular aortic stenosis because of a history of rheumatic fever, symptoms of congestive heart failure and syncope, and the presence of a harsh systolic murmur with a thrill in the aortic area. Cardiac catheterization revealed a left-to-right shunt of 8.7 L/min. Ligation of the fistula resulted in complete relief of the symptoms and attenuation of the murmur.

Aged↗