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Biomedical subjects

L M Taylor

Publications and source records attributed to L M Taylor.

At least 127 records · Page 7Linked to original sources
PubMed1990

Late complications after femoral artery catheterization in children less than five years of age.

Fifty-eight children who underwent diagnostic femoral artery catheterization before 5 years of age, from 5 to 14 years before the study, were randomly selected from approximately 300 surviving patients undergoing diagnostic femoral artery catheterization at our institution during the interval. Each patient underwent vascular laboratory segmental pressure and waveform examination and arterial duplex scanning, as well as lower extremity bone length radiographs, which were considered positive if the catheterized leg was greater than or equal to 1.5 cm shorter than the opposite leg. Thirteen children who had only venous catheterization served as controls. No arterial abnormalities were present in the control patients (mean ankle/brachial index, 1.01). Arterial occlusion was present in both limbs of five patients who had bilateral diagnostic femoral artery catheterization and in 14 limbs of 51 patients who had unilateral diagnostic femoral artery catheterization. Thus arterial occlusion was present in 33% of patients (19 of 58) and in 37% of limbs (24 of 65). The mean ankle/brachial index in the catheterized limbs was 0.79. Leg growth retardation was present in four limbs (8%) of 51 children undergoing unilateral diagnostic femoral artery catheterization and in one (8%) control patient. The inverse relationship between ankle/brachial index and leg growth retardation was significant (R = 0.47, p less than 0.0005). Only one patient had symptoms of arterial occlusion (claudication), and one patient had symptoms of leg growth retardation (gait disturbance). We conclude that arterial occlusion is common after diagnostic femoral artery catheterization in children less than 5 years of age, but that excellent collateral supply prevents leg growth retardation and/or symptomatic arterial insufficiency in most children.(ABSTRACT TRUNCATED AT 250 WORDS)

Arterial Occlusive Diseases↗
PubMed1989

Analysis of risk factors for myocardial infarction following carotid endarterectomy.

A 4-year experience with 249 consecutive carotid endarter-ectomies performed on 224 patients is reviewed for incidence of perioperative (30-day) myocardial infarction and early survival (mean follow-up, 21 months). Except in cases of unstable angina, coronary arterial disease was evaluated only by routine history, physical examination, and electrocardiogram. By these criteria, 73% of patients had evidence of coronary arterial disease. Patients underwent carotid endarterectomy after appropriate medical management and stabilization of coronary disease symptoms (angina and/or congestive heart failure). One (0.4%) fatal and nine (3.6%) nonfatal perioperative myocardial infarctions Early survival of patients with active symptoms of coronary disease who did not undergo coronary bypass was similar to those patients with preceding or subsequent coronary bypass. The results of this review suggest routine clinical evaluation for coronary arterial disease is sufficient in the large majority of cases prior to carotid endarterectomy. Considering the reported high mortality of coronary bypass among vascular surgical patients, it appears that an aggressive program screening for cardiac surgical candidates either by coronary arteriography or radionuclide studies prior to carotid endarterectomy is not warranted.

Arteriosclerosis↗
PubMed1989

Expression of calcitonin receptors during osteoclast differentiation in mouse metatarsals.

Metatarsal bones of 15-day-old mouse embryos contain proliferative tartrate-resistant acid phosphatase (TRAP) negative (-) osteoclast progenitors that progressively differentiate into multinucleated TRAP positive (+) osteoclasts. Using histochemical and autoradiographic techniques, we have examined the expression of calcitonin receptors during osteoclast differentiation in mouse metatarsals. Fresh mouse metatarsals from embryos aged 14-17 days and metatarsals from 15-day-old embryos cultured for 1, 2, 3, and 6 days were stained for TRAP. Calcitonin binding to osteoclasts and their precursors was studied by incubating metatarsals with [125I]salmon calcitonin (sCT) and quantitating grain counts from autoradiographs of tissue sections. Calcitonin receptors first appear on nonproliferating osteoclast precursors, most often just after or simultaneously with the development of TRAP activity. The effect of sCT on the development of TRAP+ mononuclear preosteoclasts was examined by culturing 15-day-old metatarsals in the continuous presence of 5 mU sCT for periods of up to 3 days and quantitating the number of TRAP+ mononuclear preosteoclasts that develop. Calcitonin did not affect the differentiation of osteoclasts up to the stage of the TRAP+ mononuclear preosteoclast.

Acid Phosphatase↗
PubMed1989

Prostaglandin E2 initially inhibits and then stimulates bone resorption in isolated rabbit osteoclast cultures.

Osteoclasts were isolated from the long bones of neonatal rabbits and cultured on devitalized bovine bone slices for 8, 24, 48 and 72 h with and without prostaglandin E2 (PGE2) (10(-6) M). The number of osteoclasts present at the end of the culture periods was counted after staining the cells for tartrate resistant acid phosphatase (TRAP). After removal of the cells, the resorption lacunae excavated by the osteoclasts were observed by scanning electron microscopy (SEM) and their size and depth calculated by computer-assisted morphometric and stereomorphometric techniques. PGE2 had no effect on the number of TRAP positive multinucleated osteoclasts, but decreased the number of TRAP positive mononuclear cells. The total area of the excavated pits and the area excavated per osteoclast in PGE2-treated cultures were decreased by 62 and 58% respectively after 8 h in culture. After 24 h in culture, the total excavated area and the excavated area per osteoclast were still 44 and 38% lower in the PGE2-treated cultures than in the corresponding control cultures. However, after 48 h of culture, resorptive activity in PGE2-treated cultures was consistently greater than in control cultures. In the course of a 48 h culture period, the PGE2 concentration decreased from 1.0 x 10(-6) to 0.3 x 10(-6) M. Thus, despite the continuous presence of PGE2, the resorptive activity of osteoclasts not only recovered from the transient inhibitory effect of PGE2, but was actually greater than in the control cultures. This confirms that the effects of PGE2 in isolated osteoclast preparations are inhibitory in short term cultures, but shows that the effects of PGE2 in such preparations are stimulatory in longer term cultures. Proliferating stromal cells with osteoblast-like characteristics comprised approximately 45% of the 'osteoclast' cultures at the start of the cultures, but their number increased to 93% of the total cell population at 48 h and to 98% at 72 h. Our results suggest that the PGE2-induced stimulation of osteoclastic activity represents an indirect effect mediated by stromal cells derived from bone marrow. Our results also indicate that the increased resorptive activity in PGE2 treated cultures can be accounted for by an increase in the size of the resorption lacunae and is not caused by an increase in osteoclast number.

Acid Phosphatase↗
PubMed1989

Role of revascularization to treat chronic nonhealing fractures in ischemic limbs.

The contribution of chronic limb ischemia to long-term nonunion of a lower extremity fracture was suggested in a single published case report from our group 13 years ago. We have since encountered three additional patients with nonunited lower extremity fractures occurring in limbs with arterial ischemia. In each of these four patients limb revascularization was undertaken in an effort to stimulate healing of the fracture. These patients had chronic (mean 6 months) nonunion of tibial (three) or femur (one) fractures associated with severe lower extremity ischemia (ankle/brachial index m = 0.33; range 0.24 to 0.5). All patients had histories of chronic lower extremity ischemia before the fracture (ischemic rest pain, 2; claudication, 2). All patients underwent angiography followed by lower extremity revascularization. Restoration of normal arterial supply to the fracture site was followed by healing of the fracture in all patients. To our knowledge, this represents the first reported series of patients undergoing elective limb revascularization to stimulate healing of the fracture. Widespread appreciation of this relationship by orthopedic surgeons may be of considerable clinical importance.

Aged↗
PubMed1989

Epithelioid hemangioendothelioma of the external iliac vein: a primary vascular tumor presenting as traumatic venous obstruction.

A 32-year-old man employed as a laborer presented with the signs and symptoms of iliofemoral venous obstruction of 1 months' duration. Results of initial phlebography from the ankle to the femoral area were normal. No iliac vein anatomy was seen. This led to a group of tests directed toward neuromuscular function, which were unrewarding. On referral to our institution a noninvasive venous vascular laboratory examination was performed, which clearly indicated iliac vein obstruction/stenosis, with a normally patent distal venous system. Subsequent repeat phlebography, including direct femoral vein injection, visualized a mass lesion partially occluding the iliac vein. This lesion was treated with primary excision and segmental venous replacement with an interposition graft of autogeneous internal jugular vein. The excised lesion proved to be an epithelioid hemangioendothelioma of the iliac vein.

Adult↗
PubMed1989

Prevalence of hyperhomocyst(e)inemia in patients with peripheral arterial occlusive disease.

A micromethod adapted for automated determinations was used to measure basal plasma levels of homocyst(e)ine [H(e)]. These levels included the sum of free and bound forms of homocysteine, its disulfide oxidation product, homocystine, and the homocysteine-cysteine-mixed disulfide. Two groups of subjects were studied: apparently healthy individuals (n = 103) and patients with peripheral arterial occlusive disease (PAOD) (n = 47). Because age in PAOD patients was higher than in control subjects, the control subjects were subdivided into younger and older groups (aged 60 years or less and more than 60 years, respectively). The H(e) levels in the younger groups were 11.18 +/- 3.58 (mean +/- SD, expressed as homocysteine) and 8.58 +/- 2.82 nmol/ml in men and women, respectively; in the older groups, the levels were 10.74 +/- 2.16 and 9.04 +/- 2.16 nmol/ml in men and women, respectively. There was a positive correlation of H(e) levels with age in the younger control women (r = 0.373; p less than 0.02); no significant correlations were present in the other three control groups. Levels of H(e) in PAOD patients (15.44 +/- 5.76 and 17.04 +/- 8.26 nmol/ml in men and women, respectively) were significantly higher than those indicated above in the older controls. Next, the PAOD patients were assigned to two subgroups: 1) those with normal levels of H(e) (within two standard deviations of the mean of the control values) and 2) those with elevated levels of H(e). Age, cholesterolemia, and the prevalence of smoking and diabetes were similar in both subgroups. These results suggest that elevated plasma H(e) is an independent risk factor for arterial occlusive disease.

Age Factors↗
PubMed1989

Pathophysiological and parasitological studies on Ostertagia ostertagi infections in calves.

Friesian calves given a low level infection of the abomasal parasite Ostertagia ostertagi over a six week period displayed a mild diarrhoea with high faecal egg counts and elevated plasma pepsinogen values. At necropsy on day 23 abomasal lesions characteristic of ostertagiasis were widespread. At 42 and 84 days oedema and congestion were also prominent. Total worm burdens on days 23 and 42 were similar but a marked decrease had occurred by day 84. Feed digestibility and nitrogen economy were not markedly affected but radioisotopic measurements demonstrated an increase in albumin disappearance and catabolic rates, and plasma faecal clearance during the course of the infection. Prior administration of a morantel sustained release bolus to a group of similarly infected calves reduced the total worm burdens to less than 50 per cent of those recorded in the infected calves on days 23 and 42 and this fell to 3 per cent on day 84. Abomasal damage and the adverse pathophysiological changes associated with infection were prevented in this group.

Abomasum↗
PubMed1988

Limb salvage in end-stage renal disease (ESRD). Comparison of modern results in patients with and without ESRD.

We reviewed our experience with femoral-popliteal-tibial reversed vein bypasses performed for limb salvage in 226 patients without and 19 patients with end-stage renal disease (ESRD). While 18-month primary patency rates were comparable (85% and 89%), limb salvage was significantly lower (76% vs 95%) in patients with ESRD. Five amputations in the ESRD group were required for nonhealing, large foot ulcers in diabetic patients despite patent arterial bypass while only five of 13 amputations in patients without ESRD were required in the presence of patent grafts. The need for major amputation despite patent bypass in diabetic patients with ESRD who have extensive foot gangrene or ischemic ulceration occurs sufficiently often that we recommend primary amputation be considered in these patients without regard to possible vascular reconstruction.

Aged↗
PubMed1988

Treatment of infected abdominal aneurysms by extraanatomic bypass, aneurysm excision, and drainage.

Five patients with infected abdominal aortoiliac aneurysms were treated. The diagnosis was made preoperatively based upon fever, leukocytosis, positive blood culture findings, and presence of an aneurysm in all five patients. Two patients had salmonella species, two had staphylococcus species, and one had bacteroides species cultured from the blood and aneurysm contents. All patients were treated with appropriate antibiotics and a single operative procedure consisting of preliminary extraanatomic bypass followed by complete aneurysm excision and posterior drainage of the retroperitoneum. There were no operative deaths and no instances of aortic stump disruption, persistent retroperitoneal sepsis, or graft thrombosis. All patients were alive and well on last follow-up 15 months to 5 years postoperatively.

Aneurysm, Infected↗
PubMed1988

Vascular laboratory prediction of pedal pressure following femoropopliteal bypass.

This study examines the hypothesis that postoperative ankle-brachial pressure index (postop ABI) can be accurately predicted using noninvasive preoperative segmental leg pressure measurements. Seventy-three patients who underwent successful reverse autogenous vein femoropopliteal bypass and who had pre- and postoperative segmental leg pressure measurements were examined. Predicted postop ABI was estimated using the following formula: Postop ABI = 1 + (Preop ABI) - (Preop BKI). (BKI = below-knee brachial pressure index). Using this formula, 56 out of 73 (81%) patients had a measured postop ABI +/- 20% of predicted postop ABI. Five out of 73 (7%) patients had postop ABI less than 80% predicted, while 12 out of 73 (16%) patients had postop ABI greater than 120% of predicted. All patients with postop ABI greater than 120% of predicted had apparent tibial artery occlusive disease as indicated by preoperative gradients (BKI-ABI) greater than 0.15.

Anastomosis, Surgical↗
PubMed1988

The clinical course of carotid bifurcation stenosis as determined by duplex scanning.

Two hundred three patients had at least two carotid artery duplex (DS) examinations separated by at least 6 months (mean follow-up 18 months) and their risk factors, clinical outcome, and degree of carotid artery stenosis were compared. The accuracy of DS was established at greater than 90% by blinded comparison with angiography. During the study period 138 patients (68%) had stable carotid artery stenosis and 65 patients (32%) had progression of stenosis in at least one artery. Thirty patients had new symptoms of cerebrovascular disease (19 with transient ischemic attacks and 11 with stroke) during the study. It was not possible to predict which patients would become symptomatic on the basis of risk factor analysis or analysis of severity of stable carotid stenosis. Patients with progression of carotid artery stenosis to greater than 50% diameter reduction were significantly more likely (p less than 0.0001) to have new transient ischemic attack and stroke than were those with stable carotid artery stenosis, regardless of severity.

Adult↗
PubMed1988

Late-onset Raynaud's syndrome: diagnostic and therapeutic considerations.

A mild form of Raynaud's syndrome probably affects a significant percentage of the general population, apparently without serious sequelae. However, the patient with episodic digital ischemia who seeks medical attention is likely to have an identifiable associated disorder and a thorough evaluation is warranted. Autoimmune connective tissue disorder and atherosclerosis are the clinical conditions most frequently associated with Raynaud's syndrome. Conservative measures should be the mainstay of therapy.

Aged↗
PubMed1988

Congenital venous valvular aplasia of the lower extremities.

A 10-year-old girl had bilateral, symmetrical swelling of the lower extremities, which had been present since the age of 1 year. Noninvasive vascular laboratory measurements of the ambulatory venous pressure, venous recovery time, and maximum venous outflow revealed profound bilateral lower extremity venous valvular incompetence. Duplex imaging of the veins of the lower extremities demonstrated no evidence of thrombosis, and no venous valves could be imaged. On phlebography, the patient was found to have no venous valves in the superficial and deep systems of the leg. We conclude that congenital absence of the venous valves of the lower extremities is almost certainly underdiagnosed and that the vascular laboratory can accurately and easily differentiate between lymphedema and venous valvular imcompetence. Such differentiation may have therapeutic implications.

Child↗
PubMed1987

Buerger's disease in the modern era.

In an effort to determine the current incidence and clinical course of Buerger's disease, we reviewed the records of over 700 patients with small artery disease who were evaluated at Oregon Health Sciences University during a 15 year period. We identified 26 patients who met rigid criteria for the diagnosis of Buerger's disease. An analysis of the management and extended follow-up of these patients has indicated that Buerger's disease, although rare, is a real clinical entity which can be diagnosed objectively. The relatively high rate of limb loss (31 percent of patients) documents the virulence of Buerger's disease involving the lower extremities. No major upper extremity amputations were required, and no patient lost further tissue after cessation of smoking. These findings and the low mortality rate in this study stand in contrast to many previous reports and may aid in establishing the current natural history of Buerger's disease in North America.

Adolescent↗
PubMed1987

Autogenous reversed vein bypass for lower extremity ischemia in patients with absent or inadequate greater saphenous vein.

This report has presented the results of 329 reversed vein bypasses performed for lower extremity ischemia over a 6 3/4 year period. One hundred eighty-nine bypasses were formed from intact ipsilateral greater saphenous veins of adequate size and length. One hundred forty bypasses were formed in patients in whom the ipsilateral greater saphenous vein was absent or of inadequate size or length to complete the bypass. The grafts in these patients were accomplished using a variety of techniques including distal graft origin, use of arm veins and lesser saphenous veins, and use of vein splicing. The patency rates of these grafts were equivalent to those achieved using adequate intact ipsilateral greater saphenous vein. In view of these results, we conclude that the absence of a greater saphenous vein does not preclude successful autogenous lower extremity vein bypass and that prosthetic bypass is rarely justified.

Femoral Artery↗