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Biomedical subjects

W S Moore

Publications and source records attributed to W S Moore.

At least 163 records · Page 9Linked to original sources
PubMed1986

The superiority of synthetic arterial grafts over autologous veins in carotid-subclavian bypass.

From May 1964 to June 1983, 36 carotid-subclavian bypasses were done in 36 patients who had symptomatic lesions at the origin of the common carotid and/or subclavian arteries at the Center for Health Sciences of the University of California, Los Angeles. Ages ranged from 28 to 82 years (mean, 58 years). Eighteen bypasses were done with prosthetic grafts, 13 done with autogenous vein, and five were transpositions with primary anastomosis of the subclavian and carotid arteries. Follow-up was available on all patients and ranged from 9 to 156 months (mean, 51.5 months). The graft patency rate at 5 years determined by actuarial methods and documented by clinical examination, noninvasive evaluation, and/or arteriography was 94.1% for prosthetic grafts and 58.3% for vein grafts (p less than 0.01). The 5-year cerebrovascular accident (CVA) rate for patients with carotid-subclavian bypass done with prosthetic grafts was 6% in contrast to 39% for those with vein grafts (p less than 0.0545). All reconstructions done by transposition and primary anastomosis remain patent and there have been no late CVAs. We conclude that prosthetic grafts are the arterial substitute of choice in carotid-subclavian bypass. Transposition and primary anastomosis between the carotid and subclavian artery, when technically feasible, may be preferable to the use of free grafts in carotid-subclavian reconstruction.

Actuarial Analysis↗
PubMed1986

Intraoperative fibrinolytic therapy: experimental evaluation.

Percutaneous intra-arterial infusion of fibrinolytic agents has emerged as an alternative to embolectomy in selected patients with acute arterial occlusions. The combination of fibrinolytic therapy and embolectomy may be superior to either modality alone. This experiment was designed to determine safety and efficacy of intraoperative fibrinolytic therapy as an adjunct to catheter embolectomy. Forty hind limbs in 20 adult mongrel dogs were embolized with thrombus created in vitro. After 24 hours, bilateral transfemoral embolectomy was followed by intra-arterial, intraoperative infusion. Fifteen limbs (control) received 250 ml of saline solution during a 30-minute period; 25 limbs (experimental) received an arterial infusion of 60,000 units of streptokinase during a 30-minute period (SK 30'). In five limbs of each group, 500 units of heparin (H) was added. In five experimental limbs the streptokinase infusion time was increased to 60 minutes (SK 60'). Arteriograms and blood flow measurements were obtained before and after embolectomy (PE) and after infusion (PI); the results were compared. Improvement between the PE and PI angiograms was seen in 20% (3 of 15 dogs) of control subjects. In contrast, improvement after the infusion was evident in 100% (5 of 5 dogs) of dogs given SK plus H 30' (p less than 0.01), in 80% (12 of 15 dogs) of dogs given SK 30' (p less than 0.01), and in 20% (1 of 5 dogs) of dogs given SK 60'. A trend toward increased blood flow was noted in the experimental group. There were no intraoperative complications with hemostasis or postoperative bleeding (36-hour observation). We conclude that intraoperative fibrinolytic therapy in dogs is safe and effective as an adjunct to thromboembolectomy. A human clinical trial is recommended.

Animals↗
PubMed1985

The placing of many large superconducting magnets in a limited space.

The problem of minimizing the space needed to house two or three superconducting magnets was studied. Dipolar fields were used to approximate the stray fields. Field contours of a single dipole mu are reviewed. The three-dimensional contour surface is discussed in terms of its intersection with planes parallel to a base plane containing mu. The area within a field contour H in the base plane was numerically determined to be 142.55 m2[(mu/mu 0)(H0/H)]2/3 where mu 0 = 10(9) erg/G and H0 = 5 G. For the contours within planes parallel to the base plane, the contour area and its intercepts with the planar x and y axes are given as a function of the distance from the base plane. For two dipoles at one site and for a given mechanical stress, the torque-free orientations allow closer spacing. Field contours for the four torque-free orientations are given for mu 1 = mu 2. For one zero-torque configuration (mu 1 and mu 2 antiparallel, but perpendicular to the line joining them) and for a mutual force of 667 N (150 lb), the 5-G contour area is only 36% greater than that for a single dipole. General expressions for the forces, torques, and field gradients for two dipoles are given. Torque-free cases of three superconducting magnets (two of which are identical) at one site are described. Contour plots of the linear arrangements of the magnets as well as of two symmetrical triangular arrangements (corner angle is either 70.5 or 109.5 degrees) are given.

Equipment Safety↗
PubMed1985

Radiological sampling and analytical methods for National Primary Drinking Water Regulations.

Radiological sampling and analysis performed under the National Interim Primary Drinking Water Regulations were evaluated for the U.S. Environmental Protection Agency (EPA) Office of Drinking Water to consider whether any changes should be recommended. The authors reviewed the analytical screening scheme; sample collection, storage and analysis procedures; selection of analytical methods; reliability of results; and possible future needs. The main problem in the program has been dependence on a screening scheme of gross alpha-particle activity measurement and 226Ra analysis for predicting elevated 228Ra levels to determine compliance with the maximum contaminant level (MCL) for Ra. In some aquifers, 228Ra levels have been found to be unrelated to 226Ra levels. Several alternatives are discussed to eliminate this problem. A secondary problem is that the measurement for assuring compliance with the MCL for gross alpha-particle activity minus Ra, Rn and U uses chemical U analysis and assumes equilibrium of 238U and 234U. Because some ground waters are known to be at disequilibrium, radiometric U analysis is needed for those gross alpha-particle activities and chemical U values that could result in an erroneous conclusion relative to the MCL. In addition, studies were recommended for determining analytical uncertainties and assuring reliable sampling and sample maintenance; improvements in the system for accepting methods were suggested; and methods were identified for several radionuclides not currently in the analytical program that may be needed to assure absence of elevated radiation doses and could be useful for identifying trace contaminants.

Alpha Particles↗
PubMed1985

Acute renal dysfunction after major arteriography.

The incidence of acute renal dysfunction (ARD) after major arteriography was evaluated by assessment of the change in serum creatinine in 364 patients undergoing arteriography. Major arteriography was defined as abdominal aortography, abdominal aortography with lower-extremity runoff, aortic arch studies, or aortic arch plus selective carotid angiography. The influence of the volume of contrast material received, hydration, and associated risk factors was evaluated. In the entire group, the frequency of postarteriographic ARD was 7.1%. Although most patients recovered, 1.4% required renal dialysis. The frequency of renal dysfunction was significantly higher in patients with preexisting renal disease (14.8%), and 3.7% of these patients went on to require dialysis. In the total group and in those with normal renal function prearteriographically, the frequency of ARD was found to be related to the volume of iodinated contrast material received. Hydration before, during, and after angiography did not prevent this complication. Several risk factors, namely preexisting renal disease, advanced age, volume of contrast material used, type of study performed, diabetes mellitus, and coexistent heart disease were found to be associated with a statistically significant increased risk of postangiographic ARD.

Acute Kidney Injury↗
PubMed1984

Polytetrafluoroethylene grafts as the first-choice arterial substitute in femoropopliteal revascularization.

We studied a series of femoropopliteal bypass operations in which polytetrafluoroethylene (PTFE) grafts were used as the first choice, regardless of the availability of saphenous vein. From Jan 1, 1979 to Dec 31, 1982, 63 PTFE femoropopliteal bypass grafts were placed in 55 patients without exploration of the saphenous vein. Forty-three grafts were placed for limb salvage, and 20 grafts were placed for disabling claudication. Patients were followed up for nine to 53 months (average, 23 months). The operative mortality was 1.8%. There were no infections. The overall patency at 30 months was 76.1%. The 30 months' cumulative patency rate for patients with claudication was 89.3%, and there were no amputations. The cumulative 30-month patency for limb salvage was 70.1%, and there was a limb salvage rate of 81.2%. Because the 30-month results were comparable with reported series using autogenous saphenous vein, we concluded that PTFE conduits may be considered the first-choice arterial substitute for femoropopliteal reconstruction. Until longer follow-ups are available, reversed autogenous saphenous vein should probably be the graft of first choice in younger patients (less than 60 years of age) without coronary artery disease who are undergoing femoropopliteal revascularizations.

Aged↗
PubMed1984

Determinants of failure in the treatment of ruptured abdominal aortic aneurysm.

One must identify those fatal errors in the treatment of patients with ruptured abdominal aortic aneurysms (AAAs) to improve future treatment and reduce mortality. Our vascular registry identified 29 patients with ruptured AAAs who died following admission to the UCLA Hospital, Los Angeles, and the Sepulveda (Calif) Veterans Administration Hospital between 1971 and 1981. Review of the records identified four categories of error that contributed to death. These included failure to proceed with elective aneurysmectomy in 12 patients with known AAAs, error in the diagnosis of aortic rupture that led to delay in getting nine patients to the operating room, intraoperative technical error that produced venous injury in eight patients, and undue delay in anesthetic induction in four patients. Following the outline of a careful treatment approach should further reduce the mortality in the treatment of patients with ruptured AAAs.

Aged↗
PubMed1984

Intravenous labetalol in the management of severe hypertension and hypertensive emergencies.

The intravenous administration of labetalol, a combined alpha- and beta-adrenergic receptor blocking agent, reduced diastolic blood pressure by 30 mm Hg or more in 15 of 17 patients with severe hypertension (supine diastolic blood pressure greater than or equal to 125 mm Hg). A method repeated intravenous injection of the drug produced a prompt but gradual reduction of arterial blood pressure without the induction of a reflex tachycardia. Side effects were mild and of brief duration despite the presence of hypertensive complications in many of these patients. Hypotension, coronary insufficiency, or neurologic deterioration did not occur. Labetalol appears to be a suitable alternative to the direct vasodilating agents in the management of patients with severe hypertension and hypertensive emergencies.

Adolescent↗
PubMed1984

The use of nuclear magnetic resonance in the diagnosis of lateral canal entrapment.

The use of nuclear magnetic resonance (NMR) in the diagnosis of radicular pain due to lateral canal stenosis in 21 patients is reported. NMR was able to distinguish normal intervertebral discs from degenerate discs, and NMR evidence of reduction of epidural fat was more reliable than radiculography in identifying lateral root entrapment. NMR is an important advance in the investigation of lumbar radiculopathies.

Adult↗
PubMed1984

The efficacy of dextran 40 in preventing early postoperative thrombosis following difficult lower extremity bypass.

In a randomized, multicenter trial the efficacy of intravenous dextran 40 (D-40; Rheomacrodex) in preventing early postoperative thrombosis was tested in the following difficult lower extremity bypasses: (1) femoropopliteal with poor runoff using autologous vein (AV), (2) femoropopliteal using grafts other than AV, (3) single or sequential bypasses to infrapopliteal arteries, and (4) the above-mentioned bypasses with adjunctive procedures that destroy adjacent endothelial surfaces (e.g., thrombectomy and endarterectomy). Five units of D-40 was administered to the experimental group at 75 to 100 ml/hr, two during and immediately after operation and one each 3 days postoperatively. Antiplatelet drugs were withheld until 1 week after surgery. The overall 1-week occlusion rate was 6.9% (5 of 73) with D-40 and 20.5% (17 of 83) for controls, which is statistically significant. Particularly significant was the difference in group 3: 0% (0 of 28) for D-40 and 27.8% (10 of 36) for controls. In the same time period there were no occlusions in group I and only one occlusion each with AV grafts in both D-40 and control groups, 2.6% (1 of 38). When grafts other than AV were used, the occlusion rate was significantly lower at 1 week for D-40, 11.4% (4 of 35), than controls, 35.6% (16 of 45). By 1 month the protective effect of D-40 was partially lost--15.3% (11 of 72) for D-40 and 20.7% (17 of 82) for controls (no statistical significance). Use of antiplatelet drugs during this period had no discernible effect.

Blood Vessel Prosthesis↗
PubMed1984

Bacteriologic and surgical determinants of survival in patients with mycotic aneurysms.

Mycotic aneurysms are a fulminant infectious process frequently resulting in rupture and death if not properly treated. A review of the University of California, Los Angeles, medical records identified 10 patients with extrathoracic, extracranial mycotic aneurysms. In addition, a search of the English literature revealed 178 patients with 243 mycotic aneurysms. These patients were reviewed to identify the aneurysm location, etiology, bacteriology, and modality of treatment in order to determine the relationship between these factors and the outcome. The femoral artery was the most common site (38%), followed by the abdominal aorta (31%). Arterial trauma was the primary etiology in 42% of mycotic aneurysms. In 25% no clear source of infection could be identified. Staphylococcus aureus was cultured from 28% of mycotic aneurysms, and Salmonella from 15%. A trend toward the involvement of more gram-negative aerobes and anaerobes is noted. Aortic aneurysms were repaired with in situ Dacron in 61% of patients with a 32% mortality rate and 16% reinfection rate. Simple ligation of femoral artery mycotic aneurysms resulted in a 34% incidence of ischemia necessitating amputation. Methods of treatment of superior mesenteric, carotid, iliac, and peripheral arteries are also analyzed. On the basis of these data, specific surgical procedures are recommended for the treatment of mycotic aneurysms.

Adolescent↗
PubMed1984

The limitations of predictability of success of femoral-popliteal bypass grafts.

This study was carried out to determine whether we could develop a model to identify predictive factors for success of femoral-popliteal (FP) bypass grafts. In a retrospective review of 199 operations, 24 factors influencing outcome were selected by stepwise logistic regression analysis, a sophisticated, multifactorial computer program. The top five indicators (excluding intraoperative technical problems) were runoff status, previous ipsilateral FP bypass, preoperative prediction of potential amputation level, concurrent proximal vascular reconstruction, and site of the distal anastomosis. We chose to validate the predictive model developed before applying it clinically. Data from 67 subsequent cases were presented to the computer without the known outcome, and the probability of 30-day patency was calculated. The model predicted 11 failures; there were actually eight thromboses in the 67 grafts. However, only three of the failures were predicted correctly, and eight cases of computer-anticipated thromboses were patent at 30 days. The high false positive rate makes the clinical application of the predictive model inappropriate. The success of FP bypass grafts appears to be related to factors that cannot be assessed preoperatively, such as technical problems during surgery. Even those which seem to have a poor runoff and other high-risk factors may succeed; thus an aggressive approach is justified in lower extremity reconstructions.

Blood Vessel Prosthesis↗
PubMed1983

Congenital arteriovenous malformations. The role of transcatheter arterial embolization.

We treated 11 patients with congenital arteriovenous malformations (AVMs) with staged transcatheter arterial embolization of their lesions. In nine patients, the AVM involved an extremity. One patient had multiple pulmonary AVMs, another an AVM of the pancreas. Embolization was performed using polyvinyl alcohol sponge (Ivalon) particles and Gianturco-Wallace colls. Nine patients had a systemic response to embolization, characterized by pain, fever, leukocytosis, and elevated enzyme levels. Complications (three major, two minor) developed in five patients. A total of 28 staged embolizations were performed, with follow-up to 36 months. We found transcatheter embolization a useful palliative therapy in treating congenital AVMs. It should be considered as a therapeutic alternative for patients with unresectable AVMs, those for whom amputation would be required, and those who are otherwise poor surgical candidates.

Adolescent↗
PubMed1983

Risk of renal failure after major angiography.

In 400 patients who underwent major aortography, acute renal dysfunction (ARD) occurred in 11.3%. Of the group with normal renal function before the procedure, 8.2% had ARD and 0.8% required dialysis. Patients with prior abnormal renal function had a 41.7% incidence of ARD, and 8.3% required dialysis as a result of angiography. Vigorous intravenous hydration was used in all patients but did not completely prevent renal problems. Two risk factors not previously emphasized were the injection site (higher risk with abdominal aortic studies) and presence of congestive heart failure requiring treatment with digoxin. Other notable risk factors included contrast load and age. These results emphasized that even with modern contrast agents and application of current concepts of treatment, there remains a risk of renal injury with major angiography.

Acute Kidney Injury↗
PubMed1983

Anticytoplasmic antibodies in antinuclear antibody-negative lupus erythematosus. Correlation with clinical course.

A patient with clinical manifestations of systemic lupus erythematosus (SLE) and without antinuclear antibodies was found to have anticytoplasmic antibodies. These anticytoplasmic antibodies were directed against ribosomal ribonucleoprotein, and the titer of anticytoplasmic and anti-ribosomal ribonucleoprotein antibodies correlated with the clinical course of the patient's illness. The importance of detecting anticytoplasmic antibodies and their role in producing disease in patients with SLE is discussed.

Adolescent↗