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Biomedical subjects

W S Moore

Publications and source records attributed to W S Moore.

At least 55 records · Page 3Linked to original sources
PubMed1998

Dexamethasone and enalapril suppress intimal hyperplasia individually but have no synergistic effect.

Vascular injury is associated with complex interactions that lead to development of intimal hyperplasia (IH). We have demonstrated previously that the corticosteroid dexamethasone and the ACE-inhibitor enalapril are effective in suppressing the development of IH. We hypothesize that due to distinctly different pharmacologic mechanisms of action, a synergistic effect would be expected if these agents were given in combination. Forty New Zealand White rabbits underwent balloon catheter denudation of the carotid artery. Animals were divided into four equal treatment groups and received daily intramuscular injections: Group 1, saline; Group 2, enalapril 0.07 mg/kg, Group 3, dexamethasone 0.125 mg/kg; and Group 4, enalapril 0.07 mg/kg plus dexamethasone 0.125 mg/kg. Vessels were harvested at 12 weeks and intimal hyperplasia was measured as a ratio of the absolute area of IH to the normalized area enclosed by the internal elastic lamina (IH/IEL). Mean values for IH/IEL are expressed as a percent (SD): Group 1, 32.31 (14.9); Group 2, 9.47 (2.11); Group 3, 5.40 (4.14); and Group 4, 8.49 (4.27). All treatment groups demonstrated significant suppression of IH compared to the control group (p < 0.01); dexamethasone was more effective than enalapril (p = 0.01). There was no statistical difference in IH suppression between respective agents and the combination group (p > 0.10). Coadministration of dexamethasone and enalapril provides no advantage over single-agent therapy in suppressing the development of IH, suggesting that maximal suppression is obtained with single-agent treatment or that these agents affect IH through a common pathway.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1998

Clinical consequences of periprosthetic leak after endovascular repair of abdominal aortic aneurysm. Endovascular Technologies Investigators.

PURPOSE: The study was conducted to evaluate risk factors, natural history, and clinical consequences of a periprosthetic leak after endovascular repair of an abdominal aortic aneurysm. METHODS: We reviewed the initial and follow-up data, including angiograms, contrast-enhanced computed tomography (CT) scans, abdominal duplex scans, and plain abdominal films for all patients undergoing tube graft repair using the endovascular graft system (early prototype) between February 10, 1993, and January 24, 1995. RESULTS: Sixty-eight patients underwent placement or attempted placement of a tube graft implant in 13 centers in the United States. Nine patients required conversion to open repair, leaving 59 patients with functioning grafts for evaluation. The mean follow-up time was 27 +/- 8 months (range, 2 to 48 months). Twenty-eight (47%) of 59 patients had initial periprosthetic leaks (6 proximal, 14 distal, 3 proximal and distal, 5 indeterminate) on their first postoperative CT scans. Fourteen (50%) of the initial 28 leaks sealed spontaneously. Two other patients had their leaks sealed by endovascular means, leaving 12 patients with persistent leaks for follow-up evaluation. Four patients developed late leaks between 18 and 24 months of follow-up: one who had a spontaneously sealed initial leak, one with a second leak, and two who developed late leaks. Of the 16 patients with sealed leaks, 10 had aneurysm size reduction during follow-up. Three aneurysm sacs enlarged before spontaneous sealing but have not had sufficient follow-up time to document the size change since the seal. One patient died of respiratory failure 5 months after graft implantation. One patient whose leak was sealed by intervention has not yet had a CT scan for evaluation. In one patient with a sealed leak and whose aneurysm had initially shrunk, the area reopened and progressed to a nonfatal rupture that was surgically corrected. There were two late deaths from unrelated causes. Twelve patients in the sealed group are alive and well. Of the 12 patients with persistent leaks, five underwent open surgical repair without complication, and one underwent successful endovascular repair with a second graft. Six patients continue to live with their initial grafts and have an average aneurysm sac enlargement of 0.1 cm per year. CONCLUSIONS: Although initial periprosthetic leaks were common with the use of this early prototype, 50% spontaneously sealed. The subsequent clinical course of patients with persistently sealed leaks was no different from that of patients who had no leaks. However, continued CT surveillance is warranted, because in one patient with an initially sealed leak, the area reopened and progressed to nonfatal rupture. Another two patients without initial leaks developed late leaks. In a small group of selected patients with continued leaks, their aneurysms appeared to enlarge at a rate considerably slower than would have been expected in patients with untreated aneurysm, suggesting that even a person after endovascular repair with a persistent leak may have had some beneficial hemodynamic modification.

Aged↗
PubMed1998

A diagnostic comparison of panoramic and intraoral radiographs.

OBJECTIVE: This study compared panoramic and intraoral radiographic surveys in the evaluation of specific dental pathoses in Air Force personnel. STUDY DESIGN: The radiographs of 30 subjects were read singly and in various combinations: panoramic survey only; periapicals plus bitewings; panoramic survey plus bitewings; and panoramic survey plus periapicals plus bitewings. Three independent, blinded examiners using standardized viewing conditions assessed the radiographs in random order for the presence of caries, periapical pathoses, bone loss, furcation involvement, impacted/unerupted teeth, internal/external root resorption, and retained roots. The consensus radiographic standard of true pathosis was the simultaneous interpretation by the three examiners of all radiographs for each subject. RESULTS AND CONCLUSIONS: The panoramic survey by itself was shown to have the lowest correlation with the consensus radiographic standard when basic military trainees with generalized dental pathoses were evaluated. The combination of panoramic survey plus bitewing radiographs exhibited a diagnostic yield for specific pathoses that was comparable to that of panoramic survey plus bitewings plus periapicals.

Adolescent↗
PubMed1998

A perceptibility curve comparison of Ultra-speed and Ektaspeed Plus films.

OBJECTIVE: The purpose of this study was to evaluate the subjectively assessed contrast difference between Kodak's Ultra-speed and Ektaspeed Plus dental radiography films (Eastman Kodak, Rochester, N.Y.) through the use of perceptibility curves. DESIGN: Four series of 22 radiographs were exposed at 70 and 90 kVp with each film type by means of a Gendex 1000 dental radiography unit (Gendex Corp., Milwaukee, Wis.) for times ranging from 0.05 to 5 seconds at 10 ma. The test object consisted of a 7-mm-thick rectangular aluminum block with 10 circular depth cuts, each 2 mm in diameter, which created wells varying in depth from 50 to 500 microns. The corresponding films were processed concurrently (for 4.5 minutes) in total darkness with fresh Kodak Readymatic solutions (Eastman Kodak) held at a constant temperature of 28 degrees C. The resulting radiographs were viewed in a predetermined random order under ideal conditions by 10 dentists. The evaluators recorded the maximum number of perceptible images on each film. A pair of perceptibility curves were generated at 70 and 90 kVp by plotting the log relative exposure versus the mean number of perceptible images. RESULTS: There was no statistical difference between the two film types with respect to the mean number of perceptible images, as analyzed by Wilcoxon's signed rank test (p = 0.22; p = 0.44). CONCLUSIONS: There is no subjectively assessed contrast difference between Kodak s Ultra-speed and Ektaspeed Plus films at 70 and 90 kVp.

Absorptiometry, Photon↗
PubMed1998

Recurrent carotid stenosis : results of the asymptomatic carotid atherosclerosis study.

BACKGROUND AND PURPOSE: We sought to determine the incidence of recurrent carotid stenosis in patients in the Asymptomatic Carotid Atherosclerosis Study (ACAS) who had undergone carotid endarterectomy and were prospectively followed with Doppler ultrasound for up to 5 years. METHODS: The ACAS database was interrogated to determine the rate of recurrent carotid stenosis (>/=60%) based up angiogram-validated Doppler data, with a 90% and a 95% positive predictive value, as well as information concerning the technologists' interpretation of percent stenosis. These 3 parameters are reported for each of 3 time intervals: within 3 months of operation (residual disease), between 3 and 18 months (early restenoses), and between 18 and 60 months (late restenosis). RESULTS: Of the 825 patients randomized to the surgical arm of the study, 720 actually underwent carotid endarterectomy, and 645 had complete ultrasound data. The aggregate incidence of residual and recurrent carotid stenosis for all time intervals ranged from 12.7% to 20.4%, depending on the positive predictive value confidence level desired. Residual disease occurred in 4.1% to 6.5%; true, early restenosis was found in 7.6% to 11.4%; and late restenosis occurred in 1.9% to 4.9%. None of the traditional risk factors showed a statistically significant effect on recurrent stenosis. The use of patch angioplasty closure reduced overall risk of restenosis from 21.2% to 7.1%, from 16.7% to 4.6%, and from 27.4% to 8.2%, depending on the PPV confidence level desired (P<0.001). Of the 136 patients judged to have recurrent stenosis, only 8 (5.9%) underwent reoperation (only 1 for symptoms). There was no correlation between late stroke and recurrent stenosis. CONCLUSIONS: Carotid endarterectomy is a durable procedure with a low rate of true restenosis, particularly when patch angioplasty is used to close the arteriotomy.

Angioplasty↗
PubMed1997

The utility of DNA sequences of an intron from the beta-fibrinogen gene in phylogenetic analysis of woodpeckers (Aves: Picidae).

Estimating phylogenies from DNA sequence data has become the major methodology of molecular phylogenetics. To date, molecular phylogenetics of the vertebrates has been very dependent on mtDNA, but studies involving mtDNA are limited because the several genes comprising the mt-genome are inherited as a single linkage group. The only apparent solution to this problem is to sequence additional genes, each representing a distinct linkage group, so that the resultant gene trees provide independent estimates of the species tree. There exists the need to find novel gene sequences which contain enough phylogenetic information to resolve relationships between closely related species. A possible source is the nuclear-encoded introns, because they evolve more rapidly than exons. We designed primers to amplify and sequence the 7 intron from the beta-fibrinogen gene for a recently evolved group, the woodpeckers. We sequenced the entire intron for 10 specimens representing five species. Nucleotide substitutions are randomly distributed along the length of the intron, suggesting selective neutrality. A preliminary analysis indicates that the phylogenetic signal in the intron is as strong as that in the mitochondrial encoded cytochrome b (cyt b) gene. The topology of the beta-fibrinogen tree is identical to that of the cyt b tree. This analysis demonstrates the ability of the 7 intron of beta-fibrinogen to provide well resolved, independent gene trees for recently evolved groups and establishes it as a source of sequences to be used in other phylogenetic studies.

Animals↗
PubMed1997

Rupture of the perivisceral aorta: atherosclerotic versus mycotic aneurysm.

Twelve patients with rupture of the perivisceral abdominal aorta were admitted to the UCLA Medical Center between 1984 and 1996. Six patients had atherosclerotic thoracoabdominal aneurysms (TAA) which ruptured in the visceral segment of the aorta. The remaining 6 patients proved to have ruptured mycotic aneurysm (MA). Clinical presentation was different in the two groups. Whereas all 6 patients with TAA and < 24 hr history of abdominal, chest, or back pain, patients with MA had these symptoms for 2-5 weeks (mean 3.4 weeks). History of sepsis was present in 4/6 MA and in 0/6 TAA patients. No difference in risk factors for atherosclerosis were seen between these two groups. Clinical outcomes were also different. Operation consisted of in situ vascular grafting in all patients. Operative mortality for TAA was 33% (2/6), whereas all patients with MA survived repair with no operative mortality. Two patients had cardiac arrest prior to surgery. One of these had a TAA and died 5 days after surgery, whereas the other survived repair of an MA. Follow-up ranges from 1-84 months (mean 48 months). Four survivors in the TAA group are alive at 6, 8, 14, and 84 months, with the latter having a pseudoaneurysm of the visceral patch-graft anastomosis. All 6 patients with MA are alive at 1-73 months (mean 39 months) without evidence of graft sepsis or recurrent aneurysm. We conclude that rupture of the visceral portion of the aorta is often associated with a mycotic process, with important differences noted in clinical presentation when compared to atherosclerotic TAA. Surgical intervention is effective in both MA and TAA. Operative mortality, however, is significantly higher in patients with ruptured TAA. In situ prosthetic replacement for ruptured MA is associated with low mortality and excellent long-term results.

Aged↗
PubMed1997

Use of the in-situ lesser saphenous vein bypass from popliteal to peroneal artery.

Lesser saphenous vein grafts have become an important element in limb salvage surgery. Their location frequently dictates that the graft be translocated for use. This incurs the disadvantages of ischemia and increased manipulation of the graft and loses the advantages of an in-situ bypass. The use of the lesser saphenous vein as an in-situ graft for tibial artery reconstruction offers the advantages of reduced vein graft injury and improved patency. Technical requirements for an in-situ lesser saphenous bypass include that graft inflow be based on the popliteal artery, the vein length suffice to reach the target artery, and the runoff vessel have adequate size, length, and collateral connections to allow reasonable likelihood of success. The surgical approach requires the patient be in a prone position allowing a posterior longitudinal incision in the leg. Exposure of the distal portion of the peroneal artery is accomplished by separating the peroneus brevis and flexor hallucis longus. The peroneal artery is then visualized when the fibular attachments of the flexor hallucis longus are divided. Our experience indicates that the lesser saphenous vein may be successfully used as an in-situ conduit for bypass to the distal peroneal artery. Technical innovations such as flexible valvulotomes with detachable heads, and tourniquet control of bleeding facilitate the operation. A posterior approach to the popliteal and crural arteries affords the ability to use the lesser saphenous vein as an in-situ bypass.

Aged↗
PubMed1997

The EVT tube and bifurcated endograft systems: technical considerations and clinical summary. EVI Investigators.

Endovascular exclusion of abdominal aortic aneurysms (AAAs) is an investigational technique under scrutiny around the world. The tube and bifurcated versions of the Endovascular Grafting System (EGS) developed by Endovascular Technologies are the subjects of FDA-approved multicenter trials in the United States (US). Similar studies are under way in Europe, Australia, and the United Kingdom. This review details the implantation techniques for the EGS device and summarizes the important clinical findings published through 1996. Although the EGS was voluntarily removed from the US trial when fractures were discovered in the graft attachment system, subsequent experience with the re-engineered EGS has been positive. Successfully implanted EGS tube grafts have been associated with aneurysm shrinkage after 1 year in AAAs initially excluded or with sealed endoleaks. Aneurysm enlargement has been seen in EGS tube grafts with persistent endoleak.

Aortic Aneurysm, Abdominal↗
PubMed1997

Transluminal balloon angioplasty, stents, and atherectomy.

Arterial bypass grafting for occlusive disease is still considered the gold standard in the treatment of arterial occlusive disease. However, less invasive methods are available for select patients. Percutaneous balloon angioplasty has been shown to be effective in focal iliac artery stenosis, with patency rates of 50% to 90% at 5 years. Patency rates for femoropopliteal lesions are generally less than 50% at 2 years. Complications seen with balloon angioplasty often can be treated with arterial stents. Stents can be categorized into balloon-expandable, which provide a rigid scaffold to support the artery, self-expanding, which exert radial force to resist external compression, and thermal expanding stents, which allow for the use of a smaller introducer sheath. Another treatment option is atherectomy, in which the offending lesion is removed instead of fracturing and dilating the lumen. Although overall initial results of atherectomy have not been favorable, short lesions with eccentric atheroma or intimal hyperplasia, such as those seen in dialysis access fistulas or vein graft stenoses, may respond well.

Angioplasty, Balloon↗
PubMed1996

The effect of vitamin E and doxycycline on the development of intimal hyperplasia.

The goal of this study is to evaluate the influence of vitamin E (alpha-tocopherol) and doxycycline on the development of intimal hyperplasia in the injured rabbit carotid artery. Three groups of New Zealand white rabbits (10 rabbits each) underwent standardized balloon catheter injury of the carotid artery. One group received 300-400 U/kg of vitamin E orally each day for 4 weeks; another group received 10 mg/kg of doxycycline orally twice daily for 4 weeks and the final group remained as a control group. No statistically significant differences in the degree of intimal hyperplasia development were noted between either treatment group and controls (P > 0.60 for vitamin E, P > 0.40 for doxycycline). We conclude that neither vitamin E nor doxycycline appear to be of benefit in reducing intimal hyperplasia in the injured rabbit carotid artery.

Angioplasty, Balloon↗
PubMed1996

A phylogeny for the African treefrog family Hyperoliidae based on mitochondrial rDNA.

Mitochondrial 12S rRNA sequences were used to construct a phylogeny for the African treefrog family, Hyperoliidae. The sequences were aligned using the well-established mt 12S rRNA secondary structure as a map to designate stem and loop positions. Conservation of secondary structure permits a more accurate basis for assessing homologies than does primary sequence alone. The molecular trees showed many similarities to the morphological trees constructed previously. Species within a genus always grouped together. The genera Hyperolius, Heterixalus, Afrixalus, and Kassina were resolved, but not with statistical significance. Leptopelis was the basal group. The analysis shows clearly that Phylyctimantis groups with Kassina as it did in Drewes' morphological tree and that Tachycnemis groups closely with Heterisxalus, a relationship not suggested by the morphological data. Character weighting (including compensatory base changes), mitochondrial trees vs gene trees, and the biogeography of the group are discussed.

Africa↗
PubMed1996

Intraoperative vascular endoscopy: early and late results.

In a prospective study, 60 consecutive cases of vascular endoscopy were analyzed to examine the role of angioscopy in infrainguinal vascular procedures. A total of 52 patients had 60 separate vascular endoscopy procedures performed as an adjunct to various vascular procedures; results of intraoperative arteriography were available in 38 of 60 cases. All patients were followed for at least 42 months. The 19 patients who underwent thrombectomy with angioscopy were compared with 19 age-matched control subjects who underwent infrainguinal thrombectomy without angioscopy to evaluate the influence of angioscopy on primary and secondary patency rates. Angioscopy allowed observation of 50 lesions; angiography failed to detect three. These findings altered surgical management in 24 cases (40%). Primary patency rates for the control and experimental thrombectomy groups were 38.8% and 6.5% at 42 months, respectively (p = 0.010 based on log-rank test). Secondary patency rates for the control and experimental groups at 42 months were 63.8% and 49%, respectively (p = 0.521). The limb salvage rate was 89% at 42 months for both groups (p = 0.973). Angioscopy provides the clinician with a direct view while he or she is performing vascular procedures. However, there was no statistical improvement in secondary patency and limb salvage rates. Furthermore, the use of angioscopy during thrombectomy may increase the propensity for subsequent intervention as evidenced by the frequency of changes in surgical management and the lower primary patency rate.

Adolescent↗
PubMed1996

Vascular surgery in the United States: workforce issues. Report of the Society for Vascular Surgery and the International Society for Cardiovascular Surgery, North American Chapter, Committee on Workforce Issues.

The Committee on Workforce Issues of the Society for Vascular Surgery (SVS) and the North American Chapter, International Society for Cardiovascular Surgery (NA-ISCVS) generated data on the numbers and trends of operations performed and workforce requirements to provide surgical care of patients with vascular disease. Data for analysis were obtained from The National Center for Health Statistics-National Hospital Discharge Survey and questionnaires sent to 2732 vascular surgeons. The data showed that SVS/NA-ISCVS and regional vascular society (RVS) surgeons performed 51% of 583,000 vascular procedures undertaken in the United States in 1992. This represents a 24% increase over the 41% reported in 1985 by similarly defined surgeons. Analysis of 1992 index cases documented that SVS/NA-ISCVS and RVS surgeons accounted for 80% of 31,000 aortoiliofemoral bypasses, 68% of 46,000 aortic aneurysmectomies, 64% of 91,000 carotid endarterectomies, and 72% of 98,000 angioaccess procedures. The mean numbers of vascular operations performed in 1992 by SVS/NA-ISCVS and RVS surgeons were 144 and 100, respectively. These procedures represented 64% and 39% of the total surgical caseload of SVS/NA-ISCVS and RVS surgeons, respectively. American Board of Surgery (ABS)-certified vascular surgeons performed a mean of 171 vascular operations in 1992. Other surgeons, including ABS-certified general surgeons, appear to be performing fewer vascular operations. The latter fact and the increasing incidence of vascular disease in an expanding elderly population supports a continued need for vascular surgery specialists. Evolving technology and new health care delivery systems, however, may lessen the need for surgical care of these patients. Continued assessments of workforce activity will allow better definition of changing vascular surgery needs.

Humans↗
PubMed1996

Surgical results: a justification of the surgeon selection process for the ACAS trial. The ACAS Investigators.

PURPOSE: The selection of surgeons to participate in a prospective randomized trial comparing the efficacy of a surgical method with medical management is critically important because it will have a direct impact on the outcome of the study and the future use of the operation. We report the success of the method used for selecting surgeons who participated in the Asymptomatic Carotid Atherosclerosis Study (ACAS) by examining the surgical morbidity and mortality rates and the outcome of the study. METHODS: A Surgical Management Committee established criteria for auditing surgeons who wished to participate in the study. The parameters included a minimum performance of at least 12 carotid endarterectomies (CEA) per year and an audit of each surgeon's last 50 consecutive CEAs with required documentation of a combined neurologic morbidity and mortality rate of <3.0% for asymptomatic patients and <5.0% for all indications including symptomatic patients. RESULTS: As of February 1991, 164 surgeons from 48 medical centers applied for ACAS participation. One hundred seventeen were approved, and their aggregate experience of 5641 operations yielded a combined neurologic morbidity and mortality rate of 2.3% for asymptomatic and symptomatic patients combined. The morbidity and mortality rate for CEA on asymptomatic patients was 1.7%. These surgeons, plus those recruited after February 1991, became investigators in the ACAS trial and were responsible for the surgical care of 825 patients who were randomized to the surgical arm. Seven hundred twenty-four patients actually underwent CEA. One patient (0.14%) died and ten patients (1.38%) had strokes within the 30-day perioperative interval, for a combined stroke or death incidence of 1.52%. The 5-year stroke event rate in the surgical group (including perioperative morbidity and mortality rates) was 5.1%. compared with 11% of patients treated medically, yielding a relative risk reduction of 53% in favor of surgery (p=0.004). CONCLUSIONS: A method for selecting surgeons for participation in the ACAS trial was successful in providing low perioperative morbidity and mortality rates. This materially influenced the outcome of the study in favor of CEA.

Arteriosclerosis↗