PubMed Health⌕ Search

Biomedical subjects

C R Saunders

Publications and source records attributed to C R Saunders.

At least 19 recordsLinked to original sources
PubMed2003

Off pump concomitant coronary revascularization and carotid endarterectomy.

AIM: Off pump coronary revascularization has emerged as a viable option in the treatment of coexisting clinically significant carotid and coronary artery disease. To this end, we report our recent experience with combined carotid endarterectomy (CEA) and off pump coronary artery bypass (OPCAB). METHODS: Our prospectively updated database was queried to identify all patients who underwent combined OPCAB/CEA between January 1, 1999 and December 31, 2002. A total of 38 patients were identified. They were subsequently compared to a contemporaneous cohort of isolated off-pump patients divided into those with and without cerebrovascular disease (CVD). RESULTS: Mean age of the study population was 71+/-7.0 years, 23 patients (58%) had significant left main disease, 5 (13%) suffered a previous stroke and 5 (13%) had ejection fractions <or=30%. The study group had 1 postoperative myocardial infarction and no postoperative cerebrovascular accidents (CVA). There was 1 in-hospital death (3%) however, there were no significant differences noted in mortality between the study groups. CONCLUSION: The optimal management of the multifocal atherosclerotic patient remains controversial and this dilemma is further clouded by the recent introduction of OPCAB, and more recently, carotid stenting. Our results suggest that combined OPCAB/CEA is safe and may reduce the risk of postoperative stroke. An economic benefit may also be inferred from shorter hospitalization as well as eliminating the need for another procedure. Randomization and long term follow-up are now required to verify these encouraging early findings.

Aged↗
PubMed2001

Behavioral effects induced by acute exposure to benzo(a)pyrene in F-344 rats.

Polycyclic aromatic hydrocarbons (PAHs) are highly persistent environmental pollutants which pose potential adverse effects on human health. Benzo(a)-pyrene (B(a)P) is the prototypical representative of these widely dispersed lipophylic contaminants. (B(a)P) exposure in experimental animals results in an array of tissue- and organ-specific responses including carcinogenicity, teratogenicity, reproductive and immunotoxicity. However, no previous studies have examined the potential neurobehavioral toxicity of B(a)P in vivo. The present study was conducted to investigate the behavioral effects induced by single oral doses of (B(a)P) in 8-week-old male and female F-344 rats. Rats were exposed to 0, 12.5, 25, 50, 100 and 200 mg/kg of B(a)P by oral gavage. Motor activity measurements and the functional observational battery (FOB) were used to assess behavioral changes induced by B(a)P at 2, 4, 6, 8, 10, 12, 24, 48, 72 and 96 h post treatment. Statistical analyses revealed significant (p <0.001) dose, sex and time interactions. (B(a)P) doses ranging from 25 to 200 mg/kg produced a significant suppression (up to 60%) in four motor activity parameters: horizontal activity, total distance, stereotype and vertical activity in both sexes within 2 and 4h of dosing. B(a)P treated male and female animals also showed significant (p <0.001) changes in neuromuscular, autonomic, sensorimotor and physiological functions within 2 and 4h post B(a)P administration except in the 12.5 mg/kg treatment group. The 12.5 mg/kg dose did not produce significant (p > 0.05) behavioral toxicity in either males or females. All treated animals (25-200 mg/kg) recovered from the toxic effects of B(a)P by 72 h. Significant (p < 0.05) gender differences were noted in FOB test measures with males displaying greater sensitivity to B(a)P. These data suggest that motor activity and FOB measurements can be used as indices to detect B(a)P neurotoxicity.

Journal Article↗
PubMed2001

Combined off-pump myocardial revascularization and carotid endarterectomy: early experience.

BACKGROUND: Controversy remains regarding the optimal surgical management of patients with coexisting significant carotid and coronary artery disease. The debate has deepened by the evolution of new approaches for the treatment of both coronary and carotid disease. We report our early experience with combined off-pump coronary artery bypass (OPCAB) and carotid endarterectomy (CEA) for the treatment of patients with coexisting coronary and carotid disease. METHODS: Our computer database was examined to obtain patients and their demographics and clinical profiles. Operative reports were reviewed. Telephone interviews were conducted to assess follow-up status. RESULTS: Thirteen patients underwent combined OPCAB and CEA. Average age was 71 years. The CEA was performed with intraluminal shunting and patch reconstruction. On average, 3.6 bypass grafts were performed. There were no gross neurologic complications or myocardial infarctions. Excluding an outlier, mean length of hospital stay was 8.2 days. All patients were well on follow-up (2 weeks to 16 months). CONCLUSIONS: A combined OPCAB and CEA strategy appears safe and effective. Further follow-up and experience is warranted before conclusions regarding potential benefits of this approach for staged or conventional OPCAB/CEA procedures can be made.

Aged↗
PubMed2000

Influence of ceramic and stainless steel brackets on the notching of archwires during clinical treatment.

The surface topography of 100 clinically used archwires of stainless steel, beta-, or nickel-titanium were investigated that had contacted either ceramic or stainless steel brackets. One group consisted of two sets: 60 wires with no treatment records accessed to bias analyses, and 40 wires for which extensive clinical records were available, half of which were used with ceramic or stainless steel brackets. A control group consisted of two sets: 30 unused wires comprised of five round and rectangular wires of each alloy, and four wires that were ligated and immediately removed from patients' mouths. After ultrasonic cleaning, each wire was inspected under an optical and/or a scanning electron microscope. Notches were categorized with regard to frequency, patterns, and severity, and mapped as a function of wire aspect (lingual, facial, and occlusal/gingival) and anatomical regions (molar, premolar, canine, and incisor). From these data the average severity of notch patterns and a notching index were derived. Although no recognizable defect patterns were observed in the control group, seven basic patterns were recognized for each wire cross-sectional shape in the clinically used wires. These wires appeared most damaged on their lingual aspect and least damaged on their facial aspect. With regard to anatomical regions, notching was prevalent in the anterior regions and sparse in the molar regions. The notch activity and the severity were nearly three times greater from ceramic brackets than from stainless steel brackets. Over one-third of all notches documented in ceramic bracket cases had severity numbers of 3 and penetrated at least one-quarter of each wire's dimension, However, over two-thirds of all notches documented in stainless steel bracket cases had severity numbers of 1. From these tabulations a theory of notch formation was proposed in which vertical movement from tooth or wire during mastication caused fretting wear, and horizontal movement during orthodontic procedures such as space closure, tipping, or bodily movement caused sliding wear.

Ceramics↗
PubMed1998

Long-term results of the Carpentier-Edwards pericardial aortic valve: a 12-year follow-up.

BACKGROUND: Pericardial valves have excellent hemodynamic function; however, long-term durability is questionable. To determine the function of the Carpentier-Edwards pericardial valve in the aortic position, the results of 310 aortic valve replacements performed between 1982 and 1985 were analyzed. Mean age was 64.2+/-10.8 years (range, 22 to 95 years); 190 (61.3%) were men. Isolated valve replacement was performed in 135 patients (43.5%). There were 18 hospital deaths (5.8%), none of them valve related. METHODS: Follow-up of 292 survivors was 100% complete at a mean of 8.8 years; 2,556 patient-years of follow-up were analyzed. There were 150 late deaths (51.4%). Survival at 5, 10, and 12 years were 83%+/-2%, 47%+/-3%, and 34%+/-3%, respectively. The 12-year actuarial and actual freedom from thromboembolism was 87%+/-2% and 89%+/-2%, respectively. Freedom from hemorrhage was 91%+/-2% and 92%+/-2%; freedom from endocarditis was 93%+/-2% and 95% +/- 1%; and freedom from structural deterioration was 82%+/-4% and 91%+/-2%, respectively. RESULTS: Actuarial freedom from structural deterioration at 12 years was considerably higher for 153 hospital survivors 65 years or older, 93% (5 explants) compared to 76% (19 explants) for patients younger than 65 years, p = 0.03. Of 24 explanted valves for structural deterioration, leaflet calcification resulting in stenosis occurred in 20 (83%) and 4 were wear-related leaflet tears. CONCLUSIONS: We conclude that the Carpentier-Edwards pericardial valve has a low incidence of valve-related complications, that structural deterioration is infrequent and results from leaflet calcification, and that the low incidence of structural deterioration in patients 65 years or older makes this an increasingly appropriate option in this age group.

Actuarial Analysis↗
PubMed1994

Surface topography and frictional characteristics of ceramic brackets.

The surface topography and frictional characteristics of single crystal sapphire and polycrystalline alumina brackets were evaluated in both the dry and the wet state as a function of the four basic wire alloy compositions. On the premise that a particular combination of bracket, wire, and environment must be attained so that the efficiency and reproducibility of tooth movement is improved, a significant reduction in the coefficients of friction was sought. Viscometric measurements were used to show that the characteristics of saliva remained unchanged throughout the investigation. Scanning electron micrographs and laser specular reflection were studied to illustrate the general appearance and quantitative magnitude of roughnesses. Frictional measurements of couples in the dry, the wet, and again in the dry state were evaluated at five different normal loads. The outcomes of the virgin materials show that arch wire alloy, rather than bracket product type or surface roughness, influence the frictional characteristics the most and that titanium wires generally cause higher frictional resistances than either stainless steel or cobalt-chromium wires. Friction tests of specimens that were run multiple times suggest that couples comprised of nickel titanium arch wires against ceramic brackets may actually improve as a result of a break-in period.

Alloys↗
PubMed1983

Hydroxyethyl starch versus albumin in cardiopulmonary bypass prime solutions.

To compare hydroxyethyl starch (HES) with 25% albumin, 20 patients undergoing aortocoronary bypass were randomized into two groups: 10 received 1,000 ml of HES and 10 received 200 ml of 25% albumin in a bloodless priming solution for cardiopulmonary bypass (CPB). Platelet aggregation, antithrombin III, reptilase time, fibrinogen, plasminogen, fluid requirements, and hemodynamics were monitored. Platelet aggregation was abnormal in both groups, being relatively poorer in the albumin group. Both groups exhibited below normal antithrombin III and plasminogen levels, with significantly lower antithrombin III levels noted in the HES group postoperatively (41.9 +/- 11.8% versus 56.6 +/- 9.9%; p = 0.006). Compared with the albumin group, the HES group had slightly, but not significantly, elevated liver function test results, total volume replacement (9,173 +/- 2,046 ml versus 8,522 +/- 1,192 ml; p = 0.057), packed red blood cell usage (227 +/- 284 ml versus 75 +/- 168 ml; p = 0.066), and chest tube drainage (599 +/- 253 ml versus 454 +/- 174 ml; p = 0.144). In the HES group, 5% albumin requirement was greater (386 +/- 466 ml versus 50 +/- 158 ml; p = 0.002) and percent increase of body weight was higher (5.2 +/- 0.8% versus 2.3 +/- 0.6%; p = 0.05) postoperatively. Postoperative weight increase and colloid requirements plus trends toward larger blood loss and blood transfusions indicate possible further evaluation. However, results suggest that HES is a safe additive to priming solutions. Compared with albumin, HES has comparable changes in coagulation variables and slightly less severe derangements in platelet aggregation.

Aged↗
PubMed1978

Myocardial contusion: effect of intra-aortic balloon counterpulsation on cardiac output.

Intra-aortic balloon counterpulsation (IABCP) improves impaired left ventricular (LV) performance associated with myocardial ischemia. We have evaluated the effect of IABCP on cardiac output (CO) after blunt trauma to the heart where LV performance is impaired by myocardial contusion but coronary blood flow is normal. Contusion of 20 to 40% of the LV in 13 dogs decreased CO by 41% +/- 6.4. A 30-minute period of IABCP was followed by 30 minutes without IABCP with three assist periods in each animal unless death occurred. Immediate IABCP after injury in six dogs increased CO 14% +/- 3.8 (p less than 0.01). Treatment was delayed for 30 minutes in seven dogs, and CO further decreased 0.7% +/- 3.2; initiation of IABCP then increased CO 9.2% +/- 6.5 (p less than 0.05). When CO was decreased less than 25% or greater than 50% after injury, IABCP had no effect on CO. In midrange when CO decreased 25 to 50%, IABCP increased CO 12.5% +/- 3.2 (p less than 0.001 initially, 9.3% +/- 1.3 (p less than 0.005) with second assist, and third assist 5.6% +/- 2(NS). It is concluded that IABCP improves LV performance following myocardial contusion, especially when applied early after injury.

Animals↗