Search PubMed⌕ Search

Biomedical subjects

F C Smith

Publications and source records attributed to F C Smith.

At least 55 records · Page 3Linked to original sources
PubMed1993

Reperfusion plasma contains a neutrophil activator.

Aortic aneurysm repair produces inflammatory mediators, neutrophil activation, and remote organ injury. Reperfusion plasma from these patients produces microvascular injury in an ex vivo chemotactic model. This study investigates the mechanism of this injury. Vena caval blood was obtained before and 15 minutes after aortic clamp removal (n = 16) or at laparotomy (n = 10). Plasma or saline solution was introduced into unit dose chambers fixed atop dermabrasions on the back of depilated anesthetized rabbits. Animals were treated with intravenous saline solution (n = 4); made neutropenic with nitrogen mustard (n = 4); pretreated with the xanthine oxidase inhibitor allopurinol (n = 4); or cotreated intravenously with the free radical scavengers superoxide dismutase (SOD) and catalase (n = 4). Three hours later neutrophil counts (polymorphonuclear cells [PMN]/mm3) and activity (free radical production by flow cytometry), protein leakage, and inflammatory mediators (thromboxane [TX] and leukotriene B4 [LTB4]) were measured. In contrast to control plasma in untreated rabbits, reperfusion plasma produced TX and LTB4 generation (1090 +/- 105 and 794 +/- 91 pg/ml, respectively, p < 0.01), PMN accumulation (1636 +/- 210/mm3, p < 0.01) and activation (276 +/- 31 mean fluorescent units), and microvascular permeability (554 +/- 90 micrograms/ml, p < 0.01). Neutropenia (3 +/- 1 PMN/mm3) and cotreatment with SOD and catalase abolished these responses, whereas pretreatment with allopurinol did not. Human reperfusion plasma contains a soluble factor that stimulates free radical generation by rabbit neutrophils to produce a microvascular injury characterized by de novo TX production, neutrophil accumulation and activation, and increased microvascular permeability to protein.

Allopurinol↗
PubMed1993

Adjuvant prostanoid treatment during femorodistal reconstruction.

A prospective randomized placebo-controlled trial was conducted to determine the effects of the stable prostacyclin analogue iloprost on early graft patency and hemodynamic parameters during femorodistal reconstruction for critical leg ischemia. Peripheral resistance and graft blood flow were measured using an operative Doppler flowmeter and graft pressure transducer. Postoperative graft surveillance was continued at 1-month and then at 3-month intervals by duplex Doppler ultrasonography, measurement of ankle-brachial pressure indices, and intravenous digital subtraction angiography when indicated. In patients receiving 3000 ng of iloprost (n = 45) infused into the graft on completion there was an immediate mean decrease in peripheral resistance of 44% that persisted to skin closure in comparison with controls (n = 38) in whom no such decrease in resistance occurred (p < 0.001, Wilcoxon test). During the same period, mean graft blood flow increased in iloprost-treated patients by 74.5% compared with controls in whom there was a 6% increase in flow (p < 0.001). Primary cumulative patencies at 1 month were significantly higher in iloprost-treated grafts, 98% compared to 83% for controls (p < 0.05, log-rank test). Cumulative primary patencies at 1 year and secondary patencies at 1 month and 1 year were also greater in the iloprost-treated group (67%, 98%, and 87.6%, respectively) compared to controls (65%, 86%, and 79.3%, respectively), but these did not achieve statistical significance. A single bolus infusion of iloprost has prolonged beneficial effects on graft blood flow and peripheral resistance during femorodistal reconstruction. This is reflected by improved early primary graft patencies.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Modified technique for balloon valvuloplasty of critical pulmonary stenosis in the newborn.

OBJECTIVES: We report our experience in eight consecutive neonates who underwent attempted balloon dilation as an initial therapy for critical valvular pulmonary stenosis, and we review in detail technical modifications that improved the success rate. BACKGROUND: Balloon dilation of the pulmonary valve has become the treatment of choice for valvular pulmonary stenosis in children and adults. There are few reports of its effectiveness in critical pulmonary stenosis in the newborn. In this setting, application of the technique of balloon dilation has been limited by the ability to advance the necessary guide wires and catheters across the stenotic, often near-atretic, pulmonary valve. METHODS: The pulmonary valve was crossed in all patients. When this could not be accomplished with an end-hole catheter, a soft guide wire was advanced directly across the pulmonary valve through the end-hole catheter positioned in the right ventricular outflow tract below the valve. Initial predilation was achieved in all patients by using a coronary dilation catheter in an effort to facilitate introduction of the definitive balloon dilation catheter. Definitive dilation with a balloon diameter of > or = 110% of the diameter of the pulmonary valve annulus was possible in six patients. RESULTS: Right ventricular pressure declined from a mean value of 108 +/- 32 mm Hg to a mean value of 49 +/- 11 mm Hg after balloon dilation, with no change in heart rate or aortic pressure in these six patients after definitive balloon dilation. CONCLUSIONS: The results of this small series suggest that critical valvular pulmonary stenosis in the newborn can be successfully treated by transluminal balloon valvuloplasty.

Cardiac Catheterization↗
PubMed1992

Effect of prostacyclin analogue iloprost on haemodynamic parameters during femoro-crural reconstruction.

A randomised placebo-controlled trial was conducted to investigate the effects of iloprost, a stable prostacyclin analogue, on peripheral resistance, graft blood flow and mean systemic arterial blood pressure (MABP) during femoro-crural arterial bypass. 3000ng of iloprost, infused into the graft, produced an immediate drop in peripheral resistance by a mean (range) of 40% (4-80%) (P less than 0.01, Wilcoxon). Decreased peripheral resistance persisted to 20 minutes. Graft flow during the same period increased by 52% (-7 to 294%) (P less than 0.01). A transient maximal drop in mean MABP of 22% from 83-65 mmHg occurred 5 minutes post iloprost infusion but caused no detrimental effects and recovered to baseline values by 10 mins. Iloprost produces an immediate decrease in peripheral resistance associated with a prolonged increase in graft blood flow. This may reduce graft failure in the early postoperative period.

Aged↗
PubMed1992

Iloprost reduces peripheral resistance during femoro-distal reconstruction.

A randomised placebo-controlled trial was conducted to investigate the effect of iloprost, a stable prostacyclin mimetic, on peripheral resistance during femoro-distal bypass. Patients undergoing femoro-distal long saphenous vein bypass for critical ischaemia received 3000 ng of iloprost or placebo infused into the graft via an unligated side branch over 2 min. Graft blood flow and peripheral resistance were measured for 20 min, using an operative Doppler flowmeter (OpDop 130, SciMed, U.K.) and a pressure transducer to record graft pressure. Postoperatively, graft blood flow was assessed by daily duplex ultrasound for 7 days. Iloprost produced an immediate drop in peripheral resistance in all cases (n = 18) by a mean (range) of 40% (4-80%) compared with controls (n = 15) in whom there was a 5.3% (-8 to +36%) increase in resistance (p less than 0.01, Wilcoxon test). Decreased peripheral resistance in iloprost-treated patients persisted to 20 min. The largest decreases in peripheral resistance occurred in patients with the highest initial resistances (r = 0.56, p less than 0.02). Graft flow during the same period increased by 52% (-7 to 294%) compared with controls in whom there was a 6% (-17 to 26%) increase in flow, (p less than 0.01). Flow remained elevated by 53% over baseline values at 1 week post-infusion in the iloprost-treated group but this did not achieve statistical significance compared to controls in whom flow also increased by 13%. Iloprost produces an immediate decrease in peripheral resistance associated with a prolonged increase in graft blood flow. This may reduce graft failure in the early postoperative period.

Aged↗
PubMed1992

Pharmacological manipulation of peripheral resistance during distal vascular reconstruction.

A randomised placebo-controlled trial was conducted to investigate the effects of iloprost, a stable prostacyclin analogue, on peripheral resistance, during femoro-crural arterial bypass. 3000 ng of iloprost, infused into the graft, produced an immediate drop in peripheral resistance by a mean (range) of 43% (4-80%; p less than 0.01, Wilcoxon). Decreased peripheral resistance persisted to 20 minutes. Graft flow during the same period increased by 59.8% (-7 to 294%; p less than 0.01) and this increase persisted after the operation. Iloprost produces an immediate decrease in peripheral resistance associated with a prolonged increase in graft blood flow. This may reduce graft failure in the early postoperative period.

Aged↗
PubMed1991

The changing pattern of infective endocarditis in childhood.

Forty-eight cases of infective endocarditis (IE) that occurred in 42 patients with congenital heart disease were reviewed from 1970 through 1990 and were compared with a 20-year review of 108 cases diagnosed between 1953 and 1972. The review demonstrates that the natural history of IE in children has changed over the last 2 decades, with half of the cases occurring after surgery for congenital heart disease. In the postoperative group, 46% of patients had undergone valve replacement and 7 of these (29%) had a right ventricular to pulmonary artery valved conduit as the site for IE, suggesting significant additional risk in this setting. Among patients with nonsurgically treated congenital heart disease and IE, mitral valve prolapse has emerged as an important underlying heart lesion occurring in 29% of patients. The bacterial spectrum has shifted, with a significant increase in the incidence of uncommon causative organisms. Mortality has continued to decline with survivorship of 90% in this series.

Adolescent↗
PubMed1990

Effectiveness of intermittent pneumatic leg compression for preventing deep vein thrombosis after total hip replacement.

A randomized trial was performed in consecutive patients undergoing total hip replacement to evaluate the effectiveness of sequential intermittent calf and thigh compression for preventing venous thrombosis compared with a control group given no prophylaxis. Both groups underwent case finding for deep vein thrombosis using combined fibrinogen I 125 leg scanning, impedance plethysmography, and venography. Deep vein thrombosis by venography was present in 77 (49%) of 158 control patients compared with 36 (24%) of 152 patients given intermittent compression. Proximal vein thrombosis was present in 42 controls (27%) compared with 22 patients (14%) given intermittent compression. Combined impedance plethysmography and leg scanning was insensitive in this patient group (sensitivity, 46%); venography was required to detect more than half the patients with venous thrombosis. Sequential intermittent leg compression clinically and statistically significantly reduced the frequency of both proximal vein and calf vein thrombosis. Case finding resulted in early detection and treatment of patients with venous thrombosis.

Female↗
PubMed1987

Rubella--a case for immunising male adolescents.

An outbreak of rubella at a training institution for predominantly adolescent males is described. The cost and inconvenience of the outbreak furnish evidence that immunisation in its own right is worth while, and should not be seen only as a means of protecting susceptible females of child-bearing age.

Adolescent↗
PubMed1986

[The influence of air pollution on health in the Sasolburg area].

Excessive air pollution by industries in the Sasolburg area is suspected of affecting the residents' health in general and the respiratory system in particular. In the present investigation children from primary schools at Sasolburg were compared with those from the neighbouring rural towns of Parys, Heilbron and Frankfort, all with negligible air pollution levels. Although no important differences in the incidence of respiratory illness were evident from the questionnaire administered, there was a significant difference in the forced expiratory volume in 1 second (FEV1) of boys in the two groups. In addition there was an observed trend for all lung functions to be slightly worse in the study area. This trend seemed to be unaffected by the smoking habits of families but the social class from which the children originated might have been a contributory factor.

Air Pollution↗