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Biomedical subjects

David R Shaw

Publications and source records attributed to David R Shaw.

5 recordsLinked to original sources
PubMed2006

Endovascular treatment of visceral aneurysms associated with pancreatitis and a suggested classification with therapeutic implications.

PURPOSE: To describe a 10-year experience of endovascular and percutaneous treatment of aneurysms and pseudoaneurysms complicating pancreatitis, and to analyze this experience and propose a classification based on computed tomography (CT) and angiographic findings that has therapeutic implications. This may reduce the rate of recurrent bleeding after surgery or endovascular treatment. MATERIALS AND METHODS: Twenty-three patients with aneurysms or pseudoaneurysms associated with acute pancreatitis were treated by endovascular or percutaneous methods. All underwent CT and angiography. The early development of a simple classification based on the CT and angiographic findings was used to guide treatment decisions. In accordance with this classification, 19 patients were treated by primary coil embolization and four were treated by primary percutaneous thrombin injection. RESULTS: Among the 19 patients treated by primary coil embolization, there were two early recurrences of the pseudoaneurysm. All four patients treated by percutaneous thrombin injection exhibited late recurrences and were successfully treated by percutaneous thrombin injections. Twenty-one patients (91.3%) were alive at 6 months. CONCLUSIONS: Endovascular and percutaneous treatment of aneurysms and pseudoaneurysms complicating pancreatitis is safe and effective and is associated with good outcomes, but careful follow-up is necessary. The decision of which treatment option is most appropriate can be made in accordance with a classification based on CT and angiographic appearance.

Adult↗
PubMed2002

7: Soft tissue, bone and joint infections.

Soft tissue infections are common and usually respond rapidly to oral antibiotics; if empirical therapy fails then exposure to unusual organisms should be considered. Septic arthritis requires early recognition, identification of the infecting pathogen and urgent joint washout to prevent irreversible cartilage and bone destruction. Prosthetic joint infection is uncommon but has high morbidity; the best outcomes are achieved with removal of the prosthesis and replacement after at least six weeks of antibiotic therapy. Osteomyelitis often complicates diabetic foot infection with ulceration and is rarely cured by antibiotics alone; early surgical intervention achieves the best outcome.

Adolescent↗
PubMedDate not supplied

Using nonequilibrium thin-disc and batch equilibrium techniques to evaluate herbicide sorption.

Nonequilibrium disc-flow techniques may better reproduce dynamic soil-pesticide interactions than traditional batch sorption studies. Batch kinetic and equilibrium experiments and dual-label thin-disc flow experiments were conducted with atrazine (6-chloro-N-ethyl-N'-isopropyl-1,3,5-triazine-2,4-diamine) and imazaquin [2-(4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl)-3-quinolinecarboxylic acid] using a Demopolis silt loam (loamy-skeletal, carbonatic, thermic, shallow Typic Udorthent; 8% clay, 62 g kg(-1) organic matter, 7.6 pH). Batch kinetic studies with both herbicides revealed an almost instantaneous rapid phase and a much slower gradual phase. The rapid phase was complete after 5 min and equilibrium was reached at 24 h. The rapid phase accounted for 74% and 12 to 30% of the total amounts adsorbed for atrazine and imazaquin, respectively. The sorption of both the rapid and 24-h isotherms for each herbicide best fit the Freundlich equation. The rapid and 24-h K(f) values of atrazine were 1.38 and 2.41, respectively, and the N value of both phases was approximately 0.93. For imazaquin, the rapid and 24-h K(f) values were 0.056 and 035, respectively, and the N value for the rapid phase of imazaquin was 0.71, compared with 0.86 for the 24-h isotherm. In the dual-label thin-disc flow experiments, the average partition coefficient for atrazine at the peak soil concentration point was 1.54. This value closely agreed with the observed rapid-phase K(f) value of 1.38. In contrast, the thin-disc flow experiments failed to detect any imazaquin retention. The thin-disc flow method can allow for a greater resolution of rapid sorption kinetics, which is impractical with batch studies. Along with dynamic partitioning data, the thin-disc flow method may provide kinetics data that may better complement environmental models than coefficients generated with batch techniques.

Adsorption↗
PubMedDate not supplied

Incubation time effects on imazaquin desorption as determined by nonequilibrium thin-soil disc flow.

Because organic sorption in soil may never reach equilibrium, a thin-disc flow nonequilibrium method may be helpful in understanding herbicide-soil interactions. This research was conducted to (i) determine the influence of incubation time on imazaquin [2-(4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl)-3-quinolinecarboxylic acid] desorption from soil, (ii) examine the influence of solution flow velocities on desorption, and (iii) elucidate the most appropriate kinetic model to describe imazaquin leaching. Soil at 7.5% moisture w/w was treated with imazaquin and incubated for 24, 72, and 168 h. Treated soil was sealed in an in-line filter apparatus and rinsed with 5.0 mM CaCl2 at 0.33, 0.67, or 1.0 mL min(-1). Effluent was collected as 1.0-mL fractions for a total of 50 mL. Flow was stopped for 24 h. When flow resumed, fractions were collected for an additional 15 mL. After the initial desorption, 79% of the imazaquin incubated for 24 h was leached. Increasing incubation time beyond 24 h reduced imazaquin leaching. After both desorption events, 13% of the initially applied imazaquin remained in the soil incubated for 168 h, compared with 7% with soil incubated for 24 h. Elovich and Freundlich kinetics accounted for 98% of the variance observed in the imazaquin desorption curves. First-order and diffusion kinetics accounted for 91% of the variance. Incubating soil for 72 h before desorption reduced the rate of imazaquin desorption by approximately 12%, compared with the 24-h incubation treatment. Imazaquin desorption was not affected by wash solution flow rate. These data suggest that the kinetics of desorption in prolonged desorption events are limited by transport phenomena (i.e., particle and film diffusion).

Adsorption↗