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P McGinn

Publications and source records attributed to P McGinn.

7 recordsLinked to original sources
PubMed2006

Improved mechanical properties of acrylic bone cement with short titanium fiber reinforcement.

Acrylic bone cements are widely used in total joint arthroplasties to grout the prosthesis to bone. The changes in the tensile properties and fracture toughness of polymethylmethacrylate (PMMA) bone cements obtained by the addition of control and heat treated short titanium fibers are studied. Heat treatment of titanium fibers is conducted to precipitate titania particles on the fiber surface to improve the biocompatibility of the metal. Control and heat treated short titanium fibers (250 micro long and 20 micro diameter) were used as reinforcements at 3 volume %. X-ray diffraction indicated the presence of a rutile form of titania due to the heat treatments. The tensile and fracture properties were improved by the addition of fibers. Bone cements reinforced with titanium fibers heated at 550 degrees C for 1 h followed by 800 degrees C for 30 minutes show the largest increase in fracture toughness along with the smallest changes in elastic modulus and needs to be further investigated.

Benzoyl Peroxide↗
PubMed2006

Improved mechanical properties of acrylic bone cement with short titanium fiber reinforcement.

Acrylic bone cements are widely used in total joint arthroplasties to grout the prosthesis to bone. The changes in the tensile properties and fracture toughness of polymethylmethacrylate (PMMA) bone cements obtained by the addition of control and heat treated short titanium fibers are studied. Heat treatment of titanium fibers is conducted to precipitate titania particles on the fiber surface, which may improve the biocompatibility of the metal. Control (non-heat treated) and heat treated short titanium fibers (250 microm long and 20microm diameter) were used as reinforcements at 3 volume %. X-ray diffraction indicated the presence of a rutile form of titania due to the heat treatments. Results indicate that the tensile and fracture properties of unfilled bone cement were improved by the addition of control and heat-treated fibers. The fracture properties of bone cements reinforced with control titanium fibers were at least 10% higher than those reinforced with heat treated titanium fibers. Therefore, we recommend further studies on the use of non-heat treated titanium fibers to reinforce acrylic bone cement.

Coated Materials, Biocompatible↗
PubMed2000

Missed opportunities.

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Administrative Personnel↗
PubMed1994

Pseudomonas sepsis does not cause more severe cardiovascular dysfunction in patients than non-Pseudomonas sepsis.

To evaluate the clinical relevance of the experimental findings of a more severe cardiac depression in Pseudomonas (P.) than in non-P. sepsis, we retrospectively compared the hemodynamic data in 26 patients with P. sepsis (20 cases, single pathogen; six cases, more positive cultures with P. than with non-P. species), and 102 with non-P. sepsis. As in other studies, the left ventricular stroke work index (LVSWI) was used to assess cardiac performance. The two groups (all numbers are means) had a similar disease and sepsis severity profile (P. vs. non-P: septic shock, 81% vs. 87%; APACHE II scores, 29.1 vs. 29.2; Elebute sepsis scores, 18.1 vs. 18.1; mortality, 58% vs. 62%). Preload (pulmonary capillary wedge pressure 15.0 vs. 16.3 mm Hg) and systemic vascular resistance (588 vs 572 dyn.cm-5.sec) were comparable. Cardiac performance displayed no significant difference (LVSWI, 42.8 vs. 38.3 g.m/m2), a result reproduced in the subgroups with culture-proven bacteremia, with or without preexisting cardiovascular disease or septic shock. Thus, our data suggest that there is no difference in the degree of cardiovascular dysfunction in patients with Pseudomonas compared to non-Pseudomonas sepsis of otherwise equivalent disease severity.

Cardiovascular System↗
PubMed1985

Perturbational actions of barbiturate analogues on erythrocyte and synaptosomal membranes.

The membrane perturbational actions of pentobarbital, methohexital, and phenobarbital were analyzed in terms of their effects on the incorporation of group-specific chemical probes into protein and phospholipid structural components and on the activity of various functionally distinct ATPases in erythrocyte and brain synaptosomal membranes. When compared at concentrations producing similar degrees of antihemolysis in red cells, the three analogues differed most markedly in the nature and degree of the structural and functional alterations induced in membrane proteins, with the most highly lipophilic agent, methohexital, being frequently, although not invariably, the most potent. Comparison of the effects of pentobarbital on characteristics of trinitrobenzenesulfonic acid and 5,5'-dithiobis-(2-nitrobenzoic acid) incorporation into erythrocyte membranes with results previously obtained using other anaesthetics at concentrations producing 50% antihemolysis showed that pentobarbital behaves similarly to neutral general anaesthetics but differently from cationic local anaesthetics. Our findings suggest that the membrane perturbational characteristics of barbiturates may contribute to their diverse and complex actions on excitable tissues.

Adenosine Triphosphatases↗