Biomedical subjects

C P Desilets

Publications and source records attributed to C P Desilets.

3 recordsLinked to original sources

PubMed1991

Semipermeable-surface reversed-phase media for high-performance liquid chromatography.

Polyoxyethylene was both adsorbed hydrophobically (through the use of non-ionic surfactants) and covalently bonded to reversed-phase high-performance liquid chromatographic packings, thereby establishing a semipermeable hydrophilic layer over the alkylsilane surface. This layer restricts proteins from adsorbing to the alkylsilane phase while permitting penetration and chromatographic separation of small molecules. Biological fluids containing low-molecular-weight analytes may be injected directly, without sample pretreatment or the use of micellar eluents. In the case of adsorbed coatings, surfactant loading was determined primarily by the surface area (over the reversed phase) occupied by the polyoxyethylene head group. Semipermeability of the hydrophilic layer was demonstrated by observing changes in retention of both small molecules and proteins with increasing eluent ionic strength. Coated column stability was evaluated with regard to cumulative eluent volume and repeated serum injections.

Adsorption↗

PubMed1990

Development of synthetic bone-repair materials for craniofacial reconstruction.

In an effort to minimize problems associated with use of bone grafts and bank bone for craniofacial reconstruction, synthetic biodegradable alternatives are under development at the U.S. Army Institute of Dental Research. The focus is on composite materials in which either d,l-polylactide co-glycolide or porous tricalcium phosphate function as degradable delivery systems for bone-inductive proteins. Availability of synthetic bone-repair materials would eliminate the need for invasive graft-harvesting procedures, the dangers of pathogen transmission from, and immunogenic reaction to bank bone. In addition, synthetics should be more easily sculpted to restore facial contours. Elimination of the disadvantages of natural bone grafts would result in improved reconstructive care for victims of trauma, disease, and congenital deformity. Military surgeons can especially appreciate the potential of a convenient synthetic bone replacement for use in mass casualty situations where access to, and storage facilities for natural bone will be extremely limited. This review updates current treatments and requirements for synthetic bone-repair materials and describes several experimental materials under evaluation at the U.S. Army Institute of Dental Research.

Biocompatible Materials↗

PubMed1987

Molecular weights of technetium hydroxyethylidene diphosphonate complexes.

The results of recycle size-exclusion and anion-exchange chromatography are combined to determine molecular weights and radii of gyration for selected components of a carrier-added technetium hydroxyethylidene diphosphonate radiopharmaceutical bone-imaging preparation. Samples evaluated by size-exclusion are selected from fractions collected as the preparation elutes from the anion-exchange column. Polyethylene glycol and polyphosphate molecular weight standards are used, in conjunction with the universal calibration method, to determine Mark-Houwink constants and to estimate molecular weights for the complexes. The results of this study support a spherical shape model for the collection of technetium complexes. Given the combined knowledge of molecular weights, charges, technetium concentration dependencies, and mass spectral data, several formula assignments are proposed, including TcO(OH)L-1, Tc2O(OH)6L-3, Tc2O(OH)2L3(-6), Tc3O2(OH)3L2(-5), Tc3O2(OH)3L3(-7), Tc2O2(OH)4(HL)3(-7) and Tc2O2(OH)4(H2L)4(-8).

Chemical Phenomena↗