Biomedical subjects

M A Craig

Publications and source records attributed to M A Craig.

6 recordsLinked to original sources

PubMed2001

The effect of femoral prosthesis design on cement strain in cemented total hip arthroplasty.

Finite element studies show that the highest cement stresses are located at the most proximal and distal ends of the prosthesis. In vitro biomechanical and histologic analyses of autopsy-retrieved cemented femoral components show these areas to be associated with cement-prosthesis debonding. In this study, cement strains were measured in 2 geometrically different femoral stems in paired cadaver femora: A straight, collared, moderately tapered stem (Centralign) was compared with an anatomically curved, collarless, dramatically tapered stem (Scientific Hip Prosthesis [SHP]). Results showed that the maximum strain and the overall strain profile differed between the 2 stems. The Centralign had peak strains located at the most proximal gauge positions, whereas the peak strains of the SHP were located around the middle of the femoral stem. Minimization of cement strain, especially at the crucial proximal and distal areas of the stem, by altering component design may be able to reduce cement-prosthesis debonding and improve clinical results.

Arthroplasty, Replacement, Hip↗

PubMed1999

A biomechanical analysis of internal fixation of complex tibial plateau fractures.

OBJECTIVE: To compare the mechanical stability of fixation of an unstable bicondylar tibial plateau fracture with several different fixation techniques in a cadaveric model. DESIGN: Randomized laboratory investigation using a simulated bicondylar tibial plateau fracture with metaphyseal-diaphyseal dissociation. SETTING: Complex tibial plateau fractures were instrumented and tested under ramp and cyclic loading conditions on a servohydraulic materials testing machine. INTERVENTION: Each tibia was instrumented sequentially with a lateral buttress plate, a lateral and a medial buttress plate, and a lateral buttress and an anteromedial antiglide plate for ramp load testing. For cyclic testing, one of the three constructs was used on each specimen. MAIN OUTCOME MEASUREMENTS: Vertical subsidence of the medial tibial plateau was measured in both ramp and cyclic loading in order to evaluate the three internal fixation techniques. RESULTS: No significant difference was measurable between the dual buttress construct and the lateral buttress/anteromedial antiglide construct. However, the lateral buttress plate alone provided significantly less stability. CONCLUSIONS: A lateral buttress plate with an anteromedial antiglide plate may provide equally effective fixation as compared with the dual buttress plating technique in complex tibial plateau fractures. This less invasive technique may also be associated with fewer complications due to the lack of soft tissue stripping that is required for its application.

Aged↗

PubMed1997

HLA-DQA1 genotyping by bi-directional sequencing of PCR-amplified DNA spanning exon 2.

We describe a simple, reliable technique for HLA-DQA1 genotyping based on direct DNA sequencing of PCR amplified fragments from genomic DNA. The alleles of DQA1 can be divided into two subsets, with one subset demonstrating a 3 base deletion in exon 2 relative to the other. Typing heterozygous individuals who possess one allele from each sub-group can be difficult using a direct sequencing approach, since the two overlapping DNA sequences move out of phase by 3 nucleotides once the point of deletion is reached. The complete sequence is obtained by performing two separate sequencing reactions with fluorescent dye primers, coming from either end of the template. This allows all heterozygous positions in exon 2 to be unambiguously assigned.

Base Sequence↗

PubMed1996

Implementing a continuous renal replacement therapies program.

Initiating and maintaining a continuous renal replacement therapy (CRRT) program presented more challenges than first anticipated; however, problems remained within the health care team's ability to solve. Here a multidisciplinary group reflects on what was done, should have been done, and remains to be done to offer effective CRRT at this university medical center. All participating members have come to realize that communication and collaboration are necessary to accomplish implementation of a complex program such as CRRT.

Academic Medical Centers↗

PubMed1990

Changes in mallard (Anas platyrhynchos) serum chemistry due to age, sex, and reproductive condition.

Selected serum constituents were analyzed from 50 adult mallards (Anas platyrhynchos) of both sexes during several stages of reproduction: pre-egg laying, egg laying, incubating, molting, and postreproductive. Similar assays were conducted on sera from ducklings aged 5 to 58 days. Values for total protein (TPR), albumin (ALB), glucose (GLU), gamma-glutamyl transferase (GGT), calcium (CA), phosphorus (PHOS) and magnesium (MG) differed by sex. When all data were combined and analyzed for sex-related differences within each reproductive condition separately, all assays except lactate dehydrogenase (LD-L), cholinesterase (CHE), alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine (CRN) and direct bilirubin (BIDI) differed between sexes during one or more reproductive periods. Each assay showed differences among the various reproductive conditions regardless of gender. The pattern of change differed between sexes. All assays except ALB, GLU, CA and MG showed age-related changes. Lipemia in the sample interfered with all chemistries except TPR, LD-L and CA. Results indicate that when using clinical chemistry as a diagnostic tool in the mallard, age and reproductive condition should be determined in order to compare the data to appropriate control values.

Age Factors↗

PubMedDate not supplied

Transient diplegia in children who fail to thrive.

We describe a group of eight children seen over a 4-year period. After a few months of apparently normal health and development, the children developed feeding difficulty, failed to thrive and had mild diplegia. No other underlying pathology was demonstrated. After a period of careful attention to feeding in the stimulating environment of a child development centre, the feeding difficulty, developmental delay and diplegia all disappeared, but, by school age, the children showed learning or behavioural difficulty. It is suggested that these children suffered a subtle neurological insult during the intra-uterine period and that this predisposed them to the neurological difficulty and failure to thrive. It is important to distinguish this small group of children from those in whom non-organic failure to thrive is found and parental neglect is suspected.

Eating↗