PubMed Health⌕ Search

Biomedical subjects

M Shea

Publications and source records attributed to M Shea.

105 records · Page 6Linked to original sources
PubMedDate not supplied

AO incompatibility in a small group of developmentally disabled children.

Prevalence of fetal-maternal AO incompatibility was studied in a group of 150 children having developmental delay in the neuropsychological sphere. In a given population the number of A children having O mothers (AO incompatibility) should equal the number of O children having A mothers (OA compatibility). However, in the study group we observed 26 children in the former and 14 children in the latter category. This difference was statistically significant (p = 0.04). The frequency of AO incompatibility in the developmentally disabled population was higher (17.3%) than that in 437 child-mother pairs of the general population (10.1%). It was not possible to demonstrate association of any specific neurological defect with AO incompatibility, although the children born from AO incompatible pregnancies tended to start walking later than the other children of the study group.

ABO Blood-Group System↗
PubMedDate not supplied

[Biomechanical studies of bisegmental lumbosacral stabilization using the internal fixator or PMMA-simulated fusion].

The implantation of fixation devices increases the primary stability after surgery significantly. Little is known about the comparison of flexibility of instrumented and posterolateral fusions or the lumbosacral distractions spondylodesis (LSDS). The purpose of the study was to compare the flexibility of instrumented and posterolateral fusions or LSDS after simulation with polymethylmethacrylate (PMMA). Dynamic testing from 0-16 Nm in flexion/compression and 0-900 N in compression was performed on 14 lumbosacral spines. The spines were tested intact, after laminectomy, instrumentation with an internal fixateur L5-S1, and simulation of posterolateral fusion L4-S1 or LSDS and thereafter a pseudoarthrosis was simulated. The laminectomy resulted in a significant increase of flexibility and posterior distraction in flexion and compression. The stabilization with an internal fixateur or PMMA simulation for posterolateral fusion or LSDS resulted in a significant decrease of the flexibility. Creation of a unilateral pseudoarthrosis did not effect the flexibility. The instrumented fusion as well as the PMMA simulated bony posterolateral fusion and LSDS resulted in this model in a significant stabilization of the laminectomy. After unilateral fusion the flexibility was not significantly increased.

Aged↗
PubMedDate not supplied

Critically sized osteo-periosteal femoral defects: a dog model.

A 21-mm defect was created in 1 femoral diaphysis each of 15 dogs. Periosteum as well as a cylinder of bone was removed, and the defect was stabilized with a bone plate. Twelve of the defects were filled with an equal volume of autogenous cancellous bone harvested from the ipsilateral ilium. Three defects were left untreated. Cranial to caudal radiographs were taken postoperatively and every 4 weeks for 16 weeks. The radiographs were evaluated for healing using two ordinal scales. At 16 weeks, the dogs were euthanized and the femurs harvested for biomechanical testing and histologic evaluation. Both operated and contralateral not operated femurs were mechanically tested to failure in torsion, and load at failure and stiffness were calculated. All dogs tolerated the procedure well, and were using the operated limb within 1 or 2 days postoperatively. There were no complications noted during the 16 weeks of the study. Unfilled defects did not heal and became atrophic nonunions. The defects filled with autogenous cancellous bone healed in a consistent pattern of consolidation, incorporation, and remodeling, with uniform increases of both ordinal scales used. The femoral cortex opposite the bone plate demonstrated most mature remodeling, evident both radiographically as well as histologically. Unoperated femurs failed at 13.61 +/- 3.88 N-m and grafted femurs failed at 2.96 +/- 1.3 N-m, which was 23% of the measurement of the unoperated femur. Relative stiffness of the unoperated femurs was 5974 +/- 4316 N-m2/radian, and grafted femurs had a relative stiffness of 642 +/- 561 N-m2/radian, which was 10.4% of the measurement of unoperated femur. This model proved to be a critically sized defect, which when left unfilled resulted in an atrophic nonunion, and when filled with cancellous bone resulted in a consistent healing pattern.

Animals↗
PubMedDate not supplied

Rubidium-82 myocardial uptake and extraction after transient ischemia: PET characteristics.

The effects of transient regional ischemia on monovalent cation uptake and extraction by the myocardium were studied in seven open chest dogs. Following a 10-20% stenosis of the left anterior descending coronary artery to prevent reactive hyperemia, the regional myocardial uptake of the monovalent cation 82Rb (ml/min/g X extraction) was measured before, during, and at 10, 30, and 60-80 min after a 10 min total occlusion of the left anterior descending coronary artery using positron emission tomography. Regional myocardial blood flow was also measured at the same time interval using radiolabeled carbonized microspheres. The regional myocardial extraction of 82Rb was calculated as uptake/flow. In normally perfused myocardial regions there was an inverse relationship between 82Rb extraction and blood flow [extraction = -0.56 (In flow) + 0.46, r = 0.93] over a range of flow from 0.3 to 4 ml/min/g. During the prolonged recovery of 82Rb uptake in the transiently ischemic region, flow had returned to normal levels but 82Rb extraction at a given value of flow was significantly decreased at the 30 and 60-80 min times after release of the occlusion compared with normally perfused regions. Thus, prolonged abnormalities in the 82Rb uptake and extraction occur in myocardium recovering from transient ischemia.

Animals↗
PubMedDate not supplied

Pull-out strength of suture anchors for rotator cuff and Bankart lesion repairs.

Surgical reconstructions of anterior-inferior shoulder instabilities and rotator cuff injuries require secure fixation of soft tissue to bone. Sutures are inserted directly through transosseous tunnels in current techniques, which are surgically complex and not always adequate for fixation strength. Using fresh-frozen cadaveric human specimens, our objectives were 1) to compare immediate pull-out strength of two versions of polyacetal suture anchors (wedge and rod) with conventional suture-only attachment techniques in Bankart lesion and rotator cuff repairs, and 2) to compare pull-out strength of the two polyacetal suture anchors with a metallic suture anchor. Our results indicate no significant differences in fixation strength of Bankart lesions or rotator cuff repairs using sutures only, or using wedge or rod polyacetal suture anchors (P = 0.70). Pull-out force did not differ significantly (P = 0.37) between the two polyacetal anchors. Polyacetal anchors exhibited higher pull-out forces than metallic anchors when inserted into metaphyseal regions of the tibia and significantly higher pull-out forces (P < 0.001) when inserted into metaphyseal regions with thicker cortical walls. Our results indicate that both polyacetal suture anchors provide adequate immediate fixation for soft tissue repairs in the human shoulder.

Acetals↗
PubMedDate not supplied

Specimen processing: centralized or decentralized?

Specimen processing for the clinical laboratories of a large pediatric teaching hospital laboratory was centralized in 1991. A highly efficient service area evolved through reengineering and renovations and effected a 20% reduction in operating costs. Work flow analysis identified areas for improvements, renovations created a more efficient use of space, and staffing decreased from 18.4 to 8.5 FTEs without compromising service.

Centralized Hospital Services↗