Biomedical subjects

D G McBride

Publications and source records attributed to D G McBride.

3 recordsLinked to original sources

PubMed2001

Bootstrap methods for sex determination from the os coxae using the ID3 algorithm.

This study presents a method for identifying small subsets of morphological attributes of the skeletal pelvis that have consistently high reliability in assigning the sex of unknown individuals. An inductive computer algorithm (ID3) was applied to a bootstrapped training set/test set design in which the model was developed from 70% of the sample and tested on the remaining 30%. Relative accuracy of sex classification was evaluated for seven subsets of 31 morphological features of the adult os coxae. Using 115 ossa coxarum selected from the Terry Collection, a selected suite of the three most consistently diagnostic attributes averaged 93.1% correct classification of individuals by sex over ten trials. Attribute suites developed collaboratively with three well known skeletal experts averaged 87.8, 91.3, and 89.6% correct. The full set of 31 attributes averaged 90.0% accuracy. We demonstrate a small set of three criteria, selected and ordered by ID3, that is more accurate than other combinations, and suggest that ID3 is a useful approach for developing identification systems.

Algorithms↗

PubMed1997

Failure strengths of suture versus biodegradable arrow for meniscal repair: an in vitro study.

Advances in our understanding of meniscal function and consequences of menisectomy have spawned meniscal repair techniques that yield success rates approaching 90% in properly selected patients. Biodegradable implants have been fashioned for meniscal fixation to simplify the technique and minimize neurovascular complications. We performed the current study to determine the in vitro biomechanical behavior of the BIOFIX Meniscal Arrow, a polylactic acid tack developed for meniscal repair. Eight pairs of menisci were harvested from cadaveric knees kept frozen before testing. Peripheral vertical tears were created in the posterior horn of all menisci, and each was subsequently repaired using a vertical loop suture of 2-0 Ethibond and a Meniscal arrow. Ultimate load to failure of each method was determined on a Hounsfield H25KM Universal Testing machine. The mean failure load for the suture group was 58.3 N compared with the Arrow group mean of 29.6 N (P < .001). All sutures failed by rupture at the knot but did not pull through the meniscus. All but one of the arrows failed by pulling out of the meniscus. The Arrows also permitted gapping at the repair site at considerably lesser loads than the sutures subject to strain. The concept of a biodegradable tack is appealing. Vertical loop sutures should be the standard by which their biomechanical performance is judged. We suggest modifications to the Arrow design that could enhance the fixation strength of this implant.

Aged↗

PubMedDate not supplied

Cardiopulmonary and sinoaortic baroreceptors and volume expansion in the monkey.

Experiments were performed to determine the effect of combined cardiopulmonary and and sinoaortic baroreceptor denervation on the renal responses of the anesthetized nonhuman primate to acute intravascular volume expansion. Adult male Macaca fascicularis monkeys underwent chronic bilateral thoracic sympathectomy (middle cervical ganglion--T6) or sham surgery performed in two stages. After a 1-3 week recovery period, each animal was anesthetized with sodium pentobarbital and subjected to cervical vagotomy--sinoaortic denervation or further sham denervation. Estimated blood volume was then acutely expanded 20% with 6% dextran in isotonic saline. Control renal excretory function did not differ between the two groups, and both groups had similar increases in urine flow, sodium excretion, osmolar clearance, free water clearance and renal plasma flow after volume expansion. The patterns of the responses showed some group differences in that the increases in renal excretion after volume-loading had an earlier onset in the denervated animals. These results demonstrate that combined ablation of thoracic sympathetic, vagal and sinoaortic neural pathways does not compromise the ability of the nonhuman primate to increase salt and water excretion when blood volume is acutely expanded. Therefore, these neural mechanisms are not necessary for eliciting the renal responses to this hypervolemic stimulus in this species during the anesthetized state.

Animals↗