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Biomedical subjects

J D Kelly

Publications and source records attributed to J D Kelly.

171 records · Page 10Linked to original sources
PubMedDate not supplied

Mechanism of uptake of technetium-tetrofosmin. I: Uptake into isolated adult rat ventricular myocytes and subcellular localization.

BACKGROUND: 99mTc-labeled tetrofosmin is a new myocardial imaging agent that gives stable heart uptake. However, little is known about the mechanism of uptake in heart tissue. METHODS AND RESULTS: Uptake of 99mTc-labeled tetrofosmin has been examined in isolated adult rat ventricular myocytes. The time course of uptake, efflux rate, and the effect of metabolic and cation channel inhibitors have been assessed. The subcellular localization of radioactivity in ex vivo rat heart tissue was examined by differential centrifugation of ventricular homogenate. Uptake into rat myocytes was found to be rapid and plateaued at approximately 1.5 pmol/10(6) cells/nmol extracellular Tc-labeled tetrofosmin after 60 minutes of incubation. Uptake was temperature dependent but independent of extracellular Tc-labeled tetrofosmin concentration. Uptake at 30 minutes was inhibited by the metabolic inhibitors iodoacetic acid acid and 2,4-dinitrophenol protein but was not affected by cation channel inhibitors. Cells previously incubated with 99mTc-labeled tetrofosmin and then placed into fresh medium were found to have a slow efflux of activity; after 1 hour, 65% of activity was still cell associated. The localization of radioactivity in subcellular fractions indicated that the majority of activity was recovered with the cytosol. However, examination of the distribution of two mitochondrial enzymes indicated that this may have been artifactual. Use of carbonyl cyanide m-chlorophenyl-hydrazone or oligomycin to perturb mitochondrial membrane potential decreased or increased recovery in the mitochondrial fraction, respectively. CONCLUSIONS: 99mTc-labeled tetrofosmin uptake by myocytes is by a metabolism-dependent process that does not involve cation channel transport. The most likely mechanism for this is by potential driven diffusion of the lipophilic cation across the sarcolemmal and mitochondrial membranes.

Animals↗
PubMedDate not supplied

Association of burners with cervical canal and foraminal stenosis.

The purpose of this study was to determine whether the burner phenomenon is associated with cervical canal and foraminal stenosis in a scholastic population. Lateral cervical radiographs were reviewed for 64 athletes, 15 to 18 years of age, who had sustained at least one burner. Controls consisted of age-matched athletes who had sustained head or neck trauma without evidence of the burner phenomenon (N = 32). Pavlov ratios were calculated for levels C-3 through C-6; both mean minimum and mean average ratios were determined. Available oblique radiographs from both the study (N = 31) and control (N = 15) groups were then used to calculate the foramen/vertebral body ratio--a measure of relative foraminal height. Significant differences were found between the burner and control groups for the mean minimum and mean average Pavlov ratios and foramen/vertebral body ratios. Scholastic athletes sustaining the burner phenomenon have an increased risk of cervical canal and foraminal stenosis as measured by the Pavlov and foramen/vertebral body ratios, respectively. The foramen/vertebral body ratio is an easily reproducible and reliable means of assessing foraminal dimensions from oblique radiographs and controls for x-ray magnification and rotation. Foraminal stenosis assessment may prove useful in predicting burner risk, especially in athletes with extension-compression injuries.

Adolescent↗
PubMedDate not supplied

Delayed repair of a ruptured pectoralis major muscle. A case report.

Repair of a pectoralis major muscle rupture at the tendinous insertion into the humerus was successfully performed 13 years after the initial injury. Repair was possible only because the ruptured sternal portion of the muscle was scarred to the intact clavicular portion and therefore had not retracted. The attachment of the avulsed sternal head to the intact clavicular head enabled successful restoration of strength and function, as well as normal contour and appearance of the pectoralis major muscle complex.

Adult↗
PubMedDate not supplied

Anatomy and kinematics of the lateral collateral ligament of the knee.

The anatomy and kinematics of the lateral collateral ligament were studied in 10 unembalmed limbs and 20 isolated femurs and fibulas. The ligament's average overall length was 66 mm (range, 59 to 74) and the average greatest dimension of its thin middle portion was the anteroposterior dimension of 3.4 mm (range, 3 to 4). The center of the femoral attachment site was 3.7 mm posterior to the ridge of the lateral epicondyle, not at it apex. A potential radiographic technique for operatively locating the femoral attachment site to within 3 mm is described. During knee flexion in neutral rotation the distance between the femoral and fibular attachment sites of the lateral collateral ligament decreased to 88% of its value in full extension. With 6.5 N x m of applied external rotation force, beyond 30 degrees of flexion the attachment sites rapidly approximated. With the same internal rotation force, beyond 15 degrees of flexion the attachment sites separated. From 60 degrees to 105 degrees they were greater than 100% of the value in full extension, suggesting significant distraction between the attachment sites. These changes correlated well with the ligament's change from an 11 degrees posterior slope in extension to a 19 degrees anterior slope in flexion with no applied rotation.

Aged↗
PubMedDate not supplied

Acute compartment syndrome of the lower extremity secondary to noncontact injury.

We retrospectively reviewed the cases of three patients with injuries similar to the mechanism of an ankle sprain which resulted in compartment syndrome of the lower extremity. All three patients presented with sharp, proximal, anterolateral pain in the leg after an indirect, twisting injury. None of the injuries involved direct contact. Two of the three athletes initially presented to local hospitals, where the injury was misdiagnosed as an ankle sprain. The mechanism appears to be a muscle strain or tear with resultant hemorrhage in the compartment. All three patients returned to high-level athletics after prolonged recovery periods.

Adolescent↗