PubMed Health⌕ Search

Biomedical subjects

S Locke

Publications and source records attributed to S Locke.

11 recordsLinked to original sources
PubMed1992

Proton magnetic resonance imaging and phosphorus-31 magnetic resonance spectroscopy studies of bromobenzene-induced liver damage in the rat.

Respiratory-gated proton magnetic resonance imaging was used to study the response of the rat liver in situ to bromobenzene, a classic hepatotoxicant. A localized region of high proton signal intensity in the perihilar region of the liver was seen 24-48 hr after an intraperitoneal injection of bromobenzene. Localized proton magnetic resonance spectra from within this region indicated that the increased proton signal intensity was not due to accumulation of fat in the liver, but primarily due to a longer T2 for the proton resonance of water. This is consistent with acute edema in this localized region. In vivo 31P magnetic resonance spectroscopy studies of the same rat livers in situ were performed. Spectroscopic conditions were determined whereby localized, quantitative 31P spectra could be obtained. Using these methods, 10 mmol/kg bromobenzene was found after 24 hr to cause a number of statistically significant (p less than 0.05) effects: a decrease in adenosine 5'-triphosphate levels from 4.1 +/- 0.5 to 3.0 +/- 0.5 mM, a decrease in phosphodiester levels from 11.3 +/- 0.9 to 9.3 +/- 0.7 mM and an increase in the phosphomonoesters from 3.0 +/- 0.4 to 5.5 +/- 1.2 mM (mean +/- standard deviation). High resolution in vitro 31P spectra of perchloric acid extracts of these rat livers showed that the increased phosphomonoester resonance was due to a selective 4.3-fold increase in phosphocholine. Thus, our in vivo and in vitro 31P magnetic resonance spectra are consistent with the hypothesis that a phosphatidylcholine-specific phospholipase C (generating phosphocholine and diacylglycerol) is activated during tissue damage. Both the imaging and spectroscopy results obtained with bromobenzene closely resemble CCl4-induced liver changes previously reported, and may reflect a generalized response of the liver to any acutely acting toxic chemical.

Animals↗
PubMed1992

Etiology of low back pain in elite boardsailors.

Seven elite boardsailors reporting nonradiating low back pain without leg pain during sailing volunteered for detailed examination. In these subjects, the onset of pain was limited to those occasions when sailing positions were held for a significant period of time, e.g., close hauled sailing or in light winds. No pain was described at any other time. The determination of possible antecedent factors was based on the results of clinical assessment, radiological evaluation, and computer tomography (CT) scanning. Apart from limited flexibility in some subjects, the clinical examination of these athletes was normal; CT changes in this group were limited to disc protrusions and bulges, and pars interarticularis defects. Despite the small number of subjects in the present report, it appears that the frequency of these problems exceeds that in the normal population. It may be possible to suggest that risk factors such as body position during prolonged sailing, particularly under light wind conditions without a harness, and limited flexibility may be associated with the radiological findings and may be implicated in the presence of low back pain, although further investigations appears warranted.

Adult↗
PubMed1991

Relationship between performance on lumbar dynamometry and Waddell score in a population with low-back pain.

A prospective, blinded cohort study was performed to investigate the relationship between biomechanical variables measured during lumbar dynamometry and several psychological tests and measures of nonorganic pain behavior. Eighty-five men, aged 18-60 years, who had had low-back pain for longer than 5 weeks participated in the study. Nonorganic pain behavior was measured with the Waddell score, and lumbar function was measured with the Isostation B-200 Lumbar Dynamometer. Two brief psychological tests, the Coopersmith Self-Esteem inventory and an analog self-rating of wellness, were also administered. Relationships between biomechanical variables and psychological tests were calculated with the t-test, the Pearson r correlation, analysis of variance, and multiple step-wise logistic regression. Patients who exhibited excessive illness behavior (Waddell Scores 3-5) performed significantly worse (P less than .01) on almost all biomechanical variables. The Coopersmith Self-Esteem Score and "feelings" score had a slightly weaker but still significant correlation with motor performance. The results suggest that poor performance on biomechanical testing in this population may be a form of abnormal illness behavior and thus may not accurately reflect organic alterations of neuromusculoskeletal function.

Adult↗
PubMedDate not supplied

Statistical packages for the Macintosh.

These programs represent the entry of the Mac into major statistical computing. We believe that for the physician researcher who is not a statistician, they make the Mac the platform for data analysis. We found that statistics, research design, and data analysis seemed different and much less intimidating to us and our trainees when approached through the Mac. We have reviewed the versions of these programs available at the time of this writing, in May 1992; potential buyers should contact the software publisher for information about more recent upgrades. At this point, our recommendations would be as follows: If you are wedded to SPSS or Minitab, try the Mac versions, and you will be impressed. Otherwise, the choice is between SYSTAT, which has been around long enough to demonstrate its richness and capacity to build on its strengths, and JMP, a brash newcomer, which demonstrates that you can teach an old dog (SAS) new tricks. StatView and SuperANOVA, while endowed with intuitive, easy-to-use interfaces, lack online help--a feature we consider important in a statistics package. We anticipate that the future will lead to simplification of the SYSTAT interface and the addition of more analytic capacities to JMP--and who knows what the next generation of competitors will bring?

Computer Systems↗