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Biomedical subjects

R Renard

Publications and source records attributed to R Renard.

8 recordsLinked to original sources
PubMed2001

Effect of displacement of fractures of the greater tuberosity on the mechanics of the shoulder.

Using a dynamic biomechanical model of malunion of the shoulder, we have determined the change in deltoid force required for abduction with various combinations of superior and posterior displacement of fractures of the greater tuberosity of the humerus. We tested eight fresh human cadaver shoulders in a dynamic shoulder-testing apparatus during cycles of glenohumeral abduction from 0 degrees to 90 degrees. The greater tuberosities were osteotomised and stabilised to represent malunion with combinations of superior and posterior displacements of 1 cm and less. The peak force was measured for each displacement in each specimen and statistically compared with values of no displacement using a repeated-measures analysis of variance. The abduction force was significantly increased by 16% (p = 0.006) and 27% (p = 0.0001) by superior displacements of 0.5 cm and 1 cm, respectively, while combined superior and posterior displacement of 1 cm gave an increase in force of 29% (p = 0.001). While treatment criteria for acceptable residual displacement of the greater tuberosity are widely used, there is little information on the direct biomechanical effects of displacement on shoulder mechanics. Although the results of conservative treatment are influenced by a number of factors, including associated injuries, rehabilitation and the pre-existing function of the shoulder, our data suggest that small amounts of residual displacement may alter the balance of forces required to elevate the arm at the glenohumeral joint.

Adult↗
PubMed2000

A scale of methodological quality for clinical studies of radiologic examinations.

PURPOSE: To develop and evaluate a scale for assessment of the methodological quality for clinical investigations of radiologic studies. MATERIALS AND METHODS: A scale was developed that included methodological standards compiled from established sources for assessing the methodological quality of study designs in clinical research and characteristics related to biases commonly observed in clinical radiologic research. The scale was composed of 15 standards and was tested with the results of 96 studies on imaging of liver hemangioma. Interrater reliability was measured between two observers by using percentage agreement and kappa statistics. Interrater reliability between two observers for a composite quality index that encompassed the 15 standards was measured with the intraclass correlation coefficient. RESULTS: Agreement between the two observers was almost perfect (kappa value, 0.8-1.0) for 11 standards and substantial (kappa value, 0.74-0.78) for four standards. Agreement between the observers with regard to the composite quality index also was high (intraclass correlation coefficient r, 0.91 [95% CI: 0.87, 0.94]). CONCLUSION: The scale appears to be reliable for the assessment of methodological quality of clinical investigations of radiologic studies.

Hemangioma↗
PubMed2000

Interpretation of Emergency Department radiographs: a comparison of emergency medicine physicians with radiologists, residents with faculty, and film with digital display.

OBJECTIVE: We determined the relative value of teleradiology and radiology resident coverage of the emergency department by measuring and comparing the effects of physician specialty, training level, and image display method on accuracy of radiograph interpretation. MATERIALS AND METHODS: A sample of four faculty emergency medicine physicians, four emergency medicine residents, four faculty radiologists, and four radiology residents participated in our study. Each physician interpreted 120 radiographs, approximately half containing a clinically important index finding. Radiographs were interpreted using the original films and high-resolution digital monitors. Accuracy of radiograph interpretation was measured as the area under the physicians' receiver operating characteristic (ROC) curves. RESULTS: The area under the ROC curve was 0.15 (95% confidence interval [CI], 0.10-0.20) greater for radiologists than for emergency medicine physicians, 0.07 (95% CI, 0.02-0.12) greater for faculty than for residents, and 0.07 (95% CI, 0.02-0.12) greater for films than for video monitors. Using these results, we estimated that teleradiology coverage by faculty radiologists would add 0.09 (95% CI, 0.03-0.15) to the area under the ROC curve for radiograph interpretation by emergency medicine faculty alone, and radiology resident coverage would add 0.08 (95% CI, 0.02-0.14) to this area. CONCLUSION: We observed significant differences between the interpretation of radiographs on film and on digital monitors. However, we observed differences of equal or greater magnitude associated with the training level and physician specialty of each observer. In evaluating teleradiology services, observer characteristics must be considered in addition to the quality of image display.

Analysis of Variance↗
PubMed1988

Clinical relevance of the substitution of different brands of sustained-release theophylline.

In order to assess whether clinically important changes in serum theophylline concentrations occur when patients switch their brand of slow-release (SR) theophylline, 10 subjects with asthma were administered the same dose of four different SR theophylline formulations for 2-week periods in a random, double-blinded, crossover manner. Analysis of the data revealed significant differences in mean peak-to-trough fluctuations of serum theophylline concentrations between the formulations of SR theophylline, which varied from 60% to 106% of trough concentration (p less than 0.0001, analysis of variance). On at least one occasion in every subject, switching between brands of SR theophylline was responsible for raising the serum theophylline concentrations outside the accepted therapeutic range, and this was associated with symptoms of toxicity in five of the subjects. Worsening pulmonary functions were observed in two of the subjects whose switching resulted in lowered theophylline concentrations. Many of the formulation-related changes in theophylline concentrations appeared to be idiosyncratic and could not be predicted by the overall bioavailability differences between the drugs. These results argue against the open substitution of these formulations and suggest that if patients are switched between different brands of SR theophylline, their serum theophylline concentrations need to be closely monitored.

Adult↗
PubMed1985

[Say: Papa].

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Adult↗
PubMed1984

Rural-to-urban migration and the shadow wage in LDCs.

"This paper discusses the amount of rural-to-urban migration which will be forthcoming when a new urban job is created for which an institutionally fixed wage above the market-clearing level is offered. A simple formula is proposed to estimate migration response. It can be used to calculate the shadow wage in cost-benefit analysis (CBA) in less developed countries (LDCs)."

Cost-Benefit Analysis↗
PubMed1969

[Not Available].

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Argentina↗