Banning live patients as test subjects on licensing examinations

The use of live patients on the licensing examinations was a part of dentistry for almost the entire twentieth century and continues up until today. Considerable new debate about the appropriateness of using live patients as test subjects began in the mid-1990s and culminated in the passage of a resolution in the American Dental Association's year 2000 House of Delegates calling for an end to this practice by the year 2005. The live patient examination tests a narrow range of clinical skills, creates ethical dilemmas for candidates, for the host institution, and for the profession, and is unable to distinguish between those ready to assume independent practice from those who are not yet at that level of competence. There are other ways to test for such readiness including proposals in New York State to substitute a postdoctoral year or mannequins in place of live subjects. The public and the dental profession will be better off by developing alternative licensing tests to the use of live subjects.     

The repeatability of an intraoral dental colorimeter

STATEMENT OF PROBLEM: Characterizing and reproducing color remain one of the most challenging aspects of dentistry. A relatively new intraoral colorimeter measures the color of natural teeth and metal-ceramic restorations and prints out a color recipe for the Vintage Halo Porcelain System. The reliability of the colorimeter is unknown. PURPOSE: The purpose of this study was to evaluate the reliability of a contact dental colorimeter and to correlate the shade registered by the colorimeter with the shade selected by experienced clinicians. MATERIALS AND METHODS: In part I of the study, 2 examiners (A and B) took 2 colorimeter measurements from the maxillary right central incisors of 11 subjects. The examiners were blinded to their own data and those of other investigators. The readings were repeated 3 weeks later with the same protocol. The Cronbach alpha reliability coefficient was used to analyze the collected data. In part II of the study, 2 experienced clinicians (examiners D and E) selected a shade from the classic Vita Lumin Vacuum shade guide for the maxillary right central incisors of the same 11 subjects. The clinicians were blinded to each other's selections and the colorimeter readings. It should be noted that the manufacturer of the colorimeter uses the terms shade, value, and hue to represent chroma, value, and hue, respectively, as defined in the Glossary of Prosthodontic Terms (J Prosthet Dent 1999;81:39-110). RESULTS: The reliability analysis results for each of the combined trials for shade, value, and hue were all >.94. The interexaminer reliability alpha values were >.9 for shade and value and.64 to.74 for hue. The interexaminer alpha represented the value range of each of 4 measurements. The intraexaminer reliability alpha values for shade, value, and hue were.99,.95, and.96 for examiner A and.99,.93, and.97 for examiner B, respectively. In part II of the study, the colorimeter agreed with itself 82% of the time, whereas clinicians agreed with each other on the selected shade 73% of the time. Selections made by the colorimeter and the clinicians matched 55% to 64% of the time. CONCLUSIONS: Within the limitations of this study, the colorimeter reliably measured the color of natural teeth.     

Peripheral deletion of autoreactive CD8 T cells by cross presentation of self-antigen occurs by a Bcl-2-inhibitable pathway mediated by Bim

By transgenic expression of ovalbumin (OVA) as a model self antigen in the beta cells of the pancreas, we have shown that self tolerance can be maintained by the cross-presentation of this antigen on dendritic cells in the draining lymph nodes. Such cross-presentation causes initial activation of OVA-specific CD8 T cells, which proliferate but are ultimately deleted; a process referred to as cross-tolerance. Here, we investigated the molecular basis of cross-tolerance. Deletion of CD8 T cells was prevented by overexpression of Bcl-2, indicating that cross-tolerance was mediated by a Bcl-2 inhibitable pathway. Recently, Bim, a pro-apoptotic Bcl-2 family member whose function can be inhibited by Bcl-2, was found to play a critical role in the deletion of autoreactive thymocytes, leading us to examine its role in cross-tolerance. Bim-deficient T cells were not deleted in response to cross-presented self-antigen, strongly implicating Bim as the pro-apoptotic mediator of cross-tolerance.     

Nonlinear acoustics in diagnostic ultrasound

The propagation of ultrasonic waves is nonlinear. Phenomena associated with the propagation of diagnostic ultrasound pulses cannot be predicted using linear assumptions alone. These include a progressive distortion in waveform, the generation of frequency harmonics and acoustic shocks, excess deposition of energy and acoustic saturation. These effects occur most strongly when ultrasound propagates within liquids with comparatively low acoustic attenuation, such as water, amniotic fluid or urine. Within soft tissues, similar effects occur, although they are limited by absorption and scattering. Nonlinear effects are of considerable importance during acoustic measurements, especially when these are used to predict in situ exposure. Harmonic generation may be used to create images. These offer improvements over conventional B-mode images in spatial resolution and, more significantly, in the suppression of acoustic clutter and side-lobe artifacts. B/A has promise as a parameter for tissue characterisation, but methods for imaging B/A have shown limited success.     

Low-dose flutamide-metformin therapy reverses insulin resistance and reduces fat mass in nonobese adolescents with ovarian hyperandrogenism

Ovarian hyperandrogenism is a common disorder often presenting post menarche with anovulatory oligomenorrhea and signs of androgen excess. Associated hyperinsulinemic insulin resistance, dyslipidemia, and central fat excess herald long-term disease risk. Combined antiandrogen (flutamide 250 mg/d) and insulin-sensitizing (metformin) therapy has beneficial effects, in particular on dyslipidemia and androgen excess in young women. We studied the effects of low-dose flutamide-metformin combination on metabolic variables and body composition in adolescent girls with ovarian hyperandrogenism. Thirty teenage girls (age range, 13.6-18.6 yr) with hyperinsulinemic hyperandrogenism participated in a 12-month pilot study with a 3-month off-treatment phase and a 9-month treatment phase (randomized sequence) on combined flutamide (125 mg/d) and metformin (1275 mg/d). Body composition was assessed by dual-energy x-ray absorptiometry; endocrine-metabolic state and ovulation rate were screened every 3 months. Insulin sensitivity was assessed by homeostasis model assessment (HOMA). Overnight GH and LH profiles were obtained pretreatment and after 6 months on treatment (n = 8). Over the 3-month pretreatment control phase (n = 14) all study indices were unchanged. Flutamide-metformin treatment (n = 30) was followed within 3 months by marked decreases in hirsutism score and serum androgens, by a more than 50% increase in insulin sensitivity and by a less atherogenic lipid profile (all P < 0.0001). After 9 months on flutamide-metformin, body fat decreased by 10%, with a preferential 20% loss of abdominal fat; conversely lean body mass increased, and total body weight remained unchanged; ovulation rate increased from 7-87% after 9 months. Baseline GH hypersecretion and elevated serum IGF-1 normalized after 6 months on flutamide-metformin. Within 3 months post treatment (n = 16), a rebound was observed for all assessed indices. In conclusion, in teenage girls with ovarian hyperandrogenism, low-dose combined flutamide-metformin therapy attenuated a spectrum of abnormalities, including insulin resistance and hyperlipidemia. Improved insulin sensitivity and reduced androgen activity led to a marked redistribution of body fat and lean mass, resulting in a more feminine body shape.     

Economic evaluation of programs or interventions in the management of rheumatoid arthritis: defining a consensus-based reference case

Improvement in the quality of economic evaluation could be documented as a consequence of international and national standardization efforts. One such effort is the recommendation that all economic evaluations in a given field produce findings in a standard format using a reference case. A reference case-based economic evaluation would adhere to specific settings with regard to outcomes, comparators, modeling techniques, and use of costs to facilitate comparisons among economic evaluations performed with the same objective. In the past, the Outcome Measures in Rheumatology Clinical Trials (OMERACT) consensus conference has successfully developed widely used, consensus-based outcome criteria for clinical improvement in rheumatoid arthritis (RA). Present efforts are being directed at the development of recommendations for the type and format of a reference case economic evaluation for newly developed disease modifying antirheumatic drugs (DMARD). This document discusses 13 important elements that experts considered to be relevant for the development of a reference case recommendation for economic evaluations in RA. We provide the rationale for each element and discuss how each element has been addressed in published economic evaluations of DMARD.     

Case mix use in 25 countries: a migration success but international comparisons failure

Diagnosis related groups (DRGs) were the first health management tool to group patients in clinical meaningful categories with homogeneous resources consumption. They belong to case mix measures that have been introduced in the USA in the seventies to identify clinical differences in groups of patients as well as to document variation in hospitals and physicians practices by comparing similar groups with each others. They are also used to adjust payment rates and to improve quality of care. This innovative concept migrated from the USA to several Western European countries and to Australia first, to Eastern Europe and Asia soon thereafter. The main objective in most countries concerns a hospital financing new methodology, based on similar groups of patients, by applying a global budget. The main result of this international overview of 25 countries is to show the difficulty to make international comparisons, mainly because of the absence of a universal classification system for procedures. Furthermore, diagnostic classification systems to group patients vary also by country. These obstacles to compare hospital and physician practices have profound roots in cultural differences and in political sensitivity for organising health care delivery between countries. The development of an appropriate Case Mix grouper tool including uniform diagnoses and procedures codes, leading to international use becomes a public health priority.