Bone mineral density testing in healthy postmenopausal women. The role of clinical risk factor assessment in determining fracture risk.

The ease of measurement and the quantitative nature of bone mineral densitometry (BMD) is clinically appealing. Despite BMD's proven capability to stratify fracture risk, data indicate that clinical risk factors provide complementary information on fracture susceptibility that is independent of BMD. Methods to quantify fracture risk using both clinical and BMD variables would have great appeal for clinical decision-making. We describe a procedure for quantifying hip fracture risk (5-yr and remaining lifetime) based on (1) the individual's age alone (base model, assuming average clinical risk factors and bone density), (2) incorporation of multiple patient-specific clinical risk factor data in the base model, and (3) incorporation of both patient-specific clinical risk factor data and BMD results.     

Significant efficiency findings while controlling for the frequent confounders of CAI research in the PlanAlyzer project's computer-based,self-paced,case-based programs in anemia and chest pain diagnosis

Richard E. Clark in his widely published comprehensive studies and meta-analyses of the literature on computer assisted instruction (CAI) has decried the lack of carefully controlled research, challenging almost every study which shows the computer-based intervention to result in significant post-test proficiency gains over a non-computer-based intervention. We report on a randomized study in a medical school setting where the usual confounders found by Clark to plague most research, were carefully controlled. PlanAlyzer is a microcomputer-based, self-paced, case-based, event-driven system for medical education which was developed and used in carefully controlled trials in a second year medical school curriculum to test the hypothesis that students with access to the interactive programs could integrate their didactic knowledge more effectively and/or efficiently than with access only to traditional textual “nonintelligent” materials. PlanAlyzer presents cases, elicits and critiques a student's approach to the diagnosis of two common medical disorders: anemias and chest pain. PlanAlyzer uses text, hypertext, images and critiquing theory. Students were randomized, one half becoming the experimental group who received the interactive PlanAlyzer cases in anemia, the other half becoming the controls who received the exact same content material in a text format. Later in each year there was a crossover, the controls becoming the experimentals for a similar intervention with the cardiology PlanAlyzer cases. Preliminary results at the end of the first two full trials shows that the programs have achieved most of the proposed instructional objectives, plus some significant efficiency and economy gains. 96 faculty hours of classroom time were saved by using PlanAlyzer in their place, while maintaining high student achievement. In terms of student proficiency and efficiency, the 328 students in the trials over two years were able to accomplish the project's instructional objectives, and the experimentals accomplished this in 43% less time than the controls, achieving the same level of mastery. However, in spite of these significant efficiency findings, there have been no significant proficiency differences (as measured by current factual and higher order multiple choice post-tests) between the experimental and control groups. Very careful controls were used to avoid what Clark has found to be the most common confounders of CAI research. Accordingly, this research proved Clark's rival hypothesis, that the computer, in itself, does not appear to contribute to proficiency gains, at least as measured by our limited post-testing. Clark's position is that the computer is primarily a vehicle—as is either a pill or a hypodermic needle for delivering a drug. The hypodermic needle can deliver the drug more efficiently than can the pill, (as can the computer deliver the subject matter content more efficiently, as our research indicates), but the same content is delivered. At the same time, we proved our own hypothesis, as far as efficiency gains resulting from the computer are concerned. However, going beyond Clark's research, we may be teaching processes both more effectively and efficiently with the computer (experience in problem-solving or clinical reasoning and pattern recognition) which our current post-tests do not adequately measure. Our on-going research suggests additional inquiry in several areas: better evaluation instruments to measure the clinical reasoning skills PlanAlyzer was designed to teach; the addition of more advanced cases to determine if this might transform efficiency gains of the computer group into proficiency gains; the addition of enhanced graphic decision support tools and other pedagogical enhancements including cognitive feedback to strengthen PlanAlyzer's power to teach complex concepts of medical decision-making.     

Variability of coronary blood flow measurements with microspheres in the rat: role of injection site and sphere number

Although fully explored in larger animals, the role of injection site and sample microsphere content on variability of coronary blood flow (CBF) measurement using the microsphere technique remains controversial in rats despite the fact that this species is extensively used in cardiovascular research. We therefore investigated these variables in two studies. In a first study, we established that the precision of the method, assessed by the variability of four simultaneous CBF determinations, was a function of the sample microsphere number. Coefficient of variation (CV) averaged 4-10% when the tissue and reference samples received greater than 1000 and greater than 100 spheres, respectively, and did not improve appreciably with larger numbers of microspheres. In a second study, flow CV was measured following left atrial (LA) or left ventricular (LV) microsphere injections performed nearly simultaneously in the same conscious animal or in two similar groups of animals. CBF variability was lower by 22-62% after LA than after LV injections. Estimates obtained from separate analysis of the main variability components indicated that, with one exception, the variability associated with LV injections was at least 1.4 to 2.8 times higher than that due to LA injections. These findings establish the minimum number of microspheres needed to obtain precise blood flow determinations in the rat model and confirm previous reports, in anaesthetised rats, that LA microsphere injections generally yield more precise coronary blood flow determinations than LV injections.     

RN-BSN programs: associate degree and diploma nurses' perceptions of the benefits and barriers to returning to school.

The nursing profession is facing a serious shortage in all areas including BSN completion programs. The purpose of this study was to explore associate degree and diploma nurses' perceptions of the benefits and barriers to RN-BSN programs. In addition, factors that would facilitate degree completion in academia and work environments were examined.     

Pelvic Pain Complicating LHRH Analogue Treatment of Fibroids

We present these 3 cases to alert others to the possibility of severe pain with rapid shrinkage of fibroids occurring during LHRH analogue treatment. We suggest management of such events should not be surgical except for vaginal excision of prolapsed fibroid polyps.     

A rapid microtiter plate method for the detection of lysozyme release from human neutrophils.

An improved method was devised to measure lysozyme secreted from human neutrophils [polymorphonuclear leukocyte (PMN)] using a microtiter plate reader capable of analyzing enzyme kinetics. The assay is an adaptation of the classical photometric method which detects changes in the turbidity of a bacterial suspension, Micrococcus lysodeikticus, caused by the enzymatic activity of lysozyme. A standard curve using chicken egg white lysozyme was generated, and activity was detectable between the range of 1 and 100 ng/ml. Leukotriene B4 (LTB4)-induced lysozyme release from human PMN was comparable in both the standard assay and the microtiter plate adaptation with EC50 values of 6.5 and 7.2 nM, respectively. Other select stimuli and their receptor antagonists were also used to evaluate the method. Dose-response curves for chemotactic hexapeptide (CHP), recombinant human C5a (rhC5a), and platelet-activating factor (PAF) resulted in EC50 values of 0.14, 0.80, and 542.00 nM, respectively. Inhibition of lysozyme release was studied using receptor antagonists N-t-Boc-L-methionyl-L-leucyl-L-phenylalanine (N-t-Boc), LY223982, and protamine, which are putative inhibitors of formyl peptides (i.e., CHP), LTB4, and C5a, respectively. N-t-Boc inhibited CHP-induced (0.2 nM) enzyme release with an IC50 of 2 microM; LY223982 blocked LTB4-induced (20 nM) release resulting in an IC50 of 52 nM; and protamine inhibited rhC5a-induced (1.5 nM) release with an IC50 of 2 microM. Further studies revealed that CHP, LTB4, and rhC5a were selectively inhibited by their respective antagonists, albeit LY223982 and protamine were also weak inhibitors of CHP and LTB4, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)