Expert performance in low-back disorder recognition using patient pain drawings.

Eight low-back-pain experts who regularly include pain drawings in their clinical workup were asked to classify 25 drawings. The experts used only the drawings to place cases into one of five broadly defined diagnostic categories: benign disorder, herniated disc, spinal stenosis, underlying disorder, or psychogenic disturbance. The physicians demonstrated adequate accuracy--51% correct--when compared with change (20% correct). Classification accuracy was greatest for psychogenic disorders (85%), followed by spinal stenosis (58%), herniated discs (52%), and benign disorders (50%). Predictions were comparatively poor for the underlying disorder category (10%). The individual physician accuracies varied from 44 to 60%. "Classic" pain patterns for each disorder group were identified by determining which drawings were correctly classified by most physicians. Physicians may wish to impart greater significance to pain drawings close to one of our "classic" patterns than to others.     

External gamma-ray counting of selected tissues from a Thorotrast patient.

Results of gamma-ray measurements of selected tissues from a patient who was injected with Thorotrast almost 36 y ago are reported. The purposes of this study were: 1) to determine the relative tissue distribution and activities of specific radionuclides in the 232Th decay chain, specifically 228Ra (as measured by 228Ac), 212Pb, and 224Ra (measured directly and as measured by 212Pb), and 2) to evaluate the level of radioactive disequilibrium among the daughter products. The spleen and liver had the highest concentrations of radioactivity. Bone also appears to be a long-term sink for 232Th daughter products based on estimates from a small portion of one rib. Larynx and esophagus contained measurable activity, which may have been due to their proximity to the "Thorotrastoma." Radioactivity in the remaining measured tissues were low, as expected. Secular equilibrium could be demonstrated in bone, pancreas, larynx, esophagus, and breast. Significant disequilibrium was observed for spleen, liver, kidney, and red blood cells. Radioactivity measurements reported here will be useful in estimating radiation doses to selected tissues. Such dose estimates are valuable in refining current risk estimates (e.g., liver) and in identifying tissues at risk for further epidemiologic studies. These results, while consistent with other published studies, should be interpreted with caution since measurements were made on only one patient.     

Effects of hydration and dehydration on body composition analysis: a comparative study of bioelectric impedance analysis and hydrodensitometry.

Since 1983, bioelectric impedance has been researched with respect to its validity and reliability in the determination of body composition. It continues to be compared to hydrostatic weighing, the anthropometric "gold standard". This study was designed to investigate the relationship between bioelectric impedance analysis (BIA) and hydrodensitometry (HW) under three conditions: control, hydration and dehydration. Caucasian males (aged 18-44 years) served as subjects (n = 10). Body composition was determined by BIA and HW before intervention, 30 minutes post-hydration, and following a combination of exercise and sitting in a steam room to decrease body weight by two to four percent (mean = 2.81%). Statistical treatment by two-way analysis of variance for repeated measures revealed that although there were no significant differences between the two techniques of body composition determination under any of the three conditions, there was a statistically significant decrease in percent body fat determined in the dehydrated state as compared to the control and hydrated conditions. Recommendations include the determination of hydration state prior to engaging in body composition analysis by either method.     

Neurosurgery image manager

Computer technology has become standard in many areas of medical practice, but computer-assisted instruction has not replaced standard textbooks and didactic lectures. This paper describes the development of a computer image-based educational system designed for neurosurgical instruction. The advantages and applications of this system for both clinical and academic use and the required software and hardware requirements are delineated. This computerized tutorial can organize and manipulate large amounts of data. The Neurosurgery Image Manager system contains an introductory help section, a self-assessment test in neurosurgery, and a data base of images from the video disc "The Slice of Life," produced at the University of Utah. Questions are taken from the Self-Assessment in Neurological Surgery series. Additionally, the system contains a reference index for all material in the tutorial, a scored clinical problems section, and a several hundred word glossary. The system is programmed using the Macintosh Hypercard authoring system. Large data bases can be manipulated and linked with graphics, text, and peripherals. Images are stored using the MacVision II digitizing system. The hardware necessary to operate the system and the method of implementation of Neurosurgery Image Manager are described. The prototype Neurosurgery Image Manager has been accepted by the Joint Committee on Education of the American Association of Neurological Surgeons and Congress of Neurological Surgeons as one of the computer formats for the next self-assessment tests.     

H1 and H2 receptor antagonists and hepatic oxygen supply-demand relationship in pigs

The hypothesis that histamine receptor (H1 and H2) blockade beneficially affects the hepatic oxygen supply-demand relationship was tested during experiments performed on 13 miniature pigs. Hepatic arterial and portal blood flows were measured with electromagnetic flowmeters. Cardiac output was determined by thermodilution. H1 and H2 receptor blockade was achieved with promethazine, 5 mg.kg-1 and cimetidine 30 mg.kg-1 IV, respectively. The study demonstrated no significant effect of H1 and H2 receptor blockade on hepatic oxygen uptake and no noticeable effects of cimetidine on hepatic circulation. However, promethazine decreased total hepatic blood flow, primarily by decreasing portal blood flow; this resulted in an increase in oxygen extraction as reflected in a decreased oxygen content in hepatic venous blood. The results reject the posed hypothesis: H1 receptor antagonist promethazine decreased, while H2 receptor antagonist cimetidine did not affect hepatic blood flow and oxygen supply; hepatic oxygen demand remained unaffected during H1 and H2 receptor blockade.     

Roux-Y Gastric Bypass: an effective anti-reflux procedure

Gastric limiting procedures have made an improvement in the lives of those patients in whom they have been successful. Not only have there been marked improvements in diabetes, hypertension, and arthritis, but there have been a number of other ‘spin-offs’, not the least of which is control of reflux esophagitis by totally eliminating the secretion of the parietal cell mass of the stomach from rising into the esophagus. We compared a group of 100 obese patients with reflux esophagitis who underwent Roux-Y gastric bypass (RYGBP) to a normalsized group of 23 patients on whom we had done Nissen fundoplications in the past. Visick gradings I-II of 100% vs 87%, respectively, may indicate a superiority of RYGBP over the Nissen procedure. Although the groups and time periods are too divergent to draw statistically significant conclusions, one can see that the RYGBP population was apparently better served considering their cure of ‘heartburn’ and other reflux symptoms as well as their achievement of sustained weight loss.     

Analysis of the genes involved in the insulin transmembrane mitogenic signal in Chinese hamster ovary cells, CHO-K1, utilizing insulin-independent mutants.

CHO-K1 cells, wild type (WT), grow in a defined medium with insulin as the only essential hormone. When starved for insulin, these cells accumulate in G0/G1 stage. Insulin binding to its receptor stimulates DNA synthesis and cell division and induces an increase in abundance of mRNA for c-fos, c-jun, Krox-20, Krox-24 (zif/268), fra-1, jun-B, c-myc, and JE. The kinetics of induction of these genes are similar to that shown with serum induction of 3T3. These genes show maximum stimulation at insulin concentrations of 20, 160, or 320 ng/ml and their expression is inhibited at higher concentrations. The addition of cycloheximide results in superinduction. The WT and insulin-independent mutants show no detectable signal for KC, fos-b, or nur77 and no increase over the basal level of pI-15, probably eliminating these genes as participants in the insulin mitogenic signal. These mutants synthesize DNA in the absence of insulin at rates that vary from 4 to 12 times that of the quiescent (insulin unstimulated) WT and are further inducible by insulin. The mutants have "constitutive" levels of Krox-24 (zif/268), fra-1, jun-B, c-myc, and JE (INS-type 2 genes) mRNAs that vary from mutant to mutant, reaching a maximum of an 8-fold increase for fra-1 and JE over the quiescent WT levels. There were no detectable levels of mRNA for genes c-fos and Krox-20 and no increase in level of mRNA for c-jun (INS-type 1 genes) as compared to the quiescent WT. Thus, although these INS-type 1 and type 2 genes may be involved in the full insulin mitogenic signal, the constitutive up-regulation of only genes in INS-type 2 is sufficient for insulin-independent DNA synthesis and cell division. Analysis of hybrids constructed between WT and mutant 27 indicate that the mutant phenotype is recessive, pointing to the existence of a regulatory gene producing a negative regulator.     

Measuring input prices for physicians: the revised Medicare Economic Index

Medicare payments for physician services under Part B were historically restrained by capping prevailing charges using the Medicare Economic Index (MEI). The MEI, an input price index for physician services that incorporates an adjustment for economywide labor productivity, has not undergone a major revision since 1975. The MEI is an important determinant of the annual volume performance standard that will be used to set aggregate increases in the revised system for paying physicians under Medicare beginning in 1992. The MEI will also be used in establishing the annual changes to the payment conversion factors under the new payment system.