[The medical uncertainty--an overlooked reality].
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False Negative Reactions↗
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Results for “Reality Testing”
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[Not confusing estimates with reality].
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Confidence Intervals↗
Myths and realities of the BCG vaccine in the pediatric population.
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Adult↗
The political reality of underwriting issues.
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Genetic Markers↗
Advanced surgical technologies for plastic and reconstructive surgery.
Virtual reality creates a simulated world in which the surgeon can practice and plan complex surgical procedures. This simulated world can be especially valuable in head and neck surgery, including congenital craniofacial surgery, facial trauma, and resection and reconstruction of head and neck tumors, whereby the complexity of the anatomy and the difficulty of the problems test the surgeon's abilities. The author presents a brief history of simulations and surgery, a background to plastic surgery simulators, and discuss the problem of limited human body models in past systems. Computer-aided surgery and virtual reality technologies are also reviewed.
Computer Simulation↗
A measurement of the process of adolescence: standardization and interpretation.
The Objective Measure of Ego Identity Status (Adams, Shea, & Fitch, 1979) was administered to 350 adolescents (12 to 18 years old) to test the Eriksonian theory of a developmental continuum from role diffusion to identity achievement. The results offer construct validity for the dynamic process proposed by Blos and Erikson, but do not support the categorization procedure as set forth by Adams, Shea, and Fitch. The OMEIS questionnaire lends itself to a qualitative and dynamic interpretation rather than to a quantitative and normative approach. It is suggested that the dynamic interpretation is more sensitive to the psychological reality of the developmental process.
Achievement↗
Mouse and man: multiple genes and multiple autoantigens in the aetiology of type I DM and related autoimmune disorders.
Autoimmunity to the pancreatic beta cell appears to be a chronic disorder which in some individuals progresses to overt type I diabetes [1]. Studies of offspring or siblings of patients with type I diabetes (IDDM) and discordant twins who have been followed for over 30 years are shedding new light on the disorder. Recent advances in molecular biological techniques have resulted in our ability to identify novel autoantigens and rapidly develop sensitive and specific tests to detect beta cell autoimmunity. The ability to cost-effectively screen the general population for diabetes susceptibility is rapidly becoming a reality. Animal models of diabetes such as the non-obese diabetes (NOD) mouse have provided insights into both pathogenesis of this disease and potentially into the prevention of diabetes as well. We will attempt to use our knowledge gained from studies of man and the NOD mouse to illustrate what we know and need to learn in order to prevent type I diabetes.
Animals↗
Common daily activities in the virtual environment: a preliminary study in parkinsonian patients.
Patients with Parkinson's disease (PD) create behavioral motor strategies by using external cues to facilitate their movements. Virtual reality (VR) could work as an external stimulus in order to explore the motor plans by means of creation of mental images. We tested 2 women with PD aged 68 and 69 years, and 10 normal control subjects. Patients underwent a neuropsychological assessment to evaluate cognitive abilities involved in the tasks required by the VR session. VR environment reproduces common daily activities situations at home, such as eating or using the bathroom. VR describes the alterations of the motor plans in PD by a point of view different from the clinical one, by testing "pure" mental sequences of the execution of a movement, without the interference of motor disability.
Activities of Daily Living↗
Screening for prostate cancer: opportunities and challenges.
Prostate cancer screening with PSA and with digital rectal examination isa reality in the United States. Regardless of recent observations regarding the complexities of PSA interpretation, millions of U.S. men expect an annual PSA test and physicians have come to rely on the test, in combination with digital rectal examination, to assess for prostate cancer risk. What has become evident is that PSA can no longer be interpreted dichotomously as a simple yes or no. The test reflects a range of risk and PSA value must be merged with other risk factors of an individual man including ethnicity, family history, as well as the individual's risk aversion to complications from prostate cancer. The future of prostate cancer screening will be built upon incorporation of new biomarkers to the prediction of risk of disease. As these markers move forward in testing, it will no longer be acceptable to move these into clinical usage without formal validation studies and, because of the high frequency of prostate cancer in the general male population, these validation studies will almost certainly have to include measures of prognosis. It is the holy grail of cancer biomarker development to acquire a test that is positive in the man with clinically-aggressive prostate cancer but is negative in both the patient without disease and in the man with disease that will be of no clinical consequence over his lifetime.
Adenocarcinoma↗
Non-invasive atherosclerosis imaging: use to assess response to novel or combination lipid therapies.
Despite significant protection from cardiovascular events by HMG-CoA reductase inhibitors (statins), the extent of event reduction is incomplete and persistent lipid abnormalities remain prevalent. As such, the use of combination lipid modification regimens is a clinical reality. While we await large, randomized clinical outcomes trials assessing the benefits of combination or novel lipid management therapies, non-invasive imaging tests such as B-mode ultrasound to measure carotid intima-media thickness (CIMT), coronary computed tomography (CT) and cardiovascular magnetic resonance imaging (CMR) are increasingly being utilized to accurately assess the impact of lipid modifying therapies on atherosclerosis. Based on knowledge that atherosclerosis progression is a validated surrogate for increased cardiovascular risk, use of atherosclerosis imaging surrogates in studies allows for smaller sample sizes, shortens study duration, demonstrates clinically meaningful changes prior to clinical event and provides potentially useful pathophysiologic information. CIMT measurement is currently the most studied and validated non-invasive imaging study used to assess atherosclerosis longitudinally in response to lipid modification therapies. Quantification of coronary calcium using coronary CT has been utilized to study atherosclerosis longitudinally, however, calcium scoring to assess response to lipid modifying therapies is not recommended due to several limitations of this assessment of the atherosclerosis process. These include the fact that non-calcified atherosclerosis is not quantified, that the calcification process in atherosclerosis is diverse and that the effects of statins on tissue calcification are complex. Use of contrast coronary CT to image non-calcified coronary atherosclerosis is promising. Modern CMR imaging, aided by high reproducibility and image resolution, is rapidly advancing and early studies imaging non-coronary and coronary atherosclerosis are impressive.
Atherosclerosis↗
Evaluation of INPRES--Intraoperative Presentation of surgical planning and simulation results.
In this paper we present fundamental results of the first evaluation of INPRES in a laboratory environment. While the system itself--an HMD-based approach for intraoperative augmented reality in head and neck surgery--has been described elsewhere several times, this paper will focus on methods and outcome of recently accomplished test procedures.
Humans↗
[Suspicion on sulfites].
The sulfites have anti-oxygen and anti-microbial properties, which explain their great use in the food and drug industry. They may be responsible for anaphylactoid type episodes or more often asthmatic crises. 4 to 8% of asthmatics are sensitive to sulfites. The majority of asthmatics who are sensitive to sulfites are steroid dependent asthmatics. The pathophysiology is not clear: either a reaginic mechanism, reflex bronchoconstriction to SO2, a partial deficit in sulfite-oxidases. The diagnosis rests on oral provocation tests. These tests should be carried out according to a rigorous methodology, because there are frequent false positives (57 to 70%). Tests of alimentary provocation do not always correlate with the results from oral provocation tests to sulfites and pose the double question of sensitivity to the combined forms of sulfites which are present in food, and the reality of the risk of exposure of asthmatics to these foods. The prevention of any such mishaps rests on the eviction of such substances from the food which is often difficult and also of drugs. Vitamin B12, atropine, doxepin and sodium cromoglycate are capable of preventing totally or partially the bronchospasm induced by the absorption of sulfites.
Anaphylaxis↗
Revision of the structure for an endo-beta-N-acetylglucosaminidase H substrate using a novel modification of the Smith degradation.
(Man)5(GlcNAc)2Asn was shown in a previous study (Trimnble, R. B., Tarentino, A. L., Plummer, T. H., Jr., and Maley, F. (1978) J. Biol. Chem. 253, 4508-4511) to be hydrolyzed by alpha-mannosidase to Man alpha 1 leads to 6Man alpha 1 leads to 6(Man alpha 1 leads to 3)Man beta 1 leads to 4GlcNAc beta 2 leads to 4GlcNAc-Asn. The latter is the most effective substrate for endo-beta-N-acetylglucosaminidase H tested to date. By employing a new and highly sensitive modification of the Smith degradation, it is shown that this compound is in reality Man alpha 1 leads to 6(Man alpha 1 leads to 3)Man alpha 1 leads to 6Man beta 1 leads to 4GlcNAc beta 1eads to 4GlcNAc-Asn. The method entails the conversion of a glycosyl asparagine derivative to its corresponding dimethylaminonaphthyl sulfonyl analogue, which after periodate oxidation is treated directly with Dowex 50-H+ to eliminate the modified carbohydrate residues. The dansylated products, which are eluted from the resin with ammonium hydroxide, can be identified rapidly by thin layer chromatography.
Acetylglucosaminidase↗
[Latex and pollinosis].
Through the multidetection test for specific IgE to pneumoallergens (Aero-Matrix Plus, Abbott) our attention has been drawn to polysensitization to pollens. Amongst these pollen tests, plantain seems to be frequently associated with sensitization to latex. The aim of this work at first, is therefore to verify the reality of the frequency of the association between latex and plantain sensitization. However, the conclusions are difficult, since there are no patients who are only sensitive to plantain as sensitivity to this allergen is always found in a pollen polysensitization. at least associated with grass pollens; at most associated with a number of other pollens. The double profile (perhaps plantain + / grass pollen +, or perhaps plantain + / grass pollen + / other pollens +) is determinant in prediction of sensitivity to latex, which is found essentially in the group plantain + / grass pollen + / other pollens +. This study has also shown that amongst the population who have specific IgE to latex (IgEs) (sensitized or allergic): the patients who have a clinical history of allergy to latex have no profile of pollen polysensitization; the non-allergic but sensitive patients (IgE positive, but no clinical signs on contact with latex) show an extreme pollen polysensitization. This poses a problem of different antigenic determinants or perhaps two different pathways to sensitization to latex.
Allergens↗
Evaluating the burst hypothesis at a site-specific level using the lack-of-fit test.
It has been hypothesized that periodontal disease progresses by means of sudden losses of periodontal attachment surface area. Obtaining reliable tests of this burst hypothesis has proven to be difficult; the signal (true model of disease progression) often gets lost in the noise. The purpose of this study was to determine how reliably we could distinguish sudden changes from linear disease progression at a site using a time series of clinical attachment levels. Specifically, the following question was investigated: If, in reality, disease progresses by means of sudden changes in clinical attachment level (bursts), and a linear model is fitted to these data, what is the likelihood of rejecting the linear model using the lack-of-fit test? This likelihood was determined as a function of the probing measurement error (range: 0.2 to 1.0 mm) and the number of clinical examinations over time. The results suggested that bursts of 2 mm or smaller cannot be reliably distinguished from linear disease progression using the lack-of-fit test, except under unusual clinical circumstances. Under typical clinical circumstances, burst sizes needed to be 3 to 5 mm in order to be reliably distinguished from linear disease progression. These results are probably overly optimistic. The ability to verify the burst hypothesis at the site level is likely to be even less than our results indicate because of various assumptions that were required. We conclude that the lack-of-fit test will reliably reject the linear model at a site-specific level only if true disease progresses in such a fashion that a handful of sudden changes leads to a tooth mortality event.
Algorithms↗
The fate of the medically castrated testis: expectation versus reality.
PURPOSE: Cosmetic expectation has a major role in influencing patient choice between medical and surgical castration, and yet to our knowledge the fate of the medically castrated testis has never been accurately tested and documented in the literature. We determined the weight of testes in patients receiving medical castration and compared it to that in a control group receiving primary surgical castration. MATERIALS AND METHODS: We performed a retrospective analysis of 88 patients with prostate cancer who underwent bilateral simple orchiectomy with epididymal sparing. The study was done at Veterans Administration Medical Center, Atlanta, Georgia. All procedures were performed using local anesthesia in an outpatient clinical setting. Patients were divided into 2 groups, namely 52 receiving luteinizing hormone releasing hormone (LH-RH) agonist therapy prior to the procedure and 36 controls who were not. The weight of the testes was compared between the 2 groups. RESULTS: Median testicular weight significantly decreased following treatment with LH-RH agonist compared to the control group. Median weight of the testis was 7.0 gm (range 0.5 to 22.0) in the LH-RH agonist group compared to 15 gm (range 4.0 to 44.0) in the control group (p = 0.0049 x 10). CONCLUSIONS: Medical castration with LH-RH agonist therapy significantly decreases the weight of testes and compromises the cosmetic outcome. Since cosmetic expectation has a major role in influencing patient choice between medical and surgical castration, patients should be fully informed about the significant testicular atrophy associated with medical castration before making their decision.
Androgen Antagonists↗
How to test very soft biological tissues in extension?
Mechanical properties of very soft tissues, such as brain, liver and kidney, until recently have largely escaped the attention of researchers because these tissues do not bear mechanical loads. However, developments in Computer-Integrated and Robot-Aided Surgery - in particular, the emergence of automatic surgical tools and robots - as well as advances in Virtual Reality techniques, require closer examination of the mechanical properties of very soft tissues and, ultimately, the construction of corresponding, realistic mathematical models. A body of knowledge about mechanical properties of very soft tissues, assembled in recent years, has been almost exclusively based on the results of compression, indentation and impact tests. There are no results of tensile tests available. This state of affairs, in the author's opinion, is caused by the lack of analytical solution relating a measured quantity - machine head displacement - to strain in simple extension experiments of cylindrical samples with low aspect ratio. In the paper this important solution is presented. The theoretical solution obtained is valid for isotropic, incompressible materials for moderate deformations (<30%) when it can be assumed that planes initially perpendicular to the direction of applied extension remain plane. Two astonishing results are obtained: (i) deformed shape of a cylindrical sample subjected to uniaxial extension is independent on the form of constitutive law, (ii) vertical extension in the plane of symmetry lambda(z) is proportional to the total change of height for strains as large as 30%. The importance and relevance of these results to testing procedures in Biomechanics is highlighted.
Animals↗
Quantitative techniques for stress echocardiography: dream or reality?
Stress echocardiography is now an everyday clinical tool. However, the substantial evidence base that supports its use is largely derived from expert centres, and concerns have been expressed about the performance of the test in less expert hands. A unifying feature of the problems of stress echocardiography is its subjective assessment. This review examines the consequences of qualitative interpretation and the benefits of developing a quantitative approach. Although no quantitative approach is in widespread clinical use, several alternative techniques are feasible, and this area warrants further study.
Clinical Trials as Topic↗