Analytical and clinical evaluation of new diagnostic tests for myocardial damage

We tested the hypothesis that preventing cyclic GMP degradation with zaprinast, (a selective cyclic GMP-phosphodiesterase inhibitor) would produce a blunted reduction in myocardial O2 consumption in renal hypertension (One Kidney-One Clip, 1K1C)-induced cardiac hypertrophy. Four groups of anesthetized open-chest New Zealand white rabbits (n = 26) were utilized. Either vehicle or zaprinast (3 x 10(-3) M) was applied topically to the left ventricular surface of control or 1K1C rabbits. Coronary blood flow (radioactive microspheres) and O2 extraction (microspectrophotometry) were used to determine O2 consumption. Myocardial cyclic GMP levels were determined by radioimmunoassay. The 1K1C rabbits had a greater heart weight-to-body weight ratio (2.94 +/- 0.08 g/kg) than controls (2.58 +/- 0.17). Systolic blood pressure was higher in 1K1C (102 +/- 9 mm Hg) than in controls (86 +/- 3). Zaprinast significantly and similarly increased cyclic GMP in both control (3.90 +/- 0.47 to 4.66 +/- 0.89 pmol/g) subepicardium (EPI) and (5.08 +/- 0.69 to 7.06 +/- 1.36) subendocardium (ENDO) and 1K1C hearts (5.53 +/- 0.61 to 7.48 +/- 1.51 EPI and 6.48 +/- 0.42 to 8.88 +/- 1.08 ENDO). Myocardial O2 consumption (ml O2/min/ 100 g) was significantly lower in controls treated with zaprinast (EPI: 8.8 +/- 0.1; ENDO: 9.5 +/- 1.9) than in controls treated with vehicle (EPI: 13.6 +/- 1.3; ENDO: 16.2 +/- 2.9). This effect was diminished in 1K1C rabbits treated with zaprinast (EPI: 10.3 +/- 2.4; ENDO: 11.2 +/- 2.6) compared with the vehicle-treated 1K1C group (EPI: 13.3 +/- 1.2; ENDO: 14.5 +/- 2.4). There was a similar increase in myocardial cyclic GMP after treatment with zaprinast, but a greater depression of myocardial O2 consumption in control animals than in 1K1C after treatment with zaprinast. This suggested that the reduction in myocardial O2 consumption, related to increases in cyclic GMP caused by cyclic GMP-phosphodiesterase blockade, was less in 1K1C cardiac hypertrophy.     

Comparison of clinical diagnostic tests in hydrogel extended wear

In order to formulate a biosocial conception of tobacco dependence essential for fundamental grounding of smoking prevention, the authors examined 1106 subjects with smoking habits, smoking dependence and nonsmokers. A combination of internal and external factors is determined underlying the onset and maintenance of tobacco dependence. Risk factors responsible for consolidation of tobacco addiction are listed.     

Meta-analysis of screening and diagnostic tests.

Screening and diagnostic tests are common in the fields of psychology, medicine, and education. Often there are several competing tests, and decisions must be made about the relative accuracy of those tests. This article describes a general measure that can be used for both continuous and dichotomous outcome measures. It is the standardized distance between the means of the 2 populations. For continuous measures, it is the effect size measure. For dichotomous measures, it is proportional to the logarithm of the odds of the sensitivity plus the logarithm of the odds of the specificity. The measure is easily computed for both kinds of outcomes. Properties of this measure are discussed, and examples are given. The use of this measure to compare the average performance of different tests is described. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Ergometric tests in cardiology. Diagnosis of coronary insufficiency: methods and evaluated parameters

The historical development of the stress-test in the diagnosis of coronary insufficiency has been examined from the first observations about 1930 regarding changes in the repolarization phase during effort in coronary patients, up to modern tests with the ergometer bicycle and treadmill. Starting from the consideration that Master's Test is still the most commonly used in clinical practice, the limitations of tests of this type are highlighted and the discussion also covers the techniques and parameters now considered of greatest importance in cardiopathy diagnosis and evaluated by means of modern maximal stress tests. The results of a first period of work involving tests using the treadmill are reported. The methodology is discussed and the symptoms or ECG data that had suggested the test be used are related to the patient's origin (out-patient or hospitalized) and with the test's positivity or negativity. The high incidence of unstable ST syndrome, especially in the female sex, is also stressed. If this is not thoroughly investigated functionally (hyperventilation, Valsalva, etc.) it could be the cause of a large number of false positives. The lack of danger in the maximal stress test, even in cardiopaths, is confirmed together with the extreme ease with which nearly all patients manage to perform the test on the treadmill. Stress is also laid on the fact that the stress test is functional, unlike coronarography which is purely morphological, and the two examinations are thus complementary in the diversity of information they provide.     

Statistical applications for in vitro diagnostic tests and other medical device clinical trials

Some statistical methods applied to in vitro diagnostic tests for the three primary indications (screening, diagnosis, and monitoring) are discussed. Various examples with practical statistical applications are presented, including test for k by k ordered categorical matched-pair data for screening of cervical cancer, receiver operating characteristic (ROC) curve for diagnosis or screening, and the Cox time-to-event model to estimate relative risk of first cancer progression by monitoring carcinoembryonic (CEA) levels for stage IV breast cancer patients.     

Roaming through methodology. X. The testing of diagnostic procedures

In this era of evidence-based medicine, diagnostic tests cannot escape close scrutiny of their effectiveness. Sensitivity and specificity have up till now played a central role in the evaluation of diagnostic tests. These terms are not without their shortcomings when it comes to the characterisation of a test's true worth for patients. Randomised clinical trials are increasingly used for evaluation of medical tests and outlining of strategy. The indirect relationship between test results and health outcome creates additional challenges for designers of such trials.     

Some effects of combining psychological tests on clinical inferences.

The study was designed to determine whether the reliability and validity of interpretations based on 3 frequently used psychological tests—Rorschach, TAT, MMPI—increased as a function of number of tests employed. 30 clinical psychologists completed personality questionnaires describing 5 Ss on the basis of identifying data alone, each test individually, pairs of tests, and all 3 combined. Reliability and validity did not increase as a function of number of tests, nor were there any differences between tests or pairs of tests. The validity scores for test data ranged from 66% to 73%, with a Mean of 68%. The reliability scores ranged from 56% to 72%, with a Mean of 64%. (18 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pediatricians' diagnostic approach to pharyngitis and impact of CLIA 1988 on office diagnostic tests

OBJECTIVE: To determine the factors associated with an optimal diagnostic approach to a child with pharyngitis, characterize office laboratory methods for throat swab culture and group A streptococcal rapid antigen testing, and assess the potential impact of the Clinical Laboratory Improvement Amendments (CLIA) of 1988 on the performance of these tests. DESIGN AND SETTING: Mailed survey to all board-certified primary care pediatricians from seven western states with telephone follow-up for nonrespondents. OUTCOME MEASURES: Differences in practice characteristics and use of office laboratory tests for physicians who usually (> 80%) diagnose pharyngitis using a recommended approach vs those who follow this approach less often (< 50%); characteristics of physicians who indicate that they intend to discontinue office throat culture because of CLIA and those who will continue to perform this test also are compared. RESULTS: Responses from 531 pediatricians were analyzed. Forty-four percent diagnosed pharyngitis appropriately for more than 80% of patients, and 17% did so for fewer than 50%. Optimal diagnosis was significantly more common among physicians who cultured throat swabs in their office (relative risk, 1.40; 95% confidence interval, 1.19 to 1.66) and less common among solo practitioners (relative risk, 0.71; 95% confidence interval, 0.56 to 0.88). Factors that may decrease the sensitivity of office throat culture include short duration of incubation (59%), lack of quality control (51%), and limited education of the persons reading results (6%). With implementation of CLIA, 24% of pediatricians reported that they already have discontinued or will discontinue office throat culture, and 23% have discontinued or will discontinue antigen detection testing for group A streptococci. Those most likely to stop office culture include solo practitioners and practitioners who do not currently perform quality control of culture methods. CONCLUSIONS: Office culture for group A streptococci is strongly associated with an optimal diagnostic approach. Implementation of CLIA regulations may substantially decrease the number of physicians who perform this test. The balance between potential improvements in the quality of office culture with CLIA implementation and the decreased availability of this test needs to be assessed.     

Beyond the twelve-lead electrocardiogram: diagnostic tests in the evaluation for suspected acute myocardial infarction in the emergency department, part I

On a daily basis the emergency physician is faced with the difficult task of determining whether or not a patient with acute chest pain is sustaining an acute myocardial infarction. In most cases, this is not a straightforward decision. Although observation units are being used more often for chest pain evaluations, many emergency physicians currently admit such patients to an intensive care setting. Because fewer than one-third of emergency department chest pain patients actually suffer an acute myocardial infarction, expensive resources are, in retrospect, used unnecessarily. Conversely, patients who are infarcting, and are inadvertently discharged home from the emergency department, have a worse prognosis than those admitted. This two-part series reviews the newer modalities available that may help the emergency physician arrive at a more accurate diagnosis. The current article, Part I, examines the use of myocardial imaging, computer assisted diagnostic protocols, and newer uses of the electrocardiogram. Part II reviews the use of biochemical assays of cardiac proteins and the Chest Pain Observation Unit.     

Evaluating diagnostic tests in the pleural space. Differentiating transudates from exudates as a model

Physicians have a staggering variety of diagnostic tests available for directing their diagnostic and therapeutic decisions. Technologic advances in laboratory science have increased the sophistication of new tests and accelerated their rate of adoption into clinical practice. Unfortunately, studies that report the value of new diagnostic tests often fail to follow accepted methodologic standards for unbiased test assessment or provide clinicians with sufficient information for the intelligent evaluation of a test's performance and applicability. The following review of pleural fluid tests that discriminate between exudative and transudative effusions serves to highlight important methodologic considerations in the assessment of diagnostic tests.     

Interpretation of diagnostic laboratory tests in selected endocrine disorders

This article discusses various lab and diagnostic tests used in the diagnosis of endocrine disorders. The specific disorders are listed at the beginning of each section. A brief section states the normal ranges for the specific tests, and a slightly longer section discusses interpretation of the findings.     

Saliva: clinical and diagnostic usefulness. Review of the literature

Modern clinical pathology is mainly based on the analysis of blood samples, carried out through more and more sophisticated techniques. Being the blood test an invasive technique, it certainly reduces the possibility of carrying out blood analysis, especially in patients such as children, old people, handicapped people and every person who needs continuous biochemical or pharmacological monitoring. In these cases it is very important to find other body fluids that can be easily obtained and that can offer the same reliable data as blood. Due to some of its characteristics, sometime saliva may be a good alternative to venous blood, as it presents the same features of plasma or urine. The chemical analysis of saliva provides some information that are useful for metabolic, inflammatory, neoplastic and genetic diseases; furthermore radioimmunological dosages allow to assess small concentrations of active substances. On the basis of an accurate review of literature, the aim of this study is to analyse the importance of saliva in diagnosing and monitoring certain systemic diseases, the utilization of saliva in hormonal and pharmacological dosages and the use of saliva in some epidemiological studies. Finally, it is emphasized that saliva in monitoring may help to manage several clinical conditions.     

Evaluation on non invasive diagnostic tests for the second look in epithelial ovarian cancer

OBJECTIVE: To determine the usefulness of diagnostic tests performed before a second look laparotomy in patients with epithelial ovarian cancer. STUDY DESIGN: Thirty-three patients with epithelial ovarian cancer attended at Fundación Jiménez Díaz from 1984 to 1995 were studied. All patients initially underwent cyto-reducing surgery, followed by at least six platinum-based chemotherapy cycles. Prior to second look laparotomy all patients were evaluated by computerized tomography (CT) of the pelvis and abdomen, CA-125, pelvic-abdominal echography and gynecologic examination. To evaluate sensitivity, specificity, positive predictive value and negative predictive value for each test contingency tables were used. RESULTS: Eleven out of the 33 second look patients (33%) had histologic or cytologic evidence of disease. Six out of the eleven positive second look had a positive CT prior to second look (sensitivity of 55%). CT showed lack of disease in 21 out of the 22 negative second look cases (specificity 95%). Positive and negative predictive values of the test were 86% and 81%, respectively. Nine cases out of the 28 who had a CA-125 obtained had a positive second look. Four out of these nine patients had an increased CA-125 value (sensitivity 44%, specificity 95%, positive predictive value 80% and negative predictive value 78%). Sensitivity, specificity, positive predictive value and negative predictive value of physical examination and echography were 36%, 100%, 100%, 76% and 27%, 95%, 75%, 72%, respectively. On the other hand, sensitivity, specificity, positive predictive value and negative predictive value of all tests taken together were 64%, 91%, 78% and 83%, with a rate of false-negative results of 17% and a rate of false-positive results of 22%. CONCLUSION: Pelvic-abdominal computerized tomography, CA-125, pelvic-abdominal echography and gynecologic examination can be an alternative to second look laparotomy for the diagnosis of persistence or recurrence of the disease in patients with epithelial ovarian cancer.     

Newer visual function tests in the evaluation of glaucoma

Conventional visual field testing, with a uniform white-on-white stimulus, is used routinely to diagnose and follow patients with chronic open-angle glaucoma. Many investigators, however, believe that conventional perimetry may not detect the earliest visual dysfunction in patients with chronic open-angle glaucoma. Consequently, much research has been performed over the past decade to develop a visual function test which might diagnose chronic open-angle glaucoma earlier than conventional perimetry. This review discusses the mechanisms, clinical studies and the current usefulness of the most common new visual function techniques. These tests attempt to detect early glaucomatous visual loss, generally by placing the visual system under stress and by minimizing the influence of extensive functional redundancy in the retinal ganglion cell network due to widely overlapping receptive fields. Success of new visual function tests depends on the specificity and the sensitivity of the instrument, excellent patient acceptance, short test duration, standardization of techniques, and limited expense. In addition to searching for newer visual function tests to evaluate glaucoma, we should continue efforts to improve the diagnostic capability and shorten the test duration of conventional perimetry.     

Emergency diagnostic imaging in thoracic trauma. A clinical case

The authors report a case of thoracic trauma with pulmonary contusion in which chest X-ray was not significant, nevertheless severe clinical state. They underline the importance of CT in the early evaluation of pulmonary lesions and in their development.