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At least 217 records · Page 12Linked to original sources

Reproducibility of diagnostic results by a multivariate computer ECG analysis program (AVA 3.5).

Reproducibility of the AVA program (version 3.5) was tested (1) by analyzing the same analog tracing 10 times in 150 patients, and (2) by studying the influence of 12 different sets of prior probabilities (PRP), using the digital data from a total of 2718 patients. The same QRS-T diagnosis plus or minus 8 percentage points was found in patients with high posterior probabilities. Variability for the P wave diagnosis was twice as high as for QRS-T results. Failure to select the appropriate set of PrP markedly influenced reproducibility. This was especially true for right ventricular hypertrophy and pulmonary emphysema. 'Mispriorizing' in a subgroup of 199 patients with well-documented myocardial infarction lowered the total number of correct ECG diagnoses on the average between 4.8 and 35%. These results are inherent to Bayes' theorem where PrP are used to achieve minimum assignment error in populations, but where Prp errors may result in wide classification discrepancies. Without errors in PrP reproducibility by the VA program was found to be very high.

Analysis of Variance↗

Natural head position recording on frontal skull radiographs.

This paper sets out to evaluate the variability and reproducibility of frontal head position in healthy young adults. Two posteroanterior skull radiographs of 22 dental students and 2 frontal photographs of these and 24 other students, taken at a 1-week interval, were analyzed with regard to head position and cervical spine inclination. Head position varied in the range of +/- 5 degrees with regard to the vertical. The cervical spine was more often inclined to the right than to the left. The reproducibility of the head position with regard to the craniovertical angle was 1.15 degrees and that of the craniocervical and cervicohorizontal angles 0.93 degrees and 1.45 degrees, respectively. Any deviation in the frontal head position tended to be spontaneously corrected on looking in a mirror. It is concluded that the frontal head position is slightly more accurately reproducible than the sagittal head position. The use of a mirror in front of the patient when recording the frontal natural head position is not to be recommended.

Adult↗

Reproducibility of atopy patch tests with Dermatophagoides: a study on 85 patients with atopic dermatitis.

Atopy patch tests (APTs) are considered a useful addition to standard testing procedures for the identification of allergens triggering the appearance of eczema in patients with atopic dermatitis (AD). The aim of the study was to evaluate the reproducibility of APTs with house dust mites by simultaneously patch testing AD patients. 85 subjects affected by AD, 36 males and 48 females, aged from 1 to 52 years, were patch tested with Dermatophagoides mix (D. pteron/D. farinae) 20% pet. In our patients, the percentage of agreement between the frequency of positive and negative responses to Dermatophagoides mix was 96.7%. Reproducibility was highly satisfactory, as evaluated by k-value (0.953). As regards the agreement in the intensity of APT responses to Dermatophagoides mix between the right and left sides, we found that reproducibility was also highly satisfactory (k = 0.851). In conclusion, for Dermatophagoides APTs, the agreement rate was similar to that of standard patch tests, and therefore APTs may be considered sufficiently reproducible to be employed as a diagnostic testing procedure.

Adolescent↗

Reproduction memory of two-event sequences in pigeons.

Six pigeons were trained to reproduce two-event sequences in an experiment that employed a discrete-trial procedure that required subjects to peck one of four possible sample sequences (left-left, left-right, right-right, right-left) signaled on a given trial by the successive illumination of response keys. Following a retention interval (0.1 to 30 seconds), a reinforcer was delivered if a subject reproduced the prior sample sequence during a test condition in which both left and right keys were illuminated. The pigeons readily reproduced the orders in which they had just seen and pecked two illuminated keys. Reproduction accuracy declined as the retention interval was increased. Homogeneous sequences (left-left, right-right) were reproduced with greater accuracy than heterogeneous sequences.

Animals↗

Action planning during the presentation of stimulus sequences: effects of compatible and incompatible stimuli.

Experimental designs that require the simultaneous perception and reproduction of a stimulus sequence could help to clarify the relationship between perception and action. This contribution examines a specific stimulus-response compatibility with the reproduction of simple stimulus sequences. In the procedure a response just prepared or one to be prepared is confronted with a new incoming stimulus that is compatible or incompatible with the response. Interference is predicted from a framework in which stimulus perception and action control are assumed to share common codes. Five arrows were successively presented at 1-s intervals. The arrows pointed either to the left or to the right with equal probability. One of the five arrows was accompanied by a randomly presented go signal. Subjects then had to reproduce the sequence by pressing corresponding left or right keys while the stimulus presentation continued. Reaction-time latencies and reaction intervals within a sequence were analyzed in six experiments. Results showed increasing reaction-time latencies the later the go signal was presented--that is, the longer the sequence to be reproduced was. In contrast to previous findings, this effect interacted with the compatibility between the arrow displayed together with the go signal and the first reaction. It is argued that the go signal initiates a transfer of a cognitive action plan to a peripheral motor program and that this process is subject to interference the more the current stimulus is at odds with one of the first parameter specification.

Adult↗

Electrophysiologic investigation in Brugada syndrome; yield of programmed ventricular stimulation at two ventricular sites with up to three premature beats.

INTRODUCTION: Numerous reports on the inducibility of ventricular tachyarrhythmias (VT) in patients with atypical right bundle branch block and right precordial ST-elevation (Brugada syndrome) are based on multicentre studies that have used different stimulation protocols. Therefore, we prospectively investigated the inducibility of VT in these patients using a uniform protocol. METHODS: In 41 consecutive patients (29 males) showing a pattern of right bundle branch block and ST-elevation, programmed ventricular stimulation was performed in the right ventricular apex with up to three premature stimuli at sinus rhythm and at four different paced cycle lengths (500, 430, 370, and 330 ms) until refractoriness was reached or reproducible induction of a sustained (>30s) VT occurred. If a VT was not reproducibly inducible, the same protocol was repeated in the right ventricular outflow tract. RESULTS: A history of life-threatening events defined as syncope (n=17) or aborted sudden cardiac death (n=13) was present in 30 patients (73%); 11 individuals were asymptomatic. Inducibility (68%) was similar between symptomatic (n=21, 70%) and asymptomatic patients (n=7, 64%). In 16 (39%) patients, VT were reproducibly inducible. If patients were only stimulated in the right ventricular apex, inducibility rate decreased to 39%. If only two premature beats at two sites were used it was as low as 32%. The mean coupling intervals of the second and third premature stimuli inducing sustained VT were short: 189+/-21 ms vs 186+/-22 ms, respectively. Forty-four percent of all patients (i.e. 64% of the inducible patients) had inducible VT only with coupling intervals shorter than 200 ms. CONCLUSIONS: The stimulation protocol markedly influences the extent of inducibility of VT in patients with right bundle branch block and ST-segment elevation. These findings question the significance of previous multicentre studies using different stimulation protocols and should have implications for further studies.

Adult↗

Reproducibility study of 3D geometrical reconstruction of the human carotid bifurcation from magnetic resonance images.

The combined magnetic resonance imaging (MRI) and computational fluid dynamics (CFD) modeling approach is playing an increasingly important role in advancing our understanding of the relationship between hemodynamics and arterial disease. Nevertheless, such a modeling approach involves a number of uncertainties associated with various stages of the process. The present study is concerned with the reproducibility of geometry reconstruction, one of the most crucial steps in the modeling process. The reproducibility test was conducted on the right carotid bifurcation of eight normal human subjects, each of whom were scanned twice using the same MR protocol with an in-plane resolution of 0.625 mm. Models constructed from different scans of the same subject were compared and assessed using four quantitative measures: centerline distance, cross-sectional area, contour shape factors, and mean radius difference. The difference in the maximum carotid bulb area between the two scans was found to be <8.1% for all subjects. Shape factors (measuring the dissimilarity between two contours) of <10% were achieved in most of the common carotid arteries (CCAs) and internal carotid arteries (ICAs). The mean radius difference between the two scans was <0.4 mm for all subjects. Among the three vessels, the geometry of CCA was well reproduced by the reconstruction procedure in most of the cases, while the external carotid artery (ECA) showed the worst reproducibility. The impact of geometrical differences on CFD-predicted flow patterns and wall shear stress (WSS) will be investigated and discussed in a separate paper.

Adult↗

Laparoscopic appendectomy using a clip applier.

The diagnostic worth and therapeutic value of laparoscopic surgery are known for ovarian cysts and ectopic pregnancies. Diagnosis of appendicitis is difficult, and laparoscopy is useful in these cases. The present study was done to assess the feasibility, efficacy, and advantages of a new laparoscopic appendectomy technique. Between August 1, 1989, and July 31, 1990, patients exhibiting right pelvic pain associated with fever were divided into three groups according to the pre-operative diagnosis: appendicitis, pelvic inflammatory disease (PID), and diagnostic doubt between appendicitis and PID. An intra-peritoneal appendectomy was performed if the diagnosis was not PID. Via three suprasymphyseal trocars, the appendix was exposed and the mesoappendix was coagulated. The appendix stump was closed using a clip applier (Ethnor T1300). In all, 20 patients underwent laparoscopic appendectomies. The mean duration of the procedure was 36.5 min; in no case was laparotomy necessary. There were no post-operative complications, and digestive transit returned on the 2nd day post-surgery. Both patients and nurses appreciated the technique. The subjects experienced comfortable post-operative periods and gained aesthetic advantages. The operative procedure could be completed on each attempt. We conclude that this technique is sure, quick, and easily reproducible in young patients presenting with right pelvic pain associated with fever.

Appendectomy↗

Experimental osteomyelitis: what have we learned from animal studies about the systemic treatment of osteomyelitis?

Clinical trials of systemic antibiotic treatment of osteomyelitis are difficult to perform for many reasons, such as low incidence rate of osteomyelitis, variety of anatomic locations, stage and etiologic agents. In this article, we reviewed the experimental studies on osteomyelitis available in the English medical literature since 1968, to ascertain their actual and potential impact on the treatment of human osteomyelitis. Major results are summarized and topics of major interest, such as reproducibility of animal models, predictive value of animal models, correlation of pharmacokinetics between different animals and humans, and the correlation of outcome between animal and clinical studies are discussed. Most of the reviewed animal models are reproducible and dependable. However, establishing the right dose regimen in animals appeared a critical factor, which might undermine the predictive value of the experimental study. Due to difficulties in comparing results of animal and human studies, the predictive value of animal studies about osteomyelitis is still unclear. However, animal models gave valuable information to the clinician for choosing the minimal duration of antibiotic treatment. Even though the use of antibiotic combinations was associated with better outcome in the majority of animal studies, such a finding seems to have limited impact on clinical practice.

Animals↗

Evaluation of right and left ventricular function by quantitative blood-pool SPECT (QBS): comparison with conventional methods and quantitative gated SPECT (QGS).

Though quantitative ECG-gated blood-pool SPECT (QBS) has become a popular tool in research settings, more verification is necessary for its utilization in clinical medicine. To evaluate the reliability of the measurements of left and right ventricular functions with QBS, we performed QBS, as well as first-pass pool (FPP) and ECG-gated blood-pool (GBP) studies on planar images in 41 patients and 8 healthy volunteers. Quantitative ECG-gated myocardial perfusion SPECT (QGS) was also performed in 30 of 49 subjects. First, we assessed the reproducibility of the measurements of left and right ventricular ejection fraction (LVEF, RVEF) and left and right ventricular end-diastolic volume (LVEDV, RVEDV) with QBS. Second, LVEF and RVEF obtained from QBS were compared with those from FPP and GBP, respectively. Third, LVEF and LVEDV obtained from QBS were compared with those from QGS, respectively. The intra- and inter-observer reproducibilities were excellent for LVEF, LVEDV, RVEF and RVEDV measured with QBS (r = 0.88 to 0.96, p < 0.01), while the biases in the measurements of RVEF and RVEDV were relatively large. LVEF obtained from QBS correlated significantly with those from FPP and GBP, while RVEF from QBS did not. LVEF and LVEDV obtained from QBS were significantly correlated with those from QGS, but the regression lines were not close to the lines of identity. In conclusion, the measurements of LVEF and LVEDV with QBS have good reproducibility and are useful clinically, while those of RVEF and RVEDV are less useful compared with LVEF and LVEDV. The algorithm of QBS for the measurements of RVEF and RVEDV remains to be improved.

Adult↗

The impact of right atrial ischemia on inferior myocardial infarction with extension to right ventricle: transesophageal echocardiographic examination.

BACKGROUND: The role of the right atrium in adaptation to the hemodynamic changes produced by extension of myocardial infarction (MI) of the left ventricular inferior wall to the right ventricle is fundamental. HYPOTHESIS: The aim of this study was analyze a group of patients with MI with extension of right chambers, and particularly right atrial alterations, by transesophageal echocardiography and to correlate it with clinical and angiographic variables. METHODS: Thirty patients with right ventricular (RV) MI involving obstruction of the right coronary artery without stenosis of the left coronary artery were included; 18 underwent early reperfusion. Transesophageal echocardiography was performed on all within 5 days of coronary angiography. Follow-up was continued from hospitalization to the present. RESULTS: When patients with right atrial ischemia were compared with those with normal right atrium, the RV wall movement score was significantly greater in the group with right atrial ischemia, severe RV dilatation was more frequent, and association with proximal occlusion of the artery responsible for the MI, as well as absence of right atrial branches and poor collateral circulation, were significant. Hospitalization was more prolonged in this group, and there was a higher incidence of arrhythmias, complete atrioventricular block, and mortality. CONCLUSIONS: Right atrial ischemia associated with RV infarction leads to a higher incidence of complications and higher mortality. Transesophageal echocardiography is a safe, reproducible technique that provides detailed anatomic information about right chambers and aids in the determination of prognosis and therapeutic decisions.

Adult↗

Isolated mouse atrium as a model to study anthracycline cardiotoxicity: the role of the beta-adrenoceptor system and reactive oxygen species.

Cancer chemotherapy with anthracyclines, of which doxorubicin (DX2) is the main representative, is limited by cardiomyopathy developing in animals and patients after cumulative dosing. The toxicity is probably related to free radical formation by the anthracycline as well as its metabolites with concomitant O2.- and .OH generation resulting in lipid peroxidation and subsequent membrane damage. An in vitro model is required to investigate the individual contribution of each metabolite to cardiotoxicity. For in vivo studies, the species of choice is the mouse because it lacks the DX-induced nephrotic syndrome seen for instance in rats and rabbits. Thus, isolated mouse heart muscle was chosen as an in vitro model. To characterize the model, we used l-isoprenaline/dl-propranolol and metacholine/atropine to measure the beta-adrenergic and the muscarinic responses of (spontaneously beating) right and (paced) left atrium. Dose response curves (n greater than or equal to 4) were highly reproducible: pD2,iso = 8.0 +/- 0.3 (left) and 8.5 +/- 0.4 (right); pD2,met = 6.7 +/- 0.1 (left) and 6.2 +/- 0.3 (right). Propranolol as well as atropine behaved as competitive antagonists, with pA2-values of 8.4 +/- 0.2/8.5 +/- 0.2 (l/r) and 9.1 +/- 0.1/9.1 +/- 0.2 (l/r), respectively. These values corresponded to those obtained with other organ preparations. We tested the effect of DX in two ways: a) by measuring the direct inotropic and chronotropic effect during 60 minutes of incubation with 10-100 microM DX in the organ bath, and b) by determining the remaining beta-adrenergic response to l-isoprenaline after the incubation period. Both variables turned out to be equally affected. For paced left atria an IC50 (causing 50% depression of contractile force) of 35 microM was determined. Right atria stopped beating at concentrations above 50 microM, thus hampering IC50 determination. The results indicate that anthracyclines exert an effect not related to receptor integrity, but directly to the functionality of heart muscle. To check whether radical stress can be involved in the observed negative inotropic effect, incubations with xanthine/xanthine oxidase (to produce reactive oxygen species) were performed. A pronounced negative effect on mouse atrial contraction was indeed observed. However, initially a positive inotropic effect accompanied by an increased resting tension were seen. It can be concluded that mouse atrium can be used as a model to compare anthracyclines and their metabolites with regard to their acute cardiotoxic effects.

Animals↗

Reproducibility and variation of skin surface temperature over the temporomandibular joint and masseter muscle in normal individuals.

Temperature, temperature differences between right and left sides, temperature variation with time, and temperature measurement reproducibility were investigated in 42 normal individuals over the origin of the superficial portion of the masseter muscle and the temporomandibular joint (TMJ) with fast- and slow-reacting thermistors. The average temperature was higher with the fast-reacting thermistor than with the slow-reacting thermistor for all measured locations. The temperature difference between the left and right side was in about 90% of the performed measurements less than or equal to 1 degree C in both locations. The temperature also differed between the two locations and was highest at the skin surface over the TMJ. The reproducibility of the method according to the standard deviation of a single measurement was satisfactory.

Adult↗

Effects of normobaric hyperoxia on hemodynamics and O2 utilization in conscious dogs.

Normobaric hyperoxia decreased resting whole-body O2 consumption in conscious dogs by equal (Fick) contributions from decreases in cardiac output and in the arterial-venous difference in O2 content. The decrease in O2 consumption was fully developed by 20 min, was maintained for at least 1 h, and was both reversible and reproducible. Hyperoxia also decreased heart rate, right and left ventricular work rates (and therefore, presumably myocardial O2 consumption), and pulmonary vascular resistance; and increased systemic vascular resistance and right atrial pressure. Paradoxically, hyperoxia did not change O2 delivery. This latter observation together with the decrease in O2 consumption produced a unique vertical orientation to the O2 consumption-delivery relationship induced by hyperoxia. It is concluded that hyperoxia may decrease metabolic rate and substantially alter hemodynamics, which may have important implications for understanding the metabolic regulation of oxygen utilization and for the medical and nonmedical uses of oxygen.

Animals↗

Laparoscopic right colectomy: five-step procedure.

The advanced laparoscopic skills required for laparoscopic resection of the colon and rectum have precluded wide dissemination of this procedure. By applying certain key principles, laparoscopic right hemicolectomy can be made simple, reproducible, easy to teach, easy to learn, and cost-effective.

Colectomy↗

[Unilateral auditory neuropathy. A rare differential diagnosis of unilateral deafness].

Auditory neuropathy presents with normal otoacoustic emissions combined with pathological findings in brainstem evoked response audiometry. Normally, the auditory neuropathy is bilateral. We report about a 9 year old child where we could diagnose a unilateral deafness in spite of regular TEOAE and DPOAE. No reproducible biosignals were seen when the right ear was stimulated with alternating click stimuli at a level of 80 dB. On the left side, the latency of the potentials was normal. A cranial MRI showed normal anatomy. In order to determine a unilateral deafness, objective tests (e.g., OAE, BERA) and subjective tests should be used.

Auditory Diseases, Central↗

Analysis of the anatomic changes in the thoracic cage after a lung resection using magnetic resonance imaging.

The thoracic cage after a lung resection is filled by the remaining lobes, the elevated diaphragm, the diminished thoracic cage, and by mediastinal shifting. The changes in the thorax after a lung resection were quantified using magnetic resonance imaging. The study group consisted of 39 patients who had undergone a lobectomy, four who had undergone a pneumonectomy, and 14 controls. The left ventricular angle, ascending aortic angle, mediastinal shift, longitudinal length of the thoracic cage, the distance between the thoracic apex and the level of the aortic valve, and diaphragmatic elevation were all measured. After a right lower lobectomy, the mediastinum shifted more rightward than after a right upper lobectomy. The diaphragm became more greatly elevated after a right upper lobectomy than after a right lower lobectomy. When a chest wall resection was added to a right upper lobectomy, the mediastinal anatomical changes decreased. After a left upper lobectomy, the degree of mediastinal shifting was greater than after a left lower lobectomy. A left upper lobectomy shifted the mediastinum at the level of the right atrium. This method is easily reproducible and was found to be effective for quantifying the changes in the thorax after a lung resection.

Case-Control Studies↗

In vivo experiments for the evaluation of alpha 1-adrenoceptor antagonistic effects of SGB-1534 on canine urethra.

The alpha 1-adrenoceptor blocking effects of SGB-1534 on the urethral smooth muscle were compared in in vivo lower urinary tract preparations of anesthetized dogs, with the effects of other alpha 1-adrenoceptor antagonists, prazosin and bunazosin. Hypogastric nerve stimulation and selective administration of phenylephrine to the urethra and bladder through the cannulated right external iliac artery (i.a.) elicited reproducible frequency- and dose-dependent increases in intra-urethral pressure. Intra-bladder pressure was increased by the nerve stimulation but not by i.a. phenylephrine. SGB-1534, prazosin or bunazosin (0.1-10 micrograms/kg i.v.) dose dependently suppressed the urethral contraction evoked by the nerve stimulation and i.a. phenylephrine but did not influence the bladder contraction elicited by nerve stimulation. The alpha 1-adrenoceptor blocking potency of SGB-1534 was approximately 2.3 and 8.1 times greater than that of prazosin and bunazosin, respectively. The results indicate that alpha 1-adrenoceptors may mediate mainly the urethral contraction induced by hypogastric nerve stimulation and i.a. phenylephrine, and that SGB-1534 was more potent alpha 1-adrenoceptor blocking activity than prazosin and bunazosin in the canine urethra.

Adrenergic alpha-Antagonists↗