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Healthy Subjects (healthy + subject)
Kinds of Healthy Subjects Selected AbstractsCircadian Profile of Cardiac Autonomic Nervous Modulation in Healthy Subjects:JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 8 2003Differing Effects of Aging, Gender on Heart Rate Variability Introduction: Although heart rate variability (HRV) has been established as a tool to study cardiac autonomic activity, almost no data are available on the circadian patterns of HRV in healthy subjects aged 20 to 70 years. Methods and Results: We investigated 166 healthy volunteers (81 women and 85 men; age 42 ± 15 years, range 20,70) without evidence of cardiac disease. Time-domain HRV parameters were determined from 24-hour Holter monitoring and calculated as hourly mean values and mean 24-hour values. All volunteers were fully mobile, awoke around 7 A.M., and had 6 to 8 hours of sleep. Circadian profiles of vagus-associated HRV parameters revealed a marked day-night pattern, with a peak at nighttime and a plateau at daytime. The characteristic nocturnal peak and the day-night amplitude diminished with aging by decade. Estimates of overall HRV (geometric triangular index [TI], SD of NN intervals [SDNN]) and long-term components of HRV (SD of the averages of NN intervals for all 5-min segments [SDANN]) were low at nighttime and increased in the morning hours. There was a significant decline of 24-hour values of all HRV parameters (P < 0.001) and a strong negative correlation (P < 0.001) with increasing age. Mean 24-hour RR interval (P < 0.001), SDNN, mean SD of NN intervals for all 5-minute intervals (SDNNi), and SDANN (all P < 0.01) were significantly higher in men. Younger men also exhibited significantly higher values for vagus-associated parameters (root mean square successive difference [rMSSD], P < 0.05; SDNNi, P < 0.01); however, gender differences diminished with increasing age. Conclusion: Normal aging is associated with a constant decline of cardiac vagal modulation due to a significant decrease of nocturnal parasympathetic activity. The significant gender-related difference of HRV decreases with aging. These findings emphasize the need to determine age-, gender-, and nycthemeral-dependent normal ranges for HRV assessment. (J Cardiovasc Electrophysiol, Vol. 14, pp. 791-799, August 2003) [source] Acute Effects of Low Doses of Red Wine on Cardiac Conduction and Repolarization in Young Healthy SubjectsALCOHOLISM, Issue 12 2009Matteo Cameli Background:, Moderate to high blood concentrations of ethanol have been shown to yield acute changes in cardiac electrophysiological properties, but the effect of low concentrations have never been assessed. The role of concomitant changes in clinical variables or cardiac dimensions is also still unknown. This study aimed at exploring the acute effects of low doses of ethanol, administered as Italian red wine, on conduction, depolarization, and repolarization electrocardiographic (ECG) intervals in a population of healthy subjects. Methods:, Forty healthy young volunteers drank a low quantity of red wine (5 ml/kg), and an equal volume of fruit juice in separate experiments. Heart rate, P-wave duration, PR interval, QRS duration, QT interval, corrected QT interval, QT dispersion, and corrected QT dispersion were assessed at baseline and after 60 minutes from challenge. Results:, Mean blood ethanol concentration after drinking was 0.48 ± 0.06 g/l. Compared to the control challenge, significant changes after red wine intake were observed in P-wave duration (from 101 ± 11 to 108 ± 14 milliseconds, p = 0.0006), PR interval (from 153 ± 15 to 167 ± 17 milliseconds, p < 0.0001), QT interval (from 346 ± 28 to 361 ± 24 milliseconds, p < 0.0001), and corrected QT interval (from 388 ± 24 to 402 ± 30 milliseconds, p = 0.0006). None of these changes showed correlations with modifications in clinical or echocardiographic variables. In multivariate analyses aimed at exploring predictors of ECG changes, none of the variables entered the final models. Conclusions:, Low doses of red wine acutely slow cardiac conduction and prolong repolarization in normal individuals. These changes are poorly predictable. The potential arrhythmogenic impact of these effects is worthy of exploration. [source] Effects of Alcohol on Polysomnographically Recorded Sleep in Healthy SubjectsALCOHOLISM, Issue 9 2006Bernd Feige Background: After studying the sleep of alcohol-dependent patients at the beginning and over the course of abstinence in earlier studies, our interest in the current study focused on the direct effect of 2 doses of alcohol [0.03 and 0.1% blood alcohol level (BAL)] on healthy sleep. This is the first polysomnographic study testing the impact of 2 doses of alcohol ingestion (thus reflecting "normal" social drinking and alcohol abuse) in a single-blind randomized design in healthy volunteers. The study evaluated a short-term acute drinking period for 3 and 2 days of withdrawal from alcohol not only for polysomnographic variables but also for subjective estimates of sleep quality. Methods: In a crossover design with a 1-week interval, healthy subjects received alcohol to raise their blood alcohol to either 0.03 or 0.1% BAL at bedtime for 3 consecutive nights after an alcohol-free baseline night. Objective (polysomnography) and subjective sleep (questionnaires) was recorded each night. During the following 2 days, alcohol was discontinued with simultaneous measurements of sleep to gauge withdrawal effects. Results: At a dose of alcohol leading to BAL of 0.03%, no clear effects could be detected. Following an evening BAL of 0.1%, a hypnotic-like effect (shortened sleep latency, reduced number of wake periods, decreased stage 1 sleep) occurred primarily during the first half of the night with signs of rebound effects being already present during the second half of the night (increased stage 1 sleep). At this dose, alcohol significantly increased slow-wave sleep (SWS) in the first half of the night and reduced REM density in the beginning of the night. After discontinuation of the higher alcohol dose, REM sleep amount increased. No significant withdrawal or rebound effects could be observed for parameters of sleep continuity during the 2 nights after discontinuation from alcohol at a BAL of 0.1%. Conclusions: Owing to the small sample size, the results of this study need to be interpreted with caution. Short-term moderate alcohol consumption (BAL 0.03%) did not significantly alter objective or subjective parameters of sleep. Higher doses of alcohol resulting in a BAL level of 0.10% immediately before going to bed mainly influenced sleep in the first half of the night, resembling the effects of a short-acting hypnotic drug, including a suppression of phasic aspects of REM sleep (REM density). Interestingly, analysis of the latter part of these nights indicated the immediate presence of withdrawal effects (increased light sleep). No statistically significant effects on sleep parameters were observable during the 2 nights of withdrawal from alcohol at the higher BAL. Interpreted carefully, our data indicate that negative effects on sleep occur already with short-term use of alcohol at doses of BAL of 0.10%, despite hypnotic-like effects during the first hours of sleep, especially during the latter part of the night. [source] The Time Course of New T-Wave ECG Descriptors Following Single- and Double-Dose Administration of Sotalol in Healthy SubjectsANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 1 2010Fabrice Extramiana M.D., Ph.D. Introduction: The aim of the study was to assess the time course effect of IKr blockade on ECG biomarkers of ventricular repolarization and to evaluate the accuracy of a fully automatic approach for QT duration evaluation. Methods: Twelve-lead digital ECG Holter was recorded in 38 healthy subjects (27 males, mean age = 27.4 ± 8.0 years) on baseline conditions (day 0) and after administration of 160 mg (day 1) and 320 mg (day 2) of d-l sotalol. For each 24-hour period and each subject, ECGs were extracted every 10 minutes during the 4-hour period following drug dosage. Ventricular repolarization was characterized using three biomarker categories: conventional ECG time intervals, principal component analysis (PCA) analysis on the T wave, and fully automatic biomarkers computed from a mathematical model of the T wave. Results: QT interval was significantly prolonged starting 1 hour 20 minutes after drug dosing with 160 mg and 1 hour 10 minutes after drug dosing with 320 mg. PCA ventricular repolarization parameters sotalol-induced changes were delayed (>3 hours). After sotalol dosing, the early phase of the T wave changed earlier than the late phase prolongation. Globally, the modeled surrogate QT paralleled manual QT changes. The duration of manual QT and automatic surrogate QT were strongly correlated (R2= 0.92, P < 0.001). The Bland and Altman plot revealed a nonstationary systematic bias (bias = 26.5 ms ± 1.96*SD = 16 ms). Conclusions: Changes in different ECG biomarkers of ventricular repolarization display different kinetics after administration of a potent potassium channel blocker. These differences need to be taken into account when designing ventricular repolarization ECG studies. Ann Noninvasive Electrocardiol 2010;15(1):26,35 [source] Comparison of Quantitative T-Wave Alternans Profiles of Healthy Subjects and ICD PatientsANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 2 2009B.Eng., Euler De Vilhena Garcia Ph.D., M.Sc. Background: Current relevance of T-wave alternans is based on its association with electrical disorder and elevated cardiac risk. Quantitative reports would improve understanding on TWA augmentation mechanisms during mental stress or prior to tachyarrhythmias. However, little information is available about quantitative TWA values in clinical populations. This study aims to create and compare TWA profiles of healthy subjects and ICD patients, evaluated on treadmill stress protocols. Methods: Apparently healthy subjects, not in use of any medication were recruited. All eligible ICD patients were capable of performing an attenuated stress test. TWA analysis was performed during a 15-lead treadmill test. The derived comparative profile consisted of TWA amplitude and its associated heart rate, at rest (baseline) and at peak TWA value. Chi-square or Mann-Whitney tests were used with p values , 0.05. Discriminatory performance was evaluated by a binary logistic regression model. Results: 31 healthy subjects (8F, 23M) and 32 ICD patients (10F, 22M) were different on baseline TWA (1 ± 2 ,V; 8 ± 9 ,V; p < 0.001) and peak TWA values (26 ± 13 ,V; 37 ± 20 ,V; p = 0,009) as well as on baseline TWA heart rate (79 ± 10 bpm; 67 ± 15 bpm; p < 0.001) and peak TWA heart rate (118 ± 8 bpm; 90 ± 17 bpm; p < 0.001). The logistic model yielded sensitivity and specificity values of 88.9% and 92.9%, respectively. Conclusions: Healthy subjects and ICD patients have distinct TWA profiles. The new TWA profile representation (in amplitude-heart rate pairs) may help comparison among different research protocols. [source] Electrocardiographic Alterations during Hyperinsulinemic Hypoglycemia in Healthy SubjectsANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 2 2008Tomi Laitinen M.D. Background: We evaluated the arrhythmogenic potential of hypoglycemia by studying electrocardiographic (ECG) changes in response to hyperinsulinemic hypoglycemia and associated sympathoadrenal counterregulatory responses in healthy subjects. Methods: The study population consisted of 18 subjects, aged 30,40 years. Five-minute ECG recordings and blood samplings were performed at baseline and during the euglycemic and hypoglycemic hyperinsulinemic clamp studies. PR, QT, and QTc intervals of electrocardiogram and ECG morphology were assessed from signal-averaged ECG. Results: Although cardiac beat interval remained unchanged, PR interval decreased (P < 0.01) and QTc interval (P < 0.001) increased in response to hyperinsulinemic hypoglycemia. Concomitant morphological alterations consisted of slight increases in R-wave amplitude and area (P < 0.01 for both), significant decreases in T-wave amplitude and area (P < 0.001 for both), and moderate ST depression (P < 0.001). Counterregulatory norepinephrine response correlated with amplification of the R wave (r =,0.620, P < 0.05) and epinephrine response correlated with flattening of the T wave (r =,0.508, P < 0.05). Conclusions: Hyperinsulinemic hypoglycemia with consequent sympathetic humoral activation is associated with several ECG alterations in atrioventricular conduction, ventricular depolarization, and ventricular repolarization. Such alterations in cardiac electrical function may be of importance in provoking severe arrhythmias and "dead-in-bed" syndrome in diabetic patients with unrecognized hypoglycemic episodes. [source] Circadian Variation in QT Dispersion Determined from a 12-Lead Holter Recording: A Methodological Study of an Age- and Sex-Stratified Group of Healthy SubjectsANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 3 2007Stig Hansen M.D. Background: QT dispersion is considered to reflect inhomogeneity of myocardial repolarization. Method: The circadian variation of QT interval dispersion was examined in 95 healthy subjects using 24-hour Holter monitoring. Three different methods of lead selection were applied: all 12 leads (QTdisp 12), only precordial leads (QTdisp 6), and the pair of leads selected at 3 a.m. in which the longest and shortest QT intervals were found in each individual subject (QTdisp 2). Results: A preliminary methodological study including measurements from every minute in 10 subjects revealed no significant circadian variation using mean values of QTdisp 12, QTdisp 6, or QTdisp 2 obtained every hour, every 2, or every 4 hours, except in QTdisp 6, which demonstrated a significant circadian variation (P < 0.01) in 1-hour measurements. Analysis of all 95 subjects using measurements obtained every 4 hours revealed a significant circadian variation in QTdisp 12 and QTdisp 6 (P < 0.0001), whereas no circadian variation was seen in QTdisp 2. A subdivision into 10-year age groups revealed that subjects at age >50 years had a significant circadian variation in QTdisp 12 and QTdisp 6, but not in QTdisp 2. Only in males a significant circadian variation was seen in QTdisp 12 (P < 0.0001), whereas QTdisp 6 demonstrated a circadian variation both in females (P < 0.001) and in males (P < 0.0001). Conclusions: Selection of leads is of crucial importance for repetitive measurements of QT dispersion. Circadian variation was detected in subjects over 50 years of age, when all 12 or only the 6 precordial leads were taken into account. [source] Dynamics of Ventricular Repolarization in Patients with Dilated Cardiomyopathy Versus Healthy SubjectsANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 2 2005Jose Luis Alonso M.D. Background: Patients with impaired left ventricular function have a high risk of developing ventricular arrhythmias and sudden death. Among different markers of risk, the prolongation and regional heterogeneity of repolarization are of increasing interest. However, there are limited data regarding feasibility of analyzing repolarization parameters and their dynamics in 24-hour Holter ECG recordings. Methods: Dynamic behavior of repolarization parameters was studied with a new automatic algorithm in digital 24-hour Holter recordings of 60 healthy subjects and 55 patients with idiopathic dilated cardiomyopathy (IDC). Repolarization parameters included the mean value of QT and QTc durations, QT dispersion, and peaks of QT duration and QT dispersion above prespecified thresholds. Results: In comparison to healthy subjects, patients with IDC had lower heart rate variability, longer mean QT and QTc durations, higher content of QTc peaks >500 ms, longer QT dispersion and its standard deviation, and a higher content of peaks >100 ms of QT dispersion (P < 0.01 for all comparisons). These repolarization parameters were significantly higher in IDC patients after adjustment for age, sex, and heart rate variability. The parameters of repolarization dynamics correlated with SDNN in healthy subjects but not in dilated cardiomyopathy patients. Conclusions: The automatic assessment of repolarization parameters in 24-hour digital ECG recordings is feasible and differentiates dilated cardiomyopathy patients from healthy subjects. Patients with dilated cardiomyopathy have increased QT duration, QT dispersion, and increased variability of QT dispersion reflecting variations in T-wave morphology, the factors which might predispose them to the development of arrhythmic events. [source] Beat-to-Beat QT Dynamics in Healthy SubjectsANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 1 2004Berit T. Jensen M.D. Background: Measures of QT dynamics express repolarization abnormalities that carry prognostic information, but the reproducibility of beat-to-beat QT dynamics has never been established. The QT interval is prolonged at night, but how the circadian rhythm and heart rate influence the dynamic QT measurements is still unsettled. The aims of the present study were: (1) to describe the reproducibility of beat-to-beat QT dynamics with respect to intrasubject, between-subject, and between-observer variability and (2) to describe the normal range, circadian variation, and heart rate dependence of QT dynamics. Methods: Ambulatory Holter recordings were performed three times on 20 healthy volunteers and were analyzed by two experienced cardiologists. Slope and intercept of the QT/RR regression, the variability of QT and R-R intervals expressed as the standard deviation, and the relation between QT and RR variability expressed as a variability ratio were measured among other QT dynamics. Results: The reproducibility of all QT dynamics was good. All QT dynamics showed circadian variation when calculated on an hourly basis. The day/night variation in slope could be explained by the differences in heart rate, whereas the day/night variation in intercept was heart rate independent. Conclusion: The present study shows that reliable automatic QT measurements could be performed, encouraging further evaluation of the clinical value of QT dynamics in risk stratification of cardiac patients. [source] Pharmacokinetic Interaction of the Direct Renin Inhibitor Aliskiren with Furosemide and Extended-Release Isosorbide-5-Mononitrate in Healthy SubjectsCARDIOVASCULAR THERAPEUTICS, Issue 4 2008Sujata Vaidyanathan This study investigated the pharmacokinetics, safety, and tolerability of aliskiren administered alone or in combination with either the loop diuretic furosemide or an oral extended-release formulation of isosorbide-5-mononitrate (ISMN). In separate studies, 22 healthy subjects (ages 18,45 years) received either ISMN 40 mg or furosemide 20 mg once-daily for 3 days followed by a 3-day washout. Subjects then received aliskiren 300 mg once-daily for 7 days followed by combination therapy for 3 days. Pharmacokinetic assessments were taken at regular intervals over 24 h after dosing on the last day of each treatment period. At steady state, aliskiren AUC, was decreased by 7% (geometric mean ratio [90% CI], 0.93 [0.84, 1.04]), and Cmax by 20% (0.80 [0.65, 0.97]) with furosemide coadministration compared with aliskiren administration alone. Aliskiren coadministration reduced furosemide AUC, by 28% (0.72 [0.64, 0.81]) and Cmax by 49% (0.51 [0.39, 0.66]) compared with furosemide alone. Coadministration of aliskiren and ISMN was associated with only minor changes in the pharmacokinetic parameters of aliskiren (AUC, 1.03 [0.90, 1.18]; Cmax 0.94 [0.69, 1.29]) and ISMN (AUC, 0.88 [0.71, 1.10]; Cmax 0.94 [0.79, 1.13]). Headache and dizziness were the most common adverse events in both studies; dizziness and BP values below normal (SBP <90 and/or DBP <50 mmHg) were more frequent with aliskiren and ISMN coadministration than with either agent alone. Coadministration of aliskiren and ISMN had no clinically relevant effect on either aliskiren or ISMN pharmacokinetics. In conclusion, coadministration of aliskiren and furosemide reduced furosemide exposure and had a minor effect on aliskiren pharmacokinetics. The clinical significance of reduced systemic exposure to furosemide during coadministration of aliskiren is uncertain. [source] Concentration Of Egg White Lysozyme In The Serum Of Healthy Subjects After Oral AdministrationCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 1-2 2002Seiichi Hashida SUMMARY 1. While the egg white lysozyme preparation ER0068 (Neuzym®; Eisai, Tokyo, Japan) is widely used clinically, no studies have been performed on its pharmacokinetic properties at clinically relevant doses. In the present study, we used a highly sensitive two-site enzyme immunoassay in order to determine the pharmacokinetic properties of egg white lysozyme after oral administration of two doses within the clinical range, paying particular attention to the effects of food intake. 2. A total of 22 healthy male subjects aged 20,45 years participated in the study. All subjects had been screened for egg white allergy and non-specific lysozyme inhibitors in their serum. Subjects who received 90 mg ER0068 after an overnight fast reached a maximum serum concentration of 1700 pg/mL within 1 h, compared with non-detectable levels in untreated controls. In a second experiment, subjects received 30 and 90 mg ER0068 after an overnight fast and 90 mg in the non-fasted state and exhibited maximum serum levels of 37, 360 and 49 pg/mL, respectively. Egg white lysozyme concentrations in serum returned to undetectable levels after a maximum of 48 h. 3. We conclude that clinically relevant concentrations of egg white lysozyme are absorbed in significant amounts, despite its high molecular weight. However, food intake considerably reduces the amount of enzyme absorbed. [source] Corrective movements in response to displacements in visual feedback are more effective during periods of 13,35 Hz oscillatory synchrony in the human corticospinal systemEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2006Alexandros G. Androulidakis Abstract Oscillatory synchronization in the beta (,20 Hz) band is a common feature of human motor control, manifest at cortical and muscular levels during tonic contraction. Here we test the hypothesis that the influence of visual feedback on performance in a positional hold task is increased during bursts of beta-band synchrony in the corticospinal motor system. Healthy subjects were instructed to extend their forefinger while receiving high-gain visual feedback of finger position on a PC screen. Small step displacements of the feedback signal were triggered either by bursts of beta oscillations in scalp electroencephalogram or randomly with respect to cortical beta activity, and the resulting positional corrections expressed as a percentage of the step displacement. Corrective responses to beta and randomly triggered step changes in visual feedback were 41.7 ± 4.9 and 31.5 ± 6.8%, respectively (P < 0.05). A marked increase in the coherence in the beta band was also found between muscle activity and cortical activity during the beta-triggered condition. The results suggest that phasic elevations of beta activity in the corticospinal motor system are associated with an increase in the gain of the motor response to visual feedback during a tonic hold task. Beta activity may index a motor state in which processing relevant to the control of positional hold tasks is promoted, with behavioural consequences. [source] Is there a greater mandibular movement capacity towards the left?JOURNAL OF ORAL REHABILITATION, Issue 4 2005Verification of an observation from 192 summary, In 1921, the German dentist Hans Wertheim reported that more individuals were able to shift the mandible more towards the left than to the right. This study analyses the deviation from symmetrical mobility of the lower jaw in either direction. Using a millimetre ruler, maximum jaw opening (MJO), maximum left laterotrusion (MLL), and maximum right laterotrusion (MRL) were recorded in 141 healthy individuals and in 141 patients with temporomandibular disorders (TMDs). For both sexes, the mean maximum movements to the left and to the right were greater in the healthy group as compared with the TMD group. Healthy subjects as well as patients were able to move the mandible more to one side. Only a minority had identical values for MLL and MRL. The majority of healthy individuals and TMD patients could move more to the left (P < 0·001). In the healthy group, the mean ratio between MJO and MLL was 5·0, and 5·5 between MJO and MRL. In the TMD group, the corresponding values were 4·6 and 6.1. The mean absolute difference between MLL and MLR (in mm) was 1·24 [95% confidence interval (CI): 0·99; 1·49] among healthy females, and 2·09 (95% CI: 1·52; 2·66) among healthy males. In the TMD group, the corresponding values were 2·62 (95% CI: 2·21; 3·04) and 2·83 (95% CI: 1·67; 4·00), respectively. From the results of our study we conclude that moderate deviations from symmetric movements (mean: 1·2 mm for women, 2·1 mm for men) appear to be the norm even in healthy individuals. [source] Methodology of oral sensory testsJOURNAL OF ORAL REHABILITATION, Issue 8 2002R. Jacobs Summary Different methods of oral sensory tests including light touch sensation, two-point discrimination, vibrotactile function and thermal sensation were compared. Healthy subjects were tested to assess the results obtained from two psychophysical approaches, namely the staircase and the ascending & descending method of limits for light touch sensation and two-point discrimination. Both methods appeared to be reliable for examining oral sensory function. The effect of topical anaesthesia was also evaluated but no conclusion could be drawn as too few subjects were involved. Newly developed simple testing tools for two-point discrimination and thermal sensation in a clinical situation were developed prior to this study and tested for their reproducibility. Thermal sensation could be reliably detected in repeated trials. Although the hand-held instruments have some drawbacks, the outcome of these instruments in a clinical environment is suitable for assessing oral sensory function. Three different frequencies (32, 128 and 256 Hz) were used to estimate the vibrotactile function. Different threshold levels were found at different frequencies. [source] Modulatory effects of low- and high-frequency repetitive transcranial magnetic stimulation on visual cortex of healthy subjects undergoing light deprivationTHE JOURNAL OF PHYSIOLOGY, Issue 2 2005Brigida Fierro The aim of the present study was to explore further the effects of light deprivation (LD) on visual cortex excitability. Healthy subjects reporting reliable induction of phosphenes by occipital transcranial magnetic stimulation (TMS) underwent 60 min of complete LD. Phosphene threshold (PT) was measured before (T0), after 45 min (T1) and 60 min (T2) of LD, and then every 10 min after light re-exposure until recovery to T0 values. Repetitive TMS (rTMS) (at 1 or 10 Hz) was applied in separate sessions during the last 15 min of LD. PTs significantly decreased after 45 min of LD. rTMS differentially modified the effects of 60 min LD on PTs depending on stimulation frequency. One hertz rTMS did not change the decreasing of PT values as observed in baseline condition, but significantly prolonged the time to recover T0 PT values after light re-exposure. By contrast, 10 Hz rTMS significantly increased PT and the time to recover T0 PT values after light re-exposure was shortened. The results of this study show that the modulatory effects of different rTMS frequencies on visual cortex critically depend on the pre-existing excitability state of inhibitory and facilitatory circuits, and provide novel insights into the neurophysiological changes that take place in the visual cortex following functional visual deafferentation. [source] Comparison of Quantitative T-Wave Alternans Profiles of Healthy Subjects and ICD PatientsANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 2 2009B.Eng., Euler De Vilhena Garcia Ph.D., M.Sc. Background: Current relevance of T-wave alternans is based on its association with electrical disorder and elevated cardiac risk. Quantitative reports would improve understanding on TWA augmentation mechanisms during mental stress or prior to tachyarrhythmias. However, little information is available about quantitative TWA values in clinical populations. This study aims to create and compare TWA profiles of healthy subjects and ICD patients, evaluated on treadmill stress protocols. Methods: Apparently healthy subjects, not in use of any medication were recruited. All eligible ICD patients were capable of performing an attenuated stress test. TWA analysis was performed during a 15-lead treadmill test. The derived comparative profile consisted of TWA amplitude and its associated heart rate, at rest (baseline) and at peak TWA value. Chi-square or Mann-Whitney tests were used with p values , 0.05. Discriminatory performance was evaluated by a binary logistic regression model. Results: 31 healthy subjects (8F, 23M) and 32 ICD patients (10F, 22M) were different on baseline TWA (1 ± 2 ,V; 8 ± 9 ,V; p < 0.001) and peak TWA values (26 ± 13 ,V; 37 ± 20 ,V; p = 0,009) as well as on baseline TWA heart rate (79 ± 10 bpm; 67 ± 15 bpm; p < 0.001) and peak TWA heart rate (118 ± 8 bpm; 90 ± 17 bpm; p < 0.001). The logistic model yielded sensitivity and specificity values of 88.9% and 92.9%, respectively. Conclusions: Healthy subjects and ICD patients have distinct TWA profiles. The new TWA profile representation (in amplitude-heart rate pairs) may help comparison among different research protocols. [source] Mathematical modeling of the circadian rhythm of key neuroendocrine,immune system players in rheumatoid arthritis: A systems biology approachARTHRITIS & RHEUMATISM, Issue 9 2009Michael Meyer-Hermann Objective Healthy subjects and patients with rheumatoid arthritis (RA) exhibit circadian rhythms of the neuroendocrine,immune system. Understanding circadian dynamics is complex due to the nonlinear behavior of the neuroendocrine,immune network. This study was undertaken to seek and test a mathematical model for studying this network. Methods We established a quantitative computational model to simulate nonlinear interactions between key factors in the neuroendocrine,immune system, such as plasma tumor necrosis factor (TNF), plasma cortisol (and adrenal cholesterol store), and plasma noradrenaline (NA) (and presynaptic NA store). Results The model was nicely fitted with measured reference data on healthy subjects and RA patients. Although the individual circadian pacemakers of cortisol, NA, and TNF were installed without a phase shift, the relative phase shift between these factors evolved as a consequence of the modeled network interactions. Combined long-term and short-term TNF increase (the "RA model") increased cortisol plasma levels for only a few days, and cholesterol stores started to become markedly depleted. This nicely demonstrated the phenomenon of inadequate cortisol secretion relative to plasma TNF levels, as a consequence of adrenal deficiency. Using the RA model, treatment with glucocorticoids between midnight and 2:00 AM was found to have the strongest inhibitory effect on TNF secretion, which supports recent studies on RA therapy. Long-term reduction of TNF levels by simulation of anti-TNF therapy normalized cholesterol stores under "RA" conditions. Conclusion These first in silico studies of the neuroendocrine,immune system in rheumatology demonstrate that computational biology in medicine, making use of large collections of experimental data, supports understanding of the pathophysiology of complex nonlinear systems. [source] Absence of clinically relevant drug interactions following simultaneous administration of didanosine-encapsulated, enteric-coated bead formulation with either itraconazole or fluconazoleBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 2 2002B. Damle Abstract This open-label, two-way crossover study was undertaken to determine whether the enteric formulation of didanosine influences the pharmacokinetics of itraconazole or fluconazole, two agents frequently used to treat fungal infections that occur with HIV infection, and whose bioavailability may be influenced by changes in gastric pH. Healthy subjects were randomized to Treatment A (200-mg itraconazole or 200-mg fluconazole) or Treatment B (same dose of itraconazole or fluconazole with 400 mg of didanosine as an encapsulated, enteric-coated bead formulation). In the itraconazole study, a lack of interaction was concluded if the 90% confidence interval (CI) of the ratio of the geometric means of log-transformed Cmax and AUC0,T values of itraconazole and hydroxyitraconazole, the active metabolite of itraconazole, were contained entirely between 0.75 and 1.33. In the fluconazole study, the equivalence interval for Cmax and AUC0,T was 0.80,1.25. The data showed that for itraconazole the point estimate and 90% CI of the ratios of Cmax and AUC0,T values were 0.98 (0.79, 1.20) and 0.88 (0.71, 1.09), respectively; for hydroxyitraconazole the respective values were 0.91 (0.76, 1.08) and 0.85 (0.68, 1.06). In the fluconazole study, the point estimate and 90% CI of the ratios of Cmax and AUC0,T values were 0.98 (0.93, 1.03) and 1.01 (0.99, 1.03), respectively. The Tmax for itraconazole, hydroxyitraconazole, and fluconazole were similar between treatments. Both studies indicated a lack of clinically significant interactions of the didanosine formulation with itraconazole or fluconazole. These results showed that the encapsulated, enteric-coated bead formulation of didanosine can be concomitantly administered with drugs, such as the azole antifungal agents, whose bioavailability may be influenced by interaction with antacids. Copyright © 2002 John Wiley & Sons, Ltd. [source] A functional magnetic resonance imaging study of cortical asymmetry in bipolar disorderBIPOLAR DISORDERS, Issue 3 2004Michael P Caligiuri Objectives:, Individuals with bipolar disorder (BPD) exhibit motor, perceptual, and cognitive disturbances involving predominantly right hemisphere dysfunction. This asymmetry has been used to advance the hypothesis that the pathogenesis of bipolar disorder may be related to disturbances of the right cerebral hemisphere. We employed functional magnetic resonance imaging to examine hemispheric asymmetries in manic and depressed BPD. A secondary goal of the study was to examine effects of psychotropic medications on blood volume changes in the motor cortices. Methods:, We studied 18 right-handed BPD and 13 right-handed normal healthy comparison subjects. Blood oxygen level dependent (BOLD) responses in the primary motor area (M1) and supplementary motor area (SMA) of both hemispheres were elicited during reaction time (RT) tasks. Results:, Healthy subjects activated the SMA in a reciprocal fashion with significantly greater activity in the left SMA for right hand trials and the right SMA for left hand trials. Depressed BPD subjects failed to show this normal reciprocity indicating a failure to suppress unwanted activity in the ipsilateral right SMA, whereas manic BPD subjects failed to suppress unwanted ipsilateral SMA activity in both hemispheres. Manic and depressed BPD subjects exhibited greater activity in the left primary motor area suggesting increased cortical excitability. BPD subjects treated with antipsychotics or mood-stabilizing medications exhibited longer RTs, lower BOLD responses in M1 and SMA, and a loss of normal hemispheric asymmetry in the SMA than untreated subjects. Conclusions:, The presence of a right hemisphere disturbance in BPD is consistent with the hypothesis that the right hemisphere may be dominant in mood regulation. The presence of both left and right hemisphere disturbances in mania may explain the coexisting psychotic and affective symptoms observed in this condition. [source] Lamotrigine does not prolong QTc in a thorough QT/QTc study in healthy subjectsBRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue 3 2008Ruth Dixon WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT , Drugs that inhibit the human cardiac delayed rectifier potassium current may lead to prolongation of the cardiac QT interval and are associated with a fatal, polymorphic, ventricular tachycardia known as torsades de pointes. , Lamotrigine is indicated in the treatment of epilepsy and the prevention of mood episodes in patients with bipolar disorder. , Lamotrigine inhibits the human cardiac delayed rectifier potassium current in vitro, and it has been hypothesized that QT prolongation may contribute to the risk of sudden unexpected death in epilepsy patients. WHAT THIS STUDY ADDS , This is the first reported thorough QT/QTc study with lamotrigine conducted to International Conference on Harmonization guidelines. , The mean QTc interval was not prolonged by lamotrigine in healthy subjects, as assessed by the standard heart rate correction methods (Fridericia's and Bazett's). , The in vitro inhibition of the delayed rectifier potassium current does not translate into an effect on QT in man. AIM To characterize the effects of lamotrigine on QT interval in healthy subjects. METHODS Healthy subjects received a single oral dose of moxifloxacin (400 mg) or placebo in crossover design, followed by a dose-escalating regimen of lamotrigine (n = 76) over a 77-day period, or matched placebo (n = 76). Blood samples were taken for determination of moxifloxacin and lamotrigine concentrations and digital 12-lead ECGs were recorded. The relationships between individual QT values and respective individual moxifloxacin or lamotrigine concentrations were explored using population pharmacokinetic,pharmacodynamic (PK,PD) modelling. RESULTS Moxifloxacin was associated with a maximum mean increase from baseline in QTcF of 14.81 ms [90% confidence interval (CI) 13.50, 16.11] 2.5 h after dosing. Steady-state exposure to lamotrigine (50, 150 or 200 mg b.d.) was not associated with an increase in QTc interval. Small reductions in QTcF (maximum mean difference from placebo ,7.48 ms, 90% CI ,10.49, ,4.46) and small increases in heart rate (maximum mean difference from placebo 5.94 bpm, 90% CI 3.81, 8.06) were observed with lamotrigine 200 mg b.d. vs. placebo. No effect of lamotrigine on QRS duration or blood pressure was observed. No outliers with QTcF > 450 ms, or with an increase from baseline of >60 ms were observed in the lamotrigine group. PK,PD modelling indicated statistically significant decreases in individually corrected QT intervals for lamotrigine and statistically significant increases in individually corrected QT intervals for moxifloxacin over the concentration ranges studied. CONCLUSIONS Therapeutic doses of lamotrigine (50,200 mg b.d.) were not associated with QT prolongation in healthy subjects. [source] The effects of ziprasidone on steady-state lithium levels and renal clearance of lithiumBRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue S1 2000G. Apseloff Aims, To assess the potential of ziprasidone to alter the renal clearance and steady-state serum levels of lithium. Methods, Healthy subjects who had stable serum lithium levels during the first 7 days of treatment with lithium 900 mg day,,1, given as two divided daily doses, were randomized to receive concomitant treatment with either ziprasidone, 40 mg day,,1, given as two divided daily doses, on days 9,11 followed by 80 mg day,,1, given as two divided daily doses on days 12,15 (n = 12), or placebo twice daily (n = 13). Ziprasidone or placebo was administered 2 h before each dose of lithium. Results, Ziprasidone administration was associated with a 0.07 mmol l,,1 (13%) mean increase in steady-state serum lithium levels compared with a mean increase of 0.06 mmol l,,1 (10%) with placebo. Mean renal clearance of lithium decreased by 0.09 l h,,1 (5%) in the ziprasidone group and by 0.14 l h,,1 (9%) in the placebo group. None of these differences between the two groups was statistically or clinically significant. Conclusions, Ziprasidone does not alter steady-state serum lithium concentrations or renal clearance of lithium. [source] Subjective memory decline in healthy community-dwelling elders.ACTA NEUROLOGICA SCANDINAVICA, Issue 3 2010What does this complain mean? Balash Y, Mordechovich M, Shabtai H, Merims D, Giladi N. Subjective memory decline in healthy community-dwelling elders. What does this complain mean? Acta Neurol Scand: 2010: 121: 194,197. © 2009 The Authors Journal compilation © 2009 Blackwell Munksgaard. Objectives,,, Subjective feelings of memory decline are fairly common among the elderly. The causes of this are heterogeneous, and may be related to both affective and cognitive disorders. We attempted to explore the associations between subjective and cognitive measures. Materials and Methods,,, Healthy subjects were studied. They completed questionnaires regarding memory difficulties and lifestyle habits, the Geriatric Depression scale (GDS), and the Spielberger State-Trait Anxiety Inventory. Cognitive functions were tested using the Mini-Mental State Exam and supplemented with NeuroTrax, a computerized neurophysiological battery. Univariate logistic regression model was applied to estimate odd ratios (OR) and 95% confidence intervals of associations. Results,,, Of 341 consecutive non-depressed subjects, 257 participants (75.4%) reported subjective memory decline (SMD). Subjects with and without SMD did not differ in age, gender, education, marital status, employment and life-style. Subjects with SMD had elevated GDS scores (OR = 1.14, 95% CI: 1.003,1.29), white anxiety level showed a tendency to be increased (OR = 1.03, 95% CI: 0.99,1.06). Comparison of cognitive performance has not revealed differences in cognitive domains between subjects with and without SMD. Conclusions,,, SMD in healthy elderly people is associated with sub-clinical depression even among those without objectively measured cognitive decline. [source] Higher immunoglobulin E antibody levels to recombinant Fel d 1 in cat-allergic children with asthma compared with rhinoconjunctivitisCLINICAL & EXPERIMENTAL ALLERGY, Issue 8 2008H. Grönlund Summary Background Current diagnosis of allergy and asthma to cat is confirmed using cat dander extract (CDE). We have previously engineered a recombinant major cat allergen, rFel d 1, with properties identical to the natural molecule. Objective The aim of the study was to evaluate IgE and IgG4 antibodies to rFel d 1 among sera from cat-allergic children and adults suffering from asthma and/or rhinoconjunctivitis (RC) in populations from Sweden and Austria. Methods Cat-allergic children and adults from Sweden (n=27 and 31, respectively) and Austria (n=41 and 41) with RC and/or asthma were selected. Sera were tested for IgE and IgG4 antibodies to CDE and rFel d 1 by CAP, and IgE to rFel d 1 by ELISA. Healthy subjects and non-cat-allergic patients (n=75) were included as controls. Results There was a high correlation between IgE responses to rFel d 1 and CDE among the 140 patients (rs=0.85, P<0.001); however, measured levels to rFel d 1 were on average 30% higher (P<0.0001). Ninety-eight percent of patients and none of the controls showed IgE to rFel d 1 and there was a threefold increased risk of asthma for half of the children with the highest IgE levels [odds ratio 3.23; 95% confidence interval (CI), 1.19,8.79] by ELISA. IgE responses to rFel d 1 among children with asthma were higher (median 19.4 kU/L) compared with children with RC (median 6.6 kU/L, P<0.05) and adults with asthma (median 3.0 kU/L, P<0.01). Furthermore, children with asthma displayed higher IgG4 levels than the asthmatic adults. Conclusion A single recombinant molecule, rFel d 1, is at least as sensitive for in vitro diagnostics of cat allergy as the current extract-based test. Elevated IgE antibody levels to Fel d 1 are suggested to be a risk factor for asthma in cat-allergic children. [source] Anaerobic thyroid abscess from a thyroid cyst after fine-needle aspirationHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 1 2002Jui-Hung Sun MD Abstract Background Anaerobic abscess formation within a thyroid cyst is rare but still possible, although aerobic thyroid abscess formation in the thyroid gland after fine-needle aspiration (FNA) has been observed in immunocompromised patients. Methods This study describes the clinical manifestations, thyroid echography, cytologic finding, culture outcome, and treatment course of an anaerobic abscess formation within a thyroid cyst after FNA in a healthy subject. Results A 53-year-old male subject had rapid enlargement of a left thyroid cyst develop after second FNA. Frank pus was obtained through third FNA. The culture outcome was Propionibacterium acnes, which was rich in saliva and one of the pathogens causing periodontitis and gingivitis. After adequate antimicrobial therapy, the abscess gradually diminished. Conclusions This article reported, for the first time, on the formation of an anaerobic thyroid abscess after FNA in a healthy subject. We recommended careful aseptic procedure and adequate isolation processes, such as wearing a mask to avoid an unfavorable outcome as a result of a bacterial infection. © 2002 John Wiley & Sons, Inc. Head Neck 24: 84,86, 2002. [source] Single-scan acquisition of registered hyperpolarized 3He ventilation and ADC images using a hybrid 2D gradient-echo sequenceMAGNETIC RESONANCE IN MEDICINE, Issue 6 2007Jim M. Wild Abstract The pulse sequences for hyperpolarized 3He lung MRI that have made the most clinical impact to date are 1) those that supply regional apparent diffusion coefficient (ADC) measurements, which provide insight into early emphysematous destruction of the alveoli in the lungs, and 2) high-resolution ventilation images that provide regional indicators of airway obstruction in obstructive airway disease, such as asthma, cystic fibrosis, and chronic obstructive pulmonary disease (COPD). In this work a hybrid 2D ADC-ventilation sequence was used with low flip angles to acquire both sets of data in the same breath-hold. The performance of the sequence was investigated in vivo in a healthy subject and a subject with mild emphysema, and compared with conventional 2D gradient-echo (GRE) 3He ventilation and ADC imaging sequences. Acquisition of the ADC and ventilation images in one breath-hold provides ventilation images with equal or better SNR (,20) and the same spatial resolution (3.75 mm × 3.3 mm in plane) with simultaneous accurate, high-resolution ADC images. The hybrid sequence offers a means of conserving gas by using two-thirds of the 3He gas needed for separate ADC and ventilation exams, and saves the subject from having to perform an extra breath-hold. The data are inherently spatially and temporally registered, allowing quantitative cross-correlation between high-spatial-resolution ADC and ventilation data. Magn Reson Med 57:1185,1189, 2007. © 2007 Wiley-Liss, Inc. [source] Virtual Laryngoscopy: a Noninvasive Tool for the Assessment of Laryngeal Tumor ExtentTHE LARYNGOSCOPE, Issue 6 2007Yuling Yan PhD Abstract Objectives: Present a clinical application of virtual laryngoscopy (VL) in the assessment of laryngeal tumor and its extent. Study Design: CT data from two subjects are acquired for this preliminary study. One subject is a healthy volunteer and the other is a patient with laryngeal tumor. The laryngeal framework and upper airway are reconstructed using CT data, which allows for computer-aided internal and external anatomical views and interactive fly-through. Methods: These CT data are reconstructed into 0.5 mm slice images, resulting in a total of 200,300 image slices. An advanced commercial visualization software (AMIRA) is used for 3D image segmentation, reconstruction and surface rendering of laryngeal anatomical structures. Results: The 3D laryngeal framework and upper airway are reconstructed for both the tumor patient and the healthy subject. The conventional views of the reconstructed vocal folds are compared with those obtained from fiber-optic laryngoscope. Additionally, unique views of the vocal folds obtained from retrograde visualization and fly-through are presented, which are not possible to obtain using conventional endoscope imaging. The segmented anatomical model and the tumor from the patient's CT images were displayed individually to show the distribution of the tumor and its extent as well as spatial and contextual relationships to the larynx and airway anatomical structures. Conclusions: This study demonstrated the potential application of VL as a noninvasive clinical diagnostic tool for the assessment of laryngeal tumor and its extent. Our preliminary results demonstrated that the VL may provide valuable insights for the diagnosis and treatment planning for laryngeal and airway tumors. The noninvasive VL may complement the invasive laryngoscopic examinations for the staging of tumors and follow-ups on surgical interventions. [source] Population modelling of the effect of inogatran, at thrombin inhibitor, on ex vivo coagulation time (APTT) in healthy subjects and patients with coronary artery diseaseBRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue 1 2001Marie Cullberg Aims, The purpose of this study was to characterize the relationship between the degree of anticoagulation, assessed by APTT, and the plasma concentration of inogatran in healthy subjects and in patients with coronary artery disease. Methods, Data from five phase I studies in 78 healthy males and two phase II multicentre studies in 948 patients of both sexes with unstable angina pectoris or non-Q-wave myocardial infarction were evaluated. A total of 3296 pairs of concentration-APTT samples were obtained before, during, and after intravenous infusions of inogatran. Mixed effects modelling was used for population pharmacodynamic analysis of the drug effect and for describing the variability in baseline APTT. Results, The population mean baseline APTT was 29 s, but large variations between individuals (s.d. 3.6 s) were observed. The variability between studies (1.3 s) and centres (1.8 s) were of less importance, though statistically significant. APTT increased in a nonlinear manner with increasing inogatran concentration and the relationship was well described by a combined linear and Emax model. A significant part of the overall variability could be ascribed to the APTT reagent and equipment used at the different study centres. These method-dependent differences were compensated for by including the lower limit of the normal reference range as a covariate, affecting both baseline and Emax, in the model. For the typical healthy subject and patient, the method-corrected population mean parameters were: APTTbaseline 35 and 31 s, slope 8.0 and 5.8 s l µmol,1, Emax 36 and 34 s, and EC50 0.54 and 0.72 µmol l,1, respectively. The model predicted plasma concentration needed to double the APTT from the baseline value was 1.25 and 1.45 µmol l,1 in the healthy volunteer and patient, respectively. Conclusions, The nonlinear relationship between APTT and inogatran concentration in plasma was well described by a combined linear and Emax model. Pooling of data was made possible by incorporating a centre-specific characteristic of the assay method in the model. Patients had lower baseline APTT and appeared to have less pronounced effect of inogatran than young healthy subjects. [source] 4352: Retrobulber imag,ng in glaucoma w,th d,ffus,on tensor MRI/opt,c tractography and fMRI: structural and funct,onal analys,sACTA OPHTHALMOLOGICA, Issue 2010KN ENGIN Purpose Evidences today proves that, glaucomateus damage proceeds from retinal ganglion cells to brain. The purpose of this study is to demonstrate the structural and functional eye-brain connection in glaucoma, to develop favourable clinical methods for both glaucoma follow ups and large clinical trials, and finally, to establish a reference for further studies regarding pathogenesis, evaluation and treatment of glaucoma. Methods Four glaucoma cases with symetrical (n=2) and asymetrical (n=2) involvement and 1 healthy subject are included in this study. Glaucoma analysis with optic coherens tomography (OCT) and central visual field (CVF) results of the subjects were recorded. By using diffusion-tensor magnetic resonance imaging (DT-MRI) technique, 3D-T1 weighted images of the optic nerves and optic tracts were taken with optic tractography (OT). Then DT-MRI parameters obtained from each patient were compared with the fellow eye and the healthy subject. Retinotopic Organizations (RO) of primary visual cortexes were produced from functional magnetic resonance imaging (fMRI) images and BOLD signals were evaluated with reciprocal CVF defects. All images were taken with 1,5T MRI system. Results In DT-MRI analysis, optic nerve volume, FA were found to be decreased in the eyes with severe RNFL loss. Optic nerve and tract deformation were showed with both OT and B0 coronal plane images. Lower bold signals were detected in the eyes of asymetric patients with severe glaucoma and in quadrants with large CVF defects. Conclusion Strategies concerning beyond optic nerve head are needed in glaucoma. Structural and functional analysis can be made by taken together the OCT and DT-MRI findings and CVF and fMRI findings, respectively. [source] Mechanisms of exercise-induced improvements in the contractile apparatus of the mammalian myocardiumACTA PHYSIOLOGICA, Issue 4 2010O. J. Kemi Abstract One of the main outcomes of aerobic endurance exercise training is the improved maximal oxygen uptake, and this is pivotal to the improved work capacity that follows the exercise training. Improved maximal oxygen uptake in turn is at least partly achieved because exercise training increases the ability of the myocardium to produce a greater cardiac output. In healthy subjects, this has been demonstrated repeatedly over many decades. It has recently emerged that this scenario may also be true under conditions of an initial myocardial dysfunction. For instance, myocardial improvements may still be observed after exercise training in post-myocardial infarction heart failure. In both health and disease, it is the changes that occur in the individual cardiomyocytes with respect to their ability to contract that by and large drive the exercise training-induced adaptation to the heart. Here, we review the evidence and the mechanisms by which exercise training induces beneficial changes in the mammalian myocardium, as obtained by means of experimental and clinical studies, and argue that these changes ultimately alter the function of the whole heart and contribute to the changes in whole-body function. [source] Use of in vitro release of interferon-, in the diagnosis of contact allergy to potassium dichromate , a controlled studyCONTACT DERMATITIS, Issue 4 2003A. Trattner The use of in vitro release of interferon-, (IFN-,) in the diagnosis of contact allergy to potassium dichromate was studied in 20 patients who had positive patch tests to chromate and in 30 control subjects (10 patients with contact dermatitis, allergic to other allergens, 10 patients with other dermatologic diseases and 10 healthy subjects). The release of IFN-, in the supernatants of the peripheral blood lymphocytes was significantly higher in the patients with proven allergy to chromate (P = 0·001). Further studies are needed to determine if IFN-, release may serve as an additional diagnostic tool in contact dermatitis. [source] | |||||||||||||||||||||||||||||||||||||||||||