Median Slope Research Articles

How and when human chorionic gonadotropin curves in women with an ectopic pregnancy mimic other outcomes: differences by race and ethnicity

To investigate the hCG profiles in a diverse patient group with ectopic pregnancy (EP) and to understand when they may mimic the curves of an intrauterine pregnancy (IUP) or spontaneous abortion (SAB). Retrospective cohort study. Three university hospitals. One hundred seventy-nine women with symptomatic pregnancy of unknown location. None. Slope of log hCG; days and visits to final diagnosis. Of women with an EP, 60% initially exhibited an increase in hCG values, with a median slope of 32% increase in 2 days; 40% of subjects initially had an hCG decrease, with the median slope calculated as a 15% decline in 2 days. In total, the hCG curves in 27% of women diagnosed with EP resembled that of a growing IUP or SAB. Of the EP hCG curves, 16% demonstrated a change in the direction of the slope of the curve. This was more common in African Americans and less evident in Hispanics. Furthermore, it was associated with more clinical visits and days until final diagnosis. The rate of change in serial hCG values can be used to distinguish EP from an IUP or SAB in only 73% of cases. The number of women who had a change in direction of serial hCG values was associated with race and ethnicity.

The effects of triceps surae fatigue on the torque and electromyographic parameters in athletes compared with non-athletes

The common description of muscular fatigue is the failure of muscle in maintaining a target force. Even in sustained contraction, when muscle force is held at a stable level, physiological, biomechanical and electromyographic changes can occur. The purpose of this study is to compare the effects of triceps surae (TS) fatigue on the torque, falling slope and electromyographic (EMG) parameters between athletes and non-athletes. Nineteen healthy women (10 non-athletes and 9 basketball players) participated in this study. After warm-up, subjects performed one maximum voluntary contraction (MVC) followed by fatigue test including sustained maximum isometric contraction of TS until the peak torque (PT) decreased to 50% of maximum value. Immediately after the test, subjects were asked to perform one MVC; then, root mean square (RMS), median frequency (MDF), median frequency slope (MDF slope), PT, falling slope (FSL) and the amount of pain were measured. In both groups shift of MDF slope to negative values, significant decrease of MDF and RMS occurred at the end of the fatigue test (P < 0.05). Immediately after the test, PT decreased significantly in both groups (P < 0.05), however, decrease of FSL was significant in non-athletes (P < 0.05) but not in athletes. After fatigue test, increase in Pain was significant in both groups (P < 0.05). Before fatigue test, at the end, and immediately after the test, MDF of non-athletes was more than athletes. There was no significant difference in RMS between the two groups. Our findings suggest that TS fatigue affects EMG parameters, PT and pain in athletes and non-athletes similarly.

Spectral analysis of electromyographic signal in supramaximal effort in cycle ergometer using Fourier and Wavelet transforms: a comparative study

ObjectiveThe objective of this study was to compare these methods Fourier (STFT) and Wavelet (WT) transforms to assess muscle fatigue during supramaximal exercise. MethodsTwenty five subjects of both genders (13 men, age = 28.2±2.7 years and 12 women, age = 23.2±2.7 years) performed the Wingate test, during which the electromyographic responses of the superficial muscles of the quadriceps were examined. For analysis we used the STFT and WT transforms, which provided the following variables: median frequency (MF), slope and variance. ResultsThe results showed no differences (P>0.05) in MF and slope. However, there were differences for the variance between the analysis (P<0.05). ConclusionIt seems that both analyzes provide the same physiological parameters, however, the WT transform shows less variance between the results.

Correlation between coronary perfusion pressure and quantitative ECG waveform measures during resuscitation of prolonged ventricular fibrillation

IntroductionThe ventricular fibrillation (VF) waveform is dynamic and predicts defibrillation success. Quantitative waveform measures (QWMs) quantify these changes. Coronary perfusion pressure (CPP), a surrogate for myocardial perfusion, also predicts defibrillation success. The relationship between QWM and CPP has been preliminarily explored. We sought to further delineate this relationship in our porcine model and to determine if it is different between animals with/without ROSC (return of spontaneous circulation). HypothesisA relationship exists between QWM and CPP that is different between animals with/without ROSC. MethodsUtilizing a prior experiment in our porcine model of prolonged out-of-hospital VF cardiac arrest, we calculated mean CPP, cumulative dose CPP, and percent recovery of three QWM during resuscitation before the first defibrillation: amplitude spectrum area (AMSA), median slope (MS), and logarithm of the absolute correlations (LAC). A random effects linear regression model with an interaction term CPP*ROSC investigated the association between CPP and percent recovery QWM and how this relationship changes with/without ROSC. ResultsFor 12 animals, CPP and QWM measures (except LAC) improved during resuscitation. A linear relationship existed between CPP and percent recovery AMSA (coefficient 0.27; 95%CI 0.23, 0.31; p<0.001) and percent recovery MS (coefficient 0.80; 95%CI 0.70, 0.90; p<0.001). A linear relationship existed between cumulative dose CPP and percent recovery AMSA (coefficient 2.29; 95%CI 2.0, 2.56; p<0.001) and percent recovery MS (coefficient 6.68; 95%CI 6.09, 7.26; p<0.001). Animals with ROSC had a significantly “steeper” dose–response relationship. ConclusionsThere is a linear relationship between QWM and CPP during chest compressions in our porcine cardiac arrest model that is different between animals with/without ROSC.

Switching virally suppressed, treatment-experienced patients to a raltegravir-containing regimen does not alter levels of HIV-1 DNA.

BackgroundCurrent HIV-1 antiretroviral therapy (ART) greatly reduces virus replication but does not significantly affect the viral reservoir. Raltegravir, a recently introduced integrase inhibitor, could, at least theoretically, reduce residual viremia in patients on ART and affect the viral reservoir size. The aim of this study was to assess whether switching therapy in treatment-experienced patients that were virally suppressed to a raltegravir-containing regimen reduces the size of the viral reservoir, and if such treatment leads to a change in levels of HIV 2-LTR circles in this patient group.Methods14 ART experienced individuals with a suppressed viral load (<50 HIV-1 RNA copies/mL plasma) at baseline (for at least 2 months) were switched to a raltegravir-containing regimen. Blood samples were taken at baseline and at ≥2 timepoints up to 48±6 weeks. Levels of total HIV-1 DNA and 2-LTR circles in peripheral blood mononuclear cells (PBMCs) were measured using real-time PCR assays.ResultsThere was no significant change in HIV-1 total DNA levels over the study duration (p = 0.808), median slope 0.24 (conservative nonparametric 95% CI: −11.78, 26.23). Low levels of 2-LTR circles were detected in 2 patients. One had 16 copies/106 PBMCs at baseline and the other had 34 copies/106 PBMCs at week 51.ConclusionsThe switch to a raltegravir containing regimen was not associated with a significant change in HIV-1 total DNA levels in this cohort. There were no observed changes in the levels of HIV-1 2-LTR circles associated with raltegravir treatment initiation.

Effect of hydraulic parameters on sediment transport capacity in overland flow over erodible beds

Abstract. Sediment transport is an important component of the soil erosion process, which depends on several hydraulic parameters like unit discharge, mean flow velocity, and slope gradient. In most of the previous studies, the impact of these hydraulic parameters on transport capacity was studied for non-erodible bed conditions. Hence, this study aimed to examine the influence of unit discharge, mean flow velocity and slope gradient on sediment transport capacity for erodible beds and also to investigate the relationship between transport capacity and composite force predictors, i.e. shear stress, stream power, unit stream power and effective stream power. In order to accomplish the objectives, experiments were carried out in a 3.0 m long and 0.5 m wide flume using four well sorted sands (0.230, 0.536, 0.719, 1.022 mm). Unit discharges ranging from 0.07 to 2.07 × 10−3 m2 s−1 were simulated inside the flume at four slopes (5.2, 8.7, 13.2 and 17.6%) to analyze their impact on sediment transport rate. The sediment transport rate measured at the bottom end of the flume by taking water and sediment samples was considered equal to sediment transport capacity, because the selected flume length of 3.0 m was found sufficient to reach the transport capacity. The experimental result reveals that the slope gradient has a stronger impact on transport capacity than unit discharge and mean flow velocity due to the fact that the tangential component of gravity force increases with slope gradient. Our results show that unit stream power is an optimal composite force predictor for estimating transport capacity. Stream power and effective stream power can also be successfully related to the transport capacity, however the relations are strongly dependent on grain size. Shear stress showed poor performance, because part of shear stress is dissipated by bed irregularities, bed form evolution and sediment detachment. An empirical transport capacity equation was derived, which illustrates that transport capacity can be predicted from median grain size, total discharge and slope gradient.

Temporal pattern of aridity index in Iran with considering precipitation and evapotranspiration trends

AbstractThe knowledge of aridity is needed to explain landscape characteristics and the rational utilization of water resources. With global warming, an increase in aridity is expected for many parts of the world. This study was undertaken to analyse monthly and annual aridity index (IA), utilizing ratio of precipitation (P) over reference evapotranspiration (ETo), at ten stations located in critical agricultural regions in Iran. The Kendall and Spearman tests with considering serial correlation effect were used for analysis. An increase in aridity, as the P/ETo index decreased, was found during the study period, and the increase was more obvious in the semi‐arid region of Iran than in the humid region. The increase of aridity was caused by the concurrent occurrences of negative P trends and positive ETo trends. The results indicated the lowest numbers of the negative IA trends in the July series and the highest numbers in the January, February and March series. According to the Theil–Sen's estimator, the annual P of the semi‐arid and humid regions decreased at the average rates of (−)22.87 and (−)6.24 mm year−1 per decade respectively, whereas the annual ETo values in the semi‐arid and humid regions increased by (+)11.42 and (+)6.82 mm year−1 per decade, respectively. Copyright © 2012 Royal Meteorological Society

Dried Blood Spot Samples for Seroepidemiology of Infections with Human Papillomaviruses, Helicobacter pylori, Hepatitis C Virus, and JC Virus

To establish antibody analysis from dried blood spots (DBS) on filter paper for seroepidemiologic infection and cancer association studies, we analyzed data from a population-based study in Mongolia. Using multiplex serology, we analyzed 985 paired DBS and serum samples from the same donors for antibodies to 12 different proteins from four groups of infectious agents: human papillomaviruses (HPV), Helicobacter pylori (H. pylori), hepatitis C virus (HCV), and JC polyomavirus (JCV). Quantitative antibody reactivities in serum and DBS showed good correlation, with median correlation coefficients (Pearson R(2)) of 0.88 (range, 0.80-0.90) for high-titer (i.e., H. pylori, HCV, JCV) and 0.79 (range, 0.72-0.85) for low-titer antibodies (i.e., HPV). For high-titer antibodies, serum and DBS data were comparable (median slope of linear trend line, 1.14; range, 1.09-1.21), whereas for low-titer antibodies, DBS reactivities were lower than in serum (median slope, 0.54; range, 0.50-0.80). By extrapolating seropositivity cutoff points previously defined for serum to DBS, we found high agreement (>89% for all antigens) of dichotomized DBS and serum results and median kappa values for high- and low-titer antibodies of 0.86 and 0.78 (range, 0.78-0.92 and 0.55-0.86), respectively. Epidemiologic associations with known risk factors for HPV antibodies were as strong for DBS as for serum. DBS provide a reliable alternative to serum or plasma for detection of antibodies against various pathogens by multiplex serology. DBS do not require blood centrifugation and allow storage and shipment at ambient temperature, thus facilitating field work for seroepidemiologic studies especially in environments with limited technical infrastructure.

Early Systolic Blood Pressure Changes in Incident Hemodialysis Patients Are Associated with Mortality in the First Year

Background: In incident hemodialysis (HD) patients, the relationship between early systolic blood pressure (SBP) dynamics and mortality is unknown. Methods: Baseline SBP levels were stratified into 5 categories ranging from <120 and ≥180 mm Hg. Early pre-HD SBP change was defined as the slope of pre-HD SBP from week 1 to 12 and categorized in quartiles (Q1, lowest slope). SBP slopes were computed for each patient by simple linear regression. Results: In 3,446 incident HD patients (42% females, 44% black, age 62 ± 15 years), the median pre-HD SBP slope was –1.7 (Q1) to +2.3 (Q4) mm Hg/week. In an adjusted multivariate Cox regression analysis, patients with declining SBP (slope Q1) had higher mortality compared to patients with increasing pre-HD SBP (slope Q4) at 12 months (hazard ratio 2.01, 95% confidence interval 1.35–3.01). In addition, patients with baseline pre-HD SBP <120 mm Hg showed higher mortality compared to the reference group (SBP ≥180 mm Hg) at 12 months (hazard ratio 1.89, 95% confidence interval 1.03–3.45). Conclusion: Baseline pre-HD SBP and early SBP dynamics are associated with mortality in the first year of dialysis. Patients who had low (pre-HD SBP <120 mm Hg) or declining SBP had the highest mortality rates. Particular attention is warranted in incident HD patients with low or declining SBP.

Left Ventricular Diastolic Dysfunction as a Predictor of Rapid Decline of Residual Renal Function in Patients with Peritoneal Dialysis

The aim of this study was to evaluate whether diastolic dysfunction at the start of dialysis could influence renal and cardiovascular survival rates in 82 patients undergoing peritoneal dialysis. Diastolic dysfunction was determined using left ventricular hypertrophy, the ratio of early peak transmitral inflow velocity to peak diastolic mitral annular velocity (E/E'), and left atrial volume index (LAVI). Residual renal function (RRF) was measured with 24-hour urine collections at baseline (within 1 month of beginning peritoneal dialysis) and thereafter at 6-month intervals for 2 years. To evaluate the long-term prognostic significance of diastolic dysfunction, the 4-year cardiac event-free survival was also evaluated. The median slope of RRF decline was -0.07 mL/min/mo/1.73 m(2). Forty-five patients (54.9%) with rapid RRF declines (< -0.07 mL/min/mo/1.73 m(2)) had a higher prevalence of diabetes and eccentric left ventricular hypertrophy, as well as significantly elevated E/E' ratios and LAVIs. There was a close relationship between baseline E/E' ratio (r = -0.221, P = .048), LAVI (r = -0.276, P = .015), and RRF decline rate, and both E/E' > 15 (odds ratio, 3.61; 95% confidence interval, 1.07-12.12) and LAVI > 32 mL/m(2) (odds ratio, 3.54; 95% confidence interval, 1.08-11.58) were significant independent predictors of the loss of RRF. Furthermore, E/E' > 15 also provided additional prognostic value in predicting future cardiac events (hazard ratio, 6.74; 95% confidence interval, 1.07-12.12; P = .023). Left ventricular diastolic dysfunction may be a significant predictor of rapid decline in RRF and adverse cardiac outcomes in patients starting peritoneal dialysis.

Quadriceps short-term resistance exercise in subjects with resistant hypertension

INTRODUCTION: Resistant arterial hypertension may lead to muscle disuse and reduced functional capacity due to arterial and target-organs lesions. The main objective of this work is to evaluate the quadriceps strength and fatigue tolerance after a program of resistance exercise in subjects with resistant primary hypertension. METHODS: Six patients under pharmacological treatment were submitted to a four-week resistance exercise training program for the quadriceps (8-14 repetitions, 3 sets, 3 days per week). Strength was evaluated by isometric dynamometry, as the percentage change in maximum voluntary contraction over the four week program. Fatigue was analyzed by surface electromyography, as the change in both root mean square value and intercept of median frequency slope of vastus medialis and vastus lateralis. RESULTS: Significant increase in the maximum voluntary contraction was observed (p = 0.04). Fatigue tolerance was not improved as seen by root mean square as well as in the intercept of median frequency (p &gt; 0.05). Additionally, no significant changes were observed in resting arterial blood pressure and heart rate throughout the training period. CONCLUSION: The prescribed protocol seemed to successfully increase localized muscle strength without negatively affecting the monitored cardiovascular variables in patients with resistant hypertension under pharmacological treatment.

Relationship between Bispectral Index Values and Volatile Anesthetic Concentrations during the Maintenance Phase of Anesthesia in the B-Unaware Trial

Hypnotic depth during anesthesia affects electroencephalography waveforms and electroencephalogram-derived indices, such as the bispectral index (BIS). Titrating anesthetic administration against the BIS assumes reliable relationships between BIS values, electroencephalogram waveforms, and effect site concentration, beyond loss of responsiveness. Associations among BIS, end-tidal anesthetic concentrations (ETAC), and patient characteristics were examined during anesthetic maintenance, using B-Unaware trial data. Pharmacokinetically stable ETAC epochs during intraoperative anesthetic maintenance were analyzed. A generalized estimating equation determined independent relationships among BIS, ETAC (in age-adjusted minimum alveolar concentration equivalents), patient characteristics, and 1-yr mortality. Further individual and population characteristics were explored graphically. A total of 3,347,523 data points from 1,100 patients were analyzed over an ETAC range from 0.42 to 1.51 age-adjusted minimum alveolar concentration. A generalized estimating equation yielded a best predictive equation: BIS = 62.9-1.6 (if age younger than 60 yr) -1.6 (if female) -2.5 (if American Society of Anesthesiologists physical status more than 3) -2.6 (if deceased at 1 yr) -2.5 (if N2O was not used) -1.4 (if midazolam dose more than 2 mg) -1.3 (if opioid dose more than 50 morphine equivalents) -15.4 × age-adjusted minimum alveolar concentration. Although a population relationship between ETAC and BIS was apparent, interindividual variability in the strength and reliability of this relationship was large. Decreases in BIS with increasing ETAC were not reliably observed. Individual-patient linear regression yielded a median slope of -8 BIS/1 age-adjusted minimum alveolar concentration (interquartile range -30, 0) and a median correlation coefficient of -0.16 (interquartile range -0.031, -0.50). Independent of pharmacokinetic confounding, BIS frequently correlates poorly with ETAC, is often insensitive to clinically significant changes in ETAC, and is vulnerable to interindividual variability. BIS is therefore incapable of finely guiding volatile anesthetic titration during anesthetic maintenance.

Elevated Mitochondrial Membrane Potential in CLL Cells Is Associated with a more aggressive Natural History

Abstract 1765 [Display omitted] Chronic lymphocytic leukemia (CLL) can be characterized by a variable natural history. While some patients have an aggressive disease course, others have an indolent course and never require treatment. Disease stage at diagnosis, cytogenetic changes, and mutation in the immunoglobulin hypervariable region, among other disease markers, have important prognostic contributions, but these prognostic markers do not reliably identify patients with an indolent natural history. We analyzed 174 individual patients with CLL and found that patients whose CLL cells retained a mitochondrial membrane potential (MMP) as measured by retention of the cyanine dye, JC-1, similar to normal B-lymphocytes had a particularly indolent disease course. While 73% of CLL patients had a substantial population of malignant lymphocytes with a higher mitochondrial membrane potential, 27% of patients had energetically normal CLL cells confirmed by co-immunostaining with anti-CD5 and anti-CD19. Elevated mitochondrial membrane potential is defined by the lymphocyte population having >50% of cells with a relative membrane potential (FL2/FL1=electrochemical potential/mitochondrial mass) > 2.0 (Figure 1).Patient samples from untreated patients were also organized into quintiles based upon the percentage of cells that populated the low mitochondrial membrane potential gate versus the percentage of cells that populated the high mitochondrial membrane potential gate (Figure 2). Patients in the lower quintile exhibited a predominance of cells in the low membrane potential gate across a broad range (.02%-42%) whereas patients in the upper quintile exhibited a predominance of cells in the high membrane potential gate across a much narrower range (88.6%-96.7%). [Display omitted] With up to six years of follow up, no patient with normal MMP has required treatment or has advanced beyond Rai stage 0. Cytogenetic changes in this subgroup include normal cytogenetics, del13q, del11q, trisomy12, and del6q23. Of the 30 patients where immunoglobulin heavy chain variable gene mutations were measured, no patients with low MMP had a germline configuration. Lymphocyte doubling time was calculated for all patients for whom data is available and it is interesting to note that patients falling within the first quintile exhibited a median slope value of ∼1 with a median lymphocyte doubling time of ∼1.5 years, whereas patients in the upper quintile within the upper quintile exhibited a much steeper median slope value of 23 and an accelerated lymphocyte doubling time of approximately 7 months (see Figure 3 for patient examples). [Display omitted] CLL cells with higher mitochondrial membrane potential have ultrastructural changes in the mitochondria typical of cells primarily utilizing glycolysis, but no difference in mitochondrial mass. CLL cells with a predominantly elevated MMP have increased lactate production and dramatically shortened survival when grown in media containing pyruvate as the primary energy substrate instead of glucose. These results indicate a significant difference in energy utilization and intracellular metabolism between malignant cells with normal and high MMP. Some patients with CLL cells that have elevated MMP appear to have an indolent disease course suggesting that elevated MMP does not necessarily portend an aggressive natural history, but to date, patients with CLL populations characterized by elevated MMP have encompassed the only patients in our study population who have required treatment directed at the CLL. The data indicate that analysis of the MMP in the CLL population can provide important prognostic information and may identify a population of patients with a benign course of disease. The prognostic significance of MMP in patients with CLL is independent of cytogenetics. The finding of low MMP appears to be confined to patients without a germline IGHV configuration. These results also indicate that the metabolic state of the malignant cell may play a central role in the clinical manifestation of disease and may point to the development of novel therapies that target mitochondrial respiration. Disclosures:Lamanna:Celgene Corporation:. Weiss:Celgene: Membership on an entity’s Board of Directors or advisory committees. Scheinberg:Actinium Pharmaceuticals, Inc.: Membership on an entity’s Board of Directors or advisory committees, Patents & Royalties, Research Funding.

How much water can a watershed store?

AbstractSubsurface runoff dominates the hydrology of many steep humid regions, and yet the basic elements of water collection, storage, and discharge are still poorly understood at the watershed scale. Here, we use exceptionally dense rainfall and runoff records from two Northern California watersheds (~100 km2) with distinct wet and dry seasons to ask the simple question: how much water can a watershed store? Stream hydrographs from 17 sub‐watersheds through the wet season are used to answer this question where we use a simple water balance analysis to estimate watershed storage changes during a rainy season (dV). Our findings suggest a pronounced storage limit and then ‘storage excess’ pattern; i.e. the watersheds store significant amounts of rainfall with little corresponding runoff in the beginning of the wet season and then release considerably more water to the streams after they reach and exceed their storage capacities. The amount of rainfall required to fill the storages at our study watersheds is the order of a few hundred millimeters (200–500 mm). For each sub‐watershed, we calculated a variety of topographic indices and regressed these against maximum dV. Among various indices, median gradient showed the strongest control on dV where watershed median slope angle was positively related to the maximum volume of storage change. We explain this using a hydrologically active bedrock hypothesis whereby the amount of water a watershed can store is influenced by filling of unrequited storage in bedrock. The amount of water required to activate rapid rainfall–runoff response is larger for steeper watersheds where the more restricted expansion of seepage from bedrock to the soil limits the connectivity between stored water and stream runoff. Copyright © 2011 John Wiley &amp; Sons, Ltd.

A dielectric inverse problem applied to human skin measurements during glucose excursions

A fringing field capacitive sensor has been used to measure the dielectric properties of human skin and underlying tissue in the MHz frequency range. It has recently been shown in clinical experimental studies that these dielectric properties can be related to the effects of in vivo glucose variations of the test subject. Previously, the relationship between electrical impedance and the glucose level has been established via statistical methods, such as the regression method. In this work, we explored a different approach, namely the resolution of the so-called inverse problem. First we applied the method on an artificial two-layer lossy system in order to test the sensitivity of the solution to forced changes in the layer properties and its stability to a constant setting. After validation of this method on artificial systems, a similar inverse problem was set and solved for dielectric measurements on human skin during an induced glucose excursion, where the skin is also modelled as a double-layer system. The changes of the measured permittivity and conductivity of the second layer versus the glucose changes are calculated for 22 study days. The statistical distribution shows that the median slopes of both dielectric properties are negative. These results can be used to test our hypothesis and to continue building potential explanations for the phenomena induced by the glucose changes on the skin layer dielectric parameters.

Central serotonergic activity correlates with salivary cortisol after waking in depressed patients

Aberrant patterns of cortisol secretion and serotonergic dysfunction are important features of major depressive disorder (MDD). A multitude of studies investigated the relationship between cortisol and serotonin. Increased salivary cortisol was found after waking in depressed patients (Bhagwagar et al. 2005, 2003). It is assumed that this cortisol awakening reaction (CAR) may be a more exact marker of depression instead of the general assumption of hypercortisolism (Bhagwagar et al. 2005). The present study aimed at investigating the relationship between cortisol and serotonergic function from a new angle. Loudness dependence of auditory-evoked potentials (LDAEP) indicates the activity of synaptically released serotonin. It measures the amplitude change of the auditoryevoked N1/P2 component in response to different stimulus intensities. A low LDAEP indicates a high serotonergic activity and vice versa (Juckel et al. 1996, 1997, 2004, 2007). After excluding four patients with insufficient cortisol data, 12 non-medicated MDD patients [seven females, mean age 47.9±8.6 years, mean Beck Depression Inventory (BDI-II) score 27.4±7.5, all outpatients] were compared to 16 healthy controls (nine females, mean age 50.1± 7.3 years). Structured clinical interview for DSM-IV and BDI-II were used as diagnostic instruments. Salivary cortisol samples were collected in salivettes. CAR was measured by subtracting the cortisol concentration upon waking from the cortisol concentration 30 min after getting up. A time-resolved immunoassay with fluorescence detection was used for cortisol analysis (Lederbogen et al. 2010). Auditory-evoked potentials were tested using a standard procedure. Three hundred fifty sinus tones of five different intensities (60–100 dB SPL) were presented in a pseudorandomised way using Presentation 11.3® (Neurobehavioral Systems Inc., Albany, CA, USA). Artifact-free stimuli were averaged with BrainVision Analyzer® (Brain Products GmbH, Munich, Germany). The N1 amplitude was regarded as the lowest point between 50 and 150 ms after the stimulus, P2 as the highest point between 100 and 250 ms post-stimulus and the N1/P2 amplitude was calculated as the amplitude difference. The LDAEP was calculated as the median slope of the single loudness levels (for further details see Roser et al. 2009). There were no significant differences between patients and controls regarding CAR levels (patients, 7.06±10.07; controls, 13.19±9.70; t test, p=0.129). There was a nonsignificant tendency towards a decreased LDAEP in depressed patients (0.13±0.18) compared to healthy controls (0.24±0.17; t test, p=0.089). I. Uhl (*) : C. Norra :G. Juckel Department of Psychiatry, Psychotherapy and Preventive Medicine, Ruhr University Bochum, LWL University Hospital Bochum, Alexandrinenstrasse 1-3, 44791 Bochum, Germany e-mail: idun.uhl@wkp-lwl.org

Long-term Trends In Cardiorespiratory Fitness And The Incidence Of Hypertension

PURPOSE: Cardiorespiratory fitness is inversely associated with a decreased risk of hypertension. However, there is little information available on the relationship between long-term trends in cardiorespiratory fitness and the incidence of hypertension. We investigated the relationship between long-term trends in fitness and the incidence of hypertension in Japanese males. METHODS: A cohort of 3,650 Japanese men free of hypertension completed annual health check-ups and cardiorespiratory fitness tests for estimated maximal oxygen uptake at least four times over seven years (1979-1985). We modeled the trend in fitness over seven years for each man using simple linear regression. Men were then divided into quartiles based on the regression coefficient (slope) from the model. During the follow-up period 1985-2004, 486 men developed hypertension. Odds ratios and 95% confidence interval (95% CI) for the incidence of hypertension were obtained using the logistic regression model. RESULTS: Men in the lowest quartile of the distribution decreased in cardiorespiratory fitness over the seven years (median slope, -1.26 ml/kg/min), while men in the highest quartile increased in fitness (median slope, 1.31 ml/kg/min). Adjusting for age, initial fitness level, body mass index, cigarette smoking, alcohol intake, and a family history of hypertension: and using the lowest quartile as reference, the odds ratios and 95% CI for the 2nd through 4th quartiles were 0.81 (0.60-1.09), 0.84 (0.62-1.16), and 0.58 (0.41-0.82), respectively (P = 0.006 for trend). CONCLUSIONS: These findings suggest that long-term trends in cardiorespiratory fitness is a predictor of the incidence of hypertension in Japanese males.

Comparing the Strength of Association of Two Predictors via Smoothers or Robust Regression Estimators

Consider three random variables, Y , X1 and X2, having some unknown trivariate distribution and let n2j (j = 1, 2) be some measure of the strength of association between Y and Xj. When n2j is taken to be Pearson’s correlation numerous methods for testing Ho : n21 = n22 have been proposed. However, Pearson’s correlation is not robust and the methods for testing H0 are not level robust in general. This article examines methods for testing H0 based on a robust fit. The first approach assumes a linear model and the second approach uses a nonparametric regression estimator that provides a flexible way of dealing with curvature. The focus is on the Theil-Sen estimator and Cleveland’s LOESS smoother. It is found that a basic percentile bootstrap method avoids Type I errors that exceed the nominal level. However, situations are identified where this approach results in Type I error probabilities well below the nominal level. Adjustments are suggested for dealing with this problem.

Cardiovascular Reponses during Treadmill Exercise in Men with Peripheral Arterial Disease and Intermittent Calf Claudication

Many studies demonstrate higher cardiovascular responses during exercise in subjects with peripheral arterial disease and intermittent claudication (PAD/IC) compared to subjects without PAD/IC. However, the relationship of these variables to exercise intensity is unreported. PURPOSE: To determine the relationships of heart rate (HR), systolic and diastolic pressures (SBP, DBP), and rate-pressure product (RPP) to estimated O2 uptake (EstVO2) during graded treadmill exercise testing in men with PAD/IC and to compare those responses to men without PAD/IC. METHODS: Subjects included 42 men with PAD/IC (mean age 69 yr, BMI 27.1 kg·m2, ankle/brachial index 0.60, B-blocker usage 60%) and 23 men without PAD/IC (mean age 68 yr, BMI 27.3 kg·m2, B-blocker usage 16%). All performed 2 trials of the Gardner treadmill protocol while HR, SBP, DBP and 0-4 pain ratings were monitored continuously with 12-lead ECG and manual sphygmomanometry at 2-min intervals. VO2 was estimated at each test stage based on subjects' body mass and treadmill speed and grade. Mann-Whitney U tests were used to compare regression components between groups. RESULTS: All cardiovascular responses were linearly related to EstVO2 between 0.5 and 2.0 L·min-1. Calf claudication pain ratings increased from 0 (none) to 4 (intolerable) during all treadmill tests in subjects with PAD/IC. Compared to subjects without PAD/IC, median linear regression slopes in subjects with PAD/IC were significantly higher for HR (40 vs. 24 b·min-1, P=.006), SBP (80 vs. 21 mmHg, P<.001), DBP (12 vs. -3 mmHg, P<.001), and RPP (162·10-2 vs. 56·10-2, P<.001). In subjects with PAD/IC, median Y-intercepts were significantly lower for SBP (97 vs. 114 mmHg, P=.001), DBP (66 vs. 74 mmHg, P=.009), and RPP (43·10-2 vs. 73·10-2, P=.001), and the median standard errors of estimate were significantly higher (P<.05) for SBP (472 vs. 283 mmHg, P=.018). CONCLUSION: Compared to men without PAD/IC, cardiovascular responses in men with PAD/IC increased at a faster rate and tended to be more variable during progressive treadmill testing. Differences between groups are likely attributable to claudication pain, multiple comorbidities, metabolic abnormalities, and physical inactivity common in PAD/IC subjects. Supported by VA Rehabilitation R&D Service grant A2860R.

Shoulder muscle activation and fatigue during a controlled forceful hand grip task

PurposeReliable electromyographic evaluation of the shoulder in common painful conditions is a major challenge due to a reduced range of movement and pain-related muscle inhibition. This study investigates the use of a hand grip task for the assessment of shoulder muscle activation. MethodsMuscle activity and fatigue for supraspinatus and infraspinatus muscles were measured in 16 healthy controls using fine-wire electrodes during a controlled gripping task at 50% of maximum voluntary contraction, in a standardized sitting and arm position. Changes in muscle activity and fatigue were measured by the time-slope of root mean square amplitude and median frequency, respectively. ResultsA significant positive amplitude slope (p<0.01) was found for both supraspinatus and infraspinatus, indicating that the task resulted in increasing muscle activity. Judging by the median frequency slope, there was no sign of fatigue progression. ConclusionA standardized hand grip task in a neutral position activates key rotator cuff muscles. This might provide a method for electromyographic assessment of shoulder girdle muscles which avoids problems due to pain-related limitation of movement, and might be useful in the development and monitoring of shoulder rehabilitation strategies.