A Technique for Performing Electrical Impedance Myography in the Mouse Hind Limb: Data in Normal and ALS SOD1 G93A Animals

Objective

To test a method for performing electrical impedance myography (EIM) in the mouse hind limb for the assessment of disease status in neuromuscular disease models.

Methods

An impedance measuring device consisting of a frame with electrodes embedded within an acrylic head was developed. The head was rotatable such that data longitudinal and transverse to the major muscle fiber direction could be obtained. EIM measurements were made with this device on 16 healthy mice and 14 amyotrophic lateral sclerosis (ALS) animals. Repeatability was assessed in both groups.

Results

The technique was easy to perform and provided good repeatability in both healthy and ALS animals, with intra-session repeatability (mean ± SEM) of 5% ±1% and 12% ±2%, respectively. Significant differences between healthy and ALS animals were also identified (e.g., longitudinal mean 50 kHz phase was 18±0.6° for the healthy animals and 14±1.0° for the ALS animals, p = 0.0025).

Conclusions

With this simple device, the EIM data obtained is highly repeatable and can differentiate healthy from ALS animals.

Significance

EIM can now be applied to mouse models of neuromuscular disease to assess disease status and the effects of therapy.     

Assessment of daily life physical activities in pulmonary arterial hypertension

Background

In pulmonary arterial hypertension (PAH), the six-minute walk test (6MWT) is believed to be representative of patient''s daily life physical activities (DL_PA). Whether DL_PA are decreased in PAH and whether the 6MWT is representative of patient''s DL_PA remain unknown.

Methods

15 patients with idiopathic PAH (IPAH) and 10 patients with PAH associated with limited systemic sclerosis (PAH-SSc) were matched with 15 healthy control subjects and 10 patients with limited systemic sclerosis without PAH. Each subject completed a 6MWT. The mean number of daily steps and the mean energy expenditure and duration of physical activities >3 METs were assessed with a physical activity monitor for seven consecutive days and used as markers of DL_PA.

Results

The mean number of daily steps and the mean daily energy expenditure and duration of physical activities >3 METs were all reduced in PAH patients compared to their controls (all p<0.05). The mean number of daily steps correlated with the 6MWT distance for both IPAH and PAH-SSc patients (r = 0.76, p<0.01 and r = 0.85, p<0.01), respectively.

Conclusion

DL_PA are decreased in PAH and correlate with the 6MWT distance. Functional exercise capacity may thus be a useful surrogate of DL_PA in PAH.     

Electrophysiologic Biomarkers for Assessing Disease Progression and the Effect of Riluzole in SOD1 G93A ALS Mice

Objective

To compare electrical impedance myography (EIM) 50 kHz phase to weight, motor score, paw grip endurance (PGE), CMAP amplitude, and MUNE for the identification of disease progression and the effect of riluzole in the SOD1 G93A mouse.

Methods

Twenty-three animals received 8 mg/kg/day riluzole in the drinking water starting at 6 weeks of age; 22 animals served as controls. Weight, motor score, PGE, CMAP, MUNE, and EIM were performed weekly to evaluate disease progression.

Results

No difference in clinical disease onset or survival was found between treated and untreated groups. In addition, all methods failed to identify any beneficial effect of riluzole. Thus, data from all animals were combined for additional analyses. Of the 4 parameters, EIM phase showed the earliest change from baseline and the most linear decline throughout the entire measurement period. In addition, EIM phase correlated with PGE, CMAP amplitude, and MUNE (Spearman r = 0.92, 0.90, and 0.72, respectively, p<0.01 for all). The rate of EIM phase decline also correlated with individual animal survival (Spearman r = −0.31, p<0.05).

Conclusions

At this dose, riluzole is ineffective in slowing progression of ALS. However, EIM phase shows early linear declines, supporting its potential as a useful new biomarker for preclinical drug testing.     

Bacterial Load of Pneumococcal Serotypes Correlates with Their Prevalence and Multiple Serotypes Is Associated with Acute Respiratory Infections among Children Less Than 5 Years of Age

Background

Among pneumococcal serotypes, some serotypes are more prevalent in the nasopharynx than others; determining factors for higher prevalence remain to be fully explored. As non-vaccine serotypes have emerged after the introduction of 7-valent conjugate vaccines, study of serotype specific epidemiology is in need. When two or more serotypes co-colonize, they evolve rapidly to defend host''s immune responses; however, a clear association of co-colonization with a clinical outcome is lacking.

Methods

Children less than 5 years old who were admitted to hospital due to acute respiratory infections (ARI) (n = 595) and healthy children (n = 350) were recruited. Carriage of pneumococcus was determined by culture and lytA PCR in the nasopharyngeal samples. Serotype/serogroup detection and its quantification were done by the nanofluidic real time PCR system. Spearman''s correlation and logistic regression were used to examine a correlation of serotype/serogroup specific bacterial load with its prevalence and an association of co-colonization with ARI respectively.

Results

Serotype/serogroup specific bacterial load was correlated with its prevalence, both in ARI cases (Spearman''s rho = 0.44, n = 186; P<0.0001) and healthy children (Spearman''s rho = 0.41, n = 115; P<0.0001). The prevalence of multiple serotypes was more common in ARI cases than in healthy children (18.5% vs 7.1%; aOR 2.92, 95% CI: 1.27–6.71; P = 0.01). The dominant serotype in the co-colonization had a 2 log10 higher bacterial load than the subdominant serotype, both in ARI cases (P<0.001) and healthy children (P<0.05).

Conclusions

High bacterial load in the nasopharynx may help transmit pneumococci among hosts, and increase the chance of successful acquisition and colonization. Co-colonization of multiple serotypes of pneumococci is linked with ARI, which infers the interactions of multiple serotypes may increase their pathogenicity; however, they may compete for growth in number.     

Using Pattern Classification to Measure Adaptation to the Orientation of High Order Aberrations

Background

The image formed by the eye''s optics is blurred by the ocular aberrations, specific to each eye. Recent studies demonstrated that the eye is adapted to the level of blur produced by the high order aberrations (HOA). We examined whether visual coding is also adapted to the orientation of the natural HOA of the eye.

Methods and Findings

Judgments of perceived blur were measured in 5 subjects in a psychophysical procedure inspired by the “Classification Images” technique. Subjects were presented 500 pairs of images, artificially blurred with HOA from 100 real eyes (i.e. different orientations), with total blur level adjusted to match the subject''s natural blur. Subjects selected the image that appeared best focused in each random pair, in a 6-choice ranked response. Images were presented through Adaptive Optics correction of the subject''s aberrations. The images selected as best focused were identified as positive, the other as negative responses. The highest classified positive responses correlated more with the subject''s Point Spread Function, PSF, (r = 0.47 on average) than the negative (r = 0.34) and the difference was significant for all subjects (p<0.02). Using the orientation of the best fitting ellipse of angularly averaged integrated PSF intensities (weighted by the subject''s responses) we found that in 4 subjects the positive PSF response was close to the subject''s natural PSF orientation (within 21 degrees on average) whereas the negative PSF response was almost perpendicularly oriented to the natural PSF (at 76 degrees on average).

Conclusions

The Classification-Images inspired method is very powerful in identifying the internally coded blur of subjects. The consistent bias of the Positive PSFs towards the natural PSF in most subjects indicates that the internal code of blur appears rather specific to each subject''s high order aberrations and reveals that the calibration mechanisms for normalizing blur also operate using orientation cues.     

You Turn Me Cold: Evidence for Temperature Contagion

Introduction

During social interactions, our own physiological responses influence those of others. Synchronization of physiological (and behavioural) responses can facilitate emotional understanding and group coherence through inter-subjectivity. Here we investigate if observing cues indicating a change in another''s body temperature results in a corresponding temperature change in the observer.

Methods

Thirty-six healthy participants (age; 22.9±3.1 yrs) each observed, then rated, eight purpose-made videos (3 min duration) that depicted actors with either their right or left hand in visibly warm (warm videos) or cold water (cold videos). Four control videos with the actors'' hand in front of the water were also shown. Temperature of participant observers'' right and left hands was concurrently measured using a thermistor within a Wheatstone bridge with a theoretical temperature sensitivity of <0.0001°C. Temperature data were analysed in a repeated measures ANOVA (temperature × actor''s hand × observer''s hand).

Results

Participants rated the videos showing hands immersed in cold water as being significantly cooler than hands immersed in warm water, F_(1,34) = 256.67, p<0.001. Participants'' own hands also showed a significant temperature-dependent effect: hands were significantly colder when observing cold vs. warm videos F_(1,34) = 13.83, p = 0.001 with post-hoc t-test demonstrating a significant reduction in participants'' own left (t₍₃₅₎ = −3.54, p = 0.001) and right (t₍₃₅₎ = −2.33, p = 0.026) hand temperature during observation of cold videos but no change to warm videos (p>0.1). There was however no evidence of left-right mirroring of these temperature effects p>0.1). Sensitivity to temperature contagion was also predicted by inter-individual differences in self-report empathy.

Conclusions

We illustrate physiological contagion of temperature in healthy individuals, suggesting that empathetic understanding for primary low-level physiological challenges (as well as more complex emotions) are grounded in somatic simulation.     

Standardized Handwriting to Assess Bradykinesia,Micrographia and Tremor in Parkinson's Disease

Objective

To assess whether standardized handwriting can provide quantitative measures to distinguish patients diagnosed with Parkinson''s disease from age- and gender-matched healthy control participants.

Design

Exploratory study. Pen tip trajectories were recorded during circle, spiral and line drawing and repeated character ‘elelelel’ and sentence writing, performed by Parkinson patients and healthy control participants. Parkinson patients were tested after overnight withdrawal of anti-Parkinsonian medication.

Setting

University Medical Center Groningen, tertiary care, the Netherlands.

Participants

Patients with Parkinson''s disease (n = 10; mean age 69.0 years; 6 male) and healthy controls (n = 10; mean age 68.1 years; 6 male).

Interventions

Not applicable.

Main Outcome Measures

Movement time and velocity to detect bradykinesia and the size of writing to detect micrographia. A rest recording to investigate the presence of a rest-tremor, by frequency analysis.

Results

Mean disease duration in the Parkinson group was 4.4 years and the patients were in modified Hoehn-Yahr stages 1–2.5. In general, Parkinson patients were slower than healthy control participants. Median time per repetition, median velocity and median acceleration of the sentence task and median velocity of the elel task differed significantly between Parkinson patients and healthy control participants (all p<0.0014). Parkinson patients also wrote smaller than healthy control participants and the width of the ‘e’ in the elel task was significantly smaller in Parkinson patients compared to healthy control participants (p<0.0014). A rest-tremor was detected in the three patients who were clinically assessed as having rest-tremor.

Conclusions

This study shows that standardized handwriting can provide objective measures for bradykinesia, tremor and micrographia to distinguish Parkinson patients from healthy control participants.     

A Comparison of Three Electrophysiological Methods for the Assessment of Disease Status in a Mild Spinal Muscular Atrophy Mouse Model

Objectives

There is a need for better, noninvasive quantitative biomarkers for assessing the rate of progression and possible response to therapy in spinal muscular atrophy (SMA). In this study, we compared three electrophysiological measures: compound muscle action potential (CMAP) amplitude, motor unit number estimate (MUNE), and electrical impedance myography (EIM) 50 kHz phase values in a mild mouse model of spinal muscular atrophy, the Smn1^c/c mouse.

Methods

Smn1^c/c mice (N = 11) and wild type (WT) animals (−/−, N = 13) were measured on average triweekly until approximately 1 year of age. Measurements included CMAP, EIM, and MUNE of the gastrocnemius muscle as well as weight and front paw grip strength. At the time of sacrifice at one year, additional analyses were performed on the animals including serum survival motor neuron (SMN) protein levels and muscle fiber size.

Results

Both EIM 50 kHz phase and CMAP showed strong differences between WT and SMA animals (repeated measures 2-way ANOVA, P<0.0001 for both) whereas MUNE did not. Both body weight and EIM showed differences in the trajectory over time (p<0.001 and p = 0.005, respectively). At the time of sacrifice at one year, EIM values correlated to motor neuron counts in the spinal cord and SMN levels across both groups of animals (r = 0.41, p = 0.047 and r = 0.57, p  = 0.003, respectively), while CMAP did not. Motor neuron number in Smn1^c/c mice was not significantly reduced compared to WT animals.

Conclusions

EIM appears sensitive to muscle status in this mild animal model of SMA. The lack of a reduction in MUNE or motor neuron number but reduced EIM and CMAP values support that much of the pathology in these animals is distal to the cell body, likely at the neuromuscular junction or the muscle itself.     

Do Optimal Prognostic Thresholds in Continuous Physiological Variables Really Exist? Analysis of Origin of Apparent Thresholds,with Systematic Review for Peak Oxygen Consumption,Ejection Fraction and BNP

Background

Clinicians are sometimes advised to make decisions using thresholds in measured variables, derived from prognostic studies.

Objectives

We studied why there are conflicting apparently-optimal prognostic thresholds, for example in exercise peak oxygen uptake (pVO₂), ejection fraction (EF), and Brain Natriuretic Peptide (BNP) in heart failure (HF).

Data Sources and Eligibility Criteria

Studies testing pVO₂, EF or BNP prognostic thresholds in heart failure, published between 1990 and 2010, listed on Pubmed.

Methods

First, we examined studies testing pVO₂, EF or BNP prognostic thresholds. Second, we created repeated simulations of 1500 patients to identify whether an apparently-optimal prognostic threshold indicates step change in risk.

Results

33 studies (8946 patients) tested a pVO₂ threshold. 18 found it prognostically significant: the actual reported threshold ranged widely (10–18 ml/kg/min) but was overwhelmingly controlled by the individual study population''s mean pVO₂ (r = 0.86, p<0.00001). In contrast, the 15 negative publications were testing thresholds 199% further from their means (p = 0.0001). Likewise, of 35 EF studies (10220 patients), the thresholds in the 22 positive reports were strongly determined by study means (r = 0.90, p<0.0001). Similarly, in the 19 positives of 20 BNP studies (9725 patients): r = 0.86 (p<0.0001).Second, survival simulations always discovered a “most significant” threshold, even when there was definitely no step change in mortality. With linear increase in risk, the apparently-optimal threshold was always near the sample mean (r = 0.99, p<0.001).

Limitations

This study cannot report the best threshold for any of these variables; instead it explains how common clinical research procedures routinely produce false thresholds.

Key Findings

First, shifting (and/or disappearance) of an apparently-optimal prognostic threshold is strongly determined by studies'' average pVO₂, EF or BNP. Second, apparently-optimal thresholds always appear, even with no step in prognosis.

Conclusions

Emphatic therapeutic guidance based on thresholds from observational studies may be ill-founded. We should not assume that optimal thresholds, or any thresholds, exist.     

A Study of Remitted and Treatment-Resistant Depression Using MMPI and Including Pessimism and Optimism Scales

Background

The psychological aspects of treatment-resistant and remitted depression are not well documented.

Methods

We administered the Minnesota Multiphasic Personality Inventory (MMPI) to patients with treatment-resistant depression (n = 34), remitted depression (n = 25), acute depression (n = 21), and healthy controls (n = 64). Pessimism and optimism were also evaluated by MMPI.

Results

ANOVA and post-hoc tests demonstrated that patients with treatment-resistant and acute depression showed similarly high scores for frequent scale (F), hypochondriasis, depression, conversion hysteria, psychopathic device, paranoia, psychasthenia and schizophrenia on the MMPI compared with normal controls. Patients with treatment-resistant depression, but not acute depression registered high on the scale for cannot say answer. Using Student''s t-test, patients with remitted depression registered higher on depression and social introversion scales, compared with normal controls. For pessimism and optimism, patients with treatment-resistant depression demonstrated similar changes to acutely depressed patients. Remitted depression patients showed lower optimism than normal controls by Student''s t-test, even though these patients were deemed recovered from depression using HAM-D.

Conclusions

The patients with remitted depression and treatment-resistant depression showed subtle alterations on the MMPI, which may explain the hidden psychological features in these cohorts.     

Simple Estimation of Incident HIV Infection Rates in Notification Cohorts Based on Window Periods of Algorithms for Evaluation of Line-Immunoassay Result Patterns

Background

Tests for recent infections (TRIs) are important for HIV surveillance. We have shown that a patient''s antibody pattern in a confirmatory line immunoassay (Inno-Lia) also yields information on time since infection. We have published algorithms which, with a certain sensitivity and specificity, distinguish between incident (< = 12 months) and older infection. In order to use these algorithms like other TRIs, i.e., based on their windows, we now determined their window periods.

Methods

We classified Inno-Lia results of 527 treatment-naïve patients with HIV-1 infection < = 12 months according to incidence by 25 algorithms. The time after which all infections were ruled older, i.e. the algorithm''s window, was determined by linear regression of the proportion ruled incident in dependence of time since infection. Window-based incident infection rates (IIR) were determined utilizing the relationship ‘Prevalence  =  Incidence x Duration’ in four annual cohorts of HIV-1 notifications. Results were compared to performance-based IIR also derived from Inno-Lia results, but utilizing the relationship ‘incident  =  true incident + false incident’ and also to the IIR derived from the BED incidence assay.

Results

Window periods varied between 45.8 and 130.1 days and correlated well with the algorithms'' diagnostic sensitivity (R² = 0.962; P<0.0001). Among the 25 algorithms, the mean window-based IIR among the 748 notifications of 2005/06 was 0.457 compared to 0.453 obtained for performance-based IIR with a model not correcting for selection bias. Evaluation of BED results using a window of 153 days yielded an IIR of 0.669. Window-based IIR and performance-based IIR increased by 22.4% and respectively 30.6% in 2008, while 2009 and 2010 showed a return to baseline for both methods.

Conclusions

IIR estimations by window- and performance-based evaluations of Inno-Lia algorithm results were similar and can be used together to assess IIR changes between annual HIV notification cohorts.     

Plasma Levels of Soluble Urokinase-Type Plasminogen Activator Receptor Associate with the Clinical Severity of Acute Puumala Hantavirus Infection

Objectives

Urokinase-type plasminogen activator receptor is a multifunctional glycoprotein, the expression of which is increased during inflammation. It is known to bind to β₃-integrins, which are elementary for the cellular entry of hantaviruses. Plasma soluble form of the receptor (suPAR) levels were evaluated as a predictor of severe Puumala hantavirus (PUUV) infection and as a possible factor involved in the pathogenesis of the disease.

Design

A single-centre prospective cohort study.

Subjects and Methods

Plasma suPAR levels were measured twice during the acute phase and once during the convalescence in 97 patients with serologically confirmed acute PUUV infection using a commercial enzyme-linked immunosorbent assay (ELISA).

Results

The plasma suPAR levels were significantly higher during the acute phase compared to the control values after the hospitalization (median 8.7 ng/ml, range 4.0–18.2 ng/ml vs. median 4.7 ng/ml, range 2.4–12.2 ng/ml, P<0.001). The maximum suPAR levels correlated with several variables reflecting the severity of the disease. There was a positive correlation with maximum leukocyte count (r = 0.475, p<0.001), maximum plasma creatinine concentration (r = 0.378, p<0.001), change in weight during the hospitalization (r = 0.406, p<0.001) and the length of hospitalization (r = 0.325, p = 0.001), and an inverse correlation with minimum platelet count (r = −0.325, p = 0.001) and minimum hematocrit (r = −0.369, p<0.001).

Conclusion

Plasma suPAR values are markedly increased during acute PUUV infection and associate with the severity of the disease. The overexpression of suPAR possibly activates β₃-integrin in PUUV infection, and thus might be involved in the pathogenesis of the disease.     

KCNE1 rs1805127 Polymorphism Increases the Risk of Atrial Fibrillation: A Meta-Analysis of 10 Studies

Background

Atrial fibrillation (AF) is one of the most common types of arrhythmia in humans. Recently, many studies have investigated the relationship between human atrial fibrillation and the single nucleotide polymorphism (SNP) of rs1805127 (A>G) in KCNE1 gene, but the results were still inconsistent and inconclusive.

Method

Electronic databases and bibliographies of retrieved studies were searched. We performed a meta-analysis of ten case-control studies, including 2099 cases and 2252 controls, to evaluate the association of rs1805127 polymorphism (A>G) with the risk of AF. Random-effects model was used when the heterogeneity was obvious; otherwise, fixed-effects model was applied. Meta-regression was performed to examine potential source of heterogeneity. Egger''s test and Begg''s test were used to detect publication biases.

Results

The results showed a significantly increased risk of AF in homozygote comparison (GG vs. AA:OR = 1.899, 95%CI: 1.568, 2.300; P_{heterogeneity} = 0.217), heterozygote comparison (GA vs. AA:OR = 1.436, 95% CI:1.190, 1.732; P_{heterogeneity} = 0.739), dominant model(GA /GG vs. AA: OR = 1.624, 95%CI: 1.361, 1.938; P_{heterogeneity} = 0.778) and recessive model (GG vs. GA/AA: OR = 1.394, 95%CI:1.152, 1.686; P_{heterogeneity} = 0.03). Meta-regression revealed that the sample size and the types of AF were the source of the heterogeneity.

Conclusion

The rs1805127 polymorphism (A>G) of KCNE1 is associated with an increased risk of AF, which suggests the rs1805217 polymorphism of KCNE1 gene may play an important role in the pathogenesis of AF.     

Ventilation/Perfusion Scintigraphy in Children with Post-Infectious Bronchiolitis Obliterans: A Pilot Study

Purpose

Childhood post-infectious bronchiolitis obliterans (BO) is an infrequent lung disease leading to narrowing and/or complete obliteration of small airways. Ventilation and perfusion (V/Q) scan can provide both regional and global pulmonary information. However, only few retrospective researches investigating post-infectious BO involved V/Q scan, the clinical value of this method is unknown. This preliminary prospective study was aimed to evaluate the correlation of V/Q scan with disease severity, pulmonary function test results, and prognosis in children with post-infectious BO.

Methods

Twenty-five post-infectious BO children (18 boys and 7 girls; mean age, 41 months) underwent V/Q scan and pulmonary function tests. Patients were followed after their inclusion. Ventilation index and perfusion index obtained from V/Q scan were used to measure pulmonary abnormalities. Spearman''s rank correlation test of ventilation index and perfusion index on disease severity, lung function tests indices, and follow-up results were performed.

Results

The median follow-up period was 4.6 years (range, 2.2 to 5.0 years). Ventilation index and perfusion index were both correlated with disease severity (r = 0.72, p<0.01 and r = 0.73, p<0.01), but only ventilation index was related to pulmonary function tests results (all p<0.05). In addition, Spearman test yielded significant correlations between perfusion index and prognosis (r = 0.77, p<0.01), and ventilation index and prognosis (r = 0.63, p = 0.01).

Conclusions

For children with post-infectious BO, the present study preliminarily indicated that the degree of ventilation and perfusion abnormalities evaluated by V/Q scan may be used to assess disease severity, and may be predictive of patient''s outcome.     

Serum Cytokeratin 19 Fragment,CK19-2G2, as a Newly Identified Biomarker for Lung Cancer

Background

CK19-2G2, a new fragment of cytokeratin 19, is a potential tumor marker for diagnosing lung cancer. The preoperative level of serum CK19-2G2 has been demonstrated to be associated with tumor metastasis and survival of breast cancer patients. This study investigated the postoperative dynamic changes in serum CK19-2G2 levels and its clinical significance in lung cancer patients.

Materials and Methods

Preoperative serum CK19-2G2 levels were measured in 630 lung cancer patients and were compared with individuals with benign pulmonary diseases (n = 134) and healthy volunteers (n = 263). In 352 cases, the patients underwent surgery. In these patients, in addition to preoperative assays, serum CK19-2G2 was also monitored at 1 week and 1 month after the operation.

Results

The preoperative baseline levels of serum CK19-2G2 was significantly higher in lung cancer patients than patients with benign diseases and healthy controls (P<0.001). The postoperative levels of CK19-2G2 declined significantly within 1 week after tumor resection. Hereafter, a further decrease was observed in the patients who underwent palliative operations, while for the patients in the radical resection group, their CK19-2G2 levels stabilized.

Conclusion

CK19-2G2 may be a candidate marker for diagnosing and monitoring a patient''s response to lung cancer treatment. In addition, CK19-2G2 may be an indicator for micrometastases in lung cancer patients.     

Evaluation of Anterior Segment Parameters and Possible Influencing Factors in Normal Subjects Using a Dual Scheimpflug Analyzer

Purpose

To investigate normal anterior segment parameters and analyze the possible influencing factors using a dual Scheimpflug system.

Setting

Department of Ophthalmology, Affiliated Sixth People''s Hospital Shanghai Jiao Tong University, Shanghai, China.

Design

A prospective observational case series.

Methods

A total of 153 normal subjects (153 eyes) were studied. The anterior segment parameters, including the central corneal thickness (CCT), anterior chamber depth (ACD), pupil diameter (PD), keratoconus prediction index (KPI), simulated keratometry (SimK) values, anterior instantaneous curvature (AIC), posterior axial curvature (PAC), corneal eccentricity, total corneal power (TCP), axial curvature (AC), total corneal wavefront (TCW), high order aberration (HOA), and spherical aberration (SA), were determined using a dual Scheimpflug analyzer.

Results

The CCT and ACD were both negatively correlated with age (r = −0.203, p = 0.012; r = −0.589, p<0.001). There was no significant difference in the refractive indices of AIC and SimK. Compared with the negative correlation of HOA and SA (r = −0.358, p<0.001), a positive correlation was found between TCW and HOA (r = 0.561, p<0.001). Unlike the decreased tendency of AC, the TCP increased gradually from the center to the periphery in the central 8 mm diameter. TCP showed a significant correlation with AC in the analyzed area.

Conclusions

AIC and SimK provide different information in clinic, but the refractive indices of them showed no difference in this healthy study population, and age should be considered when using CCT and ACD values.     

Objective Determination of Optimal Number of Spectral-Domain Optical Coherence Tomographic Images of Retina to Average

Purpose

To determine by objective methods the minimum number of spectral-domain optical coherence tomographic (SD-OCT) images to average to obtain the clearest retinal image.

Methods

SD-OCT Images were obtained from 9 healthy eyes and also from a phantom eye model. The SD-OCT images were obtained by averaging 1, 5, 20, 60, and 100 B-scan images. The reflectivity (mean gray value) of the different retinal layers was evaluated in these images. The image quality was evaluated by the size of the standard deviations (SDs) and the contrast-to-noise ratios (CNRs). A phantom eye model made by TiO₂ silicone plates was also examined.

Results

The SDs decreased significantly when the number of images averaged increased from 1 to 5 and also from 5 to 20 (P<0.05, post hoc Tukey''s honestly significant difference tests). The SD of the automatic real time averaging of 1 (ART = 1) and ART = 5 were significantly larger than the SD of ART = 100 (P<0.05). The SDs of all other averaged numbers were not significantly larger than that of ART = 100. The CNR increased with an increase in the number of images averaged, and there was a significant increase between ART = 1 to 5 and between ART = 5 to 20 (P<0.05). No significant differences in the CNR was observed between ART = 5, ART = 20 and ART = 60. Similar results were obtained with the phantom eye model.

Conclusions

Although the image quality of the SD-OCT images of the retina improved with an increase in the number of images averaged, it does not improve significantly by averaging more than 20 images.     

The Impact of Stressful Life Events on Excessive Alcohol Consumption in the French Population: Findings from the GAZEL Cohort Study

Background

Major life changes may play a causative role in health through lifestyle factors, such as alcohol. The objective was to examine the impact of stressful life events on heavy alcohol consumption among French adults.

Methods

Trajectories of excessive alcohol consumption in 20,625 employees of the French national gas and electricity company for up to 5 years before and 5 years after an event, with annual measurements from 1992. We used repeated measures analysis of time series data indexed to events, employing generalized estimating equations.

Results

For women, excessive alcohol use increased before important purchase (p = 0.021), children leaving home (p<0.001), and death of loved ones (p = 0.03), and decreased before widowhood (p = 0.015); in the year straddling the event, increased consumption was observed for important purchase (p = 0.018) and retirement (p = 0.002); at the time of the event, consumption decreased for marriage (p = 0.002), divorce, widowhood, and death of loved one (all p<0.001), and increased for retirement (p = 0.035). For men, heavy alcohol consumption increased in the years up to and surrounding the death of loved ones, retirement, and important purchase (all p<0.001), and decreased after (all p<0.001, except death of loved one: p = 0.006); at the time of the event, consumption decreased for all events except for children leaving home and retirement, where we observed an increase (all p<0.001). For women and men, heavy alcohol consumption decreased prior to marriage and divorce and increased after (all p<0.001, except for women and marriage: p = 0.01).

Conclusion

Stressful life events promote healthy and unhealthy alcohol consumption. Certain events impact alcohol intake temporarily while others have longer-term implications. Research should disentangle women''s and men''s distinct perceptions of events over time.     

Proximal Tubule Dysfunction Is Associated with Podocyte Damage Biomarkers Nephrin and Vascular Endothelial Growth Factor in Type 2 Diabetes Mellitus Patients: A Cross-Sectional Study

Background

There is an ongoing debate as to whether early diabetic nephropathy in Type 2 diabetes mellitus may be attributed to the glomerulus or to the proximal tubule. Urinary excretion of nephrin and vascular endothelial growth factor may increase even in the normoalbuminuria stage. In the course of diabetic nephropathy, the proximal tubule may be involved in the uptake of urinary nephrin and vascular endothelial growth factor.

Materials and Methods

Two groups of consecutive Type 2 diabetes mellitus outpatients (38 normo-, 32 microalbuminuric) and 21 healthy subjects were enrolled in a cross-sectional study and evaluated concerning the relation of proximal tubule dysfunction with the podocyte biomarkers excretion, assessed by ELISA methods. The impact of advanced glycation end-products on this relation was also queried.

Results

Urinary alpha₁-microglobulin and kidney injury molecule-1 correlated with urinary albumin:creatinine ratio (R² = 0.269; p<0.001; R² = 0.125; p<0.001), nephrinuria (R² = 0.529; p<0.001; R² = 0.203; p<0.001), urinary vascular endothelial growth factor (R² = 0.709; p<0.001; R² = 0.360; p<0.001), urinary advanced glycation end-products (R² = 0.578; p<0.001; R² = 0.405; p<0.001), serum cystatin C (R² = 0.130; p<0.001; R² = 0.128; p<0.001), and glomerular filtration rate (R² = 0.167; p<0.001; R² = 0.166; p<0.001); nephrinuria and urinary vascular endothelial growth factor correlated with urinary albumin:creatinine ratio (R² = 0.498; p<0.001; R² = 0.227; p<0.001), urinary advanced glycation end-products (R² = 0.251; p<0.001; R² = 0.308; p<0.001), serum cystatin C (R² = 0.157; p<0.001; R² = 0.226; p<0.001), and glomerular filtration rate (R² = 0.087; p = 0.007; R² = 0.218; p<0.001).

Conclusions

In Type 2 diabetes mellitus there is an association of proximal tubule dysfunction with podocyte damage biomarkers, even in the normoalbuminuria stage. This observation suggests a potential role of the proximal tubule in urinary nephrin and urinary vascular endothelial growth factor processing in early diabetic nephropathy, a fact which could be related to advanced glycation end-products intervention. Podocyte damage and proximal tubule dysfunction biomarkers could be validated as a practical approach to the diagnosis of early diabetic nephropathy by further studies on larger cohorts.