Intra-individual Difference Research Articles

UV-light and dietary vitamin D and their effects on ionized calcium and 25-OH-D plasma concentrations in captive gentoo penguins (Pygoscelis papua).

In this study, the effect of ultraviolet (UV) light and dietary vitamin D on calcium metabolism in permanently indoor-housed gentoo penguins (Pygoscelis papua) was investigated. The study consisted of three periods, each completed with blood samples to analyse plasma concentrations of 25-OH-D, 1,25-(OH)2 -D, ionized (iCa) and total calcium (tCa). During the first study period (D), animals were housed under routine conditions without UV-light and fed a diet of different fish species, supplemented with 1,000IU vitamin D per animal and day. The following study period (Baseline) of 28-day duration consisted of the same diet without any vitamin D supplementation and without UV-light. During the study period (UVB) artificial UV-light was added for 3weeks. The vitamin D content of fish was measured by high-performance liquid chromatography. It varied between fish species and between facilities, ranging from no measurable content in capelin (Mallotus villosus) to 7,340IU vitamin D/kg original matter (OM) in herring (Clupea spp). The average dietary vitamin D content was 311IU/kg OM at facility 1 and 6,325IU/kg OM at facility 2, resulting in a vitamin D intake per animal and day without supplementation of 130IU (25.5IU/kg body weight BW) and 2,454IU (438.2IU/kg BW) respectively. The supplementation of vitamin D elevated significantly the plasma concentrations of 25-OH-D by an intraindividual difference of 15 (range -2 to 59)nmol/L and tCa by 0.1 (0.0-0.3) mmol/L only at facility 2. The exposure to UV-light raised the blood concentrations of tCa at facility 2 by 0.15 (0.1-0.2) mmol/L, and of iCa and tCa for females at facility 1 by 0.23 (0.13-0.41) mmol/L and 1.8 (1.1-2.5) mmol/L respectively. No significant influence of the study periods (D) and (UVB) was found for the concentrations of 1,25-(OH)2 -D at both facilities.

Modified breath-hold compressed-sensing 3D MR cholangiopancreatography with a small field-of-view and high resolution acquisition: Clinical feasibility in biliary and pancreatic disorders.

Compressed-sensing (CS) accelerated 3D MR cholangiopancreatography (MRCP) could be acquired in both navigator-triggered (NT) and breath-hold (BH) mode, but the latter has been considered inferior in depicting pancreatic duct and diagnosing pancreatic duct-related diseases. To prospectively evaluate the clinical feasibility of a modified 3D BH-CS-MRCP prototype protocol with small field-of-view (FOV) and higher spatial resolution, and to compare its performance to the original BH-CS-MRCP and NT-CS-MRCP. Prospective cohort study. Eighty-two patients with suspected pancreaticobiliary diseases (46 male, median age, 55 years, range, 16-79 years), including seven noncooperative patients. 3T, CS-MRCP. Three protocols were performed in random order in each patient. Acquisition time of each protocol was recorded. Image quality, background suppression, duct visibility, and diagnostic confidence with duct anatomic variations and duct-related pathologies were rated on a 5-point scale by two blinded radiologists independently. The Wilcoxon signed-rank test was used to compare the intraindividual difference. Interobserver agreement was determined using kappa coefficients. The diagnostic performance was calculated using receiver operating characteristic curves. Acquisition time was 17 seconds for both BH-CS-MRCP protocols, and 127.5 ± 36.9 seconds for NT-CS-MRCP. In 75 cooperative patients, the incidence of major artifacts was low for all protocols (5.3-8.0%). Background suppression was similar with the two BH-CS-MRCP protocols (3.67 ± 0.77 for original BH-CS-MRCP and 3.70 ± 0. 57 for modified BH-CS-MRCP, respectively), both inferior to the NT-CS-MRCP protocol (4.41 ± 0.68, P < 0.001 for both). Modified BH-CS-MRCP and NT-CS-MRCP depicted pancreatic duct and second-level branches of biliary duct better than original BH-CS-MRCP (all P < 0.01). The diagnostic performance for detecting bile duct abnormalities was similar for all protocols (P = 0.53-0.87), whereas for detecting pancreatic duct abnormalities, modified BH-CS-MRCP and NT-CS-MRCP had significantly better performance compared to original BH-CS-MRCP (both P < 0.01). In seven noncooperative patients, NT-CS-MRCP had superior image quality than both BH protocols (both P < 0.01). Modified BH-CS-MRCP is feasible for pancreatic and biliary disorders. NT-CS-MRCP might be more useful in noncooperative patients. 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1389-1399.

Physiologic distribution of PSMA-ligand in salivary glands and seromucous glands of the head and neck on PET/CT

Prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) is used for detection and (re)staging of prostate cancer. However, healthy salivary, seromucous, and lacrimal glands also have high PSMA-ligand uptake. This study aimed to describe physiologic PSMA-ligand uptake distribution characteristics in the head and neck to aid in PSMA PET/CT interpretation and to identify possible new clinical applications for PSMA-ligand imaging. Thirty consecutive patients who underwent PSMA PET/CT for prostate cancer were evaluated. Tracer maximum standardized uptake values (SUVmax) in the salivary, seromucous, and lacrimal glands were determined visually and quantitatively. Overall and intraindividual variations were reported. All gland locations had increased tracer uptake. The mean SUVmax ± standard deviation varied: parotid 12.3 ± 3.9; submandibular 11.7 ± 3.5; sublingual 4.5 ± 1.9; soft palate 2.4 ± 0.5; pharyngeal wall 4.3 ± 1.3; nasal mucosa 3.4 ± 0.9; supraglottic larynx 2.7 ± 0.7; and lacrimal 6.2 ± 2.2. The parotid had the largest overall variation in SUVmax (5.2-22.9), and the sublingual glands had the largest mean intraindividual difference (18.1%). Major and minor salivary and seromucous glands consistently have high PSMA-ligand uptake. Minor gland locations can be selectively visualized by this technique for the first time. This provides potential new applications such as quantification of present salivary gland tissues and individualization of radiotherapy for head and neck cancer or lutetium-177-PSMA radionuclide treatment.

Changes in water manganese levels and longitudinal assessment of intellectual function in children exposed through drinking water

BackgroundManganese is commonly found in water but potential neurotoxic effects from exposure through drinking water are poorly understood. We previously reported a cross-sectional study showing that drinking water Mn concentration was associated with lower IQ in children aged 6 to 13 years. ObjectiveFor this follow-up study, we aimed to re-assess the relation between exposure to Mn from drinking water and IQ at adolescence. In addition, we aimed to examine whether changes in drinking water Mn concentration was associated with changes in IQ scores. MethodsFrom the 380 children enrolled in the baseline study, 287 participated to this follow-up study conducted in average 4.4 years after. Mn concentration was measured in home tap water and children's hair. The relationships between these Mn exposure indicators and IQ scores (Weschsler Abbreviated Scale of Intelligence) at follow-up were assessed with linear regression analysis, adjusting for potential confounders. Intra-individual differences in IQ scores between the two examinations were compared for children whose Mn concentration in water remained stable between examinations, increased or decreased. ResultsThe mean age at follow-up was 13.7 years (range, 10.5 to 18.0 years). Geometric mean of Mn concentration in water at follow-up was 14.5μg/L. Higher Mn concentration in water measured at follow-up was associated with lower Performance IQ in girls (β for a 10-fold increase=−2.8, 95% confidence intervals [CI] −4.8 to −0.8) and higher Performance IQ in boys (β=3.9, 95% CI 1.4 to 6.4). IQ scores were not significantly associated with Mn concentration in hair, although similar trends as for concentration in water were observed. For children whose Mn concentration in water increased between baseline and follow-up, Performance IQ scores decreased significantly (intra-individual difference, −2.4 points). ConclusionHigher levels of Mn in drinking water were associated with lower Performance IQ in girls, whereas the opposite was observed in boys. These findings suggest long-term exposure to Mn through drinking water is associated differently with cognition in boys and girls.

Reproducibility of the plasma glucose response to moderate-intensity exercise in adolescents with Type 1 diabetes.

The aim of the study was to evaluate the reproducibility of the plasma glucose response to moderate-intensity exercise performed on different days under controlled conditions in adolescents with Type 1 diabetes. Eight adolescents with Type 1 diabetes on continuous subcutaneous insulin infusion completed two exercise sessions, each on two separate days, under basal insulin and fasting conditions. On each day, participants cycled twice for 30 min at 55% of their peak rate of oxygen consumption, with each exercise session separated by a 30-min rest. Plasma insulin levels were similar between testing days and exercise sessions. The mean absolute drop in plasma glucose from the commencement to the end of exercise was 1.6 ± 0.5 mmol/l on day 1 and 1.9 ± 0.7 mmol/l on day 2 (P = 0.3). In response to the first exercise session, plasma glucose levels relative to baseline did not change significantly (0.2 ± 0.6 and -0.2 ± 0.5 mmol/l on days 1 and 2). By contrast, the change in plasma glucose during the second exercise session was -1.1 ± 0.7 and -1.3 ± 0.7mmol/l on days 1 and 2, respectively. The mean absolute intra-individual difference in the change in plasma glucose between testing days were 0.7 ± 0.5 [95% confidence interval (CI) 0.4-1.0] and 0.7 ± 0.4 (95% CI 0.4-1.0) mmol/l, at the end of the first and second exercise sessions respectively. The plasma glucose response to moderate-intensity exercise under similar glycaemic and basal insulin conditions can be reproducible in adolescents with Type 1 diabetes.

Accelerated re-epithelialization of partial-thickness skin wounds by a topical betulin gel: Results of a randomized phase III clinical trials program

The clinical significance of timely re-epithelialization is obvious in burn care, since delayed wound closure is enhancing the risk of wound site infection and extensive scarring. Topical treatments that accelerate wound healing are urgently needed to reduce these sequelae. Evidence from preliminary studies suggests that betulin can accelerate the healing of different types of wounds, including second degree burns and split-thickness skin graft wounds.The goal of this combined study program consisting of two randomized phase III clinical trials in parallel is to evaluate whether a topical betulin gel (TBG) is accelerating re-epithelialization of split-thickness skin graft (STSG) donor site wounds compared to standard of care.Two parallel blindly evaluated, randomised, controlled, multicentre phase III clinical trials were performed in adults undergoing STSG surgery (EudraCT nos. 2012-003390-26 and 2012-000777-23). Donor site wounds were split into two equal halves and randomized 1:1 to standard of care (a non-adhesive moist wound dressing) or standard of care plus TBG consisting of 10% birch bark extract and 90% sunflower oil (Episalvan, Birken AG, Niefern-Oeschelbronn, Germany). The primary efficacy assessment was the intra-individual difference in time to wound closure assessed from digital photographs by three blinded experts.A total of 219 patients were included and treated in the two trials. Wounds closed faster with TBG than without it (15.3 vs. 16.5 days; mean intra-individual difference=−1.1 days [95% CI, −1.5 to −0.7]; p<0.0001).This agreed with unblinded direct clinical assessment (difference=−2.1 days [95% CI, −2.7 to −1.5]; p<0.0001). Adverse events possibly related to treatment were mild or moderate and mostly at the application site.TBG accelerates re-epithelialization of partial thickness wounds compared to the current standard of care, providing a well-tolerated contribution to burn care in practice.

A combined "in vivo" noninvasive evaluation of carotid plaques using ultrasonography and high-resolution magnetic resonance - new insight into plaque burden and vulnerability.

Qualitative change in carotid plaques was prospectively evaluated by Gray Scale Median (GSM) analysis at repeated examinations "in vivo", in relation to quantitative change in carotid arterial geometry, as assessed by high-resolution magnetic resonance imaging (HR-MRI). Duplex ultrasound with GSM analysis and HR-MRI at the carotid level were performed at baseline and 1- and 2-year follow up in 30 patients with < 70% carotid stenosis. Changes in GSM values (ΔGSM) were evaluated as the intra-individual difference between 2-year and baseline values. HR-MRI studies were evaluated for lumen area (LA), total vessel area (TVA), vessel wall area (VWA = TVA-LA) and normalized wall index (NWI = VWA/TVA). ΔGSM value distribution was divided into quartiles. Predominantly echolucent plaques with ΔGSM value in the lowest quartile (ΔGSM ≤- 8) showed a significantly greater mean 2-year LA (28.62 ± 10.9 mm2 vs. 17.88 ± 4.8 mm2, p = 0.04) and a greater mean 2-year TVA (83.64 ± 19.4 mm2 vs. 63.26 ± 9.2 mm2, p = 0.02) than predominantly echogenic plaques with ΔGSM value in the highest quartile (ΔGSM ≥8). Increasing echolucency during the 2-year follow up was associated with a 2-year lower degree of stenosis and higher tendency toward lumen preservation. By corroborating that plaque vulnerability is highly independent of stenosis severity, our study provided a possible new combined "in vivo" noninvasive approach for the assessment of carotid plaque vulnerability.

Preanalytical effects on biochemical results for medical decisions in urea cycle defects

Reliable biochemical results are needed for the diagnosis and follow-up of patients with hyperammonemic disorders. Preanalytical factors influence the results and can lead to erroneous interpretations and medical decisions. I emphasize the need of quality assessment in the laboratory, of adequate time of sampling for ammonia and amino acid analyses after food intake in urea cycle disorders and on the rational estimation whether the intra-individual difference between two sequential results of an analyte is solely due to analytical variance or not. I present arguments for banning capillary blood samples as well as whole blood samples collected on filter paper for confirming or excluding a suspected diagnosis or for controlling data in the follow-up of a disease or its therapy.

1B12 口腔インプラント科登院実習における骨質と力覚の教育

To meet the requirement for the new educational system in oral implantology at dental colleges that is expected to reduce the number of medical accidents in oral implant surgery, a new force sensing device for drilling the mandibular trabecular bone has been developed. The drilling force was calculated by stochastic multiscale finite element method based on the micro-CT images of cadavers. Not only the inter-individual difference but also the intra-individual difference, which means the variation of drilling force in the trabecular bone region, has been considered by the micro-CT image-based analyses. The multiscale method could analyze the anisotropic nature of the trabecular bone. Hence, the drilling in different angle results in different drilling force. The inter- and intra-individual differences and the consideration of anisotropy are essential in the education of bone quality. The calculated drilling force was implemented in the force sensing device that can control the drilling speed reflecting the input force. The developed system was used in the problem based learning (PBL) class at Tokyo Dental College. The result of the force sensing by students is reported, which supports the usefulness of the developed system.

Prefrontal and Striatal Glutamate Differently Relate to Striatal Dopamine: Potential Regulatory Mechanisms of Striatal Presynaptic Dopamine Function?

The present work demonstrates complementary relationships between prefrontal and striatal glutamate and ventral striatal presynaptic dopamine using human imaging measures: a negative correlation between prefrontal glutamate and presynaptic dopamine and a positive relationship between striatal glutamate and presynaptic dopamine are revealed. The results may reflect a regulatory role of prefrontal and striatal glutamate for ventral striatal presynaptic dopamine levels. Such glutamate-dopamine relationships improve our understanding of neurochemical interactions in prefrontostriatal circuits and have implications for the neurobiology of mental disease.

Rotational alignment of the distal femur: anthropometric measurements with CT-based patient-specific instruments planning show high variability of the posterior condylar angle.

Finding the anatomical landmarks used for correct femoral axial alignment can be difficult. The posterior condylar line (PCL) is probably the easiest to find during surgery. The aim of this study was to analyse whether a predetermined fixed angle referencing of the PCL could help find the surgical epicondylar axis (SEA) and this based on a large CT database with enough Caucasian diversity to be representable. A total of 2,637 CT scans and 3D reconstructions from patients on four continents, executed for preoperative planning and creation of patient-specific instrumentation, were used to perform anthropometric measurements and to measure the posterior condylar angle (PCA) between the surgical epicondylar angle and the PCL. The mean (SD) PCA was 4° (1.4°) of external rotation. A significant correlation was found between more external rotation of the SEA and more proximal varus of the tibia or more distal valgus of the femur. For 59% of the study population, 4° external rotation from the PCL would be the right amount of axial rotation to align the femoral component in line with the SEA. Nine per cent needs less, and 32% needs more than 4° of axial rotation. On 105 (4%) CT-based 3D models, external rotation between 7° and 11° was measured and 77 (73%) of those cases were in varus or neutral alignment. In 132 patients, bilateral measurements were available and 94 (71%) had rotation within 1° of the opposite side. This last finding underlines that there is even an intra-individual difference in distal femoral anatomy that can range from 1° to 5°. This study was performed on a very large anthropometric CT and 3D models database and showed that there is a 41% risk of malalignment if a fixed PCA referenced of the PCL is used in total knee arthroplasty. The clinical importance of this study is the observation that femoral axial anatomy is individual and also that it is determined by the tibial anatomy. A group of patients needs more than the average external rotation because they have more distal femoral valgus with dysplastic condyles or more proximal tibial varus with a bigger medial condyle. III.

Software-assisted quantitative analysis of small bowel motility compared to manual measurements

To validate a newly developed software prototype that automatically analyses small bowel motility by comparing it directly with manual measurement. Forty-five patients with clinical indication for small bowel magnetic resonance imaging (MRI) were retrospectively included in this institutional review board-approved study. MRI was performed using a 1.5 T system following a standard MR-enterography protocol. Small bowel motility parameters (contractions-per-minute, luminal diameter, amplitude) were measured three times each in identical segments using the manual and the semiautomatic software-assisted method. The methods were compared for agreement, repeatability, and time needed for each measurement. All parameters were compared between the methods. A total of 91 small-bowel segments were analysed. No significant intra-individual difference (p > 0.05) was found for peristaltic frequencies between the methods (mean: 4.14/min manual; 4.22/min software-assisted). Amplitudes (5.14 mm; 5.57 mm) and mean lumen diameters (17.39 mm; 14.68) differed due to systematic differences in the definition of the bowel wall. Mean duration of single measurement was significantly (p < 0.01) shorter with the software (6.25 min; 1.30 min). The scattering of repeated measurements was significantly (p < 0.05) lower using the software. The software-assisted method accomplished highly reliable, fast and accurate measurement of small bowel motility. Measurement precision and duration differed significantly between the two methods in favour of the software-assisted technique.

Influence of Platform Switching on Bone-level Alterations

The concept of platform switching has been introduced to implant dentistry based on clinical observations of reduced peri-implant crestal bone loss. However, published data are controversial, and most studies are limited to 12 months. The aim of the present randomized clinical trial was to test the hypothesis that platform switching has a positive impact on crestal bone-level changes after 3 years. Two implants with a diameter of 4 mm were inserted crestally in the posterior mandible of 25 patients. The intraindividual allocation of platform switching (3.3-mm platform) and the standard implant (4-mm platform) was randomized. After 3 months of submerged healing, single-tooth crowns were cemented. Patients were followed up at short intervals for monitoring of healing and oral hygiene. Statistical analysis for the influence of time and platform type on bone levels employed the Brunner-Langer model. At 3 years, the mean radiographic peri-implant bone loss was 0.69 ± 0.43 mm (platform switching) and 0.74 ± 0.57 mm (standard platform). The mean intraindividual difference was 0.05 ± 0.58 mm (95% confidence interval: –0.19, 0.29). Crestal bone-level alteration depended on time (p < .001) but not on platform type (p = .363). The present randomized clinical trial could not confirm the hypothesis of a reduced peri-implant crestal bone loss, when implants had been restored according to the concept of platform switching (ClinicalTrials.gov NCT01917305).

Randomized crossover study to examine the necessity of an injection-to-meal interval in patients with type 2 diabetes and human insulin.

OBJECTIVEPatients with diabetes and insulin therapy with human insulin were usually instructed to use an interval of 20–30 min between the injection and meal. We examined the necessity of the injection-to-meal interval (IMI) in patients with type 2 diabetes mellitus (T2DM) and flexible insulin therapy with human insulin.RESEARCH DESIGN AND METHODSIn this randomized, open crossover trial, 100 patients with T2DM (47% men, mean age = 66.7 years) were randomized to the IMI first group (phase 1, IMI 20 min; phase 2, no IMI) or IMI last group (phase 1, no IMI; phase 2, IMI 20 min). The main outcome measures were HbA1c, blood glucose profile, incidence of hypoglycemia, quality of life, treatment satisfaction, and patient preference.RESULTSForty-nine patients were randomized to the IMI first group and 51 patients to the IMI last group. Omitting the IMI only slightly increases HbA1c (average intraindividual difference = 0.08% [95% CI 0.01–0.15]). Since the difference is not clinically relevant, a therapy without IMI is noninferior to its application (P < 0.001). In the secondary outcomes, the incidence of mild hypoglycemia also did not differ between no IMI and IMI significantly (mean of differences = −0.10, P = 0.493). No difference in the blood glucose profile of both groups was found. Treatment satisfaction increased markedly, by 8.08, if IMI was omitted (P < 0.001). The total score of the quality of life measure did not show differences between applying an IMI or not. Insulin therapy without IMI was preferred by 86.5% of patients (P < 0.001).CONCLUSIONSAn IMI for patients with T2DM and preprandial insulin therapy is not necessary.

Intraocular Pressure During Acute Exposure to High Altitude

High altitude exposure is increasing owing to the constantly rising numbers of mountaineers and trekkers, and it is a clinically relevant cause of complex pathophysiological events leading to alterations in all parts of the body, including the visual system. Previous reports on intraocular pressure (IOP) changes during high altitude exposure have provided inconsistent and even conflicting results. The purpose of our study was to investigate the effect of acute high altitude exposure on IOP using state-of-the-art Goldmann applanation tonometry and to assess a correlation with AMS and vital parameters. Fourteen healthy lowlanders ascended from Tübingen, Germany (341 m), to the Capanna Margherita, Italy (4559 m), during the Tübingen High Altitude Ophthalmology research study within 24 hours, including 1 overnight stay at 3647 m. The IOP measurements using a Goldmann tonometer (Haag-Streit, Switzerland) and AMS scores (Lake Louise and AMS-c scores) were assessed twice daily; oxygen saturation (Spo2) and heart rate were monitored daily. Baseline recordings were taken before and at least 2 weeks after high altitude exposure at the University Eye Hospital in Tübingen. Intraindividual differences of IOP were calculated using multivariate analysis of variance and 95% CI. The IOP was decreased on day 2 by an average of −0.57 mm Hg (mean intraindividual difference; 95% CI: −1.71 to 0.56 mm Hg) and remained decreased during high altitude exposure; all values were statistically not significant compared with baseline. Incidence of AMS according to AMS scores was 50% on day 2. Subjects with AMS had lower Spo2 (71.70% ± 6.54%) and higher heart rate (85.70 ± 9.00 beats/min) compared with subjects not having AMS (74.30% ± 5.48% and 79.80 ± 9.9 beats/min, respectively), but no correlation with IOP was noted in regard to AMS. No significant change of IOP was noted during high altitude exposure over 4 days spent at high altitude compared with baseline. However, a tendency for a decreased IOP during high altitude exposure was noted. No correlation between IOP and AMS scores or clinical parameters was observed.

Estimulación audiovisual en niños con limitación grave de la motricidad: ¿mejora su calidad de vida?

Children with neurological diseases that impose severe limitations on their mobility have a deficient quality of life (QL). To study whether the QL of such patients improves with the application of a programme of audiovisual stimulation. A prospective study was conducted on nine children, six of whom were males (mean age: 42.6 ± 28.6 months), with severely limited mobility and who had been hospitalised for long periods. Two audiovisual stimulation programmes were produced and applied, together with videos, by means of a specially designed structure. The stimulus was applied twice a day for 10 minutes over 20 days. The first ten days the stimulus was carried out in a passive manner and the second block of ten days it was performed with the guidance of the observer. Biological, behavioural and cognitive variables were recorded and an adapted QL survey was applied. Three cases of spinal muscular atrophy, two of congenital muscular dystrophy, two of myopathy and two with other conditions were diagnosed. Eight patients completed the follow-up. From the baseline point of view, they presented a regular QL (7.2 ± 1.7 points; median: 7.0; range: 6-10), which improved to good on finishing the therapy (9.4 ± 1.2 points; median: 9.0; range: 8-11), with an intra-individual difference of 2.1 ± 1.6 (median: 2.5; range: -1 to 4; CI 95% = 0.83-3.42; p = 0.006). Improved cognition and a favourable perception in the caregivers were detected. No changes took place in the biological or behavioural variables. Audiovisual stimulation can be used to enhance the quality of life of children with severely limited mobility.

Reliability of V sit-and-reach test used for flexibility self-assessment in females

Background: The V sit-and-reach (VSR) test seems to be an appropriate instrument of self-assessment of hamstring and low-back flexibility for its ease of execution and the need for only a small amount of materials, space, and examination skill requirements. It is assumed that the specificity of self-assessment (in general) can be the cause of other sources of measurement error. Objective: This study aimed to analyze reliability of VSR when used as an instrument of self-assessment of flexibility in adolescent females. Methods: The sample comprised 43 students (female; age 21.2 ± 0.5 years) from Palacký University in Olomouc (Czech Republic). T-test (p < .05) and Pearson correlation coefficient was used to assess systematic bias and to determine intra-individual reliability of the flexibility test; the standard error of measurement (SEM) and Bland and Altman's 95% limits of agreement were used to assess absolute reliability of the flexibility test. Results: The average intra-individual difference of 1.14 cm (increasing test performance) was found to be statistical significant (t = -5,375; df = 42). It was observed that high intra-individual reliability (r = .98); the absolute reliability (SEM) is equal to 0.139 cm. Conclusions: This study provides evidence supporting the usage of VSR as a relevant instrument of self-assessment of hamstring and low-back flexibility in adolescent females.

Influence of tibial slope asymmetry on femoral rotation in patients with lateral patellar instability

PurposeThe geometry of the tibial plateau and its influence on the biomechanics of the tibiofemoral joint has gained increased significance. However, no quantitative data are available regarding the inclination of the medial and lateral tibial slope in patients with patellar instability. It was therefore the purpose of this study to evaluate tibial slope characteristics in patients with patellar dislocations and to assess the biomechanical effect of medial-to-lateral tibial slope asymmetry on lateral patellar instability.MethodsMedial and lateral tibial slope was measured on knee magnetic resonance images in 107 patients and in 83 controls. The medial-to-lateral tibial slope asymmetry was assessed as the intra-individual difference between the medial and lateral tibial plateau inclination considering severity of trochlear dysplasia. The effect of tibial slope asymmetry on femoral rotation was calculated by means of radian measure.ResultsSeverity of trochlear dysplasia was significantly associated with an asymmetric inclination of the tibial plateau. Whereas the medial tibial slope showed identical values between controls and study patients (n.s.), lateral tibial plateau inclination becomes flatter with increasing severity of trochlear dysplasia (p < 0.01). Consequently, the intra-individual tibial slope asymmetry increased steadily (p < 0.01) and increased internal femoral rotation in 20° and 90° of knee flexion angles in patients with severe trochlear dysplasia (p < 0.01). In addition, the extreme values of internal femoral rotation were more pronounced in patients with patellar instability, whereas the extreme values of external femoral rotation were more pronounced in control subjects (p = 0.024).ConclusionData of this study indicate an association between tibial plateau configuration and internal femoral rotation in patients with lateral patellar instability and underlying trochlear dysplasia. Thereby, medial-to-lateral tibial slope asymmetry increased internal femoral rotation during knee flexion and therefore might aggravate the effect of femoral antetorsion in patients with patellar instability.Level of evidenceIII.

‘Central sensitization’ in chronic neck/shoulder pain

Background and purpose‘Central sensitization’ (CS) may play a major role in maintaining several chronic pain conditions. CS has been proposed to play a significant role in a range of musculoskeletal pain conditions, such as trapezius myalgia, fibromyalgia, temporomandibular disorders, and low back pain. Whether CS varies over time within an individual is not known. This study evaluated (1) whether there is an intra-individual association between clinical pain and signs of CS, and (2) whether there is an inter-individual association between clinical pain and signs of CS. MethodsTwenty-seven sedentary workers (19 women, 8 men) with varying neck/shoulder pain participated in a pre-test and in two test sessions. On one of the test sessions the subjects had weak (or no) clinical pain (weak-pain day). On the other test session the subjects had stronger clinical pain (strong-pain day). As an indicator of ‘central sensitization’, we assessed the area of secondary pinprick hyperalgesia (tested by 84.4g/mm2 Von Frey hairs) in response to a first-degree burn to the volar forearm (contact heat, 46°C, 5min). While in the lab, the subjects’ current clinical pain intensity (0–10cm VAS) and distribution was assessed (PINTlab and PDISTlab). The subjects also rated their pain intensity and distribution retrospectively from the past 30days (PINT30d and PDIST30d). ResultsPINTlab was lower on the weak-pain day (1.7±1.5cm) than on the strong-pain day (4.3±1.6cm). This was also the case for the other clinical pain measures (PDISTlab, PINT30d and PDIST30d) and indicated that the participants were successfully recruited at days that differed in clinical pain severity. Despite a significant intra-individual difference in clinical pain between days, the area of secondary hyperalgesia did not differ between weak- and strong-pain days (50.3±13.5cm2 vs. 51.2±12.6cm2). Testing the inter-individual association between clinical pain and secondary hyperalgesia, we found a positive correlation between PINTlab and secondary hyperalgesia on the weak-pain day (rho=0.6), but not on the strong-pain day (rho=0.1). Given the stable secondary hyperalgesia across weak- and strong-pain days, this implies that subjects with a small secondary hyperalgesic area exhibited a relatively large variation in clinical pain between days, whereas subjects with a large secondary hyperalgesic area exhibited relatively small variation in clinical pain. ConclusionsWhen subjects are observed across days, ‘central sensitization’, measured as the area of secondary hyperalgesia after a first-degree burn, does not seem to be important for clinical pain intensity per se, but may be important for clinical pain variation. Subjects with indication of low ‘central sensitization’ seem to exhibit larger variation in pain between “good” and “bad” days than subjects with indication of high ‘central sensitization’. The study indicates that ‘central sensitization’ does not explain intra-individual variations in clinical pain. ImplicationsThis study raises the question of the role of ‘central sensitization’ in clinical musculoskeletal pain disorders. Furthermore, a precise definition of the ‘central sensitization’ concept is called for.

Transcorneal Electrical Stimulation Shows Neuroprotective Effects in Retinas of Light-Exposed Rats

To examine the effects of transcorneal electrical stimulation (TES) on retinal degeneration of light-exposed rats. Thirty-three Sprague Dawley albino rats were divided into three groups: STIM (n = 15) received 60 minutes of TES, whereas SHAM (n = 15) received identical sham stimulation 2 hours before exposure to bright light with 16,000 lux; healthy animals (n = 3) served as controls for histology. At baseline and weekly for 3 consecutive weeks, dark- and light-adapted electroretinography was used to assess retinal function. Analysis of the response versus luminance function retrieved the parameters Vmax (saturation amplitude) and k (luminance to reach ½Vmax). Retinal morphology was assessed by histology (hematoxylin-eosin [HE] staining; TUNEL assay) and immunohistochemistry (rhodopsin staining). Vmax was higher in the STIM group compared with SHAM 1 week after light damage (mean intra-individual difference between groups 116.06 μV; P = 0.046). The b-wave implicit time for the rod response (0.01 cd.s/m²) was lower in the STIM group compared with the SHAM group 2 weeks after light damage (mean intra-individual difference between groups 5.78 ms; P = 0.023); no other significant differences were found. Histological analyses showed photoreceptor cell death (TUNEL and HE) in SHAM, most pronounced in the superior hemiretina. STIM showed complete outer nuclear layer thickness preservation, reduced photoreceptor cell death, and preserved outer segment length compared with SHAM (HE and rhodopsin). This sham-controlled study shows that TES can protect retinal cells against mild light-induced degeneration in Sprague Dawley rats. These findings could help to establish TES as a treatment in human forms of retinal degenerative disease.