A direct neural measure of variable precision representations in visual working memory.

Visual working memory (VWM) is an active representation enabling the manipulation of item information even in the absence of visual input. A common way to investigate VWM is to analyze the performance at later recall. This approach, however, leaves uncertainties about whether the variation of recall performance is attributable to item encoding and maintenance or to the testing of memorized information. Here, we record the contralateral delay activity (CDA), an established electrophysiological measure of item storage and maintenance, in human subjects performing a delayed orientation precision estimation task. This allows us to link the fluctuation of recall precision directly to the process of item encoding and maintenance. We show that for two sequentially encoded orientation items, the CDA amplitude reflects the precision of orientation recall of both items, with higher precision being associated with a larger amplitude. Furthermore, we show that the CDA amplitudes for the items vary independently from each other, suggesting that the precision of memory representations fluctuates independently.NEW & NOTEWORTHY The present work demonstrates for the first time that the contralateral delay activity (CDA), an online electrophysiological measure of the number of representations maintained in memory, is also a reliable measure of the precision of memory representations. Furthermore, we show that the CDA fluctuates independently for individual items held in memory, thereby providing unambiguous direct neurophysiological support for independently fluctuating memory representations.

Social media and e-learning use among European exercise science students.

With the rise of digital technologies, electronic learning and communication tools are becoming a firm part of academia to promote knowledge of health sciences. This study sought to analyse the attitude of students regarding social media and digital learning for study purposes in sport and exercise science. A survey was carried out with a questionnaire (20 main items) in six sport science faculties, equally spread across Germany (G), Italy (I) and the United Kingdom (UK) between February and October 2017. The focus areas were students' usage of social media (Facebook, Google+, Instagram, LinkedIn, Skype, Twitter, WhatsApp, YouTube) for academic purposes and their use of e-learning. Data were analysed by quantitative and qualitative methods. 229 students participated in the study (G: 68, I: 121, UK: 40). While YouTube was mostly used for receiving knowledge, WhatsApp and Facebook showed additional preferences for peer contacts for learning purposes and knowledge discussions. Preferred online data sources were PubMed (77%), free access journals (67%), YouTube (66%) and Wikipedia (63%). Often used digital learning materials were own universities' PowerPoints (77%), scripts (59%) and scientific articles (53%). However, some preferences showed national differences. The evaluated participants showed an overall high use of social media and e-learning tools for their studies. Students would like more digital learning sources made available to them by their institutions. However, some differences in preferences of digital learning or communication tools may exist and this should be considered for international approaches to promote health knowledge among students.

Using the LHB score for assessment of LHB pathologies and LHB surgery: a prospective study.

INTRODUCTION: The long head of biceps tendon (LHB) score was designed to clinically assess LHB pathologies. Purpose of this study was to prospectively assess patients with LHB pathologies preoperatively and after LHB surgery using the LHB score. MATERIALS AND METHODS: Fifty-seven patients (29 f/28 m, Ø age 61.0 years), showing clinical signs of LHB pathologies, were prospectively included into this study. In 43 patients LHB pathologies could be confirmed intraoperatively. Among these, in 26 patients a biceps tenodesis (group I; 8 f/18 m, Ø age 61.2 years), and in 17 patients a biceps tenotomy was performed (group II; 12 f/5 m, Ø age 64.2 years). In 14 patients no intraoperative correlate concerning the biceps symptoms could be found (group III; 9 f/5m, Ø age 56.8 years). In these patients no further LHB treatment was carried out. The clinical evaluation contained the Constant score (CS) as well as the LHB score preoperatively and 2 years postoperatively. RESULTS: The CS improved significantly in all the three groups [group I: 41.7 (20-70) to 81.3 (62-100); group II: 42.2 (18-66) to 75.3 (41-84); group III: 45.7 (22-77) to 72.9 (48-85)] (p < 0.05). Also the LHB score increased significantly in all three groups [group I: 74.3 (41-97) to 94.2 (80-100); group II: 73.4 (57-97) to 84.2 (49-100); group III: 71.1 (58-80) to 90.8 (70-100)] (p < 0.05). Compared to group II, group I showed significant better results in the total LHB score and in the cosmetic result (p < 0.05). CONCLUSIONS: We recommend that patients with LHB pathologies are evaluated using the LHB score, since it provides LHB related information and is a proper tool to assess the clinical outcome after surgery. However, the score is not appropriate to detect LHB pathologies preoperatively. LEVEL OF EVIDENCE: II.

Form follows function: a computational simulation exercise on bone shape forming and conservation.

The present paper explores whether the shape of long bone shafts can be explained as a mere result of mechano-adapation. A computer simulation study was conducted in order to investigate adaptation processes of bone-like structures under load patterns comparable to those acting on the diaphysis of long bones. The aim of the study was to have a deeper look into the relationship between typical loading patterns and resulting bone shape and structure. The simulations are based on a mechanistic model approach for mechano-transduction and bone transformation. Results of the simulations are that axial torsion around the long axis is important for the evolvement and maintenance of tube-like structures. Of note such structures can form from a variety of starting geometries, provided that axial torsion is present. The selection of the set-point parameter for the regulation of load adapted bone transformation has an impact on the final structure as well. In conclusion, the present study confirms the mechanical environment's potential to generate shaft-like structures and demonstrates the respective boundary conditions.

Neonatal respiratory insufficiency caused by an (homozygous) ABCA3-stop mutation: a systematic evaluation of therapeutic options.

BACKGROUND: Autosomal recessive ABCA3 (ATP-binding cassette protein A3) gene mutations have been associated with neonatal respiratory distress and pediatric interstitial lung disease. The clinical course of the disease depends on the underlying mutations. Therefore, knowledge of course, symptoms and treatment of the disease is important. PATIENT AND METHODS: A term newborn suffered from progressive respiratory insufficiency, which led to death at the age of 4.8 months. The girl developed interstitial lung disease. Infections as well as structural and functional disorders of the lung were systematically excluded. A homozygous c.4681C > T (Arg 1561 Stop) mutation of the ABCA3 gene was identified. A literature review of the pathophysiology and treatment options of the disease was done. Therapeutic approaches with corticosteroids, macrolide, and hydroxychloroquine did not improve the clinical course. RESULTS: Therapeutic strategies for chronic interstitial lung disease have been used successfully in cases of a mild clinical course in juvenile patients with ABCA3 gene mutation. In our patient with homozygous ABCA3 gene mutation,they were not effective. Lung transplantation remains as a therapeutic option, but because of donor organ shortage and associated morbidity and mortality it is rarely feasible. CONCLUSION: More experience in the treatment of newborns with ABCA3 gene mutations is needed. Randomized, prospective evaluation of the different therapeutic approaches in a specific registry may improve prognosis and treatment of affected individuals.

Simvastatin modulates mouse embryonic stem cell-derived chondrogenesis in vitro.

It has been studied in detail that cellular differentiation during chondrogenesis can be recapitulated in vitro by differentiation of embryonic stem (ES) cells as embryoid bodies (EBs). We here used this model system of cartilage development to analyze the effect of simvastatin, a potentially embryotoxic substance. Statins are a group of drugs used to treat hypercholesterolaemia. We found that simvastatin activated cartilage nodule formation during EB differentiation. Extended application of simvastatin resulted in enhanced expression of cartilage marker molecules and prolonged persistence of cartilage nodules. Expression of collagen type II was upregulated during simvastatin-induced chondrogenic ES cell differentiation as demonstrated by quantitative real time PCR. However, immunostaining for cartilage marker molecules revealed that cartilage nodules within simvastatin-treated EBs were defective, bearing cavities of cell loss. Furthermore, caspase activity was reduced in comparison to untreated controls indicating reduced apoptosis. Taken together, we may speculate that simvastatin prolongs survival of chondrocytes and disrupts cellular integrity of cartilage nodules during EB development by affecting apoptotic mechanisms. The study underlines that ES cell-derived EBs are a useful in vitro model to screen substances for their embryotoxic and teratogenic potential.

Life-threatening bite injury of the lower lip after use of metamizole.

INTRODUCTION: Bite wounds of the oral mucosa heal after eliminating the causative irritant, but there are serious exceptions from the rule. We present the case of a 37-year-old woman with an ulcer of the mucosa of the lower lip, which had been present for 10 days, and leucopenia. DISCUSSION: Agranulocytosis after the use of metamizole is part from leukaemia and lues, a rare reason for non-healing ulcers of the mucosa of the oral cavity without fulminant signs for inflammation. CONCLUSION: As this is a life-threatening disease, medical therapy must begin immediately.

[Gaussian distribution of intelligence in VLBW preterm infants at age 5: very low correlation with very low birth weight]. / Normalverteilung der Intelligenz von VLBW-Frühgeborenen mit 5 Jahren: sehr geringe Korrelation mit sehr geringem Geburtsgewicht.

BACKGROUND: Preterm infants with very low birth weight < 1500 g (VLBW) have a higher risk of developmental disorders. In addition to the common estimation of the mean intelligence values, we studied the distribution of intelligence at preschool age in VLBW infants and the risk factors influencing this distribution. PATIENTS AND METHODS: A prospective cohort study of 277 VLBW infants < 32 weeks born in 1991-1995 and treated according to a standardized regimen in one Perinatal Center was carried out, including measurement of intelligence (Kaufman-Assessment Battery for Children) at age 5. Statistical methods employed were: explorative data analysis, correlation, chi (2)- and t-tests; the tested variables were: small for gestational age (< third percentile), perinatal acidemia (umbilical arterial pH < 7.10), perinatal hypoxia (BE < - 10), hypothermia (< 36 degrees C), hypoglycemia after the first day of life (< 30 mg / dL), bronchopulmonary dysplasia (FiO (2) > 0.21 > or = 36 weeks), intraventricular hemorrhage, ventricular dilation, periventricular leukomalacia, seizures, abnormal acoustic evoked potentials, and hyperexcitability at discharge. RESULTS: The distribution of intelligence in 137 VLBW infants < 32 weeks (60 % follow-up rate) was similar to a symmetrical Gaussian bell curve. The intelligence increased very slightly with birth weight (Pearson correlation: 0.172; p = 0.045) and was significantly lower in children with hypoglycemia after the first day of life (- 13.35; 95 % confidence interval: - 20.08 to - 6.63; p = 0.002), hyperexcitability at discharge (- 16.28; 95 % confidence interval: - 25.26 to - 7.31; p = 0.005), and bronchopulmonary dysplasia (- 7.00; 95 % confidence interval - 11.71 to - 2.29; p = 0.039). CONCLUSIONS: At preschool age, the intelligence of VLBW infants is normally distributed and correlates only slightly with the very low birth weight. Hypoglycemia after the first day of life and bronchopulmonary dysplasia are risk factors for lower intelligence. Hyperexcitability at discharge seemed to represent a promising prognostic factor for a later intelligence reduction.

A new method of monitoring osteomyelitis.

Chronic infections of bone such as osteomyelitis are frequent events, especially in immunocompromised or diabetic patients, and costly on a national level. Incorrect treatment or delayed diagnosis may lead to loss of the affected extremity or mandible. The aim of this study was to assess the possible value of urinary lysylpyridinoline (LP) and hydroxylysylpyridinoline (HP) concentrations in the monitoring of mandibular osteomyelitis. Patients were assigned to the following groups: group 1 (n=85), control; group 2a (n=38), patients with active disease; group 2b (n=25), patients of group 2a 6 months after successful treatment; group 2c (n=7), patients of group 2a with ongoing osteomyelitis 6 months after treatment. The range and upper limit of normal values (HP(max) and LP(max)) were determined in group 1. Levels of LP and HP were measured by high-performance liquid chromatography and fluorescence detection. There was a significant decrease (mean 45.43% for HP and 32.12% for LP) in samples of group 2b compared to 2a (P<0.001 for HP and LP). There was a significant increase in HP values in samples from group 2c compared to 2a (P=0.018). The urinary concentrations of HP and LP appear to act as a marker of disease activity, with a decrease reflecting treatment success and an increase or stable values indicating persistent disease. An inexpensive tool (US$5 per analysis) for the monitoring of osteomyelitis is described.

Learning by doing virtually.

Selective reduction of bone without collateral damage (nerves, teeth) is essential in apicectomy. To test whether skills acquired on a virtual apicectomy simulator (VOXEL-MAN system with integrated force-feedback) are transferable from virtual to physical reality, two groups of trainees were compared. Group 1 received computer-based virtual surgical training before performing an apicectomy in a pig cadaver model. The probability of preserving vital neighboring structures was improved significantly, i.e. six-fold, after virtual surgical training (P<0.001). The average volume of the bony defects created by the trainees of Group 2 (mean: 0.47 ml) was significantly (P<0.001) larger than by the trainees of Group 1 (mean: 0.25 ml). Most importantly, the ability to objectively self-assess performance was significantly improved after virtual training. Training with a virtual apicectomy simulator appears to be effective, and the skills acquired are transferable to physical reality.

Toxicity of synthetic musks to early life stages of the freshwater mussel Lampsilis cardium.

Polycyclic musk fragrances are common additives to many consumer products. As a result of their widespread use and slow degradation rates, they are widely found in aquatic environments. This study reports on the lethal and sublethal toxicity of the polycyclic musks AHTN (Tonalide) and HHCB (Galaxolide) to glochidial (larval) and juvenile life stages of the freshwater mussel Lampsilis cardium (Rafinesque, 1820). In glochidia, 24-h median lethal concentrations (LC50s) ranged from 454 to 850 microg AHTN/L and from 1000 to >1750 microg HHCB/L (water solubility). Results for 48-h tests were similar to the 24-h tests. In 96-h tests with juveniles, we did not observe a dose-response relation between mortality and either musk. However, the growth rate was reduced by musk exposure. The median effective concentrations (EC50s, based on growth) were highly variable and ranged from 108 to 1034 microg AHTN/L and 153 to 831 microg HHCB/L. While all adverse effects occurred at concentrations that are much greater than those reported in natural waters (low microg/L to ng/L), these results indicate the potential for adverse effects on these long-lived organisms from exposure to synthetic musk fragrances.

[Critical odontogenic infection involving the mediastinum. Case report]. / Kritische odontogene Infektion mit Mediastinalbeteiligung. Ein Fallbericht.

BACKGROUND: Occasionally, trivial odontogenic infections may develop into complex diseases. This may even result in an unrestrained phlegmonous spread causing life-threatening complications. These problems have decreased since the introduction of antibiotics and also due to improved oral hygiene and improved diagnostic measures resulting in optimized medical treatment. However, life-threatening forms are still seen, in particular if infections spread along the cervical fascial sheaths down towards to the mediastinum. Over the past decade the number of critical infections has increased in other medical specialties. This is usually explained by the development of multiresistant pathogens in the context of nosocomial infections. PATIENTS AND METHODS: We reviewed the patients' records of the past 15 years at the Department of Oral and Maxillofacial Surgery of the University Hospital Kiel to assess a possible increase of odontogenic infections with life-threatening complications. From 1990 to 2004, four patients with odontogenic infections exhibiting critical phlegmonous spread were treated in the intensive care unit. Two patients developed bacterial mediastinitis which could be controlled by intravenous antibiotics only. One patient progressed to general septic mediastinitis and eventually died of cardiorespiratory arrest. The last patient also had septic mediastinitis and developed right pleural empyema. Several operations were necessary before the disease could be controlled. This patient's case report is presented in detail. CONCLUSION: The prognosis of patients with mediastinitis crucially depends on (a) early diagnosis including computed tomography of the neck and thorax, (b) early radical surgical intervention, and (c) optimized pathogen-oriented antibiotic treatment.

Primary amides. A general nitrogen source for catalytic asymmetric aminohydroxylation of olefins.

N-Bromo,N-lithio salts of primary carboxamides have been shown to be efficient nitrogen sources for catalytic asymmetric aminohydroxylation of olefins, behaving much like the parent N-bromoacetamide in these reactions. alpha-Chloro-N-bromoacetamide is a particularly interesting nitrogen source, as it is functionalized for further reaction, including easy deprotection by treatment with thiourea.

Serum androgen levels in adolescents with type 1 diabetes: relationship to pubertal stage and metabolic control.

Delayed sexual maturation is still frequently seen in adolescents with type 1 diabetes. A close relationship between insulin and androgen metabolism has been found in a number of studies. Our study was designed to investigate whether or not abnormalities in androgen secretion could play a role in the onset of sexual maturation in adolescents with type 1 diabetes. We have asked whether or not there was a correlation between daily insulin dosage, duration of diabetes, metabolic control, age, pubertal stage, and body mass index (BMI) versus serum androgen concentrations. Basal total and free testosterone, dehydroepiandrosterone-sulfate (DHEA-S), dihydrotestosterone (DHT), sex hormone binding globulin (SHBG) and 3alpha-androstanediol glucuronide (3alpha diol-G) plasma concentrations were measured in 36 pubertal boys and 31 pubertal girls with type 1 diabetes and in 59 sex- and pubertal stage-matched control subjects without diabetes. Significantly higher serum total testosterone (p<0.01) and free testosterone (p<0.05) levels were found in females and males with type 1 diabetes than in controls at pubertal stage 5. DHEA-S, SHBG, DHT and 3alpha diol G concentrations in patients with diabetes were not significantly different from those in controls. There was no correlation between daily insulin requirements and serum androgen levels. These data suggest that adolescents with diabetes have similar serum levels of DHEA-S, SHBG, DHT and 3alpha diol G as healthy subjects at all stages of puberty. However, there are significant differences in serum testosterone and free testosterone levels in adolescents with diabetes when compared to healthy, sex- and pubertal stage-matched controls in late puberty. We hypothesize that the increased testosterone levels in patients with diabetes could relate to reduced fertility in females, disorders of sexual maturation and an increased risk for cardiovascular complications later in life.

[Hearing screening of high risk newborn infants]. / Hörscreening von Neugeborenen mit Risikofaktoren.

OBJECTIVE: This prospective study reports on the prevalence of hearing impairment in an at-risk neonatal intensive care unit (NICU) population. DESIGN: From 1990 to 1998, 1062 neonates were screened with the use of transitory evoked otoacoustic emissions (TEOAE) and brainstem evoked response audiometry (BERA). RESULTS: 934 infants passed the primary screen for both ears, 75 for one ear, adding up to 95%. 17 infants (1.6%) were lost to follow-up. In fourteen infants (1.3%), bilateral hearing impairment above 30 dB was confirmed. While all children with hearing impairment belonged to the group of 862 children receiving aminoglycosides, only one of them presented no other risk factors. In twelve of the hearing impaired children other anamnestic factors, i.e. dysmorphism, prenatal rubella or cytomegaly, family history of hearing loss or severe peri- and postnatal complications seem to be more probable causes of the identified hearing loss. In one of these children, delayed onset or progression of hearing loss is suspected. CONCLUSIONS: From our data, aminoglycosides are not an important risk factor for hearing impairment, when serum levels are continuously monitored, as in our cohort. After adjustment for other risk factors, birth weight between 1000 gr and 1500 gr and a gestational age between 29 and 31 weeks were no predictive markers for hearing impairment. It might be speculated that the improved medical treatment in a NICU reduces the probability of hearing impairment for those two groups. Conductive hearing loss as a possible additional cause for hearing impairment was not studied in detail, but the high percentage of malformations detected (four out of fourteen hearing impaired infants) demands further monitoring, close follow-up, adequate treatment and counselling.

Expression of apoptosis and cell cycle related genes in proliferating and colcemid arrested cells of divergent lineage.

Progression through the cell cycle and redirection of cells towards programmed cell death (apoptosis) are tightly inter-related processes. However the requirement for tissue and cell type specificity suggests that a wide variety of mechanisms are used to achieve the same purpose. To examine this issue, we investigated cell cycle (c-myc, p53, p21/WAF) and apoptosis related (bcl-2, bcl-X(L), bax-alpha) gene expression in two cell lines of very different origin under proliferating and apoptosis-inducing conditions. Transformed human osteosarcoma cells (MG63) and non-transformed human kidney embryonal fibroblasts (293-0) were kept in culture in medium containing 10% FCS and growth arrest was induced by the addition of 50 ng/ml colcemid. Colcemid treatment caused growth arrest and elevated expression of cyclin B1 protein in both cell lines. Apoptosis was significantly elevated in both cell lines after colcemid exposure for at least one cell cycle. However the pattern of expression of cell cycle and apoptosis related genes, determined by RT-PCR, was quite different between the two cell lines during exponential growth and cell cycle arrest. Colcemid treatment did not markedly influence c-myc, p53 and p21/WAF expression in MG63 cells but did suppress c-myc and increase p21/WAF in 293-0 cells. Furthermore colcemid treated MG63 cells exhibited elevated bcl-2 and bax-alpha expression while similar treatment of 293-0 cells resulted in decreased bcl-X(L) and slightly increased bax-alpha expression. While growth arrest and apoptosis were induced in both MG63 and 293 cells following colcemid treatment, the differences in gene expression suggest that the mechanism by which these cells determine cell fate is quite different and may determine the sensitivity of different cell populations to anti-neoplastic drug therapy. The distinct patterns of gene expression should be carefully defined before mechanisms of apoptotic cell death are studied.

High-Temperature In Situ Straining Experiments in the High-Voltage Electron Microscope.

: Design rules are described here for high-temperature straining stages for transmission electron microscopy. Temperatures above 1000 degreesC can be attained by electron bombardment of the specimen grips. Thermal equilibrium can be reached in a short time by carrying off the heat by water cooling. Some applications of this stage are described. Ferroelastic deformation was observed at 1150 degreesC in t' and partially stabilized zirconia, which changes the microstructure for successive dislocation plasticity. In the oxide-dispersion-strengthened alloy INCOLOY MA 956, dislocations are impeded by oxide particles and move smoothly between the particles. At high temperatures, both the resting and traveling times control the average dislocation velocity. In MoSi2 single crystals of a soft orientation, dislocations with 1/2<111> Burgers vectors are created in localized sources and move on {110} planes in a viscous manner. The dislocations in Al-Pd-Mn single quasicrystals are oriented in preferred crystallographic directions and move in a viscous way as well. On the basis of in situ observations, conclusions are drawn for interpreting macroscopic deformation behavior at high temperatures.

Hearing screening in at-risk neonate cohort.

OBJECTIVE: This prospective study reports on the prevalence of hearing impairment in an at-risk neonatal intensive care unit (NICU) population. DESIGN: From 1990 to 1997, 942 neonates were screened with transient evoked otoacoustic emissions (TEOAE) and brainstem evoked response audiometry (BERA). RESULTS: 835 Infants passed the primary screen for both ears, 57 for one ear, adding up to 94.7%. Seventeen infants (1.9%) were lost to follow-up. In thirteen infants (1.4%), bilateral hearing impairment above 30 dB was confirmed. While all children with hearing impairment belonged to the group of 820 children receiving aminoglycosides, only one presented no other risk factors. In 11 of the hearing impaired children other anamnestic factors, i.e. dysmorphism, prenatal rubella or cytomegaly, family history of hearing loss or severe peri- and postnatal complications seem to be more probable causes of the identified hearing loss. CONCLUSIONS: From our data, aminoglycosides seem not to be an important risk factor for communication related hearing impairment, when serum levels are continuously monitored, as occurred in our cohort. After adjustment for other risk factors, birth weight between 1000 and 1500 g and a gestational age between 29 and 31 weeks were no predictive markers for hearing impairment. It might be speculated that the improved medical treatment in a Neonatal Intensive Care Unit (NICU) reduces the probability of hearing impairment for those two groups. Conductive hearing loss as a possible additional cause for hearing impairment was not studied in detail, but the high percentage of malformations detected (four out of 13 hearing impaired infants) demands further monitoring, close follow-up, counselling and adequate treatment.