Asteroseismology. Echography of young stars reveals their evolution

We demonstrate that a seismic analysis of stars in their earliest evolutionary phases is a powerful method with which to identify young stars and distinguish their evolutionary states. The early star that is born from the gravitational collapse of a molecular cloud reaches at some point sufficient temperature, mass, and luminosity to be detected. Accretion stops, and the pre-main sequence star that emerges is nearly fully convective and chemically homogeneous. It will continue to contract gravitationally until the density and temperature in the core are high enough to start nuclear burning of hydrogen. We show that there is a relationship for a sample of young stars between detected pulsation properties and their evolutionary status, illustrating the potential of asteroseismology for the early evolutionary phases.

The Val158Met COMT polymorphism is a modifier of the age at onset in Parkinson's disease with a sexual dimorphism

The catechol-O-methyltranferase (COMT) is one of the main enzymes that metabolise dopamine in the brain. The Val158Met polymorphism in the COMT gene (rs4680) causes a trimodal distribution of high (Val/Val), intermediate (Val/Met) and low (Met/Met) enzyme activity. We tested whether the Val158Met polymorphism is a modifier of the age at onset (AAO) in Parkinson's disease (PD). The rs4680 was genotyped in a total of 16 609 subjects from five independent cohorts of European and North American origin (5886 patients with PD and 10 723 healthy controls). The multivariate analysis for comparing PD and control groups was based on a stepwise logistic regression, with gender, age and cohort origin included in the initial model. The multivariate analysis of the AAO was a mixed linear model, with COMT genotype and gender considered as fixed effects and cohort and cohort-gender interaction as random effects. COMT genotype was coded as a quantitative variable, assuming a codominant genetic effect. The distribution of the COMT polymorphism was not significantly different in patients and controls (p=0.22). The Val allele had a significant effect on the AAO with a younger AAO in patients with the Val/Val (57.1±13.9, p=0.03) than the Val/Met (57.4±13.9) and the Met/Met genotypes (58.3±13.5). The difference was greater in men (1.9 years between Val/Val and Met/Met, p=0.007) than in women (0.2 years, p=0.81). Thus, the Val158Met COMT polymorphism is not associated with PD in the Caucasian population but acts as a modifier of the AAO in PD with a sexual dimorphism: the Val allele is associated with a younger AAO in men with idiopathic PD.

Corticomuscular coherence in asymptomatic first-degree relatives of patients with essential tremor

BACKGROUND

Essential tremor (ET) follows an autosomal dominant type of inheritance in the majority of patients, yet its genetic basis has not been identified. Its exact origin is still elusive, but coherence measurements between electromyography tremor bursts and electroencephalography unequivocally demonstrate a correlation.

METHODS

We tested these measurements in 37 healthy first-degree relatives (children) of patients with essential tremor (ET) and a group of 37 age-matched and sex-matched controls. Pooled coherence spectra of the maximally coherent electroencephalogram electrodes were computed for ET relatives and controls.

RESULTS

The maximal coherence and its frequency were significantly higher in ET relatives than in controls during the pinch grip task and during slow hand movements. Electromyography amplitude (root-mean-square) was slightly but significantly greater in ET relatives, whereas 2-Hz to 40-Hz power and spectral peak frequency were not different.

CONCLUSIONS

The presymptomatic alteration in corticomuscular interaction may reflect a role of genetic factors.

Visualization of Astronomical Nebulae via Distributed Multi-GPU Compressed Sensing Tomography

The 3D visualization of astronomical nebulae is a challenging problem since only a single 2D projection is observable from our fixed vantage point on Earth. We attempt to generate plausible and realistic looking volumetric visualizations via a tomographic approach that exploits the spherical or axial symmetry prevalent in some relevant types of nebulae. Different types of symmetry can be implemented by using different randomized distributions of virtual cameras. Our approach is based on an iterative compressed sensing reconstruction algorithm that we extend with support for position-dependent volumetric regularization and linear equality constraints. We present a distributed multi-GPU implementation that is capable of reconstructing high-resolution datasets from arbitrary projections. Its robustness and scalability are demonstrated for astronomical imagery from the Hubble Space Telescope. The resulting volumetric data is visualized using direct volume rendering. Compared to previous approaches, our method preserves a much higher amount of detail and visual variety in the 3D visualization, especially for objects with only approximate symmetry.

Polymorphisms in the glial glutamate transporter SLC1A2 are associated with essential tremor

OBJECTIVE

Sporadic, genetically complex essential tremor (ET) is one of the most common movement disorders and may lead to severe impairment of the quality of life. Despite high heritability, the genetic determinants of ET are largely unknown. We performed the second genome-wide association study (GWAS) for ET to elucidate genetic risk factors of ET.

METHODS

Using the Affymetrix Genome-Wide SNP Array 6.0 (1000K) we conducted a two-stage GWAS in a total of 990 subjects and 1,537 control subjects from Europe to identify genetic variants associated with ET.

RESULTS

We discovered association of an intronic variant of the main glial glutamate transporter (SLC1A2) gene with ET in the first-stage sample (rs3794087, p = 6.95 × 10(-5), odds ratio [OR] = 1.46). We verified the association of rs3794087 with ET in a second-stage sample (p = 1.25 × 10(-3), OR = 1.38). In the subgroup analysis of patients classified as definite ET, rs3794087 obtained genome-wide significance (p = 3.44 × 10(-10), OR = 1.59) in the combined first- and second-stage sample. Genetic fine mapping using nonsynonymous single nucleotide polymorphisms (SNPs) and SNPs in high linkage disequilibrium with rs3794087 did not reveal any SNP with a stronger association with ET than rs3794087.

CONCLUSIONS

We identified SLC1A2 encoding the major glial high-affinity glutamate reuptake transporter in the brain as a potential ET susceptibility gene. Acute and chronic glutamatergic overexcitation is implied in the pathogenesis of ET. SLC1A2 is therefore a good functional candidate gene for ET.

[A rare cause of recurrent small bowel intussusception. Case report and review of the literature]

Small bowel intussusception is a rare cause of abdominal pain in adult patients. Due to varying symptoms and different underlying causes its diagnosis and treatment is challenging for physicians. This case report describes recurrent intussusception in an adult female patient and celiac disease could only be diagnosed as the cause of these symptoms after surgery. In addition a review of the literature regarding adult intussusception is presented.

A combination of galantamine and memantine modifies cognitive function in subjects with amnestic MCI

OBJECTIVES

Mild cognitive impairment (MCI) is etiologically heterogeneous, and a substantial proportion of MCI subjects will develop different dementia disorders. One subtype of this syndrome, amnestic MCI, occurs preferentially but not exclusively in prodromal AD and is characterized by defined deficits of episodic memory.

DESIGN, SETTING AND PARTICIPANTS

For a 2-year, double-blinded, placebo-controlled study MCI patients, presenting with an amnestic syndrome but not necessarily based on presumed prodromal AD were randomized.

INTERVENTION

Patients received (a) a combination of 16 mg galantamine plus 20 mg memantine, or (b) 16 mg galantamine alone or (c) placebo.

MEASUREMENTS

The primary objective was to explore the differential impact of these interventions on the progression to dementia and on cognitive changes as measured by the ADAScog.

RESULTS

After recruitment of 232 subjects, the trial was halted before reaching the planned sample size, because safety concerns arose in other studies with galantamine in MCI. This resulted in a variable treatment duration of 2-52 weeks. The statistical analysis plan was amended for studying cognitive effects of discontinuing the study medication, which was done separately for galantamine and memantine, and under double-blind conditions. There was one death, no unexpected severe adverse events, and no differences of severe adverse events between the treatment arms. The cognitive changes on the ADAScog were not different among the groups. Only for the subgroup of amnestic MCI with presumed AD etiology, a significant improvement of ADAScog score over placebo before the discontinuation of medication was observed, while amnestic MCI presumably due to other etiologies showed no cognitive changes with broad variation. Cognitive improvement was numerically larger in the combination treatment group than under galantamine alone. Patients who received placebo declined as expected. Discontinuation of galantamine, either as part of the combination regimen or as mono treatment, resulted in a transient decline of the ADAScog score in amnestic MCI of presumed AD etiology, while discontinuation of Memantine did not change the cognitive status.

CONCLUSION

In an interrupted trial with amnestic MCI subjects the combination of galantamine plus memantine were generally well tolerated. In the subgroup of MCI subjects with presumed AD etiology, a cognitive benefit of a short-term combination treatment of galantamine plus memantine was observed, and cognitive decline occurred after discontinuation of galantamine.

A clinical test for the alcohol sensitivity of essential tremor

BACKGROUND

The objective of the study was to develop a simple diagnostic test for alcohol sensitivity of essential tremor patients. Here we describe the controlled measurements of tremor severity after alcohol ingestion and the practicability of using it as a home test.

METHODS

Ten patients were tested for alcohol sensitivity under controlled conditions in the laboratory (blood alcohol, quantitative tremor recordings, modified Fahn scale, visual analog scale, Archimedes spirals), and 15 patients were instructed to perform an alcohol test at home (visual analog scale, Archimedes spirals) following an adapted dosage of alcohol.

RESULTS

The time course of the antitremor effect showed significant improvement of up to 50% in both groups for all the outcome parameters. Tremor deteriorated after 3 hours. A quarter of the patients noticed the alcohol effect for the first time during the test.

CONCLUSIONS

Alcohol is an effective drug for essential tremor. Its effect is only short-lived and exhibits a rebound after > 3 hours and the next morning. We propose this essential tremor home test as a diagnostic tool to confirm the alcohol sensitivity of essential tremor.

The psychosocial burden of essential tremor in an outpatient- and a community-based cohort

BACKGROUND AND PURPOSE

To compare psychosocial burden in patients with essential tremor (ET) in an outpatient (OPC)- and a community-based cohort (CBC).

METHODS

A sample of outpatients of a tertiary referral center (n = 180) and a community-based sample (n = 100) with ET were asked for study participation. Psychosocial aspects were assessed by a questionnaire on psychosocial aspects of ET, neuropsychological scales, quality of life, personality traits, and coping strategies.

RESULTS

One hundred and seven patients of the OPC and 90 individuals of the CBC participated and their results are descriptively presented. Statistical analysis was restricted to 38 pairs of OPC and CBC individuals matched for age, sex, and tremor severity. One-third of these individuals reported a profound impairment in everyday or professional life. Neuropsychological scales showed a severe depression in 8% of the individuals and pathologic values for the general level of psychiatric symptoms in 26%. The main coping strategy was 'active problem-orientated coping'. Patients of the OPC perceived a more severe impact of ET on their life. Multivariate analysis revealed the Beck Depression Inventory score as the only predictive factor for the outcome variables, physical and mental component scores, of the SF-12 health survey.

CONCLUSIONS

ET causes a significant psychosocial impairment, which does depend on symptom severity but also on mood with depression as the main driving factor and other so far undetermined factors.

GABA(A) receptor- and GABA transporter polymorphisms and risk for essential tremor

BACKGROUND

Clinical features and animal models of essential tremor (ET) suggest gamma-aminobutyric acid A receptor (GABA(A) R) subunits and GABA transporters as putative candidate genes.

METHODS

A total of 503 ET cases and 818 controls were investigated for an association between polymorphisms in 15 GABA(A) R and four GABA transporter genes and ET.

RESULTS

Nine nominally significant tagging SNPs (P values from 4.9×10(-2) to 5.2×10(-4) ) were found in the hypothesis generation stage. Five SNPs were followed up in a second verification stage but failed to reach significance. (P values from 0.30 to 0.77).

DISCUSSION

In our samples, no evidence of association between GABA(A) R and GABA transporter genes with ET was detected. Further studies are necessary to clarify the role of these genes in ET.

Endoscopic closure of postoperative esophageal leaks with a novel over-the-scope clip system

Management of esophageal anastomotic leaks is associated with high morbidity and mortality and remains an interdisciplinary challenge. We describe the first two cases of endoscopic closure of postoperative leaks following gastrectomy and primary repair after spontaneous acute esophageal perforation, using the over-the-scope clip (OTSC) system (Ovesco Endoscopy GmbH, Tübingen, Germany). Both leaks were successfully sealed with one clip. While one patient recovered without reintervention, in the other patient the postoperative leak reappeared following clip displacement 13 days later.

LINGO1 is not associated with Parkinson's disease in German patients

Essential tremor (ET) and Parkinson's disease (PD) are the most common movement disorders and show clinical, genetic, and pathophysiological overlap. Single-nucleotide polymorphisms (SNPs) in the leucine-rich repeat (LRR) and immunoglobulin (Ig) domain-containing, Nogo receptor-interacting protein gene (LINGO1) are associated with ET. LINGO1 is overexpressed in the substantia nigra (SN) of PD patients and inhibition of LINGO1 confers neuroprotection in a rodent model of PD. In this study we test the hypothesis whether SNPs in the LINGO1 gene that are associated with ET are also associated with PD. Three large German case-control samples from Kiel, Lübeck, and Tübingen (total: 1,798 cases and 1,482 controls) were genotyped for the three LINGO1 SNPs associated with ET. Association was assessed using allele- and genotype-based tests in each of the three samples separately, in the combined sample, and in subsets of patients with early-onset PD (<50 years) and of patients with a positive family history of PD. Neither of the three samples alone nor the combined sample showed evidence for association between LINGO1 SNPs and PD. The allele-based test showed a trend toward nominal association for all three SNPs in the Kiel sample. The subsets with early-onset PD or a positive family history did also not reveal evidence for association. SNPs in the LINGO1 gene associated with ET could not be shown to be associated with PD in our study population, despite a postulated overlap between both diseases.

Endoscopic closure of postoperative esophageal leaks with a novel over-the-scope clip system

Management of esophageal anastomotic leaks is associated with high morbidity and mortality and remains an interdisciplinary challenge. We describe the first two cases of endoscopic closure of postoperative leaks following gastrectomy and primary repair after spontaneous acute esophageal perforation, using the over-the-scope clip (OTSC) system (Ovesco Endoscopy GmbH, Tübingen, Germany). Both leaks were successfully sealed with one clip. While one patient recovered without reintervention, in the other patient the postoperative leak reappeared following clip displacement 13 days later.

Accuracy of endoscopic ultrasound in preoperative staging of esophageal cancer: results from a referral center for early esophageal cancer

BACKGROUND AND STUDY AIM

Endoscopic ultrasound (EUS) has been regarded as the most accurate staging tool in esophageal cancer. Staging results have a strong impact on the decision as to whether a patient should undergo endoscopic treatment, surgery alone, or neoadjuvant therapy. This retrospective study was conducted to analyze the accuracy of esophageal cancer staging using EUS.

METHODS

All patients who received EUS for staging of esophageal cancer before esophagectomy from February 2003 to December 2007 at a high volume academic tertiary care center were included.

RESULTS

179 consecutive patients (mean age 64.4 +/- 9.5 years; 142 men) underwent esophageal resection for Barrett's adenocarcinoma (n = 134) and squamous cell cancer (n = 45). Postoperatively, 99 patients were staged as having T1 cancers (55 %), 30 patients T2 (17%), 46 patients T3 (26%), and four patients T4 (2%). The sensitivity and specificity of EUS relative to the T stage were 82% and 91%, respectively, for T1; 43% and 85% for T2; and 83% and 86% for T3. The overall accuracy for EUS in identifying the correct T stage was 74% (95%CI 66-80). Positive lymph nodes were diagnosed histologically in 68 patients (38%). The sensitivity, specificity and accuracy of EUS for the diagnosis of N1 were 71%, 74% and 73% (95%CI 65-79), respectively.

CONCLUSIONS

The diagnostic accuracy of EUS in patients with esophageal cancer is still unsatisfactory. T2 cancers in particular are frequently overstaged, with a significant effect on the subsequent treatment strategy.