A Tandetron™ as proton injector for the eye tumor therapy in Berlin

The therapy of eye tumors with fast protons is an excellent tool giving very high local control rates. At the Helmholtz-Zentrum Berlin (HZB) almost 1800 patients were treated since 1998. A 2 MV Tandetron™ was installed as injector for the k = 132 HZB cyclotron. Using the standard 358 duoplasmatron ion source with direct extraction of negative hydrogen ions an extremely stable proton beam can be delivered, both on the short-term and the long-term scale. The hair-needle filaments made from thoriated tungsten wires have safe operation times of more than 1000 h.

Removal of bacteriophages with different surface charges by diverse ceramic membrane materials in pilot spiking tests

This study examines mechanisms for removal of bacteriophages (MS2 and phiX174) by ceramic membranes without application of flocculants. The ceramic membranes considered included ultra- and microfiltration membranes of different materials. Phages were spiked into the feed water in pilot scale tests in a waterworks. The membranes with pore sizes of 10 nm provided a 2.5-4.0 log removal of the phages. For pore sizes of 50 nm, the log removal dropped to 0.96-1.8. The membrane with a pore size of 200 nm did not remove phages. So, the removal of both MS2- and phiX174-phages depended on the pore size of the membranes. But apart from pore size also other factors influence the removal of phages. Removal was 0.5-0.9 log higher for MS2-phages compared with phiX174-phages. Size exclusion seems to be the major but not the only mechanism which influences the efficiency of phage removal by ceramic membranes.

Low copy number DNA profiling from isolated sperm using the aureka®-micromanipulation system

A new cell isolation technique linked to the aureka® micromanipulation system (aureka®) was used to pick sperm from mixed samples containing sperm and epithelial cells. Both cell types were stained using the HY-LITER™ high-resolution, fluorescent staining kit. To isolate a single sperm of interest under a fluorescent microscope, a specific microsphere picking technique was used. This sensitive and reliable cell identification and isolation technique enables low-copy-number (LCN) DNA profiling, as few as 20 sperm are sufficient for obtaining a full short tandem repeat (STR) profile without any allelic drop out. The presented protocol covers the whole workflow, from sample staining and cell pick up to STR analysis.

[Effects of daily physical exercise at school on cardiovascular risk--results of a 2-year cluster-randomized study]

BACKGROUND AND OBJECTIVE

It was the aim of this study to measure the effects over two years of daily sport activity during the school-day on their physical fitness (primary endpoint), motor coordination and blood pressure (secondary endpoints).

METHODS

A total of 232 children from eleven different 6 (th) grade classes were enrolled after informed parental consent. Their mean age was 11.1  ±  0.6 years. Six classes were randomly assigned for intervention (n=141), five as control (n=91). Those of the intervention cohort undertook, for five days weekly during the school year one hour of regulated sport exercise, including 15 min of endurance training. The pupils of the control group undertook customary sport activity (two hours a week). Anthropometric data were recorded and maximal oxygen uptake measured in each pupil, as well as blood pressure and motor coordination at the beginning and at the end of each of the two years of the study. The data were analyzed using the cluster randomization method.

RESULTS

Maximal oxygen uptake (VO (2)max) had improved among the intervention group after two years, compared with the controls (3.12 m/kg/min, 95% confindence interval [CI] 0.06-6.19), while improvement in motor coordination just failed to reach statistical significance (3.06, 95% CI -0.17-6.29). There was no significant difference in systolic and diastolic blood pressure, but a downward trend in the prevalence of overweight and obesity from 12.1% to 7.8% in the intervention group.

CONCLUSION

The results indicate that daily physical exercise during school hours should be given greater importance. But it will require a long-term trial to determine whether promotion of increased physical activity at school influences the prevalence of cardiovascular risk factors when the pupils reach adulthood.

Physiological and conjugated linoleic acid-induced changes of adipocyte size in different fat depots of dairy cows during early lactation

The aim of this study was to investigate the effects of lactation and conjugated linoleic acid (CLA) supplementation on adipocyte sizes of subcutaneous (s.c.) and visceral (VC) fat depots in primiparous dairy cows during the first 105 d in milk (DIM). German Holstein heifers (n=25) were divided into a control (CON) and a CLA group. From 1 DIM until sample collection, CLA cows were fed 100g of CLA supplement/d (about 6% of c9,t11 and t10,c12 isomers each), whereas the CON cows received 100g of fatty acid mixture/d instead of CLA. The CON cows (n=5 each) were slaughtered at 1, 42, and 105 DIM, and the CLA cows (n=5 each) were slaughtered at 42 and 105 DIM. Adipose tissues from 3s.c. depots (tailhead, withers, and sternum) and from 3 VC depots (omental, mesenteric, and retroperitoneal) were sampled. Hematoxylin-eosin staining was done to measure adipocyte area (μm(2)). Retroperitoneal adipocyte sizes were mostly larger than adipocytes from the other sites, independent of lactation time and treatment. Significant changes related to duration of lactation were limited to retroperitoneal fat: adipocyte sizes were significantly smaller at 105 DIM than at 1 DIM in CON cows. Adipocyte sizes were decreased in s.c. depots from the tailhead at 105 DIM and from the sternum at 42 DIM in CLA versus CON cows, whereas for VC depots, adipocyte sizes were decreased in mesenteric fat at 42 and 105 DIM, and in omental and retroperitoneal fat, at 105 DIM in CLA versus CON cows. Within the CLA group, adipocyte sizes were smaller in the s.c. depot from the tailhead at 105 DIM than at 42 DIM. Adipocyte sizes and depot weights were significantly correlated in s.c. depots (r=0.795) in the CLA group and in retroperitoneal fat both in the CON (r=0.698) and the CLA (r=0.723) group. In conclusion, CLA-induced decreases in adipocyte size indicate lipolytic or antilipogenic effects of CLA, or both effects, on adipose tissue in primiparous dairy cows.

An increase in serum tryptase even below 11.4 ng/mL may indicate a mast cell-mediated hypersensitivity reaction: a prospective study in Hymenoptera venom allergic patients

BACKGROUND

During a systemic hypersensitivity reaction (SR), an increase in serum tryptase compared to the baseline value is an indicator of mast cell activation, most often due to an IgE-mediated mechanism.

OBJECTIVE

To study the relevance of an increase in serum tryptase below the upper normal value of 11.4 ng/mL.

METHODS

Serum tryptase levels were measured in 35 patients with Hymenoptera venom hypersensitivity before and during venom exposure. Of these, 20 developed SR to stings or following venom injections during immunotherapy (reactors), while 15 tolerated reexposure to stings or venom injections during immunotherapy without SR (non-reactors). Serum tryptase was estimated at 2, 5 and 24 h after exposure and was compared to a baseline value obtained before or at least 72 h after exposure.

RESULTS

Considering circadian variation of serum tryptase, a relative increase to ≥135% of the baseline value (relative delta bound) was defined to indicate mast cell activation. Such an increase was observed in 17 of 20 reactors (85%), but none of 15 non-reactors. A serum tryptase of ≥11.4 ng/mL following venom exposure was observed in eight of the 20 reactors (40%) and 2 (13.3%) of the 15 non-reactors. Both these non-reactors also had an elevated baseline serum tryptase.

CONCLUSIONS AND CLINICAL RELEVANCE

Serum tryptase values obtained during a suspected hypersensitivity reaction must always be compared to a baseline value. A relative tryptase increase to ≥135% of the baseline value during a suspected hypersensitivity reaction indicates mast cell activation even below 11.4 ng/mL.

TRACP 5b and CTX as osteological markers of delayed fracture healing

Radiological studies are the standard method to monitor fracture healing but they do not allow a timely assessment of bone healing. Biochemical markers react rapidly to changes in bone metabolism during fracture healing and could be an additional tool to monitor this process. The goal of this study was to observe changes in serum biomarkers and evaluate the possible differences in the serum levels of tartrate-resistant acid phosphatase 5b (TRACP 5b), total N-terminal propeptide of type I collagen (PINP), bone-specific alkaline phosphatase (BAP), and C-terminal cross-linking telopeptide of type I collagen (CTX) in patients with normal and delayed fracture healing. Several serum samples were collected for one year after the surgical treatment of long bone fractures in 248 patients. From this large pool, 15 patients with atrophic nonunion were matched to 15 patients with normal bone healing. Post-operative changes in osteological markers were monitored during the 1st, 2nd, 4th, 8th, 12th and 52nd weeks. The patients were followed both clinically and radiologically for the entire one-year duration of the study. In the first week, the absolute values of CTX decreased significantly (p=0.0164) in cases of delayed fracture healing. The relative values of TRACP 5b were significantly decreased at weeks 4 (p=0.0066) and 8 (p=0.0043). BAP and PINP levels decreased in the first week followed by an increase, but there were no significant differences in the absolute or relative values during the healing process in both patient groups. For the first time, we have demonstrated changes in serum concentrations of TRACP 5b, PINP, BAP, and CTX during normal and delayed fracture healing. Characteristic changes in systemic TRACP 5b and CTX levels could reflect the initial process of successful fracture healing and may be used in clinical practice to monitor the healing process. Furthermore, it could be very important for determining the beneficial effects of additional treatments such as ultrasound or BMPs in clinical trials.

Search for light gauge bosons of the dark sector at the Mainz Microtron

A new exclusion limit for the electromagnetic production of a light U(1) gauge boson γ' decaying to e + e- was determined by the A1 Collaboration at the Mainz Microtron. Such light gauge bosons appear in several extensions of the standard model and are also discussed as candidates for the interaction of dark matter with standard model matter. In electron scattering from a heavy nucleus, the existing limits for a narrow state coupling to e + e- were reduced by nearly an order of magnitude in the range of the lepton pair mass of 210 MeV/c2}<me +}e-<300 MeV/c2. This experiment demonstrates the potential of high current and high resolution fixed target experiments for the search for physics beyond the standard model.

Effects of two dopamine-modulating genes (DAT1 9/10 and COMT Val/Met) on n-back working memory performance in healthy volunteers

BACKGROUND

Impairments in working memory are present in many psychiatric illnesses such as attention-deficit hyperactivity disorder (ADHD) and schizophrenia. The dopamine transporter and catechol-O-methyltransferase (COMT) are proteins involved in dopamine clearance and the dopamine system is implicated in the modulation of working memory (WM) processes and neurochemical models of psychiatric diseases. The effects of functional polymorphisms of the dopamine transporter gene (DAT1) and the COMT gene were investigated using a visuospatial and numerical n-back working memory paradigm. Our n-back task was designed to reflect WM alone, and made no demands on higher executive functioning.

METHOD

A total of 291 healthy volunteers (aged 18-45 years) were genotyped and matched for age, sex, and Barratt Impulsivity Scale (BIS) and National Adult Reading Test (NART) scores. To assess individual gene effects on WM, factorial mixed model analysis of variances (ANOVAs) were conducted with the between-subjects factor as genotype and difficulty level (0-, 1-, 2- and 3-back) entered as the within-subjects factor.

RESULTS

The analysis revealed that the DAT1 or COMT genotype alone or in combination did not predict performance on the n-back task in our sample of healthy volunteers.

CONCLUSIONS

Behavioral effects of DAT1 and COMT polymorphisms on WM in healthy volunteers may be non-existent, or too subtle to identify without exceedingly large sample sizes. It is proposed that neuroimaging may provide more powerful means of elucidating the modulatory influences of these polymorphisms.

Structural Stability of Si-O-a-C:H/Si-a-C:H Layered Systems

Amorphous hydrogenated carbon films are of technological interest as protection coatings due to their special properties such as high hardness, chemical inertness, electrical insulation and infrared transparency. However, some applications still suffer from the poor thermal stability and adhesion problems of these coatings. To ensure good adhesion, especially on hardened steels and non-carbide forming substrates, an extra interlayer has to be deposited first. Often a silicon containing interlayer, Si-a-C:H for example, is used for this purpose. This Si-a-C:H interface layer was deposited by rf plasma deposition from tetramethylsilane. Then a-C:H films containing Si-O with a varying silicon content were produced from a mixture of acetylene and hexamethyldisiloxane. The structural changes upon annealing of these films were investigated using Raman spectroscopy. The analysis of the development of the different peaks upon annealing temperature reveals the transition from the amorphous structure to the more graphitic-like structure. This transition temperature increases by as much as 100°C when silicon is incorporated into the DLC film. However, when Si-O is incorporated instead of only silicon the same increase in temperature stability is observed.

High-precision determination of the electric and magnetic form factors of the proton

New precise results of a measurement of the elastic electron-proton scattering cross section performed at the Mainz Microtron MAMI are presented. About 1400 cross sections were measured with negative four-momentum transfers squared up to Q² = 1 (GeV/c)² with statistical errors below 0.2%. The electric and magnetic form factors of the proton were extracted by fits of a large variety of form factor models directly to the cross sections. The form factors show some features at the scale of the pion cloud. The charge and magnetic radii are determined to be <r²E>½ = 0.879(5)stat(4)syst(2)model(4)group fm and <r²M>½ = 0.777(13)stat(9)syst(5)model(2)group fm.

Spinocerebellar ataxia type 17 associated with an expansion of 42 glutamine residues in TATA-box binding protein gene

BACKGROUND

Spinocerebellar ataxia type 17 (SCA17) is caused by abnormal expansions of CAG/CAA trinucleotides within the TATA-box binding protein gene (TBP). The currently accepted critical threshold of abnormal expansions is ≥43.

OBJECTIVE

To investigate the minimal CAG/CAA expansion within the TBP in SCA17.

RESULTS

285 patients with autosomal-dominant ataxia were examined, and abnormal or borderline expansions of CAG/CAA within TBP in eight cases were found. Of those, four patients from three families had exactly 42 CAG/CAA trinucleotides, that is, one codon less than the currently accepted critical threshold of 43. The four patients presented with a relatively benign phenotype. All had dysdiadochokinesia and dysarthria. Mild gait ataxia was observed in three of the four patients.

CONCLUSION

The reference definition of at least 43 CAG/CAA codons for pathological SCA17 alleles should be lowered to 42.

Effects of modafinil and prazosin on cognitive and physiological functions in healthy volunteers

Previous research has demonstrated cognitive-enhancing effects of modafinil in humans and generated evidence for its therapeutic potential in psychiatric disorders. The neurochemical basis of these effects remains unresolved although a role for α1-adrenoceptors has been hypothesised. In this within-subject, double-blind, placebo-controlled study, 12 healthy male adults received modafinil (300 mg), the α1-adrenoceptor antagonist prazosin (3 mg), both together and placebo on separate occasions at least 5 days apart. Cognitive effects were assessed using a well-validated testing battery focusing on executive and working memory functions. Blood pressure, heart rate and salivary α-amylase (sAA) were measured at hourly intervals. Cognitive effects of modafinil and prazosin were identified at the difficult levels of the One-Touch Stockings of Cambridge (OTSOC) planning task. Prazosin antagonized the error-reducing effect of modafinil when the agents were given together. In contrast, the combined agents acted synergistically to increase time taken to complete OTSOC problems compared with placebo. The tachycardic and sAA-elevating effects of prazosin were also potentiated by concurrent modafinil administration. The current data suggest that the cognitive effects of modafinil on performance accuracy and latency are dissociable in terms of their neurochemical mechanisms. Our findings support the hypothesised involvement of α1-adrenoceptors in some of the cognitive-enhancing effects of modafinil and warrant further investigation.