Dynamic behaviour of selected PET tracers in embryonated chicken eggs

Positron emission tomography/computer tomography (PET/CT) is an established method in preclinical research in small animal disease models and the clinical diagnosis of cancer. It combines functional information of the positron-emitting biomarker with the anatomical data obtained from the CT image. Thus, it allows for 4D in vivo investigation of biological processes. Recently, PET/CT was used to monitor bone growth of chicken embryos using (18)F-fluoride as a bone-seeking tracer. We are interested in investigating the adequacy of additional PET/CT tracers in chicken embryos as an in vivo model system. For this reason, we evaluated several positron emitting compounds typically used in clinical tests or if these were not commercially available, we synthesised them. We studied the properties of these (18)F- and (68)Ga-labelled tracers and of (64)Cu-chloride in catheterised eggs via small animal microPET/CT. 2-Deoxy-2-[(18)F]fluoroglucose ([(18)F]FDG) was primarily absorbed at the sites of bone growth. (64)Cu chloride and a (68)Ga-labelled amyloid-fibril-binding antibody accumulated in the liver, while the (68)Ga-albumin desferrioxamine conjugate signal in liver decreased over time. These results indicate that these biomarkers can potentially be used for the monitoring of biological processes in chicken eggs as an animal model.

Survey of users of TOPS, an internet-based system to prevent healthy subjects from over-volunteering for clinical trials

OBJECTIVE

To analyse users' experience of TOPS, an internet-based system that helps UK clinical research units to prevent healthy volunteers from participating in more than one non-therapeutic trial simultaneously, or starting a second trial too soon after the first.

METHODS

We sent to all units that currently use TOPS an anonymous questionnaire comprising 18 questions about the effectiveness and ease of use of the system.

RESULTS

Of 35 units that currently use TOPS, 31 (85.7 %) returned questionnaires. Most users find TOPS easy to use, had increased their detection rate of over-volunteering, and had rejected subjects as a result of using TOPS. A GP reply alone is not enough to prevent over-volunteering. Ethics committees, the MHRA and sponsors know about TOPS and support its use.

CONCLUSIONS

The results confirm that TOPS does prevent healthy subjects from over-volunteering. Consequently, the Health Research Authority has agreed to take over the management of TOPS. Ethics committee approval of a phase 1 trial and MHRA accreditation of the unit will henceforth be conditional on consistent and proper use of TOPS. That should enhance its effectiveness and improve the safety of volunteers in non-therapeutic trials in the UK.

Effect of different orthotic concepts as first line treatment of plantar fasciitis

BACKGROUND

Evaluation of the effectiveness of three different types of prefabricated foot orthotics in the treatment of plantar fasciitis.

METHODS

Prospective, randomized head-to-head trial in 30 adults (21 women, 9 men) with plantar fasciitis without any anatomic alterations. Three different prefabricated orthotics were tested (thin, non supportive orthotic (NO); soft supportive foam orthotic (FO); foam covered rigid self-supporting plastic orthotic (PO)). The follow up was 3 weeks. Main outcome measures were maximum and average pain (VAS), duration of pain per day, walking distance and subjective comfort.

RESULTS

There was no significant effect of NO on maximal pain and average pain. FO and PO had a significant effect on pain levels (p<0.05) whereas PO was superior concerning pain reduction and the time until the onset of effect (p<0.05).

CONCLUSIONS

PO are superior regarding pain reduction and pain free time when compared to FO. NO did not demonstrate a significant effect in the test setup used.

[Technical aspects in the provision of orthopedic shoes for athletes]

From the technical point of view different groups must be distinguished in the provision of orthopedic shoes for athletes. The one group encompasses athletes who are provided with insoles in the hope of improved comfort or better performance. The other group includes athletes with diseases or injuries of the lower limbs for whom the provision of appropriate shoes and insoles makes it possible for them to participate again actively in their chosen sport. In such cases one has to differentiate between the purely physical disorder of the foot and biomechanical disorders. For the first group the correct fitting of the shoe is the most important factor whereas in the second group attempts are made to correct and/or compensate for the deficit by means of insoles and wedges as well as supporting or bedding elements. The particular challenge for all such measures is to achieve an as small as possible impairment on the sport activity or, in the ideal cases, even to support it.

Endstation for ultrafast magnetic scattering experiments at the free-electron laser in Hamburg

An endstation for pump-probe small-angle X-ray scattering (SAXS) experiments at the free-electron laser in Hamburg (FLASH) is presented. The endstation houses a solid-state absorber, optical incoupling for pump-probe experiments, time zero measurement, sample chamber, and detection unit. It can be used at all FLASH beamlines in the whole photon energy range offered by FLASH. The capabilities of the setup are demonstrated by showing the results of resonant magnetic SAXS measurements on cobalt-platinum multilayer samples grown on freestanding Si(3)N(4) membranes and pump-laser-induced grid structures in multilayer samples.

Quantum chemical studies on the enantiomerization mechanism of several [Zn(py)3(tach)]2+ derivatives

The enantiomerization mechanism of the trigonal-prismatic [Zn(py)(3)(tach)](2+) complex and several derivatives has been studied by applying DFT calculations (B3LYP/LANL2DZp). The enantiomerization pathways of [Zn(py(3)tach-X)](2+) (X = C, Si, Ge, N, P, As, O, S and Se) start from a distorted trigonal-prismatic C(3) symmetric ground state via an ideal trigonal-prismatic C(3v) structure to end up in a C(3)' symmetric image of the ground state. The activation energy and structural data of the complexes depend on electronic and steric factors. The activation barriers of the complexes decrease in the order [Zn(py(3)tach-Ge)](2+) > [Zn(py(3)tach-Si)](2+) > [Zn(py(3)tach-As)](2+) > [Zn(py(3)tach-Se)](2+) > [Zn(py(3)tach-P)](2+) > [Zn(py(3)tach-S)](2+) > [Zn(py(3)tach-C)](2+) > [Zn(py(3)tach-N)](2+) > [Zn(py(3)tach-O)](2+).

Reliability of the novel 7-joint ultrasound score: results from an inter- and intraobserver study performed by rheumatologists

OBJECTIVE

To assess the inter- and intraobserver reliability of 26 rheumatologists when performing the 7-joint ultrasound score (US7).

METHODS

Six patients with rheumatoid arthritis were examined by 26 sonographers in 12 rater groups who performed the US7 score. The US7 score includes the clinically dominant wrist, the second and third metacarpophalangeal (MCP) and proximal interphalangeal joints, and the second and fifth metatarsophalangeal (MTP) joints, which were evaluated for synovitis, tenosynovitis/paratenonitis, and erosions from the dorsal side and palmar/plantar aspects by gray-scale and power Doppler (PD) ultrasound. Additional lateral scans were performed at the MCP2 and MTP5 joints. All of the groups repeated the examination in 4 patients in order to calculate the intraobserver reliability. The results of one group that included 2 expert sonographers were considered as the reference standard. Kappa values, median agreement rates (interobserver), and P values (intraobserver evaluation) were calculated.

RESULTS

The median overall kappa value for detecting synovitis was 0.51, for tenosynovitis/paratenonitis was 0.57, and for erosions was 0.45. In detail, the best interobserver results were found for the detection of erosions in the MTP2 joint from the plantar aspect (κ = 1; median agreement rate 89.4%) and for PD signal detection in the palmar wrist region (κ = 0.79; median agreement rate 78.8%). Good agreement was found for detecting erosions in the MCP2 joint from the radial side (κ = 0.67; median agreement rate 77.3%).

CONCLUSION

The inter- and intraobserver reliability of the US7 score shows moderate to substantial kappa values and good agreements. Therefore, this ultrasound score has the potential to be an important imaging tool, including multicenter analysis to assess structural changes.

Killer-cell immunoglobulin-like receptors and malaria caused by Plasmodium falciparum in The Gambia

The relevance of innate immune responses to Plasmodium falciparum infection, in particular the central role of natural killer (NK) cell-derived interferon gamma (IFN-γ), is becoming increasingly recognised. Recently, it has been shown that IFN-γ production in response to P. falciparum antigens is in part regulated by killer-cell immunoglobulin-like receptor (KIR) genes, and a study from malaria-exposed Melanesians suggested an association between KIR genotypes and susceptibility to infection. This prompted us to determine and compare the frequencies of 15 KIR genes in Gambian children presenting with either severe malaria (n = 133) or uncomplicated malaria (n = 188) and in cord-blood population control samples (n = 314) collected from the same area. While no significant differences were observed between severe and uncomplicated cases, proportions of individuals with KIR2DS2+C1 and KIR2DL2+C1 were significantly higher among malaria cases overall than in population control samples. In an exploratory analysis, activating KIR genes KIR2DS2, KIR3DS1 and KIR2DS5 were slightly higher in children in disease subgroups associated with the highest mortality. In addition, our data suggest that homozygosity for KIR genotype A might be associated with different malaria outcomes including protection from infection and higher blood parasitaemia levels in those that do get infected. These findings are consistent with a probable role of KIR genes in determining susceptibility to malaria, and further studies are warranted in different populations.

Structure and dynamics in protic ionic liquids: a combined optical Kerr-effect and dielectric relaxation spectroscopy study

The structure and dynamics of ionic liquids (ILs) are unusual due to the strong interactions between the ions and counter ions. These microscopic properties determine the bulk transport properties critical to applications of ILs such as advanced fuel cells. The terahertz dynamics and slower relaxations of simple alkylammonium nitrate protic ionic liquids (PILs) are here studied using femtosecond optical Kerr-effect spectroscopy, dielectric relaxation spectroscopy, and terahertz time-domain spectroscopy. The observed dynamics give insight into more general liquid behaviour while comparison with glass-forming liquids reveals an underlying power-law decay and relaxation rates suggest supramolecular structure and nanoscale segregation.

TOPS: an internet-based system to prevent healthy subjects from over-volunteering for clinical trials

Aim

Our aim was to set up a system to help UK clinical research units to prevent healthy volunteers from participating in more than one non-therapeutic trial simultaneously, or from starting a second trial too soon after the first.

Methods

TOPS (The Over-volunteering Prevention System) is internet-based, simple and quick to use, free to users and a charity run by a Board of Trustees. Users enter only two or three pieces of information: (1) ‘National Insurance number’ (NINO) of UK citizens, or ‘passport number’ and country of origin of non-UK citizens, as their identifier, (2) ‘date of last dose’ of trial medicine or (3) ‘never dosed’. Subjects must consent, but TOPS collects only non-personal data, so it does not require Ethics Committee approval and is not covered by the Data Protection Act.

Results

A total of 55 research units (29 clinical research organisations, 5 pharmaceutical companies, 13 universities and 8 hospitals) throughout the UK have registered to use TOPS, and have entered 124,906 volunteers since we launched it. All commercial and many non-commercial units now use TOPS. In our unit, no subject has to the best of our knowledge participated in two trials simultaneously. TOPS has reduced to <1% the incidence of subjects attempting to volunteer within 3 months of completing another trial elsewhere, and very few have to our knowledge succeeded.

Conclusion

TOPS is widely used and effective, and helps research units to comply with UK clinical trial regulations.

Time-variant partial directed coherence in analysis of the cardiovascular system. A methodological study

Time-variant partial directed coherence (tvPDC) is used for the first time in a multivariate analysis of heart rate variability (HRV), respiratory movements (RMs) and (systolic) arterial blood pressure. It is shown that respiration-related HRV components which also occur at other frequencies besides the RM frequency (= respiratory sinus arrhythmia, RSA) can be identified. These additional components are known to be an effect of the 'half-the-mean-heart-rate-dilemma' ('cardiac aliasing' CA). These CA components may contaminate the entire frequency range of HRV and can lead to misinterpretation of the RSA analysis. TvPDC analysis of simulated and clinical data (full-term neonates and sedated patients) reveals these contamination effects and, in addition, the respiration-related CA components can be separated from the RSA component and the Traube-Hering-Mayer wave. It can be concluded that tvPDC can be beneficially applied to avoid misinterpretations in HRV analyses as well as to quantify partial correlative interaction properties between RM and RSA.

Near-field signature of electromagnetic coupling in metamaterial arrays: a terahertz microscopy study

Using terahertz near-field imaging we experimentally investigate the interaction between split-ring resonators (SRRs) in metamaterial arrays. Depending on the inter-SRR spacing two regimes can be distinguished for which strong coupling between SRRs occurs. For dense arrays SRRs couple via their electric and magnetic near-fields. In this case distinct deformations of the SRRs' characteristic near-field patterns are observed as a signature of their strong interaction. For larger separations with a periodicity matching the resonance wavelength, the SRRs become diffractively coupled via their radiated fields. In this regime hybridization between plasmonic and lattice modes can be clearly identified in the experimentally obtained near-field maps.

B domain containing Tenascin-C: a new urine marker for surveillance of patients with urothelial carcinoma of the urinary bladder?

BACKGROUND

ECM remodelling during tumorigenesis entails the re-occurrence of different Tn-C(L) splicing variants. In patients with urothelial carcinoma of the urinary bladder (UBC), B and C domain containing Tenascin-C (B(+) and C(+) Tn-C) urine levels were shown to be increased in case of muscle invasiveness. Thus, the present study was aimed at examining the ability of B(+) and C(+) Tn-C as potential urinary surveillance markers of UBC patients.

METHODS

Urine levels of B(+) and C(+) Tn-C were determined by ELISA in 35 UBC patients during a 2 year follow-up period after therapy and related to clinical diagnosis and histological stage in 4 defined groups representing typical courses of disease.

RESULTS

B(+) Tn-C levels showed significant differences between cases of tumour progression or regression. The urine levels of B(+) Tn-C could be used to discriminate between cases without tumour recurrence and such with tumour existence (cut-off value: 0.8 ng/ml) or between non-muscle invasive and muscle invasive tumour growth (cut-off value: 3.5 ng/ml).

CONCLUSIONS

Progression of UBC with time is accompanied by significant changes in urinary levels of B(+) Tn-C. Urinary B(+) Tn-C can therefore be suggested as a valuable urine surveillance marker in UBC follow-up care.

Suspended core subwavelength fibers: towards practical designs for low-loss terahertz guidance

In this work we report two designs of subwavelength fibers packaged for practical terahertz wave guiding. We describe fabrication, modeling and characterization of microstructured polymer fibers featuring a subwavelength-size core suspended in the middle of a large porous outer cladding. This design allows convenient handling of the subwavelength fibers without distorting their modal profile. Additionally, the air-tight porous cladding serves as a natural enclosure for the fiber core, thus avoiding the need for a bulky external enclosure for humidity-purged atmosphere. Fibers of 5 mm and 3 mm in outer diameters with a 150 µm suspended solid core and a 900 µm suspended porous core respectively, were obtained by utilizing a combination of drilling and stacking techniques. Characterization of the fiber optical properties and the subwavelength imaging of the guided modes were performed using a terahertz near-field microscopy setup. Near-field imaging of the modal profiles at the fiber output confirmed the effectively single-mode behavior of such waveguides. The suspended core fibers exhibit transmission from 0.10 THz to 0.27 THz (larger core), and from 0.25 THz to 0.51 THz (smaller core). Due to the large fraction of power that is guided in the holey cladding, fiber propagation losses as low as 0.02 cm(-1) are demonstrated specifically for the small core fiber. Low-loss guidance combined with the core isolated from environmental perturbations make these all-dielectric fibers suitable for practical terahertz imaging and sensing applications.

unneling effects in InAs/GaInSb superlattice infrared photodiodes

The optical and electrical properties of InAs/GaInSb superlattice mesa photodiodes with a cutoff wavelength around 8 pim are investigated. The influence of the surface potential at the mesa sidewalls on the device properties was studied by fabricating gate-controlled diodes. At least two mechanisms determining the dark current in the reverse bias region can be identified. At high reverse biases bulk bandto- band tunneling dominates while the current at low reverse biases is most likely governed by surface effects. Bulk interband tunneling is further investigated by applying magnetic fields B up to 7 T parallel and perpendicular to the electric field E across the p-n junction.

Terahertz near-field microscopy of complementary planar metamaterials: Babinet's principle

Using terahertz near-field imaging we experimentally investigate the resonant electromagnetic field distributions behind a split-ring resonator and its complementary structure with sub-wavelength spatial resolution. For the out-of-plane components we experimentally verify complementarity of electric and magnetic fields as predicted by Babinet's principle. This duality of near-fields can be used to indirectly map resonant magnetic fields close to metallic microstructures by measuring the electric fields close to their complementary analogues which is particularly useful since magnetic near-fields are still extremely difficult to access in the THz regime. We find excellent agreement between the results from theory, simulation and two different experimental near-field techniques.

Technical note: Terahertz imaging of ancient mummies and bone

Ancient mummified soft-tissues are a unique source to study the evolution of disease. Diagnostic imaging of such historic tissues is of foremost interest in paleoanthropology or paleopathology, with conventional x-ray and computed tomography (CT) being the gold-standard. Longer wavelength radiation in the far-infrared or Terahertz region allows diagnostic close-to-surface tissue differentiation of bone morphology while being harmless to human cells. The aim of this study is to show the feasibility and the morpho-diagnostic impact of THz imaging of historic remains. Images of an artificially embalmed ancient Egyptian human mummy hand, an artificially embalmed ancient Egyptian mummified fish and a macerated human lumbar vertebra were obtained by THz-pulse imaging and compared with conventional X-ray and CT images. Although conventional x-ray imaging provides higher spatial resolution, we found that THz-imaging is well-suited for the investigation of ancient mummified soft tissue and embalming-related substances / wrappings. In particular, bone and cartilaginous structures can be well differentiated from surrounding soft-tissues and bandage-wrappings by THz imaging. Furthermore, THz-pulse imaging also measures the time-delay of the pulsed signal when passing through the sample, which provides supplementary information on the optical density of the sample that is not obtained by X-ray and CT. Terahertz radiation provides a completely non-invasive diagnostic imaging modality for historic dry specimens. We anticipate this modality also to be used for detection of hidden objects in historic samples such as funerary amulets still in situ in wrapped mummies, as well as potentially for the identification of spectral signatures from chemical substances, e.g., in embalming essences.

Terahertz near-field microscopy with subwavelength spatial resolution based on photoconductive antennas

Imaging and sensing applications based on pulsed terahertz radiation have opened new possibilities for scientific and industrial applications. Many exploit the unique features of the terahertz (THz) spectral region, where common packaging materials are transparent and many chemical compounds show characteristic absorptions. Because of their diffraction limit, THz far-field imaging techniques lack microscopic resolution and, if subwavelength features have to be resolved, near-field techniques are required. Here, we present a THz near-field microscopy approach based on photoconductive antennas as the THz emitter and as a near-field probe. Our system allows us to measure amplitude, phase, and polarization of the electric fields in the vicinity of a sample with a spatial resolution on the micrometer scale (approximately lambda/20). Using a dielectric (plant leaf) and a metallic structure (microwire) as examples, we demonstrate the capabilities of our approach.

Spectral collapse in ensembles of metamolecules

We report on the first direct experimental demonstration of a collective phenomenon in metamaterials: spectral line collapse with an increasing number of unit cell resonators (metamolecules). This effect, which is crucial for achieving a lasing spaser, a coherent source of optical radiation fuelled by coherent plasmonic oscillations in metamaterials, is linked to the suppression of radiation losses in periodic arrays. We experimentally demonstrate spectral line collapse at microwave, terahertz and optical frequencies.

Lattice modes mediate radiative coupling in metamaterial arrays

We show that a resonant response with very high quality factors can be achieved in periodic metamaterials by radiatively coupling their structural elements. The coupling is mediated by lattice modes and can be efficiently controlled by tuning the lattice periodicity. Using a recently developed terahertz (THz) near-field imaging technique and conventional far-field spectroscopy together with numerical simulations we pinpoint the underlying mechanisms. In the strong coupling regimes we identify avoided crossings between the plasmonic eigenmodes and the diffractive lattice modes.

[Implementation of standardized postoperative pain therapy for orthopaedic patients. Comparison between unsystematic and standardized pain therapy]

BACKGROUND

The painless clinic and postoperative pain therapy are currently major issues in the management of surgical procedures. The aim of this study was to evaluate the benefit of a standardized pain therapy on the postoperative pain level after orthopaedic procedures.

PATIENTS AND METHODS

We investigated two different groups of patients who underwent an orthopaedic surgical procedure. Group 1 (n = 249) received a pain therapy which was based on an individual and surgery-dependent concept whereas group 2 (n = 243) was treated with a standardized pain therapy concept. The effect of the treatment was monitored with a VAS-based protocol.

RESULTS

Up to day 9 after surgery there was a significant difference between the two groups in regard to the postoperative pain. The patients of group 2 had less pain but had more unwanted side effects caused by the pain therapy during the first 3 days after surgery. Mobility and mental disposition were positively affected.

CONCLUSION

The implementation of a standardized pain therapy is successful in reducing postoperative pain. Mobility and mental disposition are also influenced positively. As a consequence the incidence of unwanted side effects is rising.

Terahertz two-photon quantum well infrared photodetector

A two-photon detector based on intersubband transitions in GaAs/AlGaAs quantum wells operating in the Terahertz regime below the Reststrahlenband is reported. Resonantly enhanced optical nonlinearities enables sensitive quadratic detection at pJ pulse energies. We demonstrate its use in a quadratic autocorrelator for far-infrared picosecond pulses at around 7 THz.