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.

Risk factors for renal insufficiency in children with urethral valves

Posterior urethral valves (PUV) associated with renal dysplasia are one of the most common causes of end stage kidney disease (ESKD) in childhood. In order to identify risk factors for the progression of this condition to early renal failure, we have retrospectively analyzed the clinical course, renal function, and first postnatal renal ultrasound in a sample of 42 young male patients with PUV, who were followed at a single center. Twelve (28.6%) were diagnosed with ESKD at a median age of 11.3 years. Our comparison of PUV patients without decreased estimated glomerular filtration rate (eGFR) (group A; K/DOQI CKD stage 0-1) with PUV patients showing a decreased eGFR (group B; K/DOQI CKD stage 2-5) revealed the following significant risk factors for loss of eGFR: renal volume <3rd percentile (P < 0.001), elevated echogenicity (P = 0.001), pathologic corticomedullary differentiation (P < 0.001), >3 febrile urinary tract infections (P = 0.012), and decreased eGFR at 1 year of age (P < 0.001). Receiver operating characteristic curve analysis in the cohort confirms that patients showing a renal volume >88.2 ml/m(2) body surface area (BSA) are not at risk to develop K/DOQI CKD stage 5 (sensitivity 75%, specificity 77.3%, positive/negative predictive value 37.5/94.4%). Ultrasound promises to be a valuable tool for identifying endangered patients.

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.

Prevalence of hepatitis E virus-specific antibodies in humans with occupational exposure to pigs

Due to the increasing number of non-travel-associated hepatitis E virus (HEV) infections observed in several industrialised countries including Germany, there is a substantial interest in the characterisation of risk factors and transmission routes relevant to autochthonous HEV infections. Autochthonous cases are believed to be the result of a zoonotic HEV transmission from pigs, wild boars and deer. Recently, a high prevalence of HEV-specific antibodies in the German domestic pig population has been demonstrated. Thus, one may assume a higher prevalence of HEV-specific antibodies in humans with occupational exposure to pigs. In this study, sera obtained from 24 slaughterers, 14 meat inspectors, 46 pig farmers and 22 veterinarians were tested for the presence of HEV-specific antibodies using a line immunoassay. For comparison, sera obtained from 116 age- and gender-matched blood donors were also included. Twenty eight per cent (28.3%; 30/106) of the swine-exposed humans and 15.5% (18/116) of the blood donors without contact to pigs exhibited IgG-antibodies determined as reactive (i.e. borderline or positive) against HEV. Thus, an increased risk of HEV infection in humans occupationally exposed to pigs and particularly for slaughterers (41.7%; 10/24) was demonstrated.

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.

Comparison of the orthonasal and retronasal detection thresholds for carbon dioxide in humans

Several studies have investigated the orthonasal detection threshold for carbon dioxide (CO(2)) in humans. The aim of current study was to investigate whether 24 healthy young subjects exhibited differences of CO(2) detection thresholds during orthonasal or retronasal stimulation. As nasal mucosa is believed to desensitize to CO(2) concentrations at or below 4% (v/v) during expiration, the second aim of the study was to explore the influence during nasal versus oral breathing on the detection thresholds. CO(2) stimuli of varying concentrations and a duration of 1000 ms were applied with an air-dilution olfactometer in either the anterior nasal cavity or the nasopharynx during nasal respectively oral breathing. In these 4 conditions, the mean CO(2) detection thresholds using the staircase forced-choice procedure were between 3.9% and 5.3% (v/v). Statistical analysis revealed a significant difference between orthonasal and retronasal stimulation. The CO(2) detection threshold was lower in retronasal stimulation. The nasopharyngeal mucosa is more sensitive to perithreshold CO(2) stimuli than the nasal mucosa. The breathing route had no influence on the detection thresholds. The results of this study indicate that the natural contact of the nasal mucosa with approximately 4% (v/v) CO(2) during nasal expiration does not influence CO(2) detection thresholds.

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.

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.

[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.

Structural basis for pH-dependent alterations of reaction specificity of vertebrate lipoxygenase isoforms

Lipoxygenases have been classified according to their specificity of fatty acid oxygenation and for several plant enzymes pH-dependent alterations in the product patterns have been reported. Assuming that the biological role of mammalian lipoxygenases is based on the formation of specific reaction products, pH-dependent alterations would impact enzymes' functionality. In this study we systematically investigated the pH-dependence of vertebrate lipoxygenases and observed a remarkable stability of the product pattern in the near physiological range for the wild-type enzyme species. Site-directed mutagenesis of selected amino acids and alterations in the substrate concentrations induced a more pronounced pH-dependence of the reaction specificity. For instance, for the V603H mutant of the human 15-lipoxygenase-2 8-lipoxygenation was dominant at acidic pH (65%) whereas 15-H(p)ETE was the major oxygenation product at pH 8. Similarly, the product pattern of the wild-type mouse 8-lipoxygenase was hardly altered in the near physiological pH range but H604F exchange induced strong pH-dependent alterations in the positional specificity. Taken together, our data suggest that the reaction specificities of wild-type vertebrate lipoxygenase isoforms are largely resistant towards pH alterations. However, we found that changes in the assay conditions (low substrate concentration) and introduction/removal of a critical histidine at the active site impact the pH-dependence of reaction specificity for some lipoxygenase isoforms.