Algorithm development for low level radioxenon 2D spectra analysis: A first case of study using spectral unmixing for a β-γ detector

In the scope of the verification regime of the Comprehensive nuclear Test Ban Treaty, the CEA/DAM is developing new β-γ measurement systems. In order to improve the analysis methods at low statistics, a new multiplicative spectral unmixing algorithm for full-spectrum analysis was tested on a particular setup for different types of mixtures. The reconstructed activities for simulated spectra and the characteristic limits found with this algorithm are compared to the classic ROI analysis method.

The critical need to accelerate cerebral palsy research with consumer engagement, global networks, and adaptive designs

The prevalence of cerebral palsy (CP) varies globally, with higher rates and burden of disease in low- and middle-income countries. CP is a lifelong condition with no cure, presenting diverse challenges such as motor impairment, epilepsy, and mental health disorders. Research progress has been made but more is needed, especially given consumer demands for faster advancements and improvements in the scientific evidence base for interventions. This paper explores three strategies to accelerate CP research: consumer engagement, global clinical trial networks, and adaptive designs. Consumer engagement involving individuals with lived experience enhances research outcomes. Global clinical trial networks provide efficiency through larger and more diverse participant pools. Adaptive designs, unlike traditional randomized controlled trials, allow real-time modifications based on interim analyses, potentially answering complex questions more efficiently. The establishment of a CP Global Clinical Trials Network, integrating consumer engagement, global collaboration, and adaptive designs, marks a paradigm shift. The Network aims to address consumer-set research priorities. While challenges like ethical considerations and capacity building exist, the potential benefits for consumers, clinicians, researchers, and funding bodies are substantial. This paper underscores the urgency of transforming CP research methodologies for quicker translation of novel treatments into clinical practice to improve quality of life for those with CP.

Uncertainties regarding cerebral palsy diagnosis: opportunities to operationalize the consensus definition

Background and Objectives

Cerebral palsy (CP), the most common motor disability of childhood, is variably diagnosed. We hypothesized that child neurologists and neurodevelopmentalists, often on the frontlines of CP diagnosis in North America, harbor uncertainties regarding the practical application of the most recent CP consensus definition from 2006.

Methods

We conducted a cross-sectional survey of child neurologists and neurodevelopmentalists at the 2022 Child Neurology Society Annual Meeting. Attendees were provided the 2006 CP consensus definition and asked whether they had any uncertainties about the practical application of the definition across four hypothetical clinical vignettes.

Results

Of 230 attendees, 164 responded to the closing survey questions (71%). 145/164 (88%) expressed at least one uncertainty regarding the clinical application of the 2006 definition. Overwhelmingly, these areas of uncertainty focused on: 1) Age, both with regards to the minimum age of diagnosis and the maximum age of brain disturbance or motor symptom onset, (67/164, 41%), and 2) Interpretation of the term "non-progressive" (48/164, 29%). The vast majority of respondents (157/164, 96%) answered 'Yes' to the question: Do you think we should revise the 2006 consensus definition of CP?

Discussion

We propose that the uncertainties we identified could be addressed by operationalizing the 2006 consensus definition to support a more uniform CP diagnosis. To address the most common CP diagnostic uncertainties we identified, we propose 3 points of clarification based on the available literature: 1) Motor symptoms/signs should be present by 2 years old; 2) CP can and should be diagnosed as early as possible, even if activity limitation is not yet present, if motor symptoms/signs can be reasonably predicted to yield activity limitation (e.g. by using standardized examination instruments, Brain MRI, and a suggestive clinical history); and 3) The clinical motor disability phenotype should be non-progressive through 5 years old. We anticipate that operationalizing the 2006 definition of CP in this manner could clarify the uncertainties we identified among child neurologists and neurodevelopmentalists and reduce the diagnostic variability that currently exists.

Epilepsy and proxy-reported health-related quality of life in children and young people with non-ambulatory cerebral palsy

AIM

To assess the association between epilepsy characteristics and proxy-reported health-related quality of life (HRQoL) in children and young people with non-ambulatory cerebral palsy (CP) and seizures.

METHOD

This was a cross-sectional study of 164 children and young people (74 females, 90 males; mean age 10 years 6 months, range 2-21 years, SD 5 years 5 months). Caregivers completed the Child Health Index of Life with Disabilities (CPCHILD) in an outpatient setting. We utilized univariable linear regression and multivariable modeling to study relationships between variables and CPCHILD scores.

RESULTS

Gross Motor Function Classification System levels were 37% IV and 63% V. Sociodemographic factors included the Child Opportunity Index (median 51, interquartile range [IQR] 25-80). A median of 2 (IQR 1-3) antiseizure medications (ASMs) were used, and days with seizures ranged from 0 (30%) to 28 (20%) days in the previous 4 weeks. Total CPCHILD scores decreased 2.3 points for each ASM (95% confidence interval [CI] -4.1 to -0.42). Compared to persons with focal epilepsy, those with generalized epilepsy had lower total CPCHILD scores (-5.7; 95% CI -11 to -0.55). Number of days with seizures was not associated with total CPCHILD scores.

INTERPRETATION

Proxy-reported HRQoL was affected by epilepsy-specific features in children and young people with severe CP.

WHAT THIS PAPER ADDS

Health-related quality of life (HRQoL) was lower with increasing numbers of antiseizure medications. Overall quality of life (QoL) scores were lower by a similar amount, independent of seizure frequency. HRQoL was lower in persons with recent hospital admissions for epilepsy.

Establishing ranked priorities for future hydrocephalus research

OBJECTIVE

The aim of this initiative was to develop a ranked list of hydrocephalus research priorities as determined by the hydrocephalus patient community in conjunction with the healthcare and scientific community.

METHODS

Using the validated methodology published by the James Lind Alliance (JLA), the Hydrocephalus Association (HA) administered two surveys and hosted a final prioritization workshop. Survey One solicited open-ended responses from the community. From these responses, a long list of priority statements was developed. This list was then consolidated into a short list of research priority statements, which, after a nonsystematic literature review, were verified as being research uncertainties. Survey Two asked the community members to select their top 10 priorities from the short list. The final prioritization leading to a final ranked top 20 list of hydrocephalus research priorities took place at a virtual workshop led by a team of trained facilitators, by means of an iterative process of consensus building.

RESULTS

From Survey One, 3703 responses from 890 respondents were collected, leading to a long list of 146 priority statements. The consolidated short list contained 49 research priority statements, all of which were verified as uncertainties in hydrocephalus research. From an analysis of Survey Two responses, the top 21 research priority statements were determined. A consensus on these statements was reached at the virtual workshop, leading to a final ranked top 20 list of hydrocephalus research priorities, within which needs were apparent in several areas: development of noninvasive and/or one-time therapies, reduction of the burden of current treatments, improvement of the screening and diagnosis of hydrocephalus, improved quality of life, and improved access to care.

CONCLUSIONS

By gathering extensive input from the hydrocephalus community and using an iterative process of consensus building, a ranked list of the top 20 hydrocephalus research priorities was developed. The HA will use this ranked list to guide future research programs and encourages the healthcare and scientific community to do the same.

Top 10 Research Themes for Dystonia in Cerebral Palsy: A Community-Driven Research Agenda

Dystonia in cerebral palsy (DCP) is a common, debilitating, but understudied condition. The CP community (people with CP and caregivers) is uniquely equipped to help determine the research questions that best address their needs. We developed a community-driven DCP research agenda using the well-established James Lind Alliance methodology. CP community members, researchers, and clinicians were recruited through multiple advocacy, research, and professional organizations. To ensure shared baseline knowledge, participants watched webinars outlining our current knowledge on DCP prepared by a Steering Group of field experts (cprn.org/research-cp-dystonia-edition). Participants next submitted their remaining uncertainties about DCP. These were vetted by the Steering Group and consolidated to eliminate redundancy to generate a list of unique uncertainties, which were then prioritized by the participants. The top-prioritized uncertainties were aggregated into themes through iterative consensus-building discussions within the Steering Group. 166 webinar viewers generated 67 unique uncertainties. 29 uncertainties (17 generated by community members) were prioritized higher than their randomly matched pairs. These were coalesced into the following top 10 DCP research themes: (1) develop new treatments; (2) assess rehabilitation, psychological, and environmental management approaches; (3) compare effectiveness of current treatments; (4) improve diagnosis and severity assessments; (5) assess the effect of mixed tone (spasticity and dystonia) in outcomes and approaches; (6) assess predictors of treatment responsiveness; (7) identify pathophysiologic mechanisms; (8) characterize the natural history; (9) determine the best treatments for pain; and (10) increase family awareness. This community-driven research agenda reflects the concerns most important to the community, both in perception and in practice. We therefore encourage future DCP research to center around these themes. Furthermore, noting that community members (not clinicians or researchers) generated the majority of top-prioritized uncertainties, our results highlight the important contributions community members can make to research agendas, even beyond DCP.

Diagnostic preferences include discussion of etiology for adults with cerebral palsy and their caregivers

AIM

To determine the views of individuals with cerebral palsy (CP) and their caregivers (CP community members) about carrying a CP diagnosis, an etiological diagnosis, or both diagnoses together.

METHOD

We surveyed CP community members across two registries querying their views on carrying a CP diagnosis, one type of etiological diagnosis (specifically, a genetic diagnosis), or both. Open-ended responses were analyzed using a conventional content analysis approach.

RESULTS

Of 197 respondents (108 adults with CP and 89 caregivers), most (75%) valued knowing the cause of their CP. Of those with a diagnostic preference, most preferred carrying both CP and etiological diagnoses together (68%). When compared with carrying an etiological diagnosis alone, significantly more respondents felt a CP diagnosis helped anticipate symptom evolution (84% vs 54%), explain symptoms to others (86% vs 48%), access services (86% vs 48%), and join support communities (78% vs 50%) (p <  0.01, χ² test).

INTERPRETATION

Most CP community members surveyed want to know the cause of their CP and would prefer carrying both CP and etiological diagnoses together. Clinical practice should evolve to meet these community needs.

Anterior versus posterior entry site for ventriculoperitoneal shunt insertion: a randomized controlled trial by the Hydrocephalus Clinical Research Network

OBJECTIVE

The primary objective of this trial was to determine if shunt entry site affects the risk of shunt failure.

METHODS

The authors performed a parallel-design randomized controlled trial with an equal allocation of patients who received shunt placement via the anterior entry site and patients who received shunt placement via the posterior entry site. All patients were children with symptoms or signs of hydrocephalus and ventriculomegaly. Patients were ineligible if they had a prior history of shunt insertion. Patients received a ventriculoperitoneal shunt after randomization; randomization was stratified by surgeon. The primary outcome was shunt failure. The planned minimum follow-up was 18 months. The trial was designed to achieve high power to detect a 10% or greater absolute difference in the shunt failure rate at 1 year. An independent, blinded adjudication committee determined eligibility and the primary outcome. The study was conducted by the Hydrocephalus Clinical Research Network.

RESULTS

The study randomized 467 pediatric patients at 14 tertiary care pediatric hospitals in North America from April 2015 to January 2019. The adjudication committee, blinded to intervention, excluded 7 patients in each group for not meeting the study inclusion criteria. For the primary analysis, there were 229 patients in the posterior group and 224 patients in the anterior group. The median patient age was 1.3 months, and the most common etiologies of hydrocephalus were postintraventricular hemorrhage secondary to prematurity (32.7%), myelomeningocele (16.8%), and aqueductal stenosis (10.8%). There was no significant difference in the time to shunt failure between the entry sites (log-rank test, stratified by age < 6 months and ≥ 6 months; p = 0.061). The hazard ratio (HR) of a posterior shunt relative to an anterior shunt was calculated using a univariable Cox regression model and was nonsignificant (HR 1.35, 95% CI, 0.98-1.85; p = 0.062). No significant difference was found between entry sites for the surgery duration, number of ventricular catheter passes, ventricular catheter location, and hospital length of stay. There were no significant differences between entry sites for intraoperative complications, postoperative CSF leaks, pseudomeningoceles, shunt infections, skull fractures, postoperative seizures, new-onset epilepsy, or intracranial hemorrhages.

CONCLUSIONS

This randomized controlled trial comparing the anterior and posterior shunt entry sites has demonstrated no significant difference in the time to shunt failure. Anterior and posterior entry site surgeries were found to have similar outcomes and similar complication rates.

Low-level laboratory measurement of xenon radionuclides: Electron-photon versus photon measurements

Radioactive xenon (mainly ^131mXe, ¹³³Xe, ^133mXe and ¹³⁵Xe) are tracked as markers of nuclear weapons testing. The CEA has developed the PIPSBox, a measurement cell able to detect electrons emitted by xenon nuclides. Combined with an ultra-low background γ spectrometer, electron detection capacities allow reaching minimum detectable activities (MDA) for a 3-day long measurement of about 0.5mBq for the four xenon radionuclides. Compared to a classical measurement cell, MDAs are improved by a factor of 2-4.

Ground surface ultralow background spectrometer: Active shielding improvements and coincidence measurements for the Gamma3 spectrometer

The ultralow background versatile spectrometer GAMMA³ has been optimized with the following shielding improvements: (i) optimized nitrogen injection flux of 300Lh^-1, and (ii) cosmic veto configuration with 9 scintillating plates. These improvements allow a reduction of 39% of the normalized integral background count rate down to 2.7±0.2min^-1kg_Ge^-1 (40-2500keV energy range). Minimum Detectable Activities when performing direct γ-ray spectrometry or γ-γ coincidence spectrometry are compared.

Getting Started: A Call for Storytelling in Family Medicine Education

In this article we introduce family medicine educators to storytelling as an important teaching tool. We describe how stories are a critical part of the work of family physicians. We review the rationales for family medicine educators to become skilled storytellers. We present the components of effective stories, proposing two different perspectives on how to imagine, construct, and present them. We provide a list of resources for getting started in storytelling and offer two personal vignettes that articulate the importance of storytelling in the authors' respective professional developments. We point the way forward for family medicine educators interested in integrating storytelling into their repertoire of teaching skills.

Report of a workshop on research gaps in the treatment of cerebral palsy

Cerebral palsy (CP) is heterogeneous in etiology and manifestations, making research into relevant therapies difficult and limiting the generalizability of the results. We report here on the NIH CP symposium, where stakeholders from academic, clinical, regulatory, and advocacy backgrounds discussed the major challenges and needs for moving forward with clinical research in CP, and outlined priorities and action items. New information is constantly generated through research into pathogenesis and etiology. Clinical research and new therapeutic approaches need to keep pace, through large data registry integration and new research designs. Development of standardized data collection, increasing academic focus on CP research, and iterative approaches to treatment throughout the patients' lives, have all been identified as areas of focus. The workshop identified critical gaps and areas of focus to increase the evidence base for therapeutic approaches to determine which treatments work best for which patients in the near future. These include consolidation and optimization of databases and registries, updates to the research methodology, and better integration of resources and stakeholders.

Cerebral palsy research funding from the National Institutes of Health, 2001 to 2013

AIM

Cerebral palsy (CP) is a poorly understood disorder with no cure. We determined the landscape of National Institutes of Health (NIH) funding for CP-related research.

METHOD

We searched NIH databases Research Portfolio Online Reporting Tools Expenditures and Results, and Research, Condition, and Disease Categorization for keywords 'cerebral palsy' among all NIH-funded studies, 2001 to 2013. We classified grants by type and area of study.

RESULTS

NIH funding, averaging $30 million per year, supported clinical ($215 million), basic ($187 million), and translational ($26.3 million) CP-related research. Clinical intervention studies comprised 19% of funding, and focused on treatments ($60.3 million), early parent intervention ($2.7 million), and CP prevention ($2.5 million). Among grants that specified gestational age, more funds were devoted to preterm ($166 million) than term infants ($15 million). CP in adulthood was the main focus of 4% of all funding. Annual NIH funding for CP increased steadily over the study period from $3.6 to $66.7 million. However, funding for clinical intervention studies peaked in 2008, and has since decreased.

INTERPRETATION

Additional research funds are needed to improve the treatment and prevention of CP. Topics that have been relatively underfunded include clinical interventions, prevention, and term infants and adults with CP.

On the use of (127)Xe standards for the quality control of CTBTO noble gas stations and support laboratories

(127)Xe has a longer half-life than (131m)Xe, it can be easily purely produced and it is present in the environment at very low level. For these reasons, (127)Xe is supposed to be a convenient quality control radionuclide for remote noble gas stations of the International Monitoring System (IMS) network. As CEA/DAM has recently developed two new photon/electron setups for low-level detection of (131m)Xe, (133m)Xe, (133)Xe and (135)Xe, we took the opportunity to test these setups for the measurement of a (127)Xe standard. The results and a detailed description of these measurements are presented in this paper. They illustrate the complexity of (127)Xe decay, emitting simultaneously several γ, X-rays, conversion electrons and Auger electrons; this results in highly summated coincidence spectra. The measurements performed provide precise electron energy calibration of the setups. The count rate of electrons in coincidence with iodine Kα X-rays was found to be surprisingly low, leading to the study of electron-gated photon spectrum. Finally, a comparison of three photon/electron coincidence spectra obtained with three different setups is given. The use of (127)Xe as a standard for energy calibration of IMS noble gas station is possible, but it appears to be quite complicated for efficiency check of noble gas station equipped with β/γ detectors.

Hydrocephalus research funding from the National Institutes of Health: a 10-year perspective

OBJECT

Funding of hydrocephalus research is important to the advancement of the field. The goal of this paper is to describe the funding of hydrocephalus research from the National Institutes of Health (NIH) over a recent 10-year period.

METHODS

The NIH online database RePORT (Research Portfolio Online Reporting Tools) was searched using the key word "hydrocephalus." Studies were sorted by relevance to hydrocephalus. The authors analyzed funding by institute, grant type, and scientific approach over time.

RESULTS

Over $54 million was awarded to 59 grantees for 66 unique hydrocephalus proposals from 48 institutions from 2002 to 2011. The largest sources of funding were the National Institute of Neurological Disease and Stroke and the National Institute of Child Health and Human Development. Of the total, $22 million went to clinical trials, $15 million to basic science, and $10 million to joint ventures with small business (Small Business Innovation Research or Small Business Technology Transfer). Annual funding varied from $2.3 to $8.1 million and steadily increased in the second half of the observation period. The number of new grants also went from 15 in the first 5 years to 27 in the second 5 years. A large portion of the funding has been for clinical trials. Funding for shunt-device development grew substantially. Support for training of hydrocephalus investigators has been low.

CONCLUSIONS

Hydrocephalus research funding is low compared with that for other conditions of similar health care burden. In addition to NIH applications, researchers should pursue other funding sources. Small business collaborations appear to present an opportunity for appropriate projects.

Improvements of low-level radioxenon detection sensitivity by a state-of-the art coincidence setup

The ability to quantify isotopic ratios of 135, 133 m, 133 and 131 m radioxenon is essential for the verification of the Comprehensive Nuclear-Test Ban Treaty (CTBT). In order to improve detection limits, CEA has developed a new on-site setup using photon/electron coincidence (Le Petit et al., 2013. J. Radioanal. Nucl. Chem., DOI : 10.1007/s 10697-013-2525-8.). Alternatively, the electron detection cell equipped with large silicon chips (PIPS) can be used with HPGe detector for laboratory analysis purpose. This setup allows the measurement of β/γ coincidences for the detection of (133)Xe and (135)Xe; and K-shell Conversion Electrons (K-CE)/X-ray coincidences for the detection of (131m)Xe, (133m)Xe and (133)Xe as well. Good energy resolution of 11 keV at 130 keV and low energy threshold of 29 keV for the electron detection were obtained. This provides direct discrimination between K-CE from (133)Xe, (133m)Xe and (131m)Xe. Estimation of Minimum Detectable Activity (MDA) for (131m)Xe is in the order of 1mBq over a 4 day measurement. An analysis of an environmental radioxenon sample using this method is shown.

Long-term performances of the ⁹⁵ZR/⁹⁵Nb chronometer for nuclear events dating

The present work reports on a long-term analysis of the performances of the (95)Zr/(95)Nb chronometer for dating a nuclear event. Taking benefit of a recent Profiency Test Exercise, a sample containing a standardized mixture of fission products has been measured repeatedly with a low background HPGe spectrometer during a period extending up to one year with the aim of assessing the accuracy of the various zero-time determinations. Evaluation of the uncertainties associated to these evaluations was performed using a Monte Carlo approach. Input parameters sensitivity has been investigated, especially the influence of the (95m)Nb decay branch. The (95)Zr/(95)Nb chronometer was found to be accurate for zero-time determination within one day and one week for a decay of 3 months and 10 months respectively. Sub-day uncertainties are achievable for a two months old sample whereas sub-week uncertainties are reached after a decay of six months. Limitations of the technique for dating a real event are investigated.

Innovative concept for a major breakthrough in atmospheric radioactive xenon detection for nuclear explosion monitoring

The verification regime of the comprehensive test ban treaty (CTBT) is based on a network of three different waveform technologies together with global monitoring of aerosols and noble gas in order to detect, locate and identify a nuclear weapon explosion down to 1 kt TNT equivalent. In case of a low intensity underground or underwater nuclear explosion, it appears that only radioactive gases, especially the noble gas which are difficult to contain, will allow identification of weak yield nuclear tests. Four radioactive xenon isotopes, ^131mXe, ^133mXe, ¹³³Xe and ¹³⁵Xe, are sufficiently produced in fission reactions and exhibit suitable half-lives and radiation emissions to be detected in atmosphere at low level far away from the release site. Four different monitoring CTBT systems, ARIX, ARSA, SAUNA, and SPALAX™ have been developed in order to sample and to measure them with high sensitivity. The latest developed by the French Atomic Energy Commission (CEA) is likely to be drastically improved in detection sensitivity (especially for the metastable isotopes) through a higher sampling rate, when equipped with a new conversion electron (CE)/X-ray coincidence spectrometer. This new spectrometer is based on two combined detectors, both exhibiting very low radioactive background: a well-type NaI(Tl) detector for photon detection surrounding a gas cell equipped with two large passivated implanted planar silicon chips for electron detection. It is characterized by a low electron energy threshold and a much better energy resolution for the CE than those usually measured with the existing CTBT equipments. Furthermore, the compact geometry of the spectrometer provides high efficiency for X-ray and for CE associated to the decay modes of the four relevant radioxenons. The paper focus on the design of this new spectrometer and presents spectroscopic performances of a prototype based on recent results achieved from both radioactive xenon standards and air sample measurements. Major improvements in detection sensitivity have been reached and quantified, especially for metastable radioactive isotopes ^131mXe and ^133mXe with a gain in minimum detectable activity (about 2 × 10⁻³ Bq) relative to current CTBT SPALAX™ system (air sampling frequency normalized to 8 h) of about 70 and 30 respectively.

Effect of thiazolidinedione treatment on proteinuria and renal hemodynamic in type 2 diabetic patients with overt nephropathy

Proteinuria in diabetic nephropathy predicts the progressive loss of glomerular filtration rate (GFR) and serves as independent predictor for mortality. We performed the present study (ClinicalTrials.gov identifier: NCT 00324675) to clarify whether the activation of PPARγ receptor by thiazolidinediones was able to improve proteinuria and preserve renal function in advanced diabetic nephropathy. A total of 28 type 2 diabetic patients (4 women and 24 men, mean age 66.1±9.1 years) with urinary albumin excretion >300 mg/24 h and an estimated GFR <60 ml/min were included into this prospective double blind trial to receive either rosiglitazone (RSG) 4 mg b.i.d or matching placebo (PLC) for 52 weeks in addition to their concomitant antidiabetic background therapy. At baseline and after 26 and 52 weeks, renal plasma flow (RPF) and GFR were determined before and after blockade of nitric oxide (NO) by intravenous administration of N-monomethyl-L-arginine acetate. RSG treatment resulted in a significant reduction of proteinuria (2.4±1.1; 1.2±0.6; 1.5±0.7 g/d at baseline, 26 weeks and 52 weeks; respectively, p<0.05) whereas PLC did not influence proteinuria (1.6±0.6; 1.6±0.8; 1.7±0.8 g/d). GFR and RPF did not change significantly during the study, however, RSG improved the intrarenal NO bioavailability. RSG treatment was generally well tolerated and the major adverse event - development of edema - could be controlled by dose adjustment of the study drug and diuretic agents. In conclusion, we demonstrated a possible renoprotective effect of RSG in patients with advanced diabetic nephropathy.

[Hyponatremia]

Hyponatremia is the most common electrolyte disorder in the hospital setting and is defined as a serum sodium concentration less than 135 mmol/l. Most patients have mild hyponatremia (plasma sodium concentration 130-134 mmol/l) and few if any symptoms. Serum sodium concentrations between 120 and 129 mmol/l can be associated with lack of concentration, nausea, forgetfulness, apathy and loss of balance. Severe hyponatremia (<120 mmol/l) can cause coma or grand mal seizure. If hyponatremia occurs acutely (duration <48 h) it will cause more severe symptoms than are observed in chronic hyponatremia (>48 h). It is important to distinguish between different types of hyponatremia: euvolemic hyponatremia causing syndrome of inappropriate antidiuretic hormone secretion(SIADH) also known as Schwartz-Bartter syndrome, hypervolemic hyponatremia (cardiac failure and liver cirrhosis) and hypovolemic hyponatremia (diarrhoea, vomiting or other gastrointestinal fluid losses). Increased levels of ADH and continued fluid intake are the pathogenetic causes of all three types of hyponatremia; nonetheless, infusion of isotonic fluid is the therapy of choice for hypovolemic hyponatremia. In contrast, fluid restriction, lithium carbonate, urea, loop diuretics or demeclocycline have been used as therapeutic options to correct hyponatremia in euvolemic or hypervolemic hyponatremia but most of these therapies have proven to be cumbersome and inefficient. Recently a new class of pharmacological agents has become available, the vaptans, orally taken vasopressin antagonists. Clinical trials showed them to provide effective, specific and safe therapy of hyponatremia. In Europe tolvaptan, the only such agent on the market is now approved for the treatment of euvolemic hyponatremia.

Interplay between crystal field splitting and Kondo effect in CeNi9Ge(4-x)Si(x)

The pseudo-ternary solid solution CeNi(9)Ge(4-x)Si(x) (0 ≤ x ≤ 4) has been investigated by means of x-ray diffraction, magnetic susceptibility, specific heat, electrical resistivity, thermopower and inelastic neutron scattering studies. The isoelectronic substitution of germanium by silicon atoms causes a dramatic change of the relative strength of competing Kondo, RKKY and crystal field (CF) energy scales. The strongest effect is the continuous elevation of the Kondo temperature T(K) from approximately 3.5 K for CeNi(9)Ge(4) to about 70 K for CeNi(9)Si(4). This increase of the Kondo temperature is attended by a change of the CF level scheme of the Ce ions. The interplay of the different energy scales results in an incipient reduction of the ground state degeneracy from an effectively fourfold degenerate non-magnetic Kondo ground state with unusual non-Fermi-liquid features of CeNi(9)Ge(4) to a lower one, followed by an increase towards a sixfold, fully degenerate ground state multiplet in CeNi(9)Si(4) (T(K) ∼ Δ(CF)).

Beam position stabilization for a confocal multiphoton microscope

The influence of beam-pointing on scanning confocal microscopy is investigated. The beam displacement is measured using a quadrant photodiode, and the apparent movement of a sub-micron-sized particle observed by second-harmonic microscopy is linked to the beam displacement. A simple beam-pointing stabilization is implemented, and improvement of beam stability by three orders of magnitude on long time scales is achieved.

In situ visualization of damaged DNA in human sperm by Raman microspectroscopy

BACKGROUND

Beyond determining the percentage of damaged sperm, current methods of DNA assessment are of limited clinical utility as they render the sample unusable. We evaluated Raman microspectroscopy, a laser-based non-invasive technique that provides detailed chemical 'fingerprints' of cells and which potentially could be used for nuclear DNA-based sperm selection.

METHODS

Eight healthy donors provided ejaculates. After system optimization, a minimum of 200 air-dried sperm/sample/donor, prior to/and after UVB irradiation, were assessed by two observers. Spectra were analysed by Principal Component, Spectral Angle and Wavelet Analyses.

RESULTS

Spectra provided a chemical map delineating each sperm head region. Principal Component Analysis showed clear separation between spectra from UV-irradiated and untreated samples whilst averaged data identified two regions of interest (1040 and 1400 cm(-1)). Local spectral analysis around the DNA PO(4) backbone peak (1042 cm(-1)), showed that changes in this region were indicative of DNA damage. Wavelet decomposition confirmed both the 1042 cm(-1) shift and a second UVB susceptible region (1400-1600 cm(-1)) corresponding to protein-DNA interactions. No difference was found between observer measurements.

CONCLUSIONS

Raman microspectroscopy can provide accurate and reproducible assessment of sperm DNA structure and the sites and location of damage.

Frequency control of a 1163 nm singly resonant OPO based on MgO:PPLN

We report the realization of a singly resonant optical parametric oscillator (SRO) that is designed to provide narrow-bandwidth, continuously tunable radiation at a wavelength of 1163 nm for optical cooling of osmium ions. The SRO is based on periodically poled, magnesium-oxide-doped lithium niobate and pumped at 532 nm. The output coupling of the resonant idler wave is adjusted to yield up to 400 mW of 1163 nm radiation, with a bandwidth of a few megahertz. For continuous frequency tuning of the idler wave, the SRO is equipped with an intracavity etalon, and the cavity length is controlled with a piezo-actuated mirror synchronized to the etalon angle.

Fatty acids as metabolic mediators in innate immunity

BACKGROUND

Increasing data support the hypothesis of a local and systemic crosstalk between adipocytes and monocytes mediated by fatty acids. The aim of this study was to characterize the immunomodulatory effects of a large panel of fatty acids on cytokines and chemokines in monocytic THP-1 cells and primary human monocytes. We tested whether anti-inflammatory fatty acids are able to inhibit the binding of lipopolysaccharide (LPS) to its receptor, toll-like receptor/MD-2 (TLR4/MD-2).

MATERIALS AND METHODS

Resistin, monocyte chemoattractant protein-1 (MCP-1) and tumour necrosis factor (TNF) were measured by enzyme-linked immunosorbent assay. Proteins were analysed by Western blot. A designed Flag-tagged TLR4/MD-2 fusion protein (LPS trap) was used to investigate the effect of fatty acids on binding of LPS to its receptor. In 30 patients with type 2 diabetes mellitus (T2D), the correlation of serum triglyceride levels with LPS-induced monocyte activation was analysed.

RESULTS

Eleven fatty acids investigated exerted differential effects on the monocytic release of cytokines and chemokines. Eicosapentaenoic acid had potent anti-inflammatory effects on human primary monocytes and THP-1 cells; 100 and 200 microM eicosapentaenoic acid dose-dependently inhibited LPS binding to the LPS trap. LPS-induced release of monocytic MCP-1 and TNF was significantly and positively correlated with serum triglyceride levels in 30 patients with T2D.

CONCLUSIONS

Monocytic activation is differentially regulated by fatty acids and depends on triglyceride levels in T2D. The main finding of the present study shows that eicosapentaenoic acid inhibits the specific binding of LPS to TLR4/MD-2. Eicosapentaenoic acid represents a new anti-inflammatory LPS-antagonist.

Combined MRI and MRS in prostate cancer: improvement of spectral quality by susceptibility matching

PURPOSE

Local magnetic field inhomogeneity caused by susceptibility artifacts due to air in the endorectal coil substantially degrades the quality of 3D MR spectroscopic imaging (3D-MRSI). Perflubron (PFB) has magnetic susceptibility similar to that of human tissue. We prospectively assessed the effect of susceptibility matching using PFB on in vivo prostate (1)H-3D-MRSI.

MATERIALS AND METHODS

Ninety-one consecutive patients referred for 3D-MRSI were examined using air and PFB as the filling agent for endorectal coils at 1.5T with an identically placed PRESS box and sat bands. Solely auto-shim without additional manual shimming was used. The full width at half maximum (FWHM) of the water peak was statistically compared with a paired t-test. The spectral quality was visually evaluated for the definition of metabolite peaks and for the citrate peak split (duplet). The MR image quality was rated on a five-point scale.

RESULTS

FWHM was significantly less (p < 0.001) using PFB (mean 9.0 +/- 3.3, range 3 - 20) than air (mean 14.9 +/- 4.2, range 6 - 26) in 85/91 patients (93%). The spectral quality markedly improved using PFB and frequently the duplet of the citrate peak was able to be identified. Image quality ratings were similar (mean rating PFB 4.2, air 4.3 points). Omitting manual shimming led to a time savings of 4 min. per study.

CONCLUSION

3D-MRSI using PFB for susceptibility matching benefits from significantly better local field homogeneity, thus providing improved spectra quality. Combined with a substantial time savings in data acquisition, this may increase the clinical utilization of 3D-MRSI in patients with prostate cancer.

Application of spectral phase shaping to high resolution CARS spectroscopy

By spectral phase shaping of both the pump and probe pulses in coherent anti-Stokes Raman scattering (CARS) spectroscopy we demonstrate the extraction of the frequencies, bandwidths and relative cross sections of vibrational lines. We employ a tunable broadband Ti:Sapphire laser synchronized to a ps-Nd:YVO mode locked laser. A high resolution spectral phase shaper allows for spectroscopy with a precision better than 1 cm(-1) in the high frequency region around 3000 cm(-1). We also demonstrate how new spectral phase shaping strategies can amplify the resonant features of isolated vibrations to such an extent that spectroscopy and microscopy can be done at high resolution, on the integrated spectral response without the need for a spectrograph.

High-efficiency mid-infrared ZnGeP2 optical parametric oscillator directly pumped by a lamp-pumped, Q-switched CrTmHo:YAG laser

We report a singly resonant optical parametric oscillator (SRO) based on a ZnGeP(2) crystal directly pumped by a lamp-pumped Q-switched CrTmHo:YAG laser. The IR was tunable from 4.7 to 7.8 microm via crystal angle tuning. A maximum optical to optical efficiency of 56% was obtained from the pump (2.09 microm) to total IR at a pump energy of 6.5 mJ. The corresponding idler energy was 1.45 mJ. The SRO was measured to have a slope efficiency of 64% and a threshold of 1 mJ. The spatial beam quality of the idler, characterized by the M(2) parameter, was 1.38 when the SRO was pumped at 2.5 times threshold. These results show that ZnGeP(2) optical parametric oscillators directly pumped by a CrTmHo:YAG laser can be operated efficiently, while maintaining good IR beam quality.

A precise method to determine the angular distribution of backscattered light to high angles

We present an approach to measure the angular dependence of the diffusely scattered intensity of a multiple scattering sample in backscattering geometry. Increasing scattering strength give rise to an increased width of the coherent backscattering and sets higher demands on the angular detection range. This is of particular interest in the search for the transition to Anderson localization of light. To cover a range of -60 degrees to +85 degrees from direct back-reflection, we introduced a new parallel intensity recording technique. This allows one-shot measurements, with fast alignment and short measuring time, which prevents the influence of illumination variations. Configurational average is achieved by rotating the sample and singly scattered light is suppressed with the use of circularly polarized light up to 97%. This implies that backscattering enhancements of almost two can be achieved. In combination with a standard setup for measuring small angles up to +/-3 degrees , a full characterization of the coherent backscattering cone can be achieved. With this setup we are able to accurately determine transport mean free paths as low as 235 nm.