Bending Magnet Synchrotron Radiation Imaging with Large Orbital Collection Angles

Synchrotron radiation (SR) from bending magnets, wigglers, and undulators is now extensively produced for users at storage ring based light sources, with unique properties in terms of average brightness and stability. We present a profound study of bending magnet SR intensity distribution in the image plane of a focusing optical system. Measurements of this intensity distribution at the MAX-IV low emittance storage ring are compared to theoretical predictions, and found to be in excellent agreement. This work shows upon the possibility of performing high resolution emittance diagnostics with visible or near-visible SR on upcoming low-emittance storage ring based light sources. As a byproduct of our study, we derive a closed analytical expression for the intensity distribution from a zero-emittance beam, in the limiting case of wide orbital collection angles. This expression finally allows us to demonstrate the meeting between classical electrodynamics applied to SR emission and focusing, and the Landau and Lifshitz prediction of radiation intensity distribution nearby a caustic.

Abstract 97: Association Between Use Of A Flying Intervention Team Versus Patient Interhospital Transfer And Longterm Clinical Outcome Among Patients With Acute Ischemic Stroke And Large Vessel Occlusion In Non-urban Germany

Background and Aims: Use of a Flying Intervention Team has shown to significantly reduce time to endovascular thrombectomy compared to interhospital transfer. Aim of this study is to determine whether this new system of care is also associated with improved long-term outcome.

Methods: This is a non-randomized controlled intervention study comparing two systems of care in alternating weeks. Thirteen telemedicine assisted primary stroke centers in a non-urban region in Germany participated. Acute ischemic stroke patients for whom the decision to pursue thrombectomy had been made, were either treated by a Flying Intervention Team (an interventionist and a nurse flown by a dedicated helicopter to the primary stroke center to perform thrombectomy on site), or were transferred to the closest referral center. Enrollment was between 2018-02-01 and 2019-10-24. In this secondary analysis, results of the modified Rankin Scale (mRS), Barthel Index, and mortality rate after 12 months were compared between groups.

Results: Among 146 patients included, 70 received flying team care and 76 were transferred. Functional outcome (ordinal mRS) after 12 months was significantly improved in the FIT group (acOR, 1.96; 95% CI [1.05-3.69]; p = 0.036). No significant differences were found for Barthel Index in surviving patients and mortality rate.

Conclusion: Deployment of a Flying Intervention Team was associated with significantly improved functional outcome at 12 months. FIT should be considered as a system of care for primary stroke centers with adequate infrastructure and sufficient experience in stroke management onsite.

Cryptic diversity impacts model selection and macroevolutionary inferences in diversification analyses

Species persist in landscapes through ecological dynamics but proliferate at wider spatial scales through evolutionary mechanisms. Disentangling the contribution of each dynamic is challenging, but the increasing use of dated molecular phylogenies opened new perspectives. First, the increasing use of DNA sequences in biodiversity inventory shed light on a substantial amount of cryptic diversity in species-rich ecosystems. Second, explicit diversification models accounting for various eco-evolutionary models are now available. Integrating both advances, we explored diversification trajectories among 10 lineages of freshwater fishes in Sundaland, for which time-calibrated and taxonomically rich phylogenies are available. By fitting diversification models to dated phylogenies and incorporating DNA-based species delimitation methods, the impact of cryptic diversity on diversification model selection and related inferences is explored. Eight clades display constant speciation rate model as the most likely if cryptic diversity is accounted, but nine display a signature of diversification slowdowns when cryptic diversity is ignored. Cryptic diversification occurs during the last 5 Myr for most groups, and palaeoecological models received little support. Most cryptic lineages display restricted range distribution, supporting geographical isolation across homogeneous landscapes as the main driver of diversification. These patterns question the persistence of cryptic diversity and its role during species proliferation.

Identification of Stroke and TIA in Patients With Acute Dizziness, Vertigo or Imbalance in Emergency Departments of Primary Care Hospitals: Early Experiences With a Network-Based Telemedical Approach

Background

Acute dizziness, vertigo, and imbalance are frequent and difficult to interpret symptoms in the emergency department (ED). Primary care hospitals often lack the expertise to identify stroke or TIA as underlying causes. A telemedical approach based on telestroke networks may offer adequate diagnostics and treatment.

Aim

The aim of this study is to evaluate the accuracy of a novel ED algorithm in differentiating between peripheral and central vestibular causes.

Methods

Within the Telemedical Project for Integrative Stroke Care (TEMPiS), a telemedical application including a videooculography (VOG) system was introduced in 2018 in 19 primary care spoke hospitals. An ED triage algorithm was established for all patients with acute dizziness, vertigo, or imbalance of unknown cause (ADVIUC) as a leading complaint. In three predefined months, all ADVIUC cases were prospectively registered and discharge letters analyzed. Accuracy of the ED triage algorithm in differentiation between central and peripheral vestibular cases was analyzed by comparison of ED diagnoses to final discharge diagnoses. The rate of missed strokes was calculated in relation to all cases with a suitable brain imaging. Acceptance of teleconsultants and physicians in spoke hospitals was assessed by surveys.

Results

A total number of 388 ADVIUC cases were collected, with a median of 12 cases per months and hospital (IQR 8–14.5). The most frequent hospital discharge diagnoses are vestibular neuritis (22%), stroke/TIA (18%), benign paroxysmal positioning vertigo (18%), and dizziness due to internal medicine causes (15%). Detection of a central vestibular cause by the ED triage algorithm has a high sensitivity (98.6%), albeit poor specificity (45.9%). One stroke out of 32 verified by brain scan was missed (3.1%). User satisfaction, helpfulness of the project, improvement of care, personal competence, and satisfaction about handling of the VOG systems were rated consistently positive.

Discussion

The concept shows good acceptance for a telemedical and network-based approach to manage ADVIUC cases in the ED of primary care hospitals. Identification of stroke cases is accurate, while specificity needs further improvement. The concept could be a major step toward a broadly available state of the art diagnostics and therapy for patients with ADVIUC in primary care hospitals.

Feasibility of Telemedical HINTS (Head Impulse-Nystagmus-Test of Skew) Evaluation in Patients With Acute Dizziness or Vertigo in the Emergency Department of Primary Care Hospitals

Background

Acute dizziness, vertigo and imbalance are common symptoms in emergency departments. Stroke needs to be distinguished from vestibular diseases. A battery of three clinical bedside tests (HINTS: Head Impulse Test, Nystagmus, Test of Skew) has been shown to detect stroke as underlying cause with high reliability, but implementation is challenging in primary care hospitals. Aim of this study is to prove the feasibility of a telemedical HINTS examination via a remotely controlled videooculography (VOG) system.

Methods

The existing video system of our telestroke network TEMPiS (Telemedic Project for Integrative Stroke Care) was expanded through a VOG system. This feature enables the remote teleneurologist to assess a telemedical HINTS examination based on inspection of eye movements and quantitative video head impulse test (vHIT) evaluation. ED doctors in 11 spoke hospitals were trained in performing vHIT, nystagmus detection and alternating cover test. Patients with first time acute dizziness, vertigo or imbalance, whether ongoing or resolved, presented to the teleneurologist were included in the analysis, as long as no focal neurological deficit according to the standard teleneurological examination or obvious internal medicine cause was present and a fully trained team was available. Primary outcome was defined as the feasibility of the telemedical HINTS examination.

Results

From 01.06.2019 to 31.03.2020, 81 consecutive patients were included. In 72 (88.9%) cases the telemedical HINTS examination was performed. The complete telemedical HINTS examination was feasible in 46 cases (63.9%), nystagmus detection in all cases (100%) and alternating covert test in 70 cases (97.2%). The vHIT was recorded and interpretable in 47 cases (65.3%). Results of the examination with the VOG system yielded clear results in 21 cases (45.7%) with 14 central and 7 peripheral lesions. The main reason for incomplete examination was the insufficient generation of head impulses.

Conclusion

In our analysis the telemedical HINTS examination within a telestroke network was feasible in two thirds of the patients. This offers the opportunity to improve specific diagnostics and therapy for patients with acute dizziness and vertigo even in primary care hospitals. Improved training for spoke hospital staff is needed to further increase the feasibility of vHIT.

Abstract TP158: High Mortality In In-Hospital-Stroke Patients After Interhospital Transfer For Endovascular Therapy

There are only few studies examining In-Hospital-Stroke- (IHS) patients with a large vessel occlusion and subsequent transfer to a comprehensive stroke center for endovascular therapy (EVT). However, this patient group is highly relevant given the substantial amount of IHS, the ongoing trend towards a more frequent use of EVT and the lack of EVT capacities in rural hospitals. Furthermore, these patients are particularly vulnerable, as IHS is associated with higher rates of pre-existing conditions and worse clinical outcomes. We retrospectively analyzed prospectively collected data of patients receiving EVT after interhospital transfer from 15 rural hospitals of the Telemedical Stroke Network in Southeast Bavaria, Germany ( TEMPiS ) between 02-2018 and 07-2020. Baseline characteristics, treatment times and outcomes were compared between IHS- and Out-of-Hospital-Stroke- (OHS) patients. Primary endpoint was mRS after 3 months. A total of 49 IHS-patients and 274 OHS-patients received EVT after interhospital transfer. IHS-patients had a higher prevalence of atrial fibrillation (55.3% vs. 35.9%, p= 0.012), diabetes (36.2% vs. 21.1%, p= 0.024) and use of oral anticoagulants (44.7% vs. 20.8%, p< 0.001). Severity of stroke was similar in both groups. Treatment times from symptom onset to first brain imaging, therapy decision or groin puncture were significantly shorter for IHS-patients. IHS-patients displayed significantly worse outcomes: 59.2% of them died within 3 months compared to only 28.5% of OHS-patients (p< 0.001). Additionally, they were less likely to achieve moderate outcomes (mRS 0-3) 3 months after stroke (20.4% vs. 39.8%, p= 0.010). A logistic regression analysis revealed that - after controlling for possible confounding variables such as severity of stroke, premorbid state, pre-existing conditions, age and gender - IHS was significantly associated with a higher chance of death (adjusted OR: 3.99 (95%-CI: 1.84-8.92), p< 0.001). The mortality rate of IHS-patients who underwent EVT after interhospital transfer was substantially higher than that of OHS-patients. Thus, this patient group may not benefit from this therapeutic approach. In future studies alternative approaches that circumvent interhospital transfer should be explored.

Achieving reduced radiation doses for CT examination of the brain using optimal exposure parameters

Objectives : Examinations performed using CT scanners impart high radiation dose to patients and use of this modality is on the increase in the present day scenario. This study was intended to evaluate and optimize radiation dose imparted to patients during CT examination of brain performed using spiral CT scanner. Materials and Methods : One hundred and one patients who underwent CT examination of brain were included in the study. The effective dose to patients was calculated using volume computed tomography dose index (CTDIvol) and dose length product (DLP) values. Patients were categorized according to the type of examination involved. Patients who underwent a complete examination of brain (non-contrast as well as contrast) were categorized in Group A and patients who underwent either a non-contrast or contrast examination were categorized as Group B. Results : The effective dose to patients ranged from 0.65 mSv to 0.93 mSv for Group A patients and 0.28 mSv to 0.53 mSv for Group B patients. Conclusion : There was a reduction of doses imparted to patients undergoing CT examination of the brain using optimized exposure parameters without any loss of diagnostic information.

Impact of the coronavirus disease 2019 pandemic on stroke teleconsultations in Germany in the first half of 2020

Background and purpose

The effects of the coronavirus disease 2019 (COVID‐19) pandemic on telemedical care have not been described on a national level. Thus, we investigated the medical stroke treatment situation before, during, and after the first lockdown in Germany.

Methods

In this nationwide, multicenter study, data from 14 telemedical networks including 31 network centers and 155 spoke hospitals covering large parts of Germany were analyzed regarding patients' characteristics, stroke type/severity, and acute stroke treatment. A survey focusing on potential shortcomings of in‐hospital and (telemedical) stroke care during the pandemic was conducted.

Results

Between January 2018 and June 2020, 67,033 telemedical consultations and 38,895 telemedical stroke consultations were conducted. A significant decline of telemedical (p < 0.001) and telemedical stroke consultations (p < 0.001) during the lockdown in March/April 2020 and a reciprocal increase after relaxation of COVID‐19 measures in May/June 2020 were observed. Compared to 2018–2019, neither stroke patients' age (p = 0.38), gender (p = 0.44), nor severity of ischemic stroke (p = 0.32) differed in March/April 2020. Whereas the proportion of ischemic stroke patients for whom endovascular treatment (14.3% vs. 14.6%; p = 0.85) was recommended remained stable, there was a nonsignificant trend toward a lower proportion of recommendation of intravenous thrombolysis during the lockdown (19.0% vs. 22.1%; p = 0.052). Despite the majority of participating network centers treating patients with COVID‐19, there were no relevant shortcomings reported regarding in‐hospital stroke treatment or telemedical stroke care.

Conclusions

Telemedical stroke care in Germany was able to provide full service despite the COVID‐19 pandemic, but telemedical consultations declined abruptly during the lockdown period and normalized after relaxation of COVID‐19 measures in Germany.

Establishment of an internationally agreed minimum data set for acute telestroke

INTRODUCTION

Globally, the use of telestroke programmes for acute care is expanding. Currently, a standardised set of variables for enabling reliable international comparisons of telestroke programmes does not exist. The aim of the study was to establish a consensus-based, minimum dataset for acute telestroke to enable the reliable comparison of programmes, clinical management and patient outcomes.

METHODS

An initial scoping review of variables was conducted, supplemented by reaching out to colleagues leading some of these programmes in different countries. An international expert panel of clinicians, researchers and managers (n = 20) from the Australasia Pacific region, USA, UK and Europe was convened. A modified-Delphi technique was used to achieve consensus via online questionnaires, teleconferences and email.

RESULTS

Overall, 533 variables were initially identified and harmonised into 159 variables for the expert panel to review. The final dataset included 110 variables covering three themes (service configuration, consultations, patient information) and 12 categories: (1) details about telestroke network/programme (n = 12), (2) details about initiating hospital (n = 10), (3) telestroke consultation (n = 17), (4) patient characteristics (n = 7), (5) presentation to hospital (n = 5), (6) general clinical care within first 24 hours (n = 10), (7) thrombolysis treatment (n = 10), (8) endovascular treatment (n = 13), (9) neurosurgery treatment (n = 8), (10) processes of care beyond 24 hours (n = 7), (11) discharge information (n = 5), (12) post-discharge and follow-up data (n = 6).

DISCUSSION

The acute telestroke minimum dataset provides a recommended set of variables to systematically evaluate acute telestroke programmes in different countries. Adoption is recommended for new and existing services.

Tunable High Spatio-Spectral Purity Undulator Radiation from a Transported Laser Plasma Accelerated Electron Beam

Undulator based synchrotron light sources and Free Electron Lasers (FELs) are valuable modern probes of matter with high temporal and spatial resolution. Laser Plasma Accelerators (LPAs), delivering GeV electron beams in few centimeters, are good candidates for future compact light sources. However the barriers set by the large energy spread, divergence and shot-to-shot fluctuations require a specific transport line, to shape the electron beam phase space for achieving ultrashort undulator synchrotron radiation suitable for users and even for achieving FEL amplification. Proof-of-principle LPA based undulator emission, with strong electron focusing or transport, does not yet exhibit the full specific radiation properties. We report on the generation of undulator radiation with an LPA beam based manipulation in a dedicated transport line with versatile properties. After evidencing the specific spatio-spectral signature, we tune the resonant wavelength within 200-300 nm by modification of the electron beam energy and the undulator field. We achieve a wavelength stability of 2.6%. We demonstrate that we can control the spatio-spectral purity and spectral brightness by reducing the energy range inside the chicane. We have also observed the second harmonic emission of the undulator.

Data on changes to mucosal inflammation and the intestinal microbiota following dietary micronutrients in genetically susceptible hosts

These data support the findings that dietary micronutrients influence the inflammatory responses and intestinal microbial community structure and function in a model of pouchitis-like small bowel inflammation reported in “Dietary Antioxidant Micronutrients Alter Mucosal Inflammatory Risk in a Murine Model of Genetic and Microbial Susceptibility” (Pierre et al., 2018) [1]. Briefly, wild-type and IL-10 deficient mice underwent surgical placement of small intestinal self-filling loops (SFL) and were subsequently fed purified control diet (CONT) or control diet supplemented with 4 micronutrients (AOX), retinoic acid, Vitamin C, Vitamin E, and selenium, for 14 days. These data include changes in host markers, such as body weight, mucosal levels of myeloperoxidase and syndecan-1, and luminal IgA and IgG levels. These data also include changes in the microbial compartment, including 16S community structure in the self-filling loop, conventionalized germ-free mice, and microbial substrate preference performed through anaerobic bacterial culturing of SLF CONT and AOX microbiota.

Endocrine disorders in Woodhouse-Sakati syndrome: a systematic review of the literature

First described in 1983, Woodhouse-Sakati syndrome (WSS) is a rare autosomal recessive genetic disorder that leads to a spectrum of hypogonadal symptoms in adolescence. The responsible gene, DCAF17 located on chromosome 2q31.1, was discovered in 2008 and to date nine mutations have been reported in the literature. The aim of the study was to review WSS descriptively in the light of new case reports with focus on endocrine features. Phenotypic description of three patients (two females, one male) with WSS followed in the Endocrinology Department of the University Hospital of Nancy, France, and exhaustive review of the literature using the PUBMED database were performed. Of 72 patients from 29 families with documented WSS who were identified, 39 had undergone genetic testing. WSS was invariably associated with hypogonadism, decreased IGF1 and frontotemporal alopecia starting in childhood. In addition to this triad, some patients exhibited intellectual disabilities of varying severity (87 %), bilateral deafness (76 %), cervicofacial dystonia and limb pain (42 % of cases, rising to 89 % after 25 years) and diabetes (66 %, rising to 96 % after 25 years). The pathophysiology of WSS remains unclear.

Factors affecting the Haemophilia Joint Health Score in children with severe haemophilia

Joint damage from bleeding episodes leads to physical or functional limitations in people with haemophilia. Various factors may influence the frequency and severity of joint damage. This study examined whether age, prophylaxis, history of high-titre inhibitors (HTI) and bleeding events influenced the Haemophilia Joint Health Score (HJHS) in children. Medical and physiotherapy notes of boys with severe haemophilia, aged 4-18 years, were reviewed to identify factors associated with increased HJHS. The HJHS of 83 boys (median age: 11) ranged from 0 to 25, with 44/83 (53%) having a score of zero. The median HJHS was 0 (mean 2.6). In the non-HTI group, the HJHS for boys on late prophylaxis was 2.68 times higher than those who started early and the HJHS was on average 10% higher for every additional recent bleed. In this group the odds of having a zero score fell by 30% for every year increase in age. Boys with a history of HTI had higher HJHS scores than the non-HTI group, and age, number of recent bleeds and tolerized status were positively associated with HJHS. The score rose on average by 28% for every year of age and by 76% for non-tolerized boys. This study provides further evidence supporting early prophylaxis use and the importance of immune tolerance therapy. The HJHS is a useful tool for identifying and tracking changes in joint health with respect to therapy or disease progression. With improvements in haemophilia treatment, the disproportionate number of zero scores will continue to make interpretation of the HJHS challenging.

Ergonomic assessment of the surgeon's physical workload during standard and robotic assisted laparoscopic procedures

BACKGROUND

Standard laparoscopy is responsible for musculoskeletal problems because of surgeons anti-ergonomic positions. Robot-assisted laparoscopy seems to reduce these musculoskeletal disorders thanks to the surgeons seated position. The objective of this study is to evaluate the muscular strain and cognitive stress induced by these two techniques during real operations conducted on the pig.

METHODS

Electromyographic activities, heart rate, physical and mental workloads (NASA Tlx and Borg CR-10) were recorded.

RESULTS

Physical workload and perception of the effort invested was significantly greater during the standard laparoscopies (p<0.05). Mental stress was however identical for the two techniques. In Standard Laparoscopic group, greater physical activity was found for trapezius and dorso-lumbar muscles, and significant appearance of fatigue of the trapezius muscles should also be noted. Finally, heart rate during standard laparoscopy was increased (92.1 ± 1.6 bpm vs 83.7 ± 1.8, p<0,01), confirming greater physical expenditure.

CONCLUSIONS

Robot-assisted laparoscopy is a less physically stressful surgical technique than standard laparoscopy.

[Dermohypodermitis and gut translocation Escherichia coli septicemia in a newborn infant]

The burden of neonatal bacterial infections continues. They remain a significant cause of death and morbidity, despite recommendations for prevention. The epidemiology of these infections has changed. Currently the two most causative pathogens for early-onset neonatal sepsis and for late-onset sepsis in term infants are Group B streptococci (GBS) and Escherichia coli. E. coli's role is increasingly important since the widespread use of intrapartum antibiotic prophylaxis. In late-onset infections, one of the suggested pathophysiological mechanisms is microbial translocation in the gut secondary to digestive colonization, particularly when E. coli is isolated in blood cultures. This can occur either before or after birth. Bacterial sepsis can be associated with various non-specific peripheral manifestations involving skin and soft tissues. We report the case of a full-term, 26-day-old newborn admitted to the hospital for fever. She presented with dermohypodermitis of the left trunk and was diagnosed with E. coli septicemia. She was discharged in good condition after appropriate intravenous antibiotic therapy.

Assessing noise sources at synchrotron infrared ports

Today, the vast majority of electron storage rings delivering synchrotron radiation for general user operation offer a dedicated infrared port. There is growing interest expressed by various scientific communities to exploit the mid-IR emission in microspectroscopy, as well as the far infrared (also called THz) range for spectroscopy. Compared with a thermal (laboratory-based source), IR synchrotron radiation sources offer enhanced brilliance of about two to three orders of magnitude in the mid-IR energy range, and enhanced flux and brilliance in the far-IR energy range. Synchrotron radiation also has a unique combination of a broad wavelength band together with a well defined time structure. Thermal sources (globar, mercury filament) have excellent stability. Because the sampling rate of a typical IR Fourier-transform spectroscopy experiment is in the kHz range (depending on the bandwidth of the detector), instabilities of various origins present in synchrotron radiation sources play a crucial role. Noise recordings at two different IR ports located at the Swiss Light Source and SOLEIL (France), under conditions relevant to real experiments, are discussed. The lowest electron beam fluctuations detectable in IR spectra have been quantified and are shown to be much smaller than what is routinely recorded by beam-position monitors.

Morphology-diet relationships in four killifishes (Teleostei, Cyprinodontidae, Orestias) from Lake Titicaca

This study explores the relationship between morphology and diet in four Andean killifishes (Orestias) from Lake Titicaca that are known to differ in habitat use. Species that fed preferentially on amphipods (Orestias albus) or molluscs (Orestias luteus) separated in multivariate space from other species that feed on cladocera and algae (Orestias agassii and Orestias jussiei). Generally, specimens feeding on cladocera were characterized by a short, blunt nose with a small mouth; whereas, specimens feeding on amphipods exhibited a long snout with a large mouth. Specimens including molluscs in their diet tended to have a larger posterior part of the head and the larger opercles than others; while the occurrence of substratum in gut content was generally related to a short but deep head. The present analysis suggests that the littoral O. jussiei has an intermediate phenotype and diet between the pelagic (O. agassii) and benthic (O. albus and O. luteus) species. Results suggest that resource partitioning was occurring and that several morphological traits relate to characteristics of the diet, and it is inferred that the benthic, the pelagic and the littoral zones in the lake host different prey communities constituting distinct adaptive landscapes.

[Surgical and forensic problems of body-packing]

Body-packing has increased as a means of illicit drug transportation, particularly since the intensification of customs control and luggage inspection which followed the terrorist attacks of September 11, 2001. This mode of drug transport may result in intestinal obstruction or systemic intoxication; diagnostic measures are discussed; management may require specific precautions and occasionally surgical intervention. The problem of how to handle and dispose of large quantities of drugs removed from or passed by a patient who may not be under arrest presents specific medicolegal considerations.

[The obligation of means and the obligation of results]

Several important decisions were made in 2000 concerning the proof of malpractice and the fundamental principles of medical responsibility. In order to guarantee indemnities for victims of medical accidents, the French courts have facilitated the implication of medical responsibility for medical accidents. The notion of a "virtual fault" was developed allowing the courts to retain the responsibility of the surgeon for instance for injury to the sublingual nerve during extraction of a wisdom tooth or for injury to the popliteal artery (March 23, 2000). These decisions not only facilitate the demonstration of malpractice but also modify the definition of responsibility, all physicians being required to use all available means. Likewise, although jurisprudence asserts that a safe result is mandatory in certain areas, the essential obligation is the absence of "fault" and not the result despite the disquieting arguments put forward by the Paris appeals court in its January 15, 1999 decree. The patient's right to a result was sustained only in well defined areas.

Complete autoerotic asphyxiation: suicide or accident?

A case of a typical form of sexual asphyxiation is described, involving a young man hanging, in a context of autoerotic asphyxia. Multiple and different parameters are included in the definition.

[Rare association of hypoparathyroidism and mediastinal-pulmonary sarcoidosis]

We report the case of a 52-year-old woman who presented hypoparathyroidism and sarcoidosis. The hypoparathyroidism developed 8 years after the diagnosis of sarcoidosis. No element in favor of an autoimmune disease of the parathyroid could be evidenced. Pathology and immunology blood tests were equally noncontributive. Another pathophysiological mechanism, possibly sarcoidic granulomatous infiltration of the parathyroid glands, was suspected. The patient also presented apparently coincidental vitiligo.

Characterization of mSelB, a novel mammalian elongation factor for selenoprotein translation

Decoding of UGA selenocysteine codons in eubacteria is mediated by the specialized elongation factor SelB, which conveys the charged tRNA(Sec) to the A site of the ribosome, through binding to the SECIS mRNA hairpin. In an attempt to isolate the eukaryotic homolog of SelB, a database search in this work identified a mouse expressed sequence tag containing the complete cDNA encoding a novel protein of 583 amino acids, which we called mSelB. Several lines of evidence enabled us to establish that mSelB is the bona fide mammalian elongation factor for selenoprotein translation: it binds GTP, recognizes the Sec-tRNA(Sec) in vitro and in vivo, and is required for efficient selenoprotein translation in vivo. In contrast to the eubacterial SelB, the recombinant mSelB alone is unable to bind specifically the eukaryotic SECIS RNA hairpin. However, complementation with HeLa cell extracts led to the formation of a SECIS-dependent complex containing mSelB and at least another factor. Therefore, the role carried out by a single elongation factor in eubacterial selenoprotein translation is devoted to two or more specialized proteins in eukaryotes.

Proteasomes regulate the duration of erythropoietin receptor activation by controlling down-regulation of cell surface receptors

The binding of erythropoietin (Epo) to its receptor leads to the transient phosphorylation of the Epo receptor (EpoR) and the activation of intracellular signaling pathways. Inactivation mechanisms are simultaneously turned on, and Epo-induced signaling pathways return to nearly basal levels after 30-60 min of stimulation. We show that proteasomes control these inactivation mechanisms. In cells treated with the proteasome inhibitors N-Ac-Leu-Leu-norleucinal (LLnL) or lactacystin, EpoR tyrosine phosphorylation and activation of intracellular signaling pathways (Jak2, STAT5, phosphatidylinositol 3-kinase) were sustained for at least 2 h. We show that this effect was due to the continuous replenishment of the cell surface pool of EpoRs in cells treated with proteasome inhibitors. Proteasome inhibitors did not modify the internalization and degradation of Epo.EpoR complexes, but they allowed the continuous replacement of the internalized receptors by newly synthesized receptors. Proteasome inhibitors did not modify the synthesis of EpoRs, but they allowed their transport to the cell surface. N-Ac-Leu-Leu-norleucinal, but not lactacystin, also inhibited the degradation of internalized Epo.EpoR complexes, most probably through cathepsin inhibition. The internalized EpoRs were not tyrosine-phosphorylated, and they did not activate intracellular signaling pathways. Our results show that the proteasome controls the down-regulation of EpoRs in Epo-stimulated cells by inhibiting the cell surface replacement of internalized EpoRs.

The selenocysteine insertion sequence binding protein SBP is different from the Y-box protein dbpB

In eukaryotes, translation of internal UGA selenocysteine codons requires the SECIS stem-loop structure in the 3'UTR of selenoprotein mRNAs. In an earlier work, we identified SBP as a selenocysteine insertion sequence (SECIS)-binding protein. Here, the yeast three-hybrid screen was employed to capture the cDNA of SBP. One candidate, satisfying the genetic screens, was identified as the already known dbpB protein. Although it was also found by another group, but with a different strategy, to carry SECIS-binding activity, further experiments enabled us to show that dbpB was unable to bind the SECIS element in vitro. Altogether, our findings led us to conclude that, under our conditions, dbpB and SBP are two distinct proteins.

Solution structure of SECIS, the mRNA element required for eukaryotic selenocysteine insertion--interaction studies with the SECIS-binding protein SBP

Selenocysteine, a selenium-containing analog of cysteine, is found in the prokaryotic and eukaryotic kingdoms in active sites of enzymes involved in oxidation-reduction reactions. This aminoacid is cotranslationally incorporated at UGA codons which usually act as translation stop codons. In eukaryotes, decoding of selenocysteine necessitates the participation of the selenocysteine insertion sequence (SECIS), an element lying in the 3'-untranslated region of selenoprotein mRNAs. A detailed experimental study of the secondary structures of the SECIS elements of rat and human type 1 iodothyronine deiodinases and rat glutathione peroxidase was performed. Enzymatic and chemical structure probing led us to propose a secondary structure model, supported by sequence comparison of 23 SECIS mRNAs. The secondary structure model revealed the existence of a novel type of RNA motif composed of four consecutive non-Watson-Crick base-pairs. Using gel shift experiments, we identified in several mammalian cell type extracts the protein SBP, for SECIS-binding protein, that specifically recognizes the iodothyronine deiodinases and glutathione peroxidase SECIS elements. The structural model that we derived for the SECIS RNAs discloses RNA features possibly implicated in the binding of SBP and/or SECIS function.

Iron may induce both DNA synthesis and repair in rat hepatocytes stimulated by EGF/pyruvate

BACKGROUND/AIMS

Hepatocellular carcinoma develops frequently in the course of genetic hemochromatosis, and a role of iron overload in hepatic carcinogenesis is strongly suggested.

METHODS

The aim of our study was to investigate the effect of iron exposure on DNA synthesis of adult rat hepatocytes maintained in primary culture stimulated or not by EGF/pyruvate and exposed to iron-citrate complex.

RESULTS

In EGF/pyruvate-stimulated cultures, the level of [3H] methyl thymidine incorporation was strongly increased as compared to unstimulated cultures. The addition of iron to stimulated cultures increased [3H] methyl thymidine incorporation. The mitotic index was also significantly higher at 72 h. However, the number of cells found in the cell layer was not significantly different from iron-citrate free culture. By flow cytometry, no difference in cell ploidy was found between iron-treated and untreated EGF/pyruvate-stimulated cultures. A significant increase in LDH leakage reflecting a toxic effect of iron was found in the cell medium 48 h after cell seeding. In addition, [3H] methyl thymidine incorporation in the presence of hydroxyurea was increased in iron-treated compared to untreated cultures.

CONCLUSIONS

Our results show that DNA synthesis is increased in the presence of iron in rat hepatocyte cultures stimulated by EGF/pyruvate, and they suggest that DNA synthesis is likely to be related both to cell proliferation and to DNA repair. These observations may allow better understanding of the role of iron overload in the development of hepatocellular carcinoma.

Molecular-mapping analysis in Brassica napus using isozyme, RAPD and RFLP markers on a doubled-haploid progeny

We have undertaken the construction of a Brassica napus genetic map with isozyme (4%), RFLP (26.5%) and RAPD (68%) markers on a 152 lines of a doubled-haploid population. The map covers 1765 cM and comprises 254 markers including three PCR-specific markers and a morphological marker. They are assembled into 19 linkage groups, covering approximatively 71% of the rapeseed genome. Thirty five percent of the studied markers did not segregate according to the expected Mendelian ratio and tended to cluster in eight specific linkage groups. In this paper, the structure of the genetic map is described and the existence of non-Mendelian segregations in linkage analysis as well as the origins of the observed distortions, are discussed. The mapped RFLP loci corresponded to the cDNAs already used to construct B. napus maps. The first results of intraspecific comparative mapping are presented.

A protein binds the selenocysteine insertion element in the 3'-UTR of mammalian selenoprotein mRNAs

Several gene products are involved in co-translational insertion of selenocysteine by the tRNA(Sec). In addition, a stem-loop structure in the mRNAs coding for selenoproteins is essential to mediate the selection of the proper selenocysteine UGA codon. Interestingly, in eukaryotic selenoprotein mRNAs, this stem-loop structure, the selenocysteine insertion sequence (SECIS) element, resides in the 3'-untranslated region, far downstream of the UGA codon. In view of unravelling the underlying complex mechanism, we have attempted to detect RNA-binding proteins with specificity for the SECIS element. Using mobility shift assays, we could show that a protein, present in different types of mammalian cell extracts, possesses the capacity of binding the SECIS element of the selenoprotein glutathione peroxidase (GPx) mRNA. We have termed this protein SBP, for Secis Binding Protein. Competition experiments attested that the binding is highly specific and UV cross-linking indicated that the protein has an apparent molecular weight in the range of 60-65 kDa. Finally, some data suggest that the SECIS elements in the mRNAs of GPx and another selenoprotein, type I iodothyronine 5' deiodinase, recognize the same SBP protein. This constitutes the first report of the existence of a 3' UTR binding protein possibly involved in the eukaryotic selenocysteine insertion mechanism.

RNAs mediating cotranslational insertion of selenocysteine in eukaryotic selenoproteins

Selenocysteine, a selenium-containing analog of cysteine, is found in the prokaryotic and eukaryotic kingdoms in active sites of enzymes involved in oxidation-reduction reactions. Its biosynthesis and cotranslational insertion into selenoproteins is performed by an outstanding mechanism, implying the participation of several gene products. The tRNA(Sec) is one of these. In eukaryotes, its transcription mode by RNA polymerase III differs from that of classical tRNA genes, both at the level of the promoter elements and transcription factors involved. In addition, enhanced transcription is afforded by a newly characterized zinc finger activator. Not only transcription of the gene, but also the tRNA(Sec) itself is atypical since its 2D and 3D structures exhibit features which set it apart from classical tRNAs. Decoding of eukaryotic selenocysteine UGA codons requires a stem-loop structure in the 3'UTR of mRNAs, the selenocysteine insertion sequence (SECIS) element. Structure probing and sequence comparisons led us to propose a 2D structure model for the SECIS element, containing a novel RNA motif composed of four consecutive non-Watson-Crick base-pairs. A 3D model, rationalizing the accessibility data, was elaborated by computer modeling. It yields indicative or suggestive evidence for the role that could play some conserved residues and/or structural features in SECIS function. These might act as signals for interaction with SBP, the SECIS binding protein that we have characterized.

Regulation of ferritin expression by alcohol in a human hepatoblastoma cell line and in rat hepatocyte cultures

Serum ferritin increases in chronic alcoholism, without clear explanation. We have previously shown that alcohol increases ferritin levels in a human hepatoblastoma cell line (HepG2). The aims of the present work were: 1) To extend our results in normal rat hepatocyte cultures, and 2) To determine the mechanism by which alcohol enhances ferritin levels. In HepG2 cells, high alcohol concentrations (300 mM) during long exposure (4 days) increased the synthesis of H and L ferritin subunits, in association with increased levels of ferritin mRNAs. In rat hepatocyte cultures, the synthesis of L ferritin increased after 24 h of exposure to lower alcohol concentrations (10 mM); alcohol had no effect on ferritin mRNAs levels. In both cell types, the alcohol effect was not related to an increase in iron intracellular incorporation. In HepG2 cells, desferrioxamine (Df), a potent iron chelator, abolished ferritin synthesis in the presence or absence of alcohol, and abolished the alcohol induction of ferritin mRNAs. In rat hepatocytes, Df decreased ferritin synthesis to a similar level in the presence or absence of alcohol. Alcohol increased ferritin synthesis differently in HepG2 cells and in normal rat hepatocyte cultures. In the latter case, the alcohol effect was observed at low concentration. Despite a striking inhibiting effect of Df on ferritin synthesis, in both cellular models a mechanism accounting for increased ferritin synthesis independently of iron is suggested. Globally, these data strongly suggest that hyperferritinemia in chronic alcoholism could be related to the induction of ferritin by alcohol.

Selenocysteylation in eukaryotes necessitates the uniquely long aminoacyl acceptor stem of selenocysteine tRNA(Sec)

Selenocysteine synthesis is achieved on a specific tRNA, tRNA(Sec), which is first charged with serine to yield seryl-tRNA(Sec). Eukaryotic tRNA(Sec) exhibits an aminoacyl acceptor stem with a unique length of 9 base pairs. Within this stem, two base pairs, G5a.U67b and U6.U67, drew our attention, whose non-Watson-Crick status is maintained in the course of evolution either through U6.U67 base conservation or base covariation at G5a.U67b. Single or double point mutations were performed, which modified the identity of either or both of the base pairs. Serylation by seryl-tRNA synthetase was unaffected by substitutions at either G5a.U67b or U6.U67. Instead, and quite surprisingly, changing G5a.U67b and U6.U67 to G5a-C67b/U6.G67 or G5a-C67b/C6-G67 gave rise to a tRNA(Sec) mutant exhibiting a gain of function in serylation. This finding sheds light on the negative influence born by a few base pairs in the acceptor stem of tRNA(Sec) on its serylation abilities. The tRNA(Sec) capacities to support selenocysteylation were next examined with regard to a possible role played by the two non-Watson-Crick base pairs and the unique length of the acceptor stem. It first emerges from our study that tRNA(Sec) transcribed in vitro is able to support selenocysteylation. Second, none of the point mutations engineered at G5a.U67b and/or U6.U67 significantly modified the selenocysteylation level. In contrast, reduction of the acceptor stem length to 8 base pairs led tRNA(Sec) to lose its ability to efficiently support selenocysteylation. Thus, our study provides strong evidence that the length of the acceptor stem is of prime importance for the serine to selenocysteine conversion step.