Deformable image registration with deep network priors: a study on longitudinal PET images

Objective. This paper proposes a novel approach for the longitudinal registration of PET imaging acquired for the monitoring of patients with metastatic breast cancer. Unlike with other image analysis tasks, the use of deep learning (DL) has not significantly improved the performance of image registration. With this work, we propose a new registration approach to bridge the performance gap between conventional and DL-based methods: medical image registration method regularized by architecture (MIRRBA). Approach. MIRRBA is a subject-specific deformable registration method which relies on a deep pyramidal architecture to parametrize the deformation field. Diverging from the usual deep-learning paradigms, MIRRBA does not require a learning database, but only a pair of images to be registered that is used to optimize the network's parameters. We applied MIRRBA on a private dataset of 110 whole-body PET images of patients with metastatic breast cancer. We used different architecture configurations to produce the deformation field and studied the results obtained. We also compared our method to several standard registration approaches: two conventional iterative registration methods (ANTs and Elastix) and two supervised DL-based models (LapIRN and Voxelmorph). Registration accuracy was evaluated using the Dice score, the target registration error, the average Hausdorff distance and the detection rate, while the realism of the registration obtained was evaluated using Jacobian's determinant. The ability of the different methods to shrink disappearing lesions was also computed with the disappearing rate. Main results. MIRRBA significantly improved all metrics when compared to DL-based approaches. The organ and lesion Dice scores of Voxelmorph improved by 6% and 52% respectively, while the ones of LapIRN increased by 5% and 65%. Regarding conventional approaches, MIRRBA presented comparable results showing the feasibility of our method. Significance. In this paper, we also demonstrate the regularizing power of deep architectures and present new elements to understand the role of the architecture in DL methods used for registration.

PERCIST-like response assessment with FDG PET based on automatic segmentation of all lesions in metastatic breast cancer

e13057

Background: In metastatic breast cancer (MBC), treatment response is often assessed with FDG PET per PERCIST which evaluates changes in SULpeak of the single hottest tumor lesion identified on the baseline and follow-up images. PERCIST therefore does not consider tumor heterogeneity. This work aims to compare responses determined with the automatic segmentation of all lesions to response determined manually per PERCIST. Methods: 10 MBC patients (61±14 y/o) undergoing either chemo- or hormonotherapy were randomly selected from the prospective EPICURE study (NCT03958136). A baseline and two follow-up FDG PET were acquired at pre-, early- (1 month) and mid-treatment times for each patient. All metastatic lesions on all images were manually segmented by experts. Using the Advanced Normalization Tools (ANTs) image registration method, we wrapped baseline lesion segmentations to automatically obtain the follow-up ones. These registered segmentations were compared to the ones done manually using standard biomarkers: SULpeak, lesion size and Total Lesion Glycolysis (TLG). Differences between baseline and follow-up images were visually represented by coloring the follow-up segmentations: in green for responsive lesions (decreasing SULpeak) and in red for progressive ones (increasing SULpeak). Two expert physicians were then asked to evaluate treatment response while seeing these colored segmentations. They assessed the FDG PET images in pairs, evaluating for each patient the baseline and one of the corresponding follow-ups in a blinded manner: either the early- or the mid-treatment follow-up. Evaluations were then compared: i) early- vs mid-treatment response and ii) follow-up response vs patient’s clinical outcome. Results: Biomarkers extracted from the registered segmentations were similar to the ones extracted from the manual segmentations, with a Lin correlation coefficient of 0.92, 0.87 and 0.95 for the SULpeak, lesion size and TLG respectively. These findings were obtained within ̃10min, whereas the manual segmentation of the three PET images for any given patient took ̃1h. With the use of colored segmentations, early follow-up evaluations were predictive of mid-treatment response in 65% of the cases. The blinded physicians agreed with the clinical outcomes 85% and 95% of the time for the early- and mid-treatment images respectively. Conclusions: With segmentations automatically derived from ANTs registration, we managed to extract biomarkers that are comparable to the ones obtained with manual segmentations; both segmentations carried similar information. ANTs fast registration and biomarkers computation can make it a useful tool in clinical routine. In addition, lesion coloring helped evaluate treatment response and early-treatment follow-up images were shown to be predictive of mid-treatment response. Clinical trial information: NCT03958136.

Automatic Segmentation of Metastatic Breast Cancer Lesions on 18F-FDG PET/CT Longitudinal Acquisitions for Treatment Response Assessment

Metastatic breast cancer patients receive lifelong medication and are regularly monitored for disease progression. The aim of this work was to (1) propose networks to segment breast cancer metastatic lesions on longitudinal whole-body PET/CT and (2) extract imaging biomarkers from the segmentations and evaluate their potential to determine treatment response. Baseline and follow-up PET/CT images of 60 patients from the EPICUREseinmeta study were used to train two deep-learning models to segment breast cancer metastatic lesions: One for baseline images and one for follow-up images. From the automatic segmentations, four imaging biomarkers were computed and evaluated: SULpeak, Total Lesion Glycolysis (TLG), PET Bone Index (PBI) and PET Liver Index (PLI). The first network obtained a mean Dice score of 0.66 on baseline acquisitions. The second network obtained a mean Dice score of 0.58 on follow-up acquisitions. SULpeak, with a 32% decrease between baseline and follow-up, was the biomarker best able to assess patients' response (sensitivity 87%, specificity 87%), followed by TLG (43% decrease, sensitivity 73%, specificity 81%) and PBI (8% decrease, sensitivity 69%, specificity 69%). Our networks constitute promising tools for the automatic segmentation of lesions in patients with metastatic breast cancer allowing treatment response assessment with several biomarkers.

Upstream modes and antidots poison graphene quantum Hall effect

The quantum Hall effect is the seminal example of topological protection, as charge carriers are transmitted through one-dimensional edge channels where backscattering is prohibited. Graphene has made its marks as an exceptional platform to reveal new facets of this remarkable property. However, in conventional Hall bar geometries, topological protection of graphene edge channels is found regrettably less robust than in high mobility semi-conductors. Here, we explore graphene quantum Hall regime at the local scale, using a scanning gate microscope. We reveal the detrimental influence of antidots along the graphene edges, mediating backscattering towards upstream edge channels, hence triggering topological breakdown. Combined with simulations, our experimental results provide further insights into graphene quantum Hall channels vulnerability. In turn, this may ease future developments towards precise manipulation of topologically protected edge channels hosted in various types of two-dimensional crystals.

Speaking with virtual humans: Assessing social cognition in traumatic brain injury with a second-person perspective task

OBJECTIVE

This study is one of the first to investigate social cognition in participants with traumatic brain injury (TBI) using a task that actively engaged the participant in a real interaction with a partner. Previous results have reported altered social cognition in TBI patients, but social cognition was mostly assessed through traditional tasks involving conscious and deliberate reasoning about characters' mental states (i.e., a third-person perspective). Our goal was to present a new paradigm which allowed the assessment of social cognition in conditions closer to real life meaning that participants were actively engaged in an interaction (i.e., second-person perspective) in order to capture more implicit use of social cognition processes.

METHOD

This study used three tasks to evaluate social cognition. We designed a task, called EVICog, in which participants were engaged in real audio-visual conversations with two virtual humans who expressed emotions and produced speech content that required the participants to make inferences about the characters' mental states. The two other tasks are standard in the literature; they use photographs to test participants' recognition of emotions and short comic strips to test their attribution of intentions.

RESULTS

Our results showed that TBI participants presented a significant deficit of social cognition compared to control participants. The ROC analysis showed that EVICog has a high discrimination power compared to the other tests.

CONCLUSION

These results further confirm that social cognition is altered in TBI participants even in real interactions and further support the use of ecological settings to investigate social cognition.

Program esilence 1.0 - self-regulation program in food education via instagram-loricorps, study protocol

Introduction

Social medias are seen as a risk factor for mental health because they increase body dissatisfaction and decrease self-esteem. This program is based on alimentation and physical well-being by relying on integrated intuitive eating and physical self-esteem. This program, implemented in a community setting use social media (i.e. Instagram-Loricorps), is composed of 12 monthly 180-second video capsule that address themes related to the promotion of body sensations and intuitive movement.

Objectives

The main objective of this study is to evaluate the effects of the program into the physical environment targeting the physical self-perceptions (PSP). Specifically, this study evaluates whether the eSILENCE 1.0 Program improves the level of PSP related to nutrition and explores the changes in the level and variability of the PSP.

Methods

This project is a mixed sequential explanatory study. 300 participants (Experimental Group [EG; N=200], Control Group [CG; N=100]) are targeted. Online nomothetic questionnaires evaluate occupational changes and PSP in relation to alimentation and are completed by the EG and the CG at pre-test, mid-test and post-test. Online idiographic questionnaires assess PSP and are completed by the EG before and after each video capsule and by the CG once a month without viewing the capsules. Following a preliminary analysis, a focus group will be formed to explain and deepen these results. Participants (N=5) will be recruited voluntarily into the EG.

Results

to come.

Conclusions

Analysis of quantitative data will be used to assess the effectiveness of the program and analysis of qualitative data will provide an in-depth understanding of the linkages between the variables.

Disclosure

No significant relationships.

Sequence of cigarette and e-cigarette initiations and daily smoking in adolescents (HBSC 2018)

Background

Electronic cigarette may help adults quit smoking. For adolescents, the concern is whether e-cigarette initiation is a gateway to subsequent smoking. Our objectives were to describe the sequence of conventional cigarette and e-cigarette initiations among adolescents who had already used both products, and to analyse the current smoking behaviour according to the first experienced product.

Methods

Analyses were based on a two-stage random sample of 9,937 12-20-year-old adolescents included in the French-speaking Belgian 2018 Health Behaviour in School-aged Children cross-sectional survey. Cigarette and e-cigarette initiations and its sequence, current daily smoking and other characteristics were collected through a self-administered questionnaire. Associations, adjusted for demographic data, were estimated using logistic regression and weighted. Sampling design was considered in analyses.

Results

In 2018, 66.0% of adolescents reported never having tried a cigarette and e-cigarette, 8.1% having experimented cigarettes only, 9.2% e-cigarette only and 16.6% having experimented both. Among adolescents who tried both products, eight out of ten smoked cigarettes before trying the e-cigarette (78.2%). In the whole sample, 6.8% of adolescents were smoking every day. Daily smoking was observed in 19.8% of adolescents who initiated e-cigarette and cigarettes and in 6.4% of those who initiated cigarettes only. Adolescents who first smoked cigarettes were more likely to further smoke daily (aOR: 2.48 [1.69-3.64]) than those who first used e-cigarette. The risk of daily smoking was not different between adolescents who first used e-cigarette compared with those who tried cigarettes only (aOR: 1.23 [0.76-2.00]).

Conclusions

In French-speaking Belgium, conventional cigarette was the first step in the initiation and continuation of tobacco smoking. These findings help understand smoking patterns among adolescents and will support the development of smoking prevention strategies.

Key messages

Our findings suggest that health promotion interventions should remain focused on conventional cigarette. Based on a cross-sectional study, they should however be confirmed by prospective studies.

Sexual maturation in girls: association with physical activity and sedentary behaviour

Introduction

During adolescence, physical activity tends to decline, especially among girls. Adolescent inactivity is due in part to biological factors, among which pubertal development may play a role. Our aim was to study in girls, the relationship of sexual maturation based on menarche with physical activity and sedentary behaviour.

Methods

Analyses were based on a two-stage random sample of 3,911 10-15-year-old girls included in the 2018 cross-sectional Health Behaviour in School-aged Children survey carried out in French-speaking schools. Menarche, sufficient levels of physical activity (PA) (global PA: at least 60 min. of moderate- to vigorous-intensity PA daily, and vigorous PA: at least 3 times/week), sedentary week time based on all-screen use duration (SWT; categories based on tertiles), and sociodemographic characteristics were self-reported. Multilevel multiple binary (for PA) and multinomial (for SWT) logistic regressions were performed, stratified by age group (≤12.5 years vs. >12.5 years).

Results

Twenty percent of girls aged ≤ 12.5 years and 85.0% of girls aged > 12.5 years have had their first period. Within the group aged ≤12.5, post-menarcheal girls were more likely to spend long SWT (≥8h/day) than pre-menarcheal girls (vs. short SWT (<4h/day): aRRR= 1.74 [1.27-2.37]; NS for moderate SWT (4-7h/day)). Within those aged >12.5, post-menarcheal girls were less likely to engage in sufficient vigorous PA (aOR=0.76 [0.59-0.98]) than pre-menarcheal girls. Moreover, they were more likely to spend moderate (aRRR=1.70 [1.19-2.42]) and long SWT (aRRR=2.74 [1.94-3.88]) than pre-menarcheal girls of same ages. Additional adjustments for age modified the strength of associations.

Conclusions

Our results suggest that during adolescence, the physiological changes induced by sexual maturation may contribute to the decline in physical activity (in > 12.5 years), and in the increase in sedentary behaviour in girls. Potential confounding by age will be explored further.

Key messages

Development of strategies aimed at improving physical activity among adolescent girls should take into account, among other aspects, pubertal development. Specific interventions, targeting pubescent girls, should also be developed to reduce screen time in order to prevent its potential negative consequences.

[Secondary facial recontouring with micro-porous titanium implants]

Facial recontouring has always been a longstanding objective of esthetic or reconstructive surgery. Most often it uses two types of surgical techniques: autologous and alloplastic. In that regard, different surgical techniques have been proposed to enhance facial recontouring.

MATERIALS AND METHODS

Through 5 clinical case reports and a literature review, this article explores the use of allopastic microporous titanium implants in secondary volumetric corrections of the face.

RESULTS

There is a current lack of evidence regarding the use of microporous titanium implants in volumetric corrections of the face, most papers reporting their use in post-traumatic or post-surgical cranio-facial defects repair.

DISCUSSION

Pros and cons of such implants are discussed in association with the usefulness of this surgical technique in daily surgical practice.

A rare ectopic localization of pleomorphic adenoma

INTRODUCTION

Pleomorphic adenoma (PA) is the most common benign salivary gland tumor, frequently affecting the major salivary glands but also the palatal or labial minor salivary glands. Pleomorphic adenomas affecting the retromolar trigone have seldom been reported with only few cases described in the literature.

OBSERVATION

We present the case of a young female patient who presented with this rare localization of pleomorphic adenoma and its subsequent management.

DISCUSSION

Pleomorphic adenoma of the retromolar trigone is a rare occurrence. Nevertheless, when faced with a swelling of the retromolar trigone, a diagnosis of pleomorphic adenoma should not be omitted from the differential.

Comparing impact on the family and insurance coverage in children with cerebral palsy and children with another special healthcare need

BACKGROUND

Families and caregivers of children with special healthcare needs (CSHCN) often experience financial difficulties, have unmet physical and mental health needs, and are at increased risk of marital problems due to the stress caused by carrying for their child. Within the larger population of CHSCN, young people with cerebral palsy (CP) have more unmet needs due to the complexity and potential severity of the disability. The purpose of this study was to identify factors associated with differences in insurance coverage and impact on the family of children with CP and other CHSCN.

METHODS

The data were taken from the National Survey of Children with Special Health Care Needs, which was designed to examine state- and national-level estimates of CSHCN. Three variables examined differences in insurance coverage between those children diagnosed with CP versus all other CSHCN: insurance coverage for the previous year, current insurance coverage, and adequacy of insurance coverage. Four variables representing different indicators of family impact were used to assess differences between children with CP versus all other CSHCN: out-of-pocket expenses for healthcare, family financial burden, hours per week that family members spent caring for the child, and impact on family work life.

RESULTS

The results of this study showed significant differences between households with a child with CP and a child with another health special need in terms of insurance coverage, indicating a tendency of children with CP to be insured the entire year. As for the impact on the family in households with children with CP versus other CSHCN, there were significant differences in all four variables that were analysed.

CONCLUSIONS

There is limited evidence highlighting differences between the impact of caring for a child with CP and caring for other CSHCN. Caring for a child with CP has a significant impact on the family, despite insurance coverage.

Effects of cognitive impairment on prosodic parameters of speech production planning in multiple sclerosis

Cognitive impairment (CI) affects 40-65% of patients with multiple sclerosis (MS). CI can have a negative impact on a patient's everyday activities, such as engaging in conversations. Speech production planning ability is crucial for successful verbal interactions and thus for preserving social and occupational skills. This study investigates the effect of cognitive-linguistic demand and CI on speech production planning in MS, as reflected in speech prosody. A secondary aim is to explore the clinical potential of prosodic features for the prediction of an individual's cognitive status in MS. A total of 45 subjects, that is 22 healthy controls (HC) and 23 patients in early stages of relapsing-remitting MS, underwent neuropsychological tests probing specific cognitive processes involved in speech production planning. All subjects also performed a read speech task, in which they had to read isolated sentences manipulated as for phonological length. Results show that the speech of MS patients with CI is mainly affected at the temporal level (articulation and speech rate, pause duration). Regression analyses further indicate that rate measures are correlated with working memory scores. In addition, linear discriminant analysis shows the ROC AUC of identifying MS patients with CI is 0.70 (95% confidence interval: 0.68-0.73). Our findings indicate that prosodic planning is deficient in patients with MS-CI and that the scope of planning depends on patients' cognitive abilities. We discuss how speech-based approaches could be used as an ecological method for the assessment and monitoring of CI in MS.

Neuropathic pain in the orofacial region: The role of pain history. A retrospective study

INTRODUCTION

Orofacial neuropathic pain is often difficult to treat, mostly because of still unclear underlying mechanisms. The occurrence of such neuropathic pain varies depending on different factors, of which preexisting preoperative pain seems to be of high importance. The aim of this study was thus to test the hypothesis that prior history of pain could indeed be considered a risk factor for the development of orofacial neuropathic pain in the same region.

METHODS

The study was performed in the dental department of the Groupe Hospitalier Pitié-Salpêtrière (GHPS) in Paris, France. We investigated the presence of prior inflammatory pain before development of orofacial neuropathic pain in 56 patients. For each patient file, the following items were collected: age, gender; medical history; diagnosis; description of the pain (at time of consultation); presence or absence of prior dental treatment; date and type of dental treatment received.

RESULTS

41 patients (73%) of orofacial neuropathic pain patients had a history of pain compatible with an inflammatory condition; 4% (n=2) did not report any prior pain and 23% (n=13) could not remember. Among the patients with documented history of pain prior to neuropathy, 88% (n=36) received surgical treatment; 61%, (n=25) endodontic treatment and 22%, (n=9) restorative treatment. All eventually received endodontic treatment or tooth extraction. These dental treatments are compatible with the hypothesis of prior inflammatory pain in these patients.

CONCLUSION

These results support the hypothesis that prior inflammatory pain could favor the development of orofacial neuropathic pain. Prevention and treatment of inflammatory trigeminal pain may therefore play a key role in preventing future neuropathic pain development.

Hedgehog Pathway-Mediated Vascular Alterations Following Trigeminal Nerve Injury

Whereas neurovascular interactions in spinal neuropathic pain models have been well characterized, little attention has been given to such neurovascular interactions in orofacial neuropathic pain models. This study investigated in male Sprague-Dawley rats the vascular changes following chronic constriction injury (CCI) of the infraorbital nerve (IoN), a broadly validated preclinical model of orofacial neuropathic pain. Following IoN-CCI, an early downregulation of tight junction proteins Claudin-1 and Claudin-5 was observed within the endoneurium and perineurium, associated with increased local accumulation of sodium fluorescein (NaFlu) within the IoN parenchyma, as compared with sham animals. These events were evidence of local blood-nerve barrier disruption and increased vascular permeability. A significant upregulation of immunocytes (CD3, CD11b) and innate immunity (TLR2, TLR4) mRNA markers was also observed, suggestive of increased local inflammation. Finally, a significant downregulation of Hedgehog pathway readouts Patched-1 and Gli-1 was observed within the IoN after CCI and local injections of cyclopamine, a Hedgehog pathway inhibitor, replicated in naïve rats the molecular, vascular, and behavioral changes observed following IoN-CCI. These results suggest a major role of Hedgehog pathway inhibition in mediating local increased endoneurial and perineurial vascular permeability following trigeminal nerve injury, thus facilitating immunocytes infiltration, neuroinflammation development, and neuropathic pain-like aversive behavior.

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine: Brussels, Belgium. 15-18 March 2016

[This corrects the article DOI: 10.1186/s13054-016-1208-6.].

Characteristics of current tasks that contribute to mentalizing judgments: does the engagement of the participants in the social interaction matter? Comment on Achim et al. (2013)

In a recent article, Achim et al. (2013) discussed the different sources of information that contribute to mentalizing judgments in current theory-of-mind (ToM) tasks. The authors rightly emphasized the dynamic aspect of real-life social interaction, suggesting that taking account of the ongoing changes occurring during social interaction would make ToM tasks more ecological. They proposed a framework (i.e., the Eight Sources of Information Framework) that specifies the 8 sources of information we get from the environment and/or from our memories to attribute mental states to others. Nevertheless, we believe that a central aspect of ToM is missing in this framework: the engagement (or not) of the participant in the social interaction during ToM assessment. Indeed, this framework fails to consider how the participant who takes part in the ToM task manages this information, depending on the fact that he or she is involved in the interaction or not and how the information concerning the agent may impact the participant attribution of mental states. We reviewed several arguments and results from the ToM literature suggesting that merely observing a social interaction is not equivalent to participating in an interaction in terms of cognitive processes involved in the attribution of mental states to others.

Using memories to understand others: the role of episodic memory in theory of mind impairment in Alzheimer disease

Theory of mind (TOM) refers to the ability to infer one's own and other's mental states. Growing evidence highlighted the presence of impairment on the most complex TOM tasks in Alzheimer disease (AD). However, how TOM deficit is related to other cognitive dysfunctions and more specifically to episodic memory impairment - the prominent feature of this disease - is still under debate. Recent neuroanatomical findings have shown that remembering past events and inferring others' states of mind share the same cerebral network suggesting the two abilities share a common process .This paper proposes to review emergent evidence of TOM impairment in AD patients and to discuss the evidence of a relationship between TOM and episodic memory. We will discuss about AD patients' deficit in TOM being possibly related to their difficulties in recollecting memories of past social interactions.

Selection of anionic exchange resins for removal of natural organic matter (NOM) fractions

Early elimination of natural organic matter (NOM) by ion exchange (IEX) in water treatment is expected to improve subsequent water treatment processes and the final drinking water quality. Nine anionic exchange resins were investigated to remove NOM and specific NOM fractions determined by liquid chromatography in combination with organic carbon detection (LC-OCD) and fluorescence excitation-emission matrices (EEM). Breakthrough of NOM was predicted by model calculations using Freundlich isotherms and IEX rate experiments. The time to breakthrough varied from 4 to 38 days. Removal of specific NOM fractions proved to vary considerably for the different types of IEX resins, ranging from 1% to almost 60%. The removal of NOM fractions, specifically humic substances, increased with an increase in water content of the investigated IEX resins and with a decrease in resin size. The best-performing IEX resins consisted of the smallest resins and/or those with the highest water content. The worst-performing IEX resins reflected the highest exchanging capacities and the lowest water contents.

NUDC expression during amphibian development

To identify gene products important for gastrulation in the amphibian Pleurodeles waltl, a screen for regional differences in new protein expression at the early gastrula stage was performed. A 45 kDa protein whose synthesis was specific for progenitor endodermal cells was identified. Microsequencing and cDNA cloning showed that P45 is highly homologous to rat NUDC, a protein suggested to play a role in nuclear migration. Although PNUDC can be detected in all regions of the embryo, its de novo synthesis is tightly regulated spatially and temporally throughout oogenesis and embryonic development. New PNUDC synthesis in the progenitor endodermal cells depends on induction by the mesodermal cells in the gastrula. During development, PNUDC is localized in the egg cortical cytoplasm, at the cleavage furrow during the first embryonic division, around the nuclei and cortical regions of bottle cells in the gastrula, and at the basal region of polarized tissues in the developing embryo. These results show for the first time the expression and compartmentalization of PNUDC at distinct stages during amphibian development.

Overexpression, purification and photoaffinity labeling with a 3H-analogue of norfloxacin, of the GyrA and GyrB subunits of the DNA gyrase

In spite of much work on DNA gyrase and quinolones for many years, our knowledge of the molecular basis of quinolone-gyrase action is still incomplete. We designed a photoaffinity labeling reagent for the quinolone target, and synthesized a norfloxacin analogue with an azide function which, under UV irradiation, becomes covalently linked to its target. For that, a large amount of purified gyrase was needed. Both subunits were purified using exclusion and affinity chromatography. A plasmid was used that allowed the overproduction of GyrA as a fusion-protein with six histidine residues at its carboxy-terminal domain. GyrA-(His)6 was purified after chromatography on a nickel-containing column, and native GyrB after chromatography on immobilized novobiocin. Reconstituted DNA gyrase (A2B2) had supercoiling activity. Photoaffinity labeling showed covalent binding of the 3H-photoaffinity analogue of norfloxacin to the gyrase-DNA complex, and mainly to the GyrA. The specific binding site remains to be explored.

Young age and HLA markers enhance the risk of progression to type 1 diabetes in antibody-positive siblings of diabetic children

The contribution of autoantibodies, HLA markers and age to long-term estimates of risk of type 1 diabetes were examined after a median of 11 years (range 7.5-14) during the follow-up in a cohort of 234 siblings (aged 2-29 years) of French children with recent-onset type 1 diabetes, of whom 12 (5.1%) developed diabetes. We evaluated islet cell antibodies (ICA) by indirect immunofluorescence and autoantibodies to insulin (IAA), to the 65 kDa isoform of glutamic acid decarboxylase (GADA) and to the IA-2 protein (IA-2A) by radioligand assay in sequential serum samples. Among the 234 siblings of type 1 diabetic patients screened, 27 were positive for at least one antibody, 11 of whom progressed to develop type 1 diabetes during the follow-up (sensitivity, 92%, predictive value, 41%). Among the four antibodies tested individually, ICA had the highest sensitivity (83%) but a poor predictive value (59%) and IA-2A the highest predictive value (70%). IAA and GADA both exhibited poor sensitivity and predictive value. Combinations of antibodies achieved better predictive values than antibodies tested individually. Satisfactory predictive values were obtained for the combination of GADA with IA-2A (83%), for any combination of at least two antibodies other than ICA (70%) and for the combination of ICA with at least one other antibody (69%). The risk estimates were highest in the presence of three or four antibodies, whether comprising ICA or not, but with a concomitant loss of sensitivity. For most antibody combinations, cumulative risks showed progression from approximately 50% after 5 years to 100% after 13 years. HLA-DR3/4 was significantly more frequent in siblings developing type 1 diabetes than in non-diabetic siblings (9/12 vs. 39/217, relative risk (RR)=14, P</=0.0001). The predictive value of HLA-DR3/4 was low (19%); however, taking into account the presence of HLA-DR3/4 in subjects who were positive for more than one antibody resulted in a higher predictive value (67%, vs. 20% in non-DR3/4 subjects, P</=0.02). In addition, siblings developing diabetes were younger at entry than those who did not (mean =7.5 +/-1.23 vs. 12.5 +/-0.39 years, respectively; P</=0.01). Ten of 12 were aged less than 10 years compared with 106/222 non-diabetic siblings (RR =5.4, P</=0.03). Moreover, younger age was associated with a more rapid development of type 1 diabetes. In conclusion, our results show that the combination of IAA, GADA and IA-2A autoantibodies in sequential serum samples is satisfactory for the identification of subjects at risk of developing type 1 diabetes. Additional factors such as younger age and HLA-DR3/4 as markers of progression to disease may contribute to more efficient prediction in antibody positive subjects.

Cell-cycle-dependent nuclear translocation of HSP70 in amphibian embryonic cells

Using immunocytochemical methods, we analyzed the localization of the HSP70 protein constitutively expressed during embryogenesis in the amphibian Pleurodeles waltl. Our results provide evidence for nuclear transfer of the protein during gastrulation, and particularly for predominant nuclear labeling in gastrula internalized cells. Using two inhibitors of DNA replication -hydroxyurea (HUA) and aphidicolin- or/and an inhibitor of transcription -actinomycin D- applied to embryos, we demonstrated that nuclear transfer of HSP70 is related to the transcriptional activity of the cells during the early S phase of the cell cycle.

Evidence for specific RNA/protein interactions in the differential segment of the W sex chromosome in the amphibian Pleurodeles waltl

Pleurodeles exhibits a ZZ/ZW system of GSD (genotype sex determination). However, the Z and W sex chromosomes appear to be morphologically identical. A short RNA sequence is described that was specifically bound to lampbrush loops in the differential segment of the sexual bivalent IV. The distribution of these labeled loops in experimentally produced ZZ and WW females enabled us to demonstrate that such labeled loops were perfectly correlated with the W chromosome. Therefore, this RNA sequence constitutes an excellent marker for the W differential segment. Furthermore, analysis of the labeled loops under various experimental conditions suggested that their labeling is caused by specific interactions between this RNA sequence and lampbrush loop-associated proteins (RNA/protein interactions). North-western assays revealed that nuclear polypeptide(s) of 65 kDa could be responsible for such binding.

Conditions for a heat shock response during oogenesis and embryogenesis of the amphibian Pleurodeles waltl

The optimal conditions capable of inducing an increase in HSP70 neosynthesis during development of the urodele amphibian Pleurodeles waltl were determined in this study. These conditions depend on temperature, heat shock duration and recovery duration. In oocytes, a heat shock response was repeatedly obtained at 37 degrees C for 15 min followed by 1 h recovery. These results provided evidence for heat shock response at every stage considered. An increase in HSP70 synthesis was noted throughout oogenesis, but it did not lead to an increase in the amount of soluble HSP70, except for stage VI oocytes. Such results suggest that from stage II to stage IV oocytes, an equilibrium occurs between the HSP70 used and the HSP70 neosynthesized. In contrast, in stage VI oocytes, heat shock led to overproduction of HSP70. During early development, the heat shock response was repeatedly obtained only from the gastrula stage with a 37 degrees C shock and a 15 min duration of treatment. Surprisingly, during cleavage stage, the soluble HSP70 total amount increased after heat shock at a time when no HSP70 neosynthesis occurred.

Sequence analysis, purification, and study of inhibition by 4-quinolones of the DNA gyrase from Mycobacterium smegmatis

We determined the nucleotide sequence of a 6-kb DNA region harboring the recF, orf192, gyrB, and gyrA genes from Mycobacterium smegmatis mc(2)155. The amino acid sequences deduced from gyrA and gyrB displayed 89 and 86% identity, respectively, with the DNA gyrase from Mycobacterium tuberculosis, and 67 and 65% identity, respectively, with that from Streptomyces coelicolor. An open reading frame encoding the C-terminal region of the M. smegmatis RecF polypeptide was found upstream from gyrB and was 57% identical to the open reading frame encoding the C-terminal region of the S. coelicolor RecF protein. The gene orf192 was identified between recF and gyrB and was 39% identical to orf191 found in S. coelicolor in the recF-gyrB region. The M. smegmatis DNA gyrase, which was purified by affinity chromatography on novobiocin-Sepharose, consisted of two polypeptides with apparent molecular masses of 98 and 80 kDa. Determination of the N-terminal amino acid sequence of the B subunit confirmed GTG as the start codon in gyrB. Analysis of the supercoiling activity of the enzyme indicated that the M. smegmatis DNA gyrase was characterized by a specific activity equivalent to that of the Escherichia coli DNA gyrase. Inhibition of this activity by 4-quinolones was investigated by determining the 50% inhibitory concentrations (IC50S) of nalidixic acid, ofloxacin, and ciprofloxacin. The results indicated that the inhibitory activities of these drugs against the M. smegmatis DNA gyrase were markedly lower than those previously reported for the E. coli DNA gyrase. The results also suggested that the higher levels of activity of ofloxacin and ciprofloxacin against M. smegmatis (MICs, 0.5 to 1 microgram/ml), in contrast to that of nalidixic acid (MIC, 256 micrograms/ml), could be related to the higher inhibitory activities of fluoroquinolones against the DNA gyrase from this species (IC50S, 7 to 14 micrograms/ml) compared with that of nalidixic acid (IC50, 1,400 micrograms/ml).

Inheritance and genetic mapping of self-incompatibility in Coffea canephora Pierre

Cross-compatibility behaviour of doubled haploid (DH) and hybrid genotypes of Coffea camphora was established using both phenotypic bioassay and in situ seed-set examination. The availability of DHs provided the opportunity of working with genetically homogenous pollen and female parents. The aniline blue fluorescence (ABF) method was applied to detect callose accumulation in pollen and pistil. Clear cross-compatibility/incompatibility situations were observed and confirmed by in situ seed-set analysis. Cross-compatibility analysis of hybrid combinations involving different DHs corroborated the crossing behaviour observed at the DH level. Expression of the self-incompatibility system did not appear to be affected by the low vigour of the DH. The crossing-behaviour distribution observed within DHs derived from clone IF200 confirmed that self-incompatibility in C. canephora is a gametophytic self-incompatibility system controlled by a single locus (S-locus). Reduced seed-set developments following incompatible crosses may indicate the occurrence of pseudo-incompatibility. Molecular marker linkage analysis showed that the S-locus is associated with an RFLP marker on linkage group 9. The availability of a linked DNA marker should facilitate the genetic analysis of self-incompatibility in relation to coffee breeding programmes.

Does the chaperone heat shock protein hsp70 play a role in the control of developmental processes?

Expression of an hsp70 gene strictly inducible in somatic cells and constitutively expressed during oogenesis was investigated during embryogenesis of the amphibian Pleurodeles waltl. Results from Northern hybridization experiments and RNase protection assays provided evidence for the presence of inducible hsp70 mRNA under normal conditions at every embryonic stage. Immunoblotting of embryo proteins separated by 2D-electrophoresis provided evidence for the presence of a single polypeptide of about 74 kDa likely to be an HSP70-related protein, from unfertilized egg to tailbud stage. Immunocytological analysis showed that HSP70-related proteins were localized in the cytoplasm of all blastomeres. It also pointed out that nuclear transfer of the protein occurs in certain cells, precisely at the time of their invagination and subsequent internalization during normal Pleurodeles development. Such nuclear transfer involves involuting mesodermal cells in the blastopore region at the time of gastrulation. It also involves neurodermic cells at the time of neural tube closure. Interestingly, in exogastrulas nuclear transfer did not occur in cells which could no longer invaginate. Such behavior of HSP70-related proteins led us to suggest that they are involved in the control of nuclear activity associated with important developmental events such as cellular internalization processes. Such a role may be a direct consequence of HSP70-related protein functional properties as molecular chaperones.

Evidence for a 90 kDa heat-shock protein gene expression in the amphibian oocyte

In order to study expression of a 90-kDa heat-shock protein during amphibian oogenesis at physiological temperature, we isolated a Pleurodeles waltl hsc90 cDNA by screening an ovarian cDNA library with a chicken hsp90 cDNA probe. The cDNA thus obtained--named Pw90--shows a high homology level with the hsp90 gene in other species. RNase protection analysis led us to conclude that this sequence is part of the cognate gene hsc90 and is constitutively expressed in oocytes. Furthermore, results of quantitative Northern blot analysis, as well as in situ hybridizations on oocyte sections or lampbrush chromosome spreads, provide evidence for expression of hsc90 transcripts at every stage of oogenesis. Moreover, they point to the fact that an accumulation of transcripts occurs very early in oogenesis. Simultaneously, the expression of HSC90-related protein was analyzed on Western blots using a monoclonal antibody (AC88) and a polyclonal antibody (AP90Ct) raised against the Pleurodeles C-terminal part of HSC90. We provide evidence for a net accumulation of HSC90-related protein in oocytes. Immunolocalization shows that a nuclear transfer occurs in the course of oogenesis and leads to a concentration equilibrium between cytoplasm and nucleus in stage VI oocytes.

[Current status of resistance of bacteria to pefloxacin in hospital units. Cross resistance with ofloxacin and ciprofloxacin. Results of a multicenter study]

The antibacterial activities of pefloxacin (PEF), ofloxacin (OFL), ciprofloxacin (CIP) were measured by agar diffusion (5 micrograms strength disks) against 6370 non duplicate clinical isolates collected in November 1991 in 40 hospitals from various areas in France. The MICs of PEF, OFL and CIP were determined by agar dilution against intermediate or resistant strains to one of the three antibiotics (inhibition zone < 16 mm for PEF, OFL, < 19 mm for CIP). In the Enterobacteriaceae the overall incidence of resistance to PEF (MIC > 4 mg/l) was 8% with important variations between the different species: E. coli 2%, Salmonella 0%, E. cloacae 9%, K. pneumoniae 21%, P. mirabilis 13%, P. vulgaris 3%, M. morganii 5%, Providencia 61%, S. marcescens 55%. Among S. aureus, the incidence of resistance was 3% for the methicillin-susceptible strains and 86% for the methicillin-resistant strains. The same applied to coagulase negative Staphylococci: methicillin-susceptible 9%, methicillin-resistant 62%. The frequency of the resistant strains was high among P. aeruginosa: 40% and A. baumanii: 83%. A high degree of correlation was observed between the MICs of PEF, OFL and CIP for all the bacterial species: r = 0.8 - 0.9. No major discrepancies were noted between the clinical categorizations of the activities of the three antibiotics for the different species except for P. aeruginosa: 4% of the strains were resistant to pefloxacin and susceptible to ciprofloxacin.

Transcription of amphibian lampbrush chromosomes is disturbed by microinjection of HSP70 monoclonal antibodies

To investigate the possible involvement of HSP70 in nuclear transport of proteins associated with the transcription process in amphibian oocyte lampbrush chromosomes, we examined the effect of anti-HSP70 mouse monoclonal antibodies on the transcriptional activity of lampbrush chromosomes. When injected into the oocyte cytoplasm, anti-HSP70 induced disorganization followed by retraction of chromosomal lateral loops. This retraction reflected inhibition of transcription, which was confirmed by our electron microscopic observations. At the same time, while nucleoli were morphologically disorganized, nucleolar transcription persisted. These modifications were completely reversible. In contrast, no modifications were observed when antibodies were directly microinjected into nuclei. Similar observations were registered at the level of lampbrush chromosomes when wheat germ agglutinin was injected into oocyte cytoplasm. All of these results suggest that HSP70 mediates the nuclear transport of proteins involved in the lampbrush chromosome transcriptional process.

Vascular responsiveness in young, diabetic, and aging hyperinsulinemic rats

The purpose of this study was to compare vascular responsiveness in young (12 week old), aging hyperinsulinemic-glucose intolerant (52 weeks old) and diabetic (streptozotocin; 14 weeks old) rats. Aortic rings with and without endothelium were maintained in organ chambers for isometric tension recording. The contractile response to KCl was significantly enhanced in aortae from diabetic animals when compared to the responses obtained in young and old ones. The contractile response to norepinephrine or U46619, was significantly shifted to the right in the aortae from aging animals, however the aortae from these hyperinsulinemic rats were hyperresponsive to serotonin. Acetylcholine and ADP provoked an endothelium-dependent relaxation which was markedly depressed in the aortae from diabetic animals. The relaxation to ADP was selectively inhibited in the aging animals. The effect of sodium-nitroprusside was not significantly different in the three groups. Isoproterenol and forskolin induced endothelium-independent relaxation. Isoproterenol responses were inhibited in aging and diabetic animals, however the forskolin-relaxation was inhibited only in the aortae from aging animals. These results suggest that in two models of diabetes (i.e. Type I insulin-dependent and type II non insulin-dependent) vascular responsiveness is differently affected. Aging hyperinsulinemic animals present a selective hyperresponsiveness to serotonin, a selective dysfunction of ADP-induced endothelium-dependent relaxation and smooth muscle adenylate cyclase deficit. In diabetic animals a beta adrenergic hyporesponsiveness, not linked to adenylate-cyclase dysfunction, and non-selective depression of endothelium-dependent responses can be observed.