Stigma resistance is associated with advanced stages of personal recovery in serious mental illness patients enrolled in psychiatric rehabilitation.

BACKGROUND: Stigma resistance (SR) is defined as one's ability to deflect or challenge stigmatizing beliefs. SR is positively associated with patient's outcomes in serious mental illness (SMI). SR appears as a promising target for psychiatric rehabilitation as it might facilitate personal recovery. OBJECTIVES: The objectives of the present study are: (i) to assess the frequency of SR in a multicentric non-selected psychiatric rehabilitation SMI sample; (ii) to investigate the correlates of high SR. METHODS: A total of 693 outpatients with SMI were recruited from the French National Centers of Reference for Psychiatric Rehabilitation cohort (REHABase). Evaluation included standardized scales for clinical severity, quality of life, satisfaction with life, wellbeing, and personal recovery and a large cognitive battery. SR was measured using internalized stigma of mental illness - SR subscale. RESULTS: Elevated SR was associated with a preserved executive functioning, a lower insight into illness and all recovery-related outcomes in the univariate analyses. In the multivariate analysis adjusted by age, gender and self-stigma, elevated SR was best predicted by the later stages of personal recovery [rebuilding; p = 0.004, OR = 2.89 (1.36-4.88); growth; p = 0.005, OR = 2.79 (1.30-4.43)). No moderating effects of age and education were found. CONCLUSION: The present study has indicated the importance of addressing SR in patients enrolled in psychiatric rehabilitation. Recovery-oriented psychoeducation, metacognitive therapies and family interventions might improve SR and protect against insight-related depression. The effectiveness of psychiatric rehabilitation on SR and the potential mediating effects of changes in SR on treatment outcomes should be further investigated in longitudinal studies.

Being parent is associated with suicidal history in people with serious mental illness enrolled in psychiatric rehabilitation.

Parenting is a central life experience that could promote recovery in people with Serious Mental Illness (SMI). It could also be challenging for parents with SMI and result in poor recovery-related outcomes. Parenting is often overlooked in psychiatric rehabilitation. The objectives of the present study were to identify the characteristics and needs for care of mothers and fathers with SMI enrolled in a multicentric non-selected psychiatric rehabilitation SMI sample. We consecutively recruited 1436 outpatients from the French National Centers of Reference for Psychiatric Rehabilitation cohort (REHABase). The evaluation included standardized scales for clinical severity, psychosocial function, quality of life and satisfaction with life, wellbeing, personal recovery and a broad cognitive battery. We found that parenting was associated to suicidal history in mothers and fathers with SMI. In the multivariate analysis, being mother was best explained by insight (p < 0.015, adjusted OR = 0.76 [0.59-0.90]), current age (p < 0.001, aOR = 1.13 [1.07-1.21]), education level (p = 0.008; aOR = 0.12 [0.02-0.53]) and family accommodation (p = 0.046, aOR = 0.19 [0.03-0.84]). Being father was best explained by suicidal history (p = 0.005, aOR = 3.85 [1.51-10.10]), marital status (in relationship, p < 0.001; aOR = 7.81 [2.73-23.84]), satisfaction with family relationships (p = 0.032, aOR = 1.22 [1.02-1.47]) and current age (p < 0.001, aOR = 1.16 [1.10-1.23]). In short, parenting was associated to increased history of suicide attempt in mothers and fathers with SMI. Mothers and fathers with SMI may have unique treatment needs relating to parenting and recovery-related outcomes. The implementation of interventions supporting the needs of parents with SMI in psychiatric rehabilitation services could improve parent and children outcomes.

Self-stigma in serious mental illness and autism spectrum disorder: Results from the REHABase national psychiatric rehabilitation cohort.

BACKGROUND: Self-stigma is a major issue in serious mental illness (SMI) and is negatively associated with patient outcomes. Most studies have been conducted in schizophrenia (SZ). Less is known about self-stigma in other SMI and autism spectrum disorder (ASD). The objectives of this study are: (i) to assess the frequency of self-stigma in a multicentric nonselected psychiatric rehabilitation SMI and ASD sample; and (ii) to investigate the correlates of elevated self-stigma in different SMI conditions and in ASD. METHODS: A total of 738 SMI or ASD outpatients were recruited from the French National Centers of Reference for Psychiatric Rehabilitation cohort (REHABase). Evaluations included sociodemographic data, illness characteristics, and standardized scales for clinical severity, quality of life, satisfaction with life, wellbeing, personal recovery, a large cognitive battery, and daily functioning assessment. RESULTS: 31.2% of the total sample had elevated self-stigma. The highest prevalence (43.8%) was found in borderline personality disorder and the lowest (22.2%) in ASD. In the multivariate analysis, elevated self-stigma was best predicted by early stages of personal recovery (moratorium, p = 0.001, OR = 4.0 [1.78-8.98]; awareness, p = 0.011, OR = 2.87 [1.28-6.44]), history of suicide attempt (p = 0.001, OR = 2.27 [1.37-3.76]), insight (p = 0.002, OR = 1.22 [1.08-1.38]), wellbeing (p = 0.037, OR = 0.77 [0.60-0.98]), and satisfaction with interpersonal relationships (p < 0.001, OR = 0.85 [0.78-0.93]). CONCLUSIONS: The present study has confirmed the importance of addressing self-stigma in SMI and ASD patients enrolled in psychiatric rehabilitation. The effectiveness of psychiatric rehabilitation on self-stigma and the potential mediating effects of changes in self-stigma on treatment outcomes should be further investigated.

Adherence to treatment guidelines in clinical practice for using electroconvulsive therapy in major depressive episode.

BACKGROUND: ECT is the most effective treatment of major depressive episode (MDE) but remains a neglected treatment. The French Society for Biological Psychiatry and Neuropsychopharmacology aimed to determine whether prescribing practice of ECT followed guidelines recommendations. METHODS: This multicenter, retrospective study included adult patients with major depressive disorder (MDD) or bipolar disorder (BD), who have been treated with ECT for MDE. Duration of MDE and number of lines of treatment received before ECT were collected. The reasons for using ECT, specifically first-line indications (suicidality, urgency, presence of catatonic and psychotic features, previous ECT response, patient preference) were recorded. Statistical comparisons between groups used standard statistical tests. RESULTS: Seven hundred and forty-five individuals were included. The mean duration of MDE before ECT was 10.1 months and the mean number of lines of treatment before ECT was 3.4. It was significantly longer for MDD single episode than recurrent MDD and BD. The presence of first-line indications for using ECT was significantly associated to shorter duration of MDE (9.1 vs 13.1 months, p<0.001) and lower number of lines of treatment before ECT (3.3 vs 4.1, p<0.001). LIMITATIONS: This is a retrospective study and not all facilities practicing ECT participated that could limit the extrapolation of the results. CONCLUSION: Compared to guidelines, ECT was not used as first-line strategy in clinical practice. The presence of first-line indications seemed to reduce the delay before ECT initiation. The improvements of knowledge and access of ECT are needed to decrease the gap between guidelines and clinical practice.

Efficacy of shared decision-making on treatment adherence of patients with bipolar disorder: a cluster randomized trial (ShareD-BD).

BACKGROUND: Shared decision-making (SDM) is a model of interaction between doctors and patients in which both actors contribute to the medical decision-making process. SDM has raised great interest in mental healthcare over the last decade, as it is considered a fundamental part of patient-centered care. However, there is no research evaluating the efficacy of SDM compared to usual care (CAU), as it relates to quality of care and more specifically treatment adherence, in bipolar disorder (BD). METHODS/DESIGN: This is a 12-month multi-centre, cluster-randomized controlled trial comparing the efficacy of SDM to CAU. Adult BD patients (n = 300) will be eligible after stabilization for at least 4 weeks following an acute mood episode. The intervention will consist of applying the standardized SDM process as developed by the Ottawa Hospital Research Institute in order to choose the maintenance treatment of BD. A multidisciplinary team developed a decision aid "choose my long-term treatment with my doctor" for BD patients to clarify possible therapeutic options. Primary outcome will assess the patient's level of adherence (based on hetero-evaluation) of ongoing treatment at 12 months. Secondary outcomes will assess the difference between the 2 groups of patients in terms of adherence to maintenance drug therapy based on other measures (self-assessment scale and plasma levels of mood stabilizers). Additionally, other dimensions will be assessed: decisional conflict, satisfaction with care and involvement in decision making, beliefs about treatment, therapeutic relationship, knowledge about information for medical decision and clinical outcomes (depression, mania, functioning and quality of life). The primary endpoint will be analysed without adjustment by comparison of adherence scores between the two groups using Student t-tests or Mann-Whitney tests according to the variable distribution. A set of secondary analyses will be adjusted for covariates of clinical interest using generalized linear mixed regression models. DISCUSSION: This will be the first study evaluating the effect of an SDM intervention on patient adherence in BD. This is also an innovative protocol because it proposes the development of an evidence-based tool that should help patients and clinicians to initiate discussions regarding the use of BD treatment. TRIAL REGISTRATION: The study has been registered with ClinicalTrials.gov as NCT03245593 .

Effects of submaximal and supramaximal interval training on determinants of endurance performance in endurance athletes.

We compared the effects of submaximal and supramaximal cycling interval training on determinants of exercise performance in moderately endurance-trained men. Maximal oxygen consumption (VO2max ), peak power output (Ppeak ), and peak and mean anaerobic power were measured before and after 6 weeks (3 sessions/week) of submaximal (85% maximal aerobic power [MP], HIIT85 , n = 8) or supramaximal (115% MP, HIIT115 , n = 9) interval training to exhaustion in moderately endurance-trained men. High-intensity training volume was 47% lower in HIIT115 vs HIIT85 (304 ± 77 vs 571 ± 200 min; P < 0.01). Exercise training was generally associated with increased VO2max (HIIT85 : +3.3 ± 3.1 mL/kg/min; HIIT115 : +3.3 ± 3.6 ml/kg/min; Time effect P = 0.002; Group effect: P = 0.95), Ppeak (HIIT85 : +18 ± 9 W; HIIT115 : +16 ± 27 W; Time effect P = 0.045; Group effect: P = 0.49), and mean anaerobic power (HIIT85 : +0.42 ± 0.69 W/kg; HIIT115 : +0.55 ± 0.65 W/kg; Time effect P = 0.01; Group effect: P = 0.18). Six weeks of submaximal and supramaximal interval training performed to exhaustion seems to equally improve VO2max and anaerobic power in endurance-trained men, despite half the accumulated time spent at the target intensity.

A double amino-acid change in the HLA-A peptide-binding groove is associated with response to psychotropic treatment in patients with schizophrenia.

The choice of an efficient psychotropic treatment for patients with schizophrenia is a key issue to improve prognosis and quality of life and to decrease the related burden and costs. As for other complex disorders, response to drugs in schizophrenia is highly heterogeneous and the underlying molecular mechanisms of this diversity are still poorly understood. In a carefully followed-up cohort of schizophrenic patients prospectively treated with risperidone or olanzapine, we used a specially designed single-nucleotide polymorphism (SNP) array to perform a large-scale genomic analysis and identify genetic variants associated with response to psychotropic drugs. We found significant associations between response to treatment defined by the reduction in psychotic symptomatology 42 days after the beginning of treatment and SNPs located in the chromosome 6, which houses the human leukocyte antigen (HLA). After imputation of the conventional HLA class I and class II alleles, as well as the amino-acid variants, we observed a striking association between a better response to treatment and a double amino-acid variant at positions 62 and 66 of the peptide-binding groove of the HLA-A molecule. These results support the current notion that schizophrenia may have immune-inflammatory underpinnings and may contribute to pave the way for personalized treatments in schizophrenia.

Screening hypersexuality in Parkinson's disease in everyday practice.

OBJECTIVE: The purpose of this study was to develop a short and reliable measure of hypersexuality that could be used in everyday practice in patients with Parkinson's disease (PD). DESIGN: The original questionnaire containing twenty-five-items, the Sexual Addiction Screening Test (SAST), was shortened and tested in a PD population. METHODS: Successive reductions were performed until a final set of items satisfied the model fit requirements. The testing phase consisted of administering the SAST questionnaire to 159 PD patients. It included i) acceptability, ii) dimensionality construct validity, and iii) a complete general correlation structure of data. Finally, criterion validity of the final version of the instrument was assessed. RESULTS: The initial questionnaire was reduced to five items (PD-SAST) with a cut-off score of 2. Psychometric analysis revealed three factors corresponding to "Preoccupation", "Cannot stop" and "Relationship disturbance". The discriminant validity of the PD-SAST was high (ROC area under the curve: 0.96). CONCLUSIONS: The PD-SAST performs well as a screening instrument. It has been found to be acceptable to patients and is ready for use. Moreover, it tests multidimensional aspects of hypersexuality.

CAGE, RAPS4, RAPS4-QF and AUDIT screening tests for men and women admitted for acute alcohol intoxication to an emergency department: are standard thresholds appropriate?

AIMS: A number of screening instruments are routinely used in Emergency Department (ED) situations to identify alcohol-use disorders (AUD). We wished to study the psychometric features, particularly concerning optimal thresholds scores (TSs), of four assessment scales frequently used to screen for abuse and/or dependence, the cut-down annoyed guilty eye-opener (CAGE), Rapid Alcohol Problem Screen 4 (RAPS4), RAPS4-quantity-frequency and AUD Identification Test (AUDIT) questionnaires, particularly in the sub-group of people admitted for acute alcohol intoxication (AAI). METHODS: All included patients [AAI admitted to ED (blood alcohol level ≥0.8 g/l)] were assessed by the four scales, and with a gold standard (alcohol dependence/abuse section of the Mini International Neuropsychiatric Interview), to determine AUD status. To investigate the TSs of the scales, we used Youden's index, efficiency, receiver operating characteristic (ROC) curve techniques and quality ROC curve technique for optimized TS (indices of quality). RESULTS: A total of 164 persons (122 males, 42 females) were included in the study. Nineteen (11.60%) were identified as alcohol abusers alone and 128 (78.1%) as alcohol dependents (DSM-IV). Results suggest a statistically significant difference between men and women (P < 0.05) in performance of the screening tests RAPS4 (≥1) and CAGE (≥2) for detecting abuse. Also, in this population, we show an increase in TSs of RAPS4 (≥2) and CAGE (≥3) for detecting dependence compared with those typically accepted in non-intoxicated individuals. The AUDIT test demonstrates good performance for detecting alcohol abuse and/or alcohol-dependent patients (≥7 for women and ≥12 for men) and for distinguishing alcohol dependence (≥11 for women and ≥14 for men) from other conditions. CONCLUSION: Our study underscores for the first time the need to adapt, taking into account gender, the thresholds of tests typically used for detection of abuse and dependence in this population.

Factors involved in the level of functioning of patients with schizophrenia according to latent variable modeling.

PURPOSE: This study aimed at using latent variable modelling to explore the significantly contributing variables to functioning in schizophrenia patients. METHODS: The study cohort comprised 296 schizophrenia patients evaluated once for demographic characteristics, functioning (FROGS, SWN-K, QLS) and symptomatology (Positive and Negative Syndrome Scale [PANSS]). First exploratory multivariate analyses were conducted and then a model with functioning as a latent variable was proposed and tested with the data. RESULTS: Symptomatology as negative, cognitive and excitation factor are significant predictors of functioning assessed through FROGS (P<0.0001), SWN-K and QLS (P<0.001). The model was constructed with functioning defined as a latent variable, indicators are subscores on FROGS, SWN-K, QLS and exogenous variable included symptomatology, Duration of Untreated Psychosis (DUP) and educational level. CONCLUSION: Using the five clinical dimensions of the PANSS, (Positive, Negative, Cognitive, Anxiety/Depression and Excitation) the negative and cognitive dimensions are highly correlated via the latent variable to the three dimensions of functioning evaluated by the FROGS: "daily life", "social functioning" and "treatment" and the QLS subscores (interpersonnal, common object, instrumental role). Educationnal level is positively linked to functioning but not DUP. The model emphasizes the need for treatment strategies that have an effect on cognitive-factors, to improve functioning in schizophrenia.

[Pharmacological management of anxiety in patients suffering from schizophrenia]. / Prise en charge médicamenteuse de l'anxiété chez le patient souffrant de schizophrénie.

INTRODUCTION: Anxiety is a major and frequent symptom of schizophrenia, which is associated with an increased risk of relapse, impaired functioning, lower quality of life and increased incidence of suicide attempts. Despite its clinical relevance, anxiety in schizophrenia remains poorly understood. In the prodromic phase, anxiety indicates a progression towards psychotic decompensation. After a first episode, it is an indicator of relapse. LITERATURE FINDINGS: Two approaches have been used to investigate anxiety in schizophrenia: (i) categorical approach (comorbidity of schizophrenia and anxiety disorders) and (ii) dimensional approach (anxiety as a major symptom of the "dysphoric" dimension). Clinical categorical studies reported an increased frequency of comorbidity between schizophrenia and obsessive-compulsive disorder, panic disorder, social phobia, post-traumatic stress disorder, generalized anxiety disorder, agoraphobia, and specific phobia. The dimensional approach proposes that five different factors contribute to the structure of the Positive and Negative Syndrome Scale (PANSS), with anxiety as a major symptom of the "dysphoria" dimension. Concerning diagnosis, it is unclear whether psychotic and neurotic anxiety differs in nature or intensity. Nevertheless, both are frequently opposed. DISCUSSION: Psychotic anxiety is intense, profound and hermetic. In contrast to neurotic anxiety, it is associated with psychomotor disturbances, such as agitation and sideration. There is no specific tool to evaluate anxiety in schizophrenia. The dimensional approach usually runs an evaluation using items or factors extracted from the most widely-used scales, i.e. PANSS or Brief Psychiatric Rating Scale (BPRS) or from anxiety scales developed in non-schizophrenic populations, such as the Hamilton Anxiety Scale (HAMA). Recently, we developed a specific scale for hetero-evaluation (Échelle Anxiété Schizophrénie [EAS scale]). The EAS scale was recently validated and the study of its sensitivity is ongoing. THERAPEUTICAL ISSUES: Several studies have examined the effects of antipsychotics on the anxious/depressive cluster extracted from the PANSS, and some other studies have specifically evaluated the effect of antipsychotics on depressive symptoms using the Montgomery and Asberg Depression Rating Scale (MADRS) and Calgary Depression Scale for Schizophrenia (CDSS), but to our knowledge, no study has reported the effect of antipsychotics or other treatment on anxiety when using a schizophrenia-specific scale. There are no specific guideline treatments for anxiety in schizophrenia. Among phenothiazines, cyamemazine is frequently prescribed in France, because of its potent anxiolytic activity and good neurological tolerance. Some authors have suggested a specific treatment with benzodiazepines. However, benzodiazepines should be used with caution, due to undesirable actions such as dependence, rebound and potentiation of certain lateral effects.

Comparison of methods for teaching developmental milestones to pediatric residents.

BACKGROUND: Interactive media are effective tools in teaching and allow for self-directed study, which develops skills for life-long learning among health professionals. With this type of study, the learner can review material at his/her own pace and target areas that require emphasis. Pediatric residents require an accurate understanding of developmental milestones in children of various ages and their normal variations. The best representation of developmental milestones requires video recordings of children demonstrating appropriate skills. However, such recordings are not always available, so printed materials are most often used. In this realm, a computer-based interactive learning tool using animated cartoons gives flexibility for presentation using drawings. We compared pediatric residents' knowledge of developmental milestones in neonates to 5-year-olds before and after study with either an interactive DVD or paper-based materials. METHODS: A team of physicians and educational specialists in Texas Tech University Health Sciences Center produced an interactive DVD containing animated cartoons and questions. Residents were divided into an intervention group that used the DVD and a control group that used traditional paper-based materials. Each group's improvement [or increase] in knowledge was measured. RESULTS: Compared with the 17 residents in the control group, the 37 in the intervention group tended to acquire more knowledge about developmental milestones. The mean scores at T1, T2, and T3 doubled from the initial scores in the intervention group, while no difference was observed in the control group. CONCLUSION: An interactive educational DVD can be an effective supplement to improve residents' knowledge of developmental milestones.

Diagnostic criteria for apathy in clinical practice.

BACKGROUND: Apathy is an important and distressing behavioural symptom in Alzheimer's disease and in various neuropsychiatric disorders. Recently, diagnostic criteria for apathy have been proposed. OBJECTIVES: In groups of patients suffering from different neuropsychiatric diseases, (i) to estimate the prevalence of patients meeting the proposed diagnostic criteria; (ii) to estimate the concurrent validity of the criteria with the neuropsychiatric inventory (NPI) apathy item; (iii) to identify the most frequently met criteria or sub-criteria in each specific neuropsychiatric disease and (iv) to estimate the inter-observer reliability of the diagnostic criteria for apathy. METHODS: This cross-sectional, multicentric, observational study was performed on 306 patients. Each of the participating centres had to check the presence of apathy according to the diagnostic criteria for apathy in consecutive patients belonging to the following diagnoses list: Alzheimer disease (AD), mixed dementia, mild cognitive impairment (MCI), Parkinson's disease (PD), Schizophrenia (DSM-IV) and major depressive episode. In addition to the clinical interview, the assessment included the Mini Mental Score Examination (MMSE) and the NPI. At the end of the visit, clinicians were required to check the diagnostic criteria for apathy. RESULTS: Using the diagnostic criteria for apathy, the frequency of apathy was of 53% in the whole population, 55% in AD, 70% in mixed dementia, 43% in MCI, 27% in PD, 53% in schizophrenia and 94% in major depressive episode. In AD, mixed dementia, MCI and PD, the NPI apathy score was significantly higher for patient fulfilling the apathy criteria. Goal-directed cognitive activity (criteria B2-Cognition) was the most frequently observed domain followed by goal-directed behaviour (criteria B1-Behaviour) and emotion (criteria B3), respectively. Inter-rater reliability was high for the overall diagnostic (κ coefficient = 0.93; p = 0.0001) and for each criteria. CONCLUSION: This study is the first one to test the diagnostic criteria for apathy in clinical practice. Results make the diagnostic criteria useful for clinical practice and research.

[Aspiration and ingestion of dental instruments--diagnosis, treatment and prevention].

Aspiration and ingestion of foreign bodies of dental origin during treatment may cause a gastrointestinal and airway obstruction or perforation, and may constitute a life threatening situation. Ingestion occurs more often than aspiration and usually does not cause any clinical signs or symptoms. Most often it will spontaneously rejected from the gastrointestinal tract by peristaltic movement without any coimplication. However aspiration always requires treatment since foreign bodies there may cause inflammatory reaction and even severe obstruction and death. This article describes one case of aspiration and 3 cases of ingestion of dental instruments and materials. We discuss the diagnostic procedure: evidence of clinical signs and plain radiography, CT and the use of contrast material in case of radiolucent foreign bodies. The modern technique of endoscopy is successfully performed for diagnosis and treatment of foreign bodies in case of aspiration with minimal complications. We suggest a step by step protocol of treatment at the dental clinic in the case of ingestion/aspiration of foreign body and discuss several prevention techniques.

[Pre-septal orbital cellulitis from odentogenic origin--combined surgical and endodontic approach: a case report].

Orbital abscesses are common infectious diseases. The etiology of orbital abscesses may vary from common sinusitis in most of the cases, to cocaine sniffing. As a result of the proximity to the brain, orbital abscesses may complicate to life threatening situations. The infectious process spreads to the orbit in several ways: hematogenous, via anatomic spaces in the maxillofacial region, direct invasion. The treatment philosophy combines surgical and Antibiotic therapy to resolve the acute phase of the disease, followed by elimination of the source. The purpose of this paper is to report a case of pre septal orbital cellulitis, that was treated surgically combined with endodontic therapy. To describe the different subtypes of orbital abscesses, differential diagnosis, imaging and treatment options.

Fluoride ion toxicity in rabbit kidney thick ascending limb cells.

BACKGROUND AND OBJECTIVE: Some halogenated agents, especially methoxyflurane, because of a higher level of fluoride production, induce a renal concentrating defect that could be related to an ascending limb impairment. We investigated the mechanisms of fluoride toxicity on an immortalized cell line. METHODS: Cells were cultured for 2, 6 or 24 h in the presence of fluoride. Toxicity evaluation was based on: cell numbers, protein content, leucine-incorporation, lactate dehydrogenase (LDH) and N-acetyl-beta-glucosaminidase (NAG) releases, Na-K-ATPase and Na-K-2Cl activities, electron microscope studies. Infrared analysis and fluoride microdetermination allowed crystal components. RESULTS: At 5 mmol after 24 h, fluoride decreased cell numbers (-14%, *P < 0.05), protein content (-16%*), leucine incorporation (-54%*), Na-K-2Cl activity (-84%*), increased LDH (+145%*) and NAG release (+190%*). Na-K-ATPase was more sensitive and impaired from 1 mmol for 24h and after 2 h at 5 mmol. Crystal formation in mitochondria occurred after 6 h at 5 mmol. Infra-red analysis and fluoride microdetermination established that crystals contained sodium, phosphate and fluoride. CONCLUSIONS: The results suggest that the Na-K-ATPase pump is a major target for fluoride toxicity in Henle's loop.

Study of atrial arrhythmias in a computer model based on magnetic resonance images of human atria.

The maintenance of multiple wavelets appears to be a consistent feature of atrial fibrillation (AF). In this paper, we investigate possible mechanisms of initiation and perpetuation of multiple wavelets in a computer model of AF. We developed a simplified model of human atria that uses an ionic-based membrane model and whose geometry is derived from a segmented magnetic resonance imaging data set. The three-dimensional surface has a realistic size and includes obstacles corresponding to the location of major vessels and valves, but it does not take into account anisotropy. The main advantage of this approach is its ability to simulate long duration arrhythmias (up to 40 s). Clinically relevant initiation protocols, such as single-site burst pacing, were used. The dynamics of simulated AF were investigated in models with different action potential durations and restitution properties, controlled by the conductance of the slow inward current in a modified Luo-Rudy model. The simulation studies show that (1) single-site burst pacing protocol can be used to induce wave breaks even in tissue with uniform membrane properties, (2) the restitution-based wave breaks in an atrial model with realistic size and conduction velocities are transient, and (3) a significant reduction in action potential duration (even with apparently flat restitution) increases the duration of AF. (c) 2002 American Institute of Physics.

A computer model of human atria with reasonable computation load and realistic anatomical properties.

Atrial fibrillation is the most frequent arrhythmia, provoking discomfort, heart failure and arterial embolisms. The aim of this work is to develop a simplified anatomical computer model of human atria for the study of atrial arrhythmias and the understanding of electrical propagation mechanisms. With the model we propose, up to 40 s of real-time propagation have been simulated on a single-processor computer. The size and the electrophysiological properties of the simulated atria are within realistic values and information about anatomy has been taken into account in a three-dimensional structure. Besides normal sinus beat, pathological phenomena such as flutter and fibrillation have been induced using a programmed stimulation protocol. One important observation in our model is that atrial arrhythmias are a combination of functional and anatomical reentries and that the geometry plays an important role. This virtual atrium can reproduce electrophysiological observations made in humans but with the advantage of showing in great detail how arrhythmias are initiated and sustained. Such details are difficult or impossible to study in humans. This model will serve us as a tool to evaluate the impact of new therapeutic strategies and to improve them.