See, feel, act: Hierarchical learning for complex manipulation skills with multisensory fusion.

Humans are able to seamlessly integrate tactile and visual stimuli with their intuitions to explore and execute complex manipulation skills. They not only see but also feel their actions. Most current robotic learning methodologies exploit recent progress in computer vision and deep learning to acquire data-hungry pixel-to-action policies. These methodologies do not exploit intuitive latent structure in physics or tactile signatures. Tactile reasoning is omnipresent in the animal kingdom, yet it is underdeveloped in robotic manipulation. Tactile stimuli are only acquired through invasive interaction, and interpretation of the data stream together with visual stimuli is challenging. Here, we propose a methodology to emulate hierarchical reasoning and multisensory fusion in a robot that learns to play Jenga, a complex game that requires physical interaction to be played effectively. The game mechanics were formulated as a generative process using a temporal hierarchical Bayesian model, with representations for both behavioral archetypes and noisy block states. This model captured descriptive latent structures, and the robot learned probabilistic models of these relationships in force and visual domains through a short exploration phase. Once learned, the robot used this representation to infer block behavior patterns and states as it played the game. Using its inferred beliefs, the robot adjusted its behavior with respect to both its current actions and its game strategy, similar to the way humans play the game. We evaluated the performance of the approach against three standard baselines and show its fidelity on a real-world implementation of the game.

[Childhood steroid-dependent idiopathic nephrotic syndrome: Predictive factors for the need of immunosuppressive treatment]. / Syndrome néphrotique idiopathique corticodépendant de l'enfant : facteurs prédictifs de recours à un traitement immunosuppresseur.

BACKGROUND AND AIMS: More than half of the children with idiopathic nephrotic syndrome become steroid-dependent (or frequent relapsers) and will later require the use of complementary treatment aiming to reduce steroids' side effects and to limit the number of proteinuria relapses. It appears important to identify these children as early as possible in order to adapt their treatment. The aim of this study was to analyze the population of children, under 18 years of age, diagnosed between 1/01/2000 and 31/05/2015 with an idiopathic nephrotic syndrome and followed at the Montpellier University Hospital to search for criteria predictive of steroid-sparing agent use. METHODS: In this retrospective study of children with idiopathic nephrotic syndrome, the exclusion criteria were primary steroid resistance and children with no proteinuria relapse after diagnosis. RESULTS: Eighty-four children (54 boys) were included in this study. The mean follow-up duration was 5.5 years (0.75-16). The mean age at diagnosis was 4.6 years. Sixty-five children (77%) received at least one steroid-sparing agent during their follow-up, within a mean 10 months after diagnosis. In these patients, the first relapse of the disease occurred earlier when compared with the children who were maintained on steroid alone (4 months vs 7 months; P<0.001). The use of methylprednisolone pulses to obtain a remission, the cumulative dose of steroid treatment, and the number of proteinuria relapses were also significantly correlated with the use of complementary immunosuppressive therapy. CONCLUSION: We found no predictive criteria of the use of steroid-sparing agents at diagnosis in our population of children. Nevertheless, with the steroid regimen used, the time within which the first proteinuria relapse occurred appears to be a significant criterion for the secondary use of a steroid-sparing agent. These data should be taken into account when choosing the treatment regimen.

Nephrogenic syndrome of inappropriate antidiuresis.

Mutations in the vasopressin V2 receptor gene are responsible for two human tubular disorders: X-linked congenital nephrogenic diabetes insipidus, due to a loss of function of the mutant V2 receptor, and the nephrogenic syndrome of inappropriate antidiuresis, due to a constitutive activation of the mutant V2 receptor. This latter recently described disease may be diagnosed from infancy to adulthood, as some carriers remain asymptomatic for many years. Symptomatic children, however, typically present with clinical and biological features suggesting inappropriate antidiuretic hormone secretion with severe hyponatremia and high urine osmolality, but a low plasma arginine vasopressin level. To date, only two missense mutations in the vasopressin V2 receptor gene have been found in the reported patients. The pathophysiology of the disease requires fuller elucidation as the phenotypic variability observed in patients bearing the same mutations remains unexplained. The treatment is mainly preventive with fluid restriction, but urea may also be proposed.

[Hemolytic uremic syndrome with severe neurological involvement: how should it be managed?]. / Syndrome hémolytique et urémique avec atteinte neurologique sévère: quelle prise en charge?

INTRODUCTION: The management of diarrhea-associated hemolytic and uremic syndrome (D(+) HUS) with severe acute neurological involvement continues to be debated. We report on 2 cases and discuss the treatment. CASE REPORT 1: A 2.5-year-old girl presented with generalized seizures during gastroenteritis. Blood tests revealed features of HUS and a pyramidal syndrome was found on physical examination. Brain MRI, 24h after admission, showed lesions in the periventricular and subcortical area. She was started on peritoneal dialysis (PD) and daily plasma exchanges (PE) for 10 days. Her neurological condition improved quickly as well as the findings of the second brain MRI performed after PE. One year later she had no apparent neurological or renal sequelae. CASE REPORT 2: A 2.5-year-old boy presented with generalized seizures during gastroenteritis for 3 days, leading to a diagnosis of HUS. He also had a severe pyramidal syndrome with spastic tetraparesis and aphasia. Brain MRI, 48 h after admission, revealed severe bilateral and symmetric lesions involving the thalami, internal and external capsules, lenticular nuclei, and brainstem. He was started on PD and daily PE for 10 days. Brain MRI performed after PE was unchanged. Clinically, his neurological condition improved slowly with regression of spastic tetraparesis and progressive recovery of motor skills. Nine months later, his renal function is normal but he is still having intensive physiotherapy. DISCUSSION: Both children have received similar management including 10 PEs started within 48 h after the diagnosis of D(+) HUS with severe neurological involvement, but their neurological outcome appeared to be significantly different. There is no clear proof in the literature concerning the effects of PE in such patients, even when performed very early. Eculizumab, an antibody that inhibits complement factor 5a and the formation of the membrane attack complex, has recently been used in such cases and seems to provide a more specific therapeutic action. Control studies are needed to specify its use in this disease.

Secret agents: inferences about hidden causes by 10- and 12-month-old infants.

Considerable evidence indicates that preverbal infants expect that only physical contact can cause an inanimate object to move. However, very few studies have investigated infants' expectations about the source of causal power. In three experiments, we found that (a) 10- and 12-month-old infants expect a human hand, and not an inanimate object, to be the primary cause of an inanimate object's motion; (b) infants' expectations can lead them to infer a hidden causal agent without any direct perceptual evidence; and (c) infants do not infer a hidden causal agent if the moving object was previously shown to be capable of self-generated motion.

[BK virus infection in a child after an hematopoietic stem cell transplantation]. / Infection à BK Virus après allogreffe de cellules hématopoïétiques. A propos d'un cas.

Polyomavirus hominis 1, better known as BK virus (BKV), infects up to 90% of the general population. Significant clinical manifestations can be seen in immunocompromised patients. We report a case of haemorragic cystitis likely due to BKV in a child after allotransplantation of hematopoietic stem cells. A 10-year old boy with poor-prognosis acute T lymphoblastic leukaemia underwent cord blood allogeneic stem cell transplantation while in his first relapse. Macroscopic haematuria and low back pain occurred by day 95, in the context of acute graft versus host disease and pulmonary aspergillosis. Histopathologic examination showed a cytopathogenetic effect consistent with the diagnosis of BKV infection. Urinary PCR was positive for BKV. Treatment with cidofovir was followed by a marked improvement of urinary symptoms. The current understanding, diagnosis, and treatment of BKV-associated infection is discussed.

Error patterns of 3rd-year medical students on the cardiovascular physical examination.

BACKGROUND: Recent research documents widespread deficits in the physical examination skills of practicing physicians. PURPOSE: This study explored physical examination skills of 3rd-year medical students after completion of a course in physical diagnosis. METHODS: Standardized patient physical examination checklist data were analyzed for a cohort of 2,038 medical students for a patient presenting with classic signs and symptoms of an acute myocardial infarction. A follow-up paper case and survey explored reasons underlying omissions. RESULTS: Students systematically omitted 3 of 10 component maneuvers critical to the evaluation of a patient with shortness of breath and chest pain. The same pattern of omissions was observed across 8 medical schools and over 2 successive years. The paper case follow-up study ruled out time constraints and performance anxiety as the cause. Survey data revealed that students may omit a maneuver due to inability to recall pertinence (blood pressure in both arms) or difficulty discriminating findings (heart sounds at different locations), or because of inadequate technical mastery (percussion of the lungs). CONCLUSIONS: These data suggest fundamental inadequacies in the current paradigm for teaching physical examination skills. Standardized patient checklist data can provide an informative window into the efficacy of teaching practices.

Generalization, similarity, and Bayesian inference.

Shepard has argued that a universal law should govern generalization across different domains of perception and cognition, as well as across organisms from different species or even different planets. Starting with some basic assumptions about natural kinds, he derived an exponential decay function as the form of the universal generalization gradient, which accords strikingly well with a wide range of empirical data. However, his original formulation applied only to the ideal case of generalization from a single encountered stimulus to a single novel stimulus, and for stimuli that can be represented as points in a continuous metric psychological space. Here we recast Shepard's theory in a more general Bayesian framework and show how this naturally extends his approach to the more realistic situation of generalizing from multiple consequential stimuli with arbitrary representational structure. Our framework also subsumes a version of Tversky's set-theoretic model of similarity, which is conventionally thought of as the primary alternative to Shepard's continuous metric space model of similarity and generalization. This unification allows us not only to draw deep parallels between the set-theoretic and spatial approaches, but also to significantly advance the explanatory power of set-theoretic models.

A global geometric framework for nonlinear dimensionality reduction.

Scientists working with large volumes of high-dimensional data, such as global climate patterns, stellar spectra, or human gene distributions, regularly confront the problem of dimensionality reduction: finding meaningful low-dimensional structures hidden in their high-dimensional observations. The human brain confronts the same problem in everyday perception, extracting from its high-dimensional sensory inputs-30,000 auditory nerve fibers or 10(6) optic nerve fibers-a manageably small number of perceptually relevant features. Here we describe an approach to solving dimensionality reduction problems that uses easily measured local metric information to learn the underlying global geometry of a data set. Unlike classical techniques such as principal component analysis (PCA) and multidimensional scaling (MDS), our approach is capable of discovering the nonlinear degrees of freedom that underlie complex natural observations, such as human handwriting or images of a face under different viewing conditions. In contrast to previous algorithms for nonlinear dimensionality reduction, ours efficiently computes a globally optimal solution, and, for an important class of data manifolds, is guaranteed to converge asymptotically to the true structure.

Separating style and content with bilinear models.

Perceptual systems routinely separate "content" from "style," classifying familiar words spoken in an unfamiliar accent, identifying a font or handwriting style across letters, or recognizing a familiar face or object seen under unfamiliar viewing conditions. Yet a general and tractable computational model of this ability to untangle the underlying factors of perceptual observations remains elusive (Hofstadter, 1985). Existing factor models (Mardia, Kent, & Bibby, 1979; Hinton & Zemel, 1994; Ghahramani, 1995; Bell & Sejnowski, 1995; Hinton, Dayan, Frey, & Neal, 1995; Dayan, Hinton, Neal, & Zemel, 1995; Hinton & Ghahramani, 1997) are either insufficiently rich to capture the complex interactions of perceptually meaningful factors such as phoneme and speaker accent or letter and font, or do not allow efficient learning algorithms. We present a general framework for learning to solve two-factor tasks using bilinear models, which provide sufficiently expressive representations of factor interactions but can nonetheless be fit to data using efficient algorithms based on the singular value decomposition and expectation-maximization. We report promising results on three different tasks in three different perceptual domains: spoken vowel classification with a benchmark multi-speaker database, extrapolation of fonts to unseen letters, and translation of faces to novel illuminants.

The epidemiology of nonsteroidal anti-inflammatory drugs.

Nonsteroidal anti-inflammatory drug (NSAID) use has increased dramatically in the past two decades. A large proportion of the elderly population (more than 65 years of age) holds a current or recent NSAID prescription, accounting for approximately 90% of all NSAID prescriptions. Despite studies that advise finding alternatives for NSAIDs for the management of osteoarthritis, physicians often prescribe NSAIDs first for such common musculoskeletal conditions. Despite being identified as risk factors for gastrointestinal complications, the simultaneous use of two NSAIDs and the coadministration of NSAIDs with corticosteroids and with coumadin continue to occur. The point prevalence of NSAID-induced ulcers is 10% to 30%, and 15% to 35% of all peptic ulcer complications are caused by NSAIDs. The increased risk of gastrointestinal complications when NSAIDs are used is 3% to 5%. This risk increases with other identified risk factors (eg, older age, previous gastrointestinal history, comorbid diseases and poor health). Gastrointestinal causes of hospitalization (eg, gastrointestinal hemorrhage and perforation) and death have increased in parallel to increased NSAID use. 'Antiulcer' agents are prescribed twice as often in NSAID users, and the economic impact (eg, diagnostic tests and hospitalization) is that about one-third of the arthritis budget has been dedicated to deal with gastrointestinal side effects of NSAIDs. Misoprostol and omeprazole have been shown to be cytoprotective for the gastroduodenal mucosa when NSAIDs are used, and misoprostol has been shown to reduce the risk of gastroduodenal ulcer complications. Economic evaluations have suggested that these agents are a cost effective means of dealing with such NSAID-associated problems. Although no NSAID is totally safe, a number of studies have demonstrated that NSAIDs may be ranked according to relative gastrointestinal toxicity. The role of Helicobacter pylori in NSAID-associated problems remains uncertain.

Temporal arteritis: a review and case history.

Temporal cell arteritis is a systemic vasculitis occurring mainly in the elderly. Classic symptoms such as headache, jaw claudication, visual changes, and polymyalgia rheumatica make the diagnosis relatively easy. Occult or asymptomatic presentations, however, are often missed or attributed to another cause. It is important for clinicians to be aware of the diverse presentations of this disease to avoid unnecessary investigations and prevent complications such as visual loss, myocardial ischemia, cerebrovascular accident, and death. This report presents the case of a patient who was referred with anemia and an elevated erythrocyte sedimentation rate, and who developed a headache during the hospital admission.

Compensation to a department of medicine and its faculty members for the teaching of medical students and house staff.

BACKGROUND: Changes in the organization and financing of health care threaten to alter the prevailing system of financing the teaching of medical students and residents. Little information is available from private medical schools and teaching hospitals about the extent of teaching by faculty members or the mechanisms and levels of reimbursement for teaching. METHODS: We surveyed faculty members in the Department of Medicine at Columbia-Presbyterian Medical Center to ascertain the extent of their teaching activities. A standard number of hours was assigned to each activity, and the total number of teaching hours was calculated for each faculty member. Teaching of fellows and in continuing medical education programs was excluded. We also determined how much money the Department of Medicine received in payment for faculty members' teaching activities, and the sources of this compensation. RESULTS: In the 1992-1993 academic year, the 188 full-time faculty members spent a total of 46,086 hours teaching (mean [+/- SD], 245 +/- 178 hours per faculty member); 10,780 hours (23.4 percent) were spent teaching medical students, and 35,306 hours (76.6 percent) teaching house staff. Eighty percent of faculty members taught for 137 or more hours each. In a multivariate analysis including faculty rank, subspecialty division, years since graduation from medical school, sex, and tenure or clinical track, senior faculty members (P = 0.02), members of certain subspecialty divisions (P < 0.001), and women (P = 0.05) contributed more than the average number of teaching hours. An additional 56 non-full-time faculty members contributed a total of 5684 hours. The net reimbursement to the department for teaching totaled $965,808, or about $16 per hour of teaching by full-time faculty members, after the cost of fringe benefits was excluded. CONCLUSIONS: Faculty members of the department of medicine at a major medical center contribute a large number of hours teaching medical students and house staff. This effort is poorly compensated. Cost-containment efforts have the potential to jeopardize fragile social contracts at academic health centers whereby the faculty participates in teaching by contributing unreimbursed or underreimbursed time.

Accelerated nodulosis in a patient with psoriasis and arthritis during treatment with methotrexate.

A 66-year-old woman with longstanding psoriasis involving the skin presented with asymmetrical polyarthritis. Methotrexate (MTX) was given initially intramuscularly and orally. Intramuscular MTX was discontinued, and a few months after she had been taking only oral MTX she developed nodules, first in surgical incisions, and subsequently in her buttocks, thighs, legs, and arms. Reduction of the dose of oral MTX was followed by gradual diminution in size of the nodules and then total disappearance.

Peripheral pulmonary artery stenosis in pregnancy. A report of two cases.

Peripheral pulmonary artery stenosis is a rare congenital anomaly often associated with the maternal rubella syndrome. Two patients with the disorder underwent four successful pregnancies.

Malar rash in a patient with Reiter's syndrome--a clue for the diagnosis of human immunodeficiency virus infection.

We describe a man who presented with Reiter's syndrome and a new prominent malar rash. The malar rash was the clue for the early diagnosis of human immunodeficiency virus (HIV) infection in this patient. A high index of suspicion for the diagnosis of HIV infection is required in patients with Reiter's syndrome presenting with unusual clinical manifestations.

Septic bursitis in human immunodeficiency virus infection.

Septic bursitis is a well described entity in immunocompromised patients. Common factors contributing to an immunocompromised state are alcoholism and corticosteroid therapy. We describe 2 patients with Staphylococcus aureus olecranon bursitis with evidence of human immunodeficiency virus (HIV) infection and no other contributing factors to immunodeficiency. The clinical course in these patients was refractory to conservative management. Such a persistent course of septic bursitis, especially in the absence of other contributing factors, should raise the possibility of HIV infection.

Non-steroidal anti-inflammatory drugs (NSAIDs) cause gastrointestinal intolerance and major bleeding--or do they?

Non-steroidal anti-inflammatory drugs are a mainstay of treatment of the inflammatory arthritides. Unfortunately, they are often associated with dyspepsia, and this troublesome side-effect is a limitation to their chronic use by many patients. The use of enteric-coated preparations has improved the ability of this large group of patients to use these drugs. The appearance of suppository preparations has further improved tolerability of these medications. Though dyspepsia is a common adverse effect, there is little correlation between this side-effect and the prevalence of relevant gastrointestinal bleeding in practice. The latter is an uncommon event, but is of particular concern in the elderly. The introduction of concomitant use of a number of gastroenterologic medications has improved the rheumatologist's ability to give non-steroidal anti-inflammatory drugs to these patients. Despite this, no combination has been proven to be absolutely safe. Cytoprotection by a number of gastroenterologic preparations offers a means of avoiding, or decreasing, troublesome gastritis, and reducing the risk of relevant bleeding. Non-steroidal anti-inflammatory drugs must be used in this (elderly) population with caution, and prospective studies are needed to confirm the role of potential cytoprotective therapy in clinical practice.