Context matters during pick-and-place in VR: Impact on search and transport phases.

When considering external assistive systems for people with motor impairments, gaze has been shown to be a powerful tool as it is anticipatory to motor actions and is promising for understanding intentions of an individual even before the action. Up until now, the vast majority of studies investigating the coordinated eye and hand movement in a grasping task focused on single objects manipulation without placing them in a meaningful scene. Very little is known about the impact of the scene context on how we manipulate objects in an interactive task. In the present study, it was investigated how the scene context affects human object manipulation in a pick-and-place task in a realistic scenario implemented in VR. During the experiment, participants were instructed to find the target object in a room, pick it up, and transport it to a predefined final location. Thereafter, the impact of the scene context on different stages of the task was examined using head and hand movement, as well as eye tracking. As the main result, the scene context had a significant effect on the search and transport phases, but not on the reach phase of the task. The present work provides insights into the development of potential supporting intention predicting systems, revealing the dynamics of the pick-and-place task behavior once it is realized in a realistic context-rich scenario.

Associations between Psychological Variables, Knowledge, Attitudes, Risk Perceptions and Health Behaviours towards COVID-19 among Adolescents.

There is currently little scientific evidence available that allows us to understand patterns of knowledge, risk perception, attitudes, and behaviours among adolescents in relation to COVID-19. This study aims to analyse the relationship between knowledge about COVID-19, risk perception, and psychological variables and the adherence to preventive measures among the adolescent population. It is a descriptive cross-sectional study, which included adolescents between the ages of 12 and 18 (n = 354). The questionnaire was sent to several secondary schools chosen by convenience sampling and following a non-probabilistic snowball sampling. Descriptive, univariate, and multivariate analyses were carried out in order to determine whether knowledge about COVID-19, risk perception, tolerance of frustration, planning and decision-making, family functionality, self-efficacy, self-esteem, and social skills are related to preventive measures. The adoption among adolescents of behaviours which protect them against COVID-19 depends on knowledge about the disease, the perception of the risk it poses to them, as well as their tolerance of frustration and planning and decision-making abilities. The relationship between the individual variables among adolescents with the adoption of behaviours which protect them against COVID-19 has been confirmed. The development of intervention and communication strategies that take the psychosocial situation of adolescents into account will help to increase the adoption of protective health behaviours in the context of a pandemic.

Evaluation of a liquid membrane-based tunable lens and a solid-state LIDAR camera feedback system for presbyopia.

Presbyopia is an age-related loss of accommodation ability of the eye which affects individuals in their late 40s or early 50s. Presbyopia reduces the ability of a person to focus on closer objects at will. In this study, we assessed electronically tunable lenses for their aberration properties as well as for their use as correction lenses. The tunable lenses were evaluated in healthy subjects with cycloplegia by measuring visual acuity and contrast sensitivity for their use in presbyopia correction. Furthermore, we have developed and demonstrated the feasibility of a feedback mechanism for the operation of tunable lenses using a portable solid-state LIDAR camera with a processing time of 40 ± 5 ms.

The Impact of Shape-Based Cue Discriminability on Attentional Performance.

With rapidly developing technology, visual cues became a powerful tool for deliberate guiding of attention and affecting human performance. Using cues to manipulate attention introduces a trade-off between increased performance in cued, and decreased in not cued, locations. For higher efficacy of visual cues designed to purposely direct user's attention, it is important to know how manipulation of cue properties affects attention. In this verification study, we addressed how varying cue complexity impacts the allocation of spatial endogenous covert attention in space and time. To gradually vary cue complexity, the discriminability of the cue was systematically modulated using a shape-based design. Performance was compared in attended and unattended locations in an orientation-discrimination task. We evaluated additional temporal costs due to processing of a more complex cue by comparing performance at two different inter-stimulus intervals. From preliminary data, attention scaled with cue discriminability, even for supra-threshold cue discriminability. Furthermore, individual cue processing times partly impacted performance for the most complex, but not simpler cues. We conclude that, first, cue complexity expressed by discriminability modulates endogenous covert attention at supra-threshold cue discriminability levels, with increasing benefits and decreasing costs; second, it is important to consider the temporal processing costs of complex visual cues.

SARS-COV-2 infection in pregnant women and newborns in a Spanish cohort (GESNEO-COVID) during the first wave.

BACKGROUND: Knowledge about SARS-CoV-2 infection in pregnancy and newborns is scarce. The objective of this study is to analyse clinical and epidemiological characteristics of a cohort of women infected with SARS-CoV-2 during pregnancy and their newborns exposed to SARS-CoV-2 during gestation. METHODS: Multicentric observational study of Spanish hospitals from the GESNEO-COVD cohort, participants in RECLIP (Spanish Network of Paediatric Clinical Assays). Women with confirmed SARS-CoV-2 infection by PCR and/or serology during pregnancy, diagnosed and delivering during the period 15/03/2020-31/07/2020 were included. Epidemiological, clinical, and analytical data was collected. RESULTS: A total of 105 pregnant women with a median of 34.1 years old (IQR: 28.8-37.1) and 107 newborns were included. Globally, almost 65% of pregnant women had some COVID-19 symptoms and more than 43% were treated for SARS-COV-2. Overall, 30.8% of pregnant women had pneumonia and 5 (4.8%) women were admitted to the intensive care unit needing invasive mechanical ventilation. There was a rate of 36.2% of caesarean sections, which was associated with pneumonia during pregnancy (OR: 4.203, CI 95%: 1.473-11.995) and lower gestational age at delivery (OR: 0.724, CI 95%: 0.578-0.906). The prevalence of preterm birth was 20.6% and prematurity was associated with pneumonia during gestation (OR: 6.970, CI95%: 2.340-22.750) and having a positive SARS-CoV-2 PCR at delivery (OR: 6.520, CI95%: 1.840-31.790). All nasopharyngeal PCR in newborns were negative at birth and one positivized at 15 days of life. Two newborns died, one due to causes related to prematurity and another of unexpected sudden death during early skin-to-skin contact after delivery. CONCLUSIONS: Although vertical transmission has not been reported in this cohort, the prognosis of newborns could be worsened by SARS-CoV-2 infection during pregnancy as COVID-19 pneumonia increased the risk of caesarean section deliveries and preterm births.

Saliency-Aware Subtle Augmentation Improves Human Visual Search Performance in VR.

Visual search becomes challenging when the time to find the target is limited. Here we focus on how performance in visual search can be improved via a subtle saliency-aware modulation of the scene. Specifically, we investigate whether blurring salient regions of the scene can improve participant's ability to find the target faster when the target is located in non-salient areas. A set of real-world omnidirectional images were displayed in virtual reality with a search target overlaid on the visual scene at a pseudorandom location. Participants performed a visual search task in three conditions defined by blur strength, where the task was to find the target as fast as possible. The mean search time, and the proportion of trials where participants failed to find the target, were compared across different conditions. Furthermore, the number and duration of fixations were evaluated. A significant effect of blur on behavioral and fixation metrics was found using linear mixed models. This study shows that it is possible to improve the performance by a saliency-aware subtle scene modulation in a challenging realistic visual search scenario. The current work provides an insight into potential visual augmentation designs aiming to improve user's performance in everyday visual search tasks.

Knowledge, Attitudes, Risk Perceptions, and Practices of Spanish Adolescents Toward the COVID-19 Pandemic: Validation and Results of the Spanish Version of the Questionnaire.

Background: Adolescence is a period with physical, psychological, biological, intellectual, and social changes in which there is usually little perception of risk. COVID-19 has generated constant situations of change and uncertainty worldwide. During the pandemic, the acquisition of preventive behaviors has been relevant. Various studies carried out with adults associate risk perception and the implementation of preventive behaviors with knowledge about the COVID-19 and with age, but there are not many studies with adolescents. Therefore, the objective is to validate, in Spanish, the questionnaire of the knowledge, attitudes, risk perceptions, and practices of adolescents toward the pandemic, and analyze it according to sociodemographic characteristics. Method: This study was a descriptive cross-sectional study, which included adolescents between the ages of 12-18 (n = 354). First, a translation and a back-translation of the questionnaire were performed. The questionnaire was presented in several high schools chosen by convenience sampling and following a non-probabilistic snowball sampling. Reliability and validity analyses were then carried out and the relationships between the different sociodemographic variables (gender, place of residence, level of education, if the person was in a sentimental relationship, and financial aid) were analyzed. Results: The reliability of the questionnaire is acceptable (ordinal alpha = 77%). Knowledge was higher in women, and in those with a higher level of education; and were lower in those who lived in smaller towns, as well as in those who had a member of their family receiving financial aid. In terms of attitudes and risk perceptions, younger adolescents had higher scores, and those who had a member of their family receiving financial aid, lower. Conclusion: The questionnaire is a reliable tool in the Spanish adolescent population. Knowledge was influenced by gender, place of residence, level of education, and financial aid. Attitudes and risk perceptions were influenced by age and financial aid. For practices, no predictors were found. In general, adolescents scored lower on knowledge about COVID-19, but they scored higher on COVID-19 safety practices.

Correlation between diagnosis of depression and symptoms present in primary care patients.

Depression is a chronic disease with a high prevalence that normally is episodic and an average episodic duration of 16 weeks. No analyses that evaluate the correlation between the evolution of the episode and its appearance have been found. The aim of this study is to analyze the correlation between symptomatic progression (appearance, maintenance, remission of different symptoms) and the evolution of the diagnosis of depression (onset, maintenance, and remission) in a cohort of patients diagnosed with and without major depression. A prospective cohort study was performed with a one year follow-up in which a random sample of 741 subjects attending primary care was interviewed. Diagnosis of depression was made according to DSM-IV criteria and symptoms presented were analyzed. These subjects were reevaluated at 6 months and 12 months. Depressed mood state, decreased interest or anhedonia and symptoms related to sleep (insomnia or hypersomnia), agitation, feeling of guilt, fatigue or energy loss, are consistent with the diagnosis. The rest of the symptoms display an evolution independent of the diagnostic trends. In Primary Care, it is important to know which are the key symptoms in the evolution of the diagnosis in order to achieve full remission of depression and avoid maintenance of residual symptoms that can become prodromal.

Bilateral Leydig cell tumour of the ovary: a rare cause of virilization in postmenopausal patient.

BACKGROUND: Leydig cell tumours of the ovary are very rare benign neoplasms, frequently associated with symptoms of virilisation, in postmenopausal patients. Only four cases of bilateral Leydig tumours have been reported in the literature. CASE REPORT: We report an additional case of bilateral presentation. A 77-year-old postmenopausal patient was referred from the Endocrinology Service due to a biochemical diagnosis of hyperandrogenism during hospital admission with unbalanced diabetes mellitus. The patient had suffered from alopecia and hirsutism for many years. Biological data confirmed an increment of androgen production. Ultrasonography showed a well-defined hyperechoic lesion of 12 mm in the right ovary. A CT scan demonstrated adrenal glands and ovaries without tumour. Bilateral adnexectomy by laparoscopy was carried out. RESULT: The pathological finding was a bilateral Leydig cell tumour, measuring 15 mm in the right ovary and 3 mm in the left ovary. Following treatment the patient experienced regression of the hirsutism and the plasma testosterone dropped to a normal level. CONCLUSION: In spite of its low incidence, it is a possibility that must be considered in all postmenopausal women with hyperandrogenism, and bilateral adnexectomy by laparoscopy is recommended as a diagnostic test and definitive treatment.

[Dobutamine stress echocardiography and troponin T as a marker of myocardial injury]. / Ecocardiografía de estrés con dobutamina y troponina T como marcador de daño miocárdico.

Introduction and objectives. Troponin T (TnT) is a very specific marker of myocardial damage. Our objective was to describe TnT behavior after dobutamine stress echocardiography (EDOB) and evaluate its usefulness for improving the diagnostic power of EDOB.Methods. Blood levels of TnT were measured at baseline and 3, 6, 12, and 24 h after EDOB in 63 patients (mean age: 69 9; 38 males). Coronary angiography was performed on 36 patients.Results. EDOB was positive in 29 patients and there was an increase over baseline values in 15 of them (51%); EDOB was negative in 34 patients and there was only a rise in TnT in 7 (20%; p < 0.01). The TnT increment was higher in patients with a positive response to EDOB (0.033 0.02 vs. 0.026 0.01; p < 0.01). The ischemia score index was higher in patients in which a significant increase in TnT values was later detected (0.41 0.31 vs. 0.38 0.20; p < 0.01). Coronariography was performed in 36 patients. EDOB was positive in 22 of the 29 patients with coronary artery disease (76%) and TnT was raised in 14 of them (48%; p < 0.05).Conclusion. The rise in TnT levels during EDOB suggests that this test may produce myocardial damage associated with the appearance of contractility disorders during dobutamine infusion.

Risk of embolization after institution of antibiotic therapy for infective endocarditis.

OBJECTIVES: This study was designed to assess the risk of systemic embolization in patients with left-sided infective endocarditis, once adequate antibiotic treatment had been initiated, on the basis of prospective clinical follow-up. BACKGROUND: As one of the complications of infective endocarditis, embolization has a great impact on prognosis. Prediction of an individual patient's risk of embolization is very difficult. METHODS: We studied 217 episodes of left-sided endocarditis that were experienced among a cohort of 211 prospectively recruited patients. According to the Duke criteria, 91% of the episodes were definite infective endocarditis. Seventy-two episodes involved infections located on prosthetic valves. All patients were studied by transthoracic and transesophageal echocardiography. Clinical, echocardiographic and microbiologic data were entered in a data base. The mean follow-up interval was 151 days. RESULTS: Twenty-eight episodes (12.9%; group I) of endocarditis had embolic events after the initiation of antibiotic therapy. The remaining 189 episodes did not embolize (group II). Most emboli (52%) affected the central nervous system, and 65% of the embolic events occurred during the first two weeks after initiation of antibiotic therapy. Previous embolism was associated with new embolism (relative risk [RR] 1.73, 95% confidence interval [CI] 1.02 to 2.93; p = 0.05). There was an increase in the risk of embolization with increasing vegetation size (RR 3.77, 95% CI 0.97 to 12.57; p = 0.07). Vegetation size had no impact on the risk of embolization in streptococcal endocarditis or aortic infection. By contrast, large (> or = 10 mm) vegetations had a higher incidence of embolism when the microorganism was staphylococcus (p = 0.04) and the mitral valve was infected (p = 0.03). The increase in vegetation size at follow-up showed a higher risk for embolization (RR 2.64, 95% CI 0.98 to 7.16; p = 0.02). CONCLUSIONS: Embolism before antimicrobial therapy is a risk factor for new emboli. The risk of embolization seems to increase with increasing vegetation size, and this is particularly significant in mitral endocarditis and staphylococcal endocarditis. An increase in vegetation size, despite antimicrobial treatment, may predict later embolism.

Safety of coronary stenting early after thrombolysis in patients with acute myocardial infarction: one- and six-month clinical and angiographic evolution.

To determine the feasibility and safety of early posthrombolysis coronary stenting and the incidence of further reocclusion, we followed 99 consecutive patients with acute myocardial infarction thrombolyzed with rt-PA 2.0 +/- 0.8 hr after onset. Culprit artery was stented 14.0 +/- 7.0 hr after thrombolysis. All patients underwent clinical and angiographic follow-up at 1 and 6 months. Angiographic success was achieved in 99% of cases. Neither major cardiac events nor bleeding or vascular complications occurred during hospital stay. At 30 days, no events occurred and normal flow persisted in all stented arteries. At 6 months, only one artery reoccluded (1%), resulting in a nonfatal reinfarction. Restenosis rate was 21%. Contribution of the infarcted area to left ventricular function significantly increased from baseline to 30-day and to 6-month evaluations. Thus, early posthrombolysis stenting is a safe strategy with a low reocclusion rate, which seems to allow functional recovery of the infarcted area. Further studies are necessary to define its impact on survival and cost-effectiveness.

NF-kappaB and IkappaBalpha expression following traumatic brain injury to the immature rat brain.

NF-kappaB is one of the most important modulators of stress and inflammatory gene expression in the nervous system. In the adult brain, NF-kappaB upregulation has been demonstrated in neurons and glial cells in response to experimental injury and neuropathological disorders, where it has been related to both neurodegenerative and neuroprotective activities. Accordingly, the aim of this study was to evaluate the cellular and temporal patterns of NF-kappaB activation and the expression of its endogenous inhibitor IkappaBalpha following traumatic brain injury (TBI) during the early postnatal weeks, when the brain presents elevated levels of plasticity and neuroprotection. Our results showed that cortical trauma to the 9-day-old rat brain induced a very fast upregulation of NF-kappaB, which was maximal within the first 24 hours after injury. NF-kappaB was mainly observed in neuronal cells of the degenerating cortex as well as in astrocytes located in the corpus callosum adjacent to the injury, where a pulse-like pattern of microglial NF-kappaB activation was also found. In addition, astrocytes of the corpus callosum, and microglial cells to a lower extent, also showed de novo expression of IkappaBalpha within the time of NF-kappaB activation. This study suggests an important role of NF-kappaB activation in the early mechanisms of neuronal death or survival, as well as in the development of the glial and inflammatory responses following traumatic injury to the immature rat brain.

Periannular extension of infective endocarditis.

OBJECTIVES: This prospective study was designed to assess the current clinical course, risk factors, microbiologic profile and echocardiographic findings of patients with left-sided endocarditis and perivalvular complications. BACKGROUND: Periannular complications worsen the prognosis of patients with endocarditis. The relation between these complications and the clinical and microbiologic data has not been clearly defined. METHODS: In this clinical cohort study, 211 patients with left-sided endocarditis, according to the Duke criteria, were prospectively recruited. All patients underwent conventional and transesophageal echocardiography. The mean follow-up interval was 151 days. RESULTS: Perivalvular complications were detected in 78 patients (37%). The incidence of periannular extension of infection in native and prosthetic valves was 29% and 55%, respectively. The presence of prosthesis (relative risk [RR] 1.88, 95% confidence interval [CI] 1.35 to 2.64) and previous endocarditis (RR 1.78, 95% CI 1.16 to 2.7) were the only pre-existing heart conditions associated with perivalvular complications. Aortic infection (RR 1.8, 95% CI 1.23 to 2.66) and the development of atrioventricular (AV) block (RR 2.55, 95% CI 1.91 to 3.41) were related with the existence of these complications. Coagulase-negative staphylococci were very common in patients with perivalvular complications (RR 1.77, 95% CI 1.21 to 2.59), and small vegetations were more frequent in these patients (RR l.45, 95% CI 0.95 to 2.22). An operation was more frequently performed in patients with perivalvular complications, but mortality was similar in patients with and without these complications. CONCLUSIONS: Aortic infection, prosthetic endocarditis, new AV block and coagulase-negative staphylococci were independent risk factors of periannular complications. The period between symptom onset and diagnosis, the incidence of pericardial effusion and persistent signs of infection were similar between patients with and without perivalvular complications. Patients with perivalvular complications did not demonstrate a difference in the presence or size of vegetations or the frequency of embolism. An operation was more frequently performed in these patients, but mortality was similar in both groups.

Neuropatia cronica desmielinizante inflamatoria: hallazgos en 30 pacientes / Chronic inflammatory demyelinating polyneuropathy. Findings in 30 patients

La neuropatía crónica desmielinizante inflamatoria (NCDI) constituye una entidad reconocida desde hace ya varios años, aunque su patogenia no ha sido aún dilucidada totalmente. Sin embargo, existen suficientes evidencias que sugieren que su producción es inmunomediada. Entre los años 1992 y 1997 hemos podido estudiar 30 pacientes con esta patología y que son el objeto de esta comunicación. En ellos se procedió a su estudio clínico y de laboratorio. Estos últimos comprendieron la electrofisiología de sus nervios, la inmunoelectroforesis de sus proteínas séricas, el estado físico-químico, y cuando posible, inmunológico de sus líquidos cefalorraquídeos (LCR) y la biopsia del nervio safeno externo que se llevó a cabo en algo más de la mitad de los probandos. Los hallazgos clínicos más relevantes fueron debilidad muscular, atrofias musculares, hipo a arreflexia osteotendinosa, parestesias e hipoestesias. La investigación de la capacidad de conducción de sus nervios mostró reducción de esos valores, en el rango de desmielinización, en todos ellos. La inmunoelectroforesis de las proteínas séricas detectó la existencia de gammopatía monoclonal en el 17 por ciento de los pacientes. El examen de LCR descubrió aumento de proteínas en el 79 por ciento de los probandos y la imagen histológica fue de desmielinización en los 17 enfermos que aceptaron el procedimiento. Según nuestro criterio la NCDI constituye una enfermedad con características definidas que puede ser detectada aunando los hallazgos clínicos, electrofisiológicos y de LCR. La biopsia de nervio, si bien es un elemento diagnóstico de apoyo, puede no ser necesaria para el reconocimiento de esta dolencia en la medida en que exista coherencia entre las observaciones clínicas, las de condución nerviosa y las de LCR. Su individualización temprana es de valor, ya que permite una precoz acción terapéutica evitando las eventuales secuelas que pudiera dejar.

Further studies on HTLV-I associated myelopathy in Argentina

We report 10 HTLV-I virus seropositive subjects, eight of them with HTLV-I associated myelopathy (HAM), two of them also infected with HIV as well as two asymptomatic HTLV-I+ relatives of two unrelated patients. HTLV-I is endemic in several tropical areas, where it causes different neurological diseases. Only few patients have been reported in our country since 1994. We studied 8 patients, who fulfilled the clinical criteria for chronic spastic paraplegia, and 2 other non-symptomatic HTLV-I seropositive relatives, with electromyography (EMG), motor and sensory conduction velocities (NCV), somatosensory, visual and brainstem auditory evoked potentials (SSEP, VEP and BAEP), Magnetic Resonance Images (MRI) and cerobrospinal fluid (CSF) analysis. The latter was carried out only in seven symptomatic patients. In every case positive ELISA tests for HTLV-I/II were confirmed by Western Blot. The two asymptomatic persons were clinically and electromyographically assessed, one of them was also submitted to SSEPs studies. Three patients were males. Patient's ages ranged from 5 to 65 years old. All symptomatic patients showed muscular weakness, spasticity with pyramidal signs and sphincter disturbances. Five of them had paresthesias and 2 had burning pain on their feet. The EMGS and the NCVs were normal in 7 patients and in the 2 asymptomatic ones. SSEPs, obtained by stimulating the posterior tibial nerves, were impaired in 7 patients and in the asymptomatic person who received the procedure. The 7 symptomatic patients who underwnt lumbar puncture had positive tests for HTLV-I in CSF, 3 out of these 7 patients had also high protein levels and 4 had increased number of lymphocytes. In 2 patients intrathecal IgG production could also be demonstrated. MRI were normal in 7 patients and in the 2 asymptomatics, the exception being a female who had bilateral hypertense lesions in cerebral white matter in T2. In conclusion, tropical spastic paraparesis is apparently a rare disorder in Argentina. However, some cases have been reported recently. Most probably, its prevalence is currently underestimated. Its diagnosis should be considered in every patient with progressive spastic paraplegia.

Insuficiencia cardiaca grave en el sindrome de Kearns-Sayre / Severe cardiac failure in Kearns-Sayre syndrome

Las enfermedades mitocondriales son patologías que afectan en forma primaria a la mitocondria, con repercusión clínica sistémica variada, determinando sus diversas formas clínicas. Se presenta un paciente de 19 años, que fue visto por vez primera en 1993 con un cuadro de miopatía de 10 años de evolución, diplopía, disminución de la agudeza visual y trastornos fonodeglutorios progresivos. El examen clínico evidenció atrofia muscular generalizada, ligera debilidad en la flexoextensión de cuello, hiporreflexia generalizada, dismetría en pruebas índice-índice y talón-rodilla bilateral, ptosis bipalpebral y mirada congelada. En el fondo de ojo se observó la existencia de una retinitis pigmentaria. El EMG mostró signos de compromiso primario del músculo, con velocidades de conducción nerviosa normales. El examen físico-químico de LCR fue normal, excepto por el moderado aumento del ácido láctico. La biopsia muscular mostró la existencia de un 15,4 por ciento de fibras "ragged red"y la presencia de incremento anómalo de la reactividad oxidativa mitocondrial subsarcolemal. En febrero de 1995 presentó un cuadro de insuficiencia cardíaca derecha, acompañado de empeoramiento clínico generalizado. El examen neurológico, en esta ocasión, reveló la presencia de mialgias y aumento de la debilidad muscular universal. Un ecocardiograma modo M y bidimensional, reveló ligera dilatación biventricular e hipertrofia leve del ventrículo izquierdo, con función sistólica global ventricular izquierda conservada. Una nueva biopsia muscular para estudio del DNA mitocondrial halló una cancelación común de 5 Kb, con un 80 por ciento de heteroplasmia. En definitiva, se trata de un paciente con una enfermedad mitocondrial, cuyo fenotipo correspondía al síndrome de Kearns-Sayre, que desarrolló un cuadro cardiológico compatible con una insuficiencia cardíaca aguda, debido a una miocardiopatía dilatada, asociación que ha sido descripta en la literatura con escasa frecuencia.

Lower motor neuron syndrome associated with anti-GM 1 antibodies

It has been recently recognized that increased titers of serum anti-GM1 antibodies may be associated with motoneurone diseases or with multiple motor neuropathy with or without conduction block and also with chronic sensorimotor neuropathy and Guillain-Barré syndrome. Santoro et al. were the first to note that anti-GM1 antibodies were able to bind to the nodes of Ranvier of the sural nerve of a patient with clinical signs and symptoms mostly resembling amyotrophic lateral sclerosis who also showed, in nerve conduction studies, multifocal motor nerve fibers conduction block and serum IGM anti-GM1 antibodies. The who patients presented in this report had asymetrical motor neurone disease with signs and symptoms of lower motoneurose involvement, and other signs, in the first patient, which suggested the existence of upper motoneurone damage. Besides, the second patient also had clinical sensory impairment in the lower limbs. Electrophysiologically, none of them had nerve conduction block but both showed inexcitable median and sural nerve sensory fibers. Both had high titers of anti-GM1. A sural biopsy of both patients showed immunoglobulins into the sensory fibers. However, we do not know whether the anti-GM1 antibodies bind to a cross-reactive glycolipid other than the GM1 itself. In any case, it seems that the presence of anti-GM1 antibodies might be a marker signalling a potentially treatable immune disorder which may have signs of lower and upper motor neurone disease and, also, clinical and electrophysiological evidence of peripheral sensory involvement.

Familial dwarfism and painful muscle spasms

We report a family with a disorder characterized by limbs and truncal undulating painful muscle spasms, short stature, fine and sparse hair in the scalp, absence of body hair, low implanted ears, big nose, pitched voice, enlarged heart ventricles and increased fasting glucose levels. Symptoms began in childhood and did not progress after the third decade of life. This disorder represents a new clinical phenotype among the several forms of dwarfism associated with neurological manifestations already described in the literature.

Diagnostico y tratamiento de la myasthenia gravis: experiencia 1974-1992 / Diagnosis and treatment of myasthenia gravis: experience 1974-1992

En el Hospital Ramos Mejía entre los años 1974 y 1992, se asistieron 118 pacientes con myasthenia gravis (MG). En la población adulta se observó un predominio en el sexo femenino de 1,87:1 y una mayor prevalencia en la tercera década de la vida. Las pruebas diagnósticas resultaron positivas en el siguiente orden: medición de la amplitud de los potenciales miniatura de placa (mepp's) en el ratón inyectado con suero de paciente miasténico (100 por ciento), prueba del cloruro de Edrofonio (97 por ciento), estímulo repetitivo (83 por ciento) y anticuerpos antirreceptor colinérgico (78 por ciento). Estas dos últimas pruebas resultaron positivas más frecuentemente en las formas generalizadas que en las formas oculares de la enfermedad. La neumomediastinografía con tomografía lineal mostró mayor coincidencia con el estudio anatomopatológico del timo que la TAC. La medida terapéutica más efectiva resultó ser la inmunosupresión esteroidea. El 28 por ciento de los pacientes tratados con esteroides desarrolló un deterioro transitorio al inicio de la medicación y una evolución desfavorable a largo plazo que otorgaría a este fenómeno cierto valor pronóstico. La vía de abordaje quirúrgico del timo más efectiva resultó ser la cervicotomía con manubriotomía. Con cervicotomía simple se observaron 4 casos de recidiva que debieron ser reintervenidos