Low frequency independent components: Internal neuromarkers linking cortical LFPs to behavior.

Local field potentials (LFPs) in the primate motor cortex have been shown to reflect information related to volitional movements. However, LFPs are composite signals that receive contributions from multiple neural sources, producing a complex mix of component signals. Using a blind source separation approach, we examined the components of neural activity recorded using multielectrode arrays in motor areas of macaque monkeys during a grasping and lifting task. We found a set of independent components in the low-frequency LFP with high temporal and spatial consistency associated with each task stage. We observed that ICs often arise from electrodes distributed across multiple cortical areas and provide complementary information to external behavioral markers, specifically in task stage detection and trial alignment. Taken together, our results show that it is possible to separate useful independent components of the LFP associated with specific task-related events, potentially representing internal markers of transition between cortical network states.

Plasmocitoma extramedular de canal auditivo externo: caso clínico / Extramedullary plasmacytoma of external auditory canal: a case report

Resumen El plasmocitoma extramedular es una neoplasia de células plasmáticas poco frecuente, que se ubica en 80% a 90% de los casos en la cabeza o cuello. Esta neoplasia representa menos del 1% de toda la patología maligna de cabeza y cuello. Dada la poca frecuencia de la patología y la escasez de casos publicados, esta entidad presenta una gran dificultad clínica y terapéutica. El diagnóstico se basa en el análisis histológico con inmunohistoquímica de la muestra obtenida, y el tratamiento varía según la ubicación, donde se puede realizar radioterapia o cirugía. En este artículo presentamos el caso de una paciente de 56 años, con antecedentes de otorrea de larga data en oído derecho, al examen físico presentaba un tumor que obstruía todo el conducto auditivo externo. Se realizó exéresis tumoral y la biopsia evidenció un plasmocitoma.

Abstract Extramedullary plasmacytoma is a rare plasma cell neoplasm, affecting 80% to 90% of the head or neck. This neoplasm represents less than 1% of all malignant head and neck pathology. Given the infrequency of the pathology and the scarcity of published cases, this entity presents great clinical and therapeutic difficulty. Diagnosis is based on histology and immunohistochemistry and treatment varies depending on the location, where radiation therapy or surgery can be performed. In this article, we present the case of a 56-year-old patient with a history of long-standing otorrhea in the right ear. Physical examination presented a tumor that obstructed the entire external auditory canal. Tumor excision was performed, and the biopsy revealed a plasmacytoma.

[Experience of a research Ethics Committee and the challenges of the new Chilean legislation on research in human beings]. / Experiencia del Comité de Ética de Investigación en Seres Humanos de la Facultad de Medicina de la Universidad de Chile y los desafíos que impone la nueva legislación chilena en la investigación médica.

The welfare of research participants must be guaranteed by international ethical standards. This article communicates the procedures of the Research Ethics Committee of the School of Medicine, University of Chile (CEISH). The new Chilean legislation on research in human beings is also discussed. Law 20.120: "On scientific research in human beings, its genome and forbidding human cloning" establishes the ethical principles that must be accomplished in every research involving human beings. Article 28 of the Law 20.584 "Regulation of the rights and duties of health care users", forbids the participation of handicapped people who cannot express their will in scientific research. Article 13 states that people not related directly with patient care cannot have access to his clinical records (with the exception of people with notarial authorization by the patient). CEISH proposes that, in case of people with intellectual deficiency, the decision to approve a scientific research should be analyzed on an individual basis. If the person is capable of expressing his or her will or has stated his or her consent beforehand, the research can be authorized. If the person cannot express his or her will, the scientific research cannot take place. In prospective studies, a consent from the patient and an authorization of the health authority should be required to access clinical records. In retrospective studies, consent should be obtained from the patient when personal information is going to be used. If the information is nameless, the consent can be disregarded.

Benznidazole treatment in chronic children infected with Trypanosoma cruzi: serological and molecular follow-up of patients and identification of Discrete Typing Units.

A total of 221 children from two rural settlements in Northeast Argentina were examined for T. cruzi infection. Blood samples were taken for serology tests and PCR assays. In addition, T. cruzi Discrete Typing Units (DTUs) were determined by hybridization with specific DNA probes of the minicircle hypervariable regions (mHVR). Serological results indicated that 26% (57/215) were reactive against T. cruzi antigens. PCR analyses were performed on seropositive samples showing presence of parasite DNA in 31 out of 53 samples (58.5%). All seropositive children underwent specific chemotherapy with Benznidazole (5mg/kg/day) for a period of two months and were monitored two and five years after treatment. Overall the treatment was well tolerated and low side effects were observed. Serological conversion was observed at two years post -treatment in one child form Pampa Ávila and at five years in two children from Tres Estacas. However, at the end of the follow-up period, T. cruzi DNA could not be detected by PCR in samples from treated children, except in two cases. In addition, the results of hybridizations with specific DNA probes showed that DTU TcV was detected in 68% (21/31), TcVI in 7% (2/31) and TcV/VI in 3% (1/31) of the samples. Altogether, results of the follow-up of treated children showed a low rate of seroconversion; however trend toward seroconversion was evident at five years post-treatment. On the other hand, detection of T. cruzi DNA by PCR significantly decreased after Benznidazole treatment. The existence of data regarding serological and molecular follow-ups from controlled studies in the Chaco Region will be important for future treatment efforts against T. cruzi infection in this region. The results obtained in the present study represent a contribution in this regard.

Immuno-enzymatic evaluation of the recombinant TSSA-II protein of Trypanosoma cruzi in dogs and human sera: a tool for epidemiological studies.

The rTSSA-II (recombinant Trypomastigote Small Surface II) antigen was evaluated by ELISA to detect anti-Trypanosoma cruzi antibodies in sera from naturally infected dogs and humans. For this evaluation ELISA-rTSSA-II was standardized and groups were classified according to the results obtained through xenodiagnosis, ELISA and PCR. Sensitivity (Se), Specificity (Sp), Kappa index (KI) and area under curve (AUC) were determined. The Se was determined by using 14 sera from dogs infected with T. cruzi VI (TcVI) whereas Sp was determined by using 95 non-chagasic sera by xenodiagnosis, ELISA-Homogenate and PCR. The performance of ELISA-rTSSA-II in dog sera was high (AUC=0·93 and KI=0·91). The Se was 92·85% (1 false negative) and Sp was 100%. Two sera from dogs infected with TcI and 1 with TcIII were negative. For patients infected with T. cruzi, reactivity was 87·8% (36/41), there was only 1 indeterminate, and Sp was 100%. Fifty-four sera from non-chagasic and 68 sera from patients with cutaneous leishmaniasis did not react with rTSS-II. ELISA-rTSSA-II showed a high performance when studying sera from naturally infected dogs and it also presented 100% Sp. This assay could be an important tool to carry out sero-epidemiological surveys on the prevalence of T. cruzi circulating lineages in the region.

Avances en la clínica de las adicciones: el rol del aprendizaje y la dopamina / Update in the clinic of addictions: learning and dopamine

There are two parallel explanatory models for addictions. One is the homeostatic model, that explains tolerance and the abstinence syndrome. Tolerance and abstinence are reversible phenomena that mask sensitization. These appear more commonly with the continued use of drugs, and are based in the up-regulation of cyclic AMP. The other is the plasticity model, that explains sensitization and compulsive use of drugs or addiction. Addiction is probably irreversible, underlies tolerance, appears more frequently with intermittent use of drugs, and is based in learning and memory mechanisms. Both are boldly linked to environmental and behavioral elements. In the plasticity model, dopamine (DA) has an outstanding role. Its phasic discharge is a temporal reward prediction error marker. It is the prediction error that generates learning. All the addictive drugs provoke a very strong increase of phasic DA discharge in some cerebral nuclei by direct or indirect paths. This increase is interpreted by cerebral circuits as prediction errors that generate learning behaviors. Pavlovian and operating type learning is involved. It is clinically observed as the prominence of environmental cues that are related to drug consumption, and the appearance of behaviors directed to the search and use of drugs, that are mainly involuntary and triggered by these cues. Pleasure (primary reinforcement) plays a role in this model, only in the initial stages of addiction. Understanding this double parallel model allows to design therapeutic interventions directed towards a conscious control of involuntary, environmental and affective cues that trigger drug search and use.

Modelos neurocognitivos en la esquizofrenia: rol del córtex prefrontal / Neurocognitive models of schizophrenia: the prefrontal cortex role

Los modelos neurocognitivos han dado lugar a un importante avance en la comprensión de diversos desórdenes mentales tales como la esquizofrenia (EQZ). En ese contexto, la disfunción del córtex prefrontal (CPF) es un hallazgo central para explicar su sintomatología. Se ha observado que los niveles anormales de activación de la CPF, así como disfunciones en la conectividad con otras estructuras cerebrales, juegan un importante rol en la delimitación de la enfermedad. Material y Métodos: A través de una revisión teórica, empírica y clínica se describirán cinco aproximaciones neurocognitivas de la esquizofrenia. Conclusiones: Aunque la etiología de la EQZ es probablemente múltiple, un desorden de la interconectividad neuronal, y especialmente de la CPF explican un amplio espectro de su sintomatología.

Introduction: Neurocognitive models gave place to an important improvement in our understanding of several mental disorders such as schizophrenia. In this context, Prefrontal cortex (PFC) dysfunction is an essential variable for its symptomatology account. It has been observed that abnormal level of PFC activation, as well as connectivity dysfunctions with other cerebral structures, play a central role in the delimitation of the disease. Materials and Methods: Through a theoretical, empirical, and clinical review, five neurocognitive approach of schizophrenia will be described. Conclusion: Although schizophrenia etiology is probably multiple, neural interconnectivity disorders and specially those related to PFC, explain a broad range of its symptoms.

Trastornos de ansiedad en pacientes hospitalizados en Medicina Interna / Anxiety disorders among patients hospitalized in a medical ward

Background: Anxiety symptoms and anxiety disorders are common among medical patients, however few studies differentiate both and consider the psychiatric comorbidity of anxiety disorders among such patients. Aim: To evaluate the presence of anxiety disorders among patients admitted to a medical ward. Patients and methods: Random selection of 406 patients (mean age 56 years, 203 female), hospitalized in a medical ward of a public hospital, mainly for cardiovascular, genitourinary and digestive diseases. All were assessed using an structured interview for DSM-III-R. Results: Twenty six percent of women and 13% of men had anxiety disorders. Fifteen percent of women and 6% of men had specific phobias, 7% of women and 4% of men had generalized anxiety, 5% of women and 0.5% of men had agoraphobia, 3% of women and 0.5% of men had social phobia, 1% of men and 0.5% of women had panic disorders and 0.5% of women had a post traumatic stress. Specific phobias and social phobias started during childhood. Anxiety and agoraphobia started during adulthood. Among patients with anxiety disorders, 43% of women and 34% of men did not have other psychiatric ailment, 34% of women and 19% of men had an associated depression and 34% of men had disorders due to use of alcohol. Conclusions: A high proportion of patients hospitalized in medical wards have anxiety disorders, that once identified it may help to treat the medical ailments.

Tratamiento quirúrgico de las ulceras por presión en pacientes con daño cerebral irreversible por traumatismo encefalocraneano / Surgical treatment of presure sores in pacients wit postraumatic brain injury

Producto de nuestro moderno estilo de vida, los traumatismos encéfalocraneanos (TEC) son una importante causa de morbimortalidad; afectando especialmente a población joven. Algunos pacientes pueden quedar con graves secuelas neurológicas, en estado vegetativo y permanentemente postrados. Por otra parte, la mejor atención, tanto en fase aguda como crónica, ha mejorado su expectativa de vida, apareciendo complicaciones que plantean nuevos desafíos terapéuticos, entre las que se incluyen las úlceras por presión (UP). Tradicionalmente, en nuestro medio, las UP en estos pacientes han sido tratadas de forma conservadora. Sin embargo, esta conducta. muchas veces implica. curaciones por largos períodos de tiempo, significando un deterioro en la calidad de vida del enfermo, una carga adicional para los familiares y un encarecimiento para las instituciones de salud. Por estos motivos presentamos la experiencia del Hospital del Trabajador de Santiago, en el tratamiento quirúrgico de 7 pacientes con graves secuelas neurológicas post TEC, portadores de UP, 5 sacras y 2 trocantéreas; planteándose la cirugía como una alternativa válida ele tratamiento. Se discuten algunos aspectos relevantes a su evaluación preoperatoria, tipo de cirugía, evolución, complicaciones, resultados y costos (AU)

The craneal trauma is, actually, an important etiology of morbity and mortality, mainly in young people. Some of these patients lay in bed for ever, with importants neurological sequelaes secondary to their brain injury. In the other hand the berter attention in acute as well as cronic phase have improve their expectative of Iife, appearing complications with new challenges such as the pressure sores. Traditionally, in our environment these pressure sores, in the these pauents, have been treated in conservative way. Nevertheless, these treatments mean wounds cares for long times, with a detrimental quality of Iife for the patient, an emotional comminent for their relatives ancl a big investment for the Hospital del Trabajador Santiago. Chile in the surgical treatment of 7 patients with important neurological sequeales post brain injury and with pressure sores: 5 sacral, and 2 trocanterics. Pre operatory evaluation, type of surgery, evolution, complications, results and costare discussed (AU)

Prevalencia de trastornos psiquiátricos por uso de alcohol y otras sustancias en hombres y mujeres hospitalizados en medicina interna de un hospital de Santiago de Chile / Prevalence of substance abuse among patients hospitalized in an internal medicine service from Santiago de Chile

Background: Studies done in Chile and abroad report a high frequency of substance abuse among patients hospitalized in general medical services. Aim: To report the frequency of substance abuse in a sample of patients hospitalized in a public hospital of Santiago. Material and methods: A structured psychiatric interview for the Third Revised Version of The Diagnostic and Statistical Manual (DSM-III-R) was applied to 203 males, aged 58.5 years and 203 females, aged 52,9 years, hospitalized in an internal medicine Service of a public hospital. All subjects had a low educational and income level. Results: The discharge diagnoses of studied patients were digestive diseases in 32 percent, circulatory diseases in 19 percent, cancer, diabetes mellitus and genitourinary diseases in 11 percent respectively and mental or behavioral diseases in 5 percent. Thirty eight percent of males and 6 percent of females qualified for alcohol dependency or abuse in some moment of their lives. The figures for benzodiazepine dependency were 1 percent among males and 6 percent among females. The figures for cannabis, cocaine or stimulant abuse were 1.5 percent for males and 1 percent for females. Other conditions of the axis 1 of DSM-IIIR were diagnosed in 47 percent of males and 65 percent of females with substance abuse. Conclusions: Substance abuse underlies medical conditions in a high proportion of patients admitted to medical services in general hospitals

Prevalencia de trastornos psiquiátricos en hombres y mujeres hospitalizados en un servicio de medicina interna de un hospital de Santiago de Chile / Prevalence of psychiatric disorders among subjects hospitalized in a medicine ward of a general hospital

Background: Mental disorders may interfere, aggravate or mimic medical conditions. Aim: To study the prevalence of psychiatric disorders among patients hospitalized in a medical ward of a general hospital. Patients and methods: A structured interview for DSM-III, devised for "non patients", was applied to 203 men and 203 women, aged 11 to 90 years old, hospitalized in an internal medicine service of a public hospital. Thirty four psychiatric conditions that can be discriminated with the instrument and others that complied with DSM-III criteria, were investigated. Results: There was a 60 percent prevalence of mental disorders among men (alcohol dependency in 26 percent, delirium or dementia in 10.8 percent, anxiety disorders in 10.4 percent, major depression in 7.8 percent and adaptation disorders in 3 percent). Among women, the prevalence of mental disorders was 65 percent (major depression in 23.2 percent, anxiety disorders in 14.3 percent, adaptation disorders in 8.4 percent, dementia in 5.6 percent, delirium in 3 percent and alcohol dependency in 2.5 percent). Most conditions were of moderate or mild intensity. Two or more conditions coexisted in 40 percent of cases. Only in 8 percent of these subjects, a psychiatric consultation was requested. Conclusions: There is a high frequency of psychiatric disorders among medical patients. These must be adequately diagnosed and treated

Diabetes mellitus descompensada y acidosis metabólica hiperclorémica: asociación de patologías en un caso / Association of hyperglycemia and hyperchloremic acidosis in a diabetic patient

Diabetic ketoacidosis is manifested by elevated blood glucose levels, ketosis and metabolic acidosis with increased anion gap. A transitory hyperchloremic acidosis. with normal anion gap, can appear. We report a 21 years old female with a type 2 diabetes mellitus, admitted to the emergency room of a general hospital with hyperglycemia, absence of ketonemia, severe hypokalemia and hyperchloremic metabolic acidosis. Initially, she was diagnosed and treated as a severe diabetic ketoacidosis. Normal blood glucose levels were rapidly achieved but electrolyte and acid base alterations persisted, leading to the suspicion that another associated condition was causing the acidosis and hypokalemia. Urinary pH and anion gap measurement, the study of renal acidification and a bicarbonate overload test lead to the diagnosis of a distal renal tubular acidosis, secondary to a Sjögren syndrome, that was confirmed with a Schirmer test and positive anti Ro antibodies. In this diabetic patient, the acute hyperglycemia intensified the hypokalemia of her distal renal tubular acidosis and unchained the acute metabolic condition

La conducta suicida en mujeres: un estudio prospectivo / Study of female suicide attempters: a 5 years follow up

Background: A previous suicide attempt is one of the strongest predictors of future suicidal behavior. Aim: To explore the evolution of suicidal tendencies in women who attempted suicide 5 to 7 years earlier. Patients and methods: Ninety two women aged 37 ñ 9 years old, that attempted suicide between 1989 and 1991 were followed and reassessed in 1997. Results: In the study period two women committed suicide and 30 attempted suicide. Forty three percent of new self harm behaviors occurred during the first year after the first suicide attempt and the harming method was similar. Conclusions: In this study, 34percent of women with previous suicide attempts, repeated this behavior, using similar methods

Anticoagulación en hemodiálisis con dósis única de heparina de bajo peso molecular / Anticoagulation during hemodialysis with a single dose of low molecular weight heparin

The aim of this work was to compare the benefits and problems of low molecular weight heparin use in chronic hemodialysis, compared to conventional heparin. We studied 35 patients that received low molecular weight heparine (Enoxaparine, molecular weight 4000) during 115 consecutive hemodialysis procedures and conventional heparin during the subsequent 35 procedures. We assessed the heparin dose, partial thromboplastin time before dialysis and at 3 and 120 min during the procedure, arterio-venous fistula compression time, clot formation in the circuit and residual volume of filters. Median total dose of conventional heparin was 6289 U (range 3000-10000) compared to 5555 U (range 2000-8000) of low molecular weight heparin. When the dose was calculated per kg of body weight, it was lower for low molecular weight heparin than for conventional heparin (87.8 U (range 33-100) vs 100 U (range 50-176). Partial thromboplastin time achieved was lower with low molecular weight heparin, compared with conventional heparin, at 3 (64.26 vs 125.2 sec) and 120 min (39.1 vs 84.45 sec). Clot formation, arteriovenous fistula compression time and residual volume of filters were similar for both types of heparin. It is concluded that a single dose of low molecular weight heparin simplifies anticoagulation during hemodialysis, modifies less the partial thromboplastin time and does not alter filter re-utilization

[Assays of apolipoproteins A and B as atherogenicity factors in aged patients at hospitals]. / Dosages des apolipoprotéines A et B comme facteurs d'athérogénécité chez les personnes âgées en milieu hospitalier.

A systematic study of 100 elderly patients in a hospital geriatric unit was undertaken to analyse the relationship between clinical cardiovascular events (angina, myocardial infarction, hypertension, cerebrovascular accidents, temporo-spatial disorientation, invalidity, incontinence) and plasma lipids (total cholesterol, HDL and LDL fractions, triglycerides, apolipoprotein A and B and total cholesterol/HDL and apolipoprotein B/A ratios). The average triglyceride and apolipoprotein A concentrations were related to the patient's validity: The triglycerides were significantly higher in the group of invalid patients (+22%), p = 0.05. The apolipoprotein A levels were significantly lower in the invalid group (-12%), p = 0.05.

Estudio clínico-descriptivo del síndrome de Cotard / Clinical-descriptive study of Cotard's syndrome

Con motivo de la presentación de un caso de un niño con un violento síndrome de hiperpirexia ficticia se hace una exposición diagnóstica diferenciativa de los diversos síndromes de autoinducción voluntaria o síndromes de ficción y se aislan de ellos los cuadros clínicos de histerismo y de simulación simple. Se comenta también el concepto moderno del síndrome de Münchhausen y el sentido terapéutico actual de todos estos procesos