The charming physician (El médico encantador): neurological conditions in a short story by Silvina Ocampo / O médico encantador (El médico encantador): doenças neurológicas em um conto de Silvina Ocampo

ABSTRACT The Argentinian author Silvina Ocampo (1903-1993) left us a vast body of works which are considered outstanding in many ways. In 1960, she published a short story, entitled "El médico encantador" (The Charming Physician), in the renowned literary magazine Sur. The central character of this piece is a family doctor named Albino Morgan, who had a secret truth: in any house he visited, all variety of disease also entered. He brought with him the viruses he disseminated. The narrator of this short story—one of his patients—describes four of Morgan's diseases. These imaginary neurological conditions allowed Ocampo to explore improbable situations in everyday life.

RESUMO A autora argentina Silvina Ocampo (1903-1993) deixou-nos uma vasta obra que é considerada excelente de várias maneiras. Em 1960, publicou um conto, intitulado "El médico encantador" (O médico encantador), na famosa revista literária Sur. O personagem principal desta obra é um médico de família chamado Albino Morgan que possuía uma verdade secreta: em qualquer casa que ele visitava, também entrava toda a diversidade de doenças. O narrador deste conto -um dos seus pacientes- descreve quatro das doenças de Morgan. Estas condições neurológicas imaginárias permitiu a Ocampo explorar as situações improváveis da vida quotidiana.

Heart Rate and Systolic Blood Pressure Variability on Recently Diagnosed Diabetics / Variabilidade da Frequência Cardíaca e da Pressão Arterial Sistólica em Diabéticos com Diagnóstico Recente

Background:Diabetes affects approximately 250 million people in the world. Cardiovascular autonomic neuropathy is a common complication of diabetes that leads to severe postural hypotension, exercise intolerance, and increased incidence of silent myocardial infarction.Objective:To determine the variability of heart rate (HR) and systolic blood pressure (SBP) in recently diagnosed diabetic patients.Methods:The study included 30 patients with a diagnosis of type 2 diabetes of less than 2 years and 30 healthy controls. We used a Finapres® device to measure during five minutes beat-to-beat HR and blood pressure in three experimental conditions: supine position, standing position, and rhythmic breathing at 0.1 Hz. The results were analyzed in the time and frequency domains.Results:In the HR analysis, statistically significant differences were found in the time domain, specifically on short-term values such as standard deviation of NN intervals (SDNN), root mean square of successive differences (RMSSD), and number of pairs of successive NNs that differ by more than 50 ms (pNN50). In the BP analysis, there were no significant differences, but there was a sympathetic dominance in all three conditions. The baroreflex sensitivity (BRS) decreased in patients with early diabetes compared with healthy subjects during the standing maneuver.Conclusions:There is a decrease in HR variability in patients with early type 2 diabetes. No changes were observed in the BP analysis in the supine position, but there were changes in BRS with the standing maneuver, probably due to sympathetic hyperactivity.

Fundamento:O diabetes afeta aproximadamente 250 milhões de pessoas no mundo. A neuropatia autonômica cardiovascular é uma complicação comum do diabetes que leva à hipotensão postural grave, intolerância ao exercício e aumento na incidência de infarto do miocárdio silencioso.Objetivo:Determinar a variabilidade da frequência cardíaca (FC) e da pressão arterial sistólica (PAS) em pacientes diabéticos com diagnóstico recente.Métodos:O estudo incluiu 30 pacientes com diabetes tipo 2 diagnosticado há menos de 2 anos e 30 controles saudáveis. Nós utilizamos o dispositivo Finapres® para medir durante cinco minutos a FC batimento-a-batimento e a pressão arterial (PA) em três condições experimentais: posição supina, em pé e durante respiração rítmica na frequência de 0,1 Hz. Os resultados foram analisados nos domínios do tempo e da frequência.Resultados:Em relação à FC, foram encontradas diferenças estatisticamente significativas nos valores da análise do domínio do tempo, especificamente em valores determinados a curto prazo, tais como o desvio-padrão dos intervalos NN (DPNN), a raiz quadrada da média das diferenças sucessivas (RQMDS) para a FC e o número de pares de NNs sucessivos que diferem em mais de 50 ms (pNN50). Não houve diferença significativa na análise da PA, mas houve uma dominância simpática nas três condições. A sensibilidade do barorreflexo (SBR) esteve diminuída em pacientes com diabetes de início recente, em comparação aos indivíduos saudáveis durante execução da manobra na posição ortostática.Conclusões:Há uma diminuição na variabilidade da FC em pacientes com diabetes tipo 2 de início recente. Não foram observadas alterações na análise da PA na posição supina, mas a SBR apresentou mudança com a manobra em pé provavelmente causada por hiperatividade simpática.

Cardiovascular variability in Mexican patients with Parkinson's disease / Variabilidade cardiovascular em pacientes mexicanos com doença de Parkinson

Cardiovascular variability (CVV) has been evaluated in patients with Parkinson's disease (PD) in other countries and exhibit ethnic differences. Objective We investigated heart rate variability (HRV) and blood pressure variability (BPV) in Mexican patients with PD. Method We further compared HRV and BPV between this group and young healthy controls (YHC) in order to estimate, for the first time in our country, the magnitude of the difference. Twenty patients were examined. Time- and frequency-domain CVV parameters were studied during supine rest (SR), active standing (AS) and controlled breathing. These measurements were compared to those of 20 YHC. Results In the three conditions tested, our study showed a decrease in almost all HRV parameters in PD patients; on the contrary, decreased BPV parameters were found less frequently and only during SR and AS. Conclusion Our results indicate that HRV is impaired in PD. Some BPV parameters are also diminished. .

A variabilidade cardiovascular (VCV) tem sido avaliada em doentes parkinsonianos em vários países e apresenta diferenças étnicas. Objetivo Investigar a variabilidade da frequência cardíaca (VFC) e a variabilidade da pressão arterial (VPA) em doentes parkinsonianos mexicanos. Método Comparamos VFC e VPA entre o grupo de estudo e controles jovens (CJ), a fim de estimar a magnitude da diferença. CVV foi estudada no domínio do tempo e da frequência durante repouso supino (RS), ortostase ativa (OA) e respiração controlada. Estas medições foram comparadas com aquelas de 20 CJ. Resultados Nosso estudo mostrou diminuição em quase todos os parâmetros da VFC em doentes parkinsonianos. A diminuição dos parâmetros da VPA foi encontrada com menos frequência. Conclusão Nossos resultados indicam que a VFC é prejudicada na doença de Parkinson. Alguns parâmetros do VPA também são reduzidos. .

Initial circulatory response to active standing in Parkinson's disease without typical orthostatic hypotension / Resposta circulatoria inicial apos ortostatismo ativo na doenca de Parkinson sem hipotensao ortostatica tipica

While the circulatory response to orthostatic stress has been already evaluated in Parkinson's disease patients without typical orthostatic hypotension (PD-TOH), there is an initial response to the upright position which is uniquely associated with active standing (AS). We sought to assess this response and to compare it to that seen in young healthy controls (YHC). Method In 10 PD-TOH patients (8 males, 60±7 years, Hoehn and Yahr ≤3) the changes in systolic blood pressure (SBP) and heart rate that occur in the first 30 seconds (sec) of standing were examined. Both parameters were non-invasively and continuously monitored using the volume-clamp method by Peñáz and the Physiocal criteria by Wesseling. The choice of sample points was prompted by the results of previous studies. These sample points were compared to those of 10 YHC (8 males, 32±8 years). Results The main finding of the present investigation was an increased time between the AS onset and SBP overshoot in PD-TOH group (24±4 vs. 19±3 sec; p<0.05). Conclusion This delay might reflect a prolonged latency in the baroreflex-mediated vascular resistance response, but more studies are needed to confirm this preliminary hypothesis. .

Apesar da resposta circulatória ao estresse ortostático já foi estudada em pacientes com doença de Parkinson sem hipotensão ortostática típica (PD-TOH), não há uma resposta inicial que é exclusivamente associada com o ortostase ativa (AS). Portanto, buscou-se avaliar esta resposta e compará-la à observada em jovens saudáveis (YHC). Método Em 10 PD-TOH pacientes (8 homens, 60±7 anos, Hoehn e Yahr ≤3) as mudanças na pressão arterial sistólica (PAS) e da frequência cardíaca que ocorrem nos primeiros 30 segundos (seg) de pé foram examinados. Ambos parâmetros foram monitorizados continuamente através do método Peňáz e os critérios de Wesseling. Os pontos de amostragem foram escolhidos com base em estudos anteriores. Estes pontos foram comparados com os de 10 YHC (32±8 anos). Resultados O principal achado deste estudo foi o aumento do tempo entre o início de AS e rebote sistólica no grupo PD-TOH (24±4 vs 19±3 seg, p<0,05). Conclusão Este atraso pode refletir uma latência prolongada na resposta da resistência vascular mediado pelo barorreflexo, mas outros estudos são necessários para confirmar esta hipótese preliminar. .

Acido, ergo sum: Holger Hydén – the neuroscientist in Cortázar's Hopscotch / Acido, ergo sum: Holger Hydén – o neurocientista em O Jogo da Amarelinha, de Cortázar

The fictional Italian author Morelli is throughout the novel “Hopscotch” (1963) Julio Cortázar's alter ego. This character proposes an unoriginal literary hypothesis in chapter 62. There is an allusion to a particular Swedish that ‘is working on a chemical theory of thought.’ The Swedish neuroscientist under analysis is Holger Hydén (1917-2000), by then professor and chairman of the Department of Histology at the University of Göteborg. Hydén, who was the first to work in neurobiological micromethods, is mentioned by Morelli due to his participation in a symposium held at the end of January 1961, in San Francisco. His pioneering work will never be completely forgotten, because Hydén's neuroscientific legacy lives and will live in Cortázar's “Hopscotch”.

O autor italiano de ficção Morelli atua, no romance “Jogo da Amarelinha” (1963), como o alter ego de Julio Cortázar. Este personagem propõe uma hipótese literária sem originalidade no capítulo 62. Há uma alusão a um sueco em particular que “está trabalhando em uma teoria química do pensamento”. O neurocientista sueco em questão é Holger Hydén (1917-2000), então professor e diretor do Departamento de Histologia da Universidade de Gotemburgo. Hydén, que foi o primeiro no uso de métodos para a microdissecção de neurônios individuais, é mencionado por Morelli devido a sua participação em um simpósio realizado em São Francisco, no final de janeiro de 1961. Seu trabalho pioneiro nunca será esquecido completamente porque seu legado neurocientífico vive e vai viver em “Jogo da Amarelinha”, de Cortázar.

Breve historia del reflejo barorreceptor: de Claude Bernard a Arthur C. Guyton. Ilustrada con algunos experimentos clásicos / A brief history of the baroreceptor reflex: From Claude Bernard to Arthur C. Guyton. Illustrated with some classical experiments

El reflejo barorreceptor es poco conocido por la mayoría de los médicos a pesar de que es fundamental en la estabilización de la presión arterial latido a latido y es crucial para la supervivencia. Su fascinante historia es brevemente revisada en este artículo. En 1852 Claude Bernard descubrió que los nervios simpáticos del cuello inervan los vasos sanguíneos de la piel. En 1932 Edgar Douglas Adrian demostró que los nervios simpáticos que inervan los vasos sanguíneos de la piel descargan en forma espontánea a una frecuencia de cuatro a seis por segundo y de esta forma encontró las bases fisiológicas del tono vasomotor. En el siglo XIX Ludwig Traube y Karl Constantine Ewald Hering descubrieron que la presión arterial fluctúa sincrónicamente con la respiración y Sigmund Mayer observó que también existían oscilaciones más lentas no relacionadas con la respiración. En 1921 Heinrich Ewald Hering mostró la existencia de barorreceptores de alta presión en los senos carotideos y probó que la estimulación de los nervios aferentes que inervan estos receptores induce bradicardia e hipotensión. Estos estudios fueron más tarde avanzados por Corneille Heymans quien ganó el premio Nobel por estos estudios en 1938. En la época de los setentas Cowley y Guyton produjeron denervación sino-aórtica en los perros y de esta manera demostraron la importancia fundamental del reflejo barorreceptor en la estabilización de la presión arterial.

The baroreceptor reflex is poorly known by most physicians even though is fundamental in stabilizing the blood pressure on a beat to beat basis and is crucial for survival. Its fascinating history is briefy reviewed in this article. In 1852 Claude Bernard discovered that the sympathetic nerves of the neck innervate the blood vessels of the skin of the rabbit. Edgar Douglas Adrian in 1932 demonstrated that the sympathetic nerves that innervate the blood vessels discharge spontaneously at a rate of 4-6 per second and thus discovered the physiological basis of the vasomotor tone. In the XIX century Ludwig Traube and Karl Constantine Ewald Hering discovered that blood pressure fluctuates synchronously with respiratory movements and Sigmund Mayer observed that there are also slow non respiratory fluctuations of blood pressure. In 1921 Heinrich Ewald Hering found that high pressure baroreceptors are located in the carotid sinuses and demonstrated that the stimulation of the afferent nerve that innervates it induces bradycardia and hypotension. These studies were further advanced by Corneille Heymans who won the Nobel Prize for these studies in 1938. Later Cowley and Guyton produced sino-aortic denervation in dogs and thereby could demonstrate the fundamental importance of the baroreceptor reflex in the stabilization of blood pressure.

Control neural de la circulación periférica y de la presión arterial / Neural control of the peripheral circulation and blood pressure

In the XIX century Claude Bernard discovered the action of the nervous system on the peripheral circulation. In the first half of the XX century Ewald Hering discovered the baro-receptor and the reflex control of the heart rate and blood pressure. Cowley and Guyton demonstrated that sino-aortic denervation induces persistent changes in the blood pressure in the dog. The autonomic nervous system is mainly responsible for the regulation of the circulation and blood pressure in the short term on a beat to beat basis. It controls the vasomotor tone, the heart rate and the cardiac output. With the advent of non invasive methods that measure the blood pressure on a beat to beat basis (Finapres) and with the methods of measurement of the variability of the blood pressure in the frequency domain (spectral analysis) we can currently measure many variables including heart rate, blood pressure, stroke volume, peripheral resistances and the baroreceptor sensitivity and make some inferences about their control mechanisms. These variables can be measured at rest in the supine position, standing up, during rhythmic breathing and during the Valsalva maneuver. In this article we present a review of the neural control of the blood pressure and heart rate.

A case of tactile agnosia with a lesion restricted to the post-central gyrus.

Tactile agnosia has been described after lesions of the primary sensory cortex but the exact location and extension of those lesions is not clear. We report the clinical features and imaging findings in a patient with an acute ischemic stroke restricted to the primary sensory area (S1). A 73-year-old man had a sudden onset of a left alien hand, without left hemiparesis. Neurological examination showed intact primary sensory functions, but impaired recognition of shape, size (macrogeometrical) and texture (microgeometrical) of objects; damage confined to the post-central gyrus, sparing the posterior parietal cortex was demonstrated on MRI. An embolic occlusion of the anterior parietal artery was suspected as mechanism of stroke. Tactile agnosia with impaired microgeometrical and macrogeometrical features' recognition can result from a single lesion in the primary sensory cortex (S1) in the right parietal hemisphere, sparing other regions of the cerebral cortex which presumably participate in tactile object recognition.

Respiratory and non respiratory oscillations of the skin blood flow: a window to the function of the sympathetic fibers to the skin blood vessels

OBJECTIVE OF THE STUDY: The skin blood flow (SBF) has been known to oscillate in frequency and amplitude. The nature and type of these oscillations have remained obscure. We studied the oscillations of the SBF in frequency and amplitude with non invasive techniques during normal breathing at rest and compared it to the oscillations during rhythmic paced breathing at 6 cycles per minute. SUBJECTS AND METHODS: Thirty healthy subjects were studied under normothermic conditions. The following variables were recorded: 1) EKG signal; 2) SBF signal given by an infrared photoplethysmograph; 3) respiratory movements (RM). A correlation of the frequency of the respiration, the SBF and the EKG was made. The variability of the amplitudes of the SBF, RR intervals and pulse intervals was analyzed in the time domain and with spectral analysis using Fourier analysis. RESULTS: We found no clear respiratory modulation of the amplitude of the SBF during natural breathing at rest. With default breathing there was a low frequency oscillations (LF 0.04 to 0.15 Hz) modulation of the amplitude of the SBF that was non respiratory in nature. During rhythmic breathing at 0.1 Hz there was a strong modulation at LF of the SBF with a typical waxing and waning appearance, decreasing in amplitude during the tachycardia period and increasing in amplitude during the bradycardia period. CONCLUSIONS: Under normothermic conditions there is a consistent variability of the frequency and amplitude of the SBF with normal and rhythmic breathing. While breathing at rest the modulation of SBF amplitude was clearly seen at LF and non respiratory related. With rhythmic breathing there is a strong modulation of amplitude and frequency at the respiratory frequency.

Análisis del factor de impacto de las revistas científicas latinoamericanas / Impact factor of Latin American medical journals

Background: Latin American medical journals have a low impact factor. Higher quality articles originated in Latin American countries are published in North American or European journals. Aim: To analyze the impact factor of Latin-American journals according to the language of publication. Material and methods: The data base of periodic journals of the Thomson ISI (Journal of Citation Report) in the year 2004 was used for the analysis. Four countries with more than one journal in the data base of the Thomson ISI were included (Argentina, Brazil, Chile and Mexico). Results: Few Latin-American journals are included in the Thomson ISI data base. The mean impact factor was 0.76 (0.23-3.2) for eight Mexican journals, 0.66 (0.10-2.1) for eight Chilean journals, 0.39 (0.06-0.7) for five Argentinian journals and 0.41 (0.09-1.1) for 16 Brazilian journals. The mean impact factor for 11 journals written in English was 0.74 (0.12-2.1), 0.53 (0.09-3.2) for 18 bilingual journals and 0.28 (0.06-0.56) for eight journals written in native language. The differences between countries and languages were not statistically significant. Conclusions: The journal impact factor was similar in the four countries studied. A non-significant higher impact factor was observed in Latin-American journals published in English.

Síndrome de Raynaud secundario: disminución del flujo sanguíneo de la piel entre los episodios isquémicos y prolongación de la vasoconstricción con las maniobras respiratorias / Secondary Raynaud's syndrome: skin blood flow decrease between the ischemic episodes and prolongation of the vasoconstriction during the respiratory maneuvers

El síndrome de Raynaud se caracteriza por isquemia cutánea digital episódica, manifestada por palidez, cianosis y rubor de los dedos de manos y pies expuestos al frío o cuando el paciente está sujeto a un estrés emocional. No se conoce el mecanismo fisiopatológico exacto; la hipótesis más invocada es una alteración autonómica en la inervación simpática de los vasos sanguíneos de la piel. Objetivo: Estudiar los cambios de la frecuencia cardíaca y el flujo sanguíneo de la piel (FSP) en sujetos sanos y en pacientes con síndrome de Raynaud durante las siguientes condiciones: 1. respiración espontánea (RE), 2. respiración rítmica (RR), 3. inspiración profunda repentina (IPR), 4. maniobra de Valsalva (MV). Método: Se estudiaron 22 sujetos sanos y 22 pacientes con síndrome de Raynaud secundario. Las variables medidas fueron: 1. intervalo R-R; 2. amplitud de FSP; 3. porcentaje de disminución de FSP; 4. latencia de la máxima disminución del FSP. Resultados: Los pacientes con síndrome de Raynaud presentaron mayor taquicardia basal. La amplitud del FSP se encontró disminuido durante la respiración espontánea y durante las maniobras respiratorias (P < 0.001). La vasoconstricción estuvo prolongada ya que la latencia promedio de recuperación del FSP estuvo prolongada en IPR y MV en comparación de los sujetos controles. Conclusión: La amplitud del FSP basal está disminuida en los pacientes con síndrome de Raynaud, durante períodos asintomáticos; esto sugiere daño endotelial. También se encontró disminuido con las diversas maniobras respiratorias (RR, IPR y MV). Este cambio dinámico sugiere hiperactividad simpática hacia los vasos sanguíneos de la piel.

The Raynaud's syndrome is an episodic skin ischemia manifested by pallor, cyanosis and erythema of the fingers in response to cold or emotional stress. The exact pathophysiology is unknown but it has been hypothetised that may be due to an autonomic alteration in the sympathetic innervation of skin blood vessels. Objective: To study the changes of heart rate and skin bloodflow (SBF) in healthy subjects and in patients with secondary Raynaud's syndrome during different respiratory maneuvers: 1. spontaneous respiration; 2. rhythmic respirations (RR), 3. sudden inspirations (SI), and 4. Valsalva maneuver (VM). Methods: We studied 22 healthy subjects and 22 patients with secondary Raynaud's syndrome. The variables measured were: 1) RR intervals; 2) amplitudes of SBF; 3) percentage of decrease of SBF; 4) latency of the maximum decrease of SBF. Results: In all patients with secondary Raynaud's syndrome the SBF was decreased basally during spontaneous respirations and during all respiratory maneuvers (p < 0.001). The mean latency of recovery of the SBF was prolonged during sudden deep inspiration. The patients with Raynaud also had significant basal tachycardia at rest (p < 0.003). Conclusions: The basal skin blood flow during spontaneous respirations and in asymptomatic periods is decreased in patients with Raynaud's syndrome; this may be related to endothelial arterioral damage. The SBF was also significantly decreased dynamically during sudde3n inspirations (SI), rhythmic breathing (RR) and Valsalva maneuver (VM). This dynamic change suggests sympathetic hyperactivity.

Respuesta del flujo sanguíneo de la piel con diferentes maniobras respiratorias en sujetos sanos / Response of skin blood flow to several respiratory maneuvers in healthy subjects

INTRODUCTION: In the diagnosis of autonomic disturbances, the variability of skin blood flow (SBF) and the sympathetic skin response (SSR) in response to several respiratory maneuvers are not routinely studied. OBJECTIVE: We sought to standardize the method of SBF variability and SSR in healthy subjects during four respiratory maneuvers: 1) spontaneous breathing (SB); 2) rhythmic breathing at a rate of 6 per minute (RB); 3) sudden deep inspiration (SDI); 4) Valsalva maneuver (VM). SUBJECTS, MATERIAL AND METHOD: We studied 30 healthy subjects with a mean age of 32 years, 60 were men and 40 women. We used a photopletysmograph in the finger pad to measure SBF and surface electrodes on the palms of the hand to register the SSR. We also recorded the ECG and the respiratory movements. The variables were: 1) amplitude of SBF; 2) latency and duration of SSR; 3) percentage of decrease of the SBF during the maneuvers compared with the basal flow. RESULTS: During spontaneous breathing there was no respiratory modulation of the SBF and during RB the SBF was modulated with respiration. With SDI there was a 60 decrease of the SBF. VM induced a larger SBF decrease of 72 per cent. A significant statistical difference was revealed when we compared the decrease of SBF basal breathing with SDI and VM (P < 0.001). The difference was also significant between the SDI and VM (P < 0.001). The SBF decrease recovered more slowly after the SDI (beat 7) than after the VM (veat 6). The SBF decrease was more pronounced in magnitude during the VM. The latency of the SSR appears spontaneously and at random in 57 of subjects during normal breathing but it appeared consistently during RB, SDI, and VM. The latency of SSR was longer during SB (1.7 +/- 0.7 s), RB (1.6 +/- 0.7 s) than SDI (0.7 +/- 0.5 s) and VM (0.8 +/- 0.9 s) (P > 0.050). Duration of the SSR was significantly longer in the SDI (around 7.8 +/- 2.4 s) and during the VM (8 +/- 2.5 s) as compared to normal breathing (6.3 +/- 1.0 s) and RB (6.4 +/- 1.5 s) (P < 0.009). CONCLUSIONS: SB and RB induce periodic modulation of sympathetic activity to skin blood vessels and sweat glands. SDI and VM produced a much greater activation of sympathetic skin activity than SB and RB. The increased SSR duration and the profound SBF decrease with SDI and VM as compared to SB or RB are consistent with this hypothesis. The latency of the SSR is much shorter with SDI and VM than with SB or RB. The most likely explanation is that the SSR, und

Efecto de la contracción muscular en la frecuencia cardiaca y en el flujo sanguÝneo cutßneo / Resultados preliminares. Effect of muscle contraction on heart rate and skin blood flow. Preliminary results

Evaluation of heart rate variability is an important tool to study several diseases. The most important tests include the variability of the heart rate as a function of time and as function of frequency, variability of blood pressure and pulsatile cutaneous blood flow (PCBF). We studied the effect of a sustained contraction of the quadriceps muscle on the instantaneous heart rate and pulsatile cutaneous blood flow in 10 healthy subjects. We measured the R-R interval and the instantaneous heart rate, in the time domain, 10 beats before the contraction, the R-R interval that coincided with the onset of the contraction, and the 30 R-R intervals after the beginning of the contraction. To measure the PCBF we used a photopletismograph designed for this purpose. We recorded the surface electromyographic activity (EMG) of the quadriceps muscle to determine the onset and end of the muscle contraction, and measured respiratory movements with a belt. We found an increase of the instantaneous heart rate at the first and second beats after the onset of the contraction. There was a decrease of the pulsatile cutaneous blood flow of the finger pad immediately after the contraction, which lasted for approximately eight beats. The findings support the idea of a central command and co-activation of the motor and sympathetic nervous systems. This efferent sympathetic activity seems to act not just on the contracting muscle but also on the heart and the cutaneous blood vessels of the extremities. These findings imply that it is quite likely that the sympathetic efferent effect has a supraspinal origin. This is a test that could be used to study cardiovascular control by the sympathetic nervous system.

Nuevas estrategias en el tratamiento farmacológico del tabaquismo / News strategies in the pharmacological treatment of tobac adiction

La adicción a la nicotina es uno de los problemas de salud pública más importantes en todos los países del mundo. Se piensa que el potencial adictivo de la nicotina es similar en intensidad al que genera la cocaína. Las tasas esperadas de muerte relacionadas al uso del tabaco para el 2020 será aproximadamente de 10 millones de personas. Las estrategias farmacológicas actuales para el tratamiento del tabaquismo incluyen la terapia sustitutiva por vías no inhalables, el bloqueo de los receptores nicotínicos y el desarrollo de una vacuna. Se ha demostrado que el bupropión es un antagonista de la nicotina. En los próximos años se tendrá una vacuna para uso clínico (Nic Vax ) que bloquea a la nicotina circulante antes que acceda al sistema nervioso central.