RESUMEN
Magnetic fields generated by human and animal organs, such as the heart, brain and nervous system carry information useful for biological and medical purposes. These magnetic fields are most commonly detected using cryogenically-cooled superconducting magnetometers. Here we present the first detection of action potentials from an animal nerve using an optical atomic magnetometer. Using an optimal design we are able to achieve the sensitivity dominated by the quantum shot noise of light and quantum projection noise of atomic spins. Such sensitivity allows us to measure the nerve impulse with a miniature room-temperature sensor which is a critical advantage for biomedical applications. Positioning the sensor at a distance of a few millimeters from the nerve, corresponding to the distance between the skin and nerves in biological studies, we detect the magnetic field generated by an action potential of a frog sciatic nerve. From the magnetic field measurements we determine the activity of the nerve and the temporal shape of the nerve impulse. This work opens new ways towards implementing optical magnetometers as practical devices for medical diagnostics.
Asunto(s)
Anuros/fisiología , Magnetismo/instrumentación , Nervio Ciático/fisiología , Potenciales de Acción , Animales , Puntos CuánticosRESUMEN
Takotsubo cardiomyopathy (TTC) is an acute cardiac syndrome, characterized by transient left ventricular dysfunction often following a stressful event in post-menopausal women. Symptoms are indistinguishable from myocardial infarction. However, TTC patients do not have a culprit lesion on acute angiography, and regional akinesia is not limited to a single vascular territory. As opposed to other cardiomyopathies TTC is completely reversible, albeit with a 5% mortality rate as well as a 10% re-occurrence rate. This article summarizes the current knowledge about aetiology, diagnostics and treatment.
Asunto(s)
Cardiomiopatía de Takotsubo , Anciano , Diagnóstico Diferencial , Femenino , Humanos , Imagen por Resonancia Magnética , Persona de Mediana Edad , Imagen de Perfusión Miocárdica , Tomografía de Emisión de Positrones , Posmenopausia , Pronóstico , Cintigrafía , Estrés Psicológico/complicaciones , Cardiomiopatía de Takotsubo/diagnóstico , Cardiomiopatía de Takotsubo/diagnóstico por imagen , Cardiomiopatía de Takotsubo/etiología , Cardiomiopatía de Takotsubo/terapiaRESUMEN
The distribution and natural phytoplasma infection of Cacopsylla picta were investigated during a long-term field survey between 2002 and 2009 in commercial and abandoned apple proliferation-infected orchards throughout Germany, northern Switzerland, and eastern France. Comparable population dynamics were described for the different sites whereas considerable variations in the absolute population densities were observed among the years. Individual polymerase chain reaction (PCR) testing revealed, for each year, a rather stable natural infection rate with ?Candidatus Phytoplasma mali? of ?10% for overwintered adults of C. picta. Both genders were equally highly infected although more females were caught. The overall male/female ratio was 1:1.5. No direct correlation was found between the infection status of the orchard and the infection rate of overwintered C. picta. No influence of agricultural practices was seen. However, a relationship between the incidence of the disease and the vector population density became evident on a regional scale. Successful transmission of ?Ca. P. mali? occurred each year with overwintered individuals as well as with new adults. The transmission efficiency varied among the years within 8 to 45% for overwintered adults and 2 to 20% for individuals of the new generation. The load of single C. picta with ?Ca. P. mali? was determined by quantitative real-time PCR. High phytoplasma titers were measured in overwintered adults already at their first appearance in the orchards after remigration from their overwintering hosts. Thus, the data indicate the transmission of the disease on a regional scale by remigrant adults of C. picta and at a local scale within the same season by emigrant adults which developed on infected plants.
Asunto(s)
Hemípteros/microbiología , Insectos Vectores/microbiología , Malus/crecimiento & desarrollo , Phytoplasma/fisiología , Enfermedades de las Plantas/estadística & datos numéricos , Animales , Femenino , Francia , Alemania , Incidencia , Masculino , Malus/microbiología , Enfermedades de las Plantas/microbiología , Densidad de Población , Dinámica Poblacional , Estaciones del Año , SuizaRESUMEN
Pretreatment with salicylic acid (SA), an inducer of plant disease resistance, enhanced the capacity of parsley cells for the induction of a rapid K(+)/pH response and the subsequent coumarin (phytoalexin) secretion. In SA-primed cells, a low elicitor dose induced these two responses to a similar extent as did a high elicitor dose in non-primed cells. These observations suggest that the SA-mediated augmentation of the early K(+)/pH response may contribute to the enhancement of subsequent coumarin secretion. As the amphotericin B-induced K(+)/pH response was not enhanced in SA-primed cells, it is concluded that signaling components that are improved by priming are located between elicitor signal perception and the plasma membrane transporters mediating the K(+)/pH response.