RESUMEN

The η→3π amplitude is sensitive to the quark mass difference m_{u}-m_{d} and offers a unique way to determine the quark mass ratio Q^{2}≡(m_{s}^{2}-m_{ud}^{2})/(m_{d}^{2}-m_{u}^{2}) from experiment. We calculate the amplitude dispersively and fit the KLOE Collaboration data on the charged mode, varying the subtraction constants in the range allowed by chiral perturbation theory. The parameter-free predictions obtained for the neutral Dalitz plot and the neutral-to-charged branching ratio are in excellent agreement with experiment. Our representation of the transition amplitude implies Q=22.0±0.7.

RESUMEN

Neuropathic pain is a disease of global burden. Its symptoms include spontaneous and stimulus-evoked painful sensations. Several maladaptive mechanisms underlying these symptoms have been elucidated in recent years: peripheral sensitization of nociception, abnormal excitability of afferent neurons, central sensitization comprising pronociceptive facilitation, disinhibition of nociception and central reorganization processes, and sympathetically maintained pain. This review aims to illustrate these pathophysiological principles, focussing on molecular and neurophysiological findings. Finally therapeutic options based on these findings are discussed.

Asunto(s)

Sensibilización del Sistema Nervioso Central/fisiología , Modelos Biológicos , Neuralgia , Humanos , Neuralgia/diagnóstico , Neuralgia/fisiopatología , Neuralgia/terapia , Células Receptoras Sensoriales/fisiología

RESUMEN

UNLABELLED: A triad of clinical symptoms, ie, autonomic, motor and sensory dysfunctions, characterizes complex regional pain syndromes (CRPS). Sensory dysfunction comprises sensory loss or spontaneous and stimulus-evoked pain. Furthermore, a disturbance in the body schema may occur. In the present study, patients with CRPS of the upper extremity and healthy controls estimated their hand sizes on the basis of expanded or compressed schematic drawings of hands. In patients with CRPS we found an impairment in accurate hand size estimation; patients estimated their own CRPS-affected hand to be larger than it actually was when measured objectively. Moreover, overestimation correlated significantly with disease duration, neglect score, and increase of two-point-discrimination-thresholds (TPDT) compared to the unaffected hand and to control subjects' estimations. In line with previous functional imaging studies in CRPS patients demonstrating changes in central somatotopic maps, we suggest an involvement of the central nervous system in this disruption of the body schema. Potential cortical areas may be the primary somatosensory and posterior parietal cortices, which have been proposed to play a critical role in integrating visuospatial information. PERSPECTIVE: CRPS patients perceive their affected hand to be bigger than it is. The magnitude of this overestimation correlates with disease duration, decreased tactile thresholds, and neglect-score. Suggesting a disrupted body schema as the source of this impairment, our findings corroborate the current assumption of a CNS involvement in CRPS.

Asunto(s)

Síndromes de Dolor Regional Complejo/complicaciones , Discriminación en Psicología/fisiología , Mano , Procesos Mentales/fisiología , Trastornos de la Destreza Motora/etiología , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Dimensión del Dolor , Umbral del Dolor , Autoimagen , Estadísticas no Paramétricas

RESUMEN

The use of functional brain imaging techniques offers the possibility of uncovering the cerebral processing of the human pain experience. In recent years, many imaging studies have focused on defining a network of brain structures involved in the processing of normal pain. Additionally, it has been shown that stimulus-evoked pain, which is a frequent symptom of neuropathic pain, causes distinct patterns of brain activation. In the present study, we quantitatively analyzed the data of previous functional imaging studies. Studies were thus collected by means of a MEDLINE query. A meta-analysis using the activation-likelihood estimation method was conducted to quantify the acquired results. We then used this data to summarize and compare the cerebral activations of (i) normal and stimulus-evoked pain, (ii) thermal and mechanical pain, (iii) different types of stimulus-evoked pain (hyperalgesia, allodynia), and (iv) clinical neuropathic and experimental pain. The results suggest the existence of distinct, although overlapping, neuronal networks related to these different types of pain.

Asunto(s)

Mapeo Encefálico/métodos , Encéfalo/fisiología , Hiperalgesia/fisiopatología , Dolor/fisiopatología , Humanos , Hiperalgesia/diagnóstico , Imagen por Resonancia Magnética/métodos , Dolor/diagnóstico , Tomografía de Emisión de Positrones/métodos

RESUMEN

In recent years reversible posterior leukoencephalopathy syndrome (RPLS) has become increasingly recognized. It represents an uncommon entity related to multiple pathologies, the most common being hypertensive crisis. The underlying pathophysiological mechanism is proposed to be one of vasogenic edema, without infarction; however, differentiation from cytotoxic edema can be crucial for therapeutic and clinical outcome. Diffusion-weighted magnetic resonance imaging (DWI), including calculation of the apparent diffusion coefficient (ADC), may be helpful for differentiation. We present a case of a healthy young woman in the 40th week of gestation, with no prior complications, who suddenly developed RPLS with vasogenic edema, which was differentiated with DWI and quantification of ADC. Follow-up cranial MRI showed complete remission. Pre-eclampsia could not be proven according to pathognomonic laboratory findings.

Asunto(s)

Edema Encefálico/patología , Encefalopatía Hipertensiva/patología , Complicaciones del Embarazo/patología , Adulto , Edema Encefálico/complicaciones , Diagnóstico Diferencial , Femenino , Humanos , Encefalopatía Hipertensiva/complicaciones , Imagen por Resonancia Magnética , Embarazo , Tercer Trimestre del Embarazo

RESUMEN

We report about a patient in whom transient tetraplegia with intact proprioception occurred immediately after infiltration of a facet joint at the C6 level guided by anatomical landmarks. After positioning the patient supine and applying atropine and oxygen, respiration and circulation were stable and all symptoms resolved within the next 30 min. The type of neurological pattern and the course of disease suggest an inadvertent injection into a cervical radicular artery that reinforces the anterior spinal artery. This complication is potentially serious and may be permanently disabling or life threatening. It should be considered by any clinician performing "blind" zygapophysial joint injections in the cervical spine. Using imaging guidance should help prevent this type of complication.

Asunto(s)

Anestésicos Locales/efectos adversos , Vértebras Cervicales/cirugía , Dolor de Cuello/tratamiento farmacológico , Cuadriplejía/inducido químicamente , Médula Espinal/efectos de los fármacos , Articulación Cigapofisaria/cirugía , Adulto , Arterias/lesiones , Atropina/uso terapéutico , Bradicardia/inducido químicamente , Bradicardia/fisiopatología , Vértebras Cervicales/fisiopatología , Enfermedad Crónica/terapia , Diagnóstico por Imagen/normas , Femenino , Humanos , Hipotensión/inducido químicamente , Hipotensión/fisiopatología , Enfermedad Iatrogénica/prevención & control , Inyecciones/efectos adversos , Lidocaína/efectos adversos , Monitoreo Fisiológico/normas , Antagonistas Muscarínicos/uso terapéutico , Dolor de Cuello/etiología , Dolor de Cuello/fisiopatología , Oxígeno/uso terapéutico , Complicaciones Posoperatorias/etiología , Complicaciones Posoperatorias/fisiopatología , Complicaciones Posoperatorias/prevención & control , Cuadriplejía/fisiopatología , Médula Espinal/irrigación sanguínea , Médula Espinal/fisiopatología , Articulación Cigapofisaria/inervación , Articulación Cigapofisaria/fisiopatología

RESUMEN

In paramedian caudal pontine infarctions, the medial lemniscus is often affected. This typically leads to dissociated sensory symptoms. We present a case in which a patient suffering from a bilateral caudal pontine infarction experienced a marked bilateral sensory disorder of the hands and distal arms.