Periaqueductal gray glutamatergic, cannabinoid and vanilloid receptor interplay in defensive behavior and aversive memory formation.

Stimulation of the midbrain periaqueductal gray matter (PAG) in humans elicits sensations of fear and impending terror, and mediates predator defensive responses in rodents. In rats, pharmacological stimulation of the dorsolateral portion of the PAG (dlPAG) with N-Methyl-d-Aspartate (NMDA) induces aversive conditioning that acts as an unconditioned stimulus (US). In the present work, we investigated the interplay between the vanilloid TRPV1 and cannabinoid CB1 receptors in the NMDA-dlPAG defensive response and in subsequent aversive learning. Rats were subjected to dlPAG NMDA infusion in an olfactory conditioned stimulus (CS) task allowing the evaluation of immediate and long-term defensive behavioral responses during CS presentation. The results indicated that an intermediate dose of NMDA (50 pmol) induced both immediate and long-term effects. A sub-effective dose of NMDA (25 pmol) was potentiated by the TRPV1 receptor agonist capsaicin (CAP, 1 nmol) and the CB1 receptor antagonist, AM251 (200 pmol). CAP (10 nmol) or the combination of CAP (1 nmol) and AM251 (200 pmol) induced long-term effects without increasing immediate defensive responses. The glutamate release inhibitor riluzole (2 or 4 nmol) and the AMPA/kainate receptor antagonist DNQX (2 or 4 nmol) potentiated the immediate effects but blocked the long-term effects. The results showed that immediate defensive responses rely on NMDA receptors, and aversive learning on the fine-tuning of TRPV1, CB1, metabotropic glutamate and AMPA receptors located in pre- and postsynaptic membranes. In conclusion, the activity of the dlPAG determines core affective aspects of aversive memory formation controlled by local TRPV1/CB1 balance.

Therapeutic alternatives in cutaneous T-cell lymphoma

Mycosis fungoides and Sézary syndrome, collectively referred to as cutaneous T-cell lymphoma, are non-Hodgkin's lymphomas that initially appear in the skin. Early-stage disease, limited to the skin, is best treated with sequential topical therapies such as topical nitrogen mustard, psoralen phototherapy (PUVA), or total-skin electron beam therapy. Photopheresis is the first line of therapy for the patient with erythroderma. Systemic therapy is generally reserved for patients with refractory disease and patients who initially present with extracutaneous involvement. Although there are several treatment options for cutaneous T-cell lymphoma, there have been few randomized comparative trials.

Morbimortalidad del paciente crónico: su evaluación en una unidad de medicina familiar

Con el propósito de determinar el comportamiento clínico de los pacientes poseedores de enfermedades crónicas, estudiamos 83 pacientes de la Unidad de Medicina Familiar del Hospital Jaime O. Pino del Instituto Dominicano de Seguros Sociales de San Pedro de Macorís, en un estudio observacional, retrospectivo, longitudinal y descriptivo a la vez, realizado desde julio de 1985 hasta julio de 1988. Las entidades nosológicas más relevantes fueron: la hipertensión arterial 57.73%, accidente vásculo-cerebrales 17.53%, insuficiencias cardiacas 12.37%, entre otras; a los 83 pacientes se les brindó 2,160 chequenos médicos. Se hospitalizaron 69 pacientes. Al momento de éstos ser egresados de la Unidad Médica Familiar, 98.5% se encontraban estables y 1.5% inestables. No hubo defunciones entre ellos. Los pacientes con edades por encima de 66 años fueron los más afectados 43%; entre 56-65 años 23%; 46-55 años 16%. 67 pacientes eran del sexo masculino y 16 sel sexo femenino. El programa de Medicina Familiar logra mantener estable el 98.5% de los pacientes crónicos, además de que disminuye sustancialmente los internamientos