RESUMO
The results from various studies have indicated possible functional relationships between crayfish electroretinogram (ERG) rhythmic amplitude changes and the serotonergic pathways projecting from the central brain through the optic neuropils to the eye, but to date, this functional interaction has not been proven. Here, in a set of experiments using an isolated eyestalk-brain preparation, we investigated whether there is a circadian input from the brain to retina that regulates this rhythm. We sought to determine whether the protocerebral bridge (PB) stimulation affects the ERG amplitude in accordance with the zeitgeber time (ZT) and whether 5-HT modulates the associate input. Our results showed that photic stimulation of retina produced changes in both the amplitude and the frequency of spontaneous electrical activity in the protocerebral neuropils. In addition, electrical stimulation of the medial protocerebrum, particularly the PB, produced statistically significant changes in the ERG that depended on both the time of day and the level of serotonin. This suggests that pathways between retina and PB seem to be serotonergic.
Assuntos
Astacoidea/fisiologia , Encéfalo/fisiologia , Vias Neurais/fisiologia , Retina/fisiologia , Serotonina/metabolismo , Animais , Ritmo Circadiano/fisiologia , Eletrorretinografia , Neurópilo/fisiologia , Técnicas de Cultura de Órgãos , Técnicas de Patch-Clamp , Estimulação LuminosaRESUMO
UNLABELLED: Syncope is a common symptom among older adults. Its aetiologic diagnosis is mainly clinical, but when it has an unknown origin, complementary studies are necessary. We present the experience of a single center in diagnosing Unknown Origin Syncope (UOS). METHODS: We performed a transversal retrolective study to assess the different tests done to patients studied because of USO. RESULTS: The mean age of the older group was 77.6 +/- 6.9 years. The 24-hour Hotter were abnormal in 77.9% of patients, but diagnostic in only 16.3%. Age older than 65 years was associated with a 1.9 increase (CI 95% 0.9-4) in the possibilities of having a diagnosis, while age lesser than 65 was associated with a 0.5 risk CI 95% 0.2-1.08 of having a diagnosis. The 48-hour holter showed similar results. Older age was associated with a 1.69 OR, CI 95% 0.6-4.4 to have a positive Tilt test (91% of older patients). They had mainly the vasodepressor variety of neurally-mediated syncope. (57.1% Vs 40.1%, p = 0.01). Of the 6 electrophysiologic studies performed in people older than 65 years, 3 where diagnostic (50% Vs 33.3%, p = 0.6). CONCLUSIONS: Complimentary tests in people elder than 65 years are diagnostic in a higher proportion than in their younger counterparts. Nevertheless there is a higher risk of false-positive results, so tests such as head-up tilt test should be more carefully interpreted.
Assuntos
Síncope/etiologia , Idoso , Estudos Transversais , Feminino , Hospitais Universitários , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Síncope/diagnósticoRESUMO
Syncope is a common symptom among older adults. Its aetiologic diagnosis is mainly clinical, but when it has an unknown origin, complementary studies are necessary. We present the experience of a single center in diagnosing Unknown Origin Syncope (UOS). METHODS: We performed a transversal retrolective study to assess the different tests done to patients studied because of USO. RESULTS: The mean age of the older group was 77.6 +/- 6.9 years. The 24-hour Hotter were abnormal in 77.9% of patients, but diagnostic in only 16.3%. Age older than 65 years was associated with a 1.9 increase (CI 95% 0.9-4) in the possibilities of having a diagnosis, while age lesser than 65 was associated with a 0.5 risk CI 95% 0.2-1.08 of having a diagnosis. The 48-hour holter showed similar results. Older age was associated with a 1.69 OR, CI 95% 0.6-4.4 to have a positive Tilt test (91% of older patients). They had mainly the vasodepressor variety of neurally-mediated syncope. (57.1% Vs 40.1%, p = 0.01). Of the 6 electrophysiologic studies performed in people older than 65 years, 3 where diagnostic (50% Vs 33.3%, p = 0.6). CONCLUSIONS: Complimentary tests in people elder than 65 years are diagnostic in a higher proportion than in their younger counterparts. Nevertheless there is a higher risk of false-positive results, so tests such as head-up tilt test should be more carefully interpreted.
Assuntos
Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Síncope , Estudos Transversais , Hospitais Universitários , Estudos Retrospectivos , SíncopeRESUMO
OBJECTIVE: Out-of-hospital cardiac arrest is one of the leading causes of death in Mexico, but many survival and prognostic factors are unknown. The aim of this study was to assess out-of-hospital cardiac arrest in a Mexican city. METHODS: This was a prospective, cohort study that evaluated the records of the major ambulance services in the city of Queretaro, Mexico. Means, standard deviation, and percentages for the categorical variables were obtained. Logistic regression was performed to determine the effects between interventions, times, and return of spontaneous circulation (ROSC). RESULTS: For an 11-month period, 148 out-of-hospital cardiac arrest cases were recorded. The mean age of the victims was 54 +/- 22.6 years and 90 (65.3%) were males. Forty-nine cases were related to cardiac disease, 46 to other disease, 27 to trauma, 18 to terminal illnesses, and three to drowning. Twelve (8.6%) patients had a pulse upon hospital arrival, but none survived to discharge. No victims were defibrillated prior to ambulance arrival. The collapse-assessment interval was 22.5 +/- 19:1 minutes, the mean value for the ambulance response times was 13:6 +/-10:4 minutes. Basic emergency medical technicians applied chest compressions to 40 victims (27.2%), controlled the airway in 32 (21.8%), and defibrillated seven (4.8%). Chest compressions and airway control showed an OR of 8 and 12 respectively for ROSC. CONCLUSIONS: The poor survival rate in this study emphasizes the need to improve efforts in provider training and public education. Authorities must promote actions to enhance prehospital emergency services capabilities, shorten response times, and provide community education to increase the chances of survival for out-of-hospital cardiac arrest victims in Mexico.
Assuntos
Serviços Médicos de Emergência/métodos , Infarto do Miocárdio/terapia , População Urbana , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Estudos de Coortes , Humanos , Lactente , México , Pessoa de Meia-Idade , Avaliação de Resultados em Cuidados de Saúde , Estudos Prospectivos , Adulto JovemRESUMO
Adult crayfish exhibit a variety of overt circadian rhythms. However, the physiological mechanisms underlying the overt rhythms are controversial. Research has centered on two overt rhythms: the motor activity and the retinal sensitivity rhythms of the genus Procambarus. The present work reviews various studies undertaken to localize pacemakers and mechanisms of entrainment responsible for these two rhythms in adult organisms of this crustacean decapod. It also describes an ontogenetic approach to the problem by means of behavioral, electrophysiological, and neurochemical experiments. The results of this approach confirm previous models proposed for adult crayfish, based on a number of circadian pacemakers distributed in the central nervous system. However, the coupling of rhythmicity between these independent oscillators might be complex and dependent on the interaction between serotonin (5-HT), light, and the crustacean hyperglycemic hormone (CHH). The latter compound has, up until now, not been considered as an agent in the genesis and synchronization of the retinal sensitivity rhythm.