Tuberculosis in renal transplant patients: The experience of a single center in Medellín-Colombia, 2005-2013 / Tuberculose em pacientes transplantados renais: experiência de um único centro em Medellín-Colômbia, 2005-2013

Introduction: Tuberculosis is a common opportunistic infection in renal transplant patients. Objective: To obtain a clinical and laboratory description of transplant patients diagnosed with tuberculosis and their response to treatment during a period ranging from 2005 to 2013 at the Pablo Tobón Uribe Hospital. Methods: Retrospective and descriptive study. Results: In 641 renal transplants, tuberculosis was confirmed in 12 cases. Of these, 25% had a history of acute rejection, and 50% had creatinine levels greater than 1.5 mg/dl prior to infection. The disease typically presented as pulmonary (50%) and disseminated (33.3%). The first phase of treatment consisted of 3 months of HZRE (isoniazid, pyrazinamide, rifampicin and ethambutol) in 75% of the cases and HZME (isoniazid, pyrazinamide, moxifloxacin and ethambutol) in 25% of the cases. During the second phase of the treatment, 75% of the cases received isoniazid and rifampicin, and 25% of the cases received isoniazid and ethambutol. The length of treatment varied between 6 and 18 months. In 41.7% of patients, hepatotoxicity was associated with the beginning of anti-tuberculosis therapy. During a year-long follow-up, renal function remained stable, and the mortality rate was 16.7%. Conclusion: Tuberculosis in the renal transplant population studied caused diverse nonspecific symptoms. Pulmonary and disseminated tuberculosis were the most frequent forms and required prolonged treatment. Antituberculosis medications had a high toxicity and mortality. This infection must be considered when patients present with a febrile syndrome of unknown origin, especially during the first year after renal transplant. .

Introdução: A tuberculose é uma infecção oportunista comum em pacientes transplantados renais. Objetivo: Oferecer uma descrição clínica e laboratorial de pacientes transplantados com diagnóstico de tuberculose e sua resposta ao tratamento durante o período entre 2005 e 2013 no Hospital Pablo Tobón Uribe. Métodos: Estudo retrospectivo descritivo. Resultados: Em 641 transplantes renais, a tuberculose foi confirmada em 12 pacientes. Destes, 25% tinham histórico de rejeição aguda e 50% apresentaram níveis de creatinina superiores a 1,5 mg/dl antes da infecção. A patologia geralmente se apresentava como pulmonar (50%) e disseminada (33,3%). A primeira fase do tratamento consistiu de três meses de HZRE (isoniazida, pirazinamida, rifampicina e etambutol) em 75% dos casos e HZME (isoniazida, pirazinamida, moxifloxacina e etambutol) em 25% dos pacientes. Durante a segunda fase do tratamento, 75% dos pacientes receberam isoniazida e rifampicina e 25% isoniazida e etambutol. A duração do tratamento variou entre seis e 18 meses. Em 41,7% dos pacientes, hepatotoxicidade foi associada ao início do tratamento da tuberculose. Durante o seguimento de um ano a função renal manteve-se estável e a taxa de mortalidade foi de 16,7%. Conclusão: A tuberculose foi responsável por diversos sintomas inespecíficos na população de transplantados renais estudada. Tuberculose pulmonar e disseminada foram as formas mais frequentes de acometimento e necessitaram de tratamento prolongado. Medicamentos contra a tuberculose apresentaram alta toxicidade e mortalidade. Esta infecção deve ser considerada quando o paciente apresenta síndrome febril de origem desconhecida, especialmente durante o primeiro ano após o transplante renal. .

Reduced hippocampal GABAergic function in Wistar audiogenic rats

Epilepsy is a neurological disorder associated with excitatory and inhibitory imbalance within the underlying neural network. This study evaluated inhibitory γ-amino-butyric acid (GABA)ergic modulation in the CA1 region of the hippocampus of male Wistar rats and Wistar audiogenic rats (aged 90 ± 3 days), a strain of inbred animals susceptible to audiogenic seizures. Field excitatory postsynaptic potentials and population spike complexes in response to Schaffer collateral fiber stimulation were recorded in hippocampal slices before and during application of picrotoxin (50 µM, 60 min), a GABA A antagonist, and the size of the population spike was quantified by measuring its amplitude and slope. In control audiogenic-resistant Wistar rats (N = 9), picrotoxin significantly increased both the amplitude of the population spike by 51 ± 19 percent and its maximum slope by 73 ± 21 percent. In contrast, in slices from Wistar audiogenic rats (N = 6), picrotoxin caused no statistically significant change in population spike amplitude (33 ± 46 percent) or slope (11 ± 29 percent). Data are reported as means ± SEM. This result indicates a functional reduction of GABAergic neurotransmission in hippocampal slices from Wistar audiogenic rats.

In vivo photorelease of GABA in the mouse cortex

Electrical stimulation has been used for more than 100 years in neuroscientific and biomedical research as a powerful tool for controlled perturbations of neural activity. Despite quickly driving neuronal activity, this technique presents some important limitations, such as the impossibility to activate or deactivate specific neuronal populations within a single stimulation site. This problem can be avoided by pharmacological methods based on the administration of receptor ligands able to cause specific changes in neuronal activity. However, intracerebral injections of neuroactive molecules inherently confound the dynamics of drug diffusion with receptor activation. Caged compounds have been proposed to circumvent this problem, for spatially and temporally controlled release of molecules. Caged compounds consist of a protecting group and a ligand made inactive by the bond between the two parts. By breaking this bond with light of an appropriate wavelength, the ligand recovers its activity within milliseconds. To test these compounds in vivo, we recorded local field potentials (LFPs) from the cerebral cortex of anesthetized female mice (CF1, 60-70 days, 20-30 g) before and after infusion with caged γ-amino-butyric-acid (GABA). After 30 min, we irradiated the cortical surface with pulses of blue light in order to photorelease the caged GABA and measure its effect on global brain activity. Laser pulses significantly and consistently decreased LFP power in four different frequency bands with a precision of few milliseconds (P < 0.000001); however, the inhibitory effects lasted several minutes (P < 0.0043). The technical difficulties and limitations of neurotransmitter photorelease are presented, and perspectives for future in vivo applications of the method are discussed.

Bases neurales del desarrollo de las funciones ejecutivas durante la infancia y adolescencia: una revisión / Neural basis of executive function development during childhood and adolescence: a review

Las funciones ejecutivas constituyen un controvertido constructo, bajo el cual se han agrupado diferentes procesos cognitivos asociadas al control consciente del pensamiento, comportamiento y afectividad. Gran parte de los mismos, comienzan su desarrollo en la infancia, culminando dicho proceso a fines de la adolescencia. A nivel anatómico, el funcionamiento ejecutivo (FE) ha sido vinculado a la actividad de la corteza prefrontal y la corteza cingulada, entre otras regiones cerebrales. El objetivo del presente artículo, es realizar una revisión de los cambios en la actividad cortical que han sido asociados a las mejoras en el FE durante la infancia y adolescencia. Para tal fin, se realizará una recopilación de diversos estudios con fMRI comparativos de la performance y actividad neuronal de infantes, adolescentes y adultos; durante la ejecución de tareas de FE. Se concluirá resaltando la necesidad de ampliar el número de estudios comparativos con tales características. Dichas investigaciones, podrían facilitar el diseño de estrategias preventivas y terapéuticas más específicas para el abordaje de las diferentes patologías asociadas al FE.

Executive functions is a controversial construct, under which are grouped different cognitive processes associated with conscious control of thought, behavior and emotion. Much of them, begin their development in childhood, finishing it in late adolescence. In the anatomical level, executive function (EF) has been linked to the activity of the prefrontal cortex and the cingulate cortex, among other brain regions. The purpose of this article is to review the changes in cortical activity that has been associated with improvements in EF during childhood and adolescence. To this goal, there will be a compilation of several fMRI studies that compare the performance and neuronal activity between infants, adolescents and adults during the performance of EF tasks. It will conclude by stressing the need to expand the number of comparative studies with such characteristics. Such research may facilitate the design of preventive and therapeutic strategies for addressing numerous pathologies associated with the FE.

Role of the caudal pressor area in the regulation of sympathetic vasomotor tone

It is well known that the ventrolateral medulla contains neurons involved in the tonic and reflex control of the cardiovascular system. Two regions within the ventrolateral medulla were initially identified: the rostral ventrolateral medulla (RVLM) and the caudal ventrolateral medulla (CVLM). Activation of the RVLM raises arterial blood pressure and sympathetic nerve activity, and activation of the CVLM causes opposite effects. The RVLM premotor neurons project directly to sympathetic preganglionic neurons and are involved in the maintenance of resting sympathetic vasomotor tone. A significant proportion of tonic activity in the RVLM sympathetic premotor neurons is driven by neurons located in a third region of the ventrolateral medulla denominated caudal pressor area (CPA). The CPA is a pressor region located at the extreme caudal part of the ventrolateral medulla that appears to have an important role controlling the activity of RVLM neurons. In this brief review, we will address the importance of the ventrolateral medulla neurons for the generation of resting sympathetic tone related to arterial blood pressure control focusing on two regions, the RVLM and the CPA.

Reflejo inhibitorio masetérico y condiciones clínicas estomatológicas en pacientes con parálisis cerebral / Inhibitory masseteric reflex and clinical stomatological conditions in cerebral palsy patients

Para contribuir al entendimiento de los mecanismos que acompañan las alteraciones masticatorias en pacientes con daño en el sistema nervioso central, se estudiaron en reflejo inhibitorio masetérico (RIM) y aspectos clínicos estomatológicos en 32 pacientes con diferentes tipos de parálisis cerebral (PC) en un rango de edad de 15 a 30 años. Se utilizó un modelo de regresión logística, la morfología refleja la distinción entre el tipo espástico y atetósico con una clasificación errónea de 31.35 por ciento (X2 =6.771, p=0.2382), con el conjunto de características cefalométricas, de la oclusión dental y de la articulación temporomandibular la distinción fue del 12.50 por ciento, (X2 =22.708, p=0.0453). A través del calculo de regresiones lineales, las condiciones estomatológicas y la edad explicaron las áreas inhibitorias faltantes (derecha e izquierda) y la razón de áreas (potenciación/inhibición) derecha con significancia estadística (p<0.05). Las variables clínicas con mayor poder de explicación respecto de los cambios reflejos fueron los contactos dentarios posteriores y anteriores (p<0.05). Se concluyó que los cambios en el tipo de PC no explican, por si mismos, los cambios del RIM y que estos últimos están asociados fundamentalmente con la disponibilidad de contactos dentarios. Se propone el registro del RIM con golpe al mentón para identificar la rapidez de la evolución de las secuelas masticatorias en pacientes con PC

Psiquiatria pavloviana: a mobilidade cortical e as neuroses experimentais / Pavlov's psychiatry: the cortical mobility and the experimental neuroses

Ivan Petrovitch Pavlov (1849/1936), descobridor dos reflexos condicionados, demonstrou com suas experiências em animais que o córtex é um órgäo em permanente mobilidade graças às propriedades de irradiaçäo e concentraçäo dos processos fundamentais da atividade nervosa superior, a excitaçäo e a inibiçäo. Demonstrou, ainda, que cada ponto excitado cria uma área de inibiçäo nas regiöes vizinhas (induçäo negativa) e cada ponto inibido gera o fenômeno inverso na cortiça cerebral (induçäo positiva). O conjunto desta atividade foi denominado de induçäo recíproca, segundo a qual há uma delimitaçäo exata e minuciosa dos pontos excitados e inibidos. Durante as experiências era freqüente o aparecimento de transtornos funcionais da atividade normal dos hemisférios cerebrais, dando origem a novas investigaçöes que culminaram com o importante capítulo das neuroses experimentais, distúrbios patológicos que aparecem quando ultrapassados os limites da capacidade de trabalho da cortiça cerebral dos animais