[Electroencephalographic findings in preterm neonates]. / Hallazgos electroencefalográficos en recién nacidos pretérmino.

Background: The electroencephalogram (EEG) in the newborn period is highly superior to the clinical exam in the detection and prognosis of brain dysfunctions, since it allows continuous functional documentation of the brain at the patient's bedside in a non-invasive way. However, there is still some disagreement about these findings. Objective: To describe the electroencephalographic findings in newborns with a history of prematurity. Material and methods: Cross-sectional, descriptive, retrospective study. The inclusion criteria were: newborns with a history of prematurity, regardless of gender, who underwent an EEG from June 2017 to June 2021. Patients with incomplete electroencephalographic records or clinical records without complete data were excluded; patients using sedatives (thiopental, fentanyl, midazolam, diazepam) were eliminated from the study. Results: 107 patients (37 women and 70 men) with a history of prematurity were included, with a mean gestational age at birth of 30.9 WOG ± 3.25. Electroencephalographic findings were normal in 40%, abnormal in 32%, and immature in 28%. The most frequent abnormal finding was focal paroxysmal activity in 86%. 93.4% of the participants presented comorbidities, the most frequent being neurological. Conclusion: Preterm neonates are at high risk of neurologic sequelae, and EEG is a sensitive method for assessing neuromotor and cognitive prognosis. In our study population, one-third had abnormal findings. Early postnatal screening is helpful, but additional records are usually needed to detect high-risk newborns. It would be important to continue studying this line of research in pediatrics.

Introducción: el electroencefalograma (EEG) en el periodo neonatal es muy superior al examen clínico en la detección y pronóstico de disfunciones cerebrales, pues permite hacer una documentación funcional cerebral continua y no invasiva junto a la cama del paciente. Sin embargo, todavía hay cierto desacuerdo sobre estos hallazgos. Objetivo: describir los hallazgos electroencefalográficos en recién nacidos (RN) con antecedente de prematurez. Material y métodos: estudio transversal, descriptivo, retrospectivo. Los criterios de inclusión fueron: RN con antecedente de prematurez, sin distinción de género, a quienes se les haya hecho un EEG de junio de 2017 a junio de 2021. Se excluyeron pacientes con registro electroencefalográfico incompleto o expediente clínico sin datos completos; se eliminaron del estudio pacientes que usaran sedantes (tiopental, fentanilo, midazolam, diazepam). Resultados: se incluyeron 107 pacientes (37 mujeres y 70 hombres) con antecedente de prematurez, con una edad gestacional media al nacer de 30.9 SDG ± 3.25. Los hallazgos de EEG fueron normales en 40%, anormales en 32% e inmaduros en 28%. El hallazgo anormal más frecuente fue la actividad paroxística focal en 86%. El 93.4% de los participantes presentaban comorbilidades, sobre todo neurológicas. Conclusión: los RN pretérmino tienen un alto riesgo de secuelas neurológicas y el EEG es un método sensible para evaluar el pronóstico neuromotor y cognitivo. En nuestra población un tercio tuvo hallazgos anormales. El rastreo posnatal temprano es útil, pero se necesitan registros adicionales para detectar RN de alto riesgo. Es importante continuar esta línea de investigación en pediatría.

Connectomic analysis of the Drosophila lateral neuron clock cells reveals the synaptic basis of functional pacemaker classes.

The circadian clock orchestrates daily changes in physiology and behavior to ensure internal temporal order and optimal timing across the day. In animals, a central brain clock coordinates circadian rhythms throughout the body and is characterized by a remarkable robustness that depends on synaptic connections between constituent neurons. The clock neuron network of Drosophila, which shares network motifs with clock networks in the mammalian brain yet is built of many fewer neurons, offers a powerful model for understanding the network properties of circadian timekeeping. Here, we report an assessment of synaptic connectivity within a clock network, focusing on the critical lateral neuron (LN) clock neuron classes within the Janelia hemibrain dataset. Our results reveal that previously identified anatomical and functional subclasses of LNs represent distinct connectomic types. Moreover, we identify a small number of non-clock cell subtypes representing highly synaptically coupled nodes within the clock neuron network. This suggests that neurons lacking molecular timekeeping likely play integral roles within the circadian timekeeping network. To our knowledge, this represents the first comprehensive connectomic analysis of a circadian neuronal network.

Most organisms on Earth possess an internal timekeeping system which ensures that bodily processes such as sleep, wakefulness or digestion take place at the right time. These precise daily rhythms are kept in check by a master clock in the brain. There, thousands of neurons ­ some of which carrying an internal 'molecular clock' ­ connect to each other through structures known as synapses. Exactly how the resulting network is organised to support circadian timekeeping remains unclear. To explore this question, Shafer, Gutierrez et al. focused on fruit flies, as recent efforts have systematically mapped every neuron and synaptic connection in the brain of this model organism. Analysing available data from the hemibrain connectome project at Janelia revealed that that the neurons with the most important timekeeping roles were in fact forming the fewest synapses within the network. In addition, neurons without internal molecular clocks mediated strong synaptic connections between those that did, suggesting that 'clockless' cells still play an integral role in circadian timekeeping. With this research, Shafer, Gutierrez et al. provide unexpected insights into the organisation of the master body clock. Better understanding the networks that underpin circadian rhythms will help to grasp how and why these are disrupted in obesity, depression and Alzheimer's disease.

Aggression in Drosophila.

Aggression is used by essentially all species of animals to gain access to desired resources, including territory, food, and potential mates: Fruit flies are no exception. In Drosophila, both males and females compete in same sex fights for resources, but only males establish hierarchical relationships. Many investigators now study aggression using the fruit fly model, mainly because (a) aggression in fruit flies is a quantifiable well-defined and easily evoked behavior; (b) powerful genetic methods allow investigators to manipulate genes of interest at any place or time during embryonic, larval, pupal or adult life, and while flies are behaving; (c) the growth of the relatively new field of optogenetics makes physiological studies possible at single neuron levels despite the small sizes of neurons and other types of cells in fly brains; and (d) the rearing of fly stocks with their short generation times and limited growth space requirements can easily be performed at relatively low cost in most laboratories. This review begins with an examination of the behavior, both from a historical perspective and then from the birth of the "modern" era of studies of aggression in fruit flies including its quantitative analysis. The review continues with examinations of the roles of genes, neurotransmitters and neurohormones, peptides, nutritional and metabolic status, and surface cuticular hydrocarbons in the initiation and maintenance of aggression. It concludes with suggestions for future studies with this important model system.

Single serotonergic neurons that modulate aggression in Drosophila.

Monoamine serotonin (5HT) has been linked to aggression for many years across species. However, elaboration of the neurochemical pathways that govern aggression has proven difficult because monoaminergic neurons also regulate other behaviors. There are approximately 100 serotonergic neurons in the Drosophila nervous system, and they influence sleep, circadian rhythms, memory, and courtship. In the Drosophila model of aggression, the acute shut down of the entire serotonergic system yields flies that fight less, whereas induced activation of 5HT neurons promotes aggression. Using intersectional genetics, we restricted the population of 5HT neurons that can be reproducibly manipulated to identify those that modulate aggression. Although similar approaches were used recently to find aggression-modulating dopaminergic and Fru(M)-positive peptidergic neurons, the downstream anatomical targets of the neurons that make up aggression-controlling circuits remain poorly understood. Here, we identified a symmetrical pair of serotonergic PLP neurons that are necessary for the proper escalation of aggression. Silencing these neurons reduced aggression in male flies, and activating them increased aggression in male flies. GFP reconstitution across synaptic partners (GRASP) analyses suggest that 5HT-PLP neurons form contacts with 5HT1A receptor-expressing neurons in two distinct anatomical regions of the brain. Activation of these 5HT1A receptor-expressing neurons, in turn, caused reductions in aggression. Our studies, therefore, suggest that aggression may be held in check, at least in part, by inhibitory input from 5HT1A receptor-bearing neurons, which can be released by activation of the 5HT-PLP neurons.

Pheromonal and behavioral cues trigger male-to-female aggression in Drosophila.

Appropriate displays of aggression rely on the ability to recognize potential competitors. As in most species, Drosophila males fight with other males and do not attack females. In insects, sex recognition is strongly dependent on chemosensory communication, mediated by cuticular hydrocarbons acting as pheromones. While the roles of chemical and other sensory cues in stimulating male to female courtship have been well characterized in Drosophila, the signals that elicit aggression remain unclear. Here we show that when female pheromones or behavior are masculinized, males recognize females as competitors and switch from courtship to aggression. To masculinize female pheromones, a transgene carrying dsRNA for the sex determination factor transformer (traIR) was targeted to the pheromone producing cells, the oenocytes. Shortly after copulation males attacked these females, indicating that pheromonal cues can override other sensory cues. Surprisingly, masculinization of female behavior by targeting traIR to the nervous system in an otherwise normal female also was sufficient to trigger male aggression. Simultaneous masculinization of both pheromones and behavior induced a complete switch in the normal male response to a female. Control males now fought rather than copulated with these females. In a reciprocal experiment, feminization of the oenocytes and nervous system in males by expression of transformer (traF) elicited high levels of courtship and little or no aggression from control males. Finally, when confronted with flies devoid of pheromones, control males attacked male but not female opponents, suggesting that aggression is not a default behavior in the absence of pheromonal cues. Thus, our results show that masculinization of either pheromones or behavior in females is sufficient to trigger male-to-female aggression. Moreover, by manipulating both the pheromonal profile and the fighting patterns displayed by the opponent, male behavioral responses towards males and females can be completely reversed. Therefore, both pheromonal and behavioral cues are used by Drosophila males in recognizing a conspecific as a competitor.

The Drosophila circadian network is a seasonal timer.

Previous work in Drosophila has defined two populations of circadian brain neurons, morning cells (M-cells) and evening cells (E-cells), both of which keep circadian time and regulate morning and evening activity, respectively. It has long been speculated that a multiple oscillator circadian network in animals underlies the behavioral and physiological pattern variability caused by seasonal fluctuations of photoperiod. We have manipulated separately the circadian photoentrainment pathway within E- and M-cells and show that E-cells process light information and function as master clocks in the presence of light. M-cells in contrast need darkness to cycle autonomously and dominate the network. The results indicate that the network switches control between these two centers as a function of photoperiod. Together with the different entraining properties of the two clock centers, the results suggest that the functional organization of the network underlies the behavioral adjustment to variations in daylength and season.

Impaired clock output by altered connectivity in the circadian network.

Substantial progress has been made in elucidating the molecular processes that impart a temporal control to physiology and behavior in most eukaryotes. In Drosophila, dorsal and ventral neuronal networks act in concert to convey rhythmicity. Recently, the hierarchical organization among the different circadian clusters has been addressed, but how molecular oscillations translate into rhythmic behavior remains unclear. The small ventral lateral neurons can synchronize certain dorsal oscillators likely through the release of pigment dispersing factor (PDF), a neuropeptide central to the control of rhythmic rest-activity cycles. In the present study, we have taken advantage of flies exhibiting a distinctive arrhythmic phenotype due to mutation of the potassium channel slowpoke (slo) to examine the relevance of specific neuronal populations involved in the circadian control of behavior. We show that altered neuronal function associated with the null mutation specifically impaired PDF accumulation in the dorsal protocerebrum and, in turn, desynchronized molecular oscillations in the dorsal clusters. However, molecular oscillations in the small ventral lateral neurons are properly running in the null mutant, indicating that slo is acting downstream of these core pacemaker cells, most likely in the output pathway. Surprisingly, disrupted PDF signaling by slo dysfunction directly affects the structure of the underlying circuit. Our observations demonstrate that subtle structural changes within the circadian network are responsible for behavioral arrhythmicity.

Alteraciones neurotológicas en la esclerosis múltiple / Neurotological distrurbances in multiples sclerosis

La esclerosis múltiple es una enfermedad desmielinizante del sistema nervioso, de etiología aún desconocida. La afección del VIII par craneal es frecuente, por ello se realizó una investigación en 20 pacientes con diagnóstico de certeza de esclerosis múltiple, con manifestaciones otoneurológicas, los cuales fueron sometidos a un examen neurológico, a determinación de inmunoglobulina G en el líquido cefalorraquídeo, audiometría tonal, electronistagmografía, potenciales evocados auditivos del tallo cerebral y resonancia magnética nuclear; con la finalidad de conocer la alteración otoneurológica mas frecuente y el impacto de los estudios paraclínicos en la esclerosis múltiple. El vértigo (90 por ciento) fue el dato mas importante. Los potenciales evocados como la resonancia magnética demostraron la evidencia de lesiones, pero no se pudo establecer una relación entre ambos estudios

Evaluación de la audición en lactantes con alto riesgo con potenciales evocados auditivos del tallo cerebral / Evaluation of hearing in the high-risk infant with brain-stem auditory evoked potentials

Se estudiaron cuarenta niños entre 1 y 6 meses de edad, 20 con factores de alto riesgo para desarrollar hipoacusia neurosensorial adquirida postnatalmente: prematurez, hipoxia, hiperbilirrubinemia, meningitis y la utilización de aminoglucósidos; y 20 lactantes sir riesgo, que conformaron el grupo control. En ambos grupos se valoró la audición mediante potenciales evocados auditivos del tallo cerebral, con la finalidad de conocer la repercusión de estos antecedentes en la capacidad auditiva. Se midió especificamente la latencia de la onda V para definir la integridad y la madurez de la vía auditiva. Se encontró una diferencia estadísticamente significativa de p<0.01 entre el grupo de alto riesgo (6.55 +/- 0.46 en el oído derecho y 6.63 +/- 0.43 en el oído izquierdo) y el grupo control (6.31 +/- 0.29 en el oído derecho y 6.35 +/- 0.08 en el oído izquierdo). Además la administración de aminoglucósidos (80 por ciento) se relacionó con mayor frecuencia con alteraciones en los potenciales evocados. Consideramos que los potenciales evocados auditivos del tallo cerebral son necesarios en la evaluación de los infantes con alto riesgo

Rinosinusitis alérgica crónica compleja del Distrito Federal / Complex chronical allergical rhinosinusitis of the Federal District, Mexico

La rinosinusitis crónica es quizá el desorden rinosinusal que se presenta con mayor frecuencia en la población de la ciudad de México, el cual es producido por diversos factores, tales como estados anormales de las vías aéreas superiores, factores alérgicos, climáticos y de la contaminación que afectan directamente las vías respiratorias de acceso. En el presente trabajo, se realizó un estudio retrospectivo en 60 pacientes escogidos al azar que llegaron a la consulta privada con diagnóstico de rinitis alérgica pura; establecida por alergólogos, otorrinolaringólogos, pediatras y médicos generales. De estos pacientes, 52 son residentes de México, Distrito Federal y 8 de otras partes de la república, los cuales no había evolucionado favorablemente con el tratamiento para la rinitis alérgica pura. La finalidad de esta investigación es la de conocer la causa de la ausencia de mejoría en estos pacientes al tratamiento de rinitis alérgica. Se encontró que dichos pacientes presentaron varios factores predisponentes que pueden desencadenar un síndrome que actualmente debe reconocerse como rinosinusitis alérgica crónica compleja propia de las ciudades con altos índices de contaminación.

Antecedentes históricos de la hipofisectomía / Historical background of hypophysectomy

La cirugía hopofisaria comenzó a finales del siglo XIX, la aproximación del seno esfenoidal por la vía intranasal constituyó uno de los primeros métodos intracraneanos para la resección de los tumores hipofisarios, sin embargo, tuvo el inconveniente de comprometer la funcionalidad y la estética nasal; por lo que Killian introduce la técnica transesfenoidal por vía submucosa nasal, que sería mejorada por Hirschen 1909. Cushing en 1914 describe el abordaje transesfenoidal por la incisión sublabial para poder resecar el septum y permitir así una ruta transnasal media hacia el esfenoides y la glándula hipófisis, la cual tuvo gran aceptación por su baja morbi-mortalidad. Con el progreso de la medicina operatoria en los ultimos 30 años y con la introducción del microscopio quirúrgico por Hardy y Guiot. Se presenta el concepto de la resección selectiva de microadenomas hipofisarios por vía transesfenoidal. En las últimas 2 décadas, Kern ha demostrado la utilidad del abordaje transeptal-trasesfenoidal con el método de la vía maxila-premaxila. Por su parte, los doctores mexicanos: Gutiérrez Marcos, Azuara Pliego y Quezada González entre otros, destacan la vía transeptal-transesfenoidal como el método de elección para la resección de los microadenomas hipofisarios.(AU)

Antecedentes históricos de la hipofisectomía / Historical antecedents of hypophysectomy

La cirugía hopofisaria comenzó a finales del siglo XIX, la aproximación del seno esfenoidal por la vía intranasal constituyó uno de los primeros métodos intracraneanos para la resección de los tumores hipofisarios, sin embargo, tuvo el inconveniente de comprometer la funcionalidad y la estética nasal; por lo que Killian introduce la técnica transesfenoidal por vía submucosa nasal, que sería mejorada por Hirschen 1909. Cushing en 1914 describe el abordaje transesfenoidal por la incisión sublabial para poder resecar el septum y permitir así una ruta transnasal media hacia el esfenoides y la glándula hipófisis, la cual tuvo gran aceptación por su baja morbi-mortalidad. Con el progreso de la medicina operatoria en los ultimos 30 años y con la introducción del microscopio quirúrgico por Hardy y Guiot. Se presenta el concepto de la resección selectiva de microadenomas hipofisarios por vía transesfenoidal. En las últimas 2 décadas, Kern ha demostrado la utilidad del abordaje transeptal-trasesfenoidal con el método de la vía maxila-premaxila. Por su parte, los doctores mexicanos: Gutiérrez Marcos, Azuara Pliego y Quezada González entre otros, destacan la vía transeptal-transesfenoidal como el método de elección para la resección de los microadenomas hipofisarios.