Anatomía microquirúrgica e irrigación arterial de la región uncal / Microsurgical anatomy and arterial irrigation of the uncal region

El objetivo de este trabajo fue realizar una revisión microquirúrgica de los principales ramos arteriales que otorgan irrigación a la región uncal, identificando sus principales variantes y sus relaciones anatómicas mas relevantes con las estructuras circundantes. Se estudiaron 20 hemisferios cerebrales con el sistema arterial perfundido con latex y colorante mediante disección microquirúrgica y bajo aumento con un rango de 3X a 40X. Se realizaron registros morfométricos de las principales estructuras. La irrigación de la región uncal del lóbulo temporal se establece principalmente por tres grupos de ramas uncales: las ramas uncales anteriores provenientes de la arteria temporopolar que es uno de las ramas colaterales que inicialmente se derivan de la arteria cerebral media en su segmento M1. Ramas uncales mediales provenientes de la arteria coroidea anterior en su trayecto cisternal. Ramas uncales posteriores provenientes de los segmentos P2A y P2P de la arteria cerebral posterior. La relevancia de la descripción vascular arterial de la región uncal radica en la aplicación del conocimiento de estas relaciones y variantes durante los diversos procedimientos diagnósticos y quirúrgicos del lóbulo temporal.

The objective of this work was realizing a microsurgical review of the main arterial ramus that distribute irrigation to the uncal region, identifying the most common variations and more relevant relationships with surrounding structures. Twenty (20) fixed human brain hemispheres were studied, with the arterial latex and red colorant perfusion technique for dissection under microscope magnification (3X-40X). Morphometric characterization and data were obtained of the structures studied. Arterial irrigation of the uncal region of the temporal lobe is established by three groups of uncal ramus: the anterior uncal rami, deriving from the temporopolar artery, which is one of the first branches of the middle cerebral artery in segment M1. The medial uncal rami, branches of the cisternal portion of the anterior choroidal artery. The posterior uncal rami, branches of the P2A and P2P segments of the posterior cerebral artery. The relevance of arterial vascular description of the uncus, results in the application of knowledge of the variations and relationships during the diagnostic and surgical procedures of the temporal lobe.

Hyperleptinemia as a prognostic factor for preeclampsia: a cohort study.

INTRODUCTION: Leptin is an adipokine which has a direct relationship to obesity. Our aim was to measure this hormone in pregnant women at three months intervals throughout their pregnancies to determine the serum value of those who developed preeclampsia. MATERIAL AND METHODS: We followed 19 women (median age 24.8 +/- 5.7 years) with pre-gestational Body Mass Index (BMI) less than 25 kg/m2, 21 (median age 26.1 +/- 4.6 years) with BMI higher than 25 kg/m2 and 16 (median age 30.9 +/- 5.8 years) with Gestational Diabetes Mellitus (GDM) (median age 30.9 +/- 5.8 years), recruited in the 1st trimester of pregnancy. Serum levels of leptin were measured with radioimmunoassay (RIA) technique. RESULTS: In the first trimester of pregnancy leptin levels showed statistically significant differences between normal weight and overweight-obese women (p < 0.001), diabetic women (p < 0.05) and the subgroup of preeclamptic women (p < 0.001). For those women with PGBMI > or = 40 kg/m2 and leptin > or = 40 ng/ml in the second trimester, the Odds Ratio (OR) to develop preeclampsia was of 47.95% CI (4.1-527.2). Analyzing leptin values with ROC curves, the greatest area under the curve (AUC) was for leptin in the second trimester (0.773, CI: 0.634-0.911). CONCLUSION: Women with morbid obesity (BMI > or = 40 kg/m2) had significantly higher levels of serum leptin (p < 0.01) and a value of 40 ng/ml of this hormone seems to be predictive of developing preeclampsia in this group of patients.

Diazepam blocks striatal lipid peroxidation and improves stereotyped activity in a rat model of acute stress.

In this work, the effect of a single dose of diazepam was tested on different markers of oxidative damage in the striatum of rats in an acute model of immobilization (restraint) stress. In addition, the locomotor activity was measured at the end of the restraint period. Immobilization was induced to animals for 24 hr, and then, lipid peroxidation, superoxide dismutase activity and content, and mitochondrial function were all estimated in striatal tissue samples. Corticosterone levels were measured in serum. Diazepam was given to rats as a pre-treatment (1 mg/kg, i.p.) 20 min. before the initiation of stress. Our results indicate that acute stress produced enhanced striatal levels of lipid peroxidation (73% above the control), decreased superoxide dismutase activity (54% below the control), reduced levels of mitochondrial function (35% below the control) and increased corticosterone serum levels (86% above the control). Pre-treatment of stressed rats with diazepam decreased the striatal lipid peroxidation levels (68% below the stress group) and improved mitochondrial function (18% above the stress group), but only mild preservation of superoxide dismutase activity was detected (17% above the stress group). In regard to the motor assessment, only the stereotyped activity was increased in the stress group with respect to control (46% above the control), and this effect was prevented by diazepam administration (30% below the stress group). The preventive actions of diazepam in this acute model of stress suggest that drugs exhibiting anxiolytic and antioxidant properties might be useful for the design of therapies against early acute phases of physic stress.

Early changes in oxidative stress markers in a rat model of acute stress: effect of l-carnitine on the striatum.

This work focuses on the effect of acute stress on different markers of oxidative stress and mitochondrial dysfunction in the rat striatum. In addition, the effect of a single dose of l-carnitine (l-CAR, 300 mg/kg, i.p.) was evaluated in these animals. Immobilization (restraint) stress was induced to rats for 24 hr. The levels of lipid peroxidation (LP) and mitochondrial function (MF), as well as the superoxide dismutase (SOD) activity and content and reduced glutathione (GSH) levels, were all measured in striatal samples of animals subjected to stress. Our results indicate that acute stress is able to increase the striatal LP and reduced the levels of MF, while significantly lowered the manganese superoxide dismutase (Mn-SOD) activity. No changes were observed in the total striatal content of SOD, nor in GSH levels, but serum corticosterone content was increased by stress. l-CAR exhibited partial protective effects on the immobilized group, reducing the striatal LP and recovering the striatal MF and Mn-SOD activity. Our results suggest that acute restraint stress brings an accurate model for early pro-oxidant responses that can be targeted by broad-spectrum antioxidants like l-CAR.

La desincronización interna como promotora de enfermedad y problemas de conducta / Internal desynchrony as promotor of disease and behavioral disturbance

Life on our planet is ruled by a temporary structure that governs our activities, our days and our calendars. In order to cope with a daily changing environment, organisms have developed adaptive strategies by exhibiting daily behavioral and physiological changes. Biological rhythms are properties conserved in all the levels of organization, from unicellular to prokaryotes to upper plants and mammals. A biological rhythm is defined as the recurrence of a biological phenomenon in regular intervals of time. Biological rhythms in behaviour and physiology are controled by an internal clock which synchronizes its oscillations to external time cues that have the capacity to adjust the clock's mechanism and keep it coupled to external fluctuations. The suprachiasmatic nucleus (SCN) of the hypothalamus in mammals is the master circadian clock which is mainly entrained by the light-dark cycle. The SCN transmits time signals to the brain and then to the whole body and by means of its time signals the SCN keeps a temporal order in diverse oscillations of the body and adjusted to the light-dark cycle. The correct temporal order enables an individual to adequate functioning in harmony with the external cycles. Biological rhythms have a hereditary character, thus its expression is genetically determined. All animals, plants, and probably all organism show some type of physiological rhythmic variation (metabolic rate, production of heat, flowering, etc.) that allow for the adaptation to a rhythmic environment. Biological rhythms enable individuals to anticipate and to be prepared to the demands of the prominent cyclic environmental changes, which are necessary for survival. Also, biological rhythms promote showing maximum levels of a physiological variable at the right moment when the environment requires a maximal response. In humans, an example of circadian rhythms is the sleep-wake cycle; simultaneously, a series of physiological changes are exhibited, also with circadian characteristics (close to 24 hours). Circadian oscillations are observed in the liberation of luteinizant hormone, in plasma cortisol, leptin, insulin, glucose and growth hormone just to mentions some examples. The SCN controls circadian rhythmicity via projections to the autonomic system and by controlling the hypothalamus-adenohipofisis-adrenal axis. In this way, the SCN transmits phase and period to the peripheral oscillators to maintain an internal synchrony. Modern life favors situations that oppose the time signals in the environment and promote conflicting signals to the SCN and its effectors. The consequence is that circadian oscillators uncouple from the master clock and from the external cycles leading to oscillations out of synchrony with the environment, which is known as internal desynchronization. The consequence is that physiological variables reach their peak expression at wrong moments according to environmental demands leading then to deficient responses and to disease in the long run. Also, levels of attention, learning and memory reach peak expression at wrong moments of the day leading individuals to exhibit a deficient performance at school or work. The disturbed sleep patterns promote fatigue and irritability, which difficult social interaction. Internal desynchronization results from transmeridional traveling for which people pass multiple hourly regions. This results in an abrupt change in the time schedule and a syndrome known as <>. Frequent travelers complain about difficulties to adjust their sleep-wake cycle to the new schedule, thus resulting in fatigue, increased sleepiness and reduced attention. Jet lag results from a loss of synchrony among biological rhythms and among diverse functions, which remain out of phase with the day-night cycle. This <> is the cause of general discomfort, decrement in the physical and mental performance, as well as irritability and depression. Frequently, gastrointestinal disorders are a by-product of food consumption at an unusual schedule. The state of internal desynchrony is transitory and depends on the number of time zones that were crossed; thus, adaptation to a new external cycle can take from four to seven days. Another example of internal desynchrony is observed in individuals exposed to work shifts or to nocturnal work schedules (night work). In such conditions, circadian fluctuations in behavioral, hormonal and metabolic parameters are observed but their temporary relation with the external cycles is modified. The internal synchrony is thus affected by troubled environmental signs, out of phase with the daily activities of the individual; among them are the hours of food intake, the exposure to light during resting hours, the low temperature of the night, and the forced activity when homeostatic processes indicate a need to rest. This internal desynchrony leads to gastrointestinal disorders, disturbed metabolic fluctuations, disturbed cardiovascular functions, altered menstrual cycle, sleep disorders, sleepiness, increase of work accidents, etc. Internal desynchrony is especially due to the fact that circadian fluctuations are influenced by daily external cycles, but also by homeostatic factors, and can suffer from additional disturbance by sleep deprivation. Despite years of night work experience, incapacity to adapt to night work may persist. Only a minority of shift workers achieve spontaneous adjustment of the rhythms of core body temperature, melatonin, cortisol, thyroid stimulating hormone, or prolactin secretion to shifts by nocturnal work. Therefore shift and night workers develop a propensity to smoke, drink alcoholic beverages and use stimulant products. After five years of shift or night work, health problems appear with a higher incidence than in the general population. The growing social demand of shift work makes it necessary to decide on the characteristics and forms of shifts to carry out, and up to now organizing such working schedules remaing a serious problem. The improvement of health services has increased life expectancies and thus the general population is becoming old and people survive more years. Older people ail from health and behavioral problems including a deterioration of the biological rhythms. Main alterations consist of a loss of expression of the circadian functions or a decrease of the amplitude of the rhythms, and instability of synchronization mechanisms day by day. All in all, this implies a decreased capacity of the clock to adjust to the solar day. The decreased efficacy of the aging biological clock is evident in the fragmented sleep patterns and the disturbed sleep/wake rhythms, characterized by short sleep episodes during the day and decreased sleep during the night. Some studies suggest that the disturbed circadian rhythms may be the cause of diverse diseases associated with the elderly. In conclusion, during the last 100 years we have changed our lifestyle so radically that we lack already a physiological design to adapt so quickly to modernity. We can state that our body is designed for a world that does not exist. In this article we present a review of the main alterations of the biological rhythms generated by the transmeridional trips, shift-work and aging, their behavioral and physiological consequences that lead to disease and poor mental performance. We also discuss possible strategies that need to be explored and that may help people to improve their quality of life and to prevent internal desynchrony.

La vida se rige por una estructura temporal que gobierna nuestras horas, nuestros días y nuestros calendarios. Como parte de la adaptación a los ciclos de tiempo que impone el planeta, todo organismo presenta ritmos en su actividad y fisiología. Los ritmos biológicos son una propiedad conservada en todos los niveles de organización, desde organismos unicelulares procariontes hasta plantas superiores y mamíferos. De ellos, los más sólidos son aquellos asociados a los ciclos externos por la alternancia del día y la noche y por la alternancia de las estaciones del año. Los ritmos biológicos fisiológicos y conductuales son procesos dependientes de un reloj interno capaz de ajustar sus oscilaciones a claves de tiempo externas que lo mantienen sincronizado a estas fluctuaciones externas. El núcleo supraquiasmático del hipotálamo (NSQ) es en los mamíferos el principal reloj circadiano y se sincroniza principalmente por el ciclo luz-oscuridad. El NSQ transmite señales de tiempo al cerebro y de ahí al resto del organismo, y por medio de estas señales de tiempo mantiene un orden temporal en diversas funciones del cuerpo y las mantiene ajustadas al ciclo luz-oscuridad. El correcto orden temporal interno permite un adecuado funcionamiento del individuo en armonía con el medio externo y le permite exhibir respuestas adecuadas a un ambiente cambiante y predecible. El estilo de vida del hombre moderno propicia situaciones que llevan a alteraciones de nuestros ritmos biológicos que causan una desadaptación temporal, que a su vez redunda en daños a la salud, ya que afecta tanto la fisiología como la forma en que organizamos nuestra conducta. Un ejemplo de ello son los viajes a través de múltiples regiones horarias. Estos cambios de horario bruscos provocan un síndrome conocido como jet-lag, que consiste en un conflicto transitorio entre el tiempo <> y el tiempo <>, lo cual se denomina <>. El jet-lag se define como un conjunto de síntomas causados por una alteración del patrón de sueño, y de la expresión de ritmos biológicos fuera de fase entre sí y fuera de fase con el ciclo del día y la noche. Esta es la causa del malestar general, el deterioro del desempeño mental y físico, así como de la irritabilidad y depresión. Son frecuentes también las alteraciones gastrointestinales, resultado del consumo de alimento en un horario inusual. Otro ejemplo de alteraciones en los ritmos circadianos se observa en los trabajadores con turnos rotatorios o en turnos nocturnos. En estas condiciones se produce un conflicto entre las señales temporales asociadas al ciclo diurno y que transmite el reloj con las actividades y alimentos del trabajador en turnos. De este esquema de trabajo resulta una reducción de las horas de sueño y una alteración de los ritmos circadianos, que llevan a una desincronización interna. Ésta, al igual que en el caso del jet-lag, redunda en un deterioro de las funciones mentales y de la capacidad de atención y memorización, que se asocian a irritabilidad y problemas emocionales. Además, se observan consecuencias en la salud con incremento en la incidencia de malestares gastrointestinales, enfermedades cardiovasculares, obesidad y diabetes. La mejoría en los servicios de salud ha incrementado las expectativas de vida, lo que entonces enfrenta a la humanidad a una población que logra sobrevivir muchos años de su vejez con los cambios de conducta y salud propios de su edad, entre los que se incluye un deterioro de los ritmos biológicos. En este trabajo presentamos una revisión de las principales alteraciones de los ritmos biológicos generadas por los viajes transmeridionales, la vejez y el trabajo en turnos. También discutimos la relevancia de una buena adaptación de los ritmos biológicos y las consecuencias conductuales y fisiológicas que por su alteración llevan a la enfermedad y a un desempeño mental deficiente. También sugerimos estrategias que necesitan ser exploradas y que podrían ayudar prevenir la desincronización interna para mejorar la calidad de vida.