Life at extreme elevations on Atacama volcanoes: the closest thing to Mars on Earth?

Here we describe recent breakthroughs in our understanding of microbial life in dry volcanic tephra ("soil") that covers much of the surface area of the highest elevation volcanoes on Earth. Dry tephra above 6000 m.a.s.l. is perhaps the best Earth analog for the surface of Mars because these "soils" are acidic, extremely oligotrophic, exposed to a thin atmosphere, high UV fluxes, and extreme temperature fluctuations across the freezing point. The simple microbial communities found in these extreme sites have among the lowest alpha diversity of any known earthly ecosystem and contain bacteria and eukaryotes that are uniquely adapted to these extreme conditions. The most abundant eukaryotic organism across the highest elevation sites is a Naganishia species that is metabolically versatile, can withstand high levels of UV radiation and can grow at sub-zero temperatures, and during extreme diurnal freeze-thaw cycles (e.g. - 10 to + 30 °C). The most abundant bacterial phylotype at the highest dry sites sampled (6330 m.a.s.l. on Volcán Llullaillaco) belongs to the enigmatic B12-WMSP1 clade which is related to the Ktedonobacter/Thermosporothrix clade that includes versatile organisms with the largest known bacterial genomes. Close relatives of B12-WMSP1 are also found in fumarolic soils on Volcán Socompa and in oligotrophic, fumarolic caves on Mt. Erebus in Antarctica. In contrast to the extremely low diversity of dry tephra, fumaroles found at over 6000 m.a.s.l. on Volcán Socompa support very diverse microbial communities with alpha diversity levels rivalling those of low elevation temperate soils. Overall, the high-elevation biome of the Atacama region provides perhaps the best "natural experiment" in which to study microbial life in both its most extreme setting (dry tephra) and in one of its least extreme settings (fumarolic soils).

Microbial Communities of High-Elevation Fumaroles, Penitentes, and Dry Tephra "Soils" of the Puna de Atacama Volcanic Zone.

The aim of this study was to understand the spatial distribution of microbial communities (18S and 16S rRNA genes) across one of the harshest terrestrial landscapes on Earth. We carried out Illumina sequencing using samples from two expeditions to the high slopes (up to 6050 m.a.s.l.) of Volcán Socompa and Llullaillaco to describe the microbial communities associated with the extremely dry tephra compared to areas that receive water from fumaroles and ice fields made up of nieves penitentes. There were strong spatial patterns relative to these landscape features with the most diverse (alpha diversity) communities being associated with fumaroles. Penitentes did not significantly increase alpha diversity compared to dry tephra at the same elevation (5825 m.a.s.l.) on Volcán Socompa, but the structure of the 18S community (beta diversity) was significantly affected by the presence of penitentes on both Socompa and Llullaillaco. In addition, the 18S community was significantly different in tephra wetted by penitentes versus dry tephra sites across many elevations on Llullaillaco. Traditional phototrophs (algae and cyanobacteria) were abundant in wetter tephra associated with fumaroles, and algae (but not cyanobacteria) were common in tephra associated with penitentes. Dry tephra had neither algae nor cyanobacteria but did host potential phototrophs in the Rhodospirillales on Volcán Llullaillaco, but not on Socompa. These results provide new insights into the distribution of microbes across one of the most extreme terrestrial environments on Earth and provide the first ever glimpse of life associated with nieves penitentes, spire-shaped ice structures that are widespread across the mostly unexplored high-elevation Andean Central Volcanic Zone.

Freeze-thaw revival of rotifers and algae in a desiccated, high-elevation (5500 meters) microbial mat, high Andes, Perú.

This is the first study of the highest elevation cyanobacteria-dominated microbial mat yet described. The desiccated mat was sampled in 2010 from an ephemeral rock pool at 5500 m above sea level in the Cordillera Vilcanota of southern Perú. After being frozen for 6 years at -20 °C in the lab, pieces of the mat were sequenced to fully characterize both the 16 and 18S microbial communities and experiments were conducted to determine if organisms in the mat could revive and become active under the extreme freeze-thaw conditions that these mats experience in the field. Sequencing revealed an unexpectedly diverse, multi-trophic microbial community with 16S OTU richness comparable to similar, seasonally desiccated mats from the Dry Valleys of Antarctica and low elevation sites in the Atacama Desert region. The bacterial community of the mat was dominated by phototrophs in the Cyanobacteria (Nostoc) and the Rhodospirillales, whereas the eukaryotic community was dominated by predators such as bdelloid rotifers (Philodinidae). Microcosm experiments showed that bdelloid rotifers in the mat were able to come out of dormancy and actively forage even under realistic field conditions (diurnal temperature fluctuations of -12 °C at night to + 27 °C during the day), and after being frozen for 6 years. Our results broaden our understanding of the diversity of life in periodically desiccated, high-elevation habitats and demonstrate that extreme freeze-thaw cycles per se are not a major factor limiting the development of at least some members of these unique microbial mat systems.

Attentional performance may help to identify duloxetine responders in chronic pain fibromyalgia patients.

BACKGROUND: Long-term pain affects brain in response to attention tasks. This study aimed to verify the relationship between performance in a computerized visual attention test (CVAT) and response to duloxetine in fibromyalgia patients. Duloxetine is approved for the treatment but the response is not immediate. METHODS: Patients were drawn from a sample of 74 patients with chronic pain. These patients were selected because they kept their subjective perceptions of pain as severe after 1 week of duloxetine treatment. All patients were tested in the CVAT on two occasions: the first appointment and 7 days after starting duloxetine. RESULTS: After 6 weeks, the group was subdivided into responsive and non-responsive patients. Responsiveness was defined by a subjective improvement from severe to low-intensity or no-pain after the sixth week of duloxetine treatment. Responsive patients showed objective attentional improvements in the second test. Non-respondent patients did not exhibit changes in attentional performance in the second test as compared to the first one. CONCLUSIONS: The data were interpreted considering that persistent pain in fibromyalgia is maintained by central sensitization that may be associated with functional changes in the dorsolateral prefrontal cortex and the posterior parietal cortex. In responsive patients, duloxetine treatment may be responsible for a partial recovery of these regions. This may explain the early attentional improvement observed in the responsive patients after 1 week of treatment. Thus, attentional performance may help to predict which patients will respond to duloxetine treatment even before they can demonstrate subjective improvements in pain perception. SIGNIFICANCE: This study shows that an improvement in an attentional test is a reliable predictor of the treatment response even without any improvement in the perception of pain.

Modulation of the consolidation and reconsolidation of fear memory by three different serotonin receptors in hippocampus.

The process of memory formation is complex and highly dynamic. During learning, the newly acquired information is found in a fragile and labile state. Through a process known as consolidation, which requires specific mechanisms such as protein synthesis, the memory trace is stored and stabilized. It is known that when a consolidated memory is recalled, it again becomes labile and sensitive to disruption. To be maintained, this memory must undergo an additional process of restabilization called reconsolidation, which requires another phase of protein synthesis. Memory consolidation has been studied for more than a century, while the molecular mechanisms underlying the memory reconsolidation are starting to be elucidated. For this, is essential compare the participation of important neurotransmitters and its receptors in both processes in brain regions that play a central role in the fear response learning. With focus on serotonin (5-HT), a well characterized neurotransmitter that has been strongly implicated in learning and memory, we investigated, in the CA1 region of the dorsal hippocampus, whether the latest discovered serotonergic receptors, 5-HT5A, 5-HT6 and 5-HT7, are involved in the consolidation and reconsolidation of contextual fear conditioning (CFC) memory. For this, male rats with cannulae implanted in the CA1 region received immediately after the training or reactivation session, or 3h post-reactivation of the CFC, infusions of agonists or antagonists of the 5-HT5A, 5-HT6 and 5-HT7 receptors. After 24h, animals were subjected to a 3-min retention test. The results indicated that in the CA1 region of the hippocampus the 5-HT5A, 5-HT6 and 5-HT7 serotonin receptors participate in the reconsolidation of the CFC memory 3h post-reactivation. Additionally, the results suggest that the 5-HT6 and 5-HT7 receptors also participate in the consolidation of the CFC memory.

The application of non-Saccharomyces yeast in fermentations with limited aeration as a strategy for the production of wine with reduced alcohol content.

High alcohol concentrations reduce the complexity of wine sensory properties. In addition, health and economic drivers have the wine industry actively seeking technologies that facilitate the production of wines with lower alcohol content. One of the simplest approaches to achieve this aim would be the use of wine yeast strains which are less efficient at transforming grape sugars into ethanol, however commercially available wine yeasts produce very similar ethanol yields. Non-conventional yeast, in particular non-Saccharomyces species, have shown potential for producing wines with lower alcohol content. These yeasts are naturally present in the early stages of fermentation but in general are not capable of completing alcoholic fermentation. We have evaluated 48 non-Saccharomyces isolates to identify strains that, with limited aeration and in sequential inoculation regimes with S. cerevisiae, could be used for the production of wine with lower ethanol concentration. Two of these, Torulaspora delbrueckii AWRI1152 and Zygosaccharomyces bailii AWRI1578, enabled the production of wine with reduced ethanol concentration under limited aerobic conditions. Depending on the aeration regime T. delbrueckii AWRI1152 and Z. bailii AWRI1578 showed a reduction in ethanol concentration of 1.5% (v/v) and 2.0% (v/v) respectively, compared to the S. cerevisiae anaerobic control.

PACAP modulates the consolidation and extinction of the contextual fear conditioning through NMDA receptors.

Pituitary adenylate cyclase-activating polypeptide (PACAP) has a broad spectrum of biological functions including neurotransmitter, neurotrophic and neuroprotective. Moreover, it has been suggested that PACAP plays a role in the modulation of learning and memory as well as on the modulation of glutamate signaling. Thus, in the current study we investigated in the CA1 region of hippocampus and in the basolateral amygdala (BLA) the role of PACAP in the consolidation and extinction of contextual fear conditioning (CFC) and the interaction between PACAP and NMDA receptors. Male rats with cannulae implanted in the CA1 region of the hippocampus or in the BLA received immediately after the training or extinction training of the CFC infusions of the Vehicle, PACAP-38 (40 pg/side), PACAP 6-38 (40 pg/side) or PACAP 6-38 plus D-serine (50 µg/side). After 24h, the animals were subjected to a 3-min retention test. The results indicated that in the CA1 region of hippocampus, PACAP participates in the consolidation and extinction of the CFC, and in the BLA, PACAP participates only in the consolidation of the CFC. Additionally, the results suggest that the action of PACAP on the consolidation and extinction of the CFC is mediated by the glutamate NMDA receptors.

Bombas de infusión continua de jeringa en unidades neonatales / Continuous infusion pumps at neonatal intensive care units

Introduction: Continuous Infusion pumps (CIP) are frequently used at neonatal intensive care units (NICUs), to administer medications at flow rates lower than 1 ml/H. Various factors have been shown to alter their performance. No studies have been completed in Chile in this area. Objectives: To describe frequent clinical practices to administer medications through CIP at NICUs in Chile, and suggest recommendations about it. Methods: Four professionals at NICUs in 19 centers were surveyed regarding syringe size, flow rate and precautions. Results: When starting countinuous infusion, 81.9 percent of surveyed professionals use 50 cc syringes, and 66.7 percent of them use flow rates under 1 ml/h. Main precautions include elimination of bubbles in the circuit (51.4 percent), review of conections (38.9 percent) and precise fit between the syringe and the CIP (36.1 percent). Conclusions: In surveyed NICUs, low flow rates and 50cc syringes are frequently used to infuse medications. NICU staff must consider factors that affect the performance of CIP, prefer smaller syringes and flow rate over 1 ml/h for continuous infusion of drugs.

Introducción: En las unidades de cuidado intensivo neonatal (UCIN) se utilizan frecuentemente bombas de infusión continua (BIC) a flujos menores de 1 ml/h para administrar medicamentos. Está demostrado que distintos factores alteran el funcionamiento de las BIC a flujos bajos. En Chile, no existen estudios que describan prácticas relacionadas al uso de BIC. Objetivo: Describir prácticas clínicas frecuentes al administrar medicamentos en BIC en UCIN de Chile y proponer recomendaciones respecto a su uso. Método: Se encuestaron 4 profesionales de UCIN en 19 centros. Los principales aspectos evaluados fueron: tamaño de jeringa usado en las BIC, flujos de infusión continua utilizados y precauciones al instalar una BIC. Resultados: Al instalar una infusión continua, el 81,9 por ciento de los profesionales encuestados usa jeringas de 50 ml y el 66,7 por ciento utiliza flujos menores de 1 ml/h. Las principales precauciones fueron la eliminación de burbujas del circuito (51,4 por ciento), la revisión de las conexiones del sistema (38,9 por ciento) y el ajuste preciso entre jeringa y BIC (36,1 por ciento). Conclusiones: En las UCIN estudiadas se utilizan frecuentemente flujos bajos y jeringas de 50 ml para infundir medicamentos. Las UCIN deben considerar los factores que alteran el funcionamiento de las BIC y preferir el uso de jeringas de menor tamaño y flujos mayores de 1 ml/h para la infusión continua de medicamentos.

Microbial activity and diversity during extreme freeze-thaw cycles in periglacial soils, 5400 m elevation, Cordillera Vilcanota, Perú.

High-elevation periglacial soils are among the most extreme soil systems on Earth and may be good analogs for the polar regions of Mars where oligotrophic mineral soils abut with polar ice caps. Here we report on preliminary studies carried out during an expedition to an area where recent glacial retreat has exposed porous mineral soils to extreme, daily freeze-thaw cycles and high UV fluxes. We used in situ methods to show that inorganic nitrogen (NO(3) (-) and NH(4) (+)) was being actively cycled even during a period when diurnal soil temperatures (5 cm depth) ranged from -12 to 27 degrees C and when sub-zero, soil cooling rates reached 1.8 degrees C h(-1) (the most rapid soil cooling rates recorded to date). Furthermore, phylogenetic analyses of microbial phylotypes present at our highest sites (5410 m above sea level) showed the presence of nitrifying bacteria of the genus Nitrospira and newly discovered nitrite-oxidizing Betaproteobacteria. These soils were overwhelmingly dominated (>70% of phylotypes) by photosynthetic bacteria that were related to novel cyanobacteria previously found almost exclusively in other plant-free, high-elevation soils. We also demonstrated that soils from our highest sites had higher potential for mineralizing glutamate and higher microbial biomass than lower elevation soils that had been more recently covered by ice. Overall, our findings indicate that a diverse and robustly functioning microbial ecosystem is present in these previously unstudied high-elevation soils.

The earliest stages of ecosystem succession in high-elevation (5000 metres above sea level), recently deglaciated soils.

Global climate change has accelerated the pace of glacial retreat in high-latitude and high-elevation environments, exposing lands that remain devoid of vegetation for many years. The exposure of 'new' soil is particularly apparent at high elevations (5000 metres above sea level) in the Peruvian Andes, where extreme environmental conditions hinder plant colonization. Nonetheless, these seemingly barren soils contain a diverse microbial community; yet the biogeochemical role of micro-organisms at these extreme elevations remains unknown. Using biogeochemical and molecular techniques, we investigated the biological community structure and ecosystem functioning of the pre-plant stages of primary succession in soils along a high-Andean chronosequence. We found that recently glaciated soils were colonized by a diverse community of cyanobacteria during the first 4-5 years following glacial retreat. This significant increase in cyanobacterial diversity corresponded with equally dramatic increases in soil stability, heterotrophic microbial biomass, soil enzyme activity and the presence and abundance of photosynthetic and photoprotective pigments. Furthermore, we found that soil nitrogen-fixation rates increased almost two orders of magnitude during the first 4-5 years of succession, many years before the establishment of mosses, lichens or vascular plants. Carbon analyses (pyrolysis-gas chromatography/mass spectroscopy) of soil organic matter suggested that soil carbon along the chronosequence was of microbial origin. This indicates that inputs of nutrients and organic matter during early ecosystem development at these sites are dominated by microbial carbon and nitrogen fixation. Overall, our results indicate that photosynthetic and nitrogen-fixing bacteria play important roles in acquiring nutrients and facilitating ecological succession in soils near some of the highest elevation receding glaciers on the Earth.

Miastenia gravis en pediatría / Myastenia gravis in paediatrics

La miastenia gravis corresponde a una patología auto inmune que se presenta en todas las edades. Tiene una frecuencia general de 10 a 20 por 100 000 individuos y aproximadamente un 15 por ciento corresponde a niños. Se caracteriza por la presencia de debilidad muscular y fatiga fácil secundaria a una alteración de la transmisión sináptica neuromuscular. Su patogenia se basa en la presencia de anticuerpos antireceptor de acetilcolina que generan el bloqueo y destrucción de los receptores de acetilcolina de la unión neuromuscular. Estos anticuerpos al ser pesquisados en un paciente con clínica sugerente confirman el diagnóstico. A pesar del conocimiento actual de la enfermedad su tratamiento aún es controversial existiendo distintas alternativas. En la última década han existido avances en la descripción de mecanismos fisiopatológicos involucrados en la miastenia gravis y asimismo nuevas opciones terapéuticas. El objetivo de esta revisión fue actualizar el conocimiento de la miastenis gravis en pediatría principalmente en las áreas de diagnóstico y tratamiento. Se realizó una revisión en las bases de datos Cochrane, Medline y Doyma de los últimos 10 años. Los resultados muestran descripciones moleculares de la patología, experiencias de la timectomía como tratamiento en niños e investigaciones en el manejo inmunológico de la enfermedad.

Síndrome de activación macrofagico en pediatría: a propósito de cuatro casos / Activated macrophage syndrome in paediatrics: 4 clinical cases

Introducción: El Síndrome de Activación Macrofágico (SAM) es una entidad poco frecuente en la práctica pediátrica que se caracteriza por una excesiva activación del sistema macrofágico y por una liberación exagerada de citoquinas por parte de los linfocitos T, y que clínicamente se manifiesta como un síndrome semejante a una falla orgánica múltiple. Existe actualmente disparidad en la nomenclatura de este síndrome, y es así como a nivel de la reumatología pediátrica se mantiene el término de SAM, mientras que para los hemato-oncólogos esta enfermedad está incluida dentro de las diferentes variedades de histiocitosis. Objetivo: Actualizar el conocimiento respecto de la etiología, clínica y tratamiento del SAM, enfermedad de baja frecuencia y alta mortalidad, en relación al análisis de 4 casos clínicos. Casos clínicos: 2 pacientes eran portadores de una enfermedad reumatológica, Artritis Idiopática Juvenil, el tercer paciente presentaba elementos de Inmunodeficiencia, y el último niño de linfohistiocitosis familiar congénita. Los factores desencadenantes del SAM fueron fármacos en dos pacientes y una posible causa infecciosa en los dos restantes. Los cuatro pacientes sobrevivieron al proceso inicial después de recibir una terapia agresiva inmunosupresora con esteroides en altas dosis y ciclosporina intravenosa. Conclusión: La importancia de dar a conocer este síndrome, radica en que un diagnóstico precoz y una terapia agresiva, preferentemente con ciclosporina y pulsos de esteroides en altas dosis, puede mejorar significativamente el pronóstico de esta enfermedad.

The effect of corpus callosum agenesis on neocortical thickness and neuronal density of BALB/cCF mice.

We used acallosal and normal adult BALB/cCF mice to test the hypothesis that the development of the corpus callosum is relevant for the establishment of a normal structure of the neocortex. Neuronal density and thickness of individual layers were analyzed in neocortical regions with abundant callosal connections (area 6 and the 17/18a border) and in the relatively acallosal area 17. In area 6, acallosal mice exhibited a total neocortical thickness smaller than that of normal mice, as well as thinner layers II+III and IV. Similar data were obtained at the 17/18a border, where the total thickness of the cortex and of layers II+III was smaller in the acallosal mice than in normal ones. In contrast, no significant thickness differences were documented in area 17 of acallosal versus normal mice. The quantitative data obtained in the analyzed neocortical regions did not show differences in neuronal density between acallosal and normal mice. The reduced cortical thickness, associated with the comparatively normal neuronal density in neocortical regions which normally have abundant callosal connections, provides indirect indication of a reduction in the number of cortical neurons in acallosal mice. This assumption was also supported by the lack of evidence of neocortical alterations in the acallosal area 17. The present findings suggest that during development neocortical neurons destined to receive a massive callosal input may die as a result of lack of afferents. Altogether the present data indicate that the input provided by callosal axons is necessary for a normal development of the neocortex.

Time course of the effects of prenatal gamma irradiation on the dorsal lateral geniculate nucleus of Swiss mice.

A previous study reported that adult mice irradiated at the 16th embryonic day present a severe neuronal number reduction in the dorsal lateral geniculate thalamic nucleus. In the present study, we investigated the time course of the effects of prenatal irradiation on this thalamic nucleus. One day after irradiation, a great number of pyknotic figures were seen mainly in the cerebral proliferative zones. In the geniculate nucleus, only scattered pyknotic figures were identified. On the first week after birth, the geniculate nucleus presented frequent pyknotic figures. From five days after birth onwards, a severe shrinkage of the occipital cortex and a great reduction in the geniculate nucleus neuronal number were found. On the second week after birth this neuronal number reduction reached as high as 75%. At each postnatal analyzed age, severe volumetric geniculate nucleus shrinkage was combined to non-significant neuronal density variations. The presence of few pyknotic figures in the geniculate nucleus one day after irradiation and its delayed neuronal loss indicate an indirect effect of irradiation. We suggest that the effect upon the geniculate nucleus is secondary to the damage of the occipital cortex. A possible interpretation for thalamic neuronal loss is that geniculate neurons fail to establish cortical arbors after major target loss. In this case, the loss of trophic support should also be considered.

Effects of prenatal ionizing irradiation on the development of the ganglion cell layer of the mouse retina.

Prenatal exposure to ionizing irradiation has been shown to be an effective method to eliminate selectively certain neuronal population. This investigation studied the effects on the ganglion cell layer of the retinae of adult mice exposed to a gamma source (total dose=3 Gy) at 16 days gestation. There was a significant reduction in the total number of neurons (displaced amacrine+ganglion cells) in the ganglion cell layer (33%) that was mainly caused by a pronounced loss (59%) of displaced amacrine cells. The diameters of the surviving retinal ganglion cells were consistently larger than those of the controls. Prenatal irradiation is the first experimental approach that partially eliminates displaced amacrine cells. It is suggested that the morphogenesis of retinal ganglion cells may be affected by displaced amacrine cells.

Depletion of cortical target induced by prenatal ionizing irradiation: effects on the lateral geniculate nucleus and on the retinofugal pathways.

Studies using neonatal surgical lesions to reduce the target area of the retina have supported the idea that developing axons show only a limited specificity in their targeting. This investigation tested whether retinogeniculate axons adjust for partial target depletion by repositioning of axons. We used adult Swiss mice exposed to gamma rays at the time when layer IV cells are generated in the ventricular zone (16 days of gestation). Nissl-stained brain sections were used for histological analyses in thalamus and cortex. Retinal ganglion cells were backfilled from the optic tract with horseradish peroxidase. Intraocular injections of horseradish peroxidase were used to study the retinal projections. In the posterior cortex there was a nearly complete absence of layer IV. The irradiated animals showed a 75% reduction of the dorsal lateral geniculate nucleus. The ventral division, superior colliculus, and other visually related nuclei were not affected. The loss in the ganglion cells (15.7%) was significant but clearly smaller than that observed in the dorsal lateral geniculate nucleus (75%). Therefore, the shrinkage of the dorsal lateral geniculate nucleus led to a reduction in the area available for retinal projections. Despite partial target loss, pattern of retinal projections did not differ from that of the controls. The effect on the dorsal lateral geniculate nucleus is discussed in the light of differences between prenatal and neonatal damage of the presumptive visual cortex. The absence of aberrant retinal projections suggests that repositioning of axons is not the first mechanism employed by retinal axons to match connections in numerically disparate populations.

Sex differences in sensitivity to seizures elicited by pentylenetetrazol in mice.

Sex differences in sensitivity to seizures elicited by intraperitoneally injected pentylenetetrazol (PTZ) were studied in 240 (120 males and 120 females) adult Swiss mice. Animals were separated into four groups according to the dose that was injected: 40, 50, 60 and 70 mg/kg. Seizure severity was expressed by the following scoring scale: (0) no abnormal behavior; (1) myoclonus; (2) running bouncing (RB) clonus; (3) tonic hind limb extension (THE). The analyses of the dose-response curves indicated that females were more susceptible than males when the 50- and 60-mg/kg doses were used. Specifically, females often displayed RB clonus, while males frequently displayed only myoclonus or no abnormal behavior. No significant sex differences were demonstrated when either the 40- or the 70-mg/kg doses were used. These data indicate that, for a specific range of doses, sex differences in seizure susceptibility can be clearly demonstrated with the use of intraperitoneally injected PTZ. In this sense, this method could be used as a tool to investigate the role played by sexual hormones in regulating the sensitivity of the gamma-aminobutiric acid (GABA(A)) receptor complex (GRC).

Influences of handedness and gender on the grooved pegboard test.

We studied performance on the Grooved Pegboard Test upon repeated trials and transfer of training between the hands in the first trial. The classification of handedness was based on the writing hand. We employed three trials for each hand and two different protocols for the order in which the hands started the test. For the three trials combined, women were faster than men. From the first to the second trial, there was an improvement in performance for both sexes. Within the first trial, sex differences reached significance and the protocol interacted with handedness. In this trial, only left-handed men were found to benefit from previous opposite-hand performance. It is speculated that a larger corpus callosum in left-handed men allows for the greater transfer of training between the hands.

Empirical analysis of the selective attention and associated behavior checklists of the Aggregate neurobehavioral student health and educational review.

For 111 referred children, the Behavior Observation (BO) and the Selective Attention (SA) components of the Aggregate Neurobehavioral Student Health and Educational Review (ANSER) were completed by mothers and teachers and the Pediatric Examination of Educational Readiness at Middle Childhood was completed by the pediatrician. Smaller samples were used to study concurrent validity. The questionnaires presented high internal reliability. Factor analyses of the BO questionnaires resulted in a common primary factor of "Aggressiveness" for ratings by mothers and teachers. For the SA, "Hyperactivity" (mothers) and "Inattention" (teachers) accounted for the majority of variance. There were modest correlations between teachers and mothers. The correlation between the pediatrician and teachers reached the highest value. The BO-Teachers form was significantly related to the Teacher Report Form and the Conners Teacher Rating Scale. The authors concluded that the ANSER presents concurrent validity for teacher ratings, items predictive of atypical behavior, and a unique pool for defining a subgroup of children with attentional disorders. The limited relationship between mothers and teachers may be ascribed to different interpretations of the same items.