Substantial variability in morphological scaling among bumblebee colonies.

Differences in organ scaling among individuals may play an important role in determining behavioural variation. In social insects, there are well-documented intraspecific differences in colony behaviour, but the extent that organ scaling differs within and between colonies remains unclear. Using 12 different colonies of the bumblebee Bombus terrestris, we aim to address this knowledge gap by measuring the scaling relationships between three different organs (compound eyes, wings and antennae) and body size in workers. Though colonies were exposed to different rearing temperatures, this environmental variability did not explain the differences of the scaling relationships. Two colonies had differences in wing versus antenna slopes, three colonies showed differences in wing versus eye slopes and a single colony has differences between eye versus antenna slopes. There are also differences in antennae scaling slopes between three different colonies, and we present evidence for putative trade-offs in morphological investment. We discuss the utility of having variable scaling among colonies and the implication for understanding variability in colony fitness and behaviour.

Transmitter phenotypes of commissural interneurons in the lamprey spinal cord.

The fundamental network for locomotion in all vertebrates contains a central pattern generator or CPG that produces the required motor output in the spinal cord. In the lamprey spinal cord different classes of interneuron's forming the core CPG circuitry have been characterized based on their morphological and electrophysiological features. The commissural interneuron's (C-INs) represent one essential component of CPG that have been implicated in controlling left-right alternation of the motor activity during swimming. However, it is still unclear if the C-INs displays a homogenous neurotransmitter phenotype and how they are distributed. In this paper we investigated the segmental distribution of glycine, glutamate and GABA-immunoreactive (ir) C-INs by combining retrograde Neurobiotin tracing with specific antibodies for these transmitters. The C-INs were more abundant in caudal and rostral segments adjacent to the injection site and their number gradually decreased in more distal segments, suggesting that these interneurons project over a short distance. The glycine-ir neurons represented around 50% of the total C-INs, while glutamate-ir neurons represented only 29%. Both types of C-INs were homogenously distributed over different segments along the spinal cord. Finally, no Neurobiotin labeled C-INs displayed GABA-ir, although many interneurons were ir to GABA, suggesting that GABAergic interneurons are not directly responsible for controlling left-right alternation of activity during locomotion in lamprey. Overall, these results show that the C-INs display a gradual rostrocaudal distribution and consist of both glycine- and glutamate-ir neurons. The difference in the proportion of inhibitory and excitatory C-INs represents an anatomical substrate that can ensure the predominance of alternating activity during locomotion.

Anestesia conductiva para operación cesárea en paciente con estenosis de prótesis aórtica mecánica / Conductive anesthesia for cesarean section in patient with aortic stenosis

Reportamos el caso de una paciente de 34 años, primigestante, con reemplazo valvular mecánico aórtico y mitral, pero con disfunción de la prótesis aórtica con evidencia ecocardiográfica de estenosis con un área valvular menor de 0.6 cm2 . Aunque existen controversias acerca del uso de anestesia regional en estas pacientes, fue utilizada una técnica epidural con monitoreo invasivo. Discutimos los objetivos hemodinámicos de cualquier técnica anestésica en pacientes con este tipo de patología y concluimos que una anestesia epidural puede ser utilizada manteniendo la paciente con presión de llenado ventricular izquierdo adecuada y evitando disminuciones súbitas en la resistencia vascular sistémica. La paciente fue sometida a cesárea obteniéndose un bebé en buenas condiciones y no se presentó ninguna complicación