The predictive value of cranial ultrasound and of somatosensory evoked potentials after nerve stimulation for adverse neurological outcome in preterm infants

Thirty-nine preterm infants were studied to compare the predictive value of somatosensory evoked responses (SEPs) following median-nerve and posterior tibial-nerve stimulation with the predictive value of cranial ultrasound. With regard to the SEP, a normal median-nerve response was by no means a guarantee of a normal outcome. A normal posterior tibial-nerve response, however, almost guaranteed a normal outcome, but the test was very time consuming and the number of false positive responses was high (sensitivity. 95.6%, specificity 50%). The presence of parenchymal involvement, either due to a haemorrhage or cystic leukomalacia predicted cerebral palsy with a sensitivity of 95.6% and a specificity of 68.5%. The combination of an abnormal posterior tibial response and the presence of parenchymal brain lesions had the best predictive value with a sensitivity of 91.3% and a specificity of 81.2%. These results show that, although posterior tibial-rferve responses have a better predictive value than median-nerve responses, these values were lower than that of cranial ultrasound. The best prediction was obtained when a combination of posterior-tibial responses and cranial ultrasound was used.     

The structure of the inferior lobe of the teleost hypothalamus.

Electron microscopic and Golgi studies on the inferior lobes of sunfish and goldfish are described. The inferior lobe consists primarily of a nucleus ventricularis of densely packed cells surrounding the lateral recess of the third ventricle, and a peripherally situated nucleus diffusus consisting mostly of scattered neurons. A cell-sparse zone of dense neuropil is located between the two cellular areas. Neurons of both nuclei have spiny dendrites and axons which originate from basal dendrites. In some cases axons are found to send a collateral into the cell-sparse zone. Neurons of the nucleus diffusus possess collaterals that extend a considerable distance within the nucleus itself. The ultrastructure of cells of both nuclei reveals cytoplasmic organelles typical of most neurons. Synapses containing dense-cored and clear vesicles are present on the spines and shafts of the dendrites of both neuronal types. In only rare cases synapses were observed on the soma of neurons of the nucleus ventricularis. Possible anatomical substrates involved in the control of feeding and aggression in teleosts are considered in light of the present findings. Morphological similarities of the inferior lobes and related areas in various fishes and amphibians are discussed and their possible significance for the understanding of the evolution of hypothalamic mechanisms is considered.     

Chromatophore systems in teleosts and cephalopods: a levels oriented analysis of convergent systems.

The neural control of chromatophore display in cephalopod mollusks and teleost fishes is reviewed in the context of convergence of functional-anatomical pathways and mechanisms at several levels of organization. The effector elements or chromatophores are different in origin and design in the two groups of animals. Major functional differences appear to be in the speed of response (greatest in cephalopods) and the magnitude of non-neural control mechanisms (greatest in teleosts). Despite the differences, the elements demonstrate striking overall functional similarity. Elements of different types form highly organized array patterns of similar general complexity. Innervation patterns in cephalopods and teleosts seem comparable, with control being unidirectional (albeit in opposite directions); some elements demonstrate polyaxonal innervation. Motor units in both groups are generally composed of many chromatophores. Packard's concept of 'cronological units' of similar age-classes of chromatophores being innervated by similar age-classes of motor neurons greatly simplifies the understanding of relationships between the static arrays and the physiological units that utilize them to produce chromatic displays. The lower motor control areas for both groups have been grossly identified. Chromatomotor neurons in cephalopods are mostly located in the chromatophore lobes of the subesophageal brain while comparable systems in teleosts are situated in sympathetic chain ganglia (preganglionics) and the rostral spinal cord (postganglionics). Chromatic components are the simplest visually detectable units of color display, e.g. vertical bands and fin spots. They combine to form more complex chromatic patterns, which, in turn, are integrated with components of skin texture, posture and movement to produce display behaviors. Complexity of such systems seems to be of the same order of magnitude in both cephalopods and teleosts. Areas of the CNS related to each of the categorical levels have not been clearly defined. Crude patterning may take place in the basal and, perhaps, peduncle lobes in cephalopods and in the lower and intermediate medulla in teleosts. In both groups, higher level control relates to areas involved in sensorimotor integration and mediation of agonistic, sexual, and, perhaps, other types of behavior: the peduncle and optic lobes in cephalopods and the hypothalamus, tegmentum, otic tectum, torus semicircularis, thalamus and telencephalon in fishes. The systems appear to parallel each other in being organized hierarchically, with similar levels of complexity. Some of the regions may be especially important for regulating color patterns in response to visual input. Overall, chromatomotor control systems in cephalopods and teleosts demonstrate many apparent convergent features. Possible factors responsible for the similarities are discussed.(ABSTRACT TRUNCATED AT 400 WORDS)     

Nucleotide oligomerization domain 1 is a dominant pathway for NOS2 induction in vascular smooth muscle cells: comparison with Toll-like receptor 4 responses in macrophages

Background and purpose:

Gram-negative bacteria contain ligands for Toll-like receptor (TLR) 4 and nucleotide oligomerization domain (NOD) 1 receptors. Lipopolysaccharide (LPS) activates TLR4, while peptidoglycan products activate NOD1. Activation of NOD1 by the specific agonist FK565 results in a profound vascular dysfunction and experimental shock in vivo.

Experimental approach:

Here, we have analysed a number of pharmacological inhibitors to characterize the role of key signalling pathways in the induction of NOS2 following TLR4 or NOD1 activation.

Key results:

Vascular smooth muscle (VSM) cells expressed NOD1 mRNA and protein, and, after challenge with Escherichia coli or FK565, NOS2 protein and activity were induced. Macrophages had negligible levels of NOD1 and were unaffected by FK565, but responded to E. coli and LPS by releasing increased NO and expression of NOS2 protein. Classic pharmacological inhibitors for NF-κB (SC-514) and mitogen-activated protein kinase (SB203580, PD98059) signalling pathways inhibited responses in both cell types regardless of agonist. While TLR4-mediated responses in macrophages were specifically inhibited by the pan-caspase inhibitor z-VAD-fmk and the PKC inhibitor Gö6976, NOD1-mediated responses in VSM cells were inhibited by the Rip2 inhibitor PP2.

Conclusions and implications:

Our findings suggest a selective role for NOD1 in VSM cells, and highlight NOD1 as a potential novel therapeutic target for the treatment of vascular inflammation.