Morphological and functional characteristics of satellite glial cells in the peripheral nervous system.

Satellite glial cells are specialised cells that form a functional perineuronal sheath around sensory ganglion neurons. There are a large number of studies that reveal the morphological and functional characteristics of these cells. Satellite glial cells have been studied both in intact ganglions and in tissue cultures, using light and transmission electron microscopy, immunohistochemical and other methods. Satellite glial cells have polygonal form; they are mononuclear and have developed synthetic organelles, numerous receptors, adhesion molecules and ion channels, which enable them to interact with adjacent neurons, as well as transmit signals in the ganglions of the peripheral nervous system. Based on the literature data, satellite glial cells thanks to their characteristics can receive signals from other cells and react to changes in their surroundings. Previous studies have investigated the potential role of satellite glial cells in the formation of the blood-nervous tissue barrier of the peripheral nervous system, as well as in the neuropathic pain genesis. Some recent discoveries support the fact that satellite glial cells can participate in controlling of local viral infections and protecting pseudounipolar neurons from mentioned infections.

The superficial palmar branch of the radial artery: a corrosion cast study.

BACKGROUND: Surgical procedures such as thenar flaps and radial artery (RA) harvesting call for an elaborate anatomical study of the RA's superficial palmar branch (SPB). The aim of this study was to describe the branching pattern of this vessel related to the morphometric characteristics and variations of this artery. MATERIALS AND METHODS: Twenty 4% formalin solution-injected hands were dissected. For the morphometric study we used another group of 35 human hands of adult persons, injected with methyl methacrylate fluid into the ulnar and radial arteries. As soon as polymerisation was completed, a 40% solution of potassium hydroxide was applied for corrosion. The vascular arterial casts were examined under the stereoscopic microscope and precise drawings of each specimen were made. RESULTS: In the majority of cases (75%) SPB passed superficially, over the abductor pollicis brevis muscle. The mean diameter of the SPB, very variable depending on its length and field of supply, was 1.52 ± 0.49 mm, ranging from 0.8 to 2.7 mm. Developed SPB type, was present in 31.4% of hands, with the diameter of 1.7 mm and larger (mean 1.95 mm), continuing distally to become the radialis indicis artery, with an average calibre of 1.2 mm, and with important branches to the thumb. In most hands (68.6%), the hypoplastic SPB, was present, with a mean diameter of 1.17 mm, and the field of supply within the thenar area. CONCLUSIONS: Knowledge of the SPB dominance and existence of anastomotic vessels in its field of supply are of importance to avoid the risk of possible ischaemic sequelae in the hand associated with harvesting the RA.

Morphometric multislice computed tomography examination of the craniovertebral junction in neck flexion and extension.

BACKGROUND: Detailed study of the craniovertebral junction (CVJ) is necessary to completely understand the mechanism of its flexion and extension. MATERIALS AND METHODS: One cadaver head was sectioned in the sagittal plane. Also, in 22 volunteers, examined using the multislice computed tomography (MSCT), 14 parameters and 2 angles were measured in the neutral position, flexion and extension. RESULTS: The obtained measurements showed the anterior part of the occiput to move inferiorly in flexion, and the anterior atlas arch and the tip of the dens to get closer to the basion. At the same time, the opisthion moves superiorly, but the cervical spine bends anteriorly. Consequently, the dens-opisthion diameter and the opisthion-posterior atlas arch distance slightly decrease in length, whilst the arches of the atlas (C1), axis (C2) and C3 vertebra become more distant. Following extension, the posterior part of the occiput moves inferiorly, so that the basion-dens tip, the basion-axis arch, and the basion-posterior atlas arch distances increase in length. In contrast, the distances of the C1-C3 arches decrease in length. The angle between the foramen magnum and the dens tip decreases 1.620 on average in flexion, but increases 3.230 on average in extension. The angle between the axis body and the opisthion also decreases in flexion (mean, 3.360) and increases in extension (mean, 6.570). Among the congenital anomalies, a partial agenesis of the posterior atlas arch was revealed (4.5%), as well as an anterior dehiscence of the C1 foramen transversarium (13.6%). CONCLUSIONS: The mentioned measurements improved our understanding of the CVJ biomechanics. The obtained data can be useful in the evaluation of the CVJ instability caused by trauma, congenital anomalies and certain spine diseases.