Tomasz Cecot

Lesion of the ventral tegmental area amplifies stimulation-induced Fos expression in the rat brain

Unilateral lesions of the ventral tegmental area (VTA), the key structure of the mesolimbic system, facilitate behavioral responses induced by electrical stimulation of the VTA in the contralateral hemisphere. In search of the neuronal mechanism behind this phenomenon, Fos expression was used to measure neuronal activation of the target mesolimbic structures in rats subjected to unilateral electrocoagulation and simultaneously to contralateral electrical stimulation of the VTA (L/S group). These were compared to the level of mesolimbic activation after unilateral electrocoagulation of the VTA (L group), unilateral electrical stimulation of the VTA (S group) and bilateral electrode implantation into the VTA in the sham (Sh) group. We found that unilateral stimulation of the VTA alone increased the density of Fos containing neurons in the ipsilateral mesolimbic target structures: nucleus accumbens, lateral septum and amygdala in comparison with the sham group. However, unilateral lesion of the VTA was devoid of effect in non-stimulated (L) rats and it significantly amplified the stimulation-induced Fos-immunoreactivity (L/S vs S group). Stimulation of the VTA performed after contralateral lesion (L/S) evoked strong bilateral induction of Fos expression in the mesolimbic structures involved in motivation and reward (nucleus accumbens and lateral septum) and the processing of the reinforcing properties of olfactory stimuli (anterior cortical amygdaloid nucleus) in parallel with facilitation of behavioral function measured as shortened latency of eating or exploration. Our data suggest that VTA lesion sensitizes mesolimbic system to stimuli by suppressing an inhibitory influence of brain areas afferenting the VTA.

Accessory (multiple) renal arteries – Differences in frequency according to population, visualizing techniques and stage of morphological development

The aim of this paper is to comprehensively analyze the literature focused on frequency of the presence of the accessory renal arteries in the human body. A systematic analysis of papers has been made. With regard to ethnicity, the incidence of accessory renal arteries fluctuates from 4% in a Malaysian population to 61.5% in a Brazilian population. The frequency is lowest in eastern and southern Asia (from 4% to 18.4%). In some, not ethnically homogenous populations, wide span of occurrence of accessory renal arteries is described (e.g. American – averaging from 18% to 28.8%). A higher frequency of accessory renal arteries was observed in fetuses compared to adults. Moreover, differences in the presence and number of accessory renal arteries reported in different papers are a consequence of type of visualizing technique used in research – especially when computed tomography and anatomical dissection were compared. The increasing number of surgical interventions, especially where laparoscopic methods are concerned, underlines the importance of such knowledge especially to surgeons, interventional radiologists, nephrologists, and vascular surgeons.

The Epidemiological, Morphological, and Clinical Aspects of the Cervical Ribs in Humans.

A familiarity with the anatomy of some types of bone anomalies is necessary for clinicians involved in many medical areas. The aim of this paper is to review the newest literature concerning the morphology, embryology, clinical image, and therapeutic methods of the cervical ribs in the humans. The incidence of cervical ribs has been found to vary from 0.58% in Malaysian population to 6.2% in Turkish population. Cervical ribs have clinical implications that are generally divided into neurological or vascular. This study is of particular importance for clinicians, as early identification of cervical ribs may prevent life-threatening complications.