Abdominal aortic aneurysm associated with abdominal visceral diseases.

Abdominal aortic aneurysm (AAA) occurs in advanced age. As such, its frequency has increased with the general ageing of the population as has the possibility of finding AAA associated with abdominal visceral disease, especially neoplasms. A malignant mass is present in 4% of patients who undergo aortic reconstruction for AAA. Since surgical treatment for both is often potentially life-threatening, the surgeon is faced with a series of treatment decisions concerning foremost timing of the operation. The main worry is that simultaneous treatment carries a potential risk of infection of the vascular graft. On the other hand, a 2-phase procedure is also burdened by risks linked to a second anaesthesia and a second surgical operation carried out on scar or contaminated tissue and the worsening of one of the 2 potentially life-threatening illnesses. In this situation endovascular treatment of an AAA may represent an advantageous alternative therapeutic strategy.

Occurrence of D-aspartate in the harderian gland of Podarcis s. sicula and its effect on gland secretion.

High concentrations of free D-aspartate (D-Asp), an amino acid well known for its neuroexcitatory activity, are endogeneously present in the Harderian gland (HG) of the lizard Podarcis s. sicula. This orbital gland consists of two different parts: the medial part, which is prevalently a mucous acinar gland, and the lateral part, which is a serous tubulo-acinar gland. To determine the physiological effect of D-Asp on exocrine secretion in HG, D-Asp (2.0 micromol/g b.w.) was injected intraperitoneally into lizards. We found that highest accumulations of exogenous D-Asp in HGs occurred 15 hr after the injection. Specifically, exogenous D-Asp prevalently stimulated serous secretion from the lateral portion of the gland, where immunohistochemical analysis revealed a major accumulation. Similarly, in the medial part of the gland, highly sulfated mucosubstances were observed after D-Asp injection. Further, in both parts of the HG, the electron microscope revealed euchromatic nuclei, a prominent rough endoplasmic reticulum, as well as numerous secretory granules within the acinar cells. Thus, following D-Asp injection, a 60% increase in HG total protein was detected. In addition, exogenous D-Asp induced changes in the electrophoretic pattern of HG. In conclusion, although further investigations are still needed to clarify the molecular pathway induced by D-Asp in exocrine secretion, this study does indicate that free D-Asp plays a significant role in the secretory activity of this gland.

Morphological changes in frog mast cells induced by nerve stimulation in vivo.

We investigated at both histochemical and ultrastructural levels the effects of unilateral electrical stimulation in vivo of the frog hypoglossal nerve on the mast cells (MCs) within the nerve fascicles and among the axon terminals. The right ventral root of the hypoglossal nerve in different experiments was stimulated respectively for 1, 3, 5, 10 min with over-threshold stimuli (10 Hz; 2 ms duration). The stimulations at 3, 5 and 10 min caused a progressive degranulation and histochemical and ultrastructural changes of the MCs at the stimulated side. The morphological changes consisted of the loss of Alcian Blue secretory content and of a progressive release of safranin+ secretory granules, depending upon duration of stimulation. The ultrastructural study showed that granules are discharged whole into the microenvironment or may release their content through exocytosis. A functional relationship between nerve and MCs is also suggested by the close anatomical association between MCs and pre-terminal axons observed following 10 min of hypoglossal stimulation. No changes in MC morphology occurred after 1 min of electrical stimulation. The results suggest that active cholinergic fibres can modulate MC secretion.