ANP (Atrial Natriuretic Peptide) presence in the heart of a tunicate, Ciona intestinalis.

Atrial natriuretic peptide was found in the heart of vertebrates, we studied the ANP presence in the heart of Ciona intestinalis. This is animal is very important because of the its evolutionary position between invertebrates and vertebrates. ANP presence was only revealed in myoepithelial cells of the myocardium. Results suggest the hypothesis that ANP is present not only in the vertebrates but also in the invertebrates and in Ciona heart ANP might play a similar role like in the heart of vertebrates.

Modifications of atrial natriuretic peptide and vasopressin peptides in the rat hypothalamic supraoptic nucleus during resistance training.

Many studies have demonstrated the involvement of atrial natriuretic peptide (ANP) and vasopressin (VP) in the homeostasis of body fluids, but few studies have regarded the hypothalamic magnocellular neurosecretory system during physical exercises. The aim of the present immunohistochemical work is to study the activity of ANP and VP secreting neurons of the hypothalamic supraoptic nucleus during and after resistance training. The study was carried out in Wistar rats trained by a physical resistance-type exercise, using a rung ladder and a varying load fastened to the tail of each rat; the exercise lasted 20 min everyday for periods of 15, 30 and 45 days. Animal groups were sacrificed at the end of each training period and one group was sacrificed after 60 days from the beginning of training, i.e.15 days after completing a 45 day training. The results show that ANP and VP-immunopositivity is at first lesser in the trained rats than in the corresponding controls and then increases from the 15th to the 45th day of training; the increase of the immunopositivity in the trained rats indicates a decreased degranulation of the neurons. The comparison between VP and ANP-immunopositivity suggests that in the early phase of training VP-release in the bloodstream is higher than ANP-release, therefore the antidiuretic action of VP is expected to prevail on ANP action and an electrolyte unbalance may occur.

ANP and insulin presence in human foetal pancreas.

Aim of this work is to investigate the presence of Atrial natriuretic peptide (ANP) and insulin in human foetal pancreas from not diabetic and diabetic mothers. The data literature evidenced relationship between serum ANP and insulin. The our work carried out on sections immunostained for ANP and insulin showed positivity for ANP and insulin in beta-cells of pancreas from diabetic mothers, while positivity for insulin in beta-cells of foetuses from not diabetic mothers. Results indicate that the insulin presence stimulates the ANP synthesis in pancreas of human foetuses from diabetic mothers.

Atrial natriuretic factor, but not oxytocin, is present in atherosclerotic plaques of human common carotid arteries.

We performed a study on 25 common carotid arteries (CCA) affected by atherosclerotic plaques, comparing them to 25 normal CCA. We researched the presence and localisation of atrial natriuretic factor (ANF) and oxytocin (OX) by immunohistochemistry. We found ANF abundantly expressed in plaques, mainly localising in intima and subintima layers; by contrast normal vessels were scarcely positive or negative; finally, OX resulted negative or weakly positive in both atherosclerotic and normal vessels. Our results show for the first time ANF presence in atherosclerotic plaques of CCA and are in agreement with other studies, mainly performed in vitro, that hypothesise the involvement of this molecule in the modulation of atherosclerotic inflammatory lesions and its use as anti-inflammatory agent.

Anatomical and clinical study on effects of sonography with pulse inversion and microbubble contrast in rabbit kidney.

Aim of the present study was to evaluate by transmission electron microscope (TEM) modifications in rabbit kidney-parenchyma after submission to ultrasound contrast agent (UCA) with Pulse Inversion Harmonic Imaging (PIHI). Seven inbred male albino rabbits were divided into three groups: 1) control group (n = 1 animal); 2) sonicated group (n = 3 animals); 3) sonicated group with UCA injection (CEUS) (n = 3 animals). The first group was not exposed to ultrasonography (US) and/or UCA. The second and third groups underwent baseline US and later to US with PIHI with a high mechanical index; in the third group UCA was simultaneously administered. Ultrastructural studies and image analysis were blindly performed on 50 samples (2mm3), including cortex and medulla, by two experienced pathologists with TEM. By TEM observations of the first and second groups showed no structural modifications of renal cortex and medulla. TEM observations of the third group showed ultrastructural changes of renal corpuscle, proximal and distal convoluted tubules and collecting tubules; further in the most of observed sections the filtration membrane had an alteration of typical trilaminar pattern and vacuolisation of glomerular endothelial cells with irregular edges. Therefore in rabbit kidney submitted to CEUS some ultrastructural modifications were observed.

Ultrastructural biologic effects of sonography with pulse inversion and microbubble contrast in rabbit liver.

PURPOSE: This prospective study was conducted to evaluate the biologic effects of microbubble destruction with pulse-inversion harmonic imaging on rabbit liver parenchyma. METHODS: The livers of 6 albino rabbits were examined sonographically by a single investigator. Three rabbits underwent contrast-enhanced sonography, with scanning starting 5 seconds after injection by using pulse-inversion harmonic imaging with a mechanical index of 1.2. Four time-triggered images were recorded at a rate of 1 frame every 2 seconds. For comparison, 3 control rabbits had pulse-inversion harmonic imaging with a mechanical index of 1.2 only, without contrast medium. Immediately after sonography, the animals were killed and uninterrupted, thin serial sections of the liver from both groups were analyzed by energy-filtered transmission electron microscopy. RESULTS: The hepatic parenchyma of rabbits exposed to contrast agents had ultrastructural damage: mitochondria with fragmented crests; interrupted rough endoplasmic reticulum; enlarged intercellular spaces; highly vacuolized cytoplasmic areas; dilated sinusoids, sometimes with an irregular and interrupted endothelial wall; fragmented hepatocyte microvilli in dilated spaces of Disse; fragmented or missing microvilli in bile canaliculi; vacuolated and lysosome-deprived hepatic cytoplasm around the bile canaliculi; markedly injured or fragmented endothelium in larger vessels; and damaged basal membrane. Control-group results indicated that exposure to ultrasound alone did not cause ultrastructural damage to hepatic cells. CONCLUSIONS: Simultaneous exposure to contrast administration and pulse-inversion harmonic imaging with a high mechanical index causes ultrastructural damage in the rabbit liver.