No We Kan’t. Percezione, linguaggio e realtà in prospettiva semiotica

Articolo che riprende alcuni temi di "Kant e l'ornitorinco" di Umberto Eco per discuterne l'attualità, in particolare il tema della percezione anche in relazione alle più moderne teorie cognitiviste

Repeated administration of the spasmolytic otilonium bromide counteracts functional and neurotransmitters’ changes in the colon of rats underwent to wrap restraint stress

Otilonium bromide (OB) is a quaternary ammonium derivative successfully used for the treatment of irritable bowel syndrome (IBS). Several in vitro experiments in human and rat colon demonstrated its spasmolytic capability due to the block of muscarinic and tachykinin receptors and L-type Ca2+ channels. Moreover, in vivo OB administrations showed interesting interaction with the enteric nervous system in healthy rats (1). The wrap restrain stress (WRS) is considered an adequate model of psychosocial stressor, able to induce most of the IBS signs and symptoms. WRS leads to important changes in the enteric neurotransmitters of rat colon, as recently demonstrated (2). Consequently, we chose this animal model to investigate whether a repeated, oral treatment with OB prevented the functional and neurotransmitters’ changes reported in rats underwent to WRS. The results obtained by using multiple experimental approaches (in vivo colonic functional evaluations, routine histology, immunohistochemistry and western blot) showed that OB is able to counteract most of the morphological changes caused by WRS in the colonic wall. In particular, the drug prevents the decrease in SP-, NK1r-, nNOS-, VIP- and S100β-immunoreactivity (IR) and the increase in CGRP- and CRF1r-IR detected in WRS rats. On the contrary, OB does not interfere with the mild mucosal inflammation and does not affect the increase in CRF2r-immunoreactive neurons observed in WRS rats. Moreover, OB per se increases the muscarinic receptor 2 expression in the muscle wall and decreases the number of the myenteric ChAT-immunoreactive neurons. Functional findings show a significantly reduction in the number of spontaneous abdominal contraction in OB treated rats. The ability of OB to block L-type Ca2+ channels, also expressed by enteric neurons, might explain the drug efficacy in preventing excessive neuronal response to stress. This work was supported by grants from Menarini I.F.R

The wrap partial restrain stress, an animal model of the irritable bowel syndrome: immunohistochemical and functional characterization

Several animal models have been proposed to mimic the human irritable bowel syndrome (IBS) all based on two etio-pathogenic hypotheses: infection and stress, both responsible for the development of a local inflammation. We investigated the wrap partial restrain stress (WRS) animal model with the aim to evaluate its validity in understanding the human IBS. Male Wistar rats were used and WRS was maintained for 2h. Abdominal contractions (AC) were recorded by a distension balloon in the colon-rectum. The number of faecal pellets and their total weight were determined. Colonic specimens from both groups were examined by routine histology, immunohistochemistry and western blot (WB). WRS animals were characterized by: 1) a statistically significant increase in the number of AC and in the mean number and mean weight of faecal pellets; 2) the presence of large clusters of mononucleated cells and a significant increase in eosinophilic granulocytes and mast cells in the mucosa; 3) reduction of GLP1r-immunoreactivity (IR) located at the basolat- eral periphery and the Golgi level of the cells of the glandular funds; 4) an increase in CGRP-IR in the lamina propria; 5) no significant difference in the muscle wall for Cav1, L- type Ca+2-channels, Mr2, NK1r and NK2r; 6) a significant decrease in the myenteric and a significant increase in the submucous NK1-IR neuron number; 7) a significant decrease in Substance P-IR in the myenteric plexus and muscle coat; 8) a significant decrease in myenteric and submucous nNOS-IR neuron number; 9) no difference in ChAT-IR neurons of both enteric plexuses; 10) a reduction in S-100-IR in the entire colonic wall; 11) no difference in the total number of neurons evaluated by the pan-neuronal marker PGP 9.5; 12) no change of all the ICC populations. The functional data are in favor of a lowering in the colonic wall distention threshold; the morphological results obtained in the lamina propria demonstrate the presence of a local inflammation, particularly intense at the level of the mucosa. Both of these findings agree with the hypothesis that inflammation might have a main role in the insurgence and maintenance of the typical IBS symptoms and support the validity of our WRS model. Moreover, while the smooth muscle cells do not show any significant variation, numerous and consistent changes in the excitatory, inhibitory and NK1r-IR neurons are detected

Changes in matrix extracellular phosphoglycoprotein expression before and during in vitro osteogenic differentiation of human dental papilla mesenchymal cells.

The purpose of this study is to characterise the expression of matrix extracellular phosphoglycoprotein (MEPE) in cultured mesenchymal cells isolated from human dental papilla (PaMCs) of impacted third molars either before or during differentiation of these cells into osteo/odontoblasts. PaMCs, like mesenchymal cells deriving from human dental pulp (DPMCs), resulted positive for a number of mesenchymal markers including CD146 and STRO-1. During the first week in culture they showed a faster proliferation rate than DPMCs, coupled to an earlier down-regulation of MEPE. Also when the cells were further cultured in osteogenic medium (containing β-glycerophosphate, ascorbic acid and dexamethasone) for 40 days, MEPE down-regulation coupled to an increased expression of osteogenic markers, such as osteocalcin and alkaline phosphatase, occurred earlier in PaMCs than in DPMCs. Thus, our data, indicating that also in PaMCs MEPE expression is higher when cells proliferate, whereas it is downregulated as cells differentiated, are in favour of a role of MEPE as an early regulator of odontogenic differentiation. We also confirm the superior proliferative potential of PaMCs in comparison with DPMCs, coupled to a more rapid induction of osteogenic differentiation. Therefore, these cells represent an optimal source to be conveniently used for dental tissue engineering and tooth regeneration