Relationships between summer Thermal variations and cell proliferation in heterothermic vertebrates, as revealed by PCNA expression in the brain of adult Rana bergeri (Günther, 1986)

About the issue if the natural encephalic proliferative activities can be infl uenced by the seasonal (thermal and photoperiodic) cyclic fl uctuations in adult earth-dwelling Anamnia and poikilothermal Amniota there is a gap regarding expressly summer season alone in literature reports on autoradiographic studies in frog. The actual study suggests that the brain proliferative pattern in Rana bergeri collected in the wild in summer is intermediate between those previously observed in spring and autumn. This would seem to indicate a proliferative increase from spring to autumn. This pattern mainly appears in the forebrain, typically in the olfactory portion where the stem cells are identifi able as scattered “matrix“ cells in the ependyma and grey matter, and in the telencephalic district, where these cells are grouped as “matrix” areas in the well-known zonae germinativae dorsales and ventrales

Interaction between spring temperature-photoperiod and experimentally induced transient cold shock influencing proliferative activity in the brain of an adult terrestrial heterothermic vertebrate, Rana bergeri (Günther, 1986)

The seasonal thermal cycle and correlated variations in photoperiod exert antithetical influences on the proliferation of the reserve brain stem cells, which are mostly ependymal and sub-ependymal, of adult earth-dwelling heterothermic vertebrates upon deprivation of an encephalic area. Also, an induced sudden, transient thermal stress preceding surgical cerebral maiming increases or depresses the proliferation of these stand-by cells, depending on the season. In particular, the concomitance of spring temperature and photoperiod with a cold stimulus increases proliferation. To re-evaluate these findings, normal adults of Rana bergeri were exposed to a cold shock in spring time. The outlined patterns, as revealed by immunocytochemical detection of a proliferation-linked antigen, showed that those conditions affect only the forebrain, where immunoreactivity was identifiable in quiescent cells mostly located in peculiar telencephalic ependymal sites, known as zonae germinativae dorsales and ventrales, while the regions lying behind had no substantial proliferative response. These results may be due to the absence of further proliferative stimuli (surgical stress, cerebral ablation), so that only the stand-by cells in the encephalic areas more rich in such cells are activated to proliferate. The findings are in line with the subordinate position of Anurans as compared with Urodeles, which are the most gifted with spontaneous and experimentally induced reparative and regenerative capacity among vertebrates

Relationships between summer Thermal variations and cell proliferation in heterothermic vertebrates, as revealed by PCNA expression in the brain of adult Rana bergeri (Günther, 1986)

About the issue if the natural encephalic proliferative activities can be infl uenced by the seasonal (thermal and photoperiodic) cyclic fl uctuations in adult earth-dwelling Anamnia and poikilothermal Amniota there is a gap regarding expressly summer season alone in literature reports on autoradiographic studies in frog. The actual study suggests that the brain proliferative pattern in Rana bergeri collected in the wild in summer is intermediate between those previously observed in spring and autumn. This would seem to indicate a proliferative increase from spring to autumn. This pattern mainly appears in the forebrain, typically in the olfactory portion where the stem cells are identifi able as scattered “matrix“ cells in the ependyma and grey matter, and in the telencephalic district, where these cells are grouped as “matrix” areas in the well-known zonae germinativae dorsales and ventrales

New species of Dolichopoda Bolívar, 1880 (Orthoptera, Rhaphidophoridae) from the Aegean Islands of Andros, Paros and Kinaros (Greece)

In this paper two new species of Dolichopoda Bolívar, 1880 from the Cyclades islands of Andros and Paros and one from the Dodecanissos island of Kinaros, are described, increasing the total number of Greek species to 32. The new species from Paros (D. kikladica Di Russo & Rampini, n. sp.) and Kinaros (D. margiolis Di Russo & Rampini, n. sp.) show strong similarities with D. naxia Boudou-Saltet, 1972 from Naxos forming an homogenous group limited to the central Aegean islands. On the other hand the species D. christos-nifoni Di Russo & Rampini, n. sp. from Andros shows a combination of morphological characters that partly resemble characters found in Evvian Dolichopoda, and partly in species from the Cyclades. Relationships among these three new taxa and the other adjacent Dolichopoda species are discussed on the basis of the paleogeological and paleoclimatic events that shaped the present geography of the Aegean area

Relationships between seasonal (spring, summer, autumnal) thermal variations and cell proliferation in heterothermic vertebrates, as revealed by PCNA expression in the brain of adult Triturus carnifex

Inspired both by the literature reports and our previous findings on the question if a seasonal cycle alone, consisting of temperature and photoperiod variations, might impact on or activate natural proliferative fluctuations or unmask a latent spontaneous proliferative power in adult brain of poikilothermal Anamnia (fresh water, earth-dwelling) and Amniota (terrestrial), consequently allowing for encephalic reparative and even regenerative potentialities, an investigation has been carried on in normal adult brain of Triturus carnifex caught in nature in spring, summer, autumn. Cells immunostained for PCNA, i.e. cycling cells, were found scattered (“matrix cells”) in the olfactory territories, where they appeared scarce in spring, more frequent in summer, noticeable in autumn; also, immunostained cells were found clustered in “matrix areas”, also named zonae germinativae dorsales and ventrales, in the telencephalic hemispheres: few clusters in spring, an intermediate condition in summer, frequent cell groups in autumn. These results reveal an increasing trend in proliferation from spring, through summer, to autumn. This scenario was appreciable in the forebrain, mainly in the olfactory and telencephalic districts, which is the typical site of stem cells. Signs of potential proliferative activity are well appreciable in the urodele Amphibians, which are the best provided among vertebrates with reparative and regenerative power and possess the richest endowment of dormant cells susceptible to be recruited to proliferation

Proliferative events experimentally induced by transient cold shock in the brain of adult terrestrial heterothermic vertebrates: preliminary analysis of PCNA expression in Triturus carnifex

Experimental procedures used to investigate the persistence, location and abundance of scattered (“matrix cells”) and/or clustered (“matrix areas”) stem cells in the brain, responsible for proliferation in adult terrestrial heterothermic vertebrates have included an induced transient drop in body temperature in specimens subsequently deprived of encephalic areas. In a set of coordinated investigations focused on the influence of an exposure to a drastic thermally environment on these activities, we gave priority to Triturus carnifex, since there is a much larger amount of detailed, unequivocal experimental evidence available for this species than for other vertebrates of the same evolutionary level. In the present study, cold-shocked newts were examined after a stay at external temperature (the most suitable one based on previous experience) to allow the maximal expression of cerebral proliferation. In a qualitative evaluation, the brain of experimental specimens compared with that of normal individuals seemed not to show, contrary to expectations, more pronounced cell proliferation as assessed by Proliferat- ing Cell Nuclear Antigen immunolabelling of neural-like cells in the S phase of cell cycle. This discrepancy with previous reports from other authors may depend on having used cold stress alone, while other traumatic stimuli (operatory shock, encephalic injury) administered by the previous authors might have induced a greater number of cells to move from a stand-by condition to proliferation, allowing for reparative and/or regenerative phenomena

Relationships between summer thermal variations and cell proliferation in heterothermic vertebrates, as revealed by PCNA expression in the brain of adult Rana bergeri (Günther, 1986)

About the issue if the natural encephalic proliferative activities can be influenced by the seasonal (thermal and photoperiodic) cyclic fluctuations in adult earth-dwelling Anamnia and poikilothermal Amniota there is a gap regarding expressly summer season alone in literature reports on autoradiographic studies in frog. The actual study suggests that the brain proliferative pattern in Rana bergeri collected in the wild in summer is intermediate between those previously observed in spring and autumn. This would seem to indicate a proliferative increase from spring to autumn. This pattern mainly appears in the forebrain, typically in the olfactory portion where the stem cells are identifiable as scattered “matrix“ cells in the ependyma and grey matter, and in the telencephalic district, where these cells are grouped as “matrix” areas in the well-known zonae germinativae dorsales and ventrales

A genotoxicity study on Talitrus saltator (Crustacea, Amphipoda) exposed to lead and benzo(a)pyrene

Sandy beaches are ecosystems often subjected to a variety of pollution sources, including heavy metals and polycyclic aromatic hydrocarbons, largely due to improper human activities. The sandhopper Talitrus saltator s. l. (Montagu, 1808) typically lives on supralittoral shores where it plays an important ecological role. The purpose of this study was to investigate DNA damage levels on hemocytes of T. saltator by means of the Comet assay. Firstly, we tested the sensitivity and reproducibility of the Comet assay on hemocytes of T. saltator after in vitro exposure (1 h) to the genotoxicant methyl methanesulfonate (MMS). The data demonstrated a DNA damage (defined as % DNA tail) related to MMS exposure in a concentration-dependent manner. Next, we carried out the assay on hemocytes of T. saltator that were exposed in vivo (24 h and 7 days) to: a) lead (Pb), b) benzo(a)pyrene (B(a)P), c) mixtures of them. Our data on exposure to Pb or B(a)P showed DNA damage on the hemocytes of T. saltator in a concentration-dependent manner, but apparently with a non-synergistic effect of exposure to their mixtures. Our results provide a background for further studies in order to verify the applicability of Comet assay on T. saltator for assessing genotoxicity levels in sandy beaches subjected to pollutio

Does muscular activity related to vertical facial divergence influence the time needed for orthodontic extrusion of palatally impacted maxillary canines? A retrospective study

The aim of the present study was to evaluate if the different muscular activity correlated to different degrees of facial divergence has an effect on the time needed to extrude a palatally impacted maxillary canine. Twenty-six patients were retrospectively selected, all treated with a specific cantilever appliance that allows extrusion of the impacted canine applying a physiologic amount of force below 0.6 N in a predictable way. For all the patients, pre-treatment cephalometric tracings were used to evaluate facial divergence through the FMA angle, the angle between the maxillary and mandibular plane, and the angles between the occlusal plane and either the maxillary and mandibular plane. Linear bivariate regression was calculated to evaluate if facial divergence can predict the time needed for canine extrusion. The linear regression model was not able to predict extrusion time from variables explaining the facial divergence. Palatally impacted maxillary canines can be treated with the application of physiologic extrusion force regardless of patients? facial divergence and muscular activity

Longitudinal effects of rapid maxillary expansion on masticatory muscles activity

To investigate the modifications induced by rapid maxillary expansion (RME) on the electromyographic (EMG) activities of the anterior temporal and superficial masseter muscles, in patients without pre-treatment EMG alterations. Twenty-one patients with unilateral posterior cross-bite selected from the orthodontic department of the University of L?Aquila (Italy), were enrolled. There was no control group in this study since each subject acted as a control of her/himself. Two surface EMG recordings were taken: T0 (before RME) and at T1 (3 month after the end of expansion). To verify the neuromuscular equilibrium, the EMG activities of both right and left masseter and anterior temporal muscles were recorded during a test of maximum clench. EMG indexes were compared by paired Student?s t-test. In both occasions, all indices showed a good symmetry between the right and left side masticatory muscles. No statistically significant differences were found between the two recordings. In children without pre-treatment EMG alterations, no variations in standardized muscular activity after RME were found. The treatment did not alter the equilibrium of the masseter and temporal muscles