PubMed Health⌕ Search

Biomedical subjects

M Ferretti

Publications and source records attributed to M Ferretti.

At least 19 recordsLinked to original sources
PubMed2006

Measuring, modelling and testing ozone exposure, flux and effects on vegetation in southern European conditions--what does not work? A review from Italy.

Ozone (O3) exposure at Italian background sites exceeds UN/ECE concentration-based critical levels (CLe(c)), if expressed in terms of AOT40. Yet the occurrence of adverse effects of O3 on forests and crops is controversial. Possible reasons include (i) ability of response indicators to provide an unbiased estimate of O3 effects, (ii) setting of current CLe(c) in terms of cut-off value and accumulation level, (iii) response functions adopted to infer a critical level, (iv) environmental limitation to O3 uptake and (v) inherent characteristics of Mediterranean vegetation. In particular, the two latter points suggest that critical levels based on accumulated stomatal flux (CLe(f)) can be a better predictor of O3 risk than CLe(c). While this concept is largely acknowledged, a number of factors may limit its applicability for routine monitoring. This paper reviews levels, uptake and vegetation response to O3 in Italy over recent years to discuss value, uncertainty and feasibility of different approaches to risk assessment.

Crops, Agricultural↗
PubMed2006

Different skeletal regional response to continuous brain infusion of leptin in the rat.

This study was designed to evaluate whether or not continuous intracerebroventricular infusion of leptin (1.5 microg/rat/24 h, for 28 days) produced different regional response on the skeleton of growing rats. Leptin reduce the accretion of total femoral bone mineral content (BMC) and density (BMD). This effect was related to a reduction of metaphyseal femur as no changes were detected in the diaphysis. Despite the reduced accretion in the volumetric of both femur and tibia compared to controls, leptin had no significant effects on the lumbar vertebrae. Urine deoxypyrydinoline and serum osteocalcin remained more elevated in the leptin-treated group as compared to controls. The results demonstrate that long-term central infusion of leptin activates bone remodeling with a negative balance. Leptin induces distinct responses in the different structure of bone and in the axial and appendicular skeleton.

Animals↗
PubMed2004

Air pollution and forest health: toward new monitoring concepts.

It is estimated that 49% of forests (17 million km(2)) will be exposed to damaging concentrations of tropospheric O(3) by 2100. Global forest area at risk from S deposition may reach 5.9 million km(2) by 2050, despite SO(2) emission reductions of 48% in North America and 25% in Europe. Although SO(2) levels have decreased, emissions of NO(x) are little changed, or have increased slightly. In some regions, the molar SO(4)/NO(3) ratio in precipitation has switched from 2/1 to near 1/1 during the past two decades. Coincidentally, pattern shifts in precipitation and temperature are evident. A number of reports suggest that forests are being affected by air pollution. Yet, the extent to which such effects occur is uncertain, despite the efforts dedicated to monitoring forests. Routine monitoring programmes provide a huge amount of data. Yet in many cases, these data do not fit the conceptual and statistical requirements for detecting status and trends of forest health, nor for cause-effect research. There is a clear need for a re-thinking of monitoring strategies.

Air Pollutants↗
PubMed2004

Reliability of different sampling densities for estimating and mapping lichen diversity in biomonitoring studies.

Sampling requirements related to lichen biomonitoring include optimal sampling density for obtaining precise and unbiased estimates of population parameters and maps of known reliability. Two available datasets on a sub-national scale in Italy were used to determine a cost-effective sampling density to be adopted in medium-to-large-scale biomonitoring studies. As expected, the relative error in the mean Lichen Biodiversity (Italian acronym: BL) values and the error associated with the interpolation of BL values for (unmeasured) grid cells increased as the sampling density decreased. However, the increase in size of the error was not linear and even a considerable reduction (up to 50%) in the original sampling effort led to a far smaller increase in errors in the mean estimates (<6%) and in mapping (<18%) as compared with the original sampling densities. A reduction in the sampling effort can result in considerable savings of resources, which can then be used for a more detailed investigation of potentially problematic areas. It is, however, necessary to decide the acceptable level of precision at the design stage of the investigation, so as to select the proper sampling density.

Air Pollutants↗
PubMed2004

In vivo leptin expression in cartilage and bone cells of growing rats and adult humans.

The present investigation was carried out to analyse, immunohistochemically, in vivo leptin expression in cartilage and bone cells, the latter restricted to the elements of the osteogenic system (stromal cells, osteoblasts, osteocytes, bone lining cells). Observations were performed on the first lumbar vertebra, tibia and femur of four rats and on the humerus, femur and acromion of four patients. Histological sections of paraffin-embedded bone samples were immunostained using antibody to leptin. The results showed that, in growing rat bone, leptin is expressed in chondrocytes and stromal cells, but not in osteoblasts; bone lining cells were not found in the microscopic fields examined. In adult human bone, leptin is expressed in chondrocytes, stromal cells and bone lining cells; osteoblasts were not found in the microscopic fields examined. Osteocytes were found to be leptin positive only occasionally and focally in both rat and human bone. The in vivo findings reported show, for the first time, that leptin appears to be expressed only in the cells of the osteogenic lineage (stromal cells, bone lining cells, osteocytes) that, with respect to osteoblasts, are permanent and inactive, i.e. in those cells that according to our terminology constitute the bone basic cellular system (BBCS). Because the BBCS seems to be primarily involved in sensing and integrating mechanical strains and biochemical factors and then in triggering and driving bone formation and/or bone resorption, it appears that leptin seems to be mainly involved in modulating the initial phases of bone modelling and remodelling processes.

Acromion↗
PubMed2003

Assessment of ozone visible symptoms in the field: perspectives of quality control.

The second UN/ECE ICP-Forests Intercalibration Course on the Assessment of Ozone Injury on European Tree Species was carried out in August 2001 at Lattecaldo (Canton Ticino, CH) and Moggio (Lombardy, I). Forty-eight experts from several European countries participated in the exercises and assessed visible symptoms of ozone injury both in open-top chambers (OTC) (Lattecaldo) and under open field (Moggio) conditions. Evaluation of the results indicated a large variability among the teams and call for adequate training of the observers prior to symptom assessment for quality assurance purposes. Highest variability was found for the species developing unclear symptoms which could be confused with senescence processes; such species should not be used in the field. The authors provide suggestions to improve the reliability of the ozone injury assessment on forest plant species.

Air Pollutants↗
PubMed2002

Towards a long-term integrated monitoring programme in Europe: network design in theory and practice.

Long-term integrated monitoring is an important approach for investigating, detecting and predicing the effects of environmental changes. Currently. European freshwaters, glaciers, forests and other natural and semi-natural ecosystems and habitats are monitored by a number of networks established by different organisations. However, many monitoring programmes have a narrow focus (e.g. targeting individual ecosystems) and most have different measurement protocols and sampling design. This has resulted in poor integration of ecosystem monitoring at a European level, leading to some overlapping of efforts and a lack of harmonised data to inform policy decisions. The need for a consistent pan-European long-term integrated monitoring of terrestrial systems programme is recognised in the scientific community. However, the design of such a system can be problematic, not least because of the constraints imposed by the need to make maximum use of existing sites and networks. Based on the outcomes of the NoLIMITS project (Networking of Long-term Integrated Monitoring in Terrestrial Systems). this article reviews issues that should be addressed in designing a programme based on existing monitoring sites and networks. Four major design issues are considered: (i) users' requirements, (ii) the need to address multiple objectives, (iii) role of existing sites and (iv) operational aspects.

Altitude↗
PubMed2002

Bone as an ion exchange system: evidence for a link between mechanotransduction and metabolic needs.

To detect whether the mutual interaction occurring between the osteocytes-bone lining cells system (OBLCS) and the bone extracellular fluid (BECF) is affected by load through a modification of the BECF-extracellular fluid (ECF; systemic extracellular fluid) gradient, mice metatarsal bones immersed in ECF were subjected ex vivo to a 2-min cyclic axial load of different amplitudes and frequencies. The electric (ionic) currents at the bone surface were measured by a vibrating probe after having exposed BECF to ECF through a transcortical hole. The application of different loads and different frequencies increased the ionic current in a dose-dependent manner. The postload current density subsequently decayed following an exponential pattern. Postload increment's amplitude and decay were dependent on bone viability. Dummy and static loads did not induce current density modifications. Because BECF is perturbed by loading, it is conceivable that OBLCS tends to restore BECF preload conditions by controlling ion fluxes at the bone-plasma interface to fulfill metabolic needs. Because the electric current reflects the integrated activity of OBLCS, its evaluation in transgenic mice engineered to possess genetic lesions in channels or matrix constituents could be helpful in the characterization of the mechanical and metabolic functions of bone.

Animals↗
PubMed2001

Monitoring and biomonitoring of surface ozone in Florence, Italy.

An ambient air study was conducted in the city of Florence, Italy, in the summer 1996. Tropospheric ozone was continuously monitored with automatic analyzers in three stations, two located in the urban area and one in the hilly surroundings (Settignano). A biomonitoring campaign based on the tobacco cv. Bel-W3 plants was performed in the same area. The highest values were constantly recorded in the Settignano station. The highest 1-hour mean recorded was 197 nl/l; the accumulated exposure over a threshold of 40 nl/l (AOT40) was well above the critical levels standards for protection of the vegetation. A consistent temporal variation was observed and July proved to be the month with the highest ozone levels. Cumulative frequency distribution of ozone maximum daily concentrations exhibited a good fitting to log-normality. No 'week-end' effect was observed. Biomonitoring data were in good agreement with chemico-physical ones.

Air Pollutants↗
PubMed2001

Osteocyte-osteoclast morphological relationships and the putative role of osteocytes in bone remodeling.

An osteocyte lacunae differential count under the light microscope (LM) (1-lacunae with live osteocytes, 2-empty lacunae and lacunae with degenerating osteocytes) was carried out outside the reversal lines of osteonic lamellar bone from various mammals and man to evaluate the possibility of osteocyte survival where osteoclast resorption had occurred. The polarized light microscope (PLM) was used to establish the curvature of bony lamellae outside the convexity of reversal lines: concave lamellae indicate osteocytes reabsorbed on their vascular side where they radiate long vascular dendrites; convex lamellae indicate bone resorption on the osteocyte mineral side, radiating short dendrites. In all samples it was found that: a) about 60% of osteocytes outside the reversal lines were live; b) the percentage of alive osteocytes close to reversal lines is higher when they are attacked on their mineral side. The present data support our view that surviving osteocytes, particularly those attacked from their mineral side, might intervene in the final phase of bone resorption (osteoclast inhibition?). The fact that under the transmission electron microscope (TEM) intercellular contacts were never observed between osteocytes and osteoclasts indicates that if a modulation should occur between these two cellular types it could take place by a paracrine route only. The putative role of the cells of the osteogenic system, particularly osteocytes, in the bone remodeling cycle is also discussed.

Journal Article↗
PubMed1998

Heterotrimeric G proteins physically associated with the lipopolysaccharide receptor CD14 modulate both in vivo and in vitro responses to lipopolysaccharide.

Septic shock induced by lipopolysaccharide (LPS) triggering of cytokine production from monocytes/macrophages is a major cause of morbidity and mortality. The major monocyte/macrophage LPS receptor is the glycosylphosphatidylinositol (GPI)-anchored glycoprotein CD14. Here we demonstrate that CD14 coimmunoprecipitates with Gi/Go heterotrimeric G proteins. Furthermore, we demonstrate that heterotrimeric G proteins specifically regulate CD14-mediated, LPS-induced mitogen-activated protein kinase (MAPK) activation and cytokine production in normal human monocytes and cultured cells. We report here that a G protein binding peptide protects rats from LPS-induced mortality, suggesting a functional linkage between a GPI-anchored receptor and the intracellular signaling molecules with which it is physically associated.

Animals↗
PubMed1998

Comparison of oral with rectal mesalazine in the treatment of ulcerative proctitis.

PURPOSE: The aim of our study was to compare the efficacy and safety of oral mesalazine with mesalazine suppositories in patients with active ulcerative proctitis. PATIENTS AND METHODS: A four-week, randomized, single-blind trial was performed in 58 patients with active, histologically confirmed ulcerative proctitis (< or = 15 cm) to evaluate the efficacy and safety of oral 800-mg mesalazine tablets taken three times per day (n = 29) compared with 400 mg of mesalazine suppositories administered three times per day (n = 29). Patients were evaluated at study entry and after two and four weeks. Efficacy evaluations included a disease activity index, which represents a score with four variables: stools frequency, rectal bleeding, mucosal appearance, and physician's assessment of disease severity. Histologic activity was also assessed at study entry and after two and four weeks in accordance with the criteria by Truelove and Richard. Safety assessment included clinical laboratory parameters and adverse event reports. RESULTS: There were no significant differences with regard to baseline comparisons of demographics and severity between the two treatment groups. Improvement in mean disease activity index score was significantly greater with suppositories compared with oral mesalazine, both at two-week and four-week visits (mean disease activity index scores at baseline, two, and four weeks: suppositories = 7.7, 2.59, and 1.48; tablets = 7.42, 5.72, and 3.48, respectively (P < 0.001)). The rate of histologic remission was significantly greater with suppositories compared with tablets both at two and four weeks (P < 0.01). There were no significant differences in adverse events or clinical laboratory results between treatment groups. CONCLUSIONS: Results of this study indicate that treatment with mesalazine suppositories produces earlier and significantly better results than oral mesalazine in the treatment of active ulcerative proctitis.

Administration, Oral↗
PubMed1998

Osteocyte-bone lining cell system at the origin of steady ionic current in damaged amphibian bone.

A wound-generated steady electric current was measured by a two-dimensional vibrating probe system in the metatarsal bones of 22 adult frogs (Xenopus laevis) placed in amphibian Ringer. Inward currents were recorded entering a micrometric hole drilled through the cortex at middiaphyseal level. These steady state currents (mean +/- SD 8.50 +/- 2.77 microA/cm2) last approximately 2 hours, were dependent on the presence of sodium in the incubation medium, were no more detectable after fixation, and were reduced to background level when the cell membranes were solubilized. These results agree with previous recordings of metatarsal bones of weanling mice, under identical conditions. Both results suggest that the measured ionic currents have a cellular origin. Metatarsal bones of adult amphibian were purposely selected for this study because, unlike mammalian bones, their shafts are avascular and only contain an osteocyte-bone lining cell system, as documented by scanning and transmission electron observations. Thus, unlike the data from previous investigations on mammals, the results succeeded in giving the first convincing evidence that the osteocyte-bone lining cell system is the origin of damage-generated ionic currents. As damage exposes bone ionic compartment to plasma, damage-generated ionic currents are representative of ion fluxes at bone plasma interface, and cells at the origin of the current generate the driving force of such fluxes. By demonstrating that osteocytes and bone lining cells are at the origin of the current, this study suggests that the osteocyte-bone lining cell system, though operating as a cellular membrane partition, regulates ionic flow between bone and plasma. Since strain-related adaptive remodeling could also depend on ionic characteristics and flow of the bone fluid through the osteocyte lacuno-canalicular network, the results reported here support the view that osteocyte and bone lining cells may constitute a functional syncytium involved in mineral homeostasis as well as in bone adaptation to mechanical loading.

Animals↗
PubMed1998

Stromal cell structure and relationships in perimedullary spaces of chick embryo shaft bones.

Structure and relationships of stromal cells were studied by light (LM) and transmission electron microscopy (TEM) in the perimedullary spaces that form the growing cortex of the chick embryo tibia. Observation under LM showed that in all perimedullary spaces the interstices between the cells carpeting the bone surface and the endothelial lining contain stromal cells surrounded by an amorphous matrix. Two types of stromal cells were distinguished: stellate and spindle-shaped. All stromal cells are alkaline phosphatase-positive. TEM showed that both types of stromal cells have cytoplasmic processes of various length and calibre, coming into contact with each other as well as with endothelial cells and osteoblasts or bone lining cells. Capillaries were found to have a continuous endothelial lining; occasionally endothelial cells radiate cytoplasmic processes towards stromal cells. Along all the above-mentioned cellular contacts adherens and/or gap junctions were often observed. The results of the present study, together with our previous findings on osteoblast-osteocyte relationships, show that the cells of the osteogenic lineage form a continuous protoplasmic network that extends from the osteocytes to the vascular endothelium, passing through osteoblasts (or bone lining cells) and stromal cells. The occurrence of gap junctions among this cytoplasmic network, namely of junctions enabling metabolic and electric coupling, indicates that it forms a functional syncytium, suggesting the hypothesis that the activity of the cells pertaining to the osteogenic lineage might be regulated not only by diffusion (volume transmission) through the intercellular fluids of systemic (hormones) and local factors (cytokines, etc.) but also by signals issued through the cytoplasmic network of the osteogenic cells (wiring transmission).

Alkaline Phosphatase↗
PubMed1998

Air pollution, forest condition and forest decline in Southern Europe: an overview.

Over the last decades much of the work on the impact of air pollution on forests in Europe has concentrated on central and northern countries. The southern part of Europe has received far less attention, although air pollutants-especially the photochemical ones-can reach concentrations likely to have adverse effects on forest vegetation. Although international forest condition surveys present serious problems where data consistency is concerned, they reveal considerable year-by-year species-specific fluctuations rather than a large-scale forest decline. Cases of obvious decline related to environmental factors are well circumscribed: (1) the deterioration of some coastal forests due to the action of polluted seaspray; (2) the deterioration of reforestation projects, especially conifers, mainly due to the poor ecological compatibility between species and site; and (3) the decline of deciduous oaks in southern Italy and of evergreen oaks in the Iberian peninsula apparently due to the interaction of climate stresses and pests and diseases. However, besides obvious deterioration, changes in environmental factors can provoke situations of more subtle stress. The most sensitive stands are Mediterranean conifer forests and mesophile forests of the Mediterranean-montane plane growing at the edges of the natural ecological distribution. Evergreen sclerophyllous forests appear less sensitive to variations in climatic parameters, since they can adapt quite well to both drought and the action of UV-B rays. Several experiments were carried out to test the sensitivity of Mediterranean forest species to air pollutants. Most of those experiments used seedlings of different species treated with pollutant concentrations too high to be realistic, so it is difficult to derive adequate information on the response of adult trees in field conditions. Ozone has been proved to cause foliar injury in a variety of native forest species in different Southern European countries, while the effects of other pollutants (e.g. nitrogen, sulphur, acidic deposition) are less obvious and likely to be very localized. In the case of ozone, visible symptoms were almost completely missed by large-scale surveys and-at the same time-non-visible symptoms are suspected to be even more widespread than the visible ones. Owing to this and to the complex relationships existing between species sensitivity, ozone exposure and doses, length of the vegetative periods, influence of climatic and edaphic condition on the tree's response, the impacted areas are yet to be identified. Therefore, the large-scale impact of air pollutants on the forests of Southern Europe remains largely unknown, until more specific investigations are carried out.

Journal Article↗
PubMed1997

Intracolonic release of nitric oxide during trinitrobenzene sulfonic acid rat colitis.

Nitric oxide is thought to play an important role in modulating the inflammatory process. Recently an increase in the inducible form of nitric oxide synthase (iNOS) has been found in the rat trinitrobenzene sulfonic acid model of experimental colitis, and inhibition of nitric oxide synthase activity resulted in an amelioration of tissue injury. The aim of our study was to evaluate in vivo intracolonic release of nitric oxide in this model of colitis. Experimental colitis was induced in male Sprague-Dawley rats by a single intracolonic administration of trinitrobenzene sulfonic acid. Nitrite levels were determined in rectal dialysates by HPLC. The tissue myeloperoxidase and iNOS and the luminal leukotriene B4 were also measured. Nitrite levels were significantly increased in rectal dialysates during colitis and correlated significantly with tissue myeloperoxidase and iNOS activity. The correlation between nitrite dialysate levels and wall iNOS activity confirms that nitrite in dialysates is produced by inflammatory cells and not by colonic bacterial flora. Determination of nitrite levels in rectal dialysates seems a valuable method to monitor colonic inflammation in rat trinitrobenzene sulfonic acid colitis.

Animals↗