53 research outputs found
DISTRIBUTION OF PHOLETER GASTROPHILUS (DIGENEA) WITHIN THE STOMACH OF FOUR ODONTOCETE SPECIES: THE ROLE OF THE DIET AND DIGESTIVE PHYSIOLOGY OF HOSTS
No full textWe compared the distribution of the digenean Pholeter gastrophilus in the stomach of 27 harbour porpoises, Phocoena phocoena, 27 striped dolphins, Stenella coeruleoalba, 18 bottlenose dolphins, Tursiops truncatus, and 100 long-finned pilot whales, Globicephala melas. The stomach of these species is composed of 4 chambers of different size, structure and function. In all species, P. gastrophilus was largely restricted to the glandular region of the stomach, but the parasite tended to favour the fundic chamber in bottlenose dolphins and harbour porpoises, the pyloric chamber in pilot whales, and none in striped dolphins. However, predictability at infrapopulation level was generally low, suggesting a weak preference of P. gastrophilus for any of the chambers. Three hypotheses were tested to investigate a common cause for the distribution of P. gastrophilus in all host species, namely, colonization of chambers was (1) sequential, (2) dependent on chamber size, or (3) dependent on the passage time of food through the whole stomach. The latter hypothesis was indirectly tested by assuming, based on previous evidence from other vertebrates, that the greater the size of the stomach and/or the energy content of prey, the greater the delay of food passage. We found no compelling evidence that chamber colonization was sequential, or related to chamber size in any species. However, the distribution of P. gastrophilus was significantly more anteriad when the host species had larger stomachs and, particularly, when hosts fed on prey with higher caloric content. Accordingly, the stomach distribution of P. gastrophilus at this scale seems to be passively driven by features of the diet and digestive physiology of each host species. This study provides a general framework to formulate null hypotheses in future studies on microhabitat choice by parasites
Parassiti dei cetacei del Mediterraneo. In: Mammiferi marini del Mediterraneo : storia naturale, biologia, anatomia, patologia, parassitologia
No full textIllustra i principali agenti parassitari che colpiscono i cetacei. Su Supporto informatic
An experimental procedure to perform mechanical characterization of small-sized bone specimens from thin femoral cortical wall
No full textThe cortical shell of the femoral neck plays a role in determining the overall neck strength. However, there is a lack of knowledge about the mechanical properties of cortical tissue of the femoral neck due to challenges in implementing accurate testing protocols for the thin shell. Indeed, mechanical properties are commonly derived from mechanical testing performed on tissue samples extracted from the femoral diaphysis, i.e. assuming tissue homogeneity along the femur. The aim of this work was to set up a reliable methodology to determine mechanical properties of bone samples extracted from thin cortical shell of the femoral neck. A three-point bending test was used to determine elastic and post-elastic properties of cortical bone samples extracted from the inferior and superior femoral neck. An optical system was used to monitor the sample deflection. Accuracy was preliminarily evaluated by determining the elastic modulus of an aluminium alloy. A good intra- and inter-sample variability was found on determining aluminium elastic modulus: 1.6% and 3.6%, respectively. Additionally, aluminium elastic modulus value was underestimated by less than 1%. A pilot trial was performed on a human femoral neck to assess the procedure feasibility. A total of 22 samples were extracted from the inferior and superior femoral neck and successfully tested. Preliminary results suggest that mechanical properties of cortical bone tissue extracted from human femoral neck might be side dependent, the superior tissue seems to exhibit better mechanical properties than the inferior one, at least in terms of yield stress and maximum strain. This supposedly different mechanical competence must be further investigated. The proposed procedure makes it feasible to carry out such studies
IgG3 subclass: A possible trigger of mixed cryoglobulin cascade in hepatitis C virus chronic infection
No full textHCV is a hepatotropic and lymphotropic virus and is the most frequent cause of "benign" mono-oligoclonal B-lymphocyte proliferation, observed in mixed cryoglobulinemia (MC). The study aims to investigate the presence, prevalence and characteristics of the subclasses of cryoglobulins in HCV-patients to look for a relationship with MC. Fifty HCV-infected patients with cryoglobulins were enrolled. IgG subclasses were characterized in cryoprecipitate, and serum IgG and IgM Rheumatoid Factor (RF) were determined. Patients were stratified into two subgroups according to the presence of IgG3 subclass. Differences were observed in supernatant IgM, IgG3-positive and IgG3-negative patients with a higher IgM concentration in the IgG3-negative cohort (p=0.03). Higher IgM-RF was detected in the IgG3-negative group (p=0.01). IgG3-positive group showed higher IgG-RF compared to the IgG3-negative group (p<0.0001). IgG3-negative/monoclonal-IgM patients had higher cryocrit compared to IgG3-negative/polyclonal-IgM patients (p<0.01). C4 levels were higher in the polyclonal-IgM group compared to monoclonal-IgM group (p<0.01). We speculate that cryoglobulins are part of a progressive clonal selection process in which, B-cells are stimulated to produce oligoclonal IgG3 with RF activity. The persistence of the antigenic stimulus elicits the production of polyclonal IgM-RF and subsequently the formation of oligoclonal IgG/polyclonal IgM containing cryoglobulins. In the last stage, a monoclonal IgM-RF clone is formed which may coexist with a monoclonal IgG3-RF clone
Hepatitis C virus infection in the immunocompromised host: a complex scenario with variable clinical impact
No full textAbstract The relationship between Hepatitis C Virus (HCV) infection and immunosuppression is complex and multifaceted. Although HCV-related hepatocytolysis is classically interpreted as secondary to the attack by cytotoxic T lymphocytes against infected cells, the liver disease is usually exacerbated and more rapidly evolutive in immunosuppressed patients. This generally occurs during the immunosuppression state, and not at the reconstitution of the host response after immunosuppressive therapy discontinuation. The field of immunosuppression and HCV infection is complicated both by the different outcome observed in different situations and/or by contrasting data obtained in the same conditions, with several still unanswered questions, such as the opportunity to modify treatment schedules in the setting of post-transplant follow-up. The complexity of this field is further complicated by the intrinsic tendency of HCV infection in itself to lead to disorders of the immune system. This review will briefly outline the current knowledge about the pathogenesis of both hepatic and extrahepatic HCV-related disorders and the principal available data concerning HCV infection in a condition of impairment of the immune system. Attention will be especially focused on some conditions - liver or kidney transplantation, the use of biologic drugs and cancer chemotherapy - for which more abundant and interesting data exist.</p
BAFF, BAFF promoter and BAFF receptor allelic variants in HCV-related Mixed Cryoglobulinemia and Non Hodgkin's Lymphoma
No full textMIR-17/92 EXPRESSION PATTERN: A MOLECULAR SIGNATURE OF HCV-RELATED MIXED CRYOGLOBULINEMIA
No full textIntroduction: HCV infection is closely related to the development of lymphoproliferative disorders (LPDs), mainly mixed cryoglobulinemia (MC) and B-cell lymphoma. Modification of the expression levels of specific microRNAs (miRNAs) has been associated with different autoimmune and/or LPDs. In particular, the endogenous miR-17/92 cluster is very often amplified in cancer and in autoimmunity. Scarce data exist about the modifications of miRNA expression levels in HCV-related LPDs.
Aim: To evaluate the modifications of miR-17/92 cluster levels in HCV-positive patients with and without MC.
Methods: miR-17/92 cluster expression levels were evaluated by Real Time PCR in PBMC samples from 79 HCV patients: 34 without LPD [HCV] and 45 with MC [HCV-MC]; among the 45 MC patients were included 20 patients who experienced a sustained virological and clinical response after antiviral treatment and of which pre and post therapy sampling was available. Relative expression levels of all the members of the miR-17/92 cluster (namely, miR-17, miR-18a, miR-19a, miR-19b, miR-20a and miR-92a) were evaluated with the 2−ΔΔCt method, using miR-let-7d as housekeeping.
Results: All the members of the miR-17/92 cluster were highly upregulated in PBMCs from HCV-MC patients (p < 0.001) when compared to HCV group. A restoration of miRNAs levels was observed in the samples taken after viral eradication (miR-17, miR-18a, miR-19a, miR-19b, miR-20a, p < 0.001 and miR-92a, p < 0.05, when compared with pre-treatment levels). Regarding miR-20a, the levels in samples taken after HCV eradication continued to be significantly higher than in controls (HCV patients) (p < 0.05), in spite of the sudden fall observed after therapy.
Conclusions: This study shows that the pattern of miRNA-17/92 cluster is modified in PBMC from HCV patients with MC. The sudden restoration of these values of expression in patients achieving a sustained virological and clinical response after antiviral treatment, strongly suggests that miR-17/92 cluster plays a key role in the pathogenesis of MC
Dependence of mechanical compressive strength on local variations in microarchitecture in cancellous bone of proximal human femur
No full textHuman cancellous bone is a heterogeneous material. Despite this, most of the published studies report correlations between mechanical properties and morphometric parameters averaged on the whole specimen. This work investigated whether local variations in morphometric parameters were linked to the localized failure regions of cancellous bone. Additionally, it was examined whether local values of morphometric parameters can predict the ultimate stress better than the average bone volume fraction (BV/TV). Cylindrical cancellous bone specimens extracted along the primary compressive group of human femoral heads were studied. These were microCT-imaged to assess the morphometric parameters, compressed to determine the ultimate stress, and rescanned by microCT to visualize the failure region. Failure involved slightly less than half of the free height of the specimens. Significant differences were found in the morphometric parameters calculated in the failure and in the non-failure regions. The cross-sections containing minimum BV/TV values were those most often located inside the failure region (83%, p<0.001). Regression analysis confirmed that variations in BV/TV best describe variations in ultimate stress (R2=0.84) out of the averaged morphometric parameters. The prediction of ultimate stress increased when minimum or maximum values of the morphometric parameters were taken, with the highest prediction found by considering the minimum BV/TV (R2=0.95). In conclusion, due to the heterogeneity of cancellous bone, there may exist regions characterized by a different microarchitecture, where the bone is weaker and consequently is more likely to fail. These regions mostly contain minimum values in BV/TV, which were found to predict ultimate stress better than average BV/TV
A serum metabolomic analysis of HCV-infected patients successfully treated with IFN-free DAA regimens
No full textHCV infects about 170 million of subjects worldwide. The virus has a high propensity to persist in the host, leading to cirrhosis and liver cancer. Metabolomics is the study of metabolic changes in biological systems and may identify specific profiles associated with subtle alterations induced by diseases. Few studies are available on metabolitic changes in liver injuries, and since none of which was focused on HCV-infected patients before and after reaching a SVR following treatment with direct acting antivirals (DAAs), the aim of this study was to perform a serum metabolomics analysis in this setting Sera were collected from 52 HCV patients (18 men, mean age 65±9,7) successfully undergoing different IFN-free DAA regimens, before therapy (baseline) and at post-treatment week 12 (SVR12). HCV genotype was 1a/1b in 70%, 2a/2c in 23%, 3 in 4.7% and 4 in 2.3%. METAVIR score indicated F3-F4 score in 55% of patients, the remaining 45% had F0-F2 We also analyzed a small group of 12 sera from healthy subjects in order to localize them in the PLS plot respect to baseline and SVR12 as a preliminary negative control for both groups. Samples were analyzed using proton nuclear magnetic resonance spectroscopy (1H-NMR). Partial Least Squares (PLS) and the canonical analysis (CA) were applied, demonstrating a significant pair-wise discrimination (96% of accuracy) for the two time-points of each patient and highlighting a metabolic shift Several metabolites with unequivocal assignment (i e amino acids, organic acids, creatine, creatinine, lactate and choline) differed comparing baseline with SVR12. Baseline featured higher level of formate and acetate (p<0.05) and methionine was higher in SVR12 (p<0.05). Preliminary analysis revealed also a progressive nearing of SVR12 to the healthy fingerprint. The serum metabolomic analysis of pre- and post-treatment samples showed remarkable profile changes from baseline to SVR12. We found variations, with opposite directions, in formate (produced in adults only by hepatocytes) and methionine. These metabolites take part in biochemical ways (i e glucose metabolism) also involving acetate and other amino acids, going through the synthesis of folates These alterations could be implied in the metabolic impairment previously observed in chronically infected HCV-patients. Also, since methionine is the major source of methyl groups, an understanding of its variation, could reveal important dysfunctions in liver essential pathways requiring methylation (i e epigenetic regulation of DNA) in HCV-related chronic infection
Deregulation of microRNA expression in peripheral blood mononuclear cells from patients with HCV-related malignancies
No full textBackground and aim: Hepatocellular carcinoma is one of the major causes of death due to cancer worldwide, and its association with hepatitis C virus infection has been definitively established. Hepatitis C virus is also involved in the pathogenesis of non-Hodgkin’s lymphoma. This is the only virus infecting humans that is able to induce two different malignancies. We analyzed the expression levels of a panel of microRNA in peripheral blood mononuclear cells of patients with hepatitis C virus-related malignancies in order to find a disease-associated deregulation and identify specific biomarkers. Methods: We tested peripheral blood mononuclear cells isolated from patients with hepatocellular carcinoma, non-Hodgkin’s lymphoma, hepatitis C virus without malignancies and healthy subjects for a panel of microRNA selected on the basis of previous studies. MicroRNA expression was evaluated by real-time PCR. Results: Our results showed an upregulation of miRNA-21 and downregulation of miRNA-26b in hepatocellular carcinoma and non-Hodgkin’s lymphoma patients compared to controls (p < 0.001). Deregulation of miRNA-16 and miRNA-155 was limited to lymphoma patients. Conclusions: This study shows that some microRNAs are differently expressed in peripheral blood mononuclear cells from hepatitis C virus patients who develop hepatocellular carcinoma or lymphoma, while others share a common behavior. Thus, analysis of the expression of microRNAs could be a noninvasive marker of hepatitis C virus-related carcinogenesis. This analysis could be a suitable tool for identifying the existence of a malignancy and also discriminating between these two hepatitis C virus-related cancers
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