Cell proliferation rates and fibronectin arrangement as parameters for biocompatibility evaluation of dental metal alloys in vitro

A short-term (72-96 hours) biocompatibility evaluation in vitro of four single phase dental metal alloys was conducted by determining cell proliferation rates correlated to the organization of the extracellular matrix protein fibronectin in human fibroblast cultures. Immunocytochemical methods were performed to detect both cell proliferation rates by 5-bromodeoxyuridine (BrdU) incorporation, and fibronectin arrangement, i.e., diffuse in the extracellular matrix, organized in fibrils or in focal adhesions. We showed that cell proliferation rates were related to fibronectin expression. In particular, a higher percentage of cells in the S-phase were related to a predominance of fibronectin organized both in fibrils and in focal adhesions. The alloy with the highest Au content seemed the most biocompatible among those tested, since it behaved in a very similar manner to the controls. On the contrary, fibroblasts exposed to the alloy with the highest percentage of Ag had the most different behavior as compared to the controls. We can assume that a correlation exists between fibronectin organization and the percentage of BrdU-positive cells and that these parameters are varying with the different metal composition of the alloys. The observation of fibronectin arrangement together with cell proliferation rates could be considered a useful tool to determine the biocompatibility of these biomaterials.     

Differential contribution of Ih to the integration of excitatory synaptic inputs in substantia nigra pars compacta and ventral tegmental area dopaminergic neurons

The selective vulnerability of substantia nigra pars compacta (SNc) dopaminergic (DA) neurons is an enigmatic trait of Parkinson's disease (PD), especially if compared to the remarkable resistance of closely related DA neurons in the neighboring ventral tegmental area (VTA). Overall evidence indicates that specific electrophysiological, metabolic and molecular factors underlie SNc vulnerability, although many pieces of the puzzle are still missing. In this respect, we recently demonstrated that 1‐methyl‐4‐phenylpyridinium (MPP+), the active metabolite of the parkinsonizing toxin 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP), alters the electrophysiological properties of SNc DA neurons in vitro by inhibiting the hyperpolarization‐activated current (Ih). Here, we present an electrophysiological investigation of the functional role of Ih in the integration of synaptic inputs in identified SNc and VTA DA neurons, comparatively, in acute midbrain slices from TH‐GFP mice. We show that pharmacological suppression of Ih increases the amplitude and decay time of excitatory postsynaptic potentials, leading to temporal summation of multiple excitatory potentials at somatic level. Importantly, these effects are quantitatively more evident in SNc DA neurons. We conclude that Ih regulates the responsiveness to excitatory synaptic transmission in SNc and VTA DA neurons differentially. Finally, we present the hypothesis that Ih loss of function may be linked to PD trigger mechanisms, such as mitochondrial failure and ATP depletion, and act in concert with SNc‐specific synaptic connectivity to promote selective vulnerability.     

miR-181b as a therapeutic agent for chronic lymphocytic leukemia in the Eμ-TCL1 mouse model

The involvement of microRNAs (miRNAs) in chronic lymphocytic leukemia (CLL) pathogenesis suggests the possibility of anti-CLL therapeutic approaches based on miRNAs. Here, we used the Eμ-TCL1 transgenic mouse model, which reproduces leukemia with a similar course and distinct immunophenotype as human B-CLL, to test miR-181b as a therapeutic agent.In vitro enforced expression of miR-181b mimics induced significant apoptotic effects in human B-cell lines (RAJI, EHEB), as well as in mouse Eμ-TCL1 leukemic splenocytes. Molecular analyses revealed that miR-181b not only affected the expression of TCL1, Bcl2 and Mcl1 anti-apoptotic proteins, but also reduced the levels of Akt and phospho-Erk1/2. Notably, a siRNA anti-TCL1 could similarly down-modulate TCL1, but exhibited a reduced or absent activity in other relevant proteins, as well as a reduced effect on cell apoptosis and viability. In vivo studies demonstrated the capability of miR-181b to reduce leukemic cell expansion and to increase survival of treated mice.These data indicate that miR-181b exerts a broad range of actions, affecting proliferative, survival and apoptotic pathways, both in mice and human cells, and can potentially be used to reduce expansion of B-CLL leukemic cells.     

The role of 9-O-acetylated ganglioside D3 (CD60) and ��4��1 (CD49d) expression in predicting the survival of patients with S��zary syndrome

Background

Sézary syndrome is a rare and very aggressive leukemic variant of cutaneous T-cell lymphoma characterized by extensive skin involvement and a malignant circulating CD4⁺ T-cell clone which homes to the skin, over-expresses CD60, and lacks CD7, CD26 and CD49d. So far prognostic markers in this disease are limited to treatment with systemic steroids, age, serum lactate dehydrogenase, and a white blood cell count of 20×10⁹/L or higher: no other biological marker with prognostic value, especially related to malignant cells, has been described.

Design and Methods

We used flow activated cell sorting analysis to compare the distribution of the T-cell receptor-Vβ repertoire and several surface molecules (CD7, CD26, CD49d and CD60) within the circulating CD4⁺ T-cell population in 62 patients with Sézary syndrome, 180 with mycosis fungoides, 6 with B-cell lymphomas, and 19 with chronic eczema. We calculated the 5-year overall survival of patients with Sézary syndrome after first hospital admission using Kaplan–Meier product–limit estimates and hazard ratios from the Cox proportional hazards model.

Results

We found that both higher number of CD60⁺ and lower number of CD49d⁺ cells within circulating CD4⁺ T cells at disease presentation were significantly associated with a lower probability of survival. An exceedingly high risk of death was observed for patients with a combination of a high proportion of CD4⁺CD60⁺ cells (≥ 0.5×10⁹/L) and low proportion of CD4⁺CD49d⁺ cells (<0.5×10⁹/L) (hazard ratio = 12.303, 95% confidence interval 1.5–95.9; P<0.02). In addition, a skewed usage of T-cell receptor-Vβ subfamilies was observed in the circulating T-cell clone for 61.9% of all patients with Sézary syndrome, T-cell receptor-Vβ 2 and 5.1 subfamilies being the most frequently represented (42.8%), followed by T-cell receptor-Vβ 12 and 13.1.

Conclusions

In this study we showed that up-regulation of CD60 and down-regulation of CD49d on circulating CD4⁺ T cells are two useful markers for predicting a very poor outcome in patients with Sézary syndrome.     

Nifedipine Reduces the Colonic Motor Response to Eating in Patients with the Irritable Colon Syndrome

Patients with the irritable colon syndrome have an exaggerated and/or prolonged colonic motor response to eating. This is believed to be the cause of their postprandial complaints. Since the flux of calcium ions across cell membranes plays a major role in the contractions of the gastrointestinal smooth muscle, we investigated the effect of nifedipine, a calcium channel blocker, on the gastrocolonic response in nine patients with the irritable colon syndrome. Colonic myoelectric and contractile activity was recorded during fasting and after a 1000-cal mixed meal, either with or without nifedipine (20 mg sublingually) administration. Nifedipine reduced the postprandial increase of both spike potential activity and motility index. This effect of acute administration of the drug provides rational support to test nifedipine in clinical trials as a possible means for treating the irritable colon syndrome.     

Impaired T- and B-cell development in Tcl1-deficient mice

TCL1, the overexpression of which may result in T-cell leukemia, is normally expressed in early embryonic tissues, the ovary, and lymphoid lineage cells. Our analysis of mouse B-lineage cells indicates that Tcl1 expression is initiated in pro-B cells and persists in splenic marginal zone and follicular B cells. T-lineage Tcl1 expression begins in thymocyte progenitors, continues in CD4(+)CD8(+) thymocytes, and is extinguished in mature T cells. In Tcl1-deficient mice, we found B lymphopoiesis to be compromised at the pre-B cell stage and T-cell lymphopoiesis to be impaired at the CD4(+)CD8(+) thymocyte stage. A corresponding increase was observed in thymocyte susceptibility to anti-CD3epsilon-induced apoptosis. Reduced numbers of splenic follicular and germinal center B cells were accompanied by impaired production of immunoglobulin G1 (IgG1) and IgG2b antibodies in response to a T-dependent antigen. The marginal zone B cells and T-cell-independent antibody responses were also diminished in Tcl1(-/-) mice. This analysis indicates a significant role for Tcl1, a coactivator of Akt signaling, in normal T- and B-cell development and function.     

Atrial fibrillation ablation: is common practice far from guidelines’ world? The Italian experience from a national survey

Journal of Interventional Cardiac Electrophysiology - Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, occurring in 1–2% of the general population. Catheter ablation...