S. De Santis

Alterations of the FLT3 gene in acute promyelocytic leukemia: association with diagnostic characteristics and analysis of clinical outcome in patients treated with the Italian AIDA protocol.

Alterations in the FLT3 gene, including internal tandem duplications (ITDs) and D835 mutations occur frequently in acute myelogenous leukemia. We investigated the prevalence and clinico-biological correlations of FLT3 ITDs and D835 mutations in 90 patients with acute promyelocytic leukemia (APL) receiving the AIDA protocol. Twenty patients in which both presentation and relapse material was available were analyzed sequentially. Thirty-three patients (37%) harbored the ITD, and seven (7.7%) the D835 mutation in blasts obtained at diagnosis. Presence of ITDs was strongly associated with high WBC count (P = 0.0001), M3 variant (P = 0.0004), and the short (BCR3) PML/RARα isoform (P = 0.003). There was no difference in response to induction in the two ITD+ve and ITD−ve groups, while a trend towards inferior outcome was observed for ITD+ve cases when analyzing disease-free survival (DFS) and relapse risk (RR). These differences, however, did not reach statistical significance. Sequential studies showed variable patterns in diagnostic and relapse material, ie ITD (−ve/−ve, +ve/+ve, +ve/−ve, −ve/+ve) and D835 (−ve/−ve, +ve/−ve, −ve/+ve). Our results indicate that FLT3 alterations are associated in APL with more aggressive clinical features and suggest that these lesions may not play a major role in leukemia progression.

Anisotropic anomalous diffusion assessed in the human brain by scalar invariant indices.

A new method to investigate anomalous diffusion in human brain, inspired by the stretched‐exponential model proposed by Hall and Barrick, is proposed here, together with a discussion about its potential application to cerebral white matter characterization. Aim of the work was to show the ability of anomalous diffusion indices to characterize white matter structures, whose complexity is only partially accounted by diffusion tensor imaging indices. MR signal was expressed as a stretched‐exponential only along the principal axes of diffusion; whereas, in a generic direction, it was modeled as a combination of three stretched‐exponentials. Indices to quantify the tissue anomalous diffusion and its anisotropy, independently of the experiment reference frame, were derived. Experimental results, obtained on 10 healthy subjects at 3T, show that the new parameters are highly correlated to intrinsic local geometry when compared with Hall and Barrick indices. Moreover, they offer a different contrast in white matter regions when compared with diffusion tensor imaging. Specifically, the new indices show a higher capability to discriminate among areas of the corpus callosum associated to different distribution in axonal densities, thus offering a new potential tool to detect more specific patterns of brain abnormalities than diffusion tensor imaging in the presence of neurological and psychiatric disorders. Magn Reson Med, 2010.

Allogeneic stem cell transplantation for advanced acute promyelocytic leukemia: results in patients treated in second molecular remission or with molecularly persistent disease

In all, 17 consecutive patients in hematological complete remission (HCR) of acute promyelocytic leukemia (APL) received allogeneic stem cell transplantation (SCT) from an HLA-identical sibling and were monitored by reverse transcriptase polymerase chain reaction of PML/RARα prior and after transplant. Median age was 31 years (range 3–50 years). At 10 years, the actuarial probabilities of nonrelapse mortality, relapse and disease-free survival were 32% (95% CI: 8–56%), 33% (95% CI: 6–60%) and 46% (95% CI: 22–70%). Six patients tested PCR +ve (1st HCR n=2; 2nd HCR n=3; 3rd HCR n=1) and 11 PCR −ve (2nd HCR n=11) pre-SCT. Of the six patients PCR +ve, two showed early persistence of PCR positivity and converted to sustained PCR negativity after CSA withdrawal (one died of secondary tumor in molecular remission and one is alive in relapse), while four converted to PCR −ve rapidly (one died of the underlying disease and three are in molecular remission). Of the 11 patients PCR −ve pre-SCT, six died (four of transplant-related mortality, one of relapse and one after heart transplantation) and five are alive, four in molecular remission and one is in relapse. Allogeneic SCT seems a valid option for advanced APL, particularly for the poor prognostic group of patients with pre-SCT molecularly persistent disease.

Spatio-temporal anomalous diffusion in heterogeneous media by nuclear magnetic resonance

In this paper, we describe nuclear magnetic resonance measurements of water diffusion in highly confined and heterogeneous colloidal systems using an anomalous diffusion model. For the first time, temporal and spatial fractional exponents, α and μ, introduced within the framework of continuous time random walk, are simultaneously measured by pulsed gradient spin-echo NMR technique in samples of micro-beads dispersed in aqueous solution. In order to mimic media with low and high level of disorder, mono-dispersed and poly-dispersed samples are used. We find that the exponent α depends on the disorder degree of the system. Conversely, the exponent μ depends on both bead sizes and magnetic susceptibility differences within samples. The new procedure proposed here may be a useful tool to probe porous materials and microstructural features of biological tissue.

In vitro and in vivo MR evaluation of internal gradient to assess trabecular bone density

Here we propose a new magnetic resonance (MR) strategy based on the evaluation of internal gradient (G(i)) to assess the trabecular bone (TB) density in spongy bone. Spongy bone is a porous system characterized by a solid trabecular network immersed in bone marrow and characterized by a different relative percentage of water and fats. Using a 9.4 T MR micro-imaging system, we first evaluated the relative water and fat G(i) as extracted from the Spin-Echo decay function in vitro of femoral head samples from calves. Indeed, the differential effects of fat and water diffusion result in different types of G(i) behavior. Using a clinical MR 3T scanner, we then investigated in vivo the calcanei of individuals characterized by different known TB densities. We demonstrate, on these samples, that water is more prevalent in the boundary zone, while fats are rearranged primarily in the central zone of each pore. In vitro experiments showed that water G(i) magnitude from the samples was directly proportional to their TB density. Similar behavior was also observed in the clinical measures. Conversely, fat G(i) did not provide any information on spongy-bone density. Our results suggest that water G(i) may be a reliable marker to assess the status of spongy bone.

Cerebral Dura Mater and Cephalalgia: Relationships Between Mast Cells and Catecholaminergic Nerve Fibers in the Rat

The aim of the present study was to examine whether mast cells have the same variations as the related catecholaminergic nerve fibers. Chemical sympathectomy or surgical removal of right superior cervical ganglion induced a rapid decrease of fluorescence in both nerve fibers and mast cells, as confirmed by quantitative analysis (nerve fibers 19±1.1 vs 1.3±0.6; mast cell 10.8±1.9 vs 2.1±0.3). The results of quantitative analysis after nerve fiber stimulation (electrical), however, showed an increase of the fluorescence in both the nerve fibers and the mast cells (nerve fibers 43.4 ±2.4; mast cells 18.6 ±1.6). Moreover, we found that the basal zone is more innervated (regarding catecholaminergic nerve fibers) than the apical one, and that the fluorescence level decreases passing from the vasal zone to the perivasal and intervasal zones. Further studies are needed in order to clarify the role of fluorescent nerve fibers and mast cells of cerebral dura mater in cephalalgia.

Diabetic rats treated by low molecular weight heparin OP 2123/parnaparin: Morphological changes in the kidney and heart

AIM Early morphological alterations in the rat kidney and heart due to experimentally induced diabetes are described in order to evaluate the possible therapeutic role of low molecular weight heparin (LMWH; OP 2123/parnaparin). METHODS Our findings concern the alterations observed in the rat kidney and heart because these are the organs (together with the retina) mainly involved in the early morphological angiopathic modifications associated with diabetic damage of organs and tissues. In diabetic animals treated with LMWH, the Periodic Acid-Schiff (PAS) reaction showed a slight decrease when compared with the diabetic control group. Photographs were submitted to the quantitative analysis of images using a Quantimet 500 Image Analyzer (Leica) equipped with specific software. The following parameters were measured: (1) total area occupied by alkaline phosphatase (AP)-positive capillaries; (2) number and diameter of AP-positive capillaries; (3) distribution and total area occupied by PAS-positive structures (related to the intensity of the reaction resulting from the different amount of mucopolysaccharides). RESULTS LMWH treatment is efficient in preventing these modifications, above all in the kidney. The histological study of the heart and kidney shows no significant, relevant alterations. However, the histological study of the mucopolysaccharides in diabetic animals highlighted a tendency for the heart to accumulate these substances. LMWH treatment only modestly reduced this accumulation. CONCLUSIONS Previous evidence demonstrating a beneficial effect of therapy based on heparan sulphate proteoglycans and/or other heparin-like substances in insulin-dependent diabetes mellitus seems to be confirmed by our experimental results in different organs of adult rats. In fact, parnaparin treatment is effective (in our experience) for ameliorating the morphological pattern observed early in some diabetic tissues of rats and, above all, in the kidney.

Interleukin 1β and GABA-transaminase activity in rat thymus

Abstract The occurrence and distribution of 4-aminobutyrate:2 oxoglutarate transaminase (GABA-t) activity were examined in the rat thymus of normal and immunostimulated rats using biochemical and histoenzymatical methods. Specific GABA-t reactivity was confined primarily to the arteries and, to a lesser extent, to the veins. Only a few activities could be observed in association with the subcapsular and medullar part of the parenchyma and nerve fibers. GABA-t was considered a linking enzyme between the immune and the nervous system and it was studied with the aim of analyzing the relationships between these two systems. Our findings indicate that the GABA-t activity in the thymus is specifically located in the wall of the blood vessels. Moreover, our results demonstrate the presence of a GABA-t activity in the peripheral blood vessels. Treatment with interleukin 1β induces an increase of protein content of the amounts of GABA-t biochemically assayed and of the levels of histoenzymatically stained GABA-t. Furthermore, staining of the different structures of the thymus in treated or untreated rats shows that the significant modifications concern the parenchyma, the structures resembling nerve fibers and finally, the whole thymus. On the contrary, the highest activity of the GABA-t is located in the walls of arteries, veins and lymphatic vessels.

Evaluation of the beam-coupling impedances of the DAΦNE cavity: numerical and analytical results

Abstract Waveguide dampers are going to be widely used in accelerator RF cavities to reduce the beam-coupling impedances at the frequency of the higher order modes, in order to avoid multi-bunch instabilities. The numerical evaluation of the beam-coupling impedances in cavities equipped with waveguide dampers leads to the solution of a 3D field problem, that requires a vast amount of computing time on powerful computers. In this paper we present a simple analytical method, based on the well-known Kirchhoff approximation, that permits an evaluation of the coupling between the cavity and the waveguide modes, thus yielding a first estimate of the Q -factors of the damped modes. We also discuss the evaluation of the damping effect in the case of the DAΦNE RF cavity through the post-processing of the data from a 3D code. The results of the two approaches are compared, and checked against experimental results and other numerical simulations.

Molecular Diagnosis and Monitoring of Acute Promyelocytic Leukemia: Updated Results of the Italian Gimema Group

Long before the advent of all-trans retinoic acid (ATRA) acute promyelocytic leukemia was recognised as a distinct subset of acute myeloid leukemia (AML) with peculiar clinico-biological features and treatment requirements. These include the frequent association at diagnosis of a life threatening hemorrhagic syndrome, the presence in leukemic blasts of a unique t(15;17) translocation and a striking sensitivity to anthracyclines even if used as single agents [1]. Two paramount discoveries, i.e. the capability of APL blasts to undergo differentiation in vitro and in vivo following treatment with vitamin A derivatives such as all-trans retinoic acid (ATRA), and the cloning of genes involved in the t(15;17), paved the way in the early 90’s to modern treatment strategies, refined diagnosis and disease monitoring at the molecular level [2-6]. Besides providing a rapid detection of the PML/RARμ fusion underlying the t(15;17), the use of reversetranscriptase polymerase chain reaction (RT-PCR) allow sensitive monitoring of minimal residual disease (MRD), therefore representing a powerful toll to better assess response to treatment in these patients. Using conventional RT-PCR assays with sensitivity levels of 103-104, several retrospective studies showed that persistence or reappearance of PCR-detectable MRD during hematologic remission correlate with subsequent relapse, whereas patients in long-term survival have no detectable PML/RARa transcripts [6].