3,205 research outputs found

    Classification of human actions into dynamics based primitives with application to drawing tasks

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    We develop the study of primitives of human motion, which we refer to as movemes. The idea is to understand human motion by decomposing it into a sequence of elementary building blocks that belong to a known alphabet of dynamical systems. How can we construct an alphabet of movemes from human data? In this paper we address this issue by introducing the notion of well-posednes. Using examples from human drawing data, we show that the well-posedness notion can be applied in practice so to establish if sets of actions, viewed as signals in time, can define movemes

    A thermodynamic signature of lipid segregation in biomembranes induced by a short peptide derived from glycoprotein gp36 of feline immunodeficiency virus.

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    The interactions between proteins/peptides and lipid bilayers are fundamental in a variety of key biological processes, and among these, the membrane fusion process operated by viral glycoproteins is one of the most important, being a fundamental step of the infectious event. In the case of the feline immunodeficiency virus (FIV), a small region of the membrane proximal external region (MPER) of the glycoprotein gp36 has been demonstrated to be necessary for the infection to occur, being able to destabilize the membranes to be fused. In this study, we report a physicochemical characterization of the interaction process between an eight-residue peptide, named C8, modeled on that gp36 region and some biological membrane models (liposomes) by using calorimetric and spectroscopic measurements. CD studies have shown that the peptide conformation changes upon binding to the liposomes. Interestingly, the peptide folds from a disordered structure (in the absence of liposomes) to a more ordered structure with a low but significant helix content. Isothermal titration calorimetry (ITC) and differential scanning calorimetry (DSC) results show that C8 binds with high affinity the lipid bilayers and induces a significant perturbation/reorganization of the lipid membrane structure. The type and the extent of such membrane reorganization depend on the membrane composition. These findings provide interesting insights into the role of this short peptide fragment in the mechanism of virus-cell fusion, demonstrating its ability to induce lipid segregation in biomembranes

    Enhancement of cytosine arabinoside-induced apoptosis in human myeloblastic leukemia cells by NFkB/Rel- specific decoy oligodeoxynucleotides

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    The activity of NF-kB/Rel nuclear factors is known to inhibit apoptosis in various cell types. We investigated whether the subtraction of NF-kB/Rel activity influenced the response of 11 AML (M1, M2 and M4) patients’ cells to AraC. To this end we used a phosphorothioate double-stranded decoy oligodeoxynucleotide (ODN) carrying the NF-kB/Rel- consensus sequence. Cell incubation with this ODN, but not its mutated (scrambled) form used as a control, resulted in abating the NF-kB/Rel nuclear levels in these cells, as verified by electrophoretic mobility shift assay (EMSA) of cells’ nuclear extracts. We incubated the leukemic cells with AraC (32 or 1 mM), in either the absence or presence of the decoy or the scrambled ODN, and analyzed cell apoptosis. The spontaneous cell apoptosis detectable in the absence of AraC (,25%) was not modulated by the oligonucleotide presence in cell cultures. On the other hand, in 10 of the 11 samples tested, the decoy kB, but not the scrambled ODN significantly (P ,0.01 in a Student’s t test) enhanced cell apoptotic response to AraC. Such an effect was particularly remarkable at low AraC doses (1 mM). These findings indicate that NF-kB/Rel activity influences response to AraC in human primary myeloblastic cells, and suggests that the inhibition of NF-kB/Rel factors can improve the effect of chemotherapy in AM

    A randomized phase II study comparing sequential versus simultaneous chemo-radiotherapy in patients with unresectable locally advanced squamous cell cancer of the head and neck

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    Background: Single-modality radiotherapy is still considered standard treatment for patients with locally advanced unresectable cancer of the head and neck. As treatment outcome is poor, attempts to integrate chemotherapy into the overall management of these patients are ongoing. Patients and methods: A randomized study was undertaken to compare a sequential with a simultaneous chemoradiotherapy program. Between February 1986 and February 1991, 93 eligible patients with locally advanced unresectable cancer of the head and neck were stratified by WHO PS, T and N class and primary site and then randomized to receive either three courses of neoadjuvant chemotherapy with cisplatin (100 mg/m2 i.v. d 1) and 5-fluorouracil 1000 mg/m2/days 1-5 by continuous i.v. infusion every 3 weeks prior to definitive conventional radiotherapy of 65-70 Gy (sequential treatment), or cisplatin 100 mg/m2 on days 1, 22, 43 given simultaneously for the duration of the same conventional radiotherapy (simultaneous treatment). Results: At the end of the entire treatment 18 complete responses (47%) in the sequential-treatment arm and 18 (41%) in the simultaneous treatment arm were obtained. No statistically significant differences in the 5-yr progression-free survival, in the median time to loco-regional and distant progression and in the 5-yr overall survival were observed. Leukopenia was more frequent in the simultaneous than in the sequential arm (p = 0.03), whereas alopecia (p = 0.008) and phlebitis (p < 0.0001) were more frequent in the sequential-treatment arm. A better compliance was associated with the concomitant treatment, with 87% of the patients completing the entire radiotherapy program versus 63% of those in the sequential arm (p = 0.01). Conclusions: In the present study, the two treatment arms showed similar activity (complete response, progression-free and overall survival rates). Compliance to treatment was better in the concomitant arm. These data suggest that concomitant chemo-radiation therapy might be considered an option in unresectable locally advanced cancer of the head and neck. Phase III studies are needed in order to establish the superiority of this combination of cisplatin and radiotherapy versus radiotherapy alone

    Super selective arterial embolization to treat radiation-induced hemorrhagic gastritis: a case report and review of the literature

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    Radiation-induced hemorrhagic gastritis (RIHG) is a rare but potentially fatal event following radiotherapy for locally advanced gastric cancer; the treatment of this condition is not standardized. Only few cases of RIHG have been reported, treated with different therapeutic approaches. Here we report the case of a 79-year-old patient who underwent subtotal gastrectomy for gastric cancer, followed by adjuvant chemo-radiotherapy. Approximately 3 months after the end of the treatment, she developed recurrent diffuse bleeding originating from the entire mucosa of the gastric pouch and from a marginal ulcer. As the bleeding was refractory to several endoscopic treatments and surgery was not indicated, the patient underwent two sessions of transcatheter selective arterial embolization, with resolution of bleeding. Arterial embolization has already been reported for the treatment of hemorrhagic cystitis, developing after irradiation of the pelvis for prostate, bladder, rectum, and cervix cancer. However, to our knowledge, it has never been reported as a treatment for hemorrhagic gastritis. Based on this case, we suggest arterial embolization as an option in the management of RIHG, when standard endoscopic treatment fails

    Impact of a single point mutation on the antimicrobial and fibrillogenic properties of cryptides from human apolipoprotein B

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    Host defense peptides (HDPs) are gaining increasing interest, since they are endowed with multiple activities, are often effective on multidrug resistant bacteria and do not generally lead to the development of resistance phenotypes. Cryptic HDPs have been recently identified in human apolipoprotein B and found to be endowed with a broad-spectrum antimicrobial activity, with antibiofilm, wound healing and immunomodulatory properties, and with the ability to synergistically act in combination with conventional antibiotics, while being not toxic for eukaryotic cells. Here, a multidisciplinary approach was used, including time killing curves, differential scanning calorimetry, circular dichroism, ThT binding assays, and transmission electron microscopy analyses. The effects of a single point mutation (Pro → Ala in position 7) on the biological properties of ApoB-derived peptide r(P)ApoBLPro have been evaluated. Although the two versions of the peptide share similar antimicrobial and anti-biofilm properties, only r(P)ApoBLAla peptide was found to exert bactericidal effects. Interestingly, antimicrobial activity of both peptide versions appears to be dependent from their interaction with specific components of bacterial surfaces, such as LPS or LTA, which induce peptides to form β-sheet-rich amyloid-like structures. Altogether, obtained data indicate a correlation between ApoB-derived peptides self-assembling state and their antibacterial activity
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