Genome-wide CRISPR/Cas9 library screening identified ATM signaling network genes as critical drivers for resistance to ATR inhibition in soft-tissue sarcomas: synthetic lethality and therapeutic implications.

Soft-tissue sarcoma (STS) are a heterogeneous group of rare tumors with different biological behavior that are fatal in more than 40% of cases, due to their metastatic evolution and inadequate treatment options. ATR inhibition already showed an activity, even if modest, in broad pre-clinical models of STS. By using genome-wide CRISPR/Cas9 library screening, we identified ATM signaling network genes as critical drivers for resistance to the specific ATR inhibitor AZD6738. The role of such genes in resistance to AZD6738 was confirmed by using CRISPR/Cas9 knockout models. More strikingly, the ATM inhibitor AZD0156 works synergistically with AZD6738 in vitro and abolishes STS growth in vivo in our models of most frequent histotypes (such as dedifferentiated liposarcoma, leiomyosarcoma, and undifferentiated pleomorphic sarcoma among others). Moreover, the combination of AZD6738 and AZD0156 induced significantly higher levels of DNA damage than either drug used as single agent alone. In summary, our results demonstrate that targeting ATM is an effective approach to overcome resistance to ATR inhibition in different STS subtypes, including the most frequent histologies.

Surgical Treatment of Posttraumatic Radioulnar Synostosis.

Radioulnar synostosis is a rare complication of forearm fractures. The formation of a bony bridge induces functional disability due to limitation of the pronosupination. Although the etiology of posttraumatic synostosis is unknown, it seems that the incidence is higher in patients who have suffered a concomitant neurological or burn trauma, and extensive soft tissue injury, mainly due to high-energy impact. Surgical treatment, such as reinsertion of distal biceps tendon into the radius, seems to be another possible factor. The aim of the surgical treatment is to remove the bony bridge and restore complete range of movement (ROM), thus preventing recurrence. Literature does not indicate a preferred type of surgical procedure for the aforementioned complication; however, it has been shown that surgical interposition of inert material reduces the formation rate of recurrent bony bridge. We describe a surgical technique in two cases in which the radius and ulna were wrapped with allogenic, cadaver fascia lata graft to prevent bony bridge formation. The data from 2 years of follow-up are reported, indicating full restoration of ROM and no recurrence of synostosis.

Italian Society for Rheumatology recommendations for the management of hand osteoarthritis.

Hand osteoarthritis (OA) is a common and potentially disabling disease, with different features from hip and knee OA so that a specific therapeutic approach is required. Evidence based recommendations for the management of hand OA were developed by the European League Against Rheumatism (EULAR) in 2006. The Italian Society for Rheumatology (SIR) aimed to update, adapt to national contest and disseminate the EULAR recommendations for the management of hand OA. The multidisciplinary group of experts included specialists involved in the management of patients with hand OA. In order to maintain consistency with EULAR recommendations, a similar methodology was utilized by the Italian group. The original propositions were reformulated in terms of a search query and for every recommendation a systematic search was conducted updating EULAR recommendations' review. The propositions were translated in Italian and reformulated basing on collected evidences and expert opinion. The strength of recommendation was measured for each proposition with the EULAR ordinal and visual analogue scales. The original 11 propositions of EULAR recommendations were translated and adapted to Italian context. Further evidences were collected about non-pharmacological therapies, local treatments, intra-articular injection with SYSADOA and corticosteroids, and surgery. The SIR has developed updated recommendations for the management of hand OA adapted to the Italian healthcare system. Their implementation in clinical practice is expected to improve the management of patients with hand OA.

Reconstruction of the thumb with a modified wrap-around flap in a patient suffering from ß-thalassemia minor.

Thalassemia is a congenital hemolytic disorder caused by a partial or complete deficiency of α- or ß-globin chain synthesis. It has been seen that thalassemic patients exhibit an increased frequency of thrombotic events. The article presents the first case of thumb reconstruction with a modified wrap-around flap in a patient suffering from ß-thalassemia minor.

Proteomics analysis for the identification of three species of Thunnus.

The genus Thunnus comprises many species, some of higher quality and commercial value for their excellent organoleptic features, while others of lower quality and value. Consequently, these species are subjected to frequent fraudulent substitution. Increasing trade in fillet and minced fish makes the identification of external anatomical and morphological features of fish impossible. Proteomics was used for the identification of three Thunnus species. Muscle extracts were evaluated by both mono- and two-dimensional electrophoresis and mass spectrometric techniques. Preliminary results demonstrate that the tested species displays a high degree of polymorphism, making possible an accurate identification.

Efficiency of Hyaloglide in the prevention of the recurrence of adhesions after tenolysis of flexor tendons in zone II: a randomized, controlled, multicentre clinical trial.

Hyaloglide is a hyaluronan-based gel based on a novel auto-crosslinked technology designed to reduce postsurgical adhesions. Its efficacy was assessed in a multicentred randomized controlled trial comparing the results of flexor tenolysis in zone 2 following failed flexor tendon repairs. In the control group a standard release was performed. In the treated group, Hyaloglide was applied into the flexor sheath and around the site of tenolysis. Forty-five patients, 19 controls and 26 treated with Hyaloglide, were enrolled in 13 centres. All the patients were evaluated at 30, 60, 90 and 180 days after surgery by testing Total Active Motion, Quick-DASH questionnaire and number of working days lost after surgery. Patients in the Hyaloglide group had a statistically better recovery of finger motion at all time intervals and returned earlier to work and daily activities. The use of Hyaloglide did not appear to increase the complication rate.

Skeletal reconstruction with a free vascularized fibula graft associated to bone allograft after resection of malignant bone tumor of limbs.

Over the last twenty years, progress in diagnosis and in adjuvant therapy in the field of malignant bone tumor treatment has allowed for development of limb-saving surgical techniques after oncological excision. In this context, the use of vascularized fibula for transplantation represents an important instrument in the reconstruction of bone, either with or without allografts.Moreover, in pediatric cases, the vascularized transplant of the proximal fibula with its open physis allows for an adequate reconstruction of the bone loss and the possibility of conserving the growth potential of the segment. The purpose of this article is to illustrate the various reconstructive possibilities that the use of the combined graft technique (VFT plus allograft) offers in the treatment of large-scale bone loss. In our department from 1988 to 2000, 142 vascularized fibula transplants were performed in oncological cases. Surgical reconstruction was carried out on the tibia in 70 cases, on the femur in 40, on the humerus in 26 and on the radius in 6. Combined graft intercalary reconstructions were 92. In 22 pediatric cases the fibula was transplanted, including the proximal growing epiphysis in the graft; in two of these cases massive allograft was associated to the VFG. Because of its biological properties, the grafted vascularized fibula allowed for fast bone fusion at the level of the osteotomy. It has also demonstrated a tendency of progressive hypertrophy and osteointegration with the allograft, when used. In 22 pediatric cases, the fibula graft with the proximal epiphysis maintained its ability to grow. Unsuccessful outcomes caused by vascular, mechanical, or septic failure were equal to 8.2 %. The fibula graft in the reconstruction of bone loss secondary to oncological excision is a trustworthy and versatile technique.

On the convergence of the conformational coordinates basis set obtained by the essential dynamics analysis of proteins' molecular dynamics simulations.

In this article we present a quantitative evaluation of the convergence of the conformational coordinates of proteins, obtained by the Essential Dynamics method. Using a detailed analysis of long molecular dynamics trajectories in combination with a statistical assessment of the significance of the measured convergence, we obtained that simulations of a few hundreds of picoseconds are in general sufficient to provide a stable and statistically reliable definition of the essential and near constraints subspaces, at least within the nanoseconds time range. Proteins 1999;36:419-424.

Effects of core-packing on the structure, function, and mechanics of a four-helix-bundle protein ROP.

The effects of core-packing on the structure, function and mechanics of the RNA-binding 4-helix-bundle Rop have been studied by molecular dynamics simulations. The structural, dynamical and geometrical properties of the Rop homodimer, (formed by the antiparallel juxtaposition of two helix-turn-helix motifs), have been compared with those of three protein variants described by Munson et al. (Protein Sci, 5:1584-1593, 1996), where the core of the native protein has been systematically repacked using a two-amino acid alphabet: Ala(2)Leu(2)-8, Ala(2)Leu(2)-8-rev, and Leu(2)Ala(2)-8. The results showed that it was possible to readily distinguish the inactive protein Leu(2)Ala(2)-8 from the other functionally active systems based on tertiary and quaternary structure criteria. Structural properties such as native secondary structure content did not correlate with biological activity. Biological activity was related in part to the relative arrangement of the residues within the binding site. But, more global aspects, related to the overall topology of the helical bundle, accounted for the small functional differences between Ala(2)Leu(2)-8 and Ala(2)Leu(2)-8-rev. Mechanically, the 4-helix-bundle absorbed core mutations by altering the local structure at the sequence termini and in the turns that join the two helices of each monomer, and by changing the overall orientation and separation of the extremely rigid helices. Proteins 1999;36:436-446.

A kinetic model for the internal motions of proteins: diffusion between multiple harmonic wells.

The dynamics of collective protein motions derived from Molecular Dynamics simulations have been studied for two small model proteins: initiation factor I and the B1 domain of Protein G. First, we compared the structural fluctuations, obtained by local harmonic approximations in different energy minima, with the ones revealed by large scale molecular dynamics (MD) simulations. It was found that a limited set of harmonic wells can be used to approximate the configurational fluctuations of these proteins, although any single harmonic approximation cannot properly describe their dynamics. Subsequently, the kinetics of the main (essential) collective protein motions were characterized. A dual-diffusion behavior was observed in which a fast type of diffusion switches to a much slower type in a typical time of about 1-3 ps. From these results, the large backbone conformational fluctuations of a protein may be considered as "hopping" between multiple harmonic wells on a basically flat free energy surface.

Mechanics and dynamics of B1 domain of protein G: role of packing and surface hydrophobic residues.

The structural organization of the B1 domain of streptococcal protein G (PGA) has been probed using molecular dynamics simulations, with a particular emphasis on the role of the solvent exposed Ile6 residue. In addition to the native protein (WT-PGA), three single-mutants (I6G-PGA, I6F-PGA, and I6T-PGA), one double-mutant (I6T,T53G-PGA), and three isolated peptide fragments (corresponding to the helix and the two beta-hairpins) were studied in the presence of explicit water molecules. Comparative analysis of the various systems showed that the level of perturbation was directly related to the hydrophobicity and the size of the side chain of residue 6, the internal rigidity of the proteins decreasing in the order I6T-PGA > I6G-PGA > WT-PGA > I6F-PGA. The results emphasized the importance of residue 6 in controlling both the integrity of the sheet's surface and the orientation of the helix in relation to the sheet by modulation of surface/core interactions. The effects of mutations were delocalized across the structure, and glycine residues, in particular, absorbed most of the introduced strain. A qualitative structural decomposition of the native fold into elementary building-blocks was achieved using principal component analysis and mechanical response matrices. Within this framework, internal motions of the protein were described as coordinated articulations of these structural units, mutations affecting mostly the amplitude of the motions rather than the structure/location of the building-blocks. Analysis of the isolated peptidic fragments suggested that packing did not play a determinant role in defining the elementary building-blocks, but that chain topology was mostly responsible.

Intraepiphyseal resection of the proximal tibia and its impact on lower limb growth.

From 1989 through 1996, 10 children affected by high grade bone tumors of the proximal tibia underwent an intraepiphyseal intercalary resection. The residual epiphyseal bone segment measured less than 2 cm in thickness in all cases and reconstruction always was performed using the combination of a vascularized fibular autograft and a massive bone allograft. The proximal epiphyseal osteosynthesis was fixed by small fragment screws. The aim of this study was to report the growth pattern of the residual proximal tibial epiphysis and to evaluate any possible lower limb discrepancy and/or deformity after the end of skeletal maturity. At current followup six patients were available for the final evaluation. Radiographic documentation included computed tomography scan of both knees before surgery, a panoramic radiographic view and a computed tomography scan of both lower limbs after the end of skeletal growth. The length of both femurs and tibias, the size of the tibial plateau and of the opposite distal femur, and any possible deformity of femur or tibia were measured and compared with the preoperative data. No patient had a limb length discrepancy greater than 3.5 cm. In all cases the ipsilateral femur had a valgus deformity of the hip develop. In two patients this deformity was associated with an elongation of the femur, partially compensating for the shortening of the tibia. The tibial plateau close to reconstruction grew less than the contralateral one (range 2%-8%) but maintained its normal relationship with the distal femur. None of these patients reported any restriction in recreational activities. They could walk, run, and jump. Their functional result according the International Society of Limb Salvage functional grading system was satisfactory in all cases.

Thrombin receptor-activating peptides (TRAPs): investigation of bioactive conformations via structure-activity, spectroscopic, and computational studies.

The thrombin receptor (PAR-1) is an unusual transmembrane G-protein coupled receptor in that it is activated by serine protease cleavage of its extracellular N-terminus to expose an agonist peptide ligand, which is tethered to the receptor itself. Synthetic peptides containing the agonist motif, such as SFLLRN for human PAR-1, are capable of causing full receptor activation. We have probed the possible bioactive conformations of thrombin receptor-activating peptides (TRAPs) by systematic introduction of certain conformational perturbations, involving alpha-methyl, ester psi(COO), and reduced-amide psi(CH2N) scans, into the minimum-essential agonist sequence (SFLLR) to probe the importance of the backbone conformation and amide NH hydrogen bonding. We performed extensive conformational searches of representative pentapeptides to derive families of putative bioactive structures. In addition, we employed 1H NMR and circular dichroism (CD) to characterize the conformational disposition of certain pentapeptide analogues experimentally. Activation of platelet aggregation by our pentapeptide analogues afforded a structure-function correlation for PAR-1 agonist activity. This correlation was assisted by PAR-1 receptor binding data, which gauged the affinity of peptide ligands for the thrombin receptor independent of a functional cellular response derived from receptor activation (i.e. a pure molecular recognition event). Series of alanine-, proline-, and N-methyl-scan peptides were also evaluated for comparison. Along with the known structural features for PAR-1 agonist peptides, our work adds to the understanding of peptide topography relative to platelet functional activity and PAR-1 binding. The absolute requirement of a positively charged N-terminus for strong agonist activity was contradicted by the N-terminal hydroxyl peptide psi(HO)S-FLLR-NH2. The amide nitrogen between residues 1 and 2 was found to be a determinant of receptor recognition and the carbonyl groups along the backbone may be involved in hydrogen bonding with the receptor. Position 3 (P3) of TRAP-5 is known to tolerate a wide variety of side chains, but we also found that the amide nitrogen at this position can be substituted by an oxygen, as in SF-psi(COO)-LLR-NH2, without diminishing activity. However, this peptide bond is sensitive to conformational changes in that SFPLR-NH2 was active, whereas SF-NMeL-LR-NH2 was not. Additionally, we found that position 3 does not tolerate rigid spacers, such as 3-aminocyclohexane-1-carboxylic acid and 2-aminocycloalkane-1-carboxylic acid, as analogues 1A, 1B, 2A, 2B, 3, 4, 5A and 5B lack agonist activity. On the basis of our results, we suggest that an extended structure of the agonist peptide is principally responsible for receptor recognition (i.e. binding) and that hydrophobic contact may occur between the side chains of the second (Phe) and fourth (Leu) residues (i.e. P2-P4 interaction).

Free vascularized growth-plate transfer after bone tumor resection in children.

Limb-salvage surgery is the standard care for most malignant tumors affecting the extremities, and a vascularized fibula transfer is probably the most popular microsurgical option to reconstruct long-bone defects. Skeletal reconstruction after bone-tumor resection involving the metepiphysis of a growing child can be successfully achieved with a vascularized fibula graft incorporating the proximal physis and active growth plate. Such a procedure has been utilized in 12 children under the age of 10 years who had malignant bone tumors located in the upper limb (3 in the distal radius, 9 in the proximal humerus). The follow-up ranged between 4 years and 3 months. Ten grafts were supplied by the anterior tibial artery, and two by the peroneal artery. The average growth rate of the grafts based on the former artery has been more than 1 cm per year, ranging between 0.75 and 1.33 cm. The authors describe a modified operative technique and discuss the clinical results of the procedure which offers a satisfactory skeletal reconstruction and prevents future limb-size discrepancy.

Reinnervated free gracilis muscle transplantation in the treatment of Volkmann's syndrome of the forearm.

Between 1989 and 1994 free gracilis muscle reinnervation was used to treat three patients severely affected with Volkmann's syndrome of the forearm. All three patients were males and they had supracondyloid fracture of the humerus, treated nonsurgically an average of 7.6 years previously. Mean age at the time of surgery was 19.3 years. The flap was transplanted in flexor function of the fingers in two of the patients, in extensor function of the wrist in one. Electromyography and successive clinical monitoring revealed an increase in contractile strength up to one year after surgery. In the first two cases final hold strength exceeded by more than 50% that of the contralateral limb, in the third case excursion of the wrist which could not be quantified, but which was useful for elementary activities was recovered. When myotendinous units for transplantation are not available, free gracilis muscle reinnervation constitutes a valid surgical solution in cases of severe Volkmann's syndrome of the forearm.

Photoaffinity labeling of methyl farnesoate epoxidase in cockroach corpora allata.

The last enzyme in the biosynthetic pathway to juvenile hormone III in the corpora allata of hemimetabolous insects is methyl farnesoate epoxidase, a cytochrome P450 monooxygenase. Assays with intact glands incubated in vitro and with gland homogenates have identified a series of 1,5-disubstituted imidazoles as potent inhibitors of the enzyme. We have designed, synthesized and tested two imidazoles, diazirine-Ice T and benzophenone-Ice T, in which a radiolabeled and photoactivatable diazirine or benzophenone group was introduced to label the hydrophobic substrate binding site of the enzyme. Our results show that these bifunctional compounds inhibit JH III synthesis by intact glands as well as methyl farnesoate epoxidation by gland homogenates. Moreover both compounds selectively label a protein of ca. 55 kDa in corpora allata of the cockroach, Diploptera punctata. These photoaffinity labels, which use an imidazole to coordinate to the heme iron and a photoreactive group to modify the hydrophobic substrate binding pocket, are specific and effective probes for the molecular analysis of methyl farnesoate epoxidase.