Inhibition of C5aR1 as a promising approach to treat taxane-induced neuropathy.

Chemotherapy-induced peripheral neuropathy (CIPN) is a common side effect of several antitumor agents resulting in progressive and often irreversible damage of peripheral nerves. In addition to their known anticancer effects, taxanes, including paclitaxel, can also induce peripheral neuropathy by activating microglia and astrocytes, which release pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin 1-beta (IL-1ß), and chemokine (C-C motif) ligand 2 (CCL-2). All these events contribute to the maintenance of neuropathic or inflammatory response. Complement component 5a (C5a)/C5a receptor 1 (C5aR1) signaling was very recently shown to play a crucial role in paclitaxel-induced peripheral neuropathy. Our recent findings highlighted that taxanes have the previously unreported property of binding and activating C5aR1, and that C5aR1 inhibition by DF3966A is effective in preventing paclitaxel-induced peripheral neuropathy (PIPN) in animal models. Here, we investigated if C5aR1 inhibition maintains efficacy in reducing PIPN in a therapeutic setting. Furthermore, we characterized the role of C5aR1 activation by paclitaxel and the CIPN-associated activation of nod-like receptor (NLR) family pyrin domain containing 3 (NLRP3) inflammasome. Our results clearly show that administration of the C5aR1 inhibitor strongly reduced cold and mechanical allodynia in mice when given both during the onset of PIPN and when neuropathy is well established. C5aR1 activation by paclitaxel was found to be a key event in the induction of inflammatory factors in spinal cord, such as TNF-α, ionized calcium-binding adapter molecule 1 (Iba-1), and glial fibrillary acidic protein (GFAP). In addition, C5aR1 inhibition significantly mitigated paclitaxel-induced inflammation and inflammasome activation by reducing IL-1ß and NLRP3 expression at both sciatic and dorsal root ganglia level, confirming the involvement of inflammasome in PIPN. Moreover, paclitaxel-induced upregulation of C5aR1 was significantly reduced by DF3966A treatment in central nervous system. Lastly, the antinociceptive effect of C5aR1 inhibition was confirmed in an in vitro model of sensory neurons in which we focused on receptor channels usually activated upon neuropathy. In conclusion, C5aR1 inhibition is proposed as a therapeutic option with the potential to exert long-term protective effect on PIPN-associated neuropathic pain and inflammation.

Characteristics of 1573 healthcare workers who underwent nasopharyngeal swab testing for SARS-CoV-2 in Milan, Lombardy, Italy.

OBJECTIVES: The management of healthcare workers (HCWs) exposed to confirmed cases of coronavirus disease 2019 (COVID-19) is still a matter of debate. We aimed to assess in this group the attack rate of asymptomatic carriers and the symptoms most frequently associated with infection. METHODS: Occupational and clinical characteristics of HCWs who underwent nasopharyngeal swab testing for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a university hospital from 24 February 2020 to 31 March 2020 were collected. For those who tested positive and for those who tested positive but who were asymptomatic, we checked the laboratory and clinical data as of 22 May to calculate the time necessary for HCWs to then test negative and to verify whether symptoms developed thereafter. Frequencies of positive tests were compared according to selected variables using multivariable logistic regression models. RESULTS: There were 139 positive tests (8.8%) among 1573 HCWs (95% confidence interval, 7.5-10.3), with a marked difference between symptomatic (122/503, 24.2%) and asymptomatic (17/1070, 1.6%) workers (p < 0.001). Physicians were the group with the highest frequency of positive tests (61/582, 10.5%), whereas clerical workers and technicians had the lowest frequency (5/137, 3.6%). The likelihood of testing positive for COVID-19 increased with the number of reported symptoms; the strongest predictors of test positivity were taste and smell alterations (odds ratio = 76.9) and fever (odds ratio = 9.12). The median time from first positive test to a negative test was 27 days (95% confidence interval, 24-30). CONCLUSIONS: HCWs can be infected with SARS-CoV-2 without displaying any symptoms. Among symptomatic HCWs, the key symptoms to guide diagnosis are taste and smell alterations and fever. A median of almost 4 weeks is necessary before nasopharyngeal swab test results are negative.

Comprehensive genomic analysis of the dromedary T cell receptor gamma (TRG) locus and identification of a functional TRGC5 cassette.

The emergent availability in public databases of more complete genome assemblies allows us to improve genomic data obtained by classical molecular cloning. The main goal of this study was to refine the genomic map of the dromedary TRG locus by integrating our previous genomic data with the analysis of recent genomic assemblies. We identified an additional TRGC cassette, defined as a V-J-C recombination unit, located at the 5' of the locus and made up of five TRGV genes followed by three TRGJ genes and one TRGC gene. Hence, the complete dromedary TRG locus spans about 105 Kb and consists of three in tandem TRGC cassettes delimited by AMPH and STARD3NL genes at the 5' and 3' end, respectively. An expression assay carried out on peripheral blood showed the functional competency for the dromedary TRGC5 cassette and confirmed the presence of the somatic hypermutation mechanism able to enlarge the repertoire diversity of the dromedary γδ T cells.

YAP/TAZ mechano-transduction as the underlying mechanism of neuronal differentiation induced by reduced graphene oxide.

AIM: The aim of this work is the dissection of the molecular pathways underlying the differentiation effect of reduced graphene oxide (GO) materials in the absence of differentiation agents. MATERIALS & METHODS: Reduced GO is obtained either by drop casting method and heat-treated or biological reduction by the interaction between GO and wtPrxI. Cells were grown on both materials and the differentiation process studied by immunological and morphological detection. RESULTS & CONCLUSION: The results obtained indicate that both reduction methods of GO can determine the modulation of pathway involved in mechano-transduction and differentiation, by affecting YAP/TAZ localization outside the nuclei and increasing neuronal differentiation markers. This suggests that the mechano-transduction pathways are responsible for the differentiation process.

PPARs in Neurodegenerative and Neuroinflammatory Pathways.

BACKGROUND: PPARs are lipid sensors activated by dietary lipids or their metabolites, mainly fatty acids and eicosanoids, that play critical roles in CNS biology, since brain has a very high lipid content and has the higher energetic metabolism in the body. METHODS: In neurodegenerative diseases in addition to metabolic impairment, also neuroinflammation is observed and PPARs are also closely linked to inflammatory processes. Several studies have revealed a complicated relationship between the innate immune response and tissue metabolism. RESULTS: In the brain, during pathological conditions, an alteration in metabolic status occurs, particularly involving glucose utilization and production, a condition which is generally related to metabolic changes. CONCLUSION: Taking into account the high expression of PPARs in the brain, this review will focus on the role of these transcription factors in CNS diseases.

Magnetic propulsion and ultrasound tracking of endovascular devices.

In this paper a robotic means of magnetic navigation of an endovascular device a few millimeters in diameter is presented. The technique, based on traditional computer-assisted surgery adapted to intravascular medical procedures, includes a manipulator for magnetic dragging interfaced with an ultrasound system for tracking the endovascular device. The main factors affecting device propulsion are theoretically analyzed, including magnetic forces, fluidic forces, and friction forces between the endovascular device and the vessel. A dedicated set-up for measuring locomotion, and for navigation with and against the flow, has been developed and preliminary tests have been performed to derive the best configuration for controlled magnetic dragging in the vascular system. Experimental outcomes are consistent with a simple analytical model that analyzes dragging of the magnetic capsule in a tube. By means of this model, different working conditions can be considered to select the appropriate conditions, for example flow rate, coefficient of friction, or magnetic properties.

A one-degree-of-freedom spherical mechanism for human knee joint modelling.

In-depth comprehension of human knee kinematics is necessary in prosthesis and orthosis design and in surgical planning but requires complex mathematical models. Models based on one-degree-of-freedom equivalent mechanisms have replicated well the passive relative motion between the femur and tibia, i.e. the knee joint motion in virtually unloaded conditions. In these mechanisms, fibres within the anterior and posterior cruciate and medial collateral ligaments were taken as isometric and anatomical articulating surfaces as rigid. A new one-degree-of-freedom mechanism is analysed in the present study, which includes isometric fibres within the two cruciates and a spherical pair at the pivot point of the nearly spherical motion as measured for this joint. Bounded optimization was applied to the mechanism to refine parameter first estimates from experimental measurements on four lower-limb specimens and to best-fit the experimental motion of these knees. Relevant results from computer simulations were compared with those from one previous equivalent mechanism, which proved to be very accurate in a former investigation. The spherical mechanism represented knee motion with good accuracy, despite its simple structure. With respect to the previous more complex mechanism, the less satisfactory results in terms of replication of natural motion were counterbalanced by a reduction of computational costs, by an improvement in numerical stability of the mathematical model, and by a reduction of the overall mechanical complexity of the mechanism. These advantages can make the new mechanism preferable to the previous ones in certain applications, such as the design of prostheses, orthoses, and exoskeletons, and musculoskeletal modelling of the lower limb.

Determination of the design specifications of a powered humeral rotator for a myoelectric prosthesis.

The University of Bologna and the INAIL Prosthesis Centre are collaborating to design new high-functionality prostheses for upper-limb amputees, with a high-level amputation, who are currently rehabilitated by inadequate commercial solutions. This study deals with the development of a new powered humeral rotator that should integrate the prosthesis previously developed by the research group, which is already provided with a terminal device, a wrist rotator, an elbow joint, and a prototype of shoulder articulation composed of two powered revolute joints. This paper focuses on the design methodology that was followed to retrieve the design input data necessary for the development of the humeral rotator. The methodology is mainly based on kinematic and kinetostatic analyses of multibody models of upper-limb prostheses. The kinematic simulations are used to define the ability of the arm models (that have less than the six degrees of freedom required for generically positioning and orienting the terminal device) satisfactorily to perform important activities of daily living, i.e. with an acceptable accuracy. Kinetostatic analyses are then performed to determine the loads acting on the humeral rotator when performing the mentioned activities, thus making it possible to define fundamental design guidelines and technical specifications.

PDE10A and PDE10A-dependent cAMP catabolism are dysregulated oppositely in striatum and nucleus accumbens after lesion of midbrain dopamine neurons in rat: a key step in parkinsonism physiopathology.

Loss of dopamine neurons in experimental parkinsonism results in altered cyclic nucleotide cAMP and cGMP levels throughout the basal ganglia. Our objective was to examine whether expression of phosphodiesterase 10A (PDE10A), an isozyme presenting a unique distribution in basal ganglia, is altered after unilateral injection of 6-hydroxydopamine in the medial forebrain bundle, eliminating all midbrain dopaminergic neurons, such that cyclic nucleotide catabolism and steady state could be affected. Our study demonstrates that PDE10A mRNA levels were decreased in striatal neurons 10 weeks after 6-hydroxydopamine midbrain lesion. Such changes occurred in the striatum ipsilateral to lesion and were paralleled by decreased PDE10A protein levels and activity in striatal neurons and in striato-pallidal and striato-nigral projections. However, PDE10A protein and activity were increased while PDE10A mRNA was unchanged in the nucleus accumbens ipsilateral to the 6-hydroxydopamine midbrain lesion. Accordingly, cAMP levels were down-regulated in the nucleus accumbens, and up-regulated in the striatum ipsilateral to the lesion, but they were not significantly changed in substantia nigra and globus pallidus. Unlike cAMP, cGMP levels were decreased in all dopamine-deafferented regions. The opposite variations of cAMP steady state in striatum and nucleus accumbens are concordant and likely dependent, at least in part, on the down-regulation of PDE10A expression and activity in the former and its up-regulation in the latter. On the other hand, the down-regulation of cGMP steady state in the striato-nigral and striato-pallidal complex is not consistent with and is likely independent from the concomitant down-regulation of PDE10A. Therefore, dopamine loss inversely regulates PDE10A gene expression in the striatum and PDE10A post-transcription in the nucleus accumbens, therein differentially modulating PDE10A-dependent cAMP catabolism.

Articular surface approximation in equivalent spatial parallel mechanism models of the human knee joint: an experiment-based assessment.

In-depth comprehension of human joint function requires complex mathematical models, which are particularly necessary in applications of prosthesis design and surgical planning. Kinematic models of the knee joint, based on one-degree-of-freedom equivalent mechanisms, have been proposed to replicate the passive relative motion between the femur and tibia, i.e., the joint motion in virtually unloaded conditions. In the mechanisms analysed in the present work, some fibres within the anterior and posterior cruciate and medial collateral ligaments were taken as isometric during passive motion, and articulating surfaces as rigid. The shapes of these surfaces were described with increasing anatomical accuracy, i.e. from planar to spherical and general geometry, which consequently led to models with increasing complexity. Quantitative comparison of the results obtained from three models, featuring an increasingly accurate approximation of the articulating surfaces, was performed by using experimental measurements of joint motion and anatomical structure geometries of four lower-limb specimens. Corresponding computer simulations of joint motion were obtained from the different models. The results revealed a good replication of the original experimental motion by all models, although the simulations also showed that a limit exists beyond which description of the knee passive motion does not benefit considerably from further approximation of the articular surfaces.

Helical axis calculation based on Burmester theory: experimental comparison with traditional techniques for human tibiotalar joint motion.

In prosthetics and orthotics design, it is sometimes necessary to approximate the multiaxial motion of several human joints to a simple rotation about a single fixed axis. A new technique for the calculation of this axis is proposed, originally based on Burmester's theory. This was compared with traditional approaches based on the mean and finite helical axes. The three techniques were assessed by relevant optimal axis estimation in in vitro measurements of tibiotalar joint motion. A standard jig and radiostereometry were used in two anatomical specimens to obtain accurate measurements of joint flexion. The performance of each technique was determined by comparing the motion based on the resulting axis with the experimental data. Random noise with magnitude typically similar to that of the skin motion was also added to the measured motion. All three techniques performed well in identifying a single rotation axis for tibiotalar joint motion. Burmester's theory provides an additional method for human joint motion analysis, which is particularly robust when experimental data are considerably error affected.

A new one-DOF fully parallel mechanism for modelling passive motion at the human tibiotalar joint.

Knowledge on how ligaments and articular surfaces guide passive motion at the human ankle joint complex is fundamental for the design of relevant surgical treatments. The paper presents a possible improvement of this knowledge by a new kinematic model of the tibiotalar articulation. Passive motion, i.e. in virtually unloaded conditions, was captured in vitro in four lower leg specimens by means of a surgical navigation system with cluster of active markers attached to the tibia and talus. The anatomical geometry of the passive structures, i.e. articular surfaces and attachment areas of the ligaments, were taken by digitisation with a pointer. An equivalent spatial mechanism for the passive motion simulation was defined by three sphere-to-sphere contact points and two rigid links. These contact points were identified at the lateral talo-fibular articulation and at the medial and lateral aspects of the articulation between tibial mortise and trochlea tali. The two rigid links were identified by the isometric fibres at the calcaneofibular and tibiocalcaneal ligaments. An optimisation algorithm was developed for the identification of the final geometrical parameters resulting from an iterative refining process, which targets best matching between model predictions and corresponding experimental measurements of the spatial motion. The specimen-specific equivalent spatial mechanisms replicated the original passive motion very well, with mean discrepancies in position smaller than 2.5 mm and in rotation smaller than 1 degrees . The study demonstrates that the articular surfaces and the ligaments, acting together as a mechanism, control the passive kinematics of the ankle joint.

Mathematical models of passive motion at the human ankle joint by equivalent spatial parallel mechanisms.

The paper presents a theoretical model of the ankle joint, i.e. tibio-talar articulation, which shows how the articular surfaces and the ligaments, acting together as a mechanism, can control the passive kinematics of the joint. The authors had previously shown that, in virtually unloaded conditions, the ankle behaves as a single degree-of-freedom system, and that two ligament fibres remain nearly isometric throughout the flexion arc. Two different equivalent spatial parallel mechanisms together with corresponding kinematic models were formulated. These assumed isometricity of fibres within the calcaneal-fibular and tibio-calcaneal ligaments and rigidity of the articulating surfaces, taken as three sphere-plane contacts in one model, and as a single spherical pair in the other. Geometry parameters for the models were obtained from three specimens. Motion predictions compare quite well with the measured motion of the specimens. The differences are accounted for by the simplifications adopted to represent the complex anatomical structures, and might be reduced by future more realistic representations of the natural articular surfaces.

[Cat scratch pneumonia: a case report]. / Un caso di polmonite secondaria a graffio di gatto.

Pasteurella multocida infections can be caused by scratches or bites of many animals including pets. An unrecognized infection can lead to severe complications such as arthritis, osteomyelitis, respiratory infections and even meningitis or endocarditis. We present the case of a woman affected by soft tissue infection caused by Pasteurella multocida complicated by bacteremia and pneumonia.

Mechanics of the anterior drawer test at the ankle: the effects of ligament viscoelasticity.

The anterior drawer test at the human ankle joint is a routine clinical examination. The relationship between the mechanical response of this joint and the flexion angle was elucidated by a recent mathematical model, using purely elastic mechanical characteristics for the ligament fibres. The objective of the present work was to assess the effect of ligament viscoelasticity on the force response of the ankle joint for anterior displacements of the foot relative to the tibia, at different ankle flexion positions. A viscoelastic model of the ligaments from the literature was included in the recently proposed mathematical model. Drawer tests were simulated at several flexion angles and for increasing velocities of the imposed anterior displacement. The stiffness of the model ankle joint increased only modestly with velocity. The response force found for a 6mm displacement at 20 degrees plantarflexion increased by only 13% for a one hundred-fold increase in velocity from 0.1 to 10 mm/s. The flexion angle was confirmed as the most influential parameter in the mechanical response of the ankle to anterior drawer test.

Mathematical model for pre-operative planning of linear and closing-wedge metatarsal osteotomies for the correction of hallux valgus.

First-metatarsal osteotomy is performed for an abnormal intermetatarsal angle and severe hallux valgus deformity. The metatarsal head is slid along the osteotomy and fixed with a Kirschner wire to achieve angular and linear realignment with respect to the other metatarsals. When reduction of joint subluxation is also sought, a bone wedge is removed. A mathematical model and a corresponding computer-based tool were developed for pre-operative planning of the optimum surgical solution. Standard intermetatarsal angle correction, head-to-sesamoids re-alignment, joint subluxation reduction and metatarsal length adjustment were all pursued. A standard pre-surgical dorso-plantar radiograph of the patient, with an additional metal ball for calculation of X-ray magnification, was necessary to analyse the original and final geometrical configurations. For the first time, expected bone loss and wire diameter were also considered. The angles of bone cuts and the amount of sliding along these cuts were calculated by the model according to the surgical goal. All the resulting geometrical parameters, both in the pre- and planned post- operative configuration, were provided in graphical and tabular form. In a change from former qualitative analysis of radiograms, the surgeon can now enter the operating theatre with a detailed plan of the goal to be achieved.

Ligament fibre recruitment and forces for the anterior drawer test at the human ankle joint.

Although the anterior drawer test at the ankle joint is commonly used in routine clinical practice, very little is known about the sharing of load between the individual passive structures and the joint response at different flexion angles.A mathematical model of the ankle joint was devised to calculate ligament fibre recruitment and load/displacement curves at different flexion angles. Ligaments were modelled as three-dimensional arrays of fibres, and their orientations at different flexion angles were taken from a previously validated four-bar-linkage model in the sagittal plane. A non-linear stress/strain relationship was assumed for ligament fibres and relevant mechanical parameters were taken from two reports in the literature. Talus and calcaneus were assumed to move as a single rigid body. Antero/distal motion of the talus relative to the tibia was analysed. The ankle joint was found to be stiffer at the two extremes of the flexion range, and the highest laxity was found around the neutral position, confirming previous experimental works. With a first dataset, a 20N anterior force produced 4.3, 5.5, and 4.4mm displacement respectively at 20 degrees plantarflexion, at neutral, and at 20 degrees dorsiflexion. At 10 degrees plantarflexion, for a 6mm displacement, 65% of the external force was supported by the anterior talofibular, 11% by the deep anterior tibiotalar and 5.5% by the tibionavicular ligament. Corresponding results from a second dataset were 1.4, 2.4 and 1.8mm at 40N force, and 80%, 0% and 2% for a 3mm displacement. A component of the contact force supported the remainder.

Response of bovine endothelial cells to FGF-2 and VEGF is dependent on their site of origin: Relevance to the regulation of angiogenesis.

Angiogenesis, the formation of new capillary blood vessels, occurs almost exclusively in the microcirculation. This process is controlled by the interaction between factors with positive and negative regulatory activity. In this study, we have compared the effect of two well described positive regulators, vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (FGF-2) on bovine adrenal cortex-derived microvascular endothelial (BME) and bovine aortic endothelial (BAE) cells. The parameters we assessed included (a) cellular reorganization and lumen formation following exposure of the apical cell surface to a three-dimensional collagen gel; (b) organization of the actin cytoskeleton; (c) expression of thrombospondin-1 (TSP-1), an endogenous negative regulator of angiogenesis; and (d) extracellular proteolytic activity mediated by the plasminogen activator (PA)/plasmin system. We found that (a) collagen gel overlay induces rapid reorganization and lumen formation in BME but not BAE cells; (b) FGF-2 but not VEGF induced dramatic reorganization of actin microfilaments in BME cells, with neither cytokine affecting BAE cells; (c) FGF-2 decreased TSP-1 protein and mRNA expression in BME cells, an effect which was specific for FGF-2 and BME cells, since TSP-1 protein levels were unaffected by VEGF in BME cells, or by FGF-2 or VEGF in BAE cells; (d) FGF-2 induced urokinase-type PA (uPA) in BME and BAE cells, while VEGF induced uPA and tissue-type PA in BME cells with no effect on BAE cells. Taken together, these findings reveal endothelial cell-type specific responses to FGF-2 and VEGF, and point to the greater specificity of these cytokines for endothelial cells of the microvasculature than for large vessel (aortic) endothelial cells. Furthermore, when viewed in the context of our previous observation on the synergistic interaction between VEGF and FGF-2, our present findings provide evidence for complementary mechanisms which, when acting in concert, might account for the synergistic effect.