LE INFEZIONI DI CRANIOPLASTICA: BASI SPERIMENTALI PER LA SOSTITUZIONE IMMEDIATA DEI SOSTITUTI CRANICI INFETTI IN RELAZIONE ALLE DIFFERENTI SPECIE BATTERICHE ED ALL'EVIDENZA CLINICA

Le infezioni di cranioplastica rappresentano una delle pià complesse sfide della moderna neurochirurgia. Il loro trattamento presuppone un complesso equilibrio fra strategia di trattamento medico, revisione chirurgica, decisioni in merito alla possibilitò in caso di recidive multiple, di optare per procedure non convenzionali. Il miglioramento delle terapie antibiotiche in questo campo non ha fornito i risultati sperati, poichè si è accompagnato ad una progressiva comparsa di germi ad elevata resistenza in grado di formare biofilm . Scopo di questo lavoro è stato quello di investigare le affinità di proliferazione di diversi germi multiresistenti sulle quattro tipologie principali di materiali da cranioplastica usati, per poi confrontare i risultati del trattamento in laboratorio e sull'umano. Abbiamo considerato 4 germi, la Klebsiella Pneumoniae, l'Acinetobacter Baumanii, la Pseudomonas Aeruginosa e lo Stafilococco Aureo, come già detto tutti multiresistenti, con senbilità ad una sola famiglia antibiotica. Siamo partiti per lo Stafilococco dal materiale di crescita maggiore (idrossiapatite), dal quale abbiamo poi provveduto ad infettare gli altri materiali (resina acrilica, PEEK, Titanio) e ancora una volta l'idrossiapatite stessa, testata senza e con terapia antibiotica. Lo stafilococco ha mostrato una affinità specifica per l'idrossiapatite, modificata solo dalla terapia antibiotica. La Klebsiella, nelle stesse condizioni, ha mostrato di preferire il PEEK, seguito dal titanio, con scarsa affinità al contrario per l'idrossiapatite. La Pseudomonas ha mostrato una tendenza ad affinità verso il PEEK ed il titanio, sebbene non costante, laddove al contrario l'Acinetobacter è risultato essere in grado di crescere aspecificamente su qualunque terreno. In clinica, questi dati sono stati confermati, mostrando come nelle infezioni da Stafilococco e Klebsiella la sostituzione immediata del materiale infetto a maggiore affinità con uno a bassa affinità, supportata dalla terapia antibiotica, abbia permesso di non lasciare il paziente privo di copertura cranica, indipendentemente dalla severità dell'infezione. Al contrario, Pseudomonas ed Acinetobacter si sono mostrati particolarmente resistenti, lasciando scarse ( nel caso di Penudomonasd) e nessuna (per Acinetobacter) possibilità di effettuare la stessa procedura con successo. Questi risultati rappresentano solo una fase preliminare, basata sulla numerificazione delle colonie sviluppate, pertanto necessiteranno di essere sostanziati da un ulteriore approfondimento con coloranti per l'attività metabolica ed una eventuale valutazione di microscopia confocale per identificare le modalità di crescita batterica.Cranioplasty infections are one of the major challenges of modern Neurosurgery. Their treatment requires a complex balance between medical and surgical strategies, especially in case of frequent relapses, requiring unconventional procedures. The improvement of antibiotic therapy did not meet operators’ expectations, due to the appearance of multidrug resistant germs, able to form biofilm. Aim of this work was to investigate the growth preferences of some MDR species on the 4 more common cranioplasty materials, to be then compared to human results. Four germs were selected, Klebsiella Pneumoniae, Acinectobacter Baumanii, Pseudomonas Aeruginosa, Staphylococcus Aureus, sensitive to treatment with only one antibiotic. Staphylococcus showed preference for growth in Hydroxyapathite and when allowed to grow on the same material and on acrylic resin, PEEK and titanium, its preference remained unchanged. Klebsiella behaved similarly , but preferring PEEK and titanium. On the counterside, Pseudomonas, although showing a propensity for growth on PEEK, was also effective on titanium and hydroxyapathite, where Acinetobacter was able to grow similarly everywhere. We wanted to know if patients presenting with an active infection of their cranioplasty could successfully undergo its immediate replacement. Our results suggested that this could happen with Stph Aureus and Klebsiella, in some case with Pseudomonas, never with Acinetobacter. Data from our clinical series confirmed these results. Although the capacity of surgery and antibiotics to inferfere with bacterial growth on cranioplasty can be confirmed only for some species, further studies requiring a metabolic-based evaluation and confocal microscopy observation of bacterial growth will be needed to substantiate these data

Leptin activates the anandamide hydrolase promoter in human T lymphocytes through STAT3

Physiological concentrations of leptin stimulate the activity of the endocannabinoid-degrading enzyme anandamide hydrolase (fatty acid amide hydrolase, FAAH) in human T lymphocytes up to approximately 300% over the untreated controls. Stimulation of FAAH occurred through up-regulation of gene expression at transcriptional and translational levels and involved binding of leptin to its receptor with an apparent dissociation constant (K(d)) of 1.95 +/- 0.14 nm and maximum binding (B(max)) of 392 +/- 8 fmol x mg protein(-1). Leptin binding to the receptor triggered activation of STAT3 but not STAT1 or STAT5 or the mitogen-activated protein kinases p38, p42, and p44. Peripheral lymphocytes of leptin knock-out (ob/ob) mice showed decreased FAAH activity and expression (approximately 25% of the wild-type littermates), which were reversed to control levels by exogenous leptin. Analysis of the FAAH promoter showed a cAMP-response element-like site, which is a transcriptional target of STAT3. Consistently, mutation of this site prevented FAAH activation by leptin in transient expression assays. Electrophoretic mobility shift and supershift assays further corroborated the promoter activity data. Taken together, these results suggest that leptin, by up-regulating the FAAH promoter through STAT3, enhances FAAH expression, thus tuning the immunomodulatory effects of anandamide. These findings might also have critical implications for human fertility

Progesterone activates fatty acid amide hydrolase (FAAH) promoter in human T lymphocytes through the transcription factor Ikaros. Evidence for a synergistic effect of leptin.

Physiological concentrations of progesterone stimulate the activity of the endocannabinoid-degrading enzyme fatty acid amide hydrolase (FAAH) in human T lymphocytes, up to a ∼270% over the untreated controls. Stimulation of FAAH occurred through up-regulation of gene expression at transcriptional and translational level and was specific. Indeed, neither the activity of the anandamide-synthesizing N-acyltransferase and phospholipase D, nor the activity of the anandamide transporter, nor the binding to cannabinoid receptors were affected by progesterone under the same experimental conditions. The activation of FAAH by progesterone was paralleled by a decrease (down to 60%) of the cellular levels of anandamide and involved increased nuclear levels of the transcription factor Ikaros. Analysis of the FAAH promoter showed an Ikaros binding site, and mutation of this site prevented FAAH activation by progesterone in transient expression assays. Electrophoretic mobility shift and supershift assays further corroborated the promoter activity data. Furthermore, the effect of progesterone on FAAH promoter was additive to that of physiological amounts of leptin, which binds to a cAMP response element-like site in the promoter region. Taken together, these results suggest that progesterone and leptin, by up-regulating the FAAH promoter at different sites, enhance FAAH expression, thus tuning the immunomodulatory effects of anandamide. These findings might also have critical implications for human fertility

Evaluation of prognostic preoperative factors in patients undergoing surgery for spinal metastases: Results in a consecutive series of 81 cases

Background: Surgical treatment of spinal metastases should be tailored to provide pain control, neurological deficit improvement, and vertebral stability with low operative morbidity and mortality. The aim of this study was to analyze the predictive value of some preoperative factors on overall survival in patients undergoing surgery for spinal metastases. Methods: We retrospectively analyzed a consecutive series of 81 patients who underwent surgery for spinal metastases from 2015 and 2021 in the Clinic of Neurosurgery of Ancona (Italy). Data regarding patients’ baseline characteristics, preoperative Karnofsky Performance Status Score (KPS), and Frankel classification grading system, histology of primary tumor, Tokuhashi revised and Tomita scores, Spine Instability Neoplastic Score, and Epidural Spinal Cord Compression Classification were collected. We also evaluated the interval time between the diagnosis of the primary tumor and the onset of spinal metastasis, the type of surgery, the administration of adjuvant therapy, postoperative pain and Frankel grade, and complications after surgery. The relationship between patients’ overall survival and predictive preoperative factors was analyzed by the Kaplan–Meier method. For the univariate and multivariate analysis, the log-rank test and Cox regression model were used. P ≤ 0.05 was considered as statistically significant. Results: After surgery, the median survival time was 13 months. In our series, the histology of the primary tumor (P < 0.001), the Tomita (P < 0.001) and the Tokuhashi revised scores (P < 0.001), the preoperative KPS (P < 0.001), the adjuvant therapy (P < 0.001), the postoperative Frankel grade (P < 0.001), and the postoperative pain improvement (P < 0.001) were significantly related to overall survival in the univariate analysis. In the multivariate analysis, the Tomita (P < 0.001), Tokuhashi revised scores (P < 0.001), and the adjuvant therapy were confirmed as independent prognostic factors. Conclusion: These data suggest that patients with limited extension of primitive tumor and responsive to the adjuvant therapy are the best candidates for surgery with better outcome

Retention of nativelike conformation by proteins embedded in high external electric fields.

In this Communication, we show that proteins embedded in high external electric fields are capable of retaining a nativelike fold pattern. We have tested the metalloprotein azurin, immobilized onto SiO2 substrates in air with proper electrode configuration, by applying static fields up to 106–107V∕m. The effects on the conformational properties of protein molecules have been determined by means of intrinsic fluorescence measurements. Experimental results indicate that no significant field-induced conformational alteration occurs. Such results are also discussed and supported by theoretical predictions of the inner protein fields

Precursor and mature NGF live tracking: one versus many at a time in the axons

The classical view of nerve growth factor (NGF) action in the nervous system is linked to its retrograde axonal transport. However, almost nothing is known on the trafficking properties of its unprocessed precursor proNGF, characterized by different and generally opposite biological functions with respect to its mature counterpart. Here we developed a strategy to fluorolabel both purified precursor and mature neurotrophins (NTs) with a controlled stoichiometry and insertion site. Using a single particle tracking approach, we characterized the axonal transport of proNGF versus mature NGF in living dorsal root ganglion neurons grown in compartmentalized microfluidic devices. We demonstrate that proNGF is retrogradely transported as NGF, but with a lower flux and a different distribution of numbers of neurotrophins per vesicle. Moreover, exploiting a dual-color labelling technique, we analysed the transport of both NT forms when simultaneously administered to the axon tips

Precursor and mature NGF live tracking: one versus many at a time in the axons

The classical view of nerve growth factor (NGF) action in the nervous system is linked to its retrograde axonal transport. However, almost nothing is known on the trafficking properties of its unprocessed precursor proNGF, characterized by different and generally opposite biological functions with respect to its mature counterpart. Here we developed a strategy to fluorolabel both purified precursor and mature neurotrophins (NTs) with a controlled stoichiometry and insertion site. Using a single particle tracking approach, we characterized the axonal transport of proNGF versus mature NGF in living dorsal root ganglion neurons grown in compartmentalized microfluidic devices. We demonstrate that proNGF is retrogradely transported as NGF, but with a lower flux and a different distribution of numbers of neurotrophins per vesicle. Moreover, exploiting a dual-color labelling technique, we analysed the transport of both NT forms when simultaneously administered to the axon tips

Azurin for Biomolecular Electronics: a Reliability Study

The metalloprotein azurin, used in biomolecular electronics, is investigated with respect to its resilience to high electric fields and ambient conditions, which are crucial reliability issues. Concerning the effect of electric fields, two models of different complexity agree indicating an unexpectedly high robustness. Experiments in device-like conditions confirm that no structural modifications occur, according to fluorescence spectra, even after a 40-min exposure to tens of MV/m. Ageing is then investigated experimentally, at ambient conditions and without field, over several days. Only a small conformational rearrangement is observed in the first tens of hours, followed by an equilibrium state

Exploiting Reaction-Diffusion Conditions to Trigger Pathway Complexity in the Growth of a MOF

Coordination polymers (CPs), including metal-organic frameworks (MOFs), are crystalline materials with promising applications in electronics, magnetism, catalysis, and gas storage/separation. However, the mechanisms and pathways underlying their formation remain largely undisclosed. Herein, we demonstrate that diffusion-controlled mixing of reagents at the very early stages of the crystallization process (i.e., within ≈40 ms), achieved by using continuous-flow microfluidic devices, can be used to enable novel crystallization pathways of a prototypical spin-crossover MOF towards its thermodynamic product. In particular, two distinct and unprecedented nucleation-growth pathways were experimentally observed when crystallization was triggered under microfluidic mixing. Full-atom molecular dynamics simulations also confirm the occurrence of these two distinct pathways during crystal growth. In sharp contrast, a crystallization by particle attachment was observed under bulk (turbulent) mixing. These unprecedented results provide a sound basis for understanding the growth of CPs and open up new avenues for the engineering of porous materials by using out-of-equilibrium conditions

Posterior Titanium Screw Fixation without Debridement of Infected Tissue for the Treatment of Thoracolumbar Spontaneous Pyogenic Spondylodiscitis

Study DesignRetrospective study.PurposeThe aim of our study was to analyze the safety and effectiveness of posterior pedicle screw fixation for treatment of pyogenic spondylodiscitis (PSD) without formal debridement of the infected tissue.Overview of LiteraturePosterior titanium screw fixation without formal debridement of the infected tissue and anterior column reconstruction for the treatment of PSD is still controversial.MethodsFrom March 2008 to June 2013, 18 patients with PSD underwent posterior titanium fixation with or without decompression, according to their neurological deficit. Postero-lateral fusion with allograft transplantation alone or bone graft with both the allogenic bone and the autologous bone was also performed. The outcome was assessed using the visual analogue scale (VAS) for pain and the Frankel grading system for neurological status. Normalization both of C-reactive protein (CRP) and erythrocyte sedimentation rate was adopted as criterion for discontinuation of antibiotic therapy and infection healing. Segmental instability and fusion were also analyzed.ResultsAt the mean follow-up time of 30.16 months (range, 24–53 months), resolution of spinal infection was achieved in all patients. The mean CRP before surgery was 14.32±7.9 mg/dL, and at the final follow-up, the mean CRP decreased to 0.5±0.33 mg/dL (p <0.005). Follow-up computed tomography scan at 12 months after surgery revealed solid fusion in all patients. The VAS before surgery was 9.16±1.29 and at the final follow-up, it improved to 1.38±2.03, which was statistically significant (p <0.05). Eleven patients out of eighteen (61.11%) with initial neurological impairment had an average improvement of 1.27 grades at the final follow-up documented with the Frankel grading system.ConclusionsPosterior screw fixation with titanium instrumentation was safe and effective in terms of stability and restoration of neurological impairment. Fixation also rapidly reduced back pain