Spin-lattice relaxation time in water/graphene-oxide dispersion.

We present the results of the calculations of the spin-lattice relaxation time of water in contact with graphene oxide by means of all-atom molecular dynamics simulations. We fully characterized the water-graphene oxide interaction through the calculation of the relaxation properties of bulk water and of the contact angle as a function of graphene oxide oxidation state and comparing them with the available experimental data. We then extended the calculation to investigate how graphene oxide alters the dynamical and relaxation properties of water in different conditions and concentrations. We show that, despite the diamagnetic nature of the graphene oxide, the confining effects of the bilayers strongly affect the longitudinal relaxation properties of interfacial water, which presents a reduced dynamics due to hydrogen bonds with oxygen groups on graphene oxide. This property makes graphene oxide an interesting platform to investigate water dynamics in confined geometries and an alternative contrast-agent for magnetic resonance imaging applications, especially in view of the possibility to functionalize graphene oxide from theranostic perspectives.

[Long-term audition results in patients with chronic endolymphatic hydrops after selective vestibular neurotomy and endolymphatic sac surgery]. / Risultati uditivi a lungo termine in pazienti con idrope endolinfatica cronica dopo neurotomia vestibolare selettiva e trattamento del sacco endolinfatico.

The purpose of the present study was to evaluate the long-term auditory results in the ears of patients suffering from unilateral Ménière's disease (Md) who had undergone retrolabyrinthine vestibular neurotomy (RVN) associated with endolymphatic sac (ES) surgery. Retrospective evaluation was performed on 45 patients with unilateral Md who had undergone RVN between 1982-1997. All patients had previously been treated with medical therapy for at least 6 months without showing any response. The forms of ES surgery performed were as follows: simple ES decompression (ESD) in 15 patients, chronic endolymphatic mastoid shunt (EMS) using a sylastic sheet in 15 ears and ES exclusion (ESE) of the proximal section in the remaining 15 patients. Evaluation of the results was performed using the parameters indicated by the "Committee on Hearing and Equilibrium"--AAO-HNS 1995. Comparison of the average post-operative and preoperative PTAs revealed a worsening of 9.2 dB (sd: +/- 17.1) in the ESE group. This variation was statistically significant (p < 0.05). When the individual patients were evaluated, the PTA remained unchanged in 10 cases (67%) in the ESD group, in 13 (87%) in the EMS group and in 10 (67%) in the ESE group. In no case did hearing improve. Statistical analysis did not reveal any significant difference between the three groups of patients. Tinnitus, present prior to surgery in all patients, disappeared or improved in 6 patients (40%) in the ESD group, in 6 (40%) of the EMS group and in 5 (33%) of the ESE group. The differences between groups were not significant. The sensation of plugged ears, present prior to surgery in 11 patients in the ESD and EMS groups and in 13 patients in the ESE group disappeared or improved respectively in 9 (82%), 10 (91) and 11 (85%) of the patients. The 10 remaining patients who did not have the sensation of plugged ears prior to surgery did not refer its appearance after surgery. Again for this symptom the difference between groups was not significant. The results of this research would appear to indicate that in patients with Md, evolution of the hearing symptoms observed after RVN can be improved by applying an EMS. This finding must be validated in a larger sampling.

[Acoustic neuroma: clinical-functional finding, results and surgical complication]. / Il neurinoma dell'acustico: reperti clinico-funzionali, risultati e complicanze chirurgiche.

The present work provides clinical-functional findings, results and surgical complications observed in a consecutive series of 100 subjects with acoustic neuroma (AN). Analysis of the data has made it possible to draw some important conclusions. Compromised hearing is found in 90% of the ears affected by AN. Indeed the percentage of normal hearing in such cases does not exceed 5%. There is, however, no clear correlation between degree of hearing and tumor size. The symptoms of AN do not always present unilateral or asymmetrical hearing loss, unilateral tinnitus and/or dizziness. At times AN presents atypical symptoms and can even be asymptomatic. Sudden onset of unilateral hearing loss, acute vertigo, persistent monolateral tinnitus and even isolated symptoms of the V or VI cranial nerve should lead one to suspect AN. Only by applying the diagnosis of suspected AN in a large number of cases is it possible to lower the time gap between the onset of symptoms and the definitive diagnosis of AN, increasing the number of cases diagnosed while the AN is still small. Auditory brainstem responses (ABR) are still the means of choice for screening and following up subjects where AN is suspected. Reduced ABR sensitivity reported in the literature for intracanal ANs must induce further testing with magnetic resonance imaging with gadolinium in all subjects where an AN is suspected, even when the ABR is normal. Recording of transient evoked otoacoustic emissions in the presence and in the absence of contralateral white noise has proved to be a simple, inexpensive, non-invasive test for the diagnosis of suspected retrocochlear pathologies. A deficit in vestibular function is most frequently encountered when the AN is already quite large and an alteration in the smooth pursuit test is only found when the AN involves the brainstem. These data have led us to conclude that vestibular reflex studies do not play any role in early diagnosis of AN. Surgical exeresis is the treatment of choice in those cases where "watch and scan" (only hearing ear in the absence of neurological complications; AN < 0.5 cm in the ponto-cerebellar angle, particularly in elderly patients) is not indicated. The enlarged translabyrinthine approach is indicated in all cases of AN, no matter what the tumor size and extent of pre-operative hearing. Promptly and correctly treating intra and postoperative complications, most frequently encountered in patients with AN > 2 cm, reduces the mortality and morbidity to a minimum. Modern otological microsurgery and monitoring techniques make it possible to preserve the VIIth facial nerve in more than 90% of the ears, consequently preserving or nearly preserving normal VIIth nerve function 1 year after surgery in at least three out of four patients. No matter what approach is used, hearing can be preserved measurably in approximately 50% of the ears undergoing surgery and to a socially useful or nearly useful level in a significantly lower proportion of patients. In this regard the most satisfactory results are obtained when preoperative hearing is normal and the AN is < 2 cm.

The value of CT scans in improving laryngoscopy in patients with laryngeal cancer.

This retrospective study assessed the value of computed tomography (CT) scan with contrast in improving the staging accuracy of indirect and direct laryngoscopy. We compared the preoperative staging obtained by the two latter procedures with postoperative histopathological findings in 187 patients operated on for laryngeal cancer. Of these cancers, 98 were supraglottic, 82 glottic and 7 subglottic in origin. The staging accuracy of laryngoscopy was 51.3% and CT was 70.1%. When the two procedures were combined, the staging accuracy was 80.2%. The accuracy of the CT increased from glottic to supraglottic to subglottic tumors, although the accuracy of laryngoscopy decreased in the same direction. Laryngoscopy alone tended to understage larger tumors (pT3 and pT4), whereas CT underestimated the smaller ones (pT1 and pT2). Our data suggest that in order to plan the best treatment both laryngoscopy and CT should be used in making the diagnosis.