Improvement of spatial learning and memory deficits by intranasal administration of human olfactory ecto-mesenchymal stem cells in an Alzheimer's disease rat model.

Mesenchymal stem cells therapy provides a new perspective of therapeutic approaches in the treatment of neurodegenerative diseases. The present study aimed to investigate the effects of intranasally transplanted human "olfactory ecto-mesenchymal stem cells" (OE-MSCs) in Alzheimer's disease (AD) rats. In this study, we isolated OE-MSCs from human olfactory lamina propria and phenotypically characterized them using immunocytochemistry and flow cytometry. The undifferentiated OE-MSCs were transplanted either by intranasal (IN) or intrahippocampal (IH) injection to rat models of AD, which were induced by injecting amyloid-beta (Aß) intrahippocampally. Behavioral, histological, and molecular assessments were performed after a three-month recovery period. Based on the results, intranasal administration of OE-MSCs significantly reduced Aß accumulation and neuronal loss, improved learning and memory impairments, and increased levels of BDNF (brain-derived neurotrophic factor) and NMDAR (N-methyl-D-Aspartate receptors) in the AD rat model. These changes were more significant in animals who received OE-MSCs by intranasal injection. The results of this study suggest that OE-MSCs have the potential to enhance cognitive function in AD, possibly mediated by BDNF and the NMDA receptors.

Electrophysiological and molecular changes following neuroprotective placental protein administration on tinnitus-induced rats.

Objective: Despite 6%-20% of the adult population suffering from tinnitus, there is no standard treatment for it. Placenta extract has been used for various therapeutic purposes, including hearing loss. Here, we evaluate the effect of a novel neuroprotective protein composition (NPPC) extract on electrophysiological and molecular changes in the medial geniculate body (MGB) of tinnitus-induced rats. Methods: To evaluate the protein analysis by western blot, the rats were divided into three groups: (1) saline group (intraperitoneal injection of 200 mg/kg saline twice a day for 28 consecutive days, (2) chronic Na-Sal group received sodium salicylate as in the first group, and (3) chronic treatment group (received salicylate 200 mg/kg twice daily for 2 weeks, followed by 0.4 mg NPPC daily from day 14 to day 28). Single-unit recordings were performed on a separate group that was treated as in group 4. Gap-prepulse inhibition of the acoustic startle (GPIAS) and pre-pulse inhibition (PPI) was performed to confirm tinnitus in all groups at the baseline, 14th and 28th days. Results: Western blot analysis showed that the expression of γ-Aminobutyric acid Aα1 subunit (GABA Aα1), N-methyl-d-aspartate receptor subtype 2B (NR2B or NMDAR2B), α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors subunit GluR1 (GluR1), and α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors subunit GluR2 (GluR2) decreased after Na-Sal injection, while NPPC upregulated their expression. MGB units in rats with tinnitus showed decreased spontaneous firing rate, burst per minute, and a spike in a burst. After NPPC administration, neural activity patterns showed a significant positive effect of NPPC on tinnitus. Conclusion: NPPC can play an effective role in the treatment of tinnitus in salicylate-induced rats, and MGB is one of the brain areas involved in these processes. Level of Evidence: NA.

The human neuroprotective placental protein composition suppressing tinnitus and restoring auditory brainstem response in a rodent model of sodium salicylate-induced ototoxicity.

The effect of neuroprotective placental protein composition (NPPC) on the suppression of tinnitus and the restoration of the auditory brainstem response (ABR) characteristics was explored in tinnitus-induced rats. The animals were placed into two groups: (1) the study group, rats received sodium salicylate (SS) at the dose of 200 mg/kg twice a day for two weeks, and then 0.4 mg of the NPPC per day, between the 14th and 28th days, (2) the placebo group, rats received saline for two weeks, and then the NPPC alone between the 14th and 28th days. The gap pre-pulse inhibition of the acoustic startle (GPIAS), the pre-pulse inhibition (PPI), and the ABR assessments were performed on animals in both groups three times (baseline, day 14, and 28). The GPIAS value declined after 14 consecutive days of the SS injection, while NPPC treatment augmented the GPIAS score in the study group on the 28th day. The PPI outcomes revealed no significant changes, indicating hearing preservation after the SS and NPPC administrations. Moreover, some changes in ABR characteristics were observed following SS injection, including (1) higher ABR thresholds, (2) lowered waves I and II amplitudes at the frequencies of 6, 12, and 24 kHz and wave III at the 12 kHz, (3) elevated amplitude ratios, and (4) prolongation in brainstem transmission time (BTT). All the mentioned variables returned to their normal values after applying the NPPC. The NPPC use could exert positive therapeutic effects on the tinnitus-induced rats and improve their ABR parameters.

The Therapeutic Outcome of Sialendoscopy in Patients with Sialoadenitis.

Introduction: Recent advances have led to the development of sialendoscopy, an accurate, minimally invasive procedure with high diagnostic and therapeutic capabilities in treating sialolithiasis. This study aimed to evaluate the results and complications of sialendoscopy in patients suffering from sialoadenitis. Materials and Methods: This study was a prospective interventional case series study on patients with sialoadenitis due to sludge or stone formation preoperatively confirmed by sonography or computed tomography (CT) scanning. Diagnostic sialendoscopy was performed, and the presence of stenosis, sludge, or stones inside the gland or duct was examined, and surgery was done. During follow-up time (18.8 ± 7.4 months), recurrence of symptoms, the need for reoperation, and postoperative complications were also assessed. Results: The sialendoscopy was performed in 51 patients, including 55 glands. Forty-five Patients (88.2%) reported pain relief, and 46 patients (90.2%) reported that the treatment using sialendoscopy was better than conservative methods. The duct restenosis also occurred in one patient requiring open surgery. In assessing the main factors predicting the need for reoperation, the site of involvement (parotid versus submandibular glands) and the size of the stone were identified as the main determinants. The best cut-off value for stone size in predicting reoperation requirement was 7.0mm, with a sensitivity of 100% and a specificity of 85.7%. Conclusion: Intraoperative sialendoscopy is a successful diagnostic and therapeutic tool with minimal postoperative complications in salivary gland duct involvement patients.

Complications and outcomes of cochlear implantation in children younger than 12 months: A multicenter study.

OBJECTIVES: Evidence suggests that Cochlear Implantation (CI) is a beneficial approach for auditory and speech skills improvement in children with severe to profound hearing loss. However, it remains controversial if implantation in children <12 months is safe and effective compared to older children. The present study aimed to determine whether children's ages affect surgical complications and auditory and speech development. METHODS: The current multicenter study enrolled 86 children who underwent CI surgery at <12 months of age (group A) and 362 children who underwent implantation between 12 and 24 months of age (group B). The Categories of Auditory Performance (CAP) and Speech Intelligibility Rating (SIR) scores were determined pre-impanation, and "one-year" and "two-year" post-implantation. RESULTS: All children had full insertions of the electrode array. Four complications (overall rate: 4.65%; three minor) occurred in group A and 12 complications (overall rate: 4.41%; nine minor) occurred in group B. We found no statistically significant difference in the complication rates between the groups (p > 0.05). The mean SIR and CAP scores improved over time following CI activation in both groups. However, we did not find significant differences in CAP and SIR scores between the groups across different time points. CONCLUSION: Cochlear implantation in children younger than 12 months is a safe and efficient procedure, providing substantial auditory and speech benefits. Furthermore, rates and nature of minor and major complications in infants are similar to those of children undergoing the CI at an older age.

Assessment of Human Leukocyte Antigen Differences between Smokers with Reinke's Edema and Those with Laryngeal Cancer.

Introduction: The present study aimed to assess human leukocyte antigen (HLA) typing differences between smokers with Reinke's edema and those with laryngeal squamous cell carcinoma (SCC). Materials and Methods: The HLA class I, II alleles were examined in 76 unrelated Iranian patients using low-resolution polymerase chain reaction with the sequence-specific primer (PCR-SSP) method. Results: The frequency of the HLA-A*36 allele and HLA-B*35 was significantly higher in patients with SCC. The frequency of HLA-DRB1*01 alleles in Reinke's edema was significantly higher, as compared to that in others. In the volunteer group, HLA-DRB1*13 and HLA-DRB1*15 were significantly higher. Conclusions: As evidenced by the obtained results, HLA-A*36 was significantly higher in SCC, as compared to that in volunteers and Reinke's edema patients. It can be concluded that being positive for HLA-A*36 increases the chance of SCC by three times. This result should be further investigated in cohort studies conducted on larger samples. Furthermore, HLA-A*24 was significantly higher in the volunteer group, as compared to that in other groups. The HLADRB1*01 was remarkably higher in Reinke's edema, as compared to that in SCC.

Intratympanic corticosteroid injection as a first-line treatment of the patients with idiopathic sudden sensorineural hearing loss compared to systemic steroid: A systematic review and meta-analysis.

OBJECTIVES: The current study aimed to investigate if there is a difference in the use of intratympanic steroid therapy (IST), compared to systemic steroid treatment (SST), as an initial treatment for patients with sudden sensorineural hearing loss (SSNHL) by a meta-analysis design performed on the mean pure-tone average (PTA) improvement and the complete recovery rate. METHODS: A systematic literature review was performed on randomized controlled trials published from 1990 to August 2020 in some databases including PubMed/MEDLINE, Scopus, Embase, Web of Science, Cochrane library/CENTRAL, Ovid, ProQuest, Google Scholar, and clinical trials.gov. The primary outcomes of interest were pure-tone average improvement and complete recovery rates. RESULTS: Six eligible studies with 496 patients (250 patients in the IST group and 246 subjects in the SST group) were included in this study. The pooled standardized mean difference of the PTAs was estimated as 0.07 (95% CI = -0.10 to 0.25; I2 = 0.0%, P = 0.668), and the pooled odds ratio of complete recovery rate was obtained as 1.00 (95% CI = 0.66 to 0.151; I2 = 31.6, P = 0.199). Moreover, the pooled standardized mean difference of pure-tone average for the intratympanic steroid treatment group compared to the patients with oral steroid treatment was 0.07 (95% CI = -0.12 to 0.26; I2 = 0.0%, P = 0.526). CONCLUSIONS: The current study demonstrated that the effect of intratympanic injection of corticosteroid, as a first-line treatment, is not statistically different from the systemic route in improving the hearing outcomes among patients with SSNHL.

Hybrid electrospun scaffolds based on polylactic acid/ PAMAM dendrimer/gemini surfactant for enhancement of synergistic antibacterial ability for biomedical application.

Hybrid electrospun scaffolds based on poly (L-lactic acid) (PLLA)/poly (amidoamine) (PAMAM-G2) dendrimer/gemini surfactant were fabricated for the enhancement of synergistic antibacterial activities. The second generation of poly (amidoamine) (PAMAM-G2) and cationic gemini surfactant were utilized to functionalize the optimum electrospun scaffolds. The gelatination process was utilized to improve the wettability of PLLA scaffolds to extend cell attachment and cell proliferation. PLLA nanofibrous scaffolds were characterized by energy dispersion x-ray, scanning electron microscopy images, mechanical properties, water contact angle, Fourier transform infrared spectroscopy, zeta potential and antibacterial assessment.In vitrocell biocompatibility was evaluated by 3-(4, 5- dimethylthiazoyl-2-yl)-2, 5-diphenyltetrazolium bromide assay and morphology of PC-12 cells cultured on hybrid nanofibrous scaffolds and gelatinized ones. The results indicated that the optimum scaffolds could successfully modify the characteristics of PLLA scaffolds leading to much more appropriate physical and chemical properties. In addition, gelatinized nanofibrous scaffolds reveal more wettability enhancing cell attachment and proliferation. Furthermore, using poly (amidoamine) (PAMAM-G2) and gemini surfactant reveals synergetic antibacterial activity due to the competition between both cationic groups of PAMAM and gemini surfactant. Finally, improved cell adhesion and cell viability on modified scaffolds were confirmed. These favorable properties give a chance for these scaffolds to be used in a wide variety of biomedical applications.

Effect of Lamotrigine on Ouabain-Induced Arrhythmia in Isolated Atria of Guinea Pigs.

Background: Lamotrigine (LTG) is an antiepileptic drug used in the treatment of seizures, mood disorders, and cognitive problems. The cardiac effects of LTG, such as LTG toxicity and SUEDP, have been studied. This is an in vitro study examining the effect of LTG on isolated atria of guinea pigs. Methods: The atria of 21 male Guinea pigs were isolated and stabilized in Krebs-solution and physiologic condition. The rhythm of contraction, contractile force, and heart rate were recorded. In 7 atria, LTG at the doses of 2, 4, 8, and 16 mg/mL were added and the contractile forces and heart rates were recorded and compared together. In the next step, in 14 atria, 8 were pretreated with LTG, and 6 without pretreatment were exposed to ouabain, and the times of the onset of effect, arrhythmia, and asystole were recorded. The statistical comparisons were made by using Student's t test and repeated measure analysis of variance followed by the Bonferroni method. Results: Lamotrigine (4, 8, and 16 mg/mL) significantly decreased the heart rate and contractile force of the isolated guinea pigs' atria (P <.001). Pretreatment with LTG significantly increased the mean time of onset of the effect of ouabain, the onset of ouabain-induced arrhythmia, and time of ouabain-induced asystole (P <.001). Conclusion: LTG reduces the heart rate and contractile force, and also inhibit ouabain induced-arrhythmia of the isolated atria of guinea pigs.

Effects of olfactory training on resting­state effective connectivity in patients with posttraumatic olfactory dysfunction.

The present study investigated if and how the smell training scheme affects resting­state effective connectivity. We focused on connectivity among brain regions that participate in olfactory­related processes, including the piriform cortex, amygdala, orbitofrontal cortex (OFC), insula, and cingulate cortex. Sixteen patients with posttraumatic olfactory dysfunctions between the ages of 18 and 36 years participated in this study. Olfactory performance of subjects was evaluated using the Sniffin' Sticks test kit and then, resting­state functional magnetic resonance imaging (fMRI) was performed. Of the 16 participants, 8 underwent olfactory training for 16 weeks and the remaining 8 did not receive the treatment (the control group). After 16 weeks, participants in both groups underwent the same procedure (smell testing and the MRI examination). Olfactory performance scores were compared between groups using an independent samples t­test. Spectral dynamic causal modeling was applied to resting­state fMRI data to identify alterations in effective connectivity due to the smell training. We found that patients in the treatment group improved in the odor discrimination task and overall olfactory function as compared to the control group. Compared to the control group, patients in the treatment group had increased self­inhibitory connectivity of the OFC and increased excitatory connectivity from the cingulate cortex to the insula. Moreover, the excitatory connectivity from the OFC to the cingulate cortex was found to be weaker following the olfactory training scheme. This study shows that a smell training scheme can cause changes in resting­state effective connectivity parameters that can be attributed to improvements in the odor discrimination task.

Impact of Acamprosate on Chronic Tinnitus: A Randomized-Controlled Trial.

OBJECTIVES: Tinnitus is a common and distressing otologic symptom, with various probable pathophysiologic mechanisms, such as an imbalance between excitatory and inhibitory mechanisms. Acamprosate, generally used to treat alcoholism, is a glutaminergic antagonist and GABA agonist suggested for treating tinnitus. Thus, we aimed to evaluate the efficacy and safety of acamprosate in the treatment of tinnitus. METHODS: The current randomized-controlled trial study included 20 subjects with chronic tinnitus. After performing psycho-acoustic, psychometric and electrophysiological evaluations, all studied tinnitus subjects were randomly divided into two groups of acamprosate and placebo. The first group received oral acamprosate (two tablets of 333 mg/d, three times a day), whereas the second group was given placebo treatment (two tablets, three times a day). After the first 30 days, all evaluations were repeated for the studied groups just in the same manner before the study. Subsequently, the final results of each evaluation were compared together with the baseline values. RESULTS: Nine studied subjects randomly received acamprosate, whereas eleven others received a placebo. There was no significant improvement in the psycho-acoustic tests, except a decrease was observed in the pitch match of tinnitus (P = .039). For those subjects who were receiving acamprosate, a significant reduction was observed in tinnitus handicap inventory (P = .006), tinnitus questionnaire scores (P = .007), and the visual analog scores (P = .007) compared to the placebo group. There was a significant reduction in Action Potential latency (P = .048) as well as an increase in the amplitude of distortion product otoacoustic emissions at 4 kHz (P = .048). CONCLUSIONS: The study results indicated a subjective relief of tinnitus as well as some degree of the electrophysiological improvement at the level of the cochlear and the distal portion of the auditory nerve among the subjects who received the acamprosate. CLINICAL TRIAL REGISTRATION CODE: IRCT2013121115751N1.

Cochlear implantation in children with inner ear malformation: A multicenter study on auditory performance and speech production outcomes.

OBJECTIVES: This multicenter study evaluated the auditory performance and speech production outcomes of cochlear implantation in children with inner ear anomaly and compared the outcomes of patients with different kinds of malformation. METHODS: Cochlear implantation was performed in 107 children with inner ear malformation at four tertiary academic centers. The categories of auditory performance (CAP) and speech intelligibility rating (SIR) scores were evaluated preoperatively and one year and two years postoperatively. RESULTS: Types of inner ear malformation and their frequencies were: incomplete partition type-I, 19 (17.8%) patients; incomplete partition type-II, 31 (29%), common cavity, 17 (15.9%), cochlear hypoplasia, 17 (15.9%), and isolated enlarged vestibular aqueduct (isolated EVA), 23 (21.5%) patients. EVA was the coexisting anomaly in 27(25.2%) subjects. The median CAP and SIR scores improved significantly during the first two years after cochlear implantation in all groups (p-values <0.001 and < 0.001, respectively). No significant difference was seen in CAP and SIR scores of children with different inner ear malformations (p-value = 0.147 and 0.570, respectively) or in patients with isolated EVA compared to coexisting EVA (p-value = 0.538 and 0.075, respectively). CONCLUSION: The median CAP and SIR scores two years after surgery were 5 (Understanding of common phrases without lip-reading) IQR: 4-6, and 3 (Connected speech is intelligible to a listener who concentrates and lip-reads within a known context) IQR: 3-4, respectively. Auditory performance and speech production were significantly improved in all inner ear malformation patient groups, and no significant difference was observed between the scores of patients with different types of anomaly.

Feasibility Assessment of Optical Coherence Tomography-Guided Laser Labeling in Middle Cranial Fossa Approach.

INTRODUCTION: Different approaches have been developed to find the position of the internal auditory canal (IAC) in middle cranial fossa approach. A feasibility study was performed to investigate the combination of cone beam computed tomography (CBCT), optical coherence tomography (OCT), and laser ablation to assist a surgeon in a middle cranial fossa approach by outlining the internal auditory canal (IAC). MATERIALS AND METHODS: A combined OCT laser setup was used to outline the position of IAC on the surface of the petrous bone in cadaveric semi-heads. The position of the hidden structures, such as IAC, was determined in MATLAB software using an intraoperative CBCT scan. Four titanium spheres attached to the edge of the craniotomy served as reference markers visible in both CBCT and OCT images in order to transfer the plan to the patient. The integrated erbium-doped yttrium aluminum garnet laser was used to mark the surface of the bone by shallow ablation under OCT-based navigation before the surgeon continued the operation. RESULT: The technical setup was feasible, and the laser marking of the border of the IAC was performed with an overall accuracy of 300 µm. The depth of each ablation phase was 300 µm. The marks indicating a safe path supported the surgeon in the surgery. CONCLUSION: The technique investigated in the present study could decrease the surgical risks for the mentioned structures and improve the pace and precision of operation.

Cochlear implantation in children with auditory neuropathy spectrum disorder: A multicenter study on auditory performance and speech production outcomes.

OBJECTIVES: To evaluate the auditory performance and speech production outcome in children with auditory neuropathy spectrum disorder (ANSD). The effect of age on the outcomes of the surgery at the time of implantation was also evaluated. METHODS: Cochlear implantation was performed in 136 children with bilateral severe-to- profound hearing loss due to ANSD, at four tertiary academic centers. The patients were divided into two groups based on the age at the time of implantation; Group I: Children ≤24 months, and Group II: subjects >24 months. The categories of auditory performance (CAP) and speech intelligibility rating (SIR) scores were evaluated after the first and second years of implantation. The differences between the CAP and SIR scores in the two groups were assessed. RESULTS: The median CAP scores improved significantly after the cochlear implantation in all the patients (p value < 0.001). The improvement in the CAP scores during the first year in Group II was greater than Group I (p value: 0.007), but the improvement in CAP scores tended to be significantly higher in patients who were implanted at ≤24 months (p value < 0.001). There was no significant difference between two groups in SIR scores at first-year and second-year follow-ups. The evaluation of the SIR improvement revealed significantly higher values for Group I during the second-year follow-up (p value: 0.003). CONCLUSION: The auditory performance and speech production skills of the children with ANSD improved significantly after cochlear implantation, and this improvement was affected by age at the time of implantation.

Impact of the round window membrane accessibility on hearing preservation in adult cochlear implantation.

This study was conducted to evaluate the effect of the round window membrane accessibility on the residual hearing after cochlear implantation surgery in adults. Moreover, the effects of the other demographics and intra-operative factors on the residual hearing loss have been evaluated. The hearing preservation cochlear implantation surgery was performed on 64 adults with residual hearing thresholds ≤80 dB at 250 and 500 Hz, who had referred to our tertiary academic center. All the patients underwent a standardized surgical approach with the same straight electrode inserted through the round window membrane. The hearing thresholds at 250, 500, and 1000 Hz were compared in pre-operative and 1 month postoperative pure-tone audiograms. The average hearing threshold shifts at these frequencies was used to evaluate the hearing preservation. The effects of the round window accessibility and other factors (including gender, age, side of the surgery, necessity of anterior-inferior drilling of the round window margin and average insertion speed) on hearing threshold shifts were analyzed. The mean low-frequency hearing threshold shift was found to be 17.5 dB for all the patients. The hearing preservation goal (threshold shifts ≤30 dB) was achieved in 58 patients. Among the evaluated parameters, only accessibility of the round window membrane could change the hearing threshold shifts significantly (p = 0.026), and was a predictor for the hearing loss (B coefficient = 7.5, p = 0.006). Incomplete accessibility of the round window membrane may be a predictor for increased hearing threshold shifts in short-term evaluations after cochlear implantation.

Experimental Visualization of Labyrinthine Structure with Optical Coherence Tomography.

INTRODUCTION: Visualization of inner ear structures is a valuable strategy for researchers and clinicians working on hearing pathologies. Optical coherence tomography (OCT) is a high-resolution imaging technology which may be used for the visualization of tissues. In this experimental study we aimed to evaluate inner ear anatomy in well-prepared human labyrinthine bones. MATERIALS AND METHODS: Three fresh human explanted temporal bones were trimmed, chemically decalcified with ethylenediaminetetraacetic acid (EDTA), and mechanically drilled under visual control using OCT in order to reveal the remaining bone shell. After confirming decalcification with a computed tomography (CT) scan, the samples were scanned with OCT in different views. The oval window, round window, and remnant part of internal auditory canal and cochlear turn were investigated. RESULTS: Preparation of the labyrinthine bone and visualization under OCT guidance was successfully performed to a remaining bony layer of 300µm thickness. OCT images of the specimen allowed a detailed view of the intra-cochlear anatomy. CONCLUSION: OCT is applicable in the well-prepared human inner ear and allows visualization of soft tissue parts.

Insertion forces and intracochlear trauma in temporal bone specimens implanted with a straight atraumatic electrode array.

The aim of the study was to evaluate insertion forces during manual insertion of a straight atraumatic electrode in human temporal bones, and post-implantation histologic evaluation of the samples to determine whether violation of intracochlear structures is related to insertion forces. In order to minimize intracochlear trauma and preserve residual hearing during cochlear implantation, knowledge of the insertion forces is necessary. Ten fresh frozen human temporal bones were prepared with canal wall down mastoidectomy. All samples were mounted on a one-axis force sensor. Insertion of a 16-mm straight atraumatic electrode was performed from different angles to induce "traumatic" insertion. Histologic evaluation was performed in order to evaluate intracochlear trauma. In 4 of 10 samples, dislocation of the electrode into scala vestibuli was observed. The mean insertion force for all 10 procedures was 0.003 ± 0.005 N. Insertion forces measured around the site of dislocation to scala vestibuli in 3 of 4 samples were significantly higher than insertion forces at the same location of the cochleae measured in samples without trauma (p < 0.04). Mean force during the whole insertion process of the straight atraumatic electrode is lower than reported by other studies using longer electrodes. Based on our study, insertion forces leading to basilar membrane trauma may be lower than the previously reported direct rupture forces.

The Effect of l-Arginine on Dural Healing After Experimentally Induced Dural Defect in a Rat Model.

BACKGROUND: Incomplete repair of the dura mater may result in numerous complications such as cerebrospinal fluid leakage and meningitis. For this reason, accurate repair of the dura mater is essential. In this study, the effect of systemic and local supplementation of l-arginine on dural healing was evaluated. METHODS: Thirty male Wistar rats were used and divided into control, local, and systemic l-arginine groups, with 10 rats in each. In each group, a 5-mm experimental incision was made at the lumbar segment of the dura mater and cerebrospinal fluid leakage was induced. Each group was divided into 2 subgroups and at the end of the first and sixth weeks, the rats were killed and the damaged segments of the dura were separated, histologically evaluated and the dural healing indicators including cell types, granulation tissue formation, collagen deposit, and vascularization were compared between groups. RESULTS: The systematic supplementation of l-arginine showed a significant effect in dural healing compared with the control group. After the first week, granulation formation increased considerably (P < 0.031), and after 6 weeks, collagen deposition and neovascularization were significantly different compared with the control group (P < 0.030; P < 0.009). In comparison between different groups at the end of the first and sixth weeks, maximum changes in healing indicators were observed in the systemic group and the least variations were related to the control group. CONCLUSIONS: The systemic supplementation of l-arginine may accelerate dural healing by increasing the level of granulation tissue formation, collagen deposition, and vascularization.

Congenital aural atresia surgery: transmastoid approach, complications and outcomes.

Repair of complete congenital aural atresia (CAA) could be a challenging procedure due to complications reported with CAA surgery such as facial nerve palsy, canal stenosis, graft lateralization, sensorineural hearing loss or the difficulty involved in the surgical technique. From 2006 to 2009, we used a one stage-modified transmastoid approach for surgical repair of 33 ears with complete CAA via a non-randomized controlled clinical trial. Some modifications in the technique of mastoidectomy, ossiculoplasty, fascia and skin grafting and meatoplasty have been described. Patients were followed up for 12 months to assess audiometric results and post-operative complications. Changes in air-bone gap and need for revision surgery or hearing aids were assessed at follow-up. There were no cases of facial weakness, dead ear or bony canal stenosis. Hearing success in 2 months follow-up was achieved in 72.7% of all patients. Success rate increased to 92.3% in patients with Jahrsdoefer's scores of 8 and above. Overall success rate decreased to 63.6% at 12 months follow-up. There were no significant difference in Jahrsdoerfer score of patients with successful first surgical attempt and those who needed revision surgery (P value >0.056). Also patients of lower age (less than 5-years-old) did not have more need for revision surgery when compared with older patients (P value >0.36). However, being a syndromic patient did increase the need for revision surgery (P value <0.04). Age was not a predictor of meatal/canal stenosis and patients with lower Jahrsdoerfer scores could also achieve good results.