Unilateral Laser Research Articles

Unilateral laser ventriculocordectomy results in increased arytenoid stability in horses with severe left sided recurrent laryngeal neuropathy.

There is no objective information reporting the effect of unilateral laser ventriculocordectomy (VeC) on arytenoid abduction or stability. To evaluate arytenoid stability and abduction in horses with severe recurrent laryngeal neuropathy (RLN) before and after unilateral laser VeC. Prospective cohort. Eight horses with grade C or D exercising laryngeal function that underwent unilateral laser VeC were included. Exercising endoscopy was performed before and ≥6 weeks after left-sided laser VeC. Arytenoid stability at maximal exercise was calculated by measuring the left-to-right quotient angle ratio (LRQ) of the corniculate processes at the points of maximal arytenoid abduction (expiration) and maximal arytenoid collapse (inspiration). For each horse, means of measurements obtained for four breaths pre- and post-operatively were used for statistical analysis. The difference in LRQ between inspiration and expiration was lower post-operatively (median 0.039; interquartile range [IQR] 0.032-0.047) compared with pre-operatively (median 0.158; IQR 0.083-0.249; p = 0.01) confirming the left arytenoid was more stable following unilateral laser VeC. The degree of improvement was significantly greater for grade D horses compared with grade C horses (p = 0.04). The LRQ measured on maximal abduction was also lower post-operatively (median 0.467; IQR 0.444-0.506) compared with pre-operatively (median 0.578; IQR 0.554-0.655; p = 0.02) indicating the left arytenoid was less abducted following surgery. The sample size was small, no racehorses were included and post-operative assessment was conducted at a variable time after surgery. Unilateral laser VeC in grade C and D RLN-affected horses results in slightly reduced left arytenoid abduction but increased arytenoid stability.

Relationship of Gender With Laser Retinopexy for Retinal Breaks.

To explore the relationship of gender with laser retinopexy for retinal breaks in the Pakistani population. This was a 10-year retrospective observational study conducted at Aga Khan University Hospital, Karachi, Pakistan. All consecutive patients who underwent laser retinopexy between January 2009 and December 2018 for a retinal tear or high-risk retinal degeneration (such as lattice degeneration) were included in this study. Data were collected from patients' files. Index eyes with a history of or treatment for retinal detachment were excluded. A structured pro forma was used to collect information. Descriptive statistics were used to explore the relationship between gender and laser retinopexy. We identified 12,457 patients through the coding system of our hospital who underwent various laser procedures from January 2009 to December 2018. Yttrium aluminium garnet (YAG) laser, laser peripheral iridotomy (PI), and laser trabeculoplasty procedures were all excluded. A total of 3,472 patients' files were reviewed for this study, out of which 958 patients met the inclusion criteria. Males accounted for a higher number (n=515, 53.87%). The mean age was 43.99±15.37 years. For exploratory analysis, participants were divided into five age groups: <30 years (24.16%); 31-40 years (16.59%); 41-50 years (19.45%); 51-60 years (26.40%); and >60 years (13.49%). Bilateral laser retinopexy was performed in 48.12% of patients; 24.79% and 27.13% of patients underwent unilateral laser retinopexy for the right and left eyes, respectively. In our cohort study, laser retinopexy was more commonly performed in men than in women. The ratio was not significantly different from the prevalence of retinal tears and retinal detachment in the general population, which has a slightly higher male preponderance. We did not find evidence of significant gender bias among patients who underwent laser retinopexy in our study.

Analysis of the Effectiveness of Arytenoidectomy and Posterior Cordectomy with the Use of CFD Airflow Measurements in Patients with BVFP: A Retrospective Study.

Bilateral vocal fold paralysis (BVFP) is a rare larynx disease manifested by dyspnea, which often requires surgical treatment. The aim of the study is to determine the effectiveness of unilateral arytenoidectomy with posterior cordectomy in the treatment of BVFP using the computational fluid dynamics (CFD) method. This study included 33 patients with BVFP who underwent unilateral laser arytenoidectomy with posterior cordectomy. Glottis area measurements and spirometry, as well as a self-assessment of respiratory efficiency were performed before the surgery and after the recovery period. Using the CFD method, computer models of the glottis were made. Then, changes in air pressure gradient and maximum air velocity at the level of glottis were calculated, and local fields of pressure and air velocities were obtained. The values of glottal surface area (S), spirometry parameters (forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and peak expiratory flow (PEF)), inlet air velocity at the glottal level as well as patients self-assessment of respiratory efficiency turned out to be significantly higher after the operation. The values of maximum velocity at the glottal level, pressure gradient at the glottal level turned out to be significantly lower after the surgery. We observed that the greater the increase in glottal surface area, the greater the decrease in self-assessment scales (visual analogue scale (VAS) and Medical Research Council (MRC)). Increased levels of spirometry parameters after the surgery correlated with smaller decrease of PEF-dependent pressure gradient at the glottal level (PEFΔP CFD). Unilateral laser arytenoidectomy with posterior cordectomy is an effective method for the treatment of BVFP. CFD is a useful tool to determine and visualize the effectiveness of surgical treatment in BVFP.

Refractive outcomes following unilateral laser treatment for type 1 retinopathy of prematurity

To compare refractive outcomes of infants with type 1 retinopathy of prematurity (ROP) in whom one eye was treated with laser and the fellow eye spontaneously regressed. The medical records of infants who underwent IVB and laser treatment for type 1 ROP or aggressive posterior-ROP between January 2016 and December 2019 were retrospectively evaluated. Infants in whom ROP in the fellow eye regressed and for whom refractive data was available in the record were included in the study. Refractive outcomes of unilaterally treated infants were assessed. A total of 283 cases were reviewed: of these, 17 experienced spontaneous regression in the fellow eye and were included. All unilateral laser-treated eyes had type 1 ROP in zone Ⅱ. The median age at treatment was 40 weeks' postmenstrual age (IQR, 39-41). The mean spherical equivalent at the last examination was 2.1 ± 2.5 D in treated eyes and 2.50±1.4 D in nontreated eyes, at a mean age of 25.0 ± 9.1 months (P = 0.378). Ofthe 7 infants who underwent fluorescein angiography, the median of the ratio of the length of the temporal retinal vascularization to the optic disk-to-fovea distance was 3.71 (3.22-3.79) in treated and 4.28 (3.90-4.49) in untreated eyes, at a median age of 18 months (P = 0.018). In laser-treated eyes with peripheral zone Ⅱ ROP and with advanced treatment age, wedidnot observe a significant myopic change compared to the fellow untreated eye.

Research on microstructure evolution and tensile characteristics of Ti6Al4V double lap-fillet joints fabricated by dual laser-beam bilateral synchronous welding

Employing prefabricated “boss” on the substrate to replace wire feeding, an attempt is made to explore the non-filler welding process of Ti6Al4V double lap-fillet welded joints with the technology of dual laser-beam bilateral synchronous welding (DLBSW). The weld quality is evaluated in terms of bead geometry, microstructural morphology and mechanical property. An optimal range of welding speed (1.3 m/min) with constant unilateral laser power of 950 W is identified to achieve satisfactory weldments with no underfill defect and acceptable porosity. Phase transformation and microstructural evolution occurring through thermal history in different regions of the welded joint are clarified. The average length of α'-martensite in the weld seam (WS) decreases significantly as welding speed increases. A connection between dimensional variation of α'-martensite and tensile strength is developed, and the fracture mechanism of the lap-fillet joint is discussed. The existence of fine α'-martensites helps to attain high-performance joints with strength comparable to the base metal (BM). The fracture position of tensile specimens is located in the region near the weld toe where stress concentration occurs. Fractography analysis indicates that the failure of weldments is in ductile mode with the feature of a great number of dimples.

Case Series: Unilateral Amygdala Ablation Ameliorates Post-Traumatic Stress Disorder Symptoms and Biomarkers

Background Post-traumatic stress disorder is a severe psychobiological disorder associated with hyperactivity of the amygdala, particularly on the right side. Highly selective laser ablation of the amygdalohippocampal complex is an effective neurosurgical treatment for medically refractory medial temporal lobe epilepsy that minimizes neurocognitive deficits relative to traditional open surgery. Objective To examine the impact of amygdalohippocampotomy upon symptoms and biomarkers of post-traumatic stress disorder. Methods Two patients with well-documented chronic post-traumatic stress disorder who subsequently developed late-onset epilepsy underwent unilateral laser amygdalohippocampotomy. Prospective clinical and neuropsychological measurements were collected in patient 1. Additional prospective measurements of symptoms and biomarkers were collected pre- and post-surgery in patient 2. Results After laser ablation targeting the nondominant (right) amygdala, both patients experienced not only reduced seizures, but also profoundly abated post-traumatic stress symptoms. Prospective evaluation of biomarkers in patient 2 showed robust improvements in hyperarousal symptoms, fear potentiation of the startle reflex, brain functional magnetic resonance imaging responses to fear-inducing stimuli, and emotional declarative memory. Conclusion These observations support the emerging hypothesis that the right amygdala particularly perpetuates the signs and symptoms of post-traumatic stress disorder and suggests that focal unilateral amydalohippocampotomy can provide therapeutic benefit.

The Reliability and Validity of the Measurements in Unilateral Cleft Lip and Palate Laser Scanned 3D Dental Casts

Objective: To evaluate the reliability and validity of the Next Engine 3D Laser scanner. Material and Methods: A total of 30 dental casts of unilateral cleft lip and palate (UCLP) children with 90 linear variables were measured using digital caliper while the laser-scanned 3D dental casts (LS3DM) were measured using Mimics Software. All scanned data coordinates (in x, y, z) were transferred into Mimics software in STL format to be measured. All the variables were measured using a computer mouse accurate to 0.5 mm. The intra-class correlation coefficient (ICC) was used to evaluate the intra- and inter-examiner reliabilities and also for the validity of two methods. Results: Intra-examiner reliabilities of digital caliper and LS3DM were found excellent (ICC 0.916-0.995) and inter-examiner reliabilities of LS3DM were good to excellent (ICC 0.816-0.990). The validity of LS3DM measurements was confirmed based on the ICC values were in the range of 0.913-0.996. The overall time frame for conducting measurements was shorter using a laser-scanned model (10 min.) than using a digital caliper (5 hours). Conclusion: The LS3DM is a valid reliable tool for future high impact research in our institution.

Overground endoscopic findings and respiratory sound analysis in horses with recurrent laryngeal neuropathy after unilateral laser ventriculocordectomy

Unilateral ventriculocordectomy (VeC) is frequently performed, yet objective studies in horses with naturally occurring recurrent laryngeal neuropathy (RLN) are few. To evaluate respiratory noise and exercising overground endoscopy in horses with grade B and C laryngeal function, before and after unilateral laser VeC. Prospective study in clinically affected client-owned horses. Exercising endoscopy was performed and concurrent respiratory noise was recorded. A left-sided laser VeC was performed under standing sedation. Owners were asked to present the horse for re-examination 6-8weeks post-operatively when exercising endoscopy and sound recordings were repeated. Exercising endoscopic findings were recorded, including the degree of arytenoid stability. Quantitative measurement of left-to-right quotient angle ratio (LRQ) and rima glottidis area ratio (RGA) were performed pre- and post-operatively. Sound analysis was performed, and measurements of the energy change in F1, F2 and F3 formants between pre- and post-operative recordings were made and statistically analysed. Three grade B and seven grade C horses were included; 6/7grade C horses preoperatively had bilateral vocal fold collapse (VFC) and 5/7 had mild right-sided medial deviation of the ary-epiglottic fold (MDAF). Right VFC and MDAF was still present in these horses post-operatively; grade B horses had no other endoscopic dynamic abnormalities post-operatively. Sound analysis showed significant reduction in energy in formant F2 (P=0.05) after surgery. The study sample size was small and multiple dynamic abnormalities made sound analysis challenging. RLN-affected horses have reduction in sound levels in F2 after unilateral laser VeC. Continuing noise may be caused by other ongoing forms of dynamic obstruction in grade C horses. Unilateral VeC is useful for grade B horses based on endoscopic images. In grade C horses, bilateral VeC, right ary-epiglottic fold resection ± laryngoplasty might be a better option than unilateral VeC alone. The Summary is available in Portuguese - see Supporting Information.

Transduction Patterns of Adeno-associated Viral Vectors in a Laser-Induced Choroidal Neovascularization Mouse Model

Adeno-associated virus (AAV) vector is a promising platform technology for ocular gene therapy. Recently clinical successes to treat choroidal neovascularization (CNV) in wet type age-related macular degeneration have been reported. However, because pathologic conditions of the retina may alter the tropism of viral vectors, it is necessary to evaluate the transduction efficiency of different serotypes of AAV vectors in the retinas with CNVs. Here, we show the patterns and efficacy of transduction of AAV2, -5, and -8 vectors in a laser-induced CNV mouse model. C57BL/6J mice were subjected to unilateral laser photocoagulation on the right eye to induce CNV 5 days prior to intravitreal injection of AAV2, -5, and -8 capsids expressing EGFP. Transduction was increased around CNV lesions for all AAV capsid types, and AAV2 resulted in the highest transduction efficiency. In the absence of CNV, the AAV2 vector transduced ganglion and inner nuclear layer (INL) cells, and AAV5 and AAV8 transduced only a small proportion of cells in the retinal ganglion cell layer. CNV increased AAV2 vector expression throughout the retina and in and around CNVs; the transduced cells included retinal ganglion cells, Müller cells, cells from the INL and outer nuclear layer (ONL), photoreceptors, and retinal pigment epithelium (RPE) cells. Inflammatory cells and endothelial cells in CNVs were also transduced by AAV2. AAV5 and AAV8 were transduced in retinal ganglion, Müller, INL, ONL, and RPE cells in a localized pattern, and only endothelial cells at the surface of CNV lesions showed EGFP expression. Taken together, CNV formation resulted in enhanced transduction of AAV2, -5, and -8, and AAV2 exhibited the highest transduction efficiency in cells in CNV lesions.

Overground Endoscopic Findings and Respiratory Sound Analysis in Horses With Recurrent Laryngeal Neuropathy After Unilateral Laser Ventriculocordectomy

Overground Endoscopic Findings and Respiratory Sound Analysis in Horses With Recurrent Laryngeal Neuropathy After Unilateral Laser Ventriculocordectomy

Assessment of Low-Level Laser Therapy Effects After Extraction of Impacted Lower Third Molar Surgery.

Introduction: The aim of this study was to assess the effect of low-level laser therapy (LLLT) on pain, swelling and maximum mouth opening in patients undergoing third molar surgery. Methods: A prospective, randomized double-blind study was undertaken on 44 patients at the Dental School, Ahvaz Jundishapur University of Medical Sciences, in 2015. A low-level laser was randomly applied on one of the two sides after surgery of 15 patients. The experimental side received 18 J/cm2 of energy density, wavelength of 980 nm, and output power of 1.8 W. On the control side, a hand-piece was applied intra-orally, but laser was not activated. In addition, in order to evaluate trismus, 13 patients were treated by unilateral laser therapy and 16 patients did not receive laser therapy at all. The laser was administered intraorally on two points of vestibular and lingual sides at 1 cm from the surgery site, and extraorally at the emergence of the masseter muscle, immediately after surgery, and repeated 24 hours later. The pain, swelling and maximum mouth opening (MMO) were compared between the two groups at 24 hours and a week after surgery. Results: The mean score of pain 24 hours after surgery in the laser therapy group (2.3 ± 3.5) was significantly lower than the mean score of pain in the drug therapy (4.19 ± 3.09) (P = 0.036). Moreover, the mean score of pain at one week after surgery in the laser therapy group (0.13 ± 2.33) was significantly lower than the drug therapy group (1.43 ± 2.45) (P = 0.046). The amount of swelling according to different measurements did not significantly differ between the two groups neither at 24 hours nor at 1 week after surgery. Conclusion: Our findings showed that LLLT was useful in reducing pain and could slightly reduce swelling compared to drug therapy in impacted third molar surgery.

Split face evaluation of long-pulsed non-ablative 1,064 nm Nd:YAG laser for treatment of direct browplasty scars.

To investigate 1,064 nm long-pulse Nd:YAG laser for postoperative treatment of direct browplasty scars. Nine patients who underwent direct browplasty were enrolled in this prospective study. Subjects were randomized to unilateral laser treatment at 2-week intervals for six total treatments, with the contralateral scar used as a control. Prior to each treatment, subjects rated treated and control scars on overall cosmesis. Post-treatment, subjects rated each for erythema, swelling, discomfort, and perceived hair loss. Finally, examiners masked to treatment side were asked to judge side-by-side photographs of first and final visits for improvement and side effects. Subjects rated the overall appearance of the treated scar significantly higher at the time of treatment number 5 (mean score 5.13 ± 2.03, P = 0.008) and treatment number 6 (6.25 ± 1.98, P = 0.005) compared to treatment 1 (3.75 ± 2.12); by contrast, they failed to rate the control scar more highly. On masked examination of photographs, the treated scar was selected as most improved 50.0 ± 12.5% of the time. Both subjects and graders reported side effects as transient and mild to moderate (mean score 1-4), with no reports of hair loss from either subjects or observers. The 1,064 nm Nd:YAG laser provided significant improvement in scar cosmesis after direct browplasty, as rated by subject self-report, but not by masked observers, and appears to be a useful tool for increasing satisfaction among those dissatisfied with direct browplasty scars. Side effects-including erythema, edema, and discomfort-were transient and universally rated as mild to moderate. Lasers Surg. Med. 48:742-747, 2016. © 2016 Wiley Periodicals, Inc.

Simultaneous bilateral laser therapy accelerates recovery after noise-induced hearing loss in a rat model.

Noise-induced hearing loss is a common type of hearing loss. The effects of laser therapy have been investigated from various perspectives, including in wound healing, inflammation reduction, and nerve regeneration, as well as in hearing research. A promising feature of the laser is its capability to penetrate soft tissue; depending on the wavelength, laser energy can penetrate into the deepest part of the body without damaging non-target soft tissues. Based on this idea, we developed bilateral transtympanic laser therapy, which uses simultaneous laser irradiation in both ears, and evaluated the effects of bilateral laser therapy on cochlear damage caused by noise overexposure. Thus, the purpose of this research was to assess the benefits of simultaneous bilateral laser therapy compared with unilateral laser therapy and a control. Eighteen Sprague-Dawley rats were exposed to narrow-band noise at 115 dB SPL for 6 h. Multiple auditory brainstem responses were measured after each laser irradiation, and cochlear hair cells were counted after the 15th such irradiation. The penetration depth of the 808 nm laser was also measured after sacrifice. Approximately 5% of the laser energy reached the contralateral cochlea. Both bilateral and unilateral laser therapy decreased the hearing threshold after noise overstimulation in the rat model. The bilateral laser therapy group showed faster functional recovery at all tested frequencies compared with the unilateral laser therapy group. However, there was no difference in the endpoint ABR results or final hair cell survival, which was analyzed histologically.

Utilization of laryngeal ultrasound and laryngoscopy for the diagnosis and management of bilateral vocal fold paralysis

Abstract Management of a severely compromised airway because of bilateral paralysis of the vocal cords represents a significant challenge. The aim of this study is to establish the validity and accuracy of ultrasonography in the evaluation of CO 2 laser surgery using optical endoscopy as the gold-standard technique. A thorough ultrasonographic examination of the vocal cords during different phases of respiration and phonation, both pre-CO 2 and post-CO 2 laser surgery, was performed. Endoscopic partial transverse cordectomy, using a CO 2 laser, was the operation of choice in the management of bilateral vocal cord paralysis. Thirty-six patients were included in this study; a control group of 125 normal volunteers was also included for standardization of the ultrasonographic technique. Patients with bilateral immobility of the vocal cords (36) in the adduction position were subjected to a CO 2 laser. Endoscopic partial transverse cordectomy was performed. Twenty patients required unilateral laser surgery because the anterior angle was 12° or greater by ultrasound measurement. Postoperative follow-up of the anterior angle increased from 14° to 26°, whereas 16 patients (45%) required bilateral laser surgery as the anterior angle was less than 12° on ultrasound. Postoperatively, the anterior angle increased from 16° to 26°. Ultrasonography is the modality of choice in the evaluation of patients with bilateral vocal cord paralysis quantitatively and dynamically. These might improve the functional results of one-step CO 2 laser surgery. 4.

Analysis and simulation of entirely saturated unilateral laser spot tails in BCCD.

A new phenomenon involving the entire saturation of unilateral tails of buried channel charge-coupled devices (BCCDs) under laser radiation is observed in this study. A physical model related to this phenomenon is constructed based on the assumption that the charge transfer inefficiency of BCCD is a jump function of signal charge quantity. The profile of a spot tail under laser radiation is simulated using this self-developed model. The simulation results are compared with experimental findings to validate this model.

Time-Dependent Changes of Cell Proliferation After Laser Photocoagulation in Mouse Chorioretinal Tissue.

This study investigated the time course of cell proliferation after laser photocoagulation and analyzed the cell types of proliferating cells. C57BL/6J mice received unilateral laser photocoagulation. Intraperitoneal bromodeoxyuridine (BrdU) injection was performed, and mice were divided into two groups according to the injection paradigm: group 1 with continuous injection and group 2 with periodic injection. Each group was again divided into four subgroups according to injection period: 0 to 3 days (n = 11), 0 to 7 days (n = 14), 0 to 14 days (n = 6), and 0 to 28 days (n = 6) after laser photocoagulation for group 1; and 0 to 3 days (n = 11), 4 to 7 days (n = 6), 8 to 14 days (n = 6), and 15 to 28 days (n = 6) after laser photocoagulation for group 2. The eyes were examined with immunohistochemistry using anti-BrdU antibody and other various antibodies for identification of proliferating cells. Manual cell counting and flow cytometry were performed for quantification. In group 1, the number of BrdU+ cells showed marked increase during the first 3 days of laser lesioning, reaching its maximum after 7 days (P < 0.05). Group 2 also demonstrated peak proliferation during the first 3 days, but a significantly reduced number of BrdU+ cells were detected during 4 to 7 days, 8 to 14 days, and 15 to 28 days of laser treatment (P < 0.05). BrdU+ cells colocalized with CD11b, F4/80, iba1, RPE65, CD31, and glial fibrillary acidic protein (GFAP) labeling, and CD11b+, F4/80+, and iba1+ cells constituted the main fraction of BrdU+ cells. Laser photocoagulation induced cell proliferation mostly during the first 3 days, and many proliferating cells were identified as inflammatory cells, RPE cells, endothelial cells, and Müller cells.

Longitudinal alterations in the dynamic autoregulation of optic nerve head blood flow revealed in experimental glaucoma.

To use a novel dynamic autoregulation analysis (dAR) to test the hypothesis that the optic nerve head (ONH) blood flow (BF) autoregulation is disrupted during early stages of experimental glaucoma (EG) in nonhuman primates. Retinal nerve fiber layer thickness (RNFLT, assessed by optical coherence tomography) and ONH BF (assessed by laser speckle imaging technique) were measured biweekly before and after unilateral laser treatment to the trabecular meshwork. Each nonhuman primate was followed until reaching either an early stage of damage (RNFLT loss < 20%, n = 6) or moderate to advanced stages of damage (RNFLT loss > 20%, n = 9). At each test, dAR was assessed by characterizing ONH BF changes during the first minute of rapid manometrical intraocular pressure (IOP) elevation from 10 to 40 mm Hg. The dAR analysis extracted the following parameters: baseline BF, average BF 10 seconds before IOP elevation; BFΔmax, maximum BF change from baseline BF; Tr, time from baseline BF to the BFΔmax; Kr, average descending BF rate. Mean postlaser IOP was 20.2 ± 5.9 and 12.3 ± 2.6 mm Hg in EG and control eyes, respectively (P < 0.0001). Compared with prelaser values, baseline BF was higher in early EG, but lower in moderate to advanced EG (P = 0.01). Tr was increased and Kr was reduced in both stages (P < 0.01). BFΔmax was smaller in the early EG (P = 0.05) and remained low in the moderate to advanced EG (P = 0.15). No changes in the parameters were observed in control eyes. Chronic IOP elevation causes ONH autoregulation dysfunction in the early stage of EG, characterized by a disrupted BF response and delayed Tr, revealed by dAR analysis.

Laser Photocoagulation Enhances Adeno-Associated Viral Vector Transduction of Mouse Retina

Laser photocoagulation is a well-established treatment modality for retinal disease. Discrete laser burns can be placed anywhere in the retina, singly or multiply, and the burn intensity is controllable. This study investigates the effect of prior laser photocoagulation on the retinal transduction properties of intravitreally administered adeno-associated viral (AAV) vectors. C57BL/6J mice were subjected to unilateral laser photocoagulation 48 hr before bilateral intravitreal injection of self-complementary cytomegaloviral enhanced green fluorescent protein (EGFP) vectors packaged in AAV type 2, 5, and 8 capsids. The eyes were enucleated 4 weeks after injection and examined by histochemistry and quantitative image analysis. Laser pretreatment resulted in substantially increased localized transduction around the burn site for all AAV capsid types. Without laser pretreatment, the vectors transduced only ganglion cells (AAV2) or sporadic cells around the optic nerve head (AAV5 and AAV8). Laser pretreatment increased AAV2 vector expression throughout the entire retina and focally at the burn site. Transduced cells at the burn site included retinal pigment epithelium (RPE), photoreceptors, Müller cells, inner nuclear layer cells, and retinal ganglion cells. The AAV5 vector showed increased RPE transduction at the burn site only. The AAV8 vector showed augmented expression in RPE, photoreceptors, and Müller cells around the burn site. Migrating RPE cells, present in the neural retina near the burn site, were also transduced by all three capsid types as evidenced by colocalization of EGFP and cytokeratin. Laser photocoagulation can be used to precisely direct AAV vector transduction to discrete locations in the retina. A combination of laser and AAV-mediated gene expression may allow the development of improved therapies for diabetic retinopathy, branch and central vein occlusion, and age-related macular degeneration.

Spinal Projection Neurons Control Turning Behaviors in Zebrafish

SummaryDiscrete populations of brainstem spinal projection neurons (SPNs) have been shown to exhibit behavior-specific responses during locomotion [1–9], suggesting that separate descending pathways, each dedicated to a specific behavior, control locomotion. In an alternative model, a large variety of motor outputs could be generated from different combinations of a small number of basic motor pathways. We examined this possibility by studying the precise role of ventromedially located hindbrain SPNs (vSPNs) in generating turning behaviors. We found that unilateral laser ablation of vSPNs reduces the tail deflection and cycle period specifically during the first undulation cycle of a swim bout, whereas later tail movements are unaffected. This holds true during phototaxic [10], optomotor [11], dark-flash-induced [12], and spontaneous turns [13], suggesting a universal role of these neurons in controlling turning behaviors. Importantly, we found that the ablation not only abolishes turns but also results in a dramatic increase in the number of forward swims, suggesting that these neurons transform forward swims into turns by introducing turning kinematics into a basic motor pattern of symmetric tail undulations. Finally, we show that vSPN activity is direction specific and graded by turning angle. Together, these results provide a clear example of how a specific motor pattern can be transformed into different behavioral events by the graded activation of a small set of SPNs.

Voice quality after laser cordectomy and vertical hemilaryngectomy

IntroductionVarious surgical techniques have been adopted for management of glottic cancer with the aim of eradicating the disease and preserving the voice character. AimThe aim of the study was to determine the voice quality for patient after various surgical interventions for treatment of cancer larynx, and to evaluate the effect of postoperative voice therapy. Subjects20 patients were subjected to surgical intervention for management of glottic cancer (seven had unilateral laser cordectomy-group A, and five had bilateral laser cordectomy-group B and eight had vertical hemilaryngectomy-group C). Thirteen age matched males were randomly selected for obtaining normal computer voice function parameters as the control group-group D. MethodologyThe four groups were subjected to protocol of voice evaluation postoperatively. Patients were re-evaluated two months later and a comparison of voice outcome for patients receiving voice therapy and those who did not was conducted. ConclusionMost acoustic and aerodynamic parameters are significant different between patients from control. Subharmonics parameters (NSH and DSH) and degree of voice breaks (DVB) in addition to phonatory resistance specifically differentiate the voice of laser cordectomized from that of vertical hemilaryngectomized patient, this may reflect occurrence of vocal fry related to supraglottic phonation. Improvement was recorded by all patients receiving voice therapy. Unilateral laser cordectomy gave better phonatory outcome due to less extension of surgical resection and development of glottic phonation. Bilateral laser cordectomy gave relatively worse prognosis highlighting the advantage of the experience of surgeon in creation of pseudoglottis in improving phonatory outcome in vertical hemilaryngectomy over extensive resection of bilaterally cordectomized patients.