Publications by authors named "Sansar Sharma"

40 Publications

Differential Distribution of RBPMS in Pig, Rat, and Human Retina after Damage.

Int J Mol Sci 2020 Dec 7;21(23). Epub 2020 Dec 7.

Department of Cell Biology and Histology, Experimental Ophthalmo-Biology Group (GOBE), University of the Basque Country UPV/EHU, 48940 Leioa, Vizcaya, Spain.

RNA binding protein with multiple splicing (RBPMS) is expressed exclusively in retinal ganglion cells (RGCs) in the retina and can label all RGCs in normal retinas of mice, rats, guinea pigs, rabbits, cats, and monkeys, but its function in these cells is not known. As a result of the limited knowledge regarding RBPMS, we analyzed the expression of RBPMS in the retina of different mammalian species (humans, pigs, and rats), in various stages of development (neonatal and adult) and with different levels of injury (control, hypoxia, and organotypic culture or explants). In control conditions, RBPMS was localized in the RGCs somas in the ganglion cell layer, whereas in hypoxic conditions, it was localized in the RGCs dendrites in the inner plexiform layer. Such differential distributions of RBPMS occurred in all analyzed species, and in adult and neonatal retinas. Furthermore, we demonstrate RBPMS localization in the degenerating RGCs axons in the nerve fiber layer of retinal explants. This is the first evidence regarding the possible transport of RBPMS in response to physiological damage in a mammalian retina. Therefore, RBPMS should be further investigated in relation to its role in axonal and dendritic degeneration.
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http://dx.doi.org/10.3390/ijms21239330DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7729751PMC
December 2020

A Balancing Act.

Authors:
Sansar Sharma

J Pediatr Ophthalmol Strabismus 2018 Jul;55(4):216-217

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http://dx.doi.org/10.3928/01913913-20180530-01DOI Listing
July 2018

ACUTE RETINAL NECROSIS AND CONTRALATERAL CUTANEOUS ERUPTION AFTER THE SHINGLES VACCINE.

Retin Cases Brief Rep 2021 Jan;15(1):43-44

Department of Ophthalmology, New York Medical College.

Purpose: To the best of our knowledge, we present a rare case report describing an occurrence of acute retinal necrosis in an otherwise healthy individual who received the shingles vaccine.

Methods: Observational case report.

Patient: A 63-year-old healthy and immunocompetent white man presented with change of vision in the left eye after blunt trauma. A diagnosis of corneal abrasion was made. During follow-up, a detailed history discovered a progressive deterioration in vision over the past few weeks. Three months before presentation, he had received the shingles vaccine (Zostavax); 1 month before presentation, he reported an episode of varicella skin eruption on the face.

Results: On examination, the patient was found to have acute retinal necrosis with white satellite lesions in the fundus of the left eye. An anterior chamber paracentesis and polymerase chain reaction confirmed the diagnosis of varicella-zoster virus.

Conclusion: Varicella-zoster virus reactivation after shingles vaccination may predispose both immunocompetent and immunocompromised individuals to herpes-zoster ophthalmicus, leading to acute retinal necrosis.
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http://dx.doi.org/10.1097/ICB.0000000000000729DOI Listing
January 2021

Ocular Hypertension/Glaucoma in Minipigs: Episcleral Veins Cauterization and Microbead Occlusion Methods.

Methods Mol Biol 2018 ;1695:41-48

Department of Anatomy and Cell Biology, New York Medical College, Valhalla, NY, USA.

Two methods to induce elevation of the intraocular pressure (experimental glaucoma) are described in the present chapter. The first method is based on increasing the post-trabecular resistance to aqueous outflow by cauterizing the episcleral veins (EVC). This method allows the observation of ultrastructural changes in the trabecular meshwork (TM) without interfering with any structure within the eye such as TM, ciliary body, and/or the Retina. The second method is the multiple injection of microbeads into the anterior chamber, as a pre and intra-trabecular method that induce secondary effects on the TM cells. Both methods lead to an increase in IOP.
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http://dx.doi.org/10.1007/978-1-4939-7407-8_4DOI Listing
July 2018

Chronic Uveitis Following Neodymium-Doped Yttrium Aluminum Garnet Laser Peripheral Iridotomy.

J Glaucoma 2017 Oct;26(10):e229-e231

Departments of *Ophthalmology †Ophthalmology and Neuroscience, New York Medical College, Valhalla, NY.

Purpose: Assessment of a chronic uveitis entity in nonuveitic patients following neodymium-doped yttrium aluminum garnet (Nd:YAG) laser peripheral iridotomy.

Methods: A 7-year retrospective observational case series of 5 patients that developed chronic uveitis following a Nd:YAG laser peripheral iridotomy treatment.

Results: Five eyes of 5 nonconsecutive patients had developed chronic anterior uveitis lasting >12 weeks. Four patients were female, with a mean age of 60.3 years (range, 48 to 83 y), and a mean follow-up duration of 8 months after initiation of treatment.

Conclusions: Chronic anterior uveitis should be addressed as a possible risk in patients undergoing Nd:YAG laser iridotomies. A larger prospective study would be necessary in establishing and exploring the association between these 2 entities.
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http://dx.doi.org/10.1097/IJG.0000000000000736DOI Listing
October 2017

Influence of Netrin-1 on reinnervation of laryngeal muscles following recurrent laryngeal nerve injury.

Neurosci Lett 2017 Jul 17;653:244-249. Epub 2017 May 17.

Department of Otolaryngology - Head and Neck Surgery, Columbia University Medical Center, New York, NY, USA. Electronic address:

Following recurrent laryngeal nerve (RLN) injury, recovery results in poor functional restitution of the paralyzed vocal fold. Netrin-1 has been found to be upregulated in the rat posterior cricoarytenoid muscle (PCA) during nerve regeneration. We evaluated the effect of ectopic Netrin-1 in the PCA during RLN reinnervation. The right RLN was transected and Netrin-1 was injected into the PCA (2.5, 5, 10, 15, 20μg/ml). At 7 days post injury fluorescent retrograde tracer was injected into the PCA and Thyroarytenoid (TA) muscles. At 9 days tissues were harvested. Immunostaining showed reinnervation patterns in the laryngeal muscles and labelled motoneurons in the nucleus ambiguus. Lower concentrations of Netrin-1 (2.5 and 5μg/ml) showed no significant changes in laryngeal muscles reinnervation. Higher concentrations of Netrin-1 significantly reduced motor end plate innervation. The most effective dose was 10μg/ml showing reduced number of innervated motor endplates in the PCA. The somatotopic organization of the nucleus ambiguus was altered in all concentrations of Netrin-1 injection. These findings indicate that injection of Netrin-1 into the PCA changes the reinnervation pattern of the RLN.
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http://dx.doi.org/10.1016/j.neulet.2017.05.033DOI Listing
July 2017

Muscle specific nucleus ambiguus neurons isolation and culturing.

J Neurosci Methods 2016 11 27;273:33-39. Epub 2016 Jul 27.

Department of Cell Biology and Anatomy, New York Medical College, Basic Sciences Building, 15 Dana Road, Valhalla, New York 10595, United States.

Background: Peripheral nerve injury leads to a regenerative state. However, the reinnervation process is highly non-selective. Growing axons are often misrouted and establish aberrant synapsis to abductor or adductor muscles. Determining the complex properties of abductor and adductor motoneurons in a neuron culture, may lay the groundwork for future studies on axon guidance, leading to a clinical treatment for a selective reinnervation.

New Method: In the present study we develop a neuron culture protocol to isolate recurrent laryngeal nerve abductor and adductor motoneurons in order to study their unique properties. Comparison with existing methods the best period to perform the present protocol for postnatal rat cranial motoneurons isolation was determined. In addition, the method allows identification of specific motoneurons from other primary motoneurons and interneurons within brainstem.

Conclusion: The present protocol will allow investigators to perform targeted and novel studies of the mechanisms of peripheral nerve regeneration.
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http://dx.doi.org/10.1016/j.jneumeth.2016.07.014DOI Listing
November 2016

Changes in neurotrophic factors of adult rat laryngeal muscles during nerve regeneration.

Neuroscience 2016 10 12;333:44-53. Epub 2016 Jul 12.

Department of Otolaryngology, New York Eye and Ear Infirmary of Mount Sinai, 310E, 14th Street, 6th Floor, New York Eye and Ear Infirmary, New York, NY 10003, United States.

Injury to the recurrent laryngeal nerve (RLN) leads to the loss of ipsilateral laryngeal fold movement, with dysphonia, and occasionally dysphagia. Functional movement of the vocal folds is never restored due to misrouting of regenerating axons to agonist and antagonist laryngeal muscles. Changes of neurotrophic factor expression within denervated muscles occur after nerve injury and may influence nerve regeneration, axon guidance and muscle reinnervation. This study investigates the expression of certain neurotrophic factors in the laryngeal muscles during the course of axonal regeneration using RT-PCR. The timing of neurotrophic factor expression was correlated to the reinnervation of the laryngeal muscles by motor axons. Nerve Growth Factor (NGF), Brain-Derived Neurotrophic Factor (BDNF) and Netrin-1 (NTN-1) increased their expression levels in laryngeal muscles after nerve section and during regeneration of RLN. The upregulation of trophic factors returned to control levels following regeneration of RLN. The expression levels of the neurotrophic factors were correlated with the innervation of regenerating axons into the denervated muscles. The results suggest that certain neurotrophic factor expression is strongly correlated to the reinnervation pattern of the regenerating RLN. These factors may be involved in guidance and neuromuscular junction formation during nerve regeneration. In the future, their manipulation may enhance the selective reinnervation of the larynx.
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http://dx.doi.org/10.1016/j.neuroscience.2016.07.004DOI Listing
October 2016

Forgotten intrauterine contraceptive device - A threat to total hip prosthesis: A case report with review of the literature.

J Clin Orthop Trauma 2016 Apr-Jun;7(2):130-3. Epub 2015 Nov 27.

Director and Professor, Department of Orthopedics, SHKM Government Medical College, Mewat, Haryana 122107, India.

Primary total hip replacement has become a routine procedure these days. With improvement in surgical techniques and implant designs, the survival rate of prosthesis has increased significantly but unfortunately, prosthetic infections though uncommon continue to be a threatening complication. We present a detailed review of the literature along with a case report of infected total hip prosthesis in a 36-year-old female who had been operated 6 years back. The causative organism was found to be Actinomyces israelii which was related to an infected intrauterine device used for contraception that had been forgotten after being implanted 8 years earlier.
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http://dx.doi.org/10.1016/j.jcot.2015.10.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4857142PMC
May 2016

Blockade of glial-derived neurotrophic factor in laryngeal muscles promotes appropriate reinnervation.

Laryngoscope 2016 10 5;126(10):E337-42. Epub 2016 Apr 5.

Department of Otolaryngology, New York Eye and Ear Infirmary of Mount Sinai, New York, New York, U.S.A.

Objectives/hypothesis: Synkinetic reinnervation of the laryngeal muscles is one of the causes of the poor functional recovery after a recurrent laryngeal nerve (RLN) injury. Glial-derived neurotrophic factor (GDNF) is elevated in rat laryngeal muscles during RLN reinnervation. The specific aim of this investigation was to evaluate the effect of anti-GDNF on RLN reinnervation.

Methods: Anti-GDNF antibody was injected into the posterior cricoarytenoid (PCA) 3 days following RLN transection and anastomosis. Larynges were harvested at 7, 14, 28, 56, and 112 days post injury (DPI). Prior to sacrifice, the vocal fold mobility was assessed. Immunostaining to identify neuromuscular junctions was used to evaluate the extent of axonal reinnervation of the PCA, lateral thyroarytenoid (LTA), and medial thyroarytenoid (MTA).

Results: After anti-GDNF injection into PCA, RLN reinnervation in all muscles was altered when compared to the controls. PCA innervation was delayed. At 7 DPI, only a few axons made synapses in the PCA. In contrast, axons prematurely innervated the LTA and MTA when compared to controls. Innervation was similar to controls at 56 and 112 DPI. Vocal fold motion was enhanced in 10 of 24 animals studied.

Conclusions: After injection of anti-GDNF into the PCA, early arriving axons bypass the PCA and enter the LTA. Later arriving axons innervate the PCA and MTA. Vocal fold function is improved as compared to controls. Anti-GDNF injection into the PCA influences the pattern of reinnervation and may result in less synkinetic, more functional innervation.

Level Of Evidence: NA Laryngoscope, 126:E337-E342, 2016.
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http://dx.doi.org/10.1002/lary.25953DOI Listing
October 2016

Complementary and alternative medicine iron preparations: A cost-effective, rationale and accessible solution for public health problems.

Adv Biomed Res 2015 27;4:137. Epub 2015 Jul 27.

Department of Pharmacology and Orthopaedics, Shaheed Hasan Khan Mewati Government Medical College, Nalhar, Mewat, Haryana, India.

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http://dx.doi.org/10.4103/2277-9175.161534DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4544128PMC
August 2015

Jumbo Cutter for Removal of A Bent Femoral Interlocking Nail: A Cost Effective Method.

J Clin Diagn Res 2015 Jun 1;9(6):RD06-7. Epub 2015 Jun 1.

Senior Resident, Department of Orthopaedics, SHKM Govt Medical College Nalhar (Mewat) Nuh , Haryana, India .

Closed diaphyseal femoral shaft fractures can be treated with multiple surgical options. It is more challenging to remove a bent nail than a broken one because it is difficult to retrieve the bent nail through the intramedullary canal. Various authors have published their techniques for removal of bent femoral interlocking nail. This article describes a simple technique using Jumbo cutter for sectioning and removal of bent interlocking nail. This technique will help orthopaedic surgeons to remove bent nail without using any specialised metal cutting instruments.
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http://dx.doi.org/10.7860/JCDR/2015/13824.6055DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4525562PMC
June 2015

Glia-neuron interactions in the mammalian retina.

Prog Retin Eye Res 2016 Mar 23;51:1-40. Epub 2015 Jun 23.

Department of Ophthalmology, Cell Biology and Anatomy, New York Medical College, Valhalla, NY 10595, USA; IKERBASQUE, Basque Foundation for Science at Dept. Cell Biology and Histology, UPV/EHU, Spain.

The mammalian retina provides an excellent opportunity to study glia-neuron interactions and the interactions of glia with blood vessels. Three main types of glial cells are found in the mammalian retina that serve to maintain retinal homeostasis: astrocytes, Müller cells and resident microglia. Müller cells, astrocytes and microglia not only provide structural support but they are also involved in metabolism, the phagocytosis of neuronal debris, the release of certain transmitters and trophic factors and K(+) uptake. Astrocytes are mostly located in the nerve fibre layer and they accompany the blood vessels in the inner nuclear layer. Indeed, like Müller cells, astrocytic processes cover the blood vessels forming the retinal blood barrier and they fulfil a significant role in ion homeostasis. Among other activities, microglia can be stimulated to fulfil a macrophage function, as well as to interact with other glial cells and neurons by secreting growth factors. This review summarizes the main functional relationships between retinal glial cells and neurons, presenting a general picture of the retina recently modified based on experimental observations. The preferential involvement of the distinct glia cells in terms of the activity in the retina is discussed, for example, while Müller cells may serve as progenitors of retinal neurons, astrocytes and microglia are responsible for synaptic pruning. Since different types of glia participate together in certain activities in the retina, it is imperative to explore the order of redundancy and to explore the heterogeneity among these cells. Recent studies revealed the association of glia cell heterogeneity with specific functions. Finally, the neuroprotective effects of glia on photoreceptors and ganglion cells under normal and adverse conditions will also be explored.
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http://dx.doi.org/10.1016/j.preteyeres.2015.06.003DOI Listing
March 2016

Differential expression of glial-derived neurotrophic factor in rat laryngeal muscles during reinnervation.

Laryngoscope 2014 Dec 15;124(12):2750-6. Epub 2014 Sep 15.

Department of Anatomy and Cell Biology, New York Medical College, Valhalla, New York.

Objectives/hypothesis: Nonspecific, synkinetic reinnervation is one of the causes of poor functional recovery after a peripheral nerve lesion. Knowledge of the differential expression of neurotrophic factors that subserve axon guidance, as well as neuromuscular junction formation and maintenance in the denervated muscles, may allow appropriate interventions that will improve the functional nonsynkinetic reinnervation.

Study Design: Laboratory experiment.

Methods: The expression of glial-derived neurotrophic factor (GDNF) was studied in the abductor and adductor muscles of the larynx in the rat utilizing real-time polymerase chain reaction at different times following transection, anastomosis, and reinnervation of the right recurrent laryngeal nerve (RLN). Immunostaining of GDNF, axons, and the motor endplates were performed. This data was correlated with intramuscular mRNA GDNF expression.

Results: Significant upregulation of GDNF was observed until 14 days after RLN injury. The highest level of the GDNF expression was reached at different times in posterior cricoarytenoid (PCA), lateral thyroarytenoid (LTA), and medial thyroarytenoid (MTA). These expression peaks correlated with the timing of reinnervation observed on immunohistochemistry, where PCA was reinnervated first, followed by MTA and LTA.

Conclusion: Differences of GDNF expression are linked to the differential timing of RLN axon regeneration and individual muscle reinnervation. The present finding suggests the need to further investigate the role of GDNF and other neurotrophic factors in the timing of reinnervation, axon guidance, and neuromuscular junction formation as it relates to synkinetic and nonsynkinetic RLN reinnervation. Future experimental results may provide insight to therapeutic options that could stimulate appropriate neuromuscular junction formation and nonsynkintic functional reinnervation following RLN injury.
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http://dx.doi.org/10.1002/lary.24759DOI Listing
December 2014

Evaluation of clinical diagnosis by knee arthroscopy.

J Indian Med Assoc 2013 Feb;111(2):86-8

Department of Orthopaedics, Himalayan Institute of Medical Sciences, Dehradun 248140.

This prospective study was carried out in the orthopaedic department of a medical college to evaluate the accuracy of clinical diagnosis by knee arthroscopy. The reliability of clinical assessment (history and physical examination) was determined by comparing the initial pre-operative diagnosis with the postoperative diagnosis as determined by arthroscopy. The study group included 50 patients (50 knees) scheduled for arthroscopic surgery for suspected internal derangements of knees. The primary pre-operative diagnosis was fully correct in 16 cases (32%), partially correct in 16 cases (32%), and incorrect in 18 cases (36%), with an overall accuracy of 81%, sensitivity 82% and specificity 62%. The most common pre-operative diagnosis was medial meniscal tear and anterior cruciate ligament tear. The results of clinical assessment were comparable to the published reports. Though the present study suggests that the diagnostic value of arthroscopy is higher than clinical examination but it also makes it apparent that the two techniques complement each other and are more accurate when taken together than individually.
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February 2013

Development of the rat larynx: a histological study.

Laryngoscope 2013 Dec 5;123(12):3093-8. Epub 2013 Aug 5.

Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York, U.S.A.

Objectives/hypothesis: To evaluate and describe the cartilaginous and muscular development of the rat larynx.

Study Design: Histologic evaluation.

Methods: The larynges of Sprague Dawley rats of embryonic day (E) 13, 15, 17, 19, 21, postnatal day 0, 14, and adult of 250 gm were collected. Four larynges of each age were harvested, cut into 15-μm serial sections, stained with hematoxylin and eosin, and evaluated under light microscopy. Representative digital images were recorded and evaluated at the preglottic (supraglottic in humans), glottic, and postglottic (subglottic in humans) levels.

Results: Brachial arches were observed at E13. At E17, immature structures of the larynx, including skeletal muscle, cartilage, and the lumen were identifiable. Chondrification and muscle formation were clearly seen by E19. The muscular and cartilagenous components of the larynx were well established by E21. During the span between birth and adult maturation, the size of the larynx increased from a height of 1.10 mm to 2.90 mm, and from a width of 1.80 mm to 5.40 mm, and from a length of 1.38 mm to 4.77 mm in the stained section. Although developed at E21, the laryngeal structures continued to grow by approximately 30%.

Conclusion: Rat laryngeal development parallels that in mice and humans. In the rat, at E17 immature structures of the larynx are identifiable, they are well developed at birth and grow by approximately 30% into adulthood. Understanding the chronology and morphology of the embryogenesis of the rat laryngeal musculature is essential and will allow for further evaluation of the embryologic innervation of these muscles.
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http://dx.doi.org/10.1002/lary.24145DOI Listing
December 2013

Embryologic innervation of the rat laryngeal musculature--a model for investigation of recurrent laryngeal nerve reinnervation.

Laryngoscope 2013 Dec 25;123(12):3117-26. Epub 2013 Jun 25.

New York Eye and Ear Infirmary, Department of Otolaryngology, Voice and Swallowing Institute, New York, New York.

Objectives/hypothesis: Optimal management of vocal fold paralysis would entail recurrent laryngeal nerve (RLN) reinnervation resulting in normal vocal fold motion. Unfortunately, RLN reinnervation currently results in a nonfunctional vocal fold due to synkinetic reinnervation. Therapeutic interventions that guide regenerating axons back to the appropriate muscle would prevent synkinesis and restore vocal fold and glottal function. The initial step toward developing these therapies is the elucidation of the embryologic innervation of the larynx. This study aimed to identify the age of occurrence, timing, and pattern of embryologic innervation of the rat larynx, hypothesizing that differences in these parameters exist between distinct laryngeal muscles.

Study Design: Descriptive anatomic study.

Methods: The larynx of rats aged embryologic day (E) 15, 16, 17, 19, and 21 were harvested and then sectioned. Two rats were used for each age. Sections were colabeled with neuronal class III β-tubulin polyclonal antibody to identify the presence of axons and alexa 488 conjugate α-bungarotoxin to identify the presence of motor endplates. The age at which axons and motor endplates were first present was noted. The position and pattern of the axons and motor endplates was recorded in relation to each other as well as the musculoskeletal anatomy of the larynx. The time at which axons appeared to innervate the medial thyroarytenoid (MTA) muscle, lateral thyroarytenoid (LTA) muscle, and the posterior cricoarytenoid (PCA) muscle was documented.

Results: Findings in the rat suggest the RLN reaches the larynx and begins branching by E15. Axons branch dorsally first and reach the PCA muscle before the other muscles. Branching toward the MTA muscle occurs only after axons have reached the LTA muscle. By E19, RLN axons have been guided to and selected their respective muscles with formation of neuromuscular junctions (NMJs) in the PCA, LTA and MTA muscles, though the formation of NMJs in the MTA muscle was comparatively delayed.

Conclusions: This study describes the embryologic innervation of the rat larynx and suggests that there are distinct differences in the age of occurrence, timing, and pattern of innervation of the PCA, LTA, and MTA muscles of the rat. These findings lay the foundation for studies investigating the role of guidance cues in RLN axon guidance and the utility of these cues in the treatment of RLN injury via the stimulation of functional, nonsynkinetic reinnervation.
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http://dx.doi.org/10.1002/lary.24216DOI Listing
December 2013

Recurrent laryngeal nerve transection and anastomosis: rat laryngeal motoneuron survival and effect of the anastomosis site.

Ann Otol Rhinol Laryngol 2013 Apr;122(4):283-7

Department of Otolaryngology, Voice and Swallowing Institute, New York Eye and Ear Infirmary, 310 E 14th St, 6th Floor, New New York, NY 10003, USA.

Objectives: We investigated the quantity of recurrent laryngeal nerve motoneurons (RLNMs) that survive after transection and anastomosis of the rat recurrent laryngeal nerve (RLN), as well as the impact of the anastomosis site on RLN regeneration.

Methods: Ten rats underwent right RLN transection and anastomosis. After 16 weeks, Fluoro-Ruby (FR) was applied to the RLN that was transected proximal or distal to the anastomosis site. The brain stems were harvested, and the nucleus ambiguus was evaluated for labeled RLNMs. The RLNM counts were compared to each other and to those from 3 control rats in which FR was applied to an acutely transected RLN.

Results: The number of RLNMs that were stained after RLN transection, anastomosis, and regeneration was consistent with the total number of RLNMs in the nucleus ambiguus of control rats. This finding confirms that most RLNMs survived after RLN transection and anastomosis. The quantity of labeled RLNMs was statistically similar whether the FR was applied proximal or distal to the anastomosis, implying that most of the viable axons that were present proximal to the anastomosis crossed into the distal nerve.

Conclusions: Rat RLNMs survive nerve transection, anastomosis, and regeneration. The anastomosis site does not significantly impede axonal regeneration, and most of the axons traverse the anastomosis into the distal nerve.
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http://dx.doi.org/10.1177/000348941312200412DOI Listing
April 2013

Neuroprotective effects of topical CB1 agonist WIN 55212-2 on retinal ganglion cells after acute rise in intraocular pressure induced ischemia in rat.

Exp Eye Res 2013 May 20;110:55-8. Epub 2013 Feb 20.

Department of Cell Biology and Histology, University of the Basque Country UPV/EHU, E-48940 Leioa, Vizcaya, Spain.

Neuroprotection in retinal experimental work consists primarily of preventing retinal ganglion cell (RGC) loss after exposure to a hostile event. We have studied the neuroprotective effect on RGCs in an ischemia-reperfusion model by activation of the cannabinoid receptor CB1 using topical application of WIN 55212-2. Intraocular pressure (IOP) was increased by continuous infusion of phosphate buffer saline (PBS) into the anterior chamber of the eye. Mean intraocular pressure was increased up to 88.5 ± 0.29 mm Hg (control normal IOP 15.1 ± 0.25 mm Hg), for 35 min. Animals were distributed in 3 groups. Left eyes underwent acute rise in intraocular pressure. First group was treated with topical Tocrisolve™ 100 in both eyes. Second group was treated with 1% solution of CB1 agonist WIN 55212-2 in both eyes. Third group was treated with WIN 55212-2 1% and CB1 antagonist AM 251 1% solutions in both eyes. Subsequently, RGCs were immunolabeled with Brn3a and automated quantification of retinal mosaics of RGCs were performed. The ischemic damage led to a mean loss in RGC density of 12.33%. After topic administration of WIN 55212-2, mean loss of RGCs was of 2.45%. Co-treatment with CB1 antagonist AM 251 abolished almost completely the neuroprotective effect of WIN 55212-2. Topic 1% WIN 55212-2 showed a neuroprotective effect on RGC degeneration after ischemia-reperfusion without pre-activation of CB1 receptors.
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http://dx.doi.org/10.1016/j.exer.2013.02.009DOI Listing
May 2013

Quantity and three-dimensional position of the recurrent and superior laryngeal nerve lower motor neurons in a rat model.

Ann Otol Rhinol Laryngol 2011 Nov;120(11):761-8

Department of Otolaryngology, New York Eye and Ear Infirmary, New York, NY 10003. USA.

Objectives: We sought to elucidate the 3-dimensional position and quantify the lower motor neurons (LMNs) of the recurrent laryngeal nerve (RLN) and the superior laryngeal nerve (SLN) in a rat model. Quantification and mapping of these neurons will enhance the usefulness of the rat model in the study of reinnervation following trauma to these nerves.

Methods: Female Sprague-Dawley rats underwent microsurgical transection of the RLN, the SLN, or both the RLN and SLN or sham surgery. After transection, either Fluoro-Ruby (FR) or Fluoro-Gold (FG) was applied to the proximal nerve stumps. The brain stems were harvested, sectioned, and examined for fluorolabeling. The LMNs were quantified, and their 3-dimensional position within the nucleus ambiguus was mapped.

Results: Labeling of the RLN was consistent regardless of the labeling agent used. A mean of 243 LMNs was documented for the RLN. The SLN labeling with FR was consistent and showed a mean of 117 LMNs; however, FG proved to be highly variable in labeling the SLN. The SLN LMNs lie rostral and ventral to those of the RLN. In the sham surgical condition, FG was noted to contaminate adjacent tissues--in particular, in the region of the SLN.

Conclusions: Fluorolabeling is an effective tool to locate and quantify the LMNs of the RLN and SLN. The LMN positions and counts were consistent when FR was used in labeling of either the RLN or the SLN. Fluoro-Gold, however, because of its tendency to contaminate surrounding structures, can only be used to label the RLN. Also, as previously reported, the SLN LMNs lie rostral and ventral to those of the RLN. This information results in further clarification of a rat model of RLN injury that may be used to investigate the effects of neurotrophic factors on RLN reinnervation.
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http://dx.doi.org/10.1177/000348941112001111DOI Listing
November 2011

Morphology of retinal vessels in the optic disk in a Göttingen minipig experimental glaucoma model.

Vet Ophthalmol 2012 Mar 8;15 Suppl 1:36-46. Epub 2011 Aug 8.

Department of Ophthalmology, Hospital de Cruces, University of the Basque Country (UPV/EHU), Vizcaya, Spain.

Objective: To compare the morphology of normal, healthy Gottingen minipig retinal vessels of the optic disk with experimentally induced glaucomatous optic disks in order to identify the glaucomatous excavation. Present results were compared to human glaucoma findings.

Procedure: Sixteen eyes from eight Göttingen minipigs were studied using fundoscopic photography and fluorescein angiography. Experimental glaucoma was then induced in the left eyes over 14 months, and changes in the optic disk vessels were assessed using fundoscopic photography and fluorescein angiography. The changes were compared with those previously reported in humans.

Results: Regarding the number of vessels, the location from where they emerge and the sectors of the optic disk that they cross, arterial and retinal vessels in Göttingen minipigs present a more asymmetric layout than in humans. The central excavation is filled by the central venous ring. Changes in the glaucomatous optic disk include arteriolar incurvation, and sometimes, nasal, and peripheral displacement of the arterioles that emerge between the ganglion cell axons of the neuroretinal ring. No angiographic changes were observed in the experimental glaucoma model.

Conclusions: The changes in the glaucomatous optic disk of the minipig imply a predominant involvement of the arterioles. However, in humans with primary open-angle glaucoma (POAG), both the arterioles and the venules are displaced, and the central excavation is easier to distinguish, because of the absence of a central venous ring.
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http://dx.doi.org/10.1111/j.1463-5224.2011.00937.xDOI Listing
March 2012

Giant benign nodular hidradenoma of the shoulder: A rare tumor in orthopedic practice.

Int J Shoulder Surg 2010 Oct;4(4):93-6

Department of Orthopaedics, Himalayan Institute of Medical Sciences, Doiwala, Jolly Grant, Dehradun, Uttarakhand, India.

A clear cell hidradenoma is a rare dermal tumor, which is believed to originate from the apical portion of the sweat glands. The usual size reported is 5-30 mm. It is generally found in the head, face, and upper extremity regions. This lesion has not been reported to be large enough to impinge a joint range of motion. Hence, its description in the orthopedic literature is extremely rare. We present a giant benign nodular hidradenoma presenting as painful restriction of the right shoulder joint in a 35-year-old male.
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http://dx.doi.org/10.4103/0973-6042.79793DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3100814PMC
October 2010

Electromyographic and histologic evolution of the recurrent laryngeal nerve from transection and anastomosis to mature reinnervation.

Laryngoscope 2011 Feb;121(2):325-31

Department of Otolaryngology, The New York Eye and Ear Infirmary, New York, New York 10003, USA.

Objectives: To describe the natural evolution of recurrent laryngeal nerve (RLN) reinnervation in an animal model.

Study Design: Twenty Sprague Dawley rats underwent unilateral RLN transection and anastomosis. Animals were sacrificed at 4, 8, 12, 16, and 20 weeks. Prior to sacrifice, each rat underwent electromyography (EMG) and visual grading of vocal fold motion. Bilateral RLNs were harvested and evaluated histologically.

Results: EMG revealed synkinetic reinnervation at all time periods except at 4 weeks. EMG evolution plateaued at 16 weeks. Vocal fold motion was slight in three rats at 4 weeks but was otherwise absent except for one rat at 12 weeks. Histologic changes of the axons and their myelin sheaths were consistent at each time period. At 16 weeks, histologic changes plateaued.

Conclusions: Consistent EMG, histologic, and vocal fold motion changes occur at specific time periods during RLN reinnervation after transection and anastomosis in a rat model. Reinnervation is mature at 16 weeks. Findings corroborate theories of preferential and synkinetic reinnervation after RLN transection. Use of a rat model to investigate the effect of interventions on RLN reinnervation requires a minimum of 16 weeks between transection and investigation to allow for maturation of reinnervation.
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http://dx.doi.org/10.1002/lary.21290DOI Listing
February 2011

Experimental posterolateral spinal fusion with beta tricalcium phosphate ceramic and bone marrow aspirate composite graft.

Indian J Orthop 2010 Oct;44(4):402-8

Departments of Orthopaedic Surgery and Pathology, Himalayan Institute of Medical Sciences, Swami Ram Nagar, Jollygrant, Doiwala, Dehradun- Uttarakhand, India.

Background: Beta tricalcium phosphate is commonly used in metaphyseal defects but its use in posterolateral spinal fusion remains controversial. There are very few published animal studies in which use of beta tricalcium phosphate has been evaluated in the posterolateral lumbar arthrodesis model. Hence we conducted a study to evaluate the potential of composite graft of beta tricalcium phosphate and bone marrow aspirate in comparison to autologous bone graft, when used for posterolateral spinal fusion.

Materials And Methods: Single level posterolateral lumbar fusion was performed in 40 adult male Indian rabbits, which were assigned randomly into one of the four groups based on graft materials implanted; a) 3 gm beta tricalcium phosphate plus 3 ml bone marrow aspirate (Group I); b) 3 ml bone marrow aspirate alone (Group II); c) 3 gm beta tricalcium phosphate (Group III) and d) 3 gm autologous bone graft (Group IV). Each group had 10 rabbits. Half of the rabbits were sacrificed by injecting Phenobarbitone intraperitoneally after eight weeks and the remaining after 24 weeks, and were evaluated for fusion by X-rays, computed tomography (CT) scans, manual palpation test and histology.

Results: Beta tricalcium phosphate used with bone marrow aspirate produced best results when compared to other groups (P =.0001). When beta tricalcium phosphate was used alone, fusion rates were better as compared to fusion achieved with autologous iliac crest bone graft though statistically not significant (P =0.07). Autologous bone graft showed signs of new bone formation. However, the rate of new bone formation was comparatively slow.

Conclusion: Composite graft of beta tricalcium phosphate and bone marrow aspirate can be used as an alternative to autologous iliac crest bone graft.
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http://dx.doi.org/10.4103/0019-5413.67118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2947727PMC
October 2010

Deficient histone acetylation and excessive deacetylase activity as epigenomic marks of prostate cancer cells.

Int J Oncol 2009 Dec;35(6):1417-22

Department of Oncology, The First Affiliated Hospital, Zhengzhou University, Zhengzhou, Henan 450052, P.R. China.

Aberrant epigenomic alterations include incorrect histone modifications involving altered expression of chromatin-modifying proteins. They contribute to gene silencing and carcinogenesis. The nature of the epigenomic alterations occurring with prostate cancer remains to be fully identified. The acetylation status of histone H3 in human prostate cancer cells was assessed with multiple acetylation sites at N-termini. In contrast to the non-malignant prostatic cell lines RC165N/h and RC170N/h which possess stem cell properties, cancer cell lines LNCaP, DU-145, and PC-3 were either not acetylated or reduced in density (50-70%), at N-termini lysines 9, 14, 18, and 23 of histone H3. Deficient acetylation of histone H3 was similarly detected with clinical prostatic adenocarcinomas as compared to normal tissues. Cancer cell lines and adenocarcinomas exhibited varied acetylation status at particular lysines, indicating the possible presence of deacetylation patterns reflecting individual cancer cell clones. A significantly elevated activity of histone deacetylases (HDACs) was determined in both cancer cell lines and adenocarcinomas. Inhibition of HDACs enhanced histone acetylation and p21 gene expression, indicating that excessive HDAC activity is a requisite for deficient histone acetylation. Deficient histone acetylation involving excessive HDAC activity may represent epigenomic features of prostate cancer cells, and the aberrant enzyme activity is probably an underlying cause of disrupting the epigenomes of normal prostatic cells.
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http://dx.doi.org/10.3892/ijo_00000459DOI Listing
December 2009

Transplantation of free tibial periosteal grafts for the repair of articular cartilage defect: An experimental study.

Indian J Orthop 2009 Oct;43(4):335-41

Department of Orthopaedic Surgery, Himalayan Institute of Medical Sciences, Swami Ram Nagar, Jollygrant, Doiwala, Dehradun, Uttarakhand - 248 140, India.

Background: Articular chondrocytes have got a long lifespan but rarely divides after maturity. Thus, an articular cartilage has a limited capacity for repair. Periosteal grafts have chondrogenic potential and have been used to repair defects in the articular cartilage. The purpose of the present study is to investigate the differentiation of free periosteal grafts in the patellofemoral joint where the cambium layer faces the subchondral bone and to investigate the applicability of periosteal grafts in the reconstruction of articular surfaces.

Materials And Methods: The study was carried out over a period of 1 year on 25 adult, male Indian rabbits after obtaining permission from the institutional animal ethical committee. A full-thickness osteochondral defect was created by shaving off the whole articular cartilage of the patella of the left knee. The defect thus created was grafted with free periosteal graft. The patella of the right knee was taken as a control where no grafting was done after shaving off the articular cartilage. The first animal was used to study the normal histology of the patellar articular cartilage and periosteum obtained from the medial surface of tibial condyle. Rest 24 animals were subjected to patellectomy, 4 each at serial intervals of 2, 4, 8, 16, 32 and 48 weeks and the patellar articular surfaces were examined macroscopically and histologically.

Results: The grafts got adherent to the underlying patellar articular surface at the end of 4 weeks. Microscopically, graft incorporation could be appreciated at 4 weeks. Mesenchymal cells of the cambium layer were seen differentiating into chondrocytes by the end of 4 weeks in four grafts (100%) and they were arranged in a haphazard manner. Till the end of 8 weeks, the cellular arrangement was mostly wooly. At 16 weeks, one graft (25%) had wooly arrangement of chondrocytes and three grafts (75%) had columnar formation of cells. Same percentage was maintained at 32 weeks. Four grafts (100%) at 48 weeks showed columnar orientation. The control side showed no changes over the shaved off articular surface in all the rabbits. One rabbit at 4 weeks had a dislocation of the patella on the control side. None of the rabbits developed any infection or wound dehiscence.

Conclusion: Autologous periosteal graft transplantation can be a promising substitute for articular cartilaginous defects.
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http://dx.doi.org/10.4103/0019-5413.55973DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2762553PMC
October 2009

Evaluation of hydroxyapatite and beta-tricalcium phosphate mixed with bone marrow aspirate as a bone graft substitute for posterolateral spinal fusion.

Indian J Orthop 2009 Jul;43(3):234-9

Department of Orthopaedic Surgery, Himalayan Institute of Medical Sciences, Swami Ram Nagar, Jollygrant, Doiwala, Dehradun- Uttarakhand-248 140, India.

Background: Autologous cancellous bone is the most effective biological graft material. However, harvest of autologous bone is associated with significant morbidity. Since porous hydroxyapatite and beta-tricalcium phosphate are biodegradable materials and can be replaced by bone tissue, but it lacks osteogenic property. We conducted a study to assess their use as a scaffold and combine them with bone marrow aspirate for bone regeneration using its osteogenic property for posterolateral spinal fusion on one side and autologous bone graft on the other side and compare them radiologically in terms of graft incorporation and fusion.

Materials And Methods: Thirty patients with unstable dorsal and lumbar spinal injuries who needed posterior stabilization and fusion were evaluated in this prospective study from October 2005 to March 2008. The posterior stabilization was done using pedicle screw and rod assembly, and fusion was done using hydroxyapatite and beta-tricalcium phosphate mixed with bone marrow aspirate as a bone graft substitute over one side of spine and autologous bone graft obtained from iliac crest over other side of spine. The patients were followed up to a minimum of 12 months. Serial radiographs were done at an interval of 3, 6, and 12 months and CT scan was done at one year follow-up. Graft incorporation and fusion were assessed at each follow-up. The study was subjected to statistical analysis using chi-square and kappa test to assess graft incorporation and fusion.

Results: At the end of the study, radiological graft incorporation and fusion was evident in all the patients on the bone graft substitute side and in 29 patients on the autologous bone graft side of the spine (P > 0.05). One patient showed lucency and breakage of distal pedicle screw in autologous bone graft side. The interobserver agreement (kappa) had an average of 0.72 for graft incorporation, 0.75 for fusion on radiographs, and 0.88 for the CT scan findings.

Conclusion: Hydroxyapatite and beta-tricalcium phosphate mixed with bone marrow aspirate seems to be a promising alternative to conventional autologous iliac bone graft for posterolateral spinal fusion.
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http://dx.doi.org/10.4103/0019-5413.49387DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2762171PMC
July 2009

Observations of recurrent laryngeal nerve injury and recovery using a rat model.

Laryngoscope 2009 Aug;119(8):1644-51

Department of Otolaryngology, the New York Eye and Ear Infirmary, New York and New York Medical College, Valhalla, USA.

Objectives/hypothesis: To evaluate standardized recurrent laryngeal nerve (RLN) injuries using a rat model via minimally invasive transoral electromyography (ToL EMG) and histologic studies.

Methods: Forty-two female Sprague Dawley rats weighing 200 g to 250 g underwent crush injury to the right RLN using a calibrated pressure clip (0.61 N or 1.19 N) for 60 seconds. Following injury, serial ToL EMGs were performed on abductor and adductor laryngeal muscles during respiratory cycles and spontaneous vocal fold abduction on day 4 and then weekly for 6 weeks. Vocal fold motion associated with spontaneous respiration was graded from 0 to 4. Rats were sacrificed at different time points for histologic evaluation of injured nerves.

Results: EMG signals showed fibrillation potentials on day 4 in all experimental conditions. Crushed RLN, regardless of force, exhibited polyphasic potentials at 2 weeks postinjury. Normal motor unit potentials and recruitment patterns were observed in EMG signals at 4 weeks for all 0.61 N clip animals. Six weeks following crush injury, motor unit potentials having normal appearance were observed in most animals. Synkinetic EMG signals were observed at 5 weeks and 6 weeks in the 1.19 N clip animals. Endoscopic evaluation of vocal fold mobility was consistently normal at 6 weeks only following 0.61 N crush injury.

Conclusions: This model is useful to simulate intraoperative RLN injuries and to better understand the electrophysiologic events during nerve recovery. The severity of injury to the RLN dictates histologic, neurologic and functional recovery of the laryngeal motor system. This model is useful to evaluate the efficacy of systemic and local neurotropic agents in the treatment of RLN injury.
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http://dx.doi.org/10.1002/lary.20293DOI Listing
August 2009

Neuroprotectin D1 inhibits retinal ganglion cell death following axotomy.

Prostaglandins Leukot Essent Fatty Acids 2008 Dec 18;79(6):201-7. Epub 2008 Nov 18.

Department of Cell Biology and Anatomy and Ophthalmology, New York Medical College, Valhalla, NY 10595, USA.

Neuroprotectin D1 (NPD1), a docosahexaenoic acid-derived autacoid, is an endogenous neuroprotective and anti-inflammatory mediator that is generated in the retina and brain. The effects of exogenous NPD1 on retinal ganglion cell (RGC) apoptosis and the role of 12/15-lipoxygenase (Alox15) in retina were evaluated after optic nerve transection (ONT). Treatment with NPD1 was associated with significant protection against RGC death. The percentage of RGC survival in NPD1-treated group was 30% at 2 weeks after ONT as compared with 12% of RGC survival in the ONT group without treatment. Endogenous NPD1 was a predominant lipid autocoid in uninjured and axotomized retinas. Alox15 mRNA expression was upregulated in retinas following ONT suggesting that amplification of 12/15-lipoxygenase (12/15-LOX) may represent a neuroprotective response in the rat retina. The density of RGCs was higher in the normal retina of 12/15-LOX-deficient mice as compared with congenic controls. Hence, the resident NPD1 has a potential role in the physiological and pathophysiological responses of the retina.
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http://dx.doi.org/10.1016/j.plefa.2008.09.022DOI Listing
December 2008

Evaluation of functional recovery of recurrent laryngeal nerve using transoral laryngeal bipolar electromyography: a rat model.

Ann Otol Rhinol Laryngol 2008 Aug;117(8):604-8

Department of Otolaryngology, New York Eye and Ear Infirmary, New York, NY 10003, USA.

Objectives: We developed a standardized method of minimally invasive transoral laryngeal (ToL) bipolar electromyography (EMG) for evaluation of recurrent laryngeal nerve (RLN) recovery after a controlled crush injury in a rat model.

Methods: Ten 200- to 250-g Sprague-Dawley rats underwent a controlled crush injury to the left RLN performed with 60 seconds of use of a calibrated aneurysm clamp with a closing force of 0.61 N. Serial ToL bipolar EMG was performed on adductor muscles and the posterior criocoarytenoid muscle during spontaneous vocal fold motion under anesthesia. Each animal underwent ToL EMG immediately after surgery and 1, 3, and 6 weeks after surgery.

Results: The EMG signals showed normal motor unit potentials and recruitment patterns 3 weeks after crush injury. Endoscopic evaluation of vocal fold mobility yielded consistently normal findings 6 weeks after crush injury.

Conclusions: We have developed a standardized method of crush injury to the rat RLN model and a minimally invasive transoral bipolar spontaneous EMG technique to serially evaluate and follow nerve injury and recovery in rats. This model is intended to simulate intraoperative RLN injury, to elucidate the electrophysiological events that occur during nerve recovery, and to form the basis for studying agents to enhance such recovery.
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http://dx.doi.org/10.1177/000348940811700810DOI Listing
August 2008
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