The Prevalance of Congenital Optic Disc Anomalies in Turkey: A Hospital-Based Study

Purpose: The aim of this study was to investigate the prevalance of congenital optic disc (OD) anomalies in Turkey. Methods: The 11149 eyes of 5583 patients were screened for OD anomalies. All patients were underwent a complete ophthalmic examination including best corrected visual acuity, refraction, spherical equivalent, slit lamp biomicroscopy, intraocular pressure measurements, dilated stereoscopic fundus examination. Data analyses were performed by using SPSS for Windows, version 22.0 (SPSS Inc., Chicago, IL, United States).Results: 11149 eyes of 5583 participants were screened. Of the 5583 participants who underwent OD examination, 186 (3,3%) were found to be abnormal. 266 of 11149 (2,38%) eyes were found OD anomalies. 98 (52,7%) were female, 88 (47,3%) were male and the mean of age was 44,05±15,73 years. The prevalence of all congenital OD anomalies was found 3,3%. The tilted disc was the most common anomaly and was found at least one eye in 46 patients (75 eyes) and 0.82% of all screened patients. Peripapillary myelinated nerve fibres was the second common anomaly and was found at least one eye in 29 subjects (35 eyes) and 0,51% of all screened subjects. Peripapillary atrophy was the third common anormality, and was found in at least one eye in 24 patients (37 eyes) and 0,42% of all screened subjects.Conclusion: To our knowledge, this is the first study that the prevalences of all congenital optic disc anomalies from Turkey. The prevalence of congenital optic disc anomalies is higher than in other countries.

Exercise rather than fluoxetine promotes oligodendrocyte differentiation and myelination in the hippocampus in a male mouse model of depression

Although selective serotonin reuptake inhibitor (SSRI) systems have been meaningfully linked to the clinical phenomena of mood disorders, 15–35% of patients do not respond to multiple SSRI interventions or even experience an exacerbation of their condition. As we previously showed, both running exercise and fluoxetine reversed depression-like behavior. However, whether exercise reverses depression-like behavior more quickly than fluoxetine treatment and whether this rapid effect is achieved via the promotion of oligodendrocyte differentiation and/or myelination in the hippocampus was previously unknown. Sixty male C57BL/6 J mice were used in the present study. We subjected mice with unpredictable chronic stress (UCS) to a 4-week running exercise trial (UCS + RN) or intraperitoneally injected them with fluoxetine (UCS + FLX) to address these uncertainties. At the behavioral level, mice in the UCS + RN group consumed significantly more sugar water in the sucrose preference test (SPT) at the end of the 7th week than those in the UCS group, while those in the UCS + FLX group consumed significantly more sugar water than mice in the UCS group at the end of the 8th week. The unbiased stereological results and immunofluorescence analyses revealed that running exercise, and not fluoxetine treatment, increased the numbers of CC1+ and CC1+/Olig2+/BrdU+ oligodendrocytes in the CA1 subfield in depressed mice exposed to UCS. Moreover, running exercise rather than fluoxetine increased the level of myelin basic protein (MBP) and the G-ratio of myelinated nerve fibers in the CA1 subfield in the UCS mouse model. Unlike fluoxetine, exercise promoted hippocampal myelination and oligodendrocyte differentiation and thus has potential as a therapeutic strategy to reduce depression-like behaviors induced by UCS.

Myelin Basic Protein and Cardiac Sympathetic Neurodegeneration in Nonhuman Primates

Minimal myelination is proposed to be a contributing factor to the preferential nigral neuronal loss in Parkinson’s disease (PD). Similar to nigral dopaminergic neurons, sympathetic neurons innervating the heart have long, thin axons which are unmyelinated or minimally myelinated. Interestingly, cardiac sympathetic loss in PD is heterogeneous across the heart, yet the spatial relationship between myelination and neurodegeneration is unknown. Here, we report the mapping of myelin basic protein (MBP) expression across the left ventricle of normal rhesus macaques (n = 5) and animals intoxicated with systemic 6-OHDA (50 mg/kg iv) to model parkinsonian cardiac neurodegeneration (n = 10). A subset of 6-OHDA-treated rhesus received daily dosing of pioglitazone (5 mg/kg po; n = 5), a PPARγ agonist with neuroprotective properties. In normal animals, MBP-immunoreactivity (-ir) was identified surrounding approximately 14% of axonal fibers within nerve bundles of the left ventricle, with more myelinated nerve fibers at the base level of the left ventricle than the apex p < 0.014 . Greater MBP-ir at the base was related to a greater number of nerve bundles at that level relative to the apex p < 0.05 , as the percent of myelinated nerve fibers in bundles was not significantly different between levels of the heart. Cardiac sympathetic loss following 6-OHDA was associated with decreased MBP-ir in cardiac nerve bundles, with the percent decrease of MBP-ir greater in the apex (84.5%) than the base (52.0%). Interestingly, cardiac regions and levels with more MBP-ir in normal animals showed attenuated sympathetic loss relative to areas with less MBP-ir in 6-OHDA + placebo (r = −0.7, p < 0.014 ), but not in 6-OHDA + pioglitazone (r = −0.1) subjects. Our results demonstrate that myelination is present around a minority of left ventricle nerve bundle fibers, is heterogeneously distributed in the heart of rhesus macaques, and has a complex relationship with cardiac sympathetic neurodegeneration and neuroprotection.

Age-Dependent Histomorphometrical Values of the Sciatic Nerve Regeneration in Rats after Cutting and Microsurgical Suturing

The effect of ageing on the morphofunctional features of nerves and the process of their posttraumatic regeneration has been studied in details. However, it is not known, whether there are differences of the neuroregeneration potential in the young, adult and mature experimental animals.The aim of the study was to evaluate histomorphometrical parameters of the rat sciatic nerve regeneration after cutting and microsurgical suturing depending on their age.Materials and Methods. The study included 15 white laboratory Wistar rats aged 5–6 (young), 8–10 (adult) and 12 months (mature). The sciatic nerve was transected at the level of the middle third of the thigh with microsurgical scissors and sutured with six epi-perineural stitches in the animals. In 4 months the animals were euthanized. Sections of sciatic nerves distal to the levels of sutures were put into araldite, semi-thin slices (0.5–1.0 mkm) were obtained for histomorphometric analysis. Thirteen intact animals were selected as control. Statistical processing was performed using nonparametric methods.Results. The numerical density of endoneural vessels in nerves of operated rats was higher than that in the intact ones, but in mature animals it was significantly lower than in young and adult ones (p<0.001). The numerical density of endoneural cells nuclei in young experimental animals did not differ from that of the intact ones, but in animals from the adult and mature groups it was more than four times higher than in animals from the young group (p<0.001). The numerical density of regenerating myelinated nerve fibers in animals of the young and adult groups did not differ from that of the intact nerve, in animals of the mature group it increased in 2.5 times (p<0.001). The numerical density of degenerating myelinated fibers in the operated animals of experimental groups was higher than in the intact group (two times, six times and 11 times higher, respectively). The diameter distribution of the regenerating myelinated fibers in animals of all groups differed from that of the intact control animals.Conclusions. The data obtained demonstrate a significant decrease in the regenerative potential of Schwann cells and neurons in adult and mature animals compared with the young ones.

Multi-Step Clustering Approach of Myelinated Nerve Fibers in Experimental Neuromorphology

One of the unresolved issues in experimental neuromorphology is searching for a solution for myelinated nerve fibers clustering on set of morphometric parameters. Therefore, in this article, a new approach for cluster analysis of myelinated fibers is proposed based on their morpho-functional features. The proposed clustering approach was developed in R software environment and uses model-based clustering, which is performed in few steps with increasing number of morphometric parameters on each next step. Applying the proposed clustering solution shown high similarity of identified groups' morphometric parameters with respective physiological types of myelinated A-fibers. This fact, in addition to the algorithm implementation simplicity, facilitates its use on identifying clusters of myelinated fibers that represent different myelinated fibers subpopulation in experimental neuromorphological research with high level of reliability.

The Adverse Effect of Mobile Phone Radiations on Dorsal Root Ganglion of Albino Rats

Objectives: To assess the effect of Mobile Phone Radio Frequency Electromagnetic Radiation (RF-EMR) on the histological structure of dorsal root ganglia in albino rats. Methods: Twenty-four albino rats divided into one control and three experimental groups were studied for four weeks. The experimental groups were exposed to three different levels of RF-EMR through complete missed calls of 80,120 and160 calls per day respectively, using a GSM mobile phone of 0.9GHz to1.8 GHz in silent mode. The dorsal root ganglia of the sacrificed Rats were examined under light and transmission electron microscope (TEM). Results: Dorsal root ganglions of exposed rats showed considerable histological changes like reduction in cell size, condensation of cytoplasm, peripherally located heterochromatin nucleus, loss of nucleolus and densely packed myelinated nerve fibers. No such changes were observed in control rats. Conclusion: Dorsal root ganglionic cells showed enduring and continuous changes when exposed to RF-EMR. The severity of histomorphological changes was dose-dependent, which increased constantly with radiation dosage increment. It might be fair to conclude that degenerative changes in the Dorsal Root Ganglion of the spinal cord, could be attributed to the long-term exposure to RF-EMR.

Quantitative Assessment of Neuroinflammation, Myelinogenesis, Demyelination, and Nerve Fiber Regeneration in Immunostained Sciatic Nerves From Twitcher Mice With a Tissue Image Analysis Platform

Scoring demyelination and regeneration in hematoxylin and eosin–stained nerves poses a challenge even for the trained pathologist. This article demonstrates how combinatorial multiplex immunohistochemistry (IHC) and quantitative digital pathology bring new insights into the peripheral neuropathogenesis of the Twitcher mouse, a model of Krabbe disease. The goal of this investigational study was to integrate modern pathology tools to traditional anatomic pathology microscopy workflows, in order to generate quantitative data in a large number of samples, and aid the understanding of complex disease pathomechanisms. We developed a novel IHC toolkit using a combination of CD68, periaxin-1, phosphorylated neurofilaments and SOX-10 to interrogate inflammation, myelination, axonal size, and Schwann cell counts in sciatic nerves from 17-, 21-, 25-, and 35-day-old wild-type and Twitcher mice using self-customized digital image algorithms. Our quantitative analyses highlight that nerve macrophage infiltration and interstitial expansion are the earliest detectable changes in Twitcher nerves. By 17 days of age, while the diameter of axons is small, the number of myelinated axons is still normal. However, from 21 days onward Twitcher nerves contain 75% of wild-type myelinated nerve fiber numbers despite containing 3 times more Schwann cells. In 35-day-old Twitcher mice when demyelination is detectable, nerve myelination drops to 50%.

An Anatomic, Imaging, and Clinical Review of the Medial Longitudinal Fasciculus

The medial longitudinal fasciculus (MLF) is a paired, highly specialized, and heavily myelinated nerve bundle responsible for extraocular muscle movements, including the oculomotor reflex, saccadic eye movements an smooth pursuit, and the vestibular ocular reflex. Clinically, lesions of the MLF are classically associated with internuclear ophthalmoplegia. However, clinical manifestations of a lesion in the MLF may be more complex and variable. We provide an overview of the neuroanatomy, neurologic manifestations, and correlative examples of the imaging findings on brain MRI of MLF lesions to provide the clinician and radiologist with a more comprehensive understanding of the MLF and potential clinical manifestations for an MLF lesion.