Clinical Neuroscience

Electrophysiological alterations and general toxic signs obtained by subacute administration of titanium dioxide nanoparticles to the airways of rats

HORVÁTH Tamara, PAPP András, KOVÁCS Dávid, KÁLOMISTA Ildikó, KOZMA Gábor, VEZÉR Tünde

MARCH 30, 2017

Clinical Neuroscience - 2017;70(03-04)


Introduction and aims - Particles of titanium dioxide (TiO2) with typical size below 100 nm have gained a broad range of application by now, partly involving direct human exposure. Their known properties - high specific surface, mobility within the organism, induction of oxidative stress, release of inflammation mediators etc. - raise the possibility of nervous system damage but the available data regarding this are scarce and contradictory. Based on that, and the experiences with other metal oxide nanoparticles, the aim of the present study was to investigate certain general end nervous system toxic effects of TiO2 nanoparticles applied in the airways of rats. Materials and methods - Young adult Wistar rats (5 groups of 10 rats each) received, daily for 28 days, intratracheal instillations of titanium dioxide nanoparticles of ca. 10 nm diameter, suspended in 1% hydroxyethyl cellulose dissolved in phosphate-buffered saline, in the doses of 1, 3, and 10 mg/kg b. w. Vehicle controls received the suspension medium and there was also an untreated control group. During treatment, the rats’ body weight was measured, and their clinical state observed, daily. After the 28 days, spontaneous cortical activity, sensory evoked potentials and tail nerve action potential was recorded in urethane anesthesia, then the rats were dissected and tissue samples were taken for Ti level determination and biochemical measurements of some oxidative stress indicators. Results - The two higher doses reduced the rate of body weight gain significantly. Sensory evoked potentials and tail nerve action potential were significantly slowed, but the change in the spectrum of spontaneous cortical activity was not significant. Correlation of moderate strength was found between certain evoked potential parameters and brain Ti level and oxidative stress data. Conclusion - Our results underlined the possible neurotoxicity of TiO2 NPs but also the need for further investigations.



Further articles in this publication

Clinical Neuroscience

Procedural learning and its consolidation in autism spectrum disorder


Children with autism spectrum disorder (ASD) show altered learning and memory. A number of recent studies have debated whether procedural learning in ASD is intact or not. Our aim was to further assess the question of whether the implicit, non-conscious form of procedural learning in ASD children is intact or not, furthermore, how shifts towards a more explicit, attention-demanding task setting can alter this performance. We administered a modified version of the Alternating Serial Reaction Time (ASRT) Task to children with ASD and IQ- and age-matched typically developing (TD) children. The task consisted of alternating blocks of cued (explicit) and uncued (implicit probe) blocks, and was repeated after a 16-hour delay. We found that ASD and TD children showed similar sequence-specific learning in cued explicit blocks, however, on the uncued probe blocks ASD children performed better compared to TD children. After the 16-hour delay both groups showed retention of the previously acquired knowledge. Finally, when we investigated the performance in different parts of the blocks, we found that ASD children did not show an effect of fatigue by the second part of the blocks. Our results suggest that children with ASD have increased implicit procedural learning skills compared to TD children. Differences in cued (explicit) and uncued (implicit) settings indicate that children with ASD are not affected by the lack of explicit instructions in probe blocks, suggesting a resistance for changes in task settings. These findings can help in a more thorough planning of cognitive therapeutic setups for ASD children.

Clinical Neuroscience

Surveillance and management of patients with tuberous sclerosis complex

FOGARASI András, GYORSOK Zsuzsanna, BODÓ Tímea

Tuberous sclerosis complex (TSC) is an autosomal dominant disease due to the uncontrolled differentiation, proliferation, and migration of cells in several organs. Clinical expression is highly variable, from mild skin findings and asymptomatic brain lesions to seizures, mental retardation, autism, and potentially fatal kidney, cardiac, or pulmonary disease. Aim of this paper is to summarize the diagnostic criteria, surveillance and therapeutic issues of this multisystemic disorder emphasizing the most important neurological consequences. Presenting the state-of-the-art management recommendations and comparing them with the local protocols, we hope that our review might help in the proper assessment of one of the most important single gene disorder.

Clinical Neuroscience

[Multilocus genetic analysis implicates neurodevelopment and immune system in the etiology of schizophrenia]

PULAY Attila József, KOLLER Júlia, NAGY László, MOLNÁR Mária Judit, RÉTHELYI János

[Background - Schizophrenia is a severe psychiatric disorder of poorly understood etiology, characterized by high heritability, multifactorial inheritance and high heterogeneity. Multilocus associaton methods may reduce the genetic heterogeneity and improve the probability of replication between analyses. Objectives - The aims of our study were twofold: 1. To analyse genetic risk factors of schizophrenia by using multilocus genetic tests. 2. To assess the replication probability attributable to the various multilocus tests. Subjects - Discovery set: case-parent trios of unaffected parents and affected probands with a DSM-IV schizophrenia diagnosis (n=16); replication set: schizophrenia cases and unaffected controls (n=5337). Methods - Associations of single nucleotide and indel markers were transferred to gene- and geneset-based associations, furthermore to geneset-enrichment tests and functional annotation cluster analyses in a two-staged designs. Associations with p<0.1 from the discovery set were tested in the replication sample. Familywise p-value correction for multiple comparisons were performed during the replication step. Results - After correction for multiplicity, no significant association or enrichment were detected for gene-based nor canonical pathway analyses, but significant association of the 14q31 cytoband and enrichments of the 5q31 and Xq13 cytobands were found (p_corr: 0.002, 0.006 and 0.048, respectively). Functional annotation clustering yielded statistically significant enrichment scores for clusters of splicing/alternative splicing, neurodevelopment and embryonic development. Improvements in replication probabilty were found with increased test complexity (P_rep: 0, 0.015, 0.21). Conclusions - Our results corroborate the involvement of neurodevelopment, synaptic plasticity and immune mechanisms in the etiology of schizophrenia. Also, our findings indicated improvement of replication probability by using multilocus genetic analyses. ]

Clinical Neuroscience

Pazopanib induced unilateral posterior reversible encephalopathy syndrome

ARSLAN Beyza Muhsine, BAJRAMI Arsida, DEMIR Elif, CABALAR Murat, YAYLA Vildan

Posterior reversible encephalopathy syndrome (PRES) is a reversible clinical and neuroradiological syndrome which may appear at any age and characterized by headache, altered consciousness, seizures, and cortical blindness. The exact incidence is still unknown. The most commonly identified causes include hypertensive encephalopathy, eclampsia, and some cytotoxic drugs. Vasogenic edema related subcortical white matter lesions, hyperintense on T2A and FLAIR sequences, in a relatively symmetrical pattern especially in the occipital and parietal lobes can be detected on cranial MR imaging. These findings tend to resolve partially or completely with early diagnosis and appropriate treatment. Here in, we present a rare case of unilateral PRES developed following the treatment with pazopanib, a testicular tumor vascular endothelial growth factor (VEGF) inhibitory agent.

Clinical Neuroscience

[Relationship between sport and traumatic brain injury - risks and sequelaes]

TAMÁS Viktória, KOVÁCS Noémi, BÜKI András

[Traumatic brain injury represents major public health problem worldwide. A typical form of brain injuries is the injury suffered during sports, which according to severity ranges from mild injuries to fatal damages. The significance of the sport related minor head injuries derives form the high incidence, the excessive involvement of the younger age groups, and their potential repetitive nature. The repeated mild head injuries may accumulate, leading to complex structural, neurochemical, neuroendocrine, and psychological alterations, which in long term may result in changes of the patients quality of life and in significant deterioration of participation in the everyday activity. Actually we neither have enough knowledge about the ne-gative consequences, nor the way of prevention, or protection against the harmful long term results. With this study summary we would like to draw attention to the potential hazards emerging from sport injuries, moreover we would like to emphasize the importance of study participation and follow up of articles in this field.]

All articles in the issue

Related contents

Clinical Neuroscience

A case with reversible neurotoxicity induced by metronidazole

EREN Fulya, ALDAN Ali Mehmet, DOGAN Burcu Vasfiye, GUL Gunay, SELCUK Hatem Hakan, SOYSAL Aysun

Background - Metronidazole is a synthetic antibiotic, which has been commonly used for protozoal and anaerobic infections. It rarely causes dose - and duration - unrelated reversible neurotoxicity. It can induce hyperintense T2/FLAIR MRI lesions in several areas of the brain. Although the clinical status is catastrophic, it is completely reversible after discontinuation of the medicine. Case report - 36-year-old female patient who had recent brain abscess history was under treatment of metronidazole for 40 days. She admitted to Emergency Department with newly onset myalgia, nausea, vomiting, blurred vision and cerebellar signs. She had nystagmus in all directions of gaze, ataxia and incompetence in tandem walk. Bilateral hyperintense lesions in splenium of corpus callosum, mesencephalon and dentate nuclei were detected in T2/FLAIR MRI. Although lumbar puncture analysis was normal, her lesions were thought to be related to activation of the brain abscess and metronidazole was started to be given by intravenous way instead of oral. As lesions got bigger and clinical status got worse, metronidazole was stopped. After discontinuation of metronidazole, we detected a dramatic improvement in patient’s clinical status and MRI lesions reduced. Conclusion - Although metronidazole induced neurotoxicity is a very rare complication of the treatment, clinicians should be aware of this entity because its adverse effects are completely reversible after discontinuation of the treatment.

Clinical Neuroscience

[Calcium ion is a common denominator in the pathophysiological processes of amyotrophic lateral sclerosis]

PATAI Roland, NÓGRÁDI Bernát, MESZLÉNYI Valéria, OBÁL Izabella, ENGELHARDT József István, SIKLÓS László

[Amyotrophic lateral sclerosis (ALS), the most frequent motor neuron disease is characterized by progressive muscle weakness caused by the degeneration of the motor neurons in the spinal cord and motor cortex. However, according to the recent observations, ALS is a rather complex syndrome which frequently involves symptoms of cognitive impairment. Therefore, ALS cases can be interpreted in a clinico-pathological spectrum spanning from the classical ALS involving only the motor system to the fronto-temporal dementia. The progression of the disease, however, manifested in the degeneration of the upper and lower motor neurons, is based on the same complex pathobiology. The main elements of the pathomechanism, such as oxidative stress, excitotoxicity, immune/inflammatory processes and mitochondrial dysfunction are well described already, which operate in orchestrated way and amplify the deleterious effect of each other. It is assumed that calcium ions act as a catalyst in this interaction, hence each of the individual mechanisms has strong, positive and reciprocal calcium dependence thus may combine the individual pathological processes into a unified escalating mechanism of neuronal destruction. This review provides an overview of the role of calcium in connecting and amplifying the major mechanisms which lead to degeneration of the motor neurons in ALS. ]

Clinical Neuroscience


VUTSKITS László, GASCON Eduardo, KISS Zoltán József

[Ketamine is a widely used drug in pediatric anesthesia practice, acting primarily through the blockade of the Nmethyl- D-aspartate (NMDA) type of glutamate receptors. A growing body of laboratory evidence, accumulated during the past few years, suggests that this drug could have potential adverse effects on the developing central nervous system. The goal of this short review is to give a brief synopsis of experimental work indicating ketamine-induced developmental neurotoxicity as well as to discuss potential limitations concerning extrapolation of these studies to clinical practice.]

Hypertension and nephrology

[Incorporation of ortho- and meta-tyrosine into cellular proteins leads to erythropoietin-resistance]

MIKOLÁS Esztella Zsóka, KUN Szilárd, LACZY Boglárka, MOLNÁR Gergő Attila, SÉLLEY Eszter, KŐSZEGI Tamás, WITTMANN István

[Introduction: Erythropoietin (EPO) is a glycoprotein hormone, which is responsible for the proliferation and differentiation of erythroid cell lines. Since it is widely used as the treatment of renal anaemia, EPO-resistance is a common concern. Aims: We aimed to perform in vitro experiments to investigate a possible mechanism of EPO-hyporesponsiveness. Methods: We used a factor dependent erythroblast cell line (TF-1). Two independent observers calculated cell counts simultaneously on day 1; 2 and 3 in Bürker cell counting chambers. Colorimetric method was used to measure protein concentrations. Measurement of protein-bound para-, ortho- and meta-tyrosine was performed with reverse phase high performance liquid chromatography with fluorescence detection. We determined ERK and STAT5 activation using Western blot method. Results: In case of ortho- and meta-tyrosine pretreated cells time-dependent, EPOinduced proliferative activity was decreased compared to the 1.7 fold elevation of cell counts seen in para-tyrosine cultured cells. Protein concentration of ortho- and metatyrosine treated samples was significantly lower than control cells on the third day. Addition of para-tyrosine reclaimed EPO-sensitivity. Erythroblasts treated with orthoor meta-tyrosine contained lower concentrations of protein-bound para-tyrosine with higher ortho- and meta-tyrosine content. EPO dependent activation of ERK and STAT5 could be inhibited by ortho- or meta-tyrosine treatment. Conclusions: Elevated level of protein-bound ortho- and meta-tyrosine in erythroblasts can result in the pathological modification of intracellular signaling, leading to EPOhyporesponsiveness.]

Lege Artis Medicinae

[Systemic diseases in pseudoexfoliation syndrome]


[Pseudoexfoliation syndrome is a condition associated with the production and accumulation of a pathological protein (pseudoexfoliation material). Originally, the syndrome was recognised on the basis of its intraocular symptoms and had been considered to be an isolated eye disease for a long time. However, some 20 years ago it became clear that in pseudoexfoliation syndrome pseudoexfoliation material is present all over in the body. In the past decade, vascular dysfunction associated with this syndrome has been also recognised. Recent studies have shown that pseudoexfoliation syndrome is caused by genetic alterations affecting a lysil oxidaselike (LOXL) protein, LOXL1. LOXL1 has an important role in the synthesis of extracellular material. To our current knowledge, pseudoexfoliation syndrome is a systemic elastosis associated with oxidative stress. Its complications are in part ocular (development of nuclear cataract, zonular damage and development of pseudoexfoliative glaucoma) and in part systemic (dysfunction of capillaries, muscular and elastic arteries, impairment of baroreflex function, increase of arterial rigidity, development of aorta aneurism, recurrent venous occlusions and neurosensory hearing loss). Despite the recognition of the above complications, currently it is not possible to set guidelines of a potential cardiovascular screening for patients with pseudoexfoliation syndrome, since the frequency and significance of systemic complications vary across different populations.]