Toxicity and teratogenicity effects of valproic acid on zebrafish (Danio rerio) embryos in relation to autism spectrum disorder

Valproic acid (VPA) is a widely prescribed antiepileptic drug with various medicinal efficacies. Accumulated evidence implied that prenatal exposure to VPA is highly associated with autism spectrum disorder (ASD). In this study, the zebrafish were exposed to a set of VPA concentrations (0, 5, 10, 20, 40, 80, 160, 320, 640, 1280, and 2560 μM) at 5 h post fertilization (hpf) to 120 hpf. The adverse effects of VPA were extensively studied through the evaluations on the mortality, heartbeats, spontaneous tail coiling, and hatching rate. Morphological observations were conducted at 120 hpf, following the exposure termination. Basic locomotor responses and anxiety-like behavioral alterations evaluated for behavioral impairments are the hallmark feature of ASD. The exposure to VPA at teratogenic concentrations reduced the aforementioned parameters in a dose-dependent manner (p ≤ .05). At the selected non-teratogenic concentrations of VPA, the treated larvae demonstrated profound alterations of basic locomotor responses. No significant changes of anxiety and thigmotactic behaviors were observed on the VPA-treated fish compared to the control (p ≥ .005). This study depicted that embryonic zebrafish exposure to VPA produced significant toxicity and teratogenicity effects as well as the alterations of basic behavioral responses. Overall, this study provides a fundamental insight of the toxicity effects at morphological and behavioral levels to facilitate the understanding of ASD mechanisms at different molecular levels.

Embryonic mercury exposure in zebrafish: Alteration of metabolites and gene expression, related to visual and behavioral impairments

The widespread presence of mercury, a heavy metal found in the environment and used in numerous industries and domestic, raises concerns about its potential impact on human health. Nevertheless, the adverse effects of this environmental toxicant at low concentrations are often underestimated. There are emerging studies showing that accumulation of mercury in the eye may contribute to visual impairment and a comorbidity between autism spectrum disorders (ASD) trait and visual impairment. However, the underlying mechanism of visual impairment in humans and rodents is challenging. In response to this issue, zebrafish larvae with a cone-dominated retinal visual system were exposed to 100 nM mercury chloride (HgCl₂), according to our previous study, followed by light-dark stimulation, a social assay, and color preference to examine the functionality of the visual system in relation to ASD-like behavior. Exposure of embryos to HgCl₂ from gastrulation to hatching increased locomotor activity in the dark, reduced shoaling and exploratory behavior, and impaired color preference. Defects in microridges as the first barrier may serve as primary tools for HgCl₂ toxicity affecting vision. Depletion of polyunsaturated fatty acids (PUFAs), linoleic acid, arachidonic acid (ARA), alpha-linoleic acid, docosahexaenoic acid (DHA), stearic acid, L-phenylalanine, isoleucine, L-lysine, and N-acetylputrescine, along with the increase of gamma-aminobutyric acid (GABA), sphingosine-1-phosphate, and citrulline assayed by liquid chromatography-mass spectrometry (LC-MS) suggest that these metabolites serve as biomarkers of retinal impairments that affect vision and behavior. Although suppression of adsl, shank3a, tsc1b, and nrxn1a gene expression was observed, among these tsc1b showed more positive correlation with ASD. Collectively, these results contribute new insights into the possible mechanism of mercury toxicity give rise to visual, cognitive, and social deficits in zebrafish.

Embryonic Arsenic Exposure Triggers Long-Term Behavioral Impairment with Metabolite Alterations in Zebrafish

Arsenic trioxide (As₂O₃) is a ubiquitous heavy metal in the environment. Exposure to this toxin at low concentrations is unremarkable in developing organisms. Nevertheless, understanding the underlying mechanism of its long-term adverse effects remains a challenge. In this study, embryos were initially exposed to As₂O₃ from gastrulation to hatching under semi-static conditions. Results showed dose-dependent increased mortality, with exposure to 30-40 µM As₂O₃ significantly reducing tail-coiling and heart rate at early larval stages. Surviving larvae after 30 µM As₂O₃ exposure showed deficits in motor behavior without impairment of anxiety-like responses at 6 dpf and a slight impairment in color preference behavior at 11 dpf, which was later evident in adulthood. As₂O₃ also altered locomotor function, with a loss of directional and color preference in adult zebrafish, which correlated with changes in transcriptional regulation of adsl, shank3a, and tsc1b genes. During these processes, As₂O₃ mainly induced metabolic changes in lipids, particularly arachidonic acid, docosahexaenoic acid, prostaglandin, and sphinganine-1-phosphate in the post-hatching period of zebrafish. Overall, this study provides new insight into the potential mechanism of arsenic toxicity leading to long-term learning impairment in zebrafish and may benefit future risk assessments of other environmental toxins of concern.

Mapping Molecular Networks within Clitoria ternatea Linn. against LPS-Induced Neuroinflammation in Microglial Cells, with Molecular Docking and In Vivo Toxicity Assessment in Zebrafish

Clitoria ternatea Linn. (CT), or butterfly pea, is an Ayurvedic plant traditionally used as a brain tonic. Recently, it was reported to be of use in treating central nervous system (CNS) disorders, i.e., as an antistress treatment and antidepressant. In the present study, we report a detailed phytochemical profile of the ethyl acetate fraction of the flower of CT (CTF_EA) with significant neuroprotective and anti-neuroinflammatory properties in both LPS-activated BV-2 and SK-N-SH cells. Concurrently, the molecular network (MN) derived from the CTF_EA metabolome allows putative identification of flavonol 3-O-glycosides, hydrocinnamic acids, and primary metabolites. Molecular docking studies suggest that CTF_EA preferentially targets iNOS, resulting in a decrease in nitric oxide (NO). Furthermore, no toxic effects on normal embryonic development, blood vessel formation, and apoptosis are observed when CTF_EA is tested for in vivo toxicity in zebrafish models. The overall preliminary results suggest the anti-neuroinflammatory and neuroprotective effects of CT and provide scientific support for the efficacy of this medicinal plant at local and traditional levels. However, studies on the targeted isolation of bioactive metabolites, in-depth pharmacological efficacy, and safety in mammalian models are urgently needed to expand our understanding of this plant before it is developed into a promising therapeutic agent for brain-related diseases.

Evaluation of Salivary Leptin Levels and Its Correlation with Class I, Class II, and Class III Facial Skeletal Pattern: A Prefatory Study

Objective The aim of this study was to assess and compare the salivary leptin hormone levels between different classes of facial skeletal pattern (Class I, II, and III).

Materials and Methods A sample of 62 patients were selected prior to the orthodontic treatment from a population that attended the International Islamic University Malaysia Specialist Orthodontic Clinic. Based on the lateral cephalometric analysis, the subjects were grouped into Class I, Class II, and Class III facial skeletal patterns, according to Eastman and Wits appraisal. Subsequently, unstimulated saliva samples were taken and purified to undergo leptin enzyme-linked immunosorbent assay analysis to determine the levels of leptin hormone. Statistical analysis using the Kruskal–Wallis test was used to analyze the data obtained.

Results The results showed that there was a significant difference between the levels of leptin hormone between Class I and Class II skeletal patterns and between Class I and Class III facial skeletal patterns. No statistical difference was noted between the levels of leptin of Class II and Class III facial skeletal patterns.

Conclusion Salivary leptin hormone levels are higher in patients with Class II and Class III facial skeletal patterns compared with Class I.

Perturbations in Amino Acid Metabolism in Reserpine-Treated Zebrafish Brain Detected by 1H Nuclear Magnetic Resonance-Based Metabolomics

Depression is a complex and disabling psychiatric disorder, which is expected to be a leading cause for disability by 2030. According to World Health Organization, about 350 million people are suffering with mental health disorders around the globe, especially depression. However, the mechanisms involved in stress-induced depression have not been fully elucidated. In this study, a stress-like state was pharmacologically induced in zebrafish using reserpine, a drug widely used to mediate depression in experimental animal models. Zebrafish received single intraperitoneal (i.p.) injections of 20, 40, and 80 mg/kg body weight reserpine doses and were subjected to open-field test at 2, 24, 48, 72, and 96 h after the treatment. Along with observed changes in behavior and measurement of cortisol levels, the fish were further examined for perturbations in their brain metabolites by ¹H nuclear magnetic resonance (NMR)-based metabolomics. We found a significant increase in freezing duration, whereas total distance travelled was decreased 24 h after single intraperitoneal injection of reserpine. Cortisol level was also found to be higher after 48 h of reserpine treatment. The ¹H NMR data showed that the levels of metabolites such as glutamate, glutamine, histamine, valine, leucine and histidine, lactate, l-fucose, betaine and γ-amino butyric acid (GABA), β-hydroxyisovalerate, and glutathione were significantly decreased in the reserpine-treated group. This study provided some insights into the molecular nature of stress that could contribute toward a better understanding of depression disorder.

Does facial appearance of dentofacial deformity influence the need for orthognathic surgery: The Malaysian perception

Aim: This study evaluates perception toward facial appearance in dentofacial deformity and the need for orthognathic surgery among the public with and without dental backgrounds. Materials and Methods: A questionnaire consisting of 12 facial photographs of cases with dentofacial deformity or malocclusion in varying severity was used. A hundred individuals were selected to answer the questionnaire. The perception of facial appearance (FAS), treatment need score (TNS), and knowledge regarding dentofacial deformity were used for the evaluation. Results: Significant differences were found between dental and non-dental when the respondents' knowledge in all the questionnaire items ([Formula: see text].05) was assessed. However, no significant difference was found in the mean of FAS and TNS in all the presented cases (normal, borderline, severe). Pearson correlation between perceived FAS and TNS was statistically negative for severe and normal cases, whereby a decrease in FAS for severe cases showed an increase in TNS, and an increase in FAS for normal cases showed a decrease in TNS. Conclusion: Respondents with dental background had sound knowledge of dentofacial deformity. A poorly attractive respondent with dentofacial deformity showed a greater need for orthognathic surgery.

Assessment of Dental Development in Children with Hypodontia and Hyperdontia: A Case Control Study

The aim is to investigate the dental development (DD) in children with hypodontia and hyperdontia compared to age, gender, and race matched controls.A match-pair case control study was conducted among children aged 5 to 14-year-old, attending the Dental Polyclinic, IIUM, from December 2011 until September 2014. Willem’s method was used to analyze the dental age (DA) using panoramic radiograph. The difference between dental age of hypodontia/hyperdontia children and the controlswas analyzed using analysis of covariance (ANCOVA). The differences between dental and chronological ages (CA) and the differences in DA and CA with the numbers of missing teeth were analyzed using t-test. Intra-class correlation coefficient between examiners ranged from 0.98-0.99. The result is that27 hypodontia and 12 hyperdontia samples were recruited and compared to a total of 78 matched controls. Both male (n=12) and female (n=15) hypodontia children had statistically significant delay in DD (p=0.000). There was no significant difference in the DD of male (n=7, p=0.811) and female (n=5, p=0.235) in hyperdontia children compared to the matched controls. No differences were observed between DA and CA with the number of missing teeth. Unlike hyperdontia children, hypodontia children showed delayed DD in comparison to age, gender, and race matched controls. There was no association between magnitudes of dental development delay in hypodontia children with the number of missing teeth. This study provides valuable baseline information for provision of better treatment planning for those hypodontia and hyperdontia children that may involve inter-disciplinary management.

Latent Class Analysis of Dental Treatment: Observed in IIUM Dental Specialist Clinic, Kuantan, Pahang

Research into dental treatment via statistical perspective was unraveled through a relation between theoretical and experimental probability. This assessment of association was examined using statistical test over Confirmatory Factor Analysis (CFA) and Latent Class Analysis (LCA). Theoretical results of the prevailing difference between the direct and indirect upshot was verified through a technique known as integrated model by using Mplus® software package. The results expressively show that the dental treatment from the indirect effect has better performance than the direct effect. Besides that, there is a dramatic improvement of dental treatment from different type of malocclusion analysis. Three classes of different type of malocclusion analysis play an important role as mediator for demographic variable and type of dental treatment.

Saliva Leptin Levels in Tooth Movement during Initial Stage of Orthodontic Alignment: A Pilot Study

Introduction: During orthodontic tooth movement, the early response of periodontal tissues to mechanical stress is an acute inflammatory reaction. Mechanical stress from orthodontic appliances is believed to induce cells in the periodontal ligament (PDL) to form biologically active substances, such as enzymes and cytokines, responsible for connective tissue remodeling (Nishijima Y et al 2006). Leptin, a polypeptide hormone has been classified as a cytokine (Zhang et al 1994). Earlier findings concluded that leptin at high local concentrations protects the host from inflammation and infection as well as maintaining bone levels. It has been also suggested that leptin plays a significant role in bone formation by its direct effect on osteoblasts (Alparslan et al 2010). This pilot study aimed to study leptin in saliva and its association with tooth movement during initial orthodontic alignment. Objectives: To determine if there are any differences in saliva leptin level before and after orthodontic alignment. Material and methods: Ten orthodontic patients (7 girls and 3 boys; mean age, 16.76 ± 1.1 years) with crowding (up to 5mm) that required orthodontic fixed appliances, on a non-extraction basis as part of the treatment plan, were recruited in this longitudinal study. Orthodontic study models were constructed at baseline and at 6- weeks after orthodontic treatment commenced. Full fixed orthodontic appliances with initial 0.014” Nickel Titanium archwire placed. The amount of crowding was measured, before and after initial alignment with an electronic digital caliper (Max-Cal, Japan Micrometer Ltd, Tokyo, Japan) with an accuracy of up to 0.01mm. Unstimulated morning saliva sample were collected at all visits, after at least an 8-hour period of fasting and no-toothbrushing. After centrifugation (4000x g;10min), the samples were stored at -25C and tested using Leptin Abnova LEP Human ELISA kit (KA3080) which was subsequently analyzed. Subjects’ periodontal health status was also monitored throughout the study. Ethical approval (ID IREC 262) was received on 7th April 2014 from International Islamic University Malaysia Research Ethics Committee (IREC). Results: Leptin concentration in saliva was significantly decreased in a time-dependant manner (t(9)=8.60, p<0.001), from before orthodontic treatment (7016.45± 425.15 pg/mL) and 6 weeks after bond-up (4901.92±  238.64 pg/mL). Conclusion: Leptin concentration in saliva is decreased during orthodontic tooth movement in initial alignment stage.

Identification Of PAX9 Single Nucleotide Polymorphism In Class III Malocclusion Patients With Mandibular Prognatism

Introduction: PAX9 (Paired box 9) gene is one of the genes which play significant role during craniofacial development. Single nucleotide polymorphism (SNP) in PAX9 has been associated with Class II/Division 2 malocclusion (with or without hypodontia). However, the relationship between PAX9 SNP marker (rs8004560) with mandibular prognathism (MP) has not been analysed, at least in our local population. This study aimed to detect the presence of PAX9 (rs8004560) SNP in Class III malocclusion patients (with MP) in the local population. Materials and Methods: Genomic DNA were extracted from unstimulated saliva of 31 class I malocclusion (control samples) and 30 patients from Class III malocclusion (MP). Cephalometric measurements were performed prior to saliva samples collection. The DNA was amplified using the specific primers for the marker rs8004560 and the genotyping was done by sequencing. Chi-square test was used to determine the overrepresentation of marker allele (p<0.05). Results:  Presence of PAX9 SNP (rs8004560) was detected in local population analysed and the distribution of its genotype and allele could be observed. There were significant differences between allele (p=0.000) and genotype (p=0.000) frequency within control (Class I) and Class III malocclusion. Conclusion(s): The most common allele of a marker flanking PAX9 (rs8004560) was over-represented in the mandibular prognathism (MP) subjects indicating the genetic association of PAX9 (rs8004560) SNP in the incidence of MP. Further studies involving larger number of samples should be developed in order to understand the exact role and mechanism of PAX9 in different classes of malocclusions.

Analysis Of MYO1H Single Nucleotide Polymorphism In Class III Malocclusion With Mandibular Prognathism: A Preliminary Study

Introduction: Evidence suggests that several genes; including MYO1H, play an important role in the etiology of Class III malocclusion. Single nucleotide polymorphism (SNP) in marker rs10850110 (locus 12q24.11) within MYO1H gene has been associated with the incidence of mandibular prognathism (MP). MYO is a class 1 myosin that is responsible for the synthesis of Matrilin-1; an important protein involved in the formation of cartilage's extracellular matrix, hence is implicated in the formation of mandibular condyle cartilage. This study aimed to detect the presence of MYO1H (rs10850110) SNP and to determine its genotype and allele distribution in MP patient in the local population. Materials and Methods: The sample comprises of 31 patients; 14 patients from class I malocclusion (control samples) and 17 patients from class III malocclusion (MP). Cephalometric measurements were performed prior to saliva samples collection. The DNA was amplified using the specific primers for the marker rs10850110 and the genotyping was done by sequencing. Chi-square test was used to determine the over-representation of marker allele (p<0.05). Results:  Presence of MYO1H SNP (rs10850110) was detected in local population analysed and the distribution of its genotype and allele could be observed. There were significant differences between allele (p=0.000) and genotype (p=0.000) frequency within control (Class I) and Class III malocclusion. Conclusion(s):  Our findings are in agreement with previous studies suggesting positive influence of MYO1H (rs10850110) SNP in the incidence of MP. Further studies should be developed in order to understand the exact role and mechanism of MYO1H in different classes of malocclusions.

Standard Versus Real Versus Fake Braces: An Elemental Composition Analysis

Introduction: Orthodontic fixed appliance is now considered as fashion accessory and a symbol of wealth. Due to overwhelming demand, 'fake' and 'real' braces services have been offered through social media by unqualified personnel using poor quality orthodontic brackets and cases of metal toxicity from using these type of braces has been reported. Materials and Methods: This study was conducted to explore the elemental analysis of several types of 'fake', 'real' and standard braces. The metal composition of 9 upper right central incisor brackets were measured using high pressure environmental scanning electron microscope equipped with an energy dispersive X-ray spectrometer (ESEM/EDX). The quantitative analysis of the percentage of weight concentration of the elements were calculated. Results: The elemental analysis using ANOVA revealed that there was no statistically difference metal weight composition between 'fake', 'real' and standard braces. All brackets were manufactured from different types of alloys. Nonetheless, no toxic elements such as plumbum or mercury were detected in the composition of 'fake' and 'real' braces. Conclusion(s): In conclusion, the metal compositions of 'fake' and 'real' braces were not statistically different from conventional brackets and no pernicious elements were detected.

Standard Versus Real Versus Fake Braces: Design And Microstructure Comparison

Introduction: The growing demand for orthodontic braces among Malaysian community has led to the development of "fake" and "real" braces. "Fake" braces refer to braces that are worn as costume and are not bonded to teeth hence unable to produce movement of teeth. "Real" braces refer to braces that are bonded to tooth structure and are able to produce tooth movement. The braces are bonded by unqualified practitioners with no formal dental education and they provide braces treatment in unlicensed premises such as hotel rooms or patients' own homes. Materials and Methods: This study was conducted to investigate the design and microstructure of several types of "fake", "real" and standard braces. A total of 9 upper right central incisor brackets were scanned using high resolution scanning electron microscopy (SEM) with magnifications of 65x, 500x and 1000x. Brackets slot heights and depths were also measured to compare slot dimensions between "fake", "real" and standard braces. Results: The surface textures of "fake" and "real" braces were noticeably more granular and unpolished as compared to conventional brackets. Furthermore, all "fake" and some "real" braces upper right central incisor bracket designs were distinctly different from the standard braces. The slot dimensions of "fake" and "real" braces were also significantly larger that standard braces. Conclusion(s): In conclusion, the surface texture and morphology of "fake" and "real" braces were crude and different when compared to conventional brackets.

Determination Of RUNX2 Single Nucleotide Polymorphism rs6930053 In Class I, II And III Malocclusions

Introduction: Runt-related transcription factor 2 (RUNX2) plays important roles in osteoblast differentiation, tooth development and chondrocyte maturation; hence its involvement in craniofacial development is paramount. Mutation in RUNX2 is implicated with cleidocranial dysplasia; a bone development disorder, while single nucleotide polymorphism (SNP) in RUNX2 is associated with Class II/2 malocclusion. This study aimed to determine RUNX2 SNP of DNA marker (rs6930053) in malocclusion patients from local population. Materials and Methods: Genomic DNA were extracted from unstimulated saliva of 31 Class I (control samples), 30 Class II and 30 Class III malocclusion patients. Cephalometric measurements were performed prior to saliva samples collection. The DNA was amplified using the specific primers for marker rs6930053 and the genotyping was done by sequencing. Chi-square test was used to determine differences in allele and genotype frequencies (p<0.05). Results:  No significant differences were observed in RUNX2 SNP (rs8004560) in Class I and Class III malocclusion. However, there were significant differences between allele (p=0.000) and genotype (p=0.000) frequency within Class II alone; while significant differences was detected only in allele frequency between control and Class II malocclusion (p=0.019). Conclusion(s):  There is genetic association between RUNX2 (rs6930053) in Class II malocclusion in our population. Further studies involving larger number of samples and other DNA markers of RUNX2 gene should be developed in order to understand the exact role and mechanism of RUNX2 in different classes of malocclusions. 

Development of an inhibitive enzyme assay for copper

In this work the development of an inhibitive assay for copper using the molybdenum-reducing enzyme assay is presented. The enzyme is assayed using 12-molybdophosphoric acid at pH 5.0 as an electron acceptor substrate and NADH as the electron donor substrate. The enzyme converts the yellowish solution into a deep blue solution. The assay is based on the ability of copper to inhibit the molybdenum-reducing enzyme from the molybdate-reducing Serratia sp. Strain DRY5. Other heavy metals tested did not inhibit the enzyme at 10 mg l(-1). The best model with high regression coefficient to measure copper inhibition is one-phase binding. The calculated IC50 (concentration causing 50% inhibition) is 0.099 mg l(-1) and the regression coefficient is 0.98. The comparative LC50, EC50 and IC50 data for copper in different toxicity tests show that the IC50 value for copper in this study is lower than those for immobilized urease, bromelain, Rainbow trout, R. meliloti, Baker's Yeast dehydrogenase activity Spirillum volutans, P. fluorescens, Aeromonas hydrophilia and synthetic activated sludge assays. However the IC50 value is higher than those for Ulva pertusa and papain assays, but within the reported range for Daphnia magna and Microtox assays.