Corrigendum to "N-Acetyl Cysteine as a Novel Polymethyl Methacrylate Resin Component: Protection against Cell Apoptosis and Genotoxicity".

[This corrects the article DOI: 10.1155/2019/1301736.].

N-Acetyl Cysteine as a Novel Polymethyl Methacrylate Resin Component: Protection against Cell Apoptosis and Genotoxicity.

The present study investigated the antiapoptotic and antigenotoxic capabilities of N-acetyl cysteine- (NAC-) containing polymethyl methacrylate (PMMA) resin. An in vitro Transwell insert model was used to mimic the clinical provisional restorations placed on vital teeth. Various parameters associated with cell apoptosis and genotoxicity were investigated to obtain a deeper insight into the underlying mechanisms. The exposure of human dental pulp cell (hDPC) cultures to the PMMA resin (Unifast Trad™) resulted in a rapid increase in reactive oxygen species (ROS) level beginning at 1 h, which was followed by time-dependent cell detachment and overt death. The formation of γ-H2AX and cell cycle G1 phase arrest indicated that oxidative DNA damage occurred as a result of the interactions between DNA bases and ROS, beyond the capacities of cellular redox regulation. Such oxidative DNA damage triggers the activation of p53 via the ataxia telangiectasia mutated (ATM) signaling pathway and the induction of intrinsic mitochondrial apoptosis. Oxidative stress, cell apoptosis, and DNA damage induced by the PMMA resin were recovered to almost the level of untreated controls by the incorporation of NAC. The results indicate that the PMMA resin induced the intrinsic mitochondrial apoptosis as a consequence of p53 activation via the ATM pathway in response to oxidative DNA damage. More importantly, the incorporation of NAC as a novel component into the Unifast Trad™ PMMA resin offers protective effects against cell apoptosis and genotoxicity. This procedure represents a beneficial strategy for developing more biocompatible PMMA-based resin materials.

Rational search for genes in familial cortical myoclonic tremor with epilepsy, clues from recent advances.

Familial cortical myoclonic tremor with epilepsy (FCMTE) is an autosomal dominant epilepsy syndrome with considerable clinical and genetic heterogeneity. The most important clinical manifestations include adult onset, cortical myoclonic tremor, with or without epileptic seizures. Of the four loci reported, which included 8q24 (FCMTE1), 2p11.1-q12.2 (FCMTE2), 5p15.31-p15.1 (FCMTE3), and 3q26.32-3q28 (FCMTE4), only one probably causative mutation was found co-segregated in two FCMTE2 pedigrees in the α2-adrenergic receptor subtype B (ADRA2B) gene. In this review we discuss studies that focused on the molecular genetics of FCMTE, its neuropathology, clinical, neurophysiological and neuroimaging features, which may offer useful clues for the search for causative FCMTE genes. Next-generation sequencing has identified many causative genes in monogenic diseases. However, most next-generation sequencing applications focus on detecting single nucleotide variants or small insertions/deletions, which do not completely resolve the challenge of identifying causative genes in FCMTE. Recent progress in exploring FCMTE has revealed that special mutations such as copy number variants, exon rearrangements and large trinucleotide repeat expansion (or polynucleotide repeat expansion) should be considered. Clues from neuropathological, clinical, neurophysiological and neuroimaging studies indicate that the candidate causative genes should be expressed in the cerebellum, especially in Purkinje cells, and be associated with calcium signaling and GABA receptors. We propose that the developing novel algorithms of next-generation sequencing data, which could detect structure variants and candidate causative gene selection when combined with special mutations detection analysis represent possible future direction of a rational search for causative genes in FCMTE.

Fine mapping and whole-exome sequencing of a familial cortical myoclonic tremor with epilepsy family.

Familial cortical myoclonic tremor with epilepsy (FCMTE) is an autosomal dominant epilepsy syndrome. Four loci, including 8q24 (FCMTE1), 2p11.1-q12.2 (FCMTE2), 5p15.31-p15.1 (FCMTE3), and 3q26.32-3q28 (FCMTE4) were previously reported. Herein, we report a new FCMTE1 pedigree from Chinese population with its clinical and genetic study results. Whole genome scan was performed to identify the causative gene region and copy number variants. Whole-exome sequencing was used to identify the causative gene. There were twelve affected members alive in this FCMTE1 pedigree. Nine affected members had both cortical myoclonic tremor and epilepsy, while three affected members had only cortical myoclonic tremor. Electrophysiologic examinations manifested giant somatosensory evoked potentials and long-latency cortical reflex in some affected members. Whole genome scan identified a 20.4 Mb causative gene region at 8q22.3-q24.13. No copy number variants were identified as the causative mutation. Whole-exome sequencing identified a co-segregated mutation (c.206A>T; p.Y69F) in the SLC30A8 gene. However, the evidence supporting this gene as the causative gene of FCMTE1 is not enough. We report the first Chinese FCMTE1 pedigree. No copy number variants, point mutation or small insertion/deletion were detected in the identified region that showed an association with FCMTE1. Further studies could focus on other possible genetic mechanisms while the association between the SLC30A8 and FCMTE1 needs further evidence.

N-n-butyl haloperidol iodide preserves cardiomyocyte calcium homeostasis during hypoxia/ischemia.

AIMS: N-n-Butyl haloperidol iodide (F(2)) is a novel compound derived from haloperidol. In our previous work, F(2) was found to be an L-type calcium channel blocker which played a protective role in rat heart ischemic-reperfusion injury in a dose-dependent manner. In the current study, we aimed to investigate the effects and some possible mechanisms of F(2) on calcium transients in hypoxic/ischemic rat cardiac myocytes. METHODS AND RESULTS: Calcium transients' images of rat cardiac myocytes were recorded during simulated hypoxia, using a confocal calcium imaging system. The amplitude, rising time from 25% to 75% (RT25-75), decay time from 75% to 25% (DT75-25) of calcium transients, and resting [Ca(2+)](i) were extracted from the images by self-coding programs. In this study, hypoxia produced a substantial increase in diastolic [Ca(2+)](i) and reduced the amplitude of calcium transients. Both RT25-75 and DT75-25 of Ca(2+) transients were significantly prolonged. And F(2) could reduce the increase in resting [Ca(2+)](i)and the prolongation of RT25-75 and DT75-25 of Ca(2+) transients during hypoxia. F(2) also inhibited the reduction in amplitude of calcium transients which was caused by 30-min hypoxia. The activity of SERCA2a (sarcoplasmic reticulum Ca(2+)-ATPase, determined by test kits) decreased after 30-min ischemia, and intravenous F(2) in rats could ameliorate the decreased activity of SERCA2a. The inward and outward currents of NCX (recorded by whole-cell patch-clamp analysis) were reduced during 10-min hypoxia, and F(2) further inhibited the outward currents of NCX during 10-min hypoxia. All these data of SERCA2a and NCX might be responsible for the changes in calcium transients during hypoxia. CONCLUSION: Our data suggest that F(2) reduced changes in calcium transients that caused by hypoxia/ischemia, which was regarded to be a protective role in calcium homeostasis of ventricular myocytes, probably via changing the function of SERCA2a.

The behaviour of neural stem cells on polyhydroxyalkanoate nanofiber scaffolds.

Polyhydroxyalkanoates (PHA) have demonstrated their potentials as medical implant biomaterials. Neural stem cells (NSCs) grown on/in PHA scaffolds may be useful for repairing central nervous system (CNS) injury. To investigate this possibility, nanofiber matrices (scaffolds) prepared from several PHA via a novel phase separation process were studied to mimic natural extracellular matrix (ECM), and rat-derived NSCs grown in the PHA matrices were characterized regarding their in vitro differentiation behaviors. All three PHA materials including poly(3-hydroxybutyrate) (PHB), copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate (P3HB4HB), and copolymer of 3-hydroxybutyrate and 3-hydroxyhexanoate (PHBHHx) supported NSC growth and differentiation both on their 2D films and 3D matrices. Among three PHA nanofiber matrices, PHBHHx one showed the strongest potentials to promote NSC differentiation into neurons which is beneficial for CNS repair. Compared to the 2D films, 3D nanofiber matrices appeared to be more suitable for NSC attachment, synaptic outgrowth and synaptogenesis. It was suggested that PHBHHx nanofiber scaffolds (matrices) that promote NSC growth and differentiation, can be developed for treating central nervous system injury.

Differentiation of human bone marrow mesenchymal stem cells grown in terpolyesters of 3-hydroxyalkanoates scaffolds into nerve cells.

Polyhydroxyalkanoates, abbreviated as PHA, have been studied for medical applications due to their suitable mechanical properties, blood and tissue tolerance and in vivo biodegradability. As a new member of PHA family, terpolyester of 3-hydroxybutyrate, 3-hydroxyvalerate and 3-hydroxyhexanoate, abbreviated as PHBVHHx, was compared with polylactic acid (PLA), copolyester of 3-hydroxybutyrate and 3-hydroxyhexanoate (PHBHHx) for their respective functions leading to differentiation of human bone marrow mesenchymal stem cell (hBMSC) into nerve cells. Results indicated that 3D scaffolds promoted the differentiation of hBMSC into nerve cells more intensively compared with 2D films. Smaller pore sizes of scaffolds increased differentiation of hBMSC into nerve cells, whereas decreased cell proliferation. PHBVHHx scaffolds with pore sizes of 30-60 microm could be used in nerve tissue engineering for treatment of nerve injury. The above results were supported by scanning electron microscope (SEM) and confocal microscopy observation on attachment and growth of hBMSCs on PLA, PHBHHx and PHBVHHx, and by CCK-8 evaluation of cell proliferation. In addition, expressions of nerve markers nestin, GFAP and beta-III tubulin of nerve cells differentiated from hBMSC grown in PHBVHHx scaffolds were confirmed by real-time PCR.

[Fast 2-dimension scanning and line-scanning of intracellular Ca2+ transients in cardiac myocytes].

AIM: Fast 2-dimension scanning and line-scanning of confocal imaging were employed for measurement of cardiac Ca2+ transients, and the advantages and disadvantages about these two scannings were discussed. METHODS: Single adult SD rat cardiac myocytes were made freshly and loaded with fluo4-AM. Intracellular Ca2+ was imaging by the LSMS10 META system. The Ca2+ transients were evoked by electrical field stimulation from an electronic stimulator which was triggered to work synchronically with the confocal imaging system. RESULTS: Fast 2-dimension scanning showed the global Ca2+ signal clearly, which would be more helpful especially in monitoring a cell of Ca2+ overload or in other pathological conditions. And the images could be packaged into a vivid animation, which showed the process of Ca2+ transients and cell contraction visually and virtually. Line-scanning showed the Ca2+ transients in good temporal and spacial resolutions along the long axis of the cell. And the dynamic shortening of the cell length could be used for indicating the contraction of the cell. Data from line-scanning would be helpful for drawing some more exact conclusions. CONCLUSION: In general, fast 2-dimension scanning and line-scanning could work reciprocally to show a more perfect picture of the intracellular Ca2+ transients in cardiac myocytes.

[The characteristics of gene mutations in Chinese patients with Charcot-Marie-Tooth disease].

OBJECTIVE: To study the characteristics of gene mutations in Chinese patients with Charcot-Marie-Tooth disease (CMT). METHODS: Real-time quantitative PCR, PCR-SSCP, and/or direct sequencing were used to analyze the mutation of the pathogenic genes PMP22, MPZ, CX32, EGR2, GDAP1, NEFL, HSP22 and HSP27 in 113 probands of CMT families, 45 of which had family history, from different provinces in China. The whole family members of the subjects with abnormal electrophoretic bands and 50 normal controls underwent the same examination. RESULTS: Thirty-six cases of PMP22 duplication, 7 cases of CX32 mutation, 1 case of HSP22 mutation, 1 case of HSP27 mutation, 1 case of MPZ mutation, and 1 case of GDAP1 mutation were found in the 113 CMT probands. No point mutation was found in PMP22, EGR2 and NEFL genes. CONCLUSION: Among the Chinese CMT patients 31.9% are caused by PMP22 duplication, 6.2% by CX32, and 0.9% by HSP22, HSP27, MPZ and GDAP1. Point mutations of PMP22, EGR2 and NEFL are rare.

Mutation screening of Cx32 in Han Chinese patients with Charcot-Marie-Tooth disease.

OBJECTIVE: To investigate the Cx32 mutation features and the clinical manifestations of Chinese patients with Charcot-Marie-Tooth disease(CMT). METHODS: Twenty-four of 65 unrelated CMT patients were selected for Cx32 mutation screening after the exclusion of the CMT1A 1.5 Mb duplication and male-to-male transmission. The motor and sensory nerve conduction studies were performed in all probands and most of their affected family members to establish the clinical CMT1 ,CMT2 or CMT intermediate diagnosis. The presence of mutations in the coding region of Cx32 was detected by single-strand conformation polymorphism analysis combined with direct sequencing. RESULTS: We found 7 different point mutations in the coding region of Cx32 in a total of 7 families. All the patients were mildly to moderately affected with a clinical CMT1 or CMT intermediate diagnosis. The mutation Arg15Gln was inherited with X-linked recessive trait in family 1 involved in our study. The Arg75Trp mutation was detected in a family with X-linked dominant CMT and autosomal recessive nonsydromic hearing loss. The clinical phenotype of the Thr188Ala mutation was firstly reported. CONCLUSION: Seven different Cx32 point mutations were detected and the percentage of Chinese CMT families with Cx32 mutation is about 10% in our study. The inheritance model of CMT secondary to Cx32 mutation could be X-linked dominant, X-linked recessive or sporadic. Male patients are usually more severely affected than females with slower nerve conduction velocities. Cx32 mutation screening should be firstly performed in those CMT families without male-to-male transmission and CMT1A duplication.

A new locus for autosomal dominant Charcot-Marie-Tooth disease type 2 (CMT2L) maps to chromosome 12q24.

Charcot-Marie-Tooth disease (CMT) is one of the most common inherited neurological disorders with a prevalence estimated at 1/2500. The axonal form of this disorder is referred to as Charcot-Marie-Tooth type 2 disease (CMT2). Recently, a large Chinese family with CMT2 was found in the Hunan and Hubei provinces of China. The known loci for CMT1A, CMT2D, CMT1B (the same locus is also responsible for CMT2I and CMT2J), CMT2A, CMT2E, and CMT2F were excluded in this family by linkage analysis. A genome-wide screening was then carried out, and the results revealed linkage of CMT2 to a locus at chromosome 12q24. Haplotype construction and analyses localized this novel locus to a 6.8-cM interval between microsatellite markers D12S366 and D12S1611. The maximal two-point LOD score of 6.35 and multipoint LOD score of 8.08 for marker D12S76 at a recombination fraction (theta) of 0 strongly supported linkage to this locus. Thus, CMT2 neuropathy in this family represents a novel genetic entity that we have designated as CMT2L.

[Spastin gene mutation in Chinese patients with hereditary spastic paraplegia].

OBJECTIVE: To investigate the mutation characteristics of spastin gene in Chinese patients with hereditary spastic paraplegia (HSP) and thus provide a basis for the gene diagnosis of HSP. METHODS: Mutation of spastin gene was screened by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) combined with DNA direct sequencing in 31 unrelated affected HSP individuals in China, of whom 22 were from autosomal dominant families and 9 were sporadic HSP patients. Co-segregation analysis was carried out after the finding of abnormal SSCP bands. RESULTS: Six cases were found to have abnormal SCP bands, and among them, two missense mutations (T1258A, A1293G in exon 8) and one deletion mutation (1667delACT or 1668delCTA or 1669delTAC in exon 14) were found and all of them were not reported previously. They were all co-segregated with the disease and were localized within the functional domain of spastin gene. Besides, T1258A was seen in two unrelated families. CONCLUSION: The mutation rate (18.2%) in autosomal dominant HSP in Chinese patients is comparatively low. Point mutation is the major mutation type and exon 8 may be the mutation hot spot.