Melatonin and melatonergic drugs in sleep disorders.

Melatonin is an endogenous chronobiological regulator secreted mainly from the pineal gland, which has been used as a dietary supplement in the treatment of sleep problems, including insomnia, parasomnia, and circadian rhythm sleep disorders. However, the short half-life and rapid metabolism of melatonin limit its suitability as a drug. There are many melatonergic drugs used in the treatment of sleep disorders and several drugs are under investigation for approval. Ramelteon was the first melatonergic agonist approved as hypnotic agent by U.S. Food and Drug Administration for the treatment of insomnia. It exhibits higher selective affinity for melatonin 1a (MT1) receptor than melatonin 1b (MT2) receptor. This selectivity suggests that it targets sleep onset with no significant adverse effect or dependency. Agomelatin, naphtahalenic compound, act as a potent MT1/MT2 melatonergic receptor agonist and serotonergic receptor antagonist was approved for treatment of depression in 2009. This dual action drug is the first melatonergic agent used in depression. Another melatonergic agonist, tasimelteon has high affinity for the MT1/MT2 receptors in humans. It was approved for the treatment of non-24 hours sleep-wake rhythm disorder. The newly developed melatonin and melatonergic drugs have the potential to be used extensively in various clinical situations and substitute the old benzodiazepine and its derivatives in the treatment of insomnia. However, the efficacy and safety of newly developed melatonergic drugs should be elucidated through long-term clinical trials.

Influence of clozapine on neurodevelopmental protein expression and behavioral patterns in animal model of psychiatric disorder induced by low-level of lead.

Exposure to lead during pregnancy is a risk factor for the development of psychiatric disorders in the offspring. In this study, we investigated whether exposure to low levels of lead acetate (0.2%) in drinking water during pregnancy and lactation causes behavioral impairment and affects the expression of proteins associated with neurodevelopment. Lead exposure altered several parameters in rat offspring compared with those unexposed in open-field, social interaction, and pre-pulse inhibition tests. These parameters were restored to normal levels after clozapine treatment. Western blot and immunohistochemical analyses of the hippocampus revealed that several neurodevelopmental proteins were downregulated in lead-exposed rats. The expression was normalized after clozapine treatment (5 mg/kg/day, postnatal day 35-56). These findings demonstrate that downregulation of several proteins in lead-exposed rats affected subsequent behavioral changes. Our results suggest that lead exposure in early life may induce psychiatric disorders and treatment with antipsychotics such as clozapine may reduce their incidence.

Effects of Panax ginseng C.A. Meyer extract on the offspring of adult mice with maternal immune activation.

To understand maternal immune activation (MIA) during prenatal development, the synthetic double­stranded RNA polyriboinosinic­polyribocytidylic acid [poly(I:C)] has been widely used in animal models to induce behavioral deficits similar to those in schizophrenia and other psychotic disorders. Panax ginseng C.A. Meyer (PG) extract is widely used to treat various kinds of nervous system disorders in Asia particularly China and Korea. The present study aimed to examine the effects of PG extract on MIA offspring using behavioral activity tests and protein expression analyses. Pregnant mice were exposed to poly(I:C) (5 mg/kg) or vehicle treatment on gestation day 9, and the resulting MIA offspring were subjected to vehicle or PG (300 mg/kg) treatment. In the acoustic startle response test, MIA­induced sensorimotor gating deficit was ameliorated by PG. The majority of behavioral parameters measured in the social interaction (non­aggressive or/and aggressive pattern), open field (number/duration of behavior) and forced swimming test (immobility behavior) were significantly altered in the MIA offspring. Western blot and immunohistochemical analyses of the medial prefrontal cortex indicated that the expression levels of certain neurodevelopmental proteins, including dihydropyrimidinase­related 2, LIM and SH3 domain 1, neurofilament medium, and discs large homolog 4, were decreased in the untreated MIA offspring, whereas PG treatment improved behavioral impairments and increased neurodevelopmental protein expression in MIA offspring. These results suggested that PG may be useful in neurodevelopmental disorder therapy, including psychiatric disorders such as schizophrenia, owing to its antipsychotic effects.

A Novel Secretory Vesicle from Deer Antlerogenic Mesenchymal Stem Cell-Conditioned Media (DaMSC-CM) Promotes Tissue Regeneration.

Multipotent stem cells have the capacity to generate terminally differentiated cell types of each lineage; thus, they have great therapeutic potential for a wide variety of diseases. The most widely available stem cells are derived from human tissues, and their use for therapeutic application is limited by their high cost and low productivity. Herein, we report that conditioned media of mesenchymal stem cells (MSCs) isolated from deer antlers enhanced tissue regeneration through paracrine action via a combination of secreted growth factors and cytokines. Notably, DaMSC-conditioned media (DaMSC-CM) enhanced hair regeneration by activating the Wnt signaling pathway. In addition, DaMSC-CM had regenerative potential in damaged skin tissue through induction of skin regeneration-related genes. Remarkably, we identified round vesicles derived from DaMSC-CM, with an average diameter of ~120 nm that were associated with hair follicle formation, suggesting that secretory vesicles may act as paracrine mediators for modulation of local cellular responses. In addition, these secretory vesicles could regulate the expression of Wnt-3a, Wnt-10b, and lymphoid enhancer-binding factor-1 (LEF-1), which are related to tissue renewal. Thus, our findings demonstrate that the use of DaMSC-CM as a unique natural model for rapid and complete tissue regeneration has possible application for therapeutic development.

Effects of Tianeptine on Adult Rats Following Prenatal Stress.

OBJECTIVE: Exposing a pregnant female to stress during the critical period of embryonic fetal brain development increases the risk of psychiatric disorders in the offspring. The objective of this study was to investigate the effect of antidepressant tianeptine on prenatally stressed (PNS) rats. METHODS: In this study, a repeated variable stress paradigm was applied to pregnant rats during the last week of gestation. To investigate the effects of antidepressant tianeptine on PNS rats, behavioral and protein expression analyses were performed. Forced swim test, open field test, and social interaction test were performed to determine changes in PNS rats compared to non-stressed offspring. Haloperidol was used as a positive control as an antipsychotic drug based on previous studies. RESULTS: Behavioral changes were restored after treatment with tianeptine or haloperidol. Western blot and immunohistochemical analyses of the prefrontal cortex revealed downregulation of several neurodevelopmental proteins in PNS rats. After treatment with tianeptine or haloperidol, their expression levels were increased. CONCLUSION: Downregulation of several proteins in PNS rats might have caused subsequent behavioral changes in PNS rats. After tianeptine or haloperidol treatment, behavioral changes in PNS rats were restored. Therefore, tianeptine might decrease incidence of prenatal stress related-psychiatric disorders such as depression and schizophrenia.

BBOX1 is down-regulated in maternal immune-activated mice and implicated in genetic susceptibility to human schizophrenia.

Prenatal exposure to infectious or inflammatory insults can increase the risk of developing neuropsychiatric disorders such as bipolar disorder, autism, and schizophrenia in later life. Gamma-butyrobetaine hydroxylase (BBOX 1) is an enzyme responsible for the biosynthesis of l-carnitine, a key molecule in fatty acid metabolism. This cytosolic dimeric protein belongs to the dioxygenase family. In this study, we investigated whether BBOX 1 expression was related to psychiatric disorder in an animal model. We also conducted a case-control study using 284 schizophrenia patients and 409 controls with single-nucleotide polymorphisms (SNPs) in the 5'-near region of BBOX 1. BBOX 1 expression was increased in the medial frontal cortex of a mouse model of schizophrenia induced by maternal immune activation. Furthermore, the genotype and allele frequencies of two SNPs (rs7939644 and rs10767592) were significantly associated with schizophrenia susceptibility. Our results suggest that BBOX 1 might be associated with maternal immune activation and schizophrenia susceptibility. Therefore, it might be involved in the pathophysiology of schizophrenia.

Antinociceptive effect of Valeriana fauriei regulates BDNF signaling in an animal model of fibromyalgia.

The genus Valeriana has been widely used in popular medicine for centuries, to treat sleep disorders, anxiety, epilepsy and insomnia. Recent studies have focused on the novel pharmacological effects of Valeriana fauriei Briq. (VF) species. Previous studies have attempted to determine the pharmacological functions of Valeriana in various human diseases, particularly with regards to its neuroprotective effects, and its ability to reduce pain and stress. The present study constructed an animal model of fibromyalgia (FM), which was induced by intermittent cold stress with slight modification. Subsequently, the study aimed to determine whether VF exerts antinociceptive effects on the FM­like model following oral administration of VF extracts. The effects of VF extracts on the FM model were investigated by analyzing behavioral activity, including pain, and detecting protein expression. In the behavioral analysis, the results of a nociception assay indicated that the pain threshold was significantly decreased in the FM group. Subsequently, western blotting and immunohistochemical analyses of the hippocampus demonstrated that the protein expression levels of brain­derived neurotrophic factor (BDNF) and phosphorylated­cAMP response element­binding protein were downregulated in the FM group. Conversely, VF restored these levels. These results suggested that the effects of VF extract on a model of FM may be associated with its modulatory effects on the BDNF signaling pathway in the hippocampus and medial prefrontal cortex. In conclusion, the mechanism underlying the protective effects of VF as a therapeutic agent against FM may involve the BDNF signaling pathway.

Association between endothelin­1 and fibromyalgia syndrome.

Fibromyalgia syndrome (FMS) is characterized by widespread chronic musculoskeletal pain, stiffness and pressure hyperalgesia at soft tissue tender points. Patients with FMS may exhibit a tendency towards cold extremities and cold­induced vasospasm. Endothelin­1 (EDN1) is a potent vasoconstrictor that is mainly produced by endothelial cells. The present study aimed to determine whether plasma expression levels avvnd single­nucleotide polymorphism (SNP; rs1800541) of the EDN1 gene were associated with FMS and/or any of its clinical variables. Plasma EDN1 levels were assessed by ELISA, and SNP genotypes were determined using polymerase chain reaction­high­resolution melting curve analysis. Patients with the TG genotype and the G allele may have an elevated risk of FMS. In addition, patients with FMS with the TG genotype and/or T allele exhibited higher plasma EDN1 levels compared with healthy controls. EDN1 levels increased significantly in patients with FMS compared with normal controls. In addition, EDN1 SNP was found to be associated with susceptibility to FMS.

Effects of tianeptine on symptoms of fibromyalgia via BDNF signaling in a fibromyalgia animal model.

Previous reports have suggested that physical and psychological stresses may trigger fibromyalgia (FM). Stress is an important risk factor in the development of depression and memory impairments. Antidepressants have been used to prevent stress-induced abnormal pain sensation. Among various antidepressants, tianeptine has been reported to be able to prevent neurodegeneration due to chronic stress and reverse decreases in hippocampal volume. To assess the possible effect of tianeptine on FM symptoms, we constructed a FM animal model induced by restraint stress with intermittent cold stress. All mice underwent nociceptive assays using electronic von Frey anesthesiometer and Hargreaves equipment. To assess the relationship between tianeptine and expression levels of brain-derived neurotrophic factor (BDNF), cAMP response element-binding protein (CREB), and phosphorylated cAMP response element-binding protein (p-CREB), western blotting and immunohistochemistry analyses were performed. In behavioral analysis, nociception tests showed that pain threshold was significantly decreased in the FM group compared to that in the control group. Western blot and immunohistochemical analyses of medial prefrontal cortex (mPFC) and hippocampus showed downregulation of BDNF and p-CREB proteins in the FM group compared to the control group. However, tianeptine recovered these changes in behavioral tests and protein level. Therefore, this FM animal model might be useful for investigating mechanisms linking BDNF-CREB pathway and pain. Our results suggest that tianeptine might potentially have therapeutic efficacy for FM.

PER2 is downregulated by the LPS-induced inflammatory response in synoviocytes in rheumatoid arthritis and is implicated in disease susceptibility.

The clinical symptoms of rheumatoid arthritis (RA) present with circadian variation, with joint stiffness and pain more prominent in the early morning. The mammalian clock genes, which include circadian locomotor output cycles kaput, brain and muscle Arnt-like protein 1, period and cryptochrome, regulate circadian rhythms. In order to identify the association between genetic polymorphisms in the circadian clock gene period 2 (PER2) and RA, the present study genotyped three PER2 single nucleotide polymorphisms (SNPs), rs934945, rs6754875, and rs2304674, using genetic information from 256 RA patients and 499 control subjects. Primary cultured rheumatoid synovial cells were stimulated with 10 µM lipopolysaccharide (LPS). Total protein was then extracted from the synovial cells following 12 and 24 h, and PER2 protein expression was assayed by immunoblotting. The rs2304674 SNP demonstrated a significant association with susceptibility to RA following Bonferroni correction. However, statistical analysis indicated that the SNPs were not associated with any clinical features of patients with RA. Immunoblotting analysis demonstrated that PER2 protein expression was decreased by LPS­induced inflammation in RA synovial cells; however, this was not observed in normal synovial cells. The results suggest that the PER2 gene may be a risk factor for RA, and expression of the PER2 protein may be affected by inflammation. Therefore, PER2 may contribute to the pathogenesis of RA.

A Fluidically Tunable Metasurface Absorber for Flexible Large-Scale Wireless Ethanol Sensor Applications.

In this paper, a novel flexible tunable metasurface absorber is proposed for large-scale remote ethanol sensor applications. The proposed metasurface absorber consists of periodic split-ring-cross resonators (SRCRs) and microfluidic channels. The SRCR patterns are inkjet-printed on paper using silver nanoparticle inks. The microfluidic channels are laser-etched on polydimethylsiloxane (PDMS) material. The proposed absorber can detect changes in the effective permittivity for different liquids. Therefore, the absorber can be used for a remote chemical sensor by detecting changes in the resonant frequencies. The performance of the proposed absorber is demonstrated with full-wave simulation and measurement results. The experimental results show the resonant frequency increases from 8.9 GHz to 10.04 GHz when the concentration of ethanol is changed from 0% to 100%. In addition, the proposed absorber shows linear frequency shift from 20% to 80% of the different concentrations of ethanol.

Effect of MDR1 gene polymorphisms on mortality in paraquat intoxicated patients.

Paraquat is a fatal herbicide following acute exposure. Previous studies have suggested that multidrug resistance protein 1 (MDR1) might help remove paraquat from the lungs and the kidney. MDR1 single-nucleotide polymorphisms (SNPs) are involved in the pharmacokinetics of many drugs. The purpose of this study was to determine whether MDR1 SNPs were associated with the mortality in paraquat intoxicated patients. We recruited 109 patients admitted with acute paraquat poisoning. They were genotyped for C1236T, G2677T/A, and C3435T single-nucleotide polymorphisms (SNPs) of MDR1 gene. Their effects on mortality of paraquat intoxicated patients were evaluated. Overall mortality rate was 66.1%. Regarding the C1236T of the MDR1 gene polymorphism, 21 (19.3%) had the wild type MDR1 while 88 (80.7%) had homozygous mutation. Regarding the C3435T MDR1 gene polymorphism, 37(33.9%) patients had the wild type, 23 (21.1%) had heterozygous mutation, and 49 (45.0%) had homozygous mutation. Regarding the G2677T/A MDR1 gene polymorphism, 38 (34.9%) patients had the wild type, 57 (52.3%) had heterozygous mutation, and 14 (12.8%) had homozygous mutation. None of the individual mutations or combination of mutations (two or three) of MDR1 SNP genotypes altered the morality rate. The mortality rate was not significantly different among SNP groups of patients with <4.0 µg/mL paraquat. In conclusion, MDR1 SNPs have no effect on the mortality rate of paraquat intoxicated patients.

Wideband-Switchable Metamaterial Absorber Using Injected Liquid Metal.

Metamaterial absorbers can provide good solutions for radar-cross-section (RCS) reduction. In spite of their attractive features of thinness, lightness, and low cost, resonant metamaterial absorbers have a drawback of narrow bandwidth. For practical radar applications, wideband absorbers are necessary. In this paper, we propose a wideband-switchable metamaterial absorber using liquid metal. In order to reduce RCS both for X-band and C-band, the switchable Jerusalem cross (JC) resonator is introduced. The JC resonator consists of slotted circular rings, chip resistors, and microfluidic channels. The JC resonator is etched on a flexible printed circuit board (FPCB), and the microfluidic channels are laser-etched on a polydimethylsiloxane (PDMS) material. The proposed absorber can switch the absorption frequency band by injecting a liquid metal alloy into the channels. The performance of the absorber was demonstrated through full-wave simulation and through measurements employing prototypes. The experimental results showed absorption ratios of over 90% from 7.43 GHz to 14.34 GHz, and from 5.62 GHz to 7.3 GHz, with empty channels and liquid metal-filled channels, respectively. Therefore, the absorption band was successfully switched between the C-band (4-8 GHz) and the X-band (8-12 GHz) by injecting liquid metal eutectic gallium indium alloy (EGaIn) into the channels.

Frequency-tunable metamaterial absorber using a varactor-loaded fishnet-like resonator.

A frequency-tunable metamaterial absorber is designed with the unit cell consisting of a varactor-loaded fishnet-like resonator. This geometry allows all cathode and anode pads of the unit cells to be connected to their counterparts. Hence, only the ends of the periodic structure need to be biased, reducing the complexity of the bias network. The absorber was modeled using a full-wave simulation tool and verified experimentally with a 20×20 unit-cell prototype. Using free-space measurements, the absorber shows >90% absorption ratio from 3.96 to 5.29 GHz with a frequency tuning ratio of 28.7%, when the reverse voltage varied from 0 to 19 V.

Effect of Valeriana fauriei extract on the offspring of adult rats exposed to prenatal stress.

Exposing a pregnant female to stress is a risk factor for the development of psychiatric disorders in the offspring. In the present study, we examined the effects of an extract of Valeriana fauriei (VF) root (100 mg/kg/day, administered on postnatal days 35-56) on behavioral patterns as well as protein expression in the prefrontal cortex of the offspring of prenatally-stressed rats. Modified behavioral tests, including the forced swim test, the open field test, a social interaction test and the prepulse inhibition test were performed and many of the parameters were found to decrease in the offspring of the rats exposed to PNS compared with the offspring of the non-stressed rats. Western blot and immunohistochemical analyses of the prefrontal cortex revealed that the downregulation of several neurodevelopmental proteins in the offspring of rats dams exposed to PNS was reversed after treatment with VF extract. These findings demonstrate that the downregulation of several proteins in the prefrontal cortex of the offspring of prenatally­stressed rats may be associated with subsequent behavioral changes, and that these phenomena recovered following VF treatment. Our results suggest that VF decreases the incidence of prenatal stress related-psychiatric disorders, such as depression and schizophrenia.

Abnormal Nocturnal Behavior due to Hypoglycemia in a Patient with Type 2 Diabetes.

Abnormal nocturnal behavior can have many causes, including primary sleep disorder, nocturnal seizures, and underlying medical or neurological disorders. A 79-year-old woman with type 2 diabetes was admitted for evaluation of abnormal nocturnal behavior. Every night at around 04:30 she was observed displaying abnormal behavior including leg shaking, fumbling with bedclothes, crawling around the room with her eyes closed, and non-responsiveness to verbal communication. Polysomnography with 20-channel electroencephalography (EEG) was performed. EEG showed that the posterior dominant rhythm was slower than that observed in the initial EEG, with diffuse theta and delta activities intermixed, and no epileptiform activity. The serum glucose level was 35 mg/dL at that time, and both the EEG findings and clinical symptoms were resolved after an intravenous injection of 50 mL of 50% glucose. These results indicate that nocturnal hypoglycemia should be considered as one of the possible etiologies in patients presenting with abnormal nocturnal behavior.

Toxicokinetics of paraquat in Korean patients with acute poisoning.

To conduct a kinetic study of paraquat (PQ), we investigated 9 patients with acute PQ intoxication. All of them ingested more than 20 ml of undiluted PQ herbicide to commit suicide and arrived at our hospital early, not later than 7 h after PQ ingestion. The urine dithionite test for PQ in all of the nine patients was strongly positive at emergency room. Blood samples were obtained every 30 min for the first 2~3 h and then every 1 or 2 h, as long as the clinical progression was stable among the patients for 30 h after PQ ingestion. The area under the plasma concentration-time curve (AUCinf), which was extrapolated to infinity, was calculated using the trapezoidal rule. Toxicokinetic parameters, such as the terminal elimination half-life, apparent oral clearance, and apparent volume of distribution (Vd/F) were calculated. The maximum PQ concentration (Cmax) and the time to reach maximum PQ concentration (Tmax) were also obtained. Plasma PQ concentrations in nine patients were well described by a bi-exponential curve with a mean terminal elimination half-life of 13.1±6.8 h. Cmax and AUCinf were 20.8±25.7 mg/l and 172.5±160.3 h·mg/l, respectively. Apparent volume of distribution and apparent oral clearance were 50.9±61.3 l/kg and 173.4±111.2 l/h, respectively. There were a significant correlation (r =0.84; p<0.05) between the PQ amount ingested and Cmax. AUCinf also showed a significant correlation (r =0.83; p<0.05) with the PQ amount ingested. These correlations provide evidence that PQ has dose-linear toxicokinetic characteristics.

Frequency-Switchable Metamaterial Absorber Injecting Eutectic Gallium-Indium (EGaIn) Liquid Metal Alloy.

In this study, we demonstrated a new class of frequency-switchable metamaterial absorber in the X-band. Eutectic gallium-indium (EGaIn), a liquid metal alloy, was injected in a microfluidic channel engraved on polymethyl methacrylate (PMMA) to achieve frequency switching. Numerical simulation and experimental results are presented for two cases: when the microfluidic channels are empty, and when they are filled with liquid metal. To evaluate the performance of the fabricated absorber prototype, it is tested with a rectangular waveguide. The resonant frequency was successfully switched from 10.96 GHz to 10.61 GHz after injecting liquid metal while maintaining absorptivity higher than 98%.

Changes in Dpysl2 expression are associated with prenatally stressed rat offspring and susceptibility to schizophrenia in humans.

Exposure to stress during critical periods of fetal brain development is an environmental risk factor for the development of schizophrenia in adult offspring. In the present study, a repeated-variable stress paradigm was applied to pregnant rats during the last week of gestation, which is analogous to the second trimester of brain development in humans. Behavioral and proteomic analyses were conducted in prenatally-stressed (PNS) adult offspring and non-stressed (NS) adult controls. In the behavioral tests, grooming behavior in the social interaction test, line-crossing behavior in the open field test, and swimming behavior in the forced swimming test were decreased in the PNS group. Western blot analysis and immunohistochemical analysis revealed that the expression of dihydropyrimidinase-like 2 (Dpysl2) or collapsin response mediator protein 2 (Crmp2) was downregulated in the prefrontal cortex and hippocampus of rats in the PNS group. Subsequently, single-nucleotide polymorphisms (SNPs) of the human dihydropyrimidinase-like 2 (DPYSL2) gene were analyzed in a population. Two functional SNPs (rs9886448 in the promoter region and rs2289593 in the exon region) were associated with susceptibility to schizophrenia. The present findings demonstrated that the downregulation of genes such as Dpysl2 and Dypsl3 in a rat model of prenatal stress may affect subsequent behavioral changes and that polymorphisms of the DPYSL2 gene in humans may be associated with the development of schizophrenia. Taken together with previous studies investigating the association between the DPYSL2 gene and schizophrenia, the present findings may contribute additional evidence regarding developmental theories of the pathophysiology of schizophrenia.

Flexible inkjet-printed metamaterial absorber for coating a cylindrical object.

In this paper, a novel flexible inkjet-printed metamaterial absorber is proposed. The unit cell of the metamaterial is designed with a modified Jerusalem-cross ring resonator and is inkjet printed with silver nanoparticle ink on a flexible polymer film. All fabrication processes are performed using a commercial printer (EPSON WF-7011). The absorber's flexibility and absorption performance are demonstrated by measuring the absorption ratio after coating the proposed absorber on a cylindrical object with a radius of 4.56 cm. An absorption rate exceeding 99% is achieved at 9.21 GHz for both flat and cylindrical surfaces. In addition, the cylindrical model attains an absorption rate higher than 96% for all polarization angles, and a high absorption rate of 95% is preserved until the incident angle is less than 30þ.