The Development of a Regulator of Human Serine Racemase for N-Methyl-D-aspartate Function.

It is crucial to regulate N-methyl-D-aspartate (NMDA) function bivalently depending on the central nervous system (CNS) conditions. CNS disorders with NMDA hyperfunction are involved in the pathogenesis of neurotoxic and/or neurodegenerative disorders with elevated D-serine, one of the NMDA receptor co-agonists. On the contrary, NMDA-enhancing agents have been demonstrated to improve psychotic symptoms and cognition in CNS disorders with NMDA hypofunction. Serine racemase (SR), the enzyme regulating both D- and L-serine levels through both racemization (catalysis from L-serine to D-serine) and ß-elimination (degradation of both D- and L-serine), emerges as a promising target for bidirectional regulation of NMDA function. In this study, we explored using dimethyl malonate (DMM), a pro-drug of the SR inhibitor malonate, to modulate NMDA activity in C57BL/6J male mice via intravenous administration. Unexpectedly, 400 mg/kg DMM significantly elevated, rather than decreased (as a racemization inhibitor), D-serine levels in the cerebral cortex and plasma. This outcome prompted us to investigate the regulatory effects of dodecagalloyl-α-D-xylose (α12G), a synthesized tannic acid analog, on SR activity. Our findings showed that α12G enhanced the racemization activity of human SR by about 8-fold. The simulated and fluorescent assay of binding affinity suggested a noncooperative binding close to the catalytic residues, Lys56 and Ser84. Moreover, α12G treatment can improve behaviors associated with major CNS disorders with NMDA hypofunction including hyperactivity, prepulse inhibition deficit, and memory impairment in animal models of positive symptoms and cognitive impairment of psychosis. In sum, our findings suggested α12G is a potential therapeutic for treating CNS disorders with NMDA hypofunction.

Protective Evaluation of Compounds Extracted from Root of Rhodiola rosea L. against Methylglyoxal-Induced Toxicity in a Neuronal Cell Line.

Rhodiola rosea L. (R. rosea) is one of the most beneficial medicinal plants and it is studied as an adaptogen. This study aims to evaluate the neuroprotective activity of compounds extracted from the root of R. rosea against methylglyoxal (MG)-induced apoptosis in neuro-2A (N2A) cells. The root of R. rosea was extracted with ethanol and partitioned with water, ethyl acetate, and n-butanol fractions to evaluate acetylcholinesterase (AChE) inhibitory activity and neuroprotective activity. The ethyl acetate fraction exhibited the highest values of AChE inhibitory activity (49.2% ± 3%) and cell viability (50.7% ± 4.8%) for neuroprotection. The structure identification of the most potential fraction (ethyl acetate fraction) revealed 15 compounds, consisting of three tannins, five flavonoids, and seven phenolics by infrared spectroscopy, nuclear magnetic resonance, and mass spectroscopy. All compounds were evaluated for their neuroprotective activity. Salidroside had the most potential neuroprotective activity. Gallic acid and methyl gallate had potential cytotoxicity in N2A cells. This study showed that R. rosea might have potential neuroprotective activities.

Gallate-induced nanoparticle uptake by tumor cells: Structure-activity relationships.

How nanoparticles interact with biological systems determines whether they can be used in theranostic applications. It has been demonstrated that tea catechins, may enhance interactions of magnetic nanoparticles (MNPs) with tumor cells and the subsequent cellular internalization of MNPs. As part of the chemical structure of the major tea catechins, gallates are found in a variety of plants and thus food components. We asked whether the structure of gallate might act as a pharmacophore in the enhancement of the effects of MNP-cell interactions. Uptake of dextran-coated MNPs by glioma cells and cell-associated MNPs (MNPcell) were respectively analyzed by confocal microscopy and a colorimetric iron assay. Co-incubation of MNPs and gallates, such as gallic acid and methyl gallate, induced a concentration-dependent increase in MNPcell, which was associated with co-localization of internalized MNPs and lysosomes. An analysis of the structure-activity relationship (SAR) revealed that the galloyl moiety exerted the most prominent enhancement effects on MNPcell which was further potentiated by the application of magnetic force; catechol coupled with a conjugated carboxylic acid side chain displayed comparable effects to gallate. Blockade or reduction in the number of hydroxyl groups rendered these compounds less effective, but without inducing cytotoxicity. The SAR results suggest that neighboring hydroxyl groups on the aromatic ring form an essential scaffold for the uptake effects; a similar SAR on antioxidant activities was also observed using a free radical-scavenging method. The results provide pivotal information for theranostic applications of gallates by facilitating nanoparticle-cell interactions and nanoparticle internalization by tumor cells.

Melanogenesis Inhibitors from the Rhizoma of Ligusticum Sinense in B16-F10 Melanoma Cells In Vitro and Zebrafish In Vivo.

The rhizoma of Ligusticum sinense, a Chinese medicinal plant, has long been used as a cosmetic for the whitening and hydrating of the skin in ancient China. In order to investigate the antimelanogenic components of the rhizoma of L. sinense, we performed an antimelanogenesis assay-guided purification using semi-preparative HPLC accompanied with spectroscopic analysis to determine the active components. Based on the bioassay-guided method, 24 compounds were isolated and identified from the ethyl acetate layer of methanolic extracts of L. sinense, and among these, 5-[3-(4-hydroxy-3-methoxyphenyl)allyl]ferulic acid (1) and cis-4-pentylcyclohex-3-ene-1,2-diol (2) were new compounds. All the pure isolates were subjected to antimelanogenesis assay using murine melanoma B16-F10 cells. Compound 1 and (3S,3aR)-neocnidilide (8) exhibited antimelanogenesis activities with IC50 values of 78.9 and 31.1 µM, respectively, without obvious cytotoxicity. Further investigation showed that compound 8 demonstrated significant anti-pigmentation activity on zebrafish embryos (10‒20 µM) compared to arbutin (20 µM), and without any cytotoxicity against normal human epidermal keratinocytes. These findings suggest that (3S,3aR)-neocnidilide (8) is a potent antimelanogenic and non-cytotoxic natural compound and may be developed potentially as a skin-whitening agent for cosmetic uses.

TO-56-can packaged colorless WRC-FPLD for QAM OFDM transmission at 42 Gbit/s over 25-km SMF.

The weak-resonant-cavity Fabry-Perot laser diode (WRC-FPLD) with colorless and channelized mode features is a new-class optical transmitter fulfilling the need of next-generation communications. By packaging the colorless WRC-FPLD transmitter with a 10-GHz transistor-outline-56-can (TO-56-can), the premier demonstration on directly modulated 42-Gbit/s/channel quadrature amplitude modulation (QAM) orthogonal frequency division multiplexing (OFDM) transmission is demonstrated via wavelength injection-locking. Enlarging the injection level effectively up-shifts the relaxation oscillation peak and suppresses the relative intensity noise, which facilitates the TO-56-can packaged WRC-FPLD to improve its modulation throughput bandwidth to 9 GHz and enhance its signal-to-noise ratio to 22 dB. By pre-amplifying the directly modulated QAM-OFDM data with a total raw bit rate of 42 Gbit/s, the receiving bit-error-rate (BER) under back-to-back transmission can be reduced below the forward-error-correction (FEC) limited BER of 3.8 × 10(-3). Such a colorless WRC-FPLD enables the QAM-OFDM transmission over a 25-km long single-mode-fiber based metropolitan access network with its BER matching the FEC criterion at a receiving power of -2 dBm.

Suppressing the relaxation oscillation noise of injection-locked WRC-FPLD for directly modulated OFDM transmission.

By up-shifting the relaxation oscillation peak and suppressing its relative intensity noise in a weak-resonant-cavity Fabry-Perot laser diode (WRC-FPLD) under intense injection-locking, the directly modulated transmission of optical 16 quadrature amplitude modulation (QAM) orthogonal frequency division multiplexing (OFDM) data-stream is demonstrated. The total bit rate of up to 20 Gbit/s within 5-GHz bandwidth is achieved by using the OFDM subcarrier pre-leveling technique. With increasing the injection-locking power from -12 to -3 dBm, the effective reduction on threshold current of the WRC-FPLD significantly shifts its relaxation oscillation frequency from 5 to 7.5 GHz. This concurrently induces an up-shift of the peak relative intensity noise (RIN) of the WRC-FPLD, and effectively suppresses the background RIN level to -104 dBc/Hz within the OFDM band between 3 and 6 GHz. The enhanced signal-to-noise ratio from 16 to 20 dB leads to a significant reduction of bit-error-rate (BER) of the back-to-back transmitted 16-QAM-OFDM data from 1.3 × 10(-3) to 5 × 10(-5), which slightly degrades to 1.1 × 10(-4) after 25-km single-mode fiber (SMF) transmission. However, the enlarged injection-locking power from -12 to -3 dBm inevitably declines the modulation throughput and increases its negative throughput slope from -0.8 to -1.9 dBm/GHz. After pre-leveling the peak amplitude of the OFDM subcarriers to compensate the throughput degradation of the directly modulated WRC-FPLD, the BER under 25-km SMF transmission can be further improved to 3 × 10(-5) under a receiving power of -3 dBm.

Coherently wavelength injection-locking a 600-µm long cavity colorless laser diode for 16-QAM OFDM at 12 Gbit/s over 25-km SMF.

The coherent injection-locking and directly modulation of a long-cavity colorless laser diode with 1% end-facet reflectance and weak-resonant longitudinal modes is employed as an universal optical transmitter to demonstrated for optical 16-QAM OFDM transmission at 12 Gbit/s over 25 km in a DWDM-PON system. The optimized bias current of 30 mA (~1.5Ith) with corresponding extinction ratio (ER) of 6 dB and the external injection power of -9 dBm is (are) required for such a wavelength-locked universal transmitter to carry the 16-QAM and 122-subcarrier formatted OFDM and data-stream. By increasing external injection-locking from -9 dBm to 0 dBm, the peak-to-peak chirp of the OFDM data stream reduces from 7.7 to 5.4 GHz. The side mode suppression ratio (SMSR) of up to 50 dB is achieved with wider detuning range between -0.5 nm to 2.0 nm under an injection power of 0 dBm. By modulating such a colorless laser diode with an OFDM data stream of 122 subcarriers at a central carrier frequency of 1.5625 GHz and a total bandwidth of 3 GHz, the transmission data rate of up to 12 Gbit/s in standard single-mode fiber over 25 km is demonstrated to achieve an error vector magnitude (EVM) of 5.435%. Such a universal colorless DWDM-PON transmitter can deliver the optical OFDM data-stream at 12 Gbit/s QAM-OFDM data after 25-km transmission with a receiving power sensitivity of -7 dBm at BER of 3.6 × 10(-7) when pre-amplifying the OFDM data by 5 dB.

Determination of nimetazepam and 7-aminonimetazepam in human urine by using liquid chromatography-tandem mass spectrometry.

We report determination of metabolites of popular drugs of abuse, including nimetazepam and nitrazepam, in urine by using liquid chromatography/mass spectrometry. Nimetazepam and its metabolites, 7-aminonimetazepam and nitrazepam, were extracted by solid-phase extraction using a DAU cartridge. An ammonium acetate buffer solution (pH 4) and a Luna polar-RP column were selected as the mobile and stationary phase, respectively, for liquid chromatography. Mass spectrometry was used for analysis and was optimized for operation in the positive mode for all analytes. The urine specimens were screened for the presence of nimetazepam and its metabolites nitrazepam and 7-aminonimetazepam at a concentration of 0.1ng/mL. Presence of 7-aminonimetazepam in the urine was an indicator of the subject being a probable abuser of nimetazepam.

The characteristics and distribution of dental anomalies in patients with cleft.

BACKGROUND: Dental anomalies associated with different severities of cleft lip and palate have been rarely reported. This retrospective study investigates the characteristics of dental anomalies associated with different types of cleft, and compares the dental anomaly traits based on sex and severity of cleft. METHODS: Cleft patients born in 1995 with qualified diagnostic records from 7 to 11 years were included for evaluation. Records were retrieved from database of Chang Gung Craniofacial Center, including panoramic radiographs and intraoral photographs. In total, 196 patients with complete records were included in the evaluation. This study compares the dental anomalies associated with each type of cleft. RESULTS: The frequency of dental anomalies in the maxillary incisor area in the cleft palate (CP) group (20%) was significantly lower than that in other groups. The frequency of missing maxillary lateral incisors (MLIs) increased as the cleft severity increased. Supernumerary teeth and missing lower incisors exhibited the opposite trend. No sexual dimorphism appeared in terms of the frequencies of peg laterals and missing MLIs. The distribution patterns of missing MLIs and peg laterals in males, but not in females, were consistent for the three types of unilateral clefts. CONCLUSION: Regarding the characteristics of dental anomalies among the three unilateral clefts, missing MLIs, supernumerary teeth, and missing lower incisors were found to be related to cleft severity. The maxillary lateral incisor was the most affected tooth in the cleft area. The frequency of missing MLIs and peg laterals was not sexual dimorphic, but the distribution pattern was different between the sexes.

Vitamin K3-2,3-epoxide induction of apoptosis with activation of ROS-dependent ERK and JNK protein phosphorylation in human glioma cells.

2-Methyl-1,4-naphthoquinone (menadione or vitamin K3; EPO) and K3-2,3-epoxide (EPO1), but not vitamin K3-3-OH (EPO2), exhibited cytotoxicity that caused DNA fragmentation and chromatin condensation in U87 and C6 cells. EPO1 showed more-potent cytotoxicity than EPO, and the IC(50) values of EPO and EPO1 in U87 cells were 37.5 and 15.7µM, respectively. Activation of caspase 3 enzyme activity with cleavage of caspase 3 protein was detected in EPO1-treated U87 and C6 cells, and the addition of the caspase 3 peptidyl inhibitor, DEVD-FMK, reduced the cytotoxic effect of EPO1. An increase in the intracellular ROS level by EPO1 was observed in the DCHF-DA analysis, and EPO1-induced apoptosis and caspase 3 protein cleavage were prevented by adding the antioxidant, N-acetyl-cysteine (NAC), with decreased ROS production elicited by EPO1. Activation of ERK and JNK, but not p38, via phosphorylation induction was identified in EPO1- but not EPO- or EPO2-treated U87 and C6 cells, and this was blocked by adding NAC. However, the ERK inhibitor, PD98059, and the JNK inhibitor, SP600125, showed no effect on EPO1-induced cytotoxicity in either cell type. Our findings demonstrate that 2,3-epoxide substitution significantly potentiates the apoptotic effect of vitamin K3 via stimulating ROS production, which may be useful in the chemotherapy of glioblastoma cells.