DFT-Spectroscopy Integrated Identification Method on Unknown Terrorist Chemical Mixtures by Incorporating Experimental and Theoretical GC-MS, NMR, IR, and DFT-NMR/IR Data.

In the event of a chemical attack, the rapid identification of unknown chemical agents is critical for an effective emergency response and treatment of victims. However, identifying unknown compounds is difficult, particularly when relying on traditional methods such as gas and liquid chromatography-mass spectrometry (GC-MS, LC-MS). In this study, we developed a density functional theory and spectroscopy integrated identification method (D-SIIM) for the possible detection of unknown or unidentified terrorist materials, specifically chemical warfare agents (CWAs). The D-SIIM uses a combination of GC-MS, nuclear magnetic resonance (NMR) spectroscopy, infrared (IR) spectroscopy, and quantum chemical calculation-based NMR/IR predictions to identify potential CWA candidates based on their chemical signatures. Using D-SIIM, we successfully verified the presence of blister and nerve agent simulants in samples by excluding other compounds (ethyl propyl sulfide and methylphosphonic acid), which were predicted to be candidates with high probability by GC-MS. The findings of this study demonstrate that the D-SIIM can detect substances that are likely present in CWA mixtures and can be used to identify unknown terrorist chemicals.

Inhibition of neuronal peroxisome proliferator-activated receptor-γ attenuates motor function improvement after spinal cord injury in rats.

Traumatic spinal cord injury (SCI) causes secondary damage in injured and adjacent regions due to temporal deprivation of oxygen and energy supply. Peroxisome proliferator-activated receptor γ (PPARγ) is known to regulate cell survival mechanisms such as hypoxia, oxidative stress, inflammation and energy homeostasis in various tissues. Thus, PPARγ has the potential to show neuroprotective properties. However, the role of endogenous spinal PPARγ in SCI is not well established. In this study, under isoflurane inhalation, a 10-g rod was freely dropped onto the exposed spinal cord after T10 laminectomy using a New York University impactor in male Sprague-Dawley rats. Cellular localization of spinal PPARγ, locomotor function and mRNA levels of various genes including NFκB-targeted pro-inflammatory mediators after intrathecal administration of PPARγ antagonists, agonists or vehicles in SCI rats were then analysed. In both sham and SCI rats, spinal PPARγ was presented in neurons but not in microglia or astrocytes. Inhibition of PPARγ induced IκB activation and increased mRNA levels of pro-inflammatory mediators. It also suppressed recovery of locomotor function with myelin-related gene expression in SCI rats. However, a PPARγ agonist showed no beneficial effects on the locomotor performances of SCI rats, although it further increased the protein expression of PPARγ. In conclusion, endogenous PPARγ has a role in anti-inflammation after SCI. Inhibition of PPARγ might have a negative influence on motor function recovery through accelerated neuroinflammation. Nonetheless, exogenous PPARγ activation does not appear to effectively help with functional improvement after SCI.

Therapeutic Effect of BDNF-Overexpressing Human Neural Stem Cells (F3.BDNF) in a Contusion Model of Spinal Cord Injury in Rats.

The most common type of spinal cord injury is the contusion of the spinal cord, which causes progressive secondary tissue degeneration. In this study, we applied genetically modified human neural stem cells overexpressing BDNF (brain-derived neurotrophic factor) (F3.BDNF) to determine whether they can promote functional recovery in the spinal cord injury (SCI) model in rats. We transplanted F3.BDNF cells via intrathecal catheter delivery after a contusion of the thoracic spinal cord and found that they were migrated toward the injured spinal cord area by MR imaging. Transplanted F3.BDNF cells expressed neural lineage markers, such as NeuN, MBP, and GFAP and were functionally connected to the host neurons. The F3.BDNF-transplanted rats exhibited significantly improved locomotor functions compared with the sham group. This functional recovery was accompanied by an increased volume of spared myelination and decreased area of cystic cavity in the F3.BDNF group. We also observed that the F3.BDNF-transplanted rats showed reduced numbers of Iba1- and iNOS-positive inflammatory cells as well as GFAP-positive astrocytes. These results strongly suggest the transplantation of F3.BDNF cells can modulate inflammatory cells and glia activation and also improve the hyperalgesia following SCI.

Effect of the Combination of CI-988 and Morphine on Neuropathic Pain after Spinal Cord Injury in Rats.

Cholecystokinin is known to be involved in the modulation of nociception and to reduce the efficacy of morphine analgesia. This study investigated the effects of intrathecal administration of morphine and the cholecystokinin type B antagonist CI-988 on below-level neuropathic pain after spinal cord injury in rats. We also examined the interaction of morphine and CI-988 in the antinociceptive effect. Both morphine and CI-988 given individually increased the paw withdrawal threshold to mechanical stimulation in a dose-dependent manner. The combination of ineffective doses of intrathecally administered CI-988 and morphine produced significant analgesic effects and the combination of effective doses resulted in analgesic effects that were greater than the sum of the individual effects of each drug. Thus, morphine showed a synergistic interaction with CI-988 for analgesia of central neuropathic pain.

Spectroscopic identification of isomeric jet-cooled benzyl-type radicals generated from 4-fluoro-o-xylene.

Vibronically excited but jet-cooled benzyl-type radicals were generated by the corona discharge of precursor 4-fluoro-o-xylene seeded in a large amount of inert carrier gas helium using a pinhole-type glass nozzle, from which the vibronic emission spectra were observed with a long-path monochromator in the visible region. From an analysis of the spectra observed, we identified the existence of two isomeric benzyl-type radicals, 2-methyl-4-fluorobenzyl and 2-methyl-5-fluorobenzyl radicals in corona discharge, and determined the electronic energy of the D1 → D0 transition and several vibrational mode frequencies in the D0 state of both isomers for the first time.

Protection of the Vascular System by Polyethylene Glycol Reduces Secondary Injury Following Spinal Cord Injury in Rats.

BACKGROUND: Polyethylene glycol (PEG) is a hydrophilic polymer, which has been known to have a neuroprotective effect by sealing the ruptured cell membrane, but PEG effects on the vascular systems and its underlying mechanisms remain unclear. Here, we showed the neuroprotective effect of PEG by preventing damage to the vascular system. METHODS: A spinal contusion was made at the T11 segment in male Sprague-Dawley rats. PEG was injected into the subdural space immediately after SCI. Vascular permeability was assessed for 24 h after SCI using intraperitoneally injected Evans blue dye. Junctional complexes were stained with CD31 and ZO-1. Infarct size was analyzed using triphenyltetrazolium chloride, and blood vessels were counted in the epicenter. Behavioral tests for motor and sensory function were performed for 6 weeks. And then the tissue-sparing area was assessed. RESULTS: Immediately applied PEG significantly reduced the vascular permeability at 6, 12, and 24 h after SCI when it compared to saline, and infarct size was also reduced at 0, 6, and 24 h after SCI. In addition, a great number of blood vessels were observed in PEG group at 6 and 24 h after SCI compared to those of the saline group. The PEG group also showed a significant improvement in motor function. And tissue-sparing areas in the PEG were greater than those of the saline group. CONCLUSION: The present results provide preclinical evidence for the neuroprotective effects of PEG as a promising therapeutic agent for reducing secondary injury following SCI through vascular protection.

Spectroscopic observation of jet-cooled 2-fluoro-m-xylyl radical.

The jet-cooled 2-fluoro-m-xylyl radical was generated and vibronically excited in a corona excited supersonic expansion from precursor 2-fluoro-m-xylene seeded in a large amount of carrier gas helium. The well-resolved visible vibronic emission spectrum of the jet-cooled 2-fluoro-m-xylyl radical was recorded using a long-path monochromator. From the analysis of the spectrum, we determine an accurate electronic energy of the D(1) → D(0) transition and the frequencies of vibrational modes in the ground electronic state by comparison with those of ab initio calculations and the known spectroscopic data of 2-fluoro-m-xylene for the first time.

Spectroscopic identification of benzyl-type radicals generated by corona discharge of 2-chloro-4-fluorotoluene.

By means of a technique of corona excited supersonic expansion coupled with a pinhole-type glass nozzle, we generated vibronically excited but jet-cooled benzyl-type radicals from precursor 2-chloro-4-fluorotoluene seeded in a large amount of inert carrier gas He. From an analysis of the visible vibronic emission spectrum, we found evidence of the formation of the 2-chloro-4-fluorobenzyl and 4-fluorobenzyl radicals. A possible pathway for the formation of these benzyl-type radicals is herein proposed. Also, the electronic energy in the D(1) → D(0) transition and the vibrational mode frequencies of the 2-chloro-4-fluorobenzyl radical in the ground electronic state were accurately determined, for the first time, by comparison with ab initio calculations and the known vibrational data of the precursor.

Precisely predicting the 1H and 13C NMR chemical shifts in new types of nerve agents and building spectra database.

Following the recent terrorist attacks using Novichok agents and the subsequent decomposition operations, understanding the chemical structures of nerve agents has become important. To mitigate the ever-evolving threat of new variants, the Organization for the Prohibition of Chemical Weapons has updated the list of Schedule 1 substances defined by the Chemical Weapons Convention. However, owing to the several possible structures for each listed substance, obtaining an exhaustive dataset is almost impossible. Therefore, we propose a nuclear magnetic resonance-based prediction method for 1H and 13C NMR chemical shifts of Novichok agents based on conformational and density functional study calculations. Four organophosphorus compounds and five G- and V-type nerve agents were used to evaluate the accuracy of the proposed procedure. Moreover, 1H and 13C NMR prediction results for an additional 83 Novichok candidates were compiled as a database to aid future research and identification. Further, this is the first study to successfully predict the NMR chemical shifts of Novichok agents, with an exceptional agreement between predicted and experimental data. The conclusions enable the prediction of all possible structures of Novichok agents and can serve as a firm foundation for preparation against future terrorist attacks using new variants of nerve agents.

Confirmed assignments of isomeric dimethylbenzyl radicals generated by corona discharge.

The controversial vibronic assignments of isomeric dimethylbenzyl radicals were clearly resolved by using different precursors. By employing corresponding dimethylbenzyl chlorides as precursors, we identified the origins of the vibronic bands of the dimethylbenzyl radicals generated by corona discharge of 1,2,4-trimethylbenzene. From the analysis of the spectra observed from the dimethylbenzyl chlorides in a corona excited supersonic expansion, we revised previous assignments of the 3,4-, 2,4-, and 2,5-dimethylbenzyl radicals. Spectroscopic data of electronic transition and vibrational mode frequencies in the ground electronic state of each isomer were accurately determined by comparing them with those obtained by an ab initio calculation and with the known vibrational data of 1,2,4-trimethylbenzene.

18F-THK-5351, Fluorodeoxyglucose, and Florbetaben PET Images in Atypical Alzheimer's Disease: A Pictorial Insight into Disease Pathophysiology.

The recent advance of positron emission tomography (PET) tracers as biomarkers in Alzheimer's disease (AD) provides more insight into pathophysiology, preclinical diagnosis, and further therapeutic strategies. However, synergistic processes or interactions between amyloid and tau deposits are still poorly understood. To better understand their relationship in focal brain changes with clinical phenotypes, we focused on region-specific or atypical AD characterized by focal clinical presentations: Posterior cortical atrophy (PCA) and logopenic variant of primary progressive aphasia (lpvPPA). We compared three different PET images with 18F-THK-5351 (tau), 18F-Florbetaben (amyloid beta, Aß), and 18F-Fluorodeoxyglucose (glucose metabolism) to investigate potential interactions among pathologies and clinical findings. Whereas the amyloid accumulations were widespread throughout the neocortex, tau retentions and glucose hypometabolism showed focal changes corresponding to the clinical features. The distinctly localized patterns were more prominent in tau PET imaging. These findings suggest that tau pathology correlates more closely to the clinical symptoms and the neurodegenerative processes than Aß pathology in AD.

Clinical Implications of Amyloid-Beta Accumulation in Occipital Lobes in Alzheimer's Continuum.

A substantial amount of amyloid-beta (Aß) accumulates in the occipital cortices; however, it draws less attention. We investigated the clinical implications of Aß accumulation in the occipital lobes in the Alzheimer's disease (AD) continuum. [18F]-Florbetaben amyloid PET scans were performed in a total of 121 AD or amnestic mild cognitive impairment (aMCI) patients. Of the 121 patients, 74 Aß positive patients were divided into occipital Aß positive (OCC+) and occipital Aß negative (OCC-) groups based on Aß accumulation in the bilateral occipital lobes. The OCC+ group (41/74, 55.4%) was younger and had a younger age at onset than the OCC- group. The OCC+ group also had an increased standard uptake value ratio in the occipital lobes and greater cortical thinning in relevant areas. The OCC+ group had a higher global deterioration scale, lower performance for the copy, immediate recall, delayed recall, and recognition in Rey-Osterrieth Complex Figure tests than the OCC- group, although both groups had similar disease durations. AD or aMCI patients in the OCC+ group exhibited features noted in early onset AD with relevant neuropsychological and image findings. Occipital Aß positivity in amyloid PET scans need to be considered as an underestimated marker of early onset AD continuum.

Observation of vibronic emission spectrum of jet-cooled 3,5-difluorobenzyl radical.

We applied the technique of corona-excited supersonic expansion using a pinhole-type glass nozzle to observe the vibronic emission spectrum of jet-cooled benzyl-type radicals from the corona discharge of precursor 3,5-difluorotoluene seeded in a large amount of inert helium carrier gas. The vibronically well-resolved emission spectrum was recorded with a long-path monochromator in the visible region. After subtracting the vibronic bands originating from isomeric difluorobenzyl radicals from the observed spectrum, we identified for the first time the bands belonging to the 3,5-difluorobenzyl radical, from which the electronic energy and vibrational mode frequencies of the 3,5-difluorobenzyl radical were accurately determined in the ground electronic state by comparison with those of the precursor and with those from an ab initio calculation.

Analgesic Tolerance Development during Repetitive Electric Stimulations Is Associated with Changes in the Expression of Activated Microglia in Rats with Osteoarthritis.

Electric stimulation is used for managing osteoarthritic (OA) pain; however, little is known about the development of analgesic tolerance during repeated stimulations and the relation of spinal microglia with OA pain. We investigated the changes in the analgesic effects of repeated electric stimulations and the relation between the development of analgesic tolerance and spinal microglial expression in rats with OA. To induce OA, monosodium iodoacetate was injected into the synovial space of the right knee joint of the rats (n = 185). Repeated high frequency, low frequency, or sham transcutaneous electric nerve stimulation (TENS) was performed to the ipsilateral knee joint for 20 min in rats with OA (n = 45). Minocycline or minocycline plus TENS (HF, LF, or sham) was treated in OA rats with repeated TENS-induced tolerance (n = 135). Immunohistochemistry of the microglia in the L3-L5 spinal segments was performed. Knee joint pain during passive movement of the knee joint were quantified using the knee-bend score and the proportion of activated microglia was calculated as primary variables. Paw withdrawal threshold (hypersensitivity to mechanical stimuli) was assessed and the resting and activated microglia were counted as secondary variables. Repeated applications decreased the analgesic effect of TENS on OA pain and failed to reduce the expression of activated microglia in the spinal cord. However, spinal microglial inhibition by minocycline restored the analgesic effect of TENS on OA pain in TENS-tolerant OA rats. TENS combined with minocycline treatment improved knee joint pain and mechanical hypersensitivity in TENS-tolerant OA rats, and inhibited the expression of activated microglia in the spinal cord. These results suggest a possible relationship between repetitive electric stimulation-induced analgesic tolerance for OA pain control and changes in microglia activation.

Alterations in protein expression patterns of spinal peroxisome proliferator-activated receptors after spinal cord injury.

Objectives: Peroxisome proliferator-activated receptors (PPARs) control wound healing processes in damaged tissues. PPAR agonists have neuroprotective effects in spinal cord injury (SCI); however, isotype-specific roles of PPARs are not well understood. Therefore, we evaluated protein expression changes for three isotypes of PPARs at different time points and locations relative to the epicenter after SCI in rats. Methods: A 10-g rod was dropped on the spinal cord which located at the T10 vertebra of rats from a height of 6.25, 12.5, or 50 mm using New York University impactor. We collected the spinal cord at 6, 12, 24, and 72 h and 1, 3, and 5 weeks after SCI. The protein expression of PPARs was analyzed using western blot. Results: The protein expression of PPAR-α declined gradually up to 5 weeks at the epicenter. PPAR-ß/δ expression increased from 3 days to 5 weeks at the caudal region, but decreased at the epicenter in the severe injury group. PPAR-γ expression increased significantly at all regions in all three injury groups up to 5 weeks after SCI and increased to a greater extent in the severe injury group. In addition, PPAR-ß/δ controlled protein expression of PPAR-α positively, and -γ negatively. Conclusions: The present results suggest that different PPAR isotypes have varied protein expression patterns at the epicenter and in adjacent regions after SCI. Our results suggest that PPARs may have overlapping but distinct roles. These findings will be useful for further studies investigating PPARs in neurological disorders including SCI.

Transcutaneous Electrical Nerve Stimulation Reduces Knee Osteoarthritic Pain by Inhibiting Spinal Glial Cells in Rats.

BACKGROUND: Transcutaneous electrical nerve stimulation (TENS) is commonly used for pain control. However, the effects of TENS on osteoarthritis (OA) pain and potential underlying mechanisms remain unclear. OBJECTIVE: The objective of this study was to investigate the effect of TENS on OA pain treatment and underlying mechanisms related to glial cell inhibition. DESIGN: This was an experimental study. METHODS: OA was induced by injection of monosodium iodoacetate into the synovial space of the right knee joint of rats. High-frequency (HF) TENS (100 Hz), low-frequency (LF) TENS (4 Hz), or sham TENS was applied to the ipsilateral knee joint for 20 minutes. Paw withdrawal threshold (PWT), weight bearing, and knee bend score (KBS) were measured. Immunohistochemistry for microglia and astrocytes was performed with L3 to L5 spinal segment samples. To investigate the effects of glial inhibition on OA pain, minocycline, l-α-aminoadipate, or artificial cerebrospinal fluid was injected intrathecally, and PWT and KBS were measured. RESULTS: Compared with sham TENS, both HF TENS and LF TENS significantly increased PWT, decreased KBS, and inhibited activated microglia in the L3 to L5 segments but did not decrease the total number of microglia, except in the L4 segment (HF TENS). Astrocyte expression was significantly decreased in the L3 to L5 segments following LF TENS and in the L3 segment following HF TENS. Compared with artificial cerebrospinal fluid, both minocycline and l-α-aminoadipate increased PWT and decreased KBS. LIMITATIONS: These results cannot be generalized to humans. CONCLUSIONS: TENS alleviates OA pain in rats by inhibiting activated microglia and reducing astrocyte expression in the spinal cord. Although these results may not be generalizable to chronic pain in patients with OA, within the limitation of the experimental animal model used in the present study, they suggest a possible mechanism and preclinical evidence supporting further experimentation or clinical use of TENS in humans.

The peripheral role of group I metabotropic glutamate receptors on nociceptive behaviors in rats with knee joint inflammation.

We examined whether the mGluR1 and mGluR5 were involved in development and maintenance of behavioral signs of non-evoked pain and secondary mechanical hyperalgesia induced by knee joint inflammation. Selective mGluR1 antagonist, (RS)-1-aminoindan-1,5-dicarboxylic acid (AIDA: 50, 100, 200 microM/25 microl, n=10 per group) and selective mGluR5 antagonist, 2-methyl-6-(phenylethynyl)-pyridine (MPEP: 50, 100, 200 nM/25 microl, n=10 per group) was intra-articularly (i.a.) injected 30 min before and 4h after carrageenan injection and behavioral tests were conducted. In the pre-treatment, only a higher dose (200 nM) of MPEP significantly prevented the magnitude of weight load reduction, whereas AIDA (200 microM) and MEPE (50, 100 and 200 nM) significantly reduced the development of mechanical hyperalgesia compared to saline treated group. In the post-treatment, AIDA (200 microM) and MPEP at 100 and 200 nM partially reversed the reduction of weight load induced by carrageenan. MPEP significantly increased the withdrawal threshold to mechanical stimulation in a dose-dependent manner, whereas AIDA had significantly reversed the decreased the paw withdrawal threshold only at 200 microM. The present study demonstrated that i.a. MPEP, selective mGluR5 antagonist is more effective than selective mGluR1 antagonist, AIDA on non-evoked pain as well as mechanical hyperalgesia in both induction and maintenance phase in knee joint inflammation. It is suggested that peripheral mGlu5 receptors play a more prominent role in inflammatory pain including evoked and spontaneous pain. Thus, selective mGluR5 antagonist could be effective therapeutic tools in clinical setting.

Low-Level Laser Irradiation Improves Motor Recovery After Contusive Spinal Cord Injury in Rats.

This study investigated the therapeutic effects of low-level laser irradiation (LLLI) on the recovery of motor function and its underlying mechanisms in rats with spinal cord injury (SCI). The spinal cord was contused at the T11 level using a New York University impactor. Thirty-eight rats were randomly divided into four groups: LLLI with 0.08 J, 0.4 J, 0.8 J, and sham. We transcutaneously applied at the lesion site of the spinal contusive rats 5 min after injury and then daily for 21 days. The Basso, Beattie and Bresnahan (BBB) locomotor scale and combined behavioral score (CBS) were used to evaluate motor function. The spinal segments of rostral and caudal from the lesion site, the epicenter, and L4-5 were collected from normal and the all groups at 7 days after SCI. The expression of tumor necrosis factor-α (TNF-α) and inducible nitric oxide synthase (iNOS) was compared across groups in all regions. In the present study, LLLI with 0.4 J and 0.8 J led to a significant improvement in motor function compared to sham LLLI, which significantly decreased TNF-α expression at the lesion epicenter and reduced iNOS expression in the caudal segment for all LLLI groups and in the L4-5 segments for the 0.4 J and 0.8 J groups when compared to sham LLLI group. Our results demonstrate that transcutaneous LLLI modulate inflammatory mediators to enhance motor function recovery after SCI. Thus, LLLI in acute phase after SCI might have therapeutic potential for neuroprotection and restoration of motor function following SCI.

Characteristics of PCDDs/PCDFs in stack gas from medical waste incinerators.

Toxic polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in 45 stack gas samples were measured from 19 medical waste incinerators in South Korea using high-resolution gas chromatography equipped with a high-resolution mass spectrometer. The average concentrations of the sum of 17 toxic PCDD/PCDF congeners emitted from the medical waste incinerators ranged from 0.153 to 101.9 ng/Sm3. Based on the World Health Organization toxic equivalency factor, they ranged from 0.007 to 5.437 ng-TEQ/Sm3. The congener patterns of PCDDs/PCDFs were described using principal component analysis and presented four patterns. In the evaluation of annual average total TEQ concentrations, outlying stack gas samples were excluded. In this study, the number of chlorine substitutions was evaluated as an important factor in congener patterns. Coefficient of determination values were employed for evaluation of correlation between PCDDs and PCDFs. 1,2,3,4,6,7,8-HpCDF was measured as the most emitted congener, while 2,3,4,7,8-PeCDF was the greatest TEQ contributor.