Deep-computer-generated holography with temporal-focusing and a digital propagation matrix for rapid 3D multiphoton stimulation.

Deep learning-based computer-generated holography (DeepCGH) has the ability to generate three-dimensional multiphoton stimulation nearly 1,000 times faster than conventional CGH approaches such as the Gerchberg-Saxton (GS) iterative algorithm. However, existing DeepCGH methods cannot achieve axial confinement at the several-micron scale. Moreover, they suffer from an extended inference time as the number of stimulation locations at different depths (i.e., the number of input layers in the neural network) increases. Accordingly, this study proposes an unsupervised U-Net DeepCGH model enhanced with temporal focusing (TF), which currently achieves an axial resolution of around 5 µm. The proposed model employs a digital propagation matrix (DPM) in the data preprocessing stage, which enables stimulation at arbitrary depth locations and reduces the computation time by more than 35%. Through physical constraint learning using an improved loss function related to the TF excitation efficiency, the axial resolution and excitation intensity of the proposed TF-DeepCGH with DPM rival that of the optimal GS with TF method but with a greatly increased computational efficiency.

Optimal tooth sectioning using a surgical handpiece and elevator: a finite element study of horizontally deeply impacted mandibular third molars.

OBJECTIVES: To conduct a finite element analysis of the impact of different variables on tooth sectioning efficiency and trauma to surrounding tissues when utilizing high-speed surgical handpieces and elevators. METHODS: CBCT data from the horizontally impacted third mandibular molar (M3M) of a patient were utilized to establish digital models of the M3M, adjacent M2M, and surrounding bone. To simulate tooth sectioning, a 3D finite element model was established with the following variables: remaining tooth tissue thickness (1-5 mm), tooth section fissure width (1-3 mm), elevator depth in fissure (2-6 mm), elevator position (buccal, lingual, central), elevator width (2-5 mm), and application of force (rotating, levering). Using this model, the distribution of stress on the M3M and the surrounding tissue was assessed while measuring tooth sectioning efficiency and trauma to the surrounding tissue. RESULTS: Factors associated with uniform stress at the site of sectioning included thin (≤ 3 mm) remaining tooth tissue, appropriate fissure width (~ 2 mm), a wide (≥ 4 mm) elevator, and central elevator positioning. Levering the elevator yielded greater stress on the M3M than rotating force. Greater sectioning efficiency was associated with increased stress placed on the distobuccal side of M2M. CONCLUSIONS: Tooth sectioning efficiency can be improved by adjusting the high-speed surgical handpiece and elevator. However, it is important to remain attentive to the trauma to which adjacent teeth are exposed during this process. CLINICAL SIGNIFICANCE: These results offer guidance for approaches to improving operator efficiency and reducing trauma to surrounding tissues during tooth sectioning.

Palladium-Catalyzed Regiospecific Decarboxylative Allylation of (Cyclohexadienylidene)malononitriles: Access to α-Allyl-α-aryl Malononitriles.

A palladium-catalyzed regiospecific decarboxylative ε-allylation of (cyclohexadienylidene)malononitriles is presented for the synthesis of functionalized α-allyl-α-aryl malononitriles. This reaction proceeds via a resonance-stabilized α-aryl malononitrile anion, resulting in a wide range of α-allyl-α-aryl malononitriles in high yields with excellent linear product selectivity. We have also shown that the resulting products can be transformed into valuable synthetic intermediates by decyanation and Mizoroki-Heck arylation. In addition, an enantioselective decarboxylative allylation reaction is also presented.

Gas1 up-regulation is inducible and contributes to cell apoptosis in reactive astrocytes in the substantia nigra of LPS and MPTP models.

BACKGROUND: Reactive astrogliosis is a remarkable pathogenetic hallmark of the brains of Parkinson's disease (PD) patients, but its progressive fate and regulation mechanisms are poorly understood. In this study, growth arrest specific 1 (Gas1), a tumor growth suppressor oncogene, was identified as a novel modulator of the cell apoptosis of reactive astrocytes in primary culture and the injured substantia nigra. METHODS: Animal models and cell cultures were utilized in the present study. Lipopolysaccharide (LPS)- and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated animal models were used to detect Gas1 expression in the brain via immunohistochemistry and western blot. Cell cultures were performed to analyze Gas1 functions in the viability and apoptosis of reactive astrocytes and SH-SY5Y cells by double labeling, CCK-8, LDH, TUNEL, flow cytometry, and siRNA knockdown methods. RESULTS: Gas1 expressions were significantly elevated in the majority of the reactive astrocytes of the brains with LPS or MPTP insults. In the injured substantia nigras, GFAP-positive astrocytes exhibited higher levels of cleaved caspase-3. In cell culture, the up-regulated Gas1 expression induced apoptosis of reactive astrocytes that were insulted by LPS in combination with interferon-γ and tumor necrosis factor-a. This effect was confirmed through siRNA knockdown of Gas1 gene expression. Finally and interestingly, the potential underlying signaling pathways were evidently related to an increase in the Bax/Bcl-2 ratio, the abundant generation of reactive oxygen species and the activation of cleaved caspase-3. CONCLUSIONS: This study demonstrated that the up-regulation of inducible Gas1 contributed to the apoptosis of reactive astrocytes in the injured nigra. Gas1 signaling may function as a novel regulator of astrogliosis and is thus a potential intervention target for inflammatory events in PD conditions.

[The "Yin/Yang" Functional Features of Neurotrophic Factors].

Neurotrophic factor is a kind of protein family that plays an important role in the nutrition, support and differentiation to central neurons as well as synaptic plasticity. Growing evidences have revealed that pro-forms of various neurotrophic factors, which are generated in process of protein synthesis and might exert opposite roles involving in inducement of neuronal apoptosis and implication in pathogenesis of neurodegenerative diseases. This paper reviews "Yin/Yang" features of neurotrophic factors in the anabolism, receptor regulation, functional aspects, and their related role in pathogenesis of neurodegenerative diseases. It is hopefully to provide new idea on understanding and investigation of the neurotrophic factors regarding on their functional, pathological and potential therapeutic significance.

Brain-derived neurotrophic factor stimulates proliferation and differentiation of neural stem cells, possibly by triggering the Wnt/ß-catenin signaling pathway.

Brain-derived neurotrophic factor (BDNF) has critical functions in promoting survival, expansion, and differentiation of neural stem cells (NSCs), but its downstream regulation mechanism is still not fully understood. The role of BDNF in proliferation and differentiation of NSCs through Wnt/ß-catenin signaling was studied via cell culture of cortical NSCs, Western blotting, immunocytochemistry, and TOPgal (Wnt reporter) analysis in mice. First, BDNF stimulated NSC proliferation dose dependently in cultured neurospheres that exhibited BrdU incorporation and neuronal and glial differentiation abilities. Second, BDNF effectively enhanced cell commitment to neuronal and oligodendrocytic fates, as indicated by increased differentiation marker Tuj-1 (neuronal marker), CNPase (oligodendrocyte marker), and neuronal process extension. Third, BDNF upregulated expression of Wnt/ß-catenin signaling (Wnt1 and free ß-catenin) molecules. Moreover, these promoting effects were significantly inhibited by application of IWR1, a Wnt signaling-specific blocker in culture. The TOPgal mouse experiment further confirmed BDNF-triggered Wnt signaling activation by ß-gal labeling. Finally, an MEK inhibition experiment showed a mediating role of the microtubule-associated protein kinase pathway in BDNF-triggered Wnt/ß-catenin signaling cascades. This study overall has revealed that BDNF might contribute to proliferation and neuronal and oligodendrocytic differentiation of NSCs in vitro, most possibly by triggering the Wnt/ß-catenin signaling pathway. Nevertheless, determining the exact cross-talk points at which BDNF might stimulate Wnt/ß-catenin signaling pathway in NSC activity requires further investigation.

Presence of proNGF-sortilin signaling complex in nigral dopamine neurons and its variation in relation to aging, lactacystin and 6-OHDA insults.

Growing evidence has shown that proNGF-p75NTR-sortilin signaling might be a crucial factor in neurodegeneration, but it remains unclear if it may function in nigral neurons under aging and disease. The purpose of this study is to examine and quantify proNGF and sortilin expression in the substantia nigra and dynamic changes of aging in lactacystin and 6-hydroxydopamine (6-OHDA) rat models of Parkinson's disease using immunofluorescence, electronic microscopy, western blot and FLIVO staining methods. The expression of proNGF and sortilin was abundantly and selectively identified in tyrosine hydroxylase (TH)-containing dopamine neurons in the substantia nigra. These proNGF/TH, sortilin/TH-positive neurons were densely distributed in the ventral tier, while they were less distributed in the dorsal tier, where calbindin-D28K-containing neurons were numerously located. A correlated decrease of proNGF, sortilin and TH was also detected during animal aging process. While increase of proNGF, sortilin and cleaved (active) caspase-3 expression was found in the lactacystin model, dynamic proNGF and sortilin changes along with dopamine neuronal loss were demonstrated in the substantia nigra of both the lactacystin and 6-OHDA models. This study has thus revealed the presence of the proNGF-sortilin signaling complex in nigral dopamine neurons and its response to aging, lactacystin and 6-OHDA insults, suggesting that it might contribute to neuronal apoptosis or neurodegeneration during pathogenesis and disease progression of Parkinson's disease; the underlying mechanism and key signaling pathways involved warrant further investigation.

Damage Monitoring of Composite Adhesive Joint Integrity Using Conductivity and Fiber Bragg Grating.

Adhesive joints possess a number of advantages over traditional joining methods and are widely used in composite structures. Conventional non-destructive examination techniques do not readily reveal joint degradation before the formation of explicit defects. Embedded fiber Bragg grating (FBG) sensors and the resistance of carbon nanotube (CNT)-doped conductive joints have been proposed to monitor the structural integrity of adhesive joints. Both techniques will be employed and compared in the current work to monitor damage development in adhesive joints under tensile and cyclic fatigue loading. Most of the previous works took measurements under an applied load, which by itself will affect the monitoring signals without the presence of any damage. Moreover, most FBG works primarily relied on the peak shifting phenomenon for sensing. Degradation of adhesive and inter-facial defects will lead to non-uniform strain that may chirp the FBG spectrum, causing complications in the peak shifting measurement. In view of the above shortfalls, measurements are made at some low and fixed loads to preclude any unwanted effect due to the applied load. The whole FBG spectrum, instead of a single peak, will be used, and a quantitative parameter to describe spectrum changes is proposed for monitoring purposes. The extent of damage is revealed by a fluorescent penetrant and correlated with the monitoring signals. With these refined techniques, we hope to shed some light on the relative merits and limitations of the two techniques.

Surface modification of zirconia ceramics through cold plasma treatment and the graft polymerization of biomolecules.

Background/purpose: Although zirconia ceramics were highly versatile as dental implants, their long-term presence in the human body may slow down healing and impede cell growth in the past. To enhance the cytocompatibility of zirconia ceramics, surface activation modification was used to immobilize biopolymers such that a biomimetic environment was created. Materials and methods: Hexamethyldisilazane thin films were deposited onto the surface of inorganic zirconia through cold plasma treatment under various power and deposition time settings to form an organosilane interface layer. Next, oxygen plasma treatment was performed to activate the free radicals on the surface. Subsequently, ultraviolet light was employed to graft and polymerize acrylic acid for generating carboxyl groups on the surface. This was followed by a condensation reaction with biopolymers (chitosan, chitosan/poly-γ-glutamic acid, and gelatin). Results: Under a 20-min deposition time at 40 W and 150 mTorr, the thin films had a maximum graft density of 2.1 mg/cm2. MG-63 cells (human osteosarcoma cells) were employed to evaluate cell compatibility. Chitosan and chitosan/poly-γ-glutamic acid promoted the compatibility of MG-63 cells (a human osteosarcoma cell line) with zirconia ceramics, whereas gelatin reduced this compatibility. Conclusion: The findings confirm that cold plasma treatment and graft polymerization can promote the immobilization of biomolecules and improve the biocompatibility of zirconia ceramics. This approach can be applied to the modification of zirconia ceramic implants.

Neurokinin receptor 3 peptide exacerbates 6-hydroxydopamine-induced dopaminergic degeneration in rats through JNK pathway.

Neurokinin 3 (NK3) receptor is predominantly expressed in striatum and substantia nigra (SN). Evidences have indicated the roles of NK3 receptor in the pathogenesis of Parkinson's disease. By administrating NK3 receptor agonist senktide into 6-hydroxydopamine (6-OHDA)-lesioned rats, exacerbation of dopaminergic degeneration was found in striatum and substantia nigra pars compacta. From apomorphine rotation test, significant increase of contralateral rotation number was detected in 6-OHDA-lesioned rats with senktide injection. Furthermore, tyrosine hydroxylase expression in striatum and substantia nigra pars compacta were examined by immunohistochemistry and Western blotting. Further reduction of tyrosine hydroxylase immunoreactivities was found in 6-OHDA-lesioned rats that received senktide treatment. Also, phosphorylation of N-methyl-D-aspartate receptor 1 subunit was investigated in SN region and significant up-regulation was revealed in senktide-treated 6-OHDA-lesioned rats. Finally, phosphorylation of mitogen-activated protein kinase c-Jun N-terminal kinase (JNK) and c-Jun were examined in nigral region. Up-regulation of phosphorylated JNK molecules was shown in SN region after senktide injection. In line with this evidence, phosphorylation of c-Jun at Ser 63 and Ser 73 was also up-regulated by senktide treatment, thus presenting new aspects that NK3 peptide could exacerbate 6-OHDA toxicity in in vivo models and the possible mechanism may be contributed by the modulation of N-methyl-D-aspartate receptor 1 subunit and JNK pathway activities.

Programmed Death-1 Deficiency Aggravates Motor Dysfunction in MPTP Model of Parkinson's Disease by Inducing Microglial Activation and Neuroinflammation in Mice.

Abundant reactive gliosis and neuroinflammation are typical pathogenetic hallmarks of brains in Parkinson's disease (PD) patients, but regulation mechanisms are poorly understood. We are interested in role of programmed death-1 (PD-1) in glial reaction, neuroinflammation and neuronal injury in PD pathogenesis. Using PD mouse model and PD-1 knockout (KO) mice, we designed wild-type-control (WT-CON), WT-1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (WT-MPTP), PD-1-KO-control (KO-CON) and PD-1-KO-MPTP (KO-MPTP), and observed motor dysfunction of animal, morphological distribution of PD-1-positive cells, dopaminergic neuronal injury, glial activation and generation of inflammatory cytokines in midbrains by motor behavior detection, immunohistochemistry and western blot. WT-MPTP mouse model exhibited decrease of PD-1/Iba1-positive microglial cells in the substantia nigra compared with WT-CON mice. By comparison of four groups, PD-1 deficiency showed exacerbation in motor dysfunction of animals, decreased expression of TH protein and TH-positive neuronal protrusions. PD-1 deficiency enhanced microglial activation, production of proinflammatory cytokines like inducible nitric oxide synthase, tumor necrosis factor-α, interleukin-1ß and interleukin-6, and expression and phosphorylation of AKT and ERK1/2 in the substantia nigra of MPTP model. We concluded that PD-1 deficiency could aggravate motor dysfunction of MPTP mouse model by inducing microglial activation and neuroinflammation in midbrains, suggesting that PD-1 signaling abnormality might be possibly involved in PD pathogenesis.

The TrkB-positive dopaminergic neurons are less sensitive to MPTP insult in the substantia nigra of adult C57/BL mice.

Tyrosine kinase receptors TrkB and TrkC mediate neuroprotective effects of the brain-derived neurotrophic factor (BDNF) and neurotrophins in the dopaminergic nigro-striatal system, but it is obscure about their responses or expression changes in the injured substantia nigra under Parkinson's disease. In present study, immunofluorescence, Fluoro-Jade staining and laser scanning confocal microscopy were applied to investigate distribution and changes of TrkB and TrkC in the dopamine neurons of the substantia nigra by comparison of control and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model. It revealed that TrkB and TrkC-immunoreactivities were substantially localized in cytoplasm and cell membrane of the substantia nigra neurons of control adults. While neurons double-labeled with tyrosine hydroxylase (TH)/TrkB, or TH/TrkC were distributed in a large numbers in the substantia nigra of controls, they apparently went down at 36.2-65.7% of normal level, respectively following MPTP insult. In MPTP model, cell apoptosis or degeneration of nigral neurons were confirmed by caspase-3 and Fluoro-Jade staining. More interestingly, TH/TrkB-positive neurons survived more in cell numbers in comparison with that of TH/TrkC-positive ones in the MPTP model. This study has indicated that TrkB-containing dopamine neurons are less sensitive in the substantia nigra of MPTP mouse model, suggesting that specific organization of Trks may be involved in neuronal vulnerability to MPTP insult, and BDNF-TrkB signaling may play more important role in protecting dopamine neurons and exhibit therapeutic potential for Parkinson's disease.

Bilateral Cavernous Sinus Dural Arteriovenous Fistulae : The Strategies for Endovascular Treatment.

PURPOSE: Most cavernous sinus dural arteriovenous fistulas (CSDAVF) are unilateral; however, simultaneous bilateral CSDAVFs occasionally may be found. This article reports on 141 patients and compares the angioarchitecture and outcomes of embolization of bilateral CSDAVFs with those of unilateral CSDAVFs, with reference to limited demographics (sex and age) of the patients. METHOD: From January 2010 to February 2018 a total of 141 consecutive patients with CSDAVFs were referred for transvenous embolization. Bilateral CSDAVFs were found in 20 patients (14.2%, with a mean age of 62.2 years). The angioarchitecture of the 141 patients with CSDAVFs were evaluated by conventional cerebral angiography. We compared the angioarchitecture and treatment outcomes of 20 bilateral and 121 unilateral CSDAVFs, and in relation to the patients' sex and age. RESULTS: Female patients significantly dominated the bilateral CSDAVFs (90%, p = 0.043). Bilateral eye symptoms were significantly more common in bilateral CSDAVFs (p = 0.011), with dominant orbital and cavernous symptoms, and showed statistical significance (p = 0.049 and 0.011, respectively). Occlusion of one CSDAVF may significantly decrease the fistula flow of the other untreated side (n = 13, 65%), leading to less coil utilization for embolization in bilateral CSDAVFs (p < 0.001). There was no statistical significance in the occurrence of occlusion of the inferior petrous sinus(s), in pial vein reflux, and treatment outcomes in the unilateral and bilateral CSDAVFs. CONCLUSION: Bilateral CSDAVFs were more dominant in female patients and frequently presented with orbital and cavernous symptoms. Fewer coils were used per lesion in the bilateral CSDAVFs. There was no statistical significance in bilateral and unilateral CSDAVFs in terms of impact of venous drainage, pial vein reflux and treatment outcomes.

Reactive Astrocytes Display Pro-inflammatory Adaptability with Modulation of Notch-PI3K-AKT Signaling Pathway Under Inflammatory Stimulation.

Astrocytes are major glial cells critical in assisting the function of the central nervous system (CNS), but the functional changes and regulation mechanism of reactive astrocytes are still poorly understood in CNS diseases. In this study, mouse primary astrocytes were cultured, and inflammatory insult was performed to observe functional changes in astrocytes and the involvement of Notch-PI3K-AKT signaling activation through immunofluorescence, PCR, Western blot, CCK-8, and inhibition experiments. Notch downstream signal Hes-1 was clearly observed in the astrocytes, and Notch signal inhibitor GSI dose-dependently decreased the cleaved Notch-l level without an influence on cell viability. Inflammatory insult of lipopolysaccharide plus interferon-γ (LPS+IFNγ) induced an increase in pro-inflammatory cytokines, that is, iNOS, IL-1ß, IL-6, and TNF, at the protein and mRNA levels in activated astrocytes, which was reduced or blocked by GSI treatment. The cell viability of the astrocytes did not show significant differences among different groups. While an increase in MyD88, NF-кB, and phosphor-NF-кB was confirmed, upregulation of PI3K, AKT, and phosphor-AKT was observed in the activated astrocytes with LPS+IFNγ insult and was reduced by GSI treatment. Inhibitor experiments showed that inhibition of Notch-PI3K-AKT signaling activation reduced the pro-inflammatory cytokine production triggered by LPS+IFNγ inflammatory insult. This study showed that the reactive astrocytes displayed pro-inflammatory adaptability through Notch-PI3K-AKT signaling activation in response to inflammatory stimulation, suggesting that the Notch-PI3K-AKT pathway in reactive astrocytes may serve as a promising target against CNS inflammatory disorders.

Reactive astrocytes increase expression of proNGF in the mouse model of contused spinal cord injury.

Astrocytes are major glial cells critically in maintaining stability of the central nervous system and functional activation of astrocytes occurs rapidly in various diseased or traumatic events. We are interested in functional changes of astrocytes during the spinal cord injury, and studied expression of nerve growth factor (NGF) in activated astrocytes by mouse model of contused spinal cord injury and cell culture experiment. It revealed that the spinal cord injury resulted in apparent activation of astrocytes and microglial cells and decreased BMS scores. A larger number of astrocytes showed immunoreactivity to proNGF in the injured spinal cord areas, and proNGF expression increased and remained high level at 7 to 14dpi, which was coincided with upregulation of glial fibrillary acidic protein. The proNGF was clearly localized in both exosome-like vesicles and cytoplasm of astrocytes in culture. Electron microscopy confirmed exosome-like vesicles with proNGF-immunoreactivity in diameter sizes of 50-100 nm. Finally, cell culture with lipopolysaccharide (LPS) experiment indicated increasing expression and release of proNGF in the astrocytes with LPS exposure. This study demonstrated that reactive astrocytes increased proNGF expression after spinal cord injury, also suggesting involvement of exosome-like proNGF transport or release in triggering neuronal apoptosis and aggravating progression of spinal cord injury.

Up-regulation of D-serine might induce GABAergic neuronal degeneration in the cerebral cortex and hippocampus in the mouse pilocarpine model of epilepsy.

Epilepsy is a serious neurological disorder with neuronal loss and spontaneous recurrent seizures, but the neurochemical basis remains largely unclear. We hypothesize that D-serine, a newly identified endogenous co-agonist of N-methyl-D-aspartate (NMDA) receptor, may trigger excitotoxicity and neuronal damage in epileptogenesis. By using a mouse pilocarpine model, immunohistochemistry, Fluoro-Jade staining and double-labeling, the present study revealed up-regulation of D-serine expression in a proportion (41%) of neurons in the cerebral cortex and hippocampus. The D-serine-positive neurons occurred at 4 h, reached peak levels at 12-24 h, and gradually went down at 3-14 days. Moreover, most of D-serine-positive neurons were GABAergic (98%), underwent degenerating death (93%), and were accompanied enhancing phosphorylation of NMDA receptor subunit 1. This study has provided new evidence that up-regulation of D-serine production might induce GABAergic neuronal degeneration through excitotoxic mechanism in the pilocarpine model and may be involved in early pathogenesis and recurrent seizure of chronic epilepsy.

Fluoroscopic angiography quantifies delay in cerebral circulation time and requires less radiation in carotid stenosis patients: A pilot study.

BACKGROUND: Quantitative digital subtraction angiography (DSA) facilitates in-room assessment of flow changes in various cerebrovascular diseases and improves patient safety. The purpose of this study was to compare the diagnostic accuracy of quantitative fluoroscopic angiography (FA) and DSA. METHODS: Twenty-two patients with >70% carotid stenosis according to NASCET criteria were prospectively included in the study. All patients received DSA and FA (ArtisZee, Siemens Healthcare, Forchheim, Germany) before and after carotid stenting in the same angiosuite. The regions of interest (ROIs) included the extracranial internal carotid artery (eICA), first segment of the middle cerebral artery (MCA1), and sigmoid sinus in the anterior-posterior view; cavernous portion of the ICA (cICA), parietal vein, and jugular vein in the lateral views. The time-to-peak (TTP) for all ROIs and cerebral circulation time (CCT) were measured from FA and DSA scans. TTP, CCT, and radiation doses from DSA were compared with those from FA. RESULTS: The mean age of the patients were 69 ± 9.5 years old. The average stenosis was 89.7% ± 7.8% before stenting and 31% ± 3.6% after stenting. No patient suffered from periprocedural stroke. The intermethod correlation for TTP for all ROIs except the eICA and cICA ranged from 0.46 to 0.65 before stenting and 0.57 to 0.73 after stenting, and that for CCT was 0.65 before stenting and 0.57 after stenting. The radiation doses were significantly lower for FA than for DSA regardless of views or periprocedural timing (p < 0.001). CONCLUSION: Stenosis facilitated the creation of a bolus by manual injection and therefore increased the accuracy of cerebral flow quantification in FA. Cerebral hemodynamic assessment by FA is quicker and associated with less radiation.

Neurokinin-3 peptide instead of neurokinin-1 synergistically exacerbates kainic acid-inducing degeneration of neurons in the substantia nigra of mice.

Neurokinin peptides neurokinin-1 (NK1), neurokinin-3 (NK3), and related receptors are abundantly distributed in the substantia nigra (SN) and evidenced by their possible roles in the Parkinson's disease. Differential intervention roles of NK3 on kainic acid (KA)-induced neuronal injury in the SN of mice were thus in vitro and in vivo studied by Fluoro-Jade C (FJC) staining, immunohistochemistry to tyrosine hydroxylase (TH) or phospho-NMDA receptor, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. It revealed that (i) in contrast to protective effect of NK1 agonist septide that reduced FJC-positive degenerative neurons and lesion volume insulted by KA, NK3 agonist senktide significantly increased FJC-positive ones and lesion volume, and this effect was sufficiently reversed by NK3 antagonist SB218795; (ii) similarly, senktide reduced TH-positive neurons and this effect was antagonized by SB218795, but septide increased TH-positive ones; (iii) mechanistic observation showed differential influences of NK1 and NK3 agonists on phosphorylated-NMDA receptor subunit 1 (phospho-NMDAR1) and glial fibrillary acidic protein-expressing astrocytes, i.e. senktide enhanced of NMDA receptor phosphorylation and astrocyte activity, while septide reduced NMDA receptor phosphorylation and astrocytic response; (iv) cell culture further confirmed the exacerbating effect of NK3 agonist on KA-induced lesion of nigral cells or dopaminergic neurons, in which administration of senktide alone did not show significant cell toxicity. This study presents new evidence that neurokinin NK3 instead of NK1 synergistically exacerbate excitotoxic neuronal degeneration in the SN in a dose-dependent manner and possibly through modulation of NMDA receptor phosphorylation and astrocyte activity, suggesting their potential significance in novel pharmaceutical therapy against Parkinson's disease.

Identification and kainic acid-induced up-regulation of low-affinity p75 neurotrophin receptor (p75NTR) in the nigral dopamine neurons of adult rats.

Parkinson's disease is a common and severe debilitating neurological disease that results from massive and progressive degenerative death of dopamine neurons in the substantia nigra, but the mechanisms of neuronal degeneration and disease progression remains largely obscure. We are interested in possible implications of low-affinity p75 neurotrophin receptor (p75NTR), which may mediate neuronal apoptosis in the central nervous system, in triggering cell death of the nigral dopamine neurons. The RT-PCR and immunohistochemistry were carried out to detect if p75NTR is expressed in these nigral neurons and up-regulated by kainic acid (KA) insult in adult rats. It revealed p75NTR-positive immunoreactivity in the substantia nigra, and co-localization of p75NTR and tyrosine hydroxylase (TH) was found in a large number of substantia nigra neurons beside confirmation of p75NTR in the choline acetyltransferase (ChAT)-positive forebrain neurons. Cell count data further indicated that about 47-100% of TH-positive nigral neurons and 98-100% of ChAT-positive forebrain neurons express p75NTR. More interestingly, significant increasing in both p75NTR mRNA and p75NTR-positive neurons occurred rapidly following KA insult in the substantia nigra of animal model. The present study has provided first evidence on p75NTR expression and KA-inducing p75NTR up-regulation in substantia nigra neurons in rodent animals. Taken together with previous data on p75NTR functions in neuronal apoptosis, this study also suggests that p75NTR may play important roles in neuronal cell survival or excitotoxic degeneration of dopamine neurons in the substantia nigra in pathogenesis of Parkinson's disease in human beings.

Nestin small interfering RNA (siRNA) reduces cell growth in cultured astrocytoma cells.

Nestin is an embryonic intermediate filament that transiently expressed in the neural stem/progenitor cells in the developing central nervous system (CNS). Growing evidence has shown that abundant expression of nestin also occurs in both pathological glial-derived tumor cells and reactive astrocytes in various CNS injuries, implying that nestin may play a crucial role in cell growth or proliferation of astrocyte-derived tumor cells. In the present study, we have investigated the possible role of nestin expression in cell growth or survival of CNS tumor cells by using novel small interfering RNA (siRNA) method in cell culture of rat astrocytoma C6 cell line. The nestin expression and cell growth of the cultured astrocytoma cells were examined after nestin siRNA duplex was delivered by cell transfection for 6 h and cell culture was maintained for 48 h. It revealed an effective suppression influence of nestin siRNA on cell growth of cultured astrocytoma cells in a dose-dependent manner. Quantitative data analysis showed that the doses of nestin siRNA at 30-120 nM significantly decreased both cell numbers and expression levels of nestin mRNA and protein. The nestin siRNA also suppressed expression of cellular glial fibrillary acid protein but showed no obvious influence on expression level of Ki-67 protein (a cell proliferation marker). This study has provided in vitro evidence that nestin siRNA can effectively block nestin expression and reduce cell growth of the cultured C6 astrocytoma cells, strongly suggesting that nestin siRNA-induced suppression of tumor cell growth may provide a potential novel clinical therapy against CNS astroglioma events.