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1.
Clin Exp Dermatol ; 43(7): 798-805, 2018 Oct.
Article in English | MEDLINE | ID: mdl-29740850

ABSTRACT

BACKGROUND: Artemisia scoparia Waldst. et Kitaib (AS) (Oriental wormwood, known as Bissuk in Korea) is a plant used in cosmetic and pharmaceutical treatments. However, the effect of AS on atopic dermatitis (AD) has not been described. AIM: To examine the inhibitory effect of AS on AD using a murine model. METHODS: We applied either AS, the butanol-extracted fraction of AS (Bu-OH) or 3,5-dicaffeoyl-epi-quinic acid (DEQA, a major component of Bu-OH) topically for 3 weeks to 2,4-dinitrofluorobenzene (DNFB)-induced skin lesions in BALB/c mice. RESULTS: AS, Bu-OH and DEQA suppressed the clinical symptoms of DNFB-induced skin lesions and he associated scratching behaviour. Numbers of inflammatory cells infiltrating skin lesions were significantly reduced by AS or Bu-OH application but not by DEQA. In addition, AS significantly suppressed serum levels of histamine and IgE, while Bu-OH significantly suppressed serum levels of histamine, IgE, thymic stromal lymphopoietin (TSLP), interleukin (IL)-4 and IL-6, and DEQA significantly suppressed serum levels of histamine, IgE, TSLP and IL-4 in DNFB-induced AD mice. In skin lesions, AS and Bu-OH significantly reduced inflammatory cytokines, whereas DEQA did not. AS, Bu-OH and DEQA all significantly suppressed caspase-1 activities. CONCLUSIONS: These results demonstrate the anti-AD effects of AS, Bu-OH and DEQA, and suggest that all three have therapeutic potential.


Subject(s)
Artemisia , Caspase 1/metabolism , Chlorogenic Acid/analogs & derivatives , Dermatitis, Atopic/drug therapy , Phytotherapy , Plant Extracts/therapeutic use , Administration, Topical , Animals , Caspase 1/genetics , Chlorogenic Acid/therapeutic use , Dermatitis, Atopic/chemically induced , Dermatitis, Atopic/metabolism , Dermatitis, Atopic/pathology , Dinitrofluorobenzene , Disease Models, Animal , Medicine, Korean Traditional , Mice , Mice, Inbred BALB C , RNA, Messenger/metabolism , Skin/pathology
2.
Clin Neuroradiol ; 25(4): 415-8, 2015 Dec.
Article in English | MEDLINE | ID: mdl-25373351

ABSTRACT

Central nervous system (CNS) involvement of scrub typhus infection is well known. Most CNS involvement of scrub typhus infection present as meningitis or encephalitis. We report on a patient suffering from hemorrhagic transformation of intracranial lesions caused by Orientia tsutsugamushi. A 53-year-old female farmer who was infected by scrub typhus was treated with doxycycline and recovered from the systemic illness. However, headache persisted. Brain radiologic studies revealed acute intracranial hemorrhage and enhancing lesion, which implied a CNS involvement. Hemorrhagic transformation of encephalitis by scrub typhus is very rare complication and to our best knowledge, this is the first report of hemorrhagic transformation of scrub typhus encephalitis. Clinician should consider the possibility of hemorrhagic transformation of encephalitis in cases of scrub typhus infection.


Subject(s)
Cerebral Hemorrhage/diagnosis , Cerebral Hemorrhage/etiology , Infectious Encephalitis/complications , Infectious Encephalitis/diagnosis , Scrub Typhus/complications , Scrub Typhus/diagnosis , Cerebral Hemorrhage/therapy , Diagnosis, Differential , Fatal Outcome , Female , Humans , Infectious Encephalitis/therapy , Magnetic Resonance Imaging/methods , Middle Aged , Rare Diseases/diagnosis , Rare Diseases/etiology , Rare Diseases/therapy , Scrub Typhus/therapy , Tomography, X-Ray Computed/methods
3.
Phys Rev Lett ; 112(24): 241101, 2014 Jun 20.
Article in English | MEDLINE | ID: mdl-24996078

ABSTRACT

We report results from the BICEP2 experiment, a cosmic microwave background (CMB) polarimeter specifically designed to search for the signal of inflationary gravitational waves in the B-mode power spectrum around ℓ∼80. The telescope comprised a 26 cm aperture all-cold refracting optical system equipped with a focal plane of 512 antenna coupled transition edge sensor 150 GHz bolometers each with temperature sensitivity of ≈300 µK(CMB)√s. BICEP2 observed from the South Pole for three seasons from 2010 to 2012. A low-foreground region of sky with an effective area of 380 square deg was observed to a depth of 87 nK deg in Stokes Q and U. In this paper we describe the observations, data reduction, maps, simulations, and results. We find an excess of B-mode power over the base lensed-ΛCDM expectation in the range 30 < ℓ < 150, inconsistent with the null hypothesis at a significance of >5σ. Through jackknife tests and simulations based on detailed calibration measurements we show that systematic contamination is much smaller than the observed excess. Cross correlating against WMAP 23 GHz maps we find that Galactic synchrotron makes a negligible contribution to the observed signal. We also examine a number of available models of polarized dust emission and find that at their default parameter values they predict power ∼(5-10)× smaller than the observed excess signal (with no significant cross-correlation with our maps). However, these models are not sufficiently constrained by external public data to exclude the possibility of dust emission bright enough to explain the entire excess signal. Cross correlating BICEP2 against 100 GHz maps from the BICEP1 experiment, the excess signal is confirmed with 3σ significance and its spectral index is found to be consistent with that of the CMB, disfavoring dust at 1.7σ. The observed B-mode power spectrum is well fit by a lensed-ΛCDM+tensor theoretical model with tensor-to-scalar ratio r = 0.20_(-0.05)(+0.07), with r = 0 disfavored at 7.0σ. Accounting for the contribution of foreground, dust will shift this value downward by an amount which will be better constrained with upcoming data sets.

4.
Cell Death Differ ; 19(5): 859-70, 2012 May.
Article in English | MEDLINE | ID: mdl-22095282

ABSTRACT

Protein arginine methylation, catalyzed by protein arginine methyltransferases (PRMTs), is implicated in modulation of cellular processes including gene transcription. The role of PRMTs in the regulation of intracellular signaling pathways has remained obscure, however. We now show that PRMT1 methylates apoptosis signal-regulating kinase 1 (ASK1) at arginine residues 78 and 80 and thereby negatively regulates ASK1 signaling. PRMT1-mediated ASK1 methylation attenuated the H(2)O(2)-induced stimulation of ASK1, with this inhibitory effect of PRMT1 being abolished by replacement of arginines 78 and 80 of ASK1 with lysine. Furthermore, depletion of PRMT1 expression by RNA interference potentiated H(2)O(2)-induced stimulation of ASK1. PRMT1-mediated ASK1 methylation promoted the interaction between ASK1 and its negative regulator thioredoxin, whereas it abrogated the association of ASK1 with its positive regulator TRAF2. Moreover, PRMT1 depletion potentiated paclitaxel-induced ASK1 activation and apoptosis in human breast cancer cells. Together, our results indicate that arginine methylation of ASK1 by PRMT1 contributes to the regulation of stress-induced signaling that controls a variety of cellular events including apoptosis.


Subject(s)
Arginine/metabolism , MAP Kinase Kinase Kinase 5/metabolism , Protein-Arginine N-Methyltransferases/metabolism , Repressor Proteins/metabolism , Apoptosis/genetics , Apoptosis/physiology , Cell Line , Cell Line, Tumor , Cell Survival/genetics , Cell Survival/physiology , Fluorescent Antibody Technique , Humans , Immunoprecipitation , MAP Kinase Kinase Kinase 5/genetics , Methylation , Mutagenesis, Site-Directed , Protein-Arginine N-Methyltransferases/genetics , RNA Interference , Repressor Proteins/genetics
5.
Interv Neuroradiol ; 17(2): 248-51, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21696667

ABSTRACT

We describe the case of a 26-year-old man with orthostatic headache. Cerebral angiography revealed thrombosis in the sagittal sinus. Spine MRI showed cerebrospinal fluid collection at the C1-2 level. We performed blood patch and the symptoms disappeared. We report a rare case of intracranial hypotension caused by CSF leak and describe our hypothesis that SIH can change the velocity of cerebral blood flow and cause thrombosis.


Subject(s)
Cerebral Veins/physiopathology , Cerebrospinal Fluid Rhinorrhea/etiology , Cerebrovascular Circulation/physiology , Intracranial Hypotension/etiology , Sagittal Sinus Thrombosis/complications , Superior Sagittal Sinus/physiopathology , Adult , Cerebral Angiography , Cerebral Veins/diagnostic imaging , Cerebrospinal Fluid Leak , Cerebrospinal Fluid Rhinorrhea/pathology , Cerebrospinal Fluid Rhinorrhea/physiopathology , Humans , Intracranial Hypotension/pathology , Intracranial Hypotension/physiopathology , Magnetic Resonance Imaging , Male , Sagittal Sinus Thrombosis/pathology , Sagittal Sinus Thrombosis/physiopathology , Superior Sagittal Sinus/pathology
6.
J Med Syst ; 34(5): 843-7, 2010 Oct.
Article in English | MEDLINE | ID: mdl-20703625

ABSTRACT

In this study, a high-speed receiver for a capsule endoscope was proposed and implemented. The proposed receiver could receive 20 Mbps data that was sufficient to receive images with a higher resolution than conventional receivers. The receiver used a 1.2 GHz band to receive radio frequency (RF) signal, and demodulated the signal to an intermediate frequency (IF) stage (150 MHz). The demodulated signal was amplified, filtered, and under-sampled by a high-speed analog-to-digital converter (ADC). In order to decode the under-sampled data in real time, a simple frequency detection algorithm was selected and was implemented by using a FPGA. The implemented system could receive 20 Mbps data.


Subject(s)
Analog-Digital Conversion , Capsule Endoscopes , Image Processing, Computer-Assisted/instrumentation , Signal Processing, Computer-Assisted/instrumentation , Telemetry/instrumentation , Equipment Design , Humans
7.
Cell Death Differ ; 14(8): 1518-28, 2007 Aug.
Article in English | MEDLINE | ID: mdl-17541429

ABSTRACT

Gemin5 is a 170-kDa WD-repeat-containing protein that was initially identified as a component of the survival of motor neurons (SMN) complex. We now show that Gemin5 facilitates the activation of apoptosis signal-regulating kinase 1 (ASK1) and downstream signaling. Gemin5 physically interacted with ASK1 as well as with the downstream kinases SEK1 and c-Jun NH(2)-terminal kinase (JNK1), and it potentiated the H(2)O(2)-induced activation of each of these kinases in intact cells. Moreover, Gemin5 promoted the binding of ASK1 to SEK1 and to JNK1, as well as the ASK1-induced activation of JNK1. In comparison, Gemin5 did not physically associate with MKK7, MKK3, MKK6, or p38. Furthermore, depletion of endogenous Gemin5 by RNA interference (RNAi) revealed that Gemin5 contributes to the activation of ASK1 and JNK1, and to apoptosis induced by H(2)O(2) and tumor necrosis factor-alpha (TNFalpha) in HeLa cells. Together, our results suggest that Gemin5 functions as a scaffold protein for the ASK1-JNK1 signaling module and thereby potentiates ASK1-mediated signaling events.


Subject(s)
MAP Kinase Kinase Kinase 5/metabolism , Mitogen-Activated Protein Kinase 8/metabolism , Ribonucleoproteins, Small Nuclear/metabolism , Apoptosis/drug effects , Apoptosis/physiology , Base Sequence , Cell Line , DNA, Complementary/genetics , HeLa Cells , Humans , Hydrogen Peroxide/pharmacology , In Vitro Techniques , MAP Kinase Kinase Kinase 5/genetics , Mitogen-Activated Protein Kinase 8/genetics , Protein Binding , RNA, Small Interfering/genetics , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Ribonucleoproteins, Small Nuclear/antagonists & inhibitors , Ribonucleoproteins, Small Nuclear/genetics , SMN Complex Proteins , Signal Transduction , Transfection , Tumor Necrosis Factor-alpha/pharmacology
8.
J Infect ; 46(4): 253-5, 2003 May.
Article in English | MEDLINE | ID: mdl-12799155

ABSTRACT

We report a case of patient with Clostridium perfringens septicemia and thrombophlebitis of the portal vein (pylephlebitis), probably secondary to an initially unrecognized gastric ulcer. The extension of the thrombosis from the superior mesenteric vein to the main portal vein on a repeat CT scan and subsequent partial resolution of the thrombus with antibiotic therapy alone, suggested that Clostridium perfringens bacteremia may have enhanced the formation of thrombus. The coexistence of Clostridium perfringens septicemia and pylephlebitis should prompt a search for intra-abdominal processes as the portal of entry of infection.


Subject(s)
Clostridium Infections/complications , Clostridium perfringens/isolation & purification , Sepsis/microbiology , Thrombophlebitis/complications , Aged , Humans , Male , Portal Vein , Thrombophlebitis/etiology
9.
Brain Res ; 857(1-2): 41-55, 2000 Feb 28.
Article in English | MEDLINE | ID: mdl-10700551

ABSTRACT

The distribution of labeled neurons in the brain and spinal cord was studied after injecting the Bartha strain of pseudorabies virus (PRV) into the sciatic nerve to provide a baseline for studying neural circuitry after spinal cord injury (SCI) and regeneration. Following a single injection of viral particles into the left sciatic nerve, PRV labeling was found in the spinal cord at 2 days post-injection (p.i.). Increasing complexity in viral labeling from the spinal cord to supraspinal regions became apparent with increasing survival time. In brain regions, several neuronal groups that regulate sympathetic outflow, such as the rostroventrolateral medulla, the lateral paragigantocellular nuclei, and the A5 cells, were densely labeled. However, relatively sparse labeling was noticed in the lateral vestibular nuclei, the red nucleus and the motor cortex whose spinal projections regulate somatic motor function, although those areas were abundantly labeled with Fast blue (FB) in a double-labeling experiment in which FB was co-injected into the lumbar cord. The pattern of viral labeling became more complex beyond 5 days p.i. when increased numbers of cell groups were labeled with PRV but not FB. In addition, some infected neurons started to lyse, as evidenced by a decrease in viral labeling at 7 days p.i. Thus, the 5th day post-viral injection would appear to be an appropriate survival time to obtain maximal labeling with acceptable specificity. We suggest that transneuronal labeling using PRV should be appropriate for studying multi-neural circuitry after SCI and regeneration.


Subject(s)
Axonal Transport/physiology , Cell Communication/physiology , Central Nervous System/cytology , Herpesvirus 1, Suid/immunology , Neural Pathways/cytology , Neurons/cytology , Sciatic Nerve/cytology , Amidines , Animals , Cell Count , Diencephalon/cytology , Female , Fluorescent Dyes , Immunohistochemistry , Medulla Oblongata/cytology , Mesencephalon/cytology , Neurons/virology , Pons/cytology , Rats , Rats, Inbred F344 , Rhizotomy , Spinal Nerve Roots/surgery , Telencephalon/cytology , Time Factors
10.
Reprod Fertil Dev ; 12(3-4): 133-9, 2000.
Article in English | MEDLINE | ID: mdl-11302422

ABSTRACT

The development of porcine oocytes from large (3.1-8.0 mm in diameter) or small (<3.1 mm) follicles was examined after maturation culture in medium containing porcine follicular fluid (pFF). Large follicles yielded larger (256 microm v. 221 microm; P<0.05) cumulus-oocyte complexes and more (22 v. 14%) morphologically normal oocytes than small follicles (Experiment 1). In Experiments 2-4, maturation media supplemented with mixed pFF (10%) from small and large follicles was used. More oocytes from large follicles matured (58% v. 91%), formed pronuclei (81% v. 90%) and developed to the blastocyst stage (2% v. 10%) than oocytes from small follicles. In Experiments 5-7, the effects of pFF collected from either small or large follicles on oocyte development were examined. Regardless of the source of oocytes, large-follicle-derived pFF more significantly enhanced preimplantation development than did small-follicle-derived pFF. The highest rate of blastocyst formation (16%) was found when oocytes from large follicles were cultured in maturation medium containing large-follicle-derived pFF. These results suggest that oocytes from large follicles have greater developmental potential than oocytes from small follicles, and that the origin of pFF, which is added to the maturation media, might be an important factor for improving in vitro development of porcine oocytes.


Subject(s)
Oocytes/growth & development , Ovarian Follicle/cytology , Ovarian Follicle/physiology , Animals , Culture Media , Female , Follicular Fluid/physiology , In Vitro Techniques , Swine
11.
Neuroscience ; 87(4): 807-15, 1998 Dec.
Article in English | MEDLINE | ID: mdl-9759968

ABSTRACT

The effect of picrotoxinin on glycine-induced chloride currents was studied in dissociated rat hippocampal neuron culture in whole-cell and excised outside-out patches. Picrotoxinin blocked the glycine induced chloride currents. The picrotoxinin effect at 20 microM on glycine dose response relationship suggested a competitive mechanism. However, at 1 mM, the picrotoxinin effect was largely noncompetitive. In excised patches, glycine activated two types of channels distinguished by a difference in conductances. The first group had single channel conductances of around 47 pS and another around 100 pS. Occasionally, both types of channels were found in the same excised patch. Low concentration of picrotoxinin selectively blocked large conductance channels. At higher concentrations of 0.5 to 1 mM, picrotoxinin blocked the small conductance channels by a flickering block. These findings indicate that the whole-cell glycine current in rat hippocampal neurons is mediated by at least two types of channels. The two types of channels have distinct conductance, picrotoxinin sensitivity and different mechanism of picrotoxinin block.


Subject(s)
Chloride Channels/antagonists & inhibitors , Chlorides/metabolism , GABA Antagonists/pharmacology , Hippocampus/cytology , Nerve Tissue Proteins/drug effects , Neurons/drug effects , Picrotoxin/analogs & derivatives , Receptors, Glycine/drug effects , Action Potentials/drug effects , Animals , Chloride Channels/chemistry , Hippocampus/drug effects , Ion Transport/drug effects , Ionophores/pharmacology , Nerve Tissue Proteins/metabolism , Patch-Clamp Techniques , Picrotoxin/pharmacology , Rats , Rats, Sprague-Dawley , Receptors, Glycine/metabolism , Sesterterpenes
12.
Neurosurgery ; 42(4): 843-9, 1998 Apr.
Article in English | MEDLINE | ID: mdl-9574649

ABSTRACT

OBJECTIVE: Hyperthermia has been clinically applied to some types of brain tumors. However, the detailed mechanisms of this growth inhibition are not clear. The effect of mild hyperthermia on cultured human glioblastoma cell line, A172, was studied. METHODS: A172 cells were heat treated (43-44.5 degrees C) for 1 hour in the growing phase. Cell viability was assessed by trypan blue dye exclusion assay. The presence of apoptosis was determined by the morphological changes observed using phase contrast microscopy and nuclear changes observed using HOECHST 33342 stain. For the evaluation of cellular deoxyribonucleic acid fragmentation, the TUNEL method was used. The expression of p53 and bax proteins was evaluated by Western blot, and the bax messenger ribonucleic acid was detected by Northern blot. RESULTS: Heat treatment induced cell death in time- and temperature-dependent manners. The nuclear staining with HOECHST 33342 demonstrated morphological changes consistent with apoptosis. The TUNEL stain also demonstrated damages in the deoxyribonucleic acid. These morphological changes were accompanied by the accumulation of p53 protein, bax protein, and messenger ribonucleic acid. CONCLUSION: These results indicate that mild hyperthermia induces apoptosis in A172 glioblastoma cells.


Subject(s)
Apoptosis/physiology , Glioblastoma/physiopathology , Hot Temperature , Proto-Oncogene Proteins c-bcl-2 , Benzimidazoles , Cell Survival/physiology , DNA Fragmentation , Fluorescent Dyes , Glioblastoma/pathology , HSP72 Heat-Shock Proteins , Heat-Shock Proteins/metabolism , Humans , Microscopy, Phase-Contrast , Protein Synthesis Inhibitors/pharmacology , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins/metabolism , RNA/biosynthesis , RNA, Messenger/metabolism , Tumor Cells, Cultured/drug effects , Tumor Suppressor Protein p53/metabolism , bcl-2-Associated X Protein
13.
Bioorg Med Chem ; 6(1): 43-55, 1998 Jan.
Article in English | MEDLINE | ID: mdl-9502104

ABSTRACT

Dihydro-2(3H)-furanones (gamma-butyrolactones) and dihydro-2(3H)-thiophenones (gamma-thiobutyrolactones) containing fluoroalkyl groups at positions C-3, C-4, and C-5 of the heterocyclic rings were prepared. The anticonvulsant/convulsant activities of the compounds were evaluated in mice. Brain concentrations of the compounds were determined and the effects of the compounds on [35S]-tert-butylbicyclophosphorothionate ([35S]TBPS) binding to the picrotoxin site on GABAA receptors were investigated. The effects of the compounds on GABAA receptor function were studied using electrophysiological methods and cultured rat hippocampal neurons. Fluorination at C-3 results in either subtle or pronounced effects on the pharmacological activity of the compounds. When hydrogens are replaced with fluorines at the methylene carbon of an ethyl group, as in 3-(1,1-difluoroethyl)dihydro-3-methyl-2(3H)-furanone (1), the anticonvulsant actions of the compound are not much changed from those found for the corresponding alkyl-substituted analogue. In marked contrast, fluorination at the methyl carbon of the ethyl group, as in dihydro-3-methyl-3-(2,2,2-trifluoroethyl)-2(3H)-furanone (3), produces a compound having convulsant activity. This convulsant activity seems to be due to an increased affinity of the compound for the picrotoxin site on GABAA receptors caused by an interaction that involves the trifluoromethyl group. Results obtained with gamma-butyrolactones containing either a 3-(1-trifluoromethyl)ethyl or a 3-(1-methyl-1-trifluoromethyl)ethyl substituent indicate that the interactions of the trifluoromethyl group with the picrotoxin binding site are subject to both stereochemical and steric constraints. Sulfur for oxygen heteroatom substitution, as in the corresponding gamma-thiobutyrolactones, affects the type (competitive, non-competitive, etc.) of binding interactions that these compounds have with the picrotoxin site in a complex manner. Fluorination of alkyl groups at the C-4 and C-5 positions of gamma-butyrolactones having convulsant activity increases convulsant potency.


Subject(s)
4-Butyrolactone/analogs & derivatives , 4-Butyrolactone/pharmacology , Anticonvulsants/pharmacology , Convulsants/pharmacology , Fluorine Compounds/pharmacology , GABA Modulators/pharmacology , Receptors, GABA-A/drug effects , 4-Butyrolactone/chemical synthesis , Animals , Binding, Competitive , Bridged Bicyclo Compounds, Heterocyclic/metabolism , Cells, Cultured , Electrophysiology , Female , Fluorine Compounds/chemical synthesis , Furans/chemistry , Furans/pharmacology , Hippocampus/drug effects , Mice , Neurons/drug effects , Neurons/metabolism , Picrotoxin/chemistry , Rats , Receptors, GABA-A/chemistry , Receptors, GABA-A/physiology , Structure-Activity Relationship
14.
J Neurotrauma ; 15(2): 141-7, 1998 Feb.
Article in English | MEDLINE | ID: mdl-9512089

ABSTRACT

Indirect glutamate toxicity can be demonstrated by exposing dissociated rat hippocampal cultures to the media of the same culture transiently exposed (1 min) to glutamate (0.5 mM). The toxicity was maximum when the media was collected 5 min after the glutamate exposure. While the primary glutamate toxicity was attenuated by ionotropic glutamate receptor antagonists, the transferred, indirect toxicity was unaffected by the same antagonists. The changes in nuclear morphology indicated chromatin condensation and nuclear fragmentation in both primary and transferred toxicity. The stain for DNA damage by TUNEL method also revealed cells staining positive in both primary and transferred glutamate toxicity. These observations demonstrate that glutamate-induced neurotoxicity can be propagated to the uninjured cells by an unknown toxin released into the extracellular space. This neurotoxin induced both apoptosis and necrosis in cultured rat hippocampal cells.


Subject(s)
Glutamic Acid/poisoning , Hippocampus/drug effects , 6-Cyano-7-nitroquinoxaline-2,3-dione/pharmacology , Animals , Apoptosis/drug effects , Cell Death/physiology , Culture Techniques , DNA Fragmentation , Dizocilpine Maleate/pharmacology , Excitatory Amino Acid Antagonists/pharmacology , Hippocampus/pathology , Hippocampus/physiopathology , Necrosis , Neuroglia/drug effects , Neuroglia/pathology , Neuroprotective Agents/pharmacology , Rats , Rats, Sprague-Dawley
15.
Neuroscience ; 79(4): 999-1004, 1997 Aug.
Article in English | MEDLINE | ID: mdl-9219962

ABSTRACT

A model of in vitro traumatic injury with dissociated rat hippocampal neurons was studied to explore the mechanism of cell death. The neurotoxicity induced by traumatic injury to the cell culture can be transferred to a naive uninjured culture by media exchange. This toxicity is attenuated by dimethylsulfoxide or superoxide dismutase, suggesting that this toxicity is mediated by a free radical generation. Ionotropic glutamate receptor antagonists had no effect. This toxicity was effectively blocked by the pretreatment of the naive uninjured recipient cultures with cycloheximide or with actinomycin D. The DNA fragmentation could be illustrated with in situ nick translation in the cells which seem to have lost their cytoplasm. The nuclear morphology of neurons labeled by a neurofilament-specific antibody, SMI-31, demonstrated chromatin condensation and nucleosome formation. Traumatic injury induces release of an unknown toxin into the extracellular space. These observations suggest that a traumatized neuronal culture can propagate cell death of naive uninjured cells by releasing a neurotoxin that causes apoptosis.


Subject(s)
Apoptosis/physiology , Brain Injuries/pathology , Hippocampus/pathology , Animals , Cells, Cultured , Disease Models, Animal , Rats , Rats, Sprague-Dawley , Wounds and Injuries/pathology
16.
Stroke ; 27(1): 122-6, 1996 Jan.
Article in English | MEDLINE | ID: mdl-8553387

ABSTRACT

BACKGROUND AND PURPOSE: We have previously shown that traumatic injury of hippocampal cells triggers release of a soluble neurotoxin that can be transferred to an uninjured culture. The mechanism of this trauma-induced neurotoxicity is independent of glutamate receptor activation. We extended this observation to study the mechanism of this neurotoxicity. METHODS: Dissociated rat hippocampal neurons were traumatized by disrupting the culture by scratching the plate. The toxicity expressed by the injured culture was studied by transferring the medium to an uninjured culture and assessing the death rate by trypan blue exclusion. RESULTS: This neurotoxin is stable in the medium at room temperature for several hours and withstands boiling. The molecular weight is between 100 and 500. The release and the effect of this toxin seem to be independent of glutamate receptor activation. The toxicity is unaffected by removal of extracellular calcium. However, dantrolene dose-dependently blocked the toxicity in the recipient culture, suggesting that the release of intracellular stores of calcium is involved in the toxic effect. This release of calcium is likely to be followed by an activation of nitric oxide synthase because competitive nitric oxide synthase inhibitors attenuated this toxicity. Consistent with this result, cholecystokinin octapeptide significantly reduced cell death when combined with this toxic medium. CONCLUSIONS: Traumatic injury of dissociated cells can propagate neurotoxicity in uninjured cells by a soluble toxin released into the extracellular space. This toxin causes a rise in cytosolic calcium that activates nitric oxide synthase that can be blocked by cholecystokinin.


Subject(s)
Hippocampus/injuries , Hippocampus/metabolism , Neurons/metabolism , Neurotoxins/metabolism , Animals , Calcium/antagonists & inhibitors , Calcium/metabolism , Calcium/pharmacology , Cell Death/drug effects , Cells, Cultured , Coloring Agents , Cytosol/drug effects , Cytosol/metabolism , Dantrolene/administration & dosage , Dantrolene/pharmacology , Dose-Response Relationship, Drug , Hippocampus/drug effects , Hippocampus/enzymology , Molecular Weight , Neurons/drug effects , Neurons/enzymology , Neuroprotective Agents/pharmacology , Neurotoxins/antagonists & inhibitors , Neurotoxins/chemistry , Nitric Oxide Synthase/antagonists & inhibitors , Nitric Oxide Synthase/metabolism , Rats , Rats, Sprague-Dawley , Receptors, Glutamate/metabolism , Sincalide/pharmacology , Trypan Blue
17.
J Urol ; 154(2 Pt 2): 690-3, 1995 Aug.
Article in English | MEDLINE | ID: mdl-7609156

ABSTRACT

Others have previously demonstrated that the administration of insulin-like growth factor-I accelerates recovery from ischemic acute tubular necrosis in the rat kidney. We investigated the effect of insulin-like growth factor-I on the histology of unilaterally obstructed kidneys in the pouch young of the North American opossum, Didelphis virginiana. In this model complete unilateral ureteral obstruction reliably induces statistically significant degrees of caliceal dilatation, tubular cystic change, and cortical and medullary fibrosis in kidneys examined 1 week after the creation of complete obstruction. Cortical and medullary inflammation is also increased after 1 week of obstruction in this model but not to a degree that is statistically different than control (sham operated) animals. We administered insulin-like growth factor-I to opossum pups with complete unilateral obstruction created at a length of 5 cm. (age 25 days, human equivalent 18 to 20 weeks). Insulin-like growth factor-I (400 mcg/kg.) was injected subcutaneously on the day of operation and again on days 2 and 4 postoperatively. The animals were sacrificed 1 week after obstruction and the formalin fixed, paraffin embedded kidneys were assessed histologically. In the obstructed kidney insulin-like growth factor-I ameliorated the development of fibrosis (cortical and medullary) and caliceal dilatation such that these characteristics did not differ significantly from those of sham operated animals. Tubular cystic change in the obstructed kidneys was also decreased by insulin-like growth factor-I administration but not to significant levels. Insulin-like growth factor-I treatment in obstructed animals resulted in significantly more inflammation (cortical and medullary) than in the sham operated animals. We also administered insulin-like growth factor-I to normal pups with no other intervention. These insulin-like growth factor-I treated pups did not differ from sham pups for any characteristic studied. Our study suggests that there is protective effect of insulin-like growth factor-I on renal architecture when administered in the setting of experimental fetal ureteral obstruction.


Subject(s)
Fetal Diseases/drug therapy , Insulin-Like Growth Factor I/therapeutic use , Ureteral Obstruction/drug therapy , Animals , Insulin-Like Growth Factor I/pharmacology , Kidney/drug effects , Kidney/embryology , Kidney/pathology , Opossums
18.
Neuroscience ; 67(2): 293-300, 1995 Jul.
Article in English | MEDLINE | ID: mdl-7675170

ABSTRACT

The nicotinic antagonists d-tubocurarine and trimethaphan camsylate competitively inhibit GABA-induced currents. Hexamethonium, mecamylamine and dihydro-beta-erythroidine, other nicotinic antagonists, do not affect GABA-elicited currents. The trimethaphan effect is completely reversed by a putative convulsant receptor antagonist, alpha-isopropyl-alpha-methyl-gamma-butyrolactone, which implies that the trimethaphan binding site may be closely associated with the convulsant site. However, nicotine was ineffective in competing for either the d-tubocurarine or trimethaphan effect at the GABAA receptor. From these observations, we propose that the nicotinic and GABAA receptor ionophore complexes share similar configurational patterns that accommodate some of the same molecules. Possible mechanisms for the trimethaphan and d-tubocurarine blockades are discussed.


Subject(s)
GABA Antagonists/pharmacology , Hippocampus/metabolism , Neurons/metabolism , Nicotinic Antagonists/pharmacology , gamma-Aminobutyric Acid/pharmacology , Animals , Cells, Cultured , Electrophysiology , GABA-A Receptor Antagonists , Hippocampus/cytology , Hippocampus/drug effects , Membrane Potentials/drug effects , Molecular Conformation , Neurons/drug effects , Nicotinic Agonists/pharmacology , Patch-Clamp Techniques , Rats , Rats, Sprague-Dawley
19.
Neurosurgery ; 36(5): 1003-7; discussion 1007-8, 1995 May.
Article in English | MEDLINE | ID: mdl-7791963

ABSTRACT

In a rat hippocampal cell culture, we studied the mechanism of adenosine-mediated neuroprotection in traumatic injury to neurons. When the processes and bodies of cells in culture were mechanically disrupted, neurons that were located at a distance from the damage site died. This secondary neuronal death is at least partially mediated by glutamate, because MK801, a specific N-methyl-D-aspartate glutamate channel blocker, diminished the toxic effect. Furthermore, cyclopentyl adenosine, a specific A1 adenosine receptor agonist that specifically attenuates synaptic release at the excitatory terminal, also blocked this trauma-mediated cell death. The dissemination of neurotoxicity from cell injury implies a release of a toxin by the dying cells. Consistent with this hypothesis, we found that neurotoxicity could be transferred to an uninjured neuronal culture by applying extracellular solution of the damaged culture to the healthy undamaged culture, as long as the fluid was transferred within 5 minutes. However, the glutamate concentrations in this medium were never higher than 20 nmol/L, suggesting that glutamate is not mediating the soluble and transferable toxicity. Consistent with this observation, the transferable neurotoxicity was not blocked by MK801 but was effectively blocked by cyclopentyl adenosine. Our observations suggest that traumatic cell death in culture is mediated by multiple mechanisms, including glutamate excitotoxicity.


Subject(s)
Adenosine/agonists , Cell Death , Hippocampus/cytology , Hippocampus/drug effects , Animals , Brain Injuries/pathology , Cell Death/drug effects , Cells, Cultured , Culture Media/pharmacology , Dizocilpine Maleate/pharmacology , Extracellular Space/physiology , Rats , Rats, Sprague-Dawley , Theophylline/analogs & derivatives , Theophylline/pharmacology
20.
Brain Res ; 669(2): 320-4, 1995 Jan 16.
Article in English | MEDLINE | ID: mdl-7712189

ABSTRACT

In dissociated rat hippocampal neurons, slow bath application (1 ml/min) of glutamate (50 microM) increased both excitatory and inhibitory synaptic activities. This glutamate effect was abolished by tetrodotoxin or cadmium. The constant perfusion (1 h) of glutamate 50 microM was toxic to the neurons. This toxicity was also blocked by TTX. This suggests that unlike the excitotoxicity at a high (mM) concentration, the glutamate toxicity at 50 microM is mediated by its effect on synaptic transmission.


Subject(s)
Glutamic Acid/pharmacology , Hippocampus/physiology , Neurons/physiology , Synaptic Transmission/physiology , 6-Cyano-7-nitroquinoxaline-2,3-dione/pharmacology , Animals , Membrane Potentials , Rats , Tetrodotoxin/pharmacology
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