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1.
J Diabetes Complications ; 32(2): 196-202, 2018 02.
Article in English | MEDLINE | ID: mdl-29157869

ABSTRACT

AIMS: Self-compassion (SC), or treating oneself with kindness when dealing with personal challenges, has not been rigorously examined in people with T1D. SC has been shown to buffer against negative emotions and to be linked to improved health outcomes, but diabetes-specific SC has not been studied. This study aimed to adapt the Self-Compassion Scale and validate it for a diabetes-specific population. METHODS: We developed and validated a diabetes-specific version of the Self-Compassion Scale (Neff, 2003) in a sample of adults with T1D (N=542; 65% female; 97% non-Hispanic White; M age 41, SD=15.7; M A1c=7.3, SD=1; 72% insulin pump users; 50% continuous glucose monitoring [CGM] users). Confirmatory factor analyses (CFA), and reliability and construct validity analyses were conducted. Validity measures included diabetes distress, diabetes empowerment, diabetes numeracy, and A1c. RESULTS: A two-factor bi-factor structure showed best fit, providing support for use of the adapted scale (SCS-D) as a unitary construct. The 19-item unidimensional SCS-D demonstrated excellent internal consistency (ɑ=0.94; range of item-total correlations: 0.52-0.71) and construct validity. As hypothesized, higher SCS-D was associated with less distress, greater empowerment, and lower A1c, and was not associated with numeracy. CONCLUSIONS: The SCS-D is a reliable and valid measure of diabetes-specific self-compassion in adults with T1D.


Subject(s)
Diabetes Mellitus/psychology , Empathy , Psychometrics , Self Concept , Surveys and Questionnaires , Adult , Blood Glucose/metabolism , Blood Glucose Self-Monitoring/psychology , Blood Glucose Self-Monitoring/standards , Calibration , Cost of Illness , Diabetes Mellitus/therapy , Female , Humans , Insulin Infusion Systems/psychology , Insulin Infusion Systems/standards , Male , Middle Aged , Patient Participation/psychology , Psychometrics/methods , Psychometrics/standards , Reproducibility of Results , Self Efficacy , Stress, Psychological/diagnosis , Stress, Psychological/psychology , Surveys and Questionnaires/standards
2.
Public Health Action ; 8(4): 225-231, 2018 Dec 21.
Article in English | MEDLINE | ID: mdl-30775284

ABSTRACT

Objective: To move closer to achieving the third target of the UNAIDS 90-90-90 goals, we prospectively implemented a viral load (VL) champion (VLC) program aimed at enhancing VL monitoring and recognition of treatment failure. Design: Three clinics in eThekwini, Kwa-Zulu Natal (low-, medium- and high-volume, encompassing 9184 patients overall) were each assigned a VLC. We employed a descriptive analysis (chart audit) to compare the pre-intervention period to a 1-year post-intervention period. The number of patients with a VL test performed 6 and 12 months after the intervention was calculated as a proportion of VL tests due at those time points (VL completion rate). Results: The pre-implementation VL completion rate at the three sites was respectively 68% (140/205 patients), 54% (84/155 patients) and 64% (323/504 patients), and the 6-month post-implementation completion rate increased to 83% (995/1194 patients), 90% (793/878 patients) and 99% (3101/3124 patients) (P < 0.0001 for each site). VL completion rates remained significantly higher at 12 months post-implementation, with an average cumulative VL completion rate of >90% across all facilities. Conclusion: We demonstrate a successful, multifaceted, quality-improvement intervention centered on a clinic-level VLC which, taken to scale, has important implications for attaining the third UNAIDS 90-90-90 target.


Objectif : Dans le but de se rapprocher de l'atteinte de la troisième cible des objectifs 90-90-90 du Programme commun des Nations Unies sur le VIH/Sida (ONUSIDA), nous avons prospectivement mis en œuvre un programme « champion de la charge virale ¼ (VLC) visant à améliorer le suivi de la charge virale (VL) et la reconnaissance de l'échec du traitement.Schéma : Trois centres à eThekwini, Kwa-Zulu Natal (volume faible, moyen et élevé, soit 9184 patients au total), ont été chacun affectés au VLC. Nous employons une analyse descriptive (audit de dossiers) afin de comparer la période avant l'intervention à la période d'un an qui a suivi l'intervention. Le nombre de patients ayant eu un test VL 6 et 12 mois après l'intervention a été calculé comme une proportion de test VL exigibles à ces dates respectivement (taux d'achèvement du VL).Résultats : Le taux d'achèvement du VL avant la mise en route dans trois sites a été de 68% (140/205 patients), 54% (84/155 patients) et 64% (323/504 patients), respectivement, et le taux d'achèvement à 6 mois après la mise en œuvre a augmenté à 83% (995/1194 patients), 90% (793/878 patients) et 99% (3101/3124 patients), respectivement (P < 0,0001 pour chaque site). Les taux d'achèvement du VL sont restés significativement plus élevés à 12 mois après la mise en œuvre, avec un taux cumulé moyen du VL >90% dans toutes les structures.Conclusion : Nous avons montré la qualité d'une intervention d'amélioration réussie à multiples facettes, centrée sur le VLC au niveau des centres qui­à plus grande échelle­a des implications majeures pour l'atteinte de la troisième cible 90-90-90 de l'ONUSIDA.


Objetivo: Con el propósito de avanzar hacia el cumplimiento del tercer elemento del objetivo «90-90-90¼ del Programa Conjunto de las Naciones Unidas sobre el VIH/SIDA (ONUSIDA), se introdujo un programa con un promotor del seguimiento de la viremia, encaminado a reforzar la vigilancia de la concentración vírica y el reconocimiento del fracaso terapéutico.Método: En cada uno de tres consultorios de eThekwini, en Kwa-Zulu Natal (con una carga asistencial baja, intermedia y alta, que cubrían un total de 9184 pacientes) se nombró un promotor del seguimiento de la viremia. Mediante un análisis descriptivo, se comparó el período preintervención con un período posintervención de un año. El número de pacientes en quienes se practicó la viremia a los 6 y 12 meses después de la intervención se calculó como la proporción de las viremias previstas en estos puntos temporales (tasa de compleción de la viremia).Resultados: La tasa de compleción de la viremia en los tres centros fue como sigue: 68% (140/205 pacientes), 54% (84/155 pacientes) y 64% (323/504 pacientes) y a los 6 meses posintervención, esta tasa aumentó respectivamente a 83% (995/1194 pacientes), 90% (793/878 pacientes) y 99% (3101/3124 pacientes) (P < 0,0001 para cada centro). Las tasas de compleción de la viremia permanecieron significativamente más altas a los 12 meses posintervención con una tasa acumulada superior al 90% en todos los establecimientos.Conclusión: Se puso en evidencia una intervención polifacética eficaz de mejoramiento de la calidad centrada en un promotor clínico del seguimiento de la viremia en cada consultorio, cuya aplicación en una escala más amplia, tendría importantes repercusiones en favor del cumplimiento del tercer elemento del objetivo «90-90-90¼ del ONUSIDA.

3.
J Neuroimmunol ; 251(1-2): 25-32, 2012 Oct 15.
Article in English | MEDLINE | ID: mdl-22769060

ABSTRACT

Current immunotherapy of myasthenia gravis (MG) is often effective, but entails risks of infection and neoplasia. The "Guided Missile" strategy described here is designed to target and eliminate the individual's unique AChR-specific T cell repertoire, without otherwise interfering with the immune system. We genetically engineered dendritic cells to present AChR epitopes and simultaneously express Fas ligand in an ongoing EAMG model. In both in vitro and in vivo experiments, these engineered cells specifically killed AChR-responsive T cells without otherwise damaging the immune system. AChR antibodies were markedly reduced in the treated mice. Translation of this method to treat human MG is possible.


Subject(s)
Dendritic Cells/immunology , Dendritic Cells/transplantation , Immunotherapy/methods , Myasthenia Gravis, Autoimmune, Experimental/therapy , Animals , Antibodies/blood , Cells, Cultured , Disease Models, Animal , Epitopes/genetics , Epitopes/immunology , Fas Ligand Protein/genetics , Fas Ligand Protein/immunology , Female , Genetic Engineering , Mice , Mice, Inbred C57BL , Myasthenia Gravis, Autoimmune, Experimental/blood , Myasthenia Gravis, Autoimmune, Experimental/immunology , Receptors, Cholinergic/genetics , Receptors, Cholinergic/immunology , T-Lymphocytes/immunology
4.
Ann N Y Acad Sci ; 998: 520-32, 2003 Sep.
Article in English | MEDLINE | ID: mdl-14592923

ABSTRACT

Although treatment of MG with general immunosuppressive agents is often effective, it has important drawbacks, including suppression of the immune system as a whole, with the risks of infection and neoplasia, and numerous other adverse side effects. Ideally, treatment of MG should eliminate the specific pathogenic autoimmune response to AChR, without otherwise suppressing the immune system or producing other adverse side effects. Although antibodies to AChR are directly responsible for the loss of AChRs at neuromuscular junctions in MG, the AChR antibody response is T cell-dependent, and immunotherapy directed at T cells can abrogate the autoantibody response, with resulting benefit. As in other autoimmune diseases, the T cell response in MG is highly heterogeneous. The design of specific immunotherapy must take this heterogeneity into account and target the entire repertoire of AChR-specific T cells. We describe our investigation of a novel strategy for specific immunotherapy of MG, involving gene transfer to convert antigen-presenting cells (APCs) to "guided missiles" that target AChR-specific T cells, and that induce apoptosis and elimination of those T cells. This strategy uses the ability of APCs from a given individual to present the entire spectrum of AChR epitopes unique for that individual, and thereby to target the entire repertoire of antigen-specific T cells of the same individual. Using viral vectors, we have genetically engineered the APCs to process and present the most important domain of the AChR molecule, and to express a "warhead" of Fas ligand (FasL) to eliminate the activated AChR-specific T cells with which they interact. Our results show that the APCs express the appropriate gene products, and effectively and specifically eliminate AChR-specific T cells by the Fas/FasL pathway, while sparing T cells of other specificities.


Subject(s)
Antigen-Presenting Cells/immunology , Genetic Engineering/methods , Immunotherapy , Myasthenia Gravis, Autoimmune, Experimental/therapy , T-Lymphocytes/immunology , Animals , Cell Death , Cell Line , Dendritic Cells , Humans , Lymph Nodes/immunology , Mice , Mice, Inbred C57BL , Mice, Knockout , Myasthenia Gravis, Autoimmune, Experimental/chemically induced , Myasthenia Gravis, Autoimmune, Experimental/veterinary , Proteins/metabolism , Rats , Rats, Inbred Lew , Receptors, Cholinergic/chemistry , Receptors, Cholinergic/immunology , Receptors, Cholinergic/metabolism , Signal Transduction , Spleen/cytology , Spleen/immunology , T-Lymphocytes/metabolism , Time Factors , fas Receptor/metabolism
5.
Cell Immunol ; 208(2): 137-47, 2001 Mar 15.
Article in English | MEDLINE | ID: mdl-11333146

ABSTRACT

We describe a strategy for specific immunotherapy of myasthenia gravis (MG) based on genetic engineering of antigen presenting cells (APCs) to present the autoantigen acetylcholine receptor (AChR) and express the "warhead" Fas ligand (FasL). For transduction of APCs we prepared recombinant attenuated vaccinia virus vectors carrying the following three gene constructs: (i) AChR fused to LAMP1 to present AChR and target AChR-specific T cells; (ii) FasL to eliminate the targeted T cells; and (iii) truncated FADD to protect APCs from self-destruction by FasL. The engineered APCs effectively expressed the genes of interest and killed AChR-specific T cells in culture by the Fas/FasL pathway. T cells specific for an unrelated antigen were spared. Our in vitro demonstration that engineered APCs target and kill antigen-specific T cells represents a promising novel strategy for specific immunotherapy of MG and other autoimmune diseases.


Subject(s)
Adaptor Proteins, Signal Transducing , Autoantigens/immunology , Carrier Proteins/immunology , Membrane Glycoproteins/immunology , Myasthenia Gravis, Autoimmune, Experimental/immunology , Receptors, Cholinergic/immunology , T-Lymphocytes/immunology , fas Receptor/immunology , Animals , Antigen-Presenting Cells/immunology , Antigens, CD/genetics , Antigens, CD/immunology , Autoantigens/genetics , Carrier Proteins/genetics , Cell Line , Fas Ligand Protein , Fas-Associated Death Domain Protein , Female , Gene Expression , Genetic Vectors , Immunotherapy , Lysosomal-Associated Membrane Protein 1 , Lysosomal Membrane Proteins , Membrane Glycoproteins/genetics , Mice , Mice, Inbred C57BL , Mice, Inbred MRL lpr , Myasthenia Gravis, Autoimmune, Experimental/therapy , Rats , Rats, Inbred Lew , Receptors, Cholinergic/genetics , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/immunology , Tumor Cells, Cultured , Vaccinia virus
6.
J Immunol ; 166(7): 4773-9, 2001 Apr 01.
Article in English | MEDLINE | ID: mdl-11254740

ABSTRACT

We tested the hypothesis that APCs genetically engineered to present an Ag and to express Fas ligand (FasL) simultaneously can target and eliminate Ag-specific T cells. Transgenic T cells specific for influenza hemagglutinin (HA) were used as targets. We prepared recombinant vaccinia virus vectors (VVV) to transfer the gene constructs individually or simultaneously into APCs. We prevented unwanted viral replication by attenuating the VVVs with psoralen-UV light treatment. For presentation of the HA Ag, APCs were transduced with cDNA for HA flanked by sequences of the lysosome-associated membrane protein that direct efficient processing and presentation of the Ag by APCs. As a "warhead" for the APCs, we transduced them with the gene for FasL, which induces apoptosis of Fas-expressing activated T cells. To protect the transduced APCs from self-destruction by FasL, we transferred cDNA for a truncated form of Fas-associated death domain, which inhibits Fas-mediated cell death. Our results show that the engineered APCs effectively expressed the genes of interest. APCs transduced with VVV carrying all three gene constructs specifically killed HA-transgenic T cells in culture. Coculture with T cells specific for an unrelated Ag (OVA) had no significant effect. Our in vitro findings show that APCs can be genetically engineered to target and kill Ag-specific T cells and represent a promising novel strategy for the specific treatment of autoimmune diseases.


Subject(s)
Adaptor Proteins, Signal Transducing , Adoptive Transfer/methods , Antigen-Presenting Cells/transplantation , Protein Engineering/methods , Adjuvants, Immunologic/genetics , Animals , Apoptosis/genetics , Apoptosis/immunology , Carrier Proteins/genetics , Cell Line , Cytotoxicity, Immunologic/genetics , Fas Ligand Protein , Fas-Associated Death Domain Protein , Gene Targeting/methods , Gene Transfer Techniques , Genetic Vectors/chemical synthesis , Genetic Vectors/immunology , Hemagglutinin Glycoproteins, Influenza Virus/immunology , Humans , Interphase/genetics , Interphase/immunology , Ligands , Membrane Glycoproteins/genetics , Membrane Glycoproteins/immunology , Membrane Glycoproteins/metabolism , Membrane Glycoproteins/toxicity , Mice , Mice, Inbred BALB C , Mice, Transgenic , Recombination, Genetic/immunology , T-Lymphocytes/immunology , T-Lymphocytes/pathology , Vaccinia virus/genetics , Vaccinia virus/immunology , fas Receptor/genetics , fas Receptor/immunology
7.
Brain Res ; 763(1): 69-78, 1997 Jul 18.
Article in English | MEDLINE | ID: mdl-9272830

ABSTRACT

Detailed quantitative information on catecholamines and 5-hydroxytryptamine (serotonin) in the human thalamus is much needed because of increasing interest in norepinephrine and serotonin as modulators of thalamic behavioral state control and overall information processing. This study provides three-dimensional distribution patterns of these monoamines in postmortem thalami from 13 normal subjects (no known neurological or psychiatric histories). The patterns come from a relatively fine-grained grid mapping procedure on successive coronal sections. Samples were analyzed by high performance liquid chromatography with electrochemical detection. The highest endogenous concentrations of norepinephrine are found in a ventromedial core that includes a number of the medial and intralaminar sub-nuclei but extends only slightly into the sensory regions of the lateral tier. The posterior portion of the thalamus, the pulvinar, contains low levels of norepinephrine. The distribution of 5-hydroxytryptamine is quite similar to that of norepinephrine in the rostral two-thirds of thalamus; however, in the pulvinar region, levels of serotonin are considerably increased and differ markedly between individual thalami. The study provides the first definitive mapping of serotonin levels in human thalamus. Consistent with many animal studies, there is no evidence for major dopaminergic innervation of human thalamus. By emphasizing the pattern distribution of the monoamines rather than the absolute values, it can be shown that the ambiguities of postmortem degradation frequently associated with biochemical assays are largely avoided. The terminal field distribution of norepinephrine is an essentially constant neurochemical signature in all thalami examined. The utility of the biochemical grid mapping procedure may be especially significant in terms of matching with data from functional neuroimaging techniques.


Subject(s)
Norepinephrine/metabolism , Serotonin/metabolism , Thalamus/metabolism , Brain/physiology , Brain Mapping , Humans , Image Processing, Computer-Assisted
8.
Ann N Y Acad Sci ; 778: 258-72, 1996 Feb 13.
Article in English | MEDLINE | ID: mdl-8610979

ABSTRACT

Because of the antibody-mediated pathogenesis of MG, it is of particular interest to understand the effects of oral administration of the autoantigen AChR on the disease process. It is now clear that feeding AChR prior to immunization can prevent clinical manifestation of EAMG. It initially primed, then inhibited, antibody responses to foreign (Torpedo) AChR and self (rat) AChR, with a delayed onset. Cellular responses to AChR, evaluated by lymphocyte proliferation and IL-2 production, were markedly inhibited. The effects were dependent on the dose and purity of the fed antigen. Tolerance to an orally administered unrelated antigen, OVA, was more prompt in development and more profound, illustrating the influence of the nature of the antigen on tolerance. The tolerance induced was antigen specific. Oral administration of AChR after immunization resulted in inhibition of the clinical manifestation of EAMG, concomitant with a paradoxical enhancement of the AChR-antibody responses. Both the clinical benefit and the antibody response appear to be dependent on the feeding protocol. These findings suggest that a molecule with less immunogenic potential than native AChR may be required for safe and effective oral treatment of ongoing disease.


Subject(s)
Autoantigens/immunology , Encephalomyelitis, Autoimmune, Experimental/immunology , Immune Tolerance , Myasthenia Gravis/immunology , Myasthenia Gravis/therapy , Administration, Oral , Animals , Antibody Formation , Autoantigens/administration & dosage , Encephalomyelitis, Autoimmune, Experimental/therapy , Humans , Immunotherapy , Ovalbumin/administration & dosage , Ovalbumin/immunology , Rabbits , Rats , Rats, Inbred Lew , Receptors, Cholinergic/immunology , T-Lymphocytes/immunology , T-Lymphocytes, Regulatory/immunology
9.
Brain Res Mol Brain Res ; 26(1-2): 55-60, 1994 Oct.
Article in English | MEDLINE | ID: mdl-7854066

ABSTRACT

Many properties of skeletal muscle are closely regulated by motor nerves. We have shown that nerve stimulation in vivo induced a rapid rise in mRNA for the immediate early gene (IEG) zif268 in stimulated muscle. However, the mechanisms leading to neural regulation of zif268 gene expression in muscle are not yet known. In this study, we used a mammalian skeletal muscle cell line (C2C12) to analyze the role of cholinergic transmission, and calcium flux, in the neural regulation of zif268. Treatment of the C2C12 muscle cells with carbachol, a cholinergic agonist, induced zif268 gene expression rapidly and transiently. This effect was blocked by alpha-bungarotoxin (alpha-BuTx), which specifically blocks nicotinic acetylcholine receptors. Treatment with ryanodine or dantrolene, which block the calcium release channel of the sarcoplasmic reticulum, inhibited the carbachol-induced zif268 response essentially completely. Calcium influx produced by A23187, a calcium ionophore, induced an increase of zif268 gene expression equivalent to the effect of carbachol stimulation. These results suggest that the effect of neural stimulation on zif268 may be attributable to cholinergic transmission, and the subsequent release of calcium from the sarcoplasmic reticulum.


Subject(s)
Calcium/metabolism , Carbachol/pharmacology , DNA-Binding Proteins/biosynthesis , Gene Expression , Genes, Immediate-Early , Muscle, Skeletal/physiology , Transcription Factors/biosynthesis , Animals , Blotting, Northern , Bungarotoxins/pharmacology , Calcimycin/pharmacology , Cell Line , Dantrolene/pharmacology , Gene Expression/drug effects , Mammals , Motor Neurons/physiology , Muscle, Skeletal/drug effects , Muscle, Skeletal/innervation , RNA, Messenger/analysis , RNA, Messenger/biosynthesis , Ryanodine/pharmacology , Zinc Fingers
10.
J Neurochem ; 63(3): 917-26, 1994 Sep.
Article in English | MEDLINE | ID: mdl-8051568

ABSTRACT

Electrical stimulation of the ascending dorsal tegmental bundle of the locus ceruleus was used to elicit controlled release of norepinephrine. Real-time in vivo monitoring in the brains of urethane-anesthetized rats was observed with high speed chronocoulometry at rapidly responding carbon fiber electrodes. Using modeling similar to that developed for dopamine release, the electrochemical signals were characterized as the balance between norepinephrine release per electrical stimulation pulse and apparent Michaelis-Menten reuptake parameters. Stimulation produced simultaneous overflow release at all terminal fields examined. The release and reuptake characteristics varied considerably in different regions. If the parameters are normalized to endogenous concentration in the terminal fields, release but not reuptake correlates with innervation density in several regions. Stimulated release results in norepinephrine overflow and transport in most brain regions with half-lives of 1-3 s and overflow distances of 25-50 microns at most. A surprising exception occurs in the upper layers of cortex (cingulate and sensory) where half-lives may be in the 10s of seconds and spatial reach may be up to 100 microns. The uptake in the outer cortical layers appears to be minimal and comparable with only nonspecific reuptake.


Subject(s)
Brain/physiology , Norepinephrine/metabolism , Animals , Electric Stimulation , Electrochemistry , Kinetics , Locus Coeruleus/physiology , Models, Biological , Rats
12.
Brain Res ; 604(1-2): 349-53, 1993 Feb 26.
Article in English | MEDLINE | ID: mdl-8457864

ABSTRACT

IN vivo electrochemistry was used to monitor the effects of several voltage-sensitive calcium channel (VSCC) antagonists (e.g. divalent metal ions, diltiazem and omega-conotoxin GVIA (omega-CT) on the electrically evoked release of dopamine (DA) in the striatum and norepinephrine (NE) in the thalamus of the anesthetized rat. The results suggest that the N-type voltage-sensitive calcium channel is the primary VSCC involved in the electrically stimulated release of DA in the striatum, whereas stimulated release of NE in the thalamus was only partially dependent on N-type VSCC. In addition, DA release appears to be more sensitive to VSCC antagonism than does NE release with the in vivo application used in this study.


Subject(s)
Calcium Channel Blockers/pharmacology , Diltiazem/pharmacology , Dopamine/metabolism , Manganese/pharmacology , Norepinephrine/metabolism , Peptides, Cyclic/pharmacology , Thalamus/physiology , Animals , Cations, Divalent , Electric Stimulation , Male , Rats , Rats, Sprague-Dawley , Thalamus/drug effects , omega-Conotoxin GVIA
13.
J Neurochem ; 60(2): 442-8, 1993 Feb.
Article in English | MEDLINE | ID: mdl-8419530

ABSTRACT

Electrical stimulation of an ascending path of the locus ceruleus-norepinephrine system was used to elicit release of norepinephrine at noradrenergic terminal fields of the rat thalamus. Overflow into the extracellular fluid space was measured by fast in vivo chronoamperometry. At pretreated carbon fibers, the electrochemical signal consists of a sharp peak of approximately 20-30 s duration followed by a slower, plateau-like decay to baseline. The peak, characterized by a variety of pharmacological manipulations and dialysis perfusion, is primarily due to norepinephrine. The plateau was shown to correspond to metabolite efflux of 3,4-dihydroxy-phenylacetic acid. By varying the degree of electrochemical pretreatment, the response time and sensitivity of the fibers can be tuned to follow the entire signal or to select the separate components for detailed evaluation. This approach can be used to provide new information on the spatial and temporal characteristics of stimulated neurotransmitter release.


Subject(s)
Locus Coeruleus/physiology , Norepinephrine/metabolism , Signal Transduction , Thalamus/physiology , 3,4-Dihydroxyphenylacetic Acid/metabolism , Animals , Ascorbic Acid/metabolism , Chromatography, High Pressure Liquid , Dopamine/metabolism , Electric Stimulation , Kinetics , Male , Methoxyhydroxyphenylglycol/analogs & derivatives , Methoxyhydroxyphenylglycol/metabolism , Rats , Rats, Sprague-Dawley , Time Factors
14.
J Neurochem ; 60(2): 449-53, 1993 Feb.
Article in English | MEDLINE | ID: mdl-8419531

ABSTRACT

As in the preceding study, electrical stimulation was used to effect release overflow of norepinephrine in the rat thalamus. Using a weak electrochemical pretreatment of a carbon fiber electrode, it was possible to "tune in" the electrochemical response signal for norepinephrine without metabolite interference. This reasonably selective signal was then used to study the degradation of norepinephrine release ability caused by prolonged stimulation. Further, the signals were modeled by the method used successfully for stimulated dopamine overflow, providing hitherto unavailable information on the temporal and spatial characteristics of norepinephrine release overflow. Pertinent comparisons between the release characteristics of the dopamine and norepinephrine systems show that the half-life for norepinephrine in the extracellular fluid space is approximately 1 s in thalamus compared with 33 ms for dopamine in caudate.


Subject(s)
Norepinephrine/metabolism , Thalamus/physiology , Animals , Biological Transport , Desipramine/pharmacology , Dopamine/metabolism , Electric Stimulation , Kinetics , Male , Pargyline/pharmacology , Rats , Rats, Sprague-Dawley , Reference Values , Thalamus/drug effects , Time Factors
15.
Psychiatry Res ; 45(4): 203-8, 1992 Dec.
Article in English | MEDLINE | ID: mdl-1363335

ABSTRACT

Previous studies have indicated a marked increase in the dopamine/norepinephrine ratio in thalami of schizophrenic patients compared with those of control subjects. Since these results all came from patients who were receiving neuroleptic drugs, the possibility exists that the increased dopamine concentrations are an effect of medication. To address this question, similar analyses were done on thalami from Huntington's Disease patients who had received neuroleptic treatment. The results showed no differences between the thalami of Huntington's Disease patients and controls, strongly suggesting that chronic treatment with neuroleptic drugs does not result in an increase of endogenous dopamine in the thalami of human subjects.


Subject(s)
Antipsychotic Agents/therapeutic use , Dopamine/metabolism , Schizophrenia/drug therapy , Schizophrenic Psychology , Thalamic Nuclei/drug effects , Adult , Aged , Chlorpromazine/therapeutic use , Haloperidol/therapeutic use , Humans , Huntington Disease/drug therapy , Huntington Disease/pathology , Middle Aged , Norepinephrine/metabolism , Schizophrenia/pathology , Thalamic Nuclei/pathology
16.
Brain Res Bull ; 29(6): 891-6, 1992 Dec.
Article in English | MEDLINE | ID: mdl-1473020

ABSTRACT

The purpose of this study was to determine whether elevated levels of 3,4-dihydroxyphenylacetic acid (DOPAC), the major metabolite of dopamine (DA) in the brain, could decrease the DA content in the striatum. Levels of DA were determined by high pressure liquid chromatography with electrochemical detection (HPLC-EC) in the striatum of male rats 24 h following a single intracerebral administration of DOPAC into the right striatum. DOPAC at 16.8 micrograms reduced the DA content of the infused side by 17%, p = 0.01. In contrast, infusion of 1.68 micrograms of DOPAC or the vehicle had no effect on striatal DA levels. Coapplication of the antioxidant, ascorbic acid, at 0.2 mg/ml with 16.8 micrograms of DOPAC prevented the decrease in DA content. Furthermore, infusion of 18.2 micrograms of homovanillic acid (HVA), the product of DOPAC methylation, had no effect on striatal DA. These results indicate that DOPAC may undergo autoxidation in vivo to produce neurotoxic species which may result in reduction of striatal DA. Formation of such an autoxidation product(s) of endogenous DOPAC was verified in the extracellular fluid of striatal slices in vitro.


Subject(s)
3,4-Dihydroxyphenylacetic Acid/pharmacology , Brain/physiology , Caudate Nucleus/physiology , Corpus Striatum/metabolism , Dopamine/metabolism , 3,4-Dihydroxyphenylacetic Acid/administration & dosage , Animals , Caudate Nucleus/drug effects , Chromatography, High Pressure Liquid , Corpus Striatum/drug effects , Homovanillic Acid/pharmacology , In Vitro Techniques , Infusions, Parenteral , Male , Membrane Potentials/drug effects , Rats , Rats, Sprague-Dawley
17.
Brain Res ; 577(1): 49-56, 1992 Apr 10.
Article in English | MEDLINE | ID: mdl-1355696

ABSTRACT

The ventrobasal complex (VB) of the thalamus was monitored in awake rats for the presence of norepinephrine (NE) overflow following pharmacological manipulations and physiological stimulation. Overflow was detected using chronoamperometry with electrochemically pretreated, Nafion-coated carbon fiber microelectrodes. In vivo evaluation of the electrode responses to systemic drug administration showed that alpha-methyl-p-tyrosine (alpha-MPT) and FLA-63 caused decreases in baseline current. Increases in baseline current in the VB were observed in animals treated with pargyline, yohimbine and yohimbine injected 2 h postpargyline. The results suggest that an electrochemical signal primarily due to NE overflow can be monitored in thalamic regions. Vigorous somatosensory stimulation induced small, long-lasting (approximately 30 min), reproducible electrochemical signals in the VB which were suppressed by alpha-MPT or FLA-63. These studies provide in vivo evidence which suggests that stressful somatosensory input to the VB initiates the release of NE.


Subject(s)
Norepinephrine/metabolism , Stress, Psychological/metabolism , Thalamus/metabolism , Animals , Bis(4-Methyl-1-Homopiperazinylthiocarbonyl)disulfide/pharmacology , Calibration , Electrochemistry , Male , Methyltyrosines/pharmacology , Microelectrodes , Movement/physiology , Rats , Rats, Inbred Strains , Tyrosine 3-Monooxygenase/antagonists & inhibitors , alpha-Methyltyrosine
18.
Neurochem Res ; 17(1): 23-7, 1992 Jan.
Article in English | MEDLINE | ID: mdl-1347161

ABSTRACT

In vivo electrochemistry has been a valuable tool in detecting real time neurochemical changes in extracellular fluid. Absolute selectivity has been difficult to achieve previously, but we report here a carbon fiber electrode and measurement technique which is specific for one oxidizable species: ascorbic acid. Ascorbic acid is highly concentrated in extra- as well as intracellular brain spaces, and appears to undergo dynamic changes in response to a variety of physiological and pathophysiological circumstances. Recent studies have implicated glutamatergic mechanisms which give rise to extracellular changes in brain ascorbate, and we confirm and extend these observations. Preliminary studies, directed towards examining ascorbic acid as an index and/or result of hypoxia, spreading depression, and seizure activity, have been undertaken and the results are reported herein.


Subject(s)
Ascorbic Acid/metabolism , Brain/metabolism , Cortical Spreading Depression/physiology , Hypoxia/metabolism , Seizures/metabolism , Animals , Ascorbate Oxidase/metabolism , Brain/drug effects , Electric Stimulation , Electrochemistry , Glutamates/metabolism , Glutamates/pharmacology , Glutamic Acid , Male , Potassium/metabolism , Rats , Rats, Inbred Strains
19.
Brain Res ; 565(1): 17-22, 1991 Nov 22.
Article in English | MEDLINE | ID: mdl-1685348

ABSTRACT

A recently described in vivo voltammetric electrode selectively records rapid changes in extracellular fluid (ECF) levels of ascorbic acid. Using this detector, the nature of glutamate-induced efflux of ascorbate into ECF was investigated using pharmacological tools. Ascorbate signals were shown to be directly related to amounts of microinjected glutamate. Blockers of glutamate reuptake, homocysteic acid and D,L-threo-beta-hydroxy-aspartic acid, virtually eliminate the ascorbate signal. A more specific reuptake blocker (the stilbene isothiocyano derivative (SITS) does not completely inhibit ascorbate efflux, suggesting that the glutamate uptake which is coupled to ascorbic acid exchange is both neuronal and glial in nature. Other pharmacological experiments indicate that excitatory amino acid receptors are not involved in the glutamate-elicited ascorbate efflux; it is primarily a function of the glutamate/ascorbate heteroexchange process as described earlier. The possible role(s) of brain ascorbate in the general functioning of the pervasive glutamate neurotransmitter systems are discussed.


Subject(s)
Ascorbic Acid/metabolism , Brain/physiology , Glutamates/pharmacology , 4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid/administration & dosage , 4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid/pharmacology , Animals , Aspartic Acid/administration & dosage , Aspartic Acid/analogs & derivatives , Aspartic Acid/pharmacology , Brain/drug effects , Brain/metabolism , Corpus Striatum/physiology , Electric Stimulation , Electrochemistry/methods , Globus Pallidus/physiology , Glutamates/administration & dosage , Glutamic Acid , Hippocampus/physiology , Kynurenic Acid/pharmacology , Male , Microinjections , N-Methylaspartate/administration & dosage , N-Methylaspartate/pharmacology , Organ Specificity , Potentiometry , Rats , Rats, Inbred Strains , Stereotaxic Techniques , Thalamus/physiology
20.
Eur J Pharmacol ; 201(1): 111-3, 1991 Aug 16.
Article in English | MEDLINE | ID: mdl-1838982

ABSTRACT

Antioxidants such as ascorbic acid (AA) and dithiothreitol (DTT), can prevent 3,4-dihydroxyphenylacetic acid (DOPAC) inhibition of [3H]spiperone binding to neuronal dopamine D2 receptors. The DOPAC quinone produced from auto-oxidation is believed to be responsible for the irreversible inhibition noted. Quinone conjugation to proteins occurs readily in vivo, and thus, auto-oxidation of DOPAC and other endogenous catechol containing compounds could be an important component of protein modification during on-going neuronal physiology.


Subject(s)
3,4-Dihydroxyphenylacetic Acid/pharmacology , Ascorbic Acid/pharmacology , Dithiothreitol/pharmacology , Neurons/drug effects , Receptors, Dopamine/metabolism , Spiperone/metabolism , 3,4-Dihydroxyphenylacetic Acid/metabolism , Binding Sites , Corpus Striatum/drug effects , Corpus Striatum/metabolism , In Vitro Techniques , Neurons/metabolism , Oxidation-Reduction , Receptors, Dopamine D2
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