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1.
Preprint in English | medRxiv | ID: ppmedrxiv-21258190

ABSTRACT

BackgroundConvalescent plasma (CP) quickly emerged as one of the first investigational treatment options for COVID-19. Evidence supporting CP for treating patients hospitalized with COVID-19 has been inconclusive, leading to conflicting recommendations regarding its use. The primary objective was to perform a comparative effectiveness study of CP for all-cause, in-hospital mortality in patients with COVID-19. MethodsThe matched, multicenter, electronic health records-based, retrospective cohort study included 44,770 patients hospitalized with COVID-19 in one of 176 HCA Healthcare-affiliated community hospitals across the United States from March 2 to October 7, 2020. Coarsened exact matching (1:k) was employed resulting in a sample of 3,774 CP and 10,687 comparison patients. ResultsExamining mortality using a shared frailty model and controlling for concomitant medications, calendar date of admission, and days from admission to transfusion demonstrated a significant association of CP with lower risk of mortality compared to the comparison group (aHR = 0.71, 95% CI 0.59-0.86, p<0.001). Examination of patient risk trajectories, represented by 400 clinico-demographic features from our Real-Time Risk Model (RTRM), indicated that patients who received CP recovered more quickly. The time from admission to CP transfusion was significantly associated with risk of mortality and stratification revealed that CP within 3 days after admission, but not 4-7 days, was associated with a significant reduction in mortality risk (aHR = 0.53, 95% CI 0.47-0.60, p<0.001). CP serology level was inversely associated with mortality when controlling for interaction with days to transfusion (HR = 0.998, 95% CI 0.997-0.999, p = 0.013) but was not significant in a univariable analysis. ConclusionUtilizing this large, diverse, multicenter cohort, we demonstrate that CP is significantly associated with reduced risk of in-hospital mortality. These observations demonstrate the utility of real-world evidence and suggest the need for further evaluation prior to abandoning CP as a viable therapy for COVID-19. FundingThis research was supported, in whole, by HCA Healthcare and/or an HCA Healthcare affiliated entity including Sarah Cannon and Genospace. Research in Context Evidence before this studyDiscrepant reports of the efficacy of various treatments for COVID-19, including convalescent plasma (CP), emerged from a rapidly evolving political and interventional landscape of the pandemic. Furthermore, clinical interpretations of this discordant data led to underuse, overuse and misuse of certain interventions, often ignoring mechanistic context altogether. CP has been utilized in prior pandemics/epidemics to introduce antibodies to elicit an immune response during the viral phase of infection. Thus, CP received early priority for emergency use and randomized trial engagement. Initially, the United States had issued individual emergency investigational new drug (eIND) use for CP and initiated its expanded access protocol (EAP) to monitor its safety profile and to allow broader access. This effectively restricted access to those with severe disease, which is not mechanistically aligned with targeting the viral phase. Many randomized control trials (RCTs) were being setup for testing efficacy of CP in the inpatient setting and, to a lesser extent, the outpatient setting. Some trial designs focused on severe disease and others on less severe. United States RCTs had additional enrollment challenges due to competing patient access to EAP. All studies were limited by supply and demand due to regional outbreaks and to the shear operational effort of coordinating donations, sampling, serology testing, ordering, and distribution. To date, most matched studies and RCTs around the globe have shown a trend of CP providing survival benefit, but all had relatively small cohorts except the RECOVERY trial, which failed to show a benefit with CP. Results ranged from no significant effect to 56% reduction in mortality with the latter coming out of a multisite RCT based in New York and Rio De Janeiro. There has been a minimum of nine matched control studies and seven randomized control trials evaluating convalescent plasma. We frequently assessed World Health Organization (WHO), United Stated Food and Drug Administration (FDA), BARDA/Mayo Clinic led EAP, and the United States Center for Disease Control and Prevention (CDC) resources as well as queried both preprint archives (MedRXIV & SSRN) and PubMed with the search terms "retrospective", "convalescent plasma", "randomized", "trial", "comparative effect", "COVID", "hospital", "in-hospital", "hospitalized" and "mortality" to ensure we were considering the most recent methodology and results generated for CP. The last search was performed on May 14, 2021. No date restrictions or language filters were applied. Added value of this studyTo our knowledge, this study is the largest and most geographically diverse of its kind to comprehensively evaluate and confirm the beneficial association of CP with all-cause mortality in patients hospitalized with COVID-19. Our data provides context to optimal delivery and validates recent trends in the literature showing CP benefit. There is a dose-response effect with CP antibody levels and we demonstrate that sooner really is better in accordance with the mechanisms of viral clearance and immune regulation. Finally, this is all done in the context of a diverse community setting in one of the largest hospital systems in the United States. Implications of all the available evidenceAs novel, more virulent and transmissible SARS-CoV-2 variants emerge around the globe and as reports of post-vaccine "breakthrough" infections and vaccine hesitancy increase, there is a renewed motivation to identify effective treatments for hospitalized patients. The data presented here, along with a growing body of evidence from matched-control studies and RCTs, demonstrate that further evaluation is required prior to abandoning CP as an effective intervention in the treatment of hospitalized COVID-19 patients.

2.
Trans R Soc Trop Med Hyg ; 111(10): 457-463, 2017 10 01.
Article in English | MEDLINE | ID: mdl-29346640

ABSTRACT

Background: Preventive chemotherapy (PC), the large-scale administration of anthelminthics, is recommended by the World Health Organization (WHO) for the control of soil-transmitted helminthiasis (STH). Since 2010, donated anthelminthics for STH have boosted the implementation of PC programmes in children, achieving global coverage of more than 60% in 2015. The WHO Global Health Estimates attribute an annual loss of over 3.3 million disability-adjusted life-years (DALYs) to STH. The aim of this study is to estimate the impact of PC programmes on child morbidity. Method: We used data from the WHO Global Health Estimates, national coverage data on PC and the results of an evaluation of the impact of PC in 17 countries on morbidity previously conducted by our group. Results: We estimated that the implementation of PC averted in 2015 over 44% of the DALYs that would have been caused in children by STH without the control intervention. A reduction in morbidity of over 75% is expected, if the global target is reached in 2020. If the programme is subsequently maintained, morbidity from STH will be almost totally removed by 2025. Conclusions: In endemic areas, preventive chemotherapy provides a significant health benefit. We consider this estimation potentially useful to evaluate the cost utility of the investment made by several endemic countries on PC to control STH.


Subject(s)
Anthelmintics/administration & dosage , Chemoprevention , Disease Eradication/organization & administration , Global Health , Helminthiasis/drug therapy , Mass Drug Administration/statistics & numerical data , School Health Services/statistics & numerical data , Animals , Anthelmintics/economics , Chemoprevention/economics , Chemoprevention/methods , Child , Cost-Benefit Analysis , Disease Eradication/economics , Female , Helminthiasis/epidemiology , Helminthiasis/prevention & control , Humans , Male , Mass Drug Administration/economics , Prevalence , Program Evaluation , Quality-Adjusted Life Years , School Health Services/economics , Schools , Soil/parasitology , World Health Organization
3.
Neuroscience ; 140(3): 1051-65, 2006 Jul 07.
Article in English | MEDLINE | ID: mdl-16677768

ABSTRACT

Cyclooxygenase-2 is expressed at low levels in a subset of neurons in CNS and is rapidly induced by a multiplicity of factors including seizure activity. A putative relationship exists between cyclooxygenase-2 induction and glutamatergic neurotransmission. Cyclooxygenase-1 is constitutively expressed in glial cells and has been specifically linked to microglia. In this study we evaluated cyclooxygenase-2 protein immunocytochemically and found markedly enhanced immunostaining primarily in olfactory-limbic regions at 2, 6 and 24 h following kainate-induced status epilepticus. Impressive enhanced cyclooxygenase-2 immunoreactivity was localized in anterior olfactory nucleus, tenia tecta, nucleus of the lateral olfactory tract, piriform cortex, lateral and basolateral amygdala, orbital frontal cortex, nucleus accumbens (shell) and associated areas of ventral striatum, entorhinal cortex, dentate gyrus granule cells and hilar neurons, hippocampal CA subfields and subiculum. Alternate sections were processed for dual immunocytochemical analysis utilizing c-Fos and cyclooxygenase-2 antiserum to examine the possibility that the neuronal induction of cyclooxygenase-2 was associated with seizure activity. Neurons that showed a timeline of cyclooxygenase-2 upregulation were found to possess c-Fos immunopositive nuclei. Additional results from all seizure groups showed cyclooxygenase-1 induction in microglia, which was confirmed by Western blot analysis of hippocampus. Western blot and real-time quantitative RT-PCR analysis showed significant upregulation of cyclooxygenase-2 expression, confirming its induction in neurons. These data indicate that cyclooxygenase-2 induction in a neuronal network can be a useful marker for pathways associated with seizure activity.


Subject(s)
Cyclooxygenase 2/metabolism , Encephalitis/enzymology , Epilepsy/enzymology , Limbic System/enzymology , Olfactory Pathways/enzymology , Prosencephalon/enzymology , Animals , Biomarkers/metabolism , Convulsants/pharmacology , Disease Models, Animal , Encephalitis/etiology , Encephalitis/physiopathology , Epilepsy/chemically induced , Epilepsy/physiopathology , Gliosis/chemically induced , Gliosis/enzymology , Gliosis/physiopathology , Glutamic Acid/metabolism , Immunohistochemistry , Kainic Acid/pharmacology , Limbic System/drug effects , Limbic System/physiopathology , Male , Microglia/drug effects , Microglia/enzymology , Olfactory Pathways/drug effects , Olfactory Pathways/physiopathology , Prosencephalon/drug effects , Prosencephalon/physiopathology , Proto-Oncogene Proteins c-fos/metabolism , Rats , Rats, Sprague-Dawley , Synaptic Transmission/drug effects , Synaptic Transmission/physiology , Up-Regulation/drug effects , Up-Regulation/physiology
4.
Brain Res ; 1089(1): 171-8, 2006 May 17.
Article in English | MEDLINE | ID: mdl-16635480

ABSTRACT

The purpose of this study was to identify the CNS cellular constituent immunoreactive for specific P2X7 receptor antiserum in the kainate-induced seizure and non-seizure rat brain. Analysis of P2X7 immunocytochemistry (ICC) revealed small immunoreactive cells with processes showing distinct morphological changes as seizures progressed in time. These morphological changes were reminiscent of reactive glia during CNS injury. In order to determine the identity of this non-neuronal cellular constituent, we employed dual ICC techniques using sequential antibody incubations and reacted the sections with contrasting chromagens. Specific glial markers tested in the series included Iba1 (microglia), COX-1 (microglia), and GFAP (astroglia). Results of this study revealed distinct colocalization when sections immunostained for P2X7 were dual immunostained with antisera specific for microglia (Iba1, COX-1). In contrast, no colocalization was evident when sections were dual immunostained with P2X7 and GFAP, an astrocytic marker. In the latter experiment, dual ICC revealed two distinct cell populations with contrasting color demonstrating a population of distinct GFAP immunopositive cells and a population of distinct P2X7 immunopositive cells. We conclude that P2X7 antiserum used in this study is specific for and identifies microglia in rat and that there exists a timeline of progressive changes in microglia morphology that can be demonstrated following kainate-induced seizures. In addition, the morphological changes in microglia following seizure induction that can be identified with P2X7 antisera or with antisera specific for microglia suggest a neuroinflammatory milieu in areas of CNS seizure activity.


Subject(s)
Brain/metabolism , Encephalitis/metabolism , Epilepsy/metabolism , Gliosis/metabolism , Microglia/metabolism , Receptors, Purinergic P2/metabolism , Animals , Astrocytes/cytology , Astrocytes/metabolism , Biomarkers/metabolism , Brain/pathology , Brain/physiopathology , Calcium-Binding Proteins/metabolism , Convulsants , Cyclooxygenase 1/metabolism , Disease Models, Animal , Encephalitis/etiology , Encephalitis/physiopathology , Epilepsy/chemically induced , Epilepsy/physiopathology , Excitatory Amino Acid Agonists , Glial Fibrillary Acidic Protein/metabolism , Gliosis/etiology , Gliosis/physiopathology , Immunohistochemistry , Kainic Acid , Male , Membrane Proteins/metabolism , Microfilament Proteins , Microglia/cytology , Rats , Rats, Sprague-Dawley , Receptors, Purinergic P2X7
5.
Neuroscience ; 126(1): 105-14, 2004.
Article in English | MEDLINE | ID: mdl-15145077

ABSTRACT

Following neurological injury early in life numerous events, including excitotoxicity, neural degeneration, gliosis, neosynaptogenesis, and circuitry reorganization, may alone or in concert contribute to hyperexcitability and recurrent seizures in temporal lobe epilepsy. Our studies provide new evidence regarding the temporal sequence of key elements of hippocampal reorganization, mossy fiber sprouting and glutamate receptor subunit up-regulation, in a subset of young temporal lobe epileptic patients. Without evidence of mossy fiber sprouting, the youngest age group (3-10 years old) of mesial temporal lobe epileptic patients demonstrated enhanced glutamate receptor subunit profiles, suggesting that the dendritic change precedes axonal sprouting. However, sclerotic hippocampal specimens from epileptic patients ages 12-15 years old had the characteristic features of glutamate receptor up-regulation and mossy fiber sprouting first identified in the adult, indicating that reconstructed circuits appear early in the course of the disease. Non-sclerotic hippocampal specimens from lesion associated temporal lobe epileptic patients of all age groups showed minimal cell loss, sparse staining of glutamate receptor subunits in the dentate gyrus, and little or no mossy fiber sprouting. These compelling findings suggest a progressive sequence of events in the reorganization of the dentate gyrus of sclerotic hippocampal specimens. We suggest that cell loss and up-regulation of glutamate receptor subunits appear early in temporal lobe epilepsy and contribute to the synaptic plasticity that may facilitate the subsequent sprouting of mossy fiber collaterals which compound an already precipitous state of decline. The combination of pre-synaptic and post-synaptic changes serves as a potential substrate for hyperexcitability.


Subject(s)
Epilepsy, Temporal Lobe/metabolism , Epilepsy, Temporal Lobe/pathology , Mossy Fibers, Hippocampal/metabolism , Mossy Fibers, Hippocampal/pathology , Receptors, AMPA/metabolism , Adolescent , Age Factors , Child , Child, Preschool , Female , Humans , Male , Neuronal Plasticity
7.
Funct Neurol ; 15 Suppl 3: 19-27, 2000.
Article in English | MEDLINE | ID: mdl-11200790

ABSTRACT

The demonstration that nitrovasodilators act as nitric oxide (NO) donors has favored a resurgence of interest in this class of compounds. The demonstration of the different biological effects of NO in various districts, including the central nervous system, suggests a possible role for these substances besides their well-known cardiovascular activity. Among the various nitrovasodilators commercially available, nitroglycerin represents a well known substance to headache experts because of its capability to provoke spontaneous-like migraine attacks in headache-free migrainous subjects. Basic research has recently demonstrated that nitroglycerin activates a variegate set of brain nuclei following systemic administration via the intervention of selected neurotransmitters and neuromediators, with a specific time-pattern in different brain areas. Increasing evidence suggests that nitroglycerin-induced neuronal activation is mediated by multiple mechanisms that include direct neuronal and vascular action of nitroglycerin-derived and endogenously-synthesized NO, as well as indirect effects related to nitroglycerin-induced changes in cardiovascular and trigeminovascular systems. The study of the neurovascular effects of nitroglycerin in the rat provides relevant information for a better understanding of the pathophysiology of migraine attacks and of their triggers.


Subject(s)
Central Nervous System/drug effects , Nitric Oxide Donors/pharmacology , Nitroglycerin/pharmacology , Vasodilator Agents/pharmacology , Animals , Migraine Disorders/metabolism , Migraine Disorders/physiopathology , Nitric Oxide/metabolism , Rats
8.
Brain Res ; 842(2): 294-310, 1999 Sep 25.
Article in English | MEDLINE | ID: mdl-10526126

ABSTRACT

This study uses tract-tracing protocols to determine the circuitry of specific nuclei involved in nitroglycerin-induced activation. Combined retrograde and anterograde tracers were injected into nuclei which consistently demonstrate robust Fos expression following our systemic nitroglycerin injection paradigm. The nuclei, which conform to these criteria, that we have evaluated in this study are the locus coeruleus, parabrachial nucleus and paraventricular nucleus of the hypothalamus. Dual Fos/tracer immunocytochemistry in treated animals documented the existence of a subset of autonomic nuclei which are activated by nitroglycerin injection and have reciprocal connections. From the nature of this rich interconnection we suggest that nitroglycerin activates autonomic responses involved in cardiovascular pressor mechanisms. Nuclei which show strong Fos labeling following nitroglycerin administration, but not traced in this study, include the nucleus trigeminalis caudalis and the ventrolateral column of the periaqueductal gray, both of which mediate nociceptive modalities. These data confirm and expand on our previous findings and demonstrate that nitroglycerin activates a complex set of structures that are functionally and structurally interconnected to articulate an integrated response.


Subject(s)
Autonomic Nervous System/drug effects , Locus Coeruleus/drug effects , Mesencephalon/drug effects , Neurons/physiology , Nitroglycerin/pharmacology , Pain/physiopathology , Paraventricular Hypothalamic Nucleus/drug effects , Pons/drug effects , Animals , Autonomic Nervous System/physiology , Axonal Transport , Locus Coeruleus/physiology , Male , Mesencephalon/physiology , Neural Pathways/drug effects , Neural Pathways/physiology , Neural Pathways/physiopathology , Neurons/drug effects , Paraventricular Hypothalamic Nucleus/physiology , Phytohemagglutinins , Pons/physiology , Rats , Rats, Sprague-Dawley , Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate
9.
Schizophr Bull ; 25(3): 553-76, 1999.
Article in English | MEDLINE | ID: mdl-10478789

ABSTRACT

The Peters et al. Delusions Inventory (PDI) was designed to measure delusional ideation in the normal population, using the Present State Examination as a template. The multidimensionality of delusions was incorporated by assessing measures of distress, preoccupation, and conviction. Individual items were endorsed by one in four adults on average. No sex differences were found, and an inverse relationship with age was obtained. Good internal consistency was found, and its concurrent validity was confirmed by the percentages of common variance with three scales measuring schizotypy, magical ideation, and delusions. PDI scores up to 1 year later remained consistent, establishing its test-retest reliability. Psychotic inpatients had significantly higher scores, establishing its criterion validity. The ranges of scores between the normal and deluded groups overlapped considerably, consistent with the continuity view of psychosis. The two samples were differentiated by their ratings on the distress, preoccupation, and conviction scales, confirming the necessity for a multidimensional analysis of delusional thinking. Possible avenues of research using this scale and its clinical utility are highlighted.


Subject(s)
Delusions/diagnosis , Psychiatric Status Rating Scales , Psychometrics/methods , Superstitions , Thinking/classification , Adult , Aged , Chi-Square Distribution , Delusions/epidemiology , Delusions/psychology , England/epidemiology , Factor Analysis, Statistical , Female , Humans , Male , Middle Aged , Psychiatric Status Rating Scales/standards , Psychometrics/standards , Psychotic Disorders/psychology , Reference Values , Reproducibility of Results , Sampling Studies , Schizotypal Personality Disorder/psychology
10.
Prog Neurobiol ; 57(6): 607-24, 1999 Apr.
Article in English | MEDLINE | ID: mdl-10221784

ABSTRACT

Nitroglycerin is an organic nitrate that has been used as a vasodilator in the treatment of cardiac diseases for over a century. Only recently it has been demonstrated that the vasodilator effect of this drug depends upon the formation of nitric oxide in the blood vessel wall. However, clinical and research data gathered during the last decades have suggested that nitroglycerin possesses, besides its peripheral vasodilator effect, additional, puzzling biological activities. This organic nitrate compound provokes reflex cardiovascular activities via its interaction with the central sympathetic system. Its cerebrovascular effect, on the other hand, is probably mediated by the local release of neuropeptides. The direct application of nitroglycerin onto brain nuclei causes a prompt increase in the neuronal discharge rate. From a neurological point of view, nitroglycerin consistently induces a specific headache attack in patients suffering from migraine. Because of its temporal pattern and clinical characteristics, nitroglycerin-induced headache cannot be solely ascribed to the a drug-induced vasorelaxation. The demonstration that systemic nitroglycerin administration activates a widespread set of vegetative, nociceptive and neuroendocrine structures in the central nervous system seems to further support the occurrence of central mechanisms in the biological activity of nitroglycerin. Double labeling immunocytochemical and neuropharmacological studies have provided information on the putative neurotransmitters and neurochemical mechanisms involved in nitroglycerin-induced neuronal activation.


Subject(s)
Central Nervous System/drug effects , Nitroglycerin/pharmacology , Vasodilator Agents/pharmacology , Animals , Brain Mapping/methods , Cardiovascular System/drug effects , Cerebrovascular Circulation/drug effects , Humans , Neurons/drug effects
11.
Brain Behav Immun ; 12(2): 107-22, 1998 Jun.
Article in English | MEDLINE | ID: mdl-9646936

ABSTRACT

Cells of the immune system produce a variety of neuropeptides or peptide hormones, either constitutively or upon induction, and possess specific neuropeptide receptors that display ligand-receptor interactions similar to those described in the central nervous system (CNS). These findings suggest that specific subsets of lymphoid cells can produce and respond to peptides previously thought to be principally neural mediators. Recently, corticotropin releasing factor (CRF) mRNA was detected in the rat thymus and spleen, although the cells that synthesize CRF were not identified. We examined the localization of CRF and its mRNA in the rat spleen, thymus, and mesenteric lymph nodes using immunocytochemistry (ICC) and in situ hybridization (ISH), respectively. Immunoreactive CRF was present in cells in the marginal zone and red pulp of the spleen, in connective tissue septa and the subcapsular region of the thymus, and in the medullary cords and sinuses of the mesenteric lymph nodes. Dual ICC/ISH for CRF and its mRNA, respectively, demonstrated CRF mRNA over CRF-immunoreactive cells, suggesting CRF synthesis. Double-label ICC for CRF and markers for specific immunocyte subsets suggest that CRF+ cells in the spleen and thymus are macrophages. CRF+ cells in primary and secondary lymphoid organs reside in compartments that are innervated by sympathetic nerves, and some cells appears to be contacted by noradrenergic sympathetic nerve fibers, suggesting that CRF release may be influenced by the sympathetic nervous system, as it is in the hypothalamo-pituitary-adrenal axis. The presence of CRF in organs of the immune system suggests that this neuropeptide may modulate immune functions after paracrine release.


Subject(s)
Corticotropin-Releasing Hormone/metabolism , Lymph Nodes/metabolism , Spleen/metabolism , Thymus Gland/metabolism , Animals , Corticotropin-Releasing Hormone/genetics , Immunohistochemistry , In Situ Hybridization , Lymph Nodes/cytology , Male , Mesentery , RNA, Messenger/metabolism , Rats , Rats, Sprague-Dawley , Spleen/cytology , Thymus Gland/cytology , Tissue Distribution
12.
Br J Dermatol ; 136(3): 388-92, 1997 Mar.
Article in English | MEDLINE | ID: mdl-9115923

ABSTRACT

We report a man who presented in 1981 at the age of 30 with cutaneous lupus erythematosus (LE), which was resistant to a range of treatments over the subsequent 11 years. In 1991 he suffered fits, dysphasia and agitated depression, and in 1992 a severe septicaemic illness. Systemic LE was diagnosed, and investigation showed homozygous complement type 2 deficiency (C2d). Over a period of 30 months he has received 6 weekly fresh frozen plasma. Since starting this treatment his cutaneous disease has resolved and his depression, verbal fluency and psychomotor scores improved. We have not observed any adverse effects to this treatment and suggest it should be considered in similar patients.


Subject(s)
Complement C2/deficiency , Lupus Erythematosus, Systemic/complications , Plasma , Adult , Humans , Lupus Erythematosus, Systemic/pathology , Lupus Erythematosus, Systemic/therapy , Male , Nails/pathology , Skin/pathology
13.
Funct Neurol ; 12(5): 293-6, 1997.
Article in English | MEDLINE | ID: mdl-9439947

ABSTRACT

Systemic administration of ephedrine, an anti-hypotensive agent with central effects, induced dramatic expression of Fos protein in the caudate putamen (CPu) and subthalamic nucleus (STN) of rats. This may be related to dopaminergic agonist properties that have been attributed to this compound, dopamine receptors being present in both CPu and STN. This finding seems to suggest that central effects of ephedrine might be mediated by changes in basal ganglia outflow.


Subject(s)
Adrenergic Agonists/pharmacology , Caudate Nucleus/metabolism , Ephedrine/pharmacology , Proto-Oncogene Proteins c-fos/biosynthesis , Putamen/metabolism , Thalamic Nuclei/metabolism , Animals , Caudate Nucleus/drug effects , Male , Putamen/drug effects , Rats , Rats, Sprague-Dawley , Thalamic Nuclei/drug effects
14.
Neuropharmacology ; 36(10): 1417-24, 1997 Oct.
Article in English | MEDLINE | ID: mdl-9423929

ABSTRACT

Nitroglycerin is a nitric oxide donor which induces sustained expression of Fos protein, a marker of neuronal activation, in specific neuronal groups in the central nervous system. The mechanisms which underlie nitroglycerin-induced neuronal activation are elusive at this time, although a precise role has been suggested for the pool of neurons containing nitric oxide synthase as well as for catecholaminergic and peptidergic pathways. The aim of this study was to provide further details on the central effect of nitroglycerin by means of a pharmacological manipulation of nitroglycerin-induced neuronal activation with inhibitors of the nitric oxide synthase, modulators of the sympathetic drive and mediators of pain perception. Adult male Sprague-Dawley rats received L-NGnitro-arginine methyl ester, 7-nitro-indazole, ephedrine sulfate, indomethacin, capsaicin or vehicle before the subcutaneous injection of nitroglycerin (10 mg/kg b.w.). They were sacrificed 4 hr after nitroglycerin administration and brain sections were processed for immunocytochemical visualization of Fos. All the pharmacological treatments administered before injecting nitroglycerin selectively influenced Fos expression in the different brain nuclei. The data obtained suggest that nitroglycerin-induced neuronal activation is mediated by nociceptive and barosensitive mechanisms. Nitric oxide seems to represent the most important mediator of this phenomenon. The sympathetic system and prostaglandin synthesis are also likely to be involved.


Subject(s)
Neurons/drug effects , Nitric Oxide Synthase/antagonists & inhibitors , Nitric Oxide/metabolism , Nitroglycerin/pharmacology , Vasodilator Agents/pharmacology , Animals , Capsaicin/pharmacology , Central Nervous System Stimulants/pharmacology , Cyclooxygenase Inhibitors/pharmacology , Enzyme Inhibitors/pharmacology , Ephedrine/pharmacology , Hippocampus/drug effects , Indomethacin/pharmacology , Male , NG-Nitroarginine Methyl Ester/pharmacology , Rats , Rats, Sprague-Dawley
15.
Epilepsia ; 37(11): 1081-7, 1996 Nov.
Article in English | MEDLINE | ID: mdl-8917058

ABSTRACT

PURPOSE: We wished to identify immunocytochemically the distribution of proopiomelanocortin-related peptides in the hippocampal formation of patients with epilepsy. METHODS: Surgical hippocampal specimens from temporal lobe epilepsy (TLE) patients and autopsy control tissue were examined immunocytochemically for ACTH, alpha-melanocyte-stimulating hormone (alpha-MSH) and beta-endorphin. RESULTS: There was a dense distribution of ACTH-immunoreactive neurons in the hippocampal formation of patients with mesial TLE syndrome (MTLE). These hippocampal specimens showed significant cell loss. ACTH-positive neurons were most prominent in the subiculum, with scattered ACTH-immunoreactive neuronal elements distributed in the cornu ammonis fields and hilus. Light ACTH immunoreactivity was detected in the tumor-related epileptic hippocampal specimens, which showed minimal cell loss. Although autopsy control tissue from the hypothalamus showed intense ACTH staining patterns in cells and fibers, there was little or no ACTH immunoreactivity in the autopsy hippocampal tissue. The expression of ACTH immunoreactive elements was correlated with patterns of cell loss. No alpha-MSH- or beta-endorphin-immunoreactive neurons were detected in any of the hippocampal specimens. CONCLUSIONS: ACTH has anticonvulsant properties, and its novel expression in the glutamatergic subicular neurons, which provide the main outflow of the hippocampal formation, may represent an attempt by the damaged hippocampal circuit to restore the balance of excitatory/inhibitory neurotransmission in TLE.


Subject(s)
Adrenocorticotropic Hormone/immunology , Epilepsy, Temporal Lobe/immunology , Hippocampus/immunology , Autopsy , Cell Count , Epilepsy, Temporal Lobe/pathology , Hippocampus/pathology , Humans , Immunohistochemistry , Neurons/immunology , alpha-MSH/immunology , beta-Endorphin/immunology
19.
Neuroscience ; 72(1): 15-29, 1996 May.
Article in English | MEDLINE | ID: mdl-8730702

ABSTRACT

The immunocytochemical distribution of the AMPA-selective receptor subunits GluR1 and GluR2/3 were mapped in the human hippocampal formation obtained from surgery for medically intractable temporal lobe epilepsy. GluR2/3 immunoreactivity was detected in all principal cell types of the hippocampal formation, including hilar neurons, granule cells of the dentate gyrus, and pyramidal cells of the cornu ammonis fields and subiculum. GluR2/3 immunostaining typically filled the cell bodies and processes of neurons. A comparison of GluR2/3 immunoreactivity in a sclerotic specimen versus a non-sclerotic specimen demonstrated a profound loss of staining, specifically in the areas where neuronal dropout was occurring, including CA1, CA3 and the hilus. An analysis of GluR1 immunoreactivity in non-sclerotic specimens revealed that it was predominantly localized to cellular processes throughout the cornu ammonis fields, with a sparse staining of the dentate gyrus outer molecular layer and little to no staining of the dentate gyrus inner molecular layer. Similar to the GluR2/3-immunostained patterns, GluR1 immunoreactivity was lost in the cornu ammonis fields of sclerotic hippocampal specimens, corresponding to patterns of neuronal dropout. Our most compelling finding was a unique extensive pattern of GluR1 and Glu2/3 immunoreactivity throughout the molecular layers of the dentate gyrus of severely compromised hippocampi. The altered staining of GluR1 and GluR2/3 complements some of the patterns of axonal sprouting already described for the dentate gyrus, with a conjecture that their anatomy and distribution pattern underlies to some degree the reorganization of the sclerotic hippocampus. A combination of enhanced glutamatergic transmission and changes in neuropeptides that modulate hippocampal circuitry could greatly affect the degree of excitability in the hippocampal formation. The alterations of GluR1 and GluR2/3 immunoreactivity in the dentate gyrus add another component to the concept of reorganization in the epileptic sclerotic hippocampus.


Subject(s)
Epilepsy, Temporal Lobe/metabolism , Hippocampus/metabolism , Receptors, AMPA/metabolism , Adolescent , Adult , Dentate Gyrus/metabolism , Dentate Gyrus/pathology , Electroencephalography , Electrophysiology , Epilepsy, Temporal Lobe/pathology , Hippocampus/pathology , Humans , Immunohistochemistry , Magnetic Resonance Imaging , Middle Aged , Nerve Net/metabolism , Nerve Net/pathology
20.
Peptides ; 17(3): 443-9, 1996.
Article in English | MEDLINE | ID: mdl-8735971

ABSTRACT

In this study, we carried out an immunohistochemical evaluation of the neurochemical characteristics of neurons that are activated (i.e., express Fos protein) in response to systemic administration of nitroglycerin. In the brain stem, a significant percentage of activated neurons contained noradrenaline as a neurotransmitter, whereas only a few of them contained serotonin. In the paraventricular and supraoptic nuclei of the hypothalamus, numerous Fos-immunoreactive neurons were also positive for vasopressin, oxytocin, and corticotropin-releasing factor. Codistribution with corticotropin-releasing factor was also observed in the central nucleus of the amygdala. Our findings point out a prominent role for catecholaminergic and peptidergic pathways in the brain in response to systemic nitroglycerin.


Subject(s)
Brain/drug effects , Neural Pathways/drug effects , Nitroglycerin/pharmacology , Vasodilator Agents/pharmacology , Animals , Brain/cytology , Brain Stem/cytology , Brain Stem/drug effects , Catecholamines/isolation & purification , Immunohistochemistry , Male , Neurons/chemistry , Neuropeptides/isolation & purification , Prosencephalon/cytology , Prosencephalon/drug effects , Proto-Oncogene Proteins c-fos/isolation & purification , Rats , Rats, Sprague-Dawley
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