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1.
In. Arias, SJ; Armando, G; Armando, G; Landra, F; Mavar, C; Silva, D; Wustten, S. Enfermedad pulmonar obstructiva crónica en el primer nivel de atención: magnitud y características de los casos y de la atención. Ciudad Autónoma de Buenos Aires, Ministerio de Salud de la Nación. Dirección de Investigación en Salud, 2018. p.1-1.
Non-conventional in Spanish | ARGMSAL, BINACIS | ID: biblio-1452177

ABSTRACT

INTRODUCCIÓN La esclerosis lateral amiotrófica (ELA) es una enfermedad neurodegenerativa, que causa el deterioro de las neuronas motoras superiores e inferiores y lleva a la muerte al 50% de los enfermos en los primeros 3 años posteriores al diagnóstico, siendo la más frecuente de estas condiciones en los adultos. Se estima que la tasa de incidencia de la ELA para todas las edades es de 1,6 personas por cada 100.000 habitantes, cifra que aumenta a 5 personas por cada 100.000 en la séptima década de la vida. La incidencia estimada en Argentina es de 2 por 100.000 habitantes por año, pero no existen cifras oficiales. La ELA no es una enfermedad de declaración obligatoria a nivel nacional, por cuya razón surge la necesidad de realizar un estudio que describa el comportamiento de la enfermedad en el país. OBJETIVOS A nivel general, desarrollar e implementar como prueba piloto el Registro Nacional de Esclerosis Lateral Amiotrófica (ReNELA) en Argentina. De manera específica, construir y consolidar una base de datos unificada para los efectores involucrados, realizar un análisis epidemiológico descriptivo de la base de datos construida y evaluar el registro y su alcance respecto de la población afectada en el período seleccionado. MÉTODOS Se elaboró un registro anónimo, que incluyó a pacientes vivos con residencia en el territorio nacional y diagnóstico de ELA basado en historias clínicas. El instrumento fue una base de datos construida para volcar los datos pertinentes al registro y analizarlos posteriormente. RESULTADOS Se logró construir una base con datos de 215 personas que padecen ELA. Dado que se estudió a la población alcanzada por la red de neurólogos y no fue posible tomar una muestra representativa, no cabe realizar inferencias estadísticas generalizables a la población del país. DISCUSIÓN Esta experiencia permitió identificar posibles factores que facilitarían la consolidación del registro y su continuidad para establecerse como una herramienta capaz de caracterizar epidemiológicamente la ELA en el país.


Subject(s)
Epidemiology , Surveillance in Disasters , Amyotrophic Lateral Sclerosis
3.
Am J Infect Control ; 28(5): 333-9, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11029131

ABSTRACT

PURPOSE: To study retrospectively the incidence of ventilator-associated pneumonia (VAP) at the time of Pseudomonas aeruginosa nosocomial bloodstream infection (BSI) and at the time of P aeruginosa airway colonization. MATERIALS AND METHODS: Fifteen very low-birth-weight infants who had P aeruginosa BSI and 33 others who did not but who had P aeruginosa airway-colonization were studied. We correlated clinical data, blood cultures (BCs), and tracheal cultures (TCs) with radiologic findings from radio-graphs taken within 2 days before, the day of, and 1 day after BCs or TCs were first positive for P aeruginosa. Chest radiographs were graded by using semiquantitative scores for bronchopulmonary dysplasia and for pneumonia. RESULTS: Mean birth weight, gestational age, and age when BC or TC became positive were similar for patients with BSI and colonization. At the time of BSI, 2 infants had airway colonization with P aeruginosa; the TCs of the remaining 13 grew P aeruginosa as a new pathogen. Thirteen of 15 patients with BSI, but none of 33 infants with colonization, died within 2 days of positive BC. VAP was diagnosed in 13 of 15 patients with BSI and in 3 of 33 infants with colonization. CONCLUSION: Mechanically ventilated very low-birth-weight infants whose TCs yield P aeruginosa but whose BCs remain negative infrequently have VAP are presumed airway-colonized and are expected to survive. Conversely, VAP is likely to be found when BCs and TCs simultaneously grow P aeruginosa, and high mortality is anticipated.


Subject(s)
Cross Infection/epidemiology , Infant, Very Low Birth Weight , Pneumonia/etiology , Pseudomonas aeruginosa/isolation & purification , Respiration, Artificial/adverse effects , Birth Weight , Cross Infection/blood , Electrophoresis, Gel, Pulsed-Field , Equipment Contamination , Female , Gestational Age , Hospital Records , Humans , Incidence , Infant, Newborn , Intensive Care Units, Neonatal , Male , Ohio/epidemiology , Pneumonia/epidemiology , Pneumonia/microbiology , Retrospective Studies , Trachea/microbiology
4.
Eur J Neurosci ; 12(8): 2676-84, 2000 Aug.
Article in English | MEDLINE | ID: mdl-10971611

ABSTRACT

Conditioned media from embryonic mixed cells from the rat brain were used in a chemotaxis assay to look for potential chemotactic activity which could account for the infiltration of the developing central nervous system (CNS) by macrophage precursors. The most potent chemotactic activity was found in the conditioned medium from E17 mixed brain cells (E17-CM). Based upon checkerboard analysis, this activity was shown to be chemotactic rather than chemokinetic. This chemoattraction was not restricted to brain macrophages (BM) because it was as pronounced on bone marrow-derived macrophages. The implication of a peptide compound in this activity was suggested by its resistance to heat as well as acid treatments, and by its sensitivity to aminopeptidase M digestion. In agreement with the opioid nature of the peptide, not only naloxone, but also the delta opioid receptor antagonist ICI-174 reduced the migration of BM in response to E17-CM by 60%. This migratory activity was no longer effective when pertussis toxin-treated BM were used. When the chemotactic effects of selective opioid agonists were compared to that of E17-CM, DPDPE, the delta agonist, was the most efficient in attracting BM. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis indicated that delta as well as other known opioid receptors were expressed in both BM and E17 mixed brain cells. Finally, a Met-enkephalin-like reactivity was found by RIA in the E17-CM. Altogether, these observations suggest that a delta-like opioid peptide released from embryonic mixed brain cells could be responsible for the infiltration of the developing CNS by macrophages precursors.


Subject(s)
Brain/embryology , Chemotaxis, Leukocyte/physiology , Macrophages/cytology , Microglia/cytology , Opioid Peptides/metabolism , Analgesics, Opioid/pharmacology , Animals , Brain/cytology , Cells, Cultured , Chemotaxis, Leukocyte/drug effects , Culture Media, Conditioned/pharmacology , Enkephalin, D-Penicillamine (2,5)-/pharmacology , Gene Expression Regulation, Developmental , Naloxone/pharmacology , Narcotic Antagonists/pharmacology , Oligonucleotide Probes , Oligopeptides/pharmacology , Opioid Peptides/analysis , RNA, Messenger/analysis , Rats , Receptors, Opioid, delta/antagonists & inhibitors , Receptors, Opioid, delta/genetics , Stem Cells/cytology
5.
Biochem J ; 348 Pt 1: 119-28, 2000 May 15.
Article in English | MEDLINE | ID: mdl-10794722

ABSTRACT

In brain, focal adhesion kinase (FAK) is regulated by neurotransmitters and has a higher molecular mass than in other tissues, due to alternative splicing. Two exons code for additional peptides of six and seven residues ('boxes' 6 and 7), located on either side of Tyr(397), which increase its autophosphorylation. Using in situ hybridization and a monoclonal antibody (Mab77) which does not recognize FAK containing box 7, we show that, although mRNAs coding for boxes 6 and 7 have different patterns of expression in brain, FAK+6,7 is the main isoform in forebrain neurons. The various FAK isoforms fused to green fluorescent protein were all targeted to focal adhesions in non-neuronal cells. Phosphorylation-state-specific antibodies were used to study in detail the phosphorylation of Tyr(397), a critical residue for the activation and function of FAK. The presence of boxes 6 and 7 increased autophosphorylation of Tyr(397) independently and additively, whereas they had a weak effect on FAK kinase activity towards poly(Glu,Tyr). Src-family kinases were also able to phosphorylate Tyr(397) in cells, but this phosphorylation was decreased in the presence of box 6 or 7, and abolished in the presence of both. Thus the additional exons characteristic of neuronal isoforms of FAK do not alter its targeting, but change dramatically the phosphorylation of Tyr(397). They increase its autophosphorylation in vitro and in transfected COS-7 cells, whereas they prevent its phosphorylation when co-transfected with Src-family kinases.


Subject(s)
Isoenzymes/metabolism , Protein-Tyrosine Kinases/metabolism , Tyrosine/metabolism , src-Family Kinases/metabolism , Alternative Splicing , Animals , Antibodies/immunology , Astrocytes/physiology , Brain/enzymology , Brain/metabolism , COS Cells , Escherichia coli , Focal Adhesion Kinase 1 , Focal Adhesion Protein-Tyrosine Kinases , Neurons/physiology , Phosphorylation , Precipitin Tests , Rats , Recombinant Proteins/metabolism
6.
AJR Am J Roentgenol ; 172(4): 1033-8, 1999 Apr.
Article in English | MEDLINE | ID: mdl-10587143

ABSTRACT

OBJECTIVE: HIV-positive individuals commonly have symptoms of airway disease. We evaluated thin-section CT scans of HIV-infected individuals during inspiration and expiration for evidence of focal air trapping. We also correlated imaging findings with pulmonary function test results. SUBJECTS AND METHODS: Fifty-nine subjects, 48 of whom were HIV-positive and 11 of whom were HIV-negative, underwent thin-section CT of the thorax during inspiration and expiration. All subjects also underwent pulmonary function tests. Two radiologists, who were unaware of the subjects' HIV status and smoking history and of the results of pulmonary function tests, evaluated the CT scans for the presence and severity of focal air trapping. RESULTS: Expiratory CT revealed focal air trapping in 33 subjects: 30 were HIV-positive and three were HIV-negative (p = .0338). The mean values of forced expiratory volume in 1 sec (FEV1), forced mid expiratory flow, and diffusion capacity (DL(CO)) were significantly lower for subjects with focal air trapping (mean = 88.85, 84.52, and 80.80, respectively) than for those with normal findings on CT (mean = 100.84, 99.24, and 95.82, respectively; p = .001, p = .021, and p = .003, respectively). We found no significant differences in smoking history between HIV-positive and HIV-negative subjects. Severe air trapping on expiratory CT scans was seen in three subjects: All three had HIV infection, low CD4 counts, and abnormally decreased FEV1 and DL(CO) values. CONCLUSION: Focal air trapping was a common finding on thoracic CT scans obtained during expiration in HIV-positive subjects. In addition, focal air trapping was associated with significantly lower FEV1, forced mid expiratory flow, and DL(CO) values than those found for subjects in whom CT revealed no focal air trapping. These results suggest that small airways disease may accompany a decline in pulmonary function in HIV-positive individuals.


Subject(s)
HIV Infections/diagnostic imaging , Lung/diagnostic imaging , Respiratory Mechanics , Tomography, X-Ray Computed , Adult , Female , Forced Expiratory Volume , HIV Infections/physiopathology , Humans , Male , Maximal Midexpiratory Flow Rate , Pulmonary Diffusing Capacity
7.
Radiology ; 213(1): 135-40, 1999 Oct.
Article in English | MEDLINE | ID: mdl-10540653

ABSTRACT

PURPOSE: To evaluate the rate of complications associated with diagnostic cerebral angiography accompanied by intraarterial chemotherapy for the treatment of primary and metastatic brain tumors. MATERIALS AND METHODS: Three hundred ninety-two consecutive transfemoral cerebral angiographic procedures accompanied by intraarterial chemotherapy were performed in 48 patients (28 men, 20 women), and complications were evaluated. RESULTS: The most common local complications were groin hematomas, which occurred in 10 (2.6%) of the 392 procedures and none of which required therapy. Two carotid arterial dissections (0.5%) were reported in two patients who were asymptomatic and did not require further treatment. Both improved at follow-up examinations. Only one patient required surgery for a delayed popliteal embolus. Systemic transient complications occurred five times (1.3%). There were seven (1.8%) transient neurologic events, which were paresis and visual disturbances. Six (1.5%) transient seizure events were recorded. There were no permanent neurologic complications. CONCLUSION: Intraarterial chemotherapy for brain tumors is a safe procedure with a low complication rate.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Brain Neoplasms/diagnostic imaging , Cerebral Angiography/adverse effects , Infusions, Intra-Arterial/adverse effects , Adolescent , Adult , Aged , Aged, 80 and over , Brain Neoplasms/drug therapy , Carotid Artery, Internal , Child , Female , Humans , Male , Middle Aged , Radiography, Interventional , Vertebral Artery
8.
Biochemistry ; 37(42): 14823-32, 1998 Oct 20.
Article in English | MEDLINE | ID: mdl-9778356

ABSTRACT

The innervation of embryonic skeletal muscle cells is marked by the redistribution of nicotinic acetylcholine receptors (AChRs) on muscle surface membranes into high-density patches at nerve-muscle contacts. To investigate the role of protein phosphorylation pathways in the regulation of AChR surface distribution, we have identified the sites on AChR delta-subunits that undergo phosphorylation associated with AChR cluster dispersal in cultured myotubes. We found that PKC-catalyzed AChR phosphorylation is targeted to Ser378, Ser393, and Ser450, all located in the major intracellular domain of the AChR delta-subunit. Adjacent to one of these sites is a PKA consensus target site (Ser377) that was efficiently phosphorylated by purified PKA in vitro. The PKC activator 12-O-tetradecanoylphorbol-13-acetate (TPA) and the phosphoprotein phosphatase inhibitor okadaic acid (OA) produced increased phosphorylation of AChR delta-subunits on the three serine residues that were phosphorylated by purified PKC in vitro. In contrast, treatment of these cells with the PKA activator forskolin, or with the cell-permeable cAMP analogue 8-bromo-cAMP, did not alter the phosphorylation state of surface AChR, suggesting that PKA does not actively phosphorylate the delta-subunit in intact chick myotubes. The effects of TPA and OA included an increase in the proportion of surface AChR that is extracted in Triton X-100, as well as the spreading of AChR from cluster regions to adjacent areas of the muscle cell surface. These findings suggest that PKC-catalyzed phosphorylation on the identified serine residues of AChR delta-subunits may play a role in the surface distribution of these receptors.


Subject(s)
Muscle, Skeletal/metabolism , Receptors, Nicotinic/metabolism , Amino Acid Sequence , Amino Acids/analysis , Animals , Binding Sites/drug effects , Cell Membrane/drug effects , Cell Membrane/metabolism , Cells, Cultured , Chick Embryo , Cyclic AMP-Dependent Protein Kinases/isolation & purification , Cyclic AMP-Dependent Protein Kinases/metabolism , Molecular Sequence Data , Muscle, Skeletal/chemistry , Octoxynol , Okadaic Acid/pharmacology , Peptide Mapping , Phosphorylation/drug effects , Protein Kinase C/isolation & purification , Protein Kinase C/metabolism , Receptors, Nicotinic/chemistry , Tetradecanoylphorbol Acetate/pharmacology
9.
Glia ; 24(2): 180-6, 1998 Oct.
Article in English | MEDLINE | ID: mdl-9728764

ABSTRACT

Intraparenchymal migration of macrophages occurs in the CNS during development or as a consequence of tissue injuries. In the present study, we have shown, by using an in vitro chemotaxis assay, that cultured rat astrocytes obtained from the developing cerebral cortex and striatum produce soluble factors, which attract purified brain macrophages. The effect of astrocyte-derived factors on macrophages was strongly reduced in the presence of antibodies neutralizing colony-stimulating factor 1 (CSF-1, also called M-CSF), and recombinant CSF-1 was found to act as a chemotactic agent on brain macrophages. Synthesis of CSF-1 by cultured astrocytes was confirmed by northern detection of CSF-1 transcripts. In contrast, the CSF-1 gene was not expressed by cultured neurons from the cerebral cortex and striatum or by the brain macrophage population responsive to CSF-1 gradient. ELISA detection of CSF-1 in tissue extracts revealed the occurrence of this cytokine in the rat cerebral cortex during postnatal development and in adults. Altogether, our results demonstrate that astrocytes, through CSF-1 secretion, can trigger the polarized migration of brain macrophages and suggest a new mechanism which could regulate the locomotion of these cells in the cerebral cortex during ontogenesis or following lesions.


Subject(s)
Astrocytes/metabolism , Brain/cytology , Macrophage Colony-Stimulating Factor/biosynthesis , Macrophage Colony-Stimulating Factor/physiology , Macrophages/metabolism , Animals , Blotting, Northern , Brain Chemistry/physiology , Cell Division/physiology , Cell Movement/physiology , Cell Survival/physiology , Cells, Cultured , Chemotaxis, Leukocyte/physiology , Cytokines/biosynthesis , Enzyme-Linked Immunosorbent Assay , Humans , Neurons/metabolism , Rats
10.
Aust N Z J Psychiatry ; 32(2): 307-8, 1998 Apr.
Article in English | MEDLINE | ID: mdl-9588317
11.
J Biol Chem ; 273(7): 3909-14, 1998 Feb 13.
Article in English | MEDLINE | ID: mdl-9461575

ABSTRACT

We have isolated a full-length murine clone corresponding to the rat neuronal p1A75 partial cDNA (Sutcliffe, J. G., Milner, R. J., Shinnick, T. M., and Bloom, F. E. (1983) Cell 33, 671-682). It encodes a 185-residue polypeptide that displays 56% identity with p19, a protein selectively expressed in the Golgi apparatus of neural cells (Sabéran-Djoneidi, D., Marey-Semper, I., Picart, R., Studler, J.-M., Tougard, C., Glowinski, J., and Lévi-Strauss, M. (1995) J. Biol. Chem. 270, 1888-1893). An antibody directed against the recombinant polypeptide allowed us to demonstrate the existence of the natural 21-kDa protein (p21) in brain and its prominent juxtanuclear Golgi-like localization in cultured neurons. Ultrastructural observation of cultured neurons and analysis of transfected COS cells revealed a specific labeling of the Golgi apparatus, suggesting, as for p19, the presence of a Golgi targeting signal in its primary sequence. Surprisingly, p21, which is much more strongly expressed in the olfactory epithelium than p19, is also present in the Golgi complex of spermatocytes and in the flagellar middle piece of late spermatids.


Subject(s)
Golgi Apparatus/chemistry , Peptides/chemistry , Amino Acid Sequence , Animals , Base Sequence , COS Cells/ultrastructure , Cloning, Molecular , Germ Cells/chemistry , Germ Cells/ultrastructure , In Situ Hybridization , Male , Mice , Molecular Sequence Data , Nerve Tissue Proteins/chemistry , Neurons/chemistry , Neurons/ultrastructure , RNA, Messenger/analysis , Rats , Sequence Alignment , Sequence Analysis, DNA , Testis/chemistry , Testis/cytology
12.
J Biol Chem ; 272(46): 28925-32, 1997 Nov 14.
Article in English | MEDLINE | ID: mdl-9360963

ABSTRACT

The muscle-type nicotinic acetylcholine receptor (AChR)2 is a pentameric membrane ion channel assembled in the endoplasmic reticulum from four homologous subunits by mechanisms that are insufficiently understood. Nascent AChR subunits were recently found to form complexes with the endoplasmic reticulum-resident molecular chaperone calnexin. To determine the contribution of this interaction to AChR assembly and surface expression, we have now used transient transfection of mouse AChR subunits and calnexin into non-muscle cells. Co-transfection of calnexin along with AChR subunits into COS and HEK 293 cells was found to enhance AChR subunit folding and assembly, and to decrease degradation rates of newly synthesized AChR alpha-subunits, resulting in elevated surface expression of assembled AChR. Moreover, inhibition of the interaction between endogenous calnexin and AChR by castanospermine resulted in decreased AChR subunit folding, assembly, and surface expression in muscle and HEK 293 cells. Together, these findings provide evidence that calnexin directly contributes to AChR biogenesis by promoting subunit folding and assembly.


Subject(s)
Calcium-Binding Proteins/physiology , Receptors, Nicotinic/metabolism , Animals , COS Cells , Calnexin , Cell Line , Cell Membrane/metabolism , Humans , Indolizines/pharmacology , Mice , Protein Folding , Transfection
13.
J Biol Chem ; 272(45): 28720-5, 1997 Nov 07.
Article in English | MEDLINE | ID: mdl-9353341

ABSTRACT

pp125 focal adhesion kinase (FAK), a cytoplasmic tyrosine kinase transducing signals initiated by integrin engagement and G protein-coupled receptors, is highly expressed in brain. FAK from brain had a higher molecular weight and an increased autophosphorylation activity, than from other tissues. In addition to a 9-base insertion in the 3'-coding region, which defines FAK+, rat striatal FAK mRNAs contained several additional short exons, coding for peptides of 28, 6, and 7 residues, respectively (termed boxes 28, 6, and 7), surrounding the autophosphorylated Tyr-397. In transfected COS 7 cells, the presence of boxes 6 and 7 conferred an increased overall tyrosine phosphorylation, a higher phosphorylation of Tyr-397 assessed with a phosphorylation state-specific antibody, and a more active autophosphorylation in immune precipitates. The presence of box 28 did not alter further these parameters. Two-dimensional phosphopeptide maps of hippocampal FAK were identical to those of FAK+6,7. The presence of the various exons did not alter the interaction of FAK with c-Src, n-Src, or Fyn. Thus, several splice isoforms of FAK are preferentially expressed in rat brain, some of which have an increased autophosphorylation activity, suggesting that FAK may have specific properties in neurons.


Subject(s)
Alternative Splicing , Brain/enzymology , Cell Adhesion Molecules/genetics , Protein-Tyrosine Kinases/genetics , Receptor, Insulin/genetics , Amino Acid Sequence , Animals , Base Sequence , COS Cells , Cell Adhesion Molecules/metabolism , Focal Adhesion Kinase 1 , Focal Adhesion Protein-Tyrosine Kinases , Isoenzymes/genetics , Isoenzymes/metabolism , Mice , Molecular Sequence Data , Peptide Mapping , Phosphorylation , Protein-Tyrosine Kinases/metabolism , RNA, Messenger/metabolism , Rats , Receptor, Insulin/metabolism
14.
Cent Afr J Med ; 43(8): 213-9, 1997 Aug.
Article in English | MEDLINE | ID: mdl-9431757

ABSTRACT

OBJECTIVE: To determine the trends of the 10 most common diseases in the Medical Department. DESIGN: Retrospective descriptive study of patients' discharge summaries. SETTING: United Bulawayo Hospital, tertiary level hospital and referral centre for district hospitals. SUBJECTS: All patients admitted and discharged from the medical wards from 1987 to 1994, excluding all those who died. MAIN OUTCOME MEASURES: Number of discharges, patients' origin, paying status, diagnoses, staffing levels, reasons for transfer out. RESULTS: The top 10 diseases encountered in 12,280 patients were: pneumonia, HIV/AIDS, pulmonary tuberculosis, hypertension, Diabetes mellitus, malaria, gastro-enteritis, congestive cardiac failure secondary to cardiomyopathy, congestive cardiac failure secondary to hypertension, and asthma. They respectively accounted for 11% and 49% of all hospital and departmental admissions. Most disease prevalences increased from 1987 to 1994, with HIV/AIDS showing the sharpest rise. Tuberculosis was the most frequent disease and hypertension proved to be the leading non communicable disease. A positive diagnosis was made in 76% of cases. Patients' median age was 37 years and sex ratio M/F was 1.7:1. Staffing levels and bed capacity remained unchanged despite an increasing number of patients. Of these, 22% came from rural areas and 77% with low incomes did not pay for services. Transfers out effected mainly for special diagnostic procedures accounted for 0.2%. CONCLUSIONS: Infections and cardiovascular diseases alone accounted for 50% of the diagnoses made in patients discharged from the Medical Department of United Bulawayo Hospitals from 1987 to 1994. The 10 commonest diseases accounted for 49% of the morbidity and most of them increased in frequencies, while in case of HIV/AIDS, the increase was six fold. Cardiovascular diseases showed unexpectedly high prevalences. Diagnoses were confirmed in 76% of cases. The main problem encountered was multi pathology mainly due to added super infections and inability of 77% of patients to afford adequate health care. They resulted in frequent readmissions, heavy workload and high costs which threatened the quality of care.


Subject(s)
Morbidity/trends , Patient Discharge/trends , Adolescent , Adult , Aged , Aged, 80 and over , Child , Family Practice , Female , Hospital Departments , Hospitals, District , Humans , Male , Middle Aged , Prevalence , Referral and Consultation , Retrospective Studies , Zimbabwe/epidemiology
15.
J Neurosci ; 17(14): 5305-15, 1997 Jul 15.
Article in English | MEDLINE | ID: mdl-9204915

ABSTRACT

The infiltration of bone marrow-derived macrophages into the CNS contributes to growth and reactions of microglia during development or after brain injury. The proliferation of microglial cells is stimulated by colony-stimulating factor 1 (CSF-1), an astrocyte-produced growth factor that acts on mononuclear phagocytes. In the present study, we have shown, using an in vitro model system, that rodent neurons obtained from the developing cerebral cortex produce a soluble factor that strongly enhances the proliferation of macrophages cultured in the presence of CSF-1. Both macrophages isolated from the developing brain and those from the adult bone marrow were stimulated. Kinetic analyses of [3H]thymidine incorporation into macrophages indicated that their response to the neuron-derived factor involved a shortening of the cycle of proliferating cells. The effect of neurons on macrophages was blocked in the presence of antibodies neutralizing transforming growth factor-beta2 (TGF-beta2), whereas recombinant TGF-beta2 stimulated macrophage proliferation in the presence of CSF-1. Neuronal secretion of TGF-beta2 was confirmed by reverse transcription-PCR detection of TGF-beta2 transcripts and immunodetection of the protein within neurons and in their culture medium. In situ hybridization and immunohistochemical experiments showed neuronal expression of TGF-beta2 in sections of cerebral cortex obtained from 6-d-old rats, an age at which extensive developmental recruitment of macrophages occurs in this cerebral region. Altogether, our results provide direct evidence that neurons have the capacity to promote brain macrophage proliferation and demonstrate the role of TGF-beta2 in this neuronal function.


Subject(s)
Cell Count/drug effects , Cell Division/drug effects , Macrophages/drug effects , Neurons/physiology , Transforming Growth Factor beta/pharmacology , Animals , Cells, Cultured , Dose-Response Relationship, Drug , Humans , Male , Rats , Rats, Sprague-Dawley
16.
Science ; 273(5282): 1719-22, 1996 Sep 20.
Article in English | MEDLINE | ID: mdl-8781236

ABSTRACT

Anandamide is an endogenous ligand for central cannabinoid receptors and is released after neuronal depolarization. Anandamide increased protein tyrosine phosphorylation in rat hippocampal slices and neurons in culture. The action of anandamide resulted from the inhibition of adenylyl cyclase and cyclic adenosine 3', 5'-monophosphate-dependent protein kinase. One of the proteins phosphorylated in response to anandamide was an isoform of pp125-focal adhesion kinase (FAK+) expressed preferentially in neurons. Focal adhesion kinase is a tyrosine kinase involved in the interactions between the integrins and actin-based cytoskeleton. Thus, anandamide may exert neurotrophic effects and play a role in synaptic plasticity.


Subject(s)
Arachidonic Acids/pharmacology , Cell Adhesion Molecules/metabolism , Hippocampus/enzymology , Neurons/enzymology , Protein-Tyrosine Kinases/metabolism , Adenylyl Cyclase Inhibitors , Adenylyl Cyclases/metabolism , Amino Acid Sequence , Animals , Arachidonic Acid/pharmacology , Cell Line , Cells, Cultured , Cyclic AMP/metabolism , Cyclic AMP-Dependent Protein Kinases/antagonists & inhibitors , Cyclic AMP-Dependent Protein Kinases/metabolism , Endocannabinoids , Focal Adhesion Kinase 1 , Focal Adhesion Protein-Tyrosine Kinases , Hippocampus/drug effects , In Vitro Techniques , Molecular Sequence Data , Neuronal Plasticity/drug effects , Neurons/drug effects , Phosphorylation , Phosphotyrosine/metabolism , Polyunsaturated Alkamides , Prosencephalon , Rats , Receptors, Cannabinoid , Receptors, Drug/metabolism
17.
Eur J Neurosci ; 8(8): 1725-34, 1996 Aug.
Article in English | MEDLINE | ID: mdl-8921263

ABSTRACT

In the present study, we show that cultured rat brain macrophages release a soluble factor that stimulates the migration of bone marrow-derived macrophages, as determined by an in vitro chemotaxis assay. A checkerboard analysis indicated that most of this effect resulted from a polarized migration of the cells (chemotactic phenomenon), rather than in an increase in cell motility (chemokinesis). This activity was significantly decreased by an immune serum directed against the rat monocyte chemoattractant protein-1 (chemokine MCP-1). Northern blot analysis demonstrated expression of the MCP-1 gene in cultured brain macrophages, but its absence in unstimulated bone marrow-derived macrophages. Up-regulation of MCP-1 expression was observed when lipopolysaccharide was added to cultured brain macrophages, a peak occurring after a 6 h period of stimulation. Also, inflammatory cytokines such as interleukin (IL)-1 beta, colony stimulating factor-1, tumour necrosis factor-alpha and IL-6 individually increased the basal level of MCP-1 mRNA. Subsequently, we demonstrated the in vivo production of MCP-1 in the adult rat brain following injury induced by a local injection of kainic acid. MCP-1 synthesis was localized in both astrocytes and brain macrophages. These results suggest that the activation of resting microglial cells into brain macrophages and their subsequent secretion of chemokines could contribute to the mechanism(s), leading to the infiltration of the CNS by blood-derived monocytes, as observed in several pathologies.


Subject(s)
Brain/metabolism , Chemokine CCL2/biosynthesis , Microglia/metabolism , Nerve Tissue Proteins/biosynthesis , Animals , Brain/cytology , Brain/drug effects , Cells, Cultured , Culture Media, Conditioned , Cytokines/pharmacology , Lipopolysaccharides/pharmacology , Macrophages/drug effects , Macrophages/metabolism , Male , Microglia/drug effects , Models, Neurological , Rats , Rats, Sprague-Dawley
18.
J Biol Chem ; 271(18): 10709-14, 1996 May 03.
Article in English | MEDLINE | ID: mdl-8631879

ABSTRACT

In this study we have used cultured muscle cells to investigate the role of disulfide bond formation in the sequence of molecular events leading to nicotinic acetylcholine receptor (AChR) assembly and surface expression. We have observed that disulfide bond formation in newly synthesized AChR alpha-subunits occurs 5-20 min after translation and that this modification can be blocked by dithiothreitol (DTT), a membrane-permeant thiol-reducing agent. DTT treatment was found to arrest AChR alpha-subunit conformational maturation, assembly, and appearance on the cell surface, showing that these events are dependent on prior formation of disulfide bonds. Subunits prevented from maturation by the reducing agent do not irreversibly misfold or aggregate, since upon removal of DTT, AChR alpha-subunits undergo formation of disulfide bonds and resume folding, oligomerization, and surface expression. We have previously found that nascent alpha-subunits form transient complexes with the molecular chaperone calnexin immediately after subunit synthesis (Gelman, M.S., Chang, W., Thomas, D. Y., Bergeron, J. J. M., and Prives, J. M. (1995) J. Biol. Chem. 270, 15085-15092) and have now observed that both the formation and the subsequent dissociation of these complexes are unaffected by DTT treatment. Thus, alpha-subunits appear to dissociate from calnexin independently of their undergoing disulfide bond formation and achieving conformational maturation. This finding together with the absence of irreversible misfolding of DTT-arrested alpha-subunits suggests that calnexin may act to prevent misfolding by aiding in the initial folding events and is not an essential participant in the late stages of alpha-subunit maturation.


Subject(s)
Dithiothreitol/pharmacology , Muscles/drug effects , Protein Folding , Receptors, Nicotinic/drug effects , Animals , Calcium-Binding Proteins/metabolism , Calnexin , Cells, Cultured , Chick Embryo , Disulfides/metabolism , Muscles/cytology , Muscles/metabolism , Protein Binding , Protein Conformation , Receptors, Nicotinic/chemistry , Receptors, Nicotinic/metabolism
19.
J Neurosci ; 15(9): 5912-8, 1995 Sep.
Article in English | MEDLINE | ID: mdl-7666176

ABSTRACT

Numerous observations strongly support the hypothesis that dopaminergic neurons could be particularly vulnerable to an impairment of their energetic metabolism. In order to demonstrate the existence of such a selective vulnerability, the toxic effects of rotenone, an inhibitor of complex I of the respiratory chain, and of glutamate, which is very likely involved in the neurotoxicity induced by an energetic stress, were analyzed on cultured mouse mesencephalic neurons. Toxicity toward dopaminergic and GABAergic neurons was compared by measuring the residual uptakes of dopamine and GABA. Exposure to 5 nM rotenone for 6 hr or to a low concentration of glutamate (100 microM) for 1 hr did not lead to a high selective toxic effect on dopaminergic neurons. In contrast, dopaminergic neurons were three times less resistant to the sequential exposure to rotenone and glutamate than GABAergic neurons. A particular resistance of mesencephalic GABAergic neurons to the synergistic toxic effects of rotenone and glutamate was ruled out since two other neuronal types, the striatal cholinergic and GABAergic neurons, displayed the same weak vulnerability as the mesencephalic GABAergic neurons. This selective toxic effect of glutamate on rotenone-pretreated dopaminergic neurons was blocked by either AMPA or NMDA receptor antagonists and mimicked by combined treatment with AMPA and NMDA, or by NMDA alone when the medium was deprived of Mg2+ ions. Moreover, this NMDA-selective neurotoxicity was critically dependent on the presence of a physiological extracellular sodium concentration, since the use of choline chloride instead of sodium chloride had a protective effect on dopaminergic neurons.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Dopamine/physiology , Energy Metabolism , Mesencephalon/physiology , Neurons/physiology , Receptors, N-Methyl-D-Aspartate/physiology , Animals , Cells, Cultured , Corpus Striatum/cytology , Corpus Striatum/drug effects , Corpus Striatum/physiology , Extracellular Space/metabolism , Glutamic Acid/pharmacology , Mesencephalon/cytology , Mesencephalon/drug effects , Mice , Mice, Inbred Strains , Parasympathetic Nervous System/cytology , Parasympathetic Nervous System/drug effects , Receptors, AMPA/physiology , Rotenone/pharmacology , Serotonin/physiology , Sodium/physiology , gamma-Aminobutyric Acid/physiology
20.
J Biol Chem ; 270(25): 15085-92, 1995 Jun 23.
Article in English | MEDLINE | ID: mdl-7797492

ABSTRACT

The nicotinic acetylcholine receptor (AChR) is a pentameric complex assembled from four different gene products by mechanisms that are inadequately understood. In this study we investigated the role of the endoplasmic reticulum (ER)-resident molecular chaperone calnexin in AChR subunit folding and assembly. We have shown that calnexin interacts with nascent AChR alpha-subunits (AChR-alpha) in muscle cell cultures and in COS cells transfected with mouse AChR-alpha. In chick muscle cells maximal association of labeled alpha-subunits with calnexin was observed immediately after a 15-min pulse with [35S]methionine/cysteine and subsequently declined with a t1/2 of approximately 20 min. The decrease in association with calnexin was concomitant with the folding of the alpha-subunit to achieve conformational maturation shortly before assembly. Brefeldin A did not inhibit AChR subunit assembly or the dissociation of calnexin from the assembling subunits, confirming that the ER is the site of AChR assembly and that calnexin dissociation is not affected under conditions in which the exit of assembled AChR from the ER is blocked. These results indicate that calnexin participates directly in the molecular events that lead to AChR assembly.


Subject(s)
Calcium-Binding Proteins/metabolism , Endoplasmic Reticulum/metabolism , Molecular Chaperones/metabolism , Muscle, Skeletal/metabolism , Protein Folding , Receptors, Nicotinic/biosynthesis , Receptors, Nicotinic/chemistry , Animals , Brefeldin A , Calcium-Binding Proteins/isolation & purification , Calnexin , Cells, Cultured , Chick Embryo , Cyclopentanes/pharmacology , Electrophoresis, Polyacrylamide Gel , Kinetics , Macromolecular Substances , Mice , Models, Structural , Molecular Weight , Protein Binding , Protein Synthesis Inhibitors/pharmacology , Receptors, Nicotinic/isolation & purification , Recombinant Proteins/biosynthesis , Recombinant Proteins/chemistry , Recombinant Proteins/isolation & purification , Transfection
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