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1.
Mol Biol Rep ; 47(1): 337-351, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31650383

RESUMO

An imbalance in the redox state, increased levels of lipid precursors and overactivation of de novo lipogenesis determine the development of fibrosis during nonalcoholic steatohepatitis (NASH). We evaluated the modulation of NADPH-producing enzymes associated with the antifibrotic, antioxidant and antilipemic effects of nicotinamide (NAM) in a model of NASH induced by excess fructose consumption. Male rats were provided drinking water containing 40% fructose for 16 weeks. During the last 12 weeks of fructose administration, water containing NAM was provided to some of the rats for 5 h/day. The biochemical profiles and the ghrelin, leptin, lipoperoxidation and TNF-α levels in serum and the glucose-6-phosphate dehydrogenase (G6PD), malic enzyme (ME) and NADP+-dependent isocitric dehydrogenase (IDP) levels, the reduced/oxidized glutathione (GSH/GSSG) and reduced/oxidized nicotinamide adenine dinucleotide (phosphate) (NAD(P)H/NAD(P)+) ratios, and the levels of various lipogenic and fibrotic markers in the liver were evaluated. The results showed that hepatic fibrosis induced by fructose consumption was associated with weight gain, hunger-satiety system dysregulation, hyperinsulinemia, dyslipidemia, lipoperoxidation and inflammation. Moreover, increased levels of hepatic G6PD and ME activity and expression, the NAD(P)H/NAD(P)+ ratios, and GSSG concentration and increased expression of lipogenic and fibrotic markers were detected, and these alterations were attenuated by NAM administration. Specifically, NAM diminished the activity and expression of G6PD and ME, and this effect was associated with a decrease in the NADPH/NADP+ ratios, increased GSH levels and decreased lipoperoxidation and inflammation, ameliorating fibrosis and NASH development. NAM reduces liver steatosis and fibrosis by regulating redox homeostasis through a G6PD- and ME-dependent mechanism.


Assuntos
Fígado Gorduroso/metabolismo , Fígado Gorduroso/prevenção & controle , Niacinamida/farmacologia , Animais , Antioxidantes/metabolismo , Frutose/efeitos adversos , Frutose/metabolismo , Glucose/metabolismo , Glutationa/metabolismo , Homeostase , Metabolismo dos Lipídeos/fisiologia , Lipídeos/biossíntese , Lipogênese/fisiologia , Fígado/metabolismo , Fígado/patologia , Cirrose Hepática/patologia , Masculino , NAD/metabolismo , NADP/metabolismo , Niacinamida/metabolismo , Hepatopatia Gordurosa não Alcoólica/patologia , Oxirredução/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley
2.
Eur J Neurol ; 25(8): 1086-1092, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29660221

RESUMO

BACKGROUND AND PURPOSE: Increased supratentorial white matter hyperintensities volume (S-WMHV) has been reported to be a predictor of worse outcome in patients with acute ischemic stroke (AIS). However, few studies have focused on less common locations, such as brainstem white matter hyperintensities (B-WMH), and their relationship to S-WMHV. This study aimed to examine whether B-WMH affect clinical outcome after AIS or transient ischemic attack (TIA). METHODS: Based on magnetic resonance imaging evidence, B-WMH were evaluated in 313 prospectively identified patients with AIS/TIA and registered as absent or present. Standardized S-WMHV was quantified using a validated volumetric image analysis and natural log-transformed (Log_S-WMHV). Poor outcome was defined as a modified Rankin Scale score of 3-6 at 3 months after the index event. RESULTS: Brainstem white matter hyperintensities were detected in 57 (18.2%) patients. In unadjusted analyses for outcome, the presence of B-WMH was associated with worse outcome, compared with patients without B-WMH (P = 0.034). In multivariate analysis controlling for age, atrial fibrillation, stroke severity, reperfusion therapies and Log_S-WMHV, only B-WMH [odds ratio (OR), 2.46; P = 0.021] and stroke severity (OR, 1.23; P < 0.001) remained independently associated with unfavourable 90-day modified Rankin Scale score. Patients with B-WMH were older (OR, 1.06; P < 0.001) and tended to have more hyperlipidaemia (OR, 2.21; P = 0.023) and peripheral arterial disease (OR, 2.57; P = 0.031). CONCLUSIONS: Brainstem white matter hyperintensities are an independent predictor of poor outcome after AIS/TIA and this relationship persists after adjustment for important prognostic factors. Our results also show that leukoaraiosis in this location identifies patients with a specific risk factor profile, suggesting differences in the underlying pathogenesis.


Assuntos
Isquemia Encefálica/diagnóstico por imagem , Tronco Encefálico/diagnóstico por imagem , Leucoaraiose/diagnóstico por imagem , Acidente Vascular Cerebral/diagnóstico por imagem , Fatores Etários , Idoso , Feminino , Humanos , Hiperlipidemias/complicações , Ataque Isquêmico Transitório/complicações , Ataque Isquêmico Transitório/diagnóstico por imagem , Leucoaraiose/etiologia , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Doença Arterial Periférica/complicações , Valor Preditivo dos Testes , Prognóstico , Estudos Retrospectivos , Resultado do Tratamento , Substância Branca/diagnóstico por imagem
3.
Food Microbiol ; 73: 282-287, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29526213

RESUMO

Simultaneous and individual enumeration of Salmonella, Shigella and Listeria monocytogenes was compared on inoculated Roma tomatoes and Serrano peppers using an Most Probable Number (MPN) technique. Samples consisting of tomatoes (4 units) or peppers (8 units) were individually inoculated with a cocktail of three strains of Salmonella, Shigella or L. monocytogenes, or by simultaneous inoculation of three strains of each pathogen, at low (1.2-1.7 log CFU/sample) and high (2.2-2.7 log CFU/sample) inocula. Samples were analyzed by an MPN technique using universal pre-enrichment (UP) broth at 35 °C for 24 ±â€¯2 h. The UP tubes from each MPN series were transferred to enrichment and plating media following adequate conventional methods for isolating each pathogen. Data were analyzed using multifactorial analysis of variance (p < 0.05) and LSD multiple rang test. There were differences (p < 0.05) in recovery of simultaneous and individual bacteria inoculated (individual > simultaneous), type of bacteria (Salmonella > Shigella and L. monocytogenes), type of sample (UP broth > pepper and tomato), and inoculum level (high > low). The MPN technique was effective for Salmonella on both commodities. Shigella counts were higher on tomatoes compared to peppers, (p < 0.05), and for L. monocytogenes on peppers (p < 0.05).


Assuntos
Capsicum/microbiologia , Listeria monocytogenes/crescimento & desenvolvimento , Salmonella/crescimento & desenvolvimento , Shigella/crescimento & desenvolvimento , Solanum lycopersicum/microbiologia , Contagem de Colônia Microbiana , Contaminação de Alimentos/análise , Frutas/microbiologia , Verduras/microbiologia
4.
Int J Food Microbiol ; 391-393: 110135, 2023 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-36827747

RESUMO

Salmonella enterica genotypic and phenotypic characteristics play an important role in its pathogenesis, which could be influenced by its origin. This study evaluated the association among the antimicrobial resistance, virulence, and origin of circulating S. enterica strains in Mexico, isolated from foods, humans, and the environment. The antimicrobial susceptibility to fourteen antibiotics by the Kirby-Bauer method (n = 117), and the presence of thirteen virulence genes by multiplex PCR (n = 153) and by sequence alignments (n = 2963) were evaluated. In addition, a set of S. enterica isolates from Mexico (n = 344) previously characterized according to their genotypic and phenotypic print was included to increase the coverage of the association analysis. Strains with the presence of sopE and strains with the absence of sspH1 were significantly associated with multidrug-resistant (MDR) phenotypes (p < 0.05). The origin of the strains had significant associations with the antimicrobial profiles and some virulence genes (hilA, orgA, sifA, ssaQ, sseL, sspH1, pefA, and spvC) (p < 0.05). Animal-origin food isolates showed the highest frequency of MDR (57.2 %), followed by human isolates (30.0 %). Also, sspH1, pefA, and spvC were found in major frequency in human (32.4 %, 31.0 %, 31.7 %) and animal-origin foods (41.6 %, 10.6 %, 10.6 %) isolates. The findings highlighted that antimicrobial profiles and specific virulence genes of S. enterica strains are related to their origin. Similar genotypic and phenotypic characteristics between human and animal-origin foods isolates were found, suggesting that animal-origin foods isolates are the most responsible for human cases. The revealed associations can be used to improve risk estimation assessments in national food safety surveillance programs.


Assuntos
Salmonella enterica , Animais , Humanos , Antibacterianos/farmacologia , Virulência/genética , México , Farmacorresistência Bacteriana Múltipla/genética , Farmacorresistência Bacteriana , Testes de Sensibilidade Microbiana
5.
Rev Esp Quimioter ; 35(6): 538-543, 2022 Dec.
Artigo em Espanhol | MEDLINE | ID: mdl-36164855

RESUMO

OBJECTIVE: Serological tests have been a valuable tool during the SARS-CoV-2 pandemic, supporting molecular methods for detection, and monitoring the immune response, caused by vaccination or by natural infection. Within all these techniques, rapid tests are interesting due to their ease of use, rapid response and low cost. METHODS: Two different immunological techniques were evaluated: Realy Tech and Mikrogen Diagnostik recomLine SARS-CoV-2 IgG. SARS-CoV-2 IgG II Quant antibody test and SARS-CoV-IgG assay, both from Abbott Diagnostics, were used as reference techniques. RESULTS: Mikrogen Diagnostik recomLine SARS-CoV-2 IgG shows the best results (S=0.985; E=0.839). Three techniques offered good positive predictive values, but Realy Tech and Healgen negative predictive values left to be desired. CONCLUSIONS: Mikrogen Diagnostik recomLine SARS-CoV-2 IgG showed good results in the detection of antibodies against SARS-CoV-2 and could be used as an alternative to automated techniques.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , Teste para COVID-19 , COVID-19/diagnóstico , Sensibilidade e Especificidade , Anticorpos Antivirais , Imunoglobulina G
6.
Rev Esp Quimioter ; 32 Suppl 2: 1-9, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31475801

RESUMO

The IX Course of Antimicrobials and Infectious Diseases update included a review of the main issues in clinical microbiology, epidemiology and clinical aspects for a current approach of infectious pathology. The present introduction summarizes about the most important meetings related to infectious diseases during 2018 (ECCMID, IAS, ASM and ID Week). In addition, the course provides a practical information to focus on nosocomial infection models, with immunosuppressed patients or complex multidrug-resistant pathogens. The closing lecture of this year reviewed the infection during donation process.


Assuntos
Infecções , Infectologia/tendências , Anti-Infecciosos/farmacologia , Anti-Infecciosos/uso terapêutico , Doenças Transmissíveis , Infecção Hospitalar/tratamento farmacológico , Infecção Hospitalar/prevenção & controle , Humanos , Hospedeiro Imunocomprometido
7.
J Food Sci ; 83(2): 419-423, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29337351

RESUMO

The high concentration of fructose in agave juice has been associated with reduced ethanol tolerance of commercial yeasts used for tequila production and low fermentation yields. The selection of autochthonous strains, which are better adapted to agave juice, could improve the process. In this study, a 2-step selection process of yeasts isolated from spontaneous fermentations for tequila production was carried out based on analysis of the growth dynamics in combined conditions of high fructose and ethanol. First, yeast isolates (605) were screened to identify strains tolerant to high fructose (20%) and to ethanol (10%), yielding 89 isolates able to grow in both conditions. From the 89 isolates, the growth curves under 8 treatments of combined fructose (from 20% to 5%) and ethanol (from 0% to 10%) were obtained, and the kinetic parameters were analyzed with principal component analysis and k-means clustering. The resulting yeast strain groups corresponded to the fast, medium and slow growers. A second clustering of only the fast growers led to the selection of 3 Saccharomyces strains (199, 230, 231) that were able to grow rapidly in 4 out of the 8 conditions evaluated. This methodology differentiated strains phenotypically and could be further used for strain selection in other processes. PRACTICAL APPLICATION: A method to select yeast strains for fermentation taking into account the natural differences of yeast isolates. This methodology is based on the cell exposition to combinations of sugar and ethanol, which are the most important stress factors in fermentation. This strategy will help to identify the most tolerant strain that could improve ethanol yield and reduce fermentation time.


Assuntos
Agave , Bebidas Alcoólicas/microbiologia , Etanol , Fermentação , Frutose , Saccharomyces cerevisiae/crescimento & desenvolvimento , Carboidratos , Meios de Cultura , Saccharomyces cerevisiae/isolamento & purificação , Saccharomyces cerevisiae/metabolismo
9.
Clin Transl Oncol ; 19(6): 727-734, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28005261

RESUMO

PURPOSE: We assessed agreement among neurosurgeons on surgical approaches to individual glioblastoma patients and between their approach and those recommended by the topographical staging system described by Shinoda. METHODS: Five neurosurgeons were provided with pre-surgical MRIs of 76 patients. They selected the surgical approach [biopsy, partial resection, or gross total resection (GTR)] that they would recommend for each patient. They were blinded to each other's response and they were told that patients were younger than 50 years old and without symptoms. Three neuroradiologists classified each case according to the Shinoda staging system. RESULTS: Biopsy was recommended in 35.5-82.9%, partial resection in 6.6-32.9%, and GTR in 3.9-31.6% of cases. Agreement among their responses was fair (global kappa = 0.28). Nineteen patients were classified as stage I, 14 as stage II, and 43 as stage III. Agreement between the neurosurgeons and the recommendations of the staging system was poor for stage I (kappa = 0.14) and stage II (kappa = 0.02) and fair for stage III patients (kappa = 0.29). An individual analysis revealed that in contrast to the Shinoda system, neurosurgeons took into account T2/FLAIR sequences and gave greater weight to the involvement of eloquent areas. CONCLUSIONS: The surgical approach to glioblastoma is highly variable. A staging system could be used to examine the impact of extent of resection, monitor post-operative complications, and stratify patients in clinical trials. Our findings suggest that the Shinoda staging system could be improved by including T2/FLAIR sequences and a more adequate weighting of eloquent areas.


Assuntos
Neoplasias Encefálicas/cirurgia , Glioblastoma/cirurgia , Estadiamento de Neoplasias/métodos , Procedimentos Neurocirúrgicos/normas , Adulto , Neoplasias Encefálicas/patologia , Ensaios Clínicos Fase II como Assunto , Glioblastoma/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Neurocirurgiões/normas , Procedimentos Neurocirúrgicos/métodos , Ensaios Clínicos Controlados Aleatórios como Assunto , Inquéritos e Questionários
10.
Biochim Biophys Acta ; 1030(2): 195-202, 1990 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-2175652

RESUMO

Ca2(+)-ATPase activity was measured in electric organ synaptosomal homogenates and their derived presynaptic plasma membranes using a low ionic strength medium, low in Ca2+ and Mg2+, and devoid of K+. The enzyme activity showed a high apparent affinity for Ca2+ (KCa:0.5 microM) and was: (1) 5-fold stimulated by 120 nM calmodulin, (2) highly sensitive to LaCl3 inhibition, and (3) not affected by 20 mM NaN3 or 0.1 mM ouabain. The addition of Mg2+ promoted the disappearance of Ca2(+)-ATPase activity. Incubation of synaptosomal homogenates in the above-mentioned assay medium with [gamma -32P]ATP resulted in the appearance of a 140 kDa band as revealed by SDS-gel electrophoresis. Labeling of this band with 32P was inhibited by 1 mM EGTA or 10 mM NH2OH, indicating that the isotope incorporation required the presence of Ca2+ and the formation of an acyl-phosphate derivative. The results indicate that the Ca2(+)-ATPase activity from synaptosomal homogenates had characteristics corresponding to those of the enzyme that catalyzes an outward transport of Ca2+ in nerve terminals. Preincubation of synaptosomes in Ca2+ plus K+, a depolarizing procedure, induced a large and rapid decrease in the Ca2(+)-ATPase activity, possibly mediated via Ca2+ entry through voltage-gated Ca2+ channels. Furthermore, the muscarinic cholinergic agonist oxotremorine (at 15 microM concentration) did not significantly affect either the enzyme activity or the intensity of the Ca2(+)-dependent 32P incorporation into the 140 kDa band, suggesting that the enzyme is not coupled to muscarinic binding sites.


Assuntos
ATPases Transportadoras de Cálcio/metabolismo , Órgão Elétrico/enzimologia , Oxotremorina/farmacologia , Membranas Sinápticas/enzimologia , Animais , Sítios de Ligação , Cálcio/farmacologia , Canais de Cálcio/efeitos dos fármacos , Canais de Cálcio/metabolismo , Ácido Egtázico/farmacologia , Peixe Elétrico , Magnésio/farmacologia , Masculino , Radioisótopos de Fósforo , Membranas Sinápticas/efeitos dos fármacos , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/enzimologia
11.
Rev Esp Med Nucl Imagen Mol ; 34(6): 350-7, 2015.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-26118354

RESUMO

AIMS: Brain perfusion SPECT (ictal-interictal), SPECT images and subtraction ictal SPECT coregistered to MRI (SISCOM) and (18)F-FDG-PET (interictal), play an important role in the pre-surgical diagnosis of patients with medically refractory epilepsy. This study aimed to establish: the reproducibility of visual ictal-interictal SPECT and SISCOM analysis altogether with the capacity of SPECT, SISCOM and PET to determine the epileptogenic zone. MATERIAL AND METHODS: (99m)Tc-HMPAO SPECT ictal-interictal and SISCOM (Analyze 7.0) were performed on 47 refractory epilepsy patients (24 F, 19-60 yrs). In 13 patients, SISCOM was also performed using a new program (Focus DET). Ictal-interictal SPECT and SISCOM images were analysed independently by two nuclear medicine physicians (observer 1 and 2). Kappa concordance coefficient was used to evaluate the reproducibility. In sixteen patients, SPECT, SISCOM and PET findings were compared with the resected area during the surgery, and surgical outcome using Engel scale or with the stereo EEG-(SEEG). RESULTS: The ictal-interictal SPECT interobserver agreement was 91%, Kappa index 0.86, SISCOM (Analyze 7.0) interobserver agreement percentage was 82%, Kappa index 0.80, Analyze 7.0 showed a higher inconclusive results than visual SPECT analysis. SISCOM FocusDET interobserver agreement was 92%, Kappa index 0.87, with lower inconclusive results than Analyze 7.0. SPECT, SISCOM and PET combined findings identified 87% seizure onset zone: 79% temporal, 26% parieto-temporal and 7% frontal. CONCLUSIONS: Ictal-interictal SPECT and SISCOM showed a high reproducibility in this sample of patients with drug-refractory epilepsy. SPECT,SISCOM and PET combined findings improved detection of epileptogenic zone in comparison with the individual assessment.


Assuntos
Epilepsia Resistente a Medicamentos/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Imagem Multimodal/métodos , Neuroimagem/métodos , Imagem de Perfusão/métodos , Tomografia por Emissão de Pósitrons/métodos , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Adulto , Anticonvulsivantes/uso terapêutico , Circulação Cerebrovascular , Resistência a Medicamentos , Epilepsia Resistente a Medicamentos/tratamento farmacológico , Epilepsia Resistente a Medicamentos/cirurgia , Eletroencefalografia/métodos , Feminino , Radioisótopos de Flúor , Fluordesoxiglucose F18 , Humanos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Compostos Radiofarmacêuticos , Reprodutibilidade dos Testes , Estudos Retrospectivos , Técnica de Subtração , Tecnécio Tc 99m Exametazima
12.
J Food Prot ; 78(12): 2170-6, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26613911

RESUMO

Some Leuconostoc spp. have the ability to produce slime and undesirable compounds in cooked sausage. The objectives of this research were to identify Leuconostoc sources in a Vienna-type sausage processing plant and to evaluate the genetic diversity of the isolated strains. Three hundred and two samples of sausage batter, sausages during processing, spoiled sausage, equipment surfaces, chilling brine, workers' gloves and aprons, and used casings were collected (March to November 2008 and February to April 2010) from a sausage processing plant. Lactic acid bacteria (LAB) were quantified, and Leuconostoc were detected using PCR. Strains were isolated and identified in Leuconostoc-positive samples. Leuconostoc strains were genotyped using randomly amplified polymorphic DNA and pulsed-field gel electrophoresis. LAB content of nonspoiled and spoiled sausage ranged from <0.8 to 4.4 log CFU/g and from 4.9 to 8.3 log CFU/g, respectively. LAB levels on equipment surfaces ranged from <1.3 to 4.8 log CFU/100 cm(2). Leuconostoc was detected in 35% of the samples, and 88 Leuconostoc spp. strains were isolated and genotyped. The main Leuconostoc spp. isolated were L. mesenteroides (37 genotypes), L. fallax (29 genotypes), and L. lactis (6 genotypes). Some strains of Leuconostoc isolated from equipment surfaces and sausages showed the same genotype. One L. lactis genotype included strains isolated from spoiled sausages analyzed in April 2008 and March to April 2010. Equipment and conveyor belts constitute Leuconostoc contamination sources. Leuconostoc persistence in the sausage processing environment and in the final product suggests the existence of microbial reservoirs, possibly on equipment surfaces.


Assuntos
Leuconostoc/isolamento & purificação , Produtos da Carne/microbiologia , Animais , Contagem de Colônia Microbiana , Manipulação de Alimentos/instrumentação , Genótipo , Leuconostoc/genética , Leuconostoc/crescimento & desenvolvimento , Suínos
13.
J Comp Neurol ; 430(1): 56-71, 2001 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-11135245

RESUMO

Messenger RNA (mRNA) targeting to specific subcellular domains has been studied extensively in many cell types, and there is increasing evidence suggesting that mRNA sorting also occurs in astrocytes. As a step toward developing strategies to evaluate the signals that govern mRNA sorting in astrocytes, the authors studied the subcellular distribution of several representative mRNAs, poly(A) RNA and ribosomal RNA, in process-bearing (type-2) astroglial cells in culture. Nonradioactive in situ hybridization analysis revealed a gradual increase in the expression of glial fibrillary acidic protein (GFAP) mRNA as type-2 astrocytes differentiated in culture. In mature cells, labeling was present in both cell bodies and processes. GFAP mRNA labeling was granular in nature and was particularly concentrated at branch points and at the tips of the processes. Unlike GFAP mRNA, vimentin, beta-tubulin, and beta- and gamma-actin mRNAs were mainly confined to the cell bodies, with only occasional labeling seen in the processes. Nonradioactive and radioactive in situ hybridization analysis of poly(A) and ribosomal RNA, respectively, revealed labeling in cell bodies and processes of immature and differentiated astrocytes. Treatment with nocodazole, a microtubule depolymerizing agent, resulted in a substantial reduction of GFAP mRNA labeling in the processes, whereas treatment with cytochalasin D, a microfilament-disrupting agent, did not alter GFAP mRNA distribution. The results indicate that cultured type-2 astrocytes have the capacity to sort mRNAs to different subcellular domains and that the localization of GFAP mRNA to astrocyte processes requires intact microtubules.


Assuntos
Astrócitos/metabolismo , RNA Mensageiro/metabolismo , Actinas/genética , Animais , Células Cultivadas , Citoesqueleto/metabolismo , Proteína Glial Fibrilar Ácida/genética , Poli A/genética , RNA Ribossômico/metabolismo , Ratos , Ratos Sprague-Dawley , Distribuição Tecidual , Tubulina (Proteína)/genética , Vimentina/genética
14.
Neurochem Int ; 11(2): 175-81, 1987.
Artigo em Inglês | MEDLINE | ID: mdl-20501159

RESUMO

The antiviral drug amantadine is also a potent neuromuscular blocking agent. When the nicotinic receptor from a Torpedinidae species is reconstituted into soybean liposomes, the binding of ?-bungarotoxin is not altered although the carbamylcholine induced radioactive cation influx is blocked. By studying cation fluxes in amantadine preincubated membranes previously exposed to different concentrations of carbamylcholine for different periods of time, we have shown that the drug accelerates the conversion of the nicotinic acetylcholine receptor from a state of low affinity to a state of high affinity for carbamyalcholine, a phenomenon correlated with receptor desensitization. The drug did not induce such a shift by itself. The present data and those by Earnest et al. (Biochemistry22, 5523-5535, 1984) show that the nicotinic acetylcholine receptor reconstituted into liposomes is a good model for studying the effects of noncompetitive blockers of nicotinic acetylcholine receptor function.

15.
Neurochem Int ; 14(1): 65-72, 1989.
Artigo em Inglês | MEDLINE | ID: mdl-20504401

RESUMO

The poly (ethylene) glycol 6000 (PEG) precipitation procedure was applied for incorporating the nicotinic acetylcholine receptor from D. tschudii electric organ into Asolectin liposomes. The incorporated receptor had its toxin binding sites oriented towards the external bulk phase and bound [(125)I]?-bungarotoxin with the same rate of toxin binding and cholinergic agonist equilibrium low affinity constant as its membrane bound counterpart. A characteristic feature of those vesicles, however, was the absence of the affinity transitions which normally correlate with the receptor densensitization phenomenon, and a poor carbamylcholine-stimulated ion flux as compared to that exhibited by vesicles prepared by the cholate dialysis procedure. When ether-purified PEG was used, the incorporated receptor showed affinity transitions and carbamylcholine-induced cation influx into vesicles. Thin layer chromatography and quantitative densitometry analysis showed that the vesicles prepared by the PEG precipitation method contained higher amounts of free fatty acids than those prepared by the cholate-dialysis procedure. Results are interpreted as an impairment of receptor function by impurities contained in commercial preparations of PEG and/or free fatty acids possibly generated by PEG impurities from Asolectin lipids. The proposed mechanisms are modifications in vesicle geometry and perturbations in lipid-protein interactions known to be essential for normal nicotinic receptor operation. The PEG precipitation procedure has the potential for rapid reconstitution of the nicotinic receptor and other membrane proteins that cannot be solubilized by easily dialyzable detergents provided purified PEG is used.

16.
Brain Res ; 592(1-2): 202-7, 1992 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-1450911

RESUMO

Astrocytes from a variety of sources, including the human UC-11MG astrocytoma line, express receptors for histamine on their plasma membranes, but the function of these receptors is largely unknown. Here we report studies on the effect of histamine on newly synthesized glycogen in the human astrocytoma-derived cell line, UC-11MG. We have found [3H]glycogen hydrolysis with a EC50 of 2 microM and a maximum effect of 30% at 300 microM histamine. The glycogenolytic effect of histamine was completely blocked by the H1 receptor antagonist, mepyramine, and was insensitive to the H2 receptor antagonist, cimetidine. Histamine-induced glycogenolysis was significantly reduced in the absence of extracellular Ca2+ and the residual response could be accounted for by Ca2+ released from intracellular stores. The Ca2+ ionophore, ionomycin, induced a similar concentration-dependent increase in both intracellular Ca2+ concentration and in glycogenolysis. These results suggest that one function of astrocytic histamine receptors in vivo may be the stimulation of glucose release from astrocytes, and that this process is mediated by increased intracellular free Ca2+. The glycogenolytic effect of histamine and other neurotransmitters in different systems, and the possible implication of astrocytic glycogenolysis in the pathophysiology of ischemia are discussed.


Assuntos
Astrocitoma/metabolismo , Cálcio/metabolismo , Glicogênio/metabolismo , Histamina/farmacologia , Astrocitoma/patologia , Cálcio/fisiologia , Relação Dose-Resposta a Droga , Ácido Egtázico/farmacologia , Glucose/metabolismo , Antagonistas dos Receptores Histamínicos , Humanos , Membranas Intracelulares/metabolismo , Ionomicina/farmacologia , Receptores Histamínicos/classificação , Receptores Histamínicos/fisiologia , Células Tumorais Cultivadas
17.
Brain Res ; 523(1): 69-77, 1990 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-2207691

RESUMO

The swelling of astrocytes is an important component of the morbidity and mortality associated with ischemic brain trauma. In the ischemic brain, lactic acid levels rise dramatically with a concomitant acidification of the extracellular fluid. In this study we have measured the effects of elevated extracellular lactate and reduced extracellular pH (pHo) on astrocyte volume using the human astrocyte-derived cell line UC-11MG. Neither elevated lactate nor reduced pHo alone increased cell volume, but swelling of about 25% was measured when the cells were exposed simultaneously to 20 mM lactic acid and a reduced pHo of 6. The swelling was correlated with an approximately 4-fold increase in intracellular lactate as pHo was decreased from 8.0 to 6.0. As pHo was decreased intracellular pH also decreased, but much more slowly so that at acidic extracellular pH there was an inwardly directed proton gradient. The measured intracellular lactate concentrations closely followed the theoretical levels predicted by a model in which lactate transport is coupled to the inwardly directed proton gradient. Kinetic studies indicated that lactate transport is saturable with a Km of 3.8 mM, consistent with the model for facilitated cotransport of lactate with a proton or exchange of lactate for a hydroxyl ion. These data suggest that an important mechanism of postischemic astrocytic swelling is a proton driven, active accumulation of lactate to levels that result in a significant osmotic gradient of lactate at acidic pH.


Assuntos
Astrócitos/fisiologia , Membrana Celular/fisiologia , Lactatos/farmacologia , Alanina/metabolismo , Astrócitos/efeitos dos fármacos , Neoplasias Encefálicas/ultraestrutura , Membrana Celular/efeitos dos fármacos , Dimetadiona/farmacologia , Glioma/ultraestrutura , Humanos , Concentração de Íons de Hidrogênio , Ácido Láctico , Potenciais da Membrana/efeitos dos fármacos , Espectrometria de Fluorescência , Células Tumorais Cultivadas/ultraestrutura
18.
Neurosci Lett ; 167(1-2): 14-8, 1994 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-7513838

RESUMO

In this study we report that substance P stimulated [3H]glycogen breakdown and elevation of intracellular Ca2+ concentration in the human astrocytoma cell line UC-11MG. Both effects were dose dependent, and completely blocked by CP-96,345 suggesting the involvement of an NK1 receptor. Our previous studies indicated that norepinephrine and histamine stimulate glycogenolysis via cAMP and Ca2+ respectively. Combined stimulation with substance P and norepinephrine or histamine resulted in additive effects suggesting that there is no interaction between these neurotransmitters in regulating glycogenolysis in these cells. These results confirm that UC-11MG cells are a useful model system to investigate the functional role of neurotransmitter receptors in astroglial cells.


Assuntos
Astrocitoma/metabolismo , Neoplasias Encefálicas/metabolismo , Glicogênio/metabolismo , Receptores da Neurocinina-1/metabolismo , Astrocitoma/patologia , Compostos de Bifenilo/farmacologia , Neoplasias Encefálicas/patologia , Relação Dose-Resposta a Droga , Combinação de Medicamentos , Histamina/farmacologia , Humanos , Norepinefrina/farmacologia , Substância P/farmacologia , Células Tumorais Cultivadas
19.
AJNR Am J Neuroradiol ; 34(6): 1188-93, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23306014

RESUMO

BACKGROUND AND PURPOSE: Whereas fMRI postprocessing tools used in research are accurate but unwieldy, those used for clinical practice are user-friendly but are less accurate. We aimed to determine whether commercial software for fMRI postprocessing is accurate enough for clinical practice. METHODS: Ten volunteers underwent fMRI while performing motor and language tasks (hand, foot, and orolingual movements; verbal fluency; semantic judgment; and oral comprehension). We compared visual concordance, image quality (noise), voxel size, and radiologist preference for the activation maps obtained by using Neuro3D software (provided with our MR imaging scanner) and by using the SPM program commonly used in research. RESULTS: Maps obtained with the 2 methods were classified as "partially overlapping" for 70% for motor and 72% for language paradigm experiments and as "overlapping" in 30% of motor and in 15% of language paradigm experiments. CONCLUSIONS: fMRI is a helpful and robust tool in clinical practice for planning neurosurgery. Widely available commercial fMRI software can provide reliable information for therapeutic management, so sophisticated, less widely available software is unnecessary in most cases.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Desempenho Psicomotor , Software , Feminino , Humanos , Masculino
20.
J Food Prot ; 74(12): 2177-81, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22186061

RESUMO

Two cases of acute gastroenteritis occurred in 5-month-old infants hospitalized in a mother-and-child hospital in Queretaro, Mexico, on 24 January 2010. C. sakazakii was recovered from the powdered infant formula (PIF), rehydrated PIF (R-PIF) fed to infants, and their fecal samples. The microorganism was present at levels of 0.33 most probable number (MPN)/g and 24 MPN/ml in PIF and R-PIF, respectively. The total ingested dose for the day before the onset of the diarrheic syndrome ranged between 2,160 and 3,600 MPN/ml. All strains of C. sakazakii recovered from the three sources (R-PIF, PIF, and fecal matter) showed identical biotypes, adhesion and invasiveness factors, and pulsed-field gel electrophoresis profiles. No deaths were observed. Salmonella, Shigella, and enterotoxigenic Escherichia coli were not found in food or fecal samples.


Assuntos
Cronobacter sakazakii/isolamento & purificação , Infecções por Enterobacteriaceae/epidemiologia , Contaminação de Alimentos/análise , Gastroenterite/epidemiologia , Alimentos Infantis/microbiologia , Fórmulas Infantis , Cronobacter sakazakii/crescimento & desenvolvimento , Fezes/microbiologia , Feminino , Hospitalização , Humanos , Lactente , Masculino
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