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1.
BMC Med Educ ; 22(1): 723, 2022 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-36242009

RESUMEN

BACKGROUND: Introducing radiological anatomy in the preclinical curriculum can increase the understanding of Anatomy. Regardless of the integration when teaching anatomy, it is essential to maintain oversight as to what and how much is being taught. In addition, the knowledge requirements for preclinical students should be considered. The purpose of this kind of integration is that the student should be able to apply the knowledge which can help them better understand anatomy and not to make the course more challenging. This study aimed to understand whether adding radiological images would increase the difficulty level of the questions. METHODS: We introduced radiological images, including X Rays, CT scans and MRIs, when teaching anatomy in the preclinical curriculum. A class of 99 students were tested using A-type MCQs (n = 84). All 84 questions were categorized on whether they were case-based with or without a radiological image. The item analysis of both groups of test questions was then compared based on their difficulty and discrimination index. A qualitative student perception regarding the inclusion of radiological images in anatomy was also measured using a questionnaire with a 5-point Likert scale. RESULTS: The results showed that the performance level of the students was similar when comparing the test questions in both groups. The item analysis of the MCQs in the two groups revealed that by integrating radiological images when teaching anatomy, the various parameters in both groups of test questions were in the same range. More than 80% of the students felt that radiological images facilitate the achievement of learning outcomes and help to apply their knowledge in clinical contexts. The study's findings reported that the rate of satisfaction by including radiological images when teaching anatomy is high. CONCLUSION: Recognition and interpretation of images are essential in an undergraduate medical program. Students found it helpful when radiological images were introduced to them when teaching anatomy. Since the students' performance in summative exams in both groups of questions was in the same range, the findings also point out that adding radiological images when teaching anatomy does not increase the difficulty of the subject.


Asunto(s)
Anatomía , Educación de Pregrado en Medicina , Radiología , Estudiantes de Medicina , Anatomía/educación , Curriculum , Educación de Pregrado en Medicina/métodos , Evaluación Educacional , Humanos , Aprendizaje , Radiología/educación , Encuestas y Cuestionarios , Enseñanza
2.
Eur J Neurol ; 27(2): 308-317, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-31465603

RESUMEN

BACKGROUND AND PURPOSE: The goal of this study was to determine the prevalence and incidence of neuromyelitis optica spectrum disorder (NMOSD) in Hungary based on the 2015 International Panel of NMO Diagnosis (IPND) criteria. METHODS: A retrospective population-based cohort study was conducted of 6.4 million Hungarians (age ≥ 16 years) between 1 January 2006 and 31 December 2016. Possible NMOSD patients were selected via multistage re-evaluation from multiple sources. Crude and sex- and serostatus-specific prevalence (per 100 000 persons) and incidence rates (per 1 000 000 person-years) from 2006 to 2015 were estimated and age-adjusted rates were determined. RESULTS: Of 2262 study candidates, 154 NMOSD patients (age ≥ 16 years) with onset until 31 December 2016 were identified based on 2015 IPND criteria. The prevalence analysis on 1 January 2016 included 123 NMOSD living cases, resulting in a prevalence of 1.91 [95% confidence interval (CI) 1.52-2.28] per 100 000 persons. The 101 incident cases emerging from the observed 76 394 288 person-years provided an incidence rate of 1.32 (95% CI 1.08-1.61) per 1 000 000 person-years. Age-adjusted prevalence was 1.87 (95% CI 1.56-2.23) per 100 000 persons and incidence was 1.20 (95% CI 0.98-1.46) per 1 000 000 person-years. CONCLUSIONS: In this first report of a large population-based epidemiological study from an Eastern European Caucasian population using robust case validation, a greater prevalence and incidence of NMOSD was found compared to previous large studies in Caucasian populations.


Asunto(s)
Neuromielitis Óptica , Adolescente , Acuaporina 4 , Estudios de Cohortes , Humanos , Hungría/epidemiología , Incidencia , Neuromielitis Óptica/epidemiología , Estudios Retrospectivos
3.
Lett Appl Microbiol ; 69(4): 271-278, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31385615

RESUMEN

Antifungal lock therapy has received significant interest in the last few years because the frequently usage of intravascular devices is associated with an increasing number of catheter-related bloodstream infections caused by Candida species. Antifungal combinations with synergistic interaction can be a good choice for antifungal lock therapy; therefore, interactions were examined between two echinocandins (caspofungin and micafungin) and the chitin synthesis inhibitor nikkomycin Z against Candida albicans and C. parapsilosis biofilms. Susceptibility was evaluated using the XTT-based checkerboard microdilution method, while the nature of interactions was assessed by calculating fractional inhibitory concentration indices and using the Bliss independence model. Mathematic-based evaluations were supplemented with fluorescent LIVE/DEAD viability assay. The results obtained by statistical interaction analyses correlated well with the viability assay. The tested echinocandins with nikkomycin Z caused an extended cell death and the structure of the biofilm was sparse compared to the control, especially for C. albicans. The findings support the simultaneous usage of nikkomycin Z and caspofungin or micafungin in alternative therapies such as the antifungal lock therapy. SIGNIFICANCE AND IMPACT OF THE STUDY: Antifungal lock therapy can be a potential therapeutic approach to eradicate the intraluminal Candida biofilms; however, there is no approved lock strategy against fungal species so far. The results of this study provide valuable evidence that nikkomycin Z acts synergistically in combination with caspofungin or micafungin against biofilms. In addition, this synergy was more pronounced for micafungin combined with nikkomycin Z. Therefore, nikkomycin Z can be considered as a potential agent in antifungal lock therapy especially with micafungin against C. albicans or C. parapsilosis biofilms.


Asunto(s)
Aminoglicósidos/farmacología , Antifúngicos/farmacología , Biopelículas/crecimiento & desarrollo , Candida albicans/efectos de los fármacos , Candida parapsilosis/efectos de los fármacos , Caspofungina/farmacología , Micafungina/farmacología , Infecciones Relacionadas con Catéteres/tratamiento farmacológico , Infecciones Relacionadas con Catéteres/microbiología , Infecciones Relacionadas con Catéteres/prevención & control , Sinergismo Farmacológico , Humanos , Pruebas de Sensibilidad Microbiana
4.
J Appl Microbiol ; 122(6): 1529-1536, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28321957

RESUMEN

AIMS: Fungal quorum-sensing molecules may have an inhibitory effect as adjuvant against Candida biofilms. Therefore, in vitro activity of caspofungin and micafungin was evaluated against Candida parapsilosis biofilms in the presence of tyrosol. METHODS AND RESULTS: Interactions were assessed using fractional inhibitory concentration index (FICI) determination, metabolic activity-based time-kill experiments and scanning electron microscopy (SEM). Tyrosol caused 1-16-fold and 2-32-fold decrease in median caspofungin and micafungin MICs respectively. Based on FICI, synergy was observed in isolates 27001 and 17820 with caspofungin and 27001 with micafungin. In time-kill experiments, the metabolic activity reduction was higher for micafungin compared to caspofungin at 24 h especially when used in 64 and 256 mg l-1 concentrations. In the case of micafungin, the 256 mg l-1  + 1 mmol l-1 combination caused significantly higher decrease in metabolic activity compared to the corresponding concentration alone (256 mg l-1 ) at 24 h (P < 0·05). SEM confirmed the higher killing effect of tested echinocandins with tyrosol. CONCLUSIONS: Considerable metabolic activity reduction and cell damage was detected for combinations especially in the case of micafungin. SIGNIFICANCE AND IMPACT OF THE STUDY: Our findings support the development of new alternative therapeutic strategies against C. parapsilosis biofilms.


Asunto(s)
Antifúngicos/farmacología , Candida/efectos de los fármacos , Equinocandinas/farmacología , Lipopéptidos/farmacología , Alcohol Feniletílico/análogos & derivados , Biopelículas/efectos de los fármacos , Candida/aislamiento & purificación , Candida/fisiología , Caspofungina , Humanos , Micafungina , Pruebas de Sensibilidad Microbiana , Alcohol Feniletílico/farmacología
5.
Pflugers Arch ; 467(6): 1277-90, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25015415

RESUMEN

Bile acids play important physiological role in the solubilisation and absorption of dietary lipids. However, under pathophysiological conditions, such as short bowel syndrome, they can reach the colon in high concentrations inducing diarrhoea. In this study, our aim was to characterise the cellular pathomechanism of bile-induced diarrhoea using human samples. Colonic crypts were isolated from biopsies of patients (controls with negative colonoscopic findings) and of cholecystectomised/ileum-resected patients with or without diarrhoea. In vitro measurement of the transporter activities revealed impaired Na⁺/H⁺ exchanger (NHE) and Cl⁻/HCO3⁻ exchanger (CBE) activities in cholecystectomised/ileum-resected patients suffering from diarrhoea, compared to control patients. Acute treatment of colonic crypts with 0.3 mM chenodeoxycholate caused dose-dependent intracellular acidosis; moreover, the activities of acid/base transporters (NHE and CBE) were strongly impaired. This concentration of chenodeoxycholate did not cause morphological changes in colonic epithelial cells, although significantly reduced the intracellular ATP level, decreased mitochondrial transmembrane potential and caused sustained intracellular Ca²âº elevation. We also showed that chenodeoxycholate induced Ca²âº release from the endoplasmic reticulum and extracellular Ca²âº influx contributing to the Ca²âº elevation. Importantly, our results suggest that the chenodeoxycholate-induced inhibition of NHE activities was ATP-dependent, whereas the inhibition of CBE activity was mediated by the sustained Ca²âº elevation. We suggest that bile acids inhibit the function of ion transporters via cellular energy breakdown and Ca²âº overload in human colonic epithelial cells, which can reduce fluid and electrolyte absorption in the colon and promote the development of diarrhea.


Asunto(s)
Señalización del Calcio , Ácido Quenodesoxicólico/farmacología , Antiportadores de Cloruro-Bicarbonato/metabolismo , Fármacos Gastrointestinales/farmacología , Mucosa Intestinal/metabolismo , Potencial de la Membrana Mitocondrial , Intercambiadores de Sodio-Hidrógeno/metabolismo , Adenosina Trifosfato/metabolismo , Adulto , Células Cultivadas , Colon/metabolismo , Humanos , Íleon/metabolismo , Mucosa Intestinal/efectos de los fármacos , Persona de Mediana Edad
6.
Eur J Hybrid Imaging ; 5(1): 3, 2021 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-34181137

RESUMEN

BACKGROUND: Metabolic syndrome and its individual components lead to wide-ranging consequences, many of which affect the central nervous system. In this study, we compared the [18F]FDG regional brain metabolic pattern of participants with type 2 diabetes mellitus (T2DM) and non-DM obese individuals. METHODS: In our prospective study, 51 patients with controlled T2DM (ages 50.6 ± 8.0 years) and 45 non-DM obese participants (ages 52.0 ± 9.6 years) were enrolled. Glucose levels measured before PET/CT examination (pre-PET glucose) as well as laboratory parameters assessing glucose and lipid status were determined. NeuroQ application (NeuroQTM 3.6, Syntermed, Philips) was used to evaluate regional brain metabolic differences. [18F]FDG PET/CT (AnyScan PC, Mediso) scans, estimating brain metabolism, were transformed to MNI152 brain map after T1 registration and used for SPM-based group comparison of brain metabolism corrected for pre-PET glucose, and correlation analysis with laboratory parameters. RESULTS: NeuroQ analysis did not reveal significant regional metabolic defects in either group. Voxel-based group comparison revealed significantly (PFWE<0.05) decreased metabolism in the region of the precuneus and in the right superior frontal gyrus (rSFG) in the diabetic group as compared to the obese patients. Data analysis corrected for pre-PET glucose level showed a hypometabolic difference only in the rSFG in T2DM. Voxel-based correlation analysis showed significant negative correlation of the metabolism in the following brain regions with pre-PET glucose in diabetes: precuneus, left posterior orbital gyrus, right calcarine cortex and right orbital part of inferior frontal gyrus; whilst in the obese group only the right rolandic (pericentral) operculum proved to be sensitive to pre-PET glucose level. CONCLUSIONS: To our knowledge, this is the first study to perform pre-PET glucose level corrected comparative analysis of brain metabolism in T2DM and obesity. We also examined the pre-PET glucose level dependency of regional cerebral metabolism in the two groups separately. Large-scale future studies are warranted to perform further correlation analysis with the aim of determining the effects of metabolic disturbances on brain metabolism.

7.
Science ; 232(4754): 1106-12, 1986 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-17754498

RESUMEN

Light plays a pivotal role in the development of plants. The photoregulation of plant genes involves recognition of light quality and quantity by phytochrome and other light receptors. Two gene families, rbcS and Cab, which code for abundant proteins active in photosynthesis, the small subunit of ribulose bisphosphate carboxylase and the chlorophyll a/b binding protein, show a 20-to 50-fold increase in transcript abundance in the light. Analyses in calli and transgenic plants of deletions of the rbcS gene and of chimeric constructions has allowed localization of two regions involved in light-induced transcription. One element is confined to a 33-base pair region surrounding the TATA box. In addition, an enhancer-like element contained within a 240-base pair fragment can confer phytochrome-induced transcription and organ specificity on nonregulated promoters.

8.
Science ; 294(5544): 1108-11, 2001 Nov 02.
Artículo en Inglés | MEDLINE | ID: mdl-11691995

RESUMEN

The Arabidopsis thaliana response regulator 4, expressed in response to phytochrome B action, specifically interacts with the extreme amino-terminus of the photoreceptor. The response regulator 4 stabilizes the active Pfr form of phytochrome B in yeast and in planta, thus elevates the level of the active photoreceptor in vivo. Accordingly, transgenic Arabidopsis plants overexpressing the response regulator 4 display hypersensitivity to red light but not to light of other wavelengths. We propose that the response regulator 4 acts as an output element of a two-component system that modulates red light signaling on the level of the phytochrome B photoreceptor.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Luz , Células Fotorreceptoras , Fitocromo/metabolismo , Transducción de Señal , Factores de Transcripción , Arabidopsis/genética , Arabidopsis/efectos de la radiación , Proteínas de Arabidopsis/genética , Núcleo Celular/metabolismo , Citoplasma/metabolismo , Oscuridad , Genes de Plantas , Fenotipo , Fosforilación , Fitocromo/química , Fitocromo B , Plantas Modificadas Genéticamente , Conformación Proteica , Proteínas Recombinantes de Fusión/metabolismo , Técnicas del Sistema de Dos Híbridos , Levaduras/genética , Levaduras/metabolismo
9.
Acta Psychiatr Scand ; 119(3): 199-208, 2009 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-19016669

RESUMEN

OBJECTIVE: We tested the association between theory of mind (ToM) performance and structural changes in the brains of patients in the early course of schizophrenia. METHOD: Voxel-based morphometry (VBM) data of 18 patients with schizophrenia were compared with those of 21 controls. ToM skills were assessed by computerized faux pas (FP) tasks. RESULTS: Patients with schizophrenia performed significantly worse in FP tasks than healthy subjects. VBM revealed significantly reduced gray matter density in certain frontal, temporal and subcortical regions in patients with schizophrenia. Poor FP performance of schizophrenics correlated with gray matter reduction in the left orbitofrontal cortex and right temporal pole. CONCLUSION: Our data indicate an association between poor ToM performance and regional gray matter reduction in the left orbitofrontal cortex and right temporal pole shortly after the onset of schizophrenia.


Asunto(s)
Corteza Cerebral/patología , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Teoría de Construcción Personal , Esquizofrenia/diagnóstico , Psicología del Esquizofrénico , Adolescente , Adulto , Cerebelo/patología , Dominancia Cerebral/fisiología , Femenino , Lóbulo Frontal/patología , Hipocampo/patología , Humanos , Masculino , Pruebas Neuropsicológicas , Tamaño de los Órganos/fisiología , Escalas de Valoración Psiquiátrica , Valores de Referencia , Lóbulo Temporal/patología , Adulto Joven
10.
Aliment Pharmacol Ther ; 26(7): 1025-33, 2007 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-17877509

RESUMEN

BACKGROUND: A recent study reported that a non-synonymous single nucleotide polymorphism (rs11209026, p.Arg381Gln) located in the IL23R gene is a protective marker for inflammatory bowel disease. AIM: To analyse the frequency of p.Arg381Gln in three independent European inflammatory bowel disease cohorts and to evaluate how this variant influences disease behaviour. METHODS: We assessed a European cohort of 919 inflammatory bowel disease patients and compared the IL23R p.Arg381Gln genotype frequency with 845 healthy controls. Inflammatory bowel disease patients originated from Germany [Crohn's disease (CD): n = 318; ulcerative colitis (UC): n = 178], Hungary (CD: n = 148; UC: n = 118) and the Netherlands (CD: n = 157). Ethnically matched controls were included. We performed subtyping analysis in respect to CARD15 alterations and clinical characteristics. RESULTS: The frequency of the glutamine allele of p.Arg381Gln was significantly lower in inflammatory bowel disease patients compared with controls in a pooled analysis of all three cohorts (P < 0.000001) as well as in the individual cohorts (Germany: P = 0.001, Hungary: P = 0.02 and the Netherlands: P = 0.0002). The p.Arg381Gln genotype distribution was similar between CD and UC. We did not observe either statistical interactions between p.Arg381Gln and CARD15 variants or any significant associations between p.Arg381Gln genotype and subphenotypes. CONCLUSIONS: The p.Arg381Gln IL23R variant confers a protective effect against both CD and UC, but does not determine disease phenotype.


Asunto(s)
Colitis Ulcerosa/genética , Neoplasias del Colon/prevención & control , Enfermedad de Crohn/genética , Proteína Adaptadora de Señalización NOD2/genética , Polimorfismo de Nucleótido Simple/genética , Receptores de Interleucina/genética , Adulto , Estudios de Cohortes , Femenino , Tamización de Portadores Genéticos/métodos , Genotipo , Humanos , Masculino , Fenotipo , Receptores de Interleucina/análisis
11.
Plant Cell ; 11(8): 1445-56, 1999 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-10449579

RESUMEN

The phytochrome (phy) family of plant photoreceptors controls various aspects of photomorphogenesis. Overexpression of rice phyA-green fluorescent protein (GFP) and tobacco phyB-GFP fusion proteins in tobacco results in functional photoreceptors. phyA-GFP and phyB-GFP are localized in the cytosol of dark-adapted plants. In our experiments, red light treatment led to nuclear translocation of phyA-GFP and phyB-GFP, albeit with different kinetics. Red light-induced nuclear import of phyB-GFP, but not that of phyA-GFP, was inhibited by far-red light. Far-red light alone only induced nuclear translocation of phyA-GFP. These observations indicate that nuclear import of phyA-GFP is controlled by a very low fluence response, whereas translocation of phyB-GFP is regulated by a low fluence response of phytochrome. Thus, light-regulated nucleocytoplasmic partitioning of phyA and phyB is a major step in phytochrome signaling.

12.
Mol Cell Biol ; 18(4): 2038-44, 1998 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-9528776

RESUMEN

In mammalian cells, mitogen-induced phosphorylation of ribosomal protein S6 by p70s6k has been implicated in the selective translational upregulation of 5'TOP mRNAs. We demonstrate here that the homologous Arabidopsis thaliana protein, AtS6k2, ectopically expressed in human 293 cells or isolated from plant cells, phosphorylates specifically mammalian and plant S6 at 25 degrees C but not at 37 degrees C. When Arabidopsis suspension culture cells are shifted from 25 to 37 degrees C, the kinase becomes rapidly inactivated, consistent with the observation that heat shock abrogates S6 phosphorylation in plants. Treatment with potato acid phosphatase reduced the specific activity of immunoprecipitated AtS6k2 threefold, an effect which was blocked in the presence of 4-nitrophenyl phosphate. In quiescent mammalian cells, AtS6k2 is activated by serum stimulation, a response which is abolished by the fungal metabolite wortmannin but is resistant to rapamycin. Treatment of mammalian cells with rapamycin abolishes in vivo S6 phosphorylation by p70s6k; however, ectopic expression of AtS6k2 rescues the rapamycin block. Collectively, the data demonstrate that AtS6k2 is the functional plant homolog of mammalian p70s6k and identify a new signalling pathway in plants.


Asunto(s)
Arabidopsis/enzimología , Proteínas Quinasas S6 Ribosómicas/metabolismo , Secuencia de Aminoácidos , Anticuerpos/metabolismo , Arabidopsis/genética , Línea Celular , Células Cultivadas , ADN de Plantas/química , ADN de Plantas/aislamiento & purificación , Calor , Humanos , Riñón/embriología , Datos de Secuencia Molecular , Proteínas Quinasas S6 Ribosómicas/genética , Proteínas Quinasas S6 Ribosómicas/inmunología , Transducción de Señal
13.
Dig Liver Dis ; 39(12): 1064-70, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-17964870

RESUMEN

BACKGROUND: NOD1/CARD4, a member of the pattern-recognition receptor family, is a perfect candidate as a susceptibility gene for Crohn's disease. Since only limited and conflicting data are available on G796A polymorphisms in inflammatory bowel disease patients, we set out to study the effect of this polymorphism on the susceptibility and course of Crohn's disease in the Hungarian population. METHODS: Four hundred thirty-four unrelated Crohn's disease patients (age at presentation: 28.6+/-9.6 years, female/male: 210/224, duration of Crohn's disease: 8.2+/-6.9 years) and 200 healthy subjects (blood donors) and 136 non-inflammatory bowel disease gastrointestinal controls with chronic gastritis were investigated. NOD1 G796A was detected by using polymerase chain reaction/restriction fragment length polymorphism. Detailed clinical phenotypes were determined by reviewing the medical charts. RESULTS: The frequencies of the variant alleles of NOD1 G796A differed significantly between the Crohn's disease patients and both healthy (GG 49.5% vs. 67%; AG 41.5% vs. 28%; and AA 9.0% vs. 5.2%; p<0.0001) and non-inflammatory bowel disease controls with chronic gastritis. Carriage of the single nucleotide polymorphism of NOD1 G796A proved to be a highly significant risk factor for Crohn's disease compared to both healthy (p<0.0001, OR: 2.1, 95% CI: 1.5-2.9) and non-inflammatory bowel disease controls with chronic gastritis (p=0.008). Significant associations were not found between the different genotypes and the demographic data on the patients or the clinical characteristics of Crohn's disease. The different polymorphisms of pattern-recognition receptors (e.g. NOD2/CARD15 SNP8, SNP12 and SNP13 mutations, the TLR4 D299G polymorphism and NOD1 G796A) did not reveal a mutual basis. CONCLUSIONS: Our results suggest that carriage of the NOD1 G796A mutation increases susceptibility for Crohn's disease in the Hungarian population.


Asunto(s)
Enfermedad de Crohn/genética , Predisposición Genética a la Enfermedad , Proteína Adaptadora de Señalización NOD1/genética , Proteína Adaptadora de Señalización NOD2/genética , Polimorfismo de Nucleótido Simple , Adulto , Enfermedad de Crohn/diagnóstico , Enfermedad de Crohn/epidemiología , Femenino , Humanos , Hungría/epidemiología , Masculino
14.
Curr Opin Plant Biol ; 3(6): 450-4, 2000 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11074374

RESUMEN

The past year has brought significant changes in our understanding of the molecular mechanism of photoreceptor-regulated gene expression in higher plants. The light-quantity- and light-quality-dependent nuclear import of phytochromes, followed by the conformation-dependent direct interaction of these phytochromes with transcription factors, seems to play a major role in light-modulated plant growth and development.


Asunto(s)
Núcleo Celular/metabolismo , Fitocromo/metabolismo , Proteínas del Complejo del Centro de Reacción Fotosintética/metabolismo , Células Vegetales , Plantas/metabolismo , Transporte de Proteínas
15.
J Neurosci ; 19(17): 7309-16, 1999 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-10460237

RESUMEN

Approximately 28% of dorsal horn neurons (DHNs) in lamina V of the rat spinal cord generate voltage-dependent plateau potentials underlying accelerating discharges and prolonged afterdischarges in response to steady current pulses or stimulation of nociceptive primary afferent fibers. Using intracellular recordings in a transverse slice preparation of the cervical spinal cord, we have analyzed the ionic mechanisms involved in the generation and maintenance of plateau potentials in lamina V DHNs. Both the accelerating discharges and afterdischarges were reversibly blocked by Mn(2+) and enhanced when Ca(2+) was substituted with Ba(2+). The underlying tetrodotoxin-resistant regenerative depolarization was sensitive to dihydropyridines, being blocked by nifedipine and enhanced by Bay K 8644. Substitution of extracellular Na(+) with N-methyl-D-glucamine or choline strongly decreased the duration of the plateau potential. Loading the neurons with the calcium chelator BAPTA did not change the initial response but clearly decreased the maximum firing frequency and the duration of the afterdischarge. A similar effect was obtained with flufenamate, a specific blocker of the calcium-activated nonspecific cation current (I(CAN)). We conclude that the plateau potential of deep DHNs is supported by both Ca(2+) influx through intermediate-threshold voltage-gated calcium channels of the L-type and by subsequent activation of a CAN current. Ca(2+) influx during the plateau is potentially of importance for pain integration and the associated sensitization in spinal cord.


Asunto(s)
Potenciales Evocados/fisiología , Neuronas/fisiología , Médula Espinal/fisiología , Ácido 3-piridinacarboxílico, 1,4-dihidro-2,6-dimetil-5-nitro-4-(2-(trifluorometil)fenil)-, Éster Metílico/farmacología , Vías Aferentes/fisiología , Animales , Bario/farmacología , Calcio/farmacología , Quelantes/farmacología , Ácido Egtácico/análogos & derivados , Ácido Egtácico/farmacología , Potenciales Evocados/efectos de los fármacos , Femenino , Técnicas In Vitro , Masculino , Manganeso/farmacología , Potenciales de la Membrana/fisiología , Fibras Nerviosas/fisiología , Dolor/fisiopatología , Ratas , Ratas Wistar , Tetrodotoxina/farmacología
16.
Genetics ; 100(3): 487-95, 1982 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-17246066

RESUMEN

Chloroplasts of Nicotiana tabacum SR1 were transferred into Nicotiana plumbaginifolia by protoplast fusion. The protoplasts of the organelle donor were irradiated with different lethal doses using a (60)Co source, to facilitate the elimination of their nuclei from the fusion products. After fusion induction, clones derived from fusion products and containing streptomycin-resistant N. tabacum SR1 chloroplasts were selected by their ability to green on a selective medium. When N. tabacum protoplasts were inactivated by iodoacetate instead of irradiation, the proportion of N. plumbaginifolia nuclear segregant clones was low (1-2%). Irradiation markedly increased this value: Using 50, 120, 210 and 300 J kg(-1) doses, the frequency of segregant clones was 44, 57, 84 and 70 percent, respectively. Regeneration of resistant N. plumbaginifolia plants with SR1 chloroplasts indicated that plastids can be rescued from the irradiated cells by fusion with untreated protoplasts. Resistant N. plumbaginifolia plants that were regenerated (43 clones studied) had diploid (2n = 2X = 20) or tetraploid chromosome numbers and were identical morphologically to parental plants. The absence of aneuploids suggests that in these clones irradiation resulted in complete elimination of the irradiated N. tabacum nuclei. Resistance is inherited maternally (five clones tested). The demonstration of chloroplast transfer and the presence of N. tabacum plastids in the N. plumbaginifolia plants was confirmed by chloroplast DNA fragmentation patterns after EcoRI digestion.

17.
Plant Physiol ; 110(4): 1081-1088, 1996 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-12226242

RESUMEN

We have isolated a genomic clone from Nicotiana tabacum, designated Nt-PHYB-1, encoding a type-II, "green tissue" phytochrome apoprotein. Recombinant genes, consisting of the 3319-bp promoter of the Nt-PHYB-1 gene (including the entire 5[prime] untranslated sequence but not the ATG) or its deletion derivatives and the bacterial [beta]-glucuronidase reporter gene, were constructed and transferred into tobacco. The expression patterns and levels of the endogenous Nt-PHYB-1, as well as those of the transgenes, were determined by RNase protection assays and by [beta]-glucuronidase histochemical staining. We show that (a) the PHYB-1 gene has three transcription start sites, (b) the abundance of the three PHYB-1-specific mRNAs is different, and that (c) it is not regulated by light. However, we do demonstrate that transcription of the endogenous PHYB-1 gene and that of the recombinant genes exhibit a well-defined organ and tissue specificity. This tobacco PHYB gene is relatively highly expressed in leaf, stem, and different floral organs but not in root. Deletion analysis of the Nt-PHYB-1 promoter indicates that a 382-bp region, located between -1472 and -1089, is required for high-level expression of this gene.

18.
Neuropeptides ; 39(3): 223-31, 2005 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-15893817

RESUMEN

The 29/30 amino acid neuropeptide galanin is present in a small population of DRG neurons under normal condition but is strongly upregulated after nerve injury. There is evidence that this upregulated galanin has trophic actions, for example promoting neurite outgrowth as well as influencing pain processing. In fact, both pro- and antinociceptive effects have been reported, probably relating to activation of different receptors. It has been proposed that presynaptic GalR2 receptors are pro-nociceptive by enhancing release of excitatory transmitters in the dorsal horn, and anti-nociceptive via an action on GalR1-positive interneurons. These neurons have recently been shown to be glutamatergic. Several other peptides and molecules are also regulated by nerve injury. Here we focus on neuropeptide tyrosine (NPY), which is upregulated in parallel with galanin. We review data reporting on coexistence between galanin and NPY and between these two peptides and the two NPY receptors Y1 and Y2. The data show considerable overlap, and it will be an important task to analyse how cross-talk between these neuropeptides can influence pain processing. It is proposed that such cross-talk can occur by release of peptides from DRGs neuron somata within dorsal root ganglia. To what extent these mechanisms shown to exist in rodents also occur in human is important, if one wants to discuss novel strategies for pain treatment on the basis of these findings. So far information is limited, but it has been demonstrated that galanin is expressed in DRGs and possibly also regulated.


Asunto(s)
Galanina/fisiología , Ganglios Espinales/fisiología , Neuralgia/fisiopatología , Receptores de Galanina/fisiología , Médula Espinal/fisiología , Animales , Ganglios Espinales/citología , Humanos , Inmunohistoquímica , Fenotipo , Médula Espinal/citología
20.
Eur J Pain ; 19(9): 1288-97, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25766522

RESUMEN

BACKGROUND: Parkinson's disease (PD) is a neurodegenerative disorder mainly marked by selective degeneration of dopaminergic neurons that leads to disabling motor and cognitive impairment. This condition is less widely appreciated as a disease associated with a substantial variety of pain syndromes, although the prevalence of pain is relatively high. Repeated painful stimulation of peripheral nerves can cause pain 'wind-up' if the frequency of the stimulation is adequate and specifically stimulates the afferent C-fibres. We presumed that in case of PD, pain or pain severeness might be frequently caused by the aggravation of the 'wind-up' phenomenon due to any central or peripheral lesions or functional alterations. METHODS: To test for this hypothesis, we compared three groups (patients with left- and right-dominant PD and control subjects) using functional magnetic resonance imaging and thermally induced pain. RESULTS: Patient showed higher average 'wind-up' scores, compared to the healthy subjects, with lower values on the more affected sides compared to the less affected ones. In group level comparisons, patients had higher activation during 'wind-up' compared to control subjects in two main areas; these were the posterior division of cingulate gyrus and the precuneus cortex. In case of patients, further analyses showed that applied heat pain on the less affected side elicited higher activation in the supramarginal and postcentral gyri. CONCLUSIONS: These differences may arise from the deficiency in the efferent information, as well as the alterations in the central processing. It is highly likely that both processes contribute to this phenomenon simultaneously.


Asunto(s)
Giro del Cíngulo/fisiopatología , Imagen por Resonancia Magnética/métodos , Percepción del Dolor/fisiología , Dolor/fisiopatología , Lóbulo Parietal/fisiopatología , Enfermedad de Parkinson/fisiopatología , Anciano , Humanos , Masculino , Persona de Mediana Edad
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