RESUMO
BACKGROUND: Nurses are pivotal in averting patient falls through their assessment of cues presented by patients and their environments, rendering clinical judgments regarding the risk of falling, and implementing tailored interventions. Despite the intricate cognitive processes entailed in nurses' judgment, no prior studies have explored their approach to assessing the risk of falling. OBJECTIVE: This study aimed to examine how nurses judge the risk of falling among patients with different conditions, whether there are differences in the importance of risk factors as judged by nurses, how they justify their judgments, and what attributes of the nurses influence their judgments. DESIGN: A mixed method approach using the Q Methodology was employed. SETTING(S): Three public and private hospitals in Japan. PARTICIPANTS: Eighteen nurses participated in the study. METHODS: Participants were tasked with ranking 36 patient scenarios, each featuring a distinct set of fall risk factors. Subsequently, post-sorting interviews were conducted to gather insights into their typical approach to assessing fall risk and the rationale behind their ranking decisions. A by-person principal component factor extraction was employed to examine differences in the rankings of the scenarios. The interview data were analyzed descriptively to elucidate the reasons behind these discrepancies. RESULTS: Nurses engage in complex cognitive manipulations when evaluating the risk of patient falls, drawing extensively from their wealth of experience while utilizing assessment tools to support their judgments. In essence, nurses identify patients' tendency to act alone without calling a nurse, impaired gait and cognition, sedative use, drains, and limited information sharing among healthcare professionals as key fall risks. In addition, nurses vary in the importance they attribute to certain risk factors, leading to the discrimination of three distinct judgment profiles. One group of nurses judges patients with cognitive impairment and acting alone as high risk. Another group of nurses considers patients with unstable gait and acting alone as high risk. The last group of nurses sees patients wearing slippers as high risk. The post-sorting interviews revealed that their judgments are closely related to the healthcare context and patient population. CONCLUSIONS: Nurses operate within diverse contexts, wherein they interact with patients of varying characteristics, collaborate with professionals from diverse disciplines, and have access to varying levels of human and physical resources. This nuanced understanding empowers the formulation of judgments that are finely attuned to the specific context at hand. STUDY REGISTRATION: Not registered.
Assuntos
Acidentes por Quedas , Julgamento , Acidentes por Quedas/prevenção & controle , Humanos , Fatores de Risco , Recursos Humanos de Enfermagem Hospitalar/psicologia , Adulto , Feminino , Japão , Masculino , Pessoa de Meia-Idade , Medição de Risco/métodosRESUMO
BACKGROUND: While assessment made by nurses of themselves (self-assessment) and assessment made of them by others (other-assessment) provide unique and valuable information as to individual nurses' competence, the subjective nature of both assessments often causes a disagreement between them. This is problematic when educational interventions to foster nurses' competence are designed. However, the question of what factors contribute to the self-other disagreement in competence assessment has rarely been investigated in nursing. OBJECTIVES: The aims of this study were to compare competence assessments made by nurses with that by others, and to investigate what types of demographic variables of nurses and others, and which personality traits of nurses were associated with the self-other agreement/disagreement in the competence assessment. DESIGN: A cross-sectional survey design. SETTINGS: Three hospitals in Japan. PARTICIPANTS: A total of 1167 registered nurses, who were practising in these three hospitals, were invited to participate in the study. The inclusion criteria of the participants were as follows: 1) currently working in an inpatient department, and 2) directly involved in patient care. METHODS: The survey package included two sets of questionnaires: one for self-assessment and the other for other-assessment, each of which was accompanied by an ID number for matching. Collected data were analysed using a Wilcoxon signed-rank test to compare the scores on competence assessed by nurses and others, and using multiple regression to examine the relationships between the demographics, personality traits, and the degree of self-other disagreement. RESULTS: A total of 207 matched questionnaires were obtained. The results showed that the scores on the assessment made by others were statistically significantly higher than those made by nurses of themselves. Moreover, regression analysis suggested that the age of nurses (i.e., younger nurses) and that of others (i.e., older evaluators), and nurses' personality traits of conscientiousness and extraversion were statistically significantly related to the agreement in self-other competence assessment. CONCLUSIONS: Nurse managers need to understand which factors contribute to self-other disagreement in competence assessment, and to identify a way to precipitate mutual agreement between them. By doing so, both nurses and managers can comprehend nurses' own strengths and weaknesses, and can determine educational needs and goals regarding nurses' competence development.
Assuntos
Cuidados de Enfermagem , Competência Profissional , Estudos Transversais , Humanos , Japão , Autoavaliação (Psicologia)RESUMO
AIM: A good fit between an individual's personality traits and job characteristics motivates employees, and thus enhances their work behavior. However, how nurses' personality traits and their environmental characteristics relate to nurses' engagement in workplace learning, which improves their competence, has not been investigated. The aim of this study was to investigate how nurses' personality traits, environmental characteristics, and workplace learning were related to nursing competence. METHODS: A cross-sectional survey design was used. Questionnaires were distributed to 1167 Japanese registered nurses. Multiple regression analysis was used to examine the relationships between nurses' personality traits, the environmental characteristics, the nurses' engagement in workplace learning, and their competence. RESULTS: A total of 315 nurses returned questionnaires (i.e., a return rate of 27.0%). The results showed that both the personality traits (extraversion, conscientiousness, openness to experience) and environmental characteristics (autonomy at work and feedback given) were related to workplace learning and self-rated nursing competence. The results also showed that the relationship between extraversion (active, adventurous and ambitious dispositions of an individual) and self-rated nursing competence was moderated by environmental characteristics, and partially mediated by workplace learning. CONCLUSION: Positive personality traits, such as extraversion, conscientiousness, and openness to experience could enhance workplace learning and nursing competence. Moreover, environmental characteristics that allow nurses to express their personality traits have the potential to improve their learning and competence further.
Assuntos
Aprendizagem , Recursos Humanos de Enfermagem/psicologia , Personalidade , Competência Profissional , Local de Trabalho , Adulto , Estudos Transversais , Feminino , Humanos , Japão , Masculino , Pessoa de Meia-Idade , Motivação , Inquéritos e QuestionáriosRESUMO
The embryonic diaphragm comprises four major structural components derived from the transverse septum, the dorsal foregut mesentery, the pleuroperitoneal folds (PPFs), and the body wall. In this study, the appearance of PPFs and related factors were investigated using light microscopy of horizontal sections of rat fetuses from embryonic day 12 to 13. In rat fetuses, the sign of PPF projection was noted in the sidewall of the pericardioperitoneal canal at embryonic day 12, and was confirmed as folds at embryonic day 12.25. Expressions of GATA4, COUP-TF2, and FOG2 were detected in PPF at the early stage of formation. Localizations of these factors suggested that COUP-TF2 and FOG2 are the main factors in PPF appearance and that GATA4 is unlikely to be a main factor, although it is necessary for PPF formation.
Assuntos
Diafragma/embriologia , Regulação da Expressão Gênica no Desenvolvimento , Animais , Fator II de Transcrição COUP/genética , Diafragma/metabolismo , Feminino , Desenvolvimento Fetal , Fator de Transcrição GATA4/genética , Hérnias Diafragmáticas Congênitas/embriologia , Hérnias Diafragmáticas Congênitas/genética , Imuno-Histoquímica , Masculino , Ratos Wistar , Fatores de Transcrição/genéticaRESUMO
With the growing focus on continuous professional development, demands placed on nurses to uphold nursing competence have been increasing. This study examined how nurses with different lengths of clinical experience perceived the relationship between their actual competence and the competence they felt was demanded of them, and how this relationship was related to their turnover intentions. Survey questionnaires were distributed to 1,377 nurses, of whom 765 returned usable completed forms. The results showed that across all the groups of clinical experience, nurses perceived the demanded competence levels to be higher than their actual competence levels. However, turnover intentions were not related to nurses' perceptions of demanded competence and were negatively related to perceptions of actual competence. The levels of competence demanded should not be considered as threats for nurses. Improving nurses' competence may reduce their turnover intentions.
Assuntos
Competência Clínica/normas , Satisfação no Emprego , Enfermeiras e Enfermeiros/psicologia , Percepção , Adulto , Atitude do Pessoal de Saúde , Estudos Transversais , Feminino , Humanos , Intenção , Masculino , Análise Multivariada , Enfermeiras e Enfermeiros/normas , Reorganização de Recursos Humanos/tendências , Psicometria/instrumentação , Psicometria/métodos , Análise de Regressão , Inquéritos e QuestionáriosRESUMO
Brain-derived neurotrophic factor (BDNF) is a principal factor for neurogenesis, neurodevelopment and neural survival through a BDNF receptor, tropomyosin-related kinase (Trk) B, while BDNF can also cause a decrease in the intracellular glutathione (GSH) level. We investigated the exacerbation of methylmercury-induced death of rat cerebellar granular neurons (CGNs) by BDNF in vitro. Since methylmercury can decrease intracellular GSH levels, we hypothesized that a further decrease of the intracellular GSH level is involved in the process of the exacerbation of neuronal cell death. In the present study, we established that in CGN culture, a decrease of the intracellular GSH level was further potentiated with BDNF in the process of the methylmercury-induced neuronal death and also in GSH reducer-induced neuronal death. BDNF treatment promoted the decrease in GSH levels induced by methylmercury and also by L-buthionine sulfoximine (BSO) and diethyl maleate (DEM). The promoting effect of BDNF was observed in a TrkB-vector transformant of the rat neuroblastoma B35 cell line but not in the mock-vector transformant. These results indicate that the exacerbating effect of BDNF on methylmercury-induced neuronal death in cultures of CGNs includes a further decrease of intracellular GSH levels, for which TrkB is essential.
Assuntos
Fator Neurotrófico Derivado do Encéfalo/toxicidade , Glutationa/metabolismo , Compostos de Metilmercúrio/toxicidade , Neurônios/efeitos dos fármacos , Receptor trkB/metabolismo , Animais , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Cerebelo/citologia , Sinergismo Farmacológico , Neurônios/metabolismo , RatosRESUMO
BACKGROUND: Nurses have to maintain and improve their nursing competence in order to provide the best patient care possible. Workplace learning has the potential to improve nursing competence. Previous studies have examined the effect of training on competence development. However, the effects of other aspects of learning, such as learning from practice, feedback, reflection, and from others have not been investigated previously. Furthermore, it is uncertain what methods of learning nurses with different clinical experience adopt and how these learning methods relate to their self-reported competence. OBJECTIVES: The objectives of this study were to identify the methods of learning used by less and more experienced nurses, and to explore what methods of workplace learning would be associated with the self-reported competence of both groups of nurses. DESIGN: A cross-sectional survey design was utilised. SETTINGS: The study was conducted at two university-affiliated hospitals in Japan. PARTICIPANTS: A convenience sample of 954 nurses/midwives (hereafter referred to as nurses), who were involved in direct patient care, were recruited and 494 nurses returned usable questionnaires. METHODS: A survey method was used to collect data. The Holistic Nursing Competence Scale, the Learning Experience Scale and the Japanese version of Rosenberg's Self-esteem Scale, along with demographic questions, were included in the questionnaire. Hierarchical regression analysis was conducted to investigate the relationship between learning and nurses' self-evaluation of competence. This analysis was carried out for less experienced nurses (≤5 years of clinical experience) and experienced nurses (>5 years of experience). RESULTS: The results showed that learning was correlated with the levels of competence that nurses considered they had. When the specific types of learning were examined in relation to self-reported competence, there were a similarity and differences between less and more experienced nurses. For both groups of nurses, learning through reflection was found to relate to their self-reported competence. In addition, learning through practice and learning from others were positively correlated with the self-reported competence of less experienced nurses, while learning from feedback and training were positively associated with the self-reported competence of experienced nurses. CONCLUSION: Learning from reflection may be useful for both less and more experienced nurses by allowing them to embrace a positive view of their competence. Moreover, creating opportunities to experiment and observe others' practice can be profitable for less experienced nurses, while offering training opportunities and feedback can be beneficial for experienced nurses.
Assuntos
Educação em Enfermagem , Capacitação em Serviço , Tocologia/educação , Competência Profissional , Estudos Transversais , Enfermagem Holística/normas , Aprendizagem , Competência Profissional/normas , AutorrelatoRESUMO
OBJECTIVE: Brain-derived neurotrophic factor (BDNF) binds to its high-affinity binding receptor, tropomyosin-related kinase (Trk) B, and can induce neuronal differentiation and survival. BDNF also accelerates neuronal cell death in a glutamate-induced model; however, it has been unknown whether the mechanism involves TrkB. In the current study, to determine the role of TrkB in neuronal cell death, we investigated TrkB involvement in BDNF acceleration of glutamate-induced neuronal death. METHODS: A TrkB-stable transformant of rat neuroblastoma B35 (B35(TrkB)) cells was utilized to investigate whether TrkB is involved in BDNF acceleration of neuronal death. The cell viability of the B35(TrkB) cells was compared to that of mock vector-transgened B35 (B35(mock)) cells after treatment with/without BDNF and glutamate. RESULTS: In both B35(TrkB) and B35(mock) cells, glutamate treatment decreased the cell viability. BDNF treatment further accelerated the decrease in the viability of B35(TrkB) cells, but not that in the viability of B35(mock) cells. At glutamate concentrations that did not significantly decrease cell viability, BDNF increased the cell viability of B35(TrkB), but not that of B35(mock). A mitogen-activated protein kinase (MAPK) inhibitor, U0126, suppressed BDNF's accelerating effect on cell death. Although B35 parental cells endogenously express other neurotrophin receptors such as TrkA, nerve growth factor ß (a ligand of TrkA and p75(NTR)) could not influence the viability of B35(TrkB) or B35(mock) cells. CONCLUSION: These results indicate that TrkB is an intermediator for the trophic and toxicity-exacerbating effects of BDNF against cell viabilities at non-cytotoxic and cytotoxic glutamate concentrations, respectively.
Assuntos
Fator Neurotrófico Derivado do Encéfalo/metabolismo , Morte Celular/fisiologia , Ácido Glutâmico/metabolismo , Neurônios/fisiologia , Receptor trkB/metabolismo , Animais , Butadienos/farmacologia , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Inibidores Enzimáticos/farmacologia , MAP Quinases Reguladas por Sinal Extracelular/antagonistas & inibidores , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Fator de Crescimento Neural/metabolismo , Neuroblastoma/fisiopatologia , Neurônios/efeitos dos fármacos , Nitrilas/farmacologia , Ratos , Receptor trkA/metabolismo , Receptor trkB/genéticaRESUMO
BACKGROUND: A degree programme is believed to prepare graduates with a higher level of competence than their diploma counterparts. However, there have been inconsistent findings reported as to whether or not degree-graduates outperformed those who take diplomas. OBJECTIVES: This study aimed to identify graduates' perceptions of competence development in their first year of employment, and to compare the competence levels of graduates with different educational backgrounds. DESIGN: This study adopted a longitudinal design. SETTINGS: This study has been performed in five hospitals in Japan. PARTICIPANTS: 122 Japanese graduates participated in this study. METHODS: The self-assessed competence of the graduates was collected in the 3rd, 6th, 9th, and 12th months of their employment using a survey method. The data were analysed using a linear mixed model. RESULTS: The results suggested that the graduates perceived their competence to be rapidly growing during the first half of the graduate year, and slowly later. The results also indicated that the graduates' perception of their competence showed a significant variation. The most striking finding of the study was that, on average, the non-degree graduates rated their competence higher than their degree counterparts. CONCLUSIONS: The current university orientation on emphasising intellectual and theoretical components of education, with less focus on practical components might have led to the development of lower competence among the BN graduates. A fine balance between theoretical and practical components needs to be established in a university curriculum.
Assuntos
Competência Clínica , Enfermeiras e Enfermeiros/psicologia , Autoavaliação (Psicologia) , Bacharelado em Enfermagem , Emprego , Feminino , Humanos , Japão , Estudos Longitudinais , Masculino , Inquéritos e QuestionáriosRESUMO
The main target of neurotoxins is neurons because they comprise the main part of neural function, but glial cells may be indirect targets because they support the function of neurons. Among the glial cells, astrocytes in particular act as "nurse cells", regulating neuronal survival and functions. In the present study, to reveal whether a known neurotoxic substance, organophosphate dichlorvos (DDVP), affects the differentiation of astrocytes, we used an astrocyte differentiation model in rat glioma C6 cells. Morphological change and induction of GFAP expression in the differentiating C6 cells were suppressed by DDVP treatment. The known potential targets of DDVP are acetylcholine esterase (AChE), fatty acid amide hydrolase and methyl guanine methyl transferase. Among the specific inhibitors against these enzymes, the AChE inhibitor paraoxon successfully suppressed the cellular morphological changes and the induction of GFAP expression in differentiating C6 cells. These results indicate that DDVP inhibits differentiation in the C6 astrocyte-differentiation model, in which at least AChE inhibition is involved and that AChE is a potent regulator of the differentiation. Furthermore, considering that the main substrate of AChE is ACh, thus, ACh may act as regulators of astrocyte differentiation.
Assuntos
Acetilcolinesterase/metabolismo , Astrócitos/citologia , Diferenciação Celular/efeitos dos fármacos , Diclorvós/farmacologia , Proteína Glial Fibrilar Ácida/efeitos dos fármacos , Glioma/patologia , Animais , Astrócitos/efeitos dos fármacos , Diferenciação Celular/fisiologia , AMP Cíclico/metabolismo , Proteína Glial Fibrilar Ácida/metabolismo , Glioma/metabolismo , Ratos , Células Tumorais CultivadasRESUMO
Hepatic stellate cells (HSCs) intracellularly preserve vitamin A in the normal liver. When the liver is damaged, HSCs transform into myofibroblast-like cells, and then proliferate and increase their expression of collagen. Cultured on a plastic plate, HSCs spontaneously activate. To maintain HSCs in a quiescent state with low expression of collagen, coating methods with extracellular matrixes (ECMs) such as Matrigel-coating or laminin-rich coating are commonly used for HSC cultivation. Kishimoto et al. [14] reported that Fragmin®/protamine microparticles (F/P-MPs) have the ability to absorb heparin-binding cytokines like ECMs. Therefore, we examined whether the cultivation on an F/P-MPs-coated plate maintains the quiescent state of RI-T cells (derived from rat HSCs) including the suppression of collagen expression. We found that the mRNA levels of collagen type IαI and TGF-ß1 in RI-T cells were significantly suppressed in the cultivation on F/P-MPs-coated plates compared to cultures on noncoated and Matrigel-coated plates. We conclude that the F/P-MPs coating method is useful for maintaining with low expressions of collagen IαI and TGF-ß 1 mRNA levels in HSCs.
Assuntos
Técnicas de Cultura de Células/métodos , Colágeno Tipo I/metabolismo , Dalteparina/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Células Estreladas do Fígado/metabolismo , Protaminas/farmacologia , Fator de Crescimento Transformador beta1/metabolismo , Análise de Variância , Animais , Micropartículas Derivadas de Células/metabolismo , Colágeno , Primers do DNA/genética , Combinação de Medicamentos , Laminina , Proteoglicanas , Ratos , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
OBJECTIVE: Pregnant women often report complaints due to physiological and postural changes. Postural changes during pregnancy may cause low back pain and pelvic girdle pain. This study aimed to compare the characteristics of postural changes in pregnant compared with non-pregnant women. DESIGN: Prospective case-control study. SETTING: Pregnancy care center. POPULATION: Fifteen women at 17-34 weeks pregnancy comprised the study group, while 10 non-pregnant female volunteers comprised the control group. METHODS: Standing posture was evaluated in the sagittal plane with static digital pictures. Two angles were measured by image analysis software: (1) between the trunk and pelvis; and (2) between the trunk and lower extremity. Spinal curvature was measured with Spinal Mouse® to calculate the means of sacral inclination, thoracic and lumbar curvature and inclination. MAIN OUTCOME MEASURES: The principal components were calculated until eigenvalues surpassed 1. RESULTS: Three distinct factors with eigenvalues of 1.00-2.49 were identified, consistent with lumbosacral spinal curvature and inclination, thoracic spine curvature, and inclination of the body. These factors accounted for 77.2% of the total variance in posture variables. Eleven pregnant women showed postural characteristics of lumbar kyphosis and sacral posterior inclination. Body inclination showed a variety of patterns compared with those in healthy women. CONCLUSIONS: Spinal curvature demonstrated a tendency for lumbar kyphosis in pregnant women. Pregnancy may cause changes in spinal curvature and posture, which may in turn lead to relevant symptoms. Our data provide a basis for investigating the effects of spinal curvature and postural changes on symptoms during pregnancy.
Assuntos
Postura/fisiologia , Curvaturas da Coluna Vertebral/fisiopatologia , Adolescente , Adulto , Estudos de Casos e Controles , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Fotografação , Gravidez , Análise de Componente Principal , Estudos ProspectivosRESUMO
Our previous studies demonstrated that prenatal diethylstilbestrol (DES) treatment disrupts steroidogenesis but induces high-level expression of androgen receptor (AR) mRNA to inhibit the disruption of spermatogenesis. This study examined which prenatal DES treatment influenced hepatic microsomal enzymes, CYP3A1, CYP2B1/2, CYP2C11, UGT2B1 (UDP-glucuronosyltransferase 2B1), and IGF-1 (insulin-like growth factor-1), in male rat offspring. DES treatment decreased the mRNA expression levels of CYP3A1 and CYP2B1/2, but did not alter the expression of CYP2C11. At 6 weeks, DES treatment increasd the mRNA expression levels of UGT2B1 and IGF-1. These results suggest that prenatal DES treatment alters two hepatic enzymes (CYP3A1 and CYP2B1/2) and IGF-1 mRNA expression levels to counteract the low level of testosterone, but this disrupted UGT2B1 mRNA expression reduces the testosterone level.
Assuntos
Dietilestilbestrol/farmacologia , Estrogênios não Esteroides/farmacologia , Fígado/efeitos dos fármacos , Exposição Materna , Animais , Hidrocarboneto de Aril Hidroxilases/genética , Hidrocarboneto de Aril Hidroxilases/metabolismo , Citocromo P-450 CYP2B1/genética , Citocromo P-450 CYP2B1/metabolismo , Citocromo P-450 CYP3A/genética , Citocromo P-450 CYP3A/metabolismo , Família 2 do Citocromo P450 , Feminino , Regulação Enzimológica da Expressão Gênica , Fator de Crescimento Insulin-Like I/genética , Fator de Crescimento Insulin-Like I/metabolismo , Fígado/enzimologia , Fígado/metabolismo , Masculino , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/enzimologia , Microssomos Hepáticos/metabolismo , Gravidez , RNA Mensageiro/química , RNA Mensageiro/genética , Ratos , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Esteroide 16-alfa-Hidroxilase/genética , Esteroide 16-alfa-Hidroxilase/metabolismoRESUMO
Vitamin K (VK) has a protective effect on neural cells. Methylmercury is a neurotoxicant that directly induces neuronal death in vivo and in vitro. Therefore, in the present study, we hypothesized that VK inhibits the neurotoxicity of methylmercury. To prove our hypothesis in vitro, we investigated the protective effects of VKs (phylloquinone, vitamin K(1); menaquinone-4, vitamin K(2) ) on methylmercury-induced death in primary cultured neurons from the cerebella of rat pups. As expected, VKs inhibited the death of the primary cultured neurons. It has been reported that the mechanisms underlying methylmercury toxicity involve a decrement of intracellular glutathione (GSH). Actually, treatment with GSH and a GSH inducer, N-acetyl cysteine, inhibited methylmercury-induced neuronal death in the present study. Thus, we investigated whether VKs also have protective effects against GSH-depletion-induced cell death by employing two GSH reducers, L-buthionine sulfoximine (BSO) and diethyl maleate (DEM), in primary cultured neurons and human neuroblastoma IMR-32 cells. Treatment with VKs affected BSO- and DEM-induced cell death in both cultures. On the other hand, the intracellular GSH assay showed that VK(2), menaquinone-4, did not restore the reduced GSH amount induced by methylmercury or BSO treatments. These results indicate that VKs have the potential to protect neurons against the cytotoxicity of methylmercury and agents that deplete GSH, without increasing intracellular GSH levels. The protective effect of VKs may lead to the development of treatments for neural diseases involving GSH depletion.
Assuntos
Intoxicação do Sistema Nervoso por Mercúrio/prevenção & controle , Compostos de Metilmercúrio/antagonistas & inibidores , Degeneração Neural/tratamento farmacológico , Fármacos Neuroprotetores/farmacologia , Vitamina K/farmacologia , Animais , Animais Recém-Nascidos , Morte Celular/efeitos dos fármacos , Morte Celular/fisiologia , Linhagem Celular Tumoral , Modelos Animais de Doenças , Humanos , Técnicas In Vitro , Intoxicação do Sistema Nervoso por Mercúrio/metabolismo , Intoxicação do Sistema Nervoso por Mercúrio/patologia , Compostos de Metilmercúrio/toxicidade , Degeneração Neural/induzido quimicamente , Degeneração Neural/patologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Fármacos Neuroprotetores/uso terapêutico , Ratos , Ratos Wistar , Vitamina K/análogos & derivados , Vitamina K/uso terapêuticoRESUMO
CONCLUSION: Vestibular-evoked myogenic potential (VEMP) can be used to examine endolymphatic hydrops, especially in the vestibule. OBJECTIVE: To investigate the relationship between the degree of endolymphatic hydrops revealed by magnetic resonance imaging (MRI) and VEMP. METHODS: Gadolinium diluted with saline was injected intratympanically in 49 ears (40 patients). One day after the injection, the endolymphatic space in the vestibule and the cochlea was visualized by 3 Tesla MRI. A VEMP test was done, and VEMP was judged as absent when the VEMP was within the noise level. RESULTS: VEMP was present in 21 ears and absent in 28 ears. Endolymphatic hydrops was significantly associated with the disappearance of VEMP. Endolymphatic hydrops in the vestibule had a stronger effect than endolymphatic hydrops in the cochlea. Five patients with extremely large vestibular hydrops showed no response of VEMP.
Assuntos
Potenciais Evocados , Gadolínio , Imageamento por Ressonância Magnética , Doença de Meniere/diagnóstico , Gadolínio/administração & dosagem , HumanosRESUMO
Previous studies have shown that the dilating effect of nitric oxide (NO) on the fetal ductus arteriosus (DA) is age dependent and more marked in the premature stages in rats, but the factors that mediate this effect are poorly understood. The purpose of this study is to determine the changes in the expression of NO synthase (NOS) mRNA in the fetal DA and to examine the effect of an 11-beta-hydroxylase inhibitor of corticosterone synthesis, namely, metyrapone, on NOS expression. NOS 3 mRNA expression was observed in 17.5-day-old rat fetuses; thereafter, its level significantly increased and reached its peak on day 19.5 and then decreased until the end of the gestation period (day 21.5). To inhibit corticosterone synthesis, a constant infusion of metyrapone was administered to rats; this significantly decreased the fetal plasma corticosterone concentration as well as NOS 3 mRNA expression in the DA in a time-dependent manner. These results indicate that NO is generated by NOS 3 in the DA and that the age-dependant expression of NOS 3 in the premature DA is attributable to corticosterone-associated activity.
Assuntos
Corticosterona/biossíntese , Canal Arterial/enzimologia , Óxido Nítrico Sintase Tipo III/genética , Envelhecimento , Animais , Corticosterona/fisiologia , Canal Arterial/embriologia , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Regulação Enzimológica da Expressão Gênica , Gliceraldeído-3-Fosfato Desidrogenases/genética , Gravidez , Artéria Pulmonar/embriologia , Artéria Pulmonar/enzimologia , RNA Mensageiro/genética , Ratos , Ratos WistarRESUMO
The purpose of this study was to evaluate the relationship between the endolymphatic space image obtained using magnetic resonance imaging (MRI) and the results of electrocochleography. Electrocochleography recordings were obtained from 25 ears of 24 patients, who underwent MRI 1 day after the intratympanic injection of gadolinium diethylenetriamine pentaacetic acid bismethylamide. The average summating potential to action potential (SP/AP) ratio in patients with significant endolymphatic hydrops in the cochlea was 54 +/- 17%. However, in some patients who had significant endolymphatic hydrops in the cochlea, the SP/AP ratio was not enlarged. This may imply that elevation of the SP/AP ratio is related to not only the degree of endolymphatic hydrops but also to the persistence of hydrops.