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1.
PLoS One ; 15(10): e0240719, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33057427

RESUMO

How much can we rely on whether what was reported in a study was actually done? Systematic and independent examination of records, documents and processes through audits are a central element of quality management systems. In the context of current concerns about the robustness and reproducibility of experimental biomedical research audits have been suggested as a remedy a number of times. However, audits are resource intense and time consuming, and due to their very nature may be perceived as inquisition. Consequently, there is very little experience or literature on auditing and assessments in the complex preclinical biomedical research environment. To gain some insight into which audit approaches might best suit biomedical research in academia, in this study we have applied a number of them in a typical academic neuroscience environment consisting of twelve research groups with about 100 researchers, students and technicians, utilizing the full gamut of state-of-the-art methodology. Several types of assessments and internal as well as external audits (including the novel format of a peer audit) were systematically explored by a team of quality management specialists. An experimental design template was developed (and is provided here) that takes into account and mitigates difficulties, risks and systematic errors that may occur during the course of a study. All audits were performed according to a pre-defined workflow developed by us. Outcomes were assessed qualitatively. We asked for feedback from participating employees in every final discussion of an audit and documented this in the audit reports. Based on these reports follow-up audits were improved. We conclude that several realistic options for auditing exist which have the potential to improve preclinical biomedical research in academia, and have listed specific recommendations regarding their benefits and provided practical resources for their implementation (e.g. study design and audit templates, audit workflow).


Assuntos
Pesquisa Biomédica/normas , Auditoria Médica/normas , Estudos de Viabilidade , Humanos , Neurologia , Autoavaliação (Psicologia)
2.
J Cereb Blood Flow Metab ; 40(6): 1274-1289, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-31280632

RESUMO

Focal brain ischemia is best studied in neocortex and striatum. Both show highly vulnerable neurons and high susceptibility to spreading depolarization (SD). Therefore, it has been hypothesized that these two variables generally correlate. However, this hypothesis is contradicted by findings in cerebellar cortex, which contains highly vulnerable neurons to ischemia, the Purkinje cells, but is said to be less susceptible to SD. Here, we found in the rat cerebellar cortex that elevated K+ induced a long-lasting depolarizing event superimposed with SDs. Cerebellar SDs resembled those in neocortex, but negative direct current (DC) shifts and regional blood flow responses were usually smaller. The K+ threshold for SD was higher in cerebellum than in previous studies in neocortex. We then topically applied endothelin-1 (ET-1) to the cerebellum, which is assumed to cause SD via vasoconstriction-induced focal ischemia. Although the blood flow decrease was similar to that in previous studies in neocortex, the ET-1 threshold for SD was higher. Quantitative cell counting found that the proportion of necrotic Purkinje cells was significantly higher in ET-1-treated rats than sham controls even if ET-1 had not caused SDs. Our results suggest that ischemic death of Purkinje cells does not require the occurrence of SD.


Assuntos
Isquemia Encefálica/patologia , Isquemia Encefálica/fisiopatologia , Cerebelo/patologia , Cerebelo/fisiopatologia , Depressão Alastrante da Atividade Elétrica Cortical/fisiologia , Células de Purkinje/patologia , Animais , Isquemia Encefálica/induzido quimicamente , Depressão Alastrante da Atividade Elétrica Cortical/efeitos dos fármacos , Modelos Animais de Doenças , Endotelina-1/toxicidade , Masculino , Ratos , Ratos Wistar
3.
MAGMA ; 32(1): 105-114, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30421249

RESUMO

INTRODUCTION: We explored the use of a perfluoro-15-crown-5 ether nanoemulsion (PFC) for measuring tissue oxygenation using a mouse model of vascular cognitive impairment. METHODS: Seventeen C57BL/6 mice underwent stereotactic injection of PFC coupled to a fluorophore into the striatum and corpus callosum. Combined 1H/19F magnetic resonance imaging (MRI) to localize the PFC and R1 mapping to assess pO2 were performed. The effect of gas challenges on measured R1 was investigated. All mice then underwent bilateral implantation of microcoils around the common carotid arteries to induce global cerebral hypoperfusion. 19F-MRI and R1 mapping were performed 1 day, 1 week, and 4 weeks after microcoil implantation. In vivo R1 values were converted to pO2 through in vitro calibration. Tissue reaction to the PFC was assessed through ex vivo immunohistochemistry of microglial infiltration. RESULTS: R1 increased with increasing oxygen concentrations both in vitro and in vivo and the strength of the 19F signal remained largely stable over 4 weeks. In the two mice that received all four scans, tissue pO2 decreased after microcoil implantation and recovered 4 weeks later. We observed infiltration of the PFC deposits by microglia. DISCUSSION: Despite remaining technical challenges, intracerebrally injected PFC is suitable for monitoring brain oxygenation in vivo.


Assuntos
Encéfalo/metabolismo , Transtornos Cognitivos/diagnóstico por imagem , Disfunção Cognitiva/diagnóstico por imagem , Imagem por Ressonância Magnética de Flúor-19/instrumentação , Flúor/química , Oxigênio/metabolismo , Animais , Calibragem , Corpo Caloso/diagnóstico por imagem , Corpo Estriado/diagnóstico por imagem , Éteres de Coroa , Modelos Animais de Doenças , Emulsões , Imagem por Ressonância Magnética de Flúor-19/métodos , Fluorocarbonos/química , Processamento de Imagem Assistida por Computador , Pulmão/química , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Nanopartículas/química , Ondas de Rádio , Reprodutibilidade dos Testes
4.
Artigo em Inglês | MEDLINE | ID: mdl-29335365

RESUMO

The goal of this study was to develop and validate a measure of maximal telomerase activity capacity (mTAC) for use in human studies of telomere biology, and to determine its association with measures of stress and stress responsivity. The study was conducted in a population of 28 healthy young women and men who were assessed serially across two separate days, at multiple time points, and in response to a standardized laboratory stressor. Venous blood was collected at each of these multiple assessments, and an in vitro mitogen challenge (phytohaemagglutinin supplemented with interleukin-2) was used to stimulate telomerase activity in leucocytes. After first establishing the optimal post-stimulation time course to characterize mTAC, we determined the within-subject stability and the between-subject variability of mTAC. The major findings of our study are as follows: (i) the optimal time point to quantify human leucocyte mTAC appears to be at 72 h after mitogen stimulation; (ii) mTAC exhibits substantial within-subject stability (correlations were in the range of r 0.68-0.82) and between-subject variability, with a high intra-class coefficient (0.70), indicating greater between-subject relative to within-subject variability; (iii) mTAC is not influenced by situational factors including time of day, cortisol, acute stress exposure and immune cell distribution in the pre-stimulation blood sample; and (iv) a significant proportion of the between-subject variability in mTAC is associated with measures of stress and stress responsivity (mTAC is lower in subjects reporting higher levels of perceived (chronic) stress and exhibiting higher psychophysiological stress reactivity). Based collectively on these findings, it appears that mTAC, as proposed and operationalized, empirically meets the key criteria to represent a potentially useful individual difference measure of telomerase activity capacity of human leucocytes.This article is part of the theme issue 'Understanding diversity in telomere dynamics'.


Assuntos
Leucócitos/efeitos dos fármacos , Estresse Psicológico , Telomerase/metabolismo , Hormônio Adrenocorticotrópico/sangue , Adulto , Variação Biológica da População , Índice de Massa Corporal , Feminino , Humanos , Hidrocortisona/sangue , Masculino , Mitógenos/farmacologia , Fito-Hemaglutininas/farmacologia , Saliva/efeitos dos fármacos , Inquéritos e Questionários , Telômero/metabolismo
5.
PLoS Biol ; 14(12): e2000705, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27906976

RESUMO

We here propose the implementation of a simple and effective method to enhance the quality of basic and preclinical academic research: critical incident reporting (CIR). CIR has become a standard in clinical medicine but to our knowledge has never been implemented in the context of academic basic research. We provide a simple, free, open-source software tool for implementing a CIR system in research groups, laboratories, or large institutions (LabCIRS). LabCIRS was developed, tested, and implemented in our multidisciplinary and multiprofessional neuroscience research department. It is accepted by all members of the department, has led to the emergence of a mature error culture, and has made the laboratory a safer and more communicative environment. Initial concerns that implementation of such a measure might lead to a "surveillance culture" that would stifle scientific creativity turned out to be unfounded.


Assuntos
Laboratórios , Gestão de Riscos , Humanos , Cultura Organizacional
6.
F1000Res ; 5: 2, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26835004

RESUMO

Every professional doing active research in the life sciences is required to keep a laboratory notebook. However, while science has changed dramatically over the last centuries, laboratory notebooks have remained essentially unchanged since pre-modern science. We argue that the implementation of electronic laboratory notebooks (eLN) in academic research is overdue, and we provide researchers and their institutions with the background and practical knowledge to select and initiate the implementation of an eLN in their laboratories. In addition, we present data from surveying biomedical researchers and technicians regarding which hypothetical features and functionalities they hope to see implemented in an eLN, and which ones they regard as less important. We also present data on acceptance and satisfaction of those who have recently switched from paper laboratory notebook to an eLN.  We thus provide answers to the following questions: What does an electronic laboratory notebook afford a biomedical researcher, what does it require, and how should one go about implementing it?

7.
Proc Natl Acad Sci U S A ; 109(5): 1518-23, 2012 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-22233811

RESUMO

The metabolic state of a cell is a key determinant in the decision to live and proliferate or to die. Consequently, balanced energy metabolism and the regulation of apoptosis are critical for the development and maintenance of differentiated organisms. Hypoxia occurs physiologically during development or exercise and pathologically in vascular disease, tumorigenesis, and inflammation, interfering with homeostatic metabolism. Here, we show that the hypoxia-inducible factor (HIF)-1-regulated glycolytic enzyme hexokinase II (HKII) acts as a molecular switch that determines cellular fate by regulating both cytoprotection and induction of apoptosis based on the metabolic state. We provide evidence for a direct molecular interactor of HKII and show that, together with phosphoprotein enriched in astrocytes (PEA15), HKII inhibits apoptosis after hypoxia. In contrast, HKII accelerates apoptosis in the absence of PEA15 and under glucose deprivation. HKII both protects cells from death during hypoxia and functions as a sensor of glucose availability during normoxia, inducing apoptosis in response to glucose depletion. Thus, HKII-mediated apoptosis may represent an evolutionarily conserved altruistic mechanism to eliminate cells during metabolic stress to the advantage of a multicellular organism.


Assuntos
Astrócitos/metabolismo , Linhagem da Célula , Hexoquinase/metabolismo , Mitocôndrias/enzimologia , Fosfoproteínas/metabolismo , Animais , Proteínas Reguladoras de Apoptose , Catálise , Ratos
8.
J Cereb Blood Flow Metab ; 32(2): 213-31, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22086195

RESUMO

One of the hallmarks of stroke pathophysiology is the widespread death of many different types of brain cells. As our understanding of the complex disease that is stroke has grown, it is now generally accepted that various different mechanisms can result in cell damage and eventual death. A plethora of techniques is available to identify various pathological features of cell death in stroke; each has its own drawbacks and pitfalls, and most are unable to distinguish between different types of cell death, which partially explains the widespread misuse of many terms. The purpose of this review is to summarize the standard histopathological and immunohistochemical techniques used to identify various pathological features of stroke. We then discuss how these methods should be properly interpreted on the basis of what they are showing, as well as advantages and disadvantages that require consideration. As there is much interest in the visualization of stroke using noninvasive imaging strategies, we also specifically discuss how these techniques can be interpreted within the context of cell death.


Assuntos
Isquemia Encefálica/patologia , Encéfalo/patologia , Morte Celular , Acidente Vascular Cerebral/patologia , Animais , Humanos , Imuno-Histoquímica/métodos , Imageamento por Ressonância Magnética/métodos , Microscopia/métodos
9.
J Neurosci ; 30(9): 3419-31, 2010 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-20203201

RESUMO

Rearrangement of the actin cytoskeleton is essential for dynamic cellular processes. Decreased actin turnover and rigidity of cytoskeletal structures have been associated with aging and cell death. Gelsolin is a Ca(2+)-activated actin-severing protein that is widely expressed throughout the adult mammalian brain. Here, we used gelsolin-deficient (Gsn(-/-)) mice as a model system for actin filament stabilization. In Gsn(-/-) mice, emigration of newly generated cells from the subventricular zone into the olfactory bulb was slowed. In vitro, gelsolin deficiency did not affect proliferation or neuronal differentiation of adult neural progenitors cells (NPCs) but resulted in retarded migration. Surprisingly, hippocampal neurogenesis was robustly induced by gelsolin deficiency. The ability of NPCs to intrinsically sense excitatory activity and thereby implement coupling between network activity and neurogenesis has recently been established. Depolarization-induced [Ca(2+)](i) increases and exocytotic neurotransmitter release were enhanced in Gsn(-/-) synaptosomes. Importantly, treatment of Gsn(-/-) synaptosomes with mycotoxin cytochalasin D, which, like gelsolin, produces actin disassembly, decreased enhanced Ca(2+) influx and subsequent exocytotic norepinephrine release to wild-type levels. Similarly, depolarization-induced glutamate release from Gsn(-/-) brain slices was increased. Furthermore, increased hippocampal neurogenesis in Gsn(-/-) mice was associated with a special microenvironment characterized by enhanced density of perfused vessels, increased regional cerebral blood flow, and increased endothelial nitric oxide synthase (NOS-III) expression in hippocampus. Together, reduced filamentous actin turnover in presynaptic terminals causes increased Ca(2+) influx and, subsequently, elevated exocytotic neurotransmitter release acting on neural progenitors. Increased neurogenesis in Gsn(-/-) hippocampus is associated with a special vascular niche for neurogenesis.


Assuntos
Citoesqueleto de Actina/metabolismo , Gelsolina/genética , Hipocampo/metabolismo , Neurogênese/fisiologia , Bulbo Olfatório/metabolismo , Células-Tronco/metabolismo , Citoesqueleto de Actina/ultraestrutura , Animais , Sinalização do Cálcio/fisiologia , Movimento Celular/fisiologia , Circulação Cerebrovascular/fisiologia , Citocalasina D/farmacologia , Hipocampo/citologia , Ventrículos Laterais/citologia , Potenciais da Membrana/fisiologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neurônios/metabolismo , Neurônios/ultraestrutura , Neurotoxinas/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Norepinefrina/metabolismo , Inibidores da Síntese de Ácido Nucleico/farmacologia , Bulbo Olfatório/citologia , Técnicas de Cultura de Órgãos , Terminações Pré-Sinápticas/metabolismo , Células-Tronco/ultraestrutura , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/metabolismo
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