排序方式: 共有101条查询结果,搜索用时 109 毫秒
51.
Cerebellar Purkinje neurons in vivo exhibit high frequency and multi-spike action potentials with transient (INaT), resurgent (INaR) and persistent (INaP) Na+ currents arising from voltage-gated Na+ channels, which play important roles in shaping the action potentials and electrical activity of these cells. However, little is known about Na+ channel expression in cultured Purkinje neurons despite the use of in vitro approaches to study these cells. Therefore, GFP-expressing Purkinje neurons isolated from transgenic mice were analysed after four weeks in culture, when, coincident with distinct axonal and dendritic morphologies, cultured Purkinje neurons exhibited dendrite-specific MAP2 expression characteristic of polarized neurons. In cell-attached patch clamp recordings, Na+ currents occurred at significantly higher frequencies and amplitudes in patches from the soma and axon than from dendrites, similar to the polarized distribution observed in vivo. INaT, INaR and INaP Na+ currents with properties similar to those observed in acutely isolated Purkinje neurons were detected in nucleated outside-out patches from cultured Purkinje cells. RT-PCR analysis detected Nav1.1, Nav1.2 and Nav1.6, but not Nav1.3, Nav1.4, Nav 1.5 or Nav1.8 Na+ channel alpha subunit gene expression in cultured Purkinje neurons, as observed in vivo. Together, the results indicate that key aspects of Na+ channel expression in mature Purkinje neurons in vivo occur in vitro. 相似文献
52.
Gianmarco M Balestra Egbert G Mik Otto Eerbeek Patricia AC Specht Willem J van der Laarse Coert J Zuurbier 《Respiratory research》2015,16(1)
Background
The leading cause of mortality due to pulmonary arterial hypertension (PAH) is failure of the cardiac right ventricle. It has long been hypothesized that during the development of chronic cardiac failure the heart becomes energy deprived, possibly due to shortage of oxygen at the level of cardiomyocyte mitochondria. However, direct evaluation of oxygen tension levels within the in vivo right ventricle during PAH is currently lacking. Here we directly evaluated this hypothesis by using a recently reported technique of oxygen-dependent quenching of delayed fluorescence of mitochondrial protoprophyrin IX, to determine the distribution of mitochondrial oxygen tension (mitoPO2) within the right ventricle (RV) subjected to progressive PAH.Methods
PAH was induced through a single injection of monocrotaline (MCT). Control (saline-injected), compensated RV hypertrophy (30 mg/kg MCT; MCT30), and RV failure (60 mg/kg MCT; MCT60) rats were compared 4 wk after treatment. The distribution of mitoPO2 within the RV was determined in mechanically-ventilated, anaesthetized animals, applying different inspired oxygen (FiO2) levels and two increment dosages of dobutamine.Results
MCT60 resulted in RV failure (increased mortality, weight loss, increased lung weight), MCT30 resulted in compensated RV hypertrophy. At 30% or 40% FiO2, necessary to obtain physiological arterial PO2 in the diseased animals, RV failure rats had significantly less mitochondria (15% of total mitochondria) in the 0-20 mmHg mitoPO2 range than hypertrophied RV rats (48%) or control rats (54%). Only when oxygen supply was reduced to 21% FiO2, resulting in low arterial PO2 for the MCT60 animals, or when oxygen demand increased with high dose dobutamine, the number of failing RV mitochondria with low oxygen became similar to control RV. In addition, metabolic enzyme analysis revealed similar mitochondrial mass, increased glycolytic hexokinase activity following MCT, with increased lactate dehydrogenase activity only in compensated hypertrophied RV.Conclusions
Our novel observation of increased mitochondrial oxygenation suggests down-regulation of in vivo mitochondrial oxygen consumption, in the absence of hypoxia, with transition towards right ventricular failure induced by pulmonary arterial hypertension. 相似文献53.
T Williams E Walz AR Lane M Pebole AC Hackney 《Biology of sport / Institute of Sport》2015,32(3):193-198
This study assessed the influence of estrogen (E2) on muscle damage biomarkers [skeletal muscle - creatine kinase (CK); cardiac muscle - CK-MB] responses to prolonged aerobic exercise. Eumenorrheic women (n=10) who were physically active completed two 60-minute treadmill running sessions at ∼60-65% maximal intensity during low E2 (midfollicular menstrual phase) and high E2 (midluteal menstrual phase) hormonal conditions. Blood samples were collected prior to exercise (following supine rest), immediately post-, 30 min post-, and 24 hours post-exercise to determine changes in muscle biomarkers. Resting blood samples confirmed appropriate E2 hormonal levels Total CK concentrations increased following exercise and at 24 hours post-exercise were higher in the midfollicular low E2 phase (p<0.001). However, CK-MB concentrations were unaffected by E2 level or exercise (p=0.442) resulting in the ratio of CK-MB to total CK being consistently low in subject responses (i.e., indicative of skeletal muscle damage). Elevated E2 levels reduce the CK responses of skeletal muscle, but had no effect on CK-MB responses following prolonged aerobic exercise. These findings support earlier work showing elevated E2 is protective of skeletal muscle from exercise-induced damage associated with prolonged aerobic exercise. 相似文献
54.
Geraldine AC Lim Erica G Jewell Xi Li Timothy A Erwin Christopher Love Jacqueline Batley German Spangenberg David Edwards 《BMC plant biology》2007,7(1):40
Background
Molecular genetic maps provide a means to link heritable traits with underlying genome sequence variation. Several genetic maps have been constructed for Brassica species, yet to date, there has been no simple means to compare this information or to associate mapped traits with the genome sequence of the related model plant, Arabidopsis. 相似文献55.
Irene EM Bultink D?rte Hamann Marc A Seelen Margreet H Hart Ben AC Dijkmans Mohamed R Daha Alexandre E Voskuyl 《Arthritis research & therapy》2007,8(6):R183
Infection imposes a serious burden on patients with systemic lupus erythematosus (SLE). The increased infection rate in SLE
patients has been attributed in part to defects of immune defence. Recently, the lectin pathway of complement activation has
also been suggested to play a role in the occurrence of infections in SLE. In previous studies, SLE patients homozygous for
mannose-binding lectin (MBL) variant alleles were at an increased risk of acquiring serious infections in comparison with
patients who were heterozygous or homozygous for the normal allele. This association suggests a correlation between functional
MBL level and occurrence of infections in SLE patients. We therefore investigated the biological activity of MBL and its relationship
with the occurrence of infections in patients with SLE. Demographic and clinical data were collected in 103 patients with
SLE. Functional MBL serum levels and MBL-induced C4 deposition were measured by enzyme-linked immunosorbent assay using mannan
as coat and an MBL- or C4b-specific monoclonal antibody. The complete MBL-dependent pathway activity was determined by using
an assay that measures the complete MBL pathway activity in serum, starting with binding of MBL to mannan, and was detected
with a specific monoclonal antibody against C5b-9. Charts were systematically reviewed to obtain information on documented
infections since diagnosis of SLE. Major infections were defined as infections requiring hospital admission and intravenous
administration of antibiotics. In total, 115 infections since diagnosis of lupus, including 42 major infections, were documented
in the 103 SLE patients (mean age 41 ± 13 years, mean disease duration 7 ± 4 years). The percentage of SLE patients with severe
MBL deficiency was similar to that in 100 healthy controls: 13% versus 14%, respectively. Although deposition of C4 to mannan
and MBL pathway activity were reduced in 21% and 43% of 103 SLE patients, respectively, neither functional MBL serum levels
nor MBL pathway activity was associated with infections or major infections in regression analyses. In conclusion, SLE patients
frequently suffer from infections, but deficiency of functional MBL does not confer additional risk. 相似文献
56.
Data from population- and clinic-based epidemiologic studies of rheumatoid arthritis patients suggest that individuals with
rheumatoid arthritis are at risk for developing clinically evident congestive heart failure. Many established risk factors
for congestive heart failure are over-represented in rheumatoid arthritis and likely account for some of the increased risk
observed. In particular, data from animal models of cytokine-induced congestive heart failure have implicated the same inflammatory
cytokines produced in abundance by rheumatoid synovium as the driving force behind maladaptive processes in the myocardium
leading to congestive heart failure. At present, however, the direct effects of inflammatory cytokines (and rheumatoid arthritis
therapies) on the myocardia of rheumatoid arthritis patients are incompletely understood. 相似文献
57.
Characterization of bovine homologues of granulysin and NK-lysin 总被引:6,自引:0,他引:6
Endsley JJ Furrer JL Endsley MA McIntosh MA Maue AC Waters WR Lee DR Estes DM 《Journal of immunology (Baltimore, Md. : 1950)》2004,173(4):2607-2614
Granulysin and NK-lysin are antimicrobial proteins found in the granules of human and swine cytotoxic lymphocytes. A murine counterpart to granulysin has not been identified to date, indicating the importance of additional models to fully characterize the role of granulysin-like molecules in the immune response to infectious disease. Two partial nucleotide sequences corresponding to the complete functional domain of granulysin and NK-lysin were amplified from bovine PBMC mRNA. Following stimulation with phorbol ester and calcium ionophore, expression of the bovine gene was detected in CD3(+) T cells, CD4(+) T cells, CD8(+) T cells, WC1(+) gammadelta T cells, and PBMC depleted of CD3(+) T cells, but was absent in CD21(+) cells and CD14(+) cells. Intracellular flow cytometry and immunoblotting confirmed the presence of protein corresponding to the bovine granulysin homologue in activated T lymphocytes and PBMC. Synthetic human, bovine, and swine peptides corresponding to the C terminus of helix 2 through helix 3 region of granulysin displayed potent antimicrobial activity against Escherichia coli, Salmonella enteritidis, Staphylococcus aureus, and Mycobacterium bovis bacillus Calmette-Guérin. Human and bovine peptides corresponding to helix 2 displayed antimycobacterial activity against M. bovis bacillus Calmette-Guérin. Expression of the bovine gene was detected in laser microscopy-dissected lymph node lesions from an M. bovis-infected animal. The identification of a biologically active bovine homologue to granulysin demonstrates the potential of the bovine model in characterizing the role of granulysin in the immune response to a variety of infectious agents. 相似文献
58.
Determinants of Readiness for Adopting Healthy Lifestyle Behaviors Among Indigenous Adolescents with Type 2 Diabetes in Manitoba,Canada: A Cross‐Sectional Study 下载免费PDF全文
59.
Diversity of PAH-degrading bacteria in an airlift-suspension reactor system for waste-water cleaning
Different samples from a reactor system for the cleaning of an emulsified waste oil containing approximately 1% of different polycyclic aromatic hydrocarbons (PAH) were studied for the diversity of phenanthrene, anthracene, and acenaphthene-metabolizing bacteria. From more than 28 different taxa found in the airlift-suspension reactor, nine were able to mineralize at least one of the PAH, belonging to the genera Bacillus, Mycobacterium, Nocardia, Sphingomonas, Alcaligenes, Pseudomonas, and the Flavobacterium/Cytophaga group. In the sludge from the thickener of the reactor system, a reduced number of metabolically active groups could be detected. The impact of different precultivation substrates on the degradation capability was investigated with five PAH-degrading bacterial strains. Four isolates were influenced by the precultivation substrates, however, one isolate (Alcaligenes-like) as well as the mixture of the five strains showed no changes in their degradation capability. The results indicated a strong impact of the precultivation methods on the composition of bacterial communities and the activity and the degradation characteristics of bacteria with respect to different PAH. 相似文献
60.
Timm Konold A Robin Sayers Amanda Sach Gemma E Bone Steven van Winden Gerald AH Wells Marion M Simmons Michael J Stack Angus Wear Steve AC Hawkins 《BMC veterinary research》2010,6(1):53