排序方式: 共有40条查询结果,搜索用时 31 毫秒
11.
Wall BT Dirks ML Verdijk LB Snijders T Hansen D Vranckx P Burd NA Dendale P van Loon LJ 《American journal of physiology. Endocrinology and metabolism》2012,303(5):E614-E623
Physical activity is required to attenuate the loss of skeletal muscle mass with aging. Short periods of muscle disuse, due to sickness or hospitalization, reduce muscle protein synthesis rates, resulting in rapid muscle loss. The present study investigates the capacity of neuromuscular electrical stimulation (NMES) to increase in vivo skeletal muscle protein synthesis rates in older type 2 diabetes patients. Six elderly type 2 diabetic men (70 ± 2 yr) were subjected to 60 min of one-legged NMES. Continuous infusions with l-[ring-(13)C(6)]phenylalanine were applied, with blood and muscle samples being collected regularly to assess muscle protein synthesis rates in both the stimulated (STIM) and nonstimulated control (CON) leg during 4 h of recovery after NMES. Furthermore, mRNA expression of key genes implicated in the regulation of muscle mass were measured over time in the STIM and CON leg. Muscle protein synthesis rates were greater in the STIM compared with the CON leg during recovery from NMES (0.057 ± 0.008 vs. 0.045 ± 0.008%/h, respectively, P < 0.01). Skeletal muscle myostatin mRNA expression in the STIM leg tended to increase immediately following NMES compared with the CON leg (1.63- vs. 1.00-fold, respectively, P = 0.07) but strongly declined after 2 and 4 h of recovery in the STIM leg only. In conclusion, this is the first study to show that NMES directly stimulates skeletal muscle protein synthesis rates in vivo in humans. NMES likely represents an effective interventional strategy to attenuate muscle loss in elderly individuals during bed rest and/or in other disuse states. 相似文献
12.
13.
Magnetic resonance tracking of dendritic cells in melanoma patients for monitoring of cellular therapy 总被引:13,自引:0,他引:13
de Vries IJ Lesterhuis WJ Barentsz JO Verdijk P van Krieken JH Boerman OC Oyen WJ Bonenkamp JJ Boezeman JB Adema GJ Bulte JW Scheenen TW Punt CJ Heerschap A Figdor CG 《Nature biotechnology》2005,23(11):1407-1413
The success of cellular therapies will depend in part on accurate delivery of cells to target organs. In dendritic cell therapy, in particular, delivery and subsequent migration of cells to regional lymph nodes is essential for effective stimulation of the immune system. We show here that in vivo magnetic resonance tracking of magnetically labeled cells is feasible in humans for detecting very low numbers of dendritic cells in conjunction with detailed anatomical information. Autologous dendritic cells were labeled with a clinical superparamagnetic iron oxide formulation or (111)In-oxine and were co-injected intranodally in melanoma patients under ultrasound guidance. In contrast to scintigraphic imaging, magnetic resonance imaging (MRI) allowed assessment of the accuracy of dendritic cell delivery and of inter- and intra-nodal cell migration patterns. MRI cell tracking using iron oxides appears clinically safe and well suited to monitor cellular therapy in humans. 相似文献
14.
The effects of high-frequency initial pulses (HFIP) and posttetanic potentiation on mechanical power output during concentric contractions were examined in the in situ medial gastrocnemius of the rat with an intact origin on the femur and blood supply. Stimulation of the muscle was performed via the severed sciatic nerve. In the experiments, HFIP or the potentiating tetanus was followed by a stimulation of 80, 120, or 200 Hz. The results showed that both HFIP and the tetanus increased power output at high contraction velocities (>75 mm/s) when followed by a train of 80 or 120 Hz (200 Hz resulted in no effects). Mechanical power output was increased maximally by HFIP to 120 and 168% by the tetanus. Furthermore, when HFIP or the tetanus were followed by a train of 80 Hz, the peak power in the power-velocity curve tended to be shifted to a higher velocity. 相似文献
15.
Metin BÜLBÜL Olcay HİSAR Şükrü BEYDEMİR Mehmet ÇİFTÇİ Ö. İrfan KÜFREVIOĞLU 《Journal of enzyme inhibition and medicinal chemistry》2013,28(4):371-375
The in vitro and in vivo inhibitory effects of 5-(3α, 12α-dihydroxy-5-β-cholanamido)-1,3,4-thiadiazole-2-sulfonamide (1), 5-(3α, 7α, 12α-trihydroxy-5-β-cholanamido)-1,3,4-thiadiazole-2-sulfonamide (2), 5-(3α, 7α, 12α-triacetoxy-5-β-cholanamido)-1,3,4-thiadiazole-2-sulfonamide (3) and acetazolamide on rainbow trout (Oncorhynchus mykiss) (RT) erythrocyte carbonic anhydrase (CA) were investigated. The RT erythrocyte CA was obtained by affinity chromatography with a yield of 20.9%, a specific activity of 422.5?EU/mg protein and a purification of 222.4-fold. The purity of the enzyme was confirmed by SDS-PAGE. Inhibitory effects of the sulfonamides and acetazolamide on the RT erythrocyte CA were determined using the CO2-Hydratase method in vitro and in vivo studies. From in vitro studies, it was found that all the compounds inhibited CA. The obtained I50 value for the sulfonamides (1), (2) and (3) and acetazolamide were 0.83, 0.049, 0.82 and 0.052?μM, respectively. From in vivo studies, it was observed that CA was inhibited by the sulfonamides (1), (2) and (3) and acetazolamide. 相似文献
16.
Verdijk LB Koopman R Schaart G Meijer K Savelberg HH van Loon LJ 《American journal of physiology. Endocrinology and metabolism》2007,292(1):E151-E157
Satellite cells (SC) are essential for skeletal muscle growth and repair. Because sarcopenia is associated with type II muscle fiber atrophy, we hypothesized that SC content is specifically reduced in the type II fibers in the elderly. A total of eight elderly (E; 76 +/- 1 yr) and eight young (Y; 20 +/- 1 yr) healthy males were selected. Muscle biopsies were collected from the vastus lateralis in both legs. ATPase staining and a pax7-antibody were used to determine fiber type-specific SC content (i.e., pax7-positive SC) on serial muscle cross sections. In contrast to the type I fibers, the proportion and mean cross-sectional area of the type II fibers were substantially reduced in E vs. Y. The number of SC per type I fiber was similar in E and Y. However, the number of SC per type II fiber was substantially lower in E vs. Y (0.044 +/- 0.003 vs. 0.080 +/- 0.007; P < 0.01). In addition, in the type II fibers, the number of SC relative to the total number of nuclei and the number of SC per fiber area were also significantly lower in E. This study is the first to show type II fiber atrophy in the elderly to be associated with a fiber type-specific decline in SC content. The latter is evident when SC content is expressed per fiber or per fiber area. The decline in SC content might be an important factor in the etiology of type II muscle fiber atrophy, which accompanies the loss of skeletal muscle with aging. 相似文献
17.
J M Raats J B Henderik M Verdijk F L van Oort W L Gerards F C Ramaekers H Bloemendal 《European journal of cell biology》1991,56(1):84-103
Using a vimentin-free expression system we were able to demonstrate that the carboxy terminus of desmin is necessary for filament assembly in the living cell. Desmin subunits missing only 4 carboxy-terminal residues of their rod domain are incapable of homopolymeric filament assembly. Moreover, even single amino acid substitutions in the conserved carboxy-terminal part of the rod domain prevent desmin subunits from homopolymeric filament assembly. Desmin subunits missing 18 or more carboxy-terminal residues of their rod domain (including the complete conserved carboxy-terminal region) are unstable in cells devoid of intact type III intermediate filaments (IFs). Interaction with an intact type III IF, however, stabilizes these mutated desmin subunits. Expression of a desmin subunit missing both its non-helical end domains in vimentin-containing cells disrupts the endogenous vimentin network completely. 相似文献
18.
Lack of geographic variation in anonymous nuclear polymorphisms in the American oyster, Crassostrea virginica 总被引:1,自引:0,他引:1
Comparing geographic variation of noncoding nuclear DNA polymorphisms,
which presumably are neutral to natural selection, with geographic
variation of allozymes is potentially a good way to detect the effects of
selection on allozyme polymorphisms. A previous study of four anonymous
nuclear markers in the American oyster, Crassostrea virginica, found
dramatic differences in allele frequency between the Gulf of Mexico and the
Atlantic Ocean. In contrast, 14 allozyme polymorphisms were fairly uniform
in frequency between the two areas. This led to the conclusion that all of
the allozyme polymorphisms were kept uniform in frequency by balancing
selection. To test the robustness of this pattern, six additional anonymous
nuclear DNA polymorphisms were surveyed in oysters from Panacea, Fla, and
Charleston, S.C. on the Gulf and Atlantic coasts, respectively. Unlike the
previously studied DNA markers, the six DNA polymorphisms examined here
show geographic variation that is not significantly greater than that of
allozymes. The reason for the discrepancy between the two sets of DNA
polymorphisms is unclear.
相似文献
19.
James L Crainey Túllio RR da Silva Fernando Encinas Michel A Marín Ana Carolina P Vicente Sérgio LB Luz 《Memórias do Instituto Oswaldo Cruz》2016,111(1):79-81
We report here the first complete mitochondria genome of Onchocerca
volvulus from a focus outside of Africa. An O. volvulus
mitogenome from the Brazilian Amazonia focus was obtained using a combination of
high-throughput and Sanger sequencing technologies. Comparisons made between this
mitochondrial genome and publicly available mitochondrial sequences identified 46
variant nucleotide positions and suggested that our Brazilian mitogenome is more
closely related to Cameroon-origin mitochondria than West African-origin
mitochondria. As well as providing insights into the origins of Latin American
onchocerciasis, the Brazilian Amazonia focus mitogenome may also have value as an
epidemiological resource. 相似文献
20.
In wetlands the effects of fire on vegetation dynamics are somewhat uncertain. A change detection analysis in the herbaceous wetlands of KwaMbonambi, South Africa, which were subject to frequent fires, revealed that in 1937 the study area comprised grassland (69%), herbaceous wetland (25%), indigenous swamp forest (4%) and tree plantations (1%). However, by 1970, tree plantations occupied 78% of the landscape and grasslands and herbaceous wetlands had declined to 9% and 6%, respectively, whereas indigenous swamp forest had increased to 6%. By 2009 tree plantations had been removed from the wetland areas. Despite this opportunity for herbaceous wetlands to recover their historical extent, they decreased to only 2%, mostly changing to indigenous swamp forest or to an herbaceous/fern (Stenochlaena tenuifolia)/woodland mosaic. Fire records showed suppression of fire to be an important contributing factor, particularly in wetlands that had been disturbed by tree plantations, although subsequently removed. A pilot burning experiment revealed that S. tenuifolia did not inhibit fire. It is therefore practicable to increase fire frequency to prevent the mosaic developing into forest. A conceptual model of the influence of fire regime on wetland vegetation type is presented and priorities for further research on wetlands and fire are recommended. 相似文献