417 research outputs found
Lyophilization protects [FeFe]-hydrogenases against O2-induced H-cluster degradation
Nature has developed an impressive repertoire of metal-based enzymes that
perform complex chemical reactions under moderate conditions. Catalysts that
produce molecular hydrogen (H2) are particularly promising for renewable
energy applications. Unfortunately, natural and chemical H2-catalysts are
often irreversibly degraded by molecular oxygen (O2). Here we present a
straightforward procedure based on freeze-drying (lyophilization), that turns
[FeFe]-hydrogenases, which are excellent H2-producers, but typically extremely
O2-sensitive in solution, into enzymes that are fully resistant against O2.
Complete dryness protects and conserves both, the [FeFe]-hydrogenase proteins
and their inorganic active-site cofactor (H-cluster), when exposed to 100% O2
for days. The full H2-formation capacity is restored after solvation of the
lyophilized enzymes. However, even minimal moisturizing re-establishes
O2-sensitivity. The dry [FeFe]-hydrogenase material is superior also for
advanced spectroscopic investigations on the H-cluster reaction mechanism. Our
method provides a convenient way for long-term storage and impacts on
potential biotechnological hydrogen production applications of hydrogenase
enzymes
Supersymmetric Higgs Yukawa Couplings to Bottom Quarks at next-to-next-to-leading Order
The effective bottom Yukawa couplings are analyzed for the minimal
supersymmetric extension of the Standard Model at two-loop accuracy within
SUSY-QCD. They include the resummation of the dominant corrections for large
values of tg(beta). In particular the two-loop SUSY-QCD corrections to the
leading SUSY-QCD and top-induced SUSY-electroweak contributions are addressed.
The residual theoretical uncertainties range at the per-cent level.Comment: 25 pages, 9 figures, added comments and references, typos corrected,
results unchanged, published versio
Sequential loss of myelin proteins during Wallerian degeneration in the human spinal cord
Axons undergo Wallerian degeneration (WD) distal to a point of injury. In the lesioned PNS, WD may be followed by successful axonal regeneration and functional recovery. However, in the lesioned mammalian CNS, there is no significant axonal regeneration. Myelin-associated proteins (MAPs) have been shown to play significant roles in preventing axonal regeneration in the CNS. Since relatively little is known about such events in human CNS pathologies, we performed an immunohistochemical investigation on the temporal changes of four MAPs during WD in post-mortem spinal cords of 22 patients who died 2 days to 30 years after either cerebral infarction or traumatic spinal cord injury. In contrast to experimental studies in rats, the loss of myelin sheaths is greatly delayed in humans and continues slowly over a number of years. However, in agreement with animal data, a sequential loss of myelin proteins was found which was dependent on their location within the myelin sheath. Myelin proteins situated on the peri-axonal membrane were the first to be lost, the time course correlating with the loss of axonal markers. Proteins located within compact myelin or on the outer myelin membrane were still detectable 3 years after injury in degenerating fibre tracts, long after the disappearance of the corresponding axons. The persistence of axon growth-inhibitory proteins such as NOGO-A in degenerating nerve fibre tracts may contribute to the maintenance of an environment that is hostile to axon regeneration, long after the initial injury. The present data highlight the importance of correlating the well documented, lesion-induced changes that take place in controlled laboratory investigations with those that take place in the clinical domai
Rapid Assessment of Age-Related Differences in Standing Balance
As life expectancy continues to rise, in the future there will be an increasing number of older people prone to falling. Accordingly, there is an urgent need for comprehensive testing of older individuals to collect data and to identify possible risk factors for falling. Here we use a low-cost force platform to rapidly assess deficits in balance under various conditions. We tested 21 healthy older adults and 24 young adults during static stance, unidirectional and rotational displacement of their centre of pressure (COP). We found an age-related increase in postural sway during quiet standing and a reduction of maximal COP displacement in unidirectional and rotational displacement tests. Our data show that even low-cost computerized assessment tools allow for the comprehensive testing of balance performance in older subjects
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As life expectancy continues to rise, in the future there will be an increasing number of older people prone to falling. Accordingly, there is an urgent need for comprehensive testing of older individuals to collect data and to identify possible risk factors for falling. Here we use a low-cost force platform to rapidly assess deficits in balance under various conditions. We tested 21 healthy older adults and 24 young adults during static stance, unidirectional and rotational displacement of their centre of pressure (COP). We found an age-related increase in postural sway during quiet standing and a reduction of maximal COP displacement in unidirectional and rotational displacement tests. Our data show that even low-cost computerized assessment tools allow for the comprehensive testing of balance performance in older subjects
Progenitor and stem cells for bone and cartilage regeneration
Research in regenerative medicine is developing at a significantly quick pace. Cell-based bone and
cartilage replacement is an evolving therapy aiming at the treatment of patients who suffer from
limb amputation, damaged tissues and various bone and cartilage-related disorders. Stem cells are
undifferentiated cells with the capability to regenerate into one or more committed cell lineages.
Stem cells isolated from multiple sources have been finding widespread use to advance the field of
tissue repair. The present review gives a comprehensive overview of the developments in stem cells
originating from different tissues and suggests future prospects for functional bone and cartilage
tissue regeneration.The European Network of Excellence EXPERTISSUES (Project No. NMP3-CT-2004-500283), under which this work was carried out, is acknowledged
Cardiovascular safety of nintedanib in subgroups by cardiovascular risk at baseline in the TOMORROW and INPULSIS trials
Nintedanib is a tyrosine kinase inhibitor used to treat idiopathic pulmonary fibrosis (IPF). We investigated the cardiovascular safety of nintedanib using pooled data from the TOMORROW and INPULSIS trials.Cardiovascular events were assessed post hoc in patients with a history of atherosclerotic cardiovascular disease (CVD) and/or one or more cardiovascular risk factors at baseline ("higher cardiovascular risk") and patients with no history of atherosclerotic CVD and no cardiovascular risk factors at baseline ("lower cardiovascular risk").Incidence rates were calculated for 1231 patients (n=723 nintedanib and n=508 placebo), of whom 89.9% had higher cardiovascular risk. Incidence rates of major adverse cardiovascular events were similar in the nintedanib and placebo groups in patients with higher cardiovascular risk (3.88 (95% CI 2.58-5.84) and 3.49 (95% CI 2.10-5.79) per 100 patient-years, respectively) and lower cardiovascular risk (4.78 (95% CI 1.54-14.82) and 5.37 (95% CI 1.73-16.65) per 100 patient-years, respectively). Incidence rates of myocardial infarction in the nintedanib and placebo groups, respectively, were 3.03 (95% CI 1.91-4.81) and 1.16 (95% CI 0.48-2.79) per 100 patient-years in patients with higher cardiovascular risk and 1.59 (95% CI 0.22-11.29) and 1.78 (95% CI 0.25-12.64) per 100 patient-years in patients with lower cardiovascular risk. Incidence rates of other ischaemic heart disease in the nintedanib and placebo groups, respectively, were 1.85 (95% CI 1.02-3.34) and 3.28 (95% CI 1.94-5.54) per 100 patient-years in patients with higher cardiovascular risk and 0 and 1.80 (95% CI 0.25-12.78) per 100 patient-years in patients with lower cardiovascular risk.These data help to establish the cardiovascular safety profile of nintedanib in IPF
A systematic review of the concept and clinical applications of Bone Marrow Aspirate Concentrate in Orthopaedics
INTRODUCTION: Mesenchymal stem cells (MSC's) are believed to have multipotent plasticity with the capability to differentiate along multiple cell lineages such as cartilage, bone, tendon, muscle, and nerve. Such multipotency has the potential to play an important role in the repair and reconstruction of multiple tissues across a number of orthopaedic specialties. Bone marrow and fat are the most abundant and accessible source of MSC's with bone marrow aspirate the most commonly being reported to stimulate healing. METHODS: This review examines the current reported 20 Q2 clinical applications of bone marrow aspirate concentrate and its effectiveness. RESULTS: The published studies reported techniques of collection and preparation of BMAC in addition to its applications in a number of orthopaedic sub-specialities. Studies could be sub-categorised into: techniques of extraction, processing and microscopic examination of BMAC (31), reconstruction of osseous defects/non-union (20), treatment of avascular necrosis (9), repair of cartilage defects (8), treatment of sports injuries and tendon injury/repair (9), injection in regenerative therapy (4), treatment of spine conditions (4) including enhancing postoperative fusion and degenerative disc pathology and orthopaedic oncology (4). A few published studies combined the use of platelet-rich plasma (PRP) with BMAC (4) or compared them in different applications (5). CONCLUSIONS: BMAC has been used in bone, cartilage and tendon injuries with encouraging results
NG2 and phosphacan are present in the astroglial scar after human traumatic spinal cord injury
BACKGROUND: A major class of axon growth-repulsive molecules associated with CNS scar tissue is the family of chondroitin sulphate proteoglycans (CSPGs). Experimental spinal cord injury (SCI) has demonstrated rapid re-expression of CSPGs at and around the lesion site. The pharmacological digestion of CSPGs in such lesion models results in substantially enhanced axonal regeneration and a significant functional recovery. The potential therapeutic relevance of interfering with CSPG expression or function following experimental injuries seems clear, however, the spatio-temporal pattern of expression of individual members of the CSPG family following human spinal cord injury is only poorly defined. In the present correlative investigation, the expression pattern of CSPG family members NG2, neurocan, versican and phosphacan was studied in the human spinal cord. METHODS: An immunohistochemical investigation in post mortem samples of control and lesioned human spinal cords was performed. All patients with traumatic SCI had been clinically diagnosed as having "complete" injuries and presented lesions of the maceration type. RESULTS: In sections from control spinal cord, NG2 immunoreactivity was restricted to stellate-shaped cells corresponding to oligodendrocyte precursor cells. The distribution patterns of phosphacan, neurocan and versican in control human spinal cord parenchyma were similar, with a fine reticular pattern being observed in white matter (but also located in gray matter for phosphacan). Neurocan staining was also associated with blood vessel walls. Furthermore, phosphacan, neurocan and versican were present in the myelin sheaths of ventral and dorsal nerve roots axons. After human SCI, NG2 and phosphacan were both detected in the evolving astroglial scar. Neurocan and versican were detected exclusively in the lesion epicentre, being associated with infiltrating Schwann cells in the myelin sheaths of invading peripheral nerve fibres from lesioned dorsal roots. CONCLUSION: NG2 and phosphacan were both present in the evolving astroglial scar and, therefore, might play an important role in the blockade of successful CNS regeneration. Neurocan and versican, however, were located at the lesion epicentre, associated with Schwann cell myelin on regenerating peripheral nerve fibres, a distribution that was unlikely to contribute to failed CNS axon regeneration. The present data points to the importance of such correlative investigations for demonstrating the clinical relevance of experimental data
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