Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

There is no treatment for Charcot-Marie-Tooth disease 1A (CMT1A), but ascorbic acid (AA) is efficacious in the transgenic mouse model. Thus, a clinical trial of AA in CMT1A is warranted. The CMT-TRIAAL is a phase III randomized, double-blind, placebo-controlled study involving 222 CMT1A adults from eight Italian centers. Eligible for the study are symptomatic adults with genetically confirmed CMT1A. Treatment consists of 2-year oral AA (1500mg/day) or placebo. The primary trial endpoint is an improvement in CMT Neuropathy Score. Secondary efficacy endpoints are changes in distal arm and leg maximum voluntary isometric contraction; 10m timed walking; 9-hole-peg test; overall neuropathy limitations scale; pain and fatigue visual analog scales; health-related quality of life (SF-36); and electrophysiology. Clinical-electrophysiological assessments are performed at baseline and every 6 months thereafter. In consenting patients from three centers, skin biopsy is performed to evaluate PMP22 expression. The study will last 34 months, starting from March 2006.
 ...
PMID:A multicenter, randomized, double-blind, placebo-controlled trial of long-term ascorbic acid treatment in Charcot-Marie-Tooth disease type 1A (CMT-TRIAAL): the study protocol [EudraCT no.: 2006-000032-27]. 1702 75

A secondary cementation hip stem (Cement Injection Stem; Aesculap, Tuttlingen, Germany) was designed to reduce the risk of fat embolism, and achieve precise implant position and high-quality cement mantle. A validated long-term in vitro simulation was carried out that replicated 24 years of activity of a very demanding patient. Inducible and permanent micromotions were monitored. The cement mantle was sectioned and inspected for signs of fatigue damage. The stem-cement interface was inspected for fretting. Results were compared against previously published results for a conventionally implanted stem with comparable design (Centrament; Aesculap) from which this project was derived. Comparable micromotions were found (slightly larger proximally, in correspondence to the precured centralizer). No sign of fretting was observed. All fatigue damage indicators were comparable or significantly better than those for the conventionally implanted stem. The few cement cracks found were mainly localized in proximity of a proximal drainage hole. It is foreseen that when this detail is optimized, long-term endurance will further improve.
 ...
PMID:In vitro long-term fatigue endurance of the secondary "Cement Injection Stem" hip prosthesis. 1753 56

This study employed both mechanical testing and finite element analysis to compare the stiffness variations among different intramedullary nail constructs used in the treatment of distal femoral fractures. Compressive and torsional experiments were conducted on a transversely, as well as an obliquely fractured sawbone femur restored with the retrograde intramedullary nail. Corresponding finite element models were established to evaluate the stress distributions around screw holes. The results showed that a perifracture screw could increase stiffness by 40% for the obliquely fractured femur, but that it played an insignificant role in stiffness improvement for the transverse fracture groups. Moreover, compared to proximal-screw fixation, distal-screw fixation could improve construct stiffness by 20%. The absence of one of the two distal screws would increase the screw-hole stress by 70%. Therefore, the distal screw around the metaphyseal region has a more important stabilizing effect in the femur-nail construct than does the proximal screw. A twisting stress pattern occurs on the unused screw holes of the metaphyseal region and induces a higher risk for fatigue fracture. The locking screw at the fracture site would be most effective only if it passed through the fracture gap to integrate the separated femoral pieces.
 ...
PMID:Biomechanical analysis of retrograde intramedullary nail fixation in distal femoral fractures. 1872 26

The design of a post and core restoration is a trade-off between a series of requirements to achieve stability of the post itself, the surrounding root dentine and the joint between tooth and post, while maintaining a sufficient apical seal of the remaining root canal filling. Post and core restoration systems come in a variety of different designs and dimensions, where each has its specific strength and weakness. With the exception of threaded versions, posts normally rely on either chemical and/or frictional locking between the post and the remaining root. Failure due to fatigue of the joint or root fracture due to overloading of the dentine is a frequent failure mode, especially for posts anchoring removable prostheses. Perforation of the root in an attempt to maximize the post length is a main cause for failure, too. A new design is proposed which uses a short but large diameter post. The risk of decementation is reduced by positive locking. A cavity with an undercut is prepared into the root, into which the post is fitted. Once joined, the post cannot be separated from the tooth without destruction of either the root or the post. The principle of the new design uses preparation tools and a post which is spread at the bottom. A cylindrically prepared hole is re-shaped to a defined inverse taper with the wider diameter at the bottom of the hole. A cylindrical post is inserted and spread at the bottom to a matching shape after placement. A first in vitro test of the stability showed that the positive locking provides at least as good extraction resistance as conventional post without the critical reliance on the luting/bonding agent.
 ...
PMID:A new design for post and core restorations implementing positive locking. 1884 64

The purpose of this study is to determine if a biomechanical difference exists in dynamic stiffness, fatigue life, and fracture site displacement by comparing three cephalomedullary reconstruction nails. An examination was made of the Biomet Uniflex reconstruction nail, the Biomet Vector nail, and the Stryker Howmedica Long Gamma nail in the fixation of an unstable subtrochanteric femur fracture model, using a synthetic bone model. Mean stiffness for each nail was initially determined in control specimens (i.e. no fracture and no instrumentation). The nail stiffness values were 1764.0 N/mm (controls), 373.61 N/mm (Uniflex), 294.27 N/mm (vector), and 656.36 N/mm (Gamma). The Gamma was statistically stiffer than the Uniflex and Vector (p < 0.002). Mean fatigue life measurements were: Uniflex at 52,891 cycles, failing at the most distal of the proximal two screw holes; Vector at 45,344 cycles, failing in the nail at the level of the fracture site; Gamma at 88,748 cycles failing at the lag screw hole. The p value between the Gamma and Vector was less than 0.01 and between Gamma and Uniflex was less than 0.05. The mean maximal axial displacement at the fracture site was 2.448 mm, 2.305 mm, and 0.790 mm for the Uniflex, Vector and Gamma, respectively. The p value between the Gamma and the other nails was < 0.01. The mean maximal transverse displacement at the fracture site was 1.223 mm, 1.197 mm, and 0.280 mm respectively. The p value between the Long Gamma and the other two nails was < 0.01. In conclusion, the Long Gamma nail demonstrated statistically significant fixation superiority in stiffness, resistance to fatigue, and fracture site displacement compared to the Uniflex and Vector nails. This biomechanical information may aid in choosing implants for fixation of unstable, subtrochanteric femur fractures.
 ...
PMID:Biomechanical comparison of three second-generation reconstruction nails in an unstable subtrochanteric femur fracture model. 1893 12

This study demonstrates the characterization of proton spot scanning on a Li target assembly for accelerator-based BNCT from the viewpoint of heat removal and material strength. These characteristics are investigated as to their dependence on the Li target thickness, considering that the Cu backing plate has more suitable heat removal properties than Li. Two situations are considered in this paper, i.e. the cyclic operation of the spot scanning, and a stalled spot scanning cycle where the proton beam stays focused on a single position on the Li target. It was found that the maximum of the Li temperature and the strain of the Cu backing increase as the cycle period increases. A cycle period less than 120 ms (over 8.3 Hz of frequency) enables the Li temperature to be kept below 150 degrees C and a cycle of less than 115 ms (8.7 Hz) keeps the Cu strain below the critical value for a 230 microm thick Li target, though the values are evaluated conservatively. Against expectation, the Li temperature and Cu strain are larger for a 100 microm thick target than for a 230 microm target. The required cycle period in this case is 23 ms (43 Hz) for maintaining a reasonable Li temperature and 9 ms (110 Hz) to prevent Cu fatigue fracture. For a stall in the spot scanning cycle, the Cu temperature increases as the beam shutdown time increases. The time for Cu to reach its melting point is estimated to be 4.2 ms at the surface, 20 ms at 1mm depth, for both of 100 and 230 microm thick targets. At least 34 ms is estimated to be enough to make a hole on Cu backing plate. A beam shutdown mechanism with a response time of about 20 ms is therefore required.
 ...
PMID:Characteristics of proton beam scanning dependent on Li target thickness from the viewpoint of heat removal and material strength for accelerator-based BNCT. 1904 35

This study aims at developing a femoral stem which maintains appropriate mechanical properties for clinical use and provides enough medullary space for revascularization. Hollow and drilled stems were designed to gain sufficient medullary space. Three-dimensional finite element models of the hollow stems were built including the hollow parameters of different wall thicknesses, bore depths and transverse hole patterns. The effects of these parameters on stress under load bearing were investigated. The results indicated that the effects of thickness on the stem depended on their location along the stem. The hollow depth should be designed as deep as possible to ensure a smooth change of cross-sectional area and avoid unexpected stress concentrations. The transverse hole pattern must be arranged very carefully to avoid high stress concentrations. Then the proper parameters of hollow stem were determined. Through the above processes, the appropriate shape of femoral stem for medullary revascularization was determined as a hollow structure with gradually changing thickness and a distinct hole pattern. Fatigue tests were conducted on three prototypes, which all three prototypes passed. The finite element models and design processes were therefore proved useful for our purpose.
 ...
PMID:Design and test of hip stem for medullary revascularization. 1958 Nov 19

Vertebroplasty (VP) and balloon kyphoplasty (BKP) are now widely used for treating patients in whom the pain due to vertebral compression fractures is severe and has proved to be refractory to conservative treatment. These procedures involve percutaneous delivery of a bolus of an injectable bone cement either directly to the fractured vertebral body, VB (VP) or to a void created in it by an inflatable bone tamp (BKP). Thus, the cement is a vital component of both procedures. In the vast majority of VPs and BKPs, a poly(methyl methacrylate) (PMMA) bone cement is used. This material has many shortcomings, notably lack of bioactivity and very limited resorbability. Thus, there is room for alternative cements. We report here on two variants of a novel, bioactive, Al-free, Zn-based glass polyalkenoate cement (Zn-GPC), and how their properties compare to those of an injectable PMMA bone cement (SIMPL) that is widely used in VP and BKP. The properties determined were injectability, radiopacity, uniaxial compressive strength, and biaxial flexural modulus. In addition, we compared the compression fatigue lives of a validated synthetic osteoporotic VB model (a polyurethane foam cube with an 8 mm-diameter through-thickness cylindrical hole), at 0-2300 N and 3 Hz, when the hole was filled with each of the three cements. A critical review of the results suggests that the performance of each of the Zn-GPCs is comparable to that of SIMPL; thus, the former cements merit further study with a view to being alternatives to an injectable PMMA cement for use in VP and BKP.
 ...
PMID:Evaluation of two novel aluminum-free, zinc-based glass polyalkenoate cements as alternatives to PMMA bone cement for use in vertebroplasty and balloon kyphoplasty. 1965 32

An atrial septal defect (ASD) is a hole in the atrium of the heart. There are 3 types of ASDs; sinus venosus (high in the atrial septum), secundum ASD (middle of septum), and ostium primum (low in the septum). The most common ASD is a secundum ASD. Secundum ASDs are caused by a failure of the atrial septum to close completely during the development of the heart. The most common reported symptoms are fatigue and shortness of breath. Most patients are found to have an ASD after evaluation for a murmur. All ASDs used to be repaired by open heart surgery. However, with advances in the cardiac catheterization lab and development of new devices, some secundum ASDs are able to be closed in the catheterization lab by an interventional cardiologist. There are various types of devices that may be used for closure of an ASD in the cardiac catheterization laboratory. This paper will address 2 of the devices most commonly used. Anticoagulation therapy will need to be followed for approximately 6 months and echocardiograms will need to be obtained at follow-up visits. Nurses have an important role in preparing and teaching the patient and family about the ASD closure procedure and follow-up care.
 ...
PMID:Atrial septal defect devices used in the cardiac catheterization laboratory. 1973 65

A round of golf lasts approximately 4 h, during which time homeostasis could be challenged through either hypoglycemia or hypohydration. This might result in impaired motor skill or cognitive performance. Given the high cognitive demand of putting and the potential fatiguing effects from prolonged walking, the combination of a caffeine and carbohydrate drink could be beneficial in offsetting hypoglycemia and hypohydration. This study used a laboratory-simulated round of golf to examine the effect of an isotonic carbohydrate and caffeine sports drink on putting performance during a round of golf. After institutional ethics approval, 20 male golfers (mean +/- standard deviation: age 23 +/- 4 years, stature 176.4 +/- 5.6 cm, mass 72.8 +/- 17.4 kg, handicap 15 +/- 4, daily caffeine consumption 157.3 +/- 47.2 mg) consumed either an isotonic sports drink containing caffeine (6.4 g carbohydrate and 16 mg caffeine per 100 mL) or a no-energy, flavour-matched placebo drink in a double-blind, randomized, counter-balanced crossover design . Drinks were consumed preround (5 mL.kg-1 body mass (BM)) and at holes 6 and 12 (2.5 mL.kg-1 BM). Participants therefore consumed 1.6 mg.kg-1 BM of caffeine and 0.64 g.kg-1 BM of carbohydrate throughout the trial. Five and 2 m putting performance were assessed at each hole. Self-rated mood assessments were carried out every third hole. Putting performance over 5 m and 2 m and self-rated scores for alertness and relaxation showed a main effect for drink (p < 0.05). Ratings of mental fatigue and tiredness significantly increased during the round (p < 0.001). In experienced golfers, the consumption of an isotonic carbohydrate sports drink containing caffeine prior to and during a round of golf improved putting performance and increased feelings of alertness.
 ...
PMID:The effect of a carbohydrate-caffeine sports drink on simulated golf performance. 1976 4


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>