vendex and Atrophy

We determined the effectiveness of low-volume resistance exercise (EX) for the attenuation of loss of muscle mass and strength during leg immobilization. Men (N = 5) and women (N = 12, age 24 ± 5 years, body mass index 25.4 ± 3.6 kg/m(2)) were divided into two groups: exercise (EX; n = 12) and control (CON; n = 5). Subjects wore a knee brace on one leg that prevented weight bearing for 14 days. Resistance exercise (EX; 80% of maximal) was performed by the immobilized limb every other day. Immobilization induced a significant reduction (P < 0.05) in muscle fiber and thigh cross-sectional area (CSA), isometric knee extensor, and plantarflexor strength in the CON (P < 0.01) but not in the EX group. There were significant losses in triceps surae CSA in the CON and EX groups (P < 0.05), but the losses were greater in CON subjects (P < 0.01). A minimal volume (140 contractions in 14 days) of resistive exercise is an effective countermeasure against immobilization-induced atrophy of the quadriceps femoris but is only partially effective for the triceps surae.

Topics: Anatomy, Cross-Sectional; Atrophy; Diet; Electromyography; Female; Humans; Immobilization; Leg; Magnetic Resonance Imaging; Male; Motor Neurons; Muscle Strength; Muscle, Skeletal; Thigh; Time Factors; Torque; Weight Lifting

Typically, the greater the atrophy of the process, the more extensive and invasive the sinus floor elevation procedure is. This case of a 39-year-old man demonstrates a minimally invasive hydrostatic sinus lift from 1.7-mm height process in the site of lost tooth No. 16. Using a small flap, safe drills for a crestal approach diameter of 2.8 mm, 2 mL of saline solution under pressure of a syringe plunger, and 1 g of particulated bovine xenograft, a 14-mm height and 12-mm width sinus floor elevation was obtained. The implant was placed with a torque of 30 Ncm, and a healing cap was attached. Despite the very difficult conditions, the presented method not only resulted in a very good therapeutic effect but also reduced the number of procedures and time necessary for complete rehabilitation of the patient. The total treatment time to the final crown delivery was 6 months.

Topics: Adult; Animals; Atrophy; Cattle; Dental Implantation, Endosseous; Humans; Male; Maxillary Sinus; Sinus Floor Augmentation; Torque

The aim of this study was to evaluate the clinical outcomes of trans-sinus dental implant placement by use of bone morphogenetic protein 2 (BMP-2) grafting and immediate functional loading by the all-on-4 scheme.. After bone reduction to create the all-on-4 shelf or because of severe maxillary atrophy and prominent sinus anatomy, 10 patients were selected to undergo trans-sinus implant placement and simultaneous BMP-2 sinus floor grafting for immediate provisional loading. Insertion torque was measured upon implant placement. Patients were followed up for at least 1 year after final restoration when either a computed tomography scan or panoramic radiograph was obtained and analyzed for the presence of trans-sinus peri-implant bone. Hounsfield units were recorded mid sinus graft.. Of 19 trans-sinus implants, 18 remained integrated at the 1-year follow-up, for a 5.2% failure rate. All sinus grafts formed bone, with a mean of 460 Hounsfield units. Final fixed prostheses were completed for all 10 patients.. Trans-sinus dental implant placement with BMP-2 grafting to gain anterior-posterior spread for immediate function by use of all-on-4 treatment appears to be a viable alternative to the use of zygomatic implants in the presence of severe maxillary atrophy.

Topics: Atrophy; Bone Density; Bone Morphogenetic Protein 2; Bone Substitutes; Bone Transplantation; Dental Implantation, Endosseous; Dental Implants; Follow-Up Studies; Humans; Immediate Dental Implant Loading; Maxilla; Maxillary Sinus; Nasal Cavity; Osseointegration; Osteogenesis; Radiography, Panoramic; Sinus Floor Augmentation; Tomography, X-Ray Computed; Torque; Treatment Outcome

This study aimed to evaluate the long-term prognosis of immediately loaded fixed full prostheses for the treatment of edentulous patients with extreme bone atrophy in the posterior mandibular region.. Twenty-four edentulous patients with atrophic posterior mandibles were treated by means of a complete prosthesis sustained by both axial and tilted fixtures. The insertion of tilted implants was carefully planned by means of computed tomography scan analysis and measuring width and height of residual bone. Implant type, length, and diameter were chosen, as well as implant angulation, according to the All-on-Four protocol and avoiding the course of the mandibular nerve. The prosthesis was delivered no later than 2 days after implant surgery. Implant survival and prosthesis success were assessed clinically and radiographically up to 42 months of follow-up. Measurement of peri-implant bone loss was based on periapical radiographs after 12 months of loading.. All implants survived and all prostheses were successful at the time of this study reporting. The mean follow-up was 30.1 months with a range of 14 to 44 months. The average peri-implant bone loss was 0.85 mm after 12 months (0.8 mm for tilted implants and 0.9 mm for axial implants). No significant difference in marginal bone loss was observed between axial and tilted implants.. The immediate rehabilitation of patients with extreme atrophic mandibles can be successful with careful planning and particular attention during the surgical placement of the implants, as shown by the excellent outcomes of the present study.

Topics: Adult; Aged; Alveolar Bone Loss; Atrophy; Bone Density; Dental Abutments; Dental Implantation, Endosseous; Dental Implants; Dental Prosthesis Design; Dental Prosthesis, Implant-Supported; Denture Design; Denture, Complete, Immediate; Denture, Complete, Lower; Female; Follow-Up Studies; Humans; Jaw, Edentulous; Longitudinal Studies; Male; Mandible; Middle Aged; Patient Satisfaction; Prognosis; Radiography; Survival Analysis; Torque; Treatment Outcome

We present a technical note and 3 case reports of all-on-4 treatment of highly resorbed maxillas. The use of 4 angled implants, placed at as much as 30 degrees off axis, that engage the lateral nasal wall bone provide high torque fixation for immediate temporization. The technique is proposed as an alternative to sinus grafting and for use with multiple implants or zygomatic implants.

Topics: Aged; Alveolar Bone Loss; Alveolar Process; Atrophy; Biomechanical Phenomena; Bone Resorption; Dental Implantation, Endosseous; Dental Implants; Dental Prosthesis Design; Female; Humans; Maxilla; Maxillary Fractures; Middle Aged; Nasal Cavity; Tooth Avulsion; Torque

Strength decrements observed after extended (4-6 wk) periods of muscle unloading are associated with significant atrophy. Because early (up to 2 wk) strength gains from resistance exercise are related to improved neural recruitment, we hypothesized that the loss of strength resulting from 2 wk of muscle unloading [unilateral lower limb suspension (ULLS)] was due to impaired neural activation of the affected muscle. Blood samples, muscle biopsy specimens, muscle function data, and electromyography (EMG) recordings were analyzed before and after 14 days of muscle unloading. Pre- to postunloading data showed significant (P < or = 0.05) decrements in peak torque and total work performed by knee extensors and flexors. This was coupled with decreased EMG activity, but no change in neuromuscular efficiency (total torque/EMG). Resistance to muscle fatigue was enhanced after ULLS. The 14-day intervention failed to alter the size or fiber type distribution of muscle samples. However, resting plasma cortisol levels were significantly increased after muscle unloading, suggesting an endocrine environment favorable to muscle atrophy. Our data confirm that the diminution in muscle function displayed after 2 wk of unloading is mainly due to neural, rather than contractile, disturbances.

Topics: Adrenocorticotropic Hormone; Adult; Atrophy; Biopsy; Electromyography; Female; Humans; Hydrocortisone; Immobilization; Male; Muscle Contraction; Muscle Fibers, Skeletal; Muscle, Skeletal; Organ Size; Torque; Weight-Bearing

This investigation examined the effects of 4 weeks of non-dominant arm unloading on the functional and structural characteristics of the triceps brachii muscle of six normo-active college-age males (age: 23 +/- 1 years, height: 176 +/- 4 cm, weight: 76 +/- 6 kg). The primary intention of this study was to determine if arm unloading is an effective analogue for simulating the effects of weightlessness on human skeletal muscle. Subjects were tested 2-3 days preceding unloading in a standard arm sling and following removal of the sling. The sling was worn during waking hours to unload the arm. Subjects were allowed to remove the sling during sleep and bathing. Torque production (Nm) during maximal isometric extension at 90 degrees significantly declined (P < 0.05) in response to unloading (53.93 +/- 5.07 to 47.90 +/- 5.92; 12%). There was no significant change (P > 0.05) in the force-velocity attributes of the triceps over the other measured velocities (1.05, 1.57, 2.09, 3.14, 4.19, 5.24 rad.s-1). Cross-sectional muscle area (CSA) of the upper arm was smaller (44.3 +/- 2.7 to 42.4 +/- 2.5 cm2; 4%) following 4 weeks of unloading (P < 0.05). Histochemical analysis of individual muscle fibres demonstrated reductions in fibre CSA of 27 and 18% for type I and type II fibres, respectively. However, these changes were not statistically significant. Electrophoretic analysis of muscle samples revealed a significant increase (40 +/- 7 to 58 +/- 4%, pre- and post-, respectively) in myosin heavy chain (MHC) type II isoforms following unloading. Reductions in type I MHC isoform composition failed to reach statistical significance (P < 0.08). Amplitude of the integrated electromyographic (IEMG) signal during maximal isometric contraction of the long head of the triceps decreased by 21% in response to the 4-week unloading period (P < 0.05). The changes in triceps, muscle structure and function found with arm unloading are similar in magnitude and direction to data obtained from humans following exposure to real and simulated weightlessness. These findings demonstrate that arm unloading produces some of the effects seen in response to weightlessness in muscles of the upper arm and provides potential for an additional model to simulate the effects of microgravity on human skeletal muscle.

Topics: Adult; Arm; Atrophy; Electromyography; Humans; Isometric Contraction; Male; Muscle Fibers, Skeletal; Muscle, Skeletal; Myosin Heavy Chains; Orthotic Devices; Torque; Weight-Bearing; Weightlessness Simulation

This study describes the metabolic, morphologic, neurologic, and functional adaptations observed in the plantar flexors during 8 weeks of lower leg immobilization and 10 weeks of physical therapy following ankle surgery. A combination of magnetic resonance imaging and spectroscopy, isokinetic and isometric muscle testing, and simple functional tests revealed many adaptive changes due to immobilization, including atrophy, loss of muscle strength, reduced central activation, increase in fatigue resistance, and an increase in inorganic phosphate content. After 10 weeks of physical therapy all alterations were reversed, with the exception of a remaining 5.5% deficit in total muscle cross-sectional area.

Topics: Adult; Ankle Injuries; Atrophy; Bed Rest; Casts, Surgical; Fractures, Bone; Humans; Isometric Contraction; Isotonic Contraction; Longitudinal Studies; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Male; Motor Activity; Muscle, Skeletal; Physical Therapy Modalities; Torque; Walking

Twenty-two beagles were divided into two equal groups, and the right hindlimb of each animal was immobilized at 105 degrees of knee flexion by external fixation. After 10 weeks of fixation, the device was removed, allowing free mobility for the following 5 weeks. Each day throughout the 15 weeks, one group received a growth hormone secretagogue (treatment) at a dose of 5 mg/kg, and the other received a lactose placebo (control). At weeks 0, 10, and 15, strength as indicated by maximum isometric extension torque was measured in the right hindlimb, biopsies of the vastus lateralis muscle were taken, and the dogs were weighed. Weekly blood samples were analyzed for insulin-like growth factor-1, blood urea nitrogen, and creatine phosphokinase. Between weeks 0 and 10, tetanic torque declined by about 60% (p < 0.001) in both groups, with no significant difference between the groups (p > 0.7). Between weeks 10 and 15, tetanic torque in the treated group increased by 0.81 Nm; this was significantly greater than the increase of 0.25 Nm in the placebo group (p < 0.05). The diameters of slow (type-1) and fast (type-2) fibers measured from the vastus lateralis muscle followed the same trend. At all time points, fiber diameter correlated strongly with torque; this argues against nonmuscular causes such as nerve injury for strength loss. The mean levels of insulin-like growth factor-1 increased 100% by week 4 in the treated group and remained elevated by about 60% throughout the experiment. Levels of insulin-like growth factor-1 in the placebo group decreased 30% within week 1 and remained depressed throughout the experiment. Our interpretation of these data suggests that the growth hormone secretagogue elevated levels of serum insulin-like growth factor-1, which in turn increased the size and strength of the quadriceps muscle during remobilization. These data may ultimately have therapeutic application to humans during rehabilitation after prolonged inactivity.

Topics: Animals; Atrophy; Dogs; External Fixators; Female; Growth Hormone; Hindlimb; Immobilization; Insulin-Like Growth Factor I; Muscle Contraction; Muscle Fibers, Skeletal; Muscle, Skeletal; Piperidines; Placebos; Spiro Compounds; Torque