Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “GRAVITATION”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,675 records · Page 93Linked to original sources
PubMed2004

Illusory gravitational forces affect aimed limb movements.

The authors report on 2 experiments in which participants produced rapid wrist-rotation movements in a clockwise direction to move a cursor from a home position into a target region. The display was constructed such that the target could be depicted above, below, or beside the home position, so that the clockwise wrist rotation could produce upward, downward, or rightward movements of the cursor. By parsing the movements into component submovements, the authors found that upward movements were consistently less forceful, as evidenced by shorter primary submovements, compared with downward and horizontal movements. Those results suggested a new virtual gravity illusion: Participants apparently overcompensated for the absence of the anticipated effects of gravity by adjusting the initial force they used to propel the cursor toward the target.

Adult↗
PubMedDate not supplied

[Human soleus fibers contractile characteristics and sarcomeric cytoskeletal proteins after gravitational unloading. Contribution of support stimulus].

The effects of support withdrawal and support stimulation on the contractile characteristics of human soleus fibers and cellular factors which influence them were studied. The experimental model of the "dry" head-out water immersion was used in the study. In this model, the hydrostatic pressure on different sites of the body surface are equal so that the experimental conditions are close to the complete supportlessness. A 7-day exposure to dry immersion resulted in a decrease in the maximal isometric tension of the skinned fibers, a decline in the myofibrillar Ca2+-sensitivity, and the relative loss of the titin and nebulin content. A significant decrease in the percentage of fibers containing slow myosin heavy chains was also observed after dry immersion. The application of the mechanical stimulator influencing the plantar support zones with a pressure of 0.2 +/- 0.15 kg/cm2 6 times a day for 20 minutes of each hour brought about a complete prevention of the above listed effects of dry immersion. The data obtained allow one to conclude that the decline in maximal tension and Ca2+-sensitivity as well as myosin shift and loss of sarcomeric cytoskeletal proteins are associated with the support withdrawal during the exposure to dry immersion.

Cytoskeletal Proteins↗
PubMed2004

Efficacy of two micro-gravitational protocols to treat chronic low back pain associated with discal lesions: a randomized controlled trial.

AIM: Chronic low back pain is the most expensive benign illness in the industrialized world and is defined as a bio-psycho-social syndrome where the biological aspect has a very reduced importance when compared to the psychological and social aspects. The rehabilitative treatment of mechanical chronic lower back pain aims to modify the pain first and then postural local and general disorders. Rehabilitation in water is characterized by the possibility of reducing the gravity environment and the resistance to all motion and also of improving the proprioceptors and baroceptors sensation. Another modality exists in order to generate within a reduced gravity impact by means of the use of support systems during gait. The aim of this study is to compare the efficacy of these rehabilitative treatments in chronic low back pain. METHODS: Forty patients suffering from chronic low-back pain aged 50 years or less, (average age 43.46 years - max 50, min 28) were randomly divided into 2 groups (A and B) homogeneous for sex and age. They had an imaging exam that was positive for lumbar hernia or protrusion and were able to perform the defined rehabilitation with a 3 times frequency for 7 weeks. The people were studied for 1 year. Outcome measurements included the VAS and BACKILL scales. RESULTS: At the end of rehabilitation, all groups showed a statistically significant decrease of VAS values (p<0.01) and increase in Backill values (p<0.01). VAS and BK levels 1 year after treatment did not change in group B and remained significantly different from basal values, whereas in group A they were significantly different from the values at the end of treatment. The NSAIDs-intake was significantly reduced both at the end of treatment and after 1 year (p<0.01) in both groups. CONCLUSIONS: Body relief locomotion proved to give better results then aquatic rehabilitation in chronic low back pain patients, even if placebo controlled studies are needed to definitively prove the efficacy of the method.

Journal Article↗
PubMed2004

Afferent and peripheral control of muscle fiber properties during gravitational unloading.

The present paper covers two series of the experiment studies performed in attempt to analyze the support-triggered cellular mechanisms, controlling the maintenance of tonic muscle fiber characteristics. Exposure to 7 day dry immersion induced significant decline of the human soleus single fiber peak isometric tension and the Ca(2+)-sensitivity of myofibrils. 30-40% losses of the relative content of titin and nebulin were found after immersion. The application of the plantar support stimulation device prevented all these alterations. In the second experimental series the treatment of hindlimb suspended rats with the Ca(2+)-binding agent (EGTA) allowed to prevent or attenuate all the above mentioned unloading-induced soleus fiber alterations. Thus it is concluded that resting Ca2+ accumulation in the unloaded fibers may be among the mechanisms involved in the changes of fiber properties during unloading.

Animals↗
PubMedDate not supplied

[Inertial forces during muscle contractions as a factor compensating for the insufficiency of gravitation influence].

An idea has been advanced that inertial forces emerging during active movements are able to compensate for the deficiency of weight. The idea is based on the conception that these forces are by their effect on biological objects analogous to gravity forces. Training facilities have been developed, and tentative estimations have been made. The definition of "inertial massage" is introduced.

Humans↗
PubMed1990

[Use of the halo-gravitation-extension in preoperative preparation in severe scoliosis].

Severe and fixed scoliosis needs a preoperative extension treatment to attain a good result of correction by spondylodesis. Halo-up-extension is a very simple, comfortable and successful method to prepare patients with a severe scoliosis for operation. From January 1981 to July 1989 we carried out the preoperative halo-up-Extension treatment at 45 patients. 39 of them had a severe scoliosis with a cobb-angle of more than 70 degrees. The correction by halo-up-Extension runs on an average of 35% of the total correction.

Adolescent↗
PubMed1986

[Role of the gravitation factor in the development of changes in the digestive system].

The functional state of the gastro-intestinal system of rats aboard of "Cosmos-782", "Cosmos-936" and "Cosmos-1129", was studied. The long-term exposure to zero-gravity resulted in activation of proteolytic enzymes, decrease of carbohydrases and redistribution of lipolytic activities in gastro-intestinal organs. Use of artificial gravity during the flights produced a favourable effect on the proteolytic enzymes.

Amylases↗
PubMed1977

Weightlessness and gravitational physiology.

Physiologic responses to the weightless environment have been documented in Skylab astronauts. Significant changes in cardiovascular responses, calcium metabolism, fluid distribution, and red blood cell mass are described. Although the data are limited and the sample size small, several hypotheses can be formulated. Future studies in a space laboratory setting offer the potential for understanding the effects of weightlessness on human physiology and the implications to medicine.

Action Potentials↗
PubMedDate not supplied

[Low-gravitational changes in the bone system].

This review surveys reported data and observations made by the present authors concerning the effect of real and simulated hypogravity on bones of man and various animals. Bone biomechanics and mechanisms of osteodystrophic changes in hypogravity are discussed. Based on published data about bone metabolism regulation, the concept of bone formation and degradation in normal gravity and hypogravity is advanced. The conclusion is made that hypogravity-induced changes obey regulation at different levels, with local mechanisms being predominant. It is emphasized that a detailed investigation of every component of this process may become an important contribution to space and clinical medicine.

Aerospace Medicine↗