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External physical stimulation of the human fetus during episodes of low heart rate variation.

The effect of shaking the fetus through the maternal abdomen during episodes of low (nonreactive) fetal heart rate variation was studied in 10 healthy nulliparous women near term. Heart rate monitoring from an abdominal electrocardiogram was combined with real-time scanning for body movements and fetal breathing. In each fetus two episodes of low variation were examined, one during which external stimulation was performed and one as a control without stimulation. There were no differences between the groups, with or without stimulation, in the duration of the nonreactive trace or heart rate variation or in the incidence of breathing or body movements. Therefore, shaking the fetus during a nonreactive heart rate episode has no useful purpose. The results are comprehensible in the light of fetal and neonatal behavioral states.

Electrocardiography↗

Effects of physical stimulation with electromagnetic field and insulin growth factor-I treatment on proteoglycan synthesis of bovine articular cartilage.

OBJECTIVE: To investigate the single and combined effects of electromagnetic field (EMF) exposure and the insulin growth factor-I (IGF-I) on proteoglycan (PG) synthesis of bovine articular cartilage explants and chondrocytes cultured in monolayers. DESIGN: Bovine articular cartilage explants and chondrocyte monolayers were exposed to EMF (75Hz; 1.5mT) for 24h in the absence and in the presence of both 10% fetal bovine serum (FBS) and IGF-I (1-100ng/ml). PG synthesis was determined by Na(2)-(35)SO(4) incorporation. PG release into culture medium was determined by the dimethylmethylene blue (DMMB) assay. RESULTS: In cartilage explants, EMF significantly increased (35)S-sulfate incorporation both in the absence and in the presence of 10% FBS. Similarly, IGF-I increased (35)S-sulfate incorporation in a dose-dependent manner both in 0% and 10% FBS. At all doses of IGF-I, the combined effects of the two stimuli resulted additive. No effect was observed on medium PG release. Also in chondrocyte monolayers, IGF-I stimulated (35)S-sulfate incorporation in a dose-dependent manner, both in 0% and 10% FBS, however, this was not modified by EMF exposure. CONCLUSIONS: The results of this study show that EMF can act in concert with IGF-I in stimulating PG synthesis in bovine articular cartilage explants. As this effect is not maintained in chondrocyte monolayers, the native cell-matrix interactions in the tissue may be fundamental in driving the EMF effects. These data suggest that in vivo the combination of both EMF and IGF may exert a more chondroprotective effect than either treatment alone on articular cartilage.

Animals↗

Groningen Active Living Model (GALM): stimulating physical activity in sedentary older adults.

BACKGROUND: A significant number of Dutch older adults can be considered sedentary when it comes to regular participation in leisure-time physical activity. Sedentariness is considered a potential public health burden-all the more reason to develop a strategy for stimulating older adults toward becoming more involved in leisure-time physical activity. The Groningen Active Living Model (GALM) is a behavioral change strategy for stimulating participation in leisure-time physical activity. METHODS: The GALM strategy is based on a process model of behavioral change in which behavioral change is seen as a multidimensional and dynamic process. The strategy has three phases: recruitment, introduction, and follow-up, and lasts 18 months. RESULTS: Preliminary results indicate that, up until the summer of 1998, about 4000 older adults were participating in 76 local GALM projects. Further research will be done to assess the validity of the model and its effects on the leisure-time physical activity pattern, ADL performance, and health in newly active older adults. CONCLUSIONS: The GALM strategy is a feasible strategy for stimulating leisure-time physical activity participation on a large-scale basis. The strategy is being implemented in The Netherlands on a nationwide basis.

Activities of Daily Living↗

Groningen active living model (GALM): stimulating physical activity in sedentary older adults; first results.

BACKGROUND: A significant proportion of older adults in The Netherlands does not regularly participate in leisure-time physical activity. The Groningen Active Living Model (GALM) was developed to change this situation for the better. In this article the first results with respect to the validation of the model are presented. METHODS: We obtained cross-sectional data from a sample of 392 potential participants. Scores on the potentially causal variables (self-efficacy, social support, perceived fitness, and enjoyment) and the stages of change give a first indication of the potential validity of the GALM behavioral change model. RESULTS: Seventeen percent of the subjects could be categorized as in the precontemplation stage, 42% in the contemplation/preparation stage, and 39% in the action/maintenance stage. Data with respect to stages of change were missing for 2% of the subjects. Scores on all potentially causal variables rose significantly from the precontemplation to the action/maintenance stage. Discriminant analysis resulted in a canonical correlation of 0.58 between the precontemplation and the contemplation/preparation stages and 0.59 between the contemplation/preparation and action/maintenance stages; respectively, 82.6 and 78.3% of the subjects had been classified correctly. CONCLUSIONS: The results found in this study support our hypothesis, as described in the conceptual theory of the GALM behavioral change model. For a more comprehensive validation of the model's action theory and conceptual theory, follow-up measurements are required.

Aged↗

Groningen Active Living Model (GALM): stimulating physical activity in sedentary older adults; validation of the behavioral change model.

BACKGROUND: A significant proportion of older adults in The Netherlands do not participate regularly in leisure-time physical activity. The Groningen Active Living Model (GALM) was developed to change this situation for the better. Longitudinal results of the validation of the GALM behavioral change model are presented. METHODS: We obtained data on potentially mediating variables of physical activity behavior change (self-efficacy, social support, perceived fitness, and enjoyment) from 96 participants in a prospective study during the 18 months the GALM strategy lasted. RESULTS: Prospective analyses revealed significant differences in several potentially mediating variables, although some of these differences were contrary to our hypothesis. Discriminant analysis resulted in canonical correlations of 0.50 after 6 months and 0.66 after 18 months of program participation between adherers and nonadherers, respectively; 73.8 and 80.0% of the subjects were classified correctly. CONCLUSIONS: Based on the results, it can be concluded that we partially succeeded in manipulating the potentially mediating variables by means of our GALM strategy. Several mediating variables were identified that reliably discriminated long-term adherers from nonadherers, expanding the generalizability of social cognitive theory-driven variables to a Dutch population.

Aged↗

Effects of stimulated physical activity on the circadian pacemaker of vertebrates.

A dogma in the field of circadian rhythms is that in order to keep accurate time, pacemakers that generate such rhythms must be relatively independent of changes in the external and internal environment. While it is true that the period of circadian oscillators is conserved within a narrow range, regardless of alterations in the external and internal environment, numerous perturbations have now been found that can change the period and/or induce a phase shift in circadian pacemakers. Many of these perturbations also alter the overall level of activity and/or metabolic state of the organism. In 1960, Aschoff suggested that alterations in the "level of excitement" may induce changes in circadian clocks. Although little attention has been given to this hypothesis over the past three decades, recent findings support its validity and open new avenues for studying the function and organization of circadian clock systems.

Animals↗

Cross talk between physical activity and appetite control: does physical activity stimulate appetite?

Physical activity has the potential to modulate appetite control by improving the sensitivity of the physiological satiety signalling system, by adjusting macronutrient preferences or food choices and by altering the hedonic response to food. There is evidence for all these actions. Concerning the impact of physical activity on energy balance, there exists a belief that physical activity drives up hunger and increases food intake, thereby rendering it futile as a method of weight control. There is, however, no evidence for such an immediate or automatic effect. Short (1-2 d)-term and medium (7-16 d)-term studies demonstrate that men and women can tolerate substantial negative energy balances of < or = 4 MJ energy cost/d when performing physical activity programmes. Consequently, the immediate effect of taking up exercise is weight loss (although this outcome is sometimes difficult to assess due to changes in body composition or fluid compartmentalization). However, subsequently food intake begins to increase in order to provide compensation for about 30% of the energy expended in activity. This compensation (up to 16 d) is partial and incomplete. Moreover, subjects separate into compensators and non-compensators. The exact nature of these differences in compensation and whether it is actually reflective of non-compliance with protocols is yet to be determined. Some subjects (men and women) performing activity with a cost of < or = 4 MJ/d for 14 d, show no change in daily energy intake. Conversely, it can be demonstrated that when active individuals are forced into a sedentary routine food intake does not decrease to a lower level to match the reduced energy expenditure. Consequently, this situation creates a substantial positive energy balance accompanied by weight gain. The next stage is to further characterize the compensators and non-compensators, and to identify the mechanisms (physiological or behavioural) that are responsible for the rate of compensation and its limits.

Anorexia↗

Increased myometrial contracture frequency at 96-140 days accelerates fetal cardiovascular maturation.

Fetal cardiovascular responses to an altered intrauterine environment of increased myometrial contractures induced by oxytocin (OT) pulses to the ewe over the final 50 days of gestation were studied in chronically instrumented sheep. Ewes received saline (Cntl) or long-term OT treatment (LTOT, 600 microU x kg(-1) x min(-1) in 5-min pulses every 20 min) from 96 days gestational age. Fetal baroreflex responses to sodium nitroprusside (SNP) and phenylephrine (PE) were studied at 133 days gestation. OT increased contractures in LTOT ewes. Fetal blood pressure (FBP) was higher, and fetal heart rate (FHR) and slope of daily change in FBP and FHR were lower in LTOT fetuses. Fetal SNP-induced hypotension resulted in a narrow R-R interval variation range in LTOT fetuses; Cntl fetuses showed early breakdown in compensation. Baroreflex response slope during PE-induced fetal hypertension was lower in LTOT than in Cntl fetuses. Although the cortisol-to-ACTH ratio was lower in LTOT fetuses, fetal plasma ACTH and cortisol changes were similar in control and LTOT fetuses. We hypothesize that contracture-induced alterations in the intrauterine environment accelerate fetal cardiovascular development through mild hypoxemia, repetitive fetal pituitary-adrenal stimulation, and/or physical stimulation.

Animals↗

[The analgesic and antispasmodic effects of guang tong xiao aerosol of TCM].

OBJECTIVE: To observe the analgesic and antispasmodic effects of Guang Tong Xiao Aerosol (GTXA). METHOD: Writhing test and tail-flick of physical stimulation were made to study the analgesic effect on mice and rats. RESULT AND CONCLUSION: GTXA given by gastrogavage in dose of 18.75 g.kg-1 or 12.50 g.kg-1 could markedly raise the pain threshold after chemical stimulation in mice and physical stimulation in rats, and had antispasmodic effects.

Aerosols↗

[Urticaria and mast cells in adolescence].

Adolescent patients are often affected by dermographic, cholinergic, cold or solar urticaria brought about by distinct physical stimulation. These physical forms of urticaria as well as cutaneous and systemic mastocytosis are due to the release of inflammatory mediators from the mast cells. As these diseases usually show characteristic cutaneous symptoms, they can easily be distinguished from other subtypes of urticarial reaction. In order to make the reader familiar with physical urticaria and mastocytosis, we describe the clinical features, pathogenic factors, and therapeutic possibilities of these disorders in adolescence.

Adolescent↗

Level of consciousness affects the excitability of spinal motor neurones during propofol sedation in humans.

BACKGROUND: To investigate the relationship between the depression of spinal motor neuronal excitability and the sedative level induced by propofol infusion, we simultaneously analysed the suppressive effect of propofol on the F wave and the sedative level during propofol infusion. METHODS: After spinal anaesthesia, sedation was achieved using a propofol target-controlled infusion (TCI) system to achieve a score of 4 on the Wilson sedation scale. The excitability of spinal motor neurones was determined by measuring the left median nerve F wave. F-wave persistence and the F/M ratio were recorded at pre-sedation as the control, during sedation, at arousal by mild physical stimulation and at post-sedation. RESULTS: Wilson sedation scores increased significantly corresponding to the increase in the target propofol concentration (Cpt), and a Cpt-producing Wilson sedation scale 4 ranged between 1.2 and 1.8 microg ml(-1). The F-wave persistence and F/M ratio before propofol infusion were 80.7 (8.6)% and 9.5 (3.9)%, respectively. At Wilson sedation scale 4, F-wave persistence and F/M ratio were 17.6 (12.8)% (0-37.5%) and 4.3 (4.1)%, and, at return of consciousness by mild physical stimulation, significantly increased to 71.3 (7.9)% and 10.0 (5.0)%, respectively. CONCLUSION: We demonstrated that the excitability of spinal motor neurones was suppressed during sedation by propofol TCI, but this suppressive effect vanished at return of consciousness by mild physical stimulation even at a constant Cpt. Our data suggested that the effect of propofol on the excitability of spinal motor neurones might be affected by consciousness level rather than propofol Cpt in humans.

Adult↗

Effect of mechanical strain on gastric cellular migration and proliferation during mucosal healing: role of Rho dependent and Rac dependent cytoskeletal reorganisation.

BACKGROUND: Various factors affect gastric wound healing. The influence of physical stimulation on gastric mucosal cells during the process of gastric wound healing is not completely understood. AIMS: To assess the role of a physical stimulant, in this case mechanical strain, on gastric mucosal restoration. METHODS: Mechanical strain was applied to adherent rat gastric mucosal cells (RGM1) cultured confluently on collagen type I coated silicone elastomer membrane in order to increase the dimension by an average of 5% and 10% at 5 cycles/minute for 72 hours after wounding. Repair of the wound was monitored every 12 hours for up to 72 hours using an inverted phase contrast microscope. Cell proliferation was detected using 5-bromodeoxyuridine staining. The cytoskeletal protein actin, a component of focal adhesion plaque protein, vinculin, and the small GTP-binding proteins RhoA and Rac1 were detected by immunohistochemistry in the cells located at the margin of and remote from the wound. RESULTS: The cells located at the margin of the wound showed the greatest migration and proliferation and were found to express more rudimentary lamellipodia and filopodia in the absence of mechanical strain. Vinculin, RhoA, and Rac1 were also strongly expressed in the wound margin. Under conditions of mechanical strain, the speed of migration of cells slowed and fewer proliferating cells were detected around the wound in a strain strength dependent manner. Lamellipodial formation, vinculin, RhoA, and Rac1 were poorly expressed in the same area. However, in cells located more than 1 mm from the wound edge, cytoskeletal rearrangement, and the expression of vinculin, RhoA, and Rac1 were not influenced by mechanical strain. CONCLUSIONS: Migration and proliferation of RGM1 cells in culture during wound healing were inhibited by mechanical strain, which caused dysfunction of the cytoskeletal and cell adhesion systems. It is suggested that physical stimulants such as mechanical strain may play a role in gastric wound healing in vivo by modifying cellular migration and proliferation.

Animals↗

Change in fibrinolytic activity as a parameter for assessing local mechanical stimulation during physical exercise.

The influences of mechanical force during physical exercise on blood coagulation and fibrinolysis were investigated and the effects of sports equipment, especially shoes were also examined. As an experimental model, local mechanical vibration was applied to the palm of the hand. General coagulation parameters did not change, but fibrinolytic activity was elevated due to the tissue plasminogen activator (t-PA) released from vascular endothelial cells stimulated by vibration. The influence of mechanical stimulation by repeated side-jumping with bare feet was examined on the sole of the foot. As with t-PA, the von Willebrand Factor antigen (vWF:Ag) derived from vascular endothelial cells also tended to increase, but not as much as when wearing sports shoes. Sports shoes protected the blood vessels of the feet from damage by mechanical force during physical exercise. Changes in fibrinolytic activity and t-PA could be useful for assessing local mechanical stimulation during physical exercise and also as indexes for the development of new sports equipment and its improvement.

Adult↗

Endogenous metabolism of fungus spores: stimulation by physical and chemical means.

Endogenous respiration of spores of the fungus Myrothecium verrucaria can be stimulated up to over-10 fold by diverse chemicals or by physical treatments. Greatest effects were caused by azide (12-fold at 250 mum) and by 2,4-dinitrophenol (7-fold at 300 mum). Marked stimulation was also caused by 10 mum silver (5-fold), 30 mum pentachlorophenol (6-fold), 10 mum carbonyl cyanide m-chlorophenyl hydrazone (4.5-fold) and 10 mum merthiolate (4-fold). Physical treatments such as heat (50 C), freezing, and sonication at sublethal levels were also stimulatory. Stimulation by azide or dinitrophenol was much greater in young than in old spores, whereas response to other chemicals and to freezing was relatively unaffected by spore age. In older spores the effect of azide was no greater than some other inhibitors. During incubation with azide, the endogenous trehalose reserves decreased and changes in free amino acids occurred, both increases and decreases. Thus anabolic as well as catabolic changes occur as evidenced also by the germination of a few (up to 5%) spores. The mechanisms of stimulation must be varied and complex. Permeability changes in the membrane confining endogenous reserves are proposed as a common initial cause. Additional changes in characteristics of membranes of other subcellular particles, as well as enzymic phenomena such as uncoupling of oxidative phosphorylation, are presumably involved in instances where greater stimulation occurs. The data are consistent with the hypothesis that dormancy in these spores results from separation of substrates from metabolic enzymes and more specifically that metabolites are sequestered rather than enzymes.

Journal Article↗