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PubMed1992

[The influence of soft tissue contractures on the walking ability of patients with spastic cerebral palsy].

The influence of soft tissue contractures on walking ability was investigated in 73 patients with spastic cerebral palsy. The relationship between the degree of soft tissue contractures and ambulation level was analyzed using Hayashi's quantification theory type II. The walking energy expenditure and electromyography magnitude (E.M.G. magnitude) were also measured in 11 patients who could walk on treadmill. Hayashi's quantification theory type II showed a significant correlation between the degree of soft tissue contractures and ambulation level. Both energy expenditure and E.M.G. magnitude were found to be significantly higher than in normal subjects. The levels increased in relation to walking speed. A significant correlation between walking energy expenditure and the degree of soft tissue contractures was found using multiple regression analysis. From these results, it was concluded that the soft tissue contractures had a strong influence on ambulation level and walking energy expenditure in spastic cerebral palsy.

Adolescent↗
PubMed1992

Unique responses of immature hearts to ischemia. Functional recovery versus initiation of contracture.

The characterization of unique responses of immature hearts to ischemic injury is important in devising better methods of myocardial protection for neonatal cardiac operations. Two end-points used to assess the vulnerability of immature myocardium to ischemic injury, namely, the time between onset of ischemia to the beginning of contracture and the functional recovery after reperfusion, had yielded results that appeared to be contradictory. In this study both the immature and adult rabbit hearts were used to study these two end-points in the same model, to assess their relationships and physiologic implications. Our data confirmed that, although immature hearts have greater capacity than adult hearts for functional recovery after identical periods of ischemic insult, their times to ischemic contracture are not prolonged, as could have been expected. A negative correlation between the rise in resting myocardial tension (i.e., contracture) and the recovery of ventricular function after reperfusion was noted both in the neonatal and in the adult hearts. However, reperfusion undertaken after "the onset of contracture" showed that the ventricle could still regain a measure of its function, which indicates that the "irreversibility" in global ventricular function is a gradual and progressive phenomenon. Biochemical studies of sarcoplasmic reticular calcium-adenosinetriphosphatase activity indicated that the immature myocardium has a significantly lower activity of this enzyme. Further depression of this enzyme activity after ischemia is seen in the immature hearts and may in part explain the earlier onset of contracture reported. A unifying concept to explain these unique responses of neonatal hearts to ischemia is proposed, based on the immaturities of certain key enzymes. The implications of these findings in the development of better protective techniques are also discussed.

Adenosine Triphosphate↗
PubMed1978

Coenzyme dependent suppression of 2,2-PDS induced contractures in Spirostomum.

Spirostomum ambiguum was stimulated to contract by addition of the thiol inhibitor, 2,2-dithiobispyridine (PDS), which depletes intracellular reducing equivalents which are generated by coenzyme dependents reactions. PDS induced contractures were not suppressed after 2--4 h of pre-incubation in a medium enriched with ascorbic acid, thiamine, or riboflavin, singly. Two h of incubation with nicotinamide did not suppress contractures; however, 50% suppression occurred after 3 h incubation. Incubation of the cells in a medium enriched with all four coenzymes for up to 4 h, resulted in the suppression of PDS induced contractures to a level as low as 30% of control values. Suppression of contractures by the mixed coenzymes was concentration dependent. Cells that were stimulated with PDS and contracting, exhibited a 50% suppression of contractures within 3 min after transfer to a complementary medium enriched with mixed coenzymes. These results suggest that coenzymes interact synergistically with cellular metabolic processes to inhibit pharmacodynamic responses to PDS.

2,2'-Dipyridyl↗
PubMedDate not supplied

[Effects of agonists and antagonists of rhyanodine receptors on potassium contractures in twitch and tonic frog skeletal muscle fibers].

A comparative analysis of the effects of the concentrations of Ca2+ in external medium and the inhibitor (dantrolene) and activator (4-chloro-m-cresol) of rhyanodine-sensitive Ca2+ channels of carcoplasmic reticulum on the characteristics of potassium contracture in frog twitch and tonic skeletal muscles has been performed. It was shown that the duration of contracture in tonic muscles is not restricted by the presence of Ca2+, as distinct from twitch muscles. Dandrolene does not practically affect the contractile responses of tonic fibres, and the concentration of cresol eliciting the contracture for tonic fibres is substantially higher (1 mM) than for twitch fibers (0.25 mM). In twitch fibers, the potassium contracture activated in the presence of cresol is comparable in amplitude and dynamics with the contracture under control conditions, and in tonic fibers a summing of responses without relaxation after the washing of excessive potassium is observed. This suggests that, in twitch fibers, the influx of Ca2+ can directly create the concentration sufficient for the maintenance of contraction, and in tonic fibers its involvement is mediated through the Ca(2+)-dependent activation of the beta-isoform of rhyanodine-sensitive channels.

Animals↗
PubMed1989

Measurement of capsular contracture: the conventional breast implant and the Pittsburgh implant.

At present, there is no accurate, reliable method of experimentally measuring capsular contracture. This study had four goals: (1) to define the parameters of capsular contracture employing principles of biomechanics of soft tissues, (2) to develop laboratory techniques to measure the parameters, (3) to design an implant that mechanically impedes the process of encapsulation, and, (4) to test this implant against a conventional one. We have developed a breast implant (the Pittsburgh implant) with an altered surface topography. Its silicone shell is punctuated by projections 1 mm in height and 1 mm in diameter. Two techniques were devised to measure contracture. The first involved measuring the force deformation along a coronal axis. The second involved measuring hydrostatic pressures within the implant resulting from the injection of known quantities of saline. Measurements were performed in vivo on 36 animals. By both force and pressure measurements, the Pittsburgh implant showed less capsular contracture (p = 0.12 and 0.012, respectively). Histology revealed that the prototype surface alters the linear arrangement of myofibroblasts and redirects the laminar collagen into a waveform pattern. We conclude from this experimental study that an altered surface topography may serve as a means of rendering a capsule less mechanically effective. We feel that the proposed methods can be used in the laboratory to characterize the extent of capsular contracture.

Animals↗
PubMed1978

[Contracture of the myocardial fibers of the frog ventricle after high frequency stimulation while the calcium channels were blocked by manganese ions].

The contractile force of the myocardial strip of the frog ventricle stimulated by impulses of 0.5 Hz was diminished to 3--5% of the initial value when perfused with Ringer's solution containing 2.5 mM manganese. Under this condition the action potential duration was significantly decreased. An increase in frequency of stimulation up to 5 Hz leads to the development of contracture. The amplitude of contracture was about 30% of the initial contractile force in normal perfusion solution. The amplitude of contracture was more than doubled under the effect of ouabain (2 X X 10(-6) g/ml). Similar experiments with lanthanum failed to discover contracture produced by the increase of the stimulation frequency. In these experiments ouabain was also ineffective. It is supposed that contracture observed in the presence of manganese was caused by nonelectrogenic calcium transport into the muscle fibers.

Animals↗
PubMed1988

Fetal oxygen uptake during uterine contractures.

During contractures there are decreases in fetal oxygen tension. In order to determine if there are concomitant changes in fetal oxygen consumption, we calculated the latter during contractures from measurements of the umbilical blood flow and venous arterial oxygen content differences across the umbilical circulation. There were decreases in both the umbilical venous (from 8.8 +/- 0.2 (SEM) to 8.5 +/- 0.2 ml.dl-1, P less than 0.01) and umbilical arterial (5.9 +/- 0.1 to 5.2 +/- 0.2 mg.dl-1, P less than 0.001) oxygen contents. The umbilical venous-arterial oxygen content difference increased from 2.9 +/- 0.1 to 3.3 +/- 0.2 ml.dl-1 (P less than 0.005). Umbilical blood flow was 194.3 +/- 4.5 ml.min-1 kg-1 during relaxation and was unchanged during contractures. Fetal oxygen uptake increased from 5.7 +/- 0.3 to 6.5 +/- 0.4 ml.min-1 kg-1 (P less than 0.005) during contractures. This observation is consistent with our previous speculation that there is increased muscular activity of tone associated with contractures.

Animals↗
PubMed1987

Effect of pyridostigmine on tetanic contracture of innervated and denervated rat skeletal muscle.

Pyridostigmine has been reported to cause histological damage and decrements in tetanic contracture of skeletal muscle. Cholinesterase inhibition, decreased transmitter release and desensitization of postsynaptic receptors have all been proposed as mechanisms for these effects. The purpose of the present study was to determine whether the effect of pyridostigmine to decrease tetanic contracture was due to pre- or postsynaptic action. Rats with innervated or chronically denervated hindlimbs were given pyridostigmine (25 mg/kg) s.c. by infusion for four days. Tetanic contracture (20, 50, 100 Hz) was evoked by sciatic nerve stimulation in the innervated muscles and direct muscle stimulation in the denervated muscles. Pyridostigmine significantly decreased the contracture of innervated triceps surae muscle in a frequency dependent manner. Post-tetanic potentiation was reduced from control muscle responses. In denervated muscle pyridostigmine had no effect on contracture or post-tetanic potentiation. These results show that innervation is required for the detrimental effect of pyridostigmine and that the drug has no effect on skeletal muscle.

Animals↗
PubMed1987

[Role of disorders of calcium homeostasis in the development of ischemic contracture of the heart].

The development of ischemic contracture in rat was evaluated in relation to glycolytic production of ATP and Ca2+ homeostasis. When the rate of glycolysis was reduced by glycogen depletion (swimming at 33 degrees C for 2 h, administration of isoprenaline or heart perfusion with it), the rate of ischemic contracture development increased. Isoprenaline increased the development of contracture in a dose-dependent manner, and dexamethasone potentiated the effect of isoprenaline. The decrease in the intensity of ATP/P1 exchange, probably reflecting the intensity of glycolytic phosphorylation of ADP, which, in our conditions, arose from ATP hydrolyzed mostly by Ca2+-ATPase and Na, K-ATPase, correlated with the development of ischemic contracture. Experiments with the rapid equilibration of the extracellular compartment with Ca2+ in various concentrations in the presence or absence of verapamil suggest that the development of ischemic contracture depends on the rate of Ca2+ accumulation in myoplasm. This rate of Ca2+ accumulation correlates with the rate of glycogenolysis and glycolysis which seems to produce ATP for active transport of cations.

Adenosine Triphosphate↗
PubMed1984

Potassium-induced contractures in crab (Callinectes danae) muscle fibers.

The contractures induced by 20-200 mM [K+]o in single crab muscle fibers were resolved into two components. The first component, consisting of single twitches or brief tetanic contractions, was associated with electrogenic membrane responses. The second occurred after spiking subsided with an amplitude that increased linearly with the [K+]o between 20 and 90 mM. The amplitude and time course of the contractures elicited by a given [K+]o differed markedly between different fibers. Contracture reproducibility of a single fiber was best when 90 mM [K+]o was used. The K-induced contractures were abolished after brief (3 min) exposure of the fibers to a calcium-free solution and were greatly depressed by 8 mM procaine. The data suggest that the contractures require both Ca2+-influx across the sarcolemma and release of Ca2+ stored in the sarcoplasmic reticulum.

Animals↗
PubMed1981

The effect of metabolic inhibitors on strophanthidin-induced arrhythmias and contracture in cardiac purkinje fibers.

The effect of different metabolic inhibitors on the induction of spontaneous rhythms by strophanthidin was studied in canine cardiac Purkinje fibers perfused in vitro. Both the electrical and mechanical activity were recorded. Strophanthidin caused its usual effects (an increase and then a decrease in force, a steepening of diastolic depolarization, spontaneous rhythms and inexcitability, but no contracture). When strophanthidin administration was repeated in the presence of depressed oxidative phosphorylation (antimycin and hypoxia), the force increased less and spontaneous rhythm occurred without the development of contracture. When strophanthidin was administered in the presence of blockade of glycolysis (iodoacetic acid and 2-deoxy-D-glucose), strophanthidin increased force even more than in the control test but steepened diastolic depolarization less or not at all and induced contracture. In some preparations, spontaneous rhythms developed but then only before the development of contracture. Hypothermia also increased the duration of the twitch and prevented the oscillatory potentials. Strophanthidin-induced arrhythmias were present in hypoxia but were prevented in hypoxia plus 2-deoxy-D-glucose. When metabolic blockade was severe (irreversible stage of antimycin action), contracture also developed, but spontaneous activity failed to appear. It is concluded that the oscillatory potentials induced by cardiac steroids are sensitive to blockade of glycolysis or severe metabolic blockade, possibly as a consequence of an impaired reuptake of calcium into sarcoplasmic reticulum.

Animals↗
PubMed1994

The effect of Siltex texturing and povidone-iodine irrigation on capsular contracture around saline inflatable breast implants.

A prospective, controlled, and blinded clinical study was performed on 56 patient volunteers to determine the effects of two independent variables--the Siltex textured inflatable implant and povidone-iodine irrigation--on the incidence of fibrous capsular contracture following retromammary augmentation. Each patient was randomly assigned both textured and smooth implants and povidone-iodine and saline irrigation, so that each patient served as her own control. The Siltex devices experienced an incidence of class III-IV contracture of only 2 percent, as compared with an incidence of 40 percent around the smooth devices. Most patients, however, preferred the smooth devices despite the higher contracture incidence because the Siltex device was more easily palpable. Povidone-iodine did not reduce the final incidence of contracture. It appeared to delay the onset of contracture, but not with statistical significance.

Adult↗
PubMed1976

[Experments on the mechanism of action of vascular spasmolytic agents. I. Effect nitroprusside sodium, nitroglycerine, prenylamine and verapamil on the arrested potassium contracture of isolated coronary arteries].

On the potassium contracture of isolated coronary arteries of cattle, the relaxation effected by calcium depletion can be blocked by lanthanum ions. The contracture persisting in calcium-free solution (arrested potassium contracture) is used to differentiate the sites of attack of spasmolytics. Verapamil and prenylamine are ineffective in this contracture model. By contrast, nitroprusside sodium and nitroglycerol as before act spasmolytically. Thus, both groups of drugs act through basically different sites. The findings are consistent with the hypothesis that the spasmolytic action of verapamil and prenylamine is based on a blockade of calcium influx. For nitroprusside sodium and nitroglycerol such a mechanism on the arrested potassium contracture has to be ruled out.

Animals↗
PubMed2006

Lethal congenital contracture syndrome (LCCS) and other lethal arthrogryposes in Finland--an epidemiological study.

Arthrogryposis multiplex congenita is a heterogeneous group of disorders characterized by multiple contractures with an estimated frequency of 1 in 3,000 births. With improving diagnostic methods, increasing numbers of fetuses with arthrogryposis are found. The pathogenetic mechanisms are relatively well known but the epidemiology and genetics of the prenatally lethal forms of arthrogryposis are less well known. In this study we collected all cases of a multiple contractures diagnosed in Finland during 1987-2002 including live born infants, stillbirths, and terminated pregnancies. Ninety-two cases of 214 suffered intrauterine demise (68 selective pregnancy terminations and 24 stillbirths) and 58 died in infancy. In 141 out of these cases the diagnosis could be included within lethal arthrogryposes, with a prevalence of 1 in 6,985 (1.43/10,000) births. Of these, 59 had spinal cord pathology at autopsy and thus were of neurogenic origin. Thirty-nine cases had lethal congenital contracture syndrome (LCCS) clinically characterized by total immobility of the fetus at all ultrasound examinations (12 weeks or later), multiple joint contractures in both upper and lower limbs, hydrops, and fetal death before the 32nd week of pregnancy. LCCS is noted as a unique Finnish disorder with a prevalence of 1 in 25,250 (0.40/10,000) births and is a major cause of lethal arthrogryposis in Finland.

Arthrogryposis↗
PubMed2001

Effect of elbow flexion contractures on the ability of people with C5 and C6 tetraplegia to lift.

BACKGROUND AND PURPOSE: It is commonly assumed that minor elbow flexion contractures prevent people with C5-C6 tetraplegia and paralysis of the triceps brachii muscles from bearing full body weight through their upper limbs. The aim of the present study was to determine the effect of simulated bilateral elbow flexion contractures on the ability of these individuals to bear weight through their upper limbs and to determine whether full passive elbow extension is truly critical for lifting body weight. METHOD: A biomechanical study was performed. Body weight lifted was measured under conditions that simulated bilateral elbow flexion contractures. Five people with motor complete C6 tetraplegia and one person with motor complete C5 tetraplegia, all with bilateral paralysis of the triceps brachii muscles, were recruited to the study. Subjects were fitted with bilateral elbow splints that restricted elbow extension but did not restrain elbow flexion nor prevent the elbow from collapsing, and were seated on an instrumented platform that measured vertical forces under the buttocks. Subjects pushed down through their hands and lifted under five different conditions, namely: with no elbow splints; with bilateral elbow splints adjusted to restrict elbow extension by 5-10 degrees; by 15-20 degrees; by 25-30 degrees and with bilateral elbow splints adjusted to allow unrestricted movement of the elbow joint. Maximal weight lifted from under the buttocks, for each condition, was expressed in relation to weight under the buttocks during unsupported sitting (that is, 'seated body weight'). RESULTS: Subjects lifted progressively less weight from under their buttocks as passive elbow restriction was progressively restricted. However, one subject lifted all his seated body weight when elbow extension was restricted by 5-10 degrees and another lifted all his seated body weight when elbow extension was restricted by 5-10 degrees and 15-20 degrees. CONCLUSIONS: Minor elbow flexion contractures will not alone prevent people with tetraplegia and paralysis of the triceps brachii muscles from lifting. Full passive elbow extension is not critical for the performance of this task.

Adult↗
PubMed2001

[Dupuytren contracture in North Germany. Epidemiological study of 500 cases].

Dupuytren's disease is the "classical" hand illness of the north: it affects people of Celtic or Viking descent throughout the whole of northern Europe, whereas it is an unknown disease in the Mediterranean region. Dupuytren's contracture appears to be an extremity-related disease. Owing to the unclear etiology and a lack of up-to-date demographic data for northern Germany this study aims--together with the literature--to elucidate the role of associated illnesses in an attempt to discover pathogenic explanations. 566 patients suffering from Dupuytren's disease in the area around Hanover were analysed with respect to epidemiological features and their Tubiana contracture stage. 91.2% were of pure northern German stock, 12.5% had a family predisposition. The male-to-female ratio was 7:1. Men were afflicted on average at the age of 56 years. Intellectuals were scored 3.17, while manual workers scored 4.21. There were pre-existing ipsilateral lesions in 15% of cases. 55.1% had bilateral contracture. Ectopic penile and plantar fibrosis or knuckle pads were found in 6.7% of cases. The distribution of stages I-IV decreased by 2.4% from 59.1% among the 1,808 afflicted finger rays. With a score of 3.7-3.72, drinkers and smokers presented significantly more severe contractures, while the 8.2% of diabetics displayed a milder form. Among the epileptics--all of whom were affected bilaterally--the Tubiana stage of 3.71 exceeded the median manual score of 3.63 for the group as a whole. Thus Dupuytren's disease is a general but not an exclusively extremity-related sickness. The androtropy is pathognomic. Women develop the disease one decade later than men. In old age the male-to-female ratio equalizes. Drinkers, smokers and heavy manual workers present a more severe affliction, while diabetics suffer from a significantly less severe form. Although the ulnar type dominates, the radial type accounts for 14.4% of cases. 1.9 million Germans are chronically ill because of Dupuytren's disease. Despite a trauma history, Dupuytren's disease is not recognized as an occupational disease.

Adult↗
PubMed2001

[Contracture of the elbow joint. Etiological review and general treatment concepts].

The contracture of the elbow joint is a symptom of various local changes and systemic disorders. Appropriate therapy requires a distinct knowledge of the relevant anatomical structures as well as of the etiology and pathogenesis of the functional restriction. Systematically, intrinsic contractures coming from the synovial membrane and intra-articular structures are distinguished from extrinsic contractures involving extra-articular soft tissues. The etiology of heterotopic ossifications is still widely unknown. The classification of the contracture is defined by the by extent of the remaining range of motion. Indications for surgery in severe cases depend on the degree of pain and of functional loss. Surgical arthrolysis includes a large spectrum of possibilities ranging from endocopical procedures to prosthetic joint replacement. Complications are relatively frequent after surgery and the individual gain of function is not always predictable.

Arthroplasty, Replacement↗
PubMed2004

Mammary compliance: an objective measurement of capsular contracture.

Capsular contracture is the most unpredictable complication after mammary augmentation. It presents an uncertain evolution, and is one of the most difficulty complications to treat. Evaluation of this condition usually was relegated to the surgeon's judgment, but currently there are three methods for measuring capsular contracture: palpation, applanation tonometry, and measure of mammary compliance. A prospective study was conducted to evaluate the different methods for managing capsular contracture. Particular attention was paid to the measure mammary compliance with a new device: the Anton Paar Mammacompliance system. This study found a good match between clinical and objective measurements, and also between the measure of applanation tonometry and the measure of mammary compliance. The Anton Paar Mammacompliance system seems to be effective in eliminating the descriptive part and keeping to the measurements and objective data. It is easily reproducible in the various check ups. It permits objective assessment for the measure of capsular contracture.

Adult↗