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PubMed2005

Cumulative and bolus in vitro contracture testing with 4-chloro-3-ethylphenol in malignant hyperthermia positive and negative human skeletal muscles.

In this study we evaluated the in vitro effects of 4-chloro-3-ethylphenol (CEP) using cumulative (12.5-200 micromol/L) or bolus (75 and 100 micromol/L) administrations, on muscle specimens from malignant hyperthermia (MH) susceptible and MH nonsusceptible patients, respectively. In the cumulative CEP in vitro contracture test, contractures were significantly greater in the MH susceptible compared with the MH nonsusceptible muscles in all concentrations between 25 and 100 micromol/L. There was no overlap between the diagnostic groups at 75 micromol/L of CEP, so this test appears to be feasible for diagnosis of MH susceptibility. The two bolus tests are not diagnostically useful, as overlaps between the diagnostic groups were observed.

Adolescent↗
PubMed1978

Potassium contracture of smooth muscle in the presence of dextran.

The apparent diffusion coefficient of Ca ions in the extracellular space of guinea pig taenia coli was estimated from model experiments to be 3.2 x 10(-6) cm2 sec -1, while the relationship between Ca concentration in the medium and tonic tension in 40 mM K-contracture was measured in the same muscle both in the presence and absence of dextran 10. On the basis of these experiments and certain assumptions, the time course of tension decline by Ca withdrawal during K-contracture was calculated. Under all dextran concentrations tested (0--15%) the calculated time course of tension decline was in good agreement with one actually observed except in a short period of time immediately after Ca withdrawal. The results suggested that Ca distribution in the extracellular space during the loss of Ca is in good agreement with the diffusion theory in cylinder, and that each muscle fiber shows its tension without delay in response to the change in Ca concentration in the vicinity of the fiber according to the tonic tension-Ca relationship mentioned above. The discrepancy between calculation and observation was partially explained on an experimental basis.

Animals↗
PubMed1980

Ouabain potentiation of rapid cooling contracture of caffeinized cardiac muscles in calcium deprived medium.

To obtain further evidence concerning the intracellular action of ouabain, we observed the effect of this compound on contractures evoked by rapid cooling in the presence of caffeine (rapid cooling caffeine contracture; RCCC), in cardiac muscles under conditions of a Ca deprived medium. The experiments were carried out at 20 degrees C using cat papillary muscles and frog ventricle strips, with the exception of cooling (2 degrees C). The muscles were first immersed in normal solution, electrically driven, then immersed in 1 mM EDTA solution for 6 min. The strips were then immersed for 10 min in a caffeine solution prepared by eluting a no-Ca solution containing 50 mM caffeine through Dowex A-1, Ca-chelating resin. Finally, the caffeine solution was exchanged with fresh caffeine solution of 2 degrees C to evoke to RCCC. Ouabain (1 X 10(-7)--1 X 10(-5) M) markedly potentiated RCCC. An ouabain-induced increase of RCCC did not appear in the resting strips unless the tissues were electrically stimulated. 3H-ouabain occupied a considerable cellular space (0.55) at the appearance of the ouabain potentiation of RCCC (14C-inulin space; 0.20). The appearance of the ouabain potentiation of RCCC was independent of changes in 22Na, Ca2+ and ATP contents in the strips. A possible mechanism of the potentiating effect of ouabain on contraction is discussed.

Adenosine Triphosphate↗
PubMed1991

The external Ca(2+)-dependence of acetylcholine-induced contracture in single innervated and denervated skeletal muscle cells in mice.

We examined morphological differences and compared the Ca(2+)-dependence between acetylcholine (ACh)-contractures in normal and denervated skeletal muscle cells. ACh (1 microM - 1 mM) contracted the normal cells into a jackknife-shape. The higher the concentration of external Ca2+, the greater the ratio of responding cells/total cells observed and the sharper the angles of the "jackknives". ACh contracted the denervated cells into a compression-form, and the contraction was dependent on the external Ca2+. These results indicate that ACh-contractures in both normal and denervated cells are external Ca(2+)-dependent.

Acetylcholine↗
PubMed2001

Adenosine triphosphate alters the selenite-induced contracture and negative inotropic effect on cardiac muscle contractions.

Selenium is known to play an important role in the physiology of many different cell types and extracellular application of selenite causes cellular dysfunction in many different types of tissues. In a previous study, we have shown that in rat ventricles, sodium selenite (> or = 1 mM) caused an increase in the resting tension and a decrease in contractile force, in a time-dependent manner. In the present study, we have shown that sodium selenite caused a contracture state both in Langendorff perfused hearts and isolated papillary muscles. We also showed that the application of extracellular ATP (0.1 mM) markedly reduced this detrimental effect of sodium selenite on ventricular contraction in Langendorff perfused hearts and delayed it in isolated papillary muscle preparations. In contrast, isoproterenol (0.1 microM) did not seem to influence this action of sodium selenite in papillary muscle preparations. Possible reasons for this protective effect of ATP to selenite-induced contracture are also discussed.

Adenosine Triphosphate↗
PubMed2002

Multiple congenital contractures (congenital multiple arthrogryposis).

Arthrogryposis, is the occurrence of joint contractures of variable etiology that start prenatally. Arthrogryposis may result from neurologic deficit, neuromuscular disorders, connective tissue abnormalities, amniotic bands, [figure: see text] or fetal crowding. Arthrogryposis may result from no apparent hereditary causes (neuropathic, for example) or may be the result of hereditary factors (myopathic form, for example). Ultrasound diagnosis depends on observation of scant or absent motion of fetal extremities. Prognosis depends on the specific etiology of the contractures.

Abnormalities, Multiple↗
PubMed1976

Radioactive calcium influx at rest and during potassium contracture in the T-disrupted, and the urea- or manganese-treated frog sartorius muscles.

45Ca influx in the intact, the T-disrupted, and the urea-treated or Mn++-treated frog sartorius muscles was measured at rest and during potassium contracture. In the intact muscle, Ca influx increased with the increasing of potassium concentration in the bathing solution, and the time course of the Ca influx showed considerable correspondence with that of the potassium contracture. This increased Ca influx was divided into two components: early rapid Ca influx and late slow Ca influx. The amount of early rapid Ca influx at higher concentrations of potassium occupied about 60% of the total Ca influx. The early rapid Ca influx markedly decreased in the T-disrupted and in the urea-treated or Mn++-treated muscles. On the other hand, the late slow Ca influx and the resting Ca influx in these muscles changed only slightly. These results suggest that the early rapid Ca influx occurs mainly through the membrane of the T-system, particularly at the triadic junctional area of muscle fiber, while the late slow Ca influx and the resting Ca influx occur mainly through the surface membrane.

Animals↗
PubMed1979

Biphasic time course of inactivation of potassium contractures in single twitch muscle fibers of the frog.

The time course of the inhibition of peak tension (inactivation) of potassium contracture induced by conditioning depolarization with 10, 15, 20 and 30 mM K+ was examined, using single twitch fibers from the frog semitendinosus muscle. The time-dependence curve of the inactivation was biphasic, consisting of the first phase and the second phase. The first phase was characterized as follows: 1) the time course and the extent depend on the degree of conditioning depolarization; 2) the inactivation proceeds exponentially and finally reaches a steady level; and 3) the rate is markedly increased by lowering Ca2+ in the external medium. It could be considered that the first phase of the inactivation is an analogical phenomenon with the inactivation of sodium conductance in a squid giant axon. The second phase of the inactivation induced by conditioning with 20 and 30 mM K+ reached its full inactivation independently of the degree of conditioning depolarization. On the basis of these results, the terms inactivation 1 and inactivation 2 were given to the first phase and second phase, respectively, of the time-dependence curve of the inactivation of potassium contracture.

Animals↗
PubMed1980

Caffeine contracture in frog cardiac muscle after exposure to high concentrations of calcium.

Caffeine induced contracture in frog auricular muscle at room temperature when the muscle was exposed to a Ca-rich solution. The initial transient tension lasted 10-30 sec, and it was inhibited by procaine. It was dependent on caffeine concentration and the time of exposure to a Ca-rich solution prior to caffeine attack, but was little dependent on Ca concentration during caffeine contracture.

Animals↗
PubMed1988

The effect of lithium and nitrate on potassium contractures in a glycerol-treated slow-twitch muscle of the rat.

Glycerol treatment (0.4 or 1.2 M) altered but did not abolish twitch, tetanus, potassium, or caffeine contractures in the rat soleus at 37 degrees C. The use of nitrate Krebs or lithium Krebs greatly reduced the effects of 1.2 M glycerol treatment on potassium contractures. The data indicate that the rat soleus is relatively resistant to the uncoupling effects of glycerol treatment and that both lithium and nitrate largely prevent these effects.

Animals↗
PubMed2001

Sarcoplasmic reticulum Ca(2+) content affects 4-CmC and caffeine contractures of rat skinned skeletal muscle fibers.

This study investigated whether the sarcoplasmic reticulum Ca(2+) content of rat skeletal muscle fibers affected contractile responses obtained by an application of 4-chloro-m-cresol (4-CmC) and caffeine. Contractures were elicited on saponin-skinned fibers under different Ca(2+) loading conditions. The amplitude of 4-CmC and caffeine contractures of fast-twitch muscle fibers (edl, extensor digitorum longus) differed between the different loading conditions, and this is associated with a greater change in sensitivity to 4-CmC. When the sarcoplasmic reticulum was loaded with a low Ca(2+) concentration for a short period, the 4-CmC concentration providing half-maximal response was tenfold higher than with a larger sarcoplasmic reticulum Ca(2+) loading for a longer period, whereas for caffeine this concentration was only twofold higher in the same conditions. These findings indicate that 4-CmC contractile responses of edl muscle fibers are more dependent on luminal Ca(2+) activity than those of caffeine are. Thus 4-CmC would appear to be of greater interest than caffeine for the study of muscle contractile responses where variations in intracellular Ca(2+) activity exist.

Animals↗
PubMed1999

[Neurolysis and neuroplasty in patients with ischemic contracture of the foot].

The results of operative treatment of 24 patients with an ischemic foot contracture were analyzed, of them in 14 the reactive-restorational period of the disease was diagnosed and in 10--the residual one. The severity degree of contracture was determined according to classification of their own. The indication for operation were established basing on the results of clinical investigations and of electroneuromyography. In 18 patients the neurolysis of the leg nervous trunks was performed, in 6--interfascicular neuroplasty according to Millesi.

Compartment Syndromes↗
PubMed2000

[Malignant hyperthermia of Duchenne muscular dystrophy: application of clinical grading scale and caffeine contracture of skinned muscle fibers].

Episodes of acute myoglobinuria or cardiac arrest were occasionally complicated in general anesthesia of patients with Duchenne or Becker muscular dystrophy (DMD/BMD). Whether these complications are malignant hyperthermia (MH) or not has several times been discussed. In the present study, we applied the clinical grading scale (CGS) of Larach and modified criteria of caffeine contracture test of the skinned fiber (sIVCT) to solve this problem. When the CGS was applied to reported MH-like episodes of DMD/BMD cases, 9 out of 20 cases were classed as almost certain or very likely MH. According to results of sIVCT in 11 patients with DMD/BMD, 5 patients were judged as MHS (MH-susceptible) and 3 as MHE (MH-equivocal). The diagnostic specificity of present MHS criteria was 100% for the fulminant MH. A possible "false positive" result in European IVCT has been discussed in relation to myopathy such as muscular dystrophy. When we applied our sIVCT to the muscle of mdx mouse, caffeine contracture was rather reduced compared to controls. Present study suggested that a true MH was complicated in some cases of DMD/BMD. In certain stage of muscular degeneration, patients with DMD/BMD become susceptible to MH, probably temporarily, but exact mechanism still awaits clarification.

Animals↗
PubMed2000

Capsular contracture in augmentation mammaplasty.

In a group of 331 augmentation mammaplasties performed at the Clinic of Plastic Surgery in Prague from 1994-1998, capsular contracture was recorded in 6% cosmetic and 12% of reconstruction operations. The main cause was, in particular, the quality of tissue surrounding the implants along with individual disposition. The incidence of this complication did not differ significantly in relation to the placement of the prosthesis beneath the muscle or gland. Based on histological analysis and the clinical finding, it is obvious that disintegration of the prosthesis does not always lead to severe grades of capsular contracture. It is despite the presence of foreign bodies in the connective tissue.

Adult↗
PubMedDate not supplied

Ischemic myocardial contracture ("stone heart"). A complication of cardiac surgery.

Stone heart or ischemic myocardial contracture is a complication of cardiopulmonary bypass characterized by contracture of the myocardium and inability to obtain cardiac output on manual massage. Stone heart has occurred only during aortic valve replacement and/or coronary artery bypass procedures. Predisposing factors are chronic congestive heart failure and myocardial hypertrophy with fibrosis secondary to longstanding aortic valve disease and/or coronary artery occlusive disease. Although the condition is rare, the outcome is usually fatal. Because of the biochemical and physiological implications of this syndrome, its prevention has been challenging. On the basis of our current concepts, prevention has been afforded by topical and general hypothermia and pretreatment with a small i.v. bolus of propranolol just prior to aortic occlusion. These measures have been utilized in potentially high-risk patients with the predisposition for stone heart and, thus far, the results have been satisfactory. The stone heart syndrome is an entity which should be recognized by all cardiac surgeons. Preventive measures must be aimed at protection of the myocardium during anoxic cardiac arrest.

Cardiac Output↗
PubMedDate not supplied

Can the presence of equinus contracture be established by physical exam alone?

The condition in which ankle dorsiflexion is restricted is known as equinus contracture (EC). Equinus contracture is purported to be associated with a number of clinical conditions. However, there are no data to support or refute a clinician's ability to diagnose EC by clinical exam. We prospectively evaluated the maximum ankle dorsiflexion with the knee fully extended in 68 people (34 patients with isolated fore- or midfoot pain and 34 asymptomatic subjects) both by clinical exam and by a custom-designed ankle goniometer. We compared the likelihood of agreement of the clinical impression (equinus, no equinus) to the maximum ankle dorsiflexion measured with the instrument at two different numerical definitions of EC (< or =5 degrees and < or =10 degrees of maximum dorsiflexion). When all subjects were included and equinus defined as < or =5 degrees of ankle dorsiflexion, a clinician's ability to detect the equinus when it is truly present is 77.8%. If equinus is defined as < or =10 degrees, this ability increases to 97.2%. Alternatively, if equinus is not present, as defined by < or =5 degrees, then a clinician's ability to correctly diagnose no equinus is 93.8%. If equinus is defined to < or =10 degrees, this ability decreases to 68.8%.

Adult↗
PubMed2001

[Correction of esophageal contracture in its cicatricial stenosis after chemical burn in children].

Esophageal contracture occurs in presence of its cicatricial changes and is characterized by shortening of the organ, the hiatal hernia of diaphragm formation and reflux-oesophagitis, which supports inflammation in the oesophagus and prevents epithelization of the affection zone, causing further stenosing. In 11 children, aged from 1.5 to 6 yrs, with postburn cicatricial oesophageal stenosis the operative intervention was performed, consisting of oesophageal mobilization in mediastinum and its lengthening according to method of Collis with simultaneous fundoplication. Performance of the oesophageal contracture correction in children had permitted to prevent oesophageal inflammation, to restrict the stenosis progress, secured to do segmental oesophageal resection in 2 observations.

Burns, Chemical↗
PubMed1976

The effect of SO24-, NO-3, Ca2+ and temperature upon sodium-free contracture, isotonic and isometric contraction of the isolated rat right ventricle.

Sodium-free contracture was directly dependent on the presence of Ca2+ in Tyrode sulphate solution. The first phase of contracture increased in Tyrode nitrate solution more quickly than in sulphate solution, while the second phase was the same. Higher amplitude of isotonic contractions was observed on substituting nitrates for chlorides in the Tyrode solution than in sulphate substitution. In Tyrode sulphate solution, spontaneous contractions appeared in 50% of the experiments. The relationship between the duration and tension of isotonic contraction, given the same pre-loading, showed greater diminution of the contractions, at the lower temperature (22 degrees C) than at the higher temperature (35 degrees C), whereas passive stretching of the muscle was not influenced by the temperature. Isometric contrations lasted longer at the lower temperature. The amphlitude of isometric contractions was directly correlated to the frequency of electrical stimulation at a constant temperature (22 degrees C). The results showed that shifts of the calcium participating in contraction of the rat ventricle are influenced both by the anion and cation content of the medium and by its temperature.

Animals↗