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At least 19 recordsLinked to original sources
PubMed1987

Changes in myocardial distensibility in rat papillary muscle: fibrosis, KCl contracture, hypoxic contracture, oxygen and glucose deficiency contracture, and experimental tetanus.

We describe diastolic properties of the myocardium in terms of stress-strain relations. In a mathematical analysis, the equation sigma = alpha(e beta.epsilon-1) of the stress-strain curve can be changed by an increase in the exponent beta or the multiplicative constant alpha. It can be experimentally shown that in hypertrophied myocardium of rats with essential hypertension and renal hypertension (SHR and Goldblatt rats, respectively), the steepening of the stress-strain curve is associated with an increase in the exponent beta (stiffness constant) and an enhancement of collagen content. On the other hand, in acute hypoxic myocardium, the slope of the stress-strain curve is increased without a significant change of the exponent beta. Our results from heat measurements and quick-release experiments indicate that the hypoxic contracture (H) and the oxygen and glucose deficiency contracture (HG) are in contrast to the results of depolarization contracture (KCl) and experimental tetanus (T). In H and HG, the cross-bridge cycling rate was found to be slowed by a factor of 2,000 compared to KCl and T. This means that ATP demand for force development and maintenance is 2,000 times less in H and HG than in KCl and T. We will further discuss the meaning and implications of these experimental findings.

Animals↗
PubMedDate not supplied

A review of the literature on the etiology of capsular contracture and a pilot study to determine the outcome of capsular contracture interventions.

The etiology of capsular contracture is unclear and probably multifactorial. This review covers the literature on several proposed contracture factors, including filler material, implant placement, surface texture, and bacterial infection. The pilot study's goal was to test the feasibility of a data collection form, which could be used in a scaled-up study analyzing multiple surgeon's records. The goal of the expanded version of this study will be to determine the efficacy of available interventions for capsular contracture, including surveillance. The Breast Implant Public Health Project, LLC (BIPHP), piloted a retrospective review of outcomes in women who had interventions to relieve capsular contracture or had chosen a wait-and-watch approach. An evaluation of the efficacy of various treatments can help women decide if they want to pursue treatment at all and, if so, which treatment might offer them the best solution. BIPHP researchers (E.E.A., M.E.) developed a data collection form after reviewing records of three surgeons (B.C., W.P., V.L.Y.). During the data collection using the same records, we tested a randomization process to identify women with capsular contracture who underwent various interventions, including a wait-and-watch strategy, and those who had no mention of any intervention or waiting approach. Data were gathered on a total of 90 breasts with capsular contracture (scored Baker I-IV or qualitatively), of which 45 underwent a total of 102 interventions for capsular contracture. Interventions were classified as "closed capsulotomy," "surgical," or "watchful waiting." Closed capsulotomy was performed most often (47%), followed by surgery (29%) and watchful waiting (21%). Presurgical Baker scores averaged higher in breasts that underwent surgery (3.1) than for watchful waiting (2.5) or closed capsulotomy (2.3). Though closed capsulotomies had 100% of outcomes scoring "improved" or "same," 58% of the breasts underwent the procedure more than once, suggesting that the favorable outcome was short-lived. The wait-and-watch approach resulted in scores of either "same" or "worse"; surgery (open capsulotomy, repositioning, or capsulectomy) resulted in 79% improved, 16% same, and 5% worse outcomes in breasts with outcomes listed. In all intervention procedure categories, outcomes were frequently unavailable; they were noted only 60% of the time (52/87). The missing 40% may have resulted from the doctor's failure to note it in the chart, satisfied patients not returning for additional treatment, or dissatisfied patients seeking treatment elsewhere. Generally, the data collection forms and procedures were workable; however, we uncovered issues to address in the scale-up of this pilot study: (1) the outcome report rate was 60%; (2) though Baker scores are commonly used to evaluate the degree of capsular contracture, it seems that grade I may have different meanings for different surgeons, which would need to be clarified; (3) participating surgeons will need to divulge standard-of-care items that they may not have included in medical records, but routinely performed (e.g., patient massage, use of prophylactic antibiotics); and (4) records were initially separated by "implant," then researchers realized that a more useful collection would be by "breast." The latter approach captures the history of the breast in one record, which may be more important to contracture than the differences in implants. With the modifications discussed, the study can be scaled up to encompass as many records as necessary to achieve robust statistical power. These data will add to the existing literature regarding factors associated with capsular contracture and identify factors that affect the successful outcome of capsular contracture interventions.

Breast↗
PubMed1978

Caffeine contracture in transverse tubules-disrupted fiber and effect of anomalous anions on the contracture in frog twitch fiber.

Caffeine contracture in transverse tubules-disrupted (T-disrupted) muscle preparation and the effect of anomalous anions (SCN and NO3) on the contracture in single twitch fibers or thin bundles consisting of 2 or 3 fibers of frog were investigated. The magnitude and the rate of rise of caffeine contracture tension were decreased by T-disruption and the decrease was more marked at lower concentrations of caffeine. No seasonal difference between summer and winter frogs on the effect of T-disruption on caffeine contracture was observed. On the other hand, the magnitude and the rate of rise of caffeine contracture tension in the intact preparation was increased by anomalous anions, whereas the rate of spontaneous relaxation of the contracture was decreased. The effect of SCN on caffeine contracture appeared 5 min after the pre-exposure of muscle preparation of SCN-Ringer solution, with the maximal effect appearing after 10 min. The threshold curve of caffeine contracture was shifted toward the lower caffeine concentrations by anomalous anions and the extent of the shift in the curve was more pronounced with SCN than with NO2. In contrast, the potentiating effect of these anions on the caffeine contracture completely disappeared in T-disrupted muscle preparation. On the basis of these results, the caffeine pathway to the sarcoplasmic reticulum, and the sites and mechanism of the action of anomalous anions on caffeine contracture are discussed.

Animals↗
PubMed1985

[Report on the diagnosis and treatment of muscular contracture. The Ad Hoc Committee of the Japanese Orthopaedic Association of Muscular Contracture].

Muscular contracture due to repeated intramuscular injections raised urgent questions from the medico-legal standpoint when a large number of children with quadriceps contracture was found in Yamanashi Prefecture in 1973. In 1975, the Japanese Orthopaedic Association formed an Ad Hoc Committee on Muscular Contracture to investigate the diagnosis and treatment of this particular condition. Since then, the Committee has studied the symptomatology, diagnosis, natural history, orthotic and operative treatment of quadriceps, deltoideus and gluteus contractures. The results have been reported annually to the Japanese Orthopaedic Association, and guidelines for diagnosis and treatment have been made available to its members. Quadriceps contracture can be classified into three types: the rectus femoris, vastus, and mixed types. The rectus femoris type represents 80 to 90 per cent of cases with quadriceps contracture, while the vastus type is quite rare. In both the rectus femoris and mixed types, operative treatment is suggested when the knee flexion is limited to 30 degrees or less in the prone position. Transverse division of the rectus femoris at the muscle belly is the standard operative procedure recommended for the rectus femoris type and gives very satisfactory results in most cases. In the mixed type, an additional division of the scarred portion of the vasti is needed. The ideal age for such procedures is near or after the end of growth. The vastus type is difficult to cure, but to improve the condition to a certain extent an operation is suggested when the knee flexion is limited to 45 degrees or less in the supine position. The operative procedure recommended is either release of the affected vasti at their insertion to the patella or Z-lengthening of the common tendon of the quadriceps. In deltoideus contracture, the Committee proposed a scoring system for evaluating the severity with the grade of abduction contracture and the opposite shoulder test as parameters. A score of 5 points or more indicates operative treatment. The operative procedure recommended is release of both the acromial part and the anterior fibers of the spinal part of the deltoideus. The ideal age for this procedure is 12 years or older. A dent produced by the operation distal to the acromion, however, has to be regarded as a cosmetic complication. To avoid this complication, advancement of the severed fibers of the deltoideus from the scapular spine to the acromion is needed. Such an advancement procedure is suitable for children of 14 or 15 years of age and leaves the natural round contour of the shoulder intact.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1983

Force generation in experimental tetanus, KCl contracture, and oxygen and glucose deficiency contracture in mammalian myocardium.

We studied the amount and time-course of tension recovery after quick releases (0.25 mm) during experimental tetanus, potassium chloride contracture (KCl), hypoxic contracture (H) as well as joint glucose and oxygen deficiency contracture (HG) in left ventricular papillary muscles of rat and right ventricular papillary muscles of cat myocardium. Both in experimental tetanus and KCl contracture, the tension recovery was finished within 200 ms after the release, and was 77% and 60% of initial tension fall, respectively. The Q10 value for the time constant of half of recovery tension was 2.5, and the time constants differed by the same factor between rat and cat myocardium. In H or HG contracture, we never could find any significant tension recovery process during the first 200 ms after a release, neither in late nor in very early stages of contracture tension generation. However, when longer observation periods (90 s) after a release were monitored, a slow tension recovery was observed which was at least 18% of initial tension fall. This data indicates fast, calcium-mediated cross-bridge cycling in experimental tetanus and KCl contracture. In contrast, the very slow tension recovery in H and HG contracture, which is consistent with recent myothermal data, can be interpreted as rigorlike cross-bridges with a very slow cycling rate, a long time of attachment in force-generating position and low energy turnover.

Animals↗
PubMed1986

Action of halothane on rat soleus muscle: temperature dependent induction of contractures and modification of caffeine and potassium contractures.

Halothane induced calcium-dependent contractures in rat soleus muscle at temperatures between 4 degrees C and 13 degrees C, but not at higher temperatures. The peak tension of the contractures increased as temperature was decreased below 13 degrees C. The magnitudes of the contractures were reduced by the addition of cobalt or lanthanum ions to the medium in the water bath. The anaesthetic also potentiated caffeine-induced contractures in muscle at 22 degrees C and 37 degrees C in a calcium-dependent manner. The contractures at 37 degrees C were more sensitive to the concentration of this ion than were contractures at 22 degrees C. Halothane increased peak tension and prolonged the time course of potassium-induced contractures, but did not alter their threshold values at either 22 degrees C or 37 degrees C. It was concluded that, in rat muscle, halothane may act at a site on the plasmalemma, retard the onset of inactivation and move the inactivation curve further from the resting membrane potential.

Animals↗
PubMed1985

Congenital contractural arachnodactyly. Report of a case and of an operation for knee contracture.

A patient with typical congenital contractural arachnodactyly followed up from the age of 12 years to the age of 48 is reported. He had spiderlike fingers and toes and marked contractures of the knees, ankles, toes, shoulders, elbows and fingers; the mobility of the hips and wrists was almost normal. Persistent knee contractures prevented him from walking. In his twenties he had an osteotomy of both femora and shortening of the patellar tendons which enabled him to walk for the first time in an upright position without external support. When seen at the age of 48 the range of movement of his knees was 0 to 90 degrees. He was working as a turner and had been doing so for almost 20 years.

Child↗
PubMed1986

[Dupuytren's contracture as an accident sequela. Can progression of Dupuytren's contracture be recognized as an accident sequela?].

A healthy nineteen year-old soldier suffered a contusion of the distal interphalangeal joint of the fifth finger. A flexion contracture ensued. Histologic examination of the excised tissue revealed Dupuytren's contracture. Despite several more operations, progressive Dupuytren's contracture made it necessary to amputate the little finger at the level of the proximal phalanx. This was accepted for disability purposes as an injury acquired during military service.

Adult↗
PubMed1980

Biphasic potassium contractures in frog single twitch muscle fibers and effects of various agents on the contractures.

The characteristics and the mechanism of the biphasic potassium contractures, i.e., an initial rapid contraction (initial component) and a slow secondary contraction (secondary component) were investigated in detail using single twitch fibers from the semitendinosus muscles of the frog, Rana japonica. The present experiments confirmed the results of CONSTANTIN (1971) and STEFANI and CHIARANDINI (1973) and further demonstrated that larger diameters (75--100 micron) of single fibers are required as one of the conditions for obtaining a biphasic potassium contracture. In addition, the effects of calcium removal from the external medium and the various agents, i.e., 2.5 microM dantrolene, 5 mM manganese ions, 7.5 mM procaine, 0.5 mM verapamil and 6.5 mM lincomycin on the initial and secondary components were examined. The pretreatment of a single fiber with calcium-free Ringer solution or with dantrolene or manganese ions mainly inhibited the secondary component, while it slightly or moderately inhibited the initial component in keeping with its steepness. In contrast, procaine, verapamil and lincomycin mainly inhibited the initial component, changing slightly or moderately the secondary component. It could be concluded, therefore, that the excitation-contraction coupling, i.e., the activation process of the initial component differs from that of the secondary component.

Animals↗
PubMed1977

The inhibitory effect of papaverine on respiration-dependent contracture of guinea pig taenia coli in high-K medium. I. The relationship between contracture and respiration.

Papaverine (Pap) inhibited a tonic tension development in guinea pig taenia coli induced by an elevation of the potassium concentration of the medium to 40 mM (40-K). The ID50 of Pap was 4.5 x 10(-6) M. Inhibition of the 40-K induced tonic tension by Pap was dependent on the calculated concentration of non-ionized form, but not the ionized form. Inhibition of the tonic tension by Pap and various metabolic inhibitors was not antagonized by raising the Ca++ concentration in the medium. Results obtained from simultaneous measurement of the 40-K induced O2 consumption and tension illustrated that the inhibition of O2 consumption rapidly induced the inhibition of the tension. Furthermore, glucose removal, amytal or Pap resulted in a progressive relationship between the inhibition of O2 consumption and the inhibition of tension. The inhibition of Pap as determined by O2 consumption was not reversed by application of 10(-4) M 2,4-dinitrophenol (DNP). These results plus graphical analysis of the mechanical response suggest that Pap may penetrate the cell membrane and inhibit mitochondrial respiration, thereby inhibiting this very respiration-dependent contracture.

Animals↗