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PubMed1996

Dichotomy of ischemic preconditioning: improved postischemic contractile function despite intensification of ischemic contracture.

BACKGROUND: Acceleration of ischemic contracture is conventionally accepted as a predictor of poor postischemic function. Hence, protective interventions such as cardioplegia delay ischemic contracture and improve postischemic contractile recovery. We compared the effect of ischemic preconditioning and cardioplegia (alone and in combination) on ischemic contracture and postischemic contractile recovery. METHODS AND RESULTS: Isolated rat hearts were aerobically perfused with blood for 20 minutes before being subjected to zero-flow normothermic global ischemia for 35 minutes and reperfusion for 40 minutes. Hearts were perfused at a constant pressure for 60 mm Hg and were paced at 360 beats per minute. Left ventricular developed pressure and ischemic contracture were assessed with an intraventricular balloon. Four groups (n=8 hearts per group) were studied: control hearts with 35 minutes of unprotected ischemia, hearts preconditioned with one cycle of 3 minutes of ischemia plus 3 minutes of reperfusion before 35 minutes of ischemia, hearts subjected to cardioplegia with St Thomas' solution infused for 1 minute before 35 minutes of ischemia, and hearts subjected to preconditioning plus cardioplegia before 35 minutes of ischemia. After 40 minutes of reperfusion, each intervention produced a similar improvement in postischemic left ventricular development pressure (expressed as a percentage of its preischemic value: preconditioning, 44 +/- 2%; cardioplegia, 53 +/- 3%; preconditioning plus cardioplegia, 54 +/- 4% and control, 26 +/- 6%, P<.05). However, preconditioning accelerated whereas cardioplegia delayed ischemic contracture; preconditioning plus cardioplegia gave an intermediate result. Thus, times to 75% contracture were as follows: control, 14.3 +/- 0.4 minutes; preconditioning, 6.2 +/- 0.3 minutes; cardioplegia 23.9 +/- 0.8 minutes; and preconditioning plus cardioplegia 15.4 +/- 2.4 minutes (P<.05 preconditioning and cardioplegia versus control). In additional experiments, using blood- and crystalloid-perfused hearts, we describe the relationship between the number of preconditioning cycles and ischemic contracture. CONCLUSIONS: Although preconditioning accelerates, cardioplegia delays, and preconditioning plus cardioplegia has little effect on ischemic contracture, each affords similar protection of postischemic contractile function. These results question the utility of ischemic contracture as a predictor of the protective efficacy of anti-ischemic interventions. They also suggest that preconditioning and cardioplegia may act through very different mechanisms.

Animals↗
PubMed1987

Effects of extracellular calcium and calcium channel blocker on silver-induced contractures in frog skeletal muscle fibers.

The mechanism by which Ag+ induces muscle contracture was elucidated by investigating the effect of external Ca2+ concentration and Ca2+ channel blocker on the maximum tension amplitude in single fibers from frog toe skeletal muscle. Five microM Ag+ induced two different types of contracture in the presence of external Ca2+ more than 0.1 mM, i.e., a phasic and a subsequent tonic contracture. The phasic contracture appeared only in fibers with intact T-tubules immersed in a solution with or without Ca2+ after a lag time of 5.7 +/- 0.9 s (N = 5). The maximum amplitude was 58% of the tetanus tension observed in the same fiber immediately before Ag+ exposure. Diltiazem at high-concentration (100 microM) inhibited the Ag+-induced phasic contracture only to a small extent (17%). The contracture was not affected by 1 microM TTX or 1 mM DAP at all. These results indicate that Na+, K+, and Ca2+ channels on the T-tubular membrane would not be attributed to the phasic tension development induced by Ag+. On the contrary, a tonic contracture did not require intact T-tubules. The amplitude and the rate of rise of the contracture depended on external Ca2+ concentrations and were inhibited by a high concentration of diltiazem. Neither 1 microM TTX nor 1 mM DAP affected them. Therefore, the tonic contracture seems to be triggered by Ca2+ which entered the muscle fiber through the surface but not T-tubular membranes.

4-Aminopyridine↗
PubMed1999

Comparison of palmar aponeuroses from individuals with diabetes mellitus and Dupuytren's contracture.

It is well known that Dupuytren's contracture is often associated with diabetes mellitus. Palmar fascia from individuals with diabetes mellitus and/or Dupuytren's contracture as well as controls were subjected to differential scanning calorimetry, biomechanical and biochemical analysis. The collagen denaturation temperature of the palmar aponeurosis from individuals with diabetes mellitus in the presence (71.0 degrees C) or absence of Dupuytren's contracture (70. 6 degrees C) was increased as compared with controls (68.5 degrees C), while this parameter was significantly reduced (about 3.5 degrees C) in contracture bands of Dupuytren's contracture. Stress relaxation experiments revealed that the viscous fraction was slightly reduced in diabetes mellitus (6.5%) vs. controls (8.3%), whereas in Dupuytren's contracture, irrespective of additional diabetes mellitus, a pronounced increase of this parameter was seen (36.5% vs. 24.5%) in the presence of diabetes mellitus. The time constants were significantly elevated by both disorders, this increase being more pronounced in Dupuytren's contracture. Taken together, these changes can be explained by increased cross-linking in diabetes mellitus, while in Dupuytren's contracture other structural changes, such as increased collagen type III content and loss of fascicular organization, play an additional role besides the finding of reduced cross linking.

Aged↗
PubMedDate not supplied

The effects of zafirlukast on capsular contracture: preliminary report.

Capsular contracture after breast augmentation is a distressing, troublesome event both for the patient and the surgeon. Fibrosis transforms the prosthesis into a hardened sphere, turning the initially satisfactory cosmetic result into a deformed mass. Treatment for capsular contracture can be either surgical, consisting of capsulotomy or capsulectomy with implant replacement, or pharmacologic, consisting of intracapsular instillation of steroids and antibiotics. The success rates for both types of treatment vary. Although capsular contracture is a multifactorial process, one common denominator in the successful treatment of this complication is believed to be the abatement of inflammation. Leukotriene antagonists have emerged recently as effective prophylactic agents for reactive airway diseases. Anecdotal reports have indicated that zafirlukast and montelukast effectively reverse capsular contracture. The authors investigated whether capsular contracture varies significantly over time after zafirlukast therapy by studying 20 women who had breast prostheses implanted and then experienced the development of capsular contracture. The results suggest that capsular contracture responds favorably to treatment with zafirlukast. The findings indicate that zafirlukast may reduce pain and breast capsule distortion for patients with long-standing contracture who either are not surgical candidates or do not wish to undergo surgery.

Adult↗
PubMed2004

Incidence of ankle contracture after moderate to severe acquired brain injury.

OBJECTIVE: To examine an adult population undergoing rehabilitation after brain injury to determine the incidence of ankle contracture and factors contributing to the development of this deformity. DESIGN: Descriptive study SETTING: Specialist inpatient neurosurgical rehabilitation unit in Australia. PARTICIPANTS: Patients (N=105) admitted with a new diagnosis of moderate to severe brain injury over a 12-month period. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Maximal ankle dorsiflexion range and the presence of abnormal muscle tone affecting the lower limb(s) were evaluated at weekly intervals. Ankle contracture was defined as maximal passive range of less than 0 degrees dorsiflexion with the knee in extension. Patients were grouped into 3 muscle tone categories: normal, predominantly spastic, or predominantly dystonic. Age, sex, mechanism and severity of brain injury, time to onset of ankle contracture, total length of hospital stay, and discharge mobility status data were also recorded. RESULTS: Muscle tone was designated as normal in 68 (64.7%), as spastic in 14 (13.3%), and as dystonic in 23 (21.9%) patients. The incidence of ankle contracture was 16.2% (17/105 cases). Ankle deformity correlated closely with muscle tone category. Of 23 cases with dystonic muscle overactivity, 17 developed contracture at some point between 1 and 16 weeks after brain injury, although no subject with normal tone or spasticity developed the deformity. There was a weak association between the severity of brain injury and development of ankle contracture. CONCLUSIONS: The incidence of ankle contracture was much lower than previously reported. Dystonic overactivity of the plantarflexor and invertor muscles is a major predisposing factor to ankle contracture.

Activities of Daily Living↗
PubMed2006

Capsular contracture around saline-filled and textured subcutaneously-placed implants in irradiated and non-irradiated breast cancer patients: five years of monitoring of a prospective trial.

One hundred and seven breast cancer patients underwent subcutaneous mastectomy and immediate reconstruction with a subcutaneously-placed, round, saline-filled prosthesis with a textured surface. The primary aim of this prospective study was to determine the frequency of capsular contracture in both irradiated and non-irradiated breasts after this operation. Two different types of round implants with different pore sizes on their textured surfaces, Siltex and Microcell, were randomly chosen. Twenty-four patients received radiotherapy within the first year following the operation. Capsular contracture was measured by the Baker/Palmer classification and by applanation tonometry at regular intervals for 5 years or as long as the patients lived (median 60 months). Twenty-two patients (20.6%) developed capsular contracture, defined as Baker three or four. Sixteen of those were reoperated, 15 with open capsulotomy with or without implant exchange, one with closed compression capsulotomy, and monitored thereafter for 5 years or until death (median 60 months). All 107 patients could be monitored for 2 years, while 87 reported for the 5-year follow-up. The rate of capsular contracture was significantly higher (p=0.01) for irradiated breasts than for non-irradiated ones, 41.7 and 14.5%, respectively. It was slightly higher (p<0.05) for large-pore implants than for those with smaller (and more numerous) pores. There was a good correlation between the two different methods for measuring capsular contracture. None of the 16 reoperated patients had a recurrence of capsular contracture within 5 years. The results indicate a high rate of capsular contracture after this operation, especially when followed by radiation. However, a fairly simple procedure to treat capsular contracture seems to give good long-term results.

Adult↗
PubMed2006

The use of external skeletal fixation to facilitate the surgical release of wrist flexion and thumb web space contractures.

PURPOSE: To evaluate the use of external fixation as a splint to keep the hand in the desired position after simultaneous joint and soft-tissue release in a single stage for treatment of first web space and wrist contractures. METHODS: Six first web space adduction and 7 wrist flexion contractures were released surgically. All patients had prior unsuccessful surgery. After surgical release of the contracture and capsulotomy, external fixator pins were inserted into the first and second metacarpals to maintain thumb abduction and into the radius and second metacarpal to maintain wrist extension, followed by skin grafting. External fixation was followed by splinting. Results were based on persistence of contracture release, rate of complications, and functional outcome. RESULTS: Before surgery, the thumbs were contracted at an average of 0 degrees of adduction with no range of motion, and wrists were contracted between 85 degrees to 100 degrees of flexion. The duration of contracture and number of prior surgeries did not influence the amount of release obtained during the surgery. After 7 months to 7 years of follow-up of first web space contractures, the thumb was in an average of 55 degrees of palmar abduction. Patients were able to oppose and fully adduct. At long-term follow-up examinations of the wrist contractures, patients had the wrist in the neutral position (0 degrees) in the resting state, with active extension ranging between 5 degrees and 15 degrees and flexion ranging between 35 degrees and 45 degrees . In 1 patient the wrist was at 45 degrees of flexion in the resting state with an arc of motion of 20 degrees . In 1 patient the wrist contracted back to the preoperative position, requiring another surgery. All patients experienced increased activity and improvement in grasping objects at 6-month follow-up evaluations. Complications included 3 pin site infections, 1 severe discomfort after 6 weeks, and 1 median nerve compression. All were treated successfully. CONCLUSIONS: External fixation can be used to maintain position in cases of first web space and wrist flexion contractures after surgical release, especially in patients for whom standard methods have failed. It is safe, efficacious, and well tolerated. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Cicatrix↗
PubMed2003

Double reverse V-Y-plasty in postburn scar contractures: a new modification of V-Y-plasty.

UNLABELLED: Several techniques have been defined to use in surgical treatment of postburn scar contractures. However, distal flap necrosis is frequently seen since most of these techniques require random-pattern flaps and there is often poor vascular supply to scar tissue. In the Z-plasty, V-Y-plasty and their analogues, excess tissue requires excision of the dog-ear. A new modification of V-Y-plasty, called "double reverse V-Y-plasty", is discussed. Nineteen postburn scar contractures were successfully treated with double reverse V-Y-plasty. The postoperative results represent the versatility of this technique in the surgical treatment of postburn scar contractures, especially neck and extremities. There was no distal flap necrosis. Double reverse V-Y-plasty is effective and alternative to the current techniques in surgical treatment of every kind of postburn scar contractures with one or more contracture lines. It does not need any surgical knack. ADVANTAGES: (i) double reverse V-Y-plasty is safely useful, when skin tension across the contracture line is too great to use any local flaps; (ii) when superficial scarring is localized in the contracture site, it is superior to other local flaps because of rich vascularity and mobility; (iii) double reverse V-Y-plasty is advised to the inexperienced surgeon, since it is easy to use; (iv) color and texture matches are cosmetically acceptable, and the resultant contracture is as much as with other techniques; (v) there is no necessity to use excision of the dog-ear; (vi) it can be utilized under local anesthesia almost in all cases; and (vii) it requires a shorter period of operation, and hospitalization.

Adolescent↗
PubMed1987

Classification and treatment of postburn proximal interphalangeal joint flexion contractures in children.

Two hundred and sixty-four surgically treated proximal interphalangeal joint flexion contractures in children were reviewed. A classification system on the basis of contracture severity was devised to assess the efficacy of treatment. Contracture severity was determined from preoperative radiographs and physical examination. Eighty-eight percent of the digits were successfully treated (postoperative contracture less than 20 degrees). Unsatisfactory results (12% of digits) were directly proportional to the severity of the contracture and tended to occur in older children with large total body surface burns. The time interval between burn and contracture release did not correlate with contracture severity or therapeutic failure. The most common cause of an unsatisfactory result was failure to fully release the contracture.

Burns↗
PubMed2002

[Preoperative Intermittent Pneumatic Soft-Tissue Distraction in Patients with severe Dupuytren's Contracture].

PURPOSE: Evaluation of the outcome of preoperative intermittent pneumatic soft tissue distraction (IPD) in patients with severe contractures in Dupuytren's disease with special regards on recurrent deformities. METHOD: In a prospective study, nine patients with Dupuytren's contracture grade III and IV according to the classification of Tubiana were treated with a preoperative intermittent soft-tissue distraction using a pneumatic extension device followed by a standardized operative correction and follow-up program. Sixteen fingers were involved: grade I and II four fingers, grade III and IV twelve fingers. Nine fingers - grade III and IV seven fingers - in six patients had a recurrent deformity. RESULTS: The preoperative reduction of contracture simplifies the surgical treatment. Preoperatively using the IPD, the flexion contracture was reduced between 5 and 60 degrees. With an average of 29 (10 to 60) degrees, the improvement was greater in fingers with severe contracture (grade III and IV according to Tubiana) than in fingers with a minor contracture averaging 10 (5 to 25) degrees. In fingers with recurrent deformity, the reduction of the flexion contracture averaged 27 (5 to 60) degrees. There were no complications leading to break off of the distraction. CONCLUSION: The intermittent pneumatic distraction is a good alternative to the method introduced by Messina for preoperative soft-tissue distraction in patients with severe Dupuytren's contracture.

Aged↗
PubMedDate not supplied

Alterations in functional movement after axillary burn scar contracture: a motion analysis study.

Children with axillary burns often develop scar contractures that restrict shoulder movement. Objective data on functional movement patterns after contracture formation is sparse. The purpose of this study was to determine how axillary contractures affect shoulder movement during activities of daily living (ADLs). This was a prospective study of children with axillary contractures scheduled for surgical release. Three-dimensional upper extremity kinematic analysis was used to assess shoulder, elbow, and trunk motion during two ADLs: high reach and hand to back pocket. Results were compared with a pool of 49 normal age-matched controls. Eleven children with axillary contractures were compared with controls. During high reach, significant decreases in shoulder flexion, shoulder internal rotation, arm pronation, and trunk extension occurred. Elbow flexion increased significantly. In the hand to back pocket task, shoulder extension and elbow flexion decreased and shoulder abduction increased. Axillary contractures result in quantifiable movement changes during ADLs. Aggressive rehabilitation is required to prevent contracture formation. Three-dimensional motion analysis is a unique tool for the quantification of functional limitations and provides an objective method to evaluate treatment efficacy in patients with axillary contractures.

Activities of Daily Living↗
PubMed2006

A rabbit model for capsular contracture: development and clinical implications.

BACKGROUND: Capsular contracture remains one of the most common complications involving aesthetic and reconstructive breast surgery; however, its cause, prevention, and treatment remain to be fully elucidated. Presently, there is no accurate and reproducible pathologic in vitro or in vivo model examining capsular contracture. The purpose of this study was to establish an effective pathologic capsular contracture animal model that mimics the formation of capsular contracture response in humans. METHODS: New Zealand White rabbits (n = 32) were subdivided into experimental (n = 16) and control groups (n = 16). Each subgroup underwent placement of smooth saline mini implants (30 cc) beneath the panniculus carnosus in the dorsal region of the back. In addition, the experimental group underwent instillation of fibrin glue into the implant pocket as a capsular contracture-inducing agent. Rabbits were euthanized from 2 to 8 weeks after the procedure. Before the animals were euthanized, each implant was serially inflated with saline and a pressure-volume curve was developed using a Stryker device to assess the degree of contracture. Representative capsule samples were collected and histologically examined. Normal and contracted human capsular tissue samples were also collected from patients undergoing breast implant revision and replacement procedures. Tissue samples were assessed histologically. RESULTS: Pressure-volume curves demonstrated a statistically significantly increased intracapsular pressure in the experimental group compared with the control group. The experimental subgroup had thicker, less transparent capsules than the control group. Histologic evaluation of the rabbit capsule was similar to that of the human capsule for the control and experimental subgroups. CONCLUSIONS: The authors conclude that pathologic capsular contracture can be reliably induced in the rabbit. This animal model provides the framework for future investigations testing the effects of various systemic or local agents on reduction of capsular contracture.

Animals↗
PubMed2006

Determination of serum fibrosis indexes in patients with capsular contracture after augmentation with smooth silicone gel implants.

BACKGROUND: Several studies have confirmed a correlation between the concentration of serum hyaluronan and progressive fibrotic disorders such as liver cirrhosis. The aim of this study was to explore the relationship between serum hyaluronan levels and capsular contracture after aesthetic breast augmentation. METHODS: The study included 25 female patients (average age, 40 +/- 12 years) with capsular contracture after cosmetic breast augmentation with smooth silicone gel implants (Mentor, Santa Barbara, Calif.). The implants were placed in a submuscular position through an inframammary fold incision. The implant removals were prompted by development of capsular fibrosis (Baker grades I through IV). Samples of capsular tissue were obtained from all patients for standard histologic and immunohistochemical analysis. Blood samples were drawn from all patients immediately before operation. Sera from 20 healthy female patients (average age, 34 +/- 9 years) were used as control. RESULTS: : Capsular tissue revealed significantly higher thickness in patients with grade III/IV contracture than in women with grade II contracture, according to Baker's classification. There was a moderate (n = 15) or severe (n = 10) chronic inflammatory reaction in the capsules around the implants. Fibroblasts, fibroblast-like cells, and macrophages represented the major cell populations found within the fibrous capsules, along with scattered polymorphonuclear leukocytes, lymphocytes, plasma cells, and mast cells. In addition, activated CD4+ cells were detected. An inner layer with synovia-like metaplasia and multinucleated giant cells was found. There was a significantly higher level (p < 0.05) of hyaluronan serum concentration in patients with capsular contracture (26 +/- 14 microg/liter) compared with control subjects (12 +/- 6 microg/liter). There was a positive correlation between the grade of capsular contracture (Baker grades I through IV) and the hyaluronan serum concentration (Baker grade II, 15 +/- 3 microg/liter; Baker grade III, 34 +/- 13 microg/liter; Baker grade IV, 42 +/- 11 microg/liter) (r = 0.73; p < 0.05). CONCLUSIONS: Serum hyaluronan levels were significantly elevated in patients with capsular contracture after breast augmentation, and there was a positive correlation with stage of capsular contracture. Further study is necessary to determine whether hyaluronan might be useful as a predictor for the development and progress of capsular fibrosis.

Adult↗
PubMed1995

Contractures and loss of function in patients with Alzheimer's disease.

OBJECTIVE: To investigate the prevalence of contractures in patients with Alzheimer's disease and to assess possible associations between contractures and cognitive and functional decline in Alzheimer's disease. DESIGN: Case series. SETTING: Subjects from an outpatient, university-based, dementia research center, followed, when necessary, into residential home and nursing home settings. PATIENTS: A consecutive sample of 161 patients (48 men, 113 women; mean age 75.3 +/- 8.6 years) with a clinical diagnosis of probable Alzheimer's disease and with deficits in basic activities of daily living or more severe functional impairment. MAIN OUTCOME MEASURES: For cognition, the Mini-Mental State Examination (MMSE); for functioning, the Functional Assessment Staging Scale (FAST); contracture is defined as a decrease of 50% or more of the normal passive range of motion of the joint. RESULTS: Prevalence of contractures was correlated highly with degree of functional impairment (r = .70, P < .001). More than three quarters of patients who had lost the ability to walk manifested contractures; however, contractures were found in fewer than 11% of all ambulatory patients examined. When present, contractures involved more than one extremity in 97% of cases and involved all four extremities in more than two-thirds of patients. CONCLUSION: Joint contractures are very common in the severe stages of Alzheimer's disease. More than a quarter of a million institutionalized residents in US nursing homes are likely to be afflicted by this potentially painful and disfiguring condition. Possible pathophysiology and contributing factors and possible means of intervention for this major source of disability are discussed.

Activities of Daily Living↗
PubMed2002

Effect of pregnancy on joint contracture in the rat knee.

As there is evidence that ligamentous laxity is affected by the female hormones, we hypothesized that hormonal changes occurring during pregnancy could have a therapeutic role in preventing the development of a joint contracture. Knee joint contractures were created in pregnant and nonpregnant rats. After 2 wk of immobilization, the degree of contracture was measured with structural properties of the medial collateral and anterior cruciate ligaments and the pubic symphysis. Although not statistically significant, there was a general trend toward reduced contracture in pregnant compared with nonpregnant rats. Cutting the posterior capsule significantly decreased contracture for both the pregnant and nonpregnant groups, confirming the contribution of capsular structures to contracture. Ultimate loads of the medial collateral and anterior cruciate ligaments significantly decreased after immobilization compared with control, but there was no significant effect due to pregnancy. Stiffness and ultimate load of the pubic symphysis were not significantly different between pregnant and nonpregnant groups. The trend toward reduced contracture with pregnancy points toward a possible therapeutic role for female hormones in the prevention of postoperative and/or posttraumatic joint contracture.

Animals↗
PubMed1992

An insight into Dupuytren's contracture.

Dupuytren's contracture is a deforming, fibrotic condition of the palmar fascia which has confounded clinicians and scientists since the early descriptions by Guillaume Dupuytren in 1831. It predominantly affects elderly, male caucasians, has a hereditary predisposition and has strong associations with diabetes, alcohol consumption, cigarette smoking and HIV infection. The major morphological features are an increase in fibroblasts, particularly around narrowed fibroblasts; a finding consistent with localised ischaemia. During ischaemia, adenosine triphosphate (ATP) is converted to hypoxanthine and xanthine, and endothelial xanthine dehydrogenase to xanthine oxidase (alcohol also mediates this change, a finding of particular relevance given the association of Dupuytren's contracture with alcohol intake). Xanthine oxidase catalyses the oxidation of hypoxanthine to xanthine and uric acid with the release of superoxide free radicals (O2-), hydrogen peroxide (H2O2) and hydroxyl radicals (OH.). These free radicals are highly reactive, with half-lives in the order of milliseconds and are toxic in high concentrations. A potential for free radical generation in Dupuytren's contracture was elicited by finding a sixfold increase in hypoxanthine concentrations in Dupuytren's contracture compared with control palmar fascia. In vitro studies affirmed the toxic effects of oxygen free radicals to Dupuytren's contracture fibroblasts, but also showed that, at lower concentrations (concentrations similar to those likely to occur in Dupuytren's contracture), free radicals had a stimulatory effect on fibroblast proliferation. Cultured fibroblasts were found to release their own O2-. These endogenously released free radicals were also found to be important in fibroblast proliferation. The collagen changes of Dupuytren's contracture were examined. The results established that fibroblast origin was unimportant, but that inhibition of type I collagen production at high fibroblast density accounted for the increase in type III/I collagen ratios observed by previous investigators. These biochemical and morphological observations throw new light on Dupuytren's contracture. They suggest that age, genetic and environmental factors may contribute to micro vessel narrowing with consequent localised ischaemia and free radical generation. Endothelial xanthine oxidase derived free radicals may both damage the surrounding stroma and stimulate fibroblasts to proliferate. Proliferating fibroblasts lay down and contract collagen in lines of stress.Progressive fibroblast proliferation and deposition of collagen is likely to encourage further microvessel narrowing with a positive feedback effect consistent with the progressive nature of the condition.

Capillaries↗
PubMed2006

[Diagnosis and treatment of gluteal muscle contracture associated with unequal leg length caused by pelvis obliquity].

OBJECTIVE: To investigate the pathogenesis, diagnosis, and treatment of the gluteal muscle contracture associated with an unequal leg length caused by the pelvis obliquity (GMC-PO). METHODS: The retrospective analysis was made on the clinical features and the follow-up results in 132 patients who had been admitted from January 1990 to December 2004 for GMC-PO. Among them, 73 were male and 59 were female with a range in age from 5 to 26 years (average, 11 yr). All the patients were characterized by unsymmetrical contracture of the gluteal muscles, including unilateral and bilateral contracture. Of the patients, 89 had a clear limping and 78 had a clearly-unequal leg length. The X-ray examination revealed pelvis obliquity in 97 cases and an increased angle of the femur neck in 11 cases. The arc longitudinal incision was made into the posterolateral area nearby the greater trochanter and then lysis of the gluteal muscles was performed, combined with the skin traction of both legs and exercise training. RESULTS: Of the 132 patients with unequal gluteal muscle contracture before operation, 13 had a relative length difference of 0.5-1.5 cm between the 2 legs, 1 had a difference of 3.0 cm, and the remaining 118 patients had an equal leg length. Excellent and good results were achieved in 118 and 13 patients, respectively after the surgical release of the gluteal muscle contracture by the arc longitudinal incision into the posterolateral area nearby the greater trochanter, combined with postoperative skin traction and functional exercises. Only 1 patient had a poor result. The follow-up for 3 months to 14 years showed that the cure rate was as high as 99.2%. CONCLUSION: The gluteal muscle contracture associated with an unequal leg length caused by the pelvis obliquity is a result of the unequal gluteal muscle contracture between the 2 hips and it can be cured with a comprehensive therapeutic method including the surgical release of the gluteal muscle contracture by the are longitudinal incision into the posterolateral area nearby the greater trochanter, and postoperative skin traction as well as the functional exercise.

Adolescent↗
PubMed1993

Energetics of ionic contracture in rat-heart papillary muscles.

Energy dissipation and the bearing of tension during ionic contracture in myocardium may not result from one and the same process. To test this, comparative indirect and direct microcalorimetry determinations were made in non-perfused tissue-cell preparations under optimal oxygenation conditions (right papillary muscles, high-pO2 superfusion, 30 degrees C) before, during and after exposure to low-Na, high-K solutions. Over a 15-min contracture plus 45-min recovery cycle, both heat production rate (E), and the indirectly determined heat production rate (EO2) which is oxygen uptake multiplied by the overall energetic equivalent of O2 for nutrient oxidations, were constantly larger than basal rates. The two 60-min time integrals of this increase in metabolic rate were equal [30.3 +/- 3.7 and 31.0 +/- 3.9 (SE) J/g muscle wet weight (n = 9) for E and EO2 respectively]. During contracture however, E exceeded EO2 by 24% (4.7 +/- 1.7 J/g), and during the recovery period EO2 exceeded E by 21% (5.4 +/- 2.6 J/g). Whereas oxidative recovery of the energy lost by the preparation during 15-min contractures was complete, after longer contractures recovery did not occur or was incomplete. In keeping with the now prevalent idea that ion--namely Ca--transport activities are maintained foremost among cellular ATP-dependent processes and consume significant amounts of energy, the present finding that in a 15-min ionic contracture myocardium incurs not only some, but the maximum oxygen debt still compatible with complete oxidative recovery suggests that contracture tension is maintained at low energy cost, essentially by slow-cycling or "rigor" bridges as in hypoxic contractures, whereas heat is mainly related to intracellular calcium homeostasis.

Animals↗