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In two out of three women breast reduction and reconstructive abdominoplasty relieve back pain and even sciatica. The biomechanical action of these techniques is analyzed. Further research consists of comparative measurements of intra-disc and spinal intra-muscular pressures between the pre- and post-operative periods.
We present an unusual observation actinomycosis involving muscles of the back and probably of one thigh in a patient with pulmonary lesions. The patient was alcoholic and a heavy smoker and his teeth were in very poor repair. Opportunity is taken to review the literature on the rare cases of muscular actinomycosis.
Insulin resistance plays an important role in the pathogenesis of human type 2 diabetes. In humans, a negative correlation between insulin sensitivity and intramyocellular lipid (IMCL) content has been shown; thus, IMCL becomes a marker for insulin resistance. Recently, magnetic resonance spectroscopy (MRS) has been established as a dependable method for selective detection and quantification of IMCL in humans. To validate the interrelation between insulin sensitivity and IMCL in an animal model of type 2 diabetes, we established volume selective (1)H-MRS at 7 Tesla to noninvasively assess IMCL in the rat. In male obese Zucker Diabetic Fatty rats and their lean littermates, IMCL levels were determined repeatedly over 4 months, and insulin sensitivity was measured by the euglycemic-hyperinsulinemic clamp method at 6-7 and at 22-24 weeks of age. A distinct relation between IMCL and insulin sensitivity was demonstrated as well as age dependence for both parameters. Rosiglitazone treatment caused a clear reduction of IMCL and hepatic fat despite increased body weight, and a marked improvement of insulin sensitivity. Thus, the insulin sensitizing properties of rosiglitazone were consistent with a redistribution of lipids from nonadipocytic (skeletal muscle, liver) back into fat tissue.
This study assessed low back and trapezius muscle activity in bus drivers, with or without recurrent low back pain (LBP), during the long term driving. In addition, low back and neck-shoulder pain intensities and fatigue were measured and the effect of low back support was observed. Also the possible source of LBP was attempted to assess by vibration pain provocation test and lumbar MRI. Forty bus drivers (recurrent LBP n = 25) participated in this study. Low back and neck-shoulder pain and subjective fatigue intensity was assessed by visual analogue scales (VAS) before and after driving. Lumbar paraspinal and trapezius muscle activation during driving was measured by surface EMG. Vibration pain provocation test was applied for all subjects. Average paraspinal myoelectric activity during driving was approximately 1% of MVC in both groups. Average trapezius myoelectric activity during driving was from 2 to 4% of MVC. Trapezius muscle activity was higher in back healthy drivers than in those with LBP. The low back support had no effect either on paraspinal or trapezius EMG activity. Low back and neck-shoulder fatigue increased during driving in both groups especially in those subjects with positive vibration pain provocation. The neck-shoulder pain and fatigue were more severe in drivers suffering from LBP. Low back support had no effect on low back and neck-shoulder subjective fatigue and neck-shoulder pain but tended to limit the LBP increase during driving. Paraspinal muscle loading in urban bus drivers was very limited and either LBP or ergonomic low back support had no effect on it. Trapezius muscle seemed to be less active in drivers suffering from recurrent LBP. Internal disc disruptions may expose to pain and fatigability during driving.
The aim of this study was to investigate whether the interstitial colloid osmotic pressure (COP(i)) of peritoneum is of importance for peritoneal fluid reabsorption during peritoneal dialysis (PD). For testing this hypothesis, a method to isolate interstitial fluid from the peritoneal membrane and to measure the interstitial COP(i) in the normal peritoneum and directly after the initiation of PD needed to be developed and validated. Eighteen female rats were anesthetized subcutaneously in the neck region with fentanyl-midazolam (1:1). Nylon wicks were implanted postmortem by means of a plastic catheter in the tissue just underneath the peritoneal surface. The characteristics of this fluid were compared with that isolated from wicks that were implanted in intermuscular spaces in hindlimb muscle and back subcutis. All wicks were removed after 20 min and centrifuged. The wick fluid was collected and analyzed in a colloid osmometer constructed for submicroliter samples, and interstitial fluid COP was compared with that of plasma. PD was initiated by injecting 20 ml of 3.86% glucose-containing PD fluid (Dianeal) into the peritoneal cavity, over a dwell time of 4 h. Control rats received no PD. The ratio of COP(i) to that of plasma (COP(p)) during control was 0.65 +/- 0.05 in peritoneum, 0.53 +/- 0.04 in muscle, and 0.59 +/- 0.05 in skin. After a PD dwell, the ratio was 0.29 +/- 0.03 in peritoneum, 0.54 +/- 0.08 in muscle, and 0.41 +/- 0.06 in skin. Thus, the COP ratio in peritoneum fell by 55% (P = 0.014) and in skin by 30% (P = 0.03), whereas the COP ratio in muscle was unchanged. The results suggest that acute PD results in a marked fall of the COP(i) in the peritoneal membrane, shifting the Starling equilibrium toward an absorptive state. The effect was restricted to the peritoneal membrane and, to some extent, the skin. It is speculated that the increase in peritoneal hydrostatic pressure after PD causes an increase in interstitial tissue volume, with primarily a dilution of interstitial colloids.
Magnetic resonance imaging was used to study the effect of different curvatures in the lumbar spine on lever arm lengths of the erector spinae musculature. Eleven subjects were instructed to simulate static lifts while lying supine in a magnetic resonance camera with the lumbar spine either in kyphosis or lordosis. A sagittal image of the spine was obtained to analyze the lumbosacral angle and to guide the imaging of transverse sections through each disc (L1/L2 to L5/S1). Images were analyzed for lever arm lengths of the erector spinae muscle (ES) and the erector spinae aponeurosis (ESA), the latter functioning as a tendon for superiorly positioned ES muscle portions. The lumbosacral angle (between superior surfaces of S1 and L4) averaged 44 degrees in the lordosed, 26 degrees in the kyphosed and 41 degrees in a neutral supine position. In lordosis, the lever arm lengths were significantly longer than in kyphosis for all levels, averaging 60-63 mm (ES) and 82-86 mm (ESA). The corresponding values for kyphosis were 49-57 mm (ES) and 67-77 mm (ESA), respectively. Thus, there was a considerable effect (10-24%) of lumbar curvature on lever arm lengths for the back extensor muscles. The change in leverage will affect the need for extensor muscle force and thus the magnitude of compression in the lumbar spine in loading situations such as lifting.
The purpose of this study was to test the hypothesis that older persons can minimize the reduction in physical fitness with aging if they start training before approximately 50 years of age, beyond which strength decline has been reported to become more pronounced. Maximal values for isometric strength, dynamic strength and speed of movement of the biceps brachii and quadriceps muscles, back-lift strength, and predicted oxygen uptake (VO2max = VO2max) were measured in 39 male subjects who were 60-68 years old. Four groups were studied: T26, T45, T56, and untrained. The T26 group had been training (jogging 10 km.day-1, 5 days.wk-1 at 10 km.h-1) since before their mid-thirties (mean 26 years), the T45 group since their forties (mean 45 years), the T56 group since their fifties (mean 56 years), and the untrained group had never taken part in any systematic training. Collectively, the T26 and T45 groups had significantly (p less than 0.05) higher values for muscle strength, speed of contraction, and VO2max than the T56 and/or untrained group(s). However, no differences were observed between the T26 and T45 groups. The results support a relation between the starting age of training and the age-dependent decline of physical fitness. Thus, the hypothesis is accepted.
OBJECTIVE: The purpose of this study was to correlate objective measurements of muscle fatigue in the lower back to the subject's own assessment of fatigue. DESIGN: Muscle fatigue in the lower back was assessed in healthy subjects using electromyography (EMG), endurance time and the Borg scale. BACKGROUND: Muscle fatigue, measured with EMG and endurance time, in the lower back, is significant for patients with pain in the lower back. METHODS: Fifty healthy subjects participated. EMG was detected from the lumbar extensor muscles during a modified Sørensen's test, an isometric contraction for the back extensors until exhaustion. During the test, subjects rated their subjective fatigue on a Borg CR-10 scale. RESULTS: Borg scale ratings correlated with endurance time (0.68) and EMG median- and mean power frequency slopes (0.41-0.50). At a Borg rating of 3, median- and mean power frequency and endurance time were reduced by 30%. At a Borg rating of 5, median- and mean power frequency and endurance time were reduced by 50%. At a Borg rating of 7, median- and mean power frequency and endurance time were reduced by 60-70%. CONCLUSIONS: Significant correlation between the Borg scale, EMG and endurance time suggests a close relationship between subjective and objective assessment of muscle fatigue.
Suxamethonium, like acetylcholine, causes contracture of the isolated rectus abdominis muscle of the frog, whereas laudexium antagonizes this effect. These actions may be used to assay both drugs with reasonable speed and fiducial limits, provided that changes in responsiveness of the preparation during the course of assay are met by suitable design and analysis. Small quantities of suxamethonium and laudexium may be assayed in certain body fluids.
STUDY DESIGN: A 5-year prospective study. OBJECTIVES: To investigate trunk muscle weakness as a risk factor for low back pain in asymptomatic volunteers. SUMMARY OF BACKGROUND DATA: Muscle strength has not been sufficiently studied as a risk factor for low back pain. METHODS: The study participants included 30 male and 37 female volunteers (mean age, 17 +/- 2 years), who neither reported nor had ever been treated for low back pain. Trunk muscle strength was measured isokinetically (60 degrees/sec), using the trunk extension and flexion and torso rotation units. The peak torques of the volunteers' extension, flexion, rightward rotation, and leftward rotation were measured, and the agonist/antagonist ratios were calculated as extension/flexion and left rotation/right rotation ratio. The volunteers then were followed prospectively for 5 years to determine the incidence of low back pain and were classified into a non-low back pain group (volunteers with no low back pain during the 5-year follow-up period) and a low back pain group (volunteers who experienced low back pain during this period). RESULTS: The low back pain group consisted of 8 male and 10 female volunteers. There were no significant differences between the non-low back pain group and the low back pain group regarding age, height, weight, the peak torque values, or the left rotation/right rotation ratio. However, the extension/flexion ratio of the low back pain group (men, 0.96 +/- 0.27; women, 0.77 +/- 0.19) demonstrated significantly lower values than that of the non-low back pain group (1.23 +/- 0.28 and 1.00 +/- 0.16 for men and women, respectively, P < 0.05). CONCLUSIONS: An imbalance in trunk muscle strength, i.e., lower extensor muscle strength than flexor muscle strength, might be one risk factor for low back pain.
OBJECTIVE: To inventory the current state of the art regarding the effectiveness of conservative treatment of acute low back pain. DESIGN: Systematic reviews. METHOD: The relevant literature from the period January 1966-September 1999 was retrieved via Medline, Embase, Psychlit and the Cochrane Library and via reference lists in the articles found. The methodological quality of the studies was assessed using criteria for internal validity. On the basis of the number of examinations, their quality and the consistency of the findings, conclusions were subdivided into four levels of strength of scientific evidence. RESULTS: Approximately two-thirds of the randomised trials in the field of back pain were of poor methodological quality. There was strong evidence that advice to stay active, non-steroidal anti-inflammatory drugs (NSAIDs) and muscle relaxants were effective in acute low back pain. There was also strong evidence that bed rest and specific exercises were not effective in acute low back pain. Strong evidence for effectiveness of many other commonly used interventions was lacking.
The authors report three cases of non-tuberculous epidural abscess. Presenting symptoms included lumbar back pain, muscle spasms, soft tIssue swelling, and neurological deficits in all three cases. MR imaging was helpful for diagnosis and showed involvement of perivertebral soft tissues and an epidural abscess of variable size. There was no significant involvement of intervertebral disks or vertebrae. Diagnosis was confirmed by bacteriologic exam. Clinical outcome was favourable with antibiotic treatment.
The possible existence of a phosphoenolpyruvate-dependent protein kinase activity in muscle first reported by Khandelwal et al. (FEBS Lett. 162, 127-132, 1983) was further examined in this study. [32P]Phosphoenolpyruvate was used to assay rabbit muscle extract that was first dialyzed and then passed over a gel filtration column. Fractions from the column were assayed for activity (as shown by counts incorporated into an acid-precipitable product), which was observed only when two distinct and resolved fractions were combined. The approximate masses of these two components, as estimated by nondenaturing gel filtration chromatography, were 30 and 160 kDa. The activity showed time and concentration dependence and was inactivated by heat and proteolysis. [gamma-32P]ATP could not substitute for [32P]phosphoenolpyruvate in the activity assays, nor was there evidence for the formation of ATP during the assays. Elution of the reaction mixture from a sizing column revealed several radioactive peaks. Other tissues (heart, kidney, liver, lung, spleen, and back skeletal muscle) from rabbit and rat were screened; the total activity was detected in all tissues examined, but was highest in the skeletal muscle of both species, with that from rabbit being twice that from rat.
OBJECTIVE: To discuss the clinical presentation of posterior limbus fractures and present a review of the literature on this topic. CLINICAL FEATURES: Patients presented with a combination of lower back pain, muscle spasm, diminished reflex responses, restricted motion and foot drop. In some cases, onset followed trauma; in others, it did not. INTERVENTION AND OUTCOME: Some patients required surgical intervention, whereas others underwent chiropractic manipulation and other conservative interventions. CONCLUSION: Posterior limbus fractures represent an avulsion of the ring apophysis from the vertebral body. Appropriate diagnostic work-up can help determine the presence of this condition. Management considerations are discussed.
Angiotensin II receptor blockers (ARBs) represent a new class of effective and well tolerated orally active antihypertensive agents. Recent clinical trials have shown the added benefits of ARBs in hypertensive patients (reduction in left ventricular hypertrophy, improvement in diastolic function, decrease in ventricular arrhythmias, reduction in microalbuminuria, and improvement in renal function), and cardioprotective effect in patients with heart failure. Several large long-term studies are in progress to assess the beneficial effects of ARBs on cardiac hypertrophy, renal function, and cardiovascular and cerebrovascular morbidity and mortality in hypertensive patients with or without diabetes mellitus, and the value of these drugs in patients with heart disease and diabetic nephropathy. The ARBs specifically block the interaction of angiotensin II at the AT1 receptor, thereby relaxing smooth muscle, increasing salt and water excretion, reducing plasma volume, and decreasing cellular hypertrophy. These agents exert their blood pressure-lowering effect mainly by reducing peripheral vascular resistance usually without a rise in heart rate. Most of the commercially available ARBs control blood pressure for 24 h after once daily dosing. Sustained efficacy of blood pressure control, without any evidence of tachyphylaxis, has been demonstrated after long-term administration (3 years) of some of the ARBs. The efficacy of ARBs is similar to that of thiazide diuretics, beta-blockers, angiotensin-converting enzyme inhibitors or calcium channel blockers in patients with similar degree of hypertension. Higher daily doses, dietary salt restriction, and concomitant diuretic or ACE inhibitor administration amplify the antihypertensive effect of ARBs. The ARBs have a low incidence of adverse effects (headache, upper respiratory infection, back pain, muscle cramps, fatigue and dizziness), even in the elderly patients. After the approval of losartan, five other ARBs (candesartan cilexetil, eprosartan, irbesartan, telmisartan, and valsartan) and three combinations with hydrochlorothiazide (irbesartan, losartan and valsartan) have been approved as antihypertensive agents, and some 28 compounds are in various stages of development. The ARBs are non-peptide compounds with varied structures; some (candesartan, losartan, irbesartan, and valsartan) have a common tetrazolo-biphenyl structure. Except for irbesartan, all active ARBs have a carboxylic acid group. Candesartan cilexetil is a prodrug, while losartan has a metabolite (EXP3174) which is more active than the parent drug. No other metabolites of ARBs contribute significantly to the antihypertensive effect. The variation in the molecular structure of the ARBs results in differences in the binding affinity to the receptor and pharmacokinetic profiles. The differences observed in lipid solubility, absorption/distribution, plasma protein binding, bioavailability, biotransformation, plasma half-life, and systemic elimination influence the time of onset, duration of action, and efficacy of the ARBs. On the basis of the daily mg dose, the antihypertensive potency of the ARBs follows the sequence: candesartan cilexetil > telmisartan approximately = losartan > irbesartan approximately = valsartan > eprosartan. After oral administration, the ARBs are rapidly absorbed (time for peak plasma levels = 0.5-4 h) but they have a wide range of bioavailability (from a low of 13% for eprosartan to a high of 60-80% for irbesartan); food does not influence the bioavailability, except for valsartan (a reduction of 40-50%) and eprosartan (increase). A limited dose-peak plasma levels/areas under the plasma level-time curve proportionality is observed for some of the ARBs. Most of these drugs have high plasma protein binding (95-100%); irbesartan has the lowest binding among the group (90%). The steady-state volumes of distribution vary from a low of 9 L (candesartan) to a high of 500 L (telmisartan). (ABSTRACT TRUNCATE
OBJECTIVES: To evaluate the effect of 1- or 3-monthly sequential combinations of estradiol valerate (E2V) and medroxyprogesterone acetate (MPA) on menopausal symptoms, bone density, muscle strength and lipid metabolism in postmenopausal women. METHODS: Changes in bone mineral density (BMD), isometric muscle strength, serum lipids and climacteric symptoms were evaluated in 78 women, 49-55 years of age, with a spontaneous menopause 0.5-3 years earlier. Treatment group I received 2 mg E2V tablets for 11 days, followed by 2 mg E2V + 10 mg MPA for 10 days and placebo for an additional 7 days; treatment group II received 2 mg E2V for 70 days, 2 mg E2V + 20 mg MPA for 14 days, and placebo for 7 days. The placebo group received placebo continuously for 24 months. Each group was further randomised to exercise and non-exercise subgroups. RESULTS: Both hormone regimens significantly reduced menopausal symptoms, and prevented equally well the decrease of BMD both in the lumbar spine and proximal femur. A positive effect of exercise on BMD was observed in the placebo group. No synergistic effect of exercise and estrogen on BMD could be shown. Both hormone regimens increased the isometric strength of back extensor muscles. Serum total and LDL cholesterol decreased during the first year with both estrogen regimens. CONCLUSIONS: Estrogen-progestin regimens were equally effective in the control of menopausal symptoms and preventing bone loss, increasing muscle strength and lowering serum cholesterol.
A new type of X-linked muscular dystrophy is described in a family in which 7 men had boyhood onset of progressive dystrophy involving muscles of the shoulder and back but not the calves or face. The scapula-back muscles are affected, but the calf muscles are normal. All patients are still able to walk. The oldest patient is now 37 years old. The muscular dystrophy has been specified by electromyography, pathologic tissue microscopic examination, electron microscopic study, and elevated CK. This type of muscular dystrophy has not been reported previously.
Gluteal activation and pelvic stability often are decreased in chronic low-back pain sufferers, but the importance of motor control and programming in treatment has not been fully evaluated. This study investigated whether gluteal muscles could be activated more effectively by stimulating the proprioceptive mechanism during walking. Labile support, through wearing "balance shoes," offered facilitation of cerebellovestibular circuits. Electromyographic recordings of gluteus maximus and medius in 15 healthy subjects were made during barefoot and balance shoes walking before and after 1 week of facilitation. Significant increases (P < 0.0002) in gluteal activity and significant decreases (P < 0.01) in time to 75% maximum contraction, demonstrated the value of sensorimotor elicitation of subconscious and automatic responses in muscles often weakened in back pain sufferers.