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PubMedDate not supplied

Computed tomography of ilio-psoas muscle tumors.

A retrospective evaluation of computed tomographic scans done at our institution showing psoas muscle tumors is presented. The anatomy of the psoas muscle along with a discussion of normal psoas anatomy which can be mistaken for tumor are reviewed. Primary muscle tumors along with metastatic, neurogenic, and lymphomatous tumors affecting the psoas muscle is discussed. The use of computed tomography for assessment of extent, origin, and structure of psoas muscle tumors is demonstrated.

Adult↗
PubMed2004

[A case of schwannoma in psoas muscle].

We report a case of schwannoma in psoas muscle, difficult to make a preoperative differential diagnosis from multilocular renal cyst in a 44-year-old woman. She complained of epigastric discomfort, and abdominal computerized tomography revealed a left multi-cystic renal tumor. Drip infusion pyelography showed the tumor displacing the left kidney superiorly, and pushing the left ureter medially. Magnetic resonance imaging demonstrated that the tumor structure was multilocular. At the operation, the tumor was observed in psoas muscle and was revealed as schwannoma in microscopic findings.

Adult↗
PubMed1993

The ultrasound appearance of the normal psoas muscle.

One hundred and forty-four psoas muscles in 72 subjects were scanned to study the normal ultrasound appearance. For the purpose of description the psoas was divided into three sections. Ten of the 432 sections could not be adequately seen on ultrasound. The psoas demonstrated hyperechoic striations on a hypoechoic background typical of muscle. In addition the upper section, from the origin of the muscle to the lower pole of the kidney, contained echogenic planes in 15 (10%) and the mid section, from the lower pole of kidney to iliac crest, demonstrated prominent echogenic planes and focal areas of increased and decreased echogenicity in 65 (46%). The lower section, from the iliac crest to fusion with the iliacus, demonstrated a single echogenic plane in 96 (70.5%) which was best seen running obliquely in the transverse plane and in 40 (29.5%) there were more complex echogenic planes or focal areas of increased or decreased echogenicity. The cause of the prominent echogenic plane in the lower section was not apparent in the anatomical literature and therefore cadaveric dissection of nine psoas muscles was performed which demonstrated that the echogenic plane was caused by intramuscular tendon fibres formed from the more cranial origins of the psoas. The psoas minor was not identified as a separate structure.

Adolescent↗
PubMedDate not supplied

Primary psoas muscle abscess diagnosed and treated during pregnancy: case report and literature review.

BACKGROUND: Primary psoas muscle abscess is rare and can be difficult to diagnose, particularly during pregnancy. CASE: To our knowledge, this is the first case of primary psoas muscle abscess diagnosed during pregnancy. Clinical investigation did not reveal any infection spreading from adjacent structures. Surgical drainage and simultaneous Cesarean delivery of the infant, combined with appropriate antibiotics, enabled a cure. CONCLUSION: The possibility of psoas muscle abscess should be taken into account when investigating lower back pain during pregnancy if conventional approaches are unsatisfactory.

Adult↗
PubMed1996

Cross-bridge binding to actin and force generation in skinned fibers of the rabbit psoas muscle in the presence of antibody fragments against the N-terminus of actin.

To assess the significance of the NH2-terminus of actin for cross-bridge action in muscle, skinned fibers of rabbit psoas muscle were equilibrated with Fab fragments of antibodies directed against the first seven N-terminal residues of actin. With the antibody fragment, active force is more inhibited than relaxed fiber stiffness, or stiffness in rigor or in the presence of magnesium pyrophosphate. Inhibition of stiffness in rigor or with magnesium pyrophosphate does not necessarily indicate involvement of the NH2-terminus of actin in strong cross bridge binding to actin but may simply result from the large size of the Fab. At high Fab concentrations, active force is essentially abolished, whereas stiffness is still detectible under all conditions. Thus, complete inhibition of active force apparently is not due to interference with cross-bridge binding to actin but may result from the Fab-mimicking inhibition of the thin filament by Troponin-1 binding to the NH2-terminus of actin at low Ca2+. However, although Troponin-1 is released from the NH2-terminus at high Ca2+, the Fab is not, thus disallowing force generation upon increase in Ca2+. These data are consistent with involvement of the NH2-terminus of actin in both weak cross-bridge binding to actin and Ca2+ regulation of the thin filament.

Actins↗
PubMed1998

Polyneural innervation in the psoas muscle of the developing rat.

Polyneural innervation was studied in the psoas muscle in developing rats from P4 till P25 and at adult age, with the combined silver-acetylcholinesterase technique. Nerve endings were counted, and end-plates were measured. These data were compared with such data in the human. The end of polyneural innervation in the rat (around P20) and in the human (around 12 weeks postterm age) in both cases coincides with a transformation in motor behavior and postural control. The rat's psoas muscle at early stages is less heavily innervated than this muscle in the human. Up to three axons per motor end-plate were counted at P4, but in the human up to five axons at 25 weeks of post menstrual age. This difference might be related to the lower percentage of type I muscle fibers in the rat.

Animals↗
PubMed1997

Temperature-induced structural changes in the myosin thick filament of skinned rabbit psoas muscle.

By using synchrotron radiation and an imaging plate for recording diffraction patterns, we have obtained high-resolution x-ray patterns from relaxed rabbit psoas muscle at temperatures ranging from 1 degree C to 30 degrees C. This allowed us to obtain intensity profiles of the first six myosin layer lines and apply a model-building approach for structural analysis. At temperatures 20 degrees C and higher, the layer lines are sharp with clearly defined maxima. Modeling based on the data obtained at 20 degrees C reveals that the average center of the cross-bridges is at 135 A from the center of the thick filament and both of the myosin heads appear to wrap around the backbone. At 10 degrees C and lower, the layer lines become very weak and diffuse scattering increases considerably. At 4 degrees C, the peak of the first layer line shifts toward the meridian from 0.0047 to 0.0038 A(-1) and decreases in intensity approximately by a factor of four compared to that at 20 degrees C, although the intensities of higher-order layer lines remain approximately 10-15% of the first layer line. Our modeling suggests that as the temperature is lowered from 20 degrees C to 4 degrees C the center of cross-bridges extends radially away from the center of the filament (135 A to 175 A). Furthermore, the fraction of helically ordered cross-bridges decreases at least by a factor of two, while the isotropic disorder (the temperature factor) remains approximately unchanged. Our results on the order/disordering effects of temperature are in general agreement with earlier results of Wray [Wray, J. 1987. Structure of relaxed myosin filaments in relation to nucleotide state in vertebrate skeletal muscle. J. Muscle Res. Cell Motil. 8:62a (Abstr.)] and Lowy et al. (Lowy, J., D. Popp, and A. A. Stewart. 1991. X-ray studies of order-disorder transitions in the myosin heads of skinned rabbit psoas muscles. Biophys. J. 60:812-824). and support Poulsen and Lowy's hypothesis of coexistence of ordered and disordered cross-bridge populations in muscle (Poulsen, F. R., and J. Lowy. 1983. Small angle scattering from myosin heads in relaxed and rigor frog skeletal muscle. Nature (Lond.). 303:146-152.). However, our results added new insights into the disordered population. Present modeling together with data analysis (Xu, S., S. Malinchik, Th. Kraft, B. Brenner, and L. C. Yu. 1997. X-ray diffraction studies of cross-bridges weakly bound to actin in relaxed skinned fibers of rabbit psoas muscle. Biophys. J. 73:000-000) indicate that in a relaxed muscle, cross-bridges are distributed in three populations: those that are ordered on the thick filament helix and those that are disordered; and within the disordered population, some cross-bridges are detached and some are weakly attached to actin. One critical conclusion of the present study is that the apparent order <--> disorder transition as a function of temperature is not due to an increase/decrease in thermal motion (temperature factor) for the entire population, but a redistribution of cross-bridges among the three populations. Changing the temperature leads to a change in the fraction of cross-bridges located on the helix, while changing the ionic strength at a given temperature affects the disordered population leading to a change in the relative fraction of cross-bridges detached from and weakly attached to actin. Since the redistribution is reversible, we suggest that there is an equilibrium among the three populations of cross-bridges.

Actin Cytoskeleton↗
PubMedDate not supplied

[The structure of thick filaments on longitudinal sections of rabbit psoas muscle].

By means of electron microscopy the longitudinal sections of chemically skinned fibres of rigorised rabbit psoas muscle have been examined at pH of rigorising solutions equal to 6, 7, 8 (I = 0.125) and ionic strengths equal to 0.04, 0.125, 0.34 (pH 7.0). It has been revealed that at pH 6.0 the bands of minor proteins localization in A-disks were seen very distinctly, while at pH 7.0 and I = 0.125 these bands can be revealed only by means of antibody labelling technique. At the ionic strength of 0.34 (pH 7.0) the periodicity of 14.3 nm in thick filaments was clearly observed, which was determined by packing of the myosin rods into the filament shaft and of the myosin heads (cross-bridges) on the filament surface. The number of cross-bridge rows in the filament equals 102. A new scheme of myosin cross-bridge distribution in thick filaments of rabbit psoas muscle has been suggested according to which two rows of cross-bridges at each end of a thick filament are absent. The filament length equals 1.64 +/- 0.01 micron. It has been shown that the length of thick filament as well as the structural organization of their end regions in rabbit psoas muscle and frog sartorius one are different.

Animals↗
PubMed1993

Effects of ionic strength on force transients induced by flash photolysis of caged ATP in covalently crosslinked rabbit psoas muscle fibers.

Single fibers from glycerinated rabbit psoas muscle were treated with 1-ethyl-3[3-(dimethylamino) propyl] carbodiimide (EDC), after rigor was induced, to crosslink myosin heads to actin. The optimally pre-stretched (approximately 1.8%), partially crosslinked fibers produce a large force when MgATP is depleted, and this force is abolished when MgATP is reintroduced, even in high ionic strength solution of 0.5 M (Tawada et al. 1989). We investigated the rate of force decay in the crosslinked, force-producing fibers using pulse photolysis of caged ATP (Goldman et al. 1984). The decay of force was fast, the rate of which depending both on the ionic strength and on the amount of ATP released (0.2-2.2 mM) with the second-order rate constant of 0.5-1 x 10(5) M-1s-1 at the ionic strength of 0.5 M. At high ionic strength (1-2M) force decayed at lower rate. At low ionic strength (0.1-0.2 M), however, force decayed more rapidly, but force redeveloped subsequently, which is probably caused by uncrosslinked myosin heads.

Adenosine Triphosphate↗
PubMed1976

Medial deviation of the ureters secondary to psoas muscle hypertrophy.

Bilateral medial deviation of mid and distal portions of the ureters can occur as a normal finding in patients with psoas muscle hypertrophy. Two groups of patients are presented, both composed of young, healthy males. In 13 patients, the distance between the ureters at the narrowest point averaged 3.7 cm. Psoas muscle hypertrophy was evident radiographically and confirmed by ultrasound. In 20 patients with normal psoas muscles, the average minimum distance between the ureters was 7.1 cm. The importance of this observation is to avoid overdiagnosis of retroperitoneal disease in this group of young, muscular men. The differential diagnosis and severe examples of this normal variant are presented.

Adult↗
PubMed1997

[Primary pyogenic abscess of the psoas muscle. Apropos of 5 cases].

The authors discuss the diagnostic and therapeutic aspects of primary pyogenic abscess of the psoas muscle based on a series of 5 cases. Five patients between the ages of 15 and 64 years (mean: 38.2 years) were admitted to the urology department between January 1994 and December 1996 with fever, abdominal pain and low back pain, and psoitis in 1 case. The mean delay to consultation was 42 days. Clinical examination revealed a painful mass in the lumbar region and flank in 5 cases. Leukocytosis was detected in 5 patients. Radiological examination demonstrated loss of the lateral border of the psoas in 4 cases. Ultrasonography showed an enlarged psoas muscle in every case with a hypoechoic mass in 2 cases and a heterogeneous mass in the other 3 cases. Computed tomography, performed in 2 patients, confirmed the ultrasound findings in 1 case and excluded the diagnosis of type IV hydatid cyst of the psoas muscle in the other patient. The abscess was evacuated by percutaneous drain in 1 patient requiring a second percutaneous drainage for reconstitution of the abscess. Surgical drainage was performed immediately in 3 patients and after failure of antibiotic treatment in 1 patient. The hospital stay did not exceed 7 days after surgical drainage, but was 25 days after the first percutaneous drainage and 20 days after the second percutaneous drainage. The authors emphasize the multiple advantages and efficacy of surgical drainage of psoas abscess.

Abdominal Pain↗
PubMed1984

Initiation of active contraction by photogeneration of adenosine-5'-triphosphate in rabbit psoas muscle fibres.

Mechanical and biochemical descriptions of the muscle cross-bridge cycle have been correlated. Skinned muscle fibres of rabbit psoas muscle in rigor were incubated in solutions containing approximately equal to 30 microM-Ca2+ ions and P3-1-(2-nitro)phenylethyladenosine-5'-triphosphate, 'caged ATP', an inert photolabile precursor of ATP. ATP was liberated from caged ATP within the fibres by pulses of 347 nm radiation from a frequency-doubled ruby laser. The mechanical responses of muscle fibres to the rapid increase of ATP concentration were monitored. Tension dropped briefly and then rose above the rigor value to the level characteristic of a steady active contraction. Liberation of ATP decreased in-phase stiffness (measured at 500 Hz) from the rigor level to a maintained value intermediate between rigor and relaxed values. Out-of-phase stiffness increased to a maintained level indicating a phase lead of tension with respect to imposed length oscillations. Rigor tension was varied prior to photolysis by slight alterations of fibre length. Tension traces starting at different rigor tensions converged to a common tension level at the same rate, whether or not Ca2+ was included in the medium. These data suggest that the rate of cross-bridge detachment by ATP from the rigor state is not influenced by Ca2+. Analysis of the tension records, in terms of sequential detachment and reattachment reactions, provided a measure of cross-bridge reattachment rate and an alternate measure of the detachment rate. Detachment from the rigor state was approximately proportional to the ATP concentration, with a second-order rate constant of at least 5 X 10(5) M-1 S-1. Reattachment with force generation had no detectable dependence on the concentration of ATP liberated by photolysis. A simple kinetic model of the cross-bridge cycle in terms of chemically defined intermediates was compatible with most of the experimental data. The ATP dependence of cross-bridge detachment, the kinetics of maintained cross-bridge reattachment in the presence of Ca2+, and transient reattachment and final relaxation in the absence of Ca2+ were explained. In this model, reversibility of cross-bridge attachment and the steps leading to force production allow the relatively high observed detachment rate to be accommodated with other data relating to active contraction. These data include the steady ATPase rate of active muscle fibres and the fewer attached cross-bridges in active contractions compared to rigor.

Actins↗
PubMed1987

Transient tension changes initiated by laser temperature jumps in rabbit psoas muscle fibres.

1. A technique was developed to generate 2-8 degrees C step temperature perturbations (T-jumps) in single muscle fibres to study the thermodynamics of muscle contraction. A solid-state pulsed holmium laser emitting at 2.065 microns heated the fibre and surrounding solution in approximately 150 mus. The signal from a 100 microns thermocouple fed back to a heating wire maintained the elevated temperature after the laser pulse. 2. Tension of glycerol-extracted muscle fibres from rabbit psoas muscle did not change significantly following T-jumps when the fibre was relaxed. 3. In rigor, tension decreased abruptly on heating indicating normal (not rubber-like) thermoelasticity. The thermoelastic coefficient (negative ratio of relative length change to relative temperature change) of the fibre was estimated to be -0.021 at sarcomere lengths of 2.5-2.8 microns. Rigor tension was constant after the temperature step and returned to the original value on recooling. 4. In maximal Ca2+ activation, tension transients initiated by T-jumps had several phases. An immediate tension decrease suggests that thermoelasticity during contraction is similar to that in rigor. Active tension then recovered to the value before the T-jump with an apparent rate constant of approximately 400 s-1 (at 10-20 degrees C). This rate constant did not have an appreciable dependence on the final temperature. Finally, tension increased exponentially to a new higher level with a rate constant of approximately 20 s-1 at 20 degrees C. This rate constant increased with temperature with a Q10 of 1.4. 5. At submaximal Ca2+ activation the tension rise was followed by a decay to below the value before the T-jump. This decline was expected from the temperature dependence of steady pCa-tension curves. The final tension decline occurred on the 1-5 s time scale. 6. The value and amplitude dependence of the rate constant for the quick recovery following T-jumps were similar to those of the quick recovery following length steps during active contractions. The enthalpy change associated with the quick tension recovery following temperature-step perturbations was estimated to be positive suggesting that the recovery process is an endothermic reaction. Slower reaction steps on the 10-30 ms timescale, as well as reactions corresponding to the quick recovery, may contribute to the cross-bridge power stroke.

Animals↗
PubMed2003

[Spontaneous hematoma of the iliac psoas muscle in chronic myeloid leukemia. A case report].

Spontaneous hematoma in the ilio-psoas muscle is an uncommon condition, usually observed as a complication of anticoagulation or hemophilia. Clinically, the onset is marked by violent pain in the territory of femoral nerve and/or psoitis. The diagnosis is confirmed by echography or CT-scan. The most serious complications are loss of self-sufficiency and neuro-muscular after-effect. Surgery is recommended in patients with neurological suffering, followed by early physiotherapy. We report the case of a 42-year-old man, with an ilio-psoas muscle hematoma, revealing chronic myeloid leukemia, without any hemostasis disorder.

Adult↗
PubMedDate not supplied

Gas in the psoas muscle secondary to an intravertebral vacuum cleft: CT characteristics.

Gas within the psoas muscle is usually due to primary or secondary infection necessitating aggressive therapy. We report a case of gas within the psoas muscle due to an intravertebral vacuum cleft, a benign manifestation of vertebral body necrosis. Identification of such a cleft in the proper clinical setting makes invasive evaluation unnecessary.

Emphysema↗
PubMed1993

State-dependent radial elasticity of attached cross-bridges in single skinned fibres of rabbit psoas muscle.

1. In a single skinned fibre of rabbit psoas muscle, upon attachment of cross bridges to actin in the presence of ADP or pyrophosphate (PPi), the separation between the contractile filaments, as determined by equatorial X-ray diffraction, is found to decrease, suggesting that force is generated in the radial direction. 2. The single muscle fibres were subjected to compression by 0-8% of dextran T500. The changes in lattice spacings by dextran compression were compared with changes induced by cross-bridge attachment to actin. Based on this comparison, the magnitude and the direction of the radial force generated by the attached cross-bridges were estimated. The radial cross-bridge force varied with filament separation, and the magnitude of the radial cross-bridge force reached as high as the maximal axial force produced during isometric contraction. 3. One key parameter of the radial elasticity, i.e. the equilibrium spacing where the radial force is zero, was found to depend on the ligand bound to the myosin head. In the presence of ADP, the equilibrium spacing was 36 nm. In the presence of MgPPi the equilibrium spacing shifted to 35 nm and Ca2+ had little effect on the equilibrium spacing. 4. The equilibrium spacing was independent of the fraction of cross-bridges attached to actin. The fraction of cross-bridges attached in rigor was modulated from 100% to close to 0% by adding up to 10 mM of ATP gamma S in the rigor solution. The lattice spacing remained at 38 nm, the equilibrium spacing for nucleotide-free cross-bridges at mu = 170 mM. 5. Radial force generated by cross-bridges in rigor at large lattice spacings (38 nm < or = d10 < or = 46 nm) appeared to vary linearly with lattice spacing. 6. The titration of ATP gamma S to fibres in rigor provided a correlation between the radial stiffness of the nucleotide-free cross-bridges and the equatorial intensities. The relation between the equatorial intensity ratio I11/I10 and radial stiffness appeared to be approximately linear. 7. The fibres under different conditions showed a wide range of radial stiffness, which was not proportional to the apparent axial stiffness of the fibre. If the apparent axial stiffness is a measure of the fraction of cross-bridges bound to actin, it follows that the radial elastic constant is state dependent; or vice versa.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenosine Diphosphate↗
PubMed1986

The reconstruction of myosin filaments in rabbit psoas muscle from solubilized myosin.

Using rabbit psoas muscle strips, A-bands with their myosin-containing thick filaments have been substantially reconstructed in situ (as judged by electron and light microscopy and by low-angle X-ray diffraction analysis) after prior solubilization of the myosin filaments in high ionic strength potassium phosphate solution. The maintenance of a very high local concentration of soluble myosin, by means of a closely apposed artificial semi-permeable membrane is necessary for reconstruction of full-length filaments. This reconstruction effect can be totally abolished by pre-glycerolation of the muscle, or (reversibly) by pre-depletion of Ca2+. Reconstruction at longer sarcomere lengths (greater than 2.6 micron) is anomalous, part-length 'stub filaments' being formed, with their stub tails projecting out from the I-Z-I lattice. A model is proposed to explain this reconstruction effect.

Animals↗
PubMed1997

[Hydatid cyst of the psoas muscle. Apropos of a case].

The authors report a rare case of hydatid cyst of the psoas muscle in a 28-year-old woman, operated for vertebrospinal hydatid cyst. The patient presented with a left iliac fossa mass. Ultrasonography and computed tomography contributed to the preoperative diagnosis, despite negative hydatid serology. A retroperitoneal approach by left lumbotomy with partial pericystectomy was performed. In the light of this case, the authors discuss the diagnostic and therapeutic problems raised by hydatid cyst of the psoas muscle.

Adult↗