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PubMed1987

Role of computed tomography in selecting patients for hindquarter amputation.

Nine patients with soft tissue sarcomas close to the pelvic girdle and one patient with a primary malignant bone tumour of the pelvis were referred for consideration of hindquarter amputation. Patients were considered unsuitable for hindquarter amputation on clinical grounds if malignant disease infiltrated into the perineum or across the sacro-iliac joint. If disease in the femoral triangle extended above the inguinal ligament the tumour's operability was seriously questioned. Buttock tumours which had passed through the greater sciatic notch to become palpable on pelvic examination were also considered likely to be inoperable. On computed tomographic (CT) examination, tumours were considered inoperable if the psoas muscle was involved above the inguinal ligament, or if malignant disease involved the sacro-iliac joint, sacrum or perineal structures. Soft tissue tumours of the buttock extending significantly through the greater sciatic notch were also considered likely to be inoperable. Five patients thought suitable for hindquarter amputation on clinical assessment had no excluding features on CT; four undergoing hindquarter amputation were proven on histological examination to have good clearance of their tumours. In another patient, considered suitable for hindquarter amputation on clinical grounds, CT suggested that en bloc wide excision of the tumour was feasible enabling the affected limb to be preserved. Four patients after clinical examination were considered unsuitable for hindquarter amputation and in all cases inoperability was confirmed by CT. CT complements clinical examination and provides an objective and reliable means of selecting patients for hindquarter amputation which should avoid unnecessary surgical exploration.

Adult↗

PubMed1993

Elastic properties of titin filaments demonstrated using a "freeze-break" technique.

A "freeze-break" technique (Trombitás, K.: Acta Biochim. Biophys. Hung. 6:419-427, 1971) and immunoelectron microscopy were used to study the elastic properties of titin filaments. Small bundles of freshly prepared rabbit psoas muscle fibers were quickly frozen and broken under liquid nitrogen to fracture sarcomeres in planes perpendicular to the filament axis, in each of various regions along the sarcomere. The still-frozen specimens were thawed during fixation to allow elastic filaments to retract. The broken specimens were then labelled with monoclonal anti-titin antibodies against an unique epitope in the I-band. The titin epitopes were normally positioned symmetrically about the Z-line. However, in sarcomeres broken at the A-I junction, the epitopes no longer remained symmetrical: the titin filaments in the broken half-sarcomere retracted, independently of the thin filaments, forming a dense band just near the Z-line. The retracted density apparently did not reach the Z-line; retraction stopped at the level of the so-called N1-line. In sarcomeres broken at the Z-line level, the titin filaments retracted in the opposite direction. In this case the titin epitope retracted all the way to the ends of the thick filaments. It appears then that titin molecules form elastic filaments that are independent of thin filaments in most of the I-band. Near the Z-line, however, the titin filaments either have an inelastic domain or associate firmly with the thin filaments at the N1-line level.

Actin Cytoskeleton↗

PubMed1991

Extrapulmonary inflammatory myofibroblastic pseudotumor: a potential cytologic trap in childhood.

A previously healthy 20-mo-old infant presented with a right leg limp and was discovered to have a palpable intra-abdominal mass. Radiographic studies showed the mass arising from the right psoas muscle. Preoperative clinical diagnosis was probable sarcoma. Percutaneous fine-needle aspiration biopsy of the mass was interpreted as a sarcoma based on the abundant cellularity of spindled shaped mesenchymal cells. Exploratory laparotomy showed the mass to be unresectable. Histologic and ultrastructural examination of biopsy fragments, however, revealed an inflammatory myofibroblastic pseudotumor. Radiographic follow-up showed a gradual disappearance of the mass. The infant was clinically well at a clinic visit one year following surgery. This case serves to illustrate the aspiration cytology of an uncommon benign tumor-like proliferation that, when located in an unusual anatomic site, has the potential to mislead the cytopathologist into a malignant interpretation.

Biopsy, Needle↗

PubMed2003

Vertical agarose gel electrophoresis and electroblotting of high-molecular-weight proteins.

The electrophoretic separation of high-molecular-weight proteins (> 500 kDa) using polyacrylamide is difficult because gels with a large enough pore size for adequate protein mobility are mechanically unstable. A 1% vertical sodium dodecyl sulfate (SDS)-agarose gel electrophoresis (VAGE) system has been developed that allows titin (a protein with the largest known SDS subunit size of 3000-4000 kDa) to migrate over 10 cm in a approximately 13 cm resolving gel. Such migration gives clear and reproducible separation of titin isoforms. Proteins ranging in size from myosin heavy chain ( approximately 220 kDa) up to titin can be resolved on this gel system. Electroblotting of these very large proteins was nearly 100% efficient. This VAGE system has revealed two titin size variants in rabbit psoas muscle, two N2BA bands in rabbit cardiac muscle, and species differences between titins from rat and rabbit muscle. Agarose electrophoresis should be the method of choice for separation and blotting of proteins with very large subunit sizes.

Animals↗

PubMedDate not supplied

Lumbar plexus neuropathy resulting from retroperitoneal hemorrhage.

A case of lumbar plexus neuropathy occurring in the setting of heparin therapy is reported. Documentation of the site of a retroperitoneal hematoma by CT scan was made prior to the full clinical evolution of lumbar plexus neuropathy resulting from a psoas-muscle hematoma. Two patterns of retroperitoneal bleeding and their respective clinical manifestations are discussed. Early diagnosis of these syndromes may allow for intervention before neurologic compromise is established.

Diagnosis, Differential↗

PubMedDate not supplied

Experimental corticosteroid myopathy: effect on myofibrillar ATPase activity and protein degradation.

Corticosteroid myopathy was studied in young, mature New Zealand white rabbits given daily injections of betamethasone (0.3 mg/kg body weight/day) for two weeks. Control rabbits were pair-fed and received saline injections. Bethamethasone treatment caused significant wasting of type 2 gluteus medius and psoas muscles but did not cause any atrophy of type 1 soleus and gluteus minimus muscles. The Mg2+- and Ca2+-activated myofibrillar ATPase activities of the corticosteroid-treated rabbits did not differ from controls despite a 30% reduction in muscle wet weight and pronounced reduction in cross-sectional area of fibers. SDS-polyacrylamide gel electrophoresis profiles of myofibrillar proteins did not differ quantitatively or qualitatively between experimental and control rabbits. Studies of net muscle protein degradation (using 3H-leucine) in betamethasone-treated and control rabbits indicate that both type 1 and type 2 muscle fiber proteins are degraded several times faster in the corticosteroid-treated group. This suggests that a compensatory mechanism exists for those type 1 and mixed fiber type muscles which have increased degradation but do not undergo wasting.

Adenosine Triphosphatases↗

PubMed2002

Partial unilateral ureteral obstruction in rats.

This review comprises an overview of the current knowledge on experimental partial unilateral ureteral obstruction (PUUO) and a summary of our latest original experimental PUUO studies in rats. Neonatal PUUO is the type of obstruction that is most often encountered in pediatric clinical practice. However, the pathogenesis of PUUO is still incompletely understood. Most of our knowledge on PUUO has been derived from experimental studies in a variety of animal models. Although progress has been made, the natural history of congenital hydronephrosis is still incompletely described. The effects on kidney functions of long-term urinary tract obstruction, especially PUUO, have been less intensively studied. Recently, we created models with mild and severe PUUO in young rats by embedding the upper one fourth or the upper two thirds of the left ureter into the psoas muscle, respectively. Thereafter, the technique was used to create mild and severe PUUO in newborn rats and magnetic resonance imaging studies showed that both mild and severe obstruction caused a time-dependent decrease in renal blood flow. Compensatory increase in total kidney volume and renal vein blood flow in contralateral non-obstructed kidneys was not detectable when functional deterioration in the partially obstructed kidneys was present. Finally, we investigated the dynamic changes in renal relative signal intensity (RSI) of gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) using magnetic resonance imaging in rats with partial, complete unilateral ureteral obstruction and sham-operated controls. The results showed that changes in Gd-DTPA RSI are compatible with the known physiological and anatomical changes in kidneys in response to ureteral obstruction and useful for distinguishing an obstructed from a non-obstructed collecting system and also for differentiating a partially obstructed from a completely obstructed collecting system.

Adult↗

PubMedDate not supplied

Differential diagnosis of solid renal tumors by MRI. Comparison of in situ relaxation times measured with a 0.1 T imager and histological findings.

The T1 and T2 of kidneys in 5 normal volunteers and 27 patients with renal tumors were evaluated preoperatively using a magnetic resonance imager with a 0.1 T resistive electromagnet, and the T1 and T2 of the renal tumors were compared with the pathological findings: (i) the T1 and T2 of the normal renal medulla were longer than those of the normal renal cortex and psoas muscle; (ii) both T1 and T2 of renal pelvic cancer (RPC) were shorter than those of renal cell cancer (RCC, p < 0.05); (iii) the T2 values of RPC were significantly shorter than those of renal medulla (p < 0.01); (iv) the T1 and T2 of the normal renal cortex of subjects < 50 years old were shorter than those of subjects > or = 50 years old (p < 0.05 and p < 0.01, respectively). These findings suggest that preoperative evaluation of the pathological findings of renal tumors may be possible by calculating the relaxation time using MRI under low magnetic field.

Adult↗

PubMed1992

Effects of clonidine-induced hypotension and dopamine-induced hypertension on blood flows in prostatic adenocarcinoma (Dunning R3327) and normal tissues.

In the present study it was investigated whether hypertension induced by dopamine or hypotension induced by clonidine could influence the relative blood distribution in a s.c. transplanted prostatic adenocarcinoma in relation to blood flow in normal tissues in rats. The blood flow was measured by using a radioactive microspheres technique. A bolus injection of 5 micrograms clonidine caused a decrease in the systemic blood pressure with 15-45 mm Hg, and blood flow to the central parts of the tumor, decreased with more than 50%. In the prostate, testes and ileo-psoas muscle a similar reaction was seen. During an infusion of 95-120 micrograms/kg/min dopamine, the blood pressure increased with 15-30 mm Hg, but the blood flow to the tumor was unchanged. However, in the testes and kidneys a decreased blood flow was observed. Moreover, mean blood flow to the central parts of the tumor decreased with increase in tumor size. The results further indicated that hyper- or hypotension or concomitantly given vasoactive drugs with the specific cancer treatment can have unwarranted effects on the distribution of cytotoxic drugs and oxygenation of the tumor.

Adenocarcinoma↗

PubMed2000

Duration of the hemodynamic effects of N(G)-nitro-L-arginine methyl ester in vivo.

The objective of this study was to quantify the duration of the hemodynamic activity of N(G)-nitro-l-arginine methyl ester (l-NAME) in a variety of different tissues following a single bolus injection of this nitric oxide synthase inhibitor to healthy rats. l-NAME (15 micromol x kg(-1)) was injected (ip) into rats to produce maximal inhibition of endothelial cell NOS. Animals were subsequently anesthetized and blood flow was quantified using the radioactive microsphere/reference organ technique. At 1 h following a single bolus injection of l-NAME blood flow was reduced to the entire gastrointestinal tract, pancreas, and liver. Three hours following l-NAME administration, blood flow to the stomach and upper small intestine had returned to pretreatment levels; however, blood flow to the jejunum, ileal-jejunal junction, and colon remained significantly reduced. Splenic blood flow was significantly reduced and hepatic arterial blood flow was further reduced at this time as well. After 6 h following l-NAME administration, blood flow in all organs had completely recovered to control levels. Although cardiac index and total peripheral resistance had also returned to preinjection values at this time, mean arterial pressure remained elevated at 6 h posttreatment. Blood flow to the brain, lungs, and psoas muscle were unaffected by l-NAME administration at any time point. Taken together, these data demonstrate a differential regulation of vascular tone by NO in different vascular beds and, depending upon the organ system in question, the vasoactive activity of l-NAME may last from 3 to 6 h following a single bolus injection of this NOS inhibitor.

Animals↗

PubMed1993

The mechanism of Ca(2+)-coordination in the EF-hand of TnC, by cassette mutagenesis.

Genetic engineering of TnC and skinned fiber physiology on rabbit psoas muscle are combined to study the mechanisms of Ca(2+)-binding in the EF-hand in TnC. Of the six coordinating positions (X,Y,Z,-Y,-X & -Z) for Ca(2+)-binding in the loop, the X position is invariably occupied by an aspartate, and the -Z position by a glutamate. X-ray analysis has indicated that both oxygen atoms of the beta-carboxylate in aspartate (in X) are extensively hydrogen bonded to other residues in the loop. When this aspartate in site II was replaced by a glutamate (gamma-carboxylate), Ca(2+)-binding was annihilated, and the mutant was unable to regulate force development in the fiber. Similarly, glutamate for aspartate exchange in the -Z position of site I also inactivated the site as well as its function in skinned fiber. Mutations in the Y position indicated that a glutamate was unacceptable in place of aspartate but that an asparagine was acceptable. The Ca(2+)-sensitivity with asparagine was also similar to that of the wild type. The study indicates a powerful approach for defining the physicochemical principles governing Ca-coordination and sensitivity in Ca-binding proteins. Furthermore, by comparison with findings on chemically synthesized peptides, the results show that behavior of the EF-hand in TnC is modified by quaternary structure of the molecule.

Amino Acid Sequence↗

PubMed1993

Inferences concerning crossbridges from work on insect muscle.

This paper presents a number of separate results concerning crossbridge attachment: [1] X-ray diffraction from live bumble bee flight muscle shows a set of layer lines distinct from that of relaxed Lethocerus, in which the apparent myosin helix is shorter than that of the actin. [2] Rigor crossbridges of Lethocerus are not rotatable by stretch. [3] Rabbit and Lethocerus fibres in rigor relaxed by ATP at -35 degrees C show evidence of non-rigor crossbridge attachment.

Animals↗

PubMed1998

X-ray diffraction studies of the cross-bridge intermediate states.

Two dimensional x-ray diffraction was obtained from skinned rabbit psoas muscle fibers. The goal is to correlate structures of the cross-bridge population with various intermediate states in the cross-bridge cycle by using nucleotides and their analogs. It was found that in a relaxed muscle in ATP containing solutions, cross-bridges are distributed in three populations in equilibrium: those detached from actin and ordered on the myosin helix, those that are detached and disordered, and those weakly attached to actin in random orientations. The distribution among the three populations is highly dependent on temperature. Those that are detached and yet ordered in a helical structure surrounding the myosin backbone are very likely in the M.ADP.Pi state, supporting an earlier suggestion by Wray (1987). It was also found that the attached cross-bridges with bound MgADP are structurally distinct from those without nucleotide, in agreement with one of our earlier findings by osmotic compression (Xu et al., 1993). Another finding of interest is that the analog AMP-PNP was found to be an ATP analog, rather than an ADP analog as it has been reported previously by many research groups.

Adenosine Triphosphate↗

PubMed1991

DNA fingerprinting: its application in forensic case work.

Forensic serology deals with cases of disputed paternity and criminal stains. The spectacular improvement using DNA-profiling is best demonstrated with cases of criminal stains where with the same ease as a suspect can be identified, an innocent person can be excluded. In cases with band-shifting, a statistical definition of a match applying Bayes theorem as a decision making tool seems mandatory since matching or non-matching cannot be treated as a binary event. Good postmortem DNA stability is found in brain cortex, lymph nodes and psoas muscle. DNA fingerprinting is also a perfect tool to investigate disputed identity of blood alcohol samples. In paternity cases, we recommend both multi locus and single locus probes in kinship cases, e.g. in mother-child-putative father cases as well as father-daughter and brother-sister incest cases, grandparent cases and two-men cases. For the biostatistical evaluation of SLP patterns the formal genetics for a system of multiple allelism is used and for multi locus probes the model of multiple diallelism is applicable.

Crime↗

PubMed1993

Active tension generation in isolated skeletal myofibrils.

Single or double myofibrils isolated from rabbit psoas muscle were suspended between a fine needle and an optical force transducer. By using a photodiode array, the length of every sarcomere along the specimen could be measured. Relaxed specimens exhibited uniform sarcomere lengths and their passive length-tension curve was comparable to that of larger specimens. Most specimens could be activated and relaxed four to five times before active force levels began to decline; some specimens lasted for 10-15 activation cycles. Active tension (20-22 degrees C) was reproducible from contraction to contraction. The contractile response was dependent on initial sarcomere length. If initially activated at sarcomere lengths of > or = 2.7 microns, one group of sarcomeres usually shortened to sarcomere lengths of 1.8-2.0 microns, while the remaining sarcomeres were stretched to longer lengths. Myofibrils that were carefully activated at shorter initial sarcomere lengths usually contracted homogeneously. Both homogeneous and inhomogeneous contractions produced high levels of active tension. Calcium sensitivity was found to be comparable to that in larger preparations; myofibrils immersed in pCa 6.0 solution generated 30% of maximal tension, while pCa 5.5-4.5 resulted in full activation. Active tension at full overlap of thick and thin filaments ranged from 0.34 to 0.94 N mm-2 (mean of 0.59 N mm-2 +/- 0.13 SD. n = 65). Even allowing for a maximum of 20% nonmyofibrillar space in skinned or intact muscle fibres, the mean tension generated by isolated myofibrils per cross-sectional area is higher than by fibre preparations.

Animals↗

PubMed1992

Metastatic potential of human renal cell carcinoma: experimental model using subrenal capsule implantation in athymic nude mice.

The aim of this study was to determine whether subrenal capsule (SRC) implantation is a suitable model for the study of the metastatic potential of our human renal cell carcinoma (HRCC) lines and to establish new sublines with enhanced metastatic ability. NMRI athymic nude mice 7-11 weeks old received SRC implantation of our HRCC lines RC43 and RC21. These lines were not metastatic when implanted s.c. Mice were killed after 4 or 8 weeks, or when moribund. With the RC43 cell line the success rate for implantation was 69%, with 89% of these showing metastases. The average volume of the implanted tumour fragments was 0.5 mm3 (range 0.28-0.7), the average volume at the primary site at the time of death was 9087 (9-32000) mm3. Metastases were found in lymph nodes, liver, spleen, peritoneum, psoas muscle, pancreas, diaphragm and skin. The average volume of the metastases was 4139 (0.5-9000) mm3. Growing cell lines were established in vivo and in vitro from one splenic, one peritoneal, one diaphragmatic, and one hepatic metastasis. These sublines have faster in vivo and slower in vitro growth rates than the parental lines. With the RC21 cell line the success rate for implantation was 56% and the metastatic rate 78%. The average volume of the implanted tumour was 0.8 mm3 (0.28-1.2), the average volume at the primary site at the time of death was 2685 mm3 (1.4-6534) and the average volume of metastases was 7.1 mm3 (0.5-37.5). Metastases were found in lymph nodes, lung and skin. No establishment was attempted for RC21 because of the small dimensions of these metastases.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1997

Abdominal actinomycosis: barium enema and computed tomography findings.

A case of abdominal actinomycosis is described in a woman with recurrent right lower abdominal pain and low-grade fever without history of appendectomy. Past history included the use of an intrauterine device (IUD) until 10 years before manifestation of these symptoms. We followed up the patient, via diagnostic imaging, for 7 months. On initial barium enema, a polypoid lesion was visualized at the bottom of the cecum and there was constriction of the sigmoid colon; the appendix was not seen. Seven months later, poor extension at the cecum, severe constriction in the sigmoid colon, and narrowing of the terminal ileum were also visualized. On computed tomography (CT), the lesion was initially localized only in the ileocecal region adjacent to the sigmoid colon. After 7 months, the lesion had infiltrated adjacent anatomic components and showed direct infiltration of the pelvic space. Differential diagnosis was difficult, as it was not obvious whether this was a pelvic abscess due to inflammation or appendiceal carcinoma. Laparotomy was performed. Macroscopically, the lesion was not limited to the ileocecal region, but involved the right ureter, tubes the Fallopian and ovary, bladder, psoas muscle, and abdominal wall. Pathology findings showed, chronic inflammatory tissue with evidence of actinomycosis. Although previous reports have described a lack of specific findings in this disease. When actinomycosis is suspected, CT is recommended to define its extent.

Abdominal Abscess↗

PubMed1990

Effect of ionic strength on crossbridge kinetics as studied by sinusoidal analysis, ATP hydrolysis rate and X-ray diffraction techniques in chemically skinned rabbit psoas fibres.

In order to identify which steps in the crossbridge are affected by changes in ionic strength, we studied the effect of ionic strength on the rate constants and magnitudes of three exponential processes, the ATP hydrolysis rate and isometric tension during maximal activation (pCa 4.52, 5 mM MgATP). Equatorial X-ray diffraction measurements were also carried out in both relaxing and rigor conditions to examine whether the distance between thick and thin filaments changes with ionic strength (range: 100-300 mM). All experiments were carried out at 20 degrees C and at pH 7.0 on chemically skinned rabbit psoas muscle fibres. Isometric tension and muscle stiffness declined significantly as the ionic strength was increased from 150 mM to 300 mM. The concomitant decrease in the ATP hydrolysis rate was much less than tension, resulting in a large increase in the tension cost. Three rate constants of exponential processes, deduced from sinusoidal analysis, did not change appreciably. The magnitude parameters of all three processes diminished as the ionic strength was increased. During relaxation the filament spacing increased by 5% when the ionic strength was increased from 150 mM to 300 mM. After rigor induction, the spacing did not change with ionic strength. We conclude that a change in ionic strength modifies the rapid equilibrium between the detached state and the 'weakly attached' state, and that this causes considerable effect on isometric tension. We also conclude that other steps in the crossbridge cycle are less sensitive to ionic strength, and that the lattice spacing change is unable to account for the considerable effect of ionic strength on isometric tension.

Adenosine Triphosphate↗