ABSTRACT
INTRODUCTION: Cervical spine MRI with the neck in extension has been well described over the last 10 years, but its clinical value remains unknown. METHODS: We performed extension imaging in 60 patients in whom the initial neutral study showed borderline cord compression. Images were assessed using a previously validated grading system for cord compression. Multiple linear and area measurements were also obtained. Images were scored blindly and randomly. Inter- and intra-rater variability were determined in a subset of 20 cases. Independent clinical assessment utilised the Ranwat criteria. RESULTS: For most parameters inter/intra-observer variance of kappa/ICC > 0.6 was highly satisfactory. Standard MR was poor at discriminating between patients with and without myelopathy (ROC analysis, area under the curve (AUC), 0.52). This was considerably improved with extension imaging (AUC, 0.60), or by using the change in compression score between neutral and extension studies. Most measurements were not helpful; however, the ratio of cord area/CSF area at the level of maximum compression on extended images was the best discriminator (AUC, 0.71), as well as the presence of T2 change in cord substance (AUC, 0.68). CONCLUSION: This is the first study to demonstrate added clinical value utilising extension MRI. In this cohort of difficult patients, when there was no T2 signal change in the cord, the presence of clinical myelopathy could only be predicted by utilising the data from extension imaging.
Subject(s)
Algorithms , Cervical Vertebrae/pathology , Image Interpretation, Computer-Assisted/methods , Magnetic Resonance Imaging/methods , Neck/pathology , Spinal Cord Compression/pathology , Adult , Aged , Aged, 80 and over , Female , Humans , Image Enhancement/methods , Male , Middle Aged , Observer Variation , Reproducibility of Results , Sensitivity and Specificity , Young AdultABSTRACT
OBJECTIVES: Standard MRI of the cervical spine is performed in a different anatomical position to that utilised for traditional contrast myelography. Those well practised in myelography are familiar with the considerable changes in configuration of the bony and soft tissues of the cervical spine that may occur with changes in the degree of neck flexion and extension. We set out to compare the findings in a select group of patients with myeloradiculopathy who had undergone myelography and MRI in both standard and neck-extended positions. These findings were correlated with the clinical status. METHODS: 29 patients underwent myelography with CT (CTM) and MRI in neutral and neck-extended positions. The imaging was assessed for the degree of cord compression and neural foraminal narrowing, quantified using a simple grading scheme suitable for routine clinical practice. The degree of neck extension was assessed using an angular measurement. RESULTS: For both CTM and MRI, scanning with the neck extended significantly increases the severity of cord compression compared with the standard supine position, to a degree similar to that shown during conventional prone myelography. The degree of perceived cord compression is related to the degree of neck extension achieved. Correlation of standard MRI findings and the clinical level of radiculopathy is poor. This correlation improves when the neck is extended. CONCLUSIONS: The most appropriate position for routine MRI of the cervical spine in degenerative disease remains unknown, but in selected patients imaging with the neck extended may provide important additional information.
Subject(s)
Cervical Vertebrae , Magnetic Resonance Imaging/methods , Radiculopathy/diagnosis , Spinal Cord Compression/diagnosis , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Myelography/methods , Observer Variation , Prone Position , Retrospective Studies , Supine Position , Tomography, X-Ray ComputedABSTRACT
Singlet and triplet electronic excitation energies have been calculated for Ne, CH(2), C(2), N(2), and H(2)O using the Monte Carlo configuration interaction (CI) method. We find that excitation energies can be predicted to within a few tens of meV of full CI (FCI) results using expansions consisting of only a few thousand configuration state functions as compared to the O(10(8)) configurations occurring in the corresponding FCI expansions. The method provides a consistently accurate and balanced description of electronic excitations with accuracy for small molecular systems comparable to the equation-of-motion coupled cluster method with full triples.
ABSTRACT
ACES III is a newly written program in which the computationally demanding components of the computational chemistry code ACES II [J. F. Stanton et al., Int. J. Quantum Chem. 526, 879 (1992); [ACES II program system, University of Florida, 1994] have been redesigned and implemented in parallel. The high-level algorithms include Hartree-Fock (HF) self-consistent field (SCF), second-order many-body perturbation theory [MBPT(2)] energy, gradient, and Hessian, and coupled cluster singles, doubles, and perturbative triples [CCSD(T)] energy and gradient. For SCF, MBPT(2), and CCSD(T), both restricted HF and unrestricted HF reference wave functions are available. For MBPT(2) gradients and Hessians, a restricted open-shell HF reference is also supported. The methods are programed in a special language designed for the parallelization project. The language is called super instruction assembly language (SIAL). The design uses an extreme form of object-oriented programing. All compute intensive operations, such as tensor contractions and diagonalizations, all communication operations, and all input-output operations are handled by a parallel program written in C and FORTRAN 77. This parallel program, called the super instruction processor (SIP), interprets and executes the SIAL program. By separating the algorithmic complexity (in SIAL) from the complexities of execution on computer hardware (in SIP), a software system is created that allows for very effective optimization and tuning on different hardware architectures with quite manageable effort.
ABSTRACT
An unusual combination of primary cerebral lymphoma and meningioma occurring contiguously was encountered in a 71-year-old male patient. The possibility of two separate tumours was suspected radiologically and confirmed by histology. The association of primary lymphoma and meningioma is extremely rare. Following review of the literature, current evidence would suggest that the association is probably coincidental.
Subject(s)
Brain Neoplasms/diagnosis , Lymphoma, B-Cell/diagnosis , Meningeal Neoplasms/diagnosis , Meningioma/diagnosis , Neoplasms, Second Primary/diagnosis , Aged , Brain Neoplasms/pathology , Humans , Lymphoma, B-Cell/pathology , Magnetic Resonance Imaging , Male , Meningeal Neoplasms/pathology , Meningioma/pathology , Neoplasms, Second Primary/pathology , Tomography, X-Ray ComputedABSTRACT
INTRODUCTION: Posterior tibial translation in total knee replacement (TKR) could be one major factor for PE wear, delamination and loosening of the tibial component due to increased shear forces and component-to-bone interface stress. The aim of this study was to assess the posterior stability of two different designs of posterior cruciate ligament (PCL) substituting TKR. METHOD: In this non-randomised consecutive study 43 patients underwent TKR for primary osteoarthritis. Twenty-six patients in group FB received a deep-dished fixed-bearing Duracon TKR (Howmedica, Rutherford, NJ, USA) and 17 patients in group MB a deep-dished rotating mobile-bearing Duracon TKR. In both groups the PCL was resected. All patients had pre- and postoperative kneeling stress radiographs and were clinically evaluated with the Knee Society Score. Posterior tibial translation was measured by tracing a line along the posterior tibial cortex in relationship to the posterior edge of Blumensaat's line. RESULTS: The average follow-up was 13 months for group FB and 11 months for group MB. Both groups demonstrated a statistical significant increase of the mean posterior tibial translation on kneeling stress X-ray of 4.1 mm (group FB) (P < 0.001) and of 6.6 mm (group MB) (P < 0.001) compared to pre-operative. Group MB showed a significant higher posterior draw (P < 0.008). Clinical assessment using the Knee Society Score showed comparable short-term results. CONCLUSION: The deep-dished fixed-bearing TKR as well as the deep-dished rotating mobile-bearing TKR demonstrated significant posterior tibial translation on kneeling stress X-ray. It remains to be determined what amount of joint play is optimal for clinical function and to minimise shear forces and PE wear. Moreover the amount of posterior tibial translation was significantly higher with the mobile-bearing insert, which could be directly related to the asymmetric rotational mobility of the tibial insert. A long-term follow-up is necessary to investigate whether our findings correlate with the survival-rate of these specific implants.
Subject(s)
Knee Joint/physiopathology , Prosthesis Design , Aged, 80 and over , Biomechanical Phenomena , Female , Humans , Knee Joint/diagnostic imaging , Knee Prosthesis , Male , Middle Aged , Radiography , Stress, MechanicalABSTRACT
The aim of this study was to assess the posterior stability of two different designs of total knee replacement (TKR) with deep-dished mobile bearing (MB) implants using stress X-rays. In a prospective non-randomized consecutive study, 34 patients with primary osteoarthritis of the knee underwent TKR. In group A (17 knees), they received a MB insert with a Duracon prosthesis and in group B (18 knees), a Genesis prosthesis. In all cases the posterior cruciate ligament (PCL) was resected. All patients had pre- and post-operative kneeling X-rays and were clinically evaluated with the Knee Society Score. Measurements on the radiographs were taken by tracing a line along the posterior cortex of the tibia and then measuring the perpendicular distance to a point marked at the posterior corner of Blumensaat's line. The average follow up was 10.7 months for group A and 5.4 months for group B. No statistical difference could be found in terms of clinical results and pre- and post-operative kneeling X-rays between the two groups. In each group, all knees demonstrated a significant posterior tibial translation postoperatively compare to their pre-operative status (p<0.0001). There are advantages in resecting the PCL in TKR: mobile flexion gap, correction of fixed deformity, more flexibility to adjust the joint line. The use of a deep dished polyethylene (PE) insert provides stability and use of MB insert reduces PE wear whilst retaining congruity. Two designs of deep-dished MB inserts showed significant posterior tibial translation on stress X-rays. It remains to be determined what amount of laxity is optimal for clinical function and polyethylene longevity.
Subject(s)
Arthroplasty, Replacement, Knee , Knee Joint/diagnostic imaging , Knee Prosthesis , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Osteoarthritis, Knee/surgery , Outcome Assessment, Health Care , Posterior Cruciate Ligament/surgery , Prospective Studies , Prosthesis Design , Radiography , Stress, Mechanical , Weight-BearingABSTRACT
We recorded the total and 8-hourly post-operative drainage of 100 consecutive total knee replacements (33 cemented, 35 hybrid and 32 uncemented). The cemented, hybrid and uncemented prostheses had mean total drainage of 745, 1035 and 1220 ml, respectively. The difference in drainage between cemented and both hybrid and uncemented was statistically significant (P<0.05 and P<0.001). A significantly higher percentage of drainage occurred in the first 8-h period in the hybrid and uncemented groups. Total drainage in the cemented group was lower, but occurred more slowly, with a significantly higher percentage of drainage in the 17-48-h post-operative period when compared with the uncemented group (P<0.05). Within the cemented group, posterior-stabilised implants drained significantly more than those with an AP-lipped tibial insert (P<0.05). This information has implications for planning of blood product usage and timing of drain tube removal.
Subject(s)
Arthroplasty, Replacement, Knee/instrumentation , Arthroplasty, Replacement, Knee/methods , Bone Cements , Drainage , Postoperative Care , Anticoagulants/therapeutic use , Heparin, Low-Molecular-Weight/therapeutic use , Humans , Outcome Assessment, Health Care , Postoperative Hemorrhage , Prosthesis Design , TourniquetsSubject(s)
Leukemia, Lymphocytic, Chronic, B-Cell/diagnosis , Lymphoma, Large B-Cell, Diffuse/diagnosis , Lymphoma, Non-Hodgkin/diagnosis , Nose Neoplasms/diagnosis , Antibodies, Monoclonal/therapeutic use , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Bone Marrow Transplantation , Cyclophosphamide/therapeutic use , Doxorubicin/therapeutic use , Humans , Leukemia, Lymphocytic, Chronic, B-Cell/therapy , Lymphoma, Large B-Cell, Diffuse/therapy , Lymphoma, Non-Hodgkin/therapy , Male , Middle Aged , Nose Neoplasms/therapy , Prednisone/therapeutic use , Syndrome , Vincristine/therapeutic useABSTRACT
We found that light-induced Fe(III) reduction associated with the oxidation of a simple hydroxy-carboxylic acid (lactate) caused the formation of the AlO4Al12(OH)24(H2O)12 polycation ("Al13"). Initial conditions were a lactate:Al:Fe ratio of 1:0.76:0.11 in a partially neutralized solution. Base was added rapidly and no Al13 was detected in samples kept in the dark. With exposure to light, Fe(III) reduction was rapid and Fe(II) reached a maximum within 1 day. After the maximum, steady-state Fe(II) declined from 54% to 43% over eight days. During this same time period, the lactate concentration fell to 2% of the original, pH rose from 4.05 to 4.46, and the Al13 detectable by 27Al NMR increased to 2.3 mmol l(-1) (51% of the total solution Al). The formation of Al13 is attributed to the pH rise resulting from the removal of the organic acid buffer. Similar photo-induced chemical changes occur in natural waters and may promote the formation of Al13, conditions permitting.
Subject(s)
Aluminum/chemistry , Ferric Compounds/chemistry , Polyamines/chemistry , Environmental Pollutants , Hydrogen-Ion Concentration , Organic Chemicals , Oxidation-Reduction , Photochemistry , PolyelectrolytesSubject(s)
Anterior Cruciate Ligament Injuries , Bone Transplantation , Knee Injuries/surgery , Tendon Transfer , Anterior Cruciate Ligament/physiopathology , Anterior Cruciate Ligament/surgery , Biomechanical Phenomena , Humans , Knee Injuries/physiopathology , Postoperative Complications/physiopathology , Prosthesis Implantation , Tissue and Organ Harvesting , Transplantation, Autologous , Transplantation, HomologousABSTRACT
In the canine model of Duchenne muscular dystrophy in golden retrievers (GRMD), a point mutation within the splice acceptor site of intron 6 leads to deletion of exon 7 from the dystrophin mRNA, and the consequent frameshift causes early termination of translation. We have designed a DNA and RNA chimeric oligonucleotide to induce host cell mismatch repair mechanisms and correct the chromosomal mutation to wild type. Direct skeletal muscle injection of the chimeric oligonucleotide into the cranial tibialis compartment of a six-week-old affected male dog, and subsequent analysis of biopsy and necropsy samples, demonstrated in vivo repair of the GRMD mutation that was sustained for 48 weeks. Reverse transcription-polymerase chain reaction (RT-PCR) analysis of exons 5-10 demonstrated increasing levels of exon 7 inclusion with time. An isolated exon 7-specific dystrophin antibody confirmed synthesis of normal-sized dystrophin product and positive localization to the sarcolemma. Chromosomal repair in muscle tissue was confirmed by restriction fragment length polymorphism (RFLP)-PCR and sequencing the PCR product. This work provides evidence for the long-term repair of a specific dystrophin point mutation in muscle of a live animal using a chimeric oligonucleotide.
Subject(s)
DNA Repair , DNA/metabolism , Dystrophin/genetics , Oligonucleotides/therapeutic use , Point Mutation , RNA/metabolism , Animals , Base Sequence , Blotting, Western , Disease Models, Animal , Dogs , Epitope Mapping , Exons , Frameshift Mutation , Immunohistochemistry , Introns , Male , Molecular Sequence Data , Muscle, Skeletal/metabolism , Muscular Dystrophy, Duchenne/genetics , Muscular Dystrophy, Duchenne/therapy , Polymorphism, Restriction Fragment Length , Reverse Transcriptase Polymerase Chain Reaction , Sarcolemma , Sequence Homology, Nucleic Acid , TemperatureABSTRACT
Understanding of rapid disappearance of nitrite in natural waters and its impact on nitrogen natural cycling has remained limited. We found that NO2- disappeared rapidly in pH 3.2 aqueous Fe(III) solutions both in sunlight and in 356 nm light. Quantum yields of the NO2- loss at 356 nm were 0.049-0.14 for initial levels of 10-80 microns NO2- and 200 microns Fe(III). The NO2- loss (at 356 nm) followed apparent first-order kinetics. The rate constants were 1.3 x 10(-3) (40 microns NO2-) and 4.1 x 10(-4) s-1 (80 microns NO2-) for 100 microns Fe(III), and 2.3 x 10(-3) (40 microns NO2-) and 7.5 x 10(-4) s-1 (80 microns NO2(-1)) for 200 microns Fe(III) (t1/2 = 8.7, 27.9, 5.1, and 15.3 min, respectively). The rate constants were directly proportional to [Fe(III)]0 and inversely proportional to [NO2-]0. Agreement between the rate constants obtained experimentally and those calculated mechanistically supports the hypothesis that NO2- was oxidized to NO2 by .OH radicals from photolysis of FeOH2+ complexes, and at high [NO2-]0 (e.g., 80 microns) relative to [Fe(III)]0, hydrolysis of NO2 or N2O4 to form NO3- and NO2- could be significant. This study showed that light and Fe(III)-induced oxidation of NO2- (rate = approximately 10(-1)-10(-2) microns s-1) was more rapid than its direct photolysis (rate = approximately 10(-4) microns s-1), and the photolysis could be a significant source of .OH radicals only in cases where the Fe(III) level is much lower than the NO2- level ([Fe(III)]/[NO2-] < 1/80). This study suggests that the light and Fe(III)-induced oxidation of NO2- would be one potential important pathway responsible for the rapid transformation of NO2- in acidic surface waters, especially those affected by acid-mine drainage or volcanic activities. This study also may be of interest for modeling certain acidic atmospheric water environments.
Subject(s)
Iron , Nitrites/chemistry , Water Pollutants, Chemical , Hydrogen-Ion Concentration , Kinetics , Models, Chemical , Nitrites/radiation effects , Quantum Theory , Sunlight , Ultraviolet RaysSubject(s)
Dependovirus/genetics , Genetic Therapy/methods , Muscle, Skeletal/metabolism , Amino Acid Sequence , Animals , Base Sequence , Cells, Cultured , DNA, Viral/genetics , Gene Expression , Gene Targeting/methods , Genetic Vectors , Humans , Immunohistochemistry , Insulin/genetics , Molecular Sequence Data , Proinsulin/genetics , Transduction, GeneticABSTRACT
We report a prospective series evaluating the incidence and degree of tunnel widening in a well-matched series of patients receiving a hamstring or patella tendon graft for anterior cruciate ligament (ACL) deficiency. We correlated tunnel widening with clinical factors, knee scores, KT-1000 and isokinetic muscle strength to determine the clinical significance of this finding. Seventy-three patients at least 12 months post-ACL reconstruction were evaluated. Thirty-eight patients had received a doubled semitendinous and gracilis graft and 35 a bone-patella tendon-bone graft. All patients underwent a similar endoscopic procedure and accelerated postoperative rehabilitation. Tunnel widening was determined using standardized anteroposterior (AP) and lateral X-rays adjusted for magnification. A limited series of MRIs was performed to validate these measurements. There was a significant difference in the degree of tunnel widening between the two groups. The mean increase in femoral tunnel area in the hamstring group was 100.4% compared with a decrease of 25% in the patella tendon group (P = < 0.0001). In the tibial tunnel the mean increase in the hamstring group was 73.9% compared with a decrease of 2.1% in the patella tendon group (P = < 0.0001). The MRIs validated the plain film measurements. Tunnel widening did not correlate with the clinical findings, knee scores, KT-1000 or isokinetic muscle strength. Tunnel widening is marked in the hamstring group. Tunnel widening does not correlate with instability or a poor clinical outcome in the short term. The long-term implications of this finding are still to be determined.
Subject(s)
Anterior Cruciate Ligament/surgery , Knee Injuries/surgery , Knee Joint/diagnostic imaging , Muscle, Skeletal/transplantation , Postoperative Complications/diagnostic imaging , Tendons/transplantation , Adult , Anterior Cruciate Ligament Injuries , Arthroscopy , Endoscopy , Female , Follow-Up Studies , Humans , Knee Injuries/diagnostic imaging , Magnetic Resonance Imaging , Male , Patella , Prospective Studies , RadiographyABSTRACT
Two MRI strategies which have been reported to be effective in assessing cervical exit foramina, were prospectively compared with CT myelography in 20 patients with cervical radiculopathy. The first strategy utilized 3D T2* images, the second gadolinium enhanced 2D T1 images. Gadolinium (dimeglumine gadopentetate, Schering Ltd) enhanced images did not confer any benefit in the investigation of this condition, probably due to enhancement of herniated disc material and osteophytes adjacent to the neurocentral joint. Three-dimensional (3D) T2* white cerebrospinal fluid images had an accuracy approaching 90% for the diagnosis of foraminal encroachment, compared with a gold standard. MRI including a 3D T2* sequence is thus an acceptable primary investigation for cervical radiculopathy, but when the findings are incompatible with clinical symptomatology, CT myelography is still indicated.
Subject(s)
Magnetic Resonance Imaging/methods , Spinal Nerve Roots/pathology , Tomography, X-Ray Computed , Adult , Aged , Contrast Media , Female , Follow-Up Studies , Gadolinium DTPA , Humans , Intervertebral Disc/pathology , Male , Middle Aged , Myelography , Peripheral Nervous System Diseases/diagnosis , Peripheral Nervous System Diseases/diagnostic imaging , Peripheral Nervous System Diseases/surgery , Prospective Studies , Spinal Nerve Roots/diagnostic imagingSubject(s)
Diabetes Mellitus, Experimental , Gene Transfer Techniques , Genetic Therapy , Insulin/biosynthesis , Proinsulin/genetics , Protein Precursors/genetics , Animals , Diabetes Mellitus, Experimental/genetics , Diabetes Mellitus, Experimental/metabolism , Diabetes Mellitus, Experimental/therapy , Humans , Insulin/genetics , Muscle, Skeletal/metabolism , RatsABSTRACT
Osteolytic lesions of the skull have many causes, but magnetic resonance imaging may immediately distinguish cerebrospinal fluid intradiploic lakes from other causes. A case of a 16-year-old girl with such a lesion in relation to the sagittal sinus is presented and its aetiology is discussed.