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Results for “joint quantification”

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At least 181 records · Page 10Linked to original sources

PubMed2005

Association of linear plasmid 28-1 with an arthritic phenotype of Borrelia burgdorferi.

Borrelia burgdorferi, the Lyme disease spirochete, has a genome comprised of a linear chromosome and up to 21 plasmids. Loss of plasmids is associated with decreased infectivity and pathogenicity. Sixteen transformants were generated by transforming the noninfectious clone 5A13 with the recombinant plasmid pBBE22. The transformants were classified into nine groups based on plasmid content analysis. An infectivity study revealed that all nine transformants examined, each of which represented one of the plasmid patterns, were infectious in mice with severe combined immunodeficiency (SCID) regardless of their genomic compositions. Tissue bacterial quantification revealed that the loss of plasmids significantly reduced the spirochete burden in the heart and joint tissues, not in the skin, suggesting virulence factors may be tissue specific. Four transformants containing lp28-1 induced severe arthritis in SCID mice, in contrast to the five transformants lacking lp28-1. These pathogenicity studies associated lp28-1 with an arthritic phenotype and further studies may identify factors that contribute to arthritic pathology.

Animals↗

PubMed2002

Screening for amyloid in subcutaneous fat tissue of Egyptian patients with rheumatoid arthritis: clinical and laboratory characteristics.

OBJECTIVE: To screen for amyloid and to assess associated clinical and laboratory characteristics in Egyptian patients with rheumatoid arthritis (RA). METHODS: Abdominal subcutaneous fat aspirates were consecutively collected from 112 patients (103 women, nine men) having RA for five years or more. To detect amyloid, fat smears were stained with Congo red and the concentration of amyloid A protein in fat tissue was measured. Clinical, radiological, and laboratory characteristics of the patients were assessed. RESULTS: Amyloid was detected in eight (7%) of the fat smears stained with Congo red. Compared with the Congo red stain, the sensitivity for detecting amyloid by measurement of amyloid A protein in fat tissue was 75% and the specificity was 100%. The amount of amyloid found was small for both methods. The median disease duration of the eight amyloid patients was significantly longer (17 years) than that of the non-amyloid patients (10 years). Bronchopulmonary disease and constipation were more common, whereas proteinuria and chronic renal insufficiency were not. The number of swollen joints and the number of red blood cells were significantly lower in the amyloid group. CONCLUSIONS: Quantification of amyloid A protein and staining with Congo red are strongly concordant methods of screening for amyloid in fat tissue. The prevalence of amyloid in Egyptian patients with RA is 7%. Proteinuria is not a discriminating feature, whereas long disease duration, constipation, bronchopulmonary symptoms, and a moderate to low number of red blood cells may help to identify the arthritic patients with amyloid.

Adipose Tissue↗

PubMed2003

Cooperation between area 17 neuron pairs enhances fine discrimination of orientation.

We examined 66 complex cells in area 17 of cats that were paralyzed and anesthetized with propofol and N2O. We studied changes in ensemble responses for small (<10 degrees ) and large (>10 degrees ) differences in orientation. Examination of temporal resolution and discharge history revealed advantages in discrimination from both dependent (e.g., synchronization) and independent (e.g., bursting) interspike interval properties. For 27 pairs of neurons, we found that the average cooperation (the advantage gained from the joint activity) was 57.6% for fine discrimination of orientation but <5% for gross discrimination. Dependency (probabilistic quantification of the interaction between the cells) was measured between 29 pairs of neurons while varying orientation. On average, the dependency tuning for orientation was 35.5% narrower than the average firing rate tuning. The changes in dependency around the peak orientation (at which the firing rate remains relatively constant) lead to substantial cooperation that can improve discrimination in this region. The narrow tuning of dependency and the cooperation provide evidence to support a population-encoding scheme that is based on biologically plausible mechanisms and that could account for hyperacuities.

Action Potentials↗

PubMed2005

Knee cartilage defect documentation: computer assistance in quantification of cartilage defects.

In order to determine the potential for a computer-assisted program to allow accurate and reproducible measurements of joint surface defects, area measurements were repeated 10 times by three observers for two complex lesions of predetermined size. The results indicate that this system offers a significant improvement over the surgeon's freehand method of assessment and that further development is indeed warranted.

Cartilage Diseases↗

PubMed2001

Mobility of the first tarsometatarsal joint in hallux valgus patients: a radiographic analysis.

Hypermobility of the first tarsometatarsal (TMT 1) joint in the sagittal plane plays a role in the etiology and treatment of the hallux valgus complex. However, objective quantification of this mobility is still a problem. We performed a radiographic analysis of TMT 1 mobility in the sagittal plane in 94 hallux valgus patients aged 15 to 65 years. We examined 94 feet with symptomatic hallux valgus deformity requiring operative correction. Excluded were patients with osteoarthritis, inflammatory diseases or previous operations on the foot. The TMT 1 mobility was tested with a clinical test and by radiographic measurement using the modified Coleman block test. The mean mobility of the TMT 1 joint in the sagittal plane in the patient group was 12.9 degrees (SD 4.80). In addition, there was a statistically significant difference between two subgroups: patients with and without clinical TMT 1 hypermobility. No correlation of TMT 1 (hyper)mobility and radiographic second ray hypertrophy was found. This simple method can produce additional information to the clinical TMT 1 hypermobility test in the sagittal plane.

Adolescent↗

PubMed2002

[Radiologic progression of rheumatoid arthritis in early basic drug therapy].

For therapy and follow-up control in early disease modifying antirheumatic drug (DMARD) treated rheumatoid arthritis (RA), objective quantification is still lacking. Therefore, radiological analyses are considered the most appropriate method. One aim of this study was to retrospectively determine the time-dependent progression of joint damage in RA patients on DMARDs. Outpatient records and radiographs from hands and feet of 54 RA patients on DMARDs were evaluated. Radiographs were quantified by using the original Larsen score and a newly developed computer-assisted quantification software. Our observations showed that radiologically-detectable damage in all patients, regardless of their treatment, is most pronounced during the first year of disease, being mitigated and generally progressing linearly in the subsequent years. Cumulative ESR correlated with RA progression, and its reduction with therapeutic efficacy.

Antirheumatic Agents↗

PubMedDate not supplied

Inflammatory cell infiltrate and RANKL/OPG expression in rheumatoid synovium: comparison with other inflammatory arthropathies and correlation with outcome.

OBJECTIVES: To evaluate if the immunofluorescence analysis of synovial tissue (ST) using antibodies against RANKL/OPG, conjugated with the immunophenotyping of lymphocytes and macrophages, could be of diagnostic and prognostic value in rheumatoid arthritis (RA) patients. METHODS: 3-year prospective study of 103 consecutive patients submitted to closed needle biopsy for diagnostic purposes. ST was analyzed with routine histologic techniques and immunofluorescence, using monoclonal antibodies against RANKL, OPG, CD163, CD68, CD4, CD8, interferon-gamma and CD19. Patients were prospectively evaluated with a clinical, laboratorial and radiological protocol. At the end of the follow-up patients were divided according to the final diagnosis. Results of the initial histologic evaluation were compared between the main diagnostic groups and in RA patients histologic data was correlated with clinical and radiologic outcome measures. RESULTS: The RANKL/OPG ratio and the inflammatory infiltrate were significatively higher in RA (n = 25) as compared to the same ratio observed in other inflammatory joint diseases (OIJD, n = 48) and in osteoarthritis (n = 17). The difference between RA and OIJD was specifically confirmed when the comparison involved spondyloarthropathy (n = 26). Final HAQ score and radiologic outcome were correlated with the density of intimal CD68+ macrophages. Radiologic progression was correlated with subintimal CD4+ lymphocytes and CD68+ macrophages and intimal CD68 and CD163+ macrophages. CONCLUSION: The quantification of the RANKL/OPG ratio and of the number of lymphocytes in the ST might be useful to differentiate RA from other inflammatory joint diseases. The ST number of CD4+ lymphocytes and macrophages are probable predictors of radiologic progression in RA patients.

Aged↗

PubMed1999

Definition, quantification, and correction of translation deformities using long leg, frontal plane radiography.

The surgical realignment of mechanical axis deviation is necessary to prevent early joint degeneration. Modern types of external fixation systems allow alignment of the mechanical axis to exact degrees. Predominately, these are corrections of angulation deformities. In some cases, the analysis of the mechanical axis deviation does not show any angulation deformity, but rather a parallel staggering of the mechanical axis lines of a bone. Such parallel staggering of the mechanical axis lines is defined as a translation deformity of the bone. In combined deformities with angulation and translation, the center of deformity can be established proximal or distal to the limit of the bone. In translation deformities, the realignment of the mechanical axis requires a parallel restaggering made by a translation-osteotomy or by a counterangulated double osteotomy. In complex deformities with angulation and translation, the translation requires separate corrective planning. In frontal plane radiographs of the standing leg, the components of angulation and translation can be established graphically or by simple trigonometric formulas. The analysis and surgical procedure to realign translation deformities or a combination of translation and angulation deformities using an unilateral fixator device are discussed.

Adult↗

PubMed2000

Potential pediatric applications for US contrast agents: lessons from the laboratory.

OBJECTIVES: The goals of this review are to familiarize the reader with the physical basis for microbubble contrast effect and to summarize experimental studies exploring their potential pediatric applications. MATERIALS: Animal studies conducted over a 4-year period using an experimental US contrast agent for imaging the central nervous system, kidney, testes, hip joints, and malignant tumors are reviewed with respect to imaging efficacy of the agent, possible use for quantification of tissue blood flow, and potential non-vascular imaging applications. CONCLUSIONS: US contrast agents hold important potential for many clinical applications in imaging the pediatric patient.

Animals↗

PubMedDate not supplied

Spreading of epileptic afterdischarges between entorhinal cortex and hippocampus in acute experiments and the kindling model of epilepsy in the rat--comparing different methods of analysis.

Spreading of epileptiform activity in the central nervous system is one of the fundamental problems in epileptology. The patterns of spreading of after-discharges in the hippocampus and entorphinal cortex were studied in acute experiments and using the kindling model of epileptogenesis. Three methods were used to determine the time relations between EEG signals from different brain areas; visual inspections, average amount of mutual information (AAMI) and phase spectrum method. The analysis methods used are adequate for quantification of the degree of coupling between different EEG signals during an afterdischarge, but should be used jointly since different signal features are taken into consideration by different methods. During an afterdischarge only at the beginning the focal area is clearly leading the other brain areas; thereafter the pattern becomes more complex.

Animals↗

PubMed1999

Noninvasive technique for measuring in vivo three-dimensional carpal bone kinematics.

Our present knowledge of the three-dimensional kinematic behavior of skeletal joints has been largely acquired with cadaveric models and use of invasive monitoring. In the wrist, the small size and complex motion of the carpal bones present a difficult challenge for implanted internal or external marker systems. This paper describes a technique for quantifying the three-dimensional kinematics of the wrist and carpal bones in vivo using noninvasive computed tomographic imaging. An error analysis employing a cadaveric specimen suggests that noninvasive carpal kinematics can be measured with an accuracy within 2 degrees of rotation and 1 mm of translation along a helical axis of motion. The in vivo application of this technique is illustrated with a single normal individual. Potential applications include the quantification of normal wrist motion, analysis of pathomechanics, and evaluation of surgical intervention. The technique is also applicable to other joints and imaging modalities.

Anatomy, Cross-Sectional↗

PubMed1998

Collagenase 1 and collagenase 3 expression in a guinea pig model of osteoarthritis.

OBJECTIVE: To analyze the in vivo compartmental expression of collagenases 1 and 3 (MMP-1 and MMP-13) in the Hartley guinea pig model of spontaneously occurring osteoarthritis (OA) for the purpose of elucidating their roles in the pathogenesis of OA. METHODS: Competitive reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry quantification of messenger RNA (mRNA) and protein levels in medial and lateral tibial cartilage obtained from the knee joints of 2-month-old (no OA) and 12-month-old (OA) guinea pigs. RESULTS: The patterns of mRNA expression of collagenases 1 and 3 varied with the age of the animal and the compartment of the knee. We also found focal areas of collagenase 1 and collagenase 3 proteins localized to the extracellular matrix of OA lesion sites, coincident with three-quarter/one-quarter collagen cleavage. Collagenase 3 protein was also abundant throughout the medial tibial cartilage of 2-month-old animals. CONCLUSION: This represents the first description of bona fide collagenase 1 in a rodent species. Recent evidence, however, based on analysis of mitochondrial DNA homologies, suggests that the guinea pig is not a member of the order Rodentia and may be more closely allied with lagomorphs. This taxonomic controversy leaves open to question the issue of the expression of collagenase 1 in other rodents, such as mice and rats. The presence of active collagenases 1 and 3 at OA lesion sites is consistent with an important role of these enzymes in the cartilage degradation of OA in guinea pigs. The expression of collagenase 3 in medial tibial cartilage from 2-month-old guinea pigs may signify a role of this enzyme in cartilage remodeling with growth and development, or it may represent an early molecular manifestation of OA.

Animals↗

PubMed2005

Increased cytokine secretion in patients with failed implants compared with patients with primary implants.

All total joint replacements generate wear debris; yet, some implant prostheses fail while others survive despite the presence of ultrahigh molecular weight polyethylene particulate. It was hypothesized that patients with failed hip implants who have osteolysis will secrete higher inflammatory cytokines than patients receiving total joint replacements. Our study evaluated the peripheral blood monocyte response to varying polyethylene particle volume ratios through cytokine quantification in two patient populations: patients having revision surgery for failed total hip replacements (failed implant group) and patients having primary total hip surgery for osteoarthritis of the hip (primary implant group). We observed elevation of all three proinflammatory cytokines tested (interleukin-6, interleukin-1, and tumor necrosis factor-alpha) in response to polyethylene particulate challenge when compared with the controls in both patient groups. The population with failed implants also had a higher absolute cytokine response to polyethylene exposure compared with the control patients having primary implants. These findings suggest that patients with failed implants have a greater inflammatory cytokine response to polyethylene than seen in patients with primary implants.

Arthroplasty, Replacement, Hip↗

PubMed2005

Theoretical accuracy of model-based shape matching for measuring natural knee kinematics with single-plane fluoroscopy.

Quantification of knee motion under dynamic, in vivo loaded conditions is necessary to understand how knee kinematics influence joint injury, disease, and rehabilitation. Though recent studies have measured three-dimensional knee kinematics by matching geometric bone models to single-plane fluoroscopic images, factors limiting the accuracy of this approach have not been thoroughly investigated. This study used a three-step computational approach to evaluate theoretical accuracy limitations due to the shape matching process alone. First, cortical bone models of the femur tibia/fibula, and patella were created from CT data. Next, synthetic (i.e., computer generated) fluoroscopic images were created by ray tracing the bone models in known poses. Finally, an automated matching algorithm utilizing edge detection methods was developed to align flat-shaded bone models to the synthetic images. Accuracy of the recovered pose parameters was assessed in terms of measurement bias and precision. Under these ideal conditions where other sources of error were eliminated, tibiofemoral poses were within 2 mm for sagittal plane translations and 1.5 deg for all rotations while patellofemoral poses were within 2 mm and 3 deg. However, statistically significant bias was found in most relative pose parameters. Bias disappeared and precision improved by a factor of two when the synthetic images were regenerated using flat shading (i.e., sharp bone edges) instead of ray tracing (i.e., attenuated bone edges). Analysis of absolute pose parameter errors revealed that the automated matching algorithm systematically pushed the flat-shaded bone models too far into the image plane to match the attenuated edges of the synthetic ray-traced images. These results suggest that biased edge detection is the primary factor limiting the theoretical accuracy of this single-plane shape matching procedure.

Algorithms↗

PubMed1993

Precision of joint space width measurement in knee osteoarthritis from digital image analysis of high definition macroradiographs.

The precision of joint space width (JSW) measurements from plain film radiographs of the knee is limited by poor radio-anatomical positioning of the joint and/or insensitive methods of measurement. These limitations were overcome by establishing a precise radio-anatomical position for standing loaded and weight-bearing tunnel views of the knee, using the advantages of high definition macroradiography and a new computerized method for automatic JSW measurement from digitized macroradiographs of the knee. Reproducibility of JSW measurements was obtained from macroradiographs of knees of five post-mortem subjects and 12 patients with osteoarthritis (OA). JSW measurements were altered more by vertical than by horizontal misalignment of the X-ray beam relative to the joint space. In OA knees with medial compartment involvement, JSW measurements were more reproducible in the medial than lateral compartments in both radiographic views. In the medial compartment, the coefficient of variation for joint repositioning was 1% for minimum and 2% for average JSW, and for inter- and intraobserver errors, it was < 1% for both JSW measurements. The precision of this method will permit quantification of changes in JSW associated with disease progression and the treatment of OA.

Aged↗

PubMedDate not supplied

A sensitive assay for the measurement of serum chondroitin sulfate 3B3(-) epitope levels in human rheumatic diseases.

OBJECTIVE: To develop a sensitive assay to quantitate serum 3B3(-) levels in patients with rheumatoid arthritis (RA) and osteoarthritis (OA) as well as levels in control sera. METHODS: An enzyme-linked immunosorbent assay (ELISA) was developed using the monoclonal antibody (MAb) 3B3 to detect a chondroitin sulfate (CS) epitope in the sera and synovial fluid (SF) of RA and OA patients. Keratan sulfate levels were measured in the same biological fluids using the 5D4 monoclonal antibody. RESULTS: The detection limit for our 3B3(-) assay was 2 micrograms/L. Most OA sera sample curves run on the 3B3 assay were parallel (87.5%) to the standard curve and detectable (90.0%). RA sera sample curves were 87.1% detectable and 85.2% parallel. The 3B3(-) epitope was detectable in 60% of control sera and of these 66.7% of sample curves were parallel to the standard curve. All RA and OA SF had detectable quantities of 3B3(-). For the 3B3 assay, the OA and RA sera levels were significantly higher than for control sera (P = 0.03, P = 0.04 respectively). We found a significant correlation in a subset of paired OA sera and SF 3B3(-) concentrations. No correlation was found between age, joint activity scores, HAQ and CRP in RA patients and sera 3B3(-) and 5D4 levels. CONCLUSION: We have validated this assay for the quantification of 3B3(-) epitope in RA and OA serum. Levels of this epitope are significantly higher in sera from RA and OA patients than controls. 3B3(-) levels in RA sera were found to correlate with disease duration.

Adult↗

PubMed1983

A postsurgical evaluation of hemi-implant procedures at the first metatarsophalangeal joint: review and comparison of eighteen cases.

This presentation summarizes the results discovered on implantation surgery of 18 digits on 16 patients for correction of hallux limitus, or hallux rigidus. Of those studied, 66.7% received excellent and good results, 22.2% had fair results, and 11.1% had poor results. Comparison with the literature shows good correlation between studies and allows for quantification of the probability of positive returns on this form of surgery.

Adult↗

PubMed2004

In vivo cervical facet capsule distraction: mechanical implications for whiplash and neck pain.

While extensive research points to mechanical injury of the cervical facet joint as a mechanism of whiplash injury, findings remain speculative regarding its potential for causing pain. The purpose of this study was to examine the relationship between facet joint distraction, capsular ligament strain, cellular nociceptive responses, and pain. A novel rat model of in vivo facet joint injury was used to impose C6/C7 joint distraction in separate studies of subcatastrophic and physiologic vertebral distraction, as well as sham procedures. A common clinical measure of behavioral hypersensitivity (allodynia) was measured for 14 days after injury, as quantification of resulting pain symptoms. Also, on day 14, spinal activation of microglia and astrocytes was quantified to examine the potential role of glial activation as a physiologic mechanism of facet-mediated painful injury. Vertebral distractions of 0.90+/-0.53 mm across the rat facet joint reliably produced symptoms of persistent pain. Allodynia results showed immediate and sustained behavioral sensitivity following subcatastrophic vertebral distractions; pain symptoms were significantly greater (p<0.008) than those for other injury groups. Further, spinal astrocytic activation was also greater (p=0.049) for subcatastrophic injuries compared to lower distraction magnitudes. The mean maximum principal strain in the capsular ligament for joint distractions of 0.57+/-0.11 mm was 27.7+/-11.9%. Findings suggest that facet capsule strains comparable to those previously reported for whiplash kinematics and subcatastrophic failures of this ligament have the potential to produce pain symptoms and alter one element of nociception. Results further suggest that a mechanical threshold likely exists for painful joint distraction, providing behavioral and physiologic evidence of the cervical facet joint's mechanical injury as a source of neck pain.

Journal Article↗