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Biomedical subjects

J A Hannafin

Publications and source records attributed to J A Hannafin.

At least 19 recordsLinked to original sources
PubMed2001

Stress fracture sites related to underlying bone health in athletic females.

OBJECTIVE: The study tested the hypothesis that females who sustain stress fractures of cancellous bone have decreased bone density. DESIGN: A retrospective, controlled, cross-sectional study. SETTING: The setting of the study was a tertiary care center for Women's Sports Medicine. PATIENTS: 20 female patients under the age of 40 who had suffered a stress fracture and who had a positive diagnostic study (radiograph, bone scan, or magnetic resonance imaging) were included in the study. INTERVENTIONS: Patients who had a positive diagnostic study (radiograph, bone scan, or magnetic resonance imaging) for the diagnosis of stress fracture also underwent dual energy X-ray absorptiometry (DEXA) scans. MAIN OUTCOME MEASURE: Bone density measured by the DEXA scan, as defined by the World Health Organization criteria for osteopenia (greater than one standard deviation from the standard age-matched control). RESULTS: 8 of 9 patients with cancellous stress fractures had DEXA scans indicating osteopenia while only 3 of 11 patients with stress fractures of cortical bone had a scan indicating osteopenia (p = 0.01). CONCLUSIONS: A cancellous stress fracture in a female may be a warning sign of early onset osteopenia. We recommend that young females who have documented stress fractures of cancellous bone or cortical bone (with risk factors for osteopenia) undergo bone density evaluation.

Absorptiometry, Photon↗
PubMed2000

Insulin-like growth factor-I is expressed by avian flexor tendon cells.

Cells in normal tendon are in a resting G0 state, performing maintenance functions. However, traumatic injury introduces growth factors such as platelet-derived growth factor and insulin-like growth factor from blood as well as activates endogenous growth factors. These factors stimulate migration and proliferation of tendon cells at the wound area. Tendon cells require growth-promoting factors to transit the cell cycle. To evaluate the contribution of endogenous growth factors in tendon, extracts of the epitenon and internal compartment of avian flexor tendon as well as medium of cultured cells from the epitenon (tendon surface cells) and internal tendon (tendon internal fibroblasts) were collected to assess their ability to stimulate DNA synthesis. Acid-ethanol extracts of tissues and medium were chromatographed on a P-30 molecular sieve column and assayed for mitogenic activity by quantitating [3H]thymidine incorporation into tendon cell DNA. The extract from the internal tendon compartment was more stimulatory for DNA synthesis than that from the epitenon, particularly when tested on tendon internal fibroblasts. However, conditioned medium fractions from surface epitenon cells stimulated DNA synthesis to a high degree on both tendon surface cells and tendon internal fibroblasts. Conditioned medium from tendon internal fibroblasts was also stimulatory. An anti-insulin-like growth factor-I antibody ablated most of the mitogenic activity present in both tissues and conditioned medium. The levels of acid-extractable insulin-like growth factor-I in tendon were determined by competitive radioimmunoassay as 1.48+/-0.05 ng/g tissue for the epitenon and 3.83+/-0.03 ng/g tissue for the internal compartment. Results of Western immunoblots of conditioned medium revealed insulin-like growth factor-I at the 7.5 kDa position. Cultured tendon surface cells and tendon internal fibroblasts as well as cells in intact flexor tendon expressed insulin-like growth factor-I mRNA detected by reverse transcriptase-polymerase chain reaction. In situ hybridization histochemistry positively identified insulin-like growth factor-I mRNA in tendons from 52-day-old chickens. Platelet-derived growth factor was not detected at the protein or message levels. Furthermore, tendon surface cells and tendon internal fibroblasts both expressed receptors for insulin-like growth factor-I detected by flow cytometry. These data suggest that tendon cells express insulin-like growth factor-I mRNA and synthesize insulin-like growth factor-I in both the epitenon and the internal compartment of tendon, which is present in an inactive form, most likely bound to insulin-like growth factor-binding proteins.

Animals↗
PubMed2000

Multidirectional instability of the shoulder in the female athlete.

Multidirectional instability (MDI) of the shoulder is a complex entity, characterized by symptomatic global laxity of the glenohumeral joint. Because symptoms vary widely, making the diagnosis of MDI is not always straightforward. In addition, relatively few series of patients with this disorder have been reported. Thus, precise definition, causes, and treatment remain elusive. This article reviews the current literature regarding anatomy, biomechanics, clinical diagnosis, and treatment of MDI that are relevant to care of the female athlete.

Biomechanical Phenomena↗
PubMed2000

Adhesive capsulitis. A treatment approach.

Adhesive capsulitis of the shoulder is a condition of unknown etiology that results in the development of restriction of active and passive glenohumeral motion. The authors will review what currently is known about the etiology of idiopathic adhesive capsulitis, will raise unanswered questions regarding etiology and treatment, and will define a stage-based evaluation and treatment program. Treatment options including benign neglect, home-based and supervised physical therapy, intraarticular corticosteroid injections, closed manipulations, and arthroscopic capsular release will be reviewed critically and the authors' approach to the treatment of patients with idiopathic adhesive capsulitis also will be presented. Additionally, areas of future research will be defined.

Bursitis↗
PubMed1999

Characterization of chemotactic migration and growth kinetics of canine knee ligament fibroblasts.

Migration and proliferation of ligament fibroblasts are essential for the healing of ligament injuries. This study was designed to evaluate the migration of intraarticular (anterior and posterior cruciate) and extraarticular (medial and lateral collateral) ligament fibroblasts in response to cytokines and to determine the effect of cell passage on cell proliferation. Recombinant human platelet-derived growth factor, hepatocyte growth factor/scatter factor, and bone morphogenic protein-2 stimulated the migration of all ligament cells in a dose-dependent manner, with optimal migration at 10 ng/ml. Recombinant human epithelial growth factor preferentially stimulated the migration of intraarticular ligament fibroblasts, whereas recombinant human interleukin-1 was more effective with extraarticular ligament fibroblasts. Recombinant human insulin-like growth factor-1, insulin-like growth factor-2, transforming growth factor-beta, and fibroblast growth factor had no significant effect on the migration of ligament-derived fibroblasts. These data suggest that specific cytokines stimulate the migration of knee ligament fibroblasts and provide a rationale for possible therapeutic approaches to optimize ligament healing. Fibroblasts derived from the anterior cruciate ligament have been shown to proliferate at a slower rate than those derived from the medial collateral ligament. We have extended these observations and have demonstrated that fibroblasts from both the posterior and anterior cruciate ligaments proliferate at a slower rate than lateral and medial collateral ligament-derived fibroblasts. The differences between the growth rates of intraarticular and extraarticular fibroblasts become insignificant with serial passaging of the cells.

Animals↗
PubMed1999

Differential expression of integrin subunits in canine knee ligament fibroblasts.

A method for measuring the expression of integrin subunits on the cell surface of knee ligament fibroblasts was developed with use of flow cytometry and immunofluorescence. The ligament cells exhibited uniform size and density, as shown by forward and side-scatter properties, and showed minimal nonspecific binding of isotype control antibodies compared with unstained cells. All cells expressed the alpha5 integrin subunit; lateral collateral ligament cells stained with antibody to alpha5 showed a mean fluorescence intensity 2-fold higher than that of medial collateral ligament cells, 1.5-fold higher than that of posterior cruciate ligament cells, and 3-fold higher than that of anterior cruciate ligament cells, indicating a greater expression of the alpha5 subunit by lateral collateral ligament cells than by medial collateral, posterior cruciate, and anterior cruciate ligament cells. All cells expressed the beta1 integrin subunit; the expression by posterior cruciate ligament cells was 3-fold higher than that by medial collateral ligament or lateral collateral ligament cells and 5-fold higher than that by anterior cruciate ligament cells. All cells expressed the beta3 integrin subunit; the expression by posterior cruciate ligament cells was 1.5, 3, and 4.5-fold greater than that by lateral collateral, anterior cruciate, and medial collateral ligament cells, respectively. Our data suggest there is a differential expression of integrin subunits in knee ligament fibroblasts, and this in part may explain differences in their attachment and adherence to extracellular matrix molecules.

Animals↗
PubMed1998

Effects of exercise on Achilles tendon healing in a rat model.

The effects of motion, or lack of it, on Achilles tendon healing are not well defined. We have recently shown that immobilization has a detrimental effect on tendon healing in a rat model. The aim of this experiment was to determine whether enforced exercise had an additional beneficial effect on the mechanical and functional recovery of divided Achilles tendons in rats. Male Sprague-Dawley rats were randomly allocated into a nonexercise and an exercise group (N = 10 for each group). In both groups the right Achilles tendon was surgically transected. The left, uninjured lower limb served as an internal control. Both groups of animals were housed under identical conditions with the exception that the exercise group swam for 15 minutes per day. Functional performance was determined from the measurement of hindpaw prints of walking rats preoperatively and on alternate postoperative days. On day 15, the animals were killed and weighed, and biomechanical evaluations were performed on both the injured and uninjured Achilles tendon constructs. There were no differences in weight at time of death. All animals had an initial functional deficit that returned to near-normal by day 15. There were significant differences in the morphological and the mechanical properties of the healing Achilles tendon constructs at day 15 when comparing the injured with the uninjured Achilles tendon constructs. Supplemental exercise, however, had no effect on the functional or mechanical recovery of injured or uninjured Achilles tendons in the rat model.

Achilles Tendon↗
PubMed1998

Magnetic resonance imaging of articular cartilage in the knee. An evaluation with use of fast-spin-echo imaging.

The purpose of this study was to demonstrate that specialized magnetic resonance imaging provides an accurate assessment of lesions of the articular cartilage of the knee. Arthroscopy was used as the comparative standard. Eighty-eight patients who had an average age of thirty-eight years were evaluated with magnetic resonance imaging and subsequent arthroscopy because of a suspected meniscal or ligamentous injury. The magnetic resonance imaging was performed with a specialized sequence in the sagittal, coronal, and axial planes. Seven articular surfaces (the patellar facets, the trochlea, the femoral condyles, and the tibial plateaus) were graded prospectively on the magnetic resonance images by two independent readers with use of the 5-point classification system of Outerbridge, which was also used at arthroscopy. Six hundred and sixteen articular surfaces were assessed, and 248 lesions were identified at arthroscopy. Eighty-two surfaces had chondral softening; seventy-five, mild ulceration; fifty-three, deep ulceration, fibrillation, or a flap without exposure of subchondral bone; and thirty-eight, full-thickness wear. To simplify the statistical analysis, grades 0 and 1 were regarded as disease-negative status and grades 2, 3, and 4 were regarded as disease-positive status. When the grades that had been assigned by reader 1 were used for the analysis, magnetic resonance imaging had a sensitivity of 87 per cent (144 of 166), a specificity of 94 per cent (424 of 450), an accuracy of 92 per cent (568 of 616), a positive predictive value of 85 per cent (144 of 170), and a negative predictive value of 95 per cent (424 of 446) for the detection of a chondral lesion. Interobserver variability was minimum, as indicated by a weighted kappa statistic of 0.93 (almost perfect agreement). With use of this readily available modified magnetic resonance imaging sequence, it is possible to assess all articular surfaces of the knee accurately and thereby identify lesions that are amenable to arthroscopic treatment.

Adult↗
PubMed1997

Immunolocalization of cytokines and their receptors in adhesive capsulitis of the shoulder.

The purpose of this study was to test the hypothesis that specific cytokines are involved in the initiation and evolution of the fibrotic process in adhesive capsulitis of the shoulder. After approval from the Institutional Review Board, biopsies of shoulder capsule and synovium were collected during shoulder arthroscopy from 19 patients with adhesive capsulitis, 14 patients with nonspecific synovitis and no fibrosis or clinical evidence of adhesive capsulitis, and seven patients undergoing surgery for another pathology who had a normal capsule and synovium. Immunohistochemical localization with monoclonal antibodies to transforming growth factor-beta and its receptor, platelet-derived growth factor and its receptor, basic fibroblast growth factor, interleukin-1 beta, tumor necrosis factor-alpha, and hepatocyte growth factor was performed using standard immunoperoxidase techniques. The frequency of cytokine staining was correlated with the clinical diagnosis. Synovial cells, fibroblasts, T-cells, and B-cells were identified with specific antibodies, and newly synthesized matrix was examined for type-I and type-III collagen by immunohistochemical staining. The predominant cell types present were synovial cells and fibroblasts. Staining for type-III collagen in adhesive capsulitis tissues indicated new deposition of collagen in the capsule. There was staining for transforming growth factor-beta and its receptor, platelet-derived growth factor and its receptor, interleukin-1 beta, and tumor necrosis factor-alpha in adhesive capsulitis and nonspecific synovitis tissues, compared with minimal staining in normal capsule. Staining was more frequent in synovial cells than in capsular cells. The frequency of cell and matrix staining for transforming growth factor-beta, platelet-derived growth factor, and hepatocyte growth factor was greater in adhesive capsulitis tissues than in those from patients with nonspecific synovitis. No difference in the frequency of staining between primary (idiopathic) and secondary adhesive capsulitis was found. The results of this study indicate that adhesive capsulitis involves both synovial hyperplasia and capsular fibrosis. Cytokines such as transforming growth factor-beta and platelet-derived growth factor may be involved in the inflammatory and fibrotic processes in adhesive capsulitis. Matrix-bound transforming growth factor-beta may act as a persistent stimulus, resulting in capsular fibrosis. Understanding the basic pathophysiology of adhesive capsulitis is an important step in the development of clinically useful antifibrotic agents that may serve as novel treatments for patients with this conditions.

Adult↗
PubMed1997

Modulation of tendon healing by nitric oxide.

Nitric oxide (NO) is a small, diffusible free radical that is generated from L-arginine by a family of enzymes, collectively termed the nitric oxide synthases. We investigated the role of NO in tendon healing. NO synthase activity and immunoreactivity was absent in un-injured rat Achilles tendon. After surgical division there was a five-fold increase in NO synthase activity and immunoreactivity within the healing tendon at day 7, with a return to near baseline levels at day 14. Inhibition of NO synthase activity with oral administration of N omega-nitro-L-arginine methyl ester (L-NAME) resulted in a significant reduction in cross-sectional area (30% at day 7, p < 0.01, 50% at day 15, p < 0.001) and failure load (24% at day 7, p < 0.01) of the healing Achilles tendon constructs. Rats fed the same regimen of the enantiomer of L-NAME, (D-NAME) had normal tendon healing. These results indicate that nitric oxide synthase is induced during tendon healing and inhibition of nitric oxide synthase inhibits this tendon healing.

Achilles Tendon↗
PubMed1997

Intracellular calcium response of ACL and MCL ligament fibroblasts to fluid-induced shear stress.

This study examines the real-time intracellular calcium concentration, [Ca2+]i, response of canine medial collateral ligament (MCL) and anterior cruciate ligament (ACL) fibroblasts subjected to a fluid-induced shear stress of 25 dynes/cm2. In experiments using a modified Hanks' Balanced Salt Solution (HBSS) perfusate, both cell types demonstrated a significant increase in peak [Ca2+]i compared to respective no-flow controls, the response of MCL fibroblasts being nearly 2-fold greater than that of ACL fibroblasts. In studies where the cells were bathed in a medium of HBSS supplemented with 2% newborn bovine serum (NBS) and then introduced to flow with the same medium, ACL fibroblasts responded nearly 3-fold greater than MCL fibroblasts. Neomycin (10 mM), thapsigarigin (1 microM) and Ca(2+)-free media supplemented with EGTA (1 mM) were able to inhibit significantly the [Ca2+]i response to flow with HBSS in both fibroblasts. Thapsigargin also blocked the NBS flow response in both cell types, while neomycin and Ca(2+)-free media significantly inhibited the ACL response. Our findings demonstrate that ACL and MCL cells are not the same. These differences may be related to the disparate healing capacity of the ACL and MCL observed clinically.

Animals↗
PubMed1996

Nitric oxide: an important articular free radical.

Nitric oxide is a small molecule that is synthesized by a family of enzymes, the nitric oxide synthases, and is overproduced in rheumatoid arthritis and osteoarthrosis. The aim of this investigation was to elucidate the potential sources of nitric oxide in joint tissues and to determine if the production of nitric oxide could be inhibited by dexamethasone or methotrexate, two agents that inhibit other forms of inducible nitric oxide synthase. Methotrexate inhibits the synthesis of biopterin, which is a co-factor for nitric oxide synthase. Explants of human and bovine cartilage and cultured chondrocytes released large amounts of nitrite, the stable end product of nitric oxide, when stimulated with endotoxin, interleukin-1 beta, or tumor necrosis factor-alpha. The production of nitrite was time-dependent and endotoxin, interleukin-1 beta, and tumor necrosis factor-alpha dose-dependent and was inhibited by the nitric-oxide-synthase inhibitors N omega-nitro-L-arginine methyl ester and aminoguanidine. The inducible nitric oxide synthase in bovine chondrocytes was calcium-dependent and was inhibited by high concentrations of methotrexate or dexamethasone. No constitutive nitric-oxide-synthase activity and little or no inducible nitric-oxide-synthase activity were demonstrable in explants or cell cultures derived from menisci. Fresh explants of bovine articular synovial tissue constitutively released nitrite that was inhibited by N omega-nitro-L-arginine methyl ester, but the release could not be enhanced by endotoxin, interleukin-1 beta, or tumor necrosis factor-alpha. There was no constitutive or inducible production of nitrite by explants or cells derived from the synovial tissue or shoulder capsule of a human or by explants or cells derived from canine anterior cruciate, posterior cruciate, medial collateral, lateral collateral, or patellar ligaments. Taken together, these results indicate that chondrocytes represent the major source of inducible nitric oxide synthase and nitric oxide during inflammation or infection of a joint.

Animals↗
PubMed1995

Effect of stress deprivation and cyclic tensile loading on the material and morphologic properties of canine flexor digitorum profundus tendon: an in vitro study.

The effect of stress deprivation and cyclic tensile loading on the mechanical and histologic properties of the canine flexor digitorum profundus tendon was examined using an in vitro system. Stress deprivation resulted in a progressive and statistically significant decrease in the tensile modulus over an 8-week period. Histologically, stress-deprived tendons demonstrated quantitative changes in the morphology and number of cells and in the alignment of collagen. The change in tensile properties was not associated with an alteration in the water content of the tissue, but the change appeared to be dependent on the presence of a viable cell population. Dead (acellular) tendons did not undergo any alteration in tensile modulus in this in vitro system. In vitro cyclic tensile loading of tendons over a 4-week time period resulted in a significant increase in the tensile modulus (93% of the control) compared with that of the stress-deprived tendons (68% of the control). This loading regimen also maintained the normal histologic pattern of the tendons. The results of this study are similar to those previously reported for in vivo studies and suggest that this in vitro model may represent a valid system with which to test the effects of various stress conditions on the tensile properties of tissues.

Analysis of Variance↗
PubMed1995

Isolated rupture and repair of the popliteus tendon.

The authors report the case of a 21-year-old woman who sustained a femoral avulsion of the popliteus tendon in a motor vehicle accident. The posterolateral injury was suspected on physical examination and confirmed by magnetic resonance imaging and arthroscopic examination. The popliteus tendon was repaired using two suture anchors. Mild clinical instability was present initially and resolved postoperatively. No residual pain, weakness, or posterolateral instability was noted.

Accidents, Traffic↗
PubMed1995

Lateral epicondylitis: correlation of MR imaging, surgical, and histopathologic findings.

PURPOSE: To determine the value of magnetic resonance (MR) imaging in the clinical management of chronic refractory lateral epicondylitis. MATERIALS AND METHODS: Coronal three-dimensional Fourier transform, multiplanar gradient-recalled-echo, and fat-suppressed sagittal images were obtained in 33 patients. Twenty of these patients underwent surgical débridement and/or primary tendon repair and were included in the correlative study. Surgical and pathologic reports were reviewed to determine the location and gross characteristics of the tissue. RESULTS: Findings at MR imaging correlated with the surgical findings of primary degeneration of the extensor carpi radialis brevis (n = 20). Histopathologic examination demonstrated neovascularization, disruption of collagen, and mucoid degeneration without inflammation. CONCLUSION: The use of MR imaging in patients with recalcitrant lateral epicondylitis assists in surgical planning. The definition of tendon degeneration and degree of tear, as depicted on MR images, correlate well with surgical and histologic findings.

Adult↗
PubMed1994

Effect of cyclic and static tensile loading on water content and solute diffusion in canine flexor tendons: an in vitro study.

This study was designed to determine the effects of various loading conditions (no load and static and cyclic tensile load) on the water content and pattern of nutrient diffusion of canine flexor tendons in vitro. Region D (designated by Okuda et al.) of the flexor digitorum profundus was subjected to a cyclic or static tensile load of 100 g for times ranging from 5 minutes to 24 hours. The results demonstrated a statistically significant loss of water in tendons subjected to both types of load as compared with the controls (no load). This loss appeared to progress with time. However, neither static nor cyclic loading appeared to alter the diffusion of 3H-glucose into the tendon over a 24-hour period compared with the controls. These results suggest that any benefit in tendon repair derived from intermittent passive motion is probably not a result of an increase in the diffusion of small nutrients in response to intermittent tensile load.

Animals↗
PubMed1994

Magnetic resonance signals in healing menisci: an experimental study in dogs.

This study examined the magnetic resonance imaging (MRI) signal from healing menisci in adult dogs. Complete, full-thickness radial tears were created in the medial menisci of adult dogs and allowed to heal spontaneously. Menisci were harvested and examined at 8, 12, and 26 weeks after injury using a spin-echo imaging sequence. After imaging, the menisci were processed for routine histologic examination. The results of the study demonstrated that the repair tissue consistently yielded an increased MRI signal as compared with the normal meniscal tissue. This increased signal persisted at 26 weeks even though the repair tissue had modulated from fibrovascular scar tissue into fibrocartilage. The results of this study confirm the clinical impression that normal fibrovascular repair tissue in the healing meniscus can emit persistently increased signals on MRI examination. However, the long-term history of these signals remains unknown.

Animals↗