Practice patterns in longitudinal lupus care provision: patient and physician perspectives

Background/purpose

To plan a quality improvement project, we need to understand the practice patterns of physicians. We undertook an online survey of systemic lupus erythematosus (SLE) patients and physicians providing care to SLE patients to determine the patterns of medical care provided to SLE patients.

Materials and methods

Two self-report surveys were developed. A 12-item survey for the patients and a 13-item survey for physicians enquired about longitudinal care for SLE. Surveys were administered online to physicians providing care to SLE patients, and to patients who self-identified as having SLE, through the Lupus Society of Illinois. Patient and physician data were analyzed for physician practice patterns for SLE care, using chi square tests and t tests. A P value of 0.05 or less was considered significant on two-tailed tests.

Results

A total of 283 patients completed the survey. Mean (SD) age and disease duration of patients were 45.9 (13.2) and 12.7 (9.7) years. Half of the participants were being seen at 3–4-month intervals. More than 70% of patients reported being tested for antinuclear antibody (ANA), and 20–30% anti-ENA antibody and Sjögren’s (SSA/SSB) antibodies, respectively, at each follow-up visit. Eighty-six rheumatologists completed the surveys. Mean (SD) age was 55 (12) years and 56% were men. More than half (54%) provided care only in a private practice setting. More than 80% of physicians reported seeing their SLE patients at 3–4-month interval. Only 2% reported performing ANA tests at each visit, while 4–5% performed anti-ENA and anti-SSA/SSB antibody tests at each visit for their SLE patients. More than 75% of physicians in private practice also ordered sedimentation rate at each visit for their SLE patients.

Conclusions

Unnecessary laboratory investigations may be being ordered routinely for patients at every visit. These results indicate a need for physician education on indications and utility of some of the laboratory tests such as ANA.

Validation of the LupusPRO version 1.8: an update to a disease-specific patient-reported outcome tool for systemic lupus erythematosus

Objectives LupusPRO has shown good measurement properties as a disease-specific patient-reported outcome tool in systemic lupus erythematosus (SLE). For the purpose of clinical trials, the version 1.7 (v1.7) domain of Pain-Vitality was separated into distinct Pain, Vitality and Sleep domains in v1.8, and the psychometric properties examined. Methods A total of 131 consecutive SLE patients were self-administered surveys assessing fatigue (FACIT, SF-36), pain (Pain Inventory, SF-36), insomnia (Insomnia Severity Index), emotional health (PHQ-9, SF-36) and quality of life (SF-36, LupusPRO) at routine care visits. Internal consistency reliability (ICR) for each domain was obtained using Cronbach's alpha. The convergent construct validity of LupusPRO domains with corresponding SF-36 domains or tools were tested using Spearman correlation. Varimax rotations were conducted to assess factor structures of the LupusPRO v1.8. Results Mean (SD) age was 40.04 (14.10) years. Scores from the LupusPRO-Sleep domain strongly correlated with insomnia scores, while LupusPRO-Vitality correlated strongly with fatigue (FACIT) and SF-36 vitality. The LupusPRO-Pain domain correlated strongly with pain (SF36 Bodily-Pain, Pain Inventory) scores. Similarly, the LupusPRO domains of Physical and Emotional Health had significant correlations with corresponding SF-36 domains. The ICR for HRQoL and non-HRQoL were 0.96 and 0.81. LupusPRO (domains HRQoL and QoL) scores correlated with disease activity. Principal component analysis included seven factor loadings presenting for the HRQOL subscales (combined Sleep, Vitality, and Pain), and three factors for the NHRQoL (Combined Coping and Social Support). Conclusions LupusPRO v1.8 (including its Sleep, Vitality, and Pain domains) has acceptable reliability and validity. Use of LupusPRO as an outcome measure in clinical trials would facilitate responsiveness assessment.

Caregiving, dyadic quality of life and dyadic relationships in lupus

Aims

Systemic lupus erythematosus (SLE) mostly affects young women, adversely affecting their quality of life (QOL). Caregivers may experience caregiver burden (CGB), and it may lower the quality of their relationship. Herein we studied caregiving and CGB and their effects on QOL and relationships in SLE.

Methods

We recruited 10 dyads from the Lupus Clinic. Data collected included demographics, CGB (CGB Scale, screen for CGB), QOL (SF-36) and the quality of the dyadic relationship (Dyadic Adjustment Scale (DAS)). We calculated correlation coefficients for associations between (i) CGB and (ii) dyadic QOL or DAS.

Results

The mean (± SD) age of SLE patients was 35.2 (± 9) years and of caregivers was 37.3 (± 9.64) years. The mean (± SD, min–max) total CGB score was 9.1 (± 5.8, 0–19). The caregiver's QOL correlated strongly with some of the domains of the patient's QOL. The SLE-related CGB was associated with the caregiver's own QOL and their SLE partner's QOL. The dyadic DAS was linked to the patient's QOL.

Conclusions

Because (i) CGB in SLE is associated with the caregiver's own QOL and with their SLE partner's QOL, and because (ii) the dyadic DAS score is linked primarily to the patient's QOL, then to optimize patient health outcomes and to decrease CGB, focus should be not only on the patient but should include the dyadic unit. Significant findings: To optimize patient outcomes of SLE patients, focus should be on the dyadic unit. CGB in SLE is associated with the caregiver's own QOL and with the SLE partner's QOL, making it crucial to study this relationship in more detail.

Lupus Impact Tracker is responsive to physician and patient assessed changes in systemic lupus erythematosus

OBJECTIVE

To evaluate the responsiveness of Lupus Impact Tracker (LIT) to changes in physician and patient disease activity assessments over time.

METHODS

Available longitudinal data from routine patient care visits on LIT, physician assessed disease activity (physician global assessment (PGA), SELENA-SLEDAI score, SELENA Flare Index (SFI)), and patient-reported changes in systemic lupus erythematosus (SLE) health status were analyzed. Significant, clinically important change (worsening or improvement) in physician disease activity assessment or patient-reported SLE health status were judged using the following criteria: change of 0.3 on PGA, 4 on SELENA-SLEDAI, change in SFI status over time, and change of 2 in either direction in patient-reported SLE health status. Mixed model regression analysis was used to compare changes in LIT using the above criteria.

RESULTS

There were 1184 observations with significant changes in physician disease activity or patient-reported measure for 182 patients' data across 1364 visits. Patients' mean (SD) age and SELENA-SLEDAI were 43.5 (13.2) years and 6.4 (7.3) respectively. LIT mean scores decreased by more than 3 with improvement in PGA (standardized response mean -0.26, p < 0.05), while it increased by more than 5 with worsening in SELENA-SLEDAI (standardized response mean 0.42, p = 0.01). Mean change in LIT of greater than ±3 was noted with change in SFI status (p < 0.05). Mean LIT score decreased by greater than 4 and increased by greater than 2 with patient-reported improvement and worsening in SLE health status respectively (p < 0.05).

CONCLUSIONS

LIT is responsive to physician-assessed and patient-assessed changes in disease status. A mean LIT change of 2-4 may represent a significant clinical change in LIT. It is an effective tool that may be used by patients and physicians in tracking disease impact in SLE patients.

The French-Canadian validation of a disease-specific, patient-reported outcome measure for lupus

OBJECTIVES

The objective of this paper is to perform the cross-cultural validation of the French version of the LupusPRO, a disease-targeted patient-reported outcome measure, among systemic lupus erythematosus (SLE) patients in Canada.

METHODS

The French version of the LupusPRO and the MOS SF-36 were administered; demographic, clinical and serological characteristics were obtained. Disease activity (SELENA-SLEDAI and the Lupus Foundation of America definition of flare) and damage (SLICC/ACR SDI) were assessed. Physician disease activity and damage assessments were ascertained using visual analog scales. Internal consistency reliability (ICR), test-retest reliability (TRT), convergent and discriminant validity (against corresponding domains of the SF-36), criterion validity (against disease activity, damage or health status) and known group validity were tested.

RESULTS

A total of 99 French-Canadian SLE patients participated (97% women, mean (SD) age 45.2 (14.5) years). The median (IQR) SELENA-SLEDAI and SDI were 3.5 (6.0) and 1.0 (2.0), respectively. The ICR of the LupusPRO domains ranged from 0.81 to 0.93 (except for lupus symptoms, procreation and coping), while TRT ranged from 0.72 to 0.95. Convergent and discriminant validity, criterion validity and known group validity against disease activity, damage and health status measures were observed. Confirmatory factor analysis showed a good fit.

CONCLUSION

The LupusPRO has fair psychometric properties among French-Canadian patients with SLE.

Serum free light chains, interferon-alpha, and interleukins in systemic lupus erythematosus

OBJECTIVE

Interleukin-6 (IL-6), interleukin-10 (IL-10), interferon-alpha (IFN-α), and free light chains (FLCs: lambda, kappa) have all been noted to be of importance in systemic lupus erythematosus (SLE). Herein, we quantified and explored the relationship between these inflammatory mediators and disease activity in SLE; and stratified by their current anti-dsDNA antibody status.

METHODS

Seventy-seven SLE patients underwent assessment of disease activity using the SLE disease activity index (SLEDAI). Serum FLC (lambda, kappa, and total), IL-6, IL-10, and IFN-α were quantified. Demographics of disease characteristics were determined by chart reviews. Statistical analyses included Mann-Whitney test, chi square, and linear regression analyses.

RESULTS

Mean (SD) age of the patients was 44.9 ± 12.7 years; SLEDAI (mean ± SD) was 3.4 ± 4.0. Serum lambda FLC levels had a moderate correlation (r = 0.46 with physician global assessment, 0.44 with SLEDAI) and the strongest correlation with disease activity as compared with other inflammatory mediators including current dsDNA antibody status. After adjusting for prednisone use, the correlation of lambda FLC with PGA (r = 0.48) and SLEDAI (r = 0.52) was better than of current dsDNA antibody status with PGA (r = 0.33) and adjusted SLEDAI (r = 0.24), respectively. IL-10 and IFN-α activity did not correlate with disease activity. Serum FLC and IL-6 levels could differentiate between active and inactive SLE patients. Serum lambda FLC and IL-6 levels differed significantly among patients with and without current dsDNA antibodies. Serum lambda FLC levels accounted for 31% of variance in SLEDAI scores.

CONCLUSION

Serum FLC and IL-6 are potentially useful biomarkers of disease activity in SLE. Further studies, with larger study sample and longitudinal design, are indicated.

The biomechanical effects of focused muscle training on medial knee loads in OA of the knee: a pilot, proof of concept study

BACKGROUND

High dynamic loads of the medial knee are associated with tibiofemoral osteoarthritis (OA) severity and progression. The lower extremity acts as an integrated kinetic unit, thus treatments targeting adjacent segments may promote reductions in the loading of a symptomatic knee. This study examined the biomechanical effects of a lower extremity exercise regimen, emphasizing training of hip abductor musculature, on dynamic knee loads in individuals with knee OA.

METHODS

Six subjects with medial compartment knee OA participated in a proof of concept study of a four-week exercise program specifically targeting the hip abductor musculature in combination with traditional quadriceps and hamstring training. Assessments included gait analyses to measure the external knee adduction moment, a surrogate marker of medial knee joint loading as well as WOMAC questionnaires and strength evaluations.

RESULTS

All subjects demonstrated a decrease in their external knee adduction moment, with an average decrease of 9% (p<0.05) following the exercise intervention. There was a 78% (p<0.05) decrease in WOMAC knee pain scores.

CONCLUSIONS

These results suggest that targeting hip, rather than only knee musculature, may represent an effective biomechanically-based treatment option for medial knee OA.

The effects of oral glucosamine on joint health: is a change in research approach needed?

OBJECTIVE

Oral glucosamine (GlcN) has been widely studied for its potential therapeutic benefits in alleviating the pain and disability of osteoarthritis (OA). Its popularity has grown despite ongoing controversy regarding its effectiveness vs placebo in clinical trials, and lack of information regarding possible mechanisms of action. Here, we review the state of knowledge concerning the biology of GlcN as it relates to OA, and discuss a framework for future research directions.

METHODS

An editorial "narrative" review of peer-reviewed publications is organized into four topics (1) Chemistry and pharmacokinetics of GlcN salts (2) Biological effects of GlcN salts in vitro (3) Therapeutic effects of GlcN salts in animal models of OA and (4) GlcN salts in the treatment of clinical OA.

RESULTS

Data reporting potent pleiotropic activities of GlcN in in vitro cell and explant cultures are discussed in the context of the established pharmacokinetic data in humans and animals. The available clinical trial data are discussed to place the patient in the context of controlled research on disease management.

CONCLUSIONS

Future research to determine therapeutic mechanisms of GlcN salt preparations will require use of standardized and clinically relevant in vitro assay systems and in vivo animal models for testing, as well as development of new outcome measures for inflammation and pain pathways in human OA.

Pain and its relationship with muscle strength and proprioception in knee OA: results of an 8-week home exercise pilot study

Muscle strength and proprioception deficits have been recognized in knee OA. Pain is the symptomatic hallmark of knee OA. Indirect evidence suggests that muscle strength and proprioception deficits may be interrelated and that pain may have a confounding influence on the measurement of these factors in knee OA. However, these relationships have never been clearly evaluated. Therefore, the purpose of this investigation was to investigate relationships between pain, muscle strength, and proprioception in subjects with knee OA before and after an 8-week home exercise program. This study evaluated thirty-eight subjects with knee OA. Subjects were taught standard quadriceps strengthening exercises that were to be performed daily at home. Pain, muscle strength, and proprioceptive function were measured at baseline and after 8 weeks of therapy. Significant improvements in pain (42%, p<0.001) and quadriceps muscle strength (30%, p<0.001) were noted. Significant indirect associations were observed between pain and both muscle strength (rho=-0.39, p=0.01) and proprioceptive acuity (rho=-0.35, p=0.03) at baseline. Changes in pain were directly associated with changes in muscle strength (rho=0.45, p=0.005) and proprioceptive acuity (rho=0.41, p=0.01) with exercise. The association of pain with both muscle strength and proprioception should prompt future studies to consider and adjust for the influence of pain on neuromuscular factors in knee OA.

The relationship between hip joint space width, center edge angle and acetabular depth

OBJECTIVE

Radiographic parameters used to define acetabular dysplasia may be related to anthropological characteristics independent of dysplasia. The goal of the present study was to investigate the relationship between the minimal joint space width (JSW) of the hip and the parameters that define acetabular dysplasia, in clinically normal subjects.

DESIGN

One hundred and eighteen patients who underwent supine abdominal radiography for non-rheumatological indications and had no hip pain or history of hip arthritis were evaluated. JSW was quantified manually using dial calipers, and center edge (CE) angle and acetabular depth were measured for each hip.

RESULTS

CE angle, but not acetabular depth, correlated (inversely) with the minimal hip JSW (r=-0.26 and -0.20, P=0.005 and 0.038, R (right) and L (left) hips, respectively). CE angle inversely correlated with the pelvic width (r=-0.27 and 0.27, P=0.003 and 0.004, R and L hips, respectively) and acetabular depth correlated with subject's height (r=0.27 and 0.42, P=0.008 and <0.001 R and L hips, respectively) and leg length (r=0.27 and 0.45, P=0.008 and <0.001, R and L hips, respectively). Also, pelvic width correlated significantly with the JSW (r=0.27 and 0.20, P=0.003 and 0.033, for R and L hips, respectively).

CONCLUSIONS

The radiographic parameters used to define acetabular dysplasia, CE angle and acetabular depth, are strongly associated with anthropological variables and CE angle is associated with minimal JSW of the hip. It is important to recognize that height and limb length variability may affect radiographic parameters of acetabular dysplasia, and thus may falsely suggest the presence of anatomic abnormalities in some patients.

Etanercept therapy in patients with a positive tuberculin skin test

INTRODUCTION

Etanercept (Enbrel), a tumor necrosis factor-alpha (TNF-alpha) antagonist, is commonly used for the treatment of a variety of rheumatic diseases. Tuberculosis (TB) infections have been associated with chronic TNF-alpha blocking therapy, and there is concern that such therapy may predispose patients to TB reactivation. In this study, we attempted to evaluate the frequency of latent TB reactivation among patients treated with etanercept.

METHODS

All patients with either a positive purified protein derivative (PPD) for TB or a previous history of therapy for latent TB infection (LTBI) who were prescribed etanercept in the division of rheumatology at John H. Stroger Jr Hospital of Cook County prior to November 2005 were enrolled in this study. A retrospective chart review was performed looking for evidence of active TB infection during etanercept treatment.

RESULTS

Forty-eight patients with a positive PPD were treated with etanercept, and followed for an aggregate of 818 patient-months of etanercept exposure, with a mean follow-up period of 17 months (range 5 to 48 months); all patients had at least one follow-up visit. Forty-four patients (92%) were fully or partially treated with LTBI therapy prior to initiation of etanercept. Chest roentgenograms were available for review in 43 patients, ten of which had evidence of old granulomatous disease. No cases of active TB were described during the study period.

CONCLUSIONS

In this small retrospective analysis, none of the 48 patients with positive PPDs who were treated with etanercept for average of 17 months developed active TB.

Bone mineral density in the proximal tibia varies as a function of static alignment and knee adduction angular momentum in individuals with medial knee osteoarthritis

Based on the premise that bone mass and bone geometry are related to load history and that subchondral bone may play a role in osteoarthritis (OA), we sought to determine if static and dynamic markers of knee joint loads explain variance in the medial-to-lateral ratio of proximal tibial bone mineral density (BMD) in subjects with mild and moderate medial knee OA. We utilized two surrogate markers of dynamic load, the peak knee adduction moment and the knee adduction angular momentum, the latter being the time integral of the frontal plane knee joint moment. BMD for medial and lateral regions of the proximal tibial plateau and one distal region in the tibial shaft was measured in 84 symptomatic subjects with Kellgren and Lawrence radiographic OA grades of 2 or 3. Utilizing gait analysis, the peak knee adduction moment (the external adduction moment of greatest magnitude) and the time integral of the frontal plane knee joint moment (the angular momentum) over the entire stance phase as well as for each of the four subdivisions of stance were calculated. The BMD ratio was not significantly different in grade 2 (1.32 +/- 0.27) and grade 3 knees (1.47 +/- 0.40) (P = 0.215). BMD of the tibial shaft was not correlated with any loading parameter or static alignment. Of all the surrogate gait markers of dynamic load, the knee adduction angular momentum in terminal stance explained the most variance (20%) in the medial-to-lateral BMD ratio (adjusted r(2) = 0.196, P < 0.001). The knee adduction angular momentum for the entire stance phase explained 18% of the variance in the BMD ratio (adjusted r(2) = 0.178, P < 0.001), 10% more variance than explained by the overall peak knee adduction moment (adjusted r(2) = 0.081, P < 0.001). 18% of the variance in the BMD ratio was also explained by the knee alignment angle (adjusted r(2) = 0.183, P < 0.001), and the total explanatory power was increased to 22% when the knee adduction angular momentum in terminal stance was added (change in r(2) = 0.041, P < 0.05, total adjusted r(2) = 0.215, P < 0.001). The BMD ratio and its relationship to dynamic and static markers of loading were independent of height, weight, and the body mass index, demonstrating that both dynamic markers of knee loading as well as knee alignment explained variance in the tibial BMD ratio independent of body size.

Phenotypic characterization of chondrosarcoma-derived cell lines

Gene expression profiling of three chondrosarcoma derived cell lines (AD, SM, 105KC) showed an increased proliferative activity and a reduced expression of chondrocytic-typical matrix products compared to primary chondrocytes. The incapability to maintain an adequate matrix synthesis as well as a notable proliferative activity at the same time is comparable to neoplastic chondrosarcoma cells in vivo which cease largely cartilage matrix formation as soon as their proliferative activity increases. Thus, the investigated cell lines are of limited value as substitute of primary chondrocytes but might have a much higher potential to investigate the behavior of neoplastic chondrocytes, i.e. chondrosarcoma biology.

The radiographic joint space width in clinically normal hips: effects of age, gender and physical parameters

OBJECTIVE

The aim of the study was to assess the relationship of the radiographic joint space width (JSW) in the hip with age and a variety of physical parameters in a clinically non-arthritic population in order to identify potential age-related changes.

DESIGN

One hundred and eighteen patients (58F/60M, age range 20-79 years) who underwent supine abdominal radiography for non-rheumatological indications and had no hip pain were evaluated. Height, weight and leg lengths were measured. JSW was quantified manually by a dial caliper, and femoral head diameters were determined for each hip.

RESULTS

Overall, JSW was 3.61mm+/-0.58 (mean+/-SD) in the right (R) and 3.63mm+/-0.59 in the left (L) hip (range 2.34-6.1mm). There was no age-related decline in the JSW, either by decade (P=0.5 and 0.6, for R and L hips, respectively), or by individual age (Spearman's rho=-0.108 and 0.057, P=0.3 and 0.5 for R and L hips, respectively); similarly, no age-related changes were observed when each gender was analyzed separately. Women had significantly narrower hip JSW than men (P=0.001 and 0.01, R and L hips, respectively). However, gender was no longer significant after height was taken into account (P=0.26 and 0.45, for R and L hips, respectively). JSW correlated significantly with height, weight (which also correlated with height) (r=0.31/0.27 and 0.29/0.28 for height and weight R/L, respectively, P<0.004 for each), but not with body mass index (P=0.62 and 0.57, R and L, respectively). Hip JSW significantly correlated also with femoral head diameter and leg length (r=0.38/0.29 and 0.25/0.19 for femoral head and leg length, R/L, respectively).

CONCLUSIONS

No effect of aging was detected on the radiographic JSW of the hip among normal individuals even at advanced ages. In contrast, height, femoral head diameter and leg length were directly related to JSW.

Increased knee joint loads during walking are present in subjects with knee osteoarthritis

OBJECTIVE

This study tests the hypothesis that the peak external knee adduction moment during gait is increased in a group of ambulatory subjects with knee osteoarthritis (OA) of varying radiographic severity who are being managed with medical therapy. Tibiofemoral knee OA more commonly affects the medial compartment. The external knee adduction moment can be used to assess the load distribution between the medial and lateral compartments of the knee joint. Additionally, this study tests if changes in the knee angles, such as a reduced midstance knee flexion angle, or reduced sagittal plane moments previously identified by others as load reducing mechanisms are present in this OA group.

DESIGN

Thirty-one subjects with radiographic evidence of knee OA and medial compartment cartilage damage were gait tested after a 2-week drug washout period. Thirty-one normal subjects (asymptomatic control subjects) with a comparable age, weight and height distribution were also tested. Significant differences in the sagittal plane knee motion and peak external moments between the normal and knee OA groups were identified using t tests.

RESULTS

Subjects with knee OA walked with a greater than normal peak external knee adduction moment (P=0.003). The midstance knee flexion angle was not significantly different between the two groups (P=0.625) nor were the peak flexion and extension moments (P> 0.037).

CONCLUSIONS

Load reducing mechanisms, such as a decreased midstance knee flexion angle, identified by others in subjects with endstage knee OA or reduced external flexion or extension moments were not present in this group of subjects with knee OA who were being managed by conservative treatment. The finding of a significantly greater than normal external knee adduction moment in the knee OA group lends support to the hypothesis that an increased knee adduction moment during gait is associated with knee OA.

The clinical significance of tenascin-C splice variant expression in chondrosarcoma

OBJECTIVES

Tenascin-C (TNC) is an oligomeric glycoprotein of the extracellular matrix that is prominently expressed in malignant tumors. The purpose of this study was: (1) to determine the in vitro TNC splicing pattern in cultured human chondrocytes and chondrosarcoma cells, (2) to determine the in vivo TNC splicing pattern in clinical chondrosarcoma specimens, and (3) to perform survival analysis based on the TNC splicing pattern of the tumor specimens.

METHODS

Human articular chondrocytes and chondrosarcoma cells (cell line JJ012) were grown in a three-dimensional alginate bead system and harvested at two time points. Semiquantitative reverse transcription polymerase chain reaction (RT-PCR) was used to determine the in vitro TNC splicing pattern for the two cell types. Clinical chondrosarcoma specimens were obtained intra-operatively and underwent RT-PCR to determine the in vivo TNC splicing pattern. Specific immunohistochemical staining for the large TNC splice variant was performed on the clinical specimens. Survival analysis was used to determine the association between the specific TNC splicing pattern and survival.

RESULTS

The in vitro mRNA expression pattern of TNC in normal human articular chondrocytes was characterized by a high ratio of the small to the large splice variant (TNC(small):TNC(large)), whereas the in vitro mRNA expression pattern for cultured chondrosarcoma cells was characterized by a low TNC(small):TNC(large) ratio. Clinical chondrosarcoma specimens with a lower TNC(small):TNC(large) ratio showed a trend towards decreased survival. The TNC splicing pattern of these specimens was verified through specific immunohistochemical staining for the large TNC isoform.

CONCLUSIONS

The specific TNC splicing pattern may have clinical significance in chondrosarcoma. TNC expression may therefore play a future role in objective tumor grading and novel therapeutic approaches to this malignancy.

The knee adduction moment during gait in subjects with knee osteoarthritis is more closely correlated with static alignment than radiographic disease severity, toe out angle and pain

This study tested whether the peak external knee adduction moments during walking in subjects with knee osteoarthritis (OA) were correlated with the mechanical axis of the leg, radiographic measures of OA severity, toe out angle or clinical assessments of pain, stiffness or function. Gait analysis was performed on 62 subjects with knee OA and 49 asymptomatic control subjects (normal subjects). The subjects with OA walked with a greater than normal peak adduction moment during early stance (p = 0.027). In the OA group, the mechanical axis was the best single predictor of the peak adduction moment during both early and late stance (R = 0.74, p < 0.001). The radiographic measures of OA severity in the medial compartment were also predictive of both peak adduction moments (R = 0.43 to 0.48, p < 0.001) along with the sum of the WOMAC subscales (R = -0.33 to -0.31, p < 0.017). The toe out angle was predictive of the peak adduction moment only during late stance (R = -0.45, p < 0.001). Once mechanical axis was accounted for, other factors only increased the ability to predict the peak knee adduction moments by 10 18%. While the mechanical axis was indicative of the peak adduction moments, it only accounted for about 50% of its variation, emphasizing the need for a dynamic evaluation of the knee joint loading environment. Understanding which clinical measures of OA are most closely associated with the dynamic knee joint loads may ultimately result in a better understanding of the disease process and the development of therapeutic interventions.

Bone density, dynamic joint loading and joint degeneration. A review

Increased joint loading and elevated bone density may be involved in the initiation or progression of osteoarthritis. Here, we provide an introduction to the literature on this topic and describe recent studies from our laboratories on several cohorts of subjects who had or were scheduled to have a total hip replacement for unilateral end-stage osteoarthritis. This population is very useful for studying the development and progression of osteoarthritis because of the known higher incidence of osteoarthritis in the contralateral hip than in a normal population. Separate studies of the asymptomatic contralateral hip in these subjects have shown that radiographic signs of early osteoarthritis are associated with increased bone mineral density and some of the gait adaptations typically found in subjects with end-stage osteoarthritis. We have also shown in separate studies of similar populations that elevated bone mineral density is associated with a subsequent accelerated joint space narrowing rate and that elevated hip joint loads during gait are similarly associated with an accelerated narrowing rate. Major questions yet to be answered are how joint loading and bone density interact in the development and progression of joint degeneration.

Raynaud's phenomenon

Raynaud's phenomenon is characterised by episodic vasospasm of the fingers and toes typically precipitated by exposure to cold. Mild Raynaud's is common and is not usually a harbinger of clinically important disability; its onset, however, can be startling and uncomfortable for patients, and the well recognised association in some cases with systemic rheumatic conditions often precipitates aggressive assessments for underlying diseases. Advances in vascular physiology have shed light on the role of the endothelium as well as endothelium-independent mechanisms in the altered vasoregulation of Raynaud's. We review clinical aspects of the disorder and new insights with respect to pathophysiology, and we discuss potential new therapeutics based on the disease mechanism, such as prostacyclin analogues, serotonin antagonists, and calcitonin gene-related peptides.

Coronary artery disease in systemic lupus erythematosus: A review of the literature

CONTEXT

Coronary artery occlusive disease is a common though underappreciated complication of systemic lupus erythematosus (SLE), typically a disease of young women. A case of a premenopausal patient with SLE and an acute myocardial infarction is presented, and the etiology and management of coronary artery disease in SLE reviewed.

OBJECTIVES

To review the incidence, risk factors, pathology and treatment of coronary artery disease in systemic lupus erythematosus.

DATA SOURCES

MEDLINE search of articles in English-language journals from 1980 to 2000. The index words "systemic lupus erythematosus" and the following co-indexing terms were used: "coronary artery disease," "atherosclerosis," "vasculitis," "anticardiolipin antibodies," "antiphospholipid syndrome." SELECTION SYNTHESIS AND ABSTRACTION: Papers identified were reviewed and abstracted by the authors with a presentation of a summary.

RESULTS

The prevalence of coronary artery disease among women with SLE between the ages of 35 and 44 years is at least 50-fold greater than among age-matched control subjects. Of these, coronary atherosclerosis accounts for the vast majority of cases; vasculitis of the coronary arteries and other causes generally believed to be more typical of SLE are comparatively rare.

CONCLUSIONS

The evidence suggests that SLE is a significant risk factor for coronary atherosclerosis independent of the classic risk factors of hypertension, tobacco use, and hyperlipidemia.

Tenascin-C splice variant adhesive/anti-adhesive effects on chondrosarcoma cell attachment to fibronectin

Tenascin-C is an oligomeric glycoprotein of the extracellular matrix that has been found to have both adhesive and anti-adhesive properties for cells. Recent elucidation of the two major TNC splice variants (320 kDa and 220 kDa) has shed light on the possibility of varying functions of the molecule based on its splicing pattern. Tenascin-C is prominently expressed in embryogenesis and in pathologic conditions such as tumorogenesis and wound healing. Fibronectin is a prominent adhesive molecule of the extracellular matrix that is often co-localized with tenascin-C in these processes. We studied the chondrosarcoma cell line JJ012 with enzyme-linked immunoabsorbance assays, cell attachment assays and antibody-blocking assays to determine the adhesive/anti-adhesive properties of the two major tenascin-C splice variants with respect to fibronectin and their effect on chondrosarcoma cell attachment. We found that the small tenascin-C splice variant (220 kDa) binds to fibronectin, whereas the large tenascin-C splice variant (320 kDa) does not. In addition, the small tenascin-C splice variant was found to decrease adhesion for cells when bound to fibronectin, but contributed to adhesion when bound to plastic in fibronectin-coated wells. Antibody blocking experiments confirmed that both the small tenascin-C splice variant and fibronectin contribute to cell adhesion when bound to plastic. The large tenascin-C splice variant did not promote specific cell attachment. We hypothesize that the biologic activity of tenascin-C is dependent on the tissue-specific splicing pattern. The smaller tenascin-C isoform likely plays a structural and adhesive role, whereas the larger isoform, preferentially expressed in malignant tissue, likely plays a role in cell egress and metastasis.

Efficacy and safety of intraarticular sodium hyaluronate in knee osteoarthritis. ORTHOVISC Study Group

A prospective, multicenter, randomized, double-blind, controlled trial was conducted in 226 patients with knee osteoarthritis to evaluate the safety and efficacy of intraarticular injections of sodium hyaluronate. Patients were randomized to three weekly injections of 30 mg sodium hyaluronate or physiologic saline (control) and were observed for an additional 25 weeks. In comparison with the control group, among patients who completed at least 15 weeks of the study and whose Western Ontario and McMaster Universities Osteoarthritis Index pain score for the contralateral knee was less than 12 at baseline, sodium hyaluronate injection resulted in improvement in Western Ontario and McMaster Universities Osteoarthritis Index pain score, patient and investigator global assessments, and pain on standing from Weeks 7 to 27. Fifty-eight percent of patients treated with sodium hyaluronate achieved a 5-unit or greater improvement in mean pain score from Weeks 7 through 27, compared with 40% of control patients. In addition, nearly twice as many patients treated with sodium hyaluronate as with saline (30% versus 17%, respectively) achieved a net improvement of at least 7 units. In contrast to treatment with saline, Western Ontario and McMaster Universities Osteoarthritis Index pain score for the contralateral knee was inversely related to the magnitude of improvement after treatment with sodium hyaluronate. Few side effects were attributed to treatment, and no differences between treatment groups were seen in this respect (sodium hyaluronate, nine [8%]; saline, 11 [10%]). The incidence of injection site reactions was low (sodium hyaluronate, 1.2 %; saline, 1.5%). The results indicate that sodium hyaluronate treatment is well tolerated and produces statistically and clinically significant improvement of symptoms in patients with mild to moderate knee osteoarthritis in whom pain in the contralateral knee is relatively modest.

Two-year effects of alendronate on bone mineral density and vertebral fracture in patients receiving glucocorticoids: a randomized, double-blind, placebo-controlled extension trial

OBJECTIVE

To evaluate the continued efficacy and safety of alendronate (ALN) for up to 2 years in patients receiving glucocorticoids.

METHODS

This is a 12-month extension of a previously completed 1-year trial of daily ALN, performed to evaluate the effects of ALN over a total of 2 years in 66 men and 142 women continuing to receive at least 7.5 mg of prednisone or equivalent daily. All patients received supplemental calcium and vitamin D. The primary end point was the mean percentage change in lumbar spine bone mineral density (BMD) from baseline to 24 months. Other outcomes included changes in hip and total body BMD, biochemical markers of bone turnover, radiographic joint damage of the hands, and vertebral fracture incidence.

RESULTS

The mean (+/-SEM) lumbar spine BMD increased by 2.8 +/- 0.6%, 3.9 +/- 0.7%, and 3.7 +/- 0.6%, respectively, in the groups that received 5 mg, 10 mg, and 2.5/10 mg of ALN daily (P < or = 0.001) and decreased by -0.8 +/- 0.6% in the placebo group (P not significant) over 24 months. In patients receiving any dose of ALN, BMD was increased at the trochanter (P < or = 0.05) and maintained at the femoral neck. Total body BMD was increased in patients receiving 5 or 10 mg ALN (P < or = 0.01). These 2 dose levels of ALN were more effective than placebo at all sites (P < or = 0.05). Bone turnover markers (N-telopeptides of type I collagen and bone-specific alkaline phosphatase) decreased 60% and 25%, respectively, during treatment with ALN (P < or = 0.05). There were fewer patients with new vertebral fractures in the ALN group versus the placebo group (0.7% versus 6.8%; P = 0.026). The safety profile was similar between treatment groups.

CONCLUSION

Alendronate is an effective, well-tolerated therapy for the prevention and treatment of glucocorticoid-induced osteoporosis, with sustained treatment advantages for up to 2 years.

Alterations in the regulatory pathway involving p16, pRb and cdk4 in human chondrosarcoma

The G1 regulatory pathway involving p16, pRb and cdk4 in the cell cycle has been investigated in human chondrosarcoma. The protein expression of p16, pRb and cdk4 was analyzed by Western blot in cultured cells from eight chondrosarcomas and in two chondrosarcoma cell lines. Both cell lines and one other sample were negative for p16. Moreover, one of the cell lines was pRb-negative and showed a high expression of cdk4 as well. In the other cell line and in three other samples pRb of expected size were detected in addition to a shorter form of the protein. To further investigate the reasons for down-regulation of the p16 protein, the p16-coding gene CDKN2 was analyzed by polymerase chain reaction (PCR), methyl-specific PCR (MSP) and sequencing in all tumor samples as well as in corresponding tumor tissues from three of the samples. The p16-negative samples were all found to have homozygous deletion of CDKN2. Another sample showed partial gene methylation and a heterozygous position in codon 148 was detected in one sample. The same base substitution was also found in two of the tissue samples. Finally, cytogenetic analysis of the samples with homozygously deleted CDKN2 revealed multiple structural abnormalities in all three cases. In conclusion, the p16/pRb/cdk4 pathway may play an important role in the pathogenesis of some chondrosarcomas.

Two-year effects of alendronate on bone mineral density and vertebral fracture in patients receiving glucocorticoids: a randomized, double-blind, placebo-controlled extension trial

OBJECTIVE

To evaluate the continued efficacy and safety of alendronate (ALN) for up to 2 years in patients receiving glucocorticoids.

METHODS

This is a 12-month extension of a previously completed 1-year trial of daily ALN, performed to evaluate the effects of ALN over a total of 2 years in 66 men and 142 women continuing to receive at least 7.5 mg of prednisone or equivalent daily. All patients received supplemental calcium and vitamin D. The primary end point was the mean percentage change in lumbar spine bone mineral density (BMD) from baseline to 24 months. Other outcomes included changes in hip and total body BMD, biochemical markers of bone turnover, radiographic joint damage of the hands, and vertebral fracture incidence.

RESULTS

The mean (+/-SEM) lumbar spine BMD increased by 2.8 +/- 0.6%, 3.9 +/- 0.7%, and 3.7 +/- 0.6%, respectively, in the groups that received 5 mg, 10 mg, and 2.5/10 mg of ALN daily (P < or = 0.001) and decreased by -0.8 +/- 0.6% in the placebo group (P not significant) over 24 months. In patients receiving any dose of ALN, BMD was increased at the trochanter (P < or = 0.05) and maintained at the femoral neck. Total body BMD was increased in patients receiving 5 or 10 mg ALN (P < or = 0.01). These 2 dose levels of ALN were more effective than placebo at all sites (P < or = 0.05). Bone turnover markers (N-telopeptides of type I collagen and bone-specific alkaline phosphatase) decreased 60% and 25%, respectively, during treatment with ALN (P < or = 0.05). There were fewer patients with new vertebral fractures in the ALN group versus the placebo group (0.7% versus 6.8%; P = 0.026). The safety profile was similar between treatment groups.

CONCLUSION

Alendronate is an effective, well-tolerated therapy for the prevention and treatment of glucocorticoid-induced osteoporosis, with sustained treatment advantages for up to 2 years.

Osteoarticular tuberculosis: current diagnosis and treatment

Tuberculous synovitis frequently presents as a monoarthritis of weight-bearing joints such as the hip, knee, or ankle. Owing to its low incidence in developed countries, the diagnosis is often delayed for months to years. Early diagnosis with a synovial biopsy permits prompt antituberculous therapy and substantially improves the prospect of preservation of joint structure and function. Initial treatment typically includes combination therapy with four drugs (isoniazid, rifampin, pyrazinamide, and streptomycin or ethambutol) because of the frequency of isoniazid resistance. Antimicrobial therapy should be of at least 9 months' duration, longer in immunocompromised hosts. Partial synovectomy and other surgical procedures should be restricted to joints with severe cartilage destruction, large abscesses, joint deformity, multiple drug resistance, or atypical mycobacteria.

Scleroderma lung: pathogenesis, evaluation, and current therapy

Interstitial lung disease (ILD) is now the most common cause of mortality in scleroderma, although its pathogenesis remains poorly understood. Management requires early detection and treatment before the onset of lung fibrosis. In a number of uncontrolled studies, the combination of daily oral cyclophosphamide and low-dose prednisone appears to be effective, although these conclusions have yet to be confirmed.

Marshall Urist Award. Interstitial collagenase gene expression correlates with in vitro invasion in human chondrosarcoma

Matrix metalloproteinases contribute to the processes of local invasion and metastasis by providing cells with the ability to traverse tissue boundaries. The levels of gene expression were quantitated for matrix metalloproteinases-1 and tissue inhibitors of metalloproteinases-1 in human chondrosarcoma cell lines, and the results were correlated with cell differentiation, collagenase activity, and in vitro invasion. Three well characterized human cell lines were used in this study, with the level of chondrocytic differentiation confirmed to be JJ012, FS090, and 105KC in increasing order on the basis of aggrecan and collagen gene expression. The matrix metalloproteinases-1/tissue inhibitors of metalloproteinases-1 ratio correlated with the level of differentiation in an inverse fashion. Collagenase activity paralleled matrix metalloproteinases-1/tissue inhibitors of metalloproteinases-1 gene expression and was associated with a more invasive phenotype in an in vitro assay. In this report, matrix metalloproteinase-1 and tissue inhibitors of metalloproteinases-1 expression in human chondrosarcoma tumor cell lines were quantitated, and it was shown that interstitial collagenase gene expression correlates inversely with chondrocytic differentiation. Differences in collagenase activity and in vitro invasion correlate inversely with the level of differentiation. These findings are consistent with the hypothesis that collagenase activity is associated with a poorer prognosis in chondrosarcoma by facilitating cell egress from the tumor matrix.

Knee pain and joint loading in subjects with osteoarthritis of the knee

Although treatments for osteoarthritis of the knee are often directed at relieving pain, pain may cause patients to alter how they perform activities to decrease the loads on the joints. The knee-adduction moment is a major determinant of the load distribution between the medial and lateral plateaus. Therefore, the interrelationship between pain and the external knee-adduction moment during walking may be especially important for understanding mechanical factors related to the progression of medial tibiofemoral osteoarthritis. Fifty-three subjects with symptomatic radiographic evidence of osteoarthritis of the knee were studied. These subjects were a subset of those enrolled in a double-blind study in which gait analysis and radiographic and clinical evaluations were performed after a 2-week washout of anti-inflammatory and analgesic treatment. The subjects then took a nonsteroidal anti-inflammatory drug, acetaminophen, or placebo for 2 weeks, and the gait and clinical evaluations were repeated. The change in the peak external adduction moment between the two evaluations was inversely correlated with the change in pain (R = 0.48, p < 0.001) and was significantly different between those whose pain increased (n = 7), decreased (n = 18), or remained unchanged (n = 28) (p = 0.009). Those with increased pain had a significant decrease in the peak external adduction (p = 0.005) and flexion moments (p = 0.023). In contrast, the subjects with decreased pain tended to have an increase in the peak external adduction moment (p = 0.095) and had a significant increase in the peak external extension moment (p = 0.017). The subjects whose pain was unchanged had no significant change in the peak external adduction (p = 0.757), flexion (p = 0.234), or extension (p = 0.465) moments. Thus, decreases in pain among patients with medial tibiofemoral osteoarthritis were related to increased loading of the degenerative portion of the joints. Additional long-term prospective studies are needed to determine whether increased loading during walking actually results in accelerated progression of the disease.

Quantification of progressive joint space narrowing in osteoarthritis of the hip: longitudinal analysis of the contralateral hip after total hip arthroplasty

OBJECTIVE

The rate of progressive joint space narrowing in the contralateral hip after total hip arthroplasty (THA) for osteoarthritis (OA) and the factors which may predispose patients to more aggressive joint space narrowing remain undefined. The current study sought to evaluate the rate and pattern of, and risk factors for, progressive joint space narrowing in the contralateral hip after THA for OA.

METHODS

Each patient who underwent THA for OA in 1984-1985 was followed up longitudinally, and annual anteroposterior (AP) pelvis radiographs were obtained. The radiographic joint space width (JSW) of each contralateral hip joint was quantified, and the rates of JSW narrowing were determined. Evaluation of potential risk factors for accelerated progression of joint space narrowing included age, sex, side of surgery, weight, height, body mass index (BMI), hip pain, etiology of OA, and Kellgren/Lawrence radiographic grade.

RESULTS

Ninety-nine patients and 619 AP pelvis radiographs were evaluated. The median initial JSW was 3.48 mm (interquartile range 1.55). JSW declined in a linear manner at a median rate of 0.10 mm/year. The rate of decline between baseline and followup in 20 months was predictive of the overall slope. Two subpopulations were identified. Eighty-five percent of patients maintained a slow decline in JSW (< or =0.2 mm/year), and 15% exhibited an accelerated decline in JSW (>0.2 mm/year). Kellgren/ Lawrence radiographic grade > or =2 and a diagnosis of primary OA were each associated with a more rapid decline in JSW (P = 0.006 and P = 0.02, respectively). Initial JSW, age, sex, weight, height, BMI, and hip pain were not risk factors for rapid decline in JSW.

CONCLUSION

Radiographic hip JSW may be reliably quantified and followed up longitudinally using standard AP radiographs. Progression of JSW narrowing in the contralateral hip after THA for OA proceeds in a linear manner over several years. A subpopulation of patients with accelerated narrowing of contralateral JSW may be identified within 20 months, and may represent a suitable population with which to assess the potential efficacy of new disease-modifying agents.

Bone mineral density varies as a function of the rate of joint space narrowing in the hip

OBJECTIVE

To determine whether patients with a rapid rate of joint space narrowing (JSN) in the hip have higher initial bone mineral density (BMD) in the proximal femur and/or lumbar spine than corresponding patients with a slow rate of JSN.

METHODS

Twenty-eight patients undergoing unilateral total hip replacement (THR) for osteoarthritis (OA), but whose contralateral hips were asymptomatic and had minimal or no radiographic OA, were evaluated. The contralateral proximal femur (i.e., non-operated hip) and lumbar spine were scanned by dual energy x-ray absorptiometry at baseline (prior to THR) and at 2 years. The rate of JSN was determined by serial longitudinal quantification of the joint spaces over the 2 year period following THR from conventional radiographs, and the patients were divided into a group with a slow rate of JSN (< or = 0.2 mm/yr, n = 20) and a group with a rapid rate of JSN (> 0.2 mm/yr, n = 8).

RESULTS

The baseline BMD z and t scores at the femoral neck, Ward's triangle, and lumbar spine of the patients with subsequent rapid rates of JSN were significantly higher than those of patients with slower rates (p < 0.05). There was no difference between the rapid and slow narrowers at the greater trochanter (p > 0.2). Age, sex, weight, height, body mass index, Kellgren- Lawrence scores, and initial joint space width were not significantly different between the 2 groups.

CONCLUSION

Patients with a rapid rate of JSN of the asymptomatic hip after unilateral THR are characterized by elevated local and remote BMD. The local elevation in BMD implies that increased local bone density may contribute to or serve as a marker for increased risk of development of OA (assuming that JSN can be used as a predictive marker). The presence of elevated BMD in the spine suggests that there are systemic as well as local aspects of OA pathogenesis, at least in patients with one THR and rapid JSN in the contralateral hip.

Multidrug resistance-1 and p-glycoprotein in human chondrosarcoma cell lines: expression correlates with decreased intracellular doxorubicin and in vitro chemoresistance

We report on two chondrosarcoma cell lines, FS and AQ, that may be used as models of multidrug resistance in chondrosarcoma. Multidrug resistance-1 expression was assayed with reverse transcription-polymerase chain reaction. Immunostaining for the multidrug resistance-1 product, P-glycoprotein, was performed with the monoclonal antibody C494. Intracellular levels of doxorubicin were measured by fluorescent emission at 590 nm after 1 hour of incubation with the agent and again after 1, 2, and 4-hour washout periods. Chemosensitivity was assayed by staining micropellet cultures of AQ and FS cells with fluorescein acetate before and after the cells were exposed to varying doses of doxorubicin for 48 hours. Cytotoxicity was assessed by comparison of computer-processed images before and after treatment. The FS cell line was positive for multidrug resistance-1 expression, stained heavily for P-glycoprotein, and had significantly lower intracellular levels of doxorubicin than the AQ cell line, which was negative for multidrug resistance-1 and P-glycoprotein. Chemosensitivity testing showed that the FS cell line was significantly more resistant to doxorubicin than was the AQ cell line at all doses tested. Our results show that multidrug resistance-1 expression in a human chondrosarcoma cell line results in resistance to doxorubicin in vitro.

The Prosorba column for treatment of refractory rheumatoid arthritis: a randomized, double-blind, sham-controlled trial

OBJECTIVE

To evaluate the efficacy and safety of the Prosorba column as a treatment for rheumatoid arthritis (RA) in patients with active and treatment-resistant (refractory) disease.

METHODS

A sham-controlled, randomized, double-blind, multicenter trial of Prosorba versus sham apheresis was performed in patients with RA who had failed to respond to treatment with methotrexate or at least 2 other second-line drugs. Patients received 12 weekly treatments with Prosorba or sham apheresis, with efficacy evaluated 7-8 weeks after treatment ended. Patients were characterized as responders if they experienced improvement according to the American College of Rheumatology (ACR) response criteria at the efficacy time point. A data safety monitoring board (DSMB) evaluated interim analyses for the possibility of early completion of the trial.

RESULTS

Patients in the trial had RA for an average of 15.5 years (range 1.7-50.6) and had failed an average of 4.2 second-line drug treatments prior to entry. After the completion of treatment of 91 randomized patients, the DSMB stopped the trial early due to successful outcomes. Of the 47 patients in the Prosorba arm, 31.9% experienced ACR-defined improvement versus 11.4% of the 44 patients in the sham-treated arm (P = 0.019 after adjustment for interim analysis). When results from 8 additional patients, who had completed blinded treatments at the time of DSMB action, were added to the analysis (n = 99), results were unchanged. The most common adverse events were a short-term flare in joint pain and swelling following treatment, a side effect that occurred in most subjects at least once in both treatment arms. Other side effects, although common, occurred equally as frequently in both treatment groups.

CONCLUSION

Apheresis with the Prosorba column is an efficacious treatment for RA in patients with active disease who have failed other treatments.

Therapeutic approaches to osteoarthritis

Management is multifaceted: Palliation of pain should be accompanied by physical and occupational therapy and use of adaptive devices to improve performance. New techniques aim to interrupt disease progression and to induce biologic repair.

Chromosome 9 related aberrations and deletions of the CDKN2 and MTS2 putative tumor suppressor genes in human chondrosarcomas

Deletions on the short arm of chromosome 9 (9p21 region) have been reported in a number of hematopoietic and solid tumors. These aberrations on 9p have been previously associated with the loss of the interferon gene cluster and the gene for methylthioadenosine phosphorylase (MTAP), localized to the 9p21-22 region. Recently, two putative tumor suppressor gene(s) CDKN2 and MTS2 have been mapped to the 9p21 region, and shown to be deleted in a large number of tumors including leukemias, melanomas, bladder cancers and brain tumors. We have previously reported a similar 9p21 abnormality and deletions of the CDKN2 and MTS2 genes in a myxoid chondrosarcoma cell line and its subclones. In this study we report consistent abnormalities of chromosome 9 in additional chondrosarcomas examined by a detailed cytogenetic and molecular analysis. Seven chondrosarcoma cell lines, one primary chondrosarcoma, and a benign chondroma were examined. Four of the seven tumor cell lines examined showed grossly visible aberrations of chromosome 9. Molecular analysis of these chondrosarcoma cell lines revealed hemizygous deletions of the interferon genes, and the absence of the MTAP gene, protein or activity. In addition, four of the seven chondrosarcoma cell lines also showed deletions of the CDKN2 and/or MTS2 putative tumor suppressor genes, or the absence of the CDKN2 protein product. No such chromosome 9 related aberrations were detected in the benign chondroma. These data suggest that chromosome 9p21 abnormality, and deletions of the CDKN2 and MTS2 tumor suppressor genes may be a significant event in the development of chondrosarcomas.

Partial deletions of the CDKN2 and MTS2 putative tumor suppressor genes in a myxoid chondrosarcoma

Cytogenetic abnormalities of chromosome 9 (9p21) have been reported in a large number of tumors that include malignant melanomas, gliomas, lung cancers and leukemias. These aberrations on 9p have been previously shown to involve the loss of the interferon gene cluster and the gene for methylthioadenosine phosphorylase (MTAP), both of which have been mapped to the 9p21 region. Recently, two putative tumor suppressor gene(s) CDKN2 and MTS2, have been mapped to the 9p21 region, and have been shown to be deleted in a large number of hematopoietic and solid malignancies. In this study we report a cytogenetic and a detailed molecular analysis of a myxoid chondrosarcoma cell line 105KC and its clonal derivatives 105AJ, 105AJ1.1, 105AJ3.1, and 105AJ5.1. Specifically, we have demonstrated chromosome 9p21 related abnormalities by cytogenetic analysis, the associated loss of the interferon gene cluster, and the loss of the immunoreactive MTAP protein and activity. In addition, we have also shown the presence of deletions involving the CDKN2 and the MTS2 putative tumor suppressor genes in these chondrosarcoma cell lines. The above studies were extended to other chondrosarcoma cell lines and primary tumors, where similar deletions of the CDKN2 and MTS2 genes were found to be present (unpublished data). This suggests a potential role for the involvement of the CDKN2 and MTS2 putative tumor suppressor genes in the development of chondrosarcomas.