OP0168 DEVELOPMENT OF AN ULTRASOUND SCORING SYSTEM FOR CPPD EXTENT: RESULTS FROM A DELPHI PROCESS AND WEB-RELIABILITY EXERCISE BY THE OMERACT US WORKING GROUP

Background

Ultrasound (US) has proven to be an excellent imaging technique for detecting calcium pyrophosphate (CPP) deposition disease (CPPD); it is also widely available and inexpensive and can be performed during the clinic visit making it the preferred imaging modality for many rheumatologists. However, no validated grading systems have yet been developed allowing for a quantification of the extent of crystal deposition in CPPD.

Objectives

The aim of this study was to develop a scoring system for the quantification of CPP deposition at a patient level according to the OMERACT framework.

Methods

As part of the OMERACT methodology, we performed a systematic literature review (SLR) and meta-analysis aimed to estimate the prevalence of CPP deposition in peripheral joints by imaging, in order to identify relevant joints for CPPD monitoring. A preliminary survey was also circulated among the members of the OMERACT US – CPPD working group to collect their own suggestions according to their personal experience. Subsequently, a Delphi survey was prepared and circulated between members of the group, including statements that reflected both the results of the SLR and of the preliminary survey. In total, 32 statements were generated regarding the type of scoring for single structures, the sites to be included, the final scoring at patient level, and the scanning technique. Participants were asked to reply on a 5-point Likert scale (1, strongly disagree to 5, strongly agree) and agreement was achieved when 4 and 5 grades reached 75% or more of concordance. In case of disagreement, new statements were proposed according to the members’ suggestions and circulated for voting in a subsequent round. After agreement of a scoring system, the validation process began. Two rounds of a web-based exercise on static images were conducted on 120 images representing equally all sites under investigation and all degrees of crystal deposition, to assess the intra- and inter-reader reliability of the new scoring system. Representative images of the scoring system were visible throughout the entire exercise in order to facilitate the scoring of the lesions.

Results

Three Delphi rounds were needed to reach agreement on all items. 32/41 members of the OMERACT US-CPPD working group replied in the first round, 26/32 in the second, and 25/26 in the third round. Twenty statements were approved in the first round, 3 in the second, and 3 in the third round. Only the knees (menisci and hyaline cartilage) and the triangular fibrocartilage of the wrist were included in the final score, using a four-grade system (0-3). It was decided that each anatomical structure should be scored separately and then also summed in order to define the joint score. The sum of the assessed joints was the total score at patient level. The final scoring system with the definitions and the relative technical notes is represented in Figure 1. 33/41 members participated to the reliability exercise. The inter-reader reliability of the scoring was substantial (kappa of 0.72), and the intra-reader reliability was almost perfect (kappa of 0.82).

Conclusion

This is the first study for developing a scoring system for the extent of CPP crystal deposition in patients with CPPD. The scoring system demonstrated to be reliable in static images. The next step of the validation process is to assess the reliability of the scoring system in a patient-based exercise. This study represents a fundamental step in the OMERACT process of validating US as an outcome measure instrument, and above proposed scoring system will hopefully provide a useful tool for clinical practice and research.

Disclosure of Interests

None declared

POS0846 MORTALITY OUTCOME OF ACUTE MYOCARDIAL INFRACTION IN PATIENTS WITH IDIOPATHIC INFLAMMATORY MYOPATHIES, A QUALITATIVE APPROACH ANALYSIS OF THE NATIONAL INPATIENT SAMPLE FROM 2016-2019

Background

The pathophysiology of cardiovascular damage in myositis is a multi-factorial process. Myositis can cause inflammation of the myocardium with accelerated coronary atherosclerosis,the risk of cardiovascular disease in hospitalized patients with idiopathic dermatomyositis was 15% from 2016-17.1

Objectives

To investigate the quality of care of acute myocardial infarctions (AMI) events in myositis compared to non-myositis patients across the United States categorized by the types of hospitals, probability of myocardial events, and mortality outcome from the NIS from 2016-19.

Methods

We used SAS statistical software to perform analyses on the NIS database (2016-19) in the US. Adults with AMI and myositis at the time of discharge were identified by International Statistical Classification of Disease 10 (ICD-10) codes. Latent class analysis was used to empirically identify hospital groups across different regions in the U.S where myositis patients received their cardiac care. Once hospital groups were determined, patients were compared with and without myositis in each hospital group. Probabilities of AMI event and mortality among myositis patients were compared using logistic regression analysis.

Results

The NIS sample included 38,363 myositis patients and 24,179,176 non-myositis patients. Three hospital groups were identified, the first two represented inner-city hospitals, with the second group of hospitals tending to be larger and serving lower income patients (Table 1). The third hospital group represented rural hospitals, though they also tended to perform fewer cardiac procedures. Importantly, this third group was about half as likely to identify myositis patients and more likely to identify the unrelated confounder conditions. (myositis=0.10%, confounder=41.0%) This provides evidence that rural hospitals may lack the training and resources to properly care for myositis patients, as hypothesized.

Table 1.

Hospital Characteristics and Patient Outcomes

TraitGroup 1Group 2Group 3Group 1Group 2Group 3OverallPatient Diagnoses (%)MI Event (%)Myositis ^0.220.180.10Myositis patients19.0211.319.89Myocardial infarction ±8.977.0210.85Non-myositis patients22.1312.0512.59Unrelated confounder *34.6435.8741.60OR0.860.940.790.83Catheter procedures2.522.390.84p0.0026< 0.0001< 0.0001<0.0001Hospital CharacteristicsMortality (%)Bedsize (1 = small to 3 = large)1.311.361.86Myositis patients6.125.1510.02Rural setting (%)7.080.6437.00Non-myositis patients9.776.828.95Transfers out (%)20.0320.6117.12OR0.630.761.120.60Patient income quartiles (M)2.101.752.12p0.0001< 0.0001< 0.0001< 0.0001

^ Based on ICD 10 codes under M33, M60 and G72 groups

± Based on ICD 10 codes under I21group

* Confounder diagnoses: hypertension, hyperlipidemia, diabetes mellitus, tobacco/alcohol/substance abuses, obesity, rheumatoid arthritis, systemic lupus erythematosus and gout.

Overall, the odd ratio (OR) for myositis patients to have AMI event was 0.83 (p < 0.0001); among those who had AMI events, OR for mortality was 0.60 (p < 0.0001). Patients who received care at more rural hospitals (group 3) were at heightened mortality risk (OR=1.12, p < 0.0001). Opposite to the patient experiences in urban hospitals, the unique risk of mortality to myositis patients in rural hospitals was heightened (OR = 1.88, p < 0.0001).

Conclusion

Myositis was not associated with higher AMI events and mortality outcomes in this nationwide hospitalization cohort. Hospitals in rural locations had fewer diagnosed cases of myositis, catheter procedure and transfer out rate may have contributed to higher AMI mortality outcome in group 3. Further studies should examine if catheter procedure mortality outcome of AMI event in myositis differ in the three hospital groups.

References

[1]Pavon MR, and et al. Reasons for Hospitalization and In-Hospital Mortality in Adults With Dermatomyositis and Polymyositis.2021 Jun 18. J Clin Rheumatol. 2021;10.1097

Disclosure of Interests

None declared

POS1124 IDENTIFYING POTENTIAL CLASSIFICATION CRITERIA FOR CALCIUM PYROPHOSPHATE DEPOSITION DISEASE (CPPD): RESULTS FROM THE INITIAL PHASES

Background:

Classification criteria for calcium pyrophosphate deposition disease (CPPD) will facilitate clinical research on this common crystalline arthritis. ACR/EULAR are jointly sponsoring development of CPPD classification criteria using a multi-phase process.

Objectives:

To report preliminary results from the first two phases of a four-phase process for developing CPPD classification criteria.

Methods:

CPPD classification criteria development is overseen by a 12-member Steering Committee. Item generation (Phase I) included a scoping literature review of five literature databases and contributions from a 35-member Combined Expert Committee and two Patient Research Partners. Item reduction and refinement (Phase II) involved a Combined Expert Committee meeting, discussions among Clinical, Imaging, and Laboratory Advisory Groups, and an item rating exercise to assess the influence of individual items toward classification. The Steering Committee reviewed the modal rating score for each item (range -3 [strongly pushes away from CPPD] to +3 [strongly pushes toward CPPD]) to determine items to retain for future phases of criteria development.

Results:

Item generation yielded 420 items (312 from the literature, 108 from experts/patients). The Advisory Groups eliminated items they agreed were unlikely to distinguish between CPPD and other forms of arthritis, yielding 127 items for the item rating exercise. Fifty-six items, most of which had a modal rating of +/- 2 or 3, were retained for future phases (see Table 1). As numerous imaging items were rated +3, the Steering Committee recommended focusing on imaging of the knee, wrist, and one additional affected joint for calcification suggestive of CPP crystal deposition.

Conclusion:

The ACR/EULAR CPPD classification criteria working group has adopted both data- and expert-driven approaches, leading to 56 candidate items broadly categorized as clinical, imaging, and laboratory features. Remaining steps for criteria development include domain establishment, item weighting through a multi-criteria decision analysis exercise, threshold score determination, and criteria validation.

Table 1.

Categories of items retained for future phases of classification criteria development

Age in decade at symptom onsetAcute inflammatory arthritis (e.g. knee, wrist, 1st MTP joint*)Recurrence and pattern of joint involvement (e.g. 1 self-limited episode, >1 self-limited episode)Physical findings (e.g. palpable subcutaneous tophus*, psoriasis*)Co-morbidities and family history (e.g. Gitelman disease, hemochromatosis, familial CPPD)Osteoarthritis location and features (e.g. 2nd or 3rd MCP joint, wrist)Synovial fluid findings (e.g. CPP crystals present, CPP crystals absent on 1 occasion* or 2 occasions*, monosodium urate crystals present*)Laboratory findings (e.g. hypomagnesemia, hyperparathyroidism, rheumatoid factor*, anti-CCP*)Plain radiograph: calcification in regions of fibro- or hyaline cartilage+Plain radiograph: calcification of the synovial membrane/capsule/tendon+Conventional CT: calcification in regions of fibro- or hyaline cartilage+Conventional CT: calcification of the synovial membrane/capsule/tendon+Ultrasound: CPP crystal deposition in fibro- or hyaline cartilage+Ultrasound: CPP crystal deposition in synovial membrane/capsule/tendons+Dual-energy CT: CPP crystal deposition in fibro- or hyaline cartilage+Dual-energy CT: CPP crystal deposition in synovial membrane/capsule/tendon+

*Potential negative predictor +Assessed in the knee, wrist, and/or 1 additional affected joint

Disclosure of Interests:

Sara Tedeschi Consultant of: NGM Biopharmaceuticals, Tristan Pascart: None declared, Augustin Latourte Consultant of: Novartis, Cattleya Godsave: None declared, Burak Kundaki: None declared, Raymond Naden: None declared, William Taylor: None declared, Nicola Dalbeth Speakers bureau: Abbvie and Janssen, Consultant of: AstraZeneca, Dyve, Selecta, Horizon, Arthrosi, and Cello Health, Tuhina Neogi: None declared, Fernando Perez-Ruiz: None declared, Ann Rosenthal: None declared, Fabio Becce Consultant of: Horizon Therapeutics, Grant/research support from: Siemens Healthineers, Eliseo Pascual: None declared, Mariano Andrés: None declared, Thomas Bardin: None declared, Michael Doherty: None declared, Hang Korng Ea: None declared, Georgios Filippou: None declared, John FitzGerald: None declared, Marwin Gutierrez: None declared, Annamaria Iagnocco: None declared, Tim Jansen Speakers bureau: Abbvie, Amgen, BMS, Grunenthal, Olatec, Sanofi Genzyme, Consultant of: Abbvie, Amgen, BMS, Grunenthal, Olatec, Sanofi Genzyme, Minna Kohler Speakers bureau: Lilly, Consultant of: Novartis, Frederic Lioté: None declared, Mark Matza: None declared, Geraldine McCarthy Consultant of: PK Med, Roberta Ramonda: None declared, Anthony Reginato: None declared, Pascal Richette: None declared, Jasvinder Singh Speakers bureau: Simply Speaking, Consultant of: Crealta/Horizon, Medisys, Fidia, UBM LLC, Trio health, Medscape, WebMD, Adept Field Solutions, Clinical Care options, Clearview healthcare partners, Putnam associates, Focus forward, Navigant consulting, Spherix, Practice Point communications, Francisca Sivera: None declared, Alexander So: None declared, Lisa Stamp: None declared, Janeth Yinh: None declared, Chio Yokose: None declared, Robert Terkeltaub Consultant of: Sobi, Horizon Therapeutics, Astra-Zeneca, Selecta, Grant/research support from: Astra-Zeneca, Hyon Choi: None declared, Abhishek Abhishek Consultant of: NGM Biopharmaceuticals.

Lipid excess affects chaperone-mediated autophagy in hypothalamus

Obesity is a major health problem worldwide. Overweight and obesity directly affect health-related quality of life and also have an important economic impact on healthcare systems. In experimental models, obesity leads to hypothalamic inflammation and loss of metabolic homeostasis. It is known that macroautophagy is decreased in the hypothalamus of obese mice but the role of chaperone-mediated autophagy is still unknown. In this study, we aimed to investigate the role of hypothalamic chaperone-mediated autophagy in response to high-fat diet and also the direct effect of palmitate on hypothalamic neurons. Mice received chow or high-fat diet for 3 days or 1 week. At the end of the experimental protocol, chaperone-mediated autophagy in hypothalamus was investigated, as well as cytokines expression. In other set of experiments, neuronal cell lines were treated with palmitic acid, a saturated fatty acid. We show that chaperone-mediated autophagy is differently regulated in response to high-fat diet intake for 3 days or 1 week. Also, when hypothalamic neurons are directly exposed to palmitate there is activation of chaperone-mediated autophagy. High-fat diet causes hypothalamic inflammation concomitantly to changes in the content of chaperone-mediated autophagy machinery. It remains to be studied the direct role of inflammation and lipids itself on the activation of chaperone-mediated autophagy in the hypothalamus in vivo and also the neuronal implications of chaperone-mediated autophagy inhibition in response to obesity.

AB1179 EMERGENCY DEPARTMENT LENGTH OF STAY FOR PATIENTS WITH ACUTE GOUT

Background:

Emergency department (ED) visits for acute gout increased by approximately 20% between 2006 and 2014 in the United States. (1) Reducing ED length of stay (LOS) can help improve health outcomes, and reduce ED crowding and cost of care for patients with gout.

Objectives:

The aim of our study was to assess ED LOS and to identify factors associated with prolonged ED LOS in patients with acute gout.

Methods:

In this retrospective analysis, we included the first ED visit of adult patients (>18

years) with acute gout who presented to the 3 EDs affiliated with Lifespan Health Systems, the largest healthcare provider in Rhode Island. Our study period was 3/30/2015 to 9/30/2017.

We calculated ED LOS as the time spent by patients in the ED until they were discharged. Patients presenting to the ED and subsequently admitted to the hospital were excluded given the differential effect of systems factors in these patients. We assessed the following factors’ association with being in the upper quartile of ED LOS: (a) Patient factors – demographics, comorbidities and clinical presentation of gout (number of joints involved, severity as gauged by an ED triage nurse on a scale of 1 to 5; 1 being the worst) and (b) systems factors – time of day, day of the week, and time of year at presentation to the ED, teaching versus non-teaching hospital setting, and performing an arthrocentesis. We performed univariate and multivariable analyses to identify factors associated with prolonged ED LOS in patients with acute gout.

Results:

A total of 355 patients (mean age 56.6 ± 16.03 years, 81.3% males) were included. The median ED LOS was 2.65 hours (1.75, 4.3 hours). A quarter of the patients spent more than 4.3 hours in the ED; the national average across all medical illnesses being 3.7 hours (2). In the univariate analysis, older age (> 65 years), comorbidities (hypertension, congestive heart failure), worse ED severity score, procedural delays, and teaching hospital setting were associated with being in the upper quartile of ED LOS. In a multivariable analysis, age >65 years, procedural delays, and worse ED acuity score continued to be associated with longer ED LOS.

Conclusion:

In our study settings, patients with acute gout spent a longer time in the ED than the national median of 120-150 minutes. (2) We noted that older age and higher acuity score in addition to procedural delays led to longer length of stay in the ED. The results of our study should guide future interventions to reduce ED LOS for patients with acute gout.

References:

[1] Mithal, A., & Singh, G. (2018). OP0185 Emergency department visits for gout: a dramatic increase in the past decade

[2]Centers for Disease Control and Prevention. (2014). QuickStats: median emergency department (ED) wait and treatment times, by triage level–National Hospital Ambulatory Medical Care Survey, United States, 2010-2011. Morb Mortal Wkly Rep, 63,439. (https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6319a8.htm)

Disclosure of Interests:

None declared

Gene Expression of Matrix Metalloproteinases and their Inhibitors (TIMPs) in Meningiomas of Dogs

BACKGROUND

Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are considered to be key mediators of tumor invasion and metastasis. MMP-2 and MMP-9 are expressed in meningiomas of dogs, but TIMP expression, and variations of specific MMP/TIMP ratios still are unknown in this tumor.

HYPOTHESIS/OBJECTIVES

Expression of MMP/TIMP might increase progressively from grade I to grade III meningioma. Therefore, genetic expression of MMP-2 and MMP-9, and specific TIMP-2 and TIMP-1, respectively, has been investigated in meningiomas of different grades.

ANIMALS

Selected formalin-fixed paraffin-embedded tissue from 43 meningiomas of dogs was evaluated.

METHODS

Genetic material was obtained from pathologic samples and used for quantitative reverse transcriptase real-time polymerase chain reaction (RT-qPCR).

RESULTS

MMP-9 was not expressed in all of the tumors, but MMP-2 was significantly more expressed in papillary meningioma. Likewise, the MMP-2/TIMP-2 ratio was numerically higher in papillary meningiomas compared to all grades (>3.5 times) showing a strong bias in favor of metalloproteinase. In the papillary meningioma, TIMP-1 gene expression was significantly higher than in grades I and III.

CONCLUSIONS AND CLINICAL IMPORTANCE

MMP-2/TIMP-2 imbalance might contribute to the aggressive biologic behavior of papillary meningiomas in dogs. TIMP-1 expression may play a role independent of MMP-9 expression in neoplastic progression. These results further support that therapeutic and prognostic evaluations of dogs with meningioma need to be addressed according to different histologic patterns as is performed in humans.

Feline Injection-Site Sarcoma

Feline injection-site sarcoma (FISS) is an aggressive tumor believed to arise from the proliferation of fibroblasts and myofibroblasts in areas of chronic inflammation, particularly at sites of injection. Local recurrence is frequent after surgical excision. Gelatinases (MMP-2 and MMP-9) and their inhibitor (TIMP-2) are endopeptidases pivotal in extracellular matrix remodeling and therefore in tumor invasiveness. The aim of this study was to investigate the immunohistochemical expression of MMP-2, MMP-9, and TIMP-2 in FISS to assess their usefulness as prognostic factors. Size, soft tissue sarcoma (STS) grading system, depth of infiltration, surgical margins, and Ki-67 index were evaluated as additional prognostic markers. Twenty-four cases of primary FISS were classified according to clinical follow-up as nonrecurrent (NR, n = 14; 58.3%) and recurrent (R, n = 10; 41.7%). MMP-2, MMP-9, and TIMP-2 were variably expressed in the FISS examined, confirming their role in tumor invasiveness, yet they did not show significant differences between the R and NR groups. These results could be due to different tumor stages or to the multiple activities of these enzymes, not limited to ECM remodeling. The immunohistochemical expression of these enzymes considered alone does not seem to be useful as a prognostic marker. STS grading system, depth of infiltration, surgical margins, and Ki-67 index did not relate to recurrence. Instead, the size of the tumor, measured after formalin fixation, with an optimal cutoff of 3.75 cm (accuracy = 86%; P < .05), and the mitotic count, with an optimal cutoff of 20 mitoses/10 HPF (accuracy = 80%; P < .05), could be evaluated as useful prognostic markers.

E-cadherin, N-cadherin Expression and Histologic Characterization of Canine Choroid Plexus Tumors

Choroid plexus tumors (CPTs) are reported with an increasing incidence in dogs, and they call for a reexamination of histologic features and criteria of classification corresponding to their biological behavior. In this study, the human World Health Organization classification was applied to 16 canine CPTs, and the expression of molecules involved in neoplastic cell adhesion (E-cadherin, N-cadherin), invasion (doublecortin), and proliferation (Ki-67) was investigated. Mitotic index was found to be the main criterion for grading CPTs. Cell density and multilayering of papillae were also statistically associated with histologic grade. Intraventricular spread and parenchymal invasion was observed for tumors showing histologic benign features. E-cadherin was expressed in all CPT grades, independent of tumor invasion. N-cadherin immunolabeling was more expressed in grade I than high-grade CPTs, whereas doublecortin expression was not detected in CPTs. An increasing proliferative activity was observed in relation with histologic grade.

Extradural spinal cord lesion in a dog: first case study of canine neurological histoplasmosis in Italy

A 7-year-old intact male mixed dog was presented with a history of acute and progressive paraparesis. Abnormal clinical signs consisted of non-ambulatory paraparesis, hind limbs hypertonia and severe thoracolumbar pain. Magnetic resonance imaging demonstrated an isointense in T1 and T2 WI epidural lesion, with good contrast enhancement, extending from T-10 to T-13. Laminectomy was carried out to remove the epidural mass. Histological examination revealed a pyogranulomatous lesion characterized by numerous macrophages containing yeast-like Grocott and PAS-positive bodies. Immunohistochemistry and PCR performed on formalin-fixed paraffin-embedded tissue confirmed Histoplasma capsulatum as the causative agent. H. capsulatum has a worldwide distribution in temperate and subtropical climates but its presence as an autochthonous fungus in Europe is now recognized. To the authors' knowledge this is the first report of canine histoplasmosis in Italy with lesion confined to the central nervous system.

Refinement of the chromosome 5p locus for familial calcium pyrophosphate dihydrate deposition disease

Familial calcium pyrophosphate dihydrate deposition disease (CPPDD) is a disease of articular cartilage that is radiographically characterized by chondrocalcinosis due to the deposition of calcium-containing crystals in affected joints. We have documented the disease in an Argentinean kindred of northern Italian ancestry and in a French kindred from the Alsace region. Both families presented with a common phenotype including early age at onset and deposition of crystals of calcium pyrophosphate dihydrate in a similar pattern of affected joints. Affected family members were karyotypically normal. Linkage to the short arm of chromosome 5 was observed, consistent with a previous report of linkage of the CPPDD phenotype in a large British kindred to the 5p15 region. However, recombinants in the Argentinean kindred have enabled us to designate a region<1 cM in length between the markers D5S416 and D5S2114 as the CPPDD locus.

Clinical assessment of the 1987 American College of Rheumatology criteria for rheumatoid arthritis

The 1987 American College of Rheumatology (ACR) criteria for the classification of rheumatoid arthritis (RA) were clinically assessed. These criteria do not include findings of synovial fluid (SF) analysis and require no exclusion criteria. We have studied sequential patients with arthritis seen in four rheumatology centers in the Philadelphia area. Classifications by the ACR criteria were compared with our clinical diagnoses. Two hundred ninety eight patients were evaluated, 113 with RA and 185 with other diagnoses. Classifications as RA by the ACR criteria corresponded to our clinical diagnosis in 95% of the cases, corroborating the high sensitivity previously reported. However, we found a lower specificity (73%) than that reported (89%). False positive classifications as RA were found in 71% of patients with psoriatic arthritis, 48% of patients with SLE, and 31% of patients with gout. The specificity could be improved to 89% by excluding disorders with obvious distinguishing extraarticular features such as psoriasis or by SF findings of monosodium urate crystals. Awareness of these possible sources of confusion will further increase the teaching and epidemiologic value of these useful simplified criteria.

Spondyloepiphyseal dysplasia and precocious osteoarthritis in a family with an Arg75-->Cys mutation in the procollagen type II gene (COL2A1)

Direct sequencing of polymerase chain reaction (PCR)-amplified genomic DNA from a patient with spondyloepiphyseal dysplasia and precocious osteoarthritis revealed a single-base change in exon 11 of the type II procollagen gene (COL2A1), which produces an Arg-->Cys mutation in one allele. The proband is a member of a large Chilean kindred presenting with chondrodysplasia of the hips, knees, shoulders, elbows, and spine associated with severe, early-onset osteoarthritis. All affected individuals exhibit mildly short stature; in addition, five out of seven affected family members display shortened metacarpals or metatarsals. DNA from affected and unaffected family members was PCR-amplified and analysis of restriction digests of the products determined that the mutation segregated with the disease with a lod score of 2.2 at zero recombination. The mutation, which resides in the triple-helical region of type II procollagen at amino acid position 75, is the second example of an Arg-->Cys mutation in the COL2A1 gene in heritable cartilaginous disease and is the first example of a point mutation in the amino terminal region of the alpha 1(II) chain, that results in a spondyloepiphyseal dysplastic phenotype.

Pentose phosphate shunt metabolism by cells of the chick growth cartilage

We have measured the activity of the pentose shunt pathway in the chick growth cartilage. Measurement of D-[1-14C] glucose and D-[6-14C] glucose metabolism by chondrocytes indicated that pentose phosphate shunt activity was low. However, when the cells were stimulated with phenazine methosulfate (PMS) and t-butyl hydroperoxide, a significant elevation in shunt activity was observed. This activity was further increased by dithiothreitol. Enzymatic and substrate requirements of the shunt pathway were examined and related to morphology of the tissue. It was found that as chondrocytes mature, there is increased glucose-6-phosphate dehydrogenase activity, and decreased quantities of glucose-6-phosphate and NADPH. While these investigations indicated that shunt activity was maximum in hypertrophic cartilage, the results of cytochemical studies suggested that the activity was greatest in those cells that were most removed from the O2 supply. Experiments were performed to examine O2 requirements of chondrocytes in relationship to the pentose phosphate shunt. First, using a phosphorescence quenching technique, total O2 uptake by these cells was found to be constant over a large part of the physiological range of O2 tensions. Over the same range, when stimulated by PMS, O2 uptake by CN- treated cells was increased. In the 1-5 microM O2 range, non-mitochondrial O2 consumption decreased more slowly than total respiration. Finally, the observation that NADPH directly stimulated chondrocyte O2 consumption suggest that cartilage cells may be able to form O2 metabolites.

Inflammation after blood injection into a synovial-like space is a result of the cellular component rather than the plasma

The rat subcutaneous air pouch, a model for a synovial-like space, has been used to study the effect of blood as an inducer of inflammation. Six-day-old pouches were injected with autologous whole blood, with plasma or with blood cell pellets. We found significantly more inflammation and proliferation of pouch lining in pouches injected with whole blood or with the blood cell pellets than with the plasma. After the injection of blood or the cell component, large numbers of hemoglobin crystals and lipid droplets were found in the pouch fluid and were associated with erosions of the pouch membrane.

Crystal-induced arthritis

The identification of monosodium urate crystals in joint effusions of patients with gouty arthritis established that crystals can cause arthritis. Other crystals causing arthritis have also been identified, including calcium, pyrophosphate dihydrate (chondrocalcinosis, pseudo-gout), calcium hydroxapatite crystals (calcific periarthritis, acute arthritis) and depot corticosteroid crystals (which occasionally cause arthritis when injected intra-articularly.) Crystal-induced arthritis is characterized by acute articular inflammation although rarely causing joint destruction or permanent disability. It is important for clinicians because it can mimic more serious joint diseases like septic arthritis or even rheumatoid arthritis. It can be diagnosed with precision and in some types as in gout can be treated effectively. Also, it constitutes one of the best understood articular inflammatory processes and often is the first clinical clue for the presence of curable metabolic or endocrine diseases.

Giant cell tumour associated with rheumatoid arthritis

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