Preoperative and intraoperative factors predictive of complications and stricture recurrence following multiple urethroplasty techniques.

Objectives: To investigate factors predictive of postoperative recurrence and complications in patients undergoing urethroplasty for stricture repair at a single center. Patients and methods: We retrospectively reviewed the records of 108 men who underwent urethroplasty for urethral stricture disease (USD) at a single center from 2016 to 2020. Demographic data, comorbidities, stricture history including etiology and prior treatments, patient-reported symptoms, and outcomes data were collected for analysis. Data were analyzed in aggregate, then, stratified by type of urethroplasty performed. Descriptive statistics, univariate analysis, multivariate logistic regression, and intergroup comparisons were completed using STATA, with an alpha value of 0.05 and a confidence interval of 95%. Results: The median age of our patients was 58 years (interquartile range: 42-69; range: 29-83), with a median stricture length of 2.0 cm (interquartile range: 1.0-4.5; range: 0.5-10). The most common stricture etiology was iatrogenic (n = 33, 31%) and the most common urethroplasty was anterior anastomotic urethroplasty (n = 38, 35%), followed by buccal mucosal graft (BMG) urethroplasty (n = 35, 32%). Twenty-four patients (22%) had stricture recurrence. Within the aggregate data, recurrence was significantly predicted by obesity (BMI > 30) (Odds Ratio [OR] 3.2, 95% Confidence Interval [CI]: 1.06-10), and the presence of postoperative complications (OR 6.3, CI: 1.9-21). The presence of any postoperative complications within 90 days was significantly predicted by stricture length ≥ 5 cm (OR 3.5, CI 1.09-12) and recurrence (OR 6.0, CI 1.7-21). Conclusion: Despite serving as the most definitive treatment for urethral stricture management, stricture recurrence and postoperative complications are not uncommon after urethroplasty. Obesity and stricture length negatively impact outcomes while a penile stricture location is associated with a lower recurrence rate, though this is not statistically significant.

Preoperative anaemia and clinical outcomes in the South African Surgical Outcomes Study.

BACKGROUND: In high-income countries, preoperative anaemia has been associated with poor postoperative outcomes. To date, no large study has investigated this association in South Africa (SA). The demographics of SA surgical patients differ from those of surgical patients in the European and Northern American settings from which the preoperative anaemia data were derived. These associations between preoperative anaemia and postoperative outcomes are therefore not necessarily transferable to SA surgical patients. OBJECTIVES: The primary objective was to determine the association between preoperative anaemia and in-hospital mortality in SA adult non-cardiac, non-obstetric patients. The secondary objectives were to describe the association between preoperative anaemia and (i) critical care admission and (ii) length of hospital stay, and the prevalence of preoperative anaemia in adult SA surgical patients. METHODS: We performed a secondary analysis of the South African Surgical Outcomes Study (SASOS), a large prospective observational study of patients undergoing inpatient non-cardiac, non-obstetric surgery at 50 hospitals across SA over a 1-week period. To determine whether preoperative anaemia is independently associated with mortality or admission to critical care following surgery, we conducted a multivariate logistic regression analysis that included all the independent predictors of mortality and admission to critical care identified in the original SASOS model. RESULTS: The prevalence of preoperative anaemia was 1 727/3 610 (47.8%). Preoperative anaemia was independently associated with in-hospital mortality (odds ratio (OR) 1.657, 95% confidence interval (CI) 1.055 - 2.602; p=0.028) and admission to critical care (OR 1.487, 95% CI 1.081 - 2.046; p=0.015). CONCLUSIONS: Almost 50% of patients undergoing surgery at government-funded hospitals in SA had preoperative anaemia, which was independently associated with postoperative mortality and critical care admission. These numbers indicate a significant perioperative risk, with a clear need for quality improvement programmes that may improve surgical outcomes. Long waiting lists for elective surgery allow time for assessment and correction of anaemia preoperatively. With a high proportion of patients presenting for urgent or emergency surgery, perioperative clinicians in all specialties should educate themselves in the principles of patient blood management.

Preoperative anaemia and clinical outcomes in the South African surgical outcomes study

Background.In high-income countries, preoperative anaemia has been associated with poor postoperative outcomes. To date, no large study has investigated this association in South Africa (SA). The demographics of SA surgical patients differ from those of surgical patients in the European and Northern American settings from which the preoperative anaemia data were derived. These associations between preoperative anaemia and postoperative outcomes are therefore not necessarily transferable to SA surgical patients.Objectives. The primary objective was to determine the association between preoperative anaemia and in-hospital mortality in SA adult non-cardiac, non-obstetric patients. The secondary objectives were to describe the association between preoperative anaemia and (i) critical care admission and (ii) length of hospital stay, and the prevalence of preoperative anaemia in adult SA surgical patients.Methods. We performed a secondary analysis of the South African Surgical Outcomes Study (SASOS), a large prospective observational study of patients undergoing inpatient non-cardiac, non-obstetric surgery at 50 hospitals across SA over a 1-week period. To determine whether preoperative anaemia is independently associated with mortality or admission to critical care following surgery, we conducted a multivariate logistic regression analysis that included all the independent predictors of mortality and admission to critical care identified in the original SASOS model.Results. The prevalence of preoperative anaemia was 1 727/3 610 (47.8%). Preoperative anaemia was independently associated with in-hospital mortality (odds ratio (OR) 1.657, 95% confidence interval (CI) 1.055 - 2.602; p=0.028) and admission to critical care (OR 1.487, 95% CI 1.081 - 2.046; p=0.015).Conclusions. Almost 50% of patients undergoing surgery at government-funded hospitals in SA had preoperative anaemia, which was independently associated with postoperative mortality and critical care admission. These numbers indicate a significant perioperative risk, with a clear need for quality improvement programmes that may improve surgical outcomes. Long waiting lists for elective surgery allow time for assessment and correction of anaemia preoperatively. With a high proportion of patients presenting for urgent or emergency surgery, perioperative clinicians in all specialties should educate themselves in the principles of patient blood management

TBX6 null variants and a common hypomorphic allele in congenital scoliosis.

BACKGROUND: Congenital scoliosis is a common type of vertebral malformation. Genetic susceptibility has been implicated in congenital scoliosis. METHODS: We evaluated 161 Han Chinese persons with sporadic congenital scoliosis, 166 Han Chinese controls, and 2 pedigrees, family members of which had a 16p11.2 deletion, using comparative genomic hybridization, quantitative polymerase-chain-reaction analysis, and DNA sequencing. We carried out tests of replication using an additional series of 76 Han Chinese persons with congenital scoliosis and a multicenter series of 42 persons with 16p11.2 deletions. RESULTS: We identified a total of 17 heterozygous TBX6 null mutations in the 161 persons with sporadic congenital scoliosis (11%); we did not observe any null mutations in TBX6 in 166 controls (P<3.8×10(-6)). These null alleles include copy-number variants (12 instances of a 16p11.2 deletion affecting TBX6) and single-nucleotide variants (1 nonsense and 4 frame-shift mutations). However, the discordant intrafamilial phenotypes of 16p11.2 deletion carriers suggest that heterozygous TBX6 null mutation is insufficient to cause congenital scoliosis. We went on to identify a common TBX6 haplotype as the second risk allele in all 17 carriers of TBX6 null mutations (P<1.1×10(-6)). Replication studies involving additional persons with congenital scoliosis who carried a deletion affecting TBX6 confirmed this compound inheritance model. In vitro functional assays suggested that the risk haplotype is a hypomorphic allele. Hemivertebrae are characteristic of TBX6-associated congenital scoliosis. CONCLUSIONS: Compound inheritance of a rare null mutation and a hypomorphic allele of TBX6 accounted for up to 11% of congenital scoliosis cases in the series that we analyzed. (Funded by the National Basic Research Program of China and others.).

Risk of port-site metastases in pelvic cancers after robotic surgery.

OBJECTIVE: To assess the risk of occurrence of port-site metastases after robotic surgery for pelvic cancer. METHODS: Retrospective study from June 2007 to March 2013 of patients with gynecologic cancer who underwent robot-assisted surgery. We collected preoperative data, including characteristics of patients and FIGO stage, intraoperative data (surgery performed, number of ports), and postoperative data (occurrence of metastases, occurrence of port-site metastases). RESULTS: 115 patients were included in the study: 61 with endometrial cancer, 50 with cervical cancer and 4 with ovarian cancer. The surgical procedures performed were: hysterectomy with bilateral salpingo-oophorectomy, radical hysterectomy, pelvic lymphadenectomy, para-aortic lymphadenectomy and omentectomy. All surgical procedures required the introduction of 4 ports, 3 for the robot and 1 for the assistant. With a mean follow-up of 504.4 days (507.7 days for endometrial cancer, 479.5 days for cervical cancer, and 511.3 for ovarian cancer), we observed 9 recurrences but no port-site metastasis. CONCLUSION: No port-site metastasis has occurred in our series. However, larger, prospective and randomized works are needed to formally conclude.

MRI characteristics of globus pallidus infarcts in isolated methylmalonic acidemia.

BACKGROUND: Bilateral infarcts confined to the globus pallidus are unusual and occur in conjunction with only a few disorders, including isolated methylmalonic acidemia, a heterogeneous inborn error of metabolism. On the basis of neuroradiographic features of metabolic strokes observed in a large cohort of patients with methylmalonic acidemia, we have devised a staging system for methylmalonic acidemia-related globus pallidus infarcts. MATERIALS AND METHODS: Forty patients with isolated methylmalonic acidemia and neurologic symptoms underwent clinical brain MR imaging studies, which included 3D-T1WI. Infarcted globus pallidus segments were neuroanatomically characterized, and infarct volumes were measured. RESULTS: Globus pallidus infarcts were present in 19 patients; all were bilateral, and most were left-dominant. A neuroanatomic scoring system based on the infarct patterns was devised; this revealed a 5-stage hierarchical susceptibility to metabolic infarct, with the posterior portion of the globus pallidus externa being the most vulnerable. Globus pallidus infarct prevalence by methylmalonic acidemia class was the following: cblA (5/7, 71%), cblB (3/7, 43%), mut(o) (10/22, 45%), and mut- (1/4, 25%). Tiny lacunar infarcts in the pars reticulata of the substantia nigra, previously unrecognized in methylmalonic acidemia, were found in 17 patients, 13 of whom also had a globus pallidus infarct. CONCLUSIONS: The staged pattern of globus pallidus infarcts in isolated methylmalonic acidemia suggests a nonuniform, regionally specific cellular susceptibility to metabolic injury, even for patients having milder biochemical phenotypes. In support of this hypothesis, the delineation of lacunar infarcts in the pars reticulata of the substantia nigra, a tissue functionally and histologically identical to the globus pallidus interna, supports the concept of cell-specific pathology.

[Polypharmacy is an indicator for a poor prognosis, which is not altered by deprescribing in nursing home]. / Polypharmazie ist ein Indikator für kurze Überlebensdauer im Pflegeheim - Daran ändert das Absetzen von Medikamenten nichts.

AIM: To examine the influence of polypharmacy ordered by the pretreating site and deprescribing (i.e. the appropriate withdrawal of prescribed drugs) by the nursing home physician on survival time. METHODS: Retrospective Analysis of medical databasis from 1,249 patients, thereof 611 in a nursing home with practice of deprescribing. RESULTS: 70% of the patients with excessive polypharmacy (>9 drugs), 57% of those with polypharmacy (6 to 9 drugs) and 43% of the remaining patients (<6 drugs) deceased within 286 days after admission (chi-squared 2 DF = 43.72; p <0.001). Deprescribing by the nursing home physician at admission revealed no influence on survival time. CONCLUSION: Polypharmacy is not the reason, but an indicator for a poor prognosis, which is not altered by deprescribing.

Adipocyte fatty acid-binding protein as a novel prognostic factor in obese breast cancer patients.

Several adipocytokines, such as leptin or adiponectin, are associated with obesity and the risk for breast cancer. Adiopcyte fatty acid binding-protein(A-FABP) is another protein found in adipose tissue;therefore, we investigated the association of A-FABP with the occurrence and prognosis of breast cancer. In our study,200 women attending the University of Ulm for breast surgery between the years 2005 and 2007 were included;159 had histologically confirmed breast cancer; 41 had histologically confirmed benign lesions. Serum levels ofA-FABP, leptin, and adiponectin were measured, and their relationship to body-mass-index (BMI), breast cancer, and tumor characteristics were analyzed; logistic regression model was adjusted to age, BMI, menopausal status, use of Hormone Replacement Therapy (HRT), and family history of breast cancer. Serum A-FABP levels were found to be significantly higher in obese (BMI C 25) than in non-obese women (BMI B 24.9), 41.16 ng/ml and 24.95 ng/ml,respectively (P\0.0001). Independent of obesity, the serum A-FABP levels were significantly higher in breast cancer patients (34.65 ng/ml) than in healthy controls(24.47 ng/ml), P\0.0001; the odds ratio (1.038, P\0.05,95% confidence interval 1.001-1.72) showed a significant association of A-FABP with breast cancer risk. Serum leptin levels showed a strong correlation with BMI(rs = 0.78) and were significantly higher in breast cancer patients (20.87 ng/ml) than in controls (14.90 ng/ml),P\0.05. In contrast, adiponectin showed no significant association with breast cancer. Concerning tumor characteristics,A-FABP was positively connected with tumor size (T C 2 cm, P\0.05) and nodal-status (P\0.05).Our study reveals that high A-FABP serum levels are associated with obesity, breast cancer risk, and adverse tumor characteristics.

Hyperlipidemia resulting in abnormal density and signal intensity of blood in a neonate with lipoprotein lipase deficiency.

We present the imaging findings in an 8-week-old infant with LPL deficiency. Due to markedly increased lipoproteins in the serum, abnormal hypodensity and abnormal T1-weighted hyperintensity were identified in the dural venous sinuses and medullary veins.

Genome-wide analysis of the yeast transcriptome upon heat and cold shock.

DNA arrays were used to measure changes in transcript levels as yeast cells responded to temperature shocks. The number of genes upregulated by temperature shifts from 30 to 37 or 45 was correlated with the severity of the stress. Pre-adaptation of cells, by growth at 37 previous to the 45 shift, caused a decrease in the number of genes related to this response. Heat shock also caused downregulation of a set of genes related to metabolism, cell growth and division, transcription, ribosomal proteins, protein synthesis and destination. Probably all of these responses combine to slow down cell growth and division during heat shock, thus saving energy for cell rescue. The presence of putative binding sites for Xbp1p in the promoters of these genes suggests a hypothetical role for this transcriptional repressor, although other mechanisms may be considered. The response to cold shock (4) affected a small number of genes, but the vast majority of those genes induced by exposure to 4 were also induced during heat shock; these genes share in their promoters cis-regulatory elements previously related to other stress responses.

Genome-wide analysis of yeast transcription upon calcium shortage.

Several regulatory circuits related to important functions, like membrane excitation, immunoresponse, replication, control of the cell cycle and differentiation, among others, cause an increase in intracellular calcium level that finally has a consequence upon transcription of specific genes. The sequencing of the whole genome of eukaryotic cells enables genome-wide analysis of gene expression under many conditions not yet assessed by conventional methods. Using the array technology, the effect of calcium shortage in yeast cells was studied. Correspondence analysis of data showed that there is a response in transcription that is correlated to calcium shortage. The distribution of up-regulated-genes in functional categories suggests a regulatory connection between the cell-cycle progression and the energetic metabolic requirements for growth and division. In silico analysis of promoters reveals the frequent appearance of the Mlu I cell cycle box (MCB) cis element that binds the transcriptional regulatory factor Mcm1.

Correspondence analysis applied to microarray data.

Correspondence analysis is an explorative computational method for the study of associations between variables. Much like principal component analysis, it displays a low-dimensional projection of the data, e.g., into a plane. It does this, though, for two variables simultaneously, thus revealing associations between them. Here, we demonstrate the applicability of correspondence analysis to and high value for the analysis of microarray data, displaying associations between genes and experiments. To introduce the method, we show its application to the well-known Saccharomyces cerevisiae cell-cycle synchronization data by Spellman et al. [Spellman, P. T., Sherlock, G., Zhang, M. Q., Iyer, V. R., Anders, K., Eisen, M. B., Brown, P. O., Botstein, D. & Futcher, B. (1998) Mol. Biol. Cell 9, 3273-3297], allowing for comparison with their visualization of this data set. Furthermore, we apply correspondence analysis to a non-time-series data set of our own, thus supporting its general applicability to microarray data of different complexity, underlying structure, and experimental strategy (both two-channel fluorescence-tag and radioactive labeling).

Whole genome analysis of a wine yeast strain.

Saccharomyces cerevisiae strains frequently exhibit rather specific phenotypic features needed for adaptation to a special environment. Wine yeast strains are able to ferment musts, for example, while other industrial or laboratory strains fail to do so. The genetic differences that characterize wine yeast strains are poorly understood, however. As a first search of genetic differences between wine and laboratory strains, we performed DNA-array analyses on the typical wine yeast strain T73 and the standard laboratory background in S288c. Our analysis shows that even under normal conditions, logarithmic growth in YPD medium, the two strains have expression patterns that differ significantly in more than 40 genes. Subsequent studies indicated that these differences correlate with small changes in promoter regions or variations in gene copy number. Blotting copy numbers vs. transcript levels produced patterns, which were specific for the individual strains and could be used for a characterization of unknown samples.

Competency assessment and proficiency testing.

Competency assessment is an ongoing, continuous process of monitoring individuals' abilities to perform their specific job functions. A variety of methods are useful in monitoring cytology competency, including rescreening studies, descriptive monitors (abnormality rates), discrepancy rates, workload patterns, competency-based educational programs and programs using unknown slide challenges. The goal of proficiency testing (PT) is to ascertain and assess the ability of individuals beyond the particular items or challenges presented. However, cytology PT faces many challenges for implementation as it cannot duplicate normal working conditions, and there is often no gold standard to define the truth. PT is just one measure of performance and should be considered in conjunction with other quality assessment monitors. There is no consensus on the value or validity of a large-scale regulatory PT program. Any regulatory PT program should be field tested prior to implementation, and the grading system should be scientifically defensible. Scoring of performance on PT should occur in a timely fashion, and there should be an opportunity for educational feedback. The ultimate aim of both competency assessment and PT is to positively affect laboratory procedures and improve the cervical cancer screening process.

Processing and quality control of DNA array hybridization data.

MOTIVATION: The technology of hybridization to DNA arrays is used to obtain the expression levels of many different genes simultaneously. It enables searching for genes that are expressed specifically under certain conditions. However, the technology produces large amounts of data demanding computational methods for their analysis. It is necessary to find ways to compare data from different experiments and to consider the quality and reproducibility of the data. RESULTS: Data analyzed in this paper have been generated by hybridization of radioactively labeled targets to DNA arrays spotted on nylon membranes. We introduce methods to compare the intensity values of several hybridization experiments. This is essential to find differentially expressed genes or to do pattern analysis. We also discuss possibilities for quality control of the acquired data. AVAILABILITY: http://www.dkfz.de/tbi CONTACT: M.Vingron@dkfz-heidelberg.de

Normal skeletal development of mice lacking matrilin 1: redundant function of matrilins in cartilage?

Matrilin 1, or cartilage matrix protein, is a member of a novel family of extracellular matrix proteins. To date, four members of the family have been identified, but their biological role is unknown. Matrilin 1 and matrilin 3 are expressed in cartilage, while matrilin 2 and matrilin 4 are present in many tissues. Here we describe the generation and analysis of mice carrying a null mutation in the Crtm gene encoding matrilin 1. Anatomical and histological studies demonstrated normal development of homozygous mutant mice. Northern blot and biochemical analyses show no compensatory up-regulation of matrilin 2 or 3 in the cartilage of knockout mice. Although matrilin 1 interacts with the collagen II and aggrecan networks of cartilage, suggesting that it may play a role in cartilage tissue organization, studies of collagen extractability indicated that collagen fibril maturation and covalent cross-linking were unaffected by the absence of matrilin 1. Ultrastructural analysis did not reveal any abnormalities of matrix organization. These data suggest that matrilin 1 is not critically required for cartilage structure and function and that matrilin 1 and matrilin 3 may have functionally redundant roles.

[Cartilage oligomeric matrix protein (COMP): the role of a non-collagen cartilage matrix protein as a marker of disease activity and joint destruction in patients with rheumatoid arthritis and osteoarthritis]. / Cartilage Oligomeric Matrix Protein (COMP): Die Rolle eines nichtkollagenen Knorpel-Matrix-Proteins als Marker der Krankheitsaktivität und Gelenkzerstörung bei Patienten mit rheumatoider Arthritis und Arthrose.

UNLABELLED: Today, we can assess criteria to predict the tissue destruction and progression of Rheumatoid Arthritis (RA) and Osteoarthritis (OA) only in a late stage of the disease. It would be an advantage to have biochemical markers of disease activity and joint destruction to optimize therapy. PATIENTS AND METHODS: In this cross-sectional study with 37 RA and 20 OA patients (disease duration 119 +/- 130 months for RA and 41 +/- 73 months for OA), ESR, CRP, disease activity score (DAS), the functional status of RA (American College of Rheumatology), and the radiological scoring systems of Larsen and Kellgren/Lawrence, respectively, were used as parameters for disease activity and joint destruction. Cartilage oligomeric matrix protein (COMP) was measured with an enzyme-linked immunosorbent assay (ELISA) in serum and synovial fluid, COMP fragments with immunoblot in the synovial fluid. RESULTS: The mean COMP value in synovial fluid was 38 ug/ml (RA) and 46 ug/ml (OA); 6.5 ug/ml (RA) and 3.4 ug/ml (OA) in serum. RA patients had a higher amount of small COMP fragments in synovial fluid than OA patients. In RA patients, there was a significant positive correlation between disease activity (DAS) and COMP in synovial fluid and serum, a negative correlation between functional status of RA and serum COMP and between radiologic joint destruction of the knee and serum COMP. In OA patients, there was a significant correlation of joint space width and synovial fluid COMP. DISCUSSION: A high clinical disease activity (DAS) correlated with high COMP values in serum and synovial fluid and with increasing proteolytic activity (higher amount of small COMP fragments especially in RA). An increased turnover of cartilage matrix in joint inflammation might explain this correlation. The correlation of decreased COMP with decreased functional status in RA and increased joint destruction is compatible with a loss of cartilage and less turnover. The correlation between joint space width and increased COMP in OA patients with short disease duration might be explained with a higher turnover of the cartilage matrix in the early stage of the disease.

Matrilin-2, a large, oligomeric matrix protein, is expressed by a great variety of cells and forms fibrillar networks.

Matrilin-2 is a member of the protein superfamily with von Willebrand factor type A-like modules. Mouse matrilin-2 cDNA fragments were expressed in 293-EBNA cells, and the protein was purified, characterized, and used to immunize rabbits. The affinity-purified antiserum detects matrilin-2 in dense and loose connective tissue structures, subepithelial connective tissue of the skin and digestive tract, specialized cartilages, and blood vessel walls. In situ hybridization of 35S-labeled riboprobes localizes the matrilin-2 mRNA to fibroblasts of dermis, tendon, ligaments, perichondrium, and periosteum; connective tissue elements in the heart; smooth muscle cells; and epithelia and loose connective tissue cells of the alimentary canal and respiratory tract. RNA blot hybridization and immunoblotting revealed both matrilin-2 mRNA and protein in cultures of a variety of cell types, confirming the tissue distribution. Alternative splicing affects a module unique for matrilin-2 in all of the above RNA sources. SDS-polyacrylamide gel electrophoresis and electron microscopy reveals matrilin-2 from tissue extracts and cell line cultures as a mixture of mono-, di-, tri-, and tetramers. Matrilin-2 is substituted with N-linked oligosaccharides but not with glycosaminoglycans. Because of other, yet unidentified, cell-type dependent posttranslational modifications, the monomer is heterogeneous in size. Immunofluorescence showed that matrilin-2 functions by forming an extracellular, filamentous network.

Transcriptional profiling on all open reading frames of Saccharomyces cerevisiae.

Open reading frames (6116) of the budding yeast Saccharomyces cerevisiae were PCR-amplified from genomic DNA using 12,232 primers specific to the ends of the coding sequences; the success rate of amplification was 97%. PCR-products were made accessible to hybridization by being arrayed at very high density on solid support media using various robotic devices. Probes made from total RNA preparations were hybridized for the analysis of the transcriptional activity of yeast under various growth conditions and of different strains. Experimental factors that proved critical to the performance, such as different RNA isolation procedures and the assessment of hybridization results, for example, were investigated in detail. Various software tools were developed that permit convenient handling and sound analysis of the large data quantities obtained from transcriptional profiling studies. Comprehensive arrays are being distributed within the European Yeast Functional Analysis Network (EUROFAN) and beyond.

Analysis of cartilage oligomeric matrix protein (COMP) in synovial fibroblasts and synovial fluids.

We investigated the expression of cartilage oligomeric matrix protein (COMP) in normal and rheumatoid arthritis (RA) synovial fibroblasts. In situ hybridization (ISH) was conducted on synovial specimens from five RA patients applying specific probes for COMP or fibroblast collagen type I. ISH was combined with immunohistochemistry, applying antibodies to the macrophage marker CD68. Ribonuclease protection assay (RPA) and rapid amplification of 3'-cDNA ends (3'-RACE) were performed on total RNA from normal and RA synovial fibroblast cultures. Protein extracts from fibroblasts and culture supernatants were compared with synovial fluids and protein extracts from isolated chondrocytes by Western blot utilizing polyclonal and monoclonal antibodies (18-G3 mAb) to COMP. COMP mRNA was detected in fibroblasts of RA synovium by ISH, and in normal and RA synovial fibroblast cultures by RPA. 3'-RACE demonstrated sequence homology of chondrocyte and synovial fibroblast COMP along the coding sequence. COMP protein was detected in synovial fibroblasts and culture supernatants by immunoblot. Using polyclonal antibodies, the major portion of COMP from fibroblasts and culture supernatants was present as low-molecular-weight (LMW) bands, corresponding to those found in synovial fluids. These LMW COMP bands, however, were not detected in any of the cells or tissues tested using 18-G3 mAb. In protein extracts from chondrocytes and in COMP purified from cartilage, these LMW bands could not be detected. In conclusion, the data suggest that certain forms of COMP detected in synovial fluid are secreted from synovial fibroblasts and could be distinguished by specific mAbs from COMP secreted by chondrocytes.