PubMed Health⌕ Search

Biomedical subjects

G Verbruggen

Publications and source records attributed to G Verbruggen.

At least 19 recordsLinked to original sources
PubMed1996

Numerical scoring systems for the anatomic evolution of osteoarthritis of the finger joints.

OBJECTIVE: To assess and score the progression of osteoarthritis (OA) of the distal and proximal interphalangeal (DIP and PIP) and metacarpophalangeal (MCP) joints. METHODS: Forty-six patients with OA of the finger joints were followed up for 3 years; 36 of them were followed up for 5 years. Posteroanterior radiographs of the hands were obtained at the start of this prospective study and at yearly intervals. The scoring systems used were based on the increased incidence of OA during consecutive years in previously normal joints, the radiologic progression of anatomic lesions in the affected finger joints, and the consecutive pathologic phases recognized in the course of the disease. RESULTS: Significant increases both in the numbers of affected DIP, PIP and MCP joints per subject and in the anatomic progression of the disease (changes in osteophyte growth, loss of joint space, and subchondral cysts or sclerosis) in the different finger joints of each patient were recorded during the 3 and 5 years of followup. In approximately 40% of the patients, the classic picture of OA was complicated by erosive changes, which preceded a period in which repair phenomena in the "eroded" finger joints led to the generation of a new subchondral plate covered by cartilaginous tissue. Huge osteophytes were then responsible for the nodular aspect of the affected finger joints. CONCLUSION: OA of the finger joints is progressive in nature and passes through predictable phases. The recognition of and the attribution of a score to these respective phases made assessing the progression of OA less time-consuming and led to the same conclusions as when the anatomic progression was scored.

Arthrography↗
PubMed1996

Human meniscal proteoglycan metabolism in long-term tissue culture.

For the purpose of human meniscal allografting, menisci have been maintained viable in in vitro culture. The influence of long-term tissue culture on the extracellular matrix metabolism of the meniscus has been studied. Fetal calf serum (FCS) was used as a supplement for the growth factors necessary to maintain optimal meniscal cell metabolism. A series of semilunar cartilage samples was cultured under serum-free conditions since foreign proteins could be responsible for immunological problems after eventual allografting. The proteoglycan metabolism in human menisci cultured in FCS-supplemented and in serum-free culture media was compared. To rule out any influence of topographical variations in glycosaminoglycan (GAG) content on proteoglycan (PG) metabolism, GAG concentrations within the tissue were determined, and sulphate (35S) incorporation was studied in tissue samples with a comparable biochemical composition. Sulphate incorporation was preserved when 20% FCS was added to the nutrient medium. The meniscal tissue fibroblasts continued to produce 35S-PG during 4 weeks of culture. The PG molecules were shown to consist of PG-aggregates, monomers and a low molecular-weight PG population. Newly synthesized GAG consisted of approximately 55% chondroitin 4- and 6-sulphate and 33% dermatan sulphate. In the presence of serum, 35S incorporation in PG and in the PG-aggregate fraction significantly increased during the first 2 weeks and then decreased during the following 2 weeks of in vitro culture. Newly synthesized PG-aggregates were almost entirely accumulated in the tissue during these weeks. In the 3rd week the values for this parameter decreased slightly. 35S-PG synthesis dramatically declined after 4 weeks of in vitro culture. Catabolism probably resulted in increased proportions of 35S-PG in the incubation media. In the absence of serum, 35S-PG production also increased in the 2nd week of culture. However, 35S activity was almost exclusively found in small PG, and this material apparently diffused to the incubation media. Consequently, catabolism is higher, and the immobilization of 35S-PG is poor when FCS is not added to the culture media. Our findings suggest that menisci are maintained in viable condition and may serve for allografting at least during 2 weeks of tissue culture.

Adult↗
PubMed1995

Standardization of nutrient media for isolated human articular chondrocytes in gelified agarose suspension culture.

Human articular cartilage cells were cultured in 1.5% agarose in Dulbecco's modified Eagle's medium (DMEM) with 10% fetal calf serum or in serum-free DMEM with 0.15% bovine serum albumin. 35S-aggrecan synthesis in serum-free DMEM was between 20% and 30% of the value observed in DMEM supplemented with 10% fetal calf serum. The extent to which different growth or differentiation factors were able to restore 35S incorporation in aggrecan in serum-free DMEM was determined: human serum transferrin had no effect on aggrecan synthesis levels; bovine pancreas insulin, insulin-like growth factor (IGF)-1 and IGF-2 restored 35S-aggrecan synthesis to 35-50% of the control levels. The effects were dose-dependent, to level off at 100 ng/mL for the three factors. No cumulative or synergistic activities were observed when these factors were combined. Transforming growth factor (TGF)-beta, at concentrations ranging from 10-50 ng/mL stimulated aggrecan synthesis to approximately 50% of the control values in the chondrocytes obtained from two out of four donors, while the cells of the other two maintained within the range of the control levels. In th presence of insulin (100 ng/mL) 10 ng/mL of TGF-beta stimulated aggrecan synthesis to more than 90% of the control level in the chondrocytes of all donors.

Adult↗
PubMed1995

Numerical scoring systems for the progression of osteoarthritis of the finger joints.

We developed methods to assess and to score progression of osteoarthritis (OA) of the distal and proximal interphalangeal (DIP and PIP) and metacarpophalangeal (MCP) finger joints. Thirty-six patients with osteoarthritis (OA) of the finger joints were followed for five years. Anteroposterior radiographs of the hands were obtained at the start of this prospective study and at yearly intervals. The scoring systems used were based on: -1- the increase in incidence of OA during consecutive years in previously normal joints. -2- the radiological progression of the anatomical lesions (changes in osteophyte growth, loss of joint space, subchondral cysts or sclerosis) in pathological finger joints. -3- the consecutive pathological phases recognized in the course of the disease. Significant increases in both the numbers of affected DIP, PIP and MCP joints per subject and the anatomical progression of the disease in the different finger joints of each individual patient were recorded during the 5-year follow-up. In approx. 40% of the patients the classical picture of OA was complicated by manifest erosive changes, which preceded a period in which repair phenomena in the 'eroded' finger joints led to generation of a new subchondral plate covered by cartilaginous tissue. Huge osteophytes were then responsible for the nodular aspect of the affected finger joints. OA of the finger joints in our patients was progressive in nature and went through predictable phases. Recognition and scoring of these phases allowed faster assessment of OA progression and led to the same conclusions as scoring the anatomical progression.

Cartilage, Articular↗
PubMed1994

Coculture of human articular chondrocytes with peripheral blood mononuclear cells as a model to study cytokine-mediated interactions between inflammatory cells and target cells in the rheumatoid joint.

A model for the coculture of chondrocytes in gelified agarose with mononuclear cells was developed to serve as an in vitro equivalent for cytokine-mediated events at the cartilage-synovial pannus junction in destructive arthropathies. Chondrocytes cultured in agarose keep their phenotypic stability. They release cartilage-specific aggrecans into the surrounding artificial matrix. When activated with lipopolysaccharide for 1 h, mononuclear cells release Interleukin 1 beta and Tumor Necrosis Factor alpha, thereby stimulating the chondrocytes to produce Interleukin 6, to diminish incorporation of 35S into aggrecans, and to degrade these intercellular macromolecules. This coculture model is a useful tool for studying interactions between inflammatory cells and target cells. To demonstrate its usefulness, the effect of three anti-inflammatory drugs (piroxicam, sulphasalazine, and hydrocortisone) on cytokine release by mononuclear cells, and subsequently on chondrocyte aggrecan metabolism was studied. The drugs were unable to abrogate Interleukin 1 and Tumor Necrosis Factor alpha release by activated mononuclear cells. Therefore, these pharmacological agents did not protect the artificial target tissue against cytokine-mediated degradation.

Adult↗
PubMed1994

Comparative and combined effects of interleukin 6, interleukin 1 beta, and tumor necrosis factor alpha on proteoglycan metabolism of human articular chondrocytes cultured in agarose.

OBJECTIVE: To study the effects of recombinant tumor necrosis factor alpha (TNF-alpha), interleukin 1 beta (IL-1 beta) and interleukin 6 (IL-6) on proteoglycan metabolism of isolated chondrocytes. METHODS: Human articular cartilage cells were cultured in agarose gel. In these culture conditions, chondrocytes keep their phenotypic stability. They release cartilage specific proteoglycans into the surrounding artificial matrix. Proteoglycan synthesis was measured by the incorporation of 35sulfate (35S). RESULTS: TNF-alpha and IL-1 beta depressed proteoglycan synthesis and induced proteoglycan degradation. The effects of both cytokines were additive, when used in submaximal doses. No mutual induction of TNF-alpha and IL-1 beta was shown, but both cytokines stimulated the chondrocytes to release IL-6, up to 100,000 pg/ml. Equal amounts of human recombinant IL-6 did not affect proteoglycan synthesis. IL-6 did not alter proteoglycan quality, nor did it modulate the IL-1 beta activities on proteoglycan metabolism. CONCLUSION: These findings illustrate the role of IL-1 beta and TNF-alpha in cartilage degradation and suggest that the role of the large amounts of IL-6 released in response to IL-1 in chronic arthritis is not directly protective with regard to proteoglycan metabolism.

Arthritis↗
PubMed1994

[Viable meniscus transplantation].

The integrity of the semilunar cartilages has proved to be the best safeguard against mechanical degenerative changes. One can postulate that restoring normal congruency between the femur and tibia with intact menisci would be the ideal solution to many mechanical knee problems. Several semilunar cartilages have been transplanted with good functional results in medial and lateral compartmental meniscal disease. However, this form of chondroprotection in the load-bearing area of the femur and tibia can only be properly evaluated after 10 to 20 years of follow-up. In order to obtain functional results, meniscal allografts have to be incorporated in the knee joint by intimate meniscofemoral synovial bonding. The synovial fibroblasts must grow into the collagen meshwork of the meniscal allograft. Such ingrowth has been shown in freeze-dried and deep-frozen meniscal allografts. However, in a small number of transplants shrinking has been observed on repeat arthroscopy at 6 months. Satisfactory incorporation of meniscal allografts has been obtained with fresh allografts, but availability remains a problem when this method is used for meniscal substitution. For this reason viable meniscal allograft implantation was initiated in a series of 25 patients and the value of this method studied. The meniscal allograft can be kept in an adequate semisynthetic nutrient medium for approximately 2-3 weeks without apparent loss of viability, during which period the appropriate recipient can be selected and prepared, a thorough laboratory screening can be conducted, and the culture results and disease transmission factors can be evaluated. In this way, live transplant hazards can be avoided, resulting in a higher success rate.

Adult↗
PubMed1993

T cell receptor V beta usage in rheumatoid nodules: marked oligoclonality among IL-2 expanded lymphocytes.

Rheumatoid arthritis is an autoimmune disease which is characterized by chronic polyarthritis and joint destruction as well as by extra-articular manifestations, typically including the appearance of rheumatoid nodules. Although the pathogenesis of the disease is unknown, substantial evidence suggests that it is T cell-mediated. In contrast to experimental models, the disease-mediating T cells in the human situation have never been isolated or identified. We expanded T lymphocytes from human rheumatoid nodules by IL-2 stimulation and observed a marked oligoclonality among these expanded lymphocytes. This tendency towards oligoclonality was not seen in IL-2-expanded lymphocytes from peripheral blood. We hypothesize that this oligoclonal expansion reflects a clonally restricted in situ preactivation of lymphocytes and that precisely these preactivated cells are involved in the pathogenesis of the rheumatic process.

Aged↗
PubMed1993

Development of immortalized human articular cartilage cell lines.

Human articular cartilage cells were transfected with the t.-sensitive polyomavirus large T antigen of SV40. Several immortalized chondrocyte cell lines were obtained. The types of acidic polysaccharides and of collagen synthesized suggest dedifferentiation in the in vitro culture system used afterwards to obtain large numbers of cells.

Antigens, Polyomavirus Transforming↗
PubMed1993

Influence of interferon-gamma on isolated chondrocytes from human articular cartilage. Dose dependent inhibition of cell proliferation and proteoglycan synthesis.

The effect of human recombinant interferon-gamma (IFN-gamma) on cultured human cartilage cells was studied by 2 variables: cell proliferation and proteoglycan synthesis. Cell proliferation was determined from 3H-thymidine incorporation rates in monolayer cultured chondrocytes. Proteoglycan synthesis was determined from 35S incorporation rates in monolayers and in chondrocytes cultured in agarose gel. IFN-gamma concentrations used in these experiments ranged from 10(-6) micrograms/ml (0.025 U/ml) to 10(-2) micrograms/ml (250 U/ml). The lowest concentrations are comparable with the synovial fluid levels in inflamed joints of patients with rheumatoid arthritis. At these concentrations, IFN-gamma was found to induce a dose dependent decrease of cell proliferation and of proteoglycan synthesis in monolayer cultured human chondrocytes. The decrease of proteoglycan synthesis was ascribed both to an inhibition of the proteoglycan protein core production and to a downregulation of the glycosaminoglycan chain elongation.

Cartilage, Articular↗
PubMed1991

The physiologic response of CPR training.

STUDY OBJECTIVE: To determine the physiologic response of CPR training. DESIGN: Cardiovascular and ventilatory parameters were investigated during 40 minutes of CPR performance and during a maximum exercise test in seven female and nine male subjects (mean age, 30 years; range, 16 to 49 years). RESULTS: During CPR performance, mean oxygen consumption (0.36 +/- 0.10 L/min), and mean minute volume (21.9 +/- 6.0 L/min) were 16% and 26%, respectively, of the levels reached during a maximum exercise test. Systolic blood pressure (153 +/- 23 mm Hg) and heart rate (132 +/- 25 beats/min) were 75% and 73%, respectively, of the levels reached during a maximum exercise test. Serum lactate levels at rest and after CPR performance were not significantly different (1.08 +/- 0.99 vs 1.54 +/- 1.03 mEq/L). Valsalva reflex remained present throughout total CPR time at varying degrees depending on individual differences in CPR technique (eg, incomplete extension of the manikin's head, holding the breath during chest compression). CONCLUSION: CPR performance seems to be a primarily aerobic effort that induces changes in cardiorespiratory parameters that were reasonably well tolerated by our study population.

Adolescent↗
PubMed1990

Proteoglycan metabolism in isolated chondrocytes from human cartilage. Influence of niflumic acid.

The effect of niflumic acid on hyaluronic acid and proteoglycan metabolism of human cartilage cells was investigated in vitro. Cartilage cells were obtained from five different donors. Niflumic acid levels used in the test systems ranged from 0 to 22 microgramsr/ml and were comparable to serum concentrations in humans after oral intake. Niflumic acid increased the synthesis rates of proteoglycan in some batches of isolated and monolayer-cultured chondrocytes. The effect on hyaluronate synthesis was less pronounced. The fact that this increase in the synthesis of proteoglycan was restricted to some of the donors whereas isolated cells or tissue samples from other individuals remained unaffected illustrates the heterogeneity of different human donors. Depression of proteoglycan synthesis in the presence of the drug was never observed.

Carbon Radioisotopes↗
PubMed1990

Proteoglycan metabolism in tissue-cultured human articular cartilage. Influence of niflumic acid.

Proteoglycan metabolism was investigated in tissue-cultured human cartilage. Normal cartilage obtained from a normal joint showed improving accumulation rates for 35S-labelled proteoglycans over a 3-6 weeks' period. The loss of newly synthesized molecules in the nutrient media was low and constant throughout culture. A decrease in accumulation of 35S-proteoglycan was observed in visually intact cartilage from joints showing foci of osteoarthrosis. This decrease was more pronounced in fibrillated cartilage. No clear effect on proteoglycan metabolism was observed when normal cartilage samples from the normal joint were incubated for several weeks in a nutrient medium containing niflumic acid. However, the cartilage samples from this donor tended to retain more proteoglycan aggregates in the intercellular matrix after a 6-weeks culture period in the presence of this NSAID. When niflumic acid was added to the incubation media of visually intact samples from pathological joints, significantly more newly synthesized proteoglycans were retained in the intercellular matrix. The effect was also observed and was more pronounced in the fibrillated cartilage samples.

Adolescent↗
PubMed1990

Onset of symptoms of rheumatoid arthritis in relation to age, sex and menopausal transition.

In a population of 564 patients with rheumatoid arthritis (RA), the onset of symptoms has been studied in relation to age, sex and last menstrual period for women. Median age of menopause was 49 years (3rd percentile: 32 years and 97th percentile: 56 years). Median age of first symptoms was 45 years in women and 50 in men. The individual interval between menopause and first symptoms has a Gaussian distribution with mean at time 0, implying that the average woman develops the first symptoms at the time of her menopause. The F:M ratio of all patients was 2.3; with increasing age the F:M ratio decreased from 3.7 before 30 years of age to 1 after the 6th decade of life, with a peak at the age of 40-44 years. A possible effect of age related changes in sex hormone levels on the pathogenesis of RA is suggested.

Adult↗
PubMed1990

"Microgel diffusion blotting" for sensitive detection of antibodies to extractable nuclear antigens.

A fast immunoblotting procedure, termed "microgel diffusion blotting," is used to detect and identify antibodies to extractable nuclear antigens (i.e., to Sm, RNP, and SSB) in patients with rheumatic diseases. The method differs from the standard immunoblotting techniques by the use of ultra-thin microgels for polyacrylamide gel electrophoresis: the very thin gel layer allows transfer of proteins to a nitrocellulose membrane by simple diffusion. Principal advantages of this variant technique are its simplicity, rapidity, and reproducibility--characteristics that make the test suitable for routine application. We compared the sensitivity of the test with that of double immunodiffusion in agarose for the evaluation of humoral antinuclear immunity. Microgel diffusion blotting detected antibodies in serum at concentrations less than 0.001 of those detectable by immunodiffusion.

Antigens, Nuclear↗