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Biomedical subjects

G Verbruggen

Publications and source records attributed to G Verbruggen.

At least 73 records · Page 4Linked to original sources
PubMed1989

Microgel immunoblotting of thymus and nuclear extracts by unidirectional diffusion.

A variant immunoblotting procedure is presented, starting from sodium dodecyl sulfate-containing ultra-thin microgels. The use of these gels allows efficient transfer of proteins to an immobilizing matrix such as nitrocellulose, by simple uni-directional diffusion, without loss of resolution. To this end an assembly was developed, keeping the microgel and the immobilizing matrix in continuous contact. To standardize the technique, two protein extracts (a classical rabbit thymus extract and an original autologous nuclear extract) were used, together with reference antinuclear antisera. The method is fast, easy to perform, and perfectly reproducible. For these reasons, the technique is very suitable for screening a patient's sera on a large scale.

Alkaline Phosphatase↗
PubMed1989

Proteoglycan metabolism in tissue cultured human articular cartilage. Influence of piroxicam.

Proteoglycan metabolism was investigated in longterm tissue cultured human cartilage. Visually intact cartilage from adult donors showed improving accumulation rates for 35sulfate labelled proteoglycans over a 6-week period. The loss of newly synthesized molecules in the nutrient culture media was low and constant. Fibrillated cartilage from a 17-year-old male showed higher basal 35S incorporation rates and the proportions of 35S proteoglycan aggregates were higher than in normal tissue. These observations may reflect the immature status of the tissue or an attempt at repair. However samples lost increasing amounts of 35S proteoglycans in the incubation media. This material appeared to be monomeric proteoglycan. The amount of 35S activity retained in the fibrillated tissue matrix fell during culture as did the proportion of proteoglycan aggregates. Thus catabolic events were postulated in these fibrillated cartilage samples. When piroxicam was added to the incubation media more newly synthesized proteoglycans were retained in the intercellular matrix of the fibrillated samples. Increased accumulation of 35S activity was seen in some of the batches of visually intact cartilage.

Adolescent↗
PubMed1988

The diagnostic significance of the antiperinuclear factor for rheumatoid arthritis.

Sensitivity and specificity of antiperinuclear factor (APF) determination were assessed in 127 patients with classical or definite rheumatoid arthritis (RA). The control population consisted of 262 patients with rheumatic complaints other than RA. Our results showed a sensitivity of 86.6%, a specificity of 96.2% and a Youden index of 82.8% for APF in RA. In 14.2% of the total population with RA the rheumatoid factor (RF) became negative in the course of the disease; all but one were found to be actually APF positive. Of the population with RA analyzed, 8.6% were consistently RF negative but APF positive. In view of its strong sensitivity and specificity for RA, APF determination is a valuable serological tool for the diagnosis of the disease. In APF positive, RF negative patients with RA the prognosis seems to be poor.

Adult↗
PubMed1988

Interferon gamma in rheumatoid arthritis--a double blind study comparing human recombinant interferon gamma with placebo.

A double blind trial comparing recominant interferon gamma (IFN gamma) with placebo in rheumatoid arthritis is presented. Twenty-six patients entered the study and 22 completed the 6-month period. IFN gamma was administered subcutaneously as was placebo; the 1st week, patients treated with the active compound received a daily subcutaneous injection of 100 micrograms of IFN gamma and for the following 23 weeks the schedule was decreased to 2 injections of 100 micrograms every week. No serious side effects were observed. After Week 24 the group treated with the active compound showed a significant decrease of the joint tenderness score and the placebo group showed a significant increase of the number of subcutaneous nodules. All other variables shifted in favour of the active compound but not significantly. More double blind trials with a larger number of patients and using other treatment schedules or other routes of administration are required.

Arthritis, Rheumatoid↗
PubMed1987

Disease manifestations of progressive systemic sclerosis: sensitivity and specificity.

The authors conducted a study of 47 patients with a diagnosis of systemic sclerosis in order to determine the sensitivity, specificity and Youden index and consequently the diagnostic value of the generally accepted criteria and of some other common disease features. The control population consisted of 324 patients with rheumatoid arthritis and 35 patients with systemic lupus erythematosus. In addition to proximal scleroderma, the presence of which was required for inclusion in this study, other disease features score a high to moderate Youden index: sclerodactyly, Raynaud's phenomenon, appearance of perioral grooves, cinematographic evidence of esophageal hypomotility, periarticular calcifications, widening of the periodontal membrane on teeth radiographs and specific histologic changes on fingertip biopsy. Finally, a good correlation was found with most of the ARA subcommittee criteria.

Adult↗
PubMed1987

The effect of low doses of prednisolone on T-cell subsets in rheumatoid arthritis.

Prednisolone intake causes a drop in the absolute numbers of circulating T-cell populations. OKT4+ (helper-inducer) cells are more susceptible to this. Higher doses are needed to depress OKT8+ (suppressor-cytotoxic) cell numbers. Administration of up to 10 mg prednisolone affects the suppressor-cytotoxic (OKT8+) absolute cell numbers only in patients with initially low OKT4+/OKT8+ ratios and not the values of OKT8+ cells in patients with high OKT4+/OKT8+ ratios, since these patients already have low OKT8+ cell counts.

Administration, Oral↗
PubMed1987

Clinical manifestations in HLA-B27-positive patients.

The clinical manifestations of rheumatic diseases have been studied in a population of 440 HLA-B27-positive patients. Fifty-eight per cent had peripheral joint involvement. After statistical analysis and clustering of characteristics, three patterns of peripheral joint involvement were found. They were referred to as the X, Y and Z type for mnemotechnical reasons. The X type includes male patients with sacroiliitis, spondylitis, uveitis and uni- or bilateral arthritis of hip and/or shoulder. Y type patients present sacroiliitis, pauci-articular asymmetrical joint involvement and tendinitis. Z type patients are characterized by sacroiliitis, polyarticular symmetrical joint involvement and a positive IgM rheumatoid factor. This classification enables a new approach to the pathology, diagnosis and therapy of the seronegative spondyloarthropathies.

Adolescent↗
PubMed1987

In vitro repair potential of articular cartilage: proteoglycan metabolism in the different areas of the femoral condyles in human cartilage explants.

We tested the hypothesis that metabolism of individual cartilage samples, such as those which might be taken at arthroscopy, could reflect the overall intrinsic reparative response of the cartilaginous tissue of that joint. Full thickness samples of articular cartilage, removed from the anteromedial, anterolateral and posterolateral areas of the femoral condyles of 2 normal knees, were placed in tissue culture separately. The incorporation of 14C-glucosamine into matrix molecules, especially proteoglycan, was measured. Three slices of each area were removed after one, 3 or 6 weeks of in vitro culture. The extracted matrix molecules and the media were analyzed and the relative amount of radioactive proteoglycan and proteoglycan aggregates, as well as the total amount of radiolabelled proteoglycan/mg dry weight, were calculated. A progressive increase in these variables during the culture period was demonstrated, suggesting an attempt at repair of the articular cartilage in this in vitro condition. No differences in the incorporation dynamics were found between the anteromedial, anterolateral and posterolateral areas of both subjects.

Cartilage, Articular↗
PubMed1986

Peripheral blood T lymphocyte subpopulations determined by monoclonal antibodies in active rheumatoid arthritis.

The introduction of an automated flow cytofluorograph has facilitated the detection of T lymphocyte subsets because it enables a larger number of cells to be analyzed. Many authors have reported a decrease of cytotoxic/suppressor T lymphocytes in rheumatoid arthritis (RA), in contrast to the results of other workers. We believe that the discrepancy between the various studies is due to the fact that different methods and different criteria for patient selection were used. Our study comprised a larger number of patients which makes the results suitable for statistical inference. Disease activity is clearly defined and all drugs that could alter the results were excluded. The use of a flow cytometer enhances the reliability of T lymphocyte subset determination by monoclonal antibodies (OKT series). Our study confirms the reports, which suggested that the number of suppressor/cytotoxic T lymphocytes (OKT8+ cells/mm3) is decreased in patients with active RA, resulting in a high T helper/inducer lymphocyte/T suppressor/cytotoxic lymphocyte ratio (OKT4+:OKT8+). This immune balance represents an interesting feature of the disease, since several active antirheumatic drugs share a common immunomodulatory action, which normalizes the OKT4+:OKT8+ ratio. Finally, we found a good correlation between the OKT4+ cells and OKT8+ cells in the normal control population. This observation enabled us to isolate a subgroup of active patients with RA not responding to slow acting antirheumatic drugs and characterized by a low OKT4+:OKT8+ ratio.

Adult↗
PubMed1985

Repair function in organ cultured human cartilage. Replacement of enzymatically removed proteoglycans during longterm organ culture.

The effect of enzymatic removal of proteoglycans (PG) from the extracellular matrix of human articular cartilage on subsequent PG metabolism of the remaining chondrocytes was investigated for periods of up to 12 weeks. Chondrocytes resynthesized normally aggregated PG but these macromolecules failed to stabilize in the intercellular matrix of the organ cultured explants and consequently diffused into the nutrient medium. After being in culture for about 2 months the chondrocytes no longer compensated for this PG loss and ceased to synthesize these biopolymers. A shift towards hyaluronic acid synthesis--as seen in dedifferentiated chondrocyte cultures--was not observed during the culture period. In this model some attempts at repair were demonstrated.

Cartilage, Articular↗
PubMed1984

Lymphocyte sub-population counts after a single 40 mg administration of piroxicam in 20 patients with rheumatoid arthritis. A placebo-controlled study.

Patients with active rheumatoid arthritis are characterized by a decrease in the number of circulating T-suppressor lymphocytes (identified by OKT8), resulting in an imbalance between helper (identified by OKT4) and suppressor cells. Piroxicam is a non-steroidal anti-inflammatory agent which modulates lymphocytic functions, especially by reducing the concentration of the rheumatoid factor in vitro and in vivo. A double-blind placebo-controlled study was performed in 20 patients suffering from active RA to investigate the acute effect of a single administration of piroxicam 40 mg on the number of circulating OKT3, T4, T8 and IA1 positive cells. Blood samples were obtained 16 hours before and 0, 2, 6, 8, 24, 48, and 72 h after administration of piroxicam or placebo. There was a significant decrease (P less than 0.05) in T4/T8 cell ratio 48 and 72 h after piroxicam, whereas placebo had no effect. There were no significant changes in absolute numbers of total T-lymphocyte (OKT3 positive cells), T-helper-inducer (OKT4 positive cells) and T-suppressor cytotoxic lymphocytes (OKT8 positive cells). The number of IA1 positive cells (B-cells and activated T-lymphocytes) was significantly higher in the afternoon samples (at 14.00 and 16.00 hours) than in the morning samples (at 08.00 and 10.00 hours) after both placebo and piroxicam administration (P less than 0.05). These data show that piroxicam decreases the T4/T8 cell ratio in active RA, but only 48 h after the first administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Salicylate-induced occult gastrointestinal blood loss: comparison between different oral and parenteral forms of acetylsalicylates and salicylates.

Gastrointestinal fecal blood loss, determined by injecting 51Cr-labelled autologous red blood cells, was measured in 191 orthopaedic patients after oral or parenteral intake of different forms of acetylsalicylates or salicylates. Oral or parenteral administration of non-acetylated salicylates caused nearly no gastrointestinal bleeding, but the anti-inflammatory activity of these products can be questioned since they cannot inhibit prostaglandin synthetase. Buffered, soluble forms of acetylsalicylates caused gastrointestinal bleeding in more than 50% of the patients. However, enteric-coated and intravenous forms resulted in significantly less gastrointestinal bleeding. For both preparations a relationship between serum salicylate level and amount of fecal blood loss was found in the group of "bleeders" (an upper limit of physiological blood loss could definitely be determined by this method). The findings suggested a similar mode of action of enteric-coated and intravenous acetylsalicylates on gastric mucosa through a systemic action. It was concluded that in long-term anti-inflammatory salicylate treatment, enteric-coated forms are probably the galenic form of first choice.

Administration, Oral↗
PubMed1984

Thymopoietin pentapeptide (thymopentin, TP-5) in the treatment of rheumatoid arthritis. A compilation of several short- and longterm clinical studies.

Thymopentin (TP-5), the active side of thymopoietin, was shown to affect immunoregulation. The effect of this drug in the treatment of rheumatoid arthritis (RA) was evaluated. Three trials were performed: a six month double-blind trial comparing TP-5 administered subcutaneously to placebo at 3 different dosages, an open longterm study in which the same dosage of the drug was administered subcutaneously, and a shortterm (3 weeks) double-blind trial in which the drug was given intravenously at a high dosage (100 mg/day). In none of these 3 studies were statistically significant improvements registered in the TP-5 treated patients, although there were important improvements in individual patients. Serious side effects were not encountered, but the majority of patients did not improve or were withdrawn because of ineffectiveness. The beneficial effect of TP-5 on the clinical evolution of RA, reported elsewhere, could not be confirmed by these studies.

Arthritis, Rheumatoid↗