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Biomedical subjects

P A Revell

Publications and source records attributed to P A Revell.

At least 19 recordsLinked to original sources
PubMed1992

Localisation and characterisation of substance P binding to human synovial tissue in rheumatoid arthritis.

The neuropeptide substance P is found in perivascular and free unmyelinated nerve fibres in human synovial tissue. Quantitative receptor autoradiography was used to show specific, high affinity (Kd = 0.75 (0.21), nmol/l (mean (standard error of the mean)), low capacity (Bmax = 27.8 (7.9) amol/mm2) binding sites for substance P Bolton Hunter-labelled with iodine-125 localised to vascular endothelial cells in human synovial tissue. The binding could be saturated, was reversible, and was dependent on the magnesium concentration. Unlabelled substance P and neurokinin A competitively inhibited specific binding with 50% inhibition at concentrations of 1.25 (0.21) and 175 (29) nmol/l respectively. Neurokinin B (mumol/l) and calcitonin gene related peptide (1 mumol/l) did not inhibit binding. These binding sites show characteristics of the neurokinin 1 tachykinin receptor subtype. This provides further evidence that substance P may play a part in the vascular control of human synovium and may influence inflammatory processes in joints.

Adult↗
PubMed1992

Remodelling of subchondral bone in osteoarthritis: a histomorphometric study.

AIMS: To determine whether remodelling of subchondral bone in osteoarthritis is related to anatomical and mechanical factors operating on the joint surface. METHODS: Ten femoral heads were examined. Patients due to have the femoral head removed because of osteoarthritis were given a double tetracycline label before surgery. The specimens were divided in three roughly equal parts, corresponding to the medial, central (weight bearing), and lateral aspects of the femoral heads. Undecalcified methylmethacrylate embedded sections were prepared. The subchondral bone was assessed for appositional bone formation by ultraviolet light microscopy, for resorptive activity by osteoclast count, and for trabecular bone volume by semiautomatic computerised image analysis. Appositional bone rate was also correlated with the presence or absence of overlying cartilage. RESULTS: Bone density was reduced in the medial aspect of the femoral heads but there was no significant difference between the appositional bone rate or the resorptive activity in the three areas. Nor was there any correlation between appositional bone rate in the subchondral bone and the presence or absence of overlying cartilage. CONCLUSION: Remodelling of subchondral bone in osteoarthritis, at least in the short term, is fairly constant and is not related to weight bearing.

Aged↗
PubMed1991

A comparative study by morphometry of the microvasculature in normal and rheumatoid synovium.

Vascularity is said to be increased (subjectively) in rheumatoid arthritis, yet synovial fluid is hypoxic and acidotic. Morphometry by image analysis was used to quantify vascularity in normal and rheumatoid synovium from the knee joint. Capillaries were distributed more deeply in the rheumatoid synovium (93.3 microns, compared with 32.5 microns in normal synovium) and were significantly less densely arranged (80.2/mm2 rheumatoid, 241.5/mm2 normal). The blood volume fraction fell from 2.9% in normal knee synovium to 1.2% in rheumatoid synovium. These results imply that there is impairment of O2 transfer, which contributes to the intraarticular hypoxia, in rheumatoid arthritis.

Adult↗
PubMed1991

The effect of hydroxyapatite coating on ingrowth of bone into cavities in an implant.

A canine implant study was performed to assess whether hydroxyapatite (HA) could induce bone to close gaps at the bone-prosthesis junction. Titanium alloy (TiAlV) plates with varying grooves cut into them (1, 2, and 3 mm deep) and identical on both sides were sprayed on one side with HA and left as bare metal on the other. These were then implanted into the distal femora of dogs that were killed 4 and 8 weeks afterwards. Specimens were analyzed using optical microscopy and microradiography. Results show that the presence of HA induces bone to grow almost completely down the deepest groove by 8 weeks. In the 1- and 2-mm grooves at 4 weeks the depth of penetration of bone into the grooves was greater on the HA coated side (but the actual volume of bone in the grooves was greater on the TiAlV side because the bone present was more dense). We conclude that the presence of HA induces bone to close relatively large gaps. Although bone does not grow all the way into uncoated defects there can be more bone here in the short term. This feature of HA may be of great value in hip implant fixation.

Animals↗
PubMed1991

Sensitivity to titanium. A cause of implant failure?

Tissues from five patients who underwent revision operations for failed total hip replacements were found to contain large quantities of particulate titanium. In four cases this metal must have come from titanium alloy screws used to fix the acetabular component; in the fifth case it may also have originated from a titanium alloy femoral head. Monoclonal antibody labelling showed abundant macrophages and T-lymphocytes, in the absence of B-lymphocytes, suggesting sensitisation to titanium. Skin patch testing with dilute solutions of titanium salts gave negative results in all five patients. However, two of them had a positive skin test to a titanium-containing ointment.

Antibodies, Monoclonal↗
PubMed1990

Type IV collagen and laminin in the synovial intimal layer: an immunohistochemical study.

The distribution of type IV collagen and laminin in the intimal layer of rheumatoid, osteoarthritic, traumatic and normal human synovium was determined by immunohistochemistry using polyclonal and monoclonal antibodies. All samples showed a similar pattern of labelling with type IV collagen and laminin present around the synovial intimal cells. Type IV collagen has previously only been identified in association with basement membranes which are not found at this site. Two major basement membrane components around synovial cells suggest the formation of a modified basement membrane-like structure.

Arthritis, Rheumatoid↗
PubMed1990

A monoclonal antibody (Mab 67) marks type B synoviocytes.

The functionally important lining cells of the synovium (types A and B synoviocytes) are the subjects of much study but have presented problems with their characterization and microscopical identification, particularly at the light level. Type A (macrophage-like) synoviocytes, however are more easily localized than the type B (fibroblast-like) variety because of the greater availability of antimacrophage antisera. We describe, using light and electron microscopy, a monoclonal antibody which in the synovial intimal layer is specific for type B synoviocytes.

Antibodies, Monoclonal↗
PubMed1990

Synovial fluid fibronectin fragments: no evidence for a mitogenic effect on fibroblasts.

Fragments of bovine plasma fibronectin produced by cathepsin D digestion are reportedly mitogenic for hamster fibroblasts. Rheumatoid arthritis synovial fluid contains many fibronectin fragments, which may contribute to the proliferation of synovial cells. We have therefore investigated the potential of fibronectin fragments to stimulate proliferation of synovial fibroblast-like cells using human material. Affinity-purified human plasma and synovial fluid fibronectin was digested with cathepsin D at pH 3.5 for 0-18 h and proteolysis stopped with pepstatin. A variety of fragments were produced ranging from 50 to 200 kDa when analysed by SDS-PAGE. The proliferative activity of various test preparations was studied using quiescent human skin and synovial fibroblasts. Tests were applied for 24 h to 10(4) cells and DNA synthesis measured by tritiated thymidine incorporation. Both undigested and peptides of fibronectin consistently failed to stimulate DNA synthesis in fibroblasts at all concentrations tested, compared with a phosphate-buffered saline control. This was in marked contrast to human synovial fluid from either rheumatoid arthritis or osteoarthritis patients, which stimulated DNA synthesis in the same system (P less than 0.01). Therefore, our data do not confirm the findings of previous studies in which animal materials were used. We can find no evidence that fibronectin fragments play a role in stimulating synovial proliferation in inflammatory arthritis.

Arthritis, Rheumatoid↗
PubMed1990

Metabolic activity in the calcified zone of cartilage: observations on tetracycline labelled articular cartilage in human osteoarthritic hips.

The tidemark is a metabolically active zone in the calcified layer of the cartilage in which it is possible to show that there is calcifying activity even over a short period of time using a tetracycline labelling technique. The tidemark slowly advances in the direction of the non-calcified cartilage and analysis of double-tetracycline labelled cartilage shows that this is not an appositional phenomenon like that occurring in bone, but that, where present, several tidemarks can be labelled at the same time. Each tidemark may therefore be metabolically active and it is not just the tidemark adjacent to hyaline cartilage which incorporates calcium.

Bone Development↗
PubMed1990

Substance P-, calcitonin gene-related peptide- and C-flanking peptide of neuropeptide Y-immunoreactive fibres are present in normal synovium but depleted in patients with rheumatoid arthritis.

By means of antisera to cytoplasmic components of nerve fibres and neuropeptides which are known to be present in sensory or sympathetic nerves we have examined the distribution of both total and different types of nerve fibres in normal and inflamed human synovial tissue. Samples of synovia were obtained at surgery from five normal and five rheumatoid patients (age range 10-77 years). In order to map the overall neural innervation of the synovium, antiserum to the general neuronal marker protein gene product 9.5 was employed. Substance P and calcitonin gene-related peptide antisera were employed to identify sensory fibres and antisera to the C-flanking peptide of neuropeptide Y to distinguish sympathetic nerves. In normal synovium protein gene product 9.5-immunoreactive fibres were numerous, in particular, the vasculature was densely innervated. Free protein gene product 9.5-immunoreactive fibres were less numerous but were present in all synovia examined, and in many cases these extended to the intimal layer. Neuropeptide immunostaining was predominantly found in perivascular networks. Fibres immunoreactive for the C-flanking peptide of neuropeptide Y were exclusively located around blood vessels whereas free fibres were immunoreactive for substance P or calcitonin gene-related peptide. As with free protein gene product 9.5-immunoreactive fibres, fibres expressing substance P or calcitonin gene-related peptide immunoreactivity were often seen in the intimal cell layer. In rheumatoid arthritis a similar innervation to that seen in normal synovium was apparent in the deep tissue but fibres immunoreactive for protein gene product 9.5, the C-flanking peptide of neuropeptide Y, substance P or calcitonin gene-related peptide were not visible in the more superficial tissues or the intimal cell layer. In addition, immunostaining of neuropeptides in the deep tissue was weaker in the diseased tissues than in normal controls. The data unequivocally demonstrate that synovial tissues are richly innervated and confirm the presence of both sensory and sympathetic nerves. The absence of nerves which innervate the superficial synovium in rheumatoid arthritis might suggest that there is increased release of substance P, calcitonin gene-related peptide and the C-flanking peptide of neuropeptide Y, reducing the stores in the nerves to levels below that detectable by immunocytochemistry. However, since protein gene product 9.5-immunoreactive nerves were not seen in the inflamed tissue it is probable that synovial growth outflanks neural growth and consequently as the disease progresses neural structures become restricted to deeper tissues.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1990

ICLH double-cup arthroplasty, 1980-1987.

The results are presented of 92 double-cup arthroplasties modified in light of previously published experience. The review period lasted up to 7 years after operation. Eighty-six had a metal femoral component and six had a ceramic femoral component. Forty metal femoral cups were matched with a cemented acetabulum, while with 46 the acetabular implant was cementless. The overall revision rate for the metal femoral cups was 23.3%, and a further 31.8% demonstrated radiological signs suggestive of loosening. There was no difference between the cemented and uncemented cups in terms of revision rates or clinical results. The clinical results of those hips that have not yet loosened were excellent. A histological study showed that femoral lossening was associated with an erosive cellular response. Surface arthroplasty of the hip with current materials should be abandoned.

Adult↗
PubMed1989

The use of foetal calf serum as a blocking agent in double immunoenzyme-cytochemistry labelling with mouse monoclonal antibodies.

Double immunoenzyme labelling has progressed in the past few years to double labelling using monoclonal antibodies (MAB) raised in the same species. It presents the problem of cross-reaction between the primary antibodies and the enzyme-labelled secondary antibodies as well as that of excessively high background staining. These difficulties have been overcome in part by using normal mouse serum as a blocking agent. However, differentiation of the resulting colour reactions, and therefore interpretation of results, is difficult, especially when compounded by the presence of an intermediate colour due to the combination of two reactions. Because of this problem, normal mouse serum (NMS), BALB/c mouse serum and foetal calf serum (FCS) were tested for their effectiveness as blocking agents in a double-labelling procedure using two mouse anti-human MABs.

Animals↗
PubMed1989

Synovial lining cells.

The cells making up the lining of the synovium have long been known as type A and B synoviocytes, with an intermediate form sometimes also described. Accumulating evidence shows that the type A cells are macrophages and the type B cells are fibroblasts. Recently, a definite orientation of these cells within the synovial lining has been observed. The number of synovial lining cells increases in joint disease, and this now seems more likely to be due to cellular recruitment rather than local proliferation.

Animals↗
PubMed1989

The immunocytochemical demonstration of basement membrane deposition in transitional cell carcinoma of bladder.

We assessed the staining characteristics of the basement membrane of transitional cell carcinoma of bladder using a monoclonal antibody to type IV collagen. Basement membranes were clearly stained at the stromal/carcinoma interface. As transitional cell carcinoma became less well differentiated and the depth of invasion increased interruptions to basement membrane staining became more extensive and these findings are comparable to those described in similar series of transitional cell carcinoma using polyclonal antibodies to type IV collagen. The defects in basement membrane staining may be related to the degree and direction of tumour cell differentiation or may be explained by increased degradation compared to synthesis of basement membrane components. Demonstration of the basement membrane may be of value in diagnostic histopathology as a marker of the biological behaviour of transitional cell carcinoma of bladder.

Basement Membrane↗
PubMed1988

Ultrastructural characterisation of macrophages (type A cells) in the synovial lining.

The ultrastructural localisation of class II and macrophage antigens has been sought in the intimal layer of the human synovium. The cells described as type A in early morphological studies are shown to express both class II antigens and two markers of the macrophage/monocyte lineage of cells, OKM1 and MAB 24. The morphological type B cells were found to express none of these antigens. The findings are consistent with the idea that the synovial lining comprises two cell types, bone-marrow derived macrophages and mesenchymal fibroblasts.

Antibodies, Monoclonal↗
PubMed1988

The synovial membrane in osteoarthritis: a histological study including the characterisation of the cellular infiltrate present in inflammatory osteoarthritis using monoclonal antibodies.

Inflammatory infiltration of the synovial membrane has been described in a proportion of cases of osteoarthritis (OA). Using conventional histology, lymphoid follicles, diffuse fibrosis, and perivascular fibrosis were shown to be present to a significantly greater extent and in more synovial membranes in osteoarthritis than in those cases where there was a mechanical or traumatic background to the joint disease. Calcium pyrophosphate dihydrate crystals (five patients) and detritus fragments of bone and cartilage (seven patients) were present in small numbers of the total cases of OA (38) studied. Neither of these features was related to the presence of an inflammatory infiltrate. Examination of 20 osteoarthritic synovial membranes using monoclonal antibodies showed the presence of lymphoid follicles containing T helper and T suppressor lymphocytes, B lymphocytes, and macrophages expressing HLA-DR in five cases. The T helper:suppressor ratio varied between 1:1 and 2.5:1 in these follicles. In addition, half of the OA samples, including these five cases, showed the presence of a diffuse cellular infiltrate containing T and B lymphocytes and macrophages, which were HLA-DR positive. Granulocytes were present in this diffuse infiltrate in those cases containing lymphoid follicles. The results confirm the presence of an inflammatory form of osteoarthritis but also show that the proportions of lymphoid cells are not the same as those considered to be typical of rheumatoid arthritis.

Antibodies, Monoclonal↗