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Biomedical subjects

B Henderson

Publications and source records attributed to B Henderson.

At least 127 records · Page 7Linked to original sources
PubMed1993

Immunohistochemical identification of leucocyte populations in normal tissue and inflamed synovium of the rabbit.

A panel of monoclonal antibodies which recognizes well-defined markers of rabbit leucocytes has been used in an immunohistochemical survey of normal rabbit spleen, thymus, and liver, and of inflamed synovial tissue. The results demonstrate that these antibodies are well suited for the identification of leucocytes in frozen sections of rabbit tissues and that T lymphocytes, macrophages, and neutrophils can be readily distinguished. Antibodies to CD44 differentiate between medullary and cortical thymocytes, with the cortical cells being almost entirely negative for this marker. Antibodies to RLA class II show that periportal lymphocytes in the liver express RLA-DR but not RLA-DQ. The type A cells of the synovial lining from inflamed joint tissue are stained by antibodies that recognize macrophages in a manner similar to that found in the human synovial lining.

Animals↗
PubMed1993

Temporomandibular joint synovial fluid analysis.

A method for the estimation of the synovial fluid volume of the temporomandibular joint (TMJ) is described. Patients are administered 1.2 g of aspirin and the concentration of salicylate in plasma and in saline aspirates of the TMJ is measured by a sensitive high performance liquid chromatography assay. The ratio of the concentration of salicylate in the saline aspirate to that in the plasma allows the volume of the synovial fluid to be calculated. The method would also allow the determination of the concentration and the absolute amount of putative mediators of pathology in the upper joint.

Adolescent↗
PubMed1993

Biological activities of surface-associated material from Porphyromonas gingivalis.

Surface-associated material (SAM) from Porphyromonas gingivalis was tested for in vitro biological activities that may be relevant to the pathogenesis of chronic periodontitis. SAM was found to stimulate bone resorption at a concentration of 1.0 microgram/ml and this was inhibited by indomethacin, interleukin-1 receptor antagonist protein and anti-tumour necrosis factor antibody. At a concentration of 10 ng/ml, the SAM inhibited DNA and collagen synthesis in osteoblasts and murine calvaria and DNA synthesis in fibroblasts, monocytes and epidermal cells. Therefore, easily solubilised surface components from P. gingivalis could play a role in the pathogenesis of chronic periodontitis if these activities operate in vivo.

Animals↗
PubMed1993

Immunocytochemical localization of inflammatory cytokines and vascular adhesion receptors in radicular cysts.

Odontogenic cysts are one of the commonest bone destroying lesions of the maxillofacial skeleton, with the inflammatory radicular cyst being the commonest jaw cyst. Explants of radicular cysts produce an interleukin-1-like activity which could explain the osteolysis seen with these tumours though the cellular source of this osteolytic activity is unknown. In the present study, cytokines with known inflammatory and osteolytic activity: interleukin-1 (IL-1), tumour necrosis factor (TNF), interleukin-6 (IL-6), and the chemotactic cytokine interleukin-8 (IL-8) have been localized immunocytochemically in radicular cysts. The cellular adhesion receptors ICAM-1 and ELAM-1 have also been immunolocalized. All specimens showed positive staining for IL-1 (alpha and beta) and IL-6, with these cytokines being located in epithelial and vascular endothelial cells. Only two specimens demonstrated TNF and IL-8 staining, which was located in macrophages. All specimens demonstrated ELAM-1 staining in endothelium and ICAM-1 staining in epithelium, endothelium and mononuclear cells. These findings show that radicular cysts contain two bone-modulating cytokines, IL-1 and IL-6, and that these appear to be synthesized mainly by the epithelial cells. Cysts also contain a proportion of activated blood vessels whose endothelial cells express the cellular adhesion receptors ICAM-1 and ELAM-1.

Alveolar Bone Loss↗
PubMed1993

Higher-titer antisera from patients with periodontal disease inhibit bacterial capsule-induced bone breakdown.

Solubilized surface-associated material (SAM) from a number of periodontopathogenic bacteria have been shown to be potent stimulators of bone resorption in vitro in the murine calvarial bone culture assay. Antibodies to the constituents of SAM are also found in patients with periodontal diseases. Serum from patients with severe generalized periodontitis (SGP) containing high titers of antibodies to the SAM of Porphyromonas gingivalis completely inhibited the bone resorption induced by SAM from this organism. In contrast, serum from patients with low titers of antibodies to SAM from P. gingivalis failed to inhibit bone resorption. High-titer sera (containing antibodies to SAM from Actinobacillus actinomycetemcomitans) from patients with localized juvenile periodontitis (LJP) were added to calvarial cultures stimulated with SAM from A. actinomycetemcomitans. Of 6 high-titer sera tested, only 4 inhibited bone breakdown, the other 2 sera having no effect on resorption. Low-titer sera were also ineffective at blocking bone resorption. This suggests that the antibody response to SAM may have a protective effect in patients with periodontal disease.

Aggregatibacter actinomycetemcomitans↗
PubMed1993

Photosensitization with bacteriochlorins.

Biophysical and photobiological properties of a group of bacteriochlorins were compared with efficacy of these products for photodynamic therapy of murine tumors. Predictive factors for selective photosensitization in vivo include affinity binding to lipoproteins greater than albumin, extinction coefficient at the wavelength of irradiation and tumor/skin distribution. Efficacy was correlated with circulating plasma levels of the different sensitizers but not with the photodynamic therapy response in cell culture.

Animals↗
PubMed1993

Trends in research in two general psychiatric journals in 1969-1990: research on research.

OBJECTIVE: The authors describe the characteristics of psychiatric research over the past two decades as captured in the articles published by two general psychiatric journals. METHOD: A total of 1,236 articles were drawn from The American Journal of Psychiatry and Archives of General Psychiatry for October through September 1969-1970, 1979-1980, and 1989-1990. Articles were assigned to one of five categories. Research articles were then further categorized as to methodological approach and field of research as well as specific topic areas. Funding sources listed for each research article were also indexed. RESULTS: Over time and in both journals, the percentage and number of research articles have risen, with a concomitant reduction in case reports, opinion papers, and "other" articles. Categories of research design were fairly consistent across time and in both journals. Percentages of articles on specific fields and topics indicated an increasing emphasis on biological studies, especially those in clinical psychobiology, as well as a sharp move away from general categories to a more disorder-specific orientation. Reporting of funding sources has substantially increased. CONCLUSIONS: The large proportion of research articles published in these two important general psychiatric journals reflects editorial policies, changing audience expectations, and the availability of new research tools. Systematic analysis of trends in psychiatric research and other forms of research on research can be useful approaches to assessing the growth and utilization of knowledge in the field, to planning how to most effectively use limited research resources, and to increasing public support for research.

Humans↗
PubMed1993

Involvement of cytokines and vascular adhesion receptors in the pathology of fronto-ethmoidal mucocoeles.

Fronto-ethmoidal mucocoeles have the capacity to destroy bone. Sinus lining tissue has been obtained at surgery from patients with mucocoeles, from those with chronic sinusitis undergoing endoscopic sinus surgery and from patients undergoing craniofacial resection. Tissues have been frozen, sectioned, and subjected to immunohistochemical examination with monospecific antibodies for the presence of the potent osteolytic cytokines interleukins-1 and -6 and tumour necrosis factor alpha. In addition, the chemotactic intercrine--interleukin-8 was investigated. The presence of the cytokine-inducible vascular endothelial adhesion receptors--Inter-Cellular Adhesion Molecule (ICAM)-1 and E-Selectin (also known as Endothelial Leukocyte Adhesion Molecule--ELAM) was also determined. Normal sinus tissue showed no immunoreactivity with the antibodies to these various moieties. Surprisingly, only a small proportion of tissues from patients with chronic sinusitis showed the presence of cytokines or vascular adhesion receptors. In contrast, all specimens of fronto-ethmoidal mucocoeles showed positive staining for IL-1 alpha and beta and for ICAM-1 and E-selectin. IL-1 immunostaining was restricted to the epithelial cell population not being found in infiltrating leukocytes. In 40% of mucocoeles infiltrating macrophage-like cells showed the presence of tumour necrosis factor alpha. The presence of the potent osteolytic cytokine--IL-1 in all specimens of fronto-ethmoidal mucocoeles coupled to the finding of the IL-1-inducible adhesion molecules ICAM-1 and E-Selectin argues strongly that IL-1 is released from the epithelial cells and that this cytokine may be the factor causing the erosion of bone overlying the expanding mucocoele. The nature of the signals inducing cytokine synthesis remain, however, unidentified.

Adult↗
PubMed1993

Rabbit models of arthritis: immunolocalization of matrix metalloproteinases and tissue inhibitor of metalloproteinase in synovium and cartilage.

The distribution of the matrix metalloproteinases, collagenase, stromelysin, gelatinases A and B, and the tissue inhibitor of metalloproteinases in cartilage and synovium removed from rabbits up to 27 days after induction of two models of arthritis was investigated by immunolocalization. Following intra-articular injection of poly-D-lysine/hyaluronic acid coacervate, collagenase and stromelysin were found bound to cartilage matrix, but there was little increase in chondrocyte synthesis of these enzymes. The synovium underwent a complex wound healing response involving invagination and encapsulation of the coacervate and inflammatory cell debris, during which all four metalloproteinases and tissue inhibitor of metalloproteinase could be immunolocalized. The second model, intra-articular injection of ovalbumin into sensitized rabbits, caused considerable chondrocyte necrosis; collagenase was found bound to cartilage matrix on day 13, although again there was little evidence of synthesis by chondrocytes. Inflammatory cell infiltration of meniscoid synovia took place initially, followed by fibrosis involving macrophagelike cells secreting gelatinase A. In both models there was rapid loss of glycosaminoglycan metachromasia from the cartilage matrix. These results are discussed in relation to current knowledge of metalloproteinase involvement in the chronic rheumatoid synovial pannus erosion of cartilage in humans. The data suggest that there are considerable differences between rheumatoid arthritis and these models, and their use must therefore be carefully defined.

Animals↗
PubMed1992

Interleukin-1: the principal osteolytic cytokine produced by keratocysts.

Fragments of keratocysts removed at operation were maintained in explant culture and the media were assayed for the biological activity of the potent osteolytic cytokines--interleukin (IL)-1, interleukin (IL)-6 and tumour necrosis factor (TNF). Media were also assayed for their ability to stimulate bone resorption. All six cysts examined released IL-1 and IL-6 bioactivity but TNF bioactivity was unmeasurable. Dialysed cyst media stimulated bone resorption and this could be completely inhibited by a monospecific antibody which neutralized IL-1 alpha and IL-1 beta. Immunohistochemical staining of cryostat sections of keratocysts revealed the presence of IL-1 alpha and IL-6 in cyst epithelial cells but not in other cell types. Sections did not react with antibodies to IL-1 beta or TNF. It is therefore proposed that IL-1 alpha is the major osteolytic cytokine produced by keratocysts and that IL-6 and IL-1 may contribute to keratocyst growth by promoting epithelial cell proliferation and bone resorption, respectively.

Adult↗
PubMed1992

Anti-proliferative and cytotoxic activity of surface-associated material from periodontopathogenic bacteria.

The easily solubilized surface-associated material from three bacterial species associated with periodontal diseases, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Eikenella corrodens, produced dose-dependent inhibition of thymidine incorporation by human fibroblasts, the human monocytic cell line U937 and guinea pig epidermal cells. In contrast, lipopolysaccharides from A. actinomycetemcomitans and P. gingivalis were either inactive or substantially less active over the dose range tested. One of the constituents of surface-associated material from a 'non-leucotoxic' strain of A. actinomycetemcomitans was highly cytotoxic to human peripheral blood polymorphonuclear cells, with 50% killing from less than 1 ng/ml. A constituent of the surface-associated material from P. gingivalis was approximately one log order less active. The lipopolysaccharides from these bacteria were at least three log orders less active in neutrophil killing. These findings add weight to the hypothesis that easily solubilized exopolymers from periodontopathogens play a major part in the pathology of periodontal diseases.

Aggregatibacter actinomycetemcomitans↗
PubMed1992

Visual evoked cortical responses and electroretinograms following implantation of human fetal mesencephalon to the right caudate nucleus in Parkinson's disease.

Pattern electroretinograms and visual evoked cortical responses following flash and checkerboard pattern reversal stimulation were performed in 7 patients with advanced Parkinson's disease before and after implantation of human fetal ventral mesencephalon to the head of the right caudate nucleus. Six to nine months following surgery there was bilateral enhancement of flash-evoked response amplitudes. Electroretinogram measurements were unchanged. Individual increases in amplitude and decreases in latency were seen following pattern stimulation which were not statistically significant. A relationship between change in dyskinesia, and change in checkerboard pattern stimulation amplitude at 2.4 cycles per degree suggests that amplitude effects at this stimulus frequency are mediated via altered dopaminergic receptor status in the grafted hemisphere. This may be relevant to the mechanisms leading to generalised clinical improvements following this grafting technique.

Brain Tissue Transplantation↗
PubMed1992

Therapeutic potential of cytokine manipulation.

Interleukin 1 is just one of a large, growing, collection of potent cytokines that are produced by a variety of cells and have a myriad of overlapping activities. Many of these cytokines have important pathophysiological actions in diseases ranging from rheumatoid arthritis to AIDS. Selective inhibition of the synthesis or of the action of specific cytokines may have therapeutic benefit. In this review, Brian Henderson and Simon Blake discuss the ways in which cytokine function could be manipulated pharmacologically for therapeutic benefit.

Animals↗