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Biomedical subjects

B Henderson

Publications and source records attributed to B Henderson.

At least 199 records · Page 11Linked to original sources
PubMed1982

The sensitivity to light of solutions of phenazine methosulphate: a quantitative cytochemical study.

The ability of phenazine methosulphate to transfer electrons from reduced coenzymes to a tetrazolium salt, neotetrazolium chloride, after exposure to light for various periods of time has been studied. Enzymes assayed for this purpose were: glucose-6-phosphate dehydrogenase been studied. Enzymes assayed for this purpose were: glucose-6-phosphate dehydrogenase (NADP+-dependent); lactate dehydrogenase (NAD+-dependent) and succinate dehydrogenase (flavoprotein-dependent). Enzyme activity was measured in sections of rodent liver by scanning and integrating microdensitometry. Phenazine methosulphate in solution was found to be sufficiently stable in light for up to two hours for reproducible quantitative measurements of cytochemical dehydrogenase activity to be obtained over this period.

Animals↗
PubMed1982

Cell division in the synovial lining in experimental allergic arthritis: proliferation of cells during the development of chronic arthritis.

The synovial tissue in experimentally induced immune arthritis induced in the rabbit has been used as a model of rheumatoid arthritis to determine which cells may contribute to the growth of this tissue. Tissue from the challenged and from the unchallenged knee joints was taken, after the intra-articular injection of a small amount of tritiated thymidine, from rabbits up to 3 months after the arthritis was induced. DNA synthesis, as a measure of cell proliferative activity, was assessed firstly by measuring the labelling index in autoradiographs of sections of such tissue, and secondly by the DNA synthetic index obtained by Feulgen cytophotometry. These measurements were made separately on synoviocytes, on the structural cells of the stroma, on the cells lining the small blood vessels, and on the infiltrating inflammatory cells. The DNA synthetic activity of the synoviocytes, and of the stromal noninflammatory cells, was maximal between 3 and 7 days after challenge. The activity in the synoviocytes, in particular, remained raised for up to 84 days after the challenge. Thus these cells appear to be capable of contributing to the hyperplasia, but the contribution of other cells, deeper in the stroma, cannot be excluded.

Animals↗
PubMed1982

Experimental allergic arthritis in the rabbit: alterations in the cellularity and the rate of cellular proliferation in the synovial linings of the challenged joints of rabbits immunized with antigen in Freund's incomplete adjuvant.

Rabbits have been immunized with ovalbumin in Freund's incomplete adjuvant (FIA) followed by the intra-articular injection of ovalbumin, in order to follow the development of inflammation in the synovial lining. The kinetics of cell proliferation have been investigated using tritiated thymidine (3HTdR) autoradiography and Feulgen cytophotometry. Unexpectedly, marked histological changes were found in the synovium, with hyperplasia of synoviocytes, and of the connective-tissue cells of the subintima, being seen as early as 3 days after challenge. Large numbers of inflammatory cells, including many plasma cells, were found in the synovium at between 5 and 11 days. Labelling of synoviocytes and connective-tissue cells reached a maximum at 3 days and declined thereafter, reaching normal levels at 14 days. Three weeks after challenge the synovium was normal in appearance.

Animals↗
PubMed1981

The influence on enzyme activity of storage of tissue blocks at -70 degrees C.

Blocks of tissue from various organs of the rat have been chilled by precipitate immersion in n-hexane cooled to -70 degrees C, and then stored at -70 degrees C. At various intervals (up to 14 days) after chilling, cryostat sections were prepared from these blocks and assayed for the activity of a variety of enzymes. Enzyme activity was measured by scanning and integration microdensitometry. With the exception of acid phosphatase and cytochrome oxidase, all enzymes assayed were stable for at least 7 days after storage at -70 degrees C and most were stable for 14 days, Storage of fresh-frozen sections at -30 degrees C in the cabinet of the cryostat, for up to 24 h, had little effect on enzyme activity.

Animals↗
PubMed1981

Intermediate electron-acceptors in quantitative cytochemistry. Comparison of phenazine methosulphate and Meldola Blue.

The efficacy of Meldola Blue (MB), a new intermediate electron-acceptor, has been compared with that of phenazine methosulphate (PMS) in the assay of oxidoreductase activity in cryostat sections; various tetrazolium salts have been used as the final electron-acceptors. Three enzymes: succinate dehydrogenase, glucose 6-phosphate dehydrogenase and lactate dehydrogenase were investigated, the activity in sections being quantitated by scanning and integrating microdensitometry. Phenazine methosulphate was superior to Meldola Blue in transferring reducing equivalents from reduced coenzyme to all the tetrazolium salts examined.

Animals↗
PubMed1981

The assessment of DNA-synthetic activity.

A method is described by which a numerical value can be assigned to the amount of DNA-synthesis shown graphically by population-histograms obtained by Feulgen cytophotometry. The index appeared to give a reasonable measure of DNA-synthetic activity in populations having very low, moderate and high mitotic indices and closely followed labelling indices obtained by autoradiography. Thus the advantage of a numerical value is that the DNA-synthetic activities in different populations can be compared for statistical analysis.

Animals↗
PubMed1981

Evidence for cell division in synoviocytes in acutely inflamed rabbit joints.

DNA synthesis has been measured both by Feulgen cytophotometry, quantified by the DNA synthesis index, and by tritiated thymidine autoradiography, quantified by the labelling index. In the early acute inflammation resulting from the intra-articular challenge of ovalbumin in sensitised rabbits both indices rose considerably, so that at least 1 in 10 synoviocytes was heavily labelled 3 days after challenge. The results are compatible with the concept that even such apparently differentiated synoviocytes are capable of cell division.

Animals↗
PubMed1981

Metabolic alterations in the synoviocytes in chronically inflamed knee joints in immune arthritis in the rabbit: comparison with rheumatoid arthritis.

The metabolism of the synovial lining cells of the normal and chronically inflamed joints of rabbits, in the Dumonde and Glynn model of rheumatoid arthritis, has been examined by quantitative cytochemistry. Significant alterations in metabolic activity were found in the synovial lining cells of the chronically inflamed joints. These alterations in metabolic activity closely resemble the pattern of metabolic changes found in human synovial lining cells in rheumatoid arthritis.

Animals↗
PubMed1981

Collagen-induced arthritis in the rat: modification of immune and arthritic responses by free collagen and immune anti-collagen antiserum.

Inbred Wistar strain rats developed a polyarthritic disease when injected intradermally with Freund's incomplete adjuvant (FIA) containing porcine or bovine type II collagen (CII). In contrast, neither allogeneic rat CII nor porcine proteoglycan monomer were arthritogenic, although both were, to some extent, immunogenic. Animals passively transfused with immune serum containing anti-CII antibodies did not develop arthritis and showed greatly reduced anti-CII humoral immune responses (measured by an enzyme-linked immunosorbent assay) when the serum was administered at the time of and subsequent to challenge with arthritogenic porcine CII. Similarly, the intravenous injection of animals sequentially with 100 microgram soluble CII and 1 ml immune anti-CII antiserum, 9 and 8 days respectively before challenge with arthritogenic CII, abrogated the arthritic response and depressed the humoral anti-porcine CII and anti-rat CII antibody titres more than tenfold. It is concluded that the immune status of the recipient rats with respect to CII is crucially important in determining the nature of the immune and arthritic response to CII appropriately administered in FIA.

Animals↗
PubMed1980

DNA synthesis in human rheumatoid and nonrheumatoid synovial lining.

The DNA content per nucleus has been measured in the lining cells of 12 specimens of rheumatoid and 12 of nonrheumatoid synovial tissue. Optimal conditions for this reaction on these cells have been defined, and an index of DNA synthesis has been applied to give a quantitative measure of the degree of synthesis. This has given evidence of some DNA synthesis in both types of synoviocytes, compatible with the amount found in a slowly self-replacing tissue. There was no difference in the amount of synthesis in the rheumatoid and nonrheumatoid synoviocytes.

Adolescent↗
PubMed1980

Cytochemical bioassay of parathyroid hormone: characteristics of the assay and analysis of circulating hormonal forms.

A cytochemical bioassay for parathyroid hormone (PTH) was used for the characterization of the biological activity of circulating forms of the hormone. PTH-stimulated glucose-6-phosphate dehydrogenase activity in distal convoluted tubule cells was quantitated by integrating microdensitometry and the response to native bovine (b)PTH(1-84) was found to be linear between graded doses of hormone from 5 fg/ml to 5 pg/ml. Synthetic bPTH(1-34) and human (h)PTH(1-34) elicited a parallel and equimolar response; however calcitonin, ACTH, glucagon, epinephrine, vasopressin, and insulin failed to significantly stimulate the enzyme in doses up to 100,000 times greater than the lowest concentration of bPTH used. The assay was capable of distinguishing hormonal activity in normal, hypoparathyroid, and hyperparathyroid human plasma. After gel chromatography, bioactivity in plasma of hyperparathyroid patients with skeletal disease but normal kidney function coeluted mainly with bPTH(1-84), whereas bioactivity in plasma of hyperparathyroid patients with skeletal disease but severe uremia coeluted in approximately equivalent amounts with bPTH(1-84) and hPTH(1-34). Despite the abundance of small molecular-weight bioactivity in the peripheral circulation in uremia, approximately 85% of the bioactivity in the parathyroid venous effluent coeluted with bPTH(1-84). The results therefore demonstrate the sensitivity and specificity of the assay for PTH and its utility in measuring the hormone in human parathyroid disorders. The results furthermore demonstrate the importance of entities cochromatographing with bPTH(1-84) in comprising the circulating bioactive hormone in hyperparathyroidism, and support the concept of a biological role for smaller forms of PTH, at least in chronic renal failure.

Animals↗
PubMed1980

Thyrotropin binding to rat thyroid membranes: reduced capacity associated with goitrogenesis.

To investigate a possible role of TSH in the regulation of its own receptor, a sensitive assay of [125I]TSH tropin binding to rat thyroid membranes was used. With 1 mM MgCl2 in the buffer, Scatchard analysis of displacement of TSH gave a curvilinear plot with a high affinity, low capacity (K1, 3.4 nM; Q1, 3.1 pmol/microgram) and a low affinity, high capacity binding site (K2, 0.54 microM; Q2, 1.2 X 0.1 nmol/microgram). Feeding rats propylthiouracil led to a decrease in [125I]TSH binding (expressed either per U protein or per wet wt of tissue) that was related to the duration of treatment. Evaluation by Scatchard analysis showed that this was due to a loss of binding sites, e.g. a 50-60% decrease after 1 month of propylthiouracil treatment; affinity was actually slightly increased in the goitrous tissue. This change in the number of TSH-binding sites was readily reversed in association with the suppression of TSH in vivo either by injections of T3 for 3 days or more by feeding a normal diet for 1 month. Thus, the data are compatible with TSH, that is in high concentration in the serum of rats fed propylthiouracil, exerting a downregulatory influence on its own receptors.

Adenylyl Cyclases↗
PubMed1979

Glycolytic activity in human synovial lining cells in rheumatoid arthritis.

It was conceivable that the previously reported elevated pentose-shunt activity in human rheumatoid synoviocytes could be at the expense of glycolytic activity. To test this possibility the activities of glyceraldehyde 3-phosphate and lactate dehydrogenase, the two dehydrogenase enzymes of the latter pathway, have been investigated in the synovial lining cells in fresh sections of nonrheumatoid and rheumatoid synovial tissue. To measure the activity solely in the lining cells, apart from that in underlying infiltrating cells, quantitative cytochemical reactions have been used; the activities were measured by microdensitometry. The results showed highly and significantly increased activity of both enzymes in the rheumatoid cells. Increased activity was also found in synoviocytes in nonrheumatoid synovial tissue after trauma, so that the increased activity of these enzymes is not characteristic of the rheumatoid condition. However, the results indicate that the increased pentose shunt activity in rheumatoid synovial lining cells is not at the expense of glycolytic activity but may be part of an enhanced potential for utilising glucose 6-phosphate in these cells.

Adolescent↗