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Biomedical subjects

R S Bockman

Publications and source records attributed to R S Bockman.

67 records · Page 4Linked to original sources
PubMed1980

Hypercalcaemia in malignancy.

The pathogenesis of cancer hypercalcaemia is an enigma that continues to challenge clinical investigators. Several possible mediators and pathways seem to be operating. To date, humoral and cellular mediators have been found to arise in tumour or normal tissues. The pathophysiological pathways that lead to osteolysis and hypercalcaemia are in large part determined by the biology of the specific tumour. Thus, the mechanisms that give rise to osteolysis in a metastatic breast cancer may be distinct from those that are operating in a non-metastatic lung carcinoma. The morbid consequences of excessive osteolysis and hypercalcaemia are usually similar and require prompt attention. Current research holds out the promise of identifying the agents and pathways responsible for cancer hypercalcaemia. Therapies may one day exist which arrest the specific pathophysiological processes which are operating.

Bone Neoplasms↗
PubMed1980

Stage-dependent reduction in T colony formation in Hodgkin's disease. Coincidence with monocyte synthesis of prostaglandins.

Prostaglandin synthesis and T lymphocyte colony formation have been examined in previously untreated patients with Hodgkin's disease. Mononuclear cells have been isolated from peripheral blood and spleens of these patients. Significant augmentation in prostaglandin E levels were noted in the mononuclear cell cutures from Hodgkin's disease patients compared with controls (1.64 +/- 0.29 vs. 0.39 +/- 0.09 ng/10(6) cells, P < 0.005). Measured prostaglandin E levels increased with advancing stage of disease. Virtually all of the prostaglandins were synthesized by the adherent monocyte cell population. Prostaglandin E was the major product. Clonal expansion of a T lymphocyte precursor cell, which gives rise to colonies > 50 cells, was determined by a layered soft agar method. T colony formation was significantly reduced in patients with stage II, III, and IV disease. There were progressively reduced colony numbers seen with advancing stage of disease (609 +/- 209, 416 +/- 158, 207 +/- 58 compared with normals 2,274 +/- 360 colonies/10(6) cells plated; P < 0.005). The addition of inhibitors of endogenous prostaglandin synthesis resulted in significant augmentation of T colony number. However, a consistent relative decrease in T colony number was seen even when endogenous prostaglandin E synthesis was blocked. It would appear that both the prostaglandin-dependent and independent T colony precursor cells are lost with progressive stage of disease. A causative role of augmented prostaglandin synthesis in this stage-dependent reduction of T colony formation could not be established.

Adolescent↗
PubMed1979

Induction of prostaglandin E synthesis in normal and neoplastic macrophages: role for colony-stimulating factor(s) distinct from effects on myeloid progenitor cell proliferation.

The biosynthesis of prostaglandin E (PGE) by normal and neoplastic macrophages is intrinsically linked to their synthesis of, and exposure to, myeloid colony-stimulating factors (CS-factors). The defect in responsiveness to endotoxin lipopolysaccharide (LPS) by macrophages from C3H/HeJ mice extends equally to the synthesis of CS-factor and PGE. However, C3H/HeJ macrophages can be stimulated to synthesize PGE by treatment with agents other than LPS [zymosan, tuberculin purified protein derivative, concanavalin A, poly(I).poly(C)], which also stimulate CS-factor production, or by the addition of various preparations of soluble CS-factor. In peritoneal wash preparations, constitutive PGE synthesis occurred in rapidly sedimenting macrophage cells, whereas constitutive CS-factor production and inducible PGE synthesis occurred in slower sedimenting adherent cells. A similar functional heterogeneity in CS-factor and PGE production was found in neoplastic macrophagae cell lines. The association of elevated CS-factor levels and PGE synthesis by macrophages suggests a role for CS-factor in many of the physiological responses heretofore associated with elevated tissue levels of the E type prostaglandins.

Animals↗
PubMed1979

Prostaglandin E inhibition of T-lymphocyte colony formation: a possible mechanism of monocyte modulation of clonal expansion.

Prostaglandin and monocyte modulation of a T-lymphocyte cell capable of undergoing clonal expansion was studied. Circulating human mononuclear cells were isolated by density centrifugation. After 24 h in culture with phytohemagglutinin present, the cells were mixed with 0.3% agar and overlayed onto a 0.5% agar layer that contained media and phytohemagglutinin. At day 6, colonies that contained greater than 50 cells were counted. These colonies represented clonal prolifertion of a phytohemagglutinin-responsive T-lymphocyte precursor. This responder cell accounted for less than 0.3% of the starting cell population. Colonies were comprised of cells which, when isolated, formed E rosettes. These colony cells could be shown to have helper or suppressor function as measured by their ability to promote or inhibit immunoglobulin synthesis. By these latter criteria the colony cells were considered to be mature T lymphocytes. The addition of prostaglandin E to the cultures demonstrated a linear, r = 0.82, dose-dependent inhibition of colony formation with a 50% point of inhibition (I50) = 0.18 muM. Low numbers of normal monocytes when added to the cultures mimicked the effect of synthetic prostaglandin E2. A highly significant correlation could be shown for endogenous prostaglandin E levels and colony counts. It appears that monocytes through their synthesis of prostaglandin E2 can restrict the clonal expansion of a circulating T-lymphocyte precursor.

Adult↗
PubMed1978

Limitation of excessive myelopoiesis by the intrinsic modulation of macrophage-derived prostaglandin E.

The clonal proliferation of the committed granulocyte-macrophage stem cell is controlled by a balance between mutually opposing factors, colony stimulating factor and prostaglandin E, both of monocyte-macrophage derivation. Increases beyond a critical concentration of colony stimulating factor within the local milieu of the mononuclear phagocyte induces the coincident elaboration of prostaglandin E, a self-regulated response which serves to limit the unopposed humoral stimulation of myelopoiesis.

Animals↗
PubMed1967

Studies on the proteolytic activity of gamma-globulin preparations.

1. The proteolytic activities of several gamma-globulin preparations were tested. These included sulphate-precipitated human and bovine preparations and human and bovine Cohn fraction II preparations as well as purified gamma-globulin preparations. Up to 14mg. of diffusible peptides and glycopeptides/g. of gamma-globulin was liberated after dialysis and up to 10mg. of peptides/g. after incubation and trichloroacetic acid precipitation, as products of the degradation process in incubated gamma-globulin. 2. in-Aminohexanoic acid and p-chloromercuribenzoic acid, as well as heating at 60 degrees for 40min., were shown to inhibit strongly these proteolytic activities. Streptokinase was shown to activate strongly the proteolytic activity of all the human preparations (sulphate-precipitated, Cohn fraction II, and purified gamma-globulin). 3. Two distinct pH optima were shown for human and bovine gamma-globulin preparations: one at pH8, the other at pH3.8 (the latter activity could be demonstrated only in the presence of cysteine). 4. Both (131)I-labelled human Cohn fraction II and bovine fibrinogen were attacked by a sulphate-precipitated preparation of gamma-globulin. Of the synthetic substrates tested toluene-p-sulphonyl-l-arginine methyl ester was hydrolysed by both the sulphate-precipitated and Cohn fraction II preparations, as was benzoyl-l-arginine amide at pH5, but only in the presence of cysteine. 5. These data are interpreted to indicate that at least two enzymes are present in gamma-globulin preparations, one being similar to the plasmin system, the other similar to cathepsin B.

Acids↗