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Biomedical subjects

H D Schlumberger

Publications and source records attributed to H D Schlumberger.

At least 19 recordsLinked to original sources
PubMed1997

Modern pharmaceutical biotechnology. Situation worldwide and in Germany 1995.

A variety of new diagnostics and drugs have been developed with the aid of modern biotechnology which has opened up new medical possibilities and will yield novel solutions in the future. The remarkable dynamics of the innovation process in the pharmaceutical sector is reflected by the number of drugs under development. In 1995, 771 projects were known to be in development worldwide. The leadership of North America in research and development of drugs from modern biotechnology is clearly demonstrated. Whereas the number of development recombinant DNA products remained practically constant in the triade (North America, Europe, Japan), the number of preclinical and clinical somatic gene therapy projects increased considerably in 1995 compared to 1994 in the United States and in Europe; Japan is virtually absent in this new emerging research field. In Europe, the vast majority of drugs from modern biotechnology, are developed in Great Britain, Germany, Switzerland, France, the Netherlands, and Italy. The number of gene therapy projects show a remarkable growth of more than 60% in 1995 compared with 1994; at the same time, the absolute and relative share of recombinant DNA products decreased distinctly. In Germany, about two thirds of the development of biotechnological drugs are conducted in cooperation with a foreign partner, mostly hightech companies from the United States. A variety of drugs manufactured with modern biotechnology, however, has not only provided significant medical progress and has closed therapeutic gaps but has also demonstrated considerable economic success. In 2000, further significant growth is expected especially for growth factors and cytokines.

Biotechnology↗
PubMed1989

A method for the quantitation of interleukin-2 activity.

A bioassay for the determination of interleukin-2 activity is described. We have compared the traditional method of data processing, which involves probit analysis and curve fitting, with a simpler method based on the so-called AUC (area under the curve). The latter method is readily applicable to spreadsheet software and can handle large amounts of data.

Animals↗
PubMed1988

Inhibition of HIV and virus replication by polysulphated polyxylan: HOE/BAY 946, a new antiviral compound.

Xylanpoly-(hydrogen sulphate) disodium salt with a molecular weight of about 6000 daltons (HOE/BAY 946) completely inhibited syncytium formation induced by the infection of T lymphocytes with HIV as well as viral replication at concentrations above 25 micrograms/ml. This dose was found to be inhibitory for several strains of HIV-1 and HIV-2. Low molecular weight fractions of the compound were less active against HIV, and high molecular derivatives were as active as HOE/BAY 946. A direct influence of the drug on the infectivity of the virus could not be demonstrated. The drug inhibited the reverse transcriptase of HIV. Treatment of permanently HIV-infected U937 cells resulted in a drastic reduction of virus particles released into the supernatant and points to an additional mode of action. A therapeutic effect of HOE/BAY 946 against retroviruses in vivo could be demonstrated in Friend leukaemia virus-infected mice. A clinical pilot study with the compound was started recently in Germany with AIDS patients who did not tolerate or refused to take zidovudine and with asymptomatic virus carriers.

Animals↗
PubMed1988

Monitoring of interleukin-2 receptor (IL-2R) expression in vivo and studies on an IL-2R-directed immunosuppressive therapy of active and adoptive adjuvant-induced arthritis in rats.

Recent evidence indicates that adjuvant arthritis (AA) of rats induced by complete Freund's adjuvant (CFA) is an autoimmune disease that is mediated by T cells. This report describes the distribution of activated IL-2 receptor (IL-2R)-bearing cells in spleen, popliteal lymph nodes (PLN) and blood in AA rats and in naive healthy rats using the monoclonal antibody (mAb) ART-18. It was found that in the primary lymph nodes (injected side) two peaks of elevated numbers of IL-2R-positive cells (Day 9/10 with a 40-fold increase; Day 25 with a 75-80-fold increase) occur. The PLN of the non-injected site also show an increase (30-fold) in the number of IL-2R-positive cells on Day 25. This investigation also included the monitoring of soluble IL-2R in the serum of AA rats in comparison to control sera of non-induced rats. The incidence of free IL-2R in the serum of AA rats does not completely correlate with the pattern of the distribution of receptor-bearing cells in PLN; elevated levels of IL-2R were observed at Day 9 and subsequently declined to below control levels. On Day 25, there was no correlation between IL-2R+ cells and soluble IL-2R. ART-18 was not active in suppressing the development of AA, in contrast to the complete inhibition of the passively transferred AA.

Animals↗
PubMed1987

Cultivation of Bowes melanoma cells in the Opticell system: influence of the addition of protein supplements to the serum-free medium on the production of plasminogen activator.

The influence of a protein-free and a protein-rich, supplemented serum-free medium on the production of plasminogen activator (t-PA) from Bowes melanoma cells was investigated in the Opticell culture system and compared to tissue culture flask cultures. In the presence of medium supplements metabolic activity and t-PA production were favoured in both systems. The addition of supplements was apparently more effective in the Opticell than in flask cultures, because t-PA activity obtained in the Opticell was 2-3 times higher in protein-rich medium, but 2 times lower in unsupplemented medium than in flasks. These results indicate that the protein content in a serum-free medium is important for product formation in the Opticell, and serum-free media which work at small scale in tissue culture flasks are not always suited for technical culture systems such as the Opticell but have to be adapted to them.

Biotechnology↗
PubMed1987

Monoclonal antibodies detecting plasminogen activators on the membrane of leukemic lymphoid cells of T-cell origin.

The specificities of six monoclonal antibodies produced against plasminogen activator of the human Bowes melanoma cell line are described. They have been used to detect membrane-bound plasminogen activator on cultured human lymphoid cell lines and in neoplastic human lymphocytic and myeloid cells of leukemic patients. These studies indicate that only certain phenotypic subsets of the T-cell lineage derived from patients with chronic lymphocytic leukemia or with Szezary syndrome express plasminogen activator on their surface membrane.

Animals↗
PubMed1987

Production of human monoclonal antibodies from immobilized cells in the Opticell culture system.

An EBV-transformed human B cell line, which produces monoclonal IgM antibodies, was cultured in an immobilized state on a ceramic matrix in the Opticell system. Cell growth, metabolic activity and product formation of these cells were optimized in a single semi-continuous culture of 10 inductions for 29 d. All in all, 19.5 g of IgM were harvested in 193 l of culture supernatant. The average production of IgM in the Opticell unit of 20 l was 0.7 g/d which was obtained even in serum-reduced medium (1%). Under optimal conditions IgM yields were enhanced to 1.5-2.0 g/d. These results indicate that the Opticell is a suitable system for the large scale production of monoclonal antibodies, particularly because the capacity for aeration and pumping of one Opticell unit is sufficient to control 3 growth chambers running in parallel.

Antibodies, Monoclonal↗
PubMed1985

A screening method to develop serum-free culture media for adherent cell lines.

A screening method was established to develop chemically defined, serum-free culture media for human adherent cell lines. It indicates within 2-6 months whether a certain cell line is suited for routine cultivation under serum-free conditions, and which medium supplements and surface coatings of the culture vessels the cells need for minimal demand. This method was tested with the human cell lines Bowes melanoma and prostate carcinoma 3 (PC 3).

Cell Adhesion↗
PubMed1983

Pseudo-allergic reactions to drugs and chemicals.

Drugs can interfere with the immune system in two basically different ways: (1) they may interact with the specific recognition mechanisms of the immune system and thus induce an allergic response that is specific for the offending agent; (2) drugs may exert pharmacological effects on the immune systems which result in a response that is independent of its recognition structures or they may activate effector and amplification mechanisms that are normally triggered by specific immune processes. Allergic reactions to drugs are different from reactions that exhibit the same clinical symptoms but lack the specificity of an allergic reaction to the offending agent. It has been suggested that those non-specific reactions which mimic the signs and symptoms of allergic reactions should be classified as pseudo-allergic reactions (PAR). PAR are characterized by the following properties which differentiate them from allergic reactions. (1) The symptoms of PAR are qualitatively different from the pharmacological response of a drug and are not related to adverse reactions connected with its pharmacological and toxicological profile. (2) PAR are not specific with regard to the chemical structure of the triggering agent. (3) PAR lack transferability to other subjects of the same species. (4) In contrast to the allergic reactivity, the pseudo-allergic reactivity is not acquired but genetically predetermined. (5) Pseudo-allergic reactivity is often expressed upon the first contact with an eliciting agent. PAR are thus an expression of a pharmacological interaction of drugs or their metabolites in genetically predisposed individuals.

Anaphylaxis↗
PubMed1982

A new model for investigations of T-cell functions in mice: differential immunosuppressive effects of two monoclonal anti-Thy-1.2 antibodies.

Two monoclonal anti-Thy-1.2 antibodies were investigated for their activity in eliminating T cells in vitro and in vivo. Both antibodies exert a complement-dependent cell cytotoxicity in vitro. Antibody B that belongs to the IgM class shows a 100-fold higher complement-dependent cytotoxic activity than antibody C, which is of IgG2a class. However, administration of antibody C into Balb/c mice results in the elimination of T cells as determined by the failure of different T-cell functions. Within 24 hours after administration of antibody C, the reactivity of spleen of lymph-node cells to T-cell mitogens, the antibody response to the T-cell-dependent antigen SRBC and the SRBC-induced delayed-type hypersensitivity are completely abolished. These effects are dose-dependent in a dose range of 0.1-1.0 mg Ig protein per animal and affects only T cells in the peripheral lymphoid organs. The Thy-1.2-bearing cells residing in the thymus are not impaired by the treatment of the animals with this monoclonal antibody and are able to repopulate the peripheral lymphoid organs within 30 to 60 days. Investigations into the mode of action of the removal of peripheral T cells revealed that antibody-C-coated Thy-1.2-bearing cells are rapidly phagocytosed by macrophages, while antibody-B-coated Thy-1.2-bearing cells are not. This might be the reason for the differential in-vivo activities of the two monoclonal antibodies. A model with new qualities for the study of functions and the regeneration of T cells in vivo has been established.

Animals↗
PubMed1980

The pathomechanism of acetylsalicylic acid intolerance. A hypothesis.

In a number of individuals suffering from chronic asthma or chronic urticaria, acetylsalicylic acid and structurally unrelated non-steroidal anti-inflammatory agents and other compounds, e.g. tartrazine, elicit an intolerance syndrome that mimics the signs and symptoms of an immediate-type allergic (anaphylactic) reaction. An immunological basis for this reaction could be excluded. It is assumed that the eliciting agents activate complement and that the intolerant individuals lack plasma carboxypeptidase B, that normally inactivates C3a and C5a in statu nascendi. The anaphylatoxins, if not immediately inactivated, release the endogenous mediators of the anaphylactic reaction from the tissue mast cells.

Aspirin↗
PubMed1979

[Cell kinetics in experimental rheumatoid lesions and application in antirheumatic drug research (author's transl)].

The kinetics of chronic inflammatory cellular infiltrates in antiglobulin-induced arthritis, peritonitis and subcutaneous fibrin granuloma were investigated. Only small numbers of the mononuclear cells were labeled after 3H-thymidine impulse labeling, whereas a high labeling index results after 3H-thymidine labeling of the bone marrow. It is concluded that in experimental arthritis the inflammatory so-called cellular hyperplasia consists in bone marrow derived mononuclear cells. In experimental peritonitis glucocorticoid treatment decreases the 3H-thymidine labeling indices. By means of such labeling studies the antiproliferative and antiexsudative properties of steroids were demonstrated quantitatively. Therefore we suggest to make use of experimental cell kinetics for the recognition of anti-rheumatic drugs.

Animals↗
PubMed1979

Macrophages/monocytes require cell-to-cell contact in order to regulate the growth of a murine lymphoma cell line.

The mechanism of the macrophage-regulated proliferation of the murine lymphoma cell line FIO 30 has been further investigated. It appears that the macrophage is alone in its ability to support FIO 30 growth; a macrophage-like cell line, however, is unable to provide the stimulus required by the FIO 30 cells for their proliferation. Investigations into the nature of this stimulus indicate that the serum factor pro-MaSF and a macrophage cell surface component act synergistically to support the growth of the FIO 30 cell, but only when the two cell types are in close promixity. MaSF has also been further characterized and is shown to be closely associated with serum albumin.

Animals↗
PubMed1977

Growth regulation of a murine lymphoma cell line by a 2-mercaptoethanol or macrophage-activated serum factor.

A mouse lymphoma cell line has been established that is dependent for growth on the presence of an activated serum component. This growth factor is found in an inactive form in fetal bovine serum (FBS) and can be activated by 2-mercaptoethanol and by macrophages. A factor-containing fraction can be separated from FBS by Sephadex G-100 chromatography and once activated, can be used as a substitute for whole serum in the culture medium without adverse effect on the cell growth. The significance of these findings with respect to the study of the immune response and cancer research is discussed.

Animals↗