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Biomedical subjects

G H Werner

Publications and source records attributed to G H Werner.

At least 19 recordsLinked to original sources
PubMed1992

Identical photosensitizing activities of a sulfonated aluminium phthalocyanine on human erythroleukemia cell lines susceptible or resistant to the cytotoxic activity of doxorubicin.

In this paper we report that a human erythroleukemia cell line made 100 times more resistant than the parental line to the cytostatic activity of doxorubicin and spontaneously 500-1000 times more resistant to the cytostatic activity of an unrelated drug, namely taxol, exhibits on the other hand unchanged susceptibility to the photosensitizing activity of a sulfonated phthalocyanine.

Antineoplastic Agents↗
PubMed1992

[Chemoprophylaxis and chemotherapy of common colds caused by rhinoviruses: overview and outlook].

Rhinoviruses are the main etiologic agents of infectious common colds, which represent about 40% of the acute respiratory infections in man. The antigenic diversity of rhinoviruses precludes any prevention by vaccination. Within the last 20 years, efforts have therefore concentrated on chemoprophylaxis or chemotherapy with antiviral agents. Interferons (alpha and beta) administered intranasally at high doses, exerted a significant prophylactic activity in volunteers inoculated with rhinoviruses or in the course of epidemics in families. By contrast, the therapeutic activity of interferons is almost nonexistent, which greatly limits their practical interest. Various synthetic chemicals exert a marked and selective inhibitory effect on the replication of various serotypes of rhinoviruses in cell cultures. In the absence of an animal model of rhinovirus infection, in vivo studies of these molecules have been performed in human volunteers, chiefly at the Common Cold Research Unit in Salisbury (Great Britain). 3 synthetic compounds (an imidazothiazole, a benzimidazole derivative and a piperazinyl-pyridazine) have exerted a significant prophylactic activity, especially marked with the latter. None of these compounds, however, was active when administered after the infectious challenge. The search for selective anti-rhinovirus compounds is still going on; it will probably be facilitated through a combination of structural studies of rhinovirus capsids (or of their cellular receptors) with computer-assisted design of synthetic molecules. The recent observation of the influence of psychological factors on the propensity of rhinovirus-infected subjects to develop clinically apparent common cold must be taken into account in future studies.

Antiviral Agents↗
PubMed1987

Fluoride effects on 31P NMR spectra of macrophages.

31P High resolution nuclear magnetic resonance studies have been carried out on the P388D1 tumoral cell line and the BCG elicited alveolar rabbit macrophages both in sedimented cells and in perfused agarose-embedded cells. When the cells were sufficiently oxygenated, the phosphorylated sugars and ATP concentrations attained high levels. The intensity of the peak representing phosphorylated sugars varied inversely with ATP level when macrophagic cells were treated by NaF. The identities of the phosphorylated sugars were revealed by 1H and 31P NMR studies of the P 388D1 cells perchloric extracts.

Adenosine Triphosphate↗
PubMed1987

Natural and synthetic peptides (other than neuropeptides) endowed with immunomodulating activities.

A large number of peptides, in most cases of low or relatively low molecular weight, exert immunomodulating activities, i.e., they interact in vitro with various cell populations of the immune system and, in vivo, enhance or depress, according to the case, cell-mediated and humoral immune functions. Immunomodulating peptides include glycopeptides from the bacterial cell wall, natural acyloligopeptide ciclosporin, peptidic hormones from the thytide cyclosporine, peptidic hormones from the thymus, peptidic fragments of immunoglobulins and other plasma proteins, as well as peptides isolated from food proteins. An amazing diversity of structure exists among the various immunomodulating peptides. The molecular mechanisms of interaction between these peptides and the cells of the immune system remain, in most cases, to be elucidated. Possibilities of therapeutic applications exist for many of these immunomodulating peptides: one of them (ciclosporin) is widely used as an immunosuppressive drug, several others (glycopeptides, lipopeptides, tuftsin, thymic peptides) are under clinical investigation as immunostimulating and/or immunorestoring agents.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1986

Synthetic immunostimulants (excluding sulfur-containing compounds).

Many different approaches have been used, over the last 15 years, for the design of potential immunostimulating drugs: Fractionation of crude natural substances (of eukaryotic or prokaryotic origin) already known to enhance immune functions, followed by chemical characterization and, in many cases, full synthesis of the active moiety: examples are provided by thymic hormones and the muramyldipeptide (MDP); Chemical modification of natural substances of known chemical structure in order to potentiate or change their biological activities or reduce their toxicity: murabutide, lipophilic MDP derivatives, lipopeptides (such as pimelautide), tuftsin analogs; Chemical synthesis (often without preconceived ideas about structure-activity relationship) of a great variety of molecules which are then screened in vitro and in vivo for immunopharmacological activity. The chemical structures and the biological profiles (in terms of possible primary cellular targets and mechanisms of immunostimulating activities) of representatives of class (b) and class (c) immunostimulants are reviewed in this paper.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1985

Studies on 44 081 R.P., a new antirhinovirus compound, in cell cultures and in volunteers.

A synthetic compound, 2-[(1,5,10,10a-tetrahydro-3H-thiazolo[3,4b]isoquinolin-3-ylidene) amino]-4-thiazoleacetic acid (S), 44 081 R.P., inhibits the multiplication of rhinoviruses in cell cultures. Of the 69 rhinovirus strains and serotypes that have been studied, 39% were inhibited at a concentration of 7 micrograms/ml, far below that which affects cellular metabolism (250 micrograms/ml). Preliminary data indicate that the compound inhibits some early events of virus replication but that some cellular functions are also involved in its mechanism of action. Despite its antiviral activity in vitro, the compound, when self-administered intranasally as a 0.2% solution to volunteers from the day before to 5 days after inoculation with a human rhinovirus strain, had no significant effect on rhinorrhea, clinical score, or laboratory evidence of infection.

Adolescent↗
PubMed1982

Synergistic activities of type I (alpha, beta) and type II (gamma) murine interferons.

Type I (alpha, beta) and type II (gamma) murine interferons are able to potentiate each other with respect to the inhibition of encephalomyocarditis (EMC) virus and of herpes simplex virus type 1 (HSV-1) multiplication in a murine cell line (DBT). Examination of two double-stranded RNA-dependent enzymes in DBT cells, the 2-5A synthetase and the 67,000 MW protein phosphokinase indicates that mixed interferon preparations act synergistically at least with respect to an increase in the activity of the former enzyme. The results obtained with gamma interferons of different origin and of different specific activity suggest that interferon itself, rather than the lymphokines present in the interferon preparations, is responsible for the synergistic effect.

2',5'-Oligoadenylate Synthetase↗
PubMed1979

[Immunostimulating and adjuvant activities of a low molecular weight lipopeptide].

From crude extracts of a Streptomyces strain exhibiting immunopotentiating effects, a tetrapeptide was isolated and its structure established as L Ala leads to D isoGlu leads to L, L Dap comes from Gly. This peptide was devoid of biological activity but its chemical coupling with lauric acid gave a substance endowed with adjuvant and immunostimulating properties. This substance and the corresponding synthetic lauroyltetrapeptide were as active in this respect as the muramyl-dipeptide, thus far considered as the minimal adjuvant-active structure of bacterial cell walls: the presence of a sugar moiety is therefore not a prerequisite for immunopotentiating activities.

Adjuvants, Immunologic↗
PubMed1978

Adjuvant and immunostimulating activities (in the absence of freund's incomplete adjuvant) of chemically modified low molecular weight mycobacterial peptidoglycans.

Relatively low molecular weight peptidoglycan fragments extracted from two strains of Mycobacterium tuberculosis var. hominis were chemically coupled with lauric acid. The fatty acid conjugates were compared with the native substances with respect to some immunopotentiating activities. In vitro, the mitogenic effect on murine spleen lymphocytes was significantly enhanced following conjugation. One of the lauric acid conjugates stimulated, upon intravenous administration in mice, the formation of antibody-producing cells in the spleen, while the native substance was devoid of such activity. In adjuvanticity tests performed in the guinea pig in the absence of mineral oil, the fatty acid conjugates generally exerted a higher adjuvant effect on antibody production or on delayed type hypersensitivity reactions than did the native preparations.

Adjuvants, Immunologic↗
PubMed1977

Adjuvant activities of chemically modified water-soluble substances from Mycobacterium tuberculosis.

Water-soluble peptidoglycan fragments extracted from the cells of two strains of Mycobacterium tuberculosis var. hominis were chemically conjugated with lauric or with palmitic acid. The coupling reaction was confirmed by physicochemical procedures. The native and the fatty acid-conjugated substances were studied for their adjuvant activity in the induction of delayed type hypersensitivity (DTH) reactions in guinea-pigs and on the production of circulating antibodies in the rabbit. Palmitic acid conjugation of one of the substances increased its adjuvanticity on DTH in the presence of mineral oil; lauric or palmitic acid conjugation rendered the substances adjuvant-active on DTH in the absence of mineral oil. Lauric acid, but not palmitic acid conjugation conferred on both substances an adjuvant activity on antibody production in the absence of mineral oil. Furthermore, lauric acid conjugation of one of the substances led to the appearance of an in vitro mitogen-like activity for murine spleen lymphocytes. In conclusion, fatty acid conjugation exerted a significant modifying effect on the immuno-potentiating activities of these peptidoglycan fragments, and such a chemical procedure may lead to the development of substances exerting a full adjuvant activity without the need of injecting them in an oily vehicle.

Adjuvants, Immunologic↗
PubMed1976

In vivo antiviral activity of D-glucosamine.

Intraperitoneal treatments with D-glucosamine, an inhibitor of the glycosylation of the viral envelope, decreased the growth rate of tumors induced in quails or in chicks by Rous sarcoma virus and increased the survival of mice inoculated with human influenza virus.

Animals↗
PubMed1976

Effect of ammonium 5-tungsto-2-antimoniate on encephalomyocarditis and vesicular stomatitis virus infections in mice.

Ammonium 5-tungsto-2-antimoniate (HPA 23) protected micr partially or completely against two strains of encephalomyocarditis (EMC) virus and one strain of vesicular stomatitis (VSV) virus. The best protective effect was obtained with EMC strain VR 129 and VSV when a single i.p. injection of HPA 23 was administered shortly before virus inoculation. Mice protected by HPA 23 against EMC strain VR129 had virus titres in the blood and brain similar to those in untreated mice. A synergism between interferon and HPA 23 was observed in mice infected with EMC VR129. Our results demonstrate the in vivo activity of HPA 23 against two lethal viral infections and suggest that, at least in mice infected with EMC, death may not be related solely to virus multiplication.

Animals↗
PubMed1975

Low molecular weight water-soluble peptidoglycans as adjuvants and immunostimulants.

The tetrasaccharide-heptapeptide (TH), when injected with mineral oil, exerted a strong adjuvant effect. It stimulated B and T cells, but did not increase the phagocytic activity of the reticulo-endothelial system. While BCG exerted significant preventive effect on the growth of sarcoma 180, leucosarcomatosis an EHRLICH ascitic tumor, TH, at the doses used, was devoid of such activity.

Adjuvants, Immunologic↗
PubMed1975

Adjuvant and immunostimulating activities of water-soluble substances extracted from Mycobacterium tuberculosis (var. hominis).

Water-soluble substances have been extracted from two strains of Mycobacterium tuberculosis var. hominis: the native hydrosoluble part (polysaccharide and peptidoglycan), a substance in which the polysaccharide moiety is less abundant than in the latter, the acetylated peptidoglycan and, finally a tetrasaccharide-heptapeptide. All four types of substances, when they were injected together with Freund's incomplete adjuvant, exerted an adjuvant effect on the production of delayed-type hypersensitivity to ovalbumin in the guinea pig and on the production of anti-influenza virus antibodies in the rabbit. Injected intravenously in the mouse, they increased the number of antibody-producing cells in the spleen and enhanced the graft versus host reaction; no effect was seen on the phagocytic activity of the reticulo-endothelial system. By contrast with wax D, the water-soluble substances were devoid of arthritis-inducing activity in the rat. Altogether, these water-soluble substances seem to be endowed with at least some of the adjuvant activities of Freund's complete adjuvant and some of the immunostimulant activities of a live Mycobacterium like BCG.

Adjuvants, Immunologic↗