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Biomedical subjects

G Franz

Publications and source records attributed to G Franz.

At least 19 recordsLinked to original sources
PubMed1992

Pythium aphanidermatum: culture, cell-wall composition, and isolation and structure of antitumour storage and solubilised cell-wall (1----3),(1----6)-beta-D-glucans.

Under optimal conditions for the culture of the fungus Phytium aphanidermatum, no polysaccharides were excreted into the medium. The mycelium contained up to 38% of a slightly branched, storage (1----3),(1----6)-beta-D-glucan with a MW of 20,000. The cell-wall polysaccharides of the mycelium comprised 18% of cellulose and 82% of (1----3),(1----6)-beta-D-glucans. Of the non-cellulosic glucans, approximately 33% could be solubilised by extraction with water at 121 degrees, and they had a MW of 10,000, were highly branched, and contained 6% of (1----6) linkages. Treatment of the cell wall with 0.1 M trifluoroacetic acid released approximately 50% of the non-cellulosic glucans. The acid-soluble cell-wall (1----3),-(1----6)-beta-D-glucans of lower MW (6000) were still highly branched and contained 14% of (1----6) and 8% of (1----4) linkages. The storage glucan and the hot-water-soluble cell-wall glucan exhibited strong activity against the Sarcoma 180 in CD-1 mice, whereas the acid-soluble cell-wall glucans were inactive. The hot-water-soluble cell-wall glucan was also active against the DBA/2-MC.SC-1 fibrosarcoma in DBA/2 mice.

Animals↗
PubMed1992

Synthesis and antitumour activity of derivatives of curdlan and lichenan branched at C-6.

Derivatives of curdlan and lichenan, linear (1----3)-beta-D- and (1----3/1----4)-beta-D-glucans, respectively, have been synthesised having alpha-L-arabinofuranosyl, alpha-L-rhamnosyl, beta-D-glucosyl, and beta-gentiobiosyl side chains attached at positions 6. These water-soluble derivatives, obtained by condensation of the 2,4- and 2,4-/2,3-di-O-phenylcarbamoyl derivatives of curdlan and lichenan, respectively, with appropriate ortho esters followed by saponification, were characterised by methylation analysis, g.p.c., and interaction with Congo Red. The curdlan derivatives and the lichenan derivative with few glucosyl branches were active against the Sarcoma 180.

Animals↗
PubMed1992

Synthesis and antitumour activity of sulfoalkyl derivatives of curdlan and lichenan.

2-Sulfoethyl, 3-sulfopropyl, and 4-sulfobutyl derivatives of the (1----3)-beta-D-glucan curdlan and the (1----3/1----4)-beta-D-glucan lichenan have been synthesised. The substituents are located mainly at positions 6. The curdlan derivatives strongly inhibited the growth of the Sarcoma 180 tumour, whereas the lichenan derivatives were inactive, indicating that a (1----3)-linked beta-D-glucan backbone is essential for activity.

Animals↗
PubMed1992

Transcriptional regulation of a seed-specific carrot gene, DC8.

Many late embryogenesis abundant (Lea) protein genes in plants are regulated by abscisic acid (ABA). The RNA level of a carrot gene, DC8, increases in response to ABA in developing seeds. However, DC8 cannot be induced by ABA in adult tissues. We used chimeric genes made of various DC8 promoter fragments fused to beta-glucuronidase (GUS) to analyze the transcriptional regulation of DC8. DC8:GUS expression was measured in electroporated carrot protoplasts and in stably transformed carrots. The region of the DC8 promoter from -170 to -51 contained ABA-responsive sequences that required a 5' upstream region for high levels of expression in embryogenic callus protoplasts. 505 bp of the DC8 promoter conferred GUS expression in stably transformed somatic and zygotic embryos. DC8:GUS was expressed only in tissues formed in the seed. This includes cells in the embryo, the endosperm and the germinating seedlings. Gel retardation and competition experiments were performed to analyze the embryo nuclear protein-DNA binding activities in vitro. No binding activity was detected on the putative ABA-responsive region; however the 5' upstream regions located between -505 and -301 interacted with embryo nuclear factors. An additional site of DNA-protein interaction was located between positions -32 and +178. The nuclear proteins that bind these sequences were found in the embryo nuclei only, not in the nuclei from leaves or roots.

Abscisic Acid↗
PubMed1992

Antitumour and immunological activity of a beta 1----3/1----6 glucan from Glomerella cingulata.

The in vivo antitumour activity of a beta 1----3/1----6 glucan from the fungus Glomerella cingulata was investigated in vivo. The glucan exhibited a strong inhibition of tumour growth of the allogeneic Sarcoma-180 as well as the syngeneic DBA/2-MC.SC-1 fibrosarcoma with inhibition ratios up to 100%. Against the hormone sensitive Noble-Nb-R prostate carcinoma the glucan alone showed a moderate antitumour effect, whereas in combination with diethylstilbestrol an almost complete regression of the tumour could be achieved. It could be demonstrated that a highly ordered structure of the glucan is not essential for the antitumour activity. Since the glucan expressed no direct cytotoxic effects, the immunomodulating activity was investigated in vitro in order to get an indication for a possible mode of action. In the lymphocyte transformation assay the glucan at a dose of 100 micrograms/ml caused a fourfold increase in the proliferation of murine spleen lymphocytes. Moreover, the glucan stimulated the phagocytosis of zymosan by bone marrow macrophages up to 100%. However, the glucan was not able to render macrophages cytotoxic against P-815 mastocytoma cells.

Animals↗
PubMed1992

Antitumor activity of cell wall beta-1,3/1,6-glucans from Phytophthora species.

From the cell walls of various Phytophthora species (Oomycetes) different water-soluble beta-1,3/1,6-glucans were isolated and characterized. The glucans with relative molecular masses between 13 and 50 kd exhibited varying degrees of branching in the beta-1,3-linked glucan backbone ranging from 14 to 50%. The dose-dependent antitumor activity of the glucans against allogeneic sarcoma-180 was investigated. It could be demonstrated that beta-1,3/1,6-glucans with relative molecular masses below 50 kd can exhibit a prominent antitumor activity (inhibition rate up to 99%), being comparable to that of the high relative molecular mass (450 kd) beta-1,3/1,6-glucans. Biological activity of the glucans could be shown to be correlated with a low degree of branching. The most potent glucan with a degree of branching of 14% also was active against the syngeneic DBA/2-MC.SC-1 fibrosarcoma (inhibition rate up to 90%) and in combination with a suboptimum dose of diethylstilbestrol against Nobel-Nb prostate carcinoma (inhibition rate up to 90%).

Animals↗
PubMed1992

Chemical structure and biological activity of polysaccharides from Hibiscus sabdariffa.

Three water-soluble polysaccharides have been isolated from flower buds of Hibiscus sabdariffa L. (HIB 1,2,3). The neutral polysaccharides (HIB 1 and 2) are composed of arabinans and arabinogalactans of low relative molecular mass. The major fraction was investigated by methylation analysis, pectinase-treatment, mild acid hydrolysis and NMR studies, and it was shown to be a pectin-like molecule (Mr = 10(5)d). The main chain is composed of alpha-1,4-linked GalA (24% methyl-esterified) and alpha-1,2-linked Rha. Side chains are built of Gal and Ara and are connected to the main chain via C-4 of every third Rha. Its structure seems to be different from polysaccharide structures described in other species of the Hibiscus genus and the Malvaceae family. All fractions were assayed for possible immune-modulating effects. All fractions showed some activity, but the main acidic fraction was contaminated with lipopolysaccharide, and therefore its shown activity has to be discussed carefully.

Animals↗
PubMed1992

Synthesis of laminarin sulfates with anticoagulant activity.

Laminarin sulfates were synthesized without significant degradation of the genuine laminarin chain using SO3/pyridine complex as a sulfation reagent. 6 derivatives with a degree of sulfation (d.s.) ranging from 0.30 to 2.26 could be obtained. According to methylation analysis the C-6-OH-groups of the glucose molecules were preferentially substituted, followed by the OH-groups at C-2 and C-4. The derivatives Lam S1 (d.s. = 0.30) and Lam S2 (d.s. = 0.64) showed no activity in the blood coagulation tests. With increasing d.s. the anticoagulant activity increased until an optimum d.s. of 1.49. Anticoagulant laminarin sulfates showed significant activity in the activated partial thromboplastin time (APTT) test but were less active in the anti-Factor Xa as well as anti-Factor IIa assay. Therefore, the anticoagulant activity of the synthesized laminarin sulfates is due to the interaction at an early stage of the coagulation cascade and neither to a direct inhibition of Factor Xa and IIa nor to an indirect effect mediated by antithrombin III.

Anticoagulants↗
PubMed1992

Immunological and antitumor effects of coumarin and some derivatives.

Coumarin and its 4-OH and 7-OH derivatives, as well as o-, m- and p-coumaric acid were tested against P-815 and P-388 tumor cells in vitro. In addition, the compounds were investigated in various in vitro immunological test systems and genuine coumarin was tested furthermore against the Sarcoma-180 in CD1 mice. In vivo, coumarin showed only a moderate antitumor effect against the allogeneic Sarcoma-180 at concentrations of 10 and 40 mg/kg, with inhibition rates of 49 and 60%, respectively. However, both concentrations were markedly toxic. In vitro all compounds were more or less cytotoxic against P-815 and P-388 tumor cell lines starting at a concentration of 100 micrograms/ml. At subtoxic concentrations (less than or equal to 10 micrograms/ml) the samples showed no mitogenic activity against murine spleen lymphocytes and PHA costimulated human peripheral blood lymphocytes. Furthermore, with the coumarin derivatives neither cytotoxic macrophages could be induced against P-815 tumor cells nor an increased release of Il-2 and TNF-alpha could be observed. Only 7-OH coumarin, in concentrations of 2 and 20 micrograms/ml, caused a strong increase in phagocytosis of 124 and 84% in both, human peripheral blood granulocytes and murine peritoneal macrophages, respectively.

Animals↗
PubMed1991

Structural investigations of glucans from cultures of Glomerella cingulata Spaulding & von Schrenck.

Methylation analysis, enzymic digestion, n.m.r. spectroscopy, and Smith degradation showed that the major extracellular polysaccharide, isolated from cultures of the fungus Glomerella cingulata, was a (1----3)-beta-D-glucan with side chains of 1-4 (1----3)-linked beta-D-glucose residues attached to position 6. A (1----6)-beta-D-glucan was produced by the fungus in small proportions. Treatment of the (1----3,1----6)-beta-D-glucan (890,315) with greater than 0.05M NaOH at greater than 150 degrees, or Me2SO-H2O with a concentration of dimethyl sulfoxide of greater than 80%, irreversibly destroyed the highly ordered structure responsible for the high viscosity of aqueous solutions. The strong shift of the lambda max of aqueous solutions of Congo Red by the degraded glucan, the fact that the mol. wt. of the original glucan was approximately 4 times higher than that of the degraded polymer, and the suppression of the n.m.r. signals for C-3 indicated that the original glucan had a highly ordered structure, probably built up from single helices.

Ascomycota↗
PubMed1991

Dumbbell meningioma of the cervico-clavicular region.

The authors are reporting on a case of a 55-year-old man with an epidural meningioma in the region from the C VII. to the Th I. segment. The tumor encircled this region, and to the front and right involved the channels through which pass the C VI, C VII. and C VIII. roots. Subdurally, no tumoral mass was found. Another part of this tumor, of the same histological architecture as the epidural cervicospinal part was found in the supraclavicular region to the right, closely connected to the arteries and nerves of this region. The authors discuss the possibility of the tumoral occurrence at this site, primarily taking into account the origin of this tumor from the cells of the outer surface of the arachnoidea, i.e. cap cells which can invade the dura, with later separation from the main arachnoidal layer. The other possibility of such dumbbell meningioma occurring at the outgoing openings of the neural paths from the spinal channel should be looked for in the remnants of the arachnoidal cells in the region of the outgoing openings. In the paper are also discussed and correlated clinico-pathological, CT and angiographic findings.

Humans↗
PubMed1991

[Polysaccharides from Nerium oleander: structure and biological activity].

A water extraction of crushed leaves of Nerium oleander yielded 2.3% of a crude polysaccharide. The main fraction (67%) represents a pectic polysaccharide mainly composed of galacturonic acid besides rhamnose, arabinose and galactose. The polysaccharide structure was characterized by NMR, mild acid- and pectinase treatment combined with GC-MS analyses. In vivo tests for a possible antitumor activity did not result in a significant action. Investigation of immunomodulating activity brought some indications for mitogenic activity and a weak macrophage-mediated cytotoxicity. Increase of phagocytosis could not be doubtlessly assigned to the polysaccharide due to the high amount of endotoxin in the homogenous fraction OLE 2.

Animals↗