A Versatile Transfection Assay System to Evaluate the Biological Effects of Diverse Industrial Chemicals

The biological effects of short-wave ultraviolet light has generally been described in terms of changes in cell growth or survival rates and production of chromosomal aberrations. Ultrastructural changes following exposure of cells to ultraviolet light, particularly at 265 nm, have not been reported.We have developed a means of irradiating populations of cells grown in vitro to a monochromatic ultraviolet laser beam at a wavelength of 265 nm based on the method of Johnson. The cell types studies were: i) WI-38, a human diploid fibroblast; ii) CMP, a human adenocarcinoma cell line; and iii) Don C-II, a Chinese hamster fibroblast cell strain. The cells were exposed either in situ or in suspension to the ultraviolet laser (UVL) beam. Irradiated cell populations were studied either "immediately" or following growth for 1-8 days after irradiation.Differential sensitivity, as measured by survival rates were observed in the three cell types studied. Pattern of ultrastructural changes were also different in the three cell types.

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Genomic analysis of C-type lectins

Biochemical Society Symposium ◽

10.1042/bss0690059 ◽

2002 ◽

Vol 69 ◽

pp. 59-72 ◽

Cited By ~ 85

Author(s):

Kurt Drickamer ◽

Andrew J. Fadden

Keyword(s):

Biological Effects ◽

Cell Signalling ◽

Genomic Analysis ◽

Binding Activity ◽

Immunoglobulin Superfamily ◽

Carbohydrate Binding ◽

Carbohydrate Recognition ◽

Calcium Dependent ◽

Binding Domains ◽

Carbohydrate Recognition Domains

Many biological effects of complex carbohydrates are mediated by lectins that contain discrete carbohydrate-recognition domains. At least seven structurally distinct families of carbohydrate-recognition domains are found in lectins that are involved in intracellular trafficking, cell adhesion, cell–cell signalling, glycoprotein turnover and innate immunity. Genome-wide analysis of potential carbohydrate-binding domains is now possible. Two classes of intracellular lectins involved in glycoprotein trafficking are present in yeast, model invertebrates and vertebrates, and two other classes are present in vertebrates only. At the cell surface, calcium-dependent (C-type) lectins and galectins are found in model invertebrates and vertebrates, but not in yeast; immunoglobulin superfamily (I-type) lectins are only found in vertebrates. The evolutionary appearance of different classes of sugar-binding protein modules parallels a development towards more complex oligosaccharides that provide increased opportunities for specific recognition phenomena. An overall picture of the lectins present in humans can now be proposed. Based on our knowledge of the structures of several of the C-type carbohydrate-recognition domains, it is possible to suggest ligand-binding activity that may be associated with novel C-type lectin-like domains identified in a systematic screen of the human genome. Further analysis of the sequences of proteins containing these domains can be used as a basis for proposing potential biological functions.

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Biological effects and biochemical events triggered by interaction of inactivated HIV-1 virions with T-cell subsets

Immunology Letters ◽

10.1016/s0165-2478(97)86925-8 ◽

1997 ◽

Vol 56 (1-3) ◽

pp. 23

Author(s):

L Racioppi

Keyword(s):

T Cell ◽

Biological Effects ◽

T Cell Subsets ◽

Hiv 1

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The Significance of TFPI in Clotting Assays – Gomparison and Combination with other Anticoagulants

Thrombosis and Haemostasis ◽

10.1055/s-0038-1649603 ◽

1993 ◽

Vol 70 (03) ◽

pp. 448-453 ◽

Cited By ~ 12

Author(s):

Ole Nordfang ◽

Hanne I Kristensen ◽

Sanne Valentin ◽

Per Østergaard ◽

Johnny Wadt

Keyword(s):

Tissue Factor ◽

Tissue Factor Pathway Inhibitor ◽

Antithrombin Iii ◽

Anticoagulant Activity ◽

Assay System ◽

Thrombin Inhibitor ◽

Clotting Time ◽

Normal Plasma ◽

Tissue Factor Pathway ◽

Plasma Heparin

SummaryThe anticoagulant activities of Tissue Factor Pathway Inhibitor (TFPI), heparin and hirudin were compared in intrinsic (APTT) and extrinsic (PT) activated clotting assays. In contrast to the thrombin inhibitor hirudin, heparin was 10 fold more potent in the APTT assay than in the PT assay, indicating that inhibition of intrinsic activation is important for the anticoagulant activity of heparin as measured in an APTT assay. TFPI was most potent in the PT assay and the effect of TFPI was most pronounced in the presence of other anticoagulants (heparin and hirudin). The activities of the two natural anticoagulants antithrombin III (ATIII) and TFPI were compared in a PT assay with very dilute tissue factor. In this assay system TFPI in normal plasma affected the clotting time more than ATIII in the plasma. However, when heparin was added ATIII was the major anticoagulant, but profound Prolongation of the clotting time was only seen when TFPI was also added. In an ATIII deficient plasma heparin did not augment the effect of TFPI, showing that the increased effect of TFPI in the presence of heparin is dependent on the anticoagulant activity of ATIII/heparin. The effect of TFPI at prolonged clotting times was also illustrated by the significant effect of blocking TFPI in the plasma from warfarin-treated patients. Thus TFPI is a major anticoagulant in normal plasma and the effect of TFPI is especially seen at prolonged clotting times.

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A Comparative Ex Vivo Study of Plasminogen Activators and Proteases for Fibrinolytic Activity and Side Effects in Rabbits

Thrombosis and Haemostasis ◽

10.1055/s-0038-1649213 ◽

1977 ◽

Vol 37 (01) ◽

pp. 154-161 ◽

Cited By ~ 1

Author(s):

B. A Janik ◽

S. E Papaioannou

Keyword(s):

Side Effects ◽

Effective Dose ◽

Fibrinolytic Activity ◽

Ex Vivo ◽

Plasminogen Activators ◽

Assay System ◽

Coagulation Parameters ◽

Ex Vivo Assay

SummaryUrokinase, streptokinase, Brinase, trypsin, and SN 687, a bacterial exoprotease, have been evaluated in an ex vivo assay system. These enzymes were injected into rabbits and the fibrinolytic activity as well as other coagulation parameters were measured by in vitro techniques. Dose-response correlations have been made using the euglobulin lysis time as a measure of fibrinolytic activity and the 50% effective dose has been determined for each enzyme. Loading doses, equal to four times the 50% effective dose, were administered to monitor potential toxicity revealing that Brinase, trypsin, and SN 687 were very toxic at this concentration.Having established the 50% effective dose for each enzyme, further testing was conducted where relevant fibrinolytic and coagulation parameters were measured for up to two days following a 50% effective dose bolus injection of each enzyme. Our results have demonstrated that urokinase and streptokinase are plasminogen activators specifically activating the rabbit fibrinolytic system while Brinase, trypsin and SN 687 increase the general proteolytic activity in vivo.The advantages of this ex vivo assay system for evaluating relative fibrinolytic potencies and side effects for plasminogen activators and fibrinolytic proteases have been discussed.

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Quantitative Determination of Plasminogen

Thrombosis and Haemostasis ◽

10.1055/s-0038-1654134 ◽

1970 ◽

Vol 23 (02) ◽

pp. 191-201 ◽

Cited By ~ 2

Author(s):

H. D Bruhn ◽

L Müller ◽

F Duckert

Keyword(s):

Quantitative Determination ◽

Plasminogen Activator ◽

Assay System ◽

Two Stage ◽

System Activation ◽

Frozen Plasma

SummaryA modification of the caseinolytic assay for plasminogen is described. This assay system is characterized by the following features :1. Urokinase is used as activator achieving a complete activation of the plasminogen whereas with streptokinase caseinolytically inactive plasminogen-activator complexes are formed.2. All incubation times are reduced to the minimum which is still compatible with accuracy.3. Results are expressed in percent of a standard of ten normal plasmas.4. In this two-stage assay-system (activation of plasminogen to plasmin, digestion of casein by plasmin) both stages proceed simultaneously in the same system, thus the plasmin formed is stabilized “in statu nascendi” by the casein.5. Several conditions (stability of plasminogen in frozen plasma, use of anticoagulants, reproducibility) are defined.

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The mechanism for the primary biological effects of ionizing radiation

Uspekhi Fizicheskih Nauk ◽

10.3367/ufnr.0176.200605b.0487 ◽

2006 ◽

Vol 176 (5) ◽

pp. 487 ◽

Cited By ~ 6

Author(s):

V.M. Byakov ◽

S.V. Stepanov

Keyword(s):

Ionizing Radiation ◽

Biological Effects

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INFLUENCE OF SPECIFIC ANTISERUM ON BIOLOGICAL EFFECTS OF HUMAN GONADOTROPHINS

Acta Endocrinologica ◽

10.1530/acta.0.056s122 ◽

1967 ◽

Vol 56 (1_Suppl) ◽

pp. S122

Author(s):

P.-J. Czygan ◽

D. Krebs ◽

F. Lehmann ◽

G. Bettendorf

Keyword(s):

Biological Effects ◽

Specific Antiserum

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SPECIAL PROBLEMS IN TOXICITY TESTING OF LONG ACTING DEPOT CONTRACEPTIVES

Acta Endocrinologica ◽

10.1530/acta.0.075s315 ◽

1974 ◽

Vol 77 (1_Suppla) ◽

pp. S315-S354 ◽

Cited By ~ 4

Author(s):

F. Neumann ◽

R. von Berswordt-Wallrabe ◽

W. Elger ◽

K.-J. Gräf ◽

S. H. Hasan ◽

...

Keyword(s):

Biological Effects ◽

Histological Finding ◽

Toxicity Testing ◽

Prolactin Secretion ◽

List Type ◽

Human Species ◽

Prolactin Plasma Level ◽

Human Use ◽

Long Acting ◽

Reproductive Processes

ABSTRACT Two types of so-called "depot contraceptives", long-acting steroids which are of interest for human use, were studied in animals. Norethisterone oenanthate, mainly gestagenic in the human and other species, turned out to be predominantly oestrogenic in rats. This oestrogenicity caused indirectly, via an enhanced hypophysial prolactin secretion, the well-known hypophysial and mammary tumours in rats. Another synthetic gestagen, 4,6-dichloro- 17- acetoxy- 16α-methyl-4,6-pregnadiene-3,20-dione, which might be considered in its biological actions similar to preparations containing chlormadinone acetate or medroxy-progesterone acetate, induced no signs of oestrogenicity in dogs. It is surmised that its gestagenic influence indirectly, and probaby, via an enhanced hypophysial prolactin secretion caused "mammary nodules" in this "non-rodent" species. These studies have born out mainly two facts: A synthetic steroid, norethisterone oenanthate, exerted different biological effects in different species: it was a gestagen in the rabbit, whereas in rats, its predominant influence was oestrogenic. The hypophysial prolactin secretion was enhanced in various species by different mechanisms: in rats, the oestrogenicity caused an increased prolactin plasma level, whereas in dogs, a gestagen with obviously no inherent oestrogenicity, 4,6-dichloro-17-acetoxy-16α-methyl-4,6-pregnadiene-3,20-dione, converted the histological appearance of the anterior pituitary into a condition with a greatly increased number of eosinophils. This histological finding was interpreted as an indicator for a hypersecretion of prolactin. Hence, animal work with "gestagens" has only limited predictive value with respect to their possible effects in the human species. Therefore, inflexible recommendations are not helpful in solving the safety problem of long-acting steroids which affect primarily reproductive processes.

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