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Relationships between the levels of binding to DNA and the carcinogenic potencies in rat nasal mucosa for three alkylating agents.

Three direct-acting carcinogens, beta-propiolactone (BPL), methylmethane sulfonate (MMS), and dimethylcarbamyl chloride (DMCC), were evaluated for their carcinogenic potencies in the nasal mucosa of rats and for their abilities to bind in vivo to rat nasal mucosal DNA. The relative carcinogenic potencies of BPL and MMS corresponded well with their overall levels of binding to nasal mucosal DNA. DMCC, however, the most potent carcinogen of the three compounds, produced the lowest level of binding to nasal mucosal DNA. These results indicate that the DNA adducts formed by DMCC in rat nasal mucosa DNA are more readily expressed as cancer than those formed by BPL or MMS.

Alkylating Agents↗

Morphological transformation of C3H/10T1/2 CL8 cells by alkylating agents.

The standard method of the C3H/10T1/2 cell transformation assay cannot adequately detect alkylating agents. A modification of the standard procedure as described by Bertram and Heidelberger using a large number of synchronized cells and high levels of toxicity was evaluated for transformation using several alkylating agents. By using this method, N-methyl-N' -nitro-N-nitrosoguanidine (MNNG), beta-propiolactone (BPL), methyl methanesulfonate (MMS), methylnitrosourea (MNU) and 1,3-propane sultone (PS) transformed these cells. However, methyl iodide (MI) failed to induce any transformed foci.

Alkylating Agents↗

A bioassay for interferon type I based on inhibition of Sendai virus growth.

The expression of type I interferons (IFNs) in eukaryotic cells represents a first line of defense against viral infection. Cells pretreated by IFNs do not support viral replication and are protected from virus-induced cell destruction. A challenge of IFN-pretreated cells with vesicular stomatitis virus (VSV) is frequently used to quantitate this cytokine because, on the one hand, the replication of VSV is highly sensitive to IFNs and, on the other hand, in unprotected cells this virus induces a rapid cytopathic effect that can readily be quantified. However, as VSV may infect humans and is known to cause severe disease in a variety of animal species, this virus must be considered a biohazard. In this paper, we describe a bioassay for bovine IFN using Sendai virus, a paramyxovirus that grows readily in MDBK cells yet is released from these cells in a non-infectious form. The sensitivity and dynamic range of this assay are similar to those of the popular VSV-based IFN assay. We demonstrate that the Sendai-virus-based IFN assay permits rapid quantitation of recombinant bovine type I IFN, and also of native type I IFNs which are present in the supernatants of monocyte-derived macrophages infected with various pathogens. In view of the possible artifacts induced by viruses in samples to be assayed for IFN activity, we evaluated several methods of virus inactivation. Treatment with beta-propiolactone led to virus inactivation without affecting the bioactivity of IFNs as detected in the Sendai-virus-based assay.

Animals↗

The genetic toxicity of time: importance of DNA-unwinding time to the outcome of single-cell gel electrophoresis assays.

Single-cell gel electrophoresis assays (comet assays) are described in which DNA damage is assessed in mouse skin keratinocytes treated with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and beta-propiolactone (BPL) either in vitro or in vivo. The positive results observed under both conditions of test encourage the further development of the mouse skin comet assay as a screen for direct-acting in vivo genotoxins. From the outset of the present experiments we were struck by the compacted nature of the DNA in mouse skin keratinocytes. Under similar conditions of assay, rodent hepatocytes presented a uniform 'unwound' distribution of DNA over the whole nuclear region. In order to study this effect we varied what seemed to be the most obviously related assay parameter: the DNA-unwinding time. A series of experiments was conducted in which control and MNNG-treated cells were exposed to a range of alkaline DNA-unwinding times (0.3-18 h) followed by measurement of the three comet tail parameters (length, DNA content, and their product, tail moment). Each of these parameters increased with increasing time of unwinding such that the tails observed for MNNG-treated cells with 0.3 h of DNA unwinding were similar in length to the tails of control cells exposed to an 8 h DNA-unwinding time. It is concluded that DNA-unwinding time is a critical parameter of the comet assay and that it may require optimisation for each tissue/cell type studied. Further, the data alert to the prospect that agents that uniquely affect chromosomal protein superstructure may increase comet tail length/DNA content in the absence of chemically induced DNA damage. Thus, there may be two discrete classes of chemical interaction with chromosomal DNA that yield identical comet assay results, but which have different implications for the genetic toxicity of the test agent. Similar effects were observed for rat hepatocytes or mouse lymphoma cells exposed to an 18 h DNA-unwinding time, but no comet tails were produced by exposure of cells to the lysis conditions (pH 10.0) for 18 h.

Acetone↗

In vivo antibody response and in vitro CTL activation induced by selected measles vaccine candidates, prepared with purified Quil A components.

Semipurified Quil A and purified Quil A were used to prepare well-characterized subunit vaccine candidates against measles. Variation in the relative amounts of the measles virus (MV) fusion (F) protein, Quil A-components and lipids did not influence induction of antibody responses in mice, but had a pronounced effect on the capacity to induce cytotoxic T cell (CTL) activity of a CD8(+) MV F-protein specific human T cell clone in vitro. A characteristic MV iscom preparation based on the combined use of HPLC-purified Quil A-components QA-3 and QA-22 (QA-3/22) efficiently induced CTL activity in vitro. Comparable results were obtained by mixing beta-propiolactone inactivated MV with iscom-matrix QA-3/22 or free QA-22. On the basis of the data presented it was concluded that these three preparations are interesting MV vaccine candidates for further evaluation in pre-clinical experiments in a primate model.

Adjuvants, Immunologic↗

In vitro evidence of cell-mediated immunity after exposure of mice to both live and inactivated rabies virus.

Mice exposed to live or beta-propiolactone-inactivated rabies virus generated a strong, specific cell-mediated cytotoxic response which was generally maximal 6 days after inoculation. Release of 51Cr was apparently a function of immune thymus-derived lymphocytes (T cells) because it was abrogated by prior incubation of spleen cells with anti-thymus antiserum and complement but was undiminished by passage of spleen cells through nylon-wool columns. Cytotoxicity was always maximal for interactions in which thymus-derived cells and targets shared H-2 genes but, unlike the situation found in other assays of this type, considerable lysis of allogeneic, virus-infected target cells may also occur. Perhaps the most significant finding from these experiments is that an inactivated virus has been shown to stimulate a potent cytotoxic thymus-derived cell response. Manipulation of this experimental model may allow analysis of the antigens required for stimulation of cell-mediated immunity. A more practical consequence may be the development of more rational protocols for postexposure vaccination against rabies. Prior treatment of mice with antirabies antibody severely depressed the generation of cell-mediated immunity.

Animals↗

Inactivated SARS-CoV vaccine prepared from whole virus induces a high level of neutralizing antibodies in BALB/c mice.

We tested the ability of inactivated SARS-CoV vaccine to induce neutralizing antibodies in BALB/c mice. The inactivated vaccine was prepared by SARS-CoV virus propagation in Vero cells, with subsequent beta-propiolactone inactivation and Sepharose 4FF column chromatography purification. One hundred forty BALB/c female mice were divided into seven groups of 20 mice each. Of the seven groups, three groups were inoculated with 0.1, 1, and 3 microg of the vaccine without adjuvant while three other groups were inoculated at the same three dosages of vaccine with aluminum hydroxide as adjuvant, respectively. The remaining group was set up as a blank control. Each mouse was inoculated twice at an interval of 3 weeks. One week after the second immunization, mice sera were collected to detect serum neutralizing antibodies. An assay for determining neutralizing antibody titers was developed. The results can be summarized as follows: (1) higher dosages of vaccine induced higher levels of neutralizing antibody titer; (2) the level of neutralizing antibodies induced by the inoculation with aluminum hydroxide adjuvant was slightly higher than that without adjuvant, but the difference was not statistically significant.

Aluminum Hydroxide↗

Suppressive effects of interferon on syncytium formation by RD-114 virus in human transformed cells.

The RD-114 virus rapidly induced syncytia in the human transformed cell lines, RSa, RSb and IFr. Treatment of the virus with heat or ultrasonic vibration completely eliminated the syncytium-forming activity. Irradiation with u.v.-light or treatment with beta-propiolactone (BPL) reduced but did not completely destroy the activity. Pre-treatment of the cells for 16 h with 25 to 500 units/ml of human leucocyte interferon (Le-IF) or fibroblast interferon (F-IF) significantly reduced formation of syncytia by active virus or inactivated (u.v. or BPL) virus. This activity of interferon was inhibited by treatment of the cells with cycloheximide. Interferon did not increase the binding of 3H-uridine-labelled RD-114 virus to the cells. It is postulated that interferon treatment altered the plasma membrane of the cells and thus reduced their capacity to fuse.

Cell Fusion↗

The effect of non-immune IgG on antigen-antibody complexation.

Two preparations of human IgG, one acylated with beta-propiolactone (acylated IgG) and one treated at pH 4 with traces of pepsin (pH 4-IgG), were used to study the effect of non-immune IgG on antigen-antibody interactions in the antigen excess zone. Employing two immunological methods together with size-exclusion chromatography, we found that the formation of human albumin-rabbit anti-human albumin complexes was inhibited in the presence of human IgG. In addition, IgG seemed to promote the aggregation of already formed complexes. Thus, non-immune IgG may modulate immune complexation by direct molecular interactions. The effect was dependent on the size and composition of the immune complexes as well as on the conformation of the IgG molecules with respect to their shape, isotype, charge, and other surface properties. Some possible mechanisms for the reactions are discussed.

Acylation↗

Undegraded human immunoglobulin for intravenous use.

A report is presented on the development and the properties of a nondegraded human immunoglobulin preparation suitable for intravenous administration. Intravenous tolerance is achieved by elimination of anticomplementary activity through modification with beta-propiolactone. The natural antibody characteristics, such as antibody activity, molecular weight, and half-life, are retained. The findings presented open up new perspectives for an extension of the range of indication for intravenous immunoglobulin.

Adsorption↗

Inactivation of non-A, non-B virus infectivity by a beta propiolactone/ultraviolet irradiation treatment and Aerosil adsorption procedure used for preparation of a stabilized human serum.

Inoculation of chimpanzees revealed that starting material for the preparation of a pooled stabilized human serum preparation was contaminated with non-A, non-B hepatitis virus(es). This material was subjected to beta-propiolactone/ultraviolet irradiation treatment and adsorption with an insolubilized silicic acid under conditions employed for sterilization of the final product (Biseko, Biotest). The treated material did not transmit hepatitis to 2 inoculated chimpanzees. These animals were subsequently found to be susceptible to non-A, non-B infection by challenge with the untreated material. These findings demonstrate a non-A, non-B type hepatitis virus to be susceptible to inactivation by the methods employed for sterilization of this stabilized human serum preparation.

Adsorption↗

Preparation and characterization of NADP derivatives alkylated at 2'-phosphate and 6-amino groups.

Reaction of NADP with 3-propiolactone at pH 6 gave new NADP derivatives carboxyethylated at the 2'-phosphate or 6-amino group, or both: 2'-O-(2-carboxyethyl)phosphono-NAD (I), N6-(2-carboxyethyl)-NADP (II), and 2'-O-(2-carboxyethyl)phosphono-N6-(2-carboxyethyl)-NAD (III). Their structures were assigned on the basis of ultraviolet, 1H-NMR and 31P-NMR spectra, and also treatment with nucleotide pyrophosphatase or alkaline phosphatase. Carbodiimide-promoted reaction of derivative I with 1,2-diaminoethane gave 2'-O-[N-(2-aminoethyl)carbamoylethyl]phosphono-NAD (IV); derivative III gave 2'-O-[N-(2-aminoethyl)carbamoylethyl]phosphono-N6-[N-(2-aminoethyl ) carbamoylethyl]-NAD (IV). The same reaction of derivative II, on the other hand, gave a mixture of N6-[N-(2-aminoethyl)carbamoylethyl]-NADP (Va) and its 3'-phosphate isomer (Vb). The mixture was converted to Va via the 2',3'-cyclic derivative (Vc). Their structures were assigned on the basis of ultraviolet and 1H-NMR spectra, and also treatment with alkaline phosphatase or 3'-nucleotidase. All the NADP derivatives obtained in this work could be reduced with yeast glucose-6-phosphate dehydrogenase.

Alkylating Agents↗

Serological responses in pigs vaccinated with inactivated porcine parvovirus.

The safety and immunogenicity of inactivated porcine parvovirus (PPV) vaccines were investigated. Both beta-propiolactone and formalin successfully inactivated virus without destroying immunogenicity, which was considerably enhanced by incorporation of a gel adjuvant in the vaccine. Using the formalised-gel vaccine, initial antibody responses were demonstrated in susceptible piglets and adult pigs at 7 days after vaccination. These antibody responses persist at significant levels for at least 6 months after vaccination. Antibody levels increased up to 16 fold when revaccination was carried out. Vaccination of gilts with low level (passive) immunity resulted in antibody responses comparable to those recorded in susceptible pigs. The vaccine was safe as determined by absence of residual virus in the vaccine, absence of viraemia and excretion in vaccinted stock, and absence of effect on litters of sows vaccinated at different gestational ages. Vaccine stored at 4 degrees C for 6 months was as immunogenic as fresh vaccine.

Animals↗

Effect of two disinfectant treatments on laboratory analyses.

Inactivation of human immunodeficiency virus (HIV), the retrovirus associated with the acquired immune deficiency syndrome (AIDS), can be achieved both by heating at 56 degrees C and by chemical disinfection with beta-propiolactone (BPL). Such treatment of specimens from patients with suspected AIDS or antibodies to HIV could reduce any occupational risk to laboratory staff. This study demonstrates the effects of these treatments on laboratory analyses. Heat treatment of plasma caused clinically insignificant alteration in the results of electrolyte, urea, creatinine, albumin and glucose concentration, but significant alteration to total protein estimation and the activities of many enzymes. Haemolysis and cell agglutination occurred in many specimens of whole blood, making them unsuitable for haematological analyses. BPL caused less reduction of enzyme activities, and assay of many analytes, including electrolytes, plasma proteins, haemoglobin, white cell and platelet counts, was not significantly affected.

Acquired Immunodeficiency Syndrome↗

Glycidol degrades scrapie mouse prion protein.

Agents of transmissible spongiform encephalopathy (prion) are known to be extremely resistant to physicochemical inactivation procedures such as heat, radiation, chemical disinfectants such as detergents, alcohols, glutaraldehyde, formalin, and so on. Because of its remarkable resistance, it is difficult to inactivate prion. Chemical inactivation seems to be a practical method because it is applicable to large or fixed surfaces and complicated equipment. Here, three epoxides: beta-propiolactone, propylene oxide, and glycidol (GLD) were examined of their inactivation ability against scrapie-mouse prion protein (PrP(Sc)) under various conditions of chemical concentration, incubation time, and temperature. Among these chemicals, GLD worked most effectively and degraded PrP into small fragments. As a result of the bioassay, treatment with 3% GLD for 5 hr and 5% GLD for 2, 5 hr or 12 hr at room temperature prolonged the mean incubation time by 44, 30, 110 and 73 days, respectively. From dose-incubation time standard curve, the decrease in infectivity titers were estimated as 10(3) or more. Therefore, degradation of PrP(Sc) by GLD decreased the scrapie infectivity. It is also suggested that pH and salt concentrations influence the effect of GLD. Although further study is necessary to determine the optimal condition, GLD may be a potential prion disinfectant.

Animals↗

Development of collagenous fibres in autologous and preserved homologous tendon grafts.

Collagen synthesis has been studied in preserved autologous and homologous tendon grafts, applied in dogs. The stages of collagen morphogenesis observed in the synthetizing fibroblasts appearing in the decomposing original structure of the transplants as well as in the extracellular ground substance are described. The results suggest that autologous tendon grafts and homologous ones preserved by irradiation, stored in cold physiological saline and beta-propiolactone, are rebuilt within eight weeks; meanwhile the original collagenous fibre structure is decomposed. When other preserving procedures such as deep-freezing or gamma irradiation are applied recomposition of the graft is retarded or fails to occur; the result is a cicatrizing adhesion.

Animals↗

[Bacteriophages from micrococci (author's transl)].

Using 14 indicator strains we investigated the possibilities of isolation of bacteriophages from micrococci (two strains of M. luteus, three strains of M. varians and one strain of M. roseus). Three phages were released after mitomycin C-induction, four phages after UV-rays-induction. These seven strains seem to be the first known bacteriophages, which were released from naturally lysogenic micrococci. Induction experiments with beta-propiolacton and dimethylsulfate as well as tests of spontaneous lysogeny produced only negative results.

Bacteriophages↗