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At least 523 records · Page 29Linked to original sources
PubMed1974

Analysis of a viral agent isolated from multiple sclerosis brain tissue: characterization as a parainfluenzavirus type 1.

A virus originally isolated from cell cultures obtained by lysolecithin-induced fusion of human multiple sclerosis brain cells with CV-1 cells has been analyzed for its antigenic, RNA, and polypeptide compositions, and for selective biological properties. Our findings establish that this isolate, designated 6/94 virus, contains a 50S RNA genome and is, as yet, indistinguishable from Sendai virus in its antigenic and total polypeptide compositions. Despite these similarities, the 6/94 and Sendai viruses differ in certain phenotypic properties. 6/94 virus is markedly less cytocidal for chick fibroblasts, especially at 37 C and, after beta-propiolactone inactivation, it possesses a greater capacity for cell fusion and a lower toxicity than does comparably treated Sendai virus. In addition, 6/94 virus shows greater hemolytic activity.

Animals↗
PubMed1993

Formalin inactivation of vesicular stomatitis virus impairs T-cell- but not T-help-independent B-cell responses.

The effects of formalin on the infectivity and immunogenicity of vesicular stomatitis virus (VSV) serotype Indiana were investigated. We found that formalin inactivation of VSV prevents infection of Vero cells in a concentration- and time-dependent manner, as shown by fluorometric cell analysis and inhibition of plaque formation. Inactivated VSV failed to induce significant cytotoxic T-lymphocyte responses in vivo or after restimulation in vitro. In contrast, the early immunoglobulin M (IgM) response, which is T help independent in the VSV system, was unaltered, suggesting normal antigenicity for and induction of B cells. However, no switch to IgG occurred, demonstrating failure of induction of T help. If cross-reactive T help was provided by previous infection with a second serotype of VSV (New Jersey), the IgG response was almost completely restored, confirming that the absence of IgG was due to lack of T help. A formalin-treated preparation of glycoprotein of VSV led to a delayed but otherwise normal IgG response, whereas treatment of VSV with UV light or beta-propiolactone reduced IgG titers to the same extent as did formalin. These results suggest that loss of infectivity and the ensuing lack of amplification of viral antigens of formaldehyde-inactivated VSV is the major factor impairing induction of specific T-helper cell responses.

Animals↗
PubMed1976

Degenerative changes in aortic root allografts placed in the right ventricular outflow tract of growing puppies.

Differently prepared aortic root allografts were implanted in the right ventricular outflow tract of growing puppies to determine the site of origin and progress of degenerative changes in these conduits. The three preparations assessed were as follows: group A, fresh and sterile grafts; group B, antibiotic sterilized grafts in nutrient medium; and group C, beta-propiolactone sterilized grafts. Although calcification of the aortic wall occurred in all groups, the aortic leaflets were minimally affected. A correlation between viability and lack of calcification and between viability and long-term function is emphasized.

Animals↗
PubMed1984

Investigation of the blood-brain barrier for IgG in inflammatory syndromes of the central nervous system.

To investigate whether an intravenously administered compound of the IgG class is able to penetrate the CSF barrier despite its high molecular weight, 12 hepatitis B surface antibody (anti-HBs)-negative patients received 20 ml each of a beta-propiolactone-treated IgG compound with a high anti-HBs titer (1:115,000) as a marker. 8 had an inflammatory CSF syndrome. In cases of inflammatory CSF syndromes, significantly more marked IgG crossed the blood-brain barrier, this could be of considerable clinical importance.

Adult↗
PubMed2003

Platelet adhesion onto segmented polyurethane surfaces modified by carboxybetaine.

Polyurethanes are widely used as blood-contacting biomaterials due to their good biocompatibility and mechanical properties. Nevertheless, their blood compatibility is still not adequate for more demanding applications. Surface modification is an effective way to improve the hemocompatibility for biomaterials. The purpose of present study was to synthesize a novel nonthrombogenic biomaterial by modifying the surface of polyurethane with Zwitterions of carboxybetaine monomer. The films of polyurethane were grafted with two kinds of carboxybetaine by a three-step procedure. In the first step, the film surfaces were treated with hexamethylene diisocyanate (HDI) in toluene at 50 degrees C in the presence of di-n-butyl tin dilaurate (DBTDL) as a catalyst. The extent of the reaction was measured by ATR-FT-IR spectra: a maximum number of free NCO group was obtained after a reaction time of 90 min. In the second step, the hydroxyl group of N,N-dimethylethylethanolamine (DMEA) or 4-dimethylamino-1-butanol (DMBA) was allowed to react in toluene with isocyanate groups bound on surface. In the third step, carboxybetaines were formed in the surface through the ring-opening reaction between tertiary amine of DMEA or DMBA and beta-propiolactone (PL). It was characterized by ATR-FT-IR and XPS that the grafted surfaces were composed of carboxybetaine. The results of the contact angle measurements showed that they were strongly hydrophilic. Platelet adhesion tests showed that films grafted carboxybetaine have good blood compatibility, as featured by the low platelet adhesion.

Betaine↗
PubMed1983

Approach to risk assessment for genotoxic carcinogens based on data from the mouse skin initiation-promotion model.

Tumor induction data in the mouse skin initiation-promotion system were found to be consistent with a quadratic function where the coefficient of the linear term depended on the dose of the promoter. The model implies that the existence of promoters may be more important at low doses of the carcinogen than at high doses where most testing is performed. Experiments are described showing that the initiating effect of carcinogenic chemicals, such as benzo(a)pyrene, 7,12-dimethyl-benz(a)anthracene, nitroquinoline oxide and beta-propiolactone, accumulates in a linear, irreversible manner at low doses. Even when 7,12-dimethylbenz(a)anthracene was applied intragastrically to pregnant females, initiating activity was found in the skins of exposed offspring about in proportion to dose applied and number of cells at risk. The initiated cells essentially represent a potential for cancer that has a high probability for expression in the presence of a promoter. Risk then can be interpreted in terms of the accumulated dose of initiator which alone presents a small risk of cancer. However, a promoter may substantially expand the overall risk, possibly by clonally expanding the initiated cells. Promotion needs to be sustained since there is a reduction of cancer risk if promotion is ended early. Some tissues, such as mouse bladder, may be intrinsically promoted more than others so that comparisons between tissues and between species are best made when the combination of intrinsic promotion and response to extrinsic promotion are comparable.

Animals↗
PubMed1986

Phorbol myristate acetate and catechol as skin cocarcinogens in SENCAR mice.

The enhancement of the carcinogenicity of benzo(a)pyrene (B[a]P) and beta-propiolactone (BPL) by the mouse skin cocarcinogens phorbol myristate acetate (PMA) and catechol were examined in female SENCAR mice, 30 per group. The carcinogen and cocarcinogen were applied simultaneously, three times weekly for 490-560 days. B(a)P and BPL were used at constant doses of 5 and 50 micrograms, respectively, in all experiments. PMA was used at three doses, 2.5, 1.0, and 0.5 micrograms per application, and catechol was used at one dose, 2 mg per application. Control groups included animals that received carcinogen only, cocarcinogen only, acetone only, and no treatment. The carcinogenicity of B(a)P and BPL were enhanced by the cocarcinogens, particularly in terms of tumor multiplicity. For both carcinogens, the most marked cocarcinogenic effects were observed at the lowest dose of PMA used (0.5 microgram per application). This observation applied for days to first tumor, animals with tumors, tumor multiplicity, and incidence of malignant skin tumors. Catechol applied alone did not induce any tumors; with PMA alone there were significant incidences of benign and malignant tumors, e.g., at a dose of only 0.5 microgram per application, 15 of 30 animals had 28 tumors, 5 of which were squamous carcinomas. In two-stage carcinogenesis experiments with 7,12-dimethylbenz(a)anthracene (DMBA) as initiator and PMA as promoter, SENCAR mice showed a greater susceptibility to tumor induction when compared to ICR/Ha mice used in earlier work. This susceptibility was most notable in terms of rate of tumor appearance and tumor multiplicity.

Animals↗
PubMed1991

Physicochemical properties of pseudorabies virus hemagglutinin.

Pseudorabies virus hemagglutinin was readily adsorbed on mouse erythrocytes at 4, 22, or 37 degrees C, but not on cattle erythrocytes. The adsorbed hemagglutinin could not be eluted from the cells by resuspending in phosphate-buffered saline (PBS), by incubating at 37 or 50 degrees C, or by incubating in the presence of neuraminidase. The receptor on mouse erythrocytes for the hemagglutinin was inactivated by trypsin, but not by neuraminidase, sodium deoxycholate (DOC), potassium periodate (KIO4), dithiothreitol (DTT), 2-mercaptoethanol (2-ME) and formalin. The hemagglutinin was inactivated by trypsin, alpha-amylase, pepsin, DOC, KIO4, and ethylendiamine-tetraacetic acid (EDTA), but not by papain, beta-glucosidase, phospholipase C, neuraminidase, DTT, 2-ME, Tween-80, ethylether, chloroform, trichloro-trifluoroethane, beta-propiolactone and formalin, suggesting that the hemagglutinin active component involved glycoproteins. The hemagglutinin was stable at 37 degrees C for lower temperatures but not at 60 degrees C or higher. The hemagglutinin activity was resistant to ultraviolet irradiation, while the infectivity was very susceptible. The hemagglutinin and the infectivity were readily sedimented by ultracentrifugation at 48,000 x g for 3 hr. In rate zonal centrifugation of the preparation on a sucrose density gradient, the hemagglutination (HA) activity showed a sharp peak at 1.22 g/ml coinciding with the peak of infectivity. The HA activity in the peak fraction seemed to be structually associated with virus particles. After fractionation of the virus by Nonidet P-40, the HA activity was found only in the fraction of the envelope material, indicating that the hemagglutinin is situated in the viral envelop.

Adsorption↗
PubMedDate not supplied

Long-term follow-up of HIV-1-infected Thai patients immunized with Remune monotherapy.

PURPOSE: The purpose of this 2-year follow-up study was to investigate the long-term effect of Remune as monotherapy for HIV-1 infection. BACKGROUND: Participants previously enrolled in the phase II double-blind, randomized, adjuvant-controlled study of the HIV-1 Immunogen (Remune) were followed for 2 years. Open-label immunization with Remune monotherapy was given to each participant every 12 weeks. Remune, a gp 120-depleted HIV-1 that was inactivated in beta-propiolactone and irradiation, was emulsified with mineral oil (incomplete Freund's adjuvant). METHOD: In Study 2101B, the effect of four doses of Remune given every 12 weeks over 40 weeks was compared to placebo in 297 asymptomatic type E HIV-infected patients [Churdboonchart et al., 2000]. A group of 17 volunteers were separated into a subset study and another 57 were excluded from analysis due to discontinuation or addition of other treatments. This 2-year follow-up study continued with open-label dosing of HIV-1 Immunogen every 12 weeks for the remaining 223 patients. Changes in CD4+ cells, CD8+ cells, and body weight were monitored at each patient visit. RESULTS: Overall, immunizations were safe; common adverse events were tolerable injection site reactions. CD4+ T-cell counts remained stable over the 132-week observation period for this cohort with a slight increase of 36.01 cells/microL. CD8+ T-cell counts showed an increase from baseline during the follow-up period (415.21 cells/microL). Furthermore, we also observed an increase in body weight from baseline (1.08 kg) at week 132. In addition, baseline CD4 count appeared to predict CD4 count at week 132 (slope = 0.31, p <.0001). CONCLUSION: These results suggest that long-term treatment of HIV-1 infection with Remune monotherapy is safe and results in a stabilization of CD4+ counts. Furthermore, it is likely that HIV-1 therapeutic immunization may show its greatest clinical benefit in participants with higher CD4+ cell counts. Such an approach may have important ramifications in developing countries where access to antiviral drugs is limited and also in early chronic HIV-1 infection when CD4+ cells are still over 300 cells/microL in order to limit the cost and toxicity.

AIDS Vaccines↗
PubMed1992

Consideration of inactivated rabies vaccines as oral immunogens of wild carnivores.

An experimental beta-propiolactone (BPL)-inactivated rabies virus vaccine was evaluated for the oral immunization of captive raccoons (Procyon lotor) and red foxes (Vulpes vulpes). None of 10 red foxes administered a single 1.0 ml dose of BPL-inactivated rabies virus vaccine (PM strain; 100 or 500 micrograms protein) per os developed detectable anti-rabies virus-neutralizing antibodies (VNA) at any time over 8 wk of observation. Foxes were excluded from further study. In two different groups of five to six raccoons, each administered a single 1.0 ml dose of BPL-inactivated rabies virus vaccine (ERA strain) per os, at concentrations of 100 or 400 micrograms protein, only a single animal in each group demonstrated evidence of seroconversion within 4 wk. In contrast, instillation of a single dose (500 micrograms protein) of BPL-inactivated rabies virus vaccine (ERA strain), directly into the small intestine via fiberoptic endoscope, or ERA vaccine (800 micrograms protein) instillation to the buccal cavity by needle-less syringe, resulted in the production of rabies-specific VNA and protection against lethal rabies infection in three of six, and in four of six raccoons, respectively; all seven control raccoons succumbed to street virus challenge. These preliminary challenge studies, while somewhat encouraging, demonstrate that considerable quantities of purified viral antigen are required for even minimal oral efficacy against lethal rabies infection. At the present time, therefore, potent, self-replicating, attenuated, or recombinant viruses offer the most versatile, economic, efficacious, and safe solutions to terrestrial rabies control of free-ranging carnivores.

Administration, Oral↗
PubMed1976

[Effectiveness and tolerance of the rabies vaccine Lyssavac Berna].

Rabies vaccine derived from human diploid cells (Wyeth, Merieux) and the duck embryo vaccine Lyssavac Berna are prepared from beta-propiolactone-inactivated Pitman-Moore vaccine virus strain. A group of 113 seronegative veterinary students was vaccinated with Lyssavac Berna according to the 4-dose immunization schedule recommended by WHO. Seroconversion was obtained in all test persons. The vaccine was very well tolerated. In agreement with the literature we also found a relatively fast decline in the neutralizing antibody titer after this immunization procedure. However, a booster injection after one year resulted in an antibody rise with titer values comparable with or higher than those obtained after the primary vaccination course. An annual single revaccination dose should be sufficient to protect people at risk.

Adult↗
PubMed1976

Freeze-drying of a purified human diploid cell rabies vaccine.

A rabies vaccine prepared in human diploid cell strains was purified by continuous-flow sucrose density gradient centrifugation. The peak fractions containing 35-40% sucrose were diluted with a stabilizer consisting of degraded gelatine in a Tris-EDTA-buffer, and then inactivated with beta-propiolactone and freeze-dried to a residual moisture of approximately 2.5%. This vaccine was stable as proved by accelerated stability tests.

Cell Line↗
PubMed2000

[Macaque immunization with virions purified from a primary isolate of the human immunodeficiency virus type 1 induced enhancement antibodies].

Six Rhesus macaques were hyperimmunized with either live infectious human immunodeficiency virus type 1 (HIV-1) or with beta-propiolactone--or formalin--inactivated HIV-1. The virus used was HIV-1 BX08, a primary virus isolate grown in human PBMC. Instead of eliciting virus-neutralizing antibodies, this regimen induced antibodies that enhanced HIV-1 infectivity for PBMC by 10 to 90 fold. Enhancement was also seen in a cell-to-cell fusion assay using a Semliki Forest virus replicon to express BX08 gp160 in CD4+, CCR5+ HeLa cell cultures. These observations raise the concern that whole virus particles-based HIV-1 vaccines might elicit enhancing antibodies that could play a facilitating role in the transmission and/or evolution of the disease.

Animals↗
PubMedDate not supplied

[Development of of non-immunising, paraspecific vaccine from attenuated pox viruses: a new type of vaccine].

The various research periods leading to the development of paraspecific vaccines are described. Paraspecific vaccines are new, pyrogen-free, non-toxic preparations that contain non-immunising antigens and can be used to generate endogenic protective, non-antigen specific mechanisms in the sense of paramunization in humans and animals. They consist of highly attenuated and inactivated (0.05% beta-propiolactone) virus strains of various poxvirus genera. They activate the T helper cells and cellular elements of the paraspecific (innate) immune system and initiate the associated production and release of cytokines (cytokine cascade) with the goal of eliminating dysfunctions of the immune systems, rapidly enhancing the individual's non-pathogen- and non-antigen-specific defences and exerting a regulatory effect on the interplay between the immune, hormone, nervous and vascular systems (signal-transduction mediators). They can be used systemically (intramuscularly) and locally (mucous membranes, skin). Immunization with paraspecific vaccines does not lead to postvaccinal complications and can be carried out as often as necessary, even for a number of years. They are compatible with conventional medicines and conventional specific vaccines. Closely linked protein complexes in the envelopes of the virus particles are responsible for their efficacy some of those envelope protein complexes possess the properties of weak super antigens. Paraspecific vaccines have proved effective in combating viral infections, in particular herpes and hepatitis B and C infections, and chronic inflammatory diseases, and also as adjuvant therapy for tumours, for curing stress-related disturbances and dysfunctions of the immune system.

Animals↗
PubMed1975

[Chemical induction of lysogeny of Staphylococcus aureus (author's transl)].

Concerning the chemical induction of lysogeny of Staphylococcus aureus only little is known. Therefore, we performed induction experiments on 43 Staph, aureus strains using nine mutagenic substances and 15 chemotherapeutics. Only three of the nine mutagenic substances (beta-propiolacton, nitrosoguanidin and mitomycin C) and six of the 15 chemotherapeutics (penicillin G, ampicillin, cephalothin, nebacetin, novobiocin and nalidixie acid) showed inducing effects. Our results demonstrated furtheron that the lysogeny inducing ability is dependent on strains and substances used.

Anti-Bacterial Agents↗
PubMed1975

The role of interferon in interference and auto-interference elicited by Newcastle disease virus.

Newcastle disease virus (NDV) strains interfere in different degree with the growth of the velogenic NDV strain Texas GB (homologous interference) and Sindbis virus (heterologous interference) in chick embryo fibroblast cells. Homologous interference was elicited by interferon-producing live or UV-inactivated strains and non-interferon-producing live or beta-propiolactone-inactivated strains and it was not influenced by actinomycin D. Thus, interferon had apparently no role in homologous interference of NDV. The growth of Sindbis virus was, however, much more inhibited by interferon-producing live or UV-inactivated NDV strains than with non-inducing ones and the interference was reversible by actinomycin D. Thus heterologous interference is apparently mediated by interferon. In chicken cells infected with the mesogenic NDV strain H, virus yields were 50 to 100 times lower at multiplicities of infection above 0.1 p.f.u./cell than below it. The interferon formed during infection played no role in auto-interference, but may well be held responsible for the mild cytopathic effect observed.

Animals↗
PubMedDate not supplied

Preparation of Newcastle disease virus hemagglutination-inhibition test antigen.

A method of preparing antigen for Newcastle hemagglutination-inhibition (HI) tests is described; polyethylene glycol precipitation is used for the virus concentration. The virus was inactivated with either formalin or beta-propiolactone. Glycerin was used to stabilize the hemagglutinin activity of the antigen. The stability, uninfectivity, and slow eluting features of the antigen should aid in obtaining accurate HI results without the risks inherent in the use of live virus.

Animals↗
PubMedDate not supplied

Newcastle disease virus pathogenesis in the respiratory tract of local or systemic immunized chickens.

Establishment of selective immunity, local or systemic, made it possible to evaluate the pathogenesis of Newcastle disease virus (NDV) in the respiratory tract of chickens that were previously immunized with beta-propiolactone-inactivated antigen. NDV was inoculated intranasally or intramuscularly to chickens in different states of immunity (local or systemic). Humoral antibodies protected chickens against intranasal as well as intramuscular infection. Local antibodies, on the other hand, conferred immunity only against intranasal challenge. The respiratory tract supported multiplication of the virus, producing a self-limited subclinical infection. Replication of the virus in this system was negligible, playing only a minor role in the pathogenesis of the disease.

Administration, Intranasal↗