Evaluation of Stability, Inactivation, and Disinfection Effectiveness of Mpox Virus

BACKGROUND

Mpox virus (MPXV) infections have increased in many countries since May 2022, increasing demand for diagnostic tests and research on the virus. To ensure personnel safety, appropriate and reliable measures are needed to disinfect and inactivate infectious samples; Methods: We evaluated the stability of infectious MPXV cultures stored at different temperatures and through freeze-thaw cycles. Heat physical treatment (56 °C, 70 °C, 95 °C), chemical treatment (beta-propiolactone (BPL)) and two commercialized disinfectants (Micro-Chem Plus (MCP) and ethanol) were tested against infectious MPXV cultures; Results: The results indicated that MPXV stability increases with lower temperatures. The MPXV titer was stable within three freeze-thaw cycles and only decreased by 1.04 log10 (lg) 50% cell culture infective dose (CCID50) per milliliter (12.44%) after twelve cycles. MPXV could be effectively inactivated at 56 °C for 40 min, 70 °C for 10 min, and 95 °C for 5 min. For BPL inactivation, a 1:1000 volume ratio (BPL:virus) could also effectively inactivate MPXV. A total of 2% or 5% MCP and 75% ethanol treated with MPXV for at least 1 min could reduce >4.25 lg; Conclusions: MPXV shows high stability to temperature and freeze-thaw. Heat and BPL treatments are effective for the inactivation of MPXV, while MCP and ethanol are effective for disinfection, which could help laboratory staff operate the MPXV under safer conditions and improve operational protocols.

Perspectives for the creation of a new type of vaccine preparations based on pseudovirus particles using polio vaccine as an example

Traditional antiviral vaccines are currently created by inactivating the virus chemically, most often using formaldehyde or β-propiolactone. These approaches are not optimal since they negatively affect the safety of the antigenic determinants of the inactivated particles and require additional purification stages. The most promising platforms for creating vaccines are based on pseudoviruses, i.e., viruses that have completely preserved the outer shell (capsid), while losing the ability to reproduce owing to the destruction of the genome. The irradiation of viruses with electron beam is the optimal way to create pseudoviral particles. In this review, with the example of the poliovirus, the main algorithms that can be applied to characterize pseudoviral particles functionally and structurally in the process of creating a vaccine preparation are presented. These algorithms are, namely, the analysis of the degree of genome destruction and coimmunogenicity. The structure of the poliovirus and methods of its inactivation are considered. Methods for assessing residual infectivity and immunogenicity are proposed for the functional characterization of pseudoviruses. Genome integrity analysis approaches, atomic force and electron microscopy, surface plasmon resonance, and bioelectrochemical methods are crucial to structural characterization of the pseudovirus particles.

Effect of an Inactivated Vaccine Against SARS-CoV-2 on Safety and Immunogenicity Outcomes: Interim Analysis of 2 Randomized Clinical Trials

IMPORTANCE

A vaccine against coronavirus disease 2019 (COVID-19) is urgently needed.

OBJECTIVE

To evaluate the safety and immunogenicity of an investigational inactivated whole-virus COVID-19 vaccine in China.

INTERVENTIONS

In the phase 1 trial, 96 participants were assigned to 1 of the 3 dose groups (2.5, 5, and 10 μg/dose) and an aluminum hydroxide (alum) adjuvant-only group (n = 24 in each group), and received 3 intramuscular injections at days 0, 28, and 56. In the phase 2 trial, 224 adults were randomized to 5 μg/dose in 2 schedule groups (injections on days 0 and 14 [n = 84] vs alum only [n = 28], and days 0 and 21 [n = 84] vs alum only [n = 28]).

DESIGN, SETTING, AND PARTICIPANTS

Interim analysis of ongoing randomized, double-blind, placebo-controlled, phase 1 and 2 clinical trials to assess an inactivated COVID-19 vaccine. The trials were conducted in Henan Province, China, among 96 (phase 1) and 224 (phase 2) healthy adults aged between 18 and 59 years. Study enrollment began on April 12, 2020. The interim analysis was conducted on June 16, 2020, and updated on July 27, 2020.

MAIN OUTCOMES AND MEASURES

The primary safety outcome was the combined adverse reactions 7 days after each injection, and the primary immunogenicity outcome was neutralizing antibody response 14 days after the whole-course vaccination, which was measured by a 50% plaque reduction neutralization test against live severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

RESULTS

Among 320 patients who were randomized (mean age, 42.8 years; 200 women [62.5%]), all completed the trial up to 28 days after the whole-course vaccination. The 7-day adverse reactions occurred in 3 (12.5%), 5 (20.8%), 4 (16.7%), and 6 (25.0%) patients in the alum only, low-dose, medium-dose, and high-dose groups, respectively, in the phase 1 trial; and in 5 (6.0%) and 4 (14.3%) patients who received injections on days 0 and 14 for vaccine and alum only, and 16 (19.0%) and 5 (17.9%) patients who received injections on days 0 and 21 for vaccine and alum only, respectively, in the phase 2 trial. The most common adverse reaction was injection site pain, followed by fever, which were mild and self-limiting; no serious adverse reactions were noted. The geometric mean titers of neutralizing antibodies in the low-, medium-, and high-dose groups at day 14 after 3 injections were 316 (95% CI, 218-457), 206 (95% CI, 123-343), and 297 (95% CI, 208-424), respectively, in the phase 1 trial, and were 121 (95% CI, 95-154) and 247 (95% CI, 176-345) at day 14 after 2 injections in participants receiving vaccine on days 0 and 14 and on days 0 and 21, respectively, in the phase 2 trial. There were no detectable antibody responses in all alum-only groups.

CONCLUSIONS AND RELEVANCE

In this interim report of the phase 1 and phase 2 trials of an inactivated COVID-19 vaccine, patients had a low rate of adverse reactions and demonstrated immunogenicity; the study is ongoing. Efficacy and longer-term adverse event assessment will require phase 3 trials.

TRIAL REGISTRATION

Chinese Clinical Trial Registry Identifier: ChiCTR2000031809.

β-glucan and anisodamine can enhance the immersion immune efficacy of inactivated cyprinid herpesvirus 2 vaccine in Carassius auratus gibelio

As one of the most important fish in freshwater aquaculture, gibel carp (Carassius auratus gibelio) is easily susceptible to Cyprinid herpesvirus 2 (CyHV-2). Immersion vaccination has attracted many researchers due to its simple operation in preventing infectious diseases. However, the unavoidable disadvantage is that the immersion vaccine must be used with adjuvants to get a better performance. In this study, gibel carps were vaccinated by a 60 min bath in a β-propiolactone-inactivated Cyprinid herpesvirus 2, mixed with DTT, β-glucan, anisodamine and scopolamine, respectively. After immunization, the fishs were challenged by CyHV-2 in 2 weeks. By analyzing pathological section, we found that β-glucan, anisodamine and scopolamine groups protected the gibel carp compared to the control group, which was consistent with the trend of survival rate. Specifically, β-glucan group in serum appeared best on lysozyme, TSOD and complement C3. Real time quantitative RT-PCR results demonstrated that in both spleen and head kidney tissues, mRNA expressions of typical Th1 immune response cytokines IL-2 and IFN-γ2 in β-glucan group and anisodamine group were significantly higher than other groups and the level of immunoglobulins related to systemic immunity (IgM) and mucosal immunity (IgZ) were also enhanced in the immune period. DTT group slightly affected immune gene and serum enzyme activity, while did not show an adjuvant effect on survival rate. In addition, four adjuvant groups could obviously inhibit CyHV-2 replication. This study explored and proved the good efficiency of β-glucan or anisodamine as immersion immune adjuvant and also provided reference for improving the efficiency of immersion immunity.

Protective Effects of [6]-Gingerol Against Chemical Carcinogens: Mechanistic Insights

[6]-Gingerol from ginger has received considerable attention as a potential cancer therapeutic agent because of its chemopreventive and chemotherapeutic effects, as well as its safety. In the current study, we examined [6]-gingerol as a natural scavenger of nine ultimate chemical carcinogens to which we are frequently exposed: glycidamide, styrene oxide, aflatoxin B1 exo-8,9-epoxide, β-propiolactone, ethylene oxide, propylene oxide, 2-cyanoethylene oxide, chloroethylene oxide, and vinyl carbamate epoxide. To evaluate [6]-gingerol efficacy, we expanded our research with the examination of glutathione-the strongest natural scavenger in human cells. The corresponding activation free energies were calculated using Hartree-Fock method with three flexible basis sets and two implicit solvation models. According to our results, [6]-gingerol proves to be an extremely effective scavenger of chemical carcinogens of the epoxy type. On the other hand, with the exception of aflatoxin B1 exo-8,9-epoxide, glutathione represents a relatively poor scavenger, whose efficacy could be augmented by [6]-gingerol. Moreover, our quantum mechanical study of the alkylation reactions of chemical carcinogens with [6]-gingerol and glutathione provide valuable insights in the reaction mechanisms and the geometries of the corresponding transition states. Therefore, we strongly believe that our research forms a solid basis for further computational, experimental and clinical studies of anticarcinogenic properties of [6]-gingerol as well as for the development of novel chemoprophylactic dietary supplements. Finally, the obtained results also point to the applicability of quantum chemical methods to studies of alkylation reactions related to chemical carcinogenesis.

Immune response and protection in gibel carp, Carassius gibelio, after vaccination with β-propiolactone inactivated cyprinid herpesvirus 2

Herpesviral haematopoietic necrosis (HVHN) of gibel carp (Carassius gibelio) is a newly emerged infectious disease caused by cyprinid herpesvirus 2 (CyHV-2) and has caused huge economic losses in aquaculture operations. Currently, no effective methods are available for the control of the disease. In this study, β-propiolactone inactivated cyprinid herpesvirus 2 (CyHV-2) vaccine was prepared, and the immune response and protection in cultured gibel carp after vaccination was thoroughly investigated. This included blood cell counting and classification, phagocytic activity, lysozyme and superoxide dismutase activity, neutralizing antibody titration, immune gene expression analysis, and determination of the relative percent survival in vaccinated gibel carp. The results of blood cell counts indicated that the numbers of the red and white blood cells in the peripheral blood of immunized gibel carp increased significantly at day 4 and day 7 after vaccination (p < 0.01). The differential leukocyte count of neutrophils and monocytes were significantly different compared to the control group at day 4 and 7 and the percentage of lymphocytes reached a peak at day 21. The phagocytic percentage and phagocytic index peaked at day 4 post-vaccination. The lysozyme activity and superoxide dismutase activity were significantly increased compared to the control group (p < 0.01). The serum neutralizing antibody titer peaked (203.03 ± 13.44) at day 21. The qPCR analysis revealed that the expression of the immune genes interlukin 11 and complement component C3 were significantly up-regulated in the immunized group. The challenge test demonstrated that the immunized group had a relative survival rate of 71.4%. These results indicate that the inactivated CyHV-2 vaccine induced both non-specific and specific anti-viral immune responses that resulted in significant protection against HVHN disease and mortality in gibel carp.

Anticomplementary activity of equine whole IgG antivenoms: comparison of three fractionation protocols

Early adverse reactions occur in a number of patients treated with heterologous antivenoms and have been associated with anticomplementary activity (ACA). In order to reduce the ACA of equine whole IgG antivenoms produced by caprylic acid fractionation, three different fractionation protocols were compared: (a) routine caprylic acid fractionation; (b) caprylic acid fractionation followed by beta-propiolactone treatment; and (c) caprylic acid fractionation followed by ion-exchange chromatography using a quaternary ammonium membrane. The three protocols yielded products with similar physicochemical characteristics and anti-Bothrops asper venom antibody titers, except that ion-exchange purified antivenom had a lower protein concentration. Antivenoms fractionated by using beta-propiolactone or filtration through quaternary ammonium membrane had a significantly reduced in vitro ACA. A preparation of caprylic acid-fractionated antivenom was heated in order to induce the formation of protein aggregates; however, its ACA was similar to non-heated antivenom. None of the antivenoms affected the hemolytic activity of serum complement in rabbits after a bolus intravenous administration. It is concluded that (a) beta-propiolactone and quaternary ammonium membranes significantly reduce in vitro ACA of caprylic acid-fractionated equine antivenom, and (b) the validity of in vitro ACA as a predictor of EAR needs to be reexamined in clinical and experimental studies, since it may not adequately predict in vivo complement activation by antivenoms.

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.

Comparative effects of beta-propiolactone on mice, mouse-derived cell cultures, and Venezuelan equine encephalomyelitis virus

Studies were made comparing the toxicity of beta-propiolactone (BPL) for mammalian (mouse) cells in vitro and for mice and for Venezuelan equine encephalomyelitis (VEE) virus which is highly cytopathogenic for each. The mammalian cells grown in tissue culture were found to be adversely affected by BPL in concentrations ranging from 0.001 to 0.1 mg/ml of supernatant fluid. The difference in response was influenced by the menstruum in which the BPL was suspended and the difference in cell types tested. Tenfold less BPL appeared to be required to destroy the cells when it was suspended in a balanced salt solution than when it was suspended in protein-containing solutions such as beef heart infusion broth or medium 199 plus 20% horse serum. Secondary embryonic mouse lung cells seemed slightly more adversely affected by BPL than the established embryonic lung or L cells. BPL given to mice by intranasal instillation and by intracerebral injection was lethal to half of the animals within 2 days at doses of 0.31 and 0.39 mg, respectively. Higher concentrations of BPL were required to rapidly inactivate the virus in vitro than were required to kill mice or to cause a toxic effect on cells in culture. It required 10 mg/ml of BPL to completely inactivate a high-titered VEE virus preparation in 5 min and 1 mg/ml to inactivate most, but not all, of the virus in 15 min. A concentration of 0.1 mg/ml of BPL had only a slight effect on the virus after a period as long as 60 min. Evidence is presented indicating that simultaneous inactivation of all of the properties of the VEE virus particles by BPL aerosols did not occur at the same time but that, after treatment, the virus possessed a limited ability to immunize mice despite a loss in infectivity.

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.

Inactivation of viruses found with plasma proteins

Plasma protein solutions such as albumin and intramuscular immune globulin have long histories of viral safety. Coagulation factor concentrates as traditionally manufactured frequently transmitted HBV, HCV, and HIV. Indeed, it is probable that every vial of concentrate contained infectious HCV. Modern coagulation factor concentrates have a greatly improved safety record arising, principally, from the implementation of virucidal procedures. It is interesting to note that the same methods that failed to substantially reduce NANBHV transmission in clinical studies are those that were found to inactivate less than 10(4) ID50 of HIV, HBV, and/or HCV in preclinical studies (Table 17-5). Implementation even of these methods nearly eliminated the transmission of HIV by coagulation factor concentrates. A summary of the results of the most successful procedures is given in Table 17-10. The results show 0/564 patients had evidence of HIV transmission, 6/151 patients had evidence of HBV transmission, and 2/301 patients had evidence of HCV transmission. As compared with those procedures described in Table 17-5, the greater kill of HIV, HBV, and NANBHV demonstrated preclinically, and the improved clinical results, are most notable. The data, examined in terms of units transfused, are presented in Figure 17-1. Since the average adult hemophiliac in the United States receives 80,000 units of clotting factor per year, the best of the concentrates show safety over the equivalent of at least 10-human-years of treatment. Are the best of today's coagulation factor concentrates safe from the transmission of HBV, NANBHV (including HCV), and HIV. Given the limited number of patients eligible for clinical studies, and the length, difficulty, and expense of such studies, the best answer comes from a knowledge of the initial virus load coupled with information regarding virus removal, serendipitous inactivation, and intentional sterilization. A recently completed analysis of these factors (Horowitz 1990) indicates that the best of the modern coagulation factor concentrates are likely to be as safe as albumin (Figure 17-2).

Rehydration of lyophilised cartilage grafts sterilized by different methods

In in vitro experiments weight increase and rehydration speed of lyophilised cartilage grafts sterilized by different methods were determined. For periods of up to 72 h the increase in weight during rehydration was measured. The methods of sterilization used is only of little significance for such weight increase. Differences in rehydration speed clearly correlate with the initial weight of the lyophilised cartilage grafts. Smaller grafts are completely rehydrated after 5 to 6 h. This may explain the discrepancies in rehydration speed reported in the literature.

[Effects of different sterilizing techniques on osseous regeneration of grafted lyophilized cartilage]

The suitability of variably sterilized lyocartilage grafts as potential bone substitutes was investigated in animal experiments with special attention to configurational stability. In 3 Beagles corticocancellous implant beds were prepared by box-type ostectomies and lyophilized costal cartilage blocks sterilized with X-rays,ethylene oxide gas and beta-propriolactone solution were placed into them. Implants sterilized with X-rays and beta-propriolactone appeared to be unsuited for recontouring facial bone defects, since they showed complete loss of configuration after a follow-up time of 125 and 230 days, respectively. By contrast, cartilage implants sterilized with ethylene oxide gas retained their configuration after no less than 328 days. In light of these results, methods for sterilizing other biomaterials should be re-considered.

Use of betapropiolactone to disinfect fresh tissue without impairing antigenicity: method applicable to human immunodeficiency virus (HIV) positive tissue

A method for inactivating viruses in tissues is reported that does not impair the antigenicity of the Coxsackie virus or of some common tissue antigens, a common problem with standard tissue fixation methods. Tissues can be placed briefly in Betapropiolactone before cryostat sectioning without any adverse effect on preservation or antigen expression. It is suggested that use of Betapropiolactone is applicable to tissues harbouring or exposed to the human immunodeficiency virus (HIV). As betapropiolactone has been reported to be carcinogenic in rodents any potential danger can be avoided by basic simple precautions.

[Possible decontamination of pancreatin with gamma rays and chemical agents]

Certain pre-conditions given, the microbial contamination of pancreatin in powder form can be reduced below international standard values. However, each of the methods whether physical or chemical, causes a variable loss of activity depending on the methods applied and the concentration of the decontaminating agent used. Therefore during preparation of this complex enzymatic compound, highly aseptic conditions must be kept in all stages of the process to avoid an increase of germal contamination. For a final toxicological assessment of the decontaminated products, further tests are required.

Differences among available immunoglobulin preparations for intravenous use

Today almost all IgG preparations for intravenous use (IVIG) fulfill the basic requirements for a preparation given intravenously (sterility, pyrogenicity, antibody content but also anticomplementary activity, etc.). However, there are still marked differences among such preparations caused by the method of preparation: (1) Enzymatically treated IVIGs (by pepsin and plasmin) have a shorter biologic half-time and a disturbed IgG subclass composition; (2) in chemically treated IVIGs (beta-propiolactone, reduced or sulfonated IgGs) the IgG3 subclass is lacking and some of the Fc-related functions are altered; and (3) the IVIGs purified by anion exchangers are poor in the IgG4 subclass. The three main preparations sold in the United States (Gamimune N, Gammagard and Sandoglobulin) belong to the nonmodified preparations and, with the exception of the IgG subclass representation, show similar Fab- and Fc-related properties (antibody content, interaction with Fc receptors on monocytes, phagocytosis-promoting activity, etc.) In none of these preparations, an elevated level of undesired contaminants (prekallikrein activator, irregular anti-erythrocyte antibodies) are found.

[Monitoring of sterilization procedures for plasma derivatives using bacteriophages]

Since 1968 the combination of beta-propiolactone (beta-PL) plus UV-inactivation for the sterilization of plasma derivatives is in use at Biotest. In 1981, a bacteriophage test system was established for routine monitoring of the efficacy of this sterilization procedure, using the bacteriophages phi x 174, phi e, Kappa and f2. In the period of 1981 to 1986, 88 control experiments were performed under production conditions demonstrating a mean inactivation of these test viruses of greater than or equal to 6.7 log10. This constant and high efficacy of the beta-PL/UV sterilization procedure guarantees the longstanding safety of beta-PL/UV sterilized blood derivatives. Bacteriophages are also useful experimental viruses for monitoring the efficacy of pasteurization processes.

Characterization of a double avirulent mutant of rabies virus and its potency as a vaccine, live or inactivated

A strain bearing two mutations which abolish the virulence for adult animals after intracerebral or intramuscular inoculation has been constructed from the CVS strain of rabies virus. This apathogenic phenotype is stable after three successive passages of the double mutant in suckling mice brain. Trials of vaccination performed on mice in parallel with the double mutant and CVS both inactivated with beta-propiolactone indicate that the mutant is at least as efficient as CVS. This strain has also been found to be efficient as a live virus vaccine.

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.

Behavior of differently sterilized allogenic lyophilized cartilage implants in dogs

The behavior of beta-propriolactone-sterilized, radiation-sterilized, and gas-sterilized lyophilized cartilage implants was histiologically investigated at various intervals up to 328 days. Beta-propriolactone-sterilized lyophilized cartilage implants were completely resorbed after 230 days and had only undergone partial osseous substitution. The radiation-sterilized lyophilized cartilage implants behaved similarly after 125 days. Despite partial resorption of the gas-sterilized lyophilized cartilage after 328 days, constant form was maintained and complete bony substitution of the resorbed regions had occurred in each case.

Effect of BPL on haemoglobin electrophoresis

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Effect of beta-propiolactone on blood group antibody detection

A panel of 50 blood group antibodies covering a range of blood group antigens has been tested in the presence of 0.25% beta-propiolactone as a possible means of reducing infectivity of high-risk HTLV III/HBsAg samples. 11/50 (22%) antibodies could not be detected by the indirect antiglobulin test, and 6/40 (15%) were undetectable by the two-stage papain technique.

The longevity of sterilized aortic valve homografts 1966-1972

Between 1966 and 1972 seventy-two adult patients underwent aortic valve replacement with unstented aortic valve homografts prepared by chemical beta-propiolactone sterilization and storage. There were 5 hospital deaths and 6 foreign patients are lost to follow-up. Of the remaining 61, there have been 7 late deaths. Thirty-one patients have needed re-operation and 6 of them died. To date, 13 patients still have their homografts--none take anticoagulants and endocarditis has not occurred. The technique for valve preparation is not currently used anywhere, but the results, especially with respect to freedom from endocarditis and from calcification compare most favourably with current methods. The relative freedom from calcification suggests that it may still have relevance to the problems of aortic and pulmonary valve replacement in children.

[Experimental reconstruction of flexor tendon injuries with a free transplant tendon-tendon sheath unit]

The authors, in their experiments on chickens, imitate human "no man's land" flexor tendon injuries of bad prognosis. For reconstruction of gliding surfaces they transplanted composite flexor tendon grafts containing flexor tendons with their sheath, pulleys, and vincula. Autologous grafts were compared with homologous composite tendon grafts preserved in beta-propiolacton. Summarizing the results of macroscopic and light microscopic examinations they state that the tendon sheath of the autologous composite tendon grafts revitalize in two weeks, and their tissue structure remains practically intact. The composite tendon allografts conserved in beta-propiolacton on the contrary rebuild much more slowly, on the average over three months. Regeneration is accompanied by round-cell infiltration. In the case of the autogenous graft generally smaller, and in the case of homologous composite flexor tendon graft more multitudinous adhesions occurred between flexor tendon and tendon sheath. The authors conclude from the literature and their own results that the reconstruction of flexor tendons with autologous composite flexor tendon grafts is a proper method for the restoration of severe flexor tendon injuries. Before clinical use, homologous composite flexor tendon grafts require more experimental investigation.

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.

Preparation of complement fixation antigen of Chlamydia psittaci grown in tissue culture by treatment with beta-propiolactone

A new method of preparing a chlamydial complement fixation (CF) antigen by treatment with beta-propiolactone (BPL) is presented. Chlamydia psittaci strains Pigeon-1041 and Budgerigar-No. 1, and Chlamydia trachomatis strain L2/434/BU, propagated in L-929 cell monolayers, were inactivated with BPL. This BPL-treated antigen was useful for detecting CF antibodies in both human and pigeon sera, and it did not cause false-positive reactions, as are sometimes observed between some human sera and phenol-treated antigen derived from eggs. When this CF antigen was treated with potassium periodate and tested for reactivity with mouse immune ascitic fluid, it was found that the antigen contained type- or strain specificity as well as genus specificity. Immunization with the BPL-treated antigen elicited type- or strain-specific neutralizing antibody.

Inactivation of lymphadenopathy associated virus by chemical disinfectants

Reverse transcriptase activity of lymphadenopathy associated virus was assayed after exposure to various standard chemical disinfectants. 25% ethanol or 1% glutaraldehyde should prove sufficient to disinfect medical instruments, and 0.2% sodium hypochlorite for cleaning floors and benches. 0.1% formalin is too slow to be recommended.

In vitro alkylation of calf thymus DNA by acrylonitrile. Isolation of cyanoethyl-adducts of guanine and thymine and carboxyethyl-adducts of adenine and cytosine

Reaction of the rodent carcinogen acrylonitrile (AN) at pH 5.0 and/or pH 7.0 for 10 and/or 40 days with 2'-deoxyadenosine (dAdo), 2'-deoxycytidine (dCyd), 2'-deoxyguanosine (dGuo), 2'-deoxyinosine (dIno), N6-methyl-2'-deoxyadenosine (N6-Me-dAdo) and thymidine (dThd) resulted in the formation of cyanoethyl and carboxyethyl adducts. Adducts were not detected after 4 h. The adducts isolated were 1-(2-carboxyethyl)-dAdo (1-CE-dAdo), N6-CE-dAdo, 3-CE-dCyd, 7-(2-cyanoethyl)-Gua (7-CNE-Gua), 7,9-bis-CNE-Gua, imidazole ring-opened 7,9-bis-CNE-Gua, 1-CNE-dIno, 1-CE-N6-Me-dAdo and 3-CNE-dThd. Structures were assigned on the basis of UV spectra and electron impact (EI), chemical ionization (CI), desorption chemical ionization (DCI) and Californium-252 fission fragment ionization mass spectra. Evidence is presented which strongly suggests that N6-CE-dAdo was formed by Dimroth rearrangement of 1-CE-dAdo during the reaction between AN and dAdo. The carboxyethyl adducts resulted from initial cyanoethylation (by Michael addition) at a ring nitrogen adjacent to an exocyclic nitrogen atom followed by rapid hydrolysis of the nitrile moiety to a carboxylic acid. It was postulated that the facile hydrolysis is an autocatalyzed reaction resulting from the formation of a cyclic intermediate between nitrile carbon and exocyclic nitrogen. AN was reacted with calf thymus DNA (pH 7.0, 37 degrees C, 40 days) and the relative amounts of adducts isolated were 1-CE-Ade (26%), N6-CE-Ade (8%), 3-CE-Cyt (1%), 7-CNE-Gua (26%), 7,9-bis-CNE-Gua (4%), imidazole ring-opened 7,9-bis-CNE-Gua (19%) and 3-CNE-Thy (16%). Thus a carcinogen once adducted to a base in DNA was shown to be subsequently modified resulting in a mixed pattern of cyanoethylated and carboxyethylated AN-DNA adducts. Three of the adducts (1-CE-Ade, N6-CE-Ade and 3-CE-Cyt) were identical to adducts previously reported by us to be formed following in vitro reaction of the carcinogen beta-propiolactone (BPL) and calf thymus DNA. The results demonstrate that AN can directly alkylate DNA in vitro at a physiological pH and temperature.

Rabies vaccine prepared from the virus grown in Japanese quail embryo cell cultures

Fixed rabies virus strain MNIIVP-74 was grown in Japanese quail embryo cell cultures, concentrated by ultrafiltration and inactivated with beta-propiolactone. The resulting vaccine was markedly antigenic and immunogenic for laboratory animals. Human volunteers injected with 2.0 ml vaccine on days 0, 3, 7, 14, 30 and 90 exhibited more intensive and longer antibody production than those injected daily for 14 days.