Quantitative Studies on Fabrics as Disseminators of Viruses: I. Persistence of Vaccinia Virus on Cotton and Wool Fabrics

The persistence of vaccinia virus on wool (blanket and gabardine) and cotton (sheeting, terry cloth, and knit jersey) fabrics was studied. The fabrics were exposed to the virus by three methods: direct contact, aerosol, and virus-containing dust having a high content of textile fibers. Fabrics exposed to virus by each method were held in 35 and 78% relative humidities at 25 C. Virus was recovered for up to 14 weeks from wool fabrics exposed to virus and held in the low humidity. In contrast, virus persisted for shorter periods of time on the cotton fabrics. No virus was detected on terry cloth as early as 3 days after exposure to virus. The virus appeared to be less stable in the high humidity, and the method of exposure of the fabrics to virus apparently had an effect upon the persistence of the agent. On all fabrics, viral persistence was of sufficient duration to be of epidemiological significance.     

Quantitative Studies on Fabrics as Disseminators of Viruses: II. Persistence of Poliomyelitis Virus on Cotton and Wool Fabrics

The length of time that poliovirus could be recovered from wool gabardine and blanket, and from cotton sheeting, terry cloth, and knit jersey fabrics was determined under conditions of controlled temperature and humidity (25 C in 35 and 78% relative humidities). Three types of exposure of the fabrics to viruses were used: direct contact, aerosol, and virus-containing household dust having a high content of textile fibers. When held in 35% relative humidity, virus persisted for 20 weeks on wool fabrics, but only 1 to 4 weeks on cotton fabrics. At this relative humidity, virus titers on wool fabrics decreased rapidly to low but detectable levels which persisted for long periods of time, whereas in 78% relative humidity the decrease in virus titer was less rapid, but the period of viral persistence was shorter. Generally, virus titers on cotton fabrics held in both relative humidities decreased exponentially to an undetectable level. The method of exposure to virus had a definite effect on the duration of viral persistence on a given fabric. Virus contained in household dust was least stable.     

Quantitative Studies on Fabrics as Disseminators of Viruses: IV. Virus Transmission by Dry Contact of Fabrics

Cotton and woolen fabrics and fabrics of synthetic fibers were exposed by direct contact (pipette) and by aerosolization to poliovirus and to vaccinia virus in separate experiments, allowed to dry for 16 hr at 25 C in 35% relative humidity, and randomly tumbled with sterile swatches of the same fabrics for 30 min. By use of a HEp-2 cell assay system, up to 10^3.5 CCID₅₀ of poliovirus per ml and 10^4.4 CCID₅₀ of vaccinia virus per ml were recovered from the originally sterile fabrics as early as 1 to 10 min after contact. Maximum transfer of both viruses was achieved with wool blanket material, although high titers of vaccinia virus were recovered from all fabrics tested. Poliovirus placed on the fabrics in an aerosol tended to be transferred to the sterile fabrics at a greater rate than when it was placed on the fabrics by direct contact. The method of exposure had essentially no effect on the rate of transfer of vaccinia virus.     

Quantitative Studies on Fabrics as Disseminators of Viruses: V. Effect of Laundering on Poliovirus-Contaminated Fabrics

The effects of laundering with both anionic and nonionic detergents in cold, warm, and hot water on poliovirus-contaminated cotton sheeting, cotton terry cloth, washable wool shirting, wool blanketing, dull nylon jersey, and dacron/cotton shirting were determined. The fabrics were exposed to virus by aerosolization and direct contact (pipette) in separate studies. Although the results varied with each factor used in the study, virus titers on all the fabrics were generally reduced considerably by the laundering process. When the fabrics were dried for 20 hr after laundering, an additional decline in virus titers was seen, often to below detectable levels. The type of detergent used made little difference in effect on virus titer reduction, but the hot wash water markedly reduced the detectable virus. Fabric type was not a major factor in the majority of the experiments, although virus tended to be eliminated more readily from the nylon jersey, and in warm water the virus persisted longer on wool blanketing material laundered in anionic detergent. Sterile fabrics of each type laundered with similar fabrics which contained virus often became contaminated by the virus during the laundering process. Virus titers ranging from undetectable to 10(3.9) cell culture 50% infectious doses/ml were obtained from samples of the rinse water after warm- and cold-water laundering.     

Physical Studies on Pox Viruses: I. Inactivation of Vaccinia Virus Infectivity With Low-Energy Electrons

Vaccinia virus was irradiated in vacuo with low-voltage electrons of restricted ranges. It was found that the pock-forming ability of the virus was not decreased after bombardment with electrons penetrating 100 A beneath the virus surface. There was very slight reduction in titer with large doses of electrons penetrating 330 A, but a sudden marked drop in infectivity occurred after exposure to electrons penetrating 500 to 700 A. Electrons of higher energies, including those capable of penetrating the virus particle completely, did not produce significant further fall in infectivity titer. It is concluded that a highly radiation-sensitive unit essential for pock formation is situated 500 to 700 A beneath the surface of the virus particle, possibly in the form of a shell. The relation of this finding to the known structure of the virus and to other radiation data on the dimensions of the infectious unit is discussed.     

Use of a Recombinant Vaccinia Virus Expressing Interferon Gamma for Post-Exposure Protection against Vaccinia and Ectromelia Viruses

Post-exposure vaccination with vaccinia virus (VACV) has been suggested to be effective in minimizing death if administered within four days of smallpox exposure. While there is anecdotal evidence for efficacy of post-exposure vaccination this has not been definitively studied in humans. In this study, we analyzed post-exposure prophylaxis using several attenuated recombinant VACV in a mouse model. A recombinant VACV expressing murine interferon gamma (IFN-γ) was most effective for post-exposure protection of mice infected with VACV and ectromelia virus (ECTV). Untreated animals infected with VACV exhibited severe weight loss and morbidity leading to 100% mortality by 8 to 10 days post-infection. Animals treated one day post-infection had milder symptoms, decreased weight loss and morbidity, and 100% survival. Treatment on days 2 or 3 post-infection resulted in 40% and 20% survival, respectively. Similar results were seen in ECTV-infected mice. Despite the differences in survival rates in the VACV model, the viral load was similar in both treated and untreated mice while treated mice displayed a high level of IFN-γ in the serum. These results suggest that protection provided by IFN-γ expressed by VACV may be mediated by its immunoregulatory activities rather than its antiviral effects. These results highlight the importance of IFN-γ as a modulator of the immune response for post-exposure prophylaxis and could be used potentially as another post-exposure prophylaxis tool to prevent morbidity following infection with smallpox and other orthopoxviruses.     

In Vivo Antiviral Properties of Biologically Active Compounds: II. Studies with Influenza and Vaccinia Viruses

The in vivo anti-influenza virus and antivaccinia virus activity of 156 biologically active compounds was determined. One of two criteria was used for evaluating activity against the influenza virus. The criteria were increase in survivor number and mean survival time, and reduction in virus-induced lung consolidation in treated, infected Swiss mice. Increase in survivor number and mean survival time were the criteria for evaluation of antivaccinia virus activity. Several drug doses were tested against two virus concentrations to demonstrate antiviral activity more clearly. Two compounds were considered significantly active against the influenza virus: DL-noformicin (NSC 72942) and amantadine hydrochloride (NSC 83653). Eleven compounds had reproducible activity against vaccinia virus: isatin-beta-thiosemicarbazone (NSC 721), 6-azauracil (NSC 3425), 9-alpha-fluoro-2alpha-methylhydrocortisone 21-acetate (NSC 12601), 5-[bis(2-chloroethyl)amino]uracil (NSC 34462), 5-iodo-2'-deoxyuridine (NSC 39661), streptonigrin (NSC 45383), N-methylisatin beta-thiosemicarbazone (NSC 69811), cytovirin (NSC 91770), 9-beta-D-arabinofuranosyladenine (NSC 404241), and 5-(mercaptomethyl)uracil (NSC 529351).     

痘苗病毒诱导HeLa细胞的凋亡

痘苗病毒感染ＨｅＬａ细胞后形态学上出现了较典型的细胞凋亡特征,电泳分析显示出ＤＮＡ阶梯,用ＤＮＡ断裂原位检测技术发现其染色质断裂主要存在于核周,与染色质凝聚位置相似。     

Virucidal Effect of Sodium p-Chloromercuribenzoate on Influenza Viruses Attributable to Inhibition of Virus Particle-Associated RNA-Dependent RNA Polymerase

Sodium p-chloromercuribenzoate (PCMB) caused a noticeable reduction of infectivity of prototype strains of type A and Lee strain of type B influenza viruses at concentrations of 100 and 200 μg/ml, respectively, after an incubation at 37 C for 60 min. The virucidal effect on A/AA/2/60 (H₂N₂) strain was dependent on the concentration of the drug and temperature as well as on the time of incubation. The reagent exerted this effect at a concentration which induced little change in the hemagglutinating and neuraminidase activities of the virus. PCMB inhibited by 50% the virus particle-associated RNA polymerase activity of all prototype strains of type A influenza virus at about 2 μg/ml and that of Lee strain of type B influenza virus at 8.5 μg/ml. Other sulfhydryl reagent such as phenylmercuric nitrate also exhibited virucidal effect on A/AA/2/60 virus which paralleled their inhibition of the virus particle-associated RNA polymerase activity. From these results it was considered likely that the virucidal action of PCMB on influenza viruses was attributable to inhibition of the virus particle-associated RNA polymerase activity.     

应用痘苗病毒为载体表达人白细胞介素4的研究

在真核细胞中表达近似于人类天然糖基化的白细胞介素４（ｈＩＬ－４）,为重要的研究课题。利用基因工程技术,以痘苗病毒作为载体,使之在真核细胞中表达ｈＩＬ－４,为生产糖基化的ｈＩＬ－４开辟新的可能途径。在痘苗病毒表达载体ｐＪ１２０质粒的基础上,组建了含有ｈＩＬ－４基因的ｐＪｌ２０／ｈＩＬ－４重组质粒,该质粒以痘苗病毒的胸腺嘧啶核苷激酶（ＴＫ）基因为侧翼序列,中间插入痘苗病毒的Ｐ１１和Ｐ２５两个转录方向相反的启动子,Ｐ２５的下游连接β－半乳糖苷酶（ＬａｃＺ）基因,ｈＩＬ－４基因在痘苗病毒启动子Ｐ１１控制下进行表达,将ＰＪ１２０／ｈＩＬ－４质粒ＤＮＡ用脂质体转染法导入ＴＫ阴性的骨髓瘤细胞（ＴＫ１４３细胞）,与预先感染的痘苗病毒在细胞内进行同源序列重组,并且用病毒的核酸杂交鉴定证实,ｈＩＬ－４基因已重组到痘苗病毒基因组中,用ｈＩＬ－４应答细胞株检测病毒感染细胞上清,发现重组病毒感染的细胞上清中含有高滴度的ｈＩＬ－４活性,并对此种情况下ｈＩＬ－４产生的条件进行了动态观察。     

Studies on Papanicolaou staining. III. Quantitative investigations of orangeophilia and cyanophilia

This paper provides data derived from the visible light absorbance spectra of Papanicolaou stained epithelial cells from the uterine cervix. Twenty-four types of spectra have been considered, namely, those derived from orangeophilic and cyanophilic nuclei and cytoplasms of superficial, intermediate, parabasal and dysplastic cells, and cells of carcinoma in situ and invasive carcinoma. Wavelengths of maximum absorbance and peak absorbances are tabulated. The proportions of bound orange G, eosin Y, aluminum-hematein and light green SF yellowish have been calculated. For the majority of cell types, dyebinding differences between orangeophilic and corresponding cyanophilic substrates were statistically significant. CIE coordinates were calculated from absorbance spectra; again differences between organeophilic and cyanophilic cells were statistically significant in most cases. Although the designation of cells as orangeophilic or cyanophilic is made on the basis of cytoplasmic coloration, the nucleus is also usually orangeophilic or cyanophilic. These nuclear differences are real and not due to the effects of over- and underlying cytoplasm.     

Potentially Infectious Agents Associated with Shearling Bedpads: I. Effect of Laundering with Detergent-Disinfectant Combinations on Polio and Vaccinia Viruses

Glutaraldehyde-tanned woolskin pads which are used for the prevention of decubitus ulcers in bed patients were experimentally contaminated with polio or vaccinia viruses. Two methods of exposure, direct contact and aerosol, were used in separate experiments. Attempts were made to remove or inactivate these virus contaminants by laundering the woolskins in a quaternary ammonium disinfectant, a phenolic disinfectant, or alkalinized glutaraldehyde, in combination with an anionic detergent or a nonionic detergent. The effect of a commercial detergent-sanitizer was also studied. The virus titers were significantly reduced in all experiments, but only laundering in glutaraldehyde in combination with either detergent lowered the vaccinia virus titers to below detectable limits. High concentrations of glutaraldehyde altered the texture of the wool and leather apparently by precipitating a component of the detergent onto the fibers. In all the poliovirus experiments, the virus was still detectable on either or both the wool and the leather of the pads after laundering. The rinse water from each experiment was tested for the presence of virus. No vaccinia virus was recovered, but poliovirus was demonstrated in titers up to 10(3) cell culture 50% infectious doses.     

Studies on Papanicolaou Staining. III. Quantitative Investigations of Orangeophilia and Cyanophilia

This paper provides data derived from the visible light absorbance spectra of Papanicolaou stained epithelial cells from the uterine cervix. Twenty-four types of spectra have been considered, namely, those derived from orangeophilic and cyanophilic nuclei and cytoplasms of superficial, intermediate, parabasal and dysplastic cells, and cells of carcinoma in situ and invasive carcinoma. Wavelengths of maximum absorbance and peak absorbances are tabulated. The proportions of bound orange G, eosin Y, aluminum-hematein and light green SF yellowish have been calculated. For the majority of cell types, dyebinding differences between orangeophilic and corresponding cyanophilic substrates were statistically significant. CIE coordinates were calculated from absorbance spectra; again differences between orangeophilic and cyanophilic cells were statistically significant in most cases. Although the designation of cells as orangeophilic or cyanophilic is made on the basis of cytoplasmic coloration, the nucleus is also usually orangeophilic or cyanophilic. These nuclear differences are real and not due to the effects of over- and underlying cytoplasm.     

Studies of Nondefective Adenovirus 2-Simian Virus 40 Hybrid Viruses. VI. Characterization of the DNA from Five Nondefective Hybrid Viruses

Certain biophysical characteristics of the DNA from each of the five nondefective adenovirus 2 (Ad2)-simian virus 40 (SV40) hybrid viruses (Ad2(+)ND(1), Ad2(+)ND(2), Ad2(+)ND(3), Ad2(+)ND(4), Ad2(+)ND(5)) have been determined. The guanine plus cytosine content varied from 55 to 57% and was not significantly different from that of nonhybrid Ad2 (56%), and the hybrid DNA molecules had mean molecular lengths which were similar to that of the standard, Ad2. The Ad2 and SV40 components of each hybrid were linked by alkali-resistant, presumably covalent bonds. The percentage of SV40 DNA in each hybrid virus was determined by hybridization with SV40 complementary RNA in a calibrated system. The results indicate that each hybrid virus DNA contains a different percentage of SV40 nucleotide sequences. The estimated size of the SV40 DNA component varies from 48,000 daltons for Ad2(+)ND(3) to 840,000 daltons for Ad2(+)ND(4), the latter being equivalent to between one-fourth and one-third of the SV40 genome.     

Viruses of Entamoeba histolytica III. Properties of the Polyhedral Virus of the HB-301 Strain

Some biological characteristics and bioassay of a polyhedral virus isolated from normal-appearing strain HB-301 of Entamoeba histolytica are described. The virus produced lysis of susceptible strains of E. histolytica, yet it caused no cytopathological effect in the host strain, HB-301. The virus and host amoeba existed in an equilibrium; approximately 10(4) mean infective dose units of virus were produced per million HB-301 amoebae. Superinfection and antiviral antiserum treatment failed to disturb this equilibrium permanently. The mechanism of viral persistence in strain HB-301 amoebae remains to be determined. Purification of the virus was attempted. Ninety-nine percent of the viral infectivity was associated with a low-speed pellet which consisted of complexes of virus and cellular membranes. Various treatments of this low-speed pellet failed to release virus. Biologically active, membrane-free virus of low titer was prepared by differential centrifugation of supernatant solutions and employed in electron microscopy and other studies.