Multiplicity reactivation of vaccinia virus particles treated with nitrogen mustard

The nitrogen mustard bis(beta-chloroethyl)methylamine, a radiomimetic alkylating agent, is known for its ability to inactivate viruses in general and poxvirus in particular. These experiments show that vaccinia virus is rapidly inactivated by it. They show, in addition, that the treated virus exhibits multiplicity reactivation in L cells, closely resembling that experienced with the same virus after exposure to ultraviolet rays. These findings have come from observations of plaque titer, on the one hand, and virus particle aggregation (measured in the electron microscope), on the other. The titer of the treated virus is very sensitive to particle aggregation, increasing and decreasing in a reversible manner as the degree of clumping among the particles is changed. The magnitude of these changes is such that they must be considered in any situation involving plaque assay of the fraction of virus surviving treatment with nitrogen mustard.

Electron microscopy of monkey kidney cell cultures infected with rubella virus

Two rubella virus strains isolated in this laboratory were investigated in terms of their growth in LLC-MK(2) cell cultures and their effect on cell morphology. Rubella virus grew readily in LLC-MK(2) cells, but cytopathic effects of the virus were not observed in infected cultures. Such infected cultures can be subcultured indefinitely and continue to shed virus. Examination of rubella-infected cell cultures by electron microscopy showed the presence of annulate lamellae in the cytoplasm of 15% of the cells. No changes were evident in the nuclei. These membranous inclusions varied in complexity from parallel arrays of annulate lamellae to large lamellar structures of complex morphology. An occasional cell contained a crystal lattice structure in association with the lamellae. Larger inclusions, consisting of disorganized arrays of "unit" membranes, were also found. Uninfected cells were devoid of annulate lamellae, crystals, and complex membranous inclusions. No viruslike particles were observed in any part of the cells from infected cultures. The significance of the structures observed has not been determined.

Physical properties of human Mycoplasma species

Kim, Kwang S. (University of North Carolina, Chapel Hill), Wallace A. Clyde, Jr., and Floyd W. Denny. Physical properties of human mycoplasma species. J. Bacteriol. 92:214-219. 1966.-Studies were made of the comparative morphology and stability of five Mycoplasma species of human origin (M. hominis type 1, M. salivarium, M. fermentans, M. pneumoniae, M. pharyngis). Broth-cultivated organisms were examined by electron microscopy to determine their relative appearance after uniform processing, including fixation-drying with formaldehyde vapor. M. pneumoniae was characterized by the occurrence of 250- to 300-mmu spheres in clusters, and M. pharyngis by the appearance of filaments 120 mmu by 1.5 to 8 mu; the remaining species revealed a variety of structures, including spheres, rings, and short filaments. To complement these findings, the effect of physical stresses on viability of the mycoplasmas was measured by exposing the organisms to heat (in saline), osmotic variations (in sucrose), and sonic oscillation and repetitive freeze-thawing (in culture medium). M. pneumoniae was most resistant to heat, vibration, and freeze-thawing; M. pharyngis was most sensitive to heart and vibration, but was least affected by osmotic changes. The remaining organisms assumed intermediate positions. The type-related variations in relative morphology and stability suggest differing physical attributes of the mycoplasmas studied, supporting taxonomic differentiation of the five species based on metabolic and immunological criteria.

Tension Cavity

The concept of the tension cavity is relatively recent. The purpose of the present report is to emphasize the frequency of tension cavities in c1inical tube1'culòsis and to stress the role of endobronchial obstruction in the causation of such cavities. The tension cavities are often encountered in pulmonary tuberculosis.The cavities are caused by a check-valve mechanism resulting chiefly from two factors: an organic bronchial obstruction or a mechanical bronchial obstruction.Ten cases of tension cavity were presented. It was exclusively predominant in male, in relatively young adults.Obliteration or marked reduction of the tension cavities occurred in 2 to 9 weeks.The cavities of eight cases located in upper lung field, while the remainders located in middle lung field.The size of cavities were within 4cm, all but one which was 4.2cm. in diameter. The 6 cases were infectious.About 60 percent of tension cavity patients had blood-streaked sputum or hemoptysis. Chest pain was recorded in four cases. All but two cases had elevated ESR. AIl cases gained favorable, dramatic results with the rest and the effective anti-tuberculous chemotherapy.

Tobacco Smoking and Lung Cancer in Korea

Thi s is the result of statistical observation of 52 male and 5 female patients of primary lung cancer who visited Seoul University Hospital for past 7 years(1954 -1961).1. Primary Iung cancer was found most frequently in males of age 51 to 60 years.(22 of 52 cases, 42. 3 percent)2. Smokers possess about a twelve-fold greater chance of becoming afflicted with lung cancer than nonsmokers.3. In adults without cancer 80 percent of males and 20 percent of females were smokers in Seoul.

Investigations in Tuberculin Production: Part 1: The amount of tuberculoprotein obtained on different media, Part 2: Comparition between the amount of tuberculin obtained from culture filtrate and by extraction of tubercle bacilli cultured on three differ

Glyccrine broth and some synthctic mcdia, including those commonly used for tuberculin production, were compared in the following way. Three human starins were inoculated on to the media and after different incubation periods the weight of the culture, the pH and the protein content of the media was determined. Larger cops of bacteria were obtained on the synthetic media to the glycerine broth. Within the synthetic media differences were found as well in total growth as in the growth rate of the bacteria. Due to the natural content of proteins of glycerine broth, this medium could not compared with the synthetic media with regard to the amount of protein formed. Among the synthetic media Sauton medium had smaller protein content than the other media. For the full groun cultures no simple relation was found between the total crop of bacteria and the protein content of the culture filtrates. However, the cultures with a low pH(pH=4-5) had a lower protein content than the filtrates with a higher final pH. this may explain the small amount of protein obtained on Sauton medium, which had a low final pH. Some irregularities in the growth curves for one of the strains are supposed to be due to dissociation of the strain.Two strains of human tubercle bacilli were cultured for 4 weeks and 8 weeks on glycerine broth. Sauton medium and on Lind b II medium which is an enriched Sauton medium. After heat sterilisation of the cultures, the bacterial cells were extracted with 0.05 N sodium hydroxide. The amount of protein extracted and the cutancous activity of the extracts were compared with the protcin content and the biological activity of the corresponding culture filtrates. Large amounts of protcins were extracted from the cells but the biological activity of the extracts was low. In average the activity of the extracts was 10 times smaller than the activity of the culture filtrates. When regarded as a whole more tuberculin was obtained in Lind b II medium than in glycerine broth and Sauton medium. Under varing experimental conditions more tuberculin was obtained after 8 weeks incubation than after 4 weeks incubation. The relatin of the amount of tubertculin obtained with the two strains depeded on the medium used for the comparison. For the extracts all the protein had the same biological activity. For the culture filtrate some of the protein had a higher activity than another part. Thus it was not justified to use the yield of protein as gause of the tuverculin in the culture filtratcs in the present experiment.