Effect of the presence of hardened erythrocytes on deformation-orientation characteristics of normal erythrocytes in shear flow studied by the spin label method.

The effect of the presence of hardened red blood cells (HRBC) in a mixed suspension on the deformation-orientation characteristics of normal cells in flow is experimentally probed by the electron spin resonance (ESR) spin label method, using a phosphatidylcholine label which does not transfer between the cells. The average deformation-orientation of the normal cells is generally suppressed by the presence of HRBC to different degrees, depending upon the shape and the way the HRBC are prepared. The effects are qualitatively explained by disturbance of laminar shear flow due to the random tumbling of the HRBC.

Susceptibility to rhinovirus infection in chronic bronchitis.

The role of rhinoviruses in chronic bronchitis was examined serologically in the community of Tecumseh, Michigan. Five different rhinovirus types had been identified by isolation to be present in the community during the time of the study. They were tested against serums obtained from persons with chronic bronchitis and matched control subjects. Both males and females with chronic bronchitis had more frequent infections than did the control subjects; for males, the differences were significant. The higher infection rate among the bronchitic subjects was not related to their being deficient in antibody at the start of the study. It was concluded that persons with chronic bronchitis appear to be more susceptible to rhinovirus infection, as they are to other viral pathogens.

The Tecumseh Study of Illness. XIV. Occurrence of respiratory viruses, 1976-1981.

During 1976-1981, surveillance of respiratory infection in Tecumseh, Michigan included isolation of respiratory viruses using methods similar to those employed in 1965-1971. As in the earlier period, influenza viruses continued to be isolated annually, but not without some changes in regularity of appearance. Parainfluenzaviruses also exhibited some marked changes in patterns of occurrence, but years of activity of parainfluenza types 1 and 2 were similar to those reported in other studies. Respiratory syncytial viruses continued to be limited in appearance to relatively brief periods. Rates of isolation of parainfluenzaviruses and respiratory syncytial viruses demonstrated their importance in reinfections of older children and adults. This was confirmed by examination of characteristics of associated illnesses.

The Tecumseh study of respiratory illness. VII. Further observations on the occurrence of respiratory syncytial virus and Mycoplasma pneumoniae infections.

The occurrence of infection with respiratory syncytial (RS) virus and Mycoplasma pneumoniae was determined over a 6-year period among residents of Tecumseh, Michigan by isolation and serology. RS virus infection was detected for a variable time each year during the months extending from November to May. There was little viral activity in intervals between these periods of prevalence, which occurred on an alternating short-long cycle. Higher infection rates were detected in periods preceding the long interval than were detected in periods preceding the short interval. Viruses isolated from serial annual outbreaks did not show any sequential changes in antigens, although some variation in antigenic structure was apparent. Infections were common in school-age children, indicating the role of this population in transmission. Young girls were infected as often as young boys, suggesting that observed differences in occurrence of illness must be related to differences in expression of infection. In contrast to RS virus, M. pneumoniae did not appear and disappear annually, but like it, the school-age group was most heavily involved in infection.

Relative efficacy of embryonated eggs and cell culture for isolation of contemporary influenza viruses.

The efficiency of embryonated eggs and primary monkey kidney cell culture for isolation of contemporary influenza viruses was compared over three seasons by parallel inoculation of clinical materials. For the type A (H1N1) strains of 1977-1978 and for type B strains eggs were very inefficient, and nearly all viruses were isolated in cell culture alone. For the type A (H1N1) strains of 1978-1979 and for type A (H3N2) strains, isolations were more frequently made in eggs, but even here eggs were not as efficient for primary isolation as were cell cultures. It is concluded that primary monkey kidney cell cultures can be used as the single system for primary isolation of current type A and B influenza viruses.

Rhinovirus infections in Tecumseh, Michigan: frequency of illness and number of serotypes.

We studied rhinovirus-associated illnesses from 1976 to 1981 among residents of the community of Tecumseh, Michigan, in a continuation of similar studies done in 1966-1971. Rhinoviruses were the most frequently isolated respiratory pathogen in all age groups, including young children. The pattern of age-specific isolation rates was similar to that for total respiratory illness. Rhinovirus-associated illnesses were generally mild but of relatively long duration; restriction of daily activity was frequent, especially in certain age groups. Typing of all isolates has been completed; with high-quality antisera nearly all isolates could be typed. Thus, new serotypes are probably not evolving, and most have already been identified. Differences in frequency of occurrences of different serotypes were evident, but ranking in order of importance was difficult based on existing data.

Controlled trial of enviroxime against natural rhinovirus infections in a community.

The therapeutic effect of intranasally administered enviroxime was tested against naturally occurring common colds. The double-blind evaluation was carried out in Tecumseh, Mich., during a period when rhinoviruses are usually the principal pathogen. Rhinovirus transmission followed the typical pattern during this period of study. Although there were trends indicating greater therapeutic effectiveness for enviroxime when certain nasal symptoms were considered, there were no consistent statistically significant differences between treated and untreated groups. Results were unchanged when illnesses in different periods or associated with rhinovirus isolation were examined. It was concluded that no therapeutic effect of enviroxime was demonstrated.