Changes in the Fungal Autoflora of Apollo Astronauts

Specimens were repeatedly obtained for mycological examination from the skin, throat, urine, and feces of the six astronauts who conducted the Apollo 14 and Apollo 15 lunar exploration missions. Analysis of preflight data demonstrates that the process of severely restricting opportunities from colonization for 3 weeks before flight resulted in a 50% reduction in the number of isolated species. Postflight data indicate that exposure to the space flight environment for up to 2 weeks resulted in an even greater reduction with a relative increase in the potential pathogen Candida albicans. No incidences of microbial shock were observed when crewmembers were quarantined for 16 days after completion of the space flight. Intercrew transfer of particular species could not be demonstrated because most species were not consistently recovered.     

Anaerobes in the upper respiratory tract in infancy

Development of the indigenous microbiota begins on the surfaces of the human body after birth when infants are exposed to continuous person-to-person and environmental contacts with microbes. Anaerobes constitute a significant part of indigenous bacterial communities at different body sites. Pioneering anaerobic commensals are able to colonize and survive in the oral cavity during the first months of life. After teeth emerge, more attachment sites and potential niches are available for anaerobic bacterial colonization. Specific partner relationships influence the composition and stability of forming multigeneric communities, biofilms, where Fusobacterium nucleatum is of specific interest. In infancy, the oral colonization seems to be rather stable at species level, though not at clonal level. The colonization pattern in the nasopharynx is different from that in the oral cavity; anaerobes are absent from healthy nasopharynges but transiently colonize this anatomical site during infection. The most plausible origin for nasopharyngeal anaerobes is the oral cavity and, conceivably, saliva is the most likely transmission vehicle. Whether anaerobic bacteria colonize the nasopharynx just because of ecological changes favoring their growth or whether they could play an active role in the pathogenesis of respiratory infections is not known.     

Microflora of the upper respiratory tract in young children under normal conditions and in respiratory tract diseases. Microbial count of the upper respiratory tract in healthy children and in children with pneumonia

The results of the inoculation of material taken from the anterior section of the nasal cavity and from the pharyngeal mucosa of 50 healthy young children and 298 acute pneumonia patients were analyzed. 23 microbial species were isolated. In the samples taken from the anterior section of the nasal cavity, monocultures were detected in 86 samples and 54 variants of associations including 2-4 species, in 139 samples. In the samples taken from the pharynx, monocultures were detected in 59 samples and 180 variants of associations including 2-6 species, in 282 samples. Differences in the contamination of the nasal cavity and the pharynx in healthy children and in pneumonia patients were revealed. These differences were manifested in the structure of the microflora (monocultures, associations, their composition), the assortment of microbial species and their concentration. In young children with pneumonia the microflora of the upper respiratory tract was found to reflect the severity of acute pneumonia and the intensity of the pathological process in the lungs (uncomplicated, pyodestructive pneumonia, pyodestructive pneumonia with fatal termination, acute purulent pleurisy).     

Flow simulation in the human upper respiratory tract

Computer simulations of airflow patterns within the human upper respiratory tract (URT) are presented. The URT model includes airways of the head (nasal and oral), throat (pharyngeal and laryngeal), and lungs (trachea and main bronchi). The head and throat morphology was based on a cast of a medical school teaching model; tracheobronchial airways were defined mathematically. A body-fitted three-dimensional curvilinear grid system and a multiblock method were employed to graphically represent the surface geometries of the respective airways and to generate the corresponding mesh for computational fluid dynamics simulations. Our results suggest that for a prescribed phase of breath (i.e., inspiration or expiration), convective respiratory airflow patterns are highly dependent on flow rate values. Moreover, velocity profiles were quite different during inhalation and exhalation, both in terms of the sizes, strengths, and locations of localized features such as recirculation zones and air jets. Pressure losses during inhalation were 30-35% higher than for exhalation and were proportional to the square of the flow rate. Because particles are entrained and transported within airstreams, these results may have important applications to the targeted delivery of inhaled drugs.     

Management of upper respiratory tract infections by telephone.

We surveyed Utah general internists (N = 134) regarding their attitudes toward and practices associated with telephone management of upper respiratory tract infections. The questionnaire contained 3 case vignettes--viral upper respiratory tract infection, streptococcal pharyngitis, and acute infectious epiglottitis--and a series of questions were asked about telephone diagnosis, management preferences (clinic versus telephone), and telephone management practices. The 53 respondents (40%) were able to make important diagnostic distinctions about upper respiratory tract infections from a written vignette. As the likelihood of a complicated or serious condition increased, patients would be appropriately triaged for clinical evaluation. Most internists would make a written record of the telephone conversation. Only 1 internist of the 53 would charge for telephone management.     

Microflora of the upper respiratory tract of normal young children and in respiratory tract diseases. Normal microflora and dysbiosis at different levels of the upper respiratory tract in healthy children and pneumonia patients

Material obtained from the mucous membranes of the upper respiratory tract (the anterior section of the nasal cavity, the fauces) in young children, both healthy and suffering with different forms of acute pneumonia, has been analyzed with due regard to the structure of the microflora, its specific composition and the size of populations formed by different species constituting the microflora. This analysis has made it possible to determine the species constituting normal microflora, to detect its dysbiotic changes, and to determine their degree (partial or complete dysbacteriosis). The degree of pathologic changes in the microecological balance of the upper respiratory tract has been shown to reflect the severity of acute pneumonia and to be determined by the characteristics of the natural resistance system in young children.     

Carcinogen: DNA adducts in tobacco smoke-associated cancer of the upper respiratory tract.

Mortality connected with tobacco smoke-associated laryngeal cancer in Poland markedly exceeds the relevant epidemiological data from other European countries. The main groups of genotoxic agents considered as potential carcinogens present in tobacco smoke are polycyclic aromatic hydrocarbons, aromatic amines, N-nitrosoamines and reactive oxygen species. Aromatic DNA adducts, N7-alkylated guanosines and oxidative DNA damage derived from tobacco smoke exposure were detected in laryngeal and oral (tumour and non-tumour) biopsies, and white blood cells of cancer subjects. Further, DNA lesions were analysed to estimate the significance of such confounders as intensity of smoking, subject's sex, age, topography of larynx, cancer staging and genetic factor. The number of cigarettes smoked per day was found to be the main determinant of an individual's DNA adduct level. The occurrence of DNA lesions was established as a reliable marker of former exposure to tobacco smoke genotoxicants. On the other hand, a comparison of DNA lesion levels in various regions of larynx indicates limited usefulness of DNA adduct analysis as an estimate of cancer risk. For a better risk estimation one has to take into account DNA lesions in proto-oncogenes and tumour suppressor genes and the efficacy of DNA repair. Altogether, DNA adducts formation and removal has to be considered as a single stage in the multistep carcinogenesis.