Bacterial activity in cystic fibrosis lung infections

BACKGROUND: Chronic lung infections are the primary cause of morbidity and mortality in Cystic Fibrosis (CF) patients. Recent molecular biological based studies have identified a surprisingly wide range of hitherto unreported bacterial species in the lungs of CF patients. The aim of this study was to determine whether the species present were active and, as such, worthy of further investigation as potential pathogens. METHODS: Terminal Restriction Fragment Length Polymorphism (T-RFLP) profiles were generated from PCR products amplified from 16S rDNA and Reverse Transcription Terminal Restriction Fragment Length Polymorphism (RT-T-RFLP) profiles, a marker of metabolic activity, were generated from PCR products amplified from 16S rRNA, both extracted from the same CF sputum sample. To test the level of activity of these bacteria, T-RFLP profiles were compared to RT-T-RFLP profiles. RESULTS: Samples from 17 individuals were studied. Parallel analyses identified a total of 706 individual T-RF and RT-T-RF bands in this sample set. 323 bands were detected by T-RFLP and 383 bands were detected by RT-T-RFLP (statistically significant; P ≤ 0.001). For the group as a whole, 145 bands were detected in a T-RFLP profile alone, suggesting metabolically inactive bacteria. 205 bands were detected in an RT-T-RFLP profile alone and 178 bands were detected in both, suggesting a significant degree of metabolic activity. Although Pseudomonas aeruginosa was present and active in many patients, a low occurrence of other species traditionally considered to be key CF pathogens was detected. T-RFLP profiles obtained for induced sputum samples provided by healthy individuals without CF formed a separate cluster indicating a low level of similarity to those from CF patients. CONCLUSION: These results indicate that a high proportion of the bacterial species detected in the sputum from all of the CF patients in the study are active. The widespread activity of bacterial species in these samples emphasizes the potential importance of these previously unrecognized species within the CF lung

Culture Enriched Molecular Profiling of the Cystic Fibrosis Airway Microbiome

The microbiome of the respiratory tract, including the nasopharyngeal and oropharyngeal microbiota, is a dynamic community of microorganisms that is highly diverse. The cystic fibrosis (CF) airway microbiome refers to the polymicrobial communities present in the lower airways of CF patients. It is comprised of chronic opportunistic pathogens (such as Pseudomonas aeruginosa) and a variety of organisms derived mostly from the normal microbiota of the upper respiratory tract. The complexity of these communities has been inferred primarily from culture independent molecular profiling. As with most microbial communities it is generally assumed that most of the organisms present are not readily cultured. Our culture collection generated using more extensive cultivation approaches, reveals a more complex microbial community than that obtained by conventional CF culture methods. To directly evaluate the cultivability of the airway microbiome, we examined six samples in depth using culture-enriched molecular profiling which combines culture-based methods with the molecular profiling methods of terminal restriction fragment length polymorphisms and 16S rRNA gene sequencing. We demonstrate that combining culture-dependent and culture-independent approaches enhances the sensitivity of either approach alone. Our techniques were able to cultivate 43 of the 48 families detected by deep sequencing; the five families recovered solely by culture-independent approaches were all present at very low abundance (<0.002% total reads). 46% of the molecular signatures detected by culture from the six patients were only identified in an anaerobic environment, suggesting that a large proportion of the cultured airway community is composed of obligate anaerobes. Most significantly, using 20 growth conditions per specimen, half of which included anaerobic cultivation and extended incubation times we demonstrate that the majority of bacteria present can be cultured

Airway Microbiota and Pathogen Abundance in Age-Stratified Cystic Fibrosis Patients

Bacterial communities in the airways of cystic fibrosis (CF) patients are, as in other ecological niches, influenced by autogenic and allogenic factors. However, our understanding of microbial colonization in younger versus older CF airways and the association with pulmonary function is rudimentary at best. Using a phylogenetic microarray, we examine the airway microbiota in age stratified CF patients ranging from neonates (9 months) to adults (72 years). From a cohort of clinically stable patients, we demonstrate that older CF patients who exhibit poorer pulmonary function possess more uneven, phylogenetically-clustered airway communities, compared to younger patients. Using longitudinal samples collected form a subset of these patients a pattern of initial bacterial community diversification was observed in younger patients compared with a progressive loss of diversity over time in older patients. We describe in detail the distinct bacterial community profiles associated with young and old CF patients with a particular focus on the differences between respective “early” and “late” colonizing organisms. Finally we assess the influence of Cystic Fibrosis Transmembrane Regulator (CFTR) mutation on bacterial abundance and identify genotype-specific communities involving members of the Pseudomonadaceae, Xanthomonadaceae, Moraxellaceae and Enterobacteriaceae amongst others. Data presented here provides insights into the CF airway microbiota, including initial diversification events in younger patients and establishment of specialized communities of pathogens associated with poor pulmonary function in older patient populations

Brothers and sisters in China: no longer the one-child family

Following the end of the one-child-policy in China in 2016 and the gradual relaxation of only-one child per family in selected areas prior to that, family composition and relationship dynamics, especially siblings relationship within the Chinese familial context has gone through a rapid growth and some significant changes as a result of the introduction of the two-child policy. This policy change, with the possibility of adding another child into the family may have profound implications on the family system, its functioning and care relations among those living in China (Chen in The second child: Family transition and adjustment. Shanghai Educational Publishing House, Shanghai, China, 2018). First, this chapter considers the existing studies related to Chinese familial culture within the context of its population policy that has dominated family life in China in the past three decades. This chapter will then review empirical findings on role of Chinese parents in the development of sibling's relationships such as sibling conflict and social comparison; how their co-parenting behaviour and personal siblings experience may hinder or promote better siblings' relations. The chapter will also draw on existing research findings on the adaptation and adjustments of Chinese firstborn children during this transition into siblinghood. Finally, the chapter summarises and discusses the unique characteristics of sibling relationships within the Chinese context and its implication for family dynamics and the development of the new generation in China. Themes for future investigation are also suggested

Biološki učinci mikrotalasnog zračenja

In this paper the authors review the results of own clinical and experimental studies. Clinical examinations of 500 radar operators and matched controls showed no typical cases of »microwave sickness«. The studies on experimental animals pointed out the presence of considerable thermal effects, but only after high doses of microwave radiation.Iznose se sumarni rezultati istraživanja mikrotalasnog zračenja na profesionalno eksponovanim ljudima i na eksperimentalnim životinjama. Klinička ispitivanja provođena su tokom 10-godišnjeg perioda na 500 radarskih operatera i na kontrolnoj grupi od 350 radnika odgovarajuće dobi, pola i ostalih relevantnih parametara. Klinička i laboratorijska ispitivanja nisu pokazala pojave mikrotalasne bolesti, premda su pojedina radna mesta bila jako eksponovana. U eksperimentima na životinjama štakori i kunići eksponovani su različitim dozama zračenja (1-100 mW/cm2) tokom više časova, dana ili meseci. Osim termalnog opšteg učinka izazvanog velikim dozama zračenja, utvrđene su i kataraktogene promene u eksperimentalnih životinja