Maturation of nasal microbiota and antibiotic exposures during early childhood: a population-based cohort study.

OBJECTIVES: Little is known about maturation of the airway microbiota during early childhood and the consequences of early-life antibiotic exposure. METHODS: In a population-based birth cohort of 902 healthy Finnish children, we applied deep neural network models to investigate the relationship between the nasal microbiota (measured by 16S rRNA gene sequencing at up to three time points) and child age during the first 24 months. We also performed stratified analyses according to antibiotic exposure during the age period 0-2 months. RESULTS: The dense deep neural network analysis successfully modelled the relationship between 232 bacterial genera and child age with a mean absolute error of 4.3 (95%CI 4.0-4.7) months. Similarly, the recurrent neural network analysis also successfully modelled the relationship between 215 genera and child age with a mean absolute error of 0.45 (95%CI 0.42-0.47) months. Among the genera, Staphylococcus spp. and members of the Corynebacteriaceae decreased with age, while Dolosigranulum and Moraxella increased with age in the first 2 years of life (all false discovery rate (FDR) = 0.001). In children without early-life antibiotic exposure, Dolosigranulum increased with age (FDR = 0.001). By contrast, in those with early-life antibiotic exposure, Haemophilus increased with age (FDR = 0.002). CONCLUSIONS: In this prospective birth cohort of healthy children, we demonstrated the development of the nasal microbiota, with shifts in specific genera constituting maturation, in the first 2 years of life. Antibiotic exposures during early infancy were related to different age-discriminatory bacteria.

Interference between respiratory syncytial virus and rhinovirus in respiratory tract infections in children.

An acute viral respiratory tract infection might prevent infections by other viruses because of the antiviral innate immune response. However, with the use of PCR methods, simultaneous detection of two or more respiratory viruses is frequent. We analysed the effect of respiratory syncytial virus (RSV) infection on the occurrence of simultaneous rhinovirus (RV) infection in children within a birth cohort study setting. We used PCR for virus detection in nasal swabs collected from children with an acute respiratory tract infection at the age of 0-24 months and from healthy control children, who were matched for age and date of sample collection. Of 226 children with RSV infections, 18 (8.0%) had co-infections with RV, whereas RV was detected in 31 (14%) of 226 control children (p 0.049 by chi-square test). Adjustment for sex, number of siblings and socio-economic status strengthened the negative association between RSV and RV (OR 0.46, 95% CI 0.24-0.90; p 0.02). The median durations of symptoms (cough, rhinorrhoea, or fever) were 11 days in children with single RSV infections and 14 days in children with RSV-RV co-infections (p 0.02). Our results suggest that the presence of RSV reduces the probability of RV infection, but that, if a co-infection occurs, both viruses cause clinical symptoms.

Ca(2+) -activated K(+) current is essential for maintaining excitability and gene transcription in early embryonic cardiomyocytes.

AIM: Activity of early embryonic cardiomyocytes relies on spontaneous Ca(2+) oscillations that are induced by interplay between sarcoplasmic reticulum (SR) - Ca(2+) release and ion currents of the plasma membrane. In a variety of cell types, Ca(2+) -activated K(+) current (IK(Ca) ) serves as a link between Ca(2+) signals and membrane voltage. This study aimed to determine the role of IK (Ca) in developing cardiomyocytes. METHODS: Ion currents and membrane voltage of embryonic (E9-11) mouse cardiomyocytes were measured by patch clamp; [Ca(2+) ]i signals by confocal microscopy. Transcription of specific genes was measured with RT-qPCR and Ca(2+) -dependent transcriptional activity using NFAT-luciferase assay. Myocyte structure was assessed with antibody labelling and confocal microscopy. RESULTS: E9-11 cardiomyocytes express small conductance (SK) channel subunits SK2 and SK3 and have a functional apamin-sensitive K(+) current, which is also sensitive to changes in cytosolic [Ca(2+) ]i . In spontaneously active cardiomyocytes, inhibition of IK (Ca) changed action and resting potentials, reduced SR Ca(2+) load and suppressed the amplitude and the frequency of spontaneously evoked Ca(2+) oscillations. Apamin caused dose-dependent suppression of NFAT-luciferase reporter activity, induced downregulation of a pattern of genes vital for cardiomyocyte development and triggered changes in the myocyte morphology. CONCLUSION: The results show that apamin-sensitive IK (Ca) is required for maintaining excitability and activity of the developing cardiomyocytes as well as having a fundamental role in promoting Ca(2+) - dependent gene expression.

Serum endostatin levels are elevated in colorectal cancer and correlate with invasion and systemic inflammatory markers.

BACKGROUND: Endostatin, a fragment of collagen XVIII, is an endogenous angiogenesis inhibitor with anti-tumour functions. However, elevated circulating endostatin concentrations have been found in several human cancers including colorectal cancer (CRC). METHODS: Serum endostatin levels were measured by enzyme-linked immunoassay from a series of 143 patients with CRC and from 84 controls, and correlated with detailed clinicopathological features of CRC, serum leukocyte differential count and C-reactive protein (CRP) levels. RESULTS: Patients with CRC had higher serum endostatin levels than the controls (P=0.005), and high levels associated with age, tumour invasion through the muscularis propria and poor differentiation, but not with metastases. Endostatin levels showed a positive correlation with the markers of systemic inflammatory response and a negative correlation with the densities of tumour-infiltrating mast cells and dendritic cells. Collagen XVIII was expressed in tumour stroma most strikingly in blood vessels and capillaries, and in the muscle layer of the bowel wall. CONCLUSIONS: Elevated endostatin levels in CRC correlate with systemic inflammation and invasion through the muscularis propria. Increased endostatin level may be a result of invasion-related cleavage of collagen XVIII expressed in the bowel wall. The negative correlations between serum endostatin and intratumoural mast cells and immature dendritic cells may reflect angiogenesis inhibition by endostatin.

Endothelin-1 signalling controls early embryonic heart rate in vitro and in vivo.

AIM: Spontaneous activity of embryonic cardiomyocytes originates from sarcoplasmic reticulum (SR) Ca(2+) release during early cardiogenesis. However, the regulation of heart rate during embryonic development is still not clear. The aim of this study was to determine how endothelin-1 (ET-1) affects the heart rate of embryonic mice, as well as the pathway through which it exerts its effects. METHODS: The effects of ET-1 and ET-1 receptor inhibition on cardiac contraction were studied using confocal Ca(2+) imaging of isolated mouse embryonic ventricular cardiomyocytes and ultrasonographic examination of embryonic cardiac contractions in utero. In addition, the amount of ET-1 peptide and ET receptor a (ETa) and b (ETb) mRNA levels were measured during different stages of development of the cardiac muscle. RESULTS: High ET-1 concentration and expression of both ETa and ETb receptors was observed in early cardiac tissue. ET-1 was found to increase the frequency of spontaneous Ca(2+) oscillations in E10.5 embryonic cardiomyocytes in vitro. Non-specific inhibition of ET receptors with tezosentan caused arrhythmia and bradycardia in isolated embryonic cardiomyocytes and in whole embryonic hearts both in vitro (E10.5) and in utero (E12.5). ET-1-mediated stimulation of early heart rate was found to occur via ETb receptors and subsequent inositol trisphosphate receptor activation and increased SR Ca(2+) leak. CONCLUSION: Endothelin-1 is required to maintain a sufficient heart rate, as well as to prevent arrhythmia during early development of the mouse heart. This is achieved through ETb receptor, which stimulates Ca(2+) leak through IP3 receptors.

Familial breast cancer screening reveals an alteration in the RAP80 UIM domain that impairs DNA damage response function.

Germline mutations in two major susceptibility genes, BRCA1 and BRCA2, account for nearly 20% of familial breast cancers. A majority of the remaining genetic factors involved in heritable breast cancer susceptibility are, however, unknown. Recently, a new BRCA1-interacting protein, receptor associated protein 80 (RAP80), was identified. RAP80 plays an important role in BRCA1-mediated DNA damage responses (DDRs) by recruiting BRCA1 to DNA double-strand breaks (DSBs). A comprehensive screening of DNA from affected index cases of 112 BRCA1/BRCA2 mutation-negative Finnish breast cancer families revealed altogether 10 alterations in RAP80, one of which, c.241-243delGAA, resulted in a single glutamic acid deletion at residue 81 in a highly conserved region of ubiquitin interaction motif 1. The resultant delE81 protein product displayed significantly reduced ubiquitin binding and DSB localization. Expression of the RAP80 delE81 allele impaired both BRCA1 and ABRA1 DSB recruitment, thus compromising BRCA1-mediated DDR signaling. Compared with wild-type RAP80, expression of the delE81 allele was associated with a significant increase in cytogenetically detectable chromosomal aberrations, particularly chromatid breaks. Although evidently quite rare, these results suggest that critical constitutional mutations in RAP80 abrogate DDR function and may be involved in genetic predisposition to cancer.

Nordic collaborative study of the BARD1 Cys557Ser allele in 3956 patients with cancer: enrichment in familial BRCA1/BRCA2 mutation-negative breast cancer but not in other malignancies.

BACKGROUND: BARD1 was originally identified as a BRCA1-interacting protein but has also been described in tumour-suppressive functions independent of BRCA1. Several studies have indicated that the BARD1 gene is a potential target for germline changes predisposing to breast and ovarian cancer. The C-terminal Cys557Ser change has previously been uncovered to associate with an increased risk of breast cancer and was recently shown to result in defective apoptotic activities. AIM AND METHODS: Conformation-sensitive gel electrophoresis, minisequencing, TaqMan assays, denaturing high-performance liquid chromatography analysis and DNA sequencing were used to investigate the prevalence of the Cys557Ser allele in a large Nordic case-control study cohort consisting of 2906 patients with breast or ovarian cancer, 734 with prostate cancer, 188 with colorectal cancer, 128 men with breast cancer, and 3591 controls from Finland, Iceland, Denmark, Sweden and Norway. RESULTS: The frequency of the BARD1 Cys557Ser variant seemed to increase among patients from families with breast or ovarian cancer lacking BRCA1 or BRCA2 mutations: a significant difference was obtained compared with controls (6.8% v 2.7%; p<0.001; odds ratio (OR) 2.6; 95% confidence interval (CI) 1.7 to 4.0) and with patients from BRCA1/BRCA2 mutation-positive families (6.8% v 2.2%; p = 0.01; OR 3.2; 95% CI 1.2 to 8.3). In contrast, no major association with male breast, ovarian, colorectal or prostate cancer was observed. Additionally, a novel BARD1 allele resulting in Ser558Pro was identified in familial breast cancer cases. CONCLUSION: These results provide further evidence that BARD1 Cys557Ser confers a slightly increased risk of breast cancer in women.

Plasma enterolactone or intestinal Bifidobacterium levels do not explain adenoma formation in multiple intestinal neoplasia (Min) mice fed with two different types of rye-bran fractions.

The study was designed to evaluate whether two types of rye-bran fractions result in distinct bifidogenic effect or enterolactone production in multiple intestinal neoplasia (Min) mice and whether these parameters are associated with intestinal tumorigenesis in this animal model. The experimental diets were a non-fibre diet (control), a rye-bran diet, and diets containing either the soluble extract or the insoluble fraction prepared from rye bran. The main result on adenoma formation in these experiments was the observation that the soluble extract increased number (P=0.012) and size (P=0.008) of adenomas in the distal small intestine when compared with the non-fibre group. All rye-supplemented diets supported similarly the in vivo growth of Bifidobacterium (10(8)-10(9) colony forming units/g) in Min mice, whereas the non-fibre diet lowered intestinal Bifidobacterium below the level of detection. The results show that water solubility does not affect the bifidogenicity of rye bran. Mean plasma enterolactone concentration was highest in the rye-bran group (30.0 nmol/l; P=0.002), which along with the soluble-extract group (16.2 nmol/l; P=0.024) differed significantly from the non-fibre diet group (7.5 nmol/l). Thus, the mice fed with the rye bran were the best enterolactone producers. In conclusion, rye bran and rye fractions influence adenoma formation in Min mice to a varying degree but plasma enterolactone levels or the production of bifidogenic bacteria do not mediate the effect.

No evidence of involvement of germline BACH1 mutations in Finnish breast and ovarian cancer families.

Recently BACH1, a novel putative DNA helicase mapping to chromosome 17q22, was reported to interact specifically with BRCA1, and was suggested to be a candidate gene for predisposition to breast and ovarian cancers. Here, we screened 214 breast and ovarian cancer patients from 151 Finnish families for germline BACH1 mutations by utilising conformation-sensitive gel electrophoresis (CSGE) and genomic sequencing analysis. Four sequence alterations were observed in the exon regions of BACH1, three of which have been previously reported and were classified as polymorphisms. In 1 patient, a novel heterozygous 3101C>T variant was observed resulting in a proline to leucine substitution at codon 1034 (Pro1034Leu). This amino acid change occurs in the BRCA1 binding domain of the BACH1 protein. Although the 3101C>T transition was also found in one of the 304 control individuals with an unknown cancer status, it still remains possible that this alteration could represent a rare disease-related allele in the population. Functional assays are needed to resolve the biological significance of this novel BACH1 missense variant. Altogether, the available data suggest that germline mutations in BACH1 are extremely rare.