Developmental changes in functional connectivity between the prefrontal cortex and amygdala following fear extinction.

The amygdala and prefrontal cortex (PFC) undergo dramatic changes in structure, function, and regional connectivity in early life, ultimately stabilizing in early adulthood. Pathways between these two structures underlie many forms of emotional learning, including the extinction of conditioned fear. Here we sought to characterize changes in extinction-related medial PFC (mPFC) â†’ amygdala functional connectivity across development that might explain adolescent impairments in extinction. The retrograde tracer Fluorogold was infused into the amygdala of postnatal day (P)22-23 (juvenile), P31-32 (adolescent), or ≥ P69 (adult) rats, which were then exposed to fear conditioning and extinction training. Brains were collected following extinction or context exposure and processed for expression of pMAPK (as a marker of learning-dependent plasticity) in prelimbic (PL) and infralimbic (IL) amygdala-projecting neurons. Consistent with previous findings, amygdala-projecting mPFC neurons were located primarily in layers (L)II/III and V of the mPFC. We noted that mPFC LII/III projected predominantly to the ipsilateral basolateral amygdala, whereas LV projected bilaterally and targeted multiple amygdalar nuclei. Extinction was not associated with changes in extinction-related plasticity in the PL-amygdala pathways in any age group. No changes were seen in LII/III of the IL, but extinction-related plasticity in LV amygdala-projecting IL neurons decreased linearly across development. These findings suggest that extinction-related functional connectivity between the IL and the amygdala undergoes fundamental changes across development that may contribute to alterations in fear suppression across development.

Distinctive gut microbiomes of ankylosing spondylitis and inflammatory bowel disease patients suggest differing roles in pathogenesis and correlate with disease activity.

BACKGROUND: Multiple studies have confirmed dysbiosis in ankylosing spondylitis (AS) and inflammatory bowel disease (IBD); however, due to methodological differences across studies, it has not been possible to determine if these diseases have similar or different gut microbiomes. RESULTS: In this study, faecal and intestinal biopsies were obtained from 33 Australian AS patients (including 5 with concomitant IBD, 'AS-IBD'), 59 IBD patients and 105 healthy controls. Stool samples were also obtained from 16 Italian AS patients and 136 Swedish AS patients. Focusing on the Australian cohort, AS, AS-IBD and IBD patients differed from one another and from healthy controls in both alpha and beta diversity. AS patients with and without clinical IBD could be distinguished from one another with moderate accuracy using stool microbiome (AUC=0.754). Stool microbiome also accurately distinguished IBD patients from healthy controls (AUC=0.757). Microbiome composition was correlated with disease activity measured by BASDAI and faecal calprotectin (FCP) levels. Enrichment of potentially pathogenic Streptococcus was noted in AS, AS-IBD and IBD patients. Furthermore, enrichment of another potentially pathogenic genus, Haemophilus, was observed in AS, AS-IBD, IBD, AS patients with increased BASDAI, and IBD patients with faecal calprotectin >100 µg/mg. Apart from these genera, no other taxa were shared between AS and IBD patients. CONCLUSIONS: In conclusion, the distinct gut microbiome of AS and AS-IBD patients compared to IBD patients and healthy controls is consistent with immunological and genetic evidence suggesting that the gut plays a different role in driving AS compared with IBD. However, enrichment of two potentially pathogenic genera in both diseases suggests that the presence of a shared/common microbial trigger of disease cannot be discounted.

Depression, anxiety, fatigue, and quality of life in a large sample of patients suffering from head and neck cancer in comparison with the general population.

BACKGROUND: Treatment of head and neck cancer (HNC) often leads to visible and severe functional impairments. In addition, patients often suffer from a variety of psychosocial problems, significantly associated with a decreased quality of life. We aimed to compare depression, anxiety, fatigue and quality of life (QoL) between HNC patients and a large sample of the general population in Germany and to examine the impact of sociodemographic, behavioral and clinical factors on these symptoms. METHODS: We assessed data of HNC patients during the aftercare consultation at the Leipzig University Medical Center with a patient reported outcome (PRO) tool named "OncoFunction". Depression, anxiety, fatigue and QoL were assessed using validated outcome measures including the PHQ-9, the GAD-2, and the EORTC QLQ-C30 questionnaire. RESULTS: A total of 817 HNC patients were included in our study and compared to a sample of 5018 individuals of the general German population. HNC patients showed significantly higher levels of impairment in all dimensions assessed. Examination of association between depression, anxiety, fatigue and QoL and clinical as well as sociodemographic variables showed significant relationships between occupational status, ECOG-state, body mass index and time since diagnosis. CONCLUSIONS: HNC patients suffer significantly from psychological distress. The used questionnaires are suitable for the use in daily routine practice and can be helpful to increase the detection of depression, anxiety and fatigue and therefore can improve HNC aftercare.

How industrial bacterial cultures can be kept stable over time.

The tremendous variation that exists between bacterial species illustrates the power of evolution, which is the continuous process of mutation and selection over time. Even within a bacterial species, individual members can harbour an impressive degree of genetic variation, depending on the species. The question then arises how similar the offspring of a given bacterial cell over time is, and how long it takes before differences are noticeable? Here we show that on the one hand one can expect random mutations to arise, as a result of various mechanisms. On the other hand, there are forces at play that keep the offspring of a cell genetically relatively constant, unless there is selection for a particular characteristic. The most common mechanisms behind mutations that can appear in a bacterial population are briefly introduced. Next, it is explained why nevertheless such mutations are rarely observed, as long as single colonies are randomly selected, unless selective pressures apply. Since quality control of industrial bacterial cultures is likely to depend heavily on genome sequencing in the near future, the accuracy of whole-genomic sequencing technologies is also discussed. It can be concluded that the bacteriologists who started picking single colonies from agar plates more than hundred years ago were unknowingly ingeneous, as their practice maintains a bacterial culture stable over time. SIGNIFICANCE AND IMPACT OF STUDY: The questions addressed here are relevant for industries that depend on live bacteria for (manufacturing of) their products, as they have to guard their bacterial cultures that remain unchanged over time. The explanation why randomly selection of single colonies keeps a population stable can be of use in bacteriology courses. The limitations of whole-genome sequencing are relevant to legislators to avoid overinterpretation of those data.

A combination of LCPUFA ameliorates airway inflammation in asthmatic mice by promoting pro-resolving effects and reducing adverse effects of EPA.

Lipid mediators derived from omega (n)-3 and n-6 long-chain polyunsaturated fatty acids (LCPUFA) play key roles in bronchoconstriction, airway inflammation, and resolution processes in asthma. This study compared the effects of dietary supplementation with either a combination of LCPUFAs or eicosapentaenoic acid (EPA) alone to investigate whether the combination has superior beneficial effects on the outcome of asthmatic mice. Mice were sensitized with house dust mite (HDM) extract, and subsequently supplemented with either a combination of LCPUFAs or EPA alone in a recall asthma model. After the final HDM and LCPUFA administration, airway hyperresponsiveness (AHR), bronchoalveolar lavages, and lung histochemistry were examined. Lipid mediator profiles were determined by liquid chromatography coupled with tandem mass spectrometry (LC-MS-MS). The LCPUFA combination reduced AHR, eosinophilic inflammation, and inflammatory cytokines (IL-5, IFN-γ, and IL-6) in asthmatic mice, whereas EPA enhanced inflammation. The combination of LCPUFAs was more potent in downregulating EPA-derived LTB5 and LTC5 and in supporting DHA-derived RvD1 and RvD4 (2.22-fold and 2.58-fold higher levels) than EPA alone. Ex vivo experiments showed that LTB5 contributes to granulocytes' migration and M1-polarization in monocytes. Consequently, the LCPUFA combination ameliorated airway inflammation by inhibiting adverse effects of EPA and promoting pro-resolving effects supporting the lipid mediator-dependent resolution program.

A specific combined long-chain polyunsaturated fatty acid supplementation reverses fatty acid profile alterations in a mouse model of chronic asthma.

BACKGROUND: The immune-modulating potential of long-chain polyunsaturated fatty acids (LCPUFAs) based on their conversion into lipid mediators in inflammatory situations has been proven by several studies. Respecting the immune-modulative role of lipid mediators in bronchoconstriction, airway inflammation and resolution of inflammatory processes, LCPUFAs play an important role in asthma. To design a disease-specific and most beneficial LCPUFA supplementation strategy, it is essential to understand how asthma alters LCPUFA profiles. Therefore, this study characterizes the alterations of LCPUFA profiles induced by allergic asthma. In addition, this study explores whether a simple eicosapentaenoic acid (EPA) alone or a specific combined LCPUFA supplementation could restore imbalanced LCPUFA profiles. METHODS: Mice were sensitized with a daily dose of 40 µg house dust mite (HDM)-extract in a recall model and fed with either normal diet, EPA or a specific combined (sc)-LCPUFA supplementation containing EPA, docosahexaenoic acid (DHA), γ -linolenic acid (GLA) and stearidonic acid (SDA) for 24 days. After recall with HDM, mice were sacrificed and blood and lung tissue were collected. Fatty acid profiles were determined in plasma, blood cells and lung cells of asthmatic mice by capillary gas-chromatography. RESULTS: In lung cells of asthmatic mice, arachidonic acid (AA, p < 0.001) and DHA (p < 0.01) were increased while dihomo-γ-linolenic acid (DGLA, p < 0.05) was decreased. EPA supplementation increased only EPA (p < 0.001) and docosapentaenoic acid (DPA, p < 0.001), but neither DGLA nor DHA in lung cells of asthmatic mice. In contrast, a specific combined dietary supplementation containing n-3 and n-6 LCPUFAs could decrease AA (p < 0.001), increase EPA (p < 0.001), DPA (p < 0.001) and DHA (p < 0.01) and could reverse the lack of DGLA (p < 0.05). CONCLUSIONS: In summary, allergic asthma alters LCPUFA profiles in blood and lung tissue. In contrast to the EPA supplementation, the distinct combination of n-3 and n-6 LCPUFAs restored the LCPUFA profiles in lung tissue of asthmatic mice completely. Subsequently, sc-LCPUFA supplementation is likely to be highly supportive in limiting and resolving the inflammatory process in asthma.

Impact of antibiotic administration on blood culture positivity at the beginning of sepsis: a prospective clinical cohort study.

OBJECTIVES: Sepsis guidelines recommend obtaining blood cultures before starting anti-infective therapy in patients with sepsis. However, little is known of how antibiotic treatment before sampling affects bacterial growth. The aim of this study was to compare the results of blood cultures drawn before and during antibiotic therapy. METHODS: Prospective clinical cohort study of septic patients. Adult intensive care unit patients with two or three blood culture sets at the beginning of sepsis between 2010 and 2017 were included. Patients with blood culture samples obtained before antibiotic therapy were compared with patients with samples taken during antibiotic therapy. Blood culture positivity, defined as presence of a microbiological pathogen, was compared between the groups. Logistic regression was performed to adjust the impact of different factors with respect to blood culture positivity. RESULTS: In total, 559 patients with 1364 blood culture sets at the beginning of sepsis were analysed. Blood culture positivity was 50.6% (78/154) among patients with sepsis who did not receive antibiotics and only 27.7% (112/405) in those who were already receiving antibiotics (p <0.001). Logistic regression revealed antibiotic therapy as an independent factor for less pathogen identification (odds ratio 0.4; 95% CI 0.3-0.6). Gram-positive pathogens (28.3% (111/392) versus 11.9% (116/972); p <0.001) and also Gram-negative pathogens (16.3% (64/392) versus 9.3% (90/972); p <0.001) were more frequent in blood culture sets drawn before antibiotic therapy compared with sets obtained during antibiotic therapy. CONCLUSIONS: Obtaining blood cultures during antibiotic therapy is associated with a significant loss of pathogen detection. This strongly emphasizes the current recommendation to obtain blood cultures before antibiotic administration in patients with sepsis.

Fluorescent Labeling and 2-Photon Imaging of Mouse Tooth Pulp Nociceptors.

Retrograde fluorescent labeling of dental primary afferent neurons (DPANs) has been described in rats through crystalline fluorescent DiI, while in the mouse, this technique was achieved with only Fluoro-Gold, a neurotoxic fluorescent dye with membrane penetration characteristics superior to the carbocyanine dyes. We reevaluated this technique in the rat with the aim to transfer it to the mouse because comprehensive physiologic studies require access to the mouse as a model organism. Using conventional immunohistochemistry, we assessed in rats and mice the speed of axonal dye transport from the application site to the trigeminal ganglion, the numbers of stained DPANs, and the fluorescence intensity via 1) conventional crystalline DiI and 2) a novel DiI formulation with improved penetration properties and staining efficiency. A 3-dimensional reconstruction of an entire trigeminal ganglion with 2-photon laser scanning fluorescence microscopy permitted visualization of DPANs in all 3 divisions of the trigeminal nerve. We quantified DPANs in mice expressing the farnesylated enhanced green fluorescent protein (EGFPf) from the transient receptor potential cation channel subfamily M member 8 (TRPM8EGFPf/+) locus in the 3 branches. We also evaluated the viability of the labeled DPANs in dissociated trigeminal ganglion cultures using calcium microfluorometry, and we assessed the sensitivity to capsaicin, an agonist of the TRPV1 receptor. Reproducible DiI labeling of DPANs in the mouse is an important tool 1) to investigate the molecular and functional specialization of DPANs within the trigeminal nociceptive system and 2) to recognize exclusive molecular characteristics that differentiate nociception in the trigeminal system from that in the somatic system. A versatile tool to enhance our understanding of the molecular composition and characteristics of DPANs will be essential for the development of mechanism-based therapeutic approaches for dentine hypersensitivity and inflammatory tooth pain.

Activity and connectivity changes of central projection areas revealed by functional magnetic resonance imaging in NaV1.8-deficient mice upon cold signaling.

The voltage-gated sodium channel subtype NaV1.8 is expressed in the peripheral nervous system in primary afferent nociceptive C-fibers and is essential for noxious cold signaling. We utilized functional magnetic resonance imaging on NaV1.8-deficient (NaV1.8-/-) compared with wildtype (WT) mice to identify brain structures decoding noxious cold and/or heat signals. In NaV1.8-/- mice functional activity patterns, activated volumes and BOLD signal amplitudes are significantly reduced upon noxious cold stimulation whereas differences of noxious heat processing are less pronounced. Graph-theoretical analysis of the functional connectivity also shows dramatic alterations in noxious cold sensation in NaV1.8-/- mice and clearly reduced interactions between certain brain structures. In contrast, upon heat stimulation qualitatively quite the same functional connectivity pattern and consequently less prominent connectivity differences were observed between NaV1.8-/- and WT mice. Thus, the fact that NaV1.8-/- mice do not perceive nociceptive aspects of strong cooling in contrast to their WT littermates seems not only to be a pure peripheral phenomenon with diminished peripheral transmission, but also consists of upstream effects leading to altered subsequent nociceptive processing in the central nervous system and consequently altered connectivity between pain-relevant brain structures.

Pan-mutant-IDH1 inhibitor BAY1436032 is highly effective against human IDH1 mutant acute myeloid leukemia in vivo.

Neomorphic mutations in isocitrate dehydrogenase 1 (IDH1) are frequently found in several human cancer types including acute myeloid leukemia (AML) and lead to the production of high levels of the oncometabolite (R)-2-hydroxyglutarate (R-2HG). Here we report the characterization of BAY1436032, a novel pan-mutant IDH1 inhibitor, both in vitro and in vivo. BAY1436032 specifically inhibits R-2HG production and colony growth, and induces myeloid differentiation of AML cells carrying IDH1R132H, IDH1R132C, IDH1R132G, IDH1R132L and IDH1R132S mutations. In addition, the compound impacts on DNA methylation and attenuates histone hypermethylation. Oral administration of BAY1436032 led to leukemic blast clearance, myeloid differentiation, depletion of leukemic stem cells and prolonged survival in two independent patient-derived xenograft IDH1 mutant AML mouse models. Together, BAY1436032 is highly effective against all major types of IDH1 mutant AML.

Prevention of Allograft Rejection by Use of Regulatory T Cells With an MHC-Specific Chimeric Antigen Receptor.

CD4+ CD25high FOXP3+ regulatory T cells (Tregs) are involved in graft-specific tolerance after solid organ transplantation. However, adoptive transfer of polyspecific Tregs alone is insufficient to prevent graft rejection even in rodent models, indicating that graft-specific Tregs are required. We developed a highly specific chimeric antigen receptor that recognizes the HLA molecule A*02 (referred to as A2-CAR). Transduction into natural regulatory T cells (nTregs) changes the specificity of the nTregs without alteration of their regulatory phenotype and epigenetic stability. Activation of nTregs via the A2-CAR induced proliferation and enhanced the suppressor function of modified nTregs. Compared with nTregs, A2-CAR Tregs exhibited superior control of strong allospecific immune responses in vitro and in humanized mouse models. A2-CAR Tregs completely prevented rejection of allogeneic target cells and tissues in immune reconstituted humanized mice in the absence of any immunosuppression. Therefore, these modified cells have great potential for incorporation into clinical trials of Treg-supported weaning after allogeneic transplantation.

Crotalphine desensitizes TRPA1 ion channels to alleviate inflammatory hyperalgesia

Crotalphine is a structural analogue to a novel analgesic peptide that was first identified in the crude venom from the South American rattlesnake Crotalus durissus terrificus. Although crotalphine's analgesic effect is well established, its direct mechanism of action remains unresolved. The aim of the present study was to investigate the effect of crotalphine on ion channels in peripheral pain pathways. We found that picomolar concentrations of crotalphine selectively activate heterologously expressed and native TRPA1 ion channels. TRPA1 activation by crotalphine required intact N-terminal cysteine residues and was followed by strong and long-lasting desensitization of the channel. Homologous desensitization of recombinant TRPA1 and heterologous desensitization in cultured dorsal root ganglia neurons was observed. Likewise, crotalphine acted on peptidergic TRPA1-expressing nerve endings ex vivo as demonstrated by suppression of calcitonin gene-related peptide release from the trachea and in vivo by inhibition of chemically induced and inflammatory hypersensitivity in mice. The crotalphine-mediated desensitizing effect was abolished by the TRPA1 blocker HC030031 and absent in TRPA1-deficient mice. Taken together, these results suggest that crotalphine is the first peptide to mediate antinociception selectively and at subnanomolar concentrations by targeting TRPA1 ion channels

Voluntarily exposure to a single, high dose of probiotic Escherichia coli results in prolonged colonisation.

The ability of probiotic Escherichia coli to colonise the human gut was determined in a volunteer study following national (German) regulations. Five persons voluntarily took a single, high dose of Symbioflor®2, which contains 6 different probiotic E. coli genotypes, to assess tolerance of the product, after which presence of E. coli in their faeces was tested for a follow-up period of 30 weeks. Intake of the product did not result in severe side effect in any of the individuals, though mild side effects were observed. Stool analysis showed that the probiotic E. coli had colonised all five persons for a period of 10 to 30 weeks (mean: 18.7 weeks, median: 25.7 weeks). In two individuals there was evidence of competition between host E. coli and probiotic E. coli, while in two others total E. coli levels increased persistently with at least a factor of 10 as a result of the received dose. In one individual, who had lacked detectable levels of faecal E. coli at the start of the post-authorisation safety study, long-term colonisation was established, first by probiotic E. coli exclusively, which were later replaced by host E. coli strains. In four out of five individuals, total E. coli faecal counts were higher on average than at the start of the experiment, while in none total levels exceeded 5×107 cfu/g. When the specific genotypes of the 6 probiotic E. coli were analysed, it was found that one and the same common genotype was responsible for prolonged colonisation in all five individuals.

[Quality of life in primary and adjuvant veterinary radiation therapy. An owner survey]. / Lebensqualität der Patienten nach primärer und adjuvanter Strahlentherapie in der Kleintieronkologie. Eine Besitzerumfrage.

OBJECTIVE: External radiation therapy has been available since 2011 for small animals at the University of Munich. The aim of the study was to evaluate the quality of life of treated pets and the satisfaction of their owners. MATERIAL AND METHODS: The questionnaire was sent to the owners of all the pets (n = 91) that had undergone primary or adjuvant radiotherapy at the Clinic of Small Animal Medicine, University of Munich, since April 2011. RESULTS: The questionnaire was returned by 68 (74.7%) owners. According to their assessment, the quality of life improved in 41 cases (60.3%) after treatment where- as in 13 patients (19.1%) a decline was described. The majority of owners (88.2%) would have decided for repeated radiation therapy. CONCLUSION: Improvement of the animals' quality of life is related to a high satisfaction (83.8%) of the owners (p = 0.003) and their positive attitude towards radiotherapy (p = 0.027). CLINICAL RELEVANCE: Analyses showed that for these owners, the treatment was a worthwhile therapy despite it requiring much time and money.

Towards a consensus on a hearing preservation classification system.

CONCLUSION: The comprehensive Hearing Preservation classification system presented in this paper is suitable for use for all cochlear implant users with measurable pre-operative residual hearing. If adopted as a universal reporting standard, as it was designed to be, it should prove highly beneficial by enabling future studies to quickly and easily compare the results of previous studies and meta-analyze their data. OBJECTIVES: To develop a comprehensive Hearing Preservation classification system suitable for use for all cochlear implant users with measurable pre-operative residual hearing. METHODS: The HEARRING group discussed and reviewed a number of different propositions of a HP classification systems and reviewed critical appraisals to develop a qualitative system in accordance with the prerequisites. RESULTS: The Hearing Preservation Classification System proposed herein fulfills the following necessary criteria: 1) classification is independent from users' initial hearing, 2) it is appropriate for all cochlear implant users with measurable pre-operative residual hearing, 3) it covers the whole range of pure tone average from 0 to 120 dB; 4) it is easy to use and easy to understand.

Occurrence of livestock-associated methicillin-resistant Staphylococcus aureus in Turkey and broiler barns and contamination of air and soil surfaces in their vicinity.

The emission of microorganisms, especially resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA), from poultry farms is of public interest, and its occurrence and relevance are controversially discussed. So far, there are limited data on this issue. In this study, we investigated the occurrence of livestock-associated (LA)-MRSA inside and outside previously tested MRSA-positive poultry barns in Germany. In total, five turkey and two broiler fattening farms were investigated four and three times, respectively. In a longitudinal study during one fattening period, samples were collected from animals, the animals' environment inside the barn, including the air, and the barns' surroundings, such as ambient air and boot swabs of ground surfaces at different distances from the barn. Moreover, a cross-sectional study was carried out once inside the barns on five turkey and four broiler farms during the last third of the fatting period. In the cross-sectional study, LA-MRSA was detected in the air of most barns (7 of 9, 77.8%), as well as in many samples originating from animals, with detections levels of 50 to 54% in broiler and 62 to 77% in turkey farms. In the longitudinal study, LA-MRSA was found in the ambient air outside two turkey barns and on the ground surface on the downwind side of many (44.4%) turkey and broiler farms. The same spa types of isolates were observed inside and outside the barns. Transmission of MRSA within poultry farms, as well as emission via the airborne route, seems to be possible.

A vegan or vegetarian diet substantially alters the human colonic faecal microbiota.

BACKGROUND/OBJECTIVES: Consisting of ≈10(14) microbial cells, the intestinal microbiota represents the largest and the most complex microbial community inhabiting the human body. However, the influence of regular diets on the microbiota is widely unknown. SUBJECTS/METHODS: We examined faecal samples of vegetarians (n=144), vegans (n=105) and an equal number of control subjects consuming ordinary omnivorous diet who were matched for age and gender. We used classical bacteriological isolation, identification and enumeration of the main anaerobic and aerobic bacterial genera and computed absolute and relative numbers that were compared between groups. RESULTS: Total counts of Bacteroides spp., Bifidobacterium spp., Escherichia coli and Enterobacteriaceae spp. were significantly lower (P=0.001, P=0.002, P=0.006 and P=0.008, respectively) in vegan samples than in controls, whereas others (E. coli biovars, Klebsiella spp., Enterobacter spp., other Enterobacteriaceae, Enterococcus spp., Lactobacillus spp., Citrobacter spp. and Clostridium spp.) were not. Subjects on a vegetarian diet ranked between vegans and controls. The total microbial count did not differ between the groups. In addition, subjects on a vegan or vegetarian diet showed significantly (P=0.0001) lower stool pH than did controls, and stool pH and counts of E. coli and Enterobacteriaceae were significantly correlated across all subgroups. CONCLUSIONS: Maintaining a strict vegan or vegetarian diet results in a significant shift in the microbiota while total cell numbers remain unaltered.

The effects of maturation on the colonic microflora in infancy and childhood.

The composition of colonic mircoflora and its changes with maturation have rarely been investigated in large samples. Methods. We used conventional microbiological testing to analyse the colonic flora (Kyberstatus, Institut forMicroecology, Herborn, Germany) of stool samples from 12 484 children with different intestinal and nonintestinal diagnoses. Stool samples were analysed for total colony forming units (CFU) (per g stool) and the abundance of Bifidobacteria, Bacteroides sp., Escherichia coli, Enterococcus sp., and Lactobacillus sp. with respect to age, gender. A subset of 1089 infants was analysed for monthly changes within the first year of life. Results. Total CFU and individual microbial species were highest during the first year of life, decreased within the first 2 years, and then stabilized for the remaining childhood. In infants, the total CFU rose until month 5, declined with weaning, and peaked at 9-10 months. Significant effects of age, but not of gender, were found in Bacteroides sp. and Lactobacilli. However Bacterioids sp. and Lactobacilli increased with age, while Enterococci and E. coli decreased, and Bifidobacteria remained stable. Conclusion. Colonic microflora show both a bacteria-specific and general pattern of maturation which is most profound within the first year.