Early life factors and oral microbial signatures define the risk of caries in a Swedish cohort of preschool children

The oral cavity harbors complex communities comprising bacteria, archaea, fungi, protozoa, and viruses. The oral microbiota is establish at birth and develops further during childhood, with early life factors such as birth mode, feeding practices, and oral hygiene, reported to influence this development and the susceptibility to caries. We here analyzed the oral bacterial composition in saliva of 260 Swedish children at two, three and five years of age using 16S rRNA gene profiling to examine its relation to environmental factors and caries development at five years of age. We were able to assign the salivary bacterial community in each child at each time point to one of seven distinct clusters. We observed an individual dynamic in the development of the oral microbiota related to early life factors, such as being first born, born by C-section, maternal perinatal antibiotics use, with a distinct transition between three and five years of age. Different bacterial signatures depending on age were related to increased caries risk, while Peptococcus consistently linked to reduced risk of caries development.

Specific gut pathobionts escape antibody coating and are enriched during flares in patients with severe Crohn's disease

OBJECTIVE

Patients with Crohn's disease (CD) exhibit great heterogeneity in disease presentation and treatment responses, where distinct gut bacteria and immune interactions may play part in the yet unresolved disease aetiology. Given the role of antibodies in the barrier defence against microbes, we hypothesised that gut bacterial antibody-coating patterns may influence underlying disease-mediated processes.

DESIGN

Absolute and relative single and multicoating of gut bacteria with IgA, IgG1, IgG2, IgG3 and IgG4 in patients with CD and healthy controls were characterised and compared with disease activity. IgG2-coated and non-coated taxa from patients with severe CD were identified, profiled for pathogenic characteristics and monitored for enrichment during active disease across cohorts.

RESULTS

Patients with severe CD exhibited higher gut bacterial IgG2-coating. Supervised clustering identified 25 bacteria to be enriched in CD patients with high IgG2-coating. Sorting, sequencing and in silico-based assessments of the virulent potential of IgG2-coated and bulk stool bacteria were performed to evaluate the nature and pathogenicity of IgG2-coated and non-coated bacteria. The analyses demonstrated IgG2-coating of both known pathogenic and non-pathogenic bacteria that co-occurred with two non-coated pathobionts, Campylobacter and Mannheimia. The two non-coated pathobionts exhibited low prevalence, rarely coincided and were strongly enriched during disease flares in patients with CD across independent and geographically distant cohorts.

CONCLUSION

Distinct gut bacterial IgG2-coating was demonstrated in patients with severe CD and during disease flares. Co-occurrence of non-coated pathobionts with IgG2-coated bacteria points to an uncontrolled inflammatory condition in severe CD mediated via escape from antibody coating by two gut pathobionts.

Gut microbiota signatures in inflammatory bowel disease

BACKGROUND

Inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), affect millions of people worldwide with increasing incidence.

OBJECTIVES

Several studies have shown a link between gut microbiota composition and IBD, but results are often limited by small sample sizes. We aimed to re-analyze publicly available fecal microbiota data from IBD patients.

METHODS

We extracted original fecal 16S rRNA amplicon sequencing data from 45 cohorts of IBD patients and healthy individuals using the BioProject database at the National Center for Biotechnology Information. Unlike previous meta-analyses, we merged all study cohorts into a single dataset, including sex, age, geography, and disease information, based on which microbiota signatures were analyzed, while accounting for varying technical platforms.

RESULTS

Among 2518 individuals in the combined dataset, we discovered a hitherto unseen number of genera associated with IBD. A total of 77 genera associated with CD, of which 38 were novel associations, and a total of 64 genera associated with UC, of which 28 represented novel associations. Signatures were robust across different technical platforms and geographic locations. Reduced alpha diversity in IBD compared to healthy individuals, in CD compared to UC, and altered microbiota composition (beta diversity) in UC and especially in CD as compared to healthy individuals were found.

CONCLUSIONS

Combining original microbiota data from 45 cohorts, we identified a hitherto unseen large number of genera associated with IBD. Identification of microbiota features robustly associated with CD and UC may pave the way for the identification of new treatment targets.

IgG and IgM cooperate in coating of intestinal bacteria in IgA deficiency

Immunoglobulin A (IgA) is acknowledged to play a role in the defence of the mucosal barrier by coating microorganisms. Surprisingly, IgA-deficient humans exhibit few infection-related complications, raising the question if the more specific IgG may help IgM in compensating for the lack of IgA. Here we employ a cohort of IgA-deficient humans, each paired with IgA-sufficient household members, to investigate multi-Ig bacterial coating. In IgA-deficient humans, IgM alone, and together with IgG, recapitulate coating of most bacterial families, despite an overall 3.6-fold lower Ig-coating. Bacterial IgG coating is dominated by IgG1 and IgG4. Single-IgG2 bacterial coating is sparse and linked to enhanced Escherichia coli load and TNF-α. Although single-IgG2 coating is 1.6-fold more prevalent in IgA deficiency than in healthy controls, it is 2-fold less prevalent than in inflammatory bowel disease. Altogether we demonstrate that IgG assists IgM in coating of most bacterial families in the absence of IgA and identify single-IgG2 bacterial coating as an inflammatory marker.

Association between lipid-A-producing oral bacteria of different potency and fractional exhaled nitric oxide in a Norwegian population-based adult cohort

BACKGROUND

Lipid A is the primary immunostimulatory part of the lipopolysaccharide (LPS) molecule. The inflammatory response of LPS varies and depends upon the number of acyl chains and phosphate groups in lipid A which is specific for a bacterial species or strain. Traditional LPS quantification assays cannot distinguish between the acylation degree of lipid A molecules, and therefore little is known about how bacteria with different inflammation-inducing potencies affect fractional exhaled nitric oxide (F_eNO). We aimed to explore the association between pro-inflammatory hexa- and less inflammatory penta-acylated LPS-producing oral bacteria and F_eNO as a marker of airway inflammation.

METHODS

We used data from a population-based adult cohort from Norway (n = 477), a study center of the RHINESSA multi-center generation study. We applied statistical methods on the bacterial community- (prediction with MiRKAT) and genus-level (differential abundance analysis with ANCOM-BC) to investigate the association between the oral microbiota composition and F_eNO.

RESULTS

We found the overall composition to be significantly associated with increasing F_eNO levels independent of covariate adjustment, and abundances of 27 bacterial genera to differ in individuals with high F_eNO vs. low F_eNO levels. Hexa- and penta-acylated LPS producers made up 2.4% and 40.8% of the oral bacterial genera, respectively. The Bray-Curtis dissimilarity within hexa- and penta-acylated LPS-producing oral bacteria was associated with increasing F_eNO levels independent of covariate adjustment. A few single penta-acylated LPS producers were more abundant in individuals with low F_eNO vs. high F_eNO, while hexa-acylated LPS producers were found not to be enriched.

CONCLUSIONS

In a population-based adult cohort, F_eNO was observed to be associated with the overall oral bacterial community composition. The effect of hexa- and penta-acylated LPS-producing oral bacteria was overall significant when focusing on Bray-Curtis dissimilarity within each of the two communities and F_eNO levels, but only penta-acylated LPS producers appeared to be reduced or absent in individuals with high F_eNO. It is likely that the pro-inflammatory effect of hexa-acylated LPS producers is counteracted by the dominance of the more abundant penta-acylated LPS producers in this population-based adult cohort involving mainly healthy individuals.

Gut Microbiota Perturbation in IgA Deficiency Is Influenced by IgA-Autoantibody Status

BACKGROUND & AIMS

IgA exerts its primary function at mucosal surfaces, where it binds microbial antigens to regulate bacterial growth and epithelial attachment. One third of individuals with IgA deficiency (IgAD) suffers from recurrent mucosal infections, possibly related to an altered microbiota. We aimed to delineate the impact of IgAD and the IgA-autoantibody status on the composition and functional capacity of the gut microbiota.

METHODS

We performed a paired, lifestyle-balanced analysis of the effect of IgA on the gut microbiota composition and functionality based on fecal samples from individuals with IgAD and IgA-sufficient household members (n = 100), involving quantitative shotgun metagenomics, species-centric functional annotation of gut bacteria, and strain-level analyses. We supplemented the data set with 32 individuals with IgAD and examined the influence of IgA-autoantibody status on the composition and functionality of the gut microbiota.

RESULTS

The gut microbiota of individuals with IgAD exhibited decreased richness and diversity and was enriched for bacterial species encoding pathogen-related functions including multidrug and antimicrobial peptide resistance, virulence factors, and type III and VI secretion systems. These functional changes were largely attributed to Escherichia coli but were independent of E coli strain variations and most prominent in individuals with IgAD with IgA-specific autoreactive antibodies.

CONCLUSIONS

The microbiota of individuals with IgAD is enriched for species holding increased proinflammatory potential, thereby potentially decreasing the resistance to gut barrier-perturbing events. This phenotype is especially pronounced in individuals with IgAD with IgA-specific autoreactive antibodies, thus warranting a screening for IgA-specific autoreactive antibodies in IgAD to identify patients with IgAD with increased risk for gastrointestinal implications.

The intestinal microbiome is a co-determinant of the postprandial plasma glucose response

Elevated postprandial plasma glucose is a risk factor for development of type 2 diabetes and cardiovascular disease. We hypothesized that the inter-individual postprandial plasma glucose response varies partly depending on the intestinal microbiome composition and function. We analyzed data from Danish adults (n = 106), who were self-reported healthy and attended the baseline visit of two previously reported randomized controlled cross-over trials within the Gut, Grain and Greens project. Plasma glucose concentrations at five time points were measured before and during three hours after a standardized breakfast. Based on these data, we devised machine learning algorithms integrating bio-clinical, as well as shotgun-sequencing-derived taxa and functional potentials of the intestinal microbiome to predict individual postprandial glucose excursions. In this post hoc study, we found microbial and clinical features, which predicted up to 48% of the inter-individual variance of postprandial plasma glucose responses (Pearson correlation coefficient of measured vs. predicted values, R = 0.69, 95% CI: 0.45 to 0.84, p<0.001). The features were age, fasting serum triglycerides, systolic blood pressure, BMI, fasting total serum cholesterol, abundance of Bifidobacterium genus, richness of metagenomics species and abundance of a metagenomic species annotated to Clostridiales at order level. A model based only on microbial features predicted up to 14% of the variance in postprandial plasma glucose excursions (R = 0.37, 95% CI: 0.02 to 0.64, p = 0.04). Adding fasting glycaemic measures to the model including microbial and bio-clinical features increased the predictive power to R = 0.78 (95% CI: 0.59 to 0.89, p<0.001), explaining more than 60% of the inter-individual variance of postprandial plasma glucose concentrations. The outcome of the study points to a potential role of the taxa and functional potentials of the intestinal microbiome. If validated in larger studies our findings may be included in future algorithms attempting to develop personalized nutrition, especially for prediction of individual blood glucose excursions in dys-glycaemic individuals.

Division of Labor during Biofilm Matrix Production

Organisms as simple as bacteria can engage in complex collective actions, such as group motility and fruiting body formation. Some of these actions involve a division of labor, where phenotypically specialized clonal subpopulations or genetically distinct lineages cooperate with each other by performing complementary tasks. Here, we combine experimental and computational approaches to investigate potential benefits arising from division of labor during biofilm matrix production. We show that both phenotypic and genetic strategies for a division of labor can promote collective biofilm formation in the soil bacterium Bacillus subtilis. In this species, biofilm matrix consists of two major components, exopolysaccharides (EPSs) and TasA. We observed that clonal groups of B. subtilis phenotypically segregate into three subpopulations composed of matrix non-producers, EPS producers, and generalists, which produce both EPSs and TasA. This incomplete phenotypic specialization was outperformed by a genetic division of labor, where two mutants, engineered as specialists, complemented each other by exchanging EPSs and TasA. The relative fitness of the two mutants displayed a negative frequency dependence both in vitro and on plant roots, with strain frequency reaching a stable equilibrium at 30% TasA producers, corresponding exactly to the population composition where group productivity is maximized. Using individual-based modeling, we show that asymmetries in strain ratio can arise due to differences in the relative benefits that matrix compounds generate for the collective and that genetic division of labor can be favored when it breaks metabolic constraints associated with the simultaneous production of two matrix components.

Systemic stiffening of mouse tail tendon is related to dietary advanced glycation end products but not high-fat diet or cholesterol

Tendon pathology is related to metabolic disease and mechanical overloading, but the effect of metabolic disease on tendon mechanics is unknown. This study investigated the effect of diet and apolipoprotein E deficiency (ApoE(-/-)) on mechanical properties and advanced glycation end product (AGE) cross-linking of non-weight-bearing mouse tail tendons. Twenty ApoE(-/-) male mice were used as a model for hypercholesterolemia along with 26 wild-type (WT) mice. One-half of the mice from each group was fed a normal diet (ND) and the other half was fed a high-fat diet (HFD) to induce obesity. All were killed at 40 wk, and tail tendon fascicles were mechanically tested to failure and analyzed for AGEs. Diets were also analyzed for AGEs. ApoE(-/-) mice displayed a 14% increase in plateau modulus compared with WT mice (P < 0.05), whereas HFD mice displayed a 13% decrease in plateau modulus (P < 0.05) and a 12% decrease in total modulus (P < 0.05) compared with ND mice. Tail tendons of HFD mice had significantly lower concentrations of AGEs [carboxymethyllysine (CML): 26%, P < 0.0001; methylglyoxal-derived hydroimidazolone 1 (MG-H1): 15%, P < 0.005; pentosidine: 13%, P < 0.0005]. The HFD had ∼44-fold lower content of CML (P < 0.01), ∼29-fold lower content of carboxyethyllysine (P < 0.005), and ∼16-fold lower content of MG-H1 (P < 0.05) compared with ND. ApoE(-/-) increased, whereas HFD decreased mouse tail tendon stiffness. Dietary AGE content may be a crucial determinant for accumulation of AGE cross-links in tendons and for tissue compliance. The results demonstrate how systemic metabolic factors may influence tendon health.

Videothoracoscopic lung biopsy by a stapling technique

OBJECTIVES

To describe initial experience with a new technique for obtaining lung biopsy specimens using video-thoracoscopy and Multifire Endo GIA (U.S. Surgical Corporation) stapler.

DESIGN

Retrospective study.

SETTING

Central hospital, Denmark.

SUBJECTS

Nine patients with suspected pulmonary fibrosis.

MAIN OUTCOME MEASURES

Diagnosis, morbidity, and mortality.

RESULTS

The endoscopic method provided a specimen of lung tissue large enough to secure a reliable diagnosis in all cases.

CONCLUSION

The thoracoscopic technique implies less surgical trauma than thoracotomy resulting in less postoperative pain and a better cosmetic result. In patients suitable for general anaesthesia the endoscopic method for obtaining lung tissue specimen seems to be the ideal method.

Recovery from repeated sudden hearing loss with corticosteroid use in the presence of an acoustic neuroma

Sensorineural hearing loss of sudden onset may be the presenting symptom in up to 14% of patients with acoustic neuroma. We present the first reported case of sudden hearing loss in an only hearing ear with recovery to normal levels after steroid therapy on four separate occasions. Evaluation revealed a 1.5-cm acoustic neuroma. After middle cranial fossa decompression, a fifth episode with recovery after steroid use was documented. A review of the recent literature is presented, emphasizing the possible causation of sudden sensorineural hearing loss with recovery to normal in patients with acoustic neuroma. Modalities of therapy for the dilemma of the acoustic neuroma in an only hearing ear are discussed, including surgery, radiotherapy, and chemotherapy. An aggressive approach to the evaluation of the cause of sudden hearing loss is suggested.

Vagal paragangliomas: a report of nine cases

Vagal paragangliomas are rare tumors of neural crest origin: fewer than 175 cases have been reported in the English literature. This slow-growing tumor occurs most often at the base of the skull in the parapharyngeal space, but may arise anywhere along the course of the vagus nerve and its branches. Nine clinical presentations and the surgical outcome in seven patients with vagal paragangliomas treated at our institution are reported. A review of the literature, emphasizing evaluation and treatment of these potentially fatal neoplasms, is discussed. Surgical removal is the treatment of choice with vagal tumors. Complications related to the ablation or injury of cranial nerves IX, X, XI, and XII are commonly seen. Surgical techniques that may prevent injury to these vital neural structures are outlined. The postoperative treatment of patients with impaired deglutition secondary to multiple cranial neuropathies is discussed.

Diagnosis and management of cleft larynx. Literature review and case report

Laryngeal cleft is a rare congenital laryngeal anomaly that has been recognized more frequently in recent years. It can be a serious problem, consisting of separation of the arytenoids with a fissure resulting from a defect in the fusion of the posterior cricoid cartilage lamina. Dysphagia with aspiration of food is commonly seen with resultant bouts of pneumonia. Surgical repair has been successful in a handful of cases. This communication will review our institution's recent handling of a case successfully treated. The epidemiology, embryology, classification, diagnosis, and suggested treatment regimen for laryngeal cleft will also be outlined.

Pharmacological manipulation of adynamic ileus: controlled randomized double-blind study of ceruletide on intestinal motor activity after elective abdominal surgery

In a double-blind placebo-controlled trial of patients undergoing elective abdominal surgery (n = 91), a single intravenous infusion of ceruletide (2.5 ng kg-1 min-1 for 1 hour) resulted in audible bowel sounds in 42/47 patients as opposed to 30/44 receiving placebo (P less than 0.025). Excessive bowel sounds were noted in 16 patients in the ceruletide group and four receiving placebo (P less than 0.01). Significantly more patients (P less than 0.01) in the ceruletide group (22/45 versus 9/44) passed flatus per rectum between the second and third post-operative day. Ceruletide infusion was accompanied by a significant increase in the incidence of nausea and vomiting (P less than 0.005, P less than 0.0025) but these side effects were short-lived. These results indicate that ceruletide is likely to be a useful therapeutic agent for acute intestinal adynamic motility disorders.

Perivascular axillary block VII: the effect of a supplementary dose of 20 ml mepivacaine 1% with adrenaline to patients with incomplete sensory blockade

Perivascular axillary blockade was performed on 233 patients with the aid of a catheter technique. All patients received a primary injection of 50 ml of mepivacaine 1% with adrenaline. Sensory blockade was evaluated 20, 30 and 40 min after injection, and a complete sensory blockade was found in 90 (39%), 131 (57%) and 146 (63%), respectively. The blockade effect of a supplementary perivascular injection of 20 ml of the same agent was investigated on the remaining 87 blockades, which could be divided into three categories: blockades which at 20 min showed lack of analgesia in several cutaneous segments of the hand (34 patients); blockades which at 30 min showed a total lack of sensory blockade within a limited area (29 patients); and blockades which at 40 min showed signs of blockade of all cutaneous segments, but one or several segments were not blocked with an intensity compatible with surgery (24 patients). Blockades of categories 1 and 2 were at 20 and 30 min, respectively, randomly allocated to control or to perivascular supplementation groups, while blockades of category 3 all had supplementation at 40 min. Sensory blockade was reevaluated 10 and 20 min after group allocation, and it was found that perivascular supplementation had no significant effect on the sensory blockade in category 1 and 2, while 68% of the blockades in category 3 improved to a complete blockade.(ABSTRACT TRUNCATED AT 250 WORDS)

Perivascular axillary block III: blockade following 40 ml of 0.5%, 1% or 1.5% mepivacaine with adrenaline

Perivascular axillary blockade was performed on 90 patients with the aid of a catheter technique. All blockades were performed by the same anaesthetist, who practised perivascular axillary blockade three or four times a day. The patients were randomly allocated to three groups. The injected volume of local anaesthetic was constant in each group: 40 ml mepivacaine with adrenaline. The concentration and, consequently, the amount (mg) were variable factors: 1/2% (200 mg), 1% (400 mg) and 1 1/2% (600 mg). Sensory and motor blockade were tested 30 min after each injection. All three groups showed a high incidence of analgesia (70%-100%) in all cutaneous segments, and none of the blockades showed total failure of the sensory blockade. The lowest incidence of sensory blockade was found in the areas innervated by the axillary, the radial and the musculocutaneous nerves, but no difference was found between the groups. However, the motor blockade was found to improve with increasing concentration of local anaesthetic solution.

Haemodynamic effects of calcium chloride administered intravenously to patients with and without cardiac disease during neurolept anaesthesia

During neurolept anaesthesia, calcium chloride (15 mg/kg) was administered intravenously to two different groups of patients undergoing vascular surgery on the abdominal aorta. The patients in group I all suffered from cardiac disease and were treated with digoxin, while the patients in group II had no cardiac symptoms. Cardiovascular measurements were made during steady-state anaesthesia. In group I, CaCl2 increased cardiac index (CI) significantly while systemic vascular resistance index (SVRI) remained unchanged. Mean arterial pressure (MAP) increased. In group II, both MAP and SVRI increased while CI remained unchanged. No significant changes in heart rate were observed and no arrhythmias occurred. It is concluded that CaCl2 administered intravenously is an effective means of improving cardiac function when it is depressed by anaesthesia, underlying cardiac disease, or both.

Perivascular axillary block. I: blockade following 40 ml 1% mepivacaine with adrenaline

Perivascular axillary block was performed on 80 patients by a catheter technique. All patients had a standard dose of 40 ml mepivacaine 1% with adrenaline. Thirty minutes after the injection, the motor and sensory blockade was determined. Eighty-six per cent of the patients had a distinct motor blockade, whereas the remaining 14% had only a slight motor blockade. The sensory blockade was complete in 63%, whereas 37% had lack of analgesia in one or several cutaneous areas. Lack of analgesia was most often found in the cutaneous area of the axillary, musculocutaneous and radial nerves. The frequency of analgesia in the three areas of innervation was analysed with reference to the influence of the age, height and weight of the patient, and of differences in technique: paraesthesias, position of catheter, and unintended puncture of blood vessels. None of these variables seems to be important for the low frequency of analgesia in the three areas of innervation.