Functional diversity within the simple gut microbiota of the honey bee

Animals living in social communities typically harbor a characteristic gut microbiota important for nutrition and pathogen defense. Accordingly, in the gut of the honey bee, Apis mellifera, a distinctive microbial community, composed of a taxonomically restricted set of species specific to social bees, has been identified. Despite the ecological and economical importance of honey bees and the increasing concern about population declines, the role of their gut symbionts for colony health and nutrition is unknown. Here, we sequenced the metagenome of the gut microbiota of honey bees. Unexpectedly, we found a remarkable degree of genetic diversity within the few bacterial species colonizing the bee gut. Comparative analysis of gene contents suggests that different species harbor distinct functional capabilities linked to host interaction, biofilm formation, and carbohydrate breakdown. Whereas the former two functions could be critical for pathogen defense and immunity, the latter one might assist nutrient utilization. In a γ-proteobacterial species, we identified genes encoding pectin-degrading enzymes likely involved in the breakdown of pollen walls. Experimental investigation showed that this activity is restricted to a subset of strains of this species providing evidence for niche specialization. Long-standing association of these gut symbionts with their hosts, favored by the eusocial lifestyle of honey bees, might have promoted the genetic and functional diversification of these bee-specific bacteria. Besides revealing insights into mutualistic functions governed by the microbiota of this important pollinator, our findings indicate that the honey bee can serve as a model for understanding more complex gut-associated microbial communities.     

Bacterial expression of mutant argininosuccinate lyase reveals imperfect correlation of in-vitro enzyme activity with clinical phenotype in argininosuccinic aciduria

Background

The urea cycle defect argininosuccinate lyase (ASL) deficiency has a large spectrum of presentations from highly severe to asymptomatic. Enzyme activity assays in red blood cells or fibroblasts, although diagnostic of the deficiency, fail to discriminate between severe, mild or asymptomatic cases. Mutation/phenotype correlation studies are needed to characterize the effects of individual mutations on the activity of the enzyme.

Methods

Bacterial in-vitro expression studies allowed the enzyme analysis of purified mutant ASL proteins p.I100T (c.299?T?>?C), p.V178M (c.532?G?>?A), p.E189G (c.566A?>?G), p.Q286R (c.857A?>?G), p.K315E (c.943A?>?G), p.R379C (c.1135?C?>?T) and p.R385C (c.1153?C?>?T) in comparison to the wildtype protein.

Results

In the bacterial in-vitro expression system, ASL wild-type protein was successfully expressed. The known classical p.Q286R, the novel classical p.K315E and the known mutations p.I100T, p.E189G and p.R385C, which all have been linked to a mild phenotype, showed no significant residual activity. There was some enzyme activity detected with the p.V178M (5 % of wild-type) and p.R379C (10 % of wild-type) mutations in which K_m values for argininosuccinic acid differed significantly from the wild-type ASL protein.

Conclusion

The bacterially expressed enzymes proved that the mutations found in patients and studied here indeed are detrimental. However, as in the case of red cell ASL activity assays, some mutations found in genetically homozygous patients with mild presentations resulted in virtual loss of enzyme activity in the bacterial system, suggesting a more protective environment for the mutant enzyme in the liver than in the heterologous expression system and/or in the highly dilute assays utilized here.     

Neuroendocrine assessment of serotonergic, dopaminergic, and noradrenergic functions in alcohol-dependent individuals

Background: Alcohol dependence has been associated with reduced function of serotonin, dopamine as well as noradrenaline activities in several neuroendocrine studies. To our knowledge, there is, however, no study investigating all these 3 systems with the use of neuroendocrine methods in one and the same alcohol‐dependent individual. Methods: Alcohol‐dependent individuals (n = 42) and controls (n = 28) participated in the neuroendocrine test series. Central serotonergic neurotransmission was assessed by the prolactin (PRL) response to citalopram (CIT). The postsynaptic DRD2 function was measured by the growth hormone (GH) response to apomorphine (APO) and the postsynaptic α2‐adrenoceptor function by GH response to clonidine (CLON). Results: In the alcohol‐dependent individuals, the PRL concentrations were significantly lower at the time points 240 minutes and 300 minutes after CIT administration and mean delta PRL value was significantly reduced by 45% in comparison with controls. There were no significant differences in APO‐GH and CLON‐GH concentrations at any time points or in mean delta GH values between the groups. An impaired monoaminergic profile, including all 3 systems, was significantly more frequent in alcohol‐dependent individuals than controls (43% vs. 6% respectively). Conclusions: The monoaminergic dysfunction was restricted to an impairment of the serotonergic system, suggesting that this system is especially vulnerable to long‐term and excessive alcohol consumption. Moreover, impaired monoaminergic profiles, including low responses in 2 or 3 systems, were more frequently observed in alcohol‐dependent individuals than in controls. Such impaired profiles may be of clinical importance, but further studies are needed.     

Atrial arrhythmia burden on long-term monitoring in asymptomatic patients late after atrial fibrillation ablation

Patients appearing free of atrial fibrillation (AF) based on limited electrocardiographic monitoring/clinical history late after ablation may still have a large silent AF burden and thus have failed ablations and may be at risk of thromboembolism. We evaluated long-term monitoring (LTM; 7 days or 1 year) in 203 patients off antiarrhythmic drugs who were clinically free of AF >1 year after ablation. A 7-day monitor was done in 186 and 17 had pacemakers in whom the most recent year was analyzed. Arrhythmia recurrence was >30 seconds of AF, flutter, or tachycardia. LTM was done 3.1 ± 1.3 years (range 1.1 to 7.3) after the last ablation. AF recurred in only 8 of 186 (4.3%) on 7-day monitoring. One had persistent AF. For the other 7, AF burden was 0.0075% to 3.34% with 3 of 7 having an AF burden ≤0.037%. AF recurred in 4 of 17 patients (23.5%) with pacemakers. The 4 patients with pacemakers and AF had a 1-year AF burden of 0.0037% to 0.16%. Given the longer duration of monitoring, pacemakers detected more AF than 7-day monitors (p <0.011). AF duration before ablation was the only predictor of AF recurrence on LTM (p = 0.01). In patients with symptomatic AF who appeared free of AF on clinical grounds an average of 3 years after ablation, AF burden on LTM was low. In conclusion, monitoring by implanted devices detects more AF than 7-day monitors, most patients exceeding the failure definition of >30 seconds have a small AF burden, and when using LTM for follow-up the definition of "ablation failure" may be better described by an AF burden >0.5% rather than a single 30-second arrhythmia recurrence.     

Subtotal cranial vault remodelling in anterior sagittal suture closure: impact of age on surgical outcome

Isolated fusion of the sagittal suture is usually treated before 1 year of age, but some patients present at a later age. The aim of this study was to evaluate the impact of children's age on the surgical outcome. The authors investigated 46 patients with isolated nonsyndromic sagittal craniosynostosis limited to the anterior two-thirds of the cranial vault. All patients underwent subtotal cranial vault remodelling, 36 patients (78.3%) before the age of 12 months (mean 8.92 months) and 10 patients after the age of 12 months (mean 15.77 months). Perioperative parameters and measurements of the cephalic index, preoperatively and postoperatively, were evaluated. All 46 patients showed improved head shape independent of their age. In patients younger than 12 months, mean cephalic indices improved from 65.99 to 74.49 (p<0.0001) and in patients older than 12 months from 66.38 to 74.38 (p<0.0004). There were no statistical differences in perioperative parameters including length of surgery, intraoperative blood loss and duration of hospital stay. In this study, patients showed no significant differences in surgical outcome that could have been related to the age at surgery. Surgical treatment should be performed early enough to benefit from the remodelling potential of the skull.     

Ki-67 expression predicts radiosensitivity in oral squamous cell carcinoma

The prognostic relevance of Ki-67 expression in oral squamous cell carcinoma (OSCC) is still controversial. As proliferating cells are more susceptible to ionizing radiation, the authors investigated if a high proliferation rate reflected by Ki-67 expression, predicts radiosensitivity in OSCC patients. In 52 patients with OSCC who received primary surgery followed by radiation therapy, the proliferation rate was assessed by Ki-67 immunhistochemistry and correlated to recurrent free survival and overall survival. Low proliferative carcinomas showed a significantly shorter mean time to recurrence of 27.5 months compared to 49.5 months of high proliferative tumours (p=0.048). The 5-year survival rate of low proliferative tumours was 49% compared to 80% for high proliferative tumours (p=0.042). This study indicates that tumours with high proliferative activity are more susceptible to radiation therapy. Ki-67 might be used as a marker to predict the response to radiation therapy in patients with OSCC.     

Surgical outcome after using a modified technique of the pi-procedure for posterior sagittal suture closure

Fusion of the sagittal suture is the most prevalent form of craniosynostosis. Due to the variety of deformities of scaphocephaly depending on the location of the fused sagittal suture, the surgical procedure has to be adjusted to the individual case.In this study, 38 patients with a predominantly posterior sagittal suture closure were treated with a modified technique of the pi-procedure and the surgical outcome has been evaluated with respect to complications, morphological and aesthetic outcome.The improvement of the cephalic index in our series in the follow-up examination (mean 60.1 months) after surgery was significant (p < 0.0001). According to the classification of Whitaker, 31 patients had a Class 1 outcome, with excellent surgical results. Aesthetic outcomes were excellent in 29, good in 5, and poor in 4 of cases, as judged by both the families and the craniofacial team. No severe complications have been observed.Posterior sagittal suture with marked occipital bulging can be successfully treated with this modified posterior procedure with a low complication rate, significant improvement of the cephalic index and a good aesthetic outcome. In all cases of sagittal synostosis, the operative procedure should be tailored to the nature and severity of the deformity.     

Reconstruction of a near-total nasal defect using a precontoured titanium mesh with a converse scalping flap

ABSTRACT: The reconstruction in case of large nasal defects, especially affecting the cartilaginous portion, is a surgical and aesthetic challenge. The result has to fulfill functional and aesthetic aspects concerning shape, texture, and nasal breathing, which requires accurate reproduction of nasal lining, support, and coverage. Here, we describe nasal reconstruction in a 36-year-old woman after near-total nasal resection due to a malignant peripheral nerve sheath tumor in the glabellar and nasal regions. After tumor resection, the cartilaginous and bone structures were reconstructed using a dynamic titanium mesh, which was precontoured on a three-dimensional-print model of the preoperative situation. Soft tissue defects were covered as a 2-stage procedure using a Converse scalp flap. We achieved an adequate long-term functional and aesthetic and oncological result. Titanium mesh in combination with Converse flap proved to be an alternative in extensive composite midfacial defects.     

Shear bond strength and enamel fracture behavior of ceramic brackets Fascination? and Fascination?2

Objective

The purpose of this study was to compare the shear bond strength and incidence of enamel fractures of the ceramic brackets Fascination? and Fascination?2.

Materials and methods

A total of 360 teeth (180 first upper bicuspids and 180 lower incisors) were stored in 96% ethanol, while 360 other teeth (180 first upper bicuspids and 180 lower incisors) were stored in 0.1% thymol. All 720 teeth were bonded one-half each with Fascination? and Fascination?2 brackets using three different adhesives and three different light curing units. The teeth were debonded with a debonding-device according to DIN EN ISO 10477 using a universal testing machine with a crosshead speed of 1?mm per minute. The enamel surface was then examined stereomicroscopically (10x and 40x magnification). The non-parametric Mann?CWhitney U test was used, since the data were not normally distributed.

Results

The Fascination?2 brackets provided significantly lower shear bond strength than Fascination? brackets (p?=?0.003). Fascination? brackets demonstrated significantly fewer, smaller enamel fractures than Fascination?2 brackets (p?=?0.012).

Conclusion

The lower shear bond strength of the Fascination?2 brackets is clinically acceptable, but our study??s experimental design did not enable us to prove whether this is clinically associated with a lower risk of enamel fracture.