Specialized digestive mechanism for an insect-bacterium gut symbiosis.

In Burkholderia-Riptortus symbiosis, the host bean bug Riptortus pedestris harbors Burkholderia symbionts in its symbiotic organ, M4 midgut, for use as a nutrient source. After occupying M4, excess Burkholderia symbionts are moved to the M4B region, wherein they are effectively digested and absorbed. Previous studies have shown that M4B has strong symbiont-specific antibacterial activity, which is not because of the expression of antimicrobial peptides but rather because of the expression of digestive enzymes, mainly cathepsin L protease. However, in this study, inhibition of cathepsin L activity did not reduce the bactericidal activity of M4B, indicating that there is an unknown digestive mechanism that renders specifically potent bactericidal activity against Burkholderia symbionts. Transmission electron microscopy revealed that the lumen of symbiotic M4B was filled with a fibrillar matter in contrast to the empty lumen of aposymbiotic M4B. Using chromatographic and electrophoretic analyses, we found that the bactericidal substances in M4B existed as high-molecular-weight (HMW) complexes that were resistant to protease degradation. The bactericidal HMW complexes were visualized on non-denaturing gels using protein- and polysaccharide-staining reagents, thereby indicating that the HMW complexes are composed of proteins and polysaccharides. Strongly stained M4B lumen with Periodic acid-Schiff (PAS) reagent in M4B paraffin sections confirmed HMW complexes with polysaccharide components. Furthermore, M4B smears stained with Periodic acid-Schiff revealed the presence of polysaccharide fibers. Therefore, we propose a key digestive mechanism of M4B: bacteriolytic fibers, polysaccharide fibers associated with digestive enzymes such as cathepsin L, specialized for Burkholderia symbionts in Riptortus gut symbiosis.

Brain-wide mapping reveals that engrams for a single memory are distributed across multiple brain regions.

Neuronal ensembles that hold specific memory (memory engrams) have been identified in the hippocampus, amygdala, or cortex. However, it has been hypothesized that engrams of a specific memory are distributed among multiple brain regions that are functionally connected, referred to as a unified engram complex. Here, we report a partial map of the engram complex for contextual fear conditioning memory by characterizing encoding activated neuronal ensembles in 247 regions using tissue phenotyping in mice. The mapping was aided by an engram index, which identified 117 cFos+ brain regions holding engrams with high probability, and brain-wide reactivation of these neuronal ensembles by recall. Optogenetic manipulation experiments revealed engram ensembles, many of which were functionally connected to hippocampal or amygdala engrams. Simultaneous chemogenetic reactivation of multiple engram ensembles conferred a greater level of memory recall than reactivation of a single engram ensemble, reflecting the natural memory recall process. Overall, our study supports the unified engram complex hypothesis for memory storage.

Treatment of atypical pacemaker-mediated tachycardia with ablation of the retrograde atrioventricular nodal pathway.

A 25-year-old runner received a single-lead, VDD pacemaker after ablation of AV nodal reentrant tachycardia complicated by intermittent AV block. The rate-adaptive AV delay algorithm (RAAV), which shortens the sensed AV interval (SAV) at faster atrial rates, was programmed to provide a physiologic SAV with exercise. She developed repetitive, atypical, long-RP pacemaker-mediated tachycardia (PMT) because the RAAV shortened the antegrade SAV and retrograde conduction occurred over the slow AV nodal pathway. PMT was refractory to usual programming solutions. Using high-density electroanatomic mapping, we were able to ablate the retrograde limb of PMT without further damaging AV conduction.

Preoperative Radiographic Parameters to Predict a Higher Pseudarthrosis Rate After Anterior Cervical Discectomy and Fusion.

STUDY DESIGN: Retrospective study. OBJECTIVE: To determine whether postoperative pseudarthrosis can be predicted from specific preoperative radiograph measurements. SUMMARY OF BACKGROUND DATA: Various factors reportedly influence the occurrence of pseudarthrosis after anterior cervical discectomy and fusion (ACDF). However, to our knowledge, there are no reports on the relationships between preoperative radiographic parameters and pseudarthrosis. METHODS: We analyzed 84 consecutive patients (45 males, 39 females, mean age, 58.9 ±â€Š11.2 yrs) who underwent ACDF. In all patients, allografts filled with local chip bone were inserted after discectomy and anterior plating was performed. On preoperative plain radiographs, we analyzed C2-C7 sagittal vertical axis, T1 sagittal slope, segmental motion, global cervical motion, and location of fusion segments. Pseudarthrosis was diagnosed as interspinous motion >1 mm with superjacent interspinous motion ≥4 mm on magnified dynamic lateral radiographs. Multivariate logistic regression was used to analyze the risk factors for pseudarthrosis and the receiver operating characteristic (ROC) curve was used to define a cutoff value. RESULTS: One hundred and twenty-five segments from 84 patients were included. The pseudarthrosis rate was 29% based on number of patients (24/84) and 20% based on number of segments (25/125). Multilevel surgery and segments at the lowest levels showed higher pseudarthrosis rates (P = 0.01). Per multivariate logistic regression analysis, greater preoperative segmental motion, greater preoperative T1 sagittal slope, and C6-7 segments were associated with a higher risk of pseudarthrosis (all P < 0.05). A segmental motion cutoff value of 12° demonstrated pseudarthrosis with sensitivity of 87%, specificity of 84%, and area under the curve of 0.899, indicating moderate accuracy. CONCLUSION: Greater preoperative segmental motion, greater preoperative T1 sagittal slope, and lower fusion levels could be risk factors for pseudarthrosis following ACDF. Preoperative segmental motion >12° is likely to be an important indicator of the development of pseudarthrosis. LEVEL OF EVIDENCE: 3.

Effect of gemigliptin on glycaemic variability in patients with type 2 diabetes (STABLE study).

The aim of this study was to evaluate the effect of gemigliptin vs sitagliptin or glimepiride as initial combination therapy with metformin on glycaemic variability and to assess the correlation between glycaemic variability reduction and the dipeptidyl peptidase-4 (DPP-4) inhibition in patients with type 2 diabetes. This multicentre, randomized, active-controlled, open-label exploratory study included 69 patients with HbA1c > 7.5%. Subjects were randomized to receive gemigliptin 50 mg (n = 24), sitagliptin 100 mg (n = 23) or glimepiride 2 mg (n = 22) for 12 weeks. After 12 weeks, the change in mean amplitude of glycaemic excursion (MAGE) compared with baseline was significantly lower in the DPP-4 inhibitor groups compared with that in patients who received glimepiride. Furthermore, the standard deviation (SD) of glucose was significantly lower in patients who received gemigliptin than that in patients who received sitagliptin or glimepiride. The DPP-4 inhibition was significantly correlated with changes in MAGE and SD of glucose. In conclusion, gemigliptin and sitagliptin were more effective than glimepiride in reducing glycaemic variability as initial combination therapy with metformin in patients with type 2 diabetes, and the DPP-4 inhibition was associated with a reduction in glycaemic variability.

Effect of the Pillar implant on snoring and mild obstructive sleep apnea: A multicenter study in Korea.

OBJECTIVES/HYPOTHESIS: The effect of the Pillar implant on mild sleep-disordered breathing (SDB) has been assessed in various studies. However, most of these were conducted among a non-Asian population at a single institution. Therefore, the aim of this study was to prospectively evaluate the efficacy of the Pillar implant in Asian patients with simple snoring and mild obstructive sleep apnea (OSA) at multiple centers. STUDY DESIGN: Multicenter prospective clinical trials. METHODS: This study included consecutive subjects with simple snoring or mild OSA. We examined subjective symptoms (snoring intensity, frequency, witnessed apnea, and daytime sleepiness) and objective snoring and respiratory parameters (snoring duration [proportion of sleep while snoring louder than 50 dB], snoring loudness, apnea-hypopnea index, respiratory disturbance index, minimum arterial oxygen saturation, and oxygen desaturation index ≥ 4%) at 3 to 6 months after surgery. Adverse events were also investigated. RESULTS: Twenty-nine subjects with mild SDB completed the study. Whole group analysis found significant improvements in various subjective symptoms, but not in the objective snoring and respiratory parameters. A subgroup analysis of subjects with mild OSA (n = 11) found significant alleviation in various subjective symptoms, apnea-hypopnea index, respiratory disturbance index, and oxygen desaturation index ≥ 4%. No major complication related to surgery was observed, and most minor adverse effects were resolved without morbidity. CONCLUSIONS: In selected Korean patients, the Pillar implant significantly improved not only subjective symptoms of mild SDB but also respiratory disturbances in mild OSA. LEVEL OF EVIDENCE: 2b.

How long should patients remain in the supine treatment position after intratympanic dexamethasone injection?

OBJECTIVES/HYPOTHESIS: Intratympanic dexamethasone injection (ITDI) is a widely accepted treatment for patients with sudden hearing loss. We investigated the appropriate patient wait time in the supine treatment position after ITDI. STUDY DESIGN: Prospective study. METHODS: In an in vivo animal study, 24 mice were injected intratympanically with dexamethasone. Perilymphatic fluid was sampled at 5, 10, 15, 20, 25, and 30 minutes postinjection. The dexamethasone concentration was analyzed using high-performance liquid chromatography. In a separate prospective clinical study, 79 patients with refractory sudden hearing loss underwent intratympanic injection. After the injection, patients remained in the supine position with the head rotated 45° to the unaffected side. Patients were divided into two groups according to the wait time in this treatment position postinjection: 30 minutes (n = 47) and 10 minutes (n = 32). Final hearing assessments were conducted 2 months after salvage treatment. RESULTS: In the in vivo animal study, the perilymphatic concentration of dexamethasone showed no significant increase after 10 minutes. In the clinical setting, hearing improvement according to Siegel's criteria was similar in the 30-minute (14/47) and 10-minute (10/32) groups (P = 0.999). No significant differences in relative hearing gain was observed between the two groups (13.80 ± 19.9 dB and 12.57 ± 14.9 dB, respectively; P = 0.766). CONCLUSION: We suggest that 10 minutes is a sufficient time to remain in the supine treatment position after ITDI in patients with sudden hearing loss. LEVEL OF EVIDENCE: N/A.

How to resolve the caudal septal deviation? Clinical outcomes after septoplasty with bony batten grafting.

OBJECTIVES/HYPOTHESIS: Caudal septal deviation interrupts normal nasal breathing, due to the narrowing of the external valve area and nasal valve angle. In this study, we found a different approach for correction of caudal septal deviation with no associated deformity of the external nose. STUDY DESIGN: Individual case-control study. METHODS: The 39 patients completed questionnaires by interviews postoperatively for assessment of nasal obstruction. In addition, patients assessed the severity of their nasal symptoms (i.e., mouth breathing, mouth dryness, hyposmia, rhinorrhea, epistaxis, snoring, postnasal drip, and headache) preoperatively and postoperatively using a visual analog scale (VAS). Improvement in the treatment of nasal obstruction using a VAS and a questionnaire for subjective satisfaction were evaluated 3 months after septoplasty. To evaluate outcomes objectively, endoscopic photographs of the nasal cavity and acoustic rhinometry before and after surgery were evaluated. For comparison between preoperative and postoperative status, the Wilcoxon signed ranks test was used. RESULTS: Patients reported a significant decrease in the VAS severity of all nasal symptoms. The minimal cross-sectional area (MCA1) of the convex side after vascular constriction using acoustic rhinometry showed significant widening. Patients were divided into a turbinoplasty group and a nonturbinoplasty group, and the turbinoplasty group showed a significant increase in both the convex side and concave side in MCA1 and in the convex side in the anterior portion of the inferior turbinate. CONCLUSIONS: Endonasal septoplasty using bony batten grafting for caudal septal deviation resulted in an improvement of nasal obstruction symptoms and acoustic rhinometry components.

Barefoot stubbing injuries to the great toe in children: a new classification by injury mechanism.

OBJECTIVE: This study was conducted to categorize barefoot stubbing injuries to the great toe in children by injury mechanism to differentiate benign stubbing injuries from more complex injuries necessitating surgery. DESIGN: Prospective clinical series of consecutively treated patients. SETTING: Tertiary university hospital setting. PATIENTS: Forty-one children who had sustained an indirect injury to the great toe during barefoot sports activities between January 2001 and December 2009 were included. INTERVENTION: Conservative or surgical treatment was done according to clinical and radiological findings. MAIN OUTCOME MEASUREMENT: Information regarding injury mechanism was collected from patients, parents, and coaches using skeletal models and assessed by a pediatric orthopedic surgeon. Mechanisms of injury were identified and grouped as follows: hyperabduction-flexion, hyperflexion, hyperabduction-extension, hyperextension, and hyperextension-adduction. RESULTS: Hyperabduction-flexion was the most common mechanism (n = 16), in which interphalangeal joint dislocation and skin disruption was noted in most cases. The second most common mechanism was hyperabduction-extension (n = 14) in which avulsion fracture of the lateral volar condyle of the proximal phalanx was noted in most cases. This avulsion fracture had the worst prognosis after conservative care. CONCLUSIONS: Based on these results, we have created a grading system and treatment protocol for indirect hallux sports injuries in children. Avulsion fracture of the lateral condyle of the proximal phalanx, a result of hyperabduction-extension, is a high-risk sign of nonunion and should be aggressively treated, contrary to previous guidelines. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Pellegrini-Stieda disease: a heterogeneous disorder not synonymous with ossification/calcification of the tibial collateral ligament-anatomic and imaging investigation.

OBJECTIVE: Ossification/calcification around the medial femoral condyle has been known as Pellegrini-Stieda (PS) disease for almost 100 years. Little attention has been given to magnetic resonance (MR) imaging characteristics. Our purpose is to demonstrate the anatomy in the medial femoral compartment and imaging findings of PS disease, determining the sites and patterns of ossification. DESIGN AND PATIENTS: In a cadaveric study seven specimens were dissected to show the anatomic relations of the tibial collateral ligament (TCL) and the tendon of the ischiocondylar part of the adductor magnus muscle, in the medial femoral epicondyle. In order to determine the nature of ossification/calcification in PS disease, MR imaging and radiographic findings in nine patients were analyzed by two observers with attention to the specific site, shape, and orientation of the ossification and its relationship to the tibial collateral ligament (TCL) and adductor magnus tendon. Available clinical history was recorded. A classification system addressing different sites and patterns of ossification was developed. RESULTS: The anatomic study showed that the TCL and the adductor magnus tendon insert at different sites in the medial femoral condyle and there is no continuation; however, some fibers of the posterior bundle of the TCL overlap the anterior aspect of the adductor magnus tendon. The imaging study showed that shape, orientation, and location of the abnormal calcification and ossification were similar on radiographic and MR imaging analysis. Ossification had an inferior orientation in six cases, a superior orientation in two cases, and both in one case. Four patterns of ossification were noted: (I) a beak-like appearance with an inferior orientation and femoral attachment was present in five cases; (II) a drop-like appearance with an inferior orientation, parallel to the femur, was evident in one case; (III) an elongated appearance with a superior orientation, parallel to the femur, was seen in two cases; and (IV) a beak-like appearance with an inferior and superior orientation, attached to the femur, was seen in one case. The ossification was present in the TCL in six cases, in the adductor magnus tendon in two cases, and in both in one case. The coronal plane was best in detecting and categorizing the ossification. CONCLUSION: Our data indicate that ossification in PS disease is not confined to the TCL but may also involve the adductor magnus tendon. In some cases, it can be related to the anatomic proximity (overlap) of the fibers of these two structures. PS disease should not be regarded as synonymous with ossification of the TCL. The ossification may be classified into four types. No clinical differences among these types appear to exist.

Mass production of methane from food wastes with concomitant wastewater treatment.

We developed a process for production of methane at a pilot scale. This process consists of three stages. The first stage is a semianaerobic hydrolysis/acidogenic step in which organic wastes are converted to various sugars, amino acids, and volatile fatty acids (VFAs). Operation temperature and pH were 45 degrees C, and 5.0-5.5, respectively. Hydraulic retention time (HRT) was 2 d. To remove the putrid odor and to enhance the hydrolysis of organic wastes, a mixture of bacteria isolated from landfill soil was inoculated into the reactor. Total chemical oxygen demand (tCOD) and biological oxygen demand (BOD) were 36,000 mg/L and 40,000 mg/L, respectively. The second stage was an anaerobic acidogenic process, which can produce large amount of VFAs including acetate, propionate, butyrate, valerate, and caproate. Operation temperature and pH were 35 degrees C, and 5.0-5.5, respectively. HRT was 2 d. The third stage was a strictly anaerobic methane fermentation step producing methane and carbon dioxide from VFAs. The working volume of upflow anaerobic sludge blanket (UASB) type reactor was 1200 L, and operation temperature and pH were 41 degrees C, and 7.7-7.9, respectively. HRT was 12 d. Seventy two percent of methane at maximum was generated and the yield was 0.45-0.50 m3/kgVS of food wastes. Through the process, 88% of tCOD and 95% of BOD were removed. The wastewater was treated with the biological aerobic and anaerobic filters immobilized with heterotrophic and autotrophic nitrifying and denitrifying bacteria. Ninety percent of total nitrogen (T-N) was removed by this treatment. The residual T-N and total phosphorous (T-P) were removed by the algal periphyton treatment system. The final concentrations of nitrogen and phosphorous in the drain water were 53 and 7 mg/L, respectively.