Regenerative capacity of augmented bone in rat calvarial guided bone augmentation model

PURPOSE: Guided bone regeneration (GBR) is the most widely used technique to regenerate and augment bones. Even though augmented bones (ABs) have been examined histologically in many studies, few studies have been conducted to examine the biological potential of these bones and the healing dynamics following their use. Moreover, whether the bone obtained from the GBR procedure possesses the same functions as the existing autogenous bone is uncertain. In particular, little attention has been paid to the regenerative ability of GBR bone. Therefore, the present study histologically evaluated the regenerative capacity of AB in the occlusive space of a rat guided bone augmentation (GBA) model. METHODS: The calvaria of 30 rats were exposed, and plastic caps were placed on the right of the calvaria in 10 of the 30 rats. After a 12-week healing phase, critical-sized calvarial bone defects (diameter: 5.0 mm) were trephined into the dorsal parietal bone on the left of the calvaria. Bone particles were harvested from the AB or the cortical bone (CB) using a bone scraper and transplanted into the critical defects. RESULTS: The newly generated bone at the defects' edge was evaluated using micro-computed tomography (micro-CT) and histological sections. In the micro-CT analysis, the radiopacity in both the augmented and the CB groups remained high throughout the observational period. In the histological analysis, the closure rate of the CB was significantly higher than in the AB group. The numbers of cells positive for runt-related transcription factor 2 (Runx2) and tartrate-resistant acid phosphatase (TRAP) in the AB group were larger than in the CB group. CONCLUSIONS: The regenerative capacity of AB in the occlusive space of the rat GBA model was confirmed. Within the limitations of this study, the regenerative ability of the AB particulate transplant was inferior to that of the CB particulate transplant.

Small Intestinal Bacterial Overgrowth in Patients with Refractory Functional Gastrointestinal Disorders

BACKGROUND/AIMS: Small intestinal bacterial overgrowth (SIBO) is considered to be involved in the pathogenesis of functional gastrointestinal disorders (FGID). However, the prevalence and clinical conditions of SIBO in patients with FGID remain to be fully elucidated. Here, we examined the frequency of SIBO in patients with refractory FGID. METHODS: We prospectively enrolled patients with refractory FGID based on Rome III criteria. A glucose hydrogen breath test (GHBT) was performed using a gas analyzer after an overnight fast, with breath hydrogen concentration measured at baseline and every 15 minutes after administration of glucose for a total of 3 hours. A peak hydrogen value > or = 10 ppm above the basal value between 60 and 120 minutes after administration of glucose was diagnosed as SIBO. RESULTS: A total of 38 FGID patients, including 11 with functional dyspepsia (FD), 10 with irritable bowel syndrome (IBS), and 17 with overlapping with FD and IBS, were enrolled. Of those, 2 (5.3%) were diagnosed with SIBO (one patient diagnosed with FD; the other with overlapping FD and IBS). Their symptoms were clearly improved and breath hydrogen levels decreased to normal following levofloxacin administration for 7 days. CONCLUSIONS: Two patients initially diagnosed with FD and IBS were also diagnosed with SIBO as assessed by GHBT. Although the frequency of SIBO is low among patients with FGID, it may be important to be aware of SIBO as differential diagnosis when examining patients with refractory gastrointestinal symptoms, especially bloating, as a part of routine clinical care.