No abstract

Reconstruction of oral defects using flaps following resection of oral cancer has become a standard approach for restoration of oral function. The purpose of this study was to investigate chronological changes in the volume of such flaps used for reconstruction and the factors affecting flap volume. We performed a retrospective analysis of 17 patients who had undergone oral cancer resection and reconstruction with flaps. Measurements were performed using data from computed tomography, and the flaps were selected semi-automatically using a computer-operated region-of-interest system. The data indicated that the change in total flap volume at 1 year after surgery was 30.6%, and that body weight loss was a risk factor for volume reduction. Our results suggested that flaps should be at least 30% larger than the defects they are intended to repair. However, as large flaps have the potential to cause upper airway obstruction, flap volume should be determined on an individual basis according to defect size and location.

A patient with a mild bleeding disorder whose platelets responded defectively to thromboxane A2 (TXA2) was identified, and the mechanism of this dysfunction was analyzed. The platelets were defective in shape change, aggregation, and release reaction in response to synthetic TXA2 mimetic (STA2). When the platelet TXA2 receptor was examined with both a 125I-labeled derivative of a TXA2 receptor antagonist ([125I]-PTAOH) and [3H]-labeled TXA2 agonist ([3H]U-46619), the equilibrium dissociation rate constants (kd) and the maximal concentrations of binding sites (Bmax) of the platelets to both ligands were within normal ranges, suggesting that the binding capacity of their TXA2 receptor was normal. STA2 could not induce IP3 formation and intracellular Ca2+ mobilization, whereas these responses to thrombin were within normal ranges. GTPase activity was also decreased when the patient's platelet membrane was challenged with STA2. On the other hand, lysophosphatidylinositol formation, which is a direct indicator of phospholipase A2 (PLA2) activation, was found to be normal when the [3H]-inositol-labeled platelets were challenged with STA2. Thromboxane B2 (TXB2) was also produced in response to STA2. These results suggested that the abnormality in these platelets was impaired coupling between TXA2 receptor and phospholipase C (PLC) activation. Furthermore, it is also suggested that the activation of PLA2 and PLC are separable events in thromboxane-induced platelet activation.

Cleidocranial dysplasia (CCD; MIM 119600) is an autosomal dominant skeletal dysplasia characterised by hypopalstic and/or aplastic clavicles, midface hypoplasia, absent or delayed closure of cranial sutures, moderately short stature, delayed eruption of permanent dentition and supernumerary teeth. The molecular pathogenesis can be explained in about two-thirds of CCD patients by haploinsufficiency of the RUNX2 gene. In our current study, we identified a novel and rare variant of the RUNX2 gene (c.181_189dupGCGGCGGCT) in a Japanese patient with phenotypic features of CCD. The insertion led an alanine tripeptide expansion (+3Ala) in the polyalanine tract. To date, a RUNX2 variant with alanine decapeptide expansion (+10Ala) is the only example of a causative variant of RUNX2 with polyalanine tract expansion to be reported, whilst RUNX2 (+1Ala) has been isolated from the healthy population. Thus, precise analyses of the RUNX2 (+3Ala) variant were needed to clarify whether the tripeptide expanded RUNX2 is a second disease-causing mutant with alanine tract expansion. We therefore investigated the biochemical properties of the mutant RUNX2 (+3Ala), which contains 20 alanine residues in the polyalanine tract. When transfected in COS7 cells, RUNX2 (+3Ala) formed intracellular ubiquitinated aggregates after 24h, and exerted a dominant negative effect in vitro. At 24h after gene transfection, whereas slight reduction was observed in RUNX2 (+10Ala), all of these mutants significantly activated osteoblast-specific element-2, a cis-acting sequence in the promoter of the RUNX2 target gene osteocalcin. The aggregation growth of RUNX2 (+3Ala) was clearly lower and slower than that of RUNX2 (+10Ala). Furthermore, we investigated several other RUNX2 variants with various alanine tract lengths, and found that the threshold for aggregation may be RUNX2 (+3Ala). We conclude that RUNX2 (+3Ala) is the cause of CCD in our current case, and that the accumulation of intracellular aggregates in vitro is related to the length of the alanine tract.

Background: The serum concentration of unbound bilirubin (UB), which is bilirubin not bound to albumin (Alb), is a better index than total bilirubin concentration (TB) for identifying infants at risk for developing bilirubin neurotoxicity. The degree to which the hypoalbuminemia following abdominal surgery in jaundiced newborns affects bilirubin binding is unknown. Objective: To determine whether lower Alb occurring in newborns undergoing abdominal surgery shortly after birth results in significantly higher UB in serum versus nonsurgical patients at comparable serum TB. Methods: A matched case-control study was conducted with term and late-preterm newborns. The surgery group included 15 newborns who underwent abdominal operation within 3 days after birth. Clinical and laboratory data (serum UB, TB, and Alb concentrations, UB/TB ratio, and binding constant) in the surgery group were collected and compared with those of 30 control newborns who did not undergo abdominal surgery (control group). Results: Serum UB and the UB/TB ratio in the surgery group were significantly higher than those in the control group (p < 0.02, p < 0.001, respectively), whereas there were no significant differences in serum TB and binding constant between the groups. Serum Alb concentrations in the surgery group were significantly lower than those in the control group (p < 0.001). When pre- and postoperative serum Alb concentrations were compared, there was a significant decrease from 3.4 to 2.7 g/dl (p < 0.001). Conclusions: Our study suggests that hypoalbuminemia following abdominal surgery causes a higher serum UB at comparable serum TB in newborns.