Stabilization Mechanism of Roxithromycin Tablets Under Gastric pH Conditions

Macrolide antibiotics are widely used at clinical sites. Clarithromycin (CAM), a 14-membered macrolide antibiotic, was reported to gelate under acidic conditions. Gelation allows oral administration of acid-sensitive CAM without enteric coating by hindering the penetration of gastric fluid into CAM tablets. However, it is unknown whether this phenomenon occurs in other macrolide antibiotics. In this study, we examined the gelation ability of 3 widely used macrolide antibiotics, roxithromycin (RXM), erythromycin A, and azithromycin. The results indicated that not only CAM but also RXM gelated under acidic conditions. Erythromycin A and azithromycin did not gelate under the same conditions. Gelation of RXM delayed the disintegration of the tablet and release of RXM from the tablet. Disintegration and release were also delayed in commercial RXM tablets containing disintegrants. This study showed that 2 of the 4 macrolides gelated, which affects tablet disintegration and dissolution and suggests that this phenomenon might also occur in other macrolides.     

An immunohistochemical and ultrastructural study of the pericellular matrix of uneroded hypertrophic chondrocytes in the mandibular condyle of aged c-src-deficient mice

OBJECTIVE: Previous studies indicate that hypertrophic chondrocytes can transdifferentiate or dedifferentiate and redifferentiate into bone cells during the endochondral bone formation. Mandibular condyle in aged c-src-deficient mice has incremental line-like striations consisting of cartilaginous and non-cartilaginous layers, and the former contains intact hypertrophic chondrocytes in uneroded lacunae. The purpose of this study is to determine the phenotype changes of uneroded hypertrophic chondrocytes. DESIGN: Immunohistochemical and ultrastructural examinations of the pericellular matrix of hypertrophic chondrocytes in the upper, middle, and lower regions of the mandibular condyle were conducted in aged c-src-deficient mice, using several antibodies of cartilage/bone marker proteins. RESULTS: Co-localisation of aggrecan, type I collagen, and dentin matrix protein-1 (DMP-1) or matrix extracellular phosphoprotein (MEPE) was detected in the pericellular matrix of the middle region. Ultrastructurally, granular substances in the pericellular matrix of the middle region were the remains of upper region chondrocytes, which were mixed with thick collagen fibrils. In the lower region, the width of the pericellular matrix and the amount of collagen fibrils were increased. Versican, type I collagen, DMP-1, and MEPE were detected in the osteocyte lacunae. Additionally, DMP-1 and MEPE were detected in the pericellular matrix of uneroded hypertrophic chondrocytes located in the lower, peripheral region of the mandibular condyle in younger c-src-deficient mice, but not in the aged wild-type mice. CONCLUSIONS: These results indicate that long-term survived, uneroded hypertrophic chondrocytes, at least in a part, acquire osteocytic characteristics.     

Congenital absence of the permanent canines: a clinico-statistical study

We report here a clinico-statistical study of congenital absence of the permanent canines (CAPC). Sixty-five cases (22 men and 43 women) of CAPC were found in the files of 35,927 outpatients, an incidence of 0.18%. Thirty-seven cases had single absence of the canine and 28 cases had multiple absences. There were 42 cases in the maxilla, 17 in the mandible, and 6 in both the maxilla and the mandible. In the single absence cases, there was a tendency of occurrence at the left side in the maxilla, and the right side in the mandible. There were 39 CAPC cases without absence of other permanent teeth. Several complicated dental anomalies were seen such as persistence of deciduous teeth, congenital absence of other permanent teeth, microdontia, malposition, and complete or incomplete impaction (excluding the third molars). The complication rate of other permanent tooth absences was higher in the cases with CACP in the maxilla than in the mandible.     

Laparoscopic trans-peritoneal hernioplasty (TAPP) is useful for obturator hernias: report of a Case

A 71-year-old female presented to our hospital due to pain from the right hip joint to the lower abdomen. The pain had suddenly appeared and spontaneously disappeared more than 10 times during the past 2 years. She had visited many hospitals, but remained undiagnosed. The patient underwent a computed tomography (CT) scan of the pelvis, and a soft tissue shadow was seen between the external obturator and pectineal muscles. She was diagnosed with a right obturator hernia and underwent elective repair by laparoscopic trans-peritoneal hernioplasty (TAPP). 1 year has passed since the surgery, without any recurrence of the abdominal pain. Obturator hernias are rare, and most cases are found as incarcerated hernias. It is rare to find an obturator hernia without intestinal obstruction, or with the recurrent pain as in our case. We herein report a case in which an obturator hernia was undiagnosed and intermittent pain was experienced for 2 years prior to TAPP, which appears to have successfully treated the hernia.     

Factors related to the incidence of anterior disc displacement without reduction and bony changes of the temporomandibular joint in patients with anterior open bite

Purpose

We aimed to investigate factors related to the prevalence of anterior disc displacement without reduction (ADDwoR) and bony changes of the condylar head (bony changes) in the temporomandibular joints (TMJs) of patients with anterior open bite.

Methods

Subjects are comprised of 36 preoperative patients (72 joints) with skeletal anterior open bite without facial asymmetry who had undergone orthognathic surgery at the Hokkaido University Hospital; magnetic resonance imaging of the TMJ and cephalometric analysis were performed before treatment. Logistic regression analysis was performed to clarify relationships among age, overbite, overjet, ANB angle, sella to nasion (SN) to mandibular plane angle (SN–MP angle), SN to ramus plane angle (GZN angle), gonial angle, and incidence of ADDwoR or bony changes in patients with anterior open bite.

Results

Fifteen patients had bilateral ADDwoR, and five patients had unilateral ADDwoR; 17 patients had bilateral bony changes, and five patients had unilateral bony changes. SN–MP angle was greater in 20 patients with ADDwoR than that in 16 patients without ADDwoR (p?p?Conclusion In terms of dentofacial morphology, SN–MP angle appears to be associated with the incidence of ADDwoR, and GZN angle appears to be associated with bony changes in the TMJ.