Proteolytic activation and glycosylation of N-acylethanolamine-hydrolyzing acid amidase, a lysosomal enzyme involved in the endocannabinoid metabolism.

N-acylethanolamine-hydrolyzing acid amidase (NAAA) is a lysosomal enzyme hydrolyzing bioactive N-acylethanolamines, including anandamide and N-palmitoylethanolamine. Previously, we suggested that NAAA is glycosylated and proteolytically cleaved. Here, we investigated the mechanism and significance of the cleavage of human NAAA overexpressed in human embryonic kidney 293 cells. Western blotting with anti-NAAA antibody revealed that most of NAAA in the cell homogenate was the cleaved 30-kDa form. However, some of NAAA were released outside the cells and the extracellular enzyme was mostly the uncleaved 48-kDa form. When incubated at pH 4.5, the 48-kDa form was time-dependently converted to the 30-kDa form with concomitant increase in the N-palmitoylethanolamine-hydrolyzing activity. The purified 48-kDa form was also cleaved and activated. However, the cleavage did not proceed at pH 7.4 or in the presence of p-chloromercuribenzoic acid. The mutant C126S was resistant to the cleavage and remained inactive. These results suggested that this specific proteolysis is a self-catalyzed activation step. We next determined N-glycosylation sites of human NAAA by site-directed mutagenesis addressed to asparagine residues in six potential N-glycosylation sites. The results exhibited that Asn-37, Asn-107, Asn-309, and Asn-333 are actual N-glycosylation sites. The glycosylation appeared to play an important role in stabilizing the enzyme protein.

Effects of alendronate on the removal torque of implants in rats with induced osteoporosis.

PURPOSE: In this study, the removal torques of commercially pure titanium Implants that had been implanted simultaneously with the start of treatment for osteoporosis were compared to those of a group without treatment and a healthy group. MATERIALS AND METHODS: Rats treated by ovariectomy or sham surgery at the age of 12 weeks were used. Twenty-eight days after surgery, the rats treated by ovariectomy were divided into an alendronate-treated group and an untreated (ovariectomy-control) group. At the start of administration of alendronate, a titanium implant was placed in the distal metaphysis of the femur. After 1 month of administration of alendronate and a vehicle, removal torque, the percentage of bone-implant contact (BIC), and parameters of treatment using alendronate were measured. RESULTS: The removal torque values were 10.1 +/- 1.6 Ncm for the group of osteoporotic rats that had been administered alendronate and 6.4 +/- 1.0 Ncm for the group of osteoporotic rats that did not receive alendronate, indicating that the removal torque was significantly higher in the former group than in the latter group. However, there was no significant difference between the alendronate-treated group and the healthy control group (ie, sham surgery) (9.3 +/- 1.3 Ncm). DISCUSSION AND CONCLUSION: These results suggested that implant placement together with treatment of osteoporosis is possible in the ovariectomized rat model.

[Clinical study of the area under the blood concentration-time curve of targeting intra-arterial infusion chemotherapy with nedaplatin for primary oral cancer].

We treated oral cancer using a targeting intra-arterial infusion chemotherapy with CDGP (nedaplatin); dosages were determined by the original formula. We compared the expected AUC (area under the curve) with the actual AUC in primary oral cancer cases to assess the optimal dosage of CDGP for intra-arterial chemotherapy and to study relevance of AUC, effectiveness of independent chemotherapy and side effects. Eleven cases were treated at the Department of Oral and Maxillofacial Surgery, Faculty of Medicine, Kagawa Medical University, from October 1998 to June 2002. The results are as follows. 1) A correlation was seen between the AUC and degree of thrombocytopenia. 2) AUC may reveal renal function, especially for GFR. 3) The response rate of the targeted intra-arterial infusion chemotherapy with CDGP was remarkably high and serious side effects were not observed. It appears that the set-up of the optimum dose should be decided based on the actual AUC. 4) There was about a 4/3 difference between the value of the expected AUC and the actual AUC. The equation for dosages based on the actual AUC needs to be studied further.

[Clinical study for determination of the dosage formula for intra-arterial infusion chemotherapy with nedaplatin].

Area under the curve (AUC) is a very important parameter for determination of optimal dosage of antineoplastic agents in order to avoid side effects and achieve high effectiveness. Also, even if a certain dosage is administered, measured AUC is different in each individual. Therefore, it is important to determine the formula of the dosage of antineoplastic agents. We treated oral cancer using an intra-arterial infusion chemotherapy with nedaplatin (CDGP). Eighteen patients were treated with CDGP at the Department of Oral and Maxillofacial Surgery, Faculty of Medicine, Kagawa Medical University, from October 1998 to June 2002. The correlation among expected AUC, dosage, CDGP clearance and 24 hr creatinine clearance in all chemotherapy was monitored and examined. The obtained formula in the dosage of intra-arterial infusion chemotherapy with Nedaplatin was as follows. dosage = AUC x (0.027 x CCr + 7.17).

Risk Factors for Methicillin-Resistant Staphylococcus aureus (MRSA) and Use of a Nasal Mupirocin Ointment in Oral Cancer Inpatients.

PURPOSE: Elimination of methicillin-resistant Staphylococcus aureus (MRSA) is of critical importance in oral and maxillofacial surgery because control is very difficult once infection of an oral tumor or oral wound with MRSA is established. PATIENTS AND METHODS: We retrospectively investigated the risk factors for acquiring MRSA in 518 patients with oral cancer among 1,877 inpatients in our department between 1984 and 2005. RESULTS: The patients with oral cancer demonstrated a high rate of MRSA colonization and infection (77.8%) relative to the population as a whole with MRSA isolated percentage in our department after 1991. The risk factors for MRSA in oral cancer patients are also related to systemic diseases and physiological and iatrogenic conditions, including cerebrovascular diseases (77.8%), peripheral arterial catheterization (69.2%), diabetes (50.0%), tracheotomy (50.0%), renal failure (50.0%), long-term broad-spectrum antibiotic use (45.7%), and malnutrition (43.3%). However, the highest risk of MRSA seems to be related to poor hygienic care. CONCLUSIONS: Beginning in 1999, we implemented a strategy for reducing infection by MRSA that included nasal mupirocin ointment for patients at high risk of MRSA; since then, the detection rate has decreased. We suggest that the administration of nasal mupirocin ointment and provision of scrupulous hygienic care for high-risk patients are useful and effective measures for decreasing the incidence of MRSA infection.