The influence of oral VPA on the required dose of propofol for sedation during dental treatment in patients with mental retardation: a prospective observer-blinded cohort study.

In sedation of dental patients with moderate or severe mental retardation, it is difficult to identify the optimum sedation level and to maintain it appropriately. Moreover, many patients have concomitant epilepsy and are medicated with oral antiepileptic drugs (AEDs), which influence the drug-metabolizing enzymes. In particular, valproate (VPA) has been demonstrated to inhibit propofol metabolism in vitro. Therefore, the objective of the present study was to investigate the clinical influence of oral VPA on the required dose of propofol for sedation, with use of a prospective cohort study design. We studied 45 patients with moderate or severe mental retardation who underwent dental treatment under sedation. Propofol was infused, and sedation was maintained at the same level in all patients using a bispectral index (BIS) monitor. After the completion of treatment for the scheduled patients, patients were divided into those with oral VPA treatment (VPA group: 20 patients) and without any oral antiepileptic treatment (control group: 25 patients). The propofol dose required for sedation and times to the recovery of the eyelash reflex and spontaneous eye opening were evaluated. The median required propofol doses in the VPA and control groups were 4.15 (range 1.97-5.88) and 5.67 (2.92-7.17) mg/kg/h, respectively. We observed a statistically significant difference between the two patient groups with respect to median VPA dose (p < 0.01). However, no statistically significant differences were noted in the time until eyelash reflex recovery or spontaneous eye opening between the two groups. The results suggest that oral VPA reduces the dose of propofol required for sedation during dental treatment in patients with moderate or severe mental retardation.

Extreme tooth abnormalities and treatment under general anesthesia in a child with chronic GVHD surviving relapse of acute lymphoblastic leukemia.

Treatment for acute lymphoblastic leukemia (ALL) mainly consists of chemotherapy, irradiation and bone marrow transplantation. In terms of long-term treatment effects, dental abnormalities and chronic graft-versus host disease (GVHD) are problems. We present a patient surviving relapse of ALL at one year of age. He had extreme dental abnormalities and multiple caries. Most of his permanent teeth were abnormal, and multiple caries were observed. Since he had a strong vomiting reaction to dental treatment, general anesthesia was given. During the general anesthesia, much sputum was aspirated because of chronic GVHD. His dental condition was worse than other cases reported previously. Since the survival rate has increased recently, the dental effects of ALL treatment have become significant. Especially, in patients undergoing total body irradiation at under 2 years of age, it is highly likely that dental problems will occur in the future.

Propofol increases the rate of albumin-unbound free midazolam in serum albumin solution.

Propofol and midazolam have a synergistic anesthetic action. One of the reasons for this is thought to be the inhibitory effect of propofol on midazolam metabolism. However, because both drugs bind strongly to serum protein, their interaction may not only involve the effects of propofol on midazolam metabolism, but may also involve propofol's effects on serum protein-binding. Against this background, we investigated the characteristics of midazolam binding to serum albumin, and evaluated the effects of both propofol and ketamine on this binding. Midazolam was added to a serum albumin solution with propofol or ketamine, and, after incubation for 1 h, albumin-free solution was separated from the sample and the midazolam concentration was measured using a high-performance liquid chromatography system. The albumin-unbound rate of midazolam was evaluated and compared with the rate in the control solution (only midazolam). Propofol significantly raised the rate of albumin-unbound free midazolam, while ketamine had no effect on the binding of midazolam to serum albumin. These findings suggest that the increase in albumin-unbound free midazolam brought about by propofol is involved in the synergistic effect of these two agents.

Distinct adaptor proteins assist exit of Kre2-family proteins from the yeast ER.

The Svp26 protein of S. cerevisiae is an ER- and Golgi-localized integral membrane protein with 4 potential membrane-spanning domains. It functions as an adaptor protein that facilitates the ER exit of Ktr3, a mannosyltransferase required for biosynthesis of O-linked oligosaccharides, and the ER exit of Mnn2 and Mnn5, mannosyltransferases, which participate in the biosynthesis of N-linked oligosaccharides. Ktr3 belongs to the Kre2 family, which consists of 9 members of type-II membrane proteins sharing sequence similarities. In this report, we examined all Kre2 family members and found that the Golgi localizations of two others, Kre2 and Ktr1, were dependent on Svp26 by immunofluorescence microscopy and cell fractionations in sucrose density gradients. We show that Svp26 functions in facilitating the ER exit of Kre2 and Ktr1 by an in vitro COPII budding assay. Golgi localization of Ktr4 was not dependent on Svp26. Screening null mutants of the genes encoding abundant COPII membrane proteins for those showing mislocalization of Ktr4 in the ER revealed that Erv41 and Erv46 are required for the correct Golgi localization of Ktr4. We provide biochemical evidence that the Erv41-Erv46 complex functions as an adaptor protein for ER exit of Ktr4. This is the first demonstration of the molecular function of this evolutionally conserved protein complex. The domain switching experiments show that the lumenal domain of Ktr4 is responsible for recognition by the Erv41-Erv46 complex. Thus, ER exit of Kre2-family proteins is dependent on distinct adaptor proteins and our results provide new insights into the traffic of Kre2-family mannosyltransferases.

Allergic reactions to local anesthetics in dental patients: analysis of intracutaneous and challenge tests.

Some dental patients have histories of adverse reactions to local anesthesia. The aim of the present study was to investigate the frequency of allergy to local anesthetics of dental patients who had histories of adverse reactions to local anesthesia based on the results of allergy tests in our institute over a period of 5 years. We investigated the past medical records of dental patients retrospectively, and twenty patients were studied. Three of the 20 showed a positive or false-positive reaction in the intracutaneous test, and one patient showed a false-positive reaction in the challenge test. Our results suggest that the frequency of allergy to local anesthetics is low even if patients have histories of adverse reactions to local anesthesia. However, allergy tests of local anesthetics should be performed in patients in whom it is uncertain whether they are allergic.