Reconstruction using a submental island flap combined with mylohyoid muscle as a reliable surgical strategy after rim mandibulectomy for the management of stage 3 medication-related osteonecrosis of the mandible.

The purpose of this study was to evaluate the clinical outcomes of patients with stage 3 mandibular medication-related osteonecrosis of the jaw (MRONJ) treated using a submental island flap in combination with mylohyoid muscle reconstruction after rim mandibulectomy. The medical records of 12 patients treated between January 2019 and April 2022 were analysed retrospectively. Primary wound healing was assessed as the maintenance of full mucosal coverage without signs of infection at 6 months postoperatively. The follow-up period ranged from 7 to 38 months, with an average of 21.8 months. All 12 patients (100%) experienced primary wound healing, with normal mouth opening and occlusion, and without pathological mandibular fracture or facial aesthetic problems during the follow-up period. Postoperative panoramic images revealed new bone formation in the treated areas of the mandible in four patients. During the follow-up period, one patient continuing bevacizumab and zoledronate administration for the primary cancer developed MRONJ in the same area at 13 months postoperatively and finally died. Hence the total success rate was 91.7%. In summary, for patients with stage 3 mandibular MRONJ treated with rim mandibulectomy, the submental island flap combined with mylohyoid muscle is an effective reconstructive option for wound-healing and possible bone regeneration of denuded bone.

Orthodontic treatment of a unilateral impacted mandibular canine and first premolar: a case report.

BACKGROUND: Few dentists have seen an impacted mandibular canine and first premolar, and there is little information in the literature on the treatment of this rare condition. CASE REPORT: A 13-year-old Japanese male with an impacted mandibular right canine and first premolar was treated orthodontically. We discuss both the surgical and orthodontic options and present the successful orthodontic correction of a unilaterally impacted mandibular canine and first premolar.

Surgical approaches for condylar fractures related to facial nerve injury: deep versus superficial dissection.

The aim of this study was to investigate the probability of facial nerve injury (FNI) in the treatment of condylar neck and subcondylar fractures (CN/SCFs) with percutaneous approaches and to identify factors predicting FNI. The data of 80 patients with 87 CN/SCFs were evaluated retrospectively. The primary outcome was FNI occurrence. The predictor variables were age, sex, aetiology, alcohol consumption, fracture site and pattern (dislocation or not), concomitant fractures, time interval to surgery, surgeon experience, plate type, and the dual classification of percutaneous approaches. The approaches were classified based on whether subcutaneous dissection traversed the marginal mandibular branch (MMB) deeply (deep group: submandibular and retroparotid approaches) or superficially (superficial group: transparotid, transmasseteric anteroparotid (TMAP), and high cervical-TMAP approaches). Twenty-two patients (27.5%) suffered FNI, of whom two in the deep group had permanent paralysis of the MMB. In the multivariate logistic regression model, deeply traversing surgery approaches (odds ratio 12.4, P=0.025) and the presence of a dislocated fracture (odds ratio 6.66, P=0.012) were associated with an increased risk of FNI. These results suggest that percutaneous approaches in the superficial group should be recommended for the treatment of CN/SCFs to reduce the risk of FNI.

Orthodontic treatment for an unerupted and severely rotated maxillary central incisor. A case report.

BACKGROUND: Many reports have indicated the treatment for permanent teeth with disturbed eruption due to the presence of supernumerary teeth. However, successful treatment for an unerupted maxillary incisor with severe rotation and another maxillary incisor with disturbed eruption by a supernumerary tooth is quite rare. CASE REPORT: We treated a 7-year-old Japanese male with an unerupted and severely rotated maxillary right incisor, along with a maxillary left incisor due to interference with eruption by an inverted supernumerary tooth. Orthodontic treatment using surgical exposure, traction and guidance of the rotated right incisor, and maxillary expansion following extraction of the supernumerary tooth were performed. FOLLOW-UP: At 27 months following extraction of the supernumerary tooth, and comprehensive orthodontic treatment led the malposititioned central incisors to a functional position and stable occlusion.

Mode of action of gramicidin S on Escherichia coli membrane.

The action of a cationic antibiotic gramicidin S on the outer and cytoplasmic membranes of Escherichia coli was studied. It was found that gramicidin S disrupted the permeability barrier of the outer membrane, permitting the permeation of an antibiotic ionophore, this being similar to the action of the dimer in compound 48/80 (Katsu, T., Shibata, M. and Fujita, Y. (1985) Biochim. Biophys. Acta 818, 61-66). However, differently from the dimer, gramicidin S further stimulated the efflux of K+ through the cytoplasmic membrane of E. coli. The time course of K+ permeability change accorded well with that of change in the viability of E. coli cells. These changes occurred at temperatures above the phase transition of the cytoplasmic membrane. This temperature range differed greatly from the case of polymyxin B, a polycationic antibiotic acting at temperatures above the phase transition of the outer membrane. We discuss the mode of gramicidin S action on the cytoplasmic membrane of E. coli, in comparison with the results on red blood cells and liposomes.

Structure-activity relationship of gramicidin S analogues on membrane permeability.

The previous study of the action of gramicidin S on bacteria (Katsu, T., Kobayashi, H. and Fujita, Y. (1986) Biochim. Biophys. Acta 860, 608-619) prompted us to investigate further the structure-activity relationship of the gramicidin S analogues on membrane permeability. Two types of the gramicidin S analogues were used in the present study: (1) cyclo(-X-D-Leu-D-Lys-D-Leu-L-Pro-)2, where X = Gly, D-Leu and D-cyclohexylalanine (D-cHxAla); (2) N,N'-diacetyl derivative of gramicidin S (diacetyl-gramicidin S) which lacks a cationic moiety of gramicidin S. All the analogues have a beta-sheet conformation as gramicidin S. The following cellular systems were used: Staphylococcus aureus as Gram-positive bacteria, Escherichia coli as Gram-negative bacteria, human erythrocytes, rat liver mitochondria and artificial liposomal membranes. It was found that gramicidin S and one of the type 1 analogues having X = D-cHxAla induced the efflux of K+ through the cytoplasmic membrane of all types of the cells. In addition, these two peptides had the ability to lower the phase transition temperature of dipalmitoylphosphatidylcholine. Accordingly, it was concluded that, if peptides can expand greatly the membrane structure of neutral lipids which constitute main parts of the biological membrane, they can stimulate the permeability of cells without any selectivity. The action of the type 2 peptide, diacetyl-gramicidin S, was strongly cell dependent. Although this peptide stimulated the efflux of K+ from mitochondria, it did not do so efficiently, if at all, from S. aureus, E. coli and erythrocytes. In experiments using liposomes, diacetyl-gramicidin S increased markedly the permeability of liposomes composed of egg phosphatidylcholine. The presence of egg phosphatidylethanolamine or cholesterol reduced its activity. These results on liposomes explained well the low sensitivity of diacetyl-gramicidin S against E. coli and erythrocytes in terms of lipid constituents of the membranes. The mechanism of action of diacetyl-gramicidin S was discussed from the formation of a boundary lipid induced by this peptide.

Interaction of wasp venom mastoparan with biomembranes.

Mastoparan-induced changes in the K+ permeability of rat peritoneal mast cells, human erythrocytes, Staphylococcus aureus and Escherichia coli were examined. Mastoparan did not efficiently increase the K+ permeability of cells except for S. aureus. The release of membrane phospholipids was also observed from S. aureus cells in the concentration range of the permeability enhancement. Mastoparan stimulated histamine release from mast cells, independently of a small efflux of K+. Mastoparan became markedly effective to E. coli cells whose outer membrane structure was chemically disrupted beforehand, showing that the peptide can enhance the permeability of the cytoplasmic membranes of both Gram-positive and -negative bacteria. In experiments using liposomes, mastoparan increased the permeability of the liposomes composed of egg phosphatidylethanolamine and egg phosphatidylglycerol, which are the lipid constituents of the cytoplasmic membrane of E. coli cells, while it showed a weak activity to the liposomes composed of egg phosphatidylcholine and cholesterol. The latter result related closely to the fact that this peptide acted weakly on erythrocytes and mast cells in which acidic lipids constitute a minor portion. Mastoparan decreased the phase transition temperature of dipalmitoylphosphatidylglycerol liposomes, but it did not affect that of dipalmitoylphosphatidylcholine liposomes. These results indicate that mastoparan penetrated into membranes mainly containing acidic phospholipids and disrupted the membrane structure to increase the permeability. The action of the wasp venom mastoparan was compared with that of a bee venom melittin.

Increases in permeability of Escherichia coli outer membrane induced by polycations.

The action of polycations (such as polylysine and compound 48/80) on Escherichia coli was studied with use of Ca2+, K+ and TPP+ ion-selective electrodes. Rapid efflux of Ca2+ was observed when a polycation was added in cell suspension. The polycation treatment promoted a drug-inducing K+ release from the cytoplasmic membrane. TPP+ uptake was also increased by addition of a polycation. Without the polycation treatment, the uptake of TPP+ was largely suppressed due to a permeability barrier of the outer membrane. The results show that a polycation disrupted the permeability barrier of the outer membrane.

Compound 48/80-induced permeability change in liposomal membrane.

The action of compound 48/80 (a mixture of condensation products of p-methoxy-N-methylphenethylamine with formaldehyde) on liposomal membranes was studied by means of K+-loaded liposomes and a K+ ion-selective electrode. Prompt efflux of K+ was detected when 48/80 was added to the negatively charged liposome suspension, while the monomer of 48/80, p-methoxy-N-methylphenethylamine, did not release K+ from the same liposomes. The mechanism for the action of 48/80 is discussed in comparison with that of a polymyxin, well known as an antibiotic acting on bacterial membranes.

Opioid-mediated inhibition from the subnucleus caudalis of spinal trigeminal nucleus to the neurons in the subnucleus oralis.

The influence of enkephalin-containing neurons in the subnucleus caudalis of the spinal trigeminal nucleus (STN caudalis) on the subnucleus oralis of the STN (STN oralis) was examined using chloral hydrate-anesthetized rats. In the STN oralis, conditioning stimuli applied to the STN caudalis 10-50 ms preceding the test stimulus inhibited spikes produced by tooth pulp stimulation in type B interneuron, which was activated by orthodromic stimulation but not by thalamic stimulation, without affecting those of the relay neuron. When the type B interneurons were further classified into type B1 and type B2 neurons, which were characterized by the occurrence of the STN caudalis-induced inhibition with long and short latencies, respectively, microiontophoretically applied naloxone reduced the STN caudalis-induced inhibition of th orthodromic spikes of type B1 interneurons with little effects on type B2 interneuron. Furthermore, naloxone-reversible inhibition of tooth pulp-induced spikes of the type B1 interneurons were also observed during iontophoretic application of enkephalin. These results suggest that the type B1 interneurons in the STN oralis are inhibited by opioid peptides-containing neurons in the STN caudalis.

Lipid peroxidation as a possible cause of benzoyl peroxide toxicity in rabbit dental pulp--a microsomal lipid peroxidation in vitro.

The toxicity of composite resin on rabbit dental pulp was investigated biochemically. A microsomal fraction of rabbit dental pulp was incubated with each of the components of composite resins, and the formation of peroxide was determined by the thiobarbituric acid reaction. Benzoyl peroxide (BPO), the most widely used catalyst, was the most effective on peroxidation, but monomers were not. Cations such as Cu2+ or Fe2+ were required for acceleration of this reaction. Authentic polyunsaturated fatty acids and phospholipids were extensively converted into their peroxides by BPO, but amino acids and carbohydrates were not. Among the active oxygens, hydroxyl radicals were thought to be responsible for BPO-dependent peroxidation. The results presented in this paper indicate that the lipid portion of the cells may be attacked by hydroxyl radicals produced by BPO and copper or iron. Therefore, BPO is considered to be the major factor responsible for the toxicity of composite resins.

Replacement of myocardium with a Dacron prosthesis for complications of acute myocardial infarction.

From July 1983 to April 1986, four patients (three with ventricular septal perforations and one with left ventricular free-wall rupture) underwent replacement of the myocardium with a Dacron prosthesis for complications of acute myocardial infarction. There were three males and one female, ages ranging from 53 to 70 years (mean 63.3). Three of the four patients survived; the one with the ventricular septal perforation died of severe cardiac failure five days after operation. Replacement of the infarcted myocardium with a Dacron prosthesis seems to be an excellent operative technique for the treatment of complications of acute myocardial infarction when the left ventricular cavity is predicted to be small after resection of the myocardium.

Fatal necrotizing stomatitis due to Trichoderma longibrachiatum in a neutropenic patient with malignant lymphoma: a case report.

Primary invasive mold infection of the oral cavity is a rare but serious complication in immunocompromised hosts. We report a case of fatal Trichoderma longibrachiatum stomatitis in a 66-year-old female patient with malignant lymphoma. The infection rapidly disseminated from the oral mucosa to the lungs during neutropenia. Despite intensive antifungal therapy with amphotericin B and itraconazole, there was a fatal progression of the condition. While Trichoderma species have been recognized to be pathogenic in profoundly immunosuppressed hosts, this is the first report of the primary oral focus causing a fatal infection.

In vitro detection of equine arteritis virus from seminal plasma for identification of carrier stallions.

Equine arteritis virus (EAV) was readily isolated in RK-13 cell monolayers by plaque assay from seminal plasma of experimental carrier stallions when they contained high titers of virus regardless of the presence of non-viral cytotoxicity in the seminal plasma. The cytotoxicity interfered with virus isolation from seminal plasma which contained virus at titers less than 10 PFU/ml. However, it was possible to detect the virus in seminal plasma pretreated with PEG (#6000). EAV was consistently identified by RT-PCR from crude seminal plasma which contained virus at titers of more than 10(2.7) PFU/ml. In vitro detection of EAV by virus isolation supplemented with RT-PCR using seminal plasma was proved to be an effective alternative to the standard test mating as a diagnostic method for carrier stallions.

An epidemiological study of the influence of sweets intake and toothbrushing on dental caries among children in Japan.

The study was designed to determine the influence of confectionery and beverages intake and of toothbrushing on infant dental caries. The participants were 700 three year old Japanese children from an urban area near Tokyo. The prevalence of caries in those who frequently consumed confectionery and beverages was higher than the prevalence in those who did not take them. However, the prevalence in children with a habit of toothbrushing did not differ from that of those without the habit. This study shows that restricting consumption of confectionery and beverages may be effective in preventing dental caries; however, encouragement of toothbrushing may not be effective in limiting dental caries progression.

[Experience in the use of propiverine hydrochloride (P-4) for patients suffering from urinary frequency and/or incontinence].

The clinical effectiveness and safety of propiverine hydrochloride (P-4, 20 mg tablet) were studied on 29 patients with nervous pollakisuria, neurogenic bladder or unstable bladder, whose chief complaints were urinary frequency and/or urinary incontinence. The clinical efficacy was "good" or better in 62.1% and "fair" or better in 86.2%. Patients' impressions were "good" or better in 79.3%. There were a total of 4 cases (13.8%) of adverse reactions, namely, two cases of decreased urinary stream, one dry mouth, and one dizziness. These reactions disappeared rapidly after the completion or discontinuance of drug administration, and therefore, did not constitute significant safety problems. The clinical efficacy in the treatment of subjective symptoms was 74.1% for diurnal pollakisuria, 50.0% for nocturnal pollakisuria, 83.3% for urinary incontinence and 69.0% for urgent feeling of micturition. For objective symptoms, P-4 increased significantly the volume of maximum desire to void (MDV); however it did not increase significantly the residual urine volume. The results of this study suggest that propiverine hydrochloride is very useful for the treatment of urinary frequency and/or incontinence.

[Osteopontin mRNA expression in remodeling alveolar bone incident to tooth movement--visualized by in situ hybridization].

The purpose of this study was to investigate the osteopontin mRNA expression in the alveolar bone incident to the physiologic and experimental tooth movement. The upper jaws of female rats (7 weeks old) which were submitted to experimental molar tooth movement and control specimens were decalcified and sliced into paraffin sections. Osteopontin mRNA expression and tartrate-resistant acid phosphatase (TRACPase) activity were examined in the alveolar bone by use of in situ hybridization techniques and enzyme histochemistry, respectively. In the control specimens high levels of osteopontin mRNA expression was observed in the osteocytes and lining cells close to the osteoclasts which were detected by TRACPase staining in the distal areas of the tooth sockets. In the mesial tooth socket areas however, low levels of osteopontin mRNA expression was observed. In the experimental specimens high levels of osteopontin mRNA expression of both the osteoblasts and osteocytes was observed in the mesial areas of tooth sockets in response to the experimental tooth movement. These results indicated that osteopontin gene expression is related to the alveolar bone remodeling as far as the bone resorption incident to the physiologic tooth movement and that this expression level significantly increased in response to a certain mechanical stress incident to the experimental tooth movement.

[Study on mercury in dental calculus].

It has been reported that dental calculus contains trace elements of mercury besides lead, cadmium and zinc. The mercury is one of the hazardous metal elements from the environmental point of view. The purpose of this study was to clarify the mechanism of the accumulation of mercury in the dental calculus. The results were as follows: 1. The concentration of mercury was 1.6 ppm in the dental calculus collected from the subjects with no amalgam fillings. 2. The most of the mercury was found in the organic fraction of the dental calculus. 3. In the culture study of Bacterionema matruchotii in vitro, with the increase of Bacterionema matruchotii the uptake of mercury by the bacteria increased. And the maximum uptake of mercury was seen between 7 to 14 days of the culture period. 4. After 7 days of culture, the bacterial cells were destroyed into several fractions and the quantity of the mercury in the respective fractions was assayed. About 90% of mercury was found in the cell wall. From these results, it was suggested that the uptake of mercury by the bacteria was the cause of mercury accumulation in the dental calculus.