Electrochemical bacteriocidal action based on electron transfer of salivary bacteria.

Based upon the observation that most oral bacteria are negatively charged, we attempted to restrain the development of oral bacteria in saliva by applying a constant electric potential to an electrode. The development of salivary bacteria was clearly restrained by applying 0.74V electric current for 30 min. This restraint was in inverse proportion to the concentration of the suspension of salivary bacteria. The authors hypothesize that the electrochemical restraining was based on electron transfer between the salivary bacteria and the electrode.

[Spontaneous cleft palate in CF#1/Ohu mice].

We found a spontaneous cleft palate in a mouse of CF#1/Ohu (Ohu University, Japan). Further, the frequency of the spontaneous cleft palate in strains of CF#1/Jms (Institute of Medical Science, University of Tokyo, Japan) and CF#1/Jah (National Institute of Animal Health, Japan) were about 3%, respectively. The frequency and the types of spontaneous cleft palate in CF#1 were clearly different from those in A/J and CL/Fr strains which were used as model animals of lip and cleft palate. We think that CF#1 is the new animal models to analyze a cleft palate genetically and biochemically.

[Clinical evaluation of cefuroxime axetil in acute dental infections. Double blind comparative study vs. cefaclor].

To evaluate objectively clinical efficacy, safety and usefulness of cefuroxime axetil (CXM-AX) in acute dental infections (periodontitis, pericoronitis and gnathitis), we carried out a comparison study using cefaclor (CCL) as the control. Both drugs were orally given after meals in a dose level of 250 mg (potency) t.i.d. for 3-7 days. 1. Clinical efficacy rates in all the treated cases were 81.6% (102/125) in the CXM-AX group and 82.5% (104/126) in the CCL group according to the assessment by physicians in charge, and 89.6% (112/125) and 83.3% (105/126), respectively, according to the assessment based on scores. No significant difference was found between the 2 treatment groups. In clinical efficacy (assessment by score) classified by background factors, efficacy rate in the CXM-AX group (90.6%, 58/64) was significantly higher (P less than 0.05) than that in the CCL group (75.0%, 48/64) in cases receiving no surgical treatment on the first day of drug administration. Other background factors than the above (no surgical treatment) factor or scores on the first day of drug administration, however, did not appear to influence clinical efficacies of 2 treatment groups. 2. As for the bacteriological response in all the treated cases, elimination rate in the CXM-AX group was 73.7% (28/38) and that in the CCL group, 78.3% (36/46), without significant difference between the 2 groups. 3. Regarding the safety, no significant difference was found between the 2 treatment groups. Adverse reactions were observed in 1 out of 128 cases (0.8%) in the CXM-AX group and 6 out of 132 cases (4.5%) in the CCL group. Abnormal laboratory test values were noted in 8 out of 86 cases (9.3%) in the CXM-AX group and 5 out of 91 cases (5.5%) in the CCL group. None of these differences between 2 treatment groups was statistically significant. 4. Usefulness rates in all the treated cases were 81.6% (102/125) in the CXM-AX group and 81.7% (103/126) in the CCL group, thus significant difference was observed between the 2 groups. From the above results, CXM-AX is considered to be a useful drug like CCL in the treatment of acute dental infections.

[Epithelial dysplasia and invasive carcinoma of oral cavity showing punctation and atypical vessels].

We have experienced epithelial dysplasia and invasive carcinoma of oral cavity, showing punctation and mosaic like atypical vessels confirmed by usual photographing. Case 1: 42-year-old man. After resection of tongue leukoplakia, the punctation appeared in the distal region of resected wound. Pathological findings were epithelial dysplasia, and expansion of capillaries in the stromal papillae were close to the surface. Case 2: 55-year-old woman. Punctation and mosaic like atypical vessels were recognized in the buccal mucosa, extending from the gingival carcinoma. Pathological findings were epithelial dysplasia and carcinoma in situ in punctation, and early invasive carcinoma in mosaic. There were irregularly expanded capillaries in the stromal papillae being close to the surface at both mosaic and punctation area. Although punctation, atypical vessels and mosaic are the colposcopic findings of uterine cervical cancer, these findings may become diagnostic point of early oral cancer.

[A case of greater auricular nerve autologous nerve grafting for inferior alveolar nerve injury by mandibular fracture].

The results of peripheral nerve repair have been greatly improved in the last few years following the introduction of micro-surgery and increased application of free autologous nerve transplants. In the field of oral surgery, a rich experience has been made in plastic and reconstructive repair. The inferior alveolar nerve is endangered by a series of mandibular fractures, with fracture lines running along the nerve canal. For plastic repair of the inferior alveolar nerve, we interpose an autologous transplant from the greater auricular nerve.

Experimental tongue carcinoma of rats induced by oral administration of 4-nitroquinoline 1-oxide (4NQO) in drinking water.

Oral administration of 0.001% 4NQO in drinking water resulted in a high incidence of tongue carcinoma in rats. In other major organs, tumor induction was rarely observed. The most frequent site of tongue carcinoma was the dorsum. No metastases were found. Changes observed included carcinoma in situ and invasive carcinoma. Carcinoma in situ showed erosion, leukoplakia, and a gross papillary appearance. Histologically, most carcinomas in situ showed full-thickness alteration of epithelium. Some carcinomas in situ in papillary lesions showed slightly less than full-thickness alteration of epithelium, exhibiting downward, well-differentiated growth. Invasive carcinomas were either endophytic or exophytic. Histologic grading of invasive carcinoma varied from highly to poorly differentiated. The method described offers a new experimental animal model of tongue carcinoma.

Spontaneous calcified tongue lesions in DBA mice.

Large numbers of spontaneously occurring polypoid or slightly elevated lesions were observed in the tongue, mainly the dorsum linguae near the margo linguae, of DBA mice. Histologically the lesion consisted of granulation tissue with focal calcification, and involved superficially the tongue muscle. Often the calcareous deposits were encircled by multinuclear giant cells. The frequency of the calcified tongue lesion was high in lines of DBA/2 (DBA/2NCrj, DBA/2NJcl and DBA/2J), and DBA/1 (DBA/1Jcl and DBA/1J); the SM/J, BALB/c, C57BL/6 and C3H/He strains did not have the lesion. Among hybrid mice, CDF1, a hybrid of DBA/2 and BALB/c, a few had the lesions but no BDF1 mice, a hybrid of DBA/2 and C57BL/6, had any. The frequency was high in the hybrids of DBA/1 and SM/J. These results seem to indicate that the occurrence of the tongue calcified lesions was controlled by polygene.

Repression of sporulation in Bacillus subtilis by L-malate.

L-Malate repressed sporulation in the wild-type strain of Bacillus subtilis. When 75 mM L-malate was added to the growth medium at the time of inoculation, the appearance of heat-resistant spores was delayed 6 to 8 h. The synthesis of extracellular serine protease, alkaline phosphatase, glucose dehydrogenase, and dipicolinic acid was similarly delayed. Sporulation was not repressed when malate was added to the culture at t4 or later. A mutant was selected for ability to sporulate in the presence of malate. This strain could also sporulate in the presence of glucose. The malate-resistant mutant grew poorly with malate as sole carbon source, although it possessed an intact citric acid cycle, and it showed increased levels of malic enzyme. This indicates a defect in the metabolism of malate in the mutant. A mutant lacking malate dehydrogenase activity was also able to sporulate in the presence of malate. A model for the regulation of sporulation by malate is presented and discussed. Citric acid cycle intermediates other than malate did not affect sporulation. In contrast to previous results, sporulation of certain citric acid cycle mutants could be greatly increased or completely restored by the addition of intermediates after the enzymatic block. The results indicate that the failure of citric acid cycle mutants to sporulate can be adequately explained by lack of energy and lack of glutamate.

Regulation of the dicarboxylic acid part of the citric acid cycle in Bacillus subtilis.

The regulation of alpha-ketogluterate dehydrogenase, succinate dehydrogenase, fumarase, malate dehydrogenase, and malic enzyme has been studied in Bacillus subitilis. The levels of these enzymes increase rapidly during late exponential phase in a complex medium and are maximal 1 to 2 h after the onset of sporulation. Regulation of enzyme synthesis has been studied in the wild type and different citric acid cycle mutants by adding various metabolites to the growth medium. Alpha-ketoglutarate dehydrogenase is induced by glutamate or alpha-ketoglutarate; succinate dehydrogenase is repressed by malate; and fumarase and malic enzyme are induced by fumarate and malate, respectively. The addition of glucose leads to repression of the citric acid cycle enzymes whereas the level of malic enzyme is unaffected. Studies on the control of enzyme activities in vitro have shown that alpha-ketoglutarate dehydrogenase and succinate dehydrogenase are inhibited by oxalacetate. Enzyme activities are also influenced by the energy level, expressed as the energy charge of the adenylate pool. Isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase, succinate dehydrogenase, and malic enzyme are inhibited at high energy charge values, whereas malate dehydrogenase is inhibited at low energy charge. A survey of the regulation of the citric acid cycle in B.subtilis, based on the present work and previously reported results, is presented and discussed.

Regulation of aconitase synthesis in Bacillus subtilis: induction, feedback repression, and catabolite repression.

The synthesis of aconitase in Bacillus subtilis wild-type and different citric acid cycle mutants has been studied and the influence of various growth conditions examined. Aconitase is induced by citrate and precursors of citrate and repressed by glutamate. Induction and repression counteract each other, and at equimolar concentrations of citrate and glutamate, aconitase synthesis is unaffected. Induction by citrate can partly overcome catabolite repression of aconitase. Isocitrate dehydrogenase show endogenous induction of aconitase due to citrate accumulation. Leaky mutants defective in citrate synthase and aconitase cannot be induced by citrate, which indicates that they carry a regulatory mutation. The complex regulation of aconitase is discussed with reference to the participation of this enzyme in glutamate biosynthesis and energy metabolism.

Genetic and biochemical characterization of mutants of Bacillus subtilis defective in succinate dehydrogenase.

Eleven succinate-accumulating mutants of Bacillus subtilis have been mapped by transformation and transduction crosses and characterized with respect to activities of citric acid cycle enzymes. These mutants could be divided into three genetic groups. Nine of the mutants were found to map between argA and leu in the citF locus. A second group was located between lys-1 and trpC2 and the third group could not be located on the B. subtilis chromosome in extensive transduction crosses. All of the citF mutants lack detectable succinate dehydrogenase activity, whereas both of the other groups show a reduced level of this enzyme. In addition, most of the mutants in the citF locus lack cytochrome a, whereas the level of this cytochrome is normal in the other two groups. A procedure has been devised for the solubilization of the succinate dehydrogenase from the membrane of B. subtilis with the non-ionic detergent Brij 58. Some properties of the soluble and bound forms of succinate dehydrogenase are described.