Prevention of Root Caries Using Oxalic Acid

Certain dentin hypersensitivity treatment materials include oxalic acid to coat dentin surfaces with minerals, while certain organic acids possess a remineralization effect. Herein, an organic acid that inhibits the demineralization and coating of root surfaces was evaluated. Specimens were produced using five non-carious extracted bovines. Four different acids were used: oxalic acid (OA), malonic acid (MA), polyacrylic acid (PA), and succinic acid (SA). Each acid was applied to the root surface and washed using distilled water or a remineralization solution, and the surface was observed using scanning electron microscopy (SEM). All the surfaces of each specimen, barring the polished surface, were covered with wax and immersed in an automatic pH cycling system for two weeks. Dentin demineralization was analyzed using transverse microradiography (TMR) before and after pH cycling. SEM analysis demonstrated that the three acid groups demineralized the dentin surface, whereas the OA group generated crystals covering the dentin surface, even in a distilled water environment. TMR analysis revealed that the OA groups showed significantly lower integrated mineral loss compared with the other groups, even in the distilled water environment. The results suggest that OA generates insoluble calcium oxalate crystals on the dentin and suppresses demineralization even under low saliva conditions.

Size- and Morphology-Controlled Preparation of Surface-Modified Water-Dispersible Fullerene Nanoparticles for Bioapplications

In this study, we investigated water-dispersible surface modification for size- and shape-controlled fullerene nanoparticles (C₆₀P) based on a condensation reaction with di-amino alkane. This modification provided for water dispersibility of C₆₀P and the capability for secondary modification as well. The resultant C₆₀P particles have several useful physical properties: water-dispersibility for ease of injection; fluorescence for detection and quantification; and a characteristic morphology to assist identification. These properties will widely extend the applications of these particles, especially into the biological fields of bioimaging and drug delivery.

Movement-related cortical magnetic fields associated with self-paced tongue protrusion in humans

Sophisticated tongue movements are coordinated finely via cortical control. We elucidated the cortical processes associated with voluntary tongue movement. Movement-related cortical fields were investigated during self-paced repetitive tongue protrusion. Surface tongue electromyograms were recorded to determine movement onset. To identify the location of the primary somatosensory cortex (S1), tongue somatosensory evoked fields were measured. The readiness fields (RFs) over both hemispheres began prior to movement onset and culminated in the motor fields (MFs) around movement onset. These signals were followed by transient movement evoked fields (MEFs) after movement onset. The MF and MEF peak latencies and magnitudes were not different between the hemispheres. The MF current sources were located in the precentral gyrus, suggesting they were located in the primary motor cortex (M1); this was contrary to the MEF sources, which were located in S1. We conclude that the RFs and MFs mainly reflect the cortical processes for the preparation and execution of tongue movement in the bilateral M1, without hemispheric dominance. Moreover, the MEFs may represent proprioceptive feedback from the tongue to bilateral S1. Such cortical processing related to the efferent and afferent information may aid in the coordination of sophisticated tongue movements.

Left thoracoabdominal approach for adenocarcinoma of the esophagogastric junction

BACKGROUND/AIMS

To evaluate usefulness of esophagogastrectomy via left thoracoabdominal (LT) approach for adenocarcinoma of the esophagogastric junction (AEG), the results of surgery stratified by Siewert's classification, were analyzed retrospectively.

METHODOLOGY

The tumor diameter, distance of the proximal tumor border from the esophagogastric junction, and length of the esophagus in the resected specimens of consecutive 171 AEG patients were measured. The surgical approach was classified as total esophagectomy (TE), esophagogastrectomy via LT, or transhiatal/abdominal (HA) approach.

RESULTS

Sixteen patients underwent TE, 71 had LT, and 84 had HA. Overall survival of the TE and LT groups was significantly lower than that of the HA group. The difference was seen between LT and HA for type II T3 tumors, but the tumor diameter in LT was significantly larger than that in HA. The approach could not be determined by Siewert's classification, but by distance of proximal tumor border from the junction. The tumors with distance over 5cm might be indicated for the TE approach; 5-3cm, the LT; within 3cm, the HA. The percentage of patients in whom the LT approach is indicated might be only 19%.

CONCLUSION

Left thoracoabdominal esophagogastrectomy may be valid for some AEG.

Apoptosis Inhibitor Expressed by Macrophages Tempers Autoimmune Colitis and the Risk of Colitis-Based Carcinogenesis in TCRα−/− Mice

BACKGROUND

Crohn's disease and ulcerative colitis (UC) are the two main entities involved in human inflammatory bowel disease (IBD). However, their precise etiologies remain unclear. To study the development of mucosal inflammation, and chronic inflammation-based dysplasia and carcinoma formation, we examined possible roles of the apoptosis inhibitor expressed by macrophages (AIM) in an experimental IBD model.

METHODS

In this study, we used T cell receptor alpha deficient (TCRalpha(-/-)) mice, a known UC-like colitis model. We generated TCRalpha(-/-) x AIM(-/-) double knockout mice by crossbreeding TCRalpha(-/-) with AIM(-/-) mice. At 24 weeks of age, mice were killed to obtain colon tissues for pathological examinations. TCRalpha(-/-) x AIM(+/-) mice, heterozygous littermates of TCRalpha(-/-) x AIM(-/-) mice, were used as controls.

RESULTS

Severe colitis was observed in TCRalpha(-/-) x AIM(-/-) mice, when compared with TCRalpha(-/-) x AIM(+/-) mice. Dysplasia was detected in TCRalpha(-/-) x AIM(-/-) mice, but not in TCRalpha(-/-) x AIM(+/-) mice. Adenocarcinoma formation was observed from dysplasia only in TCRalpha(-/-) x AIM(-/-) mice.

CONCLUSION

Not only a high incidence of severe colitis but also dysplasia and adenocarcinoma formation were observed in TCRalpha(-/-) x AIM(-/-) mice only. AIM have some regulatory roles in inflammation and progression of dysplasia to carcinoma in TCRalpha(-/-) mice.

Detection of bone marrow micrometastasis in gastric cancer patients by immunomagnetic separation

BACKGROUND

Micrometastasis to the bone marrow can predict widespread disease and a poor prognosis of cancer patients after surgery. The purpose of this study was to evaluate the clinical significance of detecting micrometastasis in the bone marrow of gastric cancer patients.

METHODS

Bone marrow and peripheral blood samples were obtained from 53 gastric cancer patients at the time of surgery. These samples were enriched by immunomagnetic separation and immunostained with an anti-cytokeratin antibody. Expression of vascular endothelial growth factor and erbB-2/HER2 was examined in the primary tumors.

RESULTS

Cytokeratin-positive cancer cells were observed in the bone marrow of 16 (30%) of 53 patients. Among them, two patients also had cancer cells in the peripheral blood. The presence of bone marrow micrometastasis was correlated with the depth of invasion and lymph node metastasis but was not associated with peritoneal dissemination. Detection of bone marrow micrometastasis was not correlated with vascular endothelial growth factor or HER2 expression in the primary tumors. Four patients with micrometastasis had recurrence in the liver or lungs, but this did not occur in patients without micrometastasis.

CONCLUSIONS

Detection of cancer cells in the bone marrow might be an indicator of postoperative hematogenous metastasis in gastric cancer patients.

Pilot study of S-1 in patients with disseminated gastric cancer

The prognosis for patients with advanced gastric cancer remains poor. Peritoneal metastasis is the most frequent cause of death in patients with gastric cancer, but the most appropriate treatment for patients with disseminated gastric cancer remains uncertain. S-1 is a newly developed oral fluoropyrimidine derivative with unusually high activity against several tumor types. The aim of this study was to evaluate the feasibility and efficacy of S-1 for the treatment of patients with disseminated gastric cancer. A total of 31 patients with primary or recurrent gastric cancer with peritoneal dissemination were entered into this study. One course of this single-drug therapy consisted of S-1 (80-120 mg) twice daily for 28 days, followed by a 2-week period of no treatment. These treatments were repeated until disease progression or patient refusal. With a median follow-up period in survivors of 293 days, the median survival time was 357 days. Toxicities were mild and no patient withdrew from treatment before disease progression. Grade 3 hematotoxicity was observed in only one patient. S-1 showed promising activity against gastric cancer with peritoneal dissemination and acceptable toxicity. Further evaluation of S-1 treatment is warranted in this disease.

Early anchoring collagen fibers at the bone-tendon interface are conducted by woven bone formation: light microscope and scanning electron microscope observation using a canine model

To clarify the early process of recovery at the bone-tendon interface, we used light microscopy and SEM to examine the process of anchoring of collagen fibers to bone in a canine model. At two weeks, tendon, scar tissue, woven bone and lamellar bone were present at the insertion site. SEM revealed anchoring of collagen fibril bundles of the scar to the woven bone. By 4 weeks, the number of anchoring fibers had increased and a parallel arrangement of fibers was observed. SEM demonstrated deep penetration of fibers into the woven bone layer. In addition, the fibers were observed to project into and intermingle with the scar tissue. By 6 weeks, the anchoring fibers had developed fully and were distributed densely over the interface. SEM also revealed that the collagen fibril bundles in the scar tissue had connected with the collagen fibrils of the woven bone by way of the anchoring bundles. The woven bone was identifiable throughout the early stages of recovery as the interface between soft tissue and hard tissue. Throughout all experimental periods, no staining was observed at the interface of the tendon and bone by Saffranin-O. The formation of woven bone was important during early recovery of the tendon-bone interface prior to the completion of fibrocartilage-mediated insertion.

Fibrous connection to bone after immediate repair of the canine infraspinatus: the most effective bony surface for tendon attachment

The purpose of this histologic study was to identify the most effective bony surface for fibrous connection to bone after immediate repair of the canine infraspinatus. Light microscopic views were used to evaluate collagen fiber development. The left infraspinatus tendon of 15 dogs was transected and repaired to 3 different bone surfaces: a tendon end adjacent to the tendon insertion (group 1, n = 5), a calcified fibrocartilage layer (group 2, n = 5), and a cancellous surface (group 3, n = 5). Tendon repair to distal tendon ends restored the 4-layered enthesis in the healing period, whereas tendon repair to the calcified fibrocartilage layer considerably delayed fiber development into bone. Fiber connection to cancellous surface developed according to the remodeling of trabecular bone. Secure fiber connection into the thickened trabecular bone developed by 16 postoperative weeks. On the basis of these results, in clinical settings, ruptured tendon ends should be attached to the remaining distal tendon end or to a cancellous surface; they should not be attached to a calcified fibrocartilage layer.

[The role of endoscopic ultrasonography for gastric cancer in the cardiac area]

In order to select the most appropriate treatment for gastric cancer in the cardiac area, precise staging by determining the depth of cancer invasion, and esophageal invasion, and lymph node metastases is important. In this paper, diagnosis of these factors using endoscopic ultrasonography (EUS) and its accuracy are discussed. In 121 cases of gastric cancer in the cardiac area, EUS was performed and the findings compared with the pathological diagnosis. The depth of cancer invasion was accurately determined in 60% of mucosal cancer cases, 83% of cancer invading the submucosa, 50% of cancer invading the muscularis propria or the subserosa, 86% of cancer invading the serosa, 45% of cancer invading other organs, and overall accuracy was 77%. In cases of esophageal invasion sensitivity was 98%, specificity 93%, and overall accuracy 94%. In cases of lymph node metastasis specificity was 78%: 86% for N1 and 72% for N2. EUS therefore has an important role in diagnosis and selection of treatment.

Citrate promotes attachment of Prevotella nigrescens (intermedia) ATCC 25261 to hydroxyapatite

Large quantities of Prevotella nigrescens (intermedia) ATCC 25261 (P. nigrescens) cells adhere to hydroxyapatite (HA) treated with citrate, but do not adhere experimental pellicle prepared from human whole saliva. To determine the nature of the citrate responsible for promoting P. nigrescens cell adhesion, the duration and frequency of citrate treatment of HA and the inhibitory effect of other carboxylates were tested. The citrate rapidly adhered to HA beads in less than 15 min. With a lower concentration (0.4 mM) of citrate, four treatments of HA were required to promote the maximum adherence to P. nigrescens cells. Citrate-enhanced P. nigrescens cell adherence to HA beads was also inhibited in the presence of cis-aconitate, oxaloacetate and oxalsuccinate. It was also found that P. nigrescens cells heated to 65 degrees C or higher for 5 min could no longer become attached to citrate-treated HA. These data suggest that citrate is one of the essential factors responsible for P. nigrescens cell attachment to apatitic surfaces, and that P. nigrescens' adhesion to citrate is extremely heat-sensitive.

[Oozing type left ventricular rupture: report of three cases]

Two cases of postinfarction oozing type left ventricular rupture and a case of oozing type left ventricular rupture due to catheter perforation for left ventriculography are reported. The technique used to repair the rupture is fibrin glue-oxycellulose fixation method. The post operative course of three cases were uneventful. But left ventricular aneurysm remained in two cases.

[A left subclavian arterial aneurysm caused by fibromuscular dysplasia: a case report]

A 70-year-old man complained left supraclavicular pulsatile tumor. Angiography and CT revealed the left subclavian arterial aneurysm that was just behind the clavicle. The aneurysm was resected through a cross-clavicle incision and an 8 mm Hemashield graft was implanted. The pathological study showed change of fibromuscular dysplasia. The post-operative course was uneventful.

Adsorption of salivary proteins to the surface of oral streptococcal cells

Oral tissues, especially tooth surfaces, are covered with a layer of salivary proteins. Oral bacterial cells that adsorb to salivary components accumulated on the tooth surface are, as a rule, covered with the same components, especially proteins. Thus, it is possible that the salivary proteins covering the bacterial cells are related to the adhesion of bacteria to oral tissues. The aim of this study was to clarify the mechanisms of adsorption of salivary proteins to the surface of Streptococcus sanguis, S. mitis and S. salivarius using an adsorption assay with salivary proteins labeled with tritiated formaldehyde. The results showed that salivary proteins adsorbed more to S. salivarius than to S. mitis, and least to S. sanguis. It was evident that hydrophobic bonding was involved in the adsorption of salivary proteins to the bacterial cells tested. The amount of salivary proteins adsorbed to S. mitis and S. salivarius was decreased by the presence of phosphate, that to S. sanguis was increased by the presence of a divalent cation such as Ca2+, and that to all bacteria tested was inhibited in different ways by the presence of sugars. The amount of salivary proteins adsorbed to S. sanguis and S. salivarius was reduced effectively by pretreatment of the cells with trypsin, chymotrypsin and papain. In the case of S. mitis, the amount of adsorbed salivary proteins was decreased by pretreatment of the cells with chymotrypsin only, and was increased by pretreatment with lipase. These results indicate that there are different mechanisms of adsorption of salivary protein to the cell surfaces of oral streptococci.