Comparison of tissue pressure and ablation time between the LeVeen and cool-tip needle methods

BACKGROUND: Radio frequency ablation (RFA) has been accepted clinically as a useful local treatment for hepatocellular carcinoma (HCC). However, intrahepatic recurrence after RFA has been reported which might be attributable to increase in intra-tumor pressure during RFA. To reduce the pressure and ablation time, we developed a novel method of RFA, a multi-step method in which a LeVeen needle, an expansion-type electrode, is incrementally and stepwise expanded. We compared the maximal pressure during ablation and the total ablation time among the multi-step method, single-step method (a standard single-step full expansion with a LeVeen needle), and the method with a cool-tip electrode. Finally, we performed a preliminary comparison of the ablation times for these methods in HCC cases. RESULTS: A block of pig liver sealed in a rigid plastic case was used as a model of an HCC tumor with a capsule. The multi-step method with the LeVeen electrode resulted in the lowest pressure as compared with the single-step or cool-tip methods. There was no significant difference in the ablation time between the multi-step and cool-tip ablation methods, although the single-step methods had longer ablation times than the other ablation procedures. In HCC cases, the multi-step method had a significantly shorter ablation time than the single-step or cool-tip methods. CONCLUSION: We demonstrated that the multi-step method was useful to reduce the ablation time and to suppress the increase in pressure. The multi-step method using a LeVeen needle may be a clinically applicable procedure for RFA

Dentin-pulp regeneration by 3D layered cell sheet

The dentin-pulp complex is a unique structure in teeth that contains both hard and soft tissues. Generally, deep caries and trauma cause damage to the dentin-pulp complex, and if left untreated, this damage will progress to irreversible pulpitis. The aim of this study was to fabricate a layered cell sheet composed of rat dental pulp (DP) cells and odontogenic differentiation of pulp (OD) cells and to investigate the ability to regenerate the dentin-pulp complex in a scaffold tooth. We fabricated two single cell sheets composed of DP cells (DP cell sheet) or OD cells (OD cell sheet) and a layered cell sheet made by layering both cells. The characteristics of the fabricated cell sheets were analyzed using light microscopy, scanning electron microscopy (SEM), hematoxylin-eosin (HE) staining, and immunohistochemistry (IHC). Furthermore, the cell sheets were transplanted into the subrenal capsule of immunocompromised mice for 8 weeks. Following this, the regenerative capacity to form dentin-like tissue was evaluated using micro-computed tomography (Micro-CT), HE staining, and IHC. The findings of SEM and IHC confirmed that layered cell sheets fabricated by stacking OD cells and DP cells maintained their cytological characteristics. Micro-CT of layered cell sheet transplants revealed a mineralized capping of the access cavity in the crown area, similar to that of natural dentin. In contrast, the OD cell sheet group demonstrated the formation of irregular fragments of mineralized tissue in the pulp cavity, and the DP cell sheet did not develop any hard tissue. Moreover, bone volume/tissue volume (BV/TV) showed a significant increase in hard tissue formation in the layered cell sheet group compared to that in the single cell sheet group (p<0.05). HE staining also showed a combination of soft and hard tissue formation in the layered cell sheet group. Furthermore, IHC confirmed that the dentin-like tissue generated from the layered cell sheet expressed characteristic markers of dentin but not bone equivalent to that of a natural tooth. In conclusion, this study demonstrates the feasibility of regenerating dentin-pulp complex using a bioengineered tissue designed to simulate the anatomical structure

Relation between self-schema and knowledge of the hometown : A case of Okinawa <Article>

本研究は,沖縄県大学生を対象に,自己スキーマと特定の文化に最も多くみられる性格特性(モーダル・パーソナリティ)の関連について川平(1988)の性格特性認知課題を用いて検討した。性格特性認知課題では,予備調査を基に選定した沖縄県民と他県民のモーダル・パーソナリティが自己の性格にあてはまるか(自己判断課題),沖縄県民と他県民のどちらに特徴的か(モーダル・パーソナリティ判断課題)の判断を課した。また,モーダル・パーソナリティ判断課題の前には,自己の性格が日本人的か否かのフィードバックあるいは沖縄の自然風景写真を提示することによって,沖縄県民意識の操作を行った。実験の結果,自己判断課題において,自己記述的と判断された沖縄県民と他県民のモーダル・パーソナリティ数に出身県による差はみられなかった。しかし,沖縄の自然風景写真を提示後にモーダル・パーソナリティ判断課題を課した場合,沖縄県出身者は沖縄県民のモーダル・パーソナリティを正確に識別できることが明らかになった。以上の結果は,現在の沖縄県民においては自己スキーマとモーダル・パーソナリティの関連が希薄化していることを示唆している

A Trial of Home Oxygen for Acute Asthma Attacks for the Prevention of Asthmatic Death

Physicians are very much concerned that death from asthma has not significantly declined despite modern treatment. Since most asthma deaths take place at home it is mandatory to keep in mind that adequate management should be commenced as early as possible at home when a severe asthmatic attack develops especially in high-risk patients. For preventive care, the main objective should be to avoid severe hypoxemia with resultant cardiac arrest that may occur during severe asthmatic attacks at home and during transportation. A total of 97 patients were studied with near-fatal asthmatic attacks requiring mechanical ventilation at least once during the period from January 1979 to November 1993, these patients were seen at Okinawa Chubu Hospital and survived without significant morbidity. They were considered at high risk for recurrence of life-threatening asthmatic attacks and death and were therefore persuaded to undergo a trial of immediate self-oxygenation at home and during transportation to an emergency department whenever a severe attack developed. Only 61 patients agreed to our request. Among those who agreed to install home oxygen, 24 subsequently developed severe attacks requiring mechanical ventilation outside hospital during following 15 years. Sixteen of them immediately started oxygenation at home in addition to the anti-asthma medication, continuing the process all the way to emergency center; all survived. Eight Patients did not actually take their home oxygen and four of them died p<0.05). Among the 36 patients who declined home oxygen trial, 13 experienced recurrences of severe asthmatic attacks outside the hospital ; nine of them died. Long-term follow up disclosed that 8.1 percent of those receiving home oxygen offered to them (n=61) died from an asthmatic attack. On the other hand, 30.5 percent of those who refused to have home oxygen (n=36) died within a 15 years period (p<0.05)