Fracture mechanisms of retrieved titanium screw thread in dental implant

Titanium and its alloy are increasingly attracting attention for use as biomaterials. However, delayed fracture of titanium dental implants has been reported, and factors affecting the acceleration of corrosion and fatigue have to be determined. The fractured surface of a retrieved titanium screw and metallurgical structures of a dental implant system were analyzed. The outer surface of the retrieved screw had a structure different from that of the as-received screw. It was confirmed that a shear crack initiated at the root of the thread and propagated into the inner section of the screw. Gas chromatography revealed that the retrieved screw had absorbed a higher amount of hydrogen than the as-received sample. The grain structure of a titanium screw, immersed in a solution known to induce hydrogen absorption, showed features similar to those of the retrieved screw. It was concluded that titanium in a biological environment absorbs hydrogen and this may be the reason for delayed fracture of a titanium implant.     

Calprotectin (S100A8/S100A9), an inflammatory protein complex from neutrophils with a broad apoptosis-inducing activity

Calprotectin, a complex of two calcium-binding proteins that belong to the S100 protein family, is abundant in the cytosolic fraction of neutrophils. A high level of calprotectin reportedly exists in extracellular fluid during various inflammatory conditions, such as rheumatoid arthritis, cystic fibrosis and abscesses. However, the exact biological role(s) of the factor is now under investigation. We recently observed that neutrophils contain a factor that shows growth-inhibitory and apoptosis-inducing activities against various cell types including tumor cells and normal fibroblasts, and we identified that factor as calprotectin. The findings suggest that calprotectin exerts a regulatory activity in inflammatory processes through its effect on the survival or growth states of cells participating in the inflammatory reaction. It is also possible that calprotectin, at a high concentration, might have a deleterious effect on fibroblasts and influence the recovery of inflammatory tissue. Therefore, the protein factor may be a new drug target to control inflammatory reactions. We found that a few of the Amaryllidaceae alkaloids effectively inhibited the growth-inhibitory and apoptosis-inducing activities of calprotectin. In this article, we focus on the biological functions of calprotectin in extracellular fluids, focusing on its apoptosis-inducing activity.     

Comparison of barium swallow,CT and thallium-201 SPECT in evaluating responses of patients with esophageal squamous cell carcinoma to preoperative chemoradiotherapy

The aims of this study were to compare the results of thallium-201 (Tl-201) SPECT, barium swallow and CT in the assessment of the effect of preoperative chemoradiotherapy. This study consisted of 28 patients with advanced esophageal squamous cell carcinoma (AESCC) who underwent the three imaging modalities before and after preoperative chemoradiotherapy. The results were quantified using the bidimensional method for barium swallow and contrast-enhanced CT and the tumor-to-lung ratio for SPECT. The percent decrease in these quantitative values after therapy was defined as %Dba, %Dct and %Dtl respectively. The histological effect of the chemoradiotherapy was determined from the resected surgical specimen of the esophagus: grade 0, 100% viable tumor cells; grade 1a, 99-67%; grade 1b, 66-34%; grade 2, 33-1%; grade 3, no viable cells. A statistically significant difference of %Dtl between the subgroups of each grade was evident (p = 0.0433), whereas no significant differences were evident for %Dba (p = 0.1778) or %Dct (p = 0.7377). However, the overlap of %Dtl between these groups was marked. Although thallium-201 SPECT cannot be used to evaluate the therapeutic effect with acceptable accuracy, SPECT may be of additional value to barium swallow and CT in assessing the response of AESCC to preoperative chemoradiotherapy.     

Successful treatment of postoperative multiple hepatic recurrence with hepatic arterial infusion of cisplatin and degrable starch microspheres

A 38-year-old man had multiple recurrence of hepatocellular carcinoma (HCC) with portal vein thrombosis after hepatectomy and postoperative transcatheter arterial chemotherapy with 5-fluorouracil (5-FU). He was treated by trans hepatic arterial embolization (TAE) with 100 mg of cisplatin (CDDP) and degrable starch microspheres (DSM). After 3 courses were administered, the recurrent lesions almost disappeared on CT, and the postoperative rise in PIVKA-II level and AFP level normalized. There were no side effects except slight fever and general fatigue. We recognized a partial response, and the patient is still alive 14 months after hepatectomy. This case suggests that TAE with CDDP and DSM might be useful for prolonging the survival of advanced HCC patients.     

Transience in polyion complexation between nicotinamide-modified dextran and carboxymethyl dextran during enzymatic degradation of dextran

A self-regulated degradation system using polyion complexation through oxidation reaction from degradation products was preliminarily studied. 1,4-Dihydronicotinamide-modified dextran (NAH-Dex) with different molecular weights was prepared, and NAH moiety in NAH-Dex was oxidized by H2O2 to the dehydrated form (NA+-Dex). The dependence of stoichiometry, concentration, and molecular weight on polyion complexation with carboxymethyl dextran (CMD) were examined. NA+-Dex with a molecular weight above 40000 formed an insoluble complex with CMD, and the complexation was found to proceed stoichiometrically. The extent of polyion complexation was dependent on the concentration of NA+-Dex and CMD, whereas the time to reach complexation was dependent on H2O2 concentration. When H2O2 and dextranase were added to the solution containing NAH-Dex, CMD, and dextran, transmittance dropped and then increased again. From these results, the addition of dextran into the system of H2O2, NAH-Dex, CMD, and dextranase can regulate formation and dissociation of the polyion complex between NA+-Dex and CMD. The antagonistical inhibition of the degradation of the polyion complex is a key parameter of the self-regulated degradation system.     

Hand-assisted laparoscopic splenectomy for a huge splenic cyst: operative technique and case report

We report the case of a huge splenic cyst that was successfully treated by hand-assisted laparoscopic splenectomy. A 17-year-old girl with a chief complaint of left-sided abdominal pain was admitted to our department for investigation of a splenic tumor. Ultrasonography, computed tomography, and magnetic resonance imaging revealed a huge cystic lesion in the spleen measuring approximately 10 cm in diameter. Hand-assisted laparoscopic splenectomy was safely performed to diagnose and treat the splenic tumor. The histologic diagnosis was an epithelial cyst of the spleen with no atypical cells in the cyst wall. Hand-assisted laparoscopic splenectomy may be a good method of managing a huge splenic cyst that becomes symptomatic and potentially life-threatening through enlargement, rupture, and secondary infection.     

Clinical efficacy of olanzapine]

The treatment of schizophrenic patients who fail adequate trials of typical neuroleptics is a major challenge. For these patients, the availability of atypical antipsychotics is a useful therapeutic advance. Olanzapine shows a superior and broader spectrum of efficacy in the treatment of schizophrenia, particularly its negative symptoms, with a substantially more favorable safety profile than conventional antipsychotic agents (e.g., haloperidol). However, little information on the clinical effects of olanzapine is available in Japan. This article provides information on the efficacy of olanzapine for various symptoms of schizophrenic patients and drug safety. Olanzapine is significantly superior to haloperidol in positive, negative, and depressive symptoms of patients, and for tardive dyskinesia and extrapyramidal symptoms. Significantly greater improvement in avolition-apathy is achieved with olanzapine as compared to risperidone. These advantages are related to high affinity at the 5-HT2 binding site, no association with an alteration in dopamine A9 firing rates, and lower D2 striatal receptor blockade of olanzapine. Treatment with 10 mg/day olanzapine is more appropriate for positive symptoms, and 12.5-17.5 mg/day olanzapine is more effective for negative symptoms. Patients will need help adapting to a new level of functioning after a successful switch to olanzapine, and overcoming the disappointment that eventually occurs when the limitations of olanzapine become apparent.     

A case of advanced ovarian clear cell adenocarcinoma responding to cisplatin-cyclophosphamide and paclitaxel-carboplatin]

We report a case of stage IV ovarian clear cell adenocarcinoma successfully controlled by a combination of cisplatin-cyclophosphamide (CP) and paclitaxel-carboplatin (TJ). A 64-year-old female with advanced ovarian cancer and pleural effusion underwent 4 courses of combination chemotherapy with CP. The giant ovarian tumor showed a relative reduction in size and the pleural effusion disappeared. Serum CA-125 levels and CA 19-9 levels markedly decreased. Thus, the patient underwent a total hysterectomy and bilateral salphingoophorectomy. During the operation, a giant ovarian clear cell adenocarcinoma was found, but there was no peritoneal dissemination and no cancer cells in her peritoneal fluid. Thereafter, she underwent 3 courses of combination chemotherapy with TJ. She has had 13 months of stable, tumor-free survival since the operation and normal serum CA-125 and CA 19-9 levels. Ovarian clear cell adenocarcinoma generally responds poorly to cisplatin and carboplatin, but in combination chemotherapy with paclitaxel-carboplatin these may be effective.