Antibacterial effect of Ag-containing hydroxyapatite thin film fabricated by sputtering.

BACKGROUND: Infections related to joint prosthesis are still a major concern for orthopedic surgeons. Hydroxyapatite (HA) is a useful biocompatible material because of its good osteocompatibility. Antibacterial HA coatings have been fabricated with addition of antibacterial agents such as Ag to HA using the plasma spraying method. However, the plasma-sprayed HA coating suffers from fractures at large thicknesses. The sputter-coated HA thin film has a high density, and has been applied clinically for dental implants. However, there are no extensive studies on Ag-containing HA thin films. OBJECTIVE: The aim of this study was to prepare an Ag-containing HA thin film by sputtering, and evaluate its antibacterial effect and cytotoxicity. METHODS: The Ag-containing HA thin films were prepared by radio-frequency magnetron sputtering. The films were characterized using X-ray photoelectron spectroscopy, X-ray diffractometry, and scanning electron microscopy (SEM). The antibacterial activities and cytotoxicities of the films were also evaluated. RESULTS: The Ag/Ca molar ratio of the films increased with the Ag ratio in the target. The SEM observation of the hydrothermally treated films showed surfaces covered with globular particles. All Ag-containing HA films exhibited an antibacterial effect against E. Coli. The number of cells of the films decreased with the Ag ratio. The films subjected to the hydrothermal treatment exhibited a higher number of cells than the as-sputtered films. CONCLUSION: The Ag-containing HA thin film was effective in terms of antibacterial effect, and had a low cytotoxicity in the proliferation of osteoblast cells at a low Ag ratio in the target.

Predictive performance of Shock Index for postpartum hemorrhage during cesarean delivery.

BACKGROUND: The Shock Index (SI), defined as heart rate divided by systolic blood pressure, is reportedly an early surrogate indicator for postpartum hemorrhage (PPH). However, most previous studies have used clinical data of women who delivered vaginally. Therefore, we aimed to evaluate the SI pattern during cesarean delivery and determine its usefulness in detecting PPH. METHODS: This was a single-center retrospective study using the clinical data of women (n = 331) who underwent cesarean delivery under spinal anesthesia at term between 2018 and 2021. We assessed the SI pattern stratified by total blood loss and evaluated the predictive performance of each vital sign in detecting PPH (total blood loss ≥1000 mL) based on the area under the receiver operating characteristic curve (AUROC). RESULTS: At 10-15 min after delivery, the mean SI peaked between 0.84 and 0.90 and then decreased to a level between 0.72 and 0.77, which was similar to that upon entering the operating room. Among 331 women, 91 (27.5%) were diagnosed with PPH. There was no correlation between SI and total blood loss (rs = 0.02). The SI had low ability to detect PPH (AUROC 0.54, 95% confidence interval 0.47 to 0.61), which was similar to other vital signs (AUROCs 0.53-0.56). CONCLUSION: We determined the pattern of SI during cesarean delivery. We found no correlation between SI and total blood loss. Unlike in vaginal delivery, the prognostic accuracy of SI for PPH detection in cesarean delivery was low.

Characteristic endoscopic findings of gastrointestinal malignant lymphomas other than mucosa-associated lymphoid tissue lymphoma.

Background and study aims: The gastrointestinal (GI) tract is the most common site of extra-nodal involvement for non-Hodgkin's lymphoma (NHL). The features of GI NHLs remain unclear. The aim of this study was to clarify endoscopic characteristics of GI NHLs. Patients and methods: We retrospectively analyzed the morphological characteristics of 63 GI malignant lymphomas other than mucosa-associated lymphoid tissue lymphoma. Lesions were diagnosed between 2005 and 2020. Macroscopic findings were classified into five subtypes: superficial (S); protruding without ulcer (P); protruding with ulcer (PU); fungating (F); and multiple nodules (MN). Results: Thirty-one lesions in the stomach were classified as S type in 3 cases (9.6%), P type in 6 (19%), PU type in 13 (42%), and F type in 9 (29%). In the stomach, the ulcerated phenotype was more frequent for diffuse large B-cell lymphoma (DLBCL) (89.5%) than for other histological types (41.7%; P = 0.01). In the intestine, 23 tumors were classified as S type in 4 cases (17%), P type in 1 (4%), PU type in 6 (26%), F type in 1 (4%), and MN in 11 (48%). Eleven of the 14 cases (78.6%) of intestinal follicular lymphoma lesions showed MN type. In the colon, eight tumors were classified as S type in 2 cases (25%), P type in 2 (25%), PU type in 1 (13%), and F type in 3 (38%). Conclusion: We have clarified the endoscopic features of GI NHL using macroscopic classifications. The ulcerated phenotype was the most frequent endoscopic finding for DLBCL.

Adsorptive properties of albumin, fibrinogen, and gamma-globulin on fluorinated diamond-like carbon films coated on PTFE.

Fluorinated diamond-like carbon (F-DLC) films were deposited on polytetrafluoroethylene (PTFE) using radio frequency (RF) plasma-enhanced chemical vapor deposition (CVD) by changing the ratio of tetrafluoromethane (CF(4)) and methane (CH(4)). To enhance the adhesion strength of the F-DLC film to the PTFE substrate, the PTFE surface was modified with a N(2) plasma pre-treatment. XPS analysis of the films showed that the C-C bond decreased with increases in the CF(4) ratio, whereas the C-F bond increased with the CF(4) ratio. The F/C ratio of the film also increased with the CF(4) ratio. The pull-out test showed that the adhesion strengths of the films (CF(4)-0-60%) were improved with the plasma pre-treatment. In the film without the plasma pre-treatment, adhesion strength increased with the CF(4) ratio. In contrast, in the case with the plasma pre-treatment, the adhesion strength of the F-DLC film decreased with the increased CF(4) ratio. Regarding the adsorption of albumin, fibrinogen, and gamma-globulin, the amount of adsorbed albumin on the film decreased with an increasing CF(4) ratio, and the amount of adsorbed fibrinogen and gamma-globulin increased with the CF(4) ratio. The CF(4)-0% DLC film showed the most adsorbed albumin and the least adsorbed fibrinogen and gamma-globulin. This indicates that the CF(4)-0% DLC film has higher anti-thrombogenicity than the F-DLC film.

Comparison of stress distribution in partially and completely edentulous mandibles around splinted and non-splinted implant prostheses: A finite element study.

BACKGROUND: In some treatments using multiple dental implants, the implants are inserted in the bone with splinted or non-splinted implant prostheses. There are some reports about the influence of the splinted and non-splinted implants on stress distribution in the bone using the finite element method (FEM), and there is a controversy in the literature regarding whether the splinted or non-splinted implants prostheses reduce the stress generated on the implant-surrounding bone more efficiently. Additionally, the simple shape of the jaw bones with limited bone area was used for FEM analysis in many studies at the expense of accurate analysis. OBJECTIVE: The aim of this study was to evaluate the difference in stress distribution in the bone between the splinted and non-splinted implants, and between completely and partially edentulous mandibles. METHODS: The implants were inserted in the first premolar, second premolar, and first molar regions of the partial and complete mandibles, and the splinted and non-splinted crowns were attached to the implants. Vertical load (100 N) or oblique load (70 N, 30° from its long axis towards the lingual) was applied on the first premolar. RESULTS: When vertical load was applied to the partially edentulous mandible model, the stress was concentrated intensively on the cortical bone around the first premolar regardless of whether splinted or non-splinted implants were used. On the other hand, the vertical load applied to the completely edentulous mandible model caused the stress to be concentrated intensively on the cortical bone around the first premolar with non-splinted implants. With respect to the oblique load, the stress was concentrated intensively on the cortical bone around the first premolar only with the non-splinted implants, in both the partial and complete mandibles. CONCLUSION: This study shows the different stress distributions of the cortical bone around the implants between the partial and complete mandible. This indicates that the complete mandible should be used for the analysis of bone stress distribution around the implants using FEM.

Preparation of aluminosilicate and hydroxyapatite/aluminosilicate composite films with the sputtering technique and their adsorption capacity with cesium and strontium.

BACKGROUND: Removal of radioactive substances, such as cesium (Cs) and strontium (Sr), has become an emerging issue after the Fukushima Daiichi nuclear power plant disaster. It has been reported that hydroxyapatite (HA) and aluminosilicate composite powders can be used to remove Cs and Sr. However, the film type of these materials for the removal of Cs and Sr has not been reported. OBJECTIVE: The aim of this study was to assess the possibility of using HA, aluminosilicate, and aluminosilicate/HA composites for the removal of Cs and Sr radioactive substances. METHODS: Aluminosilicate films and HA films were fabricated using a sputtering technique with diatomaceous earth and HA targets, respectively. The aluminosilicate film was observed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). A comb-shaped HA/aluminosilicate composite film was prepared to take advantage of the adsorption properties of the HA and the aluminosilicate films. The Cs and Sr adsorption on these films were also evaluated. RESULTS: In the XRD patterns, the film sputtered from a diatomaceous earth target under 5.0 Pa of Ar pressure showed aluminosilicate peaks (Na1.82(Al2Si3O10) and Al2SiO5) after 8 h of vapor-phase hydrothermal treatment. The film showed higher adsorption of Cs than Sr in Cs and Sr solutions, while the HA film adsorbed far more Sr than Cs. A HA/aluminosilicate composite film was successfully fabricated, and the SEM images showed that the width of the HA region was 230-260 µm, and that of the aluminosilicate region was 170-200 µm. The HA/aluminosilicate composite film showed 84.8 ± 11.5% Cs adsorption and 28.3 ± 1.4% Sr adsorption in a mixed solution of Cs and Sr. CONCLUSION: This study shows the feasibility of using HA films, aluminosilicate films, and HA/aluminosilicate composite films for the removal of radioactive substances such as Cs and Sr.

Oxygen plasma pre-treatment improves the wear properties of a diamond-like carbon film coated on UHMWPE and PMMA for biomaterials.

Diamond-like carbon (DLC) films were deposited on ultra-high molecular weight polyethylene (UHMWPE) and polymethylmethacrylate (PMMA) with oxygen plasma pre-treatment using a radiofrequency plasma chemical vapour deposition method. A ball-on-disc test was carried out to evaluate the wear properties of the DLC-coated UHMWPE and PMMA. After testing, the surface of the polymers was observed using an atomic force microscope and an optical microscope. The adhesive strength of the DLC films deposited on the polymers was measured using a scratch test. After the ball-on-disc test, many cracks were observed in the films on the surface of both the DLC-coated UHMWPE and PMMA without the oxygen plasma pre-treatment, whereas the DLC-coated UHMWPE and PMMA with oxygen plasma pre-treatment showed no cracks and good wear resistance. In the scratch test, the adhesion strength of the DLC film to the PMMA substrate increased from 42.5 mN to 101.3 mN with oxygen plasma pre-treatment.

Fabrication of hydroxyapatite thin films on polyetheretherketone substrates using a sputtering technique.

Hydroxyapatite (HA) thin films were coated on a polyetheretherketone (PEEK) substrate using a sputtering technique. A thin titanium (Ti) intermediate layer was formed between the HA and the PEEK surface to improve adhesion of the HA film to the PEEK substrate. The coated films were recrystallized using a hydrothermal treatment to reduce the dissolution of the HA film. The films were then characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), and a UV-Vis spectrophotometer. A pull-out test was performed to measure the film-to-substrate adhesion strength, and an immersion test was performed in ultra-pure water. In the XRD patterns of the sputtered film with the Ti intermediate layer on the PEEK substrate, small HA peaks and large Ti peaks were observed. After the hydrothermal treatment, the intensity of the HA peaks increased. The transmittance of the HA films with 5 and 10nm Ti intermediate layers was >79% and 68%, respectively, in the visible light wavelength region (400-700nm) after the hydrothermal treatment. The adhesion strength of the hydrothermally treated HA films increased with decreasing thickness of the Ti intermediate layer, and the strength reached 2.7MPa with the 5-nm-thick Ti intermediate layer. In the immersion test, the HA film with a 5-nm-thick Ti intermediate layer without hydrothermal treatment exhibited a released Ti concentration of 42.0±2.4ppb. After hydrothermal treatment, the released Ti concentration decreased to 17.3±1.1ppb.

Dissolution behavior and in vitro evaluation of sputtered hydroxyapatite films subject to a low temperature hydrothermal treatment.

Hydroxyapatite (HA) was coated onto titanium substrates using radio frequency sputtering. Some of the as-sputtered films were hydrothermally recrystallized at 110 degrees C. In immersion tests, the as-sputtered film completely dissolved after 2 days in a culture medium, whereas the thickness of hydrothermally treated films increased with an increase in immersion period, reaching a thickness of 127% after a period of 4 weeks. The proliferation and alkaline phosphatase (ALP) activity of MC3T3-E1 osteoblast-like cells on the as-sputtered and hydrothermally treated films were investigated, and the cell morphology was also observed using scanning electron microscopy. The proliferation of MC3T3-E1 cells on the as-sputtered films was suppressed, whereas proliferation on the hydrothermally treated films was comparable to that on control and titanium substrate. The suppression of cell proliferation is associated with an increase in pH of the culture medium caused by dissolution of the as-sputtered film. After a 96-h culture time, the ALP activity of the cells on the hydrothermally treated film was higher than that on the control, titanium substrate, and as-sputtered film samples. From scanning electron microscopic observations, it was found that the MC3T3-E1 cells on the hydrothermally treated films were elongated and had established more intricate filopodia networks with each other, which were also observed for MC3T3-E1 cells on the as-sputtered films after a period of 24 h.

Expression and methylation status of the FHIT gene in acute myeloid leukemia and myelodysplastic syndrome.

To clarify the role of fragile histidine triad (FHIT) in hematological malignancies, we examined the methylation status and the expression level of the FHIT gene in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) cells in comparison with the methylation of the p15(INK4B) gene. The FHIT methylation was found in 13 of 94 (13.8%) AML and 22 of 40 (55.0%) MDS cases, but not in normal mononuclear cells (MNCs). Both the frequency and density of methylation increased in the advanced-stages MDS and the relapsed AML cases. Although FHIT and p15(INK4B) methylations were not correlated in MDS and AML, increased FHIT methylation at the relapse in AML was associated with p15(INK4B) methylation. The median expression level in AML was significantly higher than in normal MNCs, although the median expression level in those with methylation was significantly lower than in those without methylation. Furthermore, the methylation level at relapse was significantly higher than at diagnosis in AML. These results suggested that FHIT methylation was accumulated through the disease progression of MDS and AML, and the role of the FHIT gene as a tumor suppressor seemed different in AML and MDS.

Preparation of germanium apatite and its cytotoxicity.

Germanium apatite was synthesized via the solid-state reaction between GeO(2) and (NH(4))(3)PO(4). The synthesized materials were characterized using XRD, and thermal analysis was carried out using TG-DTA. Ge(2)P(2)O(7) was preferentially produced at temperatures between 300-900 degrees C, and at temperatures above 1000 degrees C, germanium apatite (Ge(5)O(PO(4))(6), GeAp) was synthesized. In solubility tests, 0.36% and 0.65% of Ge ions were liberated from GeAp powder in distilled water at 37 and 80 degrees C after four weeks, respectively. A GeAp aqueous solution maintained at 37 degrees C was strongly acidic with a pH=1.67 after four weeks. The growth rate of human adult gingival fibroblast cells in a medium that included GeAp, HA, and GeO(2) was investigated. The growth rate of the cells in a 0.1 mg/ml GeAp medium was almost the same as that in the control. The cell growth was restricted in a 1.0 mg/ml GeAp medium, whereas the cell growth in a pH-adjusted 1.0 mg/ml GeAp medium at pH=7.60 was higher than that in non-adjusted medium at pH = 7.06.

Bone response to titanium implants coated with thin sputtered HA film subject to hydrothermal treatment and implanted in the canine mandible.

Hydroxyapatite (HA) was coated onto titanium implants using radio frequency magnetron sputtering. The HA films were crystallized in an autoclave tube using low temperature hydrothermal treatment. The average film thickness on the implant was 1.1 microm. HA-coated and pure-titanium implants were inserted into canine mandibles for up to 24 weeks. Forty-eight implants were placed in eight beagles. After 2, 4, 12 and 24 weeks, implants were retrieved and prepared for histological observation, and the HA film thickness was determined using energy-dispersive X-ray spectroscopy. Light microscopy revealed that, after two weeks, the bone response to the HA-coated implants was much better than to the pure titanium implants, and osteoblasts were observed at the bone-implant interface. After four weeks, the screw threads of the HA-coated implants were almost completely covered with bone. The HA film thickness rapidly decreased up to four weeks of implantation, then gently decreased, reaching 0.40+/-0.03 microm at the upper region of the implant after 12 weeks. That indicates that about 80% of the HA film had dissolved after 12 weeks of implantation. The rate of decrease in the HA film thickness was greater with increasing implant depth.

Effect of a thin HA coating on the stress/strain distribution in bone around dental implants using three-dimensional finite element analysis.

Three-dimensional finite element analysis was performed for thin hydroxyapatite (HA) coated and titanium dental implants to study the effects on stress/strain distribution in the mandible with application of axial and oblique loads. The implants were of screw and cylinder types. With an axial load, the maximum equivalent bone stresses in the titanium implants were 21.5 and 29.0 MPa for the cylinder and screw types respectively, and the stress and strain distributions differed. For the cylinder type, the highest stress was located at the implant base, and for the screw type, it was located at the top edge of the first thread within the cortical bone. For the HA-coated cylinder and screw implants, the maximum equivalent bone stresses were 7.1 and 7.2 MPa respectively. The stress and strain distributions were similar, and the highest stress was located on the upper side of the cortical bone around the implant neck for both implants. Of the implants examined, the screw type HA-coated implant had the most uniform stress distribution in bone.

Evaluation of the adsorptive behavior of cesium and strontium on hydroxyapatite and zeolite for decontamination of radioactive substances.

Removal of radioactive substances, such as cesium (Cs) and strontium (Sr), has become an emerging issue after the Fukushima Daiichi Nuclear Power Plant Disaster. To assess the possibility that hydroxyapatite (HA) and zeolites can be used for removal of radioactive substances, the adsorption capacities of Cs and Sr on the HA and a zeolite were investigated. The influence of Fe ions on Cs and Sr adsorption on the HA and the zeolite was also evaluated, because Fe ions are the most effective inhibitor of Cs adsorption on the zeolite.In the Cs adsorption process on the HA and the zeolite, the zeolite showed a higher adsorption ratio than the HA, and the maximum sorption capacity of the zeolite was calculated as 196 mg/g, whereas the HA showed a higher Sr adsorption ratio than the zeolite. The maximum sorption capacity of Sr on the HA was 123 mg/g. Under coexistence with Fe, Cs adsorption on the zeolite decreased with increasing Fe concentration, reaching 2.0 ± 0.8% at 0.1 M Fe concentration. In contrast, Cs adsorption on the zeolite was improved by adding the HA. In the case of coexistence of the HA, the Cs adsorption on the mixture of the HA and the zeolite was 52.4% ± 3.6 % at 0.1 M Fe concentration, although Cs adsorption on the HA alone was quite low. In the Fe adsorption processes of the HA and the zeolite, the HA exhibited a maximum sorption capacity of 256 mg/g, which was much higher than that of the zeolite (111 mg/g). The high affinity of Fe on the HA contributes to the improvement of the deteriorated Cs adsorption on the zeolite due to Fe ions.

Control system renewal for efficient operation in RIKEN 18 GHz electron cyclotron resonance ion source.

A RIKEN 18 GHz electron cyclotron resonance ion source (18 GHz ECRIS) is used as an external ion source at the Radioactive Ion Beam Factory (RIBF) accelerator complex to produce an intense beam of medium-mass heavy ions (e.g., Ca and Ar). In most components that comprise the RIBF, the control systems (CSs) are integrated by the Experimental Physics and Industrial Control System (EPICS). On the other hand, a non-EPICS-based system has hardwired controllers, and it is used in the 18 GHz ECRIS CS as an independent system. In terms of efficient and effective operation, the 18 GHz ECRIS CS as well as the RIBF CS should be renewed using EPICS. Therefore, we constructed an 18 GHz ECRIS CS by using programmable logic controllers with embedded EPICS technology. In the renewed system, an operational log system was developed as a new feature, for supporting of the 18 GHz ECRIS operation.

Note: Effect of hot liner in producing 40,48Ca beam from RIKEN 18-GHz electron cyclotron resonance ion source.

In order to produce a high-intensity and stable (48)Ca beam from the RIKEN 18-GHz electron cyclotron resonance ion source, we have begun testing the production of a calcium beam using a micro-oven. To minimize the consumption rate of the material ((48)Ca), we introduced the "hot liner" method and investigated the effect of the liner on the material consumption rate. The micro-oven was first used to produce the (48)Ca beam for experiments in the RIKEN radioisotope beam factory, and a stable beam could be supplied for a long time with low consumption rate.

Influence of the crystallinity of a sputtered hydroxyapatite film on its osteocompatibility.

Hydroxyapatite (HA) was coated onto titanium substrates using radio frequency sputtering, and the sputtered films were crystallized using a hydrothermal treatment at 120°C and 170°C to evaluate the influence of the crystallinity of the HA film on its osteocompatibility. The crystallite size and surface morphology of the films were observed using X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The alkaline phosphatase (ALP) expression, osteocalin (OCN) expression and bone formation of osteoblast cells on the films were measured to evaluate the osteocompatibility of the film.The crystallite size increased as the hydrothermal temperature increased, and the crystallite sizes of the film treated at 120°C and 170°C were 82.2±12.3 nm and 124.7±13.3 nm, respectively. Globular particles were observed in the hydrothermally treated film using SEM. The size of the particles on the film increased as the hydrothermal temperature increased, and the width of the particles on the film treated at 120°C and 170°C were approximately 120-190 nm and 300-500 nm, respectively. In the osteoblast cell culture experiments, the ALP expression, OCN expression and bone formation area on the films treated at 120°C were higher than those treated for films treated at 170°C.

Isolation of a new lytic enzyme for hiochi bacteria and other lactic acid bacteria.

A microorganism producing a lytic enzyme preparation that could rapidly lyse bacterial cells such as hiochi bacteria and other lactic acid bacteria was screened. The microorganism was identified as Streptomyces fulvissimus. The enzyme produced by this organism lysed boil-denatured cells quicker than intact cells of hiochi bacteria. A mutant strain of S. fulvissimus producing the enzyme exhibiting high activity against intact cells of hiochi bacteria was screened on plates, containing intact cells inactivated with UV irradiation. The optimal pH for lytic activity against intact cells of the hiochi bacterium Lactobacillus casei S-4 was from 3.5 to 4.0, and the optimum temperature was close to 50 degrees C. This enzyme activity was stable between pH 3.5 and pH 8.0 and up to 60 degrees C. The enzyme exhibits N-acetyl glucosaminidase and muramidase activities. The effects of adjusting the pH and using different inducers for enzyme production were investigated. Chitin was the most effective inducer of enzyme production. Intact DNA was easily isolated from the cells of many lactic acid bacteria following lysis with the enzyme. It is thought that this enzyme will be a good biotechnological tool.

Scanning electron microscopy of ciliary zones of the ciliate protozoa in the large intestine of the horse.

The surface structure of the ciliary zone in 13 species of ciliates found in the large intestine of the horse was observed by scanning electron microscopy. In Holophryoides ovalis many fine depressions considered to be a result of phagocytosis or pinocytosis in the naked cytostome were noticed. In Blepharocorys spp. a distinct section was present between the portion with cilia and that without cilia. It was not present, however, in some species of the family Buetschliidae, such as Bundleia postciliata and Didesmis spp. The species of Entodiniomorphida had a lip around the ciliary zone with cilia forming synciliary tufts. In Spirodinium equi and Tetratoxum unifasciculatum the ciliary zone revolved counter-clockwise in an en face view. Some differences in the surface structure of the ciliary zone between the entodiniomorphid and spirotrich ciliates are discussed.

Inhibition of Ni release from NiTi alloy by hydroxyapatite, alumina, and titanium sputtered coatings.

To alleviate the effects of Ni allergy from NiTi alloy implants, hydroxyapatite (Ca10(PO4)6(OH)2; HA), alumina (Al2O3), or titanium (Ti) was coated onto NiTi alloy plates to form 1-microm thick films using radio frequency magnetron sputtering. The coatings on the plates were characterized using XRD. After the plates had been immersed in physiological saline for periods of one, four, or eight weeks, the concentration of Ni ions released in each solution was detected using a microwave induced plasma mass spectrometer. After eight weeks, the concentration of Ni ions released from the non-coated, the Ti-coated, the HA-coated, and the alumina-coated plates were 238, 19.7, 183, and 106 ppb, respectively. The bonding strength of the Ti film, the HA film, and the alumina film to the NiTi substrate were 3.8 +/- 1.2, 2.6 +/- 0.7, and 3.1 +/- 1.2 MPa, respectively. The non-coated, the HA-coated, the alumina-coated, and the Ti-coated plates were implanted into the femurs of a dog for four weeks for histological observation. In case of the non-coated plates, connective tissue more than 300 microm thick was observed, whereas for the coated plates the thickness of the connective tissue was around 100 microm.