Potential for acceleration of bone formation after implant surgery by using a dietary supplement: an animal study.

Dental implant treatment is an effective modality to restore lost aesthetic and masticatory functions. However, healing after implant surgery takes at least 3-6 months. This prolonged healing period poses several difficulties for individuals with a large edentulous area and decreases their quality of life. Consequently, shortening the healing period and accelerating final prosthesis placement after surgery is very clinically important. Peri-implant bone formation may be enhanced by systemic approaches, such as the use of osteoporosis supplements, to promote bone metabolism. To confirm whether intake of a supplement developed for osteoporosis, synthetic bone mineral (SBM), was effective in accelerating peri-implant bone formation as part of the healing process after implantation. Twenty-four 5-week-old female Wistar rats were randomly assigned to receive a standardised diet without (control group, n = 12) or with SBM (n = 12). The rats had implant surgery at 8 weeks of age under general anaesthesia. The main outcome measures were bone mineral density (BMD) and pull-out strength in the implant and femur, which were compared between the groups at 2 and 4 weeks after implantation using the Mann-Whitney U test. BMD was significantly greater in the SBM group at 2 and 4 weeks after implantation compared to the control group. Pull-out strength was significantly greater in the SBM groups at 2 and 4 weeks after implantation compared to the control group. This study demonstrated that SBM could be effective in accelerating peri-implant bone formation during the healing period after implantation.

Investigation of the neutron spectrum measurement method for dose evaluation in boron neutron capture therapy.

In boron neutron capture therapy, it is important to evaluate the dose administered to a patient's body outside the tumour area. The exposure dose is evaluated by calculation; however, the calculated value must be validated using a measured value. The dose evaluations based on the measured neutron spectrum are investigated. Multi-foil activation, combined with a LiCaAlF6 scintillation detector and an imaging plate, is proposed as a measurement method. The proposed method can measure the neutron spectrum at various points quickly.

Effect of fluoride ions on apatite crystal formation in rat hard tissues.

Fluoride is widely believed to be a useful chemical substance for preventing dental caries. However, the mechanism underlying crystal perforation in the tooth enamel and the effect of fluoride on hard tissues are unclear. To clarify the mechanism of the biological action of fluoride in the mineralization process, we examined the hard tissues of rats having received water containing a relatively low fluoride level. Electron microscopy revealed that fluoride ions could interrupt the crystal nucleation process, resulting in crystal perforation in the developing tooth enamel and the presence of amorphous minerals in bone crystals. Furthermore, the results of enzymatic analyses indicated that fluoride directly interfered with the synthesis of carbonic anhydrase by the enamel-forming cells, rather than being directly involved in the crystal formation. From the results, we would like to provide a possible mechanism of crystal perforation in the enamel induced by fluoride intake. Also, we would like to suggest that regardless of its amount, fluoride intake has harmful effects on both tooth and bone formation.

Demonstration of structural variation in rat incisor dentin as determined by the x-ray Laue method.

Rat incisor dentin was studied by an x-ray micro-Laue method to investigate the relationship between crystal orientation and structural variation in the dentin. The results showed that crystal orientation was very poor in the labial dentin, but that the crystals were well-oriented in the lingual dentin. In the lingual dentin, the axis of crystal orientation was parallel to the tooth axis. It is suggested that the difference in crystal orientation between the lingual and labial dentin is due to the different mode of calcification between the two.

Changes in bovine dentin mineral with sodium hypochlorite treatment.

Dentin powders from bovine incisors were treated with 10% NaClO solution. Differential thermal analysis (DTA) indicated the removal of organic material from the dentin sample following the treatment, since the exothermic reaction at 320 degrees C had disappeared. X-ray diffraction studies revealed a change in the crystallinity of the dentin crystals and the formation of calcite after the treatment. Infrared absorption analysis showed that the band due to carbonate ions was weakened after the treatment, while atomic absorption spectroscopic analysis showed that magnesium ions had been dissolved from the dentin sample. The a-axis lengths of treated and heated dentin samples differed from those of untreated and heated samples. Whitlockite was always found in the untreated/heated samples, whereas it was absent in the treated/heated samples. The unit cell dimensions of the whitlockite indicated the partial substitution of magnesium for calcium. Magnesium ions seemed to be more effective than carbonate ions in forming whitlockite. These results showed that some magnesium and carbonate ions were removed from the dentin crystal structure upon NaClO treatment, while at the same time organic materials were removed from the dentin sample. It was suggested that crystals in the NaClO-treated dentin were similar to enamel crystals from a crystallographic viewpoint.

Mode of occurrence of brushite and whitlockite in a sialolith.

A micro-focus X-ray diffractometer was applied to a ground section of sialolith, and localization of brushite and whitlockite was found. The sialolith was composed of a central core of organic material and a layered cortex of mineral components. The major component of the mineral cortex is apatite. Brushite and whitlockite locate independently at the surface layer of the cortex.

Weddellite in submandibular gland calculus.

Scanning electron microscopy of a submandibular sialolith showed octahedral and dipyramidal crystals located at the surface layer of cortex. The crystal habits observed were consistent with those of a tetragonal crystal system. X-ray microdiffraction revealed the presence of weddellite. The origin of weddellite within the calculus remains to be determined.

Dosimetry of pulsed clinical proton beams by a small ionization chamber.

Response of a micro volume (0.01 ml) ionization chamber has been studied with pulsed proton beams which are used for clinical purposes and has been compared with those of some JARP ionization chambers (0.6 ml). All chambers used had been calibrated by standard 60Co beams at the Electrotechnical Laboratory (ETL) and exposure calibration factors, Nx, were obtained on advance. Two methods are used to compensate the general recombination which occurs during pulsed beam irradiations: theoretical correction by a Boag's formulation and a modified two-voltage technique. An evaluation of absolute absorbed dose-to-water is performed on the basis of the protocol provided by ICRU report 59. The results imply that, to a first approximation, both chambers indicate the almost same result within 2% when unknown chamber-dependent parameters of the micro chamber are tentatively assumed to be identical to those of the JARP chamber for the calibration with 60Co beams. The about 1.5% discrepancy observed in the response of both chambers is not discussible due to presumably 1-2% uncertainty of the protocol of ICRU report 59 which does not include any chamber-dependent corrections for the perturbation effects in proton beams.

Multi-layer energy filter for realizing conformal irradiation in charged particle therapy.

A new type of filter for charged particle radiotherapy is developed to reduce unwanted dose transfer to the normal tissues around a tumor. The new filter can make a static irradiation field where the width of the spread-out Bragg peak (SOBP) is two-dimensionally adjusted. That makes the field conformal to the tumor three-dimensionally. The filter is made of many layers produced by using stereolithography. The layer has a miniaturized structure that has geometrical similarity to the conventional ridge filter. Shapes of cone and pyramid are also usable for the unit-cell constructing the layer. The spread of the field in the depth direction is decided by the thickness of the filter, or by the number of layers. The experimental result of the irradiation using the ridge-type construction shows a good agreement with an estimate by the Monte Carlo calculation. By combining this technique with intensity modulation that has lateral position dependence, the conformal irradiation can be achieved by a simple procedure.

Acute spinal cord injury: magnetic resonance imaging correlated with myelopathy.

Thirty-one patients (29 males and two females, 13-87 years of age (mean, 46.7 years] with acute spinal cord injury were studied by MR (magnetic resonance) imaging and the results were correlated with neurological findings. Magnetic resonance images were obtained with a 0.5 T superconductive MR scanner (Phillips Gyroscan S5). Initial imaging was performed within 24 hours after trauma in 13 patients, 1-7 days in 13 patients and 7-14 days in five patients. Twenty-six patients underwent follow-up examinations with MR imaging. Cord abnormalities including cord compression (23 patients), cord swelling (seven patients), and abnormal signal intensities on either T1 or T2-weighted images (26 patients) were observed on initial examination. Multivariate analysis showed that cord compression and abnormal intensities on T1-weighted images were important prognostic indicators. Hyperintensity on T2-weighted images was non-specific but correlated well with clinical recovery. Magnetic resonance imaging is useful in predicting the prognosis and for planning treatment following spinal cord injuries.

Phlebolithiasis associated with intramuscular hemangioma. X-ray diffractometric, X-ray microanalytical and scanning electron microscopic investigations.

Phlebolithiasis associated with intramuscular hemangioma is relatively rare. Combined crystallographic, microanalytical and morphological studies have not been done before. We investigated a case of phlebolithiasis by scanning electron microscopy, X-ray microdiffractometry and energy-dispersive X-ray microanalysis. The calculus revealed a lamellar structure with irregular distribution of radipaque and radiolucent portions. The radiopaque portions contained apatite which could be demonstrated in prismlike as well as globular granular structures. In contrast to other authors, brushite was not detected by us. The radiolucent protions adjacent to the stone surface contained sulfur and showed undefined diffraction peaks supposing the presence of organic crystals. The possible milieu factors govering calculus formation are discussed.

X-ray diffraction and thermal studies of crystals from the outer and inner layers of human dental enamel.

X-ray diffraction showed that crystals from the outer layer had larger crystallite sizes, a-axis length and peak intensities than the inner layer crystals. Upon heating, apatites in both layers showed a contraction of a-axis length and changed their crystallite sizes along the direction of the a-axis independently of changes along the c-axis. The contraction of the a-axis length is attributed to loss of structurally incorporated water from the apatite lattice, causing void formation along the c-axis and altering the crystallite size normal to the c-axis. Whitlockite was detected in samples from both layers at temperatures above 800 degrees C, and the temperature required for whitlockite formation was considered to be influenced by the experimental atmosphere. The peak shift of whitlockite with temperature indicates that the whitlockite initially formed was magnesium rich. As to the amount of structurally incorporated water in both layers' apatites, the a-axis contraction data were inconsistent with the a-axis length data. This inconsistency indicates a larger degree of magnesium substitution in the inner layer apatite. A larger degree of magnesium substitution in apatite would show a smaller crystallite size, a weaker apatite peak intensity and a larger amount of whitlockite formation.

Correlation of sequential MR imaging of the injured spinal cord with prognosis.

Forty-nine patients with acute spinal cord injuries were studied sequentially with MR imaging by using 0.5 Tesla superconductive units, and sequential MR changes were correlated with the prognosis of the patients. MR images were obtained within one week of the injury and then every two to six months when possible. The Frankel classification of neurologic function was correlated with MR findings. The most frequently observed types of signal intensity patterns on MR imaging were type 0 (isointensity on both T1- and T2-weighted images) and type I (isointensity on T1- and hyperintensity on T2-weighted images). In subsequent subacute and chronic stages, type II (hypointensity on T1 and hyperintensity on T2) was most frequently observed. The evolution of type 0 was to types I and II, whereas type I usually turned into type II or remained as type I. Type III (hyperintensity on T1 and hyper-, iso- or hypointensity on T2 images) patients were few in number. There was a good correlation between MR imaging patterns and neurologic recovery for initial and subsequent MR patterns, in that type 0 showed good recovery, whereas types I and II revealed good improvement or no recovery. In addition, the extent of the high signal intensity area on initial as well as on subsequent T2-weighted images was proportionally correlated to neurologic recovery. The degree of cord compression was also important for predicting recovery of neurologic function. Findings of MR imaging of acutely injured spinal cord suggested the prognosis of spinal cord injury, especially when sequential studies were obtained.

Indoor concentrations of 220Rn and its decay products.

The distribution of 220Rn atoms in a room was derived from the diffusion equation. The activity concentrations of 212Pb and 212Bi were obtained in relation to 220Rn exhalation rate from a concrete wall. Near the surface of the concrete wall, the radiation exposure due to inhalation of 220Rn decay products may be significant in some cases.

Application of high resolution microfocus X-ray CT for the observation of human tooth.

The calcification degree of extracted human teeth was observed by using high resolution microfocus X-ray CT. As samples, upper and lower first premolars extracted from a 21-year-old female were used. The computed tomograms were produced by high resolution microfocus X-ray CT with a open vacuum X-ray source, rotating sample stage, and image sensor. The distinction between enamel and dentin was very clear, and the shape of the pulp cavity was also clearly identified. The secondary dentin was visible in the circumpulpal dentin. The color map displays showed the heterogeneity of the calcification degree not only in the dentin but also in the enamel. The enamel was divided into three layers according to the calcification degree. High resolution microfocus X-ray CT was very useful for the observation of the internal structure of human teeth without destroying the samples.

[Multiple cerebral arteriovenous malformations: case report].

A ten-year old girl with right occipital multiple arteriovenous malformations (AVMs) is reported. The clinical presentation at the onset of hemorrhage included coma and signs of tentorial herniation. CT after injection of contrast medium revealed an inhomogenous enhanced lesion in the right occipital lobe. Angiography demonstrated a large plexiform AVM and two AV fistulas, each of which had a different arterial supply and different venous drainage. Three operations successfully removed all the AVMs. Operative findings indicated that the lesion consisted of 4 different AVMs. The patient has recovered very well. Case histories and therapeutic and etiological considerations are discussed.

[Orbital varix presenting orbital apex syndrome].

On 7 July 1993, a 61 year-old female presented a seven-day history of double vision and retro-ocular pain. Neurological examination on admission demonstrated right oculomotor palsy and pain in the right frontal nerve. Routine CT scan and MRI disclosed no abnormalities. Her symptoms deteriorated progressively and increased in severity, resulting in complete ptosis and visual disturbance in the right eye, for which she was hospitalized. Angiography also failed to demonstrate any lesion. Herrical CT scan demonstrated a small mass lesion at the right orbital apex. A frontotemporal extradural approach operation was performed on July 6, 1993. The anterior clinoid process and minor wing of the sphenoid were drilled to expose the optic canal and the superior orbital fissure. When the periorbita just beside the optic sheath was opened, a large vein was observed to be impinging on the optic nerve and nerves which pass through the superior orbital fissure. This vein was carefully dissected, coagulated and removed. The postoperative course was uneventful. Her severe retro-ocular pain completely disappeared immediately after the operation. Although complete remission of ptosis and return of eye movements to normal were noted, her visual acuity is at present limited to hand movement. Orbital varix is a common cause of unilateral intermittent proptosis. However, there has been no report in the literature of orbital varix with orbital apex syndrome as the initial clinical appearance. In this type of patient with orbital varix and retrobulbar hemorrhage or impairment of intraorbital nerves, surgical intervention using a transcranial approach to the lesion should be undertaken.

[Intra-arterial infusion chemotherapy with docetaxel for locally advanced breast cancer and inflammatory breast cancer].

From 1998 to 2000, we performed neoadjuvant intra-arterial infusion chemotherapy using docetaxel (60 mg/m2) a few times with 5 patients with local advanced breast cancer and inflammatory breast cancer. Therapeutic effects included 3 cases of PR among the breast tumor patients and downstaging was obtained 2 cases. No critical side effects were found due to this chemotherapy. We could perform mastectomy in all the cases. We consider intra-arterial infusion using docetaxel to be highly effective with few side effects in cases of advanced breast cancer.

[Good response in case of hepatocellular carcinoma with portal tumor thrombs--a case report of interdisciplinary local therapy].

A 56-year-old male patient with chronic C type hepatitis had HCC which invaded right portal vein trunk (Vp3). In August 2000, we performed intrahepatic artery infusion chemotherapy with CDDP and 5-FU under subcutaneous interferon alpha treatment. In addition, we used chemoradiation therapy for portal tumor thrombus in HCC. As the result of such therapy, the size of HCC and portal tumor thrombus reduced and the level of PIVKA-II decreased. There were no side effects except fever due to interferon alpha treatment. In February 2001, we performed devascularization and RFA therapy for HCC in S7 of liver under laparoscope. The level of PIVKA-II was within the normal range. It is important to perform interdisciplinary therapy appropriate for the HCC status.

Project for the development of the linac based NCT facility in University of Tsukuba.

A project team headed by University of Tsukuba launched the development of a new accelerator based BNCT facility. In the project, we have adopted Radio-Frequency Quadrupole (RFQ)+Drift Tube Linac (DTL) type linac as proton accelerators. Proton energy generated from the linac was set to 8MeV and average current was 10mA. The linac tube has been constructed by Mitsubishi Heavy Industry Co. For neutron generator device, beryllium is selected as neutron target material; high intensity neutrons are generated by the reaction with beryllium and the 80kW proton beam. Our team chose beryllium as the neutron target material. At present beryllium target system is being designed with Monte-Carlo estimations and heat analysis with ANSYS. The neutron generator consists of moderator, collimator and shielding. It is being designed together with the beryllium target system. We also acquired a building in Tokai village; the building has been renovated for use as BNCT treatment facility. It is noteworthy that the linac tube had been installed in the facility in September 2012. In BNCT procedure, several medical devices are required for BNCT treatment such as treatment planning system, patient positioning device and radiation monitors. Thus these are being developed together with the linac based neutron source. For treatment planning system, we are now developing a new multi-modal Monte-Carlo treatment planning system based on JCDS. The system allows us to perform dose estimation for BNCT as well as particle radiotherapy and X-ray therapy. And the patient positioning device can navigate a patient to irradiation position quickly and properly. Furthermore the device is able to monitor movement of the patient׳s position during irradiation.