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Biomedical subjects

T Hanawa

Publications and source records attributed to T Hanawa.

At least 91 records · Page 5Linked to original sources
PubMed1991

Cytotoxicity of amalgams, alloys, and their elements and phases.

The purpose of this study was to compare the relative cytotoxicity of amalgams, alloys, and their constituent elements and phases, by means of a rapid and sensitive in vitro cell culture test. Pure copper and zinc showed intensive cytotoxicity, significantly greater than that of pure silver and mercury. Pure tin was non-cytotoxic. The gamma-one phase (Ag2Hg3) revealed moderate cytotoxicity, which was significantly decreased by the addition of 1.5% and 5% Sn. However, the addition of 1.5% Zn to gamma 1 containing 1.5% Sn dramatically increased the cytotoxicity of gamma 1 to the same level as that of pure zinc. Whenever zinc was present in amalgams, higher cytotoxicity was revealed. High-copper amalgams showed the same cytotoxicity as a zinc-free low-copper amalgam. The addition of selenium did not reduce the cytotoxicity of amalgam. The cytotoxicity of amalgams was reduced after 24 h. The results of this study suggest that the major contributor to the cytotoxicity of alloy for amalgam is probably copper, while that for amalgam is zinc.

Copper↗
PubMed1991

Calcium phosphate naturally formed on titanium in electrolyte solution.

Surface films formed on titanium specimens immersed in electrolyte solutions (pH 4.5, 5.2, 7.4) at 37 degrees C for 1 h, 1 d, 30 d, and/or 60 d, were characterized using X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared reflection absorption spectroscopy (FTIR-RAS) to understand the reaction between titanium and inorganic ions. For comparison, the surface of Ti-6AI-4V and Ti-50Ni were also characterized. XPS data revealed that calcium phosphates were naturally formed on these specimens. In particular, compared with the calcium phosphates formed on the titanium alloys, the calcium phosphate formed on titanium immersed for 30 d in the solution with pH 7.4 was more like hydroxyapatite. The compositions of the calcium phosphates formed on the specimens changed with the immersion time and the pH value of the solution. The spectrum obtained using FTIR-RAS from titanium immersed in the solution with pH 7.4 for 60 d was similar to that obtained from carbonate-containing hydroxyapatite. The results indicate that a calcium phosphate similar to apatite is naturally formed on titanium in a neutral electrolyte solution in 30 d. In regard to titanium being a biomaterial, we found this to be an intriguing property. It is possible that this calcium phosphate is responsible for the resulting biocompatibility of titanium.

Alloys↗
PubMed1990

Dynamic mechanical properties of dental amalgams.

The dynamic mechanical properties of two high-copper amalgams (Tytin and Dispersalloy) and two traditional amalgams (Aristalloy and Aristalloy with Zn) were measured over a temperature range of 0-70 degrees C and at frequencies of 0.1, 1, and 10 Hz by means of a DuPont DMA. Values of storage modulus (E') for the amalgams were equivalent to the Young's modulus (E) measured from static mechanical test methods, with Dispersalloy demonstrating the highest moduli. Values of E' decreased with increased temperature. E' of traditional amalgams decreased more rapidly than did those of the Cu-rich amalgams. Values of loss modulus (E") for Tytin were smaller than those of Dispersalloy and the two types of Aristalloy. High values of E" for the traditional amalgams correspond to a greater viscous behavior. Marked differences between the magnitude of tan delta and its temperature coefficients for traditional and high-copper amalgams were observed, which is indicative of differences in visco-elastic behavior between these two amalgam systems.

Copper↗
PubMed1990

[Transverse strength and acoustic emission characteristics of commercial denture base resins].

Transverse strength and acoustic emission (AE) characteristics were measured by the transverse test in deionized water at 37 degrees C on commercial denture base resins (five heat-cured type resins and one polysulfone). Difference in flexural property of five heat-cured denture base resins was not shown from the transverse deflection according to JIS, but high toughness of polysulfone was recognized in transverse deflection, flexural strength, flexural modulus, flexural rigidity, flexural proof stress, and fracture energy. The five heat-cured denture base resins showed a low AE activity, but the polysulfone resin high AE activity. Significant rates of AE for polysulfone were detected at a kgf of approximately 50-60% the maximum load. The presence of Kaiser effect in its cycle transverse test was confirmed.

Acoustics↗
PubMed1990

Development of a new surgical procedure for repairing tracheobronchomalacia.

We have developed a new surgical method for repairing tracheobronchomalacia. In experiments on dogs we tried external fixation of Marlex mesh (Bard Cardiosurgery Division, Bellerica, Mass.) on the trachea. We first made models of tracheomalacia by making fractures or resections in intrathoracic tracheal cartilages and then made an external fixation of Marlex mesh on the malacic segments of the trachea. In 11 dogs Marlex mesh was sutured onto the trachea with absorbable thread. The trachea was firmly supported after 2 to 6 months, compared with three controls in which no external fixation was made. However, mucosal defects associated with ischemia caused by the suture developed in four of the 11. In 13 more dogs Marlex mesh was bonded to the trachea with fibrin glue. After 3 to 8 months the supporting strength of the trachea increased up to the level of the normal trachea. There was no evidence of inflammation or of mucosal defects. Therefore Marlex mesh was applied to a 44-year-old-man who had experienced frequent attacks of cough syncope. After the operation the attacks of cough syncope and collapsing of his airway disappeared completely.

Adult↗
PubMed1990

[Experimental and clinical results of tracheal prosthesis].

Prosthetic reconstruction of the trachea was performed experimentally in mongrel dogs. Neville's prosthesis, which we used initially, has insufficient elasticity and flexibility. As a result, migration was observed after the reconstruction. To prevent such migration, we wrapped the prosthesis in Marlex mesh. Nevertheless, dehiscence and local infection occurred at the anastomotic site. We have developed a new Katsura prosthesis which is made of silicone rubber and has good elasticity and flexibility. However, the Katsura prosthesis was also unable to prevent dehiscence and local infection at the anastomotic site in the experiment. We have thus tested successive models of the Katsura prosthesis (model I-model V). Recently, we wrapped the prosthesis of model V in pedicled omentum instead of Marlex mesh to prevent the spread of infection to the mediastinum. In clinical cases who had a large surgical defect of the trachea and difficulty of primary anastomosis, we performed prosthetic reconstruction. We used Neville's prosthesis in 7 cases and the Katsura prosthesis in 5 cases. Severe complications were observed, such as arterial erosion and migration of the prosthesis. All the cases have died, although 5 cases survived for more than 1 year, and the longest survival time was 43 months. In the future, we hope that an ideal substitute for the trachea will be found and that prosthetic reconstruction will be able to safely performed, as in the case of vascular prosthesis.

Animals↗
PubMed1989

[Clinical evaluation of serum CA130 in patients with lung cancer].

CA130 is a glycoprotein which is recognized by monoclonal antibodies-(130-22 and 145-9) produced by immunization with human lung adenocarcinoma cell line (PC-9). CA130 is considered to be a new tumor marker, different from CA125, since it has a separate antigenic determinant. We used the D-7111 kit (Daiichi Radioisotope Laboratories, Ltd.) to measure the serum level of CA130 in 290 patients with lung cancer, 171 patients with noncancerous lung disease (N-CLD) and 93 healthy adults. In addition, CEA, CA19-9, CA125 and sialyl SSEA-1 antigen (SLX) were also measured for the same serum samples when possible. The cutoff level for CA130 was 35 U/ml. The overall positive rates for CA130 were 32% in the lung cancer patients, 23% in the N-CLD patients and 0% in the healthy adults. The positive rate in the lung cancer patients was significantly higher than in the N-CLD patients (p less than 0.05). As a function of the histological type of lung cancer, the positive rates for CA130 were 44% in 120 patients with adenocarcinoma, 17% in 115 patients with squamous cell carcinoma, 33% in 36 patients with small cell carcinoma, 42% in 12 patients with large cell carcinoma and 29% in 7 patients with miscellaneous cell type. The positive rate in the patients with adenocarcinoma was significantly higher than in the patients with squamous cell carcinoma (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1989

[Evaluation of sialyl SSEA-1 antigen in patients with lung cancer].

Stage-specific embryonic antigen-1 (SLX) is a glycolipid recognized by a monoclonal antibody (FH 6) which is produced by cells immunized with mice teratocarcinoma cell line. Using an SLX (Otsuka) kit from Ostuka Assay Laboratory, we measured the serum level of SLX in 96 patients with lung cancer, 305 patients with non-cancerous lung disease and 86 healthy adults, prospectively. When we adopted a cutoff level of 42U/ml (mean + 2S.D. in the healthy adults), the overall positive rates were 29.2% in the lung cancer patients, 15.1% in the non-cancerous patients and 0% in the healthy adults. The positive rate of the lung cancer patients was significantly higher than in the patients with non-cancerous lung disease (p less than 0.05). According to the histological type of lung cancer, the positive rates were 40.9% in 44 patients with adenocarcinoma, 18.4% in 37 patients with squamous cell carcinoma, 0% in 7 patients with small cell carcinoma, and 0% in 3 patients with large cell carcinoma. Staging of the lung cancer patients revealed positive rates for serum SLX of 5.6% in 18 stage I patients, 22.2% in 9 stage II patients, 33.3% in 21 stage IIIA patients, 33.3% in 27 stage IIIB patients, 42.9% in 21 stage IV patients. After we performed the immunostaining method for SLX using FH6, positive immunoactivity was demonstrated mainly in the cell membrane of adenocarcinoma cells. SLX seems to be a tumor-associated marker in patients with lung adenocarcinoma.

Adenocarcinoma↗
PubMed1989

[Characterization of surface films formed on titanium in electrolytic solutions].

In order to understand the interface-phenomena between titanium and biological tissue, the surface film formed on titanium in electrolytic solutions was examined using X-ray photoelectron spectroscopy (XPS). The composition of the surface film on titanium before immersion into solution is close to TiO2 and that of Ti-6 Al-4 V is a mixture of TiO2 and Al2O3. These surface films change to a complex phosphate of titanium and calcium containing hydroxyl radicals and hydrates when the specimens are immersed in an electrolytic solution. The compositions of the surface films of titanium and Ti-6 Al-4 V are almost the same except that the film on Ti-6 Al-4 V is thicker and contains more hydrates than that on titanium. Vanadium in Ti-6 Al-4 V, and sodium, chlorine, and sulfur in the solution are not responsible for the formation of the films.

Aluminum Oxide↗
PubMed1989

[Direction of amino acid adsorbed by surface film on titanium].

The purpose of the study was to investigate the influence of the isoelectric point and residue of an amino acid on the adsorption of the amino acid by titanium in order to elucidate the adsorption of proteins by titanium. The direction of amino acid adsorbed by a titanium surface in an electrolytic solution was determined using X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared reflection absorption spectroscopy (FT-IR-RAS). Apparently, the influence of amino acid on the composition and thickness of surface films on titanium is minimal if the film is formed in an electrolytic solution. The pH of the electrolytic solution and the residue of amino acids are responsible for the direction of the amino acid adsorbed by surface film formed on titanium in solution.

Adsorption↗
PubMed1989

[Normalizing method for determining the mode of crack-propagation in amalgams and composite resins].

A normalizing method for determining the mode of crack-propagation in a phase or component of a dental amalgam or composite resin was devised. The results calculated using the method were found to be satisfactory when the method was applied to the materials. Furthermore, details of the mode of crack-propagation in the materials which cannot be seen using pictures of the cross-section structure of the materials are revealed using the method.

Composite Resins↗
PubMed1989

[Clinical efficacy of fluconazole in the patient with pulmonary mycosis].

Fluconazole, a novel triazole antifungal agent, was given orally or intravenously to 10 patients with pulmonary mycosis (7 patients with primary pulmonary cryptococcosis and 3 with pulmonary aspergillosis). Routes of administration were changed in some patients depending on their condition. Two patients from whom foci was removed by surgical operations were excluded from the efficacy assessment. Clinical efficacies in the remaining 8 patients were good in 2 cases and fair in 3 cases of pulmonary cryptococcosis; excellent in 1 case of pneumonia due to Aspergillus; and fair in 1 case and poor in the other case of pulmonary aspergilloma. Side reactions developed in 9 patients who received intravenous drip infusion were nausea or loss of appetite in 3 patients, fever and/or feverish sensation in 3, vascular pain in 1 and diarrhea and eruption in 1. In the patient who reported fever the drug was discontinued and in the patient who complained of pain at the site of injection, dosing was changed to the oral route but was discontinued due to elevated GOT, GPT, Al-P and gamma-GTP. Seven patients who received the drug orally did not report side effects except 2 patients. None of these side effects reported was serious and from the above results, fluconazole was considered to be a useful agent for the treatment of pulmonary mycosis.

Administration, Oral↗
PubMed1989

[AE characteristics during compression test of high-copper amalgams and visible light-cured composite resins].

Differences in environmental strength of high-copper amalgams and photo-cured composite resins for posterior after storage in deionized water at 37 degrees C for 1 year were evaluated by examining compressive strength and acoustic emission (AE) characteristics. The results were as follows: Microfailure in amalgams and composite resins was detected from the onset of stress and their microfailures toward catastrophic failure occurred at 70 to 90% of their ultimate strength. One-year compressive strength for amalgam decreased to 80 to 98% of its 24-hour compressive strength and that for composite resin to 65 to 75%.

Composite Resins↗
PubMed1989

[Mediastinitis and left pyopneumothorax complicating a laryngeal phlegmon].

A case of mediastinitis and left pyopneumothorax complicating a laryngeal phlegmon caused by Candida albicans is described. A 64-year-old woman was admitted complaining of pharyngeal pain, hoarseness, dysphagia, and pain behind the left angle of the mandible. In that hospital, she was diagnosed as having a laryngeal phlegmon. She was known to be diabetic and hypertensive since 54 years of age. After admission, she became dyspneic, and chest X-rays revealed left atelectasis, left pleural effusion and left pneumothorax. After a drain was inserted into the left thoracic cavity, she was transferred to our hospital. Chest X-rays showed widening of the mediastinum, an enlarged cardiac shadow, mediastinal emphysema, left pneumothorax and bilateral pleural effusion. A thoracic CT also showed extensive mediastinal emphysema. On March 19, 1988 we incised the abscess behind the left angle of the mandible and inserted drains into both the mediastinum and left thoracic cavity under general anesthesia. Candidiasis was diagnosed based on culture of pus obtained from the abscess behind the left angle of the mandible. She was treated with antibiotics intravenously and through both drainage tubes for about 1 month. She was cured and discharged after 5 months of hospitalization.

Candidiasis↗
PubMed1989

[A case of giant leiomyoma of the esophagus].

A 34-year-old man was admitted to our hospital because of a tumor shadow in the posterior mediastinum. Leiomyoma of the esophagus was suggested by the findings of CT, esophagography, and esophagoscopy. He underwent thoracotomy. The operative procedure was enucleation of the tumor. The histological examination confirmed it to be a leiomyoma. The postoperative course was uneventful, and the passage of the esophagus was good. He was discharged 36 days after the operation.

Adult↗
PubMed1989

[An experimental study on surgical treatment of tracheomalacia-- methods for making models of tracheomalacia and development of a new operative method].

To develop a new surgical method for the repair of tracheobronchomalacia, we conducted experiments on dogs. First, we created malacic models by fracturing or resecting 5 to 10 tracheal cartilages. The bearing strength of the tracheal lumen became remarkably weakened, and bronchoscopic examination revealed tracheal collapses during coughing. Second, we tried external stenting of the malacic tracheae with prostheses. In 11 dogs, a prosthesis composed of Silastic sheet and Marlex mesh was sutured to the malacic segments of trachea. The connective tissue around the prosthesis increased in amount and the tracheal wall became firmer with time. However, mucosal defects around the sutures were found in 4 of the dogs. Those defects were probably due to injury to capillaries by the suturing procedures. Therefore, instead of suturing, we decided to try adhesives for fixation of the prosthesis to the trachea. We tested three adhesives: PUP (polyurethane-prepolymer), cyanoacrylate and fibrin glue. In five dogs using cyanoacrylate, the tracheal walls were remarkably hardened within 3 to 8 months. In eight dogs using fibrin glue for fixation of Marlex mesh to the malacic trachea the results were satisfactory. With fibrin glue, the tracheal walls after 3 to 8 months had almost the same strength as the average of normal tracheae.

Animals↗