[The effect of composition on the mechanical properties of composite resin]

The objective of this investigation was to determine whether the composition of composite resin affects the amount of residual monomers and the strength of resin. Six types of resin composition were designed and 30 composite resin specimens were made in glass mold of 6mm diameter and 3mm height. The residual monomer of each specimen was extracted by 10cc ethanol solution for 1, 2, and 3 days of experiment. UV/Vis spectrophotometer was used to estimate the amount of residual monomer of the specimen, and universal testing machine was used to test the diametral tensile strength of the composite resin. The results were as follow; 1. Composite resins of 1% benzoyl peroxide concentration released the higher level of residual monomers than the resin of 0.8% benzoyl peroxide concentration. 2. t-Butylaminoethylmethacrylate.HF of 17% concentration exhibited the greater level of residual monomer than the other resin monomers. 3. As the concentration of the trimethylolpropane trimethacrylate increased, the amount of Bis-GMA residual monomer increased. 4. Composite resin of 1% benzoyl peroxide concentration showed higher tensile strength than the resin of 0.8% benzoyl peroxide concentration. 5. As the concentration of trimethylolpropane trimethacrylate increased above 50%, the strength of the composite resin decreased.

Phase II study of cyclophosphamide, doxorubicin, and vincristine (CAV) and etoposide plus cisplatin (EP) alternating chemotherapy combined with radiotherapy in small cell lung cancer

The development of drug resistance is the major limiting factor influencing the survival of patients with small cell lung cancer (SCLC). We have thus examined the activity of cyclophosphamide, doxorubicin and vincristine (CAV) alternating with etoposide and cisplatin (EP) in 35 patients with SCLC. The treatment courses were alternated every 3 or 4 weeks. After induction chemotherapy, patients with limited disease (LD) received thoracic radiotherapy (5000 cGy), prophylactic cranial irradiation (3000 cGy) and maintenance chemotherapy and patients with extensive disease (ED) received maintenance chemotherapy only. In this group of 35 patients, 13 had limited disease (LD) and 22 had extensive disease (ED). After completion of the therapy, 100% of the patients with LD achieved complete plus partial remission (CR + PR) and 68% of the patients with ED achieved CR + PR. The median survival time was 66 weeks (15.3 months) in patients with LD and 44 weeks (10.2 months) in patients with ED. The over all survival for patients with LD was superior to that for patients with ED (p less than 0.05). Also, median response duration for patients with LD (35 wks) was longer than that for patients with ED (17 weeks) (p less than 0.05). The primary site was the most vulnerable site to relapse (18 patients). Toxicity was mild to moderate and acceptable, and there were no treatment-related deaths. These results suggest that the alternation of CAV and EP is effective treatment strategy in the management of SCLC. A randomized controlled study will be required to discriminate the actual effect of this alternating regimen.

Current status and future aspects on treatment of liver cancer

Among 80 patients with advanced hepatocellular carcinoma, treated by systemic chemotherapy, 19 patients (24%) achieved partial response or stable disease. The median survival time of responders was 20 weeks. Radioiodinated fatty acid esters ([131I]lipiodol) are localized in hepatoma tissue for a considerable time. Taking advantage this phenomenon, there is a potential therapeutic effect of [131I]lipiodol, since the radioactive oil can deliver a therapeutic dose of internal radiation. The response rate of patients who had a small hepatoma (less than 5 cm in diameter) was 80%. Among 25 responders, 12 cases are alive after more than 1 year. A pilot study of hyperthermia, using a heating device capable of delivering radiofrequencies, combined with radiotherapy or chemotherapy, demonstrated that this modality is safe and effective in the treatment of advanced hepatocellular carcinoma. Of the 19 patients treated, 47% showed partial remission or stable disease. The median survival time of 9 responders was 9 months. Among the 9 responders 3 patients survived for over 1 year.

Laryngeal pacemaker using a temperature sensor in the canine

With the use of a temperature sensor that would detect temperature changes during the respiratory cycle in the pharynx, electrical stimulation of the posterior cricoarytenoid muscle was achieved in dogs whose recurrent laryngeal nerves were artificially paralyzed. Due to the temperature difference between inspiratory and expiratory air flow, a trigger pulse was generated at the beginning of inspiration. The stimulation pulse following the trigger pulse stimulated the electrodes inserted into the posterior cricoarytenoid muscles. In all five canines, obvious abduction of the vocal folds synchronized with inspiration was observed during electrical pacing.

The clinical and thyroid function studies of lymphocytic thyroiditis with spontaneously resolving hyperthyroidism: comparison to subacute thyroiditis

Lymphocytic thyroiditis with spontaneously resolving hyperthyroidism (LT-SRH) has been reported in the past years, and is referred to as “silent thyroiditis.” It is characterized by a low or decreased radioactive iodine uptake (RAIU) of thyroid in a patient with hyperthyroidism in whom initial diagnosis is generally thought to be Graves’ disease. Thirty-five patients who had hyperthyroidism or goiter with decreased RAIU have been assessed. Twenty-four (68.6%) of 35 patients had LT-SRH and the remaining patients, subacute thyroiditis (SAT). The clinical characteristics of the patients with LT-SRH were a history of delivery, painless goiter, elevated T3 and T4 levels and positive anti-microsomal antibodies. Anti-microsomal antibodies were positive in 70.8% of the LT-SRH group, whereas 12.5% in the SAT group. Resolution of the hyperthyroidism took 8 to 12 months. It is considered that LT-SRH is an autoimmune thyroiditis with spontaneously resolving hyperthyroidism and determination of the RAIU is very useful in differentiating from other forms of hyperthyroidism.