Biomedical subjects
Publications and source records attributed to F Kubo.
Four families with hyperproinsulinemia found in Japan were described. The details of the first case, who was investigated by Kanazawa et al., were reported and the similarity of the first case to the following cases was shown. Arginine 65 of the proinsulin molecule might be a hot spot of the insulin gene. A possible abnormality of insulin release in affected individuals was disclosed by investigation of the family members of the first case.
A case of thoracic empyema after artificial pneumothorax for lung tuberculosis was presented, which extended into the abdominal cavity. 65 years old man, who was operated on for lung tuberculosis about 30 years ago, took the routine physical examination and the abdominal mass was picked up on examination. Echogram and CT showed huge homogeneous mass in the right thorax and the right upper abdominal cavity. The operative finding showed that thoracic empyema extended into the abdominal cavity and formed a huge mass. Decortication and extirpation of thoracic empyema and abdominal mass was performed with a combined partial resection of the lung, diaphragma, and thoracic wall. The histopathology of the abdominal mass showed chronic empyema and hematoma.
Self-setting apatite cement hardens into a mass of single phase apatite when mixed with diluted phosphoric acid. Structurally this mass consists of two types of apatite, i.e. the seed apatite used as a setting accelerator and the matrix apatite formed afterward in the reaction of dicalcium phosphate dihydrate (DCPD) and tetracalcium phosphate (Te-CP). To investigate the dissolution behavior of self-setting apatite cement in detail, two types of 45Ca labeled apatite cement were prepared. In one, the seed apatite was labeled with 45Ca (45Ca-HAp cement) and in the other the matrix apatite was labeled with 45Ca through use of 45Ca-DCPD (45Ca-DCPD cement). Solubility, estimated from the concentration of 45Ca released in 1 mM of organic acid (e.q. acetic, lactic, or citric acid) with initial pH adjusted to 4.0 at 37 degrees C, was approximately zero for 45Ca-HAp cement, whereas the solubility of 45Ca-DCPD cement was approximately the same as unlabeled cements used so far. This finding suggests that dissolution of the matrix apatite governs dissolution of the set cement, though comparison of X-ray diffraction patterns and electron micrographs of the seed apatite and apatite in the set cement showed no essential difference in crystallinity and crystal shape. The fact that the matrix apatite was formed by enveloping the seed apatite may account for the preferential dissolution of matrix apatite. In synthetic saliva labeled with 45Ca having a degree of supersaturation with respect to apatite comparable to rest saliva, 45Ca concentration in solution decreased once the cement pellet was introduced.(ABSTRACT TRUNCATED AT 250 WORDS)
Addition of barium hydroxyapatite (BaAp) successfully bestowed clinically acceptable radioopacity to the self-setting apatite cement consisting of an equimolar mixture of tetracalcium phosphate and dicalcium phosphate dihydrate. To accelerate the setting reaction which was retarded by Ba2+ released from BaAp at a lower pH during first stage of spatulation with 20 mM phosphoric acid, calcium hydroxyapatite (CaAp) was added to the cement mixture. At about 20 wt% of BaAp and 20 wt% CaAp, the setting reaction proceeded at a neutral or weak alkaline pH, which is one of the most promising aspects of the self-setting cement and assures that this type of cement may be the least irritating of the dental cements presently available. The cement spatulated at L/P = 0.4 set within 10 minutes and its radiopacity was comparable to or more than that of tooth enamel. The wet compressive strength of the set cement stored for one day in synthetic saliva at 37 degrees C was approximately 100 kgf/cm2. Although this value is almost one fourth that of 40 wt% CaAp cement, this cement appears to be strong enough to apply as root canal filling material.
Twenty experimental phosphate-bonded investments were prepared by the mixing of two types of fillers (spherical glass beads and irregularly shaped silica particles) with five types of filler aggregates of different porosities, and two different ratios of MgO to NH4H2PO4. These investments were mixed with three different liquids, and their setting expansion, time until setting expansion began (induction time), and fluidity were measured under constant experimental conditions. The following results were obtained: (1) The setting expansion was significantly related to bulk porosity of filler aggregates, not to packed porosity, despite variations in type of filler, ratio of MgO to NH4H2PO4 or type of liquid; and (2) the fluidity and the time until setting expansion began were also related to the bulk porosity of the filler aggregates.
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