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Biomedical subjects

M Satoyoshi

Publications and source records attributed to M Satoyoshi.

At least 19 recordsLinked to original sources

Extracellular processing of bone and dentin proteins in matrix mineralization.

There are two steps in the process of matrix-mediated bone and dentin mineralization. First, as in other soft tissues, osteoblasts/odontoblasts synthesize collagenous matrices and second, mineral deposits in these matrices at a location distant from the cells that synthesized the matrices. We suggest a sequence of events that lead the matrix to mineralization: the phosphoproteins of bone and dentin are posttranslationally processed by limited proteolysis, then they are extracellularly processed into a more phosphorylated species that, we believe, facilitates mineralization. Our in situ phosphorylation experiments done with [gamma-32P] GTP suggest the existence of extracellular phosphorylation by a casein kinase II (CKII)-like enzyme, the enzyme known to phosphorylate most of the phosphate residues in dentin phosphophoryn and bone sialoproteins (osteopontin and BSP II).

Adenosine Triphosphatases

Matrix mineralization and the differentiation of osteocyte-like cells in culture.

Osteocyte-like cells were prepared by sequentially treating calvaria from newborn rats with collagenase and chelating agents. On a reconstituted gel of basement membrane components, cells from the third collagenase digest displayed a round shape and expressed the highest level of alkaline phosphatase with minimal osteocalcin deposition into the matrix. On the other hand, cells derived from the interior after EDTA treatment exhibited well-developed dendritic cell processes and expressed essentially no alkaline phosphatase. The latter population also showed quite distinct characteristics such as higher extracellular activities of casein kinase II and ecto-5'-nucleotidase and the extracellular accumulation of a large amount of osteocalcin associated with mineral. These diverse phenotypic and protein expressions as well as the sites from which each population of cells were recovered strongly suggest that we have isolated osteoblastic and osteocytic cells. Bone sialoprotein II was extracellularly phosphorylated by casein kinase II in osteocytic cells but not in osteoblastic cells. We discuss the possibility that differentiation of young osteocytes from osteoblasts may facilitate the biochemical sequence of mineral deposition in the bone matrix.

5'-Nucleotidase

Extracellular processing of dentin matrix protein in the mineralizing odontoblast culture.

Odontoblasts that we prepared from bovine incisors produced a dentin-specific protein, phosphophoryn, and accumulated it in mineralized nodules. The time course of mineralization was detected by measuring osteocalcin and mineral in the nodules. The sequence of developmental expression of proteins in this mineralizing dentin cell culture is very similar to that in bone cells, suggesting a common mechanism for matrix mineralization in bone and dentin. Casein kinase II, which phosphorylates bone phosphoproteins and dentin phosphorylates bone phosphoproteins and dentin phosphophoryn, also emerges coinciding with the initiation of mineralization. Furthermore, we have detected extracellular phosphorylation by casein kinase II of a dentin protein of M(r) 60,000, which we recovered from the phosphophoryn fraction in CaCl2 precipitate.

Animals

Anaesthetic problems in a child with ectrodactyly, ectodermal dysplasia and cleft lip/palate. The EEC syndrome.

The EEC syndrome is a congenital anomaly complex associated with ectrodactyly, ectodermal dysplasia, and cleft lip and palate. We present a patient with the complete form of this syndrome who had undergone eight operations in childhood. The main problems encountered by the anaesthetists were malnutrition, difficulty with control of body temperature related to hypohidrosis and persistent infection of the respiratory tract.

Abnormalities, Multiple

Caudal anaesthesia for upper abdominal surgery in infants and children: a simple calculation of the volume of local anaesthetic.

Where the use of non-depolarizing muscle relaxants and antagonists is undesirable in infants and children undergoing abdominal surgery, caudal anaesthesia is frequently adopted, combined with light general anaesthesia. A simple calculation has been derived to determine the volume of local anaesthetic needed to obtain a higher effective anaesthetic level (up to T4-5) for upper abdominal operations using caudal anaesthesia. Clinically, a linear correlation was found between an empirically injected volume of local anaesthetic and the distance from C7 to the sacral hiatus in 21 infants and children. A similar relationship was also demonstrated radiographically in 16 cadavers by studying the spread of radio-opaque solution in the epidural space introduced by the caudal technique. From both statistical studies, a simple formula to determine the required volume of local anaesthetic for upper abdominal surgery was derived: V = D-13, where V is the volume of local anaesthetic in ml and D is the distance from C7 to the sacral hiatus in cm.

Abdomen