The interaction of calmodulin with purified guinea pig liver transglutaminase was studied. The nucleotide (ATP and GTP) hydrolysis activity of this tissue transglutaminase was transiently increased and then gradually decreased depending on calmodulin concentration. The peak activation was obtained in the presence of a stoichiometric amount of calmodulin. The effect of calmodulin on the classical transglutaminase activity was minimal. Fluorescence spectroscopy demonstrated that the enzyme produced a significant blue shift in the emission peak of dansylated calmodulin. Interestingly, Ca2+ was not required for the interaction between the two proteins. The results described here give an additional regulatory role to calmodulin.

Adenosine Triphosphate↗

PubMedDate not supplied

Maxillary and mandibular titanium implants 1 year after surgery: histologic examination in a cadaver.

Nondecalcified histologic sections (from a cadaver) of 12 IMTEC implants in four jaw quadrants 1 year after surgery showed significant osseointegration. Microscopically, no apparent difference was observed in new bone growth and osseointegration in those implants placed in the maxilla or mandible, or between titanium plasma-spray-coated (TPS) implants and TPS-treated implants coated with hydroxyapatite. Areas in which implants were placed through the bony floor of the maxillary sinus showed new bone growth above the normal level of the floor of the sinus around the implants and into mechanical retention holes. Small penetrations of the maxillary sinus membrane or the lingual plate of the mandible did not affect the function of the implants, nor did they cause any symptoms. A vertical component of soft tissue around the cervical part of the osseointegrated implants, noted in histologic sections to be as much as 5 mm below the crest of the alveolar bone in at least one area, was not discernible radiographically even when 5-mm-thick sections of bone containing the implants were radiographed.

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