Purification, partial sequencing and characterization of an insect membrane dipeptidyl aminopeptidase that degrades the insect neuropeptide proctolin.

Two proctolin-binding proteins solubilized from 1600 cockroach hindgut membranes were purified 1000-fold using five chromatography steps. Twenty-five micrograms of protein were recovered from the final size-exclusion chromatography as a single peak eluting at 74 kDa, whereas two major bands at 80 and 76 kDa were identified after silver staining of electrophoresis gels. The fragments, sequenced by tandem mass spectrometry and the Edman method, revealed a high homology with rat liver dipeptidyl aminopeptidase (DPP) III and a significant homology between the cockroach-purified proteins. From analysis of the Drosophila genome sequence database, it was possible to identify a putative DPP sharing high homology with the sequences obtained from the cockroach purified proteins and with the rat DPP III. Anti-(rat liver DPP III) Ig reacted specifically with both cockroach-purified proteins in Western blot analysis. The purified proteins removed the N-terminal dipeptide from the insect myotropic neuropeptide proctolin (Arg-Tyr-Leu-Pro-Thr) with a Km value of 3.8 +/- 1.1 microM. The specific DPP III inhibitor tynorphin prevented the degradation of proctolin by the purified insect DPP (IC50 = 0.68 microM). These results provide strong evidence that the cockroach-purified proteins represent an insect membrane DPP, presumably present in Drosophila, and that it is closely related to vertebrate DPP III.

Maxillary sinus floor augmentation using bioactive glass granules and autogenous bone with simultaneous implant placement. Clinical and histological findings.

This clinical study was undertaken to: 1) evaluate the use of bioactive glass Biogran combined with autogenous bone as grafting material for maxillary sinus augmentation with simultaneous implant placement using radiography and histology; and 2) document the short-term post-loading success of implants inserted in sinus cavities augmented with this material. Unilateral or bilateral sinus augmentation was performed in 12 patients with 3-5 mm of alveolar crestal bone height in the posterior maxilla prior to grafting. The sinuses were grafted with bioactive glass mixed in a 4:1 ratio with autogenous bone. Simultaneously, 2-3 threaded titanium implants were inserted into the augmented sinuses. Second stage surgery was carried out 9 to 12 months post implantation. At abutment connection, 10 core biopsy specimens were taken from different grafted sites and evaluated histologically. All 27 implants were clinically stable at second stage surgery. A mean increase in mineralized tissue height of 7.1 +/- 1.6 mm was evident when comparing the pre-surgical CT scans with those performed 9-12 months following the sinus augmentation procedure. Evaluation of the cores yielded a mean of 30.6 +/- 5.7% of bone tissue in the grafted sites. One implant failed during the prosthetic phase while the remaining 26 implants were stable 12 months post loading. This study suggests that Biogran/autogenous bone graft combination used in one-stage sinus augmentation yields sufficient quality and volume of mineralized tissue for predictable simultaneous implant placement in patients with 3-5 mm of bone height prior to grafting.

Purification of proctolin-binding proteins from the foregut of the insect Blaberus craniifer.

A membrane protein that specifically binds the insect neuropeptide proctolin was purified using standard chromatography from cockroach foregut membranes. Proctolin-binding sites were efficiently solubilized with either the nonionic detergent digitonin or the zwitterionic detergent Chaps, as indicated by the specific binding of 3H-proctolin to solubilized samples. A solubilized sample obtained from 1600 foregut membranes was subjected to a five-step chromatographic purification including chromatofocusing, anion-exchange and size-exclusion chromatographies. The final size-exclusion separation resulted in the isolation of approximately 100 pmol of purified proctolin-binding proteins, eluting as a single peak at approximately 74 kDa. Analysis of the purified sample using SDS/PAGE and silver staining showed two bands at 80 kDa and 76 kDa. Densitometric analysis of the gel indicated that each band contained approximately 7-8 microg of protein, suggesting that one band corresponds to the proctolin-binding activity. Proctolin-binding proteins were thus purified 1800-fold using standard chromatography.

Clinical and radiographic findings following placement of single-tooth implants in young patients--case reports.

Single-tooth implants were inserted in the maxillary anterior segments of three young patients aged 11.5 to 13 years. The patients were monitored for a period of 2.5 to 4.5 years. All implant-supported crowns ended up in an infraocclusion position relative to the adjacent teeth because of the continued vertical growth of the maxillary alveolar process. Between base-line examination and the date of recall, the distance from a fixed reference point located on the fixture to the crestal bone on the proximal surfaces of teeth adjacent to the implant sites increased up to 3 mm. Transverse growth changes were also observed. Although the prostheses could be removed and modified to compensate for the resulting soft and hard tissue changes, complications may occur altering the health of the mucogingival unit and the esthetic appearance of implant-supported restorations, and requiring further soft tissue correction procedures.