Multidisciplinary implant dentistry for improved aesthetics and function.

Functional and aesthetic restorations that involve implant-supported prostheses rely on the efforts of a multidisciplinary team composed of surgeon, prosthodontist, and laboratory technician. The team must examine the anticipated restorative site to determine the suitability of existing hard and soft tissues for implant placement. When the site requires osseous or gingival augmentation, the team must select the appropriate means of restoration from the armamentarium. This article describes chronologically the various parameters that must be considered by each member of the team as the treatment proceeds.

Asymptomatic carriers of Babesia canis in an enzootic area. / Etude du portage asymptomatique de Babesia canis en zone d'enzootie.

Dogs latently infected with Babesia canis were systematically detected amongst a population kept in an enzootic area over a year. Detection of parasite was carried out on 43 healthy dogs and identified by two blood cultures in an interval of a few months. A serological study was performed using indirect immunofluorescence and Western blot. This study distinguished two distinct groups: asymptomatic carrier dogs (latently infected or premunised-33%) and non-carrier dogs with sterilising immunity. There is no difference between carrier and non-carrier dogs concerning age, breed or history of babesial infection and 36 out of the 43 dogs studied are seropositive. The antibody titer did not completely correlate with the detection of parasitaemia. All carrier dogs are seropositive to Babesia canis, but half of the seropositive dogs are not carriers. This study confirms that serological detection is not a good indicator of latent babesial infection. This study did not detect any difference between antibody responses (quantitative response (IIF) or qualitative response (WB)), related to latent parasitaemia.

Immunolocalization and characterization of the low molecular weight antigen (4-5 kDa) of Toxoplasma gondii that elicits an early IgM response upon primary infection.

A striking feature of toxoplasmic seroconversion is the prominent and early IgM response to a low molecular weight antigen of 4-5 kDa. Two different monoclonal antibodies directed against the 4-5 kDa antigen have been generated and used to characterize this molecule. Using these monoclonal antibodies, we could demonstrate the surface localization of the low M(r) antigen by immunofluorescence and immuno-electron microscopy assays. By immunoblotting, we observed that one of the monoclonal antibodies was unable to recognize the 4-5 kDa antigen in tachyzoites propagated in cell culture, indicating an epitope variability between Toxoplasma gondii tachyzoites grown in vivo and in vitro. We discuss the implications of this latter finding in the design of diagnostic reagents.

Differential targeting of dense granule proteins in the parasitophorous vacuole of Toxoplasma gondii.

The biosynthesis and fate of 4 different dense granule proteins of Toxoplasma gondii were studied with 3 monoclonal antibodies raised against tachyzoites and 1 polyclonal antibody raised against a recombinant protein. These proteins have the following molecular weights: 27 kDa (GRA 1), 28 kDa (GRA 2), 30 kDa (GRA 3) and 40 kDa (GRA 4). All four proteins were found in dense granules by immunoelectron microscopy; in T. gondii-infected cells, they were found in the vacuolar network but, in addition, GRA 3 was also detected on the parasitophorous vacuole membrane. Therefore, dense granule contents undergo differential targeting when exocytosed in the parasitophorous vacuole. Metabolic labelling and immunoprecipitation showed that GRA 2 and GRA 3 were processed from lower molecular weight precursors, and that GRA 2 and GRA 4 incorporated [3H] glucosamine and are thus likely to be glycosylated.

Characterization of the lipid content of Toxoplasma gondii rhoptries.

Quantitative and qualitative analysis of lipids has been performed on a rhoptry fraction purified from Toxoplasma gondii tachyzoites. The lipid to protein ratio was estimated to be 0.26. The cholesterol to phospholipid ratio was unusually high at 1.48. Phosphatidylcholine was the major phospholipid; phosphatidylserine, phosphatidylinositol and sphingomyelin were absent whereas significant amounts of phosphatidic acid and lysophospholipids were found. This pelicular composition could be related to functional involvement of the organelle in host-cell invasion.

Characterization of the protein contents of rhoptries and dense granules of Toxoplasma gondii tachyzoites by subcellular fractionation and monoclonal antibodies.

A subcellular fractionation procedure has been established to isolate the rhoptries of Toxoplasma gondii tachyzoites on a self-generating Percoll gradient. The rhoptry fraction also contains dense granules. Monoclonal antibodies have been raised against the fraction and used to identify major proteins in the organelles by immunoelectron microscopy and Western blotting. Six major rhoptry proteins (60.5 kDa, Pi 5.8; 55, 57, 59, 60 kDa, all of Pi over 8; 42 kDa, Pi 4.8) and 3 dense granule proteins (30 kDa; 28kDa, Pi 7.5; 27 kDa, Pi 4.5) together with 5 other proteins of 57, 90, 120, 168, 220 kDa that have been located in the rhoptry area by indirect immunofluorescence have been identified.

Exocytosis of Toxoplasma gondii dense granules into the parasitophorous vacuole after host cell invasion.

Tachyzoites of Toxoplasma gondii have been shown to exocytose the contents of dense granules into the parasitophorous vacuole after host cell invasion. A monoclonal antibody specific for a 27-kDa protein was used to locate the dense granules by immunoelectron microscopy. The same antibody also reacted with the tubular network found in the parasitophorous vacuole, which confirmed that the dense granules were exocytosed by tachyzoites.