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Biomedical subjects

J Lavigne

Publications and source records attributed to J Lavigne.

At least 19 recordsLinked to original sources

Nuclear matrix protein mitotin messenger RNA is expressed at constant levels during the cell cycle.

During the course of an investigation on nuclear matrix protein cDNAs, we have isolated a cDNA clone hybridizing with the messenger RNA encoding mitotin. Mitotin is a 125 kDa/pI 6.5 nuclear matrix protein present in proliferating but not in resting cells. This protein was shown to have a marked increase and characteristic redistribution in G2/M phase of the cell cycle. In this report, using synchronized Raji and WISH cells, we demonstrate that mitotin messenger RNA is expressed at the same level throughout the cell cycle.

Blotting, Northern

[Fixed partial denture on osseointegrated screw implants].

There are many differences between full dentures on Brånemark implants and fixed partial dentures built on the same type of implants: due to some more critical anatomical conditions, the choice of number, position and length of the implants is more delicate; the need of an harmonious crown-gingival tissue relationship; higher occlusal forces than in edentalous cases; difficulty in satisfying aesthetic requirements and ease of hygiene. The surgical treatment plan, a pre-requesite to any surgery, permits to determine the length of implants, their number, their position, their long axis direction and the design of the surgical guide, which will indicate to the surgeon the location and the axis for drilling. If this axis is nearly parallel to the sagittal plane for mandibular implants, it will be angulated to that same plane for maxillary implants. In the latter cases, it is often necessary to use angulated transepithelial abutments in order to prevent the abutment screw from having an occlusal access. In order to perform the prosthetis, an impression should be taken with the transepithelial abutments. The final reconstruction can be preceded by a temporary prosthesis, then (or) transitory to await gingival stabilization and not overload the implant immediately after it has been connected with the abutment. The fixed partial denture can be secured with screws or cemented when it is of small size and it must satisfy the functional and aesthetic requirements of the patient. The choice of the material used on the occlusal surface is very important and varies depending on the case. Aesthetics should not be prevent an in easy hygiene. These objectives are not reached at the time the prosthesis is made but during the course of the surgical and prosthetic treatment. Single restorations are subjected to the rules pertaining to any fixed partial denture on implants, but have particular characteristics, such as the almost systematic elimination of the abutment and the absolute necessity of the correct placement of the implant. The single units are more easily subject to unscrewing for mechanical reasons. Although the use of implants is a valuable aid in cases of partial fixed restoration, it requires particular attention with regard to precision.

Dental Implantation, Endosseous

Induction of beta 1-receptors for kinins in the rabbit by a bacterial lipopolysaccharide.

The intravenous injection of 10 microgram of a lipopolysaccharide extracted from E. Coli to rabbits leads to the appearance of a hypotensive effect for des-Arg9-BK and increases significantly the vasodilator effect of this peptide in isolated hearts and its contractile effects in strips of large arteries and veins. LPS elicits these responses when administered 5 or 20 h before anesthesia; the hypotensive response of animals receiving LPS just before anaesthesia is similar to that of untreated rabbits. All actions of des-Arg9-BK in vivo, in isolated hearts and in isolated tissues are blocked by des-Arg10,[Leu9]-kallidin (KD), a specific inhibitor of kinins B1-receptor. These data are taken as evidence of the appearance of B1-response to kinins in the few hours following LPS injection. The response of the animals, perfused organs and isolated tissues to other agonists, such as substance P or [Tyr(Me)8]-BK (an activator of B2-receptors for kinins) are not affected by the treatment with LPS nor are they modified by the antagonist des-Arg10,[Leu9]-KD. The present data, together with previous studies on the sensitization mechanism of B1-receptor containing preparations, suggest that LPS induces the formation of B1-receptors in the rabbit, within a few hours. The activation of B1-receptors by des-Arg9-BK produces hypotension, coronary vasodilation and stimulation of large arteries and veins isolated and suspended in vitro. Some large arteries and veins (e.g. the aorta and the anterior mesenteric vein) as well as some peripheral vascular beds (e.g. the coronary vessels) have the ability of generating B1-receptors, while other organs (e.g. the external jugular vein) have not or very little. The reason for this phenomenon as well as the intimate mechanism by which LPS induces the formation of B1-receptors remain to be elucidated.

Animals

[Presentation of a universal face-bow].

A universal face bow is reported for transferring an arbitary or located hinge axis on most articulators. Its use is simple and safe due to the rigidity of the assemblies during every step of the transfer.

Dental Articulators

[A new modular semi-adaptable articulator].

A new semi-adjustable Arcon articulator is reported. It is an evolutive device that can be set with two different types of condylar housings. - A Type: adjustable condylar guidance, preadjusted Bennett angle at 13 degrees - B Type: adjustable condylar guidance, adjustable Bennett angle. It is possible to set on this B type fossa assembly another Bennett wing with an adjustable immediate side shift This device has a double lock in centric relation and may be set with an arbitrary or localized hinge axis.

Dental Articulators

[The centric relation. IV. Variations in condylar positions according to the methods of measuring centric relation and to the patient's clinical type].

When recording and transferring centric relation onto an articulator errors can be minimized by proper use of dental materials. Remaining errors may be due to either the patient or the clinician. 3 recording techniques (Lucia, Dawson, Ramfjord) are being tested by 2 operators on 12 patients. In order to get a proper centric relation one must not rely upon a technique of taking it but rather on an adequate clinical evaluation of the TMJ at that moment. The role of inadequate intermaxillary relationship upon painful TMJ syndroms cannot be underestimate.

Adult

Specific inhibition of the incorporation of tritiated thymidine in regenerating rat liver by a rat hepatocytes supernatant.

Studies on endogenous inhibitors obtained from supernatant fluids of rat hepatocytes indicated that the supernatant arrests the normal cell cycle at two points, namely, before the beginning of the S phase and at the onset of metaphase when assayed in regenerating liver cells in situ. The specificity of this (these) inhibitory substance(s) was evidenced by the finding that no inhibition of cell division was observed in situ in tongue, intestine, or kidneys of animals injected with concentrations of the hepatocyte supernatant that inhibited cell division in regenerating liver. When higher concentrations of the inhibitor-containing supernatant were used, only the tongue epithelial cells were affected in addition to the regenerating liver cells.

Albumins

[The centric relation. I. Contribution to the study of the reliability of 3 materials for interocclusal registration].

Three materials commonly used for interocclusal registrations are tested under habitual conditions. The wax-type samples are softened in hot water to the optimal temperature, and then cooled off for hardening either in ice water, or room temperature water, or at room temperature air. These materials are stored for one month. Measurements are taken: - prior to any treatment - after hardening - after storage. The results are statistically analyzed. The least distorsion of material is obtained with the softer wax and vice versa. The room temperature air cooling has given best results. Time does not seem to modify measurements made on heat treated materials which may be accurately stored at room temperature.

Dental Impression Materials

[The Centric relation. II. Volumetric variations during the mounting of models on the articulator].

When mounting models on the articulator there is some possibility of error due to the expansion of plaster during the setting period. If one does not pay attention to this expansion, one can observe an opening in between the arms of the articulator. In order to minimize expansion one must: -- increase the W/P ratio -- decrease the amount of plaster used for mounting the models The expansion modifies the reference plane and this is important only in case of remountings.

Dental Materials