Efficient farnesylation of an extended C-terminal C(x)3X sequence motif expands the scope of the prenylated proteome.

Protein prenylation is a post-translational modification that has been most commonly associated with enabling protein trafficking to and interaction with cellular membranes. In this process, an isoprenoid group is attached to a cysteine near the C terminus of a substrate protein by protein farnesyltransferase (FTase) or protein geranylgeranyltransferase type I or II (GGTase-I and GGTase-II). FTase and GGTase-I have long been proposed to specifically recognize a four-amino acid CAAX C-terminal sequence within their substrates. Surprisingly, genetic screening reveals that yeast FTase can modify sequences longer than the canonical CAAX sequence, specifically C(x)3X sequences with four amino acids downstream of the cysteine. Biochemical and cell-based studies using both peptide and protein substrates reveal that mammalian FTase orthologs can also prenylate C(x)3X sequences. As the search to identify physiologically relevant C(x)3X proteins begins, this new prenylation motif nearly doubles the number of proteins within the yeast and human proteomes that can be explored as potential FTase substrates. This work expands our understanding of prenylation's impact within the proteome, establishes the biologically relevant reactivity possible with this new motif, and opens new frontiers in determining the impact of non-canonically prenylated proteins on cell function.

Comparative evaluation of calcium hypochlorite and sodium hypochlorite on soft-tissue dissolution.

INTRODUCTION: The aim of this study was to compare in vitro the tissue-dissolution properties of 5% and 10% calcium hypochlorite (Ca(OCl)(2)) with two concentrations (1.36% and 4.65%) of proprietary sodium hypochlorite (NaOCl) on bovine muscle tissue. METHODS: The available chlorine concentration of each solution was determined using iodometric titration. Tissue specimens from bovine muscle were weight adjusted (50 ± 5 mg). Ten tissue specimens in each group were immersed in 5 mL each test solution, removed after 5 minutes, blotted dry, and weighed. The process was repeated every 5 minutes with a fresh 5-mL aliquot of the test solution for 60 minutes or until complete tissue dissolution, whichever was quickest. The percentage weight loss of the specimens was calculated over the experimental period. RESULTS: Available chlorine concentrations of the irrigants ranged from 1.36% to 4.65%. All solutions dissolved tissue completely after 60 minutes except 5% Ca(OCl)(2) (99.4% dissolution). Between the 35- and 60-minute test readings, there were no significant differences between the solutions. Chlorax (4.65% NaOCl) (Cerkamed Group, Nisko, Poland) dissolved tissue quicker during the first 35 minutes (P < .05). In this period, the weight loss with 10% Ca(OCl)(2) differed from Chlorax at all time intervals except at 5 and 35 minutes (P < .05); 5% Ca(OCl)(2) showed no significant differences with 10% Ca(OCl)(2) and Tesco bleach (1.36% NaOCl) (Tesco Stores Ltd, Chestnut, UK) in the first 35 minutes except at the 5-minute measurement. CONCLUSIONS: Within the limitations of this study, Chlorax (4.65% NaOCl) dissolved tissue faster than the Ca(OCl)(2) solutions and Tesco thin bleach (1.36% NaOCl) over the first 35 minutes, but there were no significant differences among the solutions thereafter.

Dental dilemmas: Endodontics or dental implants?

UNLABELLED: This narrative review explores treatment planning options in restorative dentistry. The growth of dental implants, as an accessible and predictable treatment option, gives practitioners a useful tool for managing the missing tooth or teeth with a hopeless prognosis. Traditionally, endodontics and fixed prosthodontics have been used to restore teeth and spaces where the outlook for such treatment appears reasonable. Practitioners may, however, question the predictability and cost effectiveness of such an approach where, at times, it might appear that replacement of a compromised tooth with a dental implant could be a more predictable option. The evidence base for these treatment options is explored and discussed, and suggestions are made for future management strategies. CLINICAL RELEVANCE: A clear knowledge and understanding of the scientific literature for implants and endodontic treatment is necessary if practitioners are to make an evidence-based approach when treatment planning these modalities for their patients. This is particularly true in cases where there may appear to be a reasonable choice between the two of these.

Management of the compromised tooth.

Modern endodontic and restorative techniques allow some teeth previously thought to be unsaveable to be aesthetically restored to function. This paper discusses the use of such techniques and is illustrated with a case report.

In vitro evaluation of furcal perforation repair using mineral trioxide aggregate or resin modified glass lonomer cement with and without the use of the operating microscope.

This study evaluated in vitro the effect of using the operating microscope on repairing furcation perforations using Vitrebond or mineral trioxide aggregate. Forty-six human molar teeth were mounted into a jig attached to a simulated jaw. The teeth were allocated randomly to four groups (n = 10). Furcal perforations were made in the teeth using an ISO 012 round bur in a slow-speed hand-piece. Each material was used to repair a group of teeth with and without the use of the operating microscope. The remaining six teeth provided positive and negative controls. All groups were stored in 100% humidity, and the repair materials were allowed to set for 72 h at room temperature before being assessed for the quality of placement under x26 magnification. Leakage at the repair was then tested using India ink; the teeth were demineralized, dehydrated in alcohol, and rendered transparent in methyl salicylate. Dye penetration into the furcation repair was evaluated at x26 magnification. There was no difference in the acceptability of the repair with either material whether or not the operating microscope was used. The perforations repaired with mineral trioxide aggregate leaked significantly less to the tracer dye than those repaired with Vitrebond (p < 0.001).