Elkhadem, A., and P. Nagi, "Effectiveness of MTA pulpotomy in primary molars: a critical assessment of relevant studies.", Evidence-based dentistry, vol. 14, issue 2, pp. 46, 2013. Abstract


STUDY SELECTION: Studies that evaluated the efficacy of MTA as a pulpotomy medicament in primary teeth were included, abstracts, observational studies and case reports were excluded. Only English language studies were considered.

DATA EXTRACTION AND SYNTHESIS: Studies were assessed and graded by two reviewers using a weighted criteria based system and a qualitative summary of the evidence provided.

RESULTS: Twenty-two studies were included, 17 studies compared MTA with formocresol, four studies compared MTA with calcium hydroxide, ferric sulphate, Portland cement, calcium-enriched mixture cement (CEM) and one study compared white MTA with grey MTA.

CONCLUSIONS: Based on the assessment criteria employed, there was no evidence that MTA was better than present materials and techniques as a pulpotomy medicament.

Buchet, R., L. Beauvais, and C. Sandorfy, "Hydrogen bond equilibrium constants of some unusual nucleotide base pairs.", Journal of biomolecular structure & dynamics, vol. 2, issue 1, pp. 221-32, 1984 Aug. Abstract

Approximate hydrogen bond association constants were determined for base pairs formed by an adenine derivative and a number of unusual pyrimidine bases. A series is found in which the H-bond strength in the base-pairs varies. In certain cases the H-bond equilibrium constant is larger than in the adenine-thymine pair. Inosine derivatives seem to have a non-negligible chance of replacing guanosine in the guanosine-cytosine pair. Infrared, near-infrared (overtone) and NMR spectra were used to determine the equilibrium constants.

Baccanari, D., A. Phillips, S. Smith, D. Sinski, and J. Burchall, "Purification and properties of Escherichia coli dihydrofolate reductase.", Biochemistry, vol. 14, issue 24, pp. 5267-73, 1975 Dec 2. Abstract

Dihydrofolate reductase has been purified 40-fold to apparent homogeneity from a trimethoprim-resistant strain of Escherichia coli (RT 500) using a procedure that includes methotrexate affinity column chromatography. Determinations of the molecular weight of the enzyme based on its amino acid composition, sedimentation velocity, and sodium dodecyl sulfate gel electrophoresis gave values of 17680, 17470 and 18300, respectively. An aggregated form of the enzyme with a low specific activity can be separated from the monomer by gel filtration; treatment of the aggregate with mercaptoethanol or dithiothreitol results in an increase in enzymic activity and a regeneration of the monomer. Also, multiple molecular forms of the monomer have been detected by polyacrylamide gel electrophoresis. The unresolved enzyme exhibits two pH optima (pH 4.5 and pH 7.0) with dihydrofolate as a substrate. Highest activities are observed in buffers containing large organic cations. In 100 mM imidazolium chloride (pH 7), the specific activity is 47 mumol of dihydrofolate reduced per min per mg at 30 degrees. Folic acid also serves as a substrate with a single pH optimum of pH 4.5. At this pH the Km for folate is 16 muM, and the Vmax is 1/1000 of the rate observed with dihydrofolate as the substrate. Monovalent cations (Na+, K+, Rb+, and Cs+) inhibit dihydrofolate reductase; at a given ionic strength the degree of inhibition is a function of the ionic radius of the cation. Divalent cations are more potent inhibitors; the I50 of BaCl2 is 250 muM, as compared to 125 mM for KCl. Anions neither inhibit nor activate the enzyme.

Marniemi, J., and M. G. Parkki, "Radiochemical assay of glutathione S-epoxide transferase and its enhancement by phenobarbital in rat liver in vivo.", Biochemical pharmacology, vol. 24, issue 17, pp. 1569-72, 1975 Sep 1. Abstract
Elkhadem, A., and N. Orabi, "Weak evidence suggests higher risk for bracket bonding failure with self-etch primer compared to conventional acid etch over 12 months.", Evidence-based dentistry, vol. 14, issue 2, pp. 52-3, 2013. Abstract

DATA SOURCES: Medline, Embase, Cochrane Oral Health Group's Trials Register and the Cochrane Central Register of Controlled Trials (CENTRAL). Unpublished data were sought by searching ClinicalTrials.gov, the National Research Register and Pro-Quest Dissertation Abstracts and Thesis database. There were no language restrictions.

STUDY SELECTION: Randomised and controlled clinical trials (including split mouth) directly comparing self-etch and acid-etch primers including patients with full-arch, fixed and bonded orthodontic appliances (not banded) with follow-up periods of at least 12 months were included.

DATA EXTRACTION AND SYNTHESIS: Two authors abstracted data independently, with disagreements being resolved by a third. The Cochrane Risk of Bias tool was used to assess study quality. A random effects meta-analysis was undertaken.

RESULTS: Eleven studies were included in the qualitative summary with five studies contributing to a meta-analysis. These five studies (n =3444 brackets, 1721 acid-etch, 1723 self-etch) had relatively low statistical and clinical heterogeneity. Meta-analysis demonstrated a tendency for a higher risk of failure (odds ratio 1.35; 95% CI, 0.99-1.83; P 5 0.06) with self-etch primers. The use of self-etch techniques was also associated with a small but statistically significant time saving (weighted mean difference 23.2 seconds per bracket; 95% CI, 20.7-25.8; P \0.001). There was insufficient evidence to assess the effect of bonding modality on demineralisation rates.

CONCLUSIONS: There is weak evidence indicating higher odds of failure with self-etch primer than acid-etch over 12 months in orthodontic patients, and there is strong evidence that a self-etch primer is likely to result in modest time savings (eight minutes for full bonding) compared with acid-etch.

Fahnestock, S. R., "Evidence of the involvement of a 50S ribosomal protein in several active sites.", Biochemistry, vol. 14, issue 24, pp. 5321-7, 1975 Dec 2. Abstract

The functional role of the Bacillus stearothermophilus 50S ribosomal protein B-L3 (probably homologous to the Escherichia coli protein L2) was examined by chemical modification. The complex [B-L3-23S RNA] was photooxidized in the presence of rose bengal and the modified protein incorporated by reconstitution into 50S ribosomal subunits containing all other unmodified components. Particles containing photooxidized B-L3 are defective in several functional assays, including (1) poly(U)-directed poly(Phe) synthesis, (2) peptidyltransferase activity, (3) ability to associate with a [30S-poly(U)-Phe-tRNA] complex, and (4) binding of elongation factor G and GTP. The rates of loss of the partial functional activities during photooxidation of B-L3 indicate that at least two independent inactivating events are occurring, a faster one, involving oxidation of one or more histidine residues, affecting peptidyltransferase and subunit association activities and a slower one affecting EF-G binding. Therefore the protein B-L3 has one or more histidine residues which are essential for peptidyltransferase and subunit association, and another residue which is essential for EF-G-GTP binding. B-L3 may be the ribosomal peptidyltransferase protein, or a part of the active site, and may contribute functional groups to the other active sites as well.

Moroi, K., and T. Sato, "Comparison between procaine and isocarboxazid metabolism in vitro by a liver microsomal amidase-esterase.", Biochemical pharmacology, vol. 24, issue 16, pp. 1517-21, 1975 Aug 15. Abstract
Elkhadem, A., and P. Nagi, "No evidence for effectiveness of interventions used to treat displaced permanent anterior teeth.", Evidence-based dentistry, vol. 14, issue 3, pp. 83, 2013 Sep. Abstract

DATA SOURCES: The Cochrane Oral Health Group Trials register, Cochrane Central Register of Controlled trials (CENTRAL), Medline, Embase, LILACS and Dissertation, Theses and Abstracts databases.

STUDY SELECTION: Randomised controlled trials or quasi-randomised controlled trials that included a minimum follow-up period of 12 months.Data extraction and synthesisTwo review authors independently and in duplicate assessed the eligibility of all reports identified in the searches. Authors were contacted for additional information where required.

RESULTS: No randomised or quasi-randomised controlled trials were found.

CONCLUSIONS: We found no randomised or quasi-randomised trials of interventions to treat displaced luxated permanent front teeth. Current clinical guidelines are based on available information from case series studies and expert opinions. Randomised controlled trials in this area of dental trauma are required to robustly identify the benefits of different treatment strategies.

Konjhodzić, F., "[Spinal echinococcosis].", Medicinski arhiv, vol. 38, issue 3, pp. 101-3, 1984. Abstract
Asakura, T., K. Adachi, M. Shapiro, S. Friedman, and E. Schwartz, "Mechanical precipitation of hemoglobin köln.", Biochimica et biophysica acta, vol. 412, issue 2, pp. 197-201, 1975 Dec 15. Abstract

Hb Köln (beta 98 Val leads to Met) was found to precipitate rapidly during mechanical shaking. The rate of precipitation of Hb Köln is 5-6 times faster than that of Hb S. The kinetics of precipitation of the patient's hemolysate, which is a mixture of Hb Köln and Hb A, showed a biphasic curve indicating that Hb Köln precipitates independently from Hb A. The instability of Hb Köln may be attributed to the conformational change in the vicinity of heme. The mechanical shaking may be used as a new method for detection and quantitation of hemoglobin Köln and other unstable hemoglobins.