Dental abnormalities after pediatric bone marrow transplantation.

Our purpose was to describe the types and frequencies of altered dental development in pediatric patients following bone marrow transplantation (BMT). A retrospective review of the medical records and panoramic radiographs of all patients who underwent BMT at St Jude Children's Research Hospital between 1990 and 2000, for whom pre-BMT and post-BMT dental examination and panoramic radiography records were available, is presented. All patients were treated on institutional protocols. We recorded patient demographics and radiographic evidence of microdontia, hypodontia, taurodontia, root stunting, caries, enamel pearls, dental restorations/extractions and pulpal calcification. The 99 patients identified (52 males, 47 females) had a median age of 13.5 years (range, 3.4-25.9 years) at the time of BMT. In all, 73 were Caucasian, 15 were African-American, and 11 were of other races. The frequency of radiographically evident root stunting in permanent teeth was significantly increased after BMT (P<0.001), but there was no significant change in the frequency of other dental abnormalities after BMT. Dental abnormalities are prevalent in survivors of childhood BMT, but only root stunting appeared to progress with BMT.

Dental abnormalities in children preparing for pediatric bone marrow transplantation.

The purpose of our study was to describe the types and frequencies of altered dental development in pediatric patients preparing for bone marrow transplantation (BMT). Retrospective review of the medical records and panoramic radiographs of all patients who underwent BMT at St Jude Children's Research Hospital between 1990 and 2000 for whom pre-BMT dental examination and panoramic radiography records were available. All patients were treated on institutional protocols. We recorded patient demographics and radiographic evidence of microdontia, hypodontia, taurodontia, root stunting, caries, enamel pearls, and pulpal calcifications. The 259 patients identified (150 male and 109 female) had a median age of 12.82 years (range, 3.18-25.93 years) at the time of BMT. In total, 203 were Caucasian, 38 were African-American, and 18 were of other races. In all, 150 (57.9%) had abnormal dentition. The most common dental abnormalities were caries (n=84), pulpal calcifications (n = 34), and dental extractions (n = 33). Developmental abnormalities occurred less frequently: taurodontia (n = 8), hypodontia (n = 10), microdontia (n = 11), and root stunting (n = 11). Dental abnormalities are prevalent in children undergoing BMT. Pre-transplant oral hygiene and dental examination should be standard care in order to minimize potential sites of infection.

Investigation of bioisosteric effects on the interaction of substrates/ inhibitors with the methionyl-tRNA synthetase from Escherichia coli.

Aminoacyl-tRNA synthetases catalyze the stepwise coupling of specific amino acid substrates to their cognate tRNAs. The first intermediate formed in this process is the aminoacyl-adenylate, which then subsequently reacts with the 3'-terminus of the cognate tRNA to transfer the amino acid to the tRNA. This overall reaction is critical for protein biosynthesis and is quintessential to the viability of all organisms. Therefore, the selective inhibition of bacterial amino acid-tRNA synthetases is the focus of intense current interest for the development of novel antibacterial agents. In order to elucidate some of the critical factors involved in recognition and binding of potential inhibitors to these bacterial systems, the current report has focused on the methionyl-tRNA synthetase from Escherichia coli. This enzyme has been studied with two sets of bioisosteric replacements in the methionine and methionyl-adenylate structures. Replacements of the carboxyl group of methionine with the phosphinic and phosphonic acid moieties were used to probe the effects of including potential transition state analogs on enzyme inhibition. The contributions of the aminoacyl-adenylate structure and the effect that fluorination has on inhibitory activity were investigated utilizing 5'-O-[(L-methionyl)-sulfamoyl]adenosine and 5'-O-[(S-trifluoromethyl-L-homocysteinyl)-sulfamoyl]adenosine. The K(i) values for these compounds were determined to be 0.4 mM, 1.2 mM, 0.25 nM and 2.4 nM respectively. A discussion of this data in relation to structural information provided by the recent determination of the three-dimensional structures of the E. coli enzyme with several of these compounds is presented.

Deciduous tooth size standards for American blacks.

Normative standards for tooth sizes are valuable for assessing a given patient's status, both clinically and for evaluating intrinsic (e.g., genetic, chromosomal aberrations) and acquired conditions. There are, however, very few published standards for American Blacks and none for the deciduous teeth. Mesiodistal and buccolingual crown diameters are reported here for a series of 100 Black children. As with the permanent dentition, the primary teeth of Blacks are appreciably larger than Whites, though the amount differs by tooth type. In general, while all teeth are larger than norms for Whites, the posterior teeth (m1, m2) are preferentially larger. Applications of these standards are discussed.

An assay for mandelate racemase using high-performance liquid chromatography.

Mandelate racemase (EC 5.1.2.2) catalyzes the interconversion of the two stereoisomers of mandelic acid. A fixed-time assay for the quantification of mandelate racemase activity has been developed. The assay involves enzymatic conversion of R-mandelate to S-mandelate (or the reverse reaction) followed by separation and detection of the substrate and product using isocratic reversed-phase high-performance liquid chromatography on a Sumichiral OA-6100 column and absorbance detection. This method offers an economical and efficient alternative to the existing circular dichroism-based and coupled assays.