Oral findings and periodontal status in children, adolescents and young adults suffering from renal failure.

AIM: Describe the oral condition of chronic renal failure and healthy subjects, and the relationship between oral variables, chronic renal failure (CRF) conditions, and their treatment. MATERIALS AND METHODS: Four renal failure groups: chronic renal disease (n=22); undergoing dialysis (n=22); after dialysis and transplant (n=21); and after transplant (n=32), and a healthy control (n=38) were examined. Caries, enamel hypoplasia, pulp obliteration, plaque index, gingival bleeding, recession, overgrowth and index, probing depths, attachment loss, renal treatments and their relations with the oral variables were analysed. RESULTS: The renal failure groups had higher gingival index (GI) and bleeding, probing depths, attachment loss, hypoplasia and obliteration and less caries, than the control. Plaque was higher in the dialysis and pre-dialysis (PD) groups. Overgrowth was evident after transplant. The PD group showed lower GI than other renal groups. Dialysis duration and end-stage renal failure significantly correlated with gingivitis, probing depth, attachment loss and enamel hypoplasia. Immuran correlated positively with probing depth, gingival recession and attachment loss. Normiten and Nifedipine had positive correlations with gingival overgrowth. CONCLUSIONS: CRF patients are characterized by pulp obliteration, gingival and periodontal diseases. Duration of end stage renal failure and type of systemic treatment have a significant influence on the oral condition.

Nucleotide sequences of five maize chloroplast transfer RNA genes and their flanking regions.

Maize chloroplast tRNA genes encoding tRNA3Ser, tRNAPhe, tRNA2Thr, tRNA2Leu, and tRNAmMet, and their flanking regions have been sequenced. All five gene sequences show features commonly found in the few chloroplast tRNA genes sequenced so far; none of them encodes the 3'-terminal CCA triplet and none of them shows abnormal loop or stem lengths as seen in some genes for mammalian mitochondrial tRNAs. The 5'-flanking regions of some of these tRNA genes contain nucleotide stretches strongly homologous to -35 and -10 promoter regions of bacterial genes. Analysis of these conserved regions together with those seen in other plastid genes yields the consensus sequences ATTGANA at "-35" and TAAGAT at "-10." The 3'-flanking regions of some tRNA genes show dyad symmetries followed by a stretch of Thds. These and other regions may be involved in transcription termination or transcript processing.

Structural and functional analysis of an rRNA operon and its flanking tRNA genes from Zea mays chloroplasts.

The complete analysis of an rRNA operon from Zea mays chloroplasts and its comparison with other plastidic or bacterial rRNA operons is presented. The maize operon contains structural genes for 16S, 23S and 4.5S rRNA species, a leader region proximal to the 16S rRNA gene and a 2.4 kb spacer between the 16S and 23S rRNA genes. Within the spacer DNA sequence are two tRNA genes which code for a tRNAIle and tRNAAla species but each gene is split by large intervening sequences of 949 and 806 bp, respectively. 4.5S rRNA is a structural equivalent of the 3' terminal region of bacterial 23S rRNA. The operon is flanked at its 5' side by a tRNAVal gene and at its 3' side by a 5S rRNA gene. Both these genes are probably not included in the large, primary precursor rRNA transcript.

A gene coding for tRNA is located near 5' terminus of 16S rRNA gene in Zea mays chloroplast genome.

A region of 635 base pairs preceding a gene for 16S rRNA in the Zea mays chloroplast genome has been mapped and its sequence has been determined. Screening for structural elements common to tRNAs reveals a gene coding for tRNA(Val) (GU(U) (C)) positioned 303 base pairs proximal to the 5' end of the 16S rRNA gene. Both the tRNA(Val) and the 16S rRNA are coded in the same DNA strand. The tRNA nucleotide sequence predicted from the DNA sequence meets all structural characteristics common to tRNA primary and secondary structures. In a quantitative comparison with primary structures of the 14 known tRNA(Val) species the chloroplast isoaceptor shows much higher homology with that from prokaryotic than that from eukaryotic species. Regions that Escherichia coli RNA polymerase protects from nuclease attack are observed 25 and 100 base pairs upstream of the tRNA(Val) gene and 105 base pairs upstream of the 16S rRNA gene. Within these regions are short sequences that are very similar to those in the -35 region of E. coli rrn and that may therefore represent all or parts of transcription initiation signals of the respective genes.

Overlapping divergent genes in the maize chloroplast chromosome and in vitro transcription of the gene for tRNA.

In the presence of the S polypeptide, maize chloroplast DNA-dependent RNA polymerase preferentially transcribes sequences within the 2200-nucleotide-pair-long maize chloroplast chromosome fragment Eco [unk] from a supercoiled chimeric plasmid cloned in Escherichia coli [Jolly, S. O. & Bogorad, L. (1980) Proc. Natl. Acad. Sci. USA 77, 822-826]. Eco [unk] contains one gene for tRNA(His) and one for a 1.6-kilobase RNA that includes an open reading frame. These two genes overlap by at least a few nucleotides and are transcribed divergently from complementary DNA strands. This indicates possible transcriptional regulation of chloroplast DNA at the nucleotide level. The 5' end of tRNA(His) (G-U-G) isolated from maize chloroplasts is indistinguishable from that of the transcript produced from Eco [unk] in vitro by maize chloroplast DNA-dependent RNA polymerase. This purified system initiates RNA synthesis faithfully and exhibits preference for some chloroplast genes. Maize chloroplast DNA for tRNA(His) lacks the sequence C-C-A at its 3' terminus; it is presumably added post-transcriptionally. Maize tRNA(His) has both prokaryotic and eukaryotic features.