Urinary tuberculosis is associated with the development of urothelial carcinoma but not renal cell carcinoma: a nationwide cohort study in Taiwan.

BACKGROUND: Obstructive uropathy and chronic urinary tract infection increase the risk of urinary tract cancer. Urinary tuberculosis (UTB) can cause chronic urinary tract inflammation, lead to obstructive uropathy, and potentially contribute to the development of urinary tract cancer. However, the association between UTB and urinary tract cancer has not been studied. METHODS: This study enrolled 135 142 tuberculosis (TB) cases (male, 69%) from a nationwide health insurance research database in Taiwan and investigated the risk factors for urinary tract cancer, with emphasis on a history of UTB. The incidence of urinary tract cancer in the general population without TB was also calculated for comparison. RESULTS: The TB patients had a mean age of 57.5 ± 19.5 years. Of the 1287 UTB and 133 855 non-UTB patients, 15 (1.2%) and 396 (0.3%) developed urothelial carcinoma, respectively (P<0.001); and 2 (0.2%) and 96 (0.1%) developed renal cell carcinoma, respectively (P=0.240). Cox regression analysis revealed that age, male sex, end-stage renal disease, obstructive uropathy, arsenic intoxication, organ transplantation, and UTB (hazard ratio: 3.38 (2.01-5.69)) were independent risk factors for urothelial carcinoma. The hazard ratio of UTB was higher among female patients (5.26 (2.12-13.06)) than that among male patients (2.96 (1.57-5.60)). CONCLUSION: Urinary tuberculosis had a strong association with urothelial carcinoma, but not with renal cell carcinoma. In TB endemic areas, the urinary tract of TB patients should be scrutinised. It is also imperative that these patients be followed-up carefully in the post-treatment period, and urinalysis, ultrasonography or endoscopy should be an integral part of the follow-up.

Calign: aligning sequences with restricted affine gap penalties.

MOTIVATION: Given a genomic DNA sequence, it is still an open problem to determine its coding regions, i.e. the region consisting of exons and introns. The comparison of cDNA and genomic DNA helps the understanding of coding regions. For such an application, it might be adequate to use the restricted affine gap penalties which penalize long gaps with a constant penalty. RESULTS: Several techniques developed for solving the approximate string-matching problem are employed to yield efficient algorithms for computing the optimal alignment with restricted affine gap penalties. In particular, efficient algorithms can be derived based on the suffix automaton with failure transitions and on the diagonalwise monotonicity of the cost tables. We have implemented the above methods in C on Sun workstations running SunOS Unix. Preliminary experiments show that these approaches are very promising for aligning a cDNA sequence with a genomic DNA sequence. AVAILABILITY: Calign is available free of charge by anonymous ftp at: iubio.bio. indiana.edu, directory: molbio/align, files: calign.driver.c calign. c. Another URL reference for the files is http://iubio.bio.indiana.edu/soft/molbio/align/+ ++calign.c.

A tool for aligning very similar DNA sequences.

RESULTS: We have produced a computer program, named sim3, that solves the following computational problem. Two DNA sequences are given, where the shorter sequence is very similar to some contiguous region of the longer sequence. Sim3 determines such a similar region of the longer sequence, and then computes an optimal set of single-nucleotide changes (i.e. insertions, deletions or substitutions) that will convert the shorter sequence to that region. Thus, the alignment scoring scheme is designed to model sequencing errors, rather than evolutionary processes. The program can align a 100 kb sequence to a 1 megabase sequence in a few seconds on a workstation, provided that there are very few differences between the shorter sequence and some region in the longer sequence. The program has been used to assemble sequence data for the Genomes Division at the National Center for Biotechnology Information.

A local alignment tool for very long DNA sequences.

This paper presents a practical program, called sim2, for building local alignments of two sequences, each of which may be hundreds of kilobases long. sim2 first constructs n best non-intersecting chains of 'fragments', such as all occurrences of identical 5-tuples in each of two DNA sequences, for any specified n > or = 1. Each chain is then refined by delivering an optimal alignment in a region delimited by the chain. sim2 requires only space proportional to the size of the input sequences and the output alignments, and the same source code runs on Unix machines, on Macintoshes, on PCs, and on DEC Alpha PCs. We also describe an application of sim2 for aligning long DNA sequences from Escherichia coli. sim2 facilitates contig-building by providing a complete view of the related sequences, so differences can be analyzed and inconsistencies resolved. Examples are shown using the alignment display and editing functions from the software tool ChromoScope.

Globin gene server: a prototype E-mail database server featuring extensive multiple alignments and data compilation for electronic genetic analysis.

The sequence of virtually the entire cluster of beta-like globin genes has been determined from several mammals, and many regulatory regions have been analyzed by mutagenesis, functional assays, and nuclear protein binding studies. This very large amount of sequence and functional data needs to be compiled in a readily accessible and usable manner to optimize data analysis, hypothesis testing, and model building. We report a Globin Gene Server that will provide this service in a constantly updated manner when fully implemented. The Server has two principal functions. The first (currently available) provides an annotated multiple alignment of the DNA sequences throughout the gene cluster from representatives of all species analyzed. The second compiles data on functional and protein binding assays throughout the gene cluster. A prototype of this compilation using the aligned 5' flanking region of beta-globin genes from five species shows examples of (1) well-conserved regions that have demonstrated functions, including cases in which the functional data are in apparent conflict, (2) proposed functional regions that are not well conserved, and (3) conserved regions with no currently assigned function. Such an electronic genetic analysis leads to many readily testable hypotheses that were not immediately apparent without the multiple alignment and compilation. The Server is accessible via E-mail on computer networks, and printed results can be obtained by request to the authors. This prototype will be a helpful guide for developing similar tools for many genomic loci.

Recent developments in linear-space alignment methods: a survey.

A dynamic-programming strategy for sequence alignment first proposed in 1975 by Dan Hirschberg can be adapted to yield a number of extremely space-efficient algorithms. Specifically, these algorithms align two sequences using only "linear space," i.e., an amount of computer memory that is proportional to the sum of the lengths of the two sequences being aligned. This paper begins by reviewing the basic idea, as it applies to the global (i.e., end-to-end) alignment of two DNA or protein sequences. Three of our recent extensions of the technique are then outlined. The first extension computes an optimal alignment subject to the constraint that each position, i, of the first sequence must be aligned somewhere between positions L[i] and U[i] of the second sequence, for given values of L and U. The second finds all aligned position pairs (i.e., potential columns of the alignment) that occur in an alignment whose score exceeds a given threshold. The third treats the case where each of the two sequences is allowed to be an alignment (e.g., a sequence of aligned pairs), using a sensitive scoring scheme. We also describe two linear-space methods for computing k best local (i.e., involving only a part of each sequence) alignments, where k > or = 1. One is a linear-space version of the algorithm of Waterman and Eggert (1987), and the other is based on the strategy proposed by Wilbur and Lipman (1983). Finally, we describe programs that implement various combinations of these techniques to provide a multisequence alignment method that is especially suited to handling a few very long sequences. The utility of these programs is illustrated by analysis of the locus control region of the beta-like globin gene cluster of several mammals.

Locating well-conserved regions within a pairwise alignment.

Within a single alignment of two DNA sequences or two protein sequences, some regions may be much better conserved than others. Such strong conservation may reveal a region that possesses an important function. When alignments are so long that it is infeasible, or at least undesirable, to inspect them in complete detail, it is helpful to have an automatic process that computes information about the varying degree of conservation along the alignment and displays the information in a graphical representation that is readily assimilated. This paper presents methods for computing several such 'robustness measures' at each position of a given alignment. These methods are all very space-efficient; they use only space proportional to the sum of the two sequence lengths. To illustrate their effectiveness, one of the methods is used to locate particularly well-conserved regions in the beta-globin gene locus control region and in the 5' flank of the gamma-globin gene.

Constrained sequence alignment.

This paper presents a dynamic programming algorithm for aligning two sequences when the alignment is constrained to lie between two arbitrary boundary lines in the dynamic programming matrix. For affine gap penalties, the algorithm requires only O(F) computations time and O(M+N) space, when F is the area of the feasible region and M and N are the sequence lengths. The result extends to concave gap penalities, with somewhat increased time and space bounds.

Positive and negative regulatory elements of the rabbit embryonic epsilon-globin gene revealed by an improved multiple alignment program and functional analysis.

The epsilon-globin genes of mammals are expressed in early embryos, but are silenced during fetal and adult erythropoiesis. As a guide to defining the regulatory elements involved in this developmental switch, we have searched the sequences of epsilon-globin genes from different mammals for highly conserved segments. The search was facilitated by the development of a new program, called yama, to generate a multiple alignment of very long sequences using an improved scoring scheme. This allowed us to generate a multiple alignment of sequences from a more divergent group than previously analyzed, as demonstrated here for representatives of four mammalian orders. In parallel experiments, we constructed a series of deletion mutations in the 5' flank of the rabbit epsilon-globin gene and tested their effect on an epsilon-globin-luciferase hybrid reporter gene. These results show that 121 bp of 5' flank, containing CACC, CCAAT and ATA motifs, is sufficient for expression in erythroid K562 cells. Both positive and negative cis-acting control sequences are located between 218 and 394 bp 5' to the cap site, in a region previously proposed to be a silencer. The positive regulatory sequence contains conserved binding sites for the nuclear protein YY1 adjacent to another highly conserved sequence. The negative element contains a conserved sequence followed by a purine-rich segment. This analysis maps the upstream control sequences more precisely and points to a very complex regulatory scheme for this gene.

Aligning two sequences within a specified diagonal band.

We describe an algorithm for aligning two sequences within a diagonal band that requires only O(NW) computation time and O(N) space, where N is the length of the shorter of the two sequences and W is the width of the band. The basic algorithm can be used to calculate either local or global alignment scores. Local alignments are produced by finding the beginning and end of a best local alignment in the band, and then applying the global alignment algorithm between those points. This algorithm has been incorporated into the FASTA program package, where it has decreased the amount of memory required to calculate local alignments from O(NW) to O(N) and decreased the time required to calculate optimized scores for every sequence in a protein sequence database by 40%. On computers with limited memory, such as the IBM-PC, this improvement both allows longer sequences to be aligned and allows optimization within wider bands, which can include longer gaps.