FastJoin, an improved neighbor-joining algorithm.

Reconstructing the evolutionary history of a set of species is an elementary problem in biology, and methods for solving this problem are evaluated based on two characteristics: accuracy and efficiency. Neighbor-joining reconstructs phylogenetic trees by iteratively picking a pair of nodes to merge as a new node until only one node remains; due to its good accuracy and speed, it has been embraced by the phylogeny research community. With the advent of large amounts of data, improved fast and precise methods for reconstructing evolutionary trees have become necessary. We improved the neighbor-joining algorithm by iteratively picking two pairs of nodes and merging as two new nodes, until only one node remains. We found that another pair of true neighbors could be chosen to merge as a new node besides the pair of true neighbors chosen by the criterion of the neighbor-joining method, in each iteration of the clustering procedure for the purely additive tree. These new neighbors will be selected by another iteration of the neighbor-joining method, so that they provide an improved neighbor-joining algorithm, by iteratively picking two pairs of nodes to merge as two new nodes until only one node remains, constructing the same phylogenetic tree as the neighbor-joining algorithm for the same input data. By combining the improved neighbor-joining algorithm with styles upper bound computation optimization of RapidNJ and external storage of ERapidNJ methods, a new method of reconstructing phylogenetic trees, FastJoin, was proposed. Experiments with sets of data showed that this new neighbor-joining algorithm yields a significant speed-up compared to classic neighbor-joining, showing empirically that FastJoin is superior to almost all other neighbor-joining implementations.

[Mass photofluorography in early detection of peripheral lung cancer].

During 5 consecutive years of 100 mm photofluorography, 21 cases of primary lung cancer were discovered among 211,881 checked subjects in 54 factories in the suburbs of Beijing. Detection rate was 9.9/100,000. In the male smokers 40 years old or over, who comprised 13.7% of all examined with a detection rate of 55.0/100,000. Among the 21 cases, peripheral cancer was 61.9%, in which 38.4% were stage I 69.2% were treated by surgical resection, much higher than that of the central type. It may be concluded that photofluorography in mass screening has a certain value in early detection of the peripheral lung cancer and the male smokers 40 years or over should be examined as a priority group.

[Effects of tetramethylpyrazine on platelet functions of advanced cases of lung carcinoma].

OBJECTIVE: To explore the role of hypercoagulation in the metastasis of carcinoma. METHODS: The effect of Tetramethylpyrazine (TTMP) on platelet functions among the 25 advanced cases of lung carcinoma, and 26 matched control subjects were investigated in the study. Their ages varied from 31-86 years (mean 58.2) in lung carcinoma group (13 male, 12 female) and 36 to 61 (mean 52.9) in the control group (16 male, 10 female). The pathologic types were as follows: 7 cases of squamous cell cancer, 12 adenocarcinoma, 2 small cell carcinoma and 4 undistinguished type. The TNM stage revealed 14 cases in stage IIIa, 3 in stage IIIb and 8 in stage IV. The site of metastasis included mediastinal lymph node, pleura, supraclavicular lymph node, brain, spine, costa, skin and pericardium. The levels of plasma TXB2, 6-keto-PGF1 alpha, VIII:C, vWF, AT-III:a, AT-III:Ag, Fg and blood PAdT, PAgT were measured before and after the intravenous infusion of 80 mg TTMP in patients with lung carcinoma. RESULTS: The levels of TXB2, 6-keto-PGF1 alpha, VIII:C, vWF and Fg in lung carcinoma group were significantly elevated, while the levels of PAdT was greatly decreased, compared with the control group, no significant differences in levels of PAgT, AT-III:a and AT-III:Ag were found between the two groups. After the infusion of TTMP the levels of PAdT, PagT, VIII:C, dWF and Fg were decreased significantly, while TXB2, 6-keto-PGF1 alpha, AT-III:a and AT-III:Ag remained unchanged. CONCLUSIONS: TTMP inhibits the adhesion and aggregatory functions of blood platelet and the activity of coagulation factors. It might be one of the mechanisms of TTMP's antimetastasis of lung carcinoma.

Genotyping of clinical Mycobacterium tuberculosis isolates based on eight loci of MIRU-VNTR.

Genotyping that differentiates between strains of Mycobacterium tuberculosis based on variations in the genome of the organism is a useful tool for molecular epidemiological studies of tuberculosis. In the present study, we identified a combination of five mycobacterial interspersed repetitive unit (MIRU) loci and three variable numbers of tandem repeats (VNTR) loci of M. tuberculosis that showed a discriminatory power comparable to that of the 15 to 24 loci-based typing proposed for international standardisation in analysing 210 paediatric isolates obtained from Chongqing, China.