三氧化二砷对食管癌细胞增殖和热休克蛋白70表达的影响

目的：研究三氧化二砷（As2O3）对食管癌细胞增殖和热休克蛋白70（HSP70）表达的影响。方法：通过相差显微镜、流式细胞术、免疫细胞化学染色和免疫印迹分析等方法观察As2O3对人食管癌细胞株EC1的作用效果和作用机制。结果：与对照组相比,经2μmol/L和5μmol/Las2O3作用的细胞出现明显的生长抑制,G2/M期细胞比例增加;2μmol/Las2O3作用48h后经Ecl细胞HSP70（heat shock protein70）及HSC70(heat shock cognate protein70)表达均增加。结论：As2O3诱导食管癌细胞G2/M期阻滞抑制细胞增殖和生长;HSP70的升高是细胞对As2O3作用后出现的应激反应,并与细胞周期阻滞相关。     

Tetrapod phylogeny inferred from 18S and 28S ribosomal RNA sequences and a review of the evidence for amniote relationships [published erratum appears in Mol Biol Evol 1991 May;8(3):398]

The 18S ribosomal RNAs of 21 tetrapods were sequenced and aligned with five published tetrapod sequences. When the coelacanth was used as an outgroup, Lissamphibia (living amphibians) and Amniota (amniotes) were found to be statistically significant monophyletic groups. Although little resolution was obtained among the lissamphibian taxa, the amniote sequences support a sister-group relationship between birds and mammals. Portions of the 28S ribosomal RNA (rRNA) molecule in 11 tetrapods also were sequenced, although the phylogenetic results were inconclusive. In contrast to previous studies, deletion or down- weighting of base-paired sites were found to have little effect on phylogenetic relationships. Molecular evidence for amniote relationships is reviewed, showing that three genes (beta-hemoglobin, myoglobin, and 18S rRNA) unambiguously support a bird-mammal relationship, compared with one gene (histone H2B) that favors a bird- crocodilian clade. Separate analyses of four other genes (alpha- crystallin A, alpha-hemoglobin, insulin, and 28S rRNA) and a combined analysis of all sequence data are inconclusive, in that different groups are defined in different analyses and none are strongly supported. It is suggested that until sequences become available from a broader array of taxa, the molecular evidence is best evaluated at the level of individual genes, with emphasis placed on those studies with the greatest number of taxa and sites. When this is done, a bird-mammal relationship is most strongly supported. When regarded in combination with the morphological evidence for this association, it must be considered at least as plausible as a bird-crocodilian relationship.      

Biological activities of 17-phenyl-18,19,20-trinorprostaglandins

In a number of assay ssytems, some 17-phenyl-trinor prostaglandins were similar in activity and potency to the corresponding parent prostaglandin. In others, the 17-phenyl analogs appeared several times more potent. In the hamster antifertility assay, which is considered to measure luteolytic activity, 17-phenyl-18,19,20-trinor prostaglandin F_2α was about 90-times PGF_2α in potency.Rat blood pressure responses to 17-phenyl analogs were significant. The 17-phenyl-trinor PGF_2α pressor potency was 5 times that of PGF_2α. The 17-phenyl-trinor PGE₂ blood pressure response was atypical since a pressor rebound phenomenon followed the expected depressor response. Lastly, 17-phenyl-trinor PGF_2α was more potent than PGF_2α in synchronizing the estrous cycle in beef cows.     

Infectious salmon anaemia virus (ISAV) isolated from the ISA disease outbreaks in Chile diverged from ISAV isolates from Norway around 1996 and was disseminated around 2005, based on surface glycoprotein gene sequences

Background

All viruses in the family Bunyaviridae possess a tripartite genome, consisting of a small, a medium, and a large RNA segment. Bunyaviruses therefore possess considerable evolutionary potential, attributable to both intramolecular changes and to genome segment reassortment. Hantaviruses (family Bunyaviridae, genus Hantavirus) are known to cause human hemorrhagic fever with renal syndrome or hantavirus pulmonary syndrome. The primary reservoir host of Sin Nombre virus is the deer mouse (Peromyscus maniculatus), which is widely distributed in North America. We investigated the prevalence of intramolecular changes and of genomic reassortment among Sin Nombre viruses detected in deer mice in three western states.

Methods

Portions of the Sin Nombre virus small (S) and medium (M) RNA segments were amplified by RT-PCR from kidney, lung, liver and spleen of seropositive peromyscine rodents, principally deer mice, collected in Colorado, New Mexico and Montana from 1995 to 2007. Both a 142 nucleotide (nt) amplicon of the M segment, encoding a portion of the G2 transmembrane glycoprotein, and a 751 nt amplicon of the S segment, encoding part of the nucleocapsid protein, were cloned and sequenced from 19 deer mice and from one brush mouse (P. boylii), S RNA but not M RNA from one deer mouse, and M RNA but not S RNA from another deer mouse.

Results

Two of 20 viruses were found to be reassortants. Within virus sequences from different rodents, the average rate of synonymous substitutions among all pair-wise comparisons (π_s) was 0.378 in the M segment and 0.312 in the S segment sequences. The replacement substitution rate (π_a) was 7.0 × 10^-4 in the M segment and 17.3 × 10^-4 in the S segment sequences. The low π_a relative to π_s suggests strong purifying selection and this was confirmed by a Fu and Li analysis. The absolute rate of molecular evolution of the M segment was 6.76 × 10^-3 substitutions/site/year. The absolute age of the M segment tree was estimated to be 37 years. In the S segment the rate of molecular evolution was 1.93 × 10^-3 substitutions/site/year and the absolute age of the tree was 106 years. Assuming that mice were infected with a single Sin Nombre virus genotype, phylogenetic analyses revealed that 10% (2/20) of viruses were reassortants, similar to the 14% (6/43) found in a previous report.

Conclusion

Age estimates from both segments suggest that Sin Nombre virus has evolved within the past 37–106 years. The rates of evolutionary changes reported here suggest that Sin Nombre virus M and S segment reassortment occurs frequently in nature.     

Patterns of maxillofacial injuries in powered watercraft collisions

Because of the widespread popularity of water sports, plastic and reconstructive surgeons can expect to manage an increasing number of injuries associated with these activities, particularly those related to powered watercraft vehicles. Although seat belts for motorists and helmets for motorcyclists may be efficacious, such devices currently do not serve a similar role in powered watercraft sports. In this study, a retrospective chart review of 194 consecutive patients who presented to the University of Miami/Jackson Memorial Hospital (Level I trauma center) as a result of powered watercraft collisions is presented. The purpose of this investigation was to assess the incidence, cause, demographics, and available management options for head and neck injuries secondary to powered watercraft. Identified were 194 patients who presented because of watersports-related injuries during the period January 1, 1991, through December 31, 1996. From this group, 81 patients (41.8 percent) sustained injuries directly attributable to powered watercraft collisions, including 41 personal watercraft collisions (50.6 percent), 39 boat collisions (48.1 percent), and 1 airboat collision (1.2 percent). The patient population, as expected, tended to be young and male with an average age of 29 years (range, 8 to 64 years old). Interestingly, 41 of the patients (50.6 percent) who presented to this trauma center as a result of powered watercraft collisions also sustained associated head and neck trauma. Of 74 injuries 24 were facial fractures (32.4 percent), 18 were facial lacerations (24.3 percent), 14 were closed head injuries (18.9 percent), 8 were skull fractures (10.8 percent), 4 were scalp lacerations (5.4 percent), 4 were C-spine fractures (5.4 percent), 1 was an ear laceration (1.4 percent), and 1 was a fatality (1.4 percent). Le Fort fractures were the most commonly identified facial fracture in this series. The number of these injuries seen in hospital emergency rooms will most likely increase in the future as the popularity of water-related recreational activities becomes even more widespread. Based on these findings, it is strongly recommended that future efforts be directed toward the prevention of these injuries through patient education and the eventual development of efficacious and safe protective equipment.