Schistosoma japonicum: the pathology of experimental infection

The pathology of experimental schistosomiasis japonica is reviewed and compared with the pathology of schistosomiasis japonica in man and to some aspects of schistosomiasis mansoni and schistosomiasis haematobia in experimental animals. The induction of granulomas around Schistosoma japonicum eggs depends upon cell mediated immunity, as do the reactions to Schistosoma mansoni and Schistosoma haematobium eggs. However, the modulation of the reaction to S. japonicum eggs can be greatly influenced by antibody, while antibody has no effect on the granulomas around S. mansoni eggs. Adult worm pairs of S. japonicum tend to cluster in the mesenteric venules, and most eggs are laid in a few sites. This leads to large, focal intestinal lesions similar to the discrete lesions produced by S. haematobium in the intestine and urinary tract but in contrast to the widespread, diffuse lesions produced by S. mansoni. Comparison with S. japonicum infection in humans is limited chiefly by our scant knowledge of the pathology produced by S. japonicum in infected persons. Most such comparisons are, in any case, limited by the marked differences in the reactions of various experimental host species to the infection and by differences in the reaction of a given host species to different strains of the parasite.     

Interleukin 2 administered in vivo induces the growth of cultured T cells in vivo

The capacity of exogenous IL 2 to induce the growth of antigen-activated T lymphocytes in vivo was evaluated. The in vivo growth of adoptively transferred T lymphocytes that had been previously cultured long-term with IL 2 was initially examined, because in vitro such T cells are exquisitely dependent upon exogenous IL 2 for proliferation and survival. Daily administration of IL 2 in vivo, beginning on the day of cell transfer, induced these IL 2-dependent long-term cultured T lymphocytes to proliferate in vivo, and the magnitude of in vivo growth was proportional to the dose of IL 2 administered. The capacity of IL 2 to induce the in vivo growth of antigen-activated T cells not previously exposed in vitro to exogenous IL 2 was similarly studied. T lymphocytes from the spleens of immune mice, activated by 5-day culture with tumor antigen before transfer, survived poorly in vivo when injected with antigen alone, but demonstrated marked proliferation in vivo in response to antigen and exogenous IL 2. By contrast, immune spleen cells transferred with antigen, but without prior culture, proliferated without supplementary exogenous IL 2. Moreover, the growth of noncultured donor T cells was not augmented by the administration of exogenous IL 2, implying that noncultured spleen cells immune to tumor antigens can produce sufficient amounts of endogenous IL 2 in vivo to sustain maximal T cell growth over the time period examined. Importantly, the ability of exogenous IL 2 to induce donor T cell growth in vivo correlated with its ability to function in vivo to augment the anti-tumor efficacy of specifically immune donor T cells in models for the adoptive therapy of disseminated antigenic murine leukemia. Thus, the current studies highlight the potential of exogenous IL 2 to induce T cell growth in vivo and suggest that the administration of IL 2 in vivo may be useful for augmenting T cell responses that are relatively deficient in the production of endogenous IL 2.     

A major difference between the divergence patterns within the lines-1 families in mice and voles

L1 retroposons are represented in mice by subfamilies of interspersed sequences of varied abundance. Previous analyses have indicated that subfamilies are generated by duplicative transposition of a small number of members of the L1 family, the progeny of which then become a major component of the murine L1 population, and are not due to any active processes generating homology within preexisting groups of elements in a particular species. In mice, more than a third of the L1 elements belong to a clade that became active approximately 5 Mya and whose elements are > or = 95% identical. We have collected sequence information from 13 L1 elements isolated from two species of voles (Rodentia: Microtinae: Microtus and Arvicola) and have found that divergence within the vole L1 population is quite different from that in mice, in that there is no abundant subfamily of homologous elements. Individual L1 elements from voles are very divergent from one another and belong to a clade that began a period of elevated duplicative transposition approximately 13 Mya. Sequence analyses of portions of these divergent L1 elements (approximately 250 bp each) gave no evidence for concerted evolution having acted on the vole L1 elements since the split of the two vole lineages approximately 3.5 Mya; that is, the observed interspecific divergence (6.7%-24.7%) is not larger than the intraspecific divergence (7.9%-27.2%), and phylogenetic analyses showed no clustering into Arvicola and Microtus clades.      

Molecular phylogeny and divergence times of drosophilid species

The phylogenetic relationships and divergence times of 39 drosophilid species were studied by using the coding region of the Adh gene. Four genera--Scaptodrosophila, Zaprionus, Drosophila, and Scaptomyza (from Hawaii)--and three Drosophila subgenera--Drosophila, Engiscaptomyza, and Sophophora--were included. After conducting statistical analyses of the nucleotide sequences of the Adh, Adhr (Adh-related gene), and nuclear rRNA genes and a 905-bp segment of mitochondrial DNA, we used Scaptodrosophila as the outgroup. The phylogenetic tree obtained showed that the first major division of drosophilid species occurs between subgenus Sophophora (genus Drosophila) and the group including subgenera Drosophila and Engiscaptomyza plus the genera Zaprionus and Scaptomyza. Subgenus Sophophora is then divided into D. willistoni and the clade of D. obscura and D. melanogaster species groups. In the other major drosophilid group, Zaprionus first separates from the other species, and then D. immigrans leaves the remaining group of species. This remaining group then splits into the D. repleta group and the Hawaiian drosophilid cluster (Hawaiian Drosophila, Engiscaptomyza, and Scaptomyza). Engiscaptomyza and Scaptomyza are tightly clustered. Each of the D. repleta, D. obscura, and D. melanogaster groups is monophyletic. The splitting of subgenera Drosophila and Sophophora apparently occurred about 40 Mya, whereas the D. repleta group and the Hawaiian drosophilid cluster separated about 32 Mya. By contrast, the splitting of Engiscaptomyza and Scaptomyza occurred only about 11 Mya, suggesting that Scaptomyza experienced a rapid morphological evolution. The D. obscura and D. melanogaster groups apparently diverged about 25 Mya. Many of the D. repleta group species studied here have two functional Adh genes (Adh-1 and Adh-2), and these duplicated genes can be explained by two duplication events.      

Sulfate reduction and S-oxidation in a moorland pool sediment

In an oligotrophic moorland pool in The Netherlands, S cycling near the sediment/water boundary was investigated by measuring (1) SO₄ ^2– reduction rates in the sediment, (2) depletion of SO₄ ^2– in the overlying water column and (3) release of³⁵S from the sediment into the water column. Two locations differing in sediment type (highly organic and sandy) were compared, with respect to reduction rates and depletion of SO₄ ^2– in the overlying water.Sulfate reduction rates in sediments of an oligotrophic moorland pool were estimated by diagenetic modelling and whole core³⁵SO₄ ^2– injection. Rates of SO₄ ^2– consumption in the overlying water were estimated by changes in SO₄ ^2– concentration over time in in situ enclosures. Reduction rates ranged from 0.27–11.2 mmol m^–2 d^–1. Rates of SO₄ ^2– uptake from the enclosed water column varied from –0.5, –0.3 mmol m^–2 d^–1 (November) to 0.43–1.81 mmol m^–2 d^–1 (July, August and April). Maximum rates of oxidation to SO₄ ^2– in July 1990 estimated by combination of SO₄ ^2– reduction rates and rates of in situ SO₄ ^2– uptake in the enclosed water column were 10.3 and 10.5 mmol m^–2 d^–1 at an organic rich and at a sandy site respectively.Experiments with³⁵S^2– and³⁵SO₄ ^2– tracer suggested (1) a rapid formation of organically bound S from dissimilatory reduced SO₄ ^2– and (2) the presence of mainly non SO₄ ^2–-S derived from reduced S transported from the sediment into the overlying water. A³⁵S^2– tracer experiment showed that about 7% of³⁵S^2– injected at 1 cm depth in a sediment core was recovered in the overlying water column.Sulfate reduction rates in sediments with higher volumetric mass fraction of organic matter did not significantly differ from those in sediments with a lower mass fraction of organic matter.Corresponding author     

Specificity of adoptive chemoimmunotherapy of established syngeneic tumors

To examine the specificity of adoptive chemoimmunotherapy (ACIT) of established syngeneic tumors, two noncross-reactive C57BL/6 tumors were studied: a Friend virus-induced tumor (FBL-3) and a chemically induced virus-negative tumor EL-4(G-). In vitro studies confirmed that these tumors are antigenically distinct by demonstrating that the cytotoxic responses of spleen cells from mice immunized in vivo and reexposed to tumor in vitro are immunologically specific. Studies of ACIT with cells from mice immunized in vivo demonstrated similar specificity. Mice receiving 5 x 10(6) FBL-3 on day 0 all died by day 13. Treatment on day 5 with cyclophosphamide (CY), 180 mg/kg, prolonged the median survival time (MST) to day 23. Treatment on day 5 with CY plus 2 x 10(7) normal nonimmune C57BL/6 cells or CY plus cells sensitized to EL-4(G-) had no additional effect on survival whereas 2 x 10(7) C57BL/6 cells sensitized to FBL-3 in vivo prolonged MST to day 64 and cured 13 of 32 mice. Similarly, mice given 2 x 10(5) EL-4(G-) on day 0 all died by day 16, and CY on day 5 prolonged the MST to day 22. As an adjunct to CY, 2 X 10(7) normal cells or cells sensitized to FBL-3 had a modest effect, prolonging the MST to days 37 and 36, respectively. However, treatment with CY plus 2 x 10(7) cells immune to EL-4(G-) cured 22 of 32 mice. The results demonstrate the immunologic specificity of ACIT of syngeneic tumors treated with immune syngeneic cells.     

Schistosoma mansoni: mice infected with different worm strains.

Infections with five geographical strains and substrains of Schistosoma mansoni were compared in mice. Two substrains (Lc-1 and Lt-1) were derived from the parent (L-1) St. Lucian strain on the basis of differing infectivity for various snail strains. The Puerto Rican strains (PR-1 and PR-2) were obtained with an interval of 25 years. Consistent differences among the lines were found in egg distribution and numbers of eggs in tissues and feces. One Puerto Rican strain (PR-2) and one St. Lucian substrain (Lc-1) had longer prepatent periods than the other strains. Mice infected with the PR-1 strain consistently had the highest egg accumulation in the tissues per worm pair. Relatively few eggs were passed in the feces of the Lt-1 strain. By Week 9 of infection, eggs were noted in the spleens of mice carrying each of the strains and substrains.     

Ant versus bird exclusion effects on the arthropod assemblage of an organic citrus grove

1. Predation‐exclusion experiments have highlighted that top‐down control is pervasive in terrestrial communities, but most of these experiments are simplistic in that they only excluded a single group of predators and the effect of removal was evaluated on a few species from the community. The main goal of our study was to experimentally establish the relative effects of ants and birds on the same arthropod assemblage of canopy trees. 2. We conducted 1‐year long manipulative experiments in an organic citrus grove intended to quantify the independent effects of bird and ant predators on the abundance of arthropods. Birds were excluded with plastic nets whereas ants were excluded with sticky barriers on the trunks. The sticky barrier also excluded other ground dwelling insects, like the European earwig Forficula auricularia L. 3. Both the exclusion of ants and birds affected the arthropod community of the citrus canopies, but the exclusion of ants was far more important than the exclusion of birds. Indeed, almost all groups of arthropods had higher abundance in ant‐excluded than in control trees, whereas only dermapterans were more abundant in bird‐excluded than in control trees. A more detailed analysis conducted on spiders also showed that the effect of ant exclusion was limited to a few families rather than being widespread over the entire diverse spectrum of spiders. 4. Our results suggest that the relative importance of vertebrate and invertebrate predators in regulating arthropod populations largely depends on the nature of the predator–prey system.     

早期液体复苏对感染性休克患者血流动力学的影响

目的：早期液体复苏对感染性休克患者血流动力学的影响。方法：选取2012年2月-2013年2月我院ICU收治的26例感染性休克患者作为研究对象,随机分为对照组和试验组,各13例。两组患者均采用PICCO监测,并根据早期复苏目标导向（Earlygoaldirectedtherapy,EGDT）进行早期液体复苏治疗。对照组和试验组复苏液分别为林格液和6％羟乙基淀粉130／0．4氯化钠溶液。分别于复苏开始时（Oh）、8h和24h收集患者的血流动力学参数。结果：两组患者CO及PAWP水平均随着时间的延长下降,而CI、CVP及SVR水平均随着时间的增加上升。除对照组CI外,与开始复苏（oh）相比较试验组和对照组的C0、CI、CVP、SVR及PAWP与开始复苏（O小时）相比较均有显著差异（P值均〈0．05）。经重复测量资料的．方差分析进行比较发现,与对照组相比较,试验组CVP和SVR上升水平及PAWP下降水平明显,差异具有统计学意义（P值均〈0．05）。结论：感染性休克患者使用6％羟乙基淀粉130／0．4氯化钠溶液进行复苏,能更好的改善患者的血流动力学指标。