Metamorphic reworking of a high pressure–low temperature mélange along the Motagua fault, Guatemala: A record of Neocomian and Maastrichtian transpressional tectonics

The Guatemala suture zone is a major east–west left-lateral strike slip boundary that separates the North American and Caribbean plates in Guatemala. The Motagua fault, the central active strand of the suture zone, underwent two major collisional events within a system otherwise dominated by strike–slip motion. The first event is recorded by high-pressure/low temperature (HP/LT) eclogites and related rocks that occur within serpentinites both north and south of the Motagua fault. Lawsonite eclogites south of the fault are not significantly retrograded and give 40Ar/39Ar ages of 125–116 Ma and Sm–Nd mineral isochrons of 144–132 Ma. Eclogites north of the fault give similar Sm–Nd isochron ages (131–126 Ma) but otherwise differ in that they are strongly overprinted by a lower pressure assemblage and, along with associated HP/LT rocks, give much younger 40Ar/39Ar ages of 88–55 Ma indicating a later amphibolite facies metamorphic event. We propose therefore that all serpentinite hosted eclogites along the Motagua fault formed at essentially the same time in different parts of a laterally extensive Lower Cretaceous forearc subduction system, but subsequently underwent different histories. The southern assemblages were thrust southwards (present coordinates) immediately after HP metamorphism whereas the northern association was retrograded during a later collision that thrust it northward at ca. 70 Ma. They were subsequently juxtaposed opposite each other by major strike slip motion. This model implies that the HP rocks on opposing sides of the Motagua fault evolved along a plate boundary that underwent both dip slip and strike slip motion throughout the Late Cretaceous as a result of oblique convergence. The juxtaposition of a convergent and strike slip system means that HP/LT rocks within serpentinites can be found at depth along much of the modern Guatemala suture zone and its eastward extension into the northern Caribbean. Both sets of assemblages were exhumed relatively recently by the uplift of mountain ranges on both sides of the fault caused by movement along a restraining bend. Recent exhumation explains the apparently lack of offset of surface outcrops along a major strike slip fault

Asymptotic expansions of the solutions of the Cauchy problem for nonlinear parabolic equations

Let $u$ be a solution of the Cauchy problem for the nonlinear parabolic equation $$\partial_t u=\Delta u+F(x,t,u,\nabla u) \quad in \quad{\bf R}^N\times(0,\infty), \quad u(x,0)=\varphi(x)\quad in \quad{\bf R}^N,$$ and assume that the solution $u$ behaves like the Gauss kernel as $t\to\infty$. In this paper, under suitable assumptions of the reaction term $F$ and the initial function $\varphi$, we establish the method of obtaining higher order asymptotic expansions of the solution $u$ as $t\to\infty$. This paper is a generalization of our previous paper, and our arguments are applicable to the large class of nonlinear parabolic equations

Androgen Regulated Genes in Human Prostate Xenografts in Mice: Relation to BPH and Prostate Cancer

Benign prostatic hyperplasia (BPH) and prostate carcinoma (CaP) are linked to aging and the presence of androgens, suggesting that androgen regulated genes play a major role in these common diseases. Androgen regulation of prostate growth and development depends on the presence of intact epithelial-stromal interactions. Further, the prostatic stroma is implicated in BPH. This suggests that epithelial cell lines are inadequate to identify androgen regulated genes that could contribute to BPH and CaP and which could serve as potential clinical biomarkers. In this study, we used a human prostate xenograft model to define a profile of genes regulated in vivo by androgens, with an emphasis on identifying candidate biomarkers. Benign transition zone (TZ) human prostate tissue from radical prostatectomies was grafted to the sub-renal capsule site of intact or castrated male immunodeficient mice, followed by the removal or addition of androgens, respectively. Microarray analysis of RNA from these tissues was used to identify genes that were; 1) highly expressed in prostate, 2) had significant expression changes in response to androgens, and, 3) encode extracellular proteins. A total of 95 genes meeting these criteria were selected for analysis and validation of expression in patient prostate tissues using quantitative real-time PCR. Expression levels of these genes were measured in pooled RNAs from human prostate tissues with varying severity of BPH pathologic changes and CaP of varying Gleason score. A number of androgen regulated genes were identified. Additionally, a subset of these genes were over-expressed in RNA from clinical BPH tissues, and the levels of many were found to correlate with disease status. Our results demonstrate the feasibility, and some of the problems, of using a mouse xenograft model to characterize the androgen regulated expression profiles of intact human prostate tissues

Living donor liver transplantation from a donor previously treated with interferon for hepatitis C virus: a case report

<p>Abstract</p> <p>Introduction</p> <p>Selecting a marginal donor in liver transplantation (LT) remains controversial but is necessary because of the small number of available donors.</p> <p>Case presentation</p> <p>A 46-year-old Japanese woman was a candidate to donate her liver to her brother, who had decompensated liver cirrhosis of unknown origin. Eight years before the donation, she had a mild liver dysfunction that was diagnosed as a hepatitis C virus (HCV) infection (serotype 2). She had received anti-viral therapy with interferon α-2b three times weekly for 24 weeks and had a sustained viral response (SVR). A biopsy of her liver before the donation showed normal findings without any active hepatitis, and her serum was negative for HCV-RNA. Only 67 patients have undergone LT from a cadaveric donor in Japan. The family in this case decided to have living donor LT. A careful selection for the liver graft donation was made; however, since she was the only candidate, we approved her as a living donor. She was discharged nine days after the liver donation. Her liver function recovered immediately. A computed tomography scan showed sufficient liver regeneration one year later. Her brother also had good liver function after LT and had no HCV infection 48 months after surgery and no <it>de novo </it>malignancy. Neither of the siblings has developed an HCV infection.</p> <p>Conclusions</p> <p>A patient with SVR status after interferon therapy might be considered a candidate for living donor LT but only if there are no other possibilities of LT for the recipient. A careful follow-up of the donor after donation is needed. The recipient also must have a very close follow-up because it is difficult to predict what might happen to the graft with post-transplant immunosuppression.</p

Practical Science and Environmental Education Workshop in Manaus, Brazil

It is an unequivocal fact that Amazonian tropical forest is the largest remaining primary forest in the world. The ecosystem in the region is e tremely comple with high biodiversity (Peres et al. 2010). Conservation and protection of the dynamic forest and river regions is e tremely important not only for the natural environments, but also for the economy and social dependence of benefits from such abundant natural environments. Important natural parameters that affect status of the natural environments include light (natural sunlight), soil, and water, which abundantly e ist in the Amazon region. Solar energy is the primary energy source for the majority of living organisms in both terrestrial and aquatic ecosystems, and drives the diurnal and seasonal cycles of biogeochemical processes (Monteith & Unsworth 2013). In particular, in situ light data remains one of the most underappreciated data measurements although having a significant impact on the physical, chemical and biological processes in the ecosystem (Johnsen 2012). Soil provides the fundamental basis for all terrestrial living organisms including the Amazonian forests as well as life-sustaining infrastructure for human society. Water is the most essential single entity to constitute all organisms from a single cell to the earth. Understanding of importance and roles of each factor and interaction of such comple dynamics in the natural environments can serve as fundamental platform for natural scientists, particularly for young scientists such as university students. The objective of this workshop was to provide hand- on scientific and environmental education for university students in Manaus, Amazonas, Brazil through practical field measurements using the three most important parameters in the natural ecosystem composed of natural sunlight, soil, and water. The workshop was divided into a series of lectures, in situ field sampling, and data processing, analysis and interpretation with the ultimate goal of empowering the undergraduate students with research-centered environmental education and e perience of developing international collaboration.departmental bulletin pape

Paradoxical expression of IL-28B mRNA in peripheral blood in human T-cell leukemia virus Type-1 mono-infection and co-infection with hepatitis C Virus

<p>Abstract</p> <p>Background</p> <p>Human T-cell leukemia virus type-1 (HTLV-1) carriers co-infected with and hepatitis C virus (HCV) have been known to be at higher risk of their related diseases than mono-infected individuals. The recent studies clarified that IL-28B polymorphism rs8099917 is associated with not only the HCV therapeutic response by IFN, but also innate immunity and antiviral activity. The aim of our research was to clarify study whether IL-28B gene polymorphism (rs8099917) is associated with HTLV-1/HCV co-infection.</p> <p>Results</p> <p>The genotyping and viral-serological analysis for 340 individuals showed that IL-28B genotype distribution of rs8099917 SNP did not differ significantly by respective viral infection status. However, the IL-28B mRNA expression level was 3.8 fold higher in HTLV-1 mono-infection than HTLV-1/HCV co-infection. The high expression level was associated with TT (OR, 6.25), whiles the low expression was associated with co-infection of the two viruses (OR, 9.5). However, there was no association between down-regulation and ATL development (OR, 0.8).</p> <p>Conclusion</p> <p>HTLV-1 mono-infection up-regulates the expression of IL-28B transcripts in genotype-dependent manner, whiles HTLV-1/HCV co-infection down-regulates regardless of ATL development.</p

Plasma MicroRNA Profiles in Rat Models of Hepatocellular Injury, Cholestasis, and Steatosis

MicroRNAs (miRNAs) are small RNA molecules that function to modulate the expression of target genes, playing important roles in a wide range of physiological and pathological processes. The miRNAs in body fluids have received considerable attention as potential biomarkers of various diseases. In this study, we compared the changes of the plasma miRNA expressions by acute liver injury (hepatocellular injury or cholestasis) and chronic liver injury (steatosis, steatohepatitis and fibrosis) using rat models made by the administration of chemicals or special diets. Using miRNA array analysis, we found that the levels of a large number of miRNAs (121–317 miRNAs) were increased over 2-fold and the levels of a small number of miRNAs (6–35 miRNAs) were decreased below 0.5-fold in all models except in a model of cholestasis caused by bile duct ligation. Interestingly, the expression profiles were different between the models, and the hierarchical clustering analysis discriminated between the acute and chronic liver injuries. In addition, miRNAs whose expressions were typically changed in each type of liver injury could be specified. It is notable that, in acute liver injury models, the plasma level of miR-122, the most abundant miRNA in the liver, was more quickly and dramatically increased than the plasma aminotransferase level, reflecting the extent of hepatocellular injury. This study demonstrated that the plasma miRNA profiles could reflect the types of liver injury (e.g. acute/chronic liver injury or hepatocellular injury/cholestasis/steatosis/steatohepatitis/fibrosis) and identified the miRNAs that could be specific and sensitive biomarkers of liver injury

Protein Phosphatase 2A Controls Ethylene Biosynthesis by Differentially Regulating the Turnover of ACC Synthase Isoforms

The gaseous hormone ethylene is one of the master regulators of development and physiology throughout the plant life cycle. Ethylene biosynthesis is stringently regulated to permit maintenance of low levels during most phases of vegetative growth but to allow for rapid peaks of high production at developmental transitions and under stress conditions. In most tissues ethylene is a negative regulator of cell expansion, thus low basal levels of ethylene biosynthesis in dark-grown seedlings are critical for optimal cell expansion during early seedling development. The committed steps in ethylene biosynthesis are performed by the enzymes 1-aminocyclopropane 1-carboxylate synthase (ACS) and 1-aminocyclopropane 1-carboxylate oxidase (ACO). The abundance of different ACS enzymes is tightly regulated both by transcriptional control and by post-translational modifications and proteasome-mediated degradation. Here we show that specific ACS isozymes are targets for regulation by protein phosphatase 2A (PP2A) during Arabidopsis thaliana seedling growth and that reduced PP2A function causes increased ACS activity in the roots curl in 1-N-naphthylphthalamic acid 1 (rcn1) mutant. Genetic analysis reveals that ethylene overproduction in PP2A-deficient plants requires ACS2 and ACS6, genes that encode ACS proteins known to be stabilized by phosphorylation, and proteolytic turnover of the ACS6 protein is retarded when PP2A activity is reduced. We find that PP2A and ACS6 proteins associate in seedlings and that RCN1-containing PP2A complexes specifically dephosphorylate a C-terminal ACS6 phosphopeptide. These results suggest that PP2A-dependent destabilization requires RCN1-dependent dephosphorylation of the ACS6 C-terminus. Surprisingly, rcn1 plants exhibit decreased accumulation of the ACS5 protein, suggesting that a regulatory phosphorylation event leads to ACS5 destabilization. Our data provide new insight into the circuitry that ensures dynamic control of ethylene synthesis during plant development, showing that PP2A mediates a finely tuned regulation of overall ethylene production by differentially affecting the stability of specific classes of ACS enzymes