The portal vein and its main affluents. An anatomic and morphometric study

There are reported the results of certain measurements made on 158 human cadavers of both sexes. A series of main parameters are given, such as the distance between the superior mesenteric vein and on the one hand its confluence with other vessels and on the other hand the pancreas and the horizontal part of the duodenum: the distance between the superior mesenteric vein together with the portal vein, and the inferior caval vein; the diameters of the portal trunk and the confluence angle between the roots of the portal vein. The results reflect the possibility to perform a troncular portocaval anastomosis in at least 90 per cent of the cases. The authors' attention was, however, directed towards the anatomy of the superior mesenteric vein, as this vessel is preferred by some surgeons in the achievement of the portocaval anastomosis.     

Compositional turnover and variation in Eemian pollen sequences in Europe

Vegetation History and Archaeobotany - The Eemian interglacial represents a natural experiment on how past vegetation with negligible human impact responded to amplified temperature changes...     

Biodiesel fuel from microalgae-promising alternative fuel for the future: a review

The use of organic matter such as vegetable oil to produce biodiesel fuel has been a practical technology for a number of years. However, the search for new technologies and raw materials for biodiesel fuel production has gained increased attention recently because of financial and environmental concerns. Of particular interest are raw materials that are not food-related. Microalgae have gained a great deal of attention as a potential biodiesel raw material because of their high growth rates and ability to accumulate oil, bind carbon dioxide, and remove contaminants from wastewater. This article is a literature review of technologies for biodiesel production from microalgae. The technologies relate to microalgal cultivation, microalgal growth enhancement to simultaneously increase biomass and reduce pollution, the preparation of microalgal biomass for biodiesel production, and biodiesel production itself.     

HCMV-infection in a human arterial organ culture model: effects on cell proliferation and neointimal hyperplasia

Background

The impact of infections with the human cytomegalovirus (HCMV) for the development of atherosclerosis and restenosis is still unclear. Both a clear correlation and no correlation at all have been reported in clinical, mostly serological studies. In our study we employed a human non-injury ex vivo organ culture model to investigate the effect of an in vitro permissive HCMV-infection on cell proliferation and neointimal hyperplasia for a period of 56 days.

Results

During routine-nephrectomies parts of renal arteries from 71 patients were obtained and prepared as human organ cultures. Cell free HCMV infection was performed with the fibroblast adapted HCMV strain AD169, the endotheliotropic strain TB40E, and a clinical isolate (AN 365). After 3, 7, 14, 21, 28, 35, and 56 days in culture staining of HCMV-antigens was carried out and reactive cell proliferation and neointimal thickening were analysed. Successful HCMV-infection was accomplished with all three virus strains studied. During the first 21 days in organ culture no cell proliferation or neointimal hyperplasia was detected. At day 35 and day 56 moderate cell proliferation and neointimal hyperplasia was found both in HCMV-infected segments and mock infected controls. Neointimal hyperplasia in productively HCMV-infected segments was lower than in non infected at day 35 and day 56, but relatively higher after infection with the endotheliotropic TB40E in comparison with the two other strains.

Conclusion

The data do not support the hypothesis that HCMV-infection triggers restenosis via a stimulatory effect on cell proliferation and neointimal hyperplasia in comparison to non infected controls. Interestingly however, even after lytic infection, a virus strain specific difference was observed.     

The Asymmetry of Organic Aerosol Fission and Prebiotic Chemistry

We examine the prebiotic applicability of our recent analysis of the fission of an atmospheric aerosol particle coated with an organic film. The fission is made possible by the free energy change upon compression of the exterior monolayer film on the parent particle, which overcomes the increase in surface area associated with the production of two spherical daughter particles. Asymmetric division into a larger and a smaller particle becomes possible following surfactant film collapse. The size of the airborne parent particle is determined by the balance between aerodynamics and gravity, while the ratio of the radii of the daughters is determined by the compression characteristics of the amphiphilic molecules comprising the parent film. For an Earth atmosphere of one bar surface pressure, the larger and smaller daughters have the sizes of a single-celled bacterium and of a virus respectively. Chemical differentiation between the daughters is possible.     

Conditional Akaike information under generalized linear and proportional hazards mixed models

We study model selection for clustered data, when the focus is on cluster specific inference. Such data are often modelled using random effects, and conditional Akaike information was proposed in Vaida & Blanchard (2005) and used to derive an information criterion under linear mixed models. Here we extend the approach to generalized linear and proportional hazards mixed models. Outside the normal linear mixed models, exact calculations are not available and we resort to asymptotic approximations. In the presence of nuisance parameters, a profile conditional Akaike information is proposed. Bootstrap methods are considered for their potential advantage in finite samples. Simulations show that the performance of the bootstrap and the analytic criteria are comparable, with bootstrap demonstrating some advantages for larger cluster sizes. The proposed criteria are applied to two cancer datasets to select models when the cluster-specific inference is of interest.     

Pyrrolidinone-bearing methylated and halogenated benzenesulfonamides as inhibitors of carbonic anhydrases

Two series of benzenesulfonamides bearing methyl groups at ortho/ortho or meta/ortho positions and a pyrrolidinone moiety at para position were synthesized and tested as inhibitors of the twelve catalytically active human carbonic anhydrase (CA) isoforms. Observed binding affinities were determined by fluorescent thermal shift assay and intrinsic binding affinities representing the binding of benzenesulfonamide anion to the Zn(II)-bound water form of CA were calculated. Introduction of dimethyl groups into benzenesulfonamide ring decreased the binding affinity to almost all CA isoforms, but gained in selectivity towards one CA isoform. A chloro group at the meta position of 2,6-dimethylbenzenesulfonamide derivatives did not influence the binding to CA I, but it increased the affinity to all other CAs, especially, CA VII and CA XIII (up to 500 fold). The compounds may be used for further development of CA inhibitors with higher selectivity to particular CA isoforms.     

Impaired Replication Capacity of Acute/Early Viruses in Persons Who Become HIV Controllers

Human immunodeficiency virus type 1 (HIV-1) controllers maintain viremia at <2,000 RNA copies/ml without antiretroviral therapy. Viruses from controllers with chronic infection were shown to exhibit impaired replication capacities, in part associated with escape mutations from cytotoxic-T-lymphocyte (CTL) responses. In contrast, little is known about viruses during acute/early infection in individuals who subsequently become HIV controllers. Here, we examine the viral replication capacities, HLA types, and virus sequences from 18 HIV-1 controllers identified during primary infection. gag-protease chimeric viruses constructed using the earliest postinfection samples displayed significantly lower replication capacities than isolates from persons who failed to control viremia (P = 0.0003). Protective HLA class I alleles were not enriched in these early HIV controllers, but viral sequencing revealed a significantly higher prevalence of drug resistance mutations associated with impaired viral fitness in controllers than in noncontrollers (6/15 [40.0%] versus 10/80 [12.5%], P = 0.018). Moreover, of two HLA-B57-positive (B57⁺) controllers identified, both harbored, at the earliest time point tested, signature escape mutations within Gag that likewise impair viral replication capacity. Only five controllers did not express “protective” alleles or harbor viruses with drug resistance mutations; intriguingly, two of them displayed typical B57 signature mutations (T242N), suggesting the acquisition of attenuated viruses from B57⁺ donors. These data indicate that acute/early stage viruses from persons who become controllers have evidence of reduced replication capacity during the initial stages of infection which is likely associated with transmitted or acquired CTL escape mutations or transmitted drug resistance mutations. These data suggest that viral dynamics during acute infection have a major impact on HIV disease outcome.Human immunodeficiency virus type I (HIV-1)-infected individuals who control viremia spontaneously without antiviral therapy have been termed HIV controllers (3, 18, 21, 48, 52). Unraveling the mechanisms associated with this phenotype should provide important insights regarding HIV pathogenesis and could contribute to vaccine development.Host and viral genetics, as well as host innate and adaptive immune responses, influence the rate of disease progression in HIV-1 infection (reviewed in reference 18). Several studies have reported the correlation between in vitro HIV replication capacity and level of plasma virus loads or disease progression in individuals with chronic infection (6, 13, 35, 45, 50, 55). Studies of HIV-1 elite controllers (EC), who control viremia to below the limit of detection in commercial assays, have revealed the presence of replication-competent viruses in these individuals (7), although these viruses appear to be less fit based on studies of envelope (35) and Gag-protease (45). This fitness defect in the chronic phase of infection is due at least in part to fitness-impairing mutations induced by cytotoxic-T-lymphocyte (CTL) responses restricted by “protective” HLA class I alleles (46).In contrast, little is known about viruses obtained from the acute/early phase of infection in persons who subsequently become HIV-1 controllers, largely due to the difficulty in enrolling such people during the acute/early phase of infection. The characterization of acute/early-phase viruses in individuals who subsequently achieve low set-point virus loads is of paramount importance to our understanding of the mechanisms of HIV-1 control.In the present study, we analyzed acute/early-phase plasma HIV RNA sequences from 18 untreated individuals who were diagnosed during the acute/early phase and subsequently became controllers (<2,000 RNA copies/ml). We compared these to sequences from a group of HIV-1 noncontrollers enrolled similarly during acute/early infection. We also generated chimeric viruses carrying patient-derived gag-protease sequences from acute/early-phase infection and compared the viral replication capacities of the chimeric viruses from controllers and from noncontrollers.We observed that the chimeric viruses derived from controllers have significantly reduced replicative capacities compared to those from noncontrollers. Moreover, we observed that at least 80% of these individuals who go on to become controllers featured transmission of attenuated drug-resistant viruses, transmission of HLA-B57-restricted CTL escape variants to HLA-mismatched recipients, selection of attenuated CTL escape variants in HLA-B57-positive (B57⁺) recipients, or combinations of these factors. Taken together, these results indicate that the initial viral dynamics have a major influence on the subsequent course of disease.     

Detergent-free domain isolated from Xenopus egg plasma membrane with properties similar to those of detergent-resistant membranes

Microdomains known as "rafts" have been isolated from many cell types as detergent-resistant membranes (DRMs) and are enriched in sphingolipids and cholesterol. However, there has been considerable controversy over whether such domains are found in native membranes or are artificially generated by the purification procedure. This controversy is based at least in part on the fact that raft membranes were first detected following detergent extraction in the cold. We isolated two plasma membrane fractions, without detergent treatment, using a discontinuous sucrose density gradient. One fraction was designated "light" and the other "heavy." These fractions were compared with DRMs, which were isolated in the presence of 1% Triton X-100. We found that Xenopus DRMs are enriched with sphingomyelin and cholesterol and exhibit a phase state similar to the liquid-ordered phase. Comparison of DRM complexes with the light and heavy plasma membrane fractions revealed some physical and biochemical similarities between the light fraction of the plasma membrane and the DRM complexes, based on (1) the phosphatidylcholine/sphingomyelin ratio and (2) the protein composition visualized on a two-dimensional gel. These two fractions are also quite similar in their thermotropic phase behavior, and their high levels of ganglioside GM1. We conclude that the light membrane fraction isolated in a detergent-free environment has many of the characteristics normally associated with DRMs.     

ECG voltage modifications as response to gravity changes

The aim of the study was to analyze ECG (QRS) voltage responses to body fluid shift due to gravity chances. Acute changes in gravity were created by two ways: 1) changes in gravity value during parabolic flights (within 27 subjects 45 ECG have been analyzed); 2) changes in gravity direction due to rotation of the body during postural tests (within 11 subjects 14 ECG have been analyzed). Results and conclusions. Gravity change leads to body fluid shift and changes of intrathoracic organs and tissues electroconduction. It influences on ECG voltage. During parabolic flights in up-right position: R amplitude in Z axis increases in hypergravity (+0.19 mV) and decreases in microgravity (-0.24 mV). During postural tests, R amplitude in Z axis increases in orthostatic position (+0.09 mV) and decreases in antiorthostatic position (-0.025 mV). Changes in QRS voltage during parabolic flights are more important than during postural tests. This could be due to more effective blood redistribution during parabolic flights.