Salvage of jeopardized myocardium by ischemic preconditioning: Is the quest over?

Helmholtz is quoted to have said that if he'd had any influence in creation he would have returned the human eye to its maker for revisions. The same could be said of the heart with its only very rudimentary ability to defend itself against ischemia. Ischemia was obviously not a problem during evolution: Early man did not live much longer than prime time for reproduction and no selection bias existed to prevent vascular diseases, an affliction of later life. In spite of this natural disadvantage of aged males the number of existing although not very efficient defense mechanisms is surprisingly large. It is the general belief that the knowledge of these mechanisms may lead to the development of new therapies that hopefully improve the imperfect product of natural selection. (Mol Cell Biochem 160/161: 209–215, 1996)     

The effects of drift and selection on latitudinal genetic variation in Scandinavian common toads (Bufo bufo) following postglacial recolonisation

Clinal variation is paramount for understanding the factors shaping genetic diversity in space and time. During the last glacial maximum, northern Europe was covered by glacial ice that rendered the region uninhabitable for most taxa. Different evolutionary processes during and after the recolonisation of this area from different glacial refugia have affected the genetic landscape of the present day European flora and fauna. In this study, we focus on the common toad (Bufo bufo) in Sweden and present evidence suggesting that these processes have resulted in two separate lineages of common toad, which colonised Sweden from two directions. Using ddRAD sequencing data for demographic modelling, structure analyses, and analysis of molecular variance (AMOVA), we provide evidence of a contact zone located between Uppland and Västerbotten in central Sweden. Genetic diversity was significantly higher in southern Sweden compared to the north, in accordance with a pattern of decreased genetic diversity with increasing distance from glacial refugia. Candidate genes under putative selection are identified through outlier detection and gene–environment association methods. We provide evidence of divergent selection related to stress response and developmental processes in these candidate genes. The colonisation of Sweden by two separate lineages may have implications for how future conservation efforts should be directed by identifying management units and putative local adaptations.Subject terms: Evolutionary genetics, Genomics, Genetic variation     

ADAPTIVE POPULATION DIVERGENCE IN CRYPTIC COLOR-PATTERN FOLLOWING A REDUCTION IN GENE FLOW

Adaptive population divergence is often driven by divergent natural selection, but can be constrained by the homogenizing effect of gene flow between populations. Indeed, a common pattern in nature is an inverse correlation between the degree of adaptive phenotypic divergence between populations and levels of gene flow between populations. However, there is essentially no experimental data on whether this correlation arises because gene flow constrains adaptation or, conversely, because adaptive divergence causes barriers to gene flow (ecological speciation). Here, I report increased adaptive divergence in cryptic color pattern between a pair of Timema insect populations following an experimental reduction in between-population gene flow. The reduction in gene flow arose due to a natural experiment, and thus was not replicated at a second site. However, temporal replication of the trends among six generations of data, coupled with a lack of increased adaptive divergence for two other population pairs where gene flow was not manipulated (i.e., control sites), argues that the results did not arise by chance. Estimates of dispersal ability and population size further support reduced gene flow, rather than increased genetic drift, as the cause of divergence. Thus, the findings provide experimental evidence that gene flow constrains adaptation in nature.     

Pulsatile blood flow, shear force, energy dissipation and Murray's Law

Background  

Murray's Law states that, when a parent blood vessel branches into daughter vessels, the cube of the radius of the parent vessel is equal to the sum of the cubes of the radii of daughter blood vessels. Murray derived this law by defining a cost function that is the sum of the energy cost of the blood in a vessel and the energy cost of pumping blood through the vessel. The cost is minimized when vessel radii are consistent with Murray's Law. This law has also been derived from the hypothesis that the shear force of moving blood on the inner walls of vessels is constant throughout the vascular system. However, this derivation, like Murray's earlier derivation, is based on the assumption of constant blood flow.     

Koralionastetales, a new order of marine Ascomycota in the Sordariomycetes

Based on molecular studies using 1760 bp of the nuSSU and 604 bp of the nuLSU rRNA genes and using morphological characters, the genera Koralionastes and Pontogeneia are assigned to the new order Koralionastetales, family Koralionastetaceae, class Sordariomycetes. Koralionastetales is a sister group to Lulworthiales; differences in morphological characters are expressed in the ascospores and the presence/absence of periphyses and paraphyses. A new species of Pontogeneia, P. microdictyi from Microdictyon sp. in the Bahamas, is described.     

Littoral macrofauna (secondary) responses to experimental nutrient addition to rocky shore mesocosms and a coastal lagoon

Macrofauna secondary responses to controlled eutrophication within two MARICULT/MAST-III projects, EULIT and COMWEB, are compared. EULIT utilises a nutrient gradient established in eight hard bottom mesocosms, whereas the data from COMWEB originate from a whole-ecosystem study – the case of experimental nutrient addition to Hopavågen lagoon. In both systems, nutrient addition started in May 1998, after initial studies of the background macrofauna communities, thus allowing application of Before-After-Control-Impact-Pairs techniques (BACIP). The main objectives have been to investigate the macrofauna responses to eutrophication in littoral rocky shore ecosystems and to evaluate if similar responses could occur in mesocosm and `field' systems, despite their inherent differences. Apart from a distinct increase in numbers of Littorina littorea L. and some indications of increased abundance of the genus Jaera, no significant changes, caused by 2.5 years of nutrient addition, could be detected in the mesocosm fauna. It is interesting, however, that these two possibly stimulated animal groups have two things in common: (1) both belong to the rather few mobile taxa, which are not flushed out of the system through the mesocosm outlets, (2) both feed on microalgae and green algae in the upper littoral zone, i.e., algal groups that have shown the clearest response to the nutrient addition. In Hopavågen, 1.5 years of nutrient addition only caused modest plant and animal responses in the rocky shore ecosystem, although there was a markedly increased settlement of Mytilus edulis L. at one lagoon site. This increase was probably due to elevated levels of digestible particles (increased phytoplankton production) caused by the nutrient addition. There were also some indications of increased production of filamentous algae at this same lagoon site. All in all, both studies demonstrate only minor responses to increased nutrient levels within the littoral community (both plants and animals). One explanation to this may be that longer time-scales are needed in order for clear-cut changes to occur. Several observations also indicate that wave exposure (significant in both systems) may largely modulate the impact of increased nutrient load on the structure of littoral communities. Another explanation is the high degree of stability among littoral macroalgae-dominated communities with internal biological regulation factors (like grazing) possibly being able to counteract effects.     

A Multi-laboratory in Vitro Study to Compare Data from Abbreviated and Pharmacopeial Impactor Measurements for Orally Inhaled Products: a Report of the European Aerosol Group (EPAG)

Fine particle dose (FPD) is a critical quality attribute for orally inhaled products (OIPs). The abbreviated impactor measurement (AIM) concept simplifies its measurement, provided there is a validated understanding of the relationship with the full resolution pharmacopoeial impactor (PIM) data for a given product. This multi-center study compared fine particle dose determined using AIM and PIM for five dry powder inhaler (DPIs) and two pressurized metered-dose inhaler (pMDI) products, one of which included a valved holding chamber (VHC). Reference measurements of FPD_PIM were made by each organization using either the full-resolution Andersen 8-stage non-viable impactor (ACI) or Next Generation Impactor (NGI). FPD_AIM was determined for the same OIP(s) with their choice of abbreviated impactor (fast screening impactor (FSI), fast screening Andersen (FSA), or reduced NGI (rNGI)). Each organization used its validated assay method(s) for the active pharmaceutical ingredient(s) (APIs) involved. Ten replicate measurements were made by each procedure. The upper size limit for FPD_AIM varied from 4.4 to 5.0 μm aerodynamic diameter, depending upon flow rate and AIM apparatus; the corresponding size limit for FPD_PIM was fixed at 5 μm in accordance with the European Pharmacopoeia. The 90% confidence interval for the ratio [FPD_AIM/FPD_PIM], expressed as a percentage, was contained in the predetermined 85–118% acceptance interval for nine of the ten comparisons of FPD. The average value of this ratio was 105% across all OIPs and apparatuses. The findings from this investigation support the equivalence of AIM and PIM for determination of FPD across a wide range of OIP platforms and measurement techniques.     

Chemosyndromes in the lichen genus Teloschistes (Teloschistaceae, Lecanorales)

The secondary metabolites of 150 specimens belonging to 29 species of Teloschistes were analysed with HPLC. Seven anthraquinones were detected of which parietin dominated with minor proportions of emodin, teloschistin, fallacinal and parietinic acid. The depsidones vicanicin, caloploicin, and isofulgidin occurred together with some compounds of unknown identity in varying proportions in T. flavicans, T. peruensis, T. stellatus, and one unnamed taxon. Nine chemosyndromes were found in the genus. Most species had only one chemosyndrome, but T. flavicans s. lat. had six syndromes. The geographical distribution patterns of these chemosyndromes in T. flavicans are discussed as well as the applicability of chemical characters for species delimitation in Teloschistes.     

The NIK protein kinase and C17orf1 genes: chromosomal mapping, gene structures and mutational screening in frontotemporal dementia and parkinsonism linked to chromosome 17

Full exon-intron structures are presented for the NIK serine/threonine protein kinase gene and a novel gene termed C17orf1. By in situ hybridisation and radiation hybrid mapping, a cosmid (cDD-Z) that contains regions of both of these genes has been localised between markers D17S800 and D17S791 at chromosome 17q21. The two genes are thus positional candidates for the mutant locus underlying frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17), a disease for which NIK is also a good biological candidate. Using exon-intron maps, a genomic DNA sequencing based mutation screen has been performed for the NIK and C17orf1 genes in a chromosome 17-linked FTDP-17 pedigree. Two silent single-base variations were detected in C17orf1. No alterations were restricted to DNA samples from patients, thus excluding the C17orf1 and NIK genes as likely sites of mutation FTDP-17. Received: 23 December 1997 / Accepted: 23 June 1998