Comparison of cardioprotective effects using ramipril and DanShen for the treatment of acute myocardial infarction in rats

In the present study, we compared cardioprotective effects of DanShen (an extract from Salvia miltiorrhiza) and the angiotensin-converting enzyme inhibitor, ramipril, in rats. With both treatment regimens, DanShen- and ramipril similar effects were observed: (1) a higher survival rate, (2) a significant reduction of infarct size, (3) significantly lower ratios of heart weight to the body weight as well as the left and right ventricular weights to body weight. DanShen showed some unique effects in the following aspects: (1) higher activities of antioxidant defense enzymes such as superoxide dismutase (SOD), catalase (CAT), glutatione perioxidase (GSH-Px) and glutathione S-transferase (GST) in the liver of rats with acute myocardial infarction (AMI), (2) lower myocardial and hepatic TBARS values; (3) augmented VEGF mRNA expressions in the non-ischemic parts of rat hearts with AMI. These results were consistent with the findings of a slight increase in myocardial capillary density and the special distribution pattern of coronary blood vessels in DanShen-treated rats.     

Protection against fatty liver but normal adipogenesis in mice lacking adipose differentiation-related protein

Adipose differentiation-related protein (ADFP; also known as ADRP or adipophilin), is a lipid droplet (LD) protein found in most cells and tissues. ADFP expression is strongly induced in cells with increased lipid load. We have inactivated the Adfp gene in mice to better understand its role in lipid accumulation. The Adfp-deficient mice have unaltered adipose differentiation or lipolysis in vitro or in vivo. Importantly, they display a 60% reduction in hepatic triglyceride (TG) and are resistant to diet-induced fatty liver. To determine the mechanism for the reduced hepatic TG content, we measured hepatic lipogenesis, very-low-density lipoprotein (VLDL) secretion, and lipid uptake and utilization, all of which parameters were shown to be similar between mutant and wild-type mice. The finding of similar VLDL output in the presence of a reduction in total TG in the Adfp-deficient liver is explained by the retention of TG in the microsomes where VLDL is assembled. Given that lipid droplets are thought to form from the outer leaflet of the microsomal membrane, the reduction of TG in the cytosol with concomitant accumulation of TG in the microsome of Adfp-/- cells suggests that ADFP may facilitate the formation of new LDs. In the absence of ADFP, impairment of LD formation is associated with the accumulation of microsomal TG but a reduction in TG in other subcellular compartments.     

Collagen matrix deposition is dramatically enhanced in vitro when crowded with charged macromolecules: the biological relevance of the excluded volume effect

The excluded volume effect (EVE) rules all life processes. It is created by macromolecules that occupy a given volume thereby confining other molecules to the remaining space with large consequences on reaction kinetics and molecular assembly. Implementing EVE in fibroblast culture accelerated conversion of procollagen to collagen by procollagen C-proteinase (PCP/BMP-1) and proteolytic modification of its allosteric regulator, PCOLCE1. This led to a 20-30- and 3-6-fold increased collagen deposition in two- and three-dimensional cultures, respectively, and creation of crosslinked collagen footprints beneath cells. Important parameters correlating with accelerated deposition were hydrodynamic radius of macromolecules and their negative charge density.     

Biodiversity and Biogeography of Chthamalid Barnacles from the North-Eastern Pacific (Crustacea Cirripedia)

The biogeography and ecology of the species of Chthamalus present on the west coast of America are described, using data from 51 localities from Alaska to Panama, together with their zonation on the shore with respect to that of other barnacles. The species present were C. dalli, Pilsbry 1916, C. fissus, Darwin, 1854, C. anisopoma Pilsbry 1916 and four species in the C. panamensis complex. The latter are C. panamensis Pilsbry, 1916, C. hedgecocki, Pitombo & Burton, 2007, C. alani nom. nov. (formerly C. southwardorum Pitombo & Burton, 2007) and C. newmani sp. nov.). These four species were initially separated by enzyme electrophoresis. They could only be partially separated by DNA bar coding but may be separated using morphological characters.     

Spatial and temporal variation in diets of the crabs <Emphasis Type="Italic">Metopograpsus frontalis</Emphasis> (Grapsidae) and <Emphasis Type="Italic">Perisesarma bidens</Emphasis> (Sesarmidae): implications for mangrove food webs

The diets of the mangrove crabs, Metopograpsus frontalis Miers and Perisesarma bidens de Haan, were investigated monthly for 13 months at two Hong Kong mangroves, to examine possible spatial and temporal influences on their feeding ecology. In both species, a higher degree of gut fullness was observed in summer (May–September) than in winter, suggesting a reduction in winter foraging activity. M. frontalis was omnivorous, with animal and plant materials and inorganic sediments being the major food items. P. bidens was detritivorous, with plant materials and inorganic sediment dominating the gut contents. M. frontalis is, therefore, an opportunistic feeder, whilst P. bidens, like many other members of the Sesarmidae, is a detritivore. Some degree of seasonal variation was shown in the diet of M. frontalis (with more algal material in winter) and P. bidens (with more sediments in summer), but diets were similar between sexes in both species. The dietary pattern of M. frontalis also varied between sites. The diets of the crabs, therefore, appear to be a result of the interplay between the seasonal, physical climate and biological factors, especially food availability and the crabs’ ecology. Results suggest that the predatory role of Metopograpsus, which has been poorly studied, is potentially important to estuarine food webs; whilst the trophic importance of sesarmid crabs, such as Perisesarma, especially in mangrove outwelling, should be critically re-evaluated.     

Behavioral motifs and neural pathways coordinating O2 responses and aggregation in C. elegans

BACKGROUND: Simple stimuli can evoke complex behavioral responses coordinated by multiple neural circuits. O(2) is an important environmental variable for most animals. The nematode C. elegans avoids high O(2), and O(2) levels regulate its foraging and aggregation. RESULTS: Here, we dissect aggregation and responses to O(2) gradients into behavioral motifs and show how O(2) responses can promote aggregation. To remain in a group, C. elegans continually modify their movement. Animals whose heads emerge from a group will reverse or turn, thereby returning to the group. Re-entry inhibits further reversal, aiding retention in the group. If an animal's tail exits a group during a reversal, it switches to forward movement, returning to the group. Aggregating C. elegans locally deplete O(2). The rise in O(2) levels experienced by animals leaving a group induces both reversal and turning. Conversely, the fall in O(2) encountered when entering a clump suppresses reversal, turning, and high locomotory activity. The soluble guanylate cyclases GCY-35 and GCY-36, which are expressed in head and tail neurons, promote reversal and turning when O(2) rises. Avoidance of high O(2) is also promoted by the TRP-related channel subunits OCR-2 and OSM-9, and the transmembrane protein ODR-4, acting in the nociceptive neurons ASH and ADL. Both O(2) responsiveness and aggregation can be modified by starvation, but this is regulated by natural variation in the npr-1 neuropeptide receptor. CONCLUSIONS: Our work provides insights into how a complex behavior emerges from simpler behavioral motifs coordinated by a distributed circuit.     

Selective Enhancement of Donor Hematopoietic Cell Engraftment by the CXCR4 Antagonist AMD3100 in a Mouse Transplantation Model

The interaction between stromal cell-derived factor-1 (SDF-1) with CXCR4 chemokine receptors plays an important role in hematopoiesis following hematopoietic stem cell transplantation. We examined the efficacy of post transplant administration of a specific CXCR4 antagonist (AMD3100) in improving animal survival and in enhancing donor hematopoietic cell engraftment using a congeneic mouse transplantation model. AMD3100 was administered subcutaneously at 5 mg/kg body weight 3 times a week beginning at day +2 post-transplant. Post-transplant administration of AMD3100 significantly improves animal survival. AMD3100 reduces pro-inflammatory cytokine/chemokine production. Furthermore, post transplant administration of AMD3100 selectively enhances donor cell engraftment and promotes recovery of all donor cell lineages (myeloid cells, T and B lymphocytes, erythrocytes and platelets). This enhancement results from a combined effect of increased marrow niche availability and greater cell division induced by AMD3100. Our studies shed new lights into the biological roles of SDF-1/CXCR4 interaction in hematopoietic stem cell engraftment following transplantation and in transplant-related mortality. Our results indicate that AMD3100 provides a novel approach for enhancing hematological recovery following transplantation, and will likely benefit patients undergoing transplantation.     

Ecophysiological and morphological parameters related to survival in grass species exposed to an extreme climatic event

An experiment was performed to elucidate interspecific differences in survival time of grass species subjected to an extreme climatic event. We exposed eight grass species to a simulated heat wave in the field ('free air' temperature increase at 11°C above ambient) combined with drought. We determined whether interspecific differences in survival time were related to the responses of the species to the imposed stress or could be explained by their ecophysiological or morphological characteristics in unstressed conditions. Surprisingly, there was no effect of specific leaf area, but species with a higher total leaf area survived longer. This may arise from a greater water reserve in the plant as a whole, which could delay the desiccation of the meristem, or from reduced evaporation due to a higher leaf area index. Species in which the decrease in light-saturated stomatal conductance ( g _s ) and photosynthetic CO₂ uptake rate ( A _max ) was strongly related to the decrease in soil water availability (measured as soil relative water content and stress duration) survived longer than species in which g _s and A _max likewise declined but responded more to daily fluctuations in irradiance, temperature, and vapor pressure deficit during the heat wave. We, therefore, hypothesize that interspecific differences in stress survival time might be related to the extent to which stomata react to changes in soil water conditions relatively to changes in other environmental and physiological factors. The results suggest that resistance to extremes is governed by other mechanisms than resistance to moderate drought.