Determinants of female fecundity in a simultaneous hermaphrodite: the role of polyandry and food availability

Classical sexual selection theory assumes that the reproductive success of females is primarily limited by the resources available for egg production rather than by the number of mating partners. However, there is now accumulating evidence that multiple mating can entail fitness costs or benefits for females. In this study we investigated the effect of polyandry (i.e., the mating with different mating partners) and food availability on the reproductive output of the female sex function in an outcrossing simultaneous hermaphrodite, the free-living flatworm Macrostomum lignano. We exposed virgin worms to different group sizes, a treatment that has previously been shown to affect the level of polyandry in this species. Moreover, we manipulated the food availability throughout the subsequent egg laying period, during which the worms were kept in isolation. The number of offspring produced was used as an estimate of female fecundity. We found that food availability, but not group size, had a significant effect on female fecundity. Additionally, female fecundity was positively correlated with the number of stored sperm in the female sperm-storage organ at the time of isolation, but it was not correlated with body or ovary size of the worms. Our results suggest that female fecundity in M.lignano is primarily determined by the resources available for egg production, and not by the level of polyandry, confirming classic sexual selection theory for simultaneous hermaphrodite

cGMP at the centre of attention: emerging strategies for activating the cardioprotective PKG pathway.

The nitric oxide (NO)-protein kinase G (PKG) pathway has been known for some time to be an important target for cardioprotection against ischaemia/reperfusion injury and heart failure. While many approaches for reducing infarct size in patients have failed in the past, the advent of novel drugs that modulate cGMP and its downstream targets shows very promising results in recent preclinical and clinical studies. Here, we review main aspects of the NO-PKG pathway in light of recent drug development and summarise potential cardioprotective strategies in which cGMP is the main player

Induction of VEGF and VEGF receptor gene expression by hypoxia: Divergent regulation in vivo and in vitro

Induction of VEGF and VEGF receptor gene expression by hypoxia: Divergent regulation in vivo and in vitro. This study examined the expression of EPO,VEGF and VEGF receptor gene under conditions of reduced oxygen supply in primary cultures of rat hepatocytes, and compared it with the expression of these genes in hypoxic rat livers in vivo. To this end we exposed male Sprague-Dawley rats to hypoxia (10% and 8% O2), carbon monoxide (0.1% CO) or injected cobalt chloride (60 mg/kg CoCl2) subcutaneously. For the in vitro experiments we used primary cultures of rat hepatocytes which were kept at high (20% O2) and low (1% O2) oxygen tensions for three hours. The EPO mRNA was up-regulated by hypoxia in vitro and in vivo about 10-fold. The VEGF mRNA was up-regulated fivefold in the hepatocytes only, whereas the in vivo mRNA levels remained unchanged. The mRNA levels of flt-1 were up-regulated threefold by 8% O2 in livers, dependent on the strength of hypoxia (10% caused no changes in flt-1 gene expression) and on the kind of hypoxic stimulus (8% O2 was as effective as 0.1% CO and more effective than cobalt). The mRNA levels of flk-1/KDR and flt-4 remained unchanged in the liver. In vitro there were no changes in the mRNA levels of flt-1, flt-4 and flk-1/KDR. Consequently, the in vivo regulation of VEGF, which might be modulated by induction of flt-1 receptor gene expression, differs from the in vitro cell culture situation and might be different from the EPO regulationin viv

RFID-Based Media Usage Panels in Real-World Settings

Traditional paper-based longitudinal or cross section panel surveys, used for market research are time and cost consuming and can suffer from contaminating effects like social desirability bias or respondent conditioning. Electronic data capture methods can improve the time and cost efficiency of market research panels. Radio Frequency Identification (RFID) technology allows a seamless and non-intrusive integration of information systems into everyday life environments. This enables the automated electronic acquisition of media usage data, without direct interference with the media consumption and thus without the contaminating effects of traditional panel surveys. Consequently, we introduce an RFID-based prototype system called MUSE (Media Usage in Supportive Environments) that supports automatic measurements of print media usage in public environments. MUSE was tested in an initial field study over the course of six weeks in the waiting room of a German medical practice. The study showed that MUSE could monitor the usage of print media, laid out for waiting patients, autonomously and with minimal errors. Furthermore, the RFID technology was perceived as nonintrusive. This study is the first to show how RFID enhanced real world settings can be used for nonintrusive media usage analysis in real life. Based on the findings we derive recommendations for future research for RFID supported media usage analysis

Protein Kinase G Is Involved in Acute but Not in Long-Term Regulation of Renin Secretion

Pharmacological inhibition of the renin-angiotensin-aldosterone system (RAAS) is, in combination with diuretics, the first-choice treatment for hypertension, although 10-20% of patients do not respond adequately. Next to the RAAS, the nitric oxide/cGMP/protein kinase G (PKG) system is the second fundamental blood pressure regulator. Whether both systems influence each other is not well-studied. It has been shown that nitric oxide (NO) supports renin recruitment via activation of soluble guanylate cyclase (sGC) and subsequent generation of cGMP. Whether this leads to an ensuing activation of PKGs in this context is not known. PKGI alpha, as well as PKGII, is expressed in renin-producing cells. Hence, we analyzed whether these enzymes play a role regarding renin synthesis, secretion, or recruitment. We generated renin-cell-specific PKGI-knockout mice and either stimulated or inhibited the renin system in these mice by salt diets. To exclude the possibility that one kinase isoform can compensate the lack of the other, we also studied double-knockout animals with a conditional knockout of PKGI in juxtaglomerular cells (JG cells) and a ubiquitous knockout of PKGII. We analyzed blood pressure, renin mRNA and renal renin protein content as well as plasma renin concentration. Furthermore, we stimulated the cGMP system in these mice using BAY 41-8543, an sGC stimulator, and examined renin regulation either after acute administration or after 7 days (application once daily). We did not reveal any striking differences regarding long-term renin regulation in the studied mouse models. Yet, when we studied the acute effect of BAY 41-8543 on renin secretion in isolated perfused kidneys as well as in living animals, we found that the administration of the substance led to a significant increase in plasma renin concentration in control animals. This effect was completely abolished in double-knockout animals. However, after 7 days of once daily application, we did not detect a persistent increase in renin mRNA or protein in any studied genotype. Therefore, we conclude that in mice, cGMP and PKG are involved in the acute regulation of renin release but have no influence on long-term renin adjustment

Selective phosphodiesterase-5 inhibition reduces neointimal hyperplasia in rat carotid arteries after surgical endarterectomy.

OBJECTIVE: Long-term results of surgical vessel reconstruction are compromised by restenosis caused by neointimal hyperplasia. Recent studies suggest that reduced cyclic guanosine monophosphate signaling is associated with neointima formation. In a rat model of endarterectomy, we investigated the effect of pharmacologic inhibition of cyclic guanosine monophosphate degradation on neointima formation by using the selective phosphodiesterase-5 inhibitor vardenafil. METHODS: Carotid endarterectomy was performed in male Sprague-Dawley rats by means of incision of the right common carotid artery with removal of intima. Four groups were studied: unoperated control rats (n = 4), sham-operated rats (n = 9), control rats with endarterectomy (n = 9), or endarterectomized rats treated with vardenafil (10 mg/kg/day) postoperatively (n = 9). After 3 weeks, vessel compartment areas were measured by means of conventional microscopy with hematoxylin and eosin staining. Immunohistochemical analysis was performed to confirm neointima formation and the local cyclic guanosine monophosphate content. Plasma levels of cyclic guanosine monophosphate were determined by means of enzyme immunoassay. Student's t test was used for statistical evaluation. RESULTS: Immunohistochemical analysis demonstrated intensive staining for transforming growth factor beta1 and alpha-smooth muscle actin in the control neointima. Vardenafil significantly reduced the stenosis grade (24.64% +/- 7.46% vs 54.12% +/- 10.30% in the control group, P < .05) and expression of transforming growth factor beta1, as well as alpha-smooth muscle actin, in the neointima. The immunohistochemical score for cyclic guanosine monophosphate was higher in the treated neointima (4.80 +/- 0.76 vs 2.84 +/- 0.40 in the control group, P < .05), and increased plasma cyclic guanosine monophosphate levels were found by means of enzyme immunoassay as well (84.65 +/- 12.77 pmol/mL vs 43.50 +/- 3.30 pmol/mL in the control group, P < .05). CONCLUSIONS: Treatment with vardenafil can be considered a new possibility to prevent neointimal hyperplasia after endarterectomy

Machbarkeitstudie für einen industriellen supraleitenden Table Top Elektronenbeschleuniger

At the Forschungszentrum Rossendorf the build-up of the superconducting 1.3 GHz accelerator ELBE is still in progress. Furthermore a new sc photo injector (SRF gun) is under development, which should accelerate electrons up to 10 MeV at 1.3 GHz frequency. The use of electron accelerators is also more and more interesting for applications where the destructive potential of the electrons are used like sterilization of medical waste and medical products, food irradiation or decontamination of sewage. For these processes a high power is required to achieve a high product throughput in a plant. The aim is therefore to use beam powers of around 100 kW or more. Since the applications of electron accelerators in industrial environments are steadily increasing one can speculate about transferring the above named state of the arte technology to industrial electron accelerators. At the FZR a feasibility study of such a table top electron accelerator (TTE) has been performed to investigate its technical limits and marketabilitys