Lars Ditlev Mørck Ottosen

Stressful life events are associated with a poor in-vitro fertilization (IVF) outcome: a prospective study

BACKGROUND There is preliminary evidence to suggest an impact of stress on chances of achieving a pregnancy with in-vitro fertilization (IVF). The majority of the available research has focused on stress related to infertility and going through IVF-treatment, and it is still unclear whether non-fertility-related, naturally occurring stressors may influence IVF pregnancy chances. Our aim was to explore the association between IVF-outcome and negative, i.e. stressful, life-events during the previous 12 months. METHODS Prior to IVF, 809 women (mean age: 31.2 years) completed the List of Recent Events (LRE) and questionnaires measuring perceived stress and depressive symptoms. RESULTS Women who became pregnant reported fewer non-fertility-related negative life-events prior to IVF (Mean: 2.5; SD: 2.5) than women who did not obtain a pregnancy (Mean: 3.0; SD: 3.0) (t(465.28) = 2.390, P = 0.017). Logistic regression analyses revealed that the number of negative life-events remained a significant predictor of pregnancy (OR: 0.889; P = 0.02), when controlling for age, total number of life-events, perceived stress within the previous month, depressive symptoms, and relevant medical factors related to the patient or treatment procedure, including duration of infertility, number of oocytes retrieved and infertility etiology. Mediation analyses indicated that the association between negative life events and IVF pregnancy was partly mediated by the number of oocytes harvested during oocyte retrieval. CONCLUSION A large number of life-events perceived as having a negative impact on quality of life may indicate chronic stress, and the results of our study indicate that stress may reduce the chances of a successful outcome following IVF, possibly through psychobiological mechanisms affecting medical end-points such as oocyte retrieval outcome.

Improved nitrogen removal by application of new nitrogen-cycle bacteria

In order to meet increasingly stringentEuropean discharge standards, new applicationsand control strategies for the sustainableremoval of ammonia from wastewater have to beimplemented. In this paper we discuss anitrogen removal system based on the processesof partial nitrification and anoxic ammoniaoxidation (anammox). The anammox process offersgreat opportunities to remove ammonia in fullyautotrophic systems with biomass retention. Noorganic carbon is needed in such nitrogenremoval system, since ammonia is used aselectron donor for nitrite reduction. Thenitrite can be produced from ammonia inoxygen-limited biofilm systems or in continuousprocesses without biomass retention. Forsuccessful implementation of the combinedprocesses, accurate biosensors for measuringammonia and nitrite concentrations, insight inthe complex microbial communities involved, andnew control strategies have to be developed andevaluated.

Light exposure of the ovum and preimplantation embryo during ART procedures

Exposure to visible light (400–700 nm wavelengths) is an unnatural stress factor to preimplantation embryos cultured in vitro. This study investigated the spectral composition and intensity of light during IVF procedures, and calculated radiation doses reaching the embryo during handling and manipulation. The study shows that normal IVF procedure may result in stressing radiation doses, unless filters are applied. This is at present not sufficiently recognised. No Danish IVF clinics use filters to protect embryos against visible light. 95% of the radiation was from microscopes. Ambient light, in contrast, was not a significant contributor to light stress and the use of dark laboratories is not justified.

Pregnancy prediction models and eSET criteria for IVF patients–do we need more information?

Purpose: The purpose of the present study was to evaluate statistical prediction models and simple allocation criteria, based on predictors for pregnancy, as tools to identify a good prognosis group in a possible eSET setting.Methods: A pregnancy prediction model based on logistic regression models was generated by analysis of 1675 DET treatment cycles. The model was evaluated and compared to simple eSET allocation criteria.Results: Embryo quality, patient age, and basal FSH were identified as significant predictors (at 5% significance level) of pregnancy. Although comparable to previously generated models, the predictive ability of the present model was relatively poor and practically similar to simple allocation criteria based on age and embryo quality.Conclusions: Existing prediction models, or simple allocation criteria, are limited in identifying good prognosis patients. Future studies of the applicability of improved pregnancy prediction models will need very comprehensive and detailed patient and embryo information.

Observations on intrauterine oxygen tension measured by fibre-optic microsensors

Understanding the biology of reproductive organs is essential for the development of assisted reproductive techniques. There is at present no direct evidence for either the concentration and dynamics of intrauterine oxygen tension at the endometrial surface, nor its importance for the receptiveness of the endometrium. In this study a new method measured mid-cycle (ranging from day 12-18) endometrial surface oxygen tension in 21 patients referred to intrauterine insemination (IUI). Time series was measured online for a period of 5-10 min. The (mean) individual oxygen tension among patients varied from 4 to 27% air saturation. Overall mean oxygen tension among all patients was 11.8% air saturation. Within the same patient, considerable time-related variations were observed. Some patients exhibited rhythmic oscillations with a frequency in the order of 1 min, whereas others did not show any regular patterns. A good description of endometrial surface oxygen concentration and dynamics was thus obtained, but given the relatively small number of participants, an association with pregnancy following insemination could not be established. Further studies using this new method could elucidate the association between individual intrauterine activity, embryo implantation and endometrial surface oxygen tension.

Distribution and Rate of Microbial Processes in an Ammonia-Loaded Air Filter Biofilm

ABSTRACT The in situ activity and distribution of heterotrophic and nitrifying bacteria and their potential interactions were investigated in a full-scale, two-section, trickling filter designed for biological degradation of volatile organics and NH3 in ventilation air from pig farms. The filter biofilm was investigated by microsensor analysis, fluorescence in situ hybridization, quantitative PCR, and batch incubation activity measurements. In situ aerobic activity showed a significant decrease through the filter, while the distribution of ammonia-oxidizing bacteria (AOB) was highly skewed toward the filter outlet. Nitrite oxidation was not detected during most of the experimental period, and the AOB activity therefore resulted in NO2−, accumulation, with concentrations often exceeding 100 mM at the filter inlet. The restriction of AOB to the outlet section of the filter was explained by both competition with heterotrophic bacteria for O2 and inhibition by the protonated form of NO2−, HNO2. Product inhibition of AOB growth could explain why this type of filter tends to emit air with a rather constant NH3 concentration irrespective of variations in inlet concentration and airflow.

BOLD MRI in sheep fetuses: a non-invasive method for measuring changes in tissue oxygenation.

The purpose of this descriptive study was to correlate changes in the blood oxygen level‐dependent (BOLD) magnetic resonance imaging (MRI) signal with direct measurements of fetal tissue oxygenation.

In situ measurements of photosynthetic activity and respiration of intertidal benthic microalgal communities undergoing vertical migration

Abstract This paper presents the results of a field study on the short-term variability in photosynthetic activity of inter-tidal microphytobenthos using non-destructive techniques in situ. Photosynthetic rate (measured using oxygen microelectrodes), productive biomass and photosynthetic efficiency (dark-fluorescence and effective quantum efficiency of PSII, respectively, measured by PAM fluorometry) were measured in situ during a low-tide exposure period on an intertidal mudflat in the Tagus Estuary, Portugal. Community photosynthesis displayed large temporal variation. Maximum activity (24.3 mmol O2 m-2 h-1) was found at noon while minimum activity (8.7 mmol O2 m-2 h-1) was found at the end of the exposure period. Productive biomass followed a similar pattern. During the course of the exposure period, productive biomass peaked halfway through, and decreased by 80% towards the end of the exposure period. These changes in productive biomass were followed by significant changes in the species composition/cell size as well as changes in photosynthetic efficiency of the microphytobenthic community in the surface sediment. The obtained results therefore suggest that microphytobenthic community-level photosynthesis is controlled by migratory movements of microalgae and by variations in photosynthetic efficiency. The latter could be induced by changes in the species composition/cell size in the photic zone due to microalgal migrations. It is suggested that the migration pattern and, hence, photosynthesis is linked to changes in salinity, temperature and light, changes that are difficult to simulate accurately in the laboratory. Respiration rates obtained during the day were much higher than those obtained at night, and also displayed a marked hour-to-hour variation. Depth integrated respiration within the photosynthesis zone (0.33 mm) represented 80 to 90% of the respiration in the entire oxic zone, suggesting a tight coupling between photosynthesis and respiration.

In-situ biogas upgrading with pulse H2 additions: The relevance of methanogen adaption and inorganic carbon level

Surplus electricity from fluctuating renewable power sources may be converted to CH4 via biomethanisation in anaerobic digesters. The reactor performance and response of methanogen population of mixed-culture reactors was assessed during pulsed H2 injections. Initial H2 uptake rates increased immediately and linearly during consecutive pulse H2 injections for all tested injection rates (0.3 to 1.7LH2/Lsludge/d), while novel high throughput mcrA sequencing revealed an increased abundance of specific hydrogenotrophic methanogens. These findings illustrate the adaptability of the methanogen population to H2 injections and positively affects the implementation of biomethanisation. Acetate accumulated by a 10-fold following injections exceeding a 4:1 H2:CO2 ratio and may act as temporary storage prior to biomethanisation. Daily methane production decreased for headspace CO2 concentrations below 12% and may indicate a high sensitivity of hydrogenotrophic methanogens to CO2 limitation. This may ultimately decide the biogas upgrading potential which can be achieved by biomethanisation.

Removal of antibiotics during the anaerobic digestion of pig manure

Antibiotics are frequently used in animals to treat sickness and prevent infection especially in industrial meat production. Some of the antibiotics cannot be completely metabolized and, as an unavoidable result, are excreted and thus end up in manure which is then spread in the environment. Currently increasing amounts of manure is used in biogas production before spreading the residuals on agricultural fields. In this study, the removal patterns of sulfonamides (sulfadiazine, sulfamethizole, sulfamethoxazole) and macrolides (clarithromycin, erythromycin), as well as trimethoprim, were investigated during the anaerobic digestion of pig manure. Batch kinetic tests were conducted both at thermophilic and psychrophilic condition for 40 days. Some of the antibiotics (clarithromycin, sulfadiazine, sulfamethizole) were persistent in all experiments. Thus, no biodegradation was found for sulfadiazine and sulfamethizole in this study. From the studied compounds, only erythromycin was clearly removed and probably degraded during anaerobic digestion with 99% and 20% removal under thermophilic and psychrophilic condition. The removal of erythromycin was fitted to a single first-order kinetic reaction function, giving reaction rate constant of 0.29day-1 and 0.005day-1, respectively.