A History of Abuse and Operative Delivery – Results from a European Multi-Country Cohort Study

Objective

The main aim of this study was to assess whether a history of abuse, reported during pregnancy, was associated with an operative delivery. Secondly, we assessed if the association varied according to the type of abuse and if the reported abuse had been experienced as a child or an adult.

Design

The Bidens study, a cohort study in six European countries (Belgium, Iceland, Denmark, Estonia, Norway, and Sweden) recruited 6724 pregnant women attending routine antenatal care. History of abuse was assessed through questionnaire and linked to obstetric information from hospital records. The main outcome measure was operative delivery as a dichotomous variable, and categorized as an elective caesarean section (CS), or an operative vaginal birth, or an emergency CS. Non-obstetrically indicated were CSs performed on request or for psychological reasons without another medical reason. Binary and multinomial regression analysis were used to assess the associations.

Results

Among 3308 primiparous women, sexual abuse as an adult (≥18 years) increased the risk of an elective CS, Adjusted Odds Ratio 2.12 (1.28–3.49), and the likelihood for a non-obstetrically indicated CS, OR 3.74 (1.24–11.24). Women expressing current suffering from the reported adult sexual abuse had the highest risk for an elective CS, AOR 4.07 (1.46–11.3). Neither physical abuse (in adulthood or childhood <18 years), nor sexual abuse in childhood increased the risk of any operative delivery among primiparous women. Among 3416 multiparous women, neither sexual, nor emotional abuse was significantly associated with any kind of operative delivery, while physical abuse had an increased AOR for emergency CS of 1.51 (1.05–2.19).

Conclusion

Sexual abuse as an adult increases the risk of an elective CS among women with no prior birth experience, in particular for non-obstetrical reasons. Among multiparous women, a history of physical abuse increases the risk of an emergency CS.     

Identification of Metabolic Pathways Essential for Fitness of Salmonella Typhimurium In Vivo

Bacterial infections remain a threat to human and animal health worldwide, and there is an urgent need to find novel targets for intervention. In the current study we used a computer model of the metabolic network of Salmonella enterica serovar Typhimurium and identified pairs of reactions (cut sets) predicted to be required for growth in vivo. We termed such cut sets synthetic auxotrophic pairs. We tested whether these would reveal possible combined targets for new antibiotics by analyzing the performance of selected single and double mutants in systemic mouse infections. One hundred and two cut sets were identified. Sixty-three of these included only pathways encoded by fully annotated genes, and from this sub-set we selected five cut sets involved in amino acid or polyamine biosynthesis. One cut set (asnA/asnB) demonstrated redundancy in vitro and in vivo and showed that asparagine is essential for S. Typhimurium during infection. trpB/trpA as well as single mutants were attenuated for growth in vitro, while only the double mutant was a cut set in vivo, underlining previous observations that tryptophan is essential for successful outcome of infection. speB/speF,speC was not affected in vitro but was attenuated during infection showing that polyamines are essential for virulence apparently in a growth independent manner. The serA/glyA cut-set was found to be growth attenuated as predicted by the model. However, not only the double mutant, but also the glyA mutant, were found to be attenuated for virulence. This adds glycine production or conversion of glycine to THF to the list of essential reactions during infection. One pair (thrC/kbl) showed true redundancy in vitro but not in vivo demonstrating that threonine is available to the bacterium during infection. These data add to the existing knowledge of available nutrients in the intra-host environment, and have identified possible new targets for antibiotics.     

Calprotectin and Platelet Aggregation in Patients with Stable Coronary Artery Disease

BackgroundRecent studies suggest that the inflammation-associated protein calprotectin may be implicated in the pathogenesis of coronary artery disease (CAD). However, the impact of calprotectin levels on platelet aggregation in CAD patients has never been investigated.ObjectivesWe investigated the association between calprotectin levels and platelet aggregation in stable, high-risk CAD patients receiving aspirin as mono antiplatelet therapy. Furthermore, we aimed to investigate independent clinical and laboratory determinants of calprotectin levels.MethodsWe performed a cross-sectional study including 581 stable, high-risk CAD patients. All patients received 75 mg aspirin daily as mono antiplatelet therapy. Platelet aggregation was assessed by 1) impedance aggregometry (Multiplate Analyzer) using arachidonic acid (AA) and collagen as agonists and by 2) the VerifyNow Aspirin Assay. Low-grade inflammation was evaluated by calprotectin, high-sensitive C-reactive-protein (hs-CRP) and interleukin-6. Platelet activation was assessed by soluble P-selectin, and cyclooxygenase-1 inhibition was evaluated by serum thromboxane B₂, both measured by ELISA.ResultsCalprotectin levels correlated positively with platelet aggregation according to Multiplate Analyzer (r=0.12, p=0.01). Additionally, calprotectin was positively associated with leukocytes (r=0.33, p<0.0001), hs-CRP (r=0.31, p<0.0001), interleukin-6 (r=0.28, p<0.0001), soluble P-selectin (r=0.10, p=0.02) and serum thromboxane B₂ (r=0.10, p=0.02). Type 2 diabetes mellitus was an independent predictor of increased calprotectin levels (p=0.004), and trends were seen for body mass index (p=0.06) and smoking (p=0.07). Compliance with aspirin was confirmed by low serum thromboxane B₂ levels in all patients (median [25%;75%]: 1.07 [0.52;1.87] ng/mL).ConclusionCalprotectin levels correlated positively, though weakly, with platelet aggregation and activation as well as serum thromboxane B₂ in high-risk, stable CAD patients treated with aspirin.     

Decreased heart rate variability in HIV positive patients receiving antiretroviral therapy: importance of blood glucose and cholesterol

The presence of autonomic dysfunction in HIV patients is largely unknown. Early studies found autonomic dysfunction in patients with AIDS. Antiretroviral combination therapy (ART) has dramatically changed the course of the disease and improved prognosis and decreased morbidity.

Aim

To evaluate whether autonomic dysfunction is present in an ART treated HIV population and if so to identify factors of importance.

Methods

HIV patients receiving ART for at least 12 months (n = 97) and an age-matched control group of healthy volunteers (n = 52) were included. All were non-diabetic and had never received medication for hypertension. Following a 10 min resting period a 15 min ECG recording was performed. Heart-rate variability (HRV) analysis was performed in accordance with current guidelines and data reported as mean [interquartile range].

Results

Mean normal-to-normal (NN) and total HRV measured as standard deviation of normal-to-normal (SDNN) was lower in HIV patients compared to controls (905 vs. 982 ms; p<0.001 and 48 vs. 54 ms; p = 0.028, respectively). No differences were found between the groups in parasympathetic activity measured as square root of the mean squared difference of successive NN-intervals (RMSSD) or the percent of differences between adjacent NN intervals greater than 50 ms (pNN50). In the HIV positives, haemoglobin A1c correlated inversely with SDNN, RMSSD and pNN50 (p<0.05). Total cholesterol and LDL-C correlated inversely with RMSSD and pNN50 (p<0.05). Neither HIV duration, HIV-RNA, CD4 cell count nor CD4 nadir correlated with time or phase domain HRV variables.

Conclusions

Moderate autonomic dysfunction is present in HIV positives patients even with suppressed viral load due to ART. The dysfunction is correlated with HbA1c and hypercholesterolemia but not to duration of HIV or whether the patients were receiving protease inhibitors as part of the ART regime.     

Polymerase chain reaction in diagnosis of Borrelia burgdorferi infections and studies on taxonomic classification

Lyme borreliosis caused by the spirochete Borrelia burgdorferi is now the most common vectorborne disease in North America, Europe and Asia. It is a multisystemic infection which may cause skin, neurological, cardiac or rheumatologic disorders. The aims of the present thesis were: (i) to develop a PCR assay for direct detection of B. burgdorferi DNA and to evaluate the diagnostic utility of PCR in clinical specimens from patients with Lyme borreliosis and (ii) to study the taxonomic classification of B. burgdorferi isolates and its implications for epidemiology and clinical presentation. Laboratory diagnosis of Lyme borreliosis by direct demonstration of B. burgdorferi in clinical specimens would compared to current serology allow (i) optimal specificity, (ii) increased sensitivity during the first weeks of infection, when the antibody response is not yet detectable and (iii) discrimination between ongoing and past infection. Due to the extreme paucity of spirochetes in clinical specimens neither in vitro culture nor antigen detection had yielded a sufficient diagnostic sensitivity. Thus the recently introduced highly sensitive PCR methodology could be a solution and was thus studied. Assays for PCR amplification and subsequent identification of B. burgdorferi specific sequences were established and used. For all assays the analytical sensitivity was a few genome copies using purified DNA as template. The efficacy of PCR was initially evaluated using tissue samples from experimentally infected gerbils in order to start with biological samples a priori known to contain B. burgdorferi. B. burgdorferi DNA was detectable in 88% of the specimens. Thus the diagnostic sensitivity of PCR was comparable to and even higher than in vitro culture. PCR was significantly more sensitive than a histological B. burgdorferi specific immunophosphatase-staining method. The utility of the PCR was then tested for identification of B. burgdorferi DNA in skin biopsies from 31 patients with erythema migrans. The sensitivity of PCR was 71%, which was superior to culture and serology. Based on own and otherwise published results there is clear evidence for PCR being the most sensitive and specific test for detection of B. burgdorferi in skin biopsies from patients with both early and late dermatoborreliosis. However, since the clinical diagnosis of dermatoborreliosis in most instances is easy, an invasive procedure as a skin biopsy, will only be justified in patients with an atypical clinical presentation. The most frequent and serious manifestation of disseminated Lyme borreliosis is neuroborreliosis. PCR was applied to 190 patients with untreated and confirmed neuroborreliosis. B. burgdorferi DNA was detectable in 17-21% of CSF samples from patients with neuroborreliosis. In patients with very early neuroborreliosis (< 2 weeks), still being negative for specific intrathecal antibody synthesis, a positive PCR was more frequent than in patients with longer disease duration. PCR can be used as a diagnostic aid in these patients. However, in general the measurement of specific intrathecal antibody production in patients with neuroborreliosis was superior to PCR. In urine samples from patients with Lyme borreliosis the diagnostic sensitivity varied, generally showing a low reproducibility. Urine is thus not regarded as a suitable sample source for B. burgdorferi PCR. The reason may be the variable presence of Taq polymerase inhibitors. Based on a semi-quantitative detection system for amplicons, reflecting the input amount of specific DNA and thus the density of spirochetes in the clinical samples high amounts of DNA were found in skin biopsies whereas especially in urine the amount of DNA was low. When the present study was initiated there was no accepted classification of B. burgdorferi. A heterogeneity among B. burgdorferi strains might have important implications for understanding the epidemiology and different clinical presentations (dermatoborreliosis versus neuroborreliosis) and courses (self-limiting versus chronic disease). Furthermore, strain differences were of importance for selection of suitable antigens for diagnostic assays and for vaccine development. Since then, B. burgdorferi isolates have been studied by phenotypic and genotypic traits and have been shown to be highly heterogeneous. Our first approach was to genotype a panel of human B. burgdorferi isolates by restriction fragment length polymorphism (RFLP) of three genes. Thereafter, sequencing and dideoxy fingerprinting of ospA was applied. By RFLP the strains could be differentiated into two to five groups. The RFLP classification was compared with four different phenotypic and genotypic methods including the rRNA typing. Results obtained with the different methods correlated highly and confirmed the meanwhile accepted taxonomic classification by Baranton et al., According to this the term B. burgdorferi sensu lato comprises three different human pathogenic genospecies B. burgdorferi sensu stricto, B. garinii and B. afzelii. All three genospecies have been isolated among Danish patients with Lyme borreliosis and are thus prevalent in Denmark. Since isolation of B. burgdorferi from patients with Lyme borreliosis is laborious and often unsuccessful molecular typing methods based on PCR are recommended obviating the need for isolation by prior culture. Of special interest was to study a possible association of neuroborreliosis to certain B. burgdorferi genospecies, indicating species depended organotropism. By RFLP all six CSF isolates tested belonged to B. garinii and that 6 out of 7 isolates from patients with acrodermatitis chronica atrophicans belonged to B. afzelii. Due to the low culture yield of B. burgdorferi from CSF, the association of B. garinii and neuroborreliosis was further studied by sequence analysis and dideoxyfingerprinting analysis of ospA PCR amplicons obtained from CSF samples from patients with neuroborreliosis. Phylogenetic analysis showed that in 11 out of 13 patients B. garinii DNA was found in CSF. These data strongly supports the hypothesis that B. garinii is the principal agent of Lyme neuroborreliosis in Europe. Similarly it was shown that B. afzelii is associated with acrodermatitis chronica atrophicans and thus dermatoborreliosis. Due to a strain dependent different selection pressure in culture only PCR based methods can be used to answer whether mixed infection in patients specimens occur. Our data indicate that mixed infections in humans if ever are rare.     

Food limitation in a wild cyclopoid copepod population: direct and indirect life history responses

We studied the effects of food limitation on the population dynamics of the freshwater cyclopoid copepod Diacyclops thomasi in Oneida Lake, New York. In the field population, maximum juvenile abundance coincided seasonally with high phytoflagellate concentration. During the clear-water phase (a seasonal period of low algal density), D. thomasi disappeared from the water column, but fourth-instar copepodids (CIV) were found encysted in developmental arrest in the sediment. Laboratory assays of the effect of the density of two types of food on copepod life history parameters showed that temporal variation in the concentration of relatively small phytoflagellates significantly affected stage-specific development times. This food limitation was most pronounced during the clear-water phase, and supplementation of the diet with a laboratory-cultured phytoflagellate, Chlamydomonas, prevented food limitation. Although developmental arrest appears to be controlled primarily by photoperiod, availability of the larger, more mobile food, Euglena, also influenced the percentage of individuals entering developmental arrest in the laboratory. An investigation of the spatial and temporal emergence pattern in the field revealed that CIV copepodids started to emerge in late autumn and that emergence rates were significantly greater at deep-water locations (9–12 m water depth) compared with shallow-water locations (5–7 m). The clear-water phase in Oneida Lake is an annual event, probably produced by intense grazing by Daphnia pulicaria and Daphnia galeata. Food limitation is thus very likely a recurrent phenomenon for D. thomasi. This apparent seasonal competitive impact of Daphnia on Diacyclops affects both nauplii and immature copepodids. Diacyclops shows two types of responses to the food limitation: (1) the physiological response of slowed active development, and (2) the adaptive response of developmental arrest. Received: 3 November 1997 / Accepted: 1 March 1998     

Algal 14C and total carbon metabolisms. 2. Experimental observations with the diatom Skeletonema costatum

Three sets of comparisons of net and gross inorganic carbonassimilation and ¹⁴C uptake were made with an axenic cultureof Skdetonema costatum. The comparisons showed that in the physiologicalwindow studied (10–20% of the intrinsic generation timeand gross photosynthesis/respiration ratios of 2–3), ¹⁴Cuptake into the paniculate plus the dissolved fractions approximatedto net photosynthesis. Rate constants derived from the chemicallydetermined changes were used to parameterize models that accountedfor the respiration of photosynthetic products and for the recyclingof respiratory CO₁₄. The conclusion drawn was that over thetime scale studied, the ¹⁴C technique was measuring net photosynthesis,consistent with essentially 100% recycling of respiratory CO₂.The study has shown that we now possess the basis to make arigorous analysis of net, gross CC₄ fixation and net ¹⁴C uptake,and forms the first step in the development of algorithms forthe interpretation of ¹⁴C field observations.     

Stimulating soil microorganisms for mineralizing the herbicide isoproturon by means of microbial electroremediating cells

The absence of suitable terminal electron acceptors (TEA) in soil might limit the oxidative metabolism of environmental microbial populations. Microbial electroremediating cells (MERCs) consist in a variety of bioelectrochemical devices that aim to overcome electron acceptor limitation and maximize metabolic oxidation with the purpose of enhancing the biodegradation of a pollutant in the environment. The objective of this work was to use MERCs principles for stimulating soil bacteria to achieve the complete biodegradation of the herbicide ¹⁴C‐isoproturon (IPU) to ¹⁴CO₂ in soils. Our study concludes that using electrodes at a positive potential [+600 mV (versus Ag/AgCl)] enhanced the mineralization by 20‐fold respect the electrode‐free control. We also report an overall profile of the ¹⁴C‐IPU metabolites and a ¹⁴C mass balance in response to the different treatments. The remarkable impact of electrodes on the microbial activity of natural communities suggests a promising future for this emerging environmental technology that we propose to name bioelectroventing.     

Conversion of solvent evaporation residues from the AB- (acetone-butanol) bioprocess into bacterial cells accumulating thermoplastic polyesters

In a bioconversion study based on utilisation of by-products from the AB- (acetone-butanol) bioprocess a new isolated gram-negative solvent tolerant bacterium was used to convert the AB process residue after removal of the major part of the solvents. The bacterium identified as a representative of the genus Alcaligenes (designated as Alcaligenes sp. G) was capable of growth up to optical densities ranging from 8 to 20 and simultaneously of polyhydroxyalkanoate- (PHA-)accumulation up to 40% per dry weight. A standardised medium based on AB by-products containing 7 g/l of butyrate and 5 g/l of acetate at pH 7.5 was used in our studies for bioconversion into PHAs. Concentrations of 1-butanol, which is known for its membrane damaging properties in micro-organisms, were tolerated in the AB by-products medium up to 4 g/l without significant inhibition of cellular growth. No inhibition of growth was observed, when the medium was adjusted to 40 g/l butyrate. Due to the toxicity of the remaining 1-butanol maintenance of sterility is of no high priority during the process. The use of acetate and butyrate from an AB process is expected to provide a higher return-on-investment than the combustion of biogas to help meet energy demands.     

Diel changes in dark respiration in a plankton community

The dark respiration of a natural plankton community from an eutrophic lake was studied in a laboratory scale enclosure (LSE), exposed to illumination which simulated natural light conditions in the water column. The dark respiration was measured continuously for 2 hours in samples obtained from the LSE each hour for 26 hours. The relationships between dark respiration rates, carbohydrate concentrations and other parameters were investigated.The dark respiration rate showed an exponential decrease with time in the dark in all light period incubations with a time coefficient of 0.3 h^–1. The decrease in respiration rate in the dark period was much slower, reaching an approximately constant level at the end of the night. The overall dark period decline in respiration rate also exhibited an exponential pattern, but with a much lower time coefficient (0.04 h ^–1) than for the light period incubations. A linear relationship was found between dark respiration rate and carbohydrate concentration at night time but no relationship was apparent during the day. A comparison between these data and data from the literature show that this pattern of dark respiration rate decrease with time in the dark may have some general applications for dense phytoplankton communities.