Is mating of copepods associated with increased risk of predation?

In laboratory experiments, we tested whether the cyclopoid copepodCyclops vicinus is more vulnerable to predation by juvenile(young-of-the-year) roach (Rutilus rutilus) and/or larvae ofthe phantom midge Chaoborus flavicans during mating than individualadult copepods of the same species. We also tested whether C.vicinusavoided mating, displayed shorter mating times and/or loweractivity when a predator (Chaoborus) was present, or when exposedto water in which predators (Chaoborus) were previously held.Fish ate the same quantity of pairs in copulation and individualegg-bearing females but significantly fewer females withouteggs. Chaoborus ate similar quantities of pairs and femalesbut fewer males. Pairs in copulation and egg-bearing femaleswere detected earlier by fish than individual non-ovigerousfemales or males, and pairs in copulation were captured mosteasily by fish. Cyclops vicinus mated less often when Chaoboruslarvae were present than in water in which Chaoborus was previouslyheld, or in pure tap water. However, predator presence or exposureto predator-treated water had no effect on (i.e. did not reduce)mating duration. Activity of C.vicinus pairs during copulationwas significantly lower when a predator was present, or in predator-treatedwater, than in pure tap water, and activity of pairs decreasedwith increasing activity of the predator. Although our experimentswere carried out under artificial conditions which cannot betransferred to the complex conditions in the field, they suggestthat mating in copepods is dangerous and that copepods haveevolved particular strategies to reduce the risk of predationduring mating.     

Is reduction of the benthivorous fish an important cause of high transparency following biomanipulation in shallow lakes?

Experimental reduction of the fish stock in two shallow lakes in The Netherlands shows that such a biomanipulation can lead to a substantial increase in transparency, which is caused not only by a decrease in algal biomass, but also by a decrease in resuspended sediment and detritus. A model was developed to describe transparency in relation to chlorophyll-a and inorganic, suspended solids (resuspended sediment). With the use of this model it is shown that more than 50% of the turbidity in these shallow lakes before biomanipulation was determined by the sediment resuspension, mainly caused by benthivorous fish. Another analysis reveals that the concentration of inorganic suspended solids and the biomass of benthivorous fish are positively correlated, and that even in the absence of algae a benthivorous fish biomass of 600 kg ha⁻¹ can reduce the Secchi depth to 0.4 m in shallow lakes. In addition, it is argued that algal biomass is also indirectly reduced by removal of benthivorous fish. Reduction of benthivorous fish is necessary to get macrophytes and macrophytes seem to be necessary to keep the algal biomass low in nutrient-rich shallow lakes. It is concluded that the impact of benthivorous fish on the turbidity can be large, especially in shallow lakes.     

Is the shift in chronotype associated with an alteration in well-being?

The study aimed to test whether a shift in chronotype (determined by mid-sleep on free days) is associated with alterations in psychological well-being and sleep parameters. One hundred and seventeen undergraduates were tested in longitudinal study with four repeated measures. Measurements were taken during spring in three-week intervals and each measurement consisted of self-reported sleep parameters on work and free days (i.e. bedtime, sleep latency, wake time, sleep onset, mid-sleep time, social jetlag), satisfaction with life, and mood (energetic arousal, tense arousal, hedonic tone). Between-subjects analyses revealed earlier chronotypes, as compared to the later ones, showing lower tense arousal, higher energetic arousal and life satisfaction, earlier bedtime, sleep onset and offset on both work and free days, longer sleep duration and shorter sleep latency on workdays, and less social jetlag. Within-subjects analyses revealed increasing photoperiod associated with a shift toward earlier chronotype, decrease in social jetlag, and shortening sleep latency. The seasonal shift toward earlier chronotype was not associated with alterations in mood or life satisfaction, but it was associated with a shift toward earlier bedtimes and longer sleep duration on workdays, decrease in sleep latency, and social jetlag. Results from the within-subjects analyses were consistent with the results of between-subjects analyses regarding sleep–wake functioning, but inconsistent regarding psychological outcomes.     

Is transformation associated with an increased error frequency in mammalian cells?

Acute starvation of mammalian cells for amino acids results in translational errors that may be detected by two-dimensional polyacrylamide gel electrophoresis. Using this as an assay for error frequency in mammalian cells, we investigated the hypothesis that neoplastic transformation was associated with an increased error frequency which in turn leads to an increased mutation rate and a decreased efficiency of regulatory controls (phenomena of tumor progression). Although we found that transformation was not always associated with an increased level of mistranslation we showed that SV40 transformation increased the level of translational errors in all cell types tested.     

Cannabis exposure associated with weight reduction and β-cell protection in an obese rat model

The aim of this study was to investigate the effect of an organic cannabis extract on β-cell secretory function in an in vivo diet-induced obese rat model and determine the associated molecular changes within pancreatic tissue. Diet-induced obese Wistar rats and rats fed on standard pellets were subcutaneously injected with an organic cannabis extract or the vehicle over a 28-day period. The effect of diet and treatment was evaluated using the intraperitoneal glucose tolerance tests (IPGTTs) and qPCR analysis on rat pancreata harvested upon termination of the experiment. The cafeteria diet induced an average weight difference of 32g and an overall increase in body weight in the experimental groups occurred at a significantly slower rate than the control groups, irrespective of diet. Area under the curve for glucose (AUC(g)) in the obese group was significantly lower compared to the lean group (p<0.001), with cannabis treatment significantly reducing the AUC(g) in the lean group (p<0.05), and remained unchanged in the obese group, relative to the obese control group. qPCR analysis showed that the cafeteria diet induced down-regulation of the following genes in the obese control group, relative to lean controls: UCP2, c-MYC and FLIP. Cannabis treatment in the obese group resulted in up-regulation of CB1, GLUT2, UCP2 and PKB, relative to the obese control group, while c-MYC levels were down-regulated, relative to the lean control group. Treatment did not significantly change gene expression in the lean group. These results suggest that the cannabis extract protects pancreatic islets against the negative effects of obesity.     

Is HIV infection associated with an increased risk for cholera? Insights from a mathematical model

Cholera, a waterborne gastroenteric infection, remains a significant threat to public health in sub-Saharan Africa, the region most heavily affected by HIV. It is biologically plausible that immune suppression caused by HIV infection predisposes to cholera. In this paper, a simple mathematical model is developed and comprehensively analyzed to assess whether HIV infection is associated with an increased risk for cholera or not. Analytical results of the model show that the quantities R(c) and R(h), which represents the reproductive number for cholera and HIV infection, respectively, provide threshold conditions that determine cumulative new single and dual infection cases. These threshold conditions can be used to gain important insights on the epidemiological consequences of HIV and cholera coexistence in the community. Numerical results are provided to support the analytical findings. The findings suggest that in a cholera-endemic area, HIV infection is associated with an increased risk for cholera.     

Is traditional contraceptive use in Moldova associated with poverty and isolation?

This study investigates the correlates of traditional contraceptive use in Moldova, a poor country in Europe with one of the highest proportions of traditional contraceptive method users. The high reliance on traditional methods, particularly in the context of sub-replacement level fertility rate, has not been systematically evaluated in demographic research. Using cross-sectional data on a sub-sample of 6039 sexually experienced women from the 2005 Moldovan Demographic and Health Survey, this study hypothesizes that (a) economic and spatial disadvantages increase the likelihood of traditional method use, and (b) high exposure to family planning/reproductive health (FP/RH) programmes increases the propensity to modern method use. Multilevel multinomial models are used to examine the correlates of traditional method use controlling for exposure to sexual activity, socioeconomic and demographic characteristics and data structure. The results show that economic disadvantage increases the probability of traditional method use, but the overall effect is small. Although higher family planning media exposure decreases the reliance on traditional methods among younger women, it has only a marginal effect in increasing modern method use among older women. Family planning programmes designed to encourage women to switch from traditional to modern methods have some success--although the effect is considerably reduced in regions outside of the capital Chisinau. The study concludes that FP/RH efforts directed towards the poorest may have limited impact, but interventions targeted at older women could reduce the burden of unwanted pregnancies and abortions. Addressing differentials in accessing modern methods could improve uptake in rural areas.     

Is genome downsizing associated with diversification in polyploid lineages of Veronica?

The study of genome size evolution in a phylogenetic context in related polyploid and diploid lineages can help us to understand the advantages and disadvantages of genome size changes and their effect on diversification. Here, we contribute 199 new DNA sequences and a nearly threefold increase in genome size estimates in polyploid and diploid Veronica (Plantaginaceae) (to 128 species, c. 30% of the genus) to provide a comprehensive baseline to explore the effect of genome size changes. We reconstructed internal transcribed spacer (ITS) and trnL‐trnL‐trnF phylogenetic trees and performed phylogenetic generalized least squares (PGLS), ancestral character state reconstruction, molecular dating and diversification analyses. Veronica 1C‐values range from 0.26 to 3.19 pg. Life history is significantly correlated with 1C‐value, whereas ploidy and chromosome number are strongly correlated with both 1C‐ and 1Cx‐values. The estimated ancestral Veronica 1Cx‐value is 0.65 pg, with significant genome downsizing in the polyploid Southern Hemisphere subgenus Pseudoveronica and two Northern Hemisphere subgenera, and significant genome upsizing in two diploid subgenera. These genomic downsizing events are accompanied by increased diversification rates, but a ‘core shift’ was only detected in the rate of subgenus Pseudoveronica. Polyploidy is important in the evolution of the genus, and a link between genome downsizing and polyploid diversification and species radiations is hypothesized. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 178 , 243–266.     

Is the concentration of C-reactive protein in bacteraemia associated with age?

Background  

C-reactive protein (CRP) is an indicator of inflammation, and is often used in the diagnosis of bacterial infections. It is poorly known whether CRP in bacterial infection is age-dependent.     

Is infection with Chlamydia pneumoniae a causative agent in atherosclerosis?

There is mounting evidence to suggest that Chlamydia pneumoniae might play a role in atherosclerosis. Serological studies and detection of the microorganism in atheromatous lesions were the first indications of an association between C. pneumoniae and the disease. Studies suggest that anti-chlamydial chemotherapy has a favorable effect on cardiovascular disease in humans. Moreover, infection of animals with C. pneumoniae induces inflammatory changes in the aorta that are suggestive of atherosclerosis and accelerates the progression of existing atherosclerotic lesions. If the pathogenic role of C. pneumoniae in atherosclerosis is defined more conclusively by future studies, the development of preventive or therapeutic measures against infection might provide an effective strategy to reduce the risk of atherosclerosis.     

Is low-frequency distribution of TGF-beta genotype associated with increased risk for end-stage renal disease?

End-stage renal disease has been associated with an inflammatory state. TGF-beta plays a critical role in antiinflammation counteracting inflammatory cytokines, wound healing, and tissue repair. We, therefore, speculated the protective role of TGF-beta in renal inflammation rather than inducing fibrosis. Three polymorphisms of TGF-beta (713-8delC), i.e., C deletion in intron sequence 8 base prior to exon-5 by PCR-RFLP and codon-10, Leu/Pro, and codon-25, Arg/Pro by Amplification Refractory Mutation System (ARMS-PCR) techniques were genotyped in 228 end-stage renal disease (ESRD) patients and 180 controls. Linkage disequilibrium (LD) and haplotype analysis was performed by Arlequin software. Our data showed positive association between codon-10 polymorphism and ESRD risk (P < 0.001; OR 4.845, 95% CI 2.57-9.11 for Pro/Pro). However, genotype frequencies were comparable in patients and controls for 713-8delC, while in the case of codon-25, a trend of higher frequency of Pro/Pro genotype (16.2% versus 10.0%) was observed but the P-value did not reach significant (P = 0.187). Significant association of codon-10 Pro/Pro was observed in patients with glomerulonephritis (P = 0.001; OR 4.138, 95%CI 2.1-8.13). LD was found significant between codon-10 and 25 (P = 0.021). Haplotype "Pro-Pro" showed 1.8-fold higher risk for ESRD (p = 0.003; OR = 1.867, 95%CI = 1.229-2.838). A combined analysis of the effect of TGF-beta (codon-10) with C-deletion and codon-25 showed significant difference for TGF-beta(10)-TGF-beta(C-del) (P = 0.010). In conclusion, the present study suggests that low-producing genotype (Pro/Pro) of TGF-beta (codon-10) polymorphism is associated with ESRD. Haplotype analysis further suggested that "Pro-Pro" (low producer) is associated with higher risk for ESRD. Thus, high-producing genotype of TGF-beta may be beneficial and may play a potential role in the resolution of renal inflammation.     

Is ceruloplasmin an important catalyst for S-nitrosothiol generation in hypercholesterolemia?

Nitric oxide (NO) reacts with thiol-containing biomolecules to form S-nitrosothiols (RSNOs). RSNOs are considered as NO reservoirs as they generate NO by homolytic cleavage. Ceruloplasmin has recently been suggested to have a potent catalytic activity towards RSNO production. Considering that NO activity is impaired in hypercholesterolemia and that RSNOs may act as important NO donors, we investigated the relation between concentrations of ceruloplasmin and RSNOs in plasma of hypercholesterolemic (HC) patients compared to normolipidemic (N) controls. Concentrations of ceruloplasmin (0.36 +/- 0.07 x 0.49 +/- 0.11 mg/dl, N x HC), nitrate (19.10 +/- 12.03 x 40.19 +/- 18.70 microM, N x HC), RSNOs (0.25 +/- 0.20 x 0.54 +/- 0.26 microM, N x HC), nitrated LDL (19.51 +/- 6.98 x 35.29 +/- 17.57 nM nitro-BSA equivalents, N x HC), and cholesteryl ester-derived hydroxy/hydroperoxides (CEOOH, 0.19 +/- 0.06 x 1.46 +/- 0.97 microM) were increased in plasma of HC as compared to N. No difference was found for nitrite levels between the two groups (1.01 +/- 0.53 x 1.02 +/- 0.33 microM, N x HC). The concentrations of RSNOs, nitrate, and nitrated LDL were positively correlated to those of total cholesterol, LDL cholesterol, and apoB. Ceruloplasmin levels were directly correlated to apoB and apoE concentrations. Data suggest that: (i) ceruloplasmin may have a role in the enhancement of RSNOs found in hypercholesterolemia; (ii) the lower NO bioactivity associated with hypercholesterolemia is not related to a RSNOs paucity or a defective NO release from RSNOs; and (iii) the increased nitrotyrosine levels found in hypercholesterolemia indicate that superoxide radicals contribute to inactivation of NO, directly generated by NO synthase or originated by RSNO decomposition.     

Is there evidence for an age-related reduction in metabolic rate?

To determinewhether the age-related reduction in basal metabolic rate (BMR) isexplained by a quantitative and/or qualitative change in thecomponents of lean tissue, we conducted a cross-sectional study ingroups of young (n = 38, 18-35yr) and older (n = 24, 50-77 yr)healthy individuals. BMR was measured by indirect calorimetry. Bodycomposition was obtained by using dual-energy X-ray absorptiometry (DEXA), which permitted four compartments to be quantified [bone mineral mass, fat mass (FM), appendicular lean tissue mass(A_LTM), and nonappendicular leantissue mass (NA_LTM)].Absolute BMR and A_LTM were lower,whereas FM was significantly higher in the older, compared with young,subjects. BMR, adjusted for differences in FM,A_LTM, andNA_LTM, was significantly lower inthe older subjects by 644 kJ/day. In separate regression analyses ofBMR on body compartments, older subjects had significantly lowerregression coefficients for A_LTMand NA_LTM, compared with youngsubjects. Hence, the age-related decline in BMR is partly explained bya reduction in the quantity, as well as the metabolic activity, ofDEXA-derived lean tissue components.

     

Perinatal and early life risk factors for childhood brain tumors: Is instrument-assisted delivery associated with higher risk?

BackgroundThe childhood peak of brain tumors suggests that early-life exposures might have a role in their etiology. Hence, we examined in the Greek National Registry for Childhood Hematological Malignancies and Solid tumors (NARECHEM-ST) whether perinatal and early-life risk factors influence the risk of childhood brain tumors.MethodsIn a nationwide case-control study, we included 203 cases (0–14 years) with a diagnosis of brain tumor in NARECHEM-ST (2010–2016) and 406 age-, sex-, and center-matched hospital controls. Information was collected via interviews with the guardians and we analyzed the variables of interest in multivariable conditional logistic regression models.ResultsInstrument-assisted delivery was associated with higher (OR: 7.82, 95%CI: 2.18–28.03), whereas caesarean delivery with lower (OR: 0.67, 95%CI: 0.45-0.99) risk of childhood brain tumors, as compared to spontaneous vaginal delivery. Maternal alcohol consumption during pregnancy (OR: 2.35, 95%CI: 1.45–3.81) and history of living in a farm (OR: 4.98, 2.40–10.32) increased the odds of childhood brain tumors. Conversely, higher birth order was associated with lower risk (OR for 2nd vs. 1st child: 0.60, 95%CI: 0.40-0.89 and OR for 3^rd vs. 1^st: 0.34, 95%CI: 0.18-0.63). Birth weight, gestational age, parental age, history of infertility, smoking during pregnancy, allergic diseases, and maternal diseases during pregnancy showed no significant associations.ConclusionsPerinatal and early-life risk factors, and specifically indicators of brain trauma, exposure to toxic agents and immune system maturation, might be involved in the pathogenesis of childhood brain tumors. Larger studies should aim to replicate our findings and examine associations with tumor subtypes.     

Is regulation of proteolysis associated with redox-state changes in rat skeletal muscle?

In isolated rat diaphragms, only those substrates that increased the tissue NADH/NAD+ ratio lowered the rate of proteolysis. However, direct inhibition of proteinase activity by leupeptin promoted oxidation of the NAD couple of the muscles. These results suggest that changes in muscle reduction-oxidation state may be important in the regulation of proteolysis.     

Is circadian type associated with sleep duration in twins?

Sleep and Biological Rhythms - We used the community-based University of Washington Twin Registry to investigate the genetic association between circadian type and sleep duration. Habitual sleep...     

Is early osteoarthritis associated with differences in joint congruence?

Previous studies suggest that osteoarthritis (OA) is related to abnormal or excessive articular contact stress. The peak pressure resulting from an applied load is determined by many factors, among which is shape and relative position and orientation of the articulating surfaces or, referring to a more common nomenclature, joint congruence. It has been hypothesized that anatomical differences may be among the causes of OA. Individuals with less congruent joints would likely develop higher peak pressure and thus would be more exposed to the risk of OA onset. The aim of this work was to determine if the congruence of the first carpometacarpal (CMC) joint differs with the early onset of OA or with sex, as the female population has a higher incidence of OA. 59 without and 38 with early OA were CT-scanned with their dominant or arthritic hand in a neutral configuration. The proposed measure of joint congruence is both shape and size dependent. The correlation of joint congruence with pathology and sex was analyzed both before and after normalization for joint size. We found a significant correlation between joint congruence and sex due to the sex-related differences in size. The observed correlation disappeared after normalization. Although joint congruence increased with size, it did not correlate significantly with the onset of early OA. Differences in joint congruence in this population may not be a primary cause of OA onset or predisposition, at least for the CMC joint.