Demonstration Of Such Effects Research Articles

Are There Epigenetic Oxytocin-Mediated Effects on the Mother and Infant during Physiological Childbirth?

Introduction: Studies have shown that long-term positive behavioural and physiological changes are induced in connection with vaginal, physiological birth, and skin-to-skin contact after birth in mothers and babies. Some of these effects are consistent with the effect profile of oxytocin. This scoping review explores whether epigenetic changes of the oxytocin gene and of the oxytocin receptor gene (OTR) are involved in these effects. Methods: We searched Pubmed, Medline, BioMed Central, Cochrane Library, OVID, and Web of Science for evidence of epigenetic changes in connection with childbirth in humans, with a particular focus on the oxytocin system. Results: There were no published studies identified that were related to epigenetic changes of oxytocin and its receptor in connection with labour, birth, and skin-to-skin contact after birth in mothers and babies. However, some studies were identified that showed polymorphisms of the oxytocin receptor influenced the progress of labour. We also identified studies in which the level of global methylation was measured in vaginal birth and caesarean section, with conflicting results. Some studies identified differences in the level of methylation of single genes linked to various effects, for example, immune response, metabolism, and inflammation. In some of these cases, the level of methylation was associated with the duration of labour or mode of birth. We also identified some studies that demonstrated long-term effects of mode of birth and of skin-to-skin contact linked to changes in oxytocin function. Conclusion: There were no studies identified that showed epigenetic changes of the oxytocin system in connection with physiological birth. The lack of evidence, so far, regarding epigenetic changes did not exclude future demonstrations of such effects, as there was a definite role of oxytocin in creating long-term effects during the perinatal period. Such studies may not have been performed. Alternatively, the oxytocin linked effects might be indirectly mediated via other receptors and signalling systems. We conclude that there is a significant lack of research examining long-term changes of oxytocin function and long-term oxytocin mediated adaptive effects induced during physiological birth and skin-to-skin contact after birth in mothers and their infants.

Can confidence help account for and redress the effects of reading inaccurate information?

Being exposed to inaccurate information in fiction can negatively influence post-reading judgments and decisions. For example, people make more errors judging the validity of statements after reading stories containing related inaccurate as compared to related accurate assertions. While these effects have been demonstrated in a variety of studies, people's confidence in their post-reading judgments has received little attention. The current experiments examined whether exposure to accurate and inaccurate information embedded in fiction influences readers' confidence in judging the validity of related claims. Participants read an extended story containing accurate and inaccurate assertions about the world (Experiment 1a) or a control story omitting those assertions (Experiment 1b). Afterwards they judged the validity of single statements related to the critical assertions and provided confidence ratings for each judgment. While participants made more judgment errors after having read inaccurate assertions than after having read accurate assertions or stories without assertions, they were overall less confident in their incorrect as compared to correct judgments. Given the observed relationship between confidence and judgment accuracy, in Experiments 2 and 3 we tested whether allowing and instructing participants to withhold responses might reduce judgment errors. This withholding option reduced participants' incorrect and correct judgments, failing to specifically eliminate the negative consequences of exposure to inaccurate assertions. These findings are discussed with respect to accounts documenting the influence of inaccurate information, and highlight confidence as a relevant but understudied factor in previous empirical demonstrations of such effects.

Community trait overdispersion due to trophic interactions: concerns for assembly process inference.

The expected link between competitive exclusion and community trait overdispersion has been used to infer competition in local communities, and trait clustering has been interpreted as habitat filtering. Such community assembly process inference has received criticism for ignoring trophic interactions, as competition and trophic interactions might create similar trait patterns. While other theoretical studies have generally demonstrated the importance of predation for coexistence, ours provides the first quantitative demonstration of such effects on assembly process inference, using a trait-based ecological model to simulate the assembly of a competitive primary consumer community with and without the influence of trophic interactions. We quantified and contrasted trait dispersion/clustering of the competitive communities with the absence and presence of secondary consumers. Trophic interactions most often decreased trait clustering (i.e. increased dispersion) in the competitive communities due to evenly distributed invasions of secondary consumers and subsequent competitor extinctions over trait space. Furthermore, effects of trophic interactions were somewhat dependent on model parameters and clustering metric. These effects create considerable problems for process inference from trait distributions; one potential solution is to use more process-based and inclusive models in inference.

The effect of eye movements and blinks on afterimage appearance and duration.

The question of whether eye movements influence afterimage perception has been asked since the 18th century, and yet there is surprisingly little consensus on how robust these effects are and why they occur. The number of historical theories aiming to explain the effects are more numerous than clear experimental demonstrations of such effects. We provide a clearer characterization of when eye movements and blinks do or do not affect afterimages with the aim to distinguish between historical theories and integrate them with a modern understanding of perception. We found neither saccades nor pursuit reduced strong afterimage duration, and blinks actually increased afterimage duration when tested in the light. However, for weak afterimages, we found saccades reduced duration, and blinks and pursuit eye movements did not. One interpretation of these results is that saccades diminish afterimage perception because they cause the afterimage to move unlike a real object. Furthermore, because saccades affect weak afterimages but not strong ones, we suggest that their effect is modulated by the ambiguity of the afterimage signal.

Artificial Neural Network classification of operator workload with an assessment of time variation and noise-enhancement to increase performance.

Workload classification—the determination of whether a human operator is in a high or low workload state to allow their working environment to be optimized—is an emerging application of passive Brain-Computer Interface (BCI) systems. Practical systems must not only accurately detect the current workload state, but also have good temporal performance: requiring little time to set up and train the classifier, and ensuring that the reported performance level is consistent and predictable over time. This paper investigates the temporal performance of an Artificial Neural Network based classification system. For networks trained on little EEG data good classification accuracies (86%) are achieved over very short time frames, but substantial decreases in accuracy are found as the time gap between the network training and the actual use is increased. Noise-enhanced processing, where artificially generated noise is deliberately added to the testing signals, is investigated as a potential technique to mitigate this degradation without requiring the network to be re-trained using more data. Small stochastic resonance effects are demonstrated whereby the classification process gets better in the presence of more noise. The effect is small and does not eliminate the need for re-training, but it is consistent, and this is the first demonstration of such effects for non-evoked/free-running EEG signals suitable for passive BCI.

The effect of mobile phone electromagnetic fields on the alpha rhythm of human electroencephalogram

Mobile phones (MP) emit low-level electromagnetic fields that have been reported to affect neural function in humans; however, demonstrations of such effects have not been conclusive. The purpose of the present study was to test one of the strongest findings in the literature; that of increased "alpha" power in response to MP-type radiation. Healthy participants (N = 120) were tested using a double-blind counterbalanced crossover design, with each receiving a 30-min Active and a 30-min Sham Exposure 1 week apart, while electroencephalogram (EEG) data were recorded. Resting alpha power (8-12 Hz) was then derived as a function of time, for periods both during and following exposure. Non-parametric analyses were employed as data could not be normalized. Previous reports of an overall alpha power enhancement during the MP exposure were confirmed (relative to Sham), with this effect larger at ipsilateral than contralateral sites over posterior regions. No overall change to alpha power was observed following exposure cessation; however, there was less alpha power contralateral to the exposure source during this period (relative to ipsilateral). Employing a strong methodology, the current findings support previous research that has reported an effect of MP exposure on EEG alpha power.

Effects of Concurrent Therapy with Policosanol and Omega-3 Fatty Acids on Lipid Profile and Platelet Aggregation in Rabbits

Policosanol is a mixture of high-molecular-weight aliphatic primary alcohols isolated from sugarcane wax with cholesterol-lowering and antiplatelet effects. Omega-3 fatty acids (FA) from fish oil can protect against coronary disease. An antiarrhythmic mechanism is emerging as the most convincing explanation for omega-3 FA cardiovascular protection, but triglyceride (TG)-lowering effects and inhibition of platelet function could play a role. In view of the effects of policosanol and omega-3 FA on lipid profile and platelet function, potential benefits of combined therapy were expected. To investigate whether combined therapy with policosanol and omega-3 FA would offer some benefit, compared with policosanol or omega-3 FA alone, on serum lipid profile and platelet aggregation in rabbits. Male rabbits were randomly distributed in four groups (n = 9 per group). A control group received vehicle, one group was treated with policosanol 5 mg/kg and one with omega-3 FA (eicosapentaenoic acid; EPA [47.0%], docosahexaenoic acid; DHEA [41%]) 250 mg/kg, and the fourth received policosanol 5 mg/kg + omega-3 FA 250 mg/kg. Treatments were orally administered for 60 days. Bodyweight, food consumption and animal behaviour were performed at baseline and study completion. Policosanol significantly lowered low-density lipoprotein cholesterol (LDL-C) [42.7%; p < 0.01] and total cholesterol (TC) [29.4%; p < 0.05], increased high-density lipoprotein (HDL-C) [15.4%; p < 0.05], but left TG levels unchanged. Omega-3 FA significantly lowered TG (47.1%; p < 0.05), but left TC, LDL-C and HDL-C unchanged. Combined therapy decreased LDL-C (38.7%; p < 0.05). Changes in TC, LDL-C and HDL-C obtained with combined therapy were greater (p < 0.05) than those with omega-3 FA, but similar to those with policosanol, whereas the opposite applied to TG reduction. No significant changes in lipid profile were observed in the control group. Policosanol and omega-3 FA significantly (p < 0.05) but moderately inhibited platelet aggregation induced with arachidonic acid (13.3% and 12.4%, respectively); combined therapy achieved greater inhibition (23.9%; p < 0.05). All groups showed similar food consumption and bodyweight gain. No toxic signs were observed in any animal. Concurrent therapy with policosanol 5 m/kg and omega-3 FA 250 mg/kg lowered LDL-C, TC and TG and increased HDL-C. All treatments inhibited platelet aggregation, but better effects were observed with policosanol + omega-3 FA compared with either treatment alone. Combined therapy was well tolerated. These results suggest that treatment with policosanol + omega-3 FA could be useful for regulating lipid profile and inhibiting platelet aggregation, but conclusive demonstration of such effects requires further experimental and clinical studies.

Observation of Pr and Gd ordering in the 2212-type compounds (Pb0.5Cu0.5)2(Ba0.5Sr0.5)2RCu2O8 (R=Pr,Gd).

Magnetic and calorimetric measurements have been made to reveal a Pr ordering in the (${\mathrm{Pb}}_{0.5}$${\mathrm{Cu}}_{0.5}$${)}_{2}$(${\mathrm{Ba}}_{0.5}$${\mathrm{Sr}}_{0.5}$${)}_{2}$${\mathrm{PrCu}}_{2}$${\mathrm{O}}_{8}$ compound which has the (Pb,Cu)-2212-type tetragonal structure with lattice parameters a=3.878(3) \AA{} and c=27.594(9) \AA{}. The transition occurs at a relatively high ${\mathit{T}}_{\mathit{N}}$(Pr) of 9 K. In comparison, isostructural (${\mathrm{Pb}}_{0.5}$${\mathrm{Cu}}_{0.5}$${)}_{2}$(${\mathrm{Ba}}_{0.5}$${\mathrm{Sr}}_{0.5}$${)}_{2}$${\mathrm{GdCu}}_{2}$${\mathrm{O}}_{8}$ exhibits a ${\mathit{T}}_{\mathit{N}}$(Gd) of only 2.2 K. The magnetic entropy associated with the Pr ordering has a lower limit value equivalent to about 20% of Rln3 expected for ${\mathrm{Pr}}^{3+}$ with a quasitriplet ground state, suggesting a more three-dimensional-like process. These results represent the observation of anomalous Pr ordering in the 2212-type cuprate and a complete demonstration of such effects in all two-${\mathrm{CuO}}_{2}$-layer m212 (m=1,2,3) systems.

L-3,4-dihydroxyphenylalanine (levodopa) lowers central nervous system S-adenosylmethionine concentrations in humans.

To determine whether levodopa reduces the levels of S-adenosylmethionine in the human central nervous system, cerebrospinal fluid (CSF) concentrations of S-adenosylmethionine, methionine, 3-methoxytyrosine, levodopa and 5-methyltetrahydrofolate were measured in six children with dopamine deficiency before and after treatment. In four, the lack of dopamine was secondary to a reduction in concentration of levodopa and these were treated with levodopa together with a peripheral dopa-decarboxylase inhibitor. In the other two, levodopa in the central nervous system naturally accumulated due to a congenital deficiency of aromatic-L-amino acid decarboxylase and these were treated with pyridoxine (which in this condition lowers central levodopa concentrations). Raising levodopa concentrations in the central nervous system caused a fall in CSF S-adenosyl-methionine concentration and a rise in CSF 3-methoxytyrosine concentration. No change was observed in CSF methionine concentration and in all patients CSF 5-methyltetrahydrofolate concentration was normal. With one exclusion there was a linear relationship between CSF S-adenosylmethionine and 3-methoxytyrosine concentrations. This is the first demonstration of such effects in humans and the implications upon levodopa therapy are discussed.

Ganglioside GM1 overcomes serum inhibition of neuritic outgrowth

Considerable variations in both neuritic and non-neuronal cell outgrowths of ganglionic expiant cultures are imposed when different substrata and medium supplements are used. Therefore, a neuritic response to exogenous agents such as gangliosides may be better, or exclusively revealed under selected combinations of medium and substratum. We have surveyed a number of different ganglia for their ability to display a neuritic response to ganglioside GM1 and the culture conditions under which such a display may take place. GM1 can recognizably promote neurite extension from embryonic day 8 chick dorsal root ganglia, day 11 sympathetic ganglia, and day 8 ciliary ganglia. Demonstration of such effects, however, requires an appropriate balance between promoting and inhibiting influences by other extrinsic influences (culture substrata, neuronotrophic factors, serum inhibitors) thereby allowing for improvement by the ganglioside. Different ganglia require different combinations of those influences. Ciliary ganglia, for example, will show a GM1 response on a polyornithine substratum in medium supplemented with the chick eye Ciliary Neuronotrophic Factor and 1% fetal calf serum, but not with 10% serum or no serum. The effective concentration range for GM1 is in accord with previously reported serum binding data. These, and other data are consistent with an action of GM1 in executing a neurite program, rather than an imposition of the program itself.

Causes of death in irradiated adult insects.

Summary1. Irradiation of adult insects of many orders leads to their death. There is considerable evidence that such death occurs during a limited time period, both the beginning and duration of which are relatively independent of the dose over a wide range. This suggests the operation of a specific lethal syndrome. In other groups of insects, particularly Diptera and many moths, either the absence of somatic‐cell division or the short life of the imago prevents the development of this syndrome. These latter groups require much higher doses of radiation for the induction of demonstrable mortality, and the time‐course of mortality is closely related to the size of the dose.2. Superficially, at least, radiation death of adult Diptera is comparable to that of supralethally irradiated insects of the taxa which exhibit the specific lethal syndrome after lower doses. There are some observations suggesting that the nervous system becomes involved after these high doses, just as there are for mammals exposed to high doses.3. There is also some evidence, very convincing in itself, although available only from a small number of experiments, that the specific syndrome observed after lower lethal or mid‐lethal doses is a consequence of damage to the midgut, particularly to its regenerative cells. This clearly is analogous to the intestinal syndrome of mammals; as in the mammal, the processes which intervene between the cellular damage and the death of the organism remain in the realm of conjecture or controversy. This appears to be one of several areas in which more detailed investigation of the radiobiological phenomenon is certain to provide valuable information on normal physiological activities.4. The response of insects differs greatly from that of mammals in that effects on disease‐resistance mechanisms, both cellular and humoral, are not prominent. The dose required for unequivocal demonstration of such effects may be greater than the dose required to produce lethality. If endogenous infection contributes to lethality after irradiation of otherwise healthy insects, there is, as yet, no convincing evidence for it. Nevertheless, radiation may provide a useful tool for probing the mechanisms of disease resistance of insects, and for examining the regulation and the kinetics of haemocyte formation. In addition, irradiated insects might be used to select virulent strains of potential insect pathogens.5. Quantitative information on the response of insect cells, either in situ or in zlitro, is virtually non‐existent. Insect eggs have been used in a few investigations of cellular phenomena in radiation biology, but the only data applicable to dose‐response relationships are those of Murakami (1969, 1970), who has taken advantage of the synchronous division that occurs during the early embryonic development of Bombyx mori. The usefulness of insect cell‐cultures in delineating growth requirements and in propagating viruses has attracted far more attention than their potential for radiobiological investigations and other studies of cellular responses. This is not unlike the situation in the field of vertebrate cell‐culture prior to the mid‐1950s; the present time seems appropriate for developing insect cell‐culture into a tool for the radiation biologist.6. Apparently beneficial effects of radiation can be very spectacular in insects, but are not limited to insects, or, indeed, to invertebrates. The frequent demonstration of such effects in insects may stem, in part, from the greater resistance of insects than of vertebrates to the lethal effects of radiation. It must be remembered, however, that extension of the life‐span is found in insects surviving mid‐lethal doses of radiation. Alternatively, the lesser dependence of insects on cell‐renewal systems may permit the manifestation of a phenomenon that is common to many post‐mitotic tissues. If so, the causes of the extension of the insect life‐span after irradiation should also be of major interest to investigators of mammalian radiation biology and indeed to all gerontologists.I am grateful to Dr Judith H. Willis and Dr Benita S. Katzenellenbogen for reading the manuscript and for making a number of helpful suggestions. My own research on radiation responses of insects was supported by U.S. Public Health Service grants GM 10208 and HD 03163. Many of my concepts of the relationship between the responses of mammals and those of insects were formulated during tenure of a Public Health Service Special Fellowship, GM 23423, at the Department of Zoology, University of Cambridge; I am grateful to the members of that Department, and particularly to Dr J. W. L. Beament and to the late Professor C. F. A. Pantin, for their generosity and hospitality in making the resources of the Department available during my stay. I am especially indebted to Dr George Salt, for his patience and wisdom, and for personal kindnesses far too numerous to record.