• Gestational stress induces post-partum depression-like behaviour and alters maternal care in rats

      Smith, Jeremy W.; Seckl, J.R.; Evans, A. Tudor; Costall, Brenda; Smythe, James W. (2004)
      Gestational stress (GS) produces profound behavioural impairments in the offspring and may permanently programme hypothalamic¿pituitary¿adrenal (HPA) axis function. We investigated whether or not GS produced changes in the maternal behaviour of rat dams, and measured depression-like behaviour in the dam, which might contribute to effects in the progeny. We used the Porsolt test, which measures immobility in a forced-swim task, and models depression in rodents, while monitoring maternal care (arched-back nursing, licking/grooming, nesting/grouping pups). Pregnant rats underwent daily restraint stress (1 h/day, days 10¿20 of gestation), or were left undisturbed (control). On post-parturition days 3 and 4, dams were placed into a swim tank, and time spent immobile was measured. GS significantly elevated immobility scores by approximately 25% above control values on the second test day. Maternal behaviours, in particular arched-back nursing and nesting/grouping pups, were reduced in GS dams over post-natal days 1¿10. Adult offspring showed increased immobility in the Porsolt test, and also hypersecreted ACTH and CORT in response to an acute stress challenge. These data show that GS can alter maternal behaviour in mothers, and this might contribute to alterations in the offspring. GS may be an important factor in maternal post-natal depression, which may in turn detrimentally effect the offspring because depressed mothers do not sufficiently care for their offspring.
    • Influence of positive and negative dimensions of dementia caregiving on caregiver well-being and satisfaction with life: Findings from the IDEAL study

      Quinn, Catherine; Nelis, S.M.; Martyr, A.; Victor, C.; Morris, R.G. (2019-08)
      The aim of this study was to identify the potential impact of positive and negative dimensions of caregiving on caregiver well-being and satisfaction with life (SwL). This study used time-point one data from the Improving the experience of Dementia and Enhancing Active Life (also known as IDEAL)cohort study that involved 1,283 informal caregivers of people in the mild-to-moderate stages of dementia recruited from 29 sites within Great Britain. Multivariate linear regression modeling was used to investigate the associations between positive dimensions of caregiving (measured by caregiving competence and perceptions of positive aspects of caregiving), negative dimensions of caregiving (measured by caregiving stress and role captivity), and caregiver well-being and SwL. Lower well-being was associated with low caregiving competence (–13.77; 95% confidence interval [CI]:–16.67, –10.87), perceiving fewer positive aspects of caregiving (–7.67; 95% CI:–10.26, –5.07), high caregiving stress (–24.45; 95% CI:–26.94, –21.96), and high role captivity (–15.61; 95% CI:–18.33, –12.89). Lower SwL was associated with low caregiving competence (–4.61; 95% CI:–5.57, –3.66), perceiving fewer positive aspects of caregiving (–3.09; 95% CI:–3.94, –2.25), high caregiving stress (–7.88; 95% CI:–8.71, –7.06), and high role captivity (–6.41; 95% CI:–7.27, –5.54). When these four measures were combined within the same model, only positive aspects of caregiving and caregiving stress retained independent associations with well-being and SwL. Both positive and negative dimensions of caregiving were associated with caregiver well-being and SwL. Psychological therapies and interventions need to consider not only the negative aspects of caregiving but also positive caregiving experiences and their implications for caregiver well-being and SwL.
    • Nucleosides Rescue Replication-Mediated Genome Instability of Human Pluripotent Stem Cells

      Ivana, Barbaric,; Peter W, Andrews,; Halliwell, J.A.; Frith, T.J.R.; Laing, O.; Price, C.J.; Bower, O.J.; Stavish, T.; Gokhale, P.J.; Hewitt, Z.; et al. (2020-06-09)
      Human pluripotent stem cells (PSCs) are subject to the appearance of recurrent genetic variants on prolonged culture. We have now found that, compared with isogenic differentiated cells, PSCs exhibit evidence of considerably more DNA damage during the S phase of the cell cycle, apparently as a consequence of DNA replication stress marked by slower progression of DNA replication, activation of latent origins of replication, and collapse of replication forks. As in many cancers, which, like PSCs, exhibit a shortened G1 phase and DNA replication stress, the resulting DNA damage may underlie the higher incidence of abnormal and abortive mitoses in PSCs, resulting in chromosomal non-dysjunction or cell death. However, we have found that the extent of DNA replication stress, DNA damage, and consequent aberrant mitoses can be substantially reduced by culturing PSCs in the presence of exogenous nucleosides, resulting in improved survival, clonogenicity, and population growth.
    • Perturbed 6-tetrahydrobiopterin recycling via decreased dihydropteridine reductase in vitiligo: More evidence for H2O2 stress.

      Hasse, Sybille; Gibbons, Nick C.; Rokos, Hartmut; Marles, Lee K.; Schallreuter, Karin U. (2004)
      To date there is ample evidence that patients with vitiligo accumulate millimolar concentrations of hydrogen peroxide (H2O2) in their epidermis as well as in their blood lymphocytes/monocytes. Several enzymes are affected by this H2O2 including catalase, glutathione peroxidase, and 4¿-carbinolamine dehydratase. The latter enzyme disrupts the recycling of the essential cofactor (6R)-L-erythro-5,6,7,8-tetrahydrobiopterin (6BH4) for the aromatic amino acid hydroxylases as well as the nitric oxide synthases. In this report we have elucidated the influence of H2O2 on dihydropteridine reductase (DHPR), the last enzyme in the 6BH4-recycling process. Here we show for the first time that concentrations of less than 30 ¿M H2O2 increase DHPR activities, whereas levels greater than 30 ¿M H2O2 deactivate the enzyme based on the oxidation of Met146 and Met151 in the sequence, consequently leading to disruption of the NADH-dependent enzyme active site. This oxidation was confirmed by Fourier transform-Raman spectroscopy yielding the expected SO band at 1025 cm characteristic of methionine sulfoxide. Hence these results unmasked a novel regulatory mechanism for DHPR enzyme activity. Moreover, we also demonstrated that DHPR activities in whole blood of patients with vitiligo are significantly decreased in untreated patients, whereas activities are normalized after removal of epidermal H2O2 with a topical pseudocatalase (PC-KUS). Taken together, these new data add more evidence to a systemic involvement of H2O2 in the pathomechanism of vitiligo.
    • The whole tooth and nothing but the tooth: or why temporal resolution of bone collagen may be unreliable

      Beaumont, Julia (Wiley, 2020-06)
      The carbon (δ13C) and nitrogen (δ15N) isotope ratios of human bone collagen have been used extensively over the last 40 years to investigate the diet of past populations. It has become apparent that bone collagen can give an unreliable temporal dietary signature especially in juveniles. With higher temporal resolution sampling of collagen from tooth dentine, it is possible to identify short‐term changes in diet previously invisible in bone. This paper discusses the inherent problems of using bone collagen for dietary studies and suggests better sample choices which can make our interpretations more robust, using breastfeeding and weaning as an example.