624 research outputs found

    X-Ray Fluorescence Microscopy Reveals Accumulation and Secretion of Discrete Intracellular Zinc Pools in the Lactating Mouse Mammary Gland

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    The mammary gland is responsible for the transfer of a tremendous amount of zinc ( approximately 1-3 mg zinc/day) from maternal circulation into milk during lactation to support the growth and development of the offspring. When this process is compromised, severe zinc deficiency compromises neuronal development and immune function and increases infant morbidity and/or mortality. It remains unclear as to how the lactating mammary gland dynamically integrates zinc import from maternal circulation with the enormous amount of zinc that is secreted into milk.Herein we utilized X-ray fluorescence microscopy (XFM) which allowed for the visualization and quantification of the process of zinc transfer through the mammary gland of the lactating mouse. Our data illustrate that a large amount of zinc first accumulates in the mammary gland during lactation. Interestingly, this zinc is not cytosolic, but accumulated in large, discrete sub-cellular compartments. These zinc pools were then redistributed to small intracellular vesicles destined for secretion in a prolactin-responsive manner. Confocal microscopy identified mitochondria and the Golgi apparatus as the sub-cellular compartments which accumulate zinc; however, zinc pools in the Golgi apparatus, but not mitochondria are redistributed to vesicles destined for secretion during lactation.Our data directly implicate the Golgi apparatus in providing a large, mobilizable zinc storage pool to assist in providing for the tremendous amount of zinc that is secreted into milk. Interestingly, our study also provides compelling evidence that mitochondrial zinc pools expand in the mammary gland during lactation which we speculate may play a role in regulating mammary gland function

    Epigenetics as a mechanism driving polygenic clinical drug resistance

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    Aberrant methylation of CpG islands located at or near gene promoters is associated with inactivation of gene expression during tumour development. It is increasingly recognised that such epimutations may occur at a much higher frequency than gene mutation and therefore have a greater impact on selection of subpopulations of cells during tumour progression or acquisition of resistance to anticancer drugs. Although laboratory-based models of acquired resistance to anticancer agents tend to focus on specific genes or biochemical pathways, such 'one gene : one outcome' models may be an oversimplification of acquired resistance to treatment of cancer patients. Instead, clinical drug resistance may be due to changes in expression of a large number of genes that have a cumulative impact on chemosensitivity. Aberrant CpG island methylation of multiple genes occurring in a nonrandom manner during tumour development and during the acquisition of drug resistance provides a mechanism whereby expression of multiple genes could be affected simultaneously resulting in polygenic clinical drug resistance. If simultaneous epigenetic regulation of multiple genes is indeed a major driving force behind acquired resistance of patients' tumour to anticancer agents, this has important implications for biomarker studies of clinical outcome following chemotherapy and for clinical approaches designed to circumvent or modulate drug resistance

    Children’s experiences following a CBT intervention to reduce dental anxiety: one year on

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    Objective: To investigate children’s ongoing experiences of dental care and use of strategies to manage their dental anxiety following cognitive behavioural therapy (CBT). Design: A child self-completed postal questionnaire. Settings: Hospital, community and general dental practice. Subjects: Questionnaires were sent to 44 children, aged 10-17 years who had been referred to specialist services due to their dental anxiety. Intervention: Children had all previously received a guided CBT self-help intervention to reduce their dental anxiety and, on completion of treatment, had been discharged to their referring dentist. Questionnaires were sent out 12-18 months later to ascertain dental attendance patterns and application of any strategies learnt from the previous CBT intervention. Results: 22 responses (50%) were received from 16 girls and 6 boys. 82% had subsequently accessed follow up care with a general dental practitioner and over half of these had undergone a dental procedure, other than a check-up. 91% reported feeling less worried about dental visits, than previously, and described a change in cognition, behaviours, and feelings that allowed them to manage their anxiety better. Conclusions: CBT has positive immediate and longitudinal effects in reducing children’s dental anxiety. The challenge of adopting this evidence-based approach within primary care settings remains

    Immunobiological effects of gemcitabine and capecitabine combination chemotherapy in advanced pancreatic ductal adenocarcinoma

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    Background: Preclinical studies suggest that chemotherapy may enhance the immune response against pancreatic cancer. Methods: The levels of granulocyte macrophage-colony-stimulating factor (GM-CSF) and interleukin-6 (IL-6) and the associated inflammatory marker C-reactive protein (CRP) were assessed in 38 patients receiving gemcitabine and capecitabine combination chemotherapy for advanced pancreatic cancer within the TeloVac trial. Apoptosis (M30) and total immune response (delayed-type hypersensitivity and/or T-cell response) were also assessed and levels of apoptosis induction correlated with immune response. The telomerase GV1001 vaccine was given either sequentially (n=18) or concomitantly (n=24) with the combination chemotherapy. Results: There were no differences between baseline and post-treatment levels of CRP (P=0.19), IL-6 (P=0.19) and GM-CSF (P=0.71). There was a positive correlation between post-chemotherapy CRP and IL-6 levels (r=0.45, P=0.005) and between CRP with carbohydrate antigen-19-9 (CA19-9) levels at baseline (r=0.45, P=0.015) and post treatment (r=0.40, P=0.015). The change in CRP and IL-6 levels was positively correlated (r=0.40, P=0.012). Hazard ratios (95% CI) for baseline CA19-9 (1.30 (1.07–1.59), P=0.009) and CRP (1.55 (1.00–2.39), P=0.049) levels were each independently predictive of survival. The M30 mean matched differences between pre- and post-chemotherapy showed evidence of apoptosis in both the sequential (P=0.058) and concurrent (P=0.0018) chemoimmunotherapy arms. Respectively, 5 of 10 and 9 of 20 patients had a positive immune response but there was no association with apoptosis. Conclusions: Combination gemcitabine and capecitabine chemotherapy did not affect circulating levels of GM-CSF, IL-6 and CRP. Chemotherapy-induced apoptosis was not associated with the immunogenicity induced by the GV1001 vaccine in advanced pancreatic cancer

    CD200 Receptor Controls Sex-Specific TLR7 Responses to Viral Infection

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    Immunological checkpoints, such as the inhibitory CD200 receptor (CD200R), play a dual role in balancing the immune system during microbial infection. On the one hand these inhibitory signals prevent excessive immune mediated pathology but on the other hand they may impair clearance of the pathogen. We studied the influence of the inhibitory CD200-CD200R axis on clearance and pathology in two different virus infection models. We find that lack of CD200R signaling strongly enhances type I interferon (IFN) production and viral clearance and improves the outcome of mouse hepatitis corona virus (MHV) infection, particularly in female mice. MHV clearance is known to be dependent on Toll like receptor 7 (TLR7)-mediated type I IFN production and sex differences in TLR7 responses previously have been reported for humans. We therefore hypothesize that CD200R ligation suppresses TLR7 responses and that release of this inhibition enlarges sex differences in TLR7 signaling. This hypothesis is supported by our findings that in vivo administration of synthetic TLR7 ligand leads to enhanced type I IFN production, particularly in female Cd200−/− mice and that CD200R ligation inhibits TLR7 signaling in vitro. In influenza A virus infection we show that viral clearance is determined by sex but not by CD200R signaling. However, absence of CD200R in influenza A virus infection results in enhanced lung neutrophil influx and pathology in females. Thus, CD200-CD200R and sex are host factors that together determine the outcome of viral infection. Our data predict a sex bias in both beneficial and pathological immune responses to virus infection upon therapeutic targeting of CD200-CD200R

    Integrating human and ecosystem health through ecosystem services frameworks

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    The pace and scale of environmental change is undermining the conditions for human health. Yet the environment and human health remain poorly integrated within research, policy and practice. The ecosystem services (ES) approach provides a way of promoting integration via the frameworks used to represent relationships between environment and society in simple visual forms. To assess this potential, we undertook a scoping review of ES frameworks and assessed how each represented seven key dimensions, including ecosystem and human health. Of the 84 ES frameworks identified, the majority did not include human health (62%) or include feedback mechanisms between ecosystems and human health (75%). While ecosystem drivers of human health are included in some ES frameworks, more comprehensive frameworks are required to drive forward research and policy on environmental change and human health

    Self-Reported Time in Bed and Sleep Quality in Association with Internalizing and Externalizing Symptoms in School-Age Youth

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    This study investigated the relationship between self-reported time in bed and sleep quality in association with self-reported internalizing and externalizing symptoms in a sample of 285 elementary school students (52% female) recruited from a rural Midwestern elementary school. Path models were used to estimate proposed associations, controlling for grade level and gender. Curvilinear associations were found between time in bed and anxiety, depressive symptoms, and irritability. Marginal curvilinear trends were found between time in bed and emotion dysregulation, reactive aggression, and proactive aggression. Sleep quality was negatively associated with anxiety, depressive symptoms, irritability, reactive aggression, and delinquency engagement. Gender and grade differences were found across models. Findings suggest that examining self-reported time in bed (both linear and quadratic) and sleep quality is important for understanding internalizing and externalizing symptoms associated with sleep in school-age youth. Incorporating self-reported sleep assessments into clinical practice and school-based evaluations may have implications for a child’s adjustment
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