871 research outputs found
Effect of Transplanting Suprachiasmatic Nuclei from Donors of Different Ages into Completely SCN Lesioned Hamsters
The suprachiasmatic nucleus (SCN) is the
primary circadian pacemaker in mammals.
Ralph and colleagues/14/provided recent new
evidence for this by transplanting SCNs between
golden hamsters with different genetically
determined periods and producing circadian
rhythmsof running wheel activity with periods
characteristic of the donor. We have extended
these studies in order to evaluate the age range
of donor tissue that can be used for transplantation.
SCN of hamsters from embryonic day 11
through postnatal day 12 can serve as functional
grafts to restore rhythmicity to arrhythmic SCN
lesioned animals. The time between SCN transplantation
and onset of rhythmicity does not
depend on the age of the donor. The presence of
patches containing vasoactive intestinal peptide
(VIP) immunoreactive cells is a good indicator
of graft success, while its absence is correlated
with a lack of transplant effect. The 18 day span
during which SCN tissue can be harvested for
transplantation should expand the uses to which
this technique can be put. Our results also
suggest that it would be advantageous to
examine the age range of neural tissue that ca’n
be used in other transplantation models
Aunt Sallie\u27s Lament (Altered)
[24] pages : mounted color illustrations. Limited edition of 120 copies signed by Claire Van Vliet, Mary Richardson, Audrey Holden and E.D. Levitt. This edition was made using the Permalin text block of the 1993 edition by Chronicle Books ... The design was made with Ellen Dorn Levitt and Audrey Holden who did most of the assembly and made the boxes with Mary Richardson. --Colophon. Book bound in a diamond-shape with the left point blunted for the spine. Each page is a different combination of colors and geometric shapes resembling quilt blocks. Additional Japanese and handmade papers added to this edition. Issued in a drop-spine box (31 cm.) covered with quilt-type fabric. Library has copy no. 48.https://digitalcommons.risd.edu/specialcollections_artistsbooks/1582/thumbnail.jp
Effects of Tibolone Metabolites on Human Endometrial Cell Lines in Co-culture
In human endometrium, cell proliferation is regulated by ovarian steroids through heterotypic interactions between stromal and epithelial cells populating this tissue. We tested the proliferative effects of tibolone and its metabolites using endometrial co-cultures that mimic the normal proliferative response to hormones. We found that both the Δ4-tibolone metabolite and the pure progestin ORG2058 counteract estradiol-driven epithelial cell proliferation. Surprisingly, the estrogen receptor binding 3-hydroxyl-metabolites of tibolone also counteracted estradiol-driven proliferation. Inhibition of proliferation by 3β-OH-tibolone was abrogated by low doses of the progesterone receptor antagonist mifepristone, This suggests that 3β-OH-tibolone is converted to a progestagenic metabolite. We found that the stromal cells used in the co-cultures express high levels of the ketosteroid dehydrogenase, AKR1C2, which is able to oxidize 3β-OH-tibolone back to tibolone. Thus the unexpected progestagenic effect of 3β-OH-tibolone in these co-cultures may be due to metabolic activity present in the stromal cells of the co-cultures
Transforming growth factor and intercellular communication in tubular epithelial cells: a role in diabetic nephropathy.
Aims: Changes in cell-to-cell communication have been linked to several secondary complications of diabetes, including diabetic nephropathy. This study examines a role for glucose-evoked changes in the beta1 isoform of the pro-fibrotic cytokine transforming growth factor (TGFβ1), on connexin expression, gap-junction mediated intercellular communication and hemi-channel mediated ATP release from epithelial cells of the proximal tubule.
Methods: Connexin-26 and connexin-43 expression was assessed by immunoblot analysis in human kidney (HK2) tubular epithelial cells treated with TGFβ1 (2-10ng/mL) for 48hrs. Whole cell paired-patch electrophysiology assessed junctional conductance between TGFβ1 treated HK2 cells. Hemi-channel opening was determined by carboxyfluorescein uptake, whilst bio-sensing was used to determine real-time ATP release.
Results: Immunoblotting confirmed that TGFβ1 down-regulates connexin-26 to 72.7±13.3%, 71.6±4.8%, and 58.3±5.7% of control and connexin-43 to 61.2±10.4%, 49.5±6.1%, and 48.1±3.8% at 2, 4 and 10 ng/mL respectively. TGFβ1 significantly decreased junctional conductance at 48hrs (1.15±0.9nS compared to 4.5±1.3nS in control cells n=5; P<0.05), whilst carboxyfluorescein uptake increased 346±33% in TGFβ1-treated (10ng/mL) cells. A response inhibited by the hemi-channel blocker carbenoxolone (200µM, 30mins). Bio-sensing confirmed that increased channel opening was paralleled by elevated ATP release following 48hr TGFβ1 treatment (1.99±0.47µM compared to a control 0.29± 0.06µM, P<0.01, n=3).
Conclusions: The current study suggests that acute 48hr application of the pro-fibrotic cytokine reduces connexin-mediated intercellular communication in proximal tubular epithelial cells in favour of hemi-channel mediated ATP release. The rise in intercellular ATP may contribute to tubular fibrosis in the diabetic kidney.
Acknowledgement: This work is supported by Diabetes UK (BDA:11/0004215, BDA:16/0005427
Endoplasmic reticulum stress disrupts placental morphogenesis: implications for human intrauterine growth restriction.
We recently reported the first evidence of placental endoplasmic reticulum (ER) stress in the pathophysiology of human intrauterine growth restriction. Here, we used a mouse model to investigate potential underlying mechanisms. Eif2s1(tm1RjK) mice, in which Ser51 of eukaryotic initiation factor 2 subunit alpha (eIF2α) is mutated, display a 30% increase in basal translation. In Eif2s1(tm1RjK) placentas, we observed increased ER stress and anomalous accumulation of glycoproteins in the endocrine junctional zone (Jz), but not in the labyrinthine zone where physiological exchange occurs. Placental and fetal weights were reduced by 15% (97 mg to 82 mg, p < 0.001) and 20% (1009 mg to 798 mg, p < 0.001), respectively. To investigate whether ER stress affects bioactivity of secreted proteins, mouse embryonic fibroblasts (MEFs) were derived from Eif2s1(tm1RjK) mutants. These MEFs exhibited ER stress, grew 50% slower, and showed reduced Akt-mTOR signalling compared to wild-type cells. Conditioned medium (CM) derived from Eif2s1(tm1RjK) MEFs failed to maintain trophoblast stem cells in a progenitor state, but the effect could be rescued by exogenous application of FGF4 and heparin. In addition, ER stress promoted accumulation of pro-Igf2 with altered glycosylation in the CM without affecting cellular levels, indicating that the protein failed to be processed after release. Igf2 is the major growth factor for placental development; indeed, activity in the Pdk1-Akt-mTOR pathways was decreased in Eif2s1(tm1RjK) placentas, indicating loss of Igf2 signalling. Furthermore, we observed premature differentiation of trophoblast progenitors at E9.5 in mutant placentas, consistent with the in vitro results and with the disproportionate development of the labyrinth and Jz seen in placentas at E18.5. Similar disproportion has been reported in the Igf2-null mouse. These results demonstrate that ER stress adversely affects placental development, and that modulation of post-translational processing, and hence bioactivity, of secreted growth factors contributes to this effect. Placental dysmorphogenesis potentially affects fetal growth through reduced exchange capacity
Using the COMMVAC taxonomy to map vaccination communication interventions in Mozambique
Improved communication about childhood vaccination is fundamental to increasing vaccine uptake in low-income countries. Mozambique, with 64% of children fully vaccinated, uses a range of communication interventions to promote uptake of childhood immunisation.; Using a taxonomy developed by the 'Communicate to Vaccinate' (COMMVAC) project, the study aims to identify and classify the existing communication interventions for vaccination in Mozambique and to find the gaps.; We used a qualitative research approach to identify the range of communication interventions used in Mozambique. In-depth semi-structured interviews were carried out with key purposively selected personnel at national level and relevant documents were collected and analysed. These data were complemented with observations of communication during routine vaccination and campaigns in Nampula province. We used the COMMVAC taxonomy, which organises vaccination communication intervention according to its intended purpose and the population targeted, to map both routine and campaign interventions.; We identified interventions used in campaign and routine vaccination, or in both, fitting five of the seven taxonomy purposes, with informing or educating community members predominating. We did not identify any interventions that aimed to provide support or facilitate decision-making. There were interventions for all main target groups, although fewer for health providers. Overlap occurred: for example, interventions often targeted both parents and community members.; We consider that the predominant focus on informing and educating community members is appropriate in the Mozambican context, where there is a high level of illiteracy and poor knowledge of the reasons for vaccination. We recommend increasing interventions for health providers, in particular training them in better communication for vaccination. The taxonomy was useful for identifying gaps, but needs to be more user-friendly if it is to be employed as a tool by health service managers
Genistein effects on stromal cells determines epithelial proliferation in endometrial co-cultures
Estrogen is the leading etiologic factor for endometrial cancer. Estrogen-induced proliferation of endometrial epithelial cells normally requires paracrine growth factors produced by stromal cells. Epidemiologic evidence indicates that dietary soy prevents endometrial cancer, and implicates the phytoestrogen genistein in this effect. However, results from previous studies are conflicting regarding the effects of genistein on hormone responsive cancers
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Relation between Retinopathy and Progression of Coronary Artery Calcium in Individuals with Versus Without Diabetes Mellitus (From the Multi-Ethnic Study of Atherosclerosis).
Retinopathy is a microvascular complication of diabetes mellitus (DM); however, it is also increasingly recognized in persons without DM. The microvascular diseases may play a prominent role in coronary heart disease (CHD) development in individuals with DM. We performed the study to evaluate the relation between non-DM retinopathy and CHD and also the association between baseline retinopathy and incidence and progression of CHD in individuals with and without DM. We included 5709 subjects with and without DM from the Multi-Ethnic Study of Atherosclerosis, who had retinal photos and coronary artery calcium score (CACS) available. We studied the association between baseline retinopathy and incidence and progression of coronary artery calcification (CAC) in subjects with and without DM. In DM group, the presence of retinopathy was significantly associated with an increased rate of CAC (RR 1.3 (95% CI [1.02, 1.66]) after adjusting for age, sex, race, follow-up time, and CHD risk factors. In non-DM group, the presence of retinopathy was not significantly associated with increased risk of CAC, however, the interaction between presence of retinopathy and DM status was not statistically significant. Within the DM group with CAC present at baseline, the presence of retinopathy was significantly associated with greater CAC progression (113 Agatson units (AU) greater, (95% CI [51-174]). In the non-DM group with present CAC at baseline; the presence of retinopathy was associated with 24 (95% CI [-0.69, 48.76]) AU higher CAC progression. All findings were adjusted for CHD risk factors. In conclusion, after adjustment for major CHD risk factors, retinopathy was associated with progression of CAC in both DM and non-DM individuals. However, the association was stronger in those with DM
Perceptions and experiences of childhood vaccination communication strategies among caregivers and health workers in Nigeria: a qualitative study
Effective vaccination communication with parents is critical in efforts to overcome barriers to childhood vaccination, tackle vaccine hesitancy and improve vaccination coverage. Health workers should be able to provide information to parents and other caregivers and support them in reaching decisions about vaccinating their children. Limited information exists regarding the perceptions of caregivers and health workers on the vaccination communication strategies employed in Nigeria. This study, which forms part of the 'Communicate to vaccinate' (COMMVAC) project, aims to explore the perceptions and experiences of caregivers and health workers in Nigeria on vaccination communication strategies implemented in their settings.; We conducted the study in two States: Bauchi in Northern Nigeria and Cross River in the south. We carried out observations (n = 40), in-depth interviews (n = 14) and focus group discussions (FGDs) (n = 12) amongst 14 purposively selected health workers, two community leaders and 84 caregivers in the two states. We transcribed data verbatim and analysed the data using a framework analysis approach.; Caregivers were informed about vaccination activities through three main sources: health facilities (during health education sessions conducted at antenatal or immunization clinics); media outlets; and announcements (in churches/mosques, communities and markets). Caregivers reported that the information received was very useful. Their preferred sources of information included phone text messages, town announcers, media and church/mosque announcements. Some caregivers perceived the clinic environment, long waiting times and health worker attitudes as barriers to receiving vaccination information.When delivering communication interventions, health workers described issues tied to poor communication skills; poor motivation; and attitudes of community members, including vaccine resistance.; Communication about vaccination involves more than the message but is also influenced by the environment and the attitudes of the deliverer and receiver. It is pertinent for health policy makers and programme managers to understand these factors so as to effectively implement communication approaches
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