159 research outputs found

    Ultrastructural changes in chemically induced preneoplastic focal lesions in the rat liver: a stereological study

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    Ultrastructural changes were investigated and quantified, using a stereological approach, in early gamma-glutamyl transpeptidase (GGT)-positive focal lesions, induced in the rat liver by treatment with a single initiating dose of diethylnitrosamine (DENA) followed by promotion with phenobarbitone (PB) for 30 weeks. Within the extra-hepato cyte environment of focal tissue, the mean volume occupied by Ito cells was markedly decreased, whilst that occupied by endothelial and Kupffer cells was increased, when compared to uninvolved tissue from the same rat livers. The bile canalicull were dilated, but nosignificant differences in the mean volume occupkd by the sinusoidal and Disse spaces were noted. In focal hepatocytes there was a striking overproduction of lipid droplets and proliferation of smooth endoplasmic reticulum (sER). Whorls of concentrically arranged, parallel ER membranes were found only in the hepatocytes of preneoplastic foci, in association with the proliferated sER, and never in the surrounding, uninvolved tissue. The Increase In mean volume of the sER, lipid droplet and cytoplasmic matrix compartments, together with the appearance of whorls, were the major contributing factors to the marked hypertrophy seen in focal hepatocytes. The mean volume of the rough endoplasmic reticulum, mitochondrial, lysosomal, peroxisomal and nuclear compartments per hepatocyte also Increased, but contributed to a lesser extent to the cellular hypertrophy. It is speculated that whorls may be structural adaptations, resulting from a possible alteration in the normalfeedback control of cholesterol synthesis, for the production of sterols and the biogenesis of sER in eosinophilic-type focal cells. The significance of changes observed in focal tissue, and the high biological variation noted between foci, is discussed in relation to the hepatocarcinogenic proces

    Family-based obesity prevention for infants: Design of the “Mothers & Others” randomized trial

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    Objective Our goal is to test the efficacy of a family-based, multi-component intervention focused on infants of African-American (AA) mothers and families, a minority population at elevated risk for pediatric obesity, versus a child safety attention-control group to promote healthy weight gain patterns during the first two years of life. Design, participants, and methods The design is a two-group randomized controlled trial among 468 AA pregnant women in central North Carolina. Mothers and study partners in the intervention group receive anticipatory guidance on breastfeeding, responsive feeding, use of non-food soothing techniques for infant crying, appropriate timing and quality of complementary feeding, age-appropriate infant sleep, and minimization of TV/media. The primary delivery channel is 6 home visits by a peer educator, 4 interim newsletters and twice-weekly text messaging. Intervention families also receive 2 home visits from an International Board Certified Lactation Consultant. Assessments occur at 28 and 37 weeks gestation and when infants are 1, 3, 6, 9, 12, and 15 months of age. Results The primary outcome is infant/toddler growth and likelihood of overweight at 15 months. Differences between groups are expected to be achieved through uptake of the targeted infant feeding and care behaviors (secondary outcomes) and change in caregivers' modifiable risk factors (mediators) underpinning the intervention. Conclusions If successful in promoting healthy infant growth and enhancing caregiver behaviors, “Mothers and Others” will have high public health relevance for future obesity-prevention efforts aimed at children younger than 2 years, including interventional research and federal, state, and community health programs. Trial Registration ClinicalTrials.gov, NCT01938118, August 9, 2013

    A monovalent chimpanzee adenovirus Ebola vaccine boosted with MVA

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    BACKGROUND The West African outbreak of Ebola virus disease that peaked in 2014 has caused more than 11,000 deaths. The development of an effective Ebola vaccine is a priority for control of a future outbreak. METHODS In this phase 1 study, we administered a single dose of the chimpanzee adenovirus 3 (ChAd3) vaccine encoding the surface glycoprotein of Zaire ebolavirus (ZEBOV) to 60 healthy adult volunteers in Oxford, United Kingdom. The vaccine was administered in three dose levels — 1×1010 viral particles, 2.5×1010 viral particles, and 5×1010 viral particles — with 20 participants in each group. We then assessed the effect of adding a booster dose of a modified vaccinia Ankara (MVA) strain, encoding the same Ebola virus glyco- protein, in 30 of the 60 participants and evaluated a reduced prime–boost interval in another 16 participants. We also compared antibody responses to inactivated whole Ebola virus virions and neutralizing antibody activity with those observed in phase 1 studies of a recombinant vesicular stomatitis virus–based vaccine expressing a ZEBOV glycoprotein (rVSV-ZEBOV) to determine relative potency and assess durability. RESULTS No safety concerns were identified at any of the dose levels studied. Four weeks after immunization with the ChAd3 vaccine, ZEBOV-specific antibody responses were similar to those induced by rVSV-ZEBOV vaccination, with a geometric mean titer of 752 and 921, respectively. ZEBOV neutralization activity was also similar with the two vaccines (geo- metric mean titer, 14.9 and 22.2, respectively). Boosting with the MVA vector increased virus-specific antibodies by a factor of 12 (geometric mean titer, 9007) and increased glycoprotein-specific CD8+ T cells by a factor of 5. Significant increases in neutralizing antibodies were seen after boosting in all 30 participants (geometric mean titer, 139; P<0.001). Virus-specific antibody responses in participants primed with ChAd3 remained positive 6 months after vaccination (geometric mean titer, 758) but were significantly higher in those who had received the MVA booster (geometric mean titer, 1750; P<0.001). CONCLUSIONS The ChAd3 vaccine boosted with MVA elicited B-cell and T-cell immune responses to ZEBOV that were superior to those induced by the ChAd3 vaccine alone. (Funded by the Wellcome Trust and others; ClinicalTrials.gov number, NCT02240875.

    Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

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    BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

    Search for Gravitational Waves Associated with Gamma-Ray Bursts Detected by Fermi and Swift during the LIGO-Virgo Run O3b

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    We search for gravitational-wave signals associated with gamma-ray bursts (GRBs) detected by the Fermi and Swift satellites during the second half of the third observing run of Advanced LIGO and Advanced Virgo (2019 November 1 15:00 UTC-2020 March 27 17:00 UTC). We conduct two independent searches: A generic gravitational-wave transients search to analyze 86 GRBs and an analysis to target binary mergers with at least one neutron star as short GRB progenitors for 17 events. We find no significant evidence for gravitational-wave signals associated with any of these GRBs. A weighted binomial test of the combined results finds no evidence for subthreshold gravitational-wave signals associated with this GRB ensemble either. We use several source types and signal morphologies during the searches, resulting in lower bounds on the estimated distance to each GRB. Finally, we constrain the population of low-luminosity short GRBs using results from the first to the third observing runs of Advanced LIGO and Advanced Virgo. The resulting population is in accordance with the local binary neutron star merger rate. © 2022. The Author(s). Published by the American Astronomical Society

    Narrowband Searches for Continuous and Long-duration Transient Gravitational Waves from Known Pulsars in the LIGO-Virgo Third Observing Run

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    Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully coherent search for such signals from eighteen pulsars in data from LIGO and Virgo's third observing run (O3). For known pulsars, efficient and sensitive matched-filter searches can be carried out if one assumes the gravitational radiation is phase-locked to the electromagnetic emission. In the search presented here, we relax this assumption and allow both the frequency and the time derivative of the frequency of the gravitational waves to vary in a small range around those inferred from electromagnetic observations. We find no evidence for continuous gravitational waves, and set upper limits on the strain amplitude for each target. These limits are more constraining for seven of the targets than the spin-down limit defined by ascribing all rotational energy loss to gravitational radiation. In an additional search, we look in O3 data for long-duration (hours-months) transient gravitational waves in the aftermath of pulsar glitches for six targets with a total of nine glitches. We report two marginal outliers from this search, but find no clear evidence for such emission either. The resulting duration-dependent strain upper limits do not surpass indirect energy constraints for any of these targets. © 2022. The Author(s). Published by the American Astronomical Society

    Factors affecting body temperatures of toads

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    Factors influencing levels and rates of variation of body temperature ( T b ) in montane Bufo boreas boreas and in lowland Bufo boreas halophilus were investigated as an initial step toward understanding the role of natural thermal variation in the physiology and energetics of these ectothermic animals. Body temperatures of boreas can vary 25–30° C over 24-h periods. Such variation is primarily due to both nocturnal and diurnal activity and the physical characteristics of the montane environment. Bufo boreas halophilus are primarily nocturnal except during breeding and are voluntarily active at body temperatures ranging between 10 and 25° C. Despite variation in T b encountered in the field, boreas select a narrow range of T b in a thermal gradient, averaging 23.5 and 26.2° C for fasted individuals maintained under field conditions or acclimated to 20° C, respectively. In a thermal gradient the mean T b of fasted halophilus acclimated to 20° C is 23.9° C. Skin color of boreas varies in the field from very dark to light. The dark skins absorb approximately 4% more radiation than the light ones. Light colored boreas should absorb approximately 5% more radiation than similarly colored halophilus . Evaporative water losses increase directly with skin temperatures and vapor pressure deficit in both subspecies. Larger individuals heat and cool more slowly than smaller ones. Calculation of an enery budget for boreal toads suggests that they could sit in direct sunlight for long periods without fatally overheating, providing the skin was continually moist.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47722/1/442_2004_Article_BF00344732.pd
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