1,727 research outputs found
Refinement in Laboratory Animal Science: Is it a Cinderella subject, and is there conflict and imbalance within the 3 Rs?
No abstract availabl
The CDVPlex biometric cinema: sensing physiological responses to emotional stimuli in film
We describe a study conducted to investigate the potential
correlations between human subject responses to emotional stimuli in movies, and observed biometric responses. The experimental set-up and procedure are described, including details of the range of sensors used to detect and record observed physiological data (such as heart-rate, galvanic skin response, body temperature and movement). Finally, applications and future analysis of the results of the study are discussed
Influence of husbandry procedures on mouse locomotor activity
The currently used raL models of obesity and diabetes are derived from either Zucker or from Koletsky rats. Recently, we identified a spontaneous obese rat from out Wistar colony which is maintained as an inbred stock for the past 75 years. Initially, one of the male progeny in a litter was observed to have abnormal body weight for its age. The parents of this ral were identified, the progeny selectively bred, and a colony has been developed. This is designated as WNIN-0b. The colony is maintained by mating heterozygous animals (+/ob), as the homozygous (ob/ob) were found to be infertile. The trait is carried as an autosomal recessive mutation and the colony is currenfly in F7 generation.Obesity is visible in these mutants around 35 days of age. They are hyperphagic and reach a body weight of 500—600 g by 105 days of age. “Kinky” tail is characteristic of this mutant and this is visible around 50-60 days. Sexual maturity is delayed in female obese mutants, as judged by the day of vaginal opening. The animals are cuglyccmic and show hyperinsulinaemia, hypertriglyceridaemia, arid hypercholesterolemia. Another mutant showing hyperglycemia is also obtained fromthe obese colony. Unlike earlier models which are essentially derived from a randomAbred stock, this is the first report of a rat obese model, developed spontaneously from an inbred strain
Repeated stressors in adulthood increase the rate of biological ageing
Background
Individuals of the same age can differ substantially in the degree to which they have accumulated tissue damage, akin to bodily wear and tear, from past experiences. This accumulated tissue damage reflects the individual’s biological age and may better predict physiological and behavioural performance than the individual‘s chronological age. However, at present it remains unclear how to reliably assess biological age in individual wild vertebrates.
Methods
We exposed hand-raised adult Eurasian blackbirds (Turdus merula) to a combination of repeated immune and disturbance stressors for over one year to determine the effects of chronic stress on potential biomarkers of biological ageing including telomere shortening, oxidative stress load, and glucocorticoid hormones. We also assessed general measures of individual condition including body mass and locomotor activity.
Results
By the end of the experiment, stress-exposed birds showed greater decreases in telomere lengths. Stress-exposed birds also maintained higher circulating levels of oxidative damage compared with control birds. Other potential biomarkers such as concentrations of antioxidants and glucocorticoid hormone traits showed greater resilience and did not differ significantly between treatment groups.
Conclusions
The current data demonstrate that repeated exposure to experimental stressors affects the rate of biological ageing in adult Eurasian blackbirds. Both telomeres and oxidative damage were affected by repeated stress exposure and thus can serve as blood-derived biomarkers of biological ageing.</p
The limits of the rotating wave approximation in the electromagnetic field propagation in a cavity
We consider three two-level atoms inside a one-dimensional cavity,
interacting with the electromagnetic field in the rotating wave approximation
(RWA), commonly used in the atom-radiation interaction. One of the three atoms
is initially excited, and the other two are in their ground state. We
numerically calculate the propagation of the field spontaneously emitted by the
excited atom and scattered by the second atom, as well as the excitation
probability of the second and third atom. The results obtained are analyzed
from the point of view of relativistic causality in the atom-field interaction.
We show that, when the RWA is used, relativistic causality is obtained only if
the integrations over the field frequencies are extended to ; on the
contrary, noncausal tails remain even if the number of field modes is
increased. This clearly shows the limit of the RWA in dealing with subtle
problems such as relativistic causality in the atom-field interaction.Comment: 13 pages, 6 figure
Derivations of Atomic Ionization Effects Induced by Neutrino Magnetic Moments
A recent paper [M.B. Voloshin, Phys. Rev. Lett. 105, 201801 (2010)] pointed
out that our earlier derivations of atomic ionization cross-section due to
neutrino magnetic moments (arXiv:1001.2074v2) involved unjustified assumptions.
We confirm and elaborate on this comment with these notes. We caution that the
results of the sum-rule approach in this paper contradict the expected
behaviour in atomic transitions.Comment: V3 3 pages ; confirm and elaborate on unjustified assumptions in V1 &
V
Immunospecific Antibody Concentration in Egg Yolk of Chickens Orally Immunised with Varying Doses of Bovine Serum Albumin and the Mucosal Adjuvant, RhinoVax®, using Different Immunization Regimes
Antibody harvested from eggs of immunised chickens, IgY, has proven to be a non-invasive alternative to antibodies purified from serum of mammals. Taking the non-invasive concept further, the development of oral immunization techniques combined with IgY harvest from chicken eggs may subsequently eliminate all regulated procedures from polyclonal antibody production. In the present study, we report the effects of varying the temporal administration mode of the antigen (immunogen) comparing dosing on three consecutive days with dosing on five consecutive days, and of incorporating a mucosal adjuvant. Two antigen doses were compared: 30 mg bovine serum albumin (BSA) and 300 mg BSA, with and without the mucosal adjuvant, RhinoVax®, administered to laying chickens. The egg yolk of chickens dosed with BSA in combination with 20% RhinoVax®, contained significantly higher concentrations of immunospecific IgY than did egg yolks of chickens fed with BSA without adjuvant. The most efficient dose in the RhinoVax®-treated groups was 300 mg BSA regardless of whether the chickens were initially immunised daily for three or five days. A 3-day dosing regime with BSA alone also induced immunospecific IgY production. This study confirms that RhinoVax® is an efficient oral adjuvant. It also demonstrates the efficacy of daily immunizations on three or five consecutive days on immunospecific IgY production. The chickens received oral booster immunizations one and two months after the initial immunization. No real effect could be recorded after the second and third immunization, although the study did provide some evidence of memory based on an optimum IgY concentration recorded after the 2nd immunization.
Ovarian hormones and pituitary responsiveness to gonadotrophin releasing hormone in mice
In the present study the role of progesterone and oestradiol in modulating the responsiveness at the anterior pituitary gland to gonadotrophin releasing hormone (GN-RH) was investigated by measuring the release of luteinizing hormone (LH) in ovariectomised mice which had been pretreated with these steroids.A significant release of LH was seen in the animals receiving GN-RH. Pretreatment with oestrogen and progesterone depressed LH levels in the animals which did not receive GN-RH, and resulted in a larger release of LH in the animals receiving GN-RH in comparison with the control group pretreated with oil
Is it necessary to soak rice grains to prepare Rhizoctonia solani AG-4 inoculum?
A study was conducted to evaluate the effects on the development of root rot on common bean, cv. 'Dufrix' after treatment with four volumes of water (0, 30%, 60%, and 90%, v/w) added to rice grains previously immersed in water for 24 hours before autoclaving and colonization of grains by Rhizoctonia solani AG-4. Colonized rice grains and non-infested rice grains were mixed in pots with sterilized soil and sand (2:1), where beans were sown. Based on results of area under plant emergence curve, plant height, plant dry weight, and disease severity, we conclude that inoculum is more effective in causing disease when no water is added to the rice grains before autoclaving.CNPqFAPEMI
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