883 research outputs found

    Studying Cat (Felis catus) Diabetes: Beware of the Acromegalic Imposter

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    Naturally occurring diabetes mellitus (DM) is common in domestic cats (Felis catus). It has been proposed as a model for human Type 2 DM given many shared features. Small case studies demonstrate feline DM also occurs as a result of insulin resistance due to a somatotrophinoma. The current study estimates the prevalence of hypersomatotropism or acromegaly in the largest cohort of diabetic cats to date, evaluates clinical presentation and ease of recognition. Diabetic cats were screened for hypersomatotropism using serum total insulin-like growth factor-1 (IGF-1; radioimmunoassay), followed by further evaluation of a subset of cases with suggestive IGF-1 (>1000 ng/ml) through pituitary imaging and/ or histopathology. Clinicians indicated pre-test suspicion for hypersomatotropism. In total 1221 diabetic cats were screened; 319 (26.1%) demonstrated a serum IGF-1>1000 ng/ml (95% confidence interval: 23.6-28.6%). Of these cats a subset of 63 (20%) underwent pituitary imaging and 56/63 (89%) had a pituitary tumour on computed tomography; an additional three on magnetic resonance imaging and one on necropsy. These data suggest a positive predictive value of serum IGF-1 for hypersomatotropism of 95% (95% confidence interval: 90-100%), thus suggesting the overall hypersomatotropism prevalence among UK diabetic cats to be 24.8% (95% confidence interval: 21.2-28.6%). Only 24% of clinicians indicated a strong pre-test suspicion; most hypersomatotropism cats did not display typical phenotypical acromegaly signs. The current data suggest hypersomatotropism screening should be considered when studying diabetic cats and opportunities exist for comparative acromegaly research, especially in light of the many detected communalities with the human disease

    Hybridization and speciation in angiosperms: a role for pollinator shifts?

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    The majority of convincingly documented cases of hybridization in angiosperms has involved genetic introgression between the parental species or formation of a hybrid species with increased ploidy; however, homoploid (diploid) hybridization may be just as common. Recent studies, including one in BMC Evolutionary Biology, show that pollinator shifts can play a role in both mechanisms of hybrid speciation

    Interleukin-1 polymorphisms associated with increased risk of gastric cancer

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    Helicobacter pylori infection is associated with a variety of clinical outcomes including gastric cancer and duodenal ulcer disease. The reasons for this variation are not clear, but the gastric physiological response is influenced by the severity and anatomical distribution of gastritis induced by H. pylori. Thus, individuals with gastritis predominantly localized to the antrum retain normal (or even high) acid secretion, whereas individuals with extensive corpus gastritis develop hypochlorhydria and gastric atrophy, which are presumptive precursors of gastric cancer. Here we report that interleukin-1 gene cluster polymorphisms suspected of enhancing production of interleukin-1-beta are associated with an increased risk of both hypochlorhydria induced by H. pylori and gastric cancer. Two of these polymorphism are in near-complete linkage disequilibrium and one is a TATA-box polymorphism that markedly affects DNA-protein interactions in vitro. The association with disease may be explained by the biological properties of interleukin-1-beta, which is an important pro-inflammatory cytokine and a powerful inhibitor of gastric acid secretion. Host genetic factors that affect interleukin-1-beta may determine why some individuals infected with H. pylori develop gastric cancer while others do no

    Degeneracy: a link between evolvability, robustness and complexity in biological systems

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    A full accounting of biological robustness remains elusive; both in terms of the mechanisms by which robustness is achieved and the forces that have caused robustness to grow over evolutionary time. Although its importance to topics such as ecosystem services and resilience is well recognized, the broader relationship between robustness and evolution is only starting to be fully appreciated. A renewed interest in this relationship has been prompted by evidence that mutational robustness can play a positive role in the discovery of adaptive innovations (evolvability) and evidence of an intimate relationship between robustness and complexity in biology. This paper offers a new perspective on the mechanics of evolution and the origins of complexity, robustness, and evolvability. Here we explore the hypothesis that degeneracy, a partial overlap in the functioning of multi-functional components, plays a central role in the evolution and robustness of complex forms. In support of this hypothesis, we present evidence that degeneracy is a fundamental source of robustness, it is intimately tied to multi-scaled complexity, and it establishes conditions that are necessary for system evolvability

    The catch 22 of condoms in US correctional facilities

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    <p>Abstract</p> <p>Background</p> <p>Despite the high prevalence of sexually transmitted infections (STIs) and HIV infection in US correctional settings, most jails and prisons in the United States prevent inmates from using condoms to prevent STIs/HIV.</p> <p>Discussion</p> <p>This article makes the following arguments to justify a scalable and feasible next step in the prevention of HIV/STIs among inmates: condoms are a basic and essential part of HIV/STI prevention, HIV/STI transmission occurs in the context of corrections, and several model programs show the feasibility of condom distribution in prisons. A lower end estimate for HIV incidence among incarcerated applied to 2,000,000 new inmates annually results in thousands of new HIV infections acquired each year in corrections that could be prevented with condoms in corrections facilities. Programs from parts of the United States, Canada, and much of Europe show how programs distributing condoms in correctional facilities can be safe and effective.</p> <p>Summary</p> <p>Public health and corrections officials must work together to ensure that condoms and broader sexual disease prevention programs are integrated into US jail and prison health systems.</p

    Bordetella pertussis Infection or Vaccination Substantially Protects Mice against B. bronchiseptica Infection

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    Although B. bronchiseptica efficiently infects a wide range of mammalian hosts and efficiently spreads among them, it is rarely observed in humans. In contrast to the many other hosts of B. bronchiseptica, humans are host to the apparently specialized pathogen B. pertussis, the great majority having immunity due to vaccination, infection or both. Here we explore whether immunity to B. pertussis protects against B. bronchiseptica infection. In a murine model, either infection or vaccination with B. pertussis induced antibodies that recognized antigens of B. bronchiseptica and protected the lower respiratory tract of mice against three phylogenetically disparate strains of B. bronchiseptica that efficiently infect naïve animals. Furthermore, vaccination with purified B. pertussis-derived pertactin, filamentous hemagglutinin or the human acellular vaccine, Adacel, conferred similar protection against B. bronchiseptica challenge. These data indicate that individual immunity to B. pertussis affects B. bronchiseptica infection, and suggest that the high levels of herd immunity against B. pertussis in humans could explain the lack of observed B. bronchiseptica transmission. This could also explain the apparent association of B. bronchiseptica infections with an immunocompromised state

    Assessing the reliability of retrospective reports of adverse childhood experiences among adolescents with documented childhood maltreatment

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    The literature suggests that childhood maltreatment is related to a higher probability of developing psychopathology and disease in adulthood. However, some authors have questioned the reliability of self-reports of maltreatment, suggesting that psychopathology at the time of evaluation affects self-reports. We evaluated the reliability of the self-reports of 79 young adults who were identified in childhood by Child Protective Services by comparing two moments of evaluation. Psychological and physical symptoms were tested to evaluate their interference with the reports. We found good to excellent agreement, with no significant correlation between the changes in self-reported experiences and the changes in physical and psychological symptoms, suggesting that the reliability of reports is not related to the health state at the time of the report

    Temporal and Spatial Profiling of Root Growth Revealed Novel Response of Maize Roots under Various Nitrogen Supplies in the Field

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    A challenge for Chinese agriculture is to limit the overapplication of nitrogen (N) without reducing grain yield. Roots take up N and participate in N assimilation, facilitating dry matter accumulation in grains. However, little is known about how the root system in soil profile responds to various N supplies. In the present study, N uptake, temporal and spatial distributions of maize roots, and soil mineral N (Nmin) were thoroughly studied under field conditions in three consecutive years. The results showed that in spite of transient stimulation of growth of early initiated nodal roots, N deficiency completely suppressed growth of the later-initiated nodal roots and accelerated root death, causing an early decrease in the total root length at the rapid vegetative growth stage of maize plants. Early N excess, deficiency, or delayed N topdressing reduced plant N content, resulting in a significant decrease in dry matter accumulation and grain yield. Notably, N overapplication led to N leaching that stimulated root growth in the 40–50 cm soil layer. It was concluded that the temporal and spatial growth patterns of maize roots were controlled by shoot growth and local soil Nmin, respectively. Improving N management involves not only controlling the total amount of chemical N fertilizer applied, but also synchronizing crop N demand and soil N supply by split N applications
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