Dosage compensation in birds

AbstractThe Z and W sex chromosomes of birds have evolved independently from the mammalian X and Y chromosomes [1]. Unlike mammals, female birds are heterogametic (ZW), while males are homogametic (ZZ). Therefore male birds, like female mammals, carry a double dose of sex-linked genes relative to the other sex. Other animals with nonhomologous sex chromosomes possess “dosage compensation” systems to equalize the expression of sex-linked genes. Dosage compensation occurs in animals as diverse as mammals, insects, and nematodes, although the mechanisms involved differ profoundly [2]. In birds, however, it is widely accepted that dosage compensation does not occur [3–5], and the differential expression of Z-linked genes has been suggested to underlie the avian sex-determination mechanism [6]. Here we show equivalent expression of at least six of nine Z chromosome genes in male and female chick embryos by using real-time quantitative PCR [7]. Only the Z-linked ScII gene, whose ortholog in Caenorhabditis elegans plays a crucial role in dosage compensation [8], escapes compensation by this assay. Our results imply that the majority of Z-linked genes in the chicken are dosage compensated

Managing Adult-onset Still's disease: The effectiveness of high-dosage of corticosteroids as first-line treatment in inducing the clinical remission. Results from an observational study

To assess the effectiveness of the treatment with high dosage of corticosteroids (CCSs), as first-line therapy, in inducing remission in naïve Adult-onset Still's disease (AOSD) patients compared with low dosage of CCSs, after 6 months. To further evaluate the rate of patients maintaining the remission and the rate of CCSs discontinuation, after additional 12 months of follow-up.A retrospective evaluation of patients prospectively followed was designed to compare the rate of clinical remission in naïve AOSD patients treated with high dosages of CCSs (0.8-1 mg/kg/day of prednisone-equivalent) or low dosage of CCSs (0.2-0.3 mg/kg/day of prednisone-equivalent), after 6 months. An additional analysis was performed to compare the rate of monocyclic pattern between these groups, after further 12 months of follow-up.The clinical remission was achieved in a higher percentage of patients treated with the first-line treatment with high dosage of CCSs than treated the first-line treatment with low dosage of CCSs. At the end of 18 months of follow-up, a larger percentage of patients treated the first-line treatment with high dosage of CCSs was classified as monocyclic pattern and discontinued CCSs when compared with patients treated the first-line treatment with low dosage of CCSs. Patients defined as CCSs non-responder were treated with methotrexate (MTX)+CCSs or with combination therapy CCSs+MTX+biologic drug. The clinical remission was observed in a percentage of these patients.We showed the effectiveness of the first-line treatment with high dosage of CCSs in inducing clinical remission in naïve AOSD patients when compared with the first-line treatment with low dosage of CCSs. The first-line treatment with high dosage of CCSs was also associated with the achievement of monocyclic pattern and CCSs discontinuation, after 18 months of follow-up

A computer program for evaluating propellant heating and radiation dosage to crews of nuclear-powered rocket vehicles

Program evaluates propellant heating in a nuclear rocket stage. Program code employs infinite-medium buildup factors to calculate gamma dosage and employs the Albert-Welton kernal to calculate the fast neutron dosage

Beyond the pill: New medication delivery options for ADHD

Successful treatment of pediatric disorders has necessitated the development of alternative medication formulations, as children may prefer alternative dosage forms to tablets or capsules. This is especially true for attention-deficit/hyperactivity disorder (ADHD), which is one of the most common chronic pediatric conditions and often involves children with a variety of overlapping physical, psychological, or neurodevelopmental disorders. A special challenge for developing alternative dosage forms for ADHD treatment is the incorporation of a once-daily long-acting formulation. Traditional ADHD medication formulations have been limited, and issues surrounding prescribed dosing regimens—including poor medication adherence, difficulty swallowing, and the lack of dosing titration options—persist in ADHD treatment. In other disease areas, the development of alternative formulations has provided options for patients who have issues with consuming solid dosage forms, particularly children and individuals with developmental disorders. In the light of these new developments, several alternative formulations for ADHD medications are under development or have recently become available. This article reviews the various strategies for developing alternative dosage forms in other disease areas and discusses the application of these strategies in ADHD treatment. Alternative dosage forms may increase medication adherence, compliance, and patient preference and, therefore, improve the overall treatment for ADHD.</jats:p

Rupture Test and Bioavailability of Oil-Soluble Vitamins

In lieu of an abstract, here is the article\u27s first paragraph: Bioavailability of multi-vitamins as dietary supplements has always been a concern. Dissolution studies have been successfully used to predict drug release of bioactive molecules, but with vitamins there are some exceptions. United State Pharmacopoeia (USP) defines the dissolution requirements of multi-vitamin supplements based on the composition and type of dosage form. As oil-soluble vitamins do not meet the criterion of “dissolution”, the performance of dosage forms containing such vitamins is evaluated by disintegration studies primarily. Dissolution studies are not applicable for such dosage forms [1]