An orphan gene is necessary for preaxial digit formation during salamander limb development

Limb development in salamanders differs from other tetrapods in that the first digits to form are the two most anterior (preaxial dominance). This has been proposed as a salamander novelty and its mechanistic basis is unknown. Salamanders are the only adult tetrapods able to regenerate the limb, and the contribution of preaxial dominance to limb regeneration is unclear. Here we show that during early outgrowth of the limb bud, a small cohort of cells express the orphan gene Prod1 together with Bmp2, a critical player in digit condensation in amniotes. Disruption of Prod1 with a gene-editing nuclease abrogates these cells, and blocks formation of the radius and ulna, and outgrowth of the anterior digits. Preaxial dominance is a notable feature of limb regeneration in the larval newt, but this changes abruptly after metamorphosis so that the formation of anterior and posterior digits occurs together within the autopodium resembling an amniote-like pattern

Catabolic and proinflammatory effects of leptin in chondrocytes are regulated by suppressor of cytokine signaling-3

BACKGROUND: Previous studies provide evidence that adipokine leptin increases production of catabolic and proinflammatory factors in chondrocytes and serves as a link between obesity and osteoarthritis (OA). However, the magnitude of the response to leptin treatment varies greatly between chondrocytes from different donor patients. In the present study, we investigated the regulatory role of suppressor of cytokine signaling-3 (SOCS-3) in the leptin-induced responses in OA cartilage. METHODS: Cartilage and synovial fluid samples from 97 patients with OA undergoing knee replacement surgery were collected. Cartilage samples were cultured with leptin (10 μg/ml), and the levels of proinflammatory and catabolic factors in synovial fluid and in the cartilage culture media, and SOCS-3 expression in the cartilage were measured. The role of SOCS-3 in leptin signaling was further studied in H4 murine chondrocytes by downregulating SOCS-3 with siRNA. RESULTS: Leptin-induced expression of matrix metalloproteinases MMP-1, MMP-3, MMP-13, interleukin-6 (IL-6), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were higher in the cartilage samples with low SOCS-3 expression. Accordingly, downregulation of SOCS-3 by siRNA in H4 chondrocytes led to enhanced leptin-induced expression of MMP-3, MMP-13, IL-6 and iNOS. Synovial fluid leptin was associated positively, and cartilage SOCS-3 negatively with synovial fluid levels of MMPs in a multivariate model in obese (body mass index (BMI) >30 kg/m2) but not in non-obese (BMI <30 kg/m2) patients. CONCLUSIONS: Our results show, for the first time, that SOCS-3 regulates leptin-induced responses in cartilage, and could thus be a future drug target in the treatment or prevention of OA, especially in obese patientsBioMed Central open acces

An analytical model for computing the sound power of an unbraced irregular-shaped plate of variable thickness

Abstract An irregular-shaped plate with dimensions identical to a guitar soundboard is chosen for this study. It is well known that the classical guitar soundboard is a major contributor to acoustic radiation at high frequencies when compared to the bridge and sound hole. This paper focuses on using an analytical model to compute the sound power of an unbraced irregular-shaped plate of variable thickness up to frequencies of 5 kHz. The analytical model is an equivalent thin rectangular plate of variable thickness. Sound power of an irregular-shaped plate of variable thickness and with dimensions of an unbraced Torres’ soundboard is determined from computer analysis using ANSYS. The number of acoustic elements used in ANSYS for accurate simulation is six elements per wavelength. Here we show that the analytical model can be used to compute sound power of an unbraced irregular-shaped plate of variable thickness

Pharmacokinetic Modelling of Efavirenz, Atazanavir, Lamivudine and Tenofovir in the Female Genital Tract of HIV-Infected Pre-Menopausal Women

BACKGROUND AND OBJECTIVES: A previously published study of antiretroviral pharmacokinetics in the female genital tract of HIV-infected women demonstrated differing degrees of female genital tract penetration among antiretrovirals. These blood plasma (BP) and cervicovaginal fluid (CVF) data were co-modelled for four antiretrovirals with varying CVF exposures. METHODS: Six paired BP and CVF samples were collected over 24 h, and antiretroviral concentrations determined using validated liquid chromatography (LC) with UV detection or LC-mass spectrometry analytical methods. For each antiretroviral, a BP model was fit using Bayesian estimation (ADAPT5), followed by addition of a CVF model. The final model was chosen based on graphical and statistical output, and then non-linear mixed-effects modelling using S-ADAPT was performed. Population mean parameters and their variability are reported. Model-predicated area under the concentration-time curve during the dosing interval (AUC(τ)) and exposure ratios of CVF AUC(τ):BP AUC(τ) were calculated for each drug. RESULTS: The base model uses first-order absorption with a lag time, a two-compartment model, and a series of transit compartments that transfer the drug from BP to CVF. Protein-unbound drug transfers into CVF for efavirenz and atazanavir; total drug transfers for lamivudine and tenofovir. CVF follows a one-compartment model for efavirenz and atazanavir, and a two-compartment model for lamivudine and tenofovir. As expected, inter-individual variability was high. Model-predicted CVF AUC(τ):BP AUC(τ) ratios are consistent with published results. CONCLUSIONS: This is the first pharmacokinetic modelling of antiretroviral disposition in BP and CVF. These models will be further refined with tissue data, and used in clinical trials simulations to inform future studies of HIV pre-exposure prophylaxis in women

Fabrication of microfluidic channel utilizing silicone rubber with vacuum casting

10.1007/s00542-008-0640-1Microsystem Technologies1481125-113

Regional price levels and the agglomeration wage differential in western Germany

C15, J31, R23,

Clinical Pharmacokinetic, Pharmacodynamic and Drug-Interaction Profile of the Integrase Inhibitor Dolutegravir

Dolutegravir is a second generation integrase strand transfer inhibitor (INSTI) currently under review by the US FDA for marketing approval. Dolutegravir’s in vitro, protein adjusted 90% inhibitory concentration (IC(90)) for wild-type virus is 0.064 μg/ml, and it retains in vitro anti-HIV 1 activity across a broad range of viral phenotypes known to confer resistance to the currently marketed INSTIs, raltegravir and elvitegravir. Dolutegravir has a half-life (t(½)) of 13 to 14 hours and maintains concentrations over the in vitro, protein adjusted IC(90) for more than 30 hours following a single dose. Additionally, dolutegravir has comparatively low intersubject variability compared to raltegravir and elvitegravir. A plasma exposure-response relationship has been well described, with antiviral activity strongly correlating to trough concentration (C(trough)) values. Phase III trials have assessed the antiviral activity of dolutegravir compared with efavirenz and raltegravir in antiretroviral (ARV)-naïve patients and found dolutegravir to achieve more rapid and sustained virologic suppression in both instances. Additionally, studies of dolutegravir activity in patients with known INSTI-resistant mutations have been favorable, indicating that dolutegravir retains activity in a variety of INSTI resistant phenotypes. Much like currently marketed INSTIs, dolutegravir is very well tolerated. Because dolutegravir inhibits the renal transporter, organic cation transporter (OCT) 2, reduced tubular secretion of creatinine leads to non-progressive increases in serum creatinine. These serum creatinine increases have not been associated with decreased glomerular filtration rate or progressive renal impairment. Dolutegravir’s major and minor metabolic pathways are UDP glucuronosyltransferase (UGT)1A1 and cytochrome (CYP)3A4, respectively, and it neither induces nor inhibits CYP isozymes. Thus dolutegravir has a modest drug interaction profile. However, antacids significantly decrease dolutegravir plasma exposure and should be separated by 2 hours before, or 6 hours after, a dolutegravir dose. In summary, dolutegravir is the first of the second generation INSTIs, which exhibits a predictable pharmacokinetic profile and a well-defined exposure-response relationship. Dolutegravir retains activity despite the presence of some class resistant mutations and achieves rapid and sustained virologic suppression in ARV-naïve and -experienced patients. Clinically dolutegravir is poised to become a commonly used component of antiretroviral regimens

Pharmacokinetics of Antiretrovirals in Genital Secretions and Anatomic Sites of HIV Transmission: Implications for HIV Prevention

The incidence of HIV remains alarmingly high in many parts of the world. Prophylactic use of antiretrovirals, capable of concentrating in the anatomical sites of transmission, may reduce the risk of infection after an unprotected sexual exposure. To date, orally and topically administered antiretrovirals have exhibited variable success in preventing HIV transmission in large-scale clinical trials. Antiretroviral mucosal pharmacokinetics may help explain the outcomes of these investigations. Penetration and accumulation of antiretrovirals into sites of transmission can influence dosing strategies and pre-exposure prophylaxis clinical trial design. Antiretroviral tissue distribution varies widely within and between drug classes, attributed in part to their physicochemical properties and tissue-specific drug transporter expression. Nucleoside (-tide) reverse transcriptase inhibitors, the CCR5 antagonist maraviroc, and the integrase inhibitor raltegravir demonstrate the highest penetration into the male and female reproductive tracts and colorectal tissue relative to blood. This review will describe antiretroviral exposure in anatomic sites of transmission, and place these findings in context with the prevention of HIV and the efficacy of pre-exposure prophylactic strategies