Search results for "Organophosphonates"
showing 10 items of 33 documents
Analytical insight into degradation processes of aminopolyphosphonates as potential factors that induce cyanobacterial blooms
2017
Aminopolyphosphonates (AAPs) are commonly used industrial complexones of metal ions, which upon the action of biotic and abiotic factors undergo a breakdown and release their substructures. Despite the low toxicity of AAPs towards vertebrates, products of their transformations, especially those that contain phosphorus and nitrogen, can affect algal communities. To verify whether such chemical entities are present in water ecosystems, much effort has been made in developing fast, inexpensive, and reliable methods for analyzing phosphonates. However, unfortunately, the methods described thus far require time-consuming sample pretreatment and offer relatively high values of the limit of detect…
Lamivudine/Adefovir Treatment Increases the Rate of Spontaneous Mutation of Hepatitis B Virus in Patients.
2016
The high levels of genetic diversity shown by hepatitis B virus (HBV) are commonly attributed to the low fidelity of its polymerase. However, the rate of spontaneous mutation of human HBV in vivo is currently unknown. Here, based on the evolutionary principle that the population frequency of lethal mutations equals the rate at which they are produced, we have estimated the mutation rate of HBV in vivo by scoring premature stop codons in 621 publicly available, full-length, molecular clone sequences derived from patients. This yielded an estimate of 8.7 × 10-5 spontaneous mutations per nucleotide per cell infection in untreated patients, which should be taken as an upper limit estimate becau…
Identification of the Privileged Position in the Imidazo[1,2-a]pyridine Ring of Phosphonocarboxylates for Development of Rab Geranylgeranyl Transfera…
2017
Members of the Rab GTPase family are master regulators of vesicle trafficking. When disregulated, they are associated with a number of pathological states. The inhibition of RGGT, an enzyme responsible for post-translational geranylgeranylation of Rab GTPases represents one way to control the activity of these proteins. Because the number of molecules modulating RGGT is limited, we combined molecular modeling with biological assays to ascertain how modifications of phosphonocarboxylates, the first reported RGGT inhibitors, rationally improve understanding of their structure-activity relationship. We have identified the privileged position in the core scaffold of the imidazo[1,2-a]pyridine r…
Management and treatment of chronic hepatitis B virus infection in HIV positive and negative patients: The EPIB 2008 study
2010
To compare the management and the virological and serological efficacy of treatments for chronic hepatitis B (CHB) in HIV positive and negative patients.Two hundred and forty-six HIV positive and 205 HIV negative consecutive patients with past or present CHB, seen in October 2008 in participating departments, were included in a multicenter study. All the data were retrospectively collected from the first visit to October 2008 through a standardized questionnaire.Compared to HIV negative patients, HIV positive patients more often presented positive HBeAg (46.4% vs. 32.8%, p=0.01), HBV genotype A (54.8% vs. 17.1%, p0.0001), co-infection with HCV (12.4% vs. 5.9%, p=0.0002) or HDV (12.6% vs. 2.…
Long-Term Efficacy of Tenofovir Monotherapy for Hepatitis B Virus-Monoinfected Patients After Failure of Nucleoside/Nucleotide Analogues
2010
Tenofovir disoproxil fumarate (TDF) has demonstrated high antiviral efficacy in treatment-naive patients with chronic hepatitis B virus (HBV) infection but experience in nucleoside/nucleotide analogue (NA)-experienced patients is limited. In this retrospective multicenter study we therefore assessed the long-term efficacy of TDF monotherapy in patients with prior failure or resistance to different NA treatments. Criteria for inclusion were HBV DNA levels >4.0 log(10) copies/mL at the start and a minimum, period of TDF therapy for at least 6 months. In all, 131 patients (mean age 42 +/- 12 years, 95 male, 65% hepatitis B e antigen [HBeAg]-positive) were eligible. Pretreatment consisted of…
Current practice of chronic hepatitis B treatment in Southern Italy
2012
Abstract Background Treatment choice for chronic HBV infection is a continuously evolving issue, with a wide range of options. We aimed to evaluate the current practice of HBV therapies in the real world in Southern Italy. Methods A prospective study enrolling over a six month period (February–July 2010) all consecutive HBsAg positive subjects, never previously treated, referred to 16 liver units in two Southern Italy regions (Calabria and Sicily). Results Out of 247 subjects evaluated, 116 (46.9%) had HBV-DNA undetectable or lower than 2000 UI/ml. There were 108 (43.7%) inactive carriers, 103 (41.7%) chronic hepatitis, and 36 (14.6%) liver cirrhosis. Antiviral treatment was planned in 94 (…
Role of a 48-week pegylated interferon therapy in hepatitis B e antigen positive HIV-co-infected patients on cART including tenofovir: EMVIPEG study.
2014
In hepatitis B e antigen (HBeAg) positive-HIV co-infected patients treated with combined antiretroviral therapy (cART), including tenofovir disoproxil fumarate (TDF), the rate of HBe seroconversion remains low. Whether adding pegylated interferon alfa (PegIFN) could increase the likelihood of HBeAg loss and HBe seroconversion has not been assessed.A 48-week PegIFN therapy was added to HBeAg positive-HIV co-infected patients on TDF and emtricitabine, or lamivudine for at least 6 months. The primary endpoint was HBV sustained response: HBe seroconversion with undetectable HBV DNA levels 24 weeks after completing PegIFN therapy (W72).Fifty-one patients (49 men, median age 46 years, range: 32-6…
Quantification of hydrolysis of toxic organophosphates and organophosphonates by diisopropyl fluorophosphatase from Loligo vulgaris by in situ Fourie…
2008
Abstract The enzyme diisopropyl fluorophosphatase (DFPase) from the squid Loligo vulgaris effectively catalyzes the hydrolysis of diisopropyl fluorophosphate (DFP) and a number of organophosphorus nerve agents, including sarin, soman, cyclosarin, and tabun. Up to now, the determination of kinetic data has been achieved by techniques such as pH-stat titration, ion-selective electrodes, and fluorogenic substrate analogs. We report a new assaying method using in situ Fourier transform infrared (FTIR) spectroscopy with attenuated total reflection (ATR) for the real-time determination of reaction rates. The method employs changes in the P–O–R stretching vibration of DFP and nerve agent substrate…
Functionalized Polystyrene Nanoparticles Trigger Human Dendritic Cell Maturation Resulting in Enhanced CD4+T Cell Activation
2012
Nanoparticles (NP) represent a promising tool for biomedical applications. Here, sulfonate- and phosphonate-functionalized polystyrene NP are analyzed for their interaction with human monocyte-derived dendritic cells (DC). Immature dendritic cells (iDC) display a higher time- and dose-dependent uptake of functionalized polystyrene NP compared to mature dendritic cells (mDC). Notably, NP induce an enhanced maturation of iDC but not of mDC (upregulation of stimulatory molecules and cytokines). NP-triggered maturation results in a significantly enhanced T cell stimulatory capacity (increased CD4(+) T cell proliferation and IFN-γ production), indicating a shift to a pronounced Th1 response. Imm…
Structure-Dependent Dissolution and Restructuring of Calcite Surfaces by Organophosphonates
2017
Organophosphonates are well-known to strongly interact with the surfaces of various minerals, such as brucite, gypsum, and barite. In this work, we study the influence of six systematically varied organophosphonate molecules (tetraphosphonates and diphosphonates) on the dissolution process of the (10.4) surface of calcite. In order to pursue a systematic study, we have selected organophosphonates that exhibit similar structural features, but also systematic architectural differences. The effect of this class of additives on the dissolution process of the calcite (10.4) surface is evaluated using in situ dynamic atomic force microscopy. For all of the six organophosphonate derivatives, we ob…