How and when does an anticancer drug leave its binding site?

Obtaining atomistic resolution of drug unbinding from a protein is a much sought-after experimental and computational challenge. We report the unbinding dynamics of the anticancer drug dasatinib from c-Src kinase in full atomistic resolution using enhanced sampling molecular dynamics simulations. We obtain multiple unbinding trajectories and determine a residence time in agreement with experiments. We observe coupled protein-water movement through multiple metastable intermediates. The water molecules form a hydrogen bond bridge, elongating a specific, evolutionarily preserved salt bridge and enabling conformation changes essential to ligand unbinding. This water insertion in the salt bridge acts as a molecular switch that controls unbinding. Our findings provide a mechanistic rationale for why it might be difficult to engineer drugs targeting certain specific c-Src kinase conformations to have longer residence times

Finite β\beta Effects on Short Wavelength Ion Temperature Gradient Modes

The electromagnetic effect is studied on the short wavelength branch of the ion temperature gradient mode in the linear regime for the first time using a global gyrokinetic model. The short wavelength ion temperature gradient mode growth rate is found to be reduced in the presence of electromagnetic perturbations at finite plasma $\beta$. The effect on real frequency is found to be weak. The threshold value of $\eta_i$ is found to increase for the mode as the magnitude of $\beta$ is increased. The global mode structure of the short wavelength branch of the ion temperature gradient mode is compared with the conventional branch. The magnetic character of the mode, measured as the ratio of mode average square values of electromagnetic potential to electrostatic potential, is found to increase with increasing values of the plasma $\beta$. The mixing length estimate for flux shows that the maximum contribution still comes from the long wavelengths modes. The magnitude of the flux decreases with increasing $\beta$.Comment: 23 pages,23 figure

Differential scanning calorimetry and wide-angle X-ray scattering studies of bread staling

Wide angle X-ray scattering (WAXS) was used to follow the development of crystal size and strain during the staling of bread containing different additives. In this it was observed that one can classify the good anti-staling additives as gelatin, propylene glycol, maltodextrin and anti-staling enzyme corresponding to the order of increasing crystal size for a particular Bragg reflection in all the samples and correlate using DSC (differential scanning calorimetry) studies of all the bread compositions containing different additives. (C) 1998 John Wiley & Sons, Inc

Pembrolizumab in combination with pomalidomide and low-dose dexamethasone in refractory or relapsed and refractory multiple myeloma (rrMM): Randomized, phase 3 KEYNOTE-183 study

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The fbpA/sapM Double Knock Out Strain of Mycobacterium tuberculosis Is Highly Attenuated and Immunogenic in Macrophages

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), is the leading cause of death due to bacterial infections in mankind, and BCG, an attenuated strain of Mycobacterium bovis, is an approved vaccine. BCG sequesters in immature phagosomes of antigen presenting cells (APCs), which do not fuse with lysosomes, leading to decreased antigen processing and reduced Th1 responses. However, an Mtb derived ΔfbpA attenuated mutant underwent limited phagosome maturation, enhanced immunogenicity and was as effective as BCG in protecting mice against TB. To facilitate phagosome maturation of ΔfbpA, we disrupted an additional gene sapM, which encodes for an acid phosphatase. Compared to the wild type Mtb, the ΔfbpAΔsapM (double knock out; DKO) strain was attenuated for growth in mouse macrophages and PMA activated human THP1 macrophages. Attenuation correlated with increased oxidants in macrophages in response to DKO infection and enhanced labeling of lysosomal markers (CD63 and rab7) on DKO phagosomes. An in vitro Antigen 85B peptide presentation assay was used to determine antigen presentation to T cells by APCs infected with DKO or other mycobacterial strains. This revealed that DKO infected APCs showed the strongest ability to present Ag85B to T cells (>2500 pgs/mL in 4 hrs) as compared to APCs infected with wild type Mtb or ΔfbpA or ΔsapM strain (<1000 pgs/mL in 4 hrs), indicating that DKO strain has enhanced immunogenicity than other strains. The ability of DKO to undergo lysosomal fusion and vacuolar acidification correlated with antigen presentation since bafilomycin, that inhibits acidification in APCs, reduced antigen presentation. Finally, the DKO vaccine elicited a better Th1 response in mice after subcutaneous vaccination than either ΔfbpA or ΔsapM. Since ΔfbpA has been used in mice as a candidate vaccine and the DKO (ΔfbpAΔsapM) mutant is more immunogenic than ΔfbpA, we propose the DKO is a potential anti-tuberculosis vaccine

Beta2-adrenoceptor agonists for dysmenorrhoea

Background:Dysmenorrhoea is a common gynaecological complaint that can affect as many as 50% of premenopausal women, 10% of whom suffer severely enough to be rendered incapacitated for one to three days during each menstrual cycle. Primary dysmenorrhoea is where women suffer from menstrual pain but lack any pathology in their pelvic anatomy. Beta2-adrenoceptor agonists have been used in the treatment of women with primary dysmenorrhoea but their effects are unclear.Objectives:To determine the effectiveness and safety of beta2-adrenoceptor agonists in the treatment of primary dysmenorrhoea. Search methods: We searched the Cochrane Menstrual Disorders and Subfertility Group Specialised Register, CENTRAL (The Cochrane Library 2011, Issue 8), MEDLINE, EMBASE, PsycINFO and the EBM Reviews databases. The last search was on 22 August 2011.Selection criteriaRandomised controlled trials comparing beta2-adrenoceptor agonists with placebo or no treatment, each other or any other conventional treatment in women of reproductive age with primary dysmenorrhoea. Data collection and analysisTwo review authors independently assessed trial quality and extracted the data.Main results:Five trials involving 187 women with an age range of 15 to 40 years were included. Oral isoxsuprine was compared with placebo in two trials, terbutaline oral spray, ritodrine chloride and oral hydroxyphenyl-orciprenalin were compared with placebo in a further three trials. Clinical diversity in the studies in terms of the interventions being evaluated, assessments at different time points and the use of different assessment tools mitigated against pooling of outcome data across studies in order to provide a summary estimate of effect for any of the comparisons. Only one study, with unclear risk of bias, reported pain relief with a combination of isoxsuprine, acetaminophen and caffeine. None of the other studies reported any significant clinical difference in effectiveness between the intervention and placebo. Adverse effects were reported with all of these medications in up to a quarter of the total number of participants. They included nausea, vomiting, dizziness, quivering, tremor and palpitations.Authors\u27 conclusions:The evidence presented in this review was based on a few relatively small-sized studies that were categorised to have unclear to high risk of bias, which does not allow confident decision-making at present about the use of beta2-adrenoceptor agonists for dysmenorrhoea. The benefits as reported in one study should be balanced against the wide array of unacceptable side effects documented with this class of medication. We have emphasised the lack of precision and limitations in the reported data where appropriate

Angiotensin II stimulates superoxide production by nitric oxide synthase in thick ascending limbs

Angiotensin II (Ang II) causes nitric oxide synthase (NOS) to become a source of superoxide (O2 (-)) via a protein kinase C (PKC)-dependent process in endothelial cells. Ang II stimulates both NO and O2 (-) production in thick ascending limbs. We hypothesized that Ang II causes O2 (-) production by NOS in thick ascending limbs via a PKC-dependent mechanism. NO production was measured in isolated rat thick ascending limbs using DAF-FM, whereas O2 (-) was measured in thick ascending limb suspensions using the lucigenin assay. Consistent stimulation of NO was observed with 1 nmol/L Ang II (P \u3c 0.001; n = 9). This concentration of Ang II-stimulated O2 (-) production by 50% (1.77 ± 0.26 vs. 2.62 ± 0.36 relative lights units (RLU)/s/μg protein; P \u3c 0.04; n = 5). In the presence of the NOS inhibitor L-NAME, Ang II-stimulated O2 (-) decreased from 2.02 ± 0.29 to 1.10 ± 0.11 RLU/s/μg protein (P \u3c 0.01; n = 8). L-arginine alone did not change Ang II-stimulated O2 (-) (2.34 ± 0.22 vs. 2.29 ± 0.29 RLU/s/μg protein; n = 5). In the presence of Ang II plus the PKC α/β1 inhibitor Gö 6976, L-NAME had no effect on O2 (-) production (0.78 ± 0.23 vs. 0.62 ± 0.11 RLU/s/μg protein; n = 7). In the presence of Ang II plus apocynin, a NADPH oxidase inhibitor, L-NAME did not change O2 (-) (0.59 ± 0.04 vs. 0.61 ± ×0.08 RLU/s/μg protein; n = 5). We conclude that: (1) Ang II causes NOS to produce O2 (-) in thick ascending limbs via a PKC- and NADPH oxidase-dependent process; and (2) the effect of Ang II is not due to limited substrate