1,957 research outputs found
Probing weakly-bound molecules with nonresonant light
We show that weakly-bound molecules can be probed by "shaking" in a pulsed
nonresonant laser field. The field introduces a centrifugal term which expels
the highest vibrational level from the potential that binds it. Our numerical
simulations applied to the Rb and KRb Feshbach molecules indicate that
shaking by feasible laser pulses can be used to accurately recover the square
of the vibrational wavefunction and, by inversion, also the long-range part of
the molecular potential.Comment: revised version, 4 pages, 4 figure
Representation theory of wreath products of finite groups.
This is an exposition on the representation theory of wreath products of finite groups, with many examples worked out
Finite Gel'fand pairs and their applications to Probability and Statistics
We present a general introduction to finite Gel’fand pairs and their associated spherical functions
yielding different characterizations, examine a few explicit examples, and, for each of these examples,
analyze the corresponding probabilistic problem, which will then be solved by applying the general results
and the machinery developed for a particular Gel’fand pair
Resistance to novel drug classes
Understanding the mechanisms that underlie resistance
development to novel drugs is essential to a better clinical management of
resistant viruses and to prevent further resistance development and spread.
RECENT FINDINGS: Integrase inhibitors and CCR5 antagonists are the more recent
antiretroviral classes developed. The HIV-1 integrase, responsible for the
chromosomal integration of the newly synthesized double-stranded viral DNA into
the host genomic DNA, represents a new and important target; and two integrase
inhibitors (INIs), raltegravir and elvitegravir, have been shown promising
results in clinical trials. Viral entry is also an attractive step for the
development of new drugs against HIV variants resistant to current antiretroviral
drugs, and two CCR5 antagonists have been designed to inhibit HIV-1 binding to R5
co-receptor and are under clinical investigation.
SUMMARY: Drug resistance to INIs occurs through the selection of mutations within
HIV integrase. The kinetic of selection seems rapid and one mutation alone is
able to confer resistance to integrase inhibitor, suggesting that this class of
drug has a low genetic barrier. Two ways could explain the failure of the CCR5
antagonist class: a rapid outgrowth of pre-existing archived X4 virus or the
selection of a resistance to CCR5 antagonists through amino acid changes in V
Maxwell equations in matrix form, squaring procedure, separating the variables, and structure of electromagnetic solutions
The Riemann -- Silberstein -- Majorana -- Oppenheimer approach to the Maxwell
electrodynamics in vacuum is investigated within the matrix formalism. The
matrix form of electrodynamics includes three real 4 \times 4 matrices. Within
the squaring procedure we construct four formal solutions of the Maxwell
equations on the base of scalar Klein -- Fock -- Gordon solutions. The problem
of separating physical electromagnetic waves in the linear space
\lambda_{0}\Psi^{0}+\lambda_{1}\Psi^{1}+\lambda_{2}\Psi^{2}+ lambda_{3}\Psi^{3}
is investigated, several particular cases, plane waves and cylindrical waves,
are considered in detail.Comment: 26 pages 16 International Seminar NCPC, May 19-22, 2009, Minsk,
Belaru
Induced representations and Mackey theory
This is an exposition on Mackey theory for induced representations of finite group
Comparative antiviral activity of integrase inhibitors in human monocyte-derived macrophages and lymphocytes
The activity of raltegravir and 4 other integrase inhibitors (MK-2048, L870,810,
IN2, and IN5) was investigated in primary human macrophages, PBMC and
C8166-lymphocytic T cells, in order to determine their relative potency and
efficacy in different cellular systems of HIV infection. Raltegravir showed
better protective efficacy in all cell types; MK-2048, L870,810 and IN5 showed a
potent anti-HIV-1 activity in macrophages, while in lymphocytes only MK-2048 and
L870,810 showed an inhibitory effect comparable to raltegravir. IN2 was a poorly
effective anti-HIV-1 compound in all cellular systems. All effective integrase
inhibitors exhibited a potent antiviral activity against both X4 and R5 HIV-1
strains. In general, raltegravir, MK-2048, L870,810 and IN5 showed anti HIV
activity similar or slightly higher in macrophages compared to PBMC and C8166 T
cells: for MK-2048, the EC(50) was 0.4, 0.9, 11.5nM in macrophages, in PBMCs and
T cells, respectively; for L870,810, the EC(50) was 1.5, 14.3, and 10.6nM,
respectively; for IN5 the EC(50) was 0.5, 13.7, and 5.7nM, respectively
Erenumab in chronic migraine: Patient-reported outcomes in a randomized double-blind study.
OBJECTIVE: To determine the effect of erenumab, a human monoclonal antibody targeting the calcitonin gene-related peptide receptor, on health-related quality of life (HRQoL), headache impact, and disability in patients with chronic migraine (CM).
METHODS: In this double-blind, placebo-controlled study, 667 adults with CM were randomized (3:2:2) to placebo or erenumab (70 or 140 mg monthly). Exploratory endpoints included migraine-specific HRQoL (Migraine-Specific Quality-of-Life Questionnaire [MSQ]), headache impact (Headache Impact Test-6 [HIT-6]), migraine-related disability (Migraine Disability Assessment [MIDAS] test), and pain interference (Patient-Reported Outcomes Measurement Information System [PROMIS] Pain Interference Scale short form 6b).
RESULTS: Improvements were observed for all endpoints in both erenumab groups at month 3, with greater changes relative to placebo observed at month 1 for many outcomes. All 3 MSQ domains were improved from baseline with treatment differences for both doses exceeding minimally important differences established for MSQ-role function-restrictive (≥3.2) and MSQ-emotional functioning (≥7.5) and for MSQ-role function-preventive (≥4.5) for erenumab 140 mg. Changes from baseline in HIT-6 scores at month 3 were -5.6 for both doses vs -3.1 for placebo. MIDAS scores at month 3 improved by -19.4 days for 70 mg and -19.8 days for 140 mg vs -7.5 days for placebo. Individual-level minimally important difference was achieved by larger proportions of erenumab-treated participants than placebo for all MSQ domains and HIT-6. Lower proportions of erenumab-treated participants had MIDAS scores of severe (≥21) or very severe (≥41) or PROMIS scores ≥60 at month 3.
CONCLUSIONS: Erenumab-treated patients with CM experienced clinically relevant improvements across a broad range of patient-reported outcomes.
CLINICALTRIALSGOV IDENTIFIER: NCT02066415.
CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that for patients with CM, erenumab treatment improves HRQoL, headache impact, and disability
Computational analysis of Human Immunodeficiency Virus (HIV) Type-1 reverse transcriptase crystallographic models based on significant conserved residues found in Highly Active Antiretroviral Therapy (HAART)-treated patients.
Reverse transcription of the viral single-stranded (+) RNA genome into double-stranded DNA is an essential step in the human immunodeficiency virus' (HIV) life-cycle. Although several viral proteins are involved in the regulation and/or efficiency of reverse transcription, the process of retroviral DNA synthesis is entirely dependent on the enzymatic activities of the retroviral reverse transcriptase enzyme (RT). Due to its crucial role in the HIV life-cycle, RT is a primary target for anti-HIV drug development. Nonetheless, drug resistance is the major problem affecting the clinical efficacy of antiretroviral agents. Incomplete pharmacological pressure represents the logical cause and not the consequence of different mutation pathways in RT associated with approved inhibitors resistance.
In this review we have analyzed RT Protein Data Bank (PDB) models using our innovative computational approach “GRID Based Pharmacophore Model” (GBPM). This method was applied to clinically relevant RT conserved residues found in a large cohort of HAART treated patients. The PDB entries have been selected among the unbound and the complexed models with DNA and/or inhibitors. Such an approach has revealed itself useful to highlight the mutation effects in the drug-RT recognition as well as in the heterodimer stabilization of the enzyme. Most of the clinical and biochemical evidences already reported in the literature have been rationalized at molecular level via the GBPM computational approach. A definite future application of this method will be the identification of conserved regions of critical macromolecules, such as the HIV-1 RT, to be targeted for the development of innovative therapeutic agents
Selected amino acid changes in HIV-1 subtype-C gp41 are associated with specific gp120(V3) signatures in the regulation of co-receptor usage
The majority of studies have characterized the tropism of HIV-1 subtype-B isolates, but little is known about the determinants of tropism in other subtypes. So, the goal of the present study was to genetically characterize the envelope of viral proteins in terms of co-receptor usage by analyzing 356 full-length env sequences derived from HIV-1 subtype-C infected individuals. The co-receptor usage of V3 sequences was inferred by using the Geno2Pheno and PSSM algorithms, and also analyzed to the "11/25 rule". All reported env sequences were also analyzed with regard to N-linked glycosylation sites, net charge and hydrophilicity, as well as the binomial correlation phi coefficient to assess covariation among gp120(V3) and gp41 signatures and the average linkage hierarchical agglomerative clustering were also performed. Among env sequences present in Los Alamos Database, 255 and 101 sequences predicted as CCR5 and CXCR4 were selected, respectively. The classical V3 signatures at positions 11 and 25, and other specific V3 and gp41 amino acid changes were found statistically associated with different co-receptor usage. Furthermore, several statistically significant associations between V3 and gp41 signatures were also observed. The dendrogram topology showed a cluster associated with CCR5-usage composed by five gp41 mutated positions, A22V, R133M, E136G, N140L, and N166Q that clustered with T2V(V3) and G24T(V3) (bootstrap=1). Conversely, a heterogeneous cluster with CXCR4-usage, involving S11GR(V3), 13-14insIG/LG(V3), P16RQ(V3), Q18KR(V3), F20ILV(V3), D25KRQ(V3), Q32KR(V3) along with A30T(gp41), S107N(gp41), D148E(gp41), A189S(gp41) was identified (bootstrap=0.86). Our results show that as observed for HIV-1 subtype-B, also in subtype-C specific and different gp41 and gp120V3 amino acid changes are associated individually or together with CXCR4 and/or CCR5 usage. These findings strengthen previous observations that determinants of tropism may also reside in the gp41 protein
- …