97 research outputs found

    Polarization sensitive optical frequency domain imaging system for endobronchial imaging

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    A polarization sensitive endoscopic optical frequency domain imaging (PS-OFDI) system with a motorized distal scanning catheter is demonstrated. It employs a passive polarization delay unit to multiplex two orthogonal probing polarization states in depth, and a polarization diverse detection unit to detect interference signal in two orthogonal polarization channels. Per depth location four electro-magnetic field components are measured that can be represented in a complex 2Ă—2 field matrix. A Jones matrix of the sample is derived and the sample birefringence is extracted by eigenvalue decomposition. The condition of balanced detection and the polarization mode dispersion are quantified. A complex field averaging method based on the alignment of randomly pointing field phasors is developed to reduce speckle noise. The variation of the polarization states incident on the tissue due to the circular scanning and catheter sheath birefringence is investigated. With this system we demonstrated imaging of ex vivo chicken muscle, in vivo pig lung and ex vivo human lung specimens

    Pyridazinediones and amino acid receptors: theoretical studies, design, synthesis, and evaluation of novel analogues

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    http://www.pharmacol.usyd.edu.au/thesis This thesis is primarily concerned with a class of chemical compounds known as pyridazinediones, being 6-membered aromatic rings containing two adjacent nitrogen atoms (pyridazine), doubly substituted with oxygen. In particular, the work focuses on pyridazine-3,6-diones, derivatives of maleic hydrazide (1). Understanding of the chemistry of these compounds is extended, using theoretical and synthetic techniques. This thesis is also concerned with two very important classes of receptors which bind amino acids in the brain: firstly, the inhibitory GABA receptor, which binds g-aminobutyric acid (GABA) (2) in vivo, and for which muscimol (3) is an agonist of the GABAA subclass; secondly, Excitatory Amino Acid (EAA) receptors, which bind glutamate (4) in vivo, and in particular the AMPA subclass, for which (S)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) (5) is an agonist. The connection between pyridazinediones and amino acid receptors is the design, synthesis, and evaluation of structures based on pyridazinediones as potential GABA and EAA receptor ligands. Techniques of theoretical chemistry, molecular modelling, synthetic chemistry, and in vitro pharmacology are used to explore pyridazine-3,6-dione derivatives as ligands

    Analysis of the antigen- and mitogen-induced differentiation of B lymphocytes from asymptomatic human immunodeficiency virus-seropositive male homosexuals. Discrepancy between T cell-dependent and T cell-independent activation.

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    Five asymptomatic human immunodeficiency virus (HIV)-seropositive ; male homosexuals were immunized with the recall antigens tetanus toxoid (TT) and the three types of poliovirus present in diphtheria, tetanus, and polio vaccine. Four weeks after immunization, the in vivo response to booster immunization, the in vitro pokeweed mitogen (PWM)-induced IgG secretion, and the in vitro T cell-dependent and T cell-independent antigen-induced antibody response were assayed. Increase in serum antibody titer to TT and polioviru

    The steady-state pharmacokinetics of efavirenz and nevirapine when used in combination in human immunodeficiency virus type 1-infected persons

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    The steady-state pharmacokinetics of efavirenz and nevirapine, when used in combination to treat human immunodeficiency virus type 1 (HIV-1)-infected subjects, were investigated. HIV-1-infected persons who had used efavirenz (600 mg once daily) for > or =2 weeks were eligible for study inclusion. The plasma pharmacokinetics of efavirenz were determined over 24 h. Subsequently, nevirapine (400 mg once daily) was added to the regimen. After 4 weeks, the pharmacokinetics of efavirenz and nevirapine were assessed over 24 h. The differences between the pharmacokinetic parameters of efavirenz with and without nevirapine were analyzed, and the pharmacokinetics of nevirapine were compared with those in historical control patients. The exposure to efavirenz when combined with nevirapine was significantly decreased by 22% (area under the plasma concentration vs. time curve), 36% (minimum plasma concentration), and 17% (maximum plasma concentration). Nevirapine pharmacokinetics appear to be unaffected by coadministration of efavirenz, compared with data from historical control patient

    No Treatment versus 24 or 60 Weeks of Antiretroviral Treatment during Primary HIV Infection: The Randomized Primo-SHM Trial

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    Background: The objective of this study was to assess the benefit of temporary combination antiretroviral therapy (cART) during primary HIV infection (PHI). Methods and Findings: Adult patients with laboratory evidence of PHI were recruited in 13 HIV treatment centers in the Netherlands and randomly assigned to receive no treatment or 24 or 60 wk of cART (allocation in a 1:1:1 ratio); if therapy was clinically indicated, participants were randomized over the two treatment arms (allocation in a 1:1 ratio). Primary end points were (1) viral set point, defined as the plasma viral load 36 wk after randomization in the no treatment arm and 36 wk after tr Conclusions: In this trial, temporary cART during PHI was found to transiently lower the viral set point and defer the restart of cART during chronic HIV infection

    Has the Rate of CD4 Cell Count Decline before Initiation of Antiretroviral Therapy Changed over the Course of the Dutch HIV Epidemic among MSM?

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    Introduction:Studies suggest that the HIV-1 epidemic in the Netherlands may have become more virulent, leading to faster disease progression if untreated. Analysis of CD4 cell count decline before antiretroviral therapy (ART) initiation, a surrogate marker for disease progression, may be hampered by informative censoring as ART initiation is more likely with a steeper CD4 cell count decline.Methods:Development of CD4 cell count from 9 to 48 months after seroconversion was analyzed using a mixed-effects model and 2 models that jointly modeled CD4 cell counts and time to censoring event (start ART

    Influence of Conversion and Anastomotic Leakage on Survival in Rectal Cancer Surgery; Retrospective Cross-sectional Study

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