bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intrapulmonary Pharmacokinetics and Pharmacodynamics of Itraconazole and 14-Hydroxyitraconazole at Steady State
Authors: Conte John E. , Golden Jeffrey A. , Kipps Juliana , McIver Marina , Zurlinden Elisabeth 
Published: September 2004

ABSTRACTWe determined the steady-state intrapulmonary pharmacokinetic and pharmacodynamic parameters of orally administered itraconazole (ITRA), 200 mg every 12 h (twice a day [b.i.d.]), on an empty stomach, for a total of 10 doses, in 26 healthy volunteers. Five subgroups each underwent standardized bronchoscopy and bronchoalveolar lavage (BAL) at 4, 8, 12, 16, and 24 h after administration of the last dose. ITRA and its main metabolite, 14-hydroxyitraconazole (OH-IT), were measured in plasma, BAL fluid, and alveolar cells (AC) using high-pressure liquid chromatography. Half-life and area under the concentration-time curves (AUC) in plasma, epithelial lining fluid (ELF), and AC were derived using noncompartmental analysis. ITRA and OH-IT maximum concentrations of drug (Cmax) (mean ± standard deviation) in plasma, ELF, and AC were 2.1 ± 0.8 and 3.3 ± 1.0, 0.5 ± 0.7 and 1.0 ± 0.9, and 5.5 ± 2.9 and 6.6 ± 3.1 μg/ml, respectively. The ITRA and OH-IT AUC for plasma, ELF, and AC were 34.4 and 60.2, 7.4 and 18.9, and 101 and 134 μg · hr/ml. The ratio of theCmaxand the MIC at which 90% of the isolates were inhibited (MIC90), the AUC/MIC90ratio, and the percent dosing interval above MIC90for ITRA and OH-IT concentrations in AC were 1.1 and 3.2, 51 and 67, and 100 and 100%, respectively. Plasma, ELF, and AC concentrations of ITRA and OH-IT declined monoexponentially with half-lives of 23.1 and 37.2, 33.2 and 48.3, and 15.7 and 45.6 h, respectively. An oral dosing regimen of ITRA at 200 mg b.i.d. results in concentrations of ITRA and OH-ITRA in AC that are significantly greater than those in plasma or ELF and intrapulmonary pharmacodynamics that are favorable for the treatment of fungal respiratory infection.
Antimicrobial Activity of Euplotin C, the Sesquiterpene Taxonomic Marker from the Marine Ciliate
Euplotes crassus
Authors: Savoia Dianella , Avanzini Claudio , Allice Tiziano , Callone Emanuela , Guella Graziano , Dini Fernando 
Published: September 2004

ABSTRACT

Strains of the marine ciliate protist
Euplotes crassus
produce exclusive terpenoids called euplotins that play an ecological role. Among these derivatives, euplotin C is the main of four secondary metabolites isolated from cultures of this protozoon and represents the sesquiterpene taxonomic marker from
E. crassus
. Because different terpenoid metabolites of plant origin showed a certain antimicrobial activity, we assessed the compound euplotin C, purified by high-pressure liquid chromatography and solubilized in two solubility enhancers, against the protozoa
Leishmania major
and
Leishmani infantum
, the fungus
Candida albicans
, and nine strains of gram-positive and gram-negative microorganisms. An activity of euplotin C against
Leishmania
promastigotes was demonstrated (50% lethal doses were 4.6 or 8.1 μg/ml depending on the agent used to solubilize the compound), while the effect was less evident on
Candida
and nearly absent on bacteria. A nonsignificant cytotoxicity (50% lethal dose, >200 μg/ml) against the J774 cell line was observed. A leishmanicidal activity was also shown by the living, euplotin-producing cells of
E. crassus
cultured together with promastigotes; this activity increased with time from 10 min to 6 h of incubation. This study provides an initial rationale for the evaluation of euplotin C and other similar natural products as alternative or possibly synergistic compounds for current antiprotozoon chemotherapeutics.
In Vitro Comparison of Topical Microbicides for Prevention of Human Immunodeficiency Virus Type 1 Transmission
Authors: Dezzutti Charlene S. , James V. Nicole , Ramos Artur , Sullivan Sharon T. , Siddig Aladin , Bush Timothy J. , Grohskopf Lisa A. , Paxton Lynn , Subbarao Shambavi , Hart Clyde E. 
Published: September 2004

ABSTRACT

A standardized protocol was used to compare cellular toxicities and anti-human immunodeficiency virus type 1 (HIV-1) activities of candidate microbicides formulated for human use. The microbicides evaluated were cellulose acetate phthalate (CAP), Carraguard, K-Y plus nonoxynol-9 (KY-N9), PRO 2000 (0.5 and 4%), SPL7013 (5%), UC781 (0.1 and 1%), and Vena Gel, along with their accompanying placebos. Products were evaluated for toxicity on cervical and colorectal epithelial cell lines, peripheral blood mononuclear cells (PBMCs), and macrophages (MΦ) by using an ATP release assay, and they were tested for their effect on transepithelial resistance (TER) of polarized epithelial monolayers. Anti-HIV-1 activity was evaluated in assays for transfer of infectious HIV-1 from epithelial cells to activated PBMCs and for PBMC and MΦ infection. CAP, Carraguard, PRO 2000, SPL7013, and UC781 along with their placebos were 20- to 50-fold less toxic than KY-N9 and Vena Gel. None of the nontoxic product concentrations disrupted the TER. Transfer of HIV-1
Ba-L
from epithelial cells to PBMCs and PBMC and MΦ infection with laboratory-adapted HIV-1
Ba-L
and HIV-1
LAI
isolates were inhibited by all products except Carraguard, KY-N9, and Vena Gel. KY-N9, Vena Gel, and Carraguard were not effective in blocking PBMC infection with primary HIV-1
A
, HIV-1
C
, and HIV-1
CRF01-AE
isolates. The concordance of these toxicity results with those previously reported indicates that our protocol may be useful for predicting toxicity in vivo. Moreover, our systematic anti-HIV-1 testing provides a rational basis for making better informed decisions about which products to consider for clinical trials.
Caspofungin Uptake Is Mediated by a High-Affinity Transporter in
Candida albicans
Authors: Paderu Padmaja , Park Steven , Perlin David S. 
Published: September 2004

ABSTRACT

The uptake of the echinocandin drug caspofungin acetate in
Candida albicans
was evaluated at drug levels at or near the MIC for the organism. Maximal uptake was achieved in 10 min and was energy independent. A saturable transport system, consistent with a facilitated-diffusion carrier, was observed with the unlabeled drug competing with the labeled drug for uptake and efflux. More than 90% of the transported drug was observed in a single kinetic compartment that was available for efflux, indicating that the drug was free in the cytoplasm following uptake. Efflux was also energy independent but was sensitive to the presence of a fully loaded carrier on both faces of the bilayer. Overall, the data presented are consistent with the presence of a high-affinity facilitated-diffusion transporter that mediates caspofungin uptake and could be a potential source of transport-related reduced susceptibility.
[
18
F]Ciprofloxacin, a New Positron Emission Tomography Tracer for Noninvasive Assessment of the Tissue Distribution and Pharmacokinetics of Ciprofloxacin in Humans
Authors: Brunner Martin , Langer Oliver , Dobrozemsky Georg , Müller Ulrich , Zeitlinger Markus , Mitterhauser Markus , Wadsak Wolfgang , Dudczak Robert , Kletter Kurt , Müller Markus 
Published: September 2004

ABSTRACT

The biodistribution and pharmacokinetics of the fluorine-18-labeled fluoroquinolone antibiotic [
18
F]ciprofloxacin in tissue were studied noninvasively in humans by means of positron emission tomography (PET). Special attention was paid to characterizing the distribution of [
18
F]ciprofloxacin to select target tissues. Healthy volunteers (
n
= 12) were orally pretreated for 5 days with therapeutic doses of unlabeled ciprofloxacin. On day 6, subjects received a tracer dose (mean injected amount, 700 ± 55 MBq, which contained about 0.6 mg of unlabeled ciprofloxacin) of [
18
F]ciprofloxacin as an intravenous bolus. Thereafter, PET imaging and venous blood sampling were initiated. Time-radioactivity curves were measured for liver, kidney, lung, heart, spleen, skeletal muscle, and brain tissues for up to 6 h after radiotracer administration. The first application of [
18
F]ciprofloxacin in humans has demonstrated the safety and utility of the newly developed radiotracer for pharmacokinetic PET imaging of the tissue ciprofloxacin distribution. Two different tissue compartments of radiotracer distribution could be identified. The first compartment including the kidney, heart, and spleen, from which the radiotracer was washed out relatively quickly (half-lives [
t
1/2
s], 68, 57, and 106 min, respectively). The second compartment comprised liver, muscle, and lung tissue, which displayed prolonged radiotracer retention (
t
1/2
, >130 min). The highest concentrations of radioactivity were measured in the liver and kidney, the main organs of excretion (standardized uptake values [SUVs], 4.9 ± 1.0 and 9.9 ± 4.4, respectively). The brain radioactivity concentrations were very low (<1 kBq · g
−1
) and could therefore not be quantified. Transformation of SUVs into absolute concentrations (in micrograms per milliliter) allowed us to relate the concentrations at the target site to the susceptibilities of bacterial pathogens. In this way, the frequent use of ciprofloxacin for the treatment of a variety of infections could be corroborated.
Mannose-Specific Plant Lectins from the
Amaryllidaceae
Family Qualify as Efficient Microbicides for Prevention of Human Immunodeficiency Virus Infection
Authors: Balzarini Jan , Hatse Sigrid , Vermeire Kurt , Princen Katrien , Aquaro Stefano , Perno Carlo-Federico , De Clercq Erik , Egberink Herman , Vanden Mooter Guy , Peumans Willy , Van Damme Els , Schols Dominique 
Published: September 2004

ABSTRACT

The plant lectins derived from
Galanthus nivalis
(Snowdrop) (GNA) and
Hippeastrum
hybrid (Amaryllis) (HHA) selectively inhibited a wide variety of human immunodeficiency virus type 1 (HIV-1) and HIV-2 strains and clinical (CXCR4- and CCR5-using) isolates in different cell types. They also efficiently inhibited infection of T lymphocytes by a variety of mutant virus strains. GNA and HHA markedly prevented syncytium formation between persistently infected HUT-78/HIV cells and uninfected T lymphocytes. The plant lectins did not measurably affect the antiviral activity of other clinically approved anti-HIV drugs used in the clinic when combined with these drugs. Short exposure of the lectins to cell-free virus particles or persistently HIV-infected HUT-78 cells markedly decreased HIV infectivity and increased the protective (microbicidal) activity of the plant lectins. Flow cytometric analysis and monoclonal antibody binding studies and a PCR-based assay revealed that GNA and HHA do not interfere with CD4, CXCR4, CCR5, and DC-SIGN and do not specifically bind with the membrane of uninfected cells. Instead, GNA and HHA likely interrupt the virus entry process by interfering with the virus envelope glycoprotein. HHA and GNA are odorless, colorless, and tasteless, and they are not cytotoxic, antimetabolically active, or mitogenic to human primary T lymphocytes at concentrations that exceed their antivirally active concentrations by 2 to 3 orders of magnitude. GNA and HHA proved stable at high temperature (50°C) and low pH (5.0) for prolonged time periods and can be easily formulated in gel preparations for microbicidal use; they did not agglutinate human erythrocytes and were not toxic to mice when administered intravenously.
Genomic Approach to Identification of Mutations Affecting Caspofungin Susceptibility in
Saccharomyces cerevisiae
Authors: Markovich Sarit , Yekutiel Aya , Shalit Itamar , Shadkchan Yona , Osherov Nir 
Published: September 2004

ABSTRACT

The antifungal agent caspofungin (CAS) specifically interferes with glucan synthesis and cell wall formation. To further study the cellular processes affected by CAS, we analyzed a
Saccharomyces cerevisiae
mutant collection (4,787 individual knockout mutations) to identify new genes affecting susceptibility to the drug. This collection was screened for increased CAS sensitivity (CAS-IS) or increased CAS resistance (CAS-IR). MICs were determined by the broth microdilution method. Disruption of 20 genes led to CAS-IS (four- to eightfold reductions in the MIC). Eleven of the 20 genes are involved in cell wall and membrane function, notably in the protein kinase C (PKC) integrity pathway (
MID2
,
FKS1
,
SMI1
, and
BCK1
), chitin and mannan biosynthesis (
CHS3
,
CHS4
,
CHS7
, and
MNN10
), and ergosterol biosynthesis (
ERG5
and
ERG6
). Four of the 20 genes (
TPO1
,
VPS65
,
VPS25
, and
CHC1
) are involved in vacuole and transport functions, 3 of the 20 genes (
CCR4
,
POP2
, and
NPL3
) are involved in the control of transcription, and 2 of the 20 genes are of unknown function. Disruption of nine additional genes led to CAS-IR (a fourfold increase of MIC). Five of these nine genes (
SLG1
,
ERG3
,
VRP1
,
CSG2
, and
CKA2
) are involved in cell wall function and signal transduction, and two of the nine genes (
VPS67
and
SAC2
) are involved in vacuole function. To assess the specificity of susceptibility to CAS, the MICs of amphotericin B, fluconazole, flucytosine, and calcofluor for the strains were tested. Seven of 20 CAS-IS strains (with disruption of
FKS1
,
SMI1
,
BCK1
,
CHS4
,
ERG5
,
TPO1
, and
ILM1
) and 1 of 9 CAS-IR strains (with disruption of
SLG1
) demonstrated selective susceptibility to CAS. To further explore the importance of PKC in CAS susceptibility, the activity of the PKC inhibitor staurosporine in combination with CAS was tested against eight
Aspergillus
clinical isolates by the microdilution assay. Synergistic or synergistic-to-additive activities were found against all eight isolates by use of both MIC and minimum effective concentration endpoints.
Fusidic Acid-Resistant Mutants of
Salmonella enterica
Serovar Typhimurium Have Low Levels of Heme and a Reduced Rate of Respiration and Are Sensitive to Oxidative Stress
Authors: Macvanin Mirjana , Ballagi Andras , Hughes Diarmaid 
Published: September 2004

ABSTRACT

Mutations in the translation elongation factor G (EF-G) make
Salmonella enterica
serovar Typhimurium resistant to the antibiotic fusidic acid. Fus
r
mutants are hypersensitive to oxidative stress and rapidly lose viability in the presence of hydrogen peroxide. We show that this phenotype is associated with reduced activity of two catalase enzymes, HPI (a bifunctional catalase-hydroperoxidase) and HPII (a monofunctional catalase). These catalases require the iron-binding cofactor heme for their activity. Fus
r
mutants have a reduced rate of transcription of
hemA
, a gene whose product catalyzes the first committed step in heme biosynthesis. Hypersensitivity of Fus
r
mutants to hydrogen peroxide is abolished by the presence of δ-aminolevulinic acid, the precursor of heme synthesis, in the growth media and by the addition of glutamate or glutamine, amino acids required for the first step in heme biosynthesis. Fluorescence measurements show that the level of heme in a Fus
r
mutant is significantly lower than it is in the wild type. Heme is also an essential cofactor of cytochromes in the electron transport chain of respiration. We found that the rate of respiration is reduced significantly in Fus
r
mutants. Sequestration of divalent iron in the growth media decreases the sensitivity of Fus
r
mutants to oxidative stress. Taken together, these results suggest that Fus
r
mutants are hypersensitive to oxidative stress because their low levels of heme reduce both catalase activity and respiration capacity. The sensitivity of Fus
r
mutants to oxidative stress could be associated with loss of viability due to iron-mediated DNA damage in the presence of hydrogen peroxide. We argue that understanding the specific nature of antibiotic resistance fitness costs in different environments may be a generally useful approach in identifying physiological processes that could serve as novel targets for antimicrobial agents.
Novel Concentration-Killing Curve Method for Estimation of Bactericidal Potency of Antibiotics in an In Vitro Dynamic Model
Authors: Liu Y. Q. , Zhang Y. Z. , Gao P. J. 
Published: September 2004

ABSTRACTThe bactericidal pharmacodynamics of antibiotics againstEscherichia coliwere analyzed by a concentration-killing curve (CKC) approach, and the novel parameters median bactericidal concentration (BC50) and bactericidal intensity (r) for bactericidal potency were proposed. By using the agar plate method, about 500E. colicells were inoculated onto Luria-Bertani plates containing a series of antibiotic concentrations, and after 24 h of incubation at 37°C, all the viable colonies were enumerated. This resulted in a sigmoidal CKC that could be perfectly fitted (R2> 0.9) with the functionN=N0/[1 + er(x− BC50)], whereNis number of colonies surviving on each plate with anxseries of concentrations of an antibiotic, andN0represents the meaningful inoculum size. Construction of the CKC method was based on the bactericidal effect of each antibiotic against the bacterial strain versus the concentration in two dimensions and may be a more valid, accurate, and reproducible method for estimating the bactericidal effect than the endpoint minimum bactericidal concentration (MBC) method. Mathematically, the CKC approach was point symmetrical toward its inflexion (BC50,N0/2); thus, 2BC50could replace MBC. The parameter BC1can be defined as BC50+ [ln(N0− 1)/r], which is the drug concentration at which only one colony survived and which is the least critical value of MBC in the CKC. The variater, which determined the tangent slope on inflexion whenN0was limited, could estimate the bactericidal intensity of an antibiotic. This verified that the CKC approach may be useful in studies with other classes of antibiotics and has considerable value as a tool for the accurate and proper administration of antibiotics.
VanD-Type Vancomycin-Resistant
Enterococcus faecium
and
Enterococcus faecalis
Authors: Depardieu Florence , Kolbert Mathias , Pruul Hendrik , Bell Jan , Courvalin Patrice 
Published: September 2004

ABSTRACT

Enterococcus faecium
clinical isolates A902 and BM4538, which were resistant to relatively high levels of vancomycin (128 and 64 μg/ml, respectively) and to low levels of teicoplanin (4 μg/ml), and
Enterococcus faecalis
clinical isolates BM4539 and BM4540, which were resistant to moderate levels of vancomycin (16 μg/ml) and susceptible to teicoplanin (0.25 μg/ml), were studied. They were constitutively resistant by synthesis of peptidoglycan precursors ending with
d
-alanyl-
d
-lactate and harbored a chromosomal
vanD
gene cluster which was not transferable by conjugation to other enterococci. VanX
D
activity, which is not required in the absence of
d
-Ala-
d
-Ala, was low in the four strains, although none of the conserved residues was mutated; and the constitutive VanY
D
activity in the membrane fractions was inhibited by penicillin G. The mutations E
13
G in the region of
d
-alanine:
d
-alanine ligase (which is implicated in
d
-Ala1 binding in A902) and S
319
N of the serine involved in ATP binding in BM4538 and a 7-bp insertion at different locations in BM4539 and BM4540 (which led to putative truncated proteins) led to the production of an impaired enzyme and accounted for the lack of
d
-Ala-
d
-Ala-containing peptidoglycan precursors. The same 7-bp insertion in

vanS
D

of BM4539 and BM4540 and a 1-bp deletion in

vanS
D

of A902, which in each case led to a putative truncated and presumably nonfunctional protein, could account for the constitutive resistance. Strain BM4538, with a functional VanS
D
, had a G
140
E mutation in VanR
D
that could be responsible for constitutive glycopeptide resistance. This would represent the first example of constitutive
van
gene expression due to a mutation in the structural gene for a VanR transcriptional activator. Study of these four additional strains that could be distinguished on the basis of their various assortments of mutations confirmed that all VanD-type strains isolated so far have mutations in the
ddl
housekeeping gene and in the acquired

vanS
D

or

vanR
D

gene that lead to constitutive resistance to vancomycin.
Human Immunodeficiency Virus Type 1 Protease Inhibitors Block Toll-Like Receptor 2 (TLR2)- and TLR4-Induced NF-κB Activation
Authors: Equils Ozlem , Shapiro Alan , Madak Zeynep , Liu Chunren , Lu Daning 
Published: September 2004

ABSTRACTCoinfections with opportunistic and pathogenic bacteria induce human immunodeficiency virus (HIV) replication through microbial antigen activation of NF-κB. Here, we assessed whether HIV type 1 protease inhibitors (PI) block microbial antigen activation of NF-κB. Human microvessel endothelial cells were transiently transfected with either endothelial cell-leukocyte adhesion molecule NF-κB luciferase or interleukin 6 (IL-6) promoter luciferase constructs by using FuGENE 6, and they were treated with PI (nelfinavir, ritonavir, or saquinavir) prior to stimulation with the Toll-like receptor 4 (TLR4) and TLR2 ligands, with lipopolysaccharide (LPS), solubleMycobacterium tuberculosisfactor, orStaphylococcus epidermidisphenol-soluble modulin, respectively, or with tumor necrosis factor alpha (TNF-α). Luciferase activity was measured by using a Promega luciferase kit. TNF-α release from the supernatant was measured by enzyme-linked immunosorbent assay. Cell death was assessed by lactate dehydrogenase assay. We observed that PI pretreatment blocked the TLR2- and TLR4- as well as the TNF-α-mediated NF-κB activation, in a dose-dependent manner. PI pretreatment also blocked the LPS-induced IL-6 promoter transactivation and TNF-α secretion. These data suggest that PI block HIV replication not only by inhibiting the HIV protease but also by blocking the TLR- and TNF-α-mediated NF-κB activation and proinflammatory cytokine production. These findings may help explain the immunomodulatory effects of PI, and they suggest an advantage for PI-containing drug regimens in the treatment of HIV-infected patients who are coinfected with opportunistic and pathogenic bacteria.
Long Depletion Time of Enrofloxacin in Rainbow Trout (
Oncorhynchus mykiss
)
Authors: Lucchetti Dario , Fabrizi Laura , Guandalini Emilio , Podestà Elisabetta , Marvasi Luigi , Zaghini Anna , Coni Ettore 
Published: September 2004

ABSTRACT

The international production of farmed fish has been growing continuously over recent years. Until now few veterinary drugs have been approved by the European Union for use in aquaculture, and this has favored the off-label use of products authorized for use in food-producing animal species different from fishes among fish farmers. Adequate field studies are lacking, especially for those species called minor species which are consumed extensively only in some European countries. In the present investigation we studied the depletion of the fluoroquinolone antibacterial enrofloxacin over time in a minor species, the rainbow trout (
Oncorhynchus mykiss
), reared on a real fish farm and treated with medicated feed (10 mg kg of trout body weight
−1
day
−1
). Edible tissue samples (muscle plus skin in natural proportions) and fish bone samples were analyzed for enrofloxacin and for its major metabolite, ciprofloxacin, by high-performance liquid chromatography with fluorescence detection at different times after the end of treatment. Our results show that at 500°C-day (in which degree-days are calculated by multiplying the mean daily water temperature by the total number of days on which the temperature was measured), which is the minimum withdrawal period established by European Economic Commission Directive No. 82/2001 for any type of product administered off-label, edible trout tissues might still contain about 170 μg of enrofloxacin kg
−1
, whereas the maximum residue level for enrofloxacin plus ciprofloxacin is set at 100 μg kg
−1
. To our knowledge, no studies of the depletion of enrofloxacin in rainbow trout have been performed. On the basis of the data obtained in the present study, we suggest a more appropriate withdrawal time of 816°C-day for the sum of enrofloxacin plus ciprofloxacin levels in rainbow trout muscle plus skin tissues.