bluuebunny/crossref_metadata_2025 huggingface dataset:
Cellular Uptake and Efflux of Azithromycin, Erythromycin, Clarithromycin, Telithromycin, and Cethromycin
Authors: Bosnar Martina , Kelnerić Željko , Munić Vesna , Eraković Vesna , Parnham Michael J.
Published: May 2005

Macrolide antibiotics have an outstanding ability to concentrate within host cells, particularly phagocytes. In the study described in this paper five different macrolide antibiotics were compared regarding the uptake and release kinetics in human peripheral blood polymorphonuclear neutrophils (PMNs) and three different cell lines, two phagocytic cell lines (RAW 264.7 and THP-1) and an epithelial cell line (MDCK). Based on the results obtained, the substances tested could be clustered into different groups. Azithromycin constituted the first group, characterized by rapid and nonsaturable uptake into phagocytic cells and a high degree of retention in the preloaded cells. The second group included erythromycin and clarithromycin. These two substances do not exhibit cell specificity; consequently, they are taken up to a similar extent and are released by all cell types studied. Ketolides constituted the last group. Their uptake was saturable in cells of monocytic lineage as well as in nondifferentiated cells of myeloid lineage, and they were rapidly released from all the cell lines studied. However, in PMNs, ketolide uptake was not saturable; and unlike telithromycin, cethromycin rapidly egressed from the loaded cells.
Antimycobacterial Agents Differ with Respect to Their Bacteriostatic versus Bactericidal Activities in Relation to Time of Exposure, Mycobacterial Growth Phase, and Their Use in Combination
Authors: Bakker-Woudenberg Irma A. J. M. , van Vianen Wim , van Soolingen Dick , Verbrugh Henri A. , van Agtmael Michiel A.
Published: May 2005

A number of antimycobacterial agents were evaluated with respect to their bacteriostatic activity (growth inhibition) versus the bactericidal activity against a clinical isolate of
Mycobacterium avium
(
Mycobacterium avium
complex [MAC] strain 101) in relation to the time of exposure and the growth phase of the mycobacteria. In terms of growth inhibition the MAC in the active phase of growth was susceptible to clarithromycin, ethambutol, rifampin, amikacin, and the quinolones moxifloxacin, ciprofloxacin, and sparfloxacin. In terms of bactericidal activity in relation to the time of exposure these agents differed substantially with respect to the killing rate. An initial high killing capacity at low concentration was observed for amikacin, which in this respect was superior to the other agents. The bactericidal activity of clarithromycin and ethambutol was only seen at relatively high concentrations and increased with time. Killing by rifampin was concentration dependent as well as time dependent. The bactericidal activity of moxifloxacin was marginally dependent on the concentration or the time of exposure. The activity of clarithromycin in combination with ethambutol was not significantly enhanced compared to single-agent exposure. Only an additive effect was observed. The addition of rifampin or moxifloxacin as a third agent only marginally effected increased killing of MAC. However, by addition of amikacin the activity of the clarithromycin-ethambutol combination was significantly improved. The combination of amikacin and amoxicillin-clavulanic acid exhibited synergistic antimycobacterial activity. Towards MAC at low growth rates, only the quinolones exhibited a bactericidal effect.
Proline Conformation-Dependent Antimicrobial Activity of a Proline-Rich Histone H1 N-Terminal Peptide Fragment Isolated from the Skin Mucus of Atlantic Salmon
Authors: Lüders Torben , Birkemo Gunn Alice , Nissen-Meyer Jon , Andersen Øivind , Nes Ingolf F.
Published: May 2005

A 30-residue N-terminally acetylated peptide derived from the N-terminal part of histone H1 was identified as the dominant antimicrobial peptide in skin mucus from Atlantic salmon (
Salmo salar
). The peptide (termed salmon antimicrobial peptide [SAMP H1]) was purified to homogeneity by a combination of reversed-phase and cation-exchange chromatographies. By Edman degradation of the deacetylated peptide and by sequencing of the PCR-amplified DNA that encodes the peptide, the complete amino acid sequence was determined to be AEVAPAPAAAAPAKAPKKKAAAKPKKAGPS. The theoretical molecular weight of N-terminally acetylated SAMP H1 was calculated to be 2,836, which is the same as that determined by matrix-assisted laser desorption ionization mass spectrometry. The peptide was active against both gram-negative and -positive bacteria. The N-terminal acetyl group was not necessary for activity since deacetylation did not reduce the activity. A synthetic peptide whose sequence was identical to that of the isolated fragment was initially inactive but could be activated by binding it to a cation-exchange column. Treatment of the synthetic peptide when it was bound to the exchange column with peptidylproline
cis
-
trans
-isomerase increased the amount of active peptide, indicating that isomerization of the proline peptide bond(s) was necessary for activation of the synthetic peptide. Comparison of the active and inactive forms by circular dichroism and chromatographic analyses suggests that the active form, both the natural and the synthetic forms, is more structured, condensed, and rigid than the inactive form, which has a more nonstructured conformation. This work shows for the first time the importance of proline isomers in the activity of an antimicrobial peptide.
Effects of a High-Fat Meal on the Relative Oral Bioavailability of Piperaquine
Authors: Sim Ing-Kye , Davis Timothy M. E. , Ilett Kenneth F.
Published: May 2005

Piperaquine (PQ) is an antimalarial drug whose high lipid solubility suggests that its absorption can be increased by a high-fat meal. We examined the pharmacokinetics of PQ phosphate (500 mg given orally) in the fasting state and after a high-fat meal in eight healthy Caucasian volunteers (randomized crossover). Plasma PQ concentration-time profiles were analyzed by using noncompartmental pharmacokinetic analysis. In the fed state, the geometric mean
C
max
increased by 213%, from 21.0 to 65.8 μg/liter (
P
< 0.001). The time of
C
max
was not significantly different between the fasting and fed states. The geometric mean area under the concentration-time curve from zero onward (AUC
0-∞
) increased by 98%, from 3,724 to 7,362 μg h/liter (
P
= 0.006). The oral bioavailability of PQ relative to the fasting state was 121% greater after the high-fat meal (95% confidence interval, 26 to 216% increase;
P
= 0.020). The side effects, postural blood pressure changes, electrocardiographic corrected QT interval, serum glucose, and other biochemical and hematological indices were similar in the fasting and fed states over 28 days of follow-up.
Effects of Acyl versus Aminoacyl Conjugation on the Properties of Antimicrobial Peptides
Authors: Radzishevsky Inna S. , Rotem Shahar , Zaknoon Fadia , Gaidukov Leonid , Dagan Arie , Mor Amram
Published: May 2005

To investigate the importance of increased hydrophobicity at the amino end of antimicrobial peptides, a dermaseptin derivative was used as a template for a systematic acylation study. Through a gradual increase of the acyl moiety chain length, hydrophobicity was monitored and further modulated by acyl conversion to aminoacyl. The chain lengths of the acyl derivatives correlated with a gradual increase in the peptide's global hydrophobicity and stabilization of its helical structure. The effect on cytolytic properties, however, fluctuated for different cells. Whereas acylation gradually enhanced hemolysis of human red blood cells and antiprotozoan activity against
Leishmania major
, bacteria displayed a more complex behavior. The gram-positive organism
Staphylococcus aureus
was most sensitive to intermediate acyl chains, while longer acyls gradually led to a total loss of activity. All acyl derivatives were detrimental to activity against
Escherichia coli
, namely, but not solely, because of peptide aggregation. Although aminoacyl derivatives behaved essentially similarly to the nonaminated acyls, they displayed reduced hydrophobicity, and consequently, the long-chain acyls enhanced activity against all microorganisms (e.g., by up to 12-fold for the aminolauryl derivative) but were significantly less hemolytic than their acyl counterparts. Acylation also enhanced bactericidal kinetics and peptide resistance to plasma proteases. The similarities and differences upon acylation of MSI-78 and LL37 are presented and discussed. Overall, the data suggest an approach that can be used to enhance the potencies of acylated short antimicrobial peptides by preventing hydrophobic interactions that lead to self-assembly in solution and, thus, to inefficacy against cell wall-containing target cells.
Pharmacokinetics and Pharmacodynamics of Imipenem during Continuous Renal Replacement Therapy in Critically Ill Patients
Authors: Fish Douglas N. , Teitelbaum Isaac , Abraham Edward
Published: May 2005

The pharmacokinetics of imipenem were studied in adult intensive care unit (ICU) patients during continuous venovenous hemofiltration (CVVH;
n
= 6 patients) or hemodiafiltration (CVVHDF;
n
= 6 patients). Patients (mean ± standard deviation age, 50.9 ± 15.9 years; weight, 98.5 ± 15.9 kg) received imipenem at 0.5 g every 8 to 12 h (total daily doses of 1 to 1.5 g/day) by intravenous infusion over 30 min. Pre- and postmembrane blood (plasma) and corresponding ultrafiltrate or dialysate samples were collected 1, 2, 4, and 8 or 12 h (depending on dosing interval) after completion of the drug infusion. Drug concentrations were measured using validated high-performance liquid chromatography methods. Mean systemic clearance (CL

S

) and elimination half-life (
t
1/2
) of imipenem were 145 ± 18 ml/min and 2.7 ± 1.3 h during CVVH versus 178 ± 18 ml/min and 2.6 ± 1.6 h during CVVHDF, respectively. Imipenem clearance was substantially increased during both CVVH and CVVHDF, with membrane clearance representing 25% and 32% of CL

S

, respectively. The results of this study indicate that CVVH and CVVHDF contribute to imipenem clearance to a greater degree than previously reported. Imipenem doses of 1.0 g/day appear to achieve concentrations adequate to treat most common gram-negative pathogens (MIC up to 2 μg/ml) during CVVH or CVVHDF, but doses of 2.0 g/day or more may be required to adequately treat and prevent resistance in pathogens with higher MICs (MIC = 4 to 8 μg/ml). Higher doses should only be used after consideration of potential central nervous system toxicities or other risks of therapy in these severely ill patients.
Influence of Efflux Transporters on the Accumulation and Efflux of Four Quinolones (Ciprofloxacin, Levofloxacin, Garenoxacin, and Moxifloxacin) in J774 Macrophages
Authors: Michot Jean-Michel , Seral Cristina , Van Bambeke Françoise , Mingeot-Leclercq Marie-Paule , Tulkens Paul M.
Published: May 2005

Ciprofloxacin is subject to efflux from J774 macrophages through a multidrug resistance-related protein-like transporter (J. M. Michot, F. Van Bambeke, M. P. Mingeot-Leclercq, and P. M. Tulkens, Antimicrob. Agents Chemother.48:2673-2682, 2004). Here, we compare ciprofloxacin to levofloxacin, garenoxacin, and moxifloxacin for transport. At 4 mg/liter, an apparent steady state in accumulation was reached after 30 to 60 min for all quinolones but to quite different levels (approximately 3, 5, 10, and 16 fold). Accumulation of ciprofloxacin was increased (to about 16 to 20 fold) by ATP depletion, increase in extracellular concentration, and the addition of probenecid, gemfibrozil, or MK571 (but not verapamil or GF120918). These treatments did not affect the accumulation of moxifloxacin. Levofloxacin and garenoxacin showed an intermediate behavior. Efflux of ciprofloxacin was slowed down by probenecid (half-life, 7.2 versus 1.6 min). Moxifloxacin efflux was faster and unaffected by probenecid (half-lifes, 0.27 versus 0.33 min). Efflux of levofloxacin and garenoxacin was modestly decreased by probenecid (1.5 and 2.1 fold). Accumulation of14C-labeled ciprofloxacin was increased by unlabeled ciprofloxacin and moxifloxacin, but moxifloxacin was two times less potent. Accumulation of moxifloxacin at 4°C was almost identical to that at 37°C, whereas that of ciprofloxacin was minimal (levofloxacin and garenoxacin showed intermediate behaviors). Cells subjected to thermal shock (56°C; 10 min) accumulated all quinolones at a similar level (16 to 23 fold). We conclude that moxifloxacin is apparently not subject to efflux from J774 macrophages, even though it can interact with the ciprofloxacin transporter. Levofloxacin and garenoxacin are partially effluxed. Data suggest that efflux plays an important role in the differential accumulation of quinolones by J774 macrophages.
Comparable Efficacies of the Antimicrobial Peptide Human Lactoferrin 1-11 and Gentamicin in a Chronic Methicillin-Resistant
Staphylococcus aureus
Osteomyelitis Model
Authors: Faber Christopher , Stallmann Hein P. , Lyaruu D. M. , Joosten Uwe , von Eiff Christof , van Nieuw Amerongen Arie , Wuisman Paul I. J. M.
Published: May 2005

The therapeutic efficacy of an antimicrobial peptide, human lactoferrin 1-11 (hLF1-11), was investigated in a model of chronic methicillin-resistant
Staphylococcus aureus
(MRSA) (gentamicin susceptible) osteomyelitis in rabbits. We incorporated 50 mg hLF1-11/g or 50 mg gentamicin/g cement powder into a calcium phosphate bone cement (Ca-P) and injected it into the debrided tibial cavity, creating a local drug delivery system. The efficacy of hLF1-11 and gentamicin was compared to that of a sham-treated control (plain bone cement) (
n
= 6) and no treatment (infected only) (
n
= 5). The results were evaluated by microbiology, radiology, and histology. MRSA was recovered from all tibias in both control groups (
n
= 11). On the other hand, hLF1-11 and gentamicin significantly reduced the bacterial load. Furthermore, no growth of bacteria was detected in five out of eight and six out of eight specimens of the hLF1-11- and gentamicin-treated groups, respectively. These results were confirmed by a significant reduction of the histological disease severity score by hLF1-11 and gentamicin compared to both control groups. The hLF1-11-treated group also had a significantly lower radiological score compared to the gentamicin-treated group. This study demonstrates the efficacy of hLF1-11 incorporated into Ca-P bone cement as a possible therapeutic strategy for the treatment of osteomyelitis, showing efficacy comparable to that of gentamicin. Therefore, the results of this study warrant further preclinical investigations into the possibilities of using hLF1-11 for the treatment of osteomyelitis.
Antifungal Protein PAF Severely Affects the Integrity of the Plasma Membrane ofAspergillus nidulansand Induces an Apoptosis-Like Phenotype
Authors: Leiter Éva , Szappanos Henrietta , Oberparleiter Christoph , Kaiserer Lydia , Csernoch László , Pusztahelyi Tünde , Emri Tamás , Pócsi István , Salvenmoser Willibald , Marx Florentine
Published: May 2005

The small, basic, and cysteine-rich antifungal protein PAF is abundantly secreted into the supernatant by the β-lactam producerPenicillium chrysogenum. PAF inhibits the growth of various important plant and zoopathogenic filamentous fungi. Previous studies revealed the active internalization of the antifungal protein and the induction of multifactorial detrimental effects, which finally resulted in morphological changes and growth inhibition in target fungi. In the present study, we offer detailed insights into the mechanism of action of PAF and give evidence for the induction of a programmed cell death-like phenotype. We proved the hyperpolarization of the plasma membrane in PAF-treatedAspergillus nidulanshyphae by using the aminonaphtylethenylpyridinium dye di-8-ANEPPS. The exposure of phosphatidylserine on the surface ofA. nidulansprotoplasts by Annexin V staining and the detection of DNA strand breaks by TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling) gave evidence for a PAF-induced apoptotic-like mechanism inA. nidulans. The localization of reactive oxygen species (ROS) by dichlorodihydrofluorescein diacetate and the abnormal cellular ultrastructure analyzed by transmission electron microscopy suggested that ROS-elicited membrane damage and the disintegration of mitochondria played a major role in the cytotoxicity of PAF. Finally, the reduced PAF sensitivity ofA. nidulansstrain FGSC1053, which carries a dominant-interfering mutation infadA, supported our assumption that G-protein signaling was involved in PAF-mediated toxicity.
Small Molecules VP-14637 and JNJ-2408068 Inhibit Respiratory Syncytial Virus Fusion by Similar Mechanisms
Authors: Douglas Janet L. , Panis Marites L. , Ho Edmund , Lin Kuei-Ying , Krawczyk Steve H. , Grant Deborah M. , Cai Ruby , Swaminathan Swami , Chen Xiaowu , Cihlar Tomas
Published: May 2005

Here we present data on the mechanism of action of VP-14637 and JNJ-2408068 (formerly R-170591), two small-molecule inhibitors of respiratory syncytial virus (RSV). Both inhibitors exhibited potent antiviral activity with 50% effective concentrations (EC
50
s) of 1.4 and 2.1 nM, respectively. A similar inhibitory effect was observed in a RSV-mediated cell fusion assay (EC
50
= 5.4 and 0.9 nM, respectively). Several drug-resistant RSV variants were selected in vitro in the presence of each compound. All selected viruses exhibited significant cross-resistance to both inhibitors and contained various single amino acid substitutions in two distinct regions of the viral F protein, the heptad repeat 2 (HR2; mutations D486N, E487D, and F488Y), and the intervening domain between HR1 and HR2 (mutation K399I and T400A). Studies using [
3
H]VP-14637 revealed a specific binding of the compound to RSV-infected cells that was efficiently inhibited by JNJ-2408068 (50% inhibitory concentration = 2.9 nM) but not by the HR2-derived peptide T-118. Further analysis using a transient T7 vaccinia expression system indicated that RSV F protein is sufficient for this interaction. F proteins containing either the VP-14637 or JNJ-2408068 resistance mutations exhibited greatly reduced binding of [
3
H]VP-14637. Molecular modeling analysis suggests that both molecules may bind into a small hydrophobic cavity in the inner core of F protein, interacting simultaneously with both the HR1 and HR2 domains. Altogether, these data indicate that VP-14637 and JNJ-2408068 interfere with RSV fusion through a mechanism involving a similar interaction with the F protein.
Use of Confocal Microscopy To Analyze the Rate of Vancomycin Penetration through
Staphylococcus aureus
Biofilms
Authors: Jefferson Kimberly K. , Goldmann Donald A. , Pier Gerald B.
Published: May 2005

When bacteria assume the biofilm mode of growth, they can tolerate levels of antimicrobial agents 10 to 1,000 times higher than the MICs of genetically equivalent planktonic bacteria. The properties of biofilms that give rise to antibiotic resistance are only partially understood. Inhibition of antibiotic penetration into the biofilm may play a role, but this has not been proven directly. In this report, penetration of the glycopeptide antibiotic vancomycin into viable
Staphylococcus aureus
biofilms was analyzed by confocal scanning laser microscopy using a fluorescently labeled derivative of the drug. We found that while vancomycin bound to free-floating bacteria in water within 5 min, it took more than 1 h to bind to cells within the deepest layers of a biofilm. These results indicate that the antibiotic is transported through the depth of the biofilm but that the rate is significantly reduced with respect to its transport through flowing water. This suggests that, whereas planktonic bacteria were rapidly exposed to a full bolus of vancomycin, the bacteria in the deeper layers of the biofilm were exposed to a gradually increasing dose of the drug due to its reduced rate of penetration. This gradual exposure may allow the biofilm bacteria to undergo stress-induced metabolic or transcriptional changes that increase resistance to the antibiotic. We also investigated the role of poly-
N
-acetylglucosamine, an important component of the
S. aureus
biofilm matrix, and found that its production was not involved in the observed decrease in the rate of vancomycin penetration.
Mechanisms of Antibacterial Action of Three Monoterpenes
Authors: Trombetta Domenico , Castelli Francesco , Sarpietro Maria Grazia , Venuti Vincenza , Cristani Mariateresa , Daniele Claudia , Saija Antonella , Mazzanti Gabriela , Bisignano Giuseppe
Published: May 2005

In the present paper, we report the antimicrobial efficacy of three monoterpenes [linalyl acetate, (+)menthol, and thymol] against the gram-positive bacterium
Staphylococcus aureus
and the gram-negative bacterium
Escherichia coli
. For a better understanding of their mechanisms of action, the capability of these three monoterpenes to damage biomembranes was evaluated by monitoring the release, following exposure to the compounds under study, of the water-soluble fluorescent marker carboxyfluorescein from unilamellar vesicles with different lipidic compositions (phosphatidylcholine, phosphatidylcholine/phosphatidylserine [9:1], phosphatidylcholine/stearylamine [9:1], and phosphatidylglycerol/cardiolipin [9:1]). Furthermore, the interaction of the terpenes tested with dimyristoylphosphatidylcholine multilamellar vesicles as model membranes was monitored by means of differential scanning calorimetry. Finally, the results were related to the relative lipophilicity and water solubility of the compounds examined. Taken together, our findings lead us to speculate that the antimicrobial effect of (+)menthol, thymol, and linalyl acetate may result, at least partially, from a perturbation of the lipid fraction of microorganism plasma membrane, resulting in alterations of membrane permeability and in leakage of intracellular materials. Besides being related to physicochemical characteristics of the drugs (such as lipophilicity and water solubility), this effect seems to be dependent on lipid composition and net surface charge of microbial membranes. Furthermore, the drugs might cross the cell membranes, penetrating into the interior of the cell and interacting with intracellular sites critical for antibacterial activity.
Novel Ser79Leu and Ser81Ile Substitutions in the Quinolone Resistance-Determining Regions of ParC Topoisomerase IV and GyrA DNA Gyrase Subunits from Recent Fluoroquinolone-Resistant
Streptococcus pneumoniae
Clinical Isolates
Authors: Korzheva Nataliya , Davies Todd A. , Goldschmidt Raul
Published: May 2005

Resistance of
Streptococcus pneumoniae
to fluoroquinolones is caused predominantly by amino acid substitutions at positions Ser79 of ParC and Ser81 of GyrA to either Phe or Tyr encoded in the quinolone resistance-determining regions of the
parC
topoisomerase IV and
gyrA
DNA gyrase genes. Analysis of highly resistant clinical isolates identified novel second-step substitutions, Ser79Leu (ParC) and Ser81Ile (GyrA). To determine contributions of these new mutations to fluoroquinolone resistance either alone or in combination with other Ser79/81 alleles, the substitutions Ser79Leu/Phe/Tyr in ParC and Ser81Ile/Phe/Tyr in GyrA were introduced into the R6 background, resulting in 15 isogenic strains. Their level of fluoroquinolone resistance was determined by susceptibility testing for ciprofloxacin, levofloxacin, moxifloxacin, gatifloxacin, gemifloxacin, garenoxacin, and norfloxacin. Leu79 and Ile81 alone as well as 79/81Phe/Tyr substitutions did not contribute significantly to resistance, with fluoroquinolone MICs increasing two- to fourfold compared to wild type for all agents tested. Fluoroquinolone MICs for double transformants ParC Ser79Phe/Tyr/Leu-GyrA Ser81Phe/Tyr were uniformly increased by 8- to 64-fold regardless of pairs of amino acid substitutions. However, combinations including Ile81 conferred two- to fourfold-higher levels of resistance than did combinations including any other Ser81 GyrA substitution, thus demonstrating the differential effects of diverse amino acid substitutions at particular hotspots on fluoroquinolone MICs.
In Vitro Activity of Telithromycin against Macrolide-Susceptible and Macrolide-Resistant Pharyngeal Isolates of Group A Streptococci in the United States
Authors: Green Michael , Allen Coburn , Bradley John , Dashefsky Barry , Gilsdorf Janet R. , Marcon Mario J. , Schutze Gordon E. , Smith Clay , Walter Emmanuel , Martin Judith M. , Edwards Kathryn A. , Barbadora Karen A. , Rumbaugh Renee M. , Wald Ellen R.
Published: May 2005

In vitro susceptibility testing of 2,797 group A streptococcus (GAS) isolates demonstrated that telithromycin was fully active against all macrolide-susceptible strains and among 80 of 115 macrolide-resistant GAS expressing the M phenotype. Telithromycin resistance was identified in 2 of 45 strains expressing the inducible macrolide-lincosamide-streptogramin B phenotype and four of nine isolates expressing the constitutive macrolide-lincosamide-streptogramin B resistance phenotype.
DNA in Antibiotic Preparations: Absence of Intact Resistance Genes
Authors: Woegerbauer Markus , Lagler Heimo , Graninger Wolfgang , Burgmann Heinz
Published: May 2005

Fragments of
erm
(E2),
otrA
, and
aph
(6) shorter than 400 bp and producer strain-specific rRNA genes were amplified from various antibiotics. The amount of genetic material and the sizes of amplicons recovered from murine feces after oral administration of a β-lactamase-encoding plasmid indicated substantial DNA degradation in the mammalian gastrointestinal tract. These observations imply that antibiotics are no major source for horizontal resistance gene transfer in clinical settings.
In Vitro and In Vivo Activities of DA-7867, a New Oxazolidinone, against Aerobic Gram-Positive Bacteria
Authors: Yoon Eun Jeong , Jo Yeong Woo , Choi Sung Hak , Lee Tae Ho , Rhee Jae Keol , Yoo Moohi , Shim Mi Ja , Choi Eung Chil
Published: May 2005

In vitro and in vivo activities of DA-7867 were assessed against methicillin-resistant
Staphylococcus aureus
, vancomycin-resistant enterococci, and penicillin-resistant
Streptococcus pneumoniae
. All isolates were inhibited by DA-7867 at ≤0.78 μg/ml, a four-times-lower concentration than that of inhibition by linezolid. For murine infection models, DA-7867 also exhibited greater efficacy than linezolid against all isolates tested.
Biosynthesized Tea Polyphenols Inactivate
Chlamydia trachomatis
In Vitro
Authors: Yamazaki Tsutomu , Kishimoto Toshio , Shiga Sadashi , Sato Kozue , Hagiwara Toshikatsu , Inoue Miyuki , Sasaki Nozomu , Ouchi Kazunobu , Hara Yukihiko
Published: May 2005

Biosynthesized tea polyphenols showed antichlamydial activity against
Chlamydia trachomatis
D/UW-3/Cx and L
2
/434/Bu using cell culture. The most active compounds were (−)-epigallocatechin gallate and (−)-epicatechin gallate, followed by (−)-epicatechin (EC). (+)-Epicatechin and (−)-epigallocatechin were intermediate. EC was the least toxic. These results warrant evaluation of tea polyphenols as topical antichlamydial agents.
Population Pharmacokinetics of Abacavir in Plasma and Cerebrospinal Fluid
Authors: Capparelli Edmund V. , Letendre Scott L. , Ellis Ronald J. , Patel Parul , Holland Diane , McCutchan J. Allen
Published: May 2005

The distribution of abacavir into the cerebrospinal fluid (CSF) was assessed by use of a population pharmacokinetic analysis. Plasma and CSF abacavir concentrations in 54 subjects were determined. The abacavir CSF/plasma ratio averaged 36% and increased throughout the dose interval. Abacavir penetrates into the CSF in adequate concentrations to inhibit local human immunodeficiency virus replication.
In Vitro Inhibitory Effects of Hinokitiol on Proliferation of
Chlamydia trachomatis
Authors: Yamano Hiroaki , Yamazaki Tsutomu , Sato Kozue , Shiga Sadashi , Hagiwara Toshikatsu , Ouchi Kazunobu , Kishimoto Toshio
Published: May 2005

The inhibitory effects of hinokitiol (β-thujaplicin) on
Chlamydia trachomatis
D/UW-3/Cx were shown by MIC, minimum lethal concentration (MLC), and preinoculation minimal microbicidal concentration assays using HeLa 229 cells. The MIC and the MLC were both 32 μg/ml. Further evaluation of hinokitiol as a topical agent against
C. trachomatis
is warranted.
Detection of
qnr
in Clinical Isolates of
Escherichia coli
from Korea
Authors: Jeong Jin-Yong , Yoon Hyun Jung , Kim Eun Sil , Lee Yoola , Choi Sang-Ho , Kim Nam Joong , Woo Jun Hee , Kim Yang Soo
Published: May 2005

qnr
was detected in 2 of 260
Escherichia coli
clinical isolates collected from a Korean hospital during the period 2001 to 2003. The two strains were not clonally related.
qnr
was located in In4 family class 1 integrons of original structure, downstream of orf513 and upstream from another resistance gene (
dfrA3b
) and a gene of unknown function (orf105). Transfer of the
qnr
determinant by conjugation could be detected from only one strain.
Effect of CYP3A1(23) Induction on Clarithromycin Pharmacokinetics in Rats with Diabetes Mellitus
Authors: Kim Yu C. , Lee Joo H. , Kim So H. , Lee Myung G.
Published: May 2005

After intravenous and oral administration of clarithromycin at a dose of 20 mg/kg of body weight to rats with diabetes mellitus induced by alloxan (DMIA) and diabetes mellitus induced by streptozotocin (DMIS), the area under the curve values were significantly smaller than those of respective control rats. The in vitro intrinsic clearance values for the disappearance of clarithromycin were significantly faster in both rats with DMIA and rats with DMIS than in control rats. The above data suggested that metabolism of clarithromycin increased in both types of diabetic rat due to an increase in the expression and mRNA level of CYP3A1(23) in the rats.
In Vitro and Intracellular Activities of LBM415 (NVP PDF-713) against
Legionella pneumophila
Authors: Edelstein Paul H. , Hu Baofeng , Edelstein Martha A. C.
Published: May 2005

LBM415 activity against extracellular and intracellular
Legionella pneumophila
was studied. The LBM415 MIC
50
for 20
Legionella
sp. strains was 4 μg/ml, versus 0.06, 0.25, and ≤ 0.03 μg/ml for azithromycin, erythromycin, and levofloxacin, respectively. LBM415 (0.5 and 16 μg/ml) reversibly prevented intracellular growth of two
L. pneumophila
strains and was less active than erythromycin.
Targeted Gene Disruption of the 14-α Sterol Demethylase (
cyp51A
) in
Aspergillus fumigatus
and Its Role in Azole Drug Susceptibility
Authors: Mellado E. , Garcia-Effron G. , Buitrago M. J. , Alcazar-Fuoli L. , Cuenca-Estrella M. , Rodriguez-Tudela J. L.
Published: May 2005

The role of
Aspergillus fumigatus
14α-sterol demethylase (Cyp51A) in azole drug susceptibility was assessed. Targeted disruption of
cyp51A
in azole-susceptible and -resistant strains decreased MICs from 2- to 40-fold. The
cyp51A
mutants were morphologically indistinguishable from the wild-type strain, retaining the ability to cause pulmonary disease in neutropenic mice.
In Vitro Activities of Amphotericin B and Voriconazole against Aleurioconidia from
Aspergillus terreus
Authors: Lass-Flörl Cornelia , Rief Alexandra , Leitner Sandra , Speth Cornelia , Würzner Reinhard , Dierich Manfred P.
Published: May 2005

This study used aleurioconidia as inoculum and compared the MICs of amphotericin B and voriconazole to those obtained for conidia of 31
Aspergillus terreus
strains. For conidia and aleurioconidia, the MIC at which 90% of strains were inhibited was 2.5 μg/ml and 5 μg/ml with amphotericin B and 1 μg/ml and 2 μg/ml with voriconazole.
Comparative In Vitro Activities of Investigational Peptide Deformylase Inhibitor NVP LBM-415 and Other Agents against Human Mycoplasmas and Ureaplasmas
Authors: Waites Ken B. , Reddy Nipun B. , Crabb Donna M. , Duffy Lynn B.
Published: May 2005

Peptide deformylase inhibitor LBM-415 and seven other drugs were tested againstMycoplasma pneumoniae(100 isolates),Mycoplasma hominis(20 isolates),Mycoplasma fermentans(10 isolates), andUreaplasmaspecies (50 isolates). LBM-415 was active againstM. pneumoniae(MICs, ≤0.008 μg/ml). It showed no activity againstM. hominisandM. fermentansand modest activity againstUreaplasmaspp.
Caspofungin in Combination with Amphotericin B against
Candida glabrata
Authors: Barchiesi Francesco , Spreghini Elisabetta , Fothergill Annette W. , Arzeni Daniela , Greganti Gianfranco , Giannini Daniele , Rinaldi Michael G. , Scalise Giorgio
Published: May 2005

The effects of caspofungin combined with amphotericin B were investigated with
Candida glabrata
. Although in vitro experiments showed an indifferent interaction, the combination regimen was the only therapeutic approach yielding organ sterilization in a murine candidemia model.
Utilization of Target-Specific, Hypersensitive Strains of
Saccharomyces cerevisiae
To Determine the Mode of Action of Antifungal Compounds
Authors: Buurman Ed T. , Andrews Beth , Blodgett April E. , Chavda Jini S. , Schnell Norbert F.
Published: May 2005

Target-specific hypersusceptible strains of
Saccharomyces cerevisiae
were used to screen antifungal compounds. Two novel Erg7p inhibitors were identified, providing proof of principle of the approach taken. However, observed hypersensitivities to antifungals acting via other targets imply that use of this tool to identify the mode of action requires significant deconvolution.
Chromosome-Borne Class A BOR-1 β
-
Lactamase of
Bordetella bronchiseptica
and
Bordetella parapertussis
Authors: Lartigue Marie-Frédérique , Poirel Laurent , Fortineau Nicolas , Nordmann Patrice
Published: May 2005

A narrow-spectrum clavulanic acid-inhibited class A β-lactamase, BOR-1, was identified in a
Bordetella bronchiseptica
clinical isolate. It shared 45% amino acid identity with L-2 from
Stenotrophomonas maltophilia
. An identical β-lactamase gene was found in
B. bronchiseptica
and
Bordetella parapertussis
reference strains that may contribute only in part to their resistance phenotype.
Identification of CTX-M-14 β-Lactamase in a
Salmonella enterica
Serovar Enteritidis Isolate from Japan
Authors: Izumiya Hidemasa , Mori Kadumi , Higashide Masato , Tamura Kazumichi , Takai Nobuko , Hirose Kenji , Terajima Jun , Watanabe Haruo
Published: May 2005

We analyzed the resistance to cefotaxime of a
Salmonella enterica
serovar Enteritidis isolate from a stool culture of a 4-year-old boy. It produced a β-lactamase CTX-M-14, encoded by two related R plasmids. The region surrounding the
bla
CTX-M-14
gene had an original mosaic structure containing insertion sequences (IS
26
and IS
903D
).
Markers of apoptosis in stage IB squamous cervical carcinoma
Authors: Van de Putte G , Holm R , Lie A K , Baekelandt M , Kristensen G B
Published: May 2005

Aims:To examine the prognostic relevance of the expression of the Bcl-2, Bcl-xL, and Bax proteins in stage IB squamous cervical carcinoma (SCC).

Methods:In total, 220 patients who underwent radical hysterectomy and bilateral lymphadenectomy at the Norwegian Radium Hospital for stage IB SCC between 1987 and 1993 were studied. Immunohistochemistry using monoclonal antibodies against Bcl-2, Bcl-xL, and Bax was used to examine protein expression. Ten patients who underwent hysterectomy for uterine prolapse served as controls.

Results:Cytoplasmic expression of Bcl-2, Bcl-xL, and Bax was low (< 5% positive cells) in 159 of 220 (73%), 193 of 220 (87%), and 39 of 220 (18%) tumours, respectively, and high (⩾ 5% positive cells) in 61 of 220 (27%), 27 of 220 (13%), and 181 of 220 (82%) tumours, respectively. In univariate analysis, all classic clinicopathological parameters but none of the investigated proteins were associated with prognosis. In multivariate analysis, only deep stromal invasion was independently related to survival.

Conclusion:Bcl-2, Bcl-xL, and Bax were not independently associated with prognosis in stage IB SCC.
Squamous cell carcinoma arising in a tall cell papillary carcinoma of the thyroid
Authors: Sutak J , Armstrong J S , Rusby J E
Published: May 2005

Transformation of differentiated thyroid cancer into poorly differentiated carcinoma is rare. This report describes a case in which preoperative fine needle aspiration suggested a squamous cell carcinoma whereas needle core biopsy favoured an undifferentiated carcinoma of probable thyroid origin. Histology of the subsequent total thyroidectomy specimen revealed a biphasic tumour comprising areas of tall cell papillary carcinoma merging with moderately to poorly differentiated squamous cell carcinoma. The immunohistochemical findings are discussed in detail.
The location of KIT and PDGFRA gene mutations in gastrointestinal stromal tumours is site and phenotype associated
Authors: Penzel R , Aulmann S , Moock M , Schwarzbach M , Rieker R J , Mechtersheimer G
Published: May 2005

Aims:To assess the relation between KIT and PDGFRA mutations and the site of origin, histological phenotype, and pathomorphologically determined risk assessment in gastrointestinal stromal tumours (GISTs).

Methods:A series of 83 clinicopathologically characterised GISTs from 79 patients was analysed for KIT and PDGFRA mutations by polymerase chain reaction amplification, single strand conformation polymorphism analysis, and direct DNA sequencing.

Results:KIT or PDGFRA mutations were found in 57 and 11 GISTs, respectively. Most KIT mutations involved exon 11 (46 cases), followed by exon 9 (10 cases). The PDGFRA mutations mostly affected exon 18 (eight cases), followed by exon 12 (three cases). There was a significant association between KIT exon 9 mutations and an intestinal origin of GISTs, and between PDGFRA mutations and gastric origin of the tumours. In addition, the presence of PDGFRA mutations was significantly associated with epithelioid/mixed histology, as was the absence of identified receptor tyrosine kinase mutations. Vice versa, KIT exon 11 mutations were almost exclusively found in spindle cell GISTs. Furthermore, the presence of any KIT and PDGFRA mutations and the presence of KIT mutations alone were significantly associated with high risk/malignant GISTs.

Conclusions:The location of KIT and PDGFRA mutations in GISTs is associated with the site of origin and histological phenotype. Genotyping of GISTs may be a helpful additional parameter in determining the biological profile of these tumours.
Mucosal integrity and barrier function in the pathogenesis of early lesions in Crohn’s disease: Figure 1
Authors: Sanders D S A
Published: May 2005

Crohn’s disease aetiology is multifactorial and remains enigmatic. However, animal models show that disease heterogeneity is probable, in that more than one defective mucosal mechanism can produce the same clinical phenotype. For example, Crohn’s-like lesions are reported after compromise of mucosal integrity per se in the presence of an intact immune system, through altered expression of mucosal adhesion molecules, such as cadherins and tight junction proteins, highlighting the importance of the mucosal barrier in the disease process. Key to mucosal damage is the trigger of an inflammatory cascade after luminal antigen processing, a role classically ascribed to M cells in the surface follicle associated epithelium. Direct luminal antigen sampling has recently been proposed, however, by extension of dendritic cell (DC) processes through the intact gut epithelium, and it follows that early mucosal damage could result from de novo lymphoid recruitment. Cytokines, such as tumour necrosis factor α (TNFα), are known to drive inflammation, but emerging data suggest additional important roles for TNFα influencing mucosal barrier efficacy by altering adhesion molecule expression, influencing epithelial apoptosis, and affecting tight junction functionality.
Gastric ciliated metaplasia. A study of 3406 gastrectomy specimens from dwellers of the Atlantic and the Pacific basins
Authors: Rubio C A , Nesi G , Zampi G C , de Ruiz P A , Jessurun J , Jónasson J , Hojman R , Kogan Z , Antonioli D , Miller M L , Hirota T , Itabashi T , Mandai K , Kitagawa T , Sugano H , Kato Y , King A , Pisano R , Owen D
Published: May 2005

Background:Ciliated cells in gastrectomies from patients dwelling in the Pacific and Atlantic basins have been reported previously.

Aim:To compare all the results in an attempt to explain the findings.

Methods:Sections from 3406 gastrectomies were reviewed: 1966 and 1440 from the Atlantic and Pacific basins, respectively. Ciliated cells and intestinal metaplasia (IM) were recorded; IM was classified into focal or extensive IM. The total number of sections/gastrectomy was noted.

Results:In the Atlantic basin, 5% of specimens had ciliated metaplasia (CM); it was more frequent in intestinal carcinoma (IC; 9%) than diffuse carcinoma (DC; 3%) or miscellaneous gastric diseases (MGD; 3%). In the Pacific basin, the frequency of specimens with CM was 29%: it was more frequent in IC (43%) than in DC (16%) or MGD (10%). The difference between the frequency of CM in specimens with IC or with DC/MGD in the Atlantic and the Pacific basins was significant (p ⩽ 0.05). The presence of CM was influenced by age and the extent of IM in both basins, but not by sex or the number of sections investigated.

Conclusions:CM—apparently an independent microscopic marker—was significantly higher in the Pacific than in the Atlantic basin. Environmental carcinogens involved in the evolution of IM and IC seem to be implicated in gastric ciliogenesis. Carcinogens that differ in nature and/or in strength in both basins might activate the latent natural genes encoding ciliated processes in gastric cells in patients subsequently developing gastric carcinoma, more notably of intestinal type.
Expression of insulin receptor substrate 1 in primary breast cancer and lymph node metastases
Authors: Koda M , Sulkowska M , Kanczuga-Koda L , Sulkowski S
Published: May 2005

Background:Insulin receptor substrate 1 (IRS-1) transmits signals from the insulin-like growth factor I receptor (IGF-IR) and insulin receptor (IR) and has been associated with the pathogenesis of cancer. IRS-1 downregulation has been suggested to play a role in breast cancer progression, but no simultaneous assessments of IRS-1 expression in primary breast cancer and metastases have been performed.

Aims:To assess IRS-1 expression in primary and metastatic breast cancer.

Methods:IRS-1 expression was analysed by means of immunohistochemistry in 109 samples of primary breast cancer and in 42 matched primary and metastatic tumours. In addition, IRS-1 expression was correlated with selected clinicopathological features, including oestrogen receptor α (ERα) and proliferation marker Ki-67 status.

Results:Positive cytoplasmic IRS-1 immunostaining was found in 69.7% (76 of 109) and 76.2% (32 of 42) of the primary and metastatic tumours, respectively. Both IRS-1 positive and IRS-1 negative primary tumours produced IRS-1 positive and IRS-1 negative metastases. IRS-1 expression in primary tumours correlated with poorly differentiated (G3) breast cancer (p<0.005) and with lymph node involvement (p<0.05). In the subgroup of ERα positive primary tumours, IRS-1 expression positively correlated with Ki-67 (p<0.02,r = 0.351), but in the subgroup of ERα negative primary tumours there was a negative correlation (p<0.03,r = −0.509). IRS-1 expression in lymph node metastases correlated with neither ERα nor Ki-67.

Conclusions:IRS-1 might be involved in breast cancer progression. Knowledge about differences between primary and metastatic tumours might help to understand mechanisms of breast cancer progression and lead to the development of more effective anticancer drugs.
The p53–Mdm2 association in epithelial cells in idiopathic pulmonary fibrosis and non-specific interstitial pneumonia
Authors: Nakashima N , Kuwano K , Maeyama T , Hagimoto N , Yoshimi M , Hamada N , Yamada M , Nakanishi Y
Published: May 2005

Background:Wild-type p53 is increased during cellular responses to various stresses. Mdm2, which is induced by p53, regulates p53 protein concentrations through the ubiquitin–proteasome pathway.

Aim:To investigate whether the Mdm2 mediated ubiquitination of p53 is associated with epithelial cell apoptosis in idiopathic pulmonary fibrosis (IPF).

Methods:Immunohistochemistry and western blot analysis were carried out on lung samples obtained by lung biopsy from patients with IPF and non-specific interstitial pneumonia (NSIP).

Results:The expression of p53, phosphorylated p53, Mdm2, p21, and Bax was upregulated in epithelial cells from patients with IPF and NSIP compared with normal lung parenchyma. Except for p21, there was a significant increase in the expression of these factors in IPF compared with NSIP. In addition, the number of apoptotic cells and the number of p53 and Bax positive cells was increased compared with controls. p53 conjugated with Mdm2 was decreased in IPF compared with NSIP and controls. Ubiquitinated p53 was increased in both IPF and NSIP compared with controls.

Conclusions:Signalling molecules associated with p53 mediated apoptosis may participate in epithelial cell apoptosis, and the attenuation of p53–Mdm2 conjugation and of p53 degradation may be involved in the epithelial cell apoptosis seen in IPF. Augmented epithelial apoptosis in IPF may lead to the poor prognosis compared with NSIP.
Stromal nitric oxide synthase (NOS) expression correlates with the grade of mammary phyllodes tumour
Authors: Tse G M K , Wong F C , Tsang A K H , Lee C S , Lui P C W , Lo A W I , Law B K B , Scolyer R A , Karim R Z , Putti T C
Published: May 2005

Background:Nitric oxide synthase (NOS), particularly endothelial and inducible forms (e/i-NOS), are expressed in various cancers, including breast cancer. In mammary fibroepithelial lesions, NOS expression in stromal cells has been reported to be lower in fibroadenomas than in phyllodes tumours.

Aims:To investigate NOS expression in phyllodes tumours of varying degrees of malignancy.

Methods:One hundred and sixty seven mammary phyllodes tumours (97 benign, 47 borderline malignant, and 23 frankly malignant) were evaluated for e-NOS and i-NOS expression by immunohistochemistry. Correlations with previously reported expression of stromal vascular growth factor (VEGF) and microvessel density were also performed.

Results:Stromal expression of e-NOS was absent, weak, moderate, and strong in 43%, 31%, 13%, and 13% of benign tumours; 17%, 26%, 13%, and 44% of borderline malignant tumours; and 17%, 35%, 13%, and 35% of frankly malignant tumours, respectively. Stromal expression of i-NOS was 77%, 18%, 4%, and 1% in benign tumours; 42%, 28%, 19%, and 11% in borderline malignant tumours; and 43%, 13%, 26%, and 18% in frankly malignant tumours, respectively. Stromal expression of both i-NOS and e-NOS was significantly different between the benign and malignant (borderline and frank) groups of phyllodes tumours (p<0.0001). Furthermore, the expression of i-NOS correlated with stromal VEGF expression and microvessel density. The expression of NOS in the epithelial cells was strong, and showed no differences between the different groups of tumours.

Conclusions:Higher stromal expression of NOS in phyllodes tumours is associated with malignancy, suggesting a possible role in malignant progression, particularly metastasising potential.
Di-George syndrome presenting with hypocalcaemia in adulthood: two case reports and a review
Authors: Kar P S , Ogoe B , Poole R , Meeking D
Published: May 2005

This report describes two cases of Di-George syndrome presenting with hypoparathyroidism in adulthood. The first patient presented with profound hypocalcaemia that resulted in a generalised seizure. Routine investigations revealed hypoparathyroidism. The clue to her underlying condition was the postnatal death of her young child. This case shows that Di-George syndrome can present in adulthood with hypocalcaemia in the absence of other classic features of this condition. This has enormous implications for future family planning and may also have important health implications. The second patient, diagnosed on routine blood testing, had previously suffered with a congenital heart condition, but the syndrome was not revealed until she was of postmenopausal age. These two patients show that Di-George syndrome can present in adulthood with hypocalcaemia. This is an important observation because the condition has profound implications for health and family planning.