bluuebunny/crossref_metadata_2025 huggingface dataset:
Postsynaptic Glutamate Transport at the Climbing Fiber-Purkinje Cell Synapse
Authors: Otis Thomas S. , Kavanaugh Michael P. , Jahr Craig E.
Published: July 2002

The role of postsynaptic, neuronal glutamate transporters in terminating signals at central excitatory synapses is not known. Stimulation of a climbing fiber input to cerebellar Purkinje cells was shown to generate an anionic current mediated by glutamate transporters. The kinetics of transporter currents were resolved by pulses of glutamate to outside-out membrane patches from Purkinje cells. Comparison of synaptic transporter currents to transporter currents expressed in
Xenopus
oocytes suggests that postsynaptic uptake at the climbing fiber synapse removes at least 22 percent of released glutamate. These neuronal transporter currents arise from synchronous activation of transporters that greatly outnumber activated AMPA receptors.
Generation of Intestinal T Cells from Progenitors Residing in Gut Cryptopatches
Authors: Saito Hisashi , Kanamori Yutaka , Takemori Toshitada , Nariuchi Hideo , Kubota Eiro , Takahashi-Iwanaga Hiromi , Iwanaga Toshihiko , Ishikawa Hiromichi
Published: July 2002

Cryptopatches (CPs) are part of the murine intestinal immune compartment. Cells isolated from CPs of the small intestine that were c-kit positive (c-kit
+
) but lineage markers negative (Lin
−
) gave rise to T cell receptor (TCR) αβ and TCR γδ intestinal intraepithelial T cells after in vivo transfer or tissue engraftment into severe combined immunodeficient mice. In contrast, cells from Peyer's patches and mesenteric lymph nodes, which belong in the same intestinal immune compartment but lack c-kit
+
Lin
−
cells, failed to do so. These findings and results of electron microscopic analysis provide evidence of a local intestinal T cell precursor that develops in the CPs.
Callosal Window Between Prefrontal Cortices: Cognitive Interaction to Retrieve Long-Term Memory
Authors: Hasegawa Isao , Fukushima Tetsuya , Ihara Takeshi , Miyashita Yasushi
Published: July 2002

A perceptual image can be recalled from memory without sensory stimulation. However, the neural origin of memory retrieval remains unsettled. To examine whether memory retrieval can be regulated by top-down processes originating from the prefrontal cortex, a visual associative memory task was introduced into the partial split-brain paradigm in monkeys. Long-term memory acquired through stimulus-stimulus association did not transfer via the anterior corpus callosum, a key part interconnecting prefrontal cortices. Nonetheless, when a visual cue was presented to one hemisphere, the anterior callosum could instruct the other hemisphere to retrieve the correct stimulus specified by the cue. Thus, although visual long-term memory is stored in the temporal cortex, memory retrieval is under the executive control of the prefrontal cortex.
Discovery of a Low-Mass Brown Dwarf Companion of the Young Nearby Star G 196-3
Authors: Rebolo Rafael , Osorio Marı́a R. Zapatero , Madruga Santiago , Béjar Vı́ctor J. S. , Arribas Santiago , Licandro Javier
Published: July 2002

A substellar-mass object in orbit at about 300 astronomical units from the young low-mass star G 196-3 was detected by direct imaging. Optical and infrared photometry and low- and intermediate-resolution spectroscopy of the faint companion, hereafter referred to as G 196-3B, confirm its cool atmosphere and allow its mass to be estimated at 25
−10
+15
Jupiter masses. The separation between the objects and their mass ratio suggest the fragmentation of a collapsing cloud as the most likely origin for G 196-3B, but alternatively it could have originated from a protoplanetary disc that has been dissipated. Whatever the formation process was, the young age of the primary star (about 100 million years) demonstrates that substellar companions can form on short time scales.
Long-Term Discrepancy Between Food Supply and Demand in the Deep Eastern North Pacific
Authors: Smith Kenneth L. , Kaufmann Ronald S.
Published: July 2002

A 7-year study of food supply [sinking particulate organic carbon (POC)] and food demand [sediment community oxygen consumption (SCOC)] in the abyssal eastern North Pacific revealed a long-term deficit in food supply. The POC:SCOC ratio decreased by 52 to 59 percent between 1989 and 1996. A possible explanation for this trend is the documented sea surface temperature increase and concomitant plankton biomass decrease in the eastern North Pacific, resulting in an apparent reduction in POC export from surface waters to the deep ocean. Continuation of this trend could profoundly impact geochemical cycling as well as the structure and dynamics of deep-sea communities.
hRAD30
Mutations in the Variant Form of Xeroderma Pigmentosum
Authors: Johnson Robert E. , Kondratick Christine M. , Prakash Satya , Prakash Louise
Published: July 2002

Xeroderma pigmentosum (XP) is an autosomal recessive disease characterized by a high incidence of skin cancers. Yeast
RAD30
encodes a DNA polymerase involved in the error-free bypass of ultraviolet (UV) damage. Here it is shown that XP variant (XP-V) cell lines harbor nonsense or frameshift mutations in
hRAD30
, the human counterpart of yeast
RAD30
. Of the eight mutations identified, seven would result in a severely truncated hRad30 protein. These results indicate that defects in
hRAD30
cause XP-V, and they suggest that error-free replication of UV lesions by hRad30 plays an important role in minimizing the incidence of sunlight-induced skin cancers.
Crystal Structure of Invasin: A Bacterial Integrin-Binding Protein
Authors: Hamburger Zsuzsa A. , Brown Michele S. , Isberg Ralph R. , Bjorkman Pamela J.
Published: July 2002

The
Yersinia pseudotuberculosis
invasin protein promotes bacterial entry by binding to host cell integrins with higher affinity than natural substrates such as fibronectin. The 2.3 angstrom crystal structure of the invasin extracellular region reveals five domains that form a 180 angstrom rod with structural similarities to tandem fibronectin type III domains. The integrin-binding surfaces of invasin and fibronectin include similarly located key residues, but in the context of different folds and surface shapes. The structures of invasin and fibronectin provide an example of convergent evolution, in which invasin presents an optimized surface for integrin binding, in comparison with host substrates.
Modulation of Hurricane Activity in the Gulf of Mexico by the Madden-Julian Oscillation
Authors: Maloney Eric D. , Hartmann Dennis L.
Published: July 2002

The Madden-Julian oscillation (MJO) is a large-scale episodic modulation of tropical winds and precipitation that travels eastward from Asia to America, with a characteristic repeat time of 30 to 60 days. Here it is shown that when MJO wind anomalies in the lower troposphere of the eastern Pacific are westerly, Gulf of Mexico and western Caribbean hurricane genesis is four times more likely than when the MJO winds are easterly. Accurate predictions of the MJO may lead to improved long-range forecasts of tropical cyclone activity.
Genetic Requirements for Inheritance of RNAi in
C. elegans
Authors: Grishok Alla , Tabara Hiroaki , Mello Craig C.
Published: July 2002

In
Caenorhabditis elegans
, the introduction of double-stranded RNA triggers sequence-specific genetic interference (RNAi) that is transmitted to offspring. The inheritance properties associated with this phenomenon were examined. Transmission of the interference effect occurred through a dominant extragenic agent. The wild-type activities of the RNAi pathway genes
rde-1
and
rde-4
were required for the formation of this interfering agent but were not needed for interference thereafter. In contrast, the
rde-2
and
mut-7
genes were required downstream for interference. These findings provide evidence for germ line transmission of an extragenic sequence-specific silencing factor and implicate
rde-1
and
rde-4
in the formation of the inherited agent.
Low (Sub-1-Volt) Halfwave Voltage Polymeric Electro-optic Modulators Achieved by Controlling Chromophore Shape
Authors: Shi Yongqiang , Zhang Cheng , Zhang Hua , Bechtel James H. , Dalton Larry R. , Robinson Bruce H. , Steier William H.
Published: July 2002

Electro-optic (EO) modulators encode electrical signals onto fiber optic transmissions. High drive voltages limit gain and noise levels. Typical polymeric and lithium niobate modulators operate with halfwave voltages of 5 volts. Sterically modified organic chromophores have been used to reduce the attenuation of electric field poling–induced electro-optic activity caused by strong intermolecular electrostatic interactions. Such modified chromophores, incorporated into polymer hosts, were used to fabricate EO modulators with halfwave voltages of 0.8 volts (at a telecommunications wavelength of 1318 nanometers) and to achieve a halfwave voltage-interaction length product of 2.2 volt-centimeters. Optical push-pull poling and driving were also used to reduce halfwave voltage. This study, together with recent demonstrations of exceptional bandwidths (more than 110 gigahertz) and ease of integration (with very large scale integration semiconductor circuitry and ultra-low-loss passive optical circuitry) demonstrates the potential of polymeric materials for next generation telecommunications, information processing, and radio frequency distribution.
Atomically Resolved Single-Walled Carbon Nanotube Intramolecular Junctions
Authors: Ouyang Min , Huang Jin-Lin , Cheung Chin Li , Lieber Charles M.
Published: July 2002

Intramolecular junctions in single-walled carbon nanotubes are potentially ideal structures for building robust, molecular-scale electronics but have only been studied theoretically at the atomic level. Scanning tunneling microscopy was used to determine the atomic structure and electronic properties of such junctions in single-walled nanotube samples. Metal-semiconductor junctions are found to exhibit an electronically sharp interface without localized junction states, whereas a more diffuse interface and low-energy states are found in metal-metal junctions. Tight-binding calculations for models based on observed atomic structures show good agreement with spectroscopy and provide insight into the topological defects forming intramolecular junctions. These studies have important implications for applications of present materials and provide a means for assessing efforts designed to tailor intramolecular junctions for nanoelectronics.
Generation of an LFA-1 Antagonist by the Transfer of the ICAM-1 Immunoregulatory Epitope to a Small Molecule
Authors: Gadek T. R. , Burdick D. J. , McDowell R. S. , Stanley M. S. , Marsters J. C. , Paris K. J. , Oare D. A. , Reynolds M. E. , Ladner C. , Zioncheck K. A. , Lee W. P. , Gribling P. , Dennis M. S. , Skelton N. J. , Tumas D. B. , Clark K. R. , Keating S. M. , Beresini M. H. , Tilley J. W. , Presta L. G. , Bodary S. C.
Published: July 2002

The protein-protein interaction between leukocyte functional antigen–1 (LFA-1) and intercellular adhesion molecule–1 (ICAM-1) is critical to lymphocyte and immune system function. Here, we report on the transfer of the contiguous, nonlinear epitope of ICAM-1, responsible for its association with LFA-1, to a small-molecule framework. These LFA-1 antagonists bound LFA-1, blocked binding of ICAM-1, and inhibited a mixed lymphocyte reaction (MLR) with potency significantly greater than that of cyclosporine A. Furthermore, in comparison to an antibody to LFA-1, they exhibited significant anti-inflammatory effects in vivo. These results demonstrate the utility of small-molecule mimics of nonlinear protein epitopes and the protein epitopes themselves as leads in the identification of novel pharmaceutical agents.
In Vitro Activity of the New Triazole BMS-207147 against
Aspergillus
Species in Comparison with Itraconazole and Amphotericin B
Authors: Moore Caroline B. , Walls Caroline M. , Denning David W.
Published: July 2002

The in vitro activity of BMS-207147 against 80 clinical isolates of
Aspergillus
was compared with that of itraconazole and amphotericin B, using a validated microtiter method. Geometric mean MICs (in μg/ml) were as follows: 1.71 for BMS-207147, 0.67 for itraconazole, and 0.63 for amphotericin B. The range of concentrations of each drug was 0.125 to >16 μg/ml.
Aspergillus fumigatus
was significantly more susceptible to BMS-207147 (
P
 < 0.05) than
A. terreus
and
A. flavus
. No BMS-207147-resistant
A. fumigatus
isolates were identified, though eight itraconazole-resistant (MIC, >8 μg/ml) isolates were. BMS-207147 is active against
Aspergillus
spp. at slightly high concentrations compared with itraconazole and amphotericin B.
Apoptosis in Renal Proximal Tubules of Rats Treated with Low Doses of Aminoglycosides
Authors: El Mouedden Mohammed , Laurent Guy , Mingeot-Leclercq Marie-Paule , Taper Henryk S. , Cumps Jean , Tulkens Paul M.
Published: July 2002

Kidney cortex apoptosis was studied with female Wistar rats treated for 10 days with gentamicin and netilmicin at daily doses of 10 or 20 mg/kg of body weight and amikacin or isepamicin at daily doses of 40 mg/kg. Apoptosis was detected and quantitated using cytological (methyl green-pyronine) and immunohistochemical (terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling) staining, in parallel with a measurement of drug-induced phospholipidosis (cortical phospholipids and phospholipiduria), cortical proliferative response (3H incorporation in DNA and histoautoradiography after in vivo pulse-labeling with [3H]thymidine), and kidney dysfunction (blood urea nitrogen and creatinine). Gentamicin induced in proximal tubules a marked apoptotic reaction which (i) was detectable after 4 days of treatment but was most conspicuous after 10 days, (ii) was dose dependent, (iii) occurred in the absence of necrosis, and (iv) was nonlinearly correlated with the proliferative response (tubular and peritubular cells). Comparative studies revealed a parallelism among the extents of phospholipidosis, apoptosis, and proliferative response for three aminoglycosides (gentamicin >> amikacin ≅ isepamicin). By contrast, netilmicin induced a marked phospholipidosis but a moderate apoptosis and proliferative response. We conclude that rats treated with gentamicin develop an apoptotic process as part of the various cortical alterations induced by this antibiotic at low doses. Netilmicin, and still more amikacin and isepamicin, appears safer in this respect. Whereas a relation between aminoglycoside-induced tubular apoptosis and cortical proliferative response seems to be established, no simple correlation with phospholipidosis can be drawn.
Pharmacologic Characteristics of Indinavir, Didanosine, and Stavudine in Human Immunodeficiency Virus-Infected Children Receiving Combination Therapy
Authors: Fletcher Courtney V. , Brundage Richard C. , Remmel Rory P. , Page Linda M. , Weller Dennis , Calles Nancy R. , Simon Cara , Kline Mark W.
Published: July 2002

The use of human immunodeficiency virus (HIV) protease inhibitors in children has lagged behind that in adults because of the lack of suitable pediatric formulations and information on safe and effective dosing regimens. This study was designed to obtain pharmacokinetic information on indinavir, administered to HIV-infected children also receiving therapy with two nucleoside agents, and to explore relationships between pharmacokinetic parameters and anti-HIV effect. Indinavir was initiated at a dose of 500 mg/m
2
every 8 h. Plasma indinavir concentrations were measured every 4 weeks; the dose or dosing interval was adjusted to maintain trough concentrations of ≥0.1 mg/liter. All children were evaluated clinically at baseline and every 4 weeks. Plasma HIV RNA was quantitated at baseline and at weeks 4, 12, and 24. Eighteen children participated in this study. The average daily dose of indinavir was 2,043 mg/m
2
; nine children received indinavir at 6-h intervals. Pharmacokinetic characteristics of indinavir (mean ± standard deviation) were the following: oral clearance, 1.4 ± 0.5 liters/h/kg; half-life, 1.1 ± 0.43 h; and trough concentration, 0.29 ± 0.32 mg/liter. In nine children that completed 24 weeks of therapy, the baseline-to-week-24 change in HIV RNA level was related to indinavir trough concentration and didanosine area under the curve. This study illustrates the ability to obtain pharmacokinetic information from children during routine clinic visits and to use this information to provide a safeguard against underdosing. The incorporation of pharmacologic knowledge with virologic, immunologic, and behavioral considerations should result in improved clinical outcomes for children infected with HIV.
Pharmacokinetics of Single-Dose Oral Stavudine in Subjects with Renal Impairment and in Subjects Requiring Hemodialysis
Authors: Grasela Dennis M. , Stoltz Randall R. , Barry Michael , Bone Michael , Mangold Bernhard , O'Grady Padraig , Raymond Ralph , Haworth Stephen J.
Published: July 2002

Two open-label studies assessed the pharmacokinetics of single orally administered doses of 40 mg of stavudine in subjects with renal impairment. In one study (study I), 15 subjects with selected degrees of renal impairment, but not requiring hemodialysis, were stratified into three groups of five subjects each according to creatinine clearance (CL
CR
) normalized by body surface area (ml/min/1.73 m
2
): mild (CL
CR
, 60 to 80), moderate (30 to 50), and severe (≤20) renal impairment. Five healthy subjects (CL
CR
≥ 90) were also enrolled. The stavudine area under the curve from 0 h to infinity (AUC
0–∞
) increased nonlinearly with declining renal function: 1,864, 2,215, 3,609, and 5,928 ng · h/ml for normal renal function and for mild, moderate, and severe renal impairment, respectively (
P
= 0.0001 between renal impairment groups). The following stavudine dosage recommendations for renal impairment were proposed for subjects weighing ≥60 kg: CL
CR
of >50 ml/min/1.73 m
2
, 40 mg every 12 h; CL
CR
of 21 to 50 ml/min/1.73 m
2
, 20 mg every 12 h; and CL
CR
of 10 to 20 ml/min/1.73 m
2
, 20 mg every 24 h. For subjects weighing <60 kg, the proposed doses were 30, 15, and 15 mg, respectively, with the same dosing intervals specified above. In a second study (study II), 12 subjects with end-stage renal disease requiring hemodialysis three times a week were enrolled in a randomized, open-label crossover study (dialysis 2 h after dosing and lasting 4 h or dosing without dialysis). There were no statistically significant differences for AUC
0–∞
, AUC
2–6
, time to maximum concentration of drug in serum, half-life, or apparent oral clearance when the two treatment dosage regimens were compared. As a result of study II, the recommended dosing rate for subjects requiring hemodialysis was the same as that proposed for those with severe renal impairment not requiring hemodialysis; however, dosing was recommended to follow hemodialysis and to occur at the same time each day.
If Taken 1 Hour before Indinavir (IDV), Didanosine Does Not Affect IDV Exposure, despite Persistent Buffering Effects
Authors: Shelton Mark J. , Mei Haijing , Hewitt Ross G. , Defrancesco Robin
Published: July 2002

Concurrent administration of indinavir and didanosine significantly reduces the level of exposure to indinavir, but it is unclear how soon after didanosine administration indinavir may be given safely. We compared indinavir pharmacokinetics and gastric pH in 12 human immunodeficiency virus-positive patients by use of 800 mg of indinavir alone versus 800 mg of indinavir administered 1 h after didanosine administration. Median gastric pH was significantly higher when indinavir was taken after didanosine administration; however, no significant difference in the maximum concentration in plasma or the area under the concentration-time curve from time zero to 8 h was observed. Indinavir may be taken with a light meal 1 h following the administration of 400 mg of didanosine.
Efficacy of 2-Amino-7-(1,3-Dihydroxy-2-Propoxymethyl)Purine for Treatment of Vaccinia Virus (Orthopoxvirus) Infections in Mice
Authors: Neyts Johan , De Clercq Erik
Published: July 2002

We have previously shown that the N-7 substituted acyclic nucleoside analog 2-amino-7-[1,3-dihydroxy-2-propoxy)methyl]purine (compound S2242) is, both in vitro and in animal models, a potent inhibitor of the replication of several herpesviruses (Neyts et al., Antimicrob. Agents Chemother. 39:56–60, 1995). Here we report on the potent and selective antiviral activity of S2242 against vaccinia virus (VV), an orthopoxvirus. The 50% effective concentrations for inhibition of VV-induced cytopathic effect and viral DNA synthesis in cell culture were 2.4 and 0.2 μg/ml, respectively. We next studied the efficacy of S2242 in VV-infected mice. Immunocompetent NMRI mice that had been inoculated intravenously with VV developed tail lesions. Mice that had been treated for 5 consecutive days via the subcutaneous (s.c.) route with 100 mg of the diacetate ester prodrug of S2242 (compound H961) per kg of body weight did not develop any lesions and demonstrated no adverse effects. Severe combined immunodeficient (SCID) mice that had been inoculated intraperitoneally with VV became sick and died within 1 month after infection. Following treatment with H961 at 100 mg/kg for 10 consecutive days (either via oral gavage or s.c. injection) VV-inoculated SCID mice were completely protected, for at least 3 months, against virus-induced morbidity and mortality. At that time, no virus could be recovered from the organs of these mice (as assessed by titration for infectious virus, a DNA hybridization assay, and a PCR for VV-specific sequences). Compound S2242 and its oral prodrug H961 could be useful in treatment of orthopoxvirus infections.
Bronchopulmonary Disposition of the Ketolide Telithromycin (HMR 3647)
Authors: Muller-Serieys Claudette , Soler Paul , Cantalloube Cathy , Lemaitre Françoise , Gia Hai Pham , Brunner Françoise , Andremont Antoine
Published: July 2002

Telithromycin (HMR 3647) is the first member of a new family of antimicrobials, the ketolides, developed specifically for the treatment of community-acquired respiratory tract infections. Telithromycin has proven in vitro activity against both common and atypical respiratory tract pathogens. The penetration of telithromycin into bronchopulmonary tissues and subsequent elimination from these sites were evaluated in four groups (groups A, B, C, and D) of six healthy male subjects who received telithromycin at 800 mg once daily for 5 days. Subjects in groups A, B, C, and D underwent fiberoptic bronchoscopy and bronchoalveolar lavage 2, 8, 24, and 48 h after receipt of the last dose, respectively. The concentration of telithromycin in the alveolar macrophages, epithelial lining fluid (ELF), and plasma was determined by the agar diffusion method with
Bacillus subtilis
ATCC 6633 as the test organism. The concentration of telithromycin in alveolar macrophages markedly exceeded that in plasma, reaching up to 146 times the concentration in plasma 8 h after dosing (median concentration, 81 mg/liter). Telithromycin was retained in alveolar macrophages 24 h after dosing (median concentration, 23 mg/liter), and it was still quantifiable 48 h after dosing (median concentration, 2.15 mg/liter). Telithromycin median concentrations in ELF also markedly exceeded concentrations in plasma (median concentration in ELF, 3.7 mg/liter 8 h after dosing). Telithromycin achieves high and sustained concentrations in ELF and in alveolar macrophages, while it maintains adequate levels in plasma, providing an ideal pharmacokinetic profile for effective treatment of community-acquired respiratory tract infections caused by either common or atypical, including intracellular, respiratory tract pathogens.
Staphylococcus aureus
Mutants Isolated via Exposure to Nonfluorinated Quinolones: Detection of Known and Unique Mutations
Authors: Roychoudhury Siddhartha , Twinem Tracy L. , Makin Kelly M. , Nienaber Mark A. , Li Chuiying , Morris Timothy W. , Ledoussal Benoit , Catrenich Carl E.
Published: July 2002

The in vitro development of resistance to the new nonfluorinated quinolones (NFQs; PGE 9262932, PGE 4175997, and PGE 9509924) was investigated in
Staphylococcus aureus
. At concentrations two times the MIC, step 1 mutants were isolated more frequently with ciprofloxacin and trovafloxacin (9.1 × 10
−8
and 5.7 × 10
−9
, respectively) than with the NFQs, gatifloxacin, or clinafloxacin (<5.7 × 10
−10
). Step 2 and step 3 mutants were selected via exposure of a step 1 mutant (selected with trovafloxacin) to four times the MICs of trovafloxacin and PGE 9262932. The step 1 mutant contained the known Ser80-Phe mutation in GrlA, and the step 2 and step 3 mutants contained the known Ser80-Phe and Ser84-Leu mutations in GrlA and GyrA, respectively. Compared to ciprofloxacin, the NFQs were 8-fold more potent against the parent and 16- to 128-fold more potent against the step 3 mutants. Mutants with high-level NFQ resistance (MIC, 32 μg/ml) were isolated by the spiral plater-based serial passage technique. DNA sequence analysis of three such mutants revealed the following mutations: (i) Ser84-Leu in GyrA and Glu84-Lys and His103-Tyr in GrlA; (ii) Ser-84Leu in GyrA, Ser52-Arg in GrlA, and Glu472-Val in GrlB; and (iii) Ser84-Leu in GyrA, Glu477-Val in GyrB, and Glu84-Lys and His103-Tyr in GrlA. Addition of the efflux pump inhibitor reserpine (10 μg/ml) resulted in 4- to 16-fold increases in the potencies of the NFQs against these mutants, whereas it resulted in 2-fold increases in the potencies of the NFQs against the parent.
Lack of Emergence of Cytomegalovirus UL97 Mutations Conferring Ganciclovir (GCV) Resistance following Preemptive GCV Therapy in Allogeneic Stem Cell Transplant Recipients
Authors: Gilbert C. , Roy J. , Belanger R. , Delage R. , Beliveau C. , Demers C. , Boivin G.
Published: July 2002

Fifty allogeneic stem cell transplant recipients were enrolled in a prospective cytomegalovirus pp65 antigenemia-guided preemptive therapy trial. Among these, 10 of 34 patients who received ganciclovir exhibited sustained and/or recurrent antigenemia despite treatment. Thirteen leukocyte preparations from these 10 subjects were screened for the presence of the most frequent cytomegalovirus UL97 mutations conferring ganciclovir resistance. None of these mutations were detected after mean and median ganciclovir exposures of 31.6 and 28.0 days, respectively.
Comparative Antianaerobic Activity of BMS 284756
Authors: Hoellman Dianne B. , Kelly Linda M. , Jacobs Michael R. , Appelbaum Peter C.
Published: July 2002

Agar dilution MIC methodology was used to compare the activity of BMS 284756 with those of ciprofloxacin, levofloxacin, moxifloxacin, trovafloxacin, amoxicillin-clavulanate, piperacillin-tazobactam, imipenem, clindamycin, and metronidazole against 357 anaerobes. Overall, the respective MICs at which 50% of the isolates tested were inhibited (MIC
50
s) and MIC
90
s (in micrograms per milliliter) were as follows: BMS 284756, 0.5 and 2.0; ciprofloxacin, 2.0 and 16.0; levofloxacin, 1.0 and 8.0; moxifloxacin, 0.5 and 4.0; trovafloxacin, 0.5 and 2.0; amoxicillin-clavulanate, 0.5 and 2.0; piperacillin-tazobactam, 0.25 and 8.0; imipenem, 0.06 and 1.0; clindamycin, 0.25 and 8.0; and metronidazole, 1.0 and >16.0. BMS 284756 is a promising new quinolone with excellent antianaerobic activity.
Cyclopentane Neuraminidase Inhibitors with Potent In Vitro Anti-Influenza Virus Activities
Authors: Smee Donald F. , Huffman John H. , Morrison Ann C. , Barnard Dale L. , Sidwell Robert W.
Published: July 2002

A novel series of cyclopentane derivatives have been found to exhibit potent and selective inhibitory effects on influenza virus neuraminidase. These compounds, designated RWJ-270201, BCX-1827, BCX-1898, and BCX-1923, were tested in parallel with zanamivir and oseltamivir carboxylate against a spectrum of influenza A (H1N1, H3N2, and H5N1) and influenza B viruses in MDCK cells. Inhibition of viral cytopathic effect ascertained visually and by neutral red dye uptake was used, with 50% effective (virus-inhibitory) concentrations (EC
50
) determined. Against the H1N1 viruses A/Bayern/07/95, A/Beijing/262/95, A/PR/8/34, and A/Texas/36/91, EC
50
s (determined by neutral red assay) of the novel compounds were ≤1.5 μM. Twelve strains of H3N2 and two strains of avian H5N1 viruses were inhibited at <0.3 μM. Influenza B/Beijing/184/93 and B/Harbin/07/94 viruses were inhibited at <0.2 μM, with three other B virus strains inhibited at 0.8 to 8 μM. The novel inhibitors were comparable in potency to (or slightly more potent than) zanamivir and oseltamivir carboxylate. No cytotoxicity was seen with the compounds at concentrations of ≤1 mM in cell proliferation assays. The antiviral activity of RWJ-270201, chosen for clinical development, was studied in greater detail. Its potency and that of oseltamivir carboxylate decreased with increasing multiplicity of virus infection. Time-of-addition studies indicated that treatment with either compound needed to begin 0 to 12 h after virus exposure for optimal activity. Exposure of cells to RWJ-270201 caused most of the virus to remain cell associated, with extracellular virus decreasing in a concentration-dependent manner. This is consistent with its effect as a neuraminidase inhibitor. RWJ-270201 shows promise in the treatment of human influenza virus infections.
Controlled Trial of 3-Day Quinine-Clindamycin Treatment versus 7-Day Quinine Treatment for Adult Travelers with Uncomplicated Falciparum Malaria Imported from the Tropics
Authors: Parola Phillippe , Ranque Stephane , Badiaga Sekene , Niang Mohamadou , Blin Olivier , Charbit Jean-Jacques , Delmont Jean , Brouqui Philippe
Published: July 2002

We conducted a randomized, double-blind, placebo-controlled trial to compare a 3-day quinine-clindamycin regimen (group QC) with a 7-day quinine regimen (group Q) for the treatment of uncomplicated
Plasmodium falciparum
malaria in travelers returning from the tropics. A total of 55 and 53 patients in groups Q and QC were analyzed, respectively. Adverse effects were similar in both groups, although two patients in group Q had severe adverse reactions, leading to the cessation of treatment. The 28-day cure rate for the evaluated patients (per-protocol analysis) was 100% for group QC, whereas it was 96.3% for group Q (
P
= 0.5). The 28-day cure rate in the intention-to-treat analysis was 96.2% for group QC, whereas it was 94.6% for group Q (
P
= 1). There were no significant differences between the two regimens with regard to parasite and fever clearance times. Our study shows that the 3-day quinine-clindamycin regimen is well tolerated and compares favorably with a 7-day quinine treatment. This short-term regimen had previously been evaluated only in areas of endemicity. According to our results, the 3-day quinine-clindamycin regimen may be an alternative for the treatment of imported uncomplicated
P. falciparum
malaria in travelers returning from the tropics.
Activities and Conformational Fitting of 1,4-Naphthoquinone Derivatives and Other Cyclic 1,4-Diones Tested In Vitro againstPneumocystis carinii
Authors: Ball M. D. , Bartlett M. S. , Shaw M. , Smith J. W. , Nasr M. , Meshnick S. R.
Published: July 2002

Atovaquone is a chemotherapeutic agent used to treat pneumonia caused byPneumocystis cariniiin some immunocompromised patients. A set of cyclic 1,4-diones were tested in vitro for ability to inhibit growth ofP. carinii, including 22 variously substituted 1,4-naphthoquinones, one bis-1,4-naphthoquinone, and three other quinones. For comparison, the antipneumocystic primaquine and its 5-hydroxy-6-desmethyl metabolite were also tested. At 1.0 μg/ml, seven compounds inhibited growth by at least 39%, with atovaquone at 92%; of these seven, five are 2-hydroxy-1,4-naphthoquinones, while one is a 2-chloro- and another is a 2-methyl-1,4-naphthoquinone. At 0.1 μg/ml, however, the most active compound tested was the primaquine metabolite, which inhibited growth by more than 42% at this concentration. To ascertain a structure-activity relationship, all 1,4-naphthoquinones were compared conformationally by means of computer-based molecular modeling (Spartan) incorporating the Sybyl force field. Without exception, for all 21 monomers tested, the substituent at position 3 of the 1,4-naphthoquinone favored activity most strongly when it simultaneously occupied (i) space centered at about 3 Å from position 3, without projecting steric bulk from the area encompassed by atovaquone's cyclohexyl ring, and (ii) roughly planar space at about 7.3 Å from position 3, without projecting steric bulk perpendicularly. This structure-activity relationship may prove useful in the rational design of better antipneumocystis agents.
Antimicrobial Activities of BMS-284756 Compared with Those of Fluoroquinolones and β-Lactams against Gram-Positive Clinical Isolates
Authors: Bassetti Matteo , Dembry Louise M. , Farrel Patricia A. , Callan Deborah A. , Andriole Vincent T.
Published: July 2002

The in vitro antibacterial activity of BMS-284756 was compared to those of ciprofloxacin, gatifloxacin, moxifloxacin, ceftriaxone, imipenem, piperacillin-tazobactam, and amoxicillin-clavulanic acid against 492 gram-positive clinical isolates. BMS-284756 was the most-active agent against
Streptococcus pneumoniae
,
Streptococcus viridans
, beta-hemolytic streptococci, methicillin-sensitive and -resistant
Staphylococcus aureus
, methicillin-sensitive and -resistant coagulase-negative staphylococci, and enterococci.
Use of Terbinafine in Mouse and Rat Models ofPneumocystis cariniiPneumonia
Authors: Walzer Peter D. , Ashbaugh Alan
Published: July 2002

Terbinafine, an allylamine used to treat onychomycosis, has been reported to be active against ratPneumocystis cariniiin vitro and in vivo. By contrast, our in vitro data showed that the 50% inhibitory concentration of terbinafine against ratP. cariniiis 3.7 μg/ml, a level that cannot be clinically achieved in serum. In the present study, terbinafine administered orally at doses of 20 to 400 mg/kg/day and 50 to 250 mg/kg/day was ineffective therapy for mouse and rat models of pneumocystosis, respectively. These results emphasize the complexities ofP. cariniidrug testing and the need for caution before considering studies in humans.
Integron-Locatedoxa-32Gene Cassette Encoding an Extended-Spectrum Variant of OXA-2 β-Lactamase fromPseudomonas aeruginosa
Authors: Poirel Laurent , Gerome Patrick , De Champs Christophe , Stephanazzi Jean , Naas Thierry , Nordmann Patrice
Published: July 2002

Pseudomonas aeruginosaclinical isolate CY-1, which was resistant to ceftazidime, harbored a conjugative ca. 250-kb plasmid that contained a class 1 integron with two gene cassettes encoding OXA-32, an OXA-2- type β-lactamase, and the aminoglycoside acetyltransferase AAC(6′)Ib9. OXA-32 differed from OXA-2 by an Leu169Ile amino acid substitution (class D numbering). Site-directed mutagenesis established that Ile169 is responsible for resistance to ceftazidime but not to cefotaxime.
Comparison of Oral Artesunate and Dihydroartemisinin Antimalarial Bioavailabilities in Acute Falciparum Malaria
Authors: Newton Paul N. , van Vugt Michele , Teja-Isavadharm Paktiya , Siriyanonda Duangsuda , Rasameesoroj Maneerat , Teerapong Pramote , Ruangveerayuth Ronatrai , Slight Thra , Nosten Francois , Suputtamongkol Yupin , Looareesuwan Sornchai , White Nicholas J.
Published: July 2002

Plasma antimalarial activity following oral artesunate or dihydroartemisinin (DHA) treatment was measured by a bioassay in 18 patients with uncomplicated falciparum malaria. The mean antimalarial activity in terms of the bioavailability of DHA relative to that of artesunate did not differ significantly from 1, suggesting that DHA can be formulated to be an acceptable oral alternative to artesunate.
Different Aminoglycoside-Resistant Phenotypes in a Rabbit
Staphylococcus aureus
Endocarditis Infection Model
Authors: Asseray N. , Caillon J. , Roux N. , Jacqueline C. , Bismuth R. , Kergueris M. F. , Potel G. , Bugnon D.
Published: July 2002

The impact of different types of enzymatic resistance on the in vivo antibacterial activity of aminoglycosides (amikacin, gentamicin, and netilmicin) was studied in the rabbit endocarditis model with four strains of
Staphylococcus aureus
. Animals were treated in a manner simulating the administration of a single daily human dose. Amikacin had no effect on the three kanamycin-resistant strains despite apparent susceptibility in the disk diffusion test. Gentamicin appears to be the preferable aminoglycoside for treatment of staphylococcal infections.
Environmental Investigations of
Vibrio parahaemolyticus
in Oysters after Outbreaks in Washington, Texas, and New York (1997 and 1998)
Authors: DePaola Angelo , Kaysner Charles A. , Bowers John , Cook David W.
Published: July 2002

Total
Vibrio parahaemolyticus
densities and the occurrence of pathogenic strains in shellfish were determined following outbreaks in Washington, Texas, and New York. Recently developed nonradioactive DNA probes were utilized for the first time for direct enumeration of
V. parahaemolyticus
in environmental shellfish samples.
V. parahaemolyticus
was prevalent in oysters from Puget Sound, Wash.; Galveston Bay, Tex.; and Long Island Sound, N.Y., in the weeks following shellfish-associated outbreaks linked to these areas. However, only two samples (one each from Washington and Texas) were found to harbor total
V. parahaemolyticus
densities exceeding the level of concern of 10,000 g
−1
. Pathogenic strains, defined as those hybridizing with
tdh
and/or
trh
probes, were detected in a few samples, mostly Puget Sound oysters, and at low densities (usually <10 g
−1
). Intensive sampling in Galveston Bay demonstrated relatively constant water temperature (27.8 to 31.7°C) and
V. parahaemolyticus
levels (100 to 1,000 g
−1
) during the summer. Salinity varied from 14.9 to 29.3 ppt. A slight but significant (
P
< 0.05) negative correlation (−0.25) was observed between
V. parahaemolyticus
density and salinity. Based on our data, findings of more than 10,000 g
−1
total
V. parahaemolyticus
or >10 g
−1
tdh
- and/or
trh
-positive
V. parahaemolyticus
in environmental oysters should be considered extraordinary.
Molecular Epidemiological Survey of
Listeria monocytogenes
in Seafoods and Seafood-Processing Plants
Authors: Rørvik Liv Marit , Aase Brit , Alvestad Torill , Caugant Dominique A.
Published: July 2002

To evaluate the role of seafoods in the epidemiology of human listeriosis and the role of the processing environment as a source of
Listeria monocytogenes
in seafood products, 305
L. monocytogenes
isolates were characterized by multilocus enzyme electrophoresis using 21 genetic loci and restriction enzyme analysis of total DNA. Forty-four isolates were recovered from patients in Norway; 93 were isolated from seafoods, seafood-processing environments, and seawater from 55 different producers; and the remaining 168 isolates originated from six seafood-processing plants and one transport terminal examined in detail for
L. monocytogenes
. The patient isolates fell into 11 electrophoretic types, with four of them being responsible for 77% of the listeriosis cases in 1992 to 1996. Isolates from Norwegian seafoods and processing environments showed great genetic diversity, indicating that seafoods and seafood-processing environments do not offer a niche for specific
L. monocytogenes
strains. On the other hand, isolates from individual processing plants were genetically more homogenous, showing that plants are likely to be colonized with specific subclones of
L. monocytogenes
. The isolation of identical subclones of
L. monocytogenes
from both human patients and seafoods, including ready-to-eat products, suggests that such products may have been possible sources for listeriosis cases in Norway.
Effect of Temperature on Carbon and Electron Flow and on the Archaeal Community in Methanogenic Rice Field Soil
Authors: Fey Axel , Conrad Ralf
Published: July 2002

Temperature is an important factor controlling CH
4
production in anoxic rice soils. Soil slurries, prepared from Italian rice field soil, were incubated anaerobically in the dark at six temperatures of between 10 to 37°C or in a temperature gradient block covering the same temperature range at intervals of 1°C. Methane production reached quasi-steady state after 60 to 90 days. Steady-state CH
4
production rates increased with temperature, with an apparent activation energy of 61 kJ mol
−1
. Steady-state partial pressures of the methanogenic precursor H
2
also increased with increasing temperature from <0.5 to 3.5 Pa, so that the Gibbs free energy change of H
2
plus CO
2
-dependent methanogenesis was kept at −20 to −25 kJ mol of CH
4
−1
over the whole temperature range. Steady-state concentrations of the methanogenic precursor acetate, on the other hand, increased with decreasing temperature from <5 to 50 μM. Simultaneously, the relative contribution of H
2
as methanogenic precursor decreased, as determined by the conversion of radioactive bicarbonate to
14
CH
4
, so that the carbon and electron flow to CH
4
was increasingly dominated by acetate, indicating that psychrotolerant homoacetogenesis was important. The relative composition of the archaeal community was determined by terminal restriction fragment length polymorphism (T-RFLP) analysis of the 16S rRNA genes (16S rDNA). T-RFLP analysis differentiated the archaeal
Methanobacteriaceae
,
Methanomicrobiaceae
,
Methanosaetaceae
,
Methanosarcinaceae
, and Rice clusters I, III, IV, V, and VI, which were all present in the rice field soil incubated at different temperatures. The 16S rRNA genes of Rice cluster I and
Methanosaetaceae
were the most frequent methanogenic groups. The relative abundance of Rice cluster I decreased with temperature. The substrates used by this microbial cluster, and thus its function in the microbial community, are unknown. The relative abundance of acetoclastic methanogens, on the other hand, was consistent with their physiology and the acetate concentrations observed at the different temperatures, i.e., the high-acetate-requiring
Methanosarcinaceae
decreased and the more modest
Methanosaetaceae
increased with increasing temperature. Our results demonstrate that temperature not only affected the activity but also changed the structure and the function (carbon and electron flow) of a complex methanogenic system.
Effects of Glucosinolates and Flavonoids on Colonization of the Roots of
Brassica napus
by
Azorhizobium caulinodans
ORS571
Authors: O'Callaghan Kenneth J. , Stone Philip J. , Hu Xiaojia , Griffiths D. Wynne , Davey Michael R. , Cocking Edward C.
Published: July 2002

Plants of
Brassica napus
were assessed quantitatively for their susceptibility to lateral root crack colonization by
Azorhizobium caulinodans
ORS571(pXLGD4) (a rhizobial strain carrying the
lacZ
reporter gene) and for the concentration of glucosinolates in their roots by high-pressure liquid chromatography (HPLC). High- and low-glucosinolate-seed (HGS and LGS) varieties exhibited a relatively low and high percentage of colonized lateral roots, respectively. HPLC showed that roots of HGS plants contained a higher concentration of glucosinolates than roots of LGS plants. One LGS variety showing fewer colonized lateral roots than other LGS varieties contained a higher concentration of glucosinolates than other LGS plants. Inoculated HGS plants treated with the flavonoid naringenin showed significantly more colonization than untreated HGS plants. This increase was not mediated by a naringenin-induced lowering of the glucosinolate content of HGS plant roots, nor did naringenin induce bacterial resistance to glucosinolates or increase the growth of bacteria. The erucic acid content of seed did not appear to influence colonization by azorhizobia. Frequently, leaf assays are used to study glucosinolates and plant defense; this study provides data on glucosinolates and bacterial colonization in roots and describes a bacterial reporter gene assay tailored easily to the study of ecologically important phytochemicals that influence bacterial colonization. These data also form a basis for future assessments of the benefits to oilseed rape plants of interaction with plant growth-promoting bacteria, especially diazotrophic bacteria potentially able to extend the benefits of nitrogen fixation to nonlegumes.
Identification of thepgmGGene, Encoding a Bifunctional Protein with Phosphoglucomutase and Phosphomannomutase Activities, in the Gellan Gum-Producing StrainSphingomonas paucimobilisATCC 31461
Authors: Videira Paula A. , Cortes Luísa L. , Fialho Arsénio M. , Sá-Correia Isabel
Published: July 2002

ThepgmGgene ofSphingomonas paucimobilisATCC 31461, the industrial gellan gum-producing strain, was cloned and sequenced. It encodes a 50,059-Da polypeptide that has phosphoglucomutase (PGM) and phosphomannomutase (PMM) activities and is 37 to 59% identical to other bifunctional proteins with PGM and PMM activities from gram-negative species, includingPseudomonas aeruginosaAlgC. Purified PgmG protein showed a marked preference for glucose-1-phosphate (G1P); the catalytic efficiency was about 50-fold higher for G1P than it was for mannose-1-phosphate (M1P). The estimated apparentKmvalues for G1P and M1P were high, 0.33 and 1.27 mM, respectively. ThepgmGgene allowed the recovery of alginate biosynthetic ability in aP. aeruginosamutant with a defectivealgCgene. This result indicates that PgmG protein can convert mannose-6-phosphate into M1P in the initial steps of alginate biosynthesis and, together with other results, suggests that PgmG may convert glucose-6-phosphate into G1P in the gellan pathway.
Isolation and Characterization of
Desulfovibrio dechloracetivorans
sp. nov., a Marine Dechlorinating Bacterium Growing by Coupling the Oxidation of Acetate to the Reductive Dechlorination of 2-Chlorophenol
Authors: Sun Baolin , Cole James R. , Sanford Robert A. , Tiedje James M.
Published: July 2002

Strain SF3, a gram-negative, anaerobic, motile, short curved rod that grows by coupling the reductive dechlorination of 2-chlorophenol (2-CP) to the oxidation of acetate, was isolated from San Francisco Bay sediment. Strain SF3 grew at concentrations of NaCl ranging from 0.16 to 2.5%, but concentrations of KCl above 0.32% inhibited growth. The isolate used acetate, fumarate, lactate, propionate, pyruvate, alanine, and ethanol as electron donors for growth coupled to reductive dechlorination. Among the halogenated aromatic compounds tested, only the
ortho
position of chlorophenols was reductively dechlorinated, and additional chlorines at other positions blocked
ortho
dechlorination. Sulfate, sulfite, thiosulfate, and nitrate were also used as electron acceptors for growth. The optimal temperature for growth was 30°C, and no growth or dechlorination activity was observed at 37°C. Growth by reductive dechlorination was revealed by a growth yield of about 1 g of protein per mol of 2-CP dechlorinated, and about 2.7 g of protein per mole of 2,6-dichlorophenol dechlorinated. The physiological features and 16S ribosomal DNA sequence suggest that the organism is a novel species of the genus
Desulfovibrio
and which we have designated
Desulfovibrio dechloracetivorans
. The unusual physiological feature of this strain is that it uses acetate as an electron donor and carbon source for growth with 2-CP but not with sulfate.