bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of Multiplex PCRs for Detection of Common Viral Pathogens and Agents of Congenital Infections
Authors: McIver C. J. , Jacques C. F. H. , Chow S. S. W. , Munro S. C. , Scott G. M. , Roberts J. A. , Craig M. E. , Rawlinson W. D.
Published: October 2005

Potential
causes of congenital infection include
Toxoplasma gondii
and
viruses such as cytomegalovirus (CMV), enterovirus, hepatitis C virus,
herpes simplex virus types 1 and 2 (HSV-1 and -2), human herpesvirus
types 6, 7, and 8, lymphocytic choriomeningitis virus, parvovirus,
rubella virus, and varicella-zoster virus. Testing for each of these
agents using nucleic acid tests is time consuming and the availability
of clinical samples such as amniotic fluid or neonatal blood is often
limited. The aim of this study was to develop multiplex PCRs (mPCRs)
for detection of DNA and RNA agents in the investigation of congenital
infection and an mPCR for the viruses most commonly requested in a
diagnostic virology laboratory (CMV, Epstein-Barr virus, enterovirus,
HSV-1, HSV-2, and varicella-zoster virus). The assays were assessed
using known pathogen-positive tissues (cultures, placentae, plasma, and
amniotic fluid) and limits of detection were determined for all the
agents studied using serial dilutions of plasmid targets. Nested PCR
was performed as the most sensitive assay currently available, and
detection of the amplicons using hybridization to labeled probes and
enzyme-linked immunosorbent assay detection was incorporated into three
of the four assays. This allowed detection of 10 to 10
2
copies of each agent in the samples processed. In several patients, an
unexpected infection was diagnosed, including a case of encephalitis
where HSV was the initial clinical suspicion but CMV was detected. In
the majority of these cases the alternative agent could be confirmed
using reference culture, serology, or fluorescence methods and was of
relevance to clinical care of the patient. The methods described here
provide useful techniques for diagnosing congenital infections and a
paradigm for assessment of new multiplex PCRs for use in the diagnostic
laboratory.
Individual Donor Nucleic Acid Amplification Testing for Detection of West Nile Virus
Authors: Lee Dong-Hun , Mathew John , Pfahler Wolfram , Ma Dongling , Valinsky Jay , Prince Alfred M. , Andrus Linda
Published: October 2005

We have developed an economical, high-throughput nucleic acid amplification test (NAT) for blood-borne viruses, suitable for use in the screening of plasma samples from individual blood donors. This assay system includes a semiautomated procedure, using 96-well glass fiber plates for the extraction of viral nucleic acids from plasma and “universal beacon” technology which permits the detection of all genotypes of highly variable viruses (e.g., human immunodeficiency virus and hepatitis C virus). In this detection system, two fluorescent- detection technologies were employed successfully in a single tube: molecular beacon for West Nile virus (WNV) detection using a 6-carboxyfluorescein fluorophore and TaqMan for internal control detection using a VIC fluorophore. To establish proof of concept, we focused on the development of a robust individual donor NAT for WNV. The assay showed no reactivity to 15 other viruses tested or to 420 blood donor samples from the WNV pre-epidemic season. No cross-contamination was observed on an alternating positive-/negative-well test. The sensitivity (limit of detection, 95%) of the assay for WNV is between 3.79 and 16.3 RNA copies/ml, depending on which material was used as a standard. The assay detected all positive blood donation samples identified by the Roche WNV NAT. The assay can be performed qualitatively for screening and quantitatively for confirmation.
Comparison of Six DNA Extraction Methods for Recovery of Fungal DNA as Assessed by Quantitative PCR
Authors: Fredricks David N. , Smith Caitlin , Meier Amalia
Published: October 2005

The detection of fungal pathogens in clinical samples by PCR requires the use of extraction methods that efficiently lyse fungal cells and recover DNA suitable for amplification. We used quantitative PCR assays to measure the recovery of DNA from two important fungal pathogens subjected to six DNA extraction methods.
Aspergillus fumigatus
conidia or
Candida albicans
yeast cells were added to bronchoalveolar lavage fluid and subjected to DNA extraction in order to assess the recovery of DNA from a defined number of fungal propagules. In order to simulate hyphal growth in tissue,
Aspergillus fumigatus
conidia were allowed to form mycelia in tissue culture media and then harvested for DNA extraction. Differences among the DNA yields from the six extraction methods were highly significant (
P
< 0.0001) in each of the three experimental systems. An extraction method based on enzymatic lysis of fungal cell walls (yeast cell lysis plus the use of GNOME kits) produced high levels of fungal DNA with
Candida albicans
but low levels of fungal DNA with
Aspergillus fumigatus
conidia or hyphae. Extraction methods employing mechanical agitation with beads produced the highest yields with
Aspergillus
hyphae. The MasterPure yeast method produced high levels of DNA from
C. albicans
but only moderate yields from
A. fumigatus
. A reagent from one extraction method was contaminated with fungal DNA, including DNA from
Aspergillus
and
Candida
species. In conclusion, the six extraction methods produce markedly differing yields of fungal DNA and thus can significantly affect the results of fungal PCR assays. No single extraction method was optimal for all organisms.
Molecular Epidemiology of Methicillin-Resistant
Staphylococcus aureus
in Zürich, Switzerland (2003): Prevalence of Type IV SCC
mec
and a New SCC
mec
Element Associated with Isolates from Intravenous Drug Users
Authors: Qi Wei , Ender Miriam , O'Brien Frances , Imhof Alexander , Ruef Christian , McCallum Nadine , Berger-Bächi Brigitte
Published: October 2005

The majority of methicillin-resistant
Staphylococcus aureus
(MRSA) isolates, recovered in 2003 at the Department of Medical Microbiology in Zürich, Switzerland, belonged to major clones that are circulating worldwide. Staphylococcal cassette chromosome
mec
type IV (SCC
mec
-IV), harbored by half of the isolates, was found in sequence type 217 (ST217), which is an allelic variant of epidemic MRSA-15 (designated EMRSA-15), in a new local ST617 descending from clonal complex CC8 and in low-level oxacillin-resistant strains of multiple genetic lineages characteristic of community-onset MRSA. SCC
mec
-I, SCC
mec-
II, and SCC
mec
-III were in the minority, and four MRSA isolates had complex, rearranged SCC
mec
elements. A novel SCC
mec
-N1 of approximately 30 kb, associated with a
dfrA
gene and a
ccr4
-related recombinase complex, was identified in a large number of low-level oxacillin-resistant isolates, which descended from the successful clonal complex CC45 and are spreading among intraveneous drug users. In contrast, the SCC
mec
types of oxacillin-resistant coagulase-negative staphylococci (MRCNS) were of completely different composition. SCC
mec
type I (SCC
mec
-I) and SCC
mec
-II were more frequent than in the MRSA, while fewer contained SCC
mec
-IV. The other MRCNS displayed 11 different, complex patterns, suggesting frequent recombination between different SCC
mec
elements. With one
ccr
-negative exception, these strains amplified between one and three different
ccr
products, indicating either new varied complexes or multiple
ccr
loci. This suggests the presence of novel SCC
mec
types in MRCNS and no extensive interspecies SCC
mec
transfer between MRSA and MRCNS.
Molecular Phylogenetics of the Genus
Trichosporon
Inferred from Mitochondrial Cytochrome
b
Gene Sequences
Authors: Biswas Swarajit Kumar , Wang Li , Yokoyama Koji , Nishimura Kazuko
Published: October 2005

Mitochondrial cytochrome
b
(cyt
b
) genes of 42 strains representing 23 species of the genus
Trichosporon
were partially sequenced to determine their molecular phylogenetic relationships. Almost half of the 22 strains investigated (from 11 different species) contained introns in their sequences. Analysis of a 396-bp coding sequence from each strain of
Trichosporon
under investigation showed a total of 141 (35.6%) variable nucleotide sites. A phylogenetic tree based on the cyt
b
gene sequences revealed that all species of
Trichosporon
except
Trichosporon domesticum
and
Trichosporon montevideense
had species-specific cyt
b
genes.
Trichosporon
sp. strain CBS 5581 was identified as
Trichosporon pullulans
, and one clinical isolate, IFM 48794, was identified as
Trichosporon faecale
. Analysis of 132-bp deduced amino acid sequences showed a total of 34 (25.75%) variable amino acid sites.
T. domesticum
and
T. montevideense
,
Trichosporon asahii
and
Trichosporon asteroides
, and
Trichosporon gracile
and
Trichosporon guehoae
had identical amino acid sequences. A phylogenetic tree constructed with the ascomycetes
Saccharomyces douglasii
and
Candida glabrata
taken as outgroup species and including representative species from closely related genera species of
Trichosporon
clustered with other basidiomycetous yeasts that contain xylose in their cell wall compositions. These results indicate the effectiveness of mitochondrial cyt
b
gene sequences for both species identification and the phylogenetic analysis of
Trichosporon
species.
First Case of Septicemia Due to a Strain Belonging to Enteric Group 58 (
Enterobacteriaceae
) and Its Designation as
Averyella dalhousiensis
gen. nov., sp. nov., Based on Analysis of Strains from 20 Additional Cases
Authors: Johnson Andrew S. , Tarr Cheryl L. , Brown B. H. , Birkhead Karen M. , Farmer J. J.
Published: October 2005

When enteric group 58 was first described as a distinct new group of
Enterobacteriaceae
in 1985, there were only five known human isolates: four from wounds and one from feces. In 1996, we investigated the first blood isolate of enteric group 58, a case of sepsis in a 33-year-old woman receiving total parenteral nutrition. Fifteen additional clinical isolates have since been identified at CDC, including several recognized from a collection of “unidentified” strains dating back to 1973. All strains were characterized with a standard set of 49 biochemical tests used for
Enterobacteriaceae
, and the results were analyzed to determine phenotypic relatedness and best taxonomic fit. Antibiograms were determined as a taxonomic tool. Original identifications provided by submitting laboratories encompassed a wide variety of
Enterobacteriaceae
, including 14 species in eight genera, the most common being
Enterobacter
spp.,
Salmonella
spp.,
Serratia
spp.,
Kluyvera
spp., or
Escherichia
spp. Enteric group 58 strains have been most frequently isolated from traumatic injuries, fractures, and wounds and rarely from feces. Defining its clinical significance and distinguishing infection from colonization requires further study, but our case report indicates that serious systemic infection can occur. The vernacular name enteric group 58 was used from 1985 to 2004. In this paper, we formally name it
Averyella dalhousiensis
gen. nov., sp. nov., on the basis of its unique phenotype and its unique 16S rRNA gene sequence. These data indicate that enteric group 58 is not closely related to any of the existing genera or species of
Enterobacteriaceae
. The type strain is designated CDC9501-97, and a phenotypic definition is given based on all 21 strains.
Trichophyton eboreumsp. nov. Isolated from Human Skin
Authors: Brasch Jochen , Gräser Yvonne
Published: October 2005

An unusual dermatophyte was isolated from the plantar scales of a human immunodeficiency virus-positive man with tinea pedis. Morphology, physiology, and molecular data provided evidence to support the new speciesTrichophyton eboreum.This dermatophyte is characterized by rapid growth on common mycological media, a flat powdery off-white colony, formation of clavate microconidia, smooth- and thin-walled cylindrical or club-shaped macroconidia with two to nine cells, the presence of hook-shaped hyphae, the production of cleistothecium-like structures and spiral hyphae in older cultures, positive hair perforation, the absence of pigmentation on potato glucose agar, the absence of a requirement for vitamins, a weak positive urease reaction, no growth at 37°C, resistance to 5% NaCl, resistance to fluconazole, good growth on human epidermal keratin, and the production of various enzymes on different media by the API-ZYM test. More than 5% divergence from any known species of dermatophyte was revealed by sequence analysis of the internal transcribed spacer of the rRNA gene.
Contribution of Systematic Serological Testing in Diagnosis of Infective Endocarditis
Authors: Raoult D. , Casalta J. P. , Richet H. , Khan M. , Bernit E. , Rovery C. , Branger S. , Gouriet F. , Imbert G. , Bothello E. , Collart F. , Habib G.
Published: October 2005

Despite progress with diagnostic criteria, the type and timing of laboratory tests used to diagnose infective endocarditis (IE) have not been standardized. This is especially true with serological testing. Patients with suspected IE were evaluated by a standard diagnostic protocol. This protocol mandated an evaluation of the patients according to the modified Duke criteria and used a battery of laboratory investigations, including three sets of blood cultures and systematic serological testing for
Coxiella burnetii
,
Bartonella
spp.,
Aspergillus
spp.,
Legionella pneumophila
, and rheumatoid factor. In addition, cardiac valvular materials obtained at surgery were subjected to a comprehensive diagnostic evaluation, including PCR aimed at documenting the presence of fastidious organisms. The study included 1,998 suspected cases of IE seen over a 9-year period from April 1994 to December 2004 in Marseilles, France. They were evaluated prospectively. A total of 427 (21.4%) patients were diagnosed as having definite endocarditis. Possible endocarditis was diagnosed in 261 (13%) cases. The etiologic diagnosis was established in 397 (93%) cases by blood cultures, serological tests, and examination of the materials obtained from cardiac valves, respectively, in 348 (81.5%), 34 (8%), and 15 (3.5%) definite cases of IE. Concomitant infection with streptococci and
C. burnetii
was seen in two cases. The results of serological and rheumatoid factor evaluation reclassified 38 (8.9%) possible cases of IE as definite cases. Systematic serological testing improved the performance of the modified Duke criteria and was instrumental in establishing the etiologic diagnosis in 8% (34/427) cases of IE.
Mycobacterium avium
subsp.
paratuberculosis
, Genetic Susceptibility to Crohn's Disease, and Sardinians: the Way Ahead
Authors: Sechi Leonardo A. , Gazouli Maria , Ikonomopoulos John , Lukas John C. , Scanu Antonio M. , Ahmed Niyaz , Fadda Giovanni , Zanetti Stefania
Published: October 2005

The
present study was performed to determine what proportion of people in
Sardinia with or without Crohn's disease were infected with
Mycobacterium avium
subspecies
paratuberculosis
and
had a preponderance of allelic variants of Nod2, an intracellular
protein involved in Crohn's disease susceptibility. Genetic analysis of
the alleles of the NOD2/CARD15 gene (
insC3020
,
G908R, and R702W alleles), linked to susceptibility or
genetic predisposition to Crohn's disease in humans, was
carried out on specimens from 37 Crohn's disease patients and 34
patients without Crohn's disease. Our results show that more than 70
percent of people in Sardinia with Crohn's disease carry at least one
of the susceptibility-associated NOD2/CARD15 alleles and
were infected with
Mycobacterium avium
subspecies
paratuberculosis
.
Development of Daptomycin Resistance In Vivo in Methicillin-Resistant
Staphylococcus aureus
Authors: Hayden M. K. , Rezai K. , Hayes R. A. , Lolans K. , Quinn J. P. , Weinstein R. A.
Published: October 2005

Daptomycin is a new lipopeptide antibiotic that is rapidly bactericidal against
Staphylococcus aureus
. We report daptomycin resistance and treatment failure in 2 patients with osteomyelitis due to methicillin-resistant
S. aureus
. Disk diffusion susceptibility testing failed to detect resistance. Daptomycin at high concentration retained bactericidal activity against resistant isolates.
Rapid Screening of Urine Specimens for Bacteriuria by the Cellenium System
Authors: Pancholi Preeti , Pavletich Kathleen , Della-Latta Phyllis
Published: October 2005

This study evaluated the performance of the Cellenium 160US urine screening system in comparison to that of the semiquantitative culture method. The performance characteristics of the Cellenium system for all clinically significant uropathogens were 89.5% sensitivity, 94.4% specificity, 97.1% negative predictive value, and 81% positive predictive value.
Multi-Virulence-Locus Sequence Typing Clarifies Epidemiology of Recent Listeriosis Outbreaks in the United States
Authors: Chen Yi , Zhang Wei , Knabel Stephen J.
Published: October 2005

Multi-virulence-locus sequence typing (MVLST) was used to analyze isolates from two major listeriosis outbreaks in the United States in 1998 and 2002 that were due to consumption of contaminated hot dogs and turkey deli meat, respectively. MVLST demonstrated high epidemiological relevance and indicated that the two outbreaks were the result of one epidemic.
Changes in Serum Immunoglobulin G Levels as a Marker for
Cryptosporidium
sp. Infection in Peruvian Children
Authors: Priest Jeffrey W. , Bern Caryn , Roberts Jacquelin M. , Kwon James P. , Lescano Andres G. , Checkley William , Cabrera Lilia , Moss Delynn M. , Arrowood Michael J. , Sterling Charles R. , Gilman Robert H. , Lammie Patrick J.
Published: October 2005

In a retrospective analysis, we assessed the usefulness of two serologic enzyme-linked immunosorbent assays as epidemiologic tools for the detection of cryptosporidiosis episodes in children from a Peruvian community. The incidence rate determined by the serologic assay was higher than the rate determined by stool microscopy (0.77 versus 0.41 infection/child-year of surveillance).
Oligonucleotide Ligation Assay for Detection of Mutations Associated with Reverse Transcriptase and Protease Inhibitor Resistance in Non-B Subtypes and Recombinant Forms of Human Immunodeficiency Virus Type 1
Authors: Vega Yolanda , Pérez-Alvárez Lucía , Delgado Elena , Muñoz Mercedes , Casado Gema , Carmona Rocío , Sierra María , Vázquez de Parga Elena , Pinilla Milagros , García Valentina , Medrano Leandro , Contreras Gerardo , Thomson Miguel , Nájera Rafael
Published: October 2005

The oligonucleotide ligation assay is a genotypic assay for the detection of resistance-associated mutations to reverse transcriptase and protease inhibitors in human immunodeficiency virus type 1 subtype B. This assay has been modified and developed for non-B subtypes and recombinant strains and has been evaluated with sequencing, resulting in a more sensitive assay than sequencing for non-B subtypes.
Use of a Selective Enrichment Broth To Recover
Clostridium difficile
from Stool Swabs Stored under Different Conditions
Authors: Arroyo Luis G. , Rousseau Joyce , Willey Barbara M. , Low Don E. , Staempfli Henry , McGeer Allison , Weese J. Scott
Published: October 2005

The recovery of
Clostridium difficile
from the stools of patients with
C. difficile-
associated diarrhea was evaluated by use of an enrichment broth (cycloserine-cefoxitin fructose broth supplemented with 0.1% sodium taurocholate [TCCFB]) and was compared to that from selective agar (cycloserine-cefoxitin fructose agar [CCFA]) and alcohol shock followed by inoculation onto blood agar (AS-BA). TCCFB was superior to CCFA and AS-BA, and neither the storage time nor the storage temperature affected the recovery rate.
Comparison of Three Molecular Methods Used for Subtyping of
Legionella pneumophila
Strains Isolated during an Epidemic of Legionellosis in Rome
Authors: Scaturro M. , Losardo M. , De Ponte G. , Ricci M. L.
Published: October 2005

In the summer of 2003 a community-acquired outbreak of
Legionella pneumophila
occurred in Rome, Italy. Three molecular typing methods, pulse-field gel electrophoresis, amplified fragment length polymorphism analysis, and sequence-based typing (SBT), were used to establish the clonal correlation among the isolates of the epidemic cluster. By comparison of the methods, SBT was the most rapid and the easiest to perform and provided unambiguous results.
Urinary
d
-Arabinitol/
l
-Arabinitol Levels in Infants Undergoing Long-Term Antibiotic Therapy
Authors: Stradomska Teresa J. , Bobula-Milewska Bogumiła , Bauer Anna , Mielniczuk Zbigniew , Dąbkowska Maria , Syczewska Małgorzata , Dzierżanowska Danuta
Published: October 2005

Long-term antibiotic therapy is one of the main risk factors for mycosis. The urinary
d
-arabinitol/
l
-arabinitol (
d
-/
l
-ARA) ratio (a biomarker of several
Candida
species) was determined by gas chromatography with an electron capture detector in samples from 51 infants undergoing long-term antibiotic therapy. Although 47 of these children had higher
d
-/
l
-ARA ratios than healthy controls (
P
< 0.0003), their values nonetheless remained within upper-normal limits (
d
-/
l
-ARA ratio of <3.6). Four children with suspected invasive candidiasis had above-normal ratios that normalized with fluconazole treatment.
Tularemia in Denmark: Identification of a
Francisella tularensis
subsp.
holarctica
Strain by Real-Time PCR and High-Resolution Typing by Multiple-Locus Variable-Number Tandem Repeat Analysis
Authors: Byström Mona , Böcher Sidsel , Magnusson Anna , Prag Jørgen , Johansson Anders
Published: October 2005

We report ulceroglandular tularemia affecting an 8-year-old boy and the first recovery of
Francisella tularensis
in Denmark. A novel real-time PCR assay was used to identify the strain as
F. tularensis
subsp.
holarctica
(type B). Multiple-locus variable-number tandem repeat analysis demonstrated a close genetic relationship to strains from Norway.
Fatal Pulmonary Infection Associated with a Novel Organism, “
Parastreptomyces abscessus
”
Authors: Nichols W. Garrett , Prentice Jennifer , Houze Yolanda , Carlson LaDonna , Cookson Brad T.
Published: October 2005

Actinomycetes are increasingly recognized as pathogenic in the immunocompromised host. We isolated an asporogenous, nonmotile, aerobic gram-positive rod from a transplant recipient with a fatal pulmonary infection. The pathology was similar to that associated with
Rhodococcus equi
, including intrahistiocytic localization. The organism was relatively inert in standard biochemical tests. 16S rRNA gene sequencing indicated a potentially unique organism most closely related to the genus
Streptomyces
, for which we propose the name “
Parastreptomyces abscessus
.”
Clinical Progression of Methicillin-Resistant
Staphylococcus aureus
Vertebral Osteomyelitis Associated with Reduced Susceptibility to Daptomycin
Authors: Vikram Holenarasipur R. , Havill Nancy L. , Koeth Laura M. , Boyce John M.
Published: October 2005

Daptomycin, a novel cyclic lipopeptide antibiotic, exhibits rapid bactericidal activity in vitro against most clinically relevant gram-positive organisms, including drug-resistant pathogens. Herein we describe a patient in whom methicillin-resistant
Staphylococcus aureus
with reduced susceptibility to daptomycin was responsible for bacteremia and progressive vertebral osteomyelitis during daptomycin therapy.
Reduced Levofloxacin Susceptibility and Tetracycline Resistance in a Clinical Isolate of
Haemophilus quentini
Identified by 16S rRNA Sequencing
Authors: Mak Gannon C. , Ho P. L. , Tse Cindy W. S. , Lau Susanna K. P. , Wong Samson S. Y.
Published: October 2005

This paper reports the first case of
Haemophilus quentini
bacteremia with reduced susceptibility to levofloxacin and resistance to nalidixic acid identified by 16S rRNA sequencing. There was an S84L substitution in
gyrA
and an S84I substitution in
parC
. The isolate had coresistance to ampicillin (β-lactamase positive) and tetracycline mediated by the
tet
(B) gene.
Breakthrough
Candida krusei
Fungemia during Fluconazole Prophylaxis followed by Breakthrough Zygomycosis during Caspofungin Therapy in a Patient with Severe Aplastic Anemia Who Underwent Stem Cell Transplantation
Authors: Girmenia Corrado , Moleti Maria Luisa , Micozzi Alessandra , Iori Anna Paola , Barberi Walter , Foà Robin , Martino Pietro
Published: October 2005

We report a case of breakthrough invasive zygomycosis in a stem cell transplant recipient who was receiving caspofungin for treatment of a breakthrough
Candida krusei
fungemia that occurred during fluconazole prophylaxis. Also, patients receiving the echinocandin caspofungin remain at risk for pathogens, such as zygomycetes, that are intrinsically resistant to this agent.
Combination Assay Detecting both Human Immunodeficiency Virus (HIV) p24 Antigen and Anti-HIV Antibodies Opens a Second Diagnostic Window
Authors: Speers David , Phillips Peter , Dyer John
Published: October 2005

Fourth-generation human immunodeficiency virus (HIV) screening immunoassays reduce the diagnostic window between infection and diagnosis by the inclusion of HIV p24 antigen detection together with HIV antibody detection in the same test. We compared third- and fourth-generation HIV immunoassays and a dedicated HIV p24 antigen test for detection of a case of HIV seroconversion. This demonstrated a second diagnostic window using the fourth-generation assay due to a decline of HIV p24 antigen prior to the detection of HIV antibody. However, HIV p24 antigen was detected in the same sample by the dedicated HIV p24 antigen test, as was HIV proviral DNA. Although it is likely to be rare, this phenomenon has also been reported for other fourth-generation HIV immunoassays and has implications for the reported diagnostic windows of these assays.
PIONIC ATOMS PROBING πNN RESONANCES
Authors: KRIVORUCHENKO M. I. , MARTEMYANOV B. V. , FAESSLER AMAND , FUCHS C.
Published: October 2005

The pion optical potential generated by the hypothetical πNN-coupled NN-decoupled dibaryon resonance d′(2065) is calculated to the lowest order in nuclear matter density. The contribution to the pion optical potential is found to be within the empirical errors, so the d′(2065) existence currently does not contradict to the observed properties of the π--nucleus bound states. Future progress in the pionic X-ray spectroscopy can reveal contributions of πNN resonances to energy levels and widths of the pionic atoms.
THE KINETIC DESCRIPTION OF VACUUM PARTICLE CREATION IN THE OSCILLATOR REPRESENTATION
Authors: PERVUSHIN V. N. , SKOKOV V. V. , REICHEL A. V. , SMOLYANSKY S. A. , PROZORKEVICH A. V.
Published: October 2005

The oscillator representation is used for the nonperturbative description of vacuum particle creation in a strong time-dependent electric field in the framework of scalar QED. It is shown that the method can be more effective for the derivation of the quantum kinetic equation (KE) in comparison with the Bogoliubov method of time-dependent canonical transformations. This KE is used for the investigation of vacuum creation in periodical linear and circular polarized electric fields and also in the case of the presence of a constant magnetic field, including the back reaction problem. In particular, these examples are applied for a model illustration of some features of vacuum creation of electron–positron plasma within the planned experiments on the X-ray free electron lasers.
MAKING AN ANALOGY BETWEEN A MULTI-CHAIN INTERACTION IN CHARGE DENSITY WAVE TRANSPORT AND THE USE OF WAVE FUNCTIONALS TO FORM S–S′ PAIRS
Authors: BECKWITH A. W.
Published: October 2005

First, we show through a numerical simulation that the massive Schwinger model used to formulate solutions to CDW transport in itself is insufficient for the transport of soliton–antisoliton (S–S′) pairs through a pinning gap model of CDW transport. We show that a model Hamiltonian with Peierls condensation energy used to couple adjacent chains (or transverse wave vectors) permits the formation of S–S′ pairs which could be used to transport CDW through a potential barrier. Previously, we have argued that there are analogies between this construction and the false vacuum hypothesis used for showing a necessary and sufficient condition for formation of CDW S–S′ pairs in wavefunctionals. Here we note that this can be established via either the use of the Bogomil'nyi inequality or an experimental artifact which is due to the use of the false vacuum hypothesis to obtain a proportional "distance" between the S–S′ charge centers.
INFINITE NETWORK OF IDENTICAL CAPACITORS BY GREEN'S FUNCTION
Authors: ASAD J. H. , HIJJAWI R. S. , SAKAJI A. J. , KHALIFEH J. M.
Published: October 2005

The capacitance between arbitrary nodes in perfect infinite networks of identical capacitors is studied. We calculate the capacitance between the origin and the lattice site (l, m) for an infinite linear chain, and for an infinite square network consisting of identical capacitors using the Lattice Green's Function. The asymptotic behavior of the capacitance for an infinite square lattice is investigated for infinite separation between the origin and the site (l, m). We point out the relation between the capacitance of the lattice and the van Hove singularity of the tight-binding Hamiltonian. This method can be applied directly to other lattice structures.
MAGNETORESISTIVITY AND MAGNETIC PROPERTIES IN MgB2 THIN FILMS
Authors: YANG T. R. , ILONCA G. , POP A. V. , TOMA V. , MATEI I. , BEIUŞAN F.
Published: October 2005

Magnetotransport data on MgB 2 thin films, fabricated on Al 2 O 3 substrates using electron–bean deposition and Mg diffusion method are reported for applied magnetic fields up to 9 T. The upper critical field anisotropy, lower critical field and irreversibility field versus temperature are determined. The Hall coefficient is slightly temperature-dependent and positive in the normal state. Using the extracted data, the electronic mean free path, coherence length ξ0, anisotropic coefficient γ and penetration depth λ are calculated.
SPIN FLUCTUATIONS AND ANHARMONICITY IN ITINERANT ELECTRON MAGNETISM
Authors: SOLONTSOV A.
Published: October 2005

The paper overviews recent investigations of thermodynamics and magnetic dynamics of itinerant electron magnets with strongly coupled (anharmonic) spin fluctuations (SF). A novel classification scheme for SF, dependent on their spatial dispersion and quantum effects is presented, including the generalized Fermi liquid (FL), soft-mode (SM), and localized moments (LM) regimes. It is shown that the conventional SCR theory of Moriya holds only in the weak coupling limit of the SM regime and cannot be applied to real magnets where spin anharmonicity induced by zero-point SF is expected to be strong. To account for the effects of strong spin anharmonicity, a variational SM theory of SF is presented. These effects essentially influence thermodynamics of itinerant magnets and affect the criterion for magnetic instabilities, equations of state, low temperature specific heat, non-FL and quantum critical behavior, etc. Nonlinear magnetic dynamics of itinerant magnets is analyzed based on the phenomenological spin-invariant dynamical equations both in the spin wave and relaxational regimes. Macroscopic magnetic dynamics and different mechanisms of magnon damping in the spin wave regime are shown to be essentially different from the results arising for the Heisenberg magnets. The relaxational regime may be strongly influenced by nonlinear effects of mode-mode couplings. The spectrum of overdamped longitudinal SF is shown to be radically changed due to their scattering by magnons, which may result in a quasielasic peak in the SF spectrum and inelastic SF near the magnon frequencies, depending on nonlinear coupling. The quasielastic SF are suppressed at low temperatures and develop at elevated temperatures, dominating near the Curie point. The results are applied to the magnetoresistive manganites.
A CONCEPTUAL APPROACH OF ENTREPRENEURIAL ORIENTATION WITHIN SMALL BUSINESS CONTEXT
Authors: ALOULOU WASSIM , FAYOLLE ALAIN
Published: October 2005

There is abundant literature about individual entrepreneurship (entrepreneurs) and about corporate entrepreneurship within organizations. But little is written about a related concept like Entrepreneurial Orientation (EO) in small businesses, and also, about how to describe its role in their strategic formulation.

The paper attempts to identify the main attributes of the EO concept and its determinants within small business context. EO consists of three components: Innovativeness, proactiveness, and risk-taking by strategic leaders in these firms. An innovative small business wilI not be an entrepreneurial if it does not take risks or is not sufficiently proactive towards competitors and environment.

After describing the emergence of this concept, the paper shows the importance of the EO as a valid strategic orientation for small businesses when they re-think their strategic analyses with Opportunity-based and Resource-based views. Adopting such orientation seems to reflect a needed conciliation between other strategic orientations (market-, technology- and stakeholder orientations) and altogether blending of them.

Finally, the paper concludes with proposing some implications for future research to deepen the study (conceptually and empirically) of the EO within small business context.
Multistability in tubuloglomerular feedback and spectral complexity in spontaneously hypertensive rats
Authors: Layton Anita T. , Moore Leon C. , Layton Harold E.
Published: October 2005

Single-nephron proximal tubule pressure in spontaneously hypertensive rats (SHR) can exhibit highly irregular oscillations similar to deterministic chaos. We used a mathematical model of tubuloglomerular feedback (TGF) to investigate potential sources of the irregular oscillations and the corresponding complex power spectra in SHR. A bifurcation analysis of the TGF model equations, for nonzero thick ascending limb (TAL) NaCl permeability, was performed by finding roots of the characteristic equation, and numerical simulations of model solutions were conducted to assist in the interpretation of the analysis. These techniques revealed four parameter regions, consistent with TGF gain and delays in SHR, where multiple stable model solutions are possible: 1) a region having one stable, time-independent steady-state solution; 2) a region having one stable oscillatory solution only, of frequency f1; 3) a region having one stable oscillatory solution only, of frequency f2, which is approximately equal to 2 f1; and 4) a region having two possible stable oscillatory solutions, of frequencies f1 and f2. In addition, we conducted simulations in which TAL volume was assumed to vary as a function of time and simulations in which two or three nephrons were assumed to have coupled TGF systems. Four potential sources of spectral complexity in SHR were identified: 1) bifurcations that permit switching between different stable oscillatory modes, leading to multiple spectral peaks and their respective harmonic peaks; 2) sustained lability in delay parameters, leading to broadening of peaks and of their harmonics; 3) episodic, but abrupt, lability in delay parameters, leading to multiple peaks and their harmonics; and 4) coupling of small numbers of nephrons, leading to multiple peaks and their harmonics. We conclude that the TGF system in SHR may exhibit multistability and that the complex power spectra of the irregular TGF fluctuations in this strain may be explained by switching between multiple dynamic modes, temporal variation in TGF parameters, and nephron coupling.
An IGF-I antagonist does not inhibit renal fibrosis in the rat following subtotal nephrectomy
Authors: Oldroyd Simon D. , Miyamoto Yohie , Moir Arthur , Johnson Timothy S. , El Nahas A. Meguid , Haylor John L.
Published: October 2005

Insulin-like growth factor I (IGF-I) has been proposed as a mediator of kidney scarring, although no interventional studies on the role of IGF-I in models of chronic kidney disease have been reported. The effect of a peptide IGF-I receptor antagonist (JB3) has been examined on kidney fibrosis and function in the rat following 5/6 subtotal nephrectomy (SNx). Male Wistar rats were anesthetized with halothane and subjected to SNx. JB3 was delivered by subcutaneous infusion using Alzet osmotic minipumps. In vitro studies showed JB3 to displace125I-IGF-I binding to isolated rat glomeruli and to inhibit IGF-I-induced receptor phosphorylation in renal tubular cells in culture. In the 7-day SNx rats, IGF-I immunostain was present in collecting tubules and JB3 inhibited compensatory renal growth, the maximum effect occuring at 10 μg·kg−1·day−1. After 90 days, the SNx rats developed proteinuria, hypertension, and a fall in glomerular filtration rate. IGF-I immunostain was present in the tubulointerstitial space of the remnant kidney together with marked tubulointerstitial fibrosis. Treatment with JB3 at a dose of 10 μg·kg−1·day−1had no effect on the renal fibrosis measured by Masson's trichrome staining or immunostain for collagen III and collagen IV. The proteinuria, hypertension, and lower creatinine clearance all remained unchanged. The remnant kidney was associated with a 50% decrease in renal IGF-I mRNA, which was partially restored by treatment with JB3. Thus an interventional study with an IGF-I receptor antagonist does not support a role for IGF-I in the development of renal fibrosis in the SNx rat, although IGF-I does make an important contribution to compensatory kidney growth.
Persistent NF-κB activation in renal epithelial cells in a mouse model of HIV-associated nephropathy
Authors: Martinka Scott , Bruggeman Leslie A.
Published: October 2005

Human immunodeficiency virus (HIV)-associated nephropathy (HIVAN) is caused, in part, by direct infection of kidney epithelial cells by HIV-1. In the spectrum of pathogenic host-virus interactions, abnormal activation or suppression of host transcription factors is common. NF-κB is a necessary host transcription factor for HIV-1 gene expression, and it has been shown that NF-κB activity is dysregulated in many naturally infected cell types. We show here that renal glomerular epithelial cells (podocytes) expressing the HIV-1 genome, similar to infected immune cells, also have a dysregulated and persistent activation of NF-κB. Although podocytes produce p50, p52, RelA, RelB, and c-Rel, electrophoretic mobility shift assays and immunocytochemistry showed a predominant nuclear accumulation of p50/RelA-containing NF-κB dimers in HIV-1-expressing podocytes compared with normal. In addition, the expression level of a transfected NF-κB reporter plasmid was significantly higher in HIVAN podocytes. The mechanism of NF-κB activation involved increased phosphorylation of IκBα, resulting in an enhanced turnover of the IκBα protein. There was no evidence for regulation by IκBβ or the alternate pathway of NF-κB activation. Altered activation of this key host transcription factor likely plays a role in the well-described cellular phenotypic changes observed in HIVAN, such as proliferation. Studies with inhibitors of proliferation and NF-κB suggest that NF-κB activation may contribute to the proliferative mechanism in HIVAN. In addition, because NF-κB regulates many aspects of inflammation, this dysregulation may also contribute to disease severity and progression through regulation of proinflammatory processes in the kidney microenvironment.
Short-term nitric oxide inhibition induces progressive nephropathy after regression of initial renal injury
Authors: Fujihara Clarice K. , Sena Claudia R. , Malheiros Denise M. A. C. , Mattar Ana L. , Zatz Roberto
Published: October 2005

Chronic nitric oxide (NO) inhibition and salt overload (HS) promote severe hypertension and renal injury, which regress quickly, although not completely, on treatment withdrawal. We investigated whether renal function and structure remain stable 6 mo after cessation of these treatments. Adult male Munich-Wistar rats were distributed among three groups: HS, receiving 3.1% Na diet; HS+N, receiving HS and the NO inhibitor Nω-nitro-l-arginine methyl ester (l-NAME; 30 mg·kg−1·day−1orally); and HS+N+L, receiving HS+N and the ANG II blocker losartan (L; 50 mg·kg−1·day−1orally). In studies performed after 20 days of treatment ( protocol 1), HS+N rats exhibited severe glomerular and systemic hypertension, massive albuminuria, glomerular and interstitial injury, and infiltration by macrophages and cells expressing ANG II. These abnormalities were largely prevented in the HS+N+L group. A second cohort ( protocol 2) received HS+N for 20 days, followed by a conventional (0.5% Na) diet and no l-NAME treatment during the subsequent 30 days. At this time, systemic and glomerular pressure, along with parameters of renal injury and inflammation, were still higher than in HS or HS+N+L rats, although differences were much smaller than in protocol 1. Six months after 20-day l-NAME/salt overload treatment was ceased ( protocol 3), severe albuminuria, hypertension, and renal injury developed in HS+N rats. Again, losartan prevented most of these changes. We conclude 1) short-term HS+N treatment triggers the autonomous development of progressive glomerulosclerosis; 2) this process may involve activation of the AT1receptor; and 3) temporary HS+N treatment may represent a new model of slowly progressive chronic nephropathy.
Dominant-negative regulation of WNK1 by its kidney-specific kinase-defective isoform
Authors: Subramanya Arohan R. , Yang Chao-Ling , Zhu Xiaoman , Ellison David H.
Published: October 2005

With-no-lysine kinase-1 (WNK1) gene mutations cause familial hyperkalemic hypertension (FHHt), a Mendelian disorder of excessive renal Na+ and K+ retention. Through its catalytic activity, full-length kinase-sufficient WNK1 (L-WNK1) suppresses its paralog, WNK4, thereby upregulating thiazide-sensitive Na-Cl cotransporter (NCC) activity. The predominant renal WNK1 isoform, KS-WNK1, expressed exclusively and at high levels in distal nephron, is a shorter kinase-defective product; the function of KS-WNK1 must therefore be kinase independent. Here, we report a novel role for KS-WNK1 as a dominant-negative regulator of L-WNK1. Na+ transport studies in Xenopus laevis oocytes demonstrate that KS-WNK1 downregulates NCC activity indirectly, by inhibiting L-WNK1. KS-WNK1 also associates with L-WNK1 in protein complexes in oocytes and attenuates L-WNK1 kinase activity in vitro. These observations suggest that KS-WNK1 plays an essential role in the renal molecular switch regulating Na+ and K+ balance; they provide insight into the kidney-specific phenotype of FHHt.
Supporting Family Caregivers in Stroke Care
Authors: Lui May H.L. , Ross Fiona M. , Thompson David R.
Published: October 2005

Background and Purpose—

Teaching effective problem-solving skills to family caregivers of patients with chronic disease has been shown to be useful for promoting physical and psychosocial well-being. However, the use and effectiveness of problem solving for supporting caregivers in stroke care has not been reviewed. This article aims to identify and review studies that have examined the effectiveness of teaching problem solving skills to caregivers in stroke care, highlight gaps in the evidence base, and recommend avenues for additional research.

Methods—

A structured review of literature identified from nursing, medicine, and psychology databases from 1970 to 2004 was conducted. Eleven articles reporting the development or evaluation of effective problem-solving interventions for caregivers of patients with stroke were critically appraised using recognized quality criteria.

Results—

The results of this review show that the strength of evidence for problem-solving interventions for caregivers of stroke patients is limited. Because some studies used small samples and varied methods and interventions, making a comparison was difficult. Caregivers’ problem-solving abilities were rarely measured, and the theoretical concepts and framework underpinning most studies were unclear.

Conclusions—

Evidence from the review suggests a need to additionally study the link between theoretical concepts of effective problem solving and outcomes using standardized measures and to examine also the processes involved in implementing the intervention using multimethod designs, including both quantitative and qualitative approaches.
Corm rot of giant swamp taro (Cyrtosperma merkusii) caused by the burrowing nematode Radopholus similis (Nematoda: Pratylenchidae) in the Pacific
Authors: Tiedt Laurens , De Waele Dirk , van den Berg Esther , Josekutty Puthiyaparambil , Murukesan Vazhaveli
Published: October 2005

The association between the burrowing nematode Radopholus similis and giant swamp taro is studied in detail for the first time in corms collected from swampy taro patches in Yap, one of the states of the Federated States of Micronesia. The R. similis population from Yap displays similar variation in morphometrics and morphology as reported in the literature. The rot caused by the nematodes is wet with a loose mass of brown dead tissues and a deep brown necrotic centre housing nematodes inside. Usually, the infected tissues spread a disgusting odour typical of this disease. The dead tissues progress into shallow to deep cavities that advance towards the edible, central portion of the corm giving a perforated appearance on the outside of the otherwise smooth corm. The disease becomes more severe as the age of the plant increases. Nematode-infected plants seldom show any above-ground symptoms. The market quality of the corm is greatly reduced by the nematode damage. The widespread occurrence of the disease and the type of damage R. similis causes to the corms pose a serious threat to giant swamp taro production, food security and the continuation of traditional customs on those islands where R. similis occurs.
A study on disease development and early diagnosis of pine wood nematode, Bursaphelenchus xylophilus, infection of Japanese black pine
Authors: Ye Jian-Ren , Li Yan , Tan Jia-Jin , Wu Xiao-Qin , Zhu Yun-Feng
Published: October 2005

The disease development and some physiobiochemical indices of 3-4-year-old Pinus thunbergii inoculated with Bursaphelenchus xylophilus were studied. The results showed that after nematode invasion, the disease expanded from the base to the upper part of the main stem, there was an interruption of resin exudation, drying and pith browning occurred sequentially in stem xylem, then the needles wilted and finally the plant died. The number of nematodes increased continuously and rapidly, and increased significantly just after symptoms appeared in pine seedlings. The stem water content decreased gradually, stem and leaf relative water content in a new season branch began to decrease not long before symptoms appeared, and the optical density of organic acid extract from the stem of pine seedlings increased. It is suggested that stem water content could be used as a disease indicator, and organic acid would be the most reliable physiobiochemical index for early diagnosis of the disease.