bluuebunny/crossref_metadata_2025_split huggingface dataset:
Clinically normal atopic skin vs. non‐atopic skin as seen through electrical impedance
Authors: Nicander Ingrid , Ollmar Stig 
Published: July 2004

Background/aims: In an earlier study, we have shown that the electrical impedance (IMP) is dependent on the lipid content of the stratum corneum as studied by lipid extraction. Therefore, we now employ the IMP technique to compare the properties of clinically normal atopic skin with that of non‐atopic skin. We looked at the same time at concomitant alterations in transepidermal water loss (TEWL) and skin moisture results.Methods: Twenty‐two healthy participants and 26 patients with atopic dermatitis were recruited. One test site on each volar forearm was used in the test procedure, of cyclohexane swabbing, skin stripping, and lipid extraction using a mixture of hexane:isopropanol. Responses were evaluated by measuring TEWL, skin moisture using electrical capacitance, and finally IMP spectroscopy in the frequency range 1 kHz to 1 MHz before the start of the study, after each step of the test procedure, and also during a 2 weeks recovery period.Results: Only the IMP results showed significant changes between baseline values of clinically normal atopic skin and healthy skin. Furthermore, IMP and TEWL showed significantly larger reactivity for the atopic group after the skin stripping procedure, and IMP after lipid extraction as well.Conclusion: Our results show that IMP is a useful method for detection of changes in the lipid content of the stratum corneum by discriminating healthy looking atopic skin from healthy control skin, and to detect changes in reactivity between the two groups.
In vivo morphological characterisation of skin by MRI micro‐imaging methods
Authors: Mirrashed Fakhereh , Sharp Jonathan C. 
Published: July 2004

Background/purpose: Quantitative assessments in skin layers using images obtained with standard magnetic resonance imaging (MRI) sequences are limited, since the stratum corneum and dermis, the layers of most clinical interest, have low signal due to their short spin–spin relaxation, T2.Methods: In the present work, different methods of MRI contrast, such as magnetisation transfer contrast (MTC), T1‐weighting (where T1 is spin–lattice relaxation time), T2*‐weighting (where T2* is the combination of T2 and magnetic field in‐homogeneity effect) and chemical shift, were used. These techniques were combined with high‐resolution MRI.Results: We found that skin is a very MT active tissue, and MTC provides data enabling the evaluation of how the tissue in skin layers interacts with the interstitial fluids. Details obtained from high‐resolution high‐quality in vivo skin images with different contrast allowed for differentiation of skin layers, sub‐layers and excellent correlation of MR data with known histological features and water constituent of skin layers.Conclusion: Combining MT and other MRI data employing other contrast mechanisms provides a superior non‐invasive in vivo technique for visualisation and also quantitative assessment of the constituents of the stratum corneum, epidermis, papillary dermis, reticular dermis and hypodermis as major structural layers of the skin. This type of study can be extended to cutaneous disease states or skin ageing, where defects in water mobility, concentration and/or macromolecular structural changes are expected.
Topical negative pressure therapy: mechanisms and indications
Authors: Banwell Paul E , Musgrave Melinda 
Published: July 2004

AbstractTopical negative pressure (TNP) therapy has emerged as a high‐technology, microprocessor‐controlled physical wound‐healing modality. Complex effects at the wound–dressing interface following application of a controlled vacuum force have been documented. These include changes on a microscopic, molecular level and on a macroscopic, tissue level: interstitial fluid flow and exudate management, oedema reduction, effects on wound perfusion, protease profiles, growth factor and cytokine expression and cellular activity, all leading to enhanced granulation tissue formation and improved wound‐healing parameters. Primary indications for clinical use have been documented and include traumatic wounds, open abdominal wounds, infected sternotomy wounds, wound bed preparation, complex diabetic wounds and skin‐graft fixation. Whilst this therapy now forms an essential part of the wound healing armamentarium, extensive clinical trials are recommended to confirm efficacy and delineate its optimum use.
An unusual lesion on the chest wall
Authors: Pandey Manoj , Chandramohan K Nair , Mathew Anitha 
Published: July 2004

AbstractOsteoradionecrosis is an exceptional complication after the treatment of breast carcinoma. We report here a 63‐year‐old woman who presented with osteoradionecrosis of the sternum 17 years after initial treatment for breast cancer. Difficulty in diagnosing the lesion and its management is discussed.
Putative Exopolysaccharide Synthesis Genes Influence
Pseudomonas aeruginosa
Biofilm Development
Authors: Matsukawa Masanori , Greenberg E. P. 
Published: July 2004

ABSTRACT

An analysis of the
Pseudomonas aeruginosa
genomic sequence revealed three gene clusters, PA1381-1393, PA2231-2240, and PA3552-3558, in addition to the alginate biosynthesis gene cluster, which appeared to encode functions for exopolysaccharide (EPS) biosynthesis. Recent evidence indicates that alginate is not a significant component of the extracellular matrix in biofilms of the sequenced
P. aeruginosa
strain PAO1. We hypothesized that at least one of the three potential EPS gene clusters revealed by genomic sequencing is an important component of
P. aeruginosa
PAO1 biofilms. Thus, we constructed mutants with chromosomal insertions in PA1383, PA2231, and PA3552. The mutant with a PA2231 defect formed thin unstructured abnormal biofilms. The PA3552 mutant formed structured biofilms that appeared different from those formed by the parent, and the PA1383 mutant formed structured biofilms that were indistinguishable from those formed by the parent. Consistent with a previous report, we found that polysaccharides were one component of the extracellular matrix, which also contained DNA. We suggest that the genes that were inactivated in our PA2231 mutant are required for the production of an EPS, which, although it may be a minor constituent of the matrix, is critical for the formation of
P. aeruginosa
PAO1 biofilms.
Detachment Characteristics and Oxacillin Resistance of
Staphyloccocus aureus
Biofilm Emboli in an In Vitro Catheter Infection Model
Authors: Fux C. A. , Wilson S. , Stoodley P. 
Published: July 2004

ABSTRACT

Catheter-related bloodstream infections due to
Staphylococcus aureus
are of increasing clinical importance. The pathophysiological steps leading to colonization and infection, however, are still incompletely defined. We observed growth and detachment of
S. aureus
biofilms in an in vitro catheter-infection model by using time-lapse microscopy. Biofilm emboli were characterized by their size and their susceptibility for oxacillin. Biofilm dispersal was found to be a dynamic process in which clumps of a wide range of diameters detach. Large detached clumps were highly tolerant to oxacillin compared with exponential-phase planktonic cultures. Interestingly, the degree of antibiotic tolerance in stationary-phase planktonic cultures was equal to that in the large clumps. The mechanical disruption of large clumps reduced the minimal bactericidal concentration (MBC) by more than 1,000 times. The MBC for whole biofilm effluent, consisting of particles with an average number of 20 bacteria was 3.5 times higher than the MBC for planktonic cultures. We conclude that the antibiotic resistance of detached biofilm particles depends on the embolus size and could be attributed to nutrient-limited stationary-phase physiology of cells within the clumps. We hypothesize that the detachment of multicellular clumps may explain the high rate of symptomatic metastatic infections seen with
S. aureus
.
Synthesis of the Heteropolysaccharide O Antigen ofEscherichia coliO52 Requires an ABC Transporter: Structural and Genetic Evidence
Authors: Feng Lu , Senchenkova Sof'ya N. , Yang Jinghua , Shashkov Alexander S. , Tao Jiang , Guo Hongjie , Cheng Jiansong , Ren Yi , Knirel Yuriy A. , Reeves Peter R. , Wang Lei 
Published: July 2004

ABSTRACTThe structural and genetic organization of theEscherichia coliO52 O antigen was studied. As identified by sugar and methylation analysis and nuclear magnetic resonance spectroscopy, the O antigen ofE. coliO52 has a partially O-acetylated disaccharide repeating unit (O unit) containingd-fucofuranose and 6-deoxy-d-manno-heptopyranose, as well as a minor 6-deoxy-3-O-methylhexose (most likely, 3-O-methylfucose). The O-antigen gene cluster ofE. coliO52, which is located between thegalFandgndgenes, was found to contain putative genes for the synthesis of the O-antigen constituents, sugar transferase genes, and ABC-2 transporter genes. Further analysis confirmed that O52 employs an ATP-binding cassette (ABC) transporter-dependent pathway for translocation and polymerization of the O unit. This is the first report of an ABC transporter being involved in translocation of a heteropolysaccharide O antigen inE. coli. Genes specific forE. coliO52 were also identified.
Phenylphosphate Carboxylase: a New C-C Lyase Involved in Anaerobic Phenol Metabolism in
Thauera aromatica
Authors: Schühle Karola , Fuchs Georg 
Published: July 2004

ABSTRACT

The anaerobic metabolism of phenol in the beta-proteobacterium
Thauera aromatica
proceeds via carboxylation to 4-hydroxybenzoate and is initiated by the ATP-dependent conversion of phenol to phenylphosphate. The subsequent
para
carboxylation of phenylphosphate to 4-hydroxybenzoate is catalyzed by phenylphosphate carboxylase, which was purified and studied. This enzyme consists of four proteins with molecular masses of 54, 53, 18, and 10 kDa, whose genes are located adjacent to each other in the phenol gene cluster which codes for phenol-induced proteins. Three of the subunits (54, 53, and 10 kDa) were sufficient to catalyze the exchange of
14
CO
2
and the carboxyl group of 4-hydroxybenzoate but not phenylphosphate carboxylation. Phenylphosphate carboxylation was restored when the 18-kDa subunit was added. The following reaction model is proposed. The
14
CO
2
exchange reaction catalyzed by the three subunits of the core enzyme requires the fully reversible release of CO
2
from 4-hydroxybenzoate with formation of a tightly enzyme-bound phenolate intermediate. Carboxylation of phenylphosphate requires in addition the 18-kDa subunit, which is thought to form the same enzyme-bound energized phenolate intermediate from phenylphosphate with virtually irreversible release of phosphate. The 54- and 53-kDa subunits show similarity to UbiD of
Escherichia coli
, which catalyzes the decarboxylation of a 4-hydroxybenzoate derivative in ubiquinone (
ubi
) biosynthesis. They also show similarity to components of various decarboxylases acting on aromatic carboxylic acids, such as 4-hydroxybenzoate or vanillate, whereas the 10-kDa subunit is unique. The 18-kDa subunit belongs to a hydratase/phosphatase protein family. Phenylphosphate carboxylase is a member of a new family of carboxylases/decarboxylases that act on phenolic compounds, use CO
2
as a substrate, do not contain biotin or thiamine diphosphate, require K
+
and a divalent metal cation (Mg
2+
or Mn
2+
) for activity, and are strongly inhibited by oxygen.
Mu-Like Prophage Strong Gyrase Site Sequences: Analysis of Properties Required for Promoting Efficient Mu DNA Replication
Authors: Oram Mark , Pato Martin L. 
Published: July 2004

ABSTRACT

The bacteriophage Mu genome contains a centrally located strong gyrase site (SGS) that is required for efficient prophage replication. To aid in studying the unusual properties of the SGS, we sought other gyrase sites that might be able to substitute for the SGS in Mu replication. Five candidate sites were obtained by PCR from Mu-like prophage sequences present in
Escherichia coli
O157:H7 Sakai,
Haemophilus influenzae
Rd,
Salmonella enterica
serovar Typhi CT18, and two strains of
Neisseria meningitidis
. Each of the sites was used to replace the natural Mu SGS to form recombinant prophages, and the effects on Mu replication and host lysis were determined. The site from the
E. coli
prophage supported markedly enhanced replication and host lysis over that observed with a Mu derivative lacking the SGS, those from the
N. meningitidis
prophages allowed a small enhancement, and the sites from the
Haemophilus
and
Salmonella
prophages gave none. Each of the candidate sites was cleaved specifically by
E. coli
DNA gyrase both in vitro and in vivo. Supercoiling assays performed in vitro, with the five sites or the Mu SGS individually cloned into a pUC19 reporter plasmid, showed that the Mu SGS and the
E. coli
or
N. meningitidis
sequences allowed an enhancement of processive, gyrase-dependent supercoiling, whereas the
H. influenzae
or
Salmonella
serovar Typhi sequences did not. While consistent with a requirement for enhanced processivity of supercoiling for a site to function in Mu replication, these data suggest that other factors are also important. The relevance of these observations to an understanding of the function of the SGS is discussed.
Bacillus subtilis
YdiH Is a Direct Negative Regulator of the
cydABCD
Operon
Authors: Schau Matthew , Chen Yinghua , Hulett F. Marion 
Published: July 2004

ABSTRACT

During aerobic respiration,
Bacillus subtilis
utilizes three terminal oxidases, cytochromes
aa
3
,
caa
3
, and
bd
. Cytochrome
bd
is encoded by the
cydABCD
operon. We report here the first identification of a regulator for the
cydABCD
operon, YdiH. While working with Δ
resDE
mutant strains, we identified colonies which contained suppressor mutations (
cmp
) which bypassed the requirement for ResD for all phenotypes not associated with cytochrome
aa
3
or
caa
3
. Mapping identified a class of Tn
10
insertions which were close to the
cmp
locus (Tn
10
-
2
) and a second class (Tn
10
-
1
) which was inserted in
cydD
, a gene which appears to be essential to the
cmp
phenotype. Sequencing of the
cmp
loci from four independent Δ
resDE cmp
isolates yielded four loss-of-function alleles of
ydiH
, a gene encoding a protein with homology to AT-rich DNA-binding proteins. Additionally, we determined that cytochrome
bd
was aberrantly expressed in the Δ
resDE cmp
background. Together these data led to the hypothesis that YdiH serves as a negative regulator of
cydABCD
expression, a hypothesis supported by both gel-shift and DNase I footprinting analyses. YdiH protected the
cydA
promoter region at three 22-bp repeats located in the long 5′ untranslated region (193 bp). Induction of the
cydABCD
operon in a Δ
resDE
background showed that expression of the terminal oxidase
bd
was responsible for the bypass phenotype observed in a Δ
resDE cmp
strain, indicating that cytochrome
bd
expression complemented the loss of cytochromes
aa
3
and
caa
3
in the Δ
resDE
strain.
P2 Growth Restriction on an
rpoC
Mutant Is Suppressed by Alleles of the
Rz1
Homolog
lysC
Authors: Markov Dmitry , Christie Gail E. , Sauer Brian , Calendar Richard , Park Taehyun , Young Ry , Severinov Konstantin 
Published: July 2004

ABSTRACT

Escherichia coli
strain 397c carries a temperature-sensitive mutation,
rpoC397
, that removes the last 50 amino acids of the RNA polymerase β′ subunit and is nonpermissive for plating of bacteriophage P2. P2
gor
mutants productively infect 397c and define a new gene,
lysC
, encoded by a reading frame that extensively overlaps the P2 lysis accessory gene,
lysB
. The unusual location of
lysC
with respect to
lysB
is reminiscent of the
Rz/Rz1
lysis gene pair of phage λ. Indeed, coexpression of
lysB
and
lysC
complemented the growth defect of λ
Rz
/
Rz1
null mutants, indicating that the LysB/C pair is similar to Rz/Rz1 in both gene arrangement and function. Cells carrying the
rpoC397
mutation exhibited an early onset of P2-induced lysis, which was suppressed by the
gor
mutation in
lysC
. We propose that changes in host gene expression resulting from the
rpoC397
mutation result in changes in the composition of the bacterial cell wall, making the cell more susceptible to P2-mediated lysis and preventing accumulation of progeny phage sufficient for plaque formation.
Differences in Membrane Fluidity and Fatty Acid Composition between Phenotypic Variants of
Streptococcus pneumoniae
Authors: Aricha Barak , Fishov Itzhak , Cohen Zvi , Sikron Noga , Pesakhov Stella , Khozin-Goldberg Inna , Dagan Ron , Porat Nurith 
Published: July 2004

ABSTRACT

Phase variation in the colonial opacity of
Streptococcus pneumoniae
has been implicated as a factor in the pathogenesis of pneumococcal disease. This study examined the relationship between membrane characteristics and colony morphology in a few selected opaque-transparent couples of
S. pneumoniae
strains carrying different capsular types. Membrane fluidity was determined on the basis of intermolecular excimerization of pyrene and fluorescence polarization of 1,6-diphenyl 1,3,5-hexatriene (DPH). A significant decrease, 16 to 26% (
P
≤ 0.05), in the excimerization rate constant of the opaque variants compared with that of the transparent variants was observed, indicating higher microviscosity of the membrane of bacterial cells in the opaque variants. Liposomes prepared from phospholipids of the opaque phenotype showed an even greater decrease, 27 to 38% (
P
≤ 0.05), in the pyrene excimerization rate constant compared with that of liposomes prepared from phospholipids of bacteria with the transparent phenotype. These findings agree with the results obtained with DPH fluorescence anisotropy, which showed a 9 to 21% increase (
P
≤ 0.001) in the opaque variants compared with the transparent variants. Membrane fatty acid composition, determined by gas chromatography, revealed that the two variants carry the same types of fatty acids but in different proportions. The trend of modification points to the presence of a lower degree of unsaturated fatty acids in the opaque variants compared with their transparent counterparts. The data presented here show a distinct correlation between phase variation and membrane fluidity in
S. pneumoniae
. The changes in membrane fluidity most probably stem from the observed differences in fatty acid composition.
Distribution, Genetic Diversity, and Variable Expression of the Gene Encoding Hyaluronate Lyase within theStreptococcus suisPopulation
Authors: King Samantha J. , Allen Andrew G. , Maskell Duncan J. , Dowson Christopher G. , Whatmore Adrian M. 
Published: July 2004

ABSTRACTAlthoughStreptococcus suisis an economically important pathogen of pigs and an occasional cause of zoonotic infections of humans knowledge of crucial virulence factors, and as a consequence targets for therapeutic or prophylactic intervention, remains limited. Here we describe a detailed study of the distribution, diversity, and in vitro expression of hyaluronate lyase, a protein implicated as a virulence factor of many mucosal pathogens. The gene encoding hyaluronate lyase,hyl, was present in all 309 bona fideS. suisisolates examined representing diverse serotypes, geographic sources, and clinical backgrounds. Examination of the genetic diversity ofhylby RFLP and sequence analysis indicated a pattern of diversity shared by many gram-positive surface proteins with a variable 5′ region encoding the most distal cell surface-exposed regions of the protein and a much more conserved 3′ region encoding domains more closely associated with the bacterial cell. Variation occurs by several mechanisms, including the accumulation of point mutations and deletion and insertion events, and there is clear evidence that genetic recombination has contributed to molecular variation in this gene. Despite the ubiquitous presence ofhyl, the corresponding enzyme activity was detected in fewer than 30% of the 309 isolates. In several cases this lack of activity correlates with the presence of mutations (either sequence duplications or point mutations) withinhylthat result in a truncated polypeptide. There is a striking absence of hyaluronate lyase activity in a large majority of isolates from classicS. suisinvasive disease, indicating that this protein is probably not a crucial virulence factor, although activity is present in significantly higher numbers of isolates associated with pneumonia.
Identification of a Broadly Active Phage Lytic Enzyme with Lethal Activity against Antibiotic-Resistant
Enterococcus faecalis
and
Enterococcus faecium
Authors: Yoong Pauline , Schuch Raymond , Nelson Daniel , Fischetti Vincent A. 
Published: July 2004

ABSTRACT

Enterococcus faecalis
and
Enterococcus faecium
infections are increasingly difficult to treat due to high levels of resistance to antibiotics. PlyV12, a bacteriophage lytic enzyme, was isolated and shown to effectively kill both
E. faecalis
and
E. faecium
(including vancomycin-resistant strains), as well as other human pathogens. We propose its development and use as an alternative therapeutic tool.
Whole-Genome Expression Profiling of
Thermotoga maritima
in Response to Growth on Sugars in a Chemostat
Authors: Nguyen Tu N. , Ejaz Arvin D. , Brancieri Mark A. , Mikula Amy M. , Nelson Karen E. , Gill Steven R. , Noll Kenneth M. 
Published: July 2004

ABSTRACT

To provide data necessary to study catabolite-linked transcriptional networks in
Thermotoga maritima
, we used full-genome DNA microarray analysis of global transcriptional responses to growth on glucose, lactose, and maltose in a chemostat. A much larger number of genes changed expression in cells grown on lactose than on maltose, each relative to genes expressed in cells grown on glucose. Genes encoding putative oligopeptide transporters were often coregulated with adjacent glycosidase-encoding genes. Genes encoding enzymes catalyzing NADH oxidation were up-regulated on both lactose and maltose. Genes involved in iron and sulfur metabolism were differentially expressed in response to lactose. These data help define the sets of coregulated genes and suggest possible functions for their encoded products.
Negotiation Support Systems: Communication and Information as Antecedents of Negotiation Settlement
Authors: Neijens Peter , Swaab Roderick , Postmes Tom 
Published: July 2004

AbstractInnovative approaches such as the use of technology in negotiations raise questions of how technology interacts with the manifold contextual factors that play a role in negotiations. In this article, we introduce a theoretical framework that seeks to inform the design of Negotiation Support Systems (NSS) by focusing on two antecedents of negotiation success. On the one hand, we argue that NSS should stimulate a common (cultural) identity among the individual negotiators, a strong predictor of integrative agreements in prior research. On the other hand, NSS should seek to provide information in order to develop shared cognition among negotiators. Negotiators' perceptions of the problem at hand and possible solutions often diverge significantly as a consequence of their different knowledge and motives. In this article, we report some experimental support for this framework. We conclude that shared identity and shared cognition are relatively powerful predictors of outcomes of international negotiations, and that minimal variations in the configuration of an NSS can have strong effects on these results.