bluuebunny/crossref_metadata_2025 huggingface dataset:
CovR Activation of the Dipeptide Permease Promoter (PdppA) in Group A Streptococcus
Authors: Gusa Asiya A. , Froehlich Barbara J. , Desai Devak , Stringer Virginia , Scott June R.
Published: February 2007

CovR, the two-component response regulator ofStreptococcus pyogenes(group A streptococcus [GAS]) directly or indirectly represses about 15% of the genome, including genes encoding many virulence factors and itself. Transcriptome analyses also showed that some genes are activated by CovR. We asked whether the regulation by CovR of one of these genes,dppA, the first gene in an operon encoding a dipeptide permease, is direct or indirect. Direct regulation by CovR was suggested by the presence of five CovR consensus binding sequences (CBs) near the putative promoter. In this study, we identified the 5′ end of thedppAtranscript synthesized in vivo and showed that the start ofdppAtranscription in vitro is the same. We found that CovR binds specifically to thedppApromoter region (PdppA) in vitro with an affinity similar to that at which it binds to other CovR-regulated promoters. Disruption of any of the five CBs by a substitution of GG for TT inhibited CovR binding to that site in vitro, and binding at two of the CBs appeared cooperative. In vivo, CovR activation of transcription was not affected by individual mutations of any of the four CBs that we could study. This suggests that the binding sites are redundant in vivo. In vitro, CovR did not activate transcription from PdppAin experiments using purified GAS RNA polymerase and either linear or supercoiled DNA template. Therefore, we propose that in vivo, CovR may interfere with the binding of a repressor of PdppA.
Group B Streptococcal Pilus Proteins Contribute to Adherence to and Invasion of Brain Microvascular Endothelial Cells
Authors: Maisey Heather C. , Hensler Mary , Nizet Victor , Doran Kelly S.
Published: February 2007

Surface filamentous structures known as pili have been discovered recently in the gram-positive streptococcal pathogens that cause invasive disease in humans, including group B
Streptococcus
(GBS). We show that two GBS proteins involved in pilus formation, encoded by
pilA
and
pilB
, also facilitate the interaction of this important agent of central nervous system infection with endothelial cells of the human blood-brain barrier.
Competence-Dependent Bacteriocin Production by
Streptococcus gordonii
DL1 (Challis)
Authors: Heng Nicholas C. K. , Tagg John R. , Tompkins Geoffrey R.
Published: February 2007

The production of streptocins STH
1
and STH
2
by
Streptococcus gordonii
DL1 (Challis) is directly controlled by the competence regulon, which requires intact
comR
and
comAB
loci. The streptocin (
sth
) locus comprises two functional genes,
sthA
and
sthB
. Whereas STH
1
activity requires
sthA
alone, STH
2
activity depends on both genes.
The Gene Cluster for Agmatine Catabolism ofEnterococcus faecalis: Study of Recombinant Putrescine Transcarbamylase and Agmatine Deiminase and a Snapshot of Agmatine Deiminase Catalyzing Its Reaction
Authors: Llácer José L. , Polo Luis Mariano , Tavárez Sandra , Alarcón Benito , Hilario Rebeca , Rubio Vicente
Published: February 2007

Enterococcus faecalismakes ATP from agmatine in three steps catalyzed by agmatine deiminase (AgDI), putrescine transcarbamylase (PTC), and carbamate kinase (CK). An antiporter exchanges putrescine for agmatine. We have cloned theE. faecalisef0732 and ef0734 genes of the reported gene cluster for agmatine catabolism, overexpressed them inEscherichia coli, purified the products, characterized them functionally as PTC and AgDI, and crystallized and X-ray diffracted them. The 1.65-Å-resolution structure of AgDI forming a covalent adduct with an agmatine-derived amidine reactional intermediate is described. We provide definitive identification of the gene cluster for agmatine catabolism and confirm that ornithine is a genuine but poor PTC substrate, suggesting that PTC (found here to be trimeric) evolved from ornithine transcarbamylase.N-(Phosphonoacetyl)-putrescine was prepared and shown to strongly (Ki= 10 nM) and selectively inhibit PTC and to improve PTC crystallization. We find thatE. faecalisAgDI, which is committed to ATP generation, closely resembles the AgDIs involved in making polyamines, suggesting the recruitment of a polyamine-synthesizing AgDI into the AgDI pathway. The arginine deiminase (ADI) pathway of arginine catabolism probably supplied the genes for PTC and CK but not those for the agmatine/putrescine antiporter, and thus the AgDI and ADI pathways are not related by a single “en bloc” duplication event. The AgDI crystal structure reveals a tetramer with a five-blade propeller subunit fold, proves that AgDI closely resembles ADI despite a lack of sequence identity, and explains substrate affinity, selectivity, and Cys357-mediated-covalent catalysis. A three-tongued agmatine-triggered gating opens or blocks access to the active center.
Evaluation of Different PCR Assays for Early Detection of Acute and Relapsing Brucellosis in Humans in Comparison with Conventional Methods
Authors: Mitka Stella , Anetakis Constantine , Souliou Efimia , Diza Eudoxia , Kansouzidou Athina
Published: February 2007

Human brucellosis is a significant public health problem in many Mediterranean countries including Greece. The conventional serological methods, as well as blood cultures, have serious limitations, especially in chronic, relapsing, and focal forms of the disease. Four different PCR assays were applied in 4,926 buffy coat, whole-blood, and serum samples received from 200 patients admitted with brucellosis to the Infectious Diseases Hospital, Thessaloniki, Greece, for the rapid diagnosis of acute infection and relapses and compared to blood culture and serological tests (i.e., Wright's seroagglutination test, Coombs' antibrucella test, and the complement fixation test). The four PCR assays had excellent sensitivity and specificity and were able to detect all of the cases of acute disease. Buffy coat and whole blood were the optimal specimens. All four PCR assays were negative in all follow-up samples from 183 patients who had completed a successful treatment and were positive in all follow-up samples from 17 patients who had relapses in the first year after therapy, including the times of the relapses. In conclusion, PCR is a very useful tool for the rapid diagnosis of acute brucellosis and a good marker for the posttreatment follow-up and the early detection of relapses.
Multicenter Evaluation of the New VITEK 2 Advanced Colorimetric Yeast Identification Card
Authors: Hata D. Jane , Hall Leslie , Fothergill Annette W. , Larone Davise H. , Wengenack Nancy L.
Published: February 2007

The performance of the new VITEK 2 Advanced Colorimetry yeast identification (YST) card for use with the VITEK 2 system (bioMérieux, Inc., Hazelwood, MO) was compared to that of the API 20C AUX (API) system (bioMérieux SA, Marcy-l'Etoile, France) in a multicenter evaluation. A total of 12 quality control, 64 challenge, and 623 clinical yeast isolates were used in the study. Comparisons of species identification, platform reliability, and substrate reproducibility were made between YST and API, with API considered the reference standard. Quality control testing to assess system and substrate reproducibility matched expected results ≥95% of the time. The YST card correctly identified 100% of the challenge strains, which covered the species range of the manufacturer's performance claims. Using clinical isolates, the YST card correctly identified 98.5%, with 1.0% of isolates incorrectly identified and 0.5% unidentified. Among clinical isolates, the YST card generated fewer low-discrimination results (18.9%) than did API (30.0%). The time to identification with YST was 18 h, compared to 48 to 72 h with API. The colorimetric YST card used with the VITEK 2 provides a highly automated, objective yeast identification method with excellent performance and reproducibility. We found this system useful for timely and accurate identification of significant yeast species in the clinical microbiology laboratory.
Methicillin-ResistantStaphylococcus pseudintermediusin a Veterinary Teaching Hospital
Authors: Sasaki Takashi , Kikuchi Ken , Tanaka Yoshikazu , Takahashi Namiko , Kamata Shinichi , Hiramatsu Keiichi
Published: February 2007

We surveyed methicillin-resistant coagulase-positive staphylococcus (MRCPS) strains from 57 (26 inpatient and 31 outpatient) dogs and 20 veterinary staff in a veterinary teaching hospital. From the staff, three MRCPS strains were isolated, and two were methicillin-resistantStaphylococcus aureus(MRSA). In contrast, 18 MRCPS strains were detected in both inpatient (12 of 26 [46.2%]) and outpatient (6 of 31 [19.4%]) dogs. Among them, only one strain was MRSA. Using direct sequencing ofsodAandhsp60genes, the 18 MRCPS strains other than MRSA from a staff and 17 dogs, were finally identified asStaphylococcus pseudintermedius, a novel species ofStaphylococcusfrom a cat. All of the methicillin-resistantS. pseudintermedius(MRSP) strains were multidrug resistant to erythromycin, clindamycin, trimethoprim-sulfamethoxazole, and levofloxacin. Most of the MRSP strains showed high-level resistance to oxacillin (≥128 μg/ml, 15 of 18 [83.3%]), and 10 of 15 (66.7%) high-level oxacillin-resistant MRSP strains carried type III SCCmec. DNA fingerprinting of MRSP strains by pulsed-field gel electrophoresis yielded eight clusters: clone A with four subtypes, clone B with four subtypes, clone C with three subtypes, and five other different single clones. MRSP strains from the staff and some inpatient and outpatient dogs shared three major clones (clones A, B, and C), but the strains of the other five different clusters were distributed independently among inpatient or outpatient dogs. This genetic diversity suggested that the MRSP strains were not only acquired in this veterinary teaching hospital but also acquired in primary veterinary clinics in the community. To our knowledge, this is the first report of MRSP in dogs and humans in a veterinary institution.
Role of the Transmembrane Domain of Marburg Virus Surface Protein GP in Assembly of the Viral Envelope
Authors: Mittler Eva , Kolesnikova Larissa , Strecker Thomas , Garten Wolfgang , Becker Stephan
Published: February 2007

The major protein constituents of the filoviral envelope are the matrix protein VP40 and the surface transmembrane protein GP. While VP40 is recruited to the sites of budding via the late retrograde endosomal transport route, GP is suggested to be transported via the classical secretory pathway involving the endoplasmic reticulum, Golgi apparatus, and
trans
-Golgi network until it reaches the plasma membrane where most filoviral budding takes place. Since both transport routes target the plasma membrane, it was thought that GP and VP40 join there to form the viral envelope. However, it was recently shown that, upon coexpression of both proteins, GP is partially recruited into peripheral VP40-enriched multivesicular bodies, which contained markers of the late endosome. Accumulation of GP and VP40 in this compartment was presumed to play an important role in the formation of the filoviral envelope. Using a domain-swapping approach, we were able to show that the transmembrane domain of GP was essential and sufficient for (i) partial recruitment of chimeric glycoproteins into VP40-enriched multivesicular bodies and (ii) incorporation into virus-like particles (VLPs) that were released upon expression of VP40. Only those chimeric glycoproteins which were targeted to VP40-enriched endosomal multivesicular bodies were subsequently recruited into VLPs. These data show that the transmembrane domain of GP is critical for the mixing of VP40 and GP in multivesicular bodies and incorporation of GP into the viral envelope. Results further suggest that trapping of GP in the VP40-enriched late endosomal compartment is important for the formation of the viral envelope.
Transcriptional Coactivator LEDGF/p75 Modulates Human Immunodeficiency Virus Type 1 Integrase-Mediated Concerted Integration
Authors: Pandey Krishan K. , Sinha Sapna , Grandgenett Duane P.
Published: February 2007

Human transcriptional coactivator p75/lens epithelium-derived growth factor (LEDGF) binds human immunodeficiency virus type 1 (HIV-1) integrase (IN). We studied the effects of LEDGF on the assembly and activity of HIV-1 synaptic complexes, which, upon association with a target, mediate concerted integration of viral DNA substrates in vitro. We found that while augmenting single-ended viral DNA integration into target DNA, the host factor was able to either stimulate or abrogate concerted integration in a concentration-dependent manner. LEDGF modestly stimulated (two- to threefold) concerted integration at low molar ratios to IN (<1). The modest stimulation was independent of solution conditions and several different viral DNA substrates. In solution, concerted integration was inhibited if the molar ratios of LEDGF to IN were >1, apparently due to the disruption of IN-IN interactions essential for the formation of active synaptic complexes prior to their association with a circular target. The isolated IN binding domain of LEDGF was sufficient to stimulate and inhibit concerted integration, as observed with full-length protein, albeit at lower efficiencies. Our data show that LEDGF differentially affects IN-DNA complexes mediating single-ended viral DNA integration and synaptic complexes mediating concerted integration. Synaptic complexes associated with target, termed strand transfer complexes, are resistant to disruption by high concentrations of LEDGF. The results suggest that LEDGF may influence HIV-1 integration in vivo.
Antigenic and Immunogenic Study of Membrane-Proximal External Region-Grafted gp120 Antigens by a DNA Prime-Protein Boost Immunization Strategy
Authors: Law Mansun , Cardoso Rosa M. F. , Wilson Ian A. , Burton Dennis R.
Published: February 2007

The membrane-proximal external region (MPER) of human immunodeficiency virus type 1 (HIV-1) gp41 is a target of broadly neutralizing monoclonal antibodies (MAbs) 2F5, 4E10, and Z13. Here we engrafted the MPER into the V1/2 region of HIV-1 gp120 to investigate the ability of the engineered antigens to elicit virus-neutralizing antibodies (NAbs). To promote the correct folding and presentation of the helical 4E10 epitope, we flanked the epitope with helical domains and manipulated the helix by sequential deletion of residues preceding the epitope. Binding of the recombinant proteins to MAb 4E10 increased four- to fivefold with the deletion of one or two residues, but it returned to the wild-type level when three residues were deleted, suggesting rotation of the 4E10 epitope along the helix. Immunization of mice and rabbits by electroporation-mediated DNA priming and protein boosting with these constructs elicited high levels of gp120-specific antibodies. A consistent NAb response against the neutralization-resistant, homologous JR-FL virus was detected in rabbits but not in mice. Analysis of the neutralizing activity revealed that the NAbs do not target the MPER or the V1, V2, or V3 region. Through this study, we learned the following. (i) The 4E10 epitope can be manipulated using a “rotate-the-helix” strategy that alters the helix register. However, presentation of this epitope in the immunogenic V1/2 region did not render it immunogenic in mice or rabbits. (ii) DNA vaccination with monomeric gp120-based antigens can elicit a consistent NAb response against the homologous neutralization-resistant virus by targeting epitopes outside the V1, V2, and V3 regions.
Identification of Amino Acid Residues in APOBEC3G Required for Regulation by Human Immunodeficiency Virus Type 1 Vif and Virion Encapsidation
Authors: Huthoff Hendrik , Malim Michael H.
Published: February 2007

The human immunodeficiency virus type-1 (HIV-1) accessory protein Vif serves to neutralize the human antiviral proteins apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like 3G (APOBEC3G [A3G]) and A3F. As such, the therapeutic blockade of Vif function represents a logical objective for rational drug design. To facilitate such endeavors, we have employed molecular genetics to define features of A3G that are required for its interaction with Vif. Using alanine-scanning mutations and multiple different substitutions at key residues, we confirm the central role played by the aspartic acid at position 128 and identify proline 129 and aspartic acid 130 as important contributory residues. The overall negative charge of this 3-amino-acid motif appears critical for recognition by Vif, as single lysine substitutions are particularly deleterious and a double alanine substitution at positions 128 and 130 is far more inhibitory than single-residue mutations at either position. Our analyses also reveal that the immediately adjacent 4 amino acids, residues 124 to 127, are important for the packaging of A3G into HIV-1 particles. Most important are tyrosine 124 and tryptophan 127, and mutations at these positions can ablate virion incorporation, as well as the capacity to inhibit virus infection. Thus, while pharmacologic agents that target the acidic motif at residues 128 to 130 have the potential to rescue A3G expression by occluding recognition by Vif, care will have to be taken not to perturb the contributions of the neighboring 124-to-127 region to packaging if such agents are to have therapeutic benefit by promoting A3G incorporation into progeny virions.
Management of patients with HBeAg-negative chronic hepatitis B
Authors: Saikia Nripen , Talukdar Rupjyoti , Mazumder Subhasish , Khanna Sudeep , Tandon Rakesh
Published: February 2007

Chronic hepatitis B (CHB) is one of the leading causes of morbidity and mortality worldwide. Although various drugs are available for the treatment of CHB, emergence of the hepatitis B e antigen (HBeAg)-negative mutant variant, specifically in Asia, the Middle East and southern Europe, is creating a new challenge as this variant is less responsive to available treatments. HBeAg-negative CHB rapidly progresses to cirrhosis and its related complications. This review discusses the available literature on the approved and under-trial treatment options and their respective efficacies for HBeAg-negative CHB.
Basal thumb arthritis
Authors: Dias Richard , Chandrasenan Jeevan , Rajaratnam Vaikunthan , Burke Frank D
Published: February 2007

Basal thumb arthritis is a common condition seen in hand clinics across the United Kingdom and is often associated with other pathological conditions such as carpal tunnel syndrome and scaphotrapezial arthritis. Typically, patients complain of pain localised to the base of the thumb. This pain is often activity related, particularly after excessive use involving forceful pinch. A detailed history and examination is normally all that is needed to make the diagnosis. Provocative manoeuvres may be helpful in localising symptoms to the basal joint with degenerative changes or synovitis. Radiographs are useful for confirming the diagnosis and staging the disease in order to plan for surgery. The mainstay of initial treatment of basal thumb arthritis of any stage is activity modifications, rest, nonsteroidal anti-inflammatory drugs, exercises and splinting. A variety of surgical procedures are available to treat the condition when conservative measures have failed, in order to control symptoms and improve function. We review the current literature and discuss the clinical aspects of this condition, staging, and treatment options available, and the difficulties treating this group of patients.
Views of specialist registrars on specialty care in the community: employment prospects and the need for additional training
Authors: Azam N , Moshkovska T , Mayberry J F
Published: February 2007

Aim

To obtain the views of specialist registrars on specialty care in the community.

Method

Specialist registrars from five Deaneries in England completed an online questionnaire about their views on employment prospects, the role of specialty care in the community, and the need for additional training in this area.

Results

One hundred and twenty seven replies were received over a four week period. Thirty (24%) viewed their future employment prospects as consultants as poor or very worrying. Seventy seven (61%) specialist registrars considered that as consultants they will need to work directly in the community. Thirty nine of these (51%) considered the need to work close to patients directly in the community as either a “bad” or “very bad” development. However, 102 (80%) specialist registrars believed that they should receive training on the delivery of specialty care in the community and 96 (76%) wanted this in the form of a university based degree.
CLUSTERING OF STORED MEMORIES IN AN ATTRACTOR NETWORK WITH LOCAL COMPETITION
Authors: JOHANSSON CHRISTOPHER , EKEBERG ÖRJAN , LANSNER ANDERS
Published: February 2007

In this paper we study an attractor network with units that compete locally for activation and we prove that a reduced version of it has fixpoint dynamics. An analysis, complemented by simulation experiments, of the local characteristics of the network's attractors with respect to a parameter controlling the intensity of the local competition is performed. We find that the attractors are hierarchically clustered when the parameter of the local competition is changed.
COMPUTER SIMULATION STUDY ON CENTRAL PATTERN GENERATOR: FROM BIOLOGY TO ENGINEERING
Authors: ZHANG DINGGUO , ZHU KUANYI
Published: February 2007

Central pattern generator (CPG) is a neuronal circuit in the nervous system that can generate oscillatory patterns for the rhythmic movements. Its simplified format, neural oscillator, is wildly adopted in engineering application. This paper explores the CPG from an integral view that combines biology and engineering together. Biological CPG and simplified CPG are both studied. Computer simulation reveals the mechanism of CPG. Some properties, such as effect of tonic input and sensory feedback, stable oscillation, robustness, entrainment etc., are further studied. The promising results provide foundation for the potential engineering application in future.
CARCINOGENESIS AS AN EVOLUTIONARY GAME
Authors: VINCENT THOMAS L.
Published: February 2007

Human cancer may be thought of as Darwinian evolution of cells within the body (somatic evolution). As such, it may be modeled using evolutionary game theory. Winners in this game are able to maintain viable population numbers while losers go extinct. A model for somatic evolution is presented that shows how cancer can evolve to become a winner in this game. Associated with the model is an adaptive landscape that illustrates the evolutionary potential of cells as a function of adaptive parameters used by cells. Normal cells have a novel adaptive landscape that permits coexistence of invading mutant phenotypes. A mutant cellular population needs not immediately form a malignancy due to the existence of cellular constraints that results in limited growth and non-lethal coexistence. However, this coexistence deforms the local adaptive landscape resulting in an unoccupied fitness peak. The existence of this peak provides the potential for evolution to drive the mutant cells from simple coexistence to an evasive cancer. The model presented here suggests all that is required to accomplish this result is the relaxation of constraints that normally prohibit cells to evolve.
Altered protein expression at early-stage rat hepatic neoplasia
Authors: Luo Qilie , Siconolfi-Baez Linda , Annamaneni Pallavi , Bielawski Mark T. , Novikoff Phyllis M. , Angeletti Ruth Hogue
Published: February 2007

Protein expression patterns were analyzed in a rat model of hepatic neoplasia to detect changes reflecting biological mechanism or potential therapeutic targets. The rat resistant hepatocyte model of carcinogenesis was studied, with a focus on the earliest preneoplastic lesion visible in the liver, the preneoplastic hyperplastic nodule. Expression differences were shown by two-dimensional polyacrylamide gel electrophoresis and image analysis. Polypeptide masses were measured by peptide mass fingerprinting using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF) and their sequences were obtained by tandem mass spectrometry. Alterations in expression of cytoskeletal and functional proteins were demonstrated, consistent with biological changes known to occur in the preneoplastic cells. Of particular interest was the differential expression of a serine protease inhibitor (serpin) with a role implicated in angiogenesis. Serpin, implicated in the inhibition of angiogenesis, is present in normal liver but has greatly reduced expression at the preneoplastic stage of liver cancer development. Immunofluorescence microscopy with antibodies to this serpin, kallistatin, supports the proteomic identification. Immunofluorescence microscopy with antibodies to the blood vessel marker von Willebrand factor provides evidence for neovascularization in the liver containing multiple preneoplastic nodules. These observations suggest that at an early stage of liver carcinogenesis reduction or loss of angiogenesis inhibitors may contribute to initiation of neoangiogenesis. A number of other identified proteins known to be associated with hepatomas are also present at early-stage neoplasia.
Endothelial function across an oral contraceptive cycle in women using levonorgestrel and ethinyl estradiol
Authors: Torgrimson Britta N. , Meendering Jessica R. , Kaplan Paul F. , Minson Christopher T.
Published: February 2007

Oral contraceptive pills (OCPs) are a popular contraception method. Currently, lower-dose ethinyl estradiol formulations are most commonly prescribed, although they have been linked to increased arterial vascular risk. The aim of this study was to investigate endothelial function in healthy young women using lower-dose ethinyl estradiol OCPs. We examined flow-mediated, endothelium-dependent and nitroglycerin-mediated, endothelium-independent vasodilation of the brachial artery, comparing two doses of ethinyl estradiol/levonorgestrel OCPs in 15 healthy young women on two study days: once during the active phase and once during the placebo phase of an OCP cycle. Group low dose (LD) ( n = 7) active pills contained 150 μg levonorgestrel/30 μg ethinyl estradiol versus Group very low dose (VLD) ( n = 8) with 100 μg levonorgestrel/20 μg ethinyl estradiol. Endothelium-dependent vasodilation was lower during the active phase in Group VLD (5.33 ± 1.77% vs. 7.23 ± 2.60%; P = 0.024). This phase difference was not observed in Group LD (8.00 ± 0.970% vs. 7.61 ± 1.07%; P = 0.647). Endothelium-independent vasodilation did not differ between phases in either group. Finally, we measured endothelium-dependent vasodilation in two additional women who received 10 μg of unopposed ethinyl estradiol. Endothelium-dependent vasodilation was increased by unopposed ethinyl estradiol compared with the placebo phase (10.88 ± 2.34% vs. 6.97 ± 1.83%). These results suggest that levonorgestrel may antagonize the activity of ethinyl estradiol. Thus both the progestin type and estradiol dose need to be considered when assessing arterial vascular risk of OCP use in women.
Speckle-tracking echocardiography correctly identifies segmental left ventricular dysfunction induced by scarring in a rat model of myocardial infarction
Authors: Popović Zoran B. , Benejam Carlos , Bian Jing , Mal Niladri , Drinko Jeannie , Lee Kwangdeok , Forudi Farhad , Reeg Rachel , Greenberg Neil L. , Thomas James D. , Penn Marc S.
Published: February 2007

Speckle-tracking echocardiography (STE) uses a two-dimensional echocardiographic image to estimate two orthogonal strain components. The aim of this study was to assess sensitivity of circumferential (Scirc) and radial (Srad) strains to infarct-induced left ventricular (LV) remodeling and scarring of the LV in a rat. To assess the relationship among Scirc, Srad, and scar size, two-dimensional echocardiographic LV short-axis images (12 MHz transducer, Vivid 7 echo machine) were collected in 34 Lewis rats 4 to 10 wk after ligation of the left anterior descending artery. Percent segmental fibrosis was assessed from histological LV cross sections stained by Masson trichrome. Ten normal rats served as echocardiographic controls. Scirc and Srad were assessed by STE. Histological data showed consistent scarring of anterior and lateral segments with variable extension to posterior and inferior segments. Both Scirc and Srad significantly decreased after myocardial infarction ( P < 0.0001 for both). As anticipated, Scirc and Srad were lowest in the infarcted segments. Multiple linear regression showed that segmental Scirc were similarly dependent on segmental fibrosis and end-systolic diameter ( P < 0.0001 for both), whereas segmental Srad measurements were more dependent on end-systolic diameter ( P < 0.0001) than on percent fibrosis ( P < 0.002). STE correctly identifies segmental LV dysfunction induced by scarring that follows myocardial infarction in rats.
Prevention of pressure-induced deep tissue injury using intermittent electrical stimulation
Authors: Solis Leandro R. , Hallihan Daniel P. , Uwiera Richard R. E. , Thompson Richard B. , Pehowich Enid D. , Mushahwar Vivian K.
Published: February 2007

Pressure ulcers develop due to morphological and biochemical changes triggered by the combined effects of mechanical deformation, ischemia, and reperfusion that occur during extended periods of immobility. The goal of this study was to test the effectiveness of a novel electrical stimulation technique in the prevention of deep tissue injury (DTI). We propose that contractions elicited by intermittent electrical stimulation (IES) in muscles subjected to constant pressure would induce periodic relief in internal pressure; additionally, each contraction would also restore blood flow to the tissue. The application of constant pressure to the quadriceps muscles of rats generated a DTI that affected 60 ± 15% of the compressed muscle as assessed by magnetic resonance imaging. In contrast, in the groups of rats that received IES at 10- and 5-min intervals, DTI of the muscle was limited to 16 ± 16 and 25 ± 13%, respectively. Injury to the muscle was corroborated by histology. In an experiment with a human volunteer, compression of the buttocks reduced the oxygenation level of the muscles by ∼4%; after IES, oxygenation levels increased by ∼6% beyond baseline. Concurrently, the surface pressure profiles of the loaded muscles were redistributed and the high-pressure points were reduced during each IES-induced contraction. The results of this study indicate that IES significantly reduces the amount of DTI by increasing the oxygen available to the tissue and by modifying the pressure profiles of the loaded muscles. This presents a promising technique for the prevention of pressure ulcers in immobilized and/or insensate individuals.
Reducing susceptibility to bacteremia after experimental burn injury: a role for selective decontamination of the digestive tract
Authors: Horton Jureta W. , Maass David L. , White Jean , Minei Joseph P.
Published: February 2007

We proposed that selective decontamination of the digestive tract (SDD) initiated after experimental burn injury would decrease myocardial inflammation and dysfunction after a second insult such as septic challenge. Rats were divided into eight experimental groups. Groups included sham burn plus sham sepsis, burn alone, sepsis alone, and burn plus sepsis given either water by oral gavage for 5 days after burn (or sham burn) or given oral antibiotics (polymyxin E, 15 mg; tobramycin, 6 mg; 5-flucytosin, 100 mg given by oral gavage, 2× daily for 5 days after burn or sham burn). Cardiac function and inflammation were studied 24 h after septic challenge. In the absence of SDD, burn alone, sepsis alone, or burn plus septic challenge promoted cardiac myocyte secretion of TNF-α (burn, 174 ± 11; sepsis, 269 ± 19; burn + sepsis, 453 ± 14 pg/ml), IL-1β (burn, 35 ± 2; sepsis, 29 ± 1; burn + sepsis, 48 ± 7 pg/ml), and IL-6 (burn, 143 ± 18; sepsis, 116 ± 3; burn + sepsis, 248 ± 12 pg/ml) compared with values measured in sham (TNF-α, 3 ± 1; IL-1β, 1 ± 0.4; IL-6, 6 ± 1.5 pg/ml) ( P < 0.05). Impaired ventricular contraction and relaxation responses were evident in the absence of SDD [burn + sepsis: left ventricular pressure (LVP), 65 ± 4 mmHg; rate of LVP rise (+dP/d t), 1,320 ± 131 mmHg/s compared with values measured in sham: LVP, 96 ± 4 mmHg; +dP/d t, 2,095 ± 99 mmHg/s, P < 0.05]. SDD treatment of experimental burn attenuated septic challenge-related inflammatory responses and improved myocardial contractile responses, producing cardiac TNF-α, IL-1β, and IL-6 levels, LVP, +dP/d t, and rate of LVP fall (−dP/d t) values that were significantly better ( P < 0.05) than values measured in burn plus sepsis in the absence of SDD. This work confirms that endogenous gut organisms contribute to sensitivity to subsequent infectious challenge.
Inhibition of fibroblast to myofibroblast transition by halofuginone contributes to the chemotherapy-mediated antitumoral effect
Authors: Sheffer Yuval , Leon Oded , Pinthus Jehonathan H. , Nagler Arnon , Mor Yoram , Genin Olga , Iluz Maya , Kawada Norifumi , Yoshizato Katsutoshi , Pines Mark
Published: February 2007

Stromal myofibroblasts play an important role in tumor progression. The transition of fibroblasts to myofibroblasts is characterized by expression of smooth muscle genes and profuse synthesis of extracellular matrix proteins. We evaluated the efficacy of targeting fibroblast-to-myofibroblast transition with halofuginone on tumor progression in prostate cancer and Wilms' tumor xenografts. In both xenografts, low doses of halofuginone treatment, independent of the route of administration, resulted in a trend toward inhibition in tumor development. Moreover, halofuginone synergizes with low dose of docetaxel in prostate cancer and vincristine and dactinomycin in Wilms' tumor xenografts, resulting in significant reduction in tumor volume and weight comparable to the effect observed by high doses of the respective chemotherapies. In prostate cancer and Wilms' tumor xenografts, halofuginone, but not the respective chemotherapies, inhibited the synthesis of collagen type I, α-smooth muscle actin, transgelin, and cytoglobin, all of which are characteristics of activated myofibroblasts. Halofuginone, as the respective chemotherapies, increased the synthesis of Wilms' tumor suppressor gene product (WT-1) and prostate apoptosis response gene-4 (Par-4), resulting in apoptosis/necrosis. These results suggest that targeting the fibroblast-to-myofibroblast transition with halofuginone may synergize with low doses of chemotherapy in achieving a significant antitumoral effect, avoiding the need of high-dose chemotherapy and its toxicity without impairing treatment efficacy. [Mol Cancer Ther 2007;6(2)570–7
Identification of Soluble Tumor Necrosis Factor-Like Weak Inducer of Apoptosis (sTWEAK) as a Possible Biomarker of Subclinical Atherosclerosis
Authors: Blanco-Colio Luis M. , Martín-Ventura Jose L. , Muñóz-García Begoña , Orbe Josune , Páramo Jose A. , Michel Jean-Baptiste , Ortiz Alberto , Meilhac Olivier , Egido Jesús
Published: February 2007

Objectives—

Assessment of vascular risk in asymptomatic patients and the response to medical therapy is a major challenge for prevention of cardiovascular events. Our aim was to identify proteins differentially released by healthy versus atherosclerotic arterial walls, which could be found in plasma and serve as markers of atherosclerosis.

Methods and Results—

We have analyzed supernatants obtained from cultured human carotid plaques and healthy arteries by surface-enhanced laser-desorption/ionization time-of-flight mass spectrometry ProteinChip System. Surface-enhanced laser-desorption/ionization analysis unveiled an 18.4-kDa peak released in lower amount by carotid plaques than normal endarteries. This protein was identified as soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK). To confirm that sTWEAK was the protein of interest, Western blot and enzyme-linked immunosorbent assay were performed. Both techniques confirmed that sTWEAK levels were decreased in carotid plaque supernatants. Subsequent measurement of sTWEAK in plasma showed a reduced concentration in subjects with carotid stenosis (N=30) compared with healthy subjects matched by sex and age (N=28) (
P
<0.001). Furthermore, in a test population of 106 asymptomatic subjects, we showed that sTWEAK concentrations negatively correlated with the carotid intima-media thickness (
r
=−0.4;
P
<0.001), an index of subclinical atherosclerosis.

Conclusions—

These results suggest that sTWEAK could be a potential biomarker of atherosclerosis.
Reconstituted High-Density Lipoprotein Stimulates Differentiation of Endothelial Progenitor Cells and Enhances Ischemia-Induced Angiogenesis
Authors: Sumi Makoto , Sata Masataka , Miura Shin-ichiro , Rye Kerry-Anne , Toya Naoki , Kanaoka Yuji , Yanaga Katsuhiko , Ohki Takao , Saku Keijiro , Nagai Ryozo
Published: February 2007

Background—

Plasma high-density lipoprotein (HDL) levels have an inverse correlation with incidence of ischemic heart disease as well as other atherosclerosis-related ischemic conditions. However, the molecular mechanism by which HDL prevents ischemic disease is not fully understood. Here, we investigated the effect of HDL on differentiation of endothelial progenitor cells and angiogenesis in murine ischemic hindlimb model.

Methods and Results—

Intravenous injection of reconstituted HDL (rHDL) significantly augmented blood flow recovery and increased capillary density in the ischemic leg. rHDL increased the number of bone marrow–derived cells incorporated into the newly formed capillaries in ischemic muscle. rHDL induced phosphorylation of Akt in human peripheral mononuclear cells. rHDL (50 to 100 μg apolipoprotein A-I/mL) promoted differentiation of peripheral mononuclear cells to endothelial progenitor cells in a dose-dependent manner. The effect of rHDL on endothelial progenitor cells differentiation was abrogated by coadministration of LY294002, an inhibitor of phosphatidylinositol 3-kinase. rHDL failed to promote angiogenesis in endothelial NO–deficient mice.

Conclusions—

rHDL directly stimulates endothelial progenitor cell differentiation via phosphatidylinositol 3-kinase/Akt pathway and enhances ischemia-induced angiogenesis. rHDL may be useful in the treatment of patients with ischemic cardiovascular diseases.
Cholesteryl Ester Transfer Protein (CETP) Expression Protects Against Diet Induced Atherosclerosis in SR-BI Deficient Mice
Authors: Harder Christopher , Lau Paulina , Meng Andrew , Whitman Stewart C. , McPherson Ruth
Published: February 2007

Objective—

To determine whether expression of the human CETP transgene protects against diet-induced atherosclerosis in SR-BI deficient mice.

Methods and Results—

SR-BI deficient (−/−) mice were crossed with CETP transgenic (CETPtg) mice to produce a colony of SR-BI
−/−
× CETPtg mice in a C57Bl/6 background. Age and sex matched groups of genetically modified and wild-type C57Bl/6 mice were fed a high fat, high cholesterol diet for 22 weeks. In both wild-type and SR-BI
−/−
mice, expression of the CETP transgene reduced the cholesterol content and increased the density of lipoprotein particles in the HDL density range. In SR-BI
−/−
× CETPtg mice, CETP activity inversely correlated with total plasma cholesterol levels and shifted the buoyant HDL typical of SR-BI deficiency toward a more normal density HDL particle. Atherosclerosis at the level of the aortic arch was evident in both male and female SR-BI deficient mice but occurred to a greater extent in the females. Expression of CETP markedly attenuated the development of atherosclerosis in SR-BI deficient mice fed an atherogenic diet (
P
<0.003).

Conclusions—

Expression of the human CETP transgene protects SR-BI deficient mice from atherosclerosis, consistent with a role for CETP in remodeling HDL and providing an alternative pathway for the selective uptake of HDL-CE by the liver.
Therapeutic Application of 20-kHz Transcranial Ultrasound in an Embolic Middle Cerebral Artery Occlusion Model in Rats
Authors: Wilhelm-Schwenkmezger Thomas , Pittermann Patrick , Zajonz Katharina , Kempski Oliver , Dieterich Marianne , Nedelmann Max
Published: February 2007

Background and Purpose—

Therapeutic application of diagnostic ultrasound has been shown to improve recanalization rates in patients with acute cerebral vessel occlusion. There is experimental evidence that low-frequency ultrasound may be superior. This study was designed to evaluate the therapeutic efficacy and safety of low-frequency ultrasound in an embolic middle cerebral artery occlusion model in rats. A parameter setting was used that had not previously shown any side effects and interactions with healthy rat brain tissue.

Methods—

Male Wistar rats were submitted to middle cerebral artery clot embolism and transcranial treatment with 20-kHz continuous-wave ultrasound (0.2 W/cm
2
), either alone or in combination with recombinant tissue-type plasminogen activator. Control groups received no treatment or recombinant tissue-type plasminogen activator alone. Outcome assessment consisted of determination of infarct volume and neurological evaluation.

Results—

Eleven animals treated with ultrasound died during the follow-up period of 7 days, compared with 2 animals in the control groups (
P
=0.028). In 3 animals, subarachnoid hemorrhage was detected (1 in the control group). The other animals that died displayed secondary worsening after an initial period of normal vigilance. Histological examination revealed massive edema formation. In surviving animals, no benefit of treatment could be demonstrated.

Conclusions—

In this study, 20-kHz continuous-wave ultrasound caused death in a significant number of animals. Ultrasound at 20 kHz does not seem to be suitable for transcranial therapeutic cerebral application. The data underline the necessity to obtain further animal data to establish the safety limits of frequency and power output.
The Metabolic Syndrome and the Carotid Artery Structure in Noninstitutionalized Elderly Subjects
Authors: Empana Jean-Philippe , Zureik Mahmoud , Gariepy Jerome , Courbon Dominique , Dartigues Jean Francois , Ritchie Karen , Tzourio Christophe , Alperovitch Annick , Ducimetiere Pierre
Published: February 2007

Background and Purpose—

In contrast to the young adult population, limited data are presently available regarding the epidemiology of the metabolic syndrome (MetS) and its relationship with cardiovascular disease risk in the elderly. We have investigated the frequency of the MetS and its association with the carotid artery structure in an elderly free-living population.

Methods—

The study population consists of 5585 French noninstitutionalized elderly men and women aged 65 to 85 years, free of diabetes, who participated in the multicenter Three City Study and who underwent ultrasound examination of the carotid arteries at baseline examination between March 1999 and March 2001. The MetS was defined according to the National Cholesterol Education Program Adult Treatment Panel III criteria.

Results—

The MetS was present in 12.1% of the study participants, with slightly higher rates in men. Subjects with the MetS had higher frequency of carotid plaques (odds ratio, 1.30; 95% CI, 1.09 to 1.55), higher intima-media thickness of the common carotid artery (odds ratio, 1.81; 95% CI, 1.37 to 2.41), and higher lumen diameter (odds ratio, 2.17; 95% CI, 1.61 to 2.94) (upper quintiles) after adjustment for other cardiovascular risk factors. This association was observed in both genders and in subjects without prevalent cardiovascular disease. Elevated blood pressure as defined in the MetS was the main determinant of the relations between the MetS and the carotid parameters, especially the lumen diameter.

Conclusions—

The present data suggest that noninstitutionalized elderly subjects with the MetS have altered structure of the carotid arteries.
The Impact of Recanalization on Ischemic Stroke Outcome
Authors: Rha Joung-Ho , Saver Jeffrey L.
Published: February 2007

Background and Purpose—

For a biomarker to serve as an auxiliary or surrogate outcome measure, it must be tightly correlated with and causally related to functional clinical outcome. Vessel recanalization is a potential surrogate outcome marker for functional outcome in trials of thrombolytic and mechanical recanalization therapies in acute stroke, but the correlation of recanalization and clinical outcome has not been previously systematically reviewed.

Methods—

Through Medline search, we identified and abstracted recanalization and outcome data from all articles published between 1985 and 2002 that assessed vessel recanalization, either spontaneous or therapeutically induced, in acute ischemic stroke.

Results—

Fifty-three studies encompassing 2066 patients reported recanalization rates. Recanalization rates categorized according to intervention were: spontaneous (24.1%), intravenous fibrinolytic (46.2%), intra-arterial fibrinolytic (63.2%), combined intravenous–intra-arterial (67.5%), and mechanical (83.6%). Clinical outcome data categorized by success or failure in achieving recanalization was available from 33 articles encompassing 998 patients. Good functional outcomes at 3 months were more frequent in recanalized versus nonrecanalized patients with odds ratio of 4.43 (95% CI, 3.32 to 5.91). Three-month mortality was reduced in recanalized patients (odds ratio, 0.24; 95% CI, 0.16 to 0.35). Rates of symptomatic hemorrhagic transformation did not differ between the 2 groups (odds ratio, 1.11; 95% CI, 0.71 to 1.74).

Conclusions—

Formal meta-analysis confirms a strong correlation between recanalization and outcome in acute ischemic stroke. Recanalization is strongly associated with improved functional outcomes and reduced mortality. These findings suggest that recanalization is an appropriate biomarker of therapeutic activity in early phase trials of thrombolytic treatment in acute ischemic stroke.
Divine Command and Human Initiative: A Literary View On Numbers 25-31
Authors: Grossman Jonathan
Published: February 2007

Numbers 25-31 is a literary unit that has puzzled many scholars. Between the divine command to go to war against the Midianites and its fulfillment appear stories and laws that interfere with the logical expected narrative. This article suggests dealing with this issue by looking into the 'Deep Structure' of these chapters. Opening this segment is the story of God's command to Moses. The command once fulfilled is to pacify the divine wrath now being inflicted on Israel. Immediately following this divine speech Phine-has slays the sinners Zimri and Cozbi on his own initiative, and thus the divine wrath is quieted. This episode raises the issue of divine command verses human initiative. The chapters following Phinehas' act, chs. 25-31, deal with this matter. They do so through a unique structure comprised of three pairs of stories or laws. These pairs maintain a permanent interaction between divine command and voluntary human initiative relating to that command. The unit expands on this interaction while focusing on three aspects that have surfaced in the story of Phinehas' zeal: the undermining of Moses' authority, women's place in religious rituals, and the bringing of sacrifice to God. Positioning this unit between the command to attack the Midianites and its fulfillment focuses the reader's attention on the tension raised by the story of Phinehas, tension that unravels as the unit advances.