bluuebunny/crossref_metadata_2025 huggingface dataset:
Conditional phase‐type distributions for modelling patient length of stay in hospital
Authors: Marshall A. H. , McClean S. I.
Published: October 2003

The proportion of elderly in the population is continuing to increase, placing additional demands on highly competitive medical budgets. The management of the care of the elderly within hospitals can be assisted by the accurate modelling of the length of stay of patients in hospital. This paper uses conditional phase‐type distributions for modelling the length of stay of a group of elderly patients in hospital. The model incorporates the use of Bayesian belief networks with Coxian phase‐type distributions, a special type of Markov model that describes the duration of stay in hospital as a process consisting of a sequence of latent phases. The incorporation of the Bayesian belief network in the model permits the inclusion of additional patient information which may provide a better understanding of the system, in particular the incorporation of any potential causal information that may exist in the data.
The Effect Of International Acquisitions on Firm Leverage
Authors: Chkir Imed , Cosset Jean‐Claude
Published: October 2003

To determine whether corporate international diversification leads firms to increase their leverage, we perform an event study that compares the leverage of corporations before and after they acquire foreign subsidiaries. We find that on average leverage increases from the first to the third year following the acquisition. When we examine the relation between additional debt financing after foreign acquisitions and the characteristics of these acquisitions, we find that in addition to such major determinants as size and profitability, debt financing is explained by geographical and industrial diversification effects.
A Comparison of Underwriting Costs of Initial Public Offerings by Investment and Commercial Banks
Authors: Fields Paige , Fraser Donald , Bhargava Rahul
Published: October 2003

We examine differences in underwriting costs between commercial‐bank‐Section‐20‐underwritten initial public offerings (IPOs) and investment‐bank‐underwritten IPOs. Our results suggest that total underwriting costs (gross margin plus underpricing) are significantly lower for commercial bank IPOs. The lower cost for commercial bank IPOs is attributable to less severe underpricing for these issues. Gross margin costs generally do not differ between commercial bank and investment bank issues. Furthermore, we find that the long‐run stock price performance for commercial bank issues is superior to that of investment bank issues. That is, lower underpricing for Section 20 issues may not be a short‐run phenomenon. Rather, there appears to be a favorable outcome for investors in the long run for holding IPOs underwritten by Section 20 commercial banks. These results are inconsistent with the conflict of interest hypothesis often associated with merging commercial and investment bank functions in one organization.
BRCT Repeats As Phosphopeptide-Binding Modules Involved in Protein Targeting
Authors: Manke Isaac A. , Lowery Drew M. , Nguyen Anhco , Yaffe Michael B.
Published: October 2003

We used a proteomic approach to identify phosphopeptide-binding modules mediating signal transduction events in the DNA damage response pathway. Using a library of partially degenerate phosphopeptides, we identified tandem BRCT (BRCA1 carboxyl-terminal) domains in PTIP (Pax transactivation domain-interacting protein) and in BRCA1 as phosphoserine- or phosphothreonine-specific binding modules that recognize substrates phosphorylated by the kinases ATM (ataxia telangiectasia–mutated) and ATR(ataxia telangiectasia– and RAD3-related) in response to γ-irradiation. PTIP tandem BRCT domains are responsible for phosphorylation-dependent protein localization into 53BP1- and phospho-H2AX (γ-H2AX)–containing nuclear foci, a marker of DNA damage. These findings provide a molecular basis for BRCT domain function in the DNA damage response and may help to explain why the BRCA1 BRCT domain mutation Met
1775
→ Arg, which fails to bind phosphopeptides, predisposes women to breast and ovarian cancer.
Attrition and Translation
Authors: Duyk Geoffrey
Published: October 2003

The recently published NIH Roadmap proposes that public-sector science should place increased emphasis on the development of new therapeutics and diagnostics based on the fruits of fundamental research. Such “translational research” activities, traditionally the province of the private sector, have long been compromised by high rates of attrition (failure during the course of preclinical or clinical development of therapeutics). Attrition has led to growing financial costs, as well as opportunity costs. The new focus offers a way to reverse these trends, especially if the scientific community can improve on its ability to reconcile molecular genetic research with integrative organ- and organism-based research.
Tenofovir Resistance and Resensitization
Authors: Wolf Katharina , Walter Hauke , Beerenwinkel Niko , Keulen Wilco , Kaiser Rolf , Hoffmann Daniel , Lengauer Thomas , Selbig Joachim , Vandamme Anne-Mieke , Korn Klaus , Schmidt Barbara
Published: October 2003

Human immunodeficiency viruses in 321 samples from tenofovir-naïve patients were retrospectively evaluated for resistance to this nucleotide analogue. All virus strains with insertions between amino acids 67 and 70 of the reverse transcriptase (n= 6) were highly resistant. Virus strains with the Q151M mutation were divided into susceptible (n= 12) and highly resistant (n= 8) viruses. This difference was due to the absence or presence of the K65R mutation, which was confirmed by site-directed mutagenesis. Viral clones with various combinations of the mutations M41L, K70R, L210W, and T215F or T215Y were analyzed for cross-resistance induced by thymidine analogue mutations (TAMs). The levels of increased resistance induced by single, double, and triple mutations at the indicated positions could be ranked as follows: for mutants with single mutations, mutations at positions 41 > 215 > 70; for mutants with double mutations, mutations at positions 41 and 215 > 70 and 215 = 210 and 215 > 41 and 70; for mutants with triple mutations, mutations at positions 41, 210, and 215 > 41, 70, and 215. Viral clones with M184V or M184I exhibited slightly increased susceptibilities to tenofovir (0.7-fold). Almost all clones with TAM-induced resistance were resensitized when M184V was present (P< 0.001). Among the viruses in the clinical samples, the rate of tenofovir resistance significantly increased with the number of TAMs both in the samples with 184M and in those with 184V (P= 0.005 andP= 0.003, respectively). A resensitizing effect of M184V was confirmed for all samples exhibiting at least one TAM (P= 0.03). However, accumulation of at least two TAMs resulted in more than 2.0-fold reduced susceptibility to tenofovir, irrespective of the presence of M184V. Decision tree building, a classical machine learning technique, was used to generate models for the interpretation of mutations with respect to tenofovir resistance. The application of previously proposed cutoffs for a reduced response to therapy and treatment failure demonstrated the central roles of positions 215 and 65 for 1.5- and 4.0-fold reduced susceptibilities, respectively. Thus, clinically relevant resistance may be conferred by the accumulation of TAMs, and the resensitizing effect of M184V should be considered only minor.
In Vitro Activity and Interaction of Clindamycin Combined with Dihydroartemisinin against
Plasmodium falciparum
Authors: Ramharter M. , Noedl H. , Winkler H. , Graninger W. , Wernsdorfer W. H. , Kremsner P. G. , Winkler S.
Published: October 2003

Combination regimens are considered a valuable tool for the fight against drug-resistant falciparum malaria. This study was conducted to evaluate the antimalarial potential of clindamycin in combination with dihydroartemisinin in continuously cultured and in freshly isolated
Plasmodium falciparum
parasites, measuring the inhibition of
Plasmodium falciparum
histidine-rich protein II synthesis. Interaction analysis revealed a synergistic or additive mode of interaction at various concentration ratios in all continuously cultured parasites at the 50% effective concentration (EC
50
) level. Antagonism was not found for any of the culture-adapted parasites. In fresh
P. falciparum
isolates, a fixed clindamycin-dihydroartemisinin combination exhibited additive activity at the EC
50
and EC
90
levels. The drug mixture showed no significant activity correlation to other commonly used antimalarials. The clindamycin-dihydroartemisinin combination appears to be a promising candidate for clinical investigation.
Mutations in Topoisomerase Genes of Fluoroquinolone-Resistant Salmonellae in Hong Kong
Authors: Ling J. M. , Chan E. W. , Lam A. W. , Cheng A. F.
Published: October 2003

A total of 88 salmonella isolates (72 clinical isolates for which the ciprofloxacin MIC was >0.06 μg/ml, 15 isolates for which the ciprofloxacin MIC was ≤0.06 μg/ml, and
Salmonella enterica
serotype Typhimurium ATCC 13311) were studied for the presence of genetic alterations in four quinolone resistance genes,
gyrA
,
gyrB
,
parC
, and
parE
, by multiplex PCR amplimer conformation analysis. The genetic alterations were confirmed by direct nucleotide sequencing. A considerable number of strains had a mutation in
parC
, the first to be reported in salmonellae. Seven of the isolates sensitive to 0.06 μg of ciprofloxacin per ml had a novel mutation at codon 57 of
parC
(Tyr57→Ser) which was also found in 29 isolates for which ciprofloxacin MICs were >0.06 μg/ml. Thirty-two isolates had a single
gyrA
mutation (Ser83→Phe, Ser83→Tyr, Asp87→Asn, Asp87→Tyr, or Asp87→Gly), 34 had both a
gyrA
mutation and a
parC
mutation (29 isolates with a
parC
mutation of Tyr57→Ser and 5 isolates with a
parC
mutation of Ser80→Arg). Six isolates which were isolated recently (from 1998 to 2001) were resistant to 4 μg of ciprofloxacin per ml. Two of these isolates had double
gyrA
mutations (Ser83→Phe and Asp87→Asn) and a
parC
mutation (Ser80→Arg) (MICs, 8 to 32 μg/ml), and four of these isolates had double
gyrA
mutations (Ser83→Phe and Asp87→Gly), one
parC
mutation (Ser80→Arg), and one
parE
mutation (Ser458→Pro) (MICs, 16 to 64 μg/ml). All six of these isolates and those with a Ser80→Arg
parC
mutation were
S. enterica
serotype Typhimurium. One
S. enterica
serotype Typhi isolate harbored a single
gyrA
mutation (Ser83→Phe), and an
S. enterica
serotype Paratyphi A isolate harbored a
gyrA
mutation (Ser83→Tyr) and a
parC
mutation (Tyr57→Ser); both of these isolates had decreased susceptibilities to the fluoroquinolones. The MICs of ciprofloxacin, levofloxacin, and sparfloxacin were in general the lowest of those of the six fluoroquinolones tested. Isolates with a single
gyrA
mutation were less resistant to fluoroquinolones than those with an additional
parC
mutation (Tyr57→Ser or Ser80→Arg), while those with double
gyrA
mutations were more resistant.
Attenuation of Itraconazole Fungicidal Activity following Preexposure of
Aspergillus fumigatus
to Fluconazole
Authors: Liu Wei , Lionakis Michail S. , Lewis Russell E. , Wiederhold Nathan , May Gregory S. , Kontoyiannis Dimitrios P.
Published: October 2003

Fluconazole (FLC), a triazole with limited activity against
Aspergillus
species, is frequently used as prophylaxis in leukemia patients and bone marrow transplant recipients. Prior FLC use has been associated with an increasing incidence of invasive aspergillosis in these patients. We hypothesized that prior exposure of
Aspergillus fumigatus
to FLC could result in altered in vitro susceptibility of this fungus to other, more active triazoles. Thus, we performed serial passages of conidia of 10 clinical isolates of
A. fumigatus
(all itraconazole [ITC] susceptible) on FLC-containing yeast agar glucose plates. The MICs and minimal fungicidal concentrations (MFCs) of amphotericin B, FLC, ITC, and voriconazole (VRC) for
A. fumigatus
conidia were measured following four passages on FLC-containing medium according to the National Committee for Clinical Laboratory Standards microdilution method. Serial passages on FLC-containing plates resulted in a fourfold increase in the MFCs (but not the MICs) of ITC for nine isolates. The attenuated ITC fungicidal activity against
A. fumigatus
following FLC preexposure was medium independent and was also observed against FLC-preexposed
A. fumigatus
hyphae with the viability staining FUN-1 dye. Moreover, FLC preexposure of
A. fumigatus
conidia resulted in an analogous increase in the MFCs (but not the MICs) of VRC. Our findings suggest that preexposure of
A. fumigatus
to FLC attenuates the in vitro fungicidal activity of subsequent ITC use against it. This phenotypic adaptation is not captured by a routine MIC determination but requires MFC measurement. The in vivo significance of this in vitro phenomenon requires further investigation.
Flow Cytometry Antifungal Susceptibility Testing of
Aspergillus fumigatus
and Comparison of Mode of Action of Voriconazole vis-à-vis Amphotericin B and Itraconazole
Authors: Ramani Rama , Gangwar Madhurama , Chaturvedi Vishnu
Published: October 2003

Aspergillus fumigatus
isolates were tested with three antifungals by flow cytometry (FC) and fluorescence-activated cell sorting. FC results after 4 h correlated well with MICs obtained by the NCCLS M38-A method; voriconazole exhibited fungicidal activity, albeit to a lesser extent than amphotericin B, but to a greater extent than itraconazole.
Simulation of Human Gentamicin Pharmacokinetics in an Experimental
Enterococcus faecalis
Endocarditis Model
Authors: Dubé Laurent , Caillon Jocelyne , Gras-Le Guen Christèle , Jacqueline Cédric , Kergueris Marie-France , Granry Jean-Claude , Potel Gilles , Bugnon Denis
Published: October 2003

Significant differences between animal and human pharmacokinetics may be responsible for the conflicting results of experimental studies. This study determined the impact of human pharmacokinetic simulation (HPS) on gentamicin activity in an
Enterococcus faecalis
endocarditis model. The decrease in bacterial counts was greater with HPS than with a dose-equivalent regimen without HPS.
PPE Protein (Rv3873) from DNA Segment RD1 ofMycobacterium tuberculosis: Strong Recognition of Both Specific T-Cell Epitopes and Epitopes Conserved within the PPE Family
Authors: Okkels Limei Meng , Brock Inger , Follmann Frank , Agger Else Marie , Arend Sandra M. , Ottenhoff Tom H. M. , Oftung Fredrik , Rosenkrands Ida , Andersen Peter
Published: October 2003

Proteins encoded by DNA segment RD1 ofMycobacterium tuberculosishave recently been demonstrated to play important roles in bacterial virulence, vaccine development, and diagnostic reagent design. Previously, we characterized two immunodominant T-cell antigens, the early secreted antigen target (ESAT-6) and the 10-kDa culture filtrate protein (CFP10), which are encoded by theesx-lhpoperon in this region. In the present study we characterized a third putative open reading frame in this region,rv3873, which encodes a PPE protein. We found that therv3873gene is expressed inM. tuberculosisH37Rv and that the native protein, Rv3873, is predominantly associated with the mycobacterial cell or wall. When tested as a His-tagged recombinant protein, Rv3873 stimulated high levels of gamma interferon secretion in peripheral blood mononuclear cells isolated from tuberculosis (TB) patients, as well as from healthy tuberculin purified protein derivative-positive donors. In contrast to other RD1-encoded antigens, Rv3873 was also found to be recognized by a significant proportion ofMycobacterium bovisBCG-vaccinated donors. Epitope mapping performed with overlapping peptides revealed a broad pattern of T-cell recognition comprising both TB-specific epitopes and epitopes also recognized by BCG-vaccinated donors. The immunodominant epitope (residues 118 to 135) for both TB patients and BCG-vaccinated individuals was found to be highly conserved among a large number of PPE family members.
Ribonucleotide Reduction in
Mycobacterium tuberculosis
: Function and Expression of Genes Encoding Class Ib and Class II Ribonucleotide Reductases
Authors: Dawes Stephanie S. , Warner Digby F. , Tsenova Liana , Timm Juliano , McKinney John D. , Kaplan Gilla , Rubin Harvey , Mizrahi Valerie
Published: October 2003

Mycobacterium tuberculosis
, the causative agent of tuberculosis, possesses a class Ib ribonucleotide reductase (RNR), encoded by the
nrdE
and
nrdF2
genes, in addition to a putative class II RNR, encoded by
nrdZ
. In this study we probed the relative contributions of these RNRs to the growth and persistence of
M. tuberculosis
. We found that targeted knockout of the
nrdF2
gene could be achieved only in the presence of a complementing allele, confirming that this gene is essential under normal, in vitro growth conditions. This observation also implied that the alternate class Ib small subunit encoded by the
nrdF1
gene is unable to substitute for
nrdF2
and that the class II RNR, NrdZ, cannot substitute for the class Ib enzyme, NrdEF2. Conversely, a Δ
nrdZ
null mutant of
M. tuberculosis
was readily obtained by allelic exchange mutagenesis. Quantification of levels of
nrdE
,
nrdF2
,
nrdF1
, and
nrdZ
gene expression by real-time, quantitative reverse transcription-PCR with molecular beacons by using mRNA from aerobic and O
2
-limited cultures showed that
nrdZ
was significantly induced under microaerophilic conditions, in contrast to the other genes, whose expression was reduced by O
2
restriction. However, survival of the Δ
nrdZ
mutant strain was not impaired under hypoxic conditions in vitro. Moreover, the lungs of B6D2/F
1
mice infected with the Δ
nrdZ
mutant had bacterial loads comparable to those of lungs infected with the parental wild-type strain, which argues against the hypothesis that
nrdZ
plays a significant role in the virulence of
M. tuberculosis
in this mouse model.
Absence of the Macrophage Mannose Receptor in Mice Does Not Increase Susceptibility toPneumocystis cariniiInfection In Vivo
Authors: Swain Steve D. , Lee Sena J. , Nussenzweig Michel C. , Harmsen Allen G.
Published: October 2003

Host defense against the opportunistic pathogenPneumocystis cariniirequires functional interactions of many cell types. Alveolar macrophages are presumed to be a vital host cell in the clearance ofP. carinii, and the mechanisms of this interaction have come under scrutiny. The macrophage mannose receptor is believed to play an important role as a receptor involved in the binding and phagocytosis ofP. carinii. Although there is in vitro evidence for this interaction, the in vivo role of this receptor inP. cariniiclearance in unclear. Using a mouse model in which the mannose receptor has been deleted, we found that the absence of this receptor is not sufficient to allow infection byP. cariniiin otherwise immunocompetent mice. Furthermore, when mice were rendered susceptible toP. cariniiby CD4+depletion, mannose receptor knockout mice (MR-KO) had pathogen loads equal to those of wild-type mice. However, the MR-KO mice exhibited a greater influx of phagocytes into the alveoli during infection. This was accompanied by increased pulmonary pathology in the MR-KO mice, as well as greater accumulation of glycoproteins in the alveoli (glycoproteins, including harmful hydrolytic enzymes, are normally cleared by the mannose receptor). We also found that the surface expression of the mannose receptor is not downregulated duringP. cariniiinfection in wild-type mice. Our findings suggest that while the macrophage mannose receptor may be important in the recognition ofP. carinii, in vivo, this mechanism may be redundant, and the absence of this receptor may be compensated for.
Pathogenic
Acanthamoeba
spp. Secrete a Mannose-Induced Cytolytic Protein That Correlates with the Ability To Cause Disease
Authors: Hurt Michael , Neelam Sudha , Niederkorn Jerry , Alizadeh Hassan
Published: October 2003

The pathogenesis of
Acanthamoeba
keratitis begins when
Acanthamoeba
trophozoites bind specifically to mannosylated glycoproteins upregulated on the surfaces of traumatized corneal epithelial cells. When
Acanthamoeba castellanii
trophozoites are grown in
methyl
-α-
d
-mannopyranoside, they are induced to secrete a novel 133-kDa protein that is cytolytic to corneal epithelial cells. Clinical isolates of
Acanthamoeba
spp., and not the soil isolates, were proficient at producing a mannose-induced protein (MIP-133) and generating disease in Chinese hamsters. The purified protein was efficient at killing corneal epithelial cells, the first mechanistic barrier, by inducing apoptosis in a caspase 3-dependent pathway. Subsequent steps in pathogenesis require the amoebae to penetrate and degrade collagen. Only the clinical isolates tested were efficient at migrating through a collagenous matrix in vitro, presumably by MIP-133 degradation of both human type I and human type IV collagen. A chicken anti-MIP-133 antiserum effectively bound to the protein and blocked collagenolytic activity, migration, and cytopathic effects (CPE) against corneal cells in vitro. Chinese hamsters orally immunized with MIP-133 displayed a >30% reduction in disease. Immunoglobulin A isolated from immunized animals bound MIP-133 and blocked CPE on corneal cells in vitro. Animals induced to generate severe chronic infections displayed significant reductions in disease symptoms upon oral immunization postinfection. These data suggest that MIP-133 production might be necessary to initiate corneal disease and that it may play an important role in the subsequent steps of the pathogenic cascade of
Acanthamoeba
keratitis. Furthermore, as antibodies produced both prior to and after infection reduced clinical symptoms of disease, the protein may represent an important immunotherapeutic target for
Acanthamoeba
keratitis.
Evaluation ofBrucella abortusPhosphoglucomutase (pgm) Mutant as a New Live Rough-Phenotype Vaccine
Authors: Ugalde Juan Esteban , Comerci Diego José , Leguizamón M. Susana , Ugalde Rodolfo Augusto
Published: October 2003

Brucella abortusS19 is the vaccine most frequently used against bovine brucellosis. Although it induces good protection levels, it cannot be administered to pregnant cattle, revaccination is not advised due to interference in the discrimination between infected and vaccinated animals during immune-screening procedures, and the vaccine is virulent for humans. Due to these reasons, there is a continuous search for new bovine vaccine candidates that may confer protection levels comparable to those conferred by S19 but without its disadvantages. A previous study characterized the phenotype associated with the phosphoglucomutase (pgm) gene disruption inBrucella abortusS2308, as well as the possible role for the smooth lipopolysaccharide (LPS) in virulence and intracellular multiplication in HeLa cells (J. E. Ugalde, C. Czibener, M. F. Feldman, and R. A. Ugalde, Infect. Immun.68:5716-5723, 2000). In this report, we analyze the protection, proliferative response, and cytokine production induced in BALB/c mice by a Δpgmdeletion strain. We show that this strain synthesizes O antigen with a size of approximately 45 kDa but is rough. This is due to the fact that the Δpgmstrain is unable to assemble the O side chain in the complete LPS. Vaccination with the Δpgmstrain induced protection levels comparable to those induced by S19 and generated a proliferative splenocyte response and a cytokine profile typical of a Th1 response. On the other hand, we were unable to detect a specific anti-O-antigen antibody response by using the fluorescence polarization assay. In view of these results, the possibility that the Δpgmmutant could be used as a vaccination strain is discussed.
Transfer Region of pO113 from EnterohemorrhagicEscherichia coli: Similarity with R64 and Identification of a Novel Plasmid-Encoded Autotransporter, EpeA
Authors: Leyton Denisse L. , Sloan Joan , Hill Rebecca E. , Doughty Steven , Hartland Elizabeth L.
Published: October 2003

EnterohemorrhagicEscherichia coli(EHEC) is a prominent, food-borne cause of diarrhea, bloody diarrhea, and the hemolytic uremic syndrome in industrialized countries. Most strains of EHEC carry the locus for enterocyte effacement (LEE) pathogenicity island, but a proportion of isolates from patients with severe disease do not carry LEE and very little is known about virulence factors in these organisms. LEE-negative strains of EHEC typically express Shiga toxin 2 and carry a large plasmid that encodes the production of EHEC hemolysin. In this study, we determined the nucleotide sequence of the transfer region of pO113, the large hemolysin plasmid from LEE-negative EHEC O113:H21 (EH41). This 63.9-kb region showed a high degree of similarity with the transfer region of R64, and pO113 was capable of self-transmission at low frequencies. Unlike R64 and the relateddot/icmsystem ofLegionella pneumophila, however, pO113 was unable to mobilize RSF1010. In addition, the pO113 transfer region encoded a novel high-molecular-weight serine protease autotransporter ofEnterobacteriaceae(SPATE) protein, termed EpeA. Like other SPATEs, EpeA exhibited protease activity and mucinase activity, but expression was not associated with a cytopathic effect on epithelial cells. Analysis of a second high-molecular-weight secreted protein revealed that pO113 also encodes EspP, a cytopathic SPATE identified previously in EHEC O157:H7. The nucleotide sequences encoding the predicted β-domains ofespPandepeAwere identical and also shared significant homology with a third SPATE protein, EspI. BothespPandepeAwere detected in several LEE-negative clinical isolates of EHEC and thus may contribute to the pathogenesis of this subset of EHEC.
Relative Immunogenicity of PorA Subtypes in a Multivalent
Neisseria meningitidis
Vaccine Is Not Dependent on Presentation Form
Authors: Luijkx Thomas A. , van Dijken Harry , Hamstra Hendrik-Jan , Kuipers Betsy , van der Ley Peter , van Alphen Loek , van den Dobbelsteen Germie
Published: October 2003

The hexavalent meningococcal vaccine HexaMen, containing six PorAs on two vesicles, was tested in clinical studies. Although fourfold increases in serum bactericidal activity (SBA) titers against all of the PorAs were observed, there were significant differences between PorA-specific SBA titers. SBA titers were mainly directed against one PorA from each vesicle, P1.5-2,10 and P1.5-1,2-2, and were lower against the other PorAs, especially P1.7-2,4 and P1.19,15-1. We investigated whether these differences were due to immunological interference that resulted in competition between the three PorAs on the same vesicle or whether they were caused by a difference in the immunogenicities of the separate PorAs. Therefore, mice were immunized either with HexaMen, with six monovalent outer membrane vesicles (OMVs) representing the same six PorAs simultaneously (HexaMix), or with only one of the monovalent OMVs. The immunoglobulin G and SBA titers after HexaMen immunization in mice resembled the results obtained in clinical studies. Although immunization with HexaMix gave higher titers than immunization with HexaMen for some PorAs, the pattern of high and low titers was the same. Similar differences in immunogenicity between subtypes were seen after monovalent immunization when interference was eliminated as a cause of the differences. Monovalent immunization resulted in higher titers for P1.5-1,2-2 and P1.7,16 than immunization with HexaMen. However, no significant differences were found for the weakly immunogenic PorAs, P1.7-2,4 and P1.19,15-1. Since immunization with the six PorAs in the trivalent presentation form (HexaMen) and in the mixture of monovalent vesicles (HexaMix) resulted in the same pattern of high and low titers, we concluded that the differences between the PorA-specific responses are due to differences in the immunogenicities of the various PorAs and not due to interference that results in competition between different PorAs.
Revaccination of Neonatal Calves withMycobacterium bovisBCG Reduces the Level of Protection against Bovine Tuberculosis Induced by a Single Vaccination
Authors: Buddle B. M. , Wedlock D. N. , Parlane N. A. , Corner L. A. L. , de Lisle G. W. , Skinner M. A.
Published: October 2003

Cattle may provide a suitable model for testing ways of improving tuberculosis vaccine efficacy in human infants. A vaccination and challenge study was undertaken in calves to determine the optimal time to vaccinate neonatal animals withMycobacterium bovisbacillus Calmette-Guérin (BCG) for protection against tuberculosis and to determine whether revaccination with BCG was beneficial. Calves (10 per group) were vaccinated with BCG within 8 h of birth or at 6 weeks of age, when immune responses to antigens of environmental mycobacteria were detectable, or vaccinated at birth and revaccinated at 6 weeks. A control group was not vaccinated. BCG vaccination at birth induced strong antigen-specific gamma interferon (IFN-γ) and interleukin-2 (IL-2) responses and antigen-specific activation in CD4+, CD8+, and WC1+γδ T-cell subsets from blood. The proportions of animals per group with macroscopic tuberculous lesions after challenge were 0/10 for BCG at birth, 1/9 for BCG at 6 weeks, 4/10 for the revaccinated group, and 10/10 for the nonvaccinated group. There was no significant difference in the levels of protection between groups vaccinated at birth or at 6 weeks, while animals vaccinated both at birth and at 6 weeks had significantly less protection than those vaccinated only at birth. The revaccinated calves that subsequently developed tuberculous lesions had significantly stronger IFN-γ and IL-2 responses to bovine purified protein derivative after the BCG booster than those in the same group that did not develop lesions. The results indicated that BCG vaccination at birth induced a high level of immunity and that the sensitization of very young animals to antigens of environmental mycobacteria by 6 weeks of age did not affect the effectiveness of BCG. However, BCG revaccination of these young animals was contraindicated.
CapG
−/−
Mice Have Specific Host Defense Defects That Render Them More Susceptible than CapG
+/+
Mice to
Listeria monocytogenes
Infection but Not to
Salmonella enterica
Serovar Typhimurium Infection
Authors: Parikh Shefal S. , Litherland Sally A. , Clare-Salzler Michael J. , Li Wei , Gulig Paul A. , Southwick Frederick S.
Published: October 2003

Loss of the actin filament capping protein CapG has no apparent effect on the phenotype of mice maintained under sterile conditions; however, bone marrow-derived macrophages from CapG
−/−
mice exhibited distinct motility defects. We examined the ability of CapG
−/−
mice to clear two intracellular bacteria,
Listeria monocytogenes
and
Salmonella enterica
serovar Typhimurium. The 50% lethal dose of
Listeria
was 10-fold lower for CapG
−/−
mice than for CapG
+/+
mice (6 × 10
3
CFU for CapG
−/−
mice and 6 × 10
4
CFU for CapG
+/+
mice), while no difference was observed for
Salmonella
. The numbers of
Listeria
cells in the spleens and livers were significantly higher in CapG
−/−
mice than in CapG
+/+
mice at days 5 to 9, while the bacterial counts were identical on day 5 for
Salmonella-
infected mice. Microscopic analysis revealed qualitatively similar inflammatory responses in the spleens and livers of the two types of mice. Specific immunofluorescence staining analyzed by fluorescence-activated cell sorting revealed similar numbers of macrophages and dendritic cells in infected CapG
−/−
and CapG
+/+
spleens. However, analysis of bone marrow-derived macrophages revealed a 50% reduction in the rate of phagocytosis of
Listeria
in CapG
−/−
cells but a normal rate of phagocytosis of
Salmonella
. Stimulation of bone marrow-derived dendritic cells with granulocyte-macrophage colony-stimulating factor resulted in a reduction in the ruffling response of CapG
−/−
cells compared to the response of CapG
+/+
cells, and CapG
−/−
bone-marrowed derived neutrophils migrated at a mean speed that was nearly 50% lower than the mean speed of CapG
+/+
neutrophils. Our findings suggest that specific motility deficits in macrophages, dendritic cells, and neutrophils render CapG
−/−
mice more susceptible than CapG
+/+
mice to
Listeria
infection.
Alcohol and Hemorrhagic Stroke in Santiago, Chile
Authors: Díaz Violeta , Cumsille Miguel A. , Bevilacqua Jorge A.
Published: October 2003

Background and Purpose: Hemorrhagic stroke (HS) is a major cause of disability and death worldwide. There is a dearth of information on HS from geographically defined populations in Latin America. In this study we assessed the importance of alcohol consumption as a risk factor for HS in Chile. Methods: Case-control study in Santiago, Chile, of 140 consecutive patients with CT-confirmed HS, matched by sex and age with 140 hospital controls. Alcohol consumption was measured in grams (ethanol) per week, using a questionnaire administered to the patients or caregivers or both. We defined four categories of alcohol consumption: nondrinkers (0.0 g/week), light (0.1–115 g/week), moderate (116–402.5 g/week) and heavy drinkers (>402.5 g/week). Other variables measured included diabetes mellitus (DM), cigarette smoking, arterial hypertension, liver disease and chronic use of nonsteroidal anti-inflammatory drugs (NSAID). Statistical analysis was performed with STATA 6.0® software. Results: A total of 280 subjects with a mean age of 65.5 years were studied over a 3-year period, 122 men (43.5%) and 158 women (56.5%). Alcohol intake was 394.1 g/week among cases and 174.5 g/week in controls (p = 0.01). The following odds ratios (OR) with 95% confidence intervals (CI) were found: hypertension 4.89 (2.86–10.3) and chronic use of NSAID 3.44 (2.15–12.9). Using conditional logistic regression analysis high alcohol intake was found to have a statistically significant OR of 4.47 (CI 1.14–17.2). Conclusions: In Chile, a high alcohol intake (>402.5 g/week) increased more than 4 times the risk of HS and remained a significant risk factor for HS after controlling for hypertension, cigarette smoking, liver disease, blood cholesterol levels, and chronic use of NSAID. The risk was higher in younger patients (<65 years of age).
Anterior Pituitary Cells Express Pattern Recognition Receptors for Fungal Glucans: Implications for Neuroendocrine Immune Involvement in Response to Fungal Infections
Authors: Breuel Kevin F. , Kougias Panagiotis , Rice Peter J. , Wei Duo , De Ponti Keith , Wang Jiakun , Laffan John J. , Li Chuanfu , Kalbfleisch John , Williams David L.
Published: October 2003

Objectives: Hormones and cytokines are known to act as regulatory messengers between the neuroendocrine and immune systems. The innate immune system identifies infectious agents by means of pattern-recognition receptors. These receptors recognize pathogen-specific macromolecules called pathogen-associated molecular patterns. Fungal cell wall glucans nonspecifically stimulate various aspects of innate immunity via interaction with membrane receptors on immune-competent cells. Glucans are also released into the systemic circulation of patients with fungal infections. Recent evidence confirms the existence of glucan-specific receptors on cells outside the immune system. We hypothesized that glucans may directly interact with pituitary cells as an early signaling event in fungal infections. Methods: We characterized the receptor-mediated interaction of glucan derived from Candida albicans with pituitary cells using surface plasmon resonance. Prolactin levels were assayed by commercial ELISA. TLR2, TLR4 and CD14 mRNA levels were assessed by RT-PCR. Results: A single glucan-specific binding site was identified on rodent somatomammotroph (KD = 3.9 µM) and human folliculostellate cell (KD = 3.6 µM) membranes. Coincubation of glucan with somatomammotroph cells for 72 h significantly (p < 0.01) increased prolactin accumulation by 56–62% over that observed in cells treated with media alone. Glucan also increased TLR4 and CD14 gene expression in human folliculostellate cells. Conclusions: Pituitary cells directly recognize and respond to fungal cell wall glucans resulting in stimulation of pituitary cell TLR4 and CD14 gene expression. In addition, glucan stimulates secretion of prolactin, a hormone that plays an important role in the response to infection.
Regulation of Allergic Lung Inflammation in Rats: Interaction between Estradiol and Corticosterone
Authors: Ligeiro de Oliveira Ana Paula , Oliveira-Filho Ricardo M. , da Silva Zilma Lúcia , Borelli Primavera , Tavares de Lima Wothan
Published: October 2003

Objective: One third of asthmatic women report a decreased expiratory peak flow during menses. Since asthma is characterized by lung inflammation and bronchopulmonary hyperresponsiveness, we investigated the role played by estradiol in allergic lung inflammation. Methods: Cell migration to the lungs of allergic female rats subjected to oophorectomy (OVx) was compared to that in their sham-operated (sham) control counterparts. Seven days after OVx or sham operation, the rats were sensitized intraperitoneally with ovalbumin (OA, 1 mg/kg) suspended in aluminum hydroxide (day 0). At day 7, a subcutaneous booster of OA was performed and an aerosolized OA challenge was carried out at day 14. One day later (day 15), the rats were killed and cell counts were performed in bronchoalveolar lavages (BAL), in peripheral blood and in bone marrow lavages. Results: After the antigen challenge, OVx rats showed a significant decrease in cell migration to the lung as compared to sham-operated rats. Differential analyses of BAL revealed a reduced number of eosinophils, mononuclear cells and neutrophils. In contrast, in bone marrow as well as in the peripheral blood the numbers of eosinophils, mononuclear cells and neutrophils were increased relative to sham controls. Mast cell numbers were similar in both groups. The estradiol receptor antagonist tamoxifen decreased the allergic lung inflammation in intact rats down to levels similar to those found in untreated OVx rats. In contrast, 17β-estradiol replacement in OVx rats reestablished the allergic lung inflammation, as observed by an elevated number of eosinophils, mononuclear cells and neutrophils recovered in BAL. Similarly, an elevated number of inflammatory cells were quantified in BAL from allergic OVx rats when corticosterone effects were blocked with metyrapone or RU-486. Conclusion: Our results suggest that estradiol has proinflammatory actions on the allergic lung response, and these actions seem to be mediated, at least in part, by endogenous glucocorticoids.
Inhibition of Decrease in Natural Killer Cell Activity in Repeatedly Restraint-Stressed Mice by a Biological Response Modifier Derived from Cultured Mycelia of the Basidiomycete Tricholoma matsutake
Authors: Ishihara Yoko , Iijima Hiroko , Yagi Yoko , Hoshi Hirotaka , Matsunaga Kenichi
Published: October 2003

Objective: To develop a method to cope with stress-induced reduction in immunocompetence, we evaluated the immunomodulatory activities of a biological response modifier derived from the mycelia of the basidiomycete Tricholoma matsutake (CM6271) in mice under repeated restraint stress. Methods: C57BL/6 mice were inserted, one per tube, into 50-ml polypropylene tubes into which more than 30 ventilation holes had been drilled, and were restrained everyday for 20 days in this fashion for set periods of time. Natural killer (NK) cell activity and NK1.1-positive cell counts in the spleen, ACTH and corticosterone levels in the blood were determined. CM6271 was orally administered daily during the restraint stress period. Results: (1) When the mice were restrained in a confined space for 6 h per day for 20 days, the NK cell activity and the NK1.1-positive cell counts in the spleen significantly decreased after day 5 with an increase in the blood ACTH and corticosterone levels. (2) Oral administration of CM6271 during the restraint stress period significantly prevented the stress-induced decrease in NK cell activity. The effect was dependent on the timing, duration, and doses administered. (3) CM6271 did not significantly affect the splenic NK1.1-positive cell counts or the levels of blood ACTH and corticosterone in restraint-stressed mice. Conclusion: The above findings suggest that CM6271 inhibits the restraint stress-induced decrease of NK cell activity in a timing of administration and dose-dependent manner.
Between Acculturation and Ambivalence: Knowledge of Genetics and Attitudes towards Genetic Testing in a Consanguineous Bedouin Community
Authors: Raz Aviad E. , Atar Marcela , Rodnay Maya , Shoham-Vardi Ilana , Carmi Rivka
Published: October 2003

The Bedouins of the Negev (Southern part of Israel) are a community at increased risk for genetic diseases and congenital anomalies as a result of frequent consanguinity (particularly patrilateral parallel-cousin marriage) and underutilization of prenatal genetic tests due to a Muslim ban on abortion. Objective: To assess the knowledge and attitudes of Bedouin schoolchildren and their teachers towards a community-based, premarital carrier-matching program aimed at reducing the prevalence at birth of genetic diseases. Methods: A questionnaire was presented to 61 teachers and 40 schoolchildren as part of guided interaction in small groups, conducted in Bedouin schools between 1999 and 2001. Results: Susceptibility as well as knowledge of genetics were found to correlate with a positive attitude towards the genetics program among both teachers and pupils. However, pupils had a lower knowledge index as compared to teachers, and their attitudes were slightly less positive. Conclusion: The difference between teachers and pupils is discussed in the context of the latter’s acculturation, which contradicts tradition and parental authority and can generate ambivalence. Attitudes are further discussed in the context of the Health Belief Model and the complex interplay of tradition, Islam, cousin marriage and biomedicine.
Dobutamine Stress Echocardiography in Hypertrophic Cardiomyopathy
Authors: Losi Maria Angela , Betocchi Sandro , Aversa Mariano , Lombardi Raffaella , Miranda Marianna , Cacace Alessandra , Ciampi Quirino , Tocchetti Carlo Gabriele , Guida Adriana , Chiariello Massimo
Published: October 2003

Aims: Myocardial ischemia in the absence of coronary artery disease is common in patients with hypertrophic cardiomyopathy (HCM). Dobutamine stress echocardiography (DSE) induces left ventricular (LV) new wall motion abnormalities (NWMA) in some patients with HCM. We evaluated the effects of dobutamine on LV performance and hemodynamics in HCM. Methods and Results: Eighteen patients with non-obstructive HCM underwent DSE. Dobutamine was administered at dosages of 5, 10, 20, 30 and 40 µg/kg/min with increments at intervals of 3 min. Seven patients developed NWMA, whereas the other 11 did not. During DSE, heart rate increased significantly more in NWMA patients,whereas LV outflow tract gradient (OTG) increased significantly and similarly in both groups. At peak dobutamine dose, NWMA patients had a significant increase in LV end-systolic diameter and volume and a significant decrease in LV fractional shortening and ejection fraction. Posterior wall thickening increased significantly, whereas septal thickening did not increase throughout DSE in both groups. Conclusions: In a subgroup of patients with HCM, DSE induces NWMA, associated with a greater increase in heart rate, irrespective of LVOTG. NWMA induce a depression of global LV systolic performance. The septum shows no contractile reserve, regardless of NWMA. These phenomena may be the result of induction of ischemia and/or impaired LV systolic function due to fast heart rate.
Incidence of Cystoid Macular Edema after Uncomplicated Phacoemulsification
Authors: Mentes Jale , Erakgun Tansu , Afrashi Filiz , Kerci Gokhan
Published: October 2003

We determined the incidence and causes of clinical and angiographic cystoid macular edema (CME) after uncomplicated phacoemulsification and intraocular lens implantation in otherwise normal eyes. This study comprised 252 eyes of 252 patients who had uncomplicated phacoemulsification with continuous curvilinear capsulorhexis and in-the-bag acrylic intraocular lens implantation. The presence of clinical and angiographic CME was evaluated 45 days after surgery, using fundus fluorescein angiography. Age, sex, cataract type, iris color, and real phacoemulsification time of the patients were also recorded. The mean age of the patients was 69.86 (range 60–82) years). Clinical CME was not detected in any eye at any postoperative visit. There were 23 cases with angiographic CME (9.1%). There were no significant differences between the groups who were later found to be angiographically CME-positive or CME-negative in any variable recorded (p >0.05). The incidences of clinical and angiographic CME after uncomplicated phacoemulsification were 0 and 9.1%, respectively. These results indicate that the occurrence of clinical CME has greatly reduced after uncomplicated phacoemulsification operations, but the incidence of angiographic CME is still nearly equal to the incidence of the extracapsular technique.
Improvement of Mild Inflammatory Changes of the Facial Skin Induced by Winter Environment with Daily Applications of a Moisturizing Cream
Authors: Kikuchi Katsuko , Kobayashi Hiromi , Hirao Tetsuji , Ito Akira , Takahashi Haruhito , Tagami Hachiro
Published: October 2003

Objective: Based on our previous findings that, reflecting mild inflammation, the exposed facial skin shows much poorer functional properties of the stratum corneum (SC) in the dry and cold winter than those evaluated in the same individuals in the warm and humid summer time, we conducted a half-side test on the face to determine how the facial skin changes induced by a winter environment are improved by daily applications of a moisturizing cream as assessed by non-invasive biophysical and cytological methods. Methods: One side of the face of 16 young females was treated with a moisturizing cream twice daily for 6 weeks, with the other side serving as the non-treated control. Before treatment, 3 and 6 weeks after the start of the treatment, high-frequency conductance as a parameter of the skin surface hydration, transepidermal water loss (TEWL), a parameter of the water barrier function of the skin, and the skin surface lipid level were measured on the cheeks. Obtaining the SC from the skin surface by adhesive tape, interleukin (IL) 1α and IL-1 receptor antagonist (IL-1ra) in the SC and cornified envelope (CE) maturation were determined. Results: At first, baseline measurements conducted before treatment showed rather high TEWL values suggestive of an impaired skin barrier. During the treatment with the moisturizing cream, significantly higher conductance values and lower TEWL values were found on the moisturizer-treated side, accompanied by a decreasing IL-1ra/IL-1α ratio and immature CEs. Conclusion: These results suggested that the daily application of a moisturizing cream is effective in improving mild subclinical inflammation that is induced on the facial skin by the winter environment.