bluuebunny/crossref_metadata_2025 huggingface dataset:
Socioeconomic status and prevalence of allergic rhinitis and atopic eczema symptoms in young adolescents
Authors: Mercer M. J. , Joubert G. , Ehrlich R. I. , Nelson H. , Poyser M. A. , Puterman A. , Weinberg E. G.
Published: June 2004

Environmental factors are known to influence the development of allergic rhinitis and atopic eczema in genetically susceptible individuals. Socioeconomic status (SES) may be an important indicator of risk for these conditions. The International Study of Asthma and Allergies in Childhood (ISAAC) Phase 1 written questionnaire was used to determine the prevalence and severity of allergic rhinoconjunctivitis and atopic eczema symptoms in 4947 pupils aged 13–14 years attending 30 schools in socioeconomically diverse areas of Cape Town. Home addresses were used to stratify participants into five SES bands. Relationships between symptom prevalence and severity, and SES, recent urbanization and upward socioeconomic mobility were examined. Logistic regression was used to generate odds ratios (OR) and 95% confidence intervals (CI) in order to assess overall trends by SES. The prevalences of self‐reported allergic rhinitis symptoms and recurrent itchy rash in the past year were 33.2% and 11.9% respectively. Girls had a significantly higher prevalence of all symptoms than boys. The prevalence of allergic rhinitis symptoms increased from lowest to highest SES (overall OR for rhinitis symptoms in past year = 1.16, 95% CI 1.11–1.21). There was no significant trend in reported eczema symptoms by SES other than for the question, ‘Have you ever had eczema’ (OR = 0.88, 95% CI 0.83–0.93). Longer period of urbanization was weakly associated only with recurrent itchy skin rash (OR = 1.05, 95% CI 1.01–1.09). ‘Socially mobile’ pupils, i.e. those resident in the lowest SES areas but attending highest SES schools showed significantly higher prevalences of eczema and some rhinitis symptoms than pupils attending lowest SES schools. These findings may reflect differences in reporting related to language, culture and access to medical care rather than real differences in prevalence.
Peripheral blood eosinophils and IL‐4 in infancy in relation to the appearance of allergic disease during the first 6 years of life
Authors: Borres M. P. , Björkstén B.
Published: June 2004

Eosinophils in peripheral blood and serum levels of interleukin (IL)‐4 were analysed at 3 and 18 months and at 6 years in a prospective study comprising 67 children, of whom the majority had atopic heredity. The children were monitored from birth up to 6 years of age and the findings were related to family history of allergy and development of allergic disease. Twenty‐nine children (43%) of the original group of 67 children were diagnosed as allergic at the age of six. Fifteen of 23 children with eosinophilia (>4 × 108 eosinophils/l) at 3 months of age were regarded as allergic at 6 years, when compared with 12 out of 38 children with normal eosinophil counts at 3 months (χ2 = 6.7, p < 0.01). Children with detectable IL‐4 in serum at 18 months were more often allergic at 6 years, when compared with those children with no detectable IL‐4 (χ2 = 8.6, p < 0.01). Furthermore, the allergic children had a mean IL‐4 value of 0.35 μg/l (95% CI: 0.10–1.48) at 18 months, when compared with 0.17 μg/l (95% CI: 0.10–0.72, p < 0.001) in the non‐allergic children. At 6 years of age, only nine children had detectable levels of IL‐4 and five of them were classified as allergic. Eosinophilia at this age was also associated with allergic disease. We conclude that eosinophilia during infancy and increased levels of IL‐4 at 18 month of age are associated with allergic disease during the first 6 years of life. This might indicate that the first 2 years of life are particularly important for the development of allergy.
Chorioamnionitis/funisitis and the development of bronchopulmonary dysplasia
Authors: Kent A , Dahlstrom JE
Published: June 2004

Objective:  To examine the association between chorioamnionitis with or without funisitis and bronchopulmonary dysplasia in infants less than 30 completed weeks gestation given the current standards of antenatal steroid and surfactant use.

Methods:  Infants included in the study were those delivered at less than 30 completed weeks gestation from January 1996 to July 2001, identified from a prospectively managed database. Placental pathology was reviewed for the presence or absence of chorioamnionitis and funisitis. Infants were divided into three groups depending on degree of exposure to fetal inflammation (no inflammation, chorioamnionitis only and chorioamnionitis and funisitis). Data relating to gestational age, sex, antenatal steroid exposure, surfactant treatment, days of positive pressure ventilation and days of oxygen required were collected. Bronchopulmonary dysplasia was defined as death due to respiratory failure or any oxygen requirement at 36 weeks postmenstrual age.

Results:  Two hundred and forty‐one infants were included in the study. The mean gestational age was 27.7 weeks and mean birthweight 1089 g. One hundred and sixty‐one infants were not exposed to any in utero inflammation, 40 showed chorioamnionitis and 40 showed chorioamnionitis and funisitis. There was no significant difference between antenatal steroid and surfactant treatment between the three groups. There was no significant difference between the three groups in the development of bronchopulmonary dysplasia. Low gestational age was the most significant predictor of developing bronchopulmonary dysplasia.

Conclusion:  The risk of developing bronchopulmonary dysplasia is not increased following exposure to chorioamnionitis or funisitis in the context of current antenatal steroid and surfactant use. The most significant predictor for developing bronchopulmonary dysplasia is gestational age at the time of delivery.
Prospective cohort study of definite spider bites in Australian children
Authors: Isbister GK
Published: June 2004

Objectives:  To describe the clinical effects of spider bites in a paediatric population and compare to bites in an adult population.

Methods:  Prospective follow up study of children with definite spider bites where the spiders were immediately collected and expertly identified. Cases were recruited from Australian emergency departments and poison information centres and followed up. Data were collected on circumstances of bites and clinical effects, and compared with similar data from adult spider bites.

Results:  There were 163 cases (62% male, 38% female; age <16, median age 7 years, interquartile range (IQR): 3−11 years). The median duration of effects was 2 h (IQR 0.25−12 h). The commonest spiders were Huntsman spiders (Sparassidae) and Orb weavers (Araneidae), and comparatively few bites by theridiid spiders, including Red‐back spiders. Pain or discomfort occurred in all bites and was severe in 20%. Local effects included puncture marks/bleeding (36%) and red mark/redness (73%). Systemic effects occurred in only 6% of cases. There were no necrotic lesions or ulcers as a consequence of any spider bites (0%; 97.5% CI 0.0−2.2%) and no early allergic reactions or secondary infections. The median duration of clinical effects was shorter than adults, the frequency of severe pain was less than adults and systemic effects were less common in children.

Conclusions:  Paediatric spider bite causes minor effects in the majority of cases, and is unlikely to cause necrotic ulcers, allergic reactions or infection. The severity and duration of effects differ from adults.
Arterial ischaemic stroke in children
Authors: Barnes C , Newall F , Furmedge J , Mackay M , Monagle P
Published: June 2004

Objective:  Arterial ischaemic stroke (AIS) in childhood is a serious disorder about which little is published. The aim of this study is to determine the epidemiology and outcome of AIS in Australian children.

Methods:  Cases of childhood AIS occurring at the Royal Children's Hospital, Melbourne 1993−2001, were identified by medical record search using International Classification of Disease Codes. Information was collected on demographics, risk factors, arterial distribution, results of thrombophilic testing, management and outcome.

Results:  During the 8 years of review 95 patients presented with 98 cases of AIS calculating an incidence of 1.8 per 100 000 children per year. Children less than 12 months of age represented greater than one third of all cases. Identifiable risk factors were present in 64% of cases with congenital heart disease the major risk factor. Thrombophilic testing was incomplete with initial abnormalities present in 18% of cases tested. The estimated stroke‐related mortality was 8.4%. Of the patients who survived and who had follow‐up details available, 78% had a neurological deficit. Twenty‐six patients (26%) received anticoagulation. There was no statistically significant association between treatment with anticoagulation and normal neurological outcome.

Conclusion:  AIS is over‐represented in children under 12 months of age and results in death or residual neurological impairment in the majority of cases. Further prospective studies are needed to identify risk factors for poor outcome. The recently established Australian and New Zealand Stroke and Thrombophilia Registry should provide important information on clinical and laboratory based risk factors and create a basis for international clinical trials to improve the outcome of childhood AIS.
Captopril‐induced pancytopenia in a premature newborn
Authors: Tarcan A , Gürakan B , Özbek N
Published: June 2004

Abstract:  A preterm infant with renovascular hypertension who developed significant trilineage bone marrow suppression after receiving captopril is reported. Captopril‐associated pancytopenia is a very rare complication that was thought to be dose‐related and usually caused by accumulation of the drug through defective renal tubular excretion. In our patient, it appears that the combination of renal artery stenosis and renal tubular dysfunction of prematurity might have led to pancytopenia. Captopril should be used with caution especially in premature babies and newborns with underlying renal or renovascular disease even if they do not have overt renal dysfunction. Monitorization of these babies with creatinine clearance or free serum captopril levels may help to establish accumulation of the drug before causing pancytopenia.
Trisomy 21 and Rett syndrome: A double burden
Authors: Leonard H , Weaving L , Eastaugh P , Smith L , Delatycki M , Witt Engerström I , Christodoulou J
Published: June 2004

Abstract: Rett syndrome is a severe neurodevelopmental disorder generally affecting girls. Affected individuals are apparently normal at birth but later pass through a period of regression with loss of hand and communication skills and the development of hand stereotypies and dyspraxia. Mutations in the methyl‐CpG binding protein 2 (MECP2) gene,have now been found to cause Rett syndrome in up to 80% of classical cases. We report a girl with Down syndrome, one of three children with birth defects in a family of five. From the age of 18 months she developed symptomatology considered by her primary physician to be very characteristic of Rett syndrome. However, this remained a clinical diagnosis till the age of 12 years. Laboratory confirmation of the dual diagnosis, which includes a R168X mutation in theMECP2gene in addition to trisomy 21, has now been possible. The presence of one neurological or developmental disorder does not necessarily preclude a diagnosis of Rett syndrome.
Restorative proctocolectomy in patients with ulcerative colitis having a recto‐vaginal fistula
Authors: Zinicola R. , Nicholls R. J.
Published: June 2004

Objective  Recto‐vaginal fistula is a rare complication of ulcerative colitis. There are few reports of restorative proctocolectomy carried out in patients with ulcerative colitis having a rectovaginal fistula. We report our experience with this condition.

Patients and methods  Between 1 January 1976 and 31 December 2001, 838 patients underwent restorative proctocolectomy for ulcerative colitis at one hospital. These included 400 women of whom 4 (1%) had an already present rectovaginal fistula. We reviewed all patients who presented with a rectovaginal fistula. These patients were contacted by telephone to establish function and satisfaction.

Results  The mean age was 30.0 years (range 19–39 years). The mean age at onset of ulcerative colitis was 21.5 years (range 13–34 years). One patient was asymptomatic, the fistula being discovered at operation. In the other three patients the recto‐vaginal fistula had occurred at a mean of 108 months (range 72–192 months) after the onset of ulcerative colitis. Three of four patients had had previous episodes of acute severe disease. Three patients had a narrow rectum with deep ulceration. The mean distance between the anorectal junction and the site of fistulation was 2.7 cm (range 0–7 cm). Three patients had a three‐stage and one patient a two‐stage procedure. Mean follow‐up after closure of the loop ileostomy was 107 months (range17–276 months). All patients were treated successfully but 2 (50%) had a recurrence at 156 and 40 months after the closure of the loop ileostomy. One patient was diverted and the fistula was closed by a subsequent transanal repair and the other patient was treated with success by temporary loose seton technique. Two patients had excellent functional results whereas two other had some difficulties in continence. Nevertheless all patients were satisfied with the outcome.

Conclusions  Patients with ulcerative colitis and a recto‐vaginal fistula can be successfully treated by restorative proctocolectomy, nevertheless they are at risk of late recurrence of the fistula.
Completion rate to caecum as a quality measure of colonoscopy in a district general hospital
Authors: Gorard D. A. , McIntyre A. S.
Published: June 2004

Objective  Published colonoscopy completion rates vary substantially and audits suggest they often fall short of the 85% completion rate to caecum considered acceptable by some authorities. We audited colonoscopy completion rates in our unit and aimed to investigate reasons for failure.

Methods  We analysed all colonoscopies, including those by trainees, performed in a district general hospital over a 16‐month period. Reasons for failure to complete were investigated and alterations to working practices made where necessary.

Results  The unit had an 89.1% completion rate overall (95% CI 87–92%) with rates varying from 75% to 97% for individuals. Colorectal carcinomas were detected in 3.9% of all colonoscopies of which 17% occurred proximal to the caecum and 16% in the ascending colon. Working practices in those endoscopists felt not to be meeting targets were altered and a re‐audit confirmed a trend towards improvement in those individuals. Using these data we also identified a definite learning curve in trainees, with at least 40 procedures required to meet the target of 85% completion rate to caecum.

Conclusion  In a District General Hospital high standards of colonoscopy can be achieved. Reasons for failure to complete colonoscopy to the caecum are many and often they are beyond the control of the colonoscopist (e.g. poor preparation, obstructing lesion). Colonoscopy to the caecum is not always necessary and is not a good measure of the quantity of colonic mucosa visualized. We have reservations with regard to using this target alone as a measure of quality.
When to Stress Over Triptans: A Markov Analysis of Cardiovascular Risk in Migraine Treatment
Authors: Orlando Lori A. , Matchar David B.
Published: June 2004

Background.—Migraines affect 10% of the U.S. population and the episodes are frequently associated with significant disability. Triptans, 5HT1 receptor agonists, can be highly effective in treating pain and reducing disability. However, reports of cardiac events associated with triptan ingestion have led to concerns about its use in the face of possible cardiac disease.

Objective.—Should a patient without known cardiovascular disease (CAD) and moderately severe to severe migraines undergo cardiovascular testing prior to the initiation of triptan therapy?

Design.—A Markov model of migraine and cardiac disease using DATA 4.0. Three strategies were compared: (1) use triptans without further evaluation (TREAT); (2) test, then treat if negative (TEST); and (3) avoid triptans (NOTRIPTAN). Triptans were prohibited if a cardiac event occurred.

Data.—Model inputs were derived from the literature and subjected to sensitivity analyses across all possible values.

Time Horizon.—Markov cycle is 1 week.

Outcomes.—The primary outcomes of interest were quality‐adjusted life expectancy, in years (QALYs) and the impact of various cardiovascular risk levels on the preferred strategy.

Results.—For the base case results were TREAT 19.4 QALYs, TEST 19.2, NOTRIPTAN 19.1. When altering CAD probability: TREAT dominated from 0 to 87%, TEST 87% to 97%, and NOTRIPTAN above 97%. Results were robust during sensitivity analyses.

Conclusions.—This analysis suggests that even for individuals with a relatively high risk of CAD it is not beneficial to perform cardiac testing, nor to avoid triptans. The exact level of cardiac risk at which testing should be considered is probably at or above 87%.
Activation of the Phosphatidylinositol 3-Kinase/Akt Pathway Contributes to Survival of Primary Epithelial Cells Infected with the Periodontal Pathogen
Porphyromonas gingivalis
Authors: Yilmaz Özlem , Jungas Thomas , Verbeke Philippe , Ojcius David M.
Published: June 2004

Porphyromonas gingivalis
, an important periodontal pathogen, infects primary gingival epithelial cells (GECs). Despite the large number of bacteria that replicate inside the GECs, the host cell remains viable. We demonstrate that
P. gingivalis
triggers rapid and reversible surface phosphatidylserine exposure through a mechanism requiring caspase activation. However, after 1 day of infection, the bacteria no longer induce phosphatidylserine externalization and instead protect infected cells against apoptosis. Infection exerts its effect at the level of mitochondria, as
P. gingivalis
also blocks depolarization of the mitochondrial transmembrane potential and cytochrome
c
release. Interestingly, protein kinase B/Akt is phosphorylated during infection, which can be blocked with the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002. Suppression of the PI3K/Akt pathway following staurosporine treatment results in mitochondrial-membrane depolarization, cytochrome
c
release, DNA fragmentation, and increased apoptosis of infected GECs. Thus,
P. gingivalis
stimulates early surface exposure of phosphatidylserine, which could downmodulate the inflammatory response, while also promoting host cell survival through the PI3K/Akt pathway.
Adaptation of
Campylobacter jejuni
NCTC11168 to High-Level Colonization of the Avian Gastrointestinal Tract
Authors: Jones Michael A. , Marston Kerrie L. , Woodall Claire A. , Maskell Duncan J. , Linton Dennis , Karlyshev Andrey V. , Dorrell Nick , Wren Brendan W. , Barrow Paul A.
Published: June 2004

The genome sequence of the human pathogen
Campylobacter jejuni
NCTC11168 has been determined recently, but studies on colonization and persistence in chickens have been limited due to reports that this strain is a poor colonizer. Experimental colonization and persistence studies were carried out with
C. jejuni
NCTC11168 by using 2-week-old Light Sussex chickens possessing an acquired natural gut flora. After inoculation, NCTC11168 initially colonized the intestine poorly. However, after 5 weeks we observed adaptation to high-level colonization, which was maintained after in vitro passage. The adapted strain exhibited greatly increased motility. A second strain,
C. jejuni
11168H, which had been selected under in vitro conditions for increased motility (A. V. Karlyshev, D. Linton, N. A. Gregson, and B. W. Wren, Microbiology
148:
473-480, 2002), also showed high-level intestinal colonization. The levels of colonization were equivalent to those of six other strains, assessed under the same conditions. There were four mutations in
C. jejuni
11168H that reduced colonization;
maf5
,
flaA
(motility and flagellation), and
kpsM
(capsule deficiency) eliminated colonization, whereas
pglH
(general glycosylation system deficient) reduced but did not eliminate colonization. This study showed that there was colonization of the avian intestinal tract by a
Campylobacter
strain having a known genome sequence, and it provides a model for colonization and persistence studies with specific mutations.
RsbU-Dependent Regulation of
Staphylococcus epidermidis
Biofilm Formation Is Mediated via the Alternative Sigma Factor σ
B
by Repression of the Negative Regulator Gene
icaR
Authors: Knobloch Johannes K.-M. , Jäger Sebastian , Horstkotte Matthias A. , Rohde Holger , Mack Dietrich
Published: June 2004

Transposon mutagenesis of
rsbU
leads to a biofilm-negative phenotype in
Staphylococcus epidermidis
. However, the pathway of this regulatory mechanism was unknown. To investigate the role of RsbU in the regulation of the alternative sigma factor σ
B
and biofilm formation, we generated different mutants of the σ
B
operon in
S. epidermidis
strains 1457 and 8400. The genes
rsbU
,
rsbV
,
rsbW
, and
sigB
, as well as the regulatory cascade
rsbUVW
and the entire σ
B
operon, were deleted. Transcriptional analysis of
sarA
and the σ
B
-dependent gene
asp23
revealed the functions of RsbU and RsbV as positive regulators and of RsbW as a negative regulator of σ
B
activity, indicating regulation of σ
B
activity similar to that characterized for
Bacillus subtilis
and
Staphylococcus aureus
. Phenotypic characterization of the mutants revealed that the dramatic decrease of biofilm formation in
rsbU
mutants is mediated via σ
B
, indicating a crucial role for σ
B
in
S. epidermidis
pathogenesis. However, biofilm formation in mutants defective in σ
B
or its function could be restored in the presence of subinhibitory ethanol concentrations. Transcriptional analysis revealed that
icaR
is up-regulated in mutants lacking σ
B
function but that
icaA
transcription is down-regulated in these mutants, indicating a σ
B
-dependent regulatory intermediate negatively regulating IcaR. Supplementation of growth media with ethanol decreased
icaR
transcription, leading to increased
icaA
transcription and a biofilm-positive phenotype, indicating that the ethanol-dependent induction of biofilm formation is mediated by IcaR. This
icaR
-dependent regulation under ethanol induction is mediated in a σ
B
-independent manner, suggesting at least one additional regulatory intermediate in the biofilm formation of
S. epidermidis
.
Overexpression of Interleukin-15 Increases Susceptibility to Lipopolysaccharide-Induced Liver Injury in Mice Primed withMycobacterium bovisBacillus Calmette-Guérin
Authors: Yajima Toshiki , Nishimura Hitoshi , Saito Kimika , Kuwano Hiroyuki , Yoshikai Yasunobu
Published: June 2004

Mice primed withMycobacterium bovisbacillus Calmette-Guérin (BCG) are highly sensitive to lipopolysaccharide (LPS)-induced liver injury and lethality. We found that interleukin-15 (IL-15) transgenic (Tg) mice primed with BCG were more susceptible to LPS-induced liver injury than non-Tg mice. The numbers of CD44+CD8+T cells expressing intracellular gamma interferon (IFN-γ) significantly increased in the livers of BCG-primed IL-15 Tg mice after LPS injection, and the depletion of CD8+T cells from BCG-primed IL-15 Tg mice completely abolished the susceptibility to LPS-induced lethality. Liver T cells from BCG-primed IL-15 Tg mice produced IFN-γ in vitro in response to LPS, which was inhibited by the addition of anti-IL-12 monoclonal antibody (MAb). In vivo treatment with anti-IL-12 MAb inhibited the appearance of CD44+CD8+T cells expressing intracellular IFN-γ after LPS injection. These results suggest that the overexpression of IL-15 increases susceptibility to LPS-induced liver injury in BCG-primed mice via bystander activation of CD8+T cells.
Helicobacter pyloriwith a Truncated Lipopolysaccharide O Chain Fails To Induce Gastritis in SCID Mice Injected with Splenocytes from Wild-Type C57BL/6J Mice
Authors: Eaton K. A. , Logan S. M. , Baker P. E. , Peterson R. A. , Monteiro M. A. , Altman E.
Published: June 2004

The goal of this study was to determine whetherHelicobacter pylorilipopolysaccharide (LPS) O-chain polysaccharide contributes to gastritis in a mouse model. C57BL/6J or C57BL/6-Prkdcscid(severe combined immunodeficient [SCID]) mice were inoculated withH. pyloristrain SS1 or SS1::0826kan, in which a β-1,4-galactosyltransferase (HP0826), an LPS biosynthetic enzyme, had been disrupted.H. pyloristrain SS1::0826kan expresses truncated LPS lacking O chain. Recipient SCID mice were given C57BL/6J splenocytes by intraperitoneal injection. Bacterial colonization, gastric lesions (gastritis, neutrophilic infiltration, and gastric epithelial metaplasia), cellular (delayed-type hypersensitivity) and humoral immune responses toH. pylorisonicate, and gastric gamma interferon (IFN-γ) mRNA expression were quantified. Recipient SCID mice colonized byH. pyloristrain SS1 developed extensive gastritis with loss of normal fundic gland morphology. In contrast, gastric mucosa of recipient SCID mice colonized byH. pyloristrain SS1::0826kan was not statistically distinguishable from that of uninfected recipient mice. Delayed-type hypersensitivity and humoral immune responses were detected in infected mice inoculated with wild-type SS1, but not with SS1::0826kan. IFN-γ transcription was lower in mice infected with SS1::0826kan than in mice infected with SS1. In this model of rapidly progressive gastritis due toH. pylori, the O chain contributed to the extent of gastritis and to the host immune response. These data support a role forH. pyloriLPS O chain in direct induction of the host immune response leading to gastritis and gastric damage and are in contrast to protein antigens, such as urease andcagproducts which do not contribute to gastritis in mice.
Oral Vaccination withBrucella melitensisWR201 Protects Mice against Intranasal Challenge with VirulentBrucella melitensis16M
Authors: Izadjoo Mina J. , Bhattacharjee Apurba K. , Paranavitana Chrysanthi M. , Hadfield Ted L. , Hoover David L.
Published: June 2004

Human brucellosis can be acquired from infected animal tissues by ingestion, inhalation, or contamination of conjunctiva or traumatized skin by infected animal products. In addition,Brucellais recognized as a biowarfare threat agent. Although a vaccine to protect humans from natural or deliberate infection could be useful, vaccines presently used in animals are unsuitable for human use. We tested orally administered live, attenuated, purine auxotrophicB. melitensisWR201 bacteria for their ability to elicit cellular and humoral immune responses and to protect mice against intranasal challenge withB. melitensis16M bacteria. Immunized mice made serum antibody to lipopolysaccharide and non-O-polysaccharide antigens. Splenocytes from immunized animals released interleukin-2 and gamma interferon when grown in cultures withBrucellaantigens. Immunization led to protection from disseminated infection and enhanced clearance of the challenge inoculum from the lungs. Optimal protection required administration of live bacteria, was related to immunizing dose, and was enhanced by booster immunization. These results establish the usefulness of oral vaccination against respiratory challenge with virulentBrucellaand suggest that WR201 should be further investigated as a vaccine to prevent human brucellosis.
Synthetic Fragments ofVibrio choleraeO1 Inaba O-Specific Polysaccharide Bound to a Protein Carrier Are Immunogenic in Mice but Do Not Induce Protective Antibodies
Authors: Meeks Michael D. , Saksena Rina , Ma Xingquan , Wade Terri K. , Taylor Ronald K. , Kováč Pavol , Wade William F.
Published: June 2004

Development ofVibrio choleraelipopolysaccharide (LPS) as a cholera vaccine immunogen is justified by the correlation of vibriocidal anti-LPS response with immunity. TwoV. choleraeO1 LPS serotypes, Inaba and Ogawa, are associated with endemic and pandemic cholera. Both serotypes induce protective antibody following infection or vaccination. Structurally, the LPSs that define the serotypes are identical except for the terminal perosamine moiety, which has a methoxyl group at position 2 in Ogawa but a hydroxyl group in Inaba. The terminal sugar of the Ogawa LPS is a protective B-cell epitope. We chemically synthesized the terminal hexasaccharides ofV. choleraeserotype Ogawa, which comprises in part the O-specific polysaccharide component of the native LPS, and coupled the oligosaccharide at different molar ratios to bovine serum albumin (BSA). Our initial studies with Ogawa immunogens showed that the conjugates induced protective antibody. We hypothesized that antibodies specific for the terminal sugar of Inaba LPS would also be protective. Neoglycoconjugates were prepared from synthetic Inaba oligosaccharides (disaccharide, tetrasaccharide, and hexasaccharide) and BSA at different levels of substitution. BALB/c mice responded to the Inaba carbohydrate (CHO)-BSA conjugates with levels of serum antibodies of comparable magnitude to those of mice immunized with Ogawa CHO-BSA conjugates, but the Inaba-specific antibodies (immunoglobulin M [IgM] and IgG1) were neither vibriocidal nor protective in the infant mouse cholera model. We hypothesize that the anti-Inaba antibodies induced by the Inaba CHO-BSA conjugates have enough affinity to be screened via enzyme-linked immunosorbent assay but not enough to be protective in vivo.
S100 and Cytokine Expression in Caries
Authors: McLachlan Julia L. , Sloan Alastair J. , Smith Anthony J. , Landini Gabriel , Cooper Paul R.
Published: June 2004

The molecular immune response of the pulpal tissue during chronic carious infection is poorly characterized. Our objective was to examine the expression of potential molecular mediators of pulpal inflammation, correlate their levels with disease severity, and determine the cellular localization of key molecules. Results indicated that there was significantly increased transcriptional activity in carious compared to healthy pulp, and the increase correlated positively with disease severity. Semiquantitative reverse transcriptase PCR analysis in 10 carious and 10 healthy pulpal tissue samples of the S100 family members S100A8, S100A9, S100A10, S100A12, and S100A13; the cytokines tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), IL-8, IL-6, and epithelial cell-derived neutrophil attractant 78 (ENA-78); and the structural protein collagen-1α indicated that all genes tested, with the exception of S100A10, were more abundantly expressed in carious teeth. In addition, we found that the closer the carious lesion front was to the pulpal chamber the higher the expression was for all genes except S100A10. Multiple-regression analysis identified a significant positive correlation between the expression levels of S100A8 and IL-1β, ENA-78, and IL-6 and between collagen-1α and S100A8, TNF-α, IL-1β, IL-8, IL-6, and ENA-78. Immunohistochemical studies in carious pulpal tissue indicated that S100A8 and the S100A8/S100A9 complex were predominantly expressed by infiltrating neutrophils. Gene expression analyses in immune system cells supported these findings and indicated that bacterial activation of neutrophils caused upregulation of S100A8, S100A9, and S100A13. This study highlights the complex nature of the molecular immune response that occurs during carious infection.
Characterization of β-Glucan Recognition Site on C-Type Lectin, Dectin 1
Authors: Adachi Yoshiyuki , Ishii Takashi , Ikeda Yoshihiko , Hoshino Akiyoshi , Tamura Hiroshi , Aketagawa Jun , Tanaka Shigenori , Ohno Naohito
Published: June 2004

Dectin 1 is a mammalian cell surface receptor for (1→3)-β-d-glucans. Since (1→3)-β-d-glucans are commonly present on fungal cell walls, it has been suggested that dectin 1 is important for recognizing fungal invasion. In this study we tried to deduce the amino acid residues in dectin 1 responsible for β-glucan recognition. HEK293 cells transfected with mouse dectin 1 cDNA could bind to a gel-forming (1→3)-β-d-glucan, schizophyllan (SPG). The binding of SPG to a dectin 1 transfectant was inhibited by pretreatment with other β-glucans having a (1→3)-β-d-glucosyl linkage but not by pretreatment with α-glucans. Dectin 1 has a carbohydrate recognition domain (CRD) consisting of six cysteine residues that are highly conserved in C-type lectins. We prepared 32 point mutants with mutations in the CRD and analyzed their binding to SPG. Mutations at Trp221and His223resulted in decreased binding to β-glucan. Monoclonal antibody 4B2, a dectin- 1 monoclonal antibody which had a blocking effect on the β-glucan interaction, completely failed to bind the dectin-1 mutant W221A. A mutant with mutations in Trp221and His223did not have a collaborative effect on Toll-like receptor 2-mediated cellular activation in response to zymosan. These amino acid residues are distinct from residues in other sugar-recognizing peptide sequences of typical C-type lectins. These results suggest that the amino acid sequence W221-I222-H223 is critical for formation of a β-glucan binding site in the CRD of dectin 1.
Contribution of Gene Loss to the Pathogenic Evolution of
Burkholderia pseudomallei
and
Burkholderia mallei
Authors: Moore Richard A. , Reckseidler-Zenteno Shauna , Kim Heenam , Nierman William , Yu Yan , Tuanyok Apichai , Warawa Jonathan , DeShazer David , Woods Donald E.
Published: June 2004

Burkholderia pseudomallei
is the causative agent of melioidosis.
Burkholderia thailandensis
is a closely related species that can readily utilize
l
-arabinose as a sole carbon source, whereas
B. pseudomallei
cannot. We used Tn
5
-OT182 mutagenesis to isolate an arabinose-negative mutant of
B. thailandensis
. Sequence analysis of regions flanking the transposon insertion revealed the presence of an arabinose assimilation operon consisting of nine genes. Analysis of the
B. pseudomallei
chromosome showed a deletion of the operon from this organism. This deletion was detected in all
B. pseudomallei
and
Burkholderia mallei
strains investigated. We cloned the
B. thailandensis
E264 arabinose assimilation operon and introduced the entire operon into the chromosome of
B. pseudomallei
406e via homologous recombination. The resultant strain,
B. pseudomallei
SZ5028, was able to utilize
l
-arabinose as a sole carbon source. Strain SZ5028 had a significantly higher 50% lethal dose for Syrian hamsters compared to the parent strain 406e. Microarray analysis revealed that a number of genes in a type III secretion system were down-regulated in strain SZ5028 when cells were grown in
l
-arabinose, suggesting a regulatory role for
l
-arabinose or a metabolite of
l
-arabinose. These results suggest that the ability to metabolize
l
-arabinose reduces the virulence of
B. pseudomallei
and that the genes encoding arabinose assimilation may be considered antivirulence genes. The increase in virulence associated with the loss of these genes may have provided a selective advantage for
B. pseudomallei
as these organisms adapted to survival in animal hosts.
Response of the Splenic Dendritic Cell Population to Malaria Infection
Authors: Leisewitz Andrew L. , Rockett Kirk A. , Gumede Bonginkosi , Jones Margaret , Urban Britta , Kwiatkowski Dominic P.
Published: June 2004

Dendritic cells, particularly those residing in the spleen, are thought to orchestrate acquired immunity to malaria, but it is not known how the splenic dendritic cell population responds to malaria infection and how this response compares with the responses of other antigen-presenting cells. We investigated this question forPlasmodium chabaudiAS infection in C57BL/6 mice. We found that dendritic cells, defined here by the CD11c marker, migrated from the marginal zone of the spleen into the CD4+T-cell area within 5 days after parasites entered the bloodstream. This contrasted with the results observed for the macrophage and B-cell populations, which expanded greatly but did not show any comparable migration. Over the same time period dendritic cells showed upregulation of CD40, CD54, and CD86 costimulatory molecules that are required for successful T-cell activation. In dendritic cells, the peak intracellular gamma interferon expression (as shown by fluorescence-activated cell sorting) was on day 5, 2 days earlier than the peak expression in B-cells or macrophages. These findings show that splenic dendritic cells are actively engaged in the earliest phase of malarial infection in vivo and are likely to be critical in shaping the subsequent immune response.
Transcriptional Responses of Intestinal Epithelial Cells to Infection with
Vibrio cholerae
Authors: Stokes Neil R. , Zhou Xin , Meltzer Stephen J. , Kaper James B.
Published: June 2004

Vibrio cholerae
is a noninvasive enteric bacterium that causes the severe diarrheal disease cholera. Candidate cholera vaccines have been engineered by deleting genes encoding known virulence factors in
V. cholerae
; however, many of these attenuated strains were still reactogenic in human volunteers. In this study, DNA arrays were utilized to monitor the transcriptional responses of human intestinal epithelial cells (T84) to eight strains of
V. cholerae
, including attenuated, toxigenic, and environmental isolates. cDNA probes generated from host RNA samples were hybridized against low- and high-density gene arrays.
V. cholerae
induced the transcription of a variety of host genes and repressed the expression of a lower number of genes. Expression patterns were confirmed for certain genes by reverse transcriptase PCR and enzyme-linked immunosorbent assays. A core subset of genes was found to be differentially regulated in all experiments. These genes included genes involved in innate mucosal immunity, intracellular signaling, and cellular proliferation. Reactogenic vaccine strains induced greater expression of genes for certain proinflammatory cytokines than nonreactogenic strains. Wild-type and attenuated derivatives induced and repressed many genes in common, although there were differences in the transcription profiles. These results indicate that the types of host genes modulated by attenuated
V. cholerae
, and the extent of their induction, may mediate the symptoms seen with reactogenic cholera vaccine strains.
Nontypeable
Haemophilus influenzae
Strain 2019 Produces a Biofilm Containing
N
-Acetylneuraminic Acid That May Mimic Sialylated O-Linked Glycans
Authors: Greiner L. L. , Watanabe H. , Phillips N. J. , Shao J. , Morgan A. , Zaleski A. , Gibson B. W. , Apicella M. A.
Published: June 2004

Previous studies suggested that nontypeable
Haemophilus influenzae
(NTHI) can form biofilms during human and chinchilla middle ear infections. Microscopic analysis of a 5-day biofilm of NTHI strain 2019 grown in a continuous-flow chamber revealed that the biofilm had a diffuse matrix interlaced with multiple water channels. Our studies showed that biofilm production was significantly decreased when a chemically defined medium lacking
N
-acetylneuraminic acid (sialic acid) was used. Based on these observations, we examined mutations in seven NTHI strain 2019 genes involved in carbohydrate and lipooligosaccharide biosynthesis. NTHI strain 2019 with mutations in the genes encoding CMP-
N
-acetylneuraminic acid synthetase (
siaB
), one of the three NTHI sialyltransferases (
siaA
), and the undecaprenyl-phosphate α-
N
-acetylglucosaminyltransferase homolog (
wecA
) produced significantly smaller amounts of biofilm. NTHI strain 2019 with mutations in genes encoding phosphoglucomutase (
pgm
), UDP-galactose-4-epimerase, and two other NTHI sialyltransferases (
lic3A
and
lsgB
) produced biofilms that were equivalent to or larger than the biofilms produced by the parent strain. The biofilm formed by the NTHI strain 2019
pgm
mutant was studied with
Maackia amurensis
fluorescein isothiocyanate (FITC)-conjugated and
Sambucus nigra
tetramethyl rhodamine isocyanate (TRITC)-conjugated lectins.
S. nigra
TRITC-conjugated lectin bound to this biofilm, while
M. amurensis
FITC-conjugated lectin did not.
S. nigra
TRITC-conjugated lectin binding was inhibited by incubation with α2,6-neuraminyllactose and by pretreatment of the biofilm with
Vibrio cholerae
neuraminidase. Matrix-assisted laser desorption ionization—time of flight mass spectometry analysis of lipooligosaccharides isolated from a biofilm, the planktonic phase, and plate-grown organisms showed that the levels of most sialylated glycoforms were two- to fourfold greater when the lipooligosaccharide was derived from planktonic or biofilm organisms. Our data indicate that NTHI strain 2019 produces a biofilm containing α2,6-linked sialic acid and that the sialic acid content of the lipooligosaccharides increases concomitant with the transition of organisms to a biofilm form.
Multivariate Analysis of Cytokine Responses Identifies Distinctive Sensitivities to Lipopolysaccharide in Humans
Authors: Duncan David D. , Tiberio Lorrie , Eldridge John H.
Published: June 2004

We describe methods to identify high and low responders in a whole-blood assay of lipopolysaccharide-stimulated cytokine responses. Two multivariate measures of the cytokine responses both captured high and low responses for each of the four individual cytokines that were assayed.
Chlamydia trachomatis
Lacks an Adaptive Response to Changes in Carbon Source Availability
Authors: Nicholson Tracy L. , Chiu Karen , Stephens Richard S.
Published: June 2004

Most bacteria coordinately regulate gene expression as an adaptive response to a variety of environmental changes. One key environmental cue is the carbon source necessary for central metabolism. We used microarray analysis to monitor the global transcriptional response of the obligate intracellular pathogen
Chlamydia trachomatis
to the presence of glycolytic and gluconeogenic carbon sources. In contrast to free-living bacteria, changing the carbon source from glucose to glutamate or α-ketoglutarate had little effect on the global gene transcription of
C. trachomatis
.
Function of the Fibronectin-Binding Serum Opacity Factor ofStreptococcus pyogenesin Adherence to Epithelial Cells
Authors: Oehmcke Sonja , Podbielski Andreas , Kreikemeyer Bernd
Published: June 2004

The serum opacity factor (SOF) ofStreptococcus pyogenesis a serotyping tool and pathogenesis factor. Using SOF-coated latex beads in cell adherence assays and antiserum directed against SOF inS. pyogenes-HEp-2 cell adherence inhibition experiments, we demonstrate SOF involvement in the fibronectin-mediated adherence ofS. pyogenesto epithelial cells. SOF exclusively targets the 30-kDa N-terminal region of fibronectin. The interaction revealed association and dissociation constants 1 order of magnitude lower than those of otherS. pyogenesfibronectin-binding proteins.
Effect of micro-nutrients in anaerobic degradation of sulfate laden organics
Authors: Patidar S K , Tare Vinod
Published: June 2004

The effect of micro-nutrients, such as Fe, Ni, Zn, Co, and Mo, on anaerobic degradation of sulfate laden organics was investigated using bench-scale models of upflow anaerobic sludge blanket (UASB) reactor, anaerobic baffled reactor (ABR), and hybrid anaerobic baffled reactor (HABR), operating in varying conditions in ten phases (organic loading of 1.9–5.75 kg COD/(m3·d), sulfate loading of 0.54–1.88 kg SO42–/(m3·d), chemical oxygen demand (COD):SO42–ratio of 2.0–8.6). In the initial phase, no nutrient limitation was observed with COD removal of more than 94% in all three systems. Subsequently, increase in sulfate loading resulted in Ni and Co limitation and their supplementation restored COD removal in UASB system. However, baffled systems did not recover because of severe inhibition by sulfide. Results indicate that precipitation of nutrients could seriously deteriorate process performance, leading to failure even before sulfide concentration attains toxic level. The limitation of Fe coupled with high sulfate loading (1.88 kg SO42–/(m3·d)) resulted in growth of low-density, fragile, hollow, and granular biomass in UASB that washed out and caused process instability. Supplementation of Fe with other nutrients stabilized UASB process and also improved COD removal.Key words: anaerobic degradation, nutrients, UASB, ABR, HABR, sulfide toxicity, sulfate laden organics.
Index velocity methods for winter discharge measurement
Authors: Healy D , Hicks F E
Published: June 2004

At present, the only truly accurate method of determining discharge under ice-affected conditions is by direct measurement. However, this is a costly undertaking that places technicians at personal risk. Because of this, the Water Survey of Canada often bases winter discharge hydrographs on as few as two direct measurements over the entire ice-affected season. This study explores the viability of using an index velocity approach to winter discharge measurement, which basically involves the determination of streamflow based on a very limited number of actual point velocity measurements in the cross section. Such an approach has the potential to reduce the amount of time required for a single discharge measurement, thus opening the potential for an increase in the number of discharge measurements that can be obtained per year at a given site. Also, a reduction in personal risk to those taking measurements on the ice cover is expected because of the reduction in the time spent on the ice cover for each individual measurement. Here, the viability of using a single point velocity, or alternatively a single panel velocity profile, is explored using detailed velocity measurement data collected by the Water Survey of Canada at a number of sites across Canada, on rivers of varying size. Results suggest that there is a definite potential to streamline winter discharge measurement protocols to increase both safety and frequency of measurement.Key words: winter streamflow measurement, rivers, ice.
Flexural strengthening of precast reinforced concrete bridge girders using bonded carbon fibre reinforced polymer strips or external post-tensioning
Authors: Sayed-Ahmed Ezzeldin Y , Riad Amr H , Shrive Nigel G
Published: June 2004

Strengthening of reinforced concrete bridge girders has become a major concern. Many reinforced concrete highway bridges were constructed in Canada using precast reinforced concrete girders, and currently many of them need rehabilitation. Thus, two techniques for flexural strengthening of precast reinforced concrete bridge girders (HC-type) were investigated experimentally. The first technique involved bonding carbon fibre reinforced polymer (CFRP) strips to the soffits of the girders. The second technique was classical external post-tensioning with steel bars. A simple, yet innovative method was developed for applying the external prestressing to these girders. The experimental investigation was performed on full-scale girders from a dismantled bridge in Alberta (Canada). Outcomes of the experimental investigation led to the conclusion that classical methods of flexural strengthening (e.g., external prestressing) should not be completely disregarded. Also, an additional mode of failure needs to be added to currently available prediction models for estimating the gain in flexural strength of reinforced concrete girders retrofitted using bonded CFRP strips.Key words: bridges, CFRP, flexure strengthening, precast girders, post tension, prestressing, rehabilitation.
Évaluation des méthodes réglementaires de détermination des déplacements sismiques par analyse dynamique non linéaire
Authors: Branci Taieb , Tiliouine Boualem
Published: June 2004

A study is carried out to evaluate the storey drift evaluation methods of the seismic code of Algeria (RPA 99) and France (PS 92) for multi-storey steel rigid-frame buildings with set-back towers. The evaluation is based on a comparison of the storey drift obtained from the procedures of codes with those obtained from the nonlinear dynamic analysis of the buildings with set-back and a uniform building served as a reference. The results of the nonlinear dynamic analysis show in particular that the code methods of RPA 99 and PS 92 lead generally to an underestimation of storey drifts for the "tower" portion but provide such estimates of those for the "base" portion.Key words: storey, drift, code, seismic, building, set-back, response, analysis.