bluuebunny/crossref_metadata_2025 huggingface dataset:
Vascular Tone Estimation in Patients Implanted with the AbioCor Implantable Replacement Heart
Authors: Kung Robert T.V. , Zhang Hong
Published: May 2004

Abstract:  The AbioCor implantable replacement heart provides continuous hydraulic pressure data that are used for control purposes. The magnitude of the end systolic pressure spikes are compared to a preset threshold and used for controlling motor speeds to maintain a full stroke on every beat. Portions of the diastolic pressures of the left and the right side are averaged and can be used for left–right balance control. The mean right diastolic pressure may be used for beat rate (cardiac output) control. The systolic and diastolic hydraulic pressures of the left and right side are correlatable to the respective afterload and preload pressures. More importantly, with known hydraulic pump pressure‐flow characteristics, cardiac output is derived. The slopes of the hydraulic pressure traces as a function of time are not used for control or monitoring purposes. However, the magnitudes and shapes of these slopes can provide information on the tones of a patient's vasculature. The ratio of the slope of the systolic pressure to that of the stroke volume yields the vascular tone given in mm Hg/cc. Due to pre‐existing pulmonary complications, some AbioCor patients have pulmonary vascular tones that are substantially higher than their respective aortic tones by as much as a factor of four. Pulmonary tones as high as 2 mm Hg/cc, or approximately ten times the normal tone, are recorded. The ratio of averages of the aortic to the pulmonary tone range between 2.2 and 0.25 in patients implanted with the AbioCor compared with a normal value of 5 in subjects without pre‐existing pulmonary diseases. The AbioCor implantable replacement heart's hydraulic drive system is capable of providing valuable physiological information, including estimates of physiological pressures, cardiac outputs, and vascular tones.
Effects of Customized Bicarbonate Buffered Solutions for Continuous Renal Replacement Therapies on Polymorphonuclear Leukocytes Function and Viability
Authors: Maccariello Elizabeth , Dalboni Maria A. , Draibe Sérgio A. , Rocha Eduardo , Santos Oscar Fernando Pavão dos , Santos Bento , Cendoroglo Miguel
Published: May 2004

Abstract:  It has previously been shown that the mixture of bicarbonate and calcium in the solutions used for continuous renal replacement therapy led to crystalization and significant changes in calcium concentration and pH. The aim of this study was to investigate the impact of bicarbonate/calcium and lactate/calcium solutions for Continuous Renal Replacement Therapies (CRRT) on the viability and function of polymorphonuclear cells (PMN). We tested four customized bicarbonate buffered solutions: single bag (bicarbonate and calcium mixed 24 h before testing), double bag (mixed immediately before testing), filtered single bag and double bag solutions, and a commercial lactate buffered solution. Blood from 6 volunteers was incubated with the solutions for 30 min followed by PMN isolation. After overnight incubation, viability, phagocytosis, and peroxide production by PMN were determined by flow cytometry. There was no difference between the test solutions with respect to PMN viability and function. Therefore, the presence of microcrystals and the consequent changes in electrolyte concentrations do not seem to impair PMN function.
Bridge‐to‐recovery from Acute Myocarditis in a 12‐year‐old Child
Authors: Hotz Holger , Linneweber Joerg , Dohmen Pascal M. , Vargas Ortrud , Braun Jan , Konertz Wolfgang
Published: May 2004

Abstract:  Fulminant myocarditis causes substantial morbidity and mortality, especially in children and young adults. Mechanical circulatory support has become the standard therapy to bridge patients with intractable heart failure to either transplantation or myocardial recovery. Yet, successful weaning from biventricular support with full recovery is extremely rare in the pediatric population. This report describes the successful use of the MEDOS HIA ventricular assist device to bridge a 12‐year‐old girl to myocardial recovery in a biventricular bypass configuration. The left and right ventricle were completely off‐loaded by the pumps and the device provided sufficient cardiac output to normalize end‐organ function. Anticoagulation was maintained with i.v. heparin infusion. No neurological complications were detectable and the pump system was free of any macroscopic thrombi. After 19 days of support, cardiac function had recovered and the patient was successfully weaned from the device. Following physical rehabilitation, the patient was discharged home.
Maintenance of Glucose‐sensitive Insulin Secretion of Cryopreserved Human Islets with University of Wisconsin Solution and Ascorbic Acid‐2 Glucoside
Authors: Arata Takashi , Okitsu Teru , Fukazawa Takuya , Ikeda Hideaki , Kobayashi Kazuya , Yong Chen , Kosaka Yoshikazu , Narushima Michiki , Matsuoka Junji , Yamamoto Itaru , Tanaka Noriaki , Lakey Jonathan R.T. , Kobayashi Naoya
Published: May 2004

Abstract:  Normal human islet cells are an ideal source for pancreas‐targeted cell therapies, but the availability of human donor pancreata for islet isolation is severely limited. To effectively utilize such scarce donor organs for cell therapies, it is crucial to develop an excellent isolation, effective cryopreservation, and efficient gene transfer techniques for the transportation of isolated cells. In the present study, we investigate the effect of University of Wisconsin (UW) solution and ascorbic acid‐2 glucoside (AA2G) on the cryopreservation of human islets. We also evaluate the gene transfer efficiency of a lentiviral vector expressing the E. coli LacZ gene, Lt‐NLS/LacZ, in human islets. Human islets were isolated with a standard digestion method at the University of Alberta. Isolated islets were transported to Japan for 40 h and then subjected to cryopreservation experiments. The following preservation solutions were tested: UW solution with 100 µg/mL of AA2G, UW solution, 100% fetal bovine serum (FBS), and CMRL supplemented with 10% FBS. Following three months of cryopreservation, the islets were thawed and analyzed for viability, glucose‐sensitive insulin secretion, proinsulin gene expression profile, and in vivo engraftment. The islets were also subjected to monolayer formation with 804G‐cell‐line‐derived extracellular matrix (ECM), followed by Lt‐NLS/LacZ transduction. The viability, morphology, glucose‐sensitive insulin secretion, proinsulin gene expression, and monolayer formation efficiency of the thawed cryopreserved islets are significantly better maintained by the use of UW solution. When AA2G (100 µg/mL) is combined with UW, such parameters are further improved. The adequate engraftment of UW + AA2G‐cryopreserved human islets is achieved in the liver of nude mice. Efficient Lt‐NLS/LacZ transduction is identified in monolayered islets cryopreserved with UW solution with AA2G. The present work demonstrates that the combination of UW solution with AA2G (100 µg/mL) would be a useful cryopreservation means for human islets. Human islets monolayer‐cultured with 804G‐derived ECM are efficiently transduced with a lentiviral vector Lt‐NLS/LacZ.
Centrifugal Blood Pump with a Hydraulically‐levitated Impeller for a Permanently Implantable Biventricular Assist Device
Authors: Watanabe Kuniyoshi , Ichikawa Seiji , Asai Toshimasa , Motomura Tadashi , Hata Atsushi , Ito Seiichi , Shinohara Toshiyuki , Tsujimura Shinichi , Glueck Julia A. , Oestmann Daniel J. , Nosé Yukihiko
Published: May 2004

Abstract:  A permanently implantable biventricular assist device (BVAD) system has been developed with a centrifugal pump which is activated by a hydraulically‐levitated impeller. The pump impeller floats hydraulically into the top contact position; this position prevents thrombus formation by creating a washout effect at the bottom bearing area, a common stagnant region. The pump was subjected to in vitro studies using a pulsatile mock circulation loop to confirm the impeller's top contact position and the swinging motion produced by the pulsation. Eleven in vivo BVAD studies confirmed that this swinging motion eliminated blood clot formation. Twenty‐one pumps im‐planted for up to three months did not reveal any thrombosis in the pumps or downstream organs. One exception was a right pump which was exposed to severe low flow due to the kinking of the outflow graft by the accidental pulling of the flow meter cable. Three ninety‐day BVAD studies were achieved without thrombus formation.
Review of Studies of Healing Touch
Authors: Wardell Diane Wind , Weymouth Kathryn F.
Published: May 2004

Purpose:

To review studies of healing touch and its implications for practice and research.

Design:

A review of the literature from published works, abstracts from conference proceedings, theses, and dissertations was conducted to synthesize information on healing touch. Works available until June 2003 were referenced.

Methods:

The studies were categorized by target of interventions and outcomes were evaluated.

Findings and Conclusions:

Over 30 studies have been conducted with healing touch as the independent variable. Although no generalizable results were found, a foundation exists for further research to test its benefits.
Joblessness and Homelessness as Precursors of Health Problems in Formerly Incarcerated African American Men
Authors: Cooke Cheryl L.
Published: May 2004

Purpose:To explore how joblessness and homelessness influence the health of men leaving prison.

Design:A qualitative study using semi‐structured interviews was conducted with 17 formerly incarcerated African American men. Participants were interviewed for 1‐2 hours in a private setting. Data were collected over 3 months in late 2001.

Methods:Questions were focused on the experiences of participants during incarceration and after release from prison. Discourse analysis was used to analyze the data.

Finding:Findings related to unemployment included, (a) being incarcerated was associated with decreased types of employment available after release from prison, (b) a history of incarceration altered how participants were able to conduct job searches, and (c) men who did well after release were those who were self‐employed. Findings related to homelessness showed that barriers in either systems or relationships interfered with finding homes.

Conclusions:If formerly incarcerated African American men are to reenter society in meaningful ways, steady, living‐wage employment and a stable living environment are needed for these men to be able to successfully reintegrate into both families and the larger society, and to avoid conditions that are precursors of health problems.
A Meta‐Analysis of Predictors of Positive Health Practices
Authors: Yarcheski Adela , Mahon Noreen E. , Yarcheski Thomas J. , Cannella Barbara L.
Published: May 2004

Purpose:

To identify predictors of positive health practices from empirical studies in which the Personal Lifestyle Questionnaire was used.

Methods:

Meta‐analysis to determine the magnitude of the relationships between each of the predictors identified and positive health practices. Fourteen predictors of positive health practices were identified in 37 studies published since 1983; a meta‐analysis was conducted on 14 predictors.

Results:

Eight predictors (loneliness, social support, perceived health status, self‐efficacy, future time perspective, self‐esteem, hope, and depression) had moderate effect sizes, and six (stress, education, marital status, age, income, and sex) had small effect sizes.

Conclusions:

Findings enable health care professionals and researchers designing intervention studies to use the strongest predictors identified in this meta‐analysis to promote positive health practices.
Physical Activity in Low‐Income Postpartum Women
Authors: Wilkinson Susan , Huang Chiu‐Mieh , Walker Lorraine O. , Sterling Bobbie Sue , Kim Minseong
Published: May 2004

Purpose:

To validate the 7‐day physical activity recall (PAR), including alternative PAR scoring algorithms, using pedometer readings with low‐income postpartum women, and to describe physical activity patterns of a low‐income population of postpartum women.

Methods:

Forty‐four women (13 African American, 19 Hispanic, and 12 White) from the Austin New Mothers Study (ANMS) were interviewed at 3 months postpartum. Data were scored alternatively according to the Blair (sitting treated as light activity) and Welk (sitting excluded from light activity and treated as rest) algorithms. Step counts based on 3 days of wearing pedometers served as the validation measure.

Findings:

Using the Welk algorithm, PAR components significantly correlated with step counts were: minutes spent in light activity, total activity (sum of light to very hard activity), and energy expenditure. Minutes spent in sitting were negatively correlated with step counts. No PAR component activities derived with the Blair algorithm were significantly related to step counts. The largest amount of active time was spent in light activity: 384.4 minutes with the Welk algorithm. Mothers averaged fewer than 16 minutes per day in moderate or high intensity activity. Step counts measured by pedometers averaged 6,262 (SD=2,712) per day.

Conclusions:

The findings indicate support for the validity of the PAR as a measure of physical activity with low‐income postpartum mothers when scored according to the Welk algorithm. On average, low‐income postpartum women in this study did not meet recommendations for amount of moderate or high intensity physical activity.
Using Technology to Promote Self‐Efficacy for Healthy Eating in Adolescents
Authors: Long JoAnn D. , Stevens Kathleen R.
Published: May 2004

Purpose:

To test the effects of a classroom and World Wide Web (WWW) educational intervention on self‐efficacy (SE) for healthy eating (HE) and to examine the relationship of the theoretical concepts in a hypothesized model of eating behavior in adolescents.

Design:

A quasiexperimental pretest, posttest design was used in a random sample of students in two junior high schools.

Methods:

The intervention consisted of a combination of 5 hours of Web‐based instruction and 10 hours of classroom curriculum, compared to nutrition education embedded in the standard school curriculum during a 1‐month period. Participants completed six questionnaires. Data were analyzed using descriptive statistics, t tests, and Pearson's r correlation coefficient.

Findings and Conclusions:

The intervention group had significantly higher scores for SE for fruits and vegetables, SE for lower fat, usual food choices, and dietary knowledge of fat compared to the control group. No difference was found between groups in food consumption. Self‐efficacy was significantly associated with dietary knowledge of lower fat, usual food choices, and was inversely associated with lower‐fat consumption in the hypothesized model of eating behavior. The intervention was tailored to the social and developmental preferences of adolescents and effectively increased SE for HE. The mediating role of SE in the hypothesized model of adolescent eating behavior warrants further investigation.
International Content of High‐Ranking Nursing Journals in the Year 2000
Authors: Dougherty Molly C. , Lin Shu‐Yuan , McKenna Hugh P. , Seers Kate
Published: May 2004

Purpose:

To evaluate the extent of an international perspective in publication in nursing journals.

Design:

Characteristics of 2,581 articles, authors of articles, and journals (editorial purpose and editorial team) of 42 high‐ranking nursing journals for the year 2000 were analyzed.

Methods:

The characteristics were assessed using seven operational definitions of “international.”

Findings:

Major findings were: (a) 747 (28.9%) articles were identified as international, of which (b) 705 (94.3%) were placed in the scholarly or empirical categories; (c) more articles were categorized as empirical in the international articles; more articles were categorized as scholarly among the noninternational articles; (d) 763 (79.3%) articles met an international definition based on author characteristics; and (e) 20 (47.6%) journals had international editorial teams.

Conclusions:

Nearly 30% of articles had international content. Articles with international content were more frequently databased than were noninternational articles. The study provides a baseline indication of the extent of international perspectives in published articles in nursing journals. The extent to which these international articles make substantial contributions to knowledge has yet to be discovered.
An Integrative Review of American Nurses' Perceived Cultural Self‐Efficacy
Authors: Coffman Maren J. , Shellman Juliette , Bernal Henrietta
Published: May 2004

Purpose:

To review use of the Cultural Self‐Efficacy Scale (CSES) and to summarize the cumulative findings.

Methods:

A combination of literature searches and questionnaires to those who have requested the scale indicated 26 known uses. Fifteen reported sufficient data for statistical analysis.

Findings:

Of the 26 known uses of the CSES, 8 were published in peer‐reviewed journals, 5 in dissertations, 8 in theses, and 3 as data sets only. Two additional theses were not retrievable for the study. On a 5‐point Likert‐type scale, nurses reported the highest degree of self‐efficacy with African American (3.1) and Hispanic (3.1) patients and the lowest with Asian American patients (2.4). Six of the reports include Cronbach's alpha coefficients, ranging from .86 to .98. In the final sample of 15 studies, nurses did not report feeling confident caring for patients from other cultures.

Conclusions:

Although the CSES has been used in many settings with over 3,000 nurses, inconsistencies in the data preclude specific conclusions. Further research is needed using consistent reporting practices and sufficient predictor variables to draw further conclusions regarding the scale's psychometric properties.
The Involvement of the Orbitofrontal Cortex in the Experience of Regret
Authors: Camille Nathalie , Coricelli Giorgio , Sallet Jerome , Pradat-Diehl Pascale , Duhamel Jean-René , Sirigu Angela
Published: May 2004

Facing the consequence of a decision we made can trigger emotions like satisfaction, relief, or regret, which reflect our assessment of what was gained as compared to what would have been gained by making a different decision. These emotions are mediated by a cognitive process known as counterfactual thinking. By manipulating a simple gambling task, we characterized a subject's choices in terms of their anticipated and actual emotional impact. Normal subjects reported emotional responses consistent with counterfactual thinking; they chose to minimize future regret and learned from their emotional experience. Patients with orbitofrontal cortical lesions, however, did not report regret or anticipate negative consequences of their choices. The orbitofrontal cortex has a fundamental role in mediating the experience of regret.
Wind as a Long-Distance Dispersal Vehicle in the Southern Hemisphere
Authors: Muñoz Jesús , Felicísimo Ángel M. , Cabezas Francisco , Burgaz Ana R. , Martínez Isabel
Published: May 2004

Anisotropic (direction-dependent) long-distance dispersal (LDD) by wind has been invoked to explain the strong floristic affinities shared among landmasses in the Southern Hemisphere. Its contribution has not yet been systematically tested because of the previous lack of global data on winds. We used global winds coverage from the National Aeronautics and Space Administration SeaWinds scatterometer to test whether floristic similarities of Southern Hemisphere moss, liverwort, lichen, and pteridophyte floras conform better with (i) the anisotropic LDD hypothesis, which predicts that connection by “wind highways” increases floristic similarities, or (ii) a direction-independent LDD hypothesis, which predicts that floristic similarities among sites increase with geographic proximity. We found a stronger correlation of floristic similarities with wind connectivity than with geographic proximities, which supports the idea that wind is a dispersal vehicle for many organisms in the Southern Hemisphere.
Antigen Bias in T Cell Cross-Priming
Authors: Wolkers Monika C. , Brouwenstijn Nathalie , Bakker Arnold H. , Toebes Mireille , Schumacher Ton N. M.
Published: May 2004

Activated CD8
+
T cells detect virally infected cells and tumor cells by recognition of major histocompatibility complex class I–bound peptides derived from degraded, endogenously produced proteins. In contrast, CD8
+
T cell activation often occurs through interaction with specialized antigen-presenting cells displaying peptides acquired from an exogenous cellular source, a process termed cross-priming. Here, we observed a marked inefficiency in exogenous presentation of epitopes derived from signal sequences in mouse models. These data indicate that certain virus- and tumor-associated antigens may not be detected by CD8
+
T cells because of impaired cross-priming. Such differences in the ability to cross-present antigens should form important considerations in vaccine design.
CD8
+
T Cell Cross-Priming via Transfer of Proteasome Substrates
Authors: Norbury Christopher C. , Basta Sameh , Donohue Keri B. , Tscharke David C. , Princiotta Michael F. , Berglund Peter , Gibbs James , Bennink Jack R. , Yewdell Jonathan W.
Published: May 2004

“Cross-priming” describes the activation of naïve CD8
+
T cells by professional antigen-presenting cells that have acquired viral or tumor antigens from “donor” cells. Antigen transfer is believed to be mediated by donor cell–derived molecular chaperones bearing short peptide ligands generated by proteasome degradation of protein antigens. We show here that cross-priming is based on the transfer of proteasome substrates rather than peptides. These findings are potentially important for the rational design of vaccines that elicit CD8
+
T cell responses.
Multiple Catenanes Derived from Calix[4]arenes
Authors: Wang Leyong , Vysotsky Myroslav O. , Bogdan Anca , Bolte Michael , Böhmer Volker
Published: May 2004

A multicatenane is described in which two belts consisting of four annelated rings attached to the wide rims of two calix[4]arenes are interwoven in such a way that each ring of one belt penetrates two adjacent rings of the other belt and vice versa. The key step of the synthesis of this [8]catenane is the exclusive formation of preorganized heterodimers between a multimacrocyclic tetraurea calix[4]arene and an “open-chain” tetraurea calix[4]arene containing eight ω-alkenyl groups. When a tetraurea calix[4]arene containing four alkenyl groups is used, a bis-[3]catenane is formed analogously.
Molecular Borromean Rings
Authors: Chichak Kelly S. , Cantrill Stuart J. , Pease Anthony R. , Chiu Sheng-Hsien , Cave Gareth W. V. , Atwood Jerry L. , Stoddart J. Fraser
Published: May 2004

The realization of the Borromean link in a wholly synthetic molecular form is reported. The self-assembly of this link, which is topologically achiral, from 18 components by the template-directed formation of 12 imine and 30 dative bonds, associated with the coordination of three interlocked macrocycles, each tetranucleating and decadentate overall, to a total of six zinc(II) ions, is near quantitative. Three macrocycles present diagonally in pairs, six
exo
-bidentate bipyridyl and six
endo
-diiminopyridyl ligands to the six zinc(II) ions. The use, in concert, of coordination, supramolecular, and dynamic covalent chemistry allowed the highly efficient construction, by multiple cooperative self-assembly processes, of a nanoscale dodecacation with an approximate diameter of 2.5 nanometers and an inner chamber of volume 250 Å
3
, lined with 12 oxygen atoms.
Degeneration and Regeneration of Murine Skeletal Neuromuscular Junctions after Intramuscular Injection with a Sublethal Dose of
Clostridium sordellii
Lethal Toxin
Authors: Barbier Julien , Popoff Michel R. , Molgó Jordi
Published: May 2004

Clostridium sordellii
lethal toxin (LT), a 250-kDa protein which is the bacteria's major virulence factor, belongs to a family of large clostridial cytotoxins which glucosylate small GTP-binding proteins. Here, we report the results of our ex vivo analysis of the structure and function of skeletal neuromuscular tissue obtained from mice at various times after intramuscular injection of a sublethal dose of LT (0.25 ng/g of body wt). The toxin caused, within 24 h, pronounced localized edema, inflammation, myofibril disassembly, and degeneration of skeletal muscle fibers in the injected area, and it glucosylated the muscle tissue's small GTPases. Regeneration of the damaged fibers was evident 6 to 9 days postinjury and was completed by 60 days. The expression of dystrophin, laminin, and fast and neonatal myosin in regenerating fibers, detected by immunofluorescence microscopy, confirmed that LT does not impair the high regenerative capacity of murine skeletal muscle fibers. Functional studies revealed that LT affects muscle contractility and neuromuscular transmission. However, partial recovery of nerve-evoked muscle twitches and tetanic contractions was observed by day 15 postinjection, and extensive remodeling of the neuromuscular junction's nerve terminals and clusters of muscle acetylcholine receptors was still evident 30 days postinjection. In conclusion, to the best of our knowledge, this is the first report to characterize the degeneration and regeneration of skeletal neuromuscular tissue after in vivo exposure to a large clostridial cytotoxin. In addition, our data may provide an explanation for the severe neuromuscular alterations accompanying wound infections caused by
C. sordellii
.
PneumocystisActivates Human Alveolar Macrophage NF-κB Signaling through Mannose Receptors
Authors: Zhang Jianmin , Zhu Jinping , Imrich Amy , Cushion Melanie , Kinane T. Bernard , Koziel Henry
Published: May 2004

Alveolar macrophages (AM) represent important effector cells in the innate immune response to the AIDS-related pathogenPneumocystis, but the early AM host defense signaling events are poorly defined. Using AM from healthy individuals, we showed in the present study thatPneumocystisorganisms stimulate AM NF-κB p50 and p65 nuclear translocation in a time-dependent and multiplicity-of-infection-dependent manner as determined by electrophoretic mobility shift assay and immunofluorescence microscopy and that NF-κB nuclear translocation is associated with I-κB phosphorylation. Importantly, competitive inhibition of mannose receptor and targeted short interfering RNA-mediated gene suppression of mannose receptor mRNA and protein is associated with complete elimination of NF-κB nuclear translocation in response toPneumocystis. Furthermore, human immunodeficiency virus (HIV) infection of AM (as a model human disease state of reduced AM mannose receptor expression and function) inhibitsPneumocystis-mediated NF-κB nuclear translocation and is associated with reduced I-κB phosphorylation and reduced interleukin-8 (IL-8) release. In contrast, NF-κB nuclear translocation and IL-8 release in response to lipopolysaccharide are intact in AM from both healthy and HIV-infected individuals, indicating that the observed impairment is not a global disturbance of the NF-κB pathway. Thus, in addition to phagocytic and endocytic effector functions, the present study identifies mannose receptors as pattern recognition receptors capable of NF-κB activation in response to infectious non-self challenge. AM mannose receptor-mediated NF-κB activation may represent an important mechanism of the host cell response toPneumocystis, and altered NF-κB activation in the context of HIV infection may impair a critical innate immune signaling response and may contribute to pathogenesis of opportunistic lung infections.
Myeloid Differentiation Antigen 88 Deficiency Impairs Pathogen Clearance but Does Not Alter Inflammation inBorrelia burgdorferi-Infected Mice
Authors: Liu Nengyin , Montgomery Ruth R. , Barthold Stephen W. , Bockenstedt Linda K.
Published: May 2004

The spirocheteBorrelia burgdorfericauses acute inflammation in mice that resolves with the development of pathogen-specific adaptive immunity.B. burgdorferilipoproteins activate innate immune cells via Toll-like receptor 2 (TLR2), but TLR2-deficient mice are not resistant toB. burgdorferi-induced disease, suggesting the involvement of other TLRs or non-TLR mechanisms in the induction of acute inflammation. For this study, we used mice that were deficient in the intracellular adapter molecule myeloid differentiation antigen 88 (MyD88), which is required for all TLR-induced inflammatory responses, to determine whether the interruption of this pathway would alterB. burgdorferi-induced disease. Infected MyD88−/−mice developed carditis and arthritis, similar to the disease in wild-type (WT) mice analyzed at its peak (days 14 and 28) and during regression (day 45). MyD88−/−macrophages produced tumor necrosis factor alpha only when spirochetes were opsonized, suggesting a role forB. burgdorferi-specific antibody in disease expression. MyD88−/−mice produced stronger pathogen-specific Th2-dependent immunoglobulin G1 (IgG1) responses than did WT mice, and their IgM titers remained significantly elevated through 90 days of infection. Despite specific antibodies, the pathogen burden was 250-fold higher in MyD88−/−mice than in WT mice 45 days after infection; by 90 days of infection, the pathogen burden had diminished substantially in MyD88−/−mice, but it was still elevated compared to that in WT mice. The elevated pathogen burden may be explained in part by the finding that MyD88−/−peritoneal macrophages could ingest spirochetes but degraded them more slowly than WT macrophages. Our results show that MyD88-dependent signaling pathways are not required forB. burgdorferi-induced inflammation but are necessary for the efficient control of the pathogen burden by phagocytes.
Virulent and Avirulent Strains ofFrancisella tularensisPrevent Acidification and Maturation of Their Phagosomes and Escape into the Cytoplasm in Human Macrophages
Authors: Clemens Daniel L. , Lee Bai-Yu , Horwitz Marcus A.
Published: May 2004

Francisella tularensis, the agent of tularemia, is an intracellular pathogen, but little is known about the compartment in which it resides in human macrophages. We have examined the interaction of a recent virulent clinical isolate ofF. tularensissubsp.tularensisand the live vaccine strain with human macrophages by immunoelectron and confocal immunofluorescence microscopy. We assessed the maturation of theF. tularensisphagosome by examining its acquisition of the lysosome-associated membrane glycoproteins (LAMPs) CD63 and LAMP1 and the acid hydrolase cathepsin D. Two to four hours after infection, vacuoles containing liveF. tularensiscells acquired abundant staining for LAMPs but little or no staining for cathepsin D. However, after 4 h, the colocalization of LAMPs with liveF. tularensisorganisms declined dramatically. In contrast, vacuoles containing formalin-killed bacteria exhibited intense staining for all of these late endosomal/lysosomal markers at all time points examined (1 to 16 h). We examined the pH of the vacuoles 3 to 4 h after infection by quantitative immunogold staining and by fluorescence staining for lysosomotropic agents. Whereas phagosomes containing killed bacteria stained intensely for these agents, indicating a marked acidification of the phagosomes (pH 5.5), phagosomes containing liveF. tularensisdid not concentrate these markers and thus were not appreciably acidified (pH 6.7). An ultrastructural analysis of theF. tularensiscompartment revealed that during the first 4 h after uptake, the majority ofF. tularensisbacteria reside within phagosomes with identifiable membranes. The cytoplasmic side of the membranes of ∼50% of these phagosomes was coated with densely staining fibrils of ∼30 nm in length. In many cases, these coated phagosomal membranes appeared to bud, vesiculate, and fragment. By 8 h after infection, the majority of liveF. tularensisbacteria lacked any ultrastructurally discernible membrane separating them from the host cell cytoplasm. These results indicate thatF. tularensisinitially enters a nonacidified phagosome with LAMPs but without cathepsin D and that the phagosomal membrane subsequently becomes morphologically disrupted, allowing the bacteria to gain direct access to the macrophagic cytoplasm. The capacity ofF. tularensisto alter the maturation of its phagosome and to enter the cytoplasm is likely an important element of its capacity to parasitize macrophages and has major implications for vaccine development.
RecombinantStreptococcus equiProteins Protect Mice in Challenge Experiments and Induce Immune Response in Horses
Authors: Flock Margareta , Jacobsson Karin , Frykberg Lars , Hirst Timothy R. , Franklin Anders , Guss Bengt , Flock Jan-Ingmar
Published: May 2004

Horses that have undergone infection caused byStreptococcus equisubspeciesequi(strangles) were found to have significantly increased serum antibody titers against three previously characterized proteins, FNZ (cell surface-bound fibronectin binding protein), SFS (secreted fibronectin binding protein), and EAG (α2-macroglobulin, albumin, and immunoglobulin G [IgG] binding protein) fromS. equi. To assess the protective efficacy of vaccination with these three proteins, a mouse model of equine strangles was utilized. Parts of the three recombinant proteins were used to immunize mice, either subcutaneously or intranasally, prior to nasal challenge withS. equisubsp.equi. The adjuvant used was EtxB, a recombinant form of the B subunit ofEscherichia coliheat-labile enterotoxin. It was shown that nasal colonization ofS. equisubsp.equiand weight loss due to infection were significantly reduced after vaccination compared with a mock-vaccinated control group. This effect was more pronounced after intranasal vaccination than after subcutaneous vaccination; nearly complete eradication of nasal colonization was obtained after intranasal vaccination (P< 0.001). When the same antigens were administered both intranasally and subcutaneously to healthy horses, significant mucosal IgA and serum IgG antibody responses against FNZ and EAG were obtained. The antibody response was enhanced when EtxB was used as an adjuvant. No adverse effects of the antigens or EtxB were observed. Thus, FNZ and EAG in conjunction with EtxB are promising candidates for an efficacious and safe vaccine against strangles.
Induction of Morphological and Electrophysiological Changes in Hamster Cornea after In Vitro Interaction with Trophozoites of
Acanthamoeba
spp
Authors: Omaña-Molina Maritza , Navarro-García Fernando , González-Robles Arturo , Serrano-Luna José de Jesús , Campos-Rodríguez Rafael , Martínez-Palomo Adolfo , Tsutsumi Víctor , Shibayama Mineko
Published: May 2004

Acanthamoeba castellani
and
Acanthamoeba polyphaga
are free-living amebae that cause keratitis and granulomatous encephalitis in humans. We have analyzed the early morphological and electrophysiological changes occurring during the in vitro interaction of cultured amebae with intact or physically damaged corneas obtained from hamsters. Both species of
Acanthamoeba
produced similar cytopathic changes, as seen by light microscopy and scanning electron microscopy. After adhesion to the epithelial surface, trophozoites formed clumps and migrated toward the cell borders, causing the separation of adjacent cells at 1 h of coculture. At later stages (2 to 4 h), some amebae were found under desquamating epithelial cells whereas others were seen associated with damaged cells or forming amebostome-like structures to ingest detached epithelial cells. Control corneas incubated in culture medium conditioned with amebae showed a cytoplasmic vacuolization and blurring of the epithelial-stromal junction. The early stages of corneal epithelial damage caused by amebae were also analyzed by measuring the transepithelial resistance changes in corneas mounted in Ussing chambers. Both species of
Acanthamoeba
caused a rapid decrease in electrical resistance. The present observations demonstrate that under in vitro conditions,
Acanthamoeba
trophozoites rapidly cause significant damage to the corneal epithelium. Furthermore, in our experimental model, previous physical damage to the corneas was not a prerequisite for the development of amebic corneal ulcerations.
Therapeutic Vaccination againstHelicobacter pyloriin the Beagle Dog Experimental Model: Safety, Immunogenicity, and Efficacy
Authors: Rossi Giacomo , Ruggiero Paolo , Peppoloni Samuele , Pancotto Laura , Fortuna Damiano , Lauretti Laura , Volpini Gianfranco , Mancianti Silvia , Corazza Michele , Taccini Ennio , Di Pisa Francesco , Rappuoli Rino , Del Giudice Giuseppe
Published: May 2004

Helicobacter pyloriis a gram-negative bacterium that colonizes the human gastric mucosa causing gastritis and peptic ulcer and increasing the risk of gastric cancer. The efficacy of current antibiotic-based therapies can be limited by problems of patient compliance and increasing antibiotic resistance; the vaccine approach can overcome these limits. The present study describes the therapeutic vaccination of experimentallyH. pylori-infected beagle dogs, an animal model that reproduces several aspects of the human infection withH. pylori. The vaccine consisted of three recombinantH. pyloriantigens, CagA, VacA, and NAP, formulated at different doses (10, 25, or 50 μg each) with alum and administered intramuscularly either weekly or monthly. No adverse effects were observed after vaccination and a good immunoglobulin G response was generated against each of the three antigens. Bacterial colonization and gastritis were decreased after the completion of the vaccination cycle, especially in the case of the monthly immunization schedule. In conclusion, therapeutic vaccination in the beagle dog model was safe and immunogenic and was able to limitH. pyloricolonization and the related gastric pathology.
Binding and Internalization of
Clostridium perfringens
Iota-Toxin in Lipid Rafts
Authors: Nagahama Masahiro , Yamaguchi Akiwo , Hagiyama Tohko , Ohkubo Noriko , Kobayashi Keiko , Sakurai Jun
Published: May 2004

Clostridium perfringens
iota-toxin is a binary toxin composed of an enzymatic component (Ia) and a binding component (Ib). The oligomer of Ib formed in membranes induces endocytosis. We examined the binding and internalization of Ib by using Cy3-labeled Ib. Labeled Ib was retained at the membranes of MDCK cells for 60 min of incubation at 37°C, and later it was detected in cytoplasmic vesicles. To determine whether Ib associates with lipid rafts, we incubated MDCK cells with Ib at 4 or 37°C and fractionated the Triton-insoluble membranes. An Ib complex of 500 kDa was localized at 37°C to the insoluble fractions that fulfilled the criteria of lipid rafts, but it did not form at 4°C. The amount of complex in the raft fraction reached a maximum after 60 min of incubation at 37°C. When the cells that were preincubated with Ib at 4°C were incubated at 37°C, the complex was detected in the raft fraction. The treatment of MDCK cells with methyl-β-cyclodextrin reduced the localization of the Ib complex to the rafts and the rounding of the cells induced by Ia plus Ib. When
125
I-labeled Ia was incubated with the cells in the presence of Ib at 37°C, it was localized in the raft fraction. Surface plasmon resonance analysis revealed that Ia binds to the oligomer of Ib. We conclude that Ib binds to a receptor in membranes and then moves to rafts and that Ia bound to the oligomer of Ib formed in the rafts is internalized.
Tyrosine Kinase Inhibition Reduces Inflammation in the Acute Stage of Experimental Pneumococcal Meningitis
Authors: Angstwurm Klemens , Hanisch Uwe-Karsten , Gassemi Tarraneh , Bille Margrethe Bastholm , Prinz Marco , Dirnagl Ulrich , Kettenmann Helmut , Weber Joerg R.
Published: May 2004

Bacterial meningitis is an acute inflammatory disease of the central nervous system with a mortality rate of up to 30%. Excessive stimulation of the host immune system by bacterial surface components contributes to this devastating outcome. In vitro studies have shown that protein tyrosine kinase inhibitors are highly effective in preventing the release of proinflammatory cytokines induced by pneumococcal cell walls in microglia. In a well-established rat model, intracisternal injection of purified pneumococcal cell walls induced meningitis characterized by increases in the regional cerebral blood flow and intracranial pressure, an influx of leukocytes, and high concentrations of tumor necrosis factor alpha (TNF-α) in the cerebrospinal fluid. Compared with the values at the beginning of the experiment, intraperitoneal injection of tyrphostin AG 126 reduced the increases in regional cerebral blood flow (at 6 h, 127% ± 14% versus 222% ± 51% of the baseline value;P< 0.05) and intracranial pressure (at 6 h, 0.8 ± 2.4 versus 5.4 ± 2.0 mm of Hg;P< 0.05), the influx of leukocytes (at 6 h, 1,336 ± 737 versus 4,350 ± 2,182 leukocytes/μl;P< 0.05), and the TNF-α concentration (at 6 h, 261 ± 188 versus 873 ± 135 pg/μl;P< 0.05). These results demonstrate that inhibition of AG 126-sensitive tyrosine kinase pathways may provide new approaches for preventing excessive inflammation and reducing the increases in blood flow and intracranial pressure in the acute phase of bacterial meningitis.
Bacterial Probiotic Modulation of Dendritic Cells
Authors: Drakes Maureen , Blanchard Thomas , Czinn Steven
Published: May 2004

Intestinal dendritic cells are continually exposed to ingested microorganisms and high concentrations of endogenous bacterial flora. These cells can be activated by infectious agents and other stimuli to induce T-cell responses and to produce chemokines which recruit other cells to the local environment. Bacterial probiotics are of increasing use against intestinal disorders such as inflammatory bowel disease. They act as nonpathogenic stimuli within the gut to regain immunologic quiescence. This study was designed to determine the ability of a bacterial probiotic cocktail VSL#3 to alter cell surface antigen expression and cytokine production in bone marrow-derived dendritic cell-enriched populations. Cell surface phenotype was monitored by monoclonal fluorescent antibody staining, and cytokine levels were quantitated by enzyme-linked immunosorbent assay. High-dose probiotic upregulated the expression of C80, CD86, CD40, and major histocompatibility complex class II I-Ad. Neither B7-DC or B7RP-1 was augmented after low-dose probiotic orLactobacillus caseitreatment, but B7RP-1 showed increased expression on dendritic cells stimulated with the gram-negative bacteriumEscherichia coli. Functional studies showed that probiotic did not enhance the ability of dendritic cells to induce allogeneic T-cell proliferation, as was observed forE. coli. Substantial enhancement of interleukin-10 release was observed in dendritic cell-enriched culture supernatants after 3 days of probiotic stimulation. These results demonstrate that probiotics possess the ability to modulate dendritic cell surface phenotype and cytokine release in granulocyte-macrophage colony-stimulating factor-stimulated bone marrow-derived dendritic cells. Regulation of dendritic cell cytokines by probiotics may contribute to the benefit of these molecules in treatment of intestinal diseases.
Associations between Responses to the Rhoptry-Associated Membrane Antigen of
Plasmodium falciparum
and Immunity to Malaria Infection
Authors: Topolska Agnieszka E. , Richie Thomas L. , Nhan Doan Hanh , Coppel Ross L.
Published: May 2004

Rhoptry proteins participate in the invasion of red blood cells by merozoites during the malaria parasite's asexual-stage cycle. Interference with the rhoptry protein function has been shown to prevent invasion, and three rhoptry proteins have been suggested as potential components of a vaccine against malaria. Rhoptry-associated membrane antigen (RAMA) is a 170-kDa protein of
Plasmodium falciparum
which is processed to a 60-kDa mature form in the rhoptries. p60/RAMA is discharged from rhoptries of free merozoites and binds to the red-cell membrane before being internalized to form part of the parasitophorous vacuole of the newly developing ring. We examined the range of anti-RAMA responses in individuals living in an area of endemicity for malaria and determined its association with clinical immunity. RAMA is immunogenic during infections, and at least three epitopes within RAMA are recognized by hyperimmune sera in immunoblots. Sera from individuals living in a region of Vietnam where malaria is endemic possessed strong antibody responses toward two C-terminal regions of RAMA. Cytophilic antibody isotypes (immunoglobulin G1 [IgG1] and IgG3) predominated in humoral responses to both C-terminal epitopes. Acute episodes of
P. falciparum
infection result in significant boosting of levels of antibody to an epitope at the extreme C terminus of RAMA that harbors the red-cell-binding domain. Immunity to
P. falciparum
infection was linked to elevated levels of IgG3 responses to this functional domain of RAMA, suggesting that the region may contain a protective epitope useful for inclusion in a multiepitope vaccine against malaria.
Mucosal Vaccine Made from Live, RecombinantLactococcus lactisProtects Mice against Pharyngeal Infection withStreptococcus pyogenes
Authors: Mannam Praveen , Jones Kevin F. , Geller Bruce L.
Published: May 2004

A novel vaccine (LL-CRR) made from live, nonpathogenicLactococcus lactisthat expresses the conserved C-repeat region (CRR) of M protein fromStreptococcus pyogenesserotype 6 was tested in mice. Nasally vaccinated mice produced CRR-specific salivary immunoglobulin A (IgA) and serum IgG. Subcutaneously vaccinated mice produced CRR-specific serum IgG but not salivary IgA. A combined regimen produced responses similar to the salivary IgA of nasally vaccinated mice and serum IgG of subcutaneously vaccinated mice. Mice vaccinated nasally or with the combined regimen were significantly protected against pharyngeal infection following a nasal challenge withS. pyogenesM serotype 14. Mice vaccinated subcutaneously were not protected against pharyngeal infection. Mice in all three LL-CRR vaccination groups were significantly protected against the lethal effects ofS. pyogenes. Only 1 of 77 challenged mice that were vaccinated with LL-CRR died, whereas 60 of 118 challenged mice that were vaccinated with a control strain or phosphate-buffered saline died. In conclusion, mucosal vaccination with LL-CRR produced CRR-specific salivary IgA and serum IgG, prevented pharyngeal infection withS. pyogenes, and promoted survival.
Surface Plasmon Resonance Analysis of Antipolysaccharide Antibody Specificity: Responses to Meningococcal Group C Conjugate Vaccines and Bacteria
Authors: García-Ojeda Pablo A. , Hardy Sharon , Kozlowski Steven , Stein Kathryn E. , Feavers Ian M.
Published: May 2004

Antibody (Ab) responses to polysaccharides (PS), such asNeisseria meningitidisgroup C PS (MCPS), are characterized as being thymus independent and are restricted with regard to clonotype and isotype expression. PS conjugated to proteins, e.g., MCPS coupled with tetanus toxoid or the diphtheria toxin derivative CRM197, elicit thymus-dependent responses. The present study developed a surface plasmon resonance approach to evaluate Ab responses to MCPS conjugate vaccines, including either O-acetylated (OAc+) or de-O-acetylated (OAc−) forms of the PS. The results were generally consistent with those obtained by enzyme-linked immunosorbent assay and showed that sera from mice immunized with conjugate vaccines contain Abs that bind more effectively to OAc+and OAc−MCPS than sera from mice immunized with fixed bacteria. The data suggest a critical shared or overlapping epitope recognized by all the conjugate vaccine immune sera and strategies for assessing polyclonal Ab avidity.