bluuebunny/crossref_metadata_2025 huggingface dataset:
The inhibition of the viability of myeloma cells and the production of cytokine by two strains of Lactobacillus sakei from meat
Authors: Haza Ana Isabel , Zabala Adriana , Arranz Nuria , García Almudena , Morales Paloma
Published: March 2005

Ten strains of lactic acid bacteria were isolated from a dry fermented sausage and tested for stimulation or inhibition of the viability of Vero and myeloma cells. They did not significantly affect the viability of Vero cells but two isolates (CBL/H and CBL/K) showed a strong and moderate inhibition of the myeloma cell viability (at 108 CFU mL−1, 17.6 and 33.2%, respectively, survival of myeloma cells). The isolates were identified as Lactobacillus sakei by DNA sequencing of the 16S rRNA products of a polymerase chain reaction. No protective effect was found, at the concentrations used, against cytotoxicity of N‐nitrosamines. To test the effect of L. sakei CBL/H and CBL/K on cytokine production [tumour necrosis factor alpha (TNF‐α), interleukin‐1β (IL‐1β) and interleukin‐8 (IL‐8)], the human macrophage cell line (THP‐1) was cultured in the presence and absence of lipopolysaccharide (LPS). Lactobacillus sakei CBL/H and CBL/K induced IL‐1β and IL‐8 release when cells were stimulated with and without LPS. However there was TNF‐α release only in the presence of the LPS.
Trehalose improves flavour retention in dehydrated apricot puree
Authors: Komes Draženka , Lovrić Tomislav , Kovačević Ganić Karin , Gajdoš Kljusurić Jasenka , Banović Mara
Published: March 2005

The influence of the addition of two sugars (trehalose and sucrose) on the retention of volatiles responsible for the characteristic aroma in dehydrated apricot puree was studied. Aroma compounds of fresh and both freeze‐dried and foam‐mat‐dried apricot puree were analysed by manual headspace solid‐phase microextraction coupled with gas chromatography (GC‐FID and GC‐MS). The best retention of aroma compounds in dehydrated apricot puree was obtained when trehalose was added, regardless of the dehydration process used (freeze drying or foam‐mat drying), although, generally, a much higher retention of flavour volatiles was obtained in freeze‐dried purees. Principal Component Analysis and Cluster Analysis were applied to all the apricot purees studied to obtain a simplified view of the relationship among the aroma compounds in dehydrated apricot purees. This study gives further insights into the mechanisms that occur when trehalose is applied as an additive and will enable the development of new processes to maximize this effect and to produce superior dried products.
Descending Thoracic Aortic Aneurysm Repair With the Aid of Partial Cardiopulmonary Bypass: Heparin‐coated Circuits Versus Nonheparin‐coated Circuits
Authors: Morishita Kiyofumi , Kawaharada Nobuyoshi , Fukada Johji , Hachiro Yoshikazu , Kurimoto Yoshihiko , Fujisawa Yasuaki , Saito Tatsuya , Abe Tomio
Published: March 2005

Abstract:  Background: We have performed descending thoracic aortic aneurysm repairs with partial cardiopulmonary bypass, including heparin‐coated circuits. The aim of this study was to evaluate (i) the impact of partial cardiopulmonary bypass on distal organ function and surgical outcomes; and (ii) the effectiveness of using heparin‐coated circuits for preventing bleeding complications. Methods: From July 1980 to June 2004, 309 patients underwent descending thoracic aortic aneurysm repairs using partial cardiopulmonary bypass. Their mean age was 61 years (range 19–81 years). One hundred of the 309 patients underwent repair of descending thoracic aortic aneurysm with heparin‐coated circuits. Blood data for renal and hepatic function were collected on the day before the operation and postoperative days. Results: The in‐hospital mortality was 15%. Distal organ dysfunction included spinal cord dysfunction in 2 patients (0.7%) and renal failure necessitating hemodialysis in 15 patients (5%, 15/297: excluded 12 dialysis patients). Multivariate analyses showed that preoperative hemodialysis and emergency operation were risk factors for operative mortality and that emergency operation was a risk factor for requiring hemodialysis. Renal and hepatic function normalized by 2 weeks after surgery. There were no significant differences between the heparin‐coated group and nonheparin‐coated group in amounts of packed red cells, fresh frozen plasma, and platelets transfused during the procedures. Conclusions: Our data showed that partial cardiopulmonary bypass is a safe and effective method for distal perfusion. Using this technique, descending thoracic aortic aneurysm repair can be performed with acceptable mortality and morbidity. However, the superiority of heparin‐coated circuits over nonheparin‐coated ones was not proved.
Impact of Inverse Plasma Filtration on Complement Activation in Porcine Blood
Authors: Haltern Claudia , Kirschfink Michael , Rossaint Rolf , Unger Juliane K.
Published: March 2005

Abstract:  During extracorporeal circulation, activation of the complement system as a bioincompatibility reaction upon contact with artificial surfaces is well known. This may induce adverse effects for the patient as well as for the bioreactor when using a hybrid liver support system. At present, the achievable clearance rates in hybrid liver support systems are restricted by the limitations of blood flow through the capillaries of the plasma filter. In order to enhance clearance rates it is desirable to develop a high‐flow plasma separation unit in which the activation of the complement system is as low as possible. Conventional plasma filters operating in normal and in inverse (blood flow around the capillaries and the capillary lumen serving as plasma compartment) modes were investigated applying an in vitro circuit (n = 4 in each group). For this purpose heparinized porcine blood was used. Complement activation was measured as generation of the soluble membrane attack complex, SC5b‐9. With a normal flow mode the maximum achievable filtration rates varied from 25 to 40 mL/min, whereas the maximal filtration rates with an inverse flow mode varied from 40 to 100 mL/min. While these values were significantly higher than those with regularly operating plasma filters, there was no significant difference between normal and inverse mode in the production of SC5b‐9. We conclude that the outer surface of the investigated conventional plasma filtration membranes is suitable for an inverse mode and does not lead to an excessive activation of the complement system upon dynamic blood contact. Thus, the inversion of the blood and the plasma compartments may be a possible way forward in the development of a high‐flow plasma separation filter.
Effectiveness of Combining Plasma Exchange and Continuous Hemodiafiltration in Patients With Postoperative Liver Failure
Authors: Yonekawa Chikara , Nakae Hajime , Tajimi Kimitaka , Asanuma Yoshihiro
Published: March 2005

Abstract:  Nine patients with postoperative liver failure were treated with plasma exchange (PE) or PE and continuous hemodiafiltration (CHDF), and various biochemical parameters were determined before and after treatment. Although citrate levels increased significantly after treatment compared with pretreatment levels in both the PE group and the PE + CHDF group (P < 0.0001 and P < 0.0001, respectively), the percentage of the increase in citrate levels was significantly higher in the PE group than in the PE + CHDF group (P = 0.0051). Total bilirubin (T‐Bil) levels were significantly lower after treatment in both the PE and PE + CHDF groups (P < 0.0001 and P = 0.0001, respectively). There were no significant differences in T‐Bil levels between the two groups (P = 0.5181). There were no significant differences in interleukin (IL)‐6 levels before and after treatment in both the PE and PE + CHDF groups (P = 0.1281  and P = 0.2273,  respectively).  IL‐18  levels  were  significantly  lower  after  treatment  in  both  the  PE  and PE + CHDF groups (P < 0.0001 and P = 0.0002, respectively), but there were no significant differences in the removal rate of IL‐18 in both the PE and PE + CHDF groups (P = 0.8749). These results indicate that combining PE and CHDF in a series–parallel circuit is an effective modality for suppressing the elevation of blood citrate levels. This finding may have important implications for the development of an effective treatment for patients with postoperative liver   failure.
Thyroid Disorders in Hemodialysis Patients in an Iodine‐deficient Community
Authors: Kutlay Sim , Atli Teslime , Koseogullari Osman , Nergizoglu Gokhan , Duman Neval , Gullu Sevim
Published: March 2005

Abstract:  There are various changes in the thyroid gland and its function in chronic renal failure (CRF). These changes include lower levels of circulating thyroid hormone, altered peripheral hormone metabolism, decreased binding to carrier proteins, possible reduction in tissue hormone content, and increased iodine storage in the thyroid gland. The decrease of excretion of urinary iodine in CRF increases serum inorganic iodine level and iodine content of the thyroid, which consequently enlarges the gland. This study is designed to investigate the prevalence of goiter and thyroid dysfunction in patients with end‐stage renal disease (ESRD) on hemodialysis (HD) in an iodine‐deficient community. Eighty‐seven (40 females and 47 males) HD patients and 169 (79 females and 90 males) healthy individuals as controls are included. Sex ratios for the patient and control groups are 0.85 and 0.88, respectively. Mean ages for the patient and control groups are 42.94 ± 11.88 and 40.20 ± 10.72 years, respectively. Examination of the thyroid gland using ultrasonography along with simultaneous measurement of blood levels of free‐T4 (FT4), free‐T3 (FT3), and thyrotropin (TSH) are made for every individual. The presence of goiter demonstrable by ultrasonography is found in 32.2% of the uremic patients and in 23.5% of the controls and its prevalence increases with age (P = 0.01). In 32 (36.8%) of the patients and 29 (17.1%) of the controls at least one thyroid nodule is found in ultrasonography. Between patients with or without a nodular goiter the authors could not observe any difference for duration of dialysis and serum levels of TSH, FT4, FT3, calcium, and albumin. In ESRD patients the prevalence of nodular goiter is higher for females (47.5% vs. 27.7%, P = 0.045) and increases with age (P = 0.04). Though incidence of hyperthyroidism is found to be similar for the two groups (1.14% in ESRD patients vs. 1.10% in controls), hypothyroidism is observed in 3.4% of ESRD patients but only 0.6% of controls. This high incidence of hypothyroidism and nodular goiter in ESRD patients shows that screening for thyroid dysfunction and goiter, using appropriate laboratory tests and ultrasonography, should be considered in evaluation of every ESRD patient.
Renal–Portal Shunt Ameliorates Renovascular Hypertension in Pigs
Authors: Katsenis Konstantinos , Vlahakos Demetrios V. , Antoniadis Pavlos , Kostopanagiotou Georgia , Antoniou Aris , Chatziioannou Achilles , Arapoglou Vassilis , Agroyannis Basil , Dimakakos Panagiotis
Published: March 2005

Abstract:  Background: Renovascular hypertension is the most common curable form of secondary hypertension. Renin angiotensin system activation depends on the balance between renin production by the kidney and renin degradation by the liver. Thus, we aimed to examine whether deviation of renin‐rich blood from the affected kidney into the portal circulation (portalization) can ameliorate renovascular hypertension. Methods: We selected a porcine model of unilateral renal artery stenosis because the pig's anatomy and physiology are comparable to those of humans and because pigs have already been found capable of developing chronic renovascular hypertension. Angiography and ultrasonography were deliberately used to evaluate renal artery stenosis and the renal–portal shunt. Histology was used to examine the effects of portalization on the kidney and liver after a period of two months. Results: As expected, following the creation of a left renal artery stenosis both renin activity and mean blood pressure measurements increased from 1.23 ± 0.06 ng/mL/h and 85.6 ± 0.5 mm Hg at baseline to 4.59 ± 0.02 ng/mL/h and 126 ± 1.76 mm Hg, respectively. After portalization renin activity returned to the normal range (1.59 ± 0.07 ng/mL/h) followed by a concomitant reduction of mean blood pressure to 91 ± 2 mm Hg. Moreover, a significant correlation was observed between changes in renin activity and blood pressure measurements during the two stages of the experiment. Both the kidney and liver remained macroscopically and microscopically intact at the end of the experiment. Conclusion: Portalization of the affected kidney can ameliorate renovascular hypertension and therefore, it might be of benefit in those individuals with fibromascular or atheromatous lesions in the renal artery or its branches not amenable to balloon angioplasty or surgical revascularization.
Design and Initial Testing of a Mock Human Circulatory Loop for Left Ventricular Assist Device Performance Testing
Authors: Liu Yingjie , Allaire Paul , Wood Houston , Olsen Don
Published: March 2005

Abstract: A mock circulatory loop, which simulates the human circulatory system, is needed to bench test the various versions of continuous flow (CF) left ventricular assist devices (LVADs). This article describes the design and initial testing of such a loop. The loop consists of: (1) pulsatile left and right cardiac simulators; (2) air/water tanks to model the venous and arterial compliances; (3) tygon tubes to model the venous, arterial, and other system flow resistances; and (4) a tuning clamp to model the variation in system resistance characteristics under different cardiac pressure/flow conditions. Several loop measurements were carried out without an LVAD to verify the cardiovascular modeling of a healthy person in sleep, rest, and physical activity, and in different pathological states, and compared to the data found in the literature to validate the loop performance prior to LVAD testing.
Religious and Ideological Dimensions of the Israeli Settlements Issue: Reframing the Narrative?
Authors: Susskind Lawrence , Levine Hillel , Aran Gideon , Kaniel Shlomo , Sheleg Yair , Halbertal Moshe
Published: March 2005

Whether or not it will be possible to relocate settlers from the “territories” depends not just on the willingness of the relevant Israeli officials to authorize evacuation of some or all of the West Bank and Gaza given the violence it may cause, but especially on the thinking and the changing attitudes of the settlers themselves. Only by understanding the views of the current settlers — their motivations, their beliefs, and the differences among them — will it be possible to formulate a sensible relocation strategy. That was the focus of the conference's first panel.
Political Dimensions of the Israeli Settlements Issue: Historic Opportunities and Challenges
Authors: Eiran Ehud , Kaufmann Chaim , Sher Gilead , Lustick Ian , Greenberg Jonathan
Published: March 2005

There is a danger inherent in devoting a panel to a discussion of the political aspects of the Israeli settlements issue: in attempting to discuss everything, we could have ended up talking about nothing because many practitioners and scholars view the settlements as primarily a political project. The multidisciplinary nature of this conference reflected our belief that the settlement issue is deeper and wider than “simply politics.” Yet, we were not free from the challenge of focusing a panel on the political aspects of the settlements in a way that makes a real contribution.
Legal Issues and Human Rights Dimensions of the Israeli Settlements Issue: Victims and Spoilers
Authors: Patton Bruce , Ignatieff Michael , Mandell Brian , Berger Eric , Matz David , Blank Yishai
Published: March 2005

The presenters on this panel discussed several important additional requirements for the successful implementation of a two‐state solution that involves significant relocation of settlers. These requirements include balancing rights among different groups, minimizing the impact of “spoilers,” and providing political compensation to settlers. Presenters also highlighted the relevance of elements of classic negotiation theory to this issue, including thinking creatively about substance and paying appropriate attention to process.
Compensation Schemes and Dispute Resolution Mechanisms: Beyond the Obvious
Authors: Sebenius James K. , Eiran Ehud , Feinberg Kenneth R. , Cernea Michael , McGovern Francis
Published: March 2005

Because compensation and dispute resolution lie at the core of most resettlement proposals, this panel had two main objectives: to get an accurate grasp of the current Israeli approach to these challenges and to glean insights from relevant experiences in other settings. Before reading our panelists’ presentations, one might be forgiven for reasonably thinking that “compensation equals cash” and “dispute resolution equals court.” As our panelists discussed, however, such a straightforward view is simply inadequate to the needs of the resettlement problem — a much richer view of compensation and dispute resolution is required.
International Dimensions: What Is the Role of Third Parties?
Authors: Lasensky Scott , Blum Gabriella , Shapiro Daniel B. , Raiffa Howard , Lewis Samuel , Malley Robert
Published: March 2005

In the Arab–Israeli arena, third parties have traditionally played a prominent role. External intervention has tended to peak when violence threatens international interests (e.g., the 1973 Arab–Israeli War), or when the parties are unable to sustain a negotiating process. Whether providing political and security assurances aimed at mitigating insecurity or offering economic inducements to underwrite peace accords, third parties have made a number of positive contributions toward managing the conflict.
Transcending Dualistic Thinking in Conflict Resolution
Authors: Collins Marla Del
Published: March 2005

Dualism, a doctrine espousing that everything in the universe is divided into polar opposites, is a defining characteristic of social discourse around the world. This article examines this phenomenon and suggests that dualism's centrality in language, thought, and action produces divisiveness and limits conflict resolution options. This essay proposes that more dynamical systems of interpretation originating from a broad range of disciplines including linguistics, the physical sciences, and Eastern religions can be useful in a variety of conflict resolution situations because they encourage more complex and creative thinking.
Teaching Law Students How to Feel: Using Negotiations Training to Increase Emotional Intelligence
Authors: Reilly Peter
Published: March 2005

This article suggests that negotiation courses using traditional lectures combined with role plays and simulated exercises can be used to train students in understanding emotion and increasing their emotional intelligence. The article defines emotion and emotional intelligence; describes and analyzes one simulated exercise that has proven to be particularly potent in the classroom for teaching both the theory and practice of emotional intelligence; sets forth the rudimentary components of a possible curriculum for emotions training; and concludes with reasons why law schools and other professional degree‐granting programs can and should make training in emotions a curriculum staple.
DATE SEED OIL: PHENOLIC, TOCOPHEROL AND STEROL PROFILES
Authors: BESBES SOUHAIL , BLECKER CHRISTOPHE , DEROANNE CLAUDE , BAHLOUL NEILA , LOGNAY GEORGES , DRIRA NOUR‐EDDINE , ATTIA HAMADI
Published: March 2005

Oils extracted from the seeds of two date palm (Phoenix dactylifera L.) cultivars, Deglet Nour and Allig, collected from Tunisia, were compared in terms of phenolic, tocopherol and sterol profiles. These minor components are not only very important for functional properties of oils (oxidation resistance, taste, aroma and color), but could also have many health benefits. Total phenols, considered as the principal source of oil oxidation resistance, ranged from 520.81 for Deglet Nour to 220.32 mg/kg for Allig. High performance liquid chromatography revealed eight identified peaks for which the major component was hydroxytyrosol (10.21%) for Deglet Nour and tyrosol for Allig (8.10%). Total sterol content was 3500 and 3000 mg/kg for Deglet Nour and Allig, respectively. The sterol marker, β‐sitosterol, accounted for 83.31 and 78.66% of total sterols in Deglet Nour and Allig seed oils, respectively. Alpha‐tocopherol was the predominant component in both date seed oils (24.97–38.85%).
A NEW METHOD FOR DETERMINATION OF TERT‐BUTYLHYDROQUINONE (TBHQ) IN RBD PALM OLEIN WITH FTIR SPECTROSCOPY
Authors: AMMAWATH W. , CHE MAN Y.B. , BAHARIN B.S. , ABDUL RAHMAN R.B.
Published: March 2005

Fourier transform infrared (FTIR) spectra of refined bleached and deodorized (RBD) palm olein samples between 3600 and 2800 cm−1 were used for quantitative determination of the content of tert‐butylhydroquinone (TBHQ). The method was based on sodium chloride (NaCl) windows with transmission path fixed at 50 µm at room temperature. Fifty stripped oil samples spiked with known amounts of TBHQ concentrations up to 300 mg/kg (ppm) were separated into two sets for calibration and validation models based on partial least squares (PLS) analyses. The accuracy of the method was comparable to that of the method established by the International Union of Pure and Applied Chemistry (IUPAC) with a coefficient of determination (R2) of 0.9961 and standard error of calibration of (SEC) 5.06. The model was validated, and the R2 of validation and standard error of prediction were 0.9951 and 6.49, respectively. The standard deviation of difference for repeatability for the method was comparable to that for the IUPAC method. The new FTIR method developed for determining TBHQ in palm olein was demonstrated to be efficient, accurate, rapid and required minimum solvent as only acetone was used for cleaning NaCl windows. The method is suitable for routine quality control analysis.
BIOCHEMICAL CHARACTERIZATION OF SOME TUNISIAN OLIVE OILS
Authors: DHIFI W. , HAMROUNI I. , AYACHI S. , CHAHED T. , SAÏDANI M. , MARZOUK B.
Published: March 2005

Four samples of Tunisian virgin olive oils of Chetoui, Chemlali, Chemchali and Oueslati varieties were analyzed for their chemical and fatty acid, total chlorophyll, total polyphenol and total aroma contents. The results showed that Chetoui was the most pigmented oil (4.45 ppm) and Oueslati oil contained the smallest amount of total chlorophylls (1.29 ppm). The Chetoui oil had the highest amount (94.37 ppm) of total polyphenols, while the Oueslati had the lowest amount (65.5 ppm). Furthermore, the Chemchali oil contained the highest level of total aroma (55.49 µg/mL of oil), followed by the Chemlali, Chetoui and Oueslati oils. The Chetoui oil was characterized by the highest level of oleic acid (70.9%) in contrast to the Chemlali, which had the lowest level of this fatty acid (58.6%). In addition, the highest level of palmitic acid characterizes the oil Chemlali (19.7%), whereas the Chetoui had the lowest (9.1%).
Pleiotropic Enhancement of Bacterial Pathogenesis Resulting from the Constitutive Activation of theListeria monocytogenesRegulatory Factor PrfA
Authors: Mueller Kimberly J. , Freitag Nancy E.
Published: March 2005

Listeria monocytogenesis a facultative intracellular bacterial pathogen that causes serious disease in immunocompromised individuals, pregnant women, and neonates. Bacterial virulence is mediated by the expression of specific gene products that facilitate entry into host cells and enable bacterial replication; the majority of these gene products are regulated by a transcriptional activator known as PrfA.L. monocytogenesstrains containingprfAE77K orprfAG155S mutations exhibit increased expression of virulence genes in broth culture and are hypervirulent in mice. To define the scope of the influences of theprfAE77K andprfAG155S mutations onL. monocytogenespathogenesis, multiple aspects of bacterial invasion and intracellular growth were examined. Enhanced bacterial invasion of host epithelial cells was dependent on the expression of a number of surface proteins previously associated with invasion, including InlA, InlB, and ActA. In addition to these surface proteins, increased production of thehly-encoded secreted hemolysin listeriolysin O (LLO) was also found to significantly enhance bacterial invasion into epithelial cell lines for bothprfAmutant strains. AlthoughprfAE77K andprfAG155S strains were similar in their invasive phenotypes, the infection of epithelial cells withprfAE77K strains resulted in host cell plasma membrane damage, whereasprfAG155S strains did not alter plasma membrane integrity. Bacterial infection of human epithelial cells, in which the production of LLO is not required for bacterial entry into the cytosol, indicated thatprfAE77K cytotoxic effects were mediated via LLO. BothprfAE77K andprfAG155S strains were more efficient than wild-type bacteria in gaining access to the host cell cytosol and in initiating the polymerization of host cell actin, and both were capable of mediating LLO-independent lysis of host cell vacuoles in cell lines for whichL. monocytogenesvacuole disruption normally requires LLO activity. These experiments illuminate the diverse facets ofL. monocytogenespathogenesis that are significantly enhanced by the constitutive activation of PrfA viaprfAmutations and underscore the critical role of this protein in promotingL. monocytogenesvirulence.
The
Actinobacillus actinomycetemcomitans
Autotransporter Adhesin Aae Exhibits Specificity for Buccal Epithelial Cells from Humans and Old World Primates
Authors: Fine Daniel H. , Velliyagounder Kabilan , Furgang David , Kaplan Jeffrey B.
Published: March 2005

Cells of the gram-negative periodontopathogen
Actinobacillus actinomycetemcomitans
express a surface-exposed, outer membrane autotransporter protein, designated Aae, which has been implicated in epithelial cell binding. We constructed a mutant strain of
A. actinomycetemcomitans
that contained a transposon insertion in the Aae structural gene (
aae
) and tested the mutant to determine its ability to bind to buccal epithelial cells (BECs) isolated from healthy volunteers. Significantly fewer mutant cells than wild-type cells bound to BECs. A broad-host-range plasmid that contained an intact
aae
gene driven by a heterologous
tac
promoter restored the ability of the mutant strain to bind to BECs at wild-type levels. This plasmid also conferred upon
Escherichia coli
the ability to express the Aae protein on its surface and to bind to human BECs. Aae-expressing
E. coli
also bound to BECs isolated from six Old World primates but not to BECs isolated from four New World primates or nine other nonprimate mammals, as well as to human gingival epithelial cells but not to human pharyngeal, palatal, tongue, bronchial, or cervical epithelial cells. Our findings indicate that Aae mediates binding of
A. actinomycetemcomitans
to BECs from humans and Old World primates and that this process may contribute to the host range specificity and tissue tropism exhibited by this bacterium.
Biofilm Formation by
Neisseria gonorrhoeae
Authors: Greiner L. L. , Edwards J. L. , Shao J. , Rabinak C. , Entz D. , Apicella M. A.
Published: March 2005

Studies were performed in continuous-flow chambers to determine whether
Neisseria gonorrhoeae
could form a biofilm. Under these growth conditions,
N. gonorrhoeae
formed a biofilm with or without the addition of 10 μM sodium nitrite to the perfusion medium. Microscopic analysis of a 4-day growth of
N. gonorrhoeae
strain 1291 revealed evidence of a biofilm with organisms embedded in matrix, which was interlaced with water channels.
N. gonorrhoeae
strains MS11 and FA1090 were found to also form biofilms under the same growth conditions. Cryofield emission scanning electron microscopy and transmission electron microscopy confirmed that organisms were embedded in a continuous matrix with membranous structures spanning the biofilm. These studies also demonstrated that
N. gonorrhoeae
has the capability to form a matrix in the presence and absence of CMP-
N
-acetylneuraminic acid (CMP-Neu5Ac). Studies with monoclonal antibody 6B4 and the lectins soy bean agglutinin and
Maackia amurensis
indicated that the predominate terminal sugars in the biofilm matrix formed a lactosamine when the biofilm was grown in the absence of CMP-Neu5Ac and sialyllactosamine in the presence of CMP-Neu5Ac.
N. gonorrhoeae
strain 1291 formed a biofilm on primary urethral epithelial cells and cervical cells in culture without loss of viability of the epithelial cell layer. Our studies demonstrated that
N. gonorrhoeae
can form biofilms in continuous-flow chambers and on living cells. Studies of these biofilms may have implications for understanding asymptomatic gonococcal infection.
Mast Cells Limit Systemic Bacterial Dissemination but Not Colitis in Response toCitrobacter rodentium
Authors: Wei Olivia L. , Hilliard Ashley , Kalman Daniel , Sherman Melanie
Published: March 2005

EnteropathogenicEscherichia coliand enterohemorrhagicE. colicause an inflammatory colitis in human patients characterized by neutrophil infiltration, proinflammatory cytokine expression, and crypt hyperplasia.Citrobacter rodentiumcauses a similar colitis in mice and serves as a model for enteropathogenicE. coliinfection in humans.C. rodentiuminduces systemic T-cell-dependent antibody production that facilitates clearance of the bacteria and protects the host from reinfection. The role of innate immune cells in infectious colitis, however, is less well understood. In this study, we have determined the role of mast cells in the inflammatory response and disease induced byC. rodentium. Mice deficient in mast cells exhibit more severe colonic histopathology and have a higher mortality rate following infection withC. rodentiumthan do wild-type animals. Despite unimpaired neutrophil recruitment and lymphocyte activation, mast cell-deficient mice have a disseminated infection evident in crucial organ systems that contributes to sepsis. Importantly, mast cells also have the capacity to directly killC. rodentium. Together, these results suggest that mast cells protect the host from systemic infection by reducing the bacterial load and preventing dissemination of the bacterium from the colon.
FatalPlasmodium falciparumMalaria Causes Specific Patterns of Splenic Architectural Disorganization
Authors: Urban Britta C. , Hien Tran T. , Day Nicholas P. , Phu Nguyen H. , Roberts Rachel , Pongponratn Emsri , Jones Margret , Mai Nguyen T. H. , Bethell Delia , Turner Gareth D. H. , Ferguson David , White Nicholas J. , Roberts David J.
Published: March 2005

The spleen is critical for host defense against pathogens, includingPlasmodium falciparum. It has a dual role, not only removing aged or antigenically altered erythrocytes from the blood but also as the major lymphoid organ for blood-borne or systemic infections. The human malaria parasiteP. falciparumreplicates within erythrocytes during asexual blood stages and causes repeated infections that can be associated with severe disease. In spite of the crucial role of the spleen in the innate and acquired immune response to malaria, there is little information on the pathology of the spleen in human malaria. We performed a histological and quantitative immunohistochemical study of spleen sections from Vietnamese adults dying from severe falciparum malaria and compared the findings with the findings for spleen sections from control patients and patients dying from systemic bacterial sepsis. Here we report that the white pulp in the spleens of patients dying from malaria showed a marked architectural disorganization. We observed a marked dissolution of the marginal zones with relative loss of B cells. Furthermore, we found strong HLA-DR expression on sinusoidal lining cells but downregulation on cordal macrophages.P. falciparuminfection results in alterations in splenic leukocytes, many of which are not seen in sepsis.
Pyrophosphatase of the RoundwormAscaris suumPlays an Essential Role in the Worm's Molting and Development
Authors: Islam M. Khyrul , Miyoshi Takeharu , Yamada Manabu , Tsuji Naotoshi
Published: March 2005

Previous studies indicated that inorganic pyrophosphatase ofAscaris suum(AsPPase) plays an important role in larval survival in the host. Here we describe a precise role for AsPPase in larval molting and development and also describe the potential role of recombinant AsPPase (rAsPPase) in protective immunity toA. suuminfection. Using reverse transcriptase PCR analysis, we found that disruption of AsPPase gene function by RNA interference resulted in suppression of AsPPase mRNA levels. RNA interference also caused inhibition of molting of third-stage larvae (31%) and suppression of native protein expression, as demonstrated by a 56% reduction in enzyme activity and quantified by immunoblot and immunofluorescence analyses, suggesting that AsPPase has a role in the molting process. The anatomic location of the AsPPase native enzyme in the hypodermis of larvae along with its elevated expression prior to and during the molting process supports such a role. Anti-rAsPPase immunoglobulin G (IgG) also resulted in 57% inhibition of molting ofA. suumlung-stage third-stage larvae to fourth-stage larvae in vitro with developmental arrest. Antigenic epitopes of AsPPase overlapped the enzyme active sites. Mice immunized with rAsPPase exhibited high antigen-specific IgG antibody responses and were protected (>70%) against a challengeA. suummigratory-phase infection. Splenic T cells from rAsPPase-immunized mice produced low levels of T helper 1-type cytokines (gamma interferon and interleukin-2) in vitro but exhibited an elevated interleukin-10 response. A significantly high level of IgG1 subclass antibodies was found in immunized mice. Our results establish that AsPPase has a critical role in the molting and development ofAscarisroundworms and suggest the potential of AsPPase for use as a candidate vaccine against ascariasis.
Melanization ofCryptococcus neoformansAffects Lung Inflammatory Responses during Cryptococcal Infection
Authors: Mednick Aron J. , Nosanchuk Joshua D. , Casadevall Arturo
Published: March 2005

The production of melanin pigments is associated with virulence for many microbes. Melanin is believed to contribute to microbial virulence by protecting microbial cells from oxidative attack during infection. However, there is also evidence from various systems that melanins have immunomodulatory properties, which conceivably could contribute to virulence by altering immune responses. To investigate the effect of melanin on the immune response, we compared the murine pulmonary responses to infection with melanized and nonmelanizedCryptococcus neoformanscells. Infection with melanized cells resulted in a greater fungal burden during the early stages of infection and was associated with higher levels of interleukin-4 and MCP-1 and greater numbers of infiltrating leukocytes. Infection with laccase-positive (melanotic)C. neoformanscells also elicited higher MCP-1 levels and more infiltrating leukocytes than did infection with laccase-negative cells. Melanization interfered with phagocytosis in vivo for encapsulatedC. neoformansbut not for nonencapsulated cells. The results provide strong evidence that cryptococcal melanization can influence the immune response to infection and suggest that immunomodulation is an additional mechanism by which the pigment contributes to virulence.
The
Legionella pneumophila tatB
Gene Facilitates Secretion of Phospholipase C, Growth under Iron-Limiting Conditions, and Intracellular Infection
Authors: Rossier Ombeline , Cianciotto Nicholas P.
Published: March 2005

Our previous mutational analysis of
Legionella pneumophila
demonstrated a role for type II protein (Lsp) secretion and iron acquisition in intracellular infection and virulence. In gram-negative bacteria, the twin-arginine translocation (Tat) pathway is involved in secretion of proteins, including components of respiratory complexes, across the inner membrane to the periplasm. To assess the significance of Tat for
L. pneumophila
,
tatB
mutants were characterized. The mutants exhibited normal growth in standard media but grew slowly under low-iron conditions. They were also impaired in the Nadi assay, indicating that the function of cytochrome
c
oxidase is influenced by
tatB
. Consistent with this observation, a subunit of the cytochrome
c
reductase was shown to be a Tat substrate. Supernatants of the
tatB
mutants showed a 30% reduction in phospholipase C activity while maintaining normal levels of other Lsp secreted activities. When tested for infection of U937 macrophages, the
tatB
mutants showed a 10-fold reduction in growth. Double mutants lacking
tatB
and Lsp secretion were even more defective, suggesting
tatB
has an intracellular role that is independent of Lsp.
tatB
mutants were also impaired 20-fold in
Hartmannella vermiformis
amoebae cultured in the presence of an iron chelator. All mutant phenotypes were complemented by reintroduction of an intact
tatB
. Thus,
L. pneumophila tatB
plays a role in the formation of a respiratory complex, growth under low-iron conditions, the secretion of a phospholipase C activity, and intracellular infection.
Avoidance of the Host Immune System through Phase Variation in
Mycoplasma pulmonis
Authors: Denison Amy M. , Clapper Brenda , Dybvig Kevin
Published: March 2005

Phase-variable lipoproteins are commonly found in
Mycoplasma
species.
Mycoplasma pulmonis
contains a family of extensively studied phase- and size-variable lipoproteins encoded by the
vsa
locus. The Vsa surface proteins vary at a high frequency, the in vivo significance of which has yet to be determined. We investigated the role of Vsa phase variation in respect to tissue tropism and avoidance of the immune system in the mouse host. Mycoplasmas were cultured 3, 14, and 21 days postinoculation from the nose, lung, trachea, liver, and spleen of experimentally infected C57BL/6 (wild-type), C57BL/6-RAG-1
−/−
(RAG
−/−
), and C57BL/6-inducible nitric oxide synthase (iNOS)
−/−
(iNOS
−/−
) mice. In wild-type and iNOS
−/−
mice, a large number of Vsa variants were seen by 21 days postinoculation. In contrast, little Vsa variation occurred in all tissues of RAG
−/−
mice. Analysis of isolates from 14 days postinoculation revealed less variation of the Vsa proteins in iNOS
−/−
mice than in the wild type. Western blot analysis of isolates from each strain of mouse demonstrated that Vsa phase variation occurred independently of size variation, indicating no obvious selection pressure for size variants. Additionally, these experiments provided no evidence that mycoplasmas producing particular Vsa proteins adhered only to specific tissues. The data strongly indicate that Vsa phase variation is a mechanism for avoidance of the immune system with no obvious contribution to tissue tropism.
Impact of the SpeB Protease on Binding of the Complement Regulatory Proteins Factor H and Factor H-Like Protein 1 byStreptococcus pyogenes
Authors: Wei Lin , Pandiripally Vinod , Gregory Eugene , Clymer Micaya , Cue David
Published: March 2005

Microbial pathogens often exploit human complement regulatory proteins such as factor H (FH) and factor H-like protein 1 (FHL-1) for immune evasion. Fba is an FH and FHL-1 binding protein expressed on the surface of the human pathogenic bacteriumStreptococcus pyogenes, a common agent of pharyngeal, skin, and soft-tissue infections. Fba has been shown to contribute to phagocytosis resistance, intracellular invasion, and virulence in mice. Here, we look at the role of Fba in recruitment of FH and FHL-1 by five serotype M1 isolates of streptococci. Inactivation offbagreatly inhibited binding of FH and FHL-1 by all isolates, indicating that Fba is a major FH and FHL-1 binding factor of serotype M1 streptococci. For three isolates, FH binding was significantly reduced in stationary-phase cultures and correlated with high levels of protease activity and SpeB (an extracellular cysteine protease) protein in culture supernatants. Analysis of aspeBmutant confirmed that SpeB accounts for the loss of Fba from the cell surface, suggesting that the protease may modulate FH and FHL-1 recruitment during infection. Comparisons offbaDNA sequences revealed that the FH and FHL-1 binding site in Fba is conserved among the M1 isolates. Although the ligand binding site is not strictly conserved in Fba from a serotype M49 isolate, the M49 Fba protein was found to bind both FH and FHL-1. Collectively, these data indicate that binding of FH and FHL-1 is a conserved function of Fba while modulation of Fba function by SpeB is variable.
Carbohydrate-Binding Specificity of the
Escherichia coli
Cytolethal Distending Toxin CdtA-II and CdtC-II Subunits
Authors: McSweeney Leslie A. , Dreyfus Lawrence A.
Published: March 2005

Intoxication by cytolethal distending toxin depends on assembly of CdtB, the active A component of this AB toxin, with the cell surface-binding (B) component, composed of the CdtA-CdtC heterodimer, to form the active holotoxin. Here we examine the cell surface binding properties of
Escherichia coli
-derived CdtA-II (CdtA-II
Ec
) and CdtC-II
Ec
and their capacity to provide a binding platform for CdtB-II
Ec
. Using a flow cytometry-based binding assay, we demonstrate that CdtB-II
Ec
binds to the HeLa cell surface in a CdtA-II
Ec
- and CdtC-II
Ec
-dependent manner and that CdtA-II
Ec
and CdtC-II
Ec
compete for the same structure on the HeLa cell surface. Preincubation of cells with glycoproteins (thyroglobulin and fetuin), but not simple sugars, blocks surface binding of CdtA-II
Ec
and CdtC-II
Ec
. Moreover, CdtA-II
Ec
and CdtC-II
Ec
bind immobilized fetuin and thyroglobulin as well as fucose and to a lesser degree
N
-acetylgalactoseamine and
N
-acetylglucoseamine. Removal of N- but not O-linked carbohydrates from fetuin and thyroglobulin prevents binding of CdtA-II
Ec
and CdtC-II
Ec
to these glycoproteins. In addition, removal of N- but not O-linked surface sugar attachments prevents CDT-II
Ec
intoxication. To characterize the cell surface ligand recognized by CdtA-II
Ec
and CdtC-II
Ec
, lectins having various carbohydrate specificities were used to block CDT activity and the cell surface binding of CdtA-II
Ec
and CdtC-II
Ec
. Pretreatment of cells with AAA, SNA-I, STA, UEA-I, GNA, and NPA partially or completely blocked CDT activity. AAA, EEA, and UEA-I lectins, all having specificity for fucose, blocked surface binding of CdtA-II
Ec
and CdtC-II
Ec
. Together, our data indicate that CdtA-II
Ec
and CdtC-II
Ec
bind an N-linked fucose-containing structure on HeLa cells.
Redundant Roles for Met Docking Site Tyrosines and the Gab1 Pleckstrin Homology Domain in InlB-Mediated Entry of
Listeria monocytogenes
Authors: Basar Tumay , Shen Yang , Ireton Keith
Published: March 2005

The bacterial pathogen
Listeria monocytogenes
causes food-borne illnesses leading to gastroenteritis, meningitis, or abortion.
Listeria
induces its internalization into some mammalian cells through interaction of the bacterial surface protein InlB with host Met receptor tyrosine kinase. Binding of InlB leads to phosphorylation of Met and the adapter Gab1 and to activation of host phosphoinositide (PI) 3-kinase. The mammalian ligand of Met, hepatocyte growth factor, promotes cell motility and morphogenesis in a manner dependent on phosphorylation of two docking site tyrosines at positions 1349 and 1356 in the receptor's cytoplasmic tail. Here we determined if these tyrosines were essential for
Listeria
entry. A derivative of the human cell line T47D stably expressing a truncated Met lacking most of its cytoplasmic domain was unable to support InlB-mediated signaling or entry. Surprisingly, cells expressing mutant Met containing phenylalanine substitutions in both tyrosines 1349 and 1356 (MetYF) allowed entry and InlB-induced Gab1 phosphorylation. However, in contrast to the situation in cells expressing wild-type Met, Gab1 phosphorylation in MetYF cells required PI 3-kinase activity. The Gab1 pleckstrin homology (PH) domain was constitutively associated with the plasma membrane of cells in a PI 3-kinase-dependent manner. Overexpression of the PH domain blocked entry of
Listeria
into cells expressing MetYF but not into cells expressing wild-type Met. Taken together, these results indicate that the docking site tyrosines are dispensable for internalization when membrane localization of Gab1 is constitutive. Distinct pathways of recruitment by phosphorylated tyrosines in Met and PH domain ligands in the membrane are redundant for bacterial entry.
Rhodococcus equi-Specific Cytotoxic T Lymphocytes in Immune Horses and Development in Asymptomatic Foals
Authors: Patton Kristin M. , McGuire Travis C. , Hines Melissa T. , Mealey Robert H. , Hines Stephen A.
Published: March 2005

Rhodococcus equiis an important cause of pneumonia in young horses; however, adult horses are immune due to their ability to mount protective recall responses. In this study, the hypothesis thatR. equi-specific cytotoxic T lymphocytes (CTL) are present in the lung of immune horses was tested. Bronchoalveolar lavage (BAL)-derived pulmonary T lymphocytes stimulated withR. equilysed infected alveolar macrophages and peripheral blood adherent cells (PBAC). As with CTL obtained from the blood, killing ofR. equi-infected targets by pulmonary effectors was not restricted by equine lymphocyte alloantigen-A (ELA-A; classical major histocompatibility complex class I), suggesting a novel or nonclassical method of antigen presentation. To determine whether or not CTL activity coincided with the age-associated susceptibility to rhodococcal pneumonia, CTL were evaluated in foals.R. equi-stimulated peripheral blood mononuclear cells (PBMC) from 3-week-old foals were unable to lyse either autologous perinatal or mismatched adult PBAC targets. The defect was not with the perinatal targets, as adult CTL effectors efficiently killed infected targets from 3-week-old foals. In contrast, significant CTL activity was present in three of five foals at 6 weeks of age, and significant specific lysis was induced by PBMC from all foals at 8 weeks of age. As with adults, lysis was ELA-A unrestricted. Two previously described monoclonal antibodies, BCD1b3 and CD1F2/1B12.1, were used to examine the expression of CD1, a nonclassical antigen-presenting molecule, on CTL targets. These antibodies cross-reacted with both foal and adult PBAC. However, neither antibody bound alveolar macrophages, suggesting that theR. equi-specific, major histocompatibility complex-unrestricted lysis is not restricted by a surface molecule identified by these antibodies.
Campylobacter jejuni-Induced Cytokine Responses in Avian Cells
Authors: Smith Chris K. , Kaiser Pete , Rothwell Lisa , Humphrey Tom , Barrow Paul A. , Jones Michael A.
Published: March 2005

Campylobacter jejuniis a major cause of human inflammatory enteritis. During the course of human disease numerous proinflammatory cytokines are produced. Little is known, however, about the cytokine responses produced during the interaction of this bacterium with the avian host.Campylobacterhas been considered a commensal of the avian host. Any differences in innate responses to this pathogen between the human and avian hosts should lead to a greater understanding of the disease process in humans. We have demonstrated expression of proinflammatory cytokines and chemokines in response toCampylobacterinfection in avian primary chick kidney cells and the avian macrophage cell line HD11. The data indicate thatCampylobactercan stimulate the avian host in a proinflammatory manner. The data strongly suggest that the lack of pathology in vivo is not due to an inability ofCampylobacterto stimulate a proinflammatory response from avian cells.