bluuebunny/crossref_metadata_2025_split huggingface dataset:
Primary immune response to keyhole limpet haemocyanin following trauma in relation to low plasma glutamine
Authors: BOELENS P G , FONK J C M , HOUDIJK A P J , SCHEPER R J , HAARMAN H J T H M , MEIJER S , VAN LEEUWEN P A M , VON BLOMBERG-VAN DER FLIER B M E 
Published: April 2004

SUMMARY
Severe trauma can lead to a compromised immune response, thereby increasing susceptibility to infections. Here we will study to what extent these early changes in the immune status upon trauma affect a primary immune response to keyhole limpet haemocyanin (KLH). Because glutamine is the preferred respiratory substrate for immune competent cells and known to be depleted after trauma, we studied the immune status and the primary sensitization in relation to the glutamine plasma concentration in a group of severe trauma patients [injury severity score (ISS) &gt;17]. Trauma patients (n = 31) were sensitized with KLH within 12 h after trauma; plasma glutamine concentrations and immune parameters were determined, after which KLH-specific immune responsiveness was evaluated on days 9 and 14. Low plasma glutamine concentrations were found after trauma. Significantly elevated numbers of granulocytes and CD14-positive leucocytes were found, whereas the HLA-DR expression on CD14-positive cells was significantly lower in trauma patients than in healthy controls. Trauma did not change the in vitro proliferative capacity of lymphocytes when cultured with glutamine; however, when lymphocytes were cultured without glutamine, trauma resulted in lower proliferation than healthy controls. Phytohaemagglutinin-(PHA)-induced interferon (IFN)-γ and interleukin (IL)-10 production was significantly lower after trauma, whereas IL-4 production was not affected. KLH sensitization following trauma resulted in poor skin test reactivity and low in vitro KLH-induced lymphocyte proliferation compared to controls. In contrast, the development of anti-KLH IgM, IgG, IgA, IgG1, IgG2, IgG3 and IgG4 production on days 9 and 14 following trauma was not different from that in healthy controls. Major trauma was associated with a reduced cell-mediated immune response, correlating with low plasma glutamine concentrations, while no effects of trauma were found on the development of a primary humoral immune response.
Cellular responses and cytokine production in post-treatment hookworm patients from an endemic area in Brazil
Authors: GEIGER S M , MASSARA C L , BETHONY J , SOBOSLAY P T , CORRÊA-OLIVEIRA R 
Published: April 2004

SUMMARYHuman hookworm infections are distributed widely in tropical areas and have a significant impact on host morbidity and human health. In the present study, we investigated the cellular responsiveness and cytokine production in peripheral blood mononuclear cells (PBMC) from Necator americanus-infected schoolchildren who had recently received chemotherapy, and compared them with non-infected endemic controls. Hookworm patients and treated, egg-negative individuals showed a lower cellular reactivity against phytohaemagglutinin (PHA) and hookworm antigen when compared with egg-negative endemic controls. The baseline production of proinflammatory tumour necrosis factor-α (TNF-α) in PBMC from infected patients and treated, egg-negative individuals was elevated. On the other hand, PHA- or hookworm antigen-induced interleukin (IL)-12 and interferon (IFN)-γ secretion was higher in endemic controls than in hookworm patients, who either continued egg-positive or were egg-negative after treatment. Also, PBMC from endemic controls secreted more IL-5 and IL-13 than the other patient groups. Opposite to that, the spontaneous as well as the antigen-driven IL-10 secretion was lower in endemic controls when compared with the other groups. In summary, patently hookworm-infected as well as egg-negative treated patients disclosed an elevated spontaneous cellular secretion of proinflammatory TNF-α, a prominent secretion of regulatory Th2-type IL-10 and an impaired production of IL-12, IFN-γ, IL-5 and IL-13.
Increased serum C3 levels in Crry transgenic mice partially abrogates its complement inhibitory effects
Authors: KANG H J , BAO L , XU Y , QUIGG R J , GICLAS P C , HOLERS V M 
Published: April 2004

SUMMARYComplement receptor 1-related gene/protein y (Crry) is a potent murine complement regulator that inhibits C3 convertases. Transgenic mice that overexpress soluble Crry (sCrry), directed systemically by the metallothionein-I promoter, have been used as an animal model for chronic blockade of complement activation. Recently we have found that alternative pathway (AP) activity in Crry transgenic mice was not inhibited as much as expected. To elucidate the mechanism of this effect, we evaluated the AP activities and levels of sCrry and AP complement components in transgenic and non-transgenic mice. In transgenic mice, expression of sCrry was induced by feeding zinc sulphate solution to 70·1 ± 42·7 µg/ml mean serum level. Its corresponding level of purified sCrry inhibited 49% of AP activity of normal mice serum; however, the actual AP activities in transgenic mice were not decreased when compared to non-transgenic mice (130·2 ± 9·0%versus 113·0 ± 35·4%). Expressed sCrry was functional, as immunoprecipitation and removal of sCrry from transgenic sera with rabbit anti-Crry polyclonal antibody resulted in enhanced AP activity, consistent with initial levels of sCrry. We then compared the changes to C3, factor B, factor H and factor D serum levels in transgenic and non-transgenic mice after induction of sCrry expression. Of these only C3 was increased after zinc feeding in transgenic mice compared to non-transgenic mice (142·8 ± 14·1%versus 121·4 ± 15·1%, P = 0·023). These results suggest that the inhibitory effect of chronic exposure to sCrry is compensated by concomitant alteration in C3 levels. This result also suggests the presence of a complement regulatory protein controls the level of serum C3, which has potential importance in the design and interpretation of studies involving chronic use of complement inhibitors.
Transfer factors as immunotherapy and supplement of chemotherapy in experimental pulmonary tuberculosis
Authors: FABRE R A , PÉREZ T M , AGUILAR L D , RANGEL M J , ESTRADA-GARCÌA I , HERNÁNDEZ-PANDO R , ESTRADA PARRA S 
Published: April 2004

SUMMARY
Problems of logistics, compliance and drug resistance point to an urgent need for immunotherapeutic strategies capable of shortening the current six month antibiotic regimens used to treat tuberculosis. One potential immunotherapeutic agent is transfer factors. Transfer factors (TF) are low molecular weight dialysable products from immune cells which transmit the ability to express delayed-type hypersensitivity (DTH) and cell mediated immunity from sensitized donors to nonimmune recipients. In this study we determined the efficiency of TF as immunotherapy to treat experimental tuberculosis. When BALB/c mice are infected via the trachea with Mycobacterium tuberculosis H37Rv there is an initial phase of partial resistance dominated by Th-1 type cytokines plus tumour necrosis factor-alpha (TNFα) and the inducible isoform of nitric oxide synthase (iNOS), followed by a phase of progressive disease characterized by increasing expression of IL-4, diminished expression of TNFα and iNOS, and low DTH. Animals in this late progressive phase of the disease (day 60) were treated with different doses of TF (one injection per week) obtained from spleen cells when the peak of immune protection in this animal model is reached (day 21), or with different doses of TF from peripheral leucocytes of PPD + healthy subjects. We show here that the treatment with murine or human TF restored the expression of Th-1 cytokines, TNFα and iNOS provoking inhibition of bacterial proliferation and significant increase of DTH and survival. This beneficial effect was dose dependent. Interestingly, murine TF in combination with conventional chemotherapy had a synergistic effect producing significant faster elimination of lung bacteria loads than chemotherapy alone.
IgG1 antimycobacterial antibodies can reverse the inhibitory effect of pentoxifylline on tumour necrosis factor alpha (TNF-α) secreted by mycobacterial antigen-stimulated adherent cells
Authors: THAKURDAS S M , HASAN Z , HUSSAIN R 
Published: April 2004

SUMMARYChronic inflammation associated with cachexia, weight loss, fever and arthralgia is the hallmark of advanced mycobacterial diseases. These symptoms are attributed to the chronic stimulation of tumour necrosis factor (TNF)-α. Mycobacterial components directly stimulate adherent cells to secrete TNF-α. We have shown recently that IgG1 antimycobacterial antibodies play a role in augmenting TNF-α in purified protein derivative (PPD)-stimulated adherent cells from non-BCG-vaccinated donors. We now show that IgG1 antibodies can also augment TNF-α expression in stimulated adherent cells obtained from BCG-vaccinated donors and this augmentation is not linked to interleukin (IL)-10 secretion. In addition IgG1 antimycobacterial antibodies can reverse the effect of TNF-α blockers such as pentoxifylline and thalidomide. These studies therefore have clinical implications for anti-inflammatory drug treatments which are used increasingly to alleviate symptoms associated with chronic inflammation.
Reproducibility of a novel model of murine asthma-like pulmonary inflammation
Authors: MCKINLEY L , KIM J , BOLGOS G L , SIDDIQUI J , REMICK D G 
Published: April 2004

SUMMARYSensitization to cockroach allergens (CRA) has been implicated as a major cause of asthma, especially among inner-city populations. Endotoxin from Gram-negative bacteria has also been investigated for its role in attenuating or exacerbating the asthmatic response. We have created a novel model utilizing house dust extract (HDE) containing high levels of both CRA and endotoxin to induce pulmonary inflammation (PI) and airway hyperresponsiveness (AHR). A potential drawback of this model is that the HDE is in limited supply and preparation of new HDE will not contain the exact components of the HDE used to define our model system. The present study involved testing HDEs collected from various homes for their ability to cause PI and AHR. Dust collected from five homes was extracted in phosphate buffered saline overnight. The levels of CRA and endotoxin in the supernatants varied from 7·1 to 49·5 mg/ml of CRA and 1·7–6 µg/ml of endotoxin in the HDEs. Following immunization and two pulmonary exposures to HDE all five HDEs induced AHR, PI and plasma IgE levels substantially higher than normal mice. This study shows that HDE containing high levels of cockroach allergens and endotoxin collected from different sources can induce an asthma-like response in our murine model.
Survival of Erwinia amylovora on pears and on fruit containers in cold storage and outdoors
Authors: Ceroni P. , Minardi P. , Babini V. , Traversa F. , Mazzucchi U. 
Published: April 2004

The survival of Erwinia amylovora during cold storage or outdoors may be a relevant factor in the spread of fireblight. The survival of E. amylovora was studied in cold storage on pear fruits, on container materials and on packaging paper, and outdoors on wood (oak and poplar) and on polyethylene. The samples were contaminated with a bacterial suspension of a mutant strain, washed, concentrated by centrifugation, and the final concentrates were used for plate counting. In cold storage, reisolation from the calyx was successful even after 101 days, whereas on pear surfaces, it was unsuccessful after just 1 day. On oak and poplar wood, reisolation was obtained up to 77 days in cold storage for both types of wood, but only up to 27 and 55 days, respectively, outdoors. Reisolation from packaging paper in cold storage was successful up to 14 days. Reisolation from polyethylene outdoors was unsuccessful after 24 h. Survival curves were calculated for each material. On the basis of a model of inoculum transmission, and using the survival curves, a phytosanitary risk period for the different types of materials was estimated.
Results of the systematic survey and control of Plum pox potyvirus in Slovenia
Authors: Viršček Marn M. , Mavrič I. , Benko‐Beloglavec A. , Knapič V. , Weilguny H. 
Published: April 2004

Sharka, caused by Plum pox potyvirus (PPV), was first observed in Slovenia in 1987. In the following years, the presence of PPV was confirmed by DAS‐ELISA in samples originating from orchards, individual trees and propagation material of stone fruits. In 1998, a systematic survey was initiated to prevent and control the spread of sharka and to establish pest‐free production sites. In the first 3 years of the systematic survey, the presence of PPV was also monitored outside production sites for propagating material and their buffer zones, in order to establish the current incidence of sharka in Slovenia. The results showed an overall presence of PPV infection in Slovenia. Since 2000, the survey has focused mainly on nurseries, mother trees and stool‐beds. In spite of strict official supervision and eradication measures, the incidence of sharka in propagating material production sites increased until 2002. A significant decrease in the number of PPV‐infected mother trees, stool‐beds, nurseries and buffer zones was finally obtained in 2002, as a consequence of the vast effort dedicated to containment of sharka in Slovenia.
Traitement phytosanitaire du bois par chauffage à cœur
Authors: Aléon D. 
Published: April 2004

Suite à l’adoption de la NIMP no. 15 et en particulier l’exigence relative au traitement à la chaleur des emballages en bois, une étude a été menée par le Centre Technique du Bois et de l’Ameublement. Cette étude vise à disposer d’abaques de montée en température du bois permettant de garantir un traitement à cœur pendant 30 min à 56 °C en mesurant la température de l’ambiance et non celle à cœur du bois. Un tel système de mesure de température, outre sa facilité de mise en oeuvre, présente de meillures garanties que l’ensemble du bois dans la chambre a subi un traitement adéquat.
Sphingolipid‐free Leishmania are defective in membrane trafficking, differentiation and infectivity
Authors: Denny Paul W. , Goulding David , Ferguson Michael A. J. , Smith Deborah F. 
Published: April 2004

SummarySphingolipids are structural components of the eukaryotic plasma membrane that are involved, together with cholesterol, in the formation of lipid microdomains (rafts). Additionally, sphingolipid metabolites have been shown to modulate a wide variety of cellular events, including differentiation and apoptosis. To investigate the role of de novo sphingolipid biosynthesis in Leishmania, we have focused on serine palmitoyltransferase (SPT), which catalyses the first, rate‐limiting step in the synthetic pathway. Genetic ablation of one SPT subunit, LmLCB2, yields viable null parasites that can no longer synthesize ceramide and sphingolipids de novo. Unexpectedly, LmLCB2 expression (and sphingolipid biosynthesis) is stage regulated in Leishmania, being undetectable in intramacrophage parasites. As expected from this observation, the LmLCB2 null mutants maintain infectivity in vivo. However, they are compromised in their ability to form infective extracellular parasites, correlating with a defect in association of the virulence factor, leishmanolysin or GP63, with lipid rafts during exocytosis and an observed relocalization of a second virulence factor, lipophosphogycan, during differentiation. Thus, de novo sphingolipid biosynthesis is critical for membrane trafficking events in extracellular Leishmania but has at best a minor role in intracellular pathogenesis.
Inversion within the haloalkaliphilic virus φCh1 DNA results in differential expression of structural proteins
Authors: Rössler N. , Klein R. , Scholz H. , Witte A. 
Published: April 2004

SummaryThe sequence of φCh1 contains an open reading frame (int1) in the central part of its genome that belongs to the λ integrase family of site‐specific recombinases. Sequence similarities to known integrases include the highly conserved tetrad R‐H‐R‐Y. The flanking sequences of int1 contain several direct repeats of 30 bp in length (IR‐L and IR‐R), which are orientated in an inverted direction. Here, we show that a recombination active region exists in the genome of φCh1: the number of those repeats, non‐homologous regions within the repeat clusters IR‐L and IR‐R and the orientation of the int1 gene vary in a given virus population. Within this study, we identified circular intermediates, composed of the int1 gene and the inwards orientated repeat regions IR‐L and IR‐R, which could be involved in the recombination process itself. IR‐L and IR‐R are embedded within ORF34 and ORF36 respectively. As a consequence of the inversion within this region of φCh1, the C‐terminal parts of the proteins encoded by ORF34 and 36 are exchanged. Both proteins, expressed in Escherichia coli, interact with specific antisera against whole virus particles, indicating that they could be parts of φCh1 virions. Expression of the protein(s) in Natrialba magadii could be detected 98 h after inoculation, which is similar to other structural proteins of φCh1. Taken together, the data show that the genome of φCh1 contains an invertible region that codes for a recombinase and structural proteins. Inversion of this segment results in a variation of these structural proteins.
Unequal access of chromosomal regions to each other in Salmonella: probing chromosome structure with phage λ integrase‐mediated long‐range rearrangements
Authors: Garcia‐Russell Nathalie , Harmon Timothy G. , Le Tien Q. , Amaladas Nelusha H. , Mathewson Richard D. , Segall Anca M. 
Published: April 2004

SummaryWe have investigated the fluidity of the Salmonella chromosome architecture using the phage lambda site‐specific recombination system as a probe. We determined how chromosome position affects the extent of integrase‐mediated recombination between pairs of inversely oriented att sites at various loci. We also investigated the accessibility of each chromosomal att site to an extrachromosomal partner carried on a low‐copy plasmid. Recombination events were assayed by semi‐quantitative polymerase chain reaction of the attP product. The extent of recombination between the chromosome and the plasmid was generally higher than intrachromosomal recombination except for two loci, araA::attL and galT::attL, which gave no detectable recombination with any other locus. Based on 20 intervals, we found that chromosomal locations are not equally accessible to each other. Although multiple factors probably affect accessibility, the most important is the specific combination of the end‐points used. Neither the size of the intervals nor the accessibility of individual end‐points to extrachromosomal sequences is as important. These results suggest that the chromosome is not completely fluid but rather organized in some way, with barriers that limit the movement of DNA within the cell. The nature of the barriers involved in chromosomal organization remains to be determined.
Dispensable PDZ domain of Escherichia coli YaeL essential protease
Authors: Bohn Chantal , Collier Justine , Bouloc Philippe 
Published: April 2004

SummaryIn Escherichia coli, adaptation to extra‐cytoplasmic stress relies on σE activation to induce a rescue pathway. Under non‐stressed conditions, σE is sequestered by the inner membrane protein RseA. Extra‐cytoplasmic stress activates DegS‐dependent cleavage of RseA, rendering RseA sensitive to further degradation by the YaeL protease. YaeL contains two motifs characteristic of a family of metallo‐proteases, as well as a periplasmic PDZ domain. We report results of mutational analyses of the YaeL domains. Surprisingly, expression in a strain depleted for wild‐type YaeL or YaeL variants having a 40 amino acid deletion of the PDZ domain or amino acid substitutions of conserved amino acids of the YaeL PDZ domain did not affect cell viability. The proteolytic activity against RseA of these YaeL variants became independent of DegS. These observations suggest that the YaeL PDZ domain exerts a negative control on YaeL activity. Rather than being involved in substrate recognition, the PDZ domain of YaeL is likely to act as an inhibitor of proteolytic activity.
Expression of the chitobiose operon of Escherichia coli is regulated by three transcription factors: NagC, ChbR and CAP
Authors: Plumbridge Jacqueline , Pellegrini Olivier 
Published: April 2004

SummaryThe chitobiose operon, chbBCARFG, encodes genes for the transport and degradation of the N‐acetylglucosamine disaccharide, chitobiose. Chitobiose is transported by the phosphotransferase system (PTS) producing chitobiose‐6P which is hydrolysed to GlcNAc‐6P by the chbF gene product and then further degraded by the nagBA gene products. Expression of the chb operon is repressed by NagC, which regulates genes involved in amino sugar metabolism. The inducer for NagC is GlcNAc‐6P. NagC binds to two sites separated by 115 bp and the transcription start point of the chb operon lies within the downstream NagC operator. In addition the chb operon encodes its own specific regulator, ChbR, an AraC‐type dual repressor–activator, which binds to two direct repeats of 19 bp located between the two NagC sites. ChbR is necessary for transcription activation in the presence of chitobiose in vivo. Induction of the operon also requires CAP, which binds to a site upstream of the ChbR repeats. In the absence of chitobiose both NagC and ChbR act as repressors. Together these three factors cooperate in switching chb expression from the repressed to the activated state. The need for two specific inducing signals, one for ChbR to activate the expression of the operon and a second for NagC to relieve its repression, ensure that the chb operon is only induced when there is sufficient flux through the combined chb‐nag metabolic pathway to activate expression of both the chb and nag operons.