bluuebunny/crossref_metadata_2025 huggingface dataset:
Local Definition of Ty1 Target Preference by Long Terminal Repeats and Clustered tRNA Genes
Authors: Bachman Nurjana , Eby Yolanda , Boeke Jef D.
Published: June 2004

LTR-containing retrotransposons reverse transcribe their RNA genomes, and the resulting cDNAs are integrated into the genome by the element-encoded integrase protein. The yeast LTR retrotransposon Ty1 preferentially integrates into a target window upstream of tDNAs (tRNA genes) in the yeast genome. We investigated the nature of these insertions and the target window on a genomic scale by analyzing several hundred de novo insertions upstream of tDNAs in two different multicopy gene families. The pattern of insertion upstream of tDNAs was nonrandom and periodic, with peaks separated by ∼80 bp. Insertions were not distributed equally throughout the genome, as certain tDNAs within a given family received higher frequencies of upstream Ty1 insertions than others. We showed that the presence and relative position of additional tDNAs and LTRs surrounding the target tDNA dramatically influenced the frequency of insertion events upstream of that target.
A Transcript Finishing Initiative for Closing Gaps in the Human Transcriptome
Authors:   The Ludwig–FAPESP Transcript Finishing Initiative, Sogayar Mari Cleide , Camargo Anamaria A.
Published: June 2004

We report the results of a transcript finishing initiative, undertaken for the purpose of identifying and characterizing novel human transcripts, in which RT-PCR was used to bridge gaps between paired EST clusters, mapped against the genomic sequence. Each pair of EST clusters selected for experimental validation was designated a transcript finishing unit (TFU). A total of 489 TFUs were selected for validation, and an overall efficiency of 43.1% was achieved. We generated a total of 59,975 bp of transcribed sequences organized into 432 exons, contributing to the definition of the structure of 211 human transcripts. The structure of several transcripts reported here was confirmed during the course of this project, through the generation of their corresponding full-length cDNA sequences. Nevertheless, for 21% of the validated TFUs, a full-length cDNA sequence is not yet available in public databases, and the structure of 69.2% of these TFUs was not correctly predicted by computer programs. The TF strategy provides a significant contribution to the definition of the complete catalog of human genes and transcripts, because it appears to be particularly useful for identification of low abundance transcripts expressed in a restricted set of tissues as well as for the delineation of gene boundaries and alternatively spliced isoforms.
Reconstruction and Validation of Saccharomyces cerevisiae iND750, a Fully Compartmentalized Genome-Scale Metabolic Model
Authors: Duarte Natalie C. , Herrgård Markus J. , Palsson Bernhard Ø.
Published: June 2004

A fully compartmentalized genome-scale metabolic model of Saccharomyces cerevisiae that accounts for 750 genes and their associated transcripts, proteins, and reactions has been reconstructed and validated. All of the 1149 reactions included in this in silico model are both elementally and charge balanced and have been assigned to one of eight cellular locations (extracellular space, cytosol, mitochondrion, peroxisome, nucleus, endoplasmic reticulum, Golgi apparatus, or vacuole). When in silico predictions of 4154 growth phenotypes were compared to two published large-scale gene deletion studies, an 83% agreement was found between iND750's predictions and the experimental studies. Analysis of the failure modes showed that false predictions were primarily caused by iND750's limited inclusion of cellular processes outside of metabolism. This study systematically identified inconsistencies in our knowledge of yeast metabolism that require specific further experimental investigation.
An Efficient Method to Generate Chromosomal Rearrangements by Targeted DNA Double-Strand Breaks inDrosophila melanogaster
Authors: Egli Dieter , Hafen Ernst , Schaffner Walter
Published: June 2004

Homologous recombination (HR) is an indispensable tool to modify the genome of yeast and mammals. More recently HR is also being used for gene targeting inDrosophila. Here we show that HR can be used efficiently to engineer chromosomal rearrangements such as pericentric and paracentric inversions and translocations inDrosophila. Two chromosomal double-strand breaks (DSBs), introduced by the rare-cutting I-SceI endonuclease on two different mobile elements sharing homologous sequences, are sufficient to promote rearrangements at a frequency of 1% to 4%. Such rearrangements, once generated by HR, can be reverted by Cre recombinase. However, Cre-mediated recombination efficiency drops with increasing distance between recombination sites, unlike HR. We therefore speculate that physical constraints on chromosomal movement are modulated during DSB repair, to facilitate the homology search throughout the genome.
International Conference on Digital Libraries 2004 Conference
Authors: Kar Debal C. , Seadle Michael
Published: June 2004

The conference co‐ordinator and an invited speaker of the International Conference on Digital Libraries (ICDL) which took place in New Delhi, India, February 2004 provide an overview of the conference – one of a growing series of digital library conferences that bring together computer scientists and librarians. The objectives of this conference were to bridge the knowledge gaps between developing and developed countries; initiate capacity building activities in digital libraries; evolve a road map for the digitization of archives, manuscripts and libraries; provide a forum for facilitating interaction among participants; and formulate recommendations on digitization technologies and policies. Outlines the themes and topics covered and provides the main points of the inaugural address to the conference by the President of India as well as the three keynote addresses.
Computers in Libraries Conference, Washington, DC
Authors: Hennessey Christina
Published: June 2004

Provides an overview of the 19th annual Computers in Libraries conference held in Washington, DC, in March 2004. The main theme of the conference was to focus on “all aspects of library and information delivery technology”. States that the popular topics of discussion were search engine updates, federated searching, blogging, RSS, social networking, institutional repositories, and portals. Notes that the conference was not for the technology beginner or librarians uncomfortable with technology. The conference had over 2,400 attendees from 14 countries and almost every US state, and 50 different exhibitors. It featured over 100 sessions, three keynotes, several pre‐conference and post‐conference workshops, and many 15‐minute “cybertour” sessions in the exhibition area.
SURA/ViDe Digital Video Workshop: A Summary
Authors: Lessick Susan
Published: June 2004

Gives an overview of the SURA/ViDe 6th Annual Digital Video Workshop held at Indiana University‐Purdue University Indianapolis in March 2004. The SURA Video Development Initiative (SURA/ ViDe) was established in 1998 to promote and develop functional, standards‐based and scalable video systems for use in the higher education environment by leveraging collective resources and expertise towards addressing challenges to deployment. Outlines the four main tracks of the programme.
ICT in Distance Education in Ghana
Authors: Martey Alfred
Published: June 2004

This article describes the ICT scene in Ghana from 1996 to 2004. The emphasis is on the benefits that distance learners in Ghana will derive from an ICT‐enhanced distance education. The article also draws attention to the efforts made by various governments of Ghana and some agencies to solve the major problems facing ICT‐driven distance education in Ghana. The attention of Distance education providers are made aware of the minor but disruptive operational hindrances to the use of ICT. Some suggestions are made as to how academic libraries in Ghana can assist distance learners now.
A Global Experiment in Adaptive Tutorial Computer‐Based Learning in Mathematics for Young Children
Authors: Bork Alfred , Hui Philip
Published: June 2004

Education is essential for economic progress, happiness, and reducing violence. This paper discusses global effectiveness of distance computer‐based modules, both learning and cost. Frequent interaction will be in each student’s language, computer to student and student to computer, with either keyboard or speech input. The units developed will be highly adaptive for students of any ethnic group, gender, or economic background. The goal is mastery for almost all students, in distance learning and schools. Current technology is adequate. Mathematics will be used as an example.
Freud in Cambridge
Authors: Forrester John
Published: June 2004

The lecture sketches a previously unacknowledged source of intense interest in psychoanalysis in Cambridge in the 1920s, amongst non‐medical scientists, some but not all of whom were loosely associated with Bloomsbury. Amongst them were Lionel Penrose (later founder of human genetics) and Frank Ramsey (mathematician and philosopher), whose pilgrimages to Vienna are followed. The lecture reflects on the implications of this episode for the place of psychoanalysis in the university, both then and now.
Augmentation of skin response by exposure to a combination of allergens and irritants – a review
Authors: Pedersen Line Kynemund , Johansen Jeanne Duus , Held Elisabeth , Agner Tove
Published: June 2004

Clinical experimental studies on contact dermatitis (CD) often evaluate the effect of one allergen or one irritant at a time. In real life, the skin is often exposed to more allergens, more irritants or allergens and irritants in combination. This combined exposure may potentially influence irritant effects as well as allergenicity of the substances. Mechanisms for a changed response can be immunological effects or enhanced penetration. Knowledge about the influence on skin reaction of combined exposures may influence skin reactivity and is important for prevention of CD. For allergens, threshold values may be influenced by the presence of other allergens or irritants, and prevention of CD by regulation of threshold values may not be sufficient if this is not taken into account.
Kinetics of spleen and Peyer's patch lymphocyte populations during gut parasite clearing in Cryptosporidium parvum infected suckling mice
Authors: Mariotte D. , Comby E. , Brasseur P. , Ballet J. J.
Published: June 2004

Data from experimental and human cryptosporidiosis have established a major role of specific immunity in the control of Cryptosporidium parvum infection. In this work, alterations in spleen and Peyer's patch (Pp) lymphocytes were investigated in the course of a spontaneously resolutive gut cryptosporidiosis in four‐day‐old suckling NMRI mice infected with either 4 × 105 or 30 viable oocysts. Oocysts from entire small intestines, and spleen and Pp lymphocytes were examined using flow cytometry from day 7 to day 27 post‐infection. Compared to uninfected animals, a 3–5 fold increase in the numbers of spleen TCR αβ+, CD4+, CD8+, TCR γδ+ and CD45R/B220+ lymphocytes was observed on day 17 post‐infection in heavily infected animals. In Pp, more than ten‐fold increases were observed, except for TCR γδ+ lymphocytes. At termination of infection, i.e. on days 21–23 after ingestion of 4 × 105 oocysts, T and B lymphocytes decreased rapidly in both organs, and remained lower than in uninfected animals on days 19–23 post‐infection. In mice infected with 30 oocysts, similar alterations were observed in Pp, but not in spleen. Data suggest that in normally developing mice, clearance of gut C. parvum infection is associated with an initial increase in systemic and local lymphocyte numbers, followed by their decrease to below control levels during the recovery phase.
Early treatment during a primary malaria infection modifies the development of cross immunity
Authors: Legorreta‐Herrera M. , Ventura‐Ayala M. L. , Licona‐Chávez R. N. , Soto‐Cruz I. , Hernández‐Clemente F. F.
Published: June 2004

We have used a murine model to study the kinetics of cross‐protection when a primary infection is halted at different times. We analysed how parasitaemia is modified during a second infection with the homologous parasite, a heterologous parasite, or a mixture of the two. In addition, possible mechanisms involved in cross‐protection were analysed. Results show that treatment with pyrimethamine on day 5 during a primary infection with P. chabaudi AS (non‐lethal), prevents the generation of cross‐protection to a new challenge with lethal P. yoelii 17XL. In contrast, when treatment is on day 7, mice survive a P. yoelii infection. Differences between both groups suggest that in order for ‘preimmune’ mice to survive a lethal challenge, a predominantly TH2‐type response is required, with a higher mRNA expression level of IL‐4 and IL‐10, and a lower mRNA expression of IFN‐γ. This work shows that an early treatment of a malaria infection produced by a non‐lethal parasite drives the immune response towards a loss of cross‐protection to further infections, in particular with more virulent parasites. This finding should be taken into account for the development of effective malaria vaccines.
CTLA‐4 regulates the murine immune response to Trypanosoma cruzi infection
Authors: Graefe S. E. B. , Jacobs T. , Wächter U. , Bröker B. M. , Fleischer B.
Published: June 2004

Infection with Trypanosoma cruzi causes a profound suppression of T cell responsiveness to polyclonal or antigenic stimuli. In this study, we quantified expression of the negative T cell regulatory molecule CTLA‐4 in T. cruzi infected mice and analysed its influence on the immune suppression. Levels of splenic CTLA‐4 expression were highest around day 10 after infection, reaching 5% in resistant B6D2F1 mice, but exceeding 10% of CD4+ T cells in C57BL/6 mice that were susceptible to mortal disease. The proliferative response of explanted splenocytes to CD3‐mediated stimulation was strongly suppressed in both the susceptible and the resistant strains. Blockade of CTLA‐4 in vitro with a monoclonal antibody affected neither proliferative response nor cytokine production (IFN‐γ, IL‐4 and IL‐2) by splenic T cells from infected C57BL/6 mice. Treatment of mice with anti‐CTLA‐4 antibody on the day of infection decreased IFN‐γ production and reduced mortality by about 50%. We conclude that high CTLA‐4 expression is a hallmark of severe disease in murine T. cruzi infection, and that CTLA‐4 has a regulative influence at the early stages during priming of the immune reaction to the parasite, augmenting a strong Th1‐biased response.
Are the cellular immune responses of children and adults with Schistosoma mansoni infection intrinsically different? Cytokines produced ex vivo in response to antigens and mitogens
Authors: Scott J. T. , Vereecken K. , Diakhaté M. M. , Vanagt T. , Sambou V. , Diop M. , Ly A. , Vercruysse J. , Gryseels B. , Kestens L.
Published: June 2004

In recently exposed communities, intensity of schistosomiasis infection increases as children age and then drops again in adulthood, indicating that host maturity is an important aspect of resistance to schistosomiasis. We investigated whether the cellular immune response to the parasite was correlated with age in subjects with similar daily patterns of exposure, current intensities of infection and number of years of exposure.

The cellular immune response of subjects with either ‘low’ (under 200 eggs per gram (EPG)) or ‘high’ (over 400 EPG) intensities of infection was investigated, in a recently established focus where subjects had similar histories of exposure and number of years of experience with Schistosoma mansoni. Subject's whole blood was cultured with adult worm antigen (AWA), a mixture of phytohaemagglutinin (PHA) and lipopolysaccharide (LPS), or left unstimulated, and culture supernatants were tested for IL‐4, IL‐5, IL‐10 and IFN‐γ.

Children and adults tended to respond differently to schistosome antigen. The most statistically significant illustration of this was the negative correlation between age and IL‐5 produced by samples from people with low intensities of infection cultured with AWA (P < 0·003, P < 0·05 after Bonferroni correction). IL‐10 produced by samples cultured with PHA and LPS was also notably lower in children than in adults, although not formally significant after Bonferoni correction.

This indicates that it is possible for age, independently of intensity of infection or experience with the parasite, to influence the immune response to schistosomiasis.
Validation of the protective Ostertagia ostertagi ES‐thiol antigens with different adjuvantia
Authors: Geldhof P. , Vercauteren I. , Vercruysse J. , Knox D. P. , Van Den Broeck W. , Claerebout E.
Published: June 2004

Intramuscular immunization of calves with an excretory–secretory antigen fraction enriched for cysteine proteinase activity (ES‐thiol) and QuilA as adjuvant induces a protective immune response against the abomasal nematode Ostertagia ostertagi. The objectives of the present study were to confirm the protective capacity of ES‐thiol in combination with QuilA, to test Al(OH)3 as adjuvant for vaccination against O. ostertagi and to look for correlations between protection and immunological effector responses. Calves(seven animals/group) were vaccinated three times intramuscularly with 100 µg antigen and/or adjuvant (ES‐thiol with QuilA, ES‐thiol with Al(OH)3, QuilA alone and Al(OH)3 alone) and subsequently challenged with a trickled oral infection of 25 000 infective larvae in total over 25 days. Faecal egg counts in the ES‐thiol QuilA group were reduced by 56% during the two‐month period of the trial compared to the QuilA control group (P < 0·002). Calves immunized with ES‐thiol QuilA had significantly smaller adult worms (P < 0·002) and less eggs/female worm (P < 0·05) compared to the QuilA control group. No differences in egg output, worm counts or parameters of worm fitness were observed in the ES‐thiol Al(OH)3 group compared to the Al(OH)3 control group. Although the protective immune mechanism against O. ostertagi remains unknown, protection in the ES‐thiol QuilA group was associated with high levels of parasite‐specific antibodies in the abomasal mucosa.
Echinococcus granulosus‐specific T‐cell lines derived from patients at various clinical stages of cystic echinococcosis
Authors: Riganò R. , Buttari B. , De Falco E. , Profumo E. , Ortona E. , Margutti P. , Scottà C. , Teggi A. , Siracusano A.
Published: June 2004

To investigate the role of T lymphocytes in the immune response to Echinococcus granulosus, using sheep hydatid fluid (SHF) and antigen B (AgB), we generated T‐cell lines from patients with active, transitional and inactive hydatid cysts. We established 16 T‐cell lines, eight specific to SHF and eight specific to AgB. At surface phenotyping 88–98% of cells displayed the helper/inducer CD4 antigen. In all patients, at all clinical stages of hydatid cyst disease, T‐cell stimulation with SHF and AgB invariably amplified a large number of almost identical Vβ subfamily fragments. Irrespective of antigen‐specificity, the two cell lines from the patient with an inactive cyst had a Th1 profile, because they exclusively expressed and produced IFN‐γ. Conversely, the T‐cell lines derived from the seven patients with active and transitional hydatid cysts had mixed Th1/Th2 and Th0 clones. The functional characteristics of the 16 T‐cell lines differed markedly in the various clinical stages of cystic echinococcosis, thus providing new in vitro evidence that Th1 lymphocytes contribute decisively to the inactive stage of hydatid disease, Th2 lymphocytes in the active and transitional stages. The parasite‐specific T‐cell lines, especially the two Th1 lines from the patient with an inactive cyst, may help identify Th1 protective epitopes on SHF and AgB.
Ov‐ASP‐1, the Onchocerca volvulus homologue of the activation associated secreted protein family is immunostimulatory and can induce protective anti‐larval immunity
Authors: MacDonald A. J. , Tawe W. , Leon O. , Cao L. , Liu J. , Oksov Y. , Abraham D. , Lustigman S.
Published: June 2004

Vaccination of mice with a recombinant protein, Ov‐ASP‐1, the Onchocerca volvulus homologue of the activation associated secreted gene family stimulated very high titres of both IgG1 and IgG2a without adjuvant. rOv‐ASP‐1 was also immuno‐reactive with IgG isotypes from both O. volvulus‐infected (INF) and putatively immune (PI) humans, with higher IgG4 in the former group. The protein also stimulated IFN‐γ secretion by PBMC from INF and PI and IL‐5 only in INF. Using a mouse diffusion chamber model, vaccination with rOv‐ASP‐1 resulted in partial but significant protection against challenge with infective third‐stage larvae (L3) but only when formulated with Freund's complete adjuvant (FCA) or alum. Protection was Th1‐dependent (highly elevated IgG2a) with FCA and contingent on a strongly Th2‐skewed (IgG1) response with alum. IgE responses to rOv‐ASP‐1 with or without adjuvant were weak or absent. When immunization using rOv‐ASP‐1 in adjuvant failed to induce adequate Th1 (FCA) or Th2 (alum) responses, protection efficacy was compromised. The recombinant protein appears to stimulate a mixed Th1/Th2 response but the outcome in terms of protective immunity is the result of a subtle interplay of its intrinsic and adjuvant‐augmented properties. Ov‐ASP‐1 is potentially secreted based on its localization in the secretory granules of L3.
Venezuela, April 2002: Coup or Popular Rebellion? The Myth of a United Venezuela
Authors: Cannon Barry
Published: June 2004

This article assesses the merits of opposing National Assembly reports into the coup against President Chávez of Venezuela in April 2002. Looking at the historical context and the content of the reports, it argues that the two opposing accounts reflect a class division that has always existed in Venezuela but has been officially denied. It concludes that a possible exit from the stalemate could be that the opposition accept the reality of this class division and therefore the Chávez government as a legitimate representative of the popular classes. This, however, is unlikely in the present circumstances.
The role of the senior health care worker in critical care
Authors: Ormandy Paula , Long Andrew F , Hulme Claire T , Johnson Martin
Published: June 2004

• This article identifies that the introduction of the support worker role in the critical care team facilitates flexibility when organizing and managing patient care

• Qualified nurses' time can be used more effectively, enhancing the quality of the patient care delivered

• Aspects of the qualified nurses' workload in critical care can be shared and delegated successfully to unqualified staff

• It is our view that staffing levels in critical care environments need to be reviewed with more flexible working practices to meet the current and future demands of critical care

• There is a need for national consensus amongst qualified nurses to clarify and define the role of the support worker and develop a critical care competency framework to standardize training

• To ensure proficiency, adequate training and appropriate accountability, support workers require regulation by a nationally recognized body
Ultrasound guidance for infraclavicular brachial plexus anaesthesia in children
Authors: Marhofer P. , Sitzwohl C. , Greher M. , Kapral S.
Published: June 2004

Ultrasonography may offer significant advantages in regional anaesthesia of the upper and lower limbs. It is not known if the same advantages demonstrated in adults also apply to children. We therefore performed a prospective, randomised study comparing ultrasound visualisation to conventional nerve stimulation for infraclavicular brachial plexus anasesthesia in children. Forty children scheduled for arm and forearm surgery underwent infraclavicular brachial plexus blocks with ropivacaine 0.5 ml.kg−1 guided by either nerve stimulation or ultrasound visualisation. Evaluated parameters included sensory block quality, sensory block distribution and motor block. All surgical procedures were performed under brachial plexus anaesthesia alone. Direct ultrasound visualisation was successful in all cases and was associated with significant improvements when compared with the use of nerve stimulation: lower visual analogue scores during puncture (p = 0.03), shorter mean (median) sensory onset times (9 (5–15) min vs. 15 (5–25) min, p < 0.001), longer sensory block durations (384 (280–480) min vs. 310 (210–420) min, p < 0.001), and better sensory and motor block scores 10 min afrter block insertion. Ultrasound visualisation offers faster sensory and motor responses and a longer duration of sensory blockade than nerve stimulation in children undergoing infraclavicular brachial plexus blocks. In addition, the pain associated with nerve stimulation due to muscle contractions at the time of insertion is eliminated.
Abdominal muscle action during expiration can impair pressure controlled ventilation
Authors: Prasad C. V. , Drummond G. B.
Published: June 2004

Pressure controlled ventilation, and pressure support for spontaneous breathing are often used in intensive care because coordination of the ventilator with patient efforts can improve comfort and possibly reduce sedation. However we report a series of 10 patients whose efforts did not synchronise with pressure controlled ventilation. This was incorrectly diagnosed as inadequate sedation, and treated with increased sedation or muscle paralysis. Better recognition of this condition showed that slow respiratory rates and increased abdominal muscle action during expiration can affect pressure‐controlled ventilation and pressure assisted breathing. If the condition is not recognised, treatment for poor synchronisation may delay weaning or be inappropriate.
Propofol sedation using DiprifusorTM target‐controlled infusion in adult intensive care unit patients*
Authors: McMurray T. J. , Johnston J. R. , Milligan K. R. , Grant I. S. , Mackenzie S. J. , Servin F. , Janvier G. , Glen J. B.
Published: June 2004

This multicentre, non‐comparative study investigated the range of target blood propofol concentrations required to sedate 122 adult intensive care patients when propofol was administered using DiprifusorTM target‐controlled infusion systems together with opioid analgesia. Depth of sedation was assessed with a modified Ramsay score and the target blood propofol setting was adjusted to achieve the sedation desired for each patient. A desired level of sedation was achieved for 84% of the sedation period. In postcardiac surgery patients the median time‐weighted average propofol target setting was 1.34 μg.ml−1 (10th – 90th percentiles: 0.79–1.93 μg.ml−1). Values in brain injured and general ICU patients were 0.98 (10th – 90th percentiles: 0.60–2.55) μg.ml−1 and 0.42 (10th – 90th percentiles: 0.16–1.19) μg.ml−1, respectively. Measured propofol concentrations were generally close to values predicted by the DiprifusorTM system. Target settings in the range of 0.2–2.0 μg.ml−1 are proposed for propofol sedation in this setting with titration as required in individual patients.
The ‘fixed performance’ venturi: effect of downstream pressure on outflow and FIo2
Authors: Jones J. G.
Published: June 2004

Fixed performance venturi devices should provide a predetermined oxygen concentration at an outflow which exceeds an adult's peak resting inspiratory flow rate (approximately 30 l.min−1). Campbell's original description mentioned the sensitivity of the venturi device to downstream resistance but gave no further details. This study examined outflow and oxygen concentration from the five standard venturi devices (24–60% O2) when downstream pressure increased. Outflow was exquisitely sensitive to small increases in pressure. The outflow at zero downstream pressure for the 24–40% O2 venturi devices ranged from 40 to 50 l.min−1 but only 2–3 mmH2O was needed to halve this flow and increase oxygen concentration. The 60% O2 venturi delivered a maximum of only 30 l.min−1 at zero downstream pressure and flow was reduced further by increasing this pressure. An increase in downstream pressure of only a few mmH2O increased oxygen concentration and decreased outflow of all the venturi devices tested, in most to less than normal peak tidal flow in adults.
The effects of tracheostomy cuff deflation during continuous positive airway pressure*
Authors: Conway D. H. , Mackie C.
Published: June 2004

Continuous flow positive pressure devices bridge the gap between mechanical and unsupported ventilation in patients recovering from critical illness. At this point, patients are often fully awake, yet the inflated tracheostomy cuff prevents them from speaking or swallowing. The aim of this study was to investigate the effects of cuff deflation. After ethics committee approval and informed consent, we recorded airway pressures with catheters placed 3 cm beyond the distal tracheostomy tip, respiratory rate, heart rate and peripheral oxygen saturation with continuous positive airway pressures set at 5, 7.5 and 10 cmH2O with the cuff inflated and deflated. Sixteen patients completed the study. There were small falls in end expiratory pressure on cuff deflation. The median (interquartile range) pressure drop with set airway pressure of 5 cmH2O was 0.25 (0–1.4) mmHg, which increased to 1 (0–3) mmHg at 7.5 cmH2O and 1.5 (0–4) mmHg at 10 cmH2O. These changes were not clinically significant and cardiopulmonary parameters remained stable. All patients were able to vocalise following cuff deflation. Twelve patients passed a blue dye swallow screen within a day of tolerating cuff deflation. These results suggest that pressures fall slightly following cuff deflation but this is associated with respiratory stability and may allow patients to talk and swallow.
Handover of responsibility for the anaesthetised patient – opinion and practice
Authors: Horn J. , Bell M. D. D. , Moss E.
Published: June 2004

Anaesthesia is a critical and complex process that extends from the pre‐operative assessment through to the postoperative management of patients. Handover of responsibility for logistical as opposed to patient‐orientated reasons may compromise that process of care. If such handover becomes inevitable with shift‐based patterns of working, the implications need to be considered and procedures developed in order to minimise adverse consequences. This survey of national practice reveals little formalisation of procedure and a spectrum of opinion on the relevance of the key considerations. There is, however, a majority view amongst respondents that national guidelines would be of value and that professional defensibility would be aided by standardisation and documentation of any handover.
Performance of an oxygen delivery device for weaning potentially infectious critically ill patients*
Authors: So C. Y. , Gomersall C. D. , Chui P. T. , Chan M. T. V.
Published: June 2004

Oxygen delivery via a heat and moisture exchange filter with an attached T‐shaped reservoir satisfies infection control requirements of high efficiency bacterial and viral filtration and low gas flows. In order to assess the performance of such a device in critically ill patients being weaned from mechanical ventilation, we simulated 16 patients using a human patient simulator, measuring fractional inspired oxygen and carbon dioxide concentrations and work of breathing at three oxygen flow rates. Oxygen concentration was dependent on peak inspiratory flow rate, tidal volume and oxygen flow rate. Rebreathing, as indicated by inspired carbon dioxide concentration, was greatest at high respiratory rates and low tidal volumes. Imposed inspiratory work of breathing was relatively high (mean 0.88 J.l−1[SD 0.30]). We conclude that this method of oxygen delivery is only suitable for patients in whom rapid extubation is anticipated.
Difficult Airway Society guidelines for management of the unanticipated difficult intubation
Authors: Henderson J. J. , Popat M. T. , Latto I. P. , Pearce A. C.
Published: June 2004

Problems with tracheal intubation are infrequent but are the most common cause of anaesthetic death or brain damage. The clinical situation is not always managed well. The Difficult Airway Society (DAS) has developed guidelines for management of the unanticipated difficult tracheal intubation in the non‐obstetric adult patient without upper airway obstruction. These guidelines have been developed by consensus and are based on evidence and experience. We have produced flow‐charts for three scenarios: routine induction; rapid sequence induction; and failed intubation, increasing hypoxaemia and difficult ventilation in the paralysed, anaesthetised patient. The flow‐charts are simple, clear and definitive. They can be fully implemented only when the necessary equipment and training are available. The guidelines received overwhelming support from the membership of the DAS.

Disclaimer: It is not intended that these guidelines should constitute a minimum standard of practice, nor are they to be regarded as a substitute for good clinical judgement.
Pharmacokinetics and pharmacodynamics of terbogrel, a combined thromboxane A2 receptor and synthase inhibitor, in healthy subjects
Authors: Guth Brian D. , Narjes Hans , Schubert Hans‐Dieter , Tanswell Paul , Riedel Axel , Nehmiz Gerhard
Published: June 2004

Aims

To characterize the pharmacokinetics of terbogrel, a new combined thromboxane A2 (TxA2) receptor and synthase inhibitor, in healthy human subjects after single or multiple oral administration.

Methods

Forty‐eight healthy male subjects received a single oral dose (10, 25, 50, 100, 150 or 200 mg) of terbogrel or placebo and 32 different subjects received one of the following treatments twice daily for 7 days: 50, 100 or 150 mg terbogrel, placebo, or once‐a‐day 330 mg acetylsalicylic acid.

Results

Terbogrel was well tolerated without obvious adverse effects following either a single oral dose or administration over 7 days. Plasma drug concentrations were dose‐linear and there was no accumulation over 7 days. There was a dose‐dependent blockade of TxA2 receptors and of inhibition of thromboxane synthase activity with values for IC50 of 12 ng ml−1 and 6.7 ng ml−1, respectively. At the highest dose tested (150 mg) there was almost complete inhibition of thomboxane synthase and thromboxane receptor occupancy. Even at trough concentrations, receptor occupancy remained above 80% and thromboxane synthase was still completely inhibited. These two activities were associated with a dose‐dependent inhibition of platelet aggregation (>80% at the 150 mg dose of terbogrel) and enhanced prostacyclin production.

Conclusions

Terbogrel is a potent agent having two distinct, complimentary pharmacodynamic actions, namely inhibition of thromboxane synthase and antagonism of the TxA2 receptor. The antithrombotic effect of terbogrel was dose‐dependent and was associated with enhanced prostacyclin production. Terbogrel is an attractive candidate for long‐term antithrombotic therapy.
Iohexol contrast medium induces QT prolongation in amiodarone patients
Authors: Goernig Matthias , Kirmeier Thomas , Krack Andreas , Hartog Christiane S. , Figulla Hans R. , Leder Uwe
Published: June 2004

Aims

Amiodarone is widely used in ventricular tachyarrhythmias and atrial fibrillation, known to prolong QT‐intervals. Concurrent administration of drugs prolonging QT‐ time can induce life‐threatening ventricular tachyarrhythmia.

Methods

QT‐interval changes following use of Iohexol contrast‐medium for coronarangiography were observed comparing 21 patients taking long‐term amiodarone therapy with 21 controls not taking amiodarone or QT‐prolonging drugs retrospectively.

Results

Concurrent use of Iohexol and amiodarone was associated with significant prolongation of QTc‐interval (433, 95%CI: 419–448 ms vs. 480, 95%CI: 422–483 ms, P < 0.001) the day after coronarangiograpgy. 6/21 patients showed severe prolonged QTc‐interval of >500 ms.

Conclusion

Caution is advised until more is known about pro‐arrhythmic effects of Iohexol.
Phenotypic and functional characteristics of CD28+ and CD28− cells from chagasic patients: distinct repertoire and cytokine expression
Authors: MENEZES C A S , ROCHA M O C , SOUZA P E A , CHAVES A C L , GOLLOB K J , DUTRA W O
Published: June 2004

Chronic human Chagas’ disease ranges from an asymptomatic to a severe cardiac clinical form. The involvement of the host's immune response in the development and maintenance of chagasic pathology has been demonstrated by several groups. We have shown that activated T-cells lacking CD28 expression are increased in the peripheral blood of chagasic patients (CP), suggesting a relationship between these cells and disease. In order to better characterize this cell population, determining their possible role in immunoregulation of human Chagas’ disease, we evaluated the expression of TCR-Vbeta regions 2, 3·1, 5, 8 and 17, as well as the expression of IFN-γ, TNF-α, IL-4 and IL-10 by CD28+ and CD28− cells from polarized indeterminate and cardiac CP. Flow cytometric analysis demonstrated equivalent TCR-Vbeta usage between CD4+CD28+ and CD4+CD28− cells from all groups (chagasic and healthy controls). However, there was a predominance of Vbeta5 expression in the CD28+ and CD28− populations in the CP groups (indeterminate and cardiac). Interestingly, CD8+CD28− cells from CP, but not from nonchagasic individuals, displayed a reduced frequency of most analysed Vbetas when compared with the CD8+CD28+ subpopulation. Comparison of V-beta expression in CD28+ or CD28− cell populations among individuals from different groups also showed several interesting differences. Functionally, cardiac CP displayed a higher frequency of IFN-γ, TNF-α and IL-4 producing lymphocytes than indeterminate CP. Correlation analysis between the frequency of cytokine expressing cells, and the frequency of CD4+ T-cells with differential expression of CD28 demonstrated that CD4+CD28− T-cells were positively correlated with TNF-α in cardiac and with IL-10 in indeterminate CP, suggesting that these cells might have an important regulatory role in human Chagas’ disease.
Systemic complement activation following human acute ischaemic stroke
Authors: PEDERSEN E D , WAJE-ANDREASSEN U , VEDELER C A , AAMODT G , MOLLNES T E
Published: June 2004

The brain tissue damage after stroke is mediated partly by inflammation induced by ischaemia–reperfusion injury where the complement system plays a pivotal role. In the present study we investigated systemic complement activation and its relation to C-reactive protein (CRP), a known complement activator, and other inflammatory mediators after acute ischaemic stroke. Sequential plasma samples from 11 acute stroke patients were obtained from the time of admittance to hospital and for a follow-up period of 12 months. Nine healthy gender- and age-matched subjects served as controls. The terminal SC5b-9 complement complex (TCC), CRP, soluble adhesion molecules (L-, E- and P- selectin, ICAM, VCAM) and cytokines [tumour necrosis factor (TNF)-α, interleukin (IL)-1β, IL-8] were analysed. All parameters were within normal values and similar to the controls the first hours after stroke. Terminal complement complex (TCC) increased significantly from 0·54 to 0·74 AU/ml at 72 h (P = 0·032), reached maximum at 7 days (0·90 AU/ml, P < 0·001), was still significantly increased at 12 days (0·70 AU/ml, P = 0·009) and thereafter normalized. CRP increased significantly from 1·02 to 2·11 mg/l at 24 h (P = 0·023), remained significantly increased for 1 week (2·53–2·94 mg/l, P = 0·012–0·017) and thereafter normalized. TCC and C-reactive protein (CRP) correlated significantly (r = 0·36, P < 0·001). The increase in TCC and CRP correlated to the size of infarction (r = 0·80 and P = 0·017 for TCC; r = 0·72 and P = 0·043 for CRP). No significant changes were seen for adhesion molecules and cytokines. In conclusion, transitory systemic complement activation takes place after stroke. The early rise in CRP and the following TCC increase suggest a possible role for CRP in complement activation, which may contribute to inflammation after stroke.
Screening of a HUAEC cDNA library identifies actin as a candidate autoantigen associated with carotid atherosclerosis
Authors: MARGUTTI P , DELUNARDO F , SORICE M , VALESINI G , ALESSANDRI C , CAPOANO R , PROFUMO E , SIRACUSANO A , SALVATI B , RIGANÒ R , ORTONA E
Published: June 2004

The humoral immune response to endothelium has a pivotal role in the development of atherosclerosis. Using a molecular method, we sought to identify endothelial autoantigens in carotid atherosclerosis. Immunoscreening of a HUAEC expression library with IgG from a pool of two sera from patients with carotid atherosclerosis identified a clone specific to actin. We evaluated actin-specific IgG reactivity in patients with carotid atherosclerosis and compared responses with those in patients with systemic lupus erythematosus and type 1 diabetes mellitus and in healthy subjects. Enzyme-linked immunoassay detected actin-specific IgG in a significantly higher percentage of sera from patients with atherosclerosis and systemic lupus erythematosus than from healthy subjects (16/61, 26% and 13/33, 39%versus 2/41, 5%, P = 0·012 and P < 10−4, by χ2 test). Mean optical density values were significantly higher in patients than in healthy subjects (P < 10−4 by Student's t-test). Patients with atherosclerosis and uncomplicated plaques had significantly higher serum anti-actin IgG reactivity than those with complicated plaques (P = 0·048 by Student's t-test). Our findings suggest that actin is an autoantigenic molecule of potential clinical interest in carotid atherosclerosis.
The impact of an early truncating founder ATM mutation on immunoglobulins, specific antibodies and lymphocyte populations in ataxia-telangiectasia patients and their parents
Authors: STRAY-PEDERSEN A , JÓNSSON T , HEIBERG A , LINDMAN C R , WIDING E , AABERGE I S , BORRESEN-DALE A L , ABRAHAMSEN T G
Published: June 2004

Eleven Norwegian patients (aged 2–33 years, seven males and four females) with Ataxia-telangiectasia (A-T) and their parents were investigated. Five of the patients were homozygous for the same ATM mutation, 3245delATCinsTGAT, a Norwegian founder mutation. They had the lowest IgG2 levels; mean (95% confidence interval) 0·23 (0·05–0·41) g/l versus 0·91 (0·58–1·26) g/l in the other patients (P = 0·002). Among the 11 A-T patients, six had IgG2 deficiency, six had IgA deficiency (three in combination with IgG2 deficiency) and seven had low/undetectable IgE values. All patients had very low levels of antibodies to Streptococcus pneumoniae 0·9 (0·4–1·4) U/ml, while normal levels were found in their parents 11·1 (8·7–13·4) U/ml (P < 0·001). A positive linear relationship between pneumococcal antibodies and IgG2 (r = 0·85, P = 0·001) was found in the patients. Six of 11 had diphtheria antibodies and 7 of 11 tetanus antibodies after childhood vaccinations, while 4 of 7 Hemophilus influenzae type b (Hib) vaccinated patients had protective antibodies. Ten patients had low B cell (CD19+) counts, while six had low T cell (CD3+) counts. Of the T cell subpopulations, 11 had low CD4+ cell counts, six had reduced CD8+ cell counts, and four had an increased portion of double negative (CD3+/CD4-/CD8-) gamma delta T cells. Of the 22 parents (aged 23–64 years) 12 were heterozygous for the ATM founder mutation. Abnormalities in immunoglobulin levels and/or lymphocyte subpopulations were also observed in these carriers, with no correlation to a special ATM genotype.
The tetraspanin CD9 is preferentially expressed on the human CD4+CD45RA+ naive T cell population and is involved in T cell activation
Authors: KOBAYASHI H , HOSONO O , IWATA S , KAWASAKI H , KUWANA M , TANAKA H , DANG N H , MORIMOTO C
Published: June 2004

Human CD4+ T cells can be divided into reciprocal memory and naive T cell subsets based on their expression of CD45 isoforms and CD29/integrin beta1 subunit. To identify unique cell surface molecules on human T cells, we developed a new monoclonal antibody termed anti5H9. Binding of anti5H9 triggers a co-stimulatory response in human peripheral blood T cells. Retrovirus-mediated expression cloning has revealed that the antigen recognized by anti5H9 is identical to the tetraspanin CD9. We now show that human CD9 is preferentially expressed on the CD4+CD45RA+ naive T cell subset, and that CD9+CD45RA+ T cells respond preferentially to the recombinant beta2-glycoprotein I, compared to CD9–CD45RA+ T cells. Furthermore, anti5H9 inhibits both the recombinant beta2-glycoprotein I- and the recall antigen tetanus toxoid-specific T cell proliferation. These results suggest that the tetraspanin CD9 plays an important role in T cell activation.
Effect of maternal anti-HPA-1a antibodies and polyclonal IVIG on the activation status of vascular endothelial cells
Authors: RADDER C M , BEEKHUIZEN H , KANHAI H H H , BRAND A
Published: June 2004

Maternal anti-HPA-1a antibodies can cause severe fetal and neonatal alloimmune thrombocytopenia (FNAIT), complicated by intracranial haemorrhage (ICH). Antenatal treatment with maternal intravenous immunoglobulin (IVIG) seems to protect against ICH even when thrombocytopenia persists. The aim of this study was to investigate if anti-HPA-1a antibodies and IVIG potentially affect vascular endothelial cells (ECs) in order to identify susceptibility for ICH. Human umbilical cord endothelial cells (HUVEC) were incubated with anti-HPA-1a antibodies with or without polyclonal IVIG and evaluated for EC activation. Maternal sera with anti-HPA-1a antibodies affected neither the EC expression of intracellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1) and tissue factor (TF) nor the release of van Willebrand factor (vWF) or interleukin (IL)-8 nor the integrity of ECs. Maternal sera obtained after IVIG treatment and polyclonal IVIG decrease constitutive and cytokine-induced ICAM-1 and VCAM-1 expression on ECs. The results show that maternal anti-HPA-1a antibodies cause no activation or damage of ECs in this model. The clinical relevance of the de-activating properties of IVIG on EC activation with respect to ICH deserves further investigation.
Adjuvant oil induces waves of arthritogenic lymph node cells prior to arthritis onset
Authors: HOLM B C , LORENTZEN J C , BUCHT A
Published: June 2004

A single intradermal injection of the adjuvant-oil squalene induces T cell mediated arthritis in DA rats. The chain of events leading from nonspecific provocation of the immune system to arthritis is largely unknown. Previous studies have demonstrated that lymph node (LN) cells are of pathogenic importance, i.e. cells from LNs draining the injection site can transfer arthritis to naïve DA rats. Recently we have demonstrated cellular uptake of adjuvant oil in draining lymph nodes but also that nondraining LNs become hyperplastic and harbour arthritogenic cells. Here, we aimed to determine from which time-point prior to arthritis onset arthritogenic cells appear in draining inguinal and nondraining axillary/brachial LNs, respectively. We demonstrated that the ability to transfer arthritis was strongly dependent on the time-point after adjuvant-injection with clear-cut differences between draining and nondraining LN cells. Cells harvested at day 5 postinjection (p.i) were not able to transfer arthritis, while at day 8 p.i, a first wave of arthritogenic cells appeared in draining LNs. The ability to transfer arthritis was associated with a pro-inflammatory cytokine profile as indicated by the IL-1β and IFNγ expression in cells from draining LNs. Subsequently, at day 11 p.i., just before arthritis onset, arthritogenic cells appeared also in nondraining LNs. These results shed new light on the induction of arthritic diseases, implicating a two step mechanism for the development of pathogenic cells. Firstly, a pro-inflammatory burst in responding lymphoid organs leading to a local pool of arthritogenic cells and, secondly, a transmission of arthritogenecity to other LNs and precipitation of disease in peripheral joints.