Background: We previously reported associations between organochlorines and behaviors related to attention deficit hyperactivity disorder among boys and girls at 8 years of age using a teacher’s rating scale for a birth cohort in New Bedford, Massachusetts (USA).
Objectives: Our goal was to corroborate these findings using neuropsychological measures of inattentive and impulsive behaviors.
Methods: We investigated the association between cord serum polychlorinated biphenyls (PCBs) and p,p´-dichlorodiphenyl dichloroethylene (p,p´-DDE) and attention and impulse control using a Continuous Performance Test (CPT) and components of the Wechsler Intelligence Scale for Children, 3rd edition (WISC-III). Participants came from a prospective cohort of children born during 1993–1998 to mothers residing near a PCB-contaminated harbor in New Bedford. Median (range) cord serum levels for the sum of four prevalent PCBs [congeners 118, 138, 153, and 180 (ΣPCB4)] and p,p´-DDE were 0.19 (0.01–2.59) and 0.31 (0–14.93) ng/g serum, respectively.
Results: We detected associations between PCBs and neuropsychological deficits for 578 and 584 children with CPT and WISC-III measures, respectively, but only among boys. For example, boys with higher exposure to ΣPCB4 had a higher rate of CPT errors of omission [rate ratio for the exposure interquartile range (IQR) = 1.12; 95% confidence interval (CI): 0.98, 1.27] and slower WISC-III Processing Speed (change in score for the IQR = –2.0; 95% CI: –3.5, –0.4). Weaker associations were found for p,p´-DDE. For girls, associations were in the opposite direction for the CPT and null for the WISC-III.
Conclusions: These results support an association between organochlorines (mainly PCBs) and neuropsychological measures of attention among boys only. Sex-specific effects should be considered in studies of organochlorines and neurodevelopment.
attention deficit hyperactivity disorder; p,p´-dichlorodiphenyl dichloroethylene (p,p´-DDE); epidemiology; maternal exposure; organochlorines; polychlorinated biphenyls (PCBs)
The objective of this experiment was to measure the change in female index (FI) of Heterodera glycines from bioassays on Bedford, Peking, PI 89772, and PI 90763 soybean (Glycine max) for 12 cropping sequence treatments over a 10-year period. Cropping sequences included continuous plantings of Forrest, Peking, and D72-8927 soybean (all resistant to race 3); Bedford, Nathan, and D75-10710 soybean (all resistant to races 3 and 14); a Bedford-corn (Zea mays) rotation; a rotation of Bedford, Essex (susceptible), and Forrest; and a 70:30 blend of Bedford and Forrest. The FI from bioassays with PI 89772 and PI 90763 decreased over time from 24.3 to 1.6 with treatments involving continuous Bedford, Nathan, and D75-10710 and the Bedford-corn rotation. The FI increased in bioassays using Bedford with treatments involving Bedford, Nathan, D75-10710, the Bedford-Forrest blend, and the two rotations. Results of this field experiment confirm greenhouse experiments in which reciprocal changes occur in FI on PI 89772 and PI 90673 compared with FI on Bedford.
cropping sequence; genetics; Glycine max; Heterodera glycines; nematode; race; resistance; rotation; soybean; soybean cyst nematode
The protection of personnel against high air and radiant temperatures is a problem that has been confronting industry for many years now, and for many industrial situations it still has not been solved. The experiments reported here were intended to determine the most suitable form of insulation for a hot entry suit for use primarily in furnace wrecking where mean radiant temperatures of 200°C. are met and where heat-reflecting garments are unsuitable due to the rapid deterioration of the reflecting surface.
From a preliminary consideration of the problem it was concluded that a ventilated garment was required and that conventional ventilated garments in which air is induced to flow parallel to the body surfaces (axial ventilation) are basically unsound in design as the air is not utilized for the transfer of heat in the most efficient manner. A new form of ventilation was therefore developed in which air flows out through a permeable suit (radial ventilation). This form of ventilation produces what is called dynamic insulation, and this method of insulation, when compared with two alternative methods on a physical model, was found to be very effective.
The model experiments were confirmed by comparative trials of three ventilated suits each using one of three different forms of insulation thought to be suitable for use in heat-protective clothing.
Physiological measurements made on the subjects and physical measurement made on the suits confirmed that dynamic insulation is the most suitable insulation for a hot entry suit for furnace wrecking.
With the air flows used in these experiments, dynamic insulation had a thermal conductance one-fifth that of conventional static insulation, and sweat losses and oral temperature rises were reduced by one-third and one-half respectively.
The basic principle of graph-based approaches for image segmentation is to interpret an image as a graph, where the nodes of the graph represent 2D pixels or 3D voxels of the image. The weighted edges of the graph are obtained by intensity differences in the image. Once the graph is constructed, the minimal cost closed set on the graph can be computed via a polynomial time s-t cut, dividing the graph into two parts: the object and the background. However, no segmentation method provides perfect results, so additional manual editing is required, especially in the sensitive field of medical image processing. In this study, we present a manual refinement method that takes advantage of the basic design of graph-based image segmentation algorithms. Our approach restricts a graph-cut by using additional user-defined seed points to set up fixed nodes in the graph. The advantage is that manual edits can be integrated intuitively and quickly into the segmentation result of a graph-based approach. The method can be applied to both 2D and 3D objects that have to be segmented. Experimental results for synthetic and real images are presented to demonstrate the feasibility of our approach.
Segmentation; Graph-based; Manual refinement; 2D; 3D
Populations of Heterodera glycines identifiable as race 1 reproduced on the race 1 resistant 'Bedford' soybean. A Beaufort County, North Carolina, population had an index of parasitism of 112% on Bedford in greenhouse tests. Indices of parasitism for this population on race 1 resistant cultivars Pickett 71, Centennial, and Forrest were less than 10%. The Beaufort County population had significantly greater reproduction on Bedford in microplots than did populations of race 3 or race 4. In field tests, a race 1 population suppressed yields of Bedford but not yields of Centennial. Based on these data, Bedford is no longer recommended in North Carolina as a race 1 resistant cultivar.
host resistance; soybean cyst nematode; nematode management; soybean; reproduction
Collection of exhaled breath condensate (EBC) is a non-invasive means of sampling the airway-lining fluid of the lungs. EBC contains numerous measurable mediators, whose analysis could change the management of patients with certain pulmonary diseases.
While initially popularized in investigations involving spontaneously breathing patients, an increasing number of studies have been performed using EBC in association with mechanical ventilation. Collection of EBC in mechanically ventilated patients follows basic principles of condensation, but is influenced by multiple factors. Effective collection requires selection of a collection device, adequate minute ventilation, low cooling temperatures, and sampling times of greater than ten minutes. Condensate can be contaminated by saliva, which needs to be filtered. Dilution of samples occurs secondary to distilled water in vapors and humidification in the ventilator circuit. Dilution factors may need to be employed when investigating non-volatile biomarkers. Storage and analysis should occur promptly at −70° C to −80° C to prevent rapid degradation of samples.
The purpose of this review is to examine and describe methodologies and problems of EBC collection in mechanically ventilated patients. A straightforward and safe framework has been established to investigate disease processes in this population, yet technical aspects of EBC collection still exist that prevent clinical practicality of this technology. These include a lack of standardization of procedure and analysis of biomarkers, and of normal reference ranges for mediators in healthy individuals. Once these procedural aspects have been addressed, EBC could serve as a non-invasive alternative to invasive evaluation of lungs in mechanically ventilated patients.
Exhaled breath condensate; Biomarkers; Inflammation; Mechanical ventilation; Airway-lining fluid
The provision of mechanical ventilation for the support of infants and children with respiratory failure or insufficiency is one of the most common techniques that are performed in the Pediatric Intensive Care Unit (PICU). Despite its widespread application in the PICUs of the 21st century, before the 1930s, respiratory failure was uniformly fatal due to the lack of equipment and techniques for airway management and ventilatory support. The operating rooms of the 1950s and 1960s provided the arena for the development of the manual skills and the refinement of the equipment needed for airway management, which subsequently led to the more widespread use of endotracheal intubation thereby ushering in the era of positive pressure ventilation. Although there seems to be an ever increasing complexity in the techniques of mechanical ventilation, its successful use in the PICU should be guided by the basic principles of gas exchange and the physiology of respiratory function. With an understanding of these key concepts and the use of basic concepts of mechanical ventilation, this technique can be successfully applied in both the PICU and the operating room. This article reviews the basic physiology of gas exchange, principles of pulmonary physiology, and the concepts of mechanical ventilation to provide an overview of the knowledge required for the provision of conventional mechanical ventilation in various clinical arenas.
Mechanical ventilation; respiratory failure; ventilatory support
Over the past decade, concepts of control of breathing have increasingly moved from being theoretical concepts to “real world” applied science. The purpose of this review is to examine the basics of control of breathing, discuss the bidirectional relationship between control of breathing and mechanical ventilation, and critically assess the application of this knowledge at the patient’s bedside. The principles of control of breathing remain under-represented in the training curriculum of respiratory therapists and pulmonologists, whereas the day-to-day bedside application of the principles of control of breathing continues to suffer from a lack of outcomes-based research in the intensive care unit. In contrast, the bedside application of the principles of control of breathing to ambulatory subjects with sleep-disordered breathing has out-stripped that in critically ill patients. The evolution of newer technologies, faster real-time computing abilities, and miniaturization of ventilator technology can bring the concepts of control of breathing to the bedside and benefit the critically ill patient. However, market forces, lack of scientific data, lack of research funding, and regulatory obstacles need to be surmounted.
artificial respiration; mechanical ventilation; ventilator; obstructive sleep apnea; sleep apnea; servo ventilation; critical illness
In plants, RNA editing is a process that converts specific cytidines to uridines and uridines to cytidines in transcripts from virtually all mitochondrial protein-coding genes. There are thousands of plant mitochondrial genes in the sequence databases, but sites of RNA editing have not been determined for most. Accurate methods of RNA editing site prediction will be important in filling in this information gap and could reduce or even eliminate the need for experimental determination of editing sites for many sequences. Because RNA editing tends to increase protein conservation across species by "correcting" codons that specify unconserved amino acids, this principle can be used to predict editing sites by identifying positions where an RNA editing event would increase the conservation of a protein to homologues from other plants. PREP-Mt takes this approach to predict editing sites for any protein-coding gene in plant mitochondria.
To test the general applicability of the PREP-Mt methodology, RNA editing sites were predicted for 370 full-length or nearly full-length DNA sequences and then compared to the known sites of RNA editing for these sequences. Of 60,263 cytidines in this test set, PREP-Mt correctly classified 58,994 as either an edited or unedited site (accuracy = 97.9%). PREP-Mt properly identified 3,038 of the 3,698 known sites of RNA editing (sensitivity = 82.2%) and 55,956 of the 56,565 known unedited sites (specificity = 98.9%). Accuracy and sensitivity increased to 98.7% and 94.7%, respectively, after excluding the 489 silent editing sites (which have no effect on protein sequence or function) from the test set.
These results indicate that PREP-Mt is effective at identifying C to U RNA editing sites in plant mitochondrial protein-coding genes. Thus, PREP-Mt should be useful in predicting protein sequences for use in molecular, biochemical, and phylogenetic analyses. In addition, PREP-Mt could be used to determine functionality of a mitochondrial gene or to identify particular sequences with unusual editing properties. The PREP-Mt methodology should be applicable to any system where RNA editing increases protein conservation across species.
In the present issue of Critical Care, Frank and Matthay review the physiologic mechanisms that lead to ventilator-induced lung injury. Our greater understanding of basic physiologic principles has already had a major impact on the treatment of critically ill patients. Novel strategies to limit ventilator-induced lung injury have now been shown to improve survival. However, there has been debate in the literature regarding the safety and efficacy of the Acute Respiratory Distress Syndrome (ARDS) Network study protocol in reducing ventilator-induced lung injury. The issues surrounding the ARDS Network protocol and a recent meta-analysis criticizing its use are presented. As clinicians, we now have the responsibility to ensure that our patients benefit from these recent developments.
acute respiratory distress syndrome; ARDS Network; lung injury; lung protective strategy; mechanical ventilation
Isolates from a race 5 field population of Heterodera glycines were cultured separately on soybean cultivars 'Bedford' (resistance derived from Peking and plant introduction [PI] 88788) and 'Cordell' (resistance derived from 'Peking', PI 88788, and PI 90763) for 10, 12, and 14 generations. Reproduction was measured of the 10th, 12th, and 14th generations on Bedford and Cordell and on Peking, 'Pickett', PI 88788, PI 90763, and 'Lee' (the soybean lines that are used to determine H. glycines race). The isolate cultured on Bedford remained race 5, whereas the isolate cultured on Cordell changed to race 14, to which Bedford is moderately resistant. Cordell probably derived its race 5 resistance from either Peking or PI 90763 because the isolate resulting from culture on Cordell reproduced on the H. glycines race differentials in a pattern similar to those of other isolates selected on PI 90763 in previous studies. Rotation of cultivars with pedigrees similar to Bedford and Cordell may be effective in managing H. glycines to prevent yield suppression in soybean and the development of new races.
Glycine max; Heterodera glycines; nematode; race; resistance; selection; soybean; soybean cyst nematode
RNA editing in higher plant plastids changes single cytidine residues to uridine through an unknown mechanism. In order to investigate the relation of editing to physiological processes and to other steps in plastid gene expression, we have tested the sensitivity of chloroplast RNA editing to heat shock and antibiotics. We show that heat shock conditions as well as treatment of plants with prokaryotic translational inhibitors can inhibit plastid RNA editing. Surprisingly, this inhibitory effect is confined to a limited number of plastid editing sites suggesting that some site-specific factor(s) but none of the general components of the plastid RNA editing machinery are compromised. Contrary to previous expectations, our results provide evidence for a role of plastid translation in RNA editing.
This demonstration shows the Profiles in
Science® digital library. Profiles in Science
contains digitized selections from the personal manuscript collections of
prominent biomedical researchers, medical practitioners, and those fostering
science and health. The Profiles in Science Web site1 is the delivery mechanism for
content derived from the digital library system. The system is designed
according to our basic principles for digital library development . The digital library includes the rules
and software used for digitizing items, creating and editing database records
and performing quality control as well as serving the digital content to the
public. Among the types of data managed by the digital library are detailed
item-level, collection-level and cross-collection metadata, digitized
photographs, papers, audio clips, movies, born-digital electronic files, optical
character recognized (OCR) text, and annotations (see Figure 1). The digital library also tracks the status of
each item, including digitization quality, sensitivity of content, and
copyright. Only items satisfying all required criteria are released to the
public through the World Wide Web. External factors have influenced all aspects
of the digital library's infrastructure.
H.3.7 [Information Storage and Retrieval]: Digital
Libraries –; Collection; Dissemination; Systems issues; Design; Legal Aspects; Digital Library; Information System; Digitized Manuscripts; Adaptability
A field infested with Rotylenchulus reniformis in the Arkansas River valley near Pine Bluff, Jefferson County, Arkansas, was used to test the effects of R. reniformis on four commonly grown soybean cultivars (Lloyd, Tracy-M, Bedford, Forrest). At planting, the plots averaged 950 vermiform reniform nematodes per 100 cm³ of soil. At harvest, the average R. reniformis reproductive index (final/initial population density) was 2.62 for Tracy-M, 2.50 for Lloyd, 1.72 for Bedford, and 0.81 for Forrest. Yields were highest for the cultivar Lloyd, followed by Bedford, Forrest, and Tracy-M. Initial population densities of R. reniformis were positively correlated (P = 0.05) with final population densities when all cultivars were calculated together. Neither initial nor final densities were correlated with yield.
Glycine max; Heterodera glycines; nematode; reniform nematode; resistance; Rotylenchulus reniformis; soybean; yield
Alternate planting dates and periodic destruction of the previous year's soybean crop as well as 1-year bare fallow were used to establish a range of population densities ofHeterodera glycines for the subsequent year. Soybean cultivar Coker 156 (susceptible, moderately tolerant) was compared to cultivars Essex (susceptible, intolerant) and Bedford (resistant) to evaluate tolerance at different H. glycines population densities established through the previous year's treatments. Yield of Coker 156 was consistently intermediate between yields of Bedford and Essex in 1986 and 1987. Yield of Essex was negatively correlated (P = 0.05) with preplant egg numbers of H. glycines in 1987, whereas yield of Bedford and Coker 156 were not related to nematode density. Reproduction of H. glycines was greater (P = 0.05) on the moderately tolerant Coker 156 than on either of the other cultivars.
Glycine max; Heterodera glycines; nematode; soybean; soybean cyst nematode; tolerance
Selection for ability of soybean cyst nematode (SCN), Heterodera glycines, to reproduce on soybeans with different sources of resistance divides some SCN race 4 field populations into two distinct subpopulations. These subpopulations reproduce well on 'Bedford' and plant introduction (PI) 88788 or PI 89772 and PI 90763 but not on both pairs of soybean lines. The ability of these subpopulations to reproduce on the four soybean lines was reversed by changing the soybean line used as a host during a second cycle of selection. When SCN populations previously selected for reproduction on Bedford and PI 88788 were selected for their ability to reproduce on D72-8927 and J74-88, the ability of these populations to reproduce on Bedford and PI 88788 decreased significantly and their ability to reproduce on PI 89772 and PI 90763 increased significantly. Conversely, when SCN populations, previously selected for reproduction on P189772 and P190763, were selected for their ability to reproduce on Bedford, the reproduction of these populations on Bedford increased significantly and reproduction on PI 89772 and PI 90763 decreased significantly. Selection for ability of a SCN race 4 field population to reproduce on soybean lines derived from SCN race 4 resistant PIs resulted in the same division of the field population into two distinct subpopulations. These data substantiate earlier proposals to rotate cultivars with different genes for SCN resistance as a means of managing SCN populations.
races; resistance; soybean; soybean cyst nematode
Over the past few decades, continuous positive airway pressure (CPAP) therapy for obstructive sleep apnea has evolved into more and more sophisticated modes of therapy for various forms of sleep-disordered breathing. While the principles of splinting the airway and delivering assisted ventilation underpin the basics of this therapy, the introduction of newer technologies and miniaturization are revolutionizing the former conventions of the field. The purpose of this review is to improve our understanding of various forms of PAP therapy by providing the rationale for such modalities, gaining a basic working knowledge of device technology, and critically assessing the clinical research evidence while identifying barriers to implementation. Dissemination of such information is vital in order to prevent knowledge gaps in healthcare providers and systems.
obstructive sleep apnea; continuous positive airway pressure; adherence; adult; pediatric; compliance; sleep apnea; artificial respiration; central sleep apnea; servo ventilation; obesity
A humidifier system for neonatology that functions according to the 'membrane humidification' principle was subjected to a performance test in our laboratory. Humidification and heating of the respiratory gases took place in a module consisting of a net of hollow fibres placed inside the incubator. In 18 measurement combinations flow, respiratory gas temperature, and incubator temperature were varied. At respiratory gas temperatures within the range of 33-37 degrees C the minimum international standard for the absolute air humidity in the respiratory gas was achieved or exceeded in all measurements. No controlled clinical tests regarding the importance and long term effects of different temperatures and different humidity levels in the inspiratory air are yet available for the ventilation treatment of neonates.
Homeostasis is a basic tenet of biomedicine and an open problem for many physiological control systems. Among them, none has been more extensively studied and intensely debated than the dilemma of exercise hyperpnea – a paradoxical homeostatic increase of respiratory ventilation that is geared to metabolic demands instead of the normal chemoreflex mechanism. Classical control theory has led to a plethora of “feedback/feedforward control” or “set point” hypotheses for homeostatic regulation, yet so far none of them has proved satisfactory in explaining exercise hyperpnea and its interactions with other respiratory inputs. Instead, the available evidence points to a far more sophisticated respiratory controller capable of integrating multiple afferent and efferent signals in adapting the ventilatory pattern toward optimality relative to conflicting homeostatic, energetic and other objectives. This optimality principle parsimoniously mimics exercise hyperpnea, chemoreflex and a host of characteristic respiratory responses to abnormal gas exchange or mechanical loading/unloading in health and in cardiopulmonary diseases – all without resorting to a feedforward “exercise stimulus”. Rather, an emergent controller signal encoding the projected metabolic level is predicted by the principle as an exercise-induced ‘mental percept’ or ‘internal model’, presumably engendered by associative learning (operant conditioning or classical conditioning) which achieves optimality through continuous identification of, and adaptation to, the causal relationship between respiratory motor output and resultant chemical-mechanical afferent feedbacks. This internal model self-tuning adaptive control paradigm opens a new challenge and exciting opportunity for experimental and theoretical elucidations of the mechanisms of respiratory control – and of homeostatic regulation and sensorimotor integration in general.
European Guidelines for Quality Assurance in Cervical Cancer Screening have been initiated in the Europe Against Cancer Programme. The first edition established the principles of organised population-based screening and stimulated numerous pilot projects. The second multidisciplinary edition was published in 2008 and comprises ∼250 pages divided into seven chapters prepared by 48 authors and contributors. Considerable attention has been devoted to organised, population-based programme policies which minimise adverse effects and maximise benefits of screening. It is hoped that this expanded guidelines edition will have a greater impact on countries in which screening programmes are still lacking and in which opportunistic screening has been preferred in the past. Other methodological aspects such as future prospects of human papillomavirus testing and vaccination in cervical cancer control have also been examined in the second edition; recommendations for integration of the latter technologies into European guidelines are currently under development in a related project supported by the European Union Health Programme. An overview of the fundamental points and principles that should support any quality-assured screening programme and key performance indicators are presented here in a summary document of the second guidelines edition in order to make these principles and standards known to a wider scientific community.
cervical cancer; cervical intraepithelial neoplasia; Europe; guidelines; quality assurance; screening
RNA editing regulates mitochondrial gene expression in trypanosomatid pathogens by creating functional mRNAs. It is catalyzed by a multi-protein complex (the editosome), and is found to be essential in both insect stage and mammalian blood stream form of Trypanosoma brucei. This particular form of RNA editing is unique to trypanosomatids, and thus provides a suitable drug target in trypanosomatid pathogens. Here, we demonstrate the feasibility of a rapid and sensitive fluorescence-based reporter assay to monitor RNA editing based on ribozyme activity. We could validate our new assay using previously identified inhibitors against the essential RNA editing ligase. The principle advantages of this assay are: (i) the use of non-radioactively labeled materials, (ii) sensitivity afforded by fluorescence instrumentation applicable to high-throughput screening of chemical inhibitors against the essential editosome and (iii) a rapid and convenient ‘mix and measure’ type of assay in low volume with a high signal to noise ratio. This assay should enhance rapid identification and characterization of the editosome inhibitors primarily based on the overall composition of the editosomes from T. brucei. These inhibitors could also be tested against the editosomes from the closely related pathogens including T. cruzi and Leishmania species.
RNA editing alters plant mitochondrial and chloroplast transcripts by converting specific cytidines to uridines, which usually results in a change in the amino acid sequence of the translated protein. Systematic studies have experimentally identified sites of RNA editing in organellar transcriptomes from several species, but these analyses have not kept pace with rate of genome sequencing. The PREP (predictive RNA editors for plants) suite was developed to computationally predict sites of RNA editing based on the well-known principle that editing in plant organelles increases the conservation of proteins across species. The PREP suite provides predictive RNA editors for plant mitochondrial genes (PREP-Mt), for chloroplast genes (PREP-Cp), and for alignments submitted by the user (PREP-Aln). These servers require minimal input, are very fast, and are highly accurate on all seed plants examined to date. PREP-Mt has proved useful in several research studies and the newly developed PREP-Cp and PREP-Aln servers should be of further assistance for analyses that require knowledge of the location of sites of RNA editing. The PREP suite is freely available at http://prep.unl.edu/.
Minimizing total respiratory heat loss is an important goal during mechanical ventilation. The aim of the present study was to evaluate whether changes in tracheal temperature (a clinical parameter that is easy to measure) are reliable indices of total respiratory heat loss in mechanically ventilated patients.
Total respiratory heat loss was measured, with three different methods of inspired gas conditioning, in 10 sedated patients. The study was randomized and of a crossover design. Each patient was ventilated for three consecutive 24-h periods with a heated humidifier (HH), a hydrophobic heat-moisture exchanger (HME) and a hygroscopic HME. Total respiratory heat loss and tracheal temperature were simultaneously obtained in each patient. Measurements were obtained during each 24-h study period after 45 min, and 6 and 24 h.
Total respiratory heat loss varied from 51 to 52 cal/min with the HH, from 100 to 108 cal/min with the hydrophobic HME, and from 92 to 102 cal/min with the hygroscopic HME (P < 0.01). Simultaneous measurements of maximal tracheal temperatures revealed no significant differences between the HH (35.7-35.9°C) and either HME (hydrophobic 35.3-35.4°C, hygroscopic 36.2-36.3°C).
In intensive care unit (ICU) mechanically ventilated patients, total respiratory heat loss was twice as much with either hydrophobic or hydroscopic HME than with the HH. This suggests that a much greater amount of heat was extracted from the respiratory tract by the HMEs than by the HH. Tracheal temperature, although simple to measure in ICU patients, does not appear to be a reliable estimate of total respiratory heat loss.
humidification of inspired gases; mechanical ventilation; total respiratory heat loss; tracheal temperature
Computing the edit distance between two genomes under certain operations is a basic problem in the study of genome evolution. The double-cut-and-join (DCJ) model has formed the basis for most algorithmic research on rearrangements over the last few years. The edit distance under the DCJ model can be easily computed for genomes without duplicate genes. In this paper, we study the edit distance for genomes with duplicate genes under a model that includes DCJ operations, insertions and deletions. We prove that computing the edit distance is equivalent to finding the optimal cycle decomposition of the corresponding adjacency graph, and give an approximation algorithm with an approximation ratio of 1.5 + ∈.
Trypanosome RNA editing is the posttranscriptional insertion and deletion of uridylate (U) residues, often to a massive extent, through cycles of cleavage, U addition or U removal, and ligation. These editing cycles are catalyzed by a complex that we purified to seven major proteins (bands I through VII). Here we analyze the role of band II using extracts of clonal band II RNA interference (RNAi) cell lines prepared by a rapid protocol that enables retention of activities that are lost during traditional extract preparation. By individually scoring each step of editing, we show that band II is critical for all steps of U insertion but is not important for any of the steps of U deletion or for their coordination into the U deletion cycle. This specificity supports the long- standing model that U-insertional and U-deletional activities are separated within the editing complex. Furthermore, by assaying the basic activities of the enzymes that catalyze the steps of U insertion, independent of their action in editing, we show that band II is not any of those enzymes. Rather, band II enables endonuclease action at authentic U insertion sites, terminal-uridylyl-transferase (TUTase) action at cleaved U insertion sites, and U-insertion-specific ligase (band V/IREL) action in the editing complex. Thus, band II facilitates each step of U insertion by providing proper RNA and/or protein recognition. We propose that band II (TbMP81) be called IRER, indicating its essential nature in U-insertional RNA editing recognition.