bluuebunny/crossref_metadata_2025_split huggingface dataset:
LSU rDNA‐BASED RFLP ASSAYS FOR DISCRIMINATING SPECIES AND STRAINS OF ALEXANDRIUM (DINOPHYCEAE)1
Authors: Scholin Christopher A. , Anderson Donald M. 
Published: October 2004

ABSTRACTIn a previous study large‐subunit ribosomal RNA gene (LSU rDNA) sequences from the marine dinoflagellates Alexandrium tamarense (Lebour) Balech, A. catenella (Whedon et Kofoid) Balech, A. fundyense Balech, A. affine (Fukuyo et Inoue) Balech, A. minutum Halim, A. lusitanicum Balech, and A. andersoni Balech were compared to assess inter‐ and intraspecific relationships. Many cultures compared in that study contained more than one class of LSU rDNA. Sequencing pooled clones of rDNA from single cultures revealed length heterogeneities and sequence ambiguities. This complicated sequence comparisons because multiple rDNA clones from a single culture had to be sequenced individually to document the different classes of molecules present in that culture. A further complication remained as to whether or not the observed intraculture sequence variations were reliable genetic markers or were instead artifacts of the polymerase chain reaction (PCR) amplification, cloning, and/or sequencing methods employed. The goals of the present study were to test the accuracy of Alexandrium LSU rDNA sequences using restriction fragment‐length polymorphism (RFLP) analysis and to devise RFLP‐based assays for discriminating among representatives of that group. Computer‐assisted examination of the sequences allowed us to identify a set of restriction enzymes that were predicted to reveal species, strain, and intraculture LSU rDNA heterogeneities. All groups identified by sequencing were revealed independently and repeatedly by RFLP analysis of PCR‐amplified material. Five ambiguities and one length heterogeneity, each of which ascribes a unique group of Alexandrium species or strains, were confirmed by restriction digests. Observed intraculture LSU rDNA heterogeneities were not artifacts of cloning and sequencing but were instead a good representation of the spectrum of molecules amplified during PCR reactions. Intraculture LSU rDNA heterogeneities thus serve as unique genetic markers for particular strains of Alexandrium, particularly those of A. tamarense, A. catenella, and A. fundyense. However, some of these “signature heterogeneities” represented a smaller portion of PCR product than was expected given acquired sequences. Other deviations from predicted RFLP patterns included incomplete digestions and appearance of spurious products. These observations indicate that the diversity of sequences in PCR product pools were greater than that observed by cloning and sequencing. The RFLP tests described here are useful tools for characterizing Alexandrium LSU rDNA to define the evolutionary lineage of cultures and are applicable at a fraction of the time, cost, and labor required for sequencing.
PHYSIOLOGICAL CHARACTERISTICS OF SPIRULINA PLATENSIS (CYANOBACTERIA) CULTURED AT ULTRAHIGH CELL DENSITIES1
Authors: Qiang Hu , Guterman Hugo , Richmond Amos 
Published: October 2004

ABSTRACTPhotosynthetic activity and growth physiology of Spirulina platensis (Nordstedt) Geitler cultures maintained at ultrahigh cell densities (i.e. above 100 mg chlorophyll‐L−1) in a newly designed photobioreactor were investigated. Nitrogen (NaNO3) in standard Zarouk medium was characterized as a major nutrient‐limiting factor in such cultures. The effect of ultrahigh cell density on photoinhibition of photosynthesis, as reflected by chlorophyll fluorescence and photosynthetic oxygen evolution, was studied: elevating the population density may arrest photoinhibition induced by high photon flux density, as well as low temperature. The relationship between incident irradiance and oxygen production rate was linear in situ for cultures at the optimal cell density, indicating that light limitation rather than light saturation or photoinhibition is the dominant condition outdoors in cultures of ultrahigh cell densities.In contrast with other reports, the extent of biomass loss at night due mainly to dark respiration was found to be relatively small when cell density was optimal, exerting only a minor effect on overall net productivity. Measurements of oxygen consumption at night revealed low rates of respiration, which may be explained by the low value of the volumetric mass transfer coefficient (KLa) of oxygen. Hence, reduced oxygen tension may play a role in preventing full expression of the respiratory potential in ultrahigh cell density cultures in which photoadaptive strategy may explain cell composition. Ultrahigh cell densities optimized with respect to the intensity of the light source, the length of the light path, and the extent of stirring represent the key for obtaining high output rates of cell mass and some natural products.
An infectious aetiology for childhood acute leukaemia: a review of the evidence
Authors: McNally Richard J. Q. , Eden Tim O. B. 
Published: October 2004

SummaryThere are three current hypotheses concerning infectious mechanisms in the aetiology of childhood leukaemia: exposure in utero or around the time of birth, delayed exposure beyond the first year of life to common infections and unusual population mixing. No specific virus has been definitively linked with childhood leukaemia and there is no evidence to date of viral genomic inclusions within leukaemic cells. The case–control and cohort studies have revealed equivocal results. Maternal infection during pregnancy has been linked with increased risk whilst breast feeding and day care attendance in the first year of life appear to be protective. There is inconclusive evidence from studies on early childhood infectious exposures, vaccination and social mixing. Some supportive evidence for an infectious aetiology is provided by the findings of space‐time clustering and seasonal variation. Spatial clustering suggests that higher incidence is confined to specific areas with increased levels of population mixing, particularly in previously isolated populations. Ecological studies have also shown excess incidence with higher population mixing. The marked childhood peak in resource‐rich countries and an increased incidence of the childhood peak in acute lymphoblastic leukaemia (ALL) (occurring at ages 2–6 years predominantly with precursor B‐cell ALL) is supportive of the concept that reduced early infection may play a role. Genetically determined individual response to infection may be critical in the proliferation of preleukaemic clones as evidenced by the human leucocyte antigen class II polymorphic variant association with precursor B‐cell and T‐cell ALL.
Possibilities for tailored and targeted therapy in paediatric acute myeloid leukaemia
Authors: Zwaan Ch. M. , Kaspers G. J. L. 
Published: October 2004

SummaryThe clinical outcome of acute myeloid leukaemia (AML) in children has improved considerably using intensive chemotherapy and/or stem cell transplantation. This leads to cure in 50–70% of patients, and also results in significant morbidity and mortality. Hence, we need other ways to improve the cure rate. This review discusses possibilities for tailored therapy, reviewing in vitro cellular drug sensitivity data. The results provide suggestions regarding the adaptation of clinical protocols in certain AML subgroups, although further clinical studies will show whether this is effective. Secondly, we review type 1 genetic abnormalities (such as receptor tyrosine kinase mutations) that result in enhanced survival and proliferation of leukaemic cells, which can be detected in approximately 50% of paediatric AML samples, and are non‐randomly associated with French–American–British type and cytogenetic subgroups. FLT3 internal tandem duplication is associated with poor clinical outcome, and may be used for risk‐group stratification. The first results with small molecule inhibitors in adult AML do not suggest their use in children as yet. International collaboration is needed to further improve outcome by developing treatment protocols for subgroups of paediatric AML.
Multiple myeloma involving central nervous system: high frequency of chromosome 17p13.1 (p53) deletions
Authors: Chang Hong , Sloan Stephen , Li Dan , Keith Stewart A. 
Published: October 2004

SummaryCentral nervous system (CNS) involvement is an unusual manifestation in multiple myeloma (MM). The molecular basis of CNS myeloma is poorly understood. MM is characterized by translocations involving the immunoglobulin heavy chain (IgH) locus and frequent 13q deletions. Alterations of p53 or c‐myc in MM may represent secondary changes associated with disease progression. We investigated nine patients with CNS MM using interphase fluorescence in situ hybridization (FISH) combined with immunofluorescence detection of the cytoplasmic light chain (cIg‐FISH) for the presence of above genomic aberrations. Of nine patients studied, eight cases had hemizygous p53 deletion and 4 had 13q deletions. Of the patients with 13q deletions, two had IgH translocations, one involving 4p16.3 (FGFR3), the other involving 16q23 (c‐maf). The high incidence of p53 deletions detected by cIg‐FISH in CNS myeloma may be a marker for chromosomal instability, and may be associated with metastatic features of myeloma cells.
Measuring T cell immunity to influenza vaccination in children after haemopoietic stem cell transplantation
Authors: Haining W. Nicholas , Evans John W. , Seth Nilufer P. , Callaway G. Derek , Wucherpfennig Kai W. , Nadler Lee M. , Guinan Eva C. 
Published: October 2004

SummaryQuantitative assessment of immunogen‐specific T cell responses may provide a meaningful surrogate marker of functional immunity in patients following haemopoietic stem cell transplantation (HSCT). We developed a flow‐cytometric assay to quantify antigen‐specific T cell immunity to influenza‐A and studied the T cell response to influenza vaccination in five children, 3–21 months post‐HSCT. All patients showed an increase in influenza‐A‐specific CD4+ immunity following vaccination while none had a detectable IgG response to the vaccine. This assay proved sufficiently sensitive to evaluate changes in T cell memory in immunocompromised individuals and could be used to better characterize post‐HSCT immune reconstitution.
A population study to define the incidence and survival of multiple myeloma in a National Health Service Region in UK
Authors: Phekoo K. J. , Schey S. A. , Richards M. A. , Bevan D. H. , Bell S. , Gillett D. , Møller H. ,   on behalf of Consultant Haematologists, South Thames Haematology Specialist Committee
Published: October 2004

SummaryEpidemiology data on multiple myeloma (MM) occurrence and outcome is inconsistent whilst a major limitation of randomized controlled trials is selection bias. We present a population‐based analysis of patients diagnosed with MM in the South Thames area, which comprises 5·4 million adult inhabitants. A total of 855 cases of MM were ascertained between 1999 and 2000 in a collaborative project involving haematologists and the Thames Cancer Registry. The age‐standardized rate was 3·29 per 100 000 and 4·82 cases per 100 000 (World Standard and European Population respectively). The median age was 73 years. The median survival for the whole group was 24 months whist it was 42 and 18 months in those aged less than 65 years and greater than 65 years respectively (P < 0·001). This population study has shown a higher incidence than previously reported in the UK and Europe and provides a benchmark for future studies. If survival is to be improved, future clinical trials and health care planning should consider patients over 65 years of age.
Synergistic epistasis and alternative hypotheses
Authors: Trouve S. , Ding A. , Goudet J. 
Published: October 2004

Abstract
Inbreeding generally results in deleterious shifts in mean fitness. If the fitness response to increasing inbreeding coefficient is non-linear, this suggests a contribution of epistasis to inbreeding depression. In a cross-breeding experiment, Salathé & Ebert (2003. J. Evol. Biol. 16: 976–985) tested and found the presence of this non-linearity in Daphnia magna. They argue that epistatic interactions cause this non-linearity. We argue here that their experimental protocol does not allow disentangling the effect of synergistic epistasis from two alternative hypotheses, namely hybrid vigour and statistical non-independence of data.
An experimental evaluation of self-interference in Narcissus assoanus: functional and evolutionary implications
Authors: Cesaro A. C. , Barrett S. C. H. , Maurice S. , Vaissiere B. E. , Thompson J. D. 
Published: October 2004

Abstract
Floral traits that reduce self-pollination in hermaphroditic plants have usually been interpreted as mechanisms that limit the genetic consequences of self-fertilization. However, the avoidance of sexual conflict between female and male function (self-interference) may also represent an important selection pressure for the evolution of floral traits, particularly in self-incompatible species. Here, we use experimental manipulations to investigate self-interference in Narcissus assoanus, a self-incompatible species with a stigma-height dimorphism in which the degree of spatial separation between sex organs (herkogamy) differs strikingly between the long- and short-styled morphs (hereafter L- and S-morphs). We predicted that weak herkogamy in the L-morph would cause greater self-pollination and hence self-interference. Experimental self-pollination reduced seed set when it occurred prior to, or simultaneously with, cross-pollination in the L-morph, but only if it occurred prior to cross-pollination in the S-morph. In the field, autonomous self-pollination was greater in the L-morph than the S-morph, but we found no evidence that self-interference reduced maternal or paternal fitness in either morph. One-day-old flowers of the L-morph have reduced stigma receptivity and hence exhibit protandry, whereas stigma receptivity and anther dehiscence are concurrent in the S-morph. This suggests that the two style morphs have alternative strategies for reducing self-interference: dichogamy in the L-morph and herkogamy in the S-morph. These results provide insight into the mechanisms that reduce sexual conflict in hermaphrodite plants and are of significance for understanding the evolution and maintenance of sexual polymorphisms.
Genetic and morphological data supporting the hypothesis of adaptive radiation in the endemic fish of Lake Matano
Authors: Roy D. , Docker M. F. , Hehanussa P. , Heath D. D. , Haffner G. D. 
Published: October 2004

Abstract
Adaptive radiation resulting from differential selection acting on functional features is believed to be an important source of biodiversity. In this study, morphometric measures and mitochondrial DNA are used to test for adaptive radiation within four fish genera (Glossogobius, Oryzias, Dermogenys and Telmatherina) endemic to an ancient island lake (Lake Matano, Sulawesi, Indonesia), using the framework proposed by Schluter (The Ecology of Adaptive Radiation, Oxford University Press, 2000). We demonstrate common ancestry and rapid divergence in one genus (Telmatherina) based on 560 bp of 16S sequence data. We found higher levels of variation in feeding-related traits (N = 8) for Telmatherina relative to the other genera, while no differences were found for sexual display traits (N = 8) or neutral morphological traits (N = 8). Telmatherina also had the highest number of distinct colouration patterns among the four genera. These data, combined with the very low productivity of the lake, are indicative of selection driving adaptive radiation. The morphometric divergence in the Telmatherina likely results from selection acting on feeding traits in this low productivity lake, leading to trophic specialization among closely related morphotypes. These results provide indirect but compelling data supporting the adaptive radiation of Telmatherina in this system.
Evidence for epistasis: reply to Trouve et al.
Authors: Ebert D. , Salathé P. , Kawecki T. J. 
Published: October 2004

Abstract
Salathé and Ebert (2003, J. Evol. Biol. 16: 976–985) have shown that the mean logarithmic fitness of Daphnia magna clones declined faster than linearly with increasing inbreeding coefficient F. They interpreted this result as evidence for synergistic epistasis. Trouve et al. (2004, J. Evol. Biol., doi: 10.1111/j.1420-9101.2004.00755.x) suggested that hybrid vigour could be an alternative explanation for this finding. We use a population genetic model to support the original claim that the marked deviation from linearity cannot be explained without epistasis. We further argue that the relevant reference population is the metapopulation and not the subpopulation. Taken together, we believe that synergistic epistasis between recessive deleterious alleles segregating in the D. magna metapopulation is the most likely explanation for the finding of Salathé and Ebert.
Careful physical examination is essential in the preoperative assessment of children for dental extractions under general anesthesia
Authors: Rutherford John , Stevenson Ruth 
Published: October 2004

SummaryBackground : Physical examination is routinely carried out for the preoperative assessment of children, but is it of value in day stay community dental surgery?Methods : A prospective survey of new diagnoses made on children presenting for community dental extractions and compared with children having nondental surgery.Results : Five of 216 children for dental extractions were seen with new diagnoses made, with a variety of conditions including patent ductus arteriosus, aortic stenosis, ventricular septal defect and obstructive sleep apnea. No new diagnoses were made in 294 nondental children in the same period.Conclusions : Physical examination provides a useful adjunct to the history in children undergoing community dental extraction. There is potentially significant morbidity undiagnosed in apparently fit children presenting for dental surgery.
Vertical infraclavicular brachial plexus block in children: a preliminary study
Authors: de Jose Maria Belen , Tielens Luc K.P. 
Published: October 2004

SummaryBackground : Brachial plexus blockade is a well‐established technique in upper limb surgery. Among the infraclavicular approaches, the vertical infraclavicular brachial plexus (VIP) block is easy to perform and has a large spectrum of nerve blockade. The aim of this preliminary study was to determine the ease, effectiveness, safety, and duration of the VIP block in pediatric trauma surgery.Methods : Fifty‐five patients (ASA physical status I and II, age range 5–17 years old) scheduled for upper limb trauma surgery received a VIP block under light general anesthesia, using 0.5 ml·kg−1 of ropivacaine 0.5%. The number of attempts and time to perform the block, the occurrence of a surgical response, the visual analogue score (VAS) scores, the incidence of complications and the duration of the block were evaluated.Results : The brachial plexus was found easily at the first or second attempt in 85% (47 of 55) of the cases, in 15% (eight of 55) of the cases it was localized after three to four attempts. The mean time to perform the block was 3.35 ± 3.37 min. Ninety‐eight percentage (54 of 55) of the blockades were effective for surgery and in just one case was ineffective. The VAS scores at the end of the procedure in 100% (55 of 55) of the cases were <3. There were no cases with clinical signs of pneumothorax nor inadvertent puncture of major vessels. Two patients developed a Horner's syndrome and in one a mild superficial hematoma at the puncture site occurred. The mean sensory block duration was 8.45 ± 1.71 h and the mean motor block duration was 6.52 ± 2.50 h.Conclusions : In this preliminary study, the VIP block was easy to perform, effective and free of major complications for pediatric trauma surgery. With the doses of ropivacaine we used it was useful for intra‐ and postoperative analgesia.
Herbal medicine use by children presenting for ambulatory anesthesia and surgery
Authors: Crowe Suzanne , Lyons Barry 
Published: October 2004

SummaryBackground : Herbal medicine use has become increasingly popular throughout the world. Some of these agents may have serious interactions with anesthetic drugs. Children may potentially be more vulnerable to such interactions because of altered drug handling. While the prevalence of herbal medicine use by children with some chronic illnesses has been estimated, the incidence of this in a population of otherwise healthy children admitted for minor ambulatory anesthesia and surgery is currently unknown.Methods : Parents of 601 children presenting consecutively for ambulatory surgery were asked to complete a questionnaire detailing administration of herbal medicines to their child.Results : This study identified that 6.4% of children were currently taking an herbal preparation; while a further 10.1% had taken an herbal medicine in the past. Echinacea and arnica were the commonest used herbal remedies. A significant number of children had taken agents which may interact with anesthesia and surgery: St John's Wort, valerian, garlic and gingko. Information on herbal medicines was mostly obtained by parents from nonmedical sources.Conclusions : A total of 16.6% of children had a current or past history of ingestion of herbal medicines. This finding may have implications for the perioperative management of children presenting for day‐case surgery.
Use of a remifentanil–propofol mixture for pediatric flexible fiberoptic bronchoscopy sedation
Authors: Berkenbosch John W. , Graff Gavin R. , Stark James M. , Ner Zarah , Tobias Joseph D. 
Published: October 2004

SummaryBackground : Flexible fiberoptic bronchoscopy is an important diagnostic tool for pediatric pulmonologists. Because of its favorable respiratory profile, ketamine has become a popular sedative for this procedure, but may be associated with unpleasant emergence reactions in the older child. Remifentanil is a newer, ultra‐short acting opioid that has been shown to provide effective sedation and cough suppression for fiberoptic bronchoscopy when combined with intermittent propofol boluses. However, delivery of these agents as a combined, single infusion has not been described.Methods : Children ≥2 years of age undergoing fiberoptic bronchoscopy were enrolled. Remifentanil was mixed in a single syringe with undiluted propofol giving final drug concentrations of 10 mg·ml−1 of propofol and 15–20 μg·ml−1 of remifentanil. Sedation was induced with a bolus of approximately 0.1 ml·kg−1 of this mixture and maintained by titrating the drip throughout the procedure. Vital signs, sedative effectiveness, recovery patterns, and complications were prospectively recorded.Results : Fifteen patients aged 9.0 ± 5.3 years were sedated. Sedation was induced with 1.2 ± 0.4 mg·kg−1 propofol (2.4 ± 0.8 μg·kg−1 remifentanil) and maintained with 4.1 ± 1.8 mg·kg−1·h−1 propofol (0.13 ± 0.06 μg·kg−1·min−1 remifentanil). Five patients received low‐dose ketamine to augment sedation. The maximal decrease in respiratory rate was 6.1 ± 5.3 b·min−1 (27.6 ± 21%) and no patient became hypoxemic. All procedures were completed easily without significant complication. Patients recovered to baseline 13.3 ± 8.5 min following infusion discontinuation.Conclusions : A remifentanil/propofol mixture provided effective sedation and rapid recovery in pediatric patients undergoing fiberoptic bronchoscopy.