bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of Norovirus Capsid Protein in Authentic Standards and in Stool Extracts by Matrix-Assisted Laser Desorption Ionization and Nanospray Mass Spectrometry
Authors: Colquhoun David R. , Schwab Kellogg J. , Cole Robert N. , Halden Rolf U.
Published: April 2006

Mass spectrometry (MS) represents a rapid technique for the identification of microbial monocultures, and its adaptation to the detection of pathogens in real-world samples is a public health and homeland security priority. Norovirus, a leading cause of gastroenteritis in the world, is difficult to monitor because it cannot be cultured outside the human body. The detection of norovirus capsid protein was explored using three common MS-based methods: scanning of intact proteins, peptide mass fingerprinting, and peptide sequencing. Detection of intact target protein was limited by poor selectivity and sensitivity. Detection of up to 16 target peptides by peptide mass fingerprinting allowed for the reproducible and confident (
P
< 0.05) detection of the 56-kDa norovirus capsid protein in the range of 0.1 × 10
−12
to 50 × 10
−12
mol in authentic standards of recombinant norovirus virus-like particles (VLPs). To explore assay performance in complex matrixes, a non-gel-based, rapid method (2 to 3 h) for virus extraction from human stool was evaluated (72% ± 12% recovery), and additional analyses were performed on norovirus-free stool extracts fortified with VLPs. Whereas peptide mass fingerprinting was rendered impractical by sample interferences, peptide sequencing using nanospray tandem MS facilitated unambiguous identification of ≥250 fmol of capsid protein in stool extracts. This is the first report on MS-based detection of norovirus, accomplished by using structurally identical, noninfective VLPs at clinically relevant concentrations. It represents an important milestone in the development of assays for surveillance of this category B bioterrorism agent.
Lipid II-Based Antimicrobial Activity of the Lantibiotic Plantaricin C
Authors: Wiedemann Imke , Böttiger Tim , Bonelli Raquel Regina , Schneider Tanja , Sahl Hans-Georg , Martínez Beatriz
Published: April 2006

We analyzed the mode of action of the lantibiotic plantaricin C (PlnC), produced by
Lactobacillus plantarum
LL441. Compared to the well-characterized type A lantibiotic nisin and type B lantibiotic mersacidin, which are both able to interact with the cell wall precursor lipid II, PlnC displays structural features of both prototypes. In this regard, we found that lipid II plays a key role in the antimicrobial activity of PlnC besides that of pore formation. The pore forming activity of PlnC in whole cells was prevented by shielding lipid II on the cell surface. However, in contrast to nisin, PlnC was not able to permeabilize
Lactococcus lactis
cells or to form pores in 1,2-dioleoyl-
sn
-glycero-3-phosphocholine liposomes supplemented with 0.1 mol% purified lipid II. This emphasized the different requirements of these lantibiotics for pore formation. Using cell wall synthesis assays, we identified PlnC as a potent inhibitor of (i) lipid II synthesis and (ii) the FemX reaction, i.e., the addition of the first Gly to the pentapeptide side chain of lipid II. As revealed by thin-layer chromatography, both reactions were clearly blocked by the formation of a PlnC-lipid I and/or PlnC-lipid II complex. On the basis of the in vivo and in vitro activities of PlnC shown in this study and the structural lipid II binding motifs described for other lantibiotics, the specific interaction of PlnC with lipid II is discussed.
Bacillus
Endospores Isolated from Granite: Close Molecular Relationships to Globally Distributed
Bacillus
spp. from Endolithic and Extreme Environments
Authors: Fajardo-Cavazos Patricia , Nicholson Wayne
Published: April 2006

As part of an ongoing effort to catalog spore-forming bacterial populations in environments conducive to interplanetary transfer by natural impacts or by human spaceflight activities, spores of
Bacillus
spp. were isolated and characterized from the interior of near-subsurface granite rock collected from the Santa Catalina Mountains, AZ. Granite was found to contain ∼500 cultivable
Bacillus
spores and ∼10
4
total cultivable bacteria per gram. Many of the
Bacillus
isolates produced a previously unreported diffusible blue fluorescent compound. Two strains of eight tested exhibited increased spore UV resistance relative to a standard
Bacillus subtilis
UV biodosimetry strain. Fifty-six isolates were identified by repetitive extragenic palindromic PCR (rep-PCR) and 16S rRNA gene analysis as most closely related to
B. megaterium
(15 isolates),
B. simplex
(23 isolates),
B. drentensis
(6 isolates),
B. niacini
(7 isolates), and, likely, a new species related to
B. barbaricus
(5 isolates). Granite isolates were very closely related to a limited number of
Bacillus
spp. previously found to inhabit (i) globally distributed endolithic sites such as biodeteriorated murals, stone tombs, underground caverns, and rock concretions and (ii) extreme environments such as Antarctic soils, deep sea floor sediments, and spacecraft assembly facilities. Thus, it appears that the occurrence of
Bacillus
spp. in endolithic or extreme environments is not accidental but that these environments create unique niches excluding most
Bacillus
spp. but to which a limited number of
Bacillus
spp. are specifically adapted.
Planktonic Replication Is Essential for Biofilm Formation byLegionella pneumophilain a Complex Medium under Static and Dynamic Flow Conditions
Authors: Mampel Jörg , Spirig Thomas , Weber Stefan S. , Haagensen Janus A. J. , Molin Søren , Hilbi Hubert
Published: April 2006

Legionella pneumophilapersists for a long time in aquatic habitats, where the bacteria associate with biofilms and replicate within protozoan predators. WhileL. pneumophilaserves as a paradigm for intracellular growth within protozoa, it is less clear whether the bacteria form or replicate within biofilms in the absence of protozoa. In this study, we analyzed surface adherence of and biofilm formation byL. pneumophilain a rich medium that supported axenic replication. Biofilm formation by the virulentL. pneumophilastrain JR32 and by clinical and environmental isolates was analyzed by confocal microscopy and crystal violet staining. Strain JR32 formed biofilms on glass surfaces and upright polystyrene wells, as well as on pins of “inverse” microtiter plates, indicating that biofilm formation was not simply due to sedimentation of the bacteria. Biofilm formation by anL. pneumophila fliAmutant lacking the alternative sigma factor σ28was reduced, which demonstrated that bacterial factors are required. Accumulation of biomass coincided with an increase in the optical density at 600 nm and ceased when the bacteria reached the stationary growth phase.L. pneumophilaneither grew nor formed biofilms in the inverse system if the medium was exchanged twice a day. However, after addition ofAcanthamoeba castellanii, the bacteria proliferated and adhered to surfaces. Sessile (surface-attached) and planktonic (free-swimming)L. pneumophilaexpressed β-galactosidase activity to similar extents, and therefore, the observed lack of proliferation of surface-attached bacteria was not due to impaired protein synthesis or metabolic activity. Cocultivation of green fluorescent protein (GFP)- and DsRed-labeledL. pneumophilaled to randomly interspersed cells on the substratum and in aggregates, and no sizeable patches of clonally growing bacteria were observed. Our findings indicate that biofilm formation byL. pneumophilain a rich medium is due to growth of planktonic bacteria rather than to growth of sessile bacteria. In agreement with this conclusion, GFP-labeledL. pneumophilainitially adhered in a continuous-flow chamber system but detached over time; the detachment correlated with the flow rate, and there was no accumulation of biomass. Under these conditions,L. pneumophilapersisted in biofilms formed byEmpedobacter breveorMicrobacteriumsp. but not in biofilms formed byKlebsiella pneumoniaeor other environmental bacteria, suggesting that specific interactions between the bacteria modulate adherence.
Diversity and Biocatalytic Potential of Epoxide Hydrolases Identified by Genome Analysis
Authors: van Loo Bert , Kingma Jaap , Arand Michael , Wubbolts Marcel G. , Janssen Dick B.
Published: April 2006

Epoxide hydrolases play an important role in the biodegradation of organic compounds and are potentially useful in enantioselective biocatalysis. An analysis of various genomic databases revealed that about 20% of sequenced organisms contain one or more putative epoxide hydrolase genes. They were found in all domains of life, and many fungi and actinobacteria contain several putative epoxide hydrolase-encoding genes. Multiple sequence alignments of epoxide hydrolases with other known and putative α/β-hydrolase fold enzymes that possess a nucleophilic aspartate revealed that these enzymes can be classified into eight phylogenetic groups that all contain putative epoxide hydrolases. To determine their catalytic activities, 10 putative bacterial epoxide hydrolase genes and 2 known bacterial epoxide hydrolase genes were cloned and overexpressed in
Escherichia coli
. The production of active enzyme was strongly improved by fusion to the maltose binding protein (MalE), which prevented inclusion body formation and facilitated protein purification. Eight of the 12 fusion proteins were active toward one or more of the 21 epoxides that were tested, and they converted both terminal and nonterminal epoxides. Four of the new epoxide hydrolases showed an uncommon enantiopreference for
meso
-epoxides and/or terminal aromatic epoxides, which made them suitable for the production of enantiopure (
S
,
S
)-diols and (
R
)-epoxides. The results show that the expression of epoxide hydrolase genes that are detected by analyses of genomic databases is a useful strategy for obtaining new biocatalysts.
Molecular Epidemiology of Norovirus in Outbreaks of Gastroenteritis in Southwest Germany from 2001 to 2004
Authors: Ike Anthony C. , Brockmann Stefan O. , Hartelt Kathrin , Marschang Rachel E. , Contzen Matthias , Oehme Rainer M.
Published: April 2006

The identification and molecular epidemiology of norovirus in outbreaks of gastroenteritis were studied during a 3-year period in Germany. Specimens (
n
= 316) from 159 nonbacterial gastroenteritis outbreaks from March 2001 to June 2004 were analyzed for the presence of noroviruses by reverse transcriptase PCR. Outbreaks were most frequent in elderly people's homes and care centers (43%), followed by hospitals (24%). Molecular analyses of strains from 148 outbreaks showed that there were up to 12 genotypes involved in the outbreaks. Genogroup II noroviruses were responsible for 95% of the outbreaks. Cocirculation of more than one strain in the same outbreak and cocirculation of genogroup I and II strains in the same place were observed. Genogroup II4 (Grimsby-like) was the most prevalent strain, accounting for 48% and 67% of the outbreaks in 2002 and 2003, respectively. The genogroup IIb (Castell/Suria) genotype was observed in all the years of the study. Epidemiological and molecular data indicated that there was a major shift of the predominant strain that coincided with the appearance of a new variant of genogroup II4 in 2002. By the application of reverse transcriptase PCR, this study has demonstrated the importance and dynamism of noroviruses in Germany.
Genotyping of
Toxoplasma gondii
by Multiplex PCR and Peptide-Based Serological Testing of Samples from Infants in Poland Diagnosed with Congenital Toxoplasmosis
Authors: Nowakowska Dorota , Colón Iris , Remington Jack S. , Grigg Michael , Golab Elzbieta , Wilczynski J. , Sibley L. David
Published: April 2006

Toxoplasma gondii
has a clonal population genetic structure with three (I, II, and III) lineages that predominate in North America and Europe. Type II strains cause most cases of symptomatic human infections in France and the United States, although few other regions have been adequately sampled. Here we determined the parasite genotype in amniotic fluid and cerebrospinal fluid samples from congenital toxoplasmosis cases in Poland. Nineteen confirmed congenital cases of toxoplasmosis were analyzed, including both severe and asymptomatic cases. The genotype of parasite strains causing congenital infection was determined by direct PCR amplification and restriction fragment length polymorphism analysis. Nested multiplex PCR analysis was used to type four independent polymorphic markers. The sensitivity of multiplex nested PCR was ≥25 parasites/ml in amniotic fluid and cerebral spinal fluid samples. Parasite DNA was successfully amplified in 9 of 19 samples (eight severely affected and one asymptomatic fetus). Only genotype II parasites were identified as the source of
T. gondii
infection based on restriction fragment length polymorphism analysis. Strains causing congenital infections were also typed indirectly based on detection of antibodies to strain-specific peptides. Serotyping indicated that 12 of 15 cases tested were caused by type II strains and these positives included both symptomatic and asymptomatic infections. Overall, the combined analysis indicated that 14 of the cases were caused by type II strains. Our results are consistent with the hypothesis that parasite burden is associated with severity of congenital toxoplasmosis and indicate that serological testing provides a promising method for genotypic analysis of toxoplasmosis.
Isothermal Amplification and Molecular Typing of the Obligate Intracellular Pathogen
Mycobacterium leprae
Isolated from Tissues of Unknown Origins
Authors: Groathouse Nathan A. , Brown Susan E. , Knudson Dennis L. , Brennan Patrick J. , Slayden Richard A.
Published: April 2006

Molecular diagnostic and epidemiology studies require appreciable amounts of high-quality DNA. Molecular epidemiologic methods have not been routinely applied to the obligate intracellular organism
Mycobacterium leprae
because of the difficulty of obtaining a genomic DNA template from clinical material. Accordingly, we have developed a method based on isothermic multiple-displacement amplification to allow access to a high-quality DNA template. In the study described in this report, we evaluated the usefulness of this method for error-sensitive, multiple-feature molecular analyses. Using test samples isolated from lepromatous tissue, we also evaluated amplification fidelity, genome coverage, and regional amplification bias. The fidelity of amplified genomic material was unaltered; and while regional differences in global amplification efficiency were seen by using comparative microarray analysis, a high degree of concordance of amplified genomic DNA was observed. This method was also applied directly to archived tissue specimens from leprosy patients for the purpose of molecular typing by using short tandem repeats; the success rate was increased from 25% to 92% without the introduction of errors. This is the first study to demonstrate that serial whole-genome amplification can be coupled with error-sensitive molecular typing methods with low-copy-number sequences from tissues containing an obligate intracellular pathogen.
Multiple-Locus Variable-Number Tandem Repeat Analysis of
Neisseria meningitidis
Yields Groupings Similar to Those Obtained by Multilocus Sequence Typing
Authors: Schouls Leo M. , van der Ende Arie , Damen Marjolein , van de Pol Ingrid
Published: April 2006

We identified many variable-number tandem repeat (VNTR) loci in the genomes of
Neisseria meningitidis
serogroups A, B, and C and utilized a number of these loci to develop a multiple-locus variable-number tandem repeat analysis (MLVA). Eighty-five
N. meningitidis
serogroup B and C isolates obtained from Dutch patients with invasive meningococcal disease and seven reference strains were analyzed using MLVA and multilocus sequence typing (MLST). MLVA, based on eight VNTR loci with limited variability in the number of repeats, yielded clustering of the strains similar to that obtained by MLST, with congruence between both methods amounting to 69%. The ability to recognize clonal complexes makes MLVA a valuable high-throughput method to serve as a tool complementary to MLST. Four highly variable VNTR loci were used in a second assay to analyze
N. meningitidis
serogroup C strains collected during an outbreak of meningococcal disease in The Netherlands. Typing based on the latter VNTR loci enabled differentiation of isolates with identical MLST sequence types and grouped epidemiologically related strains.
Invasive
Haemophilus influenzae
in Manitoba, Canada, in the Postvaccination Era
Authors: Tsang Raymond S. W. , Mubareka Samira , Sill Michelle L. , Wylie John , Skinner Stuart , Law Dennis K. S.
Published: April 2006

Fifty-two
Haemophilus influenzae
isolates from patients with invasive disease in the province of Manitoba, Canada, were examined for serotype, biotype, genotype, and antibiotic susceptibility. Half of the 52 isolates were found to be serotype a, and 38.5% (20 isolates) were found to be nonserotypeable (NST). There were only three serotype b strains and one each for serotypes c, d, and f. All 26 serotype a isolates belonged to biotype II and demonstrated identical or highly similar DNA fingerprints by pulsed-field gel electrophoresis. An analysis of these isolates by multilocus sequence typing showed that they belong to the clonal complex ST-23. While 69% (18 of 26) of the serotype a cases were found in males, only 9 (45%) of the 20 patients with NST isolates were males. Twenty (77%) of the 26 serotype a isolates were from patients who were ≤24 months old. Twelve (63%) of the NST isolates were from adult or adolescent patients. In contrast to the clonal nature of serotype a isolates, the 20 NST isolates were found to belong to 18 different sequence types. Most of these 18 different sequence types were unrelated to each other, with the exception of 7 sequence types grouped into three clonal groups. Two (6.25%) out of 32 serotypeable isolates (1 serotype a and 1 serotype b) and 6 (30%) of 20 NST isolates were resistant to ampicillin due to β-lactamase production. These results suggest a change in the epidemiology of
H. influenzae
disease, with the majority of invasive
H. influenzae
isolates being associated with serotype a and NST strains.
Rapid Identification of
Enterococcus hirae
and
Enterococcus durans
by PCR and Detection of a Homologue of the
E. hirae mur-2
Gene in
E. durans
Authors: Arias Cesar A. , Robredo Beatriz , Singh Kavindra V. , Torres Carmen , Panesso Diana , Murray Barbara E.
Published: April 2006

During an evaluation of PCR for identification of isolates of
Enterococcus hirae
, a homologue with 82% identity to
E. hirae mur-2
was identified in
Enterococcus durans
and was named
mur-2
ed
. PCR using primers for two genes (
copY
and
murG
) of
E. hirae
strains showed amplification with
E. hirae
strains only. PCR (under high-stringency conditions) with primers for the
mur-2
ed
gene gave the expected amplification product only with
E. durans
strains. A combination of
murG
and

mur-2
ed

primers in a multiplex PCR assay differentiated
E. hirae
from
E. durans
in all cases. PCR using these primers appears to be a rapid alternative for identification of
E. hirae
and
E. durans
isolates.
Evaluation of Diagnostic Assays for Hepatitis E Virus in Outbreak Settings
Authors: Myint Khin Saw Aye , Endy Timothy P. , Gibbons Robert V. , Laras Kanti , Mammen Mammen P. , Sedyaningsih Endang R. , Seriwatana Jitvimol , Glass Jonathan S. , Narupiti Sumitda , Corwin Andrew L.
Published: April 2006

Hepatitis E virus (HEV) is a major cause of hepatitis. We evaluated five HEV antibody diagnostic assays by using outbreak specimens. The Abbott immunoglobulin G (IgG), Genelabs IgG, and Walter Reed Army Institute of Research (WRAIR) IgM assays were about 90% sensitive; the Abbott IgG and WRAIR total Ig and IgM assays were more than 90% specific.
Nosocomial Bacteremia Due to an As Yet Unclassified
Acinetobacter
Genomic Species 17-Like Strain
Authors: Rodriguez-Baño Jesús , Martí Sara , Ribera Anna , Fernández-Cuenca Felipe , Dijkshoorn Lenie , Nemec Alexandr , Pujol Miquel , Vila Jordi
Published: April 2006

We describe a case of bacteremia due to an as yet unclassified
Acinetobacter
genomic species 17-like strain. The recognition of this microorganism as non-
Acinetobacter baumannii
may have important epidemiological implications, as it relieves the hospital of the implementation of barrier precautions for patients infected or colonized as may be necessary with a multiresistant
A. baumannii
epidemic.
Selective Protection of 1,4,8,11-Tetraazacyclotetradecane (Cyclam) in Position 1,4 with the Phosphonothioyl Group and Synthesis of a Cyclam-1,4-bis(methylphosphonic Acid). Crystal Structures of Several Cyclic Phosphonothioamides
Authors: Vitha Tomáš , Kotek Jan , Rudovský Jakub , Kubíček Vojtěch , Císařová Ivana , Hermann Petr , Lukeš Ivan
Published: April 2006

A new cyclam-based ligand, 1,4,8,11-tetraazacyclotetradecane-1,4-bis(methylphosphonic acid) (1,4-H4te2p), was synthesized. Cyclam was protected by the reaction with PhP(S)Cl2 to form exclusively five-membered cyclic phenylphosphonothioic diamide 2 in a moderate yield. The solid-state structures of 2 and several by-products were determined. Compound 2 was isolated as two stable conformers differing in a mutual position of benzene ring and sulfur atom with respect to the cyclam ring. Compound 2 was used for the synthesis of 1,4-dibenzylcyclam. However, the deprotection of the thiophosphoryl-protected bis(methylphosphonate diester) with aqueous HCl under non-optimized conditions led to a mixture of cyclam derivatives differently substituted with methylphosphonic acid groups. The crystal structures of the target product, 1,4-H4te2p, and also 1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetrakis(methylphosphonic acid) (H8tetp) were determined. A similar reaction with cyclen (1,4,7,10-tetraazacyclododecane) led only to hardly purifiable mixtures.
Young people and work injuries: an examination of jurisdictional variation within Canada
Authors: Breslin F C , Smith P , Mustard C , Zhao R
Published: April 2006

Objective:The purpose of this study was to identify risk factors of work injuries among Canadian adolescents and young adults and to examine provincial differences in work injury rates.

Methods:Information on work and injuries were obtained from a representative sample of 14 541 Canadians aged 15–24 years. Respondents reported medically attended, work related injuries in the past 12 months, work hours, and type of occupation. A multivariate logistic regression on likelihood of work injury included demographic and work variables, as well as province of residence.

Results:Even when factors expected to vary by province such as occupation were statistically controlled, Saskatchewan youth were about twice as likely to be injured at work compared to Ontario youth. Type of job was a major correlate of injury risk, with all jobs showing higher risk than administrative clerical jobs. Even with type of job controlled, visible minorities, students, and 15–17 year olds had a reduced likelihood of work injury than their counterparts.

Conclusions:Many young Canadians sustain work injuries that have clear medical costs and potential long term health consequences. Individual level explanations for youth’s increased risk for workplace injuries (for example, inexperience or developmental factors) need to be supplemented with a better understanding of the broader social, economic, and political factors across jurisdictions.
Child passenger safety for inner-city Latinos: new approaches from the community
Authors: Martin M , Holden J , Chen Z , Quinlan K
Published: April 2006

Objective:Motor vehicle crashes injuries, the leading cause of death for Latino children in the United States, can be reduced by the correct use of child safety seats. This study evaluated the ability of a community health worker education program to improve proper child safety seat usage in urban low income Latino families.

Methods:At a series of check events, proper child safety seat usage in families who had received an education intervention was compared with similar families who had not. The education intervention, provided by Latino community health workers trained as child passenger safety technicians, used videos and an office demonstrator. Members of the target community initiated the study and participated in its subsequent design and implementation.

Results:The families that participated in the study were primarily Mexican with low income, education, and acculturation levels. Forty six rear facing and 44 forward facing child safety seats were checked. Families exposed to the intervention were more likely to have their child’s seat within the manufacturer’s recommended weight/height range, their child facing the correct direction, the harness straps positioned properly, to have not been in a crash, the harness straps snug, the harness retainer clip used correctly, the seat belt routed correctly, and the seat belt locked.

Conclusions:Exposure to an educational intervention provided by community health workers trained as child passenger safety technicians was associated with child safety seats being used more properly than seats of families not exposed to the intervention in an urban low income Latino community.
Passenger seating position and the risk of passenger death in traffic crashes: a matched cohort study
Authors: Smith K M , Cummings P
Published: April 2006

Objective:To estimate the association of passenger seating position with the risk of death for passengers in traffic crashes.

Design, setting, participants:Matched cohort analysis of data from the National Highway Traffic Safety Administration Fatality Analysis Reporting System regarding 56 644 passengers in 23 308 passenger cars, light trucks, vans, and sport utility vehicles that crashed during 1990–2001.

Main outcome measure:The adjusted risk ratio (aRR) for death of a rear seat passenger compared with a front seat passenger within 30 days of a crash.

Results:The aRR for all passengers in the rear seat in a crash was 0.79 (95% CI 0.77 to 0.82). This estimate varied by age, restraint use, and the presence of a front passenger airbag (p<0.001). For restrained passengers in cars with a front passenger airbag, the aRR was 0.62 (95% CI 0.48 to 0.81) for children 0–12 years, 0.96 (95% CI 0.88 to 1.06) for passengers 13–29 years, 1.03 (95% CI 0.93 to 1.15) for passengers 30–59 years, and 1.06 (95% CI 0.90 to 1.26) for passengers 60 years or older. The rear seat was associated with more protection in cars without front airbags and more protection for unrestrained passengers compared with restrained passengers.

Conclusions:Previous studies have reported that the rear seat was safer for persons of all ages; thus seating a young child in the rear has often meant that older children and adults had to assume an increased risk of death by sitting in the front. These results suggest that when front passenger airbags are present and passengers are restrained, putting adults in front and children in back enhances child safety without sacrificing adult safety.
A prospective cohort study of health outcomes following whiplash associated disorders in an Australian population
Authors: Rebbeck T , Sindhusake D , Cameron I D , Rubin G , Feyer A-M , Walsh J , Gold M , Schofield W N
Published: April 2006

Objective:To define health outcomes of whiplash associated disorders (WAD) at three months, six months, and two years after injury and to examine predictors of these outcomes.

Design:Prospective cohort study.

Setting:New South Wales, Australia.

Subjects:People with compensable motor crash injuries who reported whiplash as one of their injuries.

Interventions:None.

Main outcome measures:Functional Rating Index (FRI), Short Form 36 (SF-36) at three months, six months, and two years after injury, ascertained by telephone interview.

Results:At three months, 33.6% of the cohort was recovered (as defined by FRI⩽25), increasing marginally at six months (38.9% recovered), but more significantly at two years (51.7% recovered, p = 0.001). The mean physical component score of the SF-36 improved at each time point (p = 0.002), while the mean mental component score did not (p = 0.59). Predictors of recovery at two years (as defined by global perceived effect) included a lower FRI index at baseline (p = 0.001) and closure of the claim at two years (p = 0.02).

Conclusion:Whiplash injury had a large effect on the health of this Australian cohort of whiplash sufferers, with only 50% of the cohort recovered at two years. Physical measures of health appear to improve over time, whereas mental measures of health did not. Despite this, this cohort is largely able to participate in activities and work at two years. Prevention of chronic disability may lie with concentration of resources to those who score highly on the FRI at baseline. In addition, chronic psychological ill health may be prevented by directing treatment to those with poor scores on sensitive measures of psychological ill health at baseline.
The spectrum of intoxication and poisonings among adolescents: surveillance in an urban population
Authors: Cheng T L , Wright J L , Pearson-Fields A S , Brenner R A
Published: April 2006

Aim:Among adolescents, poisoning is a leading cause of injury mortality in the United States. This study describes the epidemiology of poisonings, intoxication, and maladaptive effects of drugs among adolescents age 10–19 years in a large city.

Methods:An injury surveillance system used records at seven hospitals, medical examiner records, and vital records over a two year period.

Results:Of 633 cases (618 injuries/100 000/year), 6% were unintentional, 36% self-inflicted, 41% alcohol intoxication, and 15% maladaptive effects of drugs. Alcohol was involved in 45% of cases, 23% illegal drugs, 23% non-prescription drugs, 19% prescription drugs; 19% involved more than one substance. Hospitalization was required in 20%; 8% transferred to another hospital; one died from intoxication. The authors found high rates of self-inflicted poisoning, intoxication, and maladaptive effects of drugs among this urban population.

Conclusion:The study highlights the need to broadly define poisonings among adolescents and the challenge of assessing intent in some cases.
Road traffic casualties: understanding the night-time death toll
Authors: Plainis S , Murray I J , Pallikaris I G
Published: April 2006

A disproportionate number of fatal injuries occur after dark. The paper presents some statistics of road traffic injuries in a novel way which suggests that low luminance plays a major role in this effect. A sound physiological explanation for this is advanced based on the poor temporal characteristics of rod photoreceptors. It is argued that processing information based on low luminance, low contrast targets is much slower than that for high contrast bright targets. To test the idea, simple visual reaction times were measured under typical low visibility conditions encountered on non-lit roads and were found to be substantially longer than under optimal conditions. It is shown that longer reaction times translate into significantly increased stopping distances. This important point has received insufficient attention in the road safety literature, by the Highways Agency, the police, injury prevention officials, and the UK Highway Code.
Associations between risk behavior and injury and the protective roles of social environments: an analysis of 7235 Canadian school children
Authors: Pickett W , Dostaler S , Craig W , Janssen I , Simpson K , Shelley S Danielle , Boyce W F
Published: April 2006

Objective:The social etiology of adolescent injury remains poorly understood. ThePopulation Health Frameworksuggests that the etiology of adolescent injury involves interactions between individual risk factors and the natures of adolescent environments. The purpose of this study was to apply this framework to examination of relationships between adolescent risk taking and injury, and the potential modifying effects of supportive home and school environments.

Methods:The analysis was conducted in a representative sample of 7235 males and females (10–16 years old) from Canada. Results were based on records from the 2001/02 World Health OrganizationHealth Behaviour in School-Aged Children Survey. Individual items and factor analytically derived scales were used to describe and then model injury outcomes, risk behaviors, perceived home, and school climates, and the relationships between these variables in a theory driven etiological analysis.

Results:Adolescents with supportive home and school environments experienced lower relative odds of engagement in risk taking behavior and lower relative odds of injury. Gradients were observed between the extent of adolescent risk taking and the occurrence of injury. Interactions were not observed between risk taking behavior, perceived support in home and school climates, and injury.

Conclusions:Risk taking is common among adolescents and plays a role in the etiology of injury. Supportive social climates clearly protect adolescents from engaging in these behaviors, and also the occurrence of some forms of injury. However, once an adolescent chooses to engage in risk taking behaviour, a supportive environment may not protect them from injury.
Gall stones and chronic pancreatitis: the black box in between
Authors: Yan M-X , Li Y-Q
Published: April 2006

The relation between gall stones and chronic pancreatitis is uncertain; there are differing opinions on this issue. Firstly, gall stones are the most common reason for acute pancreatitis, but it cannot cause chronic pancreatitis. Secondly, a connection between gall stones and chronic inflammation of the pancreas might exist. Numerous studies or investigations have shown that changes associated with chronic pancreatitis are common in gallstone patients. Although it seems that gall stones might be a cause of chronic pancreatitis according to these findings, clinical and experimental studies are still needed for confirmation, and further studies are required to determine the mechanisms involved.
Leaching of nitrate from temperate forests  effects of air pollution and forest management
Authors: Gundersen Per , Schmidt Inger K , Raulund-Rasmussen Karsten
Published: April 2006

We compiled regional and continental data on inorganic nitrogen (N) in seepage and surface water from temperate forests. Currently, N concentrations in forest waters are usually well below water quality standards. But elevated concentrations are frequently found in regions with chronic N input from deposition (>810 kg ha1a1). We synthesized the current understanding of factors controlling N leaching in relation to three primary causes of N cycle disruption: (i) Increased N input (air pollution, fertilization, N2fixing plants). In European forests, elevated N deposition explains approximately half of the variability in N leaching, some of the remaining variability could be explained by differences in N availability or "N status". For coniferous forests, needle N content above 1.4% and (or) forest floor C:N ratio lower than 25 were thresholds for elevated nitrate leaching. At adjacent sites conifer forests receive higher N deposition and exhibit higher nitrate loss than deciduous forests; an exception is alder that shows substantial nitrate leaching through N fixation input. Fertilization with N poses limited risk to water quality, when applied to N-limited forests. (ii) Reduced plant uptake (clear-cut, thinning, weed control). The N cycle responses to plant cover disturbance by clear-cut are well studied. Nitrate losses peak after 23 years and are back to pre-cut levels after 35 years. Nitrogen losses increase with deposition and are higher at N rich sites. The extent and duration of the nitrate response is especially connected to the recovery of the vegetation sink. Less intensive disturbances like thinning have only minor effects on N loss. (iii) Enhanced mineralization of soil N (liming, ditching, climate change). Responses in nitrate leaching after liming may increase with N deposition and in older stands. However data on these types of N cycle disruption are too sparse to allow general conclusions on controlling factors. Nitrate leaching occurs when N deposition (input) and net mineralization (N status) exceed plant demand. A combined N flux to the soil of 50 to 60 kg ha1a1from N deposition and litterfall may be a threshold for nitrate leaching in undisturbed forests. This threshold also indicates risk of increasing losses in case of a disturbance (e.g., clear-cut). We conclude by discussing forest management options for water quality protection. These options focus on decreasing input, increasing plant uptake, increasing biomass removal, and (re)establishing immobilization and denitrification processes at the catchment scale.Key words: clear-cut, disturbance, forest management, nitrate, nitrogen cycling, nitrogen saturation.
Ultrastructural and molecular delineation of the Chytridiaceae (Chytridiales)
Authors: Letcher Peter M. , Powell Martha J. , Chambers James G. , Longcore Joyce E. , Churchill Perry F. , Harris Phillip M.
Published: April 2006

The Chytridiomycota is in need of taxonomic revision, especially the largest order, the Chytridiales. We analyzed 25 isolates in, or allied to, the Chytridium clade of this order. Isolates were selected based on one or more of the following criteria: (i) having a large subunit molecular sequence similar to that of the type of the genus Chytriomyces, (ii) having specific zoospore morphology, and (iii) currently classified as a species in the genus Chytriomyces . We examined ultrastructural characters and partial sequences of large subunit and small subunit rDNA and generated a phylogenetic hypothesis using maximum parsimony and Bayesian analyses. The sequence analyses strongly supported the Chytridiaceae, Phlyctochytrium, and Chytriomyces angularis clades, and each clade had a specific zoospore type. Developmental morphology of the thallus did not mirror the DNA-based phylogeny. Based on the results of phylogenetic analyses of sequences and ultrastructural characters, we emend the Chytridiaceae by including exogenous and polycentric development and define the family on the basis of a single zoospore type. Species identified as being in the genus Chytriomyces occur in several separate, well-supported clades along with species currently classified in seven other genera ( Asterophlyctis , Entophlyctis , Obelidium , Physocladia , Podochytrium , Rhizoclosmatium , and Siphonaria ), indicating that Chytriomyces as currently defined is polyphyletic.
Ulmus leaves and fruits from the Early–Middle Eocene of northwestern North America: systematics and implications for character evolution within Ulmaceae
Authors: Denk Thomas , Dillhoff Richard M.
Published: April 2006

Leaves and fruits of Ulmus from the Early–Middle Eocene of British Columbia and Washington are assigned to two species. Ulmus okanaganensis sp.nov. is based on leaves attached to flowering and fruiting twigs and isolated leaves and fruits. Leaves display a polymorphism ranging from large leaves with compound teeth with a blunt apex to small ones with simple teeth resembling those of Zelkova. In extant Ulmus, sucker-shoot leaves, elongation-shoot leaves, and leaves on short annual branches often display a very similar polymorphism. In the fossil, flowers are arranged in fascicles having short pedicels. Fascicles are formed in the axils of leaves of current-year shoots and appear together with the leaves. This is uncommon in modern species of Ulmus, where leaves appear either in spring on previous-year shoots or in autumn in the axils of leaves of current-year shoots. Fruits of U. okanaganensis are samaras with extremely reduced or absent wings. Unwinged fruits of modern Ulmus are typically ciliate along the margin of the endocarp and the persistent styles but only a single fruit of U. okanaganensis has been found preserving hairs. The small, shallowly lobed perianth is situated below the endocarp. A second type of foliage is assigned to Ulmus chuchuanus (Berry) LaMotte. This foliage is wider than that of U. okanaganensis and has more densely spaced secondary veins. It also has characteristic compound teeth with primary and subsidiary teeth displaying conspicuously different orientations. Leaves of U. chuchuanus co-occur with a second type of fruit but have not been found in attachment. These fruits are larger than in U. okanaganensis, with a narrow wing, persistent styles, and a large and wide persistent perianth that tapers abruptly into the perianth tube. A cladistic analysis suggests that U. okanaganensis is nested within the subgenus Ulmus, which is a paraphyletic grade basal to the subgenus Oreoptelea. Ulmus chuchuanus foliage shows affinities to the subgenus Ulmus, while the associated fruits display affinities to the subgenus Oreoptelea.
Effects of variable nitrogen fertilization on growth, gas exchange, and biomass partitioning in black spruce and tamarack seedlings
Authors: Islam M. Anisul , Macdonald S. Ellen
Published: April 2006

To compare the ability of black spruce ( Picea mariana (Mill.) BSP) and tamarack ( Larix laricina (Du Roi) K. Koch) to adjust to variable edaphic conditions, as found in natural peatlands, we varied N fertilization of seedlings in a growth chamber experiment over two growing seasons and examined growth, biomass partitioning, and gas exchange. Seedlings from both species received either high N (100 µg·L–1) or low N (10 µg·L–1) in consecutive growing seasons as follows: (i) low N and low N (LL), (ii) low N and high-N (LH), (iii) high N and low N (HL), and (iv) high N and high N (HH). Both species had greater shoot and total dry weight after 1 year in the high-N treatment as compared with seedlings grown for 1 year under low-N. For tamarack, these differences were larger and they also exhibited a positive effect of fertilization on net assimilation and water use efficiency. Only black spruce exhibited a positive growth response following the move to higher N fertilization in the second year (LL versus LH), whereas only tamarack exhibited a negative growth response following the move to lower N fertilization (HH versus HL). Still, tamarack had greater total biomass at the end of 2 years than did black spruce, irrespective of fertilizer treatment. Both species had greater total biomass in the HL treatment than in the LH treatment. Tamarack seems able to take advantage of favorable nutrient conditions, but it also experiences more dramatic growth declines under poor or deteriorating conditions. While black spruce grows more slowly than tamarack, it is somewhat buffered from declines in growth under poor or deteriorating conditions. Each species appears to be adapted in its own way to the edaphic heterogeneity that exists in natural boreal peatlands.
Morphophysiological dormancy in seeds of six endemic lobelioid shrubs (Campanulaceae) from the montane zone in Hawaii
Authors: Baskin Carol C. , Baskin Jerry M. , Yoshinaga Alvin
Published: April 2006

The purpose of this study was to investigate seed dormancy breaking and germination requirements of six woody Hawaiian endemic lobelioids (Campanulaceae). Seeds of all species had underdeveloped, physiologically dormant embryos and thus morphophysiological dormancy. Fresh seeds of Clermontia pyrularia Hillebr. and Trematolobelia macrostachys (Hook. & Arnott) A. Zahlbr. did not germinate during 4 weeks of incubation in light at 15/6, 20/10, or 25/15 °C, whereas those of Clermontia fauriei H. Lev., Clermontia hawaiiensis (Hillebr.) Rock, Clermontia kakeana Meyen, and Cyanea angustifolia (Cham.) Hillebr. germinated to 61%–85% but only at 25/15 °C. Since seeds of the latter four species eventually germinated to 84%–100% when incubated for 12–36 weeks at the three temperature regimes, fresh seeds had conditional dormancy; the physiological component of morphophysiological dormancy was nondeep. Seeds of Trematolobelia macrostachys also came out of dormancy (and germinated to 90%) during 18 weeks of incubation at each of the three temperatures regimes, whereas those of Clermontia pyrularia did so only at 15/6 °C. Simulated seasonal temperature variations did not promote dormancy break and germination in any species except Clermontia pyrularia , in which a 12-week incubation period at 25/15 °C resulted in 90% germination after seeds were moved to 20/10 °C. Seeds of all species had an absolute light requirement for germination except those of Clermontia pyrularia, which germinated to 48% in darkness. Since seeds of the six species only require high temperatures for embryo growth and the breaking of physiological dormancy, they have nondeep simple morphophysiological dormancy.
Biomass and nutrient responses of a clonal tundra sedge to climate warming
Authors: Jónsdóttir Ingibjörg S. , Khitun Olga , Stenström Anna
Published: April 2006

We explored how climate change affects biomass, nutrient status, and late-season resource-allocation patterns in a rhizomatous tundra sedge, and how differentiation and development of ramets may constrain plant responses. We simulated climate warming for 5 years at a subarctic–alpine tundra site by using open-top chambers before destructively sampling clonal fragments of the dominant and widespread sedge, Carex bigelowii Torr. ex Schwein. We found differential growth response among ramets to experimental warming, but reduced aboveground tissue nutrient concentrations across entire clonal systems. Warming did not affect biomass allocation within ramets, but it did change biomass allocation among developmental stages and ramet types (i.e., long- and short-rhizome ramets, termed guerrilla and phalanx). A positive warming effect on biomass was mostly confined to mature vegetative ramets and the response of individual plant parts was significantly greater for guerrilla ramets than for phalanx ramets. Despite the differential biomass response, warming significantly reduced nitrogen and phosphorus concentrations in aboveground tissues across all developmental stages within the integrated clonal system (10% decrease in green leaf nitrogen concentration, 18%–25% decrease in phosphorus concentration). However, late-season nutrient concentrations in storage organs (rhizomes) were not affected. Nutrient pools significantly increased in mature vegetative ramets, especially those of the guerrilla type, apparently as a result of both redistribution of nutrients among ramets and increased nutrient uptake. At the community level, estimated aboveground biomass per unit area was similar in warmed and control plots. Rhizome and dead-leaf mass and all nutrient pools per unit area were 10%–20% less in warmed plots than in controls. The ecosystem implications of the responses of C. bigelowii, a forage species favoured by a range of herbivores, to warming are a reduction in forage quality without compensation in terms of quantity and, eventually, a reduction in litter quality.
Branching, biomass distribution, and light capture efficiency in a pioneer tree, Rhus trichocarpa, in a secondary forest
Authors: Osada Noriyuki
Published: April 2006

Crown architecture and biomass distribution patterns were investigated in relation to branching and tree size in a pioneer species, Rhus trichocarpa Miq. (Anacardiaceae), in a Japanese secondary forest. Crown architecture changed with tree size and with branching. Crown depth and area were greater in taller trees. In addition, branched trees had crowns of greater depth, and crown area increased more rapidly with increasing height in branched trees as compared with unbranched trees. In contrast, biomass distribution to nonphotosynthetic and photosynthetic organs changed only with tree size and was similar in unbranched and branched trees of similar size. Light capture efficiency was related to neither height nor branching status for trees with heights of 1–2.5 m. Coexistence of unbranched and branched trees at the height around the onset of branching is possible because these trees realize similar biomass distribution patterns and light capture efficiencies. Individual leaf area and leaf area index increased with tree size in unbranched trees but decreased with tree size in branched trees. These results suggest that several leaf clusters of limited size are sparsely arranged in a large three-dimensional space in tall trees.