bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of ppGpp in
rpoS
Stationary-Phase Regulation in
Escherichia coli
Authors: Hirsch Matthew , Elliott Thomas
Published: October 2002

The bacterial sigma factor RpoS is strongly induced under a variety of stress conditions and during growth into stationary phase. Here, we used
rpoS-lac
fusions in
Escherichia coli
to investigate control acting at the level of RpoS synthesis, which is especially evident when cells approach stationary phase in rich medium. Previous work has shown that the small molecule ppGpp is required for normal levels of RpoS in stationary phase. Despite the attraction of a model in which the ppGpp level controls stationary-phase induction of RpoS, careful measurement of
rpoS-lac
expression in a mutant lacking ppGpp showed similar effects during both exponential growth and stationary phase; the main effect of ppGpp was on basal expression. In addition, a modest regulatory defect was associated with the mutant lacking ppGpp, delaying the time at which full expression was achieved by 2 to 3 h. Deletion analysis showed that the defect in basal expression was distributed over several sequence elements, while the regulatory defect mapped to the region upstream of the
rpoS
ribosome-binding site (RBS) that contains a
cis
-acting antisense element. A number of other genes that have been suggested as regulators of
rpoS
were tested, including
dksA
,
dsrA
,
barA
,
ppkx
, and
hfq
. With the exception of the
dksA
mutant, which had a modest defect in Luria-Bertani medium, none of these mutants was defective for
rpoS
stationary-phase induction. Even a short
rpoS
segment starting at 24 nucleotides upstream of the AUG initiation codon was sufficient to confer substantial stationary-phase regulation, which was mainly posttranscriptional. The effect of RBS-proximal sequence was independent of all known
trans
-acting factors, including ppGpp.
Interactions between Integrase and Excisionase in the Phage Lambda Excisive Nucleoprotein Complex
Authors: Cho Eun Hee , Gumport Richard I. , Gardner Jeffrey F.
Published: October 2002

Bacteriophage lambda site-specific recombination comprises two overall reactions, integration into and excision from the host chromosome. Lambda integrase (Int) carries out both reactions. During excision, excisionase (Xis) helps Int to bind DNA and introduces a bend in the DNA that facilitates formation of the proper excisive nucleoprotein complex. The carboxyl-terminal α-helix of Xis is thought to interact with Int through direct protein-protein interactions. In this study, we used gel mobility shift assays to show that the amino-terminal domain of Int maintained cooperative interactions with Xis. This finding indicates that the amino-terminal arm-type DNA binding domain of Int interacts with Xis.
Vaginal
Lactobacillus
Flora of Healthy Swedish Women
Authors: Vásquez Alejandra , Jakobsson Tell , Ahrné Siv , Forsum Urban , Molin Göran
Published: October 2002

Species of the
Lactobacillus acidophilus
complex are generally considered to constitute most of the vaginal
Lactobacillus
flora, but the flora varies between studies. However, this may be due to difficulties in identifying the closely related species within the
L. acidophilus
complex by using traditional methods and to variations in the vaginal status of the participants. Two hundred two isolates from the vaginal fluids of 23 Swedish women without bacterial vaginosis, as defined by the criteria of Nugent et al. (R. P. Nugent, M. A. Krohn, and S. L. Hillier, J. Clin. Microbiol. 29:297-301, 1991), were typed by randomly amplified polymorphic DNA (RAPD) analysis and identified to the species level by temporal temperature gradient gel electrophoresis, multiplex PCR, and 16S ribosomal DNA sequencing. The vaginal flora of most participants was dominated by a single RAPD type, but five of them harbored two RAPD types representing two different species or strains. The most frequently occurring species were
Lactobacillus crispatus
,
Lactobacillus gasseri
,
Lactobacillus iners
, and
Lactobacillus jensenii. L. iners
has not previously been reported as one of the predominant
Lactobacillus
species in the vagina.
Fluorescent Amplified Fragment Length Polymorphism Probabilistic Database for Identification of Bacterial Isolates from Urinary Tract Infections
Authors: Kassama Yankuba , Rooney Paul J. , Goodacre Royston
Published: October 2002

The ability of the fluorescent amplified fragment length polymorphism (FAFLP) technique to identify bacterial isolates from urinary tract infections (UTIs) was investigated. FAFLP was carried out using the single primer combination
Mse
I plus CT and
Eco
RI plus 0, and information-rich FAFLP profiles were generated from all 69 UTI isolates studied, which comprised both gram-negative and gram-positive bacteria encompassing eight genera. The genetic relatedness of these 69 bacteria was determined by cluster analysis, and this revealed eight main groups corresponding to the eight bacterial genera. Finer discrimination on the same dendrogram showed species and subspecies differentiations, thus demonstrating the potential of FAFLP for describing a wide diversity range within microbial populations. The interpretation of FAFLP profiles is often complicated because it relies upon the investigator interpreting dendrograms; this process may be subjective if the tree is complicated, particularly if it includes polytomies (unresolved nodes). Therefore, we have developed a method based on Bayes' theorem for the identification of bacteria against an FAFLP probabilistic identification matrix. Thus, FAFLP is suitable for the objective identification of causal agents of UTI, and the procedure offers great potential in the clinical laboratory.
Rapid Identification of Pathogenic Fungi Directly from Cultures by Using Multiplex PCR
Authors: Luo Guizhen , Mitchell Thomas G.
Published: October 2002

A multiplex PCR method was developed to identify simultaneously multiple fungal pathogens in a single reaction. Five sets of species-specific primers were designed from the internal transcribed spacer (ITS) regions, ITS1 and ITS2, of the rRNA gene to identify
Candida albicans
,
Candida glabrata
,
Candida parapsilosis
,
Candida tropicalis
, and
Aspergillus fumigatus
. Another set of previously published ITS primers, CN4 and CN5, were used to identify
Cryptococcus neoformans
. Three sets of primers were used in one multiplex PCR to identify three different species. Six different species of pathogenic fungi can be identified with two multiplex PCRs. Furthermore, instead of using templates of purified genomic DNA, we performed the PCR directly from yeast colonies or cultures, which simplified the procedure and precluded contamination during the extraction of DNA. A total of 242 fungal isolates were tested, representing 13 species of yeasts, four species of
Aspergillus
, and three zygomycetes. The multiplex PCR was tested on isolated DNA or fungal colonies, and both provided 100% sensitivity and specificity. However, DNA from only about half the molds could be amplified directly from mycelial fragments, while DNA from every yeast colony was amplified. This multiplex PCR method provides a rapid, simple, and reliable alternative to conventional methods to identify common clinical fungal isolates.
Viral RNA Mutations Are Region Specific and Increased by Ribavirin in a Full-Length Hepatitis C Virus Replication System
Authors: Contreras Ana Maria , Hiasa Yoichi , He Wenping , Terella Adam , Schmidt Emmett V. , Chung Raymond T.
Published: October 2002

High rates of genetic variation ensure the survival of RNA viruses. Although this variation is thought to result from error-prone replication, RNA viruses must also maintain highly conserved genomic segments. A balance between conserved and variable viral elements is especially important in order for viruses to avoid “error catastrophe.” Ribavirin has been shown to induce error catastrophe in other RNA viruses. We therefore used a novel hepatitis C virus (HCV) replication system to determine relative mutation frequencies in variable and conserved regions of the HCV genome, and we further evaluated these frequencies in response to ribavirin. We sequenced the 5′ untranslated region (5′ UTR) and the core, E2 HVR-1, NS5A, and NS5B regions of replicating HCV RNA isolated from cells transfected with a T7 polymerase-driven full-length HCV cDNA plasmid containing a
cis
-acting hepatitis delta virus ribozyme to control 3′ cleavage. We found quasispecies in the E2 HVR-1 and NS5B regions of untreated replicating viral RNAs but not in conserved 5′ UTR, core, or NS5A regions, demonstrating that important
cis
elements regulate mutation rates within specific viral segments. Neither T7-driven replication nor sequencing artifacts produced these nucleotide substitutions in control experiments. Ribavirin broadly increased error generation, especially in otherwise invariant regions, indicating that it acts as an HCV RNA mutagen in vivo. Similar results were obtained in hepatocyte-derived cell lines. These results demonstrate the potential utility of our system for the study of intrinsic factors regulating genetic variation in HCV. Our results further suggest that ribavirin acts clinically by promoting nonviable HCV RNA mutation rates. Finally, the latter result suggests that our replication model may be useful for identifying agents capable of driving replicating virus into error catastrophe.
Involvement of the Leader Sequence in Sendai Virus Pathogenesis Revealed by Recovery of a Pathogenic Field Isolate from cDNA
Authors: Fujii Yutaka , Sakaguchi Takemasa , Kiyotani Katsuhiro , Huang Cheng , Fukuhara Noriko , Egi Yoshiko , Yoshida Tetsuya
Published: October 2002

We previously demonstrated that a systematic passage of a pathogenic field isolate of Sendai virus (SeV), the Hamamatsu strain, in embryonated eggs caused attenuation of virulence to mice, and we isolated viral clones of distinct virulence (K. Kiyotani et al. Arch. Virol. 146:893-908, 2001). One of the clones, E15cl2, which was obtained from the virus at the 15th egg passage of E0, the parental Hamamatsu clone for egg passage, had 165-fold-attenuated virulence to mice and possessed only four mutations in the entire 15,384-base genome: in an antigenomic sense, U to A at position 20 (U
20
A) and U to A at position 24 (U
24
A) in the leader sequence, the promoter for transcription and replication, and A to G at position 9346 (silent) and A to U at position 12174 (Ser to Cys) in the L gene. To examine the possibility that leader mutations affect virus pathogenesis, we recovered live viruses from cDNA derived from the Hamamatsu strain. A mutant virus possessing either a mutation of U
20
A or U
24
A in the leader sequence showed a slightly lower pathogenicity than that of the parental virus, whereas a double mutant virus possessing both of the mutations showed 25-fold-attenuated virulence, accompanying a significantly lower virus replication in the mouse lung. Replications of the leader mutant viruses were also impaired in a primary culture of mouse pulmonary epithelial cells but not in chicken embryo fibroblasts. These findings suggest that leader mutations of SeV affect virus pathogenesis by altering virus replication in a host-dependent manner.
Modification of Asn374 of nsP1 Suppresses a Sindbis Virus nsP4 Minus-Strand Polymerase Mutant
Authors: Fata Cori L. , Sawicki Stanley G. , Sawicki Dorothea L.
Published: October 2002

Our recent study (C. L. Fata, S. G. Sawicki, and D. L. Sawicki, J. Virol. 76:8632-8640, 2002) found minus-strand synthesis to be temperature sensitive in vertebrate and invertebrate cells when the Arg183 residue of the Sindbis virus nsP4 polymerase was changed to Ser, Ala, or Lys. Here we report the results of studies identifying an interacting partner of the region of the viral polymerase containing Arg183 that suppresses the Ser183 codon mutation. Large-plaque revertants were observed readily following growth of the nsP4 Ser183 mutant at 40°C. Fifteen revertants were characterized, and all had a mutation in the Asn374 codon of nsP1 that changed it to either a His or an Ile codon. When combined with nsP4 Ser183, substitution of either His374 or Ile374 for Asn374 restored wild-type growth in chicken embryo fibroblast (CEF) cells at 40°C. In
Aedes albopictus
cells at 34.5°C, neither nsP1 substitution suppressed the nsP4 Ser183 defect in minus-strand synthesis. This argued that the nsP4 Arg183 residue itself is needed for minus-strand replicase assembly or function in the mosquito environment. The nsP1 His374 suppressor when combined with the wild-type nsP4 gave greater than wild-type levels of viral RNA synthesis in CEF cells at 40°C (∼140%) and in
Aedes
cells at 34.5°C (200%). Virus producing nsP1 His374 and wild-type nsP4 Arg183 made more minus strands during the early period of infection and before minus-strand synthesis ceased at about 4 h postinfection. Shirako et al. (Y. Shirako, E. G. Strauss, and J. H. Strauss, Virology 276:148-160, 2000) identified amino acid substitutions in nsP1 and nsP4 that suppressed mutations that changed the N-terminal Tyr of nsP4. The nsP4 N-terminal mutants were defective also in minus-strand synthesis. Our study implicates an interaction between another conserved nsP1 region and an internal region, predicted to be in the finger domain, of nsP4 for the formation or activity of the minus-strand polymerase. Finally, the observation that a single point mutation in nsP1 results in minus-strand synthesis at greater than wild-type levels supports the concept that the wild-type nsP sequences are evolutionary compromises.
A Single Amino Acid Mutation in the PA Subunit of the Influenza Virus RNA Polymerase Inhibits Endonucleolytic Cleavage of Capped RNAs
Authors: Fodor Ervin , Crow Mandy , Mingay Louise J. , Deng Tao , Sharps Jane , Fechter Pierre , Brownlee George G.
Published: October 2002

The influenza A virus RNA-dependent RNA polymerase consists of three subunits—PB1, PB2, and PA. The PB1 subunit is the catalytically active polymerase, catalyzing the sequential addition of nucleotides to the growing RNA chain. The PB2 subunit is a cap-binding protein that plays a role in initiation of viral mRNA synthesis by recruiting capped RNA primers. The function of PA is unknown, but previous studies of temperature-sensitive viruses with mutations in PA have implied a role in viral RNA replication. In this report we demonstrate that the PA subunit is required not only for replication but also for transcription of viral RNA. We mutated evolutionarily conserved amino acids to alanines in the C-terminal region of the PA protein, since the C-terminal region shows the highest degree of conservation between PA proteins of influenza A, B, and C viruses. We tested the effects of these mutations on the ability of RNA polymerase to transcribe and replicate viral RNA. We also tested the compatibility of these mutations with viral viability by using reverse-genetics techniques. A mutant with a histidine-to-alanine change at position 510 (H510A) in the PA protein of influenza A/WSN/33 virus showed a differential effect on transcription and replication. This mutant was able to perform replication (vRNA→cRNA→vRNA), but its transcriptional activity (vRNA→mRNA) was negligible. In vitro analyses of the H510A recombinant polymerase, by using transcription initiation, vRNA-binding, capped-RNA-binding, and endonuclease assays, suggest that the primary defect of this mutant polymerase is in its endonuclease activity.
Nucleoside Analog Resistance Caused by Insertions in the Fingers of Human Immunodeficiency Virus Type 1 Reverse Transcriptase Involves ATP-Mediated Excision
Authors: Boyer Paul L. , Sarafianos Stefan G. , Arnold Edward , Hughes Stephen H.
Published: October 2002

Although anti-human immunodeficiency virus type 1 (HIV-1) therapy has prolonged the lives of patients, drug resistance is a significant problem. Of particular concern are mutations that cause cross-resistance to a particular class of drugs. Among the mutations that cause resistance to several nucleoside analogs are the insertion of amino acids in the fingers subdomain of HIV-1 reverse transcriptase (RT) at positions 69 and 70. These insertions are usually associated with changes in the flanking amino acids and with a change to F or Y at position 215. We have proposed that the T215F/Y mutation makes the binding of ATP to HIV-1 RT more effective, which increases the excision of 3-azido-3′-deoxythymidine-5′-monophosphate (AZTMP) in vitro and increases zidovudine (AZT) resistance in vivo. Although the mechanism of AZT resistance involves enhanced excision, resistance to 3TC involves a block to incorporation of the analog. We measured the effects of fingers insertion mutations on the misincorporation and excision of several nucleoside analogs. RT variants with the amino acid insertions in the fingers and T215Y have a decreased level of misincorporation of ddATP and 3TCTP. These mutants also have the ability to excise AZTMP by ATP-dependent pyrophosphorylysis. However, unlike the classic AZT resistance mutations (M41L/D67N/K70R/T215Y or F/K219E or Q), the combination of the amino acid insertions in the fingers and the T215Y mutation allows efficient excision of ddTMP and d4TMP, even when relatively high levels of deoxynucleoside triphosphates are present in the reaction. Although the dideoxynucleoside analogs of other nucleosides were excised more slowly than AZTMP, ddTMP, and d4TMP, the mutants with the fingers insertion and T215Y excised all of the nucleoside analogs that were tested more efficiently than wild-type RT or a mutant RT carrying the classical AZT resistance mutations. In the ternary complex (RT/template-primer/dNTP), the presence of the bound dNTP prevents the end of the primer from gaining access to the nucleotide binding site (N site) where excision occurs. Gel shift analysis showed that the amino acid insertions in the fingers destabilized the ternary complex compared to wild-type HIV-1 RT. If the ternary complex is unstable, the end of the primer can gain access to the N site and excision can occur. This could explain the enhanced excision of the nucleoside analogs.
In Vivo Gene Transfer Using a Nonprimate Lentiviral Vector Pseudotyped with Ross River Virus Glycoproteins
Authors: Kang Yubin , Stein Colleen S. , Heth Jason A. , Sinn Patrick L. , Penisten Andrea K. , Staber Patrick D. , Ratliff Kenneth L. , Shen Hong , Barker Carrie K. , Martins Inês , Sharkey C. Matthew , Sanders David Avram , McCray Paul B. , Davidson Beverly L.
Published: October 2002

Vectors derived from lentiviruses provide a promising gene delivery system. We examined the in vivo gene transfer efficiency and tissue or cell tropism of a feline immunodeficiency virus (FIV)-based lentiviral vector pseudotyped with the glycoproteins from Ross River Virus (RRV). RRV glycoproteins were efficiently incorporated into FIV virions, generating preparations of FIV vector, which after concentration attain titers up to 1.5 × 10
8
TU/ml. After systemic administration, RRV-pseudotyped FIV vectors (RRV/FIV) predominantly transduced the liver of recipient mice. Transduction efficiency in the liver with the RRV/FIV was ca. 20-fold higher than that achieved with the vesicular stomatitis virus G protein (VSV-G) pseudotype. Moreover, in comparison to VSV-G, the RRV glycoproteins caused less cytotoxicity, as determined from the levels of glutamic pyruvic transaminase and glutamic oxalacetic transaminase in serum. Although hepatocytes were the main liver cell type transduced, nonhepatocytes (mainly Kupffer cells) were also transduced. The percentages of the transduced nonhepatocytes were comparable between RRV and VSV-G pseudotypes and did not correlate with the production of antibody against the transgene product. After injection into brain, RRV/FIV preferentially transduced neuroglial cells (astrocytes and oligodendrocytes). In contrast to the VSV-G protein that targets predominantly neurons, <10% of the brain cells transduced with the RRV pseudotyped vector were neurons. Finally, the gene transfer efficiencies of RRV/FIV after direct application to skeletal muscle or airway were also examined and, although transgene-expressing cells were detected, their proportions were low. Our data support the utility of RRV glycoprotein-pseudotyped FIV lentiviral vectors for hepatocyte- and neuroglia-related disease applications.
Persistence of Wild-Type Virus and Lack of Temporal Structure in the Latent Reservoir for Human Immunodeficiency Virus Type 1 in Pediatric Patients with Extensive Antiretroviral Exposure
Authors: Ruff Christian T. , Ray Stuart C. , Kwon Patricia , Zinn Rebekah , Pendleton Amanda , Hutton Nancy , Ashworth Roxann , Gange Stephen , Quinn Thomas C. , Siliciano Robert F. , Persaud Deborah
Published: October 2002

Although highly active antiretroviral therapy (HAART) for human immunodeficiency virus type 1 (HIV-1) infection can reduce levels of HIV-1 RNA in plasma to below the limit of detection, replication-competent forms of the virus persist in all infected individuals. One form of persistence involves a stable reservoir of latent but potentially infectious virus that resides in resting memory CD4
+
T cells. The mechanisms involved in maintaining this latent reservoir are incompletely understood. In the present study, we examined the dynamic characteristics of this reservoir in a cohort of children who developed drug-resistant HIV-1 as a result of extensive exposure to inadequately suppressive one- or two-drug regimens prior to the advent of HAART. We have previously shown that drug-resistant viruses selected by nonsuppressive pre-HAART regimens can enter and persist in this reservoir. We have extended these findings here by demonstrating that archival wild-type HIV-1 persists in this reservoir despite the fact that in these patients drug-resistant mutants have been favored by the selective conditions for many years. Phylogenetic analysis of replication-competent viruses persisting in resting CD4
+
T cells revealed a striking lack of temporal structure in the sense that isolates obtained at later time points did not show greater sequence divergence than isolates from earlier time points. The persistence of drug-sensitive virus and the lack of temporal structure in the latent reservoir provide genetic evidence for the idea that HIV-1 can persist in a latent form free of selective pressure from antiretroviral drugs in long-lived resting memory CD4
+
T cells. Although there may be other mechanisms for viral persistence, this stable pool of latently infected cells is of significant concern because of its potential to serve as a lasting source of replication-competent viruses, including the infecting wild-type form and all drug-resistant variants that have arisen subsequently.
Molecular Evolution of Hepatitis A Virus: a New Classification Based on the Complete VP1 Protein
Authors: Costa-Mattioli Mauro , Cristina Juan , Romero Héctor , Perez-Bercof Raoul , Casane Didier , Colina Rodney , Garcia Laura , Vega Ines , Glikman Graciela , Romanowsky Victor , Castello Alejandro , Nicand Elisabeth , Gassin Michelle , Billaudel Sylviane , Ferré Virginie
Published: October 2002

Hepatitis A virus
(HAV) is a positive-stranded RNA virus in the genus
Hepatovirus
in the family
Picornaviridae
. So far, analysis of the genetic variability of HAV has been based on two discrete regions, the VP1/2A junction and the VP1 N terminus. In this report, we determined the nucleotide and deduced amino acid sequences of the complete VP1 gene of 81 strains from France, Kosovo, Mexico, Argentina, Chile, and Uruguay and compared them with the sequences of seven strains of HAV isolated elsewhere. Overall strain variation in the complete VP1 gene was found to be as high as 23.7% at the nucleotide level and 10.5% at the amino acid level. Different phylogenetic methods revealed that HAV sequences form five distinct and well-supported genetic lineages. Within these lineages, HAV sequences clustered by geographical origin only for European strains. The analysis of the complete VP1 gene allowed insight into the mode of evolution of HAV and revealed the emergence of a novel variant with a 15-amino-acid deletion located on the VP1 region where neutralization escape mutations were found. This could be the first antigenic variant of HAV so far identified.
The Core of Bluetongue Virus Binds Double-Stranded RNA
Authors: Diprose J. M. , Grimes J. M. , Sutton G. C. , Burroughs J. N. , Meyer A. , Maan S. , Mertens P. P. C. , Stuart D. I.
Published: October 2002

Double-stranded RNA (dsRNA) viruses conceal their genome from the host to avoid triggering unfavorable cellular responses. The crystal structure of the core of one such virus, bluetongue virus, reveals an outer surface festooned with dsRNA. This may represent a deliberate strategy to sequester dsRNA released from damaged particles to prevent host cell shutoff.
The Human Cytomegalovirus Ribonucleotide Reductase Homolog UL45 Is Dispensable for Growth in Endothelial Cells, as Determined by a BAC-Cloned Clinical Isolate of Human Cytomegalovirus with Preserved Wild-Type Characteristics
Authors: Hahn Gabriele , Khan Hanna , Baldanti Fausto , Koszinowski Ulrich H. , Revello M. Grazia , Gerna Giuseppe
Published: October 2002

An endothelial cell-tropic and leukotropic human cytomegalovirus (HCMV) clinical isolate was cloned as a fusion-inducing factor X-bacterial artificial chromosome in
Escherichia coli
, and the ribonucleotide reductase homolog UL45 was deleted. Reconstituted virus RVFIX and RVΔUL45 grew equally well in human fibroblasts and human endothelial cells. Thus, UL45 is dispensable for growth of HCMV in both cell types.
The Structural Basis for Hydrolysis Resistance in the Esters of (2-Formylphenyl)boronic Acid 2,4-Dinitrophenylhydrazones
Authors: Groziak Michael P. , Robinson Paul D.
Published: October 2002

Under conditions that typically afford bicyclic boron heterocycles directly, (2-formylphenyl)boronic acids react with 2,4-dinitrophenylhydrazine in ethanol to give highly waterresistant diethyl boronate esters. Two such 2,4-dinitrophenylhydrazones were prepared and their X-ray crystal structures determined. Contrary to a previous suggestion that their unusual stability is due to an intramolecular N→B coordination giving a six-membered BN2C3 ring system based on a (Z)-hydrazone, these compounds instead were found to be (E)-hydrazones internally stabilized by a weak intramolecular interaction between nitrogen and boron from within a five-membered ring. Further study revealed that the electron deficiency of the starting hydrazine reagent plays a key role in determining the structure of the hydrazone isolated, and that the water-resistant boronate esters can be hydrolyzed under forcing conditions to the boronic acids.
Achilles tendinopathy: some aspects of basic science and clinical management
Authors: Kader D , Saxena A , Movin T , Maffulli N
Published: October 2002

Achilles tendinopathy is prevalent and potentially incapacitating in athletes involved in running sports. It is a degenerative, not an inflammatory, condition. Most patients respond to conservative measures if the condition is recognised early. Surgery usually involves removal of adhesions and degenerated areas and decompression of the tendon by tenotomy or measures that influence the local circulation.
A comparison of physiological responses and rating of perceived exertion in two modes of aerobic exercise in men and women over 50 years of age
Authors: Grant S , Corbett K , Todd K , Davies C , Aitchison T , Mutrie N , Byrne J , Henderson E , Dargie H J
Published: October 2002

Objectives: To compare the physiological responses and ratings of perceived exertion to aerobic dance and walking sessions completed at a self selected pace.

Methods: Six women and six men with a sample mean (SD) age of 68 (7) years completed aerobic dance and walking sessions in random order. A treadmill test was performed by each subject from which peak oxygen uptake (V̇o2) and maximum heart rates (HRmax) were determined. During the aerobic dance and walking sessions, heart rate and V̇o2were measured continuously throughout. Rate of perceived exertion (RPE) was measured every three minutes throughout the session.

Results: The sample means (SD) for %peak V̇o2were 67 (17)% for the aerobic dance sessions and 52 (10)% for the walking sessions, and the %HRmax sample means (SD) were 74 (12)% for the aerobic dance sessions and 60 (8)% for walking sessions. The sample mean (SD) RPE for the aerobic dance sessions was 11 (2), and for the walking sessions it was 10 (2).

Conclusions: %peak V̇o2, %HRmax, and RPE were significantly higher for aerobic dance than for walking. However, both the aerobic dance and walking sessions were of adequate intensity to improve aerobic fitness in most subjects. Further investigation into the relation between RPE and %peak V̇o2in a field setting over representative exercise time periods would be useful.
Acquisition of a chronic subdural haematoma during training for competitive race walking?
Authors: Carmont M R , Mahattanakul W , Pigott T
Published: October 2002

A 65 year old man, anticoagulated for cardiac problems, developed hemiparesis while training for race walking. A computed tomography scan showed a chronic subdural haematoma. This is the first report of a chronic subdural haematoma possibly caused by the jarring action of race walking.
Femoral neck stress fracture: the importance of clinical suspicion and early review
Authors: Clough T M
Published: October 2002

Stress fracture of the femoral neck is rare and often initially missed. A high index of clinical suspicion is required in athletes presenting with a history of insidious onset, exertional groin pain and pain at the extremes of hip motion on examination. Regular review is recommended to prevent progression of the stress fracture to a displaced fracture, as this significantly worsens long term outcome.
Older driver involvements in police reported crashes and fatal crashes: trends and projections
Authors: Lyman S , Ferguson S A , Braver E R , Williams A F
Published: October 2002

Objectives:Older drivers have become a larger part of the driving population and will continue to do so as the baby boomers reach retirement age. The purpose of this study was to identify the potential effects of this population increase on highway safety.

Methods:Driver involvement rates for all police reported crashes were calculated per capita, per licensed driver, and per vehicle-mile of travel for 1990 and 1995. Also, driver involvement rates for fatal crashes were calculated for 1983, 1990, and 1995. Based on current crash rates per licensed driver and estimates of the future number of licensed drivers, projections of crashes involving drivers aged 65 and older were made for years 2010, 2020, and 2030.

Results:Driver crash involvement rates per capita decreased with age, but fatal involvement rates per capita increased starting at age 70. The same pattern existed for involvement rates per licensed driver. For both all crashes and fatal crashes, involvement rates per mile driven increased appreciably at age 70. Using projections of population growth, it was estimated that for all ages there will be a 34% increase in the number of drivers involved in police reported crashes and a 39% increase in the number involved in fatal crashes between 1999 and 2030. In contrast, among older drivers, police reported crash involvements are expected to increase by 178% and fatal involvements may increase by 155% by 2030. Drivers aged 65 and older will account for more than half of the total increase in fatal crashes and about 40% of the expected increase in all crash involvements; they are expected to account for as much as 25% of total driver fatalities in 2030, compared with 14% presently.

Conclusions:By most measures, older drivers are at less risk of being involved in police reported crashes but at higher risk of being in fatal crashes. Although any projections of future crash counts have inherent uncertainty, there is strong evidence that older drivers will make up a substantially larger proportion of drivers involved in fatal crashes by 2030 because of future increases in the proportion of the population aged 65 and older, and trends toward increased licensure rates and higher annual mileage among older persons. Countermeasures to reduce the anticipated death toll among older drivers should address the increased susceptibility to injury of older vehicle occupants in crashes.
Participation in maternal serum screening following screen positive results in a previous pregnancy
Authors: Rausch D.N. , Lambert-Messerlian G.M. , Canick J.A.
Published: October 2002

Objective To determine whether women who have had a positive serum screening result in one pregnancy have a lower rate of participation in screening in their next pregnancy.

Setting The Women and Infants Hospital triple marker screening programme.

Methods Pregnancy and screening information was collected from laboratory and hospital databases to compare subsequent screening participation in women who were screen negative and screen positive for risk of Down's syndrome (DS) or neural tube defect (NTD) pregnancy.

Results In an age matched comparison, 108 women who had a previous screen positive result were significantly less likely than 108 women who were screen negative to participate in maternal serum screening in their next pregnancy. When examined according to type of screen positive result, the effect was significant for both those who were screen positive for DS and those who were screen positive for NTD. The degree of risk in screen positive women did not significantly affect their uptake of screening in the next pregnancy.

Conclusions Anxiety related to a screen positive result probably causes decreased participation in maternal serum screening in the next pregnancy. Reducing the screen positive rate in prenatal serum screening would alleviate maternal anxiety and would probably lead to more stable participation.
The sensitivity, specificity, and positive predictive value of screening mammography and symptomatic status
Authors: Kavanagh A.M. , Giles G.G. , Mitchell H. , Cawson J.N.
Published: October 2002

Objective To examine whether the accuracy of screening mammography varies according to symptomatic status reported at the time of screening.

Setting Victoria, Australia, where free biennial screening is provided to women aged 40 and older.

Methods We examined the sensitivity, specificity, and the positive predictive value of screening mammography by symptom status in 106 826 women from Victoria, who attended for first round mammography in 1994 and who did not have a personal history of breast cancer. Symptomatic status was divided into the following categories: asymptomatic; significant symptoms, if the woman reported a breast lump and/or blood stained or watery nipple discharge; and other symptoms, if reported. Unconditional logistic regression modelling was used to adjust for age, use of hormone replacement therapy (HRT), and family history.

Results Sensitivity was lower for women with other symptoms (60.0%) than asymptomatic women (75.6%), or women with significant symptoms (80.8%). Specificity was lower for women with significant symptoms (73.7%) than asymptomatic women (94.9%), or women with other symptoms (95.4%). Among women who had invasive cancer detected during screening interval, women with other symptoms were more likely to get a false negative result (odds ratio 1.79, 95% confidence interval 1.03 to 3.04) than asymptomatic women, after adjusting for age, use of HRT, and family history.

Conclusion The lower sensitivity in women with other symptoms requires further investigation. Possible explanations include increased breast density and poor image quality. The high sensitivity in women with significant symptoms is probably due to more cautious radiological practice, which has also resulted in low specificity in this group.
Faecal occult blood screening for colorectal cancer at Nottingham: details of the verification process
Authors: Robinson M.H. , Rodrigues V.C. , Hardcastle J.D. , Chamberlain J.O. , Mangham C.M. , Moss S.M.
Published: October 2002

Cause specific mortality statistics derived from death certificates are highly dependent upon the accuracy of certification by the attending physician. In the Nottingham colorectal cancer screening trial, there were 12 624 deaths among the screening group and 12 515 among the control group during the period under consideration. There was no significant difference in all cause mortality rate (excluding deaths due to colorectal cancer) between the two study groups (rate ratio = 1.01, 95% confidence interval = 0.99 to 1.03). Disease specific mortality rates did not differ significantly between the two groups either. Overall, the agreement between verified and certified cause of death was 86%. Using the certified cause of death would have resulted in an underestimation bias of 6.27% for colorectal cancer deaths.
Predictors of attendance in the United Kingdom flexible sigmoidoscopy screening trial
Authors: Sutton S. , Wardle J. , Taylor T. , McCaffery K. , Williamson S. , Edwards R. , Cuzick J. , Hart A. , Northover J. , Atkin W.
Published: October 2002

Objective To investigate predictors of attendance in the United Kingdom flexible sigmoidoscopy screening trial.

Design Prospective design in which participants completed a postal questionnaire before being sent their invitation for screening.

Setting Welwyn Garden City and Leicester, United Kingdom.

Participants A total of 2758 patients aged 55 to 64, registered with general practices in the two centres, who (a) expressed interest in having the screening test, (b) completed a postal questionnaire, and (c) were subsequently invited for screening.

Main resultsThe attendance rate among questionnaire responders was 76.1%. Multiple logistic regression analysis yielded a final model that included nine independent predictors of attendance. Patients with the following characteristics were more likely to attend: men; home owners; non-smokers; those who had regular check ups at the dentist; those with better subjective health; those who minded less about having medical tests; those who said they would definitely rather than probably take up the offer of sigmoidoscopy screening; and those who perceived less barriers and more benefits to having the test.

Conclusions The findings are broadly consistent with previous studies of screening participation, although subjective health emerged as an important predictor in this study. There was no evidence for “reverse targeting”: attenders were not at lower (or higher) risk for colorectal cancer compared with non-attenders. The findings relating to attitudes and beliefs could be used in efforts to improve attendance, for example by developing information leaflets that address barriers to screening. Other findings could be used to target interventions to subgroups that have relatively low rates of screening participation.
Telling people about screening programmes and screening test results: how can we do it better?
Authors: Goyder E. , Barratt A. , Irwig L.M.
Published: October 2002

To make an informed choice about whether to be screened, people need information that allows them to weigh up the benefits and harms of screening. To understand their screening test results they require even more information. Yet currently, people attending a screening programme or considering a screening test may only be told that the test can detect disease or risk factors for disease, and that early intervention improves outcomes. When given their test results, people are generally only told the test was abnormal (“positive”) or normal (“negative”). We believe that information given before and after the screening test can, and should, be improved. This will probably require information that includes both the benefits and harms of screening and is probabilistic. Indeed, we believe the traditional dichotomisation of screening test results into positive and negative is problematic, and could be replaced by standard use of risks or probabilistic data before and after screening. The relevant risk data could be explained in a range of ways, for example, quantitatively, qualitatively, and/or by “anchoring” to everyday experiences. In this paper we explore why dichotomisation of screening test results is problematic and look at the adverse consequences of presenting test results in terms of true and false, positive and negative. We present some ideas on alternative ways of providing information on screening programmes and screening test results. Our aim is to stimulate debate about these issues and to provide some starting points which could be further developed and evaluated in a wide range of screening programmes.
Maternal thyroid deficiency and pregnancy complications: implications for population screening
Authors: Allan W.C. , Haddow J.E. , Palomaki G.E. , Williams J.R. , Mitchell M.L. , Hermos R.J. , Faix J.D. , Klein R.Z.
Published: October 2002

Objective To examine the relation between certain pregnancy complications and thyroid stimulating hormone (TSH) measurements in a cohort of pregnant women.

Methods TSH was measured in sera obtained from women during the second trimester as part of routine prenatal care. Information was then collected about vaginal bleeding, premature delivery, low birthweight, abruptio placentae, pregnancy induced hypertension, need for cesarean section, low Apgar scores, and fetal and neonatal death.

Results Among 9403 women with singleton pregnancies, TSH measurements were 6 mU/l or greater in 209 (2.2%). The rate of fetal death was significantly higher in those pregnancies (3.8%) than in the women with TSH less than 6 mU/l (0.9%, odds ratio 4.4, 95% confidence interval 1.9–9.5). Other pregnancy complications did not occur more frequently

Conclusion From the second trimester onward, the major adverse obstetrical outcome associated with raised TSH in the general population is an increased rate of fetal death. If thyroid replacement treatment avoided this problem this would be another reason to consider population screening.
Effect of distance and social disadvantage on the response to invitations to attend mammography screening
Authors: Hyndman J.C.G. , Holman C.D.J. , Dawes V.P.
Published: October 2002

Study objectivesTo investigate whether public response to an invitation to attend mammography screening can be increased by strategic relocation of the clinics.

Methods Women invited to attend mammography screening were classified by attendance, socioeconomic status, and distance from their screening clinic. A geographic information system was used to investigate whether the response could be increased by relocating clinics to facilitate access.

Setting The metropolitan city of Perth in Western Australia with six fixed site, publicly funded, mammography screening clinics.

Main resultsWomen from disadvantaged areas, not screened previously by the mammography screening programme, had a higher response to an invitation to attend screening if they lived within 3 km of their closest clinics (12%) than if they lived further away (8%). Theoretically, the response of the target population could be increased if the existing clinics were replaced by six new clinics located closer to disadvantaged areas.

Conclusions Public health planners should be aware of the use of geographic information systems to model optimum locations of health care facilities, and be willing to assess the potential target population response to those locations.
Opportunistic screening for chlamydia infection in general practice: can we reach young women?
Authors: Santer M. , Warner P. , Wyke S. , Sutherland S.
Published: October 2002

Objective To study opportunistic screening in primary care, in such a way that would include teenage women.

Setting Screening for chlamydia infection was offered opportunistically in eight general practices in Edinburgh to women aged ≤ 35 years attending for cervical smear, and women aged ≤ 20 years attending for contraception. The numbers of women eligible to be offered screening were 901 in the cervical smear group, and 595 in the contraception group.

Results Effective screening rate (offered test, consented, and urine sample returned) was 30% for the cervical smear group compared with 23% for the contraception group. Among those tested, chlamydia prevalence was strongly associated with young age, ranging from 11.8% in those <18 years, to 0% in those >25 years. Number of sexual partners in past year did not improve prediction of infection.

Conclusion These findings raise concerns regarding the feasibility of opportunistic screening in general practice, particularly for those with highest prevalence of chlamydia—teenage women.
Oral cancer screening as an integral part of general health screening in Tokoname City, Japan
Authors: Nagao T. , Miyazaki H. , Fujiwara K. , Warnakulasuriya S. , Ikeda N. , Fukano H.
Published: October 2002

Objectives To measure the attendance and compliance rates in oral mucosal screening (OMS) offered as part of a general health screen (GHS) undertaken as an organised programme in Japan.

Methods In 1996, all adults over the age of 40 years resident in Tokoname City were invited by letter to attend a free GHS annually, conducted by the municipal cooperation and the medical and dental societies of Tokoname City. In the later years only those who attended in 1996 were reinvited. Females aged less than 39 years were also allowed to attend if they wished to participate in the GHS. The GHS consisted of completion of a self administered questionnaire to identify past and current illnesses and any medications used by the screened population coupled with a routine physical check, chest x ray, ECG, and blood and urine examination. The GHS was programmed annually during the years 1996 to 1998. All those attending the GHS were invited to participate in an OMS conducted under the same roof by a visiting dentist (n=37). A referral pathway was established for screen positives requiring follow up.

Results A total of 19 305 subjects (5955 males, 13 350 females; mean age 59.2 years; 7033 in 1996, 6289 in 1997, and 5983 in 1998) attended the GHS. Of those who attended the GHS, 19 056 (98.7%) attended the OMS (1.3% refused). This rate was fairly constant over the three years. Excluding repeat examinations, new cases recruited for OMS over the three years were 8723. Of those participating in OMS, 4269 (60.7%) attended all three years. In the cohorts examined, screening dentists recorded oral mucosal lesions in 5.4% in 1996, in 4.0% in 1997, and in 2.6% in 1998. Overall, this amounted to a positive detection rate of 4.1%, or 4.9% excluding repeat examinations. A higher prevalence of oral pre-cancer was recorded among male smokers.

Conclusions The overall results suggest that although compliance with attending a free GHS was low (26.2%) among Japanese subjects over 40 years of age, of those who complied 74–76% reattended annually. Hence a satisfactory participation rate can be obtained in Japan for OMS when this is coupled to a GHS conducted at the same visit.