DNA immunisation with minimalistic expression constructs

The low efficacy obtained in large animals makes plasmid-based DNA vaccines commercially unviable. Another concern is the presence of antibiotic resistance markers on virtually all conventional plasmids. Here we describe the use of minimalistic, immunogenically defined gene expression (MIDGE) vectors for DNA vaccination. MIDGE are linear, covalently-closed vectors containing all the essential information for gene expression and none of the non-essential and potentially dangerous plasmid backbone sequences. MIDGE vectors can also be chemically modified on both ends at defined positions allowing targeting of the DNA to specific cell types or cellular compartments. Immunisation of mice with simple and end-modified MIDGE vectors showed that they are efficacious tools to generate and/or manipulate antigen-specific immune responses.

The Effect of Chewing Urea-Containing Gum on Plaque Acidogenic and Alkaligenic Parameters

The aim of this double-blind crossover study was to determine the effect of chewing urea-containing gum on selected microbiological plaque properties. Eleven subjects chewed either urea-containing or urea-free placebo gum 3 times daily, each for 4 weeks, with at least a 4-week separation between regimes. After each chewing regime, plaque was sampled from all available surfaces, and inoculated into media indicative of acid or base production. In addition, interdental pH measurements were taken using touch Beetrode electrodes following sucrose and sorbitol mouthrinses, and sucrose mouthrinses followed by urea rinse, urea gum, or placebo gum. No significant differences in plaque acidogenic and alkaligenic properties were found between the urea and placebo gum regimes. Urea rinsing, urea gum and placebo gum all reduced the depth and duration of the pH fall following a sucrose mouthrinse. They also enhanced a rise in pH above the resting pH, but although urea gum produced a larger increase than placebo gum, the difference was not significant.

Acupuncture for induction of labour

BACKGROUND

This is one of a series of reviews of methods of cervical ripening and labour induction using standardised methodology. The use of complementary therapies is increasing and some women look to complementary therapies during pregnancy and childbirth to be used alongside conventional medical practice. Acupuncture involves the insertion of very fine needles into specific points of the body. The limited observational studies to date suggest acupuncture for induction of labour appears safe, has no known teratogenic effects, and may be effective. The evidence regarding the clinical effectiveness of this technique is limited.

OBJECTIVES

To determine the effects of acupuncture for third trimester cervical ripening or induction of labour.

SEARCH STRATEGY

The Cochrane Pregnancy and Childbirth Group trials register (February 2003), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 1, 2003), PubMed (1966 to present), CISCOM (1960 to present), EMBASE (1980 to present) and bibliographies of relevant papers.

SELECTION CRITERIA

Clinical trials comparing acupuncture used for third trimester cervical ripening or labour induction with placebo/no treatment or other methods listed above it on a predefined list of labour induction methods.

DATA COLLECTION AND ANALYSIS

A strategy was developed to deal with the large volume and complexity of trial data relating to labour induction. This involved a two-stage method of data extraction.

MAIN RESULTS

One trial of 56 women was included in the review. Data were not in a form that could be included in the meta-analysis.

REVIEWER'S CONCLUSIONS

There is a need for well-designed randomised controlled trials to evaluate the role of acupuncture to induce labour and for trials to assess clinically meaningful outcomes.

The TRAIL of Death

The TNF ligand family member termed TRAIL has been shown to induce apoptosis in a wide variety of transformed cell lines. The normal functions of this cytokine in vivo remain, however, relatively unknown. The complexity of this biological system has now increased unexpectedly with the identification of four distinct receptors for TRAIL, two of which have cytoplasmic death domains. This review will describe the known biological effects of TRAIL, as well as the structure and possible functions of its recently identified receptors.

How much science is there in injury prevention and control?

OBJECTIVES

To determine what proportion of research papers at an injury prevention conference reported an evaluation.

METHODS

A random sample of 250 abstracts from the 6th World Conference on Injury Prevention and Control were classified by methodological type. Those that described any evaluation were further subdivided by whether the evaluation was of process or if it used an intermediate or "true" outcome.

RESULTS

Of 250 abstracts, 20 (8%; 95% confidence interval 5.0% to 12.1%) showed evaluations with intermediate or true outcomes. Research designs were weak. Among the 20 reports, none was a randomized trial and only two conducted a before and after study with control group. The remaining 17 used before-after or "after only" designs.

CONCLUSION

The conference papers included few evaluations. To ensure that resources are best used, those in the injury prevention field must increase their use of rigorous evaluation.

Complementary and alternative therapies for pain management in labour

BACKGROUND

Many women would like to avoid pharmacological or invasive methods of pain management in labour and this may contribute towards the popularity of complementary methods of pain management. This review examined currently available evidence supporting the use of alternative and complementary therapies for pain management in labour.

OBJECTIVES

To examine the effectiveness of complementary and alternative therapies for pain management in labour on maternal and perinatal morbidity.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register (July 2002), the Cochrane Controlled Trials Register (The Cochrane Library Issue 2, 2002), MEDLINE (1966 to July 2002), EMBASE (1980 to July 2002) and CINAHL (1980 to July 2002).

SELECTION CRITERIA

The inclusion criteria included published and unpublished randomised controlled trials comparing complementary and alternative therapies with placebo, no treatment or pharmacological forms of pain management in labour. All women whether primiparous or multiparous, and in spontaneous or induced labour, in the first and second stage of labour were included.

DATA COLLECTION AND ANALYSIS

Meta-analysis was performed using relative risks for dichotomous outcomes and weighted mean differences for continuous outcomes. The outcome measures were maternal satisfaction, use of pharmacological pain relief and maternal and neonatal adverse outcomes.

MAIN RESULTS

Seven trials involving 366 women and using different modalities of pain management were included in this review. The trials included one involving acupuncture (n = 100), one involving audio-analgesia (n = 25), one involving aromatherapy (n = 22), three trials of hypnosis (n = 189) and one trial of music (n = 30). The trial of acupuncture decreased the need for pain relief (relative risk (RR) 0.56, 95% confidence interval (CI) 0.39 to 0.81). Women receiving hypnosis were more satisfied with their pain management in labour compared with controls (RR 2.33, 95% CI 1.55 to 4.71). No differences were seen for women receiving aromatherapy, music or audio analgesia.

REVIEWER'S CONCLUSIONS

Acupuncture and hypnosis may be beneficial for the management of pain during labour. However, few complementary therapies have been subjected to proper scientific study and the number of women studied is small.

The effect of dietary selenium source and level on the uptake of selenium by developing chick embryos

We studied the effect of dietary source (organic or inorganic) and level of Se on the Se uptake of chick embryos. After receiving a low-Se diet for 16 wk, 126 Leghorn laying hens were randomly assigned to one of seven dietary treatments. Treatments consisted of feeding a low-Se basal diet alone or with one of three levels of added Se (0.1,0.2, or 0.3 mg/kg Se) supplied by sodium selenite or Se-enriched yeast. Fertile eggs were collected after 33 d of feeding the experimental diets. Eggs were subjected to no incubation or incubation for 5, 10, 15, or 20 d. Non-incubated eggs were separated, and the yolk and albumen were assayed separately for Se. Incubated eggs were separated into the embryo and extra-embryonic portions, which were assayed separately for Se. Se concentrations of the yolk and albumen were significantly different among dietary treatments. Compared with eggs from hens fed sodium selenite, yolk and albumen Se concentrations were higher in eggs from hens fed Se yeast. Embryonic and extra-embryonic Se concentrations were higher in eggs from hens fed Se yeast than eggs from hens fed sodium selenite. The largest increase in embryonic Se concentration was observed during Days 10 to 15 of incubation. It was concluded that Se source and dietary inclusion level influenced the Se concentration of portions of developing embryonated eggs and that embryonic Se concentration changed during incubation.

The importance of timing: the varying impact of childhood and adolescent maltreatment on multiple problem outcomes

A substantial body of literature suggests that childhood maltreatment is related to negative outcomes during adolescence, including delinquency, drug use, teenage pregnancy, and school failure. There has been relatively little research examining the impact that variation in the developmental stage during which the maltreatment occurs has on these relationships, however. In this paper, we reassess the impact of maltreatment on a number of adverse outcomes when developmentally specific measures of maltreatment-maltreatment that occurs only in childhood, only in adolescence, or in both childhood and adolescence-are considered. Data are drawn from the Rochester Youth Development Study, a broad-based longitudinal study of adolescent development. The analysis examines how maltreatment affects delinquency, drug use, alcohol-related problems, depressive symptoms, teen pregnancy. school dropout, and internalizing and externalizing problems during adolescence. We also examine whether the type of maltreatment experienced at various developmental stages influences the outcomes. Overall, our results suggest that adolescent and persistent maltreatment have stronger and more consistent negative consequences during adolescence than does maltreatment experienced only in childhood.

Inhaled steroids as prophylaxis for delayed pulmonary toxicity syndrome in breast cancer patients undergoing high-dose chemotherapy and autologous stem cell transplantation

PURPOSE

To evaluate the efficacy of inhaled fluticasone propionate (Flovent) as prophylaxis against delayed pulmonary toxicity syndrome (DPTS) and decline in pulmonary function in breast cancer patients undergoing high-dose chemotherapy with the conditioning regimen of cyclophosphamide, cisplatin, and carmustine (CPB) followed by autologous stem cell transplantation (ASCT).

PATIENTS AND METHODS

Sixty-three consecutive patients with multinode-positive or metastatic breast cancer undergoing high-dose chemotherapy with CPB and ASCT who were treated at the Duke University Adult Bone Marrow Transplant Program. All patients were started on inhaled fluticasone propionate, 880 microg every 12 hours, for 12 weeks from the start date of their CPB conditioning regimen. Pulmonary function tests (PFTs) with a single-breath diffusing capacity of carbon monoxide (DLCO) were performed pre-ASCT as well as approximately 6 and 12 weeks post-ASCT. DPTS was defined as follows: (1) development of a nonproductive cough and dyspnea with or without fever, plus a fall in DLCO to less than 60% predicted; or (2) decline in DLCO to less than 50% predicted with or without symptoms.

RESULTS

Pulmonary function tests were done on all patients pre-ASCT, on 56 of the 63 patients at a median of 44 days (range, 25 to 73 days) post-ASCT, and on 51 of the 63 patients at a median of 96 days (range, 50 to 190 days) post-ASCT. The PFTs showed an average of an 8% (+/-26%) and 21% (+/-22%) decline in DLCO. These declines compare favorably with our historical control group of 45 consecutive breast cancer patients undergoing ASCT with CPB as a conditioning regimen, who experienced average declines in DLCO of 29% (+/-18%) (P < .001) and 33% (+/-18%) (P < .001) at comparable time periods post-ASCT. Delayed pulmonary toxicity syndrome occurred in 35% of treated patients compared to 73% of the historical controls (P = .0003). No patients died of DPTS or pulmonary problems, and there were no fungal pneumonias.

CONCLUSION

Inhaled fluticasone propionate may decrease the incidence of DPTS in patients treated with CPB as a conditioning regimen for ASCT, as well as help to preserve pulmonary function as measured by DLCO. These results are worthy of further study in a randomized clinical trial.

Are alpha-gliadins glycosylated?

Alpha-gliadins isolated by carboxymethylcellulose chromatography contain noncovalently bound glucose probably due to contaminating proteoglycans and to material shed from the column. Traces of carbohydrate remain strongly bound to alpha-gliadins even after harsh denaturation, but our results indicate alpha-gliadins are not glycoproteins. Suggestions that gliadins are glycoproteins are probably due to contamination with this glucose and the presence of these proteoglycans.

Transcutaneous electrical nerve stimulation and acupuncture for primary dysmenorrhoea

BACKGROUND

Dysmenorrhoea is the occurrence of painful menstrual cramps of the uterus. Medical therapy for dysmenorrhoea commonly consists of nonsteroidal anti-inflammatory drugs or the oral contraceptive pill both of which work by reducing myometrial (uterine muscle) activity. However, these treatments are accompanied by a number of side effects, making an effective non-pharmacological method of treating dysmenorrhoea of potential value. Transcutaneous electrical nerve stimulation (TENS) is a treatment that has been shown to be effective for pain relief in a variety of conditions. Electrodes are placed on the skin and electric current applied at different pulse rates (frequencies) and intensities is used to stimulate these areas so as to provide pain relief. In dysmenorrhoea. TENS is thought to work by alteration of the body's ability to receive or perceive pain signals rather than by having a direct effect on the uterine contractions. Acupuncture may also be indicated as a useful, non-pharmacological method for treating dysmenorrhoea. Acupuncture is thought to excite receptors or nerve fibres which, through a complicated interaction with mediators such as serotonin and endorphins, blocks pain impulses. Acupuncture typically involves penetration of the skin by fine, solid metallic needles, which are manipulated manually or by electrical stimulation.

OBJECTIVES

To determine the effectiveness of high and low frequency transcutaneous electrical nerve stimulation and acupuncture when compared to each other, placebo, no treatment, or medical treatment for primary dysmenorrhoea.

SEARCH STRATEGY

Electronic searches of the Cochrane Menstrual Disorders and Subfertility Group Register of controlled trials, CCTR (Cochrane Library Issue 3, 2001), MEDLINE, EMBASE, CINAHL, Bio extracts, PsycLIT and SPORTDiscus were performed in August 2001 to identify relevant randomised controlled trials (RCTs). The Cochrane Complementary Medicine Field's Register of controlled trials (CISCOM) was also searched. Attempts were also made to identify trials from the UK National Research Register, the Clinical Trial Register and the citation lists of review articles and included trials. In most cases, the first or corresponding author of each included trial was contacted for additional information.

SELECTION CRITERIA

The inclusion criteria were randomised controlled trials of transcutaneous electrical nerve stimulation and acupuncture that compared these treatments to each other, placebo, no treatment, or medical treatment for primary dysmenorrhoea. Exclusion criteria were: mild, infrequent or secondary dysmenorrhoea and dysmenorrhoea associated with an IUD.

DATA COLLECTION AND ANALYSIS

Nine RCTs were identified that fulfilled the inclusion criteria for this review, seven involving TENS, one acupuncture, and one both treatments. Quality assessment and data extraction were performed independently by two reviewers. Meta analysis was performed using odds ratios for dichotomous outcomes and weighted mean differences for continuous outcomes. Data unsuitable for meta-analysis was reported as descriptive data and was also included for discussion. The outcome measures were pain relief (dichotomous, visual analogue scales, descriptive), adverse effects, use of analgesics additional to treatment and absence from work or school.

MAIN RESULTS

Overall high frequency TENS was shown to be more effective for pain relief than placebo TENS. Low frequency TENS was found to be no more effective in reducing pain than placebo TENS. There were conflicting results regarding whether high frequency TENS is more effective than low frequency TENS. One small trial showed acupuncture to be significantly more effective for pain relief than both placebo acupuncture and two no treatment control groups.

REVIEWER'S CONCLUSIONS

High frequency TENS was found to be effective for the treatment of dysmenorrhoea by a number of small trials. The minor adverse effects reported in one trial requires further investigation. There is insufficient evidence to determine the effectiveness of low frequency TENS in reducing dysmenorrhoea. There is also insufficient evidence to determine the effectiveness of acupuncture in reducing dysmenorrhoea, however a single small but methodologically sound trial of acupuncture suggests benefit for this modality.

Sex determination in the chicken embryo

The chicken embryo represents a suitable model for studying vertebrate sex determination and gonadal sex differentiation. While the basic mechanism of sex determination in birds is still unknown, gonadal morphogenesis is very similar to that in mammals, and most of the genes implicated in mammalian sex determination have avian homologues. However, in the chicken embryo, these genes show some interesting differences in structure or expression patterns to their mammalian counterparts, broadening our understanding of their functions. The novel candidate testis-determining gene in mammals, DMRT1, is also present in the chicken, and is expressed specifically in the embryonic gonads. In chicken embryos, DMRT1 is more highly expressed in the gonads and Müllerian ducts of male embryos than in those of females. Meanwhile, expression of the orphan nuclear receptor, Steroidogenic Factor 1 (SF1) is up-regulated during ovarian differentiation in the chicken embryo. This contrasts with the expression pattern of SF1 in mouse embryos, in which expression is down-regulated during female differentiation. Another orphan receptor initially implicated in mammalian sex determination, DAX1, is poorly conserved in the chicken. A chicken DAX1 homologue isolated from a urogenital ridge library lacked the unusual DNA-binding motif seen in mammals. Chicken DAX1 is autosomal, and is expressed in the embryonic gonads, showing somewhat higher expression in female compared to male gonads, as in mammals. However, expression is not down-regulated at the onset of testicular differentiation in chicken embryos, as occurs in mice. These comparative data shed light on vertebrate sex determination in general.

A novel TNF receptor family member binds TWEAK and is implicated in angiogenesis

TWEAK is a member of the TNF ligand family that induces angiogenesis in vivo. We report cloning of a receptor for TWEAK (TweakR) from a human umbilical vein endothelial cell (HUVEC) library. The mature form of TweakR has only one hundred and two amino acids and six cysteine residues in its extracellular region. Five different assays demonstrate TWEAK-TweakR binding, and the interaction affinity constant (Kd) is within a physiologically relevant range of 2.3 +/- 0.1 nM. The TweakR cytoplasmic domain binds TRAFs 1, 2, and 3. Cross-linking of TweakR induces HUVEC growth, and mRNA levels are upregulated in vitro by a variety of agents and in vivo following arterial injury. Soluble TweakR inhibits endothelial cell migration in vitro and corneal angiogenesis in vivo.

Hydrolysis of tert-butyl methyl ether (MTBE) in dilute aqueous acid

tert-Butyl methyl ether (MTBE) is generally considered to be resistant to chemical transformation in aqueous solution. This lack of reactivity has led to concerns of the long-term impacts of MTBE in groundwater. Although hydrolysis in the presence of strong acids has been recognized as a mechanism for MTBE transformation, it has been discounted as a significant reaction under environmental conditions. In this study, we have examined the fate of MTBE and other ether oxygenates under moderately acidic conditions (> or=pH 1). The results demonstrate that MTBE is sensitive to acid-catalyzed hydrolysis reaction that generates tert-butyl alcohol (TBA) and methanol as products. The reaction is first-order with respect to the concentration of MTBE and hydronium ion with a second-order rate constant of about 0.9 x 10(-2) M(-1) h(-1) at 26 degrees C. Commercially available acidic ion-exchange resins were also shown to catalyze the hydrolysis of MTBE at near neutral pH. Pseudo-first-order rate constants were observed to be as high as 0.03 h(-1) at 25 degrees C and 0.12 h(-1) at 35 degrees C. These findings are discussed in terms of their possible implications for the treatment and environmental fate of MTBE and other gasoline oxygenates.

Inhibition of TRAIL-induced apoptosis and forced internalization of TRAIL receptor 1 by adenovirus proteins

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) induces apoptosis through two receptors, TRAIL-R1 (also known as death receptor 4) and TRAIL-R2 (also known as death receptor 5), that are members of the TNF receptor superfamily of death domain-containing receptors. We show that human adenovirus type 5 encodes three proteins, named RID (previously named E3-10.4K/14.5K), E3-14.7K, and E1B-19K, that independently inhibit TRAIL-induced apoptosis of infected human cells. This conclusion was derived from studies using wild-type adenovirus, adenovirus replication-competent mutants that lack one or more of the RID, E3-14.7K, and E1B-19K genes, and adenovirus E1-minus replication-defective vectors that express all E3 genes, RID plus E3-14.7K only, RID only, or E3-14.7K only. RID inhibits TRAIL-induced apoptosis when cells are sensitized to TRAIL either by adenovirus infection or treatment with cycloheximide. RID induces the internalization of TRAIL-R1 from the cell surface, as shown by flow cytometry and indirect immunofluorescence for TRAIL-R1. TRAIL-R1 was internalized in distinct vesicles which are very likely to be endosomes and lysosomes. TRAIL-R1 is degraded, as indicated by the disappearance of the TRAIL-R1 immunofluorescence signal. Degradation was inhibited by bafilomycin A1, a drug that prevents acidification of vesicles and the sorting of receptors from late endosomes to lysosomes, implying that degradation occurs in lysosomes. RID was also shown previously to internalize and degrade another death domain receptor, Fas, and to prevent apoptosis through Fas and the TNF receptor. RID was shown previously to force the internalization and degradation of the epidermal growth factor receptor. E1B-19K was shown previously to block apoptosis through Fas, and both E1B-19K and E3-14.7K were found to prevent apoptosis through the TNF receptor. These findings suggest that the receptors for TRAIL, Fas ligand, and TNF play a role in limiting virus infections. The ability of adenovirus to inhibit killing through these receptors may prolong acute and persistent infections.

Do poison center triage guidelines affect healthcare facility referrals?

BACKGROUND

The purpose of this study was to determine the extent to which poison center triage guidelines influence healthcare facility referral rates for acute, unintentional acetaminophen-only poisoning and acute, unintentional adult formulation iron poisoning.

METHODS

Managers of US poison centers were interviewed by telephone to determine their center's triage threshold value (mg/kg) for acute iron and acute acetaminophen poisoning in 1997. Triage threshold values and healthcare facility referral rates were fit to a univariate logistic regression model for acetaminophen and iron using maximum likelihood estimation.

RESULTS

Triage threshold values ranged from 120-201 mg/kg (acetaminophen) and 16-61 mg/kg (iron). Referral rates ranged from 3.1% to 24% (acetaminophen) and 3.7% to 46.7% (iron). There was a statistically significant inverse relationship between the triage value and the referral rate for acetaminophen (p < 0.001) and iron (p = 0.0013). The model explained 31.7% of the referral variation for acetaminophen but only 4.1% of the variation for iron.

CONCLUSION

There is great variability in poison center triage values and referral rates for iron and acetaminophen poisoning. Guidelines can account for a meaningful proportion of referral variation. Their influence appears to be substance dependent. These data suggest that efforts to determine and utilize the highest, safe, triage threshold value could substantially decrease healthcare costs for poisonings as long as patient medical outcomes are not compromised.

High-efficiency retroviral transduction of fetal liver CD38-CD34++ cells: implications for in utero and ex utero gene therapy

OBJECTIVES

Defining methods for the efficient transduction of fetal stem cells could lead to novel fetal therapies for blood cell disorders and other birth defects. In this study, we analyzed the effects of various parameters on the retroviral transduction of primitive hematopoietic progenitors/stem cells isolated from fetal liver.

METHODS

Candidate stem cells were isolated by fluorescence-activated cell sorting from midtrimester human livers based on the phenotype CD38-CD34++lineage- (lineage = glycophorin A, CD3, CD14, CD19, CD20 and CD56). A murine retroviral vector with a truncated human low-affinity nerve growth factor receptor (Delta NGFR) gene was used to transduce the candidate stem cells. Marker gene expression was monitored by flow cytometry using an anti-NGFR mAb. Candidate stem cells were transduced immediately after isolation or after up to 4 days of culture in serum-deprived medium containing the growth factors kit ligand and granulocyte-macrophage colony-stimulating factor. The effects on transduction efficiency of the addition of 4 microg/ml protamine sulfate and/or centrifugation to concentrate the candidate stem cells and virus were tested. After transduction, the cells were expanded for 10-21 days before determining the frequency of NGFR+ cells among the different hematopoietic progeny.

RESULTS

Efficient transduction of candidate stem cells, at an average rate of 46%, was achieved after 3 days of culture with a single exposure to virus. Longer than 3 days of culture or repeated exposure to viral supernatant did not significantly improve the rate of transduction. The use of centrifugation at 1,200 g for 1 h and the addition of protamine sulfate during the transduction procedure were critical to achieving a high rate of transduction. Marker gene expression was observed on the progeny of the transduced cells in conjunction with CD34 (progenitors), glycophorin A (erythrocytes), CD14 (monocytes), CD15 (granulocytes) and CD41 (megakaryocytes).

CONCLUSIONS

This study demonstrates that the efficient transduction of fetal candidate stem cells can be achieved under defined culture conditions using a retroviral vector. These results encourage further examination of in utero and ex utero gene therapy as a means of treating birth defects.

Folate-binding triggers the activation of folylpolyglutamate synthetase

Folic acid is an essential vitamin for normal cell growth, primarily through its central role in one-carbon metabolism. Folate analogs (antifolates) are targeted at the same reactions and are widely used as therapeutic drugs for cancer and bacterial infections. Effective retention of folates in cells and the efficacy of antifolate drugs both depend upon the addition of a polyglutamate tail to the folate or antifolate molecule by the enzyme folylpolyglutamate synthetase (FPGS). The reaction mechanism involves the ATP-dependent activation of the free carboxylate group on the folate molecule to give an acyl phosphate intermediate, followed by attack by the incoming L-glutamate substrate. FPGS shares a number of structural and mechanistic details with the bacterial cell wall ligases MurD, MurE and MurF, and these enzymes, along with FPGS, form a subfamily of the ADP-forming amide bond ligase family. High-resolution crystallographic analyses of binary and ternary complexes of Lactobacillus casei FPGS reveal that binding of the first substrate (ATP) is not sufficient to generate an active enzyme. However, binding of folate as the second substrate triggers a large conformational change that activates FPGS and allows the enzyme to adopt a form that is then able to bind the third substrate, L-glutamate, and effect the addition of a polyglutamate tail to the folate.

Burkholderia pseudomallei virulence: definition, stability and association with clonality

Clinical presentations of melioidosis, caused by Burkholderia pseudomallei are protean, but the mechanisms underlying development of the different forms of disease remain poorly understood. In murine melioidosis, the level of virulence of B. pseudomallei is important in disease pathogenesis and progression. In this study, we used B. pseudomallei-susceptible BALB/c mice to determine the virulence of a library of clinical and environmental B. pseudomallei isolates from Australia and Papua New Guinea. Among 42 non-arabinose-assimilating (ara(-)) isolates, LD(50) ranged from 10 to > 10(6) CFU. There were numerous correlations between virulence and disease presentation in patients; however, this was not a consistent observation. Virulence did not correlate with isolate origin (i.e. clinical vs environmental), since numerous ara(-) environmental isolates were highly virulent. The least virulent isolate was a soil isolate from Papua New Guinea, which was arabinose assimilating (ara(+)). Stability of B. pseudomallei virulence was investigated by in vivo passage of isolates through mice and repetitive in vitro subculture. Virulence increased following in vivo exposure in only one of eight isolates tested. In vitro subculture on ferric citrate-containing medium caused attenuation of virulence, and this correlated with changes in colony morphology. Pulsed-field gel electrophoresis and randomly amplified polymorphic DNA typing demonstrated that selected epidemiologically related isolates that had variable clinical outcomes and different in vivo virulence were clonal strains. No molecular changes were observed in isolates after in vivo or in vitro exposure despite changes in virulence. These results indicate that virulence of selected B. pseudomallei isolates is variable, being dependent on factors such as iron bioavailability. They also support the importance of other variables such as inoculum size and host risk factors in determining the clinical severity of melioidosis.

A comparison of two methods of assessing disease activity in the joints

BACKGROUND

Considerable debate has occurred concerning the utility of different methods of obtaining joint counts and their usefulness in predicting outcomes in persons with rheumatoid arthritis.

OBJECTIVE

The purpose of this study was to compare two methods of assessing disease activity in the joints (clinician joint count, self-reported joint count), and to compare their relative utility in predicting two methods of assessing outcomes (self-reported ratings of impairment and pain, objective performance index) with and without controlling for negative affectivity.

METHOD

Data for this study were obtained during home visits from 185 persons diagnosed with rheumatoid arthritis. Individuals completed a series of self-report measures including the joint count. Trained research assistants completed a 28-joint count and timed participants on a series of measured performance activities (e.g., grip strength, pinch strength, walk time).

RESULTS

The self-report joint count was highly correlated with the clinician joint count and also accounted for as much, if not more, variance in the subjective outcome measures than did clinician assessments. Both types of indicators predicted unique variance in the objective performance index.

CONCLUSIONS

For most research purposes, measures such as self-report joint counts have sufficient validity to be used in place of more costly clinician assessment of joint counts.