OBJECTIVE

The major aims were to evaluate responsiveness and clinical/research applicability of the Revised Oswestry Disability Questionnaire (ODQ) and the Dallas Pain Questionnaire (DPQ). Construct and content validity were assessed. Patient characteristics and outcomes were also documented.

METHODS

Longitudinal observational study.

METHODS

College outpatient clinics.

METHODS

Six hundred sixty-three consecutive new patients accepted for treatment of low back pain (LBP) at the clinics over a 1-yr period, age 18 or older.

METHODS

Treatment of low back pain by senior interns under the supervision of staff clinicians.

METHODS

ODQ and DPQ administered at baseline, 2 wk, 1 month, and monthly up to 6 months. Responsiveness: mean standardized change score (delta' = mudif/sigma dif), relative efficiency ([RE = delta' ODQ/delta DPQ']2), and improvement rates (IR). Applicability: instrument completion rates. Construct validity: correlation with VAS for pain intensity.

RESULTS

ODQ responsiveness was generally consistent over time (delta' = .70-.83) and negligibly better than the DPQ activities of daily living scale (RE = 1.00-1.35); most patients self-reporting improvement showed positive outcomes (IR = 97%). For large samples (n>> 100): delta' = .47-.63 and IR = 81% for the DPQ work/leisure scale; delta' = .17-.40 and IR = 54% for the DPQ anxiety/depression and social dimensions. Completion rates: 65%-78% of all instruments; 81%-100% of individual scales. Construct validity: r = .44-.68 for the ODQ, DPQ activities of daily living, and DPQ work/leisure scales; r = .20-.40 for the anxiety/depression scale.

CONCLUSIONS

The ODQ and the activities of daily living and work/leisure scales from the DPQ appear appropriate for monitoring LBP patients returning for care to chiropractic teaching clinics. The social and anxiety/depression dimensions of the DPQ do not appear to be responsive in this population. The latter scale may be unsuitable on the grounds of misinterpretations.

OBJECTIVE

The Multidimensional Health Locus of Control (MHLC) scales are widely used to measure beliefs about determinants of persons' health. We evaluated the scales over the largest-ever disease-specific sample of subjects using a combined-method psychometric approach.

METHODS

We performed a secondary analysis of data from 1,206 subjects from three osteoarthritis studies, using Rasch analysis and confirmatory factor analysis simultaneously. Differential item functioning (DIF) by gender and data source, scale dimensionality, and item fit were examined. The Rasch model fit the data if Rasch residual principal components analysis (PCA) corroborated three distinct dimensions and item fit statistics fell between 0.80 and 1.20. The confirmatory factor (CFA) model fit the data if factor loadings exceeded 0.50 for all items.

RESULTS

DIF by gender or data source was not materially evident for any items. PCA supported existence of three dimensions in the data. Both Rasch and CFA models fit the data for 16 items; two items were detected as misperforming. When these items were removed, fit of both models improved.

CONCLUSIONS

Results of this large-sample evaluation of the MHLC scales corroborated earlier findings that removal of certain items improves the scales. The combined Rasch-CFA approach provided better insight to scale performance problems than either method alone provided.

The Center for Epidemiological Studies-Depression (CES-D) scale is a widely used measure of depressive symptoms, but its psychometric properties have not been adequately evaluated among adults with HIV/AIDS. This study used an item response theory approach (Rasch analysis) to evaluate the CES-D's validity and reliability in relation to key demographic and clinical variables in adults with HIV/AIDS. A convenience sample of 347 adults with HIV/AIDS (231 males, 93 females, and 23 transgenders; age range 22-77 years) completed the CES-D. A Rasch model application was used to analyze the CES-D's rating scale functioning, internal scale validity, person-response validity, person-separation validity, internal consistency, differential item functioning (DIF), and differential test functioning. CES-D scores were generally high and associated with several demographic and clinical variables. The CES-D distinguished 3 distinct levels of depression and had acceptable internal consistency but lacked unidimensionality, five items demonstrated poor fit to the model, 15% of the respondents demonstrated poor fit, and eight items demonstrated DIF related to gender, race, or AIDS diagnosis. Removal of misfitting items resulted in minimal improvement in the CES-D's substantive and structural validity. CES-D scores should be interpreted with caution in adults with HIV/AIDS, particularly when comparing scores across gender and racial groups.

In bacteria, the FtsK/Xer/dif (chromosome dimer resolution site) system is essential for faithful vertical genetic transmission, ensuring the resolution of chromosome dimers during their segregation to daughter cells. This system is also targeted by mobile genetic elements that integrate into chromosomal dif sites. A central question is thus how Xer/dif recombination is tuned to both act in chromosome segregation and stably maintain mobile elements. To explore this question, we focused on pathogenic Neisseria species harboring a genomic island in their dif sites. We show that the FtsK DNA translocase acts differentially at the recombination sites flanking the genomic island. It stops at one Xer/dif complex, activating recombination, but it does not stop on the other site, thus dismantling it. FtsK translocation thus permits cis discrimination between an endogenous and an imported Xer/dif recombination complex.

OBJECTIVE

Differentiation-inducing factors (DIFs) are chlorinated alkylphenones found in the cellular slime mold Dictyostelium discoideum. DIF derivatives exhibit antiproliferative activities and promote glucose consumption in mammalian cells in vitro. In this study, we assessed the ability of DIFs to regulate the immune system and investigated their mechanisms of action.

METHODS

We examined the effects of 30 DIF derivatives on concanavalin A-induced IL-2 production (CIIP) in Jurkat T-cells. We also examined the effects of some DIF derivatives on the activity of AP-1 (activator protein-1), NFAT (nuclear factor of activated T-cells), and NFkappaB (nuclear factor kappa B), which are transcription factors required for CIIP.

RESULTS

Of the derivatives tested, some compounds suppressed CIIP as well as the known immunosuppressants cyclosporine A and FK506. A reporter gene assay revealed that 4 DIF derivatives tested suppressed CIIP, at least in part, by inhibiting the activity of AP-1, NFAT, and/or NFkappaB. Unlike cyclosporine A and FK506, the DIF derivatives had little effect on concanavalin A-induced interferon-gamma production in Jurkat cells.

CONCLUSIONS

The present results suggest that DIF derivatives could be developed as novel immunosuppressive drugs.

The aim of this study was to evaluate the prevalence of suicide in Turkish male substance dependents, and to investigate the relationship of suicide attempt history with childhood abuse and neglect, alexithymia, and temperament and character dimensions of personality. Participants were 154 consecutively admitted male substance dependents. Patients were investigated with the Childhood Abuse and Neglect Questionnaire, Toronto Alexithymia Scale (TAS-20) and Temperament and Character Inventory (TCI). Among substance-dependent patients, 28.6% was considered a group with suicide attempt history (SAH). Current age was lower and rate of being single was higher in the group with SAH. There were no significant differences between groups in terms of employment, educational status and duration of education. Rates of physical, emotional abuse and neglect, self-mutilation and being alexithymic were higher and ages at first substance use and regular substance use were lower in the group with SAH. Mean scores of "difficulty in identifying feelings" (DIF) and "difficulty in describing feelings" (DDF) subscale EOT of the TAS-20 were higher in the SAH group. Among temperament and character dimensions of the TCI, only "Self-directedness" and "Cooperativeness" were lower in SAH and there were no significant differences between groups in terms of other subscales. Age and Self-directedness score of TCI were determinants for suicide attempt. In particular, young drug users with low Self-directedness scores could be the target population in order to prevent suicidal behavior. This study also suggests that in substance-dependent patients, in the background of all suicidal behavior, childhood abuse and neglect must be evaluated.

BACKGROUND

The Positive Mental Health (PMH) instrument was developed and validated to assess the level of PMH and its six dimensions in a multi-ethnic general population sample. This cross-sectional study examines the psychometric properties of the instrument for assessing the level of PMH among help-seeking patients with mental disorders.

METHODS

The PMH instrument was tested among 360 out-patients with schizophrenia, depression or anxiety spectrum disorders, seeking treatment at a tertiary psychiatric hospital and its affiliated clinics in Singapore. All participants completed the PMH instrument along with measures of life satisfaction, mental and overall health and happiness. Reliability (internal consistency), construct (Exploratory Structural Equation Modeling (ESEM)) and criterion (convergent and divergent) validity of the PMH instrument were tested in this population. Items were also tested for item response theory and differential item functioning (IRT-DIF).

RESULTS

ESEM on the PMH instrument showed good fit with the model reflecting six factors (general coping, personal growth and autonomy, spirituality, interpersonal skills, emotional support, and global affect). Internal consistency was high (Cronbach's alpha >0.85) for the instrument and its six subscales. The PMH instrument fulfilled expected correlations with related constructs and demonstrated adequate item discrimination and difficulty estimates; however, significant DIF was noted for few items for age, gender and ethnicity groups.

CONCLUSIONS

The PMH instrument is a reliable and valid instrument for measuring PMH dimensions in patients with mental disorders. Further studies in larger samples are needed to assess the impact of DIF on PMH scores. The implications for the shift in focus from just the negative aspects of mental disorders to including positive components in the assessment of patients with mental disorders are immense, and can be applied in routine mental health practice and policy making.

BACKGROUND

Differential Item Functioning (DIF) is investigated to ensure that each item displays a consistent pattern of responses irrespective of the characteristics of the respondents. Assessing DIF helps to understand the nature of instruments, to assess the quality of a measure and to interpret results. This study aimed to examine whether the items of the Quality of Life Enjoyment and Satisfaction Questionnaire-Short Form (Q-LES-Q-SF) and Short-Form 12 (SF-12) exhibit DIF.

METHODS

A total of 124 outpatients diagnosed with substance dependence participated in a cross-sectional, multicenter study. In addition to the Q-LES-Q-SF and SF-12 results, demographic data such as age, sex, type of substance dependence and education level were collected. Rasch analysis was conducted (using RUMM2020 software) to assess DIF of the Q-LES-Q-SF and SF-12 items.

RESULTS

For SF-12, significant age-related uniform DIF was found in two of the 12 items, and sex-related DIF was found in one of the 12 items. All of the observed DIF effects in SF-12 were found among the mental health items. Three items showed DIF on the Q-LES-Q-SF; however, the impact of DIF item on the delta score calculation for the comparisons of self-reported health status between the groups was minimal in the SF-12 and small in the Q-LES-Q-SF.

CONCLUSIONS

These results indicated that no major measurement bias affects the validity of the self-reported health status assessed using the Q-LES-Q-SF or SF-12. Thus, these questionnaires are largely robust measures of self-reported health status among substance users.

Two well-described elements of the immune response of insects include encapsulation of metazoan parasites (blood-cell-mediated) and the production of antibacterial peptides (humoral and/or cellular). However, the possible functional interrelationship between cellular encapsulation and antibacterial responses, and the extent to which the two components may be co-regulated, are poorly understood. We used a novel approach involving strains of Drosophila resistant (R) or susceptible (S) to the wasp parasitoid Leptopilina boulardi to study the expression of three genes involved in the antibacterial response: Dorsal-related immunity factor (Dif), Cecropin (CecA1) and Diptericin (Dip). Both S and R strains produced high levels of all antibacterial transcripts upon bacterial injection. However, when parasitized the R strain showed no induction whilst the S strain did. This lack of antibacterial transcript induction in the parasitized R strain not only clarifies the separation of these two types of immune response but also raises the fascinating possibility of a link in their genetic regulation.

OBJECTIVE

The main purpose of this study was to demonstrate the relevance of testing indices concerning the psychosocial work environment by item bias or differential item functioning (DIF) analysis. Especially when the work environment for different groups is compared, this kind of construct validation is important. As exogenous variables gender, age, and occupational group were selected.

METHODS

Data were taken from a cross-sectional study of Danish employees aged 19-59 years (N=5940). The study was carried out in 1990 and followed-up in 1995.

RESULTS

Item bias was demonstrated in all indices when analyzed in relation to gender, age, and occupational groups of the total population. Item bias was much weaker or disappeared as the population was divided into main occupational groups and analyzed in relation to the same exogenous variables.

CONCLUSIONS

For a heterogeneous group of employees, gender, age, and occupational status are significant determinants of the response pattern in relation to indices of the psychosocial work environment. It was concluded that, if the psychosocial work environment for different groups is to be compared, indices should always be tested for item bias in relation to the exogenous variables included in the final analyses. Indices should only be used if there is no item bias. If such indices cannot be constructed, it is suggested that researchers either concentrate on constructing indices that are valid in subgroups or report results based on single-item analyses.

We describe a 7-year-old boy with dermatitis herpetiformis (DH) diagnosed on clinical and histologic evidence, negative direct immunofluorescence (DIF) findings for junctional IgA deposits in uninvolved skin, positive IgA endomysial and gliadin antibodies, and jejunal biopsy revealing a gluten-sensitive enteropathy. Treatment with dapsone led to the disappearance of cutaneous lesions and pruritus within 48 hours. Demonstration of IgA immune deposits in the dermal papillae has been the only acceptable criterion for the diagnosis of dermatitis herpetiformis. However, considering several reports in the literature of DH with a negative DIF and our own case, we believe that in the absence of the characteristic DIF pattern, one needs the combination of clinical, histologic, and immunologic data to support the diagnosis of DH. We also discuss recent developments in the diagnosis of DH.

OBJECTIVE

Bleaching can considerably reduce shear bond strength (SBS) of orthodontic brackets bonded with composite adhesives. Application of antioxidants is a method to reverse the negative effect of bleaching on composite-to-enamel bond. However, the efficacy of antioxidants in increasing the SBS of brackets bonded using resin-modified glass-ionomer cement (RMGIC) has not been studied, which was the aim of this study.

METHODS

Fifty freshly extracted human maxillary first premolars were bleached with 35% hydrogen peroxide (Pola Office Bleaching, SDI). Sodium ascorbate 10% was applied to the experimental specimens (n=25). All the specimens were etched with 37% phosphoric acid (Ivoclar/Vivadent) and bonded using RMGIC (Fuji Ortho LC, GC). The specimens were subjected to incubation (37°C, 24h) and thermocycling (1000 cycles, 5-55°C, dwell time = 1 min). The SBS was measured at 0.5 mm/min debonding crosshead speed. The adhesive remnant index (ARI) was scored under ×10 magni-fication. Data were analyzed using Mann-Whitney U test, one- and independent-samples t-test, and Fisher'sexact test (α=0.05).

RESULTS

The mean SBS of experimental and control groups were 11.97 ± 4.49 and 7.7 ± 3.19 MPa, respectively. The dif-ference was statistically significant (P=0.000 by t-test). SBS of both control (P=0.014) and experimental (P=0.000) groups were significantly higher than the minimum acceptable SBS of 6 MPa, according to one-sample t-test.

CONCLUSIONS

Application of ascorbic acid can guarantee a strong bond when RMGIC is to be used. However, RMGIC might tolerate the negative effect of bleaching with minimum SA treatments (or perhaps without treatments), which de-serves further studies.

The genomes of the 21 completely sequenced Thermococcales display a characteristic high level of rearrangements. As a result, the prediction of their origin and termination of replication on the sole basis of chromosomal DNA composition or skew is inoperative. Using a different approach based on biologically relevant sequences, we were able to determine oriC position in all 21 genomes. The position of dif, the site where chromosome dimers are resolved before DNA segregation could be predicted in 19 genomes. Computation of the core genome uncovered a number of essential gene clusters with a remarkably stable chromosomal position across species, in sharp contrast with the scrambled nature of their genomes. The active chromosomal reorganization of numerous genes acquired by horizontal transfer, mainly from mobile elements, could explain this phenomenon.

Differentiation-inducing factor-1 (DIF-1) is a morphogen that induces differentiation of DICTYOSTELIUM: Recently, DIF-1 has been shown to inhibit proliferation and induce differentiation in tumor cells, although the underlying mechanisms remain unknown. In this study, we examined the effects of DIF-1 on the proliferation and differentiation of vascular smooth muscle cells, to explore novel therapeutic strategies for atherosclerosis. DIF-1 nearly completely inhibited DNA synthesis and cell division in mitogen-stimulated cells. DIF-1 inhibited the phosphorylation of the retinoblastoma protein and the activities of cyclin-dependent kinase (Cdk) 4, Cdk6, and Cdk2, which phosphorylate the retinoblastoma protein. DIF-1 strongly suppressed the expression of cyclins D1, D2, and D3, as well as those of cyclins E and A, which normally began after that of the D-type cyclins. The mRNAs for the smooth muscle myosin heavy chains SM1 and SM2 were expressed in quiescent cells in primary culture, and these expression levels decreased after mitogenic stimulation. In the presence of DIF-1, the rate of the reduction was significantly decelerated. Moreover, the addition of DIF-1 to dedifferentiated cells induced the expressions of SM1 and SM2, accompanied by a reduction in the level of SMemb, a nonmuscle-type myosin heavy chain. Therefore, DIF-1 seemed to interrupt a very early stage of G(1) probably by suppressing the expressions of the D-type cyclins. Furthermore, this compound may prevent phenotypic modulation and induce differentiation of vascular smooth muscle cells.

Differentiation-inducing factor-1 and -2 (DIF-1 and DIF-2) are small lipophilic signal molecules that control both cell differentiation and chemotaxis in the cellular slime mold Dictyostelium discoideum. In this study, we examined the effects of four amide derivatives of DIF-1 on stalk cell differentiation and chemotaxis. The DIF derivatives differentially affected cell differentiation and chemotaxis, suggesting the possible existence of at least three receptors for DIFs: one receptor responsible for stalk cell induction, and two receptors responsible for chemotaxis modulation. Furthermore, our results indicate that DIF derivatives can be utilized to analyze the DIF-signaling pathways.

It has always been assumed that during development the embryo and fetus depend only on glycolysis for energy generation and that they do not oxidize fatty acids. Recently, however, we found abundant expression and activity of fatty acid oxidation (FAO) enzymes in the human embryo and fetus. In a search for FAO gene expression during development we came across two embryonic differentiation genes: differentiation defective (dif-1) and congested-like trachea (colt) of Caenorhabditis elegans and Drosophila melanogaster, respectively. Earlier studies showed that expression of these two genes is essential during developmental stages with high energy requirements. Both dif-1 and colt encode proteins with sequence similarity to the mitochondrial carnitine acylcarnitine carrier (CACT), which suggests that the DIF-1 and COLT proteins might be functional orthologues of CACT. To investigate this, we expressed both dif-1 and colt in Saccharomyces cerevisiae. Our results show that DIF-1 and COLT can functionally complement a yeast CACT deletion strain and thus function as carnitine acylcarnitine transporters. This finding is well in line with the recent observation that embryos are capable of oxidizing fatty acids and furthermore implies that FAO is essential during early embryonic development when the energy demand is high.

The major spore coat proteins of Dictyostelium discoideum are synthesized during the culmination stage of development. In an attempt to examine the regulatory mechanisms involved, spore coat protein synthesis by pseudoplasmodia harvested prior to culmination and incubated in submerged culture under various environmental conditions has been monitored. It is reported that the synthesis of spore coat proteins SP170, SP103, SP94, SP82, SP76, and SP55 is dependent upon the presence of a low-molecular-weight (Mr approx 100), heat-stable factor secreted by cells incubated at high density in buffer. Previous studies have implicated cyclic AMP, ammonia, and amino acids in spore cell differentiation. Partial purification of the spore coat protein inducing factor (SPIF), together with attempts to mimic its activity, indicate that SPIF is not identical with any of these molecules and it is probably also distinct from DIF and "fruit juice," two other factors which regulate the spore-stalk decision and the initiation of culmination, respectively, in D. discoideum. In addition to SPIF, the continued expression of the spore coat protein genes also requires that the integrity of the pseudoplasmodium be maintained. Unlike the expression of many other genes after aggregation, this latter requirement cannot be replaced by exogenous cyclic AMP. Termination of spore coat protein gene expression occurs despite the presence of excess exogenous SPIF and hence involves mechanisms other than the destruction or depletion of SPIF.

Slime moulds, such as Dictyostelium discoideum, have biochemical, physiological and probably developmental features in common with both plants and animals. During development separate Dictyostelium amoebae first aggregate into collecting centers to form small multicellular organisms which, in their slug form, can migrate over the substratum toward light. Eventually a slug culminates to form a fruiting body consisting of a cellular stalk supporting a mass of spores. Development is highly regulative, indicating that it is controlled by signalling between the cells. A number of diffusible signal molecules have been discovered, including cyclic AMP, the chemoattractant in aggregation, and DIF-1, a novel chlorinated phenyl alkanone, which acts as a specific inducer of stalk cell differentiation. The migrating slug contains three types of precursor cell: prespore, prestalk A and prestalk B cells. Differentiation of these cells from uncommitted amoebae can be brought about in cell cultures by cyclic AMP and DIF-1 acting in combination: cyclic AMP alone favours prespore, DIF-1 alone favours prestalk B, cyclic AMP and DIF-1 together favour prestalk A cell differentiation. There is evidence suggesting that these signals act in the same way in the intact aggregate. A cytoplasmic DIF-1 binding protein has been discovered, whose level increases as cells become sensitive to DIF-1 and which binds DIF-1 with an affinity and specificity suggestive of a receptor. At the same time, cells are able to inactivate DIF-1 by a metabolic pathway involving at least 12 metabolites. Metabolism may also serve to produce gradients of DIF-1 in the aggregate or other signal molecules from DIF-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Direct immunofluorescence (DIF) and the unlabelled antibody peroxidase--antiperoxidase (PAP) methods were compared on a quantitative basis with regard to visualization of IgA immunocytes and gastrin cells in human gastric mucosa, and secretin cells in canine duodenal mucosa. With both DIF and PAP, two serial sections from 13 biopsy specimens were evaluated for each cell type--thus keeping tissue preparation the same with both staining methods. The three cell types were well visualized regardless of method, and there was no significant difference between cell numbers recorded with the DIF or PAP. When blind duplicate counts were obtained with an interval of three weeks, comparisons of weighted differences and the Kendall's rank correlation test indicated good precision; the reproducibility of duplicate enumerations with each method was comparable to that between the two methods. It was concluded that DIF and PAP are equally applicable for studies of these three cell types under the conditions used in this investigation.

OBJECTIVE

The aim of this study was to improve the quality and applicability of the 6 Dutch scales of the Communication Profile for the Hearing Impaired (CPHI; Demorest & Erdman, 1986, 1987, 1988) using item response theory (IRT). IRT modeling can produce precise, valid, and relatively brief instruments, resulting in minimal response burden (Edelen & Reeve, 2006).

METHODS

We investigated (a) whether items fit to the graded response model (GRM; Samejima, 1969) using Stone and Zhang's (2003) procedure to test goodness of fit and (b) whether items showed differential item functioning (DIF) with the IRT log-likelihood ratio approach for 5 group variables: gender, age, living arrangement, use of hearing aids, and degree of hearing impairment. We investigated the magnitude of DIF by calculating the maximum difference between expected item scores for subgroups of the group variables of items showing DIF.

RESULTS

In a cross-sectional study, 408 consecutive individuals with hearing impairment completed the Dutch CPHI scales. Twelve items were deleted because of misfit to GRMs, 14 items showed uniform DIF, and 2 showed nonuniform DIF. Five items showing DIF were deleted due to large magnitude of DIF. The short form of the Dutch CPHI scales contains 35 items.

CONCLUSIONS

DIF analyses showed that the short form was relatively free of DIF with respect to the 5 group variables. Hence, there is no need to make adjustments for the calculation of subgroup scores.

Bacterial chromosomes are most often circular DNA molecules. This can produce a topological problem; a genetic crossover from homologous recombination results in dimerization of the chromosome. A chromosome dimer is lethal unless resolved. A site-specific recombination system catalyses this dimer-resolution reaction at the chromosomal site dif. In Escherichia coli, two tyrosine-family recombinases, XerC and XerD, bind to dif and carry out two pairs of sequential strand exchange reactions. However, what makes the reaction unique among site-specific recombination reactions is that the first step, XerD-mediated strand exchange, relies on interaction with the very C-terminus of the FtsK DNA translocase. FtsK is a powerful molecular motor that functions in cell division, co-ordinating division with clearing chromosomal DNA from the site of septation and also acts to position the dif sites for recombination. This is a model system for unlinking, separating and segregating large DNA molecules. Here we describe the molecular detail of the interaction between XerD and FtsK that leads to activation of recombination as deduced from a co-crystal structure, biochemical and in vivo experiments. FtsKγ interacts with the C-terminal domain of XerD, above a cleft where XerC is thought to bind. We present a model for activation of recombination based on structural data.

Chromosome dimers, which form during the bacterial life cycle, represent a problem that must be solved by the bacterial cell machinery so that chromosome segregation can occur effectively. The Xer/dif site-specific recombination system, utilized by most bacteria, resolves chromosome dimers into monomers using two tyrosine recombinases, XerC and XerD, to perform the recombination reaction at the dif site which consists of 28-30 bp. However, single Xer recombinase systems have been recently discovered in several bacterial species. In Streptococci and Lactococci a single recombinase, XerS, is capable of completing the monomerisation reaction by acting at an atypical dif site called dif SL (31 bp). It was recently shown that a subgroup of ε-proteobacteria including Campylobacter spp. and Helicobacter spp. had a phylogenetically distinct Xer/dif recombination system with only one recombinase (XerH) and an atypical dif motif (difH). In order to biochemically characterize this system in greater detail, Campylobacter jejuni XerH was purified and its DNA-binding activity was characterized. The protein showed specific binding to the complete difH site and to both halves separately. It was also shown to form covalent complexes with difH suicide substrates. In addition, XerH was able to catalyse recombination between two difH sites located on a plasmid in Escherichia coli in vivo. This indicates that this XerH protein performs a similar function as the related XerS protein, but shows significantly different binding characteristics.

BACKGROUND

Leukocytoclastic vasculitis is a well-known clinico-pathologic entity. A good correlation between clinical and direct immunofluorescence (DIF) findings has been shown only in the early stages of vasculitis. Our purpose was to determine the correlation between different stages of vasculitis, etiology of vasculitis, and DIF findings.

METHODS

Histologic and DIF studies were performed and evaluated from 40 patients with leukocytoclastic vasculitis.

RESULTS

Thirty-seven out of 40 patients (92%) showed positive DIF findings in the blood vessel walls. Eight patients were in the early stage of vasculitis and exhibited deposits mainly of fibrinogen, C3, and IgM. Seventeen patients were at the fully developed vasculitis stage and showed albumin, fibrinogen, and IgG deposits. Fifteen patients were in the late stage of vasculitis and showed deposits of mainly fibrinogen and C3 in the blood vessel walls.

CONCLUSIONS

The present study demonstrates that DIF examination is a very sensitive test in the diagnosis of vasculitis, and can be used in all stages of vasculitis and not only in the early stages as has been shown in previous studies.

BACKGROUND

Accurate estimation of burn size is of critical importance, as it is incorporated in every resuscitation formula. The aim of this study was to investigate total burn surface area (TBSA) accuracy among burn specialists, evaluate the potential impact of incorrect evaluation on variations of resultant fluid resuscitation volumes and to discuss future possibilities to estimate or measure TBSA more precisely.

METHODS

In a poll during two international burn meetings in 2010 and 2011 demonstrating three pictures of patients with different burn wound patterns and sizes we asked participants to estimate the total surface area burned in percentages. We then calculated resultant fluid volume differences based on established resuscitation formulas.

RESULTS

In the polled 80 participants, the estimations for three patients demonstrated the following differences (DIF=MAX-MIN): for patient 1, 2 and 3 they were 22.5 (25-2.5), 16.5 (20-3.5) and 31.5 (40-8.5) %TBSA, respectively. Based on these differences we calculated the volume differences for patients 1,2 and 3, which were 1080ml (Cincinnati Formula), 5280ml (Parkland Formula) and 2016ml (Cincinnati Formula), respectively.

CONCLUSIONS

The analysis showed high deviations of total body surface area among participants, also resulting in large variations of initial fluid resuscitation volumes. One option to address estimation variances is to perform more accurate assessments; also incorporating new technologies aiding to improve the quality of body surface estimations and related decisions.