Dysbiosis in the oral microbiomes of anti-CCP positive individuals at risk of developing rheumatoid arthritis

OBJECTIVES

An increased prevalence of periodontitis and perturbation of the oral microbiome has been identified in patients with rheumatoid arthritis (RA). The periodontal pathogen Porphyromonas gingivalis may cause local citrullination of proteins, potentially triggering anti-citrullinated protein antibody production. However, it is not known if oral dysbiosis precedes the onset of clinical arthritis. This study comprehensively characterised the oral microbiome in anti-cyclic citrullinated peptide (anti-CCP) positive at-risk individuals without clinical synovitis (CCP+at risk).

METHODS

Subgingival plaque was collected from periodontally healthy and diseased sites in 48 CCP+at risk, 26 early RA and 32 asymptomatic healthy control (HC) individuals. DNA libraries were sequenced on the Illumina HiSeq 3000 platform. Taxonomic profile and functional capability of the subgingival microbiome were compared between groups.

RESULTS

At periodontally healthy sites, CCP+at risk individuals had significantly lower microbial richness compared with HC and early RA groups (p=0.004 and 0.021). Microbial community alterations were found at phylum, genus and species levels. A large proportion of the community differed significantly in membership (523 species; 35.6%) and structure (575 species; 39.1%) comparing CCP+at risk and HC groups. Certain core species, including P. gingivalis, had higher relative abundance in the CCP+at risk group. Seventeen clusters of orthologous gene functional units were significantly over-represented in the CCP+at risk group compared with HC (adjusted p value <0.05).

CONCLUSION

Anti-CCP positive at-risk individuals have dysbiotic subgingival microbiomes and increased abundance of P. gingivalis compared with controls. This supports the hypothesis that the oral microbiome and specifically P. gingivalis are important in RA initiation.

SAT0045 DISTRIBUTION AND SEVERITY OF PERIODONTITIS PREDICTS PROGRESSION TO INFLAMMATORY ARTHRITIS IN ANTI-CCP POSITIVE AT-RISK INDIVIDUALS WITHOUT CLINICAL SYNOVITIS

Background:

The prevalence of periodontal disease and the citrullinating bacteriumPorphyromonas gingivalisare increased in anti-CCP positive individuals at-risk of rheumatoid arthritis (RA) (1). This suggests periodontal inflammation may have an important role in the initiation and development of RA. Despite significant interest in the role of the periodontium and other mucosal sites in the initiation of RA-related autoimmunity, the influence of mucosal inflammation on progression to inflammatory arthritis (IA) in at-risk individuals remains unclear.

Objectives:

To investigate the association between periodontitis and progression to inflammatory arthritis in anti-CCP+ at-risk individuals without synovitis.

Methods:

Anti-CCP positive individuals with musculoskeletal symptoms but no clinical synovitis (CCP+ at-risk) were recruited as part of a national prospective cohort study. Comprehensive periodontal examination was performed at baseline by a dentist; six sites per tooth were assessed for clinical attachment level (CAL), pocket depth (PD) and bleeding on probing (BOP). Periodontal disease sites (PDD) were defined as CAL ≥2mm and PD ≥4mm. The distribution of PDD was classified in line with recent guidelines (2). The severity i.e. total burden of periodontal inflammation, was quantified at patient level using the periodontal inflamed surface area (PISA) index(3). CCP+ at-risk were monitored for progression to IA. Multivariable Cox regression was used to assess the effect of PDD distribution and PISA on progression to IA.

Results:

126 CCP+ at-risk underwent full periodontal examination and were followed up for median 23.4 months (range 0.6 – 56.8 months). Mean age was 49 years, 86 (68%) were females. At baseline, 42(33%) subjects had no PDD, 51(40%) had localised PDD (<30% teeth with one or more PDD site) and 33 (26%) had generalised PDD (≥ 30% of teeth with one or more PDD site). Mean (SD) PISA for all subjects was 267(319)mm2. 31 subjects (25%) progressed to IA after median of 12.6 months (range 0.6 – 49.5 months). Progression to IA was significantly higher in subjects with localised PDD compared with those without PDD (33% vs 16%, HR (95% CI) 2.45 (1.02, 5.94) p=0.02), figure 1. Interestingly, this association was not seen in subjects with generalised PDD (19% progression, HR 0.68 (0.20, 2.32). In addition, severity (i.e. total burden) of periodontal inflammation (PISA) was not significantly predictive of progression to IA alone (HR 1.001 (0.999-1.002), p=0.08). However, when adjusting for distribution of PDD, PISA was significantly associated with progression to IA (HR 1.0016 (1.0003- 1.003), p=0.00163).

Conclusion:

Periodontal inflammation predicts progression to IA in CCP+ at-risk individuals without clinical synovitis. The severity (i.e. total burden) of periodontitis appears to be particularly predictive of progression to IA in patients with localised periodontitis. These data suggest periodontitis may be an important factor in the development of RA and provide rationale for periodontal intervention with the aim of arthritis prevention in at-risk individuals.

References:

[1] Mankia K et al, JAMA Network Open(2019)

[2] Caton J et al, J Clin Periodontol(2018)

[3] Nesse W et al, J Clin Periodontol(2008)

Disclosure of Interests :

Kulveer Mankia: None declared, Zhain Mustufvi: None declared, Jing Kang: None declared, Aradhna Tugnait: None declared, Robert Letton: None declared, Laurence Duquenne: None declared, Alastair Speirs: None declared, Val Clerehugh: None declared, Deirdre Devine: None declared, Paul Emery Grant/research support from: AbbVie, Bristol-Myers Squibb, Merck Sharp & Dohme, Pfizer, Roche (all paid to employer), Consultant of: AbbVie (consultant, clinical trials, advisor), Bristol-Myers Squibb (consultant, clinical trials, advisor), Lilly (clinical trials, advisor), Merck Sharp & Dohme (consultant, clinical trials, advisor), Novartis (consultant, clinical trials, advisor), Pfizer (consultant, clinical trials, advisor), Roche (consultant, clinical trials, advisor), Samsung (clinical trials, advisor), Sandoz (clinical trials, advisor), UCB (consultant, clinical trials, advisor)

Functional genomic landscape of acute myeloid leukaemia

The implementation of targeted therapies for acute myeloid leukaemia (AML) has been challenging because of the complex mutational patterns within and across patients as well as a dearth of pharmacologic agents for most mutational events. Here we report initial findings from the Beat AML programme on a cohort of 672 tumour specimens collected from 562 patients. We assessed these specimens using whole-exome sequencing, RNA sequencing and analyses of ex vivo drug sensitivity. Our data reveal mutational events that have not previously been detected in AML. We show that the response to drugs is associated with mutational status, including instances of drug sensitivity that are specific to combinatorial mutational events. Integration with RNA sequencing also revealed gene expression signatures, which predict a role for specific gene networks in the drug response. Collectively, we have generated a dataset-accessible through the Beat AML data viewer (Vizome)-that can be leveraged to address clinical, genomic, transcriptomic and functional analyses of the biology of AML.

Hyaluronan-Based Nanohydrogels for Targeting Intracellular S. Aureus in Human Keratinocytes

Staphylococcus aureus is one of the most significant human pathogens that is frequently isolated in a wide range of superficial and systemic infections. The ability of S. aureus to invade and survive within host cells such as keratinocytes and host immune cells has been increasingly recognized as a potential factor in persistent infections and treatment failures. The incorporation of antibiotics into hyaluronan-cholesterol nanohydrogels represents a novel paradigm in the delivery of therapeutic agents against intracellular bacteria. The work presented herein shows that NHs quickly enter human keratinocytes and accumulate into lysosomes. When used for targeting intracellular S. aureus the antimicrobial activity of loaded levofloxacin is enhanced, possibly changing the antibiotic intracellular fate from cytosol to lysosome. Indeed, gentamicin, an antibiotic that predominantly accumulates in lysosomes, shows significant and equal antibacterial activity when entrapped into NHs. These results strongly suggest that lysosomal formulations may display preferential activity toward intracellular S. aureus, opening new avenues for the use of HA-based NHs for treatment of such skin infections.

The metatranscriptomes of root caries and sound root surface biofilms

There is limited knowledge of bacterial metabolism in root caries lesions. The aim of this study was to describe the bacterial metatranscriptomes associated with root caries and sound root surfaces using an RNA-seq analysis approach.

The biofilms from exposed root surfaces were sampled from caries-free volunteers (n=10), and from the infected dentine of volunteers with root caries (n=30). Total bacterial RNA was extracted; cDNA libraries were prepared and sequenced on the Illumina Hi-Seq2500. The function and composition of the metabolically active microbiota were investigated using: a) MG-RAST, and b) denovo assembly of the read data and mapping to contigs. Differential gene expression analysis was done using the R package DESeq2 (padj <10⁻³).

Transcripts with the highest expression levels were those coding for membrane transport systems, ribosomal proteins, enolase and glycolytic pathways in both groups. Differential analysis indicated that genes coding for the OmpA domain protein and metalloprotease domain protein were over-expressed in the caries samples (log₂FoldChange = –12.2; padj= 3.5 × 10⁻¹³), whereas genes in the samples from healthy sites over-expressed pilus biosynthesis protein, thiamine diphosphokinase and transporter protein (log₂FoldChange = 16.5; padj = 2.2 × 10⁻²¹).

Metatranscriptomic analyses show unique gene expression profiles in sound root surface and carious biofilms.

The subgingival microbiomes in periodontitis and health of individuals with rheumatoid arthritis and at risk of developing rheumatoid arthritis

Serum anti-citrullinated protein antibodies (ACPAs), present in 70% of people with rheumatoid arthritis (RA), can be detected ≤10years before the onset of clinical disease. RA and periodontitis are epidemiologically associated and we have reported a high incidence of periodontitis in people who are ACPA+ and at risk of RA. Periodontal bacteria may contribute by multiple routes to the generation of RA-autoantibodies. This study aims to characterise the subgingival microbiomes from periodontitis and health in individuals with/without RA and at risk of RA.

Forty-five ACPA+ no RA (RA-at-risk; RAR), 31 healthy controls (HC) and 30 ACPA+ RA patients (RA) underwent a periodontal examination. DNA from subgingival plaque from healthy and deep pocket sites were paired-end sequenced using the Illumina HiSeq3000 and data analysed using MG-RAST + DESeq.

Metagenomes in RA samples had high proportions of Actinobacteria; RAR microbiomes contained higher proportions of Bacteroidetes than HC. The relative abundance of P. gingivalis was high in periodontitis and RAR; Aggregatibacter actinomycetemcomitans was detected with similar frequency in each group. Other bacteria implicated in periodontitis and/or autoantibody generation (Filifactor alocis, Prevotella spp, Leptotrichia spp.) were detected. Analyses are on-going to elucidate the diversity and functional potential of the subgingival microbiome associated with RA.

Dental Pulp Cells Isolated from Teeth with Superficial Caries Retain an Inflammatory Phenotype and Display an Enhanced Matrix Mineralization Potential

We have isolated dental pulp cells (DPCs) from three healthy (hDPCs) and three carious (cDPCs) donors and shown that compared to hDPCs cells isolated from superficial carious lesions show higher clonogenic potential; show an equivalent proportion of cells with putative stem cell surface markers; show enhanced matrix mineralization capability; have enhanced angiogenic marker expression and retain the inflammatory phenotype in vitro characteristic of superficial caries lesions in vivo. Our findings suggest that cDPCs may be used for further investigation of the cross talk between inflammatory, angiogenic and mineralization pathways in repair of carious pulp. In addition cells derived from carious pulps (almost always discarded) may have potential for future applications in mineralized tissue repair and regeneration.

IGFBP-2 and -3 co-ordinately regulate IGF1 induced matrix mineralisation of differentiating human dental pulp cells

Human dental pulp cells (DPCs), which are known to contain a subset of stem cells capable of reforming a dentin and pulp-like complex upon in vivo transplantation, were isolated from third molars of three healthy donors and differentiated to a matrix mineralisation phenotype using by culture in dexamethasone and l-ascorbic acid. qRT-PCR analysis of insulin-like growth factor ( IGF) axis gene expression indicated that all genes, except insulin-like growth factor 1 (IGF1) and insulin-like growth factor binding protein-1 ( IGFBP-1), were expressed in DPCs. During differentiation upregulation of insulin-like growth factor binding protein-2 (IGFBP-2) and downregulation of insulin-like growth factor binding protein-3 (IGFBP-3) expression was observed. Changes in IGFBP-2 and IGFBP-3 mRNA expression were confirmed at the protein level by ELISA of DPC conditioned medium functional analysis indicated that IGF1 stimulated the differentiation of DPCs and that the activity of the growth factor was enhanced by pre-complexation with IGFBP-2 but inhibited by pre-complexation with IGFBP-3. Therefore changes in IGFBP-2 and -3 expression during differentiation form part of a co-ordinated functional response to enhance the pro-differentiative action of IGF1 and represent a novel mechanism for the regulation of DPC differentiation.

Actinomyces spp. gene expression in root caries lesions

Background

The studies of the distribution of Actinomyces spp. on carious and non-carious root surfaces have not been able to confirm the association of these bacteria with root caries, although they were extensively implicated as a prime suspect in root caries.

Objective

The aim of this study was to observe the gene expression of Actinomyces spp. in the microbiota of root surfaces with and without caries.

Design

The oral biofilms from exposed sound root surface (SRS; n=10) and active root caries (RC; n=30) samples were collected. The total bacterial RNA was extracted, and the mRNA was isolated. Samples with low RNA concentration were pooled, yielding a final sample size of SRS=10 and RC=9. Complementary DNA (cDNA) libraries were prepared and sequenced on an Illumina^® HiSeq 2500 system. Sequence reads were mapped to eight Actinomyces genomes. Count data were normalized using DESeq2 to analyse differential gene expression applying the Benjamini-Hochberg correction (false discovery rate [FDR]<0.001).

Results

Actinomyces spp. had similar numbers of reads (Mann-Whitney U-test; p>0.05), except for Actinomyces OT178 (p=0.001) and Actinomyces gerencseriae (p=0.004), which had higher read counts in the SRS. Genes that code for stress proteins (clp, dnaK, and groEL), enzymes of glycolysis pathways (including enolase and phosphoenolpyruvate carboxykinase), adhesion (Type-2 fimbrial and collagen-binding protein), and cell growth (EF-Tu) were highly – but not differentially (p>0.001) – expressed in both groups. Genes with the most significant upregulation in RC were those coding for hypothetical proteins and uracil DNA glycosylase (p=2.61E-17). The gene with the most significant upregulation in SRS was a peptide ABC transporter substrate-binding protein (log2FC=−6.00, FDR=2.37E-05).

Conclusion

There were similar levels of Actinomyces gene expression in both sound and carious root biofilms. These bacteria can be commensal in root surface sites but may be cariogenic due to survival mechanisms that allow them to exist in acid environments and to metabolize sugars, saving energy.

T Cell Costimulation by Derivatives of Benzoic Acid

A number of analogues of benzoic acid were evaluated in a T cell costimulation assay. One compound, the sodium salt of 2-chloro-5-nitrobenzoic acid (CNBA-Na) was chosen for further study and was found to be a potent costimulator of anti-CD3-induced proliferation of both H9 lymphoblastoid cells ( P<0.001) and human peripheral blood mononuclear cells ( P=0.001) in a dose-dependent manner. The costimulatory effect of CNBA-Na on CD3-triggered DNA synthesis did not enhance human immunodeficiency virus replication in infected cells. Studies with blocking monoclonal antibodies against B7-1 or B7-2 indicated that the immunopotentiatory effect of CNBA-Na required a macromolecular interaction between CD28 (a costimulatory receptor on T cells) and its counter receptor B7 expressed on antigen-presenting cells. The discovery that this low molecular weight compound causes T cell proliferation highlights a potentially novel therapeutic approach to immunodeficiency diseases.

Counting platelets at transfusion threshold levels: impact on the decision to transfuse. A BEST Collaborative - UK NEQAS(H) International Exercise

BACKGROUND AND OBJECTIVES

Obtaining accurate and precise platelet enumeration in automatic platelet analysers at low platelet counts is a challenge. To explore the performance of current haematology analysers in counting platelet concentrations usually used as platelet transfusion threshold.

MATERIAL AND METHODS

An international exercise where four blood samples with platelet levels near usual platelet transfusion thresholds was prepared and distributed.

RESULTS

The samples shipped had a platelet count of 6·3, 13·3, 21·6 and 53·0 × 10(9) /l according to the international reference method. We received 82 sets of results from nine countries. Instruments from six different manufacturers were represented. Although the mean count for each of the four samples was very similar to the values, according to the reference method (9·0, 16·2, 23·0 and 57·6 × 10(9) /l), significant variability in the results was found. Assuming that these were patient samples and the result of the count used to indicate a prophylactic platelet transfusion, undertransfusion would have occurred for 24·5% of the LP1 samples at a transfusion threshold of 10 × 10(9) /l and, at a threshold of 20 × 10(9) /l, undertransfusion would have occurred for 7·2% of the LP1 and 16·2% of the LP2 samples and overtransfusion would have occurred with 23·1% of the LP3 samples.

CONCLUSION

The results suggest that significant inaccuracy exists in counting low levels of platelets and that this inaccuracy might have a significant impact in under- and overtransfusion of platelet concentrates to patients.

Oral biofilms: molecular analysis, challenges, and future prospects in dental diagnostics

Oral biofilms are functionally and structurally organized polymicrobial communities that are embedded in an extracellular matrix of exopolymers on mucosal and dental surfaces. These biofilms are found naturally in health, and provide benefits to the host. However, this relationship can break down, and disease can occur; disease is associated with a shift in the balance of the species within these biofilms. Simple diagnostic tests have been developed that involve the culture of selected bacteria, eg, those implicated in dental caries, facilitating an assessment of risk of further disease in individual patients. However, oral diseases have a complex etiology, and because only around 50% of oral biofilm can be grown at present, culture-independent molecular-based approaches are being developed that give a more comprehensive assessment of the presence of a range of putative pathogens in samples. The diversity of these biofilms creates challenges in the interpretation of findings, and future work is investigating the ability of novel techniques to detect biological activity and function in oral biofilms, rather than simply providing a catalogue of microbial names.

Establishment of the first international repository for transfusion-relevant bacteria reference strains: ISBT working party transfusion-transmitted infectious diseases (WP-TTID), subgroup on bacteria

BACKGROUND

Bacterial contamination of platelet concentrates (PCs) still remains a significant problem in transfusion with potential important clinical consequences, including death. The International Society of Blood Transfusion Working Party on Transfusion-Transmitted Infectious Diseases, Subgroup on Bacteria, organised an international study on Transfusion-Relevant Bacteria References to be used as a tool for development, validation and comparison of both bacterial screening and pathogen reduction methods.

MATERIAL AND METHODS

Four Bacteria References (Staphylococcus epidermidis PEI-B-06, Streptococcus pyogenes PEI-B-20, Klebsiella pneumoniae PEI-B-08 and Escherichia coli PEI-B-19) were selected regarding their ability to proliferate to high counts in PCs and distributed anonymised to 14 laboratories in 10 countries for identification, enumeration and bacterial proliferation in PCs after low spiking (0·3 and 0·03 CFU/ml), to simulate contamination occurring during blood donation.

RESULTS

Bacteria References were correctly identified in 98% of all 52 identifications. S. pyogenes and E. coli grew in PCs in 11 out of 12 laboratories, and K. pneumoniae and S. epidermidis replicated in all participating laboratories. The results of bacterial counts were very consistent between laboratories: the 95% confidence intervals were for S. epidermidis: 1·19-1·32 × 10(7) CFU/ml, S. pyogenes: 0·58-0·69 × 10(7) CFU/ml, K. pneumoniae: 18·71-20·26 × 10(7) CFU/ml and E. coli: 1·78-2·10 × 10(7) CFU/ml.

CONCLUSION

The study was undertaken as a proof of principle with the aim to demonstrate (i) the quality, stability and suitability of the bacterial strains for low-titre spiking of blood components, (ii) the property of donor-independent proliferation in PCs, and (iii) their suitability for worldwide shipping of deep frozen, blinded pathogenic bacteria. These aims were successfully fulfilled. The WHO Expert Committee Biological Standardisation has approved the adoption of these four bacteria strains as the first Repository for Transfusion-Relevant Bacteria Reference Strains and, additionally, endorsed as a project the addition of six further bacteria strain preparations suitable for control of platelet contamination as the next step of enlargement of the repository.

Evaluation of noninvasive methods for the estimation of haemoglobin content in red blood cell concentrates

OBJECTIVES

Red blood cell concentrates (RCCs) are the major blood component transfused to patients. There is a great variability in patient response, depending on both the patient's blood volume and haemoglobin content in the RCC. Standardisation of transfusion practice is needed to improve the prediction of patient outcome.

AIM

We hypothesise that labelling of RCCs with haemoglobin content will add possibilities for the standardisation of transfusion practice.

METHODS

Data from multiple international transfusion services regarding haemoglobin content and weight or volume of RCC were collected and analysed.

RESULTS

We demonstrate a strong and highly significant correlation between haemoglobin content with both weight and volume of the RCCs. A linear regression model was used to assess these relationships, and it demonstrates how haemoglobin content can be estimated for different cell production processes.

CONCLUSIONS

We recommend the use of weight or volume of the RCCs as the basis of estimating haemoglobin in the RCC and postulate that this can be used in future studies to explore the effects of a haemoglobin dose-based transfusion system. As the weight - and sometimes the volume - of the blood bag is easily accessible, in contrast to direct haemoglobin measurements from each individual unit, this method is feasible and simple.

Long-term effects of pre-surgical stress management for men with early stage prostate cancer undergoing radical prostatectomy (RP)

5148

Background: We conducted a randomized trial to examine pre-surgical stress management for men undergoing RP. We previously reported on the short-term benefits in reducing mood disturbances before and after surgery. Methods: One hundred and fifty- eight men were randomly assigned to one of three conditions. Men in the stress management (SM) group discussed their fears and concerns about the upcoming surgery and were taught diaphragmatic breathing, guided imagery, an imaginal exposure to the day of surgery, and exposure to adaptive coping skills. Men in the supportive attention (SA) group discussed their fears and concerns about the upcoming surgery and then a semi-structured interview was conducted. Men in the SM and SA groups met with a clinical psychologist two times prior to surgery, a brief session just prior to surgery, and then again prior to discharge. Men in the usual care (UC) group had no meetings with a psychologist. Men completed psychosocial and quality of life (QOL) measures including distress (BSI-GSI), intrusive thoughts (IES), and QOL (SF-36), at baseline and 6 and 12 months later. Results: Men were primarily Caucasian (78%), married (85%) and highly educated (80% some college or higher). Mixed model analyses, controlling for ethnicity, age, martial status, stage, baseline PSA, Gleason score, and the respective baseline measure, indicated a significant group main effect for SF-36 Role Physical (SF-RP)(p=0.01). Post-hoc analyses revealed significantly higher SF-RP scores for the SM (86) vs. UC (63) group and marginally higher scores for the SM (86) vs. SA (73) group. There was a marginally significant group main effect for pain scores (SF-BP) (p=0.12) with the SM group reporting significantly better pain scores than the UC group (80 vs. 71), and neither group differed from the SA group (77). There was also a group by time effect for general health scores (SF-GH) revealing by 12 months after surgery that the SM (74) and SA (76) groups both reported higher SF-GH scores than the UC group (68). There were no group differences on any of the other outcomes. Conclusions: Results suggest that even a brief pre-surgical stress management intervention is beneficial in terms of improving aspects of QOL 6 and 12 months after RP. Funding: NIMH/NCI RO1MH59432

No significant financial relationships to disclose.

Enhancement of erythrosine-mediated photodynamic therapy of Streptococcus mutans biofilms by light fractionation

OBJECTIVES

We aimed to increase the bacterial cell killing efficacy of erythrosine-mediated photodynamic therapy (PDT) of Streptococcus mutans biofilms by fractionating the delivered light dose into a series of shorter pulses.

METHODS

S. mutans biofilms of 200 microm thickness were grown in a constant-depth film fermenter (CDFF). Biofilms were incubated with 22 microM erythrosine before being irradiated with white light for increasing periods of time. We also used light dose fractionation to deliver the same overall dose of light in a series of shorter pulses separated by dark periods. Bacterial cell killing as a result of each killing protocol was quantified by colony counting.

RESULTS

A 2 log10 of bacterial cell killing was achieved with 5 min of continuous white light irradiation. For time periods longer than 5 min the amount of killing increased more slowly, which was probably due to photobleaching of the erythrosine. Fractionation of the light dose into 5 x 1 min doses separated by dark recovery periods of 5 min increased the amount of bacterial killing by 1 log10 compared with 5 min continuous irradiation. Further fractionation of the light dose into 10x 30 s doses separated by 2 min recovery periods resulted in 3.7 log10 of cell kill, an improvement of 1.7 log10 compared with the continuous irradiation protocol.

CONCLUSIONS

Erythrosine-mediated PDT of S. mutans biofilms can be further enhanced by fractionation of the applied light dose.

Erythrosine is a potential photosensitizer for the photodynamic therapy of oral plaque biofilms

OBJECTIVES

The purpose of this study was to evaluate the clinical plaque disclosing agent erythrosine as a photosensitizer in the photodynamic killing of the oral bacterium Streptococcus mutans grown as a biofilm.

METHODS

S. mutans biofilms of 200 microm thickness were grown in a constant-depth film fermenter. In addition to determining localization of the photosensitizer within biofilms using confocal laser scanning microscopy (CLSM), we compared the bacterial killing efficacy of erythrosine with that of two well-characterized photosensitizers, methylene blue (MB) and photofrin. Incubations were carried out with each photosensitizer (22 microM), and irradiation was for 15 min using a 400 W white light source.

RESULTS

The CLSM results showed that erythrosine is taken up into S. mutans biofilms, where it is associated with the biomass of the biofilm rather than the fluid-filled channels and voids. Comparison of the cell killing efficacy of erythrosine in S. mutans biofilms of different ages showed that erythrosine was 1-2 log(10) more effective at killing biofilm bacteria than photofrin and 0.5-1 log(10) more effective than MB. The results were statistically significant (P < 0.01). Photodynamic therapy (PDT) with all three photosensitizers was increasingly effective as biofilm age increased, suggesting that temporal changes in biofilm architecture and composition affect susceptibility to PDT.

CONCLUSIONS

PDT using erythrosine as photosensitizer shows excellent potential as a treatment for oral plaque biofilms.

Chlorhexidine-modified glass ionomer for band cementation? An in vitro study

OBJECTIVE

To compare the mean retentive strength, predominant site of band failure, amount of cement remaining on the tooth at deband and survival time of orthodontic micro-etched bands cemented with chlorhexidine-modified (CHXGIC) or conventional glass ionomer cement (GIC).

DESIGN

In vitro study.

SETTING

Dental Materials Laboratory.

MATERIALS AND METHODS

One-hundred-and-twenty intact, caries-free third molars were collected from patients attending for third molar surgery. These were stored for 3 months in distilled water and decontaminated in 0.5% chloramine. To assess retentive strength, 80 teeth were randomly selected and 40 were banded with each cement. Testing was undertaken using a Nene M3000 testing machine at a cross-head speed of 1 mm/min. Following debanding, the predominant site of failure was recorded as cement-enamel or cement-band interface. The amount of cement remaining on the tooth surface following deband was assessed and coded. Survival time for another 40 banded specimens, 20 cemented with each cement, was assessed following application of mechanical stress in a ball mill.

MAIN OUTCOME MEASURES

Retentive strength, predominant site of failure, amount of cement remaining on the tooth surface, survival time.

RESULTS

Mean retentive strength for bands cemented with CHXGIC (0.32 MPa, SD 0.09) or GIC (0.28 MPa, SD 0.07) did not differ significantly (p=0.05). All bands failed at the enamel-cement interface. There was no significant difference in the amount of cement remaining on the tooth surface after deband for each cement type (p=0.23). The mean survival time of bands cemented with CHXGIC or GIC was 7.0 and 6.4 hours, respectively (p=0.23).

CONCLUSIONS

There was no significant difference in mean retentive strength, amount of cement remaining on the tooth after deband or mean survival time of bands cemented with CHXGIC or GIC. Bands cemented with either cement failed predominantly at the enamel-cement interface. The results suggest that CHXGIC may have comparable clinical performance to GIC for band cementation.

Evidence Report on the Occurrence, Assessment, and Treatment of Fatigue in Cancer Patients

To determine the occurrence of cancer-related fatigue, the methods used to assess it, and the efficacy of the available treatments, we performed literature searches that identified English-language publications on these topics. Twenty-seven studies were identified in which the quantitative estimation of the occurrence of cancer-related fatigue was an end point. Fifty-six were judged to be relevant to the assessment of fatigue, and 10 randomized controlled clinical trials of treatments of cancer-related fatigue were retrieved. The occurrence of cancer-related fatigue was found to range from 4% to 91%, depending on the population studied and the methods of assessment. Few population-based studies and no longitudinal studies of cancer-related fatigue have been performed. The methods of fatigue assessment were highly variable. Exercise programs show promise to prevent or treat fatigue in some subsets of cancer patients, and the use of epoetin alfa for correction of anemia has been shown to ameliorate fatigue. The number of subjects in the treatment trials was small and their methodologic quality was inconsistent.

Developing explanatory models of health inequalities in childhood dental caries

OBJECTIVE

Long-term aim is to determine optimum interventions to reduce dental caries in children in disadvantaged communities and minimise the effects of exclusion from health care systems, of ethnic diversity, and health inequalities.

DESIGN

Generation of initial explanatory models, study protocol and development of two standardised measures. First, to investigate how parental attitudes may impact on their children's oral health-related behaviours and second, to assess how dentists' attitudes may impact on the provision of dental care.

SUBJECTS

Core research team, lead methodologists, 44 consortium members from 18 countries. To complete the development of the questionnaire, the initial set of items was administered to parents (n = 23) with children in nursery schools in Dundee, Scotland and sent to the same parents one week later. A standardised measure examining barriers to providing dental care for children aged 3 to 6 years was developed. 20 dentists working in primary dental care in Scotland completed the measure on two different occasions separated by one week.

RESULTS

Explanatory models were developed. Family questionnaire: test-retest reliability excellent (r = 0.93 p < or = 0.001) with very good internal reliability (alpha = 0.89). Dentists questionnaire: excellent test-re-test reliability r = 0.88, (alpha = 0.90).

CONCLUSIONS

Interaction between consortium members enhanced the validity of the questionnaires and protocols for different cultural locations. There were challenges in developing and delivering this multi-centre study. Experience gained will support the development of substantive trials and longitudinal studies to address the considerable international health disparity of childhood dental caries.

Endocrine levels at the start of treatment are associated with subsequent psychological adjustment in cancer patients with metastatic disease

OBJECTIVE

This study examined the association between hormonal profiles at the start of cancer treatment and subsequent psychological symptomatology.

METHODS

Twenty-seven patients with metastatic renal cell carcinoma and 18 patients with metastatic melanoma completed three assessments during the course of treatment: at the start of treatment (baseline), at the end of treatment (3 weeks after baseline), and at a follow-up appointment 1 month later. Cortisol, norepinephrine, and epinephrine levels were measured at baseline using 15-hour urine samples. At each assessment, patients completed the Impact of Event Scale (IES) and the Brief Symptom Inventory (BSI).

RESULTS

Patients reported moderate levels of distress throughout treatment as measured by the IES and BSI. Norepinephrine levels at the start of treatment were positively associated with IES total scores at the end of treatment and at follow-up, and cortisol levels were positively associated with IES total scores at follow-up after adjusting for baseline IES and overall distress scores. Norepinephrine levels were also positively associated with depression scores at follow-up, and cortisol levels were positively associated with depression scores at the end of treatment and at follow-up after adjusting for baseline depression and overall distress scores.

CONCLUSIONS

Hormonal profiles at the start of cancer treatment are associated with subsequent psychological adjustment.

Investigation to evaluate and validate the Leeds in situ device for the study of enamel remineralisation in vivo

OBJECTIVES

Recently, a novel device to generate dental plaque in situ on a removable human enamel surface was described. The device permitted the recovery of plaque intact and undisturbed on its enamel substrate. The aim of this investigation was to determine the utility and robustness of this model for analysis of the effects of therapeutics on both enamel remineralisation and on the overlying biofilm composition.

METHODS

Enamel slices were taken from extracted sound human teeth, sterilised and a 'flat' area ground on each slice. An artificial lesion was formed within this area using acidified gel and the hardness of the enamel within the area of the lesion was determined at five sites using a 'Vickers' indenter. A nylon ring was then attached over the area of the lesion with cyanoacrylate and the excess enamel removed to form the completed device. Two devices were attached to the upper molars of 22 volunteers. Each volunteer was randomly assigned to receive either a fluoride containing (1500 ppm) or a fluoride free dentifrice. The devices were retained for a 4 week period whilst undertaking normal oral hygiene. All procedures were conducted according to GCP. After a 2 week break, the volunteers were fitted with two further devices, given dentifrice of the alternate type and the procedure repeated. Plaque from each device was harvested for microbiological analyses and the enamel subject to microhardness measurement. Then for each device the change in microhardness of the enamel within the lesion over the 4 week period was calculated.

RESULTS

There were no significant differences in viable counts of total aerobic bacteria, mutans streptococci or lactobacilli, nor in acidic, aciduric or arginolytic populations in plaque from patients using the two different dentifrices. However, devices subjected to the fluoride containing dentifrice demonstrated a significantly greater increase in microhardness of the enamel (P<0.025).

CONCLUSIONS

These results suggest that the novel in situ device is capable of measuring the effect of 1500 ppm fluoride on remineralisation of carious enamel over a 4 week period and is also well suited to determining concomitant effects on plaque ecology.

Risk-resistance adaptation model for caregivers and their children with sickle cell syndromes

This investigation examined the risk-resistance adaptation model for children with sickle cell disease and their primary caregivers. Participants were 55 children, ranging in age from 5 to 16 years with a mean age of 9 years 2 months, diagnosed with sickle cell disease and their primary caregivers, recruited from a university medical center. Measures included adjustment (i.e. primary caregiver and child adjustment), risk factors (i.e. disease and disability, functional independence, and psychosocial stressors), resistance factors (i.e. intrapersonal health locus of control, social-ecological), and stress processing (coping). Primary caregivers' adjustment was associated with developmental coping, changeR2 = .08, and child adaptation was associated with an internal health locus of control, changeR2 = .22. An indirect effect of primary caregivers' coping on child adjustment was found through influence on primary caregivers' adjustment, changeR2 = .11. The findings support research among other chronically ill populations that suggests an association between coping and disease adjustment. The results were interpreted to support the use of theoretically driven models in predicting the adaptation of children with chronic illness and adjustment in their caregivers.

The AtCAO gene, encoding chlorophyll a oxygenase, is required for chlorophyll b synthesis in Arabidopsis thaliana

Chlorophyll b is synthesized from chlorophyll a and is found in the light-harvesting complexes of prochlorophytes, green algae, and both nonvascular and vascular plants. We have used conserved motifs from the chlorophyll a oxygenase (CAO) gene from Chlamydomonas reinhardtii to isolate a homologue from Arabidopsis thaliana. This gene, AtCAO, is mutated in both leaky and null chlorina1 alleles, and DNA sequence changes cosegregate with the mutant phenotype. AtCAO mRNA levels are higher in three different mutants that have reduced levels of chlorophyll b, suggesting that plants that do not have sufficient chlorophyll b up-regulate AtCAO gene expression. Additionally, AtCAO mRNA levels decrease in plants that are grown under dim-light conditions. We have also found that the six major Lhcb proteins do not accumulate in the null ch1-3 allele.

Women who are HIV infected: the role of religious activity in psychosocial adjustment

The role of religious activity in the psychosocial adjustment of 205 inner-city African-American women, one-half of whom are HIV infected, was examined. Those who were HIV infected reported praying more but viewed prayer as less effective in coping with a chronic illness. Frequency of prayer predicted optimism about the future, whereas religious activity was not related to current depressive symptoms.

Purification and functional analysis of the DnaK homologue from Prevotella intermedia OMZ 326

This study examined heat shock proteins (hsps) of the periodontal pathogen Prevotella intermedia and the closely related species, Prevotella nigrescens and Prevotella corporis. After heat shock at 45 degrees C for 5 min, cell-free extracts were analysed by SDS-PAGE and Western blotting with polyclonal antibodies against Escherichia coli hsps. P. intermedia, P. nigrescens and P. corporis all expressed a DnaK homologue. The P. nigrescens DnaK was of a similar molecular mass to E. coli DnaK (70 kDa), whilst those of P. intermedia and P. corporis were approximately 69 kDa. DnaJ homologues were expressed in each species; however, no homologue of GrpE was detected. P. intermedia DnaK was purified to homogeneity by ion-exchange and affinity-chromatography, and was shown to restore activity of denatured luciferase. This molecular chaperone activity was enhanced by E. coli DnaJ and GrpE which are components of the Hsp70 molecular chaperone machine.

Prospective evaluation of neutrophil autoantibodies in 500 consecutive patients with inflammatory bowel disease

Previous studies have shown antineutrophil cytoplasmic autoantibodies (ANCA) in patients with inflammatory bowel disease (IBD). A particular subclass, the so-called 'atypical' (perinuclear) p-ANCA type, occurs in the majority of patients with ulcerative colitis. The purpose of this prospective study was to assess, in a blinded fashion, this 'subclinical' serological marker in a consecutive series of IBD patients. Five hundred patients were evaluated, including 247 patients with ulcerative colitis and 253 with Crohn's disease involving the small and/or large intestine. Overall, 194 (38.8%) of all patients with IBD were positive, including 164 (66.3%) with ulcerative colitis and 30 (11.9%) with Crohn's disease. Except for coexistent sclerosing cholangitis, no other clinical or laboratory variable had an effect on the rate of ANCA detection. This is the largest single study of ANCA in patients with IBD and the only study to provide data solely from a single Canadian centre. Results emphasize the immunopathological differences between ulcerative colitis and Crohn's disease, and indicate that both disorders are heterogeneous inflammatory disease processes.

Cascading toward divorce: the roles of marital and child factors

This longitudinal study examined the role of marital and child factors in predicting divorce potential and actual divorce occurrence. Participants included 140 young adolescents (73 girls, 67 boys; mean age = 13 years 2 months) and their parents. Child-related (number of children in the family, the presence of a male child in the family, and the adolescent's level of anxiety-withdrawal and conduct disorder problems) and intramarital (marital satisfaction and, for some analyses, divorce potential) factors served as predictors. For both wife and husband data, lower levels of marital satisfaction predicted higher current levels of divorce potential, and, in turn, divorce potential predicted greater likelihood for divorce up to 7 years later. No child-related variables predicted divorce potential or divorce occurrence.

Cascading toward divorce: the roles of marital and child factors

This longitudinal study examined the role of marital and child factors in predicting divorce potential and actual divorce occurrence. Participants included 140 young adolescents (73 girls, 67 boys; mean age = 13 years 2 months) and their parents. Child-related (number of children in the family, the presence of a male child in the family, and the adolescent's level of anxiety-withdrawal and conduct disorder problems) and intramarital (marital satisfaction and, for some analyses, divorce potential) factors served as predictors. For both wife and husband data, lower levels of marital satisfaction predicted higher current levels of divorce potential, and, in turn, divorce potential predicted greater likelihood for divorce up to 7 years later. No child-related variables predicted divorce potential or divorce occurrence.

Quartz inactivates alpha 1-antiproteinase: possible role in mineral dust-induced emphysema

Occupational exposure to some types of mineral particles has been shown to be associated with the development of emphysema, but the mechanism of this process is unknown. Because many mineral particles are known to catalyze the formation of active oxygen species in aqueous solution, we hypothesized that mineral particles could oxidatively inactive antiproteinases, leading to an imbalance between protease and antiprotease activities, events similar to those believed to occur with cigarette smoke. To test this hypothesis, human alpha 1-antiproteinase (alpha 1-AP) was incubated with suspensions of freshly ground or aged quartz, and antiproteolytic activity was determined by using porcine pancreatic elastase. Increasing concentrations of quartz were associated with increasing losses of antiproteolytic activity; this effect could be prevented by catalase. Freshly ground quartz was more active than aged quartz. Western blot analysis for alpha 1-AP showed abnormal banding, suggesting that porcine pancreatic elastase-alpha 1-AP complex formation was impaired by silica exposure. Chemical assay of aqueous quartz suspensions demonstrated production of hydrogen peroxide; incubation of alpha 1-AP with hydrogen peroxide caused a dose-dependent loss of antiproteolytic activity, and this also could be prevented by catalase. We conclude that, at least in vitro, quartz can inactivate alpha 1-AP through a hydrogen peroxide-mediated mechanism and that oxidative loss of antiproteinase activity could play a role in mineral dust-induced emphysema.

Adolescent depressed mood and young adult functioning: a longitudinal study

The present study examined two aspects of depressed mood in adolescence: (1) stability across the adolescent years and (2) ability to predict functioning in young adulthood. Participants included 82 Caucasian individuals (46 females and 36 males) who were assessed one time per year for 4 consecutive years during adolescence (mean age at initial assessment = 13.5 years) and again during young adulthood (mean age = 19). The results indicated that depressed mood, as measured by the Children's Depression Inventory (CDI), remained relatively stable across at least 3 consecutive years of data collection during adolescence. In addition, adolescent CDI scores predicted young adult functioning in each of four areas: prosocial competence, self-esteem, externalizing problems, and internalizing problems.

Analysis of immunoglobulin class, IgG subclass and titre of HPA-1a antibodies in alloimmunized mothers giving birth to babies with or without neonatal alloimmune thrombocytopenia

We analysed the titre and isotype composition of antibodies produced by mothers giving birth to babies with or without neonatal alloimmune thrombocytopenic purpura (NAITP) and patients with post-transfusion purpura (PTP). All these individuals produced an antibody specific for the HPA-1a allotype present on the platelet glycoprotein IIb-IIIa (GPIIb-IIIa). Sera from mothers who gave birth to thrombocytopenic babies (group 1, n = 36), non-thrombocytopenic babies (group 2, n = 4) or from PTP patients (group 3, n = 3) were tested by an indirect-ELISA. Results indicated no evident differences in the isotype composition or titre of the antibodies from the three groups of sera. The antibody titre ranged from 1:120 to 1:3500. Antibodies with the IgG1 subclass were present in all sera. Most sera contained IgG1 alone (24/43 sera tested) or in combination with IgG3 (10/43). IgG2 was never present and only three sera showed intermediate reactivity with anti-IgG4 MAb. Few sera (nine sera from groups 1 and 2) were weakly positive when tested with the anti-IgM antibodies. These results suggest that neither the titre nor the isotype composition can be used to predict the severity or the occurrence of thrombocytopenia in newborns.

Pathophysiology of thrombocytopenia associated with HIV infection in homosexual men. A preliminary report

The pathophysiology of HIV associated immune thrombocytopenia (HIV-ITP) and its response to AZT was investigated. Using autologous 111Indium-labelled platelets, platelet kinetic were analysed in two patient groups. Group 1 (untreated) was comprised of 13 patients with HIV-ITP. Group 2 (AZT) was comprised of 6 patients with a history of HIV-ITP prior to starting AZT. These patients were studied following a rise in their platelet count on AZT. Platelet survivals in both groups were shortened compared to controls, however there was no significant difference between the 2 groups. However platelet turnover rates were significantly depressed in Group 1 compared to Group 2 (P less than 0.05) and control values (P less than 0.05). The platelet count correlated with platelet turnover in Group 1 but not in AZT treated patients. Thus patients with HIV-ITP appear to have both shortened survivals and suppressed platelet production. The mechanism of the latter is unknown, but the increased turnover rate seen with AZT suggests it is a direct or indirect effect of the HIV virus.

Molested as children: a hidden contribution to substance abuse?

A history of child sexual victimization may be much more prevalent among substance abusers than previously suspected and may be commonly missed if not assessed directly in every patient. The rates of reporting child sexual abuse among inpatient substance abusers were compared before and after the question was routinely asked in a treatment program. Before routine inquiry, 4% of men and 20% of women disclosed such abuse but after routine inquiries began the rates for adult men quadrupled, up to 42% of the teenaged boys reported such abuse, about 75% of adult women admitted such abuse, and 71 to 90% of teenaged girls disclosed histories of child sexual abuse. Unresolved issues from childhood sexual abuse may be a hidden factor underlying much substance abuse and if not treated may lead to rapid relapse.

Aggressive combination therapy in the successful management of life-threatening intracranial hemorrhage in a patient with idiopathic thrombocytopenic purpura

We describe acute therapy for a 13-year-old female from Panama with chronic idiopathic thrombocytopenia purpura (ITP) refractory to steroids, splenectomy, vinca alkaloids, and azathioprine. She presented with neurologic deterioration from a posterior fossa intracranial hemorrhage (ICH). This followed a 3-month history of severe dysfunctional uterine bleeding, progressive from menarche, which had required multiple red cell transfusions. Steroid and vinblastine therapy and transfusion of 40 U of platelets failed to increase the platelet count above 10,000/microliter. Development of a second larger ICH (frontal) produced morbid increase in intracranial pressure that necessitated neurosurgical decompression. Plasma exchange and colloid repletion with intravenous gamma globulin (1 g/kg) and an infusion of 20 U of platelets resulted in a transient rise in platelet count to 160,000/microliter, permitting surgery without bleeding. Danazol (800 mg/day) and conjugated estrogen (Premarin 25 mg/day) were begun to control the uterine bleeding. Intensive plasma exchange and i.v. IgG infusions were continued daily for 24 days, then twice weekly for several weeks. Platelet-bound IgG decreased almost 500% over the first 10 days of therapy, and platelets increased dramatically to 600,000/microliter after 3 weeks of therapy. The patient has remained amenorrheic with a normal platelet count for more than 24 months on daily danazol therapy and monthly infusions of i.v. IgG (0.4 g/kg/dose).

Antibodies as specific renin inhibitors: studies with polyclonal and monoclonal antibodies and Fab fragments

The use of antirenin antibody and Fab may provide a more specific physiologic tool and potential therapeutic agent than the existing pharmacologic inhibitors. The antibody combining site, by virtue of its larger size than organic compounds, has the capacity for a larger number of intramolecular contacts with its ligands, thus allowing increased selectivity and affinity. Renin-specific Fab obtained through immunization with purified dog renal renin has been studied. Fab had no effect on blood pressure in the sodium replete conscious dog but induced systemic hypotensive responses in the sodium deplete animal or during acute renovascular hypertension. These responses were accompanied with complete suppression of plasma renin and angiotensin II levels. The vasodepressor responses of Fab were comparable to the converting enzyme inhibitor, teprotide. However, the latter induced a greater renal vasodilator effect. Since antibodies and their fragments derived from immune sera are limited in their application to physiologic study with respect to lack of homogeneity, reproducibility and limitation of quantity, we obtained monoclonal antibodies to purified human renal renin. Fusion HR3 yielded 14 renin-antibody secreting clones. Six clones have been isolated and characterized. Isotypes include IgG1 and IgM. Kd's range from 6 X 10(-9) to 7.5 X 10(-10)M renin concentration. Five clones produce antibodies with antienzymatic activity. IC50's of these antibodies range from 1 X 10(-6) to 6 X 10(-8)M. All antibodies are renin-specific and do not bind several nonrenin enzymes and proteins examined. They are also highly species specific, i.e., do not crossreact with mouse, dog, bovine or rat renins but recognize hog renin. These catalytic-site directed antibodies may be highly potent and specific tools for physiologic studies in subhuman primates and man.

Noninvasive measurement of cardiac pressures by induced ventricular wall resonance: preliminary results in the dog

Experiments in the excised dog heart and in live dogs are presented wherein a method of induced right ventricular wall resonance has been utlized to estimate the pressure in the right ventricle of the heart. Externally induced cardiac wall vibrations produced low frequency signals which, when subjected to spectrum analysis and coherent signal processing, permitted close approximation of static pressures and wave forms in the right ventricle at normal and hypertensive levels.