Repetitive endoscopic drainage as initial intervention is safe and effective for early treatment of pancreatic necrotic collections

BACKGROUND

While endoscopic step-up approach with delayed drainage (more than 28 days from diagnosis) was shown to produce the best outcomes in the treatment of pancreatic walled-off necrosis (WON), we assessed our single centre experience of early versus delayed endoscopic drainage of pancreatic necrotic collections.

METHODS

Patients who underwent endoscopic drainage of pancreatic necrotic collections between 2011 and 2022 under Monash Health were identified. They were excluded if below 18 years old or their follow up data were missing. The included patients' medical records, pathology results, and imaging findings were retrospectively reviewed.

RESULTS

A total of 60 patients were included. 31.58% required percutaneous drainage and 15% received either endoscopic or surgical necrosectomy. The disease related mortality was 8.47% and the average length of stay (LOS) was 70.92 days. No significant difference was shown in disease-related mortality (10.5% vs. 7.5%, P = 0.697) or LOS (75.35 vs. 68.7, P = 0.644) between early and delayed drainage cohorts, but patients who received early drainage have higher qSOFA score on the day of drainage (2 vs. 0, P = 0.004).

DISCUSSION

Repetitive endoscopic drainage with selective percutaneous drainage is effective in the management of pancreatic necrotic collections. Early drainage should be considered in patients who developed severe sepsis.

Identifying the real-world challenges of dysplasia surveillance in inflammatory bowel disease: a retrospective cohort study in a tertiary health network

BACKGROUND

Dysplasia surveillance in inflammatory bowel disease (IBD) is often suboptimal and deviates from guidelines.

AIMS

To assess dysplasia surveillance behaviours and adherence to guidelines amongst a large tertiary teaching health network with a specialised IBD unit to identify areas where dysplasia surveillance could be improved.

METHODS

A retrospective audit of IBD surveillance colonoscopy practice over an 18-month period was performed using the Provation Endoscopy Database and the hospital's primary sclerosing cholangitis database.

RESULTS

The audit identified 115 dysplasia surveillance colonoscopies. A total of 37% of index dysplasia colonoscopies were outside recommended guidelines. A total of 10% had inadequate bowel preparation and only 40% had excellent bowel preparation. A total of 28% of patients underwent dye-based chromoendoscopy and 69% underwent high-definition white-light endoscopy. Dye chromoendoscopy was more likely to be used by IBD specialists than interventional endoscopists (P = 0.008) and other endoscopists (P = 0.004). Only IBD specialists and interventional endoscopists used dye chromoendoscopy. Dysplasia or colorectal cancer was detected in 3.4% of the colonoscopies. Overall, the several dysplasia examinations were lower than expected.

CONCLUSIONS

Dysplasia surveillance in the IBD population remains an area of improvement given the current national guidelines. IBD specialists are more likely to perform dye chromoendoscopy than other endoscopists/gastroenterologists. Dysplasia rates in this real-world contemporary setting are less than expected in historical studies and may represent improvements in IBD management principles and medications.

Small mammals reduce activity during high moon illumination under risk of predation by introduced predators

Predation influences prey survival and drives evolution of anti-predator behaviour. Anti-predator strategies by prey are stimulated by direct encounters with predators, but also by exposure to indicators of risk such as moonlight illumination and vegetation cover. Many prey species will suffer increased risk on moonlit nights, but risk may be reduced by the presence of dense vegetation. Determining the role of vegetation in reducing perceived risk is important, especially given predictions of increased global wildfire, which consumes vegetation and increases predation. We used remote cameras in southeastern Australia to compare support for the predation risk and habitat-mediated predation risk hypotheses. We examined the influence of moonlight and understorey cover on seven 20-2500 g mammalian prey species and two introduced predators, red foxes and feral cats. Activity of all prey species reduced by 40-70% with increasing moonlight, while one species (bush rat) reduced activity in response to increasing moonlight more sharply in low compared to high understorey cover. Neither predator responded to moonlight. Our findings supported the predation risk hypothesis and provided limited support for the habitat-mediated predation risk hypothesis. For prey, perceived costs of increased predation risk on moonlit nights outweighed any benefits of a brighter foraging environment.

Optogenetic Inhibition of Rho1-Mediated Actomyosin Contractility Coupled with Measurement of Epithelial Tension in Drosophila Embryos

Contractile forces generated by actin and non-muscle myosin II ("actomyosin contractility") are critical for morphological changes of cells and tissues at multiple length scales, such as cell division, cell migration, epithelial folding, and branching morphogenesis. An in-depth understanding of the role of actomyosin contractility in morphogenesis requires approaches that allow the rapid inactivation of actomyosin, which is difficult to achieve using conventional genetic or pharmacological approaches. The presented protocol demonstrates the use of a CRY2-CIBN based optogenetic dimerization system, Opto-Rho1DN, to inhibit actomyosin contractility in Drosophila embryos with precise temporal and spatial controls. In this system, CRY2 is fused to the dominant negative form of Rho1 (Rho1DN), whereas CIBN is anchored to the plasma membrane. Blue light-mediated dimerization of CRY2 and CIBN results in rapid translocation of Rho1DN from the cytoplasm to the plasma membrane, where it inactivates actomyosin by inhibiting endogenous Rho1. In addition, this article presents a detailed protocol for coupling Opto-Rho1DN-mediated inactivation of actomyosin with laser ablation to investigate the role of actomyosin in generating epithelial tension during Drosophila ventral furrow formation. This protocol can be applied to many other morphological processes that involve actomyosin contractility in Drosophila embryos with minimal modifications. Overall, this optogenetic tool is a powerful approach to dissect the function of actomyosin contractility in controlling tissue mechanics during dynamic tissue remodeling.

An optogenetic tool to inhibit RhoA in Drosophila embryos

We describe a protocol for optogenetic inhibition of the small GTPase Rho1 (RhoA) in Drosophila embryos, which allows rapid and spatially confined inactivation of Rho1 and Rho1-mediated actomyosin contractility. We provide step-by-step instruction for optogenetic manipulations of Drosophila embryos using confocal and multiphoton imaging systems. This tool is useful for determining the site- and stage-specific function of Rho1 in Drosophila embryos and for studying the immediate tissue response to acute elimination of cellular contractility. For complete details on the use and execution of this protocol, please refer to Guo et al. (2022).1.

KRAS G12D Mutation Subtype in Pancreatic Ductal Adenocarcinoma: Does It Influence Prognosis or Stage of Disease at Presentation?

Background: KRAS G12D mutation subtype is present in over 40% of pancreatic ductal adenocarcinoma (PDAC), one of the leading global causes of cancer death. This retrospective cohort study aims to investigate whether detection of the KRAS G12D mutation subtype in PDAC patients is a determinant of prognosis across all stages of disease. Methods: We reviewed the medical records of 231 patients presenting with PDAC at a large tertiary hospital, and compared survival using the Kaplan Meier, log-rank test and Cox proportional hazards regression model. Results: KRAS G12D mutation subtype was not significantly associated with poorer survival compared across the whole population of PDAC patients (p = 0.107; HR 1.293 95% CI (0.946-1.767)). However, KRAS G12D patients who were resectable had a shorter median survival time of 356 days compared to all other genotypes (median survival 810 days) (p = 0.019; HR 1.991 95% CI (1.121-3.537)). Conclusions: KRAS G12D patients who were resectable at diagnosis had shorter survival compared to all other PDAC patients. These data suggest that KRAS G12D may be a clinically useful prognostic biomarker of PDAC.

An unusual case of multiple gastrointestinal stromal tumors in the small bowel presenting as occult and overt gastrointestinal bleeding

We present a case report of a 59‐year‐old woman with multiple gastrointestinal stromal tumors as a cause of gastrointestinal bleeding. She initially presented with recurrent iron deficiency anemia and subsequent gastrointestinal bleeding over 10 years. An initial angiodysplastic lesion was identified, treated, and spot tattooed. Recurrent symptoms occurred leading to repeat investigations with a further subepithelial lesion with ulceration being identified. Computerized tomography enterography subsequently revealed an ileal intraluminal enhancing lesion, and she was referred to surgery. Surgical resection was ultimately performed, and multiple lesions were found to be present with histology revealing multiple gastrointestinal stromal tumors.

Optogenetic control of the Bicoid morphogen reveals fast and slow modes of gap gene regulation

Developmental patterning networks are regulated by multiple inputs and feedback connections that rapidly reshape gene expression, limiting the information that can be gained solely from slow genetic perturbations. Here we show that fast optogenetic stimuli, real-time transcriptional reporters, and a simplified genetic background can be combined to reveal the kinetics of gene expression downstream of a developmental transcription factor in vivo. We engineer light-controlled versions of the Bicoid transcription factor and study their effects on downstream gap genes in embryos. Our results recapitulate known relationships, including rapid Bicoid-dependent transcription of giant and hunchback and delayed repression of Krüppel. In addition, we find that the posterior pattern of knirps exhibits a quick but inverted response to Bicoid perturbation, suggesting a noncanonical role for Bicoid in directly suppressing knirps transcription. Acute modulation of transcription factor concentration while recording output gene activity represents a powerful approach for studying developmental gene networks in vivo.

Optogenetic inhibition of actomyosin reveals mechanical bistability of the mesoderm epithelium during Drosophila mesoderm invagination

Apical constriction driven by actin and non-muscle myosin II (actomyosin) provides a well-conserved mechanism to mediate epithelial folding. It remains unclear how contractile forces near the apical surface of a cell sheet drive out-of-the-plane bending of the sheet and whether myosin contractility is required throughout folding. By optogenetic-mediated acute inhibition of actomyosin, we find that during Drosophila mesoderm invagination, actomyosin contractility is critical to prevent tissue relaxation during the early, ‘priming’ stage of folding but is dispensable for the actual folding step after the tissue passes through a stereotyped transitional configuration. This binary response suggests that Drosophila mesoderm is mechanically bistable during gastrulation. Computer modeling analysis demonstrates that the binary tissue response to actomyosin inhibition can be recapitulated in the simulated epithelium that undergoes buckling-like deformation jointly mediated by apical constriction in the mesoderm and in-plane compression generated by apicobasal shrinkage of the surrounding ectoderm. Interestingly, comparison between wild-type and snail mutants that fail to specify the mesoderm demonstrates that the lateral ectoderm undergoes apicobasal shrinkage during gastrulation independently of mesoderm invagination. We propose that Drosophila mesoderm invagination is achieved through an interplay between local apical constriction and mechanical bistability of the epithelium that facilitates epithelial buckling.

Endoscopic ultrasound-guided gallbladder and bile duct drainage with lumen apposing metal stent: A large multicenter cohort (with videos)

BACKGROUND AND AIM

Cholecystectomy and endoscopic retrograde cholangiopancreatography are the gold standard for managing acute cholecystitis and malignant biliary obstruction, respectively. Recent advances in therapeutic endoscopic ultrasound (EUS) have provided alternatives for managing patients in whom these approaches fail, namely, EUS-guided gallbladder drainage (EUS-GB) and EUS-guided bile duct drainage (EUS-BD). We aimed to assess the technical and clinical success of these techniques in the largest multicenter cohort published to date.

METHODS

A retrospective, multicenter, observational study involving 17 centers across Australia and New Zealand was conducted. All patients who had EUS-GB or EUS-BD performed in a participating center using a lumen apposing metal stent between 2016 and 2020 were included. Primary outcome was technical success, defined as intra-procedural successful drainage. Secondary outcomes included clinical success and 30-day mortality.

RESULTS

One hundred and fifteen patients underwent EUS-GB (n = 49) or EUS-BD (n = 66). EUS-GB was technically successful in 47 (95.9%) while EUS-BD was successful in 60 (90.9%). All failed cases were due to maldeployment of the distal flange outside of the targeted lumen. Clinical success of EUS-GB was achieved in 39 (79.6%). No patients required subsequent cholecystectomy. Clinical success of EUS-BD was achieved in 52 (78.8 %). Thirty-day mortality was 14.3% for EUS-GB and 12.1% for EUS-BD.

CONCLUSIONS

EUS-guided gallbladder drainage and EUS-BD are promising alternatives for managing nonsurgical candidates with cholecystitis and malignant biliary obstruction following failed endoscopic retrograde pancreatography. Both techniques delivered high technical success with acceptable clinical success. Further research is needed to investigate the gap between technical and clinical success.

EUS-FNA Biopsies to Guide Precision Medicine in Pancreatic Cancer: Results of a Pilot Study to Identify KRAS Wild-Type Tumours for Targeted Therapy

Background

Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer death and lacks effective treatment options. Diagnostic endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) biopsies represent an appealing source of material for molecular analysis to inform targeted therapy, as they are often the only available tissue for patients presenting with PDAC irrespective of disease stage. However, EUS-FNA biopsies are typically not used to screen for precision medicine studies due to concerns about low tissue yield and quality. Epidermal growth factor receptor (EGFR) inhibition has shown promise in clinical trials of unselected patients with advanced pancreatic cancer, but has not been prospectively tested in KRAS wild-type patients. Here, we examine the clinical utility of EUS-FNA biopsies for molecular screening of KRAS wild-type PDAC patients for targeted anti-EGFR therapy to assess the feasibility of this approach.

Patients and Methods

Fresh frozen EUS-FNA or surgical biopsies from PDAC patient tumours were used to screen for KRAS mutations. Eligible patients with recurrent, locally advanced, or metastatic KRAS wild-type status who had received at least one prior line of chemotherapy were enrolled in a pilot study (ACTRN12617000540314) and treated with panitumumab at 6mg/kg intravenously every 2 weeks until progression or unacceptable toxicity. The primary endpoint was 4-month progression-free survival (PFS).

Results

275 patient biopsies were screened for KRAS mutations, which were detected in 88.3% of patient samples. 8 eligible KRAS wild-type patients were enrolled onto the interventional study between November 2017 and December 2020 and treated with panitumumab. 4-month PFS was 14.3% with no objective tumour responses observed. The only grade 3/4 treatment related toxicity observed was hypomagnesaemia.

Conclusions

This study demonstrates proof-of-principle feasibility to molecularly screen patients with pancreatic cancer for targeted therapies, and confirms diagnostic EUS-FNA biopsies as a reliable source of tumour material for molecular analysis. Single agent panitumumab was safe and tolerable but led to no objective tumour responses in this population.

The EUS molecular evaluation of pancreatic cancer: A prospective multicenter cohort trial

Background and Objectives:

Patients with locally advanced or metastatic pancreatic ductal adenocarcinoma (A-PDAC) are not candidates for surgical resection and are often offered palliative chemotherapy. The ready availability of a safe and effective tumor sampling technique to provide material for both diagnosis and comprehensive genetic profiling is critical for informing precision medicine in A-PDAC, thus potentially increasing survival. The aim of this study is to examine the feasibility and benefits of routine comprehensive genomic profiling (CGP) of A-PDAC using EUS-FNA material.

Methods:

This is a prospective cohort study to test the clinical utility of fresh frozen or archival EUS-FNA samples in providing genetic material for CGP. The results of the CGP will be reviewed at a molecular tumor board. The proportion of participants that have a change in their treatment recommendations based on their individual genomic profiling will be assessed. Correlations between CGP and stage, prognosis, response to treatment and overall survival will also be investigated. This study will open to recruitment in 2020, with a target accrual of 150 A-PDAC patients within 36 months, with a 2-year follow-up. It is expected that the majority of participants will be those who have already consented for their tissue to be biobanked in the Victorian Pancreatic Cancer Biobank at the time of diagnostic EUS-FNA. Patients without archival or biobanked material that is suitable for CGP may be offered a EUS-FNA procedure for the purposes of obtaining fresh frozen material.

Discussion:

This trial is expected to provide crucial data regarding the feasibility of routine CGP of A-PDAC using EUS-FNA material. It will also provide important information about the impact of this methodology on patients’ survival.

Adenosine triphosphate bioluminescence to validate decontamination of endoscopes

The reports of outbreaks involving carbapenemase-resistant Enterobacteriaceae (CRE) associated with gastrointestinal endoscopy prompted a review and study of a novel method of assessing cleaning. This study assessed adenosine triphosphate (ATP) bioluminescence to demonstrate cleanliness prior to endoscopy. ATP testing was compared with microbiological monitoring for 127 endoscopes. Samples were taken after cleaning, reprocessing and storage, but immediately before the endoscopy procedure. We recommend implementing ATP testing prior to endoscopy procedures as an alternative to microbiological testing at periodic intervals. ATP testing provides a convenient assessment of endoscopy hygiene to demonstrate safety and quality assurance.

Endoscopic ultrasound-guided fine-needle aspirate-derived preclinical pancreatic cancer models reveal panitumumab sensitivity in KRAS wild-type tumors

Pancreatic cancer (PC) is largely refractory to existing therapies used in unselected patient trials, thus emphasizing the pressing need for new approaches for patient selection in personalized medicine. KRAS mutations occur in 90% of PC patients and confer resistance to epidermal growth factor receptor (EGFR) inhibitors (e.g., panitumumab), suggesting that KRAS wild-type PC patients may benefit from targeted panitumumab therapy. Here, we use tumor tissue procured by endoscopic ultrasound-guided fine-needle aspirate (EUS-FNA) to compare the in vivo sensitivity in patient-derived xenografts (PDXs) of KRAS wild-type and mutant PC tumors to panitumumab, and to profile the molecular signature of these tumors in patients with metastatic or localized disease. Specifically, RNASeq of EUS-FNA-derived tumor RNA from localized (n = 20) and metastatic (n = 20) PC cases revealed a comparable transcriptome profile. Screening the KRAS mutation status of tumor genomic DNA obtained from EUS-FNAs stratified PC patients into either KRAS wild-type or mutant cohorts, and the engraftment of representative KRAS wild-type and mutant EUS-FNA tumor samples into NOD/SCID mice revealed that the growth of KRAS wild-type, but not mutant, PDXs was selectively suppressed with panitumumab. Furthermore, in silico transcriptome interrogation of The Cancer Genome Atlas (TCGA)-derived KRAS wild-type (n = 38) and mutant (n = 132) PC tumors revealed 391 differentially expressed genes. Taken together, our study validates EUS-FNA for the application of a novel translational pipeline comprising KRAS mutation screening and PDXs, applicable to all PC patients, to evaluate personalized anti-EGFR therapy in patients with KRAS wild-type tumors.

USING ADENOSINETRIPHOSPHATE BIOLUMINESCENCE TO VALIDATE DECONTAMINATION FOR DUODENOSCOPES

Reports of outbreaks involving Carbapenemase resistant Enterobacteriaceae have been associated with gastrointestinal endoscopy. We used Adenosinetriphosphate (ATP) bioluminescence to demonstrate cleanliness prior to Endoscopic Retrograde Cholangiopancreatography (ERCP). We compared ATP testing with microbiological monitoring for 40 duodenoscopes. ATP testing of duodenoscopes prior to ERCP procedures provided a timely marker of safety and quality.

PH Domain-Arf G Protein Interactions Localize the Arf-GEF Steppke for Cleavage Furrow Regulation in Drosophila

The recruitment of GDP/GTP exchange factors (GEFs) to specific subcellular sites dictates where they activate small G proteins for the regulation of various cellular processes. Cytohesins are a conserved family of plasma membrane GEFs for Arf small G proteins that regulate endocytosis. Analyses of mammalian cytohesins have identified a number of recruitment mechanisms for these multi-domain proteins, but the conservation and developmental roles for these mechanisms are unclear. Here, we report how the pleckstrin homology (PH) domain of the Drosophila cytohesin Steppke affects its localization and activity at cleavage furrows of the early embryo. We found that the PH domain is necessary for Steppke furrow localization, and for it to regulate furrow structure. However, the PH domain was not sufficient for the localization. Next, we examined the role of conserved PH domain amino acid residues that are required for mammalian cytohesins to bind PIP3 or GTP-bound Arf G proteins. We confirmed that the Steppke PH domain preferentially binds PIP3 in vitro through a conserved mechanism. However, disruption of residues for PIP3 binding had no apparent effect on GFP-Steppke localization and effects. Rather, residues for binding to GTP-bound Arf G proteins made major contributions to this Steppke localization and activity. By analyzing GFP-tagged Arf and Arf-like small G proteins, we found that Arf1-GFP, Arf6-GFP and Arl4-GFP, but not Arf4-GFP, localized to furrows. However, analyses of embryos depleted of Arf1, Arf6 or Arl4 revealed either earlier defects than occur in embryos depleted of Steppke, or no detectable furrow defects, possibly because of redundancies, and thus it was difficult to assess how individual Arf small G proteins affect Steppke. Nonetheless, our data show that the Steppke PH domain and its conserved residues for binding to GTP-bound Arf G proteins have substantial effects on Steppke localization and activity in early Drosophila embryos.

Passive mechanical forces control cell-shape change during Drosophila ventral furrow formation

During Drosophila gastrulation, the ventral mesodermal cells constrict their apices, undergo a series of coordinated cell-shape changes to form a ventral furrow (VF) and are subsequently internalized. Although it has been well documented that apical constriction is necessary for VF formation, the mechanism by which apical constriction transmits forces throughout the bulk tissue of the cell remains poorly understood. In this work, we develop a computational vertex model to investigate the role of the passive mechanical properties of the cellular blastoderm during gastrulation. We introduce to our knowledge novel data that confirm that the volume of apically constricting cells is conserved throughout the entire course of invagination. We show that maintenance of this constant volume is sufficient to generate invagination as a passive response to apical constriction when it is combined with region-specific elasticities in the membranes surrounding individual cells. We find that the specific sequence of cell-shape changes during VF formation is critically controlled by the stiffness of the lateral and basal membrane surfaces. In particular, our model demonstrates that a transition in basal rigidity is sufficient to drive VF formation along the same sequence of cell-shape change that we observed in the actual embryo, with no active force generation required other than apical constriction.

A mesoscale abscisic acid hormone interactome reveals a dynamic signaling landscape in Arabidopsis

The sesquiterpenoid abscisic acid (ABA) mediates an assortment of responses across a variety of kingdoms including both higher plants and animals. In plants, where most is known, a linear core ABA signaling pathway has been identified. However, the complexity of ABA-dependent gene expression suggests that ABA functions through an intricate network. Here, using systems biology approaches that focused on genes transcriptionally regulated by ABA, we defined an ABA signaling network of over 500 interactions among 138 proteins. This map greatly expanded ABA core signaling but was still manageable for systematic analysis. For example, functional analysis was used to identify an ABA module centered on two sucrose nonfermenting (SNF)-like kinases. We also used coexpression analysis of interacting partners within the network to uncover dynamic subnetwork structures in response to different abiotic stresses. This comprehensive ABA resource allows for application of approaches to understanding ABA functions in higher plants.

Measuring plaque in clinical trials: index or weight?

AIM

To explore the possibility of using plaque weight rather than plaque index as a more objective, clinical outcome measure in periodontal clinical trials.

MATERIALS AND METHODS

The study initially recruited 12 healthy volunteers who abstained from tooth cleaning for 24 h on each of the three occasions and then for 48 h on each of a further three occasions to accumulate plaque. On a further three visits, the subjects abstained from tooth cleaning for 24 h and then brushed with a powered toothbrush for 2 min. A split-mouth design with target teeth was adopted and plaque was first scored separately on each side of the mouth using the Turesky modification of the Quigley and Hein plaque index. Post-brushing residual plaque was also scored after tooth cleaning. Inter-proximal plaque was dried, removed, pooled and weighed: on one side of the mouth from the entire inter-proximal surfaces; and from beneath the contact points on the contra-lateral side.

RESULTS

Discriminant validity showed the index to have an advantage over weight in discerning between 24- and 48-h plaque deposits, and between 24-h plaque and post-brushing plaque. Test-retest validity confirmed that for repeated plaque growth, variability within subjects was greater than the variability between subjects. There was an association between plaque weight and plaque index although the regression lines were non-linear.

CONCLUSION

There appears to be no significant advantage in using plaque weight in periodontal clinical trials.

Smoking cessation advice for patients with chronic periodontitis

BACKGROUND

There are limited data on the utility of dental professionals in providing smoking cessation counselling in the UK.

OBJECTIVES

The purpose of this study was to determine quit rates for smokers with chronic periodontitis who were referred to a dental hospital for treatment.

MATERIALS AND METHODS

Forty-nine subjects with chronic periodontitis who smoked cigarettes were recruited. All subjects received periodontal treatment and smoking cessation advice as part of an individual, patient-based programme provided by dental hygienists trained in smoking cessation counselling. Smoking cessation interventions included counselling (all patients), and some patients also received nicotine replacement therapy (NRT) and/or Zyban medication. Smoking cessation advice was given at each visit at which periodontal treatment was undertaken (typically four to six visits) over a period of 10-12 weeks. Smoking cessation advice was also given monthly during the programme of supportive periodontal care over the following nine months. Smoking status was recorded at three, six and 12 months and was confirmed with carbon monoxide (CO) monitors and salivary cotinine assays.

RESULTS

Forty-one per cent, 33%, 29% and 25% of patients had stopped smoking at week four, months three, six and 12, respectively. Gender, age, the presence of another smoker in the household, and baseline smoking status (determined using subject-reported pack years of smoking) were not significant predictors of quit success (P < 0.05). Baseline CO levels were significantly associated with quit success, however, and were significantly higher in those subjects who continued to smoke compared to those subjects who were quitters at week four, month three and month six (P < 0.05).

CONCLUSION

Success rates in quitting smoking following smoking cessation advice given as part of a periodontal treatment compared very favourably to national quit rates achieved in specialist smoking cessation clinics. The dental profession has a crucial role to play in smoking cessation counselling, particularly for patients with chronic periodontitis.

Effect of brushing force and time on plaque removal using a powered toothbrush

OBJECTIVES

Primary objective - To determine the effect of varying brushing forces and brushing times upon the plaque-removing efficacy of a powered toothbrush. Secondary objective - to determine the optimum combination of brushing force and time for plaque removal.

MATERIAL AND METHODS

This randomised, single-blind, 16-cell, cross-over trial compared the efficacy of plaque removal of a powered toothbrush (PTB) used with four brushing forces (75, 150, 225 and 300 g) and over four brushing times (30, 60, 120 and 180 s). Twelve volunteers (18-30 years) were recruited and trained to use the Philips/Jordan Sensiflex 2000 PTB, which was modified so that specified forces and times could be recorded. Each subject was asked to abstain from all oral hygiene procedures for 24 hs prior to each brushing event, to allow plaque accumulation. Plaque was recorded using a modified Quigley & Hein index (PI) at six points per tooth before and after each episode of brushing, and the differences in the means (pre- to postbrushing) were compared. Three-way anova was undertaken to compare differences between plaque-removing efficacy for the 16 combinations of force and time. Subjects, brushing time and brushing force were used as fixed effects within the analysis.

RESULTS

All 12 subjects participating completed the 16 combinations of force and time over which plaque removal was assessed. Statistically significant differences in PI reductions were found between different brushing times and forces over all tooth surfaces (p<0.001). The interaction of varying brushing force and brushing time was significant for full mouth (FM) and interproximal (IP) sites (p<0.03). No statistical significance was demonstrated for smooth surface (SS) sites, nor was it detected for the interaction of subjects with brushing force or subjects with brushing time (p>0.05).

CONCLUSION

We conclude that brushing time and brushing force have significant effects upon the level of plaque removal by a PTB, and at 120 s brushing time the improvement in plaque removal with forces in excess of 150 g was negligible.

'Babies don't come with a set of instructions': running support groups for mothers

A successful bid to the health promotion department by an inner city Glasgow GP enabled two health promotion officers to offer support groups to mothers with young children. Jacki Gordon, Robbie Robertson and Margaret Swan describe their approach and how mothers benefited from this additional support.

Distribution of mRNA for the GABA transporter GAT-1 in the rat brain: evidence that GABA uptake is not limited to presynaptic neurons

Cells containing mRNA for the gamma-aminobutyric acid (GABA) transporter GAT-1 were identified in rat brain by in situ hybridisation. They were found in most of the known locations of GABAergic neurons, as defined by the distribution of mRNA for glutamic acid decarboxylase, the synthetic enzyme for GABA. Within the cerebellum there was substantial labelling of basket and stellate cells in the molecular layer, and of Golgi cells but no others in the granule cell layer. Many Purkinje cells were unlabelled while others, particularly in the hemispheres, were moderately labelled. Many of the Purkinje cells negative for GAT-1 mRNA had adjacent intensely labelled small cells whose size and position corresponded to Bergmann glia. Numerical comparison of cells labelling for GAT-1 mRNA and the mRNAs for the two known isoforms of glutamic acid decarboxylase were made on serial sections of cerebral cortex. Cells positive for GAT-1 mRNA were more numerous, indicating that expression of the transporter is not just limited to GABAergic cells and we suggest that it may also be expressed postsynaptically by some non-GABAergic neurons.

THE SWIMMING OF UNIPOLAR CELLS OF SPIRILLUM VOLUTANS: THEORY AND OBSERVATIONS

Bright-field high-speed cinemicrography was employed to record the swimming of six unipolar cells of Spirillum volutans. A complete set of geometrical parameters for each of these six cells, which are of typical but varying dimensions, was measured experimentally. For each cell, the mean swimming linear and angular speeds were measured for a period representing an exact number of flagellar cycles (at least four and up to 12 cycles). Two independent sets of measurements were carried out for each cell, one relating to the trailing and the other to the leading configuration of the flagellar bundle. The geometry of these cells was numerically modelled with curved isoparametric boundary elements (from the measured geometrical parameters), and an existing boundary element method (BEM) program was applied to predict the mean swimming linear and angular speeds. A direct comparison between the experimentally observed swimming speeds and those of the BEM predictions is made. For a typical cell, a direct comparison of the swimming trajectory, in each of the trailing and the leading flagellar configurations, was also included. Previous resistive force theory (RFT) as well as slender body theory (SBT) models are both restricted to somewhat non-realistic 'slender body' geometries, and they both fail to consider swimming kinematics. The present BEM model, however, is applicable to organisms with arbitrary geometry and correctly accounts for swimming kinematics; hence, it agrees better with experimental observations than do the previous models.

Capgras' syndrome presenting with violence following heavy drinking

Two cases of Capgras' syndrome are described in which patients committed serious acts of violence towards family members who had become the subject of delusional misidentification. The cases illustrate some typical features of Capgras' syndrome including its potential for dangerousness. Intoxication with alcohol is proposed as a precipitant for violence in these patients.

Models of lexical access in visual word recognition

This paper reviews the ability of Morton's Logogen model and Becker's Verification model to accommodate RT data from the lexical decision literature. While both of the models can account for the simple effects of word frequency, word context and word repetition, Morton's Logogen model can not account for some of the patterns of additivity and interaction when the effects of stimulus degradation are considered.

An experiment on lexical decision is then reported in which stimulus degradation and repetition are factorially varied; degradation and repetition are shown to be interacting factors. These results are inconsistent with the Verification model but consistent with the Logogen model.

Finally, further versions of both the Logogen and Verification models are considered and possible multiple sources are proposed to account for the effects of degradation, repetition and word frequency.

Sexual and marital problems in a psychiatric out-patient population

The study aimed to identify those patients referred to a psychiatric out-patient clinic who had sexual or marital difficulties and who could be offered help with these problems, although none of the patients had been referred primarily for sexual or marital therapy. The methods of assessment formed a series of filtering devices for screening the sample, and possible reasons for discrepancies in the results are discussed. Twelve per cent of the sample had sexual or marital problems and were offered treatment, and it is suggested that this proportion may be an underestimate of the 'true' frequency of such problems in the sample. Implications of this finding for the provision of treatment resources in the psychiatric out-patient setting are considered.

Intercellular contacts between erythroid precursors in the bone marrow in dyserythropoiesis

The ultrastructure of the cellular interfaces between erythroid precursors has been studied in both congenital and acquired dyserythropoiesis. The types of cell-to-cell contacts found included highly convoluated interdigitating septate-like junctions as well as apparent confluence of the cellular membranes of adjacent erythroid cells. Such findings are not characteristic of the intercellular relationships found in the normal erythroblastic islands. The erythroid plasma membrane modifications are possibly related to the changes in the plasma membranes of erythroid cells known to occur in dyserythropoiesis and their presence may well contribute to the ineffective erythropoiesis with intramedullary cell destruction which characterizes many dyserythropoietic states.