A severe case of disseminated cryptococcosis in a young French bulldog living in South-East Queensland caused by Cryptococcus gattii VGII.

BACKGROUND: Cryptococcus is one of the most common systemic mycosis worldwide, infecting young adults of the large to giant breed dogs. Infection is commonly acquired from the environment via the sinonasal cavity as the main portal of entry. It either remains there, or spreads to the central nervous system (CNS) and the eye (optic nerve and retina) by penetration of the cribriform plate, or haematogenously to other viscera. Lung involvement is uncommon in cats and dogs in contrast to human and equine patients. Whilst there is a wide genetic diversity amongst Cryptococcus neoformans and Cryptococcus gattii isolates along the West Coast and Northern parts of Australia, the molecular diversity of C. gatti is considered very low on the East Coast of Australia, with a huge preponderance of VGI cases. We report on a young small breed brachycephalic dog that presented with extreme gastrointestinal and respiratory signs, but no CNS involvement. It is the first reported case of C. gattii VGII genotype in a companion animal from Queensland. CASE REPORT: A 9-month old female entire French Bulldog presented initially for diarrhoea. Clinical progression was accompanied by the development of respiratory signs, so the patient was referred to a 24 h care facility. Following hospitalisation, the patient became hypoxemic requiring mechanical ventilation. A bronchoalveolar lavage performed antemortem confirmed abundant Cryptococcal spp. Further culturing and genotyping identified the species as Cryptococcus gattii VGII. Post-mortem findings indicated gross gastrointestinal and mesenteric involvement, with possible dissemination to the local mesenteric lymph node and lungs. CONCLUSION: This case describes a rare example of a Cryptococcus spp suspected of disseminating from the gastrointestinal tract to the lungs, without involvement of the CNS. The observation of this finding in a small brachycephalic breed is unusual, and the finding of genotype VGII on the East Coast of Queensland is extremely unusual as there is no prior travel history of the dog or owners. The presence of a miliary lung pattern with primary gastrointestinal disease in a small breed dog warrants adding cryptococcosis to the differential diagnosis.

White matter, cognition and psychotic-like experiences in UK Biobank.

BACKGROUND: Psychotic-like experiences (PLEs) are risk factors for the development of psychiatric conditions like schizophrenia, particularly if associated with distress. As PLEs have been related to alterations in both white matter and cognition, we investigated whether cognition (g-factor and processing speed) mediates the relationship between white matter and PLEs. METHODS: We investigated two independent samples (6170 and 19 891) from the UK Biobank, through path analysis. For both samples, measures of whole-brain fractional anisotropy (gFA) and mean diffusivity (gMD), as indications of white matter microstructure, were derived from probabilistic tractography. For the smaller sample, variables whole-brain white matter network efficiency and microstructure were also derived from structural connectome data. RESULTS: The mediation of cognition on the relationships between white matter properties and PLEs was non-significant. However, lower gFA was associated with having PLEs in combination with distress in the full available sample (standardized ß = -0.053, p = 0.011). Additionally, lower gFA/higher gMD was associated with lower g-factor (standardized ß = 0.049, p < 0.001; standardized ß = -0.027, p = 0.003), and partially mediated by processing speed with a proportion mediated of 7% (p = < 0.001) for gFA and 11% (p < 0.001) for gMD. CONCLUSIONS: We show that lower global white matter microstructure is associated with having PLEs in combination with distress, which suggests a direction of future research that could help clarify how and why individuals progress from subclinical to clinical psychotic symptoms. Furthermore, we replicated that processing speed mediates the relationship between white matter microstructure and g-factor.

The effect of remote ischaemic preconditioning on postoperative cardiac and inflammatory biomarkers in pancreatic surgery: a randomized controlled trial.

BACKGROUND: Cardiac and inflammatory biomarkers have been associated with adverse outcome after major abdominal surgery. This study investigated the effect of remote ischaemic preconditioning (RIPC) on perioperative concentrations of high-sensitive cardiac troponin (hs-cTn) T and interleukin (IL) 6. METHODS: Adult patients scheduled for elective pancreatic surgery between March 2017 and February 2019 were randomized to either three cycles of upper-limb ischaemia and reperfusion (each 5 min) or a sham procedure before surgery. The primary endpoint was the maximum postoperative hs-cTnT concentration within 48 h after surgery. Secondary endpoints were postoperative myocardial injury (PMI), defined as an absolute increase of hs-cTnT of at least 14 ng/l above baseline concentration, maximum concentration of IL-6 within 48 h after surgery and postoperative complications within 30 days of surgery. RESULTS: Of 99 eligible patients, 46 underwent RIPC and 46 a sham procedure. RIPC did not reduce the maximum hs-cTnT concentration after surgery (12.6 ng/l RIPC, 16.6 ng/l controls, P = 0.225), nor did it lessen the incidence of PMI (15/45 RIPC, 18/45 controls, P = 0.375). The maximum postoperative IL-6 concentration was 265 pg/ml after RIPC versus 385 pg/ml in controls (P = 0.108). Postoperative complications occurred in 23 RIPC and 24 control patients respectively. CONCLUSIONS: Remote ischaemic preconditioning did not reduce the maximum postoperative hs-cTnT concentration. Postoperative myocardial injury, IL-6 concentrations and postoperative complications were similar between RIPC patients and controls. TRIAL REGISTRATION: Clinicaltrials.gov identifier NCT03460938.

[Mental health in Bonaire - an inspiration for the Dutch New Mental Health Movement]. / De ggz in Bonaire - een inspiratie voor de beweging 'de nieuwe ggz'.

BACKGROUND: In 2010 the bes-islands in the Caribbean became a special municipality of the Netherlands. Healthcare was upgraded to match Dutch standards over a short period of time. With a population of 15,518 inhabitants in 2010 (19,408 in 2016), Bonaire received its own fact-team (flexible assertive community treatment). It subsequently became a unique experiment for the Dutch New Mental Health Movement.
AIM: To describe the development of a modern mental health care system in a limited geographic area.
METHOD: Site visitation, interviews and analysis of historical data sources.
RESULTS: The local mental health team takes integral responsibility for all the mh care needs in Bonaire. There is no intricate diagnostic referral system. Consultation access lines are short. The team was able to dramatically reduce the need for hospitalization. Collaboration with the somatic hospital and general practitioners runs smoothly and the facilities offer complementary care. Societal integration is insured due to mental health professionals living interspersed in the neighborhood, the low threshold allowing them to respond to signals efficiently. There is a natural development of the following three domains of care: reduction of symptoms, societal participation and personal remission.
CONCLUSION: Integrated mental health services in a geographically small area, as presented by the Dutch New Mental Health Movement, enables the possibility of recovery oriented care.

A randomized controlled trial evaluating the efficacy of a 67% sodium bicarbonate toothpaste on gingivitis.

INTRODUCTION: In previous studies, toothpastes with high levels of sodium bicarbonate (>50%) have reduced gingival inflammation and oral malodour. This study compared the effects of brushing for 6 weeks with 67% (test group) or 0% (control group) sodium bicarbonate toothpaste on gingival health. METHODS: This was a single-centre, single examiner-blind, randomized, controlled, two-treatment, parallel-group study. Eligible subjects (≥18 years) had ≥20 gradable teeth, mild-to-moderate gingivitis, a positive response to bleeding on brushing and ≥20 bleeding sites. The primary objective was to compare the number of bleeding sites following twice-daily use of 67% sodium bicarbonate toothpaste or 0% sodium bicarbonate toothpaste after 6 weeks. Secondary endpoints included Modified Gingival Index (MGI), Bleeding Index (BI) and volatile sulphur compounds (VSC), assessed after 6 weeks. Safety was assessed by treatment-emergent oral soft tissue abnormalities and adverse events. RESULTS: Of 148 patients randomized (74 to each treatment), 66 (89.2%) completed the study in the test group, compared with 69 (93.2%) in the control group. Compared with the control group, the test group had a significant reduction in the number of bleeding sites at Week 6 (absolute difference - 11.0 [-14.0, -8.0], P < 0.0001; relative difference - 25.4%), together with significant reductions in MGI and BI (both P < 0.0001). Although the median reductions from baseline for VSC were numerically greater in the test group, the difference did not reach statistical significance (P = 0.9701). CONCLUSIONS: This 67% sodium bicarbonate toothpaste provided statistically significant improvements in gingival health and bleeding after 6 weeks of use.

Effect of toothbrushing duration and dentifrice quantity on enamel remineralisation: An in situ randomized clinical trial.

OBJECTIVES: The influence of toothbrushing duration and dentifrice quantity on fluoride efficacy against dental caries is poorly understood. This study investigated effects of these two oral hygiene factors on enamel remineralisation (measured as surface microhardness recovery [SMHR]), enamel fluoride uptake (EFU), and net acid resistance (NAR) post-remineralisation in a randomized clinical study using an in situ caries model. METHODS: Subjects (n=63) wore their partial dentures holding partially demineralised human enamel specimens and brushed twice-daily for two weeks, following each of five regimens: brushing for 120 or 45s with 1.5g of 1150ppm F (as NaF) dentifrice; for 120 or 45s with 0.5g of this dentifrice; and for 120s with 1.5g of 250ppm F (NaF) dentifrice. RESULTS: Comparing brushing for 120s against brushing for 45s, SMHR and EFU increased by 20.0% and 26.9% respectively when 1.5g dentifrice was used; and by 22.8% and 19.9% respectively when 0.5g dentifrice was used. Comparing brushing with 1.5g against brushing with 0.5g dentifrice, SMHR and EFU increased by 35.3% and 51.3% respectively when brushing for 120s, and by 38.4% and 43.0% respectively when brushing for 45s. Increasing brushing duration and dentifrice quantity also increased the NAR value. The effects of these two oral hygiene factors on SMHR, EFU, and NAR were statistically significant (p<0.05 in all cases). CONCLUSION: Brushing duration and dentifrice quantity have the potential to influence the anti-caries effectiveness of fluoride dentifrices. Study NCT01563172 on ClinicalTrials.gov. CLINICAL SIGNIFICANCE: The effect of two key oral hygiene regimen factors - toothbrushing duration and dentifrice quantity - on fluoride's anticaries effectiveness is unclear. This 2-week home-use in situ remineralisation clinical study showed both these factors can influence fluoride bioactivity, and so can potentially affect fluoride's ability to protect against caries.

A randomised clinical study to evaluate the efficacy of alcohol-free or alcohol-containing mouthrinses with chlorhexidine on gingival bleeding.

OBJECTIVES: Gingival bleeding following twice-daily use of 0.2% w/v chlorhexidine digluconate mouthrinse with and without alcohol (0.2% CHX-alcohol; 0.2% CHX-alcohol-free, respectively) and brushing with a standard fluoride toothpaste was compared to brushing alone. METHODS: Three hundred and nineteen subjects with mild-to-moderate gingivitis (with ≥16 gradable permanent teeth including four molars, bleeding after brushing and ≥20 bleeding sites) completed this randomised, examiner-blinded, parallel-group study. A prophylaxis was performed at baseline. Gingival Severity Index (GSI; primary objective), Gingival Index (GI) and Plaque Index (PI) were assessed at baseline and after 6 weeks of treatment. Adverse events (AEs) were recorded throughout the study. RESULTS: Between treatment differences at week 6 demonstrated significantly lower GSI for the 0.2% CHX-alcohol and 0.2% CHX-alcohol-free groups compared to brushing alone (primary endpoint; treatment difference -0.061 [95% CI -0.081, -0.041] and -0.070 [95% CI -0.090, -0.050], respectively; both p <0.0001). There were also significant reductions in GI and PI for the 0.2% CHX-alcohol and 0.2% CHX-alcohol-free groups compared to brushing alone (all p <0.0001). The proportion of subjects reporting ≥1 treatment-related adverse events (TRAEs) was 27.8% (0.2% CHX-alcohol), 24.8% (0.2% CHX-alcohol-free) and 3.7% (brushing alone). CONCLUSIONS: Chlorhexidine mouthrinse with or without alcohol as an adjunct to brushing with regular fluoride toothpaste significantly reduces bleeding scores, plaque and gingival inflammation compared to brushing alone. TRAEs are characteristic of those associated with the use of chlorhexidine and are similar for both mouthrinses.

Dose-response effect of fluoride dentifrice on remineralisation and further demineralisation of erosive lesions: A randomised in situ clinical study.

OBJECTIVE: The objective was to evaluate the ability of fluoride in a conventional, non-specialised sodium fluoride-silica dentifrice to promote tooth remineralisation and enamel fluoride uptake (EFU), and assess the resistance of the newly formed mineral to attack by dietary acid, across the concentration range used in mass-market dentifrices. METHODS: Subjects wore a palatal appliance containing eight polished bovine enamel specimens, each including an early erosive lesion. In a randomised full-crossover sequence, 62 healthy subjects were treated with dentifrices containing four different fluoride concentrations: no fluoride; 250ppm, 1150ppm and 1426ppm fluoride. At each treatment visit, under supervision, subjects brushed with 1.5g dentifrice and rinsed once while wearing the appliance; the appliance was removed after a 4-h remineralisation period and effects on the enamel specimens determined. The primary efficacy variable was surface microhardness recovery (SMHR); others included EFU, relative erosion resistance (RER) and comparative erosion resistance. RESULTS: Highly significant linear and, with the exception of SMHR, quadratic dose-response relationships were observed between all efficacy variables and fluoride concentration. For SMHR, EFU and RER, values for the different fluoride concentrations were statistically resolved from one another, with the exception of the two highest fluoride concentrations. The degree of remineralisation and the acid resistance of enamel after treatment were closely related to EFU. CONCLUSION: After a single brushing, conventional non-specialised sodium fluoride-silica dentifrices promoted remineralisation of early enamel lesions, and imparted increased acid-resistance to the enamel surface, in a dose-dependent manner at least up to 1500ppm fluoride. CLINICAL SIGNIFICANCE: Enamel erosive tissue loss is an increasing concern, associated with modern diets. This study demonstrated that sodium fluoride, in a conventional non-specialised dentifrice formulation, can promote repair of the earliest stages of enamel erosion after a single application, in a dose-dependent fashion across the fluoride concentration range used in mass-market dentifrices. This study is registered in the GlaxoSmithKline Study Register (ID RH01299), available at: www.gsk-clinicalstudyregister.com/study/RH01299.

Mindfulness, physical impairment and psychological well-being in people with amyotrophic lateral sclerosis.

OBJECTIVE: Mindfulness is the process of actively making new distinctions, rather than relying on habitual or automatic categorisations from the past. Mindfulness has been positively associated with physical well-being, better recovery rates from disease or infections, pain reduction and overall quality of life (QOL). Amyotrophic lateral sclerosis (ALS) is a rare, progressive and fatal neurodegenerative disease, clinically characterised by progressively increasing weakness leading to death, usually within five years. There is presently no cure for ALS, and it is considered one of the most genetically and biologically driven illnesses. Thus far, the aims of psychological studies on ALS have focused on understanding patient - and, to a lesser extent, caregiver - QOL and psychological well-being. No previous study has investigated the influence of psychological factors on ALS. METHODS: A sample of 197 subjects with ALS were recruited and assessed online twice, with a duration of four months between the two assessments. Assessments included measurements of trait mindfulness, physical impairment, QOL, anxiety and depression. The influence of mindfulness as predictor of changes in physical impairments was evaluated with a mixed-effects model. RESULTS: Mindfulness positively influenced the change of physical symptoms. Subjects with higher mindfulness experienced a slower progression of the disease after four months. Moreover, mindfulness at first assessment predicted higher QOL and psychological well-being. CONCLUSIONS: The available data indicate that a psychological construct - mindfulness - can attenuate the progress of a disease that is believed to be almost solely biologically driven. The potential implications of these results extend well beyond ALS.

Overexpression of PLIN5 in skeletal muscle promotes oxidative gene expression and intramyocellular lipid content without compromising insulin sensitivity.

AIMS/HYPOTHESIS: While lipid deposition in the skeletal muscle is considered to be involved in obesity-associated insulin resistance, neutral intramyocellular lipid (IMCL) accumulation per se does not necessarily induce insulin resistance. We previously demonstrated that overexpression of the lipid droplet coat protein perilipin 2 augments intramyocellular lipid content while improving insulin sensitivity. Another member of the perilipin family, perilipin 5 (PLIN5), is predominantly expressed in oxidative tissues like the skeletal muscle. Here we investigated the effects of PLIN5 overexpression - in comparison with the effects of PLIN2 - on skeletal muscle lipid levels, gene expression profiles and insulin sensitivity. METHODS: Gene electroporation was used to overexpress PLIN5 in tibialis anterior muscle of rats fed a high fat diet. Eight days after electroporation, insulin-mediated glucose uptake in the skeletal muscle was measured by means of a hyperinsulinemic euglycemic clamp. Electron microscopy, fluorescence microscopy and lipid extractions were performed to investigate IMCL accumulation. Gene expression profiles were obtained using microarrays. RESULTS: TAG storage and lipid droplet size increased upon PLIN5 overexpression. Despite the higher IMCL content, insulin sensitivity was not impaired and DAG and acylcarnitine levels were unaffected. In contrast to the effects of PLIN2 overexpression, microarray data analysis revealed a gene expression profile favoring FA oxidation and improved mitochondrial function. CONCLUSIONS/INTERPRETATION: Both PLIN2 and PLIN5 increase neutral IMCL content without impeding insulin-mediated glucose uptake. As opposed to the effects of PLIN2 overexpression, overexpression of PLIN5 in the skeletal muscle promoted expression of a cluster of genes under control of PPARα and PGC1α involved in FA catabolism and mitochondrial oxidation.

Targeting of mitochondrial reactive oxygen species production does not avert lipid-induced insulin resistance in muscle tissue from mice.

AIMS/HYPOTHESIS: High-fat, high-sucrose diet (HF)-induced reactive oxygen species (ROS) levels are implicated in skeletal muscle insulin resistance and mitochondrial dysfunction. Here we investigated whether mitochondrial ROS sequestering can circumvent HF-induced oxidative stress; we also determined the impact of any reduced oxidative stress on muscle insulin sensitivity and mitochondrial function. METHODS: The Skulachev ion (plastoquinonyl decyltriphenylphosphonium) (SkQ), a mitochondria-specific antioxidant, was used to target ROS production in C2C12 muscle cells as well as in HF-fed (16 weeks old) male C57Bl/6 mice, compared with mice on low-fat chow diet (LF) or HF alone. Oxidative stress was measured as protein carbonylation levels. Glucose tolerance tests, glucose uptake assays and insulin-stimulated signalling were determined to assess muscle insulin sensitivity. Mitochondrial function was determined by high-resolution respirometry. RESULTS: SkQ treatment reduced oxidative stress in muscle cells (-23% p < 0.05), but did not improve insulin sensitivity and glucose uptake under insulin-resistant conditions. In HF mice, oxidative stress was elevated (56% vs LF p < 0.05), an effect completely blunted by SkQ. However, HF and HF+SkQ mice displayed impaired glucose tolerance (AUC HF up 33%, p < 0.001; HF+SkQ up 22%; p < 0.01 vs LF) and disrupted skeletal muscle insulin signalling. ROS sequestering did not improve mitochondrial function. CONCLUSIONS/INTERPRETATION: SkQ treatment reduced muscle mitochondrial ROS production and prevented HF-induced oxidative stress. Nonetheless, whole-body glucose tolerance, insulin-stimulated glucose uptake, muscle insulin signalling and mitochondrial function were not improved. These results suggest that HF-induced oxidative stress is not a prerequisite for the development of muscle insulin resistance.

Quantification of vitamin B6 vitamers in human cerebrospinal fluid by ultra performance liquid chromatography-tandem mass spectrometry.

Since vitamin B6 is essential for normal functioning of the central nervous system, there is growing need for sensitive analysis of B6 vitamers in cerebrospinal fluid (CSF). This manuscript describes the development and validation of a rapid, sensitive and accurate method for quantification of the vitamin B6 vitamers pyridoxal (PL), pyridoxamine (PM), pyridoxine (PN), pyridoxic acid (PA), pyridoxal 5'-phosphate (PLP), pyridoxamine 5'-phosphate (PMP) and pyridoxine 5'-phosphate (PNP) in human CSF. The method is based on ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) with a simple sample preparation procedure of protein precipitation using 50 g L(-1) trichloroacetic acid containing stable isotope labeled internal standards: PL-D(3) for PL and PM, PN-(13)C(4) for PN, PA-D(2) for PA and PLP-D(3) for the phosphorylated vitamers. B6 vitamers were separated (Acquity HSS-T3 UPLC column) with a buffer containing acetic acid, heptafluorobutyric acid and acetonitrile. Positive electrospray ionization was used to monitor transitions m/z 168.1→150.1 (PL), 169.1→134.1 (PM), 170.1→134.1 (PN), 184.1→148.1 (PA), 248.1→150.1 (PLP), 249.1→232.1 (PMP) and 250.1→134.1 (PNP). The method was validated at three concentration levels for each B6 vitamer in CSF. Recoveries of the internal standards were between 93% and 96%. Intra- and inter-assay variations were below 20%. Accuracy tests showed deviations from 3% (PN) to 39% (PMP). Limits of quantification were in the range of 0.03-5.37 nM. Poor results were obtained for quantification of PNP. The method was applied to CSF samples of 20 subjects and two patients on pyridoxine supplementation. Using minimal CSF volumes this method is suitable for implementation in a routine diagnostic setting.

Interproximal access efficacy of three manual toothbrushes with extended, x-angled or flat multitufted bristles.

PURPOSE: This laboratory research study was conducted to evaluate three manual toothbrushes for their ability to remove artificial plaque from interproximal sites. MATERIALS AND METHODS: Interproximal access efficacy (IAE) was evaluated using a pressure-sensitive artificial plaque substrate placed around simulated anterior and posterior teeth with horizontal and vertical brushing motions. Efficacy was determined as the maximum width of artificial plaque removed from around the teeth. Testing was conducted on three manual toothbrushes with different bristle configurations coded as: Extended [Aquafresh Between Teeth (also marketed as Dr. Best Zwischenzahn)], X-angled (Oral-B CrossAction) and Flat multitufted (Oral-B Indicator). Twenty-four tests on each toothbrush design were conducted, and the results were statistically analysed using two-sample t-tests, assuming unequal variances. RESULTS: The individual mean IAE values on anterior and posterior tooth shapes with vertical and horizontal brushing were significantly (P < 0.001) higher for the toothbrush with extended bristles (Aquafresh Between Teeth) than for the other two toothbrush designs tested. When the data were combined to give an overall average, the IAE for the toothbrush with extended bristles (Aquafresh Between Teeth) was significantly (P < 0.001) higher than the IAE value for the toothbrushes containing x-angled (Oral-B CrossAction) or flat multitufted bristles (Oral-B Indicator). CONCLUSION: Based on the demonstrated predictability of the IAE assay for clinical interproximal plaque removal, the manual toothbrush with extended bristles should be an effective brush for cleansing the dental interproximal sites.

The effect of brushing time and dentifrice quantity on fluoride delivery in vivo and enamel surface microhardness in situ.

While the clinical anticaries efficacy of fluoride toothpaste is now without question, our understanding of the relation of fluoride efficacy to brushing time and dentifrice quantity is limited. The aim of this in situ study was to determine how differences in brushing time and dentifrice quantity influence (i) fluoride distribution immediately after brushing, (ii) clearance of fluoride in saliva, (iii) enamel fluoride uptake (EFU) and (iv) enamel strengthening, via the increase in surface microhardness. The study compared brushing times of 30, 45, 60, 120 and 180 s with 1.5 g of dentifrice containing 1,100 microg/g fluoride as sodium fluoride. In addition, 60 s of brushing with 0.5 g dentifrice was evaluated. A longer brushing time progressively reduced retention of dentifrice in the brush, thereby increasing the amount delivered into the mouth. A longer brushing time also increased fluoride concentrations in saliva for at least 2 h after the conclusion of brushing, showing that increased contact time promoted fluoride retention in the oral cavity. There was a statistically significant positive linear relationship between brushing time and both enamel strengthening and EFU. Compared to 0.5 g dentifrice, brushing with 1.5 g dentifrice more than doubled the fluoride recovered in saliva after brushing and increased EFU. In conclusion, the results of this preliminary, short-term usage study suggest for the first time that both brushing time and dentifrice quantity may be important determinants both of fluoride retention in the oral cavity and consequent enamel remineralization.

A comparison of two chlorhexidine gel brushing regimens and a conventional toothpaste brushing regimen for the development of tooth staining over a 6-week period.

AIMS: A single-centre, randomized single-blind parallel study was undertaken to compare staining seen with three brushing regimens and to determine subject perception of side effects such as staining and effects on taste. METHODS: This 6-week parallel study used 157 volunteers who were randomized into one of three treatment groups: (i) brushing in the morning and evening with a normal dose of a 1% chlorhexidine gel, (ii) brushing with a low dose of chlorhexidine gel in the evening and a whitening dentifrice in the morning, and (iii) brushing with a standard fluoride paste in the morning and evening. Following home usage of their allocated products, the study volunteers returned after 3 and 6 weeks to record the amount of stain present. After the 6-week period, subject perception of taste and stain acceptability was determined using a questionnaire. RESULTS: After 6 weeks of use of the low-dose chlorhexidine gel and whitening dentifrice, significantly more stain was seen compared with the use of a standard dentifrice (P<0.0001). Similarly, significantly more stain was seen with use of the normal-dose chlorhexidine gel compared with the low-dose gel and whitening dentifrice (P=0.0007). Approximately 30% of individuals on the low-dose chlorhexidine gel regimen found the amount of stain unacceptable and 10% noted an effect on their taste perception. CONCLUSIONS: The use of low dose of chlorhexidine gel at night and a whitening paste in the morning produced a significant amount of stain that 30% of subjects considered unacceptable.

Spatial restriction of spontaneous activity towards the rostral primary initiating zone during development of the embryonic mouse hindbrain.

In the developing embryonic mouse hindbrain, we have previously shown that synchronized spontaneous activity is driven by midline serotonergic neurons at E11.5. This is mediated, at least in part, by the 5-HT2A receptor, which is expressed laterally in the hindbrain. Activity at E11.5 is widespread within the hindbrain tissue, propagating from the midline to more lateral regions. Using rapid acquisition of [Ca2+]i events along the midline, we now show that the rostral midline, primarily in the region of former rhombomere r2, is the primary initiating zone for this activity. We propose that at E11.5, the combined events along the rostral-caudal axis in combination with events propagating along the medial-lateral axis could assign positional information to developing neurons within the hindbrain. With further development, to E13.5, both the lateral and caudal dimensions of spontaneous activity retract to the rostral midline, occupying an area only 14% of that exhibited at E11.5. We also show that increased levels of [K+]o (to 8 mM) at E13.5 are able to increase the spread of spontaneous activity laterally and rostro-caudally. This suggests that spontaneous activity in the hindbrain depends in a dynamic way on the dominant initiating zone of the rostral midline, and that this relationship changes over development.

Primary role of the serotonergic midline system in synchronized spontaneous activity during development of the embryonic mouse hindbrain.

In the developing embryonic mouse hindbrain, we have shown that previously widespread synchronized spontaneous activity at E11.5 retracts to the initiating zone of the rostral hindbrain by E13.5, and ceases completely by E14.5. We now confirm that at E11.5 and E13.5, the primary driver of spontaneous activity is serotonergic input, while other transmitters (GABA, glutamate, NE, and ATP) have only modulatory roles. Using immunocytochemistry, we also show that at E13.5, 5-HT-positive neurons in the midline extend over a larger rostro-caudal distance than at E11.5, and that in the presumptive initiating zone, cell bodies occupy a band that extends 200 microm laterally on each side of the midline, with extensive axonal processes. The 5-HT2A receptor retains expression in lateral tissue over this developmental time. We find that in addition to being sensitive to 5-HT receptor antagonists, spontaneous activity is also abolished by blockers of gap junctions, and is increased in frequency and lateral spread by application of ammonium, presumably via increased intracellular pH augmenting gap junction conductance. Thus, 5-HT neurons of the midline remain the primary drivers of spontaneous activity at several stages of development in the hindbrain, relying in part on gap junctional communication during initiation of activity.

Clinical study to compare the effectiveness of a test whitening toothpaste with a commercial whitening toothpaste at inhibiting dental stain.

AIMS: A single centre, randomised single-blind, three-way crossover study was performed, to compare the effect of an experimental test toothpaste with a commercially available whitening toothpaste and water control at inhibiting extrinsic stain promoted by repeated chlorhexidine/tea rinses. METHODS: This study used 23 subjects. During the week before the study the subjects received a prophylaxis to remove all staining, plaque and calculus deposits. On the Monday of the following week subjects returned to the clinic to receive their rinses and to check their dentition was stain free. Under direct supervision at both 09:00 and 13:00 hours they rinsed with either a toothpaste slurry or water control that was repeated daily up to and including the following Thursday. Additionally from the Monday to the Thursday each subject rinsed with a 0.2% chlorhexidine mouthrinse, immediately followed by a rinse with a warm black tea solution. This cycle was repeated hourly eight times throughout the day and on the following days until the Friday. Throughout this period volunteers omitted all other forms of oral hygiene except rinsing with the chlorhexidine mouthwash. On the Friday the level of stain on the teeth and dorsum of tongue was assessed using the Lobene stain index for both stain area and intensity. At the end of each trial period each subject received a thorough prophylaxis to remove all plaque, calculus and staining before starting the second and third period of the study. RESULTS: As expected appreciable amounts of extrinsic stain accumulated on the teeth over each study period. The amount of stain following use of the toothpastes and water control was least with the experimental toothpaste, followed by water control and lastly the commercial whitening paste. For all sites combined there was evidence that the experimental paste was significantly superior to both the commercial paste and water control at reducing stain area (p<0.001), a product of stain area and intensity (p<0.001 and 0.05, respectively) but not stain intensity (p>0.05). CONCLUSIONS: In this stain-prevention model the use of an experimental paste showed a significant reduction in stain accumulation on the teeth compared with a (placebo) negative water control and a commercially available whitening paste. As such the experimental paste would be expected to be of benefit in controlling extrinsic dental staining.

Development of synchronized activity of cranial motor neurons in the segmented embryonic mouse hindbrain.

Spontaneous electrical activity synchronized among groups of related neurons is a widespread and important feature of central nervous system development. Among the many places from which spontaneous rhythmic activity has been recorded early in development are the cranial motor nerve roots that exit the hindbrain, the motor neuron pool that, at birth, will control the rhythmic motor patterns of swallow, feeding and the oral components of respiratory behaviour. Understanding the mechanism and significance of this hindbrain activity, however, has been hampered by the difficulty of identifying and recording from individual hindbrain motor neurons in living tissue. We have used retrograde labelling to identify living cranial branchiomeric motor neurons in the hindbrain, and [Ca2+]i imaging of such labelled cells to measure spontaneous activity simultaneously in groups of motor neuron somata. We find that branchiomeric motor neurons of the trigeminal and facial nerves generate spontaneous [Ca2+]i transients throughout the developmental period E9.5 to E11.5. During this two-day period the activity changes from low-frequency, long-duration events that are tetrodotoxin insensitive and poorly coordinated among cells, to high-frequency short-duration events that are tetrodotoxin sensitive and tightly coordinated throughout the motor neuron population. This early synchronization may be crucial for correct neuron-target development.

Unexpected rearrangement and expression of the immunoglobulin lambda1 locus in scid mice.

In severe combined immunodeficient (scid) mice, V(D)J recombination is severely impaired due to a recessive mutation (scid). Thus, we were surprised to find in this study that Vlambda1-Jlambda1 rearrangement is routinely detectable in scid fetal liver, adult bone marrow, and spleen in the apparent absence of completed VH-DJH and Vkappa-Jkappa rearrangements. Particularly surprising, we found the level of Vlambda1-Jlambda1 rearrangement in scid fetal liver to be comparable to that in fetal liver of wild-type mice. The majority of scid Vlambda1-Jlambda1 rearrangements contained abnormal deletions at the VJ junction, consistent with the known effect of scid. However, approximately 15% of Vlambda1-Jlambda1 rearrangements lacked abnormal deletions. Productive lambda1 transcripts resulting from in-frame rearrangements were readily detectable in scid adult bone marrow and spleen, consistent with our ability to detect lambda1-expressing cells by flow cytometry in the spleens of bcl-2-transgenic scid mice. Strikingly, lambda1 transcripts from individual scid mice often showed VJ junctional sequences with the same recurring palindromic (P) additions of three, four, or five nucleotides. To account for these findings, we suggest that (a) nonhomologous end joining of Vlambda1 and Jlambda1 coding ends in fetal B lineage cells may not be (severely) impaired by scid; (b) recurring P additions in scid lambda1 transcripts may reflect certain molecular constraints imposed by scid on the resolution of Vlambda1 and Jlambda1 hairpin coding ends; and (c), scid lymphocytes with productively rearranged Vlambda1 and Jlambda1 elements may differentiate into recombinase-inactive cells and emigrate from bone marrow to spleen.