Leukocytoclastic vasculitis in children: clinical characteristics, subtypes, causes and direct immunofluorescence findings of 56 biopsy-confirmed cases.

BACKGROUND: Leukocytoclastic vasculitis (LCV) in children is a complex group of conditions. OBJECTIVES: This study presents the demographics, clinical features, direct immunofluorescence (DIF) results and suspected aetiologies of 56 biopsy-confirmed cases of leukocytoclastic vasculitis in children. METHODS: Retrospective review of 56 children seen at Mayo Clinic in Rochester, Minnesota, from 1993 to 2013 with clinical features and cutaneous biopsy consistent with LCV. RESULTS: Twenty-seven (48%) cases were found to be due to IgA vasculitis (Henoch-Schonlein purpura). The remaining cases were found to be due to cutaneous small-vessel vasculitis (n = 19, 34%), urticarial vasculitis (n = 5, 9%), ANCA-associated vasculitis (n = 4, 7%) and acute haemorrhagic oedema of infancy (n = 1, 2%). IgA vasculitis was found to be associated with abdominal pain (P = 0.008), whereas the non-IgA vasculitis group was associated with headache (P = 0.052). Children with IgA vasculitis had palpable purpura (P = <0.001), petechia (P = 0.057), vesicles (P = 0.009) and involvement of the buttock (P = 0.004) more frequently than the non-IgA vasculitis group. On DIF, perivascular IgA was positive in IgA vasculitis compared to non-IgA vasculitis cases (P = <0.001), the other conjugates were similar between the two groups. CONCLUSION: The most common subtype of biopsy-confirmed LCV in children is IgA vasculitis. Clinical features, exam characteristics and DIF results can be helpful in determining the subtype of cutaneous vasculitis in children.

An improved strip FRAP method for estimating diffusion coefficients: correcting for the degree of photobleaching.

Fluorescence recovery after photobleaching is a widely established method for the estimation of diffusion coefficients, strip bleaching with an associated recovery curve analysis being one of the simplest techniques. However, its implementation requires near 100% bleaching in the region of interest with negligible fluorescence loss outside, both constraints being hard to achieve concomitantly for fast diffusing molecules. We demonstrate that when these requirements are not met there is an error in the estimation of the diffusion coefficient D, either an under- or overestimation depending on which assumption is violated the most. We propose a simple modification to the recovery curve analysis incorporating the concept of the relative bleached mass m giving a revised recovery time parametrization tau=m(2)w(2)/4piD for a strip of width w. This modified model removes the requirement of 100% bleaching in the region of interest and allows for limited diffusion of the fluorophore during bleaching. We validate our method by estimating the (volume) diffusion coefficient of FITC-labelled IgG in 60% glycerol solution, D= 4.09 +/- 0.21 microm(2) s(-1), and the (surface) diffusion coefficient of a green-fluorescent protein-tagged class I MHC protein expressed at the surface of a human B cell line, D= 0.32 +/- 0.03 microm(2) s(-1) for a population of cells.

The effect of a domiciliary denture service on oral health related quality of life: a randomised controlled trial.

OBJECTIVES: To assess the effectiveness of a domiciliary denture service on the oral health related quality of life (OHQoL) of older patients requiring complete dentures. DESIGN: Community based single-blind randomised controlled trial. SUBJECTS AND METHODS: 133 edentate adults aged 65 years and over referred to a community dental service for domiciliary care were assigned to study and control groups using block randomisation. Treatment to provide the study group with complete dentures commenced immediately. Treatment for the control group was deferred to the normal waiting list but in the interim participants received three home visits from the dental team. Follow up data were collected three months after dentures had been fitted in the study group. OUTCOME MEASURES: Prevalence, extent of impacts and total scores using Oral Impacts on Daily Performance (OIDP). RESULTS: The study and control groups (n = 65 and 68 respectively) had similar OHQoL at baseline. Two and five participants were lost to the study and control groups respectively. In ANCOVA and intention to treat analysis, the presence of impact, number of impacts and total scores for OIDP at follow up were predicted by group allocation (b = 0.28, b = 0.30, and b = 0.32 respectively. All p <0.001). In all cases the study group showed significantly improved OHQoL compared to the control group. CONCLUSION: A domiciliary denture service improved oral health related quality of life of housebound edentulous older people.

Multifocal multiphoton excitation and time correlated single photon counting detection for 3-D fluorescence lifetime imaging.

We report a multifocal multiphoton time-correlated single photon counting (TCSPC) fluorescence lifetime imaging (FLIM) microscope system that uses a 16 channel multi-anode PMT detector. Multiphoton excitation minimizes out-of-focus photobleaching, multifocal excitation reduces non-linear in-plane photobleaching effects and TCSPC electronics provide photon-efficient detection of the fluorescence decay profile. TCSPC detection is less prone to bleaching- and movement-induced artefacts compared to wide-field time-gated or frequency-domain FLIM. This microscope is therefore capable of acquiring 3-D FLIM images at significantly increased speeds compared to single beam multiphoton microscopy and we demonstrate this with live cells expressing a GFP tagged protein. We also apply this system to time-lapse FLIM of NAD(P)H autofluorescence in single live cells and report measurements on the change in the fluorescence decay profile following the application of a known metabolic inhibitor.

A study to compare the oral health impact profile and satisfaction before and after having replacement complete dentures constructed by either the copy or the conventional technique.

AIMS: To assess the oral health impact profile (OHIP) on edentulous subjects who needed to have their dentures replaced either by a copy technique or a conventional technique, and to determine whether any change in the subjects' assessment of their original and replacement dentures impacted on oral health related quality of life parameters. BACKGROUND: The OHIP is an instrument used to measure subjects' perceptions of the social impact of oral disorders on their well being. Changes in the OHIP may occur when subjects need to have their complete dentures replaced. Furthermore, it is possible that the method by which the dentures are constructed may impact on this. METHODS: A total of 65 edentulous subjects were studied. Thirty-three subjects had their dentures constructed by a copy technique and 32 by a conventional technique. Subjects completed the OHIP-14 questionnaires before and after being provided with a set of replacement complete dentures. They also assessed specific features of the upper and lower dentures. Responses were recorded on a Likert scale. RESULTS: For many subjects, the responses in the before treatment questionnaires were at the lower end of the Likert scale, indicating that there were no major impacts on oral health related quality of life parameters. There were no major differences between the copy denture subjects and the conventional denture subjects in relation to the change in OHIP scores before and after treatment. Generally subjects expressed improved satisfaction with the new lower denture. However, for the copy denture group there were significant improvements for all seven assessments compared with only five out of seven assessments for subjects in the conventional group. CONCLUSION: For these groups of edentulous subjects, although they may need dentures to be replaced after a period of wear, this does not necessarily have significant impacts on oral health related quality of life parameters. It seems likely that this is the main reason why the provision of new dentures by either a copying or conventional technique did not result in major changes to the OHIP.

Differential effects of estrogen on hippocampal- and striatal-dependent learning.

Estrogen's role in learning and memory may be to predispose animals to use specific cognitive strategies (Korol & Kolo, 2002). Specifically, estrogen may facilitate hippocampal-dependent learning, while at the same time attenuate striatal-dependent learning. As a stringent test of this hypothesis, place or response learning on an eight-arm radial maze was compared between ovariectomized (OVX) female Long-Evans rats and rats with chronic estrogen replacement (OVX+E; 5mg 17-beta estradiol 60-day release tablet). Reference and working memory errors were monitored separately for both place and response learning tasks. OVX+E rats learned the place task significantly faster than the response task, and faster than OVX rats. OVX rats required fewer days to reach criterion on the response task than OVX+E rats. Estrogen selectively enhanced reference memory performance, but only during place learning. The specific pattern of estrogen effects on learning suggests that future studies include verification of cognitive strategies used by animals.

Imaging fluorescence lifetime heterogeneity applied to GFP-tagged MHC protein at an immunological synapse.

Fluorescence imaging of green fluorescent protein (GFP) may be used to locate proteins in live cells and fluorescence lifetime imaging (FLIM) may be employed to probe the local microenvironment of proteins. Here we apply FLIM to GFP-tagged proteins at the cell surface and at an inhibitory natural killer (NK) cell immunological synapse (IS). We present a novel quantitative analysis of fluorescence lifetime images that we believe is useful to determine whether apparent FLIM heterogeneity is statistically significant. We observe that, although the variation of observed fluorescence lifetime of GFP-tagged proteins at the cell surface is close to the expected statistical range, the lifetime of GFP-tagged proteins in cells is shorter than recombinant GFP in solution. Furthermore the lifetime of GFP-tagged major histocompatibility complex class I protein is shortened at the inhibitory NK cell IS compared with the unconjugated membrane. Following our previous work demonstrating the ability of FLIM to report the local refractive index of GFP in solution, we speculate that these lifetime variations may indicate local refractive index changes. This application of our method for detecting small but significant differences in fluorescence lifetimes shows how FLIM could be broadly useful in imaging discrete membrane environments for a given protein.

Can membrane nanotubes facilitate communication between immune cells?

Recent observations have revealed that intercellular connections can be formed through membrane nanotubes. These delicate structures could facilitate transport of organelles and membrane proteins between cells. The sharing of cell surface and cytoplasmic components between cells could be commonplace in biology, but an important physiological role for membrane nanotubes between immune cells is difficult to test with current technology.

Successful oesophageal pH monitoring with a catheter-free system.

BACKGROUND: Traditional catheter-based oesophageal pH testing is limited by patient discomfort and the tendency for patients to alter their diet and activities during the study. A catheter-free pH monitoring system (Bravo) designed to avoid these problems has recently become available, but the advantages and limitations of this device have not been fully explored. AIM: To report our initial experience with this new technology. METHODS: The records of consecutive patients undergoing Bravo pH monitoring were reviewed. The squamo-columnar junction was localized endoscopically and the pH capsule was placed 6 cm above this junction. All patients were re-endoscoped immediately following placement to document mucosal attachment. Patients were monitored for 24-48 h and then returned the radiotelemetry recording device. Data were subsequently downloaded to a personal computer. RESULTS: Sixty studies were performed over an 11-month period. In seven of the 60 (12%), the probe did not attach properly, but in six of these a replacement probe was prepared and deployed without difficulty. In one case, the probe could not be attached after two attempts and the procedure was abandoned. During one procedure, the probe was attached to the mucosa at a point 9 cm from the squamo-columnar junction, but a positive test result was obtained. In two cases, the data were not initially retrievable from the recorder, but in one case the manufacturer was able to retrieve the data overnight. Finally, two patients were away from the data recorder for extended periods, resulting in a loss of data, in two cases, but there was sufficient information for interpretation in both studies. Therefore, adequate diagnostic data were obtained in 58 of the 60 (97%) studies. CONCLUSIONS: Catheter-free pH testing is a major advance in patient convenience and comfort. The technical difficulties associated with this new technology are minimal and appear to be no more frequent than those seen with catheter-based systems.

Signaling at the inhibitory natural killer cell immune synapse regulates lipid raft polarization but not class I MHC clustering.

Natural killer (NK) cell cytotoxicity is determined by a balance of positive and negative signals. Negative signals are transmitted by NK inhibitory receptors (killer immunoglobulin-like receptors, KIR) at the site of membrane apposition between an NK cell and a target cell, where inhibitory receptors become clustered with class I MHC ligands in an organized structure known as an inhibitory NK immune synapse. Immune synapse formation in NK cells is poorly understood. Because signaling by NK inhibitory receptors could be involved in this process, the human NK tumor line YTS was transfected with signal-competent and signal-incompetent KIR2DL1. The latter were generated by truncating the KIR2DL1 cytoplasmic tail or by introducing mutations in the immunoreceptor tyrosine-based inhibition motifs. The KIR2DL1 mutants retained their ability to cluster class I MHC ligands on NK cell interaction with appropriate target cells. Therefore, receptor-ligand clustering at the inhibitory NK immune synapse occurs independently of KIR2DL1 signal transduction. However, parallel examination of NK cell membrane lipid rafts revealed that KIR2DL1 signaling is critical for blocking lipid raft polarization and NK cell cytotoxicity. Moreover, raft polarization was inhibited by reagents that disrupt microtubules and actin filaments, whereas synapse formation was not. Thus, NK lipid raft polarization and inhibitory NK immune synapse formation occur by fundamentally distinct mechanisms.

Intercellular transfer and supramolecular organization of human leukocyte antigen C at inhibitory natural killer cell immune synapses.

After accumulation of target cell human leukocyte antigen (HLA)-C at inhibitory natural killer (NK) cell immune synapses, some HLA-C transfers from target cells to NK cell plasma membranes and cytoplasm. This unexpected intercellular transfer of HLA-C is dependent on NK receptor recognition, since HLA-Cw6 or -Cw4 but not -Cw3 transfer to an NK transfectant expressing killer Ig-like receptor (KIR)2DL1. Strikingly, live-cell time-lapse laser scanning confocal microscopy shows vesicles containing target cell green fluorescent protein-tagged HLA-C migrating away from immune synapses into NK cells. Unlike clustering of HLA-C at the immune synapse, intercellular transfer of HLA-C is dependent on NK cell ATP, but not target cell ATP. However, the intercellular transfer of HLA-C is not dependent on active polymerization of the actin cytoskeleton. In addition, different arrangements of HLA-C are seen at inhibitory NK immune synapses, and these alter as NK synapses mature, but in a fashion distinct from that seen upon T cell activation.

Recognition of haemagglutinins on virus-infected cells by NKp46 activates lysis by human NK cells.

Natural killer (NK) cells destroy virus-infected and tumour cells, apparently without the need for previous antigen stimulation. In part, target cells are recognized by their diminished expression of major histocompatibility complex (MHC) class I molecules, which normally interact with inhibitory receptors on the NK cell surface. NK cells also express triggering receptors that are specific for non-MHC ligands; but the nature of the ligands recognized on target cells is undefined. NKp46 is thought to be the main activating receptor for human NK cells. Here we show that a soluble NKp46-immunoglobulin fusion protein binds to both the haemagglutinin of influenza virus and the haemagglutinin-neuraminidase of parainfluenza virus. In a substantial subset of NK cells, recognition by NKp46 is required to lyse cells expressing the corresponding viral glycoproteins. The binding requires the sialylation of NKp46 oligosaccharides, which is consistent with the known sialic binding capacity of the viral glycoproteins. These findings indicate how NKp46-expressing NK cells may recognize target cells infected by influenza or parainfluenza without the decreased expression of target-cell MHC class I protein.

The emotional effects of tooth loss in a group of partially dentate people: a quantitative study.

This study investigated the reactions to tooth loss in a partially dentate group of 100 people using a questionnaire-based method. Partially dentate people who experienced difficulties in accepting their tooth loss were more likely to feel less confident, restrict food choice, enjoy food less, avoid laughing in public and avoid forming close relationships than those people who had no difficulties accepting tooth loss. Also, they were more likely to feel that they had not been adequately prepared for the effects that tooth loss had on their confidence, daily living activities and appearance.

The emotional effects of tooth loss in partially dentate people attending prosthodontic clinics in dental schools in England, Scotland and Hong Kong: a preliminary investigation.

AIM: To compare the emotional effects of tooth loss in three partially dentate populations. DESIGN: A questionnaire survey. MATERIALS AND METHODS: A questionnaire was completed by 150 partially dentate subjects undergoing routine prosthodontic care at Guy's, King's and St Thomas's Dental Institute, London; the Dental School, Dundee, Scotland; and the Faculty of Dentistry, University of Hong Kong. Data were analysed using the Chi-square test. RESULTS: Forty nine per cent of all participants reported difficulties in accepting the loss of some of their teeth. People from Dundee were less likely to have difficulties accepting tooth loss (P = 0.001). People from London took longer to come to terms with their tooth loss and were more likely to feel less confident (P < 0.001). Fifty five per cent of all participants restricted their choice of foods and 54 per cent had not enjoyed their food as much as before. Fewer people in Dundee restricted their choice of food (P < 0.001) and were more likely to enjoy their food (P = 0.009). People in Hong Kong were most likely to restrict their choice of food (P = 0.006). Thirty five percent of all subjects felt unprepared for the effects that tooth loss had upon them. People in Hong Kong were more prepared for tooth loss than those in Dundee and London (P = 0.003). In addition, they were less concerned about leaving their dentures out overnight (P = 0.024). CONCLUSIONS: The emotional effects of tooth loss were significant in all groups. People from London took longer to come to terms with their tooth loss.

Attributions of responsibility for children's mental health problems: parents and professionals at odds.

Surveys of 102 mothers of inner-city youths with mental health problems and their clinicians examined discrepancies in mothers' and professionals' causal and solution attributions for the children's problems. Greater causal responsibility was attributed to mothers by professionals than by mothers, while they agreed on the children's responsibility. They disagreed about their respective solution responsibilities, though agreeing that causally responsible children should help with solutions. Mothers considered many more community resources for solutions than did professionals. Implications for improvement of services to urban children are discussed.

A transcultural perspective on the emotional effect of tooth loss in complete denture wearers.

PURPOSE: The purpose of this study was to compare the emotional effects of tooth loss in three edentulous populations. MATERIALS AND METHODS: A questionnaire study involved 142 edentulous subjects undergoing routine prosthodontic care at Guy's, King's and St Thomas's Dental Institute, London; the Dental School, Dundee, Scotland; and the Faculty of Dentistry, University of Hong Kong. Data were analyzed using the chi-squared test. RESULTS: Difficulty in accepting tooth loss was a relatively common experience (44%) in all groups, with almost half feeling that their confidence had been affected. The majority (66%) felt that their choice of food was restricted and that the overall eating experience was less enjoyable, particularly the Hong Kong group. A significant proportion of the participants were concerned about their appearance without dentures, although the trend was less marked in Hong Kong. Forty-three percent felt that they were not adequately prepared for tooth loss, although the Hong Kong group was least concerned. CONCLUSION: In general, the emotional effect of tooth loss was significant in all groups. The restrictions on daily activities were generally greater in the Hong Kong group. However, this group was much less inhibited by denture wearing. The differences observed in the Hong Kong Chinese are most likely due to different cultural values and expectations associated with these aspects of daily living.

Assembly and dissociation of human leukocyte antigen (HLA)-A2 studied by real-time fluorescence resonance energy transfer.

Class I major histocompatibility complex (MHC) heterodimer, composed of human leukocyte antigen (HLA)-A2 heavy chain and human beta(2)-microglobulin (beta(2)m), was produced by denaturation and gel filtration of the recombinant water-soluble HLA-A2/beta(2)m/peptide ternary complex in 8 M urea Tris-HCl buffer, followed by refolding of the separated chains without peptide. Peptide affinity and kinetics of the ternary complex formation and dissociation were investigated in real time by monitoring the fluorescence resonance energy transfer (FRET) from intrinsic HLA-A2 heavy-chain tryptophans to a dansyl fluorophore conjugated to the bound peptide. Peptide binding to the heterodimer was a second order process with rate constants linearly dependent upon temperature in Arrhenius coordinates over 0-20 degrees C. The binding rate constant of pRT6C-dansyl [ILKEPC(dansyl)HGV] at 37 degrees C evaluated by extrapolation of the Arrhenius plot was (2.0 +/- 0.5) x 10(6) M(-1) s(-1). Association of the heavy chain with beta(2)m was a first order process, apparently controlled by a conformational transition in the heavy chain. One of these conformations bound to beta(2)m to form the heavy chain/beta(2)m heterodimer whereas the second conformer oligomerized. Peptide dissociation from the ternary complex was a first-order reaction over the temperature range 20-37 degrees C, suggesting that the ternary complex also exists in two conformations. Taken together, the present data suggest that association of beta(2)m changes the HLA-A2 heavy-chain conformation thereby promoting peptide binding. Peptide dissociation from the ternary complex induces dissociation of the heavy-chain/beta(2)m heterodimer thereby causing oligomerization of the heavy chain. The lability of the HLA-A2/beta(2)m heterodimer and the strong tendency of the "free" heavy chain to oligomerize may provide an efficient mechanism for control of antigen presentation under physiological conditions by reducing the direct loading of HLA with exogenous peptide at the cell surface.

The emotional effects of tooth loss: a preliminary quantitative study.

AIM: To establish how widespread the emotional effects of tooth loss are. METHOD: A questionnaire, distributed to 100 edentulous people undergoing routine prosthetic care in the Department of Prosthetic Dentistry at Guy's, King's and St Thomas' Dental Institute (GKT), was used to explore the emotional effects of tooth loss. RESULTS: Ninety four people completed the questionnaire of whom 42 stated that they had experienced difficulties in accepting the loss of their teeth. In comparison with people who had no difficulties in accepting the situation, these people were: more likely to feel less confident about themselves; more likely to feel inhibited in carrying out everyday activities; and less able to accept the inevitable change in facial shape which occurs following the loss of teeth. Additionally, they took longer to come to terms with their tooth loss (All these differences were statistically significant). Just over three-quarters of the people who were unprepared for the loss of their teeth, felt that an explanation from the dentist prior to dental extractions would have helped. CONCLUSION: The impact that tooth loss can have on people and their lives should not be underestimated. In this study it affected 45% of the participants.

Accurate placement of the esophageal pH electrode for 24-hour pH monitoring using a combined pH/manometry probe.

OBJECTIVE: Accurate placement of a pH electrode requires manometric localization of the lower esophageal sphincter (LES). Combined manometry/pH devices using water-perfused tubes attached to pH catheters and the use of an electronic "LES locator" have been reported. We investigated whether accurate placement of pH probes can be achieved using such a probe, and whether this may reduce the need for the performance of the usual stepwise pull-back manometry. METHODS: Thirty consecutive patients (15 men, 15 women; median age, 56 yr; interquartile range, 42-68 yr) referred for manometry and pH testing were included in the study. The localization of the LES was determined with standard esophageal manometry. After that, a second 3-mm pH electrode with an internal perfusion port was passed into the stomach. Using this catheter, a single stepwise pull-through manometry was performed and the LES position was noted. LES location, mean pressure, and length obtained with standard manometry were compared to data from the combined pH/manometry catheter. Additionally the time necessary to perform each of the procedures was noted and the patient's discomfort caused by the catheter was evaluated using a standardized questionnaire. RESULTS: The LES location with the pH/manometry probe was proximal to that with standard manometry in 19 patients (63%), the same in nine patients (30%), and distal in two patients (7%). The differences were <2 cm in 29 of 30 (97%) patients. The LES location with the pH/manometry probe required a median of 6.5 min (interquartile range: 3.5-8.5 min) versus a median of 21.5 min (interquartile range: 14.5-26.5 min) for standard manometry (p < 0.0001). In addition, LES evaluation using the combined pH/manometry probe provided accurate data on the resting pressure, as well as overall and intraabdominal length of the LES. All patients tolerated the combination probe better than the standard manometry probe (p < 0.001). CONCLUSIONS: Placement of the esophageal electrode for 24-h esophageal pH monitoring using a combined pH/manometry probe is accurate. The technique is simple, time-saving, and convenient for the patients. Because it is possible to accurately evaluate the LES using this technique, it may even replace conventional manometry before pH probe placement.

The maintenance requirements of mandibular overdentures stabilized by Astra Tech implants using three different attachment mechanisms--balls, magnets, and bars; 3-year results.

Thirty seven people were provided with mandibular overdentures stabilized by Astra Tech implants. Thirteen people were provided with ball attachments, 12 with magnet attachments and 12 with bar attachments. The patients were followed for 3 years and detailed records were kept of the extent of maintenance required after placement of the dentures. The bar attachment mechanism required 9 episodes of maintenance, compared to 38 for the ball attachment mechanism and 23 for the magnet attachment mechanism. There was no difference between the three groups for the amount of maintenance required by the overdentures. The design of the ball attachment changed during the study from a two piece to a one piece abutment. It is likely that had this "all in one" attachment been available from the beginning of the study, the amount of maintenance required by the ball attachment mechanism would have been considerably less.