A case of pilomyxoid astrocytoma presenting with CSF rhinorrhoea in a 15-year-old

We report a pilomyxoid astrocytoma (PMA) presenting with CSF rhinorrhoea in a 15-year-old. This uncommon, recently described entity typically presents in infancy with focal neurological or endocrine symptoms, has distinctive histologic features and displays a more aggressive behaviour than pilocytic astrocytoma (PA) with which it was previously classified.

Interindividual differences in the perception of dental stimulation and related brain activity

For identical diagnoses in the trigeminal innervation territory, individual differences have been clinically observed among the symptoms reported, such as dysesthesia and pain. Different subjective perceptions of unpleasantness and pain intensity may have different cortical substrates. The aim of this study was to identify brain areas in which activation depends on the subjective perception (intensity and unpleasantness) of electric dental stimulation. Electrical stimuli of increasing intensity were applied to maxillary canines in 14 healthy volunteers. Ratings for stimulus intensity and unpleasantness perceived across the stimulation session were reported postscan on 11-point numerical scales. The rating values were then included as covariates in the functional magnetic resonance imaging (fMRI) group analysis. Interindividual differences of intensity ratings were reflected in differential activity of the following brain areas: superior parietal lobule, superior temporal gyrus/anterior insula, inferior and middle temporal gyrus, lingual gyrus, anterior cingulate, and caudate nucleus. Differences related to unpleasantness ratings were reflected in the lingual gyrus. In conclusion, differences of perceived intensity between individuals are reflected in the differential activity of a set of brain areas distinct from those regions, reflecting rating differences of unpleasantness.

Development of an in situ methodology for the clinical evaluation of dentine hypersensitivity occlusion ingredients

OBJECTIVE

The aim of these clinical studies was to evaluate an in situ dentine tubule occlusion model, and to determine the occluding effect from novel occluding agents on patent dentine tubules compared to a positive control (8% strontium acetate--Sensodyne Mint) and negative control (a non-occluding agent) after four days of brushing treatment.

METHODS

These two in situ clinical studies were of single-center, randomized, crossover, single-blind design. Healthy participants wore two lower intra-oral appliances retaining four dentine samples for four treatment days for each period of the study. Samples were power-brushed each day with the test product. Assessment utilized surface topological analysis with a replica-based methodology under scanning electron microscopy (SEM).

RESULTS

Both clinical trials demonstrated that the positive control (8% strontium acetate) occluded dentine tubules significantly better (p = 0.0007; p < 0.0009) than the negative controls in the two studies, respectively. The experimental occluding agents demonstrated varying degrees of success for occluding effect compared to the controls.

CONCLUSION

The methodology clearly demonstrates that this in situ clinical model can robustly and reproducibly detect the dentine tubular occlusive effects of positive and negative controls in the treatment of dentine hypersensitivity brushed on the dentine surface. Using this methodology, new occlusion agents for the relief of dentine hypersensitivity can be assessed for occlusive effects on dentine.

Histological observations of bovine tuberculosis in lung and lymph node tissues from British deer

Deer are recognized as hosts of Mycobacterium bovis and assessing the role of wild cervids in perpetuating tuberculosis among cattle has motivated extensive research on several continents. In this paper, the histopathology of lymph node and lung tuberculous granulomas in M. bovis positive British deer is presented. The overall aim was to seek further insights into the potential for onward transmission from infected deer to other species, including cattle. Samples were obtained from an extensive survey of wild mammals in South-West England and from statutory tuberculosis surveillance. M. bovis culture-positive samples were characterised microscopically as to their stage of lesion advancement, number of acid-fast bacilli and granuloma encapsulation. Seventy percent of the deer developed granulomas containing far greater numbers of M. bovis bacilli than typically reported in cattle. Red and fallow deer had the largest number of poorly encapsulated granulomas often containing many hundreds of bacilli. The results are consistent with infected wild British deer being a potential source of environmental contamination and onward transmission to other species. However, further work on levels of bacillary shedding is required before this can be confirmed.

Effect of massage of the hamstring muscles on selected electromyographic characteristics of biceps femoris during sub-maximal isometric contraction

The aim of this study was to investigate whether a single massage of the hamstring muscles would alter selected electromyographic characteristics of biceps femoris during a sub-maximal isometric contraction. Eleven healthy young males participated in this crossover study. They were randomly assigned to two groups, receiving either a 15-minute hamstring muscle massage or a 15-minute prone rest. One week later they returned to receive the alternate intervention. Immediately pre- and post-intervention, participants were instructed to contract their muscles just sufficiently to maintain right knee flexion (5 degrees from full extension) for 30 seconds. Simultaneous to this contraction, surface electromyography (EMG) was used to record the electrical activity of right biceps femoris. Electromyograms were analyzed by calculating the averaged/integrated EMG (aEMG) and median frequency (MF) for each of 14 one-second windows, sampled every two seconds throughout the 30-second contractions per participant. Mean values of aEMG and MF were calculated per participant (aEMGmean and MFmean), pre- and post-massage or rest intervention. Group means (n = 11) of aEMGmean and MFmean were then calculated and compared using a repeated measures analysis of variance (ANOVA) procedure (p < 0.05). Rates of change of aEMG and MF throughout each 30-second contraction were represented by their respective gradients as functions of time. These gradients were similarly compared pre- to post-intervention using repeated measures ANOVA (p < 0.05). For the young healthy males considered in this study, a single massage of the hamstring muscles had no statistically significant effects on selected electromyographic characteristics of biceps femoris during sub-maximal isometric contractions (p > 0.05).

Dentine hypersensitivity: is there both stimulus and placebo responses in clinical trials?

AIM

To determine whether application of a periodontal dressing stopped pain arising from dentine hypersensitivity, objectively assessed with evaporative and thermal stimuli and recorded with Visual Analogue Scale scoring (VAS).

MATERIALS AND METHODS

22 subjects completed the single-centre, subject-blind, stratified, randomized, split-mouth study, with a minimum of two sensitive teeth, in at least two different quadrants, displaying a response of >or=30 mm with VAS to evaporative stimulus. One tooth in two different quadrants was identified and randomized to test or control groups. A dressing was applied to all the sensitive teeth in the test quadrant, and either side of the chosen sensitive tooth on the control side. The test teeth were then stimulated for hypersensitivity using evaporative stimuli and then using thermal stimuli.

RESULTS

Analysis showed that dressing application produced significantly greater reduction in pain (P<0.0001) compared with no periodontal dressing. Single application of a dressing to sensitive dentine provided 95% pain relief associated with thermal stimulus and 85% pain relief associated with evaporative stimulus.

CONCLUSIONS

Application of the dressing to sensitive teeth, dramatically reduced the pain of dentine hypersensitivity following tooth stimulation. When assessing subjects' response to pain-evoking stimuli, perception of pain appears to be altered by sensory factors, prompting a heightened pain response.

Effect of massage of the hamstring muscle group on performance of the sit and reach test

OBJECTIVE

To investigate if a single massage of the hamstring muscle group would alter the performance of the sit and reach test.

METHODS

Before treatment, each of 11 male subjects performed the sit and reach test. The treatment consisted of either massage of the hamstring muscle group (both legs, total time about 15 minutes) or supine rest with no massage. Performance of the sit and reach test was repeated after treatment. Each subject returned the subsequent week to perform the tests again, receiving the alternative treatment relative to their initial visit. Mean percentage changes in sit and reach scores after treatment were calculated for the massage and no massage treatments, and analysed using Student's t tests.

RESULTS

Mean (SD) percentage changes in sit and reach scores after massage and no massage were small (6.0 (4.3)% and 4.6 (4.8)% respectively) and not significantly different for subjects with relatively high (15 cm and above) values before treatment. Mean percentage changes in sit and reach scores for subjects with relatively low values before treatment (below 15 cm) were large (18.2 (8.2)% and 15.5 (16.2)% respectively), but no significant differences were found between the massage and no massage groups.

CONCLUSIONS

A single massage of the hamstring muscle group was not associated with any significant increase in sit and reach performance immediately after treatment in physically active young men.

A new in vivo interdental sampling method comparing a daily flossing regime versus a manual brush control

OBJECTIVE

The impact of flossing the interdental space is typically assessed by visual methods of questionable reliability, such as clinician observations and evaluations for scoring of plaque on visual tooth surfaces. The objective of this study was to develop and validate a method to measure interproximal quantities of dental plaque, thereby permitting quantitative evaluations of between-teeth cleaning and biofilm removal.

METHODOLOGY

Laboratory studies were performed correlating the quantity of bacteria to the amount of measured protein in a sample using a standardized protein assay (Bio-Rad Protein Assay) and samples containing single bacterial species and saliva/bacterial pellets. Analysis of the plaque was standardized against a bovine serum albumin (BSA) control. Pilot studies helped develop a technique for hygienist-applied interproximal flossing, reducing contamination from saliva and other possible sources of indeterminate error. Repeated sampling experiments were carried out to optimize the technique needed to remove the majority of quantifiable plaque, the best choice of flossing material, and establish the technique for collection. A pilot clinical trial assessed the benefits of daily flossing in reducing measurable quantities of interproximal plaque using the developed method. Thirty-nine subjects had six interdental sites (distributed across all four quadrants, pre-molar and molar boundaries) sampled on either side, over a three-week treatment period, in two balanced and equally sized treatment groups, with twice-daily manual brushing with or without daily flossing.

RESULTS

Laboratory studies confirmed the accuracy of the protein detection kit in assaying bacterial plaque loads from single species or complex biofilms. In pilot developmental screens, single flossing sweeps with appropriate dental floss were sufficient to remove the majority of quantifiable biomass from interproximal sites. The clinical study demonstrated that after three weeks, interdental plaque in floss users was significantly reduced versus baseline scores. Non-floss users showed no significant reduction. In direct comparison, less interdental plaque was recovered from subjects who had followed a daily flossing regime compared to subjects who had used a manual toothbrush alone (p = 0.0866).

CONCLUSION

The sampling method quantified the cleaning effects of daily flossing on interproximal plaque levels. Daily flossing significantly reduced the amount of plaque found between the teeth compared to a manual brushing regimen alone. This new method should be useful in future studies on the evaluation of mechanical or chemical means of interproximal plaque control.

Cluster and regional influences on suicide in a Southwestern American Indian tribe

Suicide is the second leading cause of death among American Indian youth. Elevated rates of suicide in Indian communities have been attributed both to outbreaks and to regional trends. We assessed the contribution of these two factors for a single tribe, and attempted to define a profile of individuals at risk. Data came from the tribe's registry of suicide attempts and completions for 1990-1993 and analysis of death certificates for the period 1985-1996. Using combined tribal and death certificate data, the average annual (age-adjusted) rate of completed suicide among tribal members was 44.7/100,000 for 1990-1993. Within the 45 suicide deaths and serious attempts in this time period, we identified one grouping of seven cases taking place in a 40-day period. All seven involved hanging and youth (13-28 years old). Using death certificate data alone, the average annual rate of suicide death for non-natives in the surrounding county in the period 1985-1996 was 22.7/100,000. Age-adjusted to the county population, the tribal rate for the same period was not significantly different (24.6/100,000). Tribal and county suicide patterns differed by age distribution and method but not by gender. We concluded that both regional trends and clustering contribute to suicide in this community. Further prevention efforts may need to focus on both unique tribal characteristics and shared factors among non-native neighbors.

Radiation safety considerations for large, multi-user laboratories

Many research institutions are adding new laboratory space in the form of large, multi-user rooms with an open architecture. Unfortunately, many of the features that make such rooms attractive to researchers make them difficult to manage from a radiation safety perspective. In particular, coping with radiological incidents and enforcing radiation safety standards are difficult when several research teams share a common room. This paper discusses the problems noted in such laboratories at the University of Rochester and Yale University and describes the manner in which some of these problems have been addressed.

Signalling interactions during facial development

The development of the vertebrate face is a dynamic multi-step process which starts with the formation of neural crest cells in the developing brain and their subsequent migration to form, together with mesodermal cells, the facial primordia. Signalling interactions co-ordinate the outgrowth of the facial primordia from buds of undifferentiated mesenchyme into the intricate series of bones and cartilage structures that, together with muscle and other tissues, form the adult face. Some of the molecules that are thought to be involved have been identified through the use of mouse mutants, data from human craniofacial syndromes and by expression studies of signalling molecules during facial development. However, the way that these molecules control the epithelial-mesenchymal interactions which mediate facial outgrowth and morphogenesis is unclear. The role of neural crest cells in these processes has also not yet been well defined. In this review we discuss the complex interaction of all these processes during face development and describe the candidate signalling molecules and their possible target genes.

Developing mental health services for Native American children

Important cultural, linguistic, traditional, and spiritual differences among Native American reservations are likely to go unrecognized to the detriment of children in need of mental health intervention. The authors discuss the impact of these factors on the expressions of psychiatric distress of Native American children, their care-seeking behaviors, and the acceptability of the forms taken by mental health systems that serve them. They suggest new, innovative models of care that can be developed within the context of contemporary Native American culture. Although the roles envisioned for child psychiatrists include the provision of direct clinical service, the authors posit that a model in which child psychiatrists provide consultation and supervision to native outreach and other mental health workers is a more acceptable and potentially more effective use of scarce resources.

Selective modulation of protein kinase C-theta during T-cell activation

Every cell contains many families of protein kinases, and may express several structurally related yet genetically distinct kinases of each family. The activity of the serine/threonine protein kinase C (PKC) enzymes has long been implicated in T-cell activation, but it is not known which members of the PKC family regulate the T-cell response to foreign antigens. The activation of T cells by antigen-presenting cells (APCs) is spatially restricted to their site of contact, where receptors on the T cells engage their counter-receptors on the APCs. We used this localized engagement to identify, at the single-cell level, intracellular proteins involved in the activation process. By digital immunofluorescence microscopy, we localized six isoforms of PKC in antigen-specific T-cell clones activated by APCs. Surprisingly, only PKC-theta translocated to the site of cell contact. Accordingly, in vitro kinase activity assays of PKC immunoprecipitates from the conjugates of T cells and APCs showed a selective increase in the activity of PKC-theta, indicating that the translocated enzyme is active. Several modes of partial T-cell activation that failed to cause PKC-theta translocation also failed to cause T-cell proliferation, further suggesting the involvement of PKC-theta in T-cell activation.

Cardiac anatomy in patients undergoing the Fontan procedure

BACKGROUND

Controversies in nomenclature, especially of hearts with "single ventricle," have clouded discussion and understanding of the anatomy. Many patients with such malformations are submitted to the Fontan procedure as definitive surgical palliation. The spectrum of anatomy among these patients is wide and deserves analysis in an effort to provide a simple framework for description and to eliminate confusion.

METHODS

We reviewed 138 successive patients undergoing the Fontan operation at one institution to demonstrate the variability in pathology.

RESULTS

Only 89 patients (65%) had a univentricular type of atrioventricular connection. All but 5 patients had two ventricular chambers. Among the 49 patients with biventricular atrioventricular connections, 43 had a hypoplastic ventricle that precluded a biventricular repair.

CONCLUSIONS

Full understanding of the malformations that may preclude a "biventricular" repair and hence necessitate a Fontan procedure requires knowledge of the different forms of univentricular atrioventricular connection that, although usually associated with two ventricular chambers, are seldom amenable to a "two-pump repair." Understanding of those types of "biventricular heart" that preclude a two-pump repair (eg, severe hypoplasia of the left ventricle or the right ventricle) or are associated with high risks (eg, straddling atrioventricular valve) is also important.

Self peptides isolated from MHC glycoproteins of non-obese diabetic mice

The non-obese diabetic (NOD) mouse spontaneously develops an insulin-dependent diabetes mellitus that resembles human type I diabetes. This disease can be transferred by purified T cells or cloned T cell lines, implicating an autoimmune T cell attack on the pancreatic beta cells of the islets of Langerhans. As all T cell responses involve recognition of peptides bound to MHC molecules displayed at the cell surface, we have examined self peptides binding to the MHC molecules on spleen cells of the NOD mouse. Peptides eluted from the MHC class I molecule Kd have sequences that conform to known motifs for peptides binding this molecule in other strains of mice. The NOD mouse expresses the unique MHC class II molecule I-Ag7. Peptides eluted from I-Ag7 have sequences that implicate an acidic residue in the C terminus of the peptide as important for binding. The role of this residue in binding has been confirmed by direct peptide-binding analysis. This C-terminal acidic amino acid may interact with an arginine residue in the MHC class II alpha-chain that is exposed when beta-chain residue 57 is mutated to serine, or to the unique beta-chain residue histidine 56. These data may provide valuable insights into the nature of autoantigenic peptides presented by NOD mouse MHC molecules by defining the nature of I-Ag7-peptide binding.

Self peptides isolated from MHC glycoproteins of non-obese diabetic mice

The non-obese diabetic (NOD) mouse spontaneously develops an insulin-dependent diabetes mellitus that resembles human type I diabetes. This disease can be transferred by purified T cells or cloned T cell lines, implicating an autoimmune T cell attack on the pancreatic beta cells of the islets of Langerhans. As all T cell responses involve recognition of peptides bound to MHC molecules displayed at the cell surface, we have examined self peptides binding to the MHC molecules on spleen cells of the NOD mouse. Peptides eluted from the MHC class I molecule Kd have sequences that conform to known motifs for peptides binding this molecule in other strains of mice. The NOD mouse expresses the unique MHC class II molecule I-Ag7. Peptides eluted from I-Ag7 have sequences that implicate an acidic residue in the C terminus of the peptide as important for binding. The role of this residue in binding has been confirmed by direct peptide-binding analysis. This C-terminal acidic amino acid may interact with an arginine residue in the MHC class II alpha-chain that is exposed when beta-chain residue 57 is mutated to serine, or to the unique beta-chain residue histidine 56. These data may provide valuable insights into the nature of autoantigenic peptides presented by NOD mouse MHC molecules by defining the nature of I-Ag7-peptide binding.