Conservative management of mesenchymal hamartomas of the chest wall

Mesenchymal hamartomas of the chest wall are rare benign lesions usually discovered in infancy. The authors present their experience with 3 cases. All of these cases were managed initially conservatively, although 1 child required a thoracotomy and partial tumour resection at 5 months of age because of respiratory compromise. The other 2 children have now reached 5 and 6 years of age with the tumors becoming less prominent. The authors believe many cases can be managed conservatively because malignant change has not been reported, and the lesions often become relatively smaller as the child grows. J Pediatr Surg 36:1346-1349, Copyright (C) 2001 by W.B. Saunders Company.

Flotillin-1-enriched lipid raft domains accumulate on maturing phagosomes

Flotillin-1 was recently shown to be enriched on detergent-resistant domains of the plasma membrane called lipid rafts. These rafts, enriched in sphingolipids and cholesterol, sequester certain proteins while excluding others. Lipid rafts have been implicated in numerous cellular processes including signal transduction, membrane trafficking and molecular sorting. In this study, we demonstrate both morphologically and biochemically that lipid rafts are present on phagosomes, These structures are enriched in flotillin-1 and devoid of the main phagosomes membrane protein lysosomal-associated membrane protein (LAMP1), The flotillin-1 present on phagosomes does not originate from the plasma membrane during phagocytosis but accumulates gradually on maturing phagosomes, Treatment with bafilomycin A1, a compound that inhibits the proton pump ATPase and prevents the fusion of phagosomes with late endocytic organelles, prevents the acquisition of flotillin-1 by phagosomes, indicating that this protein might be recruited on phagosomes from endosomal organelles. A proteomic characterization of the lipid rafts of phagosomes indicates that actin, the alpha- and beta -subunits of heterotrimeric G proteins, as well as subunits of the proton pump V-ATPase are among the constituents of these domains. Remarkably, the intracellular parasite Leishmania donovani can actively inhibit the acquisition of flotillin-1-enriched lipid rafts by phagosomes and the maturation of these organelles. These results indicate that specialized functions required for phagolysosome biogenesis may occur at focal points on the phagosome membrane, and therefore represent a potential target of intracellular pathogens.

Compact clinical MRI magnet design using a multilayer current density approach

In this work, a new method of optimization is successfully applied to the theoretical design of compact, actively shielded, clinical MRI magnets. The problem is formulated as a two-step process in which the desired current densities on multiple, cc-axial surface layers are first calculated by solving Fredholm equations of the first kind. Non-linear optimization methods with inequality constraints are then invoked to fit practical magnet coils to the desired current densities. The current density approach allows rapid prototyping of unusual magnet designs. The emphasis of this work is on the optimal design of short, actively-shielded MRI magnets for whole-body imaging. Details of the hybrid numerical model are presented, and the model is used to investigate compact, symmetric, and asymmetric MRI magnets. Magnet designs are presented for actively-shielded, symmetric magnets of coil length 1.0 m, which is considerably shorter than currently available designs of comparable dsv size. Novel, actively-shielded, asymmetric magnet designs are also presented in which the beginning of a 50-cm dsv is positioned just 11 cm from the end of the coil structure, allowing much improved access to the patient and reduced patient claustrophobia. Magn Reson Med 45:331540, 2001. (C) 2001 Wiley-Liss, Inc.

Chest pain in the dental surgery: A brief review and practical points in diagnosis and management

If a dental patient develops chest pain it must always be managed promptly and properly, i.e., the practitioner immediately stops the procedure and, being aware of the patients's medical history, questions the patient regarding the nature of the pain to help determine the likely diagnosis. It will most likely be a manifestation of coronary artery disease (synonymous with ischaemic heart disease), i.e., angina pectoris or acute myocardial infarction, most usually the former. Angina will usually resolve with proper intervention whereas up to about one-half of myocardial infarction cases will develop cardiac arrest, mostly in the first few hours, and this will be fatal in up to two-thirds of cases. As health care professions, dental practitioners have an inherent duty of care to be able to initiate appropriate care if such a medical emergency occurs.

The socio-religious beliefs and nature of the contemporary Vampire Subculture

The contemporary Vampire Subculture can be defined as a multi-faceted, socio-religious movement with its own distinct collective community and network of participants who share a similar belief system and customary lifestyle that reflect their concept of the vampire. The Vampire Subculture consists of individuals who profess to be 'real vampires', vampire communities of like-minded persons, 'blood-donors' who willingly allow vampires to partake of them, occult-based and mystical-orientated groups that appeal to their spirituality, the blood fetishists, and the live-action vampire role-players. In response, a Christian counter-movement of self-proclaimed 'vampire-slayers' has emerged that actively opposes the vampire subculture and its beliefs and practices. The socio-religious nature of the Vampire Subculture can be best described as a Segmented, Polycentric and Integrated Network of participants.

Current density mapping approach for design of clinical magnetic resonance imaging magnets

Novel current density mapping (CDM) schemes are developed for the design of new actively shielded, clinical magnetic resonance imaging (MRI) magnets. This is an extended inverse method in which the entire potential solution space for the superconductors has been considered, rather than single current density layers. The solution provides an insight into the required superconducting coil pattern for a desired magnet configuration. This information is then used as an initial set of parameters for the magnet structure, and a previously developed hybrid numerical optimization technique is used to obtain the final geometry of the magnet. The CDM scheme is applied to the design of compact symmetric, asymmetric, and open architecture 1.0-1.5 T MRI magnet systems of novel geometry and utility. A new symmetric 1.0-T system that is just I m in length with a full 50-cm diameter of the active, or sensitive, volume (DSV) is detailed, as well as an asymmetric system in which a 50-cm DSV begins just 14 cm from the end of the coil structure. Finally a 1.0-T open magnet system with a full 50-cm DSV is presented. These new designs provide clinically useful homogeneous regions and have appropriately restricted stray fields but, in some of the designs, the DSV is much closer to the end of the magnet system than in conventional designs. These new designs have the potential to reduce patient claustrophobia and improve physician access to patients undergoing scans. (C) 2002 Wiley Periodicals, Inc.

Asymmetric cheating opportunities and partner control in a cleaner fish mutualism

How can cooperation persist if, for one partner, cheating is more profitable than cooperation in each round, while the other partner has no option to cheat? Our laboratory experiments suggest that such a situation exists between the cleaner fish Labroides dimidiatus and its nonpredatory client reef fish species, which actively seek cleaners to have their ectoparasites removed. Clients Ctenochaetus striatus regularly jolted in response to cleaner mouth contact, and these jolts were not linked to the removal of parasites. In addition, cleaners did not search for parasites but fed on mucus when exposed to anaesthetized clients, which could not control the cleaners' behaviour. Field data showed that clients often terminated an interaction immediately after a jolt. Client species with access to only one cleaning station, owing to their small territories or home ranges, terminated interactions mainly by chasing cleaners while clients with access to two or more cleaning stations mainly swam away. Thus, the chasing of cleaners appeared to be a form of punishment, imposing costs on the cleaner at the client's (momentary) expense. Chasing yields future benefits, as jolts were on average less frequent during interactions between cleaners and individuals that had terminated their previous interaction by aggressive chasing. 2002 The Association for the Study of Animal Behaviour.

Parasite distribution on client reef fish determines cleaner fish foraging patterns

Recent evidence suggests that cleaner fish Labroides dimidiatus effectively control parasite densities on client reef fish that actively visit them to have parasites and dead or infected tissue removed. These findings support the hypothesis that clients benefit from cleaning, However, they do not show how cleaners reduce the parasite load of their clients. Cleaners could selectively feed on parasites or parasite removal could be a side product of cleaners foraging indifferently on the client surface, resulting in the removal of healthy mucus and scales also. To investigate cleaner fish foraging behaviour, we infected individuals of the surgeon fish Ctenochaetus striatus, with parasitic monogeneans on one body side, while the other body side was parasite free. We then allowed these clients to interact with L, dimidiatus. We found that the duration of interactions depended on parasite load, and that cleaners spent both more time and took more bites per time unit on the infected than on the uninfected side, Our data thus support the idea that parasite abundance determines food patch quality for cleaners. The overall outcome of cleaning interactions is thus likely to benefit the clients.

Swallowing outcomes following laryngectomy and pharyngolaryngectomy

Objectives: To determine the incidence of dysphagia (defined as the inability to manage a diet of normal consistencies) at hospital discharge and beyond 1 year post-surgery and examine the impact of persistent dysphagia on levels of disability, handicap, and well-being in patients. Design: Retrospective review and patient contact. Setting: Adult acute care tertiary hospital. Patients: The study group, consecutively sampled from January 1993 to December 1997, comprised 55 patients who underwent total laryngectomy and 37 patients who underwent pharyngolaryngectomy with free jejunal reconstruction. Follow-up with 36 of 55 laryngectomy and 14 of 37 pharyngolaryngectomy patients was conducted 1 to 6 years postsurgery. Main Outcome Measures: Number of days until the resumption of oral intake; swallowing complications prior to and following discharge; types of diets managed at discharge and follow-up; and ratings of disability, handicap, and distress levels related to swallowing. Results: Fifty four (98%) of the laryngectomy and 37 (100%) of the pharyngolaryngectomy patients experienced dysphagia at discharge. By approximately 3 years postsurgery, 21 (58%) of the laryngectomy and 7 (50%) of the pharyngolaryngectomy patients managed a normal diet. Pharyngolaryngectomy patients experienced increased duration of nasogastric feeding, time to resume oral intake, and incidence of early complications affecting swallowing. Patients experiencing long-term dysphagia identified significantly increased levels of disability, handicap, and distress. Patients without dysphagia also experienced slight levels of handicap and distress resulting from taste changes and increased durations required to complete meals of normal consistency. Conclusions: The true incidence of patients experiencing a compromise in swallowing following surgery has been underestimated. The significant impact of impaired swallowing on a patient's level of perceived disability, handicap, and distress highlights the importance of providing optimal management of this negative consequence of surgery to maximize the patient's quality of life.

Inherited copper toxicosis in a Bedlington terrier

Inherited copper toxicosis was diagnosed in a Bedlington Terrier using conventional diagnostic methods such as plasma biochemistry, hepatic copper assay, histology and electron microscopy and a recently developed DNA microsatellite marker test. The dog was successfully managed using D-penicillamine and a low copper diet.

Up close and personal on physical education teachers' identity: Is conflict an issue?

Much of the research on teachers' work is informed by role theory, that assumes teachers' identity is largely ascribed. When there are inconsistencies in teachers' and others' expectations for different occupational roles such as physical education teacher and sports coach, 'role conflict' is said to occur. This stud), sought to investigate if role conflict was a major concern for Australian physical education teacher/coaches. Findings, informed by case studies with five teacher/coaches, challenge the assumption that moving between professional responsibilities causes role conflict. Rather, in moving across contexts, the physical education teachers managed inconsistencies in ways that resulted in positive and rawarding work experiences.

High dependency units: Issues to consider in their planning

This review discusses the issues to be considered in establishing new or extending existing high dependency unit (HDU) services. A defined high dependency service becomes cost-effective when patient care requires more than one nurse for three patients. Professional guidelines for HDUs vary and there are no national accreditation criteria. Casemix and service delivery specifications for the HDU need to be defined and agreed upon within the institution. Establishing a new HDU service requires changes to care delivery. Many potential HDU patients are currently managed in general wards or in the intensive care unit. The service should be discussed widely and marketed within the institution, and the development of defined working relationships with the ICU and primary care teams oil the wards is mandatory.

Exploring the learning potential of an artificial life simulation

CULTURE is an Artificial Life simulation that aims to provide primary school children with opportunities to become actively engaged in the high-order thinking processes of problem solving and critical thinking. A preliminary evaluation of CULTURE has found that it offers the freedom for children to take part in process-oriented learning experiences. Through providing children with opportunities to make inferences, validate results, explain discoveries and analyse situations, CULTURE encourages the development of high-order thinking skills. The evaluation found that CULTURE allows users to autonomously explore the important scientific concepts of life and living, and energy and change within a software environment that children find enjoyable and easy to use.

Drawing insight from pictures: The development of concepts of false drawing and false belief in children with deafness, normal hearing, and autism

Theory-of-mind concepts in children with deafness, autism, and normal development (N = 154) were examined in three experiments using a set of standard inferential false-belief tasks and matched sets of tasks involving false drawings. Results of all three experiments replicated previously published findings by showing that primary school children with deafness or autism, aged 6 to 13 years, scored significantly lower than normal-developing 4-year-old preschoolers on standard misleading-container and unseen-change tests of false-belief understanding. Furthermore, deaf and autistic children generally scored higher on drawing-based tests than on corresponding standard tests and, on the most challenging of the false-drawing tests in Experiment 2, they significantly outperformed the normal-developing preschoolers by clearly understanding their own false intentions and another person's false beliefs about an actively misleading drawing. In Experiment 3, preschoolers; outperformed older deaf and autistic children on standard tasks, but did less well on a task that required the drawing of a false belief. Methodological factors could not fully explain the findings, but early social and conversational experiences in the family were deemed likely contributors.

Behaviour of the black flying fox Pteropus alecto: 2. Territoriality and courtship

Flying foxes are commonly thought of as highly social mammals, yet little is known about the dynamics of their social interactions at a day roost. The aim of the present study was to examine the nature of the seasonal activities of territoriality and courtship amongst wild flying foxes in Australia. Focal observations were conducted at two permanent roosts of black flying foxes Pteropus alecto during periods of peak social interaction in the summers of 1999 and 2000 in urban Brisbane, Queensland. Observations of male territoriality were conducted at dawn and began eight weeks prior to the commencement of mating. The majority of defense bouts (87%) consisted of ritualised pursuit, while 13% of bouts involved physical contact expressed as either wrestling or hooking. One male with an unusually large territory took significantly longer to defend it than other males with less territory to defend. Observations of courtship revealed repetitive courtship sequences, including pre-copulatory approaches by the males, copulation attempts and grooming/resting periods. Thirty-four complete courtship sequences incorporating 135 copulation attempts were recorded over two seasons. Females actively resisted courtship approaches by males, forcing males to display a continuous determination to mate over time where determination can be considered an indicator of 'fitness'. The courtship bout length of females with suckling young was significantly longer ((x) over bar +/- SE; 230.9 +/- 22.16 s) than that of females unencumbered by large pups (158.5 +/- 9.69 s), although the length of copulations within those courtships was not (45.6 +/- 5.19 versus 36.2 +/- 3.43 s).