How to select the doctors of the future.

Although previous academic performance is acknowledged as the best predictor of achievement in medical school, no one has succeeded in finding a selection method which will choose students who will become doctors with the qualities the community expect. Australian medical schools use various selection methods. It could well be argued that the most important phase in the selection process is informed decision-making by potential applicants. More effort should be made by medical schools to achieve this.

Medical student education: what it costs and how it is funded.

The cost to Sydney University to educate a medical student in 2010 was obtained by dividing the total teaching costs by the number of students. This showed the annual cost to educate one medical student was $53,093. Sixty-one per cent comprised salaries. Fifty-three per cent is met by Commonwealth funding and the Higher Education Loan Programme. Fees from international medical students contributed a margin of only 2% towards total education costs. The shortfall of 45% is provided from other sources within the university. This cross-subsidisation may not be sustainable.

Ongoing outbreak of mumps infection in Oban, Scotland, November 2010 to January 2011.

We report on an ongoing outbreak of 119 cases of mumps virus infection in the Oban area of Scotland,from 29 November 2010 to 31 January 2011. The median age of cases was 20 years, with the highest incidence in the 13-19-year-olds. A total of 53 cases had received two doses of measles-mumps-rubella (MMR) vaccine,in accordance with the United Kingdom vaccination schedule, while 33 had received only one dose and 30 had not been vaccinated.

Advances in the microscopy of osteoarthritis.

This review describes recent contributions made by microscopy to the understanding of osteoarthritis, a clinical syndrome the pathological features of which are well defined by classical white light microscopy. The fluorescence and reflected light, conventional and scanning optical microscopy of excised osteoarthritic tissue preparations, from human and animal sources, has enabled the identification of cell proteins such as S100, of matrix components such as the proteoglycans and collagens, and of adhesion molecules including fibronectin, the integrins and tenascin. Comparable microscopic studies have been made of cell and tissue culture preparations of osteoarthritic cartilage and synovium. Scanning optical microscopy also allows the rapid measurement, in hydrated osteoarthritic tissues, of cell density, cell size, surface roughness and other parameters. The importance of water in sustaining the physical attributes of cartilage is accepted and new forms of electron microscopy can play important parts in the study of unfixed osteoarthritic cartilage. These methods include the low temperature scanning electron microscopy and electron probe x-ray microanalysis of hydrated bulk material and the high resolution transmission electron microscopy of low temperature replicas of cartilage surfaces. Understanding of osteoarthritis has been facilitated by these advances and will continue to be enhanced as new techniques of microscopy evolve.

The effect of aluminium coating on elemental signals in X-ray microanalysis.

It has been determined that, in the normal range of aluminium coating thicknesses used to remove charge from non-conducting specimens in the electron microscope, no detectable influence on the elemental signals obtained in X-ray microanalysis is observed. This is in contrast to a previous report (Hopkins et al., J. Electron Microsc. Tech., 18:176-182, 1991) of a reduction in elemental signal with increasing aluminium coating thickness. An explanation of errors in the previous interpretation is provided.

Planing frozen hydrated plant specimens for SEM observation and EDX microanalysis.

A procedure is described for forming a flat face on a frozen piece of plant tissue, which may then be observed fully-hydrated or lightly etched, and coated or uncoated with a metal film, in scanning electron microscopy (SEM). The frozen sample was planed with a glass knife at -80 degrees C in a cryo-ultramicrotome. The sections were discarded, and the planed block face placed on the cold stage in the microscope column, either for observation uncoated at low kV, or for light etching (-90 degrees C) to reveal the cell outlines. If a higher accelerating voltage was needed, the face was given an evaporative coating of Al in the cryo-preparation chamber and returned to the column. The advantages of the planed face over the usual fracture face are illustrated: imaging at a chosen rather than a chance position; clearer cellular and subcellular detail; preservation of hydrated gels like mucilage and swollen cell walls; the possibility of making serial parallel sections through the same piece of tissue; opportunities for accurate morphometric analyses on the planed face; capacity to produce longitudinal sections; preservation of very delicate structures that are destroyed by fixation and drying. A major advantage of the Al-coated planed face is the increased accuracy of energy-dispersive X-ray (EDX) microanalyses on a smooth rather than a rough surface. Tests are included which show that neither the light etching employed, nor successive planing, interferes with the analyses of elements in the frozen face.

Preparation of aqueous standards for low temperature X-ray microanalysis.

A technique, using Nuclepore polycarbonate membrane filters as a containing medium for very small volumes of ionic standard solutions, to produce homogeneous ice standards is described. The standards are suitable for use in a scanning electron microscope. The relationship between elemental X-ray counts and ionic concentration is found to be linear. The method is rapid and simple. Minimum detectable concentrations are given.

INTRACELLULAR ION CONCENTRATIONS IN BRANCHIAL EPITHELIAL CELLS OF BROWN TROUT (SALMO TRUTTA L.) DETERMINED BY X-RAY MICROANALYSIS

The intracellular concentrations of sodium, chloride, phosphorus and potassium under normal conditions in pavement epithelial (PE) cells of brown trout (Salmo trutta) gill were 66, 51, 87 and 88 mmol l-1 respectively. The concentrations of these elements under identical conditions in mitochondria-rich (MR) cells were not significantly different, except for that of chlorine, which was lower in MR cells (40 mmol l-1). The concentration of sodium in the PE cells decreased slightly after exposure of the fish to low external [Na+] (25 µmol l-1) for 7 days but increased greatly within 5 min of subsequent exposure to 1 mmol l-1 external Na+. These changes in external [Na+] had no significant effect on MR cells. Exposure of fish to low [Cl-] (25 µmol l-1) had no effect on PE or MR cells, but on exposure to 1 mmol l-1 Cl- the concentrations of chlorine, phosphorus and potassium in both types of cells increased, whilst the intracellular sodium concentration decreased only in MR cells. The PE cells were little affected by exposure of the fish to the carbonic anhydrase inhibitor acetazolamide. In contrast, 0.5 mmol l-1 external acetazolamide caused a significant decrease in intracellular phosphorus, chlorine and potassium concentrations in MR cells. This suggests that the PE cells are the sites of sodium uptake in the gills of the brown trout and that chloride uptake occurs via the MR cells. These results are discussed with respect to the sites and possible mechanisms of ionic exchange in freshwater vertebrates.

Effect of tissue culture storage on the in vivo survival of canine osteochondral allografts.

In vitro studies in our laboratory have shown that the biomechanical and biochemical characteristics of osteochondral grafts can be preserved for as long as 28 days under tissue culture conditions. This study represents an attempt to extend these results to an in vivo model. In adult mongrel dogs, either an autograft, a fresh allograft, or a stored allograft was placed in a standardized defect on the weight-bearing surface of the medial femoral condyle. The stored grafts were kept at 4 degrees C in tissue culture medium for 14 days prior to implantation. The animals were killed at 12 weeks. Cartilage from the contralateral knee served as a control. The modulus and permeability of the cartilage were assessed with confined compression creep tests. The collagen and glycosaminoglycan contents were measured, and the cartilage was analyzed histologically with hematoxylin and eosin and safranin O stains. Grossly, the cartilage appeared viable at harvest. The histologic results were similar in the treatment groups, with the same spectrum of mild degenerative changes being noted in each group. The glycosaminoglycan content was significantly less in the autograft group than in its control group and than in the fresh allograft group. The glycosaminoglycan content did not differ significantly between fresh and stored allografts. The collagen content, modulus, and permeability did not differ either between experimental and control groups or between graft types. Our results support the conclusion that osteochondral allografts can be stored for as many as 14 days without significantly affecting the results of the procedure.

Comparative injury rates of uninjured, anterior cruciate ligament-deficient, and reconstructed knees in a skiing population.

To evaluate the risks of skiing after anterior cruciate ligament injury with or without reconstruction, we performed a 3-year study of 5646 skiers employed by a large ski resort. All skiers underwent knee ligament examinations before entering the study. The participants were divided into three groups based on whether they had never had an anterior cruciate ligament injury (N = 4748), were unilaterally deficient of the ligament (N = 138), or had undergone a unilateral reconstruction of the ligament at least 1 year before (N = 274). The rates of knee injuries requiring evaluation by a physician or time off work were calculated. The results of the reconstructed knees were further evaluated to determine whether ligament repair with semitendinosus/gracilis or patellar tendon autograft had a higher injury rate. Compared with knees with intact anterior cruciate ligaments, ligament-deficient knees had a 6.2-times higher rate of injuries, and knees in which the ligament had been reconstructed had a 3.1-times higher rate. The differences between each of the three groups were significant. Injuries to ligament-intact knees were less severe, with 13% requiring surgery, while 39% of the injuries in the ligament-deficient and 41% of the injuries in the reconstructed-ligament knees required surgery. The rates of injury for the graft types were not significantly different, but skiers with a semitendinosus/gracilis tendon autograft were significantly more likely to rupture their graft than skiers with a patellar tendon autograft.

Chitin helicoids accompany protein helicoids in the periostracum of a whelk, Buccinum.

The periostracum of the marine gastropod Buccinum has a helicoidal arrangement of its principal constituent which is a fibrous protein (Hunt and Oates, 1978). Chitin, chemically and physically identified, is present at a concentration of about 6% of the dry weight and can be seen in dispersates of whole periostracum as long fibrils and ribbons between 3 and 14 nm diameter. Deproteinization with hot alkali removes all protein leaving a chitinous 'ghost' of the periostracum. Dispersates, examined negatively stained, show only chitin fibrils and ribbons while sectioned material demonstrates a tenuous, part orthogonal, part helicoidal, architecture based on the chitin residue. The relative roles of the protein and polysaccharide components is speculated upon and comparisons with arthropod cuticle drawn.

Personality development following sexual abuse.

Thirty-seven girls and twelve boys who had been sexually abused at an average of 2.6 years previously were traced and reviewed. The nonoffending parents participated in a structured interview and the children were assessed using the Piers-Harris Self-Concept Scale and the Achenbach Child Behavior Checklist. Each child was matched with a child not known to have been sexually abused and these control children underwent a similar psychological assessment. Interviews with the nonoffending parents found that 76% of the children were thought to be less confident than before, 30% had fewer friends, and 20% were more aggressive. Increased sexual awareness was noted in 24%. School teachers reported that 28% still had behavior problems, 17% had repeated a year at school, and a further 17% had deteriorated in their school work. The sexually abused girls had significantly lower self-esteem than the control girls. There was no difference in self-esteem between the control and the sexually abused boys. There was a higher incidence of stranger assault in the boys compared with the girls. The Child Behavior Checklist completed by the parents, the Teacher Report Form, and the Youth Self-Report of the Child Behavior Checklist showed that a highly significant proportion of sexually abused children fell into the clinical range. Sexual abuse appears to have long-term adverse consequences for many of the victims. This may have implications for their ability to relate to others, for the adult friendships they will make, and eventually for the way they will relate to their own children.

Localization of thymosin alpha 1 production to thymus medullary epithelial cells by use of monoclonal antibodies.

The thymus is an endocrine organ which modulates T-cell immunity through the production of protein like peptides such as the thymosins. Thymosin alpha 1 was the first biologically active peptide isolated and sequenced from the partially purified thymic preparation, thymosin fraction 5, and has been extensively studied. Using synthetic Thymosin alpha 1, a heterologous rabbit antiserum has been raised and a radioimmunoassay has been developed. Although thymosin alpha 1 antibodies have been used in several histological studies, their use is limited by potential nonspecific cross-reactivities, unpredictable heterogenicity, variable affinities, and a limited unstandardized supply. In the studies, reported here, eight anti-thymosin alpha 1 monoclonal antibodies (MAbs) were produced by somatic cell fusion between spleen cells from immunized BALB/c mice and P3x64 Ag8.653 myeloma cells. The MAbs were screened for anti-thymosin alpha 1 specificity in a solid phase ELISA and a liquid phase RIA. Only those clones which secreted specific antibody as detected by both procedures were characterized for their heavy chain class and epitope specificity. The anti-thymosin alpha 1 monoclonal antibodies were then used for indirect immune fluorescence studies of perfused rat thymus. Thymosin alpha 1 containing cells were found primarily in the thymic medulla, confirming previous studies using the heterologous antisera. These studies demonstrated the specificity of the anti-thymosin alpha 1 monoclonal antibodies for immunochemical studies of intra- and extra-thymic localization of thymosin alpha 1. They also provide an important reagent for biological studies of the role of thymosin alpha 1, in vitro and in vivo.

Children's memories for stressful and non-stressful events.

Two groups of children aged between 4 and 12 years were studied to look at the effect of stress, time and type of questioning on memory. One group comprised 17 children having a blood sample taken as part of their medical care. The other group of 24 children were studied after reacting with a friendly stranger at their school. Memory was tested either four to ten days after the event or after three to six weeks. Memory was assessed by free recall, by questioning with cues, by structured questions, by leading or misleading questions and by asking the children to identify the blood-collection technician or friendly stranger from a photographic line-up. There was no difference between memory for the stressful or nonstressful events. The older children performed better in free recall although what the younger children did recall was highly accurate. The use of cues facilitated recall in all age groups. Children aged four to six years were less accurate than those aged seven to 12 years when objective questioning was used. Errors were more likely to be errors of omission than of commission in all age groups. Memory was less accurate after the longer time interval. With increasing interest in the reliability of children as witnesses, methods need to be found which will enable the child witness to give the maximum amount of accurate information. Those likely to be working with the child witness need to develop skills in talking with young children.

Models of planned change and research utilization applied to product evaluation.

In the maintenance of an intravascular catheter, a large children's hospital used a needleless valve device. After frequent observations of stagnant blood around the valve, the clinical nurse specialist (CNS) organized a multidisciplinary team to determine how to provide better care and maintenance for the intravascular device and the child. To guide the process, the Iowa Model for Research-Based Practice to Promote Quality Care was selected for the study, and Havelock's Theory of Planned Change was used. The CNS roles of educator, researcher, and collaborator enabled the CNS to be an effective change agent.