Diagnostic radiography students' attitudes towards gender inclusive pregnancy status checks

INTRODUCTION

Radiographers are responsible for protecting foetuses against ionising radiation and must screen all individuals for pregnancy prior to a pelvic X-ray examination following new guidance from the Society of Radiographers. This includes male, female, transgender, non-binary and intersex patients. Student diagnostic radiographers learn to undertake this screening so this project was designed to understand their attitudes towards doing so.

METHOD

A qualitative study was conducted with third-year students on the BSc Diagnostic Radiography programme at a University in the North West of England. Following ethical approval, focus groups were conducted using open-ended questions to gain insight into how comfortably students conduct Inclusive Pregnancy Status (IPS) checks at seven National Health Service (NHS) Trust clinical placement sites. Students were also asked about their attitudes towards IPS checks. These data were analysed using Clarke and Braun's thematic analysis model.

RESULTS

The analysis of seven focus groups with nineteen participants yielded four themes: education, standardisation, fear of reaction, and placement involvement. Barriers to conducting IPS checks include a lack of staff encouragement as guidance is enforced at the employers' discretion, and a lack of awareness around transgender, non-binary and intersex (TNBI) inclusivity. Students showed a willingness to conduct IPS checks despite this.

CONCLUSION

Age and experience range of participants were limiting factors in this study. Students who had the opportunity to practice and were encouraged to conduct IPS checks on placement felt confident in doing so.

IMPLICATIONS FOR PRACTICE

More training and awareness should be provided surrounding LGBTQ + issues in healthcare. IPS checks should be standardised across placement sites to ensure equal learning opportunities.

Enhanced TLR2 responses in multiple sclerosis

The roles of the microbiome and innate immunity in the pathogenesis of multiple sclerosis (MS) remain unclear. We have previously documented abnormally low levels of a microbiome‐derived Toll‐like receptor (TLR)2‐stimulating bacterial lipid in the blood of MS patients and postulated that this is indicative of a deficiency in the innate immune regulating function of the microbiome in MS. We postulated further that the resulting enhanced TLR2 responsiveness plays a critical role in the pathogenesis of MS. As proof‐of‐concept, we reported that decreasing systemic TLR2 responsiveness by administering very low‐dose TLR2 ligands attenuated significantly the mouse model of MS, experimental autoimmune encephalomyelitis. Studies of Toll‐like receptor responses in patients with MS have been conflicting. Importantly, most of these investigations have focused on the response to TLR4 ligation and few have characterized TLR2 responses in MS. In the present study, our goal was to characterize TLR2 responses of MS patients using multiple approaches. Studying a total of 26 MS patients and 32 healthy controls, we now document for the first time that a large fraction of MS patients (50%) demonstrate enhanced responsiveness to TLR2 stimulation. Interestingly, the enhanced TLR2 responders include a significant fraction of those with progressive forms of MS, a subset of patients considered unresponsive to adaptive immune system‐targeting therapies. Our results suggest the presence of a pathologically relevant TLR2 related innate immune abnormality in patients with both relapsing–remitting and progressive MS. These findings may have significant implications for understanding the role of innate immunity in the pathogenesis of MS.

Poly(ethylene-co-butylene)-b-(styrene-ran-maleic anhydride)2 Compatibilizers via Nitroxide Mediated Radical Polymerization

Telechelic poly(ethylene-ran-butylene) initiator terminated with [tert-butyl[1-(diethoxyphosphoryl)-2,2-dimethylpropyl]amino] nitroxide groups (PEB-(SG1)2) was used to initiate the controlled radical copolymerization of maleic anhydride (MA) and styrene (ST). The ST/MA copolymerizations were performed in 1,4-dioxane at 110°C and resulted in PEB-b-P(ST-ran-MA)2 triblock copolymers with relatively narrow molecular weight distributions ( M ¯ m / M ¯ n ≈ 1.5 ) . Gel permeation chromatography (GPC) indicated that the initiator used was ≈93% efficient. The resulting copolymers were then blended as 20 wt.% dispersions in nylon 6 (PA6) at 230°C. With as little as 10 mol.% of MA in the feed to make the PEB-b-P(ST-ran-MA)2, blends were deemed dynamically compatibilized based on the reduced particle size. All of the PEB-b-P(ST-ran-MA)2/PA6 blends resulted in a minor phase particle size D ¯ vs = 0.1 μm while the PEB-b-P(ST)/PA6 blend had D ¯ vs = 1.15 μm (i.e. no MA in the copolymer). Tensile testing revealed yield stresses and strains decreased steadily from pure PA6 to non-reactive PEB-b-P(ST)2/PA6 to PEB-b-P(ST-ran-MA)2/PA6. However, no difference in tensile properties was observed between PEB-b-P(ST-ran-MA)2/PA6 samples made from PEB-b-P(ST-ran-MA)2 copolymer of varying MA content.

Over-summering behaviour of Atlantic salmon Salmo salar returning to rivers in the Cromarty Firth, north-east Scotland

In 2005, a high percentage (50%) of Atlantic salmon Salmo salar fitted with acoustic transmitters, which entered rivers in the Cromarty Firth area of north-east Scotland, dropped back to the estuary and ascended adjacent rivers after 33-80 days of freshwater residence. Fish residing in non-natal rivers generate mixed stock fisheries, and movements of fish between rivers could increase the risk of disease transmission between catchments.

Habitat use and dispersal of post-smolt sea trout Salmo trutta in a Scottish sea loch system

Post-smolt anadromous brown trout Salmo trutta, sea trout, from two Scottish west coast rivers, the Balgy and Shieldaig, flowing into adjacent sea lochs were tracked simultaneously using arrays of moored acoustic receivers to determine dispersal patterns and loss rates. Fish tended to stay close to their natal rivers for the first 14 day after entering the sea, during which time about half the fish were lost to the study. Although initially the overall pattern of dispersal was similar for individual fish from both rivers, towards the end of the study the groups had converged into one of the loch basins. There were also pronounced individual differences in habitat use with all those fish detected for >42 days exhibiting different patterns of habitat use. Loss rates were similar between the two rivers despite differences in the range of air-breathing predators to which the fish were initially exposed. These findings suggest that any management of predators or other mortality agents should be targeted towards mouths of rivers during and immediately following smolt emigration.

Diagnosis of solid pancreatic masses by endoscopic ultrasound-guided fine-needle aspiration

BACKGROUND

Endoscopic ultrasound (EUS) with fine-needle aspiration (FNA) is increasingly being used in the staging algorithm for pancreatic carcinoma. This allows for a tissue diagnosis, which was previously difficult to obtain. The aim of this study is to assess the utility of EUS-FNA in establishing the diagnosis of solid pancreatic mass lesions in an Australian population.

METHODS

A retrospective review of the EUS databases of St Vincent's Hospital Melbourne and Western Hospital, Melbourne from November 2002 to May 2006 was undertaken. The focus was on patients with a solid pancreatic mass who underwent EUS-FNA. Surgical pathology or long-term follow up was used to identify false-positive or false-negative results.

RESULTS

EUS was undertaken to investigate a solid pancreatic or distal common bile duct mass lesion in 155 patients. Seventy-two of these underwent EUS-guided FNA. Mean age was 68 years. A positive tissue diagnosis of malignancy could be made in 55 (76%). Nine (13%) had benign histology, with 8 (11%) having inadequate tissue obtained from FNA. A later tissue diagnosis of carcinoma was made in eight of those with either benign or inadequate histology, although in all cases there were EUS features diagnostic of malignancy, with FNA limited by technical difficulties. The overall utility of EUS-FNA showed a sensitivity of 87%, specificity 100%, positive predictive value 100%, negative predictive value 52% and overall accuracy 89%.

CONCLUSION

EUS-FNA gives a high return for histological diagnosis of solid pancreatic mass lesions and should be part of the standard management algorithm for pancreatic carcinoma.

Diagnosis of solid pancreatic masses by endoscopic ultrasound-guided fine-needle aspiration

BACKGROUND

Endoscopic ultrasound (EUS) with fine-needle aspiration (FNA) is increasingly being used in the staging algorithm for pancreatic carcinoma. This allows for a tissue diagnosis, which was previously difficult to obtain. The aim of this study is to assess the utility of EUS-FNA in establishing the diagnosis of solid pancreatic mass lesions in an Australian population.

METHODS

A retrospective review of the EUS databases of St Vincent's Hospital Melbourne and Western Hospital, Melbourne from November 2002 to May 2006 was undertaken. The focus was on patients with a solid pancreatic mass who underwent EUS-FNA. Surgical pathology or long-term follow up was used to identify false-positive or false-negative results.

RESULTS

EUS was undertaken to investigate a solid pancreatic or distal common bile duct mass lesion in 155 patients. Seventy-two of these underwent EUS-guided FNA. Mean age was 68 years. A positive tissue diagnosis of malignancy could be made in 55 (76%). Nine (13%) had benign histology, with 8 (11%) having inadequate tissue obtained from FNA. A later tissue diagnosis of carcinoma was made in eight of those with either benign or inadequate histology, although in all cases there were EUS features diagnostic of malignancy, with FNA limited by technical difficulties. The overall utility of EUS-FNA showed a sensitivity of 87%, specificity 100%, positive predictive value 100%, negative predictive value 52% and overall accuracy 89%.

CONCLUSION

EUS-FNA gives a high return for histological diagnosis of solid pancreatic mass lesions and should be part of the standard management algorithm for pancreatic carcinoma.

The link between maltreatment and juvenile firesetting: correlates and underlying mechanisms

OBJECTIVE

Despite the widely held belief that abuse is a risk factor for childhood firesetting, the role of maltreatment in firesetting is largely unexplored. This study reports on a sample of children and adolescents referred to a brief assessment and intervention program for juvenile firesetters. Firesetting histories of maltreated youth were compared to a group of firesetting youth with no maltreatment history.

METHODS

Participants included 205 children and youth aged 4-17 years and their caregivers. Assessments were completed with a standardized protocol. Forty-eight percent of the sample had a history of maltreatment as reported by caregivers; 26% of the sample had experienced more than one type of maltreatment.

RESULTS

When compared to the non-maltreated group, children with histories of maltreatment demonstrated more frequent fire involvement, more versatility regarding ignition sources and targets, and a greater likelihood of an immediate family stressor as a motive for firesetting (all p<.05). Maltreated children were more likely to become involved with fire out of anger (p=.001), and there was also a trend towards higher rates of recidivism (p=.07). Children's externalizing behavior partially mediated the influence of maltreatment on specific fire-related outcomes of children (OR=1.10; 95% CI=1.04-1.17; p=.001).

CONCLUSIONS

Within a juvenile firesetting population, the presence of maltreatment is a risk factor for a more severe course of firesetting. The findings also suggest that the link between maltreatment and firesetting is operating partially through heightened emotional and behavioral difficulties.

PRACTICE IMPLICATIONS

This study demonstrates that maltreatment is a risk factor that contributes to a more severe course of juvenile fire involvement, and that the link between maltreatment and firesetting operates largely through heightened behavioral and emotional difficulties. These findings highlight the need for mental health clinicians to (a) be aware that these two serious clinical issues frequently co-occur, (b) screen for fire-related behaviors and maltreatment during general assessments, and (c) consider maltreatment status when thinking about the risk of firesetting.

Postnatal development of the reproductive system in the grey short-tailed opossum, Monodelphis domestica

Postnatal phenotypic sex differentiation has been investigated in a laboratory marsupial, Monodelphis domestica, as part of a larger study to resolve apparent discrepancies between eutherian and marsupial mammals. These include the formation of sex-specific structures in marsupials prior to gonadal differentiation and the retention in both sexes of structures which are sex-specific in eutherians. The time-course and nature of differentiation was investigated in 131 specimens ranging in age from the day of birth to 56 days. Patent wolffian ducts extend to the urogenital sinus in both sexes at birth, while müllerian ducts are identified on day 1 and grow in a cranio-caudal direction to reach the urogenital sinus on day 6. The male müllerian duct shows signs of regression at its cranial end on day 10 and throughout its length on day 12; its lumen has completely disappeared by day 15. By this time the epididymis and vas deferens have developed from the wolffian duct; their histological differentiation occurs between days 26 and 56. Prostatic buds are identifiable in tissue surrounding the male urethra on day 14. In the female, the wolffian duct is larger than the müllerian duct until day 14; thereafter the wolffian duct begins to regress at its cranial end, disappearing by day 17, whereas the müllerian duct begins to enlarge, converging with its fellow at the urogenital sinus by day 19. Lateral vaginae, vaginal culs-de-sac, uteri and oviducts have differentiated from the müllerian ducts by day 25. Gonads of both sexes are elongated in shape at birth, attached along the medial aspect of the large mesonephroi in the abdominal cavity. However, from day 3 onwards the testis becomes more rounded than the ovary. Degeneration of the male mesonephros begins about day 10 and is almost completed by day 19; the female mesonephros is still relatively large at day 14 though it too has almost disappeared by day 19. By postnatal day 13 the abdominal phase of testis descent is underway and the inguinal phase begins at day 15. Testes have reached the scrotal sac by day 24 and achieve their final position at the base of the scrotum by day 28. In summary, postnatal reproductive tract development and gonadal descent has been examined in this important biomedical model, where differentiation of the wolffian and müllerian ducts takes place after gonadal differentiation, according to the normal eutherian pattern.

The role of androgens in development of the scrotum of the grey short-tailed Brazilian opossum ( Monodelphis domestica)

In eutherian mammals, sex differentiation is initiated by expression of the testis-determining gene on the Y chromosome. Subsequent phenotypic development of the reproductive tract and genitalia depends on the production of hormones by the differentiated testis. In marsupials the mechanisms of phenotypic development may vary from this pattern, as differentiation of the scrotal primordia has been shown to occur before that of the gonad. Thus, the development of the scrotum in the marsupial has been regarded as an androgen-independent process. We have sought to clarify the ontogeny of scrotal development and the appearance of androgen receptor immunoreactivity by examining Monodelphis domesticaembryos/pups from 1 day prior to birth until 2 days after birth. We have also used immunocytochemistry to determine the expression of the key steroidogenic enzyme 3beta-hydroxysteroid dehydrogenase as an indicator of when the developing gonad may be capable of synthesizing androgens. Expression of this enzyme was first detected in the gonads and adrenals of both sexes 1 day prior to birth and before the appearance of scrotal bulges. Androgen receptor immunoreactivity was detected in the scrotal anlagen of male opossum pups as early as 1 day following birth. This finding is significantly earlier than previous reports and coincides with the appearance 1 day after birth of distinct scrotal bulges. Androgen receptor immunoreactivity was also observed in the genital tubercles of male pups, but not female pups, 2 days after birth. These results suggest that androgens may play an important role in the development of the male genitalia at a much earlier stage than that indicated by previously published work and that scrotal development in this species may not be androgen-independent.

The PreOp flexible sigmoidoscopy trainer. Validation and early evaluation of a virtual reality based system

AIM

To demonstrate face and construct validity of a computer based flexible sigmoidoscopy trainer.

METHODS

The PreOp (Immersion Medical, USA) system is a virtual reality based flexible sigmoidoscopy simulator. The system records several performance parameters, such as percentage of colonic mucosa visualized, time taken, and pathlength of endoscope travel. Forty-five subjects were divided into three groups: novice (never performed a lower GI endoscopy), intermediate (5-50 examinations), and trained (greater than 200 examinations). After initial familiarization subjects were assessed three times on a case module. Results showed a nonparametric distribution.

RESULTS

There was a significant difference between all three groups with respect to percentage of mucosa visualized (novice 71.0 +/- 3.7%, intermediate 77.3 +/- 5.6%, expert 84.8 +/- 4.6%, Kruskal-Wallis p <0.001) and efficiency ratio (%mucosa/time, novice 0.163 +/- 0.055, intermediate 0.259 +/- 0.07, expert 0.306 +/- 0.058, p <0.001). The novice group was also slower and had a lower pathlength of instrument travel compared to the others.

CONCLUSION

PreOp virtual reality simulator is a valid discriminator of flexible sigmoidoscopic experience. Its effect on training needs to be explored.

Practice distribution in procedural skills training: a randomized controlled trial

BACKGROUND

"Massed" and "distributed" practice are important concepts in the acquisition of fine motor skills, and may be important in training in procedural skills.

METHODS

A total of 41 novice subjects were recruited and randomized to three groups to receive training on the MIST VR surgical trainer. There were 14 subjects in each of groups A and B and 13 subjects in group C. Training comprised 20 min of massed practice for group A, 20 min of distributed practice in 5 min blocks for group B, and 15 min of distributed practice in 5-min blocks for group C. Following the training period, all groups had a 5-min rest period, followed by a 5-min retention test. Comparisons were made between groups A and B, and groups A and C.

RESULTS

There was a statistically significant difference between groups A and B (p = 0.023) on the retention test, with group B performing better. The increment between the groups was 19% for the overall score on MIST VR. There were also significant differences in the time taken to complete the task during the training phase (p = 0.023, training blocks 3 and 4). Graphical representation suggests no effect between groups A and C, and statistical analysis confirms that the observed difference in median score is not significant.

CONCLUSION

This study demonstrates a benefit for distributed practice over massed practice in learning laparoscopic surgical skills on the MIST VR surgical trainer. This finding has potential implications for skills training in all areas of medicine.

Assessment of surgical competence

This paper examines the issues that arise in the broad area of competence assessment in surgical practice, with particular reference to the objective assessment of technical skill which has historically been the weakest aspect of assessment in surgical training. To facilitate a thorough appraisal of competence, a simple model of surgical practice is advanced, followed by a review of both current and experimental methods of assessing technical skill. The review comprises not only the published literature, but also work (both from the authors' and other groups) that is in progress or under consideration for publication. Significant issues in the implementation of these new technologies, especially the necessary further validation, and the imperative to demonstrate that the process introduced does indeed improve the outcomes are discussed.

Assessment of surgical competence

This paper examines the issues that arise in the broad area of competence assessment in surgical practice, with particular reference to the objective assessment of technical skill which has historically been the weakest aspect of assessment in surgical training. To facilitate a thorough appraisal of competence, a simple model of surgical practice is advanced, followed by a review of both current and experimental methods of assessing technical skill. The review comprises not only the published literature, but also work (both from the authors' and other groups) that is in progress or under consideration for publication. Significant issues in the implementation of these new technologies, especially the necessary further validation, and the imperative to demonstrate that the process introduced does indeed improve the outcomes are discussed.

The use of electromagnetic motion tracking analysis to objectively measure open surgical skill in the laboratory-based model

BACKGROUND

Technical performance has traditionally been assessed subjectively within the operating theater, with few successful attempts at objective analysis. The Imperial College Surgical Assessment Device (ICSAD) has already been shown to be a valid quantitative measure of dexterity in laparoscopic surgical simulation. We describe its application to the assessment of open surgical procedures.

STUDY DESIGN

Fifty-one participants were recruited from four different levels of general surgical experience: basic surgical trainees (n = 12), junior specialist registrars (n = 13), senior specialist registrars (n = 13), and consultants (n = 13). They completed two tasks: a small bowel anastomosis and a vein patch insertion into an artery. Surgical performance was measured with the Imperial College Surgical Assessment Device, a motion analysis system that measures the number of hand movements made and time taken to complete a task. The four groups were compared statistically using the Kruskal-Wallis test (K-W). Pairwise group comparisons used the Mann-Whitney U test and p values were adjusted for multiple comparisons to determine the statistical significance of these comparisons.

RESULTS

Mean values for number of movements and time (secs) for small bowel anastomosis were 2,080/1,236 (basic surgical trainees), 1,673/1,016 (junior specialist registrars), 1,375/862 (senior specialist registrars), and 1,337/782 (consultants), respectively. Comparison of the medians by K-W revealed a p < 0.001 for each variable (No. of movements, time), respectively. Mean vein patch insertion results were 1,653/1,258, 1,297/1,006, 1,090/912, and 925/736 for each of the four groups. Again, comparison of the medians by K-W revealed a p < 0.001 for each variable.

CONCLUSIONS

These findings suggest that hand motion analysis may be an effective objective measure of dexterity in open surgical simulation.

Nuclear factor-kappa B is upregulated in colorectal cancer

BACKGROUND

Chemoresistance may involve the anti-apoptotic transcriptional regulator, nuclear factor-kappa B (NF-kappa B). The purpose of this study was to determine whether chemotherapy induces NF-kappa B activation in a human colon cancer cell line (SW48) and whether NF-kappa B is constitutively activated in colorectal cancer.

METHODS

SW48 cells were incubated with gemcitabine hydrochloride (Gemzar) in the presence and absence of the 26s proteasome inhibitor, MG132, and NF-kappa B binding (electrophoretic mobility shift assay), DNA synthesis (tritiated thymidine uptake), cell viability (3-[4,5-dimethylthiazol-2-yl]-diphenyl-tetrazolium bromide assay), and apoptosis (caspase-3 activity) were measured at 24 hours. NF-kappa B binding (electrophoretic mobility shift assay) was also assayed in 10 colorectal cancer tumors.

RESULTS

SW48 cells demonstrated constitutive NF-kappa B binding that was enhanced by gemcitabine hydrochloride in a dose-dependent manner. MG132 inhibited NF-kappa B binding and enhanced gemcitabine hydrochloride's inhibition of DNA synthesis (gemcitabine hydrochloride = 73% +/- 1.4% vs gemcitabine hydrochloride + MG132 = 6% +/- 0.4%, P <.05), cell killing (gemcitabine hydrochloride = 87% +/- 2.0 vs gemcitabine hydrochloride + MG132 = 25% +/- 1.3%, P <.05), and caspase-3 activity (gemcitabine hydrochloride = 870 +/- 17.4 vs gemcitabine hydrochloride + MG132 = 1075 +/- 20.4, P <.05). NF-kappa B binding was increased in 8 of 10 colorectal cancer tumors compared with adjacent normal mucosa.

CONCLUSIONS

Gemcitabine hydrochloride enhances NF-kappa B binding in a colorectal cancer cell line, whereas inhibition of NF-kappa B enhances gemcitabine hydrochloride's antitumor activity. NF-kappa B is also activated in human colorectal cancer. NF-kappa B may identify chemoresistant tumors, whereas inhibition of NF-kappa B may be a novel, biologically based therapy. (Surgery 2001;130:363-9).

Web-based surgical educational tools

This paper describes work being undertaken as part of the WebSET (Web-based Standard Educational Tools) project. The project is producing a standardised suite of interactive three-dimensional educational tools, delivered across the WWW. The major focus will be the use of open technology and standards, and the production of learning components that can be used as building blocks for further development in a wide range of application areas. Two learning disciplines have been selected for the development of the WebSET tools: surgical training, and physiological education. A high quality consortium from across Europe has been assembled with complementary skills in the technologies needed by the project. The project is partly funded by the European Commission.

Upper-limb function in Australian children with traumatic brain injury: A controlled, prospective study

OBJECTIVE

To describe upper-limb function in children with mild and severe traumatic brain injury (TBI), by using both quantitative and qualitative measures.

DESIGN

Controlled, prospective cohort study with assessment points initially, at 6 months, and at 2 years after TBI.

SETTING

A tertiary pediatric trauma center in Australia.

PATIENTS

Fifty-one children, ranging in age up to 14 years, who were consecutive admissions with TBI. On the basis of initial and persisting abnormal coma score and persistence of posttraumatic amnesia, they were assigned to either a mild (n = 26) or a severely injured (n = 25) group. Thirty children admitted with non-TBI trauma were recruited as a control group.

MAIN OUTCOME MEASURES

Quantitative measures included Bruininks-Oseretsky Test of Motor Proficiency and Peabody Developmental Motor Scales. Qualitative measures included Brunnstrom Recovery Stages (adapted), categoric scales of muscle tone, grasp used when handwriting, quality of writing product, bilateral activity, and splint use.

RESULTS

There was little difference between the groups on the standardized assessments for subjects who could complete the tests. Qualitative measures showed the severe TBI group to have more difficulties with gross arm control, hand control, and hand function.

CONCLUSION

Children with severe TBI experience more and persisting difficulties with upper-limb function. It is essential to include both quantitative and qualitative measures in this type of research.

Gonadal development in mammals at the cellular and molecular levels

In mammals, although sex is determined chromosomally, gonads in both sexes begin development as similar structures. Until recently it was widely held that female development constituted a "default" pathway of development, which would occur in the absence of a testis-determining gene. This master gene on the Y chromosome, SRY in the human and Sry in the mouse, is thought to act in a cell-autonomous fashion to determine that cells in the gonadal somatic population develop as pre-Sertoli cells. Triggering of somatic cell differentiation along the Sertoli cell pathway is therefore a key event; it was thought that further steps in gonadal differentiation would follow in a developmental cascade. In the absence of Sertoli cells, the lack of anti-Mullerian hormone would allow development of the female Mullerian duct and absence of Leydig cells would prevent maintenance of the Wolffian duct. Recent findings that female signals not only maintain the Mullerian duct and repress the Wolffian duct but also suppress the development of Leydig cells and maintain meiotic germ cells, together with the finding that an X-linked gene is required for ovarian development and must be silenced in the male, have shown that the female default pathway model is an oversimplification. Morphological steps in gonadal differentiation can be correlated with emerging evidence of molecular mechanisms; growth factors, cell adhesion, and signaling molecules interact together, often acting within short time windows via reciprocal control relationships.

E-cadherin in the developing mouse gonad

Expression of the cell adhesion molecule E-cadherin in the developing mouse has been investigated by immunocytochemistry and disaggregated organ culture. The principal aims were firstly, to determine whether E-cadherin is expressed in the indifferent gonad and if so with which cell population(s) it is associated. Secondly, to investigate the pattern of expression in the mesonephros, especially in relation to ventral mesonephric tubule cells, which contribute to the somatic cell population of the gonad. Thirdly, to discover whether there are any sex differences in expression of E-cadherin in differentiating gonads. Germ cells in the indifferent gonad showed strong immunoreactivity whereas somatic cells were unstained unless their membranes were in contact with those of germ cells. Positive staining for E-cadherin was found in epithelial cells of the mesonephric duct and tubules. Staining was weak at the ventral margins of the ventral mesonephric tubules. At later stages, germ cell immunoreactivity could be correlated with stages of ovarian differentiation, being reduced or absent between germ cells at 16 days post coitum, when ovigerous cords become dissociated as a prelude to follicle formation. Stronger staining reappeared briefly at 17 days post coitum, the time of follicular cell attachment to oocytes, before waning again 2 days later. Similarly, immunoreactivity in the differentiating testis was initially restricted to the germ cell population but pre-Sertoli cells were strongly positive between 16 and 19 days post coitum. The most striking sex difference was seen in the somatic cell population, where Leydig cells of the testis became strongly positive for E-cadherin from 17 days post coitum onwards. At this time, unlike controls, dissociated cells from gonads of either sex were unable to reform their initial contacts when cultured in the presence of the antibody to E-cadherin, confirming its functional importance.

Ultrastructural studies demonstrate that epithelial polarity is established in cultured mouse pre-Sertoli cells by extracellular matrix components

The effect of three different substrates, laminin, fibronectin and reconstituted basement membrane, on isolated mouse pre-Sertoli cells maintained in vitro has been investigated. Cultures were monitored on a daily basis by phase contrast microscopy, and processed for light and electron microscopy at the end of the culture period. Extra-cellular matrix components have been found to influence Sertoli cell differentiation: both fibronectin and laminin promoted cell adhesion and differentiation, though laminin cultures showed poor viability. Pre-Sertoli cells cultured on reconstituted basement membrane showed the highest degree of differentiation, developing a polarized epithelial phenotype and forming cord-like aggregates; such cultures provide a model system for the investigation of factors involved with gonadal differentiation.

Postnatal development of Leydig cells in the opossum (Monodelphis domestica): an immunocytochemical and endocrinological study

This study involved characterization of Leydig cells of the opossum Monodelphis domestica, functionally by immunocytochemical identification of the enzyme 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) and by measurement of testosterone levels using RIA. Immunostaining for 3 beta-HSD was first detected in a few Leydig cells on Day 16, was increased by Day 24, reached a peak at 4 mo, and was present even in senescent (3 yr) animals. Plasma testosterone was first measurable (0.35 nM) at prepuberty (3.5 mo). Prior to that, plasma testosterone concentrations were uniformly below the level of detection (< 0.3 nM) in both sexes from Day 5 to 2.5 mo. By 4 mo (puberty), plasma testosterone levels in males had risen significantly to 1.53 +/- 0.35 nM, continuing to increase to 1.79 +/- 0.4 nM at 6 mo and peaking at 2.71 +/- 0.29 nM in the adult (1-2 yr). Ovarian testosterone concentrations were consistently lower than those in the testis, as were those of adrenals of both sexes. Thus the testis would appear to be the major source of androgen production throughout life in this species. Our immunocytochemical study suggests that in Monodelphis, puberty is reached at 4 mo, and this was further supported by a rise in circulating testosterone levels at this time.

The AmMYB308 and AmMYB330 transcription factors from antirrhinum regulate phenylpropanoid and lignin biosynthesis in transgenic tobacco

MYB-related transcription factors are known to regulate different branches of flavonoid metabolism in plants and are believed to play wider roles in the regulation of phenylpropanoid metabolism in general. Here, we demonstrate that overexpression of two MYB genes from Antirrhinum represses phenolic acid metabolism and lignin biosynthesis in transgenic tobacco plants. The inhibition of this branch of phenylpropanoid metabolism appears to be specific to AmMYB308 and AmMYB330, suggesting that they recognize their normal target genes in these transgenic plants. Experiments with yeast indicate that AmMYB308 can act as a very weak transcriptional activator so that overexpression may competitively inhibit the activity of stronger activators recognizing the same target motifs. The effects of the transcription factors on inhibition of phenolic acid metabolism resulted in complex modifications of the growth and development of the transgenic plants. The inhibition of monolignol production resulted in plants with at least 17% less lignin in their vascular tissue. This reduction is of importance when designing strategies for the genetic modification of woody crops.

The AmMYB308 and AmMYB330 transcription factors from antirrhinum regulate phenylpropanoid and lignin biosynthesis in transgenic tobacco

MYB-related transcription factors are known to regulate different branches of flavonoid metabolism in plants and are believed to play wider roles in the regulation of phenylpropanoid metabolism in general. Here, we demonstrate that overexpression of two MYB genes from Antirrhinum represses phenolic acid metabolism and lignin biosynthesis in transgenic tobacco plants. The inhibition of this branch of phenylpropanoid metabolism appears to be specific to AmMYB308 and AmMYB330, suggesting that they recognize their normal target genes in these transgenic plants. Experiments with yeast indicate that AmMYB308 can act as a very weak transcriptional activator so that overexpression may competitively inhibit the activity of stronger activators recognizing the same target motifs. The effects of the transcription factors on inhibition of phenolic acid metabolism resulted in complex modifications of the growth and development of the transgenic plants. The inhibition of monolignol production resulted in plants with at least 17% less lignin in their vascular tissue. This reduction is of importance when designing strategies for the genetic modification of woody crops.

Testis development in the opossum Monodelphis domestica

Testis development in the grey short-tailed opossum, Monodelphis domestica, was investigated by light and electron microscopy in 180 animals. On the day of birth, half the karyotyped males were found to have histologically differentiated testes. By day (d) 1 testicular cords were clearly distinguished in all XY gonads and the tunica albuginea was fully developed. At this stage the large and pale primordial germ cells could be differentiated from dark pre-Sertoli cells. From d 3 the testis became progressively rounded and testicular cords were surrounded by peritubular cells. Leydig cells were then distinguishable by the expected ultrastructural features of steroidogenically active cells, showing abundant vesicles of SER, extensive mitochondria with tubular cristae and numerous lipid inclusions. Subsequently these cells formed clusters and were surrounded by envelope cells until wk 12. Testes were located in the abdomen, attached to the large mesonephroi, until d 24 after birth when they began their descent to the scrotal sac. From 7 wk the interstitial tissue became less cellular. At the prepubertal stage (12 wk), the seminiferous tubules lacked lumina. Leydig cell cytoplasm was electron-dense with increased amounts of SER forming parallel profiles. By 4 mo (pubertal stage), seminiferous tubules were patent and various spermatogenic stages, including spermatozoa, were seen for the first time. Leydig cells then greatly outnumbered other interstitial tissue cells and were closely-packed around blood vessels but no longer clustered by envelope cells; their SER was very highly organised into masses of parallel arrays and lipid inclusions were reduced. In the adult (1 y) Leydig cells reached their greatest size; their morphological features resembled those seen at 4 mo except that lipid inclusions were sparse. In ageing Leydig cells (2-3 y), large amounts of SER were present but disorganised.

Pseudomonas aeruginosa outbreak associated with a contaminated blood-gas analyser in a neonatal intensive care unit

Over a 10 month period in a neonatal intensive care unit there was an outbreak of infection caused by Pseudomonas aeruginosa (resistant to ticarcillin, timentin) which involved 24 newborns. There was extensive morbidity and mortality (38%) associated with the infections, which presented as septicaemia (N = 6) (five succumbed and four had coexisting pneumonia), pneumonia (N = 6), meningitis (one, died), conjunctivitis (N = 1), otitis externa (N = 1), conjunctivitis plus otitis externa (N = 1). In addition there were two pseudosepticaemias and six colonized infants, three of whom were treated for the presence of P. aeruginosa in endotracheal aspirates. There was always at least one baby colonized or infected with P. aeruginosa during the outbreak. Environmental surveillance and genomic DNA fingerprinting of isolates identified the blood gas analyzer port as the likely reservoir for the outbreak. Further spread of the organism did not occur after commencement of staff education on vigilant and careful handwashing, especially after use of the blood-gas analyser.

Spatial distribution of acid-volatile sulphide concentration and metal bioavailability in mangrove sediments from the Brisbane River, Australia

Acid-volatile sulphide (AVS) was measured at regular positions along eight transects through a mangrove forest in the Brisbane River, Queensland, Australia. Concentrations ranged from 0.33 to 22.61 micromol S g(-1) sediment dry weight. There was no correlation between AVS concentration and the proportion of clay-sand in the sediment, but sediments with high AVS concentrations tended to contain more water (rs=0.43; p=0.01). AVS concentrations were used to assess the potential bioavailability of the sediment heavy metal burden. The spatial variability of potential bioavailability was high and depended to a great extent on which metals were considered as part of the AVS complexing system. It is suggested seasonal variations would further increase the observed variability in bioavailability. This variation should be taken into account when monitoring and assessing long-term trends in sediment toxicity.

The social adjustment of deaf adolescents in segregated parially integrated and mainstreamed settings

This study examined the social adjustment of deaf adolescents enrolled in segregated (&egr; = 39), partially integrated (&egr; = 15), and mainstreamed (&egr; = 17) settings, comparing them with a control group of hearing students (&egr; = 88). Segregated students showed the lowest levels of adjustment overall. Partially integrated students reported better adjustment overall. Partially integrated students reported better adjustment than mainstreamed students with deaf peers; mainstreamed students reported better adjustment than partially integrated students with hearing peers, showing the same levels of adjustment with hearing peers as hearing students. Regardless of placement, deaf students reported better or equal adjustment with deaf than with hearing peers. Social adjustment with deaf peers was related to American Sign Language (ASL) skill and adjustment with hearing peers to spoken English. These findings suggest tht deaf students can benefit from both segregated and integrated placements as complememtary forms of social experience that each contribute to overal adjustment.

Firesetting during the preschool period: assessment and intervention issues

OBJECTIVE

To describe a methodology of assessing preschoolers involved in firesetting incidents, and outline the psychiatric implications of firesetting incidents in young children.

METHOD

To outline The Arson Prevention Program for Children and present case vignettes.

RESULTS

The heightened risk of burn injury or fatality in fires caused by young children is highlighted and practical suggestions for facilitating the immediate safety of the child and family are presented.

CONCLUSION

Despite the popular notion that fire interest and play is relatively benign in young children, the cases show that, as with older children, firesetting in preschoolers can be associated with serious child and/or family psychopathology.

An urban outbreak of visceral leishmaniasis in Natal, Brazil

The epidemiological pattern of visceral leishmaniasis in north-eastern Brazil is changing. The disease was typically seen in rural, endemic areas, but is now occurring as an epidemic in the city of Natal where 316 cases have been reported since 1989; 49% were in children less than 5 years of age. The principle clinical and laboratory findings were weight loss, fever, hepato-splenomegaly, anaemia, leucopenia and hypergammaglobulinaemia. Elevated transaminases and hyperbilirubinaemia were also observed. The diagnosis was confirmed in 87% of cases by identifying amastigotes in aspirates from bone marrow or spleen. Five isolates were identified as Leishmania (L.) chagasi by isoenzyme analysis. The mortality rate was 9%; all deaths occurred during the first week in hospital. One person had concurrent human immunodeficiency virus infection. Among 210 household contacts and neighbours of patients from the endemic area examined for evidence of L. (L.) chagasi infection, 6 additional cases of visceral leishmaniasis were diagnosed. Thirty-eight percent of house-mates and neighbours gave a positive Montenegro skin test reaction, indicating prior subclinical infection.

An investigation of the migratory potential of mouse oocytes in vitro

This investigation was undertaken to determine the potential of mouse oocytes for migratory activity using bisected ovaries in vitro. Bisection allowed larger medullary oocytes to be brought nearer to the surface; in this way the migratory potential of all oocytes could be studied. Observations were made following 48 h culture to allow for recovery from any initial traumatic effects resulting from bisection. Ovaries were explanted from fetuses at d 15 postcoitum and from neonatal and postnatal mice (d 1-7, 11, 12 and 14 of life) and examined by scanning and transmission electron microscopy. Oocytes were extruded from the surface and a sequence of events was inferred. Cells superficial to the oocyte sloughed off, exposing the oocytes which showed the migratory phenotype as they emerged onto the surface. Here each oocyte became rounder and was finally extruded, leaving a 'crater'. Scanning electron microscopy of the explant surface allowed counts to be made of emergent oocytes. The number of explants showing emergent oocytes was at a maximum when ovaries were removed at the end of the first week postnatum; the mean number of oocytes emerging from each also peaked at this time. Numbers of migratory oocytes declined in ovaries aged 11 d at explantation and by d 14 only 66% of explants showed oocytes at the surface. The distribution of oocytes of various sizes at the surface suggests that both small cortical oocytes and larger medullary oocytes can express the migratory phenotype. Transmission electron microscopy verified structural integrity of the emerging oocytes and revealed their relationship to underlying cells.

Do beans and oat bran add to the effectiveness of a low-fat diet?

The effects of consuming an increased amount of soluble fibre as oat bran or beans were examined in 40 free-living hypercholesterolaemic men and women. The subjects were initially established on a low-fat background diet (29% of energy from fat) and then 55 g low-fibre oat bran, 55 g high-fibre oat bran or 80 g mixed cooked beans were added to their diet in random order for 6 week periods. Body weight and overall composition of the diet did not change. Plasma cholesterol and low-density lipoprotein cholesterol (LDL-C) were unchanged. High-density lipoprotein cholesterol (HDL-C) was significantly higher on all three intervention diets than on the lower fibre run-in diet. Supplementation of a moderately low-fat diet with palatable quantities of oat bran or beans without changing the overall fat intake does not appear to significantly lower cholesterol but may have a benefit by increasing HDL-C and reducing the ratio of LDL-C to HDL-C.

Oocyte numbers are reduced in developing mouse ovaries cultured in testis-conditioned medium

Reduced numbers of oocytes were present in fetal ovaries of 13 d post coitum (dpc) mice, cultured for 4 d in medium conditioned (-CM) for 2 d by 13 dpc testes, compared with ovaries maintained in standard unconditioned medium. This effect was abolished by heat-inactivation of the testis-CM. Electrophoretic analysis of conditioned media revealed differences between testis-CM and ovary-CM. Ovarian differentiation was otherwise unaffected by the testis-CM and gonadal volume was not significantly reduced. Organisation of ovigerous cords proceeded, even though the full complement of oocytes was absent, and connective tissue septa developed normally between the small cords. The reduction in oocyte numbers occurred without any inhibition of müllerian duct development. Since others, using transgenic mice, have shown, that higher concentrations of antimüllerian hormone are required to decrease oocyte numbers than are necessary for duct regression, our results suggest that an additional factor is involved in producing this modified effect.

Control of anthocyanin biosynthesis in flowers of Antirrhinum majus

The intensity and pattern of anthocyanin biosynthesis in Antirrhinum flowers is controlled by several genes. We have isolated six cDNA clones encoding enzymes in the pathway committed to flavonoid biosynthesis and used these to assay how the regulatory genes that modify colour pattern affect the expression of biosynthetic genes. The biosynthetic genes of the later part of the pathway appear to be co-ordinately regulated by two genes, Delila (Del), and Eluta (El), while the early steps (which also lead to flavone synthesis) are controlled differently. This division of control is not the same as control of anthocyanin biosynthesis by the regulatory genes R (S) and C1 in maize aleurone, and may result from the adaptive significance of different flavonoids in flowers and seeds, reflecting their attractiveness to insects and mammals respectively. El and del are probably involved in transcriptional control and both genes appear to be able to repress expression of some biosynthetic genes and activate expression of others.