Movement kinematic and postural control differences when performing a visuomotor skill in real and virtual environments

Immersive technologies, like virtual and mixed reality, pose a novel challenge for our sensorimotor systems as they deliver simulated sensory inputs that may not match those of the natural environment. These include reduced fields of view, missing or inaccurate haptic information, and distortions of 3D space; differences that may impact the control of motor actions. For instance, reach-to-grasp movements without end-point haptic feedback are characterised by slower and more exaggerated movements. A general uncertainty about sensory input may also induce a more conscious form of movement control. We tested whether a more complex skill like golf putting was also characterized by more consciously controlled movement. In a repeated-measures design, kinematics of the putter swing and postural control were compared between (i) real-world putting, (ii) VR putting, and (iii) VR putting with haptic feedback from a real ball (i.e., mixed reality). Differences in putter swing were observed both between the real world and VR, and between VR conditions with and without haptic information. Further, clear differences in postural control emerged between real and virtual putting, with both VR conditions characterised by larger postural movements, which were more regular and less complex, suggesting a more conscious form of balance control. Conversely, participants actually reported less conscious awareness of their movements in VR. These findings highlight how fundamental movement differences may exist between virtual and natural environments, which may pose challenges for transfer of learning within applications to motor rehabilitation and sport.

Alcohol, gender, and violence: Factors influencing blame for partner aggression

Alcohol use has been associated with intimate partner violence (IPV) and reduced perpetrator blameworthiness, but this finding is not universal. Researchers examining alcohol and IPV-related blame often utilize vignettes depicting perpetrators who are sober and compare this to perpetrators depicted as more or less intoxicated. In this study, participants read one of three vignettes depicting male-to-female physical IPV. We compared participants' blame attributions across three conditions: perpetrator sober, perpetrator intoxicated-infrequent drinker, and perpetrator intoxicated-frequent drinker. Alcohol did not mitigate perpetrator blameworthiness for the assault; however, only the intoxicated-frequent drinker was rated as more blameworthy for his violence than the sober perpetrator. Participants also reported their own IPV perpetration, drinking behaviors, and gender role beliefs. Traditional gender role beliefs and a history of IPV perpetration were associated with shifting some of the blame onto the victim, and this was true for both men and women, especially when the perpetrator was described as a frequent drinker. Researchers should consider whether their alcohol vignettes might depict a behavior as reflecting the situation or the drinker's character, as this may impact their results. Furthermore, different observer characteristics may differentially predict blame attribution.

Finding gaps in routine TB surveillance activities in Bangladesh

BACKGROUND :

TB was the leading cause of death from a single infectious pathogen globally between 2014 and 2019. Fine-scale estimates of TB prevalence and case notifications can be combined to guide priority-setting for strengthening routine surveillance activities in high-burden countries. We produce policy-relevant estimates of the TB epidemic at the second administrative unit in Bangladesh.

METHODS :

We used a Bayesian spatial framework and the cross-sectional National TB Prevalence Survey from 2015–2016 in Bangladesh to estimate prevalence by district. We used case notifications to calculate prevalence-to-notification ratio, a key metric of under-diagnosis and under-reporting.

RESULTS :

TB prevalence rates were highest in the north-eastern districts and ranged from 160 cases per 100,000 (95% uncertainty interval [UI] 80–310) in Jashore to 840 (UI 690–1020) in Sunamganj. Despite moderate prevalence rates, the Rajshahi and Dhaka Divisions presented the highest prevalence-to-notification ratios due to low case notifications. Resolving subnational disparities in case detection could lead to 26,500 additional TB cases (UI 8,500–79,400) notified every year.

CONCLUSION :

This study is the first to produce and map subnational estimates of TB prevalence and prevalence-to-notification ratios, which are essential to target prevention and treatment efforts in high-burden settings. Reaching TB cases currently missing from care will be key to ending the TB epidemic.

Substance use patterns in 9-10 year olds: Baseline findings from the adolescent brain cognitive development (ABCD) study

BACKGROUND

The Adolescent Brain Cognitive Development ™ Study (ABCD Study®) is an open-science, multi-site, prospective, longitudinal study following over 11,800 9- and 10-year-old youth into early adulthood. The ABCD Study aims to prospectively examine the impact of substance use (SU) on neurocognitive and health outcomes. Although SU initiation typically occurs during teen years, relatively little is known about patterns of SU in children younger than 12.

METHODS

This study aims to report the detailed ABCD Study® SU patterns at baseline (n = 11,875) in order to inform the greater scientific community about cohort's early SU. Along with a detailed description of SU, we ran mixed effects regression models to examine the association between early caffeine and alcohol sipping with demographic factors, externalizing symptoms and parental history of alcohol and substance use disorders (AUD/SUD).

PRIMARY RESULTS

At baseline, the majority of youth had used caffeine (67.6 %) and 22.5 % reported sipping alcohol (22.5 %). There was little to no reported use of other drug categories (0.2 % full alcohol drink, 0.7 % used nicotine, <0.1 % used any other drug of abuse). Analyses revealed that total caffeine use and early alcohol sipping were associated with demographic variables (p's<.05), externalizing symptoms (caffeine p = 0002; sipping p = .0003), and parental history of AUD (sipping p = .03).

CONCLUSIONS

ABCD Study participants aged 9-10 years old reported caffeine use and alcohol sipping experimentation, but very rare other SU. Variables linked with early childhood alcohol sipping and caffeine use should be examined as contributing factors in future longitudinal analyses examining escalating trajectories of SU in the ABCD Study cohort.

Sexting Coercion as a Component of Intimate Partner Polyvictimization

We examined the role of sexting coercion as a component of the intimate partner abuse (IPA) construct among young adults to determine whether sexting coercion would emerge alongside other forms of partner aggression as a cumulative risk factor for psychological, sexual, and attachment problems. In a sample of 885 undergraduates (301 men and 584 women), 40% had experienced some type of coercion. Although there was some overlap between sexual coercion and sexting coercion (21% of participants had experienced both), some individuals had experienced only sexting coercion (8%) and some only sexual coercion (11%). Women were more likely than men to be coerced into sexting. Both sexting coercion and sexual coercion were significantly and independently related to negative mental health symptoms, sexual problems, and attachment dysfunction, and, notably, sexting coercion was found to be a cumulative risk factor for nearly all of these negative effects. These data support the idea that digital sexual victimization is a new component of IPA polyvictimization, potentially increasing the negative effects experienced by victims of multiple forms of partner aggression.

Sexting Coercion as a Component of Intimate Partner Polyvictimization

We examined the role of sexting coercion as a component of the intimate partner abuse (IPA) construct among young adults to determine whether sexting coercion would emerge alongside other forms of partner aggression as a cumulative risk factor for psychological, sexual, and attachment problems. In a sample of 885 undergraduates (301 men and 584 women), 40% had experienced some type of coercion. Although there was some overlap between sexual coercion and sexting coercion (21% of participants had experienced both), some individuals had experienced only sexting coercion (8%) and some only sexual coercion (11%). Women were more likely than men to be coerced into sexting. Both sexting coercion and sexual coercion were significantly and independently related to negative mental health symptoms, sexual problems, and attachment dysfunction, and, notably, sexting coercion was found to be a cumulative risk factor for nearly all of these negative effects. These data support the idea that digital sexual victimization is a new component of IPA polyvictimization, potentially increasing the negative effects experienced by victims of multiple forms of partner aggression.

The discrimination of geoforensic trace material from close proximity locations by organic profiling using HPLC and plant wax marker analysis by GC

There is a need to develop a wider empirical research base to expand the scope for utilising the organic fraction of soil in forensic geoscience, and to demonstrate the capability of the analytical techniques used in forensic geoscience to discriminate samples at close proximity locations. The determination of wax markers from soil samples by GC analysis has been used extensively in court and is known to be effective in discriminating samples from different land use types. A new HPLC method for the analysis of the organic fraction of forensic sediment samples has also been shown recently to add value in conjunction with existing inorganic techniques for the discrimination of samples derived from close proximity locations. This study compares the ability of these two organic techniques to discriminate samples derived from close proximity locations and finds the GC technique to provide good discrimination at this scale, providing quantification of known compounds, whilst the HPLC technique offered a shorter and simpler sample preparation method and provided very good discrimination between groups of samples of different provenance in most cases. The use of both data sets together gave further improved accuracy rates in some cases, suggesting that a combined organic approach can provide added benefits in certain case scenarios and crime reconstruction contexts.

Personality and situational correlates of self-reported reasons for intimate partner violence among women versus men referred for batterers' intervention

This study examines personality and situational correlates of self-reported reasons for intimate partner violence (IPV) among women and men court-ordered to batterers' intervention as IPV offenders. Women endorsed self-defense and men retaliation as their primary reasons for IPV. Both also endorsed emotion dysregulation as a reason for much of their violence. Women's partner violence was largely, but not exclusively, situationally motivated. Women's reasons for violence also related significantly to self-reported borderline personality symptomology. Men's reasons for IPV related primarily to their self-reported antisocial and borderline personality traits, not to situational factors. Thus, the IPV of some women and some men may be considered "characterological," in that it reflects something about the individual's character or personality. Control or domination of one's partner was not a primary reason for violence among women or men, despite the assumption on which many batterer intervention programs are based, that IPV is primarily a power and control tactic. Clinical implications and recommendations for future research are provided.

A proximal change experiment testing two communication exercises with intimate partner violent men

This study tests the immediate impact of two interventions for intimate partner violent (IPV) men in affecting behavioral and emotional change during arguments with their partners. Couples with an abusive male partner (N=100) discussed an area of conflict twice, interrupted by a brief intervention. Men were randomly assigned to receive (a) an editing-out-the-negative skills training, (b) an accepting influence skills training, or (c) a time-out. IPV men in both skills-training conditions showed greater decreases in aggressive feelings than IPV men in the time-out condition based on their self-report and observed affective behavior. Women also reported feeling less aggressive when their husbands were assigned to one of the skills-training conditions as compared to the control (time-out) condition. Results suggest that IPV men can learn to adopt new communication skills and that they do appear to have a positive impact on the emotional tone of their arguments. Clinically, communication skills training may be a useful addition to battering intervention programs, although these skills may need to be taught to both men and women involved in violent relationships.

Intimate partner abuse and PTSD symptomatology: examining mediators and moderators of the abuse-trauma link

Posttraumatic stress disorder (PTSD) has been linked to intimate partner abuse, physiological reactivity, and social support. The authors used structural equation modeling to test social support as a moderator and psychophysiological reactivity and anger as mediators of the relation between abuse and traumatic symptoms among a sample of women reporting psychological abuse, including women reporting both physical violence and no physical violence. Both physical and psychological abuse were related to PTSD symptoms. Whereas physical and psychological abuse were highly correlated, psychological abuse did not predict PTSD symptomatology over and above the effect due to physical assault. Psychophysiological reactivity and anger and fear displayed during an argument with the partner did not mediate the abuse?trauma link. Social support moderated the relation between psychological abuse and PTSD symptomatology.

Perinatal implications of the lower genital tract flora

In a longitudinal study of the microflora of the lower genital tract at three stages in pregnancy and once postnatally, 20 different groups or genera of microorganisms were isolated. No substantial change was demonstrated in the flora as pregnancy progressed, although there was a fall in the rate of isolation of organisms after delivery. Few infants acquired organisms from their mother's lower genital tract. Caucasian mothers colonized by genital ureaplasmas gave birth to infants with a higher mean birth weight for length of gestation than the infants of ureaplasma-negative mothers. There was no correlation between birth weight and maternal genital colonization with ureaplasmas in the infants of Asian mothers. Group B streptococci were recovered from the ano-rectum more frequently than from the posterior vaginal fornix during pregnancy and strains recovered from these sites in individual patients were indistinguishable by serotyping and phage typing, suggesting that the ano-rectum or bowel is the probable source of the organism. Group B streptococci were never recovered from Asian patients (16% of the study population). Sera of women colonized with group B streptococci and cord sera from their infants had higher levels of type-specific IgG antibody than non-colonized controls and their neonates.

In vitro culture of enzymatically isolated chondrons: a possible model for the initiation of osteoarthritis

The aim of this study was to assess whether enzymatically isolated chondrons from normal adult articular cartilage could be used as a model for the onset of osteoarthritis, by comparison with mechanically extracted chondrons from osteoarthritic cartilage. Enzymatically isolated chondrons (EC) were cultured for 4 weeks in alginate beads and agarose gel constructs. Samples were collected at days 1 and 2, and weekly thereafter. Samples were immunolabelled for types II and VI collagen, keratan sulphate and fibronectin and imaged using confocal microscopy. Mechanically extracted chondrons (MC) were isolated, immunohistochemically stained for type VI collagen and examined by confocal microscopy. In culture, EC showed the following characteristics: swelling of the chondron capsule, cell division within the capsule and remodelling of the pericellular microenvironment. This was followed by chondrocyte migration through gaps in the chondron capsule. Four types of cell clusters formed over time in both alginate beads and agarose constructs. Cells within clusters exhibited quite distinct morphologies and also differed in their patterns of matrix deposition. These differences in behaviour may be due to the origin of the chondrocytes in the intact tissue. The behaviour of EC in culture paralleled the range of morphologies observed in MC, which presented as single and double chondrons and large chondron clusters. This preliminary study indicates that EC in culture share similar structural characteristics with MC isolated from osteoarthritic cartilage, confirming that some processes that occur in osteoarthritis, such as pericellular remodelling, take place in EC cultures. The study of EC in culture may therefore provide an additional tool to investigate the mechanisms operating during the initial stages of osteoarthritis. Further investigation of specific osteoarthritic phenotype markers will, however, be required in order to validate the value of this model.

Cytokine profiles in women with different subtypes of major depressive disorder

BACKGROUND

Depression has been associated with activation of the immune system. Some studies have shown increased levels of pro-inflammatory cytokines in patients with major depressive disorder (MDD), but conflicting results also have been described.

METHODS

Forty-six unmedicated women with MDD were classified in subgroups (melancholic vs. non-melancholic; acute vs. chronic; severe vs. moderate, and episodic vs. recurrent presentations) and compared with 41 healthy controls. Evaluations of serum IL-1beta, IL-6, IFN-gamma and cortisol were performed on both groups. Patients were evaluated prior and after antidepressant treatment.

RESULTS

The sub-classification of depression did not predict differences in cytokine levels. Patients currently depressed had similar levels of cytokines and cortisol as healthy controls. After remission of the symptoms, patients with MDD evolved with enhancement of cytokine levels, but no differences were observed in cortisol levels.

LIMITATIONS

In patient treatment, two different classes of antidepressants were applied. The dexamethasone/CRH test was not performed to evaluate the HPA axis.

CONCLUSIONS

Out-patient women diagnosed with MDD exhibited normal levels of both cortisol and cytokines before treatment, yet demonstrated an increase in cytokines after antidepressant treatment. In some patients with MDD, the presence of acute stress due to hospitalization may indeed contribute and justify the usual finding of higher levels in both cortisol and cytokines.

Immunohistochemical Demonstration of Leptin in Pancreatic Islets of Non-Obese Diabetic and CD-1 mice: Co-localization in Glucagon Cells and its Attenuation at the Onset of Diabetes

Leptin is a 16 kD polypeptide hormone produced predominantly by white adipose tissue and exerts profound effects on food intake and energy balance. More recent studies have shown extra sites of leptin production in human and rodent tissues and have ascribed additional roles for the hormone, e.g., in immune and reproductive functions. A role for the hormone has also been implicated in insulin-dependent diabetes mellitus in the non-obese diabetic (NOD) mouse. However, whether leptin originates from islet cells of the mouse is not known. Here dual-label immunohistochemistry was employed to examine leptin expression in islet cells, and its distribution and cellular sources in pancreatic sections of female NOD/Ak and CD-1 mice of various ages. For comparison, leptin immunolabelling was examined in adult pancreatic sections from male NOD/Ak CD-1, Balb/c and FVB/N mice and female severe combined immunodeficient CB. 17 mice. Pancreatic tissues from adult female guinea pig, sheep and cattle and neonatal pigs were also studied. Our results show that in the day 1 NOD and CD-1 mice, leptin immunolabelling was observed in selective glucagon cells within the developing islets while at days 15 and 22, it became more intense and co-incident. This pattern of staining was maintained at days 40, 90, 150 and 250. In the female NOD mouse, leptin was absent in intra-islet immune cells. Its expression was variable in islets from male NOD and CD-1 mice. In spontaneously diabetic female NOD mice and following acceleration of diabetes with cyclophosphamide, despite the persistence of strong immunolabelling for glucagon in the re-distributed alpha cells, leptin expression was either absent, diminished or present in only a proportion of alpha cells. The reduction in leptin labelling was often associated with diabetic islets which had insulitis in association with only a small number of residual beta cells. Leptin expression was absent in guinea pig, ovine, bovine and neonatal porcine islet cells, despite the expression of intensely labelled glucagon cells. The present results demonstrate leptin co-localization in glucagon cells of the mouse islet. Its expression diminishes in the presence of inadequate insulin. Leptin produced within the mouse islet may have bi-directional influences on leptin and insulin regulation and may play local functions in islet development and metabolism.

Fas and Fas ligand immunolocalization in pancreatic islets of NOD mice during spontaneous and cyclophosphamide-accelerated diabetes

During insulin-dependent diabetes mellitus, immune cells which infiltrate pancreatic islets mediate beta cell destruction over a prolonged asymptomatic prediabetic period. The molecular mechanisms of beta cell death in vivo remain unresolved. At least two major molecular processes of destruction have been proposed. One involves the Fas-FasL (Fas-Fas ligand) system and the other, the perforin pathway. Here, dual-label immunohistochemistry was employed to examine the intra-islet expression, distribution and cellular sources of Fas and FasL in the NOD mouse, during spontaneous diabetes (days 21, 40 and 90) and following acceleration of diabetes with cyclophosphamide (days 0, 4, 7, 11 and 14 after cyclophosphamide administration). The expression of the proteins was correlated with advancing disease. FasL was expressed constitutively in most beta cells but not in glucagon or somatostatin cells or islet inflammatory cells and paralleled the loss of insulin immunolabelling with advancing disease. It was also expressed in beta cells of non-diabetes prone CD-1 and C57BL/6 mice from a young age (day 21). Strong immunolabelling for Fas was first observed in extra-islet macrophages and those close to the islet in NOD and non-diabetes-prone mice. During spontaneous and cyclophosphamide diabetes, it was observed in a higher proportion of islet infiltrating macrophages than CD4 and CD8 T cells, concomitant with advancing insulitis. In cyclophosphamide-treated mice, the proportion of Fas-positive intra-islet CD4 and CD8 T cells at day 14 (with and without diabetes) was considerably higher than at days 0, 4, 7 and 11. At days 11 and 14, a proportion of Fas-positive intra-islet macrophages co-expressed interleukin-1beta and inducible nitric oxide synthase. Fas was not detectable in beta cells and other islet endocrine cells during spontaneous and cyclophosphamide induced diabetes. Our results show constitutive expression of FasL in beta cells in the NOD mouse and predominant expression of Fas in intra-islet macrophages and to a lesser extent in T cells prior to diabetes onset. Interleukin-1beta in intra-islet macrophages may induce Fas and inducible nitric oxide synthase expression in an autocrine and paracrine manner and mediate beta cell destruction or even death of some macrophages and T cells. However, other mechanisms of beta cell destruction during spontaneous and cyclophosphamide-accelerated diabetes and independent of Fas-FasL, require examination.

Hydrodynamic shear and collagen receptor density determine the adhesion capacity of S. aureus to collagen

Dynamic bacterial adhesion has recently gained significant attention due to its role in the initiation of infectious diseases. Staphylococcus aureus binding to collagen has been shown to be an important event in the pathogenesis of infection. Staphylococcal strains have exhibited wide variability in their level of collagen binding, which may be a result of the collagen receptor expression level. In this study, the dynamic adhesion to collagen for several S. aureus strains was quantified at physiological wall shear rates in a parallel-plate flow chamber. In addition, the collagen receptor density was quantified for each strain. An existing theoretical framework was used to analyze the dependence of adhesion on receptor density. Intrinsic kinetic adhesion parameters were determined and demonstrated to be strong functions of receptor density for all strains. These results suggest that staphylococcal adhesion to collagen is heavily dependent on the receptor density. Using this analytical approach it is possible to predict the dynamic adhesion of S. aureus to collagen in vitro by only measuring the collagen receptor density.

The differential distribution of acetylated and detyrosinated alpha-tubulin in the microtubular cytoskeleton and primary cilia of hyaline cartilage chondrocytes

The primary cilium is a ubiquitous cytoplasmic organelle of unknown function. Ultrastructural evidence of primary cilia in chondrocytes, and their colocalisation with the Golgi apparatus, has led to speculation that these structures are functionally linked. To investigate the relationship between these organelles, we examined the molecular anatomy of the microtubular cytoskeleton in the chondrocytes of chick embryo sterna. Thick cryosections were immunolabelled with antibodies directed against acetylated alpha-tubulin (C3B9), detyrosinated alpha-tubulin (ID5) and total alpha-tubulin (TAT), and imaged at high magnification using confocal laser scanning microscopy. Transmission electron microscopy confirmed the ultrastructure of the chondrocyte primary cilium and its structural relationship to the Golgi apparatus. Detyrosinated and acetylated alpha-tubulins were concentrated in the centrioles, centrosome and microtubule organising centre adjacent to the nucleus, with total alpha-tubulin distributed throughout the cytoplasm. ID5 stained the primary cilium at an incidence of 1 per cell, its colocalisation with C3B9 identifying the primary cilium as one of the most stable features of the microtubular cytoskeleton. Primary cilia varied from 1 to 4 microm in length, and 3 patterns of projection into the extracellular matrix were identified; (1) full extension and matrix contact, with minor undulations along the length; (2) partial extension and matrix contact, with a range of bending deflections; (3) cilium reclined against the cell surface with minimal matrix contact. Ultrastructural studies identified direct connections between extracellular collagen fibres and the proteins which decorate ciliary microtubules, suggesting a matrix-cilium-Golgi continuum in hyaline chondrocytes. These results strengthen the hypothesis that the primary cilium acts as a 'cellular cybernetic probe' capable of transducing environmental information from the extracellular matrix, communicating this information to the centrosome. and regulating the exocytosis of Golgi-derived secretory vesicles.

Chondrocyte deformation within mechanically and enzymatically extracted chondrons compressed in agarose

Within articular cartilage, the chondron microenvironment will influence chondrocyte behaviour and response to loading. Chondrons were extracted from intact cartilage using either mechanical homogenisation (MC) or enzymatic digestion (EC) and cell and matrix morphology in unstrained and compressed agarose constructs was examined. Isolated chondrocytes (IC) were used for comparison. Immunolocalisation of type VI collagen and keratan sulphate revealed differences in the structure of the pericellular microenvironment such that MC most closely resembled chondrons in situ. The unstrained cell diameters of IC and EC were larger than MC at day 1 and increased significantly over a 7 day culture period. In contrast, cell diameters for MC remained constant. Compression of constructs at day 1 resulted in cell deformation for IC and EC but not MC. The two chondron extraction methods yielded chondrons of differing matrix morphology and associated differences in cell size and cellular response to load. The results indicate that the pericellular microenvironment of MC initially possessed a greater mechanical integrity than that of EC. Although these differences may be reduced with time in culture, characterisation of mechanically isolated chondrons suggests that the stiffness of the chondrons in situ may be greater than previous estimates.

Shear stress prevents fibronectin binding protein-mediated Staphylococcus aureus adhesion to resting endothelial cells

Fibronectin binding proteins (FnBP) on the surface of Staphylococcus aureus have previously been shown to mediate adherence of the organism to resting endothelial cells in static adhesion assays. However, in this study using well-defined flow assays, we demonstrate that physiologic levels of shear stress prevent FnBP-mediated adhesion of S. aureus 8325-4 to resting endothelial cells. This result suggests that mechanical forces present in vivo may influence the ability of staphylococci to bind endothelial cell surfaces.

Quantification of Staphylococcus aureus cell surface adhesins using flow cytometry

The initiation of many infectious diseases involves specific adhesion of bacteria to host tissue proteins and carbohydrates. Staphylococcus aureus is known to bind specifically to several proteins in the extracellular matrix (ECM). We report the quantification of the collagen and fibronectin adhesin densities on the staphylococcal surface using flow cytometry. Our results are in agreement with previous reports on the transcription of the respective genes and demonstrate different patterns of temporal expression for the two adhesins in the strains studied. We demonstrate a convenient technique for quantification of bacterial adhesins that can be used in studies aimed at characterization of bacterial adhesion to ECM components and understanding expression of adhesins during the course of an infection.

Shear stress affects the kinetics of Staphylococcus aureus adhesion to collagen

Staphylococcus aureus is a major human pathogen that has been shown to bind collagen under static conditions. However, many staphylococcal infections are hematogenously acquired and adhesion events may be influenced by shear stress. In this study, we used a dynamic experimental system consisting of a parallel-plate perfusion chamber and phase-contrast video microscope to study the effects of shear stress on the adhesion kinetics of intact S. aureus to collagen surfaces in vitro. The adhesion of S. aureus Phillips to collagen types I, II, and IV was investigated over a physiologically relevant range of wall shear stresses at 37 degrees C. S. aureus PH100, a collagen adhesin-deficient mutant strain, was used as a control strain for the experiments. We found that S. aureus Phillips could adhere to collagens I, II, and IV at wall shear stresses less than 15 dyn/cm(2) and that the kinetics of the adhesion process were wall shear stress-dependent. Similar studies with PH100 demonstrated that these cells are unable to adhere firmly to collagen surfaces. Transient interactions between PH100 and the collagen surfaces were observed at low levels of shear stress suggesting that S. aureus may also interact with collagen by an alternative mechanism that does not lead to firm adhesion.

Mab-3 is a direct tra-1 target gene regulating diverse aspects of C. elegans male sexual development and behavior

Sex determination is controlled by global regulatory genes, such as tra-1 in Caenorhabditis elegans, Sex lethal in Drosophila, or Sry in mammals. How these genes coordinate sexual differentiation throughout the body is a key unanswered question. tra-1 encodes a zinc finger transcription factor, TRA-1A, that regulates, directly or indirectly, all genes required for sexual development. mab-3 (male abnormal 3), acts downstream of tra-1 and is known to be required for sexual differentiation of at least two tissues. mab-3 directly regulates yolk protein transcription in the intestine and specifies male sense organ differentiation in the nervous system. It encodes a transcription factor related to the products of the Drosophila sexual regulator doublesex (dsx), which also regulates yolk protein transcription and male sense-organ differentiation. The similarities between mab-3 and dsx led us to suggest that some aspects of sex determination may be evolutionarily conserved. Here we find that mab-3 is also required for expression of male-specific genes in sensory neurons of the head and tail and for male interaction with hermaphrodites. These roles in male development and behavior suggest further functional similarity to dsx. In male sensory ray differentiation we find that MAB-3 acts synergistically with LIN-32, a neurogenic bHLH transcription factor. Expression of LIN-32 is spatially restricted by the combined action of the Hox gene mab-5 and the hairy homolog lin-22, while MAB-3 is expressed throughout the lateral hypodermis. Finally, we find that mab-3 transcription is directly regulated in the intestine by TRA-1A, providing a molecular link between the global regulatory pathway and terminal sexual differentiation.

Dual-label immunohistochemical study of interleukin-4-and interferon-gamma-expressing cells within the pancreas of the NOD mouse during disease acceleration with cyclophosphamide

Beta cell destruction has been shown to occur when rodent or human islets are exposed in vitro to inflammatory cytokines, such as interleukin-1beta (IL-1beta), tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma). Other cytokines such as interleukin-4 (IL-4) or interleukin-10 (IL-10), when given to NOD mice, prevent insulin-dependent diabetes mellitus (IDDM). In this study, we have employed immunofluorescence histochemistry to study the expression of IFN-gamma and IL-4 in the pancreas of female NOD mice at various time-points (days 0, 4, 7, 11 and at onset of diabetes) following disease acceleration with cyclophosphamide (Cy). Dual-label confocal and light microscopy were employed to determine the precise cellular sources of the two cytokines. IL-4 immunolabelling was observed in a few immune cells at days 0, 4, and 7 within the pancreatic islets but in larger numbers at day 11 and at onset of diabetes. The cytokine was co-localized predominantly in CD4 cells, while only a small minority of CD8 cells and macrophages also expressed IL-4. At days 0, 4, 7 and 11, weak to moderate immunolabelling for IL-4 was also observed in beta cells. In contrast, immunolabelling for IFN-gamma within the islets was not observed until day 11 and this labelling persisted at onset of diabetes. It was immunolocalized in macrophages and to a lesser extent in CD4 cells. Only a few CD8 cells were immunopositive for IFN-gamma. At day 11, a proportion of beta cells showed weak immunolabelling for IFN-gamma. During the study period, immunolabelling for IFN-gamma was also observed in a proportion of endothelial cells located in the intra-islet and exocrine regions of Cy and diluent-treated mice. From day 11 onwards, both the cytokines were observed in some of the peri-vascular regions. Our results demonstrate that during Cy-induced diabetes, there is increasing expression of both IL-4 and IFN-gamma in specific immune cells within the inflamed islets in the late prediabetic stage and at onset of diabetes. Further studies are required to correlate our protein immunohistochemical findings with in situ cytokine gene expression and to determine whether there is a clear Th1 cytokine protein bias at clinical onset of diabetes and immediately preceding it.

Novel experimental study of receptor-mediated bacterial adhesion under the influence of fluid shear

Dynamic adhesion of cells to surfaces is a vital step in a variety of biochemical and physiological phenomena. Bacterial adhesion is responsible not only for problems associated with biofouling and biofilm formation in the biochemical industry but also in the initiation of certain infectious diseases. In this study, we report the effect of critical parameters, such as receptor and ligand densities and shear rate, on receptor-mediated dynamic bacterial adhesion. Adhesion of a pathogenic strain of Staphylococcus aureus to immobilized collagen was studied. The receptor density on the cell surface was varied by harvesting cells at different growth times and was quantified using flow cytometry. Dynamic adhesion experiments were conducted over a range of physiologically relevant shear rates (50 to 1500 s(-1)) using a parallel-plate flow chamber. Video microscopy coupled with digital image processing was employed to quantify adhesion. A semiquantitative comparison between experimental results and theoretical data obtained using a previously proposed mathematical model was also performed. The results suggest that dynamic adhesion is dependent on receptor density and shear rate, but independent of ligand density. This report demonstrates the feasibility of using bacteria to study fundamental aspects of receptor-mediated dynamic adhesion.

Temporal relationship between immune cell influx and the expression of inducible nitric oxide synthase, interleukin-4 and interferon-gamma in pancreatic islets of NOD mice following adoptive transfer of diabetic spleen cells

Beta cell destruction in NOD mice can be accelerated by adoptive transfer of diabetic spleen cells into irradiated adult NOD mice. Here mice receiving diabetic spleen cells were examined at days 0, 7, 14, 21 and at onset of diabetes for the resulting insulitis and the number of intra-islet CD4 and CD8 cells and macrophages. The progression of insulitis and the number of intra-islet CD4 and CD8 cells and macrophages were correlated with the expression and co-localization of inducible nitric oxide synthase, interferon-gamma and interleukin-4 by dual-label light and confocal immunofluorescence microscopy. Diabetes developed in 7/8 mice by 27 days following cell transfer. The insulitis score increased slightly by day 7 but rose sharply at day 14 (p = 0.001) and was maintained until diabetes. The mean number of intra-islet CD4 and CD8 cells and macrophages showed a similar trend to the insulitis scores and were present in almost equal numbers within the islets. Immunolabelling for inducible nitric oxide synthase was observed at day 7 in only some cells of a few islets but increased sharply from day 14. It was restricted to islets with insulitis and was co-localized in selective macrophages. Weak intra-islet interleukin-4 labelling was observed at days 7 and 14 but became more pronounced at day 21 and at onset of diabetes, being present in selective CD4 cells. Intra-islet labelling for interferon-gamma was first observed at day 21, but became more intense at onset of diabetes and was co-localized in a proportion of macrophages. Both cytokines were expressed in islets with advanced insulitis. Interferon-gamma staining was also observed within endothelial cells located in the exocrine pancreas. We conclude that transfer of diabetic spleen cells results in a rapid influx of CD4 and CD8 cells and macrophages within the pancreas of recipient mice. During the period of heightened insulitis, selective immune cells begin to express inducible nitric oxide synthase and the opposing cytokines, interferon-gamma and interleukin-4. Expression of these molecules becomes more pronounced immediately prior to and during the onset of diabetes.

UNC-4/UNC-37-dependent repression of motor neuron-specific genes controls synaptic choice in Caenorhabditis elegans

The UNC-4 homeoprotein and the Groucho-like corepressor UNC-37 specify synaptic choice in the Caenorhabditis elegans motor neuron circuit. In unc-4 mutants, VA motor neurons are miswired with inputs from interneurons normally reserved for their lineal sisters, the VB motor neurons. Here we show that UNC-4 and UNC-37 function together in VA motor neurons to repress VB-specific genes and that this activity depends on physical contact between UNC-37 and a conserved Engrailed-like repressor domain (eh1) in UNC-4. Missense mutations in the UNC-4 eh1 domain disrupt interactions between UNC-4 and UNC-37 and result in the loss of UNC-4-dependent repressor activity in vivo. A compensatory amino acid substitution in UNC-37 suppresses specific unc-4 alleles by restoring physical interactions with UNC-4 as well as UNC-4-dependent repression of VB-specific genes. We propose that repression of VB-specific genes by UNC-4 and UNC-37 is necessary for the creation of wild-type inputs to VA motor neurons. The existence of mammalian homologs of UNC-4 and UNC-37 indicates that a similar mechanism could regulate synaptic choice in the vertebrate spinal cord.

Functional analysis of the Staphylococcus aureus collagen adhesin B domain

The Staphylococcus aureus collagen adhesin (CNA) occurs in at least four forms that differ in the number (one, two, three, or four) of B domains. The B domains contain 187 amino acids and are located between the domains that anchor CNA to the cell envelope and the ligand-binding A domain. To determine whether a B domain is required for functional expression of CNA, we cloned the 2B cna gene from S. aureus strain Phillips and then eliminated both B domains by overlapping PCR. The absence of a B domain did not affect processing of the collagen adhesin to the cell surface or the ability to bind collagen. Based on our recent demonstration that the capsule can mask CNA on the surface of S. aureus cells (A. F. Gillaspy et al., Infect. Immun. 66:3170-3178, 1998), we also investigated the possibility that multiple B domains can extend the ligand-binding A domain outward from the cell surface and thereby overcome the inhibitory effect of the capsule. Specifically, we cloned the naturally occurring 4B CNA variant from S. aureus UAMS-639 and, by successive elimination of B domains, generated 1, 2, and 3B variants that are isogenic with respect to the 4B clone. After introducing each variant into microencapsulated and heavily encapsulated strains of S. aureus and growing cells under conditions known to affect capsule production (e.g., growth on Columbia agar), we correlated capsule production with exposure of CNA on the cell surface and the ability to bind collagen. Under no circumstance was the masking effect of the capsule reduced by the presence of multiple B domains. These results indicate that the B domains do not extend the ligand-binding A domain outward in a fashion that can overcome the inhibition of collagen binding associated with capsule production.

An immunohistochemical study of macrophage influx and the co-localization of inducible nitric oxide synthase in the pancreas of non-obese diabetic (NOD) mice during disease acceleration with cyclophosphamide

Cyclophosphamide has been used to accelerate and synchronize diabetes in non-obese diabetic (NOD) mice. It was injected to 70-day-old female NOD mice and its effect on the progression of insulitis studied at days 0, 4, 7, 11 and at onset of diabetes. Pancreatic sections were also examined for the influx of CD4 and CD8 T cells and macrophages following immunofluorescence staining. The kinetics of macrophage immunoreactive cells in the exocrine and intra-islet areas were also investigated. Light and confocal microscopy were-employed to examine the expression and co-localization of inducible nitric oxide synthase following dual- and triple-label immunofluorescence histochemistry. After cyclophosphamide administration, the severity of insulitis remained similar from days 0 to 4 but began to rise at day 7 and markedly by day 11 and at onset of diabetes. At these two later stages, the insulitis scores were close to 100% while in age-matched control groups the insulitis scores were considerably lower. Immunohistochemical staining showed increasing numbers of CD4 and CD8 T cell subsets and macrophages within the islets and in exocrine, sinusoidal and peri-vascular regions. At onset of diabetes, several islets contained prominent clusters of macrophage immunoreactive cells. Macrophage influx into the islets increased sharply from day 7 (mean number per islet: 119 +/- 54 SEM), peaked at day 11 (mean number per islet: 228 +/- 42), and then declined at onset of diabetes (mean number per islet: 148 +/- 49). Several cells with immunolabelling for inducible nitric oxide synthase were detectable from day 7 onwards until the onset of diabetes. Dual- and triple-label immunohistochemistry showed that a significant proportion of macrophages and only a few beta cells contained the enzyme. Macrophages positive for the enzyme were located as clusters or occasionally contiguously, in the peri-islet and intra-islet areas but rarely in the exocrine region. Islets with minimal distribution of macrophages in the peri-islet areas were not positive for inducible nitric oxide synthase. Beta cells positive for the enzyme were observed in islets with significant macrophage infiltration in locations close to macrophages. The present results show that cyclophosphamide administration to female NOD mice results in a rapid influx of CD4 and CD8 cells and macrophages. The marked up-regulation of inducible nitric oxide synthase in a selective proportion of macrophages, within the islets, immediately preceding and during the onset of diabetes suggests that nitric oxide released by islet macrophages may be an important molecular mediator of beta cell destruction in this accelerated model of insulin-dependent diabetes mellitus.

Inhibition of Staphylococcus aureus adherence to collagen under dynamic conditions

Staphylococcus aureus is the most common etiological agent of bacterial arthritis and acute osteomyelitis and has been shown to bind to type II collagen under static and dynamic conditions. We have previously reported the effect of shear on the adhesion of S. aureus Phillips to collagen and found that this process is shear dependent (Z. Li, M. Höök, J. M. Patti, and J. M. Ross, Ann. Biomed. Eng. 24[Suppl. 1]:S-55). In this study, we used recombinant collagen adhesin fragments as well as polyclonal antibodies generated against adhesin fragments in attempts to inhibit bacterial adhesion. A parallel-plate flow chamber was used in a dynamic adhesion assay, and quantification of adhesion was accomplished by phase contrast video microscopy coupled with digital image processing. We report that both recombinant fragments studied, M19 and M55, and both polyclonal antibodies studied, alpha-M17 and alpha-M55, inhibit adhesion to varying degrees and that these processes are shear dependent. The M55 peptide and alpha-M55 cause much higher levels of inhibition than M19 and alpha-M17, respectively, at all wall shear rates studied. Our results demonstrate the importance of using a dynamic system in the assessment of inhibitory strategies and suggest the possible use of M55 and alpha-M55 in clinical applications to prevent infections caused by S. aureus adhesion to collagen.

Once more onto the couch: consciousness and preconscious defenses in psychoanalysis

Use of the couch in the analytic situation has a unique impact on the consciousness of both participants in the process. The hypnagogic state of the supine analysand and its resonance with the empathic reverie of the unseen analyst are explored, with a focus not on the contents of analysts' countertransferential associations, but on the diverse but converging modes in which they represent their patients' verbal productions. A clinical example is presented to illustrate the interplay between the patient's and the analyst's imaginations, an understanding of which does away with the false dichotomy between defense analysis and empathic responsiveness. The importance of a patient's conscious and preconscious defenses in the here-and-now transference (suppression, "marginalization," disavowal, negation) is also noted, as is the relation of these defenses to unconscious secondary repression.

Identification of distinct metabolic pools of aggrecan and their relationship to type VI collagen in the chondrons of mature bovine articular cartilage explants

The metabolism and distribution of newly synthesized aggrecan present in the extracellular matrix of intact explant cultures of mature articular cartilage was investigated with respect to type VI collagen-stained chondrons. Using biochemical, autoradiographical and novel confocal immunohistochemical techniques it was shown that aggrecan exists as a number of distinct pools that are located within the extracellular matrix of the tissue. The first was identified as a pool of high specific radioactivity, much of which appeared in the medium one day after incubation with radiolabeled sulfate. Of the radiolabeled aggrecan remaining within the extracellular matrix, three pools were differentiated on the basis of time and location within the extracellular matrix. One pool was resident within the pericellular microenvironment associated with the chondron, one migrated into the territorial matrix adjacent to the chondron and one was sequestered long term in the interterritorial matrix. Analysis of the kinetics of loss of radiolabeled aggrecan macromolecules present in the region of matrix defined by the chondron suggests that this pool rapidly turns over and is a precursor to the pools of aggrecan present in the territorial and interterritorial matrix. There were marked differences in the distribution of newly synthesized aggrecan present in these regions of the extracellular matrix in explant cultures maintained with or without fetal calf serum. In the absence of serum, more of the newly synthesized aggrecan moved into the territorial and interterritorial matrix indicating that the presence of serum in the culture medium influenced the tissue distribution of aggrecan. This work indicates that the pericellular microenvironment of the chondron plays an important role in the retention and maturation of aggrecan prior to the sequestration of aggrecan complexes into the functional load bearing matrices of adult articular cartilage.

Loss of glucose transporter-2 precedes insulin loss in the nonobese diabetic and the low-dose streptozotocin mouse models: a comparative immunohistochemical study by light and confocal microscopy

Glucose transporter-2 (glut2) is underexpressed in beta cells of several rodent models of non-insulin-dependent diabetes mellitus (NIDDM). This may also be true for rodent models of insulin-dependent diabetes mellitus (IDDM). The present study examines two murine models of autoimmune IDDM, the nonobese diabetic (NOD) and the low-dose streptozotocin (stz) murine models for changes in the expression of glut2 by double-label light and confocal microscopy during various stages of the disease. The spatial distribution of glut2 cells was also examined in relation to insulin immunoreactive cells and the islet inflammatory cells during these stages. In both the female NOD mouse and the female Swiss mouse without stz treatment, glut2 colocalized with insulin in virtually all the beta cells. In the NOD mouse, islets with moderate to advanced insulitis showed either an absence or considerably reduce expression of glut2 in insulin-containing beta cells. Cells with reduced glut2 expression were usually located adjacent to the region of insulitis. At onset of diabetes, glut2 immunolabeling was reduced despite the preservation of weak insulin immunoreactivity. In Swiss mice treated repeatedly with stz, glut2 labeling began to decline in select Beta cells after the fourth injection in approximately 50% of the islets, despite the lack of insulitis. At this stage expression of glut2 fell in a small number of islets with evidence of early macrophage infiltration. Loss of glut2 became more pronounced in nondiabetic Swiss mice after the fifth injection. At this stage glut2 labeling in the plasma membrane appeared diffuse and variable. At onset of stz-induced diabetes, glut2 expression significantly fell, despite weak immunoreactivity for insulin. This loss was associated with an enhanced influx of both macrophages and T lymphocytes within the islets of diabetes mice. In both the NOD and the low-dose stz mouse models, loss of glut2 thus occurs from an early stage and precedes hyperglycaemia. This loss may be mediated by immune and nonimmune mechanisms.

Fibrillin containing elastic microfibrils support platelet adhesion under dynamic shear conditions

The vascular subendothelium contains macromolecular structures called microfibrils. Type VI collagen is one protein found in microfibrils that supports platelet adhesion and aggregation and we have previously evaluated the roles of platelet receptors and vWf involved in these processes under physiological shear conditions. Here we investigate the ability of fibrillin containing elastic microfibrils to support mural thrombus formation. Our results show that elastic microfibril surfaces support platelet adhesion under low shear conditions at a level similar to collagen VI tetramers. However, the degree of aggregation on the elastic microfibril surface is much higher. Both adhesion and aggregation were shown to be mediated by the GPIIb-IIIa platelet receptor. Elastic microfibrils do not support the formation of mural thrombi under high shear conditions. These results suggest roles for both collagen VI and fibrillin containing elastic microfibrils in modulating the platelet response to blood vessel injury.

The significance of subendothelial von Willebrand factor

von Willebrand factor (vWf) serves to bridge between receptors on the platelet cytoplasmic membrane and the extracellular matrix. In addition to circulating in plasma, vWf is deposited into the extracellular matrix of the subendothelium where it is associated with type VI collagen microfibrils, but not with the elastin-associated microfibrils which are present in the deepest portion of the subendothelium at the zone of the internal elastic lamina. The reaction of platelets to type VI collagen in flow systems is qualitatively different from the shear rate dependent adhesion and aggregation response which is observed with fibrillar type I collagen, exhibiting a response only at low shear rates. The adhesion response to type VI collagen is dependent upon vWf, GP Ib and the GP IIb-IIIa complex. Platelets exposed to purified fibrillin-containing elastin-associated microfibrils adhere and aggregate at low shear rates; this response appears to involve GP IIb-IIIa but not GP Ib. The data are consistent with the hypothesis that type VI collagen is a physiologically relevant binding site for vWf in subendothelium.

Double-label immunofluorescence study of glutamic acid decarboxylase in the fetal and adult ovine pancreas by light and confocal microscopy: evidence for predominant beta-cell coexpression

Glutamic acid decarboxylase (GAD) is present in the central nervous system and in several nonneuronal tissues including the pancreatic islets. There are two isoforms with molecular weights of 65 kDa (GAD65) and 67 kDa (GAD67). The cellular specificity of the two molecular forms of GAD and their levels within the mammalian islets may be species-dependent, being coexpressed in both beta and in non-beta cells. We have examined the ovine pancreas, from the adult and fetal stages of late gestation, for the expression of GAD65 within the islet cells by double-label immunofluorescence light and confocal microscopy. In the adult tissue, GAD65 was colocalized in a majority of the beta cells (> 95%), with only a few glucagon and somatostatin cells (< 5%) showing immunolocalization. During the fetal stages GAD65 also showed a similar predominant beta-cell coexpression. The enzyme was also detected in a few fetal glucagon (< 5%) but not somatostatin cells. In the degenerating large fetal islets, GAD65 was also observed in the majority of the residual beta cells. These results demonstrate that in the ovine pancreas GAD65 is expressed during fetal development and is predominantly beta-cell-restricted. This pattern of expression is maintained during adult life. However, the physiological role of pancreatic GAD and/or its biosynthetic product, gamma-aminobutyric acid, in islet function in the sheep and in other ruminants remains unclear.

General practice training in Uganda. Part 2: Training program and clinical practice

Enabling a developing country to become self-sufficient in health care is a major feat. This two-part article outlines how a general practice training project was established in Uganda to prepare postgraduate students to work in rural hospitals. The first part looked at the setting, personnel, and facilities. Part 2 outlines the curricula and clinical practice.

General practice training in Uganda. Part 1: Setting, personnel, and facilities

Making lasting changes to health care in developing countries is a challenge to industrialized nations. This two-part article outlines how a general practice training project was established in Uganda to prepare postgraduate students to work in rural hospitals. Part 1 covers the setting, those involved, and the facilities available to launch such a project.

The decision to enter a randomized trial of tamoxifen for the prevention of breast cancer in healthy women: an analysis of the tradeoffs

OBJECTIVE

Interest in breast cancer prevention has led to the Breast Cancer Prevention Trial (BCPT), a controversial randomized trial of tamoxifen for women at risk for breast cancer. The goal of our study was to determine whether the potential benefits of enrolling in the randomized trial of prophylactic tamoxifen outweigh the potential risks.

METHODS

We used a decision analytic model based on the available data on tamoxifen treatment benefits in women with breast cancer and extrapolated to its use in healthy women.

RESULTS

For a 50-year-old woman with a breast cancer risk twice that of the average woman her age, the BCPT offers an increase in life expectancy of about 9 days, a gain that is modest compared with other health interventions. For women ages 35 to 60 who meet the minimum risk of breast cancer for trial eligibility, the trial increases life expectancy by about 8 or 9 days. Assumptions about the effect of tamoxifen on the incidence of endometrial and liver cancer and on quality of life associated with tamoxifen did not alter our findings.

CONCLUSIONS

Advocates and opponents of the BCPT should temper their concerns to reflect the modest absolute benefits and harms associated with the trial. Although women at increased risk for breast cancer should be aware of the likely overall benefit associated with entry into the trial, for most women, entry into the BCPT is unlikely to alter substantially their length of life, in either a beneficial or harmful manner.

Molecular Mechanisms of Mural Thrombosis Under Dynamic Flow Conditions

Mural adhesion and aggregation of blood platelets are crucial for hemostasis but in pathological situations can lead to myocardial infarction and stroke. The specific platelet surface receptors employed are determined by the local fluid dynamic conditions and extracellular matrix components exposed at the site of a vascular wound.

Therapeutic computing: teaching therapeutic communications utilizing a videodisc

Effective communication skills for nurses are essential and serve as the interface between patients and health care providers. Yet, teaching communication skills is subject to only limited success. Results vary according to the mix of students, the talent and interest of the instructor, and the availability of teaching time for the topic. The nursing program at Indiana University Kokomo is addressing the needs of nursing students with a multimedia computer system. A videodisc on therapeutic communication was purchased to supply the desired video-based examples. The programming of the computer interface was done by a senior information systems department major. Student attitudes measured after using the system the first year were very good.

Ploidy and Tn-antigen expression in the detection of transitional cell neoplasia in non-tumour-bearing patients

OBJECTIVE

To study the effectiveness of combining DNA ploidy and the blood-group related membrane antigen Tn as bladder tumour markers which have been individually associated with high tumour grade and poor prognosis. In particular to (i) determine whether use of these two markers would improve tumour detection compared with either alone, particularly of high grade disease and (ii) determine whether intermediate rates of marker expression would occur in bladder cancer patients with no current tumour compared with those with a tumour and a control group with benign prostatic hypertrophy.

PATIENTS AND METHODS

A total of 102 patients undergoing cystoscopic monitoring for either benign prostatic hyperplasia (BPH) or for transitional cell carcinoma (TCC) at the Repatriation Hospital and Flinders Medical Centre were included in the study. The patients comprised three study groups, those with BPH (n = 37), with TCC but no tumour present (n = 38) and those with TCC and a tumour present at cystoscopy (n = 27). Exfoliated cells obtained from bladder washings at cystoscopy were double-labelled using a monoclonal antibody to the Tn antigen and a DNA stain, propidium iodide and examined by flow cytometry.

RESULTS

Rates of marker expression in 27 patients with tumours were 30% for Tn antigen, 30% for aneuploidy and 48% for either marker. Marker expression was strongly associated with tumour grade, with no expression at grade 1, 38% (3/8) tumours at grade 2 and 90% (9/10) at grade 3. In patients with a history of bladder tumours but no current tumour, rates were intermediate (30%) compared with patients with current transitional cell carcinoma (42%) and control patients (19%).

CONCLUSION

The use of Tn antigen combined with DNA flow cytometry can increase tumour detection, particularly of high grade, aggressive disease. Gradation of expression of these markers across patient groups at increasing risk of a tumour, with intermediate expression in patients with no current tumour, suggests that marker expression may be detecting a preneoplastic stage of the disease, which is not possible with cytology. Given two parallel disease processes for superficial papillary and for high grade disease with invasive potential, the expression of high grade tumour markers in cells from cystoscopically normal bladders may represent a pre-clinical stage of aggressive disease. The identification of patients at risk of invasive disease using combinations of tumour markers may offer advantages in clinical management, particularly when no tumour is present and therefore no histopathological assessment is made.