Effects of light intensity and pattern contrast on the ability of the land crab, Cardisoma guanhumi, to separate optic flow-field components

Using a novel suite of computer-generated visual stimuli that mimicked components of optic flow, the visual responses of the tropical land crab, Cardisoma guanhumi, were investigated. We show that crabs are normally successful in distinguishing the rotational and translational components of the optic flow field, showing strong optokinetic responses to the former but not the latter. This ability was not dependent on the orientation of the crab, occurring both in "forwards-walking" and "sideways-walking" configurations. However, under conditions of low overall light intensity and/or low object/background contrast, the separation mechanism shows partial failure causing the crab to generate compensatory eye movements to translation, particularly in response to low-frequency (low-velocity) stimuli. Using this discovery, we then tested the ability of crabs to separate rotational and translational components in a combined rotation/translation flow field under different conditions. We demonstrate that, while crabs can successfully separate such a combined flow field under normal circumstances, showing compensatory eye movements only to the rotational component, they are unable to make this separation under conditions of low overall light intensity and low object/background contrast. Here, the responses to both flow-field components show summation when they are in phase, but, surprisingly, there is little reduction in the amplitude of responses to rotation when the translational component is in antiphase. Our results demonstrate that the crab's visual system finds separation of flow-field components a harder task than detection of movement, since the former shows partial failure at light intensities and/or object/background contrasts at which movement of the world around the crab is still generating high-gain optokinetic responses.     

Y-26763: ATP-sensitive K+ channel activation and the inhibition of insulin release from human pancreatic beta-cells

The effect of Y-26763 [(-)-(3S,4R)-4-(N-acetyl-N-hydroxyamino)-6-cyano-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-3-ol], a novel ATP-sensitive K(+) (K(ATP)) channel activator, was tested on insulin secretion from human pancreatic islets in vitro. Y-26763 was able to inhibit both glucose- and tolbutamide-induced insulin secretion from islets as assessed by radioimmunoassay. The mechanism for inhibition of insulin secretion was characterised using patch clamp electrophysiology on dispersed human pancreatic beta-cells which express K(ATP) channels comprised of Kir6.2 and SUR1, and the NES2Y human beta-cell line, transfected with Kir6.2DeltaC26. Y-26763 activated K(ATP) channels in a reversible manner with a similar activity to diazoxide. This required the presence of hydrolysable nucleotides and appeared to be mediated by interaction of Y-26763 with SUR1 since: (a) tolbutamide was able to reverse the actions of Y-26763 and (b) Y-26763 failed to activate Kir6.2DeltaC26 in the absence of SUR1. We conclude that Y-26763-induced inhibition of insulin release is dependent upon the activation of K(ATP) channels in human beta-cells.     

Strong association of a functional polymorphism in the monocyte chemoattractant protein 1 promoter gene with lupus nephritis

OBJECTIVE: Lupus nephritis (LN) is a major contributor to morbidity and mortality in patients with systemic lupus erythematosus (SLE). There is evidence that polymorphisms in the genes of inflammatory mediators may predispose to the development of LN in patients with SLE. In this study, we examined the role of a functional monocyte chemoattractant protein 1 (MCP-1) polymorphism in SLE and LN. METHODS: DNA and paired urine and serum samples were obtained from 134 SLE patients (> or =4 American College of Rheumatology criteria for SLE; 49 with and 85 without LN) and 118 controls. MCP-1 genomic variants were detected by polymerase chain reaction followed by restriction enzyme-fragment analysis. Urinary and serum MCP-1 levels and MCP-1 production by peripheral blood macrophages were measured by enzyme-linked immunosorbent assay. RESULTS: The A/A genotype was more common in controls than in SLE patients (P = 0.0002), whereas both the A/G (P = 0.009) and G/G (P = 0.0212) genotypes were more frequent in SLE patients. The A/A genotype was observed in only 23% of the patients with LN compared with 58% of those without LN (P < 0.0001). MCP-1 production by peripheral blood mononuclear cells from patients with the A/G and G/G phenotypes was markedly higher than the production by cells from patients with the A/A genotype. Urinary levels of MCP-1 were significantly higher in patients with LN. CONCLUSION: These results suggest that an A/G or G/G genotype may predispose to the development of SLE and further indicate that SLE patients with these genotypes may be at higher risk of developing LN. Moreover, measurement of urinary levels of MCP-1 may be a useful tool for the detection and management of LN.     

Therapie des Dekubitus beim älteren Patienten

The treatment of pressure sores in elderly patients requires careful documentation and a comprehensive treatment plan, which takes into account the patient's overall situation. The treatment has to be evidence based. At the moment only three recommendations can be based on two or more prospective, randomized clinical studies: to use a dressing to maintain a moist environment at the wound/dressing interface, to reduce the risk of infection and enhance wound healing by hand washing, wound cleansing and debridement and to institute a systemic antibiotic treatment for patients with advancing cellulitis, sepsis and osteomyelitis. For other treatment options such as topical negative pressure, maggot therapy, electromagnetic therapy, therapeutic ultrasound or growth factors, the data at present are not sufficient to support general use in pressure sore treatment.     

Virusexantheme

Zusammenfassung Die häufigste Ursache exanthematischer Exantheme sind Virusinfektionen, die direkt oder über die Reaktion des Immunsystems Hautveränderungen auslösen. Für viele distinkte parainfektiöse Krankheitsbilder sind mehrere Viren aus ganz unterschiedlichen Gruppen befähigt, ein bestimmtes Exanthem auszulösen. Als dominierende Erreger exanthematischer Erkrankungen gelten Nicht-Polioenteroviren, respiratorische Viren, Epstein-Barr-, HHV-6- und HHV-7-Viren sowie Parvovirus B19. In vielen Fällen manifestieren sich Exantheme makulös oder makulopapulös in disseminierter Verteilung. Einige Exanthemerkrankungen weisen typische Prädilektionsstellen auf. Neben dem klinischen Bild sind Anamnese, Beachtung des Allgemeinzustandes und der Jahreszeit sowie die körperliche Untersuchung diagnoseweisend. Bei Unklarheiten und für wissenschaftliche Fragestellungen sichern Blutuntersuchungen, Abstriche und Histologie die Diagnose. Die Kenntnis der Exanthemerkrankungen, die zumeist harmlos verlaufen, ist zur Abgrenzung lebensbedrohlicher Erkrankungen wichtig. Im Folgenden werden exanthematische Viruserkrankungen in Abhängigkeit vom Hauptmanifestationsalter dargestellt.     

Gesundheitliche Eigenverantwortung

Because of the persistent shortage of health care resources, scientists and politicians are discussing ways to increase the patients' personal responsibility for their own health. Based on a philosophical analysis of the concept of responsibility, this article tries to assess strengths and limits of a personal responsibility for health, illustrated by the prevention of cutaneous melanoma. On the one hand, individuals bear prospective responsibility for their health status by adopting a healthy lifestyle and participating in prevention programs. On the other hand, individuals can--retrospectively--be held responsible for those conditions that result from the voluntary choice of health risks. Considering the tremendous practical and ethical problems associated with retrospective responsibility, prevention and public health policies should emphasize prospective personal responsibility for health.     

Thrombophilia interpretation in childhood stroke: a cautionary tale

Several authors have reported a link between childhood stroke and inherited thrombophilia in recent years. The impact of such a relationship on management and outcome is yet to be determined, as is the potential cost-benefit ratio associated with the performance of thrombophilic screening in children presenting with ischemic stroke. We present a case that highlights the need for clinical and radiologic examinations to remain the definitive criteria used to diagnose stroke in children. The diagnosis should not be influenced by the finding of a thrombophilic marker.     

The determinants and effect of shared care on patient outcomes and psychiatric admissions

OBJECTIVE: The aim of this study was to determine the factors associated with receipt of different levels of shared care, and the effect of shared care on patient outcomes. METHOD: A total of 349 patients with severe mental illness were selected from general practice lists. Patient functioning was assessed using standardised questionnaires, and GPs completed a questionnaire about patients' shared care arrangements at baseline (response-rate 79%). Patients were followed up at 12 months. RESULTS: Receipt of high shared care was associated with greater patient satisfaction with services and social functioning at baseline (p < 0.005). Patients receiving high shared care showed greater improvements in SF-12 mental health scores at follow-up compared to low shared care groups (p = 0.02). This effect was abolished after adjustment for age, sex and psychiatric diagnosis. CONCLUSION: Receipt of high shared care was not associated with demographic or clinical characteristics. High shared care had limited value for patients in terms of improved clinical, social or general health functioning over one year.     

Realistic spatial sampling for MEG beamformer images

The spatial resolution achievable using magnetoencephalography (MEG) beamformer techniques is inhomogeneous across the brain and is related directly to the amplitude of the underlying electrical sources [Barnes and Hillebrand, Hum Brain Mapp 2003;18:1-12; Gross et al., Proc Natl Acad Sci USA 2001;98:694-699; Van Veen et al., IEEE Trans Biomed Eng 1997;44:867-860; Vrba and Robinson, Proc 12th Int Conf Biomagn 2001]. We set out to examine what an adequate level of spatial sampling of the brain volume is in a realistic situation, and what implications these inhomogeneities have for region-of-interest analysis. As a basis for these calculations, we used a simple retinotopic mapping experiment where stimuli were 17-Hz reversing gratings presented in either left or right visual hemifield. Beamformer weights were calculated based on the covariance of the MEG data in a 0-80 Hz bandwidth. We then estimated volumetric full-width half-maximum (FWHM) maps at a range of sampling levels. We show that approximately 10% of the 1 mm cubic voxels in the occipital volume have a FWHM smoothness of <5 mm, and 80% <10 mm in three subjects. This was despite relatively low mean signal-to-noise ratios (SNR) values of 1.5. We demonstrate how visualization of these FWHM maps can be used to avoid some of the pitfalls implicit in beamformer region-of-interest analysis.     

Preliminary outcomes from an integrated mental health primary care team

The effects of establishing a multidisciplinary mental health primary care team in a Veterans Affairs internal medicine primary care clinic were evaluated. The multidisciplinary team worked in collaboration with primary care providers to evaluate and treat their patients, who had a wide variety of psychiatric disorders, in the primary care clinic. In the first year of operation preliminary outcomes indicated that the rate of referrals to specialty mental health care dropped from 38 percent to 14 percent. The mean number of appointments with the team for evaluation and stabilization was 2.5. These outcomes suggest that a multidisciplinary mental health primary care team can rapidly evaluate and stabilize patients with a wide range of psychiatric disorders, reduce the number of referrals to specialty mental health care, and improve collaborative care.