Dynamics of neuronal sensitivity in visual cortex and local feature discrimination

A striking aspect of natural scenes is that image features such as line orientation are strongly correlated at neighboring spatial locations but not at distant locations. Thus, during the viewing of a scene, eye movements are often accompanied by a change in the orientation structure of the image. How does this behavior influence the discrimination of local features and their encoding by visual cortical neurons? Here we examined the perceived changes in orientation induced by brief exposure to oriented image patterns in monkeys and humans, and then used reverse correlation to investigate dynamic changes in neuronal sensitivity in the primary visual cortex (V1) of behaving monkeys. Whereas brief adaptation to an oriented grating impaired identification of nearby orientations by broadening orientation selectivity and changing the preferred orientation of individual V1 neurons, it actually enhanced the identification of orthogonal orientations by sharpening neuronal selectivity. Hence, successive exposure to image patches of dissimilar spatial structure enhances both the ability to discriminate local features and the encoding of these features by V1 neurons.     

Procalcitonin Levels in Patients with Complete and Incomplete Kawasaki Disease

Incomplete Kawasaki disease (iKD) is considered to be a less complete form of Kawasaki disease (cKD), and several differences in the laboratory presentations of iKD and cKD have been noted. We investigated serum procalcitonin levels in patients with iKD, cKD, and other febrile diseases (a control group). Seventy-seven patients with cKD, 24 with iKD, and 41 controls admitted to our hospital from November 2009 to November 2011 were enrolled in the present study. We obtained four measurements of serum procalcitonin levels and those of other inflammatory markers from each patient. Samples were taken for analysis on the day of diagnosis (thus before treatment commenced; D0) and 2 (D2), 14 (D14), and 56 days (D56) after intravenous immunoglobulin infusion. We obtained control group data at D0. The mean D0 serum procalcitonin levels of cKD patients (0.71 ± 1.36 ng/mL) and controls (0.67 ± 1.06 ng/mL) were significantly higher than those of iKD patients (0.26 ± 0.26 ng/mL) (P = 0.014 and P = 0.041, resp.). No significant difference in mean procalcitonin level was evident among groups at any subsequent time. In conclusion, the serum procalcitonin level of patients with acute-stage cKD was significantly higher than that of iKD patients.     

Lessons for the laboratory from a general practitioner survey.

AIMS: To assess the current performance of the clinical biochemistry service provided to general practitioners, with particular attention to result turnround times, and to identify and improvements required. METHODS: Postal questionnaire survey of general practitioners in the London Borough of Tower Hamlets who used the clinical biochemistry laboratory of the Royal London Hospital. A flow analysis study of turnround times for general practitioner samples was also performed. RESULTS: Responses to the questionnaire showed that although 82% of general practitioners thought the current quality of service provided was better than fair, the actual turnround times achieved were longer than the acceptable times required. There was also a strong demand (> 66% of responders) for additional information-such as highlighting of abnormal results-to be provided with results. There was wide variability between practitioners in their use of the laboratory (from none to > 800 requests per year), with no apparent correlation to practice size. Of the repertoire of tests requested, a surprisingly high percentage (14.3%) were for thyroid function. Flow analysis of turnround times for thyroid function tests showed that problems lay not with the time taken for analysis (only 7.8% of the total turnround time) but with the pre- and postanalytical phases, that is, the sample collection and results delivery service. CONCLUSIONS: Increasing the proportion of health care delivered in the primary care sector will inevitably increase the requirement for pathology services. Improvements in the specimen collection and results delivery service to general practitioners are needed to meet their expectations. It remains to be determined whether increased investment in these aspects of laboratory service would result in improved patient care in the primary sector.     

Effects of graft pooling of foetal rat and mouse tissue and immunosuppression in the 6-hydroxydopamine rat model of Parkinson’s disease

 We employed intracerebral co-transplantation of foetal xenogeneic striatal mouse tissue and allogeneic rat substantia nigra into the adult rat brain to elucidate the effects of xenogeneic mouse graft on the function and survival of an allogeneic rat graft in 6-hydroxydopamine lesioned Sprague-Dawley rats. Foetal mouse striatum (STR) and rat substantia nigra (VM) were transplanted as non-pooled separate deposits or a pooled cell suspension with or without cyclosporin A (Cy A). Immunosuppressed recipients of pooled rat and mouse co-grafts showed a significantly better compensation of amphetamine-induced rotational behaviour compared with non-immunosuppressed animals with pooled rat and mouse co-grafts 3 and 6 weeks post-grafting.Tyrosine hydroxylase (TH) immunohistochemistry revealed a non-significant reduction in survival in pooled (1806.3±367.5 cells) rat and mouse co-transplants without immunosuppression compared with immunosuppressed pooled (3383.3±732.7 cells) animals with allo- and xenogeneic tissue and controls (3506.4±839.3 cells). Graft volumes were significantly reduced in pooled transplants without immunosuppression (0.1±0.026 mm³; ANOVA post-hoc SchefféF-test, P<0.0001) compared with immunosuppressed recipients (0.7±0.1 mm³) and controls (0.6±0.1 mm³). In non-pooled allo- and xenogeneic grafts without immunosuppression the survival rate of the TH-immunoreactive cells and graft volumes were reduced (2359.3±479.5 cells; 0.2±0.043 mm³) compared with immunosuppressed animals (2927.3±946.6 cells; 0.6±0.2 mm³) and controls (2701.1±693.8 cells; 0.3±0.1 mm³) without reaching a level of significance. Rejection of mouse tissue was observed in all non-immunosuppressed recipients. In summary: (i) continued immunosuppression yielded significant beneficial effects on function and beneficial effects on survival of pooled grafts with an immunogenetic disparity; (ii) the rejection of a xenogeneic graft component may compromise survival and function of other, allogeneic graft components; and (iii) transplantation of non-pooled allo- and xenogeneic tissues may result in a better survival of the graft compared with pooled cell suspensions. Received: 25 March 1996 / Accepted: 1 December 1996     

THE THEORY OF THE BASIC ASSUMPTION OF INCOHESION: AGGREGATION/MASSIFICATION OR (BA) I:A/M

Presented in honour of Dr Estela Welldon as a friend and colleague, and in acknowledgement of her contributions to forensic psychotherapy and group analysis for people who suffer from extreme anxieties associated with confused sex and gender identifications and choices, sado-masochism and criminality, this article integrates Bionian and Foulkesian perspectives in group analysis by conceptualizing a fourth basic assumption in the unconscious life of social systems. The basic assumption of Incohesion: Aggregation/Massification or (ba) I:A/M is derived from a relational rather than an instinctual metapsychology, and assumes that helplessness and the fear of annihilation precede the emergence of envy, thus emphasizing the importance of traumatogenic processes. Traumatized people with crustacean and amoeboid defences/protections against the fear of annihilation are likely to personify aggregation and massification processes, respectively. This theory can be applied in the group treatments of our most disturbed patients, and in understanding the dynamics of traumatized social systems, ranging from families to organizations and even societies.     

Etoposide protein binding in cancer patients

The protein binding of etoposide was studied in vivo in 36 cancer patients receiving etoposide therapy. Free etoposide was separated from plasma using an ultrafiltration method and the etoposide concentrations (free and total) were measured by high-performance liquid chromatography (HPLC). Considerable interpatient variation in the protein binding of etoposide was observed. The protein binding of etoposide varied from 80% to 97% (mean, 93%). Univariate analysis showed a significant inverse correlation between the free fraction of etoposide and serum albumin (r=–0.74), daily dose (r=–0.37) and age (r=–0.34). Multivariate analysis demonstrated that serum albumin and age were independent predictors of the etoposide free fraction. Serum bilirubin showed no correlation with etoposide protein binding. There is wide variation in etoposide protein binding in cancer patients, which is mostly dependent on serum albumin concentration.