Contextual modulation of synchronization to random dots in the cat visual cortex

Synchronization of neuronal activity has been proposed as a binding mechanism for integration of image properties into one coherent percept. In the present study, we investigated the contextual modulation of synchronization to random dot patterns. Coherent motion of random dots evoked well synchronized responses in area 17 of anaesthetized cats when the stimulus was presented in the compound receptive field of recorded sites. Gradually changing the directional coherence of random dots in the surround while maintaining fully coherent motion of the stimulus in the receptive field significantly suppressed synchronization of neuronal activity for some stimulus conditions. However, usually one or two peaks of increased synchronization were found in the surround coherence tuning curves with low (8–12%) and/or moderate (25–50%) coherence in the surround. At the population level, synchronization was significantly depressed with incoherent motion in the receptive field and when both the surround and the receptive field were jointly stimulated with 0% coherence. The intriguing finding was the discovery of two distinct groups of cells with opposite synchronization changes dependent on the presence or absence of significant synchronization in their spontaneous activity. The latter group of neurons showed peaks of increased synchronization with lower surround coherence, thus probably being more sensitive to the direction of the surround motion. Overall, our findings support the notion that binding of stimulus properties can be achieved by synchronized activity of cortical cells. However, our findings go further than the original hypothesis of feature binding by synchrony to show that synchronization of cortical activity may be directly related to the decision making processes, which in turn are related to the threshold of perception of coherent motion.     

Rush desensitization in heparin hypersensitivity: a case report

Among all the known drug intolerances, adverse reactions to heparin are not very common. No desensitization in patients with heparin hypersensitivity has ever been attempted. We report the case of a 55–year-old female patient with mitral stenosis and insufficiency, and tricuspid and aortic insufficiency. The patient underwent heparin treatment, and urticaria occurred with either s.c. calcium heparin or i.v. sodium heparin. Allergy testing (skin tests and patch tests) was negative. A pseudoallergic intolerance was diagnosed. Mitral valve replacement with the extracorporeal circulation method was necessary; therefore, heparin treatment was administered. A heparin rush desensitization together with antihistamine drugs (4 mg clorpheniramine maleate for 3 d) was started: 50 UI (0.5 mg) s.c. sodium heparin were first administered; within 4 d, 5000 UI (50 mg) sodium heparin was administered i.v. with no side-effects. A full-dosage heparin treatment was then administered and heart surgery was easily performed. During the postsurgical course, i.v. sodium heparin was smoothly replaced with s.c. calcium heparin (25000 UI s.c. per day) and with oral anticoagulants (sodium warfarin).     

Age-dependent tendency to become sensitized to other classes of aeroallergens in atopic asthmatic children.

BACKGROUND: Several longitudinal studies report that allergic sensitization increases with age from childhood to adulthood. OBJECTIVE: To evaluate whether an age-dependent tendency to become sensitized to new classes of allergens is present in atopic children, we studied retrospectively the changes in allergic sensitization in 165 asthmatic patients, monosensitized (ie, sensitized to only one class of allergens) in the first survey. METHODS: All the children (18 months to 8 years at enrollment), attended our outpatient clinics twice, at time intervals ranging from 2 to 10 years. On each visit, sensitization to house dust mites, pollens, animal danders, and molds was determined by skin prick test. RESULTS: We found that 43.6% (n = 72) of the patients became polysensitized on the second survey. According to age on first survey, the patients were further divided into two age groups: (1) group 1 = 18 months to < 5 years old (n = 98) and (2) group 2 = 5 to 8 years (n = 67). The transition from monosensitization to polysensitization observed in the entire population was present in both groups: 47 (47.9%) of the 98 children in group 1 and 25 (37.3%) of the 67 children in group 2 showed to be sensitized to more classes of allergens, as compared with first survey. Both in the whole population and in the two age subgroups, the changes in the frequency of monosensitization between the two evaluations were time-dependent (P < .05, each Chi(2)). Finally, to investigate whether monosensitization to a specific class of allergens could favor the development of polysensitization, we evaluated the frequency of polysensitization in the second survey in patients originally monosensitized to house dust mites or to pollens. We found that of the 130 patients originally monosensitized to house dust mites, 59 became polysensitized (45.4%), while of the 28 patients originally monosensitized to pollens, 9 became polysensitized (32.1%) (P > . 1). Similar results were obtained when patients were divided into age groups. CONCLUSION: These data demonstrate that (1) monosensitized children are likely to become polysensitized and (2) house dust mite sensitization and, at a lower degree, pollen sensitization, apparently seem to play a "triggering" role in the development of polysensitization, since a high proportion of children originally monosensitized to house dust mites or to pollens became polysensitized.     

Neutrophil peripheral count and human leukocyte elastase during chronic lithium carbonate therapy

Plasma levels of human polymorphonuclear elastase (PMN-E) are considered a marker of granulocyte activation and can potentially complement the peripheral neutrophil count in laboratory and pathophysiological settings. Neutrophilic leukocytosis is a well known effect of lithium therapy, but there is no information about the concomitant behaviour of PMN-E in these patients. The aim of this study was to evaluate both polymorphonuclear leukocyte count and plasma PMN-E levels in depression patients undergoing chronic lithium therapy. Absolute and differential leukocyte count in venous peripheral blood was determined by an automated method, and PMN-E evaluated by enzyme immunoassay. 39 patients (11 males, 28 females; mean age 43. +/- 6.02) with depression disorders were studied, during lithium carbonate therapy. Neutrophilia (neutrophil count > 7.500x10(9) cells per liter) was found in 7 (18%) patients and an increase in plasma PMN-E levels (PMN-E > 56 microg per liter ) in 6 (15%). No correlations were found between neutrophil count, plasma concentration of PMN-E, plasma level of lithium and duration of therapy. The results show that in these patients, not only the PMN count but also elastase levels can exceed the normal range. The absence of correlation between these two parameters suggests that the state of PMN activation is not linked to their number in peripheral blood.     

Anxiety during pregnancy and fetal attachment after in-vitro fertilization conception

The aim of this study was to compare 70 couples who had conceived by in- vitro fertilization (IVF) with 63 matched controls for the prevalence of anxiety and quality of attachment to the baby during pregnancy. Results for mothers showed no group differences using a global measure of anxiety, the Spielberger State-Trait Anxiety Inventory. However, pregnancy-specific measures revealed significantly higher levels of anxiety in IVF mothers about the survival and normality of their unborn babies, about damage to their babies during childbirth and about separating from their babies after birth. When IVF mothers were differentiated according to the number of treatment cycles, more differences in anxiety level were revealed, with most increases occurring in mothers who had experienced two or more treatment cycles. IVF fathers did not differ from controls on the global anxiety measure. No data on pregnancy-specific anxiety were available for fathers. Neither IVF mothers nor IVF fathers differed from controls on measures of attachment to the baby during pregnancy. Results are discussed in the context of the need for researchers to employ differentiated and issue-specific measures to identify concerns that may be unique to IVF couples. Clinical implications regarding the need for psychological support during pregnancy are also discussed.      

Behavioral patterns proceeding from liver thermoreceptors

Subdiaphragmatic denervated, liver heated rats eat as much and as long as subdiaphragmatic denervated, non-heated rats. This points to vagus and/or splanchnic nerve afferentation from hepatic thermoreceptors. Left abdomen heated rats eat and drink as much as left abdomen non-heated rats. Since however they show some different behavior patterns, the intervention of other nerve fibers other than vagal and/or splanchnic fibers should be acknowledged in order to account for the different behavior pattern.     

Modulation of HLA-DR antigen and ICAM-1 molecule expression on airway epithelial cells by sodium nedocromil.

OBJECTIVE: To test in vitro and in vivo the hypothesis that sodium nedocromil could modulate the expression of surface molecules on airway epithelial cells. METHODS: Human bronchial epithelial cells, obtained from surgically resected bronchi, were cultured and stimulated with recombinant IFN-gamma in the presence of sodium nedocromil. The intensity of the expression of surface molecules HLA-DR and ICAM-1 molecules on bronchial epithelial cells in vitro, was quantified by specific antibody staining and flow-cytometry analysis. Furthermore, we studied the effect of the drug on airway inflammation in vivo and on allergic rhinitis patients sensitized to house dust mites. Nasal epithelial cells were collected by brushing, at baseline and 2 to 3 weeks after treatment with sodium nedocromil. The expression of HLA-DR and ICAM-1 molecules was measured by flow-cytometry, and the proportions of neutrophils and eosinophils "contaminating" the epithelial cells evaluated by light microscopy examination of nasal brushings. RESULTS: The enhanced HLA-DR and ICAM-1 expression, induced by IFN-gamma, was effectively downregulated, in a dose-dependent manner, by sodium nedocromil. At all the concentrations tested (10(-9) to 10(-4) M), the inhibitory activity of the drug was stronger on HLA-DR than on ICAM-1 expression (P<.05, all comparisons). As compared with healthy subjects, patients with allergic rhinitis had a higher expression of HLA-DR (P<.05) but not of ICAM-1 molecules (P>.05) on nasal epithelial cells, and higher proportions of nasal eosinophils (P<.05). Treatment with sodium nedocromil downregulated the expression of HLA-DR (P<.05), but not of ICAM-1 (P>.05), and induced a mild, but not statistically significant, decrease of nasal eosinophilia (P>.05). CONCLUSION: These data demonstrate that the antiinflammatory activity of sodium nedocromil may include modulation of surface molecule expression on airway epithelial cells.     

Modulation of the constitutive or cytokine-induced bronchial epithelial cell functions in vitro by fluticasone propionate

When exposed to proinflammatory mediators, human bronchial epithelial cells (HBECs) upregulate the 'constitutive' adhesion molecule expression and cytokine/chemokine release. We tested whether and to what extent the inhibitory effect of fluticasone propionate on HBECs could involve the 'constitutive' and 'cytokine-induced' proinflammatory functions. Stimulation of the HBECs with interleukin (IL)-4 plus tumour necrosis factor (TNF)-alpha was more effective in upregulating intercellular adhesion molecule (ICAM)-1 ( approximately 2.2-fold increase) than vascular adhesion molecule (VCAM)-1 ( approximately 1.6-fold increase) expression (P<0.05) and in increasing the release of 'regulated on activation normal T cell expressed' (RANTES, 5.7-fold increase) than of IL-8 (3.5-fold increase) and granulocyte macrophage-colony stimulating factor (GM-CSF, 2.8-fold increase), (P<0.01). Fluticasone propionate, at the two concentrations tested (10 and 100 nM), was more effective in inhibiting the 'IL-4 plus TNF-alpha-induced' ICAM-1 expression than VCAM-1 expression (P<0.05) and in downregulating RANTES than IL-8 or GM-CSF secretion (P<0.05). The degree of inhibition demonstrated by fluticasone propionate appeared to be related to the degree of cell activation. In addition, for both adhesion molecules, the effect of fluticasone propionate at both concentrations tested appeared to be related to a complete inhibition of 'IL-4 plus TNF-alpha-induced' expression with no involvement of the 'constitutive' expression. Slightly different results were observed for cytokine/chemokine release. Indeed, evaluating RANTES, a complete inhibition of the 'IL-4 plus TNF-alpha-induced' release with a partial inhibition also of the 'constitutive' release at both concentrations of the drug tested was found, whereas for GM-CSF and IL-8, only a partial inhibition of the 'IL-4 plus TNF-alpha-induced' release in the presence of fluticasone propionate 10 and 100 nM. Thus, HBECs can constitutively or upon activation express adhesion molecules and secrete proinflammatory proteins at various levels and the different ability of fluticasone propionate to modulate the HBEC functions appears to be mostly related to the different inhibition of the various 'IL-4 plus TNF-alpha-induced' responses.     

Multifunctional microcapsules for pancreatic islet cell entrapment: design,preparation and in vitro characterization

Great advances in cell transplantation have been made, including the recent, remarkable success in pancreatic islet transplantation for the treatment of type 1 diabetes mellitus. Unfortunately, the transplanted cells are very susceptible to oxidative stress that cause severe damage to either allo- or xenogeneic islets upon graft in diabetic patients. Consequently, the transplanted islet functional life span is significantly shortened. The aim of this study was to examine the possible effects of antioxidants on in vitro cultured adult rat islets, and to evaluate the effects of a prolonged-release formulation, in form of cellulose acetate (CA) microspheres, on Vitamin D(3) activity. Isolated rat islets, both free and entrapped in microspheres were treated with Vitamin D(3). The effects of the vitamin were studied at 3, 6 and 9 days of in vitro cell culture. According to insulin secretory patterns, treatment with Vitamin D(3) of both free and CA entrapped microspheres, increased the insulin output as compared to untreated controls. Such positive effects were confirmed under islet static incubation with glucose at day 6. These results suggest that pancreatic islets can be advantageously treated with anti-oxidising vitamins before implantation, and speculatively, with the help of special delivery systems, throughout the islet cell life span, in the post-transplant time period.