Neocortical layer 4 as a pluripotent function linearizer

A highly effective kernel-based strategy used in machine learning is to transform the input space into a new "feature" space where nonlinear problems become linear and more readily solvable with efficient linear techniques. We propose that a similar "problem-linearization" strategy is used by the neocortical input layer 4 to reduce the difficulty of learning nonlinear relations between the afferent inputs to a cortical column and its to-be-learned upper layer outputs. The key to this strategy is the presence of broadly tuned feed-forward inhibition in layer 4: it turns local layer 4 domains into functional analogs of radial basis function networks, which are known for their universal function approximation capabilities. With the use of a computational model of layer 4 with feed-forward inhibition and Hebbian afferent connections, self-organized on natural images to closely match structural and functional properties of layer 4 of the cat primary visual cortex, we show that such layer-4-like networks have a strong intrinsic tendency to perform input transforms that automatically linearize a broad repertoire of potential nonlinear functions over the afferent inputs. This capacity for pluripotent function linearization, which is highly robust to variations in network parameters, suggests that layer 4 might contribute importantly to sensory information processing as a pluripotent function linearizer, performing such a transform of afferent inputs to a cortical column that makes it possible for neurons in the upper layers of the column to learn and perform their complex functions using primarily linear operations.     

Apoptosis of cord blood neutrophils and their response to colony-stimulating factors

Neutrophil production and functions are immature in newborns. Although neutrophil kinetics during neonatal period have been widely studied, little is known about the effect of apoptosis on these defects. In this study, we examine the apoptosis of neonatal neutrophils and the effects of colony-stimulating factors (CSF) on this process. The study was performed using three different methodologies (morphological analysis, surface Fas expression, and mitochondrial 7A6 antigen expression) and the results were compared with adult controls. Neonatal neutrophils more rapidly underwent apoptosis in comparison to adult neutrophils. The above-mentioned three different methods gave similar results. Granulocyte-CSF (G-CSF) and granulocyte-macrophage CSF (GM-CSF) decreased the apoptosis of neutrophils in newborns and adults. This effect was significantly more pronounced in adults than newborns in morphological analysis. Increased apoptosis may contribute to qualitative and quantitative defects of neutrophils during neonatal period and may be an explanation for the proneness of newborn to develop neutropenia during systemic infections.     

The effect of cetirizine on IFN-gamma and IL-10 production in children with allergic rhinitis

Cetirizine, one of the most commonly used antihistamines for the treatment of allergic diseases, possesses some anti-inflammatory properties. Despite its common use, the effect of cetirizine on the production of cytokines from peripheral blood mononuclear cells (PBMCs) needs further clarification. The aim of this study was to investigate whether cetirizine changes interleukin (IL)-10, (IF)-gamma and IL-4 production from PBMCs in children with allergic rhinitis. Thirteen children with allergic rhinitis sensitized to house dust mite (HDM) were treated with cetirizine for four weeks. Blood samples were drawn just prior to the treatment, on the last day of the treatment and two weeks following the cessation of treatment The cytokine production from PBMCs was tested in the presence or absence of HDM allergen and measured by ELISA assay. An augmentation in IL-10 production was observed in PBMCs at the 4th week of cetirizine treatment (p<0.05). Furthermore, a significant increase in IFN-gamma production was observed following the therapy. IL-4 release did not change at all time points tested. In addition, IFN-gamma/IL-4 ratio increased following cetirizine treatment. Cetirizine induced a shift in the human Th1/Th2 cytokine balance toward a Th1 type response by increasing IFN-gamma production and augmenting suppressor cytokine release (IL-10). We concluded that apart from its known antihistaminic properties, cetirizine may modulate allergic inflammation while the patients are on regular treatment schedules.     

Clinical importance of circulating and cellular expression levels of Fas and Fas ligand in pediatric patients with lymphoproliferative malignancies

Objectives of this study were to determine the extend of soluble Fas (sFas) and soluble FasL (sFasL) at the time of diagnosis and to evaluate its prognostic relevance under chemotherapy in childhood lymphoproliferative malignancies. The authors measured the circulating sFas and sFasL by ELISA in 25 children with newly diagnosed either ALL or NHL, as well as their expression of Fas and FasL at the time of diagnosis and remission. They did not observe any statistically significant difference between the patient group and age-matched healthy controls for sFas levels, whereas sFasL concentration in study population at the time of diagnosis was significantly higher than that in control subjects (1.05 ± 1.46 vs. 0.36 ± 0.18 ng/mL, p = .024). At remission the authors observed a significant decrease in the sFasL levels of all patients whose sFasL concentrations were above the minimal detectable level at the time of diagnosis (p = .008). sFasL and Fas/FasL immunohistochemical staining did not have an effect on survival. sFasL may be a marker in monitoring complete remission in children with LPM.     

EFFECT OF SHORT-COURSE, HIGH-DOSE STEROID THERAPY IN A CHILD WITH MYELODYSPLASTIC SYNDROME

High-dose methylprednisolone (HDMP) has been shown to induce differentiation of myeloid leukemic cells with a remarkable antileukemic effect in children with various subtypes of acute myeloblastic leukemia (AML). Here the beneficial effect of short-course HDMP therapy in a child with myelodysplastic syndrome (MDS) is reported. Oral methylprednisolone sodium succinate (Prednol-L) was administered at a single daily dose of 30 mg/kg for 5 days to a 4-year-old girl with refractory anemia with excess of blasts and hypocellular bone marrow before the initiation of chemotherapy. In addition to dramatic clinical improvement, the patient's white blood cell count increased from 2.3 ×10 9 /L to 5.0 ×10 9 /L, and peripheral blood blast cells disappeared 4 days after HDMP treatment. Repeated bone marrow aspirate 1 week after the initiation of HDMP disclosed increased cellularity with no blasts. Furthermore, short-course HDMP treatment stimulated the increase in the number of peripheral blood lymphocytes and CD3 + , CD4 + , CD8 + , CD19 + , CD34 + , and NK cells. Results obtained with HDMP from the previous studies and the present case suggest that high-dose methylprednisoloneis a promising agent in the treatment of MDS and it is recommended as an initial treatment especially for MDS children with hypocellular bone marrow at presentation.     

Intradiploic cavernous hemangioma of the skull in a child: a case report

INTRODUCTION: Intradiploic cavernous hemangioma of the skull is seen rarely. Intradiploic cavernous hemangiomas arise from the intrinsic vasculature of the bone and generally picks up at the fourth and fifth decades. DISCUSSION AND CONCLUSION: In this report, we present a 16-year-old child who was admitted with a swelling lesion in the right parietal bone and diagnosed as cavernous hemangioma after total extirpation.