Elman topology with sigma-pi units: an application to the modeling of verbal hallucinations in schizophrenia.

The development of neural network models has greatly enhanced the comprehension of cognitive phenomena. Here, we show that models using multiplicative processing of inputs are both powerful and simple to train and understand. We believe they are valuable tools for cognitive explorations. Our model can be viewed as a subclass of networks built on sigma-pi units and we show how to derive the Kronecker product representation from the classical sigma-pi unit. We also show how the connectivity requirements of the Kronecker product can be relaxed considering statistical arguments. We use the multiplicative network to implement what we call an Elman topology, that is, a simple recurrent network (SRN) that supports aspects of language processing. As an application, we model the appearance of hallucinated voices after network damage, and show that we can reproduce results previously obtained with SRNs concerning the pathology of schizophrenia.     

Macrophage-targeted photosensitizer conjugate delivered by intratumoral injection

A conjugate between maleylated albumin and a photosensitizer (PS) shows cell type specific targeting to macrophages via the scavenger receptor. Administration of this conjugate to a tumor-bearing mouse followed by illumination may allow selective destruction of macrophages within tumors. There is accumulating evidence that tumor-associated macrophages contribute to tumor growth, invasiveness, metastasis, and immune suppression. We tested the intravenous (IV) injection of a conjugate between maleylated albumin and chlorin(e6) to BALB/c mice bearing three tumor types with differing proportions of tumor-associated macrophages. The accumulation of PS within the tumors after IV injection and 24 h incubation time was disappointing, and we therefore investigated intratumoral (IT) injection. This gave 20-50 times greater concentrations of PS within the tumor compared to IV injection as determined by tissue extraction. Furthermore the amounts of PS in each tumor type correlated well with the numbers of macrophages both as determined by extraction from bulk tumor and fluorescence quantification and as determined by tissue dissociation to a single cell suspension and two-color flow cytometry with macrophage-specific antibodies. IT injection of nonconjugated PS gave lower tumor accumulation that did not correlate with macrophage content. IT injection of targeted macromolecular delivery systems is an underexplored area and worthy of further study.     

Maintenance of subcutaneous cavities with CO2

Since mechanical retractors in endoscopic plastic surgery cause certain drawbacks, we developed a model in dogs, which, by insufflating CO2 into a subcutaneous cavity, we were able to maintain. We evaluated the magnitude of subcutaneous emphysema and absorption of CO2 by insufflating different pressures and the efficacy of external pressure on the skin with the purpose of limiting the subcutaneous emphysema. Sixteen dogs were divided in 3 groups, A, B, and C. We controlled the pulmonary function by using a volume-cycle ventilator. In all groups, we maintained a subcutaneous cavity by insufflating CO2. Groups A and C were insufflated at 15 mm Hg; group B, at 8 mm Hg. We placed circumferential Esmarch bandages on the thorax of groups B and C to delimit superiorly and inferiorly the surgical area. Arterial blood gas analyses (ABGA) were taken from the femoral artery 60 minutes after intubation, 60 minutes after Esmarch bandage was placed and at the end of the CO2 insufflation. Statistically, results were analyzed by Wilcoxon test. P < 0.05 was considered statistically significant. Group A showed extensive subcutaneous emphysema. Two dogs died. The systemic increase of the CO2 showed a median of 9.6 mm Hg (P < 0.05). In Group B, Esmarch bandages caused increase in CO2, with a median of 1.65 mm Hg (P < 0.028). None of these dogs showed subcutaneous emphysema during the insufflation after CO2 insufflation pressure augmented with a median of 3.7 mm Hg (P < 0.028). In Group C, chest restriction increased CO2 median of 6.1 mm Hg (P < 0.043), and subcutaneous emphysema shown was less extensive than group A. The CO2 increased after insufflation a median of 16 mm Hg (P < 0.043). CONCLUSIONS: Subcutaneous cavities can be maintained open with CO2 insufflation at 8 mm Hg, limiting perfectly the surgical area; as done with Esmarch bandages, it reduces CO2 absorption and makes this procedure safe.     

Wilms tumor in an adult patient: case report

Nephroblastoma or Wilms tumor is the most common renal neoplasia in children, representing 1/5 of the malignant tumors in this group. Nevertheless, the incidence of such tumor in adults is much rarer with less than 250 cases reported. Due to the low-frequency of this pathology in adults there is not a world widely accepted treatment modality. Currently, the therapeutic options derive from the National Wilms Tumor Study (NWTS). We report a new case with the radiological images, histologic findings, outcomes and follow-up.     

Analysis of the role of the PAC1 receptor in neutrophil recruitment, acute-phase response, and nitric oxide production in septic shock

Infections caused by Gram-negative bacteria constitute one of the major causes of septic shock, which results from the inability of the immune system to limit bacterial spread during the ongoing infection. In the last decade, it has been demonstrated that vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP) are two endogenous immunopeptides, which together with three G protein-coupled receptors (VPAC1, VPAC2, and PAC1) exert a significant, therapeutic effect attenuating the deleterious consequences of septic shock by balancing pro- and anti-inflammatory factors. We have recently shown PAC1 receptor involvement in vivo as an anti-inflammatory receptor, at least in part, by attenuating lipopolysaccharide-induced production of proinflammatory interleukin-6. The present study deepens in the protective role of PAC1 receptor in septic shock, elucidating its involvement in the modulation of neutrophil recruitment and in the expression of different molecular sensors such as intercellular adhesion molecule-1, vascular cell adhesion molecule-1, fibrinogen, serum amyloid A, and nitric oxide as important, systemic players of the development of septic shock. Our results, using a mice deficient in PAC1 and a PAC1 antagonist, show that VIP and PACAP as well as the PAC1 receptor are involved in neutrophil recruitment in different target organs, in adhesion molecules expression, and in coagulation-related molecule fibrinogen synthesis. Thus, this study provides some important insights with respect to the involvement of PAC1 into the complexities of sepsis and represents an advantage for the design of more specific drugs complementing standard intensive care therapy in severe sepsis, confirming VIP and PACAP as candidates for multitarget therapy of septic shock.     

Description of Maritrema formicae sp. nov. (Digenea, Microphallidae) parasitic in the kelp gull, Larus dominicanus, from the Patagonian coast, Argentina

Maritrema formicae sp. nov. is described from the Patagonian coast, Argentina, based on adults obtained from the kelp gull, Larus dominicanus. The new species fits with the "eroliae complex" and can be distinguished from other related species mainly in shape and size of body, shape, size, and pattern of distribution of cirrus spines, uterus extension, number and size of eggs, vitellarium in a complete ring in all specimens, and its Neotropical distribution. The new species is sympatric with another species of the genus, Maritrema madrynense, which was recorded in the same host and locality.