Pain, autonomic dysfunction, and course of disease in Guillain-Barré Syndrome

The Guillain-Barré syndrome (GBS) is an immune-mediated polyneuropathy. Until now, GBS remains a descripti ve diagnosis for which there are no specific diagnostic tests. The combinati on of rapidly progressive symmetrical weakness in arms and legs with or without sensory disturbances, hypo- or areflexia, in the absence of a cerebrospinal fluid (CSF) cellular reacti on, remains the hallmark for the clinical diagnosis of GBS. In GBS, there is a broad spectrum of clinical symptoms and severity in the acute phase. During the subsequent course of disease, the presence and severity of residual symptoms is highly variable. In most treatment studies only severely aff ected pati ents (those being unable to walk without assistance; GBS disability scale grade have been included. Because progressive paralysis is the most striking and alarming symptom of GBS, most att enti on generally is given to the rapid progression and severity of weakness in the acute phase. There are however some underexposed but important issues in GBS like residual fi ndings in parti cular in pati ents which limited weakness (mildly aff ected pati ents), a fl uctuati ng course aft er initi al improvement (treatment related fl uctuati ons (TRF)), the transiti on to chronic infl ammatory demyelinati ng polyneuropathy (CIDP) and the frequency and nature of pain and autonomic dysfuncti on that have been studied limited so far. These issues have formed the basis of the studies described in this thesis. The following cases illustrate the importance of these underexposed issues

Feature integration in natural language concepts

Two experiments measured the joint influence of three key sets of semantic features on the frequency with which artifacts (Experiment 1) or plants and creatures (Experiment 2) were categorized in familiar categories. For artifacts, current function outweighed both originally intended function and current appearance. For biological kinds, appearance and behavior, an inner biological function, and appearance and behavior of offspring all had similarly strong effects on categorization. The data were analyzed to determine whether an independent cue model or an interactive model best accounted for how the effects of the three feature sets combined. Feature integration was found to be additive for artifacts but interactive for biological kinds. In keeping with this, membership in contrasting artifact categories tended to be superadditive, indicating overlapping categories, whereas for biological kinds, it was subadditive, indicating conceptual gaps between categories. It is argued that the results underline a key domain difference between artifact and biological concepts

Portuguese category norms for children

This study presents Portuguese category norms for children of three different age groups: preschoolers (3- to 4-year-olds), second graders (7- to 8-year-olds), and preadolescents (11- to 12-year-olds). Three hundred Portuguese children (100 in each group) completed an exemplar-generation task. Preschoolers generated exemplars for 13 categories, second graders generated exemplars for 17 categories, and preadolescents generated exemplars for 21 categories. For each group, responses within each category were organized according to frequency of production in order to derive exemplar-production norms for sets of tested categories. The results also included information about the number of responses and exemplars, idiosyncratic and inappropriate responses, and commonality and diversity indexes for all the categories. A comparison of these children’s norms with the Portuguese adult norms was also presented. The full set of norms may be downloaded from www.psychonomic.org/archive

Supervised versus unsupervised categorization: Two sides of the same coin?

Supervised and unsupervised categorization have been studied in separate research traditions. A handful of studies have attempted to explore a possible convergence between the two. The present research builds on these studies, by comparing the unsupervised categorization results of Pothos et al. (submitted; 2008) with the results from two procedures of supervised categorization. In two experiments, we tested 375 participants with nine different stimulus sets, and examined the relation between ease of learning of a classification, memory for a classification, and spontaneous preference for a classification. After taking into account the role of the number of category labels (clusters) in supervised learning, we found the three variables to be closely associated with each other. Our results provide encouragement for researchers seeking unified theoretical explanations for supervised and unsupervised categorization, but raise a range of challenging theoretical questions

Combining conventional therapy with immunotherapy: A risky business?

Because of the failure of immunotherapy as single agent in a number of cancers, current clinical trials are focusing on combining immunotherapy with other therapies. The most frequently chosen combination for immunotherapy is chemotherapy. However, almost no preclinical data on this combination is available. Some studies even showed a dismal effect of combining chemotherapy with immunotherapy. Taken into account that each of the therapies chosen in a combination will influence the cancer cells but also immune effector cells as well as immunosuppressive cells, and that these three partners will also interact with each other, launching a combination to the patient without proper immune monitoring and preclinical evidence might be devastating

Role of the Arabidopsis PIN6 auxin transporter in auxin homeostasis and auxin-mediated development

Plant-specific PIN-formed (PIN) efflux transporters for the plant hormone auxin are required for tissue-specific directional auxin transport and cellular auxin homeostasis. The Arabidopsis PIN protein family has been shown to play important roles in developmental processes such as embryogenesis, organogenesis, vascular tissue differentiation, root meristem patterning and tropic growth. Here we analyzed roles of the less characterised Arabidopsis PIN6 auxin transporter. PIN6 is auxin-inducible and is expressed during multiple auxin–regulated developmental processes. Loss of pin6 function interfered with primary root growth and lateral root development. Misexpression of PIN6 affected auxin transport and interfered with auxin homeostasis in other growth processes such as shoot apical dominance, lateral root primordia development, adventitious root formation, root hair outgrowth and root waving. These changes in auxin-regulated growth correlated with a reduction in total auxin transport as well as with an altered activity of DR5-GUS auxin response reporter. Overall, the data indicate that PIN6 regulates auxin homeostasis during plant development.Christopher I. Cazzonelli, Marleen Vanstraelen, Sibu Simon, Kuide Yin, Ashley Carron-Arthur, Nazia Nisar, Gauri Tarle, Abby J. Cuttriss¤, Iain R. Searle, Eva Benkova, Ulrike Mathesius, Josette Masle, Jiří Friml, Barry J. Pogso