The increasing infection of Cryptococcus species and Tricosporon asahii emerged in clinical patients who were immunocompromised. They usually induce lung, skin, brain and systemic infection. Morbidity and mortality of immunocompromised patients are higher than normal healthy people. Cryptococcus neoformans var. grubii ¡]serotype A¡^ infections were reported in clinical cases predominantly and they were isolated from birds¡¦ droppings in large amount. Cryptococcus neoformans var. gattii ¡]serotype B, C¡^ had a natural life in plants, especially Eucalypticus trees. Isolations from other trees were reported increasingly in the tropical and subtropical areas. Comparing to Cryptococcus species, Tricosporon asahii is the normal mycoses of soil. In this study, we performed an environmental investigation concerning Cryptococcus species and Tricosporon asahii in Southern Taiwan. 120 droppings of racing pigeons and 114 samples from Eucalypticus trees were obtained. The results revealed that 30 Cryptococcus neoformans were isolated from racing pigeons¡¦ droppings ¡]25%¡^, as well as 4 Cryptococcus laurentii ¡]3.3%¡^ and 2 Cryptococcus albidus ¡]1.7%¡^. In addition, 25 Tricosporon asahii ( 20.8% ) were isolated from droppings of racing pigeons. But, none of Cryptococcus species or Tricosporon asahii is isolated from Eucalypticus trees ¡]0%¡^. All of Cryptococcus neoformans isolated from pigeons¡¦ droppings were var. grubii ¡]serotype A¡^ and their drug susceptibility tests showed sensitive to Amphotericin B ¡]minimal inhibitory concentration ¡Ø0.25£gg/ml¡^ and Fluconazole ¡]minimal inhibitory concentration 2£gg/ml¡^ and Flucytosine ¡]minimal inhibitory concentration ¡Ø1£gg/ml¡^. To sum up, both Cryptococcus species and Tricosporon asahii were isolated from droppings of racing pigeons in our study, especially Tricosporon asahii in large amount. Opportunistic infection caused by these species should be given more attention to racing pigeons which have close contact with human . Intensive investigation and surveillance should be carried out in the future to provide an information for the control and prevention of diseases.

Streptococcus pneumoniae[italicized everytime] (S. pneumoniae) causes a spectrum of disease severity, and human host factors likely play a role in this variation. One candidate factor is macrophage migration inhibitory factor (MIF), a pro-inflammatory cytokine and upstream regulator of innate immunity. The MIF[italicized when not in parenthesis] promoter contains two functional polymorphisms, a tetranucleotide (CATT) repeat such that MIF expression increases with repeat number from 5-8 and a single nucleotide polymorphism (SNP) leading to a G-to-C transition, which results in increased MIF expression in cell line reporter assays. Emerging data suggest an association between high-expression MIF alleles and inflammatory disease. This study comprised two parts. For the in vitro portion, we hypothesized that peripheral blood monocytic cells (pBMCs) cultured from healthy individuals with low-expressing MIF genotypes (5-CATT alleles or SNP-GG) would have lower MIF content and release than those from individuals with high-expressing MIF genotypes (7-CATT or SNP-C alleles). For the in vivo study, we hypothesized that individuals with low-expressing MIF genotypes would have less severe systemic inflammatory responses than individuals with high-expressing MIF genotypes in response to S. pneumoniae infection. Blood samples and chart findings were collected prospectively at three Connecticut hospitals from 30 inpatients with documented invasive S. pneumoniae infections. Genomic DNA was isolated from host blood, amplified, and genotyped using fragment analysis (CATT repeat) and allelic discrimination (SNP) methods. Fishers exact tests were used to compare genotypes and disease severity. For the in vitro experiments, there were no differences observed in serum MIF levels or MIF content or release from pBMCs based on MIF genotype. In the cohort of patients infected with S. pneumoniae, serum MIF levels among enrolled subjects were significantly higher than the reported normal values, but levels did not vary with genotype or disease severity. The SNP genotype was not correlated with disease severity or occurrence of meningitis. The CATT genotype did not correlate significantly with disease severity or occurrence of meningitis, although there was a trend suggesting an association between the 7-CATT allele and meningitis (p = 0.1188, 8% without meningitis had a 7-CATT allele vs. 40% with meningitis). More patient samples will need to be analyzed in order to definitively elucidate the role of MIF genetics in infection with S. pneumoniae

Thesis (Ph.D.)--Indiana University, 2009. / Title from screen (viewed on December 1, 2009). Department of Anatomy and Cell Biology, Indiana University-Purdue University Indianapolis (IUPUI). Advisor(s): Zao C. Xu, Feng C. Zhou, Charles R. Yang, Theodore R. Cummins. Includes vitae. Includes bibliographical references (leaves 115-135).

Alcohol research has shown that alcohol-related stimuli can disrupt behavioral control and attract more attention in alcohol drinkers. Stimuli typically used in tasks assessing these mechanisms are likely representative of an individual's history. Responses to visual stimuli that no longer closely resemble an individual's history may help shed light on whether these behaviors are due to classical conditioning or processes such as semantic priming. Hypotheses were tested using typical visual stimuli and modified, abstract versions in these tasks. 41 participants were exposed to these stimuli types while using a visual dot probe task. The difference in degree of attentional bias between real and modified stimuli was determined using gaze time. Individuals participated in two versions of the attentional bias-behavioral activation (ABBA) task. Proportion of inhibitory failure differences between versions was examined for the effects of stimuli modification on behavioral control. Results demonstrated that the sample did not exhibit an attentional bias to alcohol. Visual probe results yielded no differences between real and modified stimuli on attentional bias. ABBA performance indicated no differences as a result of image abstraction or stimuli type. Reasons for these findings and comparisons to similar research inquiries using the tasks the current thesis utilized were explored.

Fear conditioning and extinction are central in the cognitive behavioral model of obsessive-compulsive disorder (OCD), which underlies exposure-based cognitive behavioral therapy (CBT). Youth with OCD may have impairments in conditioning and extinction that carries treatment implications. The present study examined these processes using a differential conditioning paradigm. Forty-one youth (19 OCD, 22 community controls) and their parents completed a battery of clinical interviews, rating scales, and a differential conditioning task. Skin conductance response (SCR) served as the primary dependent measure across all three phases of the conditioning procedure (habituation, acquisition, and extinction). During habituation, no meaningful differences were observed between groups. During acquisition, differential fear conditioning was identified across groups evidenced by larger SCRs to the CS+ compared to CS-, with no significant group differences. During extinction, a three-way interaction and follow-up tests revealed youth with OCD failed to exhibit differential fear conditioning during early fear extinction; whereas community controls consistently exhibited differential fear conditioning throughout extinction. Across participants, the number and frequency of OCD symptoms was positively associated with fear acquisition and negatively associated with fear extinction to the conditioned stimulus. OCD symptom severity was negatively associated with differential SCR in early extinction. Youth with OCD exhibit a different pattern of fear extinction relative to community controls that may be accounted for by impaired inhibitory learning in early fear extinction. Findings suggest the potential benefit of augmentative retraining interventions prior to CBT. Therapeutic approaches to utilize inhibitory-learning principles and/or engage developmentally appropriate brain regions during exposures may serve to maximize CBT outcomes.

The striatum is the initial input nuclei of the basal ganglia, and it serves as an integral processing center for action selection and sensorimotor learning. Glutamatergic projections from the cortex and thalamus converge with dense dopaminergic axons from the midbrain to provide the primary inputs to the striatum. Striatal output is then relayed to downstream basal ganglia nuclei by GABAergic medium – sized spiny neurons, which comprise at least 95% of the population of neurons in the striatum. The remaining population of local circuit neurons is dedicated to regulating the activity of spiny projection neurons, and although spiny neurons form a weak lateral inhibitory network among themselves via local axon collaterals, feedforward modulation exerts more powerful control over spiny neuron excitability. Of the striatal interneurons, only one class is not GABAergic. These neurons are cholinergic and correspond to the tonically active neurons (TANs) recorded in vivo, which respond to specific environmental stimuli with a transient depression, or pause, of tonic firing. Striatal cholinergic interneurons account for less than 2 % of the striatal neuronal population, yet their axons form an extensive and complex network that permeates the entire striatum and significantly shapes striatal output by acting at numerous targets via varied receptor types. Indeed, the persistent level of ambient striatal acetylcholine as well as changes to that basal acetylcholine level underlie the major mechanisms of cholinergic signaling in the striatum, however regulation of this system by the local striatal microcircuitry is not well understood. This dissertation finds that activation of intrastriatal cholinergic fibers elicits polysynaptic GABAA inhibitory postsynaptic currents (IPSCs) in cholinergic interneurons recorded in brain slices. Excitation of striatal GABAergic neurons via nicotinic acetylcholine receptors (nAChRs) mediates this polysynaptic inhibition in a manner independent of dopamine. Moreover, activation of a single cholinergic interneuron is capable of eliciting polysynaptic GABAA IPSCs onto itself and nearby cholinergic interneurons. These findings provide an important insight into the striatal microcircuitry controlling cholinergic neuron excitability. / text

Children with traumatic brain injury (TBI) often experience difficulties with inhibitory control (IC), manifest in both neurocognitive function (poor performance on the stop signal task, SST) and behavior (emergence of de novo attention-deficit/hyperactivity disorder, or secondary ADHD, S-ADHD). IC allows for the regulation of thought and action, and interacts with reward to modify behaviour adaptively as environments change. Children with developmental or primary ADHD (P-ADHD) exhibit poor IC and abnormalities when responding to rewards, yet the extent to which S-ADHD is similar to and different from P-ADHD in terms of these behaviours is not well-characterized. The cancellation and restraint versions of the SST were used to examine the effects of rewards on 2 distinct forms of IC in children and adolescents divided into 4 groups (control, TBI, S-ADHD, and P-ADHD). The SST requires participants to respond to a “go signal” and inhibit their responses when encountering a “stop signal”. Rewards improved performance similarly across groups, ages, and cancellation and restraint IC tasks. Adolescents exhibited better IC and faster and less variable response execution relative to children. Significant IC deficits were found in both tasks in the P-ADHD group, with participants with S-ADHD exhibiting intermediate cancellation performance relative to the other groups. Participants with TBI without S-ADHD were not impaired on either task. The relationship between neurocognitive and behavioral IC was examined by comparing multi-informant ratings of IC across groups, and examining the relationship between ratings and IC performance on the SST. Participants in the control and TBI groups were rated within the typical range, and exhibited fewer problems than either of the ADHD groups, who differed from each other (the P-ADHD group was rated as more inattentive than the S-ADHD group). Moderate to high concordance was found between parent and teacher reports, each of which was poorly concordant with self-reports. The P-ADHD and S-ADHD groups were unaware of their own deficits. Poorer IC predicted parent and teacher classification of participants into ADHD subtypes, although IC did not predict rating concordance. Despite similar clinical presentations, S-ADHD and P-ADHD differ in the phenotypic expression of behaviour and manifestation of IC across contexts.

The ability to control one’s behaviour is a fundamental cognitive function subserved by the prefrontal cortex (PFC). Whereas the neural basis of inhibitory control is reasonably well-established, the possible influence of individual differences in personality on cortical activity associated with this ability remains largely unexplored. The present study obtained self-report ratings of Five-Factor Model personality traits from 42 healthy adults while hemodynamic oxygenation in the PFC was recorded during a Go/No-Go task. Results indicated that Neuroticism, Agreeableness and Openness to Experience were associated with attenuated activity in the lateral PFC, a region critical for emotion regulation and behavioural control, whereas Extraversion and Conscientiousness were associated with greater activation in these regions. Activity within the medial PFC, an area linked to task engagement and self-monitoring, shared a positive association with Agreeableness. These findings provide important insights into how neural systems supporting inhibitory control may be affected by individual differences in personality.

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The ability to control one’s behaviour is a fundamental cognitive function subserved by the prefrontal cortex (PFC). Whereas the neural basis of inhibitory control is reasonably well-established, the possible influence of individual differences in personality on cortical activity associated with this ability remains largely unexplored. The present study obtained self-report ratings of Five-Factor Model personality traits from 42 healthy adults while hemodynamic oxygenation in the PFC was recorded during a Go/No-Go task. Results indicated that Neuroticism, Agreeableness and Openness to Experience were associated with attenuated activity in the lateral PFC, a region critical for emotion regulation and behavioural control, whereas Extraversion and Conscientiousness were associated with greater activation in these regions. Activity within the medial PFC, an area linked to task engagement and self-monitoring, shared a positive association with Agreeableness. These findings provide important insights into how neural systems supporting inhibitory control may be affected by individual differences in personality.