Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0031511 (pheochromocytoma)
 14,622 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

PURPOSE. To investigate the normative data of corneal and anterior segment biometric parameters and their associations in Chinese adults, for use in preoperative assessment for corneal and anterior segment surgery. METHODS. This cross-sectional, population-based study included 750 subjects aged > or =50 years. The subjects underwent an ophthalmic examination including imaging with anterior segment optical coherence tomography (AS-OCT). Dimensions were subsequently measured with the Zhongshan Assessment Program (ZAP). Also measured was posterior corneal arc length (PCAL), a novel parameter defined as the arc distance between scleral spurs on the posterior border of the cornea. Correlations with age, sex, height, weight, body mass index (BMI), refractive sphere and cylinder, and intraocular pressure were also measured. RESULTS. The subjects' mean age was 63.3 +/- 7.9 years and 349 (46.5%) were men. Corneal parameters (mean +/- SD) included PCAL (12.924 +/- 0.544 mm), anterior chamber depth (ACD; 2.684 +/- 0.309 mm), central corneal thickness (562.39 +/- 31.85 microm), anterior chamber curvature (7.35 +/- 0.37 mm), and posterior corneal curvature (6.65 +/- 0.34 mm). A moderate correlation was observed between PCAL and ACD (R = 0.55, P < 0.001) and a poor correlation between PCAL and age, height, weight, and BMI. Multivariate analysis showed a significant association between PCAL and ACD, ACC, PCC, and cylinder (P < 0.05). CONCLUSIONS. In this Chinese population, PCAL was found to correlate moderately with ACD. The data may be useful for corneal and anterior segment procedures such as Descemet's stripping automated endothelial keratoplasty (DSAEK).
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PMID:Biometry of the cornea and anterior chamber in chinese eyes: an anterior segment optical coherence tomography study. 2013 Feb 80

The functional properties of resting brain activity are poorly understood, but have generally been related to self-monitoring and introspective processes. Here we investigated how emotionally positive and negative information differentially influenced subsequent brain activity at rest. We acquired fMRI data in 15 participants during rest periods following fearful, joyful, and neutral movies. Several brain regions were more active during resting than during movie-watching, including posterior/anterior cingulate cortices (PCC, ACC), bilateral insula and inferior parietal lobules (IPL). Functional connectivity at different frequency bands was also assessed using a wavelet correlation approach and small-world network analysis. Resting activity in ACC and insula as well as their coupling were strongly enhanced by preceding emotions, while coupling between ventral-medial prefrontal cortex and amygdala was selectively reduced. These effects were more pronounced after fearful than joyful movies for higher frequency bands. Moreover, the initial suppression of resting activity in ACC and insula after emotional stimuli was followed by a gradual restoration over time. Emotions did not affect IPL average activity but increased its connectivity with other regions. These findings reveal specific neural circuits recruited during the recovery from emotional arousal and highlight the complex functional dynamics of default mode networks in emotionally salient contexts.
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PMID:Impact of transient emotions on functional connectivity during subsequent resting state: a wavelet correlation approach. 2095 2

It has recently become clear that alcohol addiction might be related to a brain dysfunction, in which a genetic background and environmental factors shape brain mechanisms involved with alcohol consumption. Craving, a major component determining relapses in alcohol abuse has been linked to abnormal activity in the orbitofrontal cortex, dorsal anterior cingulated cortex (dACC) and amygdala. We report the results of a patient who underwent rTMS targeting the dACC using a double cone coil in an attempt to suppress very severe intractable alcohol craving. Functional imaging studies consisting of fMRI and resting state EEG were performed before rTMS, after successful rTMS and after unsuccessful rTMS with relapse. Craving was associated with EEG beta activity and connectivity between the dACC and PCC in the patient in comparison to a healthy population, which disappeared after successful rTMS. Cue induced worsening of craving pre-rTMS activated the ACC-vmPFC and PCC on fMRI, as well as the nucleus accumbens area, and lateral frontoparietal areas. The nucleus accumbens, ACC-vmPFC and PCC activation disappeared on fMRI following successful rTMS. Relapse was associated with recurrence of ACC and PCC EEG activity, but in gamma band, in comparison to a healthy population. On fMRI nucleus accumbens, ACC and PCC activation returned to the initial activation pattern. A pathophysiological approach is described to suppress alcohol craving temporarily by rTMS directed at the anterior cingulate. Linking functional imaging changes to craving intensity suggests this approach warrants further exploration.
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PMID:Transient alcohol craving suppression by rTMS of dorsal anterior cingulate: an fMRI and LORETA EEG study. 2145 37

Previous PET and fMRI brain imaging studies targeting neural networks processing itch sensation have used histamine as the sole itch inducer. In contrast with histamine, cowhage-induced itch is mediated via proteinase activated receptors PAR2 and is transmitted through a separate spinothalamic pathway, therefore imaging the brain activation evoked by cowhage could provide further insight into central processing of itch. We report for the first time a functional MRI Arterial Spin Labeling (ASL) study of neuronal processing of itch induced by cowhage, analyzed in contrast with histamine-induced itch. We also explored the brain responses induced by histamine and cowhage combined in a tight sequence. The results of our analyses obtained in a group of 15 healthy volunteers suggested that cowhage and histamine co-activated a core group of brain structures, while also revealing notable differences. Core areas activated by both stimuli were found in the thalamus, primary and secondary somatosensory cortices, posterior parietal cortex, superior and middle temporal cortices, PCC, ACC, precuneus and cuneus. Cowhage induced a notably distinct and more extensive involvement of the insular cortex, claustrum, basal ganglia, putamen, thalamic nuclei and pulvinar. The differences observed between these two itch modalities were investigated to determine the impact of quantitative versus qualitative factors, and correlations between itch intensity and the patterns in brain activation were explored. Our analysis revealed that the most significant differences between cowhage and histamine itch were not affected by stimulus intensity, although a subset of regions displayed activations which were intensity-dependent. The combined application of cowhage and histamine highlighted the role of insula and claustrum in the processing of both itch modalities in the same time. The present results suggest the existence of overlapping but also distinct neuronal networks processing these two different types of itch.
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PMID:A tale of two itches. Common features and notable differences in brain activation evoked by cowhage and histamine induced itch. 2210 Jul 70

Due to broader use of conventional imaging techniques, adrenal tumors are detected with increasing frequency comprising a wide variety of different tumor entities. Despite improved conventional imaging techniques, a significant number of adrenal lesions remain that cannot be easily determined. A particular diagnostic challenge are lesions in patients with known extra-adrenal malignancy because these patients frequently harbor adrenal metastases. Furthermore, adrenal masses with low fat content and no detectable hormone excess are difficult to diagnose properly. Fine needle biopsy is invasive, often unsuccessful, and puts patients at risk, e. g., in cases of pheochromocytoma or adrenal cancer. Noninvasive characterization using radiotracers has therefore been established in recent years. (18)F-FDG PET helps to differentiate benign from malignant lesions. However, it does not distinguish between adrenocortical or nonadrenocortical lesions (e.g., metastases or adrenocortical carcinoma). More recently, enzyme inhibitors have been developed as tracers for adrenal imaging. Metomidate is most widely used. It binds with high specificity and affinity to CYP11B enzymes of the adrenal cortex. As these enzymes are exclusively expressed in adrenocortical cells, uptake of labeled metomidate tracers has been shown to be highly specific for adrenocortical neoplasia. (11)C-metomidate PET and (123)I-iodometomidate SPECT imaging has been introduced into clinical use. Both tracers not only distinguish between adrenocortical and nonadrenocortical lesions but are also able to visualize metastases of adrenocortical carcinoma. The very specific uptake has recently led to first application of (131)I-iodometomidate for radiotherapy in ACC. In conclusion, metomidate-based imaging is an important complementary tool to diagnose adrenal lesions that cannot be determined by other methods.
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PMID:Metomidate-based imaging of adrenal masses. 2212 41

Methods to cognitively distract subjects from pain and experimental paradigms to induce conditioned pain modulation (CPM; formerly termed diffuse noxious inhibitory controls or DNIC) have each highlighted activity changes in closely overlapping cortical areas. This is the first study, to our knowledge, to compare cortical activation changes during these 2 manipulations in the same experimental set-up. Our study sample included thirty healthy young right handed males capable of expressing CPM. We investigated brief consecutive time windows using 32-channel EEG-based sLORETA, to determine dynamic changes in localized cortical potentials evoked by phasic noxious heat stimuli to the left volar forearm. This was performed under visual cognitive distraction tasks and conditioning hot-water pain to the right hand (CPM), both individually and simultaneously. Previously we have shown that for CPM, there is increased activity in frontal cortical regions followed by reduced activation of the somatosensory areas, suggesting a pain inhibitory role for these frontal regions. We now observed that distraction caused a different extent of cortical activation; greater early activation of frontal areas (DLPFC, OFC and caudal ACC at 250-350 ms post-stimulus), yet lesser reduction in the somatosensory cortices, ACC, PCC and SMA after 350 ms post-stimulus, compared to CPM. Both CPM and distraction reduced subjective pain scores to a similar extent. Combining CPM and distraction further reduced pain ratings compared to CPM and distraction alone, supporting the dissimilarity of the mechanisms of pain modulation under these 2 manipulations. The results are discussed in terms of the differential functional roles of the prefrontal cortex.
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PMID:Temporal changes in cortical activation during distraction from pain: a comparative LORETA study with conditioned pain modulation. 2219 9

Intertemporal choice may involve two processing stages: a valuation stage and a choice stage. Decision makers must integrate the various dimensions of an option (e.g., money, time) into a single measure of its subjective value (the valuation stage) and then choose the option that is the most valuable (the choice stage). Although previous studies have implicated that subjective values are represented by a diverse set of brain regions (e.g., vmPFC, VStr, and PCC) in intertemporal choice, it is not yet known which of these regions contain information that directly predicts subsequent choice. To address this question, we measured brain activity using functional MRI while participants performed a simple intertemporal choice task. The results found that participants' decision could be encoded by three specific brain areas (vmPFC, ACC, and PCC) even before they were required to make a choice, while the left posterior insula showed positively active in the choice stage when individuals selected the delayed rewards compared to the immediate rewards. These findings suggest that activation patterns in the vmPFC, ACC, and PCC were able to predict the subsequent choice preference; however, left posterior insula may play an important role for choice preference in the choice stage.
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PMID:The neural predictors of choice preference in intertemporal choice. 2222 35

Psychedelic drugs have a long history of use in healing ceremonies, but despite renewed interest in their therapeutic potential, we continue to know very little about how they work in the brain. Here we used psilocybin, a classic psychedelic found in magic mushrooms, and a task-free functional MRI (fMRI) protocol designed to capture the transition from normal waking consciousness to the psychedelic state. Arterial spin labeling perfusion and blood-oxygen level-dependent (BOLD) fMRI were used to map cerebral blood flow and changes in venous oxygenation before and after intravenous infusions of placebo and psilocybin. Fifteen healthy volunteers were scanned with arterial spin labeling and a separate 15 with BOLD. As predicted, profound changes in consciousness were observed after psilocybin, but surprisingly, only decreases in cerebral blood flow and BOLD signal were seen, and these were maximal in hub regions, such as the thalamus and anterior and posterior cingulate cortex (ACC and PCC). Decreased activity in the ACC/medial prefrontal cortex (mPFC) was a consistent finding and the magnitude of this decrease predicted the intensity of the subjective effects. Based on these results, a seed-based pharmaco-physiological interaction/functional connectivity analysis was performed using a medial prefrontal seed. Psilocybin caused a significant decrease in the positive coupling between the mPFC and PCC. These results strongly imply that the subjective effects of psychedelic drugs are caused by decreased activity and connectivity in the brain's key connector hubs, enabling a state of unconstrained cognition.
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PMID:Neural correlates of the psychedelic state as determined by fMRI studies with psilocybin. 2230 78

The monetary incentive delay task was used to characterize reward anticipation and delivery with concurrently acquired evoked magnetic fields, EEG potentials and EEG/MEG oscillatory responses, obtaining a precise portrayal of their spatiotemporal evolution. In the anticipation phase, differential activity was most prominent over midline electrodes and parieto-occipital sensors. Differences between non-reward- and reward-predicting cues were localized in the cuneus and later in the dorsal PCC, suggesting a modulation by potential reward information during early visual processing, followed by a coarse emotional evaluation of the cues. Oscillatory analysis revealed increased theta power after non-reward cues over fronto-central sites. In the beta range, power decreased with the magnitude of the potential reward and increased with reaction time, probably reflecting the influence of the striatal response to potential reward on the sensorimotor cortex. At reward delivery, negative prediction errors led to a larger mediofrontal negativity. The spatiotemporal evolution of reward processing was modulated by prediction error: whereas differences were located in PCC and putamen in the prediction error comparison, in the case of expected outcomes they were located in PCC, ACC and parahippocampal gyrus. In the oscillatory realm, theta power was largest following rewards and, in the case of non-rewards, was largest when these were unexpected. Higher beta activity following rewards was also observed in both modalities, but MEG additionally showed a significant power decrease for this condition over parieto-occipital sensors. Our results show how visual, limbic and striatal structures are involved in the different stages of reward anticipation and delivery, and how theta and beta oscillations have a prominent role in the processing of these stimuli.
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PMID:Magneto- and electroencephalographic manifestations of reward anticipation and delivery. 2256 Oct 22

Posttraumatic stress disorder (PTSD) has a well-defined set of symptoms that can be elicited during traumatic imagery tasks. For this reason, trauma imagery tasks are often employed in functional neuroimaging studies. Here, coordinate-based meta-analysis (CBM) was used to pool eight studies applying traumatic imagery tasks to identify sites of task-induced activation in 170 PTSD patients and 104 healthy controls. In this way, right anterior cingulate (ACC), right posterior cingulate (PCC), and left precuneus (Pcun) were identified as regions uniquely active in PTSD patients relative to healthy controls. To further characterize these regions, their normal interactions, and their typical functional roles, meta-analytic connectivity modeling (MACM) with behavioral filtering was applied. MACM indicated that the PCC and Pcun regions were frequently co-active and associated with processing of cognitive information, particularly in explicit memory tasks. Emotional processing was particularly associated with co-activity of the ACC and PCC, as mediated by the thalamus. By narrowing the regions of interest to those commonly active across multiple studies (using CBM) and developing a priori hypotheses about directed probabilistic dependencies amongst these regions, this proposed model-when applied in the context of graphical and causal modeling-should improve model fit and thereby increase statistical power for detecting differences between subject groups and between treatments in neuroimaging studies of PTSD.
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PMID:A coordinate-based meta-analytic model of trauma processing in posttraumatic stress disorder. 2293 19


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