The Functional Network Processing Acute Electrical Itch Stimuli in Humans

The posterior insula (pIns) is a major brain region that receives itch-related signals from the periphery and transfers these signals to broad areas in the brain. Previous brain imaging studies have successfully identified brain regions that respond to itch stimuli. However, it is still unknown which brain regions receive and process itch-related signals from the pIns. Addressing this question is important in identifying key functional networks that process itch. Thus, the present study investigated brain regions with significantly increased functional connectivity with the pIns during itch stimuli with 25 healthy subjects by using functional MRI. Electrical itch stimuli was applied to the left wrist. Similar to previous brain imaging studies, many cortical and subcortical areas were activated by itch stimuli. However, not all of these regions showed significant increments of functional connectivity with the pIns during itch stimuli. While the subjects perceived the itch sensation, functional connectivity was significantly increased between the right pIns and the supplementary motor area (SMA), pre-SMA, anterior midcingulate cortex (aMCC), anterior insula (aIns), secondary somatosensory cortex (SII), and basal ganglia (BG), suggesting that this is a key network in processing itch. In particular, intensity of functional connectivity between the pIns and BG was negatively correlated with itch rating. The functional pIns-BG pathway may play an important role in regulation of subjective itch sensation. This study first identified a key brain network to process itch

Efficient depolymerization of polyethylene terephthalate (PET) and polyethylene furanoate by engineered PET hydrolase Cut190

The enzymatic recycling of polyethylene terephthalate (PET) can be a promising approach to tackle the problem of plastic waste. The thermostability and activity of PET-hydrolyzing enzymes are still insufficient for practical application. Pretreatment of PET waste is needed for bio-recycling. Here, we analyzed the degradation of PET films, packages, and bottles using the newly engineered cutinase Cut190. Using gel permeation chromatography and high-performance liquid chromatography, the degradation of PET films by the Cut190 variant was shown to proceed via a repeating two-step hydrolysis process; initial endo-type scission of a surface polymer chain, followed by exo-type hydrolysis to produce mono/bis(2-hydroxyethyl) terephthalate and terephthalate from the ends of fragmented polymer molecules. Amorphous PET powders were degraded more than twofold higher than amorphous PET film with the same weight. Moreover, homogenization of post-consumer PET products, such as packages and bottles, increased their degradability, indicating the importance of surface area for the enzymatic hydrolysis of PET. In addition, it was required to maintain an alkaline pH to enable continuous enzymatic hydrolysis, by increasing the buffer concentration (HEPES, pH 9.0) depending on the level of the acidic products formed. The cationic surfactant dodecyltrimethylammonium chloride promoted PET degradation via adsorption on the PET surface and binding to the anionic surface of the Cut190 variant. The Cut190 variant also hydrolyzed polyethylene furanoate. Using the best performing Cut190 variant (L136F/Q138A/S226P/R228S/D250C-E296C/Q123H/N202H/K305del/L306del/N307del) and amorphous PET powders, more than 90 mM degradation products were obtained in 3 days and approximately 80 mM in 1 day

The Amygdala Network for Processing Itch in Human Brains

Itch is an unpleasant and aversive somatosensory experience. These negative emotions significantly affect mental health in patients with chronic itch; it is therefore important to understand the brain mechanism of negative emotions due to itch. The amygdala is a key hub of networks regulating negative emotions due to itch. However, the exact network involved in this process is unknown. This study used functional magnetic resonance imaging to investigate the amygdala network processing itch in 25 healthy subjects. Brain activity was measured during electrical itch stimuli using functional magnetic resonance imaging. During itch stimuli the amygdala exhibited increased functional connectivity with key brain regions of the serotonergic system responsible for negative emotions (the medial habenula and the median raphe nucleus) and with the memory system, which is responsible for consolidating emotional experiences (the parahippocampus and perirhinal cortex). The serotonergic and memory systems may become therapeutic targets to prevent or reduce diminished mental health commonly seen in chronic itch patients

Trends in Isolated Pelvic Fracture and 30-Day Survival during a Recent 15-Year Period: A Nationwide Study of the Japan Trauma Data Bank

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Neural correlates of perceptual difference between itching and pain: A human fMRI study

It has been wondered why we can discriminate between itching and pain as different sensations. Several researchers have investigated neural mechanisms underlying their perceptual differences, and found that some C fibers and spinothalamic tract neurons had different sensitivity between itching and pain. These findings suggest that such differences in ascending pathways are partly associated with perceptual difference between itching and pain. However, it was still unclear how our brains distinguish itching from pain. Thus, by functional magnetic resonance imaging (fMRI) time series analysis, we investigated the neural substrates of perceptual differences between itching and pain. The anterior cingulate cortex, the anterior insula, the basal ganglia and the pre-supplementary motor area were commonly activated by itching and pain. Neural activity in the posterior cingulate cortex (PCC) and the posterior insula associated with itching was significantly higher than that associated with pain and significantly proportional to itching sensation. Pain, but not itching, induced an activation of the thalamus for several minutes, and neural activity of this brain region significantly correlated to pain sensation. These findings demonstrate that the difference in the sensitivity of PCC, the posterior insula and the thalamus between itching and pain would be responsible for the perceptual difference between these sensations. The previous itching studies did not observe an activation of the secondary somatosensory cortex (S2) by itching. However, we observed that an activation of S2 by pain was not significantly different from that by itching, indicating that S2 was associated with not only pain but also itching

Evaluation of in vivo selective binding of [11C]doxepin to histamine H1 receptors in five animal species

The specific binding of [(11)C]doxepin, which has been used as a radioligand for mapping histamine H(1) receptors in human brain by positron emission tomography, was evaluated in five animal species. In mice the [(11)C]doxepin uptake was reduced by treatment with cold doxepin and two H(1) receptor antagonists, but not with H(2)/H(3) antagonists. The specific binding evaluated with treatment with (+)-chlorpheniramine (H(1) antagonist) was in the range of 10-30% in mouse, rat, rabbit, and monkey, but was not detected in guinea pig