Neuron-microelectrode junction induced by an engineered synapse organizer.

The conventional microelectrodes for recording neuronal activities do not have innate selectivity to cell type, which is one of the critical limitations for the detailed analysis of neuronal circuits. In this study, we engineered a downsized variant of the artificial synapse organizer based on neurexin1ß and a peptide-tag, fabricated gold microelectrodes functionalized with the receptor for the organizer, and performed validation experiments in primary cultured neurons. Successful inductions of synapse-like junctions were detected at the sites of contact between neurons expressing the engineered synapse organizer and functionalized microelectrodes, but not in the negative control experiment in which the electrode functionalization was omitted. Such a molecularly inducible neuron-microelectrode junction could be the basis for the next-generation electrophysiological technique enabling cell type-selective recording.

Analysis of Differences in Single-Joint Movement of Dominant and Non-Dominant Hands for Human-like Robotic Control.

Although several previous studies on laterality of upper limb motor control have reported functional differences, this conclusion has not been agreed upon. It may be conjectured that the inconsistent results were caused because upper limb motor control was observed in multi-joint tasks that could generate different inter-joint motor coordination for each arm. Resolving this, we employed a single wrist joint tracking task to reduce the effect of multi-joint dynamics and examined the differences between the dominant and non-dominant hands in terms of motor control. Specifically, we defined two sections to induce feedback (FB) and feedforward (FF) controls: the first section involved a visible target for FB control, and the other section involved an invisible target for FF control. We examined the differences in the position errors of the tracer and the target. Fourteen healthy participants performed the task. As a result, we found that during FB control, the dominant hand performed better than the non-dominant hand, while we did not observe significant differences in FF control. In other words, in a single-joint movement that is not under the influence of the multi-joint coordination, only FB control showed laterality and not FF control. Furthermore, we confirmed that the dominant hand outperformed the non-dominant hand in terms of responding to situations that required a change in control strategy.

Reverse pH-dependent fluorescence protein visualizes pattern of interfacial proton dynamics during hydrogen evolution reaction.

Reverse pH-dependent fluorescent protein, including dKeima, is a type of fluorescent protein in which the chromophore protonation state depends inversely on external pH. The dependence is maintained even when immobilized at the metal-solution interface. But, interestingly, its responses to the hydrogen evolution reaction (HER) at the interface are not reversed: HER rises the pH of the solution around the cathode, but, highly active HER induces chromophore deprotonation regardless of the reverse pH dependence, reflecting an interface-specific deprotonation effect by HER. Here, we exploit this phenomenon to perform scanning-less, real-time visualization of interfacial proton dynamics during HER at a wide field of view. By using dKeima, the HER-driven deprotonation effect was well discriminated from the solution pH effect. In the electrodes of composite structures with a catalyst, dKeima visualized keen dependence of the proton depletion pattern on the electrode configuration. In addition, propagations of optical signals were observed, which seemingly reflect long-range proton hopping confined to the metal-solution interface. Thus, reverse pH-dependent fluorescent proteins provide a unique tool for spatiotemporal analysis of interfacial proton dynamics, which is expected to contribute to a better understanding of the HER process and ultimately to the safe and efficient production of molecular hydrogen.

Chronic kidney disease in the BCR-ABL1-negative myeloproliferative neoplasm: a single-center retrospective study.

Background/Aims: Renal complications related to BCR-ABL1-negative myeloproliferative neoplasms (MPNs) have not been examined fully in Asian populations. METHODS: We analyzed estimated glomerular filtration rate (eGFR) and its changes with time retrospectively in patients with BCR-ABL1-negative MPN from 2005 to 2015. RESULTS: The prevalence of chronic kidney disease (CKD) was 11% (6.6% having stage 3 and 4.4% having stage 4). In a linear regression analysis of eGFR versus time (years), overall, patients showed increased eGFR (mL/min/1.73 m2) by 0.51 (95% confidence interval [CI], -0.30 to 1.33; p = 0.22). Patients with polycythemia vera (PV), and those treated with hydroxyurea, showed statistically significant increases in eGFR (1.59; 95% CI, 0.28 to 2.90; p = 0.02 in PV; and 1.55; 95% CI, 0.56 to 2.54; p = 0.02 in treatment with hydroxyurea). In total, 17 patients (20.5%) showed rapid loss of eGFR (< -3 mL/min/1.73 m2 per year). This rapid loss in eGFR was associated with a higher incidence of kidney disease (23.5% vs. 6.1%, p = 0.05) and a higher percentage of patients with high neutrophil (> 7.0 × 109 /L) and high monocyte (> 0.7 × 109 /L) counts (76.5% vs. 50%, p = 0.05; 52.9% vs. 28.8%, p = 0.06, respectively). More patients had high serum lactate dehydrogenase (> 500 U/L) levels (52.9% vs. 25.8%, p = 0.03) at diagnosis. Conclusions: CKD is prevalent in patients with BCR-ABL1-negative MPN. Active cytoreductive therapy has the potential to improve kidney function in BCR-ABL1-negative MPN.

A Prospective Multicenter Study Evaluating Secondary Adrenal Suppression After Antiemetic Dexamethasone Therapy in Cancer Patients Receiving Chemotherapy: A Korean South West Oncology Group Study.

BACKGROUND: In a previous pilot study, adrenal suppression was found to be common after antiemetic dexamethasone therapy in cancer patients. The objective of this large prospective multicenter study was to confirm the incidence and factors associated with secondary adrenal suppression related to antiemetic dexamethasone therapy in cancer patients receiving chemotherapy. METHODS: Chemotherapy-naïve patients who were scheduled to receive at least three cycles of highly or moderately emetogenic chemotherapy with dexamethasone as an antiemetic were enrolled. Patients with a suppressed adrenal response before chemotherapy or those administered corticosteroids within 6 months of enrollment in the study were excluded. RESULTS: Between October 2010 and August 2014, 481 patients receiving chemotherapy underwent the rapid adrenocorticotropic hormone (ACTH) stimulation test to assess eligibility; 350 of these patients were included in the final analysis. Fifty-six patients (16.0%) showed a suppressed adrenal response in the rapid ACTH stimulation test at 3 or 6 months after the start of the first chemotherapy. The incidence of adrenal suppression was affected by age, performance status, stage, and use of megestrol acetate in univariate analysis. Multivariate analysis revealed that secondary adrenal suppression associated with antiemetic dexamethasone therapy was significantly associated with megestrol acetate treatment (odds ratio: 3.06; 95% confidence interval: 1.60 to 5.86; p < .001). CONCLUSION: This large prospective study indicates that approximately 15% of cancer patients receiving chemotherapy with a normal adrenal response show suppressed adrenal responses after antiemetic dexamethasone therapy. This result was particularly significant for patients cotreated with megestrol acetate.