Five Amino Acid Residues Responsible for the High Stability of Hydrogenobacter thermophilus Cytochrome c552

Five amino acid residues responsible for extreme stability have been identified in cytochrome c552 (HT c552) from a thermophilic bacterium, Hydrogenobacter thermophilus. The five residues, which are spatially distributed in three regions of HT c552, were replaced with the corresponding residues in the homologous but less stable cytochrome c551 (PA c551) from Pseudomonas aeruginosa. The quintuple HT c552 variant (A7F/M13V/Y34F/Y43E/I78V) showed the same stability against guanidine hydrochloride denaturation as that of PA c551, suggesting that the five residues in HT c552 necessarily and sufficiently contribute to the overall stability. In the three HT c552 variants carrying mutations in each of the three regions, the Y34F/Y43E mutations resulted in the greatest destabilization, by –13.3 kJ mol–1, followed by A7F/M13V (–3.3 kJ mol–1) and then I78V (–1.5 kJ mol–1). The order of destabilization in HT c552 was the same as that of stabilization in PA c551 with reverse mutations such as F34Y/E43Y, F7A/V13M, and V78I (13.4, 10.3, and 0.3 kJ mol–1, respectively). The results of guanidine hydrochloride denaturation were consistent with those of thermal denaturation for the same variants. The present study established a method for reciprocal mutation analysis. The effects of side-chain contacts were experimentally evaluated by swapping the residues between the two homologous proteins that differ in stability. A comparative study of the two proteins was a useful tool for assessing the amino acid contribution to the overall stability.This work was supported in part by grants from Hiroshima University, the Noda Institute for Scientific Research, and the Japanese Ministry of Education, Science and Culture (grants-in-aid for Scientific Research on Priority Areas)

Ganglioside metabolism in a transgenic mouse model of Alzheimer's disease: expression of Chol-1α antigens in the brain

The accumulation of Aβ (amyloid β-protein) is one of the major pathological hallmarks in AD (Alzheimer's disease). Gangliosides, sialic acid-containing glycosphingolipids enriched in the nervous system and frequently used as biomarkers associated with the biochemical pathology of neurological disorders, have been suggested to be involved in the initial aggregation of Aβ. In the present study, we have examined ganglioside metabolism in the brain of a double-Tg (transgenic) mouse model of AD that co-expresses mouse/human chimaeric APP (amyloid precursor protein) with the Swedish mutation and human presenilin-1 with a deletion of exon 9. Although accumulation of Aβ was confirmed in the double-Tg mouse brains and sera, no statistically significant change was detected in the concentration and composition of major ganglio-N-tetraosyl-series gangliosides in the double-Tg brain. Most interestingly, Chol-1α antigens (cholinergic neuron-specific gangliosides), such as GT1aα and GQ1bα, which are minor species in the brain, were found to be increased in the double-Tg mouse brain. We interpret that the occurrence of these gangliosides may represent evidence for generation of cholinergic neurons in the AD brain, as a result of compensatory neurogenesis activated by the presence of Aβ

Hydride-based antiperovskites with soft anionic sublattices as fast alkali ionic conductors

ソフトな陰イオンをもつ逆ペロブスカイト化合物で高速イオン伝導を達成. 京都大学プレスリリース. 2021-01-08.Most solid-state materials are composed of p-block anions, only in recent years the introduction of hydride anions (1s2) in oxides (e.g., SrVO2H, BaTi(O, H)3) has allowed the discovery of various interesting properties. Here we exploit the large polarizability of hydride anions (H–) together with chalcogenide (Ch2–) anions to construct a family of antiperovskites with soft anionic sublattices. The M3HCh antiperovskites (M = Li, Na) adopt the ideal cubic structure except orthorhombic Na3HS, despite the large variation in sizes of M and Ch. This unconventional robustness of cubic phase mainly originates from the large size-flexibility of the H– anion. Theoretical and experimental studies reveal low migration barriers for Li+/Na+ transport and high ionic conductivity, possibly promoted by a soft phonon mode associated with the rotational motion of HM6 octahedra in their cubic forms. Aliovalent substitution to create vacancies has further enhanced ionic conductivities of this series of antiperovskites, resulting in Na2.9H(Se0.9I0.1) achieving a high conductivity of ~1 × 10–4 S/cm (100 °C)

Association between hospital acquired disability and post-discharge mortality in patients after living donor liver transplantation

Background: Hospital-acquired disability (HAD) in patients who undergo living donor liver transplantation (LDLT) is expected to worsen physical functions due to inactivity during hospitalization. The aim of this study was to explore whether a decline in activities of daily living from hospital admission to discharge is associated with prognosis in LDLT patients, who once discharged from a hospital.Methods: We retrospectively examined the relationship between HAD and prognosis in 135 patients who underwent LDLT from June 2008 to June 2018, and discharged from hospital once. HAD was defined as a decline of over 5 points in the Barthel Index as an activity of daily living assessment. Additionally, LDLT patients were classified into four groups: low or high skeletal muscle index (SMI) and HAD or non-HAD. Univariate and multivariate Cox proportional hazard models were used to evaluate the association between HAD and survival.Results: HAD was identified in 47 LDLT patients (34.8%). The HAD group had a significantly higher all-cause mortality than the non-HAD group (log-rank: p < 0.001), and in the HAD/low SMI group, all-cause mortality was highest between the groups (log-rank: p < 0.001). In multivariable analysis, HAD was an independent risk factor for allcause mortality (hazard ratio [HR]: 16.54; P < 0.001) and HAD/low SMI group (HR: 16.82; P = 0.002).Conclusion: HAD was identified as an independent risk factor for all-cause mortality suggesting that it could be a key component in determining prognosis after LDLT. Future larger-scale studies are needed to consider the overall new strategy of perioperative rehabilitation, including enhancement of preoperative physiotherapy programs to improve physical function

Protocol for studying the efficiency of ChemoCalc software in helping patients to understand drug treatment costs for breast cance

Survival of patients with breast cancer can be prolonged by treatment with drugs, particularly new molecular-targeted drugs. However, these agents can be expensive and such treatments can be “an economic burden.” In this ongoing trial, we aim to assess the usefulness of ChemoCalc, a software package for calculating drug costs, to help patients understand the financial outlays. In this multicenter, randomized controlled phase 2 trial, 106 patients with advanced breast cancer will be assigned to either the “ChemoCalc” or “Usual Explanation” group. Treatment using ChemoCalc will be discussed with patients in the ChemoCalc group, whereas standard treatments, without using ChemoCalc, will be discussed with patients in the Usual Explanation group. Subsequently, the participants will decide the treatment and complete a five-grade evaluation questionnaire; those in the Usual Explanation group will receive information about ChemoCalc. Investigators will report if patients subsequently decide to change treatments. The primary endpoint will be the scores of two key questions compared between the groups: “Did you understand the cost of treatment in today\u27s discussion?” and “Do you think the cost of treatment is important in choosing a treatment?“. The secondary endpoints will be to compare discrepancies between treatments recommended by physicians and those selected by patients, the time required for discussion, other questionnaire factors, and the relationship between Comprehensive Score for Financial Toxicity tool and treatment selection. This will be the first randomized controlled trial to assess the efficacy of software to help patients understand drug cost estimates and whether it subsequently affects treatment choice. This study will be conducted according to the CONSORT statement. All participants will sign a written consent form. The study protocol was reviewed and approved by the Clinical Research Review Board of Nagasaki University (19070801). The protocol (version 1) was designed and will be conducted in accordance with the Declaration of Helsinki (1964) and the Ethical Guidelines for Medical and Health Research Involving Human Subjects (2017). The findings will be disseminated through scientific and professional conferences, and in peer-reviewed journals

Observation of Live Ticks (Haemaphysalis flava) by Scanning Electron Microscopy under High Vacuum Pressure

Scanning electron microscopes (SEM), which image sample surfaces by scanning with an electron beam, are widely used for steric observations of resting samples in basic and applied biology. Various conventional methods exist for SEM sample preparation. However, conventional SEM is not a good tool to observe living organisms because of the associated exposure to high vacuum pressure and electron beam radiation. Here we attempted SEM observations of live ticks. During 1.5×10−3 Pa vacuum pressure and electron beam irradiation with accelerated voltages (2–5 kV), many ticks remained alive and moved their legs. After 30-min observation, we removed the ticks from the SEM stage; they could walk actively under atmospheric pressure. When we tested 20 ticks (8 female adults and 12 nymphs), they survived for two days after SEM observation. These results indicate the resistance of ticks against SEM observation. Our second survival test showed that the electron beam, not vacuum conditions, results in tick death. Moreover, we describe the reaction of their legs to electron beam exposure. These findings open the new possibility of SEM observation of living organisms and showed the resistance of living ticks to vacuum condition in SEM. These data also indicate, for the first time, the usefulness of tick as a model system for biology under extreme condition

Incidence of orthostatic hypotension and cardiovascular response to postoperative early mobilization in patients undergoing cardiothoracic and abdominal surgery

Background: In cardiothoracic and abdominal surgery, postoperative complications remain major clinical problems. Early mobilization has been widely practiced and is an important component in preventing complications, including orthostatic hypotension (OH) during postoperative management. We investigated cardiovascular response during early mobilization and the incidence of OH after cardiothoracic and abdominal surgery. Methods: In this prospective observational study, we consecutively analyzed data from 495 patients who underwent elective cardiothoracic and abdominal surgery. We examined the incidence of OH, and the independent risk factors associated with OH during early mobilization after major surgery. Multivariate logistic regression was performed using various characteristics of patients to identify OH-related independent factors. Results: OH was observed in 191 (39%) of 495 patients. The incidence of OH in cardiac, thoracic, and abdominal groups was 39 (33%) of 119, 95 (46%) of 208, and 57 (34%) of 168 patients, respectively. Male sex (OR 1.538; p = 0.03) and epidural anesthesia (OR 2.906; p < 0.001) were independently associated with OH on multivariate analysis. Conclusions: These results demonstrate that approximately 40% patients experience OH during early mobilization aftercardiothoracic and abdominal surgery. Sex was identified as an independent factor for OH during early mobilization after all three types of surgeries, while epidural anesthesia was only identified after thoracic surgery. Therefore, the frequent occurrence of OH during postoperative early mobilization should be recognized