Protonation State of a Key Histidine Ligand in the Iron-Quinone Complex of Photosystem II as Revealed by Light-Induced ATR-FTIR Spectroscopy.

The iron-quinone complex in photosystem II (PSII) consists of the two plastoquinone electron acceptors, QA and QB, and a non-heme iron connecting them. It has been suggested that nearby histidine residues play important roles in the electron and proton transfer reactions of the iron-quinone complex in PSII. In this study, we investigated the protonation/deprotonation reaction of D1-H215, which bridges the non-heme iron and QB, using attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Flash-induced Fe2+/Fe3+ ATR-FTIR difference spectra were measured with PSII membranes in the pH range of 5.0-7.5. In the CN stretching region of histidine, the intensity of a negative peak at 1094 cm-1, which was assigned to the deprotonated anion form of D1-H215, increased as the pH increased. Singular-value decomposition analysis provided a component due to deprotonation of D1-H215 with a pKa of ∼5.5 in the Fe3+ state, whereas no component of histidine deprotonation was resolved in the Fe2+ state. This observation supports the previous proposal that D1-H215 is responsible for the proton release upon Fe2+ oxidation [Berthomieu, C., and Hienerwadel, R. (2001) Biochemistry 40, 4044-4052]. The pH dependence of the 13C isotope-edited bands of the bicarbonate ligand to the non-heme iron further showed that deprotonation of bicarbonate to carbonate does not take place at pH <8 in the Fe2+ or Fe3+ state. These results suggest that the putative mechanism of proton transfer to QBH- through D1-H215 and bicarbonate around Fe2+ functions throughout the physiological pH range.

Current Ventilator and Oxygen Management during General Anesthesia: A Multicenter, Cross-sectional Observational Study.

BACKGROUND: Intraoperative oxygen management is poorly understood. It was hypothesized that potentially preventable hyperoxemia and substantial oxygen exposure would be common during general anesthesia. METHODS: A multicenter, cross-sectional study was conducted to describe current ventilator management, particularly oxygen management, during general anesthesia in Japan. All adult patients (16 yr old or older) who received general anesthesia over 5 consecutive days in 2015 at 43 participating hospitals were identified. Ventilator settings and vital signs were collected 1 h after the induction of general anesthesia. We determined the prevalence of potentially preventable hyperoxemia (oxygen saturation measured by pulse oximetry of more than 98%, despite fractional inspired oxygen tension of more than 0.21) and the risk factors for potentially substantial oxygen exposure (fractional inspired oxygen tension of more than 0.5, despite oxygen saturation measured by pulse oximetry of more than 92%). RESULTS: A total of 1,786 patients were found eligible, and 1,498 completed the study. Fractional inspired oxygen tension was between 0.31 and 0.6 in 1,385 patients (92%), whereas it was less than or equal to 0.3 in very few patients (1%). Most patients (83%) were exposed to potentially preventable hyperoxemia, and 32% had potentially substantial oxygen exposure. In multivariable analysis, old age, emergency surgery, and one-lung ventilation were independently associated with increased potentially substantial oxygen exposure, whereas use of volume control ventilation and high positive end-expiratory pressure levels were associated with decreased potentially substantial oxygen exposure. One-lung ventilation was particularly a strong risk factor for potentially substantial oxygen exposure (adjusted odds ratio, 13.35; 95% CI, 7.24 to 24.60). CONCLUSIONS: Potentially preventable hyperoxemia and substantial oxygen exposure are common during general anesthesia, especially during one-lung ventilation. Future research should explore the safety and feasibility of a more conservative approach for intraoperative oxygen therapy.

Effectiveness of Polyglycolic Acid Sheet Covering and Platelet-Rich Plasma after Video-Assisted Thoracic Surgery for Spontaneous Pneumothorax.

Background Video-assisted thoracic surgery (VATS) is widely used for the treatment of spontaneous pneumothorax, and the recurrence rate is high. The goal of the study was to examine the use of polyglycolic acid (PGA) sheets, together with platelet-rich plasma (PRP) from autologous blood for the prevention of postoperative recurrence of spontaneous pneumothorax. Materials and Methods We performed a retrospective study of 65 patients who underwent VATS for spontaneous pneumothorax from March 2008 to November 2011. The patients were divided into groups: without reinforcement (Group A, n = 33) and with reinforcement of the visceral pleura around the staple lines with the PGA sheet and PRP (Group B, n = 32). The postoperative follow-up period was 18 months. Results Chest tubes were used for 3.4 and 3.1 days in Groups A and B, respectively, with no significant difference between the groups. However, the recurrence rate (18.2%; 6 cases) in Group A was significantly higher than that in Group B (p = 0.02). The recurrence rates in patients younger than 25 years in Group A and Group B were 26.1 and 0.0%, respectively (p = 0.03). In Group A, the mean age with recurrence (18.3 years old) was significantly lower than the mean age without recurrence (p = 0.03). Conclusion These results suggest that the use of PGA sheets and PRP might be effective for the prevention of postoperative recurrence of spontaneous pneumothorax.

Photodynamic Therapy (PDT) with Chemotherapy for Advanced Lung Cancer with Airway Stenosis.

Intractable advanced lung cancer can be treated palliatively with photodynamic therapy (PDT) combined with chemotherapy to remove central and peripheral (lobar or segmental bronchi) bronchial stenosis and obstruction. We present data for 12 (eight men, four women) consecutive patients with 13 advanced non-small cell lung carcinomas in whom curative operations were contraindicated, who underwent PDT combined with chemotherapy for local control of the intraluminal lesions. The mean age was 73.3 years (range, 58-80 years), and the stages of cancer were IIA-IV. The median stenosis rates before treatment, one week post-treatment, and one month post-treatment were 60% (range, 30%-100%), 15% (range, 15%-99%), and 15% (range 15%-60%), respectively. The mean and median survival times were 9.3 and 5.9 months, respectively. The overall 1-year survival rate was 30.0%. No PDT-related morbidity or mortality occurred. In this single-institution study, all patients experienced improved symptoms and quality of life at one week after treatment; furthermore, an objective response was evidenced by the substantial increase in the openings of the bronchial lumen and prevention of obstructive pneumonia. Therefore, PDT with chemotherapy was useful and safe for the treatment of bronchial obstruction.

Current status of delirium assessment tools in the intensive care unit: a prospective multicenter observational survey.

Delirium is a critical challenge in the intensive care unit (ICU) or high care unit (HCU) setting and is associated with poor outcomes. There is not much literature on how many patients in this setting are assessed for delirium and what tools are used. This study investigated the status of delirium assessment tools of patients in the ICU/HCU. We conducted a multicenter prospective observational study among 20 institutions. Data for patients who were admitted to and discharged from the ICU/HCU during a 1-month study period were collected from each institution using a survey sheet. The primary outcome was the usage rate of delirium assessment tools on an institution- and patient-basis. Secondary outcomes were the delirium prevalence assessed by each institution's assessment tool, comparison of delirium prevalence between delirium assessment tools, delirium prevalence at the end of ICH/HCU stay, and the relationship between potential factors related to delirium and the development of delirium. Result showed that 95% of institutions used the Intensive Care Delirium Screening Checklist (ICDSC) or the Confusion Assessment Method for the ICU (CAM-ICU) to assess delirium in their ICU/HCU, and the remaining one used another assessment scale. The usage rate (at least once during the ICU/HCU stay) of the ICDSC and the CAM-ICU among individual patients were 64.5% and 25.1%, and only 8.2% of enrolled patients were not assessed by any delirium assessment tool. The prevalence of delirium during ICU/HCU stay was 17.9%, and the prevalence of delirium at the end of the ICU/HCU stay was 5.9%. In conclusion, all institutions used delirium assessment tools in the ICU/HCU, and most patients received delirium assessment. The prevalence of delirium was 17.9%, and two-thirds of patients had recovered at discharge from ICU/HCU.Trial registration number: UMIN000037834.

Photodynamic therapy for pulmonary mucoepidermoid carcinoma.

Pulmonary mucoepidermoid carcinoma (PMEC) are rare, accounting for 0.1-0.2% of all malignant lung tumors. Furthermore, endobronchial lesions are rare and are more commonly found in the segmental or lobar bronchi. We present, to the best of our knowledge, the first case of successful treatment with photodynamic therapy (PDT) for PMEC. A 77-year-old male presented with cough and hemosputum for 4 months. Chest computed tomography showed a mass in the right intermediate bronchus. Endobronchial biopsy revealed a diagnosis of PMEC. An optimal surgical technique to preserve respiratory function was desirable as most of the tumor emerged from the bronchial glands in the central airways and was of low-grade type. Hence, PDT was performed. Repeat bronchoscopies were performed 5 years after the PDT and showed no evidence of tumor recurrence. PDT is more likely to be effective for low-grade PMECs that are visible on bronchoscopy.

Effects of aging on isoflurane-induced and protein kinase A-mediated activation of ATP-sensitive potassium channels in cultured rat aortic vascular smooth muscle cells.

Isoflurane activates protein kinase A (PKA) in vascular smooth muscle cells (VSMCs), which in turn activates ATP-sensitive potassium (K(ATP)) channels and causes vasodilation. The present study was undertaken to examine whether advanced age influences the effect of isoflurane on K(ATP) channel activity in cultured VSMCs. We used VSMCs obtained from 12- to 15-week-old (adult) and 24- to 25-month-old (aged) male Wistar rats. Electrophysiological experiments were performed using cell-attached and inside-out patch-clamp techniques to monitor the K(ATP) channel activity. Application of isoflurane or forskolin to the bath solution in cell-attached recordings induced a significant increase in K(ATP) channel activity in the VSMCs from the adult group. However, K(ATP) channel opening induced by isoflurane, but not forskolin, was significantly suppressed by aging. On the other hand, cell-free recordings showed similar pharmacologic sensitivity to the K(ATP) channel opener pinacidil, inward rectification, and unitary conductance (40­45 pS) between groups. In addition, direct K(ATP) channel activation by c-PKA in the inside-out patches was similar in both groups. Furthermore, increasing PKA activation in cell-attached patches by CPT-cAMP restored isoflurane's effects in the aged group. These results suggest that aging decreases isoflurane-induced PKA activation, resulting in attenuation of K(ATP) channel opening.

Nitric oxide activates ATP-sensitive potassium channels in mammalian sensory neurons: action by direct S-nitrosylation.

BACKGROUND: ATP-sensitive potassium (KATP) channels in neurons regulate excitability, neurotransmitter release and mediate protection from cell-death. Furthermore, activation of KATP channels is suppressed in DRG neurons after painful-like nerve injury. NO-dependent mechanisms modulate both KATP channels and participate in the pathophysiology and pharmacology of neuropathic pain. Therefore, we investigated NO modulation of KATP channels in control and axotomized DRG neurons. RESULTS: Cell-attached and cell-free recordings of KATP currents in large DRG neurons from control rats (sham surgery, SS) revealed activation of KATP channels by NO exogenously released by the NO donor SNAP, through decreased sensitivity to [ATP]i. This NO-induced KATP channel activation was not altered in ganglia from animals that demonstrated sustained hyperalgesia-type response to nociceptive stimulation following spinal nerve ligation. However, baseline opening of KATP channels and their activation induced by metabolic inhibition was suppressed by axotomy. Failure to block the NO-mediated amplification of KATP currents with specific inhibitors of sGC and PKG indicated that the classical sGC/cGMP/PKG signaling pathway was not involved in the activation by SNAP. NO-induced activation of KATP channels remained intact in cell-free patches, was reversed by DTT, a thiol-reducing agent, and prevented by NEM, a thiol-alkylating agent. Other findings indicated that the mechanisms by which NO activates KATP channels involve direct S-nitrosylation of cysteine residues in the SUR1 subunit. Specifically, current through recombinant wild-type SUR1/Kir6.2 channels expressed in COS7 cells was activated by NO, but channels formed only from truncated isoform Kir6.2 subunits without SUR1 subunits were insensitive to NO. Further, mutagenesis of SUR1 indicated that NO-induced KATP channel activation involves interaction of NO with residues in the NBD1 of the SUR1 subunit. CONCLUSION: NO activates KATP channels in large DRG neurons via direct S-nitrosylation of cysteine residues in the SUR1 subunit. The capacity of NO to activate KATP channels via this mechanism remains intact even after spinal nerve ligation, thus providing opportunities for selective pharmacological enhancement of KATP current even after decrease of this current by painful-like nerve injury.

Distinct roles of left inferior frontal regions that explain individual differences in second language acquisition.

Second language (L2) acquisition is more susceptible to environmental and idiosyncratic factors than first language acquisition. Here, we used functional magnetic resonance imaging for L2 learners of different ages of first exposure (mean: 12.6 and 5.6 years) in a formal school environment, and compared the cortical activations involved in processing English sentences containing either syntactic or spelling errors, where the testing ages and task performances of both groups were matched. We found novel activation patterns in two regions of the left inferior frontal gyrus (IFG) that correlated differentially with the performances of the late and early learners. Specifically, activations of the dorsal and ventral triangular part (F3t) of the left IFG correlated positively with the accuracy of the syntactic task for the late learners, whereas activations of the left ventral F3t correlated negatively with the accuracy for the early learners. In contrast, other cortical regions exhibited differential correlation patterns with the reaction times (RTs) of the syntactic task. Namely, activations of the orbital part (F3O) of the left IFG, as well as those of the left angular gyrus, correlated positively with the RTs for the late learners, whereas those activations correlated negatively with the RTs for the early learners. Moreover, the task-selective activation of the left F3O was maintained for both the late and early learners. These results explain individual differences in L2 acquisition, such that the acquisition of linguistic knowledge in L2 is subserved by at least two distinct inferior frontal regions of the left F3t and F3O.

Bisphosphonate administration prior to tooth extraction delays initial healing of the extraction socket in rats.

Bisphosphonates (BPs) are clinically used for the treatment of bone metabolic abnormalities because they are powerful inhibitors of bone resorption. Osteonecrosis of the jaw has been observed after tooth extraction in a considerable number of BP-treated cancer patients, but the reason for this is not known. We studied the effects of BP on extraction socket healing in rats that were pretreated with BP prior to tooth extraction. Male Wistar rats (approximately 5 weeks old) were divided into experimental (BP) and control groups. In both groups, maxillary right second molars were extracted under general anesthesia. BP group rats were injected with 50 microl (1.0 mg/kg) alendronate into the right buccal alveolar bone every 4 days for 14 days, starting 2 days before tooth extraction. Control group rats were injected with physiological saline instead of alendronate. Rats were euthanized 3, 7, 10 or 14 days after tooth extraction, and maxillary bones were collected. Bone morphometric analysis using microfocus X-ray CT images and calculation of bone-resorption parameters based on hematoxylin and eosin or TRAP-stained pathological sections of the molar region showed that new bone formation in the extraction socket was delayed in the BP group relative to the control group during the first 7 days after extraction. A subsequent increase in new bone formation showed that bone resorption in the BP rats was eventually inhibited. This delay in initial healing may explain the jaw osteonecrosis observed in some BP-treated cancer patients.

Clinicopathological characteristics and treatment strategies for young lung cancer patients.

BACKGROUND: The reported age-specific survival rates of lung cancer patients have been largely inconsistent. Management strategies for younger patients and treatment outcomes are not well characterized. METHODS: Out of the 4,697 lung cancer patients with treatment history at Tokyo Medical University Hospital between January 2000 and December 2014, 266 patients were <49 years of age. Patient characteristics were investigated, and the association of overall survival (OS) with age, sex, stage, and histological type were investigated. RESULTS: The 1-, 3-, and 5-year survival rates in the ≤49 years age group were 82.9%, 64.6%, and 57.0%. Among surgical cases, the survival rate of patients in the ≤49 years age group was significantly better than that in the 50-69 and ≥70 years age groups (P=0.29 and P<0.0001, respectively). In comparison with the OS rate with clinical stages, I, II, and III (but not with clinical stage IV) in the older than 50 years age group, the rates in the ≤49 years age group were better. The 1-, 3-, and 5-year OS rates of females were higher than those of their males. The 1-, 3-, and 5-year OS rates for lung adenocarcinoma patients were higher than that of lung non-adenocarcinoma patients. CONCLUSIONS: Despite the higher proportion of advanced disease, the postoperative survival rate of the younger was higher than that of the older. Aggressive multimodality treatments, including surgery, are more feasible and effective for younger patients as compared with that in older patients.

Thymolipoma combined with hyperthyroidism discovered by neurological symptoms.

Thymolipomas are rare slow-growing mediastinal thymic neoplasms. Most cases are asymptomatic and are sometimes discovered as a huge mass on chest x-ray films. A few cases have been discovered during examinations for other diseases. We report the second case of thymolipoma combined with hyperthyroidism in the English language literature. Neurological symptoms suddenly appeared in a 45-year-old woman. Central nervous system disorder was suggested but no significant abnormalities were found on brain MR nor were there any neurological signs. Several months later, neurological and systemic examinations on admission revealed hyperthyroidism and an anterior mediastinal tumor, 9.0x5.0x3.0 cm in size on chest CT films. Despite treatment of hyperthyroidism by medication, her neurological symptoms remained. Neurologists recommended resection of the mediastinal tumor. Malignancy could not be ruled out because of the irregularity of the tumor appearance on contrast-enhanced chest CT. Furthermore, the tumor appeared to be attached to the ascending aorta, so cytological and/or pathological diagnosis by CT-guided needle biopsy before operation were contraindicated. Extended thymectomy was performed in May 2005. The pathological diagnosis was benign thymolipoma consisting of mature fatty tissue and thymic tissue structures with Hassall's corpuscles. Her neurological symptoms seemed slightly but not markedly improved. The relationship between thymolipoma and hyperthyroidism is still unknown.

Met-RANTES ameliorates fibrous airway obliteration and decreases ERK expression in a murine model of bronchiolitis obliterans.

OBJECTIVES: Bronchiolitis obliterans (BO) is the main cause of late mortality among long-term survivors of lung transplantation. Chemokine-chemokine receptor (CCR) interaction and subsequent recruitment of infiltrating cells to the graft are early events in the development of chronic rejection of transplanted lungs. The present study investigated whether blockade of chemokine receptors CCR1 and CCR5 with Met-regulated-on-activation, normal T cells expressed and secreted (RANTES), an amino-terminal modified derivative of RANTES/CCL5, affects the development of BO in murine model and we sought to determine the expression of RANTES/CCL5 and their relationship with extracellular signal-regulated kinase (ERK). MATERIALS AND METHODS: BALB/c mouse tracheas were heterotopically transplanted into C57Black6 recipients and treated for 21 days with either Met-RANTES at 20 microg/day or vehicle. Animals were killed at 21 days after transplantation for histologic examination of ERK expression. RESULTS: RANTES/CCL5 was highly expressed in allografts compare to isografts. Met-RANTES treatment ameliorated fibrous airway obliteration in a mouse model of BO and decreased ERK expression. CONCLUSION: Blockade of chemokine receptors by Met-RANTES ameliorated airway obliteration and decreased ERK expression. These findings suggest that chemokine receptors CCR1 and CCR5 play significant roles in the development of chronic rejection and ERK may be a new molecular target for chronic rejection.

Differential effects of propofol and isoflurane on glucose utilization and insulin secretion.

AIMS: Volatile anesthetics, such as isoflurane, reverse glucose-induced inhibition of pancreatic adenosine triphosphate-sensitive potassium (K(ATP)) channel activity, resulting in reduced insulin secretion and impaired glucose tolerance. No previous studies have investigated the effects of intravenous anesthetics, such as propofol, on pancreatic K(ATP) channels. We investigated the cellular mechanisms underlying the effects of isoflurane and propofol on pancreatic K(ATP) channels and insulin secretion. MAIN METHODS: Intravenous glucose tolerance tests (IVGTT) were performed on male rabbits. Pancreatic islets were isolated from male rats and used for a perifusion study, measurement of intracellular ATP concentration ([ATP](i)), and patch clamp experiments. KEY FINDINGS: Glucose stimulus significantly increased insulin secretion during propofol anesthesia, but not isoflurane anesthesia, in IVGTT study. In perifusion experiments, both islets exposed to propofol and control islets not exposed to anesthetic had a biphasic insulin secretory response to a high dose of glucose. However, isoflurane markedly inhibited glucose-induced insulin secretion. In a patch clamp study, the relationship between ATP concentration and channel activity could be fitted by the Hill equation with a half-maximal inhibition of 22.4, 15.8, and 218.8 µM in the absence of anesthetic, and with propofol, and isoflurane, respectively. [ATP](i) and single K(ATP) channel conductance did not differ in islets exposed to isoflurane or propofol. SIGNIFICANCE: Our results indicate that isoflurane, but not propofol, decreases the ATP sensitivity of K(ATP) channels and impairs glucose-stimulated insulin release. These differential actions of isoflurane and propofol on ATP sensitivity may explain the differential effects of isoflurane and propofol on insulin release.

Bisphosphonate treatment increases the size of the mandibular condyle and normalizes growth of the mandibular ramus in osteoprotegerin-deficient mice.

Osteoprotegerin (OPG) is a novel secreted member of the tumor necrosis factor receptor family which plays a crucial role in negative regulation of osteoclastic bone resorption. OPG-deficient (OPG-/-) mice develop severe osteoporosis caused by significant enhancement of bone resorption by osteoclasts. We investigated the effect of administering bisphosphonate on mandibular growth and development in OPG-/- mice. Eight-week-old male OPG-/- mice and wild-type (WT) mice were administered bisphosphonate (1.25 mg/kg body weight) intraperitoneally once every 3 days for 30 days. All bone formation-related parameters and bone resorption-related parameters were significantly lower in OPG-/- mice with bisphosphonate than in those without bisphosphonate. The volume of the whole condyle and the mandibular length in OPG-/- mice without bisphosphonate were significantly smaller than in WT mice without bisphosphonate. Bisphosphonate treatment of the OPG-/- mice resulted in an increase in the volume of the mandibular condyle and mandibular ramus length. In fact, the mandibular ramus length in OPG-/- mice with bisphosphonate was similar to the length in WT mice without bisphosphonate. Histologically, the surface irregularity of the mandibular condyle that was observed in the OPG-/- mice without bisphosphonate tended to be less marked in the OPG-/- mice with bisphosphonate, and the proportion of the area of the cartilage layer relative to the whole condyle was significantly larger in OPG-/- mice with bisphosphonate than in those without bisphosphonate. In conclusion, bisphosphonate treatment results in an increase in mandibular condylar dimensions and normalization of mandibular ramus growth.