Modulation of pain perception through transcranial alternating current stimulation and its nonlinear relationship with the simulated electric field magnitude

BACKGROUND

Oscillatory activities observed in multiple regions are closely associated with the experience of pain. Specifically, oscillatory activities within the theta- and beta-frequency bands, observed in the left dorsolateral prefrontal cortex (DLPFC), have been implicated in pain perception among healthy individuals and those with chronic pain. However, their physiological significance remains unclear.

METHODS

We explored the modulation of pain perception in healthy individuals by theta- and beta-band transcranial alternating current stimulation (tACS) over the left DLPFC and examined the relationship between the modulation effect and magnitude of the electric field elicited by tACS in the left DLPFC using computational simulation.

RESULTS

Our findings revealed that both theta- and beta-tACS increased the heat pain threshold during and after stimulation. Notably, the simulated electric field magnitude in the left DLPFC exhibited an inverted U-shaped relationship with the pain modulation effect for theta-tACS.

CONCLUSIONS

Our study findings suggested that there would be an optimal electric field strength to produce a high analgesic effect for theta-tACS.

SIGNIFICANCE

The application of theta- and beta-tACS interventions targeting the left DLPFC might facilitate the treatment of chronic pain. Furthermore, the attainment of effective pain modulation via theta-tACS over the DLPFC warrants the use of optimal stimulus intensity.

Development of a New Method for Simultaneous Quantitation of Plasma Concentrations of Voriconazole and Voriconazole N-Oxide Using Column-Switching LC-MS/MS and Its Application in Therapeutic Drug Monitoring

Background

Voriconazole therapy for fungal infections usually continues for several years and is often administered on an outpatient basis. Maintaining the voriconazole plasma concentration in the therapeutic range is highly important for effective therapy; however, it is difficult to obtain sufficient information to assess the voriconazole concentration in outpatients. Therefore, we developed a method to simultaneously measure the plasma concentrations of voriconazole and its major metabolite, voriconazole N-oxide, to obtain rapid results after outpatient blood collection and before medical consultation and to attain a better understanding of adherence and the drug-drug interactions of voriconazole.

Methods

Fifty microliters of patient plasma was deproteinized with methanol, injected into the liquid chromatography-tandem mass spectrometry system, and purified using an online column. Separation was achieved on an InertSustain C18 column (2.1 mm id × 50 mm, 2 μm) with a mobile phase of 30:70 (0.1% formic acid in water:methanol) at a flow rate of 0.2 mL/min. Detection was performed using electrospray ionization in positive ion multiple reaction monitoring mode.

Results

The analysis time was 4 min. The calibration curve was linear, in the range of 0.1 μg/mL to 20 μg/mL for voriconazole and 0.05 μg/mL to 10 μg/mL for voriconazole N-oxide, with a coefficient of determination at R2 > 0.999.

Conclusion

There is no need to dilute the patient's plasma even if the concentration of voriconazole is near the upper limit of measurement. Furthermore, the short measurement-time could immediately inform physicians of the patient's voriconazole concentration during ambulatory medical care. Simultaneous measurement of voriconazole and voriconazole N-oxide may also be useful for the immediate adjustment of voriconazole dosage in outpatients and would help us to understand adherence or drug-drug interactions in plasma voriconazole concentrations.

Cyclic AMP Signaling Promotes the Differentiation of Human Induced Pluripotent Stem Cells into Intestinal Epithelial Cells

To develop a novel in vitro system for predicting intestinal drug absorption using human induced pluripotent stem (iPS) cell-derived intestinal epithelial cells, the cells need to have sufficient drug-metabolizing enzyme and drug transporter activities. We found that cyclic adenosine monophosphate (cAMP) signaling plays an important role in the differentiation of human iPS cells into intestinal epithelial cells. In this study, we aimed to demonstrate the effects of signaling activation in the intestinal differentiation of human iPS cells and the pharmacokinetic characteristics of human iPS cell-derived intestinal epithelial cells. Human iPS cells were differentiated into intestinal stem cells using activin A and fibroblast growth factor 2. Subsequently, the intestinal stem cells were maturated into intestinal epithelial cells by treatment with 8-bromo-cyclic adenosine monophosphate (8-Br-cAMP) and 3-isobutyl-1-methylxanthine (IBMX), which activate cAMP signaling. The expression levels of intestinal markers and pharmacokinetics-related genes in the differentiated cells were markedly increased by using 8-Br-cAMP and IBMX. In the cells differentiated with the compound we observed cytochrome P450 (CYP) 3A4 inducibility via pregnane X receptor and vitamin D receptor. The metabolic activities of CYP2C9, CYP2C19, CYP2D6, CYP3A4/5, and UDP-glucuronosyltransferase, which are expressed in the human small intestine, were also markedly increased. Furthermore, uptake of glycylsarcosine via peptide transporter 1 was markedly increased. The cells differentiated with the compounds also had drug transporter activities via organic anion transporters and P-glycoprotein. This study is the first to report that the activation of cAMP signaling promotes differentiation of human iPS cell-derived intestinal epithelial cells.

Spiral MRI on a 9.4T Vertical-bore Superconducting Magnet Using Unshielded and Self-shielded Gradient Coils

Spiral MRI sequences were developed for a 9.4T vertical standard bore (54 mm) superconducting magnet using unshielded and self-shielded gradient coils. Clear spiral images with 64-shot scan were obtained with the self-shielded gradient coil, but severe shading artifacts were observed for the spiral-scan images acquired with the unshielded gradient coil. This shading artifact was successfully corrected with a phase-correction technique using reference scans that we developed based on eddy current field measurements. We therefore concluded that spiral imaging sequences can be installed even for unshielded gradient coils if phase corrections are performed using the reference scans.

Echo-Planar Imaging for a 9.4 Tesla Vertical-Bore Superconducting Magnet Using an Unshielded Gradient Coil

Echo-planar imaging (EPI) sequences were developed for a 9.4 Tesla vertical standard bore (~54 mm) superconducting magnet using an unshielded gradient coil optimized for live mice imaging and a data correction technique with reference scans. Because EPI requires fast switching of intense magnetic field gradients, eddy currents were induced in the surrounding metallic materials, e.g., the room temperature bore, and this produced serious artifacts on the EPI images. We solved the problem using an unshielded gradient coil set of proper size (outer diameter = 39 mm, inner diameter = 32 mm) with time control of the current rise and reference scans. The obtained EPI images of a phantom and a plant sample were almost artifact-free and demonstrated the promise of our approach.

Validation of the optimal site in the neck region for detecting swallowing sounds

Recently, the swallowing sound has been used to detect swallowing events non-invasively. A previous study, using an accelerometer, showed that the site over the lateral border of the trachea immediately inferior to the cricoid cartilage was the optimal site for detecting swallowing sounds. However, the optimal site for detection of the swallowing sound using a microphone remains undetermined. To validate the optimal site in the neck region for detecting swallowing sounds. Fourteen healthy subjects (mean age, 27·6 ± 2·2 years; seven male and seven female) participated in this study. Twenty condenser microphones were attached to 20 sites on the left neck surface to detect swallowing sounds. Participants were instructed to swallow five different stimuli three times as follows: Resting saliva, 1 and 5 mL of Japanese tea, and 1 and 5 mL of yoghurt. Mean relative peak intensity was used to indicate the magnitude of the swallowing sound. Sound spectrograms were used to illustrate differences in the properties of swallowing sounds. Mean relative peak intensity number was highest in sites at the inferior border of the mandible just above the sternocleidomastoid muscle (site 11) and sites over the lateral border of the trachea immediately inferior to the cricoid cartilage (site 8). Comparison of spectrograms showed a greater density distribution of higher frequency components at site 11 compared with site 8. These results indicate that the inferior border of the mandible just above the sternocleidomastoid muscle is the optimal site for the detection of swallowing sounds.

Characteristic Analysis of Intestinal Transport in Enterocyte-Like Cells Differentiated from Human Induced Pluripotent Stem Cells

We previously demonstrated that differentiated enterocytes from human induced pluripotent stem (iPS) cells exhibited drug-metabolizing activities and cytochrome P450 CYP3A4 inducibility. The aim of this study was to apply human iPS cell-derived enterocytes in pharmacokinetic studies by investigating the characteristics of drug transport into enterocyte-like cells. Human iPS cells cultured on feeder cells were differentiated into endodermal cells using activin A. These endodermal-like cells were then differentiated into intestinal stem cells by fibroblast growth factor 2. Finally, epidermal growth factor and small-molecule compounds induced the maturation of the intestinal stem cell-like cells. After differentiation, we performed transepithelial electrical resistance (TEER) measurements, immunofluorescence staining, and transport studies. TEER values increased in a time-dependent manner and reached approximately 100 Ω × cm(2) Efflux transport of Hoechst 33342, a substrate of breast cancer resistance protein (BCRP), was observed and inhibited by the BCRP inhibitor Ko143. The uptake of peptide transporter 1 substrate glycylsarcosine was also confirmed and suppressed when the temperature was lowered to 4°C. Using immunofluorescence staining, villin and Na(+)-K(+) ATPase were expressed. These results suggest that human iPS cell-derived enterocytes had loose tight junctions, polarity, as well as uptake and efflux transport functions. In addition, the rank order of apparent membrane permeability coefficient (Papp) values of these test compounds across the enterocyte-like cell membrane corresponded to the fraction absorbance (Fa) values. Therefore, differentiated enterocytes from human iPS cells may provide a useful comprehensive evaluation model of drug transport and metabolism in the small intestine.

Efficacy of Mandibular 2-implant Overdenture: An Updated Meta-analysis on Patient-based Outcomes

The extent of heterogeneity regarding the efficacy of the mandibular 2-implant overdenture is still in question. The aim of this meta-analysis is to provide an update on the existing evidence from randomized controlled trials assessing the efficacy of the mandibular 2-implant overdenture in regard to patient-based outcomes. Electronic searches were carried out to September 2015 through MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, and the Cochrane Systematic Reviews. Only randomized controlled trials that compared conventional dentures with mandibular 2-implant overdentures were included. Patient-based outcomes were assessed, including patient satisfaction and oral health- and general health-related quality of life. Random effects models were used to pool the effect sizes of all included studies. Further stratified analyses and heterogeneity analyses were tested, as was publication bias. In addition to the 7 randomized controlled trials that were included in the previous meta-analysis, 4 new trials were identified and included in this update. A random effects model showed that, when compared with conventional dentures, mandibular 2-implant overdentures significantly improved patient satisfaction (pooled effect size = 0.87, z = 5.31, 95% confidence interval: 0.55 to 1.19, P < 0.0001, χ² = 41.82, df = 8, P < 0.0001, I² = 81%) and oral health-related quality of life (pooled effect size = -0.66, z = 2.72, 95% confidence interval: -1.13 to -0.18, P = 0.007, χ² = 21.26, df = 4, P = 0.0003, I² = 81%). The differences in participant recruitment and their pretreatment condition were important sources of heterogeneity among the studies. Only 1 study investigated the impact of mandibular implant overdentures on perceived general health, and it revealed no between-treatment differences. The 2-implant mandibular overdenture improves patient satisfaction and quality of life for the general edentate population. Health status, poor oral condition, and patient characteristics may effect patient-based outcomes and should be considered by clinicians in treatment planning. Knowledge Transfer Statement: This meta-analysis shows that mandibular 2-implant overdentures are significantly more satisfactory to the general edentate populations than new conventional dentures. The results also show that mandibular 2-implant overdentures provide significantly better oral health-related quality of life than do new conventional dentures. These results should be shared with edentate patients in planning their treatment.

Arthrodesis of the ankle using an anterior sliding tibial graft for osteoarthritis secondary to osteonecrosis of the talus

Aims

This retrospective cohort study compared the results of vascularised and non-vascularised anterior sliding tibial grafts for the treatment of osteoarthritis (OA)of the ankle secondary to osteonecrosis of the talus.

Patients and Methods

We reviewed the clinical and radiological outcomes of 27 patients who underwent arthrodesis with either vascularised or non-vascularised (conventional) grafts, comparing the outcomes (clinical scores, proportion with successful union and time to union) between the two groups. The clinical outcome was assessed using the Mazur and American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot scores. The mean follow-up was 35 months (24 to 68).

Results

The mean outcome scores increased significantly in both groups. In the vascularised graft group, the mean Mazur score improved from 36.9 to 74.6 and the mean AOFAS scale improved from 49.6 to 80.1. In the conventional arthrodesis group, the mean Mazur score improved from 35.5 to 65 and the mean AOFAS scale from 49.2 to 67.6. Complete fusion was achieved in 13 patients (76%) in the vascularised group, but only four (40%) in the conventional group. The clinical outcomes and proportion achieving union were significantly better in the vascularised group compared with the conventional arthrodesis group, although time to union was similar in the two groups. Take home message: Vascularised sliding tibial grafts may be used to achieve arthrodesis in patients with OA of the ankle secondary to osteonecrosis of the talus. Cite this article: Bone Joint J 2016;98-B:359–64.

Motor and cognitive function analysis for home discharge using the Functional Independence Measure in patients undergoing cardiac rehabilitation at a long-term acute-care hospital

BACKGROUND

Although numerous studies on Functional Independence Measure (FIM) analysis in stroke, orthopedic disease, and spinal cord injury patients have been conducted, it has rarely been done in patients undergoing cardiac rehabilitation (CR).

AIM

To verify whether the Functional Independence Measure (FIM) score, and its subscale motor FIM and cognitive FIM, during inpatient CR can be a predictor of a patient's readiness for home discharge by establishing an FIM cutoff value.

DESIGN

A retrospective, observational cohort study

SETTING

This study was conducted at a long-term acute-care hospital.

POPULATION

Participants were in-hospital patients undergoing CR (N.=949).

METHODS

Measurements included motor FIM, cognitive FIM, CR period, FIM gain per week, and discharge disposition. The strongest predictor for home discharge was analyzed by using multiple logistic regression analysis, and the cutoff value of the FIM score for home discharge was determined by using receiver operating characteristic (ROC) curves.

RESULTS

Discharge to home was possible in 723 patients (76.2%), whereas 226 patients (23.8%) had other outcomes. In univariate analysis, a motor FIM gain per week of five points was achieved in the home discharge group. Multiple logistic regression analysis revealed that Body Mass Index, number of comorbidities, motor FIM at discharge, cognitive FIM gain, and CR period were predictive factors with 89.6% predictive ability. ROC curve analysis showed that the cutoff value was a discharge motor FIM score of 63/64 points with 0.912 areas under the curve.

CONCLUSION

Discharge motor FIM and cognitive FIM gain were predictive factors for home discharge. A motor FIM gain per week of five points and discharge motor FIM score of 64 points at the end of inpatient CR may be important predictors of a patient's readiness for discharge to home.

CLINICAL REHABILITATION IMPACT

The findings of this study indicate an alternative goal to the activities of daily living in inpatients with cardiovascular disease.

A new form of surgical treatment for patients with avascular necrosis of the talus and secondary osteoarthritis of the ankle

A new method of vascularised tibial grafting has been developed for the treatment of avascular necrosis (AVN) of the talus and secondary osteoarthritis (OA) of the ankle. We used 40 cadavers to identify the vascular anatomy of the distal tibia in order to establish how to elevate a vascularised tibial graft safely. Between 2008 and 2012, eight patients (three male, five female, mean age 50 years; 26 to 68) with isolated AVN of the talus and 12 patients (four male, eight female, mean age 58 years; 23 to 76) with secondary OA underwent vascularised bone grafting from the distal tibia either to revascularise the talus or for arthrodesis. The radiological and clinical outcomes were evaluated at a mean follow-up of 31 months (24 to 62). The peri-malleolar arterial arch was confirmed in the cadaveric study. A vascularised bone graft could be elevated safely using the peri-malleolar pedicle. The clinical outcomes for the group with AVN of the talus assessed with the mean Mazur ankle grading scores, improved significantly from 39 points (21 to 48) pre-operatively to 81 points (73 to 90) at the final follow-up (p = 0.01). In all eight revascularisations, bone healing was obtained without progression to talar collapse, and union was established in 11 of 12 vascularised arthrodeses at a mean follow-up of 34 months (24 to 58). MRI showed revascularisation of the talus in all patients. We conclude that a vascularised tibial graft can be used both for revascularisation of the talus and for the arthrodesis of the ankle in patients with OA secondary to AVN of the talus.

Generation of enterocyte-like cells with pharmacokinetic functions from human induced pluripotent stem cells using small-molecule compounds

The small intestine plays an important role in all aspects of pharmacokinetics, but there is no system for the comprehensive evaluation of small-intestinal pharmacokinetics, including drug metabolism and absorption. In this study, we aimed to construct an intestinal pharmacokinetics evaluation system and to generate pharmacokinetically functional enterocytes from human induced pluripotent stem cells. Using activin A and fibroblast growth factor 2, we differentiated these stem cells into intestinal stem cell-like cells, and the resulting cells were differentiated into enterocytes in a medium containing epidermal growth factor and small-molecule compounds. The differentiated cells expressed intestinal marker genes and drug transporters. The expression of sucrase-isomaltase, an intestine-specific marker, was markedly increased by small-molecule compounds. The cells exhibited activities of drug-metabolizing enzymes expressed in enterocytes, including CYP1A1/2, CYP2C9, CYP2C19, CYP2D6, CYP3A4/5, UGT, and sulfotransferase. Fluorescence-labeled dipeptide uptake into the cells was observed and was inhibited by ibuprofen, an inhibitor of the intestinal oligopeptide transporter solute carrier 15A1/PEPT1. CYP3A4 mRNA expression level was increased by these compounds and induced by the addition of 1α,25-dihydroxyvitamin D3. CYP3A4/5 activity was also induced by 1α,25-dihydroxyvitamin D3 in cells differentiated in the presence of the compounds. All these results show that we have generated enterocyte-like cells that have pharmacokinetic functions, and we have identified small-molecule compounds that are effective for promoting intestinal differentiation and the gain of pharmacokinetic functions. Our enterocyte-like cells would be useful material for developing a novel evaluation system to predict human intestinal pharmacokinetics.

A novel automated detection system for swallowing sounds during eating and speech under everyday conditions

The wave analysis of swallowing sounds has been receiving attention because the recording process is easy and non-invasive. However, up until now, an expert has been needed to visually examine the entire recorded wave to distinguish swallowing from other sounds. The purpose of this study was to establish a methodology to automatically distinguish the sound of swallowing from sound data recorded during a meal in the presence of everyday ambient sound. Seven healthy participants (mean age: 26·7 ± 1·3 years) participated in this study. A laryngeal microphone and a condenser microphone attached to the nostril were used for simultaneous recording. Recoding took place while participants were taking a meal and talking with a conversational partner. Participants were instructed to step on a foot pedal trigger switch when they swallowed, representing self-enumeration of swallowing, and also to achieve six additional noise-making tasks during the meal in a randomised manner. The automated analysis system correctly detected 342 out of the 352 self-enumerated swallowing events (sensitivity: 97·2%) and 479 out of the 503 semblable wave periods of swallowing (specificity: 95·2%). In this study, the automated detection system for swallowing sounds using a nostril microphone was able to detect the swallowing event with high sensitivity and specificity even under the conditions of daily life, thus showing potential utility in the diagnosis or screening of dysphagic patients in future studies.

Effect of nasal speaking valve on speech intelligibility under velopharyngeal incompetence: a questionnaire survey

Velopharyngeal incompetence is known as a contributing factor to speech disorders. Suwaki et al. reported that nasal speaking valve (NSV) could improve dysarthria by regulating nasal emission utilising one-way valve. However, disease or condition which would be susceptible to treatment by NSV has not been clarified yet. This study aimed to evaluate the effect of NSV by questionnaire survey using ready-made NSV. Subjects were recruited through the internet bulletin, and NSV survey set was sent to the applicant. Sixty-six participants, who agreed to participate in this study, used NSV and mailed back the questionnaire which included self-evaluation and third-party evaluation of speech intelligibility. Statistical analysis revealed that the use of NSV resulted in significant speech intelligibility improvement in both self-evaluation and third-party evaluation (P < 0·01). Regarding the type of underlying disease of dysarthria, significant effect of NSV on self-evaluation of speech intelligibility could be observed in cerebrovascular disease and neurodegenerative disease (P < 0·01) and that on third-party evaluation in neurodegenerative disease (P < 0·01). Eighty-six percent of subjects showed improvement of speech intelligibility by shutting up nostrils by fingers, and the significant effect of NSV on both self-evaluation and third-party evaluation of speech intelligibility was observed (P < 0·001). From the results of this study, it was suggested that NSV would be effective in cerebrovascular disease and neurodegenerative disease, as well as in subjects whose speech intelligibility was improved by closing nostrils.

Safety and feasibility of physical therapy in cytopenic patients during allogeneic haematopoietic stem cell transplantation

This study aimed to investigate the safety and feasibility of physical therapy in cytopenic patients undergoing allogeneic haematopoietic stem cell transplantation (allo-HSCT), and to investigate the effect of physical therapy on physiological functions and quality of life (QOL) in allo-HSCT patients. The study cohort included 321 patients who underwent allo-HSCT. To investigate the safety and feasibility of physical therapy during cytopenia, patients were assigned to the physical therapy group (n = 227) or the control group (n = 94). To determine the effects of physical therapy, patients were divided according to the frequency with which they underwent physical therapy (n = 51 per group). Handgrip strength, knee extensor strength and a 6-min walk test were used as measures of physiological function. Short-Form 36 was used to assess QOL. The physical therapy group had higher rate of achieving engraftment and lower death rate than the control group (P < 0.05). After HSCT, the high-frequency physical therapy group showed significantly less decline than the low-frequency physical therapy group with respect to physical functioning of QOL (P < 0.01). Physical therapy is quite beneficial and can be performed safely and feasibly in cytopenic patients during allo-HSCT.

Short-term dynamics of the carbon isotope composition of CO2 emitted from a wheat agroecosystem--physiological and environmental controls

Understanding environmental and physiological controls of the variations in δ(13) C of CO(2) respired (δ(13) C(R)) from different compartments of an ecosystem is important for separation of CO(2) fluxes and to assess coupling between assimilation and respiration. In a wheat field, over 3 days we characterised the temporal dynamics of δ(13) C(R) from shoots and roots, from the soil and from the whole agroecosystem. To evaluate the basis of potential variations in δ(13) C(R), we also measured δ(13) C in different organic matter pools, as well as meteorological and gas exchange parameters. We observed strong diel variations up to ca. 6% in shoot, root and soil δ(13) C(R), but not in δ(13) C of the putative organic substrates for respiration, which varied by not more than ca. 1% within 24 h. Whole ecosystem-respired CO(2) was least depleted in (13) C in the afternoon and most negative in the early morning. We assume that temporally variable respiratory carbon isotope fractionation and changes in fluxes through metabolic pathways, rather than photosynthetic carbon isotope fractionation, governs the δ(13) C of respired CO(2) at the diel scale, and thus provides insights into the metabolic processes related to respiration under field conditions.

Congenital unilateral upper limb muscular hypertrophy associated with contracture of an extrinsic extensor tendon

We report a case of congenital unilateral upper limb muscular hypertrophy which presented with loss of extensor tendon excursion of a single digit in late adolescence. The reason for the problem arising is not clear and is not clearly explained by the underlying congenital pathology.

Dynamic 3D-CT angiography

BACKGROUND AND PURPOSE

3D-CT angiography (3D-CTA), a vessel-cast technique, is useful in the diagnosis of patients with brain lesions and cerebrovascular disease. However, it provides no information on blood-flow dynamics. Therefore, we developed a new technique, dynamic 3D-CTA (d3D-CTA), that yields 3D images of the vasculature and allows assessment of the hemodynamics and of the cerebral perfusion.

METHODS

We subjected 12 patients to d3D-CTA; 7 had brain tumors, 4 had arteriovenous malformations (AVMs), and 1 presented with cervical internal carotid artery occlusion. d3D-CTA was performed with a multidetector-row CT scanner with 64 detectors; the parameters were 0.5-mm section thickness, 0.5 seconds per rotation, 135 kV, and 150 mA. Contrast medium (total volume, 30-35 mL) was injected at 6-7 mL/s; scanning was started after a 5-second delay. Scans were generated with volume-rendering reconstruction and displayed in cine mode.

RESULTS

We succeeded in obtaining d3D-CTA scans in all cases. The scans yielded 3D information on the vascular structures and hemodynamics and on the status of the cerebral perfusion.

CONCLUSION

d3D-CTA facilitates the acquisition of information on the vascular and cerebral dynamic blood flow on 3D-CTA images. Despite the relatively high radiation exposure and contrast injection speed and its limited scan range, this technique is useful for the diagnosis of patients with brain tumors or cerebrovascular disease and for treatment planning.

Vacuum ultraviolet spectroscopy of Ce(3+)-doped SrMgF(4) with superlattice structure

X-ray diffraction of Ce(3+)-doped SrMgF(4) (SMF:Ce) crystals shows a superlattice structure, reflecting the distribution of Ce(3+) polyhedra centres observed in optical experiments. Optical absorption bands and fluorescence bands from the Ce(3+) polyhedra centres overlap in the vacuum ultraviolet (VUV) and ultraviolet (UV) regions, respectively, so that wide pumping and tuning ranges are expected for laser operation. The SMF:Ce crystals, as well as the isomorphous BaMgF(4), are candidates for a tunable laser gain material with nonlinear properties. The optical absorption, excitation, and fluorescence bands observed in the SMF:Ce crystals at low temperatures are ascribed to five distinct fluorescent centres. Three centres have well-known Ce(3+) optical characters, for example, fluorescence with double peaks separated by 2000 cm(-1) and five resolved absorption/excitation bands. These centres are assigned to Ce(3+)-polyhedra classified by weak and strong crystal fields as a consequence of the superlattice structure. The other two fluorescence bands observed in the visible region have 1.5-2 times larger linewidths than those of the former three bands. These bands are interpreted as optical transitions from complexes consisting of Ce(3+) and one or two electrons trapped at a vacancy of the nearest neighbour F(-) ligand ions.

A new neuromodulatory pathway with a glial contribution mediated via A(2a) adenosine receptors

A low concentration (10 nM) of adenosine potentiated hippocampal neuronal activity via A(2a) adenosine receptors without affecting presynaptic glutamate release or postsynaptic glutamatergic conductance. Adenosine inhibited glutamate uptake through the glial glutamate transporter, GLT-1, via A(2a) adenosine receptors. In addition, adenosine stimulated GLT-1-independent glutamate release from astrocytes, possibly in response to a rise in intracellular Ca(2+), via A(2a) adenosine receptors involving PKA activation. Those adenosine actions could lead to an increase in synaptic glutamate concentrations responsible for the potentiation of hippocampal neuronal activity. The results of the present study thus represent a novel neuromodulatory pathway with a glial contribution, bearing both inhibition of GLT-1 function and stimulation of glial glutamate release, as mediated via A(2a) adenosine receptors.

Role of glial glutamate transporters in the facilitatory action of FK960 on hippocampal neurotransmission

We found previously that N-(4-acetyl-1-piperazinyl)-p-fluorobenzamide monohydrate (FK960) facilitated hippocampal neurotransmission in the dentate gyrus of rat hippocampal slices. The present study was conducted to understand the mechanism underlying the facilitatory action of FK960. The facilitation was inhibited by H-89, an inhibitor of cAMP-dependent protein kinase (PKA), but it was not affected by cycloheximide, a protein synthesis blocker. In cultured rat hippocampal neurons, the drug had no effect on either spontaneous miniature excitatory postsynaptic currents or whole-cell membrane currents evoked by glutamate, kainate, or NMDA, suggesting that the facilitatory action of FK960 is not caused by increasing presynaptic transmitter release or excitatory postsynaptic conductances. FK960 inhibited responses of the glial glutamate transporter, GLT-1, expressed in Xenopus oocytes, and a similar effect was found with cultured rat astrocytes. The FK960 action was inhibited in the presence of H-89. The results of the present study thus suggest that FK960 facilitates hippocampal neurotransmission by inhibiting GLT-1 glial glutamate reuptake via a PKA pathway, thereby increasing synaptic glutamate concentrations.

Catalase catalyzes nitrotyrosine formation from sodium azide and hydrogen peroxide

Sodium azide (NaN3) is known as an inhibitor of catalase, and a nitric oxide (NO) donor in the presence of catalase and H2O2. We showed here that catalase-catalyzed oxidation of NaN3 can generate reactive nitrogen species which contribute to tyrosine nitration in the presence of H2O2. The formation of free-tyrosine nitration and protein-bound tyrosine nitration by the NaN3/catalase/H2O2 system showed a maximum level at pH 6.0. Free-tyrosine nitration induced by peroxynitrite was inhibited by ethanol and dimethylsulfoxide (DMSO), and augmented by superoxide dismutase (SOD). However, free-tyrosine nitration induced by the NaN3/catalase/H2O2 system was not affected by ethanol, DMSO and SOD. NO2- and NO donating agents did not affect free-tyrosine nitration by the NaN3/catalase/H2O2 system. The reaction of NaN3 with hydroxyl radical generating system showed free-tyrosine nitration, but no formation of nitrite and nitrate. The generation of nitrite (NO2-) and nitrate (NO3-) by the NaN3/catalase/H2O2 system was maximal at pH 5.0. These results suggested that the oxidation of NaN3 by the catalase/H2O2 system generates unknown peroxynitrite-like reactive nitrogen intermediates, which contribute to tyrosine nitration.

Antidromic effect of calcitonin gene-related peptide containing nerves on cerebral arteries in rats--a possible role of sensory nerves on cerebral circulatio

It has generally been thought that the neurogenic control of cerebral circulation is decided mainly by the autonomic nervous system. Recent studies, however, indicate that sensory nerves rich in calcitonin gene-related peptide (CGRP) are also distributed on cerebral arteries. CGRP is one of neuropeptides that has strong vasodilative effect. This indicates that sensory nerves may antidromically dilate cerebral arteries mediated by CGRP. The aim of this study is to investigate the relationship between the CGRP containing nerves and cerebral circulation. Firstly, we developed a selective denervation model of CGRP containing nerves. The denervation was performed with intrathecal administration of capsaicin in rats. Secondly, we measured the change of regional cerebral blood flow (rCBF) during the occlusion of bilateral common carotid artery or systemic hypotension. CGRP immunoreactivity around cerebral arteries disappeared after capsaicin treatment. The rCBF during the occlusion of bilateral common carotid artery decreased more in the capsaicin group than in the control group. There was no significant difference in the changes of rCBF during systemic hypotension. These results showed that CGRP containing nerves would participate in the vascular response of cerebral arteries. It is likely that sensory nerves with CGRP should have antidromic effect on cerebral circulation.

Addition of Maitake D-fraction reduces the effective dosage of vancomycin for the treatment of Listeria-infected mice

Maitake D-fraction, beta1,6-glucan having beta1,3-branches, has been reported to activate the immune system of the host. To elucidate whether the D-fraction can reduce the clinical effective dosage of antibiotics in the treatment of opportunistic bacterial infection, we examined the effects of D-fraction on the treatment of Listeria monocytogenes-infected mice in combination with vancomycine (VCM), the only antibiotic used for methicillin-resistant Staphylococcus aureus (MRSA). Listeria-infection was introduced by its inoculation into the abdominal cavity of mice. Without treatment, all inoculated mice died within 3 days after the inoculation. In contrast, in the mice treated with combined therapy of D-faction (10 mg/kg per day) and VCM (10 mg/kg per day), the survival rate was maintained at 60% on the 10th day after the inoculation, which was superior to that of mice treated with VCM alone (10 mg/kg per day). To investigate the mechanism underlying the reinforcement of VCM treatment by the D-fraction, the activities of macrophages and splenic T cells of Listeria-infected mice were evaluated. In mice administered with both D-fraction and VCM, macrophages produced 2.7 times as much interleukin-1 as that of non-treated control mice. The bactericidal activity of splenic T cells was also enhanced by 2.6 times of that of non-treated control mice. These results indicate that D-fraction activates immuno-competent cells, induced cytokine production, and consequently enhanced the bactericidal activities of the splenic T cells against Listeria monocytogenes, suggesting the clinical benefit of D-fraction in the case of anti-bacterial treatment for patients with high risks.

Effects of maitake (Grifola frondosa) D-Fraction on the carcinoma angiogenesis

We have reported that D-Fraction extracted from maitake (Grifola frondosa), activates immune competent cells, and indicates anti-tumor activities. The D-Fraction was observed to induce angiogenesis in vivo and to enhance the proliferation capability and migration capability of human vascular endothelial cell in vitro. The D-Fraction also increased plasma vascular endothelial growth factor (VEGF) concentration significantly. Also VEGF and TNF-alpha production by the activated peritoneal macrophages were enhanced. These results suggest that the anti-tumor activity of the D-Fraction is not only associated with the activation of the immuno-competent cells but also possibly related to the carcinoma angiogenesis induction.

Technique for fixing a temporalis muscle using a titanium plate to the implanted hydroxyapatite ceramics for bone defects

We devised a technique to fix the temporalis muscle to the transplanted hydroxyapatite implant by using a titanium plate, which is fixed to the hydroxyapatite ceramic implant by screws and achieves good clinical results. The size, shape, and curvature of the hydroxyapatite ceramic implants were determined according to full-scale models fabricated using the laser lithographic modeling method from computed tomography data. A titanium plate was then fixed with screws on the implant before implantation, and then the temporalis muscle was refixed to the holes at both ends of the plate. The application of this technique reduced the hospitalization time and achieved good results esthetically.

Monoclinic superstructure of SrMgF4 with perovskite-type slabs

Crystals of Ce-doped SrMgF4, strontium magnesium tetrafluoride, have been found to have a monoclinic P2(1) structure with doubled a and tripled c cell lengths compared with the orthorhombic Cmcm structure previously reported in the literature. The perovskite-type slabs, composed of corner-sharing MgF6 octahedra and Sr atoms, are stacked along the b axis. The six crystallographically independent MgF6 octahedra are rotated so as to provide long periodicities along a and c. The coordination numbers and bond distances around the six crystallographically independent Sr atoms are slightly different in each case. In the superstructure, the Sr atoms lie on local mirror planes which are thought to originate at the high-temperature phase transition.

Spinal evoked potentials following transcranial magnetic stimulation

Motor evoked potentials by magnetic stimulation is less invasive and causes no pain as opposed to high current electric stimulation. However, the distribution of the magnetic field generated by the round coil has not been fully studied. In this report, we mapped the extent of the magnetic induction flux density, and then the evoked potentials from the spinal cord were investigated by transcranial magnetic stimulation. We also examined the origin of the evoked potentials obtained by the magnetic stimulation. The following results were obtained. The magnetic induction flux density was at its maximum at the edge of the coil. The potentials consisted of a first negative wave and subsequent multiphasic waves. The first negative wave was similar to a response of the subcorticospinal tract in the lower brain stem, while the subsequent multiphasic waves were similar to those of the pyramidal tract. Although magnetic stimulation has certain advantages over electric stimulation, several problems remain to be solved for the monitoring of motor functions in the clinical settings.

Three-dimensional computerized tomography angiography—guided surgery of acutely ruptured cerebral anuerysms

Object. The aim of this study was to assess whether aneurysm surgery can be performed in patients with ruptured cerebral aneurysms by using three-dimensional computerized tomography (3D-CT) angiography alone, without conventional catheter angiography.

Methods. In a previous study, 60 patients with subarachnoid hemorrhage (SAH) from ruptured aneurysms were prospectively evaluated using both 3D-CT and conventional angiography, which resulted in a 100% accuracy for 3D-CT angiography in the diagnosis of ruptured aneurysms, and a 96% accuracy in the identification of associated unruptured aneurysms. The results led the authors to consider replacing conventional angiography with 3D-CT angiography for use in diagnosing ruptured aneurysms, and to perform surgery aided by 3D-CT angiography alone without conventional angiography. Based on the results, 100 consecutive patients with SAH who had undergone surgery in the acute stage based on 3D-CT angiography findings have been studied since December 1996. One hundred ruptured aneurysms, including 41 associated unruptured lesions, were detected using 3D-CT angiography. In seven of 100 ruptured aneurysms, which included four dissecting vertebral artery aneurysms, two basilar artery (BA) tip aneurysms, and one BA—superior cerebellar artery aneurysm, 3D-CT angiography was followed by conventional angiography to acquire diagnostic confirmation or information about the vein of Labbé, which was needed to guide the surgical approach for BA tip aneurysms. All of the ruptured aneurysms were confirmed at surgery and treated successfully. Ninety-three patients who underwent operation with the aid of 3D-CT angiography only had no complications related to the lack of information gathered by conventional angiography. The 3D-CT angiography studies provided the authors with the aneurysm location as well as surgically important information on the configuration of its sac and neck, the presence of calcification in the aneurysm wall, and its relationship to the adjacent vessels and bone structures.

Conclusions The authors believe that 3D-CT angiography can replace conventional angiography in the diagnosis of ruptured aneurysms and that surgery can be performed in almost all acutely ruptured aneurysms by using only 3D-CT angiography without conventional angiography.

Cloning of a cDNA for a constitutive NRT1 transporter from soybean and comparison of gene expression of soybean NRT1 transporters

We have isolated a cDNA for a putative transporter, named GmNRT1-3, in the NRT1 family from soybean. It was predicted to have a similar topological structure not only to both GmNRT1-1 and GmNRT1-2 reported previously, but also to other members of the family. Two other cDNAs isolated have parts of the sequence for putative NRT1 transporters, GmNRT1-4 and GmNRT1-5, suggesting that at least five NRT1 transporters occur in soybean. These GmNRT1 genes and the GmNRT2 gene, encoding a soybean NRT2 nitrate transporter, showed different expression patterns to each other under various nitrogen conditions. Specifically, GmNRT1-3 was constitutively expressed in both roots and leaves, while GmNRT1-2 was gradually expressed as the roots developed in the presence of ammonium as a nitrogen source, but not in the presence of both ammonium and nitrate. Based on these results, we discussed the possible regulation in the expression and role of these transporters in nitrate uptake.

Opsonic function and concentration of human serum ficolin/P35

Collectins, C-type (Ca2+-dependent) animal lectins with both collagenous and carbohydrate recognition domains, function as opsonins against pathogens. We previously described an N-acetylglucosamine (GlcNAc)-binding lectin (ficolin/P35) with a collagen- and a fibrinogen-like sequence present in human serum. In this report we show that ficolin/P35 can serve as an opsonin and enhance the clearance of pathogens having surface GlcNAc. Ficolin/P35 bound to an Ra chemotype strain of Salmonella typhimurium (TV119) which has an exposed GlcNAc at the non-reducing termini of the polysaccharide. On the other hand, ficolin/P35 did not bind to LT2, a smooth type strain of S. typhimurium with additional O-polysaccharides covering GlcNAc. Ficolin/P35 enhanced the uptake of TV119 by monocytes or polymorphonuclear leukocytes but had no opsonic activity towards LT2. These results suggest that, like collectins, ficolin/P35 is a collagenous lectin which has a role in innate immunity against certain pathogenic organisms by acting as an opsonin. We prepared monoclonal antibodies against ficolin/P35 and developed an enzyme-linked immunosorbent assay (ELISA) for measuring ficolin/P35 concentrations in humans. The mean serum concentration of ficolin/P35 from 130 normal individuals was estimated to be 13.7 microg/ml.

Effects of maitake (Grifola frondosa) polysaccharide on collagen-induced arthritis in mice

We recently reported the anti-hepatitis effect of a polysaccharide, designated as the D-fraction, extracted from maitake. Its effect includes immuno-regulating activities. We investigated the effect of the glucan in collagen-induced arthritis (CIA). The D-fraction was administered to CIA mice for 30 consecutive days. Arthritis development was observed from the 4th day after the second immunization. The D-fraction did not have any influence on anti-type II collagen antibodies in blood serum or activated B cells. To determine how cellular immunity may be involved in the development of CIA, ratios of CD4+ T cells and their activated form in the axillary and inguinal lymph node T cells were detected by flow cytometry analysis. The ratios were not different between the D-fraction group and the control group. However, interleukin-1beta, granulocyte-macrophage colony-stimulating factor and tumor necrosis factor-alpha productions from splenic macrophages were significantly increased to 2.0, 4.7 and 1.9 times the control group level, respectively. The ratio of macrophages in the whole spleen cells was 2.3 times that of the control group, and their migrating ability was 1.9 times higher. Based on these results, we concluded that the arthritis development induced by D-fraction administration is attributable to the activation of splenic macrophages.

Experimental study of medullary trigeminal evoked potentials: development of a new method of intraoperative monitoring of the medulla oblongata

OBJECT

The goal of this study was to develop a new method of intraoperative monitoring of functions located in the lateral portion of the medulla oblongata. Based on the fact that the spinal trigeminal nucleus and tract are located in the lateral portion of the medulla oblongata, the authors intended to investigate the efficacy of trigeminal evoked potentials (TEPs) in intraoperative monitoring for assessing functions of the medulla oblongata.

METHODS

Trigeminal evoked potentials induced by electrical stimulation of the infraorbital nerve were recorded from the dorsolateral portion of the medulla oblongata (M-TEP) and the cerebral sensory cortex (C-TEP) in dogs. When the lateral one-sixth portion of the medulla was cut, the amplitude of the M-TEP decreased markedly, but the amplitude of the C-TEP and the somatosensory evoked potential (SSEP) did not decrease. When the lateral one-third portion of the medulla was cut, the amplitude of the SSEP decreased, but that of the C-TEP showed no change. When the medulla was retracted, the amplitude of the M-TEP was more sensitive than that of SSEP. Pathological examinations revealed that retraction force less than 10 g and a reduction in the amplitude of the M-TEP less than 50% were safe.

CONCLUSIONS

These results suggest that M-TEPs obtained from the dorsolateral portion of the medulla oblongata by electrical stimulation of the trigeminal nerve are clinically applicable as a new means of intraoperative monitoring of the functions of the medulla oblongata.

Involvement of the actin cytoskeleton in the regulation of serotonin transporter (SET) activity: possible mechanism underlying SET regulation by protein kinase C

Our previous report has revealed that PKC activation by 12-O-tetradecanoylphorbol 13-acetate (TPA) inhibited the uptake activity of serotonin transporter (SET), via an indirect mechanism unknown, but not likely via direct phosphorylation of SET by PKC (Sakai et al., 1997. J. Neurochem. 68, 2618-2624). To elucidate whether PKC can directly phosphorylate SET in vivo, FLAG-tagged SET (FLAG-SET) was expressed in COS-7 cells and the TPA-induced incorporation of (32)P into immunoprecipitated FLAG-SET was examined. PKC activation with TPA caused no phosphorylation of FLAG-SET expressed in COS-7 cells. On the other hand, morphological change associated with the disruption of filamentous actin (F-actin) was seen in TPA-treated COS-7 cells. Therefore, we studied the effects of cytochalasin D, an inhibitor of actin polymerization, on the uptake activity of the serotonin transporter (SET) to elucidate whether the actin cytoskeleton modulates the SET uptake activity. The treatment with cytochalasin D inhibited the uptake activity of both native and recombinant SET in a concentration-dependent manner. Eadie-Hofstee analysis revealed that cytochalasin D down-regulated the recombinant SET uptake activity by reducing the V(max), but not the K(m), mimicking the result observed in TPA-induced inhibition of SET activity (Sakai et al., 1997. J. Neurochem. 68, 2618-2624). The cytochalasin D-induced inhibition of SET activity was partially, but significantly, reversed by jasplakinolide, a cell permeable stabilizer of F-actin, whereas TPA-induced inhibition of SET activity was not reversed by jasplakinolide. To elucidate whether the subcellular localization of SET was changed in response to cytochalasin D or TPA, we expressed the SET fused with the green fluorescent protein (SET-GFP) in COS-7 cells and observed the subcellular distribution of SET-GFP under a confocal laser scanning fluorescent microscope. Neither cytochalasin D nor TPA markedly changed the SET-GFP cellular localization, although these drugs caused morphological change in the GFP-transfected COS-7 cells. In addition, SET activity was not altered by the treatment with either colchicine, an inhibitor of microtubule polymerization, or taxol, a stabilizer of microtubule polymerization. These results suggest that the SET uptake activity was regulated by the state of the actin cytoskeleton and that TPA exerts its inhibitory action on SET activity, in part, via disruption of F-actin and subsequent morphological change in cells.