Action of GABAB receptor on local network oscillation in somatosensory cortex of oral part: focusing on NMDA receptor

The balance of activity between glutamatergic and GABAergic networks is particularly important for oscillatory neural activities in the brain. Here, we investigated the roles of GABAB receptors in network oscillation in the oral somatosensory cortex (OSC), focusing on NMDA receptors. Neural oscillation at the frequency of 8-10 Hz was elicited in rat brain slices after caffeine application. Oscillations comprised a non-NMDA receptor-dependent initial phase and a later NMDA receptor-dependent oscillatory phase, with the oscillator located in the upper layer of the OSC. Baclofen was applied to investigate the actions of GABAB receptors. The later NMDA receptor-dependent oscillatory phase completely disappeared, but the initial phase did not. These results suggest that GABAB receptors mainly act on NMDA receptor, in which metabotropic actions of GABAB receptors may contribute to the attenuation of NMDA receptor activities. A regulatory system for network oscillation involving GABAB receptors may be present in the OSC.

Functional Dissection of Ipsilateral and Contralateral Neural Activity Propagation Using Voltage-Sensitive Dye Imaging in Mouse Prefrontal Cortex

Prefrontal cortex (PFC) intrahemispheric activity and the interhemispheric connection have a significant impact on neuropsychiatric disorder pathology. This study aimed to generate a functional map of FC intrahemispheric and interhemispheric connections. Functional dissection of mouse PFCs was performed using the voltage-sensitive dye (VSD) imaging method with high speed (1 ms/frame), high resolution (256 × 256 pixels), and a large field of view (∼10 mm). Acute serial 350 μm slices were prepared from the bregma covering the PFC and numbered 1-5 based on their distance from the bregma (i.e., 1.70, 1.34, 0.98, 0.62, and 0.26 mm) with reference to the Mouse Brain Atlas (Paxinos and Franklin, 2008). The neural response to electrical stimulation was measured at nine sites and then averaged, and a functional map of the propagation patterns was created. Intracortical propagation was observed in slices 3-5, encompassing the anterior cingulate cortex (ACC) and corpus callosum (CC). The activity reached area 33 of the ACC. Direct white matter stimulation activated area 33 in both hemispheres. Similar findings were obtained via DiI staining of the CC. Imaging analysis revealed directional biases in neural signals traveling within the ACC, whereby the signal transmission speed and probability varied based on the signal direction. Specifically, the spread of neural signals from cg2 to cg1 was stronger than that from cingulate cortex area 1(cg1) to cingulate cortex area 2(cg2), which has implications for interhemispheric functional connections. These findings highlight the importance of understanding the PFC functional anatomy in evaluating neuromodulators like serotonin and dopamine, as well as other factors related to neuropsychiatric diseases.

Assessing seizure liability in vitro with voltage-sensitive dye imaging in mouse hippocampal slices

Non-clinical toxicology is a major cause of drug candidate attrition during development. In particular, drug-induced seizures are the most common finding in central nervous system (CNS) toxicity. Current safety pharmacology tests for assessing CNS functions are often inadequate in detecting seizure-inducing compounds early in drug development, leading to significant delays. This paper presents an in vitro seizure liability assay using voltage-sensitive dye (VSD) imaging techniques in hippocampal brain slices, offering a powerful alternative to traditional electrophysiological methods. Hippocampal slices were isolated from mice, and VSD optical responses evoked by stimulating the Schaffer collateral pathway were recorded and analyzed in the stratum radiatum (SR) and stratum pyramidale (SP). VSDs allow for the comprehensive visualization of neuronal action potentials and postsynaptic potentials on a millisecond timescale. By employing this approach, we investigated the in vitro drug-induced seizure liability of representative pro-convulsant compounds. Picrotoxin (PiTX; 1-100 μM), gabazine (GZ; 0.1-10 μM), and 4-aminopyridine (4AP; 10-100 μM) exhibited seizure-like responses in the hippocampus, but pilocarpine hydrochloride (Pilo; 10-100 μM) did not. Our findings demonstrate the potential of VSD-based assays in identifying seizurogenic compounds during early drug discovery, thereby reducing delays in drug development and providing insights into the mechanisms underlying seizure induction and the associated risks of pro-convulsant compounds.

Transcriptome dynamics of rice in natura: Response of above and below ground organs to microclimate

The long-term dynamics of the transcriptome under natural field conditions remain unclear. We conducted comprehensive gene expression analyses of rice leaves and roots grown under natural field conditions for a long period, from the tillering stage to the ripening stage. In this experiment, changes in the transcriptome were captured in relation to microclimatic parameters, particularly potential evaporation (Ep), which is a multiple meteorological factor and acts as an indicator of transpirational demand. The results indicated  that many genes were regulated by changes in temperature and Ep in both leaves and roots. Furthermore, the correlation between gene expression and meteorological factors differed significantly between the vegetative and reproductive stages. Since Ep triggers transpiration, we analyzed aquaporin gene expression, which is responsible for water transport, and found that many aquaporin genes in leaves were positively correlated with Ep throughout the growth period, whereas in roots, two plasma membrane intrinsic aquaporins, PIP2;4 and PIP2;5 were strongly correlated with Ep during reproductive growth. Other genes closely related to productivity, such as those involved in nutrient absorption and photosynthesis, exhibited different responses to meteorological factors at different growth stages. The stage-dependent shift in the microclimate response provides an important perspective on crop physiology in light of climate change.

Alternative strategy for driving voltage-oscillator in neocortex of rats

Information integration in the brain requires functional connectivity between local neural networks. Here, we investigated the interregional coupling mechanism from the viewpoint of oscillations using optical recording methods. Low-frequency electrical stimulation of rat neocortical slices in a caffeine-containing medium induced oscillatory activity between the primary visual cortex (Oc1) and medial secondary visual cortex (Oc2M), in which the oscillation generator was located in the Oc2M and was triggered by a feedforward signal. During to-and-fro oscillatory activity, neural excitation was marked in layer II/III. When the upper layer was disrupted between Oc1 and Oc2M, feedforward signals could propagate through the deep layer and switch on the oscillator in the Oc2M. When the lower layer was disrupted between Oc1 and Oc2M, feedforward signals could propagate through the upper layer and switch on the oscillator in the Oc2M. In the backward direction, neither the upper layer cut nor the lower layer cut disrupted the propagation of the oscillations. In all cases, the horizontal and vertical pathways were used as needed. Fluctuations in the oscillatory waveforms of the local field potential at the upper and lower layers in the Oc2M were reversed, suggesting that the oscillation originated between the two layers. Thus, the neocortex may work as a safety device for interregional communications in an alternative way to drive voltage oscillators in the neocortex.

In Planta Monitoring of Cold-Responsive Promoter Activity Reveals a Distinctive Photoperiodic Response in Cold Acclimation

Plant cold acclimation involves complicated pathways that integrate signals from temperature changes and light conditions. To understand plant responses to environmental signals in detail, molecular events that are regulated by temperature and light must be investigated at the whole-plant level in a nondestructive way. Using the promoter of COR15A connected to the luciferase reporter gene as a cold-responsive indicator, we developed an in planta monitoring system for gene expression under controlled temperature and photoperiod conditions. COR15A promoter activity was intensified by day-night cycles at 2�C, while its induction was abruptly suppressed in the dark at 8�C or higher, indicating a difference in responsiveness to photocycle between these two acclimation conditions. Freeze-thawing tests of whole plants proved that lower acclimation temperature resulted in higher tolerance to freezing, consistent with the temperature-dependent induction of COR15A. Inhibition of photosynthetic electron transport by 3-(3,4-dichlorophenyl)-1,1-dimethylurea eliminated the responsiveness to the day-night cycles at 2�C, indicating a possibility that the photosynthetic redox and/or the accumulation of photosynthates modulate COR15A responsiveness to photoperiod during cold acclimation, in addition to the well-known regulation by CBF (C-repeat binding factor) genes. These findings indicate that the cold-responsive promoter is regulated by distinctive mechanisms dependent on temperature and simultaneously affected by photocycle and photosynthesis.

Review of clinical studies on the nocebo effect

Objective: To review clinical studies on the nocebo effect. PubMed was searched for relevant clinical studies as well as studies on the relationship between the nocebo effect and genes. Data sources: A total of 35 clinical studies on the nocebo effect and one study on its relationship with genes were selected for review. All were conducted outside Japan. Results and conclusion: An increasing number of clinical studies on the nocebo effect are being published. The 36 studies selected for review were grouped into the following five categories: (1) studies of how differences in participant characteristics such as personality affect susceptibility to the nocebo effect, (2) studies of how differences in provision of information about side effects affect susceptibility to the nocebo effect, (3) studies of how nocebo conditioning affects susceptibility to the nocebo effect, (4) studies of nocebo response mechanisms, and (5) studies of the nocebo effect and genetic polymorphisms. The first four categories comprised 5, 19, 8, and 3 studies, respectively, and the fifth comprised 1 study. Most of the studies investigated how differences in the provision of information affect susceptibility to the nocebo effect. Few studies investigated individual differences in the nocebo effect (differences between responders and non-responders) or mechanisms of the nocebo effect.

Wide-field Single-photon Optical Recording in Brain Slices Using Voltage-sensitive Dye

Wide-field single photon voltage-sensitive dye (VSD) imaging of brain slice preparations is a useful tool to assess the functional connectivity in neural circuits. Due to the fractional change in the light signal, it has been difficult to use this method as a quantitative assay. This article describes special optics and slice handling systems, which render this technique stable and reliable. The present article demonstrates the slice handling, staining, and recording of the VSD-stained hippocampal slices in detail. The system maintains physiological conditions for a long time, with good staining, and prevents mechanical movements of the slice during the recordings. Moreover, it enables staining of slices with a small amount of the dye. The optics achieve high numerical aperture at low magnification, which allows recording of the VSD signal at the maximum frame rate of 10 kHz, with 100 pixel x 100-pixel spatial resolution. Due to the high frame rate and spatial resolution, this technique allows application of the post-recording filters that provide sufficient signal-to-noise ratio to assess the changes in neural circuits.

Network Plasticity Involved in the Spread of Neural Activity Within the Rhinal Cortices as Revealed by Voltage-Sensitive Dye Imaging in Mouse Brain Slices

The rhinal cortices, such as the perirhinal cortex (PC) and the entorhinal cortex (EC), are located within the bidirectional pathway between the neocortex and the hippocampus. Physiological studies indicate that the perirhinal transmission of neocortical inputs to the EC occurs at an extremely low probability, though many anatomical studies indicated strong connections exist in the pathway. Our previous study in rat brain slices indicated that an increase in excitability in deep layers of the PC/EC border initiated the neural activity transfer from the PC to the EC. In the present study, we hypothesized that such changes in network dynamics are not incidental observations but rather due to the plastic features of the perirhinal network, which links with the EC. To confirm this idea, we analyzed the network properties of neural transmission throughout the rhinal cortices and the plastic behavior of the network by performing a single-photon wide-field optical recording technique with a voltage-sensitive dye (VSD) in mouse brain slices of the PC, the EC, and the hippocampus. The low concentration of 4-aminopyridine (4-AP; 40 μM) enhanced neural activity in the PC, which eventually propagated to the EC via the deep layers of the PC/EC border. Interestingly, washout of 4-AP was unable to reverse entorhinal activation to the previous state. This change in the network property persisted for more than 1 h. This observation was not limited to the application of 4-AP. Burst stimulation to neurons in the perirhinal deep layers also induced the same change of network property. These results indicate the long-lasting modification of physiological connection between the PC and the EC, suggesting the existence of plasticity in the perirhinal-entorhinal network.

Relationship between medication adherence and glycemic control in Japanese patients with type 2 diabetes

A cross-sectional survey of 358 patients was conducted among type 2 diabetes patients recruited at medical institutions or via an online research company. Medication adherence was measured using the 8-item Morisky Medication Adherence Scale (MMAS-8). Univariate and multivariate regression analyses of glycosylated hemoglobin (HbA1c) were performed in addition to assessing demographic and disease characteristics and MMAS-8. In conclusion, medication adherence as measured by the MMAS-8 score independently contributes to altering the HbA1c level in the range of 1.12 %. The number of medications prescribed and insulin use are also related to HbA1c.

Overall Assay of Neuronal Signal Propagation Pattern With Long-Term Potentiation (LTP) in Hippocampal Slices From the CA1 Area With Fast Voltage-Sensitive Dye Imaging

Activity-dependent changes in the input-output (I-O) relationship of a neural circuit are central in the learning and memory function of the brain. To understand circuit-wide adjustments, optical imaging techniques to probe the membrane potential at every component of neurons, such as dendrites, axons and somas, in the circuit are essential. We have been developing fast voltage-sensitive dye (VSD) imaging methods for quantitative measurements, especially for single-photon wide-field optical imaging. The long-term continuous measurements needed to evaluate circuit-wide modifications require stable and quantitative long-term recordings. Here, we show that VSD imaging (VSDI) can be used to record changes in circuit activity in association with theta-burst stimulation (TBS)-induced long-term potentiation (LTP) of synaptic strength in the CA1 area. Our optics, together with the fast imaging system, enabled us to measure neuronal signals from the entire CA1 area at a maximum frame speed of 0.1 ms/frame every 60 s for over 12 h. We also introduced a method to evaluate circuit activity changes by mapping the variation in recordings from the CA1 area to coordinates defined by the morphology of CA1 pyramidal cells. The results clearly showed two types of spatial heterogeneity in LTP induction. The first heterogeneity is that LTP increased with distance from the stimulation site. The second heterogeneity is that LTP is higher in the stratum pyramidale (SP)-oriens region than in the stratum radiatum (SR). We also showed that the pattern of the heterogeneity changed according to the induction protocol, such as induction by TBS or high-frequency stimulation (HFS). We further demonstrated that part of the heterogeneity depends on the I-O response of the circuit elements. The results show the usefulness of VSDI in probing the function of hippocampal circuits.

Case report: Electron microscopic evaluation of bone from a patient treated with cinacalcet hydrochloride, maxacalcitol, and alfacalcidol for hyperparathyroid bone disease with secondary hyperparathyroidism

Evaluation of bone is of great importance in chronic kidney disease patients, as these patients are at an increased risk for fractures. We treated a hemodialysis patient suffering from hyperparathyroid bone disease with cinacalcet hydrochloride and concurrent administration of maxacalcitol and alfacalcidol for a year. Hyperparathyroid bone disease is characterized by cortical thinning, increased cortical porosity, reduced trabecular bone volume, and increased hypomineralized matrix volume, and there is little information to date about the effects of treatment with cinacalcet hydrochloride on the bone fragility in patients with hyperparathyroid bone disease. In the present study, histological and backscattered electron microscopic evaluation of this combination treatment revealed an excellent improvement of both bone volume and bone morphology. This treatment improved cortical thinning, cortical porosity, and trabecular thinning. Furthermore, the treatment also reduced hypomineralized matrix volume, indicative of improved mineralization by osteocytes. We speculate that the intermittent maxacalcitol administration may have effectively stimulated the vitamin D receptors expressed on osteocytes and osteoblasts, resulting in increased mineralization. Our approach for evaluating the bone in patients with chronic kidney disease by backscattered electron microscopy is novel.

Quasi-solid electrolyte: a thixotropic gel of imogolite and an ionic liquid

We report a quasi-solid electrolyte comprising a transparent thixotropic gel swelled by an ionic liquid that is formed by a framework of single-walled aluminosilicate cylindrical inorganic “imogolite” nanotubes.

Methodological Issues in Conducting Pilot Trials in Chronic Pain as Randomized, Double-blind, Placebo-controlled Studies

BACKGROUND

The efficacy of tapentadol extended release (ER) for managing chronic pain has been demonstrated in large-scale, randomized, controlled, phase 3 studies (N=318-1,030) in patients with chronic osteoarthritis (OA) pain, low back pain (LBP), and pain related to diabetic peripheral neuropathy (DPN), which led to registration in many regions, including the United States and Europe. 2 pilot 12-week, randomized, double-blind, placebo-controlled phase 2 studies of tapentadol ER for chronic pain (OA knee pain or LBP, n=91; DPN or peripheral herpetic neuralgia [PHN] pain; n=91) were conducted in Japan. These small exploratory studies were substantially underpowered compared with the registration trials.

METHODS

Patients in both studies were randomized (2:1) to tapentadol ER (25-250 mg) or placebo for 12 weeks (≤6-week titration plus maintenance periods).

RESULTS

For the primary efficacy endpoint (change in pain intensity from baseline to last week of treatment; last observation carried forward), both studies failed to differentiate between tapentadol ER and placebo; least-squares mean differences (95% confidence intervals) for tapentadol ER vs. placebo were -0.1 (-1.04, 0.80) in the OA/LBP study and -0.1 (-1.10, 0.99) in the DPN/PHN study. More than 80% of patients took concomitant analgesics during these studies. Tapentadol was well tolerated.

CONCLUSIONS

Both studies were associated with methodological issues, including populations with different disease entities, small sample sizes, use of concomitant analgesics, and possible placebo effect that may have led to the failure to differentiate between tapentadol ER and placebo.

Interplay between non-NMDA and NMDA receptor activation during oscillatory wave propagation: Analyses of caffeine-induced oscillations in the visual cortex of rats

Generation and propagation of oscillatory activities in cortical networks are important features of the brain. However, many issues related to oscillatory phenomena are unclear. We previously reported neocortical oscillation following caffeine treatment of rat brain slices. Input to the primary visual cortex (Oc1) generates N-methyl-d-aspartate (NMDA) receptor-dependent oscillations, and we proposed that the oscillatory signals originate in the secondary visual cortex (Oc2). Because non-NMDA and NMDA receptors cooperate in synaptic transmission, non-NMDA receptors may also play an important role in oscillatory activities. Here we investigated how non-NMDA receptor activities contribute to NMDA receptor-dependent oscillations by using optical recording methods. After induction of stable oscillations with caffeine application, blockade of NMDA receptors abolished the late stable oscillatory phase, but elicited 'hidden' non-NMDA receptor-dependent oscillation during the early depolarizing phase. An interesting finding is that the origin of the non-NMDA receptor-dependent oscillation moved from the Oc1, during the early phase, toward the origin of the NMDA receptor-dependent oscillation that is fixed in the Oc2. In addition, the frequency of the non-NMDA receptor-dependent oscillation was higher than that of the NMDA receptor-dependent oscillation. Thus, in one course of spatiotemporal oscillatory activities, the relative balance in receptor activities between non-NMDA and NMDA receptors gradually changes, and this may be due to the different kinetics of the two receptor types. These results suggest that interplay between the two receptor types in the areas of Oc1 and Oc2 may play an important role in oscillatory signal communication.

Paired Burst Stimulation Causes GABAA Receptor-Dependent Spike Firing Facilitation in CA1 of Rat Hippocampal Slices

The theta oscillation (4–8 Hz) is a pivotal form of oscillatory activity in the hippocampus that is intermittently concurrent with gamma (25–100 Hz) burst events. In in vitro preparation, a stimulation protocol that mimics the theta oscillation, theta burst stimulation (TBS), is used to induce long-term potentiation. Thus, TBS is thought to have a distinct role in the neural network of the hippocampal slice preparation. However, the specific mechanisms that make TBS induce such neural circuit modifications are still unknown. Using electrophysiology and voltage-sensitive dye imaging (VSDI), we have found that TBS induces augmentation of spike firing. The augmentation was apparent in the first couple of brief burst stimulation (100 Hz four pulses) on a TBS-train in a presence of NMDA receptor blocker (APV 50 μM). In this study, we focused on the characterizes of the NMDA independent augmentation caused by a pair of the brief burst stimulation (the first pair of the TBS; paired burst stimulation-PBS). We found that PBS enhanced membrane potential responses on VSDI signal and intracellular recordings while it was absent in the current recording under whole-cell clamp condition. The enhancement of the response accompanied the augmentation of excitatory postsynaptic potential (EPSP) to spike firing (E-S) coupling. The paired burst facilitation (PBF) reached a plateau when the number of the first burst stimulation (priming burst) exceeds three. The interval between the bursts of 150 ms resulted in the maximum PBF. Gabazine (a GABA_A receptor antagonist) abolished PBF. The threshold for spike generation of the postsynaptic cells measured with a current injection to cells was not lowered by the priming burst of PBS. These results indicate that PBS activates the GABAergic system to cause short-term E-S augmentation without raising postsynaptic excitability. We propose that a GABAergic system of area CA1 of the hippocampus produce the short-term E-S plasticity that could cause exaggerated spike-firing upon a theta-gamma activity distinctively, thus making the neural circuit of the CA1 act as a specific amplifier of the oscillation signal.

Arabidopsis dynamin-related protein 1E in sphingolipid-enriched plasma membrane domains is associated with the development of freezing tolerance

The freezing tolerance of Arabidopsis thaliana is enhanced by cold acclimation, resulting in changes in the compositions and function of the plasma membrane. Here, we show that a dynamin-related protein 1E (DRP1E), which is thought to function in the vesicle trafficking pathway in cells, is related to an increase in freezing tolerance during cold acclimation. DRP1E accumulated in sphingolipid and sterol-enriched plasma membrane domains after cold acclimation. Analysis of drp1e mutants clearly showed that DRP1E is required for full development of freezing tolerance after cold acclimation. DRP1E fused with green fluorescent protein was visible as small foci that overlapped with fluorescent dye-labelled plasma membrane, providing evidence that DRP1E localizes non-uniformly in specific areas of the plasma membrane. These results suggest that DRP1E accumulates in sphingolipid and sterol-enriched plasma membrane domains and plays a role in freezing tolerance development during cold acclimation.

WEE1 murine deficiency induces hyper-activation of APC/C and results in genomic instability and carcinogenesis

The tyrosine kinase WEE1 controls the timing of entry into mitosis in eukaryotes and its genetic deletion leads to pre-implantation lethality in mice. Here, we show that besides the premature mitotic entry phenotype, Wee1 mutant murine cells fail to complete mitosis properly and exhibit several additional defects that contribute to the deregulation of mitosis, allowing mutant cells to progress through mitosis at the expense of genomic integrity. WEE1 interacts with the anaphase promoting complex, functioning as a negative regulator, and the deletion of Wee1 results in hyper-activation of this complex. Mammary specific knockout mice overcome the DNA damage response pathway triggered by the mis-coordination of the cell cycle in mammary epithelial cells and heterozygote mice spontaneously develop mammary tumors. Thus, WEE1 functions as a haploinsufficient tumor suppressor that coordinates distinct cell division events to allow correct segregation of genetic information into daughter cells and maintain genome integrity.

A new nonscanning confocal microscopy module for functional voltage-sensitive dye and Ca2+ imaging of neuronal circuit activity

Recent advances in fluorescent confocal microscopy and voltage-sensitive and Ca(2+) dyes have vastly improved our ability to image neuronal circuits. However, existing confocal systems are not fast enough or too noisy for many live-cell functional imaging studies. Here, we describe and demonstrate the function of a novel, nonscanning confocal microscopy module. The optics, which are designed to fit the standard camera port of the Olympus BX51WI epifluorescent microscope, achieve a high signal-to-noise ratio (SNR) at high temporal resolution, making this configuration ideal for functional imaging of neuronal activities such as the voltage-sensitive dye (VSD) imaging. The optics employ fixed 100- × 100-pinhole arrays at the back focal plane (optical conjugation plane), above the tube lens of a usual upright microscope. The excitation light travels through these pinholes, and the fluorescence signal, emitted from subject, passes through corresponding pinholes before exciting the photodiodes of the imager: a 100- × 100-pixel metal-oxide semiconductor (MOS)-type pixel imager with each pixel corresponding to a single 100- × 100-μm photodiode. This design eliminated the need for a scanning device; therefore, acquisition rate of the imager (maximum rate of 10 kHz) is the only factor limiting acquisition speed. We tested the application of the system for VSD and Ca(2+) imaging of evoked neuronal responses on electrical stimuli in rat hippocampal slices. The results indicate that, at least for these applications, the new microscope maintains a high SNR at image acquisition rates of ≤0.3 ms per frame.

Relationship between glomerular filtration rate and plasma N-terminal pro B-type natriuretic peptide concentrations in dogs with chronic kidney disease

Plasma N-terminal pro B-type natriuretic peptide (NT-proBNP) concentrations increase in dogs with azotemia. However, the correlation between glomerular filtration rate (GFR) and NT-proBNP concentrations in dogs has not been evaluated. The objective of this study was to evaluate the correlation between GFR and plasma NT-proBNP concentrations in dogs with chronic kidney disease (CKD). In this retrospective cross-sectional study, plasma creatinine (Cre) and NT-proBNP concentrations, plasma iohexol clearance (PCio) values and blood pressure were measured in dogs with CKD. Dogs were classified according to PCio values into D group (dogs with decreased PCio values), and N group (dogs with normal PCio values). Dogs were further categorized on the basis of their systolic blood pressure and PCio values into NT-D group (normotensive dogs with decreased PCio values), NT-N group (normotensive dogs with normal PCio values), HT-D group (hypertensive dogs with decreased PCio values) and HT-N group (hypertensive dogs with normal PCio values). Significant correlations were observed between plasma NT-proBNP and Cre concentrations (r=0.360, P<0.05) and PCio values (r=-0.470, P<0.01). Plasma NT-proBNP concentrations were significantly higher in the D group than in the N group (P<0.001). Plasma NT-proBNP concentrations were significantly higher in the HT-D group than in the other three groups (P ≤ 0.007). No differences in plasma NT-proBNP concentrations were observed between the NT-D and HT-N groups (P=0.28). Plasma NT-proBNP concentrations were significantly lower in the NT-N group than in the other three groups (P ≤ 0.043). Our findings suggest that decreased GFR might be associated with increased plasma NT-proBNP concentrations in dogs, similar to that in humans. In addition, the complication of hypertension in CKD might be associated with further increases in plasma NT-proBNP concentrations. In conclusion, the effects of GFR and blood pressure on the plasma NT-proBNP concentration were small, but it could be necessary to consider the effects when this marker is used to evaluate canine cardiac disease.

Various patterns of traumatic triangular fibrocartilage complex tear

We demonstrate various patterns of traumatic triangular fibrocartilage complex (TFCC) tears including some atypical that cannot be categorized under Palmer's classification. TFCC traumatic tears in 173 wrists were examined arthroscopically or macroscopically and divided into disk tears (subdivided into four types: slit tear, flap tear, horizontal tear and tear within the distal radioulnar joint) and peripheral tears (subdivided into six types: ulnocarpal ligament tear, dorsal tear, radial tear, ulnar styloid tear, foveal tear and distal radioulnar ligament tear). Combinations of these types were found in 32 wrists. Wrist arthroscopy revealed various traumatic TFCC tears that do not come under Palmer's classification; therefore establishment of a new classification for traumatic TFCC tears seems to be warranted.

Relation of iodine-123 metaiodobenzylguanidine myocardial scintigraphy to endomyocardial biopsy findings in patients with dilated cardiomyopathy

BACKGROUND

Iodine-123 metaiodobenzylguanidine (123I-MIBG) concentrates in adrenergic neurons and has been developed for evaluation of the sympathetic nervous system. Recent studies have demonstrated that the normal heart is clearly visualized by 123I-MIBG cardiac scintigraphy, whereas abnormal 123I-MIBG myocardial uptake and washout have been demonstrated in patients after myocardial infarction and in patients with congestive cardiomyopathy, long QT syndrome, and ventricular tachycardia.

HYPOTHESIS

Based on evidence from recent studies, it can be hypothesized that 123I-MIBG uptake is related to histopathologic changes in the myocardium.

METHODS

The relation of 123I-MIBG uptake to the histologic findings for the heart was studied in 24 patients with dilated cardiomyopathy (DCM). The study group did not include patients with complicating disorders that primarily affect the adrenergic nervous system. The 123I-MIBG uptake was visually assigned one of four grades using the two criteria of the mean score for six regional uptake grades (mean score) and the global score obtained by visual evaluation of the entire image (global score). The 123I-MIBG uptake score was also determined for the region at which the biopsy specimen was obtained (biopsy region score). The histologic findings were evaluated by assigning one of four grades for each of the following five factors: myocyte hypertrophy, myocardial fibrotic change, myocyte degeneration and necrosis, mononuclear cell infiltration, and myocyte disarray. The sum for all grades was defined as the total score, and the global score was also assigned to the overall histologic findings.

RESULTS

All of the global, mean, and biopsy region scores for 123I-MIBG uptake correlated significantly with the global and total scores for the histologic findings. Among the histologic factors, myocyte degeneration showed score correlated with all global, mean, and biopsy region scores for the uptake. Myocyte hypertrophy was associated weakly with the 123I-MIBG uptake scores.

CONCLUSION

These results indicate that 123I-MIBG uptake imaging is associated with histopathologic abnormalities in patients with DCM.

Structure and functional analysis of wheat ICE (inducer of CBF expression) genes

Two different inducers of CBF expression (ICE1-like genes), TaICE41 and TaICE87, were isolated from a cDNA library prepared from cold-treated wheat aerial tissues. TaICE41 encodes a protein of 381 aa with a predicted MW of 39.5 kDa while TaICE87 encodes a protein of 443 aa with a predicted MW of 46.5 kDa. TaICE41 and TaICE87 share 46% identity while they share 50 and 47% identity with Arabidopsis AtICE1 respectively. Expression analysis revealed that mRNA accumulation was not altered by cold treatment suggesting that both genes are expressed constitutively. Gel mobility shift analysis showed that TaICE41 and TaICE87 bind to different MYC elements in the wheat TaCBFIVd-B9 promoter. Transient expression assays in Nicotiana benthamiana, showed that both TaICE proteins can activate TaCBFIVd-B9 transcription. The different affinities of TaICE41 and TaICE87 for MYC variants suggest that ICE binding specificity may be involved in the differential expression of wheat CBF genes. Furthermore, analysis of MYC elements demonstrates that a specific variant is present in the wheat CBF group IV that is associated with freezing tolerance. Overexpression of either TaICE41 or TaICE87 genes in Arabidopsis enhanced freezing tolerance only upon cold acclimation suggesting that other factors induced by low temperature are required for their activity. The increased freezing tolerance in transgenic Arabidopsis is associated with a higher expression of the cold responsive activators AtCBF2, AtCBF3, and of several cold-regulated genes.

Overexpression of TaVRN1 in Arabidopsis promotes early flowering and alters development

TaVRN1, a member of the APETALA1 (AP1) subfamily of MADS-box transcription factors, is a key gene that controls transition from vegetative to reproductive phase in wheat. The accumulation of TaVRN1 transcripts in winter wheat probably requires the down-regulation of TaVRT2, a MADS-box factor that binds and represses the TaVRN1 promoter, and of the flowering repressor TaVRN2. However, the molecular mechanisms by which TaVRN1 functions as an activator of phase transition is unknown. To address this, a combination of gene expression and functional studies was used. RNA in situ hybridization studies showed that TaVRN1 transcripts accumulate in all meristems and primordia associated with flower development. An interaction screen in yeast revealed that TaVRN1 interacts with several proteins involved in different processes of plant development such as transcription factors, kinases and a cyclophilin. Arabidopsis plants overexpressing TaVRN1 flower early and show various levels of modified plant architecture. The ectopic expression causes an overexpression of the AP1 and MAX4 genes, which are associated with flowering and auxin regulation, respectively. The induction of gene expression probably results from the binding of TaVRN1 to CArG motifs present on the AP1 and MAX4 promoters. In contrast, Arabidopsis plants that overexpress TaVRT2, which encodes a putative flowering repressor, show an opposite late flowering phenotype. Together, the data provide molecular evidence that TaVRN1 may have pleiotropic effects in various processes such as control of axillary bud growth, transition to flowering and development of floral organs.

TaVRT2 represses transcription of the wheat vernalization gene TaVRN1

In wheat, VRN1/TaVRN1 and VRN2/TaVRN2 determine the growth habit and flowering time. In addition, the MADS box transcription factor VEGETATIVE TO REPRODUCTIVE TRANSITION 2 (TaVRT2) is also associated with the vernalization response in a manner similar to TaVRN2. However, the molecular relationship between these three genes and their products is unknown. Using transient expression assays in Nicotiana benthamiana, we show that TaVRT2 acts as a repressor of TaVRN1 transcription. TaVRT2 binds the CArG motif in the TaVRN1 promoter and represses its activity in vivo. In contrast, TaVRN2 does not bind the TaVRN1 promoter and has no direct effect on its activity, but it can enhance the repression effect of TaVRT2. This suggests that a repressor complex regulates the expression of TaVRN1. In winter wheat, TaVRT2, TaVRN2 and TaVRN1 transcripts accumulate in the shoot apical meristem and young leaves, and temporal expression is consistent with TaVRT2 and TaVRN2 being repressors of floral transition, whereas TaVRN1 is an activator. Non-vernalized spring wheat grown under a short-day photoperiod accumulates TaVRT2 and shows a delay in flowering, suggesting that TaVRT2 is regulated independently by photoperiod and low temperature. The data presented suggest that TaVRT2, in association with TaVRN2, represses the transcription of TaVRN1.

Pathogenic mechanisms for parathyroid hyperplasia

Parathyroid hyperplasia is the cause of parathyroid gland enlargement in kidney disease (KD). Hypocalcemia, hyperphosphatemia, and vitamin D deficiency are critical contributors to the worsening of the hyperplastic parathyroid growth induced by KD. Reproduction of the features of human KD in the 5/6 nephrectomized rat model has shown that 80% of the mitogenic signals induced by KD in parathyroid cells that are aggravated by either high phosphate (P) or low calcium (Ca) diets occurred within 5 days after the onset of KD. Enhanced parathyroid expression of the potent growth promoter transforming growth factor alpha (TGFalpha) and its receptor, the epidermal growth factor receptor (EGFR), was identified as the main cause of parathyroid hyperplasia in experimental KD. Indeed, administration of highly specific EGFR-tyrosine kinase inhibitors (TKI), which block downstream signaling from TGFalpha-activated EGFR, completely prevented high P- and low Ca-induced parathyroid hyperplasia in early KD, as well as the severe progression of high P-induced parathyroid growth in established secondary hyperparathyroidism, the latter characterized by marked TGFalpha and EGFR overexpression in the parathyroid glands. More importantly, the suppression of signals downstream from TGFalpha binding to EGFR with EGFR-TKI treatment also revealed that TGFalpha self-upregulation in the parathyroid glands is the main determinant of the severity of the hyperplastic growth, and that enhanced TGFalpha activation of EGFR mediates the reduction in parathyroid vitamin D receptor levels thereby causing resistance to both the antiproliferative and parathyroid hormone-suppressive properties of calcitriol therapy.

Genistein inhibits Brca1 mutant tumor growth through activation of DNA damage checkpoints, cell cycle arrest, and mitotic catastrophe

Epidemiological studies revealed that amount of consumption of soy was inversely related to incidence of breast cancer. Genistein, the predominant isoflavone in soy, has been reported to reduce the incidence of breast cancer in animal models. To investigate whether genistein has a therapeutic effect on BRCA1-associated breast cancer, we treated Brca1 mutant mammary tumor cells with genistein. We showed that genistein treatment depleted the G1 population of cells, which was accompanied by an accumulation of cells at G2. Some genistein-treated cells entered mitosis; however, they exhibited chromosome abnormalities and maintained tetraploidy owing to abortive mitotic exit. A fraction of G2 cells underwent endoreduplication and became polyploid, which was accompanied by increased cell death through activating DNA damage response. Furthermore, our data indicated that Brca1 mutant cells were more sensitive to genistein than some other types of cancer cells, highlighting a good therapeutic potential of genistein for BRCA1-associated breast cancer.

Changes in coagulative and fibrinolytic activities in patients with intracranial hemorrhage

OBJECTIVE

To investigate whether any changes occur in the coagulative/fibrinolytic cascade in patients with subarachnoid hemorrhage (SAH) or hypertensive intracerebral hemorrhage (HICH).

DESIGN AND METHODS

Subjects included 143 patients with intracranial hemorrhage (SAH, n = 50; HICH, n = 82; ROSC-SAH [return of spontaneous circulation after cardiopulmonary arrest due to SAH], n = 11). Coagulative and fibrinolytic factors were measured in blood samples taken on admission.

RESULTS

The prothrombin fragment 1+2 level was significantly higher (p < 0.005) in SAH patients than in HICH patients. The fibrinolytic factors (plasmin alpha 2-plasmin inhibitor complex, D-dimer, or fibrinogen degradation products) in SAH and ROSC-SAH were both significantly higher than those in HICH, but the significance of difference was stronger in the case of ROSC-SAH (p < 0.05).

DISCUSSION

Both coagulative and fibrinolytic activities were altered after the onset of SAH. These results demonstrate that the coagulative/fibrinolytic cascade might be activated via different mechanisms in different types of stroke. It remains unclear, however, whether a significant alteration of the fibrinolytic cascade in patients with ROSC-SAH might be a nonspecific phenomenon attributable to the reperfusion after collapse.

Overexpression of aurora kinase A in mouse mammary epithelium induces genetic instability preceding mammary tumor formation

Aurora-A/STK15/BTAK, which encodes a centrosome-associated kinase, is amplified and overexpressed in multiple types of human tumors, including breast cancer. However, the causal relationship between overexpression of Aurora-A and tumorigenesis has not been fully established due to contradictory data obtained from different experimental systems. To investigate this, we generated a mouse strain that carries an MMTV-Aurora-A transgene. We showed that all the MMTV-Aurora-A mice displayed enhanced branch morphogenesis in the mammary gland and about 40% developed mammary tumors at 20 months of age. The tumor incidence was significantly increased in a p53(+/-) mutation background with about 70% MMTV-Aurora-A;p53(+/-) animals developed tumors at 18 months of age. Of note, overexpression of Aurora-A led to genetic instability, characterized by centrosome amplification, chromosome tetraploidization and premature sister chromatid segregation, at stages prior to tumor formation. Most notably, the severe chromosomal abnormality did not cause cell death owing to the activation of AKT pathway, including elevated levels of phosphorylated AKT and mammalian target of rapamycin, and nuclear accumulation of cyclin D1, which enabled continuous proliferation of the tetraploid cells. These data establish Aurora-A as an oncogene that causes malignant transformation through inducing genetic instability and activating oncogenic pathways such as AKT and its downstream signaling.

Ethyl esterification of docosahexaenoic acid in an organic solvent-free system with immobilized Candida antarctica lipase

Ethyl docosahexaenoate (EtDHA) is regarded as a potentially useful pharmaceutical substance on account of its beneficial physiological activities. We attempted the ethyl esterification of docosahexaenoic acid (DHA) in an organic solvent-free system using Candida antarctica lipase, which acts strongly on DHA and ethanol. Esterification of 88% was attained by shaking a mixture of DHA/ethanol (1:1, mol/mol) and 2 wt% immobilized C. antarctica lipase at 30 degrees C for 24 h. However, even in the presence of an excess amount of ethanol, the extent of esterification could not be raised above 90%. To attain a higher level of esterification, a two-step reaction was found to be effective. The first step was performed in a mixture of DHA/ethanol (1:1, mol/mol), and the reaction mixture was then dehydrated. In the second step, the resulting mixture was shaken at 30 degrees C for 24 h with 5 molar equivalents of ethanol against the remaining DHA using 2 wt% immobilized lipase. By means of this two-step procedure, 96% esterification was attained. Repetition of the first and second reactions showed that the immobilized lipase was reusable for at least 50 cycles. In addition, DHA remaining in the second-step reaction mixture was removed by a conventional alkali refining process, giving purified EtDHA with a high yield.

Enzymatic purification of polyunsaturated fatty acids

Polyunsaturated fatty acids (PUFAs) have various physiological functions. Of these, ethyl eicosapentaenoate is industrially purified and used as a medicine. Other PUFAs, such as docosahexaenoic acid (DHA), gamma-linolenic acid (GLA), and arachidonic acid (AA), are also expected to be used as pharmaceutical agents; however, their industrial purification processes have not been established. Because PUFAs are highly unstable against heat and oxidation, we attempted to purify them by taking advantage of their enzymatic reactions. When free fatty acids (FFAs) originating from PUFA-containing oil were selectively esterified with lauryl alcohol (LauOH) using a lipase acting on a desired PUFA very weakly, the PUFA was efficiently enriched in the FFA fraction. In addition, when selective alcoholysis of ethyl esters originating from PUFA-containing oil with LauOH was carried out, the PUFA ethyl ester (EtPUFA) was enriched to a desired purity in the unreacted ethyl ester fraction. These reaction mixtures contain LauOH, PUFA (EtPUFA), and lauryl esters, and their molecular weights are different from one another. Hence, PUFA or EtPUFA can be easily separated by conventional distillation. Selective esterification increased the purity of DHA, GLA, and n-6 PUFAs rich in AA to 91, 98, and 96 wt%, respectively. Selective alcoholysis was also effective for increasing the purity of ethyl docosahexaenoate to 90 wt%.

Cervical intervertebral disc injury during simulated frontal impact

Cervical disc injury due to frontal impact has been observed in both clinical and biomechanical investigations; however, there is a lack of data that elucidate the mechanisms of disc injury during these collisions. The goals of the current study were to determine the peak dynamic disc annular tissue strain and disc shear strain during simulated frontal impact of the whole human cervical spine model with muscle force replication at 4 g, 6 g, 8 g and 10 g horizontal accelerations of the T1 vertebra. These data were compared with those obtained during physiological loading, and with previously reported rear impact data. Peak disc shear strain and peak annular tissue strain during frontal impact exceeded (p<0.05) corresponding physiological limits at the C2-C3 intervertebral level, beginning at 4 g and 6 g, respectively. These subsequently spread throughout the entire cervical spine at 10 g, with the exception of C4-C5. The C5-C6 intervertebral level was at high risk for injury during both frontal and rear impacts, while during frontal impact, in addition to C5-C6, subfailure injuries were likely at superior intervertebral levels, including C2-C3. The disc injuries occurred at lower impact accelerations during rear impact as compared with frontal impact. The subfailure injuries of the cervical intervertebral disc that occur during frontal impact may lead to the chronic symptoms reported by patients, such as head and neck pain.

Clinical success of Neoral absorption profile

We investigated the clinical benefits of cyclosporine microemulsion preconcentrate (CyA-MEPC; Neoral) in 16 de novo renal transplant recipients. The dose of CyA-MEPC was managed from AUC(0-4h), with serial target values of AUC(0-4h) at 5000-->4000-->3000-->2000 ng. hr/mL. The frequency of acute rejection episodes was 25%. The decreased renal function reached a low value of 12.5%, and creatinine was stable. Therefore, setting the target AUC(0-4h) value in the early phase at 5000 ng.hr/mL is an effective strategy to prevent acute rejection episodes. The single dose of Neoral given immediately after the renal transplant was 6 mg/kg (making a daily dose of 12 mg/kg). Thereafter, the dose-normalized AUC(0-4h) was set at a constant value to 4 weeks posttransplant. At week 4, the single dose was decreased to 4 mg/kg twice daily (a daily dose of 8 mg/kg). From these studies a daily dose of 12 mg/kg is suggested to be the appropriate amount for the first dose immediately after transplant. The renal biopsy performed at 6 months posttransplant showed neither cyclosporine-induced renal impairments, nor findings of chronic rejection, suggesting that 2000 ng.hr/mL is an appropriate target AUC(0-4h) value in the maintenance phase. These results suggest that it is possible to set the target value of C2 monitoring in the maintenance phase to a value slightly lower than that proposed from other studies.

DeltaFosB, but not FosB, induces delayed apoptosis independent of cell proliferation in the Rat1a embryo cell line

The fates of Rat1a cells expressing FosB and DeltaFosB as fusion proteins (ER-FosB, ER-DeltaFosB) with the ligand binding domain of human estrogen receptor were examined. The binding of estrogen to the fusion proteins resulted in their nuclear translocation and triggered cell proliferation, and thereafter delayed cell death was observed only in cells expressing ER-DeltaFosB. The proliferation of Rat1a cells, but not cell death triggered by ER-DeltaFosB, was completely abolished by butyrolactone I, an inhibitor of cycline-dependent kinases, and was partly suppressed by antisense oligonucleotides against galectin-1, whose expression is induced after estrogen administration. The cell death was accompanied by the activation of caspase-3 and -9, the fragmentation of the nuclear genome and cytochrome c release from the mitochondria, and was suppressed by zDEVD-fmk and zLEHD-fmk but not zIETD-fmk. The cell death was not suppressed by exogenous His-PTD-Bcl-x(L) at all, suggesting involvement of a Bcl-x(L)-resistant pathway for cytochrome c release.

Optical imaging of long-lasting depolarization on burst stimulation in area CA1 of rat hippocampal slices

Postsynaptic depolarization of dendrites paired with spike generation at the soma is considered to be a central mechanism of long-term potentiation (LTP) induction and a prime example of a Hebbian synapse. This pairing, however, has never been actually demonstrated on tetanic stimulation. Optical imaging of neural activity with a voltage-sensitive dye (VSD) is one potentially suitable method for examining this pairing. It is possible with optical recording to examine simultaneously the excitation of postsynaptic neurons at multiple sites. Thus the pairing of spike generation at the soma and dendritic depolarization can be examined with population level optical recording in highly laminar structures such as the hippocampal slice preparation. For example, one can correlate the optical signals obtained from cell layers with the activity of the soma, and, similarly, optical signals from stratum radiatum can be correlated with the activity of the apical dendrite, even though one cannot calibrate the optical signals in terms of actual membrane potential. Using the VSD aminonaphthylethenylpyridinium in rat hippocampal slices, we aimed to examine the pairing. Standard tetanic stimulation (100 Hz, 1 s) that elicited LTP in the field excitatory postsynaptic potential (fEPSP) resulted in a long-lasting depolarizing optical signal (about 2 s) that spread progressively along the known input pathway of CA1. The time course of this long-lasting depolarization was similar to that recorded intracellularly and to that reflected in the fEPSP. The long-lasting depolarization was insensitive to D,L-2-amino-5-phosphonovaleric acid (D,L-APV, 50 microM), but D,L-APV inhibited the induction of LTP; this allowed us to increase the signal-to-noise ratio of the optical signal by averaging several trials. Using this improved optical signal, we confirmed that postsynaptic cells practically "missed" spikes during tetanic stimulation in most parts of CA1, which had been suggested in the intracellular recordings. Intracellular recordings revealed a 23% reduction in input resistance, which might explain the failed spike generation at the soma via shunting. A steep spatial convergence of the depolarization along the transverse axis of area CA1 was observed. In contrast to the response resulting from a standard 100-Hz tetanus, broader activation, and paired depolarization with somatic spikes was observed on theta-burst stimulation. Overall we concluded that postsynaptic spike generation, at least in synchronous form, has less effect on LTP induction with standard tetanic stimulation, while theta-burst tetanic stimulation can elicit pairing of dendritic depolarization and somatic discharge.