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Photoacoustic (PA) imaging (PAI) has been shown to be a promising tool for non-invasive blood vessel imaging. A PAI system comprising a hemispherical detector array (HDA) has been reported previously as a method providing high morphological reproducibility. However, further improvements in diagnostic capability will require improving the image quality of PAI and fusing functional and morphological imaging. Our newly developed PAI system prototype not only enhances the PA image resolution but also acquires ultrasonic (US) B-mode images at continuous positions in the same coordinate axes. In addition, the pulse-to-pulse alternating laser irradiation shortens the measurement time difference between two wavelengths. We scanned extremities and breasts in an imaging region 140 mm in diameter and obtained 3D-PA images of fine blood vessels, including arterioles and venules. We could estimate whether a vessel was an artery or a vein by using the S-factor obtained from the PA images at two wavelengths, which corresponds approximately to the haemoglobin oxygen saturation. Furthermore, we observed tumour-related blood vessels around breast tumours with unprecedented resolution. In the future, clinical studies with our new PAI system will help to elucidate various mechanisms of vascular-associated diseases and events., 光超音波イメージングで人体の精細な動静脈像を得ることに成功 --腫瘍血管の解析や再建手術への応用に期待--. 京都大学プレスリリース. 2018-10-25.

A large number of the steel sheet pile canal has been widely used in rural areas. In recent years, the relationship between the durability and the corrosion of the steel sheet pile has been discussed as a technical problem. In this study, development of conservation method for corroded steel sheet pile canal is going to be performed, applying steel sheet pile - concrete composite. The experiments were conducted in model tests and existing structure. In the monitoring, the bending properties of composite are evaluated based on displacement measurement and AE method. Thus, the mechanical properties of composite could be evaluated by comparing a moment with a maximum displacement. And, the AE generation behavior is correlated with fracture process in bending test. The experiment results, the covering effect of concrete is quantitatively estimated.鋼矢板水路は、農村地域に広く普及している。近年、鋼矢板の長期耐久性と鋼材腐食との関連が技術的課題として議論されている。本研究では、腐食した鋼矢板水路の保護工法の開発のため、鋼矢板-コンクリート複合材の適用性を検討した。実験的検討は、モデル試験と実大試験を実施した。鋼矢板-コンクリート複合材の曲げ特性の評価は、変位計測とAE法を用いた。結果、複合材の曲げ特性は、最大変位量と作用モーメントの関係から評価することができた。そして、AE発生挙動は、曲げ載荷過程における破壊挙動との相関が確認できた。本試験結果から、鋼矢板表面にコンクリート被覆を施すことの有効性を定量的に評価できたものと推察された。

AC power driven electronic products such as PCs, printers, copiers also radiate electromagnetic disturbances from their AC power cable not only from their chassis. The strength of the radiated emission from the AC power cable is affected by the impedance-about-ground of the EUT power feeding port of the radiated emission testing laboratory. However, the radiated emission from the AC power cable varies depending on the testing laboratories by the impedance-about-ground of EUT power feeding port, and the impedance-about-ground is not specified in the standards. To evaluate the effects of the impedance-about-ground of the EUT power feeding port of radiated emission testing laboratories by means of inter-laboratory comparison program (proficiency test), it cannot be evaluated precisely by using artifact that do not have AC power cable. Moreover, the influences of the impedance-about-ground cannot be solved by means of the site attenuation or other propagation analysis. We developed artifact that driven by AC power (having AC power cable) and the artifact was used for inter-laboratory comparison program organized by VLAC in past 10 years. The artifact brought significant merit for the practical inter-laboratory comparison for the purpose of improvement of reproducibility of radiated emission test.

The Pyk2 tyrosine kinase can be activated by both calcium-dependent and calcium-independent mechanisms. Exposure to moderate hypoxia (5% O 2 ) induced a rapid and persistent tyrosine phosphorylation of Pyk2 in pheochromocytoma (PC12) cells. Hypoxia and KCl-depolarization increased the phosphotyrosine content of Pyk2 by twofold and fourfold, respectively. Both of these effects were abolished in the absence of extracellular calcium. There was a modest activation of MAPK in parallel with the onset of Pyk2 phosphorylation. However, there was no detectable activation of either JNK or c-src, two other known downstream targets of Pyk2. Thus, exposure to hypoxia may selectively target specific subsets of Pyk2 signalling pathways.

Carotid artery stenting (CAS) has been developed in recent years as an alternative to carotid endarterectomy (CEA). We report our clinical experience of CAS and evaluate the feasibility and efficacy of this treatment. Since 1997 Feb, 237 patients (199 male, aged 50-85, mean 67.5), 235 carotid artery stenosis (109 symptomatic, 126 asymptomatic), 5 aortitis, 1 FMD, and 6 dissecting were treated with 259 endovascular stenting procedures. Our method in now is as follows;under local anesthesia, transfemoral approach, using guiding catheter, pre-dilation with low profile 3mm PTA balloon with. 014" long wire, and self-expandable stent deployment. Since 1998 Dec, we have used our originally made distal balloon protective system in post PTA. Procedural success was 99.2%, and complications occurred in 2 (0.77%) major and 6 (2.3%) minor stroke without mortality. Restenosis occurred in 12/155 (7.7%) of F/U angiography, 6-50 months after treatment. No complication occurred in re-treatment. Our results indicate that carotid stenting may well offer a similar safety profile and efficacy to those of carotid endarterectomy. The future status of carotid artery stenting will be determined with randomized trials and improvement in devices, technique and safety.

We investigated the effect of hypoxia on glutamate metabolism and uptake in rat pheochromocytoma (PC12) cells. Various key enzymes relevant to glutamate production, metabolism and transport were coordinately regulated by hypoxia. PC12 cells express two glutamate-metabolizing enzymes, glutamine synthetase (GS) and glutamate decarboxylase (GAD), as well as the glutamate-producing enzyme, phosphate-activated glutaminase (PAG). Exposure to hypoxia (1% O2) for 6 h or longer increased expression of GS mRNA and protein and enhanced GS enzymatic activity. In contrast, hypoxia caused a significant decrease in expression of PAG mRNA and protein, and also decreased PAG activity. In addition, hypoxia led to an increase in GAD65 and GAD67 protein levels and GAD enzymatic activity. PC12 cells express three Na+-dependent glutamate transporters; EAAC1, GLT-1 and GLAST. Hypoxia increased EAAC1 and GLT-1 protein levels, but had no effect on GLAST. Chronic hypoxia significantly enhanced the Na+-dependent component of glutamate transport. Furthermore, chronic hypoxia decreased cellular content of glutamate, but increased that of glutamine. Taken together, the hypoxia-induced changes in enzymes related to glutamate metabolism and transport are consistent with a decrease in the extracellular concentration of glutamate. This may have a role in protecting PC12 cells from the cytotoxic effects of glutamate during chronic hypoxia.

The present study was undertaken to determine whether rat carotid bodies express adenosine (Ado) A2A receptors and whether this receptor is involved in the cellular response to hypoxia. Our results demonstrate that rat carotid bodies express the A2A and A2B Ado receptor mRNAs but not the A1 or A3 receptor mRNAs as determined by reverse transcriptase-polymerase chain reaction. In situ hybridization confirmed the expression of the A2A receptor mRNA. Immunohistochemical studies further showed that the A2A receptor is expressed in the carotid body and that it is colocalized with tyrosine hydroxylase in type I cells. Whole cell voltage-clamp studies using isolated type I cells showed that Ado inhibited the voltage-dependent Ca2+ currents and that this inhibition was abolished by the selective A2A receptor antagonist ZM-241385. Ca2+ imaging studies using fura 2 revealed that exposure to severe hypoxia induced elevation of intracellular Ca2+ concentration ([Ca2+]i) in type I cells and that extracellularly applied Ado significantly attenuated the hypoxia-induced elevation of [Ca2+]i. Taken together, our findings indicate that A2A receptors are present in type I cells and that activation of A2Areceptors modulates Ca2+ accumulation during hypoxia. This mechanism may play a role in regulating intracellular Ca2+homeostasis and cellular excitability during hypoxia.

Objectives: We have investigated the effects and outcome from grafting the right internal thoracic artery to the left anterior descending artery in coronary artery bypass grafting.Methods: We analyzed the findings in 185 patients who underwent coronary artery bypass grafting involving right internal thoracic artery-left anterior descending artery bypass. The survival rate, cardiac events related to the right internal thoracic artery-left anterior descending artery graft, and graft patency were investigated. In cardiac catheterization, the production of nitric oxide from the endothelium of the internal thoracic artery was measured as the plasma nitrite and nitrate levels by the Griess reaction. The reactions to acetylcholine infusion (5 μg) in the right internal thoracic artery (n = 4) were compared to those in the left internal thoracic artery (n = 9) grafts.Results: The hospital mortality rate was 0.5%. The actuarial survival rate at 11 years after operation was 98.81%. The rate of freedom from cardiac events at 11 years after operation was 92.08%. The rate of patency of the right internal thoracic artery-left anterior descending artery was 97.0% in 133 patients. Nitric oxide production was calculated as (total nitrite plus nitrate production in response to stimulation by acetylcholine-total nitrite plus nitrate level before acetylcholine load) / (total nitrite plus nitrate level before acetylcholine load). There was no significant difference in changes in plasma concentration in response to acetylcholine stimulation between the right internal thoracic artery-left anterior descending artery and left internal thoracic artery-left anterior descending artery groups (20 ± 29% versus 5 ± 10%).Conclusions: The right internal thoracic artery-left anterior descending artery grafts exhibited good patency and release of nitric oxide in response to acetylcholine loading, similar to left internal thoracic artery-left anterior descending artery grafts.

The purpose of this study was to examine the regulation of adenosine A2A receptor (A2AR) gene expression during hypoxia in pheochromocytoma (PC12) cells. Northern blot analysis revealed that the A2AR mRNA level was substantially increased after a 3-h exposure to hypoxia (5% O2), which reached a peak at 12 h. Immunoblot analysis showed that the A2AR protein level was also increased during hypoxia. Inhibition of de novo protein synthesis blocked A2AR induction by hypoxia. In addition, removal of extracellular free Ca2+, chelation of intracellular free Ca2+, and pretreatment with protein kinase C inhibitors prevented A2AR induction by hypoxia. Moreover, depletion of protein kinase C activity by prolonged treatment with phorbol 12-myristate 13-acetate significantly inhibited the hypoxic induction of A2AR. A2AR antagonists led to a significant enhancement of A2AR mRNA levels during hypoxia, whereas A2AR agonists caused down-regulation of A2AR expression during hypoxia. This suggests that A2AR regulates its own expression during hypoxia by feedback mechanisms. We further found that activation of A2AR enhances cell viability during hypoxia and also inhibits vascular endothelial growth factor expression in PC12 cells. Thus, increased expression of A2AR during hypoxia might protect cells against hypoxia and may act to inhibit hypoxia-induced angiogenic activity mediated by vascular endothelial growth factor.

1. The present study was undertaken to determine the role of adenosine in mediating the cellular responses to hypoxia in rat phaeochromocytoma (PC12) cells, an oxygen-sensitive clonal cell line. 2. Reverse transcriptase polymerase chain reaction studies revealed that PC12 cells express adenosine deaminase (the first catalysing enzyme of adenosine degradation) and the A2A and A2B adenosine receptors, but not the A1 or A3 adenosine receptors. 3. Whole-cell current- and voltage-clamp experiments showed that adenosine attenuated the hypoxia-induced membrane depolarization. The hypoxia-induced suppression of the voltage-sensitive potassium current (IK(V)) was markedly reduced by adenosine. Furthermore, extracellularly applied adenosine increased the peak amplitudes of IK(V) in a concentration-dependent manner. This increase was blocked by pretreatment not only with a non-specific adenosine receptor antagonist, 8-phenyltheophylline (8-PT), but also with a selective A2A receptor antagonist, ZM241385. 4. Ca2+ imaging studies using fura-2 acetoxymethyl ester (fura-2 AM) revealed that the increase in intracellular free Ca2+ during hypoxic exposure was attenuated significantly by adenosine. Voltage-clamp studies showed that adenosine inhibited the voltage-dependent Ca2+ currents (ICa) in a concentration-dependent fashion. This inhibition was also abolished by both 8-PT and ZM241385. 5. The modulation of both IK(V) and ICa by adenosine was prevented by intracellular application of an inhibitor of protein kinase A (PKA), PKA inhibitor fragment (6-22) amide. In addition, the effect of adenosine on either IK(V) or ICa was absent in PKA-deficient PC12 cells. 6. These results indicate that the modulatory effects of adenosine on the hypoxia-induced membrane responses of PC12 cells are likely to be mediated via activation of the A2A receptor, and that the PKA pathway is required for these modulatory actions. We propose that this modulation serves to regulate membrane excitability in PC12 cells and possibly other oxygen-sensitive cells during hypoxia.

Regulation of gene expression for tyrosine hydroxylase in oxygen sensitive cells by hypoxia. Carotid body type I cells and the O 2 -sensitive pheochromocytoma (PC12) cells release dopamine during hypoxia. Reduced O 2 tension causes inhibition of an outward rectifying the O 2 -sensitive potassium (K) channel in the O 2 -sensitive pheochromocytoma (PC12) cell line, which leads to membrane depolarization and increased intracellular free Ca 2+ . We found that removal of Ca 2+ from the extracellular milieu, inhibition of voltage-dependent Ca 2+ channels, and chelation of intracellular Ca 2+ prevents full activation of the TH gene expression during hypoxia. These findings suggest that membrane depolarization and regulation of intracellular free Ca 2+ are critical signal transduction events that regulate expression of the TH gene in PC12 cells during hypoxia. Gene expression of tyrosine hydroxylase (TH), the rate-limiting enzyme in the biosynthesis of dopamine, is stimulated by reduced O 2 tension in both type I cells and PC12 cells. The increase in TH gene expression in PC12 cells during hypoxia is due to increases in both the rate of transcription and mRNA stability. Analysis of reporter-gene constructs revealed that increased transcription of the TH gene during hypoxia is regulated by a region of the proximal promoter that extends from −284 to −150 bases, relative to the transcription start site. This region of the gene contains a number of cis -acting regulatory elements including AP1, AP2 and hypoxia-inducible factor (HIF-1). Competition assays revealed that hypoxia-induced binding occurs at both the AP1 and HIF-1 sites. Results from super-shift and shift Western assays showed that a heterodimer consisting of c- Fos and JunB binds to the API site during hypoxia. Mutagenesis experiments revealed that the AP1 site is required for increased transcription of the TH gene during hypoxia. We also found that the genes that encode the c- Fos and JunB transcription factor proteins are regulated by reduced O 2 tension.

We have fabricated organic electroluminescent devices with poly ( p -phenylene) as a hole-transporting layer, and with tris (8-hydroxy-quinoline) aluminum as an emitting layer by vacuum deposition. As a result, it is found that the deposited PPP film is an effective film as a hole transport layer, and that the characteristic of these devices changes remarkably with substrate temperature at vacuum deposition.

Site VSWR to evaluate radiated emission test sites above 1 GHz is defined by CISPR 16-1-4. However, the Site VSWR has been specified without theoretical basis and its limit was also changed several times without reasonable grounds. We confirmed that site attenuation is suitable for evaluation of radiated emission test sites above 1 GHz and we devised a method to evaluate radiated emission test sites above 1 GHz as free-space by means of wave propagation measurements using a conical dipole antenna that was developed the idea of site attenuation measurement. We confirmed the advantage and practical usefulness of the method using propagation loss of different polarization to use evaluation for radiated emission test sites above 1 GHz.

We have constructed a prototype photoacoustic mammography system (PAM-02) capable of simultaneously acquiring photoacoustic (PA) and ultrasound (US) images. Each PA, US, and fused PA/US image can be acquired over a wide area of the breast using the scanning module of a US transducer, a PA detector, and optical prisms. The resolution of the PA images exhibits improvement from 2 to 1 mm compared to images acquired using our previous prototype. The maximum scan area of PAM-02 is 90 mm along the horizontal axis and 150 mm along the vertical axis. In a phantom experiment, the available depth was at least 45 mm. A representative example of the application of the PAM-02 prototype in clinical research at Kyoto University is presented and shows S-factor images, which are considered an approximation parameter related to hemoglobin saturation of tumor-related blood vessels. We confirmed the applicability of the system for anatomical and biological research.

Cortical spreading depression (CSD) was induced in male Wistar rats by applying 2 M KCl to the frontal cortex of one hemisphere for 2 h. Saline was applied to the contralateral cortex in the same manner. Following recovery for 24 h, bilateral forebrain ischemia was induced for 6 min, and the animals were permitted to survive for 6 days for assessment of histopathology. The number of necrotic neurons was counted in the cerebral cortex, striatum, and hippocampus of both hemispheres. In separate sets of animals, the effects of KCl application on cortical direct current (DC) potential and regional expression of c- fos mRNA and 72-kDa heat shock protein (hsp72) mRNA were determined. Forebrain ischemia induced selective neuronal necrosis in both hemispheres, but the number of necrotic neurons in the cerebral cortex ipsilateral to the application of KCl was significantly smaller than that in the contralateral cortex ( p < 0.02, Wilcoxon signed rank test, n = 7). In the striatum and hippocampus, there were no significant differences in neuronal necrosis between hemispheres. Application of KCl for 2 h induced 11 ± 2 (mean ± SD, n = 5) negative deflections of DC potential in the ipsilateral cortex; none were detected in the contralateral cortex. Widespread expression of c- fos mRNA was evident in the ipsilateral cortex, while hsp72 mRNA expression was restricted to the KCl application site. The present results demonstrate that CSD induces tolerance of cortical neurons to ischemia by mechanisms unrelated to hsp72.

Site VSWR to evaluate radiated emission test sites above 1 GHz is defined by CISPR 16-1-4. However, the Site VSWR has been specified without theoretical basis and its limit was also changed several times without reasonable grounds. We confirmed that site attenuation is suitable for evaluation of radiated emission test sites above 1 GHz using a conical dipole antenna. The coherence and the continuity of site evaluation method from below 1 GHz are maintained. [1][2][3] In this paper, we propose a new method to evaluate radiated emission test sites above 1 GHz as free-space by means of wave propagation measurements using a conical dipole antenna.

We developed a conical dipole antenna that operates in the frequency range of 1 GHz to 6 GHz as a broadband antenna. In this paper we describe site attenuation measurements in the 1 GHz to 6 GHz frequency range using this antenna for the CSA (Classical/Conventional Site Attenuation) and NSA (Normalized Site Attenuation) methods, and we verified that measuring site attenuation using this conical dipole antenna is an appropriate method for evaluating radiated emission test sites above 1 GHz. Site attenuation is more sensitive for detecting unwanted reflection waves than Site VSWR. Therefore site attenuation is superior to Site VSWR for use in site validity evaluation. Site attenuation in the 30 MHz to 1000 MHz range has been the standard method with logical underpinnings used for more than 20 years and is recognized by CISPR and many countries as the national standard. The method proposed above permits the same method of evaluation of the suitability of radiated emission test sites to be extended to the 1 GHz to 6 GHz frequency range; coherence and continuity are maintained, which we believe to be highly significant.

A 21-yr-old man with multiple pulmonary AV fistulae presented with moderate hypoxemia with chronic hyperventilation, which continued even after sufficient oxygenation by 100% O2 inhalation. The infusion of aminophylline, an adenosine receptor blocker, not only increased PaCO2 from 35 to 39 mm Hg but also depressed the magnitude of hypoxic ventilatory response (HVR). After a surgical removal of the major fistulae, PaCO2 increased to 42 mm Hg. At this time, aminophylline increased the resting ventilation and slightly augmented the HVR value, which was opposite to the findings of preoperation. Dipyridamole, which potentiates endogenous adenosine by inhibiting its cellular uptake, increased the magnitude of HVR both before and after the operation. We propose that the hyperventilation observed in this case can at least in part be attributed to the ventilatory stimulation by endogenous adenosine, which presumably passed through the fistulae without being metabolized in the pulmonary circulation.

In this study, we characterized a newly developed imaging system, "dual illumination mode photoacoustic tomography (PAT) system". The PAT system can simultaneously or separately illuminate biological tissues from a forward and backward direction toward an array transducer. The shape of the custom-made transducer is rectangular, which allows direct illumination of tissue surfaces in front of the array transducer through a holding plate from the backward direction. The transducer frequency was designed at 1 MHz by considering the trade-off relationship between ultrasound attenuation and image resolution. A Ti:Sa laser optically pumped with a Q-switched Nd:YAG laser, having a tunable wavelength of 700 to 900 nm, was chosen for deep light penetration in tissues. The laser light was sufficiently expanded and homogenized to keep the level of laser-pulse fluence on the sample surface under the ANSI safety limit. System performance was tested with phantoms. The results of our study showed that the system visualized all the absorbers embedded in a 50-mm-thick tissue-mimicking phantom with a lateral resolution of 2~3 mm.

Using a brief transient ischemic model, we examined changes in regional tissue calcium content and energy metabolism in the hippocampus. In the CA1 region, tissue calcium ions began to increase 24 h after reperfusion, accompanied by changes in tissue pH and ATP. In the CA3 region, energy metabolism remained unchanged for 72 h after reperfusion, and the calcium pool was first noted 24 h after reperfusion, while tissue calcium ions began to increase 48 h after reperfusion. These results suggest that the neurons in the CA3 region seem to survive because of the well-preserved metabolic function to cope with excessive calcium ions.

To investigate regional changes in calcium ion concentrations, we developed a new histochemical method using aequorin, a calcium ion-sensitive photoprotein. In this method, reagent film containing aequorin was made and an unfixed slice of frozen brain 16 μm thick was placed on it. Tissue calcium ions permeated the reagent layer and the bioluminescence of aequorin-calcium ions was recorded photographically with high spatial resolution. There was a close linear relationship ( r = 0.903) between the optical density of the bioluminescent images and the logarithmic values of the tissue calcium ion concentration. Using this method, we could visualize the regional tissue calcium ion distribution in pathological states in rat brains.

This is the first report suggesting a causal relationship between acute respiratory distress syndrome and Hericium erinaceum extract, which is commercialized as a diet food. A 63-year-old man was admitted to our hospital for intensive care of severe acute respiratory failure with diffuse infiltration in both lungs. Bronchoalveolar lavage fluid revealed a high percentage of lymphocytes. Lymphocyte stimulation test showed a strong reactivity against extract formulation of Hericium erinaceum (Yamabushitake), which he had taken four months before onset. He recovered with successful steroid pulse therapy under mechanical ventilation. Concentrations of surfactant protein (SP)-A and SP-D in sera reflected the clinical features.

To gain insight into the pathogenesis of diabetic cardiomyopathy, we investigated cardiac function in terms of the coupling of left ventricular mechanical work and the energetics in Otsuka Long-Evans Tokushima Fatty rats, which are well known as a model of type 2 diabetes mellitus (DM). Neither left ventricular systolic function and mean coronary flow nor coronary flow reserve differed even in late DM rats. The amount of oxygen required for mechanical work and contraction was unaltered, although myosin isozyme was finally transformed from V1 to V3. The maximum pacing rate was decreased from 300 to 240 beats/min, and the left ventricular relaxation rate was significantly ( P < 0.05) slower only in late DM rats, resulting in decreased oxygen consumption per minute for total Ca2+ handling in excitation-contraction coupling mainly consumed by sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA2) without significant changes in basal metabolism or in mitochondrial oxidative phosphorylation. The protein level of SERCA2 in membranes was significantly ( P < 0.001) lower in severe DM rats. We conclude that the only lusitropic dysfunction due to the depressed expression of SERCA2 is related to generating diabetic cardiomyopathy even in the present type 2 diabetic rats.

The aim of the present study was to examine the mechanisms of Ca2+ overload-induced contractile dysfunction in rat hearts independent of ischemia and acidosis. Experiments were performed on 30 excised cross-circulated rat heart preparations. After hearts were exposed to high Ca2+, there was a contractile failure associated with a parallel downward shift of the linear relation between myocardial O2 consumption per beat and systolic pressure-volume area (index of a total mechanical energy per beat) in left ventricles from all seven hearts that underwent the protocol. This result suggested a decrease in O2consumption for total Ca2+ handling in excitation-contraction coupling. In the hearts that underwent the high Ca2+ protocol and had contractile failure, we found marked proteolysis of a cytoskeleton protein, α-fodrin, whereas other proteins were unaffected. A calpain inhibitor suppressed the contractile failure by high Ca2+, the decrease in O2 consumption for total Ca2+ handling, and membrane α-fodrin degradation. We conclude that the exposure to high Ca2+ may induce contractile dysfunction possibly by suppressing total Ca2+ handling in excitation-contraction coupling and degradation of membrane α-fodrin via activation of calpain.

Transplantation of dopamine-secreting cells harvested from fetal mesencephalon directly into the striatum has had limited success as a therapy for Parkinson's disease. A major problem is that the majority of the cells die during the first 3 weeks following transplantation. Hypoxia in the tissue surrounding the graft is a potential cause of the cell death. We have used subtractive cDNA libraries and microarray analysis to identify the gene expression profile that regulates tolerance to hypoxia. An improved understanding of the molecular basis of hypoxia-tolerance may allow investigators to engineer cells that can survive in the hypoxic environment of the brain parenchyma following transplantation.

Acute exposure to hypoxia causes a release of adenosine (ADO) that is inversely related to the O2 levels in oxygen-sensitive pheochromocytoma (PC12) cells. In the current study, chronic exposure (48 h) of PC12 cells to moderate hypoxia (5% O2) significantly enhanced the release of ADO during severe, acute hypoxia (1% O2). Investigation into the intra- and extracellular mechanisms underpinning the secretion of ADO in PC12 cells chronically exposed to hypoxia revealed changes in gene expression and activities of several key enzymes associated with ADO production and metabolism, as well as the down-regulation of a nucleoside transporter. Decreases in the enzymatic activities of ADO kinase and ADO deaminase accompanied by an increase in those of cytoplasmic and ecto-5′-nucleotidases bring about an increased capacity to produce intra- and extracellular ADO. This increased potential to generate ADO and decreased capacity to metabolize ADO indicate that PC12 cells shift toward an ADO producer phenotype during hypoxia. The reduced function of the rat equilibrative nucleoside transporter rENT1 also plays a role in controlling extracellular ADO levels. The hypoxia-induced alterations in the ADO metabolic enzymes and the rENT1 transporter seem to increase the extracellular concentration of ADO. The biological significance of this regulation is unclear but is likely to be associated with modulating cellular activity during hypoxia.

The cellular response to hypoxia is complex. Specialized oxygen chemosensitive cells that are excitable respond to reduced O2 by membrane depolarization, altered gene expression, and neurotransmitter secretion. We have used the O2-sensitive pheochromocytoma (PC12) cell line to investigate the cellular response to hypoxia. Here, we present evidence that membrane depolarization and increased intracellular free Ca2+ are major regulatory events in these cells. Membrane depolarization is mediated by the inhibition of a slow-inactivating voltage-dependent potassium (K) channel. Evidence from molecular biology and patch-clamp studies indicate that the O2-sensitive K channel is a member of the Kv1 family. We also reviewed findings on the regulation of gene expression in PC12 cells during hypoxia. An increase in intracellular free Ca2+ is required for hypoxia-induced transcription of a number of genes including tyrosine hydroxylase (TH), the rate-limiting enzyme in the synthesis of catecholamine neurotransmitters, and several of the immediate early genes. We also reviewed the role of dopamine (DA) and adenosine (ADO) receptors in regulation of membrane depolarization and gene expression.

Regional metabolic alterations induced by systemic administration of kainic acid were investigated in rat brains. The histochemical study revealed that an acidic pH shift preceded an ATP decrease in the limbic structures. In the hippocampal Ammon's horn, it was noted that a selective decrease of ATP occured in the dendritic subfield, such as the stratum radiatum and/or the stratum oriens. It was suggested that this selective ATP decrease in the dendrite is directly related to kainate neurotoxicity.

1 Adenosine has been shown to decrease Ca2+ current (ICa) and attenuate the hypoxia-induced enhancement of intracellular free Ca2+ ([Ca2+]i) in oxygen-sensitive rat phaeochromocytoma (PC12) cells. These effects are mediated via the adenosine A2A receptor and protein kinase A (PKA). The current study was undertaken to determine the effects of adenosine on Ca2+ current and hypoxia-induced change in [Ca2+]i during chronic hypoxia. 2 Whole cell patch-clamp studies revealed that the effect of adenosine on ICa was significantly reduced when PC12 cells were exposed to hypoxia (10 % O2) for 24 and 48 h. 3 Ca2+ imaging studies using fura-2 revealed that the anoxia-induced increase in [Ca2+]i was significantly enhanced when PC12 cells were exposed to 10 % O2 for up to 48 h. In contrast, the inhibitory effects of adenosine on anoxia-induced elevation of [Ca2+]i was significantly blunted in PC12 cells exposed to hypoxia for 48 h. 4 Northern blot analysis revealed that mRNA for the A2A receptor, which is the only adenosine receptor subtype expressed in PC12 cells, was significantly upregulated by hypoxia. Radioligand binding analysis with [3H]CGS21680, a selective A2A receptor ligand, showed that the number of adenosine A2A receptor binding sites was similarly increased during exposure to 10 % O2 for 48 h. 5 PKA enzyme activity was significantly inhibited when PC12 cells were exposed to 10 % O2 for 24 and 48 h. However, we found that hypoxia failed to induce change in adenosine- and forskolin-stimulated adenylate cyclase enzyme activity. Chronic hypoxia also did not alter the immunoreactivity level of the G protein Gsα, an effector of the A2 signalling pathway. 6 Whole cell patch-clamp analysis showed that the effect of 8-bromo-cAMP, an activator of PKA, on ICa was significantly attenuated during 48 h exposure to 10 % O2. 7 We conclude therefore that the reduced effect of adenosine on ICa and [Ca2+]i in PC12 cells exposed to chronic hypoxia is due to hypoxia-induced downregulation of PKA. This mechanism may serve to reduce the negative feedback on ICa and [Ca2+]i by adenosine and therefore maintain enhanced membrane excitability of PC12 cells during long-term hypoxia.

This study sought to determine the effects of grafting the internal thoracic artery (ITA) to the left anterior descending coronary artery (LAD) on long-term (10-year) survival, the cardiac death-free rate, and on the cardiac event-free rate in Japanese patients.The use of ITA grafts has been reported to enhance postoperative survival and to decrease the occurrence of cardiac events in the Western literature. However, the survival benefits in Japanese patients, who may have different prognoses with coronary artery disease and a different fate of a saphenous vein graft, have not yet been determined.A total of 954 consecutive patients who underwent coronary artery bypass graft operations (CABG) during the last 12 years at the Nara Medical University were followed and evaluated. Of these, 713 patients underwent ITA-CABG to at least the LAD (ITA group), and 241 patients received a saphenous vein graft (SVG) to the LAD (SVG group). At the time of operation, no significant difference was found between these two groups in age, sex ratio left ventricular ejection fraction, left ventricular end-diastolic pressure, cardiac index, incidence of unstable angina, or in the necessity for an emergency operation. However, those patients who received ITA-CABG had significantly higher incidences of diabetes mellitus, hyperlipidemia, and left main coronary artery disease.The 10-year cumulative graft patency rate for the LAD was 23% higher in the ITA group (90.3%) compared to the SVG group (67.0%), (p.0001). Despite increased preoperative risk factors, patients in the ITA group showed significant improvements in their 5- and 10-year cumulative survival rates as well as in their cardiac death-free and event-free rates. Furthermore, this study demonstrated that ITA grafts improved the prognoses of patients with diabetes mellitus or left ventricular dysfunction and lowered both the long-term postoperative cardiac-death rate and the cardiac-event rate.The use of ITA grafts was effective in improving both the postoperative survival and cardiac event-free rates, and should be recommended in patients with diabetes mellitus or left ventricular dysfunction. ITA grafting to the LAD should be a routine operation in almost all categories of such patients.

We examined effects of selective M1 antagonists on hypercapnic and hypoxic ventilatory responses in 17 healthy human volunteers. Subjects were intravenously treated with placebo, pirenzepine (10 mg) and biperiden lactate (4 mg) on three separate days in a randomized double-blind design. Ventilatory responses to hyperoxic progressive hypercapnia and isocapnic progressive hypoxia were studied after the drug administration. There were no statistically significant differences in the mean delta VE/delta PET CO2 or delta VE/delta SaO2 among the three treatments. However, the delta VE/delta PET CO2 with placebo negatively correlated with the difference in delta VE/delta PET CO2 between the biperiden and placebo studies (r=-0.65, P < 0.01), but not with that between the pirenzepine and placebo studies. On the other hand, the delta VE/delta SaO2 with placebo negatively correlated with the difference in delta VE/delta SaO2 between the pirenzepine and placebo studies (r = -0.79, P < 0.001), but not with that between the biperiden and placebo studies. These data suggest the possible involvement of M1 cholinergic receptors in the central CO2 and peripheral O2 sensing mechanisms in humans, although the degree of its involvement is not consistent among subjects. These findings may explain the interindividual variation in the control of breathing in humans.

Oxygen is the final acceptor of electrons in the synthesis of ATP by the mitochondrial respiratory chain and is therefore an obligatory substrate for energy transformation in most biological systems. A reduction in O2 tension severely limits the ability of cells to perform energy-dependent functions and, if the hypoxia is severe enough, it can be life threatening. It is therefore not surprising that an elaborate control system has evolved in most species for optimizing the delivery of O2 to cells. In mammals, an essential component of this system is the carotid body; a small organ that is located bilaterally at the bifurcation of the carotid artery. The carotid body contains O2-sensitive (type I) cells that are stimulated by reduced O2 tension. The type I cells transmit information concerning the O2 status of arterial blood to closely situated primary sensory afferent fibers by release of neurotransmitter. A major problem confronting contemporary biology is identification of the molecular and cellular mechanisms that couple environmental stimuli with changes in cell phenotype and function. However, after several decades of intense investigations, the mechanisms by which type I cells detect changes in O2 tension and transduce this signal into an increase in neurotransmitter synthesis and release remain unknown.

Neonatal rats, 7 days of age, underwent unilateral carotid artery ligation followed by exposure to hypoxia (8% O2) for 80 min. At the end of the period of hypoxia, and after recovery for 2 or 24 h, regional levels of ATP and heat-shock protein-72 (hsp72) mRNA were measured in adjacent brain sections using ATP-luminescence histochemistry and in situ hybridization, respectively. At the end of hypoxia, ATP levels were decreased in a patchy pattern within the hemisphere ipsilateral to the carotid ligation. In the parietal cortex, the reduction of ATP often occurred in columns oriented perpendicular to the cortical surface. Expression of hsp72 mRNA was not detected prior to recovery, except in the ventricular lining of the ipsilateral hemisphere. However, by 2 h of recovery, hsp72 mRNA was expressed in a diffuse pattern in the ipsilateral hemisphere, even in regions in which the distribution of ATP remained patchy. Although the regional extent of expression varied in different animals, hsp72 mRNA was expressed consistently in the subcortical white matter, which, in some animals, was the only region showing expression. In contrast to the diffuse pattern of expression at 2 h of recovery, expression of hsp72 mRNA at 24 h was highly localized in the superficial layers of cerebral cortex and the pyramidal cell layer of hippocampus. The present results demonstrate that hypoxia–ischemia causes regionally distinct alterations in ATP and hsp72 mRNA that may be related to cell injury in this model.

We examined the long-term effects of octreotide, a somatostatin analogue, on ventilation in a case of cirrhotic hypoxemia. After daily administration of octreotide for one month, the dyspnea on exertion was notably ameliorated, although pulmonary gas exchange was only slightly improved. The octreotide therapy reduced the hypoxic ventilatory drive, which may be one reason for the relief of the dyspnea sensation.

A 56-year-old man was admitted for the evaluation of recurrent pulmonary infections. Since the patient presented with the combination of diffuse cystic bronchiectasis, chronic sinusitis and obstructive azoospermia, the diagnosis of Young's syndrome was made. Because the sweat chloride value, pancreatic function and ciliary ultrastructure were normal, this case could be clearly differentiated from cystic fibrosis and primary ciliary dyskinesia. There have been only a few reported cases of Young's syndrome in Japan.

The purpose of this study is to examine the relationship between mechanical factors and the load compensation during hypercapnia in emphysema. In 36 clinically stable patients, we conducted pulmonary function tests and hypercapnic ventilatory response (HCVR) tests with and without inspiratory flow-resistive loading (IRL) (17 cm H2O/L/s). The mean value of HCVR significantly decreased with IRL, while that of the mouth occlusion pressure (P0.1) response increased. Regardless of IRL, the HCVR values were correlated with FEV1/FVC and airway resistance. The load compensation, evaluated by the ratio of the HCVR value and the P0.1 response before and after IRL, was inversely correlated with percent FRC (r = -0.38, r = -0.39; both p0.05). Breathing pattern analysis at the end-tidal pressure of carbon dioxide of 55 mm Hg elicited the decrease of (tidal volume/inspiratory time (VT/TI) and the increase of TI and TI/TTOT. Although the absolute changes of VT and f were inconsistent among subjects, each relative ratio before and after IRL was correlated again with percent FRC (r = -0.46, r = 0.44: both p0.01). Therefore, the position of the inspiratory muscles at the onset of inspiration may influence the load compensation during hypercapnia in emphysema.

Theophylline, a methylxanthine, is known to stimulate ventilation and augment the ventilatory response to hypoxia in humans by several proposed mechanisms.1, 2 Since theophylline, an adenosine receptor antagonist, has been shown to substantially reduce cerebral blood flow (CBF) in humans,3, 4 as well as in some animal species,5 these effects may have some relevance to the ventilation-stimulating effect of theophylline. If the acid-base status in the brain is altered as a consequence of changes in CBF, it would affect the activity of the central chemosensitivity and thus the level of ventilation. Since some animal studies have shown that effects of theophylline on CBF are apparent during hypoxia but not during normoxia,6, 7 the effect of theophylline on the PCO2 and acid-base status in the brain may be changeable during normoxia and hypoxia. One approach by which we can approximately estimate what is occurring in the brain in humans is to measure partial gas pressures and pH in the internal jugular vein. With a technique for sampling blood from the internal jugular vein, we have previously shown that PCO2 in the internal jugular vein significantly decreases, by 2 to 3 mmHg, under isocapnic hypoxia,8, 9 which probably reflects hypoxia-induced cerebral vasodilation. The aims of this study are first to evaluate the effect of theophylline on PCO2 and pH in the internal jugular vein for a wide range of arterial PO2 (PaO2) under isocapnic conditions and second to examine the possibility that the augmented ventilatory response to hypoxia caused by theophylline is due to attenuation of hypoxia-induced cerebral vasodilation.

Compensatory mechanisms in response to respiratory mechanical loading involve various steps in the control of breathing.1 These include changes in the intrinsic properties of the respiratory muscles, reflexes from mechanoreceptors in the thorax, lungs and airways, and the chemoreceptor reflexes. In addition, conscious appreciation of the load in the higher brains is implicated as a behavioral component of respiratory compensation to loading. Tack and coworkers reported, using the magnitude-estimation method, that the respiratory sensation of resistive loads as well as elastic ones is diminished in elderly healthy subjects.2, 3 However, effects of aging on the load compensation reflex and the sensation of dyspnea have not been simultaneously studied. To examine this, we studied, in healthy volunteers, the ventilatory and occlusion pressure responses to progressive hypercapnia with and without inspiratory flow-resistive loading while the intensity of dyspnea was simultaneously assessed by visual analogue scaling.

A simple method was developed to measure in vivo local oxygen consumption quantitatively in the brain cortex. Reflectance spectra of tissue hemoglobin at the brain's surface were measured for assessment of both local tissue hemoglobin content and its oxygen saturation. Local oxygen consumption was calculated from the spectral changes of tissue hemoglobin during complete cessation of blood flow by compression of the cortical surface in the suprasylvian gyrus with the tip of an optic probe. This procedure was performed without any brain damage and only took ∼5 s. The calculated local oxygen consumption during this short period of compression remained constant for a few seconds. Then, it decreased rapidly, although the local tissue hemoglobin was not completely deoxygenated. The value of local cerebral oxygen consumption obtained by this method was 3.02 ± 0.61 mL O2/100 g brain/min; it was not influenced by the change in systemic blood pressure. The effect of pentobarbital on cerebral oxygen consumption was also studied. At the stage of burst and suppression on electrocorticogram, cerebral oxygen consumption decreased significantly (p < 0.001) to 1.03 ± 0.07 mL O2/100 g brain/min.