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A technique for achieving the in-cylinder stratification of external exhaust gas recirculation (EGR) gas in direct-injection (DI) diesel engines has been developed to reduce toxic exhaust emissions. The external EGR gas is supplied from one of the two intake ports which can create a swirl flow in either the upper or lower portion of the cylinder during the intake stroke. In the final stage of the compression stroke, a squish flow conveys the vertically stratified EGR gas into the piston cavity, generating a radially stratified EGR gas in the piston cavity at the end of the compression stroke. This strategy for achieving EGR gas stratification in the piston cavity was developed by using an unsteady computational fluid dynamics (CFD) code. Prior to the exhaust emission tests, the accuracy of the simulation was evaluated by planer laser-induced fluorescence (LIF) imaging. The exhaust emission tests showed that there was less smoke emission under medium load conditions when the EGR gas was delivered to the inner part of the piston cavity. The mechanism of this smoke reduction was investigated using CFD simulation, which is based on a series of calculations related to the internal flow of the injector nozzle, the in-cylinder fuel spray, and mixture formation and combustion. It has been shown that, at the beginning of the combustion, the higher concentration of EGR gas in the inner part of the cavity lowers the combustion temperature and reduces the soot formation rate. Air, which exists in the outer part of the cavity at the start of fuel injection, enhances the oxidation of the soot cloud in the piston cavity periphery in the latter half of the combustion period. [ABSTRACT FROM AUTHOR]

In this paper, we propose a photodegradation correction method for the dual-luminophore pressure-sensitive paint (PSP) measurement using lifetime-based imaging, which was proposed for correction of the temperature-induced error but has suffered from photodegradation in the previous studies. We introduced a parameter that characterizes the photodegradation of a dual-luminophore PSP as the intensity ratio between the two luminophores. The changes in the calibration coefficients for the pressure and the temperature due to photodegradation were corrected based on this parameter. In this study, a coupon-based calibration test was performed, and the luminescence characteristics of the dual-luminophore PSP including photodegradation were investigated. Then, the proposed method was applied to a coupon-based validation test and a jet impingement test, and the effectiveness of the method was evaluated by comparing results with and without correction. The pressure measurement accuracy was significantly improved by photodegradation correction., (© 2024 Author(s). Published under an exclusive license by AIP Publishing.)

Cu 2 O/CuO bilayers were fabricated by electrodeposition of the CuO layer in a copper(II)-ammonia complex aqueous solution, followed by photoelectrochemical deposition of the Cu 2 O layer at potentials ranging from -0.3 to -1.0 V referenced to a Ag/AgCl electrode in a copper(II)-lactate complex aqueous solution under light irradiation, and the effects of varied potentials of the photoelectrochemical Cu 2 O depositions and post-heating conditions on their structural, optical, and photovoltaic characteristics were investigated with X-ray diffraction, field emission-scanning electron microscopy, optical absorption measurements, and external quantum efficiency (EQE) measurements with and without applied bias voltage. The Cu 2 O layers with a characteristic 2.1 eV band gap energy were adhesively stacked on the thorn-like grains of the CuO layers possessing a characteristic 1.5 eV band gap energy, and dense and defect-free Cu 2 O/CuO bilayers could be fabricated at the potentials of -0.4 and -0.5 V, but the grain size of Cu 2 O decreased at -0.5 V. In addition, the metallic Cu was deposited simultaneously at potentials less than -0.7 V. The Cu 2 O/CuO bilayer fabricated at -0.4 V revealed photovoltaic features at wavelengths ranging from 350 nm to approximately 900 nm, and a maximum EQE value of 56.8% was achieved at 510 nm in wavelength with a bias voltage of -0.1 V. The maximum EQE value, however, decreased to 1.2% accompanied with the peak wavelength shift to 580 nm, and no photovoltaic feature was observed at potentials of -0.3, -0.7, and -1.0 V. The photovoltaic performance for the Cu 2 O/CuO bilayer fabricated at -0.4 V was ameliorated by heating at 423 K, and the maximum EQE values were enhanced to 87.7% at 550 nm and 89.8% at 530 nm in an ambient atmosphere and vacuum. Both the Cu 2 O and CuO layers acted as photovoltaic layers in the Cu 2 O/CuO bilayer fabricated at -0.4 V and heated at 423 K, and the electrical characteristic including the carrier mobility affected the photovoltaic performance. The photovoltaic feature, however, disappeared by heating above 523 K due to the formation of nanopores inside the CuO layer and near the CuO heterointerface to the Cu 2 O and fluorine-doped tin oxide substrate., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

Factors that cause nonuniformity in the luminescence lifetime of pressure-sensitive paints (PSPs) were investigated. The lifetime imaging method of PSP does not theoretically require wind-off reference images. Therefore, it can improve measurement accuracy because it can eliminate errors caused by the deformation or movement of the model during the measurement. However, it is reported that the luminescence lifetime of PSP is not uniform on the model, even under uniform conditions of pressure and temperature. Therefore, reference images are used to compensate for the nonuniformity of the luminescence lifetime, which significantly diminishes the advantages of the lifetime imaging method. In particular, fast-responding PSPs show considerable variation in luminescence lifetime compared to conventional polymer-based PSPs. Therefore, this study investigated and discussed the factors causing the nonuniformity of the luminescence lifetime, such as the luminophore solvent, luminophore concentrations, binder thickness, and spraying conditions. The results obtained suggest that the nonuniformity of the luminophore distribution in the binder caused by the various factors mentioned above during the coating process is closely related to the nonuniformity of the luminescence lifetime. For example, when the thickness of the binder became thinner than 8 μm, the fast-responding PSPs showed a tendency to vary significantly in the luminescence lifetime. In addition, it was found that the luminescence lifetime of fast-responding PSP could be changed in the depth direction of the binder depending on the coating conditions. Therefore, it is important to distribute the luminophore uniformly in the binder layer to create PSPs with a more uniform luminescence lifetime distribution.

Polymer/ceramic pressure-sensitive paint (PC-PSP), which incorporates a high percentage of particles in the binder layer, is proposed in order to improve the characteristics of PSP. The procedure for embedding particles into the binder layer was modified. In the conventional procedure, dye is adsorbed onto a polymer/ceramic coating film (denoted herein as a dye-adsorbed (D-adsorbed) PSP). In the new procedure, the mixture of a dye and particles is adsorbed onto a polymer coating film (denoted herein as the particle/dye-adsorbed (PD-adsorbed) PSP). The effect of particle mass content on PSP characteristics was investigated. In addition, the effect of solvent on PSP characteristics and film structure were evaluated for the PD-adsorbed PSP. As a result, the difference in the PSP characteristics between the two types of PSP was clarified. Although surface roughness and time response increase with increased mass content of particles for both D- and PD-adsorbed PSPs, the critical pigment volume concentration (CPVC) for the PD-adsorbed PSP is smaller than that of the D-adsorbed PSP (88 wt% and 93 wt%, respectively). The PD-adsorbed PSP has a higher frequency response comparing with the D-adsorbed PSP while maintaining the same surface roughness. Observation by scanning electron microscope showed that the CPVC of the PC-PSP is governed primarily by surface structure. The coating film structure can be roughly classified into two states depending on the particle mass content. One is a state in which the coating film consisted of two layers: a lower particle-rich layer and an upper polymer-rich layer. This type of structure was observed in the PD-adsorbed PSP as well as in the D-adsorbed PSP. In the other state, polymer and particles are homogeneously distributed in the film, and pores are formed. This difference in the coating structure results in a change in the time response.

Two patients developed de novo vertebral artery dissecting aneurysm after contralateral vertebral artery occlusion. A 36-year-old man presented with brainstem ischemia and was treated non-surgically. Subsequent angiography showed spontaneous vertebral artery occlusion at the site of dissection. A 45-year-old man developed subarachnoid hemorrhage due to vertebral artery dissecting aneurysm. He underwent endovascular occlusion of the vertebral artery proximal to the dissecting aneurysm. These patients developed de novo dissecting aneurysm on the contralateral vertebral artery at 13 months and 11 days after unilateral vertebral artery occlusion, respectively. These cases strongly suggest that changes in hemodynamic stress due to unilateral vertebral artery occlusion are related to de novo dissecting aneurysm on the contralateral side. The risk of de novo dissecting aneurysm may be increased by proximal occlusion or trapping of dissecting aneurysm of the contralateral vertebral artery.

A 57-year-old male presented with a frontal bone defect associated with a middle meningeal arteriovenous fistula (AVF) manifesting as headache. The patient had a history of head injury 19 years previously. Skull radiography and computed tomography demonstrated a left frontal bone defect. Left external carotid angiography demonstrated a middle meningeal AVF at the frontal region, at the same location as the bone defect. The AVF was fed by the bilateral middle meningeal and left deep temporal arteries, and drained by the superior sagittal and ipsilateral cavernous sinuses. The minor feeding artery, the left deep temporal artery, was embolized with polyvinyl alcohol particles, then 0.4 ml of a 1:3 mixture of n-butyl cyanoacrylate and lipiodol was injected from the left middle meningeal artery. Follow-up angiography 3 months after the embolization revealed complete obliteration of the fistula. The bone defect may have been caused by erosion of the frontal bone by the pulsating effect of the feeding and draining vessels of the fistula, or by inadequate nutrition to the bone tissue because of the arteriovenous shunt.

A 66-year-old right-handed man with acquired stuttering was reported. He complained of paresis in his left leg and speech dysfluency. He was not aphasic in terms of comprehension and writing. His speech dysfluency was mainly characterized by initial syllable repetitions. He has apraxia with his left hand, but has neither agraphia with his left hand nor crossed optic ataxia. MRI showed cerebral infarction in the truncus of the corpus callosum, and angiography revealed occlusion of the right anterior cerebral artery. 99mTc HM-PAO SPECT showed decreased blood flow in the right frontal lobe. Within six months of its onset, the patient's speech dysfluency had diminished. As the causative lesion for acquired stuttering, we proposed a hemispheric lesion in addition to a callosal lesion.

Seven patients with internal carotid artery (ICA) stenosis with higher cortical dysfunction due to hemodynamic ischemia were treated by percutaneous transluminal angioplasty (PTA). The patients ranged from 49 to 71 years of age, and included five males and two females. Neuropsychological tests were evaluated before and after PTA. Higher cortical dysfunction improved in all cases after PTA. It is concluded that PTA is effective to improve higher cortical dysfunction in patients who have ICA stenosis associated with hemodynamic compromise, if the ICA is satisfactorily dilated.

Stereotactic thalamotomy was performed in ten patients with Parkinson's disease for the suppression of their tremor. After VL-thalamotomy, contralateral tremor and rigidity disappeared or was significantly reduced. Activities of daily living (ADL) measured by functional independence measure and Parkinson's disability score were improved postoperatively in all patients. There was significant improvement in anxiety index. However, other neuropsychological tests showed no significant change postoperatively. ADL improved after thalamotomy. It is concluded that stereotactic VL-thalamotomy is a useful treatment which improves ADL without cognitive dysfunction.

A case of nontraumatic acute subdural hematoma caused by the rupture of transdural anastomotic vessels in a patient with Moyamoya disease is reported. The patient was a 55-year-old woman who was admitted to our hospital in a comatose state. A diagnosis of acute subdural hematoma associated with Moyamoya disease was made on the basis of CT and angiographic findings. No lesions suggestive of trauma, such as cerebral contusion, could be detected during surgery. Although total evacuation of the hematoma was performed, she developed the apallic syndrome and did not recover consciousness. Judging from the angiographic and operative findings, it appears that subarachnoid hemorrhage occurred first and stretched the transdural anastomotic vessels which supplied the collateral circulation. This led to tearing of some of the vessels, and their proximal ends were consequently exposed in the subdural space. The surgical treatment of acute subdural hematoma associated with Moyamoya disease requires the closest attention to avoid damage to the collateral circulation. Although we carefully arrested the bleeding without using a coagulator in order to spare the collateral vessels, the transdural anastomosis was no longer visible on postoperative angiograms. Our experience suggests that hematoma irrigation with trephination therapy, which may minimize the damage to the collateral circulation, may be the most appropriate treatment for acute subdural hematoma associated with Moyamoya disease. Furthermore, cerebral revascularization should be performed for the treatment of the circulatory disturbance intercepted by the hematoma itself or by operative manipulation.

The distribution of peptidergic nerve fibers containing substance P (SP), calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP), and neuropeptide Y (NPY) in the cerebral arteries and veins of the guinea pig was studied using immunohistochemical techniques. The ultrastructure of these immunoreactive nerve terminals was also compared. The cerebral arteries were innervated by abundant peptidergic nerve fibers with characteristic running patterns, i.e., SP fibers in a meshwork, VIP and NPY fibers in a spiral fashion. Only CGRP fibers showed both meshwork and spiral patterns. In the cerebral veins, the abundant SP fibers innervated the cortical veins, deep cerebral veins, and dural sinuses. However, CGRP, VIP, and NPY fibers in extremely low density were noted merely in the cortical veins. Electron microscopic observations demonstrated that SP-immunoreactive nerve terminals existed apart from the arterial smooth muscle cells, while VIP- and NPY-immunoreactive nerve terminals adjoined them. As for CGRP nerve terminals, some existed close to the arterial smooth muscle cells, and others were found some distance from them. These morphological characteristics observed by light and electron microscopy suggest that SP fibers are not related directly to the vasomotor function, but VIP and NPY fibers are, and that CGRP fibers have a more complicated function. The distribution patterns of the peptidergic nerve fibers are consistent with the suggestion that vasomotor peptidergic fibers may function actively on cerebral arteries and passively on cerebral veins and that SP fibers regarded as sensory fibers may provide information regarding cerebral vascular conditions, innervating every part of both cerebral arteries and veins.

A case of eclampsia with interesting angiographic findings is reported. A 19-year-old woman in the 35th week of gestation by date was admitted due to a sudden onset of generalized clonic convulsion and disturbance of consciousness. The diagnosis was eclampsia. On the second hospital day, extraction of a stillborn female was performed by laminaria. Thereafter, the consciousness improved rapidly and she became alert on the following day. She was discharged without neurological deficit on the 18th hospital day. A CT scan on the day of admission showed narrow lateral ventricles and symmetrical low-density lesions in and around the basal ganglia. These had almost disappeared by the 10th hospital day. Carotid angiography on admission revealed no abnormality in the arterial phase including the lenticulostriate arteries, but, early appearance of deep cerebral veins and some cortical veins was noted. These deep veins, however, were not distinct even in the venous phase. These angiographic findings suggested medullary dilatation caused by circulatory disturbance of the deep cerebral veins. Most authors have stressed the contribution of diffuse arterial vasospasm in the pathogenesis of eclampsia in relation to low-density lesions on CT scans. In the present case, we could not find vasospasm but found circulatory disturbance of the deep cerebral veins. These angiographic findings suggested that the appearance of the low-density lesions on the CT scan was most likely due to venous congestion caused by circulatory disturbance of the deep cerebral veins, since most of the deep medullary veins in the low-density lesions flowed into the deep cerebral veins.(ABSTRACT TRUNCATED AT 250 WORDS)

The distribution of nerve fibers in the cerebral veins was studied by catecholamine fluorescence simultaneously with acetylcholinesterase (AChE) histochemistry. A comparison of nerve fibers in the cerebral arteries was made. The ultrastructure of terminal boutons in the veins fixed with potassium permanganate was also studied. In the adventitia of the cerebral artery, green fluorescent aminergic fibers and brownish AChE-reactive (probably cholinergic) fibers were observed. In contrast, the cerebral venous system showed no AChE-positive fibers. Catecholamine fluorescent varicose fibers were detected in the dural sinus, the internal cerebral vein, and the superficial vein of Labbé. The highest density of aminergic fibers was found in the dural sinus and the second highest in the internal cerebral vein. Most of the terminal boutons in the adventitia of the cerebral veins were found adjacent to a muscle-like cell and showed only cored vesicles under electron microscopy. Results of our study suggest that the cerebral venous system has a neurogenic innervation, mainly from aminergic fibers, which is different from the neurogenic supply to the cerebral arterial system.

The first morphological evidence of the existence of adrenergic receptors (alpha 1, alpha 2 and beta) within the vascular walls of the central nervous system were presented using the in vitro receptor autoradiographic technique. In the rat pial arteries all three types of adrenergic receptors were demonstrated, whereas the human pial arteries failed to show significant autoradiographic grains of alpha 1 type of adrenergic receptors indicating a considerable inter-species difference in the distribution of adrenergic receptors. alpha 2 and beta receptors in human pial arteries were found not only in the arterial smooth muscle layers but also in the endothelial layers. This suggests a possibility that circulating sympathomimetic agents play some role in controlling the tone or permeability of vascular walls within the central nervous system. A distinct distribution of alpha 1 receptors in cortical layer IV where the vascular plexus was richest may suggest a relation of alpha 1 receptors and blood flow of brain parenchyma.

The role of the central 5-hydroxytryptamine (5-HT) neuron system in cerebral microcirculation of the rat was examined by immunohistochemical and hydrogen clearance methods. Immunohistochemical studies demonstrated 5-HT-immunoreactive nerve fibers along intraparenchymal blood vessels (arterioles, capillaries, and venules). Ultrastructural observation revealed that 5-HT-immunoreactive terminal boutons (0.3 to 1.0 micron in diameter) made contact with the basement membrane of the capillaries. After an intracerebral injection of 5,7-dihydroxytryptamine (5,7-DHT), a neurotoxin to the 5-HT neuron system, no 5-HT-immunoreactive nerve fibers were found around the injection site with immunohistochemical techniques. With the hydrogen clearance method, the 5,7-DHT-injected cortex showed no significant change in regional cerebral blood flow (rCBF) in the presence of normocapnia, but a significant increase in rCBF with hypercapnia, compared with the untreated cortex. These facts strongly suggest that the central 5-HT neuron system has an important role in carbon dioxide reactivity of the cerebral blood vessels.

Vasoactive intestinal polypeptide (VIP)- and substance P-containing nerve fibers were observed in the cerebral blood vessels using an immunohistochemical technique. VIP-containing nerve fibers distributed in a spiral pattern, similar to that of muscle cells. Under electron microscopic observation, VIP-immunoreactive terminals lay close to a muscle cell in the inner layer of the adventitia. In contrast, substance P-containing nerve fibers showed a meshwork pattern in the outer layer of the adventitia. Using both acetylcholinesterase (AChE) staining and VIP immunohistochemistry, AChE-positive and VIP-immunoreactive nerve fibers revealed almost the same distribution in the same specimen. The present data suggest that VIP-containing nerve fibers may play a role in the smooth muscle control of the blood vessels, whereas substance P-containing nerve fibers may not take part in muscle control.

Regional cerebral blood flow (CBF) in eight patients in a persistent vegetative state was measured and compared with that in five healthy volunteers. The patients were classified into three groups: Group 1 (locked-in syndrome) consisted of a single patient, Group 2 (typical vegetative state) of five patients, and Group 3 (prolonged coma) of two patients. CBF was measured early after onset by single photon emission computed tomography with 123I-N-isopropyl-p-iodo-amphetamine and/or 99mTc-hexamethyl-propyleneamine oxime. The regions of interest (ROIs) were the bilateral frontal, temporal, parietal, occipital, and cerebellar areas and basal ganglia. The values obtained in these areas were averaged, and the ratio for each ROI [(the value in the ROI/the mean value) x 100] was calculated. "Hyperfrontal distribution" of CBF was found to be rare in both the normal condition and the vegetative state. Higher CBF values were noted in the left than in the right frontal area in four of the five volunteers but in only four of the eight patients. CBF distribution in the frontal lobe was characteristic for each group: Group 1 showed high CBF bilaterally, although the elevation was statistically significant only on the right side, and Group 3 exhibited significantly low values. In Group 2, CBF was variable but, for the most part, within normal limits. Awareness was closely correlated with frontal lobe function and alteration of CBF in the frontal region.

The distribution of nerve fibers in the cerebral blood vessels was studied by a catecholamine histofluorescence method, acetylcholinesterase (AChE) staining and immunohistochemistry. The ultrastructure of the terminal boutons in the vessel wall was also studied. In the adventitia of the cerebral artery, green fluorescence aminergic fibers and brownish AChE-positive (probably cholinergic) fibers were observed. In contrast, the cerebral venous system showed no AChE-positive fibers. The highest density of aminergic fibers were found in the dural sinus and the second highest in the internal cerebral vein. Serotonin immunoreactive nerve fibers were found along small intraparenchymal blood vessels such as perforating arteries in the brain stem, and arterioles and venules in the cerebral cortex. Under ultrastructural observation, a serotonin immunoreactive terminal was demonstrated in conjunction with the basement membrane of the capillary.

The role of intracortical vasoactive intestinal polypeptide (VIP)-containing neurons in the regulation of cortical blood flow was investigated in rats by immunohistochemical and hydrogen clearance methods. Immunohistochemical studies revealed an intimate association between intracortical VIP-containing neurons and small blood vessels. Intracortical injection of a VIP solution (10(-5) M) produced significantly higher blood flow in the treated cortex (mean +/- standard error of the mean: 46.2 +/- 4.0 ml/100 gm/min) than in the untreated cortex (36.9 +/- 2.4 ml/100 gm/min). These data suggest that intracortical VIP-containing neurons produce dilatation of intracortical blood vessels.

The density and distribution pattern of aminergic nerve fibers in intracranial and extracranial veins were compared by means of catecholamine histofluorescence studies. Extracranial veins (internal jugular, inferior caval, portal, renal, internal iliac, and femoral veins) showed quite a uniform distribution pattern. Large veins (jugular, caval, renal, and iliac veins) revealed a spiral pattern, and small veins presented as a meshwork (femoral vein) or in a longitudinal pattern (a branch of the femoral vein). In contrast, intracranial veins displayed more complex patterns: the dural sinus showed a longitudinal pattern and the internal cerebral vein and the superficial vein of Labbé revealed a meshwork of nerve fibers. The aminergic fibers were denser in cerebral veins (dural sinus and internal cerebral vein) than in extracranial veins. The complex distribution and the density of aminergic fibers in cerebral veins suggest that the aminergic innervation of the circulatory system may be more important in the brain than in the extracranial organs.

The microangioarchitecture of corrosion casts of the cat spinal cord was studied by scanning electron microscopy. On the ventral surface of the spinal cord, the anterior spinal artery and the anterior spinal vein ran parallel along the anterior median fissure. Many central arteries branching from the anterior spinal artery coursed in a wavelike manner in the anterior median fissure. The number of central arteries was lowest in the thoracic spinal cord. Central arteries at some spinal cord levels revealed well-developed anastomoses with other central arteries in the anterior median fissure. These well-developed anastomotic central arteries were frequently observed in the thoracic spinal cord, in which the number of central arteries was lowest. On the dorsal surface of the spinal cord, the posterior spinal vein ran longitudinally at the midline and was drained by circumferential veins and posterior central veins. This vein formed a characteristic anastomotic plexus. Small arterioles (20 microns in diameter) in the spinal parenchyma revealed a ring-like compression at the branching site.

The distribution patterns of aminergic and cholinergic nerve fibers in the feline spinal blood vessels were studied by means of amine histofluorescence and acetylcholinesterase (AChE) staining. The anterior spinal artery had a dense network of aminergic and AChE-positive (probably cholinergic) nerve fibers. The posterior spinal vein, in contrast, had only aminergic nerve fibers. Intraparenchymal small blood vessels in the spinal cord also had strongly fluorescent (probably peripheral) aminergic nerve fibers. This was quite a characteristic feature in the spinal cord. The distribution pattern and the density of these two sorts of nerve fibers widely varied with the individual segment of the spinal cord. The thoracic spinal cord had the lowest number of these nerve fibers throughout the spinal cord. This fact may give a clue to explain why the thoracic spinal cord is most susceptible to ischemic change.

Vasopressin-immunoreactive nerve fibers were demonstrated in the cerebral pial arteries by peroxidase immunohistochemistry. In the large pial artery (proximal part of the middle cerebral artery), they ran longitudinally to the long axis of the vessel. They ran in a spiral pattern in the distal part of the middle cerebral artery. Even in small arteries, vasopressin nerve fibers were found arranged in a longitudinal fashion. The present morphological data suggest that vasopressin nerve fibers in the cerebral artery may play a role in cerebral circulation.

By an immunohistochemical technique, vasoactive polypeptide (VIP)-and substance P-containing nerve fibers are observed in the cerebral blood vessels. VIP-containing nerve fibers distribute in a spiral pattern, similar to the muscle cell distribution pattern. Under an electron microscopic observation, VIP-immunoreactive terminals lie just near to a muscle cell in the inner layer of the adventitia. In contrast, substance P-containing nerve fibers show a meshwork pattern in the outer layer of the adventitia. In combination of acetylcholinesterase (AChE) staining and VIP immunohistochemistry, AChE-positive and VIP-immunoreactive nerve fibers reveal almost same distribution in the same specimen. The present data suggest that VIP-containing nerve fibers may play a role of smooth muscle control of the blood vessels, while substance P-containing nerve fibers may not take part in muscle control.

To supplement catecholamine deficit in the brain with Parkinson disease, we have aimed to transplant the superior cervical ganglion (SCG), which contains norepinephrine and dopamine, into the brain. 1. Transplantation of SCG into rat cerebral cortex SCG was transplanted into the same rat's parietal cortex. Three weeks after the transplantation, catecholamine histofluorescence revealed many transplanted catecholamine cells in the cortex. However, no fibers extended from the transplanted tissue to the cerebral cortex. Some catecholamine fibers extended to the cerebral cortex where 6-OHDA (a specific neurotoxin to the catecholamine neuron) had been pretreated. 2. Transplantation of SCG into the caudate nucleus of MPTP-induced Parkinson monkey For animal model of Parkinson disease, MPTP (1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine) was administered to 5 monkeys. Tow weeks after MPTP administration, dopamine terminals disappeared in the caudate nucleus. After transplantation of SCG in the same animal, many transplanted SCG cells extended their axons to the caudate nucleus. The present results showed that transplanted SCG cells were well survived in the brain. Under a special circumstance such as shortage of catecholamine in the brain, transplanted SCG cells extended their axons into the brain. It is suggested that the transplantation of SCG can be a new therapy for Parkinson disease.

Three dimensional observation of the nerve fibers along the cerebral blood vessels was investigated by scanning electron microscopy. Electron probe X-ray microanalysis was also performed in the cerebral blood vessels treated with peroxidase-antiperoxidase immunohistochemistry intensified by nickel ammonium sulfate. Nerve fibers (2-8 microns in diameter) formed a plexus on the outer surface of the adventitia. After branching, the nerve fibers penetrated the blood vessel adventitia. Substance P-immunoreactive nerve fibers showed a meshwork pattern in the outer layer of the adventitia, and vasoactive intestinal polypeptide (VIP)-immunoreactive nerve fibers revealed a spiral running pattern in the inner layer of the adventitia. Taken together with previous studies, these findings suggest that substance P nerve fibers in the cerebral arteries may not be related to arterial dilatation or constriction, but VIP nerve fibers may be vasodilative.