Metallic radionuclide-labeled tetrameric 2,6-diisopropylphenyl azides for cancer treatment

This study proposes a new method for radionuclide therapy that involves the use of oligomeric 2,6-diisopropylphenyl azides and a chelator to form stable complexes with metallic radionuclides. The technique works by taking advantage of the endogenous acrolein produced by cancer cells. The azides react with the acrolein to give a diazo derivative that immediately attaches to the nearest organelle, effectively anchoring the radionuclide within the tumor. Preliminary in vivo experiments were conducted on a human lung carcinoma xenograft model, demonstrating the feasibility of this approach for cancer treatment.

Tumor Targeting of 211At-Labeled Antibody under Sodium Ascorbate Protection against Radiolysis

Astatine-211 (²¹¹At) is an alpha emitter applicable to radioimmunotherapy (RIT), a cancer treatment that utilizes radioactive antibodies to target tumors. In the preparation of ²¹¹At-labeled monoclonal antibodies (²¹¹At-mAbs), the possibility of radionuclide-induced antibody denaturation (radiolysis) is of concern. Our previous study showed that this ²¹¹At-induced radiochemical reaction disrupts the cellular binding activity of an astatinated mAb, resulting in attenuation of in vivo antitumor effects, whereas sodium ascorbate (SA), a free radical scavenger, prevents antibody denaturation, contributing to the maintenance of binding and antitumor activity. However, the influence of antibody denaturation on the pharmacokinetics of ²¹¹At-mAbs relating to tumor accumulation, blood circulation time, and distribution to normal organs remains unclear. In this study, we use a radioactive anti-human epidermal growth factor receptor 2 (anti-HER2) mAb to demonstrate that an ²¹¹At-induced radiochemical reaction disrupts active targeting via an antigen-antibody interaction, whereas SA helps to maintain targeting. In contrast, there was no difference in blood circulation time as well as distribution to normal organs between the stabilized and denatured immunoconjugates, indicating that antibody denaturation may not affect tumor accumulation via passive targeting based on the enhanced permeability and retention effect. In a high-HER2-expressing xenograft model treated with 1 MBq of ²¹¹At-anti-HER2 mAbs, SA-dependent maintenance of active targeting contributed to a significantly better response. In treatment with 0.5 or 0.2 MBq, the stabilized radioactive mAb significantly reduced tumor growth compared to the denatured immunoconjugate. Additionally, through a comparison between a stabilized ²¹¹At-anti-HER2 mAb and radioactive nontargeted control mAb, we demonstrate that active targeting significantly enhances tumor accumulation of radioactivity and in vivo antitumor effect. In RIT with ²¹¹At, active targeting contributes to efficient tumor accumulation of radioactivity, resulting in a potent antitumor effect. SA-dependent protection that successfully maintains tumor targeting will facilitate the clinical application of alpha-RIT.

Chemical effect on muonic atom formation through muon transfer reaction in benzene and cyclohexane samples

To investigate the chemical effect on the muon capture process through a muon transfer reaction from a muonic hydrogen atom, the formation rate of muonic carbon atoms is measured for benzene and cyclohexane molecules in liquid samples. The muon transfer rate to carbon atoms of the benzene molecule is higher than that to the carbon atoms of the cyclohexane molecule. Such a deviation has never been observed among those molecules for gas samples. This may be because the transfers occur from the excited states of muonic hydrogen atoms in the liquid system, whereas in the gas system, all the transfers occur from the 1s (ground) state of muon hydrogen atoms. The muonic hydrogen atoms in the excited states have a larger radius than those in the 1s state and are therefore considered to be affected by the steric hindrance of the molecular structure. This indicates that the excited states of muonic hydrogen atoms contribute significantly to the chemical effects on the muon transfer reaction.

New neurons use Slit-Robo signaling to migrate through the glial meshwork and approach a lesion for functional regeneration

After brain injury, neural stem cell-derived neuronal precursors (neuroblasts) in the ventricular-subventricular zone migrate toward the lesion. However, the ability of the mammalian brain to regenerate neuronal circuits for functional recovery is quite limited. Here, using a mouse model for ischemic stroke, we show that neuroblast migration is restricted by reactive astrocytes in and around the lesion. To migrate, the neuroblasts use Slit1-Robo2 signaling to disrupt the actin cytoskeleton in reactive astrocytes at the site of contact. Slit1-overexpressing neuroblasts transplanted into the poststroke brain migrated closer to the lesion than did control neuroblasts. These neuroblasts matured into striatal neurons and efficiently regenerated neuronal circuits, resulting in functional recovery in the poststroke mice. These results suggest that the positioning of new neurons will be critical for functional neuronal regeneration in stem/progenitor cell-based therapies for brain injury.

Attenuation by dietary taurine of dextran sulfate sodium-induced colitis in mice and of THP-1-induced damage to intestinal Caco-2 cell monolayers

The effects of dietary taurine on the experimental colitis induced by dextran sulfate sodium (DSS) in mice were evaluated. C57BL/6 female mice were given 3% DSS in drinking water for 5 d to induce acute colitis. Taurine at 2% was added to the drinking water 5 d before and during the DSS-treatment to investigate its preventive effect. Taurine supplementation significantly attenuated the weight decrease, diarrhea severity, colon shortening, and the increase in the colonic tissue myeloperoxidase activity induced by DSS. Taurine also significantly inhibited the increase in the expression of a pro-inflammatory chemokine, macrophage inflammatory protein 2 (MIP-2), but not of interleukin (IL)-1beta or tumor necrosis factor (TNF)-alpha mRNA. Furthermore, taurine significantly protected the intestinal Caco-2 cell monolayers from the damage by macrophage-like THP-1 cells in an in vitro coculture system. These results suggest that taurine prevented DSS-induced colitis partly in association with (1) its inhibitory effects on the secretion of MIP-2 from the intestinal epithelial cells and on the infiltration of such inflammatory cells as neutrophils and (2) its cytoprotective functions on the epithelial barrier from the direct toxicity of DSS and from the inflammatory cell-induced injury.

The role of TNFalpha and IL-17 in the development of excess IL-1 signaling-induced inflammatory diseases in IL-1 receptor antagonist-deficient mice

IL-1 receptor antagonist (IL-1Ra)-deficient mice spontaneously develop several inflammatory diseases, resembling rheumatoid arthritis, aortitis, and psoriasis in humans. As adoptive T cell transplantation could induce arthritis and aortitis in recipient mice, it was suggested that an autoimmune process is involved in the development of diseases. In contrast, as dermatitis developed in scid/scid-IL-IRa-deficient mice and could not be induced by T cell transfer, a T cell-independent mechanism was suggested. The expression of proinflammatory cytokines was augmented at the inflammatory sites. The development of arthritis and aortitis was significantly suppressed by the deficiency of TNFalpha or IL-17. The development of dermatitis was also inhibited by the deficiency of TNFalpha. These observations suggest that TNFalpha and IL-17 play a crucial role in the development of autoimmunity downstream of IL-1 signaling, and excess IL-1 signaling-induced TNFalpha also induces skin inflammation in a T cell-independent manner.

N doping of TiO2(110): Photoemission and density-functional studies

The electronic properties of N-doped rutile TiO2(110) have been investigated using synchrotron-based photoemission and density-functional calculations. The doping via N2+ ion bombardment leads to the implantation of N atoms (approximately 5% saturation concentration) that coexist with O vacancies. Ti 2p core level spectra show the formation of Ti3+ and a second partially reduced Ti species with oxidation states between +4 and +3. The valence region of the TiO(2-x)N(y)(110) systems exhibits a broad peak for Ti3+ near the Fermi level and N-induced features above the O 2p valence band that shift the edge up by approximately 0.5 eV. The magnitude of this shift is consistent with the "redshift" observed in the ultraviolet spectrum of N-doped TiO2. The experimental and theoretical results show the existence of attractive interactions between the dopant and O vacancies. First, the presence of N embedded in the surface layer reduces the formation energy of O vacancies. Second, the existence of O vacancies stabilizes the N impurities with respect to N2(g) formation. When oxygen vacancies and N impurities are together there is an electron transfer from the higher energy 3d band of Ti3+ to the lower energy 2p band of the N(2-) impurities.

Down-regulation of metabotropic glutamate receptor 1alpha in globus pallidus and substantia nigra of parkinsonian monkeys

Enhanced glutamatergic neurotransmission via the subthalamopallidal or subthalamonigral projection seems crucial for developing parkinsonian motor signs. In the present study, the possible changes in the expression of metabotropic glutamate receptors (mGluRs) were examined in the basal ganglia of a primate model for Parkinson's disease. When the patterns of immunohistochemical localization of mGluRs in monkeys administered systemically with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) were analysed in comparison with normal controls, we found that expression of mGluR1alpha, but not of other subtypes, was significantly reduced in the internal and external segments of the globus pallidus and the substantia nigra pars reticulata. To elucidate the functional role of mGluR1 in the control of pallidal neuron activity, extracellular unit recordings combined with intrapallidal microinjections of mGluR1-related agents were then performed in normal and parkinsonian monkeys. In normal awake conditions, the spontaneous firing rates of neurons in the pallidal complex were increased by DHPG, a selective agonist of group I mGluRs, whereas they were decreased by AIDA, a selective antagonist of group I mGluRs, or LY367385, a selective antagonist of mGluR1. These electrophysiological data strongly indicate that the excitatory mechanism of pallidal neurons by glutamate is mediated at least partly through mGluR1. The effects of the mGluR1-related agents on neuronal firing in the internal pallidal segment became rather obscure after MPTP treatment. Our results suggest that the specific down-regulation of pallidal and nigral mGluR1alpha in the parkinsonian state may exert a compensatory action to reverse the overactivity of the subthalamic nucleus-derived glutamatergic input that is generated in the disease.

Focal area of ground-glass opacity and ground-glass opacity predominance on thin-section CT: Discrimination between neoplastic and non-neoplastic lesions

AIM

To reveal differences in thin-section computed tomography (CT) findings between lung neoplastic lesions and non-neoplastic lesions, which showed a focal area of ground-glass opacity or ground-glass opacity predominance.

MATERIALS AND METHODS

A total of 82 focal areas of ground-glass opacity and ground-glass opacity predominance, consisting of 38 neoplastic and 44 non-neoplastic lesions, were assessed retrospectively regarding their thin-section CT findings.

RESULTS

The frequency of wholly well-defined margin (p=0.001), spiculation (p=0.019), pleural indentation (p=0.016), air bronchograms (p=0.027), air-containing space (p=0.004) was significantly higher in neoplastic lesions than in non-neoplastic lesions. Thirty-four of 38 (89%) neoplastic lesions were well-defined in more than 50% of the circumference, of which nine had an air-containing space other than air bronchogram, whereas only one non-neoplastic lesion had these features.

CONCLUSION

A focal area of ground-glass opacity or ground-glass opacity predominance with a well-defined margin and air-containing space is more likely to be a neoplasm.

Mechanism of the CO oxidation reaction on O-precovered Pt(111) surfaces studied with near-edge x-ray absorption fine structure spectroscopy

The mechanism of CO oxidation reaction on oxygen-precovered Pt(111) surfaces has been studied by using time-resolved near-edge x-ray absorption fine structure spectroscopy. The whole reaction process is composed of two distinct paths: (1) a reaction of isolated oxygen atoms with adsorbed CO, and (2) a reaction of island-periphery oxygen atoms after the CO saturation. CO coadsorption plays a role to induce the dynamic change in spatial distribution of O atoms, which switches over the two reaction paths. These mechanisms were confirmed by kinetic Monte Carlo simulations. The effect of coadsorbed water in the reaction mechanism was also examined.

Role of Ionotropic Glutamatergic and GABAergic Inputs on the Firing Activity of Neurons in the External Pallidum in Awake Monkeys

The neurons in the external segment of the pallidum (GPe) in awake animals maintain a high level of firing activity. The level and pattern of the activity change with the development of basal ganglia disorders including parkinsonism and hemiballism. The GPe projects to most of the nuclei in the basal ganglia. Thus exploring the mechanisms controlling the firing activity is essential for understanding basal ganglia function in normal and pathological conditions. To explore the role of ionotropic glutamatergic and GABAergic inputs to the GPe, unit recordings combined with local injections of receptor antagonists were performed in awake monkeys. Observations on the effects of local application of the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)/kainate antagonist 1,2,3,4-tetrahydro-6-nitro-2, 3-dioxo-benzo[f]quinoxaline-7-sulfonamide, the N-methyl-d-aspartic acid (NMDA) antagonist 3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid, and the GABAA antagonist gabazine as well as the effects of muscimol blockade of the subthalamic nucleus on the spontaneous firing rate, firing patterns, and cortical stimulation induced responses in the GPe suggested the following: sustained glutamatergic and GABAergic inputs control the level of the spontaneous firing of GPe neurons; both AMPA/kainate and NMDA receptors are activated by glutamatergic inputs; some GPe neurons receive glutamatergic inputs originating from areas other than the subthalamic nucleus; no GPe neurons became silent after a combined application of glutamate and GABA antagonists, suggesting that GPe neurons have intrinsic properties or nonionotropic glutamatergic tonic inputs that sustain a fast oscillatory firing or a combination of a fast and a slow oscillatory firing in GPe neurons.

Reaction-path switching induced by spatial-distribution change of reactants: CO oxidation on Pt(111)

We studied the mechanism of CO oxidation on O-covered Pt(111) surfaces during CO exposure by means of time-resolved near edge x-ray absorption fine structure spectroscopy. Two distinct reaction processes were found to occur sequentially; isolated O atoms and island-periphery O atoms contribute to each process. Combination of in situ monitoring of the reaction kinetics and Monte Carlo simulations revealed that CO coadsorption plays a role of inducing the dynamic change in spatial distribution of O atoms, which switches over the two reaction paths.

Organization of prefrontal outflow toward frontal motor-related areas in macaque monkeys

Linkage between the prefrontal cortex and the primary motor cortex is mediated by nonprimary motor-related areas of the frontal lobe. In an attempt to analyse the organization of the prefrontal outflow from area 46 toward the frontal motor-related areas, we investigated the pattern of projections involving the higher-order motor-related areas, such as the presupplementary motor area (pre-SMA) and the rostral cingulate motor area (CMAr). Tracer injections were made into these motor-related areas (their forelimb representation) on the medial wall that had been identified electrophysiologically. The following data were obtained from a series of tract-tracing experiments in Japanese monkeys. (i) Only a few neurons in area 46 were retrogradely labelled from the pre-SMA and CMAr; (ii) terminal labelling from area 46 occurred sparsely in the pre-SMA and CMAr; (iii) a dual labelling technique revealed that the sites of overlap of anterograde labelling from area 46 and retrograde labelling from the pre-SMA and CMAr were evident in the rostral parts of the dorsal and ventral premotor cortices (PMdr and PMvr); (iv) and tracer injections into the PMdr produced neuronal cell labelling in area 46 and terminal labelling in the pre-SMA and CMAr. The present results indicate that a large portion of the prefrontal signals from area 46 is not directly conveyed to the pre-SMA and CMAr, but rather indirectly by way of the PMdr and PMvr. This suggests that area 46 exerts its major influence on the cortical motor system via these premotor areas.

Excitatory GABA input directly drives seizure-like rhythmic synchronization in mature hippocampal CA1 pyramidal cells

GABA, which generally mediates inhibitory synaptic transmissions, occasionally acts as an excitatory transmitter through intense GABA(A) receptor activation even in adult animals. The excitatory effect results from alterations in the gradients of chloride, bicarbonate, and potassium ions, but its functional role still remains a mystery. Here we show that such GABAergic excitation participates in the expression of seizure-like rhythmic synchronization (afterdischarge) in the mature hippocampal CA1 region. Seizure-like afterdischarge was induced by high-frequency synaptic stimulation in the rat hippocampal CA1-isolated slice preparations. The hippocampal afterdischarge was completely blocked by selective antagonists of ionotropic glutamate receptors or of GABA(A) receptor, and also by gap-junction inhibitors. In the CA1 pyramidal cells, oscillatory depolarizing responses during the afterdischarge were largely dependent on chloride conductance, and their reversal potentials (average -38 mV) were very close to those of exogenously applied GABAergic responses. Moreover, intracellular loading of the GABA(A) receptor blocker fluoride abolished the oscillatory responses in the pyramidal cells. Finally, the GABAergic excitation-driven afterdischarge has not been inducible until the second postnatal week. Thus, excitatory GABAergic transmission seems to play an active functional role in the generation of adult hippocampal afterdischarge, in cooperation with glutamatergic transmissions and possible gap junctional communications. Our findings may elucidate the cellular mechanism of neuronal synchronization during seizure activity in temporal lobe epilepsy.

Organization of inputs from cingulate motor areas to basal ganglia in macaque monkey

The cingulate motor areas reside within regions lining the cingulate sulcus and are divided into rostral and caudal parts. Recent studies suggest that the rostral and caudal cingulate motor areas participate in distinct aspects of motor function: the former plays a role in higher-order cognitive control of movements, whereas the latter is more directly involved in their execution. Here, we investigated the organization of cingulate motor areas inputs to the basal ganglia in the macaque monkey. Identified forelimb representations of the rostral and caudal cingulate motor areas were injected with different anterograde tracers and the distribution patterns of labelled terminals were analysed in the striatum and the subthalamic nucleus. Corticostriatal inputs from the rostral and caudal cingulate motor areas were located within the rostral striatum, with the highest density in the striatal cell bridges and the ventrolateral portions of the putamen, respectively. There was no substantial overlap between these input zones. Similarly, a certain segregation of input zones from the rostral and caudal cingulate motor areas occurred along the mediolateral axis of the subthalamic nucleus. It has also been revealed that corticostriatal and corticosubthalamic input zones from the rostral cingulate motor area considerably overlapped those from the presupplementary motor area, while the input zones from the caudal cingulate motor area displayed a large overlap with those from the primary motor cortex. The present results indicate that a parallel design underlies motor information processing in the cortico-basal ganglia loop derived from the rostral and caudal cingulate motor areas.

Two-dimensional thick-slice MR digital subtraction angiography for assessment of cerebrovascular occlusive diseases

Although spatial resolution of current MR angiography is excellent, temporal resolution has remained unsatisfactory. We evaluated clinical applicability of 2D thick-slice, contrast-enhanced subtraction MR angiography (2D-MR digital subtraction angiography) with sub-second temporal resolution in cerebrovascular occlusive diseases. Twenty-five patients with cerebrovascular occlusive diseases (8 moyamoya diseases, 10 proximal internal carotid occlusions, and 2 sinus thromboses ) were studied with a 1.5-T MR unit. The MR digital subtraction angiography (MRDSA) was performed per 0.97 s continuously just after a bolus injection of 15 ml of gadolinium chelates up to 40 s in sagittal (covering hemisphere) or coronal planes. Subtraction images were generated at a workstation. We evaluated imaging quality and hemodynamic information of MRDSA in comparison with those of routine MR imaging, non-contrast MR angiography, and X-ray intra-arterial DSA. Major cerebral arteries, all of the venous sinuses, and most tributaries were clearly visualized with 2D MRDSA. Also, pure arterial phases were obtained in all cases. The MRDSA technique demonstrated prolonged circulation in sinus thromboses, distal patent lumen of proximal occlusion, and some collateral circulation. Such hemodynamic information was comparable to that of intra-arterial DSA. Two-dimensional thick-slice MRDSA with high temporal resolution has a unique ability to demonstrate cerebral hemodynamics equivalent to that of intra-arterial DSA and may play an important role for evaluation of cerebrovascular occlusive diseases.

A case of abnormal pancreaticobiliary junction evidenced by 3D drip infusion cholangiography CT

We report a case of abnormal pancreaticobiliary junction (APBJ), in which three-dimensional (3D) drip infusion cholangiography (DIC) computed tomography (CT) was useful to make the diagnosis. The 3D DIC CT clearly demonstrated reflux of the contrast material into the main pancreatic duct as well as a long common channel, dilated biliary tree, and duodenal lumen. Thereby, we could diagnose APBJ. We believe that 3D DIC CT is a valuable method in the evaluation of patients with suspected APBJ.

Somatotopic arrangement and corticocortical inputs of the hindlimb region of the primary motor cortex in the macaque monkey

Using Japanese monkeys, we examined the somatotopic organization of the hindlimb region of the primary motor cortex (MI) with intracortical microstimulation. In the hindlimb region of the MI, areas representing distal movements (digits and ankle joints) were basically surrounded by those representing proximal movements (knee and hip joints). Thus, the hindlimb region of the MI has a nested or horseshoe-like somatotopic representation. We then examined the topographic organization of corticocortical projections to the hindlimb region of the MI by the retrograde double-labeling technique: one monkey received paired injections of Fast blue (FB) and Diamidino yellow (DY) into hindlimb or forelimb representation of the MI, respectively, while two monkeys received those of FB and DY into proximal or distal representation of the hindlimb region of the MI, respectively. The neurons projecting to the hindlimb region of the MI were located in cortical areas largely separate from those projecting to the forelimb region of the MI. On the other hand, we found a substantial overlap of corticocortical neurons projecting to the proximal and distal parts of the hindlimb region of the MI in the dorsal division of the premotor cortex and the cingulate motor areas.

Organization of somatic motor inputs from the frontal lobe to the pedunculopontine tegmental nucleus in the macaque monkey

To reveal the somatotopy of the pedunculopontine tegmental nucleus that functions as a brainstem motor center, we examined the distribution patterns of corticotegmental inputs from the somatic motor areas of the frontal lobe in the macaque monkey. Based on the somatotopical map prepared by intracortical microstimulation, injections of the anterograde tracers, biotinylated dextran amine and wheat germ agglutinin-conjugated horseradish peroxidase, were made into the following motor-related areas: the primary motor cortex, the supplementary and presupplementary motor areas, the dorsal and ventral divisions of the premotor cortex, and the frontal eye field. Data obtained from the present experiments were as follows: (i) Corticotegmental inputs from orofacial, forelimb, and hindlimb representations of the primary motor cortex tended to be arranged orderly from medial to lateral in the pedunculopontine tegmental nucleus. However, the distribution areas of these inputs considerably overlapped; (ii) The major input zones from distal representations of the forelimb and hindlimb regions of the primary motor cortex were located medial to those from their proximal representations, although there was a substantial overlap between the distribution areas of distal versus proximal limb inputs; (iii) The main terminal zones from the forelimb regions of the primary motor cortex, the supplementary and presupplementary motor areas, and the dorsal and ventral divisions of the premotor cortex appeared to overlap largely in the mediolaterally middle aspect of the pedunculopontine tegmental nucleus; and (iv) Corticotegmental input from the frontal eye field was scattered over the pedunculopontine tegmental nucleus.Thus, the present results indicate that the pedunculopontine tegmental nucleus is likely to receive partly separate but essentially convergent cortical inputs not only from multiple motor-related areas representing the same body part, but also from multiple regions representing diverse body parts. This suggests that somatotopical representations are intermingled rather than segregated in the pedunculopontine tegmental nucleus.

Time-resolved two-dimensional thick-slice magnetic resonance digital subtraction angiography in assessing brain tumors

The aim of this study was to evaluate clinical applicability of two-dimensional (2D) thick-slice, contrast-enhanced magnetic resonance digital subtraction angiography (MRDSA) with high temporal resolution in diagnosis of brain tumors. Forty-four patients with brain tumors including, 15 meningiomas, 8 gliomas, 6 metastatic tumors, 4 neuromas, and 2 hemangioblastomas, were studied with 2D MRDSA with frame rate approximately 1 s. Images were continuously obtained following the initiation of bolus injection of gadolinium chelates for 40 s and subtraction images were generated in a workstation. We evaluated visualization of normal cranial vessels on MRDSA and compared MRDSA and intra-arterial digital subtraction angiography (IADSA) with regard to hemodynamic information. Large cerebral arteries, all venous sinuses, and most tributaries were clearly visualized. A stain was present in hypervascular tumors including all 15 meningiomas and 2 hemangioblastomas on MRDSA. Presence of a stain demonstrated on MRDSA and that on IADSA coincided in 16 of 20 cases (Spearman rank correlation value was 0.85). The location, shape, and phase of the stain on MRDSA were similar to those on IADSA. Two-dimensional MRDSA with high temporal resolution has a unique ability to demonstrate cerebral hemodynamics, such as IADSA, and can play an important role in assessing brain tumors.

Excitatory cortical inputs to pallidal neurons via the subthalamic nucleus in the monkey

How the motor-related cortical areas modulate the activity of the output nuclei of the basal ganglia is an important issue for understanding the mechanisms of motor control by the basal ganglia. In the present study, by using awake monkeys, the polysynaptic effects of electrical stimulation in the forelimb regions of the primary motor and primary somatosensory cortices on the activity of globus pallidus (GP) neurons, especially mediated by the subthalamic nucleus (STN), have been characterized. Cortical stimulation induced an early, short-latency excitation followed by an inhibition and a late excitation in neurons of both the external and internal segments of the GP. It also induced an early, short-latency excitation followed by a late excitation and an inhibition in STN neurons. The early excitation in STN neurons preceded that in GP neurons. Blockade of STN neuronal activity by muscimol (GABA(A) receptor agonist) injection resulted in abolishment of both the early and late excitations evoked in GP neurons by cortical stimulation. At the same time, the spontaneous discharge rate of GP neurons decreased, pauses between the groups of spikes of GP neurons became prominent, and the firing pattern became regular. Injection of (+/-)-3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP) [N-methyl-D-aspartate (NMDA) receptor antagonist], but not 1,2,3, 4-tetrahydro-6-nitro-2,3-dioxo-benzo[f]quinoxaline-7-sulfonamide disodium [NBQX (non-NMDA receptor antagonist)], into the STN attenuated the early and late excitations in GP neurons, suggesting that cortico-subthalamic transmission is mediated mainly by NMDA receptors. Interference with the pallido-subthalamic transmission by bicuculline (GABA(A) receptor antagonist) injection into the STN made the inhibition distinct without affecting the early excitation. The present results indicate that the cortico-subthalamo-pallidal pathway conveys powerful excitatory effects from the motor-related cortical areas to the GP with shorter conduction time than the effects conveyed through the striatum.

Protection against dopaminergic nigrostriatal cell death by excitatory input ablation

The importance of enhanced glutamatergic neurotransmission in the basal ganglia and related structures has recently been highlighted in the development of Parkinson's disease. The pedunculopontine tegmental nucleus (PPN) is the major origin of excitatory, glutamatergic input to dopaminergic nigrostriatal neurons of which degeneration is well known to cause Parkinson's disease. Based on the concept that an excitatory mechanism mediated by glutamatergic neurotransmission underlies the pathogenesis of neurodegenerative disorders, we made an attempt to test the hypothesis that removal of the glutamatergic input to the nigrostriatal neurons by PPN lesions might prevent 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced parkinsonism in the macaque monkey. The PPN was lesioned unilaterally with microinjection of kainic acid, and, then, MPTP was administered systemically. In these monkeys, the degree of parkinsonian motor signs was behaviourally evaluated, and the histological changes in the dopaminergic nigrostriatal system were analysed by means of tyrosine hydroxylase immunohistochemistry. The present results revealed that nigrostriatal cell loss and parkinsonian motor deficits were largely attenuated in the MPTP-treated monkey group whose PPN had been lesioned, compared with the control, MPTP-treated monkey group with the PPN intact. This clearly indicates that the onset of MPTP neurotoxicity is suppressed or delayed by experimental ablation of the glutamatergic input to the nigrostriatal neurons. Such a protective action of excitatory input ablation against nigrostriatal cell death defines evidence that nigral excitation driven by the PPN may be implicated in the pathophysiology of Parkinson's disease.

B-mode and color Doppler ultrasound imaging for localization of microelectrode in monkey brain

Using alert monkeys, we attempted ultrasound imaging after partial craniotomy to localize a metal microelectrode in the brain. B-mode ultrasonography provided images of sulcus and gyrus patterns of the cerebral cortex, and locations of the ventricles and subarachnoid cisterns. As the microelectrode proceeded in the brain, the position of the microelectrode was clearly identified. Electrolytic microlesions generated by delivering direct currents via the microelectrode could also be detected. Color Doppler imaging of blood vessels of the brain was helpful to demarcate deep brain structures and to avoid accidental injury of the blood vessels by the microelectrode. The ultrasonography will make it possible to place recording microelectrodes or injection needles accurately in target regions of the brain in physiological, anatomical or behavioral experiments.

A cortical motor region that represents the cutaneous back muscles in the macaque monkey

A cortical motor region that represented the cutaneous muscles on the back was identified on the medial wall of the frontal lobe in the macaque monkey. In this region, neurons responded to somatosensory stimuli such as light touch or squeezing of the back skin, and intracortical microstimulation elicited contraction of the back skin. Such a region was located primarily on the dorsal bank of the cingulate sulcus, corresponding to the dorsal cingulate motor area.

Various imaging modalities for the detection of salivary gland lesions: the advantages of 201Tl SPET

The aim of this study was to compare dual-isotope (99Tc(m) and 201Tl) SPET imaging with computed tomography (CT) and magnetic resonance imaging (MRI) in the differentiation of various lesions of the major salivary glands. Twenty-two patients underwent dual-isotope SPET imaging, of whom 12 also had CT and 15 also had an MRI study. The uptake ratio and retention index for 99Tc(m) and 201Tl were calculated by drawing regions of interest on the involved and normal glands. Both CT and MRI were interpreted by two radiologists. All malignant tumours were detected by all three modalities. Warthin's tumours were detected by dual-isotope SPET imaging; however, MRI failed to differentiate Warthin's tumour from pleomorphic adenoma. Of 13 other benign tumours, dual-isotope SPET correctly diagnosed 12. Of 16 tumours showing a cold defect on the 99Tc(m) images, parametric analysis with 201Tl gave an accuracy of 94%, whereas CT gave an accuracy of 70-90%. MRI was 73-91% accurate in differentiating between benign (Warthin's) and malignant tumours. We believe that dual-isotope SPET imaging (99Tc(m) and 201Tl), together with semi-quantitative analysis, is the method of choice for differentiating between various lesions of the major salivary glands.

Detection of hepatocellular carcinoma and its metastases with various pulse sequences using superparamagnetic iron oxide (SHU-555-A)

BACKGROUND

To identify the most useful combinations of various pre- and postcontrast magnetic resonance (MR) image sequences in detecting hepatocellular carcinoma (HCC) and its intrahepatic metastases before and after injection of SHU-555-A.

METHODS

Thirty-eight lesions in 16 patients were evaluated before and after administration of SHU-555-A by using fast spin echo (FSE), gradient echo (GRE), and echo planar (EP) imaging sequences using a 1.5-Tesla superconducting MR system. The signal intensity ratio (SIR) and contrast-to-noise ratio (CNR) of the lesions, signal-to-noise ratios, and other parameters were calculated.

RESULTS

Tumors were better detected after injection of SHU-555-A on all pulse sequences except on out-of-phase T1-weighted (T1W)-GRE sequences. Tumor detectability was higher for precontrast EP imaging and T2*-weighted (T2*W)-GRE sequences, whereas detectability at postcontrast was higher for T2*W-GRE, proton-density-weighted-FSE, and in-phase T1W-GRE sequences. The SIR and CNR at precontrast were highest for EP imaging, and those at postcontrast were highest for T2*W-GRE.

CONCLUSION

SHU-555-A will increase the detectability of HCC and its liver metastases. T1W- and T2*W-GRE sequences would be the sequences of choice.

Direct projections from the magnocellular division of the basal nucleus of the amygdala to the principal part of the cortical masticatory area in the macaque monkey

Direct projections from the amygdala to the cortical masticatory area were found in the macaque monkey. Under the guidance of intracortical microstimulation, retrograde tracers were injected into multiple jaw movement-related regions of the frontal lobe. The cortical masticatory area, especially its principal part, stimulation of which elicited rhythmic jaw movement, was the only site of injection that produced neuronal labeling in the amygdala. The cells of origin of such projections were localized in the medial aspect of the magnocellular division of the basal nucleus through its rostral level. No labeled neurons were observed in the amygdala after tracer injection into any other cortical jaw movement-related region. The present results suggest that the amygdaloid input to the cortical masticatory area may exert some modulatory influence on the generation of masticatory rhythm.

Effect of concurrent intra-arterial infusion of platinum drugs for patients with stage III or IV uterine cervical cancer treated with radical radiation therapy

PURPOSE

The purpose of this study was to explore the effect of concurrent intra-arterial infusion of platinum drugs in patients with stage III or IV uterine cervical cancer treated with radical radiation therapy.

PATIENTS AND METHODS

Thirty-three patients with advanced (stage IIIA, 2; IIIB, 28; IVA, 3) uterine cervical squamous cell carcinoma were randomized into a concurrent intra-arterial infusion of platinum drugs with radiation therapy (IAPRT) group (18 patients) and a radiation therapy alone group (15 patients). After altering intrapelvic blood flow by embolization of the superior and inferior gluteal arteries under pelvic angiography, intra-arterial infusion of platinum drug through catheters inserted into both internal iliac arteries was performed concurrently with radiation therapy. One-shot infusion of cisplatin (100 mg/m2) twice with a 2- to 3-week interval was performed in eight patients, weekly infusion of carboplatin (100 mg/m2) via a reservoir five to six times was performed in four patients, and daily shot of cisplatin (10 mg/body) or 21 days via a reservoir was performed in six patients. Radiation therapy consisted of external-beam irradiation of 50 Gy/25 fractions/5 weeks for the whole pelvis with midline block after 30 Gy and intracavitary high-dose-rate brachytherapy using tandem and ovoids of 24 Gy/4 fractions/4 weeks to point A.

RESULTS

The local complete response rate of the IAPRT group was 94% and was significantly higher than that of the radiation therapy group (67%). There were no significant differences in local response in the three drug delivery methods. Two- and 5-year overall survival rates were 54.5% and 44.4% in the IAPRT group, and 74.5% and 50.0% in the radiation therapy group, respectively. There was no significant difference between the two groups. In the IAPRT group, grade 3 or 4 acute bowel complications were seen in 33% of patients, grade 3 or 4 late bowel complications were seen 44%, and grade 3 or 4 myelosuppression was seen in 33%, and these complications were seen more in the IAPRT group than in the radiation therapy group and caused death in some patients.

CONCLUSIONS

IAPRT had a better local response than radiation therapy but showed no proof of control over recurrence and had a poorer survival than radiation therapy. There were many local recurrences and distant metastases, contrary to the better first response of the IAPRT group over the radiation therapy group. Complications of the IAPRT group were very severe and made the patient's performance status and prognosis worse than in the radiation therapy group. We need to design some methods to decrease these complications to make use of the good local response acquired with IAPRT. Furthermore, we should re-examine the indication of IAPRT in patients with a large tumor because local recurrence and distant metastasis would be inevitable.

Organization of nonprimary motor cortical inputs on pyramidal and nonpyramidal tract neurons of primary motor cortex: An electrophysiological study in the macaque monkey

To elucidate the functions of nonprimary motor cortical (nPMC) areas whose afferents synapse onto output neurons of the primary motor cortex (PMC), we examined the responses of pyramidal tract neurons (PTNs) and non-PTNs (nPTNs) to electrical stimulation in the three nPMCs, the supplementary motor area (SMA) and the dorsal and ventral divisions of the premotor cortex (PMd and PMv), with extracellular unit recording in alert monkeys. Typical responses of PTNs to nPMC stimulation were early orthodromic excitatory responses followed by inhibitory responses. Among 27 PTNs tested by constructing peri-stimulus time histograms, 19 (70.4%) showed inhibitory responses to stimulation in all of the nPMC areas. In contrast, 5/33 PTNs (15.2%) and 10/72 nPTNs (13.9%) showed excitatory responses to stimulation in all of the nPMCs. The inhibitory responses of PTNs were mediated by inhibitory interneurons, some of which may correspond to nPTNs in the superficial layers of the PMC. These interneurons probably possess widely extended axons and nonspecifically inhibit multiple PTNs in layer V. The excitatory and inhibitory influences, and the patterns of convergence of inputs from the nPMCs onto the PTNs, are important to understand motor control by the nPMC-PMC-spinal cord pathway.

Corticostriatal and corticosubthalamic input zones from the presupplementary motor area in the macaque monkey: comparison with the input zones from the supplementary motor area

The presupplementary motor area (pre-SMA) is a cortical motor-related area which lies in the medial wall of the frontal lobe, immediately anterior to the supplementary motor area (SMA). This area has been considered to participate in the control of complex forelimb movements in a way different from the SMA. In an attempt to analyze the patterns of projections from the pre-SMA to the basal ganglia, we examined the distributions of pre-SMA inputs in the striatum and the subthalamic nucleus and compared them with the SMA input distributions. To detect morphologically the terminal fields from the pre-SMA and the forelimb region of the SMA, anterograde tracers were injected into such areas that had been identified electrophysiologically in the macaque monkey. Corticostriatal inputs from the pre-SMA were distributed mainly in the striatal cell bridges connecting the rostral aspects of the caudate nucleus and the putamen, as well as in their neighboring striatal portions. These input zones were located, with no substantial overlap, rostral to corticostriatal input zones from the SMA forelimb region. Corticosubthalamic input zones from the pre-SMA were almost localized in the medial aspect of the nucleus, where corticosubthalamic inputs from the SMA forelimb region were also distributed predominantly. However, the major terminal fields from the pre-SMA were centered ventrally to those from the SMA. The present results indicate that the corticostriatal and corticosubthalamic input zones from the pre-SMA appear to be segregated from the SMA-derived input zones. This implies the possibility of parallel processing of motor information from the pre-SMA and SMA in the cortico-basal ganglia circuit.

Corticostriatal projections from distal and proximal forelimb representations of the monkey primary motor cortex

Corticostriatal projections from one distal and two proximal subregions in the forelimb representation of the primary motor cortex (MI) were examined in the macaque monkey. The distal and proximal subregions in the anterior bank of the central sulcus (distal and proximal-bank subregions) and the proximal subregion in the surface of the precentral gyrus (proximal-surface subregion) of the MI were identified using intracortical microstimulation. Different anterograde tracers were then injected into two of these three forelimb subregions of the MI. In the ipsilateral putamen, the distribution areas of corticostriatal fibers from the distal, proximal-bank and proximal-surface subregions were arranged from ventrolateral to dorsomedial in this order. These corticostriatal input zones were largely segregated from one another.

Monkey globus pallidus external segment neurons projecting to the neostriatum

Experiments were performed to assess the number and parvalbumin (PV) immunoreactivity of neurons participating in the pallidostriatal projection in macaque monkeys. Injection of WGA-HRP into the right caudate nucleus and the left putamen of a Macaca mulatta and a M. fuscata labeled a large number of the globus pallidus external segment (GPe) neurons. Counting neurons labeled with WGA-HRP and those stained with neuronal markers indicated that approximately 30% of GPe neurons project to neostriatum. Approximately 2/3 of the pallidostriatal neurons are PV-immunoreactive. This study revealed that a significant number of primate GPe PV immunoreactive neurons project to the neostriatum, and suggest that the pallidostriatal projection should be taken into account in the analysis of functional roles of the basal ganglia circuitry.

[Evaluation of two-dimensional thick-slice MR DSA: preliminary study]

We have used two-dimensional contrast-enhanced MR angiography for a single thick slice and called it MR DSA. This technique realizes nearly subsecond scanning per image and is therefore superior to other types of contrast-enhanced MR angiography in temporal resolution. To determine the optimal parameters of this technique, we calculated SSR (the signal of brain to the signal of contrast agent ratio) in various settings. We also obtained MR DSA images of 26 cases. We believe that MR DSA may play a supportive role in conventional MR imaging or angiography, since its high temporal resolution is of value in the evaluation of cerebrovascular diseases.

[Application of MR-guided intravascular procedures by passive tracking utilizing the magnetic susceptibility effect: a preliminary report]

In MR-guided intravascular procedures, the position of catheters must be confirmed on near-real-time MR images. One way of monitoring this is by passive tracking utilizing the magnetic susceptibility effect. A catheter with a stainless steel braid had suitable visibility when tracked by magnetic susceptibility on fast GRE images, although the direction of the static magnetic field affected the apparent width of the catheter. Passive tracking with a 1.5T MRI unit was performed in a patient at one image/2 seconds with fast GRE. The catheter could be introduced to the SMA and celiac artery from the aorta with passive tracking.

A modified microsyringe for extracellular recording of neuronal activity

We describe a modified Hamilton microsyringe that allows extracellular recording of neuronal activity and subsequent injections. It is assembled with a Hamilton removable needle and a syringe for injection, a Teflon-coated tungsten wire for recording, and polyimide tubing as a sheath. The device is inexpensive and easy to handle in anatomical and physiological experiments in awake monkeys.

Corticostriatal projections from the somatic motor areas of the frontal cortex in the macaque monkey: segregation versus overlap of input zones from the primary motor cortex, the supplementary motor area, and the premotor cortex

It is an important issue to address the mode of information processing in the somatic motor circuit linking the frontal cortex and the basal ganglia. In the present study, we investigated the extent to which corticostriatal input zones from the primary motor cortex (MI), the supplementary motor area (SMA), and the premotor cortex (PM) of the macaque monkey might overlap in the putamen. Intracortical microstimulation was performed to map the MI, SMA, and dorsal (PMd) and ventral (PMv) divisions of the PM. Then, two different anterograde tracers were injected separately into somatotopically corresponding regions of two given areas of the MI, SMA, PMd, and PMv. With respect to the PMd and PMv, tracer injections were centered on their forelimb representations. Corticostriatal input zones from hindlimb, forelimb, and orofacial representations of the MI and SMA were, in this order, arranged from dorsal to ventral within the putamen. Dense input zones from the MI were located predominantly in the lateral aspect of the putamen, whereas those from the SMA were in the medial aspect of the putamen. On the other hand, corticostriatal inputs from forelimb representations of the PMd and PMv were distributed mainly in the dorsomedial sector of the putamen. Thus, the corticostriatal input zones from the MI and SMA were considerably segregated though partly overlapped in the mediolateral central aspect of the putamen, while the corticostriatal input zone from the PM largely overlapped that from the SMA, but not from the MI.

Corticostriatal input zones from the supplementary motor area overlap those from the contra- rather than ipsilateral primary motor cortex

To investigate the degree of convergence of corticostriatal inputs from the primary motor cortex (MI) and the supplementary motor area (SMA), we analyzed the extent to which corticostriatal inputs from forelimb representations of these motor-related areas spatially overlap in the macaque monkey. Of particular interest was that corticostriatal input zones from SMA overlapped those from MI of the contralateral hemisphere more extensively than from MI of the ipsilateral hemisphere.

Corticosubthalamic input zones from forelimb representations of the dorsal and ventral divisions of the premotor cortex in the macaque monkey: comparison with the input zones from the primary motor cortex and the supplementary motor area

Employing double anterograde axonal tracing in combination with intracortical microstimulation, we examined the distribution patterns of corticosubthalamic inputs from forelimb representations of the dorsal (PMd) and ventral (PMv) divisions of the premotor cortex in the macaque monkey. The inputs from the PMd and PMv were distributed mainly in the medial aspect of the subthalamic nucleus (STN), in which their distribution areas overlapped each other. By the same experimental approach, we further compared corticosubthalamic input zones from the PMd/PMv with those from the primary motor cortex (MI) and the supplementary motor area (SMA). The input zones from the PMd/PMv and SMA largely overlapped in the medial aspect of the STN, whereas the input zones from the PMd/PMv and MI were virtually segregated mediolaterally in the STN.

Reevaluation of ipsilateral corticocortical inputs to the orofacial region of the primary motor cortex in the macaque monkey

An anatomical approach to possible areas in the cerebral cortex involved in somatic motor behavior is to analyze the cortical areas containing neurons that connect directly to the primary motor cortex (MI). To define the cortical areas related to orofacial movements, we examined the distribution of cortical neurons that send their axons to the orofacial region of the MI in the macaque monkey. Injections of retrograde tracers into the electrophysiologically identified orofacial region of the MI revealed that labeled neurons were distributed in the following cortical areas: the orbital cortex (area 12), insular cortex, frontoparietal operculum (including the deep part of the cortical masticatory area and the secondary somatosensory cortex), ventral division of the premotor cortex (especially in its lateral part), orofacial region of the supplementary motor area, rostral division of the cingulate motor area (CMA), and CMA on the ventral bank. A number of labeled neurons were also seen in the MI around the injection sites and in the parietal cortex (including the primary somatosensory cortex and area 7b). No labeled neurons were found in the dorsal division of the premotor cortex. Fluorescent retrograde double labeling further revealed virtually no overlap of distribution between cortical neurons projecting to the orofacial and forelimb regions of the MI. Based on the present results, we discuss the functional diversity of the cortical areas related to orofacial motor behavior and the somatotopical organization in the premotor areas of the frontal cortex.