Mechanochemical Synthesis of Perovskite Oxyhydrides: Insights from Shear Modulus

Perovskite oxyhydrides have attracted recent attention due to their intriguing properties such as ionic conductivity and catalysis, but their repertoire is still restricted compared to perovskite oxynitrides and oxyfluorides. Historically, perovskite oxyhydrides have been prepared mostly by topochemical reactions and high-pressure (HP) reactions, while in this study, we employed a mechanochemical (MC) approach, which enables the synthesis of a series of ABO2H-type oxyhydrides, including those with the tolerance factor (t) much smaller than 1 (e.g., SrScO2H with t = 0.936) which cannot be obtained by HP synthesis. The octahedral tilting, often present in perovskite oxides, does not occur, suggesting that the lack of π-symmetry of the H 1s orbital and the large polarization destabilize tilted low-symmetry structures. Interestingly, SrCrO2H (t = 0.997), previously reported with the HP method, was not achieved with the MC method. A comparative analysis revealed a correlation between the feasibility of MC reactions and the (calculated) shear modulus of the starting reagents (binary oxides and hydrides). Notably, this indicator is not exclusive to oxyhydride perovskites but extends to oxide perovskites (SrMO3). This study demonstrates that MC synthesis offers unique opportunities not only to expand the compositional space in oxyhydrides in various structural types but also to provide a guide for the choice of starting materials for the synthesis of other compounds.

Ammonia Synthesis via an Associative Mechanism on Alkaline Earth Metal Sites of Ca3 CrN3 H

Typically, transition metals are considered as the centers for the activation of dinitrogen. Here we demonstrate that the nitride hydride compound Ca3 CrN3 H, with robust ammonia synthesis activity, can activate dinitrogen through active sites where calcium provides the primary coordination environment. DFT calculations also reveal that an associative mechanism is favorable, distinct from the dissociative mechanism found in traditional Ru or Fe catalysts. This work shows the potential of alkaline earth metal hydride catalysts and other related 1 D hydride/electrides for ammonia synthesis.

Morphological changes and cellular dynamics of oligodendrocyte lineage cells in the developing vertebrate central nervous system

Oligodendrocyte precursor cells (OPCs) originate in multiple restricted regions of the developing central nervous system (CNS). Here, we focus on morphological changes of oligodendrocyte lineage cells and their cellular dynamics including cell motility and proliferation. Morphological studies with molecular markers for OPCs suggest distinct spatiotemporal patterns of OPC migration in vivo, which are directly demonstrated by application of exogenous fluorescent markers to OPCs. Extensive proliferation of OPCs in the CNS parenchyma is also demonstrated by pulse labeling of the cells with bromodeoxyuridine. The results strongly suggest that oligodendrocyte lineage cells are highly motile and actively proliferate with an elongated morphology. These data provide insights into the potential molecular mechanisms of OPC dispersal throughout the CNS.

Projections from the red nucleus to the parvicellular reticular formation and the cervical spinal cord in the rat, with special reference to innervation by branching axons

After biotinylated dextranamine injection into the dorsal part of the red nucleus (RN) in the rat, labeled axons were distributed contralaterally in the lateral tegmental field including the parvicellular reticular formation (RFp), and ipsilaterally in the medial reticular formation. In the cervical spinal cord, labeled axons were present bilaterally with a contralateral dominance mainly in laminae V-VI and the dorsal part of laminae VII. After ipsilateral injections of rhodamine dextranamine, Fluoro-ruby (FR) into the RFp and Fluoro-gold (FG) into the upper cervical spinal cord, a population of FR-labeled neurons was found in the dorsal part of the contralateral RN, whereas the majority of FG-labeled neurons were located more ventrally. However, some of them were intermingled with FR-labeled neurons, and as many as one-third of FR-labeled neurons were labeled with FG. After combined injections of FR into the RFp and FG into the lower cervical spinal cord, RN neurons labeled with FG existed more ventrally than those retrogradely labeled from the upper cervical spinal cord, and less than 10% of FR-labeled neurons were labeled with FG. The present data suggest that axon collateral innervation of the RFp and the upper cervical spinal cord by single RN neurons may be responsible for coordinating head and orofacial movements.

Organization of projections from the medial agranular cortex to the superior colliculus in the rat: a study using anterograde and retrograde tracing methods

The organization of corticotectal projections from the medial agranular cortex (AGm), which has been considered to contain rat's frontal eye field, was examined using anterograde and retrograde tracing techniques. When biotinylated dextranamine (BDA) injections were made into the rostral part of the AGm, small numbers of BDA-labeled axons were found in the rostral two-thirds of the superior colliculus (SC) while some labeled axons were seen in the caudal one-third of the SC. These labeled axons were distributed mainly in the lateral part of the stratum griseum intermediale. On the other hand, after BDA injections into the caudal part of the AGm, moderate to dense plexuses of labeled axons were found in the rostral two-thirds of the SC while some labeled axons were seen in the caudal one-third of the SC. These labeled axons were distributed in the ventromedial and dorsolateral marginal zones of the stratum griseum intermediale as well as in the stratum griseum profundum. The corticotectal projections were largely uncrossed. After combined injections of BDA into the caudal part of the AGm on one side and cholera toxin B subunit (CTb) into the paramedian pontine reticular formation on the opposite side or into the interstitial nucleus of Cajal on the same side, the overlapping distributions of BDA-labeled axons and CTb-labeled neurons were found in the ventromedial marginal zone of the stratum griseum intermediale ipsilateral to the site of BDA injection. These results suggest that the caudal part of the AGm plays a more significant role in the oculomotor function than does the rostral part of the AGm.

Extensive proliferation of oligodendrocyte precursors in the parenchyma of the embryonic chick central nervous system

The proliferation of oligodendrocyte lineage cells in the chick embryo central nervous system (CNS) was examined by double-immunolabeling with a lineage marker monoclonal antibody (mAb) O4 or mAb O1 and 5-bromo-3'-deoxyuridine (BrdU). In all regions examined, the first O4-positive (O4+) cells appeared in restricted regions of the ventricular zone (VZ), regarded as a site of oligodendrocyte origin. Within the O4+ focus, less than 20% of the O4+ cells incorporated BrdU. In contrast, O4+ cells in the parenchyma were mitotically active; for example, 40-50% of early O4+ cells were labeled with BrdU. Some of these were unipolar in shape, indicative of migratory precursor cells. The frequency of O4+/BrdU+ cell appearance decreased to less than 20% with further development. O1+ oligodendrocytes were largely mitotically inactive, with only approximately 5% of O1+ cells incorporating BrdU. These results clearly demonstrated that the VZ generates relatively few precursor cells and that these oligodendrocyte precursors actively generate their cohort in the parenchyma of the CNS.

Phrenic motoneurons receive monosynaptic inputs from the Kölliker-Fuse nucleus: a light- and electron-microscopic study in the rat

The parabrachial complex, which plays an important role in respiratory regulation, has been reported to send projection fibers to the phrenic nucleus, but the synaptic organization between the parabrachial fibers and the phrenic motoneurons has not been examined. Using anterograde and retrograde tracing methods, we found in the rat that the parabrachial fibers originating mainly from the Kölliker-Fuse nucleus (KF) terminated not only within the phrenic nucleus but also on the radial dendritic bundles of the phrenic motoneurons. It was further revealed that the KF fibers made asymmetrical synapses predominantly with dendrites and partly with somata of the phrenic motoneurons. These data suggest that output signals from the KF may exert excitatory influence directly upon the phrenic motoneurons.

Morphological evidence for a vestibulo-thalamo-striatal pathway via the parafascicular nucleus in the rat

We observed by anterograde and retrograde tracing techniques that projection fibers originating from the medial vestibular nucleus (MVe) of the rat terminated in the dorsal two-thirds of the lateral part of the parafascicular thalamic nucleus (PF), where neurons sending their axons to the dorsolateral part of the striatum existed. It was further revealed that the vestibular fibers made asymmetrical synaptic contacts mainly with dendrites and additionally with soma of the striatum-projecting PF neurons. These data suggest that output signals from the MVe may be transmitted disynaptically to the striatal neurons via the PF neurons.

Topographical organization of projections from the subiculum to the hypothalamus in the rat

The projections from the subiculum to the hypothalamus were comprehensively examined in the rat by using the anterograde Phaseolus vulgaris leucoagglutinin (PHA-L) and retrograde cholera toxin B subunit (CTb) methods. Tracing of efferents with PHA-L indicated that the medial preoptic region received projection fibers from the temporal two-thirds of the subiculum, whereas the anterior, tuberal, and mammillary regions received those from the full longitudinal extent of the subiculum. The subicular projections to the anterior and tuberal hypothalamic regions were also found to be organized in a topographical manner such that the temporal-to-septal axis of origin in the subiculum determined a ventromedial-to-dorsolateral axis of termination in the medial zone of the hypothalamus: Massive labeled fibers from the temporalmost part of the subiculum terminated in the subparaventricular zone and its caudal continuum around the dorsal and medial aspects of the ventromedial nucleus, and those from progressively more septal parts terminated in progressively more dorsolateral parts of the medial zone. In addition, the temporal-to-septal axis of origin in the subiculum tended to determine a medial-to-lateral axis of termination in the preoptic region as well as a ventral-to-dorsal axis of termination in the mammillary region. Furthermore, the temporal-to-septal axis of origin in the septal two-thirds of the subiculum corresponded to a ventrolateral-to-dorsomedial axis of termination in the medial mammillary nucleus. The topographical projections from the subiculum to the medial zone of the hypothalamus were confirmed by CTb experiments, representatively in the subicular projections to the anterior hypothalamic region. These results suggest that different populations of neurons existing along the longitudinal axis of the subiculum may exert their influences on the execution of different hypothalamic functions.

Monosynaptic and disynaptic projections from the substantia nigra pars reticulata to the parafascicular thalamic nucleus in the rat

We examined a direct pathway and an indirect pathway via the reticular thalamic nucleus (RT) from the substantia nigra pars reticulata (SNr) to the parafascicular thalamic nucleus (PF) by using anterograde and retrograde tract tracing methods. After biotinylated dextranamine (BDA) injection into the dorsolateral part of the SNr, many labeled fibers and axon terminals were distributed in the ventral part of the RT, as well as in the ventrolateral part of the PF, bilaterally with an ipsilateral dominance. After BDA injection into the ventral part of the RT, a plexus of labeled axons was found bilaterally with an ipsilateral dominance in the ventrolateral part of the PF. After combined injections of BDA into the dorsolateral part of the SNr and cholera toxin B subunit (CTb) into the ventrolateral part of the PF on the same side, overlapping distribution of BDA-labeled fibers and CTb-labeled neurons was observed in the ventral part of the RT ipsilateral to the injection sites, where the BDA-labeled axon terminals made symmetrical synaptic contacts with soma and dendrites of the CTb-labeled neurons.

Development of macroglial cells in the embryonic chick optic nerve

Macroglia development in the embryonic chick optic nerve was immunohistochemically examined. The astrocytes with glial fibrillary acidic protein immunoreactivity were initially restricted to the retinal end of the optic nerve at stage 40, but had widely dispersed within the optic nerve in an out-side-in manner by stage 44. Oligodendrocytes with myelin basic protein immunoreactivity appeared at stage 38, and were widely distributed at stage 40. Electron microscopic observation confirmed the presence of intermediate filaments in the glial fibers and developing myelin at stages 40-41. The present results suggest that oligodendrocyte precursors undergo terminal differentiation slightly earlier than astrocyte precursors with respect to the expression of marker proteins.

Tectal projections to the parvicellular reticular formation and the upper cervical spinal cord in the rat, with special reference to axon collateral innervation

After Phaseolus vulgaris leucoagglutinin injection into the lateral part of the superior colliculus (SC) in the rat, labeled fibers and axon terminals in the lower brainstem were distributed not only in the medial reticular formation but also in the lateral tegmental field including the parvicellular reticular formation (RFp). More caudally, in the upper cervical spinal cord labeled fibers with bouton-like varicosities were distributed mainly in laminae V, VII and VIII, with relatively sparse distribution in lamina IX. These labeled axons were found bilaterally with a clear-cut contralateral dominance. After combined injections of rhodamine-dextranamine, Fluoro-ruby (FR) into the RFp and Fluoro-gold (FG) into the upper cervical spinal cord on the same side, SC neurons labeled with FR were intermingled with those labeled with FG in the lateral part of the SC contralateral to the injection sites. In the stratum griseum intermediale, some of them were double-labeled with both tracers. Our results suggest that SC neurons innervating both the RFp and the cervical spinal cord may be involved in the coordination of head and mouth movements.

Developmental appearance of oligodendrocytes in the embryonic chick retina

The axons of the optic nerve layer are known to be myelinated by oligodendrocytes in the chick retina. The development of the retinal oligodendrocytes has been studied immunohistochemically with antibodies against oligodendrocyte lineage: monoclonal antibodies O4 and O1, and an antibody against myelin basic protein. O4 positive (O4+) cells were first detected in the retina on the tenth day of incubation (embryonic day (E)10, stage 36). The labeled cells were located in the optic nerve layer close to the optic fissure. Most were unipolar in shape, extending a leading process with a growth cone toward the periphery of the retina. By E12, unipolar O4+ cells had spread to the middle of the retina. Many O4+ cells close to the optic fissure showed radial arrangement with extension of processes toward the inner limiting membrane. O1+ oligodendrocytes were first observed in the E14 retina positioned just above (interiorly to) retinal ganglion cells. These labeled cells extended fine processes in the optic nerve layer. Limited numbers of myelin basic protein-positive cells were present by E16 and located interiorly to the retinal ganglion cells. In addition to the oligodendrocyte in the optic nerve layer, a limited number of O4+ cells were observed in the inner nuclear layer by E14, and they became O1+ by E18. Furthermore, explant culture experiments showed E10 to be the youngest stage at which the retina contained oligodendrocyte precursors. An intraventricular inj ection of fluorescent dye 1,1',dioctadecyl-3,3,3',3-tetramethylindocarbocyanine perchlorate (DiI) at E6 yielded O4+/DiI+ cells in the retina at E10, which provided direct evidence to support migration of oligodendrocyte precursor into the retina. The present results demonstrated the sequential appearance of the cells of oligodendrocyte lineage and the detailed morphology of the developing oligodendrocytes in the retina. These morphologic features strongly suggested that retinal oligodendrocytes were derived from the optic nerve and spread by migration through the optic nerve layer.

Nigral axon terminals are in contact with parvicellular reticular neurons which project to the motor trigeminal nucleus in the rat

We examined whether in the rat the descending fibers from the substantia nigra pars reticulata (SNr) were in contact with premotor neurons projecting to the motor trigeminal nucleus (Vm), using a combined anterograde and retrograde tracing technique. After ipsilateral injections of cholera toxin B subunit (CTb) into the Vm and biotinylated dextranamine (BDA) into the SNr, numerous CTb-labeled neurons were distributed bilaterally with slightly ipsilateral dominance in the parvicellular reticular formation (RFp), where many BDA-labeled axons with bouton-like varicosities were found bilaterally with a clear-cut ipsilateral dominance. The overlapping distribution of these labeled axons and neurons was more prominent in the rostral RFp than in the caudal RFp. Within the neuropil of the RFp, some of the BDA-labeled axons made synapses with the somata and proximal dendrites of CTb-labeled neurons. Thus, the present study demonstrated the existence of an indirect pathway from the SNr to the Vm, relayed by the RFp.

Enhancement of neurite outgrowth by the soluble form of human L1 (neural cell adhesion molecule)

L1, a neural cell adhesion molecule, is involved in neurite outgrowth, migration and fasciculation. Although L1 is a membrane glycoprotein expressed on neural cells, the soluble form of L1 is generated in vivo by proteolysis. In the present study, a stable transfectant of Chinese hamster ovary (CHO) cells secreting human L1 without cytoplasmic and membrane spanning domains was generated, and the function of the secreted L1 was examined. Explants from embryonic chick brain stem were cultured on a substrate coated with polyethylenimine (PEI) alone, on substrate-bound L1 or in medium containing soluble L1. The neurites induced by L1, both the substrate-bound form and the soluble form, were 2-3 times longer than those cultured on PEI. The ability of the soluble L1 to induce neurite formation was slightly greater than that of the substrate L1. The present results demonstrated that neurite outgrowth was induced not only by substrate-bound L1 but also by soluble L1. Soluble L1 could be a pharmaceutical candidate for the promotion of nerve regeneration.

Organization of the nigro-tecto-bulbar pathway to the parvicellular reticular formation: a light- and electron-microscopic study in the rat

We examined a nigro-tecto-bulbar pathway to the parvicellular reticular formation (RFp), where many premotor neurons for orofacial motor nuclei are known to be distributed, by using a combined anterograde and retrograde tracing method. After contralateral injections of biotinylated dextranamine (BDA) into the dorsolateral part of the substantia nigra (SNr) and cholera toxin B subunit (CTb) into the RFp, overlapping distributions of BDA-labeled terminals and CTb-labeled neuronal cell bodies were found in the lateralmost part of the superior colliculus (SC) ipsilateral or contralateral to the site of BDA injection or CTb injection, respectively. After contralateral injections of BDA into the SNr and horseradish peroxidase conjugated to wheat germ agglutinin (WGA-HRP) injection into the RFp, ipsilateral labeled axon terminals with BDA were found to make symmetrical synaptic contacts with the somata and dendrites of contralateral labeled neurons with WGA-HRP in the lateralmost part of the SC. Furthermore, we demonstrated that BDA-labeled axon terminals were immunoreactive for GABA, by using the anterograde tracing method combined with immunohistochemistry for GABA. Thus, GABA-like immunoreactive fibers originating from the dorsolateral part of the SNr make monosynaptic contacts with the tectal neurons sending their axons to the RFp.

Early development of the oligodendrocyte in the embryonic chick metencephalon

It has been demonstrated that the spinal cord oligodendrocytes in the vertebrates arise in the ventral ventricular zone adjacent to the floor plate in their early development. Because of the similarities of basic structures in the spinal cord and metencephalon, it is probable that the mode of early oligodendrocyte development in the metencephalon is the same as that in the spinal cord. We examined this possibility in chick embryos, using monoclonal antibodies O1 and O4, markers for oligodendrocyte lineage. An O4-positive (O4+) cell focus was observed in the medial ventricular zone of E5 chick ventral metencephalon (the earliest stage examined), adjacent to the floor plate. At E6, O4+ cells were dispersed from the medial to the lateral pons and, at E7, to the cerebellar anlagen. O4+ cells in the E6 brainstem and in the E7 cerebellum were unipolar in shape, whereas one day later, some of the labeled cells were multipolar with a few thin processes. O1+ oligodendrocytes first appeared at E8 in the ventromedial part of the pons and were distributed throughout the pons at E10 and in the cerebellum at E12. Explants from three subdivisions of the metencephalon (medial and lateral pons, and cerebellum) from E5 to E8 chick embryos were separately cultured to confirm the potential for generation of oligodendrocyte lineage. O4+ cells appeared in the culture of the E5 medial pons (the earliest stage examined), in the E6 lateral pons, and in the E7 cerebellum. In addition, E7 was the youngest stage from which cerebellar explants were able to generate O1+ oligodendrocytes. Our results clearly demonstrated the in vivo morphology of oligodendrocyte precursors in the metencephalon and their developmental appearance in a ventral-to-dorsal manner. From the bipolar morphology of O4+ cells and the spacio-temporal continuity of the dispersion, it is inferred that the initial dispersion of O4+ cells may involve oligodendrocyte migration from the focus of the medial pons to the lateral and dorsal parts of the metencephalon.

Demonstration of the corticotectobulbar pathway from the orofacial motor cortex to the parvicellular reticular formation in the rat

We examined a corticotectobulbar pathway from the orofacial motor cortex (OfM) to the parvicellular reticular formation (RFp), where numerous premotor neurons for the orofacial motor nuclei were known to be distributed, light and electron microscopically by using a combination of anterograde and retrograde tracing techniques. After contralateral injections of biotinylated dextranamine (BDA) into the OfM and cholera toxin B subunit (CTb) into the RFp, the overlapping distribution of ipsilateral axon terminals labeled with BDA and contralateral neurons labeled with CTb was found in the lateralmost part of the superior colliculus (SC). Furthermore, contralateral injections of BDA into the OfM and wheat germ agglutinin-horseradish peroxidase (WGA-HRP) into the RFp resulted in that ipsilateral axons labeled with BDA made asymmetrical synaptic contacts with the dendrites of contralateral SC neurons labeled with WGA-HRP.

A light and electron microscope study of the connections between the preganglionic fibers and the intralingual ganglion cells in the rat

The topographical distribution of the preganglionic neurons sending projection fibers to the tongue, and the connections between their fibers and the intralingual ganglion cells, were examined in the rat. When horseradish peroxidase injections were made into the anterior two-thirds of the tongue, labeled neuronal cell bodies were distributed mainly in the lateral reticular formation at the level between the rostral part of the facial nucleus and the caudal part of the superior olivary complex. On the other hand, after horseradish peroxidase injections into the posterior one-third of the tongue, labeled neuronal cell bodies were found mainly in the rostromedial part of the nucleus of the solitary tract, and additionally in the lateral reticular formation just ventral to the rostral part of the nucleus of the solitary tract. In both cases, labeled neuronal cell bodies were always found in the hypoglossal nucleus. The anterograde tracing study with Phaseolus vulgaris-leucoagglutinin or Fluoro-ruby confirmed the topographical organization suggested by the retrograde tracing study; when the tracer injections were centered on the lateral reticular formation at the level of the rostral part of the facial nucleus or on the rostral part of the nucleus of the solitary tract, labeled fibers distributed mainly in the anterior or posterior part of the tongue, respectively. It was also shown that the axon terminals of the preganglionic fibers labeled with Fluoro-ruby made close contacts with the intralingual ganglion cells immunopositive for neuron specific enolase. The electron microscopy combined with the anterograde tracing method with biotinylated dextran amine further indicated that the preganglionic fibers made synaptic contacts with the soma and dendritic processes of the intralingual ganglion cells.

A nigro-rubro-bulbar pathway to the parvicellular reticular formation in the rat

A possible pathway from the substantia nigra pars reticulata (SNr) to the parvicellular reticular formation (RFp) via the red nucleus (RN) was examined light and electron microscopically by combining anterograde and retrograde tracing techniques. After contralateral injections of biotinylated dextranamine (BDA) into the dorsolateral part of the SNr and cholera toxin B subunit (CTb) into the RFp, many CTb-labelled neurones were distributed contralaterally in the dorsal part of the RN, where numerous BDA-labelled axon terminals originating from the ipsilateral SNr were found. After contralateral injections of BDA into the dorsolateral part of the SNr and wheat germ agglutinin-horseradish peroxidase (WGA-HRP) into the RFp, ipsilateral axons labelled with BDA were found to make synaptic contacts with the somata and dendrites of contralateral neurones labelled with WGA-HRP in the dorsal part of the RN.

Changes of NADPH-diaphorase activity in the lumbosacral intermediolateral neurons of the rat after pelvic axotomy

Changes of nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) activity in the lumbosacral intermediolateral (IML) neurons of the rat were examined for approximately 10 weeks after pelvic nerve transection. Both the number and the staining intensity of NADPH-d-positive neurons in the IML region increased remarkably 1 week after pelvic axotomy; the number of darkly NADPH-d-stained cells on the axotomized side was approximately 2.2-fold greater than on the control side. The number of NADPH-d-positive cells returned to the control level at 5 weeks and decreased significantly below the control level 10-11 weeks postaxotomy. In addition, using a retrograde tracing technique with Fluorogold (FG) combined with NADPH-d histochemistry, approximately 95% of the NADPH-d-positive IML neurons were found to send their axons to the pelvic nerve 1 week after axotomy, whereas nearly 25% of the FG-labeled neurons were found to be negative for NADPH-d. Thus, these results indicate that pelvic axotomy in the rat enhances NADPH-d activity transiently in the IML neurons of the lumbosacral spinal cord, and suggest that the IML region may include different neurons showing different responses in nitric oxide synthase expression after peripheral axotomy.

Characteristics of distribution of peptide-containing nerve fibres in the atrioventricular valves of the rat

The distribution of vasoactive intestinal polypeptide-, neuropeptide Y-, and calcitonin gene-related peptide-immunoreactive nerve fibres was investigated in the atrioventricular valves of the rat. These nerve fibres were visualized by immunostaining of whole-mount preparations by the avidin-biotin-peroxidase complex method. Vasoactive intestinal polypeptide-immunoreactive nerve fibres were observed mainly in the anterior cusp of the mitral valve and, to a lesser extent, in the medial cusp of the tricuspid valve. Numerous neuropeptide Y-immunoreactive nerve fibres were found covering all of the cusps. Both types of peptidergic nerve fibre formed dense networks that consisted of interlacing and anastomosing nerve fibres. Calcitonin gene-related peptide-immunoreactive nerve fibres were seen in every cusp, but did not form a fine network. These results provide detailed anatomical information for evaluation of the possible roles of each type of peptide-containing nerve fibre in the function of atrioventricular valves.

Demonstration of axon collateral projections from the substantia nigra pars reticulata to the superior colliculus and the parvicellular reticular formation in the rat

It was revealed in the rat that single neurons in the substantia nigra pars reticulata (SNr) innervated both the superior colliculus (SC) and the parvicellular reticular formation (RFp) in the pons and medulla oblongata by way of axon collaterals. After injecting Fluoro-gold into the lateral part of the SC and Fluoro-ruby into the RFp on the same side, some SNr neurons were double-labeled with both tracers. They were localized in the dorsolateral part of the caudal half of the SNr ipsilateral to the injection sites.

Co-localization of nitric oxide synthase and vasoactive intestinal peptide immunoreactivity in neurons of the major pelvic ganglion projecting to the rat rectum and penis

Nitric oxide synthase (NOS)- and vasoactive intestinal peptide (VIP)-immunoreactive neurons projecting to the upper rectum or penis were examined using retrograde tracing combined with immunohistochemistry in the major pelvic ganglion of male rats. Five days after injection of Fluoro-Gold (FG) into the upper rectum or penis, the major pelvic ganglion was treated with colchicine. FG injected into the upper rectum labelled many ganglion neurons in the major pelvic ganglion. Immunohistochemistry showed that 37% of FG-labelled neurons were immunoreactive for NOS and 33% for VIP. After injection of FG into the penis, 41% of FG-labelled neurons were immunoreactive for NOS and 25% for VIP. Serial cryostat sections stained for NOS and VIP, respectively, showed the co-localization of NOS and VIP in the ganglion cells projecting to the rectum and penis. In the major pelvic ganglion of the colchicine-treated animals, about 17% of the ganglion cells were immunoreactive for NOS and 32% were immunoreactive for VIP. These neurons were small in diameter (less than 30 microns). A histogram showing cell sizes in cross-sectional areas of NOS-immunoreactive neurons coincided with that of VIP-immunoreactive neurons. Most of the NOS- and VIP-immunoreactive neurons were less than 600 microns. These results indicate that small neurons containing both NOS and VIP in the major pelvic ganglion project to the rectum and penis. In the penile erectile tissues and enteric ganglia, NO and VIP may be released from the same axons and may act concomitantly on the target tissue.

Distribution of extrinsic enkephalin-containing nerve fibers in the rat rectum and their origin in the major pelvic ganglion

The distribution of nerve fibers containing enkephalin (ENK)-like immunoreactivity was examined in the rectum of aganglionosis rats (AGRs) which completely lack the intramural ganglion cells in the large intestine, and was compared with that of their normal littermates. Furthermore, Met5-enkephalin-Arg6-Gly7-Leu8 (MEAGL)-like immunoreactive neurons projecting to the rectum were examined using retrograde tracing combined with immunohistochemistry in the major pelvic ganglion of normal male rats. In the intermuscular space of the aganglionic rectum of AGRs, unlike the pattern of the normal intermuscular plexus, moderate numbers of ENK-like-immunoreactive fibers were arranged in an irregular, coarse network; greatly diminished numbers of immunoreactive fibers were found in the submucosa. No ENK-like-immunoreactive fibers were seen in the circular muscle layer and mucosa. In the normal rat rectum, ENK-like-immunoreactive fibers were seen throughout all layers, and immunoreactive nerve cells were found predominantly in the myenteric plexus of colchicine-treated animals. Fluoro-Gold injected into the upper rectum labelled numerous principal ganglion neurons in the major pelvic and inferior mesenteric ganglia. Less than 10% of tracer-labelled neurons were positive for fluorescein immunolabelling of MEAGL in the major pelvic ganglion; no immunoreactive neurons were found in the inferior mesenteric ganglion. In the major pelvic ganglion of the colchicine-treated normal rats, about 5% of principal ganglion neurons were immunoreactive for MEAGL. Comparison of serial paraffin sections of the major pelvic ganglion stained for tyrosine hydroxylase (TH), MEAGL and vasoactive intestinal polypeptide (VIP), respectively, revealed that more than half of MEAGL-like immunoreactive neurons were also positive for TH; there was no case showing co-existence of MEAGL with VIP in the principal neurons. These results indicate that a small number of enkephalin-containing neurons in the major pelvic ganglion project to the rectum, and that more than half of these neurons are postganglionic sympathetic. They may terminate mainly in the myenteric ganglia in the rectum.

Ultrastructural evidence for innervation of the endothelium and interstitial cells in the atrioventricular valves of the Japanese monkey

BACKGROUND

A rich supply of nerves to the atrioventricular valve has been demonstrated. The role of the valvular nerves is still controversial because the target sites of the nerves have not been confirmed.

METHODS

The innervation of the atrioventricular valves of the Japanese monkey (Macaca fuscata) was examined by acetylcholinesterase staining and electron microscopy. Immunoreactivity for neuropeptide Y (NPY) was also investigated by a post-embedding immunogold method.

RESULTS

The valvular nerve elements were clearly concentrated between the endothelium and interstitial cells on the atrial side of cusps. Naked axon terminals were observed to make direct contact (20-nm gaps) with interstitial cells and also to be in close proximity (approximately 200-nm cleft) to the endothelium. NPY immunoreactivity was clearly detected on the large granular vesicles in some terminals that were in close proximity to interstitial cells and/or the endothelium.

CONCLUSION

The present study suggests that the extensive innervation of the atrioventricular valve, which includes NPY-containing nerves, might affect valvular function via interstitial cells and/or the endothelium.

Descending projections from the superior colliculus to the reticular formation around the motor trigeminal nucleus and the parvicellular reticular formation of the medulla oblongata in the rat

We observed by the anterograde and retrograde tracing techniques in the rat that the lateral part of the superior colliculus (SC), where the nigrotectal fibers from the dorsolateral part of the substantia nigra pars reticulata (SNr) terminated, sent projection fibers to the reticular region around the motor trigeminal nucleus (RFmt) and parvicellular reticular formation (RFp) of the medulla oblongata, where many premotor neurons for the orofacial motor nuclei were known to be distributed. The SC neurons sending their axons to the RFmt and RFp were mainly located in the stratum griseum intermedium, and additionally in the stratum griseum profundum. Our results suggest that neuronal signals conveyed through the nigro-tecto-bulbar pathway to the RFmt and RFp may exert control influences upon oral behavior.

Coexistence of vasoactive intestinal polypeptide and neuropeptide Y immunoreactivity within axon terminals in the canine and human lower esophageal sphincter: electron microscopy by a double immunogold labeling procedure

Subcellular localization of vasoactive intestinal polypeptide (VIP) and neuropeptide Y (NPY) immunoreactivity within nerves was investigated in the lower esophageal sphincter of dogs and humans by double immunogold staining of sections prepared for electron microscopy. Coexistence of VIP and NPY immunoreactivity was clearly demonstrated in the large granular vesicles (LGVs) in axon terminals that were closely associated with the smooth muscle cells, as well as in the LGVs within the perikarya of neurons located in the myenteric plexus. Some LGVs appeared immunopositive only for VIP or NPY. This phenomenon might have been partly due to the fact that the double-labeling procedure with immunogold particles of different sizes was performed on both faces of each section. The results obtained in this study suggest that VIP and NPY are synthesized in the same neuron, stored in the same axon terminal, and released together to act on sphincter muscle cells.

Nerve fibres containing neuropeptide Y in the atrioventricular valves of Japanese monkey and rat; a light and electron microscopic study

Dense distribution of varicose fibres containing neuropeptide Y-like immunoreactivity (NPY-LI) was found in the atrioventricular valves of the Japanese monkey, and moderately in the rat. The immunoelectron microscopy using immunogolds resulted in the localization of NPY-LI within the dense-cored vesicles which existed with the small clear vesicles in the unmyelinated axons near the endocardium. These NPY-LI-containing fibres may participate in regulation of vasomotor role or other functions of the atrioventricular valves.

Cancer cell emboli in the pectoral lymphatics of patients with breast cancer

In order to investigate the possibility of local recurrence in the pectoral muscles of patients who undergo modified radical mastectomies, the cancer cell involvement of the lymphatics associated with the pectoralis major muscle was studied in 39 patients who underwent a standard radical mastectomy for Stage I-III breast cancer. Cancer cell emboli were found in the transpectoral lymphatics of 2 patients (2/39 = 5.1 per cent) and in the pectoral fascial lymphatics of 6 patients (6/39 = 15.4 per cent). Two patients with fascial lymphatic cancer cell emboli were from a group of 14 patients with intramammary lymphatic tumor emboli of a low degree (ly 1). The other 6 patients with cancer cell emboli in either the pectoral fascia or the transpectoral lymphatics were from a group of 11 patients with intramammary lymphatic tumor emboli of a moderate degree (ly 2). There was a significant relationship between the intramammary and the pectoral lymphatic cancer cell emboli (Chi square test: (p less than 0.05). The results of this study therefore indicate that lymphatic cancer cell emboli in the pectoral fascia and muscle are an important risk factor for patients who undergo a modified radical mastectomy.

[A case of carotid body tumor. A review of 84 cases in Japanese literature]

We encountered one case of carotid body tumor. The patient was a 63-year-old man. The tumor was 5 cm X 6 cm in size, and it was strongly adhered to the carotid artery. Therefore, the tumor was removed with combined resection of the adherent lesion of the carotid artery. During the operation, we used a temporary external bypass method to prevent brain damage. The resected part of the carotid artery was reconstructed with saphenous vein graft. Angiogram one year after operation showed good patency of the graft. In Japanese literature, this is the second report of carotid body tumor removed by temporary bypass and the first report of use of a external bypass tube.

[Clinicopathologic study on the mode and degree of invasion of the trachea by thyroid carcinoma]

Among 23 patients with thyroid carcinoma infiltrating to the trachea, total 7 laryngectomy and 16 tracheal resection were carried out, associated with thyroidectomy and neck dissection. The infiltrating mode and degree to the trachea in these patients were classified into 2 types according to the anatomical characteristics: Types of cartilage and membranous portions. Moreover, the former was further subclassified into 3 divisions. The subtype I of cartilage portion: Infiltration to the adventitia of trachea. Histologically, there were 3 well differentiated carcinoma, 3 poorly differentiated carcinoma and one medullary carcinoma. The prognosis was favorable comparing to other types. All 7 patients are alive. The subtype II or III of cartilage portion: Infiltration to the cartilage or annular ligament of trachea. Poorly differentiated carcinoma were noted in 6 of 7 patients. Five are alive and 2 died. The membranous type: Infiltration to the membranous portion of trachea. Esophageal invasion was noted in 7 patients. Undifferentiated carcinomas and squamous cell carcinoma took over a half of the patients. Two are alive and 7 died. The prognosis was the worst.

Surgical clinicopathologic study of malignant fibrous histiocytoma

Fifteen men and six women, ranging in age from 20 to 79 years, with malignant fibrous histiocytoma comprised this series. Amputation of the right lower extremity was performed in one patient, wide resection in 7 and marginal excision in 9, respectively. In the other 4 patients, a non-curative resection was carried out. Adjuvant chemotherapy was prescribed post-operatively for 12 patients. Histologic grade of the surgical specimens was Stage I in 3, II in 6, III in 8 and IV in 4. Among fourteen patients living from 10 months to 9 years and 9 months after the operation, the 7 subjected to a wide resection are all disease free. Seven patients died of a local recurrence or a distant metastases. The survival rate of the patients with Stages I, II is significantly higher than those with Stages III, IV. These results show that a wide resection is to be favored and that staging is useful to estimate the prognosis.

Removal of mesenteric gastrinoma: a case report

A 37-year-old man with a primary mesenteric gastrinoma is reported. A parathyroid adenoma had been removed 13 years ago. Six years earlier the patient underwent an emergency distal gastrectomy because of massive bleeding from a duodenal ulcer. Two months later stomal ulcers developed associated with hypergastrinemia. No gastrinoma was detected and total gastrectomy was performed. The fasting plasma level of gastrin was stable in the range from 580 to 920 pg/ml for the following 5 years. However, the level was found to abruptly increase to 4125 pg/ml. The level increased progressively to 11383 pg/ml within 1 year. A gastrinoma was identified in the jejunal mesenterium, and it was completely removed. After surgery the plasma level of gastrin decreased below the limit of the assay, and the paradoxical response to secretin was no longer observed.

Clinicopathologic study of thyroid carcinoma infiltrating the trachea

Eighteen patients (10 women and 8 men), ranging in age from 37 to 80 years, with thyroid carcinoma infiltrating the trachea comprised this series. Eleven had primary and 7 had recurrent cases. Total laryngectomy was performed in 4 patients, and tracheal resection was carried out followed by end-to-end anastomosis in 13 patients. In one patient, reconstruction was done with Naville's artificial trachea after tracheal resection. Eleven patients were alive after 1 year and 8 months to 6 years and 7 months after the operation. This result was significantly better than that of a group of ten patients without resection of the infiltrated trachea (seven patients died within 6 months). Thus, combined resection of the upper airway improved the prognosis of advanced thyroid carcinoma with tracheal infiltration. Histologic examination of surgical specimens demonstrated well-differentiated carcinoma in seven patients, poorly differentiated carcinoma in seven patients, undifferentiated carcinoma in three patients, and squamous cell carcinoma in one patient. The result showed a higher frequency of poorly differentiated carcinoma than in the control group of 70 patients without tracheal infiltration.

[Clinicopathologic study of thyroid carcinoma infiltrating the trachea]

A clinicopathologic study of 14 cases of thyroid carcinoma with tracheal infiltration and 70 control cases of thyroid carcinoma without tracheal infiltration was performed. The cases with tracheal infiltration were classified into well differentiated carcinoma in 5 cases, poorly differentiated carcinoma in 6, undifferentiated in 2, and squamous cell carcinoma in one, thus showing a higher frequency (54.5%) of poorly differentiated carcinoma than that (11.4%) in the control cases. A comparative study of biological behavior between well differentiated and poorly differentiated carcinomas revealed that the latter was more aggressive, and the lymphnode metastatic rate of which was higher. The prognosis of poorly differentiated carcinoma was poorer than that of well differentiated carcinoma. Selective en bloc resection of the tumor including the larynx and trachea was followed by the improved prognosis of advanced thyroid carcinoma with tracheal infiltration.

Accumulation of hydrocarbon in a patient with adrenoleukodystrophy

The lipid composition of tissues from a patient with adrenoleukodystrophy was examined. Cholesterol esters of both brain and adrenal tissues contained increased proportions of fatty acids longer than C22 in agreement with previous reports. During this study, thin-layer chromatographic analysis of the neutral lipid fraction from the cerebral white matter and the adrenal gland revealed an unknown spot, which was identified as hydrocarbon of n-alkanes (CnH2n + 2, n = 16-33) by means of gas-liquid chromatography and gas chromatography/mass spectrometry. There may be a relationship between the accumulation of hydrocarbons and the change in fatty acid metabolism that is the fundamental disorder of ALD, as: (1) the fatty acids abnormally accumulated in cerebral white matter and adrenal gland coincided in chain length (i.e. C24-C26) with the main peaks of n-alkane in the same tissues, and (2) an abnormal accumulation of n-alkanes occurred in the diseased tissues where cholesterol esters with very long chain fatty acids were markedly increased.

New human papilloma virus isolated from epidermodysplasia verruciformis lesions

Human papilloma virus (HPV) was isolated from red plaques of a patient (N. F.) with epidermodysplasia verruciformis. Electron microscopic examination showed characteristic particles of papilloma virus as icosahedrons about 45 nm in diameter. DNA was extracted from these particles, and closed-circular DNA (Form I) was purified by centrifugation in CsCl containing ethidium bromide. The molecular weight of the DNA was about 5.0 x 10(6). A physical map of the HPV DNA was constructed using several restriction enzymes. The restriction endonuclease cleavage pattern of the HPV DNA was different from those of other types of HPV reported thus far, suggesting that the isolate was a new, as yet unclassified, HPV.